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  Subjects -> ENGINEERING (Total: 2272 journals)
    - CHEMICAL ENGINEERING (190 journals)
    - CIVIL ENGINEERING (183 journals)
    - ELECTRICAL ENGINEERING (102 journals)
    - ENGINEERING (1204 journals)
    - ENGINEERING MECHANICS AND MATERIALS (381 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (68 journals)
    - MECHANICAL ENGINEERING (89 journals)

ENGINEERING (1204 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: 17)
AAPG Bulletin     Hybrid Journal   (Followers: 7)
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: 245)
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: 8)
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: 16)
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: 22)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 29)
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: 31)
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: 17)
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: 16)
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   (Followers: 1)
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)
Asia-Pacific Journal of Science and Technology     Open Access  
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: 5)
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: 32)
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   (Followers: 1)
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: 9)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 22)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 43)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
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: 7)
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: 22)
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: 4)
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: 266)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 185)
Composites Part B : Engineering     Hybrid Journal   (Followers: 278)
Composites Science and Technology     Hybrid Journal   (Followers: 180)
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: 7)
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: 7)
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   (Followers: 1)
CTheory     Open Access  

        1 2 3 4 5 6 7 | Last

Journal Cover AIChE Journal
  [SJR: 1.122]   [H-I: 120]   [31 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  [1579 journals]
  • Robust Stabilization of a Two-Stage Continuous Anaerobic Bioreactor System
    • Authors: Zhaoyang Duan; Costas Kravaris
      Abstract: This paper studies the problem of stabilizing a two-stage continuous bioreactor system. A simple dynamic model of the system is first introduced based on a detailed mass balance model, and then used to derive a constant-yield controller to stabilize the system at given design steady state conditions. Using Lyapunov stability analysis, this control law is proved to guarantee stability of the closed loop system over the entire positive orthant. Simulation results show the successful performance of the controller. The control law is proved to be robust with respect to errors in the kinetic parameters and in the inlet feed concentration, in the sense of preserving its stability region. Performance of the control system can be enhanced if a feedforward measurement of the inlet feed concentration can be incorporated in the control law. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-14T10:55:41.235266-05:
      DOI: 10.1002/aic.16033
       
  • Mixed-Cation LiCa-LSX Zeolite with Minimum Lithium for Air Separation
    • Authors: Franklin E. Epiepang; Xiong Yang, Jianbo Li, Yingshu Liu, Ralph T. Yang
      Abstract: The aim of this work was to reduce/minimize Li in Li-LSX by replacing the 70% Li+ cations in Li-LSX that are bonded to the interior or inaccessible sites which are not used for adsorption. Thus, mixed-cation LiCa-LSX containing minimum lithium were prepared by exchanging small fractions of Li+ into Ca-LSX, followed by dehydration under mild conditions to avoid migration/equilibration of Li+ cations. Comparisons of adsorption isotherms of N2/O2 and heats of adsorption for the LiCa-LSX samples with that for pure-cation Li-LSX and Ca-LSX provided strong evidence that significant amounts of these Li+ cations indeed remained on the exposed sites (SIII). The mixed-cation LiCa-LSX samples were compared against the pure-cation Ca-LSX and Li-LSX based on their performance for oxygen production by PSA, via model simulation. The results showed that the mixed-cation LiCa-LSX samples yielded significantly higher O2 product productivities at the same product purity and recovery than their pure-cation precursor (Ca-LSX). This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-14T10:55:36.79446-05:0
      DOI: 10.1002/aic.16032
       
  • Modeling of Circulating Fluidized Beds systems for post-combustion CO2
           capture via Temperature Swing Adsorption
    • Authors: Stefano E. Zanco; Matteo Gazzani, Matteo C. Romano, Isabel Martínez, Marco Mazzotti
      Abstract: The technology of circulating uidized beds (CFB) is applied to temperature swing adsorption (TSA) processes for post-combustion CO2 capture employing a commercial zeolite sorbent. Steady state operation is simulated through a one-dimensional model, which combines binary adsorption with the CFB dynamics. Both single step and multi-step arrangements are investigated. Extensive sensitivity analyses are performed varying the operating conditions, in order to assess the inuence of the main operational parameters. The results reveal a neat superiority of multi-step configurations over the standard one, in terms of both separation performance and efficiency. Compared to fixed-bed TSA systems, CFB TSA features a high compactness degree. However, product purity levels are limited compared to the best performing fixed-bed processes, and heat management within the system appears to be a major issue. As regards energy efficiency, CFB systems place themselves in between the most established absorption-based technologies and the fixed-bed TSA. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-14T10:50:38.062582-05:
      DOI: 10.1002/aic.16029
       
  • Feedback control of proppant bank heights during hydraulic fracturing for
           enhanced productivity in shale formations
    • Authors: Prashanth Siddhamshetty; Joseph Sang-II Kwon, Shuai Liu, Peter P. Valkó
      Abstract: In hydraulic fracturing of shale formations, compared to conventional reservoirs, the fracturing fluid injected is of low-viscosity and hence during pumping the proppant settles significantly, forming a proppant bank. Motivated by this consideration, we initially develop a high-fidelity process model of hydraulic fracturing to describe the dominant proppant settling behavior during hydraulic fracturing. Second, a novel remeshing strategy is developed to handle the high computational requirement due to moving boundaries. Third, a section-based optimization method is employed to obtain key fracture design parameters for enhanced productivity in shale formations subject to given fracturing resources. Fourth, a reduced-order model is constructed to design a Kalman filter and to synthesize a real-time model-based feedback control system by explicitly taking into account actuator limitations, process safety and economic considerations. We demonstrate that the proposed control scheme can regulate the uniformity of proppant bank heights along the fracture at the end of pumping. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-14T10:50:30.307892-05:
      DOI: 10.1002/aic.16031
       
  • Optimal PID Controller Tuning using Stochastic Programming Techniques
    • Authors: Jose A. Renteria; Yankai Cao, Alexander W. Dowling, Victor M. Zavala
      Abstract: We argue that stochastic programming provides a powerful framework to tune and analyze the performance limits of controllers. In particular, stochastic programming formulations can be used to identify controller settings that remain robust across diverse scenarios (disturbances, set-points, and modeling errors) observed in real-time operations. We also discuss how to use historical data and sampling techniques to construct operational scenarios and inference analysis techniques to provide statistical guarantees on limiting controller performance. Under the proposed framework, it is also possible to use risk metrics to handle extreme (rare) events and stochastic dominance concepts to conduct systematic benchmarking studies. We provide numerical studies to illustrate the concepts and to demonstrate that modern modeling and local/global optimization tools can tackle large-scale applications. The proposed work also opens the door to data-based controller tuning strategies that can be implemented in real-time operations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-11T09:50:21.698851-05:
      DOI: 10.1002/aic.16030
       
  • Optimal Operation of Batch Enantiomer Crystallization: From Ternary
           Diagrams to Predictive Control
    • Authors: Caio Felippe Curitiba Marcellos; Helen Durand, Joseph Sang-II Kwon, Amaro Gomes Barreto, Paulo Laranjeira da Cunha Lage, Maurício Bezerra de Souza, Argimiro Resende Secchi, Panagiotis D. Christofides
      Abstract: In this work, the modeling and control of batch crystallization for racemic compound forming systems is addressed in a systematic fashion. Specifically, a batch crystallization process is considered for which the initial solution has been pre-enriched in the desired enantiomer to enable crystallization of only the preferred enantiomer. A method for determining desired operating conditions (composition of the initial pre-enriched solution and temperature to which the mixture must be cooled for maximum yield) for the batch crystallizer based on a ternary diagram for the enantiomer mixture in a solvent is described. Subsequently, it is shown that the information obtained from the ternary diagram, such as the maximum yield attainable from the process due to thermodynamics, can be used to formulate constraints for an optimization-based control method to achieve desired product characteristics such as a desired yield. The proposed method is demonstrated for the batch crystallization of mandelic acid in a crystallizer with a fines trap that is seeded with crystals of the desired enantiomer. The process is controlled with an optimization-based controller to minimize the ratio of the mass of crystals obtained from nuclei to the mass obtained from seeds while maintaining the desired enantioseparation. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-10T11:05:24.444146-05:
      DOI: 10.1002/aic.16028
       
  • More Comprehensive 3D Modeling of Clay-like Material Drying
    • Authors: M. Heydari; K. Khalili, S. Y. Ahmadi-Brooghani
      Abstract: Drying process plays an important role in the manufacturing of many products such as ceramic, kitchenware and building materials, some of which have complex 3D geometry. To deal with many restrictions found in literatures, a 3D numerical approach was used to describe the drying process of a porous Clay-like material. The problem investigated involves highly coupled equations considering heat, mass and mechanical aspects. The model is validated through the comparison of experimental measurements with simulation result. Simulation results show that increasing the initial moisture content and reducing the initial temperature have the same privilege and without significant increase in drying time, it reduces slightly the amount of maximum stress but delays the occurrence time of maximum stress. The non-uniform heat expansion induced stresses are very small in comparison to non-uniform moisture shrinkage induced stresses and can be neglected in drying simulation. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-10T10:10:20.229176-05:
      DOI: 10.1002/aic.16027
       
  • Numerical Simulation on Flow Behaviour of Twin-liquid Films over a
           Vertical Plate with an Open Window
    • Authors: Hanguang Xie; Jianguang Hu, Gance Dai
      Abstract: A novel element for gas–liquid contact, a plate with rectangular windows was designed to enhance absorption process. Coexistence and interaction of wall-bounded films and confined free films named as “twin-liquid films” were observed on the plate. VOF method was used to simulate its flow behavior. Flow phenomena such as flow around a step-in, jet impingement, varicose waves, and sinuous waves were observed. Different from thin films flow on an unperforated plate, larger mean velocity, thinner film thickness, more intensive capillary waves, and stronger vorticity on the free surfaces were detected inside the window, and the disturbances could propagate over the whole plate. Three-dimensional simulation results generally agreed with our experimental observations and further demonstrated complex wavy structures both inside and outside the window. The results would broaden traditional knowledge of liquid films flow and clarify the mechanism of mass transfer intensification for the plate with windows. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-08T11:20:42.379766-05:
      DOI: 10.1002/aic.16021
       
  • Materials Genomics-Guided Ab Initio Screening of MOFs with Open Copper
           Sites for Acetylene Storage
    • Authors: Ce Zhang; Youshi Lan, Xiangyu Guo, Qingyuan Yang, Chongli Zhong
      Abstract: Discovering high-performance metal-organic frameworks (MOFs) with open metal sites has become an increasingly hot research topic in the field of safe storage and transportation of acetylene. Following the concept of Materials Genomics proposed recently, a database of 502 experimental MOFs was built by searching the structures deposited in the CSD with the dicopper paddle-wheel node Cu2(COO)4 as the characteristic materials gene. On the basis of the developed ab initio force field, a high-throughput computational screening was conducted to examine the property-performance relationships of MOFs containing Cu-OMS for C2H2 storage at ambient conditions. The optimal ranges of the structural and energetic features for the design of such MOFs were suggested. From our computational screening, three potentially promising MOFs were identified which exhibit a performance outperforming those MOFs reported experimentally so far with record high gravimetric C2H2 uptakes, both in the total and deliverable adsorption capacities. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-08T11:20:34.030147-05:
      DOI: 10.1002/aic.16025
       
  • DEM Study on the Discharge Characteristics of Lognormal Particle Size
           Distributions from a Conical Hopper
    • Authors: Ya Zhao; Shiliang Yang, Liangqi Zhang, Jia Wei Chew
      Abstract: This study employs the discrete element method (DEM) to investigate the impact of the widths of lognormal particle size distributions (PSDs) with the same mean particle diameter on hopper discharge behaviors, namely, discharge rate, particle velocities and size-segregation. Results reveal that (i) the hopper discharge rate decreases as PSD width increases; (ii) the mean discharge rates are constant with time, but the fluctuations increase as the PSD width increases; (iii) the overall size-segregation increases with PSD width; (iv) the overall mean particle diameters of the narrower PSDs do not exceed the initial mean of 5 mm, whereas that of wider ones do; (v) the relationship between PSD width and particle velocities is non-monotonic with no consistent trends; and (vi) no direct correlation exists between particle velocity and size-segregation. The results here provide valuable insights on the behavior of the prevalent polydisperse mixtures in hoppers. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-08T11:20:30.637498-05:
      DOI: 10.1002/aic.16026
       
  • Studies on Mild Catalytic Synthesis of Methyl Acrylate via One-Step Aldol
           Reaction
    • Authors: Gang Wang; Chidchon Sararuk, Zeng-xi Li, Chun-shan Li, Hui Wang, Suo-jiang Zhang
      Abstract: One-step catalytic synthesis of methyl acrylate from methyl acetate and trioxane, with 90.7% yield and 91.8% selectivity, was realized at 10°C-25°C. NMR analysis confirmed the ester enolization with generation of [i-Pr2EtN-H]+[TfO]- in the presence of i-Pr2EtN and Bu2BOTf, which was affected by solvent and base. The depolymerization of trioxane into formaldehyde was catalyzed by Bu2BOTf. The in-situ catalytic mechanism and efficiency of [i-Pr2EtN-H]+[TfO]- was determined and analyzed. Mechanism-based kinetic and thermodynamic studies were conducted for better understanding of this route. Also the primary process design and product separation simulation were carried out. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-08T01:15:52.329623-05:
      DOI: 10.1002/aic.16022
       
  • Synthesis of Ternary Distillation Process Structures Featuring Minimum
           Utility Cost Using the IDEAS Approach
    • Authors: Hiroshi Takase; Shinji Hasebe
      Abstract: A synthesis method for ternary distillation process structures is proposed on the basis of the infinite-dimensional state-space (IDEAS) approach. The proposed synthesis procedure consists of two steps. At the first step, the utility cost is minimized. The result of the first step contains many tiny flows among the modules because the number of flows is not included in the objective function. Then, at the second step, an evolutionary procedure for process simplification is executed. In this step, the weighted sum of flow rates is minimized recursively while updating the weights at each iteration. The practical process structure is finally determined from the result of the second simplification step. The developed synthesis procedure was applied to the separation problem of a ternary mixture consisting of benzene, toluene, and o-xylene. It demonstrated that the proposed procedure provides a process whose liquid composition profile is quite similar to that of a Petlyuk column. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-08T01:15:39.984478-05:
      DOI: 10.1002/aic.16023
       
  • A Comparative Kinetics Study of CO2 Absorption into Aqueous DEEA/MEA and
           DMEA/MEA Blended Solutions
    • Authors: Wusan Jiang; Xiayi Hu, Xiao Luo, Hongxia Gao, Zhiwu Liang, Bin Liu, Paitoon Tontiwachwuthikul
      Abstract: The kinetics of CO2 absorption into aqueous solutions of N,N-diethylethanolamine (DEEA), and N,N-dimethylethanolamine (DMEA), and their blends with monoethanolamine (MEA) have been studied in a stopped-flow apparatus. The kinetics experiments were carried out at the concentrations of DEEA and DMEA varying from 0.075 to 0.175 kmol/m3 respectively, and that of MEA ranging between 0.0075 and 0.0175 kmol/m3, over the temperature range of 293K to 313K. Two kinetics models are proposed to interpret the reaction in the blended amine systems and the results show that the model which incorporates the base-catalyzed hydration mechanism and termolecular mechanism resulted in a better prediction. Furthermore, the kinetics behaviors of CO2 absorption into two blended systems are comprehensively discussed according to their molecular structures. It can be concluded that the interaction between tertiary amines and primary amines as well as the alkyl chain length of tertiary amines have a significant influence on the kinetics. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-07T17:38:46.095241-05:
      DOI: 10.1002/aic.16024
       
  • Uncertainty-Conscious Methodology for Process Performance Assessment in
           Biopharmaceutical Drug Product Manufacturing
    • Authors: Gioele Casola; Christian Siegmund, Markus Mattern, Hirokazu Sugiyama
      Abstract: This work presents an uncertainty-conscious methodology for the assessment of process performance—e.g., run time—in the manufacturing of biopharmaceutical drug products. The methodology is presented as an activity model using the type 0 integrated definition (IDEF0) functional modelling method, which systematically interconnects information, tools, and activities. In executing the methodology, a hybrid stochastic–deterministic model that can reflect operational uncertainty in the assessment result is developed using Monte Carlo simulation. This model is used in a stochastic global sensitivity analysis to identify tasks that had large impacts on process performance under the existing operational uncertainty. Other factors are considered, such as the feasibility of process modification based on Good Manufacturing Practice, and tasks to be improved is identified as the overall output. In a case study on cleaning and sterilization processes, suggestions were produced that could reduce the mean total run time of the processes by up to 40%. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-06T17:21:56.05222-05:0
      DOI: 10.1002/aic.16020
       
  • A Branch and Bound Algorithm to Solve Large-Scale Multi-Stage Stochastic
           Programs with Endogenous Uncertainty
    • Authors: Brianna Christian; Selen Cremaschi
      Abstract: The growth in computation complexity of multistage stochastic programs (MSSPs) with problem size often prevents its application to real-world size problems. We present two variants of branch-and-bound algorithm, which reduce the resource requirements for the generation and solution of large-scale MSSPs with endogenous uncertainty. Both variants use Knapsack-problem based Decomposition Algorithm12 to generate feasible solutions and primal bounds. First variant (PH-KDA) uses a progressive hedging dual-bounding approach; the second (OSS-KDA) solves the MSSP removing all non-anticipativity constraints. Both variants were employed to solve several instances of the pharmaceutical clinical trial planning problem. The first iteration of both algorithms provide a feasible solution, and a primal bound and a dual bound for the problem. Although the dual-bounds of OSS-KDA were generally weaker than PH-KDA, they are generated considerably faster. For the seven-product case the OSS-KDA generated a solution with a gap of 9.92% in 115 CPU seconds. This article is protected by copyright. All rights reserved.
      PubDate: 2017-11-06T17:21:53.693542-05:
      DOI: 10.1002/aic.16019
       
  • Issue information
    • Abstract: Cover illustration. Photo of Roy Jackson taken around the time of his retirement from rinceton University; Eqs. 67 and 68 from his foundational paper in 1967, coauthored with Anderson, describing the momentumbalances for two-fluid model; image showing visualization of interaction of particles with boundary and the deduced momentum boundary condition (Eq. 2.10 from Johnson & Jackson, 1987); circulating flow inside a rising bubble (Anderson et al., 1994); his 2000 monograph; and title credit of his 1972 paper with Horn on mass action kinetics. Please see Introductory Retrospective for further details. 10.1002/aic.15981
      PubDate: 2017-11-02T11:29:41.317027-05:
      DOI: 10.1002/aic.15485
       
  • Food engineering into the XXI century
    • Authors: José Miguel Aguilera
      PubDate: 2017-10-30T10:30:21.799741-05:
      DOI: 10.1002/aic.16018
       
  • Insight in Kinetics from Pre-edge Features using Time Resolved in situ XAS
    • Authors: N.V.R.A. Dharanipragada; Vladimir V. Galvita, Hilde Poelman, Lukas C. Buelens, Alessandro Longo, Guy B. Marin
      Abstract: The kinetics of reduction of a 10wt%Fe2O3-MgAl2O4 spinel were investigated using XRD and time resolved Fe-K QXANES. The Rietveld refinement of the XRD pattern showed the replacement of Al with Fe in the spinel structure and the formation of MgFeAlOx. The XANES pre-edge feature was employed to study the reduction kinetics during H2-TPR (Temperature Programmed Reduction) up to 730°C. About 55% of the Fe3+ in MgFeAlOx was reduced to Fe2+. A shrinking core model, which takes into account both solid-state diffusion via an oxygen diffusion coefficient, and gas-solid reaction through a reaction rate coefficient, was applied. The activation energy for chemical reaction showed a linear dependence on the conversion, increasing from 104 kJ/mol to 126 kJ/mol over the course of material reduction. The good accordance between the shrinking core model description and the experimental data indicates that XANES pre-edge features can be used to correlate changes in material structure and reaction kinetics. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-27T10:35:26.233322-05:
      DOI: 10.1002/aic.16017
       
  • Effect of Viscosity on Liquid Curtain Stability
    • Authors: Alireza Mohammad Karim; Wieslaw J. Suszynski, Lorraine F. Francis, Marcio S. Carvalho
      Abstract: The effect of viscosity on liquid curtain stability was explored by high-speed visualization. Measurements of the velocity within the curtain revealed the presence of a viscous boundary layer along the edge guides. The critical condition at the onset of curtain breakup was determined by identifying the flow rate below which the curtain broke for two different edge guide geometries: parallel and convergent. Curtain breakup was initiated by the expansion of a hole within the curtain. For low viscosity liquid, the measured hole retraction speed is independent of the viscosity and equal to the Taylor-Culick speed. For high viscosity liquids, the retraction speed is lower than the Taylor-Culick speed due to viscous forces that resist the flow. The results also show the effect of liquid viscosity on the curtain stability is a strong function of the edge guide design. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-24T11:06:24.441319-05:
      DOI: 10.1002/aic.16015
       
  • 3D-Foam-Structured Nitrogen-Doped Graphene-Ni Catalyst for Highly
           Efficient Nitrobenzene Reduction
    • Authors: Zhiyong Wang; Yuan Pu, Dan Wang, Jie Shi, Jie-Xin Wang, Jian-Feng Chen
      Abstract: We report the preparation of a porous 3D-foam-structured nitrogen-doped graphene-Ni (NG/NF) catalyst and the evaluation of its performance in the reduction of nitrobenzene (NB) through detailed studies of the kinetics. The NG/NF catalyst showed a significantly higher reaction rate than pure Ni foam (NF). Moreover, the separation of the 3D-foam-structured catalyst from the products was more convenient than that of NG powdered catalysts. The obtained kinetics data fit well to the Langmuir-Hinshelwood model, with an error ratio below 10%. Density functional theory (DFT) calculations indicated that the adsorption of sodium borohydride (NaBH4) on the NG/NF surface was stronger than that of NB, which strongly agreed with the kinetic parameters determined from the Langmuir-Hinshelwood model. The excellent catalytic efficiency of the 3D-foam-structured catalyst combined with the knowledge of the kinetics data make this catalyst promising for application in larger scale nitrobenzene reduction. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-24T11:05:10.257711-05:
      DOI: 10.1002/aic.16016
       
  • Highly Efficient Separation of Strongly Hydrophilic Structurally-Related
           Compounds by Hydrophobic Ionic Solutions
    • Authors: Qiwei Yang; Shaocong Guo, Xianxian Liu, Zhiguo Zhang, Zongbi Bao, Huabin Xing, Qilong Ren
      Abstract: The selective separation of strongly hydrophilic structurally-related compounds in aqueous solutions is a long-standing challenge due to a trade-off between separation selectivity and capacity. This work shows a new method to separate strongly hydrophilic structurally-related compounds through hydrophobic ionic solution-based liquid-liquid extraction, with L-ascorbic acid 2-glucoside (AA-2G) and L-ascorbic acid as model compounds. Extraordinary distribution coefficient, superb molecular selectivity, large extraction capacity and good recyclability without using strong acids and salts were all achieved, with a small consumption of phosphonium bromide ionic liquid and aprotic molecular diluent. The essence of this method is the successful combination of both strong hydrogen-bond basicity and good hydrophobicity along with significant preferential solvation phenomena of the constructed ionic solutions. Even if at a high feed concentration of 100 mg/ml, the purity of AA-2G could be greatly elevated from 50% to 96.2% with an ultrahigh yield of almost 100% after five-stage countercurrent extraction. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-22T05:55:31.803455-05:
      DOI: 10.1002/aic.16013
       
  • Joint Capacity Planning and Distribution Network Optimization of Coal
           Supply Chains under Uncertainty
    • Authors: Rui-Jie Zhou; Li-Juan Li
      Abstract: A two-stage stochastic integer programming model is developed to address the joint capacity planning and distribution network optimization of multi-echelon coal supply chains (CSCs) under uncertainty. The proposed model not only introduces the uses of compound real options in sequential capacity planning, but also considers uncertainty induced by both risks and ambiguities. Both strategic decisions (i.e., facility locations and initial investment, service assignment across the entire CSC, and option holding status) and scenario-based operational decisions (i.e., facility operations and capacity expansions, outsourcing policy, and transportation and inventory strategies) can be simultaneously determined using the model. By exploiting the nested decomposable structure of the model, we develop a new distributed parallel optimization algorithm based on non-convex generalized Bender decomposition and Lagrangean relaxation to mitigate the computation resource limitation. One of the main CSCs in China is studied to demonstrate the applicability of the proposed model and the performance of the algorithm. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-22T05:55:25.758985-05:
      DOI: 10.1002/aic.16012
       
  • Enhancing CO2 Absorption Efficiency using a Novel PTFE Hollow Fiber
           Membrane Contactor at Elevated Pressure
    • Authors: Fushan Wang; Guodong Kang, Dandan Liu, Meng Li, Yiming Cao
      Abstract: The internal structure design of membrane module is very important for gas removal performance using membrane contactor via physical absorption. In this study, a novel membrane contactor developed by weaving polytetrafluoroethylene (PTFE) hollow fibers was applied to remove CO2 from 60% N2 + 40% CO2 mixture (with CO2 concentration similar to that of biogas) at elevated pressure (0.8 MPa) using water as absorbent. Compared with the conventional module with randomly packed straight fibers, the module with woven PTFE fibers exhibited much better CO2 absorption performance. The weaving configuration facilitated the meandering flow or Dean vortices and renewing speed of water around hollow fibers. Meanwhile, the undesired influences such as channeling and bypassing were also eliminated. Consequently, the mass transfer of liquid phase was greatly improved and the CO2 removal efficiency was significantly enhanced. The effects of operation pressure, module arrangement, feed gas and water flow rate on CO2 removal were systematically investigated as well. The overall mass transfer coefficient (KOV) varied from 1.96 × 10−5 to 4.39 × 10−5 m/s (the volumetric mass transfer coefficient KLa = 0.034 – 0.075 s−1) under the experimental conditions. The CO2 removal performance of novel woven fiber membrane contactor matched well with the simulation results. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-22T05:50:24.492818-05:
      DOI: 10.1002/aic.16014
       
  • Two-Step Continuous Production of Monodisperse Colloidal Ellipsoids at
           Rates of One Gram per Day
    • Authors: Joseph A. Ferrar; Leonid Pavlovsky, Yanliang Liu, Eric Viges, Michael J. Solomon
      Abstract: We report a two-step process for the continuous production of monodisperse polystyrene colloidal ellipsoids of aspect ratios up to 6.8 at rates that exceed 1.0 g per day, an improvement upon previously reported synthetic batch processing rates of nearly a factor of 20. This scale up is accomplished by continuous evaporative processing of a polymer solution into an elastomeric film embedded with colloidal spheres. Subsequently, the film is continuously elongated at a temperature that stretches the embedded spheres into ellipsoids. The method is used to deform initially 1.0 μm diameter spheres into ellipsoids of aspect ratio 1.27 ± 0.15, 3.31 ± 0.44, 3.91 ± 0.72, 4.14 ± 0.47, and 6.77 ± 1.01. The particle production rate reported here opens new possibilities for applications of monodisperse ellipsoids, such as self-assembly and optical characterization of complex crystalline unit cells, as well as rheological characterization of dilute gels and dense suspensions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-19T11:06:30.057101-05:
      DOI: 10.1002/aic.16009
       
  • Liquid-Liquid Two-Phase Flow in Ultrasonic Microreactors: Cavitation,
           Emulsification and Mass Transfer Enhancement
    • Authors: Shuainan Zhao; Zhengya Dong, Chaoqun Yao, Zhenghui Wen, Guangwen Chen, Quan Yuan
      Abstract: The effects of ultrasound on the hydrodynamic and mass transfer behaviors of immiscible liquid-liquid two-phase flow were investigated in a domestic ultrasonic microreactor. Under ultrasonic irradiation, cavitation bubble was generated and underwent violent oscillation. Emulsification of immiscible phases was initiated by virtue of oscillating bubbles shuttling through the water/oil interface. The pressure drop was found to decrease with increasing ultrasound power, with a maximum decrement ratio of 12% obtained at power 30 W. The mass transfer behavior was characterized by extraction of Rhodamine B from water to 1-octanol. An enhancement factor of 1.3-2.2 on the overall mass transfer coefficient was achieved under sonication. The mass transfer performance was comparable to passive microreactor at similar energy dissipation rate (61-184 W/kg). The extraction equilibrium was reached under a total flow velocity 0.01 m/s and input power 20 W and 30 W, exhibiting its potential use in liquid-liquid extraction process. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-19T11:06:19.903927-05:
      DOI: 10.1002/aic.16010
       
  • Multivariable Model Predictive Control of a Novel Rapid Pressure Swing
           Adsorption System
    • Authors: Matthew D. Urich; Vemula Rama Rao, Mayuresh V. Kothare
      Abstract: A multivariable model predictive control (MPC) algorithm is developed for the control and operation of a rapid pressure swing adsorption (RPSA) based medical oxygen concentrator (MOC). The novelty of the approach is the use of all four step durations in the RPSA cycle as independent manipulated variables in a truly multivariable context. The RPSA has a complex, cyclic, nonlinear multivariable operation that requires feedback control, and MPC provides a suitable framework for controlling such a multivariable system. The multivariable MPC presented here uses a quadratic optimization program with integral action and a linear model identified using sub-space system identification techniques. The controller was designed and tested in simulation using a complex, highly coupled, nonlinear RPSA process model. The model was developed with the least restrictive assumptions compared to those reported in the literature, thereby providing a more realistic representation of the underlying physical phenomena. The resulting MPC effectively tracks set points, rejects realistic process disturbances and is shown to outperform conventional PID control. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-19T11:05:22.900109-05:
      DOI: 10.1002/aic.16011
       
  • Receding horizon optimal operation and control of a solar-thermal district
           heating system
    • Authors: Xiaodong Xu; Yuan Yuan, Stevan Dubljevic
      Abstract: This work focuses on the receding horizon optimal control for a solar-thermal district heating (STDH) system containing lumped parameter and distributed parameter subsystems. A common STDH system includes solar collector system, a short term energy storage tank and a district heating loop system with a secondary gas boiler system. The inclusion or exclusion of these components leads to different operational and working modes. Detailed system description and mathematical models are provided, and three working modes are introduced and in each mode several operations are demonstrated and addressed. Single-objective and multi-objective problems are formulated. Moreover, in the mode where gas boiler system is included to help addressing the district heating demand, the internal model based boundary servo-control approach is proposed and applied to obtain desired boiler water temperatures such that the expected district heating demand can be satisfied. Moreover, a boundary state observer is designed for the considered solar collector system. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-19T11:00:23.030221-05:
      DOI: 10.1002/aic.16007
       
  • Simulation on Hydrogen Storage Properties of Metal-Organic Frameworks
           Cu-BTC at 77K∼298K
    • Authors: Shumin Chen; Yumei Shi, Bo Gu
      Abstract: In recent years, many researchers have studied on the hydrogen storage properties of metal-organic frameworks (MOFs) by grand canonical Monte Carlo (GCMC) simulation. At present, the GCMC studies of Cu-BTC (BTC: benzene-1,3,5-tricarboxylate) which is a prototypical metal-organic framework mainly adopt the classical force fields, the simulation temperatures are mainly focus on 298K and 77K, and most researchers didn't consider the effects of quantum effects at low temperature. Therefore, we used the quantum effects to correct the classical force fields and the force fields with more accurate simulation results were used to simulate the hydrogen adsorption performances of Cu-BTC in the temperature range of 77K∼298K and the pressure range of 1∼8MPa at each temperature. The results show that the effects of quantum effects on the hydrogen storage of Cu-BTC cannot be neglected and the corrected Dreiding force field can simulate hydrogen adsorption performances of Cu-BTC more accurately at low temperature. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-19T11:00:19.409574-05:
      DOI: 10.1002/aic.16008
       
  • Low Reynolds number isotope transient kinetic modeling in isothermal
           differential tubular catalytic reactors
    • Authors: Masood Otarod; Ronald M. Supkowski
      Abstract: A novel method is presented for modeling steady state isotope transient kinetics of heterogeneous catalytic reactions when the flow regime is laminar and conversion is differential. It is based on a factorization theorem which is deduced from the observation that transport functions fluctuate radially in porous beds. Factorization separates the radial from axial and temporal coordinates of the flow rate and concentration functions. It is shown that in transient tracing with a differential conversion, the radial components of the transport functions in the material conservation equations can be integrated into constant parameters to be determined from experimental data. The method is in particular useful since the knowledge of the radial profile of velocity and other transport functions and parameters are not prerequisites for data correlation. The methodology was successfully applied to the adsorption of carbon monoxide in Boudouard reaction on an alumina supported palladium catalyst. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-16T01:15:28.033637-05:
      DOI: 10.1002/aic.16006
       
  • A Pore Network Study of Evaporation from the Surface of a Drying
           Non-Hygroscopic Porous Medium
    • Authors: Alireza Attari Moghaddam; Abdolreza Kharaghani, Evangelos Tsotsas, Marc Prat
      Abstract: The phenomena occurring at the surface of a porous medium during drying in the capillary regime are investigated by pore network simulations. The impact of the formation of wet and dry patches at the surface on the drying rate is studied. The simulations indicate an edge effect characterized by a noticeable variation of saturation in a thin layer adjacent to the porous surface. Also, the results indicate a significant non-local equilibrium effect at the surface. The simulation results are exploited to test Schlünder's classical model which offers a simple closure relationship between the evaporation rate and the degree of occupancy of the surface by the liquid. In addition to new insights into the surface phenomena, the results open up new prospects for improving the continuum models of the drying process. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-13T10:55:37.309147-05:
      DOI: 10.1002/aic.16004
       
  • DEM-PBM modeling of abrasion dominated ribbon breakage
    • Authors: Simone Loreti; Chuan-Yu Wu, Gavin Reynolds, Jonathan Seville
      Abstract: In dry granulation, fine cohesive powders are compacted into large multi-particle entities, i.e., briquettes, flakes or ribbons. The powder compaction is generally followed by milling, a size reduction process, which is crucial to obtain the desired granule size or properties. Abrasion and impact are two primary mechanisms of comminution in ribbon milling, but they are not completely understood. The aim of this paper was hence to investigate numerically the fragmentation process induced by abrasion during ribbon milling. The discrete element method (DEM) was employed to simulate abrasion tests, for which three-dimensional parallelepiped ribbons were generated using auto-adhesive elastic spheres. The fragmentation rate, and the fragments size and number were determined for various surface energies and abrasive velocities. The DEM results showed that the mass-equivalent fragment size distributions were bi-modal, similar to the experimental observations and the numerical results for impact-dominated ribbon milling reported in the literature. In addition, two quantities were determined from the DEM analysis, i.e. the number of large fragments and the fraction of fines, which was then integrated into the population balance models (PBM) so that a DEM-PBM multiscale modeling framework was developed to predict the granule size distribution during ribbon milling. The DEM-PBM results were compared with the experimental results reported in the literature, and a broad agreement was obtained, implying the proposed DEM-PBM can be used to analyse the ribbon milling behavior. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-13T10:55:31.869796-05:
      DOI: 10.1002/aic.16005
       
  • Improving mixing characteristics with a pitched tip in kneading elements
           in twin-screw extrusion
    • Authors: Yasuya Nakayama; Hiroki Takemitsu, Toshihisa Kajiwara, Koichi Kimura, Takahide Takeuchi, Hideki Tomiyama
      Abstract: In twin-screw extrusion, the geometry of a mixing element mainly determines the basic ow pattern, which eventually affects the mixing ability as well as the dispersive ability of the mixing element. We discuss the effects of geometrical modification, with both forward and backward pitched tips, of a conventional forwarding kneading discs element (FKD) in the pitched-tip kneading discs element (ptKD) on the ow pattern and mixing characteristics. Numerical simulations of fully-filled, non-isothermal polymer melt ow in the melt-mixing zone were performed, and the flow pattern structure and the tracer trajectories were investigated. The pitched tips largely affects the inter-disc fluid transport, which is mainly responsible for mixing. These changes in the local ow pattern are analyzed by the distribution of the strain-rate state. The distribution of the finite-time Lyapunov exponent reveals a large inhomogeneity of the mixing in FKD is suppressed both by the forward and backward tips. By the forward tips on FKD, the mixing ability is relatively suppressed compared to FKD, whereas for the backward tips on FKD, the mixing ability is enhanced while maintaining the same level of dispersion efficiency as FKD. From these results, the pitched tips on the conventional KD turns out to be effective at reducing the inhomogeneity of the mixing and tuning the overall mixing performance. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-13T10:46:06.039922-05:
      DOI: 10.1002/aic.16003
       
  • Chemical Hydrodynamics of a Downward Microbubble Flow for Intensification
           of Gas-Fed Bioreactors
    • Authors: Manizheh Ansari; D.E. Turney, R. Yakobov, D.V. Kalaga, S. Kleinbart, Sanjoy Banerjee, J.B. Joshi
      Abstract: Bioreactors are of interest for value-upgrading of stranded or waste industrial gases. Reactor intensification requires development of low cost bioreactors with fast gas-liquid mass transfer rate. Here we assess published reactor technology in comparison with a novel downward bubble flow created by a micro-jet array. Compared to known technology, the advanced design achieves higher volumetric gas transfer efficiency (kLa per power density) while operating at higher kLa. We measure the effect of four reactor heights (height-to-diameter ratios of 12, 9, 6 and 3) on the gas transfer coefficient kL, total interfacial area a, liquid residence time distribution, energy consumption, and turbulent hydrodynamics. Leading models for predicting kL and a are appraised with experimental data. The results show kL is governed by “entrance effects” due to Higbie penetration dominate at short distances below the micro-jet array, while turbulence dominates at intermediate distances, and finally terminal rise velocity dominates at large distances. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-13T10:45:25.454122-05:
      DOI: 10.1002/aic.16002
       
  • Pressure Drop through Platinized Titanium Porous Electrodes for
           Cerium-based Redox Flow Batteries
    • Authors: Luis F. Arenas; Carlos Ponce de León, Frank C. Walsh
      Abstract: The pressure drop, ΔP, across a redox flow battery is linked to pumping costs and energy efficiency, making fluid properties of electrodes important in scale-up. In this work, the ΔP at diverse platinized titanium electrodes in Ce-based redox flow batteries is reported as a function of mean linear electrolyte velocity measured in a rectangular channel flow cell. Darcy's friction factor and permeability vs. Reynolds number are calculated. Average permeability values are: 7.10 × 10−4 cm2 for Pt/Ti mesh, 4.45 × 10−4 cm2 for Pt/Ti plate + turbulence promoters, 1.67 × 10−5 cm2 for Pt/Ti micromesh, and 1.31 × 10−6 cm2 for Pt/Ti felt. The electrochemical volumetric mass transport coefficient, kmAe, is provided as a function of ΔP. In the flow-by configuration, Pt/Ti felt combines high kmAe values with a relatively high ΔP, followed by Pt/Ti micromesh. Pt/Ti mesh and Pt/Ti plate gave a lower ΔP but poorer electrochemical performance. Implications for cell design are discussed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-12T11:30:36.188909-05:
      DOI: 10.1002/aic.16000
       
  • Modeling the Deposition of Fluorescent Whitening Agents (FWAs) on Cotton
           Fabrics
    • Authors: L. Bueno; C. Amador, S. Bakalis
      Abstract: The adsorption of two widely used Fluorescent Whitening Agents (FWAs) on un-brightened cotton fabrics has been investigated as a function of temperature, hardness of the wash liquor, initial concentration of FWA in solution and fabric to wash liquor ratio. Sorption efficiencies of FWAs have been studied using a UV spectrophotometry technique. A mechanistic model has been developed to describe the dissolution process of FWAs, convective mass transport into the fabrics, diffusion in the stagnant layer to the fabrics' surface and adsorption of FWAs on cotton fabrics. Dual porosity of the fabrics (inter-yarn and intra-yarn porosity) has been considered by allowing two different regions (outer and inner areas of the cotton fabrics) where FWAs molecules can diffusive and adsorb. Good agreement between experimental and predicted whiteness benefit by the proposed mathematical model has been observed for the range of variables considered. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-12T11:15:27.922426-05:
      DOI: 10.1002/aic.16001
       
  • Computer-Aided Design of Ionic Liquids as Solvents for Extractive
           Desulfurization
    • Authors: Zhen Song; Chenyue Zhang, Zhiwen Qi, Teng Zhou, Kai Sundmacher
      Abstract: Although ionic liquids (ILs) have been widely explored as solvents for extractive desulfurization (EDS) of fuel oils, systematic studying of the optimal design of ILs for this process is still scarce. In this work, the UNIFAC-IL model is extended first to describe the EDS system based on exhaustive experimental data. Then, based on the obtained UNIFAC-IL model and group contribution models for predicting the melting point and viscosity of ILs, a mixed-integer nonlinear programming (MINLP) problem is formulated for the purpose of computer-aided ionic liquid design (CAILD). The MINLP problem is solved to optimize the liquid-liquid extraction performance of ILs in a given multi-component model EDS system, under consideration of constraints regarding the IL structure, thermodynamic and physical properties. The top five IL candidates pre-identified from CAILD are further evaluated by means of process simulation using ASPEN Plus. Thereby, [C5MPy][C(CN)3] is identified as the most suitable solvent for extractive desulfurization. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-10T18:40:34.375093-05:
      DOI: 10.1002/aic.15994
       
  • Synergistic Effects of Sulfur Poisoning and Gas Diffusion on Polarization
           Loss in Anodes of Solid Oxide Fuel Cells
    • Authors: Yinghua Niu; Weiqiang Lv, Zhaohuan Wei, Weirong Huo, Weidong He
      Abstract: Poisoning effects of sulfur compounds on the performances of solid oxide fuel cells (SOFCs) are non-trivial. However, the synergistic effects of gas diffusion, adsorption, desorption and reaction in anodes are typically neglected. In this work, an analytical model is derived to quantitatively evaluate the poisoning effects of H2S. The results show that sulfur poisoning correlates closely with inefficient gas diffusion for small anode pore size, small porosity/tortuosity and low working temperatures. As compared with concentration polarization, H2S-diffusion-induced activation polarization in thin anodes with a large ε/τ is detrimental, especially for low-temperature operations with a high H2S concentration and a low current density. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-10T18:40:31.827109-05:
      DOI: 10.1002/aic.15997
       
  • The Promotion of Argon and Water Molecule on Direct Synthesis of H2O2 from
           H2 and O2
    • Authors: Yanhui Yi; Li Wang, Juan Yu, Changgong Meng, Jialiang Zhang, Hongchen Guo
      Abstract: Direct synthesis of hydrogen peroxide (H2O2) from H2 and O2 is an ideal route. H2/O2 plasma has a great potential for direct synthesis of high purity H2O2 without purification operations. However, low yield and high energy consumption limits the application of H2/O2 plasma in industry. This paper reports that gas state Ar and H2O molecule serving as molecular catalysts promoted the synthesis of H2O2 from H2/O2/Ar/H2O plasma dramatically: the H2O2 yield was enhanced by 244% and the energy consumption was reduced by 70.9%. Ar not only increased the electron density, but also selectively accelerated the dissociation of H2 towards the formation of •HO2, a key intermediate species in H2O2 synthesis. While H2O facilitated the formation of •HO2 radical and stabilized it by forming a HO2•H2O complex, resulting in enhancing the H2O2 production. This single molecular catalysis reduced the cost of H2O2 synthesis more than 50%. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-10T18:40:28.540728-05:
      DOI: 10.1002/aic.15999
       
  • Integrated Solvent and Process Design for Continuous Crystallization and
           Solvent Recycling using PC-SAFT
    • Authors: Jiayuan Wang; Richard Lakerveld
      Abstract: Solvent usage is a major source of environmental waste in pharmaceutical industry. The current paradigm shift towards continuous manufacturing in pharmaceutical industry has renewed the interest in continuous crystallization, which offers the prospect of easy solvent recycling. However, the selection of solvents for an integrated crystallization processes is nontrivial due to the likely trade-off between optimal solvent properties for crystallization and solvent separation and recycling. A systematic approach for the simultaneous optimization of process conditions and solvent selection for continuous crystallization including solvent recycling is presented. A unified PC-SAFT model framework is applied to predict thermodynamic properties related to solubility and vapor-liquid equilibrium, which is integrated with a process model. A continuous mapping procedure is adopted to solve the optimization problem effectively. A case study based on continuous anti-solvent crystallization of paracetamol with solvent separation via flash demonstrates the approach. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-10T18:40:21.501415-05:
      DOI: 10.1002/aic.15998
       
  • A Tribute to Roy Jackson
    • Authors: Sankaran Sundaresan; Christine M. Hrenya, Michael P. Harold, Jennifer Sinclair Curtis
      PubDate: 2017-10-10T18:35:26.503596-05:
      DOI: 10.1002/aic.15993
       
  • A Dynamic Game Theoretic Framework for Process Plant Competitive Upgrade
           and Production Planning
    • Authors: Philip Tominac; Vladimir Mahalec
      Abstract: A dynamic potential game theoretic production planning framework is presented in which production plants are treated as individual competing entities and competition occurs dynamically over a discrete finite time horizon. A modified Cournot oligopoly with sticky prices provides the basis for dynamic game theoretic competition in a multi-market nonlinear and nonconvex production planning model wherein market price adapts to a value that clears cumulative market supply. The framework is used to investigate a petrochemical refining scenario in which a single inefficient refiner faces elimination by its competitors; we demonstrate that there exist conditions under which the threatened refiner may upgrade itself in order to become competitive and escape the threat, or alternatively in which the threat of elimination will never be carried out and the refiner is effectively safe in the given market configuration. Globally optimal dynamic Nash equilibrium production trajectories are presented for each case. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-10T18:35:24.932878-05:
      DOI: 10.1002/aic.15995
       
  • A Thermodynamic Investigation of Adsorbate-Adsorbate Interactions of
           Carbon Dioxide on Nanostructured Carbons
    • Authors: Maxwell Murialdo; Channing C. Ahn, Brent Fultz
      Abstract: A thermodynamic study of carbon dioxide adsorption on a zeolite-templated carbon (ZTC), a superactivated carbon (MSC-30) and an activated carbon (CNS-201) was carried out at temperatures from 241 to 478 K and pressures up to 5.5•106 Pa. Excess adsorption isotherms were fitted with generalized Langmuir-type equations, allowing the isosteric heats of adsorption and adsorbed-phase heat capacities to be obtained as a function of absolute adsorption. On MSC-30, a superactivated carbon, the isosteric heat of carbon dioxide adsorption increases with occupancy from 19 to 21 kJ•mol−1, before decreasing at high loading. This increase is attributed to attractive adsorbate-adsorbate intermolecular interactions as evidenced by the slope and magnitude of the increase in isosteric heat and the adsorbed-phase heat capacities. An analysis of carbon dioxide adsorption on ZTC indicates a high degree of binding-site homogeneity. A generalized Law of Corresponding States analysis indicates lower carbon dioxide adsorption than expected. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-10T18:35:22.8165-05:00
      DOI: 10.1002/aic.15996
       
  • An interfacial curvature distribution model and phase inversion
    • Authors: A. Vikhansky
      Abstract: The state of the two-phase system is described by the interfacial curvature distribution. A phenomenological closure model is proposed for the exact (unclosed) equations. Parameters of the model are related to the existing correlations for drop size in stirred flows. If water is dispersed in oil, the curvature has a uni-modal distribution with a positive mode. When a control parameter, e.g., water volume fraction is increasing, the distribution becomes bi-modal with both negative and positive values. After a while, the phase inversion occurs, and the distribution becomes uni-modal with a negative mode. Going in the other direction the phase inversion happens at lower volume fraction of water, i.e., there is an ambivalent region, where both phases might be in the dispersed state. The model implies, that even if the conditions for phase inversion are met, there might be a significant delay before the new morphology is established. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-06T17:50:21.172204-05:
      DOI: 10.1002/aic.15992
       
  • The lift on a disc immersed in a rotating granular bed
    • Authors: Bhanjan Debnath; K. Kesava Rao, Prabhu R. Nott
      Abstract: The discrete element method has been used to study the lift FL on a stationary disc immersed coaxially in a slowly rotating cylinder containing a granular material. In a tall granular column, FL rises with the immersion depth h, but reaches a roughly constant asymptote at large h, in agreement with previous studies. Our results indicate that the argument in some earlier studies that FL is proportional to the static stress gradient is incorrect. Instead, our results show that the lift is caused by an asymmetry in the dilation and shear rate between the regions above and below the disc. We argue that the cause of the lift is similar to that in fluids, namely that it arises as a result of the disturbance in the velocity and density fields around the body due to its motion relative to the granular bed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-05T06:55:24.428784-05:
      DOI: 10.1002/aic.15991
       
  • Model Based Analysis of Lithium Batteries Considering Particle Size
           Distribution
    • Authors: E. R. Henquín; P. A. Aguirre
      Abstract: Performance of lithium ion batteries whose electrodes are composed of particles of different sizes is studied. Simplified model developed in 7 is extended and the simulations are compared with experiments from the literature so as to validate this new model. The differences in current density observed in particles of different sizes, which are in contact, depend on particle size and state of charge. Internal particle to particle discharge currents are observed during relaxation times. A parametric study of the applied current and particle sizes of electrodes is carried out to evaluate cell performance, with emphasis on cell voltage and final capacity measurement. The evolution of reaction rates on the surface of electrode particles and their corresponding states of charge are depicted. An analysis of relaxation times in terms of cell voltage, current density, equilibrium potentials, and overpotentials is included. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-05T04:20:21.195117-05:
      DOI: 10.1002/aic.15990
       
  • Packaging of Yield Stress Fluids: Flow Patterns
    • Authors: Fanny Rasschaert; Emeline Talansier, Didier Blésès, Maud Lambert, Albert Magnin
      Abstract: The packaging or filling of a container with a non-Newtonian fluid without quality failures is a current issue encountered at the final step of industrial product processes. In this work, the container filling of viscoplastic fluids is studied by using an experimental laboratory plant able to reproduce the industrial transitory packaging conditions. Firstly, a Newtonian validation was conducted in order to compare and to confirm our set-up results with available literature data. Secondly five flow patterns including dripping, jet buckling, mounding, planar filling and air entrainment were observed and characterized for the viscoplastic container filling. Most of them present different types of instabilities during the filling, except the planar filling, which seems to be ideal according to industrial specifications. A flow pattern distribution depending on relevant dimensionless numbers was developed. Finally, flow pattern transition criteria are determined highlighting the influence of rheological and process parameters on container filling. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-04T10:56:05.754901-05:
      DOI: 10.1002/aic.15989
       
  • Enhanced Solubility of Hydrogen and Carbon Monoxide in Propane- and
           Propylene-Expanded Liquids
    • Authors: Dupeng Liu; Raghunath V. Chaudhari, Bala Subramaniam
      Abstract: Conventional propylene hydroformylation occurs in a gas-expanded liquid phase. Reliable knowledge of the phase equilibria of such systems, including the solubilities of CO and H2 in propylene-expanded solvents, is essential for rational process design and development. Herein, we report the vapor-liquid equilibrium (VLE) data of the following ternary systems involving CO, H2, propane, propylene, toluene and NX-795 at temperatures from 70 to 90°C and pressures up to 1.5 MPa: propane/H2/toluene, propane/CO/toluene, propylene/H2/toluene, propylene/CO/toluene, propane/H2/NX-795, propane/CO/NX-795, propylene/H2/NX-795 and propylene/CO/NX-795. The solubilities of H2 and CO in either propane-expanded or propylene-expanded phases are observed to be greater than those in the neat organic solvents, by as high as 66% at 70°C and 1.5 MPa. By modeling the vapor and the liquid phases as pseudo-binary systems, the Peng-Robinson equation of state (PR-EoS) with van der Waals' mixing rules and binary interaction parameters is shown to satisfactorily predict the experimental VLE data. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-04T10:25:33.770979-05:
      DOI: 10.1002/aic.15988
       
  • A Pseudo-Transient Optimization Framework for Periodic Processes: Pressure
           Swing Adsorption and Simulated Moving Bed Chr
    • Authors: Calvin Tsay; Richard C. Pattison, Michael Baldea
      Abstract: Πeriodic systems are widely used in separation processes and in reaction engineering. They are designed for and operated at a cyclic steady state (CSS). Identifying and optimizing the CSS has proven to be computationally challenging. In this paper, we introduce a novel framework for equation-oriented simulation and optimization of cyclic processes. We propose a two-step reformulation of the process model, comprising, i) a full discretization of the time and spatial domains and ii) re-casting the discretized model as a differential-algebraic equation (DAE) system, for which we provide theoretical stability guarantees. Additionally, we establish a mathematical, structural connection between the CSS constraints and material recycling, which allows us to deal with these conditions via a “tearing” procedure. We integrate these developments in a pseudo-transient design optimization framework and present two extensive case studies: a simulated moving bed chromatography system and a pressure swing adsorption process. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-03T10:25:30.192562-05:
      DOI: 10.1002/aic.15987
       
  • Mixing Processes in the Cavity Transfer Mixer: a Thorough Study
    • Authors: Giovanna Grosso; Martien A. Hulsen, Arash Sarhangi Fard, Andrew Overend, Patrick D. Anderson
      Abstract: In many industrial applications, the quality of mixing between different materials is fundamental to guarantee the desired properties of products. However, properly modelling and understanding polymer mixing presents noticeable difficulties, because of the variety and complexity of the phenomena involved. This is also the case with the Cavity Transfer Mixer (CTM), an add-on to be mounted downstream of existing extruders, in order to improve distributive mixing. The present work proposes a fully three-dimensional model of the CTM: a finite element solver provides the transient velocity field, which is used in the mapping method implementation in order to compute the concentration field evolution and quantify mixing. Several simulations are run assessing the impact on mixing of geometrical and functioning parameters. In general, the number of cavities per row should be limited and the cavity size rather big in order to guarantee good mixing quality. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-29T11:44:51.410537-05:
      DOI: 10.1002/aic.15986
       
  • Detailed Thermodynamics for Analysis and Design of Ranque-Hilsch Vortex
           Tubes
    • Authors: John P. O'Connell
      Abstract: The Ranque-Hilsch vortex tube is a device for continuously separating an inlet pressurized fluid stream into two outlet streams of warmer and cooler temperatures at lower pressures, with no moving parts and without any heat or work effects. It has been applied to cool or heat small systems where refrigeration is impractical. Studies of the fluid mechanics inside the tube have not fully established the flow structure that provides the separation. Thermodynamic energy and entropy balances giving relations among properties and the relative amounts of the three fluid streams have been examined to determine consistency among measured data along with sensitivity of the phenomena to tube configuration, measurement error, and properties. The strong response of the temperature separation to small variations in entropy generation is shown to limit the possibilities for generalized prediction of vortex tube behavior. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-29T11:44:15.594323-05:
      DOI: 10.1002/aic.15985
       
  • Understanding Interfacial Behaviors of Isobutane Alkylation with C4 Olefin
           Catalyzed by Sulfuric Acid or Ionic Liquids
    • Authors: Weizhong Zheng; Huanying Wang, Wenxiu Xie, Ling Zhao, Weizhen Sun
      Abstract: The interfacial properties between the hydrocarbon phase including isobutane and 2-butene and the catalyst phase including H2SO4 or ionic liquids (ILs) with various alkyl chain length on their imidazolium cations have been investigated using molecular dynamics (MD) simulations. Compared to H2SO4, ILs could obviously improve the interfacial width, solubility and diffusion of reactants at the interface. The ILs with longer chains on cations exhibit a significant density enrichment of alkyl chains at the interface and tend to orient themselves with alkyl chains perpendicular to the interface and protruding into the reactants phase, which is in good agreement with the van der Waals energy between the reactants and cations of the ILs. The longer chains on cations could promote the interfacial width and facilitate the dissolution of isobutane in catalyst phase, and thus exhibits a better catalytic performance, which agrees well with alkylation experiments in this work. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-29T11:44:10.083427-05:
      DOI: 10.1002/aic.15984
       
  • Multiple Order Model Migration and Optimal Model Selection for Online
           Glucose Prediction in Type 1 Diabetes
    • Authors: Hong Zhao; Chunhui Zhao, Chengxia Yu, Eyal Dassau
      Abstract: In order to address the problem of insufficient available modelling data for glucose prediction, as well as modelling burden, a model migration method was developed in a previous work to quickly transfer an old model to a new subject by using a simple parameter adjustment. However, this method, which is referred to as first order model migration (FOMM), only considers a single order for each exogenous input, and may not produce an optimal model structure for accurate prediction. To overcome this problem, a multiple order model migration (MOMM) algorithm is proposed in this study. For different numbers of modelling samples, including glucose and two exogenous inputs (meal and insulin), the optimal modelling method may be different, and therefore must be properly determined for each modelling scenario. First, the optimal model order is determined for each input and a multiple order prediction model is used. Then, a MOMM algorithm is developed based on particle swarm optimization (PSO) to simultaneously revise multiple parameters. The multiple order parameters of each input in the old model are quickly customized so that the revised model can be used for new subjects with desirable prediction accuracy. In particular, the influence of the number of modelling samples is analysed to check the applicability of different methods; this analysis determines the appropriate selection guidelines for the optimal model in response to different data sizes. The proposed method was evaluated using thirty in silico subjects and clinical data from seven individuals with type 1 diabetes mellitus (DM). Overall, the MOMM algorithm presented superior results when the time period for collecting the samples was larger than 10 h (50 samples). In particular, the size of the modelling samples was separated into three different regions by evaluating the glucose prediction performance and the comparison between different algorithms for both in silico and clinical subjects. In Region I, the FOMM method achieves the best performance. In Region II, the MOMM method should be used and the prediction accuracy is superior in Region II in general. With enough samples (Region III), the subject-dependent model (SM) algorithm can be chosen. The MOMM algorithm is demonstrated to be able to transfer models for new subjects with improved model structure. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-28T10:25:21.449536-05:
      DOI: 10.1002/aic.15983
       
  • A Tribute to Professor Roy Jackson: Intellectual Leader, Scholar, Mentor
    • Authors: Sankaran Sundaresan; Martin Feinberg, Kesava Rao Kaza, Prabhu R. Nott
      Abstract: This article, and this entire issue of the AIChE Journal, are meant to honor Professor Roy Jackson, whose contributions to chemical engineering have been profound and exceptionally broad. It is often said of Roy Jackson that few, if any, scholars have so deep a command of the full range of highly varied subjects that comprise the chemical engineering discipline. We have attempted a hardly-complete description of Professor Jackson's wide-ranging academic journey, both geographic (Cambridge, London, Edinburgh, Houston, Pasadena, Princeton) and intellectual (fluidization, mechanics of granular flows, process optimization, chemical reaction network theory, diffusion and reaction in porous catalyst pellets). The contributions of friends and colleagues appearing elsewhere in this issue are a testament to the broad range of subjects in which Professor Jackson had interest. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-26T11:15:36.321605-05:
      DOI: 10.1002/aic.15981
       
  • A Mesoscale Model for Diffusion and Permeation of Shale Gas at Geological
           Depth
    • Authors: Tiexin Tong; Dapeng Cao
      Abstract: The demand on energy is rising and shale gas as an important unconventional energy resource has received worldwide attention. It has shown a significant effect on the world's energy structure after the commercial exploitation of shale gas in the United States. Understanding diffusion and permeation of shale gas at geological depths is quite essential, but it cannot be described by traditional Fick or Knudsen diffusion models. In this work, we use dual control volume grand canonical molecular dynamics (DCV-GCMD) method to systematically investigate the permeation process of shale gas in montmorillonite (i.e. a clay mineral of shale) at different geological depths. Results indicate that temperature, pressure and pore size have an important effect on the permeability, and Knudsen equation cannot describe the permeability of shale gas. Accordingly, on the basis of these simulated data, we propose a new mesoscale model to describe the permeability of shale gas at geological depths. The new mesoscale model shows extensive applicability and can excellently reproduce the extrapolation testing data, and it satisfactorily bridges the gap between Knudsen diffusion and Fick diffusion, which provides important fundamentals for exploitation of shale gas. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-26T11:15:19.247051-05:
      DOI: 10.1002/aic.15982
       
  • Numerical Prediction of Dust Capture Efficiency of a Centrifugal Wet
           Scrubber
    • Authors: Hassan Ali; Floren Plaza, Anthony Mann
      Abstract: The gas, liquid and dust particle behaviour inside a centrifugal wet scrubber was simulated and a sub-model for predicting its collection efficiency was developed that also takes in account the reduction in collection efficiency due to droplet carryover.Centrifugal wet scrubbers are used in many industries and deliver a high scrubbing efficiency at relatively low capital and operational costs. However, they often experience problems such as droplet carryover at high gas flows and reduced collection efficiency at low gas flows. An improved understanding of flow processes inside the scrubbers is needed to develop a better scrubber design. An experimental test facility was setup for this purpose which also served to validate the CFD modelling results. Ideal operating parameters for maximum scrubbing efficiency and minimum droplet carryover were identified. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-26T11:10:33.477652-05:
      DOI: 10.1002/aic.15979
       
  • Catalytic Combustion of SOFC Stack Flue Gas over CuO and Mn2O3 Supported
           by La0.8Sr0.2Mn0.67Cu0.33O3 Perovskite
    • Authors: Jae Gi Sung; Taewook Kim, Han Kyu Jung, Hwan Kim, Jong Shik Chung
      Abstract: An efficient oxidation catalyst was developed to increase the combustion efficiency of unreacted CO, H2, and CH4 in flue gas of solid oxide fuel cell (SOFC) stack. Amorphous Cu-Mn oxide catalyst (CuMnLa/Alumina) showed high catalytic activity, but significant degradation occurred due to phase transition to spinel structure at high temperatures (T > 650°C). La0.8Sr0.2Mn0.67Cu0.33O3 perovskite (LSMC(p)) supported CuO or Mn2O3 exhibited improved thermal stability than CuMnLa/Alumina catalyst. Especially in case of 50Mn/LSMC(p), after the catalyst was exposed to 800°C for 24 h, T50 of CO, H2 and CH4 was achieved at 170, 230 and 600°C, respectively. This result is much lower than that of CuMnLa/Alumina, which was exposed to the same condition. The high combustion efficiency is due to retention of the Cu2+-Mn3+ redox couple, and supply of lattice oxygen from LSMC(p), especially at high temperature. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-26T11:10:29.600618-05:
      DOI: 10.1002/aic.15980
       
  • Iron-based Electrochemically Mediated Atom Transfer Radical Polymerization
           with Tunable Catalytic Activity
    • Authors: Jun-Kang Guo; Zhou Yin-Ning, Luo Zheng-Hong
      Abstract: An iron-based electrochemically mediated atom transfer radical polymerization (eATRP) system with tunable catalytic activity was developed by adjusting the supporting electrolyte formula. Kinetic behaviors of the systems using four typical supporting electrolytes (namely, TBABr, TBAPF6, TBACl and TBABF4) were investigated. The type of anions was found to significantly affect the polymerization kinetics. TBAPF6 system proceeded with a considerable polymerization rate, whereas TBABr system showed better controllability. Importantly, the effect of supporting electrolyte on eATRP kinetics (mainly on ATRP equilibrium) was confirmed through kinetic modeling. Furthermore, the effect of catalyst loading using TBAPF6 as supporting electrolyte was also studied, and the results showed an uncontrolled polymerization for catalyst loading lower than 500 ppm. When hybrid supporting electrolyte (TBAPF6/TBABr) was used to tune catalytic activity, the polymerization slows down and the dispersity decreases with the increase in TBABr ratio. Polymers with a narrow molecular weight distribution (dispersity index
      PubDate: 2017-09-26T11:10:26.703103-05:
      DOI: 10.1002/aic.15978
       
  • Globally-Optimal Linear Approach for the Design of Process Equipment: the
           Case of Air Coolers
    • Authors: Priscila A. Souza; André L. H. Costa, Miguel J. Bagajewicz
      Abstract: In a recent article, Gonçalves et al.,11,12 introduced a linear and rigorous methodology for equipment design, in particular shell and tube heat exchanger. Here, we explore its application to air coolers, a problem that we solve globally for the first time. Because the approach is linear, results are globally optimal. The objective function is the total annualized cost. The constraints include the thermal and hydraulic modeling of the process stream flow in the tube bundle and the air flow through the finned surface. In addition, we worked on reducing computing time, through an analysis of different alternatives for the description of the original discrete variables organized in sets of binary variables. The performance of the proposed approach is illustrated through its comparison with an air cooler described in the literature. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-25T11:35:21.95513-05:0
      DOI: 10.1002/aic.15977
       
  • Flow Dynamics in Taylor–Couette Flow Reactor with Axial Distribution
           of Temperature
    • Authors: Hayato Masuda; Saho Yoshida, Takafumi Horie, Makoto Shimoyamada, Naoto Ohmura
      Abstract: In this study, the flow dynamics of a Taylor–Couette flow with an axial distribution of temperature was experimentally investigated. The flow can be classified into three patterns based on the balance between the centrifugal force and the buoyancy. If the buoyancy is dominant, global heat convection is observed instead of Taylor vortices (Case I). When the buoyancy is comparable to the centrifugal force, the Taylor vortices and global heat convection appear alternately (Case II). If the centrifugal force is sufficiently high to suppress the buoyancy, stable Taylor vortices are observed (Case III). The characteristics of the mixing/diffusion are investigated by conducting a decolorization experiment on a passive tracer. In Case II, the tracer is rapidly decolorized in the presence of the global heat convection instead of the Taylor vortices. This result implies that the interaction between the centrifugal force and the buoyancy would induce an anomalous transport. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-21T11:20:57.584634-05:
      DOI: 10.1002/aic.15972
       
  • Characterization of Liquid-Liquid Mass Transfer Performance in a Capillary
           Microreactor System
    • Authors: Guangxiao Li; Minjing Shang, Yang Song, Yuanhai Su
      Abstract: Liquid-liquid mass transfer performance in a capillary microreactor system was studied with an improved experimental method. Proper sampling modes were chosen to eliminate the effect of the sampling zone on the mass transfer characterization in capillary microreactor systems. The overall volumetric mass transfer coefficients in the T-micromixer and the capillary microreactor system were found to smoothly increase and then significantly increase with increasing the Reynolds number of two immiscible liquid phases. Other factors such as the inlet mode and inner diameter of T-micromixer, the capillary length, and the volumetric flux ratio of the aqueous phase to the organic phase affected the mass transfer performance in the T-micromixer and the capillary microreactor system. Furthermore, the contribution of the mass transfer in the T-micromixer zone to the capillary microreactor system was found to be in a range of 34-78% under the involved experimental conditions, which was emphasized in the proposed empirical correlations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-21T11:20:54.627313-05:
      DOI: 10.1002/aic.15973
       
  • Anticancer Drug Delivery Systems based on Inorganic Nanocarriers with
           Fluorescent Tracers
    • Authors: Jiangli Fan; Suzhen Wang, Wen Sun, Shigang Guo, Yao Kang, Jianjun Du, Xiaojun Peng
      Abstract: In recent years, anticancer nanomedicines have mainly been developed for chemotherapy and combination therapy in which the main contributing anticancer drugs are delivered by deliberately designed nano drug delivery systems (nano-DDSs). Inorganic nanocarriers equipped with fluorescent tracers have become attractive tools to monitor the whole drug delivery and release processes. The fluorescence signal of tracers could be observed concomitantly with drug release, and thus this strategy is of great benefit to evaluate the therapeutic effects of the nano-DDSs. This review provides a brief overview about three inorganic nanocarriers for drug delivery, including mesoporous silica, Fe3O4, and hydroxyapatite. We mainly discussed about their preparation processes, drug loading capacities, and the development of different fluorescent materials (fluorescent dyes, quantum dots, fluorescent macromolecules, and rare earth metals) hybridized to nanocarriers for real-time monitoring of drug release both in vitro and in vivo. This review also provides some recommendations for more in-depth research in future. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-21T11:15:52.463262-05:
      DOI: 10.1002/aic.15976
       
  • A New Insight into the Stability of Variable Viscosity Diffusive Boundary
           Layers in Porous Media under Gravity Field
    • Authors: Nasser Sabet; Hassan Hassanzadeh, Jalal Abedi
      Abstract: We study the stability of gravitationally unstable transient diffusive boundary layers with variable viscosity in porous media. The previous studies characterize the effect of viscosity variation only in terms of viscosity contrast and generalize their findings. However, conclusions of different studies seem contradictory. Our results demonstrate that stability of diffusive fronts is governed by the boundary layer viscosity and not solely by the viscosity contrast. In other words, the use of viscosity contrast to ascertain the stability of the system cannot be generalized. Nonlinear simulations are conducted based on a finite difference scheme to validate the results of linear stability analysis for which the amplification theory is adopted. We also revisit other available scaling approaches used to characterize the effect of viscosity variation on the onset of convective dissolution and explain why previously made conclusions are not inclusive and sometimes appeared to be contradictory. A critical Rayleigh number is found to predict stability of Rayleigh-Darcy convection in a porous layer with variable viscosity. The results reveal that this critical value can differ highly from the conventional value of 4π2. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-21T11:15:46.302932-05:
      DOI: 10.1002/aic.15974
       
  • Surface Layer Modification of AEMs by Infiltration and Photo-Cross-Linking
           to Induce Monovalent Selectivity
    • Authors: Huimin Liu; Yuliang Jiang, Jincheng Ding, Wenhui Shi, Jiefeng Pan, Congjie Gao, Bart van der Bruggen, Jiangnan Shen
      Abstract: Surface modification of anion exchange membranes (AEMs) by attaching a negatively charged layer is the main method for preparing monovalent anion selective membranes. However, tremendous increase of membrane resistance and poor long term stability of the modified membranes face great challenges. In this work, a photosensitive molecule (4,4-diazostilbene-2,2-disulfonic acid disodium salt (DAS)) was infiltrated into the membrane surface and immobilized in the structure by cross-linking under UV irradiation. This method introduced negative charge to the surface layer of the AEMs without increasing membrane thickness, leading to high performance membrane with high monovalent anion selectivity. The optimized membrane (D-5) shows the highest perm-selectivity of 11.21, which is superior to the commercial selective membrane Selemion® ASV and previously reported monovalent anion selective AEMs. Furthermore, the newly developed membrane exhibits excellent long-term stability, which can maintain constant selectivity during the 80 h ED experiment. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-21T11:15:29.696738-05:
      DOI: 10.1002/aic.15975
       
  • A Theory of Ultra-Deep Hydrodesulfurization of Diesel in Stacked-Bed
           Reactors
    • 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
           intensification
    • 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
           Principle
    • 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
       
  • 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
       
  • 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
       
  • Model of inertial spreading and imbibition of a liquid drop on a capillary
           plate
    • 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
       
  • 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
           Reactions
    • 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
       
  • On Facilitated Computation of Mesoscopic Behavior of Reaction-Diffusion
           Systems
    • 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
       
  • Issue information - table of contents
    • Pages: 5237 - 5237
      PubDate: 2017-11-02T11:29:43.766841-05:
      DOI: 10.1002/aic.15484
       
  • How nano-scale roughness impacts the flow of grains influenced by
           capillary cohesion
    • Authors: Casey Q. LaMarche; Andrew W. Miller, Peiyuan Liu, Stuart Leadley, Christine M. Hrenya
      Pages: 5250 - 5257
      Abstract: We show that nano-scale changes in surface roughness affect the macro-scale (many-particle) behavior of granular materials influenced by cohesion. Macro-scale effects of roughness are investigated for conditions where cohesion is dominated by either humidity-induced or van der Waals-induced forces. Surface-topography measurements are used to calculate the relevant interparticle cohesive forces. The (force-dominated) macro-scale cohesion measurements are explained via the ratio of the predicted interparticle cohesive force to gravity, thus reinforcing the importance of roughness to cohesion. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5250–5257, 2017
      PubDate: 2017-07-04T15:15:24.438465-05:
      DOI: 10.1002/aic.15830
       
  • CO2 capture in a multistage CFB: Part I: Number of stages
    • Authors: Sutthichai Boonprasop; Dimitri Gidaspow, Benjapon Chalermsinsuwan, Pornpote Piumsomboon
      Pages: 5267 - 5279
      Abstract: The most common technology for postcombustion of CO2 capture is the amine solvent scrubber. The energy consumption for capturing CO2 from flue gases using amine solvent technology is 15–30% of the power plant electricity production. Hence, there is a need to develop more efficient methods of removing CO2. A circulating fluidized bed using sodium or potassium carbonates is potentially such a process, as their high decomposition pressures allow regeneration at low temperatures using waste heat rather than steam from the power plant. But equilibrium data for the sorbents require the use of several cooled stages to achieve high CO2 conversions. Here, a method of computing such a number of stages for a given CO2 conversion was developed using multiphase computational fluid dynamics. It was found that it required six equilibrium stages to remove 96% of CO2 with the initial mole fraction of 0.15 in a sorption riser. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5267–5279, 2017
      PubDate: 2017-05-14T18:16:05.821873-05:
      DOI: 10.1002/aic.15776
       
  • CO2 capture in a multistage CFB: Part II: Riser with multiple cooling
           stages
    • Authors: Sutthichai Boonprasop; Dimitri Gidaspow, Benjapon Chalermsinsuwan, Pornpote Piumsomboon
      Pages: 5280 - 5289
      Abstract: A 1 m in diameter and 3.55 m tall fluidized bed riser internally with water tubes, which required six equilibrium stage of riser-sorber for capturing about 95% of CO2 emitted from a coal power plant, were designed to replace the multisingle risers. At the optimum operating condition, the temperature of the cooling tubes in the bottom, the middle and the top of the riser were kept constant values at 50, 40, and 30°C, respectively. The hot water (57°C) from lowest exchanger section can be used to preheat the spent sorbent for the regeneration in a downer. The rest of the heat for the regenertion is obtained from the stack gas (100–130°C). This new concept promises to reduce the energy consumption for CO2 removal from flue gas. The only energy requirement is for pumping fluid and fluidizing particles in the bed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5280–5289, 2017
      PubDate: 2017-05-14T18:23:26.344589-05:
      DOI: 10.1002/aic.15777
       
  • Analysis of the effect of small amounts of liquid on gas–solid
           fluidization using CFD-DEM simulations
    • Authors: C. M. Boyce; A. Ozel, J. Kolehmainen, S. Sundaresan
      Pages: 5290 - 5302
      Abstract: Gas–solid fluidization involving small amounts of liquid is simulated using a CFD-DEM model. The model tracks the amount of liquid on each particle and wall element and incorporates finite rates of liquid transfer between particles and pendular liquid bridges which form between two particles as well as between a particle and a wall element. Viscous and capillary forces due to these bridges are modeled. Fluidization–defluidization curves show that minimum fluidization velocity and defluidized bed height increase with Bond number (Bo), the ratio of surface tension to gravitational forces, due to cohesion and inhomogeneous flow structures. Under fluidized conditions, hydrodynamics and liquid bridging behavior change dramatically with increasing Bo, and to a lesser extent with capillary number, the ratio of viscous to surface tension forces. Bed fluidity is kept relatively constant across wetting conditions when one maintains a constant ratio of superficial velocity to minimum fluidization velocity under wet conditions. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5290–5302, 2017
      PubDate: 2017-06-21T18:36:04.878746-05:
      DOI: 10.1002/aic.15819
       
  • Coaxial electrohydrodynamic atomization toward large scale production of
           core-shell structured microparticles
    • Authors: Wei-Cheng Yan; Yen Wah Tong, Chi-Hwa Wang
      Pages: 5303 - 5319
      Abstract: In this work, a double-nozzle coaxial electrohydrodynamic atomization (CEHDA) system was designed as an instructive case toward large-scale production of core-shell microspheres. The effect of nozzle-to-nozzle distance was investigated to reveal that the interference between neighboring nozzles significantly affect the product quality in terms of morphology and core-shell structure. Optimal spacing indicated that ∼3000 nozzle/m2 packing density may be achieved with minimum interference of electric field from neighboring nozzle by adjusting the nozzle-to-nozzle distance greater than 0.018 m. The proposed multi-scale model also showed that the X-component of electric field strength (Ex) at the region near side nozzles increases with increasing nozzle number, and the bending of jets/sprays at the side may be reduced by using dummy nozzle at the edge side. The model could guide the design of multi-nozzle CEHDA system for production of core-shell microparticles in large-scale. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5303–5319, 2017
      PubDate: 2017-06-29T08:11:12.972435-05:
      DOI: 10.1002/aic.15821
       
  • An efficient and reliable predictive method for fluidized bed simulation
    • Authors: Liqiang Lu; Sofiane Benyahia, Tingwen Li
      Pages: 5320 - 5334
      Abstract: In past decades, the continuum approach was the only practical technique to simulate large-scale fluidized bed reactors because discrete approaches suffer from the cost of tracking huge numbers of particles and their collisions. This study significantly improved the computation speed of discrete particle methods in two steps: First, the time-driven hard-sphere (TDHS) algorithm with a larger time-step is proposed allowing a speedup of 20–60 times; second, the number of tracked particles is reduced by adopting the coarse-graining technique gaining an additional 2–3 orders of magnitude speedup of the simulations. A new velocity correction term was introduced and validated in TDHS to solve the over-packing issue in dense granular flow. The TDHS was then coupled with the coarse-graining technique to simulate a pilot-scale riser. The simulation results compared well with experiment data and proved that this new approach can be used for efficient and reliable simulations of large-scale fluidized bed systems. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5320–5334, 2017
      PubDate: 2017-06-29T08:31:35.569024-05:
      DOI: 10.1002/aic.15832
       
  • Magnetic particle tracking for nonspherical particles in a cylindrical
           fluidized bed
    • Authors: Kay A. Buist; Pavithra Jayaprakash, J.A.M. Kuipers, Niels G. Deen, Johan T. Padding
      Pages: 5335 - 5342
      Abstract: In granular flow operations, often particles are nonspherical. This has inspired a vast amount of research in understanding the behavior of these particles. Various models are being developed to study the hydrodynamics involving nonspherical particles. Experiments however are often limited to obtain data on the translational motion only. This paper focusses on the unique capability of Magnetic Particle Tracking to track the orientation of a marker in a full 3-D cylindrical fluidized bed. Stainless steel particles with the same volume and different aspect ratios are fluidized at a range of superficial gas velocities. Spherical and rod-like particles show distinctly different fluidization behavior. Also, the distribution of angles for rod-like particles changes with position in the fluidized bed as well as with the superficial velocity. Magnetic Particle Tracking shows its unique capability to study both spatial distribution and orientation of the particles allowing more in-depth validation of Discrete Particle Models. © 2017 The
      Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 63: 5335–5342, 2017
      PubDate: 2017-07-18T11:30:56.3055-05:00
      DOI: 10.1002/aic.15854
       
  • Quantifying the uncertainty introduced by discretization and
           time-averaging in two-fluid model predictions
    • Authors: Madhava Syamlal; Ismail B. Celik, Sofiane Benyahia
      Pages: 5343 - 5360
      Abstract: The two-fluid model (TFM) has become a tool for the design and troubleshooting of industrial fluidized bed reactors. To use TFM for scale up with confidence, the uncertainty in its predictions must be quantified. Here, we study two sources of uncertainty: discretization and time-averaging. First, we show that successive grid refinement may not yield grid-independent transient quantities, including cross-section–averaged quantities. Successive grid refinement would yield grid-independent time-averaged quantities on sufficiently fine grids. Then a Richardson extrapolation can be used to estimate the discretization error, and the grid convergence index gives an estimate of the uncertainty. Richardson extrapolation may not work for industrial-scale simulations that use coarse grids. We present an alternative method for coarse grids and assess its ability to estimate the discretization error. Second, we assess two methods (autocorrelation and binning) and find that the autocorrelation method is more reliable for estimating the uncertainty introduced by time-averaging TFM data. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5343–5360, 2017
      PubDate: 2017-07-24T15:41:54.104276-05:
      DOI: 10.1002/aic.15868
       
  • 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
      Pages: 5361 - 5374
      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 nonintrusive 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-optic probe for more accurate characterization. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5361–5374, 2017
      PubDate: 2017-08-12T18:41:00.283165-05:
      DOI: 10.1002/aic.15892
       
  • CFD simulation of the effect of rain on the performance of horizontal wind
           turbines
    • Authors: Hamid Arastoopour; Aiden Cohan
      Pages: 5375 - 5383
      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, simplifying assumptions were made and the validity of these assumptions was verified 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5375–5383, 2017
      PubDate: 2017-08-29T11:55:35.711142-05:
      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
      Pages: 5384 - 5395
      Abstract: Discrete Element Method 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: 2017-08-29T11:55:44.24063-05:0
      DOI: 10.1002/aic.15933
       
  • Process flow sheet synthesis: Systems-level design applied to synthetic
           crude production
    • Authors: James Alistair Fox; Diane Hildebrandt, David Glasser, Bilal Patel
      Pages: 5413 - 5424
      Abstract: A novel approach for conceptual design for process flow sheets at the “systems-level” is showcased in this article. A graphical technique, called the “GH-space,” is used to analyze the flows of material, heat and work within a process to provide insight into the interactions of various units within the process. Any unit process, which interacts with the surroundings by transferring heat and work, can be represented as a vector on the GH-space. While material and energy balances are normally performed on a flowsheet, this vectored approach allows the material and energy balances to be used to construct a flowsheet. This article focuses on using the GH-space to synthesis a synthetic fuels flowsheet. It was shown that a process could be designed that not only produced the desired product but could also consume carbon dioxide as a feed, along with the feeds of methane and oxygen, and could even potentially generate electricity. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5413–5424, 2017
      PubDate: 2017-06-19T18:06:30.139055-05:
      DOI: 10.1002/aic.15818
       
  • Biochar soil amendments for increased crop yields: How to design a
           “designer” biochar
    • Authors: Kyriacos Zygourakis
      Pages: 5425 - 5437
      Abstract: 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 is presented in this study. 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5425–5437, 2017
      PubDate: 2017-07-28T08:01:43.260137-05:
      DOI: 10.1002/aic.15870
       
  • Complete carbon analysis of sulfur-containing mixtures using postcolumn
           reaction and flame ionization detection
    • Authors: Connor A. Beach; Kristeen E. Joseph, Paul J. Dauenhauer, Charles S. Spanjers, Andrew J. Jones, Triantafillos J. Mountziaris
      Pages: 5438 - 5444
      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 3-D–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 2000 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. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5438–5444, 2017
      PubDate: 2017-08-03T11:05:47.014848-05:
      DOI: 10.1002/aic.15888
       
  • Kinetics of glycerol conversion to hydrocarbon fuels over Pd/H-ZSM-5
           catalyst
    • Authors: Yang Xiao; Arvind Varma
      Pages: 5445 - 5451
      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%. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5445–5451, 2017
      PubDate: 2017-08-25T08:55:55.840184-05:
      DOI: 10.1002/aic.15931
       
 
 
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