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  Subjects -> ENGINEERING (Total: 2255 journals)
    - CHEMICAL ENGINEERING (189 journals)
    - CIVIL ENGINEERING (180 journals)
    - ELECTRICAL ENGINEERING (99 journals)
    - ENGINEERING (1196 journals)
    - ENGINEERING MECHANICS AND MATERIALS (386 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (61 journals)
    - MECHANICAL ENGINEERING (89 journals)

ENGINEERING (1196 journals)            First | 1 2 3 4 5 6 | Last

Showing 201 - 400 of 1205 Journals sorted alphabetically
Current Science     Open Access   (Followers: 44)
Dams and Reservoirs     Hybrid Journal   (Followers: 3)
Data Handling in Science and Technology     Full-text available via subscription   (Followers: 5)
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 28)
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: 13)
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   (Followers: 1)
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: 17)
Energy Conversion and Management     Hybrid Journal   (Followers: 9)
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: 3)
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: 4)
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: 2)
European Physical Journal - Applied Physics     Full-text available via subscription   (Followers: 16)
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: 5)
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: 5)
Focus on Surfactants     Full-text available via subscription   (Followers: 3)
Food Engineering Reviews     Hybrid Journal   (Followers: 3)
Food Science and Technology     Open Access   (Followers: 4)
Formación Universitaria     Open Access   (Followers: 4)
FORMakademisk     Open Access  
Formal Methods in System Design     Hybrid Journal   (Followers: 6)
Forschung     Hybrid Journal   (Followers: 1)
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: 4)
Fuel Cells Bulletin     Full-text available via subscription   (Followers: 4)
Fusion Engineering and Design     Hybrid Journal   (Followers: 10)
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: 118)
Geotechnical Testing Journal     Full-text available via subscription   (Followers: 9)
Géotechnique     Hybrid Journal   (Followers: 13)
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: 3)
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: 2)
Heat Transfer - Asian Research     Hybrid Journal   (Followers: 9)
Heat Transfer Engineering     Hybrid Journal   (Followers: 25)
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: 48)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 38)
IEEE Communications Magazine     Full-text available via subscription   (Followers: 65)
IEEE Control Systems Magazine     Full-text available via subscription   (Followers: 67)
IEEE Engineering Management Review     Full-text available via subscription   (Followers: 35)
IEEE Geoscience and Remote Sensing Letters     Hybrid Journal   (Followers: 115)
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: 15)
IEEE Journal of Oceanic Engineering     Hybrid Journal   (Followers: 11)
IEEE Journal of Selected Topics in Quantum Electronics     Hybrid Journal   (Followers: 8)
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: 3)
IEEE Microwave and Wireless Components Letters     Hybrid Journal   (Followers: 17)
IEEE Microwave Magazine     Full-text available via subscription   (Followers: 31)
IEEE Potentials     Full-text available via subscription   (Followers: 19)
IEEE Signal Processing Letters     Hybrid Journal   (Followers: 36)
IEEE Spectrum     Full-text available via subscription   (Followers: 142)
IEEE Technology and Society Magazine     Full-text available via subscription   (Followers: 6)
IEEE Transactions on Advanced Packaging     Full-text available via subscription   (Followers: 7)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 37)
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: 19)
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: 31)
IEEE Transactions on Magnetics     Hybrid Journal   (Followers: 12)
IEEE Transactions on Microwave Theory and Techniques     Hybrid Journal   (Followers: 25)
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: 18)
IEEE Transactions on Professional Communication     Hybrid Journal   (Followers: 7)
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: 62)
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: 14)
IET Micro and Nano Letters     Hybrid Journal   (Followers: 6)
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 13)

  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  [1612 journals]
  • Effect of Small Amount of Water on the Dynamics Properties and
           Micro-structures of Ionic Liquids
    • Authors: Jing Zhou; Xiaomin Liu, Suojiang Zhang, Xiangping Zhang, Guangren Yu
      Abstract: In this work, a series of systems of 1-Butyl-3-methylimidazolium acetate ([Bmim][Ac]), 1-Butyl-3-methylimidazolium Tetrafluoroborate ([Bmim][BF4]), and 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmim][Tf2N]) with a small amount of water were simulated. Viscosities of systems were obtained by non-equilibrium molecule dynamics (NEMD) simulation and the results show that the viscosities change in different ways: for [Bmim][BF4] and [Bmim][Tf2N], viscosities decrease rapidly in the first stage, and then decrease slowly with the increase of water content. But for [Bmim][Ac], the viscosities increase firstly and then decrease. The unique phenomenon of [Bmim][Ac] can be attributed to the formation of chainlike structure of anion•••water•••anion•••. Hydrogen-bond (HB) interaction between ion pairs is weakened, but the number of HB between water and anions increases with increase of water content. Besides, the micro-structures of water in ILs-water systems were compared and found that the distribution of water is more concentrated in [Bmim][Tf2N]-H2O system, while it is isotropy in [Bmim][Ac]-H2O system. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-25T17:20:22.815144-05:
      DOI: 10.1002/aic.15594
       
  • Pore-Network Modeling of Particle Retention in Porous Media
    • Authors: Hongtao Yang; Matthew T. Balhoff
      Abstract: Transport and filtration of micron and submicron particles in porous media is important in applications such as water purification, contaminants dispersion, and drilling mud invasion. Existing macroscopic models often fail to be predictive without empirical adjustments and a more fundamental approach may be required. We develop a physically-representative, 3D pore network model based on a particle tracking method to simulate particle retention and permeability impairment in polydisperse particle systems. The model includes the effect of hydraulic drag, gravity, electrostatic and van der Waals forces, as well as Brownian motion. A converging-diverging pore throat geometry is used to capture the mechanism of interception. With the analytical solution of fluid velocity within a pore throat, the trajectory of each particle is calculated explicitly. We also incorporate surface roughness and particle-surface interaction to determine particle attachment and detachment. Pore throat structure and conductivity are updated dynamically to account for the effect of deposited particles.Predictions of effluent concentration and macroscopic filtration coefficient are in good agreement with published experimental data. We find that the filtration coefficient is dependent on the relative angle between fluid flow and gravity. Particle deposition by interception is significant for large particle/grain size ratios. Brownian diffusion is the primary cause of retention at low Peclet numbers, especially for small gravity numbers. Particle size distribution is found to be a cause of hyperexponential deposition often observed in experiments. Permeability reduction was small for strong repulsive forces because particles only deposited in paths of slow velocity. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-25T17:15:46.225528-05:
      DOI: 10.1002/aic.15593
       
  • Monte Carlo Real Coded Genetic Algorithm (MC-RGA) for Radioactive Particle
           Tracking (RPT) experimentation
    • Authors: Ashutosh Yadav; Manojkumar Ramteke, Harish J. Pant, Shantanu Roy
      Abstract: Radioactive particle tracking (RPT) technique is a non-invasive velocimetry technique, extensively applied to study hydrodynamics of dense multiphase systems. In this technique, the position of a radioactive tracer particle, designed to mimic the phase of interest, is followed as a Lagrangian marker of point velocity. Computational limitations encountered during tracer particle position reconstruction (which is an inherently slow process) have thus far restricted the use of this versatile technique only to small-scale process vessels. Here, we present a noteworthy improvement over the classical Monte Carlo (MC) algorithm for tracer particle position reconstruction, whereby we enhance the convergence and computational speed of the algorithm using Real Coded Genetic Algorithm (RGA) optimization. This modification results in drastic reduction in computational time required for detector parameter estimation, and altogether eliminates the need for the “distance-count map,” which was earlier inherent to RPT experimentation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-25T17:15:42.57679-05:0
      DOI: 10.1002/aic.15596
       
  • Prediction and Screening of Solubility of Pharmaceuticals in Single- and
           Mixed-Ionic Liquids using COSMO-SAC model
    • Authors: Bong-Seop Lee; Shiang-Tai Lin
      Abstract: In this work, we investigated the prediction of solubility (xd) of drug molecules in single- and mixed-ionic liquid (IL) solutions using the COSMO-SAC activity coefficient model. In particular, the effect of dissociation of IL on solubility is examined. The prediction accuracy is found to be 91% in xd (root-mean-square deviation in ln xd is 0.65) for a total of 442 data points with solubility ranging from 0.93 to 2.84 × 10−4 (mole fraction) and temperature ranging from 248.92 K to 488.3 K. The solubility of drug is found not sensitive to the treatment of dissociation of IL in the calculations. The method is used to determine the solubility of paracetamol in 2,624 single IL made from combination of 82 cations and 32 anions. The solubility of paracetamol can vary by 4 orders of magnitude in different ILs, indicating that this is a powerful method for screening for solvents with desired solubility power. The solubility of a drug in binary IL solution can be significantly higher or lower than those in pure IL components. For the 3,441,376 binary IL mixtures, about 8% of the mixtures exhibit higher solubility for paracetamol and 6% exhibit lower solubility. Our results indicate that mixing ILs can be a viable approach for tuning drug solubility. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-25T17:15:35.362597-05:
      DOI: 10.1002/aic.15595
       
  • Novel Hierarchical Ni/MgO Catalyst for Highly Efficient CO Methanation in
           a Fluidized Bed Reactor
    • Authors: Jun Li; Wencai Peng, Qiang Zhang, Guohua Luo, Qingshan Zhu, Fei Wei
      Abstract: A facile synthesis of the hierarchical Ni/MgO catalyst is reported, with extremely fine dispersion of Ni nanoparticles (NPs) and high surface oxygen mobility. The hierarchical Ni/MgO catalyst exhibits higher activity for CH4 formation than that prepared by the impregnation method. The enhanced activity and thermal stability of the hierarchical Ni/MgO catalyst is attributed to hierarchical MgO particles with a multilayer structure and high surface oxygen mobility. This induces better metal-support interactions, high Ni dispersion to prevent Ni NPs sintering, and the high surface oxygen mobility provides a high resistance to carbon deposition. Compared to the impregnated Ni/MgO catalyst, the hierarchical Ni/MgO catalyst exhibits a better fluidization quality and a higher attrition-resistance in a fluidized-bed reactor. This approach to improve the catalytic activity by creation of hierarchical Ni/MgO particles is encouraging for the design of novel catalysts for SNG production, especially from the perspective of matching catalysts with fluidized-bed reactors. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-25T17:15:30.129488-05:
      DOI: 10.1002/aic.15597
       
  • Linear Model Predictive Control for Transport-Reaction Processes
    • Authors: Qingqing Xu; Stevan Dubljevic
      Abstract: The article deals with systematic development of linear model predictive control algorithms for linear transport-reaction models emerging from chemical engineering practice. The finite-horizon constrained optimal control problems are addressed for the systems varying from the convection dominated models described by hyperbolic PDEs to the diffusion models described by parabolic PDEs. The novelty of the design procedure lies in the fact that spatial discretization and/or any other type of spatial approximation of the process model plant is not considered and the system is completely captured with the proposed Cayley-Tustin transformation, which maps a plant model from a continuous to a discrete state space setting. The issues of optimality and constrained stabilization are addressed within the controller design setting leading to the finite constrained quadratic regulator problem, which is easily realized and is no more computationally intensive than the existing algorithms. The methodology is demonstrated for examples of hyperbolic/parabolic PDEs. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-22T07:10:40.852426-05:
      DOI: 10.1002/aic.15592
       
  • Dynamic properties of a continuous stirred tank biofilm bioreactor for
           aerobic processes
    • Authors: Szymon Skoneczny; Bolesław Tabiś
      Abstract: A dynamic analysis of a continuous stirred tank bioreactor with biofilm was performed. The existence of gas, liquid, and biofilm were taken into account. The proposed heterogeneous model of such bioreactor takes into account dynamic biofilm growth and interphase transfer of substrates and biomass for a double-substrate aerobic process. Simulations were performed to investigate the influence of important process parameters, i.e., toxic substrate concentration in the feed stream, detachment rate coefficient, mean residence time of the liquid and aeration intensity, on dynamic properties of the bioreactor. Dynamic behavior at conditions of anoxia of microorganisms were shown. A method was proposed to reduce bioreactor start-up time significantly. The paper presents a mathematical model of the bioreactor that uses a discrete model of biofilm growth based on the theory of cellular automata. Dynamics of the bioreactor based on the continuous and discrete biofilm model was compared. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-16T03:17:15.393996-05:
      DOI: 10.1002/aic.15591
       
  • Numerical investigation on CO2 absorbed in aqueous
           N-methyldiethanolamine + piperazine
    • Authors: Jicai Huang; Maoqiong Gong, Zhaohu Sun, Xueqiang Dong, Jun Shen, Jianfeng Wu
      Abstract: A multiphase and multicomponent mass transfer model of CO2 absorbed in aqueous N-methyldiethanolamine (MDEA) and piperazine (PZ) was built in the study. In the model, a simple method of mass transfer between phases was proposed. Besides, the hydrodynamics, thermodynamics and complex reversible chemical reaction were considered simultaneously. The model was validated by comparing with the previous experimental data which showed that simulated results can represent the experimental data with reasonable accuracy. Based on the model, the effects of gas velocity, liquid load and CO2 loading on the absorption rate and enhancement factor were analyzed. Model results showed that the enhancement factor increased with a rising gas velocity while decreased with a rising liquid load or CO2 loading. The change of enhancement factor with CO2 loading was similar to that of equilibrium concentration of PZ which indicated that PZ was significant to the absorption process. Furthermore, the distributions of specie concentrations were discussed in detail. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-14T18:52:27.304446-05:
      DOI: 10.1002/aic.15590
       
  • Experimental investigation of gas-liquid flow in monolith channels using
           monofiber optical probes
    • Authors: Deepali Chugh; Jianbin Shao, M.H. Al-Dahhan, Shantanu Roy
      Abstract: Two-phase hydrodynamics has been experimentally investigated by using optical fibre probes in individual channels of a laboratory scale monolith bed. Experimental investigations were carried out to validate the optical probe measurements in a single capillary. Optical probes were positioned at selected single channels of a monolith block, and the signals processed to assess the local hydrodynamics under cocurrent gas-liquid downflow configuration, using air and water as fluids. The investigations were performed for three different distributors, viz. single pipe, multi-pipe, and packed bed distributor configurations. The different distributor configurations were evaluated on the basis of void fraction and bubble frequency for a wide range of flow velocities.The specific novelty aspect of this study comes from the fact that we have undertaken channel scale investigations in monoliths under conditions where we have also reported the global gas-liquid distribution. Thus, one can readily correlate the be-scale hydrodynamics with the local channel-scale hydrodynamics. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-14T18:52:25.201705-05:
      DOI: 10.1002/aic.15586
       
  • Ethylene Glycol Production from Glucose over W-Ru Catalysts: Maximizing
           Yield by Kinetic Modeling and Simulation
    • Authors: Guanhong Zhao; Mingyuan Zheng, Ruiyan Sun, Zhijun Tai, Jifeng Pang, Aiqin Wang, Xiaodong Wang, Tao Zhang
      Abstract: The kinetics of glucose conversion to ethylene glycol (EG) in the presence of ammonium paratungstate and Ru/AC catalysts was studied to model and predict the reaction performance under a range of conditions. A mathematical model was established through the rational simplification of the reaction network on the basis of a continuous stirred-tank model. The kinetic data of six major reactions in the network were experimentally measured, and the analytical expressions of overall reaction kinetics were obtained by introducing the kinetic data to the model. Yields of EG, hexitols and gas were described as functions of the reaction temperature, the concentration of glucose in the feedstock and the feeding rate. The simulation results matched the experimental data of glucose conversion, demonstrating the validity of the model and method for studying the overall kinetics of glucose conversion to EG over W-Ru catalysts. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-14T18:52:22.624493-05:
      DOI: 10.1002/aic.15589
       
  • Group Additive Modeling of Substituent Effects In Monocyclic Aromatic
           Hydrocarbon Radicals
    • Authors: Alper Ince; Hans-Heinrich Carstensen, Maarten Sabbe, Marie-Françoise Reyniers, Guy B. Marin
      Abstract: The thermodynamic properties of the unsubstituted and substituted phenyl, phenoxy, anisyl, benzoyl, styryl and benzyl radicals with six substituents (hydroxy, methoxy, formyl, vinyl, methyl and ethyl) are calculated with the bond additivity corrected (BAC) post-Hartree-Fock G4 method. Bond dissociation energies (BDEs) of monocyclic aromatic hydrocarbons are calculated and used to identify substituent interactions in these radicals. Benson's Group Additivity scheme is extended to aromatic radicals by defining 6 GAV and 29 NNI parameters through least squares regression to a database of thermodynamic properties of 369 radicals. Comparison between G4/BAC and GA calculated thermodynamic values shows that the standard enthalpies of formation generally agree within 4 kJ mol−1, whereas the entropies and the heat capacities deviate less than 4 J mol−1 K−1. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-14T18:51:54.155717-05:
      DOI: 10.1002/aic.15588
       
  • A complete understanding of the reaction kinetics for the industrial
           production process of expandable polystyrene
    • Authors: Lies De Keer; Paul H.M. Van Steenberge, Marie-Françoise Reyniers, Klaus-Dieter Hungenberg, Libor Seda, Dagmar R. D'hooge, Guy B. Marin
      Abstract: For the industrial expandable polystyrene (EPS) process, the Predici software package is successfully applied to demonstrate that the composite kt model is the most appropriate one to accurately account for diffusional limitations on termination. For a broad range of conditions, the reported set of model parameters allows an excellent description of experimental data on monomer conversion and molar mass distribution (MMD). For low temperatures and dicumylperoxide amounts (< 403 K; 
      PubDate: 2016-11-14T18:51:35.930592-05:
      DOI: 10.1002/aic.15587
       
  • Enhanced performance of Rh1/TiO2 catalyst without methanation in water-gas
           shift reaction
    • Authors: Hongling Guan; Jian Lin, Botao Qiao, Shu Miao, Aiqin Wang, Xiaodong Wang, Tao Zhang
      Abstract: Water-gas shift (WGS) reaction is an important process for industrial hydrogen production. The side reaction of methanation often causes unavoidable loss of H2 along with this reaction. Here, we report a Rh1/TiO2 single-atom catalyst (SAC) with appreciable loading of 0.37 wt%, which exhibited an overall CO conversion of ∼95% but without any methanation at 300 oC, even under CO2- and H2-rich WGS stream. The specific activity of this SAC was around four times higher than that of cluster catalyst, which meanwhile suffered from unfavorable methanation. It was found that Rh single atoms promoted the formation of more oxygen vacancies on the TiO2 support to activate H2O to generate H2 and prohibited the dissociation of H2 compared with Rh clusters, leading to the enhanced activity and selectivity for WGS. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-11T18:00:25.388642-05:
      DOI: 10.1002/aic.15585
       
  • Nonlinear time-series analysis of optical signals to identify multiphase
           flow behavior in microchannels
    • Authors: Dongyue Peng; Feng Xin, Lexiang Zhang, Zuopeng Gao, Weihua Zhang, Yuexing Wang, Xiaodong Chen, Yi Wang
      Abstract: The present study provides an insight into the instability and irregularity of multiphase flows in microchannels. Using a homemade optical measuring system, time series related to two-phase flow dynamics under different operating conditions, fluids, and channel lengths were collected and analyzed via a nonlinear characteristic parameter, Kolmogorov entropy (KE). Our results reveal that higher KE corresponds to unstable flow behavior, while lower KE refers to steady flow behavior; higher KE values appear at comparatively low or high gas flow rates, and most Taylor flow regime appeared at proper operating conditions with small KE. An equation derived based on the definition of KE is proposed to better understand KE characteristics, which include bubble break-up impact and gas/liquid flow rate ratio. Predictions from the proposed analytical equation agree with experimental results, suggesting that the equation effectively identifies unstable flows and can be used to ensure stable and predictable multiphase flows in microchannels. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-11T18:00:22.745112-05:
      DOI: 10.1002/aic.15584
       
  • Droplet Formation at Megahertz Frequency
    • Authors: John C. Miers; Wenchao Zhou
      Abstract: Droplet formation has been a fascinating subject to scientists for centuries due to its natural beauty and importance to both scientific and industrial applications, such as inkjet printing, reagent deposition, and spray cooling. However, the droplet generation frequency of common drop-on-demand jetting techniques is mostly limited to ∼10 kHz. This paper presents an investigation of the possibility of jetting at megahertz frequencies in order to boost the productivity of drop-on-demand material deposition by ∼100 times. The focus of this paper is to understand the limitations of generating droplets at a megahertz frequency and to explore possible solutions for overcoming these limitations. A numerical model is first developed for the simulation of droplet formation dynamics. The numerical model is validated against available experimental data from the literature. Aided by insights gained from scaling analysis, the validated model is then used to study the effects of different parameters on high frequency jetting. The study finds energy density input to the nozzle is the key to achieve megahertz frequency droplet breakup. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-11T03:25:24.525323-05:
      DOI: 10.1002/aic.15578
       
  • Simulation of Dry Reforming of Methane in a Conventional Downfired
           Reformer
    • Authors: Yutian R. Zhao; Dean A. Latham, Brant A. Peppley, Kim B. McAuley, Hui Wang, Rick LeHoux
      Abstract: A model for industrial top-fired dry reforming of methane (DRM) and for combined dry reforming and steam reforming of methane was developed for the first time. The model calculates and gives predictions on the temperature profiles for fuel gas, tube walls and process gas, as well as the process gas composition profiles over the length of the tubes. Radiative heat transfer is modeled by Hottel Zone method. Material and energy balances are solved numerically using Newton-Raphson solver. Kinetic models for two different DRM catalysts are applied in the model for comparison. Simulation results show that water-gas shift reaction is important in DRM and addition of steam in the feed of process gas is beneficial for industrial production. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-10T18:10:28.203841-05:
      DOI: 10.1002/aic.15582
       
  • Simulation of Dry Reforming of Methane in a Conventional Downfired
           Reformer
    • Authors: Yutian R. Zhao; Dean A. Latham, Brant A. Peppley, Kim B. McAuley, Hui Wang, Rick LeHoux
      Abstract: A model for industrial top-fired dry reforming of methane (DRM) and for combined dry reforming and steam reforming of methane was developed for the first time. The model calculates and gives predictions on the temperature profiles for fuel gas, tube walls and process gas, as well as the process gas composition profiles over the length of the tubes. Radiative heat transfer is modeled by Hottel Zone method. Material and energy balances are solved numerically using Newton-Raphson solver. Kinetic models for two different DRM catalysts are applied in the model for comparison. Simulation results show that water-gas shift reaction is important in DRM and addition of steam in the feed of process gas is beneficial for industrial production. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-10T18:10:28.203841-05:
      DOI: 10.1002/aic.15582
       
  • Investigation of natural convection heat transfer in a unique scaled-down
           dual-channel facility
    • Authors: Ibrahim A. Said; Mahmoud M. Taha, Shoaib Usman, Brian G. Woods, Muthanna H. Al-Dahhan
      Abstract: Multiphase Reactors Engineering and Applications Laboratory (mReal) has designed and constructed a scaled-down dual-channel facility to investigate plenum-to-plenum natural circulation heat transfer through two channels for coolant flow that would be encountered during a loss of flow accident in the prismatic modular reactor (PMR). Heat transfer characterization of the current facility has been investigated under different upper plenum and cooled channel outer surface temperatures using sophisticated flush mounted heat transfer sensors. Results show a reduction in the values of local heat transfer coefficient and Nusselt number along the heated channel with increasing outer surface temperatures. One significant observation was the heat transfer reversal close to heated channel exit, where the heat flows from gas to the channel wall. This flow reversal is attributed to recirculation at the heated channel exit to the upper plenum. The average heat transfer results, when compared with previous literature, showed a similar qualitative trend. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-10T18:00:27.430544-05:
      DOI: 10.1002/aic.15583
       
  • Investigation of natural convection heat transfer in a unique scaled-down
           dual-channel facility
    • Authors: Ibrahim A. Said; Mahmoud M. Taha, Shoaib Usman, Brian G. Woods, Muthanna H. Al-Dahhan
      Abstract: Multiphase Reactors Engineering and Applications Laboratory (mReal) has designed and constructed a scaled-down dual-channel facility to investigate plenum-to-plenum natural circulation heat transfer through two channels for coolant flow that would be encountered during a loss of flow accident in the prismatic modular reactor (PMR). Heat transfer characterization of the current facility has been investigated under different upper plenum and cooled channel outer surface temperatures using sophisticated flush mounted heat transfer sensors. Results show a reduction in the values of local heat transfer coefficient and Nusselt number along the heated channel with increasing outer surface temperatures. One significant observation was the heat transfer reversal close to heated channel exit, where the heat flows from gas to the channel wall. This flow reversal is attributed to recirculation at the heated channel exit to the upper plenum. The average heat transfer results, when compared with previous literature, showed a similar qualitative trend. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-10T18:00:27.430544-05:
      DOI: 10.1002/aic.15583
       
  • Simultaneous recovery and crystallization control of saline organic
           wastewater by membrane distillation crystallization
    • Authors: Dapeng Lu; Pan Li, Wu Xiao, Gaohong He, Xiaobin Jiang
      Abstract: In this article, membrane distillation crystallization (MDC) was introduced and investigated for the simultaneous treatment of saline organic wastewater generated from oil extraction. The developed process model of MDC for the investigated ternary system was validated by the experiments with good agreement. Under the tested feed ethylene glycol (EG) composition and operation conditions, the highly concentrated EG (residual side, recovery ratio>98.7%), pure water (permeate side, purity>99%), pure crystals with narrow crystal size distribution and desired morphology were simultaneously manufactured. By this simultaneous recovery of EG and H2O in the feed flow, the overall separation efficiency was enhanced. The impact factors of the crystal properties during MDC were also revealed by comprehensive analysis. Moreover, the diverse metastable zone width and crystal morphology obtained in different feed EG composition indicated the change of the nucleation barrier and the kinetic crystallization control mechanism. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-10T18:00:25.999039-05:
      DOI: 10.1002/aic.15581
       
  • Simultaneous recovery and crystallization control of saline organic
           wastewater by membrane distillation crystallization
    • Authors: Dapeng Lu; Pan Li, Wu Xiao, Gaohong He, Xiaobin Jiang
      Abstract: In this article, membrane distillation crystallization (MDC) was introduced and investigated for the simultaneous treatment of saline organic wastewater generated from oil extraction. The developed process model of MDC for the investigated ternary system was validated by the experiments with good agreement. Under the tested feed ethylene glycol (EG) composition and operation conditions, the highly concentrated EG (residual side, recovery ratio>98.7%), pure water (permeate side, purity>99%), pure crystals with narrow crystal size distribution and desired morphology were simultaneously manufactured. By this simultaneous recovery of EG and H2O in the feed flow, the overall separation efficiency was enhanced. The impact factors of the crystal properties during MDC were also revealed by comprehensive analysis. Moreover, the diverse metastable zone width and crystal morphology obtained in different feed EG composition indicated the change of the nucleation barrier and the kinetic crystallization control mechanism. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-10T18:00:25.999039-05:
      DOI: 10.1002/aic.15581
       
  • Preface to Special Issue
    • Authors: Dan Hickman; Aditya Bhan, Paul Dauenhauer, Michael P. Harold
      PubDate: 2016-11-10T03:55:22.290352-05:
      DOI: 10.1002/aic.15576
       
  • What is the leanest stream to sustain a nonadiabatic loop reactor:
           Analysis and methane combustion experiments
    • Authors: A. Y. Madai; O. Nekhamkina, M. Sheintuch
      Abstract: While previous studies experimentally demonstrated that loop reactor (LR) can be sustained with a lean feed (using ethylene combustion) and have analyzed the single-reaction adiabatic case, this work analyzes the effects of heat loss and of reactor size to determine the leanest stream (expressed in terms of adiabatic temperature rise ΔTlim) that will sustain the operation. For an adiabatic infinitely long reactor ΔTlim0 while for a finite reactor ΔTlim scales as (1+Pe/4)−1 where Pe=Luρcpf/k, and heat loss increases this limit by (β/Pe)1/2. Thus, a good design of a LR will aim to decrease conductivity (k) and radial heat transfer coefficient (β) while increasing throughput (u) and reactor length. This article is also the first experimental demonstration of auto-thermal operation in a LR for catalytic abatement of low-concentration of methane, showing the leanest stream to be of 8000 ppm vs 33000 ppm in a once-through reactor. Experimental combustion results of methane and of ethylene are compared with model predictions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-09T18:01:06.518653-05:
      DOI: 10.1002/aic.15580
       
  • Kinetic Study of Methane Reforming with Carbon Dioxide over NiCeMgAl
           Bimodal Pore Catalyst
    • Authors: Zhenghong Bao; Yongwu Lu, Fei Yu
      Abstract: The kinetic behavior of NiCeMgAl bimodal pore catalyst for methane reforming with CO2 was investigated after the elimination of external and internal diffusion effects in a fixed-bed reactor as a function of temperature and partial pressures of reactants and products. Increase in CO2 partial pressure favors the consumptions of CH4 and CO2 but inhibits the formation of H2 due to the existence of reverse water gas shift (RWGS) reaction. The reforming rate increased first and then reached a horizontal stage with the rise of CH4 partial pressure. A Langmuir-Hinshelwood model was developed assuming that the carbon deposition is ignorable but the RWGS reaction is non-ignorable and the removal of adsorbed carbon intermediate is the rate-determining step. A nonlinear least-square method was applied to solve the kinetic parameters. The derived kinetic expression fits the experimental data very well with a R2 above 0.97, and also predicts the products flow rate satisfactorily. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-09T18:01:01.516139-05:
      DOI: 10.1002/aic.15579
       
  • 8An Adaptive Parallel Tempering Method for the Dynamic Data-Driven
           Parameter Estimation of Nonlinear Models
    • Authors: Matthew J. Armstrong; Antony N. Beris, Norman J. Wagner
      Abstract: An adaptive parallel tempering algorithm is developed in a user-friendly fashion that efficiently and robustly generates near-optimum solutions. Using adaptive, implicit, time-integration methods, the method allows fitting model parameters to dynamic data. The proposed approach is relatively insensitive to the initial guess and requires minimal fine-tuning: most of the algorithm parameters can be determined adaptively based on the analysis of few model simulations, while default values are proposed for the few remaining ones, the exact values of which do not sensitively affect the solution. The method is extensively validated through its application to a number of algebraic and dynamic global optimization problems from Chemical Engineering literature. We then apply it to a multi-parameter, highly nonlinear, model of the rheology of a thixotropic system where we show how the present approach can be used to robustly determine model parameters by fitting to dynamic, large amplitude, oscillatory stress vs. shear rate, data. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-08T09:55:38.933361-05:
      DOI: 10.1002/aic.15577
       
  • Modifying the inter-phase drag via solid volume fraction gradient for CFD
           simulation of fast fluidized beds
    • Authors: Mingze Su; Haibo Zhao
      Abstract: The conventional drag model in two-fluid simulation, which assumes uniform particle distribution in a computational grid, overestimates the drag force, thus failed in capturing the subgrid-scale strands and resolvable-scale clusters. This work proposed a new modification to the conventional drag model through considering the heterogeneous distribution of solid volume fraction, especially, in the inter-phase boundary (i.e., cluster boundary). The resulting drag model is a function of particle Reynolds number, solid volume fraction and the gradient of solid volume fraction. This straightforward modification is consistent with the elaborately filtered-approach-based modification method in nature. A CFD simulation for a two-dimensional riser was conducted to validate the new drag model. The outlet solid mass flux, axial and radial time-averaged voidages from the new drag model agreed well with the experimental measurements, and these results were far better than those from the conventional homogeneous drag models. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-08T04:12:46.301185-05:
      DOI: 10.1002/aic.15573
       
  • A constitutive equation for thixotropic suspensions with yield stress by
           coarse-graining a population balance model
    • Authors: Paul M. Mwasame; Antony N. Beris, R. B. Diemer, Norman J. Wagner
      Abstract: A population balance model appropriate for the shear flow of thixotropic colloidal suspensions with yield stress is derived and tested against experimental data on a model system available in the literature. Modifications are made to account for dynamic arrest at the onset of the yield stress, in addition to enforcing a minimum particle size below which breakage is not feasible. The resulting constitutive model also incorporates a structural based relaxation time, unlike existing phenomenological models that use the inverse of the material shear rate as the relaxation time. The model provides a reasonable representation of experimental data for a model thixotropic suspension in the literature, capturing the important thixotropic timescales. When compared to prevalent structure kinetics models, the coarse grained population balance equation is shown to be distinct, emphasizing the novelty of utilizing population balances as a basis for thixotropic suspension modeling. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-08T04:12:18.222496-05:
      DOI: 10.1002/aic.15574
       
  • Catalytic Oxidation of Solid Carbon and Carbon Monoxide over
           Cerium-Zirconium Mixed Oxides
    • Authors: Kehua Yin; Shilpa Mahamulkar, Hirokazu Shibata, Andrzej Malek, Christopher W. Jones, Pradeep Agrawal, Robert J. Davis
      Abstract: A series of cerium-zirconium mixed oxides was prepared and evaluated in the catalytic oxidation of solid coke with 10 vol.% O2 in He at 673 K using a thermogravimetric analyzer. The measured first order rate constant for coke oxidation was proportional to the catalyst loading when the mass ratio of catalyst to coke was low, which enabled the calculation of a surface area specific reaction rate. The validity of the normalization method was confirmed by performing CO oxidation over the cerium-zirconium mixed oxides in a fixed bed reactor at 573 K. Although there was no correlation between the coke oxidation rate and the oxygen storage capacity or the reducibility of the catalysts, there was an excellent correlation to the CO oxidation rate. Kinetic studies of both coke and CO oxidation suggested an important role of surface lattice oxygen from the catalyst in the two reactions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-08T04:10:47.189136-05:
      DOI: 10.1002/aic.15575
       
  • Turbulent Mixing in the Confined Swirling Flow of a Multi-Inlet Vortex
           Reactor
    • Authors: Zhenping Liu; Emmanuel Hitimana, James C. Hill, Rodney O. Fox, Michael G. Olsen
      Abstract: Turbulent mixing in the confined swirling flow of a multi-inlet vortex reactor (MIVR) was investigated using planar laser induced fluorescence (PLIF). The investigated Reynolds numbers based on the bulk inlet velocity ranged from 3290 to 8225, and the Schmidt number of the passive scalar was 1250. Measurements were taken in the MIVR at three different heights (¼, ½ and ¾ planes). The mixing characteristics and performance of the MIVR were investigated using instantaneous PLIF fields and pointwise statistics such as mixture fraction mean, variance, and one-point concentration probability density function (PDF). It was found that the scalar is stretched along velocity streamlines, forming a spiral mixing pattern in the free-vortex region. In the forced-vortex region, mixing intensifies as the turbulent fluctuations increase significantly there. The mixing mechanisms in the MIVR were revealed by identifying specific segregation zones. At Re=8225 the mixing in the free-vortex region was dominated by both large-scale structures and turbulent diffusion, while in the forced-vortex region mixing is dominated by turbulent diffusion. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-08T04:10:41.84289-05:0
      DOI: 10.1002/aic.15572
       
  • Investigating the liquid film characteristics of gas-liquid swirling flow
           using ultrasound Doppler velocimetry
    • Authors: Fachun Liang; Zhaojun Fang, Jing Chen, Shitao Sun
      Abstract: A novel gas-liquid two-phase flow metering method was proposed. A spiral vane mounted in the inner pipe was used to transform inlet flow patterns into gas-liquid swirling annular flow. The thickness and velocity profile of liquid film were measured by ultrasound Doppler velocimetry(UDV). The liquid flow rates were obtained by integrating of velocity profile during the liquid film zone. Experiments were carried out in an air-water two-phase flow loop and an ultrasonic transducer was installed under the bottom of the test section with the Doppler angle of 70°. The flow patterns included stratified wavy, annular and slug flows. Compared with non-swirling flow, the liquid film thickness at the bottom reduces greatly. The measurement accuracy of liquid flow rate was independent of inlet flow patterns, gas and liquid velocities. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-07T10:47:55.293986-05:
      DOI: 10.1002/aic.15570
       
  • Investigating the liquid film characteristics of gas-liquid swirling flow
           using ultrasound Doppler velocimetry
    • Authors: Fachun Liang; Zhaojun Fang, Jing Chen, Shitao Sun
      Abstract: A novel gas-liquid two-phase flow metering method was proposed. A spiral vane mounted in the inner pipe was used to transform inlet flow patterns into gas-liquid swirling annular flow. The thickness and velocity profile of liquid film were measured by ultrasound Doppler velocimetry(UDV). The liquid flow rates were obtained by integrating of velocity profile during the liquid film zone. Experiments were carried out in an air-water two-phase flow loop and an ultrasonic transducer was installed under the bottom of the test section with the Doppler angle of 70°. The flow patterns included stratified wavy, annular and slug flows. Compared with non-swirling flow, the liquid film thickness at the bottom reduces greatly. The measurement accuracy of liquid flow rate was independent of inlet flow patterns, gas and liquid velocities. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-07T10:47:55.293986-05:
      DOI: 10.1002/aic.15570
       
  • Investigation of the Effect of Magnetic Field on Mass Transfer Parameters
           of CO2 Absorption Using Fe3O4-Water Nanofluid
    • Authors: Mohammad Hossein Karimi Darvanjooghi; Maedeh Pahlevaninezhad, Ali Abdollahi, Seyyed Mohammadreza Davoodi
      Abstract: In this study, the enhancement of physical absorption of carbon dioxide by Fe3O4-water nanofluid under the influence of AC and DC magnetic fields was investigated. Furthermore, a gas-liquid mass transfer model for single bubble systems was applied to predict mass transfer parameters. The coated Fe3O4 nanoparticles were prepared using co-percipitation method. The results from characterization indicated that the nanoparticles surfaces were covered with hydroxyl groups and nanoparticles diameter were 10-13 nm. The findings showed that the mass transfer rate and solubility of carbon dioxide in magnetic nanofluid increased with an increase in the magnetic field strength. results indicated that the enhancement of carbon dioxide solubility and average molar flux gas into liquid phase, particularly in the case of AC magnetic field. Moreover, results demonstrated that mass diffusivity of CO2 in nanofluid and renewal surface factor increased when the intensity of the field increased and consequently diffusion layer thickness decreased. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-05T09:52:53.199652-05:
      DOI: 10.1002/aic.15571
       
  • Investigation of the Effect of Magnetic Field on Mass Transfer Parameters
           of CO2 Absorption Using Fe3O4-Water Nanofluid
    • Authors: Mohammad Hossein Karimi Darvanjooghi; Maedeh Pahlevaninezhad, Ali Abdollahi, Seyyed Mohammadreza Davoodi
      Abstract: In this study, the enhancement of physical absorption of carbon dioxide by Fe3O4-water nanofluid under the influence of AC and DC magnetic fields was investigated. Furthermore, a gas-liquid mass transfer model for single bubble systems was applied to predict mass transfer parameters. The coated Fe3O4 nanoparticles were prepared using co-percipitation method. The results from characterization indicated that the nanoparticles surfaces were covered with hydroxyl groups and nanoparticles diameter were 10-13 nm. The findings showed that the mass transfer rate and solubility of carbon dioxide in magnetic nanofluid increased with an increase in the magnetic field strength. results indicated that the enhancement of carbon dioxide solubility and average molar flux gas into liquid phase, particularly in the case of AC magnetic field. Moreover, results demonstrated that mass diffusivity of CO2 in nanofluid and renewal surface factor increased when the intensity of the field increased and consequently diffusion layer thickness decreased. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-05T09:52:53.199652-05:
      DOI: 10.1002/aic.15571
       
  • Issue information
    • Abstract: Cover illustration. Active learning in the classroom using student response systems. (Credit for cover: http://creativecommons.org/) 10.1002/aic.15387
      PubDate: 2016-11-03T18:24:58.269407-05:
      DOI: 10.1002/aic.15003
       
  • Bifurcation Analysis of Index Infinity DAE Parabolic Models Describing
           Reactors and Reacting Flows
    • Authors: Ram R. Ratnakar; Vemuri Balakotaiah
      Abstract: We show that most steady-state models of chemical reactors and reacting flows in which convection effects are dominant and diffusion/conduction is neglected in the flow direction but included in the transverse directions, may change from parabolic type with a unique solution to index infinity differential-algebraic equation (DAE) type with an infinite number of steady-state solutions depending on the values of the reaction parameters. When a model is of index infinity, standard numerical methods may find only one of the solutions corresponding to latest possible ignition. We present complete bifurcation analysis of these models, a method for finding all solutions, determine the stability and, for some simpler cases, the domain of initial conditions attracted to these states. We also demonstrate that the various steady-state solutions of the DAE systems are best found by integrating the transient hyperbolic versions of the models with appropriately selected capacitance terms and initial conditions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-03T18:12:58.62714-05:0
      DOI: 10.1002/aic.15568
       
  • Hydrodynamic Drift Ratchet Scalability
    • Authors: J. W. Herringer; D. Lester, G. E. Dorrington, J. G. Mitchell, G. Rosengarten
      Abstract: The hydrodynamic drift ratchet provides a novel means to continuously separate particles at the micro-scale, based on particle size. Separation arises from a combination of diffusion and particle-wall hydrodynamic interactions. As there are currently no verified experiments, our aim is to determine numerically how these systems scale so that appropriate experiments can be designed. Using non-dimensional variables, we demonstrate correct scaling parameters governing drift ratchets by simulating individual particle motion using a model that treats the particle dynamics at pore walls as elastic reflections. Whilst our model does not quantitatively resolve the detailed hydrodynamic interactions, we show that it does recover the correct scaling behaviour for these interactions. Our simulations demonstrate that the drift velocity relative to the characteristic pore size is independent of pore size if all the relevant non-dimensional groups remain constant. Dynamic similarity can be used to facilitate the appropriate design and testing protocols for experiments. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-03T18:09:36.434736-05:
      DOI: 10.1002/aic.15569
       
  • On the 2D nature of flow dynamics in opposed jets mixers
    • Authors: N. D. Gonçalves; H. M. Salvador, C. P. Fonte, M. M. Dias, J. C. B. Lopes, R. J. Santos
      Abstract: Confined impinging jets (CIJs) are reactors used in processes that require fast mixing. In such equipment two fluids are injected from opposite sides of a chamber, impinging into each other and forming flow structures that enable an effective mixing and reaction. The turbulence analysis shows that the energy is injected from smaller scales, having approximately the injectors width, that feed larger scale structures up to larger vortices that occupy the entire mixing chamber width. This energy distribution has an inverse energy cascade, i. e. it is an inversion of the traditional description of homogeneous 3D turbulence. The typical flow scales of 2D CIJs are clearly shown in this work to be linked to the 2D turbulence energy spectrum and to integral scales of turbulence. Moreover, the turbulence mechanisms in 3D CIJs at transitional flow regimes are shown to be similar to 2D CIJs. This is to our knowledge the first demonstration of 2D turbulence in an industrial mixer/reactor. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-02T18:15:30.36792-05:0
      DOI: 10.1002/aic.15566
       
  • Application of the compartmental model to the gas-liquid precipitation of
           CO2-Ca(OH)2 aqueous system in a stirred tank
    • Authors: Wenli Zhao; Antonio Buffo, Ville Alopaeus, Bing Han, Marjatta Louhi-Kultanen
      Abstract: A compartmental model is formulated to assess the influence of fluid dynamics on the gas-liquid precipitation of CO2(g)-Ca(OH)2(aq) system in a stirred tank reactor. The model combines the description of the flow field with several sub-models, namely gas to liquid mass transfer, chemical reaction, precipitation and population balance for both gas bubbles and solid crystals. The modeling predictions, including the average volumetric mass transfer coefficient, the concentration of calcium ions, the pH of the solution and the Sauter mean diameter of the final crystal products are eventually compared with measurements carried out on a pilot-scale stirred tank. The results show that the local volumetric mass transfer rate and the final particle sizes distribution of the crystals are significantly affected by high local turbulence near the impeller. The local information simulated by the compartmental model, such as mass transfer rate, gas hold up and particle size of crystals and bubbles are important for the design and scaling of gas-liquid precipitators, with a computational time which is of several orders of magnitude faster than a full CFD computation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-02T18:10:36.492487-05:
      DOI: 10.1002/aic.15567
       
  • Dynamic Models and Fault Diagnosis-Based Triggers for Closed-Loop
           Scheduling
    • Authors: Cara R. Touretzky; Iiro Harjunkoski, Michael Baldea
      Abstract: Establishing an explicit feedback connection between production management and process control decisions is a key requirement for more nimble and cost effective process operations in today's variable market conditions. Past research efforts focused on embedding dynamic process information in the production scheduling problem. In this paper, we propose a novel framework for closing the scheduling loop, based on considering the process-level events and disturbances that impact the implementation of scheduling decisions. We emphasize the role of a comprehensive fault detection, isolation and reconstruction mechanism as a trigger for rescheduling decisions and for reflecting the process capabilities altered by these events in the rescheduling problem formulation. Our framework is agnostic to the process type, and we present two (continuous process, sequential batch process) case studies to demonstrate its applicability. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-02T18:10:32.288557-05:
      DOI: 10.1002/aic.15564
       
  • Experimental investigation of interfacial mass transfer mechanisms for a
           confined high-Reynolds-number bubble rising in a thin gap
    • Authors: Matthieu Roudet; Anne-Marie Billet, Sébastien Cazin, Frédéric Risso, Véronique Roig
      Abstract: Interfacial mass transfer is known to be enhanced for confined bubbles due to the efficiency of the transfer in the thin liquid films between them and the wall. In the present experimental investigation, the mechanisms of gas-liquid mass transfer are studied for isolated bubbles rising at high Reynolds number in a thin gap. A PLIF technique is applied with a dye the fluorescence of which is quenched by dissolved oxygen. The aim is to measure the interfacial mass fluxes for pure oxygen bubbles of various shapes and paths rising in water at rest. In the wakes of the bubbles, patterns due to the presence of dissolved oxygen are observed on PLIF images. They reveal the contrasted contributions to mass transfer of two different regions of the interface. The flow around a bubble consists of both two thin liquid films between the bubble and the walls of the cell and an external high-Reynolds-number in-plane flow surrounding the bubble. Mass transfer mechanisms associated to both regions are discussed. Measurement of the concentration of dissolved oxygen is a difficult task due to the non-linear relation between the fluorescence intensity and the concentration in the gap. It is however possible to accurately measure the global mass flux transferred through the bubble interface. It is determined from the fluorescence intensity recorded in the wakes when the oxygen distribution has been made homogeneous through the gap by diffusion. Assuming a reasonable distribution of oxygen concentration through the gap at short time also allows a measurement of the mass fluxes due to the liquid films. A discussion of the results points out the specific physics of mass transfer for bubbles confined between two plates as compared to bubbles free to move in unconfined flows. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-02T18:06:01.623875-05:
      DOI: 10.1002/aic.15562
       
  • Continuous-time Scheduling Formulation for Straight Pipelines
    • Authors: Hossein Mostafaei; Pedro M. Castro
      Abstract: Pipelines represent the most cost-effective way of transporting large quantities of refined petroleum products over large distances but can be challenging to operate. In this paper, we propose a new mixed-integer linear programming (MILP) formulation for scheduling straight pipelines with multiple single and dual purpose nodes. The model allows for simultaneous injections and deliveries, and interacting pumping runs, in which a segment of the pipeline simultaneously receives material from its refinery and upstream segment. In contrast to previous batch centric models, it uses segment dependent coordinates. To make it efficient by design, we rely on Generalized Disjunctive Programming and develop disjunctions for which the convex hull reformulation is simple (roughly the same number of variables and constraints as its big-M counterpart). Through the solution of a set of test cases from the literature, we show a better utilization of the pipeline capacity that is translated into a lower makespan. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-02T18:05:45.959034-05:
      DOI: 10.1002/aic.15563
       
  • Modeling and Analysis of the Lurgi-Type Methanol to Propylene Process:
           Optimization of Olefin Recycle
    • Authors: Xun Huang; Hu Li, Hui Li, Wen-De Xiao
      Abstract: This work proposed a strategy to improve the yield of light olefins of industrial methanol to propylene process by reducing the olefins recycled back into the main reactor and appending an olefin cracking reactor. The heterogeneous fixed-bed model was employed to simulate the reactors with a robust mathematical procedure developed to determine the reactor configuration and the recycle flowrates of the olefins. Two methods were proposed for the modulation: the recycle ratio and species of the olefins, respectively. Results show that the yield of C2-C3 olefins can be improved up to 70% from the basement of about 60% when the ratio is reduced from 100% to less than 23% or when only butene apart from pentene and hexene is recycled back into the main reactor, and the latter method is more effective as its catalyst requirement is seven times less than the former's in the appended cracking reactor. This article is protected by copyright. All rights reserved.
      PubDate: 2016-11-02T18:05:41.648584-05:
      DOI: 10.1002/aic.15565
       
  • Efficient Adsorption Separation of Acetylene and Ethylene via Supported
           Ionic Liquid on Metal-Organic Framework
    • Authors: Jiawei Wang; Danyan Xie, Zhiguo Zhang, Qiwei Yang, Huabin Xing, Yiwen Yang, Qilong Ren, Zongbi Bao
      Abstract: Ionic liquid (IL) supported metal-organic framework (MOF) was utilized to efficiently separate acetylene from ethylene. A common ionic liquid, 1-butyl-3-methylimidazolium acetate ([Bmim][OAc]), was encapsulated into a hydrothermally stable MOF, namely MIL-101(Cr). Characterization techniques including FTIR, PXRD, BET, and TGA were used to confirm successful encapsulation of the IL within MIL-101(Cr). Adsorption isotherms of acetylene and ethylene in the IL-encapsulated MOF were tested. From the results, the MOF composite retained a relatively high adsorption capacity. Remarkably, the adsorption selectivity of acetylene/ethylene has dramatically increased from 3.0 to 30 in comparison with the parent MIL-101(Cr). Furthermore, the potential of industrial practice was examined by breakthrough and regeneration experiments. It not only satisfies the industrial production of removal of low level of acetylene from ethylene, but also is notably stable during the adsorption-desorption process. The high designability of ILs combined with richness of MOFs' structures exploits a novel blueprint for gas separation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-27T03:40:33.841907-05:
      DOI: 10.1002/aic.15561
       
  • New Development in Flow-Through Pressure-Swing Frequency Response Method
           for Mass Transfer Study: Ethane in ZIF-8
    • Authors: Yu Wang; Charanjit Paur, Peter I. Ravikovitch
      Abstract: A new pressure-swing frequency response (PSFR) method has been developed to study mass transfer in adsorption systems as a function of temperature and pressure, from -70 to 180 ºC, and up to 7 bar. New in-phase and out-of-phase functions have been derived for the PSFR in a general way to allow information extracted from it independent of whether the system is operated in a batch volume swing or a flow-through pressure swing mode. A new mathematical model that considers distribution of diffusion rates has been introduced to account for diffusive transport in heterogeneous samples. Numerical simulation results have shown that a single rate diffusion model works well when heterogeneity can be described by a normal distribution, but not those with asymmetrically bimodal distributions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-25T08:05:26.445124-05:
      DOI: 10.1002/aic.15560
       
  • Steady Flow of Gas and Decomposing Particles in a Vertical Feed Tube for
           Applications in Biomass Pyrolysis
    • Authors: Yenhan Lin; Triantafillos J. Mountziaris, Jeffrey M. Davis
      Abstract: Using the approach of interacting and interpenetrating continua, a one-dimensional model is developed for the gravity-driven flow of particles and gas through a vertical standpipe. The gas and particle phases exchange momentum through the drag force, and mass is exchanged between the phases as the particles decompose to gaseous products. Upon simultaneously integrating the differential equations expressing conservation of mass and momentum for each of the two phases, the theory yields the particle and gas flow rates, the pressure profile, and the particle size and void fraction distributions. Performance diagrams are constructed, and preferred operating conditions are identified that provide steady flow, generate no backpressure, or avoid a transition to moving bed flow or reversed gas flow. The admissible range of operating conditions is found to increase with the particle decomposition rate, and the results may guide the selection of operating conditions in practice. Applications are made to biomass pyrolysis in a catalytic reactor. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-25T07:55:48.91933-05:0
      DOI: 10.1002/aic.15558
       
  • Radiotracer and Particle Tracking Methods, Modeling and Scale-Up
    • Authors: Shantanu Roy
      Abstract: Radiotracer techniques are widely used for troubleshooting and detection of pathological flows in industrial reactors. In recent decades, there has been a trend towards using radiotracer techniques for assessing flow field in industrial vessels, likening them to residence time distribution (RTD) measurements. On the other hand, radiation-based particle tracking techniques such as Radioactive Particle Tracking (RPT) methods have become popular for laboratory investigations flow fields in multiphase reactors. Both the methods have been used to validate respective-scale phenomenological and CFD models to some success, but in a rather independent and ad hoc fashion and not attempting to link the two techniques as flow interrogators in their respective domains. This communication tries to bridge these two techniques and proposes a way to link the two, and makes a case for using them as complementary techniques for measurements at the two scales, and for validating models at the two scales. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-25T07:55:44.33592-05:0
      DOI: 10.1002/aic.15559
       
  • Droplet breakage and coalescence in liquid-liquid dispersions: comparison
           of different kernels with EQMOM and QMOM
    • Authors: Dongyue Li; Antonio Buffo, Wioletta Podgorska, Zhengming Gao, Daniele L. Marchisio
      Abstract: Droplet coalescence and breakage in turbulent liquid-liquid dispersions is simulated by using computational fluid dynamics (CFD) and population balance modeling (PBM). The multifractal (MF) formalism that takes into account internal intermittency was here used for the first time to describe breakage and coalescence in a surfactant-free dispersion. The log-normal Extended Quadrature Method of Moments (EQMOM) was for the first time coupled with a CFD multiphase solver. To assess the accuracy of the model, predictions are compared with experiments and other models (i.e., Coulalogou and Tavlarides kernels and Quadrature Method of Moments, QMOM). EQMOM and QMOM resulted in similar predictions, but EQMOM provides a continuous reconstruction of the droplet size distribution. Transient predictions obtained with the MF kernels result in a better agreement with the experiments. This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-24T03:31:59.027503-05:
      DOI: 10.1002/aic.15557
       
  • Shell and Tube Heat Exchanger Design Using Mixed-Integer Linear
           Programming
    • 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
           Condition
    • 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
           tiles
    • 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
       
  • 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
       
  • Cyclic mass transport phenomena in a novel reactor for gas-liquid-solid
           contacting
    • 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
       
  • Periodic reactive flow simulation: Proof of concept for steam cracking
           coils
    • 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
       
  • 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
       
  • 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
       
  • 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
       
  • Controlling three dimensional ice template via two dimensional surface
           wetting
    • 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
       
  • 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
       
  • Issue information - table of contents
    • Pages: 4173 - 4173
      PubDate: 2016-11-03T18:24:58.187513-05:
      DOI: 10.1002/aic.15002
       
  • Why not try active learning?
    • Authors: John L. Falconer
      Pages: 4174 - 4181
      PubDate: 2016-07-13T10:17:47.832956-05:
      DOI: 10.1002/aic.15387
       
  • A novel consolidation method to measure powder flow properties using a
           small amount of material
    • Authors: Sara Koynov; Fernando J. Muzzio, Benjamin J. Glasser
      Pages: 4193 - 4200
      Abstract: Bulk flow property characterization often requires large powder samples (tens to hundreds of grams). However, many applications have limited sample availability, due to cost, material availability, safety concerns, etc. Therefore, reducing the amount of required material is of interest. A novel compressibility method is introduced using less than 50 mg, for the materials studied here. The effect of particle size and cohesion due to capillary forces are determined using a small-scale compressibility cell mounted on a texture analyzer. It is found that the powder bed consolidation occurred in two regimes, described using the Walker and Heckel equations. The small-scale compressibility method was compared to known behavior at larger scales and validated against the FT4 compressibility test. It was found that bulk behavior could be observed using the small-scale compressibility method. Additional behavior caused by small-scale events, which are averaged out in large-scale measurements, are revealed in the small-scale device introduced here. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4193–4200, 2016
      PubDate: 2016-06-03T09:21:55.573467-05:
      DOI: 10.1002/aic.15321
       
  • Improving dissolution kinetics of pharmaceuticals by fluidized bed
           impregnation of active pharmaceutical ingredients
    • Authors: Plamen I. Grigorov; Benjamin J. Glasser, Fernando J. Muzzio
      Pages: 4201 - 4214
      Abstract: Investigational drugs are increasingly becoming less soluble in aqueous media, thus, presenting real challenges during development. Previous work has successfully demonstrated the manufacturing of pharmaceuticals using fluidized bed (FB) impregnation of APIs onto porous carriers. This study demonstrates the usefulness of FB impregnation in formulating poorly soluble drugs. We show that dissolution of Fenofibrate is greatly improved by FB impregnation onto Neusilin® (Fuji Health Science Inc, Burlington, NJ USA), a synthetic amorphous form of magnesium alumino-metasilicate. We impregnate Neusilin® for range of loadings and examine Fenofibrate's physical state. Dissolution of impregnated formulations is drug loading dependent and loadings below 40% show great improvement (decrease) in release time compared to physical blend. Release times are further improved by milling. We also examine feasibility of coimpregnating Fenofibrate with additives and observe stability (1.5 years) of the amorphous form of Fenofibrate inside Neusilin®. This stabilization significantly improves Fenofibrate's dissolution kinetics, making our formulation comparable to one of the current market formulations, TriCor® tablets (AbbVie Inc, North Chicago, IL USA). © 2016 American Institute of Chemical Engineers AIChE J, 62: 4201–4214, 2016
      PubDate: 2016-06-08T10:45:30.92045-05:0
      DOI: 10.1002/aic.15312
       
  • Chord length distribution to particle size distribution
    • Authors: Ajinkya V. Pandit; Vivek V. Ranade
      Pages: 4215 - 4228
      Abstract: A simple model is presented to extract the particle size distribution (PSD) from the chord length distribution measured using a focused beam reflectance measurement probe. The model can be implemented using simple spread sheeting tools and does not require the description of additional parameters as opposed to previous models. The model was validated for two systems consisting of spherical ceramic beads by comparing model predicted PSD against the PSD obtained through image analysis (IA). Then, the model was evaluated by considering various systems consisting of irregularly shaped particles (sand/zinc dust/plasma alumina). Model predictions accurately predicted the mean but over-predicted the variance of the PSD in comparison with the PSD obtained from IA. However, overall, a reasonable agreement was observed. Finally, the model was shown to be accurate in predicting PSD in comparison with the measured PSD for systems of practical relevance such as for paracetamol and p-aminophenol crystals. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4215–4228, 2016
      PubDate: 2016-06-09T10:31:06.656254-05:
      DOI: 10.1002/aic.15338
       
  • Viscosity and drop size evolution during suspension polymerization
    • Authors: Michal Vonka; Miroslav Soos, Giuseppe Storti
      Pages: 4229 - 4239
      Abstract: Annually, suspension polymerization produces kilotons of material with properties given by process conditions. The prediction of material properties requires a relevant description of processes on various scales from the molecular level to reactor design. The polymerization occurring on the molecular scale was described by a kinetic scheme of homopolymerization. The molecular level was connected to the meso-scale by the viscosity evolution inside a single monomer/polymer drop. The viscosity model follows the change in the reaction mixture composition and its predictions were validated by the rheology measurements. During the suspension polymerization, the viscosity evolution affects the dispersion breakage and coalescence on the meso-scale, which is closely connected to the flow conditions given by the reactor design and operation conditions. This complex problem was described by a coupled CFD-PBE model. The presented study proposes a modeling approach to control the suspension polymerization by stirring speed to obtain the desired drop size. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4229–4239, 2016
      PubDate: 2016-06-15T13:05:29.75861-05:0
      DOI: 10.1002/aic.15320
       
  • Discrete particle modeling of lateral jets into a packed bed and
           micromechanical analysis of the stability of raceways
    • Authors: Qinfu Hou; Dianyu E, Aibing Yu
      Pages: 4240 - 4250
      Abstract: Gas jets are often used to promote heat and mass transfer by forming raceways or circulating regions in a packed bed. Such an operation is common and critical in many processes. Multiple raceways can interact and be affected by the formation of different flow zones. This work develops a multiscale model to examine the formation and the stability of raceways and the underlying micromechanics. Four states are observed in the fluidized flow regime. More fundamentally, a critical bed width for the observation of different flow zones and states is found through numerical simulations and a theoretical analysis. Finally, the complicated transitions between different flow states are examined at a bed scale, and two general trends of the averaged solid velocity are found. The findings from the multiscale model are useful both scientifically for the understanding of state transitions and practically for the design and the operation of relevant chemical reactors. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4240–4250, 2016
      PubDate: 2016-06-21T10:55:38.366377-05:
      DOI: 10.1002/aic.15358
       
  • Design of parallel cyclones based on stability analysis
    • Authors: Chenxi Zhang; Qi Wang, Zhao Jia, Usman Muhammad, Weizhong Qian, Fei Wei
      Pages: 4251 - 4258
      Abstract: The uniform distribution of gas solids flow across parallel cyclones is required for high efficiency. In this study, we introduced mass flow rate ratio between solids and gas (CT) to present multi-phase interaction. And the direct Liapunov method is used to detect the instability of uniformity. Due to the special symmetry in this system, the criterion can be simplified into identifying the concavity (concave or convex) of pressure drop across a single cyclone with respect to CT. Then, based on the stability analysis of uniformity, a novel design principle is provided to prevent non-uniform distribution at dense phase. The effect of geometrical factor, i.e. dimensionless vortex finder diameter dr, on the stability of uniformity has been further investigated. The phase diagram, illustrating the effects of both operational parameter (CT) and geometrical parameter (dr) on stability of uniformity is calculated to give a clue of designing a robust parallel cyclones system. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4251–4258, 2016
      PubDate: 2016-06-24T14:45:35.15657-05:0
      DOI: 10.1002/aic.15366
       
  • Computational study of core-shell droplet formation in coaxial
           electrohydrodynamic atomization process
    • Authors: Wei-Cheng Yan; Pooya Davoodi, Yen Wah Tong, Chi-Hwa Wang
      Pages: 4259 - 4276
      Abstract: In this study, a computational fluid dynamic (CFD) model was developed to simulate the liquid cone-jet and core-shell droplet formation in the Coaxial Electrohydrodynamic Atomization (CEHDA) process. Validation experiments were conducted using poly(lactic acid) (PLA) and poly(lactic-co-glycolic acid) (PLGA) solutions as core and shell materials, respectively. Good agreement was obtained between experimental results and simulation predictions in terms of both particle size and core-shell structure. Investigation of interfacial tension between core and shell fluids showed that a stable compound cone-jet and droplet can be easily formed using miscible or partially miscible liquids compared with immiscible liquids with higher interfacial tension. It was also found that the nozzle tip configuration has significant effects on droplet production due to differences in fluid motion. The results also showed that the productivity of the CEHDA process, that is, slow production of core-shell microparticles due to low flow rates, could be enhanced using optimal cone-shaped nozzle configuration. Overall, this computational model provided a means of designing and optimizing CEHDA processes for large-scale core-shell microparticle fabrication in pharmaceutical application, such as selections of materials and nozzle configuration. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4259–4276, 2016
      PubDate: 2016-06-28T09:45:37.850067-05:
      DOI: 10.1002/aic.15361
       
  • Energy optimization of water supply system scheduling: Novel MINLP model
           and efficient global optimization algorithm
    • Authors: Hanyu Shi; Fengqi You
      Pages: 4277 - 4296
      Abstract: This article is concerned with global optimization of water supply system scheduling with pump operations to minimize total energy cost. The scheduling problem is first formulated as a non-convex mixed-integer nonlinear programming (MINLP) problem, accounting for flow rates in pipes, operation profiles of pumps, water levels of tanks, and customer demand. Binary variables denote on–off switch operations for pumps and flow directions in pipes, and nonlinear terms originate from characteristic functions for pumps and hydraulic functions for pipes. The proposed MINLP model is verified with EPANET, which is a leading software package for water distribution system modeling. We further develop a novel global optimization algorithm for solving the non-convex MINLP problem. To demonstrate the applicability of the proposed model and the efficiency of the tailored global optimization algorithm, we present results of two case studies with up to 4 tanks, 5 pumps, 5 check valves, and 21 pipes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4277–4296, 2016
      PubDate: 2016-06-08T10:25:43.827642-05:
      DOI: 10.1002/aic.15332
       
  • Optimization models for planning shale gas well refracture treatments
    • Authors: Diego C. Cafaro; Markus G. Drouven, Ignacio E. Grossmann
      Pages: 4297 - 4307
      Abstract: Refracturing is a promising option for addressing the characteristically steep decline curves of shale gas wells. In this work we propose two optimization models to address the refracturing planning problem. First, we present a continuous-time nonlinear programming model based on a novel forecast function that predicts pre- and post-treatment productivity declines. Next, we propose a discrete-time, multi-period mixed-integer linear programming (MILP) model that explicitly accounts for the possibility of multiple refracture treatments over the lifespan of a well. In an attempt to reduce solution times to a minimum, we compare three alternative formulations against each other (big-M formulation, disjunctive formulation using Standard and Compact Hull-Reformulations) and find that the disjunctive models yield the best computational performance. Finally, we apply the proposed MILP model to two case studies to demonstrate how refracturing can increase the expected recovery of a well and improve its profitability by several hundred thousand USD. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4297–4307, 2016
      PubDate: 2016-06-14T11:34:17.070783-05:
      DOI: 10.1002/aic.15330
       
  • Kriging meta-model assisted calibration of computational fluid dynamics
           models
    • Authors: Olumayowa T. Kajero; Rex B. Thorpe, Tao Chen, Bo Wang, Yuan Yao
      Pages: 4308 - 4320
      Abstract: Computational fluid dynamics (CFD) is a simulation technique widely used in chemical and process engineering applications. However, computation has become a bottleneck when calibration of CFD models with experimental data (also known as model parameter estimation) is needed. In this research, the kriging meta-modeling approach (also termed Gaussian process) was coupled with expected improvement (EI) to address this challenge. A new EI measure was developed for the sum of squared errors (SSE) which conforms to a generalized chi-square distribution and hence existing normal distribution-based EI measures are not applicable. The new EI measure is to suggest the CFD model parameter to simulate with, hence minimizing SSE and improving match between simulation and experiments. The usefulness of the developed method was demonstrated through a case study of a single-phase flow in both a straight-type and a convergent-divergent-type annular jet pump, where a single model parameter was calibrated with experimental data. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4308–4320, 2016
      PubDate: 2016-06-21T10:40:28.416904-05:
      DOI: 10.1002/aic.15352
       
  • Communication delays and data losses in distributed adaptive high-gain EKF
    • Authors: Mohammad Rashedi; Jinfeng Liu, Biao Huang
      Pages: 4321 - 4333
      Abstract: In this work, we consider distributed adaptive high-gain extended Kalman filtering for nonlinear systems subject to data losses and delays in communications. Specifically, we consider a class of nonlinear systems that consist of several subsystems interacting with each other via their states. A local adaptive high-gain extended Kalman filter is designed for each subsystem and the distributed estimators communicate to exchange the information. Each subsystem estimator takes the advantage of a predictor accounting for the delays and data losses simultaneously. The predictor of each subsystem is used to generate state predictions of interacting subsystems for interaction compensation. To get a reliable prediction, the predictors are designed based on a prediction-update algorithm. The convergence of the proposed distributed state estimation is ensured under sufficient conditions handling communication delays and data losses. Finally, a chemical process example is used to evaluate the applicability and effectiveness of the proposed design. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4321–4333, 2016
      PubDate: 2016-06-22T15:00:52.883786-05:
      DOI: 10.1002/aic.15351
       
  • Block adaptive kernel principal component analysis for nonlinear process
           monitoring
    • Authors: Lei Xie; Zhe Li, Jiusun Zeng, Uwe Kruger
      Pages: 4334 - 4345
      Abstract: On-line modeling of multivariate nonlinear system based on multivariate statistical methods has been studied extensively due to its industrial requirements. In order to further improve the modeling efficiency, a fast Block Adaptive Kernel Principal Component Analysis algorithm is proposed. Comparing with the existing work, the proposed algorithm (1) does not rely on iterative computation in the calculating process, (2) combines the up- and downdating operations to become a single one (3) and describes the adaptation of the Gram matrix as a series of rank-1 modification. In addition, (4) the updation of the eigenvalues and eigenvectors is of O(N) and high-precision. The computational complexity analysis and the numerical study show that the derived strategy possesses better ability to model the time-varying nonlinear variable interrelationships in process monitoring. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4334–4345, 2016
      PubDate: 2016-06-28T09:25:31.509105-05:
      DOI: 10.1002/aic.15347
       
  • Maldistribution susceptibility of monolith reactors: Case study of glucose
           hydrogenation performance
    • Authors: Markus Schubert; Sebastian Kost, Rüdiger Lange, Tapio Salmi, Stefan Haase, Uwe Hampel
      Pages: 4346 - 4364
      Abstract: In this work an ultrafast electron beam X-ray modality was applied for the first time to characterize the gas–liquid Taylor flow inside each channel of an opaque honeycomb monolith structure (65 cpsi) for uG,S=0.1 … 0.5 m/s anduL,S=0.2 m/s. Significant spatial and temporal deviations in the phase holdup as well as in the gas bubble and liquid slug lengths were found. To evaluate the impact of Taylor flow maldistribution on the reactor performance, the data of more than 125,000 unit cells were used to simulate the reactor productivity in the hydrogenation of glucose. The results verify that a monolith reactor solely designed by using superficial velocities and empirical correlations for gas bubble and liquid slug lengths fails significantly in achieving high product selectivity and the desired conversion. The developed methods are a solid base to design and select proper distributors ensuring the favorable flow configurations for specific chemical processes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4346–4364, 2016
      PubDate: 2016-06-09T11:01:45.666942-05:
      DOI: 10.1002/aic.15334
       
  • Effects of Ga doping on Pt/CeO2-Al2O3 catalysts for propane
           dehydrogenation
    • Authors: Tuo Wang; Feng Jiang, Gang Liu, Liang Zeng, Zhi-jian Zhao, Jinlong Gong
      Pages: 4365 - 4376
      Abstract: This paper describes catalytic consequencesThis paper describes catalytic consequences of Pt/CeO2-Al2O3 catalysts promoted with Ga species for propane dehydrogenation. A series of PtGa/CeO2-Al2O3 catalysts were prepared by a sequential impregnation method. The as-prepared catalysts were characterized employing N2 adsorption-desorption, X-ray diffrtaction, temperature programmed reduction, O2 volumetric chemisorption, H2-O2 titration, and transmission electron microscopy. We have shown that Ga3+ cations are incorporated into the cubic fluorite structure of CeO2, enhancing both lattice oxygen storage capacity and surface oxygen mobility. The enhanced reducibility of CeO2 is indicative of higher capability to eliminate the coke deposition and thus is beneficial to the improvement of catalytic stability. Density functional theory calculations confirm that the addition of Ga is prone to improve propylene desorption and greatly suppress deep dehydrogenation and the following coke formation. The catalytic performance shows a strong dependence on the content of Ga addition. The optimal loading content of Ga is 3 wt %, which results in the maximal propylene selectivity together with the best catalytic stability against coke accumulation. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4365–4376, 2016
      PubDate: 2016-06-09T11:05:30.416226-05:
      DOI: 10.1002/aic.15339
       
  • Increasing selectivity of the hydroformylation in a miniplant: Catalyst,
           solvent, and olefin recycle in two loops
    • Authors: J. M. Dreimann; H. Warmeling, J. N. Weimann, K. Künnemann, A. Behr, A. J. Vorholt
      Pages: 4377 - 4383
      Abstract: The application of thermomorphic solvent systems offers the combination of homogeneous catalysis in a single phase and catalyst recovery via phase separation. To increase economic feasibility the minimization of waste streams and side reactions is desired. For this, a continuous process for the hydroformylation of 1-dodecene in the solvent system DMF/n-decane is shown. While the Rh/Biphephos catalyst is recycled in DMF in a first loop, the n-decane and remaining olefins are separated from the product via distillation to form the second loop. In this process the need for additional solvent supply and the isomerization reaction of 1-dodecene is reduced significantly. The reaction toward internal olefins decreases from initially 15 to 3%. The stable hydroformylation process with a yield of the linear hydroformylation product of 55% and l/b-ratio of 95/5 is shown for 120 h. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4377–4383, 2016
      PubDate: 2016-06-09T10:40:49.166481-05:
      DOI: 10.1002/aic.15345
       
  • Cobalt molybdenum oxide catalysts for selective oxidation of cyclohexane
    • Authors: Ashish P. Unnarkat; Tam Sridhar, Huanting Wang, Sanjay Mahajani, Akkihebbal K. Suresh
      Pages: 4384 - 4402
      Abstract: Oxidation of cyclohexane has been carried out using molecular oxygen over cobalt molybdenum oxide (CoMoO4) catalysts in solvent free conditions. The catalysts were prepared using citrate method with three different molar ratios of Co:Mo, 1:1, 1:2, and 2:1 along with individual oxides for comparative studies. While all the catalysts showed significant activity and selectivity, CoMoO4 with 1:1 ratio showed the best performance compared to the others with a conversion of 7.38%, with selectivity to cyclohexanol and cyclohexanone (KA oil) of 94.3%, in 1 h. The performance of the catalyst, has been studied as a function of oxygen pressure, reaction temperature, and catalyst loading. It was observed that the catalyst deactivates during the course of the reaction. The reasons for deactivation and methods for restoring the activity have been studied. A kinetic model is presented that captures the complex kinetics and matches well with the experimental data. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4384–4402, 2016
      PubDate: 2016-06-17T14:45:33.52821-05:0
      DOI: 10.1002/aic.15335
       
  • Catalytic dehydration of glucose to 5-hydroxymethylfurfural with a
           bifunctional metal-organic framework
    • Authors: Ye Su; Ganggang Chang, Zhiguo Zhang, Huabin Xing, Baogen Su, Qiwei Yang, Qilong Ren, Yiwen Yang, Zongbi Bao
      Pages: 4403 - 4417
      Abstract: Glucose conversion to 5-hydroxymethylfurfural (HMF) generally undergoes catalytic isomerization reaction by Lewis acids followed by the catalytical dehydration to HMF with Brönsted acid. In this work, a sulfonic acid functionalized metal-organic framework MIL-101(Cr)-SO3H containing both Lewis acid and Brönsted acid sites, was examined as the catalyst for γ-valerolactone-mediated cascade reaction of glucose dehydration into HMF. Under the optimal reaction conditions, the batch heterogeneous reaction gave a HMF yield of 44.9% and selectivity of 45.8%. Reaction kinetics suggested that the glucose isomerization in GVL with 10 wt % water follows the second-order kinetics with an apparent activation energy of 100.9 kJ mol−1. Continuous reaction in the fixed-bed reactor showed that the catalyst is highly stable and able to provide a steady HMF yield. This work presents a sustainable and green process for catalytic dehydration of biomass-derived carbohydrate to HMF with a bifunctional metal-organic framework. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4403–4417, 2016
      PubDate: 2016-06-24T14:55:27.714648-05:
      DOI: 10.1002/aic.15356
       
  • The application of dynamic modeling for thermal risks analysis of the
           acid-catalyzed hydrolysis of glycidol
    • Authors: Juan Carlos Ojeda Toro; Izabela Dobrosz-Gómez, Miguel Ángel Gómez García
      Pages: 4418 - 4426
      Abstract: The aim of this work was to determine the limits of safe operation of continuous flow stirred-tank reactor (CSTR) for the acid-catalyzed hydrolysis of glycidol. The stability analysis was performed by dynamic modelling. The obtained results were compared with the experimental data reported in the open literature. For this purpose, dimensionless variables and parameters were introduced and unstable material and energy balances were defined. The system equations were solved using Matcont (Matlab® software). Thus, bifurcation diagrams (in one and two dimensions) were mapped. All different dynamic states were identified and studied (thermal stability and instability, with unique and multiple solutions; Hopf bifurcations; turning points and envelope of periodic solutions). Finally, the intrinsic thermal unstable and cycle behavior of the acid-catalyzed hydration of glycidol to produce glycerol was identified. The appropriate conditions to guarantee safe operation of CSTR were found. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4418–4426, 2016
      PubDate: 2016-06-27T09:25:27.085986-05:
      DOI: 10.1002/aic.15353
       
  • Wetting forces and meniscus pinning at geometrical edges
    • Authors: Willem-Jan A. de Wijs; Jozua Laven, Gijsbertus de With
      Pages: 4453 - 4465
      Abstract: It is shown that complications in currently used optical measurements for wetting and flow resistance over edges can be circumvented by surface tension force measurements. These forces are measured by employing a modified Wilhelmy plate testing technique in which a plate with rectangular holes is immersed. The forces measured during immersion and emersion are subdivided into mass, buoyancy, and surface tension related parts, where the flow resistance when the meniscus passes horizontal faces and edges of the plate receives particular attention. Combining this experimental method with wetting theory, we show that we can predict and measure the full force curve for meniscus shape transitions over edge geometries under quasi-static conditions. Moreover, wetting effects directly linked to surface defects can be detected qualitatively. We also point to the speed-dependent rupture of metastable films formed during emersion. The measurement method designed is most relevant in cases where optical methods cannot be used. © 2016 The
      Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 62: 4453–4465, 2016
      PubDate: 2016-06-09T10:45:36.10473-05:0
      DOI: 10.1002/aic.15341
       
  • Mass-transfer enhancement in single drop extraction in the presence of
           magnetic nanoparticles and magnetic field
    • Authors: Amid Vahedi; Asghar Molaei Dehkordi, Farzad Fadaei
      Pages: 4466 - 4479
      Abstract: Magnetite nanoparticles with an average particle size of 28.8 nm were synthesized, coated with oleic acid, and characterized using various techniques such as DLS, FT-IR, SEM, XRD, VSM, and UV-Vis analysis. A nanofluid consisting of synthesized nanoparticles and 5 wt % acetic acid in toluene as the dispersed phase was prepared and used in the chemical test system, Toluene-Acetic Acid-Water, for the single drop extraction in the presence and absence of an external oscillating magnetic field. Influences of various operating and design parameters such as nanoparticle concentration, drop diameter, and the applied current and frequency on the overall mass-transfer coefficients for the mass-transfer direction from dc were investigated carefully. The obtained results were used to propose a general correlation for the mass-transfer enhancement. It was found that the maximum mass-transfer enhancement compared with that obtained in the absence of nanoparticles and the oscillating magnetic field is about 259%. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4466–4479, 2016
      PubDate: 2016-06-21T10:45:50.143009-05:
      DOI: 10.1002/aic.15357
       
  • Hydrophobic protic ionic liquids tethered with tertiary amine group for
           highly efficient and selective absorption of H2S from CO2
    • Authors: Kuan Huang; Xiao-Min Zhang, Xing-Bang Hu, You-Ting Wu
      Pages: 4480 - 4490
      Abstract: Developing absorbents with both high absorption capacity of H2S and large selectivity of H2S/CO2 is very important for natural gas sweetening process. To this end, a class of novel hydrophobic protic ionic liquids (ILs) containing free tertiary amine group as functional site for the absorption of H2S were designed in this work. They were facilely synthesized through a simple neutralization-metathesis methodology by utilizing diamine compounds and bis(trifluoromethylsulfonyl)imide as the building blocks for cation and anion, respectively. Impressively, the solubility of H2S can reach 0.546 mol mol−1 (1 bar) and 0.225 mol mol−1 (0.1 bar), and the selectivity of H2S/CO2 can reach 37.2 (H2S solubility at 1 bar vs. CO2 solubility at 1 bar) and 15.4 (H2S solubility at 0.1 bar vs. CO2 solubility at 1 bar) in the hydrophobic protic ILs at 298.2 K. Comparing the hydrophobic protic ILs with other absorbents justifies their superior performance in the selective absorption of H2S from CO2. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4480–4490, 2016
      PubDate: 2016-06-21T10:20:34.100376-05:
      DOI: 10.1002/aic.15363
       
  • Metal-organic frameworks for highly efficient adsorption of
           dibenzothiophene from liquid fuels
    • Authors: Weijia Tang; Jianlei Gu, Hongliang Huang, Dahuan Liu, Chongli Zhong
      Pages: 4491 - 4496
      Abstract: By taking desulfurization of liquid fuels as a demonstrative example, a bottom-up selection was performed to find the metal-organic frameworks (MOF)-type adsorbents with highly efficient adsorption performance of large molecules. Through carefully analyzing the adsorption mechanism for typical S-heterocyclic compounds like dibenzothiophene (DBT), PCN-10 was selected in consideration of the simultaneous inclusion of several kinds of interactions in the framework. Experimental results demonstrate that this MOF exhibits extraordinary high DBT adsorption capacity (75.24 mg S g−1), showing record uptake among all the reported porous materials for the removal of thiophenicsulfur from fuels (below 1000 ppmwS), to the best of our knowledge. Moreover, the removal rate for the low sulfur concentration (50 ppmwS) can reach beyond 99%. This strategy can be conveniently extended to the screening and design of MOFs for the efficient removal of other important large guest molecules. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4491–4496, 2016
      PubDate: 2016-06-30T10:30:25.871685-05:
      DOI: 10.1002/aic.15384
       
  • Reliable mixture critical point computation using polynomial homotopy
           continuation
    • Authors: Hythem Sidky; Jonathan K. Whitmer, Dhagash Mehta
      Pages: 4497 - 4507
      Abstract: The numerical computation of multicomponent mixture critical points has been the subject of much study due to their theoretical and practical importance. Both deterministic and stochastic methods have been applied with varying degrees of reliability and robustness. In this work, we utilize numerical polynomial homotopy continuation (NPHC) to reliably identify all mixture critical points. This method is unique due to its robustness, initialization-free nature and ease of parallelization. For a given system of equations, all complex solutions are found. Computational times are also found to be invariant to mixture composition. We validate this technique against previous work and extend the method to mixtures of up to eight components. NPHC is shown to be a modern and powerful technique which offers mathematical reliability at a moderate computational cost. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4497–4507, 2016
      PubDate: 2016-06-03T09:31:51.79473-05:0
      DOI: 10.1002/aic.15319
       
  • Theoretical model for multiple breakup of fluid particles in turbulent
           flow field
    • Authors: Kiyanoosh Razzaghi; Farhad Shahraki
      Pages: 4508 - 4525
      Abstract: Generalized phenomenological model, based on the theories of probability and isotropic turbulence, is developed for multiple breakup of fluid particles in turbulent flow field. The approach uses a series of successive binary breakup events occur at a time scale comparable to the colliding eddy turnover time. It was found that the use of energy density, instead of energy, will increase the predicted binary breakup rate which is usually underestimated by the existing models in the literature. Generalization of the binary breakup model for multiple fragmentations is performed by defining a “remaining energy function” for the colliding eddy which means the contribution of original eddy to the later breakup events. For ternary breakage, the model shows a reasonably good agreement with the experimental data. The quaternary fragmentation frequency, however, is of negligible importance at lower energy dissipation rates but its contribution to breakage fraction at higher energy dissipation rates becomes considerable. The results also show that ternary and quaternary breakups have a considerable 90% contribution to the overall fragmentation, while pentenary and further fragmentations are of lower importance at low energy dissipation rates. At higher levels of energy dissipation rate, fragmentations up to six daughter particles contribute to more than 95% of the overall fragmentations. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4508–4525, 2016
      PubDate: 2016-05-29T17:50:38.850049-05:
      DOI: 10.1002/aic.15314
       
  • Development of soft-sphere contact models for thermal heat conduction in
           granular flows
    • Authors: A. B. Morris; S. Pannala, Z. Ma, C. M. Hrenya
      Pages: 4526 - 4535
      Abstract: Conductive heat transfer to flowing particles occurs when two particles (or a particle and wall) come into contact. The direct conduction between the two bodies depends on the collision dynamics, namely the size of the contact area and the duration of contact. For soft-sphere discrete-particle simulations, it is computationally expensive to resolve the true collision time because doing so would require a restrictively small numerical time step. To improve the computational speed, it is common to increase the “softness” of the material to artificially increase the collision time, but doing so affects the heat transfer. In this work, two physically-based correction terms are derived to compensate for the increased contact area and time stemming from artificial particle softening. By including both correction terms, the impact that artificial softening has on the conductive heat transfer is removed, thus enabling simulations at greatly reduced computational times without sacrificing physical accuracy. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4526–4535, 2016
      PubDate: 2016-06-08T10:15:29.273557-05:
      DOI: 10.1002/aic.15331
       
  • The effect of shear-thickening on the stability of slot-die coating
    • Authors: Sunilkumar Khandavalli; Jonathan P. Rothstein
      Pages: 4536 - 4547
      Abstract: Slot-die coating is an economical roll-to-roll processing technique with potential to revolutionize the fabrication of nano-patterned thin films at high throughput. In this study, the impact of shear-thickening of the coating fluid on the stability of slot-die coating was investigated. For the coating fluid, a model system fumed silica nanoparticles dispersed in polypropylene glycol was chosen. These dispersions exhibit shear and extensional thickening characterized through steady shear and capillary break-up measurements. The critical web velocity for the onset of coating defect for different flow rates was measured, while the type of coating defect was visualized using a high speed camera. For the shear thickening particle dispersions, the coating failed through the onset of a ribbing instability. The critical web velocity for the onset of coating defect was found to decrease with increasing particle concentration and increasing fluid viscosity. The minimum wet thickness was studied as a function of capillary number for the particle dispersions and compared with a series of Newtonian fluids with similar viscosities. In all cases, shear-thickening behavior was found to stabilize coating by reducing the minimum wet coating thickness when compared against a Newtonian fluid with similar viscosity at the same capillary number. Conversely, the shear-thinning fluids tested destabilized the coating by increasing the minimum wet thickness when compared against a Newtonian at the same capillary number. The impact of shear-thickening on slot-die coating was further studied by quantifying the evolution of the ribbing instability with increasing web speed and by conducting tests over a wide range of coating gaps. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4536–4547, 2016
      PubDate: 2016-06-09T10:41:13.656602-05:
      DOI: 10.1002/aic.15336
       
  • Inducing arbitrary vapor pressures, and quantifying leakages
    • Authors: Rafael Tadmor; Priyanka S. Wasnik, Hartmann E. N'guessan, Rafael Tadmor, Maria Tadmor
      Pages: 4548 - 4553
      Abstract: We generalize the Maxwell drop evaporation equation to cover the range from closed system to open system through semiclosed system where the evaporation is restricted to an arbitrary degree which we show how to characterize. We first consider a suspended drop, and then a drop contacting a surface where the surface's vicinity restricts the evaporation paths. We show how to use these results to obtain arbitrary values of vapor pressure by simple manipulations of the numbers and sizes of droplets added to the system for a constant leak size, or, alternatively, control the leak size with a valve for given sizes of drops. We further show how to use this result to quantify a leakage in a system. Such a leakage is characterized using a single parameter (leakage length) which the described method calibrates. The calibrated leakage length can be used for systematic control of vapor concentrations within the chamber. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4548–4553, 2016
      PubDate: 2016-06-13T13:35:29.102356-05:
      DOI: 10.1002/aic.15329
       
  • Nonrecirculating flow of a yield stress fluid around a circular cylinder
           in a poiseuille flow
    • Authors: Hamdullah Ozogul; Pascal Jay, Albert Magnin
      Pages: 4554 - 4563
      Abstract: Although yield stress fluids are very present today in everyday life and in industry, their flow behavior is still poorly understood and the databases are incomplete at this time. The present experimental and numerical study focuses on laminar nonrecirculating flows of an elastoviscoplastic model fluid in a rectangular duct. An original experimental set-up has been developed. The Particle Image Velocimetry method is used for analyzing the kinematical fields. Results provided concern the morphology of the flow and the evolution of the velocity field around a cylindrical obstacle. Information is provided on the size of the rigid zones where the fluid behaves as a solid. The experimental data are compared with numerical results involving a regularized Herschel–Bulkley viscoplastic model. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4554–4563, 2016
      PubDate: 2016-06-21T10:35:37.733832-05:
      DOI: 10.1002/aic.15350
       
  • Droplet formation of H2SO4/alkane system in a T-junction microchannel:
           Gravity effect
    • Authors: Liantang Li; Jisong Zhang, Kai Wang, Jianhong Xu, Guangsheng Luo
      Pages: 4564 - 4573
      Abstract: A special system of concentrated sulfuric acid (H2SO4) and n-hexane was used to study the droplet formation in a glass T-junction microchannel with H2SO4 as the continuous phase. The effects of capillary number, flow ratio, and viscosity ratio on the droplet formation were investigated. The effect of gravity was explored by changing the flow direction in the microchannel. Results showed that the formation of transition flow pattern from squeezing to dripping is much easier for this special system compared with common aqueous/organic systems. This phenomenon is due to the considerably higher viscosity of H2SO4 than that of common aqueous phase and the higher density difference of the system compared with those of common systems. In addition to capillary number and flow ratio, gravity evidently affects the formation of droplets and flow patterns. The droplet size is smaller than that during the horizontal flow when the flow direction is consistent with gravity. By contrast, flow direction contrary to that of gravity results in larger droplet size than that at horizontal flow. This phenomenon provides guidance on the operation of these special systems in microchannels. Finally, mathematical models of droplet size at different flow patterns have been established, and these models can predict droplet size very well. This study could be helpful to extend the application of microreactors to new working systems. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4564–4573, 2016
      PubDate: 2016-06-21T10:55:48.793146-05:
      DOI: 10.1002/aic.15354
       
  • Tensorial navier-slip boundary conditions for patterned surfaces for fluid
           mixing: Numerical simulations and experiments
    • Authors: Hye Kyeong Jang; Young Ju Kim, Nam Sub Woo, Wook Ryol Hwang
      Pages: 4574 - 4585
      Abstract: Navier-slip boundary condition has been investigated for patterned surfaces with various grooves for the application to fluid mixing by controlling flow patterns. Simple tensorial expression is applied for anisotropically patterned surfaces and effective slip lengths for various grooves have been evaluated for a wide range of Reynolds numbers and aspect ratios using a flow rate matching technique. By doing so, the applicability of the effective tensorial slip model has been presented that replaces physical surface patterns to reduce computational cost significantly. Using a simple model agitator with a rotating disk, modification of flow characteristics with various alignment angles of the patterned surface has been investigated. We report a critical Reynolds number of O(1) for flows in agitators, below which effective slip dominates over fluid inertia. Patterned poly(dimethylsiloxane) sheets are fabricated using a compression-molding/soft-lithography technique and flow visualization with laser-induced fluorescence reveals controllability of flow patterns with the patterned surface. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4574–4585, 2016
      PubDate: 2016-06-21T10:50:38.064965-05:
      DOI: 10.1002/aic.15355
       
 
 
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