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  Subjects -> ENGINEERING (Total: 2251 journals)
    - CHEMICAL ENGINEERING (188 journals)
    - CIVIL ENGINEERING (179 journals)
    - ELECTRICAL ENGINEERING (98 journals)
    - ENGINEERING (1194 journals)
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    - MECHANICAL ENGINEERING (89 journals)

ENGINEERING (1194 journals)            First | 1 2 3 4 5 6 | Last

Showing 201 - 400 of 1205 Journals sorted alphabetically
Current Science     Open Access   (Followers: 39)
Dams and Reservoirs     Hybrid Journal   (Followers: 3)
Data Handling in Science and Technology     Full-text available via subscription   (Followers: 6)
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 27)
Designed Monomers and Polymers     Hybrid Journal  
Designs, Codes and Cryptography     Hybrid Journal   (Followers: 6)
Development Engineering     Open Access  
Developments in Clay Science     Full-text available via subscription   (Followers: 1)
Developments in Geotechnical Engineering     Full-text available via subscription   (Followers: 4)
Developments in Mineral Processing     Full-text available via subscription   (Followers: 3)
Diálogos Interdisciplinares     Open Access  
Diffusion Foundations     Full-text available via subscription  
Digital Signal Processing     Hybrid Journal   (Followers: 12)
Discrete Optimization     Full-text available via subscription   (Followers: 5)
Doct-Us Journal     Open Access  
Documents pour l'histoire des techniques     Open Access   (Followers: 1)
Dyes and Pigments     Hybrid Journal   (Followers: 1)
Dyna     Open Access  
Dynamical Systems : An International Journal     Hybrid Journal  
E&S Engineering and Science     Open Access  
El Hombre y la Máquina     Open Access  
Electromagnetics     Hybrid Journal   (Followers: 4)
Electrophoresis     Hybrid Journal   (Followers: 19)
Elementos     Open Access  
Elsevier Geo-Engineering Book Series     Full-text available via subscription   (Followers: 2)
Elsevier Ocean Engineering Series     Full-text available via subscription  
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 38)
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations     Open Access   (Followers: 1)
Energies     Open Access   (Followers: 3)
Energy and Power Engineering     Open Access   (Followers: 16)
Energy Conversion and Management     Hybrid Journal   (Followers: 8)
Energy Engineering     Full-text available via subscription   (Followers: 9)
Energy for Sustainable Development     Hybrid Journal   (Followers: 9)
Energy Procedia     Open Access   (Followers: 2)
Energy Science & Engineering     Open Access   (Followers: 3)
Energy Science and Technology     Open Access   (Followers: 12)
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects     Hybrid Journal   (Followers: 1)
Energy Sources, Part B: Economics, Planning, and Policy     Hybrid Journal   (Followers: 6)
Energy Systems     Hybrid Journal   (Followers: 12)
ENGEVISTA     Open Access   (Followers: 1)
ENGI : Revista Electrónica de la Facultad de Ingenieria     Open Access  
Engineer : Journal of the Institution of Engineers, Sri Lanka     Open Access  
Engineering     Open Access   (Followers: 1)
Engineering & Technology     Hybrid Journal   (Followers: 22)
Engineering : The official journal of the Chinese Academy of Engineering and Higher Education Press     Open Access   (Followers: 1)
Engineering Analysis with Boundary Elements     Hybrid Journal   (Followers: 1)
Engineering Computations     Hybrid Journal   (Followers: 3)
Engineering Economics     Open Access   (Followers: 4)
Engineering Economist, The     Hybrid Journal   (Followers: 6)
Engineering Failure Analysis     Hybrid Journal   (Followers: 64)
Engineering Geology     Hybrid Journal   (Followers: 9)
Engineering International     Open Access  
Engineering Journal     Open Access   (Followers: 1)
Engineering Management Journal     Hybrid Journal   (Followers: 19)
Engineering Management Research     Open Access   (Followers: 6)
Engineering Management Reviews     Open Access   (Followers: 1)
Engineering Optimization     Hybrid Journal   (Followers: 7)
Engineering Science and Technology, an International Journal     Open Access   (Followers: 1)
Engineering Sciences     Open Access   (Followers: 1)
Engineering Studies     Hybrid Journal  
Engineering With Computers     Hybrid Journal   (Followers: 7)
Engineering, Technology & Applied Science Research     Open Access  
Entramado     Open Access  
Entropy     Open Access   (Followers: 4)
Environmental & Engineering Geoscience     Full-text available via subscription   (Followers: 3)
Environmental and Ecological Statistics     Hybrid Journal   (Followers: 6)
Environmetrics     Hybrid Journal  
Épités - Épitészettudomány     Full-text available via subscription   (Followers: 1)
EPJ Photovoltaics     Open Access   (Followers: 2)
Épsilon     Open Access  
Ergonomics in Design: The Quarterly of Human Factors Applications     Hybrid Journal   (Followers: 14)
ESAIM: Control Optimisation and Calculus of Variations     Full-text available via subscription   (Followers: 1)
ESAIM: Mathematical Modelling and Numerical Analysis     Full-text available via subscription   (Followers: 4)
ESAIM: Proceedings     Open Access  
Estuaries and Coasts     Hybrid Journal   (Followers: 17)
European Journal of Combinatorics     Full-text available via subscription   (Followers: 3)
European Journal of Engineering Education     Hybrid Journal   (Followers: 3)
European Journal of Lipid Science and Technology     Hybrid Journal   (Followers: 1)
European Journal of Mass Spectrometry     Full-text available via subscription   (Followers: 16)
European Medical Device Technology     Full-text available via subscription   (Followers: 3)
European Physical Journal - Applied Physics     Full-text available via subscription   (Followers: 7)
European Transport Research Review     Open Access   (Followers: 21)
Evolutionary Intelligence     Hybrid Journal   (Followers: 1)
Evolving Systems     Hybrid Journal  
Exacta     Open Access  
Experimental Techniques     Hybrid Journal   (Followers: 56)
Experiments in Fluids     Hybrid Journal   (Followers: 10)
Fibers and Polymers     Full-text available via subscription   (Followers: 4)
Filtration & Separation     Full-text available via subscription   (Followers: 4)
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 4)
Fire Science Reviews     Open Access   (Followers: 5)
Flexible Services and Manufacturing Journal     Hybrid Journal   (Followers: 1)
Flow, Turbulence and Combustion     Hybrid Journal   (Followers: 24)
Fluid Dynamics     Hybrid Journal   (Followers: 10)
Fluid Dynamics Research     Full-text available via subscription   (Followers: 10)
Fluid Phase Equilibria     Hybrid Journal   (Followers: 4)
Focus on Catalysts     Full-text available via subscription  
Focus on Pigments     Full-text available via subscription   (Followers: 3)
Focus on Powder Coatings     Full-text available via subscription   (Followers: 3)
Focus on Surfactants     Full-text available via subscription   (Followers: 3)
Food Engineering Reviews     Hybrid Journal   (Followers: 3)
Food Science and Technology     Open Access   (Followers: 3)
Formación Universitaria     Open Access   (Followers: 3)
FORMakademisk     Open Access  
Formal Methods in System Design     Hybrid Journal   (Followers: 6)
Forschung     Hybrid Journal  
Forschung im Ingenieurwesen     Hybrid Journal   (Followers: 1)
Foundations and Trends in Systems and Control     Full-text available via subscription  
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 7)
Foundations and Trends® in Electronic Design Automation     Full-text available via subscription  
Foundations of Science     Hybrid Journal   (Followers: 1)
Frontiers in Aerospace Engineering     Open Access   (Followers: 10)
Frontiers in Energy     Hybrid Journal   (Followers: 3)
Frontiers in Geotechnical Engineering     Open Access   (Followers: 2)
Frontiers of Environmental Science & Engineering     Hybrid Journal   (Followers: 4)
Frontiers of Nanoscience     Full-text available via subscription   (Followers: 1)
Fuel and Energy Abstracts     Full-text available via subscription   (Followers: 5)
Fuel Cells     Hybrid Journal   (Followers: 3)
Fuel Cells Bulletin     Full-text available via subscription   (Followers: 4)
Fusion Engineering and Design     Hybrid Journal   (Followers: 9)
Fuzzy Information and Engineering     Open Access   (Followers: 3)
Fuzzy Sets and Systems     Hybrid Journal   (Followers: 4)
Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards     Hybrid Journal   (Followers: 8)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 138)
Geotechnical Testing Journal     Full-text available via subscription   (Followers: 9)
Géotechnique     Hybrid Journal   (Followers: 12)
Geothermics     Hybrid Journal   (Followers: 6)
Glass Technology - European Journal of Glass Science and Technology Part A     Full-text available via subscription   (Followers: 3)
Global Journal of Engineering Research     Full-text available via subscription  
Global Perspective on Engineering Management     Open Access   (Followers: 2)
GPS Solutions     Hybrid Journal   (Followers: 17)
Graphs and Combinatorics     Hybrid Journal   (Followers: 6)
Grass and Forage Science     Hybrid Journal   (Followers: 6)
Great Circle: Journal of the Australian Association for Maritime History, The     Full-text available via subscription   (Followers: 8)
Groundwater for Sustainable Development     Full-text available via subscription  
Handai Nanophotonics     Full-text available via subscription  
Handbook of Adhesives and Sealants     Full-text available via subscription   (Followers: 1)
Handbook of Sensors and Actuators     Full-text available via subscription   (Followers: 8)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 3)
Heat Exchangers     Open Access   (Followers: 1)
Heat Transfer - Asian Research     Hybrid Journal   (Followers: 9)
Heat Transfer Engineering     Hybrid Journal   (Followers: 24)
Historical Records of Australian Science     Hybrid Journal   (Followers: 2)
Human Factors in Ergonomics & Manufacturing     Hybrid Journal   (Followers: 6)
IBM Journal of Research and Development     Hybrid Journal   (Followers: 17)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 44)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 36)
IEEE Communications Magazine     Full-text available via subscription   (Followers: 65)
IEEE Control Systems Magazine     Full-text available via subscription   (Followers: 66)
IEEE Engineering Management Review     Full-text available via subscription   (Followers: 33)
IEEE Geoscience and Remote Sensing Letters     Hybrid Journal   (Followers: 133)
IEEE Industry Applications Magazine     Full-text available via subscription   (Followers: 18)
IEEE Instrumentation & Measurement Magazine     Full-text available via subscription   (Followers: 57)
IEEE Journal of Biomedical and Health Informatics     Hybrid Journal   (Followers: 14)
IEEE Journal of Oceanic Engineering     Hybrid Journal   (Followers: 11)
IEEE Journal of Selected Topics in Quantum Electronics     Hybrid Journal   (Followers: 9)
IEEE Journal of Selected Topics in Signal Processing     Hybrid Journal   (Followers: 28)
IEEE Journal of Solid-State Circuits     Full-text available via subscription   (Followers: 20)
IEEE Journal on Selected Areas in Communications     Hybrid Journal   (Followers: 17)
IEEE Latin America Transactions     Full-text available via subscription   (Followers: 2)
IEEE Microwave and Wireless Components Letters     Hybrid Journal   (Followers: 16)
IEEE Microwave Magazine     Full-text available via subscription   (Followers: 28)
IEEE Potentials     Full-text available via subscription   (Followers: 18)
IEEE Signal Processing Letters     Hybrid Journal   (Followers: 34)
IEEE Spectrum     Full-text available via subscription   (Followers: 137)
IEEE Technology and Society Magazine     Full-text available via subscription   (Followers: 5)
IEEE Transactions on Advanced Packaging     Full-text available via subscription   (Followers: 7)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 36)
IEEE Transactions on Applied Superconductivity     Hybrid Journal   (Followers: 4)
IEEE Transactions on Automation Science and Engineering     Full-text available via subscription   (Followers: 12)
IEEE Transactions on Circuits and Systems II: Express Briefs     Hybrid Journal   (Followers: 16)
IEEE Transactions on Components and Packaging Technologies     Full-text available via subscription   (Followers: 15)
IEEE Transactions on Control Systems Technology     Hybrid Journal   (Followers: 44)
IEEE Transactions on Education     Hybrid Journal   (Followers: 7)
IEEE Transactions on Electronics Packaging Manufacturing     Full-text available via subscription   (Followers: 19)
IEEE Transactions on Energy Conversion     Hybrid Journal   (Followers: 11)
IEEE Transactions on Engineering Management     Hybrid Journal   (Followers: 25)
IEEE Transactions on Evolutionary Computation     Hybrid Journal   (Followers: 9)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 18)
IEEE Transactions on Instrumentation and Measurement     Hybrid Journal   (Followers: 49)
IEEE Transactions on Intelligent Transportation Systems     Hybrid Journal   (Followers: 7)
IEEE Transactions on Knowledge and Data Engineering     Hybrid Journal   (Followers: 30)
IEEE Transactions on Magnetics     Hybrid Journal   (Followers: 12)
IEEE Transactions on Microwave Theory and Techniques     Hybrid Journal   (Followers: 24)
IEEE Transactions on Nuclear Science     Hybrid Journal   (Followers: 8)
IEEE Transactions on Plasma Science     Hybrid Journal   (Followers: 7)
IEEE Transactions on Power Delivery     Hybrid Journal   (Followers: 17)
IEEE Transactions on Professional Communication     Hybrid Journal   (Followers: 6)
IEEE Transactions on Reliability     Hybrid Journal   (Followers: 32)
IEEE Transactions on Semiconductor Manufacturing     Hybrid Journal   (Followers: 6)
IEEE Transactions on Signal Processing     Hybrid Journal   (Followers: 61)
IEEE Transactions on Vehicular Technology     Hybrid Journal   (Followers: 3)
IEEE Vehicular Technology Magazine     Full-text available via subscription   (Followers: 8)
IEEE/ACM Transactions on Computational Biology and Bioinformatics     Hybrid Journal   (Followers: 17)
IERI Procedia     Open Access  
IET Circuits, Devices & Systems     Hybrid Journal   (Followers: 18)
IET Generation, Transmission & Distribution     Hybrid Journal   (Followers: 2)
IET Image Processing     Hybrid Journal   (Followers: 13)
IET Micro and Nano Letters     Hybrid Journal   (Followers: 6)
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 12)

  First | 1 2 3 4 5 6 | Last

Journal Cover AIChE Journal
  [SJR: 1.122]   [H-I: 120]   [27 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  [1611 journals]
  • Shell and Tube Heat Exchanger Design Using Mixed-Integer Linear
    • Authors: Caroline de O. Gonçalves; André L. H. Costa, Miguel J. Bagajewicz
      Abstract: The design of heat exchangers, especially shell and tube heat exchangers was originally proposed as a trial and error procedure where guesses of the heat transfer coefficient were made and then verified after the design was finished. This traditional approach is highly dependent of the experience of a skilled engineer and it usually results in oversizing. Later, optimization techniques were proposed for the automatic generation of the best design alternative. Among these methods, there are heuristic and stochastic approaches as well as mathematical programming. In all cases, the models are mixed integer non-linear and non-convex. In the case of mathematical programming solution procedures, all the solution approaches were likely to be trapped in a local optimum solution, unless global optimization is used. In addition, it is very well-known that local solvers need good initial values or sometimes they do not even find a feasible solution. In this article, we propose to use a robust mixed integer global optimization procedure to obtain the optimal design. Our model is linear thanks to the use of standardized and discrete geometric values of the heat exchanger main mechanical components and a reformulation of integer nonlinear expressions without losing any rigor. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-22T03:55:34.576047-05:
      DOI: 10.1002/aic.15556
  • Experimental Study on CH* Chemiluminescence Characteristics of Impinging
           Flames in an Opposed Multi-Burner Gasifier
    • Authors: Qing Zhang; Yan Gong, Qinghua Guo, Xudong Song, Guangsuo Yu
      Abstract: The bandpass filtered images of impinging flames in an opposed multi-burner (OMB) gasifier was visualized by a CCD camera combined with a high temperature endoscope. A filtering and image processing method by use of three bandpass filters was applied to subtract soot and CO2* contributions in the CH* band and obtain the CH* chemiluminescence of impinging flames. The results show that a clear reaction core is generated in the impinging zone of four-burner impinging flames. The size of the reaction core is affected by the O/C equivalence ratio ([O/C]e) and the impingement effect is relatively stronger at lower [O/C]e. The flame lift-off length in the gasifier is jointly controlled by the syngas concentration and the diesel atomization effect. The impingement effect shortens the flame lift-off length. The relationship between the syngas concentration and the maximum CH* intensity makes it possible to evaluate the syngas concentration from CH* intensity. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-22T03:55:29.687214-05:
      DOI: 10.1002/aic.15555
  • A Critical Look into Effects of Electrode Pore Morphology in Solid Oxide
           Fuel Cells
    • Authors: Yinghua Niu; Weiqiang Lv, Gaofeng Rao, Jiarui He, Weidong He
      Abstract: Knudsen diffusion, an important form of gas transport in sub-micro/nanoscale porous electrodes of solid oxide fuel cells (SOFCs), is evaluated typically based on the assumption of isotropic cross-sections of electrode pores. As a consequence, errors are induced in the evaluation of gas transport and polarization loss of SOFCs with irregular, anisotropic pore morphology. Here, a numerical model is derived to investigate the impact of pore morphology on Knudsen diffusivity and effective total diffusivity in porous SOFC electrodes. Based on the model, the correlation between pore morphology and important parameters of SOFCs, including limiting current density (LCD) and concentration polarization (CP), is evaluated. As the aspect ratio of pore cross-section increases, the gas diffusivity in SOFC electrodes decreases, and then nontrivial variations in LCD and CP are induced. This work facilitates the accurate evaluation of gas transport in SOFCs as well as the rational design of electrode microstructure of SOFCs. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-19T10:31:45.634375-05:
      DOI: 10.1002/aic.15554
  • Phase Separation of Gas-Liquid Two-Phase Stratified and Plug Flows in
           Multi-Tube T-Junction Separators
    • Authors: Limin Yang; Jiahao Wang, Barry J Azzopardi, Zhenying Zhao, Shengbo Xu, Hong Wang
      Abstract: Using air and water as the working fluids, phase separation phenomena for stratified and plug flows at inlet were investigated experimentally, at a simple T-junction and specifically designed multi-tube T-junction separators with 2 or 3 layers. The results show that for these two flow patterns the separation efficiency of the two phases for any multi-tube T-junction separator is much higher than that of the simple T-junction. Increasing the number of connecting tubes in the multi-tube T-junction separator can increase the separation efficiency. Generally, for stratified flow, complete separation of the two phases can be achieved by the 2-layer multi-tube T-junction separator with 5 or more connecting tubes and by the 3-layer separator; increasing the gas flow rate, the liquid flow rate, or the mixture velocity under plug flow is detrimental to phase separation with a drop in peak separation efficiency. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-17T17:50:53.616299-05:
      DOI: 10.1002/aic.15552
  • An Economic Model Predictive Control Approach to Integrated Production
           Management and Process Operation
    • Authors: Anas Alanqar; Helen Durand, Fahad Albalawi, Panagiotis D. Christofides
      Abstract: Managing production schedules and tracking time-varying demand of certain products while optimizing process economics are subjects of central importance in industrial applications. We investigate the use of economic model predictive control (EMPC) in tracking a production schedule. Specifically, given that only a small subset of the total process state vector is typically required to track certain scheduled values, we design a novel EMPC scheme, through proper construction of the objective function and constraints, that forces specific process states to meet the production schedule and varies the rest of the process states in a way that optimizes process economic performance. Conditions under which feasibility and closed-loop stability of a nonlinear process under such an EMPC for schedule management can be guaranteed are developed. The proposed EMPC scheme is demonstrated through a chemical process example in which the product concentration is requested to follow a certain production schedule. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-17T17:25:43.676603-05:
      DOI: 10.1002/aic.15553
  • Conversion of Carbohydrates into 5-Hydroxymethylfurfural in a Green
           Reaction System of CO2-Water-Isopropanol
    • Authors: Haizhou Lin; Qingang Xiong, Yuan Zhao, Jingping Chen, Shurong Wang
      Abstract: In this work, a green reaction system of CO2-water-isopropanol was developed for 5-hydroxymethylfurfural (HMF) production. The conversion of fructose in a CO2-water system was first investigated, and the results showed this system could promote the formation of HMF compared to a pure water system. Then, isopropanol was introduced into the CO2-water system and the HMF formation became better because the solvent effect of isopropanol increased the tautomeric composition of fructofuranose, which was easy to form HMF. The existence of isopropanol was found to greatly suppress secondary reactions where HMF was converted to levulinic acid (LA) and insoluble humin. Meanwhile, the effects of reaction parameters on the conversion of fructose to HMF in the CO2-water-isopropanol system were analyzed, and a high HMF yield of 67.14% was obtained. Finally, to further illustrate the merits of CO2-water-isopropanol system, productions of HMF from other carbohydrates were tested and satisfactory yields were achieved. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-17T17:25:40.144243-05:
      DOI: 10.1002/aic.15550
  • Simulation of NOx and Soot Abatement with Cu-Cha and Fe-ZSM5 Catalysts
    • Authors: Samir Bensaid; Vemuri Balakotaiah, Dan Luss
      Abstract: The embodiment of the NOx selective catalytic reduction (SCR) functionality in a diesel particulate filter (DPF), so-called SCR-on-Filter (SCRoF), is investigated through numerical modeling with SCR kinetics corresponding to Cu-Chabazite and Fe-ZSM5 catalysts. The results of the simulations of the SCR activity, performed in the absence and presence of soot, indicate that the presence of soot negligibly affects the NOx conversion efficiency, given the slow dynamics of passive regeneration. Conversely, the reduction in cake thickness by soot passive oxidation is significantly different in the absence of SCR activity (uncatalyzed DPF) compared to that in its presence (SCRoF). In fact, in the SCRoF only 60% to 80% of the original soot consumption obtained in the absence of SCR reaction over 1h can be achieved. Individual Cu-Chabazite and Fe-ZSM5 catalysts, as well as in-series layers of the two catalysts, are investigated in order to devise the widest temperature window for SCRoF. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-17T17:25:33.979157-05:
      DOI: 10.1002/aic.15551
  • Optical methods to investigate the enhancement factor of an
           oxygen-sensitive colorimetric reaction using microreactors
    • Authors: Lixia Yang; Nicolas Dietrich, Karine Loubière, Christophe Gourdon, Gilles Hébrard
      Abstract: Visualization of mass transfer is a powerful tool to improve understanding of local phenomenon. The use of an oxygen-sensitive dye (colorimetric technique1) has showed its relevancy for locally visualizing and characterizing gas-liquid mass transfer at different scales2,3. At present, the occurrence of a possible enhancement of the gas-liquid mass transfer by this reaction has not been yet demonstrated. This paper aims at filling this gap by evaluating the Hatta number Ha and the enhancement factor E associated with the oxygen colorimetric reaction when implementing in milli/micro channels. For that, as data on the kinetic of the colorimetric reaction are seldom in the literature, the reaction characteristic time was firstly estimated by carrying out experiments in a microchannel equipped with a micromixer. The diffusion coefficients of dihydroresorufin and O2 were then determined by implementing two original optical methods in a specific coflow microchannel device, coupled with theoretical modelling. The knowledge of these parameters enabled at last to demonstrate that no enhancement of the gas-liquid mass transfer by this colorimetric reaction existed. Complementary information about the reliability of the colorimetric technique to characterize the gas-liquid mass transfer in milli/micro systems was also given. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-14T03:51:23.57402-05:0
      DOI: 10.1002/aic.15547
  • Ceria-based Nanomaterials as Catalysts for CO Oxidation and Soot
           Combustion: Effect of Zr-Pr Doping and Structural Properties on the
           Catalytic Activity
    • Authors: Marco Piumetti; Tahrizi Andana, Samir Bensaid, Debora Fino, Nunzio Russo, Raffaele Pirone
      Abstract: In this work, we investigated a set of ceria-based catalysts prepared by the hydrothermal and solution combustion synthesis (SCS). For the first time to our knowledge, we synthesized nanocubes of ceria doped with zirconium and praseodymium. The catalysts were tested for the CO and soot oxidation reactions. These materials exhibited different surface reducibility, as measured by H2-TPR, CO-TPR and Soot-TPR, despite their comparable chemical compositions. As a whole, Soot-TPR appears a suitable characterization technique for the soot oxidation catalysts, whereas CO-TPR technique allows to better discriminate among the CO oxidation activities. Praseodymium contributes positively towards the soot oxidation. On the other hand, it has an adverse effect on the CO oxidation over the same catalysts, as compared to pure ceria. The incorporation of zirconium into the ceria lattice does not have a direct beneficial effect on the soot oxidation activity, although it increases the catalyst performances for CO oxidation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-13T18:11:11.712442-05:
      DOI: 10.1002/aic.15548
  • Process intensification of gas-liquid downflow and upflow packed beds by a
           new low-shear rotating reactor concept
    • Authors: Amir Motamed Dashliborun; Hans-Ulrich Härting, Markus Schubert, Faïçal Larachi
      Abstract: In the present work, a new low-shear rotating reactor concept was introduced for process intensification of heterogeneous catalytic reactions in cocurrent gas-liquid downflow and upflow packed-bed reactors. In order to properly assess potential advantages of this new reactor concept, exhaustive hydrodynamic experiments were carried out using embedded low-intrusive wire mesh sensors. The effect of rotational velocities on liquid flow patterns in the bed cross-section, liquid saturation, pressure drop, and regime transition was investigated. Furthermore, liquid residence time and Péclet number estimated by a stimulus-response technique and a macro-mixing model were presented and discussed with respect to the prevailing flow patterns. The results revealed that the column rotation induces different flow patterns in the cross-section of packed bed operating in a concurrent downflow or upflow mode. Moreover, the new reactor concept exhibits a more flexible adjustment of pressure drop, liquid saturation, liquid residence time and back-mixing at constant flow rates. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-13T18:11:03.118072-05:
      DOI: 10.1002/aic.15549
  • Electrochemical reaction engineering of polymer electrolyte fuel cell
    • Authors: M. Kawase; K. Sato, R. Mitsui, H. Asonuma, M. Kageyama, K. Yamaguchi, G. Inoue
      Abstract: Although fuel cells can be considered as a type of reactor, methods of kinetic analysis and reactor modeling from the viewpoint of chemical reaction engineering have not yet been established. The rate of an electrochemical reaction is a function of concentration, temperature, and interfacial potential difference (or electromotive force). This study examined the cathode reaction in a polymer electrolyte fuel cell, in which oxygen and protons react over platinum in the catalyst layer. The effects of the oxygen partial pressure and the cathode electromotive force on the reaction rate were assessed. Resistance to proton transport increases the electromotive force and reducing the reaction rate. It was established that the effectiveness factor of the cathode catalyst layer is determined by competition between the reaction and mass transport of oxygen and protons. Two dimensionless moduli that govern the cathode behavior are proposed as a means of depicting the processes in the cell. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-12T18:01:21.846047-05:
      DOI: 10.1002/aic.15545
  • Methanol Synthesis in a Three-Phase Catalytic Bed under Nonwetted
    • Authors: Dan Ling; Peng Liu, Zhen-Min Cheng
      Abstract: To overcome the heat removal problem encountered in methanol synthesis at high syngas concentrations in the gas phase, a three-phase nonwetted catalytic system was established by introducing an inert liquid medium into a fixed-bed reactor. To form a repellent interface between the liquid and the catalyst, the catalyst was modified into hydrophobic, while the liquid medium was chosen as a room temperature ionic liquid with hydroxyl groups. The liquid-solid contact angle was measured to be 115°, and only 20% of the catalyst external surface was wetted by the liquid. Under three-phase condition, the reaction rate was measured to be 60% - 70% of gas phase reaction, while it was merely 10% - 20% for the fully wetted catalyst. From the resistance analysis on the mass transfer and reaction steps, the overall reaction rate is expected to increase further if the surface could be more wet proofed. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-12T18:01:19.203213-05:
      DOI: 10.1002/aic.15543
  • Reaction Engineering with Enzymes: A Relatively Uncharted Territory
    • Authors: Judit E. Puskas; Jozsef Kantor, Gayatri Shrikhande
      Abstract: This paper discusses the history of enzyme kinetics developed by Michaelis and Menten, and recent work extending kinetics for enzyme-catalyzed reactions in organic solvents. Based on kinetic studies of the transesterification of vinyl methacrylate (VMA) with 2-hydroxyethyl acrylate (HEA) catalyzed by Candida antarctica lipase B (CALB), a new model is proposed that resembles the kinetic model of controlled/living polymerizations governed by dynamic equilibrium of active and dormant species. Experimental data indicates that by judicious selection of reaction conditions steady-state conditions can be achieved and very clean products with quantitative conversion can be produced. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-12T18:01:11.775139-05:
      DOI: 10.1002/aic.15544
  • An optimization-based approach for structural design of self-assembled DNA
    • Authors: Yu Gao; Yongli Mi, Richard Lakerveld
      Abstract: DNA tiles are self-assembled nanostructures, which offer exciting opportunities for synthesis of novel materials. A challenge for structural design of DNA tiles is to identify optimal locations for so-called crossovers, which are bridges between DNA double helices formed by pairs of single-stranded DNA. An optimization-based approach is presented to identify optimal locations for such crossovers. Minimization of a potential-energy model for a given structural design demonstrates the importance of local minima. Both deterministic global optimization of a reduced model and multi-start optimization of the full model are applied successfully to identify the global minimum. MINLP optimization using a branch-and-bound algorithm (GAMS/SBB) identifies an optimal structural design of a DNA tile successfully with significant reduction in computational load compared to exhaustive enumeration, which demonstrates the potential of the proposed method to reduce trial-and-error efforts for structural design of DNA tiles. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-12T18:01:09.366887-05:
      DOI: 10.1002/aic.15546
  • Surface Wettability Effect on Fluid Transport in Nanoscale Slit Pores
    • Authors: Shuangliang Zhao; Yaofeng Hu, Xiaochen Yu, Yu Liu, Zhi-Shan Bai, Honglai Liu
      Abstract: The surface wettability effect on fluid transport in nanoscale slit pores is quantitatively accessed by using non-equilibrium molecular dynamics (NEMD) simulation incorporating with density functional theory (DFT). In particular, the slip lengths of benzene steady flows under various wetting conditions are computed with NEMD simulations and a quasi-general expression is given, while the structural properties are investigated with DFT. By taking into account the inhomogeneity of fluid density inside pore, we find that the conventional flux enhancement rate is associated with both the molecule slipping and geometrical confinement, and it becomes drastically high in solvophobic pores especially when the pore size is of several fluid diameters. In good agreement with experimental results, we further show that the wettability effect competes with pore size effect in determining the flux after pore inner surface modification, and a high flux can be achieved when the deposited layer is solvophobic yet thin. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-12T09:35:29.514283-05:
      DOI: 10.1002/aic.15535
  • Effect of Particle Shape on Fluid Flow and Heat Transfer for Methane Steam
           Reforming Reactions in a Packed Bed
    • Authors: Karthik G. M; Vivek V. Buwa
      Abstract: Numerical simulations of a cylindrical packed bed with tube to particle diameter ratio of 1.4, containing 10 particles were performed to understand the effect of particle shapes on pressure drop, heat transfer and reaction performance. Six particle shapes viz. cylinder as the reference, trilobe and daisy having external shaping, hollow cylinder, cylcut and 7-hole cylinder including internal voids were chosen. Methane steam reforming (MSR) reactions were considered for the heat transfer and reaction performance evaluation. The present study showed that the external shaping of particles offered lower pressure drop, but lower values of effectiveness factor indicating strong diffusion limitations. The internally shaped particles offered increased surface area, led to higher effectiveness factor and allowed to overcome the diffusion limitations. The effective heat transfer and effectiveness factor of the trilobe shaped particle per unit pressure drop was found to be the best among the particle shapes considered in the present work. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-11T10:46:19.653649-05:
      DOI: 10.1002/aic.15542
  • Triboelectric charging of monodisperse particles in fluidized beds
    • Authors: Jari Kolehmainen; Ali Ozel, Christopher M. Boyce, Sankaran Sundaresan
      Abstract: To investigate the interplay between particle charging and hydrodynamics in fluidized beds, models for triboelectric charging and electrostatic forces were built into a CFD-DEM model. Charge transfer was governed by the difference in effective work function between contacting materials as well as the electric field at the point of contact. Monodisperse particles were fluidized with an effective work function difference between the particles and the conducting walls. For smaller work function differences, hydrodynamics were not changed significantly as compared to an uncharged case. In these simulations, the average charge saturated at a value much lower than the value anticipated based on the work function difference, and a unimodal distribution of charges was observed. For larger work function differences, particles stuck to walls and bed height oscillations due to slugging were less pronounced. For these cases, a bimodal distribution of charges emerged due to effects from strong electric fields. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-07T19:25:54.940901-05:
      DOI: 10.1002/aic.15541
  • Determination of mass transfer resistances of fast reactions in
           three-phase mechanically agitated slurry reactors
    • Authors: Ilias K. Stamatiou; Frans L. Muller
      PubDate: 2016-10-07T19:25:51.264114-05:
      DOI: 10.1002/aic.15540
  • Hydrogen bond lifetimes and statistics of aqueous mono-,di- and tri-
           ethylene glycol
    • Authors: Richard Olsen; Bjørn Kvamme, Tatiana Kuznetsova
      Abstract: Hydrogen bond statistics, energy distributions of hydrogen bonds and hydrogen bond lifetimes for aqueous monoethylene glycol (MEG), diethylene glycol (DEG) and triethylene glycol (TEG) were investigated at temperatures ranging from 275 to 370K at 101.325kPa using molecular dynamics simulations. Each individual type of hydrogen bond were studied separately to better understand how each type of hydrogen bond affected the collective behavior often measured in experiments. We also studied the effects of glycols on water-water hydrogen bond structures and lifetimes. Decay constants for hydroxyl type hydrogen bonds, as well as for water based hydrogen bonds were in the same order, thus indicating that all these hydrogen bonds play an essential role in the process of dielectric relaxation. Correlations between water hydrogen bond distances and angles were not affected markedly by adding glycols. However, hydrogen bond lifetimes increased by 9, 29 and 62 times by adding MEG, DEG and TEG, respectively. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-07T19:25:45.951097-05:
      DOI: 10.1002/aic.15539
  • Capturing the Non-spherical Shape of Granular Media and Its Trickle Flow
           Characteristics Using Fully-Lagrangian Method
    • Authors: Shungo Natsui; Hifumi Takai, Ryota Nashimoto, Ko-ichiro Ohno, Sohei Sukenaga, Tatsuya Kikuchi, Ryosuke O. Suzuki
      Abstract: We performed a numerical analysis for simulating granular media structures containing non-spherical elements and the liquid trickle flow characteristics of such structures. Fully-Lagrangian numerical simulation methods can track all motion information for solid or liquid elements at each point in time. We introduced suitable compressibility to MPS and performed individual packing behavior calculations for non-spherical elements, based on DEM with expanded functions. RB-DEM is a method using a DEM contact force model that is expanded to handle the motion of freely shaped rigid bodies. It expresses complex shapes to enable low calculation costs and intuitive mounting. We used the boundary for the granular media configured with non-spherical elements to implement a trickle flow simulation based on WC-MPS. Even for elements of equal volume, different shapes changed the liquid passage velocity and hold-up amount. The mean downflow velocity of the liquid phase was not always dependent on the void fraction. For the plane of projection, we obtained a good correlation with the mean downflow velocity in each packed structure, and successfully performed arrangements according to the new liquid-passage shape coefficient. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-05T18:15:57.108509-05:
      DOI: 10.1002/aic.15538
  • Bubble/droplet formation and mass transfer during gas-liquid-liquid
           segmented flow with soluble gas in a microchannel
    • Authors: Chaoqun Yao; Yanyan Liu, Shuainan Zhao, Zhengya Dong, Guangwen Chen
      Abstract: Microchannels have great potential in intensification of gas-liquid-liquid reactions involving reacting gases, such hydrogenation. This work uses CO2-octane-water system to model the hydrodynamics and mass transfer of such systems in a microchannel with double T-junctions. Segmented flows are generated with three inlet sequences and the size laws of dispersed phases are obtained. Three generation mechanisms of dispersed gas bubbles/water droplets are identified: squeezing by the oil phase, cutting by the droplet/bubble, cutting by the water-oil/gas-oil interface. Based on the gas dissolution rate, the mass transfer coefficients are calculated. It is found that water droplet can significantly enhance the transfer of CO2 into the oil phase initially. When bubble-droplet cluster are formed downstream the microchannel, droplet will retard the mass transfer. Other characteristics such as phase hold-up, bubble velocity and bubble dissolution rate are also discussed. The information is beneficial for microreactor design when applying three-phase reactions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-05T10:20:54.479154-05:
      DOI: 10.1002/aic.15536
  • Partial slip boundary conditions for collisional granular flows at flat
           frictional walls
    • Authors: L. (Lei) Yang; J.T. (Johan) Padding, J.A.M. (Hans) Kuipers
      Abstract: We derive new boundary conditions (BCs) for collisional granular flows of spheres at flat frictional walls. A new theory is proposed for the solids stress tensor, translational and rotational energy dissipation rate per unit area and fluxes of translational and rotational fluctuation energy. In the theory we distinguish between sliding and sticking collisions and include particle rotation. The predictions are compared with literature results obtained from a discrete particle model evaluated at a given ratio of rotational to translational granular temperature. We find that the new theory is in better agreement with the observed stress ratios and heat fluxes than previous kinetic theory predictions. Finally, we carry out two fluid model simulations of a bubbling fluidized bed with the new BCs, and compare the simulation results with those obtained from discrete particle simulations. The comparison reveals that the new BCs are better capable of predicting solids axial velocity profiles, solids distribution near the walls and granular temperatures. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-04T18:31:14.679169-05:
      DOI: 10.1002/aic.15534
  • Integration of Biofuels Intermediates Production and Nutrients Recycling
           in the Processing of a Marine Algae
    • Authors: Ali Teymouri; Elena Barbera, Eleonora Sforza, Tomas Morosinotto, Alberto Bertucco, Sandeep Kumar
      Abstract: The cost-effective production of liquid biofuels from microalgae is limited by several factors such as recovery of the lipid fractions as well as nutrients management. Flash hydrolysis (FH), a rapid hydrothermal process, has been successfully applied to fractionate the microalgal biomass into solid biofuels intermediates while recovering a large amount of the nutrients in the aqueous phase (hydrolyzate) in a continuous flow reactor. The aim of the work is to enhance the quality of a high-ash containing marine algae Nannochloropsis gaditana as biofuel feedstock while recycling nutrients directly for algae cultivation. Characterization of products demonstrated an increase in extractable lipids from 33.5 to 65.5 wt% (dry basis) while retaining the same FAME profile, in addition to diminution of more than 70 wt% of ash compared to raw microalgae. Moreover, the hydrolyzate was directly used to grow a microalga of the same genus. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-04T18:31:10.900887-05:
      DOI: 10.1002/aic.15537
  • Issue information
    • Abstract: Cover illustration. On the left is a schematic ternary alloy composition map. In the middle top is a composition spread alloy film containing Fe, Ni and Al. In the middle bottom the sample has been oxidized in air at 700 K, showing composition dependent oxidation behavior. On the right is a ternary map of the oxygen uptake across the composition space. (Cover art adapted from Matthew A. Payne, James B. Miller, Andrew J. Gellman, Corrosion Science, 91, 46-57, (2015). 10.1002/aic.15294
      PubDate: 2016-10-04T09:42:55.338402-05:
      DOI: 10.1002/aic.15001
  • On near-wall jets in a disc-like Gas Vortex Unit
    • Authors: Kaustav Niyogi; Maria Torregrosa, Maria N. Pantzali, Vladimir N. Shtern, Geraldine J. Heynderickx, Guy B. Marin
      Abstract: To clarify the three-dimensional structure of near-wall jets observed in disc-like gas vortex units, experimental and numerical studies are performed. The experimental results are obtained using Particle Image Velocimetry (PIV), Laser Doppler Anemometry (LDA), pressure probes and surface oil flow visualization techniques. The first three techniques have been used to investigate the bulk flow hydrodynamics of the vortex unit. Surface oil flow visualization is adopted to visualize streamlines near the end-walls of the vortex unit. The surface streamlines help determine the azimuthal and radial velocity components of the radial near-wall jets. Simulations of the vortex unit using FLUENT® v.14a are simultaneously performed, computationally resolving the near-wall jet regions in the axial direction. The simulation results together with the surface oil flow visualization establish the three-dimensional structure of the near-wall jets in gas vortex units for the first time in literature. It is also conjectured that the near-wall jets develop due to combined effects of bulk flow acceleration and swirl. The centrifugal force diminishes in the vicinity of the end-walls. The radially inward pressure gradient in these regions, no longer balanced by the centrifugal force, pushes gas radially inward thus developing the near-wall jets. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-04T03:31:20.558569-05:
      DOI: 10.1002/aic.15533
  • A fractal model for real gas transport in porous shale
    • Authors: Lidong Geng; Gensheng Li, Shouceng Tian, Mao Sheng, Wenxi Ren, Pacelli Zitha
      Abstract: A model for real gas flow in shale gas matrices is proposed and consists of two main steps: (a) developing a microscopic (single pore) model for a real gas flow by generalizing our previously reported Extended Navier-Stokes Equations (ENSE) method and (b) by using fractal theory concepts, up-scaling the single pore model to the macroscopic scale. A prominent feature of the up-scaled model is a predictor for the apparent permeability (AP). Both models are successfully validated with experimental data. The impact of the deviation of the gas behavior from ideality (real gas effect) on the gas transport mechanisms is investigated. The effect of the structural parameters (porosity Ф, the maximum pore diameter Dmax, and the minimum pore diameter Dmin) of the shale matrix on the apparent permeability is studied and a sensitivity analysis is performed to evaluate the significance of the parameters for gas transport. We find that (1) the real gas transport models for a single pore and porous shale matrix are both reliable and reasonable; (2) the real gas effect affects the thermodynamic parameters of the free gas and the adsorption and transport capacity of the adsorbed gas; (3) the real gas effect decreases the effective permeability for convective flow and surface diffusion; i.e., the derivation degree of the effective permeability for bulk diffusion and Knudsen diffusion increases with increasing pressure but presents a bathtub shape when the pore diameter is smaller than 10 nm; and (4) the apparent permeability increases with Ф, Dmax, and Dmin. It is more sensitive to Dmax, followed by the porosity. Dmin has a minor impact. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-10-02T16:55:34.030844-05:
      DOI: 10.1002/aic.15516
  • Cyclic mass transport phenomena in a novel reactor for gas-liquid-solid
    • Authors: M. G. Gelhausen; S. Yang, M. Cegla, D. W. Agar
      Abstract: This study introduces a novel reactor concept, referred to as the Siphon Reactor, for intensified phase contacting of gas-liquid reactants on heterogeneous catalysts. The reactor comprises a fixed catalyst bed in a siphoned reservoir, which is periodically filled and emptied. This serves to alternate liquid-solid and then gas-liquid mass transfer processes. As the duration of each phase can be manipulated, mass transfer can be deliberately harmonized with the reaction. Residence time experiments demonstrate that, in contrast to periodically operated trickle-bed reactors, the static liquid hold-up is exchanged frequently and uniformly due to the complete homogeneous liquid wetting. A mathematical model describing the siphon hydrodynamics was developed and experimentally validated. The model was extended to account for a heterogeneously catalyzed gas-liquid reaction and capture the influence of siphon operation on conversion and selectivity of a consecutive reaction. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-01T03:35:48.144641-05:
      DOI: 10.1002/aic.15532
  • Minimum pickup velocity – the transition between nano-scale and
    • Authors: Aditya Anantharaman; J. Ruud van Ommen, Jia Wei Chew
      Abstract: The transport of nano-scale particles has become increasingly important, but the knowledge base available is limited. This study aims to bridge the knowledge gap between the nano- and micro-scales for pneumatic conveying. A key parameter is the minimum pickup velocity (Upu), which is the minimum fluid velocity required to initiate motion in a particle originally at rest. The Upu values of nine alumina particles with particle diameters (dp) ranging from 5 nm to 110,000 nm were determined using the weight loss method, then compared against the established pickup Zones (analogous to the Geldart Groups). Results indicated that: (i) Upu varied non-monotonically with increasing dp, thus revealing the missing link between the nano- and micro-scales; (ii) the intermediate particle diameters surprisingly did not agree with any pickup Zone; (iii) Zone III (analogous to Geldart Group C) is inadequate for all the nano-scale particles, so new boundaries and a new Zone are proposed. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-29T03:36:59.379653-05:
      DOI: 10.1002/aic.15527
  • Periodic reactive flow simulation: Proof of concept for steam cracking
    • Authors: David J. Van Cauwenberge; Laurien A. Vandewalle, Pieter A. Reyniers, Jens Floré, Kevin M. Van Geem, Guy B. Marin
      Abstract: Streamwise periodic boundary conditions (SPBCs) have been successful in reducing the computational cost of simulating high aspect ratio processes. Extending beyond the classic assumptions of constant property flows, a novel approach incorporating non-equilibrium kinetics was developed and implemented for the simulation of an industrial propane steam cracker. Comparison with non-periodic benchmarks provided validation as relative errors on the main product yields were consistently below 1% for different reactor configurations. A further order-of-magnitude reduction of the radial errors on product concentrations was obtained via an intuitive correction method based on the concept of local fluid age. The computational speedup achieved through application of SPBCs was a factor 16 to 250 compared to the non-periodic simulations. The presented methodology thus serves as a quick screening tool for the development of novel reactor designs and unlocks the potential for using more elaborate kinetic models or a more fundamental approach towards turbulence modeling. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-28T09:47:07.373878-05:
      DOI: 10.1002/aic.15530
  • N-doped porous carbons for CO2 capture: Rational choice of N-containing
           polymer with high phenyl density as precursor
    • Authors: Jian-Cheng Geng; Ding-Ming Xue, Xiao-Qin Liu, Yao-Qi Shi, Lin-Bing Sun
      Abstract: N-doped porous carbons (NPCs) are highly promising for CO2 capture, but their preparation is severely hindered by two factors, namely, the high cost of N-containing polymer precursors and the low yield of carbon products. Here we report for the first time the fabrication of NPCs through the rational choice of the polymer NUT-4, with low cost and high phenyl density, as precursor. For the material NPC-600 obtained from carbonization at 600°C, the yield is as high as 52.1%. The adsorption capacity of CO2 on NPC-600 reaches 6.9 mmol/g at 273 K and 1 bar, which is obviously higher than that on the benchmarks, including 13X zeolite (4.1 mmol/g) and activated carbon (2.8 mmol/g), as well as most reported carbon materials. Our results also demonstrate that the present NPCs can be completely regenerated under mild conditions. The abundant microporosity and “CO2-philic” (N-doped) sites are responsible for the adsorption performance. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-28T09:47:03.728678-05:
      DOI: 10.1002/aic.15531
  • Continuous fractionation of multicomponent mixtures with sequential
           centrifugal partition chromatography
    • Authors: Johannes Goll; Mirjana Minceva
      Abstract: The applicability of sequential centrifugal partition chromatography for continuous fractionation of multicomponent mixtures, represented here by a mixture of four parabens with very similar molecular structure, was studied. The fractionation of the quaternary feed mixture was regarded as a separation of a pseudo-binary mixture.The model-based approach was used to select the biphasic liquid system and the unit operating parameters. All desired fractions were recovered with purities > 99%.The influence of the solute concentration on the density, viscosity and volume ratio of the phases as well as on the partitioning of the solutes between the two phases was investigated. According to these results, possibilities for increasing the throughput were proposed and validated experimentally. For example, butyl paraben with a purity ≥ 99% was continuously separated from the rest of the parabens in a 250 ml unit with a throughput of 3.24 g h−1 and a solvent consumption of 0.33 l g−1. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-28T09:41:09.068941-05:
      DOI: 10.1002/aic.15529
  • Correction of Wall Adhesion Effects in the Centrifugal Compression of
           Strong Colloidal Gels
    • Authors: Richard Buscall; Daniel R Lester
      PubDate: 2016-09-28T09:36:12.565022-05:
      DOI: 10.1002/aic.15528
  • Three‐Dimensional Modelling of Porosity Development during the
           Gasification of a Char Particle
    • Authors: Kay Wittig; Petr Nikrityuk, Sebastian Schulze, Andreas Richter
      Abstract: This work is devoted to the three‐dimensional, direct modelling of porosity and specific surface development during the gasification of a char particle. The model was developed for heterogeneous reactions occurring inside a char particle in a kinetically controlled regime. The main goal of this work is to analyse the impact of different pore size distributions on the particle carbon conversion rate. In particular, it is shown that under certain conditions the outer particle surface can influence the specific surface area. In this context the possible adaptation of the parameter ψ from the random pore model developed by Bhatia and Perlmutter (AIChE J 26, p. 379–386, 1980) is explained. The results of simulations are compared against the random pore model and discussed. Additionally, based on the results of simulations, the physics behind several input parameters used by the random pore model are explored. Finally, the possible fragmentation of a chemically reacting char particle during its gasification in dependence of instantaneous porosity was investigated numerically. It was shown that the earliest fragmentation occurs at a carbon conversion of about 0.5 to 0.6 due to the disaggregation of the pore walls. The results are discussed and compared implicitly with data published in the literature. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-27T17:41:22.910987-05:
      DOI: 10.1002/aic.15526
  • Absorption of Picoliter Droplets by Thin Porous Substrates
    • Authors: Hua Tan
      Abstract: Absorption of picoliter (pL) droplets into porous substrates is studied experimentally and numerically. In the case of pL droplets, major phenomena involved in the interaction between droplet and porous media develop at different time scales: spreading and wetting at microseconds, absorption and wicking at milliseconds, and evaporation at seconds. Therefore, one can decouple these processes to minimize the complexity of the study. A high‐speed imaging system capable of 1 million frames per second is used to visualize individual droplets impacting, spreading, and imbibing on substrates. To simulate droplet dynamics, the governing equations for flow outside and inside porous media are proposed and solved using an in‐house developed computational fluid dynamics (CFD) solver. The simulation results are in good agreement with the experimental data. The effect of drop impact velocity and fluid properties on final dot shape in the porous substrates is investigated through a series of parametric numerical studies. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-27T17:41:06.274527-05:
      DOI: 10.1002/aic.15525
  • Hydrocarbon Steam Reforming Using Silicalite‐1 Zeolite Encapsulated
           Ni‐Based Catalyst
    • Authors: Ummuhan Cimenler; Babu Joseph, John N. Kuhn
      Abstract: A Silicalite‐1 zeolite membrane encapsulated 1.6wt%Ni‐1.2wt%Mg/Ce0.6Zr0.4O2 steam reforming composite catalyst synthesized by a physical coating method was used to investigate effect of encapsulation on size selective steam reforming, using methane (CH4) and toluene (C7H8) as representative species. Characterization methods (Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Physisorption Analysis, and X‐ray Diffraction (XRD)) were used to analyze pre‐ and post‐reaction samples. SEM, EDS and XRD analyses showed that Silicalite‐1 was coated successfully onto the core catalyst. Weisz‐Prater Criteria and Thiele moduli calculations indicated internal diffusion limitations. Combined reforming of CH4 and C7H8 at 800°C on the composite catalyst demonstrated stability during the 10 h time on stream while the uncoated SR catalyst deactivated. The non‐acidic Silicalite‐1 encapsulated catalyst showed decreases (∼2‐7%) in both CH4 and C7H8 conversions compared to acidic H‐β zeolite confirming that shell acidity did contribute to conversion and suggested that shell defects/grain boundaries were responsible for the C7H8 conversion. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T18:11:10.178664-05:
      DOI: 10.1002/aic.15521
  • Large‐Scale Heat Exchanger Networks Synthesis using Simulated Annealing
           and the novel Rocket Fireworks Optimization
    • Authors: Leandro Vitor Pavão; Caliane Bastos Borba Costa, Laureano Jiménez, Mauro Antonio da Silva Sá Ravagnani
      Abstract: Heat Exchanger Network (HEN) synthesis is an important field of study in process engineering. However, obtaining optimal HEN design is a complex task. When mathematically formulated, it may require sophisticated methods to achieve good solutions. The complexity increases even more for large‐scale HEN. In this work, a hybrid meta‐heuristic method is presented. A rather simple Simulated Annealing approach is used for the combinatorial level, while a strategy named Rocket Fireworks Optimization is developed and applied to the continuous domain. An advantage over other approaches is that the algorithm was written in C++, which is free and faster when compared to many other languages. The developed method was able to provide the lowest costs solutions reported so far to six cases well studied in the literature. An important feature of the approach here proposed is that, differently from other approaches, it does not split HEN into smaller problems during the optimization. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T18:11:06.773893-05:
      DOI: 10.1002/aic.15524
  • Pinch‐based Shortcut Method for the Conceptual Design of Isothermal
           Extraction Columns
    • Authors: Christian Redepenning; Sebastian Recker, Wolfgang Marquardt
      Abstract: Shortcut methods are valuable tools for a comprehensive evaluation of key performance indicators in the early phase of conceptual process design. For the design of extraction columns, operation at minimum solvent demand represents a thermodynamically sound indicator, which is, however, difficult to determine. The suggested shortcut model therefore exploits the existence of the pinch point to directly identify operation at minimum solvent demand. It is solved quickly and reliably by a step‐by‐step procedure. The final step allows a reduction of the approximation error to any desired degree of accuracy. No simplifications regarding the number of components in the mixture or its thermodynamic behavior are introduced. Hence, arbitrary mixtures can be tackled. The performance of the method is highlighted by a fully automated screening of thousands of solvents for the recovery of fermentation products acetone, 1‐butanol, and ethanol from aqueous solution. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T18:06:29.156423-05:
      DOI: 10.1002/aic.15523
  • A Packed‐Bed Solar Reactor for the Carbothermal Zinc Production –
           Dynamic Modelling and Experimental Validation
    • Authors: N. Tzouganatos; C. Wieckert, A. Steinfeld
      Abstract: Integration of concentrated solar energy into the pyrometallurgical Zn production process as clean source of high‐temperature process heat could significantly reduce fossil fuels consumption and its concomitant CO2 emissions. The solar‐driven carbothermal reduction of ZnO is investigated using a 10‐kWth solar reactor featuring two cavities, the upper one serving as the solar absorber and the lower one containing a packed‐bed of ZnO and beech charcoal as the biogenic reducing agent. Experimentation in a high‐flux solar simulator is carried out under radiative fluxes of 2300 – 2890 suns, yielding a peak solar‐to‐chemical energy conversion efficiency of 18.4%. The reactor performance under variable operating conditions is analysed via a dynamic numerical model coupling heat transfer with chemical kinetics. The model is validated by comparison to the experimental data obtained with the 10‐kWth packed‐bed solar reactor and further applied to predict the effect of incorporating semi‐continuous feeding of reactants on the process efficiency. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T18:06:22.845143-05:
      DOI: 10.1002/aic.15522
  • Investigating dry reforming of methane with spatial reactor profiles and
           particle‐resolved CFD simulations†
    • Authors: Gregor D. Wehinger; Matthias Kraume, Viktor Berg, Oliver Korup, Katharina Mette, Robert Schlögl, Malte Behrens, Raimund Horn
      Abstract: Dry reforming of methane (DRM) over nickel in a fixed‐bed reactor of spheres was studied experimentally and with CFD simulations. Temperature and mole fraction profiles were measured in a dedicated profile reactor as function of axial coordinate. Particle‐resolved CFD simulations took into account conjugate heat transfer, surface‐to‐surface radiation, and surface reactions described by microkinetics. Energy transport of CFD simulations were verified by studying heat transfer without chemical reactions. DRM experiments could not be reproduced with the original microkinetics formulation, even with the axial temperature profile applied. A detailed analysis of the microkinetics showed that thermodynamic inconsistencies are present, which are amplified by high surface coverage of CO*. After modifying the mechanism the experiments could be reproduced. This study shows how complex interactions between local transport phenomena and local kinetics can be quantified without relying on transport correlations. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T10:15:28.585484-05:
      DOI: 10.1002/aic.15520
  • Mechanistic Insights into Aqueous Phase Propanol Dehydration in
           H‐ZSM‐5 Zeolite
    • Authors: Donghai Mei; Johannes A. Lercher
      Abstract: Aqueous phase dehydration of 1‐propanol over H‐ZSM‐5 zeolite was investigated using density functional theory (DFT) calculations. The water molecules in the zeolite pores prefer to aggregate via the hydrogen bonding network and be protonated at the Brønsted acidic sites (BAS). Two typical configurations, i.e., dispersed and clustered, of water molecules were identified by ab initio molecular dynamics simulations of the mimicking aqueous phase H‐ZSM‐5 unit cell with 20 water molecules per unit cell. DFT calculated Gibbs free energies suggest that the dimeric propanol‐propanol, the propanol‐water, and the trimeric propanol‐propanol‐water complexes are formed at high propanol concentrations in aqueous phase, which provide a kinetically feasible dehydration reaction channel of 1‐propanol to propene. The calculation results indicate that the propanol dehydration via the unimolecular mechanism becomes kinetically discouraged due to the enhanced stability of the protonated dimeric propanol and the protonated water cluster acting as the BAS site for alcohol dehydration. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T10:15:23.019629-05:
      DOI: 10.1002/aic.15517
  • Performance of Combined Use of Chlorosilanes and AlCl3 in the
           Carboxylation of Toluene with CO2
    • Authors: Xibao Zhang; Zhenmin Cheng
      Abstract: Carboxylation of toluene with CO2 for the production of p‐toluic acid was shown to be promoted by the addition of Me2PhSiCl, Ph2SiCl2, Ph3SiH or Ph3SiCl into the AlCl3 activated system, and the reaction activity was in the increasing order of Ph2SiCl2 
      PubDate: 2016-09-26T10:15:20.572432-05:
      DOI: 10.1002/aic.15519
  • Enhancing co‐production of H2 and syngas via water splitting and POM on
           surface‐modified oxygen permeable membranes1
    • Authors: Xiao‐Yu Wu; Mruthunjaya Uddi, Ahmed F. Ghoniem
      Abstract: In this paper, we report a detailed study on co‐production of H2 and syngas on La0.9Ca0.1FeO3‐δ (LCF‐91) membranes via water splitting and partial oxidation of methane (POM), respectively. A permeation model shows that the surface reaction on the sweep side is the rate limiting step for this process on a 0.9 mm‐thick dense membrane at 990oC. Hence, sweep side surface modifications such as adding a porous layer and nickel catalysts were applied; the hydrogen production rate from water thermolysis is enhanced by two orders of magnitude to 0.37 μmol/cm2•s compared with the results on the unmodified membrane. At the sweep side exit, syngas (H2/CO = 2) is produced and negligible solid carbon is found. Yet near the membrane surface on the sweep side, methane can decompose into solid carbon and hydrogen at the surface, or it may be oxidized into CO and CO2, depending on the oxygen permeation flux. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T10:10:23.467095-05:
      DOI: 10.1002/aic.15518
  • A New and original microwave continuous reactor under high pressure for
           future chemistry
    • Authors: I. Polaert; L. Estel, D. Luart, C. Len, M. Delmotte
      Abstract: A new and original high pressure reactor has been designed and developed for continuous flow chemistry under microwaves at industrial scale. The reactor originality is that the microwave applicator is the reactor itself. It allows then the use of metallic and thick walls for the reactor adapted to a use at high pressures and high temperatures. Wave propagation coupled to heat transfer was simulated using COMSOL Multiphysics® and the design was optimized in order to minimize wave reflections and maximize energy transfers in the reacting medium. This leads to extremely good energy yields. Experiments confirm that the microwave energy is fully absorbed by the reacting medium. The reactor allows continuous chemical reactions at a kg/h scale, under microwave heating, up to 7 MPa and 200°C. The double dehydration of hexylene glycol has been performed under various operating conditions demonstrating then the operability of this new reactor. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T04:00:43.30936-05:0
      DOI: 10.1002/aic.15515
  • Mechanism of the effects of microwave irradiation on the relative
           volatility of binary mixtures
    • Authors: Hong Li; Junjie Cui, Jiahui Liu, Xingang Li, Xin Gao
      Abstract: The use of microwave irradiation to enhance distillation processes has been reported recently. However, there is an ongoing debate in the scientific community on whether the observed enhancement is mainly a consequence of the shift of the “equilibrium” of vapor‐liquid mass transfer. In this paper, a developed instrument was used to determine the relative volatility of various binary mixtures under microwave irradiation. By comparing the relative volatility in the presence/absence of microwave irradiation, the shift of the “equilibrium” of vapor‐liquid mass transfer was observed for certain binary mixtures under microwave irradiation. The effects of microwave irradiation on the relative volatility of binary mixtures (in addition to the mechanisms involved therein) were analyzed using the non‐equilibrium thermodynamic principle. The results demonstrate that differences in the dielectric properties, microwave field intensity, intermolecular forces, and boiling point play dominant roles in determining the effects of microwaves on the relative volatility. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-22T18:15:27.600831-05:
      DOI: 10.1002/aic.15513
  • Particle Entrainment from Gas‐Solid Fluidized Beds: Conductive vs.
           Dielectric Fines
    • Authors: Farzam Fotovat; John R. Grace, Xiaotao T. Bi
      Abstract: Conductive and non‐conductive fine powders were entrained by air at atmospheric temperature and pressure in a fluidization column of diameter 0.15 m made of stainless steel. Under equivalent operating conditions, entrainment of the conductive particles was markedly higher than for non‐conductive species. This finding cannot be explained by hydrodynamic factors. Examining the electrostatic interaction between touching particles reveals that dominance of the inter‐particle attractive forces hinders independent motion of non‐conductive particles in the freeboard. In addition, because of non‐uniform distribution of the electrical charges over the surface of dielectric particles, they are subject to stronger electrostatic forces than for particles made of conductive materials. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-22T18:15:23.344629-05:
      DOI: 10.1002/aic.15514
  • Mathematical modelling and experimental validation of a novel periodic
           flow crystallization using MSMPR crystallizers
    • Authors: Qinglin Su; Keddon A. Powell, Chris D. Rielly, Zoltan K. Nagy
      Abstract: The challenges of insufficient residence time for crystal growing and transfer line blockage in conventional continuous MSMPR operations are still not well addressed. Periodic flow crystallization is a novel method whereby controlled periodic disruptions are applied to the inlet and outlet flows of an MSMPR crystallizer in order to increase its residence time. A dynamic model of residence time distribution in an MSMPR crystallizer was first developed to demonstrate the periodic flow operation. Besides, process models of periodic flow crystallizations were developed with an aim to provide a better understanding and improve the performance of the periodic flow operation, wherein the crystallization mechanisms and kinetics of the glycine‐water system were estimated from batch cooling crystallization experiments. Experiments of periodic flow crystallizations were also conducted in single‐/three‐stage MSMPR crystallizers to validate the process models and demonstrate the advantages of using periodic flow operation in MSMPR stages. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-22T10:25:22.155663-05:
      DOI: 10.1002/aic.15510
  • Preparation of Thin Film Nanocomposite Membranes with Surface Modified MOF
           for High Flux Organic Solvent Nanofiltration
    • Authors: Xiangyu Guo; Dahuan Liu, Tongtong Han, Hongliang Huang, Qingyuan Yang, Chongli Zhong
      Abstract: Preparation of defect‐free and optimized thin film nanocomposite (TFN) membranes is an effective way to enhance the process of organic solvent nanofiltration. However, it still remains a great challenge due to poor filler particle dispersibility in organic phase and compatible issue between fillers and polymers. Aiming at these difficulties, UiO‐66‐NH2 nanoparticles were surface modified with long alkyl chains and used in the preparation of TFN membranes. As a result, defect‐free TFN membranes with ultrathin MOF@polyamide layer were successfully prepared benefited from the improved particle dispersibility in n‐hexane. Significant enhancement was found in methanol permeance after nanoparticle incorporation, without comprising the tetracycline rejection evidently. Especially, the novel TFN membrane prepared with organic phase solution containing 0.15% (w/v) modified UiO‐66‐NH2 nanoparticles showed a superior methanol permeance of 20 L·m−2·h−1·bar−1 and a tetracycline rejection of about 99%, which is appealing to the application in pharmaceutical industry for example. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-22T10:10:40.923949-05:
      DOI: 10.1002/aic.15508
  • Water Content of Light n‐Alkanes: New Measurements and
           Cubic‐Plus‐Association Equation of State Modelling
    • Authors: Mohsen Zirrahi; Hassan Hassanzadeh, Jalal Abedi
      Abstract: Light hydrocarbon gases such as methane, ethane, propane, and butane or other so called gaseous solvents have been suggested as steam additives to improve bitumen recovery and energy efficiency. The water content of these gases is one of the key requirements in the simulation and design of solvent‐aided thermal heavy oil recovery processes. In this work, we present new experimental data for the water content of these gases at high temperatures (up to 493.15 K) and moderate pressures (P 
      PubDate: 2016-09-22T10:10:36.194183-05:
      DOI: 10.1002/aic.15512
  • Input‐output Pairing Accounting for Both Structure and Strength in
    • Authors: Xunyuan Yin; Jinfeng Liua
      Abstract: Input‐output pairing is an important problem in control system design and is often performed using the relative gain array (RGA) based approaches. While RGA‐based approaches have been very successful in many applications, they have some well‐known limitations. For example, they may give results which are not consistent with the physical topology since only the strength of interaction between inputs and outputs is taken into account in the RGA. In this work, we propose a new measure for input‐output pairing that explores both strength and structural information in input‐output coupling. Specifically, we take advantage of the tool of relative degree to measure the physical closeness of input‐output pairs and to explore the strength of interaction progressively with respect to the relative degree. We call the proposed measure relative sensitivity array (RSA) between inputs and outputs. Detailed analysis is performed to reveal the relationship between the gain matrix used in the RGA and the sensitivity matrix in the RSA from a mathematical point of view. Since the RSA is an analog of the RGA, many existing pairing guidelines developed for the RGA can be used in the proposed RSA‐based pairing. The proposed RSA‐based approach is applied to two examples. The results show that pairs formed by the proposed approach are consistent with the physical topologies of the processes. Also, the results show that the proposed approach can handle larger systems that cannot be effectively handled by RGA‐based approaches. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-22T10:05:28.847603-05:
      DOI: 10.1002/aic.15511
  • An approach for drag correction based on the local heterogeneity for
           gas‐solid flows
    • Authors: Tingwen Li; Limin Wang, William Rogers, Guofeng Zhou, Wei Ge
      Abstract: The drag models typically used for gas‐solids interaction are mainly developed based on homogeneous systems of flow passing fixed particle assembly. It has been shown that the heterogeneous structures, i.e. clusters and bubbles in fluidized beds, need to be resolved to account for their effect in the numerical simulations. Since the heterogeneity is essentially captured through the local concentration gradient in the computational cells, the present study proposes a simple approach to account for the non‐uniformity of solids spatial distribution inside a computational cell and its effect on the interaction between gas and solid phases. To validate this approach, the predicted drag coefficient has been compared to the results from direct numerical simulations. In addition, the need to account for this type of heterogeneity is discussed for a periodic riser flow simulation with highly resolved numerical grids and the impact of the proposed correction for drag is demonstrated. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-22T10:05:27.756508-05:
      DOI: 10.1002/aic.15507
  • Thermodynamic equilibrium solutions through a modified Newton Raphson
    • Authors: M. Marinoni; J. Carrayrou, Y. Lucas, P. Ackerer
      Abstract: In numerical codes for reactive transport modeling, systems of nonlinear chemical equations are often solved through the Newton Raphson method (NR). NR is an iterative procedure that results in a sequential solution of linear systems. The algorithm is known for its effectiveness in the vicinity of the solution but also for its lack of robustness otherwise. Therefore, inaccurate initial conditions can lead to non‐convergence or excessive numbers of iterations, which significantly increase the computational cost. In this work, we show that inaccurate initial conditions can lead to very ill‐conditioned system matrices, which makes NR inefficient. This efficiency is improved by preconditioning techniques and/or by coupling the NR method with a zero‐order method called the Positive Continuous Fraction (PCF) method. Numerical experiments that are based on 7 different test cases show that the ill‐conditioned linear systems within NR represent a problem and that coupling NR with a method that bypasses the computation of the Jacobian matrix significantly improves the robustness and efficiency of the algorithm. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-22T10:05:25.590484-05:
      DOI: 10.1002/aic.15506
  • Controlling three dimensional ice template via two dimensional surface
    • Authors: Miao Yang; Tuck‐Whye Wong, Jingjun Wu, Hao Bai, Tao Xie, Qian Zhao
      Abstract: Directional freezing is a fast, scalable, and environmental friendly technique for fabricating monoliths with long‐range oriented pores, which can be applied towards a wide variety of materials. However, the pore size is typically larger than 20 μm and cannot be spatially controlled, which prevent the technique from being used more widely. In this work, effect of wettability of the freezing substrate on the pore size of monolithic PEG cryogels is studied. Smaller pores can be generated via more hydrophilic substrates, and tubular pores smaller 5 μm can be created using a poly(vinyl alcohol) coated copper substrate. A numerical fitting between water contact angle of the substrates and pore size is then obtained. Moreover, pore size can be locally varied duplicating wetting patterns of the substrates. The concept of using two dimensional patterns to build monoliths with three dimensional microstructures can probably be extended to other material systems. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-22T10:05:23.386955-05:
      DOI: 10.1002/aic.15509
  • Optimization of Large‐Scale Water Transfer Networks: Conic Integer
           Programming Model and Distributed Parallel Algorithms
    • Authors: Li‐Juan Li; Rui‐Jie Zhou
      Abstract: We address in this paper the optimization of a multi‐echelon water transfer network and the associate transportation and inventory systems with demand uncertainty. Optimal network structure, facility locations, operation capacities, as well as the inventory and transportation decisions can be simultaneously determined by the MINLP model which includes bilinear, square root and nonlinear fractional terms. By exploiting the properties of this model, we reformulate the MINLP problem as a conic integer optimization model. To overcome the memory and computing bandwidth limitations caused by the huge number of active nodes in the branch‐and‐bound search tree, novel distributed parallel optimization algorithms based on Lagrangean relaxation and message passing interface as well as their serial versions are proposed to solve the resulting conic integer programming model. A regional water transfer network in China is studied to demonstrate the applicability of the proposed model and the performance of the algorithms. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-20T18:35:27.357044-05:
      DOI: 10.1002/aic.15505
  • Simultaneous Removal of NO and SO2 Using Aqueous Peroxymonosulfate with
           Coactivation of Cu2+/Fe3+ and High Temperature
    • Authors: Yangxian Liu; Yan Wang
      Abstract: A novel process on simultaneous removal of NO and SO2 using aqueous peroxymonosulfate (PMS) with synergic activation of Cu2+/Fe3+ and high temperature in an impinging stream reactor is developed for the first time. Effects of PMS concentration, Cu2+/Fe3+ concentration, reaction temperature, solution pH, flue gas flow, liquid‐gas ratio, gas components and inorganic ions on NO/SO2 removals were investigated. Active species and products were determined by electron spin resonance spectroscopy and ion chromatography. Removal pathways of NO/SO2 were revealed, and mass transfer‐reaction kinetics of NO removal was studied. The optimal experimental conditions are obtained. H2SO4 and HNO3 are the main products. It is found that there is a clear synergy between Cu2+/Fe3+ and high temperature for activating PMS. SO4·‐ and ·OH are found to be the main oxidants for NO removal. NO removals belong to pseudo‐first fast reactions in the two investigated oxidation systems. Besides, the kinetic parameters are also measured. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-16T18:05:58.57713-05:0
      DOI: 10.1002/aic.15503
  • Spatial and Temporal Scaling of Unequal Microbubble Coalescence
    • Authors: Rou Chen; Huidan Whitney Yu, Likun Zhu, Taehun Lee, Raveena M. Patil
      Abstract: We numerically study coalescence of air microbubbles in water, with density ratio 833 and viscosity ratio 50.5, using lattice Boltzmann method. The focus is on the effects of size inequality of parent bubbles on the interfacial dynamics and coalescence time. Twelve cases, varying the size ratio of large to small parent bubble from 5.33 to 1, are systematically investigated. The “coalescence preference”, coalesced bubble closer to the larger parent bubble, is well observed and the captured power‐law relation between the preferential relative distance χ and size inequality γ, χ ∼ γ−2.079, is consistent to the recent experimental observations. Meanwhile, the coalescence time also exhibits power‐law scaling as T ∼ γ−0.7, indicating that unequal bubbles coalesce faster than equal bubbles. Such a temporal scaling of coalescence on size inequality is believed to be the first‐time observation as the fast coalescence of microbubbles is generally hard to be recorded through laboratory experimentation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-16T18:05:54.018584-05:
      DOI: 10.1002/aic.15504
  • High‐rate hydrogen separation using an MIEC oxygen permeable
           membrane reactor
    • Authors: Wenping Li; Zhongwei Cao, Xuefeng Zhu, Weishen Yang
      Abstract: In this study, we propose using mixed ionic‐electronic conducting (MIEC) oxygen permeable membrane to separate hydrogen via the water splitting reaction. To do that, steam was fed to one side of the membrane (side I) and a low‐purity hydrogen was fed to the other side (side II). Oxygen from water splitting on side I permeates through the membrane driven by an oxygen chemical potential gradient across the membrane to react with the low‐purity hydrogen on side II. After condensation and drying, high‐purity hydrogen is acquired from side I. Thus, the hydrogen separation process is realized based on the fact that the low‐purity hydrogen is consumed and high‐purity hydrogen is acquired. We achieved a high hydrogen separation rate (13.5 mL cm−2 min−1) at 950°C in a reactor equipped with a 0.5‐mm‐thick Ba0.98Ce0.05Fe0.95O3‐δ membrane. This research proofed that it is feasible to upgrade hydrogen purity using an MIEC oxygen permeable membrane. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-12T04:15:23.29002-05:0
      DOI: 10.1002/aic.15502
  • Splitting CO2 with a ceria‐based redox cycle in a solar‐driven
           thermogravimetric analyzer
    • Authors: M. Takacs; S. Ackermann, A. Bonk, M. Neises‐von Puttkamer, Ph. Haueter, J.R. Scheffe, U.F. Vogt, A. Steinfeld
      Abstract: Thermochemical splitting of CO2 via a ceria‐based redox cycle was performed in a solar‐driven thermogravimetric analyzer. Overall reaction rates, including heat and mass transport, were determined under concentrated irradiation mimicking realistic operation of solar reactors. Reticulated porous ceramic (RPC) structures and fibers made of undoped and Zr4+‐doped CeO2, were endothermally reduced under radiative fluxes of 1280 suns in the temperature range 1200‐1950 K and subsequently re‐oxidized with CO2 at 950‐1400 K. Rapid and uniform heating was observed for 8 ppi ceria RPC with mm‐sized porosity due to its low optical thickness and volumetric radiative absorption, while ceria fibers with μm‐sized porosity performed poorly due to its opacity to incident irradiation. The 10 ppi RPC exhibited higher fuel yield because of its higher sample density. Zr4+‐doped ceria showed increasing reduction extents with dopant concentration but decreasing specific CO yield due to unfavorable oxidation thermodynamics and slower kinetics. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-12T03:35:31.982987-05:
      DOI: 10.1002/aic.15501
  • Pinch‐based Shortcut Method for the Conceptual Design of Adiabatic
           Absorption Columns
    • Authors: Christian Redepenning; Wolfgang Marquardt
      Abstract: Shortcut methods are valuable tools for the fast evaluation of key performance indicators in the early phase of conceptual process design. For the design of absorption columns, operation at minimum solvent demand represents a thermodynamically sound indicator, which is, however, difficult to determine because an infinite number of separation stages need to be considered. Instead, the suggested shortcut model exploits the existence of the pinch point to identify operation at minimum solvent demand. Existing shortcut concepts, such as the well‐known equation of Kremser\,(1930), are significantly outperformed by the novel shortcut model, which can be gradually refined to any desired accuracy. Integration into a stepwise procedure results in reliable solutions. The model covers rigorous thermodynamics; no simplifications regarding phase equilibrium, heat effects, or number of components are required. The performance of the method is illustrated by several case studies with up to seven components. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-08T03:50:19.959463-05:
      DOI: 10.1002/aic.15499
  • Pinched Tube Flow Reactor: Hydrodynamics and Suitability for Exothermic
           Multiphase Reactions
    • Authors: Mrityunjay K. Sharma; Shital B. Potdar, Amol A. Kulkarni
      Abstract: A novel tubular flow reactor where a straight tube is modified by pinching it periodically at a fixed pitch and at different angles is presented. Pinched tubes (straight tube as well as helical coils) with different pitch and angles between successive pinching are studied. This work reports a detailed hydrodynamic study involving single and two phase flow. Mixing experiments showed that having an angle of 90° between successive pinchs achieves the shortest mixing length when compared to lower angles. Pressure recovery along with sequence of high and low shear zones and change of flow direction imposed better mixing. RTD studies showed that higher number of pinch sections decreases the extent of dispersion, yet it deviates from plug flow. The performance is evaluated by carrying a homogeneous and two‐phase aromatic nitration and also liquid‐liquid extraction. Pinched tube presents an economical option as a flow reactor for conducting exothermic reactions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-07T18:45:43.619172-05:
      DOI: 10.1002/aic.15498
  • Highly stable hydrophobic SiNCO nanoparticle‐modified silicon nitride
           membrane for zero‐discharge water desalination
    • Authors: Jun‐Wei Wang; Lin Li, Jian‐Qiang Gu, Ming‐Ye Yang, Xin Xu, Chu‐Sheng Chen, Huan‐Ting Wang, Simeon Agathopoulos
      Abstract: Membrane distillation water desalination can attain a significantly higher water recovery than reverse osmosis, while the lack of stable hydrophobic membranes limits its commercial applications. This paper presents the preparation of a new hydrophobic membrane by modifying a porous Si3N4 substrate with vesicular SiNCO nano‐particles. The membrane had a water contact angle of 142°, due to the presence of ‐Si‐CH3 terminal groups and the high surface roughness. The contact angle remained nearly the same after exposures of the membrane to boiling water, aqueous solutions with pH ranging from 2 to 12, and benzene. The membrane exhibited satisfactory water desalination performance on highly concentrated NaCl solutions and simulated seawater. With the highly stable membrane, it is promising to develop a zero‐discharge water desalination process for simultaneous production of fresh water for daily uses and brine for industrial uses. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-07T18:45:29.116822-05:
      DOI: 10.1002/aic.15500
  • Kinetics of Homogeneous 5‐Hydroxymethylfurfural Oxidation to
           2,5‐Furandicarboxylic Acid with Co/Mn/Br Catalyst
    • Authors: Xiaobin Zuo; Amit S. Chaudhari, Kirk Snavely, Fenghui Niu, Hongda Zhu, Kevin J. Martin, Bala Subramaniam
      Abstract: 2,5‐furandicarboxylic acid (FDCA) is a potential non‐phthalate based bio‐renewable substitute for terephthalic acid (TPA)‐based plastics. Herein, we present an investigation of the oxidation rate of 5‐hydroxymethylfurfural (HMF) to FDCA in acetic acid medium using Co/Mn/Br catalyst. Transient concentration profiles of the reactant (HMF), intermediates [2,5‐diformylfuran (DFF), 5‐formyl‐2‐furancarboxylic acid (FFCA)] and the final product (FDCA) were obtained for this relatively fast reaction in a stirred semi‐batch reactor using rapid in‐line sampling. Comparison of the effective rate constants for the series oxidation steps with predicted gas‐liquid mass transfer coefficients reveal that except for the FFCA → FDCA step, the first two oxidation steps are subject to gas‐liquid mass transfer limitations even at high stirrer speeds. Novel reactor configurations, such as a reactor in which the reaction mixture is dispersed as fine droplets into a gas phase containing oxygen are required to overcome oxygen starvation in the liquid phase and further intensify FDCA production. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-04T22:05:30.502232-05:
      DOI: 10.1002/aic.15497
  • Mixing and residence time distribution in ultrasonic microreactors
    • Authors: Zhengya Dong; Shuainan Zhao, Yuchao Zhang, Chaoqun Yao, Guangwen Chen, Quan Yuan
      Abstract: Intensification of liquid mixing was investigated in domestic fabricated ultrasonic microreactors. Under the ultrasonic field, cavitation bubbles were generated, which undergo vigorous translational motion and surface oscillation with different modes (volume, shape oscillation and transient collapse). These cavitation phenomena induce intensive convective mixing and reduce the mixing time from 24‐32 s to 0.2‐1.0 s. The mixing performance decreases with the channel size, due to the weaker cavitation activity in smaller channel. The energy efficiency is comparable to that of the conventional T‐type and higher than the Y‐type and Caterpillar microreactors. Residence time distribution (RTD) was also measured by a stimulus‐response experiment and analyzed with axial dispersion model. Axial dispersion was significantly reduced by the ultrasound‐induced radial mixing, leading to the increasing of Bo number with ultrasound power. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-02T14:05:57.153148-05:
      DOI: 10.1002/aic.15493
  • CO2 Methanation: Optimal Start‐Up Control of a Fixed‐Bed Reactor for
           Power‐To‐Gas Applications
    • Authors: Jens Bremer; Karsten H. G. Rätze, Kai Sundmacher
      Abstract: Utilizing volatile renewable energy sources (e.g., solar, wind) for chemical production systems requires a deeper understanding of their dynamic operation modes. Taking the example of a methanation reactor in the context of power‐to‐gas applications, a dynamic optimization approach is used to identify control trajectories for a time optimal reactor start‐up avoiding distinct hot spot formation. For the optimization, we develop a dynamic, two‐dimensional model of a fixed‐bed tube reactor for carbon dioxide methanation which is based on the reaction scheme of the underlying exothermic Sabatier reaction mechanism. While controlling dynamic hot spot formation inside the catalyst bed, we prove the applicability of our methodology and investigate the feasibility of dynamic carbon dioxide methanation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-02T14:00:25.30614-05:0
      DOI: 10.1002/aic.15496
  • Atomically dispersed Pd on nanostructured TiO2 for NO removal by solar
    • Authors: Kakeru Fujiwara; Sotiris E. Pratsinis
      Abstract: Reducing the particle size of noble metals on ceramic supports can maximize noble metal performance and minimize its use. Here Pd clusters onto nanostructured TiO2 particles are prepared in one step by scalable flame aerosol technology while controlling the Pd cluster size from a few nanometers to that of single atoms. Annealing such materials at appropriate temperatures leads to solar photocatalytic NOx removal in a standard ISO reactor up to10 times faster than that of commercial TiO2 (P25, Evonik). Such superior performance can be attained by only 0.1 wt% Pd loading on TiO2. Annealing these flame‐made powders in air up to 600 oC decreases the amorphous TiO2 fraction and increases its crystal and particle sizes as observed by X‐ray diffraction (XRD) and N2 adsorption. The growth of single Pd atoms to Pd clusters on TiO2 prepared at different Pd loading and annealing conditions was investigated by scanning transmission electron microscopy (STEM) and XRD.The single Pd atoms and clusters on TiO2 are stable up to, at least, 600 oC for 2 hours in air but at 800 oC they grow into PdO nanoparticles whose fraction is comparable with the nominal Pd loading. Hence, most of Pd atoms are on the TiO2 surface where at 800 oC they diffuse and coalesce. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) reveals NO adsorption on single, double, 3‐ and 4‐fold coordinated Pd atoms depending on their synthesis and annealing conditions. The peak intensity of NO adsorption sites involving multiple Pd atoms is substantially lower in TiO2 containing 0.1 wt% than 1 wt% Pd but that intensity from single Pd atoms is comparable. This indicates the dominance of isolated Pd atoms compared to clusters in Pd/TiO2 containing 0.1 wt% Pd that match or exceed the photocatalytic NOx removal of Pd/TiO2 of higher Pd contents. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-02T13:55:25.565223-05:
      DOI: 10.1002/aic.15495
  • Liquid‐Phase Axial Dispersion of Turbulent Gas‐Liquid Co‐Current
           Flow through Screen‐type Static Mixers
    • Authors: Fouad Azizi; Khaled Abou Hweij
      Abstract: This paper discusses the characteristics of turbulent gas‐liquid flow through tubular reactors/contactors equipped with screen‐type static mixers from a macromixing perspective. The effect of changing the reactor configuration, and the operating conditions, were investigated by using four different screen geometries of varying mesh numbers.Residence time distribution experiments were conducted in the turbulent regime (4,500 
      PubDate: 2016-09-02T12:45:23.463773-05:
      DOI: 10.1002/aic.15494
  • Preparation of open‐cell foams from polymer blends by supercritical CO2
           and their efficient oil‐absorbing performance
    • Authors: Yu‐Wei Fang; Jin‐Biao Bao, Hai‐Kuo Yan, Wei Sun, Ling Zhao, Guo‐Hua Hu
      Abstract: This letter reports on the hydrophobicity and oleophilicity of open‐cell foams from polymer blends prepared by supercritical CO2. A typical bulk density of the foam is measured to be 0.05 g/cm3. The contact angle of the foam with water is determined to be 139.2°. The foam can selectively absorb the diesel from water with the uptake capacity of 17.0 g/g. The foams are technologically promising for application of oil spill cleanup. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-02T12:35:22.063477-05:
      DOI: 10.1002/aic.15492
  • Novel Fe/MnK‐CNTs Nanocomposites as Catalysts for Direct Production of
           Lower Olefins from Syngas
    • Authors: Di Wang; Jian Ji, Bingxu Chen, Wenyao Chen, Gang Qian, Xuezhi Duan, Xinggui Zhou, Di Wang, Anders Holmen, De Chen, John C. Walmsley
      Abstract: Novel Fe/MnK‐CNTs nanocomposites are developed as catalysts for direct production of lower olefins from syngas, delivering a high iron time yield of 337.2 μmolCO·gFe−1·s−1 with 51.3%C selectivity toward C2‐C4 olefins under the optimal reaction conditions (270 oC, 2.0 MPa, 30000 mL·h−1·gcat−1). These catalysts are optimized by varying calcination temperature from 150 to 400 oC. Multiple techniques including TEM, Elemental mapping, XRD, XPS, H2‐TPR and Raman were employed to reveal the relationship between the catalyst nature and unique catalytic behavior. In particular, the resultant catalyst from the calcination temperature of 220 oC exhibits the highest selectivity of C2‐C4 olefins as well as good stability, which are enabled by the trade‐off among the effects of iron particle sizes, promoters, metal‐support interaction and support surface chemistry. Moreover, influences of reaction temperature, reaction pressure and space velocity are also investigated. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-31T18:50:34.976448-05:
      DOI: 10.1002/aic.15490
  • Meso‐scale statistical properties of gas‐solid flow a direct numerical
           simulation (DNS) study
    • Authors: Xiaowen Liu; Limin Wang, Wei Ge
      Abstract: Statistical properties of particles in heterogeneous gas‐solid flow were numerically investigated based on the results of a three‐dimensional large‐scale direct numerical simulation (DNS). Strong scale‐dependence and local non‐equilibrium of these properties, especially the particle fluctuating velocity (PFV) or granular temperature, were observed to be related to the effect of meso‐scale structures formed by the compromise in competition between fluid and particle dominated mechanisms. To quantify such effects, the heterogeneous structures were partitioned into a gas‐rich dilute phase and a solid‐rich dense phase according to the particle‐scale voidage defined through the Voronoi tessellation. Non‐equilibrium features, such as the deviation of PFV from Gaussian distribution and anisotropy, were found even in phase‐specific properties. A new distribution function for the PFV well characterizing these features was obtained by fitting the DNS results, which takes a typical bi‐disperse mode, with phase‐specific granular temperatures. The implications of these findings to the kinetic theory of granular flow and traditional continuum models of gas‐solid flow were also discussed. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-31T18:50:25.336157-05:
      DOI: 10.1002/aic.15489
  • Kinetics of oxidative cracking of n‐hexane to olefins over
           VOx/Ce‐Al2O3 under gas phase oxygen‐free environment
    • Authors: AbdAlwadood H. Elbadawi; Muhammad Y. Khan, Mohammad R. Quddus, Shaikh A. Razzak, Mohammad M. Hossain
      Abstract: The kinetics of oxidative cracking of n‐hexane to olefins using lattice oxygen of VOx/Ce‐Al2O3 is investigated. The TPR/TPO analysis shows a consistent reducibility (79%) of VOx/Ce‐Al2O3 in repeated redox cycles. The total acidity of the sample is found to be 0.54 mmol/g with 22% are strong acid sites that favors olefin selectivity. The oxidative cracking of n‐hexane in a fluidized CREC Riser simulator gives approximately 60% olefin selectivity at 30% n‐hexane conversion. A kinetic model is developed considering (i) cracking, (ii) ODH and (iii) catalyst deactivations. The proposed cracking mechanism considers adsorption, C‐H and C‐C bond fission and desorption as elementary steps and implemented by pseudo steady state hypothesis. A Langmuir‐Hinshelwood mechanism is found to represent the ODH reactions. The developed model fits the experimental data with favorable statistical indicators. The estimated specific reaction rate constants are also found to be consistent with the product selectivity data. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-31T18:50:22.655638-05:
      DOI: 10.1002/aic.15491
  • Ionic liquids in supercritical methanol greatly enhance
           transesterification reaction for high‐yield biodiesel production
    • Authors: V. M. Ortiz‐Martínez; M. J. Salar‐García, P. Olivares‐Carrillo, F.J. Hernández‐Fernández, A.P. de los Ríos, J. Quesada‐Medina
      Abstract: Biodiesel production is one of the most promising future alternatives to replacing fossil fuels. This work studies the use of ionic liquids (ILs) as potential catalysts in supercritical methanol for biodiesel production from non‐edible oil. The transesterification reaction of karanja oil was investigated in supercritical methanol in the presence of two respective ionic liquids, [BMIM+][HSO4‐] and [Chol+][H2PO4‐]. The reaction was performed in a one‐step batch process at several temperatures and percentages by weight of catalyst (w/woil). The results obtained show that the ionic liquid [Chol+][H2PO4‐] allows a high yield of fatty acid methyl esters (FAMEs) to be achieved in a short reaction time (above 95% in 45 min). A catalytic mechanism is also proposed for the ionic liquid that offered significant catalytic activity. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-31T18:45:21.800097-05:
      DOI: 10.1002/aic.15488
  • Immersed Boundary Method (IBM) Based Direct Numerical Simulation of
           Open‐cell Solid Foams: Hydrodynamics
    • Authors: Saurish Das; Niels G. Deen, J.A.M. Kuipers
      Abstract: A sharp interface implicit Immersed Boundary Method (IBM) is developed and used for direct numerical simulations of the flow through open‐cell solid foams with a cellular structure. The complex solid structure of the foam is resolved on a non‐boundary fitted Cartesian computational‐grid. A single representative unit cell of the foam is considered in a periodic domain, and its geometry is approximated based on the structural packing of a tetrakaidecahedron. Simulations are performed for a wide range of porosities (0.638‐0.962) and Reynolds numbers (0‐500). Flow is enforced by applying a constant body force (momentum source) for three different flow directions along the {100}, {110} and {111} lattice‐vectors. The drag force on the foam is calculated and a non‐dimensional drag/pressure drop correlation is proposed that fits the entire data set with an average deviation of $5.6\%$. Moreover, the accurate numerical simulations have helped to elucidate the detailed fluid‐solid interaction in complex porous media. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-29T04:05:23.35459-05:0
      DOI: 10.1002/aic.15487
  • Curing Kinetics of Bio‐based Epoxy Resin Based on Epoxidized Soybean Oil
           and Green Curing Agent
    • Authors: Yahua Chen; Zhenhao Xi, Ling Zhao
      Abstract: New thermosets with high bio‐based content was synthesized by curing epoxidized soybean oil (ESO) with a green curing agent maleopimaric acid (MPA) catalyzed by 2‐ethly‐4‐methylimidazole (EMI). Non‐isothermal differential scanning calorimetry (DSC) and a relatively new integral isoconversional method were used to analyze the curing kinetic behaviors and determine the activation energy (Ea). The two‐parameter Šesták–Berggren autocatalytic model was applied in the mathematical modeling to obtain the reaction orders and the pro‐exponential factor. For anhydride/epoxy group molar ratio equal to 0.7, Ea decreased from 82.70 kJ/mol to 80.17 kJ/mol when increasing the amount of catalyst from 0.5 to 1.5 phr toward ESO. The reaction orders m and n were 0.4148 and 1.109, respectively. The predicted non‐isothermal curing rates of Šesták–Berggren model matched perfectly with the experimental data. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-25T17:45:47.159219-05:
      DOI: 10.1002/aic.15486
  • On the temperature control in a micro structured packed bed reactor for
           methanation of CO/CO2 mixtures
    • Authors: Michael Belimov; David Metzger, Peter Pfeifer
      Abstract: Micro reactor technology is widely used for process intensification and is essential for fast and strongly exothermic reactions exhibiting mass and heat transfer limitations. In the scope of the MINERVE Power‐to‐Gas project, sponsored by KIC InnoEnergy from 2012‐2015, a micro packed bed reactor was developed for conversion of syngas containing CO2 into methane. This work focuses on heat removal and temperature control in a manufactured device using syngas throughputs less than 1.4 Nm3/h (10% CO, 7% CO2, H2/C=4) while examining the cooling potential of different cooling fluids e.g. air, steam and water. The benefits of the system are elucidated and compared against present technologies. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-22T08:35:27.653418-05:
      DOI: 10.1002/aic.15461
  • Influence of ionic liquid composition on the stability of PVC‐based
           ionic liquid inclusion membranes in aqueous solution
    • Authors: F. Tomás‐Alonso; M.J. Salar‐García, V.M. Ortiz‐Martínez, A. M. Rubio, A. Giménez, F.J. Hernández‐Fernández, A. P. de los Ríos
      Abstract: Membrane technology has gained significant importance with the incorporation of ionic liquids into their structure. This work shows the influence of ionic liquid composition on the stability of PVC‐based polymer ionic liquid inclusion membranes (PILIMs) in aqueous solution. Among the ILs investigated, those membranes which contain between 20 ‐ 30%w/w of the least soluble, [OMIM+][PF6‐] and [OMIM+][Ntf2‐], exhibit losses of IL lower than 10%. For both ILs, the amount immobilized was maximum for the membranes with 30%w/w of IL (0.0838 and 0.0832 g, respectively). On the contrary, the ionic liquid loss increases as its solubility in water increase, reaching 99.52% when PILIMs are prepared with 70%w/w of [OMIM+][BF4‐]. The results demonstrate that the stability of PILIMs depends on the solubility of the IL in the surrounding phase and the specific interaction between the IL and the polymeric support for PVC‐to‐IL ratios higher than 30%w/w. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-20T03:56:08.781953-05:
      DOI: 10.1002/aic.15460
  • Scaling of Continuous Twin Screw Wet Granulation
    • Authors: Juan G. Osorio; Ridade Sayin, Arjun V. Kalbag, Laura Martinez‐Marcos, Dimitrios A. Lamprou, Gavin W. Halbert, James D. Litster
      Abstract: Scaling rules were developed and tested for a continuous twin screw wet granulation process using three scales (11mm, 16mm and 24mm barrel diameter) of twin screw granulators (TSG). The distributive feed screw (DFS) configuration used produced high porosity granules (50‐60%) with broad bimodal size distributions, especially in the 16mm and 24mm TSGs. Three dimensionless numbers, Froude number (Fr), liquid‐to‐solid ratio (LSR), and powder feed number (PFN), were identified and their effect on granule size distribution, porosity and liquid distribution tested. Granule size increased with increasing LSR as expected. However, Fr and PFN had no significant effect on d10 or d50 and only a small effect on d90. In contrast, granulator scale had a strong effect on granule size distribution, with d90 increasing almost linearly with barrel diameter. This is consistent with breakage of large granules being a dominant mechanism and directly controlled by the geometry of the screw. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-19T04:05:32.353007-05:
      DOI: 10.1002/aic.15459
  • Thermo‐hydraulic analysis of refinery heat exchangers undergoing
    • Authors: E. Diaz‐Bejarano; F. Coletti, S. Macchietto
      Abstract: A complete, systematic approach is presented for the analysis and characterization of fouling and cleaning in refinery heat exchangers. Bringing together advanced thermo‐hydraulic dynamic models, some new formulations, and a method for dynamic analysis of plant data, it allows: extracting significant information from the data; evaluating the fouling state of the units based on thermal measurements and pressure drops, if available; identifying the range of deposit conductivity leading to realistic pressure drops, if pressure measurements are unavailable; estimating key fouling and ageing parameters; estimating the effectiveness of cleaning and surface conditions after a clean; and predicting thermal and hydraulic performance with good accuracy for other periods/exchangers operating in similar conditions. An industrial case study demonstrates the performance prediction in seamless simulations that include partial and total cleanings for over 1000 days operation. The risks of using thermal effects alone and the significant advantages of including pressure drop measurements are highlighted. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-17T17:50:46.204889-05:
      DOI: 10.1002/aic.15457
  • Effect of Bed Characteristics on Local Liquid Spreading in a Trickle Bed
    • Authors: Arpit Jindal; Vivek V. Buwa
      Abstract: Trickle bed reactors are important to several chemical process applications. While the available CFD models can predict overall liquid volume fraction, the prediction of spatial liquid distribution continues to be a challenging task. In the present work, Eulerian multi‐fluid simulations were performed to investigate the effects of particle size, gas and liquid flow rates and bed structure on local liquid spreading and the predictions were validated using measured liquid spreading. It was found that the capillary pressure force caused liquid to spread in the lateral direction and that the interphase interaction forces pushed it in the downward direction and the relative magnitudes of these forces governed the local liquid distribution. While the use of existing capillary pressure force model led to satisfactory prediction of the observed trends of dynamic and steady state local liquid spreading, the modified capillary pressure force led to quantitatively correct predictions of local liquid spreading. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-17T17:50:41.640295-05:
      DOI: 10.1002/aic.15455
  • Current distribution in a rectangular flow channel manufactured by
    • Authors: H.A. Figueredo; R.D. McKerracher, C. Ponce de León, F.C. Walsh
      Abstract: The characterization and improvement of the rectangular channel electrolyte flow compartment used in an iron‐air flow battery was carried out by using an arrangement of copper electrodes to measure the current density distribution employing the limiting current technique. The present work addresses the hydrodynamics and mass transport distribution in the compartment and their improvement by an improved electrolyte compartment that results in a more uniform current distribution. The current distribution was evaluated as the ratio between the local and the averaged limiting current densities during the reduction of copper ions over a range of mean linear flow velocity across the electrode surface (2‐30 cm s−1).The initial compartment, showed larger differences between the minimum and maximum currents than the electrolyte compartment that resulted as part of the design process and showed a higher pressure drop at a given mean linear flow velocity. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-17T03:30:39.51741-05:0
      DOI: 10.1002/aic.15454
  • Aerosol Analysis of Residual and Nanoparticle Fractions from Spray
           Pyrolysis of Poorly Volatile Precursors
    • Authors: Juha Harra; Sonja Kujanpää, Janne Haapanen, Paxton Juuti, Leo Hyvärinen, Mari Honkanen, Jyrki M. Mäkelä
      Abstract: The quality of aerosol‐produced nanopowders can be impaired by micron‐sized particles formed due to non‐uniform process conditions. Methods to evaluate the quality reliably and fast, preferably on‐line, are important at industrial scales. Here, aerosol analysis methods are used to determine the fractions of nanoparticles and micron‐sized residuals from poorly volatile precursors. This is accomplished by using aerosol instruments to measure the number and mass size distributions of Liquid Flame Spray‐generated alumina and silver particles produced from metal nitrates dissolved in ethanol and 2‐ethylhexanoic acid (EHA). The addition of EHA had no effect on silver, whereas, 5\% EHA concentration was enough to shift the alumina mass from the residuals to nanoparticles. The size‐resolved aerosol analysis proved to be an effective method for determining the product quality. Moreover, the used on‐line techniques alone can be used to evaluate the process output when producing nanopowders, reducing the need for tedious off‐line analyses. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-11T23:40:36.689005-05:
      DOI: 10.1002/aic.15449
  • A Positron Emission Particle Tracking investigation of the scaling law
           governing free surface flows in tumbling mills
    • Authors: I. Govender; M. C. Richter, D. N. De Klerk, A. N. Mainza
      Abstract: Positron Emission Particle Tracking (PEPT) measurements are used to track the flow of d = 5mm glass beads within a rotating drum fitted with (and without) lifter bars and operated in the cascading and cataracting Froude regimes. After converting the Lagrangian trajectories of a representative radio‐labelled glass bead (the tracer) into Eulerian fields under the ergodic assumption, the bed shape and kinematics are extracted for steady, fully developed flow conditions. Notwithstanding the azimuthal wall effects introduced by the lifter bars, we show a linear scaling 〈v〉∝h of the local flowing layer thickness h with local depth‐averaged velocity 〈 v 〉and a constant average shear 〈γ̇〉∼0.6gd for direct measurements spanning the entire flowing layer (not just the central region), and high Froude regimes (cascading and cataracting) not previously investigated by scaling analysis in the literature. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-11T23:40:34.187218-05:
      DOI: 10.1002/aic.15453
  • Thermodynamic Analysis and Optimization of RWGS Processes for Solar Syngas
           Production from CO2
    • Authors: Marcus Wenzel; Liisa Rihko‐Struckmann, Kai Sundmacher
      Abstract: Process systems were investigated for syngas production from CO2 and renewable energy (solar) by the reverse water‐gas shift (RWGS) and the reverse water‐gas shift chemical looping (RWGS‐CL) process. Thermodynamic analysis and optimization was performed to maximize the solar‐to‐syngas (StS) efficiency ηStS. Special emphasis was laid on product gas separation. For RWGS‐CL, a maximum StS efficiencies of 14.2 and 14.4% were achieved without and with heat integration, respectively. The StS efficiency is dictated by the low overall efficiency of H2 production. RWGS‐CL is most beneficial for the production of pure CO, where the StS efficiency is one percent point higher compared to that of the RWGS process with heat integration. Heat integration leads to significant reductions in external heat demand since most of the gas phase process heat can be integrated. The StS efficiencies for RWGS and RWGS‐CL achieve the same level as the reported values for solar thermochemical syngas production. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-11T03:45:57.466224-05:
      DOI: 10.1002/aic.15445
  • Identification of Cell‐Nucleation Mechanism in Foam Injection Molding
           with Gas‐counter Pressure via Mold Visualization
    • Authors: Vahid Shaayegan; Guilong Wang, Lun Howe Mark, Chul B. Park
      Abstract: The mechanisms of cell nucleation and growth are investigated in foam injection molding using gas‐counter pressure (GCP). An in‐situ mold visualization technique is employed. The application of GCP suppresses cell nucleation, and prevents the blowing agent from escaping during mold‐filling. The inherent structural heterogeneity in the regular foam injection molding can be improved because of the uniform cavity pressure when employing GCP. The cavity pressure profiles show much faster pressure‐drop rates using GCP, because the single‐phase polymer/gas mixture has a lower compressibility than the two‐phase polymer/bubble mixture. Therefore, both the cell nucleation and growth rates are significantly increased through a higher pressure‐drop rate upon the removal of the GCP. The effect of GCP magnitude on the cell morphology is explored. When the GCP is lower than the solubility pressure, bimodal foaming occurs. As the GCP increases above the solubility pressure, the cell density increases because of the higher pressure‐drop rate. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-23T02:50:38.033947-05:
      DOI: 10.1002/aic.15433
  • Visualization and simulation of the transfer process of index‐matched
           silica microparticle inks for gravure printing
    • Authors: A.M.P. Boelens; S. Lim, B.Y. Ahn, L. Francis, J.A. Lewis, J.J. de Pablo
      Abstract: A combined experimental and computational study of the transfer of transparent index‐matched silica‐particle inks between two flat plates is presented for gravure printing applications. The influence of printing speed and initial ink droplet size on the ability to accurately transfer ink during the printing process is explored systematically. Smooth interface Volume Of Fluid simulations are able to capture experimentally observed ink transfer over a wide range of printing speeds for inks having a modest to intermediate content of silica particles. However, for high‐content silica‐particle inks, transfer is structurally underpredicted. Our calculations indicate that for ink droplets with characteristic dimensions in the vicinity of 10, which are of particular interest for gravure printing applications, ink transfer improves due to the diminishing effect of gravity, and the increased importance of capillary forces at small length scales. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-27T13:25:23.67395-05:0
      DOI: 10.1002/aic.15392
  • Issue information - table of contents
    • Pages: 3825 - 3825
      PubDate: 2016-10-04T09:43:03.122717-05:
      DOI: 10.1002/aic.15000
  • High-throughput methods using composition and structure spread libraries
    • Authors: John R. Kitchin; Andrew J. Gellman
      Pages: 3826 - 3835
      PubDate: 2016-05-27T11:00:41.004187-05:
      DOI: 10.1002/aic.15294
  • Metal-organic framework membrane process for high purity CO2 production
    • Authors: Zebao Rui; Joshua B. James, Alexandra Kasik, Y. S. Lin
      Pages: 3836 - 3841
      Abstract: Gas separation by metal-organic framework (MOF) membranes is an emerging research field. Their commercial application potential is, however, still rarely explored due in part to unsatisfied separation characteristics and difficulty in finding suitable applications. Herein, we report “sharp molecular sieving” properties of high quality isoreticular MOF-1 (IRMOF-1) membrane for CO2 separation from dry, CO2 enriched CO2/CH4, and CO2/N2 mixtures. The IRMOF-1 membranes exhibit CO2/CH4 and CO2/N2 separation factors of 328 and 410 with CO2 permeance of 2.55 × 10−7 and 2.06 × 10−7 mol m−2 s−1 Pa−1 at feed pressure of 505 kPa and 298 K, respectively. High grade CO2 is efficiently produced from the industrial or lower grade CO2 feed gas by this MOF membrane separation process. The demonstrated “sharp molecular sieving” properties of the MOF membranes and their potential application in production of value-added high purity CO2 should bring new research and development interest in this field. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3836–3841, 2016
      PubDate: 2016-06-20T09:37:11.474739-05:
      DOI: 10.1002/aic.15367
  • Modeling bread baking with focus on overall deformation and local porosity
    • Authors: Vincent Nicolas; Fernanda Vanin, David Grenier, Tiphaine Lucas, Christophe Doursat, Denis Flick
      Pages: 3847 - 3863
      Abstract: A two dimensional model of bread baking was developed including, for the first time, the dependence of dough viscosity on both temperature and moisture content, the carbon dioxide dissolved from liquid water together with gas generation from yeast at the beginning of baking and the shrinkage due to dough drying. Particular attention was paid to experimental validation of both overall and local variables such as local temperature, overall mass loss, and local moisture content, overall CO2 released into the oven, and overall deformation and local expansion or shrinkage. Sensitivity studies on generation of carbon dioxide, gravity, and shrinkage are presented to discuss their influences on bread geometry, porosity (reflecting the alveolar structure) and gas pressure. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3847–3863, 2016
      PubDate: 2016-07-15T09:55:28.465762-05:
      DOI: 10.1002/aic.15301
  • Tailored synthesis of macroporous Pt/WO3 photocatalyst with nanoaggregates
           via flame assisted spray pyrolysis
    • Authors: Osi Arutanti; Aditya Farhan Arif, Ratna Balgis, Takashi Ogi, Kikuo Okuyama, Ferry Iskandar
      Pages: 3864 - 3873
      Abstract: High-surface-area macroporous WO3 particles with deposited Pt (Pt/WO3) were successfully synthesized for the first time, using flame-assisted spray pyrolysis. Nanoparticle aggregates-like structures (nanoaggregates) were formed, although a salt precursor was used for the synthesis. The macroporous structure was tailored by changing the mass ratio of the polystyrene template to ammonium tungstate pentahydrate. The cavities between the nanoaggregates formed mesopores, which increased the surface area. The presence of meso- and macro-pores in the synthesized Pt/WO3 particles improved their photocatalytic activities in visible-light-induced photodegradation of rhodamine B. The combination of a high surface area and the presence of an in situ-deposited Pt cocatalyst gave a high photodecomposition rate, approximately 9.6 times higher than that achieved with dense WO3 particles. This research provides a promising strategy for synthesizing submicron particles with high surface areas at a high production rate, and is suitable for industrial applications. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3864–3873, 2016
      PubDate: 2016-06-22T08:20:36.034322-05:
      DOI: 10.1002/aic.15349
  • DEM study of granular flow characteristics in the active and passive
           regions of a three-dimensional rotating drum
    • Authors: Shiliang Yang; Andy Cahyadi, Jingwei Wang, Jia Wei Chew
      Pages: 3874 - 3888
      Abstract: Three-dimensional modeling of the solid motion in a lab-scale rotating drum has been conducted via the discrete element method. After validating the simulated results with available experimental data, the active-passive interface was identified, following which particle-scale information in these two regions, in particular the influences of fill level and rotating velocity, were obtained. The results demonstrate that: (1) the total number of particles in the passive region is three times that in the active, (2) the transverse and axial velocities span a wider range in the active region, with the transverse values being greater, (3) the collision force is much higher in the active region, with the greatest magnitudes in the y direction relative to that in the x and z directions, (4) particle displacements are generally lower and have a narrower distribution in the active region, (5) the local solid residence time (SRT) distribution profiles are similar axially in that the highest SRT magnitudes are at the center region of the bed, while the other parts of the bed have uniform SRT magnitudes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3874–3888, 2016
      PubDate: 2016-05-24T10:05:33.475285-05:
      DOI: 10.1002/aic.15315
  • Dynamic population balance and flow models for granular solids in a linear
           vibrating screen
    • Authors: Nicolus Rotich; Ritva Tuunila, Ali Elkamel, Marjatta Louhi-Kultanen
      Pages: 3889 - 3898
      Abstract: Vibrating screens are a widely applied form of particle separations. In spite of this significance, their understanding is still an obstacle. Three approaches were used to characterize the flow of granular material in a linear vibrating screen. The statistical model, mass action, and kinetic model based on conservation of momentum were derived. Experiments were then conducted on a multi-sized prototype screen and glass beads of sizes 0.75, 1, 2, 3 mm. Deck inclinations were varied over 7.5,12.5, and 17.5°, and frequencies over 7, 15, and 20 Hz. A total of 72 feed batches and a constant power of 50 W was used. The experimental data was then used to validate the models. The three models provided accurate flow prediction over the screens. Additionally, the kinetic model also provided a basis for optimal design of the screening unit operation, by allowing manipulation of seven design variables to obtain a 95–100% efficient vibrating screen. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3889–3898, 2016
      PubDate: 2016-05-27T11:10:49.922276-05:
      DOI: 10.1002/aic.15318
  • Mathematical modeling of a moving bed reactor for post-combustion CO2
    • Authors: Hosoo Kim; David C. Miller, Srinivasarao Modekurti, Benjamin Omell, Debangsu Bhattacharyya, Stephen E. Zitney
      Pages: 3899 - 3914
      Abstract: A mathematical model for a moving bed reactor with embedded heat exchanger has been developed for application to solid sorbent-based capture of carbon dioxide from flue gas emitted by coal-fired power plants. The reactor model is one-dimensional, non-isothermal, and pressure-driven. The two-phase (gas and solids) model includes rigorous kinetics and heat and mass transfer between the two phases. Flow characteristics of the gas and solids in the moving bed are obtained by analogy with correlations for fixed and fluidized bed systems. From the steady-state perspective, this work presents the impact of key design variables that can be used for optimization. From the dynamic perspective, the article shows transient profiles of key outputs that should be taken into account while designing an effective control system. In addition, the article also presents performance of a model predictive controller for the moving bed regenerator under process constraints. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3899–3914, 2016
      PubDate: 2016-05-13T09:30:36.79668-05:0
      DOI: 10.1002/aic.15289
  • Carleman approximation based quasi-analytic model predictive control for
           nonlinear systems
    • Authors: Yizhou Fang; Antonios Armaou
      Pages: 3915 - 3929
      Abstract: This manuscript aims at developing a nonlinear model predictive controller formulation based on Carleman approximation. It approximates the nonlinear dynamic constraints with polynomial ones through Taylor expansion. Then, it extends the state variables to higher orders following the Kronecker product rule and expresses the nonlinear dynamic constraints with an extended bilinear representation. With little loss of nonlinear information, the formulation enables analytical prediction of future states. It also analytically calculates the sensitivity of the cost function to the manipulated inputs to facilitate the search algorithm by serving as the gradient. We present a brief analysis of error accumulation caused by Carleman approximation and then improve the accuracy of the approach by resetting extended states periodically. The idea of efficient temporal discretization is embedded in control vector parameterization to improve the controller performance. The advantages are illustrated in two applications where we solve a tracking problem and a regulation problem. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3915–3929, 2016
      PubDate: 2016-05-27T10:55:42.920318-05:
      DOI: 10.1002/aic.15298
  • Tactical capacity planning for semiconductor manufacturing: MILP models
           and scalable distributed parallel algorithms
    • Authors: Rui-Jie Zhou; Li-Juan Li
      Pages: 3930 - 3946
      Abstract: A multiperiod stochastic mixed-integer linear programming model is developed to address the tactical capacity planning of semiconductor manufacturing with considerations of complex routing of material flows, in-process inventory, demand and capacity variability, multisite production, capacity utilization rate, and downside risk management. Both planning level decisions (i.e., capacity allocation and customer service level decisions) as well as operational level decisions (i.e., production, inventory, and shipment decisions) can be simultaneously determined based on the two proposed multiobjective optimization models. To address the huge number of scenarios needed to characterize the uncertainty and the large number of first-stage integer variables in industrial scale applications, two novel scalable distributed parallel optimization algorithms are developed to mitigate the computational burden. The proposed mathematical models and algorithms are illustrated through two case studies from a major US semiconductor manufacturer. Results from these case studies provide key decision support for capacity expansion in semiconductor industry. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3930–3946, 2016
      PubDate: 2016-05-31T12:30:37.480157-05:
      DOI: 10.1002/aic.15309
  • Engineering model for intumescent coating behavior in a pilot-scale
           gas-fired furnace
    • Authors: Kristian Petersen Nørgaard; Kim Dam-Johansen, Søren Kiil, Pere Català
      Pages: 3947 - 3962
      Abstract: In the event of a fire, intumescent fire protective coatings expand and form a thermally insulating char that protects the underlying substrate from heat and subsequent structural failure. The intumescence includes several rate phenomena, which have been investigated and quantified in the literature for several decades. However, various challenges still exist. The most important one concerns mathematical model validation under realistic exposure conditions and/or time scales. Another is the simplification of advanced models to overcome the often-seen lack of a complete set of input and adjustable model parameters for a given coating, thereby providing models for industrial applications. In this work, these two challenges are addressed. Three experimental series, with an intumescent coating inside a 0.65 m3 gas-fired furnace, heating up according to so-called cellulosic fire conditions, were conducted and a very good repeatability was evident. The experiments were run for almost 3 h, reaching a final gas temperature of about 1100°C. Measurements include transient temperature developments inside the expanding char, at the steel substrate, and in the mineral wool insulation placed behind the substrate. A mathematical model, describing the intumescent coating behavior and temperatures in the furnace using a single overall reaction was developed and validated against experimental data. By including a decomposition front movement through the char, a good qualitative agreement was obtained. After further validation against experiments with other coating formulations, it has potential to become a practical engineering tool. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3947–3962, 2016
      PubDate: 2016-05-17T09:40:31.518941-05:
      DOI: 10.1002/aic.15291
  • Au/TS-1 catalyst for propene epoxidation with H2/O2: A novel strategy to
           enhance stability by tuning charging sequence
    • Authors: Xiang Feng; Yibin Liu, Yichuan Li, Chaohe Yang, Zhihua Zhang, Xuezhi Duan, Xinggui Zhou, De Chen
      Pages: 3963 - 3972
      Abstract: For propene epoxidation with H2 and O2, the catalytic performance of Au/TS-1 catalyst is extremely sensitive to preparation parameters of deposition-precipitation (DP) method. In this work, effect of charging sequence in DP process on catalyst structure and catalytic performance of Au/TS-1 catalyst is first investigated. For different charging sequences, the compositions of Au complexes (e.g., [AuCl(OH)3]−) and pore property of TS-1 (i.e., with or without H2O prefilling micropores) could affect the transfer of Au complexes into the micropores, resulting in different Au locations and thus significantly different catalytic performance. Notably, when TS-1 is first filled with H2O and then mixed with Au complexes, the reduced Au/TS-1 catalyst could expose Au nanoparticles on the external surface of TS-1 and show high stability. The results provide direct evidence showing that micropore blocking is the deactivation mechanism. Based on the results, a simple strategy to design highly stable Au/Ti-based catalysts is developed. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3963–3972, 2016
      PubDate: 2016-05-29T17:45:33.856856-05:
      DOI: 10.1002/aic.15313
  • Catalytic decomposition of propellant N2O Over Ir/Al2O3 catalyst
    • Authors: Jian Lin; Lin Li, Xiaoli Pan, Xiaodong Wang, Yu Cong, Tao Zhang, Shaomin Zhu
      Pages: 3973 - 3981
      Abstract: N2O, as a green propellant alternative to N2H4, shows potential application in satellite propulsion system. The state of Ir species and the reaction behaviors on Ir/Al2O3 in the oxidative environment during N2O decomposition were identified here. Two types of Ir sites existed in this catalyst and affected the process of N2O decomposition. The strong Ir sites facilitated the dissociative adsorption of N2O to form N2 and adsorbed O atoms with adsorption heat of as high as 281 kJ/mol, which promoted the desorption of adsorbed O atoms and favored the self-sustaining decomposition of N2O by raising the catalyst bed temperature. The other Ir sites interacted weakly with O atoms but facilitated their combination to form O2. The Ir/Al2O3 catalyst then exhibited an excellent performance in initiating the decomposition of N2O at low temperature of 200°C and good stability in 0.1 N microthruster for orbit adjustment and attitude control of satellite. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3973–3981, 2016
      PubDate: 2016-06-03T09:15:56.804678-05:
      DOI: 10.1002/aic.15324
  • Dye adsorption on zinc oxide nanoparticulates atomic-layer-deposited on
           polytetrafluoroethylene membranes
    • Authors: Sen Xiong; Liang Kong, Zhaoxiang Zhong, Yong Wang
      Pages: 3982 - 3991
      Abstract: In this work, zinc oxide (ZnO) is deposited onto porous polytetrafluoroethylene (PTFE) membranes via atomic layer deposition (ALD) and thus produced ZnO-deposited PTFE membranes are used as adsorbents for the removal of dyes from aqueous solutions. We first examine the evolution of morphology, wettability, and crystallization of PTFE membranes with ZnO ALD. The presence of ZnO nanoparticulates significantly promotes the diffusion and contact of the aqueous solutions within the membrane on one hand, and endows the membrane a strong capability to adsorb dyes from the solutions on the other. Kinetic studies reveal that the adsorption of rhodamine B and acid orange 7 by the ZnO-deposited PTFE membranes can be described by the pseudo-second-order and pseudo-first-order model, respectively, and the adsorption of both dyes follows the Langmuir isotherm. The used membranes can be easily regenerated by rinsing with ethanol and reused for multiple times without loss of removal efficiency. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3982–3991, 2016
      PubDate: 2016-05-12T10:30:27.822522-05:
      DOI: 10.1002/aic.15293
  • Determination of kinetics in batch cooling crystallization processes—A
           sequential parameter estimation approach
    • Authors: José-Francisco Pérez-Calvo; Somnath S. Kadam, Herman J. M. Kramer
      Pages: 3992 - 4012
      Abstract: A comprehensive methodology to carry out a sequential parameter estimation approach has been developed and validated for the determination of the kinetic parameters of the crystallization of a generic organic compound. The strength of the approach lies in the thorough design of isothermal experiments which facilitate the isolation and/or decoupling of the different crystallization phenomena. This methodology has been applied for the parameter estimation of primary and secondary nucleation, growth and agglomeration kinetics. The resulting crystallization model has been able to reproduce the quantiles d10, d50, and d90 of the volume-based particle size distribution of an independent seeded validation experiment with an error below 10 μm. The deviation in the prediction has been increased in the case of an independent unseeded experiment, although errors below the uncertainty of the measurement have been always obtained. The methodology here proposed is intended to be an efficient strategy for rapid modeling of batch crystallization processes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3992–4012, 2016
      PubDate: 2016-05-19T10:32:10.779201-05:
      DOI: 10.1002/aic.15295
  • In-situ cross-linked PVDF membranes with enhanced mechanical durability
           for vacuum membrane distillation
    • Authors: Jian Zuo; Tai-Shung Chung
      Pages: 4013 - 4022
      Abstract: A novel and effective one-step method has been demonstrated to fabricate cross-linked polyvinylidene fluoride (PVDF) membranes with better mechanical properties and flux for seawater desalination via vacuum membrane distillation (VMD). This method involves the addition of two functional nonsolvent additives; namely, water and ethylenediamine (EDA), into the polymer casting solution. The former acts as a pore forming agent, while the latter performs as a cross-linking inducer. The incorporation of water tends to increase membrane flux via increasing porosity and pore size but sacrifices membrane mechanical properties. Conversely, the presence of EDA enhances membrane mechanical properties through in-situ cross-linking reaction. Therefore, by synergistically combining the effects of both functional additives, the resultant PVDF membranes have shown good MD performance and mechanical properties simultaneously. The parameters that affect the cross-link reaction and membrane mechanical properties such as reaction duration and EDA concentration have been systematically studied. The membranes cast from an optimal reaction condition comprising 0.8 wt % EDA and 3-hour reaction not only shows a 40% enhancement in membrane Young's Modulus compared to the one without EDA but also achieves a good VMD flux of 43.6 L/m2-h at 60°C. This study may open up a totally new approach to design next-generation high performance MD membranes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4013–4022, 2016
      PubDate: 2016-05-27T10:35:31.251244-05:
      DOI: 10.1002/aic.15316
  • Deep oxidative–extractive desulfurization of fuels using
           benzyl-based ionic liquid
    • Authors: Mingxia Li; Zhiyong Zhou, Fan Zhang, Wenshuai Chai, Lele Zhang, Zhongqi Ren
      Pages: 4023 - 4034
      Abstract: Four benzyl-based ionic liquids (ILs) were synthetized and used for deep desulfurization of model oil and real diesel fuel. The removal efficiencies of benzothiophene (BT) and dibenzothiophene (DBT) with [Bzmim][NTf2] and [Bzmim][SCN] as extractants are higher than that with [Bzmp][NTf2] and [Bzmp][SCN] as extractants. The desulfurization capability follows the Nernst's Law. A reactive extraction mathematical model for desulfurization was established. An oxidative-extractive two-step deep desulfurization method was developed. DBT was first oxidized by H2O2 with CH3COOH as catalyst and then the unoxidized DBT and uncrystallized dibenzothiophene sulfoxide (DBTO2) in model oil were extracted by [Bzmim][NTf2], and finally the removal efficiency was 98.4% after one-stage extraction. Besides, the removal efficiency of 4,6-DMDBT was 96.4% after oxidation and one-stage extraction processes. Moreover, the oxidative-extractive two-step deep desulfurization method was also effective for desulfurization of diesel fuel. The removal efficiency of sulfur reached up to 96% after oxidation and three-stage cross-current extraction processes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4023–4034, 2016
      PubDate: 2016-06-03T09:26:52.683326-05:
      DOI: 10.1002/aic.15326
  • A novel multiscale approach for rapid prediction of phase behaviors with
           consideration of molecular conformations
    • Authors: Li Yang; Chih-Wei Chang, Shiang-Tai Lin
      Pages: 4047 - 4054
      Abstract: The conformational distribution of flexible molecules may have a significant influence on its physical properties and phase behaviors. While atomistic molecular simulations naturally include conformational changes, they are often computationally expensive and require separate simulations for each state condition. Conversely, an equation of state (EOS) provides a rapid description for a variety of fluid properties over the whole phase space; however, because of the ignorance of molecular structure, it is difficult to obtain the interaction parameters from first-principles. Here we propose a multiscale approach for simultaneous predictions of fluid properties and molecular conformational distribution. The PR+COSMOSAC EOS is used to provide the fugacity of chemical species in a mixture. The electrostatic and dispersion interactions in the EOS are determined from quantum-mechanical solvation calculations and molecular dynamics simulations at a few state points. The conformational transitions are considered as chemical reactions with the equilibrium constant determined from ab initio G4 calculations. With all the EOS parameters obtained from molecular simulations at different scales, subsequent phase equilibrium predictions can be achieved within milliseconds. We validated this approach using 1,2-dichloroethane (DCE), whose dipole moment varies from 6.34 × 10−30 C·m in the gauche-form to 0 in the trans-form. Our results show that this approach provides not only accurate predictions for the vapor–liquid and liquid–liquid equilibrium of DCE-containing fluids but also quantitative descriptions of conformational distribution of DCE in these systems. This novel method can be very useful for the prediction of thermodynamic properties of fluids with explicit inclusion of molecular conformations. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4047–4054, 2016
      PubDate: 2016-05-13T09:25:25.367932-05:
      DOI: 10.1002/aic.15290
  • Drug Release Kinetics and Mechanism from PLGA Formulations
    • Authors: Yuanhui Ji; Anna Katharina Lesniak, Anke Prudic, Raphael Paus, Gabriele Sadowski
      Pages: 4055 - 4065
      Abstract: The release kinetics of indomethacin (IND) and hydrochlorothiazide (HCT) from drug/PLGA formulations with different copolymer composition and molecular weight of PLGA were measured in vitro by using a rotating disk system (USP II). The release mechanism of IND and HCT from their PLGA formulations was analyzed using a chemical-potential-gradient model combined with the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT). Furthermore, the release kinetics of IND and HCT from the PLGA formulations with different copolymer composition and molecular weight of PLGA were correlated and predicted in good accordance with the experimental data. It was found that the chemical-potential-gradient model combined with the PC-SAFT helped to understand the drug release mechanism from the drug/PLGA formulations. It also well correlated and predicted the drug release kinetics as function of copolymer composition and molecular weight of PLGA as well as of drug type. It helps to save time and costs for determination of the long-term drug release kinetics, especially for sustained drug release as obtained from the drug/PLGA formulations in this work. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4055–4065, 2016
      PubDate: 2016-05-19T09:50:49.615879-05:
      DOI: 10.1002/aic.15282
  • A modified thermodynamic insight to deliquescence of a void-containing
           nanocrystal confirmed by MD simulation
    • Authors: Hamed Akbarzadeh; Mohsen Abbaspour, Sirous Salemi, Azizeh Masoumi, Amir Nasser Shamkhali
      Pages: 4066 - 4077
      Abstract: Existence of voids in crystalline structures can affect their physical and chemical properties considerably. When the size of the crystal reaches to nanoscale, experimental determination of its void fraction is difficult. In this work, a molecular dynamics approach is introduced to find equilibrium void fractions of a simple cubic (CsCl) and fcc (KCl) nanocrystals by determination of their deliquescence relative humidity (DRH) for different sizes and void fractions and extrapolation of the results to the bulk limit. To confirm the simulation results, the size dependency of DRH to the nanoparticle size was studied thermodynamically by inclusion of size-dependent density of water nanodroplet which leads to a simple homographic equation. This method proposes the equilibrium void percents of CsCl and KCl nanoparticles to be 10 and 15%, respectively, which are obtained by extrapolation of the results to the bulk limit. The success of obtained Möbius function was also confirmed by fitting it to experimental data for deliquescence of NaCl nanoparticles which implies the importance of considering density of water nanodroplet as a size dependent quantity. Also, using the mentioned thermodynamic approach, void dependency of deliquescence for the nanoparticles was found to be as a quasi-linear trend which is compatible with the simulation results. It is noticeable that the approach used this work for determination of equilibrium void fraction is only valid if the utilized force fields are accurate. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4066–4077, 2016
      PubDate: 2016-05-24T10:00:36.393826-05:
      DOI: 10.1002/aic.15306
  • Development of formation and growth models of CO2 hydrate film
    • Authors: Yutaka Abe; Xiao Ma, Takehiko Yanai, Kenji Yamane
      Pages: 4078 - 4089
      Abstract: This study aims to develop models to estimate the CO2 hydrate film formation and growth for different temperature and flow velocity conditions. First, the CO2 hydrate film thickness at the initial stage of its formation is experimentally measured under different temperature and flow velocity conditions using laser interferometry. Based on the results, the CO2 hydrate film thickness was found to decrease with increasing temperature and flow velocity. Next, the CO2 hydrate film formation model and growth model are developed, and the models are verified using the present experimental data. Finally, the long term growth of CO2 hydrate film thickness is estimated by the proposed growth model of CO2 hydrate film thickness. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4078–4089, 2016
      PubDate: 2016-05-26T12:40:37.175466-05:
      DOI: 10.1002/aic.15304
  • Phase behavior of system methane + hydrogen sulfide
    • Authors: Stefano Langè; Marco Campestrini, Paolo Stringari
      Pages: 4090 - 4108
      Abstract: An accurate description of the phase behavior of the CH4 + H2S system is given for temperatures from 70 K to the critical temperature of H2S and pressures up to 250 MPa. The study includes the solid phases of CH4 and H2S. A global pressure-temperature diagram is presented. The types of temperature-composition and pressure-composition phase diagrams that can be encountered in the studied temperature and pressure ranges have been described. The temperature and pressure ranges where the phase behavior of the system changes have been identified and a representative phase diagram is presented for each range. Phase diagrams have been obtained through the solid–liquid–vapor equation of state proposed by Yokozeki. The parameters of the equation of state have been regressed on all the available phase equilibrium data for the considered system. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4090–4108, 2016
      PubDate: 2016-05-29T17:35:37.426349-05:
      DOI: 10.1002/aic.15311
  • Effect of wetting difference across junction on dynamics of drops
           impacting on the junction of dual-textured surfaces
    • Authors: Visakh Vaikuntanathan; D. Sivakumar
      Pages: 4109 - 4118
      Abstract: The effect of wetting difference across the junction of smooth and groove-textured portions of a dual-textured surface on the various stages in the dynamics of liquid drops impacting on the junction is reported. Two dual-textured surfaces with substantially different wetting difference across their junction, Δθe = 65° and 25°, made of intrinsically hydrophilic stainless steel and intrinsically hydrophobic poly-di-methyl-siloxane (PDMS) are considered. The effect of wetting difference across the junction is dominantly seen on the net drop drift velocity and subsequent bulk drop movement, ξ. ξ on the PDMS dual-textured surface is less than that on the stainless dual-textured surface due to the lower wetting difference across the junction of the former. The variation of ξ with impact velocity shows a contrasting trend between the stainless steel and PDMS dual-textured surfaces due to the difference in critical impact velocity corresponding to drop impregnation on their groove-textured portions. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4109–4118, 2016
      PubDate: 2016-05-24T09:30:48.83595-05:0
      DOI: 10.1002/aic.15297
  • Analytical solutions for species transport in a T-sensor at low peclet
    • Authors: Arman Sadeghi
      Pages: 4119 - 4130
      Abstract: A 3D analytical solution is presented for the problem of mass transport in a T-sensor by taking the axial diffusion effects into account. The solution methodology is based on an eigenfunction expansion of the solute concentration and enjoys the variational calculus for the solution of the associated eigenvalue problem. The method is capable of handling a mixed electroosmotic and pressure-driven velocity profile and is executed assuming a rectangular channel cross-section although it can be easily extended to more complex geometries. Two simplified models, one based on a uniform velocity profile, valid for the channel half height to Debye length ratios of above 100, and the other based on a depthwise averaging of the species concentration to be used for cases in which the channel width to height ratio is above 5 are also presented. As a part of the latter, expressions are derived for the Taylor dispersion coefficient of the mixed flow in a slit microconduit. The most interesting finding of this study is that, when the diffusion mechanism significantly contributes to the axial movement of the species, the well-known heterogeneous mass transport evolves into a nearly uniform pattern in the depthwise direction and the mixing length noticeably increases. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4119–4130, 2016
      PubDate: 2016-05-27T11:05:57.069572-05:
      DOI: 10.1002/aic.15299
  • Investigation of inhibitors efficacy in wax deposition mitigation using a
           laboratory scale flow loop
    • Authors: Yuandao Chi; Nagu Daraboina, Cem Sarica
      Pages: 4131 - 4139
      Abstract: Statistically reliable wax inhibition experimental data was obtained by utilizing the newly built laboratory scale flow loop. The comb-shaped inhibitors are found more effective in decreasing the thickness compared to the linear inhibitor under the same conditions. Moreover, this becomes more predominant as the chain length of inhibitors increases. Interestingly, even though all the inhibitors decreased the deposit thickness, the wax content increased significantly. Besides, the longer chain length (PI-B) of the inhibitor results in a higher wax content. Since the combination of growth and aging influenced by the presence of inhibitor significantly, paraffin inhibition efficiency (PIE) based on the wax mass was proposed to quantitatively assess the inhibitors. Based on the PIE, PI-B, and PI-C have more inhibition efficiency than PI-A. Therefore, when selecting wax inhibitor, one should be aware about the strength of the deposit gel in addition to the reduction of the deposit mass. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4131–4139, 2016
      PubDate: 2016-05-27T11:10:52.977067-05:
      DOI: 10.1002/aic.15307
  • A framework for interpreting the coarsening and structural evolution of
           two co-continuous immiscible viscous fluids
    • Authors: Lee P. McMaster
      Pages: 4140 - 4156
      Abstract: Experimental data from multiple studies show the coarsening of co-continuous, high interfacial tension fluid systems is driven by capillary instabilities. Coarsening of low interfacial tension systems follows viscosity ratio dependence consistent with the pinch-off of suspended short filaments although there is uncertainty of this interpretation. The attenuation of coarsening rates for both types follows a common dependence on phase volume fraction and viscosity ratio. Dimensional analysis provides an interpretation of the transition from linear coarsening to slower nonlinear coarsening as a balance of interfacial tension driven flow and a critical level of interconnectivity. The slowdown of coarsening is consistent with the formation of discrete domains which subsequently coexist with the remaining co-continuous structure. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4140–4156, 2016
      PubDate: 2016-05-29T18:00:56.761433-05:
      DOI: 10.1002/aic.15310
  • Cyclic operation strategies in inclined and moving packed beds—Potential
           marine applications for floating systems
    • Authors: Amir Motamed Dashliborun; Faïçal Larachi, Mohsen Hamidipour
      Pages: 4157 - 4172
      Abstract: The hydrodynamics of a periodically operated packed bed subjected to column oscillations and obliquity was studied. Electrical capacitance tomography (ECT) and capacitance wire mesh sensors were employed to measure the local instantaneous liquid saturation in stationary slanted and moving packed beds, respectively. A swell simulator with six-degree-of-freedom motions was applied to emulate the behavior of floating packed beds. The results revealed that column inclination from the vertical position considerably decayed liquid waves excited by different cyclic operation strategies. However, ON–OFF liquid and gas/liquid alternating cyclic operations showed an attempt to conserve wave identity in the slanted bed and to decrease phase maldistribution resulting from bed inclination. It was also found that symmetric and non-symmetric split ratios of ON–OFF liquid cyclic mode were able to noticeably decrease fluid maldistribution in the oscillating packed bed. This study opens up possible prospects for process intensification of floating packed bed reactors and contactors. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4157–4172, 2016
      PubDate: 2016-06-02T09:18:32.600286-05:
      DOI: 10.1002/aic.15327
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