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  Subjects -> ENGINEERING (Total: 2279 journals)
    - CHEMICAL ENGINEERING (191 journals)
    - CIVIL ENGINEERING (185 journals)
    - ELECTRICAL ENGINEERING (101 journals)
    - ENGINEERING (1203 journals)
    - ENGINEERING MECHANICS AND MATERIALS (390 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (65 journals)
    - MECHANICAL ENGINEERING (89 journals)

ENGINEERING (1203 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Full-text available via subscription   (Followers: 5)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 222)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 4)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Artificial Neural Systems     Open Access   (Followers: 4)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 14)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 10)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 20)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 24)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 40)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 37)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 29)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 8)
Applied Clay Science     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
Applied Nanoscience     Open Access   (Followers: 7)
Applied Network Science     Open Access  
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 7)
Arid Zone Journal of Engineering, Technology and Environment     Open Access  
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
Batteries     Open Access   (Followers: 4)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 3)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 9)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 32)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 3)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 14)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 41)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 7)
Case Studies in Thermal Engineering     Open Access   (Followers: 3)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 5)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 4)
Coatings     Open Access   (Followers: 3)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 25)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 255)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 179)
Composites Part B : Engineering     Hybrid Journal   (Followers: 227)
Composites Science and Technology     Hybrid Journal   (Followers: 169)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 13)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 28)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 10)
Computing and Visualization in Science     Hybrid Journal   (Followers: 5)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 29)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 8)
Control Engineering Practice     Hybrid Journal   (Followers: 41)
Control Theory and Informatics     Open Access   (Followers: 7)
Corrosion Science     Hybrid Journal   (Followers: 25)
CT&F Ciencia, Tecnologia y Futuro     Open Access  

        1 2 3 4 5 6 7 | Last

Journal Cover AIChE Journal
  [SJR: 1.122]   [H-I: 120]   [29 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0001-1541 - ISSN (Online) 1547-5905
   Published by John Wiley and Sons Homepage  [1583 journals]
  • Feasible Separation Regions for Distillation I: Structure
    • Authors: Lechoslaw J. Krolikowski
      Abstract: A feasible separation region is determined for only four special combinations of a saturated vapor/liquid feed and total/partial condenser or reboiler. The present work addresses the construction of a feasible separation region for a general case where the feed is a mixture of vapor and liquid in equilibrium and where the column is equipped with a partial/total condenser and reboiler. The analysis reveals that the product composition sets (which are defined for various reflux and reboil ratios and a fixed number of stages in each column section) are the main elements of the feasible separation region. The application of the geometric model of the column in combination with the shape of the distillation line led to the conclusion that the feasible separation region is the union of two product composition sets for both enriching and stripping columns both with an infinite number of stages. The boundary of the feasible separation region consists of several curves related to specific types of operating modes in the column. Some of these curves create a well-known product composition multitude, whereas other curves form a generalized distillation limit. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-19T10:31:02.506929-05:
      DOI: 10.1002/aic.15839
       
  • Structure and Catalytic Consequence of Mg-modified VOx/Al2O3 Catalysts for
           Propane Dehydrogenation
    • Authors: Tengfang Wu; Gang Liu, Liang Zeng, Guodong Sun, Sai Chen, Rentao Mu, Sika Agbotse Gbonfoun, Zhi-Jian Zhao, Jinlong Gong
      Abstract: Supported VOx catalysts are promising non-oxidative propane dehydrogenation (PDH) materials for their commercially attractive activity and propylene selectivity. However, they frequently suffer from rapid deactivation caused by coke deposition. This paper describes the promoting role of magnesium on the stability of VOx/Al2O3 catalysts for PDH. A series of VOx/Al2O3 and Mg-modified VOx/Al2O3 catalysts were synthesized by an incipient wetness impregnation method. The catalysts were carefully characterized by Raman spectra, UV-Vis spectra, STEM, TGA and in situ DRIFTS. We showed that the stability of a 12V/Al2O3 catalyst was significantly improved upon addition of small amounts of MgO. Experimental evidences indicate that V2O5 nanoparticles emerge in the 12V/Al2O3 samples, and appropriate Mg addition helps dispersing the V2O5 nanoparticles into 2D VOx species thus decreasing coke formation and improving stability in non-oxidative dehydrogenation of propane. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-16T11:20:52.05908-05:0
      DOI: 10.1002/aic.15836
       
  • A Highly Stable Metal-Organic Framework with Optimum Aperture Size for CO2
           Capture
    • Authors: Zhigang Hu; Yuxiang Wang, Shamsuzzaman Farooq, Dan Zhao
      Abstract: We herein report an optimal modulated hydrothermal (MHT) synthesis of a highly-stable zirconium metal-organic framework (MOF) with an optimum aperture size of 3.93 Å that is favorable for CO2 adsorption. It exhibits excellent CO2 uptake capacities of 2.50 and 5.63 mmol g−1 under 0.15 bar and 1 bar at 298 K, respectively, which are among the highest of all the pristine water-stable MOFs reported so far. In addition, we have designed a lab-scale breakthrough set-up to study its CO2 capture performance under both dry and wet conditions. The velocity at the exit of breakthrough column for mass balance accuracy is carefully measured using argon with a fixed flow rate as the internal reference. Other factors that may affect the breakthrough dynamics, such as pressure drop and its impact on the roll-up of the weaker component have been studied in details. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-16T11:20:50.948084-05:
      DOI: 10.1002/aic.15837
       
  • A framework for ammonia supply chain optimization incorporating
           conventional and renewable generation
    • Authors: Andrew Allman; Douglas Tiffany, Stephen Kelley, Prodromos Daoutidis
      Abstract: Ammonia is an essential nutrient for global food production brought to farmers by a well established supply chain. This paper introduces a supply chain optimization framework which incorporates new renewable ammonia plants which produce hydrogen from wind-powered electrolysis into the conventional ammonia supply chain. Both economic and environmental objectives are considered. The framework is then applied to two separate case studies analyzing the supply chains of Minnesota and Iowa, respectively. The base case results present an expected tradeoff between cost, which favors purchasing ammonia from conventional plants, and emissions, which favor building distributed renewable ammonia plants. Further analysis of this tradeoff shows that a carbon tax above $25/t will reduce emissions in the optimal supply chain through building large renewable plants. The importance of scale is emphasized through a Monte Carlo sensitivity analysis, as the largest scale renewable plants are selected most often in the optimal supply chain. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-16T11:20:23.663565-05:
      DOI: 10.1002/aic.15838
       
  • Advice for Emerging Researchers on Research Program Development: A
           Personal Case Study
    • Authors: Christopher W. Jones
      PubDate: 2017-06-15T17:15:30.012427-05:
      DOI: 10.1002/aic.15835
       
  • How Nano-Scale Roughness Impacts the Flow of Grains influenced by
           Capillary Cohesion
    • Authors: Casey Q. LaMarche; Andrew W. Miller, Peiyuan Liu, Stuart Leadley, Christine M. Hrenya
      Abstract: We show that nano-scale changes in surface roughness affect the macro-scale (many-particle) behavior of granular materials influenced by cohesion. Macro-scale effects of roughness are investigated for conditions where cohesion is dominated by either humidity-induced or van der Waals-induced forces. Surface-topography measurements are used to calculate the relevant inter-particle cohesive forces. The (force-dominated) macro-scale cohesion measurements are explained via the ratio of the predicted inter-particle cohesive force to gravity, thus reinforcing the importance of roughness to cohesion. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-13T10:46:24.016806-05:
      DOI: 10.1002/aic.15830
       
  • Integrating the Physics with Data Analytics for the Hybrid Modelling of
           the Granulation Process
    • Authors: Wafa' H. AlAlaween; Mahdi Mahfouf, Agba D. Salman
      Abstract: A hybrid model based on physical and data interpretations to investigate the high shear granulation (HSG) process is proposed. This model integrates three separate component models, namely, a computational fluid dynamics model, a population balance model and a radial basis function model, through an iterative procedure. The proposed hybrid model is shown to provide the required understanding of the HSG process, and to also accurately predict the properties of the granules. Furthermore, a new fusion model based on integrating fuzzy logic theory and the Dempster-Shafer theory is also developed. The motivation for such a new modelling framework stems from the fact that integrating predictions from models which are elicited using different paradigms can lead to a more robust and accurate topology. As a result, significant improvements in prediction performance have been achieved by applying the proposed framework when compared to single models. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-13T10:46:22.984935-05:
      DOI: 10.1002/aic.15831
       
  • An Efficient and Reliable Predictive Method for Fluidized Bed Simulation
    • Authors: Liqiang Lu; Tingwen Li, Sofiane Benyahia
      Abstract: In past decades, the continuum approach was the only practical technique to simulate large-scale fluidized bed reactors because discrete approaches suffer from the cost of tracking huge numbers of particles and their collisions. This study significantly improved the computation speed of discrete particle methods in two steps: First, the time-driven hard-sphere (TDHS) algorithm with a larger time-step is proposed allowing a speedup of 20-60 times; second, the number of tracked particles is reduced by adopting the coarse-graining technique gaining an additional 2-3 orders of magnitude speedup of the simulations. A new velocity correction term was introduced and validated in TDHS to solve the over-packing issue in dense granular flow. The TDHS was then coupled with the coarse-graining technique to simulate a pilot-scale riser. The simulation results compared well with experiment data and proved that this new approach can be used for efficient and reliable simulations of large-scale fluidized bed systems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-13T10:46:20.017741-05:
      DOI: 10.1002/aic.15832
       
  • The Development of Kinetics Model for CO2 Absorption into Tertiary Amines
           containing Carbonic Anhydrase
    • Authors: Bin Liu; Xiao Luo, Zhiwu Liang, Wilfred Olson, Helei Liu, Raphael Idem, Paitoon Tontiwachwuthikul
      Abstract: CO2 absorption into aqueous solutions of two tertiary alkanolamines, namely, MDEA and DMEA with and without carbonic anhydrase (CA) was investigated with the use of the stopped-flow technique at temperatures in the range of 293-313 K, CA concentration varying from 0-100 g/m3 in aqueous MDEA solution with the amine concentration ranging from 0.1-0.5 kmol/m3, and CA concentration varying from 0-40 g/m3 in aqueous DMEA solution with the amine concentration ranging from 0.05-0.25 kmol/m3. The results show that the pseudo first-order reaction rate (k0, amine; s−1) is significantly enhanced in the presence of CA as compared with that without CA. The enhanced values of the kinetic constant in the presence of CA has been calculated and a new kinetics model for reaction of CO2 absorption into aqueous tertiary alkanolamine solutions catalyzed by CA has been established and used to make comparisons of experimental and calculated pseudo first-order reaction rate constant (k0, with CA) in CO2-MDEA-H2O and CO2-DMEA-H2O solutions. The AADs were 15.21% and 15.17% respectively. The effect of pKa on the CA activities has also been studied by comparison of CA activities in different tertiary amine solutions, namely, TEA, MDEA, DMEA and DEEA. The pKa trend for amines were: DEEA>DMEA>MDEA>TEA. In contrast the catalyst enhancement in amines was in the order: TEA> MDEA> DMEA> DEEA. Therefore, it can be seen that the catalyst enhancement in the amines decreased with their increasing pKa values. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-13T10:46:15.564291-05:
      DOI: 10.1002/aic.15833
       
  • Self-Similar Breakup of Viscoelastic Thread for Droplet Formation in
           Flow-Focusing Devices
    • Authors: Wei Du; Taotao Fu, Qindan Zhang, Chunying Zhu, Youguang Ma, Huai Z. Li
      Abstract: The self-similarity of the breakup of viscoelastic dispersed thread for droplet formation in flow-focusing devices is investigated experimentally. A high-speed camera is used to capture the evolution and angles of the cone-shaped liquid-liquid interface. The self-similar profiles for the liquid-liquid interface are obtained by normalizing the interface with the minimum width of the dispersed thread. The breakup of the dispersed thread transfers from a self-similar power law scaling stage with an exponent of 0.36 to a self-similar exponential scaling stage. The asymptotic cone angles prior to final breakup are consistent with the value of 125.5° and 151°, respectively. The viscoelasticity inhibits the development of finite-time singularity for the breakup of the liquid-liquid interface at microscale, similar to the capillary breakup at macroscale. The results demonstrate that the breakup of the viscoelastic dispersed thread for droplet formation exhibits self-similarity at microscale. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-13T10:46:10.038121-05:
      DOI: 10.1002/aic.15834
       
  • Investigation of Hydrodynamics in Bubble Column with Internals using
           Radioactive Particle Tracking (RPT)
    • Authors: Dinesh V. Kalaga; H.J. Pant, Sameer V. Dalvi, Jyeshtharaj B. Joshi, Shantanu Roy
      Abstract: Even though many experimental investigations are reported on this subject of liquid velocity patterns in bubble columns, most of the reported work is restricted to measurements at the near wall regions, columns without internals, and in low dispersed phase holdups. In the present work, a non-invasive Radioactive Particle Tracking (RPT) technique was employed to quantify the hydrodynamic parameters in 120 mm diameter bubble column with, and without vertical rod internals, using air/water system as the working fluids. The superficial air velocities cover a wide range of flow regimes: from 14 mm/s to 265 mm/s. Experiments were performed for four internals configurations with percentage obstruction area varied from 0 (without internals) to 11.7%. We report that the liquid phase hydrodynamics depends strongly on superficial gas velocity and internals. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-12T11:01:25.58851-05:0
      DOI: 10.1002/aic.15829
       
  • Prediction of thermodynamic properties of aqueous electrolyte solutions
           using equation of state
    • Authors: Reza Shahriari; Mohammad Reza Dehghani
      Abstract: In this study, a predictive model is presented for estimation of second order thermodynamic properties of electrolyte solutions. In order to provide a comprehensive understanding, the capability of modified electrolyte PC-SAFT up to high pressure and temperature has been studied. In addition to the first order derivative thermodynamic properties, the Gibbs free energy, enthalpy and heat capacity of aqueous electrolyte solutions at infinite dilution are predicted. Using new methodology, the dielectric constant is modified to keep the pressure, temperature and ionic strength dependency. Our results show that the Born term has a significant contribution on prediction of second order derivative properties. Meanwhile the impact of temperature-dependent solution dielectric constant on standard state heat capacity is studied. Finally, the isobaric heat capacity at various salt concentrations is predicted without any adjustable parameters. The results of this work indicate an acceptable agreement with experimental data especially at high pressure and temperature. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-09T06:33:48.954317-05:
      DOI: 10.1002/aic.15827
       
  • On Air Entrainment in a Water pool by Impingement of a Jet
    • Authors: Vatsal Sanjay; Arup Kumar Das
      Abstract: Air entrainment due to impingement of a water jet on a pool is studied extensively to understand the physics of the initiation and the cluster of bubbles formed below the free surface. Possible outcomes due to the jet impingement in a pool have been identified as smooth free surface without entrainment or formation of rigorous bubble cluster below the jet-pool contact. Triangular entrained region is found to be a three-dimensional association of disconnected bubble population continuously breaking and making with the neighbors. A correlation for prediction of maximum entrained height for a range of jet diameters and lengths is proposed. The trajectory of a single bubble is also studied to understand the kinematics of the bubble cluster. Alongside, an electrical conductivity probe has been used to examine the probabilistic presence of the bubble at a given depth in the liquid pool. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-08T22:21:54.436622-05:
      DOI: 10.1002/aic.15828
       
  • Comment on Xu et al. 2017
    • Authors: Christopher J. Landry; Maša Prodanović, Peter Eichhubl
      PubDate: 2017-06-08T21:40:44.879544-05:
      DOI: 10.1002/aic.15823
       
  • Inhomogeneous distribution of platinum and ionomer in the porous cathode
           to maximize the performance of a PEM fuel cell
    • Authors: Lei Xing; Prodip K. Das, Keith Scott, Weidong Shi
      Abstract: A proton exchange membrane (PEM) fuel cell model, accounting for the combined water transport mechanism, ionomer swelling, water phase-transfer, two-phase flow and transport processes, is developed. The inhomogeneous distributions of Pt and ionomer inside the catalyst layer (CL) are numerically studied to achieve an optimal cell performance for two types of oxygen reduction reaction catalysts at different loadings. Results indicate that the optimal variation in loading through the thickness of the electrode (slopes) of Pt catalyst and ionomer vary with conditions of operation. An optimal platinum slope increases the agglomerate effectiveness factor and decreases the second Damköhler number near the CL-membrane interface. An optimal ionomer slope increases the CL porosity near the GDL-CL interface and decreases the mass transport resistance of reactant through the ionomer film. Their interaction shows that the optimal platinum slope is a tradeoff between the electrochemical active surface area and porosity at high current densities. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-07T10:35:47.39902-05:0
      DOI: 10.1002/aic.15826
       
  • The effect of the size of square microchannels on hydrodynamics and mass
           transfer during liquid-liquid slug flow
    • Authors: Mehdi Sattari-Najafabadi; Mohsen Nasr Esfahany, Zan Wu, Bengt Sundén
      Abstract: The present study investigated the influence of square microchannel size on hydrodynamics and mass transfer in the liquid-liquid slug flow regime. Three square microchannels with the hydraulic diameters of 200, 400 and 600 µm were used. The employed method for estimating mass transfer coefficients remarkably increased the accuracy of the results. The findings revealed that decreasing the microchannel size improved the interfacial area due to plug length enlargement and deteriorated mass transfer resistances because of augmented internal circulations, leading to the considerable enhancement of mass transfer coefficients. The increasing effect on the overall mass transfer coefficient became greater with flow velocity, showing that size effect on mass transfer resistances was more profound at higher flow velocities. The influence of size on the interfacial area was significantly greater than that on mass transfer resistances due to the significant increment of wall film length with the decrease in channel size. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-07T10:35:43.204206-05:
      DOI: 10.1002/aic.15822
       
  • Coaxial Electrohydrodynamic Atomization towards Large Scale Production of
           Core-shell Structured Microparticles
    • Authors: Wei-Cheng Yan; Yen Wah Tong, Chi-Hwa Wang
      Abstract: In this work, a double-nozzle coaxial electrohydrodynamic atomization (CEHDA) system was designed as an instructive case towards large-scale production of core-shell microspheres. The effect of nozzle-to-nozzle distance was investigated to reveal that the interference between neighboring nozzles significantly affect the product quality in terms of morphology and core-shell structure. Optimal spacing indicated that ∼3000 nozzle/m2 packing density may be achieved with minimum interference of electric field from neighboring nozzle by adjusting the nozzle-to-nozzle distance greater than 0.018m. The proposed multi-scale model also showed that the X-component of electric field strength (Ex) at the region near side nozzles increases with increasing nozzle number, and the bending of jets/sprays at the side may be reduced by using dummy nozzle at the edge side. The model could guide the design of multi-nozzle CEHDA system for production of core-shell microparticles in large-scale. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-07T10:30:27.034469-05:
      DOI: 10.1002/aic.15821
       
  • Quantitative dependence of CH4-CO2 dispersion on immobile water fraction
    • Authors: Marco Zecca; Sarah J. Vogt, Abdolvahab Honari, Gongkui Xiao, Einar O. Fridjonsson, Eric F. May, Michael L. Johns
      Abstract: Enhanced Gas Recovery (EGR) involves CO2 injection into natural gas reservoirs to both increase gas recovery and trap CO2. EGR viability can be determined by reservoir simulations; however these require a description of fluid dispersion (mixing) between the supercritical CO2 and natural gas. Here we quantify this dispersivity (α) in sandstone rock plugs as a function of residual water fraction. To ensure the accuracy of such data, we designed a novel core flooding experimental protocol that ensured an even spatial distribution of water, minimised erroneous entry/exit contributions to mixing, and minimised dissolution of the CO2 into the water phase. Dispersivity was found to increase significantly with water content, although the differences in α between sandstones were eliminated upon the inclusion of residual water. This enabled development of a correlation between α and water content and, hence, between the dispersion coefficient and Peclet number that is readily incorporable into reservoir simulations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-07T10:30:25.804003-05:
      DOI: 10.1002/aic.15824
       
  • Process Design and Control optimization: A simultaneous approach by
           multi-parametric programming
    • Authors: Nikolaos A. Diangelakis; Baris Burnak, Justin Katz, Efstratios N. Pistikopoulos
      Abstract: We present a framework for the application of design and control optimization via multiparametric programming through four case studies. We develop design dependent multi-parametric model predictive controllers that are able to provide the optimal control actions as functions of the system state and the design of the process at hand, via our recently introduced PAROC framework1. The process and the design dependent explicit controllers undergo a Mixed Integer Dynamic Optimization (MIDO) step for the determination of the optimal design. The result of the MIDO is the optimal design of the process under optimal operation. We demonstrate the framework through case studies of a tank, a continuously stirred tank reactor, a binary distillation column and a residential cogeneration unit. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-07T10:30:19.334695-05:
      DOI: 10.1002/aic.15825
       
  • Issue information
    • Abstract: Cover illustration. Professional skills, often under-valued in school, are critically important in practice. Graphic by Andrew Grossmann; image supplied by the American Institute of Chemical Engineers.10.1002/aic.15747
      PubDate: 2017-06-06T14:25:53.395817-05:
      DOI: 10.1002/aic.15475
       
  • Process Flow-Sheet Synthesis: Systems-Level Design applied to Synthetic
           Crude Production
    • Authors: James Alistair Fox; Diane Hildebrandt, David Glasser, Bilal Patel
      Abstract: This paper showcases a novel approach for conceptual design for process flow-sheets at the “systems-level”.A graphical technique, called the “GH-space”, is used to analyze the flows of material, heat and work within a process to provide insight into the interactions of various units within the process.Any unit process, which interacts with the surroundings by transferring heat and work, can be represented as a vector on the GH-space. While material and energy balances are normally performed on a flowsheet, this vectored approach allows the material and energy balances to be used to construct a flowsheet.This paper focuses on using the GH-space to synthesis a synthetic fuels flowsheet.It was shown that a process could be designed that not only produced the desired product but could also consume carbon dioxide as a feed, along with the feeds of methane and oxygen, and could even potentially generate electricity. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-06T01:05:36.912082-05:
      DOI: 10.1002/aic.15818
       
  • Heat Assisted Twin Screw Dry Granulation
    • Authors: Y. Liu; M. R. Thompson, K.P. O'Donnell, S. Ali
      Abstract: A new ‘assisted' dry granulation method has been devised for the twin-screw granulator. The method may be beneficial to drug preparation as it limits heat exposure to only one barrel zone, much shorter than melt granulation. Its mechanism was investigated using four placebo formulations, each containing a polymer binder with a glass transition temperature lower than 130°C. Variables of study included screw configuration, screw speed, barrel zone temperature and moisture content. Granulated samples were characterized for size and porosity while feed powders were examined for their thermal transitions, inter-particle friction, cohesion, and sintering rate. Results indicated that granule coalescence relied upon melting of polymer binder in the kneading blocks by a combination of heat conducted from barrel and generated from screw speed friction. Successful granulation was possible with minimal addition of water, though varying the moisture content showed the relevance of the polymer's glass transition temperature and sintering progress. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-05T10:56:39.411745-05:
      DOI: 10.1002/aic.15820
       
  • Transferable Potentials for Phase Equilibria. Improved United-Atom
           Description of Ethane and Ethylene
    • Authors: Mansi S. Shah; Michael Tsapatsis, J. Ilja Siepmann
      Abstract: A more accurate version of the Transferable Potentials for Phase Equilibria – United Atom force field, called TraPPE–UA2, for ethane and ethylene is presented. Very similar molecular volumes, shapes, and self- and cross-interaction strengths of ethane and ethylene make their separation fundamentally interesting and industrially challenging. Separation factors as low as 1.5–3.0 necessitate very accurate molecular models in order to be able to computationally design potential separation processes. Additional force field parameters, namely the distance between the Lennard-Jones sites for both compounds and partial charges only for ethylene, are introduced in the parameterization and different combining rules for the Lennard-Jones interaction are considered. In addition to the liquid densities and critical temperature, the training set also includes saturation vapor pressures to yield an accurate two-site ethane model. Binary ethane/ethylene, CO2/ethylene, and H2O/ethylene vapor–liquid equilibria and H2O/ethylene dimer calculations are used for further optimization of a four-site ethylene model. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-05T10:50:33.246746-05:
      DOI: 10.1002/aic.15816
       
  • Predicting Phase Behavior in Aqueous Systems without Fitting Binary
           Parameters II: Gases and Non-Aromatic Hydrocarbons
    • Authors: Ilya Polishuk; Helena Lubarsky, Dong NguyenHuynh
      Abstract: This investigation continues a series of studies evaluating the capability of the recently proposed CP-PC-SAFT and sPC-SAFT of Liang et al. to estimate the thermodynamic properties of aqueous systems in the entirely predictive manner. Similarly to the previously considered systems, CP-PC-SAFT remains a realistic estimator of the available data on critical loci, HTHP phase equilibria and volumetric properties also in the cases of non-polar gases and non-aromatic hydrocarbons from argon and nitrogen till n-eicosane and squalene while keeping zero values of binary parameters. Nevertheless, such application of the model poses certain unavoidable compromises on its accuracy. Inter alia, CP-PC-SAFT is a particularly inaccurate estimator of the water-rich liquid phases away from the critical points. sPC-SAFT predicts these data in a more reliable manner. Moreover, its predictive capability goes beyond the liquid phases and it exhibits a remarkable accuracy in forecasting various phase equilibria below the critical point of water. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-05T10:50:29.895255-05:
      DOI: 10.1002/aic.15815
       
  • Analysis of the Effect of Small Amounts of Liquid on Gas-Solid
           Fluidization using CFD-DEM Simulations
    • Authors: C. M. Boyce; A. Ozel, J. Kolehmainen, S. Sundaresan
      Abstract: Gas-solid fluidization involving small amounts of liquid is simulated using a CFD-DEM model. The model tracks the amount of liquid on each particle and wall element and incorporates finite rates of liquid transfer between particles and pendular liquid bridges which form between two particles as well as between a particle and a wall element. Viscous and capillary forces due to these bridges are modeled. Fluidization-defluidization curves show that minimum fluidization velocity and defluidized bed height increase with Bond number (Bo), the ratio of surface tension to gravitational forces, due to cohesion and inhomogeneous flow structures. Under fluidized conditions, hydrodynamics and liquid bridging behavior change dramatically with increasing Bo, and to a lesser extent with capillary number, the ratio of viscous to surface tension forces. Bed fluidity is kept relatively constant across wetting conditions when one maintains a constant ratio of superficial velocity to minimum fluidization velocity under wet conditions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-05T10:50:26.631774-05:
      DOI: 10.1002/aic.15819
       
  • A molecular-thermodynamic approach to predict the micellization of binary
           surfactant mixtures containing amino sulfonate amphoteric surfactant and
           nonionic surfactant
    • Authors: Zhao Hua Ren
      Abstract: A molecular-thermodynamic approach was adopted to predict the value of mixed critical micelle concentration (cmc) for the binary surfactant mixtures constituted by an amino sulfonate amphoteric surfactant, sodium 3-(N-dodecyl ethylenediamino)-2-hydropropyl sulfonate (abbr. C12AS), and a nonionic surfactant, octylphenol polyethylene ether (OP-n, where n denotes the average number of oxyethylene glycol ether). In this investigation, considering two positive charges on the hydrophilic group of C12AS, which is unlike to conventional zwitterionic surfactants having one positive charge (such as, alkylbetaine, etc.), three schemes were designed to obtain the geometric parameter describing the dipole structure of C12AS. According to the selected optimum scheme, four cases corresponding to the different conformations of both the headgroup and the hydrocarbon chain of surfactant were discussed. The results show that the predicted value of mixed cmc for the C12AS/OP-n mixtures agrees well with the experiment value. The deviation of the predicted value from the experimental value can be explained by the effect of the hydrophilicity of OP-n on the process of micellization. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-05T10:50:25.382569-05:
      DOI: 10.1002/aic.15817
       
  • Pipe Flow of a Dense Emulsion: Homogeneous Shear-Thinning or Shear-Induced
           Migration'
    • Authors: Micheline Abbas; Amélie Pouplin, Olivier Masbernat, Alain Liné, Sandrine Décarre
      Abstract: The flow field of a 70% concentrated non-colloidal o/w emulsion in a pipe has been investigated by means of PIV in a matched refractive index medium. At steady state and in laminar regime, the shape of axial velocity profiles is not parabolic and exhibits a shear-thinning behavior of the dense emulsion, with a flow index of 0.5 and a negligible yield stress (less than 1 Pa). However, instead of a square root law, the pressure drop increases linearly with Um. To explain this apparent inconsistency, two mechanisms of different nature are considered. The first originates from a possible relation between the consistency factor and the drop mean diameter. The second mechanism is shear-induced migration and leads to the development of a concentration gradient in the pipe cross-section. Both mechanisms considered reconcile the experimental data, the apparent local shear-thinning behavior and the linear evolution of the pressure drop with the flowrate. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T08:05:43.559059-05:
      DOI: 10.1002/aic.15811
       
  • How graphical analysis helps interpreting optimal experimental designs for
           nonlinear enzyme kinetic models
    • Authors: Rüdiger Ohs; Jan Wendlandt, Antje C. Spiess
      Abstract: Progress curve experiments combined with optimal experimental design (OED) are an efficient approach to determine enzyme kinetics. However, it is hardly possible to verify why specific experiments are suggested for nonlinear enzyme kinetic model identification. Therefore, we systematically investigated the surface and contour plots of the sensitivities and of the OED criteria which are based on sensitivities. The model reaction was an enzyme catalyzed self-ligation of aldehydes to chiral 2-hydroxyketones. The visualization improved the understanding of OED and allowed for deducing and confirming five suggestions for kinetic identification: 1. Avoid experiments vicinal to the reaction equilibrium, 2. Choose the design space as large as possible, 3. Prefer D(eterminant)- and E(igenvalue)-criteria over the A(verage)-criterion, 4. Apply enzyme concentrations such that the reaction does not complete too fast, and 5. Few optimal experiments result in significantly improved parameter estimations. The graphical analysis also provides information about selecting appropriate optimization algorithms. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T07:20:55.076931-05:
      DOI: 10.1002/aic.15814
       
  • Prediction of Maximum Recoverable Mechanical Energy via Work Integration:
           A Thermodynamic Modeling and Analysis Approach
    • Authors: Aida Amini-Rankouhi; Yinlun Huang
      Abstract: Thermal energy and mechanical energy are two common forms of energy consumed significantly in the process industries. While thermal energy can be effectively recovered using matured heat integration technologies, recovery of mechanical energy through work integration has not been fully explored. It is shown that work integration can be achieved through synthesizing work exchange networks (WENs), where work exchangers are operated in a batch mode, and compressors and expanders are operated in a continuous mode; this renders network synthesis a very sophisticated design task. It is greatly beneficial if the maximum amount of mechanical energy recoverable by a WEN can be determined prior to network design. In this paper, we introduce a thermodynamic modeling and analysis method to identify accurately the maximum amount of recoverable mechanical energy of any process system of interest. The method is rigorous and general for target setting of mechanical energy recovery prior to WEN synthesis. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T07:15:28.453717-05:
      DOI: 10.1002/aic.15813
       
  • Integrated B2B-NMPC Control Strategy for Batch/Semi-batch Crystallization
           Processes
    • Authors: Qinglin Su; Richard D. Braatz, Min-Sen Chiu
      Abstract: The uncertainty in crystallization kinetics is of major concern in manufacturing processes, which can result in deterioration of most model-based control strategies. In this study, uncertainties in crystallization kinetic parameters were characterized by Bayesian probability distributions. An integrated B2B-NMPC control strategy was proposed to first update the kinetic parameters from batch to batch using a multiway partial least squares (MPLS) model, which described the variances of kinetic parameters from that of process variables and batch-end product qualities. The updated process model was then incorporated into an NMPC design, the extended prediction self-adaptive control (EPSAC), for online control of the final product qualities. Promising performance of the proposed integrated strategy was demonstrated in a simulated semi-batch pH-shift reactive crystallization process to handle major crystallization kinetic uncertainties of L-glutamic acid, wherein smoother and faster convergences than the conventional B2B control were observed when process dynamics were shifted among three scenarios of kinetic uncertainties. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T06:40:49.987292-05:
      DOI: 10.1002/aic.15810
       
  • Transitional Flow in a Rushton Turbine Stirred Tank
    • Authors: Yulong Zhang; Zhengming Gao, Zhipeng Li, J.J. Derksen
      Abstract: The way in which the single phase flow of Newtonian liquids in the vicinity of the impeller in a Rushton turbine stirred tank goes through a laminar – turbulent transition has been studied in detail experimentally (with Particle Image Velocimetry, PIV) as well as computationally. For Reynolds numbers equal to or higher than 6,000, the average velocities and velocity fluctuation levels scale well with the impeller tip speed, i.e. show Reynolds independent behavior. Surprising flow structures were measured – and confirmed through independent experimental repetitions – at Reynolds numbers around 1,300. Upon reducing the Reynolds number from values in the fully turbulent regime, the trailing vortex system behind the impeller blades weakens with the upper vortex weakening much stronger than the lower vortex. Simulations with a variety of methods (direct numerical simulations, transitional turbulence modeling) and software implementations (ANSYS-Fluent commercial software, lattice-Boltzmann in-house software) have only partial success in representing the experimentally observed laminar – turbulent transition. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T06:40:31.314913-05:
      DOI: 10.1002/aic.15809
       
  • Sonochemical Effect Induced by Hydrodynamic Cavitation: Comparison of
           Venturi/Orifice Flow Geometries
    • Authors: Sandip K. Pawar; Amit V. Mahulkar, Kuldeep Roy, Vijananand S. Moholkar, Aniruddha B. Pandit
      Abstract: This study presents comparative assessment of four cavitation devices (3 venturis and an orifice) in terms of cavitational yield. A 4-fold approach was adopted for assessment, viz. CFD simulations of cavitating flow, simulations of individual cavitation bubble dynamics, high speed photographs of cavitating flow and model reaction of potassium iodide oxidation. Influence of design parameters of cavitation devices on nature of cavitation produced in the flow was studied. Number density of cavitation bubbles in the flow and interactions among bubbles had critical influence on cavitation yield. Orifice gave the highest cavitational yield per unit energy dissipation in flow (despite lower working inlet pressure) due to low density of cavitation bubbles in flow. On contrary, occurrence of large cavitation bubble clouds in venturi flow had adverse effect on cavitational yield due to high interactions among cavitation bubbles resulting in inter-bubble coalescence and recombination of oxidizing radicals generated from cavitation bubbles. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T06:40:29.434247-05:
      DOI: 10.1002/aic.15812
       
  • Two-dimensional modelling of an absorbing falling film in its development
           zone
    • Authors: C. Wylock; B. Scheid
      Abstract: This work presents the modelling of a vertical falling film expanding or shrinking from the inlet manifold. Considering a stationary approach, the film shape, the flow field and the absorption rate of an ambient gas are computed. For the flow field, 1D second-order weighted integral boundary layer (WIBL) model is shown to accurately reproduce the film deformations. The gas transfer is then solved in a 2D pre-deformed domain in order to investigate the impact of the film deformations on the gas absorption rate. It is found that a significant mass transfer enhancement, as compared to a flat film, is obtained when the film is expanding due to the concomitant increase of the concentration gradient along the interface. On the contrary, a slight hindrance of the mass transfer is observed when the film is shrinking, though it remains in this case very close to the flat film analytical solution. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-30T10:40:33.173292-05:
      DOI: 10.1002/aic.15808
       
  • Hydrodynamics of Gas-Liquid Flow in Micro-Packed Beds: Pressure Drop,
           Liquid Holdup and Two-Phase Model
    • Authors: Jisong Zhang; Andrew R. Teixeira, Lars Thilo Kögl, Lu Yang, Klavs F. Jensen
      Abstract: Hydrodynamics of gas-liquid two-phase flow in micro-packed beds are studied with a new experimental setup. The pressure drop, residence time distribution and liquid holdup are measured with gas and liquid flow rates varying from 4 to 14 sccm and 0.1 to 1 ml/min, respectively. Key parameters are identified to control the experimentally observed hydrodynamics, including transient start-up procedure, gas and liquid superficial velocities, particle and packed bed diameters and physical properties of the liquids. Contrary to conventional large packed beds, our results demonstrate that in these micro-systems, capillary forces have a large effect on pressure drop and liquid holdup, while gravity can be neglected. A mathematical model describes the hydrodynamics in the micro-packed beds by considering the contribution of capillary forces, and its predictions are in good agreement with experimental data. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-26T19:40:24.715805-05:
      DOI: 10.1002/aic.15807
       
  • Experimental Proof of the Existence of Mass Transfer Resistance During
           Early Stages of Ethylene Polymerization with Silica supported
           Metallocene/MAO Catalysts
    • Authors: Muhammad Ahsan Bashir; Vincent Monteil, Christophe Boisson, Timothy F. L. McKenna
      Abstract: The size of a silica supported metallocene/MAO catalyst plays an important role in determining its productivity during ethylene polymerization. From a chemical engineering point of view, this size dependency of catalytic activity of supported metallocenes is mathematically connected with the different levels of mass transfer resistance in big and small catalyst particles but no experimental evidence has been provided to date. The results of the present systematic experimental study clearly demonstrate that the intraparticle monomer diffusion resistance is high in bigger catalyst particles during initial instants of ethylene polymerization and diminishes with the passage of polymer particle growth. Two different silica supported metallocene/MAO catalysts provided the same results while highlighting the fact that catalyst chemistry should be carefully considered while studying complex chemical engineering problems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-26T19:35:27.09659-05:0
      DOI: 10.1002/aic.15806
       
  • Molecular Transport through Mixed Matrix Membranes: A Time-Dependent
           Density Functional Approach
    • Authors: Yu Liu; Fangyuan Guo, Jun Hu, Honglai Liu, Ying Hu
      Abstract: The transport properties of gases in mixed matrix membranes (MMMs) are important in materials design. Here, we developed a novel time-dependent density functional theory (TDDFT) method to study the transport properties of gases in MMMs. The MMM is modeled by inserting a spherical filler into the continuous polymer phase, which is similar to the Maxwell model; additionally, the inhomogeneity of the filler and the molecular correlations were taken into account in the TDDFT method. Transport properties such as permeation, density profile, flux and chemical potential are examined and discussed. We found that the TDDFT prediction of the permeation is higher than that of the Maxwell model, and the filler-polymer interface is key to tuning this effect, which also seems to be the dominating factor in the transport process on both the microscopic and macroscopic scale. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-25T17:19:21.867528-05:
      DOI: 10.1002/aic.15805
       
  • Stochastic Programming Models for Optimal Shale Well Development and
           Refracturing Planning under Uncertainty
    • Authors: Markus G. Drouven; Diego C. Cafaro, Ignacio E. Grossmann
      Abstract: In this work we present an optimization framework for shale gas well development and refracturing planning. This problem is concerned with if and when a new shale gas well should be drilled at a prospective location, and whether or not it should be refractured over its lifespan. We account for exogenous gas price uncertainty and endogenous well performance uncertainty. We propose a mixed-integer linear, two-stage stochastic programming model embedded in a moving horizon strategy to dynamically solve the planning problem. A generalized production estimate function is described that predicts the gas production over time depending on how often a well has been refractured, and when exactly it was restimulated last. From a detailed case study, we conclude that early in the life of an active shale well, refracturing makes economic sense even in low-price environments, whereas additional restimulations only appear to be justified if prices are high. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-25T17:00:27.32088-05:0
      DOI: 10.1002/aic.15804
       
  • Gravity Induced Coalescence in Emulsions with High Volume Fractions of
           Dispersed Phase in the Presence of Surfactants
    • Authors: Meenakshi Mazumdar; Shantanu Roy
      Abstract: We report studies on the effect of volume fraction and surfactant concentration on the kinetics of destabilization of emulsions under the influence of gravity. Model oil-in-water emulsions, designed to mimic crude oil-water emulsions, were prepared with varying volume fractions of dispersed oil but nearly identical normalized initial drop size distributions. The gravity separation process was observed by periodically withdrawing samples and arresting further coalescence, and examining the droplet size distribution under the microscope. Experiments were carried out for three volume fractions of dispersed phase and two surfactant concentrations (0.4% and 1.6% by weight). At higher oil fractions (20%) and a lower surfactant concentration (0.4%), it was observed that although the rate of coalescence increased, the actual oil separation of was delayed and reduced rates of creaming were observed. At higher surfactant concentrations (1.6%), the dominant factor in suppressing destabilization is the rate of drop to interface coalescence. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-25T17:00:24.699423-05:
      DOI: 10.1002/aic.15803
       
  • Indirect Conduction in Gas-Solids Systems: Static vs. Dynamic Effects
    • Authors: Aaron M. Lattanzi; Christine M. Hrenya
      Abstract: Conductive mechanisms play an integral role in the transfer of heat through dense gas-solid systems. In particular, the conduction occurring through a thin layer of fluid between the solids (indirect) can become the primary mode for heat transfer within gas-solid systems. However, attempts to evaluate the effect of surface roughness and fluid lens thickness (theoretical inputs) on indirect conduction have been restricted to static, single-particle cases. By contrast, here we quantify these effects for dynamic, multi-particle systems using a non-dimensional, average heat transfer coefficient that is obtained via techniques commonly employed by classic kinetic theory. Analytical predictions for the impact of theoretical inputs on indirect conduction are compared to outputs from computational fluid dynamics – discrete element method simulations. The analytical predictions are in agreement with simulations and show that indirect conduction in static systems is most sensitive to surface roughness, while dynamic systems are sensitive to the fluid lens thickness. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-23T04:55:30.680415-05:
      DOI: 10.1002/aic.15802
       
  • Particle-Laden Liquid Jet Impingement On A Moving Substrate
    • Authors: Hatef Rahmani; Sheldon I. Green
      Abstract: The impingement of high speed jets on a moving surface was studied. The jet fluids were dilute suspensions of neutrally buoyant particles in water-glycerin solutions. At these low particle concentrations, the suspensions have Newtonian fluid viscosity. A variety of jet and surface velocities, solution properties, nozzle diameters, mean particle sizes, and volume fractions were studied. For each case the splash-deposition threshold was quantified. It was observed that for jets with very small particles, addition of solids to the jet enhances deposition and postpones splash relative to a particle-free water-glycerin solution with the same viscosity. In contrast, jets with larger particles in suspension were more prone to splash than single phase jets of the same viscosity. It is speculated that the change in character of the splash response for the jets with larger particles in suspension occurs when the particle diameter is comparable to the lamella thickness. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-23T04:55:29.523336-05:
      DOI: 10.1002/aic.15800
       
  • Mixing dynamics in bubbling fluidized beds
    • Authors: A. Bakshi; C. Altantzis, A.F. Ghoniem
      Abstract: Solids mixing affects thermal and concentration gradients in fluidized bed reactors and is, therefore, critical to their performance. Despite substantial effort over the past decades, understanding of solids mixing continues to be lacking because of technical limitations of diagnostics in large pilot and commercial-scale reactors. This study is focused on investigating mixing dynamics and their dependence on operating conditions using CFD simulations. Towards this end, fine-grid 3D simulations are conducted for the bubbling fluidization of three distinct Geldart B particles (1.15 mm LLDPE, 0.50 mm glass and 0.29 mm alumina) at superficial gas velocities U/Umf =2-4 in a pilot-scale 50 cm diameter bed. The Two-Fluid Model (TFM) is employed to describe the solids motion efficiently while bubbles are detected and tracked using MS3DATA. Detailed statistics of the flow-field in and around bubbles are computed and used to describe bubble-induced solids micromixing: solids upflow driven in the nose and wake regions while downflow along the bubble walls. Further, within these regions, the hydrodynamics are dependent only on particle and bubble characteristics, and relatively independent of the global operating conditions. Based on this finding, a predictive mechanistic, analytical model is developed which integrates bubble-induced micromixing contributions over their size and spatial distributions to describe the gross solids circulation within the fluidized bed. Finally, it is shown that solids mixing is affected adversely in the presence of gas bypass, or throughflow, particularly in the fluidization of heavier particles. This is because of inefficient gas solids contacting as 30-50% of the superficial gas flow escapes with 2-3× shorter residence time through the bed. This is one of the first large-scale studies where both the gas (bubble) and solids motion, and their interaction, are investigated in detail and the developed framework is useful for predicting solids mixing in large-scale reactors as well as for analyzing mixing dynamics in complex reactive particulate systems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-23T04:55:22.432144-05:
      DOI: 10.1002/aic.15801
       
  • Time-resolved ultrasonic spectroscopy for bubbles
    • Authors: Valentin Leroy; Anatoliy Strybulevych, Tomohisa Norisuye
      Abstract: We show that ultrasound can provide time-resolved measurements of the sizes distribution and the concentration of bubbles in a liquid. The potential of the technique is demonstrated by following disappearance of bubbles having an average radius of 20 µm with a 10 ms time resolution. We show that our technique can detect small concentrations of bubbles, with a large spectrum of accessible bubble radii (from 80 nm to 40 µm for a gas volume fraction of 10-5), and with a sub-millisecond time resolution. This new technique could be a valuable tool for investigating rapid processes such as nucleation or dissolution of bubbles. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-19T07:16:08.820515-05:
      DOI: 10.1002/aic.15799
       
  • A Green Process for Recovery of H2SO4 and Fe2O3 from FeSO4·7H2O by
           Modeling Phase Equilibrium of the Fe(П)‒SO42‒‒H+‒Cl‒ System
    • Authors: Yan Zhang; Zhibao Li, Yan Zeng, George P. Demopoulos
      Abstract: Ferrous sulfate heptahydrate FeSO4·7H2O is a major waste produced in titanium dioxide industry by the sulfate process and has caused heavy environmental problem. A new green process for the treatment of FeSO4·7H2O was proposed to make use of iron source and recycle sulfate source as H2SO4. It was found that by adding concentrated HCl to the FeSO4 solution, FeCl2·4H2O was crystallized out, which was subsequently calcined to produce Fe2O3 and HCl. Concentrated H2SO4 solution (about 65 wt%) was obtained by evaporating the FeCl2·4H2O-saturated filtrate. To facilitate the process development and design, the solubilities of FeCl2·4H2O in HCl, H2SO4, and HCl+H2SO4 solutions were measured and the experimental data were regressed with both the mixed-solvent electrolyte (MSE) model and the electrolyte NRTL model. On the basis of the prediction of the optimum conditions for the crystallization of FeCl2·4H2O, material balance of the new process was calculated. FeCl2·4H2O and Fe2O3 were obtained from a laboratory-scale test with about 70% recovery of ferrous source for a single cycle, indicating the feasibility of the process. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-19T06:15:32.86278-05:0
      DOI: 10.1002/aic.15795
       
  • Modeling of CO2 Equilibrium Solubility in a Novel
           1-diethylamino-2-Propanol Solvent
    • Authors: Helei Liu; Min Xiao, Xiao Luo, Hongxia Gao, Raphael Idem, Paitoon Tontiwachwuthikul, Zhiwu Liang
      Abstract: In this work, the equilibrium solubility of CO2 in a 1-diethylamino-2-propanol (1DEA2P) solution was determined as a function of 1DEA2P concentration (over the range of 1-2M), temperature (in the range of 298-333K), and CO2 partial pressure (in the range of 8-101kPa). These experimental results were used to fit the present correlation for K2 (Kent-Eisenberg model, Austgen model, and Li-Shen model). It was found that all of the models could represent the CO2 equilibrium solubility in 1DEA2P solution with ADDs for Kent-Eisenberg model, Austgen model, and Li-Shen model of 6.3%, 7.3% and 12.2%, respectively. A new K2 correlation model, the Liu-Helei model, was also developed to predict the CO2 equilibrium solubility in 1DEA2P solution with an excellent ADD of 3.4%. In addition, the heat of absorption of CO2 in 1DEA2P solution estimated by using the Gibbs-Helmholtz equation was found to be -45.7±3.7 kJ/mol. Information and guidelines about effectively using data for screened solvents is also provided based on the three absorption parameters: CO2 equilibrium solubility, second order reaction constant (k2), and CO2 absorption heat. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-19T05:50:38.187229-05:
      DOI: 10.1002/aic.15797
       
  • Effects of Protein Properties on Adsorption and Transport in
           Polymer-grafted Ion Exchangers: A Multiscale Modeling Study
    • Authors: Joseph E. Basconi; Giorgio Carta, Michael R. Shirts
      Abstract: We use multiscale modeling to study how the molecular properties of a protein affect its adsorption and transport in ion exchange (IEX) chromatography matrices with either open pores or charged polymers grafted into the pore structure. Coarse-grained molecular dynamics (MD) simulations of lysozyme, bovine serum albumin (BSA), and immunoglobulin (IgG) show that higher protein net charge leads to greater partitioning into the polymer-grafted pore space but slower diffusion there due to favorable electrostatic interactions, while larger size decreases both pore space partitioning and diffusion due to steric effects of the polymers. Mass transfer simulations based on the MD results show that the polymer-grafted systems can enhance the adsorption kinetics if pore space partitioning and diffusion are both sufficiently high. The simulations illustrate that to achieve fast adsorption kinetics, there is a tradeoff between favorable binding and rapid diffusion which largely depends on the charge and size of the protein. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-19T05:35:25.086719-05:
      DOI: 10.1002/aic.15798
       
  • MnOx Promotional Effects on Olefins Synthesis Directly from Syngas over
           Bimetallic Fe-MnOx/SiO2 Catalysts
    • Authors: Zhengpai Zhang; Weiwei Dai, Xin-Chao Xu, Jun Zhang, Bianfang Shi, Jing Xu, Weifeng Tu, Yi-Fan Han
      Abstract: The direct synthesis of lower olefins via the Fischer-Tropsch reaction (FTO) has been performed over a series of Fe-MnOx/SiO2 catalysts. The addition of MnOx could improve the dispersion of iron species, and promote the reduction of iron oxide during the activation and subsequent carburization. Moreover, the results of characterization demonstrated that MnOx could enhance the surface basicity of the catalysts due to electronic effects and promote the formation of iron carbides. For the first time, the intrinsic power-law kinetics for FTO was obtained for both Fe20/SiO2 and Fe20-Mn1/SiO2 catalysts. Kinetic parameters and structure characterizations indicated that MnOx could facilitate the CO dissociation on the catalyst surface, thus enhancing the adsorption strength and capacity of surface carbonaceous intermediates. The weak hydrogenation of carbonaceous species would boost the selectivities toward lower olefins. Finally, a plausible mechanism for FTO, involving the promotional effects of MnOx on Fe, has been proposed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-18T07:23:07.855747-05:
      DOI: 10.1002/aic.15796
       
  • Magnetohydrodynamics thin film fluid flow under the effect of
           thermophoresis and variable fluid properties
    • Authors: L Ali; I Saeed, T Gul, A Alshomrani, I Khan, K Aurangzeb
      Abstract: The thin film flow of fluid over a stretching sheet with variable fluid properties under the effect of thermophoresis has been investigated. A transverse magnetic field is also applied to the fluid flow in the presence of thermal radiation. The governing equations have been transformed through suitable similarity variables into nonlinear coupled differential equations with physical conditions. The solution of the coupled problem has been obtained by using the second alternative of OHAM (OHAM-2). The solution of the coupled problem through this new method and its fast convergence is mainly focused in this work. The effect of physical parameters appears in the problem are shown graphically and discussed. Finally, the obtained results are compared with a numerical (ND-Solve) method to authenticate the code of the OHAM-2. The physical and numerical agreement of these two methods has been shown. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-18T07:05:26.299711-05:
      DOI: 10.1002/aic.15794
       
  • Simulation of Deformable Preformed Particle Gel Propagation in Porous
           Media
    • Authors: Jing Wang; Hui-qing Liu, Hong-ling Zhang, Kamy Sepehrnoori
      Abstract: Preformed particle gel (PPG) treatment is a proven cost-effective method for improving oil recovery. Although PPG system has a suspension-like property, it has different propagation rules from the rigid particle suspension in porous media because of its good deformation property. In this study, an advanced phenomenological model of PPG propagation in porous media is presented. The model includes both PPG plugging and restarting behaviors. Log-normal and normal distribution functions have been introduced in this model to calculate the PPG plugging probability. Power-law equation is used to calculate the PPG restarting rate. This method can represent the commensurate relation between PPG and throat size. Then, the equations are solved numerically, using an explicit finite-difference formulation in conjunction with a fourth-order Runge-Kutta method. The results match favorably with several laboratory experiments. Finally, the propagation rules and sensitivity analysis of PPG size, permeability and injection rate to propagation rules, and permeability reduction are performed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-16T04:40:43.104119-05:
      DOI: 10.1002/aic.15793
       
  • NMR Spectroscopic Study of Chemical Equilibria in Solutions of
           Formaldehyde, Water, and Butynediol
    • Authors: Jürgen Berje; Jens Baldamus, Jakob Burger, Hans Hasse
      Abstract: Liquid mixtures of formaldehyde, water, and butynediol are complex reacting multicomponent systems in which formaldehyde forms oligomers both with water and butynediol. 1H - and 13C -NMR spectra of these mixtures are elucidated. The species distribution of the oligomers is quantitatively determined by 13C -NMR spectroscopy. The measurements cover temperatures from 293 K to 366 K, overall formaldehyde mass fractions from 0.10gg-1 to 0.27gg-1, and overall butynediol mass fractions from 0.05gg-1 to 0.50gg-1. A mole fraction-based and an activity-based model of the chemical equilibrium in the studied system are developed and chemical equilibrium constants are reported. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:46:44.52981-05:0
      DOI: 10.1002/aic.15788
       
  • Distributed Output-Feedback Fault Detection and Isolation of Cascade
           Process Networks
    • Authors: Xunyuan Yin; Jinfeng Liu
      Abstract: In this work, we consider distributed output-feedback fault detection and isolation (FDI) of nonlinear cascade process networks that can be divided into subsystems. Based on the assumption that an exponentially convergent estimator exists for each subsystem, a distributed state estimation system is developed. In the distributed state estimation system, a compensator is designed for each subsystem to compensate for subsystem interaction and the estimators for subsystems communicate to exchange information. It is shown that when there is no fault, the estimation error of the distributed estimation system converges to zero in the absence of system disturbances and measurement noise. For each subsystem, a state predictor is also designed to provide subsystem state predictions. A residual generator is designed for each subsystem based on subsystem state estimates given by the distributed state estimation system and subsystem state predictions given by the predictor. A subsystem residual generator generates two residual sequences, which act as references for FDI. A distributed FDI mechanism is proposed based on residuals. The proposed approach is able to handle both actuator faults and sensor faults by evaluating the residual signals. A chemical process example is introduced to demonstrate the effectiveness of the distributed FDI mechanism. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:46:39.096694-05:
      DOI: 10.1002/aic.15791
       
  • Accurate thermodynamic modeling of ionic liquids/metal salt mixtures:
           Application to carbon monoxide reactive absorption
    • Authors: Gabriel Zarca; Inmaculada Ortiz, Ane Urtiaga, Fèlix Llovell
      Abstract: For the first time, a theoretical semi-predictive approach based on the soft-SAFT equation of state is presented to model the complexation reaction between carbon monoxide (CO) in a combined ionic liquid (IL) plus a copper(I) metallic salt media in terms of the gas solubility as a function of temperature, pressure and composition. Two different degrees of molecular approximation are tested. In the first approach, the IL-metal salt mixture is treated as a single compound whose parameters are modified according to the concentration of the metallic salt. In the second approach, both compounds are treated as independent species, enhancing the predictive capability of the model. The complexation between CO molecules and the metal salt is reproduced by adding specific cross-association interaction sites that simulate the reaction. The density of the doped IL and the CO solubility are described in quantitative agreement with the experimental data at different operating conditions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:46:30.025594-05:
      DOI: 10.1002/aic.15790
       
  • Capillary Driven Flow in Wettability altered Microchannel
    • Authors: Ayantika Sett; Uzma Bano, Debasish Sarkar, Arijit Mitra, Siddhartha Das, Swagata Dasgupta, Sunando DasGupta
      Abstract: The capillary driven flow of water inside a microchannel with altered wettabilities is experimentally investigated and modelled theoretically. The surfaces of the PDMS made microchannel are exposed to oxygen plasma, rendering the surfaces increasingly hydrophilic, which provides the driving force for the flow. The plasma treated surfaces are characterized using topography and phase imaging of AFM scanning, as well as nano-indentation, to correlate the distinct structural changes to the hydrodynamic profiles of the advancing meniscus. The experimental results are further analyzed using a newly-proposed slip velocity model. The aim is to obtain a qualitative relationship between the surface properties and the flow parameters, namely the advancing meniscus velocity and pressure drop inside the channel. The insights are of fundamental importance in diverse fields, such as enhanced oil recovery, microfluidic devices, cell separation and pathology. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:46:16.652557-05:
      DOI: 10.1002/aic.15787
       
  • A Data-Driven Multistage Adaptive Robust Optimization Framework for
           Planning and Scheduling under Uncertainty
    • Authors: Chao Ning; Fengqi You
      Abstract: We propose a novel data-driven approach for optimization under uncertainty based on multistage adaptive robust optimization (ARO) and nonparametric kernel density M-estimation. Different from conventional robust optimization methods, the proposed framework incorporates distributional information to avoid over-conservatism. Robust kernel density estimation with Hampel loss function is employed to extract probability distributions from uncertainty data via a kernelized iteratively re-weighted least squares algorithm. A data-driven uncertainty set is proposed, where bounds of uncertain parameters are defined by quantile functions, in order to organically integrate the multistage ARO framework with uncertainty data. Based on this uncertainty set, we further develop an exact robust counterpart in its general form for solving the resulting data-driven multistage ARO problem. To illustrate the applicability of the proposed framework, two typical applications in process operations are presented: The first one is on strategic planning of process networks, and the other one on short-term scheduling of multipurpose batch processes. The proposed approach returns 23.9% higher net present value and 31.5% more profits than the conventional robust optimization method in planning and scheduling applications, respectively. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:46:05.143171-05:
      DOI: 10.1002/aic.15792
       
  • PEI-grafted Membranes for Simultaneously Adsorbing Heavy Metal Ions and
           Rejecting Suspended Particles in Wastewater
    • Authors: Xuehua Ruan; Yan Xu, Xuhang Liao, Gaohong He, Xiaoming Yan, Yan Dai, Ning Zhang, Lin Du
      Abstract: Heavy metal ions (HMIs) in wastewater can be removed by polyethyleneimine (PEI) adsorption, however, it is difficult to recycle PEI macromolecules from their mixture with suspended particles in wastewater. A novel HMIs adsorption technique with renewable PEI-grafted porous membranes was developed. PEI molecules were dispersed with high specific area and structured morphology, which allowed HMIs and suspended particles to be retained separately at different locations of the membrane, with the former adsorbed in matrix and the latter rejected on surface. The membranes with the optimized PEI loading ratio of 30wt% behaved excellently with microsphere rejection and Co(II) adsorption reaching 98.5% and 51.0mg/g, respectively. They successfully decreased Co(II) concentration from 3.0mg/L to the allowable discharge standard (0.5mg/L), even with an enhanced flux of 6200L/m2/h at 0.12MPa under the cyclic tests. Overall, PEI-grafted membrane adsorption is highly efficient for removing HMIs and suspended particles simultaneously from wastewater. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:45:47.841511-05:
      DOI: 10.1002/aic.15789
       
  • A Cobalt Metal-Organic Framework with Small Pore Size for Adsorptive
           Separation of CO2 over N2 and CH4
    • Authors: Bohan Shan; Jiuhao Yu, Mitchell R. Armstrong, Dingke Wang, Zhenfei Cheng, Jichang Liu, Bin Mu
      Abstract: In this study, a new cobalt-based metal-organic framework (MOF), [CoII6(μ3-OH)2(ipa)5(C3O2)(DMF)2] (CoIPA) was synthesized. The crystal structure analysis shows that CoIPA is constructed by Co6(μ3-OH)2 units linked by isophthalic acid forming a sxb topology and it possesses a small pore size of about 4 Å. The new MOF has been characterized using multiple experimental methods. Monte Carlo and Molecular Dynamic simulations were employed to investigate adsorption equilibrium and kinetics in terms of capacity and diffusivity of CO2, N2, and CH4 on CoIPA. The gas adsorption isotherms collected experimentally were used to verify the simulation results. The activated CoIPA sample exhibits great gas separation ability at ambient conditions for CO2/N2 and CO2/CH4 with selectivity of around 61.4 and 11.7, respectively. The calculated self-diffusion coefficients show a strong direction dependent diffusion behavior of target molecules. This high adsorption selectivity for both CO2/N2 and CO2/CH4 makes CoIPA a potential candidate for adsorptive CO2 separation. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-11T18:35:32.961171-05:
      DOI: 10.1002/aic.15786
       
  • Modeling and Process Simulation of Hollow Fiber Membrane Reactor Systems
           for Propane Dehydrogenation
    • Authors: Seung-Won Choi; Jason S. Moore, Yujun Liu, Ravindra S. Dixit, John G. Pendergast, David S. Sholl, Sankar Nair
      Abstract: We report a detailed modeling analysis of membrane reactor systems for propane dehydrogenation (PDH) by integrating a two-dimensional (2D) non-isothermal model of a packed bed membrane reactor (PBMR) with ASPEN process simulations for the overall PDH plant including downstream separations processes. PBMRs based upon ceramic hollow fiber membranes - with catalyst placement on the shell side - are found to be a viable route, whereas conventional tubular membranes are prohibitively expensive. The overall impact of the PBMR on the PDH plant (e.g., required dimensions, catalyst amount, overall energy use in reaction and downstream separation) is determined. Large savings in overall energy use and catalyst amounts can be achieved with an appropriate configuration of PBMR stages and optimal sweep/feed ratio. Overall, this work determines a viable design of a membrane reactor-based PDH plant and shows the potential for miniaturized hollow-fiber membrane reactors to achieve substantial savings. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-09T18:35:50.248779-05:
      DOI: 10.1002/aic.15785
       
  • Predicting Solvent Effects on the 1-dodecene Hydroformylation Reaction
           Equilibrium
    • Authors: Max Lemberg; Martin Gerlach, Emilija Kohls, Christof Hamel, Andreas Seidel-Morgenstern, Matthias Stein, Gabriele Sadowski
      Abstract: This work investigates solvent effects on the reaction equilibrium of the 1-dodecene hydroformylation in a decane/N,N-dimethylformamide solvent system. The reaction was performed at different decane/N,N-dimethylformamide ratios and at temperatures between 368 K and 388 K. The equilibrium concentrations of all reactants and products were determined experimentally. The enthalpy and Gibbs energy of this reaction at the ideal-gas standard state were determined by quantum-chemical calculations in good agreement with literature data. Moreover, quantum-chemically calculated standard Gibbs energies of reaction at infinite dilution in liquid decane/DMF-solvent mixtures allowed a qualitative prediction of the solvent effect on the equilibrium concentrations.Based on the standard Gibbs energy of reaction at the ideal-gas standard state and on fugacity coefficients calculated using the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT), the equilibrium concentrations of reactants and products for the 1-dodecene hydroformylation performed in decane/N,N-dimethylformamide mixtures of different compositions could be predicted in very good agreement with experimental data. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-06T03:38:32.387632-05:
      DOI: 10.1002/aic.15782
       
  • A critical review of statistical calibration/prediction models handling
           data inconsistency and model inadequacy
    • Authors: Pascal Pernot; Fabien Cailliez
      Abstract: Inference of physical parameters from reference data is a well studied problem with many intricacies (inconsistent sets of data due to experimental systematic errors; approximate physical models…). The complexity is further increased when the inferred parameters are used to make predictions – virtual measurements – because parameter uncertainty has to be estimated in addition to parameters best value. The literature is rich in statistical models for the calibration/prediction problem, each having benefits and limitations. We review and evaluate standard and state-of-the-art statistical models in a common bayesian framework, and test them on synthetic and real datasets of temperature-dependent viscosity for the calibration of the Lennard-Jones parameters of a Chapman-Enskog model. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-06T03:34:57.614616-05:
      DOI: 10.1002/aic.15781
       
  • A Multi-Continuum Approach for the Problem of Filtration of Oily-Water
           Systems across Thin Flat Membranes: I. the Framework
    • Authors: Amgad Salama; Mohamed Zoubeik, Amr Henni
      Abstract: In this work, a multi-continuum model is built to estimate the permeate flux of an oily water system across a thin flat membrane in cross filtration methodology. Several continua are constructed to represent droplet and pore size distribution of both the dispersed oil phase and the porous membrane, respectively. The possible permeation of the oil phase has been divided into three criteria. In the first criterion, oil droplets of a given size range may permeate through a given size range of the porous membrane, in the second criterion, oil droplets of another size range may be rejected through another pore size range, and in the third criterion, oil droplets may break apart leaving a tail inside the pore space, which will eventually permeate, and the rest will sweep off due to shear stress. These protocols identify the methodology of the proposed multi-continuum approach, which is introduced in this first part. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-06T03:29:45.069554-05:
      DOI: 10.1002/aic.15784
       
  • Improving Docosahexaenoic Acid Production by Schizochytrium sp. using a
           Newly Designed High-Oxygen-Supply Bioreactor
    • Authors: Dong-Sheng Guo; Xiao-Jun Ji, Lu-Jing Ren, Gan-Lu Li, He Huang
      Abstract: A sufficiently high oxygen supply is crucial for high-cell-density cultivation of aerobic microorganisms, including Schizochytrium sp. We therefore designed a novel bioreactor enabling high-level oxygen supply, and its relevant process parameters and fermentation-stage characteristics were investigated. The real-time changes of pH and non-oil biomass were monitored as proxies for the consumption of nitrogen and lipid accumulation status, which was firstly applied to divided fermentation process with 3 stages. The experimental results showed that the biomass in this porous-membrane-impeller bioreactor was higher than in conventional bioreactor, while docosahexaenoic acid (DHA) percentage in total lipids was lower than in conventional bioreactor. We subsequently implemented a multi-stage control strategy for the porous-membrane-impeller bioreactor, and the maximum biomass, DHA concentration, DHA percentage in biomass and DHA productivity reached 151.0 g/L, 44.3 g/L, 29.33%, 369.08 mg/(L·h), respectively. This study thus provides a highly efficient and economic bioreactor for the production of DHA by Schizochytrium sp. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-06T03:24:35.104955-05:
      DOI: 10.1002/aic.15783
       
  • Function and Effect of the Inner Vortex on the Performance of Cyclone
           Separators
    • Authors: Bo Wang; Binbin Pei, Delong Xu, He Liu, Yunchao Jiang, Yanxin Chen
      Abstract: The inner vortex plays a key role in the performance of cyclone separators. In order to explore the function and effect of the inner vortex in cyclone separators, a series of metal rods and metal blades are inserted in the typical Lapple cyclone separator to reduce the intensity of the inner vortex. Firstly, the changes in general performance of cyclones are measured by experimental methods after insertion of the metal rods and metal blades. The flow field and particle motion are then simulated, respectively, by means of a Reynolds stress model (RSM) and a Lagrangian particle tracking (LPT) model. The results show that when the length of the metal blades is less than the boundary between the inner and outer vortexes, that is, the outer vortex remains unchanged and the inner vortex is destroyed partly, the separation efficiency remains constant and the pressure drop significantly decreases. When the length of the metal blades exceeds the boundary, the inner vortex is completely destroyed, and the outer vortex is significantly damaged, which results in sharp decrease of both the separation efficiency and pressure drop. The results indicate that the inner vortex has a notable effect on the pressure drop and virtually none on the separation efficiency. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-04T17:20:49.849111-05:
      DOI: 10.1002/aic.15780
       
  • Impact of Osmotic Agent on the Transport of Components using forward
           Osmosis to Separate Ethanol from Aqueous Solutions
    • Authors: Alan Ambrosi; Guilherme Lopes Correa, Natiéli Souza de Vargas, Lucas Martim Gabe, Nilo Sérgio Medeiros Cardozo, Isabel Cristina Tessaro
      Abstract: The separation of low molecular weight organic compounds such as the ethanol from aqueous solutions represents an important area to be investigated and increment the range of applications of forward osmosis. This investigation assesses the effects of using different draw solutes for ethanol separation from dilute aqueous solutions. The influence of glucose, sucrose, sodium chloride and magnesium chloride was evaluated in terms of total permeate, reverse solute and ethanol fluxes. Inorganic solutes promoted higher total permeate and ethanol fluxes than the organic solutes (2.5 and 1.5 times higher in average, respectively) for the same molar concentration, while presenting only 1.1 times higher reverse solute fluxes. Despite the lower ethanol flux promoted by the organic draw solutes, these osmotic agents promoted higher concentration of ethanol in the total permeate flux, suggesting that they can also be alternatives for specific processes. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-04T17:20:41.151399-05:
      DOI: 10.1002/aic.15779
       
  • Gas permeation properties for organosilica membranes with different Si/C
           ratios and evaluation of microporous structures
    • Authors: Masakoto Kanezashi; Yuri Yoneda, Hiroki Nagasawa, Kazuki Yamamoto, Joji Ohshita, Toshinori Tsuru
      Abstract: Organosilica membranes were fabricated using bridged organoalkoxysilanes (bis(triethoxysilyl)methane (BTESM), bis(triethoxysilyl)ethane (BTESE), bis(triethoxysilyl)propane (BTESP), bis(trimethoxysilyl)hexane (BTMSH), bis(triethoxysilyl)benzene (BTESB), and bis(triethoxysilyl)octane (BTESO)) to produce highly permeable molecular sieving membranes. The effect of the organoalkoxysilanes on network pore size and microporous structure was evaluated by examining the molecular size and temperature dependence of gas permeance across a wide range of temperatures. Organosilica membranes showed H2/N2 and H2/CH4 permeance ratios that ranged from 10-150, corresponding to network pore size, and both H2 selectivity decreased with an increase in the carbon number between 2 Si atoms. Organosilica membranes showed activated diffusion for He and H2, and a slope of temperature dependence that increased approximate to the increase in the carbon number between 2 Si atoms. The relationship between activation energy and He/H2 permeance ratio for SiO2 and organosilica membranes suggested that the molecular sieving can dominate He and H2 permeation properties via the rigid microporous structure, which was constructed by BTESM and BTESE. With increased in the carbon concentration in silica, polymer chain vibration in organic bridges, which is a kind of solution/diffusion mechanism, can dominate the permeation properties. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-04T17:15:48.909427-05:
      DOI: 10.1002/aic.15778
       
  • CO2 Capture in a Multistage CFB: Part II: Riser with Multiple Cooling
           Stages
    • Authors: Sutthichai Boonprasop; Dimitri Gidaspow, Benjapon Chalermsinsuwan, Pornpote Piumsomboon
      Abstract: A 1 m in diameter and 3.55 m tall fluidized bed riser internally with water tubes, which required 6 equilibrium stage of riser-sorber for capturing about 95 percent of CO2 emitted from a coal power plant, were designed to replace the multi single risers. At the optimum operating condition, the temperature of the cooling tubes in the bottom, the middle and the top of the riser were kept constant values at 50 40 and 30°C, respectively. The hot water (57°C) from lowest exchanger section can be used to pre-heat the spent sorbent for the regeneration in a downer. The rest of the heat for the regenertion is obtained from the stack gas (100 – 130°C). This new concept promises to reduce the energy consumption for CO2 removal from flue gas. The only energy requirement is for pumping fluid and fluidizing particles in the bed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-04T17:00:39.760301-05:
      DOI: 10.1002/aic.15777
       
  • CO2 Capture in a Multistage CFB: Part I: Number of Stages
    • Authors: Sutthichai Boonprasop; Dimitri Gidaspow, Benjapon Chalermsinsuwan, Pornpote Piumsomboon
      Abstract: The most common technology for post-combustion of CO2 capture is the amine solvent scrubber. The energy consumption for capturing CO2 from flue gases using amine solvent technology is 15 to 30% of the power plant electricity production. Hence, there is a need to develop more efficient methods of removing CO2. A circulating fluidized bed using sodium or potassium carbonates is potentially such a process, since their high decomposition pressures allow regeneration at low temperatures using waste heat rather than steam from the power plant. But equilibrium data for the sorbents require the use of several cooled stages to achieve high CO2 conversions. Here a method of computing such a number of stages for a given CO2 conversion was developed using multiphase computational fluid dynamics. It was found that it required 6 equilibrium stages to remove 96 percent of CO2 with the initial mole fraction of 0.15 in a sorption riser. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-04T17:00:32.904769-05:
      DOI: 10.1002/aic.15776
       
  • Influence of Adhesion on Random Loose Packings of Binary Micro-Particle
           Mixtures
    • Authors: Wenwei Liu; Sheng Chen, Shuiqing Li
      Abstract: Binary adhesive packings of microspheres with certain size ratios are investigated via a 3D discrete-element method specially developed with adhesive contact mechanics. We found a novel phenomenon that the packing fraction of the binary adhesive mixtures decreases monotonically with the increase of the amount of small components. It was further divulged that this behavior results from the competition between a geometrical filling effect and an adhesion effect. The positive geometrical filling effect only depends on the size ratio, while a dimensionless adhesion parameter Ad is employed to characterize the negative adhesion effect, which comes to its maximum at Ad≈10. Structural properties, including contact network, partial coordination number, radial distribution function and angular distribution function, are analyzed in order to give a better understanding of such adhesive binary packings. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-02T10:59:12.694821-05:
      DOI: 10.1002/aic.15775
       
  • An experimental study of the flow of non-spherical grains in a rotating
           cylinder
    • Authors: Sandip Mandal; D. V. Khakhar
      Abstract: The effect of particle aspect ratio on the rheology of the flow of granular materials is studied experimentally in a quasi-two-dimensional rotating cylinder, using two varieties of prolate spheroidal grains with different aspect ratios. Image analysis of high speed videos is employed to obtain the flow profiles near the centre of the cylinder. The dynamic angle of repose and apparent viscosity in the medium show significant increase with increasing aspect ratio. The mean velocity, root mean square velocity and shear rate profiles are qualitatively similar for non-spherical and spherical particles, however, their magnitudes increase with increasing aspect ratio. A simple scaling is shown to predict the maximum thickness of the flowing layer for all the particles. The predictions of a model for the flow match with the measured mean velocity profiles and layer thickness. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-30T18:40:25.773605-05:
      DOI: 10.1002/aic.15772
       
  • Catalytic ozonation of cinnamaldehyde to benzaldehyde over CaO:
           Experiments and Intrinsic kinetics
    • Authors: Jianfeng Wu; Tongming Su, Yuexiu Jiang, Xinling Xie, Zuzeng Qin, Hongbing Ji
      Abstract: The preparation, characterization of CaO and its application in the catalytic ozonation of cinnamaldehyde to benzaldehyde were studied. The calcination temperature greatly affected the physicochemical properties of CaO, and the CaO calcined at 900°C exhibited the optimal ozone utilization efficiency. When using 0.20 g CaO calcined at 900°C, 750 mL·min−1 oxygen flow rate for generating O3, and reacted at 0°C for 210 min, the cinnamaldehyde conversion reached 97.77%, as well as the benzaldehyde yield was 59.51%. And the cinnamaldehyde conversion in a catalytic ozonation on CaO catalyst maintained above 90% for four used cycles, which exhibited reasonable catalyst stability. The electron donating process of surface O2- on the catalyst is the key to improve the benzaldehyde yield, and based on the intrinsic kinetic study, the Eley-Rideal kinetic model with cinnamaldehyde being adsorbed was the appropriate model for the catalytic ozonation of cinnamaldehyde on CaO. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-30T18:40:17.85115-05:0
      DOI: 10.1002/aic.15773
       
  • Numerical Simulation of Solvent and Water Assisted Electrical Heating of
           Oil Sands Including Aquathermolysis and Thermal Cracking Reactions
    • Authors: Hassan Hassanzadeh; Moosa Rabiei Faradonbeh, Thomas Harding
      Abstract: Simulations of bitumen recovery using solvent- and water-assisted electrical heating of oil sands are presented to evaluate the process and to study gas generation. Aquathermolysis and thermal cracking and dissolution of acid-gases in water are included. Steam-assisted gravity drainage (SAGD) is also simulated for comparison. Results show that gas generation negatively impacts SAGD. However, in electrical heating dissolution of gases into solvent weakens their negative impact. Results indicate that SAGD generates a larger gas volume than electrical heating. In both processes, methane is found to be the major species in the produced gas and H2S concentration can reach high values. While the effect of acid-gas solubility in water on oil recovery is not evident its effect on generated gas volume is significant. Simulation results demonstrate that electrical heating is more energy efficient than SAGD. These results find application in design of experiments and pilot and field-scale implementation of the process. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-30T18:40:15.922771-05:
      DOI: 10.1002/aic.15774
       
  • A Mathematical Model for Optimal Compression Costs in the Hydrogen
           Networks for the Petroleum Refineries
    • Authors: Anoop Jagannath; Ali Almansoori
      Abstract: Hydrogen network design is an important step in hydrogen management of a petroleum refinery that manages the hydrogen distribution and consumption in a cost-effective manner. While most works in this area have primarily focused on minimization of fresh hydrogen requirement and hydrogen purification aspects, very few works have dealt the issue of compression costs in hydrogen network designs. This work proposes a new mathematical model for synthesizing a hydrogen network with minimum compression costs. In contrast to the existing literature, this model uses stream-dependent properties and realistic compressor cost correlations to determine the compression duty and costs respectively. Tests on literature examples show that our model is flexible and gives reasonably favorable solutions than the previous models. Furthermore, the usefulness of understanding the trade-offs between the number of compressors and compression duty and the importance of using stream-dependent conditions in estimating compression costs are also highlighted in this work This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-27T19:07:52.625742-05:
      DOI: 10.1002/aic.15771
       
  • Direct Non-Oxidative Conversion of Methane to Hydrogen and Higher
           Hydrocarbons by Dielectric Barrier Discharge Plasma with Plasma Catalysis
           Promoters
    • Authors: Elijah Chrimba; Kui Zhang, Canan Kazak, Galip Akay
      Abstract: Direct non-oxidative conversion of methane to hydrogen and hydrocarbons were achieved at atmospheric pressure and 120°C using non-thermal plasma sustained by Plasma Catalysis Promoters (PCPs). Reactors had two different electrode configurations. Methane conversion correlated well with the Specific Energy Density (SED). Methane conversion was independent of plasma power, flow rate, electrode configuration or the type of PCPs. Hydrogen selectivity (ca. 60%) was dependent significantly on PCP and electrode configuration. The ethane/ethylene molar ratio increased from 0 to 0.15 with increasing SED. When the SED value was below ca. 100 kJ/L, ethylene was the only C2 hydrocarbon. These results are similar to the recently reported non-oxidative catalytic methane conversion at ca. 1000°C. Therefore, these results represents Process Intensification in methane conversion. PCPs underwent structural and chemical changes but their performance are not affected during an 80-hour experimental period. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-25T10:45:38.573336-05:
      DOI: 10.1002/aic.15769
       
  • Validating Granular Segregation Rate Models
    • Authors: Siying Liu; J.J. McCarthy
      PubDate: 2017-04-25T10:40:28.721918-05:
      DOI: 10.1002/aic.15770
       
  • Facile Synthesis of Pd@Pt Octahedra Supported on Carbon for
           Electrocatalytic Applications
    • Authors: Shengnan Yu; Lei Zhang, Hao Dong, Jinlong Gong
      Abstract: Due to the scarce nature of Pt, it is highly desirable to construct core-shell structures with ultrathin Pt shells while maintaining its high electrocatalytic activity. However, it is necessary to preferentially synthesize a core with a specific structure before further formation of core-shell catalysts with specific morphologies. This prerequisite greatly increases the complexity of the synthesis process. This paper describes a synthetic method of core-shell Pd@Pt octahedra catalysts from Pd nanocubes, truncated nanocubes or truncated octahedra. The formation of octahedral core-shell structures involves two key factors: (1) the oxidative etching process of Pd atoms at the corner sites; (2) the different reduction rates between Pt and Pd precursors. This mechanism can be extended to synthesize carbon-supported sub-8 nm Pd@Pt octahedra from commercial Pd/C catalysts. The derived carbon-supported Pd@Pt octahedra catalysts performed comparable activity and durability for methanol oxidation reaction with state-of-art PtRu/C catalysts. This synthetic method provides an innovative path for large-scale production of well-controlled catalysts. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-21T11:10:20.382368-05:
      DOI: 10.1002/aic.15763
       
  • Selective removal of 1,2-propanediol and 1,2-butanediol from bio-ethylene
           glycol by catalytic reaction
    • Authors: Shuo Ai; Mingyuan Zheng, Yu Jiang, Xiaofeng Yang, Xinsheng Li, Jifeng Pang, Joby Sebastian, Weizhen Li, Aiqin Wang, Xiaodong Wang, Tao Zhang
      Abstract: Ethylene glycol (EG), synthesized from biomass, frequently contains refractory 1,2-propanediol (PDO) and 1,2-butanediol (BDO). Selective removal of PDO and BDO was realized herein by catalytic dehydration to form volatile aldehydes, ketones, and acetals. Various acidic and basic catalysts were screened under a range of conditions for the conversion of a mixture containing 73 wt% EG, 20 wt% PDO and 7 wt% BDO. Over H-Beta 26 zeolite, the most selective catalyst among tested, PDO and BDO conversions reached 99.1% and 99.3%, respectively after 4 h reaction at 453 K, with separation factors over 2. The activation energies for EG, PDO, and BDO dehydration were ca. 99.3, 69.9, and 54.0 kJ/mol, respectively, accounting for the high reactivity of PDO and BDO. The dehydration largely proceeded in the micropores of H-Beta and depended on the number of strong Brønsted acid sites, but excessively strong acid sites enhanced the polymerization of EG. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-21T11:10:18.434181-05:
      DOI: 10.1002/aic.15764
       
  • Numerical prediction of a Nusselt number equation for stirred tanks with
           helical coils
    • Authors: R. P. Jaimes; J. R. Nunhez
      Abstract: A methodology to obtain a Nusselt correlation for stirred tank reactors is presented. The novelty of the approach is the use of a validated computational model to obtain the heat transfer coefficients. The advantages of this new approach are many, including the possibility of testing different heat transfer configurations to obtain their Nusselt correlation without performing experimental runs. Physical phenomena involved was represented both qualitatively and quantitatively. The classical experimental work of Oldshue and Gretton (1954) illustrates the procedure. A sufficient number of virtual points in the whole range of the Reynolds number should be obtained. Results strongly depend on mesh refinement in the boundary layer, so a procedure is suggested to guarantee heat transfer coefficients are accurately estimated. The final Nusselt correlation was compared against all the 107 experimental points of the work by Oldshue and Gretton [1], and an average deviation on the results of 10.7%. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-21T11:07:44.021629-05:
      DOI: 10.1002/aic.15765
       
  • Growth and Breakup of a Wet Agglomerate in a Dry Gas-Solid Fluidized Bed
    • Authors: C. M. Boyce; A. Ozel, J. Kolehmainen, C.A. McKnight, M. Wormsbecker, S. Sundaresan
      Abstract: Using CFD-DEM simulations, a wet agglomerate of particles was placed in a void region of a dry vigorously fluidized bed to understand how wet agglomerates grow or breakup and how liquid spreads when agglomerates interact with dry fluidized particles. In the CFD-DEM model, cohesive and viscous forces arising from liquid bridges between particles were modeled, as well as a finite rate of liquid bridge filling. The liquid properties were varied between different simulations to vary Bond number (surface tension forces/gravitational forces) and Capillary number (viscous forces/surface tension forces) in the system. Resulting agglomerate behavior was divided into regimes of (i) the agglomerate breaking up, (ii) the agglomerate retaining its initial form, but not growing and (iii) the agglomerate retaining its initial form and growing. Regimes were mapped based on Bo and Ca. Implications of agglomerate behavior on spreading of liquid to initially dry particles were investigated.This paper identifies a new way to map agglomerate growth and breakup behavior based on Bo and Ca. In modeling both liquid forces and a finite rate of liquid transfer, it identifies the complex influence viscosity has on agglomeration by strengthening liquid bridges while slowing their formation. Viewing Ca as the ratio of bridge formation time to particle collision and separation time capture why agglomerates with high Ca struggle to grow. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T11:17:18.714829-05:
      DOI: 10.1002/aic.15761
       
  • Consensus Algorithm-Based Approach to Fundamental Modeling of Water Pipe
           Networks
    • Authors: Shin Je Lee; Jingbo Wu, Jung Chul Suh, Gibaek Lee, Frank Allgöwer, Jong Min Lee
      Abstract: Modeling the flow dynamics of leaks in water pipe networks is an extremely difficult problem due to the complex entangled network structure and hydraulic phenomenon. We propose a mathematical model for leak dynamics in water pipe networks based on consensus algorithm and water hammer theory. The resulting model is a simple and linearly interconnected system even though the dynamics of water pipe networks has considerable complexity. The model is then validated using experimental data obtained from real pipe network. A comparative study demonstrates the proposed model can describe the real system with high qualitative and quantitative accuracy and it can be used to develop model-based leak detection and location algorithm based on state estimation. To show applicability of the proposed model, we apply cooperative estimation to the developed model. The results demonstrate the consensus based pipe model can be potentially used for leak detection and location with state estimation. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T11:17:12.335023-05:
      DOI: 10.1002/aic.15760
       
  • Validation of a CFD model of an Orbiting Culture Dish with PIV and
           Analytical Solutions
    • Authors: Jonathan Michael D Thomas; Mostafa Shakeri, Amlan Chakraborty, M. Keith Sharp, R. Eric Berson
      Abstract: Particle image velocimetry (PIV) and an extended solution of Stokes' second problem were used to validate a computational fluid dynamics (CFD) model of flow in an orbiting dish. Velocity vector components throughout one complete orbit differed between CFD and PIV by less than 5%. Computational velocity magnitudes averaged over the interior 20% radius, the region where the analytical solution is most applicable, were 0.3% higher than the analytical values, while the experimental values in the same region were 2.4% higher. Velocity profiles in the center of the dish across normalized heights that most influence wall shear stress varied on average by ∼-0.00046 for the normalized radial component and by ∼0.0038 for the normalized tangential component compared to the analytical solution. These results represent the most comprehensive validation to date for computational models of the orbiting dish system. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T11:06:01.122218-05:
      DOI: 10.1002/aic.15762
       
  • Hydrophobic Surface Modification of FMSS and its Application as Effective
           Sorbents for Oil Spill Clean-ups and Recovery
    • Authors: Oluwasola Oribayo; Qinmin Pan, Xianshe Feng, Garry L Rempel
      Abstract: Superhydrophobic sponge-like materials are attracting more attention in recent years as potential sorbent materials for oil-spill clean-up. In this work, we report the incorporation of hydrophobic structural features into a superhydrophilic pristine formaldehyde-melamine-sodium bisulfite copolymer Sponge (FMSS) by N-acylation with a fatty acid derivative, for use as an oil sorbent in oil-spill clean-ups. This resulted in our ability to transform the surface properties of the sponge skeleton to superhydrophobic with a contact angle of 143°. The acylated formaldehyde-melamine-sodium bisulfite copolymer Sponge (a-FMSS) was shown to retain the interconnected porous structure, and was characterized with microscopic and spectroscopic analyses. Sorption experiments with engine oil and chloroform showed that a-FMSS had a very high oil sorption capacity (amounting to 99 and 168.2 times its own weight respectively) than commercial nonwoven Polypropylene sorbent. In this view, a-FMSS is considered to be a promising oil sorbent for potential applications in large-scale oil-spill clean-ups. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T04:03:14.546982-05:
      DOI: 10.1002/aic.15767
       
  • Linking particle properties to dense suspension extrusion flow
           characteristics using discrete element simulations
    • Authors: Christopher Ness; Michele Marigo, Paul McGuire, Han Xu, Hugh Stitt, Jin Y. Ooi, Jin Sun
      Abstract: Extrusion is a widely used process for forming suspensions and pastes into designed shapes, and is central to the manufacture of many products. In this article, the extrusion through a square-entry die of non-Brownian spheres suspended in Newtonian fluid is investigated using discrete element simulations, capturing individual particle-particle contacts and hydrodynamic interactions. The simulations reveal inhomogeneous velocity and stress distributions, originating in the inherent microstructure formed by the constituent particles. Such features are shown to be relevant to generic paste extrusion behaviour, such as extrudate swell. The pressure drop across the extruder is correlated with the extrudate flow rate, with the empirical fitting parameters being linked directly to particle properties such as surface friction, and processing conditions such as extruder wall roughness. Our model and results bring recent advances in suspension rheology into an industrial setting, laying foundations for future model development, predictive paste formulation and extrusion design. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T03:59:19.423286-05:
      DOI: 10.1002/aic.15768
       
  • Scaling Inter-tablet Coating Variability in a Horizontal Rotating Drum
    • Authors: J. Ban; R. Kumar, S. Agarwal, C. Wassgren
      Abstract: This study investigates how the drum-to-particle diameter ratio (D/d) affects the surface speed and inter-particle coating variability in geometrically similar coaters. Discrete element method simulations were used to model particle movement in different-sized, cylindrical drums with identical particle diameters, Froude numbers, fill volume fractions, and spray characteristics. The dimensionless streamwise surface speed profiles become increasingly symmetric as D/d increases, with the maximum speed increasing with D/d. The relationship between the maximum dimensionless speed and D/d is fit well with a power law expression. Inter-particle coating variability decreases with the square root of the number of drum revolutions after a sufficiently large number of drum revolutions. Increasing D/d increases, in a logarithmic manner, the number of drum revolutions required to reach a given degree of coating variability. A similar logarithmic coating variability trend was observed in simulations using almond-shaped pharmaceutical tablets, suggesting that the trend is independent of tablet shape. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-19T05:55:12.493545-05:
      DOI: 10.1002/aic.15758
       
  • Big data for microstructure-property relationships: A case study of
           predicting effective conductivities
    • Authors: Ole Stenzel; Matthias Neumann, Omar Pecho, Lorenz Holzer, Volker Schmidt
      Abstract: The analysis of big data is changing industries, businesses and research since large amounts of data are available nowadays. In the area of microstructures, acquisition of (3D tomographic image) data is difficult and time-consuming. It is shown that large amounts of data representing the geometry of virtual, but realistic 3D microstructures can be generated using stochastic microstructure modeling. Combining the model output with physical simulations and data mining techniques, microstructure-property relationships can be quantitatively characterized. Exemplarily, we aim to predict effective conductivities given the microstructure characteristics volume fraction, mean geodesic tortuosity and constrictivity. Therefore, we analyze 8119 microstructures generated by two different stochastic 3D microstructure models. This is - to the best of our knowledge - by far the largest set of microstructures that has ever been analyzed. Fitting artificial neural networks, random forests and classical equations, the prediction of effective conductivities based on geometric microstructure characteristics is possible. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-19T05:53:38.464866-05:
      DOI: 10.1002/aic.15757
       
  • Preemptive Dynamic Operation of Cryogenic Air Separation Units
    • Authors: Yanan Cao; Christopher L.E. Swartz, Jesus Flores-Cerrillo
      Abstract: As markets become more competitive and dynamic, manufacturing plants are undergoing transitions towards flexible, agile and low costs operations. Appropriate coordination within the supply chain is an important factor in manufacturing systems' performance. In this study, the impact of preemptive control action in advance of an upcoming demand change on the economic performance of a cryogenic air separation unit is investigated. The effects of various factors are explored through optimization formulations utilizing a high fidelity collocation based dynamic process model. This includes the amount of lead time, choice of manipulated inputs, direction of demand change, and liquid product market conditions. Plant performance is evaluated and analyzed through a comprehensive multi-part case study. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-10T11:35:36.36761-05:0
      DOI: 10.1002/aic.15753
       
  • Multi-parametric linear programming under global uncertainty
    • Authors: Vassilis M. Charitopoulos; Lazaros G. Papageorgiou, Vivek Dua
      Abstract: Multi-parametric programming has proven to be an invaluable tool for optimisation under uncertainty. Despite the theoretical developments in this area, the ability to handle uncertain parameters on the left-hand side remains limited and as a result, hybrid or approximate solution strategies have been proposed in the literature.In this work, a new algorithm is introduced for the exact solution of multi-parametric linear programming problems with simultaneous variations in the objective function's coefficients, the right-hand side and the left-hand side of the constraints. The proposed methodology is based on the analytical solution of the system of equations derived from the first order Karush-Kuhn-Tucker conditions for general linear programming problems using symbolic manipulation.Emphasis is given on the ability of the proposed methodology to handle efficiently the LHS uncertainty by computing exactly the corresponding non-convex critical regions while numerical studies underline further advantages of the proposed methodology, when compared to existing algorithms. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-10T11:35:35.228519-05:
      DOI: 10.1002/aic.15755
       
  • Dynamic Real-time Optimization with Closed-loop Prediction
    • Authors: Mohammad Zamry Jamaludin; Christopher L.E. Swartz
      Abstract: Process plants are operating in an increasingly global and dynamic environment, motivating the development of dynamic real-time optimization (DRTO) systems in order to account for transient behavior in the determination of economically optimal operating policies. This paper considers optimization of closed-loop response dynamics at the DRTO level in a two-layer architecture, with constrained MPC applied at the regulatory control level. A simultaneous solution approach is applied to the multilevel DRTO optimization problem, in which the convex MPC optimization subproblems are replaced by their necessary and sufficient Karush-Kuhn-Tucker (KKT) optimality conditions, resulting in a single-level mathematical program with complementarity constraints (MPCC). The performance of the closed-loop DRTO strategy is compared to that of the open-loop prediction counterpart through a multi-part case study that considers linear dynamic systems with different characteristics. The performance of the proposed strategy is further demonstrated through application to a nonlinear polymerization reactor grade transition problem. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-10T11:35:28.338417-05:
      DOI: 10.1002/aic.15752
       
  • Perspective: Teaching Professional Skills
    • Authors: Phil Wankat
      Abstract: After being invited to write a perspective on chemical engineering education for the AIChE Journal, I immediately wondered what I could contribute that had not already been covered in depth. After reading the previous Journal perspectives on chemical engineering education by Falconer1, Cussler2, and Varma and Grossmann3, I realized that development of professional skills (aka soft skills) had not been analyzed in detail. Professional skills such as communication, teamwork, and ethical behavior are often more important in an engineering career than technical ability. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-07T09:30:43.118685-05:
      DOI: 10.1002/aic.15747
       
  • Fe-Beta@CeO2 Core–Shell Catalyst with Tunable Shell Thickness for
           Selective Catalytic Reduction of NOx with NH3
    • Authors: Jixing Liu; Jian Liu, Zhen Zhao, Yuechang Wei, Weiyu Song
      Abstract: A series of core−shell structural deNOx catalysts using small-grain Beta supporting FeOx nanoparticles (NPs) as the core and tunable CeO2 thin film thickness as sheaths were designed and controllably synthesized. Their catalytic performances were tested for selective catalytic reduction of NOx with NH3 (NH3-SCR). It was found that CeO2 shell thickness plays an important role in influencing the acidity and redox properties of the catalysts. Fe-Beta@CeO2 core−shell catalysts exhibit excellent resistance to H2O and SO2 and high NOx conversion (above 90%) in the wide temperature range (225∼565°C). The kinetics result indicates that the coating of CeO2 shell significantly increases the pore diffusion resistance of Fe-Beta@CeO2 catalysts. Furthermore, in-situ DRIFT results reveal that CeO2 shell can promote the formation of NO2 and cis-N2O2− species. But too thick CeO2 shell (∼20 nm) would result in the formation of inactive nitrate species, and thereby lead to a decrease of high-temperature activity of the catalysts. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-06T05:40:26.1216-05:00
      DOI: 10.1002/aic.15743
       
  • Expeditious modeling of vapor transport and reactions in polymeric
           materials*
    • Authors: Yunwei Sun; Charles Tong, Stephen J. Harley, Elizabeth A. Glascoe
      Abstract: We present a methodology for approximating dynamic adsorption of vapor coupled with diffusion in polymeric materials. In previous publications, the dynamic adsorption was represented by ordinary differential equations (ODEs) and solved in concentration and parameter space. To accelerate the calculation, we have developed a statistical approximation method using computationally cheap surrogate models (e.g., algebraic polynomials) that replace the ODE solutions of adsorption and are coupled with the diffusion equations. Since the polynomial presentation of the adsorption term is obtained in a standard format prior to modeling coupled sorption-diffusion, the adsorption operator can be expressed as input data in the transport code. Compared to conventional operator-splitting methods, the polynomial approximation (PA) of adsorption offers better computational efficiency. The methodology is demonstrated and validated using a dynamic Langmuir adsorption model that is coupled to diffusion and absorption models and applied to a water vapor sorption-diffusion process in polydimethlysiloxane (PDMS) polymers. [copyright] 2017 American Institute of Chemical Engineers AIChE J., 2017 This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T05:45:58.503589-05:
      DOI: 10.1002/aic.15746
       
  • One-Pot Synthesis of Silver-Modified Sulfur-Tolerant Anode for SOFCs with
           an Expanded Operation Temperature Window
    • Authors: Jifa Qu; Wei Wang, Tao Yang, Yubo Chen, Zongping Shao
      Abstract: To develop solid oxide fuel cells (SOFCs) capable of operating on sulfur-containing practical fuels at intermediate temperatures, further improvement of the sulfur tolerance of a Ni+BaZr0.4Ce0.4Y0.2O3-δ (BZCY) anode is attempted through the addition of some metal modifiers (Fe, Co and Ag) by a one-pot synthesis approach. The effects of these modifiers on the electrical conductivity, morphology, sulfur tolerance and electrochemical activity of the anode are systematically studied. As a result, the cell with Ag-modified Ni+BZCY anode demonstrates highest power output when operated on 1000 ppm H2S-H2 fuel. Furthermore, the Ag-modified anode displays much better stability than Ni+BZCY with 1000 ppm H2S-H2 fuel at 600°C. These results suggest that the addition of Ag modifier into Ni+BZCY is a promising and efficient method for improving the sulfur tolerance of SOFCs. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-17T04:36:22.37746-05:0
      DOI: 10.1002/aic.15649
       
  • Issue information - table of contents
    • Pages: 2509 - 2510
      PubDate: 2017-06-06T14:25:50.313901-05:
      DOI: 10.1002/aic.15474
       
  • A continuum-approach modeling of surface composition and ternary component
           distribution inside low fat milk emulsions during single droplet drying
    • Authors: Aditya Putranto; Martin Foerster, Meng Wai Woo, Cordelia Selomulya, Xiao Dong Chen
      Pages: 2535 - 2545
      Abstract: Surface composition of dairy powders plays an important role in determining the functionality. However, the surface composition may be different from the bulk composition because of component migration during drying. In this study, a comprehensive mathematical model has been developed to describe the phenomena. To the best of our knowledge, it is the first mathematical model which predicts the dynamics of surface composition during drying. The model consists of a set of equations of conservation of mass of water, lactose, protein, and fat as well as conservation of heat and momentum in which the effects of diffusion induced material migration and surface activity are incorporated. This model is applicable to describe the kinetics of surface composition of dairy droplets during drying. It suggests that both diffusion and protein surface activity govern the component segregation during drying. The study indicates that the model implementing the measured initial surface composition as the initial conditions generates more realistic profiles than the one using the bulk composition. The modeling confirms that the difference between the surface and bulk composition that occurs prior to drying is not primarily governed by diffusion, but the emulsion's atomization behavior seems to play an essential role in the overrepresentation of fat. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2535–2545, 2017
      PubDate: 2017-02-06T10:20:31.172833-05:
      DOI: 10.1002/aic.15657
       
  • Kinetic modeling and process analysis for Desmodesmus sp. lutein
           photo-production
    • Authors: Ehecatl Antonio del Rio-Chanona; Nur rashid Ahmed, Dongda Zhang, Yinghua Lu, Keju Jing
      Pages: 2546 - 2554
      Abstract: Lutein is a high-value bioproduct synthesized by microalga Desmodesmus sp. In the current study two aspects of this process are thoroughly investigated: identifying the complex effects of light intensity and nitrate concentration on biomass growth and lutein synthesis, and constructing an accurate kinetic model capable of simulating the entire bioprocess dynamic performance, neither of which has been previously addressed. Three original contributions are presented here. First, it is found that completely opposite to a nitrogen-limiting culture, under nitrogen-sufficient conditions a higher lutein content is caused by a higher light intensity and lower nitrate concentration. Second, contrary to lutein content, total lutein production always increases with the increasing nitrate concentration. Third, through experimental verification, the proposed kinetic model is characterized by high accuracy and predictability, indicating its competence for future process design, control, and optimization. Based on the model, optimal light intensities for lutein production and microalgae growth are identified. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2546–2554, 2017
      PubDate: 2017-02-15T09:20:29.28594-05:0
      DOI: 10.1002/aic.15667
       
  • Effective particle diameters for simulating fluidization of non-spherical
           particles: CFD-DEM models vs. MRI measurements
    • Authors: C. M. Boyce; A. Ozel, N. P. Rice, G. J. Rubinstein, D. J. Holland, S. Sundaresan
      Pages: 2555 - 2568
      Abstract: Computational fluid dynamics—discrete element method (CFD-DEM) simulations were conducted and compared with magnetic resonance imaging (MRI) measurements (Boyce, Rice, and Ozel et al., Phys Rev Fluids. 2016;1(7):074201) of gas and particle motion in a three-dimensional cylindrical bubbling fluidized bed. Experimental particles had a kidney-bean-like shape, while particles were simulated as being spherical; to account for non-sphericity, “effective” diameters were introduced to calculate drag and void fraction, such that the void fraction at minimum fluidization (εmf) and the minimum fluidization velocity (Umf) in the simulations matched experimental values. With the use of effective diameters, similar bubbling patterns were seen in experiments and simulations, and the simulation predictions matched measurements of average gas and particle velocity in bubbling and emulsion regions low in the bed. Simulations which did not employ effective diameters were found to produce vastly different bubbling patterns when different drag laws were used. Both MRI results and CFD-DEM simulations agreed with classic analytical theory for gas flow and bubble motion in bubbling fluidized beds. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2555–2568, 2017
      PubDate: 2017-01-25T15:55:35.76575-05:0
      DOI: 10.1002/aic.15623
       
  • Full-physics simulations of spray-particle interaction in a bubbling
           fluidized bed
    • Authors: Maryam Askarishahi; Mohammad-Sadegh Salehi, Stefan Radl
      Pages: 2569 - 2587
      Abstract: Numerical simulations of a gas-particle-droplet system were performed using an Euler-Lagrange approach. Models accounting for (1) the interaction between droplets and particles, (2) evaporation from the droplet spray, as well as (3) evaporation of liquid from the surface of non-porous particles were considered. The implemented models were verified for a packed bed, as well as other standard flow configurations. The developed models were then applied for the simulation of flow, as well as heat and mass transfer in a fluidized bed with droplet injection. The relative importance of droplet evaporation vs. evaporation from the particle surface was quantified. It was proved that spray evaporation competes with droplet deposition and evaporation from the particle surface. Moreover, we show that adopting a suitable surface coverage model is vital when attempting to make accurate predictions of the particle's liquid content. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2569–2587, 2017
      PubDate: 2017-01-31T11:40:12.59772-05:0
      DOI: 10.1002/aic.15616
       
  • Modifying the inter-phase drag via solid volume fraction gradient for CFD
           simulation of fast fluidized beds
    • Authors: Mingze Su; Haibo Zhao
      Pages: 2588 - 2598
      Abstract: The conventional drag model in two-fluid simulation, which assumes uniform particle distribution in a computational grid, overestimates the drag force, thus failed in capturing the subgrid-scale strands and resolvable-scale clusters. This work proposed a new modification to the conventional drag model through considering the heterogeneous distribution of solid volume fraction (SVF), especially, in the inter-phase boundary (i.e., cluster boundary). The resulting drag model is a function of particle Reynolds number, SVF and the gradient of SVF. This straightforward modification is consistent with the elaborately filtered-approach-based modification method in nature. A CFD simulation for a two-dimensional riser was conducted to validate the new drag model. The outlet solid mass flux, axial and radial time-averaged voidages from the new drag model agreed well with the experimental measurements, and these results were far better than those from the conventional homogeneous drag models. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2588–2598, 2017
      PubDate: 2017-02-01T16:15:56.639296-05:
      DOI: 10.1002/aic.15573
       
  • Numerical modeling of adhesive particle mixing
    • Authors: Mohammad R. Tamadondar; Anders Rasmuson, Kyrre Thalberg, Ingela Niklasson Björn
      Pages: 2599 - 2609
      Abstract: The discrete element method is used to investigate adhesive particle mixing in a system that includes large carrier particles and fine particle agglomerates in a Couette mixer. The simulation starts with 200 carriers and 10 agglomerates with 1000 fine particles each. During mixing, the agglomerates are broken, fractions adhere to the carriers, and there is continuous redistribution of fines between carriers. The focus is to obtain information on the quantity and quality of fine particles adhered to carriers by postprocessing the simulation data. Variation in the structure of agglomerates due to shearing is studied over mixing time. Findings indicate that major fraction of fine particles are dispersed evenly onto the surface of carriers and the rest are in form of free debris. A time-dependent index is introduced to predict the degree of mixing. Finally, the adhesion force between carriers and coated layers is observed to have a peak at 1 nN. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2599–2609, 2017
      PubDate: 2017-02-02T13:25:28.079371-05:
      DOI: 10.1002/aic.15654
       
  • Sand consolidation via latex destabilization
    • Authors: Wei Jin Gun; Alexander F. Routh, Dana Aytkhozhina, Mark Aston
      Pages: 2610 - 2617
      Abstract: This article investigates the use of a commercial latex dispersion for the purpose of sand consolidation in oil wells. The aim is to consolidate sand without compromising permeability and to prevent sanding during water breakthrough. This is achieved by injecting latex dispersions into a sand-pack and relying on potassium chloride flushes, or irreducible saline water in the reservoir, to destabilize the latex onto the sand surface. This forms a latex network connecting and holding the sand grains together. The strength of the consolidation in the laboratory is determined by flowing water and oil at various flow rates and investigating the amount of sand produced. The effect of different parameters, such as the amount of latex injected, the latex salinity, and salinity of the irreducible water are discussed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2610–2617, 2017
      PubDate: 2017-02-15T09:15:31.948448-05:
      DOI: 10.1002/aic.15668
       
  • In situ characterization of mixing and sedimentation dynamics in an
           impinging jet ballast tank via acoustic backscatter
    • Authors: Jaiyana Bux; Neepa Paul, Timothy N. Hunter, Jeffrey Peakall, Jonathan M. Dodds, Simon Biggs
      Pages: 2618 - 2629
      Abstract: Impinging jets are utilized in numerous applications, including nuclear waste treatment, for both the erosion of sediment beds and maintaining particulates in suspension. Pulse-echo ultrasonic methods offer great potential for the in situ monitoring of critical mixing and settling dynamics, in concentrated dispersions. A non-active scaled version of a Highly Active Storage Tank at Sellafield, UK, was profiled with an acoustic backscatter system under various jet firing conditions. An advanced analysis technique enabled the direct quantification of dispersion concentration changes from the converted backscatter attenuation. Hence, the erosion and mixing capability of the jets, and settling kinetics were characterized. It was found that jet operation alone provided inadequate localized mixing of eroded sediment. An additional air-lift process operation was required to hinder the rapid re-settling of dispersed particulates. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2618–2629, 2017
      PubDate: 2017-03-02T00:50:59.491611-05:
      DOI: 10.1002/aic.15683
       
  • Euler–euler anisotropic gaussian mesoscale simulation of homogeneous
           cluster-induced gas–particle turbulence
    • Authors: Bo Kong; Rodney O. Fox, Heng Feng, Jesse Capecelatro, Ravi Patel, Olivier Desjardins, Rodney O. Fox
      Pages: 2630 - 2643
      Abstract: An Euler–Euler anisotropic Gaussian approach (EE-AG) for simulating gas–particle flows, in which particle velocities are assumed to follow a multivariate anisotropic Gaussian distribution, is used to perform mesoscale simulations of homogeneous cluster-induced turbulence (CIT). A three-dimensional Gauss–Hermite quadrature formulation is used to calculate the kinetic flux for 10 velocity moments in a finite-volume framework. The particle-phase volume-fraction and momentum equations are coupled with the Eulerian solver for the gas phase. This approach is implemented in an open-source CFD package, OpenFOAM, and detailed simulation results are compared with previous Euler–Lagrange simulations in a domain size study of CIT. The results demonstrate that the proposed EE-AG methodology is able to produce comparable results to EL simulations, and this moment-based methodology can be used to perform accurate mesoscale simulations of dilute gas–particle flows. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2630–2643, 2017
      PubDate: 2017-03-03T09:10:45.919574-05:
      DOI: 10.1002/aic.15686
       
  • Linear model predictive control for transport-reaction processes
    • Authors: Qingqing Xu; Stevan Dubljevic
      Pages: 2644 - 2659
      Abstract: The article deals with systematic development of linear model predictive control algorithms for linear transport-reaction models emerging from chemical engineering practice. The finite-horizon constrained optimal control problems are addressed for the systems varying from the convection dominated models described by hyperbolic partial differential equations (PDEs) to the diffusion models described by parabolic PDEs. The novelty of the design procedure lies in the fact that spatial discretization and/or any other type of spatial approximation of the process model plant is not considered and the system is completely captured with the proposed Cayley-Tustin transformation, which maps a plant model from a continuous to a discrete state space setting. The issues of optimality and constrained stabilization are addressed within the controller design setting leading to the finite constrained quadratic regulator problem, which is easily realized and is no more computationally intensive than the existing algorithms. The methodology is demonstrated for examples of hyperbolic/parabolic PDEs. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2644–2659, 2017
      PubDate: 2017-01-25T11:40:33.889906-05:
      DOI: 10.1002/aic.15592
       
  • Robust batch-to-batch optimization in the presence of model-plant mismatch
           and input uncertainty
    • Authors: Rubin Hille; Jasdeep Mandur, Hector M. Budman
      Pages: 2660 - 2670
      Abstract: In model-based optimization in the presence of model-plant mismatch, the set of model parameter estimates which satisfy an identification objective may not result in an accurate prediction of the gradients of the cost-function and constraints. To ensure convergence to the optimum, the predicted gradients can be forced to match the measured gradients by adapting the model parameters. Since updating all available parameters is impractical due to estimability problems and overfitting, there is a motivation for adapting a subset of parameters for updating the predicted outputs and gradients. This article presents an approach to select a subset of parameters based on the sensitivities of the model outputs and of the cost function and constraint gradients. Furthermore, robustness to uncertainties in initial batch conditions is introduced using a robust formulation based on polynomial chaos expansions. The improvements in convergence to the process optimum and robustness are illustrated using a fed-batch bioprocess. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2660–2670, 2017
      PubDate: 2017-01-27T11:30:40.331637-05:
      DOI: 10.1002/aic.15645
       
  • Game theory approach to optimal design of shale gas supply chains with
           consideration of economics and life cycle greenhouse gas emissions
    • Authors: Jiyao Gao; Fengqi You
      Pages: 2671 - 2693
      Abstract: This article addresses the optimal design of a non-cooperative shale gas supply chain based on a game theory approach. Instead of assuming a single stakeholder as in centralized models, we consider different stakeholders, including the upstream shale gas producer and the midstream shale gas processor. Following the Stackelberg game, the shale gas producer is identified as the leader, whose objectives include maximizing its net present value (NPV) and minimizing the life cycle greenhouse gas (GHG) emissions. The shale gas processor is identified as the follower that takes actions after the leader to maximize its own NPV. The resulting problem is a multiobjective mixed-integer bilevel linear programming problem, which cannot be solved directly using any off-the-shelf optimization solvers. Therefore, an efficient projection-based reformulation and decomposition algorithm is further presented. Based on a case study of the Marcellus shale play, the non-cooperative model not only captures the interactions between stakeholders but also provides more realistic solutions. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2671–2693, 2017
      PubDate: 2017-02-01T16:20:47.628147-05:
      DOI: 10.1002/aic.15605
       
  • The analysis of solubility, absorption kinetics of CO2 absorption into
           aqueous 1-diethylamino-2-propanol solution
    • Authors: Helei Liu; Min Xiao, Zhiwu Liang, Paitoon Tontiwachwuthikul
      Pages: 2694 - 2704
      Abstract: In this present work, the CO2 absorption performance of aqueous 1-diethylamino-2-propanol (1DEA2P) solution was studied with respect to CO2 equilibrium solubility, absorption kinetics, and absorption heat. The equilibrium solubility of CO2 in 2M 1DEA2P solution was measured over the temperature range from 298 to 333 K and CO2 partial pressure range from 8 to101 kPa. The absorption kinetics data were developed and analyzed using the base-catalyzed hydration mechanism and artificial neural network models (radial basis function neural network [RBFNN] and back-propagation neural network [BPNN] models) with an acceptable absolute average deviation of 10% for base-catalyzed hydration mechanism, 2.6% for RBFNN model and 1.77% for BPNN model, respectively. The CO2 absorption heat of 1DEA2P was estimated to be −43.6 kJ/mol. In addition, the ions (1DEA2P, 1DEA2PH+,HCO3−, CO32−) speciation plots of the 1DEA2P-CO2-H2O system were developed to further understand the reaction process of 1DEA2P with CO2. Based on a comparison with conventional amines (e.g., MEA, DEA, MDEA) and alternative amines (i.e., 1DMA2P and 4-(diethylamino)−2-butanol [DEAB]), 1DEA2P exhibited good performance with respect to CO2 equilibrium solubility, reaction kinetics, and CO2 absorption heat. Meanwhile, the overall evaluation of 1DEA2P for application in CCS in terms of absorption and desorption is presented, giving helpful information for the screening of these novel amines. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2694–2704, 2017
      PubDate: 2017-02-01T16:10:35.575259-05:
      DOI: 10.1002/aic.15621
       
  • Handling multi-rate and missing data in variable duration economic model
           predictive control of batch processes
    • Authors: Mudassir M. Rashid; Prashant Mhaskar, Christopher L. E. Swartz
      Pages: 2705 - 2718
      Abstract: In the present work, we consider the problem of variable duration economic model predictive control of batch processes subject to multi-rate and missing data. To this end, we first generalize a recently developed subspace-based model identification approach for batch processes to handle multi-rate and missing data by utilizing the incremental singular value decomposition technique. Exploiting the fact that the proposed identification approach is capable of handling inconsistent batch lengths, the resulting dynamic model is integrated into a tiered EMPC formulation that optimizes process economics (including batch duration). Simulation case studies involving application to the energy intensive electric arc furnace process demonstrate the efficacy of the proposed approach compared to a traditional trajectory tracking approach subject to limited availability of process measurements, missing data, measurement noise, and constraints. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2705–2718, 2017
      PubDate: 2017-02-02T13:35:29.013383-05:
      DOI: 10.1002/aic.15619
       
  • A geometric framework for monitoring and fault detection for periodic
           processes
    • Authors: Ray Wang; Thomas F. Edgar, Michael Baldea
      Pages: 2719 - 2730
      Abstract: Although cyclical operation systems are relatively widespread in practice (notably in the realm of physical separations, for example, pressure-swing adsorption and chromatography), the development of specific fault detection mechanisms has received little attention compared to the extensive efforts dedicated to continuous or batch processes. Here, a novel geometric approach for process fault detection is proposed. Specifically, a time-explicit multivariable representation of data collected from the process, which provides a natural framework for defining “normal” operation and the corresponding confidence regions is developed. On this basis, a two-step fault detection approach is proposed, based on detecting intercycle variations to locate a faulty cycle, and intracycle changes to determine the exact timing of a fault. The theoretical developments are illustrated with two simulation case studies. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2719–2730, 2017
      PubDate: 2017-02-02T13:30:55.92151-05:0
      DOI: 10.1002/aic.15638
       
  • Characterizations of surfactant synthesized from Jatropha oil and its
           application in enhanced oil recovery
    • Authors: Sudhir Kumar; Amit Kumar, Ajay Mandal
      Pages: 2731 - 2741
      Abstract: Surfactants are frequently used in chemical enhanced oil recovery (EOR) as it reduces the interfacial tension (IFT) to an ultra-low value and also alter the wettability of oil-wet rock, which are important mechanisms for EOR. However, most of the commercial surfactants used in chemical EOR are very expensive. In view of that an attempt has been made to synthesis an anionic surfactant from non-edible Jatropha oil for its application in EOR. Synthesized surfactant was characterized by FTIR, NMR, dynamic light scattering, thermogravimeter analyser, FESEM, and EDX analysis. Thermal degradability study of the surfactant shows no significant loss till the conventional reservoir temperature. The ability of the surfactant for its use in chemical EOR has been tested by measuring its physicochemical properties, viz., reduction of surface tension, IFT and wettability alteration. The surfactant solution shows a surface tension value of 31.6 mN/m at its critical micelle concentration (CMC). An ultra-low IFT of 0.0917 mN/m is obtained at CMC of surfactant solution, which is further reduced to 0.00108 mN/m at optimum salinity. The synthesized surfactant alters the oil-wet quartz surface to water-wet which favors enhanced recovery of oil. Flooding experiments were conducted with surfactant slugs with different concentrations. Encouraging results with additional recovery more than 25% of original oil in place above the conventional water flooding have been observed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2731–2741, 2017
      PubDate: 2017-02-02T13:35:45.969035-05:
      DOI: 10.1002/aic.15651
       
  • Robustness of bioprocess feedback control to biodiversity
    • Authors: Francis Mairet; Olivier Bernard
      Pages: 2742 - 2750
      Abstract: The design of control laws for bioprocesses is generally based on simplified single-species models. Biodiversity is nonetheless inherent in any bioreactor where contamination leads to a mixture of different species or strains. This paper proposes to define and study the robustness to biodiversity of bioprocess control laws: given a control law designed for one species, what happens when additional species are present' is the approach is illustrated with a well-used control law which regulates substrate concentration using measurement of growth activity. Depending on the properties of the additional species, the control law can lead to the required objective, but also to an undesired monospecies equilibrium point, coexistence, or even a failure point. Finally, for this case, the robustness can be improved by a saturation of the control. Robustness to biodiversity is a difficult issue which should be better understood and accounted for in the control design. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2742–2750, 2017
      PubDate: 2017-02-03T15:05:35.422234-05:
      DOI: 10.1002/aic.15604
       
  • A game theoretic framework for petroleum refinery strategic production
           planning
    • Authors: Philip Tominac; Vladimir Mahalec
      Pages: 2751 - 2763
      Abstract: A game theoretic framework for strategic refinery production planning is presented in which strategic planning problems are formulated as non-cooperative potential games whose solutions represent Nash equilibria. The potential game model takes the form of a nonconvex nonlinear program (NLP) and we examine an additional scenario extending this to a nonconvex mixed integer nonlinear program (MINLP). Tactical planning decisions are linked to strategic decision processes through a potential game structure derived from a Cournot oligopoly-type game in which multiple crude oil refineries supply several markets. Two scenarios are presented which illustrate the utility of the game theoretic framework in the analysis of production planning problems in competitive scenarios. Solutions to these problems are interpreted as mutual best responses yielding maximum profit in the competitive planning game. The resulting production planning decisions are rational in a game theoretic sense and are robust to deviations in competitor strategies. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2751–2763, 2017
      PubDate: 2017-02-04T21:25:37.018348-05:
      DOI: 10.1002/aic.15644
       
  • A hybrid numerical-symbolic solving strategy for equation-oriented process
           simulation and optimization
    • Authors: Fei Zhao; Xi Chen, Lingyu Zhu
      Pages: 2764 - 2780
      Abstract: The equation-oriented (EO) and sequential modular (SM) methods are two typical approaches for numerical process simulation and optimization. For a large-scale system, the EO method usually suffers from difficulties in variable initialization. The SM method, conversely, can suffer from slow convergence and requires experience in choosing appropriate tear variables. In this article, a novel strategy combining numerical and symbolic approaches is proposed for solving process systems represented by polynomials. First, a digraph method is developed to identify the subset of equations that should be solved simultaneously. Then, a symbolic computation method based on Gröbner basis is proposed to reformulate the simultaneous equations as a completely sequential model with a triangular structure. Last, the reformulated model is solved sequentially without any iterative tearing process. The case studies show that the proposed strategy can significantly improve the solving efficiency and robustness for process simulation and optimization. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2764–2780, 2017
      PubDate: 2017-02-09T01:24:17.985383-05:
      DOI: 10.1002/aic.15622
       
  • Hierarchical monitoring of industrial processes for fault detection, fault
           grade evaluation, and fault diagnosis
    • Authors: Lijia Luo; Robert J. Lovelett, Babatunde A. Ogunnaike
      Pages: 2781 - 2795
      Abstract: Traditional process monitoring methods cannot evaluate and grade the degree of harm that faults can cause to an industrial process. Consequently, a process could be shut down inadvertently when harmless faults occur. To overcome such problems, we propose a hierarchical process monitoring method for fault detection, fault grade evaluation, and fault diagnosis. First, we propose fault grade classification principles for subdividing faults into three grades: harmless, mild, and severe, according to the harm the fault can cause to the process. Second, two-level indices are constructed for fault detection and evaluation, with the first-level indices used to detect the occurrence of faults while the second-level indices are used to determine the fault grade. Finally, to identify the root cause of the fault, we propose a new online fault diagnosis method based on the square deviation magnitude. The effectiveness and advantages of the proposed methods are illustrated with an industrial case study. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2781–2795, 2017
      PubDate: 2017-02-09T11:01:03.158302-05:
      DOI: 10.1002/aic.15662
       
  • An in silico evaluation of data-driven optimization of biopharmaceutical
           processes
    • Authors: Zhenyu Wang; Christos Georgakis
      Pages: 2796 - 2805
      Abstract: Two methodological improvements of the design of dynamic experiments (C. Georgakis, Ind Eng Chem Res. 2013) for the modeling and optimization of (semi-) batch processes are proposed. Their effectiveness is evaluated in two representative classes of biopharmaceutical processes. First, we incorporate prior process knowledge in the design of the experiments. Many batch processes and, in particular, biopharmaceutical processes are usually not understood completely to enable the development of an accurate knowledge-driven model. However, partial process knowledge is often available and should not be ignored. We demonstrate here how to incorporate such knowledge. Second, we introduce an evolutionary modeling and optimization approach to minimize the initial number of experiments in the face of budgetary and time constraints. The proposed approach starts with the estimation of only a linear Response Surface Model, which requires the minimum number of experiments. Accounting for the model's uncertainty, the proposed approach calculates a process optimum that meets a maximum uncertainty constraint. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2796–2805, 2017
      PubDate: 2017-02-10T08:35:51.475635-05:
      DOI: 10.1002/aic.15659
       
  • Estimation of spatial alumina concentration in an aluminum reduction cell
           using a multilevel state observer
    • Authors: Yuchen Yao; Cheuk-Yi Cheung, Jie Bao, Maria Skyllas-Kazacos, Barry J. Welch, Sergey Akhmetov
      Pages: 2806 - 2818
      Abstract: In the Hall-Héroult process, spatial variations in alumina concentration are very difficult to measure and impossible to estimate from the conventionally monitored line amperage and cell voltage. This article presents an approach to estimate in real time the alumina concentration distribution in an aluminum reduction cell based on individual anode current measurements. One of the key difficulties is that the localized mass transfer rates are unknown. To overcome this issue, a multilevel state observer is developed based on the robust extended Kalman filter. The approach utilizes a dynamic model of a reduction cell that is discretized subsequently level by level, where the estimated variables at each level are used to estimate more detailed alumina concentration spatial distribution at the next level. The proposed approach is validated in an experimental study using an industrial cell. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2806–2818, 2017
      PubDate: 2017-02-21T14:41:41.791104-05:
      DOI: 10.1002/aic.15656
       
  • Intensified and safe ozonolysis of fatty acid methyl esters in liquid CO2
           in a continuous reactor
    • Authors: Michael D. Lundin; Andrew M. Danby, Geoffrey R. Akien, Padmesh Venkitasubramanian, Kevin J. Martin, Daryle H. Busch, Bala Subramaniam
      Pages: 2819 - 2826
      Abstract: We demonstrate a continuous reactor for performing the ozonolysis of fatty acid methyl esters (FAMEs) using liquid CO2 as solvent. The fast reaction kinetics allows the use of small-volume reactors to completely convert the FAMEs, forming secondary ozonides as the primary products. The short residence times also help maximize the yields of the secondary ozonides by minimizing over-oxidation and the formation of oligomeric products. The liquid CO2 medium promotes safe reactor operation by providing an essential fraction of overall reactor cooling and by diluting the vapor phase organics. We also demonstrate a continuous stirred reactor for the safe thermal decomposition of the secondary ozonides to their corresponding acids and aldehydes. Using a lumped kinetic model for the thermal decomposition of the ozonolysis products, we estimate activation energy values of 108.6 ± 0.6 kJ mol−1 for the decomposition of secondary ozonides and 122 ± 3 kJ mol−1 for the decomposition of the undesired oligomeric species. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2819–2826, 2017
      PubDate: 2017-01-20T13:20:26.582445-05:
      DOI: 10.1002/aic.15630
       
  • High performance of la-promoted Fe2O3/α-Al2O3 oxygen carrier for
           chemical looping combustion
    • Authors: Ming Tian; Chaojie Wang, Lin Li, Xiaodong Wang
      Pages: 2827 - 2838
      Abstract: Iron oxide supported oxygen carrier (OC) is regarded to a promising candidate for chemical looping combustion (CLC). However, phase separation between Fe2O3 and supports often occurs resulted from the severe sintering of supports during calcination, which leads to the sintering and breakage of Fe2O3 thus the decrease of redox reactivity. In this article, La-promoted Fe2O3/α-Al2O3 were used as OCs for CLC of CH4 and for the first time found that the OC with the addition of 18 wt % La exhibited outstanding reactivity and redox stability during 50 cycles of CLC of CH4. Such a superior performance originated from the formation of LaAl12O19 hexaaluminate (La-HA) phase with not only small particle size but also excellent thermal stability at CLC conditions, which worked as a binder to prevent the phase separation thereby the sintering and breakage of active species α-Fe2O3 were avoided during reaction. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2827–2838, 2017
      PubDate: 2017-01-22T16:10:32.289149-05:
      DOI: 10.1002/aic.15634
       
  • Hydrogenation of methyl acetate to ethanol by Cu/ZnO catalyst encapsulated
           in SBA-15
    • Authors: Yue Wang; Junyu Liao, Jian Zhang, Shengping Wang, Yujun Zhao, Xinbin Ma
      Pages: 2839 - 2849
      Abstract: The hydrogenation of methyl acetate (MA) is one of the important key processes for synthesis of ethanol from syngas. This work reports a highly efficient Cu-ZnO/SBA-15 catalyst prepared by facile solid-state grinding method. Both copper and zinc species were encapsulated in SBA-15 in high dispersion with the presence of organic template. The mixed homogeneity and interaction between copper and zinc species was enhanced as well with the help of organic template, resulting in the formation of Cu+ species in the reduced catalysts. Moreover, TOFCu(0) linearly increased with the Cu+/Cu0 ratio, indicating that a high proportion of Cu+/Cu0 induced by ZnO should be a key prerequisite to achieve favorable hydrogenation performance. It seems that the Cu+ species originated from Cu-ZnOx species are more active than that from Cu-O-Si species in the activation of MA. These results may provide an inspiration in rational design of Cu-ZnO-based catalysts for esters hydrogenation. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2839–2849, 2017
      PubDate: 2017-01-25T15:55:28.838795-05:
      DOI: 10.1002/aic.15620
       
  • Monte Carlo real coded genetic algorithm (MC-RGA) for radioactive particle
           tracking (RPT) experimentation
    • Authors: Ashutosh Yadav; Manojkumar Ramteke, Harish Jagat Pant, Shantanu Roy
      Pages: 2850 - 2863
      Abstract: Radioactive particle tracking (RPT) technique is a non-invasive velocimetry technique, extensively applied to study hydrodynamics of dense multiphase systems. In this technique, the position of a radioactive tracer particle, designed to mimic the phase of interest, is followed as a Lagrangian marker of point velocity. Computational limitations encountered during tracer particle position reconstruction (which is an inherently slow process) have thus far restricted the use of this versatile technique only to small-scale process vessels. Here, we present a noteworthy improvement over the classical Monte Carlo algorithm for tracer particle position reconstruction, whereby we enhance the convergence and computational speed of the algorithm using Real Coded Genetic Algorithm optimization. This modification results in drastic reduction in computational time required for detector parameter estimation, and altogether eliminates the need for the “distance-count map,” which was earlier inherent to RPT experimentation. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2850–2863, 2017
      PubDate: 2017-01-26T13:00:37.607531-05:
      DOI: 10.1002/aic.15596
       
  • Quantification of metal-acid balance in hydroisomerization catalysts: A
           step further toward catalyst design
    • Authors: Pedro S. F. Mendes; João M. Silva, M. Filipa Ribeiro, Pascal Duchêne, Antoine Daudin, Christophe Bouchy
      Pages: 2864 - 2875
      Abstract: A methodology was developed to interpret the results of n-paraffins hydroisomerization over bifunctional catalysts based on two simple kinetic models used consecutively. First, a macrokinetic model was used to obtain the corresponding turnover frequency over the acid sites and the maximum of C16 isomer yield. Second, a dual-function model was used to correlate these catalytic descriptors to the ratio of metal to acid sites of the catalyst. To illustrate the methodology, Pt/HBEA and Pt/HUSY catalysts with different Pt loadings were evaluated. The impact of metal-acid balance on the catalytic turnover frequency and the maximal C16 isomer yield were adequately captured for the bifunctional HUSY and HBEA catalysts. Moreover, the parameters of the dual-function model revealed to be intrinsic to the catalytic properties of the zeolite under the scope. This methodology is believed to be of interest for information-driven catalyst design for the hydroisomerization of n-paraffins. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2864–2875, 2017
      PubDate: 2017-01-26T12:20:36.197965-05:
      DOI: 10.1002/aic.15613
       
  • Regulating the micromixing efficiency of a novel helical tube reactor by
           premixing behavior optimization
    • Authors: Jiang-Zhou Luo; Guang-Wen Chu, Yong Luo, Moses Arowo, Bao-Chang Sun, Jian-Feng Chen
      Pages: 2876 - 2887
      Abstract: In this work, a novel helical tube reactor (HTR) was constructed, including a pre-mixer for adjusting the premixing behavior of reactants and a helical tube as a further mixing unit. The pre-mixer was modified to optimize the premixing behavior by using two methods, named as tangential-feeding and insertion of a helical baffle. The premixing behaviors were investigated via computational fluid dynamics (CFD) simulation. Simulation results indicated that both methods can change the fluid flow, enhance the turbulence kinetic energy, and improve the premixing performance in the pre-mixers. Based on the results of CFD simulation, it could be predicted that the micromixing efficiency of the HTR can be regulated by these methods accordingly. Then the predicated results were confirmed experimentally by a parallel competing reaction. Furthermore, the relationship between the premixing performance increasing and the corresponding micromixing efficiency increasing of the HTR was quantitatively analyzed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2876–2887, 2017
      PubDate: 2017-01-30T10:20:55.756113-05:
      DOI: 10.1002/aic.15641
       
  • Effects of tunable acidity and basicity of Nb-KIT-6 catalysts on ethanol
           conversion: Experiments and kinetic modeling
    • Authors: Hongda Zhu; Raghunath V. Chaudhari, Bala Subramaniam, Anand Ramanathan, Jian-Feng Wu
      Pages: 2888 - 2899
      Abstract: The relative amounts of acidic and basic sites in niobium-containing ordered mesoporous silicates (Nb-KIT-6) are tunable with metal loading. The acidity and basicity change from 0.11 to 0.34 mmol NH3-equiv./g cat. and 0.17 to 0.31 mmol CO2-equiv./g cat., respectively, as the Nb loading is increased from 1.5 to 10.9%. This work harnesses this unique feature to better understand acidity and basicity effects on ethanol conversion activity and product selectivity. It is shown that the yields of ethylene and acetaldehyde, the dominant products, are tuned with Nb loading. Catalyst characterization results and designed kinetic experiments provide evidence of acid-base pairs involved in the formation of various products. A macrosite kinetic model based on these observations and published mechanistic pathways fits the data for formation of the major products (ethylene, acetaldehyde, diethyl ether, and ethane) remarkably well. These results provide guidance for the rational design of bifunctional mesoporous materials exhibiting tunable acidity and basicity. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2888–2899, 2017
      PubDate: 2017-02-02T13:20:30.733713-05:
      DOI: 10.1002/aic.15648
       
  • Modulating morphology and textural properties of ZrO2 for supported Ni
           catalysts toward dry reforming of methane
    • Authors: Weizuo Li; Zhongkui Zhao, Guiru Wang
      Pages: 2900 - 2915
      Abstract: This work presents a facile and efficient approach to modulate morphology and textural properties of ZrO2 through ammonium fluoride-urea assisted hydrothermal (FUAH) method with diverse parameters including molar ratio of NH4F to zirconium (nf/z), molar ratio of urea to zirconium (nu/z), hydrothermal temperature (Thydroth), and hydrothermal time (thydroth), which serve as support for supported Ni catalysts toward dry reforming of methane (DRM) to produce synthesis gas. The plausible mechanism for forming ZrO2 supports with different morphologies under diverse hydrothermal conditions was proposed. Various characterization techniques were employed to investigate the effect of preparation parameters on the morphology and textural properties of the as-synthesized ZrO2 supports, as well as to reveal the structure-performance relationship of the Ni/ZrO2 catalysts prepared by L-arginine assisted incipient wetness impregnation method toward DRM reaction. The developed supported Ni catalyst on hierarchically structured ZrO2 with pinecone shape prepared by FUAH method (Ni/ZrO2-FUAH) demonstrates higher activity and stability for DRM than that on ZrO2 prepared by traditional hydrothermal method (Ni/ZrO2-H). The higher activity of Ni/ZrO2-FUAH than Ni/ZrO2-H can be ascribed to the higher Ni dispersion, smaller Ni crystalline size, and enhanced reducibility of NiO, significantly affected by morphology of support, as well as the higher coke-resistance catalytic stability can be ascribed to smaller Ni particle size and stronger Ni-support interaction, strongly dependent on morphology and textural properties of ZrO2 supports that affected by FUAH process parameters. The outstanding catalytic performance of the developed Ni/ZrO2-FUAH catalyst allows it to be a promising candidate for synthesis gas production through DRM reaction. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2900–2915, 2017
      PubDate: 2017-02-09T11:05:43.443821-05:
      DOI: 10.1002/aic.15661
       
  • Synergetic coupling of photo and thermal energy for efficient hydrogen
           production by formic acid reforming
    • Authors: Rui Song; Bing Luo, Maochang Liu, Jiafeng Geng, Dengwei Jing, Huan Liu
      Pages: 2916 - 2925
      Abstract: Most photocatalytic reactions are conducted near room temperature. In this work, we explored photothermal hydrogen production in a carefully designed photo reactor with external heating. Light sources of different wavelength bands were investigated. Formic acid was used as sacrificial regent to study the photothermal hydrogen production activity. Interestingly, the photothermal reaction is not the simple sum of the photo and thermal effects but their synergetic coupling and at 90°C it is 8.1 and 4.2 times of that under photo or thermal conditions alone. With thermal excitation, the bound electrons in Pt can be excited which can easily overcome the energy barrier between Pt and lowest unoccupied molecular orbital of the adsorbed reactants. Activation of the substrate itself by light is also found to be crucial to trigger such photothermal reaction. It is therefore different from traditional plasma resonance induced photothermal reaction where long wavelength IR light is more preferred. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2916–2925, 2017
      PubDate: 2017-02-09T11:00:38.519548-05:
      DOI: 10.1002/aic.15663
       
  • Diffusion-limited dissolution of spherical particles: A critical
           evaluation and applications of approximate solutions
    • Authors: Xiaoling Guo; Jilt Sietsma, Yongxiang Yang, Zhi Sun, Muxing Guo
      Pages: 2926 - 2934
      Abstract: The analytical and numerical description of the effective dissolution kinetics of spherical particles into a solvent is often difficult in chemical and metallurgical engineering. The crucial first step is to identify the dissolution mechanisms, and subsequently, relevant kinetics parameters can be calculated. In this article, three frequently used approximations, i.e., the invariant-field (IF) (Laplace), reverse-growth (RG), and invariant-size (IS) (stationary-interface) approximations, are systematically discussed and compared with numerical simulation results. The relative errors of the dissolution curves and total dissolution time of the three approximations to the numerical simulations are calculated. The results reveal the appropriate application ranges of the approximations for given precision levels. With further experimental validation, this research provides a methodology to properly assess dissolution kinetics and adequately estimate effective diffusion coefficients and activation energy under the experimental uncertainties. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2926–2934, 2017
      PubDate: 2017-02-22T09:35:49.549336-05:
      DOI: 10.1002/aic.15676
       
  • Highly active and selective Co-based Fischer–Tropsch catalysts derived
           from metal–organic frameworks
    • Authors: Yanpeng Pei; Zhong Li, Yingwei Li
      Pages: 2935 - 2944
      Abstract: The design of supported Co-based Fischer–Tropsch (F–T) catalysts with suitable reducibility, dispersion, loading, and nanoparticle structure is necessary so that high catalytic activity and selectivity for C5+ hydrocarbons can be achieved. Herein, we report that pyrolyzing a Co-metal–organic framework-71 precursor can provide porous carbon-supported Co catalysts with completely reduced, well-dispersed face-centered cubic (FCC) Co nanoparticles (∼10 nm in average size). The catalysts can be further tailored dimensionally by doping with Si species, and the FCC Co nanoparticles can be partially transformed into hexagonal close-packed Co via a Co2C intermediate. All the as-prepared catalysts had extremely high Co site density (>3.5 × 10−4 mol/g-cat.) because they had a high number of Co active sites and low mass. Aside from having high F–T activity and C5+ selectivity, with diesel fuels being the main constituents, they showed unprecedentedly high C5+ space time yields (up to 1.45 g/(g-cat. h)) as compared to conventional Co catalysts. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2935–2944, 2017
      PubDate: 2017-02-25T07:25:28.726803-05:
      DOI: 10.1002/aic.15677
       
  • The kinetics of polyurethane structural foam formation: Foaming and
           polymerization
    • Authors: Rekha R. Rao; Lisa A. Mondy, Kevin N. Long, Mathew C. Celina, Nicholas Wyatt, Christine C. Roberts, Melissa M. Soehnel, Victor E. Brunini
      Pages: 2945 - 2957
      Abstract: Kinetic models have been developed to understand the manufacturing of polymeric foams, which evolve from low viscosity Newtonian liquids, to bubbly liquids, finally producing solid foam. Closed-form kinetics are formulated and parameterized for PMDI-10, a fast curing polyurethane, including polymerization and foaming. PMDI-10 is chemically blown, where water and isocyanate react to form carbon dioxide. The isocyanate reacts with polyol in a competing reaction, producing polymer. Our approach is unique, although it builds on our previous work and the polymerization literature. This kinetic model follows a simplified mathematical formalism that decouples foaming and curing, including an evolving glass transition temperature to represent vitrification. This approach is based on IR, DSC, and volume evolution data, where we observed that the isocyanate is always in excess and does not affect the kinetics. The kinetics are suitable for implementation into a computational fluid dynamics framework, which will be explored in subsequent articles. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2945–2957, 2017
      PubDate: 2017-03-01T05:30:29.476213-05:
      DOI: 10.1002/aic.15680
       
  • Aqueous-phase ketonization of acetic acid over Zr/Mn mixed oxides
    • Authors: Kejing Wu; Mingde Yang, Yu Chen, Weihua Pu, Husheng Hu, Yulong Wu
      Pages: 2958 - 2967
      Abstract: Aqueous-phase ketonization possesses significant advantages over gas- or organic-phase ketonization for improved conversion efficiency of aqueous fraction accompanied by algal bio-oil production. In this study, synthetized ZrO2 and Zr/Mn oxides are used for aqueous-phase ketonization of acetic acid. ZrMn0.5Ox shows the highest ketonization activity at 340°C for 12 h, achieving maximum acetone yield of 88.27%; and all catalysts exhibited selectivity higher than 96.75%. Apparent activation energy and acid reaction order are 161.2 kJ mol−1 and 0.70, respectively. Results suggest high ketonization activity of poorly crystallized tetragonal ZrO2. Addition of Mn results in ZrO2/MnOx solid solution and improves active sites. Acid property and Mn4+ content are important factors, and oxygen vacancy demonstrates relationship with ketonization activity for ZrO2. Examination of recovered catalysts indicates that ZrMnyOx exhibits improved stability, and Mn leaching and crystal phase transformation are main causes of deactivation in aqueous-phase ketonization. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2958–2967, 2017
      PubDate: 2017-03-02T00:55:43.689402-05:
      DOI: 10.1002/aic.15687
       
  • Removal of NO from flue gas using UV/S2 O82− process in a novel
           photochemical impinging stream reactor
    • Authors: Yangxian Liu; Jun Zhang
      Pages: 2968 - 2980
      Abstract: A novel photochemical impinging stream reactor was developed for the first time. Removal process of NO from flue gas using sulfate radical (SO4−·) and hydroxyl radical (·OH) from UV-light activation of persulfate (UV/S2O82 advanced oxidation process) was investigated in the novel reactor. Experiments were conducted to evaluate the effects of S2O82− concentration, solution pH, UV power, solution temperature, liquid-gas ratio, flue gas flow, NO, SO2,and O2 concentrations on removal of NO. Mechanism and kinetics of NO removal were also studied. The results show that increasing UV power, solution temperature, S2O82− concentration, or solution circulation rate promotes NO removal. Increasing solution pH (1.2–11.9), NO concentration or flue gas flow weakens NO removal. O2 concentration has no significant effect on NO removal. SO4−· and ·OH were the major active species for NO removal. Absorption rate equation and kinetic parameters of NO removal were obtained. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2968–2980, 2017
      PubDate: 2017-01-22T16:00:42.90954-05:0
      DOI: 10.1002/aic.15633
       
  • Novel method for determination of gas solubilities in low vapor pressure
           liquids
    • Authors: L. F. Zubeir; P. J. L. Lipman, J. van der Schaaf, N. Awwad, C. J. Peters, M. C. Kroon
      Pages: 2981 - 2986
      Abstract: A modified version of a standard device for measuring gas adsorption and desorption isotherms and surface area of adsorbents and catalysts (ASAP (Accelerated Surface Area and Porosimetry System) 2020, Micromeritics USA) is used for the first time to measure gas solubilities (i.e., CO2) in low vapor pressure liquids (i.e., the IUPAC standard ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C6mim][Tf2N])) in the Henry's law region. The solubility data are in very good agreement with the reported data in literature. Furthermore, the Henry's law constants are calculated from the solubility data and compared to the experimental data found in literature. The results from this study demonstrate that Micromeritics ASAP 2020 is a suitable apparatus for gas absorption by solvents with reduced vapor pressures. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2981–2986, 2017
      PubDate: 2017-01-25T16:00:33.451239-05:
      DOI: 10.1002/aic.15603
       
  • Integrated adsorbent-process optimization for carbon capture and
           concentration using vacuum swing adsorption cycles
    • Authors: Maninder Khurana; Shamsuzzaman Farooq
      Pages: 2987 - 2995
      Abstract: A novel approach for integrated adsorbent and process design is proposed. The traditional pressure or vacuum swing adsorption (PSA) / vacuum swing adsorption (VSA) process optimization for chosen objectives, where operating conditions are the decision variables, and CO2 purity and recovery are constraints, is expanded to include adsorbent isotherm characteristics as additional decision variables. Two VSA cycles, namely a four-step process1, currently known to have the lowest energy consumption for CO2 capture and concentration (CCC), and a six-step process2, recently proven to have a wider operating window for the evacuation pressure, have been investigated in the current study. The integrated optimization results simultaneously provide the lower bound of minimum energy and upper bound of maximum productivity for CCC achievable from the two VSA processes along with the operating conditions and the corresponding isotherm shapes necessary to achieve them. It may be viewed as an enabler for adsorbent design or expedient adsorbent search by process inversion. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2987–2995, 2017
      PubDate: 2017-01-26T13:05:59.812932-05:
      DOI: 10.1002/aic.15602
       
  • Investigation of CO2 removal by immobilized carbonic anhydrase enzyme in a
           hollow-fiber membrane bioreactor
    • Authors: Ion Iliuta; Maria C. Iliuta
      Pages: 2996 - 3007
      Abstract: Gas–liquid membrane contactors are compelling candidate bioreactors for implementing CO2 capture because of large mass transfer rates and liquid–solid interfaces, low pressure drop, low axial dispersion and mixing, modularity, simple scale-up or scale-down, and operational suppleness. Binding the carbonic anhydrase (CA) enzyme on the membrane surface adds extra advantages due to the impressive large hydration turnover number and offers an attractive way for CO2 capture. This novel approach to CO2 removal by immobilized CA in a hollow-fiber membrane bioreactor (HFMB) was investigated via a multiscale steady-state model, under gas-filled and partially liquid-filled membrane pores conditions. The impact of CA loading, buffer acid-base constant and concentration, membrane wetting, uncatalyzed/catalyzed CO2 hydration in the wetted membrane zone, operating conditions, and cocurrent/countercurrent flow orientation on the HFMB performance was analyzed. The results showed that this low-cost, green, and environmentally friendly technology could be an appealing alternative to CO2 capture from stationary emissions sources. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2996–3007, 2017
      PubDate: 2017-01-26T12:25:33.7182-05:00
      DOI: 10.1002/aic.15646
       
  • Highly efficient and reversible CO2 capture by tunable
           anion-functionalized macro-porous resins
    • Authors: Xi He; Ke Mei, Rina Dao, Jingsong Cai, Wenjun Lin, Xueqian Kong, Congmin Wang
      Pages: 3008 - 3015
      Abstract: Anion functionalized strategy has been proposed for the synthesis of macro-porous resins [IRA-900][An] through the neutral reaction of the basic resin [IRA-900][OH] with the corresponding donors. Combining CO2 adsorption results and FT-IR, solid-state 13C NMR characterization as well as quantum chemical calculations, chemical adsorption mechanism was verified and tunable capture of CO2 was realized. Among them, the anion functionalized resin [IRA-900][Triz] exhibits an extremely high adsorption capacity (4.02 mmol g−1 at 25°C, 0.15 bar), outperforming many other good adsorbents. Finally, we discuss the thermostability and recycling stability of [IRA-900][Triz], which shows a great potential in the industrial capture of CO2. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3008–3015, 2017
      PubDate: 2017-01-27T11:35:35.418457-05:
      DOI: 10.1002/aic.15647
       
  • Highly efficient removal of bulky tannic acid by millimeter-sized
           nitrogen-doped mesoporous carbon beads
    • Authors: Yanping Chong; Ke Liu, Yu Liu, Jitong Wang, Wenming Qiao, Licheng Ling, Donghui Long, Zhishan Bai
      Pages: 3016 - 3025
      Abstract: Millimeter-sized nitrogen-doped mesoporous carbon beads (NMCBs) with a controllable nitrogen content are synthesized for the first time via a suspension-polymerization assisted hard templating method. In contrast to conventional activated carbons, NMCBs exhibit outstanding structural advantages, including macroscopic morphology, a developed mesoporous structure and enriched surface chemistry. When used as adsorbents for the removal of the bulky organic pollutant tannic acid, these NMCBs demonstrated fast adsorption kinetics and very high adsorption capacity. The adsorption capacity strongly depends on the nitrogen content doped into the carbon framework. At a nitrogen content of 4.1 wt %, the adsorption capacity reaches 318 mg g−1. The molecular mechanics simulation and zeta potential measurements suggest that the enhanced adsorption by nitrogen doping may be due to the electrostatic attraction between the nitrogen functional groups and the phenol groups of tannic acid. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3016–3025, 2017
      PubDate: 2017-01-31T15:15:39.54327-05:0
      DOI: 10.1002/aic.15601
       
  • Hydrogen separation at elevated temperatures using metallic nickel hollow
           fiber membranes
    • Authors: Mingming Wang; Jian Song, Yuan Li, Xiaoyao Tan, Yuanyuan Chu, Shaomin Liu
      Pages: 3026 - 3034
      Abstract: Nickel is a cheaper metallic material compared to palladium membranes for H2 separation. In this work, metallic Ni hollow fiber membranes were fabricated by a combined phase inversion and atmospheric sintering method. The morphology and membrane thickness of the hollow fibers was tuned by varying the spinning parameters like bore liquid flow rate and air gap distance. H2 permeation through the Ni hollow fibers with N2 as the sweep gas was measured under various operating conditions. A rigorous model considering temperature profiles was developed to fit the experimental data. The results show that the hydrogen permeation flux can be well described by using the Sieverts’ equation, implying that the membrane bulk diffusion is still the rate-limiting step. The hydrogen separation rate in the Ni hollow fiber module can be improved by 4–8% when switching the co-current flow to the countercurrent flow operation. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3026–3034, 2017
      PubDate: 2017-01-31T11:34:48.730335-05:
      DOI: 10.1002/aic.15652
       
  • Modeling the membrane formation of novel PVA membranes for predicting the
           composition path and their final morphology
    • Authors: Denis Bouyer; Oualid M'Barki, Céline Pochat-Bohatier, Catherine Faur, Eddy Petit, Patrick Guenoun
      Pages: 3035 - 3047
      Abstract: Herein, a numerical model is developed for investigating the appropriate operating conditions for obtaining porous membranes from PVA/water system. The main interest of such novel polymeric system lies in the use of water as solvent instead of classical organic solvent. In that context, the membrane formation involves three coupled and interdependent phenomena: phase inversion, crosslinking, and solvent evaporation. The mass transfer model involves thermodynamic description by Flory-Huggins theory, specific diffusion formalism for dilute system and external mass transfers in free convection. Since the system evolves from monophasic to diphasic region during membrane formation, the diffusion formalisms were adjusted depending on the composition path to simulate the solvent and catalyzer evaporation. The simulations exhibit that due to mass transfers occurring concomitantly to phase inversion and crosslinking, the operating conditions (final temperature, catalyzer, initial solution thickness) must be carefully chosen to ensure the formation of a porous membrane with PVA/water system. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3035–3047, 2017
      PubDate: 2017-02-13T12:20:33.534537-05:
      DOI: 10.1002/aic.15670
       
  • Mass transfer performance and correlations for CO2 absorption into aqueous
           blended of DEEA/MEA in a random packed column
    • Authors: Hongxia Gao; Bin Xu, Liang Han, Xiao Luo, Zhiwu Liang
      Pages: 3048 - 3057
      Abstract: The mass transfer performance of CO2 absorption into blended N,N-diethylethanolamine (DEEA)/ethanolamine (MEA) solutions was investigated using a lab-scale absorber (H = 1.28 m, D = 28 mm) packed with Dixon ring random packing. The mass transfer coefficient KGav, the unit volume absorption rate Φ, outlet concentration of CO2 (yCO2), and the bottom temperature Tbot of CO2 in aqueous DEEA/MEA solutions were determined over the feed temperature range of 298.15–323.15 K, lean CO2 loading of 0.15–0.31 mol/mol, over a wide range of liquid flow rate of 3.90–9.75 m3/m2-h, by using inert gas flow rate of 26.11–39.17 kmol/m2-h and 6–18 kPa CO2 partial pressure. The results show that liquid feed temperature, lean CO2 loading, liquid flow rate, and CO2 partial pressure had significant effect on those parameters. However, the inert gas flow rate had little effect. To allow the mass transfer data to be really utilized, KGav and yout correlations for the prediction of mass transfer performance were proposed and discussed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3048–3057, 2017
      PubDate: 2017-02-22T09:40:27.040091-05:
      DOI: 10.1002/aic.15673
       
  • Column absorption for reproducible cyclic separation in small scale
           ammonia synthesis
    • Authors: Kevin Wagner; Mahdi Malmali, Collin Smith, Alon McCormick, E. L. Cussler, Ming Zhu, Nicholas C. A. Seaton
      Pages: 3058 - 3068
      Abstract: Ammonia is rapidly and reversibly absorbed on magnesium chloride supported on alumina. The absorption at ambient temperature is twice that on alumina alone, but much of the ammonia is still captured at 400°C, closer to the temperature of ammonia synthesis. Regeneration at 450°C is complete in 30 min; partial regeneration is faster, and is correlated with the temperature and the regeneration time. The supported absorbent column works for many cycles, reproducibly, because submicron-sized MgCl2 crystals are trapped in similarly sized pores in the alumina itself, and the confinement prevents deterioration of the microstructure during absorption or regeneration. In contrast, while ammonia absorption into pure magnesium chloride is potentially much larger at equilibrium, the ammonia absorbs very slowly, and the chloride loses available capacity with use, probably because of fusing and deterioration of microstructure. A simplified model was constructed to simulate ammonia absorption into pure magnesium chloride and alumina-supported magnesium chloride. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3058–3068, 2017
      PubDate: 2017-02-28T12:15:33.342838-05:
      DOI: 10.1002/aic.15685
       
  • Effect of the presence of organic matter on bubble points of oils in
           shales
    • Authors: Manas Pathak; Palash Panja, Raymond Levey, Milind Deo
      Pages: 3083 - 3095
      Abstract: The relative amounts of oil and gas produced in prolific plays like the Eagle Ford are affected by the oil bubble point. The oil and kerogen (organic matter) are found in the same rock and the oil may remain in contact with the kerogen. Bulk experiments and molecular simulations clearly show that kerogen preferentially absorbs hydrocarbons. The absorbed oil phase remains in multi-component equilibrium with the expelled oil produced at the surface. Results from a model proposed to calculate the bubble points (at 400 K) of in situ oils (absorbed + free) in the presence of kerogen indicate suppression of about 4150–16,350 kPa from the original value of 28,025 kPa of produced Eagle Ford oil. These calculations depend on the type and level of maturity of kerogen. The prediction of accurate saturation pressures has key implications on volumes of recovery and rates of production from liquid rich shales. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3083–3095, 2017
      PubDate: 2017-01-24T10:25:29.909014-05:
      DOI: 10.1002/aic.15635
       
  • Prediction and screening of solubility of pharmaceuticals in single- and
           mixed-ionic liquids using COSMO-SAC model
    • Authors: Bong-Seop Lee; Shiang-Tai Lin
      Pages: 3096 - 3104
      Abstract: In this work, we investigated the prediction of solubility (xd) of drug molecules in single- and mixed-ionic liquid (IL) solutions using the COSMO-SAC activity coefficient model. In particular, the effect of dissociation of IL on solubility is examined. The prediction accuracy is found to be 91% in xd (root-mean-square deviation in ln xd is 0.65) for a total of 442 data points with solubility ranging from 0.93 to 2.84 × 10−4 (mole fraction) and temperature ranging from 248.9 to 488.3 K. The solubility of drug is found not sensitive to the treatment of dissociation of IL in the calculations. The method is used to determine the solubility of paracetamol in 2624 single IL made from combination of 82 cations and 32 anions. The solubility of paracetamol can vary by 4 orders of magnitude in different ILs, indicating that this is a powerful method for screening for solvents with desired solubility power. The solubility of a drug in binary IL solution can be significantly higher or lower than those in pure IL components. For the 3,441,376 binary IL mixtures, about 8% of the mixtures exhibit higher solubility for paracetamol and 6% exhibit lower solubility. Our results indicate that mixing ILs can be a viable approach for tuning drug solubility. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3096–3104, 2017
      PubDate: 2017-01-25T16:00:42.705648-05:
      DOI: 10.1002/aic.15595
       
  • Design and construction of an equipment for the determination of
           solubility of gases in liquids
    • Authors: Luis C. A. Garzon; Carmen M. Romero, Andres F. Suarez
      Pages: 3105 - 3109
      Abstract: This article presents the design and construction of a new isochoric saturation apparatus for the determination of gas solubility in liquids based on the gas drop pressure method. The major improvement of this design is the separation between the solubility and the gas cells. With this separation, the change of pressure and temperature inside the system is minimum when the gas gets in contact with the liquid and it allows degassing the liquid in an easy way. The performance of the equipment was evaluated measuring the solubility of argon and nitrogen in pure water at 283.15, 288.15, 293.15, and 298.15 K. The gas solubility was calculated according to the Henry's law. The results obtained and the comparison with literature values show that the equipment provides an accurate and precise method for determination of gas solubility in water. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3105–3109, 2017
      PubDate: 2017-01-27T11:27:14.546396-05:
      DOI: 10.1002/aic.15637
       
  • Thermodynamic modeling of HNO3-H2SO4-H2O ternary system with symmetric
           electrolyte NRTL model
    • Authors: Meng Wang; Harnoor Kaur, Chau-Chyun Chen
      Pages: 3110 - 3117
      Abstract: The nitric acid concentration/sulfuric acid concentration (NAC/SAC) process has been widely used for concentrating dilute aqueous nitric acid and recovering spent sulfuric acid. Dilute nitric acid (65 to 80 wt %) is concentrated using sulfuric acid to bind water and break the nitric acid-water azeotrope at approximately 68 wt % nitric acid. To support heat and mass balance calculations and process simulation for NAC/SAC processes, we develop a comprehensive thermodynamic model for nitric acid-sulfuric acid-water ternary system based on previously published thermodynamic models of nitric acid-water and sulfuric acid-water binary systems with eNRTL equation. The ternary system model correlates well the isobaric vapor-liquid equilibrium data at one atmosphere and the water and nitric acid activities data at 273.15 K for the ternary. Contour plots of boiling points, vapor phase composition, and specific heat capacity of the ternary system, as well as a Merkel enthalpy-concentration chart are generated for engineering use. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3110–3117, 2017
      PubDate: 2017-02-28T12:15:28.850174-05:
      DOI: 10.1002/aic.15679
       
  • Pore-network modeling of particle retention in porous media
    • Authors: Hongtao Yang; Matthew T. Balhoff
      Pages: 3118 - 3131
      Abstract: Transport and filtration of micron and submicron particles in porous media is important in applications such as water purification, contaminants dispersion, and drilling mud invasion. Existing macroscopic models often fail to be predictive without empirical adjustments and a more fundamental approach may be required. We develop a physically-representative, 3D pore network model based on a particle tracking method to simulate particle retention and permeability impairment in polydisperse particle systems. The model includes the effect of hydraulic drag, gravity, electrostatic and van der Waals forces, as well as Brownian motion. A converging-diverging pore throat geometry is used to capture the mechanism of interception. With the analytical solution of fluid velocity within a pore throat, the trajectory of each particle is calculated explicitly. We also incorporate surface roughness and particle–surface interaction to determine particle attachment and detachment. Pore throat structure and conductivity are updated dynamically to account for the effect of deposited particles. Predictions of effluent concentration and macroscopic filtration coefficient are in good agreement with published experimental data. We find that the filtration coefficient is dependent on the relative angle between fluid flow and gravity. Particle deposition by interception is significant for large particle/grain size ratios. Brownian diffusion is the primary cause of retention at low Peclet numbers, especially for small gravity numbers. Particle size distribution is found to be a cause of hyperexponential deposition often observed in experiments. Permeability reduction was small for strong repulsive forces because particles only deposited in paths of slow velocity. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3118–3131, 2017
      PubDate: 2017-01-24T14:35:32.985511-05:
      DOI: 10.1002/aic.15593
       
  • The influence of injection velocity and relaxation time on the spreading
           of tracers in viscoelastic liquids agitated by submerged, recirculating
           jets with low reynolds numbers
    • Authors: Pradipto K. Bhattacharjee; Stephen P. Kennedy, Qian Xu, Nicky Eshtiaghi, Rajarathinam Parthasarathy
      Pages: 3132 - 3140
      Abstract: We provide experimental demonstration that the spread of tracer elements in a tank containing a viscoelastic liquid and agitated by a submerged jet pointing to the base of the tank can be influenced by the relaxation time of the liquid. We analyzed the temporal spreading of the boundary of a tracer-front in two dimensions using flow visualization at early stages and found that for a given fluid, the evolution of the tracer-front at various injection velocities follows a universal trajectory when considered on a normalized time scale of t/vN2/κ, where t is observation time, vN is injection velocity and κ is the effective diffusivity of the tracer elements in the medium. For a different fluid, at a given vN, the trajectory scales with the relaxation time of the fluid. The importance of relaxation time to the evolution of a tracer-front is something previously unreported. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3132–3140, 2017
      PubDate: 2017-01-24T10:20:28.959883-05:
      DOI: 10.1002/aic.15640
       
  • Mass and heat transfer behavior of oscillating helical coils in relation
           to heterogeneous reactor design
    • Authors: Mohamed Helmy Abdel-Aziz; Inderjit Nirdosh, Gomaa H. Sedahmed
      Pages: 3141 - 3149
      Abstract: Rates of mass and heat transfer at vibrating helical coils were studied by the electrochemical technique with the object of using helical coils as heat exchanger/reactor for conducting liquid–solid diffusion controlled reactions. Variables studied were frequency and amplitude of vibration, tube diameter, and superimposed axial flow velocity. The data for vibrating coil (batch reactor) were correlated for 59 
      PubDate: 2017-01-25T15:50:26.523068-05:
      DOI: 10.1002/aic.15614
       
  • Bouncing of a bubble at a liquid–liquid interface
    • Authors: K. K. Singh; F. Gebauer, H.-J. Bart
      Pages: 3150 - 3157
      Abstract: Significant industrial relevance of gas–liquid–liquid flows calls for understanding of their various aspects. This study focusing on one of the aspects, i.e., interaction of a single bubble with a liquid–liquid interface, is aimed at providing the experimental evidence of a hitherto unreported phenomenon of conditional bouncing of a bubble at the interface between two immiscible, initially quiescent liquids. Bouncing of the bubble is observed for two of the six pairs of the immiscible liquids used in the experiments. The data, obtained by conducting experiments with different pairs of the lighter and heavier liquid bubble diameters and rise heights, suggest that a bubble crossing a liquid–liquid interface is expected to bounce when its average velocity is less than a threshold value that depends on the interfacial tension between the two liquids and the viscosity of the heavier liquid. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3150–3157, 2017
      PubDate: 2017-01-27T11:27:17.773496-05:
      DOI: 10.1002/aic.15625
       
  • Arbitrary shaped ice particle melting under the influence of natural
           convection
    • Authors: Hemant Bansal; Petr Nikrityuk
      Pages: 3158 - 3176
      Abstract: This work is devoted to numerical simulations of an arbitrary shaped ice particle melting inside water under the influence of natural convection. Specifically, four different shapes of the ice particle have been studied: sphere, cylinder, cross shaped cylinder, and irregular sphere with radial bumps on its surface. A 2D axisymmetric particle-resolved numerical model has been employed on a fixed grid to study the detailed melting dynamics of an ice particle. The solid-liquid interface is treated as a porous medium characterized by the permeability coefficient which is used to damp the velocity values inside the interface. The model results have been compared with an existing experimental results produced by A. Shukla et al. (Metal Mater Trans B. 2011; 42(1):224–235). Very good agreement between our predictions and experimental data have been achieved. Based on the analysis of numerical simulation results, melting process is found to advance through two distinct regimes, namely, establishment of the natural convection and active melting of ice particle exhibiting substantial amount of fluid-particle interactions. A set of dimensionless parameters have been identified to distinguish between regimes. Finally, we developed a semi-empirical to predict the melting of any arbitrary shaped ice particle and validated it against the particle-resolved numerical simulation and experimental results. The comparison showed good agreement. Finally, the presented semi-empirical model can be used as sub-grid model in Euler-Lagrange based numerical models to study the phase change phenomena in particulate flow systems. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3158–3176, 2017
      PubDate: 2017-01-27T11:30:51.178875-05:
      DOI: 10.1002/aic.15643
       
  • Analysis of roll wave characteristics under low liquid loading two-phase
           flow conditions
    • Authors: Hamidreza Karami; Eduardo Pereyra, Cem Sarica, Carlos F. Torres
      Pages: 3177 - 3186
      Abstract: An experimental study is conducted using a 0.152-m ID facility to investigate the wave characteristics of two-phase stratified wavy flow in horizontal pipelines. The experiments are conducted under low liquid loading condition, which is very commonly observed in wet gas pipelines. The experiments are conducted with water as the liquid phase, and repeated with 51 wt % of monoethylene glycol (MEG) in the aqueous phase to analyze the effects of MEG presence on wave characteristics. The experimental range of this study covers superficial gas velocity, vSg, values of 9–23 m/s and superficial liquid velocity, vSL, values of 0.01–0.02 m/s. Similar test matrices are completed for the cases with and without MEG in the aqueous phase. A conductivity probe system is used to measure the wave characteristics at the liquid–gas interface. These characteristics include the wave celerity, frequency, amplitude, length, and liquid film thickness. The experimental oil–air wave characteristics data of Gawas et al. (Int J Multiphase Flow. 2014;63:93–104) is also used for comparison purposes. The trends in the resulting wave characteristics with respect to input parameters are investigated, for oil, water, or MEG–water mixture as the liquid phase. Common predictive methods for interfacial wave celerity, including shallow water theory, Watson (Proceedings of the 4th International Conference in Multi-Phase Flows, Nice, France. 1989:495–512), Paras et al. (Int J Multiphase Flow. 1994;20(5):939–956), Al-Sarkhi et al. (AIChE J. 2012;58(4):1018–1029), and Gawas et al. (Int J Multiphase Flow. 2014;63:93–104) are evaluated in comparison with the experimental data. The results of the wave frequency correlation of Al-Sarkhi et al. (AIChE J. 2012;58(4):1018–1029) are also compared with the experimental wave frequency data. Lastly, a correlation is developed to predict the relative wave amplitude, as a function of superficial gas Weber number and liquid velocity number. Most of the commonly used two-phase stratified flow models are developed with the assumption of steady-state conditions, and neglect the transient wave effects. This study provides valuable experimental results on wave characteristics of stratified wavy flow for different types of liquid phase. Moreover, a comprehensive analysis of the parameters affecting the wave characteristics of stratified wavy flow is presented. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3177–3186, 2017
      PubDate: 2017-02-02T13:35:48.542377-05:
      DOI: 10.1002/aic.15650
       
  • Particle migration and alignment in slot coating flows of elongated
           particle suspensions
    • Authors: Ivan R. Siqueira; Rodrigo B. Rebouças, Marcio S. Carvalho
      Pages: 3187 - 3198
      Abstract: We analyze slot coating flows of elongated particle suspensions and investigate particle concentration and average orientation at the coated film. Shear-induced particle migration is described by the Diffusive Flux Model, and particle orientation is given by the principal direction of the particle conformation tensor. The conformation evolution and the constitutive equation for the resulting complex liquid are adapted from classical models that describe the behavior of suspensions of cylinders and fibers and polymeric solutions of almost rigid rod-like molecules. The proposed fully coupled model is applied to slot coating flows, and is solved using the DEVSS-TG/SUPG finite element method. The results show that the wet coated film is highly nonuniform. Particle concentration and orientation vary along the film thickness and are a strong function of the operating parameters of the process, such as the film thickness-to-coating gap ratio and the capillary number of the flow. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3187–3198, 2017
      PubDate: 2017-02-03T11:15:35.692711-05:
      DOI: 10.1002/aic.15653
       
  • Computational fluid dynamics-based steam cracking furnace optimization
           using feedstock flow distribution
    • Authors: Yu Zhang; Pieter A. Reyniers, Carl M. Schietekat, Kevin M. Van Geem, Guy B. Marin, Wenli Du, Feng Qian
      Pages: 3199 - 3213
      Abstract: Nonuniform temperature fields in steam cracking furnaces caused by geometry factors such as burner positions, shadow effects, and asymmetry of the reactor coil layout are detrimental for product yields and run lengths. The techniques of adjusting burner firing (zone firing) and feedstock mass flow rate (pass balancing) have been practiced industrially to mitigate these effects but could only reduce the nonuniformities between the so-called modules (a group of many coils). An extension of the pass balancing methodology is presented to further minimize the intra-module nonuniformities, that is, variation between the coils within a module, in floor fired furnaces. Coupled furnace-reactor computational fluid dynamics-based simulations of an industrial ultraselective conversion (USC) furnace were performed to evaluate four different feedstock flow distribution schemes, realizing equal values for coil outlet temperature, propene/ethene mass ratio, maximum coking rate and maximum tube metal temperature (TMT), respectively, over all the reactor coils. It is shown that feedstock flow distribution creates a larger operating window and extends the run length. Out of the four cases, the coking rate as criterion leads to the highest yearly production capacity for ethene and propene. Uniform maximum coking rates boost the annual production capacity of the USC furnace with a nameplate ethene capacity of 130 103 metric tons per year with 1000 metric tons for ethene and 730 metric tons for propene. For industrial application, achieving uniform maximum TMT is more practical due to its measurability by advanced laser-based techniques. Most steam cracking furnaces can be retrofitted by optimizing the dimensions of venturi nozzles that regulate the feedstock flow to the coils. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3199–3213, 2017
      PubDate: 2017-02-18T15:45:35.518555-05:
      DOI: 10.1002/aic.15669
       
  • Equilibrium and non-equilibrium gas–liquid two phase flow in long and
           short pipelines following a rupture
    • Authors: A. Nouri-Borujerdi; A. Shafiei Ghazani
      Pages: 3214 - 3223
      Abstract: The two-phase flow following the blowdown of pipeline carrying flashing liquid is numerically investigated by using thermodynamic equilibrium and non-equilibrium models. Model equations are solved numerically by the finite volume method. The values of fluxes at cell boundaries are obtained by AUSM+-up. To obtain proper values for the coefficients of dissipation, both single phase liquid and two phase shock tube problems are investigated. The transient release from the pressurized pipeline is studied for two cases of long and short pipes. Comparison of the predictions against experimental data reveals non-equilibrium model performs a little better than equilibrium model in the prediction of temporal variations of pressure and void fraction of the long pipe. However, equilibrium model totally overestimates pressure and void fraction of the short pipe. The relative error of equilibrium model in the prediction of pressure variation with time exceeds 50% and it is 20% for non-equilibrium model. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3214–3223, 2017
      PubDate: 2017-02-25T07:35:29.004995-05:
      DOI: 10.1002/aic.15675
       
  • Real gas transport in tapered noncircular nanopores of shale rocks
    • Authors: Jinze Xu; Keliu Wu, Sheng Yang, Jili Cao, Zhangxin Chen, Yi Pan, Bicheng Yan
      Pages: 3224 - 3242
      Abstract: A model for gas transport in tapered noncircular nanopores of shale rocks with integrating real gas effect, molecular kinetic, and transport behavior was presented. The proposed model is well validated with experimental and simulation data, including six kinds of gases, under different pressures, and temperatures. Results show that neglect of real gas effect results in the misleading transport conductance. The adsorbed gas transport ratio and the ratio of area occupied by adsorbed gas increase along the length of nanopore. Pore proximity induces the faster gas transport and omitting pore proximity leads to the enlargement of the adsorbed gas-dominated region. Increasing taper ratio (ratio of inlet size to outlet size) and aspect ratio weakens real gas effect and lowers free gas transport. Moreover, it lowers the total transport capacity of the nanopore, and the tapered circular nanopore owns the greatest transport capacity, followed by tapered square, elliptical, and rectangular nanopores. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3224–3242, 2017
      PubDate: 2017-03-02T00:46:57.150396-05:
      DOI: 10.1002/aic.15678
       
 
 
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