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  Subjects -> ENGINEERING (Total: 2281 journals)
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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     Hybrid Journal   (Followers: 6)
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: 233)
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: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 7)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
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: 15)
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: 21)
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: 41)
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: 30)
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: 15)
Applied Clay Science     Hybrid Journal   (Followers: 5)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
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)
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: 5)
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: 4)
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: 10)
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: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 9)
Biomedical Science and Engineering     Open Access   (Followers: 4)
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: 8)
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: 8)
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: 10)
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: 5)
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: 26)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 257)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 181)
Composites Part B : Engineering     Hybrid Journal   (Followers: 237)
Composites Science and Technology     Hybrid Journal   (Followers: 216)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 14)
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: 30)
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: 9)
Control Engineering Practice     Hybrid Journal   (Followers: 42)
Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Current Science     Open Access   (Followers: 58)

        1 2 3 4 5 6 7 | Last

Journal Cover AIChE Journal
  [SJR: 1.122]   [H-I: 120]   [30 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  [1577 journals]
  • A Theory of Ultra-Deep Hydrodesulfurization of Diesel in Stacked-Bed
    • Authors: Teh C. Ho
      Abstract: Hydrodesulfurization catalysts have two types of active sites for hydrogenation and hydrogenolysis reactions. While hydrogenation sites are more active for desulfurizing refractory sulfur species, they are more susceptible to organonitrogen inhibition than hydrogenolysis sites. In contrast, hydrogenolysis sites are more resistant to organonitrogen inhibition but are less active for desulfurizing refractory sulfur species. This dichotomy is exploited to develop an ultra-deep hydrodesulfurization stacked-bed reactor comprising two catalysts of different characteristics. The performance of such a catalyst system can be superior or inferior to that of either catalyst alone. A mathematical model is constructed to predict the optimum stacking configuration for maximum synergies between the two catalysts. The best configuration provides the precise environment for the catalysts to reach their full potentials, resulting in the smallest reactor and minimum hydrogen consumption. Model predictions are consistent with experimental results. A selectivity-activity diagram is developed for guiding the development of stacked-bed catalyst systems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-16T10:55:28.438511-05:
      DOI: 10.1002/aic.15969
  • A Multicontinuum Approach for the Problem of Filtration of Oily-Water
           Systems across Thin Flat Membranes: II. Validation and Examples
    • Authors: Amgad Salama; Mohamed Zoubeik, Amr Henni
      Abstract: In this second part, a validation exercise is conducted to investigate the accuracy of the multicontinuum approach in estimating the permeation capacity of membranes used for the filtration of oily-water systems. Comparisons with the experimental works found in the literature reveals that the multi-continuum approach is quite accurate and show excellent match. Although the comparisons with the experimental data have been with respect to macroscopic integral variables, like the rejection capacity of membranes, the multi-continuum approach provides myriad information about the permeation process that have neither been presented nor even measured. Such detailed information has been highlighted in two examples. Details about which of the oil continua is going to be rejected or permeated through which porous membrane continuum are obtained. Furthermore, the flux of each oil continuum through every porous membrane continua are likewise obtained. These information are then lumped to calculate the rejection capacity of membranes. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-16T10:55:25.689633-05:
      DOI: 10.1002/aic.15970
  • A pinch-like targeting framework for systematic thermal process
    • Authors: Michael Baldea
      Abstract: The design of intensified systems remains an “Edisonian” effort, whereby new intensification schemes are the product of creativity rather than the result of applying systematic procedures. Under this motivation, this paper presents a novel and systematic approach for identifying targets for thermal process intensification (defined as combining two or more heat sources and sinks present in a process flowsheet, possibly along with a thermal utility stream, in a single intensified device where heat exchange takes place. The targeting problem is formulated as a mixed-integer linear program (MILP). An extensive case study illustrating its application is presented. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-16T10:55:21.254673-05:
      DOI: 10.1002/aic.15971
  • Dissipative Particle Dynamic Simulation on the Assembly and Release of
           siRNA/Polymer/Gold Nanoparticles Based Polyplex
    • Authors: Xiaona Xie; Shouping Xu, Pihui Pi, Jiang Cheng, Xiufang Wen, Xuan Liu, Shengnian Wang
      Abstract: Dissipative particle dynamics (DPD) simulation is used to reveal the loading/release of small interfering RNA (siRNA) in pH-sensitive polymers/gold nanoparticles (AuNPs) polyplex. The conformation dynamics of these polyplex at various Au/siRNA mass ratios, the original AuNPs sizes, polymer types, and pH values are simulated and compared to experimental results. At neutral conditions (pH=7.4), spherical micelles with a multilayer structure are formed in siRNA/polyethyleneimine/cis-aconitic anhydride functionalized poly(allylamine)/polyethyleneimine/11-mercaptoundecanoic acid-gold nanoparticle (siRNA/PEI/PAH-Cit/PEI/MUA-AuNP) polyplex. Large polyplex are obtained with high Au/siRNA mass ratio and/or small original AuNPs size. The release dynamics of siRNA from AuNPs-polyplex systems were also simulated in the intracellular environment (pH=5.0). A swelling-demicellization-releasing mechanism is followed while the release of siRNA is found much faster for polyplex involving charge-reversal PAH-Cit. These findings are qualitatively consistent with the experimental results and may provide valuable guidance in later design and optimization of delivery carriers for siRNA or other molecule probes. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-11T11:21:19.364479-05:
      DOI: 10.1002/aic.15961
  • A flowsheet model for the development of a continuous process for
           pharmaceutical tablets – an industrial perspective
    • Authors: Salvador García-Muñoz; David Slade, Adam Butterbaugh, Ian Leavesley, Leo Francis Manley, Sean Bermingham
      Abstract: A dynamic model of a continuous direct compression process for pharmaceutical tablets is presented. The objective is to assess the impact of the variability from the feeder system on the concentration of drug in the powder in the feed frame of a tablet press. The model is based on principles of dispersed flow from the reaction engineering field. An estimability analysis was performed to understand the impact of the available measurements on the estimated parameters and suggest better ways to approach the parametrization. Predictions are successfully contrasted with experimental data. The model is used to produce residence time distributions at different process conditions and a graphical representation of the allowable range of disturbances in the feeders that can be mitigated by the process. The model was used in support of the method development for an on-line near infra-red sensor. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-11T11:15:49.984299-05:
      DOI: 10.1002/aic.15967
  • Target Bounds on Reaction Selectivity via Feinberg's CFSTR Equivalence
    • Authors: Jeffrey A. Frumkin; Michael F. Doherty
      Abstract: In this work, we show that the Continuous Flow Stirred Tank Reactor (CFSTR) Equivalence Principle, developed by Feinberg and Ellison,1 can be used to obtain practical upper bounds on reaction selectivity for any chemistry of interest. The CFSTR Equivalence Principle allows one to explore the attainable reaction region by decomposing any arbitrary, steady-state reactor-mixer-separator system with total reaction volume V > 0 into a new system comprising R + 1 CFSTRs (where R is the number of linearly independent chemical reactions) with the same total reaction volume and a perfect separator system. [1, 2] This work further refines the allowable selectivities by incorporating capacity constraints into the CFSTR Equivalence Principle to prevent arbitrarily large recycle streams between the CFSTRs and the separators and infinitesimally small CFSTR conversions. These constraints provide practical upper bounds on reaction selectivities of chemistries completely independent of reactor design. We present the methodology and the results for a selection of realistic chemistries. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-11T11:15:42.2626-05:00
      DOI: 10.1002/aic.15968
  • Reversible Cluster Aggregation and Growth Model for Graphene Suspensions
    • Authors: Michail Alifierakis; Kevin S. Sallah, Jean H. Prévost, Ilhan A. Aksay
      Abstract: We present a reversible cluster aggregation model for 2-dimensional macromolecules represented by line segments in 2-dimensions; and, we use it to describe the aggregation process of functionalized graphene particles in an aqueous SDS surfactant solution. The model produces clusters with similar sizes and structures as a function of SDS concentration in agreement with experiments and predicts the existence of a critical surfactant concentration (Ccrit) beyond which thermodynamically stable graphene suspensions form. Around Ccrit, particles form dense clusters rapidly and sediment. At C ≪ Ccrit, a contiguous ramified network of graphene gel forms which also densifies, but at a slower rate, and sediments with time. The deaggregation-reaggregation mechanism of our model captures the restructuring of the large aggregates towards a graphite-like structure for the low SDS concentrations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-11T11:11:05.074495-05:
      DOI: 10.1002/aic.15962
  • A Systematic Method to Synthesize All Dividing Wall Columns for
           n-component Separation - Part II
    • Authors: Gautham Madenoor Ramapriya; Mohit Tawarmalani, Rakesh Agrawal
      Abstract: We present a simple rule that, for the first time, enables exhaustive enumeration of dividing wall columns (DWCs) corresponding to any given thermally coupled distillation column-configuration. With the successive application of our rule, every partition in a DWC can be extended all the way to the top and/or to the bottom of a column without losing thermodynamic equivalence to the original thermally coupled configuration. This leads to easy-to-operate DWCs with possible control/regulation of each and every vapor split by external means. As a result, we conclude that any given DWC can be transformed into a thermodynamically equivalent form that is easy-to-operate, and hence, there always exists at least one easy-to-operate DWC for any given thermally coupled distillation. Our method of enumerating and identifying easy-to-operate DWCs for an attractive thermally coupled configuration will contribute towards process intensification by providing ways to implement efficient and low-cost multicomponent distillations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-09T10:45:25.110804-05:
      DOI: 10.1002/aic.15963
  • Spontaneous Imbibition of Liquids in Glass-Fiber Wicks. Part I: Usefulness
           of a Sharp-Front Approach
    • Authors: M. Amin F. Zarandi; Krishna M Pillai, Adam S. Kimmel
      Abstract: Spontaneous imbibition of a liquid into glass-fiber wicks is modeled using the single-phase Darcy's law after assuming a sharp flow-front marked by full saturation behind the front occurring in a transversely-isotropic porous medium. An analytical expression for the height of the wicking flow-front as a function of time is tested through comprehensive experiments involving using eight different wicks and one oil as the wicking liquid. A good fit with experimental data is obtained without using any fitting parameter. The contact-angle is observed to be important for the success of the model—lower contact angle cases marked by higher capillary pressures were predicted the best. The proposed model provides a nice upper bound for all the wicks, thereby establishing its potential as a good tool to predict liquid absorption in glass-fiber wicks. However, the sharp-front model is unable to explain region of partial saturation, thereby necessitating the development of part II of this paper series 1 using Richard's equation This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-09T10:35:37.036253-05:
      DOI: 10.1002/aic.15965
  • Co-Production of Acetic Acid and Hydrogen/Power from Natural Gas with Zero
           Carbon Dioxide Emissions
    • Authors: Ibubeleye Somiari; Vasilios Manousiouthakis
      Abstract: In this work, a process plant flowsheet that co-produces acetic acid and hydrogen/power from natural gas with zero carbon dioxide emissions is developed. Two cases are explored: the production of acetic acid and hydrogen (case 1) and the production of acetic acid and power (case 2). This is realized by the selection of an appropriate reaction cluster whose sum results in the overall reaction that co-produces acetic acid and hydrogen/power. The concept of energetic self-sufficiency is introduced and it imposes constraints on the system defined in terms of the ratio of oxygen feed to acetic acid produced. Heat and power integration of the converged flowsheet reveals an operating range for each case that guarantees energetic self-sufficiency. Operating points are chosen to conduct a preliminary economic analysis and a carbon dioxide cost and performance metric calculation to quantify profitability and carbon capture potential of the overall process. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-09T10:35:31.074333-05:
      DOI: 10.1002/aic.15966
  • A Systematic Method to Synthesize All Dividing Wall Columns for
           n-Component Separation - Part I
    • Authors: Gautham Madenoor Ramapriya; Mohit Tawarmalani, Rakesh Agrawal
      Abstract: We present an easy-to-use stepwise procedure to synthesize an initial-dividing wall column (i-DWC) from any given n-component basic distillation column-sequence or its thermally coupled derivative. The procedure to be used is dependent on the nature of the distillation column-sequence that is to be converted into a DWC, and comprises of an intuitive set of steps that we demonstrate through examples. It is noteworthy that, even for a ternary distillation, fifteen potentially useful DWCs, some of which had been missing from the literature, have now been identified. This work significantly expands the search space of useful DWCs to separate any given multicomponent mixture. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-09T10:35:22.976856-05:
      DOI: 10.1002/aic.15964
  • Flow of Viscoelastic Surfactants through Porous Media
    • Authors: S. De; M. Golombok, S.P. Koesen, R.V. Maitri, J.T. Padding, J.F.M. van Santvoort
      Abstract: We compare the flow behavior of viscoelastic surfactant (VES) solutions and Newtonian fluids through two different model porous media having similar permeability: (a) a 3D random packed bed and (b) a microchannel with a periodically spaced pillars. The former provides much larger flow resistance at the same apparent shear rate compared to the latter. The flow profile in the 3D packed bed cannot be observed since it is a closed system. However, visualization of the flow profile in the microchannel shows strong spatial and temporal flow instabilities in VES fluids appear above a critical shear rate. The onset of such elastic instabilities correlates to the flow rate where increased flow resistance is observed. The elastic instabilities are attributed to the formation of transient shear induced structures. The experiments provide a detailed insight into the complex interplay between the pore scale geometry and rheology of VES in the creeping flow regime. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-09T10:30:26.413062-05:
      DOI: 10.1002/aic.15960
  • Flow Field Design and Optimization of High Power Density Vanadium Flow
           Batteries: a Novel Trapezoid Flow Battery
    • Authors: Meng Yue; Qiong Zheng, Feng Xing, Huamin Zhang, Xianfeng Li, Xiangkun Ma
      Abstract: Vanadium flow battery (VFB) is one of the preferred techniques for efficient large-scale energy storage applications. The key issue for its commercialization is cost reduction, which can be achieved by developing high power density VFB stacks. One of the effective strategies for developing high power density stacks is to enhance the mass transport by performing flow field design. Based on the maldistribution characteristics of concentration polarization inside a conventional rectangular flow battery (RFB), a novel trapezoid flow battery (TFB) was firstly proposed. Furthermore, a practical and general strategy, consisting of a stepping optimization method and an arithmetic progression model, has been developed for the TFB's structure optimization. By combining numerical simulation with charge-discharge test of the magnified stacks, it was verified that mass transport enhancement and performance improvement of the optimized TFB, with significant increments in voltage efficiency and electrolyte utilization, allowed it to possess great superiority over the RFB. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-09T10:30:21.929485-05:
      DOI: 10.1002/aic.15959
  • Modular Methanol Manufacturing from Shale Gas: Techno-economic and
           Environmental Analyses of Conventional Large-scale Production versus
           Small-scale Distributed, Modular Processing
    • Authors: Minbo Yang; Fengqi You
      Abstract: This paper presents comparative techno-economic and environmental analyses of four representative shale gas monetization options, namely, conventional shale gas processing, large-scale methanol manufacturing, modular methanol manufacturing with shale gas supplied by pipelines, and modular methanol manufacturing with consideration of plant relocation. We first present shale gas supply models for the four gas monetization options. Next, the process designs for shale gas processing and methanol manufacturing from shale gas are described. We develop detailed process simulation models for shale gas processing and methanol manufacturing with different scales using raw shale gas extracted from the Marcellus, Eagle Ford, and Bakken shale plays. On this basis, techno-economic analyses and environmental impact analyses are conducted for the four shale gas monetization options to systematically compare their economic and environmental performances based on the same conditions. The results show that modular methanol manufacturing is more economically competitive than conventional shale gas processing, although it leads to higher environmental impacts. Besides, modular methanol manufacturing is better than large-scale methanol manufacturing for raw shale gas produced from distributed, remote wells from both economic and environmental perspectives. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-07T10:40:29.957529-05:
      DOI: 10.1002/aic.15958
  • Novel Semi-interpenetrating Network Structural Phase Change Composites
           with High Phase Change Enthalpy
    • Authors: Yuang Zhang; Jinghai Xiu, Bingtao Tang, Rongwen Lu, Shufen Zhang
      Abstract: High phase change enthalpy, controllable temperature, and stable shape can expand the application of phase change materials (PCMs) in energy storage. In this study, a series of novel form-stable PCMs with high phase change enthalpy (169–195 J/g) and controllable temperature (45.3–61.4°C) were prepared. The PCMs exhibited a semi-interpenetrating polymer network (semi-IPN) structure resulting from the combination of polyethylene glycol and a 3D network gel. The gel itself featured an inherent phase change characteristic and a 3D network structure. Thus, it improved the phase transition enthalpy of the materials and facilitated the formation of a semi-IPN that endowed the materials with excellent form-stable properties. In addition, the latent heat of the composites (169–195 J/g) is much higher than most of the previously reported composites using PEG as phase change component (68–132 J/g). This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-07T01:45:41.598328-05:
      DOI: 10.1002/aic.15956
  • The Solubility of Gases in Ionic Liquids
    • Authors: Mark B. Shiflett; Edward J. Maginn, Mark B. Shiflett, Edward J. Maginn
      PubDate: 2017-09-06T16:35:27.546367-05:
      DOI: 10.1002/aic.15957
  • Issue information
    • Abstract: Cover illustration. Modular construction and modular production: a chemical plant can be constructed in the field from transportable modules (highlighted in color on the rightmost plant) that are fabricated in dedicated facilities, often thousands of miles away. Production capacity can be increased by deploying and operating in parallel multiple such modular facilities. Original photograph of modular distillation plant used with permission from Mr. Bill Stanley. 10.1002/aic.15872
      PubDate: 2017-09-04T11:09:28.362422-05:
      DOI: 10.1002/aic.15481
  • Adsorption Separation of R134a, R125 and R143a Fluorocarbon Mixtures Using
           13X and Surface Modified 5A Zeolites
    • Authors: Darshika K. J. A. Wanigarathna; Jiajian Gao, Bin Liu
      Abstract: We report a facile method for the adsorption separation of fluorocarbon blends containing tetrafluoroethane (R134a), pentafluoroethane (R125) and trifluoroethane (R143a) refrigerants into their pure components using commercial 13X zeolite and pore size modified 5A zeolite under ambient condition. Based on the measured R134a, R125 and R143a pure gas equilibrium adsorption isotherms, the adsorption capacity varies in the order of R134a > R143a > R125 on 13X zeolite. The mixed gas breakthrough experiments reveal that 13X zeolite selectively adsorbs R134a over R125 and R143a. By running two adsorption cycles, it is possible to obtain R134a with ultrahigh purity. Furthermore, through chemical modification of tetraethyl orthosilicate (TEOS), the pore size of 5A zeolite could be successfully narrowed to the extent to just adsorb R125 while excluding R143a. The modified 5A zeolite was utilized to separate refrigerant mixtures containing R125 and R143a into their pure components. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-02T10:41:40.716377-05:
      DOI: 10.1002/aic.15955
  • Gravitational Discharge of Fine Dry Powders with Asperities from a Conical
    • Authors: Hui Lu; Jia Zhong, Gui-Ping Cao, Hai-Feng Liu
      Abstract: The effects of particle properties, especially the surface roughness and particle type, on the gravity discharge rate and flow behavior of fine dry powders from a conical hopper are studied in detail. The van der Waals force is considered to dominate the discharge of small particles, while the empty annulus effect dominates the discharge of large particles. To predict the van der Waals force between two rough spherical particles, a model based on Rumpf theory is adopted. The effect of surface roughness can be reflected by Bond number Bog which is correlated with discharge rate. By modifying the powder bed porosity and Beverloo constant, the discharge rates of fine dry powders can be well predicted by an empirical correlation. Finally, not only the ratio of hopper outlet size to particle size D0/dp, but also the Bond number Bog is found to be an important indicator to determine the powder flowability. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:45:52.469286-05:
      DOI: 10.1002/aic.15954
  • Modeling and Prediction of Protein Solubility using the Second Osmotic
           Virial Coefficient
    • Authors: Marcel Herhut; Christoph Brandenbusch, Gabriele Sadowski
      Abstract: The development of a precipitation or crystallization step requires knowing the solubility of the target protein and its crystallization behavior in aqueous solutions at different pH, temperatures and in the presence of precipitating agents, especially salts. Within this work, a solubility model for proteins based on the second osmotic virial coefficient B22 is developed. For this, a relation between protein solubility and B22 was combined with the extended DLVO model. This solubility model was then used to model and also predict the protein solubility of lysozyme and monoclonal antibody for different salts, salt concentrations, and pH. The modeled as well predicted B22 and protein solubility data of lysozyme in the presence of sodium chloride and sodium p-toluenesulfonate and of a monoclonal antibody in the presence of ammonium sulfate at different pH shows good agreement with experimental data. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:42:19.405106-05:
      DOI: 10.1002/aic.15944
  • Chemical Solvent in Chemical Solvent: A Class of Hybrid Materials for
           Effective Capture of CO2
    • Authors: Feng-Feng Chen; Kuan Huang, Jie-Ping Fan, Duan-Jian Tao
      Abstract: Amino acid ionic liquids (AAILs) are chemical solvents with high reactivity to CO2. However, they suffer from drastic increase in viscosity upon the reaction with CO2, which significantly limits their application in the industrial capture of CO2. In this work, 1-ethyl-3-methylimidazolium acetate ([emim][Ac]) which also exhibits chemical affinity to CO2 but low viscosity, and its viscosity does not increase drastically after CO2 absorption, was proposed as the diluent for AAILs to fabricate hybrid materials. The AAIL+[emim][Ac] hybrids were found to display enhanced kinetics for CO2 absorption, and their viscosity increase after CO2 absorption are much less significant than pure AAILs. More importantly, owing to the fact that [emim][Ac] itself can absorb large amount of CO2, the AAIL+[emim][Ac] hybrids still have high absolute capacities of CO2. Such hybrid materials consisting of a chemical solvent plus another chemical solvent are believed to be a class of effective absorbents for CO2 capture. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:42:09.223407-05:
      DOI: 10.1002/aic.15952
  • Multi-scale modeling of methane catalytic partial oxidation: From the
           meso-pore to the full-scale reactor operation
    • Authors: Jorge E. P. Navalho; José M. C. Pereira, José C. F. Pereira
      Abstract: A multi-scale methodology combining three different reactor length-scales is presented to investigate the role of the catalyst internal pore structure and metal loading and dispersion on the catalyst layer and full-scale reactor performances. At the catalyst level, the methodology involves pore-scale simulations in the 3D meso- and macro-pore space. The information gathered at the catalyst level is delivered to the full-scale reactor model. The methodology is applied to a honeycomb reactor performing methane partial oxidation considering reaction kinetics described through a detailed multi-step reaction mechanism. Realistic meso- and macro-pore structures were reconstructed and combined to form specific bidisperse porous washcoat layers. The study shows that species effective diffusivities vary significantly but not in the same proportion for different structures. For structures featuring poor transport characteristics, the integral methane conversion and hydrogen selectivity are strongly affected while the reactor temperatures increase substantially. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:42:02.690345-05:
      DOI: 10.1002/aic.15945
  • Verification of Eulerian–Eulerian and Eulerian–Lagrangian simulations
           for turbulent fluid–particle flows
    • Authors: Ravi G. Patel; Bo Kong, Jesse Capecelatro, Olivier Desjardins, Rodney O. Fox
      Abstract: We present a verification study of three simulation techniques for fluid–particle flows, including an Euler–Lagrange approach (EL) inspired by Jackson's seminal work on fluidized particles, a quadrature–based moment method based on the anisotropic Gaussian closure (AG), and the traditional two-fluid model. We perform simulations of two problems: particles in frozen homogeneous isotropic turbulence (HIT) and cluster-induced turbulence (CIT). For verification, we evaluate various techniques for extracting statistics from EL and study the convergence properties of the three methods under grid refinement. The convergence is found to depend on the simulation method and on the problem, with CIT simulations posing fewer difficulties than HIT. Specifically, EL converges under refinement for both HIT and CIT, but statistics exhibit dependence on the post-processing parameters. For CIT, AG produces similar results to EL. For HIT, converging both TFM and AG poses challenges. Overall, extracting converged, parameter-independent Eulerian statistics remains a challenge for all methods. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:41:57.27573-05:0
      DOI: 10.1002/aic.15949
  • The Effect of Liquid Bridge Model Details on the Dynamics of Wet Fluidized
    • Authors: Mingqiu Wu; Johannes G. Khinast, Stefan Radl
      Abstract: Wet fluidized beds of particles in small periodic domains are simulated using the CFD-DEM approach. A liquid bridge is formed upon particle-particle collisions, which then ruptures when the particle separation exceeds a critical distance. The simulations take into account both surface tension and viscous forces due to the liquid bridge. We perform a series of simulations based on different liquid bridge formation models: (i) the static bridge model of Shi and McCarthy, (ii) a simple static version of the mode of Wu et al., as well as (iii) the full dynamic bridge model of Wu et al. We systematically compare the differences caused by different liquid bridge formation models, as well as their sensitivity to system parameters. Finally, we provide recommendations for which systems a dynamic liquid bridge model must be used, and for which application this appears to be less important. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:41:48.752007-05:
      DOI: 10.1002/aic.15947
  • Organocatalyzed Beckmann Rearrangement of Cyclohexanone Oxime in a
           Microreactor: Kinetic Model and Product Inhibition
    • Authors: Chencan Du; Jisong Zhang, Guangsheng Luo
      Abstract: This paper presents the kinetic study of Beckmann rearrangement of cyclohexanone oxime catalyzed by trifluoroacetic acid and acetonitrile in a microreactor. Parametric studies are conducted varying temperature, ratio of trifluoroacetic acid to acetonitrile, and concentration of cyclohexanone oxime. The inhibition effect of ε-caprolactam in this reaction system is firstly reported. A comprehensive mathematic kinetic model considering the product inhibition effect of caprolactam has been developed in the temperature range of 368-391 K, which agrees well with the experimental results across a broad experimental parameter space. In addition, kinetic study indicates that the esterification of cyclohexanone oxime and transposition reaction of the intermediate are both supposed to be the rate-determining steps, and in this catalyst system, the ratio of trifluoroacetic acid and acetonitrile mainly influences the reaction rate and the activation energy of the transposition step. The developed model could provide much reliable knowledge for industrial application. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:41:42.500704-05:
      DOI: 10.1002/aic.15946
  • Model of inertial spreading and imbibition of a liquid drop on a capillary
    • Authors: Michel Y. Louge; Shilpa Sahoo
      Abstract: We outline a low-order Lagrangian model for the inertial dynamics of spreading and imbibition of a spherical liquid cap on a plane featuring independent cylindrical capillaries without gravity. The analysis predicts the relative roles of radial and axial kinetic energy, reveals the critical Laplace number beyond which the drop oscillates, and attributes the exponent of the initial power-law for contact patch radius vs time to the form of capillary potential energy just after the liquid sphere touches the plate. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:41:01.40578-05:0
      DOI: 10.1002/aic.15953
  • Settling and Re-Entrainment of Wax Particles in Near-Gelling Systems
    • Authors: Seetharaman Navaneetha Kannan; Nagu Daraboina, Rama Venkatesan, Cem Sarica
      Abstract: Under near-gelling conditions, the precipitated wax particles can settle down due to gravity and form a bed at the bottom of pipeline. During the restart, the settled waxy bed can increase the pressure drop significantly, and the necessity for pigging and/or addition of chemicals has to be determined to re-entrain settled wax particles. A laboratory scale flow loop, first of its kind, has been built and used to understand the settling and re-entrainment behavior. The experimental results confirmed the settling of precipitated wax in a pipe under quiescent conditions when the oil temperature falls between Wax Appearance Temperature (WAT) and Pour Point (PP). During restart, complete re-entrainment was attained after reaching a critical flow rate. Solid transport models were able to predict reasonably good results in agreement with experiments. This work emphasizes the importance of understanding the behavior of waxy crude oil during production shut down and design appropriate startup strategies. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:35:44.786598-05:
      DOI: 10.1002/aic.15948
  • Confinement of a Polymer Chain: an Entropic Study by Monte Carlo Method
    • Authors: Flavia Ruggiero; Rosaria Aruta, Paolo Antonio Netti, Enza Torino
      Abstract: The properties of macromolecules in presence of an interface could be considerably modified due to confinement effects. When phase separations are performed in nanoconfined domains, the concurrent presence of high-energy interfaces and conformational entropy constraints of the macromolecules causes profound differences in polymer aggregation behavior. Here, thermodynamics of a polymer chain in solution, confined by a three-dimensional cubic interface, is studied by means of Monte Carlo method, focusing on the chain conformational entropy penalty arising from the excluded volume effects. The presented method might become a general tool for a preliminary evaluation of the thermodynamic effects due to the confinement of a polymer system. Further, the interface effects on Thermally Induced Phase Separation (TIPS) of polymer solutions, confined by High-Pressure Homogenization, are experimentally studied, regarding final morphologies. It is confirmed how peculiar polymer morphologies are obtained only when the TIPS develops under nanoconfinement degrees above a threshold one. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:35:40.961338-05:
      DOI: 10.1002/aic.15951
  • Nonlinear Robust Optimization for Process Design
    • Authors: Yuan Yuan; Zukui Li, Biao Huang
      Abstract: A novel robust optimization framework is proposed to address general nonlinear problems in process design. Local linearization is taken with respect to the uncertain parameters around multiple realizations of the uncertainty, and an iterative algorithm is implemented to solve the problem. Furthermore, the proposed methodology can handle different categories of problems according to the complexity of the problems. First, inequality-only optimization problem as in most existing robust optimization methods can be addressed. Second, the proposed framework can deal with problems with equality constraint associated with uncertain parameters. In the final case, we investigate problems with operation variables which can be adjusted according to the realizations of uncertainty. A local affinely adjustable decision rule is adopted for the operation variables (i.e., an affine function of the uncertain parameter). Different applications corresponding to different classes of problems are used to demonstrate the effectiveness of the proposed nonlinear robust optimization framework. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:35:34.793741-05:
      DOI: 10.1002/aic.15950
  • Sorption Enhanced Reaction for High Purity Products in Reversible
    • Authors: Fan Ni; Hugo S. Caram
      Abstract: Reversible reactions (A + B = C + D) can be carried out to near completion using an admixture of catalyst and sorbent that will selectively adsorb one of the reaction products. For an initially clean sorbent and a favorable adsorption isotherm and a long reactor, the adsorbed product, C, will propagate as a sharp, shock-like front. While the adsorbed product will not move faster than this front, the second, non-adsorbed product, D, will, in principle, leave the reactor, uncontaminated. However, a parametric analysis of the two examples presented in this work, the water gas shift and the cracking of hydrogen sulfide, reveals an unexpectedly complex behavior. While assuming adsorption equilibrium the effect of the equilibrium constant, the reaction kinetics and adsorption isotherm on the reactant and product concentration profiles are simulated. It is found that desired behavior is favored by large equilibrium constants, rapid kinetics and strong nonlinear adsorption. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-26T09:25:25.801144-05:
      DOI: 10.1002/aic.15943
  • La-hexaaluminate for Synthesis Gas Generation by Chemical Looping Partial
           Oxidation of Methane using CO2 as Sole Oxidant
    • Authors: Yanyan Zhu; Weiwei liu, Yu Kang, Xueyan Sun, Xiaodong Wang, Xiaoxun Ma, Junhu Wang
      Abstract: Chemical looping partial oxidation of methane using a sole CO2 oxidant (CL-POM-CO2) is an emerging technology for synthesis gas generation and CO2 utilization, which is highly dependent on an oxygen carrier (OC). In this work, Fe-substituted La-hexaaluminate as the OC was found to exhibit good reactivity and stability during 50 periodic CH4/CO2 redox cycles due to the formation of magnetoplumbite La-hexaaluminate structure with the introduction of La. Deeper reduction for synthesis gas generation did not destroy the La-hexaaluminate structure via a charge compensation mechanism, which increased CH4 reactivity and further improved CO2 utilization under subsequent re-oxidation. In the La-hexaaluminate structure, O6-Fe3+(Oh) was highly active for the total oxidation of methane, while O5-Fe3+(Tr) and O4-Fe3+(Th) selectively oxidized CH4 to synthesis gas. The sole CO2 oxidant only selectively recovered O5-Fe3+(Tr) and O4-Fe3+(Th), and thus is more favorable for improving synthesis gas selectivity than O2/air, which offers an attractive opportunity for CO2 utilization. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-24T11:20:34.905167-05:
      DOI: 10.1002/aic.15942
  • Automated Measurements of Gas-Liquid Mass Transfer in Micro-Packed Bed
    • Authors: Jisong Zhang; Andrew R. Teixeira, Klavs F. Jensen
      Abstract: Gas-liquid mass transfer in micro-packed bed reactors is characterized with an automated platform integrated with in-line Fourier transform infrared spectroscopy. This setup enables screening of a multidimensional parameter space underlying absorption and with chemical reaction. Volumetric gas-liquid mass transfer coefficients (kLa) are determined for the model reaction of CO2 absorption in a methyl diethanolamine/water solution. Parametric studies are conducted varying gas and liquid superficial velocities, packed bed dimensions and packing particle sizes. The results show that kLa values are in the range of 0.24∼0.64 s−1, which is about one-to-two orders of magnitude larger than those of conventional trickle beds. An empirical correlation predicts kLa in micro-packed bed reactors in good agreement with experimental data. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-24T11:20:29.607571-05:
      DOI: 10.1002/aic.15941
  • On Facilitated Computation of Mesoscopic Behavior of Reaction-Diffusion
    • Authors: Vu Tran; Doraiswami Ramkrishna
      Abstract: Various cellular and subcellular biological systems occur in the conditions where both reactions and diffusion take place. Since the concentration of species varies spatially, application of reaction-diffusion master equation (RDME) has served as an effective method to handle these complicated systems; yet solving these equation incurs a large CPU time penalty. Counter to the traditional technique of generating many sample paths, this paper introduces a method which combines Grima's effective rate equation approach1with a linear operator formalism for diffusion to capture averaged species behaviors. The formulation also shows correct results at various choices of compartment sizes, which have been found to be an important factor that can affect accuracy of the final predictions.2 It is shown that the method presented allows the computation of the mesoscopic average of reaction-diffusion systems at considerably accelerated rates (exceeding a thousand fold) over those based on sample path averages. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-24T11:20:27.542766-05:
      DOI: 10.1002/aic.15940
  • Nanoparticles@rGO Membrane Enabling Highly-enhanced Water Permeability and
           Structural Stability with Preserved Selectivity
    • Authors: Mengchen Zhang; Kecheng Guan, Jie Shen, Gongping Liu, Yiqun Fan, Wanqin Jin
      Abstract: Developing advanced membranes with high separation performance and robust mechanical properties is critical to the current water crisis. Herein, we report a general and scalable fabrication of nanoparticles (NPs)@reduced graphene oxide (rGO) membranes with significantly expanded nanochannels meanwhile ordered laminar structures using in situ synthesized NPs@rGO nanosheets as building blocks. Size- and density-controllable NPs were uniformly grown on the regularly stacked rGO nanosheets through coordination, followed by filtration-deposition on inner surface of porous ceramic tubes. The NPs bonded rGO building blocks enabled the as-prepared membranes 1-2 orders of magnitudes higher water permeance than the counterparts while keeping excellent rejections for various organic matters and ions. Moreover, the industrially preferred GO-based tubular membrane exhibited an extraordinary structural stability under high-pressure and cross-flow process of water purification, which is considered as a notable step toward realizing scalable GO-based membranes. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-24T11:20:25.109807-05:
      DOI: 10.1002/aic.15939
  • Effects of Compositional Variations on CO2 Foam under Miscible Conditions
    • Authors: S. Kahrobaei; K. Li, S. Vincent-Bonnieu, R. Farajzadeh
      Abstract: Foam can mitigate the associated problems with the gas injection by reducing the mobility of the injected gas. The presence of an immiscible oleic phase can adversely affect the foam stability. Nevertheless, under miscible conditions gas and oil mix in different proportions forming a phase with a varying composition at the proximity of the displacement front. Therefore, it is important to understand how the compositional variations of the front affect the foam behavior. In this study through several core-flood experiments under miscible condition, three different regimes were identified based on the effects of the mixed-phase composition on CO2 foam-flow behavior: In Regime 1 the apparent viscosity of the in-situ fluid was the highest and increased with increasing xCO2. In Regime 2 the apparent viscosity increased with decreasing xCO2. In Regime 3 the apparent viscosity of the fluid remained relatively low and insensitive to the value of xCO2. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-22T10:35:24.252442-05:
      DOI: 10.1002/aic.15938
  • Fenton-Like Degradation of Rhodamine B over Highly Durable Cu-Embedded
           Alumina: Kinetics and Mechanism
    • Authors: Yiyi Sheng; Yang Sun, Jing Xu, Jie Zhang, Yi-Fan Han
      Abstract: Cu-embedded mesoporous alumina, as a Fenton-like catalyst prepared via a sol-gel method, showed excellent activity and durability for the degradation of refectory compounds. The origin of active sites for the generation of hydroxyl radicals (•OH) were thoroughly studied using multi techniques. Cu, as the only active element, could be penetrated into the bulk of alumina and some Cu atoms were embedded into the framework. The dynamic structure of surface Cu species (the variety of Cu+/Cu2+ ratio) during the reaction were determined as well. Furthermore, the structure plasticity of catalyst has proved by optimizing preparation and reaction conditions. A 98.53% degradation of RhB was recorded within 30 min, following a pseudo-first-order reaction rate expression. Electron spin resonance spectra and •OH scavenging experiments have confirmed that •OH is the main reactive oxidant for the elimination of RhB. By the surface-enhanced Raman spectroscopy and gas chromatography-mass spectrometer results, plausible pathways of RhB degradation were elaborated. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-21T10:20:29.175322-05:
      DOI: 10.1002/aic.15937
  • Protic Ionic Liquid as Excellent Shuttle of MDEA for Fast Capture of CO2
    • Authors: Wen-Tao Zheng; Kuan Huang, You-Ting Wu, Xing-Bang Hu
      Abstract: A cheap protic ionic liquid (PIL), 3-(Dimethylamino)-1-propylamine acetate (abbreviated as [DMAPAH][Ac]), is investigated in this work as the activator of N-methyldiethanolamine (MDEA) for fast capture of CO2. The PIL-activated MDEA solutions show excellent performance in absorption rate and capacity (≥ 2.5 mol·kg−1). A novel absorption mechanism is proposed to account for the phenomenon, where the shuttling role of the PIL is described in detail. Additionally, the enthalpy change ΔHSOL (-45 ∼ -52 kJ·mol−1), the turnover number of the PIL and the regeneration efficiency (> 92%) are also measured. All these data show that the PIL-mediated MDEA solutions may be used as a kind of promising absorbents for fast capture of CO2. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-21T04:59:21.175095-05:
      DOI: 10.1002/aic.15921
  • On the use of a powder rheometer to characterize the powder flowability at
           low consolidation with torque resistances
    • Authors: Hamid Salehi; Denis Schütz, Richard Romirer, Diego Barletta, Massimo Poletto
      Abstract: The Anton Paar Powder Cell was used to measure the torque necessary to rotate an impeller in beds of glass beads, sand and alumina powders aerated between no aeration to the minimum for fluidization. Measured torque values depend on the material tested, on the air flow rate applied, on the impeller depth and on the height of the impeller blade. The effect of the impeller depth is linear for low impeller depth and is less than linear at high depth values. A model was developed for the interpretation of the experimental results based on the idea that the material is shearing on the surface described by the impeller rotation. The model allows to estimate an effectiveness of the impeller in the torque determination and also to predict the torque for the impeller at the at deepest positions at which the wall effects have to be considered. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-17T10:45:45.750695-05:
      DOI: 10.1002/aic.15934
  • Experiments on Breakup of Bubbles in a Turbulent Flow
    • Authors: Jiří Vejražka; Mária Zedníková, Petr Stanovský
      Abstract: The breakup of air bubbles in a turbulent water flow is studied experimentally. Water flows from a nozzle array, generating intense turbulence, and then flows downward through a cell. The velocity field is measured by PIV, and the local dissipation rate is estimated using a large-eddy PIV technique. Bubbles (1.8 to 5 mm) are injected in the bottom of the cell and rise toward the region of intense turbulence, where they break. The time spent by bubbles in various zones without breaking and the number of breakups are evaluated, providing information about the breakup frequency. The number of daughter bubbles and their size distribution are determined. The number of daughters depends on a Weber number 2ρε2/3 D'5/3/σ, where ε is the turbulent energy dissipation rate, D' is the mother particle size, ρ and σ are the liquid density and surface tension. The daughter size distribution is a function of their number. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-17T10:45:43.520383-05:
      DOI: 10.1002/aic.15935
  • Ultrasound–Assisted Synthesis and Characterization of Polymethyl
           Methacrylate/Reduced Graphene Oxide Nanocomposites
    • Authors: Maneesh Kumar Poddar; Mohammad Arjamand, Uttandaraman Sundararaj, Sushobhan Pradhan, Vijayanand S. Moholkar
      Abstract: This paper reports ultrasound–assisted synthesis of polymethyl methacrylate (PMMA)/reduced graphene oxide (RGO) nanocomposites by in–situ emulsion polymerization coupled with in–situ reduction of graphene oxide. The thermal degradation kinetics of the nanocomposites was also assessed with Criado and Coats-Redfern methods. Intense micro-convection generated by ultrasound and cavitation results in uniform dispersion of RGO in the polymer matrix, which imparts markedly higher physical properties to resulting nanocomposites at low (≤ 1.0 wt%) RGO loadings, as compared to nanocomposites synthesized with mechanical stirring. Some important properties of the PMMA/RGO nanocomposites synthesized with sonication (with various RGO loadings) are: glass transition temperature (0.4 wt%) = 124.5°C, tensile strength (0.4 wt%) = 40.4 MPa, electrical conductivity (1.0 wt%) = 2 × 10−7 S/cm, electromagnetic interference shielding effectiveness (1.0 wt%) = 3.3 dB. Predominant thermal degradation mechanism of nanocomposites (1.0 wt% RGO) is 1-D diffusion with activation energy of 111.3 kJ/mol. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-17T10:45:30.613722-05:
      DOI: 10.1002/aic.15936
  • Gas Drying with Ionic Liquids
    • Authors: Jingli Han; Chengna Dai, Lei Zhigang, Biaohua Chen
      Abstract: The gas drying technology with ionic liquids (ILs) was systematically studied ranging from the molecular level to industrial scale. The COSMO-RS model was first used to screen the suitable IL and provide theoretical insights at the molecular level. Towards CO2 gas dehydration, we measured the CO2 solubility in single [EMIM][Tf2N] and in the [EMIM][Tf2N] + H2O mixture, as well as the vapor-liquid equilibrium (VLE) of [EMIM][Tf2N] + H2O system, to justify the applicability of UNIFAC model. Based on the thermodynamic study, the rigorous equilibrium (EQ) stage mathematical model was established for process simulation. The gas drying experiment with IL was also carried out, and the water content in gas product can be reduced to 375 ppm. It was confirmed that a less flow rate of absorbent, a higher CO2 recovery ratio and a much lower energy consumption can be achieved with IL than with the conventional triethylene glycol (TEG). This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T11:06:00.956979-05:
      DOI: 10.1002/aic.15926
  • Chaotic Mixing in a Barrier-Embedded Partitioned Pipe Mixer
    • Authors: Seon Yeop Jung; Kyung Hyun Ahn, Tae Gon Kang, Gi Taek Park, Sang Ug Kim
      Abstract: Inspired by the partitioned-pipe mixer (PPM), a barrier-embedded partitioned pipe mixer (BPPM) is designed and analyzed using a numerical simulation scheme. The BPPM is a static mixer, composed of orthogonally connected rectangular plates with a pair of barriers, which divide, stretch, and fold fluid elements, leading to chaotic mixing via the baker's transformation. The aspect ratio of the plate (α) and the dimensionless height of the barrier (β) are chosen as design parameters to conduct a parameter study on the mixing performance. The flow characteristics and mixing performance are analyzed using the cross-sectional velocity vectors, Poincaré section, interface tracking, and the intensity of segregation. The results indicate that several designs of the BPPM significantly enhance the PPM's mixing performance. The best BPPMs are identified with regard to compactness and energy consumption. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T11:05:57.928475-05:
      DOI: 10.1002/aic.15929
  • CFD Simulation of the Effect of Rain on the Performance of Horizontal Wind
    • Authors: Hamid Arastoopour; Aiden Cohan
      Abstract: Wind turbine power output is influenced by environmental conditions, including rain. Therefore, a better understanding of the effect of rain on the performance of wind turbines is necessary. Our coupled Lagrangian-Eulerian multiphase computational fluid dynamics model was modified to more accurately simulate the momentum transfer during water film formation on the airfoils of a horizontal-axis turbine and the performance loss caused by the rainwater film on the National Renewable Energy Laboratory (NREL) turbine performance. To obtain three-dimensional numerical simulation of the wind turbine in manageable computational time, we made simplifying assumptions and verified the validity of these assumptions by simulating the flow over the S809 airfoil of the NREL turbine. In a dry environment, simulation of turbine power output agreed well with NREL experimental data. Our multiphase model showed that the rain film accumulation and flow on the surface of the turbine airfoil reduces the power output of the turbine. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T11:05:29.911494-05:
      DOI: 10.1002/aic.15928
  • Using the Discrete Element Method to develop Collisional Dissipation Rate
           Models that Incorporate Particle Shape
    • Authors: Kevin E. Buettner; Yu Guo, Jennifer S. Curtis
      Abstract: Discrete Element Method (DEM) simulations of Homogeneous Cooling Systems (HCS) are used to develop a collisional dissipation rate model for non-spherical particle systems that can be incorporated in a two-fluid multiphase flow framework. Two types of frictionless, elongated particle models are compared in the HCS simulations: glued-sphere and true cylinder. Simulation results show that the ratio of translational to rotational granular temperatures is equal to one for the true cylindrical particles with particle aspect ratios (AR) greater than one and glued-sphere particles with AR > 1.5, while the temperature ratio is less than one for glued-sphere particles with 1 
      PubDate: 2017-08-14T11:05:24.559378-05:
      DOI: 10.1002/aic.15933
  • Plasma Assisted Nitrogen Oxide Production from Air: Using Pulsed Powered
           Gliding Arc Reactor for a Containerized Plant
    • Authors: B. S. Patil; F. J. J. Peeters, J. A. Medrano, G. J. van Rooij, F. Gallucci, J. Lang, Q. Wang, V. Hessel
      Abstract: The production of NOx from air and air+O2 is investigated in a pulsed powered milli-scale gliding arc (GA) reactor, aiming at a containerized process for fertilizer production. Influence of feed mixture, flowrate, temperature, and Ar and O2 content are investigated at varying specific energy input. The findings are correlated with high-speed imaging of the GA dynamics. An O2 content of 40-48% was optimum, with an enhancement of 11% in NOx production. Addition of Ar and preheating of the feed resulted in lower NOx production. Lower flowrates produced higher NO concentrations due to longer residence time in the GA. The volume covered by GA depends strongly on the gas flowrate, emphasizing that the gas flowrate has a major impact on the GA dynamics and the reaction kinetics. For 0.5 L/min, 1.4 vol% of NOx concentration was realized, which is promising for a containerized process plant to produce fertilizer in remote locations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T11:01:37.642803-05:
      DOI: 10.1002/aic.15922
  • Quantitative and Qualitative Studies of Microorganisms involved in
           Full-scale Autotrophic Nitrogen Removal Performance
    • Authors: Barbara Muñoz-Palazon; Alejandro Rodriguez-Sanchez, Antonio Castellano-Hinojosa, Jesus Gonzalez-Lopez, Mark C.M. van Loosdrecth, Riku Vahala, Alejandro Gonzalez-Martinez
      Abstract: Autotrophic nitrogen removal systems have been implemented at full-scale and provide an efficient way for nitrogen removal from industrial and urban wastewaters. Our study present qualitative and quantitative analysis of archaeal and bacterial amoA genes and Candidatus Brocadiales bacteria analyzed in six full-scale autotrophic nitrogen removal bioreactors. The results showed that Ammonium Oxidizing Bacteria (AOB) were detected in all bioreactors. However, Ammonium Oxidizing Archaea (AOA) were detected only in the non-aerated technologies. On the other hand, different Candidatus Brocadiales phylotypes appeared due to differences in influent wastewater composition and hydraulic retention time (HRT). In the same terms multivariate redundancy analysis confirmed that AOA was positively correlated with temperature, ammonium concentration and low HRT. However, AOB population was positively correlated with pH, temperature and dissolved oxygen concentration. Our data suggested a correlation between the microorganisms involved in the nitrogen removal performance and the operational conditions in the different full-scale bioreactors. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T11:00:37.857253-05:
      DOI: 10.1002/aic.15925
  • Model for the Outer Cavity of a Dual-Cavity Die with Parameters Determined
           by Two-Dimensional Finite-Element Analysis
    • Authors: Kenneth J. Ruschak; Steven J. Weinstein
      Abstract: A coating die forms liquid layers of uniform thickness for application to a substrate. In a dual-cavity coating die an outer cavity and slot improves flow distribution from an inner cavity and slot. A model for axial flow in the outer cavity must consider the ever present cross flow. A one-dimensional equation for the pressure gradient for a power-law liquid is obtained as a small departure from a uniform flow distribution and no axial flow. The equation contains a shape factor dependent on cavity shape, Reynolds number, and power-law index. The shape factor for five triangular cavity shapes is obtained by finite-element analysis and correlated for application to die design up to the onset of flow recirculation which arises at the junction of the cavity and outer slot. The performance of the combined cavity and slot is considered and the most effective design determined. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T11:00:33.45287-05:0
      DOI: 10.1002/aic.15927
  • Particle-Resolved PIV Experiments of Solid-Liquid Mixing in a Turbulent
           Stirred Tank
    • Authors: Genghong Li; Zhengming Gao, Zhipeng Li, Jiawei Wang, J.J. Derksen
      Abstract: Particle Image Velocimetry (PIV) experiments on turbulent solid-liquid stirred tank flow with careful refractive index matching of the two phases have been performed. The spatial resolution of the PIV data is finer than the size of the spherical, uniformly sized solid particles, thereby providing insight in the flow around individual particles. The impeller is a down-pumping pitch-blade turbine. The impeller-based Reynolds number has been fixed to Re=104. Overall solids volume fractions up to 8% have been investigated. The PIV experiments are impeller-angle resolved, i.e. conditioned on the angular position of the impeller. The two-phase systems are in partially suspended states with an inhomogeneous distribution of solids: high solids loadings near the bottom and near the outer walls of the tank, much less solids in the bulk of the tank. The liquid velocity fields show very strong phase coupling effects with the particles increasingly attenuating the overall circulation patterns as well as the liquid velocity fluctuation levels when the solids volume fraction is increased. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T11:00:30.294146-05:
      DOI: 10.1002/aic.15924
  • Dynamic Formation and Scaling Law of Hollow Droplet with Gas/Oil/Water
           System in Dual-Coaxial Microfluidic Devices
    • Authors: Fu-Ning Sang; Zhuo Chen, Yun-Dong Wang, Jian-Hong Xu
      Abstract: Based on the one-step microfluidic method of producing hollow droplet with thin film, this article studies the effect of water and oil flow rate, gas pressure and viscosity of aqueous phase on the dynamic formation and size of hollow droplet by analyzing large amounts of data acquired automatically. The results show that the filling stage of hollow droplet is similar to that of microbubble formation, while the necking stage is similar to that of droplet formation process. Furthermore, based on the data and mathematical model describing droplet formation mechanism, a filling stage model including Capillary number of continuous phase is developed. Considering the dynamic interface breakup and displacement of droplet in necking stage, a necking stage model is developed. The results show that the model results considering filling and necking stage fit well with the experimental data, and the relative error is less than 5%. Finally, the same model with parameters is used to predict the size of hollow droplet with other systems and devices, and the model is proved to be relative precise in our experimental conditions. The results presented in this work provide a more in-depth understanding of the dynamic formation and scaling law of hollow droplet with G/L/L systems in microfluidic devices. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T11:00:23.947198-05:
      DOI: 10.1002/aic.15930
  • Kinetics of Glycerol Conversion to Hydrocarbon Fuels over Pd/H-ZSM-5
    • Authors: Yang Xiao; Arvind Varma
      Abstract: The utilization of glycerol, primary byproduct of biodiesel production, is important to enhance process economics. In our recent prior work, it was shown that glycerol can be converted to hydrocarbon fuels over bifunctional catalysts, containing a noble metal supported on H-ZSM-5. Over Pd/H-ZSM-5 catalyst, an optimal ∼60% yield of hydrocarbon fuels was obtained. In the present work, based on experimental data over Pd/H-ZSM-5 catalyst, a lumped reaction network and kinetic model are developed. Using differential kinetic experiments over the temperature range 300-450°C, the rate constants, reaction orders and activation energies are obtained for each reaction step. The predicted values match well with experimental data for glycerol conversion up to ∼90%. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T11:00:19.259015-05:
      DOI: 10.1002/aic.15931
  • Interface-Shrinkage-driven Breakup of Droplets in Micro-devices with
           different Dispersed Fluid Channel Shape
    • Authors: Wenjie Lan; Zhihui Wang, Yinjie Du, Xuqiang Guo, Shaowei Li
      Abstract: We previously proposed a new droplet breakup mechanism — interface-shrinkage-driven breakup. In co-axial microdevices, when the contact angle between the continuous phase and dispersed fluid channel is sufficiently low, the new mechanism instead of the classic shear-driven mechanism dominates the breakup. The present study further investigated the new mechanism in microdevices with dispersed fluid channels of different shape. Critical contact angles in different devices were determined by theoretical analysis and verified by experiments. It was found that the critical contact angle for the new mechanism depends on the shape of the dispersed fluid channel. The droplet size was measured for different devices when the new mechanism dominated the breakup. In contrast to the case for the shear-driven mechanism, the droplet size is little affected by the capillary number. Mathematical models were established to predict the droplet size in different devices and results were found to agree well with experimental results. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T10:55:31.273356-05:
      DOI: 10.1002/aic.15932
  • Bubble Splitting under Gas-Liquid-Liquid Three-Phase Flow in a Double
           T-junction Microchannel
    • Authors: Yanyan Liu; Jun Yue, Shuainan Zhao, Chaoqun Yao, Guangwen Chen
      Abstract: Gas-aqueous liquid-oil three-phase flow was generated in a microchannel with a double T-junction. Under the squeezing of the dispersed aqueous phase at the second T-junction (T2), the splitting of bubbles generated from the first T-junction (T1) was investigated. During the bubble splitting process, the upstream gas-oil two-phase flow and the aqueous phase flow at T2 fluctuate in opposite phases, resulting in either independent or synchronous relationship between the instantaneous downstream and upstream bubble velocities depending on the operating conditions. Compared with two-phase flow, the modified capillary number and the ratio of the upstream velocity to the aqueous phase velocity were introduced to predict the bubble breakup time. The critical bubble breakup length and size laws of daughter bubbles/slugs were thereby proposed. These results provide an important guideline for designing microchannel structures for a precise manipulation of gas-liquid-liquid three-phase flow which finds potential applications among others in chemical synthesis. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T10:55:28.484738-05:
      DOI: 10.1002/aic.15920
  • Adiabatic Time to Maximum Rate Evaluation using an Analytical Approach
    • Authors: Roberto Sanchirico
      Abstract: This article presents an analytical method for the calculation of the adiabatic time to maximum rate. The procedure is developed considering a thermal decomposition process described by a simple n-order kinetic and is based on the introduction of a special function that is possible by integrating analytically. The application of the method requires the knowledge of the thermokinetic parameters of the process under study and allows the calculation of the adiabatic time to maximum rate without the numerical integration of the heat and mass balance equations or the use of relationships based on particular simplifying hypotheses. Its validity has been demonstrated considering numerical and real experiments (thermal decomposition of trityl azide) providing in both cases times to maximum rate values which are very close to the real ones. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T10:55:26.272667-05:
      DOI: 10.1002/aic.15923
  • Economic Assessment of Carbon Capture by Minichannel Absorbers
    • Authors: Ziqiang Yang; Tariq S. Khan, Mohamed Alshehhi, Yasser F. AlWahedi
      Abstract: In this work we present a physio-economic model supported by lab scale experiments assessing the economic viability of minichannel based carbon capture units. The Net Present Value of capital and operating Costs (NPVC) ensued throughout the plant life is selected as the benchmarking parameter. An optimization problem is formulated and solved with the objective of minimizing the NPVC of the unit subject to constraints imposed by the physics of absorption and pressure drop limits; both of which are captured via experimentally deduced empirical correlations. The results show that the minichannel absorbers are economically competitive to conventional systems for low capacity CO2 capture achieving savings ranging from ∼50% to 3% for plant capacities ranging from 5 to 50 MMSCFD respectively primarily due to their lower capital costs. At higher plant capacities, the higher operating costs of the minichannel units dominate their NPVC and as such lead them to lose their competitiveness. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-14T10:55:24.026502-05:
      DOI: 10.1002/aic.15919
  • Kinetic and Transport Effects on Enzymatic Biocatalysis Resulting from the
           PEGylation of Cofactors
    • Authors: Harun F. Ozbakir; Scott Banta
      Abstract: The utilization of cofactor-dependent redox enzymes in bioprocess technologies requires low cost cofactor regeneration methods. PEGylated NAD(H) (PEG-NAD(H)) has been utilized in enzyme membrane reactors as a means to recover the cofactor; however, there is a lack of understanding of the effect of PEGylation on enzymatic activity, especially on the relationship between biocatalysis and transport phenomena. To explore this further, two redox enzymes (formate dehydrogenase (FDH) from S. cerevisiae and NAD(H)-dependent D-lactate dehydrogenase (nLDH) from E.coli) have been chosen and the kinetic effects caused by cofactor modifications (with PEG of three different chain lengths) have been investigated. The PEGylation did not impact the cofactor dissociation constants and mass transfer was not the rate-limiting step in biocatalysis for either enzyme. However, the PEG chain length had different impacts on the formation of enzyme/cofactor and/or enzyme/cofactor/substrate ternary complexes for the enzymes. This article is protected by copyright. All rights reserved.
      PubDate: 2017-08-09T03:05:22.150096-05:
      DOI: 10.1002/aic.15893
  • Systematic Analysis and Optimization of Power Generation in Pressure
           Retarded Osmosis: Effect of Multi-Stage Design
    • Authors: Mingheng Li
      Abstract: This work presents a systematic method for analysis and optimization of specific energy production (SEP) of PRO systems employing single-stage configuration as well as multi-stage design with inter-stage hydro-turbines. It is shown that the SEP nor- malized by the draw solution feed osmotic pressure increases with the number of stages as well as a dimensionless parameter γtot = AtotLpπ0 = Q0. As compared to the single- stage PRO, the multi-stage arrangement not only increases ux and volume gain, but also allows a stage-dependent, progressively decreasing hydraulic pressure, both of which contribute to enhanced SEP and power density. At the thermodynamic limit where tot goes to infinity, the theoretical maximum SEP by an N-stage PRO system is N *******, where qtot is the ratio of the draw solution ow rate at the outlet to the inlet on the system level. For single-stage PRO, it is no more than π0. For infinite number of stages, the theoretical limit becomes (ln qtot)π0. SEP under realistic conditions and practical constraints on multi-stage design are discussed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-31T11:10:28.525393-05:
      DOI: 10.1002/aic.15894
  • Intrusive Probes in Riser Applications
    • Authors: Ray A. Cocco; S.B. Reddy Karri, Ted M. Knowlton, John Findlay, Thierry Gauthier, Jia Wei Chew, Christine M. Hrenya
      Abstract: Many of the probes used to understand hydrodynamics in circulating fluidized bed risers intrude into the environment they are measuring, although assumptions are typically asserted that the intrusive probes do not affect the data collected. This could be a poor assumption in some cases and conditions. We found that intrusive fiber optic probe measurements consistently mis-predicted the solids concentration compared to the non-intrusive pressure drop measurements outside the fully developed flow region of a riser containing fluid catalytic cracking catalyst or glass bead particles. The discrepancy was sensitive to superficial gas velocity, solid circulation rate, probe position and flow direction. Barracuda VR™ computational fluid dynamics simulations confirmed this, and indicated that particle momentum was lost at the leading edge of the probe and particles were spilling over to the probe tip. Accordingly, new probe designs were proposed to mitigate the intrusiveness of a fiber optical probe for more accurate characterization. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-28T06:45:42.075365-05:
      DOI: 10.1002/aic.15892
  • Tensile Modulus of Polymer/CNT Nanocomposites containing Networked and
           dispersed Nanoparticles
    • Authors: Yasser Zare; Kyong Yop Rhee
      Abstract: The properties of three-dimensional networks of nanoparticles in polymer/CNT nanocomposites (PCNT) are particularly interesting from fundamental and application views. In this paper, a new model is suggested for predicting the tensile modulus of PCNT using the Ouali and Paul models. The Ouali model considers the network of CNT in a polymer matrix, while the Paul model predicts the tensile modulus of samples containing dispersed nanoparticles. The predictions of the suggested approach are compared with experimental data from several samples. Also, the roles of the main parameters in the tensile modulus of PCNT are evaluated. The predictions agree with the experimental results at different filler concentrations. The roles of these parameters on the tensile modulus of PCNT are discussed based on the properties of CNT networks. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-28T06:45:26.170362-05:
      DOI: 10.1002/aic.15891
  • Steady Microfluidic Measurements of Mutual Diffusion Coefficients of
           Liquid Binary Mixtures
    • Authors: Anne Bouchaudy; Charles Loussert, Jean-Baptiste Salmon
      Abstract: We present a microfluidic method leading to accurate measurements of the mutual diffusion coefficient of a liquid binary mixture over the whole solute concentration range in a single experiment. This method fully exploits solvent pervaporation through a poly(dimethylsiloxane) (PDMS) membrane to obtain a steady concentration gradient within a microfluidic channel. Our method is applicable for solutes which cannot permeate through PDMS, and requires the activity and the density over the full concentration range as input parameters. We demonstrate the accuracy of our methodology by measuring the mutual diffusion coefficient of the water (1) + glycerol (2) mixture, from measurements of the concentration gradient using Raman confocal spectroscopy and the pervaporation-induced flow using particle tracking velocimetry. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-27T10:20:27.247365-05:
      DOI: 10.1002/aic.15890
  • Formation of Liquid-Liquid Slug Flow in a Microfluidic T-junction: Effects
           of Fluid Properties and Leakage Flow
    • Authors: Chaoqun Yao; Yanyan Liu, Chao Xu, Shuainan Zhao, Guangwen Chen
      Abstract: Characteristics of liquid-liquid slug flow are investigated in a microchannel with focus on the leakage flow that bypasses droplets through channel gutters. The results show that the leakage flow rate varies in a range of 10.7 ∼ 53.5% and 8.3 ∼ 30.9% of the feed flow rate, during the droplet formation (i.e., at T-junction) and downstream flow (i.e., in the main channel), respectively, which highly depends on Ca number and wetting condition. Empirical correlations are proposed to predict them for perfectly and partially wetting conditions. Leakage flow contribution is further used to improve the Garstecki model for size scaling in order to extend its suitability for both squeezing and shearing regimes. The instantaneous flow rates of the immiscible phases are found to fluctuate periodically with the formation cycles, but in opposite behavior. The effect of the presence of leakage flow on such fluctuation are investigated and compared with gas-liquid systems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-26T10:10:26.141307-05:
      DOI: 10.1002/aic.15889
  • Complete Carbon Analysis of Sulfur-Containing Mixtures using Post-Column
           Reaction and Flame Ionization Detection
    • Authors: Connor A. Beach; Kristeen E. Joseph, Charles S. Spanjers, Andrew J. Jones, Triantafillos J. Mountziaris, Paul J. Dauenhauer
      Abstract: Quantitative analysis of complex mixtures containing hundreds-to-thousands of organic compounds rich in heteroatoms, including oxygen, sulfur, and nitrogen, is a major challenge in the fuel, food, and chemical industries. In this work, a two-stage (oxidation and methanation) catalytic process in a 3D-printed metal microreactor was evaluated for its capability to convert sulfur-containing organic compounds to methane. The microreactor was inserted into a gas chromatograph between the capillary column and flame ionization detector. Catalytic conversion of all sulfur-containing analytes to methane enabled carbon quantification without calibration, by the method identified as “quantitative carbon detection” or QCD. Quantification of tetrahydrothiophene, dimethyl sulfoxide, diethyl sulfide, and thiophene indicated complete conversion to methane at 450°C. Long-term performance of a commercial microreactor was evaluated for 2,000 consecutive injections of sulfur-containing organic analytes. The sulfur processing capacity of the microreactor was identified experimentally, after which reduced conversion to methane was observed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-26T10:05:23.015485-05:
      DOI: 10.1002/aic.15888
  • Kinetic Monte Carlo Simulation for Homogeneous Nucleation of Metal
           Nanoparticles during Vapor Phase Synthesis
    • Authors: Seyyed Ali Davari; Dibyendu Mukherjee
      Abstract: We present a free-energy driven kinetic Monte Carlo model to simulate homogeneous nucleation of metal nanoparticles (NPs) from vapor phase. The model accounts for monomer-cluster condensations, cluster-cluster collisions, and cluster evaporations simultaneously. Specifically, we investigate the homogeneous nucleation of Al NPs starting with different initial background temperatures. Our results indicate good agreement with earlier phenomenological studies using the Gibbs' free energy formulation from Classical Nucleation Theory (CNT). Furthermore, nucleation rates for various clusters are calculated through direct cluster observations. The steady state nucleation rate estimated using two different approaches namely, the Yasuoka-Matsumoto (YM) and mean first passage time (MFPT) methods indicate excellent agreement with each. Finally, our simulation results depict the expected increase in the entropy of mixing as clusters approach the nucleation barrier, followed by its subsequent drastic loss after the critical cluster formation resulting from first-order phase transitions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-24T17:06:12.989891-05:
      DOI: 10.1002/aic.15887
  • Influence and CFD Analysis of Cooling Air Velocity on the Purification of
           Aqueous Nickel Sulfate Solutions by Freezing
    • Authors: M. Hasan; Roman Filimonov, Miia John, Joonas Sorvari, M. Louhi-Kultanen
      Abstract: Finite energy resources and their rapidly waning imprint necessitate a sustainable wastewater treatment method. Nature could be exploited to freeze wastewater in locations which experience subzero temperatures during winter. The two most vital components that influence the efficiency of natural freezing are the ambient temperature and air velocity. The turbulent and unsteady air-cooled natural freezing is simulated for ice crystallization from 0.1 wt-% and 1 wt-% NiSO4 (aq) solutions. The efficiency of natural freezing is tested for different air velocities (2 ms−1, 5 ms−1) and levels of undercooling (ΔT=0.5˚C, 1˚C) from the freezing temperature of the corresponding solution. The airflow in the winter simulator is modeled by computational fluid dynamics (CFD) to investigate its behavior and to assess its effect on freezing. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-22T11:05:38.368865-05:
      DOI: 10.1002/aic.15885
  • Molecular Simulation Study of Aluminum – Noble Gas Interfacial Thermal
           Accommodation Coefficients
    • Authors: Haoyan Sha; Gulcin Tetiker, Peter Woytowitz, Roland Faller
      Abstract: Thermal accommodation coefficients (TAC) between aluminum and noble gases were studied with molecular dynamics (MD) simulations. Gases interacting with aluminum substrates were modeled by MD with gas velocities sampled from the Maxwell – Boltzmann distribution to give accumulated TAC results. Different implementations of the equation to calculate the TAC, which differ in the amount of information gleaned from MD and the corresponding simulation results, were carefully discussed. The best formula for molecular dynamics modeling in finite simulation time was determined. Additionally, the influence of the combining rules applied on aluminum – noble gas interatomic potential was characterized with the well-known Lennard – Jones 12 – 6 potential combined with Lorentz – Berthelot and Fender – Halsey mixing rules. The results were compared with experimental values and previous analytical model. TACs simulated with Fender – Halsey rules present excellent agreement with the experimental values. Detailed TAC distributions and accumulated TAC convergence are also included. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-22T11:05:32.622228-05:
      DOI: 10.1002/aic.15886
  • Considerations on film reactivity in the aqueous biphasic hydroformylation
    • Authors: H. Warmeling; A.-C. Schneider, A. J. Vorholt
      Abstract: In experiments and kinetic models it was shown that the reaction rate of the biphasic aqueous hydroformylation of 1-octene is linear dependent on the created interfacial area. This phenomenon is directly linked to the question whether the reaction takes place in the bulk phase and is mass transfer limitation or at the surface which would mean an increase of reaction space. To evaluate the place of reaction a mass transfer analysis has been carried out. No mass transfer limitation for the gaseous components carbon monoxide and hydrogen as well as the olefin 1-octene was determined for the aqueous catalyst phase by calculating the Hatta numbers. With this observation it is possible to exclude the mass transfer as a potential influence and hence the aqueous bulk as the place of reaction. Thus the reaction is most probably surface active. This can be either explained the increase in film volume fraction where non-polar substrate as well as polar catalyst complex is present or through an increased catalyst concentration at the surface through dipole moment fluctuations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-22T11:00:24.330841-05:
      DOI: 10.1002/aic.15884
  • A Comprehensive Analysis of the BET Area for Nanoporous Materials
    • Authors: Yun Tian; Jianzhong Wu
      Abstract: The Brunauer-Emmett-Teller (BET) method has been used extensively to characterize the surface areas of porous materials by semi-empirical fitting of gas-adsorption isotherms. However, questions arise recently concerning the applicability and the exact meaning of the BET areas. In particular, there has been much debate about whether the BET method provides a faithful description of the geometrical areas of porous materials if the atomic structures are exactly known. In this work, we provide a comprehensive analysis of the BET areas for both model slit pores and crystalline porous materials using the grand canonical Monte Carlo simulation. Based on extensive simulation data for nitrogen adsorption at 77 K and the conventional models of materials characterization, we find no simple correlation between the BET and geometrical surface areas. For materials with the same BET area, their geometric surface areas may vary over one order of magnitude. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-21T11:16:04.000004-05:
      DOI: 10.1002/aic.15880
  • A Semi-analytical Model for Simulating Real Gas Transport in Nanopores and
           Complex Fractures of Shale Gas Reservoirs
    • Authors: Weihong Wang; Wei Yu, Xiaohu Hu, Hua Liu, Youguang Chen, Kan Wu, Biyi Wu
      Abstract: An efficient gridless semi-analytical model was developed to simulate real gas transport in shale formation with nanopores and complex fracture geometry. This model incorporates multiple physics such as gas desorption, adsorbed gas porosity, gas slippage and diffusion, residual water saturation, non-Darcy flow, choke skin, and pressure-dependent matrix permeability and fracture conductivity. Additionally, this model is easy to handle complex fracture geometry through dividing fractures into a number of segments and nodes. We verified the model against a numerical model and an analytical model for bi-wing hydraulic fractures. After validation, the impacts of all these physics on well performance were evaluated in detail through a series of case studies. The simulation results confirm that modeling of gas production from complex fracture geometry as well as modeling important physics in shale gas reservoirs is significant. This study improves our understanding of critical physics affecting gas recovery in shale gas reservoirs. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-21T11:16:01.831887-05:
      DOI: 10.1002/aic.15881
  • A New Superstructure Optimization Paradigm for Process Synthesis with
           Product Distribution Optimization: Application to An Integrated Shale Gas
           Processing and Chemical Manufacturing Process
    • Authors: Jian Gong; Fengqi You
      Abstract: We propose a novel process synthesis framework that combines product distribution optimization of chemical reactions and superstructure optimization of the process flowsheet. A superstructure with a set of technology/process alternatives is first developed. Next, the product distributions of the involved chemical reactions are optimized to maximize the profits of the effluent products. Extensive process simulations are then performed to collect high-fidelity process data tailored to the optimal product distributions. Based on the simulation results, a superstructure optimization model is formulated as a mixed-integer nonlinear program (MINLP) to determine the optimal process design. A tailored global optimization algorithm is employed to efficiently solve the large-scale nonconvex MINLP problem. The resulting optimal process design is further validated by a whole-process simulation. The proposed framework is applied to a comprehensive superstructure of an integrated shale gas processing and chemical manufacturing process, which involves steam cracking of ethane, propane, n-butane, and i-butane. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-21T11:15:45.027113-05:
      DOI: 10.1002/aic.15882
  • CFD as an approach to understand flammable dust 20 L standard test: effect
           of the ignition time on the fluid flow
    • Authors: Daniel Vizcaya; Carlos Murillo, Andrés Pinilla, Mariangel Amín, Nicolás Ratkovich, Felipe Munoz, Nathalie Bardin-Monnier, Olivier Dufaud
      Abstract: A computational study based on the Euler-Lagrange approach was developed for the characterization of flammable dusts in the 20 L sphere standard test. The aim of the study was to analyze some parameters that might affect the experimental data (e.g. cold turbulence and particle size). The turbulence of a wheat starch cloud was described with the Detached Eddy Simulation model. Both the pressure of the system and the RMS velocity were compared with the flow patterns established with a particle image velocimetry analysis. It was concluded that the rebound nozzle forms a cloud that is composed by clumps. This fact implies dissimilarities between the local concentrations and the nominal value. Finally, a granulometric analysis established that the mean diameter of the particle size distribution (PSD) decreased by 69% during the dispersion. Thus, it is suggested to consider the PSD at the ignition zone rather than the PSD of the sample. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-21T11:15:26.161092-05:
      DOI: 10.1002/aic.15883
  • Investigation of Gas-Solid Bubbling Fluidized Beds using ECT with a
           Modified Tikhonov Regularization Technique
    • Authors: Qiang Guo; Shuanghe Meng, Dehu Wang, Yinfeng Zhao, Mao Ye, Wuqiang Yang, Zhongmin Liu
      Abstract: Electrical Capacitance Tomography (ECT) provides a non-intrusive means to visualize cross-sectional material distribution of gas-solid bubbling fluidized beds. Successful application of ECT strongly depends on the image reconstruction algorithm used. For on-line measurements of bubbling fluidized beds, employing an algorithm that can produce high-quality images without extensive computation is necessary. Using the conventional Tikhonov regularization algorithm, image quality in the central area is basically satisfied but suffers from artifacts in the near-wall region. To solve this problem, a similar division operation learned from linear back projection was introduced to modify the conventional Tikhonov algorithm. Both numerical simulations and experiments were performed to evaluate the modified technique. The results indicate that the artifacts can be effectively removed and the reconstructed image quality is similar to Landweber method with dozens of iterations. Furthermore, the modified Tikhonov technique shows high accuracy when obtaining important hydrodynamic parameters in gas-solid bubbling fluidized beds. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-20T10:25:45.362589-05:
      DOI: 10.1002/aic.15879
  • Development of a COSMO-RS based model for the calculation of phase
           equilibria in electrolyte systems
    • Authors: Thomas Gerlach; Simon Müller, Irina Smirnova
      Abstract: A new electrolyte model, which is based on the predictive thermodynamic model COSMO-RS, is presented. For this purpose, an implementation of COSMO-RS that allows the integration of multiple segment descriptors was developed. To aid in the development of the electrolyte model, a new technique is presented that allows the evaluation of the different contributions of the interaction terms of COSMO-RS to the partial molar enthalpies. General empirical interaction energy equations are introduced into the electrolyte model. They are parameterized based on a large training set of mean ionic activity coefficients as well as liquid-liquid equilibrium data close to ambient conditions. The model is shown to be capable of predicting properties of systems containing anions that were not part of the training set of the model. Furthermore, it is demonstrated that the model can also lead to satisfying predictions if compared to vapor-liquid equilibrium data. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-20T10:15:51.376791-05:
      DOI: 10.1002/aic.15875
  • A Rigorous Method to Evaluate the Consistency of Experimental Data in
           Phase Equilibria. Application to VLE and VLLE
    • Authors: Luís J. Fernández; Juan Ortega, Jaime Wisniak
      Abstract: This work forms part of a broader study that describes a methodology to validate experimental data of phase equilibria for multicomponent systems from a thermodynamic-mathematical perspective. The goal of this paper is to present and justify this method and to study its application to vapor-liquid equilibria (VLE) and vapor-liquid-liquid equilibria (VLLE), obtained under isobaric/isothermal conditions. A procedure based on the Gibbs-Duhem equation is established which presents two independent calculation paths for its resolution: (a) an integral method and (b) a differential method. Functions are generated for both cases that establish the verification or consistency of data, δψ for the integral test and δζ for the differential approach, which are statistically evaluated by their corresponding average values [δψ¯, δζ¯], and the standard deviations [s(δψ), s(δϛ)]. The evaluation of these parameters for application to real cases is carried out using a set of hypothetical systems (with data generated artificially), for which the values are adequately changed to determine their influence on the method. In this way, the requirements of the proposed method for the data are evaluated and their behavior in response to any disruption in the canonical variables (p,T, phase compositions). The conditions for thermodynamic consistency of data are: δψ¯
      PubDate: 2017-07-20T10:15:46.321288-05:
      DOI: 10.1002/aic.15876
  • Sustainable Biopolymer Synthesis via Superstructure and Multi-Objective
    • Authors: Ehecatl Antonio del Rio-Chanona; Dongda Zhang, Nilay Shah
      Abstract: Sustainable polymers derived from biomass have great potential to replace petrochemical based polymers and fulfill the ever-increasing market demand. To facilitate their industrialization, in this research, a comprehensive superstructure reaction network comprising a large number of reaction pathways from biomass to both commercialized and newly proposed polymers is constructed. To consider economic performance and environmental impact simultaneously, both process profit and green chemistry metrics are embedded into the multi-objective optimization framework, and MINLP is employed to enable the effective selection of promising biopolymer candidates. Through this proposed approach, the current study identifies the best biopolymer candidates and their most profitable and environmentally-friendly synthesis routes under different scenarios. Moreover, the stability of optimization results regarding the price of raw materials and polymers and the effect of process scale on the investment cost are discussed in detail. These results, therefore, pave the way for future research on the production of sustainable biopolymers. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-20T10:15:37.212697-05:
      DOI: 10.1002/aic.15877
  • Oxidation of Caffeine by Acid-activated Ferrate(VI): Effect of Ions and
           Natural Organic Matter
    • Authors: Kyriakos Manoli; George Nakhla, Ajay K. Ray, Virender K. Sharma
      Abstract: Caffeine (CAF) is the most commonly consumed stimulant and frequently detected emerging pollutant in influents and effluents of wastewater treatment plants (WWTP) and surface waters. Acid-activated ferrate(VI) (FeVIO42-, Fe(VI)) oxidizes CAF in water in seconds to minutes at three times lower molar ratio of Fe(VI) to CAF than oxidative transformation observed in hours by non-activated Fe(VI) (8.0 versus 25.0). CAF oxidation by acid-activated Fe(VI) is not affected by ionic constituents of water. Organic components of natural organic matter (NOM) and secondary effluent wastewater (SE) decrease efficiency of CAF transformation. However, acid-activated Fe(VI) could mineralize other organics present in both NOM and SE as indicated by the dissolved organic carbon (DOC) removal. Comparatively, no mineralization was seen without activation of Fe(VI). Four oxidized products of CAF were identified by a liquid chromatography high resolution mass spectrometry technique. The reaction pathways of the oxidation of CAF by activated Fe(VI) have been proposed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-20T10:15:31.534913-05:
      DOI: 10.1002/aic.15878
  • Some mechanistic insights into the action of facilitating agents on gas
           permeation through glassy polymeric membranes
    • Authors: Md Oayes Midda; Akkihebbal K Suresh
      Abstract: Incorporation of facilitating agents is one of the promising strategies being researched in recent years to cross the Robeson bounds for gas separations using polymeric membranes. The ways in which such inclusions modify the performance of membranes are not always clear. Here, we study the performance of two glassy membranes, Polyfurfuryl alcohol and Polysulfone, in O2/N2 and CO2/N2 separations, with Cobalt phthalocyanin in insoluble and solubilized forms as the facilitating agent. The results show that in general, three effects are important: (i) a barrier effect, (ii) a facilitation effect and (iii) morphological effects on the polymer matrix due to an incompatibility between the particles and the polymer. These results provide some insight into the action of facilitating agents in soluble and insoluble form, when used as membrane additives. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-20T10:10:35.9034-05:00
      DOI: 10.1002/aic.15873
  • Dynamic Modeling and Simulations of the Behavior of a Fixed-Bed
           Reactor-Exchanger used for CO2 Methanation
    • Authors: Rasmey Try; Alain Bengaouer, Pierre Baurens, Christian Jallut
      Abstract: A multidimensional heterogeneous and dynamic model of a fixed-bed heat exchanger reactor used for CO2 methanation has been developed in this work that is based on mass, energy and momentum balances in the gas phase and mass and energy balances for the catalyst phase. The dynamic behavior of this reactor is simulated for transient variations in inlet gas temperature, cooling temperature, gas inlet flow rate and outlet pressure. Simulation results showed that wrong-way behaviors can occur for any abrupt temperature changes. Conversely, temperature ramp changes enable to attenuate and even fade the wrong-way behavior. Traveling hot spots appear only when the change of an operating condition shifts the reactor from an ignited steady state to a non-ignited one. Inlet gas flow rate variations reveal overshoots and undershoots of the reactor maximum temperature. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-20T10:10:25.956822-05:
      DOI: 10.1002/aic.15874
  • Modular Manufacturing Processes: Status, Challenges and Opportunities
    • Authors: Michael Baldea; Thomas F. Edgar, Bill L. Stanley, Anton A. Kiss
      Abstract: Chemical companies are constantly seeking new, high-margin growth opportunities, the majority of which lie in high-grade, specialty chemicals, rather than in the bulk sector. In order to realize these opportunities, manufacturers are increasingly considering decentralized, flexible production facilities: large-scale production units are uneconomical for innovative products with a short lifespan and volatile markets. Small modular plants have low financial risks, are flexible and can respond rapidly to changes in demand. Logistics costs can be also reduced by moving production closer to customers and/or sources of raw materials. Moreover, stricter safety regulations can in many cases be more easily met using smaller distributed facilities.Modularization of chemical production can thus have potentially significant economic and safety ben- efits. In this article, we review several drivers for modular production, and evaluate modular production architectures based on the value density of feedstock resources and markets for the products of a process. We also discuss the links between modularization and process intensification. We illustrate the discussion with an array of industrial examples, which we also use to motivate a summary of challenges and future directions for this area. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-18T10:55:37.449298-05:
      DOI: 10.1002/aic.15872
  • COSMO-based computer-aided molecular/mixture design: A focus on reaction
    • Authors: Nick D. Austin; Nikolaos V. Sahinidis, Ivan A. Konstantinov, Daniel W. Trahan
      Abstract: In this article, we investigate reaction solvent design using COSMO-RS thermodynamics in conjunction with computer-aided molecular design (CAMD) techniques. CAMD using COSMO-RS has the distinct advantage of being a method based in quantum chemistry, which allows for the incorporation of quantum-level information about transition states, reactive intermediates, and other important species directly into CAMD problems. This work encompasses three main additions to our previous framework for solvent design1: (1) altering the group contribution method to estimate hydrogen-bonding and non-hydrogen-bonding σ-profiles; (2) ab initio modeling of strong solute/solvent interactions such as H-bonding or coordinate bonding; and (3) solving mixture design problems limited to common laboratory and industrial solvents. We apply this methodology to three diverse case studies: accelerating the reaction rate of a Menschutkin reaction, controlling the chemoselectivity of a lithiation reaction, and controlling the chemoselectivity of a nucleophilic aromatic substitution reaction. We report improved solvents/mixtures in all cases. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-13T03:30:21.889893-05:
      DOI: 10.1002/aic.15871
  • Biochar Soil Amendments for Increased Crop Yields: How to design a
           “designer” biochar
    • Authors: Kyriacos Zygourakis
      Abstract: This study presents the development and testing of a transient adsorption/desorption model that describes the response of biochar particles to nutrient pulses simulating the application of fertilizer. Intraparticle nutrient transfer occurs both by diffusion through liquid-filled pores and by surface diffusion, and nutrient adsorption is described by Langmuir-Freundlich (Sips) isotherms. Simulation results show that the ability of a biochar to adsorb and then slowly release the nutrient is modulated by a complex interplay of external mass transfer, intraparticle diffusion (both pore and surface diffusion), and adsorption dynamics. The nutrient retention potential of biochar-amended soils is quantified and is shown to depend on multiple factors that include chemical and physical biochar properties, soil permeability, water flow and the method of fertilizer application. These findings may explain why biochars with similar properties can potentially have widely different impacts on crop yields, as has been repeatedly reported in the literature. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-12T13:10:21.010583-05:
      DOI: 10.1002/aic.15870
  • Design and Assessment of Delay Timer Alarm Systems for Nonlinear Chemical
    • Authors: Aditya Tulsyan; Feras Alrowaie, R. Bhushan Gopaluni
      Abstract: In process and manufacturing industries, alarm systems play a critical role in ensuring safe and efficient operations. The objective of a standard industrial alarm system is to detect undesirable deviations in process variables as soon as they occur. Fault detection and diagnosis (FDD) systems often need to be alerted by an industrial alarm system; however, poorly designed alarms often lead to alarm flooding and other undesirable events. In this paper, we consider the problem of industrial alarm design for processes represented by stochastic nonlinear time-series models. The alarm design for such complex processes faces three important challenges: 1) industrial processes exhibit highly nonlinear behavior; 2) state variables are not precisely known (modeling error); and 3) process signals are not necessarily Gaussian, stationary or uncorrelated. In this paper, a procedure for designing a delay timer alarm configuration is proposed for the process states. The proposed design is based on minimization of the rate of false and missed alarm rates – two common performance measures for alarm systems. To ensure the alarm design is robust to any non-stationary process behavior, an expected-case and a worst-case alarm designs are proposed. Finally, the efficacy of the proposed alarm design is illustrated on a non-stationary chemical reactor problem. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T11:05:08.150056-05:
      DOI: 10.1002/aic.15860
  • Generalized Gibbs Free Energy of Confined Nanoparticles
    • Authors: Nanhua Wu; Xiaoyan Ji, Rong An, Chang Liu, Xiaohua Lu
      Abstract: The nanoparticles generally show abnormal properties compared to those in the bulk phase, and they exhibit significant potential in various applications such as catalysis and energy conversion. However, the theoretical work for describing the properties of nanoparticles is limited with poor prediction capacity. In this work, the Gibbs free energy was studied, from both macroscope and microscope, predictive models were proposed to study the thermodynamic properties of nanoparticles with a generalized description of the Gibbs free energy considering the effects of surface-energy and the substrate contacted. The proposed model from the microscope was based on the corresponding states theory to describe the effect of the substrate on the Gibbs free energy of nanoparticles, in which the molecular parameter with a generalized constant was obtained from the melting point of metals due to sufficient experimental information. The comparison with the new measured experimental results proves the reliability of the model prediction. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T10:41:50.101726-05:
      DOI: 10.1002/aic.15861
  • Pressure drop and saturation of non-wettable coalescing filters at
           different loading rates
    • Authors: Cheng Chang; Zhongli Ji, Jialin Liu
      Abstract: The effect of layers on the pressure drop and saturation of non-wettable filters at different loading rates were investigated. It was found that both the jump and channel pressure drop depended on the loading rate. The total channel pressure drop of different filters seemed independent of the number of layers. At the same loading rate, more layers led to fewer channels per layer and larger size of each channel. Moreover, according to the evolution of channel number and size, there was a reorganization of channel structure in the filters. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T10:41:12.627436-05:
      DOI: 10.1002/aic.15863
  • 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
  • Issue information - table of contents
    • Pages: 4261 - 4261
      PubDate: 2017-09-04T11:09:16.874767-05:
      DOI: 10.1002/aic.15480
  • Enhancing oxygen permeation via multiple types of oxygen transport paths
           in hepta-bore perovskite hollow fibers
    • Authors: Jiawei Zhu; Tianlei Wang, Zhe Song, Zhengkun Liu, Guangru Zhang, Wanqin Jin
      Pages: 4273 - 4277
      Abstract: The multiple types of efficient oxygen transport paths were demonstrated in high-mechanical-strength hepta-bore Ba0.5Sr0.5Co0.8Fe0.2O3-δ hollow fiber membranes. These types of paths play a prominent role in enhancing oxygen permeation fluxes (17.6 mL min−1 cm−2 at 1223 K) which greatly transcend the performance of state-of-the-art Ba0.5Sr0.5Co0.8Fe0.2O3-δ hollow fiber membranes, showing a good commercialization prospect. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4273–4277, 2017
      PubDate: 2017-07-12T13:35:26.054349-05:
      DOI: 10.1002/aic.15849
  • 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
      Pages: 4278 - 4286
      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 nonoil biomass were monitored as proxies for the consumption of nitrogen and lipid accumulation status, which was first applied to divided fermentation process with three 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. A multistage control strategy is subsequently implemented 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4278–4286, 2017
      PubDate: 2017-05-14T18:06:08.755974-05:
      DOI: 10.1002/aic.15783
  • 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
      Pages: 4287 - 4295
      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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4287–4295, 2017
      PubDate: 2017-05-27T18:25:26.521108-05:
      DOI: 10.1002/aic.15649
  • Influence of adhesion on random loose packings of binary microparticle
    • Authors: Wenwei Liu; Sheng Chen, Shuiqing Li
      Pages: 4296 - 4306
      Abstract: Binary adhesive packings of microspheres with certain size ratios are investigated via a 3-D 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 used 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 to give a better understanding of such adhesive binary packings. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4296–4306, 2017
      PubDate: 2017-05-12T08:53:33.540137-05:
      DOI: 10.1002/aic.15775
  • An experimental study of the flow of nonspherical grains in a rotating
    • Authors: Sandip Mandal; Devang V. Khakhar
      Pages: 4307 - 4315
      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 used 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 nonspherical 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4307–4315, 2017
      PubDate: 2017-05-13T12:05:32.990344-05:
      DOI: 10.1002/aic.15772
  • Mixing dynamics in bubbling fluidized beds
    • Authors: A. Bakshi; A. F. Ghoniem, C. Altantzis
      Pages: 4316 - 4328
      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 computational fluid dynamics simulations. Toward 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4316–4328, 2017
      PubDate: 2017-05-31T09:25:30.973291-05:
      DOI: 10.1002/aic.15801
  • Distributed output-feedback fault detection and isolation of cascade
           process networks
    • Authors: Xunyuan Yin; Jinfeng Liu
      Pages: 4329 - 4342
      Abstract: Distributed output-feedback fault detection and isolation (FDI) of nonlinear cascade process networks that can be divided into subsystems is considered. 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4329–4342, 2017
      PubDate: 2017-05-23T12:55:36.024161-05:
      DOI: 10.1002/aic.15791
  • A data-driven multistage adaptive robust optimization framework for
           planning and scheduling under uncertainty
    • Authors: Chao Ning; Fengqi You
      Pages: 4343 - 4369
      Abstract: A novel data-driven approach for optimization under uncertainty based on multistage adaptive robust optimization (ARO) and nonparametric kernel density M-estimation is proposed. 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 reweighted least squares algorithm. A data-driven uncertainty set is proposed, where bounds of uncertain parameters are defined by quantile functions, 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4343–4369, 2017
      PubDate: 2017-05-24T11:10:35.219877-05:
      DOI: 10.1002/aic.15792
  • Two-dimensional modeling of an absorbing falling film in its development
    • Authors: Christophe Wylock; Benoit Scheid
      Pages: 4370 - 4378
      Abstract: This work presents the modeling 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, one dimensional (1-D) second-order weighted integral boundary layer (WIBL) model is shown to accurately reproduce the film deformations. The gas transfer is then solved in a 2-D predeformed domain 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 perpendicular to the interface. On the contrary, a slight hindrance of the mass transfer is observed when the film is shrinking, although it remains in this case very close to the flat film analytical solution. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4370–4378, 2017
      PubDate: 2017-06-07T12:45:26.194487-05:
      DOI: 10.1002/aic.15808
  • Gravity induced coalescence in emulsions with high volume fractions of
           dispersed phase in the presence of surfactants
    • Authors: Meenakshi Mazumdar; Shantanu Roy
      Pages: 4379 - 4389
      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 examining the droplet size distribution under the microscope. Experiments were performed 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 was delayed. At higher surfactant concentrations (1.6%), the dominant factor in suppressing destabilization is the rate of drop to interface coalescence. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4379–4389, 2017
      PubDate: 2017-06-10T20:55:26.472197-05:
      DOI: 10.1002/aic.15803
  • 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
      Pages: 4403 - 4417
      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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4403–4417, 2017
      PubDate: 2017-05-12T08:47:50.096311-05:
      DOI: 10.1002/aic.15773
  • Direct nonoxidative conversion of methane to hydrogen and higher
           hydrocarbons by dielectric barrier discharge plasma with plasma catalysis
    • Authors: Elijah Chiremba; Kui Zhang, Canan Kazak, Galip Akay
      Pages: 4418 - 4429
      Abstract: Direct nonoxidative conversion of methane to hydrogen and hydrocarbons was achieved at atmospheric pressure and 120°C using nonthermal 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 nonoxidative catalytic methane conversion at ca. 1000°C. Therefore, these results represent process intensification in methane conversion. PCPs underwent structural and chemical changes but their performances are not affected during an 80-h experimental period. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4418–4429, 2017
      PubDate: 2017-05-16T20:15:38.513847-05:
      DOI: 10.1002/aic.15769
  • 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
      Pages: 4430 - 4441
      Abstract: A series of core-shell structural deNOx catalysts using small-grain Beta supporting FeOx nanoparticles 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4430–4441, 2017
      PubDate: 2017-05-24T13:15:30.929182-05:
      DOI: 10.1002/aic.15743
  • NMR spectroscopic study of chemical equilibria in solutions of
           formaldehyde, water, and butynediol
    • Authors: Jürgen Berje; Jakob Burger, Hans Hasse, Jens Baldamus
      Pages: 4442 - 4450
      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 to 366 K, overall formaldehyde mass fractions from 0.10 to 0.27 g g−1, and overall butynediol mass fractions from 0.05 to 0.50 g g−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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4442–4450, 2017
      PubDate: 2017-05-26T18:50:29.573573-05:
      DOI: 10.1002/aic.15788
  • 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
      Pages: 4451 - 4464
      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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4451–4464, 2017
      PubDate: 2017-05-27T18:05:36.764956-05:
      DOI: 10.1002/aic.15796
  • 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
      Pages: 4465 - 4475
      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 1–2 M), temperature (in the range of 298–333 K), and CO2 partial pressure (in the range of 8–101 kPa). 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4465–4475, 2017
      PubDate: 2017-05-31T09:21:06.044427-05:
      DOI: 10.1002/aic.15797
  • 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
      Pages: 4476 - 4490
      Abstract: The size of a silica supported metallocene/MAO (methylaluminoxane) 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 this 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 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4476–4490, 2017
      PubDate: 2017-06-05T14:40:32.96015-05:0
      DOI: 10.1002/aic.15806
  • Gas permeation properties for organosilica membranes with different Si/C
           ratios and evaluation of microporous structures
    • Authors: Masakoto Kanezashi; Yuri Yoneda, Hiroki Nagasawa, Toshinori Tsuru, Kazuki Yamamoto, Joji Ohshita
      Pages: 4491 - 4498
      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 to 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4491–4498, 2017
      PubDate: 2017-05-12T08:11:53.840985-05:
      DOI: 10.1002/aic.15778
  • Impact of osmotic agent on the transport of components using forward
           osmosis to separate ethanol from aqueous solutions
    • Authors: Alan Ambrosi; Guilherme Lopes Corrêa, Natiéli Souza de Vargas, Lucas Martim Gabe, Nilo Sérgio Medeiros Cardozo, Isabel Cristina Tessaro
      Pages: 4499 - 4507
      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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4499–4507, 2017
      PubDate: 2017-05-14T17:55:51.701814-05:
      DOI: 10.1002/aic.15779
  • Function and effect of the inner vortex on the performance of cyclone
    • Authors: Bo Wang; Binbin Pei, He Liu, Yunchao Jiang, Delong Xu, Yanxin Chen
      Pages: 4508 - 4518
      Abstract: The inner vortex plays a key role in the performance of cyclone separators. 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. First, 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4508–4518, 2017
      PubDate: 2017-05-16T20:20:33.255334-05:
      DOI: 10.1002/aic.15780
  • Modeling and process simulation of hollow fiber membrane reactor systems
           for propane dehydrogenation
    • Authors: Seung-Won Choi; David S. Sholl, Sankar Nair, Jason S. Moore, Yujun Liu, Ravindra S. Dixit, John G. Pendergast
      Pages: 4519 - 4531
      Abstract: We report a detailed modeling analysis of membrane reactor systems for propane dehydrogenation (PDH), by integrating a two-dimensional (2-D) nonisothermal model of a packed bed membrane reactor (PBMR) with ASPEN process simulations for the overall PDH plant including downstream separations processes. PBMRs based on 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4519–4531, 2017
      PubDate: 2017-05-18T09:35:30.826115-05:
      DOI: 10.1002/aic.15785
  • 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, Bin Mu, Zhenfei Cheng, Jichang Liu
      Pages: 4532 - 4540
      Abstract: In this study, a new cobalt-based metal-organic framework (MOF), [Co6II(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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4532–4540, 2017
      PubDate: 2017-05-18T09:40:26.212089-05:
      DOI: 10.1002/aic.15786
  • Polyethyleneimine-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
      Pages: 4541 - 4548
      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 30 k wt % behaved excellently with microsphere rejection and Co(II) adsorption reaching 98.5% and 51.0 mg/g, respectively. They successfully decreased Co(II) concentration from 3.0 mg/L to the allowable discharge standard (0.5 mg/L), even with an enhanced flux of 6200 L/m2/h at 0.12 MPa under the cyclic tests. Overall, PEI-grafted membrane adsorption is highly efficient for removing HMIs and suspended particles simultaneously from wastewater. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4541–4548, 2017
      PubDate: 2017-05-24T10:55:40.780176-05:
      DOI: 10.1002/aic.15789
  • 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
      Pages: 4549 - 4563
      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 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4549–4563, 2017
      PubDate: 2017-05-27T18:15:29.416277-05:
      DOI: 10.1002/aic.15795
  • 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
      Pages: 4564 - 4575
      Abstract: We use multiscale modeling to study how the molecular properties of a protein affect its adsorption and transport in ion exchange 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, and immunoglobulin 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4564–4575, 2017
      PubDate: 2017-05-27T18:30:27.324314-05:
      DOI: 10.1002/aic.15798
  • Predicting solvent effects on the 1-dodecene hydroformylation reaction
    • Authors: Max Lemberg; Gabriele Sadowski, Martin Gerlach, Emilija Kohls, Matthias Stein, Christof Hamel, Andreas Seidel-Morgenstern
      Pages: 4576 - 4585
      Abstract: Solvent effects on the reaction equilibrium of the 1-dodecene hydroformylation in a decane/N,N-dimethylformamide solvent system is investigated. 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, 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4576–4585, 2017
      PubDate: 2017-05-15T14:30:36.240656-05:
      DOI: 10.1002/aic.15782
  • Molecular transport through mixed matrix membranes: A time-dependent
           density functional approach
    • Authors: Yu Liu; Fangyuan Guo, Jun Hu, Honglai Liu, Ying Hu
      Pages: 4586 - 4594
      Abstract: The transport properties of gases in mixed matrix membranes (MMMs) are important in materials design. Here, a novel time-dependent density functional theory (TDDFT) method to study the transport properties of gases in MMMs is developed. 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. TDDFT prediction of the permeation is found to be 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4586–4594, 2017
      PubDate: 2017-06-05T14:35:37.803196-05:
      DOI: 10.1002/aic.15805
  • A multicontinuum approach for the problem of filtration of oily water
           systems across thin flat membranes: I. The framework
    • Authors: Amgad Salama; Mohamed Zoubeik, Amr Henni
      Pages: 4604 - 4615
      Abstract: A multicontinuum model is built to estimate the permeate flux of an oily water system across a thin flat membrane in cross filtration methodology is demonstrated. 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 multicontinuum approach, which is introduced in this first part. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4604–4615, 2017
      PubDate: 2017-05-13T12:00:33.522587-05:
      DOI: 10.1002/aic.15784
  • Capillary driven flow in wettability altered microchannel
    • Authors: Ayantika Sett; Uzma Bano, Sunando DasGupta, Debasish Sarkar, Arijit Mitra, Siddhartha Das, Swagata Dasgupta
      Pages: 4616 - 4627
      Abstract: The capillary driven flow of water inside a microchannel with altered wettabilities is experimentally investigated and modeled 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4616–4627, 2017
      PubDate: 2017-05-18T09:45:32.347382-05:
      DOI: 10.1002/aic.15787
  • Simulation of deformable preformed particle gel propagation in porous
    • Authors: Jing Wang; Hui-Qing Liu, Hong-ling Zhang, Kamy Sepehrnoori
      Pages: 4628 - 4641
      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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4628–4641, 2017
      PubDate: 2017-05-24T10:55:35.150653-05:
      DOI: 10.1002/aic.15793
  • A critical review of statistical calibration/prediction models handling
           data inconsistency and model inadequacy
    • Authors: Pascal Pernot; Fabien Cailliez
      Pages: 4642 - 4665
      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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4642–4665, 2017
      PubDate: 2017-05-26T18:45:34.471-05:00
      DOI: 10.1002/aic.15781
  • Time-resolved ultrasonic spectroscopy for bubbles
    • Authors: Valentin Leroy; Anatoliy Strybulevych, Tomohisa Norisuye
      Pages: 4666 - 4672
      Abstract: We show that ultrasound can provide time-resolved measurements of the size 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4666–4672, 2017
      PubDate: 2017-05-27T18:10:27.225215-05:
      DOI: 10.1002/aic.15799
  • Particle-laden liquid jet impingement on a moving substrate
    • Authors: Hatef Rahmani; Sheldon I. Green
      Pages: 4673 - 4684
      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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4673–4684, 2017
      PubDate: 2017-06-01T13:20:49.587571-05:
      DOI: 10.1002/aic.15800
  • Indirect conduction in gas–solids systems: Static vs. Dynamic
    • Authors: Aaron M. Lattanzi; Christine M. Hrenya
      Pages: 4685 - 4693
      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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4685–4693, 2017
      PubDate: 2017-06-01T10:10:35.157805-05:
      DOI: 10.1002/aic.15802
  • Hydrodynamics of gas–liquid flow in micropacked beds: Pressure drop,
           liquid holdup, and two-phase model
    • Authors: Jisong Zhang; Andrew R. Teixeira, Lars Thilo Kögl, Lu Yang, Klavs F. Jensen
      Pages: 4694 - 4704
      Abstract: Hydrodynamics of gas–liquid two-phase flow in micropacked 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 microsystems, 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 micropacked beds by considering the contribution of capillary forces, and its predictions are in good agreement with experimental data. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4694–4704, 2017
      PubDate: 2017-06-06T10:30:30.602511-05:
      DOI: 10.1002/aic.15807
  • Sonochemical effect induced by hydrodynamic cavitation: Comparison of
           venturi/orifice flow geometries
    • Authors: Sandip K. Pawar; Amit V. Mahulkar, Aniruddha B. Pandit, Kuldeep Roy, Vijayanand S. Moholkar
      Pages: 4705 - 4716
      Abstract: This study presents comparative assessment of four cavitation devices (three venturis and an orifice) in terms of cavitational yield. A fourfold 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 interbubble coalescence and recombination of oxidizing radicals generated from cavitation bubbles. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4705–4716, 2017
      PubDate: 2017-06-12T14:16:16.767407-05:
      DOI: 10.1002/aic.15812
  • Comment on Xu et al. 2017
    • Authors: Christopher J. Landry; Maša Prodanović, Peter Eichhubl
      Pages: 4717 - 4718
      PubDate: 2017-06-21T19:05:30.795978-05:
      DOI: 10.1002/aic.15823
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