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  Subjects -> ENGINEERING (Total: 2269 journals)
    - CHEMICAL ENGINEERING (190 journals)
    - CIVIL ENGINEERING (181 journals)
    - ELECTRICAL ENGINEERING (101 journals)
    - ENGINEERING (1203 journals)
    - ENGINEERING MECHANICS AND MATERIALS (389 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (61 journals)
    - MECHANICAL ENGINEERING (89 journals)

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

Showing 201 - 400 of 1205 Journals sorted alphabetically
Current Science     Open Access   (Followers: 46)
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   (Followers: 1)
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   (Followers: 1)
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: 5)
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: 39)
Emitter : International Journal of Engineering Technology     Open Access  
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: 10)
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: 5)
Engineering Economist, The     Hybrid Journal   (Followers: 6)
Engineering Failure Analysis     Hybrid Journal   (Followers: 64)
Engineering Geology     Hybrid Journal   (Followers: 10)
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: 5)
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: 7)
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: 119)
Geotechnical Testing Journal     Full-text available via subscription   (Followers: 9)
Géotechnique     Hybrid Journal   (Followers: 14)
Geothermics     Hybrid Journal   (Followers: 6)
Glass Technology - European Journal of Glass Science and Technology Part A     Full-text available via subscription   (Followers: 4)
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: 7)
IBM Journal of Research and Development     Hybrid Journal   (Followers: 17)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 49)
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: 68)
IEEE Engineering Management Review     Full-text available via subscription   (Followers: 35)
IEEE Geoscience and Remote Sensing Letters     Hybrid Journal   (Followers: 109)
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: 16)
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: 29)
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: 32)
IEEE Potentials     Full-text available via subscription   (Followers: 19)
IEEE Signal Processing Letters     Hybrid Journal   (Followers: 37)
IEEE Spectrum     Full-text available via subscription   (Followers: 137)
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: 38)
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: 8)
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: 20)
IEEE Transactions on Instrumentation and Measurement     Hybrid Journal   (Followers: 50)
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: 33)
IEEE Transactions on Semiconductor Manufacturing     Hybrid Journal   (Followers: 6)
IEEE Transactions on Signal Processing     Hybrid Journal   (Followers: 63)
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)

  First | 1 2 3 4 5 6 7 | Last

Journal Cover AIChE Journal
  [SJR: 1.122]   [H-I: 120]   [28 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  [1605 journals]
  • Arbitrary shaped ice particle melting under the influence of natural
           convection
    • Authors: Hemant Bansal; Petr Nikrityuk
      Abstract: This work is devoted to numerical simulations of an arbitrary shaped ice particle melting inside water under the influence of natural convection. Specifically, four different shapes of the ice particle have been studied: sphere, cylinder, cross shaped cylinder and irregular sphere with radial bumps on its surface. A 2D axisymmetric particle-resolved numerical model has been employed on a fixed grid to study the detailed melting dynamics of an ice particle. The solid-liquid interface is treated as a porous medium characterized by the permeability coefficient which is used to damp the velocity values inside the interface. The model results have been compared with an existing experimental results produced by A. Shukla et al. (Metal. Mater. Trans. B, 42(1):224–235, 2011). Very good agreement between our predictions and experimental data have been achieved. Based on the analysis of numerical simulation results, melting process is found to advance through two distinct regimes, namely, establishment of the natural convection and active melting of ice particle exhibiting substantial amount of fluidparticle interactions. A set of dimensionless parameters have been identified to distinguish between regimes. Finally, we developed a semi-empirical to predict the melting of any arbitrary shaped ice particle and validated it against the particle-resolved numerical simulation and experimental results. The comparison showed good agreement. Finally, the presented semiempirical model can be used as sub-grid model in Euler-Lagrange based numerical models to study the phase change phenomena in particulate flow systems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-11T18:10:32.881842-05:
      DOI: 10.1002/aic.15643
       
  • Robust Batch-to-Batch Optimization in the Presence of Model-Plant Mismatch
           and Input Uncertainty
    • Authors: Rubin Hille; Jasdeep Mandur, Hector M. Budman
      Abstract: In model-based optimization in the presence of model-plant mismatch, the set of model parameter estimates which satisfy an identification objective may not result in an accurate prediction of the gradients of the cost-function and constraints. To ensure convergence to the optimum, the predicted gradients can be forced to match the measured gradients by adapting the model parameters. Since updating all available parameters is impractical due to estimability problems and overfitting, there is a motivation for adapting a subset of parameters for updating the predicted outputs and gradients. This paper presents an approach to select a subset of parameters based on the sensitivities of the model outputs and of the cost function and constraint gradients. Furthermore, robustness to uncertainties in initial batch conditions is introduced using a robust formulation based on polynomial chaos expansions. The improvements in convergence to the process optimum and robustness are illustrated using a fed-batch bioprocess. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-11T18:10:29.727885-05:
      DOI: 10.1002/aic.15645
       
  • Investigation of CO2 Removal by Immobilized Carbonic Anhydrase Enzyme in a
           Hollow-Fiber Membrane Bioreactor
    • Authors: Ion Iliuta; Maria C. Iliuta
      Abstract: Gas-liquid membrane contactors are compelling candidate bioreactors for implementing CO2 capture because of large mass transfer rates and liquid-solid interfaces, low pressure drop, low axial dispersion and mixing, modularity, simple scale-up or scale-down and operational suppleness. Binding the carbonic anhydrase (CA) enzyme on the membrane surface adds extra advantages due to the impressive large hydration turnover number and offers an attractive way for CO2 capture. This novel approach to CO2 removal by immobilized CA in a hollow-fiber membrane bioreactor (HFMB) was investigated via a multiscale steady-state model, under gas-filled and partially liquid-filled membrane pores conditions. The impact of CA loading, buffer acid-base constant and concentration, membrane wetting, uncatalyzed/catalyzed CO2 hydration in the wetted membrane zone, operating conditions and cocurrent/countercurrent flow orientation on the HFMB performance was analyzed. The results showed that this low-cost, green, and environmentally friendly technology could be an appealing alternative to CO2 capture from stationary emissions sources. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-11T18:05:32.260496-05:
      DOI: 10.1002/aic.15646
       
  • A Game Theoretic Framework for Petroleum Refinery Strategic Production
           Planning
    • Authors: Philip Tominac; Vladimir Mahalec
      Abstract: A game theoretic framework for strategic refinery production planning is presented in which strategic planning problems are formulated as non-cooperative potential games whose solutions represent Nash equilibria. The potential game model takes the form of a nonconvex nonlinear program (NLP) and we examine an additional scenario extending this to a nonconvex mixed integer nonlinear program (MINLP). Tactical planning decisions are linked to strategic decision processes through a potential game structure derived from a Cournot oligopoly-type game in which multiple crude oil refineries supply several markets. Two scenarios are presented which illustrate the utility of the game theoretic framework in the analysis of production planning problems in competitive scenarios. Solutions to these problems are interpreted as mutual best responses yielding maximum profit in the competitive planning game. The resulting production planning decisions are rational in a game theoretic sense and are robust to deviations in competitor strategies. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-11T18:05:27.285315-05:
      DOI: 10.1002/aic.15644
       
  • Flow chemistry – Microreaction technology comes of age
    • Authors: Klavs F. Jensen
      PubDate: 2017-01-11T18:05:24.737609-05:
      DOI: 10.1002/aic.15642
       
  • A Geometric Framework for Monitoring and Fault Detection for Periodic
           Processes
    • Authors: Ray Wang; Thomas F. Edgar, Michael Baldea
      Abstract: This paper focuses on data-driven monitoring and fault detection for processes subject to periodic operation. Although cyclical operation systems are relatively widespread in practice (notably in the realm of physical separations, e.g., pressure-swing adsorption and chromatography), the development of specific fault detection mechanisms has received little attention compared to the extensive efforts dedicated to continuous or batch processes. Here, we propose a novel geometric approach for process fault detection. Specifically, we develop a time-explicit multivariable representation of data collected from the process, which provides a natural framework for defining “normal” operation and the corresponding confidence regions. On this basis, we proceed with a two-step fault detection approach, based on detecting inter-cycle variations to locate a faulty cycle, and intra-cycle changes to determine the exact timing of a fault. We illustrate the theoretical developments with two simulation case studies. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-10T17:50:34.813509-05:
      DOI: 10.1002/aic.15638
       
  • Erratum: Why Not Try Active Learning
    • Authors: Cecilia Banzon
      Abstract: John L. Falconer. Why Not Try Active Learning? AIChE J. 2016;62:4174–4181.In this recently published article, John L. Falconer, the winner of the “2015 Warren K. Lewis Award for Chemical Engineering Education,” was inadvertently omitted. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-10T17:50:22.631981-05:
      DOI: 10.1002/aic.15639
       
  • Regulating the Micromixing Efficiency of a Novel Helical Tube Reactor by
           Premixing Behavior Optimization
    • Authors: Jiang-Zhou Luo; Guang-Wen Chu, Yong Luo, Moses Arowo, Bao-Chang Sun, Jian-Feng Chen
      Abstract: In this work, a novel helical tube reactor (HTR) was constructed, including a pre-mixer for adjusting the premixing behavior of reactants and a helical tube as a further mixing unit. The pre-mixer was modified to optimize the premixing behavior by using two methods, named as tangential-feeding and insertion of a helical baffle. The premixing behaviors were investigated via computational fluid dynamics (CFD) simulation. Simulation results indicated that both methods can change the fluid flow, enhance the turbulence kinetic energy, and improve the premixing performance in the pre-mixers. Based on the results of CFD simulation, it could be predicted that the micromixing efficiency of the HTR can be regulated by these methods accordingly. Then the predicated results were confirmed experimentally by a parallel competing reaction. Furthermore, the relationship between the premixing performance increasing and the corresponding micromixing efficiency increasing of the HTR was quantitatively analyzed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-10T17:11:46.535397-05:
      DOI: 10.1002/aic.15641
       
  • The influence of injection velocity and relaxation time on the spreading
           of tracers in viscoelastic liquids agitated by submerged, recirculating
           jets with low reynolds numbers
    • Authors: P.K. Bhattacharjee; S.P. Kennedy, Q. Xu, Nicky Eshtiaghi, R. Parthasarathy
      Abstract: We provide experimental demonstration that the spread of tracer elements in a tank containing a viscoelastic liquid and agitated by a submerged jet pointing to the base of the tank can be influenced by the relaxation time of the liquid. We analyzed the temporal spreading of the boundary of a tracer-front in two dimensions using flow visualisation at early stages and found that for a given fluid, the evolution of the tracer-front at various injection velocities follows a universal trajectory when considered on a normalised time scale of t/νN2/κ, where t is observation time, νN is injection velocity and κ is the effective diffusivity of the tracer elements in the medium. For a different fluid, at a given vN, the trajectory scales with the relaxation time of the fluid. The importance of relaxation time to the evolution of a tracer-front is something previously unreported. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-10T17:05:39.981894-05:
      DOI: 10.1002/aic.15640
       
  • Molecular Mechanism for Liquid–liquid Extraction: Two-film Theory
           Revisited
    • Authors: Yangxu Hu; Zhiping Liu, Xigang Yuan, Xianren Zhang
      Abstract: We investigate here the molecular mechanism for liquid–liquid extraction and revisit the classical two-film theory. With equilibrium and non-equilibrium molecular dynamics simulations, we illustrate the kinetics of solute crossing the interface and in particular the structure of the interface at which two stagnant liquid films adhere. Our simulation results show that beyond the two-film theory, the interface is well structured and plays an essential role in solute transfer. We found that at the well-developed interface region the overall density profile exhibits a dip, while the solute concentration shows a significant maximum. Free energy analysis demonstrates the interfacial enrichment of solute molecules serving as a potential well for solute adsorption. Thus, different from the assumption of the two-film theory, our simulations show that there exists a resistance for solute molecules crossing the interface, which could be overcome only at high interface concentration of solute caused by interfacial enrichment. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-05T04:05:32.940094-05:
      DOI: 10.1002/aic.15636
       
  • Design and Construction of an Equipment for the Determination of
           Solubility of Gases in Liquids
    • Authors: Luis C.A. Garzon; Carmen M. Romero, Andres F. Suarez
      Abstract: This paper presents the design and construction of a new isochoric saturation apparatus for the determination of gas solubility in liquids based on the gas drop pressure method. The major improvement of this design is the separation between the solubility and the gas cells. With this separation, the change of pressure and temperature inside the system is minimum when the gas gets in contact with the liquid and it allows degassing the liquid in an easy way. The performance of the equipment was evaluated measuring the solubility of argon and nitrogen in pure water at (283.15, 288.15, 293.15 y 298.15) K. The gas solubility was calculated according to the Henry's law. The results obtained and the comparison with literature values show that the equipment provides an accurate and precise method for determination of gas solubility in water. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-05T04:00:35.331266-05:
      DOI: 10.1002/aic.15637
       
  • High performance of La-promoted Fe2O3/α-Al2O3 oxygen carrier for
           chemical looping combustion
    • Authors: Ming Tian; Chaojie Wang, Lin Li, Xiaodong Wang
      Abstract: Iron oxide supported oxygen carrier (OC) is regarded to a promising candidate for chemical looping combustion (CLC). However, phase separation between Fe2O3 and supports often occurs resulted from the severe sintering of supports during calcination, which leads to the sintering and breakage of Fe2O3 thus the decrease of redox reactivity. In this paper, La-promoted Fe2O3/α-Al2O3 were used as OCs for CLC of CH4 and for the first time found that the OC with the addition of 18 wt% La exhibited outstanding reactivity and redox stability during 50 cycles of CLC of CH4. Such a superior performance originated from the formation of LaAl12O19 hexaaluminate (La-HA) phase with not only small particle size but also excellent thermal stability at CLC conditions, which worked as a binder to prevent the phase separation thereby the sintering and breakage of active species α-Fe2O3 were avoided during reaction. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-05T03:55:27.78545-05:0
      DOI: 10.1002/aic.15634
       
  • Effect of the Presence of Organic Matter on Bubble Points of Oils in
           Shales
    • Authors: Manas Pathak; Palash Panja, Raymond Levey, Milind Deo
      Abstract: The relative amounts of oil and gas produced in prolific plays like Eagle Ford are affected by the oil bubble point. The oil and kerogen (organic matter) are found in the same rock and the oil may remain in contact with the kerogen. Bulk experiments and molecular simulations clearly show that kerogen preferentially absorbs hydrocarbons. The absorbed oil phase remains in multi-component equilibrium with the expelled oil produced at the surface. Results from a model proposed to calculate the bubble points (at 400 K) of in-situ oils (absorbed + free) in the presence of kerogen indicate suppression of about 4150 kPa – 16350 kPa from the original value of 28025 kPa of produced Eagle Ford oil. These calculations depend on the type and level of maturity of kerogen. The prediction of accurate saturation pressures has key implications on volumes of recovery and rates of production from liquid rich shales. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-05T03:50:23.549307-05:
      DOI: 10.1002/aic.15635
       
  • Issue information
    • Abstract: Cover illustration. Incorporation of physical and biological phenomena in modeling mammalian cell bioreactors. Image courtesy: Parham Farzan. 10.1002/aic.15442
      PubDate: 2017-01-04T20:20:00.562089-05:
      DOI: 10.1002/aic.15465
       
  • Removal of NO from Flue Gas Using UV/S2O82- Process in A Novel
           Photochemical Impinging Stream Reactor
    • Authors: Yangxian Liu; Jun Zhang
      Abstract: A novel photochemical impinging stream reactor was developed for the first time. Removal process of NO from flue gas using sulfate radical (SO4-·) and hydroxyl radical (·OH) from UV-light activation of persulfate (UV/S2O82 advanced oxidation process) was investigated in the novel reactor. Experiments were conducted to evaluate the effects of S2O82- concentration, solution pH, UV power, solution temperature, liquid-gas ratio, flue gas flow, NO, SO2 and O2 concentrations on removal of NO. Mechanism and kinetics of NO removal were also studied. The results show that increasing UV power, solution temperature, S2O82- concentration or solution circulation rate promotes NO removal. Increasing solution pH (1.2 to 11.9), NO concentration or flue gas flow weakens NO removal. O2 concentration has no significant effect on NO removal. SO4-· and ·OH were the major active species for NO removal. Absorption rate equation and kinetic parameters of NO removal were obtained. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-03T18:05:27.998493-05:
      DOI: 10.1002/aic.15633
       
  • Synthesis and optimization of membrane cascade for gas separation via
           mixed-integer nonlinear programming (MINLP)
    • Authors: Alicia Aliaga-Vicente; José A. Caballero, María J. Fernández-Torres
      Abstract: Currently, membrane gas separation systems enjoy widespread acceptance in industry As multistage systems are needed to achieve high recovery and high product purity simultaneously, many such configurations are possible. These designs rely on the process engineer's experience and therefore sub-optimal configurations are often the result. This paper proposes a systematic methodology for obtaining the optimal multistage membrane flowsheet and corresponding operating conditions. The new approach is applied to cross-flow membrane modules that separate CO2 from CH4, for which the optimization of the proposed superstructure has been achieved via a MINLP model, with the gas processing cost as objective function. The novelty of this work resides in the large number of possible interconnections between each membrane module, the energy recovery from the high pressure outlet stream and allowing for non-isothermal conditions. The results presented in this work comprise the optimal flowsheet and operating conditions of two case studies. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-03T18:05:25.108554-05:
      DOI: 10.1002/aic.15631
       
  • Non-ionic soft materials influence on filtration resistance and cake dry
           matter content
    • Authors: Mogens Hinge; Morten Lykkegaard Christensen
      Abstract: Filtration of organic slurries is important in many industries but challenging because the hydraulic resistance is high due to gel materials in the slurries. Particles with solid polystyrene (PS) core and varying amount of poly(N-isopropylacrylamide) (PNIPAM) gel surface were synthesized. At low amount of gel, the gel deformed and partly filled the cake void increasing the resistance. This was successfully fitted using a semi-theoretical model for deformable particles. At high amount of gel, the gel deformed filling the entire cake void and the resistance was dominated by the gel. During consolidation, the primary retardation time increased three orders of magnitude with gel thickness as expected as primary consolidation were dominated by the dissipation of pore water. The secondary retardation time also increased but not as pronounced as primary retardation time. Secondary consolidation was due to local compression of the gel and therefore less dependent on gel thickness. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-03T18:05:23.361243-05:
      DOI: 10.1002/aic.15632
       
  • Issue information - table of contents
    • Pages: 397 - 397
      PubDate: 2017-01-04T20:20:06.12971-05:0
      DOI: 10.1002/aic.15464
       
  • Intensified and safe ozonolysis of fatty acid methyl esters in liquid CO2
           in a continuous reactor
    • Authors: Michael D. Lundin; Andrew M. Danby, Geoffrey R. Akien, Padmesh Venkitasubramanian, Kevin J. Martin, Daryle H. Busch, Bala Subramaniam
      Abstract: We demonstrate a continuous reactor for performing the ozonolysis of fatty acid methyl esters (FAMEs) using liquid CO2 as solvent. The fast reaction kinetics allows the use of small-volume reactors to completely convert the FAMEs, forming secondary ozonides as the primary products. The short residence times also help maximize the yields of the secondary ozonides by minimizing over-oxidation and the formation of oligomeric products. The liquid CO2 medium promotes safe reactor operation by providing an essential fraction of overall reactor cooling and by diluting the vapor phase organics. We also demonstrate a continuous stirred reactor for the safe thermal decomposition of the secondary ozonides to their corresponding acids and aldehydes. Using a lumped kinetic model for the thermal decomposition of the ozonolysis products, we estimate activation energy values of 108.6±0.6 kJ mol−1 for the decomposition of secondary ozonides and 122±3 kJ mol−1 for the decomposition of the undesired oligomeric species. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-30T03:15:30.931109-05:
      DOI: 10.1002/aic.15630
       
  • Hydrogenation of methyl acetate to ethanol by Cu/ZnO catalyst encapsulated
           in SBA-15
    • Authors: Yue Wang; Junyu Liao, Jian Zhang, Shengping Wang, Yujun Zhao, Xinbin Ma
      Abstract: The hydrogenation of methyl acetate (MA) is one of the important key processes for synthesis of ethanol from syngas. This work reports a highly efficient Cu-ZnO/SBA-15 catalyst prepared by facile solid-state grinding method. Both copper and zinc species were encapsulated in SBA-15 in high dispersion with the presence of organic template. The mixed homogeneity and interaction between copper and zinc species was enhanced as well with the help of organic template, resulting in the formation of Cu+ species in the reduced catalysts. Moreover, TOFCu(0) linearly increased with the Cu+/Cu0 ratio, indicating that a high proportion of Cu+/Cu0 induced by ZnO should be a key prerequisite to achieve favorable hydrogenation performance. It seems that the Cu+ species originated from Cu-ZnOx species are more active than that from Cu-O-Si species in the activation of MA. These results may provide an inspiration in rational design of Cu-ZnO based catalysts for esters hydrogenation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-30T03:15:27.651931-05:
      DOI: 10.1002/aic.15620
       
  • Bouncing of a bubble at a liquid-liquid interface
    • Authors: K.K. Singh; F. Gebauer, H.-J. Bart
      Abstract: Significant industrial relevance of gas-liquid-liquid flows calls for understanding of their various aspects. This study focusing on one such aspect i.e. interaction of a single bubble with a liquid-liquid interface is aimed at providing the experimental evidence of a hitherto unreported phenomenon of conditional bouncing of a bubble at the interface between two immiscible, initially quiescent liquids. Bouncing of the bubble is observed for two of the six pairs of the immiscible liquids used in the experiments. The data, obtained by conducting experiments with different pairs of the lighter and heavier liquids, bubble diameters and rise heights, suggest that a bubble crossing a liquid-liquid interface is expected to bounce when its approach velocity is less than a threshold value that depends on the interfacial tension and the viscosity of the heavier liquid. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-29T18:00:43.276962-05:
      DOI: 10.1002/aic.15625
       
  • Depositing Lignin on Membrane Surfaces for Simultaneously Upgraded Reverse
           Osmosis Performances: An Upscalable Route
    • Authors: Feng Zhang; Yaping Wu, Weixing Li, Weihong Xing, Yong Wang
      Abstract: Reverse osmosis (RO) have been widely used to produce clean water and there is a strong need to enhance their permeability at no sacrifice of their other performances, e.g. selectivity. We deposit low-cost biopolymer, lignin, onto the surface of RO membranes by a simple filtration method. Lignin is deposited to the membrane surface via both hydrogen bonding and π-π interaction. Lignin deposition reduces the surface roughness of the membrane and enhances its negatively charging, while the surface hydrophilicity is maintained. Surprisingly, water permeation, salt rejection, and fouling resistance of the lignin-deposited membranes are simultaneously improved. More importantly, we demonstrate that this deposition method can be easily extended to modify commercial RO membrane modules, indicating the excellent upscalability of this method. We use the lignin-deposited membranes to treat real effluents of dyeing and papermaking and they perform much better than the virgin, unmodified membranes. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-29T18:00:42.248781-05:
      DOI: 10.1002/aic.15628
       
  • Absorption Behaviors and Kinetic Models Analysis of Li4SiO4 under Various
           CO2 Partial Pressures
    • Authors: Zhang Qi; Peng Dong, Zhang Sai, Ye Qian, Wu Yongqiang, Ni Yanhui
      Abstract: The absorption behaviors of Li4SiO4 sorbent under various CO2 partial pressures and temperatures were investigated through numerical and experimental methods. It was found that Li4SiO4 showed poor absorption capacity at high temperatures (> 525°C) under CO2 partial pressure of 5066 Pa. This phenomenon was explained by the thermodynamic results from FactSage5.5 software. Meanwhile, a modified Jander model based on the double-shell structure of the Li4SiO4 sorbent was developed to describe the absorption kinetic behaviors of CO2 on Li4SiO4. The results showed that the modified Jander model could fit the kinetic experimental data well. Furthermore, the influence of steam on CO2 absorption was also analyzed by the modified Jander model. The results showed that the activation energy in the absorption process with steam was smaller than that without steam, which indicated that the presence of steam could promote the CO2 diffusion in product layer, therefore, improving the sorption capacity. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-29T18:00:40.081231-05:
      DOI: 10.1002/aic.15627
       
  • Stability of Gravitationally Unstable Double Diffusive Transient Boundary
           Layers with Variable Viscosity in Porous Media
    • Authors: Nasser Sabet; Hassan Hassanzadeh, Jalal Abedi
      Abstract: We study the double diffusive convection (DDC) in porous media through linear stability analysis (LSA) and direct numerical simulations (DNS). Unlike the previous studies that assume static solutal or thermal fields, the developed model is able to capture the transient behavior of both fields. We show that under the assumption of static field, the role of Lewis number cannot be distinguished. Under transient fields, we conclude that higher Lewis numbers result in earlier instability of the boundary layers. Moreover, the effect of viscosity contrast is explained in terms of the mobility of the boundary layer. The DNS results confirm the validity of LSA predictions. We also obtain the critical Rayleigh number and show that in the presence of viscosity contrast, it can be much smaller than the conventional limit of 4π 2. This study provides a better understanding of the transient nature of DDC in the presence of viscosity variations. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-29T18:00:35.641534-05:
      DOI: 10.1002/aic.15626
       
  • Direct Silanization of Polyurethane Foams for Efficient Selective
           Absorption of Oil from Water
    • Authors: Sen Xiong; Zhaoxiang Zhong, Yong Wang
      Abstract: Absorption is an effective method to collect oil spills and solvent leakages from water. However, the currently used oil absorbents are still suffering from high cost, tedious preparation, and low recyclability. In this work, we report an extremely simple and low-cost strategy to produce oil absorbents by directly coupling alkoxysilane onto the surface of polyurethane foams. Such direct silanization renders the initially amphiphilic foams a strong hydrophobicity and consequently a water-repelling and oil-absorptive functionality. The silanized foams exhibit highest absorption capacities as well as best recyclability among all polyurethane-based oil absorbents. More practically, the silanized PU foams can be used to recover crude oil spills with an absorption capacity of higher than 75 times of their own weight, and maintain 90% of the initial absorption capacity after 8 times reusage. Interestingly, we invent portable oil suckers for continuous oil absorption from water by filling vacuum cleaners with the silanized foams. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-29T18:00:26.34447-05:0
      DOI: 10.1002/aic.15629
       
  • Unraveling the droplet drying characteristics of crystallization-prone
           mannitol – experiments and modeling
    • Authors: Chen Loon Har; Nan Fu, Eng Seng Chan, Beng Ti Tey, Xiao Dong Chen
      Abstract: Spray-dried mannitol is a potential lactose replacement in pharmaceutical formulations, yet the drying behavior of individual mannitol droplets within the spray chamber has not been fully understood. This work explored the drying characteristics of mannitol by employing the Reaction Engineering Approach (REA) in data analysis. A glass filament single droplet drying technique was used to monitor the changes in droplet temperature, mass and diameter. The drying kinetics data obtained clearly demonstrated the droplet “wet-bulb” period, the crust formation and the crystallization phenomena. The master activation-energy curves developed from REA modeling responded sensitively to varying drying temperatures, which could have led to different crystallization events. The deviation of these plots from the expected norms that do not encounter a phase change was used effectively to discern the physics involved. A REA kinetic model was proposed to assist in process optimization of large-scale spray-drying operations. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-29T17:45:25.166085-05:
      DOI: 10.1002/aic.15624
       
  • Effective Particle Diameters for Simulating Fluidization of Non-spherical
           Particles: CFD-DEM Models vs. MRI Measurements
    • Authors: C. M. Boyce; A. Ozel, N. P. Rice, G. J. Rubinstein, D. J. Holland, S. Sundaresan
      Abstract: CFD-DEM simulations were conducted and compared with magnetic resonance imaging (MRI) measurements1 of gas and particle motion in a 3D cylindrical bubbling fluidized bed. Experimental particles had a kidney-bean-like shape, while particles were simulated as being spherical; to account for non-sphericity, “effective” diameters were introduced to calculate drag and void fraction, such that the void fraction at minimum fluidization (εmf) and the minimum fluidization velocity (Umf) in the simulations matched experimental values. With the use of effective diameters, similar bubbling patterns were seen in experiments and simulations, and the simulation predictions matched measurements of average gas and particle velocity in bubbling and emulsion regions low in the bed. Simulations which did not employ effective diameters were found to produce vastly different bubbling patterns when different drag laws were used. Both MRI results and CFD-DEM simulations agreed with classic analytical theory for gas flow and bubble motion in bubbling fluidized beds. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-27T18:35:21.54145-05:0
      DOI: 10.1002/aic.15623
       
  • Handling Multi-rate and Missing Data in Variable Duration Economic Model
           Predictive Control of Batch Processes
    • Authors: Mudassir M. Rashid; Prashant Mhaskar, Christopher L. E. Swartz
      Abstract: In the present work we consider the problem of variable duration economic model predictive control (EMPC) of batch processes subject to multi-rate and missing data. To this end, we first generalize a recently developed subspace-based model identification approach for batch processes to handle multi-rate and missing data by utilizing the incremental singular value decomposition technique. Exploiting the fact that the proposed identification approach is capable of handling inconsistent batch lengths, the resulting dynamic model is integrated into a tiered EMPC formulation that optimizes process economics (including batch duration). Simulation case studies involving application to the energy intensive electric arc furnace process demonstrate the efficacy of the proposed approach compared to a traditional trajectory tracking approach subject to limited availability of process measurements, missing data, measurement noise and constraints. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-26T19:35:29.783234-05:
      DOI: 10.1002/aic.15619
       
  • A Hybrid Numerical-symbolic Solving Strategy for Equation-oriented Process
           Simulation and Optimization
    • Authors: Fei Zhao; Xi Chen, Lingyu Zhu
      Abstract: The equation-oriented (EO) and sequential modular (SM) methods are two typical approaches for numerical process simulation and optimization. For a large-scale system, the EO method usually suffers from difficulties in variable initialization. The SM method, on the other hand, can suffer from slow convergence and requires experience in choosing appropriate tear variables. In this paper, a novel strategy combining numerical and symbolic approaches is proposed for solving process systems represented by polynomials. First, a digraph method is developed to identify the subset of equations that should be solved simultaneously. Then, a symbolic computation method based on Gröbner basis is proposed to reformulate the simultaneous equations as a completely sequential model with a triangular structure. Last, the reformulated model is solved sequentially without any iterative tearing process. The case studies show that the proposed strategy can significantly improve the solving efficiency and robustness for process simulation and optimization. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-26T19:35:26.419613-05:
      DOI: 10.1002/aic.15622
       
  • Ionic Liquids for Absorption and Separation of Gases: an Extensive
           Database and a Systematic Screening Method
    • Authors: Yongsheng Zhao; Rafiqul Gani, Raja Muhammad Afzal, Xiangping Zhang, Suojiang Zhang
      Abstract: Ionic liquids (ILs) have attracted considerable attention in both the academic and industrial communities for absorbing and separating gases. However, a data-rich and well-structured systematic database has not yet been established, and screening for highly efficient ILs meeting various requirements remains a challenging task. In this study, an extensive database of estimated Henry's law constants of twelve gases in more than ten thousand ILs at 313.15 K is established using the COSMO-RS method. Based on the database, a new systematic and efficient screening method for IL selection for the absorption and separation of gases subject to important target properties is proposed. Application of the database and the screening method is highlighted through case studies involving two important gases separation problems (CO2 from CH4 and C2H2 from C2H4). The results demonstrate the effectiveness of using the screening method together with the database to explore and screen novel ILs meeting specific requirements for the absorption and separation of gases. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-23T18:53:23.323482-05:
      DOI: 10.1002/aic.15618
       
  • Modeling Layered Crystal Growth at Increasing Supersaturation by
           Connecting Growth Regimes
    • Authors: Carl J. Tilbury; Michael F. Doherty
      Abstract: Mechanistic modeling facilitates rational crystallization engineering and design space screening. For an accurate model, the dominant growth mechanism operating on each face must be determined, which is highly dependent on supersaturation. Considering the case of centrosymmetric growth units, we developed and connected existing mechanistic expressions for spiral and two-dimensional-nucleation growth regimes, through application of stationary nucleation rate theory. Our approach enables calculation of crossover supersaturations and forms a framework to model the specific mechanism operating on each face under given crystallization conditions. Increasing supersaturation can change the crystal morphology; as face families switch growth mechanisms, they may grow out of the steady-state shape, or influence its aspect ratio. Application of the model to naphthalene, biphenyl, pentaerythritol and β-HMX shows the ability to capture experimentally observed examples of such supersaturation-dependent crystal habits. This methodology broadens the applicability of mechanistic crystal growth modeling to include higher-supersaturation industrial processes. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-23T18:44:49.588202-05:
      DOI: 10.1002/aic.15617
       
  • The Analysis of Solubility, Absorption Kinetics of CO2 Absorption into
           Aqueous 1-diethylamino-2-propanol Solution
    • Authors: Helei Liu; Min Xiao, Zhiwu Liang, Paitoon Tontiwachwuthikul
      Abstract: In this present work, the CO2 absorption performance of aqueous 1-diethylamino-2-propanol (1DEA2P) solution was studied with respect to CO2 equilibrium solubility, absorption kinetics, and absorption heat. The equilibrium solubility of CO2 in 2M 1DEA2P solution was measured over the temperature range from 298 to 333 K and CO2 partial pressure range from 8 to101 kPa. The absorption kinetics data were developed and analyzed using the base-catalyzed hydration mechanism and ANN models (RBFNN and BPNN models) with an acceptable AAD of 10% for base-catalyzed hydration mechanism, 2.6% for RBFNN model and 1.77% for BPNN model, respectively. The CO2 absorption heat of 1DEA2P was estimated to be -43.6 kJ/mol. In addition, the ion (1DEA2P, 1DEA2PH+, HCO3-, CO32-) speciation plots of the 1DEA2P-CO2-H2O system were developed in order to further understand the reaction process of 1DEA2P with CO2. Based on a comparison with conventional amines (e.g. MEA, DEA, MDEA) and alternative amines (i.e.1DMA2P and DEAB), 1DEA2P exhibited good performance with respect to CO2 equilibrium solubility, reaction kinetics, and CO2 absorption heat. Meanwhile, the overall evaluation of 1DEA2P for application in CCS in terms of absorption and desorption is presented, giving helpful information for the screening of these novel amines. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-23T18:42:05.795761-05:
      DOI: 10.1002/aic.15621
       
  • Full-Physics Simulations of Spray-Particle Interaction in a Bubbling
           Fluidized Bed
    • Authors: Maryam Askarishahi; Mohammad-Sadegh Salehi, Stefan Radl
      Abstract: Numerical simulations of a gas-particle-droplet system were performed using an Euler-Lagrange approach. Models accounting for (i) the interaction between droplets and particles, (ii) evaporation from the droplet spray, as well as (iii) evaporation of liquid from the surface of non-porous particles were considered. The implemented models were verified for a packed bed, as well as other standard flow configurations. The developed models were then applied for the simulation of flow, as well as heat and mass transfer in a fluidized bed with droplet injection. The relative importance of droplet evaporation vs. evaporation from the particle surface was quantified. It was proved that spray evaporation competes with droplet deposition and evaporation from the particle surface. Moreover, we show that adopting a suitable surface coverage model is vital when attempting to make accurate predictions of the particle's liquid content. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-23T18:37:02.374548-05:
      DOI: 10.1002/aic.15616
       
  • Synthetic Saccharomyces cerevisiae-Shewanella oneidensis consortium
           enables glucose-fed high-performance microbial fuel cell
    • Authors: Tong Lin; Xue Bai, Yidan Hu, Bingzhi Li, Ying-Jin Yuan, Hao Song, Yun Yang, Jingyu Wang
      Abstract: Microbial fuel cells (MFCs) were green and sustainable bio-electrochemical reactors for simultaneous wastewater treatment and electricity harvest from organic wastes. However, exoelectrogens, such as Shewanella and Geobacter being widely studied in MFCs, could only use a limited spectrum of carbon sources. To expand the carbon source range being used in MFCs, we herein rationally designed a glucose-fed fungus-bacteria microbial consortium including a fermenter (Saccharomyces cerevisiae) in which the ethanol pathway was knocked out and the lactic acid biosynthesis pathway from Bovin was introduced into S. cerevisiae, and an exoelectrogen (Shewanella oneidensis MR-1). We optimized the co-culturing conditions of the microbial consortium to achieve an optimal coordination between carbon source metabolism of the fermenter and extracellular electron transfer of the exoelectrogen, such that lactate, the metabolic product of glucose by the recombinant S. cerevisiae, was continuously supplied to S. oneidensis in a constant level until glucose exhaustion. This metabolic coordination between the fermenter and the exoelectrogen enabled bioelectricity production in a glucose-fed MFC. Furthermore, a porin protein encoded by oprF gene from Pseudomonas aeruginosa was incorporated into the outer membrane of S. oneidensis to enhance membrane permeability and its hydrophobicity, which in turn facilitated its biofilm formation and power generation. The glucose-fed MFC inoculated with the recombinant S. cerevisiae-recombinant S. oneidensis generated a maximum power density of 123.4 mW/m2, significantly higher than that of recombinant S. cerevisiae-wild-type S. oneidensis (71.5 mW/m2). Our design strategy of synthetic microbial consortia was highly scalable to empower the possibility of a wide range of carbon sources being used in MFCs, e.g., xylose, cellulosic biomass, and recalcitrant wastes. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-12-23T11:45:25.726289-05:
      DOI: 10.1002/aic.15611
       
  • Dissolution of Semicrystalline Polymer Fibers: Numerical Modeling and
           Parametric Analysis
    • Authors: Mohammad Ghasemi; Abhiram Y. Singapati, Marina Tsianou, Paschalis Alexandridis
      Abstract: The solvent processing of polymers is significantly constrained by polymer chain crystallinity. A phenomenological model is developed here that captures the phenomena governing the dissolution of semicrystalline polymers, e.g., solvent penetration, transformation from crystalline to amorphous domains, specimen swelling, and polymer chain untangling. The model is validated for the case of cellulose fiber swelling and dissolution in an ionic liquid. A parametric sensitivity analysis is carried out to assess the impact of decrystallization rate constant, disentanglement rate, concentration dependence of solvent diffusivity, disentanglement threshold, and thickness of external boundary layer on the swelling and dissolution of semicrystalline polymer fibers. The rate of dissolution after attaining maximum swelling is found to be mainly controlled by the polymer chain disentanglement rate. The insights obtained from this study would facilitate the design of efficient solvent systems and processing conditions for the dissolution of semicrystalline polymers such as cellulose, polyglycolic acid, and polyesters. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-20T10:59:51.384474-05:
      DOI: 10.1002/aic.15615
       
  • Quantification of metal-acid balance in hydroisomerization catalysts: A
           step further towards catalyst design
    • Authors: Pedro S. F. Mendes; João M. Silva, M. Filipa Ribeiro, Pascal Duchêne, Antoine Daudin, Christophe Bouchy
      Abstract: A methodology was developed to interpret the results of n-paraffins hydroisomerization over bifunctional catalysts based on two simple kinetic models used consecutively. Firstly, a macrokinetic model was used to obtain the corresponding turnover frequency over the acid sites and the maximum of C16 isomer yield. Secondly, a dual-function model was used to correlate these catalytic descriptors to the ratio of metal to acid sites of the catalyst. To illustrate the methodology, Pt/HBEA and Pt/HUSY catalysts with different Pt loadings were evaluated. The impact of metal-acid balance on the catalytic turnover frequency and the maximal C16 isomer yield were adequately captured for the bifunctional HUSY and HBEA catalysts. Moreover, the parameters of the dual-function model revealed to be intrinsic to the catalytic properties of the zeolite under the scope. This methodology is believed to be of interest for information-driven catalyst design for the hydroisomerization of n-paraffins. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-16T02:25:36.021549-05:
      DOI: 10.1002/aic.15613
       
  • Automatic Detection of Contact Lines in Slot Coating Flows
    • Authors: Hyeyoung Hong; Jaewook Nam
      Abstract: Slot coating is a versatile method used to manufacture thin films at high speed. The success of the method lies in controlling a coating flow surrounded by upstream and downstream menisci. The meniscus edges that are in contact with either the die lips or the substrate surfaces are called contact lines. Visualizations of such lines are important in coating flow research because their shapes and locations are sensitive to operating conditions. In this study, we propose a robust image analysis algorithm for images acquired from flow visualizations. The images are dissected into three regions with different characteristics that need to be treated using different pre-processing techniques. A standard optimal edge detector is then sufficient to capture the contact lines, and post-processing steps can be simplified. We also highlight two applications of the proposed algorithm: coating windows, and transient behaviors under external disturbances. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-16T02:25:30.566584-05:
      DOI: 10.1002/aic.15612
       
  • Mass and heat transfer behavior of oscillating helical coils in relation
           to heterogeneous reactor design
    • Authors: M. H. Abdel-Aziz; I. Nirdosh, G. H. Sedahmed
      Abstract: Rates of mass and heat transfer at vibrating helical coils were studied by the electrochemical technique with the object of using helical coils as heat exchanger/reactor for conducting liquid – solid diffusion controlled reactions. Variables studied were frequency and amplitude of vibration, tube diameter and superimposed axial flow velocity. The data for vibrating coil (batch reactor) were correlated for 59 
      PubDate: 2016-12-16T02:25:27.333646-05:
      DOI: 10.1002/aic.15614
       
  • Mathematical Modeling of Molecular Weight Distribution in Miniemulsion
           Polymerization with Oil-Soluble Initiator
    • Authors: Claudia A. Capeletto; Cristiane Costa, Claudia Sayer, Pedro H. H. Araújo
      Abstract: A mathematical model for the study of reaction kinetics and molecular weight distributions in miniemulsion polymerization systems with oil-soluble initiators is presented. The mathematical model allows the computation of the evolution of the complete molecular weight distribution with chain lengths of up to 100,000 mers in miniemulsion polymerization by direct integration in reasonable computational time. Also, no restriction in the kinetic regime is needed, as the model is able to represent both compartmentalized and pseud-bulk systems. The model was validated with experimental results for methyl methacrylate and styrene homopolymerizations, with two different oil-soluble initiators, and adequately represented both the kinetics and molecular weight distributions of these systems. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-10T17:55:35.032119-05:
      DOI: 10.1002/aic.15608
       
  • Analysis of Flow and Mixing in Screw Elements of Co-Rotating Twin-Screw
           Extruders via SPH
    • Authors: Andreas Eitzlmayr; Josip Matić, Johannes Khinast
      Abstract: Due to its meshless nature, the smoothed particle hydrodynamics method (SPH) provides high potential for the simulation of free-surface flows and mixing in complex geometries. We used SPH to analyze the flow inside five typical screw elements of co-rotating twin-screw extruders, two conveying elements, two kneading elements and a mixing element. Our results show conveying capabilities, pressure generation and power input for various operation states, completely and partially filled. We conducted a detailed mixing analysis based on tracer particles, which yielded the time evolution of the intensity of segregation for different tracers. From that, we determined exponential mixing rates, which describe the relative decrease of the intensity of segregation per screw revolution and characterize the mixing performance in different operation states. This provides valuable input information for simplified models of extruders, which are relevant to industrial applications and can significantly contribute to the efficient design, optimization and scale-up of extruders. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-10T17:55:30.920913-05:
      DOI: 10.1002/aic.15607
       
  • “CFD studies coupling hydrodynamics and solid-liquid mass transfer in
           slug flow for matter removal from tube walls”
    • Authors: M.C.F. Silva; J.D.P. Araújo, J.B.L.M. Campos
      Abstract: Organic matter deposition on internal surfaces constitutes a drawback that impairs the efficiency of several industrial processes. To overcome this problem, sparging a train of bubbles could be useful since its presence strongly increases the wall shear stress. A detailed numerical mass transfer study between a finite soluble wall and the liquid around a rising Taylor bubble was performed, simultaneously solving velocity and concentration fields. The bubble passage throws solute backwards and is responsible for radial dispersion. There is also an increase in the transfer rate with enhancements between 10-20% (depending on liquid average velocity and bubble length) compared to single-phase flow. Mass transfer coefficients along the different hydrodynamic regions around the bubble - nose, liquid film and wake – were characterized and their values compared with those from literature. The results suggest a promising potential of bubble train flow to enhance organic matter removal from walls in biological systems. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-10T17:55:27.486651-05:
      DOI: 10.1002/aic.15610
       
  • Multi-objective optimization superimposed model-based process design of an
           enzymatic hydrolysis process
    • Authors: Philip Zitzewitz; Georg Fieg
      Abstract: The concepts of green process engineering and rigorous model-based approaches have proven to be highly beneficial in process engineering. Although a combination of these two principles thus appears extremely promising, it is not found very commonly in literature. The very high complexity resulting from this combination poses great challenges for the process design and design engineers. Therefore, this work presents an innovative methodology for the model-based process design with superimposed multi-objective optimization for an exemplary process. This process for the enzymatic hydrolysis of fatty acid methyl ester combines several aspects of green process engineering and represents an exemplary process with an enzymatic liquid-liquid-solid reaction system. The optimization results based on operating and investment costs reveal important insights on the exemplary process and highlight the great advantages of the developed methodology as a profound basis for academic and industrial process design purposes. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-10T17:55:23.733607-05:
      DOI: 10.1002/aic.15609
       
  • Association Extraction for Vitamin E Recovery from Deodorizer Distillate
           by in-situ Formation of Deep Eutectic Solvent
    • Authors: Lei Qin; Jiangsheng Li, Hongye Cheng, Lifang Chen, Zhiwen Qi, Weikang Yuan
      Abstract: An innovative intensified vitamin E (VE) recovery process from the methylated oil deodorizer distillates (MODDs) was proposed, where VE was in-situ transferred into a deep eutectic solvent (DES) with an organic salt. To design the process, the chlorine based quaternary ammonium salts were primarily investigated, and [N4,4,4,4]Cl was selected as an association solvent which can efficiently form DES with α-tocopherol of the representative compound of VE. Based on the determined phase diagram of the DES freezing points, four phase regions were classified, and the effect of the [N4,4,4,4]Cl/tocopherol ratio and temperature on the extraction performance and phase transformation was figured out. Moreover, an intensified association extraction process via in-situ forming DES of α-tocopherol with [N4,4,4,4]Cl was designed and validated by experiments. VE products were finally obtained from both model MODD (purity of 99.63%) and practical MODDs (purity of > 79.18%), which verifies the excellent extraction efficiency for the proposed recovery method. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-10T17:50:24.464239-05:
      DOI: 10.1002/aic.15606
       
  • Novel Method for determination of Gas Solubilities in Low Vapor Pressure
           Liquids
    • Authors: L.F. Zubeir; P.J.L. Lipman, N. Awwad, C. J. Peters, M.C. Kroon, J. van der Schaaf
      Abstract: A modified version of a standard device for measuring gas adsorption and desorption isotherms and surface area of adsorbents and catalysts (ASAP (Accelerated Surface Area and Porosimetry System) 2020, Micromeritics USA) is used for the first time to measure gas solubilities (i.e. CO2) in low vapor pressure liquids (i.e. the IUPAC standard ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C6mim][Tf2N])) in the Henry's law region. The solubility data are in very good agreement with the reported data in literature. Furthermore, the Henry's law constants are calculated from the solubility data and compared to the experimental data found in literature. The results from this study demonstrate that Micromeritics ASAP 2020 is a suitable apparatus for gas absorption by solvents with reduced vapor pressures. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-07T08:06:30.202143-05:
      DOI: 10.1002/aic.15603
       
  • Robustness of Bioprocess Feedback Control to Biodiversity
    • Authors: Francis Mairet; Olivier Bernard
      Abstract: The design of control laws for bioprocesses are generally based on simplified single-species models. Biodiversity is nonetheless inherent in any bioreactor where contamination leads to a mixture of different species or strains. Here we propose to define and study the robustness to biodiversity of bioprocess control laws: given a control law designed for one species, what happens when additional species are present? We illustrate our approach with a well used control law which regulates substrate concentration using measurement of growth activity. Depending on the properties of the additional species, the control law can lead to the required objective, but also to an undesired monospecies equilibrium point, coexistence, or even a failure point. Finally, we show that, for this case, the robustness can be improved by a saturation of the control. Robustness to biodiversity is a difficult issue which should be better understood and accounted for in the control design. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-07T08:00:50.843117-05:
      DOI: 10.1002/aic.15604
       
  • Game Theory Approach to Optimal Design of Shale Gas Supply Chains with
           Consideration of Economics and Life Cycle Greenhouse Gas Emissions
    • Authors: Jiyao Gao; Fengqi You
      Abstract: This paper addresses the optimal design of a non-cooperative shale gas supply chain based on a game theory approach. Instead of assuming a single stakeholder as in centralized models, we consider different stakeholders, including the upstream shale gas producer and the midstream shale gas processor. Following the Stackelberg game, the shale gas producer is identified as the leader, whose objectives include maximizing its net present value (NPV) and minimizing the life cycle greenhouse gas (GHG) emissions. The shale gas processor is identified as the follower that takes actions after the leader to maximize its own NPV. The resulting problem is a multiobjective mixed-integer bilevel linear programming problem, which cannot be solved directly using any off-the-shelf optimization solvers. Therefore, an efficient projection-based reformulation and decomposition algorithm is further presented. Based on a case study of the Marcellus shale play, the non-cooperative model not only captures the interactions between stakeholders but also provides more realistic solutions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-07T07:55:30.971393-05:
      DOI: 10.1002/aic.15605
       
  • Multiple isolas in steady-state characteristics of fluidized bed catalytic
           reactors
    • Authors: Katarzyna Bizon
      Abstract: Steady-state characteristics of a catalytic fluidized bed reactor are analyzed. A two-phase bubbling model is employed for the description of a fluidized bed of a catalyst. Particular attention is focused on the theoretical and technological consequences of a newly observed steady-state behavior. Features of the model are presented in terms of steady-state structures, stability, solution multiplicity, and process efficiency. The possibility of an occurrence of multiple isolas of steady states is demonstrated for two simple kinetic models. Depending on the multiplicity region they belong to, multiple isolas are referred to as first type or second type isolas. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-07T07:51:44.292796-05:
      DOI: 10.1002/aic.15599
       
  • Modelling of the Desulfation Process in NOx Storage and Reduction
           Catalysts
    • Authors: F.-A. Lafossas; C. Manetas, A. Mohammadi, G. Koltsakis, M. Iida, K. Yoshida
      Abstract: One of the major challenges for the NOx Storage and Reduction (NSR) Catalysts technology used in automotive exhaust remains the sulfur susceptibility, which calls for efficient desulfation strategies. In the present study the sulfation and desulfation processes are systematically studied via measurements and mathematical modelling of the physicochemical processes. The role of oxygen storage which influences the reducing agents availability for desulfation is explained and a respective reaction model is presented. The bulk oxygen storage component appears to be involved in sulfur storage, which further emphasizes the importance of oxygen – sulfur storage interactions. Next, the observed release of sulfur species under lean mode is discussed along with a proposed reaction mechanism which involves SO2 formation via O2 reaction with elemental sulfur on the surface. The parameters of the complex reaction model are calibrated in order to reproduce the observed trends at least in a qualitative manner. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-07T07:51:43.348379-05:
      DOI: 10.1002/aic.15600
       
  • Enzymatic Catalyzed Reactive Dividing Wall Column: Experiments and Model
           Validation
    • Authors: Torben Egger; Georg Fieg
      Abstract: A novel process for the integration of chemical reaction and product separation is proposed: the enzymatic catalyzed reactive dividing wall column (eRDWC). The eRDWC combines the highly integrated and complex reactive dividing wall column (RDWC) with the use of a very selective enzymatic catalyst. This apparatus enables the simultaneous production and separation of up to 4 pure product streams. Comprehensive experiments with the reference system of a hexanol and butyl acetate transesterification in a DN 65 pilot scale column show the feasibility of stable steady state operations for this process. A rigorous model for the plant design of an eRDWC wall column is developed. The reaction kinetics and vapor-liquid-equilibria for the reference system are measured and implemented in the model. The model is successfully validated using the acquired experimental data. The application of enzymes in continuous reactive distillation processes has the potential to increase the selectivity at milder process conditions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-07T07:51:40.440241-05:
      DOI: 10.1002/aic.15598
       
  • Highly Efficient Removal of Bulky Tannic Acid by Millimeter-sized
           Nitrogen-doped Mesoporous Carbon Beads
    • Authors: Yanping Chong; Ke Liu, Yu Liu, Jitong Wang, Wenming Qiao, Licheng Ling, Donghui Long, Zhishan Bai
      Abstract: Millimeter-sized nitrogen-doped mesoporous carbon beads (NMCBs) with a controllable nitrogen content are synthesized for the first time via a suspension-polymerization assisted hard templating method. In contrast to conventional activated carbons, NMCBs exhibit outstanding structural advantages, including macroscopic morphology, a developed mesoporous structure and enriched surface chemistry. When used as adsorbents for the removal of the bulky organic pollutant tannic acid, these NMCBs demonstrated fast adsorption kinetics and very high adsorption capacity. The adsorption capacity strongly depends on the nitrogen content doped into the carbon framework. At a nitrogen content of 4.1 wt%, the adsorption capacity reaches 318 mg/g. The molecular mechanics simulation and zeta potential measurements suggest that the enhanced adsorption by nitrogen doping may be due to the electrostatic attraction between the nitrogen functional groups and the phenol groups of tannic acid. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-07T07:51:20.990262-05:
      DOI: 10.1002/aic.15601
       
  • Integrated Adsorbent-Process Optimization for Carbon Capture and
           Concentration Using Vacuum Swing Adsorption Cycles
    • Authors: Maninder Khurana; Shamsuzzaman Farooq
      Abstract: A novel approach for integrated adsorbent and process design is proposed. The traditional PSA/VSA process optimization for chosen objectives, where operating conditions are the decision variables, and CO2 purity and recovery are constraints, is expanded to include adsorbent isotherm characteristics as additional decision variables. Two VSA cycles, namely a 4-step process1, currently known to have the lowest energy consumption for CO2 capture and concentration (CCC), and a 6-step process2, recently proven to have a wider operating window for the evacuation pressure, have been investigated in the current study. The integrated optimization results simultaneously provide the lower bound of minimum energy and upper bound of maximum productivity for CCC achievable from the two VSA processes along with the operating conditions and the corresponding isotherm shapes necessary to achieve them. It may be viewed as an enabler for adsorbent design or expedient adsorbent search by process inversion. This article is protected by copyright. All rights reserved.
      PubDate: 2016-12-07T07:51:18.441074-05:
      DOI: 10.1002/aic.15602
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • Review of the important challenges and opportunities related to modeling
           of mammalian cell bioreactors
    • Authors: Parham Farzan; Biren Mistry, Marianthi G. Ierapetritou
      Pages: 398 - 408
      Abstract: Industrialization of mammalian cell culture has been achieved by integrating knowledge from several applying core concepts of chemical engineering, cellular and molecular biology, and biochemistry. Modeling has been applied to biological and physical processes to gain additional insights into such processes. This article covers modeling of the bioreactor and metabolic processes as it applies to bioprocess. Hydrodynamics of a bioreactor is briefly described while additional focus is given to gas-liquid mass transfer. Biological modeling is presented in the order of increasing complexity. First steady state models are presented followed by dynamic models, cybernetic models, and finally bioreactor integrated models. The closing discussion summarizes challenges of implementation of model-based approaches in the biopharmaceutical industry. © 2016 American Institute of Chemical Engineers AIChE J, 63: 398–408, 2017
      PubDate: 2016-08-17T14:40:32.465231-05:
      DOI: 10.1002/aic.15442
       
  • Effect of potassium ion on the stability and release rate of hydrogen
           peroxide encapsulated in silica hydrogels
    • Authors: Ezgi Melis Dogan; Fulya Sudur Zalluhoglu, Nese Orbey
      Pages: 409 - 417
      Abstract: Hydrogen peroxide (H2O2) is encapsulated in silica hydrogels using sol-gel method and the effects of the K+ : Na+ ion ratio on gelation time, hydrogel structure, stability, and release rate of H2O2 were investigated. As the amount of K+ ions increased relative to the amount of Na+ ions at the same pH, the gel structure became less compact and the pore diameter increased. Hydrogen peroxide retention values up to 90 and 80% were observed at the end of 7 and 20 days, respectively, in the presence of K+ ions at low pH values when the initial H2O2 concentration was 19.9 wt %. Release rate of hydrogen peroxide decreased with decreasing pH for the two K+ : Na+ ion ratios studied. This work presents an environmentally friendly, low cost, and easy to scale up method to increase the stability of high initial concentrations of H2O2 at room temperature and customize the release rate. © 2016 American Institute of Chemical Engineers AIChE J, 63: 409–417, 2017
      PubDate: 2016-07-22T08:35:44.62765-05:0
      DOI: 10.1002/aic.15406
       
  • CFD–DEM simulation of tube erosion in a fluidized bed
    • Authors: Yongzhi Zhao; Lei Xu, Jinyang Zheng
      Pages: 418 - 437
      Abstract: The erosion of the immersed tubes in a bubbling-fluidized bed is studied numerically using an Eulerian–Lagrangian approach coupling with a particle-scale erosion model. In this approach, the motion of gas and particles is simulated by the CFD–DEM method, and an erosion model SIEM (shear impact energy model) is proposed to predict the erosion of the tubes. The model is validated by the good agreement of the simulation results and previous experimental data. By analyzing the simulation results, some characteristics of the tube erosion in the fluidized bed are obtained, such as the distribution of the erosion rate around the tube, the variation of the erosion rate with the position of the tube, the effect of the friction coefficient of particles on the erosion, the relationship between the maximum and the average erosion rate, etc. The microscale behavior of particles around the tubes is also revealed and the linear relationship between the erosion and the shear impact energy is confirmed by the simulation results and experiment. The agreement between simulation and experiment proves that the microscale approach proposed in this article has high accuracy for predicting erosion of the tubes in the fluidized bed, and has potential to be applied to modeling the process in other chemical equipment facing solid particle erosion. © 2016 American Institute of Chemical Engineers AIChE J, 63: 418–437, 2017
      PubDate: 2016-07-14T09:55:41.01972-05:0
      DOI: 10.1002/aic.15398
       
  • A compartmental CFD-PBM model of high shear wet granulation
    • Authors: Xi Yu; Michael J. Hounslow, Gavin K. Reynolds, Anders Rasmuson, Ingela Niklasson Björn, Per J. Abrahamsson
      Pages: 438 - 458
      Abstract: The conventional, geometrically lumped description of the physical processes inside a high shear granulator is not reliable for process design and scale-up. In this study, a compartmental Population Balance Model (PBM) with spatial dependence is developed and validated in two lab-scale high shear granulation processes using a 1.9L MiPro granulator and 4L DIOSNA granulator. The compartmental structure is built using a heuristic approach based on computational fluid dynamics (CFD) analysis, which includes the overall flow pattern, velocity and solids concentration. The constant volume Monte Carlo approach is implemented to solve the multi-compartment population balance equations. Different spatial dependent mechanisms are included in the compartmental PBM to describe granule growth. It is concluded that for both cases (low and high liquid content), the adjustment of parameters (e.g. layering, coalescence and breakage rate) can provide a quantitative prediction of the granulation process. © 2016 American Institute of Chemical Engineers AIChE J, 63: 438–458, 2017
      PubDate: 2016-07-15T09:40:46.374449-05:
      DOI: 10.1002/aic.15401
       
  • Efficient synthesis of iron nanoparticles by self-agglomeration in a
           fluidized bed
    • Authors: Jun Li; Jing Kong, Qingshan Zhu, Hongzhong Li
      Pages: 459 - 468
      Abstract: A two-stage, fluidized reduction route is proposed to synthesize iron nanoparticles (NPs), with the aim of enhancing the quality of fluidization and preventing sintering activity. At both low and high temperatures, the degree of metallization η is approximately 80% due to the defluidization. Defluidization is mainly caused by the rapid sintering of the newly formed Fe NPs. The proposed two-stage fluidization approach successfully resolves the defluidization problem through the self-agglomeration of nanoparticles cultivated at low temperatures. These self-agglomerated NPs showed an improved resistance to sintering at high temperatures. The high-purity Fe NPs prepared by this approach exhibited excellent combustion activity, indicative of the potential as oxygen carriers in chemical looping combustion systems. © 2016 American Institute of Chemical Engineers AIChE J, 63: 459–468, 2017
      PubDate: 2016-07-20T09:01:00.805092-05:
      DOI: 10.1002/aic.15402
       
  • A simple model for predicting solid concentration distribution in
           binary-solid liquid fluidized beds
    • Authors: Zhengbiao Peng; Behdad Moghtaderi, Elham Doroodchi
      Pages: 469 - 484
      Abstract: A simple mathematical model for predicting the solid concentration profile in binary-solid liquid fluidized beds is presented. The main assumption is that the solid concentration distribution follows the logistic function, which is supported by the literature. Various equations have been derived to solve key system quantities (e.g., bed expansion height, length and position of the transition zone). In contrast to previous models that often involve adjustable parameters and strongly rely on the availability of experimental data, the present model only requires inputs of fluid and particle properties, operating conditions, and correlations for dispersion and slip velocity. The results showed that the model is applicable to different binary-solid systems that have size and/or density differences. The model's capability of predicting the layer inversion phenomenon has also been demonstrated. The model is simple but proves capable of accurately predicting key information for the design, operation and scale up of liquid fluidized beds. © 2016 American Institute of Chemical Engineers AIChE J, 63: 469–484, 2017
      PubDate: 2016-07-27T10:25:34.645809-05:
      DOI: 10.1002/aic.15420
       
  • Improving the operational stability of the multi-chamber spout-fluid bed
           via the insertion of a submerged partition plate
    • Authors: Shiliang Yang; Liangqi Zhang, Yuhao Sun, Jia Wei Chew
      Pages: 485 - 500
      Abstract: The effect of a submerged partition plate on improving the gas–solid flow robustness and stability in a three-dimensional spout-fluid bed with multiple inter-connected chambers is numerically investigated by means of computational fluid dynamics coupled with discrete element method (CFD-DEM). Notably, multiple-chamber beds are necessary in scaling up the spout-fluid bed. The influence of plate height on gas–solid distribution, spout-annulus interaction and chamber interaction are also studied to optimize the design. The results demonstrate that inserting a partition plate with height above a certain threshold can effectively improve the stability of spouting and uniformly re-distribute the flux load in each chamber, giving rise to parallel fountains and lower circulation flux of the solid phase. Results indicate that the plate height should be at least 80% of the packed bed height investigated, with the most optimal being about 92% based on steady spouting, and the maximum solid and gas exchanging fluxes between the chambers. © 2016 American Institute of Chemical Engineers AIChE J, 63: 485–500, 2017
      PubDate: 2016-07-27T09:35:30.3514-05:00
      DOI: 10.1002/aic.15427
       
  • Simulation of dry powder inhalers: Combining micro-scale, meso-scale and
           macro-scale modeling
    • Authors: Berend van Wachem; Kyrre Thalberg, Johan Remmelgas, Ingela Niklasson-Björn
      Pages: 501 - 516
      Abstract: The flow of carrier particles, coated with active drug particles, is studied in a prototype dry powder inhaler. A novel, multiscale approach consisting of a discrete element model (DEM) to describe the particles coupled with a dynamic large eddy simulation (LES) model to describe the dynamic nature of the flow is applied. The model consists of three different scales: the micro-scale, the meso-scale, and the macro-scale. At the micro-scale, the interactions of the small active drug particles with larger carrier particles, with the wall, with the air flow, and with each other is thoroughly studied using discrete element modeling and detailed computational fluid dynamics (CFD), i.e., resolving the flow structures around the particles. This has led to the development of coarse-grained models, describing the interaction of the small active drug particles at the larger scales. At the meso-scale the larger carrier particles, and all of their interactions are modeled individually using DEM and CFD-LES. Collisions are modeled using a visco-elastic model to describe the local deformation at each point of particle-particle contact in conjunction with a model to account for cohesion. At the macro-scale, simulations of a complete prototype inhaler are carried out. By combining the relevant information of each of the scales, simulations of the inhalation of one dose from a prototype inhaler using a patient relevant air flow profile show that fines leave the inhaler faster than the carrier particles. The results also show that collisions are not important for particle-particle momentum exchange initially but become more important as the particles accelerate. It is shown that for the studied prototype inhaler the total release efficiency of the fine particles is between 10 and 30%, depending on the Hamaker constant, using typical settings for the properties of both particles. The results are also used to study regions of recirculation, where carrier particles can become trapped, and regions where fines adhere to the wall of the device. © 2016 American Institute of Chemical Engineers AIChE J, 63: 501–516, 2017
      PubDate: 2016-07-29T14:25:41.300309-05:
      DOI: 10.1002/aic.15424
       
  • A novel feasibility analysis method for black-box processes using a radial
           basis function adaptive sampling approach
    • Authors: Zilong Wang; Marianthi Ierapetritou
      Pages: 532 - 550
      Abstract: Feasibility analysis is used to determine the feasible region of a multivariate process. This can be difficult when the process models include black-box constraints or the simulation is computationally expensive. To address such difficulties, surrogate models can be built as an inexpensive approximation to the original model and help identify the feasible region. An adaptive sampling method is used to efficiently sample new points toward feasible region boundaries and regions where prediction uncertainty is high. In this article, cubic Radial Basis Function (RBF) is used as the surrogate model. An error indicator for cubic RBF is proposed to indicate the prediction uncertainty and is used in adaptive sampling. In all case studies, the proposed RBF-based method shows better performance than a previously published Kriging-based method. © 2016 American Institute of Chemical Engineers AIChE J, 63: 532–550, 2017
      PubDate: 2016-06-28T10:30:33.540672-05:
      DOI: 10.1002/aic.15362
       
  • A generalized stochastic modelling approach for crystal size distribution
           in antisolvent crystallization operations
    • Authors: Roberto Baratti; Stefania Tronci, Jose A. Romagnoli
      Pages: 551 - 559
      Abstract: A generalized formulation for the development of stochastic models to predict the crystal size distribution (CSD) in antisolvent crystallization processes is proposed. Exploiting the result of the noise induced dynamic in stochastic processes, new results are provided to represent the CSD as function of the operational parameters. The generalized formulation enables the full description of the CSD using nonlinear drift term in conjunction with multiplicative noise, i.e., state dependent diffusion. For the first time a deterministic nonlinear differential equation to represent the mean and most probable size (mode) time evolution as function of the model parameters is provided. Furthermore, the analytical solution of the asymptotic probability distribution of the CSD can also be obtained. Finally, a global model formulation is finally presented by defining relationships between the model parameters and the operating conditions. Experimental results and validations are provided using the ternary system of NaCl, water, and ethanol. © 2016 American Institute of Chemical Engineers AIChE J, 63: 551–559, 2017
      PubDate: 2016-06-28T10:05:32.746896-05:
      DOI: 10.1002/aic.15372
       
  • Integrated design of agricultural and industrial processes: A case study
           of combined sugar and ethanol production
    • Authors: Kotaro Ouchida; Yasuhiro Fukushima, Satoshi Ohara, Akira Sugimoto, Masahiko Hirao, Yasunori Kikuchi
      Pages: 560 - 581
      Abstract: Bioethanol production from molasses has advantages in greenhouse gas emissions because of its energy acquisition from bagasse. However, the improvement of bioethanol productivity is challenging; while each elemental technology option can be greatly improved, the trade-offs between the production of raw sugar and bioethanol are complex. This issue should be addressed through the optimization of the whole system, including both agricultural and industrial processes. In this study, we constructed a model of combined raw sugar and bioethanol production from sugarcane considering agricultural and industrial technology options. Data were acquired through a detailed investigation of actual sugar mills. Case studies on the redesign of combined raw sugar and bioethanol production demonstrated that the simultaneous implementation of both technology options increases production of food, materials, and energy from plant-derived renewable resources, thus demonstrating the effectiveness of the interdisciplinary approach. © 2016 American Institute of Chemical Engineers AIChE J, 63: 560–581, 2017
      PubDate: 2016-06-30T11:27:30.926988-05:
      DOI: 10.1002/aic.15374
       
  • Optimal processing network design under uncertainty for producing fuels
           and value-added bioproducts from microalgae: Two-stage adaptive robust
           mixed integer fractional programming model and computationally efficient
           solution algorithm
    • Authors: Jian Gong; Fengqi You
      Pages: 582 - 600
      Abstract: Fractional metrics, such as return on investment (ROI), are widely used for performance evaluation, but uncertainty in the real market may unfortunately diminish the results that are based on nominal parameters. This article addresses the optimal design of a large-scale processing network for producing a variety of algae-based fuels and value-added bioproducts under uncertainty. We develop by far the most comprehensive processing network with 46,704 alternative processing pathways. Based on the superstructure, a two-stage adaptive robust mixed integer fractional programming model is proposed to tackle the uncertainty and select the robust optimal processing pathway with the highest ROI. Since the proposed problem cannot be solved directly by any off-the-shelf solver, we develop an efficient tailored solution method that integrates a parametric algorithm with a column-and-constraint generation algorithm. The resulting robust optimal processing pathway selects biodiesel and poly-3-hydroxybutyrate as the final fuel and bioproduct, respectively. © 2016 American Institute of Chemical Engineers AIChE J, 63: 582–600, 2017
      PubDate: 2016-07-05T11:45:34.979619-05:
      DOI: 10.1002/aic.15370
       
  • Half order plus time delay (HOPTD) models to tune PI controllers
    • Authors: Jietae Lee; Yongjeh Lee, Dae Ryook Yang, Thomas F. Edgar
      Pages: 601 - 609
      Abstract: Methods based on the first-order plus time delay (FOPTD) model are very popular for tuning proportional-integral (PI) controllers. The FOPTD model-based methods are simple and their utility has been proved with many successful applications to a wide range of processes in practice. However, even for some overdamped processes where the FOPTD model seems to be applied successfully, these empirical FOPTD model-based methods can fail to provide stable tuning results. To remove these drawbacks, a PI controller tuning method based on half-order plus time delay (HOPTD) model is proposed. Because FOPTD model-based methods can be applied to higher order processes, the proposed HOPTD model-based method can be applied to higher order processes as well. It does not require any additional process information compared to the FOPTD model-based method and hence can be used for overdamped processes in practice, complementing the traditional FOPTD model-based methods. © 2016 American Institute of Chemical Engineers AIChE J, 63: 601–609, 2017
      PubDate: 2016-07-11T09:50:28.699716-05:
      DOI: 10.1002/aic.15394
       
  • General optimization model for the energy planning of industries including
           renewable energy: A case study on oil sands
    • Authors: Mohamed Elsholkami; Ali Elkamel
      Pages: 610 - 638
      Abstract: A multi-period optimization model is developed for the energy procurement planning of industries including renewable energy. The model is developed with the objective of identifying the optimal set of energy supply technologies to satisfy a set of demands (e.g., power, heat, hydrogen, etc.) and emission targets at minimum cost. Time dependent parameters are incorporated in the model formulation, including demands, fuel prices, emission targets, carbon tax, lead time, etc. The model is applied to a case study based on the oil sands operations over the planning period 2015–2050. Various production alternatives were incorporated, including renewable, nuclear, conventional and gasification of alternative fuels. The results obtained indicated that the energy optimization model is a practical tool that can be utilized for identifying the key parameters that affect the operations of energy-intensive industrial operations, and can further assist in the planning and scheduling of the energy for these industries. © 2016 American Institute of Chemical Engineers AIChE J, 63: 610–638, 2017
      PubDate: 2016-07-15T12:20:54.993618-05:
      DOI: 10.1002/aic.15393
       
  • Moving horizon closed-loop production scheduling using dynamic process
           models
    • Authors: Richard C. Pattison; Cara R. Touretzky, Iiro Harjunkoski, Michael Baldea
      Pages: 639 - 651
      Abstract: The economic circumstances that define the operation of chemical processes (e.g., product demand, feedstock and energy prices) are increasingly variable. To maximize profit, changes in production rate and product grade must be scheduled with increased frequency. To do so, process dynamics must be considered in production scheduling calculations, and schedules should be recomputed when updated economic information becomes available. In this article, this need is addressed by introducing a novel moving horizon closed-loop scheduling approach. Process dynamics are represented explicitly in the scheduling calculation via low-order models of the closed-loop dynamics of scheduling-relevant variables, and a feedback connection is built based on these variables using an observer structure to update model states. The feedback rescheduling mechanism consists of, (a) periodic schedule updates that reflect updated price and demand forecasts, and, (b) event-driven updates that account for process and market disturbances. The theoretical developments are demonstrated on the model of an industrial-scale air separation unit. © 2016 American Institute of Chemical Engineers AIChE J, 63: 639–651, 2017
      PubDate: 2016-07-22T08:55:40.256146-05:
      DOI: 10.1002/aic.15408
       
  • Operational strategy and planning for raw natural gas refining complexes:
           Process modeling and global optimization
    • Authors: Bing J. Zhang; Qing L. Chen, Jie Li, Christodoulos A. Floudas
      Pages: 652 - 668
      Abstract: Optimal operational strategy and planning of a raw natural gas refining complex (RNGRC) is very challenging since it involves highly nonlinear processes, complex thermodynamics, blending, and utility systems. In this article, we first propose a superstructure integrating a utility system for the RNGRC, involving multiple gas feedstocks, and different product specifications. Then, we develop a large-scale nonconvex mixed-integer nonlinear programming (MINLP) optimization model. The model incorporates rigorous process models for input and output relations based on fundamentals of thermodynamics and unit operations and accurate models for utility systems. To reduce the noncovex items in the proposed MINLP model, equivalent reformulation techniques are introduced. Finally, the reformulated nonconvex MINLP model is solved to global optimality using state of the art deterministic global optimization approaches. The computational results demonstrate that a significant profit increase is achieved using the proposed approach compared to that from the real operation. © 2016 American Institute of Chemical Engineers AIChE J, 63: 652–668, 2017
      PubDate: 2016-07-27T09:40:28.609552-05:
      DOI: 10.1002/aic.15416
       
  • Heterogeneous fenton and photo-fenton oxidation for paracetamol removal
           using iron containing ZSM-5 zeolite as catalyst
    • Authors: Filipa Velichkova; Henri Delmas, Carine Julcour, Bogdana Koumanova
      Pages: 669 - 679
      Abstract: Paracetamol is commonly found in wastewaters, as a consequence of its high consumption and incomplete elimination by conventional treatments. Homogenous (photo-)Fenton oxidation has proved efficient for its remediation, but it suffers from uneasy dissolved iron recovery. Therefore this work examines the performance and stability of an iron containing zeolite (Fe/MFI) as catalyst for this reaction. Effects of reaction parameters (pH, temperature, catalyst and H2O2 concentrations, UV/vis irradiation) are investigated in batch conditions, by comparing the pollutant and Total Organic Carbon disappearance rates in solution, as well as the overall mineralization yield (including solid phase) and oxidant consumption. At near neutral pH paracetamol can be fully converted after 5 h, while TOC removal reaches up to 60%. Finally, thanks to good catalyst stability (low leaching), a continuous process coupling oxidation and membrane filtration is proposed, showing constant TOC conversion over 40 h and iron loss in the permeate
      PubDate: 2016-06-28T10:10:27.574216-05:
      DOI: 10.1002/aic.15369
       
  • Hydrophobic mesoporous acidic resin for hydroxyalkylation/alkylation of
           2-methylfuran and ketone to high-density biofuel
    • Authors: Xiangwen Zhang; Qiang Deng, Peijuan Han, Jisheng Xu, Lun Pan, Li Wang, Ji-Jun Zou
      Pages: 680 - 688
      Abstract: Hydroxyalkylation/alkylation of biomass-derived 2-methylfuran with cyclic ketones (cyclopentanone and cyclohexanone) has great potential in synthesizing high-density biofuel. But the conversion and selectivity are still unsatisfactory because the in-situ formed water decreases the acidity of catalyst and induces side reaction. Herein, hydrophobic mesoporous resins with sulfonic acid group (PS) and fluoride sulfonic acid group (PCS) were synthesized by a simple solvothermal reaction and ion exchange treatment, which have good mesoporous structure with surface area of 300–700 m2/g. Notably, PS and PCS have better hydrophobicity and oleophilicity as compared to widely used sulfonic acid functional amberlyst-15 and fluoride sulfonic acid functional nafion-212. In the hydroxyalkylation/alkylation reaction, PS shows higher activity and selectivity than amberlyst-15 while PCS surpasses nafion-212. Furthermore, both PS and PCS have good recycling stability in consecutive 5 runs. After hydrodeoxygenation, two high-density biofuels with density of 0.819 and 0.825 g/mL were obtained. © 2016 American Institute of Chemical Engineers AIChE J, 63: 680–688, 2017
      PubDate: 2016-07-14T09:40:36.388027-05:
      DOI: 10.1002/aic.15410
       
  • Kinetic study of hydrogen peroxide decomposition at high temperatures and
           concentrations in two capillary microreactors
    • Authors: Minjing Shang; Timothy Noël, Yuanhai Su, Volker Hessel
      Pages: 689 - 697
      Abstract: On the background of the direct adipic acid synthesis from cyclohexene and H2O2, a kinetic model was derived for the H2O2 decomposition catalyzed by sodium tungstate at high H2O2 concentrations and high temperatures. A perfluoroalkoxy (PFA) and a stainless steel micro-flow capillary match commonly used microreactor materials. In the PFA capillary, the decomposition of hydrogen peroxide increased with residence time, reaction temperature and catalyst loading. The reaction order with respect to hydrogen peroxide and sodium tungstate was zero and one, respectively. Simulated data fit well with experimental data in the PFA capillary. While showing a similar trend as that in the PFA capillary, the stainless steel capillary exhibited much higher reaction rates. The steel surface participated in the decomposition process as a heterogeneous catalyst. Key influencing factors of the H2O2 decomposition provided some clues on the reaction mechanism of the adipic acid synthesis and its process optimization. © 2016 American Institute of Chemical Engineers AIChE J, 63: 689–697, 2017
      PubDate: 2016-07-19T09:30:44.148379-05:
      DOI: 10.1002/aic.15385
       
  • Catalytic membrane reactor for Suzuki-Miyaura C−C cross-coupling:
           Explanation for its high efficiency via modeling
    • Authors: Yingying Gu; Patrice Bacchin, Jean-François Lahitte, Jean-Christophe Remigy, Isabelle Favier, Montserrat Gómez, Douglas L. Gin, Richard D. Noble
      Pages: 698 - 704
      Abstract: A polymeric catalytic membrane was previously prepared that showed remarkable efficiency for Suzuki-Miyaura C-C cross-coupling in a flow-through configuration. A mathematic model was developed and fitted to the experimental data to understand the significant apparent reaction rate increase exhibited by the catalytic membrane reactor compared to the catalytic system under batch reaction conditions. It appears that the high palladium nanoparticles concentration inside the membrane is mainly responsible for the high apparent reaction rate achieved. In addition, the best performance of the catalytic membrane could be achieved only in the forced flow-through configuration, that, conditions permitting to the reactants be brought to the catalytic membrane by convection. © 2016 American Institute of Chemical Engineers AIChE J, 63: 698–704, 2017
      PubDate: 2016-07-25T09:15:29.616739-05:
      DOI: 10.1002/aic.15379
       
  • An experimental and theoretical study of glycerol oxidation to
           1,3-dihydroxyacetone over bimetallic Pt-Bi catalysts
    • Authors: Yang Xiao; Jeffrey Greeley, Arvind Varma, Zhi-Jian Zhao, Guomin Xiao
      Pages: 705 - 715
      Abstract: It is important to utilize glycerol, the main by-product of biodiesel, to manufacture value-added chemicals such as 1,3-dihydroxyacetone (DHA). In the present work, the performance of five different catalysts (Pt-Bi/AC, Pt-Bi/ZSM-5, Pt/MCM-41, Pt-Bi/MCM-41, and Pt/Bi-doped-MCM-41) was investigated experimentally, where Pt-Bi/MCM-41 was found to exhibit the highest DHA yield. To better understand the experimental results and to obtain insight into the reaction mechanism, density functional theory (DFT) computations were conducted to provide energy barriers of elementary steps. Both experimental and calculated results show that for high DHA selectivity, Bi should be located in an adatom-like configuration Pt, rather than inside Pt. A favorable pathway and catalytic cycle of DHA formation were proposed based on the DFT results. A cooperative effect, between Pt as the primary component and Bi as a promoter, was identified for DHA formation. Both experimental and theoretical considerations demonstrate that Pt-Bi is efficient to convert glycerol to DHA selectively. © 2016 American Institute of Chemical Engineers AIChE J, 63: 705–715, 2017
      PubDate: 2016-07-25T09:35:27.316587-05:
      DOI: 10.1002/aic.15418
       
  • Modeling study for the effect of particle size on char gasification with
           CO2
    • Authors: Zhongjie Shen; Jianliang Xu, Haifeng Liu, Qinfeng Liang
      Pages: 716 - 724
      Abstract: A high temperature stage microscope to investigate the temperature effect caused by particle size on char gasification is applied in this study. Experiments were carried out with different particle sizes for raw chars and chars on molten slag surface, respectively. Heat transfer models were built for the raw char of two temperature distributions and char particle on molten slag, respectively. Results showed that reaction layer temperature of raw char decreased in the reaction dominant while char on molten slag had higher temperature. Temperature difference between two distributions increased with the initial particle size, indicating the temperature effect on large particles was obvious. Shrinking core model was applied and modified herein coupled with the modification of reaction layer temperature and reaction area. Model prediction and experimental data showed good agreements of carbon conversion and reactivity index for raw char and char on molten slag, respectively. © 2016 American Institute of Chemical Engineers AIChE J, 63: 716–724, 2017
      PubDate: 2016-07-27T08:25:50.378724-05:
      DOI: 10.1002/aic.15417
       
  • Amphiphilic poly(ether sulfone) membranes for oil/water separation: Effect
           of sequence structure of the modifier
    • Authors: Guangfa Zhang; Jingxian Jiang, Qinghua Zhang, Xiaoli Zhan, Fengqiu Chen
      Pages: 739 - 750
      Abstract: Oil-contaminated wastewater threatens our environment and health thus novel membrane materials with low or nonfouling properties are an immediate need for oily wastewater treatment in a cost-effective and environmentally friendly manner. In this study, three types of amphiphilic random, gradient, and block copolymers with similar molecular weights and chemical compositions, based on poly(ethylene glycol) methyl ether methacrylate (PEGMA) and 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl acrylate (TFOA), were synthesized by the reversible addition-fragmentation chain transfer (RAFT) method. The amphiphilic Poly(ether sulfone) membranes were then fabricated by blending with these copolymers via a facile coupled process of nonsolvent induced phase separation and surface segregation. Accompanying the phase inversion process of polymer matrix, the hydrophilic and hydrophobic segments in the amphiphilic modifiers would migrate and immobilize onto the membrane surfaces. This surface segregation process leaded to a chemical heterogeneous membrane surface comprising both hydrophilic PEGMA and low surface energy PTFOA brushes, which was confirmed by X-ray photoelectron spectroscopy (XPS) and surface wettability analyses. Oil-in-water emulsion filtration test of the membranes displayed a lower permeate flux decline and a higher flux recovery (as high as 99.8%), establishing their considerably elevated antifouling properties. Additionally, cyclic oil/water separation and long-term underwater immersion tests demonstrated that the as-prepared membranes modified by these amphiphilic additives possessed excellent antifouling stabilities. © 2016 American Institute of Chemical Engineers AIChE J, 63: 739–750, 2017
      PubDate: 2016-06-28T10:15:30.877754-05:
      DOI: 10.1002/aic.15365
       
  • Tuning carbon molecular sieves for natural gas separations: A diamine
           molecular approach
    • Authors: Graham B. Wenz; William J. Koros
      Pages: 751 - 760
      Abstract: This article introduces a new postsynthetic modification method for tuning the separation properties of carbon molecular sieve (CMS) membranes. Polymeric hollow fibers of 6FDA/BPDA-DAM were pyrolyzed to 550°C under inert Argon, and were then exposed to a tetrahydrofuran solution containing PPM levels of paraphenylenediamine dopant. The original goal of the treatment was to modify the morphology in a manner to prevent relaxation of the CMS to suppress physical aging, envisioned to be analogous to that in glassy polymer membranes where reduction of “unrelaxed free volume” causes reduced permeance with a mild increase in selectivity. Results of long-term CO2 and CH4 permeation experiments of doped fibers showed that aging-resistant membranes did not result. This fact notwithstanding, results revealed this approach provides a valuable new tuning tool for CMS transport properties. Complementary gas sorption experiments performed suggest the amine dopants tune large ultramicropores, thereby increasing size and shape based diffusion selectivity. © 2016 American Institute of Chemical Engineers AIChE J, 63: 751–760, 2017
      PubDate: 2016-07-22T08:35:57.13951-05:0
      DOI: 10.1002/aic.15405
       
  • Krypton-xenon separation properties of SAPO-34 zeolite materials and
           membranes
    • Authors: Yeon Hye Kwon; Christine Kiang, Emily Benjamin, Phillip Crawford, Sankar Nair, Ramesh Bhave
      Pages: 761 - 769
      Abstract: Separation of the radioisotope 85Kr from 136Xe is an important target during used nuclear fuel recycling. We report a detailed study on the Kr and Xe adsorption, diffusion, and membrane permeation properties of the silicoaluminophosphate zeolite SAPO-34. Adsorption and diffusion measurements on SAPO-34 crystals indicate their potential for use in Kr-Xe separation membranes, but also highlight competing effects of adsorption and diffusion selectivity. SAPO-34 membranes are synthesized on α−alumina disk and tubular substrates via steam assisted conversion seeding and hydrothermal growth, and are characterized in detail. Membrane transport measurements reveal that SAPO-34 membranes can separate Kr from Xe by molecular sieving, with Kr permeabilities around 50 Barrer and mixture selectivity of 25–30 for Kr at ambient or slight sub-ambient conditions. The membrane transport characteristics are modeled by the Maxwell-Stefan equations, whose predictions are in very good agreement with experiment and confirm the minimal competing effects of adsorption and diffusion. © 2016 American Institute of Chemical Engineers AIChE J, 63: 761–769, 2017
      PubDate: 2016-07-27T10:05:23.157747-05:
      DOI: 10.1002/aic.15434
       
  • Influence of ionic liquid composition on the stability of polyvinyl
           chloride-based ionic liquid inclusion membranes in aqueous solution
    • Authors: Francisca Tomás-Alonso; Aurora M. Rubio, Alfonso Giménez, Antonia P. de los Ríos, Maria J. Salar-García, Victor M. Ortiz-Martínez, Francisco J. Hernández-Fernández
      Pages: 770 - 780
      Abstract: Membrane technology has gained significant importance with the incorporation of ionic liquids into their structure. This work shows the influence of ionic liquid composition on the stability of PVC-based polymer ionic liquid inclusion membranes (PILIMs) in aqueous solution. Among the ILs investigated, those membranes which contain between 20 and 30%w/w of the least soluble, [OMIM+][PF6−] and [OMIM+][Ntf2−], exhibit losses of IL lower than 10%. For both ILs, the amount immobilized was maximum for the membranes with 30%w/w of IL (0.0838 and 0.0832 g, respectively). On the contrary, the ionic liquid loss increases as its solubility in water increase, reaching 99.52% when PILIMs are prepared with 70%w/w of [OMIM+][BF4−]. The results demonstrate that the stability of PILIMs depends on the solubility of the IL in the surrounding phase and the specific interaction between the IL and the polymeric support for PVC-to-IL ratios higher than 30%w/w. © 2016 American Institute of Chemical Engineers AIChE J, 63: 770–780, 2017
      PubDate: 2016-09-06T10:20:33.422706-05:
      DOI: 10.1002/aic.15460
       
  • Computing MOSCED parameters of nonelectrolyte solids with electronic
           structure methods in SMD and SM8 continuum solvents
    • Authors: Jeremy R. Phifer; Kimberly J. Solomon, Kayla L. Young, Andrew S. Paluch
      Pages: 781 - 791
      Abstract: An efficient method to predict modified separation of cohesive energy density model (MOSCED) parameters for nonelectrolyte solids using electronic structure calculations in SMD and SM8 continuum solvents is proposed and applied to acetanilide, acetaminophen, and phenacetin. The resulting parameters are ultimately used to predict the equilibrium solubility in a range of solvents over a range of temperatures. By combining MOSCED with SMD and SM8, we are able to leverage the strengths of both methods while eliminating shortcomings that would prevent their use alone for solvent selection in design processes involving nonelectrolyte solid solutes. Comparing to 77 non-aqueous experimental solubilities of acetaminophen over the range 10–30°C, the proposed method has an average absolute error of 0.03 and 0.04 mol fracs for SMD and SM8 regressed parameters, respectively. Aqueous solubilities of acetaminophen over this temperature range are predicted with an average error of 0.030 and 0.0023 mol fracs, respectively. © 2016 American Institute of Chemical Engineers AIChE J, 63: 781–791, 2017
      PubDate: 2016-07-26T09:45:34.681458-05:
      DOI: 10.1002/aic.15413
       
  • Flow pattern transition in gas-liquid downflow through narrow vertical
           tubes
    • Authors: Amit Kumar; Satyabrata Bhowmik, Subhabrata Ray, Gargi Das
      Pages: 792 - 800
      Abstract: The present report studies on the flow pattern transitions during vertical air water downflow through millichannels (0.83 ≤ Eötvös no. ≤ 20.63). Four basic flow patterns namely falling film flow, slug flow, bubbly flow, and annular flow are observed in the range of experimental conditions studied and their range of existence has been noted to vary with tube diameter and phase velocities. Based on experimental observations, phenomenological models are proposed to predict the transition boundaries between adjacent patterns. These have been validated with experimental flow pattern maps from the present experiments. Thus the study formalizes procedure for developing a generalized flow pattern map for gas-liquid downflow in narrow tubes. © 2016 American Institute of Chemical Engineers AIChE J, 63: 792–800, 2017
      PubDate: 2016-06-28T10:10:24.875423-05:
      DOI: 10.1002/aic.15364
       
  • A study on hydrodynamic characteristics in a Φ38 pulsed extraction column
           by four-sensor optical fiber probe
    • Authors: Yukun Yuan; Yang Gao
      Pages: 801 - 811
      Abstract: Accurate prediction of dispersed phase droplet behavior is crucial to the design and scaling-up of an extraction column. In this article, the dispersed droplet velocity algorithm and the diameter algorithm in a liquid–liquid two-phase flow have been developed based on the bubble velocity model in gas–liquid two-phase flow of Lucas [Measurement Science & Technology. 749, 758(2005)] and Shen [International Journal of Multiphase Flow. 593, 617(2005)]. Hydrodynamic characteristics, including droplet diameter, holdup and droplet velocity, were measured using a self-made four-sensor optical fiber probe in a 38 mm-diameter pulsed sieve-plate extraction column. Water and kerosene were used as continuous and dispersed phases, respectively. The influences of the pulsed intensity, the continuous and dispersed phase superficial velocities on the hydrodynamic characteristics were investigated. The experimental results show that it is reliable to use a four-sensor optical probe to measure the hydrodynamic characteristics of a pulsed extraction column. © 2016 American Institute of Chemical Engineers AIChE J, 63: 801–811, 2017
      PubDate: 2016-07-01T09:55:47.507169-05:
      DOI: 10.1002/aic.15328
       
  • Experimentally-based constitutive relations for co-current gas-liquid flow
           in randomly packed beds
    • Authors: Paul Salgi; Vemuri Balakotaiah
      Pages: 812 - 822
      Abstract: Experimental Observations on average pulse velocity and frequency in concurrent gas-liquid (down) flow through randomly packed beds are used to extract constitutive relations for the gas-liquid interaction and mean curvature terms that appear in a recently proposed volume-averaged two-fluid model for bubbly flow. The proposed closures lead to a reasonably quantitative prediction of the average pressure drop and liquid saturation under bubbly flow conditions and in the near pulse regime. In addition, the proposed closures provide realistic estimates for the location of the bubble-to-pulse transition in microgravity and in 1g down-flow and predict the disappearance of the bubbly flow pattern at low liquid fluxes in 1g down-flow. © 2016 American Institute of Chemical Engineers AIChE J, 63: 812–822, 2017
      PubDate: 2016-07-11T09:40:32.956248-05:
      DOI: 10.1002/aic.15377
       
  • Quantitative evaluation of mass transfer near the edge of porous media by
           absorption photometry
    • Authors: Taiki Tanikoshi; Ryoko Otomo, Shusaku Harada
      Pages: 823 - 833
      Abstract: The intensive investigation of mass transfer near the entrance (edge) of porous media by quantification of the surrounding concentration field has been performed. We have adopted a noninvasive and real-time system based on light absorption photometry for measurement of the concentration field in a quasi-two dimensional cell. This system is, in principle, applicable to the measurement of various substances due to the generality of light absorption. This measurement system was applied to a simple model of the gravity-driven transport of a substance in a fluid near the edge of a porous medium in the presence of a reaction at the surface. The temporal variation of the complicated concentration field is appropriately captured with a spatial resolution of several tens of micrometers to millimeters. Quantitative analyses revealed that the geometry of the porous edge considerably affects the convection flow and invasion of substances into the medium. © 2016 American Institute of Chemical Engineers AIChE J, 63: 823–833, 2017
      PubDate: 2016-07-14T09:50:41.302898-05:
      DOI: 10.1002/aic.15397
       
  • Fluid inhomogeneity within nanoslits and deviation from
           Hagen–Poiseuille flow
    • Authors: Yuying Wang; Junbo Xu, Chao Yang
      Pages: 834 - 842
      Abstract: Recently, the deviation of nano-confined flows from classical hydrodynamic theories has been frequently reported. In this work, such a flow is theoretically investigated by means of dissipative particle dynamics (DPD) simulation. The simulation results show that the density and viscosity inhomogeneities near solid/fluid interfaces depends on the slit wettability only. Flow enhancement relative to the Hagen–Poiseuille (H-P) flow occurs together with the flow inhomogeneity. Combining of flow inhomogeneity and the Stokes equation, a theoretical model for flux calculation is established. As the slit being widened, the model can be simplified by gradually eliminating the higher order traces, and be simplified into the model with Navier's slip condition and the well-known H-P relation at last. The theoretical results of flux are in good agreement with the simulations by DPD. © 2016 American Institute of Chemical Engineers AIChE J, 63: 834–842, 2017
      PubDate: 2016-07-22T08:31:02.35105-05:0
      DOI: 10.1002/aic.15409
       
  • Power consumption and form drag of regular and fractal-shaped turbines in
           a stirred tank
    • Authors: K. Steiros; P. J. K. Bruce, O. R. H. Buxton, J. C. Vassilicos
      Pages: 843 - 854
      Abstract: Previous wind-tunnel measurements have shown that fractal-shaped plates have increased drag compared to square plates of the same area. In this study, the power consumption and drag of turbines with fractal and rectangular blades in a stirred tank are measured. Power number decreases from rectangular to fractal impellers by over 10%, increasingly so with fractal iteration number. Our results suggest that this decrease is not caused by the wake interaction of the blades, nor solely by the wake interaction with the walls either. Pressure measurements on the blades’ surface show that fractal blades have lower drag than the rectangular ones, opposite to the wind tunnel experiment results. All tested blades’ center of pressure radius increases with Re, while their drag coefficient decreases, a possible effect of the solid body rotation expansion with Re. Spectral analysis of the pressure signal reveals two peaks possibly connected to the blades’ roll vortices. © 2016 American Institute of Chemical Engineers AIChE J, 63: 843–854, 2017
      PubDate: 2016-07-27T10:38:04.620679-05:
      DOI: 10.1002/aic.15414
       
 
 
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