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  Subjects -> ENGINEERING (Total: 2255 journals)
    - CHEMICAL ENGINEERING (187 journals)
    - CIVIL ENGINEERING (178 journals)
    - ELECTRICAL ENGINEERING (99 journals)
    - ENGINEERING (1203 journals)
    - ENGINEERING MECHANICS AND MATERIALS (383 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (60 journals)
    - MECHANICAL ENGINEERING (90 journals)

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

Showing 201 - 400 of 1205 Journals sorted alphabetically
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Current Science     Open Access   (Followers: 12)
Dams and Reservoirs     Hybrid Journal   (Followers: 3)
Data Handling in Science and Technology     Full-text available via subscription   (Followers: 4)
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 25)
Designed Monomers and Polymers     Hybrid Journal  
Designs, Codes and Cryptography     Hybrid Journal   (Followers: 6)
Development Engineering     Open Access  
Developments in Clay Science     Full-text available via subscription  
Developments in Geotechnical Engineering     Full-text available via subscription   (Followers: 3)
Developments in Mineral Processing     Full-text available via subscription   (Followers: 2)
Diálogos Interdisciplinares     Open Access  
Diamond Light Source Proceedings     Full-text available via subscription  
Diffusion Foundations     Full-text available via subscription  
Digital Signal Processing     Hybrid Journal   (Followers: 11)
Discrete Optimization     Full-text available via subscription   (Followers: 4)
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: 2)
Electrophoresis     Hybrid Journal   (Followers: 20)
Elementos     Open Access  
Elsevier Geo-Engineering Book Series     Full-text available via subscription   (Followers: 2)
Elsevier Ocean Engineering Series     Full-text available via subscription  
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 30)
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations     Open Access  
Energies     Open Access   (Followers: 3)
Energy and Power Engineering     Open Access   (Followers: 15)
Energy Conversion and Management     Hybrid Journal   (Followers: 7)
Energy Engineering     Full-text available via subscription   (Followers: 9)
Energy for Sustainable Development     Hybrid Journal   (Followers: 8)
Energy Procedia     Open Access   (Followers: 2)
Energy Science & Engineering     Open Access   (Followers: 3)
Energy Science and Technology     Open Access   (Followers: 13)
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: 21)
Engineering : The official journal of the Chinese Academy of Engineering and Higher Education Press     Open Access   (Followers: 1)
Engineering Analysis with Boundary Elements     Hybrid Journal   (Followers: 1)
Engineering Computations     Hybrid Journal   (Followers: 3)
Engineering Economics     Open Access   (Followers: 4)
Engineering Economist, The     Hybrid Journal   (Followers: 4)
Engineering Failure Analysis     Hybrid Journal   (Followers: 63)
Engineering Geology     Hybrid Journal   (Followers: 6)
Engineering International     Open Access  
Engineering Journal     Open Access   (Followers: 1)
Engineering Management Journal     Hybrid Journal   (Followers: 18)
Engineering Management Research     Open Access   (Followers: 5)
Engineering Management Reviews     Open Access   (Followers: 1)
Engineering Optimization     Hybrid Journal   (Followers: 6)
Engineering Science and Technology, an International Journal     Open Access  
Engineering Sciences     Open Access  
Engineering Studies     Hybrid Journal  
Engineering With Computers     Hybrid Journal   (Followers: 6)
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: 13)
ESAIM: Control Optimisation and Calculus of Variations     Full-text available via subscription  
ESAIM: Mathematical Modelling and Numerical Analysis     Full-text available via subscription   (Followers: 4)
ESAIM: Proceedings     Open Access  
Estuaries and Coasts     Hybrid Journal   (Followers: 16)
European Journal of Combinatorics     Full-text available via subscription   (Followers: 3)
European Journal of Engineering Education     Hybrid Journal   (Followers: 3)
European Journal of Lipid Science and Technology     Hybrid Journal   (Followers: 1)
European Journal of Mass Spectrometry     Full-text available via subscription   (Followers: 17)
European Medical Device Technology     Full-text available via subscription   (Followers: 3)
European Physical Journal - Applied Physics     Full-text available via subscription   (Followers: 7)
European Transport Research Review     Open Access   (Followers: 21)
Evolutionary Intelligence     Hybrid Journal  
Evolving Systems     Hybrid Journal  
Exacta     Open Access  
Experimental Techniques     Hybrid Journal   (Followers: 55)
Experiments in Fluids     Hybrid Journal   (Followers: 7)
Fibers and Polymers     Full-text available via subscription   (Followers: 4)
Filtration & Separation     Full-text available via subscription   (Followers: 4)
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 4)
Fire Science Reviews     Open Access   (Followers: 5)
Flexible Services and Manufacturing Journal     Hybrid Journal   (Followers: 1)
Flow, Turbulence and Combustion     Hybrid Journal   (Followers: 21)
Fluid Dynamics     Hybrid Journal   (Followers: 7)
Fluid Dynamics Research     Full-text available via subscription   (Followers: 9)
Fluid Phase Equilibria     Hybrid Journal   (Followers: 4)
Focus on Catalysts     Full-text available via subscription  
Focus on Pigments     Full-text available via subscription   (Followers: 3)
Focus on Powder Coatings     Full-text available via subscription   (Followers: 3)
Focus on Surfactants     Full-text available via subscription   (Followers: 3)
Food Engineering Reviews     Hybrid Journal   (Followers: 3)
Food Science and Technology     Open Access   (Followers: 3)
Formación Universitaria     Open Access   (Followers: 3)
FORMakademisk     Open Access  
Formal Methods in System Design     Hybrid Journal   (Followers: 7)
Forschung     Hybrid Journal  
Forschung im Ingenieurwesen     Hybrid Journal   (Followers: 1)
Foundations of Science     Hybrid Journal  
Frontiers in Aerospace Engineering     Open Access   (Followers: 7)
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: 4)
Fuel Cells     Hybrid Journal   (Followers: 3)
Fuel Cells Bulletin     Full-text available via subscription   (Followers: 4)
Fusion Engineering and Design     Hybrid Journal   (Followers: 8)
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: 6)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 29)
Geotechnical Testing Journal     Full-text available via subscription   (Followers: 8)
Géotechnique     Hybrid Journal   (Followers: 11)
Geothermics     Hybrid Journal   (Followers: 4)
Glass Technology - European Journal of Glass Science and Technology Part A     Full-text available via subscription   (Followers: 3)
Global Journal of Engineering Research     Full-text available via subscription  
Global Perspective on Engineering Management     Open Access   (Followers: 1)
GPS Solutions     Hybrid Journal   (Followers: 13)
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: 7)
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: 2)
Heat Exchangers     Open Access   (Followers: 1)
Heat Transfer - Asian Research     Hybrid Journal   (Followers: 7)
Heat Transfer Engineering     Hybrid Journal   (Followers: 22)
Historical Records of Australian Science     Hybrid Journal   (Followers: 2)
Human Factors in Ergonomics & Manufacturing     Hybrid Journal   (Followers: 5)
Iberoamerican Journal of Project Management     Open Access   (Followers: 3)
IBM Journal of Research and Development     Hybrid Journal   (Followers: 17)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 32)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 27)
IEEE Communications Magazine     Full-text available via subscription   (Followers: 43)
IEEE Control Systems Magazine     Full-text available via subscription   (Followers: 52)
IEEE Engineering Management Review     Full-text available via subscription   (Followers: 28)
IEEE Geoscience and Remote Sensing Letters     Hybrid Journal   (Followers: 29)
IEEE Industry Applications Magazine     Full-text available via subscription   (Followers: 16)
IEEE Instrumentation & Measurement Magazine     Full-text available via subscription   (Followers: 44)
IEEE Journal of Biomedical and Health Informatics     Hybrid Journal   (Followers: 11)
IEEE Journal of Oceanic Engineering     Hybrid Journal   (Followers: 10)
IEEE Journal of Selected Topics in Quantum Electronics     Hybrid Journal   (Followers: 8)
IEEE Journal of Selected Topics in Signal Processing     Hybrid Journal   (Followers: 24)
IEEE Journal of Solid-State Circuits     Full-text available via subscription   (Followers: 18)
IEEE Journal on Selected Areas in Communications     Hybrid Journal   (Followers: 12)
IEEE Latin America Transactions     Full-text available via subscription   (Followers: 2)
IEEE Microwave and Wireless Components Letters     Hybrid Journal   (Followers: 13)
IEEE Microwave Magazine     Full-text available via subscription   (Followers: 22)
IEEE Potentials     Full-text available via subscription   (Followers: 17)
IEEE Signal Processing Letters     Hybrid Journal   (Followers: 27)
IEEE Spectrum     Full-text available via subscription   (Followers: 115)
IEEE Technology and Society Magazine     Full-text available via subscription   (Followers: 2)
IEEE Transactions on Advanced Packaging     Full-text available via subscription   (Followers: 7)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 24)
IEEE Transactions on Applied Superconductivity     Hybrid Journal   (Followers: 3)
IEEE Transactions on Automation Science and Engineering     Full-text available via subscription   (Followers: 9)
IEEE Transactions on Circuits and Systems II: Express Briefs     Hybrid Journal   (Followers: 12)
IEEE Transactions on Components and Packaging Technologies     Full-text available via subscription   (Followers: 14)
IEEE Transactions on Control Systems Technology     Hybrid Journal   (Followers: 39)
IEEE Transactions on Education     Hybrid Journal   (Followers: 6)
IEEE Transactions on Electronics Packaging Manufacturing     Full-text available via subscription   (Followers: 16)
IEEE Transactions on Energy Conversion     Hybrid Journal   (Followers: 9)
IEEE Transactions on Engineering Management     Hybrid Journal   (Followers: 20)
IEEE Transactions on Evolutionary Computation     Hybrid Journal   (Followers: 8)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 15)
IEEE Transactions on Instrumentation and Measurement     Hybrid Journal   (Followers: 39)
IEEE Transactions on Intelligent Transportation Systems     Hybrid Journal   (Followers: 6)
IEEE Transactions on Knowledge and Data Engineering     Hybrid Journal   (Followers: 22)
IEEE Transactions on Magnetics     Hybrid Journal   (Followers: 9)
IEEE Transactions on Microwave Theory and Techniques     Hybrid Journal   (Followers: 17)
IEEE Transactions on Nuclear Science     Hybrid Journal   (Followers: 7)
IEEE Transactions on Plasma Science     Hybrid Journal   (Followers: 7)
IEEE Transactions on Power Delivery     Hybrid Journal   (Followers: 16)
IEEE Transactions on Professional Communication     Hybrid Journal   (Followers: 4)
IEEE Transactions on Reliability     Hybrid Journal   (Followers: 26)
IEEE Transactions on Semiconductor Manufacturing     Hybrid Journal   (Followers: 5)
IEEE Transactions on Signal Processing     Hybrid Journal   (Followers: 49)
IEEE Transactions on Vehicular Technology     Hybrid Journal   (Followers: 2)
IEEE Vehicular Technology Magazine     Full-text available via subscription   (Followers: 8)
IEEE/ACM Transactions on Computational Biology and Bioinformatics     Hybrid Journal   (Followers: 14)
IERI Procedia     Open Access  
IET Circuits, Devices & Systems     Hybrid Journal   (Followers: 17)
IET Generation, Transmission & Distribution     Hybrid Journal   (Followers: 2)
IET Image Processing     Hybrid Journal   (Followers: 13)
IET Micro and Nano Letters     Hybrid Journal   (Followers: 6)
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 9)
IET Optoelectronics     Hybrid Journal   (Followers: 1)

  First | 1 2 3 4 5 6 7 | Last

Journal Cover AIChE Journal
  [SJR: 1.098]   [H-I: 104]   [27 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0001-1541 - ISSN (Online) 1547-5905
   Published by John Wiley and Sons Homepage  [1598 journals]
  • Cohesive grains: Bridging micro‐level measurements to
           macro‐level flow behavior via surface roughness
    • Authors: Peiyuan Liu; Casey Q. LaMarche, Kevin M. Kellogg, Stuart Leadley, Christine M. Hrenya
      Abstract: Understanding fine‐particle flows relies on van der Waals cohesion modeling, requiring a method to consider measured surface roughness. We propose a robust scheme to extract roughness parameters from AFM surface maps, achieving accurate predictions of micro‐scale measured cohesion. Macro‐scale quantitative agreement is demonstrated by comparing defluidization predictions to measurements, which are sensitive to cohesion and system‐size independent. Agreement in both micro‐ and macro‐scale comparisons highlights the role of individual particle properties on bulk granular systems. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-18T10:21:02.002845-05:
      DOI: 10.1002/aic.15383
       
  • Kinetic study of hydrogen peroxide decomposition at high temperatures and
           concentrations in two capillary microreactors
    • 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. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-18T10:20:41.93671-05:0
      DOI: 10.1002/aic.15385
       
  • Metal‐Organic Frameworks for Highly Efficient Adsorption of
           Dibenzothiophene from Liquid Fuels
    • Authors: Weijia Tang; Jianlei Gu, Hongliang Huang, Dahuan Liu, Chongli Zhong
      Abstract: By taking desulfurization of liquid fuels as a demonstrative example, a bottom‐up selection was performed to find the MOF‐type adsorbents with highly efficient adsorption performance of large molecules. Through carefully analyzing the adsorption mechanism for typical S‐heterocyclic compounds like dibenzothiophene (DBT), PCN‐10 was selected in consideration of the simultaneous inclusion of several kinds of interactions in the framework. Experimental results demonstrate that this MOF exhibits extraordinary high DBT adsorption capacity (75.24 mg S g−1), showing record uptake among all the reported porous materials for the removal of thiophenicsulfur from fuels (below 1000 ppmwS), to the best of our knowledge. Moreover, the removal rate for the low sulfur concentration (50 ppmwS) can reach beyond 99%. This strategy can be conveniently extended to the screening and design of MOFs for the efficient removal of other important large guest molecules. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-18T10:20:24.565114-05:
      DOI: 10.1002/aic.15384
       
  • Uncertainty quantification via Bayesian inference using Sequential Monte
           Carlo methods for CO2 adsorption process
    • Authors: Jayashree Kalyanaraman; Yoshiaki Kawajiri, Ryan P. Lively, Matthew J. Realff
      Abstract: This work presents the uncertainty quantification, which includes parametric inference along with uncertainty propagation, for CO2 adsorption in a hollow fiber sorbent, a complex dynamic chemical process. Parametric inference via Bayesian approach is performed using sequential Monte Carlo, a completely parallel algorithm, and the predictions are obtained by propagating the posterior distribution through the model. The presence of residual variability in the observed data and model inadequacy often present a significant challenge in performing the parametric inference. In this work, residual variability in the observed data is handled by three different approaches: (a) by performing inference with isolated data sets, (b) by increasing the uncertainty in model parameters, and finally, (c) by using a model discrepancy term to account for the uncertainty. The pros and cons of each of the three approaches are illustrated along with the predicted distributions of CO2 breakthrough capacity for a scaled‐up process. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-18T10:15:33.377806-05:
      DOI: 10.1002/aic.15381
       
  • Revealing the role of bromide in the H2O2 direct synthesis with the
           Catalyst Wet Pretreatment Method (CWPM)
    • Abstract: A tailor‐made Pd0/K2621 catalyst was subjected to post synthesis modification via a wet treatment procedure. The aim was the understanding of the role of promoters and how ‐ if any ‐ improvements could be qualitatively related to the catalyst performance for the H2O2 direct synthesis. The Catalyst Wet Pretreatment Method (CWPM) was applied in different methanolic solutions containing H2O2, NaBr and H3PO4, either as single modifiers or as a mixture. The catalyst was characterized by Transmission Electron Microscopy (TEM) and X‐ray Photoelectron Spectroscopy (XPS). It was concluded that the modified catalysts give rise to higher selectivities compared to the pristine reference catalyst thus opening a possibility to exclude the addition of the undesirable selectivity enhancers in the reaction medium. This work provides original evidence on the role of promoters, especially bromide, allowing the formulation of a new reaction mechanism for one of the most challenging reactions recognized by the world. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-18T10:15:27.038814-05:
      DOI: 10.1002/aic.15382
       
  • Physical Mixtures as Simple and Efficient Alternative to Alloy Carriers in
           Chemical Looping Processes
    • Abstract: Chemical Looping Combustion is a clean combustion technology for fossil or renewable fuels. We have previously demonstrated application of chemical looping to CO2 activation via reduction to CO with concurrent production of synthesis gas (CO+ H2) from CH4 via rationally designed Fe‐Ni alloys. Here, we demonstrate that that a simple physical mixture can even outperform the equivalent alloy based on an intricate gas phase mediated coupling between the two metals: Ni cracks methane to carbon and H2. The latter then reduces iron oxide carrier, forming steam, which gasifies the carbon deposits on Ni to produce a mixture of CO + H2, thus regenerating the active Ni surface. We suggest that the principle demonstrated here—the gas phase‐mediated coupling of two solid reactants with distinct functionalities—should be applicable broadly towards oxidation reactions and hence opens a new avenue for rational design of chemical looping processes. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-18T10:10:25.445974-05:
      DOI: 10.1002/aic.15380
       
  • Catalytic membrane reactor for Suzuki‐Miyaura C‐C
           cross‐coupling: Explanation for its high efficiency via modeling
    • 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. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-17T06:55:29.011669-05:
      DOI: 10.1002/aic.15379
       
  • Experimentally‐Based Constitutive Relations for Co‐Current
           Gas‐Liquid Flow in Randomly Packed Beds
    • Authors: Paul Salgi; Vemuri Balakotaiah
      Abstract: We use experimental observations on average pulse velocity and frequency in concurrent gas‐liquid (down) flow through randomly packed beds 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. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-16T19:50:55.855697-05:
      DOI: 10.1002/aic.15377
       
  • Nonsmooth Model for Dynamic Simulation of Phase Changes
    • Authors: Ali M. Sahlodin; Harry A. J. Watson, Paul I. Barton
      Abstract: Dynamic modeling of processes involving phase changes can be challenging due to changes in the model equations caused by appearance and disappearance of equilibrium phases. Dynamic simulation of these processes requires the ability to detect the change in the number of phases and adapt the model to the new phase regime on the fly. In this work, an easy‐to‐use nonsmooth model for dynamic simulation of processes with vapor‐liquid equilibrium is presented. The presented model does not introduce any auxiliary variables or equations, nor does it require solution of an optimization problem to determine the new phase regime during the dynamic simulation. It can therefore be used for comprehensive simulation of, e.g., distillation columns, where the number of phases present can change during startup and shutdown. The nonsmooth model is illustrated through examples of an evaporator and a distillation column. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-16T19:50:52.107117-05:
      DOI: 10.1002/aic.15378
       
  • Computational Study of Core‐shell Droplet Formation in Coaxial
           Electrohydrodynamic Atomization Process
    • Abstract: In this study, a computational fluid dynamic (CFD) model was developed to simulate the liquid cone‐jet and core‐shell droplet formation in the Coaxial Electrohydrodynamic Atomization (CEHDA) process. Validation experiments were conducted using poly(lactic acid) (PLA) and poly(lactic‐co‐glycolic acid) (PLGA) solutions as core and shell materials, respectively. Good agreement was obtained between experimental results and simulation predictions in terms of both particle size and core‐shell structure. Investigation of interfacial tension between core and shell fluids showed that a stable compound cone‐jet and droplet can be easily formed using miscible or partially miscible liquids compared with immiscible liquids with higher interfacial tension. It was also found that the nozzle tip configuration has significant effects on droplet production due to differences in fluid motion. The results also showed that the productivity of the CEHDA process, i.e. slow production of core‐shell microparticles due to low flow rates, could be enhanced by using optimal cone‐shaped nozzle configuration. Overall, this computational model provided a means of designing and optimizing CEHDA processes for large‐scale core‐shell microparticle fabrication in pharmaceutical application, such as selections of materials and nozzle configuration. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T08:50:59.946622-05:
      DOI: 10.1002/aic.15361
       
  • A generalized stochastic modelling approach for crystal size distribution
           in antisolvent crystallization operations
    • Authors: Roberto Baratti; Stefania Tronci, Jose A. Romagnoli
      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. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T03:40:49.461204-05:
      DOI: 10.1002/aic.15372
       
  • Erratum to “An Integrated Framework for Scheduling and Control Using
           Fast Model Predictive Control”
    • Authors: Lisia S. Dias; Jinjun Zhuge, Marianthi G. Ierapetritou
      PubDate: 2016-06-15T03:40:48.164693-05:
      DOI: 10.1002/aic.15375
       
  • 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
      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. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T03:40:45.875901-05:
      DOI: 10.1002/aic.15374
       
  • Macro‐Economic Multi‐Objective Input‐Output Model for
           Minimizing CO2 Emissions: Application to the U.S. Economy
    • Abstract: Designing effective environmental policies for mitigating global warming is a very challenging task that requires detailed knowledge of the international channels through which goods are traded. This work presents a decision‐support tool that minimizes the impact at a global macroeconomic scale by performing changes in the economic sectors of an economy. Our tool combines multi‐objective optimization, environmentally extended input‐output tables and life cycle assessment within a unified framework. Our results on the US economy to minimize CO2 emissions identify sectors that should be regulated first to reach a given environmental target while maximizing the demand satisfaction. The impact of shale gas is also studied. Our findings show that the application of process systems engineering tools at a macroeconomic level can provide valuable insight for public policy makers into problems of general interest. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T03:40:40.611982-05:
      DOI: 10.1002/aic.15376
       
  • Polynomial chaos‐based robust design of systems with probabilistic
           uncertainties
    • Authors: Dongying E. Shen; Richard D. Braatz
      Abstract: A new algorithm is proposed for the design of nonlinear dynamical systems with probabilistic uncertainties. The dependence of the design objective and constraints on uncertainties is quantified by the polynomial chaos expansions (PCEs), while the relationships between the design parameters and the design objective/constraints are parameterized by Legendre polynomials. In two case studies, the polynomial chaos‐based algorithm reduces the number of system evaluations required by optimization by an order of magnitude. Quantifying the dependence on uncertain parameters via the PCEs and including the quantification in design optimization simultaneously improved the distribution of the performance index and the probability of constraint fulfillment. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T03:35:39.014455-05:
      DOI: 10.1002/aic.15373
       
  • A controllability analysis of a pilot‐scale CO2 capture plant using
           ionic liquids
    • Abstract: Nowadays there is a world concern on the impact and effect of large CO2 atmospheric concentrations on human health. Fossil‐fuel combustion processes in power plants are among the major contributors to this issue. Hence, it becomes important to develop new clean and sustainable processes aimed to reduce the amount of CO2 released to atmosphere by combustion processes in power plants. One of the best feasible manners to achieve this purposes lies in the use of a closed‐loop control system able to keep the amount of green‐house gases under specification even in the presence of unexpected scenarios. Of course, CO2 capture has been extensively researched in the past. However, in this regard the industrial practice has consisted in using Amines leading to sustainability and safety issues. Hence, it makes sense to seek for new and potentially environmental friendly process design to address CO2 reduction from power plants but applying a new type of sustainable stripping solvents. In this work we address the sustainable CO2 reduction issue from a process control point of view applying a previous design proposed by our research team based on the deployment of Ionic Liquids as potential green solvents and developing an efficient and decentralized multi‐loop control system. We demonstrate that the closed‐loop system is able to maintain the CO2 concentration levels under specification by testing in presence of several demanding scenarios. Overall, from an economic, sustainable and control point of view it looks feasible to replace the traditional amines‐based CO2 capture process by other alternatives based on the application of ionic liquids as potential green solvents. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T03:35:37.930387-05:
      DOI: 10.1002/aic.15371
       
  • 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
      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 paper 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. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T03:35:29.375466-05:
      DOI: 10.1002/aic.15370
       
  • Study on dynamic behavior adjustment of nonlinear chemical processes
    • Authors: Hao Jiang; Bingzhen Chen
      Abstract: In nonlinear chemical processes, many economically desirable operating conditions are located in unstable regions, leading to product quality degradation and safety problems. Therefore, determining how to adjust the dynamic behavior to make the process stable within its desired operational range is a topic of common interest within industrial and academic communities. This article presents a dynamic behavior adjustment method based on a washout filter‐aided controller with an improved parameter‐tuning algorithm to stabilize parts of the equilibrium manifold of chemical processes. In addition, applying this method to industrial toluene liquid‐phase catalytic oxidation shows that, by combining a conventional proportional‐integral (PI) controller with the proposed improved washout filter‐aided controller, the performance of set‐point tracking is improved for cases with parameter uncertainty. In general, the proposed dynamic behavior adjustment method will be effective for most chemical processes. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-13T14:10:29.614353-05:
      DOI: 10.1002/aic.15342
       
  • Inducing arbitrary vapor pressures, and quantifying leakages
    • Authors: Rafael Tadmor; Priyanka S. Wasnik, Hartmann E. N'guessan, Rafael Tadmor, Maria Tadmor
      Abstract: We generalize the Maxwell drop evaporation equation to cover the range from closed system to open system through semiclosed system where the evaporation is restricted to an arbitrary degree which we show how to characterize. We first consider a suspended drop, and then a drop contacting a surface where the surface's vicinity restricts the evaporation paths. We show how to use these results to obtain arbitrary values of vapor pressure by simple manipulations of the numbers and sizes of droplets added to the system for a constant leak size, or, alternatively, control the leak size with a valve for given sizes of drops. We further show how to use this result to quantify a leakage in a system. Such a leakage is characterized using a single parameter (leakage length) which the described method calibrates. The calibrated leakage length can be used for systematic control of vapor concentrations within the chamber. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-13T13:35:29.102356-05:
      DOI: 10.1002/aic.15329
       
  • Control‐relevant decomposition of process networks via
           optimization‐based hierarchical clustering
    • Authors: Seongmin Heo; Prodromos Daoutidis
      Abstract: A systematic method is proposed for control‐relevant decomposition of complex process networks. Specifically, hierarchical clustering methods are adopted to identify constituent subnetworks such that the components of each subnetwork are strongly interacting while different subnetworks are loosely coupled. Optimal clustering is determined through the solution of integer optimization problems. The concept of relative degree is used to measure distance between subnetworks and compactness of subnetworks. The application of the proposed method is illustrated using an example process network. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-13T13:30:34.366581-05:
      DOI: 10.1002/aic.15323
       
  • Novel metal‐organic framework membrane process for high purity CO2
           production
    • Authors: Zebao Rui; Joshua B. James, Alexandra Kasik, Y.S. Lin
      Abstract: Gas separation by metal‐organic framework (MOF) membranes is an emerging research field. Their commercial application potential is however still rarely explored due in part to unsatisfied separation characteristics and difficulty in finding suitable applications. Herein, we report “sharp molecular sieving” properties of high quality isoreticular MOF‐1 (IRMOF‐1) membrane for CO2 separation from dry, CO2 enriched CO2/CH4 and CO2/N2 mixtures. The IRMOF‐1 membranes exhibit CO2/CH4 and CO2/N2 separation factors of 328 and 410 with CO2 permeance of 2.55 × 10−7 and 2.06 × 10−7 mol m−2 s−1 Pa−1 at feed pressure of 505 kPa and 298 K, respectively. High grade CO2 is efficiently produced from the industrial or lower grade CO2 feed gas by this MOF membrane separation process. The demonstrated “sharp molecular sieving” properties of the MOF membranes and their potential application in production of value‐added high purity CO2 should bring new research and development interest in this field. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-13T11:21:44.248577-05:
      DOI: 10.1002/aic.15367
       
  • Heterogeneous Fenton and Photo‐Fenton Oxidation for Paracetamol
           Removal using Iron Containing ZSM‐5 Zeolite as Catalyst
    • Authors: Filipa Velichkova; Henri Delmas, Bogdana Koumanova, Carine Julcour
      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 five hours, 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: 2016-06-13T11:21:43.297592-05:
      DOI: 10.1002/aic.15369
       
  • Oxidative dehydrogenation of butenes over Bi‐Mo and Mo‐V based
           catalysts in a two‐zone fluidized bed reactor
    • Authors: Julius Rischard; Robert Franz, Claudia Antinori, Olaf Deutschmann
      Abstract: The oxidative dehydrogenation of a 1‐butene/trans‐butene (1:1) mixture to 1,3‐butadiene was carried out in a two‐zone fluidized bed reactor using a Mo‐V‐MgO and a γ‐Bi2MoO6 catalyst. The significant operating conditions temperature, oxygen/butene molar ratio, butene inlet height and flow velocity were varied to gain high 1,3‐butadiene selectivity and yield. Furthermore, axial concentration profiles were measured inside the fluidized bed to gain insight into the reaction network in the two zones. For optimized conditions and with a suitable catalyst, the two‐zone fluidized bed reactor makes catalyst regeneration and catalytic reaction possible in a single vessel. In the lower part of the fluidized bed, the oxidation of coke deposits on the catalyst as well as the filling of oxygen vacancies in the lattice can occur. The oxidative dehydrogenation reaction takes place in the upper zone. Thorough particle mixing inside fluidized beds causes permanent particle exchange between both zones. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-13T11:21:37.507966-05:
      DOI: 10.1002/aic.15368
       
  • Design of Parallel Cyclones based on Stability Analysis
    • Authors: Chenxi Zhang; Qi Wang, Zhao Jia, Usman Muhammad, Weizhong Qian, Fei Wei
      Abstract: The uniform distribution of gas solids flow across parallel cyclones is required for high efficiency. In this study we introduced mass flow rate ratio between solids and gas (CT) to present multi‐phase interaction. And the direct Liapunov method is used to detect the instability of uniformity. Due to the special symmetry in this system, the criterion can be simplified into identifying the concavity (concave or convex) of pressure drop across a single cyclone with respect to CT. Then, based on the stability analysis of uniformity, a novel design principle is provided to prevent non‐uniform distribution at dense phase. The effect of geometrical factor, i.e. dimensionless vortex finder diameter dr, on the stability of uniformity has been further investigated. The phase diagram, illustrating the effects of both operational parameter (CT) and geometrical parameter (dr) on stability of uniformity is calculated to give a clue of designing a robust parallel cyclones system. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-10T03:41:32.281836-05:
      DOI: 10.1002/aic.15366
       
  • 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
      Abstract: Oil‐contaminated wastewater threatens our environment and health, thus novel membrane materials with low‐ or non‐fouling 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 RAFT method. The amphiphilic Poly(ether sulfone) (PES) membranes were then fabricated by blending with these copolymers via a facile coupled process of non‐solvent induced phase separation (NIPS) 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. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-10T03:35:33.782941-05:
      DOI: 10.1002/aic.15365
       
  • Flow Pattern Transition in Gas‐ Liquid Downflow through Narrow
           Vertical Tubes
    • Authors: Amit Kumar; Satyabrata Bhowmik, Subhabrata Ray, Gargi Das
      Abstract: The present report studies on the flow pattern transitions during vertical air water downflow through millichannels (0.83 ≤ Eӧtvӧs 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. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-09T18:51:25.025167-05:
      DOI: 10.1002/aic.15364
       
  • Effects of Ga doping on Pt/CeO2‐Al2O3 catalysts for propane
           dehydrogenation
    • Abstract: This paper describes catalytic consequencesThis paper describes catalytic consequences of Pt/CeO2‐Al2O3 catalysts promoted with Ga species for propane dehydrogenation. A series of PtGa/CeO2‐Al2O3 catalysts were prepared by a sequential impregnation method. The as‐prepared catalysts were characterized employing N2 adsorption‐desorption, X‐ray diffrtaction, temperature programmed reduction, O2 volumetric chemisorption, H2‐O2 titration, and transmission electron microscopy. We have shown that Ga3+ cations are incorporated into the cubic fluorite structure of CeO2, enhancing both lattice oxygen storage capacity and surface oxygen mobility. The enhanced reducibility of CeO2 is indicative of higher capability to eliminate the coke deposition and thus is beneficial to the improvement of catalytic stability. Density functional theory calculations confirm that the addition of Ga is prone to improve propylene desorption and greatly suppress deep dehydrogenation and the following coke formation. The catalytic performance shows a strong dependence on the content of Ga addition. The optimal loading content of Ga is 3 wt %, which results in the maximal propylene selectivity together with the best catalytic stability against coke accumulation. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-09T11:05:30.416226-05:
      DOI: 10.1002/aic.15339
       
  • Maldistribution susceptibility of monolith reactors: Case study of glucose
           hydrogenation performance
    • Abstract: In this work an ultrafast electron beam X‐ray modality was applied for the first time to characterize the gas–liquid Taylor flow inside each channel of an opaque honeycomb monolith structure ( 65 cpsi) for uG,S=0.1 … 0.5 m/s and uL,S=0.2 m/s. Significant spatial and temporal deviations in the phase holdup as well as in the gas bubble and liquid slug lengths were found. To evaluate the impact of Taylor flow maldistribution on the reactor performance, the data of more than 125,000 unit cells were used to simulate the reactor productivity in the hydrogenation of glucose. The results verify that a monolith reactor solely designed by using superficial velocities and empirical correlations for gas bubble and liquid slug lengths fails significantly in achieving high product selectivity and the desired conversion. The developed methods are a solid base to design and select proper distributors ensuring the favorable flow configurations for specific chemical processes. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-09T11:01:45.666942-05:
      DOI: 10.1002/aic.15334
       
  • Wetting forces and meniscus pinning at geometrical edges
    • Abstract: It is shown that complications in currently used optical measurements for wetting and flow resistance over edges can be circumvented by surface tension force measurements. These forces are measured by employing a modified Wilhelmy plate testing technique in which a plate with rectangular holes is immersed. The forces measured during immersion and emersion are subdivided into mass, buoyancy, and surface tension related parts, where the flow resistance when the meniscus passes horizontal faces and edges of the plate receives particular attention. Combining this experimental method with wetting theory, we show that we can predict and measure the full force curve for meniscus shape transitions over edge geometries under quasi‐static conditions. Moreover, wetting effects directly linked to surface defects can be detected qualitatively. We also point to the speed‐dependent rupture of metastable films formed during emersion. The measurement method designed is most relevant in cases where optical methods cannot be used. © 2016 The
      Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-09T10:45:36.10473-05:0
      DOI: 10.1002/aic.15341
       
  • The effect of shear‐thickening on the stability of slot‐die
           coating
    • Authors: Sunilkumar Khandavalli; Jonathan P. Rothstein
      Abstract: Slot‐die coating is an economical roll‐to‐roll processing technique with potential to revolutionize the fabrication of nano‐patterned thin films at high throughput. In this study, the impact of shear‐thickening of the coating fluid on the stability of slot‐die coating was investigated. For the coating fluid, a model system fumed silica nanoparticles dispersed in polypropylene glycol was chosen. These dispersions exhibit shear and extensional thickening characterized through steady shear and capillary break‐up measurements. The critical web velocity for the onset of coating defect for different flow rates was measured, while the type of coating defect was visualized using a high speed camera. For the shear thickening particle dispersions, the coating failed through the onset of a ribbing instability. The critical web velocity for the onset of coating defect was found to decrease with increasing particle concentration and increasing fluid viscosity. The minimum wet thickness was studied as a function of capillary number for the particle dispersions and compared with a series of Newtonian fluids with similar viscosities. In all cases, shear‐thickening behavior was found to stabilize coating by reducing the minimum wet coating thickness when compared against a Newtonian fluid with similar viscosity at the same capillary number. Conversely, the shear‐thinning fluids tested destabilized the coating by increasing the minimum wet thickness when compared against a Newtonian at the same capillary number. The impact of shear‐thickening on slot‐die coating was further studied by quantifying the evolution of the ribbing instability with increasing web speed and by conducting tests over a wide range of coating gaps. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-09T10:41:13.656602-05:
      DOI: 10.1002/aic.15336
       
  • Increasing selectivity of the hydroformylation in a miniplant: Catalyst,
           solvent, and olefin recycle in two loops
    • Abstract: The application of thermomorphic solvent systems offers the combination of homogeneous catalysis in a single phase and catalyst recovery via phase separation. To increase economic feasibility the minimization of waste streams and side reactions is desired. For this, a continuous process for the hydroformylation of 1‐dodecene in the solvent system DMF/n‐decane is shown. While the Rh/Biphephos catalyst is recycled in DMF in a first loop, the n‐decane and remaining olefins are separated from the product via distillation to form the second loop. In this process the need for additional solvent supply and the isomerization reaction of 1‐dodecene is reduced significantly. The reaction toward internal olefins decreases from initially 15 to 3%. The stable hydroformylation process with a yield of the linear hydroformylation product of 55% and l/b‐ratio of 95/5 is shown for 120 h. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-09T10:40:49.166481-05:
      DOI: 10.1002/aic.15345
       
  • Chord length distribution to particle size distribution
    • Authors: Ajinkya V. Pandit; Vivek V. Ranade
      Abstract: A simple model is presented to extract the particle size distribution (PSD) from the chord length distribution measured using a focused beam reflectance measurement probe. The model can be implemented using simple spread sheeting tools and does not require the description of additional parameters as opposed to previous models. The model was validated for two systems consisting of spherical ceramic beads by comparing model predicted PSD against the PSD obtained through image analysis (IA). Then, the model was evaluated by considering various systems consisting of irregularly shaped particles (sand/zinc dust/plasma alumina). Model predictions accurately predicted the mean but over‐predicted the variance of the PSD in comparison with the PSD obtained from IA. However, overall, a reasonable agreement was observed. Finally, the model was shown to be accurate in predicting PSD in comparison with the measured PSD for systems of practical relevance such as for paracetamol and p‐aminophenol crystals. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-09T10:31:06.656254-05:
      DOI: 10.1002/aic.15338
       
  • Hydrophobic Protic Ionic Liquids Tethered with Tertiary Amine Group for
           Highly Efficient and Selective Absorption of H2S from CO2
    • Abstract: Developing absorbents with both high absorption capacity of H2S and large selectivity of H2S/CO2 is very important for natural gas sweetening process. To this end, a class of novel hydrophobic protic ionic liquids containing free tertiary amine group as functional site for the absorption of H2S were designed in this work. They were facilely synthesized through a simple neutralization‐metathesis methodology by utilizing diamine compounds and bis(trifluoromethylsulfonyl)imide as the building blocks for cation and anion, respectively. Impressively, the solubility of H2S can reach 0.546 mol/mol (1 bar) and 0.225 mol/mol (0.1 bar), and the selectivity of H2S/CO2 can reach 37.2 (H2S solubility at 1 bar vs. CO2 solubility at 1 bar) and 15.4 (H2S solubility at 0.1 bar vs. CO2 solubility at 1 bar) in the hydrophobic protic ionic liquids at 298.2 K. Comparing the hydrophobic protic ionic liquids with other absorbents justifies their superior performance in the selective absorption of H2S from CO2. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-09T04:18:20.2391-05:00
      DOI: 10.1002/aic.15363
       
  • A Novel Feasibility Analysis Method for Black‐Box Processes using a
           Radial Basis Function Adaptive Sampling Approach
    • Authors: Zilong Wang; Marianthi Ierapetritou
      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 towards feasible region boundaries and regions where prediction uncertainty is high. In this paper, 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. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-08T10:41:09.774435-05:
      DOI: 10.1002/aic.15362
       
  • Energy optimization of water supply system scheduling: Novel MINLP model
           and efficient global optimization algorithm
    • Authors: Hanyu Shi; Fengqi You
      Abstract: This article is concerned with global optimization of water supply system scheduling with pump operations to minimize total energy cost. The scheduling problem is first formulated as a non‐convex mixed‐integer nonlinear programming (MINLP) problem, accounting for flow rates in pipes, operation profiles of pumps, water levels of tanks, and customer demand. Binary variables denote on–off switch operations for pumps and flow directions in pipes, and nonlinear terms originate from characteristic functions for pumps and hydraulic functions for pipes. The proposed MINLP model is verified with EPANET, which is a leading software package for water distribution system modeling. We further develop a novel global optimization algorithm for solving the non‐convex MINLP problem. To demonstrate the applicability of the proposed model and the efficiency of the tailored global optimization algorithm, we present results of two case studies with up to 4 tanks, 5 pumps, 5 check valves, and 21 pipes. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-08T10:25:43.827642-05:
      DOI: 10.1002/aic.15332
       
  • Development of soft‐sphere contact models for thermal heat
           conduction in granular flows
    • Authors: A. B. Morris; S. Pannala, Z. Ma, C. M. Hrenya
      Abstract: Conductive heat transfer to flowing particles occurs when two particles (or a particle and wall) come into contact. The direct conduction between the two bodies depends on the collision dynamics, namely the size of the contact area and the duration of contact. For soft‐sphere discrete‐particle simulations, it is computationally expensive to resolve the true collision time because doing so would require a restrictively small numerical time step. To improve the computational speed, it is common to increase the “softness” of the material to artificially increase the collision time, but doing so affects the heat transfer. In this work, two physically‐based correction terms are derived to compensate for the increased contact area and time stemming from artificial particle softening. By including both correction terms, the impact that artificial softening has on the conductive heat transfer is removed, thus enabling simulations at greatly reduced computational times without sacrificing physical accuracy. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-08T10:15:29.273557-05:
      DOI: 10.1002/aic.15331
       
  • Superstructure optimization of integrated fast
           
    • Authors: Zhihong Yuan; Mario R. Eden
      Abstract: Motivated by the apparent advantages of fast pyrolysis and gasification, a novel integrated biorefinery plant is systematically synthesized for coproducing premium quality liquid fuels and propylene. The required heat and fluidization promotion of the fast pyrolyzer are provided by hot syngas from the gasifier. Light gas and syngas from the fast pyrolyzer are finally converted to hydrocarbons via Fischer‐Tropsch synthesis. Multiple syngas production technologies, hydrocarbon production and downstream upgrading routes are incorporated within a superstructure optimization based process synthesis framework. This is the first article to investigate the benefits associated with the introduction of conventional catalytic cracking and dewaxing from a systems engineering perspective. Surrogate models describing the gasifiers and rigorous equations for Fischer‐Tropsch effluents validated by our experimental collaborator are introduced. Through investigation of five scenarios the primary parameters affecting overall economic performance are identified through ranking of the relevant candidates. Comparisons of the hybrid conversion route and stand‐alone routes are made. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-08T09:12:50.554547-05:
      DOI: 10.1002/aic.15337
       
  • Communication delays and data losses in distributed adaptive
           high‐gain EKF
    • Authors: Mohammad Rashedi; Jinfeng Liu, Biao Huang
      Abstract: In this work, we consider distributed adaptive high‐gain extended Kalman filtering for nonlinear systems subject to data losses and delays in communications. Specifically, we consider a class of nonlinear systems that consist of several subsystems interacting with each other via their states. A local adaptive high‐gain extended Kalman filter is designed for each subsystem and the distributed estimators communicate to exchange the information. Each subsystem estimator takes the advantage of a predictor accounting for the delays and data losses simultaneously. The predictor of each subsystem is used to generate state predictions of interacting subsystems for interaction compensation. To get a reliable prediction, the predictors are designed based on a prediction‐update algorithm. The convergence of the proposed distributed state estimation is ensured under sufficient conditions handling communication delays and data losses. Finally, a chemical process example is used to evaluate the applicability and effectiveness of the proposed design. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-07T19:00:30.411119-05:
      DOI: 10.1002/aic.15351
       
  • Systematic integrated process design and control of binary element
           reactive distillation processes
    • Abstract: Integrated process design and control of reactive distillation processes is considered through a computer‐aided framework. First, a set of simple design methods for reactive distillation column (RDC) that are similar in concept to nonreactive distillation design methods are extended to design‐control of RDCs. These methods are based on the element concept where the reacting system of compounds is represented as elements. When only two elements are needed to represent the reacting system of more than two compounds, a binary element system is identified. It is shown that the same design‐control principles that apply to a nonreacting binary system of compounds are also valid for a reactive binary system of elements for distillation columns. Application of this framework shows that designing the reactive distillation process at the maximum driving force results in a feasible and reliable design of the process as well as the controller structure. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-07T09:40:55.868365-05:
      DOI: 10.1002/aic.15322
       
  • Optimal Design of Solvents for Extractive Reaction Processes
    • Authors: Teng Zhou; Jiayuan Wang, Kevin McBride, Kai Sundmacher
      Abstract: It is well known that solvents can have significant effects on rates and equilibrium compositions of chemical reactions. The computer‐aided molecular design (CAMD) of solvents for heterogeneous liquid phase reactions is challenging due to multiple solvent effects on reaction and phase equilibria. In this work, we propose a CAMD methodology based on a genetic algorithm (GA) for identifying optimal solvents for liquid phase reactions where the objective is to maximize the reaction equilibrium conversion. In particular, a novel molecular encoding method is introduced to facilitate the construction and evaluation of solvent molecules in a defined structure space. The reliability of the method for fast identification of optimal reaction solvents is demonstrated for a selected biphasic esterification reaction. The proposed approach opens up new perspectives for intensifying extractive reaction processes via the purposeful design of solvent molecules. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-06T10:30:44.685521-05:
      DOI: 10.1002/aic.15360
       
  • A Mathematical Optimization Framework for the Design of Nanopatterned
           Surfaces
    • Authors: Christopher L. Hanselman; Chrysanthos E. Gounaris
      Abstract: The recent explosion of capabilities to fabricate nanostructured materials to atomic precision has opened many avenues for technological advances but has also posed unique questions regarding the identification of structures that should serve as targets for fabrication. One material class for which identifying such targets is challenging are transition‐metal crystalline surfaces, which enjoy wide application in heterogeneous catalysis. The high combinatorial complexity with which patterns can form on such surfaces calls for a rigorous design approach. In this paper, we formalize the identification of the optimal periodic pattern of a metallic surface as an optimization problem, which can be addressed via established algorithms. We conduct extensive computational studies involving an array of crystallographic lattices and structure‐function relationships, validating patterns that were previously known to be promising but also revealing a number of new, nonintuitive designs. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-06T03:20:59.009724-05:
      DOI: 10.1002/aic.15359
       
  • Mass‐Transfer Enhancement in Single Drop Extraction in the Presence
           of Magnetic Nanoparticles and Magnetic Field
    • Authors: Amid Vahedi; Asghar Molaei Dehkordi, Farzad Fadaei
      Abstract: Magnetite nanoparticles with an average particle size of 28.8 nm were synthesized, coated with oleic acid, and characterized using various techniques such as DLS, FT‐IR, SEM, XRD, VSM, and UV‐Vis analysis. A nanofluid consisting of synthesized nanoparticles and 5 wt.% acetic acid in toluene as the dispersed phase was prepared and used in the chemical test system, Toluene‐Acetic Acid‐Water, for the single drop extraction in the presence and absence of an external oscillating magnetic field. Influences of various operating and design parameters such as nanoparticle concentration, drop diameter, and the applied current and frequency on the overall mass‐transfer coefficients for the mass‐transfer direction from d→c were investigated carefully. The obtained results were used to propose a general correlation for the mass‐transfer enhancement. It was found that the maximum mass‐transfer enhancement compared to that obtained in the absence of nanoparticles and the oscillating magnetic field is about 259%. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-06T03:20:43.589863-05:
      DOI: 10.1002/aic.15357
       
  • Tensorial Navier‐Slip Boundary Conditions for Patterned Surfaces for
           Fluid Mixing: Numerical Simulations and Experiments
    • Authors: Hye Kyeong Jang; Young Ju Kim, Nam Sub Woo, Wook Ryol Hwang
      Abstract: Navier‐slip boundary condition has been investigated for patterned surfaces with various grooves for the application to fluid mixing by controlling flow patterns. Simple tensorial expression is applied for anisotropically patterned surfaces and effective slip lengths for various grooves have been evaluated for a wide range of Reynolds numbers and aspect ratios using a flow rate matching technique. By doing so, the applicability of the effective tensorial slip model has been presented that replaces physical surface patterns to reduce computational cost significantly. Using a simple model agitator with a rotating disk, modification of flow characteristics with various alignment angles of the patterned surface has been investigated. We report a critical Reynolds number of O(1) for flows in agitators, below which effective slip dominates over fluid inertia. Patterned poly(dimethylsiloxane) (PDMS) sheets are fabricated using a compression‐molding/soft‐lithography technique and flow visualization with laser‐induced fluorescence reveals controllability of flow patterns with the patterned surface. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-06T03:15:37.477301-05:
      DOI: 10.1002/aic.15355
       
  • Discrete Particle Modeling of Lateral Jets into a Packed Bed and
           Micromechanical Analysis of the Stability of Raceways
    • Authors: Q.F. Hou; D.Y. E, A.B. Yu
      Abstract: Gas jets are often used to promote heat and mass transfer by forming raceways or circulating regions in a packed bed. Such an operation is common and critical in many processes. Multiple raceways can interact and be affected by the formation of different flow zones. This work develops a multiscale model to examine the formation and the stability of raceways and the underlying micromechanics. Four states are observed in the fluidized flow regime. More fundamentally, a critical bed width for the observation of different flow zones and states is found through numerical simulations and a theoretical analysis. Finally, the complicated transitions between different flow states are examined at a bed scale, and two general trends of the averaged solid velocity are found. The findings from the multiscale model are useful both scientifically for the understanding of state transitions and practically for the design and the operation of relevant chemical reactors. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-06T03:15:30.198216-05:
      DOI: 10.1002/aic.15358
       
  • Catalytic Dehydration of Glucose to 5‐Hydroxymethylfurfural with a
           Bifunctional Metal‐Organic Framework
    • Authors: Ye Su; Ganggang Chang, Zhiguo Zhang, Huabin Xing, Baogen Su, Qiwei Yang, Qilong Ren, Yiwen Yang, Zongbi Bao
      Abstract: Glucose conversion to 5‐hydroxymethylfurfural (HMF) generally undergoes catalytic isomerization reaction by Lewis acids followed by the catalytically dehydrated to HMF with Brӧnsted acid/base. In this work, a sulfonic acid functionalized metal‐organic frameworks MIL‐101(Cr)‐SO3H containing both Lewis acid and Brӧnsted acid sites, was examined as the catalyst for γ‐valerolactone‐mediated cascade reaction of glucose dehydration into HMF. Under the optimal reaction conditions, the batch heterogeneous reaction gave a HMF yield of 44.9% and selectivity of 45.8%. Reaction kinetics suggested that the glucose isomerization in GVL with 10 wt% water follows the second‐order kinetics with an apparent activation energy of 100.9 kJ mol−1. Continuous reaction in the fixed‐bed reactor showed that the catalyst is highly stable and able to provide a steady HMF yield. This work presents a sustainable and green process for catalytic dehydration of biomass‐derived carbohydrate to HMF with a bi‐functional metal‐organic framework. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-06T03:15:26.762499-05:
      DOI: 10.1002/aic.15356
       
  • A trust region filter method for glass box/black box optimization
    • Authors: John P. Eason; Lorenz T. Biegler
      Abstract: Modern nonlinear programming solvers can be utilized to solve very large scale problems in chemical engineering. However, these methods require fully open models with accurate derivatives. In this article, we address the hybrid glass box/black box optimization problem, in which part of a system is modeled with open, equation based models and part is black box. When equation based reduced models are used in place of the black box, NLP solvers may be applied directly but an accurate solution is not guaranteed. In this work, a trust region filter algorithm for glass box/black box optimization is presented. By combining concepts from trust region filter methods and derivative free optimization, the method guarantees convergence to first‐order critical points of the original glass box/black box problem. The algorithm is demonstrated on three comprehensive examples in chemical process optimization. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-03T09:31:33.460171-05:
      DOI: 10.1002/aic.15325
       
  • Deep oxidative–extractive desulfurization of fuels using
           benzyl‐based ionic liquid
    • Authors: Mingxia Li; Zhiyong Zhou, Fan Zhang, Wenshuai Chai, Lele Zhang, Zhongqi Ren
      Abstract: Four benzyl‐based ionic liquids (ILs) were synthetized and used for deep desulfurization of model oil and real diesel fuel. The removal efficiencies of benzothiophene (BT) and dibenzothiophene (DBT) with [Bzmim][NTf2] and [Bzmim][SCN] as extractants are higher than that with [Bzmp][NTf2] and [Bzmp][SCN] as extractants. The desulfurization capability follows the Nernst's Law. A reactive extraction mathematical model for desulfurization was established. An oxidative‐extractive two‐step deep desulfurization method was developed. DBT was first oxidized by H2O2 with CH3COOH as catalyst and then the unoxidized DBT and uncrystallized dibenzothiophene sulfoxide (DBTO2) in model oil were extracted by [Bzmim][NTf2], and finally the removal efficiency was 98.4% after one‐stage extraction. Besides, the removal efficiency of 4,6‐DMDBT was 96.4% after oxidation and one‐stage extraction processes. Moreover, the oxidative‐extractive two‐step deep desulfurization method was also effective for desulfurization of diesel fuel. The removal efficiency of sulfur reached up to 96% after oxidation and three‐stage cross‐current extraction processes. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-03T09:26:52.683326-05:
      DOI: 10.1002/aic.15326
       
  • A novel consolidation method to measure powder flow properties using a
           small amount of material
    • Authors: Sara Koynov; Fernando J. Muzzio, Benjamin J. Glasser
      Abstract: Bulk flow property characterization often requires large powder samples (tens to hundreds of grams). However, many applications have limited sample availability, due to cost, material availability, safety concerns, etc. Therefore, reducing the amount of required material is of interest. A novel compressibility method is introduced using less than 50 mg, for the materials studied here. The effect of particle size and cohesion due to capillary forces are determined using a small‐scale compressibility cell mounted on a texture analyzer. It is found that the powder bed consolidation occurred in two regimes, described using the Walker and Heckel equations. The small‐scale compressibility method was compared to known behavior at larger scales and validated against the FT4 compressibility test. It was found that bulk behavior could be observed using the small‐scale compressibility method. Additional behavior caused by small‐scale events, which are averaged out in large‐scale measurements, are revealed in the small‐scale device introduced here. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-03T09:21:55.573467-05:
      DOI: 10.1002/aic.15321
       
  • Catalytic decomposition of propellant N2O Over Ir/Al2O3 catalyst
    • Authors: Jian Lin; Lin Li, Xiaoli Pan, Xiaodong Wang, Yu Cong, Tao Zhang, Shaomin Zhu
      Abstract: N2O, as a green propellant alternative to N2H4, shows potential application in satellite propulsion system. The state of Ir species and the reaction behaviors on Ir/Al2O3 in the oxidative environment during N2O decomposition were identified here. Two types of Ir sites existed in this catalyst and affected the process of N2O decomposition. The strong Ir sites facilitated the dissociative adsorption of N2O to form N2 and adsorbed O atoms with adsorption heat of as high as 281 kJ/mol, which promoted the desorption of adsorbed O atoms and favored the self‐sustaining decomposition of N2O by raising the catalyst bed temperature. The other Ir sites interacted weakly with O atoms but facilitated their combination to form O2. The Ir/Al2O3 catalyst then exhibited an excellent performance in initiating the decomposition of N2O at low temperature of 200°C and good stability in 0.1 N microthruster for orbit adjustment and attitude control of satellite. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-03T09:15:56.804678-05:
      DOI: 10.1002/aic.15324
       
  • Droplet Formation of H2SO4/Alkane System in a T‐junction
           Microchannel: Gravity Effect
    • Authors: Liantang Li; Jisong Zhang, Kai Wang, Jianhong Xu, Guangsheng Luo
      Abstract: A special system of concentrated sulfuric acid (H2SO4) and n‐hexane was used to study the droplet formation in a glass T‐junction microchannel with H2SO4 as the continuous phase. The effects of capillary number, flow ratio, and viscosity ratio on the droplet formation were investigated. The effect of gravity was explored by changing the flow direction in the microchannel. Results showed that the formation of transition flow pattern from squeezing to dripping is much easier for this special system compared with common aqueous/organic systems. This phenomenon is due to the considerably higher viscosity of H2SO4 than that of common aqueous phase and the higher density difference of the system compared with those of common systems. In addition to capillary number and flow ratio, gravity evidently affects the formation of droplets and flow patterns. The droplet size is smaller than that during the horizontal flow when the flow direction is consistent with gravity. By contrast, flow direction contrary to that of gravity results in larger droplet size than that at horizontal flow. This phenomenon provides guidance on the operation of these special systems in microchannels. Finally, mathematical models of droplet size at different flow patterns have been established, and these models can predict droplet size very well. This study could be helpful to extend the application of microreactors to new working systems. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-03T03:30:38.426784-05:
      DOI: 10.1002/aic.15354
       
  • Kriging meta‐model assisted calibration of computational fluid
           dynamics models
    • Authors: Olumayowa T. Kajero; Rex B. Thorpe, Tao Chen, Bo Wang, Yuan Yao
      Abstract: Computational fluid dynamics (CFD) is a simulation technique widely used in chemical and process engineering applications. However, computation has become a bottleneck when calibration of CFD models with experimental data (also known as model parameter estimation) is needed. In this research, the kriging meta‐modelling approach (also termed Gaussian process) was coupled with expected improvement (EI) to address this challenge. A new EI measure was developed for the sum of squared errors (SSE) which conforms to a generalised chi‐square distribution and hence existing normal distribution‐based EI measures are not applicable. The new EI measure is to suggest the CFD model parameter to simulate with, hence minimising SSE and improving match between simulation and experiments. The usefulness of the developed method was demonstrated through a case study of a single‐phase flow in both a straight‐type and a convergent‐divergent‐type annular jet pump, where a single model parameter was calibrated with experimental data. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-03T03:30:33.83024-05:0
      DOI: 10.1002/aic.15352
       
  • Non‐recirculating flow of a yield stress fluid around a circular
           cylinder in a Poiseuille flow
    • Authors: Hamdullah Ozogul; Pascal Jay, Albert Magnin
      Abstract: Although yield stress fluids are very present today in everyday life and in industry, their flow behavior is still poorly understood and the databases are incomplete at this time. The present experimental and numerical study focuses on laminar non‐recirculating flows of an elastoviscoplastic model fluid in a rectangular duct. An original experimental set‐up has been developed. The PIV method is used for analyzing the kinematical fields. Results provided concern the morphology of the flow and the evolution of the velocity field around a cylindrical obstacle. Information is provided on the size of the rigid zones where the fluid behaves as a solid. The experimental data are compared with numerical results involving a regularized Herschel‐Bulkley viscoplastic model. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-03T03:25:44.439404-05:
      DOI: 10.1002/aic.15350
       
  • The application of dynamic modeling for thermal risks analysis of the
           acid‐catalyzed hydrolysis of glycidol
    • Abstract: The aim of this work was to determine the limits of safe operation of CSTR (Continuous Flow Stirred‐Tank Reactor) for the acid‐catalyzed hydrolysis of glycidol. The stability analysis was performed by dynamic modelling. The obtained results were compared with the experimental data reported in the open literature. For this purpose, dimensionless variables and parameters were introduced and unstable material and energy balances were defined. The system equations were solved using Matcont (Matlab® software). Thus, bifurcation diagrams (in one and two dimensions) were mapped. All different dynamic states were identified and studied (thermal stability and instability, with unique and multiple solutions; Hopf bifurcations; turning points and envelope of periodic solutions). Finally, the intrinsic thermal unstable and cycle behavior of the acid‐catalyzed hydration of glycidol to produce glycerol was identified. The appropriate conditions to guarantee safe operation of CSTR were found. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-03T03:25:26.075512-05:
      DOI: 10.1002/aic.15353
       
  • Issue information
    • Abstract: Cover illustration. Scanning electron micrographs of paint cross sections that show a more uniform distribution of TiO2 in paints made with EVOQUETM Pre‐Composite Polymer (right) compared to conventional binder (left). Micrographs by John Reffner and Phillip Lin, collage created by Melinda Keefe. 10.1002/aic.15211
      PubDate: 2016-06-02T09:25:26.672565-05:
      DOI: 10.1002/aic.14993
       
  • Cyclic operation strategies in inclined and moving packed
           beds—Potential marine applications for floating systems
    • Abstract: The hydrodynamics of a periodically operated packed bed subjected to column oscillations and obliquity was studied. Electrical capacitance tomography (ECT) and capacitance wire mesh sensors were employed to measure the local instantaneous liquid saturation in stationary slanted and moving packed beds, respectively. A swell simulator with six‐degree‐of‐freedom motions was applied to emulate the behavior of floating packed beds. The results revealed that column inclination from the vertical position considerably decayed liquid waves excited by different cyclic operation strategies. However, ON–OFF liquid and gas/liquid alternating cyclic operations showed an attempt to conserve wave identity in the slanted bed and to decrease phase maldistribution resulting from bed inclination. It was also found that symmetric and non‐symmetric split ratios of ON–OFF liquid cyclic mode were able to noticeably decrease fluid maldistribution in the oscillating packed bed. This study opens up possible prospects for process intensification of floating packed bed reactors and contactors. © 2016 American Institute of Chemical Engineers AIChE J, 2016
      PubDate: 2016-06-02T09:18:32.600286-05:
      DOI: 10.1002/aic.15327
       
  • Global optimization of an industrial gas network operation
    • Abstract: Air Liquide operates several industrial gas pipeline networks around the world, connecting air separation plants to customers of industrial gases. The operation of such a network of plants, pipelines and customers is complicated due to fluctuating electricity prices and customer demands. We describe a complex industrial problem for real‐time optimization of network operations in the presence of these challenges. We then summarize a concerted modeling and algorithmic effort toward global optimization of this model. The resulting advances include development of a regression‐based fully‐deterministic nonconvex optimization model, a tool for diagnosing infeasibilities during model development, reformulations and scaling to make the model more amenable for optimization, and development of strengthened relaxations for its efficient solution. We provide details on the development of these tools and techniques that facilitated the solution of this model in a reasonable computational time with the global solver BARON. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-31T04:20:30.722459-05:
      DOI: 10.1002/aic.15344
       
  • Erratum
    • Abstract: This is a correction for “Liao, Z. W.; Hong, X. D.; Jiang, B. B.; Wang, J. D.; Yang, Y. Y. Novel graphical tool for the design of the heat integrated water allocation networks. AIChE Journal, 62, 670–686, 2016 (
      DOI 15049).” 1. The figure (Figure 11) on page 676 is incorrect. The correct figure is shown as follow: Figure 11. Network structure of example 1‐WAN4 (TFW2=335K) with four heat exchangers. 2. The figure (Figure 12) on page 677 is incorrect. The correct figure is shown as follow: Figure 12. Network structure of example 1‐WAN4 (TFW2=335K) with three heat exchangers. 3. The note ‘10.478' in Figure 19 on page 680 should be replaced by ‘10.476'. 4. The note ‘9.286 kg/s' should be added for WW1 in Figure 20 on page 680. 5. The note ‘22.761' in Figure 22 on page 681 should be replaced by ‘24.761'. 6. The table (Table 2) on page 682: Atotal for case 2 should be 3.915 not 3.907. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-31T04:17:56.338207-05:
       
  • Tailored Synthesis of Macroporous Pt/WO3 Photocatalyst with Nanoaggregates
           via Flame Assisted Spray Pyrolysis
    • Authors: Osi Arutanti; Aditya Farhan Arif, Ratna Balgis, Takashi Ogi, Ferry Iskandar, Kikuo Okuyama
      Abstract: High‐surface‐area macroporous WO3 particles with deposited Pt (Pt/WO3) were successfully synthesized for the first time, using flame‐assisted spray pyrolysis. Nanoparticle aggregates‐like structures (nanoaggregates) were formed, although a salt precursor was used for the synthesis. The macroporous structure was tailored by changing the mass ratio of the polystyrene template to ammonium tungstate pentahydrate. The cavities between the nanoaggregates formed mesopores, which increased the surface area. The presence of meso‐ and macro‐pores in the synthesized Pt/WO3 particles improved their photocatalytic activities in visible‐light‐induced photodegradation of rhodamine B. The combination of a high surface area and the presence of an in situ‐deposited Pt cocatalyst gave a high photodecomposition rate, approximately 9.6 times higher than that achieved with dense WO3 particles. This research provides a promising strategy for synthesizing submicron particles with high surface areas at a high production rate, and is suitable for industrial applications. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-31T04:15:26.121318-05:
      DOI: 10.1002/aic.15349
       
  • Multi‐scenario Robust Online Optimization and Control of
           Fed‐batch Systems via Dynamic Model‐based Scenario Selection
    • Abstract: The manuscript proposes a novel robust methodology for the model‐based online optimization/optimal control of fed‐batch systems, which consists of two different interacting layers executed asynchronously. The first iteratively computes robust control actions online via multi‐scenario stochastic optimization while the second iteratively re‐estimates the optimal scenario map after every single/every certain number of control action/actions. The novelty of the approach is twofold: (I) the scenario map is optimally computed/updated based on probabilistic information on the process model uncertainty as well as the sensitivity of the controlled system to the uncertain parameters; and (II) the scenario set is dynamically re‐estimated, thus accounting for the effect of disturbances and changes in the operating conditions of the target process. The proposed approach is applied to a fed‐batch Williams‐Otto process and compared to an existing multi‐scenario optimization/control algorithm as well as a non‐robust optimization/control strategy to draw conclusions about which method is more effective. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-31T04:11:15.177278-05:
      DOI: 10.1002/aic.15346
       
  • Block Adaptive Kernel Principal Component Analysis for Nonlinear Process
           Monitoring
    • Authors: Lei Xie; Zhe Li, Jiusun Zeng, Uwe Kruger
      Abstract: On‐line modeling of multivariate nonlinear system based on multivariate statistical methods has been studied extensively due to its industrial requirements. In order to further increase the modeling efficiency a fast Block Adaptive Kernel Principal Component Analysis (BAKPCA) algorithm is proposed. Comparing with the existing work the proposed algorithm (i) does not rely on iterative computation in the calculating process (ii) combines the up‐ and downdating operations to become a single one (iii) and describes it as a series of rank‐1 modification. In addition (iv) the updation of the eigenvalues and eigenvectors is of O(N2)$with high accuracy. The computational complexity analysis and the numerical study shows the derived strategy possesses better online adaptive modeling abilities to the time‐varying nonlinear variable interrelationships in process monitoring. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-31T04:10:59.178387-05:
      DOI: 10.1002/aic.15347
       
  • Polymorph Selection by Continuous Crystallization
    • Authors: Thomas C. Farmer; Corinne L. Carpenter, Michael F. Doherty
      Abstract: This paper is motivated by a remarkable observation reported recently by Myerson, Trout, and co‐workers that continuous crystallization is capable of producing metastable polymorphs in stable steady‐state operation. We explain why this phenomenon occurs and give simple design rules for reproducing it in other polymorphic systems. A linear stability analysis gives simple functions of parameters for which one can continuously produce thermodynamically metastable products based only on the relative polymorph dynamics. We demonstrate agreement with with two sets of experimental data; L‐glutamic acid grown from aqueous solution and p‐aminobenzoic acid also grown from aqueous solution. For many polymorphic compounds, engineering a process to produce a desired polymorph is as simple as finding a reasonable operating point for the continuous mixed‐suspension mixed‐product removal (MSMPR) crystallization process (temperature, residence time, initial supersaturation, etc.) according to the rules reported in this article. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T03:30:49.966741-05:
      DOI: 10.1002/aic.15343
       
  • Cobalt Molybdenum Oxide Catalysts for Selective Oxidation of Cyclohexane
    • Authors: Ashish P. Unnarkat; Tam Sridhar, Huanting Wang, Sanjay Mahajani, Akkihebbal K. Suresh
      Abstract: Oxidation of cyclohexane has been carried out using molecular oxygen over cobalt molybdenum oxide (CoMoO4) catalysts in solvent free conditions. The catalysts were prepared using citrate method with three different molar ratios of Co:Mo, 1:1, 1:2 and 2:1 along with individual oxides for comparative studies. While all the catalysts showed significant activity and selectivity, CoMoO4 with 1:1 ratio showed the best performance compared to the others with a conversion of 7.38%, with selectivity to cyclohexanol and cyclohexanone (KA oil) of 94.3%, in 1h. The performance of the catalyst, has been studied as a function of oxygen pressure, reaction temperature, and catalyst loading. It was observed that the catalyst deactivates during the course of the reaction. The reasons for deactivation and methods for restoring the activity have been studied. A kinetic model is presented that captures the complex kinetics and matches well with the experimental data. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T03:30:41.712326-05:
      DOI: 10.1002/aic.15335
       
  • On Optimal Sensing and Actuation Design for an Industrial Scale Steam
           Methane Reformer Furnace
    • Authors: Ankur Kumar; Michael Baldea
      Abstract: The spatial temperature distribution in the highly energy‐intensive furnace unit in a steam reforming‐based hydrogen manufacturing plant determines the energy efficiency of the plant. While the fuel distribution among the burners can be manipulated to control the furnace temperature distribution, adequate temperature measurements is a prerequisite. Typical furnaces have hundreds of tubes and burners, and economic considerations dictate that the number of temperature sensors and flow actuators required for automatic temperature optimization be minimized. In this paper, we investigate several formulations for the design of the optimal sensor and actuation configurations for an industrial furnace. We initially formulate the optimal sensor placement problem as a bi‐level optimization problem, and exploit the problem structure to obtain an equivalent MILP formulation. We then provide an extension to the combined sensor and actuator placement. We demonstrate the efficacy of our approach through simulation case studies based on industrial data. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T03:30:30.050024-05:
      DOI: 10.1002/aic.15333
       
  • Assessing the capacity of local ecosystems to meet industrial demand for
           ecosystem services
    • Authors: Varsha Gopalakrishnan; Bhavik R. Bakshi, Guy Ziv
      Abstract: Despite the importance of ecosystems, engineering activities continue to ignore or greatly undervalue their role. Consequently, engineered systems often overshoot nature's capacity to support them, causing ecological degradation. Such systems tend to be inherently unsustainable, and they often fail to benefit from nature's ability to provide essential goods and services. This work explores the idea of including ecosystems in chemical processes, and assesses whether such a techno‐ecological synergistic system can operate within ecological constraints. The demand for ecosystem services is quantified by emissions and resources used, while the supply is provided by ecosystems on the manufacturing site. Application to a biodiesel manufacturing site demonstrates that ecosystems can be economically and environmentally superior to conventional technologies for making progress toward zero emissions and net positive impact manufacturing. These results highlight the need for shifting the paradigm of engineering from that of dominating nature to embracing nature and respecting its limits. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-27T18:50:31.475421-05:
      DOI: 10.1002/aic.15340
       
  • Optimization Models for Planning Shale Gas Well Refracture Treatments
    • Authors: Diego C. Cafaro; Markus G. Drouven, Ignacio E. Grossmann
      Abstract: Refracturing is a promising option for addressing the characteristically steep decline curves of shale gas wells. In this work we propose two optimization models to address the refracturing planning problem. First, we present a continuous‐time nonlinear programming (NLP) model based on a novel forecast function that predicts pre‐ and post‐treatment productivity declines. Next, we propose a discrete‐time, multi‐period mixed‐integer linear programming (MILP) model that explicitly accounts for the possibility of multiple refracture treatments over the lifespan of a well. In an attempt to reduce solution times to a minimum, we compare three alternative formulations against each other (big‐M formulation, disjunctive formulation using Standard and Compact Hull‐Reformulations) and find that the disjunctive models yield the best computational performance. Finally, we apply the proposed MILP model to two case studies to demonstrate how refracturing can increase the expected recovery of a well and improve its profitability by several hundred thousand USD. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-23T03:35:32.448759-05:
      DOI: 10.1002/aic.15330
       
  • A Study on hydrodynamic characteristics in a Φ38 pulsed extraction
           column by four‐sensor optical fiber probe
    • Authors: Yukun Yuan; Yang Gao
      Abstract: Accurate prediction of dispersed phase droplet behavior is crucial to the design and scaling‐up of an extraction column. In this paper, 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 38mm‐diameter pulsed sieve‐plate extraction column. Water and kerosene were used as continuous and dispersed phases, respectively. The influences of the pulsed intensity, continuous and dispersed phase superficial velocity 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. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-19T03:51:09.451315-05:
      DOI: 10.1002/aic.15328
       
  • Viscosity and drop size evolution during suspension polymerization
    • Authors: Michal Vonka; Giuseppe Storti, Miroslav Soos
      Abstract: Annually, suspension polymerization produces kilotons of material with properties given by process conditions. The prediction of material properties requires a relevant description of processes on various scales from the molecular level to reactor design. The polymerization occurring on the molecular scale was described by a kinetic scheme of homopolymerization. The molecular level was connected to the meso‐scale by the viscosity evolution inside a single monomer/polymer drop. The viscosity model follows the change in the reaction mixture composition and its predictions were validated by the rheology measurements. During the suspension polymerization, the viscosity evolution affects the dispersion breakage and coalescence on the meso‐scale, which is closely connected to the flow conditions given by the reactor design and operation conditions. This complex problem was described by a coupled CFD‐PBE model. The presented study proposes a modelling approach to control the suspension polymerization by stirring speed to obtain the desired drop size. Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Ut purus elit, vestibulum ut, placerat ac, adipiscing vitae, felis. Curabitur dictum gravida mauris. Nam arcu libero, nonummy eget, consectetuer id, vulputate a, magna. Donec vehicula augue eu neque. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Mauris ut leo. Cras viverra metus rhoncus sem. Nulla et lectus vestibulum urna fringilla ultrices. Phasellus eu tellus sit amet tortor gravida placerat. Integer sapien est, iaculis in, pretium quis, viverra ac, nunc. Praesent eget sem vel leo ultrices bibendum. Aenean faucibus. Morbi dolor nulla, malesuada eu, pulvinar at, mollis ac, nulla. Curabitur auctor semper nulla. Donec varius orci eget risus. Duis nibh mi, congue eu, accumsan eleifend, sagittis quis, diam. Duis eget orci sit amet orci dignissim rutrum This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-17T10:30:25.96914-05:0
      DOI: 10.1002/aic.15320
       
  • Reliable mixture critical point computation using polynomial homotopy
           continuation
    • Authors: Hythem Sidky; Dhagash Mehta, Jonathan Whitmer
      Abstract: The numerical computation of multicomponent mixture critical points has been the subject of much study due to their theoretical and practical importance. Both deterministic and stochastic methods have been applied with varying degrees of reliability and robustness. In this work, we utilize numerical polynomial homotopy continuation (NPHC) to reliably identify all mixture critical points. This method is unique due to its robustness, initialization‐free nature and ease of parallelization. For a given system of equations, all complex solutions are found. Computational times are also found to be invariant to mixture composition. We validate this technique against previous work and extend the method to mixtures of up to eight components. NPHC is shown to be a modern and powerful technique which offers mathematical reliability at a moderate computational cost. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-14T08:55:26.661562-05:
      DOI: 10.1002/aic.15319
       
  • Dynamic population balance and flow models for granular solids in a linear
           vibrating screen
    • Abstract: Vibrating screens are a widely applied form of particle separations. In spite of this significance, their understanding is still an obstacle. Three approaches were used to characterize the flow of granular material in a linear vibrating screen. The statistical model, mass action, and kinetic model based on conservation of momentum were derived. Experiments were then conducted on a multi‐sized prototype screen and glass beads of sizes 0.75, 1,2,3mm. Deck inclinations were varied over 7.5,12.5 and 17.5°, and frequencies over 7, 15 and 20Hz. A total of 72 feed batches and a constant power of 50 Watt was used. The experimental data was then used to validate the models. The three models provided accurate flow prediction over the screens. Additionally, the kinetic model also provided a basis for optimal design of the screening unit operation, by allowing manipulation of seven design variables to obtain a 95‐100% efficient vibrating screen. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-14T08:55:22.32213-05:0
      DOI: 10.1002/aic.15318
       
  • Improving dissolution kinetics of pharmaceuticals by fluidized bed
           impregnation of active pharmaceutical ingredients
    • Authors: Plamen I. Grigorov; Benjamin J. Glasser, Fernando J. Muzzio
      Abstract: Investigational drugs are increasingly becoming less soluble in aqueous media thus presenting real challenges during development. Previous work has successfully demonstrated the manufacturing of pharmaceuticals using fluidized‐bed (FB) impregnation of APIs onto porous carriers. This study demonstrates the usefulness of FB impregnation in formulating poorly‐soluble drugs. We show that dissolution of Fenofibrate is greatly improved by FB impregnation onto Neusilin®, a synthetic amorphous form of magnesium alumino‐metasilicate. We impregnate Neusilin® for range of loadings and examine Fenofibrate's physical state. Dissolution of impregnated formulations is drug‐loading dependent and loadings below 40% show great improvement (decrease) in release time compared to physical blend. Release times are further improved by milling. We also examine feasibility of co‐impregnating Fenofibrate with additives and observe stability (1.5 years) of the amorphous form of Fenofibrate inside Neusilin®. This stabilization significantly improves Fenofibrate's dissolution kinetics, making our formulation comparable to one of the current market formulations, TriCor® tablets. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-14T03:15:43.580711-05:
      DOI: 10.1002/aic.15312
       
  • A framework for interpreting the coarsening and structural evolution of
           two co‐continuous immiscible viscous fluids
    • Authors: Lee P McMaster
      Abstract: Experimental data from multiple studies show the coarsening of co‐continuous, high interfacial tension fluid systems is driven by capillary instabilities. Coarsening of low interfacial tension systems follows viscosity ratio dependence consistent with the pinch‐off of suspended short filaments although there is uncertainty of this interpretation. The attenuation of coarsening rates for both types follows a common dependence on phase volume fraction and viscosity ratio. Dimensional analysis provides an interpretation of the transition from linear coarsening to slower non‐linear coarsening as a balance of interfacial tension driven flow and a critical level of interconnectivity. The slowdown of coarsening is consistent with the formation of discrete domains which subsequently coexist with the remaining co‐continuous structure. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-14T03:15:40.224768-05:
      DOI: 10.1002/aic.15310
       
  • Phase behavior of system methane + hydrogen sulfide
    • Abstract: An accurate description of the phase behavior of the CH4+H2S system is given for temperatures from 70 K to the critical temperature of H2S and pressures up to 250 MPa. The study includes the solid phases of CH4 and H2S. A global pressure‐temperature diagram is presented. The types of temperature‐composition and pressure‐composition phase diagrams that can be encountered in the studied temperature and pressure ranges have been described. The temperature and pressure ranges where the phase behavior of the system changes have been identified and a representative phase diagram is presented for each range. Phase diagrams have been obtained through the solid‐liquid‐vapor equation of state proposed by Yokozeki. The parameters of the equation of state have been regressed on all the available phase equilibrium data for the considered system. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-14T03:15:25.080288-05:
      DOI: 10.1002/aic.15311
       
  • Applicability of the Linearized Theory of the Maxwell‐Stefan
           Equations
    • Authors: Paul S. Weber; Dieter Bothe
      Abstract: The present article aims for a better understanding of the applicability of the linearized theory of the Maxwell‐Stefan equations for multi‐component diffusion. An analysis of the theory's accuracy is performed with respect to the classical two‐bulb diffusion experiments by Duncan and Toor, from which the results are transferred to more general scenarios. It is shown that for an accurate linearized theory it is essential to have a quasi‐stationary and quasi‐one‐dimensional flux, and also a so‐called reference point. Two examples illustrating the theory's failure in case of unmet prerequisites are presented: a three‐bulb configuration and a two‐dimensional diffusion case. For the first setup the linearized theory results in negative concentrations, for the second it requires influxes at openings that are actually outlets. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-12T04:16:54.190024-05:
      DOI: 10.1002/aic.15317
       
  • In‐situ cross‐linked PVDF membranes with enhanced mechanical
           durability for vacuum membrane distillation
    • Abstract: A novel and effective one‐step method has been demonstrated to fabricate cross‐linked polyvinylidene fluoride (PVDF) membranes with better mechanical properties and flux for seawater desalination via vacuum membrane distillation (VMD). This method involves the addition of two functional non‐solvent additives; namely, water and ethylenediamine (EDA), into the polymer casting solution. The former acts as a pore forming agent, while the latter performs as a cross‐linking inducer. The incorporation of water tends to increase membrane flux via increasing porosity and pore size but sacrifices membrane mechanical properties. On the other hand, the presence of EDA enhances membrane mechanical properties through in‐situ cross‐linking reaction. Therefore, by synergistically combining the effects of both functional additives, the resultant PVDF membranes have shown good MD performance and mechanical properties simultaneously. The parameters that affect the cross‐link reaction and membrane mechanical properties such as reaction duration and EDA concentration have been systematically studied. The membranes cast from an optimal reaction condition comprising 0.8 wt% EDA and 3‐hour reaction not only shows a 40% enhancement in membrane Young's Modulus compared to the one without EDA but also achieves a good VMD flux of 43.6 L/m2‐h at 60 oC. This study may open up a totally new approach to design next‐generation high performance MD membranes. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-12T04:16:43.1863-05:00
      DOI: 10.1002/aic.15316
       
  • Au/TS‐1 Catalyst for Propene Epoxidation with H2/O2: A Novel
           Strategy to Enhance Stability by Tuning Charging Sequence
    • Authors: Xiang Feng; Yibin Liu, Yichuan Li, Zhihua Zhang, Xuezhi Duan, De Chen, Xinggui Zhou, Chaohe Yang
      Abstract: For propene epoxidation with H2 and O2, the catalytic performance of Au/TS‐1 catalyst is extremely sensitive to preparation parameters of deposition‐precipitation (DP) method. In this work, effect of charging sequence in DP process on catalyst structure and catalytic performance of Au/TS‐1 catalyst is first investigated. For different charging sequences, the compositions of Au complexes (e.g., [AuCl(OH)3]‐) and pore property of TS‐1 (i.e., with or without H2O pre‐filling micropores) could affect the transfer of Au complexes into the micropores, resulting in different Au locations and thus significantly different catalytic performance. Notably, when TS‐1 is first filled with H2O and then mixed with Au complexes, the reduced Au/TS‐1 catalyst could expose Au nanoparticles on the external surface of TS‐1 and show high stability. The results provide direct evidence showing that micropore blocking is the deactivation mechanism. Based on the results, a simple strategy to design highly stable Au/Ti‐based catalysts is developed. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-12T04:16:33.609959-05:
      DOI: 10.1002/aic.15313
       
  • DEM Study of Granular Flow Characteristics in the Active and Passive
           Regions of a Three‐dimensional Rotating Drum
    • Authors: Shiliang Yang; Jingwei Wang, Andy Cahyadi, Jia Wei Chew
      Abstract: Three‐dimensional modeling of the solid motion in a lab‐scale rotating drum has been conducted via the discrete element method (DEM). After validating the simulated results with available experimental data, the active‐passive interface was identified, following which particle‐scale information in these two regions, in particular the influences of fill level and rotating velocity, were obtained. The results demonstrate that: (i) the total number of particles in the passive region is three times that in the active, (ii) the transverse and axial velocities span a wider range in the active region, with the transverse values being greater, (iii) the collision force is much higher in the active region, with the greatest magnitudes in the y‐direction relative to that in the x‐ and z‐directions, (iv) particle displacements are generally lower and have a narrower distribution in the active region, (v) the local solid residence time (SRT) distribution profiles are similar axially in that the highest SRT magnitudes are at the center region of the bed, while the other parts of the bed have uniform SRT magnitudes. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-12T04:16:20.71735-05:0
      DOI: 10.1002/aic.15315
       
  • Theoretical Model for Multiple Breakup of Fluid Particles in Turbulent
           Flow Field
    • Authors: Kiyanoosh Razzaghi; Farhad Shahraki
      Abstract: Generalized phenomenological model, based on the theories of probability and isotropic turbulence, is developed for multiple breakup of fluid particles in turbulent flow field. The approach uses a series of successive binary breakup events occur at a time scale comparable to the colliding eddy turnover time. It was found that the use of energy density, instead of energy, will increase the predicted binary breakup rate which is usually underestimated by the existing models in the literature. Generalization of the binary breakup model for multiple fragmentations is performed by defining a “remaining energy function” for the colliding eddy which means the contribution of original eddy to the later breakup events. For ternary breakage, the model shows a reasonably good agreement with the experimental data. The quaternary fragmentation frequency, however, is of negligible importance at lower energy dissipation rates but its contribution to breakage fraction at higher energy dissipation rates becomes considerable. The results also show that ternary and quaternary breakups have a considerable 90% contribution to the overall fragmentation, while pentenary and further fragmentations are of lower importance at low energy dissipation rates. At higher levels of energy dissipation rate, fragmentations up to six daughter particles contribute to more than 95% of the overall fragmentations. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-12T04:15:57.123056-05:
      DOI: 10.1002/aic.15314
       
  • Tactical capacity planning for semiconductor manufacturing: MILP models
           and scalable distributed parallel algorithms
    • Abstract: A multi‐period stochastic mixed‐integer linear programming model is developed to address the tactical capacity planning of semiconductor manufacturing with considerations of complex routing of material flows, in‐process inventory, demand and capacity variability, multi‐site production, capacity utilization rate and downside risk management. Both planning level decisions (i.e., capacity allocation and customer service level decision) as well as operational level decisions (i.e., production, inventory and shipment decisions) can be simultaneously determined based on the two proposed multi‐objective optimization models. To address the huge number of scenarios needed to characterize the uncertainty and the large number of first‐stage integer variables in industrial scale applications, two novel scalable distributed parallel optimization algorithms are developed to mitigate the computational burden. The proposed mathematical models and algorithms are illustrated through two case studies from a major US semiconductor manufacturer. Results from these case studies provide key decision support for capacity expansion in semiconductor industry. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-10T18:21:44.980933-05:
      DOI: 10.1002/aic.15309
       
  • Investigation of Inhibitors Efficacy in Wax Deposition Mitigation Using a
           Laboratory Scale Flow Loop
    • Authors: Yuandao Chi; Nagu Daraboina, Cem Sarica
      Abstract: Statistically reliable wax inhibition experimental data was obtained by utilizing the newly built laboratory scale flow loop. The comb‐shaped inhibitors are found more effective in decreasing the thickness compared to the linear inhibitor under the same conditions. Moreover, this becomes more predominant as the chain length of inhibitors increases. Interestingly, even though all the inhibitors decreased the deposit thickness, the wax content increased significantly. Besides, the longer chain length (PI‐B) of the inhibitor results in a higher wax content. Since the combination of growth and aging influenced by the presence of inhibitor significantly, paraffin inhibition efficiency (PIE) based on the wax mass was proposed in order to quantitatively assess the inhibitors. Based on the PIE, PI‐B and PI‐C have more inhibition efficiency than PI‐A. Therefore, when selecting wax inhibitor, one should be aware about the strength of the deposit gel in addition to the reduction of the deposit mass. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-09T10:45:25.57602-05:0
      DOI: 10.1002/aic.15307
       
  • A Modified Thermodynamic Insight to Deliquescence of a
           Void‐Containing Nanocrystal Confirmed by MD Simulation
    • Authors: Hamed Akbarzadeh; Amir Nasser Shamkhali, Mohsen Abbaspour, Sirous Salemi, Azizeh Masoumi
      Abstract: Existence of voids in crystalline structures can affect their physical and chemical properties considerably. When the size of the crystal reaches to nanoscale, experimental determination of its void fraction is difficult. In this work, a molecular dynamics approach is introduced to find equilibrium void fractions of a simple cubic (CsCl) and fcc (KCl) nanocrystals by determination of their deliquescence relative humidity for different sizes and void fractions and extrapolation of the results to the bulk limit. In order to confirm the simulation results, the size dependency of deliquescence relative humidity to the nanoparticle size was studied thermodynamically by inclusion of size‐dependent density of water nanodroplet which leads to a simple homographic equation. This method proposes the equilibrium void percents of CsCl and KCl nanoparticles to be 10% and 15% respectively, which are obtained by extrapolation of the results to the bulk limit. The success of obtained Möbius function was also confirmed by fitting it to experimental data for deliquescence of NaCl nanoparticles which implies the importance of considering density of water nanodroplet as a size dependent quantity. Also, using the mentioned thermodynamic approach, void dependency of deliquescence for the nanoparticles was found to be as a quasi‐linear trend which is compatible with the simulation results. It is noticeable that the approach used this work for determination of equilibrium void fraction is only valid if the utilized force fields are accurate. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-09T10:45:22.146611-05:
      DOI: 10.1002/aic.15306
       
  • Using Functional Programming to recognize Named Structure in an
           Optimization Problem: Application to Pooling
    • Authors: Francesco Ceccon; Georgia Kouyialis, Ruth Misener
      Abstract: Branch‐and‐cut optimization solvers typically apply generic algorithms, e.g., cutting planes or primal heuristics, to expedite performance for many mathematical optimization problems. But solver software receives an input optimization problem as vectors of equations and constraints containing no structural information. This paper proposes automatically detecting named special structure using the pattern matching features of functional programming. Specifically, we deduce the industrially‐relevant nonconvex nonlinear Pooling Problem within a mixed‐integer nonlinear optimization problem and show that we can uncover pooling structure in optimization problems which are not pooling problems. Previous work has shown that preprocessing heuristics can find network structures; we show that we can additionally detect nonlinear pooling patterns. Finding named structures allows us to apply, to generic optimization problems, cutting planes or primal heuristics developed for the named structure. To demonstrate the recognition algorithm, we use the recognized structure to apply primal heuristics to a test set of standard pooling problems. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-09T10:41:11.559889-05:
      DOI: 10.1002/aic.15308
       
  • Early‐Stage Evaluation of Biorefinery Processing Pathways using
           Process Network Flux Analysis
    • Abstract: With growing interest in the biomass value chain, a multitude of reactions are proposed in literature for the conversion of biomass into a variety of biofuels. In the early design stage, data for a detailed design is scarce rendering an in‐depth analysis of all possibilities challenging. In this contribution, the screening methodology Process Network Flux Analysis (PNFA) is introduced assessing systematically the cost and energy performance of processing pathways. Based on the limited data available, a ranking of biorefinery pathways and a detection of bottlenecks is achieved by considering the reaction performance as well as the feasibility and energy demand of various separation strategies using thermodynamic sound shortcut models. PNFA is applied to a network of six gasoline biofuels from lignocellulosic biomass. While 2‐butanol is ruled out due to a lack in yield and selectivity, iso‐butanol and 2‐butanone are identified as economically promising fuels beyond ethanol. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-09T10:40:47.865457-05:
      DOI: 10.1002/aic.15305
       
  • TeCSMART: A Hierarchical Framework for Modeling and Analyzing Systemic
           Risk in Sociotechnical Systems
    • Authors: Venkat Venkatasubramanian; Zhizun Zhang
      Abstract: Recent systemic failures in different domains continue to remind us of the fragility of complex sociotechnical systems. Although these failures occurred in different domains, there are common failure mechanisms that often underlie such events. Hence, it is important to study these disasters from a unifying systems engineering perspective so that one can understand the commonalities as well as the differences to prevent or mitigate future events. We propose a new conceptual framework that systematically identifies the failure mechanisms in a sociotechnical system, across different domains. Our analysis includes multiple levels of a system, both social and technical, and identify the potential failure modes of equipment, humans, policies and institutions. With the aid of three major recent disasters, we demonstrate how this framework could help us compare systemic failures in different domains and identify the common failure mechanisms at all levels of the system. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-09T10:35:36.013876-05:
      DOI: 10.1002/aic.15302
       
  • Development of formation and growth models of CO2 hydrate film
    • Authors: Yutaka Abe; Xiao Ma, Takehiko Yanai, Kenji Yamane
      Abstract: This study aims to develop models to estimate the CO2 hydrate film formation and growth for different temperature and flow velocity conditions. First, the CO2 hydrate film thickness at the initial stage of its formation is experimentally measured under different temperature and flow velocity conditions using laser interferometry. Based on the results, the CO2 hydrate film thickness was found to decrease with increasing temperature and flow velocity. Next, the CO2 hydrate film formation model and growth model are developed, and the models are verified using the present experimental data. Finally, the long term growth of CO2 hydrate film thickness is estimated by the proposed growth model of CO2 hydrate film thickness. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-09T10:35:31.265428-05:
      DOI: 10.1002/aic.15304
       
  • Modeling bread baking with focus on overall deformation and local porosity
           evolution
    • Authors: Vincent Nicolas; Fernanda Vanin, Christophe Doursat, David Grenier, Tiphaine Lucas, Denis Flick
      Abstract: A two dimensional model of bread baking was developed including, for the first time, the dependence of dough viscosity on both temperature and moisture content, the carbon dioxide dissolved from liquid water together with gas generation from yeast at the beginning of baking and the shrinkage due to dough drying. Particular attention was paid to experimental validation of both overall and local variables such as local temperature, overall mass loss and local moisture content, overall CO2 released into the oven, and overall deformation and local expansion or shrinkage. Sensitivity studies on generation of carbon dioxide, gravity and shrinkage are presented to discuss their influences on bread geometry, porosity (reflecting the alveolar structure) and gas pressure. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-09T10:35:27.788138-05:
      DOI: 10.1002/aic.15301
       
  • A Superstructure Representation, Generation and Modeling Framework for
           Chemical Process Synthesis
    • Authors: WenZhao Wu; Carlos A. Henao, Christos T. Maravelias
      Abstract: We present a framework for the efficient representation, generation, and modeling of superstructures for process synthesis. First, we develop a new representation based on three basic elements: units, ports, and conditioning streams. Second, we present four rules based on “minimal” and “feasible” component sets for the generation of simple superstructures containing all feasible embedded processes. Third, in terms of modeling, we develop a modular approach, and formulate models for each basic element. We also present a canonical form of element models using input/output variables and constrained/free variables. The proposed methods provide a coherent framework for superstructure‐based process synthesis, allowing efficient model generation and modification. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-09T10:35:23.149802-05:
      DOI: 10.1002/aic.15300
       
  • Kinetics of the absorption of carbon dioxide into aqueous ammonia
           solutions
    • Abstract: Experiments were performed in a customized double stirred tank reactor (DSTR) to study the kinetics of CO2 absorption into NH3 solutions at concentrations ranging from 0.42 to 7.67 kmol·m−3 and temperatures between 273.15 and 293.15 K. The results show that the reactive absorption was 1st order with respect to CO2 but fractional order (1.6 – 1.8) with respect to ammonia. Experimental data can be satisfactorily interpreted by a termolecular mechanism using kNH3T=7.6089×108exp⁡(−4018.4T) and kH2OT=7.9161×107exp⁡(−4356.4T). This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-05T11:05:23.38303-05:0
      DOI: 10.1002/aic.15296
       
  • Effect of wetting difference across junction on dynamics of drops
           impacting on the junction of dual‐textured surfaces
    • Authors: V. Vaikuntanathan; D. Sivakumar
      Abstract: The present study reports the effect of wetting difference across the junction of smooth and groove‐textured portions of a dual‐textured surface on the various stages in the dynamics of liquid drops impacting on the junction. Two dual‐textured surfaces with substantially different wetting difference across their junction, Δθe = 65° and 25°, made of intrinsically hydrophilic stainless steel and intrinsically hydrophobic poly‐di‐methyl‐siloxane (PDMS) are considered. The effect of wetting difference across the junction is dominantly seen on the net drop drift velocity and subsequent bulk drop movement, ξ. ξ on the PDMS dual‐textured surface is less than that on the stainless dual‐textured surface due to the lower wetting difference across the junction of the former. The variation of ξ with impact velocity shows a contrasting trend between the stainless steel and PDMS dual‐textured surfaces due to the difference in critical impact velocity corresponding to drop impregnation on their groove‐textured portions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-05T10:25:27.345536-05:
      DOI: 10.1002/aic.15297
       
  • Carleman approximation based Quasi‐analytic Model Predictive Control
           for Nonlinear Systems
    • Authors: Yizhou Fang; Antonios Armaou
      Abstract: This manuscript aims at developing a nonlinear model predictive controller (NMPC) formulation based on Carleman approximation. It approximates the nonlinear dynamic constraints with polynomial ones through Taylor expansion. Then, it extends the state variables to higher orders following the Kronecker product rule and expresses the nonlinear dynamic constraints with an extended bilinear representation. With little loss of nonlinear information, the formulation enables analytical prediction of future states. It also analytically calculates the sensitivity of the cost function to the manipulated inputs to facilitate the search algorithm by serving as the gradient. We present a brief analysis of error accumulation caused by Carleman approximation and then improve the accuracy of the approach by resetting extended states periodically. The idea of efficient temporal discretization in control vector parameterization is embedded to improve the controller performance. The advantages are illustrated in two applications where we solve a tracking problem and a regulation problem. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-05T03:51:17.114831-05:
      DOI: 10.1002/aic.15298
       
  • Analytical solutions for species transport in a T‐sensor at low
           Peclet numbers
    • Authors: Arman Sadeghi
      Abstract: A 3D analytical solution is presented for the problem of mass transport in a T‐sensor by taking the axial diffusion effects into account. The solution methodology is based on an eigenfunction expansion of the solute concentration and enjoys the variational calculus for the solution of the associated eigenvalue problem. The method is capable of handling a mixed electroosmotic and pressure‐driven velocity profile and is executed assuming a rectangular channel cross‐section although it can be easily extended to more complex geometries. Two simplified models, one based on a uniform velocity profile, valid for the channel half height to Debye length ratios of above 100, and the other based on a depthwise averaging of the species concentration to be used for cases in which the channel width to height ratio is above 5 are also presented. As a part of the latter, expressions are derived for the Taylor dispersion coefficient of the mixed flow in a slit microconduit. The most interesting finding of the present study is that, when the diffusion mechanism significantly contributes to the axial movement of the species, the well‐known heterogeneous mass transport evolves into a nearly uniform pattern in the depthwise direction and the mixing length noticeably increases. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-05T03:51:13.329443-05:
      DOI: 10.1002/aic.15299
       
  • Determination of kinetics in batch cooling crystallization processes
           – A sequential parameter estimation approach
    • Abstract: A comprehensive methodology to carry out a sequential parameter estimation approach has been developed and validated for the determination of the kinetic parameters of the crystallization of a generic organic compound. The strength of the approach lies in the thorough design of isothermal experiments which facilitate the isolation and/or decoupling of the different crystallization phenomena. This methodology has been applied for the parameter estimation of primary and secondary nucleation, growth and agglomeration kinetics. The resulting crystallization model has been able to reproduce the quantiles d10, d50, and d90 of the volume‐based particle size distribution (PSD) of an independent seeded validation experiment with an error below 10 μm. The deviation in the prediction has been increased in the case of an independent unseeded experiment, although errors below the uncertainty of the measurement have been always obtained. The methodology here proposed is intended to be an efficient strategy for rapid modelling of batch crystallization processes. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-03T18:01:26.107955-05:
      DOI: 10.1002/aic.15295
       
  • High‐throughput methods using composition and structure spread
           libraries
    • Authors: John R. Kitchin; Andrew J. Gellman
      PubDate: 2016-05-03T09:46:50.432846-05:
      DOI: 10.1002/aic.15294
       
  • Liver function as an engineering system
    • Abstract: Process Systems Engineering has tackled a wide range of problems including manufacturing, the environment, and advanced materials design. Here we discuss how tools can be deployed to tackle medical problems which involve complex chemical transformations and spatial phenomena looking in particular at the liver system, the body's chemical factory. We show how an existing model has been developed to model distributed behaviour necessary to predict the behaviour of drugs for treating liver disease. The model has been used to predict the effects of suppression of de novo lipogenesis, stimulation of β‐oxidation and a combination of the two. A reduced model has also been used to explore the prediction of behaviour of hormones in the blood stream controlling glucose levels to ensure that levels are kept within safe bounds using interval methods. The predictions are made resulting from uncertainty in two key parameters with oscillating input resulting from regular feeding. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-30T00:11:22.56025-05:0
      DOI: 10.1002/aic.15292
       
  • Dye adsorption on zinc oxide nanoparticulates
           atomic‐layer‐deposited on polytetrafluoroethylene membranes
    • Authors: Sen Xiong; Liang Kong, Zhaoxiang Zhong, Yong Wang
      Abstract: In this work, zinc oxide (ZnO) is deposited onto porous polytetrafluoroethylene (PTFE) membranes via atomic layer deposition (ALD) and thus produced ZnO‐deposited PTFE membranes are used as adsorbents for the removal of dyes from aqueous solutions. We first examine the evolution of morphology, wettability, and crystallization of PTFE membranes with ZnO ALD. The presence of ZnO nanoparticulates significantly promotes the diffusion and contact of the aqueous solutions within the membrane on one hand, and endows the membrane a strong capability to adsorb dyes from the solutions on the other. Kinetic studies reveal that the adsorption of rhodamine B and acid orange 7 by the ZnO‐deposited PTFE membranes can be described by the pseudo‐second‐order and pseudo‐first‐order model, respectively, and the adsorption of both dyes follows the Langmuir isotherm. The used membranes can be easily regenerated by rinsing with ethanol and reused for multiple times without loss of removal efficiency. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-30T00:11:03.12383-05:0
      DOI: 10.1002/aic.15293
       
  • Mathematical Modeling of a Moving Bed Reactor for Post‐Combustion
           CO2 Capture
    • Authors: Hosoo Kim; David C. Miller, Srinivasarao Modekurti, Benjamin Omell, Debangsu Bhattacharyya, Stephen E. Zitney
      Abstract: A mathematical model for a moving bed reactor with embedded heat exchanger has been developed for application to solid sorbent‐based capture of carbon dioxide (CO2) from flue gas emitted by coal‐fired power plants. The reactor model is one‐dimensional, non‐isothermal, and pressure‐driven. The two‐phase (gas and solids) model includes rigorous kinetics and heat and mass transfer between the two phases. Flow characteristics of the gas and solids in the moving bed are obtained by analogy with correlations for fixed and fluidized bed systems. From the steady‐state perspective, this work presents the impact of key design variables that can be used for optimization. From the dynamic perspective, the paper shows transient profiles of key outputs that should be taken into account while designing an effective control system. In addition, the paper also presents performance of a model predictive controller for the moving bed regenerator under process constraints. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-29T04:26:43.901492-05:
      DOI: 10.1002/aic.15289
       
  • Engineering model for intumescent coating behavior in a pilot‐scale
           gas‐fired furnace
    • Abstract: In the event of a fire, intumescent fire protective coatings expand and form a thermally insulating char that protects the underlying substrate from heat and subsequent structural failure. The intumescence includes several rate phenomena, which have been investigated and quantified in the literature for several decades. However, various challenges still exist. The most important one concerns mathematical model validation under realistic exposure conditions and/or time scales. Another is the simplification of advanced models to overcome the often‐seen lack of a complete set of input and adjustable model parameters for a given coating, thereby providing models for industrial applications. In this work, these two challenges are addressed. Three experimental series, with an intumescent coating inside a 0.65 m3 gas‐fired furnace, heating up according to so‐called cellulosic fire conditions, were conducted and a very good repeatability was evident. The experiments were run for almost three hours, reaching a final gas temperature of about 1100 °C. Measurements include transient temperature developments inside the expanding char, at the steel substrate, and in the mineral wool insulation placed behind the substrate. A mathematical model, describing the intumescent coating behavior and temperatures in the furnace using a single overall reaction was developed and validated against experimental data. By including a decomposition front movement through the char, a good qualitative agreement was obtained. After further validation against experiments with other coating formulations, it has potential to become a practical engineering tool. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-29T04:26:16.060791-05:
      DOI: 10.1002/aic.15291
       
  • A Novel Multiscale Approach for Rapid Prediction of Phase Behaviors with
           Consideration of Molecular Conformations
    • Abstract: The conformational distribution of flexible molecules may have a significant influence on its physical properties and phase behaviors. While atomistic molecular simulations naturally include conformational changes, they are often computationally expensive and require separate simulations for each state condition. On the other hand, an equation of state (EOS) provides a rapid description for a variety of fluid properties over the whole phase space; however, because of the ignorance of molecular structure, it is difficult to obtain the interaction parameters from first‐principles. Here we propose a multiscale approach for simultaneous predictions of fluid properties and molecular conformational distribution. The PR+COSMOSAC EOS is used to provide the fugacity of chemical species in a mixture. The electrostatic and dispersion interactions in the EOS are determined from quantum‐mechanical solvation calculations and molecular dynamics simulations at a few state points. The conformational transitions are considered as chemical reactions with the equilibrium constant determined from ab initio G4 calculations. With all the EOS parameters obtained from molecular simulations at different scales, subsequent phase equilibrium predictions can be achieved within milliseconds. We validated this approach using 1,2‐dichloroethane (DCE), whose dipole moment varies from 6.34 × 10−30 Cm in the gauche‐form to 0 in the trans‐form. Our results show that this approach provides not only accurate predictions for the vapor‐liquid and liquid‐liquid equilibrium of DCE‐containing fluids but also quantitative descriptions of conformational distribution of DCE in these systems. This novel method can be very useful for the prediction of thermodynamic properties of fluids with explicit inclusion of molecular conformations. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-29T04:25:49.573535-05:
      DOI: 10.1002/aic.15290
       
  • Numerical Modeling of the Cooling Cycle and Associated Thermal Stresses in
           a Melt Explosive Charge
    • Authors: Warren Sanhye; Charles Dubois, Isabelle Laroche, Pierre Pelletier
      Abstract: A comprehensive simulation tool is developed to describe and optimize the cooling cycle in the melt‐casting of Composition B. It comprises a multiphysics approach tackling heat, mass and momentum transfers involved in the casting process. The highly non‐linear solidification step and development of thermal stresses are included. A V & V (Verification and Validation) approach was adopted whereby the model was verified against a benchmark problem and tested with a simple cylindrical geometry. Then, the approach was applied to a 105 mm caliber artillery shell and simulation results were in close agreement with experimental measurements. The model is equipped with a CZM function to account for adhesion between the solidified cast and the mold. During cooling, separation is possible and the size and location of gaps, depending on shrinkage and adhesion, are successfully emulated. The importance of controlled solidification is pointed out, especially regarding steep temperature gradients within the shell. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-26T10:05:47.240841-05:
      DOI: 10.1002/aic.15288
       
  • Covariance‐Based Hardware Selection Part IV: Solution Using the
           Generalized Benders Decomposition
    • Authors: Jin Zhang; Xiaoxi Wang, Donald J. Chmielewski
      Abstract: Recently the covariance based hardware selection problem has been shown to be of the Mixed Integer Convex Programming (MICP) class. While such a formulation provides a route to global optimality, use of the branch and bound search procedure has limited application to fairly small systems. The particular bottleneck is that during each iteration of the branch and bound search, a fairly slow Semi‐Definite Programming (SDP) problem must be solved to its global optimum. In this work, we illustrate that a simple reformulation of the MICP and subsequent application of the Generalized Benders Decomposition (GBD) algorithm will result in massive reductions in computational effort. While the resulting algorithm must solve multiple mixed integer linear programs, this increase in computational effort is significantly outweighed by the reduction in the number of SDP problems that must be solved. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-22T04:46:40.154406-05:
      DOI: 10.1002/aic.15285
       
  • A Novel Carbonized Polydopamine (C‐PDA) Adsorbent with High CO2
           Adsorption Capacity and Water Vapor Resistance
    • Authors: Shikai Xian; Feng Xu, Zhenxia Zhao, Qibin Xia, Jing Xiao, Yingwei Li, Haihui Wang, Zhong Li
      Abstract: Novel carbonized polydopamine adsorbents (C‐PDAs) with high surface area, high CO2 adsorption capacity and superior moisture resistance performance were prepared by one‐step synthesis method using polydopamine as carbon precursor at different KOH/C ratios, and then characterized. CO2 and water vapor adsorption performances of C‐PDAs were examined separately by static adsorption and fixed‐bed experiments. Results showed that BET area and pore volume of C‐PDA‐4 were up to 3342 m2/g and 2.01 cm3/g, respectively. Its CO2 adsorption capacity reached up to 30.5 mmol/g at 25 bar, much higher than many other adsorbents including MOFs. C‐PDAs prepared with high KOH/C ratios had low surface element concentrations of O and N resulting in low surface hydrophilic property. H2O(g) isotherm of C‐PDA was much lower than those on Mg‐MOF‐74, Cu‐BTC and MIL‐101(Cr). Fixed‐bed experiments showed that co‐presence of water vapor in feed stream with 30%RH had negligible impact on CO2 working capacity of C‐PDA. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-22T04:46:13.476988-05:
      DOI: 10.1002/aic.15283
       
  • A Hybrid Approach to Computing Electrostatic Forces in Fluidized Beds of
           Charged Particles
    • Authors: Jari Kolehmainen; Ali Ozel, Christopher M. Boyce, Sankaran Sundaresan
      Abstract: In particulate flow devices particles acquire electric charge through triboelectric charging, and resulting electrostatic forces can alter hydrodynamics. To capture this effect, the electrostatic force acting on individual particles in the device should be computed accurately. We present a hybrid approach to determine the electrostatic force, which finds the long‐range contribution to the electric field by solving the Poisson equation, estimates the short‐range contribution through truncated pairwise sum and adds a correction to avoid double counting. Euler‐Lagrange simulation of flows incorporating this hybrid approach reveals that bed height oscillations in small fluidized beds of particles with monopolar charge decreases with increasing charge level, which is related to lateral segregation of particles. A ring‐like layer of particles, reported in experimental studies, forms at modestly high charge levels. Beds with equal amounts of positively and negatively charged particles are fluidized in a manner similar to uncharged particles. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-22T04:45:46.633608-05:
      DOI: 10.1002/aic.15279
       
  • Characteristics and fouling propensity of polysaccharides in the presence
           of different monovalent ions
    • Authors: Xiang He; Fangang Meng, Anli Lin, Jiapeng Li, Chuyang Y. Tang
      Abstract: In this study the fouling behavior of alginate in the presence of monovalent ions (i.e., NaCl, KCl, CsCl, NaBr and NaI) was explored. Results showed that alginate tended to be less negatively charged in the presence of monovalent ions. The cation ion identity had a more substantial impact on the zeta potentials of alginate solution than the anion ion identity, which was likely due to preferential attraction between alginate and cation ion. Nevertheless, significantly increased particle size was observed for alginate in 150 mM CsCl, possibly arising from the specific interaction between alginate and Cs+. Membrane fouling was more severe for alginate in monovalent solutions, particularly at 150 mM ionic strength. The unified membrane fouling index was increased by cation and anion ions in the order of Na+ > K+ > Cs+ and Cl‐ > Br‐ > I‐, respectively. Nevertheless, the addition of monovalent ions could promote the fouling reversibility. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-20T04:01:56.672527-05:
      DOI: 10.1002/aic.15276
       
  • Drug release kinetics and mechanism from PLGA formulations
    • Abstract: The release kinetics of indomethacin (IND) and hydrochlorothiazide (HCT) from drug/PLGA formulations with different copolymer composition and molecular weight of PLGA were measured in vitro by using a rotating disk system (USP II). The release mechanism of IND and HCT from their PLGA formulations was analyzed using a chemical‐potential‐gradient model combined with the Perturbed‐Chain Statistical Associating Fluid Theory (PC‐SAFT). Furthermore, the release kinetics of IND and HCT from the PLGA formulations with different copolymer composition and molecular weight of PLGA were correlated and predicted in good accordance with the experimental data. It was found that the chemical‐potential‐gradient model combined with the PC‐SAFT helped to understand the drug release mechanism from the drug/PLGA formulations. It also well correlated and predicted the drug release kinetics as function of copolymer composition and molecular weight of PLGA as well as of drug type. It helps to save time and costs for determination of the long‐term drug release kinetics, especially for sustained drug release as obtained from the drug/PLGA formulations in this work. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-20T04:00:45.144879-05:
      DOI: 10.1002/aic.15282
       
  • Three‐component solids velocity measurements in the outlet section
           of a riser
    • Abstract: Coincident (simultaneous) three‐component particle velocity measurements performed using two Laser Doppler Anemometry (LDA) probes at the outlet section of a 9 m high cylindrical riser are for the first time presented for dilute flow conditions. Near the blinded extension of the T‐outlet a solids vortex is formed. Particle downflow along the riser wall opposite the outlet tube is observed, which is restricted to higher riser heights at higher gas flow rates. Increased velocity fluctuations are observed in the solids vortex and downflow region as well as at heights corresponding to the outlet tube. Contrary to the rest of the riser, in the downflow region time and ensemble velocity averages are not equal. Given the local bending of the streamlines, axial momentum transforms to radial and azimuthal momentum giving rise to the corresponding shear stresses. Turbulence intensity values indicate the edges of the downflow region. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-19T10:41:45.25215-05:0
      DOI: 10.1002/aic.15277
       
  • Effect of needle‐like crystal shape on measured particle size
           distributions
    • Authors: Ian de Albuquerque; David R. Ochsenbein, Manfred Morari, Marco Mazzotti
      Abstract: The effect crystal morphology has on measured particle size distributions (PSDs) is ex‐plored, with a focus on particles exhibiting a needle‐like habit. An idealized in silico study was performed, targeted at modeling the measurement principles of various par‐ticle sizing devices, namely laser diffraction, Coulter counter, focused beam reflectance measurement, a single and a dual projection imaging devices. The evolution of a crystal population is measured, allowing for an evaluation of the introduced biases. Further, the consequences of these biases are highlighted by demonstrating how the real growth mechanism may be incorrectly interpreted depending on the chosen particle sizing tech‐nique. It is found that techniques which utilize a one‐dimensional PSD are incapable of simultaneously describing the concentration profile and average length; in contrast, imaging techniques are able to reproduce both quantities. Finally, the dual projection imaging device is shown to be the only instrument to yield a nearly bias‐free measure‐ment. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-18T02:51:38.409777-05:
      DOI: 10.1002/aic.15270
       
  • Product design: Metal nanoparticle‐based conductive inkjet inks
    • Authors: Sze Kee Tam; Ka Yip Fung, Grace Sum Hang Poon, Ka Ming Ng
      Abstract: A systematic procedure that provides an efficient workflow for formulating conductive inks is developed. Qualitative product attributes of the inkjet ink are first identified and transformed into quantitative product specifications. Ingredients are then selected based on heuristics, mechanistic and empirical models to meet the product specifications. Printability checks based on theoretical criteria are used to ensure that stable droplets can in principle be formed and coalesced properly to form a printed line of ink. Then, the conductive ink is prepared and printed to evaluate the performance of the inkjet ink experimentally. An example of preparing a copper ink for inkjet printing is used to illustrate the systematic procedure. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-18T02:51:12.448224-05:
      DOI: 10.1002/aic.15271
       
  • A Review of the Operating Limits in Slot Die Coating Processes
    • Authors: Xiaoyu Ding; Jianhua Liu, Tequila A.L. Harris
      Abstract: Slot die coating is a pre‐metered process commonly used for producing thin and uniform films. It is an important film fabrication method for applications where precise coating is required. A major concern in slot die coating processes is how to determine the operating limits to set the appropriate range of operating parameters, including coating speed, flow rate, vacuum pressure, coating gap, liquid viscosity and surface tension, etc. Operating limits directly determine the effectiveness and efficiency of the process. In this paper, the current state of academic research on operating limits in slot die coating processes is reviewed. Specifically, the theories, mechanisms, and empirical conclusions related to the limits on vacuum pressure, the low‐flow limit, the limit of wet thickness for zero‐vacuum‐pressure cases, the limit of dynamic wetting failure, and the limits of coating speed for a specific flow rate are reviewed. The paper concludes with some recommendations for future work. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-06T10:36:27.394755-05:
      DOI: 10.1002/aic.15268
       
  • Fast Access to Core/Shell/Shell CdTe/CdSe/ZnO Quantum Dots via Magnetic
           Hyperthermia Method
    • Abstract: The intrinsic low quantum yield (QY) of type II core shell quantum dots (QDs) composes the limitation for these heterostructured nanomaterials to be used in practical application. Herein, magnetic hyperthermia method is employed to intensify reaction process and facilely synthesize CdTe/CdSe heterostructured quantum dots with improved optical performance for the first time. The QY of the type II QDs was increased to 49% by further growing an inert ZnO layer. The type I interface between CdSe and ZnO help confine electrons to the inner structure of the QDs, thus improving the QY. The successful preparation and performance enhancement of the CdTe/CdSe type II QDs via magnetic hyperthermia method demonstrates the great potential of this method the preparation of other materials. Besides, the red‐emission QDs are used as conversion materials in white light emitting diodes (LEDs) to reveal their promising application in practical illumination. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-31T11:21:33.445932-05:
      DOI: 10.1002/aic.15264
       
  • High‐performance polymer‐supported extractants with
           phosphonate ligands for scandium(III) separation
    • Authors: Hongmin Cui; Ji Chen, Hailian Li, Dan Zou, Yu Liu, Yuefeng Deng
      Abstract: As the market demand for scandium has grown, a great deal of interest has been generated in its recovery. To substantially simplify the process and provide a green alternative for scandium separation, novel polymer‐supported extractants containing di(2‐ethylhexyl) phosphonate and bis(2,4,4‐trimethylpentyl) phosphonate, [D201][DEHP] and [D201][C272] are proposed because they demonstrate improved adsorption capacity and selectivity toward scandium(III). Scandium(III) adsorption is significantly affected by the solution pH, with the maximum adsorption occurring at a pH of approximately 0.78. The batch adsorption data fit well with the Langmuir isotherm and pseudo‐second‐order kinetic models. A combination of the FTIR and XPS spectra suggest that the complexation of oxygen atoms in phosphate groups with scandium(III) is the predominant adsorption mechanism. Additionally, the two resins were used to recover scandium from leaching liquor of nickel laterite ore. [D201][DEHP] exhibits unusual selectivity for scandium and low competitive behavior with other metals, thus increasing its market potential. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-14T18:16:42.074411-05:
      DOI: 10.1002/aic.15236
       
  • Development of gas‐phase smb technology for light olefin/paraffin
           separations
    • Abstract: The separation of ethylene from ethane is particularly complex due to their similar physical properties. Cryogenic distillation is the most common technology employed for this separation and is one of the most expensive operations in industry, being the driving force for the ongoing research to find a more cost‐effective alternative. In the present work, a gas‐phase SMB bench unit was employed to produce polymer‐grade ethylene from ethane/ethylene mixtures, using binderless 13X zeolite beads as adsorbent, and propane as desorbent. The achieved performance parameters demonstrated the high efficiency of the current technology, since ethylene was obtained with a purity of 99.8%, a recovery of 99.8%, and a productivity of 59.7 kgC2H4·h−1·madsorbent−3. Considering the encouraging results obtained it is fair to say that the gas‐phase SMB is a competitive and strong candidate as alternative to the conventional process, especially when combined with enhanced performance adsorbents, such as binderless zeolites. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-14T18:15:49.111374-05:
      DOI: 10.1002/aic.15238
       
  • A Feedback Control Framework for Safe and Economically‐Optimal
           Operation of Nonlinear Processes
    • Authors: Fahad Albalawi; Anas Alanqar, Helen Durand, Panagiotis D. Christofides
      Abstract: Maintaining safe operation of chemical processes and meeting environmental constraints are issues of paramount importance in the area of process systems and control engineering, and are ideally achieved while maximizing economic profit. It has long been argued that process safety is fundamentally a process control problem, yet few research efforts have been directed towards integrating the rather disparate domains of process safety and process control. Economic model predictive control (EMPC) has attracted significant attention recently due to its ability to optimize process operation accounting directly for process economics considerations. However, there is very limited work on the problem of integrating safety considerations in EMPC to ensure simultaneous safe operation and maximization of process profit. Motivated by the above considerations, this work develops three EMPC schemes that adjust in real‐time the size of the safety sets in which the process state should reside in order to ensure safe process operation and feedback control of the process state while optimizing economics via time‐varying process operation. Recursive feasibility and closed‐loop stability are established for a sufficiently small EMPC sampling period. The proposed schemes, which effectively integrate feedback control, process economics and safety considerations, are demonstrated with a chemical process example. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-06T06:50:37.917598-05:
      DOI: 10.1002/aic.15222
       
  • On the Relation Between Flexibility Analysis and Robust Optimization for
           Linear Systems
    • Authors: Qi Zhang; Ricardo M. Lima, Ignacio E. Grossmann
      Abstract: Flexibility analysis and robust optimization are two approaches to solving optimization problems under uncertainty that share some fundamental concepts, such as the use of polyhedral uncertainty sets and the worst‐case approach to guarantee feasibility. The connection between these two approaches has not been sufficiently acknowledged and examined in the literature. In this context, the contributions of this work are fourfold: (1) a comparison between flexibility analysis and robust optimization from a historical perspective is presented; (2) for linear systems, new formulations for the three classical flexibility analysis problems—flexibility test, flexibility index, and design under uncertainty—based on duality theory and the affinely adjustable robust optimization (AARO) approach are proposed; (3) the AARO approach is shown to be generally more restrictive such that it may lead to overly conservative solutions; (4) numerical examples show the improved computational performance from the proposed formulations compared to the traditional flexibility analysis models. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-03T19:58:24.052907-05:
      DOI: 10.1002/aic.15221
       
  • Evolution of functional polymer colloids for coatings and other
           applications
    • Authors: John Klier; James Bohling, Melinda Keefe
      PubDate: 2016-02-25T03:25:19.558113-05:
      DOI: 10.1002/aic.15211
       
  • Issue information ‐ table of contents
    • Pages: 2237 - 2237
      PubDate: 2016-06-02T09:25:33.097488-05:
      DOI: 10.1002/aic.14992
       
  • Stability of an inclined, pneumatically‐transported system of
           particles
    • Authors: Kevin Mandich; Robert J. Cattolica
      Pages: 2248 - 2258
      Abstract: A linear stability analysis is performed on the base‐state solution describing a pneumatically‐transported system inclined at an angle θ. One of two modes was found to be dominant, depending on the tilting angle: a low‐shear mode whose voidage eigenmode remains nearly symmetric from 0°  θc, marked by significant asymmetry throughout the domain and a high level of shear inside the thin regions adjacent to the walls. The critical angle θc increases with the amount of momentum and energy lost to particle–wall friction and collisions, respectively. The time‐evolution of the latter mode, superimposed onto the base‐state solution, reveals an alternating train of dense and dilute regions near the top of the domain, which agrees qualitatively with the development and propagation of bubbles in inclined systems observed in experiment. An analytic solution corresponding to a vertical system with a uniform base state was also derived to identify the instability mechanisms responsible for a class of non‐oscillatory transverse waves which exist in both vertical and tilted particle systems. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2248–2258, 2016
      PubDate: 2016-03-27T21:10:47.750201-05:
      DOI: 10.1002/aic.15207
       
  • An adhesive CFD‐DEM model for simulating nanoparticle agglomerate
           fluidization
    • Authors: Daoyin Liu; Berend G. M. van Wachem, Robert F. Mudde, Xiaoping Chen, J. Ruud van Ommen
      Pages: 2259 - 2270
      Abstract: Nanoparticles are fluidized as agglomerates with hierarchical fractal structures. In this study, we model nanoparticle fluidization by assuming the simple agglomerates as the discrete element in an adhesive (Computational Fluid Dynamics—Discrete Element Modelling) CFD‐DEM model. The simple agglomerates, which are the building blocks of the larger complex agglomerates, are represented by cohesive and plastic particles. It is shown that both the particle contact model and drag force interaction in the conventional CFD‐DEM model need modification for properly simulating a fluidized bed of nanoparticle agglomerates. The model is tested for different cases, including the normal impact, angle of repose (AOR), and fluidization of nanoparticle agglomerates, represented by the particles with the equivalent material properties. It shows that increasing the particle adhesion increases the critical stick velocity, angle of repose, and leads from uniform fluidization to defluidization. The particle adhesion, bulk properties, and fluidization can be linked to each other by the current adhesive CFD‐DEM model. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2259–2270, 2016
      PubDate: 2016-03-27T21:01:02.130999-05:
      DOI: 10.1002/aic.15219
       
  • Numerical studies of the effects of fines on fluidization
    • Authors: Yile Gu; Ali Ozel, Sankaran Sundaresan
      Pages: 2271 - 2281
      Abstract: Euler‐Lagrange simulations of fluidized beds of Geldart Group A particles containing different levels of fines are performed in periodic domains with various domain‐averaged solid volume fractions. Bubble‐like voids readily form when no fines are added. Introducing fines does not reduce bubble sizes if van der Waals force between particles is not accounted for. In contrast, the addition of van der Waals force produces significant changes. With no fines, bubbles are found to be suppressed at sufficiently high solid volume fractions, corresponding to the expanded bed regime for Group A particles. With the addition of fines, bubbles can be suppressed at lower solid volume fractions. With more fines added, bubbles can be suppressed at even lower solid volume fractions. When bubbles are suppressed, the system is found to be in a stable solid‐like regime. In this regime, forces on each particle are balanced, and the particle velocity fluctuations are dampened. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2271–2281, 2016
      PubDate: 2016-03-20T17:00:53.271213-05:
      DOI: 10.1002/aic.15229
       
  • Multi‐period planning, design, and strategic models for
           long‐term, quality‐sensitive shale gas development
    • Authors: Markus G. Drouven; Ignacio E. Grossmann
      Pages: 2296 - 2323
      Abstract: In this work we address the long‐term, quality‐sensitive shale gas development problem. This problem involves planning, design, and strategic decisions such as where, when, and how many shale gas wells to drill, where to lay out gathering pipelines, as well as which delivery agreements to arrange. Our objective is to use computational models to identify the most profitable shale gas development strategies. For this purpose we propose a large‐scale, nonconvex, mixed‐integer nonlinear programming model. We rely on generalized disjunctive programming to systematically derive the building blocks of this model. Based on a tailor‐designed solution strategy we identify near‐global solutions to the resulting large‐scale problems. Finally, we apply the proposed modeling framework to two case studies based on real data to quantify the value of optimization models for shale gas development. Our results suggest that the proposed models can increase upstream operators’ profitability by several million U.S. dollars. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2296–2323, 2016
      PubDate: 2016-03-25T13:11:22.589757-05:
      DOI: 10.1002/aic.15174
       
  • Process design methodology for energy‐efficient processes operating
           below and across ambient temperature
    • Authors: Danahe Marmolejo Correa; Truls Gundersen
      Pages: 2324 - 2340
      Abstract: This article presents a targeting and design methodology that can be implemented for any process where pressure‐based exergy, also known as mechanical exergy, has an important contribution to the total exergy conversion and transfer. However, in this article it is applied to processes that operate at sub‐ambient conditions, or processes where the ambient conditions are crossed. Exergy efficiencies, new Exergetic Composite Curves, Cascades, and Extended Grid Diagrams are tools that had to be implemented, improved, or invented, to develop a methodology with considerable potential for energy‐efficient process design. The appropriate placement (correct integration) of compressors and expanders in heat exchanger networks is also analyzed to minimize the number of units. An example is used to demonstrate the methodology, where several simplifying assumptions are made to facilitate understanding and to explain the design method. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2324–2340, 2016
      PubDate: 2016-03-20T16:40:56.491723-05:
      DOI: 10.1002/aic.15200
       
  • Advanced control strategies for the multicolumn countercurrent solvent
           gradient purification process
    • Pages: 2341 - 2357
      Abstract: The multicolumn countercurrent solvent gradient purification process (MCSGP) is a semicontinuous, chromatographic separation process used in the production of monoclonal antibodies) . The process is characterized by high model complexity and periodicity that challenge the development of control strategies, necessary for feasible and efficient operation and essential toward continuous production. A novel approach for the development of control policies for the MCSGP process, which enables efficient continuous process control is presented. Based on a high fidelity model, the recently presented PAROC framework and software platform that allows seamless design and in‐silico validation of advanced controllers for complex systems are followed. The controller presented in this work is successfully tested against disturbances and is shown to efficiently capture the process periodic nature. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2341–2357, 2016
      PubDate: 2016-03-06T17:27:50.908573-05:
      DOI: 10.1002/aic.15203
       
  • An iterative two‐step sequential phase partition (ITSPP) method for
           batch process modeling and online monitoring
    • Authors: Yan Qin; Chunhui Zhao, Furong Gao
      Pages: 2358 - 2373
      Abstract: Operating at different manufacturing steps, multiphase modeling and analysis of the batch process are advantageous to improving monitoring performance and understanding manufacturing processes. Although many phase partition algorithms have been proposed, they have some disadvantages and cause problems: (1) time sequence disorder, which requires elaborate post‐treatments; (2) a lack of quantitative index to indicate transition patterns; and (3) tunable parameters that cannot be quantitatively determined. To effectively overcome these problems, an iterative two‐step sequential phase partition algorithm is proposed in the present work. In the first step, initial phase partition results are obtained by checking changes of the control limit of squared prediction error. Sequentially, the fast search and find of density peaks clustering algorithm is employed to adjust the degradation degree and update the phase partition results. These two steps are iteratively executed until a proper degradation degree is found for the first phase. Then, the remaining phases are processed one by one using the same procedure. Moreover, a statistical index is quantitatively defined based on density and distance analysis to judge whether a process has transitions, and when the transition regions begin and end. In this way, the phases and transition patterns are quantitatively determined without ambiguity from the perspective of monitoring performance. The effectiveness of the proposed method is illustrated by a numerical example and a typical industrial case. Several typical phase partition algorithms are also employed for comprehensive comparisons with the proposed method. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2358–2373, 2016
      PubDate: 2016-02-29T11:39:32.202986-05:
      DOI: 10.1002/aic.15205
       
  • Distributional uncertainty analysis and robust optimization in spatially
           heterogeneous multiscale process systems
    • Pages: 2374 - 2390
      Abstract: Multiscale models have been developed to simulate the behavior of spatially‐heterogeneous porous catalytic flow reactors, i.e., multiscale reactors whose concentrations are spatially‐dependent. While such a model provides an adequate representation of the catalytic reactor, model‐plant mismatch can significantly affect the reactor's performance in control and optimization applications. In this work, power series expansion (PSE) is applied to efficiently propagate parametric uncertainty throughout the spatial domain of a heterogeneous multiscale catalytic reactor model. The PSE‐based uncertainty analysis is used to evaluate and compare the effects of uncertainty in kinetic parameters on the chemical species concentrations throughout the length of the reactor. These analyses reveal that uncertainty in the kinetic parameters and in the catalyst pore radius have a substantial effect on the reactor performance. The application of the uncertainty quantification methodology is illustrated through a robust optimization formulation that aims to maximize productivity in the presence of uncertainty in the parameters. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2374–2390, 2016
      PubDate: 2016-03-15T06:11:33.679054-05:
      DOI: 10.1002/aic.15215
       
  • Pd@C3N4 nanocatalyst for highly efficient hydrogen storage system based on
           potassium bicarbonate/formate
    • Authors: Xianzhao Shao; Jinming Xu, Yanqiang Huang, Xiong Su, Hongmin Duan, Xiaodong Wang, Tao Zhang
      Pages: 2410 - 2418
      Abstract: Formate/bicarbonate system has several desirable properties such as noncorrosive and nonirritating nature, as well as facile handling, which make it an attractive candidate for a safe, reversible hydrogen storage material. Herein, Pd nanoparticles supported on mesoporous graphitic carbon nitride (mpg‐C3N4) for formate‐based reversible hydrogen storage is reported. The as‐developed Pd/mpg‐C3N4 material was shown to be a superior catalyst for the hydrogenation of high concentrations of bicarbonate to formate under mild conditions. The effects of reaction temperature, H2 pressure, and bicarbonate concentration on the hydrogenation of bicarbonate to formate were investigated. The catalytic performance remained steady with high activity up to six hydrogenation cycles. The interaction between mpg‐C3N4 and Pd nanoparticles and the concerted effects of the nitrogen species located at mpg‐C3N4 and bicarbonate played a synergetic role in the enhancement of the performance of the catalyst for hydrogenation. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2410–2418, 2016
      PubDate: 2016-03-22T14:25:46.198279-05:
      DOI: 10.1002/aic.15218
       
  • Model‐based analysis of chemical‐looping combustion
           experiments. Part I: Structural identifiability of kinetic models for NiO
           reduction
    • Authors: Lu Han; Zhiquan Zhou, George M. Bollas
      Pages: 2419 - 2431
      Abstract: To guide the design of chemical‐looping combustion (CLC) systems, the use of accurate models is crucial. The reduction kinetics between NiO and CH4 is uncertain, in regards to the most suitable kinetic mechanism and reaction network. A framework for structural identifiability analysis is developed and applied to evaluate the candidate kinetic models for the NiO‐CH4 reaction. The identifiability of kinetic parameters of different model structures is analyzed and compared. Models that lack structural identifiability of their kinetic parameters are rejected in the analysis. From a total of 160 possible candidate models, 4 kinetic models are found to be identifiable with respect to their kinetic parameters and distinguishable from different model structures. This structural identifiability analysis paves the way for model‐based design of experiments, which is the subject of Part II of this work. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2419–2431, 2016
      PubDate: 2016-03-20T16:55:51.512931-05:
      DOI: 10.1002/aic.15225
       
  • Model‐based analysis of chemical‐looping combustion
           experiments. Part II: Optimal design of CH4‐NiO reduction
           experiments
    • Authors: Lu Han; Zhiquan Zhou, George M. Bollas
      Pages: 2432 - 2446
      Abstract: There is significant controversy in the reduction kinetics of chemical‐looping combustion (CLC) between NiO and CH4. We propose an application of a model‐based framework to improve the quality of CLC experiments with respect to model discrimination and parameter estimation. First, optimal experiments are designed and executed to reject inadequate models and to determine a true model structure for the reaction kinetics of the CH4‐NiO system. Then, kinetics with statistical significance is estimated from experiments aimed at reducing parameter uncertainty. To maximize the observability of the NiO reduction reactions, fixed bed experiments should exhibit a peak separation of the concentration profiles, an initial high methane slip, and low overall CO2 selectivity. Several case studies are presented to check the adequacy of the recommended model and evaluate its predictive ability and extrapolation capabilities. The model resulting from this work is validated and suitable for application in process design and optimization. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2432–2446, 2016
      PubDate: 2016-03-27T21:11:28.229595-05:
      DOI: 10.1002/aic.15242
       
  • Ethanol perm‐selective B‐ZSM‐5 zeolite membranes from
           dilute solutions
    • Authors: Lijun Chai; Jianhua Yang, Jinming Lu, Dehong Yin, Yan Zhang, Jinqu Wang
      Pages: 2447 - 2458
      Abstract: Boron‐substituted MFI (B‐ZSM‐5) zeolite membranes with high pervaporation (PV) performance were prepared onto seeded inexpensive macroporous α‐Al2O3 supports from dilute solution and explored for the separation of ethanol/water mixtures by PV. The effects of several parameters on microstructures and PV performance of the B‐ZSM‐5 membranes were examined systematically, including the seed size, synthesis temperature, crystallization time, B/Si ratio, H2O/SiO2 ratio and silica source. A continuous and compact B‐ZSM‐5 membrane was fabricated from solution containing 1 tetraethyl orthosilicate/0.2 tetrapropylammonium hydroxide/0.06 boric acid/600 H2O at 448 K for 24 h, showing a separation factor of 55 and a flux of 2.6 kg/m2 h along with high reproducibility for a 5 wt % ethanol/water mixture at 333 K. It was demonstrated that the incorporation of boron into mobile five (MFI) structure could increase the hydrophobicity of B‐ZSM‐5 membrane evidenced by the improved contact angle and amount of the adsorbed ethanol, and thus enhance the PV property for ethanol/water mixtures. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2447–2458, 2016
      PubDate: 2016-03-11T21:45:52.123581-05:
      DOI: 10.1002/aic.15214
       
  • New insights into sodium alginate fouling of ceramic hollow fiber
           membranes by NMR imaging
    • Pages: 2459 - 2467
      Abstract: Ceramic hollow fiber membranes are investigated with respect to the fouling behavior. Constant pressure dead‐end filtration experiments have been performed using alginate as model substance for extracellular polymeric substances. In addition to the evaluation of the filtration data using conventional cake filtration model, nuclear magnetic resonance imaging (MRI) was used to elucidate the influence of Ca2+ on the fouling layer structure for alginate filtration within ceramic hollow fiber membranes. To visualize the alginate layers inside the opaque ceramic hollow fiber membranes by means of MRI, specific contrast agents were applied. Supplementary to multi slice multi echo imaging, flow velocity measurements were performed to gain more insight into the hydrodynamics in the fouled membranes. MRI reveals the structure of the alginate layers with the finding that the addition of Ca2+ to the alginate feed solution promotes the formation of a dense alginate gel layer on the membrane's surface. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2459–2467, 2016
      PubDate: 2016-03-20T16:50:47.546491-05:
      DOI: 10.1002/aic.15226
       
  • Mass transfer simulation on pervaporation dehydration of ethanol through
           hollow fiber NaA zeolite membranes
    • Authors: Peng Ye; Yuting Zhang, Haifeng Wu, Xuehong Gu
      Pages: 2468 - 2478
      Abstract: A multi‐layer series‐resistance mass transfer model was developed to simulate mass transfer behaviors of water/ethanol mixture through hollow fiber NaA zeolite membranes. The mass transfer through zeolite layer was described by Maxwell‐Stefan mechanism based on adsorption and diffusion parameters obtained from molecular simulation. The mass transfer through asymmetric hollow fiber support was described by dusty gas model involving Knudsen diffusion and viscous flow. It was found that the sponge‐like layer of support besides of zeolite layer made an important contribution to overall membrane transfer resistance while the finger‐like layer had less effect. When permeate pressure shifted from 0.2 to 7.5 kPa, the mass transfer resistance contribution of sponge‐like layer varied from 27.1 to 17.8%. Effects of microstructure parameters of support on mass transfer through membrane were investigated extensively. Large pore size and thin thickness for sponge‐like layer of support were beneficial to improve water permeation flux. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2468–2478, 2016
      PubDate: 2016-03-20T16:45:50.690451-05:
      DOI: 10.1002/aic.15227
       
  • Permeation of oil‐in‐water emulsions through coalescing
           
    • Authors: Yasushi Mino; Yusuke Kagawa, Hideto Matsuyama, Toru Ishigami
      Pages: 2525 - 2532
      Abstract: The permeation of an oil‐in‐water emulsion through a coalescing filter is studied numerically. Our simulation model is based on the phase‐field model owing to its simple description of the wetting behavior of oil droplets on versatile surfaces. To realize two‐dimensional (2D) simulations of the coalescing processes, we construct a 2D filter model which describes the cross‐sectional structure of a fibrous filter in a simple manner. We investigate the effects of wettability, permeation flux, and fiber diameter on coalescing behavior. Oil droplets attach to the fibers and coalesce with each other, forming a bridging structure between fibers which promotes droplet coalescence unless the bridging structure blocks the entire flow path. This coalescence‐promoting effect of the bridging structure is observed under conditions where the fluid velocity inside a pore is relatively large. We demonstrate that our numerical model provides useful information to effectively design a coalescing filter and process. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2525–2532, 2016
      PubDate: 2016-02-29T11:40:57.159494-05:
      DOI: 10.1002/aic.15206
       
  • Wetting kinetics of polymer solutions and force‐based contact angles
    • Pages: 2533 - 2541
      Abstract: The effect of the shear thinning behavior and elasticity of polymer solutions on the dynamic contact angles are investigated. Under dynamic conditions, the contact angle of a liquid on a solid surface changes significantly with the substrate velocity from its equilibrium value. The dynamic contact angles for polyethylene oxide (PEO) solutions of two molecular weights 3 × 105 and 4 × 106 have been measured using a polyethylene terephthalate (PET) plate. The three‐parameter Ellis model to fit the rheological data to obtain shear thinning power n, characteristic shear stress, and the zero‐shear viscosity is used. The theory indicates that dynamic contact angles follow power law in this instance instead of showing Newtonian behavior with zero‐shear viscosity when the shear thinning effects are considered. The elastic effect becomes important at larger polymer concentrations that reduces the dependence on capillary number, that is, reduces n keeping with the experiments. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2533–2541, 2016
      PubDate: 2016-03-11T21:41:24.490689-05:
      DOI: 10.1002/aic.15213
       
  • Study on the transient interfacial tension in a microfluidic droplet
           formation coupling interphase mass transfer process
    • Authors: Wenjie Lan; Che Wang, Xuqiang Guo, Shaowei Li, Guangsheng Luo
      Pages: 2542 - 2549
      Abstract: In two‐phase dispersion coupling interphase mass transfer process, the variation of interfacial tension is an important factor affecting the dispersion. In this study, we described a microfluidic method for the determination of the transient interfacial tension (TIFT). The method has the advantage of determining TIFT during the whole droplet formation process, rather than only at the rupture moment as reported in previous studies. The TIFTs of several systems were determined. In certain systems, it has been found that the droplet size decreased with the increase of the dispersed phase flow rate, which is obviously different from the constant interfacial tension system. It has also been found that TIFT was mainly affected by two‐phase flow rates, solute type and concentration, and droplet size. A semiempirical equation was finally established to predict TIFT. It has the potential to be used in a variety of industrial equipment with dispersion–mass transfer coupling process. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2542–2549, 2016
      PubDate: 2016-03-18T10:50:52.072239-05:
      DOI: 10.1002/aic.15217
       
  • Wax deposition modeling of oil/gas stratified smooth pipe flow
    • Authors: Jimiao Duan; Huishu Liu, Jinfa Guan, Weixing Hua, Guangwei Jiao, Jing Gong
      Pages: 2550 - 2562
      Abstract: Wax deposition modeling is complicated under oil/gas two‐phase pipe flow and therefore remains poorly understood. One‐dimensional empirical heat and mass transfer correlations are unreliably for deposition modeling in stratified flow, due to non‐uniform deposit across the pipe circumference. A mathematical model has been developed to predict the deposit thickness and the wax fraction of deposit in oil/gas stratified pipe flow using a unidirectional flow analysis of non‐isothermal hydrodynamics and heat/mass transfer. The predictions for wax deposition are found to compare satisfactorily with experimental data with three different oils for single phase and oil/gas stratified pipe flow. In particular, the reason that the deposit forming a crescent shape at the cross section of pipe observed in different experiments is revealed, based on the non‐uniform circumferential distributions of two most important parameters for the wax deposition, diffusivity at oil–deposit interface, and the solubility gradient at the oil–deposit interface at different time. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2550–2562, 2016
      PubDate: 2016-03-22T14:30:55.697216-05:
      DOI: 10.1002/aic.15223
       
  • Strain mode of general flow: Characterization and implications for flow
           pattern structures
    • Authors: Yasuya Nakayama; Toshihisa Kajiwara, Tatsunori Masaki
      Pages: 2563 - 2569
      Abstract: Understanding the mixing capability of mixing devices based on their geometric shape is an important issue both for predicting mixing processes and for designing new mixers. The flow patterns in mixers are directly connected with the modes of the local strain rate, which is generally a combination of elongational flow and planar shear flow. We develop a measure to characterize the modes of the strain rate for general flow occurring in mixers. The spatial distribution of the volumetric strain rate (or non‐planar strain rate) in connection with the flow pattern plays an essential role in understanding distributive mixing. With our measure, flows with different types of screw elements in a twin‐screw extruder are numerically analyzed. The difference in flow pattern structure between conveying screws and kneading disks is successfully characterized by the distribution of the volumetric strain rate. The results suggest that the distribution of the strain rate mode offers an essential and convenient way for characterization of the relation between flow pattern structure and the mixer geometry. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2563–2569, 2016
      PubDate: 2016-03-17T10:51:13.104259-05:
      DOI: 10.1002/aic.15228
       
  • Dynamic delayed detached eddy simulation of a multi‐inlet vortex
           reactor
    • Authors: Zhenping Liu; Alberto Passalacqua, Michael G. Olsen, Rodney O. Fox, James C. Hill
      Pages: 2570 - 2578
      Abstract: The multi‐inlet vortex reactor (MIVR) is used for flash nanoprecipitation to manufacture functional nanoparticles. A validated computational fluid dynamics model is needed for the design, scale‐up, and optimization of the MIVR. Unfortunately, available Reynolds‐averaged Navier‐Stokes methods are unable to accurately model the highly swirling flow in the MIVR. Large‐eddy simulations (LES) are also problematic, as excessively fine grids are required to accurately model this flow. These dilemmas led to the application of the dynamic delayed detached eddy simulation (DDES) method to the MIVR. In the dynamic DDES model, the eddy viscosity has a form similar to the Smagorinsky sub‐grid viscosity in LES, which allows the implementation of a dynamic procedure to determine its model coefficient. Simulation results using the dynamic DDES model are found to match well with experimental data in terms of mean velocity and turbulence intensity, suggesting that the dynamic DDES model is a good option for modeling the turbulent swirling flow in the MIVR. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2570–2578, 2016
      PubDate: 2016-03-23T21:11:00.555583-05:
      DOI: 10.1002/aic.15230
       
  • Heat transfer coefficient for condensation of steam on freely formed
           falling liquid jets
    • Pages: 2579 - 2584
      Abstract: This article presents the research results of direct contact condensation of steam on freely formed falling liquid jets. After the comparison of experimental data and open literature correlations it was concluded that published correlations does not provide accurate coverage of experimental data. A new correlation was established in the following form Nu=1980⋅[Re⁡L1.175⋅(μLμW)1.175+17740]⋅WeG0.86⋅FrL0.23⋅KuW1.14WeW0.98⋅Pr⁡W1.8⋅                ⋅(ρLρW)0.97⋅(σLσW)−0.12⋅φ(HLGdh) © 2016 American Institute of Chemical Engineers AIChE J, 62: 2579–2584, 2016
      PubDate: 2016-03-27T21:05:46.133485-05:
      DOI: 10.1002/aic.15233
       
 
 
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