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  Subjects -> ENGINEERING (Total: 2266 journals)
    - CHEMICAL ENGINEERING (190 journals)
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    - ENGINEERING (1195 journals)
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    - MECHANICAL ENGINEERING (89 journals)

ENGINEERING (1195 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Full-text available via subscription   (Followers: 5)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 216)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 1)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 10)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 4)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 6)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 18)
Advances in Artificial Neural Systems     Open Access   (Followers: 3)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 14)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 18)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 13)
Advances in Polymer Science     Hybrid Journal   (Followers: 40)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 35)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 29)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 5)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 6)
Applied Clay Science     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
Applied Nanoscience     Open Access   (Followers: 7)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 4)
Applied Sciences     Open Access   (Followers: 3)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 8)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 2)
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 7)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 7)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
Batteries     Open Access   (Followers: 3)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 3)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 9)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 1)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Full-text available via subscription   (Followers: 13)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 40)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 7)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 5)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 4)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 4)
Coatings     Open Access   (Followers: 2)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 23)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 252)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 177)
Composites Part B : Engineering     Hybrid Journal   (Followers: 223)
Composites Science and Technology     Hybrid Journal   (Followers: 164)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 12)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 25)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 8)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 25)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 7)
Control Engineering Practice     Hybrid Journal   (Followers: 40)
Control Theory and Informatics     Open Access   (Followers: 7)
Corrosion Science     Hybrid Journal   (Followers: 24)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)

        1 2 3 4 5 6 | Last

Journal Cover AIChE Journal
  [SJR: 1.122]   [H-I: 120]   [29 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  [1589 journals]
  • FeOx Supported Single-Atom Pd Bifunctional Catalyst for Water Gas Shift
    • Authors: Xiucheng Sun; Jian Lin, Yanliang Zhou, Lin Li, Yang Su, Xiaodong Wang, Tao Zhang
      Abstract: Water gas shift (WGS) reaction on supported noble metal catalysts is an essential process for upgrading hydrogen source industrially. Here a series of Pd/FeOx catalysts were detected for this reaction with Pd/Al2O3 as reference. It was found that Pd/FeOx exhibited higher CO conversion than Pd/Al2O3 with a good stability even in the presence of CO2 and H2. Along the loading decreasing, the turnover frequency of exposed Pd atoms increased with the dispersion from subnanometer (∼1 nm) to single-atoms. Various characterizations suggested that Pd single-atoms greatly enhanced the reducibility of FeOx and facilitated the formation of oxygen vacancies, which served as sites to promote the dissociation of H2O to form H2 and atomic O. The atomic O was ready to react with the linear adsorbed CO species on Pd single-atom sites through a redox mechanism, which resulted in low activation energy of ∼30 kJ/mol. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T11:20:40.445778-05:
      DOI: 10.1002/aic.15759
  • Growth and Breakup of a Wet Agglomerate in a Dry Gas-Solid Fluidized Bed
    • Authors: C. M. Boyce; A. Ozel, J. Kolehmainen, C.A. McKnight, M. Wormsbecker, S. Sundaresan
      Abstract: Using CFD-DEM simulations, a wet agglomerate of particles was placed in a void region of a dry vigorously fluidized bed to understand how wet agglomerates grow or breakup and how liquid spreads when agglomerates interact with dry fluidized particles. In the CFD-DEM model, cohesive and viscous forces arising from liquid bridges between particles were modeled, as well as a finite rate of liquid bridge filling. The liquid properties were varied between different simulations to vary Bond number (surface tension forces/gravitational forces) and Capillary number (viscous forces/surface tension forces) in the system. Resulting agglomerate behavior was divided into regimes of (i) the agglomerate breaking up, (ii) the agglomerate retaining its initial form, but not growing and (iii) the agglomerate retaining its initial form and growing. Regimes were mapped based on Bo and Ca. Implications of agglomerate behavior on spreading of liquid to initially dry particles were investigated.This paper identifies a new way to map agglomerate growth and breakup behavior based on Bo and Ca. In modeling both liquid forces and a finite rate of liquid transfer, it identifies the complex influence viscosity has on agglomeration by strengthening liquid bridges while slowing their formation. Viewing Ca as the ratio of bridge formation time to particle collision and separation time capture why agglomerates with high Ca struggle to grow. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T11:17:18.714829-05:
      DOI: 10.1002/aic.15761
  • Consensus Algorithm-Based Approach to Fundamental Modeling of Water Pipe
    • Authors: Shin Je Lee; Jingbo Wu, Jung Chul Suh, Gibaek Lee, Frank Allgöwer, Jong Min Lee
      Abstract: Modeling the flow dynamics of leaks in water pipe networks is an extremely difficult problem due to the complex entangled network structure and hydraulic phenomenon. We propose a mathematical model for leak dynamics in water pipe networks based on consensus algorithm and water hammer theory. The resulting model is a simple and linearly interconnected system even though the dynamics of water pipe networks has considerable complexity. The model is then validated using experimental data obtained from real pipe network. A comparative study demonstrates the proposed model can describe the real system with high qualitative and quantitative accuracy and it can be used to develop model-based leak detection and location algorithm based on state estimation. To show applicability of the proposed model, we apply cooperative estimation to the developed model. The results demonstrate the consensus based pipe model can be potentially used for leak detection and location with state estimation. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T11:17:12.335023-05:
      DOI: 10.1002/aic.15760
  • Validation of a CFD model of an Orbiting Culture Dish with PIV and
           Analytical Solutions
    • Authors: Jonathan Michael D Thomas; Mostafa Shakeri, Amlan Chakraborty, M. Keith Sharp, R. Eric Berson
      Abstract: Particle image velocimetry (PIV) and an extended solution of Stokes' second problem were used to validate a computational fluid dynamics (CFD) model of flow in an orbiting dish. Velocity vector components throughout one complete orbit differed between CFD and PIV by less than 5%. Computational velocity magnitudes averaged over the interior 20% radius, the region where the analytical solution is most applicable, were 0.3% higher than the analytical values, while the experimental values in the same region were 2.4% higher. Velocity profiles in the center of the dish across normalized heights that most influence wall shear stress varied on average by ∼-0.00046 for the normalized radial component and by ∼0.0038 for the normalized tangential component compared to the analytical solution. These results represent the most comprehensive validation to date for computational models of the orbiting dish system. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T11:06:01.122218-05:
      DOI: 10.1002/aic.15762
  • Hydrophobic Surface Modification of FMSS and its Application as Effective
           Sorbents for Oil Spill Clean-ups and Recovery
    • Authors: Oluwasola Oribayo; Qinmin Pan, Xianshe Feng, Garry L Rempel
      Abstract: Superhydrophobic sponge-like materials are attracting more attention in recent years as potential sorbent materials for oil-spill clean-up. In this work, we report the incorporation of hydrophobic structural features into a superhydrophilic pristine formaldehyde-melamine-sodium bisulfite copolymer Sponge (FMSS) by N-acylation with a fatty acid derivative, for use as an oil sorbent in oil-spill clean-ups. This resulted in our ability to transform the surface properties of the sponge skeleton to superhydrophobic with a contact angle of 143°. The acylated formaldehyde-melamine-sodium bisulfite copolymer Sponge (a-FMSS) was shown to retain the interconnected porous structure, and was characterized with microscopic and spectroscopic analyses. Sorption experiments with engine oil and chloroform showed that a-FMSS had a very high oil sorption capacity (amounting to 99 and 168.2 times its own weight respectively) than commercial nonwoven Polypropylene sorbent. In this view, a-FMSS is considered to be a promising oil sorbent for potential applications in large-scale oil-spill clean-ups. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T04:03:14.546982-05:
      DOI: 10.1002/aic.15767
  • Linking particle properties to dense suspension extrusion flow
           characteristics using discrete element simulations
    • Authors: Christopher Ness; Michele Marigo, Paul McGuire, Han Xu, Hugh Stitt, Jin Y. Ooi, Jin Sun
      Abstract: Extrusion is a widely used process for forming suspensions and pastes into designed shapes, and is central to the manufacture of many products. In this article, the extrusion through a square-entry die of non-Brownian spheres suspended in Newtonian fluid is investigated using discrete element simulations, capturing individual particle-particle contacts and hydrodynamic interactions. The simulations reveal inhomogeneous velocity and stress distributions, originating in the inherent microstructure formed by the constituent particles. Such features are shown to be relevant to generic paste extrusion behaviour, such as extrudate swell. The pressure drop across the extruder is correlated with the extrudate flow rate, with the empirical fitting parameters being linked directly to particle properties such as surface friction, and processing conditions such as extruder wall roughness. Our model and results bring recent advances in suspension rheology into an industrial setting, laying foundations for future model development, predictive paste formulation and extrusion design. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T03:59:19.423286-05:
      DOI: 10.1002/aic.15768
  • A Promising Technique of Aegle Marmelos Leaf Extract Mediated
           Self-Assembly for Silver Nanoprism Formation
    • Authors: K. Jagajjanani Rao; N. V. S. Praneeth, Santanu Paria
      Abstract: The Aegle marmelos leaf extract (LE) mediated synthesis of prismatic and spherical Ag nanoparticles has been studied. The formation of prismatic structures from spherical nanoparticles was observed microscopically using SEM, TEM and AFM. The shape transformation from spherical nanoparticles to prismatic nanostructures was studied by simply changing LE concentration, keeping constant AgNO3 concentration (1mM). The role of pH towards prism formation and the effect of sonication on the formed structures were also investigated. The antimicrobial activity of the synthesized Ag spherical/prismatic nanoparticles was evaluated against gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa) and on a phytopathogen Fusarium solani. This greensynthesis approach for the synthesis of prismatic Ag nanostructures may be useful for surface enhanced Raman spectroscopy (SERS) application for the detenction of low concentration organic molecules, apart from the studied antimicrobial activity. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T03:53:27.624799-05:
      DOI: 10.1002/aic.15766
  • Scaling Inter-tablet Coating Variability in a Horizontal Rotating Drum
    • Authors: J. Ban; R. Kumar, S. Agarwal, C. Wassgren
      Abstract: This study investigates how the drum-to-particle diameter ratio (D/d) affects the surface speed and inter-particle coating variability in geometrically similar coaters. Discrete element method simulations were used to model particle movement in different-sized, cylindrical drums with identical particle diameters, Froude numbers, fill volume fractions, and spray characteristics. The dimensionless streamwise surface speed profiles become increasingly symmetric as D/d increases, with the maximum speed increasing with D/d. The relationship between the maximum dimensionless speed and D/d is fit well with a power law expression. Inter-particle coating variability decreases with the square root of the number of drum revolutions after a sufficiently large number of drum revolutions. Increasing D/d increases, in a logarithmic manner, the number of drum revolutions required to reach a given degree of coating variability. A similar logarithmic coating variability trend was observed in simulations using almond-shaped pharmaceutical tablets, suggesting that the trend is independent of tablet shape. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-19T05:55:12.493545-05:
      DOI: 10.1002/aic.15758
  • Big data for microstructure-property relationships: A case study of
           predicting effective conductivities
    • Authors: Ole Stenzel; Matthias Neumann, Omar Pecho, Lorenz Holzer, Volker Schmidt
      Abstract: The analysis of big data is changing industries, businesses and research since large amounts of data are available nowadays. In the area of microstructures, acquisition of (3D tomographic image) data is difficult and time-consuming. It is shown that large amounts of data representing the geometry of virtual, but realistic 3D microstructures can be generated using stochastic microstructure modeling. Combining the model output with physical simulations and data mining techniques, microstructure-property relationships can be quantitatively characterized. Exemplarily, we aim to predict effective conductivities given the microstructure characteristics volume fraction, mean geodesic tortuosity and constrictivity. Therefore, we analyze 8119 microstructures generated by two different stochastic 3D microstructure models. This is - to the best of our knowledge - by far the largest set of microstructures that has ever been analyzed. Fitting artificial neural networks, random forests and classical equations, the prediction of effective conductivities based on geometric microstructure characteristics is possible. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-19T05:53:38.464866-05:
      DOI: 10.1002/aic.15757
  • More Active Ir Subnanometer Clusters than Single-Atoms for Catalytic
           Oxidation of CO at Low Temperature
    • Authors: Jian Lin; Yang Chen, Yanliang Zhou, Li Lin, Botao Qiao, Aiqin Wang, Jingyue Liu, Xiaodong Wang, Tao Zhang
      Abstract: This work reported the adsorption and reaction performance of FeOx supported subnanometer cluster and single-atom Ir catalysts for the oxidation of CO at low temperature. By varying the pretreatment temperature and Ir loading, the single-atom and subnanometer cluster Ir catalysts were obtained. The Ir subnanometer clusters exhibited higher activity for the oxidation of CO with or without the presence of H2 than the single-atom counterpart. By using adsorption microcalorimetry and in situ infrared spectroscopy measurements, it was found that the Ir subnanometer clusters not only promoted the adsorption and reaction of CO and O2 but also facilitated the formation of OH species from reaction between H2 and O2, thus opening a new reaction pathway between CO and OH species to produce CO2 compared with that between CO and O species on the single-atom counterpart. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-13T12:06:15.289639-05:
      DOI: 10.1002/aic.15756
  • Preemptive Dynamic Operation of Cryogenic Air Separation Units
    • Authors: Yanan Cao; Christopher L.E. Swartz, Jesus Flores-Cerrillo
      Abstract: As markets become more competitive and dynamic, manufacturing plants are undergoing transitions towards flexible, agile and low costs operations. Appropriate coordination within the supply chain is an important factor in manufacturing systems' performance. In this study, the impact of preemptive control action in advance of an upcoming demand change on the economic performance of a cryogenic air separation unit is investigated. The effects of various factors are explored through optimization formulations utilizing a high fidelity collocation based dynamic process model. This includes the amount of lead time, choice of manipulated inputs, direction of demand change, and liquid product market conditions. Plant performance is evaluated and analyzed through a comprehensive multi-part case study. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-10T11:35:36.36761-05:0
      DOI: 10.1002/aic.15753
  • Multi-parametric linear programming under global uncertainty
    • Authors: Vassilis M. Charitopoulos; Lazaros G. Papageorgiou, Vivek Dua
      Abstract: Multi-parametric programming has proven to be an invaluable tool for optimisation under uncertainty. Despite the theoretical developments in this area, the ability to handle uncertain parameters on the left-hand side remains limited and as a result, hybrid or approximate solution strategies have been proposed in the literature.In this work, a new algorithm is introduced for the exact solution of multi-parametric linear programming problems with simultaneous variations in the objective function's coefficients, the right-hand side and the left-hand side of the constraints. The proposed methodology is based on the analytical solution of the system of equations derived from the first order Karush-Kuhn-Tucker conditions for general linear programming problems using symbolic manipulation.Emphasis is given on the ability of the proposed methodology to handle efficiently the LHS uncertainty by computing exactly the corresponding non-convex critical regions while numerical studies underline further advantages of the proposed methodology, when compared to existing algorithms. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-10T11:35:35.228519-05:
      DOI: 10.1002/aic.15755
  • In-line Monitoring of Hydrogen Peroxide in Two-Phase Reactions using Raman
    • Authors: Fatemeh Ebrahimi; Jörn Viell, Alexander Mitsos, Markus Brandhorst, Adel Mhamdi
      Abstract: Hydrogen peroxide is an environment-friendly oxidizer, which is used in several chemical processes. However, safety necessitates the determination and control of the concentration of hydrogen peroxide during oxidation reactions. We propose a methodology to monitor hydrogen peroxide in disperse two-phase reaction mixtures based on in-line Raman spectroscopy. We compare indirect hard modelling (IHM), peak integration (PI) and partial least squares (PLS). Building predictive PLS and PI calibration models is challenging, whereas the IHM calibration is easy to develop. These methods show good accuracy for known samples (root mean square error of cross validation (RMSECV) of 0.3 to 0.7 wt%) compared to the classic titration method (RMSECV of 0.4 wt%). After calibration, inline monitoring during reaction is performed demonstrating that the concentration of hydrogen peroxide can be successfully monitored in a fast and reliable way by Raman spectroscopy. The IHM seems to give slightly better inline predictions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-10T11:35:33.925888-05:
      DOI: 10.1002/aic.15754
  • Dynamic Real-time Optimization with Closed-loop Prediction
    • Authors: Mohammad Zamry Jamaludin; Christopher L.E. Swartz
      Abstract: Process plants are operating in an increasingly global and dynamic environment, motivating the development of dynamic real-time optimization (DRTO) systems in order to account for transient behavior in the determination of economically optimal operating policies. This paper considers optimization of closed-loop response dynamics at the DRTO level in a two-layer architecture, with constrained MPC applied at the regulatory control level. A simultaneous solution approach is applied to the multilevel DRTO optimization problem, in which the convex MPC optimization subproblems are replaced by their necessary and sufficient Karush-Kuhn-Tucker (KKT) optimality conditions, resulting in a single-level mathematical program with complementarity constraints (MPCC). The performance of the closed-loop DRTO strategy is compared to that of the open-loop prediction counterpart through a multi-part case study that considers linear dynamic systems with different characteristics. The performance of the proposed strategy is further demonstrated through application to a nonlinear polymerization reactor grade transition problem. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-10T11:35:28.338417-05:
      DOI: 10.1002/aic.15752
  • Acceleration of Kinetic Monte Carlo Simulations of Free Radical
           Copolymerization: A Hybrid Approach with Scaling
    • Authors: Hanyu Gao; Ivan A. Konstantinov, Steven G. Arturo, Linda J. Broadbelt
      Abstract: Kinetic Monte Carlo (KMC) has been widely used in the simulation of polymeric reactions. The power of KMC is highlighted by its ability to keep track of the length and sequence of every radical or polymer chain, while it is computationally more expensive than deterministic kinetic models. This paper introduces an acceleration method that significantly reduces the computational cost of KMC simulations, while keeping the same features as the full kinetic Monte Carlo simulations. Case studies are used to demonstrate the general applicability of this method to free radical copolymerization. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-10T11:35:24.001979-05:
      DOI: 10.1002/aic.15751
  • Issue information
    • Abstract: Cover illustration. Intracellular delivery of nucleic acids by poly(beta-amino ester)s (PBAEs) requires multiple steps, including self-assembly into nucleic acid-containing PBAE nanoparticles, cellular internalization, endosomal escape, and cargo release at the target site. These nanoparticles have been used to deliver functional genes to treat brain cancer in novel ways. 10.1002/aic.15698
      PubDate: 2017-04-08T23:25:48.030802-05:
      DOI: 10.1002/aic.15471
  • Perspective: Teaching Professional Skills
    • Authors: Phil Wankat
      Abstract: After being invited to write a perspective on chemical engineering education for the AIChE Journal, I immediately wondered what I could contribute that had not already been covered in depth. After reading the previous Journal perspectives on chemical engineering education by Falconer1, Cussler2, and Varma and Grossmann3, I realized that development of professional skills (aka soft skills) had not been analyzed in detail. Professional skills such as communication, teamwork, and ethical behavior are often more important in an engineering career than technical ability. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-07T09:30:43.118685-05:
      DOI: 10.1002/aic.15747
  • A Fundamental Wax Deposition Model for Water-in-Oil Dispersed Flows in
           Subsea Pipelines
    • Authors: Sheng Zheng; Amir Haji-Akbari, H. Scott Fogler
      Abstract: Water-in-oil dispersions frequently form in subsea oil pipeline transportation and their presence affect the wax deposition rate in subsea pipelines. A fundamental model for wax deposition on the wall of water-in-oil dispersed phase flow pipelines has not been developed. Dispersed water droplets can affect the heat and mass transfer characteristics of wax deposition and alter the deposit growth rate. In this study, wax deposition from water-in-oil dispersed flows is comprehensively modeled using first principles of heat and mass transfer. The role of the dispersed water phase on the heat and mass transfer aspects of wax deposition is analyzed. The developed model predicts different effects of the water volume fraction and droplet size on the wax deposition rates in laboratory flow loop experiments and in field scale wax deposition processes. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-07T09:30:39.451058-05:
      DOI: 10.1002/aic.15750
  • Adaptive POD-DEIM basis construction and its application to a nonlinear
           population balance system
    • Authors: Lihong Feng; Michael Mangold, Peter Benner
      Abstract: We propose an adaptive algorithm for constructing reduced-order models of nonlinear systems based on proper orthogonal decomposition (POD) combined with the discrete empirical interpolation method (DEIM). Using an efficient output error estimation, the reduced basis and the DEIM interpolation basis are adaptively adjusted to derive a small, yet accurate reduced-order model. The adaptive algorithm is further explored for a population balance system of a crystallization process. Simulation results show that much smaller and reliable reduced-order models can be adaptively obtained using the algorithm with ignorable extra computational load as compared with the standard POD-DEIM method. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-07T09:30:30.981984-05:
      DOI: 10.1002/aic.15749
  • Fe-Beta@CeO2 Core–Shell Catalyst with Tunable Shell Thickness for
           Selective Catalytic Reduction of NOx with NH3
    • Authors: Jixing Liu; Jian Liu, Zhen Zhao, Yuechang Wei, Weiyu Song
      Abstract: A series of core−shell structural deNOx catalysts using small-grain Beta supporting FeOx nanoparticles (NPs) as the core and tunable CeO2 thin film thickness as sheaths were designed and controllably synthesized. Their catalytic performances were tested for selective catalytic reduction of NOx with NH3 (NH3-SCR). It was found that CeO2 shell thickness plays an important role in influencing the acidity and redox properties of the catalysts. Fe-Beta@CeO2 core−shell catalysts exhibit excellent resistance to H2O and SO2 and high NOx conversion (above 90%) in the wide temperature range (225∼565°C). The kinetics result indicates that the coating of CeO2 shell significantly increases the pore diffusion resistance of Fe-Beta@CeO2 catalysts. Furthermore, in-situ DRIFT results reveal that CeO2 shell can promote the formation of NO2 and cis-N2O2− species. But too thick CeO2 shell (∼20 nm) would result in the formation of inactive nitrate species, and thereby lead to a decrease of high-temperature activity of the catalysts. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-06T05:40:26.1216-05:00
      DOI: 10.1002/aic.15743
  • Fabrication of Supported Pd-Ir/Al2O3 Bimetallic Catalysts for
           2-Ethylanthraquinone Hydrogenation
    • Authors: Runrun Hong; Yufei He, Junting Feng, Dianqing Li
      Abstract: A series of χ wt.% Pd-(1-χ) wt.% Ir (χ=0.75, 0.50 and 0.25) catalysts supported on γ-Al2O3 have been prepared by co-impregnation and calcination-reduction, and subsequently employed in the hydrogenation of 2-ethylanthraquinone—a key step in the manufacture of hydrogen peroxide. Detailed studies showed that the size and structure of the bimetallic Pd-Ir particles vary as a function of Pd/Ir ratio. By virtue of its small metal particle size and the strong interaction between Pd and Ir, the 0.75 wt.% Pd-0.25 wt.% Ir/Al2O3 catalyst afforded the highest yield of H2O2, some 25.4% higher than that obtained with the monometallic 1 wt.% Pd catalyst. Moreover, the concentration of the undesired byproduct 2-ethyl-5,6,7,8-tetrahydroanthraquinone (H4eAQ) formed using the Pd-Ir bimetallic catalysts was much lower than that observed with the pure Pd catalyst, which can be assigned to the geometric and electronic effects caused by the introduction of Ir. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-06T05:34:39.33919-05:0
      DOI: 10.1002/aic.15748
  • Passive rate-based separation in collisional flows
    • Authors: Diana Lievano Bartlow; Tathagata Bhattacharya, J.J. McCarthy
      Abstract: The passive separation of a binary mixture of spherical particles is accomplished using a laboratory scale quasi two-dimensional inclined board such that gravity alone drives the flow of the mixture through a static array of obstacles. Experimental results compare well with simulations both qualitatively and quantitatively. An increase in separation is observed for increasing board length, whereas a decrease in separation is observed as the solid fraction (area coverage) of particles increases. This work demonstrates the possibility of designing green technology for solid-solid separations by taking advantage of particle properties that aid naturally occurring segregation. A probability based model is suggested as a way to predict the viability of separation between particle types as a function of particle size and coefficient of restitution. It should be noted that size separation is achieved despite peg spacings that are larger than both particles in a mixture. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T05:46:02.764424-05:
      DOI: 10.1002/aic.15744
  • Direct Measurement of Droplet Breakage in a Pulsed Disc and Doughnut
    • Authors: Hao Zhou; Shan Jing, Qi Fang, Shaowei Li, Wenjie Lan
      Abstract: The lack of experimental data for the droplet breakup has been one of the limitations for the application of population balance model (PBM). In this work, a high speed camera was used to directly measure the droplet breakup frequency and daughter size distribution in a pulsed disc and doughnut column. It was found from the captured video that multiple breakup events were more frequently observed than binary breakup. The multiple breakup was treated as an original breakup and several intermediate breakups in order to characterize the process quantitatively. The effects of pulsation intensity, dispersed phase flow rates and the spatial locations were investigated in detail. Empirical correlations were finally established for both the breakup frequency function and the daughter droplet size distribution function and fitted well with the experimental data. The correlation equations were then used in a simplified PBM to calculate the droplet number density, which further proved the feasibility of the correlations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T05:46:00.701507-05:
      DOI: 10.1002/aic.15742
  • Expeditious modeling of vapor transport and reactions in polymeric
    • Authors: Yunwei Sun; Charles Tong, Stephen J. Harley, Elizabeth A. Glascoe
      Abstract: We present a methodology for approximating dynamic adsorption of vapor coupled with diffusion in polymeric materials. In previous publications, the dynamic adsorption was represented by ordinary differential equations (ODEs) and solved in concentration and parameter space. To accelerate the calculation, we have developed a statistical approximation method using computationally cheap surrogate models (e.g., algebraic polynomials) that replace the ODE solutions of adsorption and are coupled with the diffusion equations. Since the polynomial presentation of the adsorption term is obtained in a standard format prior to modeling coupled sorption-diffusion, the adsorption operator can be expressed as input data in the transport code. Compared to conventional operator-splitting methods, the polynomial approximation (PA) of adsorption offers better computational efficiency. The methodology is demonstrated and validated using a dynamic Langmuir adsorption model that is coupled to diffusion and absorption models and applied to a water vapor sorption-diffusion process in polydimethlysiloxane (PDMS) polymers. [copyright] 2017 American Institute of Chemical Engineers AIChE J., 2017 This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T05:45:58.503589-05:
      DOI: 10.1002/aic.15746
  • Kinetics of the Liquid Phase Dehydration of 1-Octanol to di-n-octyl ether
           on Amberlyst 70
    • Authors: Carlos Casas; Roger Bringué, Carles Fité, Montserrat Iborra, Javier Tejero
      Abstract: The kinetics of the liquid phase dehydration of 1-octanol to di-n-octyl ether (DNOE) over Amberlyst 70 was studied at 413-453K. Mechanistic rate models assuming water and 1-octanol adsorbed on the resin, and the free sites fraction negligible, were selected from 1-octanol dehydration experiments. Next, the influence of DNOE, water and 1,4-dioxane (solvent) concentration was evaluated. DNOE and 1,4-dioxane do not affect significantly the reaction rate, while water inhibits it strongly. Water effect was quantified by splitting the rate constant into a "true one" and a correction factor related to the fraction of active sites blocked by water. The best kinetic model stemmed from an Eley-Rideal mechanism with water adsorbed onto the resin and DNOE released directly to the liquid phase, with a correction factor for water inhibitory effect based on a Freundlich isotherm-like function; activation energy being 110±5 kJ·mol−1 based in line with literature data on homologous reactions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T05:45:54.907818-05:
      DOI: 10.1002/aic.15741
  • Morphological Properties of Flocs under Turbulent Break-up and
           Restructuring Processes
    • Authors: M. Vlieghe; C. Frances, C. Coufort-Saudejaud, A. Liné
      Abstract: Bentonite flocculation was performed in a Taylor-Couette reactor coupled with an in situ method of image acquisition and analysis. A hydrodynamic sequencing is imposed in order to perform successive cycles of flocculation and breakage. Depending on the shear rate applied during the breakage step, one or two cycles are needed after the first flocculation step to recover a full reversibility on both size and shape factors. The breakup step produces flocculi that are the building blocks for the next. The re-flocculation steps produce smaller sizes and more regular shapes than the initial growth step. The floc size is calibrated by the turbulence as the radius of gyration is close to the Kolmogorov microscale whereas the floc structure is determined by flocculi aggregates. An analysis of the change of the flocs morphology, despite of their diversity, can also be achieved thanks to some relevant moments of the distributions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T05:45:48.182262-05:
      DOI: 10.1002/aic.15745
  • Gas-phase flow resistance of metal foams: Experiments and modelling
    • Authors: Marcin Piątek; Anna Gancarczyk, Marzena Iwaniszyn, Przemysław J. Jodłowski, Joanna Łojewska, Andrzej Kołodziej
      Abstract: Based on experimental results of gas flow resistance through two metal foams, NC 2733 and Ni 2733, a modelling is performed to adjudicate governing flow mechanism. Two essential models are considered: developing laminar flow within short capillary channel (i.e. foam pore) and flow around solid body (foam strut modelled as cylinder or sphere), each of them of some variants. Foam geometry was studied using computer microtomography. The model of flow around a sphere (diameter equal to strut thickness) gives the best conformity with experiments. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T18:05:37.765015-05:
      DOI: 10.1002/aic.15730
  • Modeling the Dynamics of Tamponade Multi-Component Gases During Retina
           Re-Attachment Surgery
    • Authors: Sheldon K. Hall; Thomas H. Williamson, Jean-Yves Guillemaut, Tony Goddard, Andrew P. Baumann, Joseph C. Hutter
      Abstract: Vitrectomy and pneumatic retinopexy are common surgical procedures used to treat retinal detachment. To re-attach the retina, gases are used to inflate the vitreous space allowing the retina to attach by surface tension and buoyancy forces that are superior to the location of the bubble. These procedures require the injection of either a pure tamponade gas, such as C3F8 or SF6, or mixtures of these gases with air. The location of the retinal detachment, the anatomical spread of the retinal defect, and the length of time the defect has persisted, will determine the suggested volume and duration of the gas bubble to allow re-attachment. After inflation, the gases are slowly absorbed by the blood allowing the vitreous to be re-filled by aqueous. We have developed a model of the mass transfer dynamics of tamponade gases during pneumatic retinopexy or pars plana vitrectomy procedures. The model predicts the expansion and persistence of intraocular gases (C3F8, SF6), oxygen, nitrogen, and carbon dioxide, as well as the intraocular pressure. The model was validated using published literature in rabbits and humans. In addition to correlating the mass transfer dynamics by surface area, permeability, and partial pressure driving forces, the mass transfer dynamics are affected by the percentage of the tamponade gases. Rates were also correlated with the physical properties of the tamponade and blood gases. The model gave accurate predictions in humans. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T18:02:30.339638-05:
      DOI: 10.1002/aic.15739
  • Theoretical Analysis of Natural Gas Recovery from Marginal Wells with a
           Deep Well Reactor
    • Authors: David Frederic Emerson; Amir Al Ghatta, Benjamin M. Woolston, Adrian Fay, Amit Kumar, Gregory Stephanopoulos
      Abstract: Current natural gas harvesting technologies are only economically viable at high gas flow rates. Subsequently, a significant quantity of gas remains unused in abandoned wells. Methanotrophic organisms are under development to capitalize on this resource given their preference for ambient conditions, however capital and methane mass transfer costs must be minimized. We propose using the well as the bioreactor negating capital costs, and leveraging the gas pressure for mass transfer. We evaluate the ‘Deep Well Reactor's feasibility by developing mathematical models to simulate mass transfer and explore how operating parameters impact ethanol production. The results show sufficient mass transfer for 100% conversion, despite minimal complexity. Current aerobic methanotrophs and inorganic catalysts provide sufficient reaction rates. Conversely, anaerobic methanotrophs rates must be improved by a factor of 1200. With an appropriate catalyst, this technology allows the recovery of methane at flow rates an order of magnitude lower than current technologies. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T18:02:26.59643-05:0
      DOI: 10.1002/aic.15738
  • Absorption Methods for the Determination of Mass Transfer Parameters of
           Packing Internals: A Literature Review
    • Authors: Laszlo Hegely; John Roesler, Pascal Alix, David Rouzineau, Michel Meyer
      Abstract: Methods for the determination of mass transfer coefficients and effective interfacial areas in packed absorption columns are reviewed. For each parameter, the methods are grouped into categories on the basis of their physical principle; the chemical systems used, experimental protocol, and the advantages and inconveniences are discussed. The treatment of end effects, the influence of packed bed height, and the recent efforts in standardization of measurement methods are also treated. The aim of the review is to give a broad overview of the methods used in literature in the last eight decades, some of which might be reconsidered in the light of modern measurement techniques and to evaluate them in relation to precision, practicality and hazardousness thereby to facilitate the search for reliable, precise and convenient experimental practices. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T18:02:24.364956-05:
      DOI: 10.1002/aic.15737
  • Comparative Performance of an Adiabatic and a Non-adiabatic PSA Process
           for Bulk Gas Separation - A Numerical Simulation
    • Authors: Rama Rao Vemula; Shivaji Sircar
      Abstract: A detailed numerical model of a Skarstrom-like PSA process is used to investigate the separation performance of an adiabatic and a non-adiabatic process for removal of bulk CO2 impurity from inert He. The complexity of the gas phase adsorbate composition, adsorbate loading, and the adsorbent temperature profiles as functions of positions inside an adsorber at the start and end of each step of the PSA process are discussed.The separation performance of a non-adiabatic PSA process is generally inferior to that of the corresponding adiabatic process. Smaller adsorbent column diameter accentuates non-adiabatic operation and hence lower separation efficiency. Furthermore, the separation efficiency decreases more rapidly at short cycle times and smaller column diameters. Insulation of PSA columns of a process development unit operated under these conditions is recommended for reliable data analysis. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T18:02:19.046566-05:
      DOI: 10.1002/aic.15740
  • Phase Distribution in Dispersed Liq-Liq Flow in Vertical Pipe: Mean and
           Turbulent Contribution of Interfacial Force
    • Authors: Mariem Rezig; Ghazi Bellakhal, Jamel Chahed
      Abstract: We applied an Eulerian-Eulerian two-fluid model on an upward dispersed oil-water flow in vertical pipe with 80 mm diameter and 2.5 m length. The numerical profiles of the radial distribution of the oil drops at 1.5 m from the inflow are compared to the experimental data of Lucas et al.1 This paper analyzes the roles of turbulence and interfacial forces on the phase distribution phenomenon. In liquid-liquid flow the relative velocity is low and the distribution of the dispersed phase is mainly governed by the turbulence. This work highlights the important role of the turbulent contribution obtained by averaging the added mass force on the radial distribution profiles of the oil drops. The numerical results present improved profiles of the dispersed phase comparing to the experimental data when this turbulent contribution is taken into account in the momentum balance. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T18:02:13.077471-05:
      DOI: 10.1002/aic.15736
  • Fluid Dynamic Characterization of a Laboratory Scale Rocked Bag Bioreactor
    • Authors: Douglas T. J. Marsh; Akinlolu O. O. Odeleye, Andrea Ducci, Matthew D. Osborne, Gary J. Lye, Martina Micheletti
      Abstract: Single-use technology is being widely adopted for the manufacture of biotherapeutics and cell therapy products. Rocked single-use bioreactors in particular have been commonly used, however the hydrodynamics have rarely been characterised and are poorly understood. In this work, phase-resolved Particle Image Velocimetry and high frequency visual fluid tracking were used to investigate the flow pattern and velocity characteristics for the first time. The studies were performed on an optically accessible mimic of a Sartorius 2L CultiBag at different conditions. Wave formation was observed and higher rocking speeds caused the fluid to move proportionately out of phase with respect to the platform. Dimensional comparisons of fluid velocities with conventional bioreactors suggest that similar fluid dynamics characteristics can be achieved between rocked and stirred configurations. These results provide a first insight into the fluid dynamics of a novel bioreactor type at relevant process conditions supporting the generation of scale translation laws. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T17:55:56.152237-05:
      DOI: 10.1002/aic.15734
  • Dearomatization of Pyrolysis Gasoline with an Ionic Liquid Mixture:
           Experimental Study and Process Simulation
    • Authors: Marcos Larriba; Pablo Navarro, Noemí Delgado-Mellado, Carlos González, Julián García, Francisco Rodríguez
      Abstract: The pyrolysis gasoline is the main source of benzene, toluene, and xylenes. The dearomatization of this stream is currently performed by liquid-liquid extraction using sulfolane. However, the Sulfolane process has high operating costs that could be minimized by employing ionic liquids (ILs) as solvents because of their non-volatile character. In this work, we proposed a novel process to perform the dearomatization of pyrolysis gasoline using a binary mixture of 1-ethyl-3-methylimidazolium tricyanomethanide ([emim][TCM]) and 1-ethyl-4-methylpyridinium bis(trifluoromethylsulfonyl)imide ([4empy][Tf2N]) ILs. The composition in the IL mixture was optimized considering their extractive and thermophysical properties. The Kremser method was applied using the experimental data to determine the number of equilibrium stages in the liquid-liquid extractor which provides the same extraction yields of aromatics using the IL mixture that those of the Sulfolane process. The recovery section was designed and simulated from the experimental vapor-liquid equilibrium between the hydrocarbons and the IL mixture. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T17:55:49.044256-05:
      DOI: 10.1002/aic.15735
  • Hydrodynamics of inclined packed beds under flow modulation - CFD
           simulation and experimental validation
    • Authors: Amir Motamed Dashliborun; Mohsen Hamidipour, Faïçal Larachi
      Abstract: A 3D unsteady-state Eulerian multi-fluid CFD model was developed to simulate the hydrodynamic behavior of inclined gas-liquid cocurrent downflow packed beds under ON-OFF liquid, ON-OFF gas, and gas/liquid alternating cyclic operations. Validation of the CFD simulation results was performed with experimental data provided by electrical capacitance tomography imaging. Incorporation in the Eulerian multi-fluid CFD model of capillary pressure and mechanical dispersion force was essential to accurately capture the transient spatial heterogeneities arising in tilted packed beds under different cyclic modulation strategies. The applied CFD model was able to satisfactorily predict the values of liquid holdup and pressure drop as well as the morphological characteristics of the traveling waves inside the bed for the examined flow modulations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T17:55:42.263759-05:
      DOI: 10.1002/aic.15732
  • Temporal clustering for order reduction of nonlinear parabolic PDE systems
           with time-dependent spatial domains: Application to a hydraulic fracturing
    • Authors: Abhinav Narasingam; Prashanth Siddhamshetty, Joseph Sang-Il Kwon
      Abstract: In this work, we present a temporally-local model order-reduction technique for nonlinear parabolic partial differential equation (PDE) systems with time-dependent spatial domains. In lieu of approximating the solution of interest using global (with respect to the time domain) empirical eigenfunctions, we derive low-dimensional models by constructing appropriate temporally-local eigenfunctions. Within this context, we partition the time domain into multiple clusters (i.e. subdomains) by using the framework known as global optimum search (GOS). This approach, a variant of Generalized Benders Decomposition (GBD), formulates clustering as a Mixed-Integer Nonlinear Programming problem and involves the iterative solution of a Linear Programming problem (primal problem) and a Mixed-Integer Linear Programming problem (master problem). Following the cluster generation, local (with respect to time) eigenfunctions are constructed by applying the proper orthogonal decomposition (POD) method to the snapshots contained within each cluster. Then, the Galerkin's projection method is employed to derive low-dimensional ordinary differential equation (ODE) systems for each cluster. The local ODE systems are subsequently used to compute approximate solutions to the original PDE system. The proposed local model order-reduction technique is applied to a hydraulic fracturing process described by a nonlinear parabolic PDE system with the time-dependent spatial domain. It is shown to be more accurate and computationally efficient in approximating the original nonlinear system with fewer eigenfunctions, compared to the model order-reduction technique with temporally-global eigenfunctions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T17:55:37.669343-05:
      DOI: 10.1002/aic.15733
  • Yield stress dependency on the evolution of bubble populations generated
           in consolidated soft sediments
    • Authors: Michael Johnson; Jeffrey Peakall, Michael Fairweather, Simon Biggs, David Harbottle, Timothy N. Hunter
      Abstract: Retention of hydrogen bubbles within consolidated soft sediments represents an important safety consideration for the management of legacy nuclear wastes due to the potential for acute gas release. Gas retention sufficiently reduced the bulk density of intermediate yield stress (< 800 Pa) sediments for the bed to become buoyant with respect to an aqueous supernatant, potentially inducing Rayleigh-Taylor instabilities. X-ray computed tomography revealed that beds of 7-234 Pa yield stress retained very similar, steady state size distributions of mature bubbles, limited to 9 mm equivalent spherical diameter, for long residence times. This implied a dominant gas release mechanism dictated by the pore to millimeter scale bubble population, not previously identified in such weak sediments and unrelated to the bubbles' buoyant force. At 1112 Pa yield stress, large bubbles of up to 20 mm diameter were observed to grow through induction of lateral cracks, facilitating gas transport to the bed periphery, thereby limiting the maximum void fraction, while non-homogeneous gas generation promoted the formation of low density regions rich with micro-bubbles which similarly provide pathways for gas release. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T17:50:38.485355-05:
      DOI: 10.1002/aic.15731
  • Reverse Osmosis Water Desalination: Quest for Sustainability
    • Authors: Yoram Cohen; Raphael Semiat, Anditya Rahardianto
      PubDate: 2017-04-03T02:25:33.362429-05:
      DOI: 10.1002/aic.15726
  • The Critical Condition for Thermal Explosion in an Isoperibolic System
    • Authors: D. Sánchez-Rodriguez; J. Farjas, P. Roura
      Abstract: Knowing the conditions for a system to undergo thermal explosion is of utmost importance for many applications. We present a critical condition that accounts for reactant consumption and covers most practical situations, including low activation energy reactions. Our solution applies to cylindrical reactors of any radius to height ratio. In the case of films, it is shown that thermal explosion is virtually impossible. We also introduce a new criterion to define the boundary of thermal runaway based on heat balance. This new definition of criticality allows us to check the accuracy of the non-stationary model to describe the critical condition. The non-stationary model is the base of most approaches. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-03T02:25:30.774382-05:
      DOI: 10.1002/aic.15727
  • Synthesis of Transparent Oil Dispersion of Monodispersed Calcium Carbonate
           Nanoparticles with High Concentration
    • Authors: Yuan Pu; Fang Kang, Jian-Feng Chen, Xiao-Fei Zeng, Jie-Xin Wang
      Abstract: The preparation of monodispersed inorganic nanoparticles is of great interest for many applications. In this article, transparent oil dispersion of monodispersed amorphous CaCO3 nanoparticles with high concentration and long-term stability were controllably prepared by a reverse microemulsion method. The effects of the addition amount of extra minute water and (NH4)2CO3 as novel assistant promoter, reaction temperature, Ca(OH)2/CaO mole ratio were explored. The optimum synthesis conditions were achieved. The as-prepared transparent oil nanodispersion had a good monodispersity, a uniform particle size of 8-10 nm, a high stability of over 12 months, a high solid content of 38 wt.% (Ca content of about 15.5 wt.%) and a high total base number (TBN) of 416 mgKOH/g. The preparation process was further investigated by polarized optical microscope (POM) and FTIR. This nanodispersion will find a promising applicability as an excellent nanodetergent in the fields of automobile and marine lubricants. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-03T02:25:26.031789-05:
      DOI: 10.1002/aic.15729
  • Heat Transfer Performance of NETmix – A Novel Micro-Meso Structured
           Mixer and Reactor
    • Authors: M. F. Costa; C. M. Fonte, M. M. Dias, J. C. B. Lopes
      Abstract: NETmix is a novel static mixing technology consisting on a network of unit cells, comprising chambers interconnected by channels. To assess the heat transfer capacity of NETmix, the NUB model was implemented to perform hydrodynamics and heat transfer simulations. Due to the periodic nature of the NETmix structure, two central chambers and six half-chambers were found to be sufficient to be representative of the whole network. The Nusselt numbers were determined based on the CFD simulations, and when compared with theoretical results for laminar flow between parallel plates, 3-5 times higher Nusselt number values were obtained with NETmix. This observed heat transfer rate enhancement, makes it suitable for fast reactions where heat transfer is crucial. Finally, results obtained from this study show that NETmix presents a heat transfer capacity one order of magnitude greater than microreactors, and 2-5 orders of magnitude greater than the most commonly used devices in industry. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-03T02:25:23.327928-05:
      DOI: 10.1002/aic.15728
  • Highly efficient recovery of propane by mixed-matrix membrane via
           embedding functionalized graphene oxide nanosheets into
    • Authors: Guoshun Shen; Jing Zhao, Kecheng Guan, Jie Shen, Wanqin Jin
      Abstract: To construct rapid C3H8 transport pathways in polymer matrix, alkyl chain-functionalized graphene oxide (GO) was prepared via grafting octadecylamine (ODA) molecules and then embedded into polydimethylsiloxane (PDMS) matrix to obtain high-efficiency mixed matrix membranes (MMMs). The incorporation of alkyl chains contributes to lowering the surface energy of GO nanosheets and providing higher affinity with PDMS matrix. Additionally, the alkyl chains on the surface of ODA-functionalized GO nanosheets (ODA-GO) are in favor of C3H8 adsorption, thus conferring continuous and specific transport pathways for C3H8. The optimized membrane with ODA-GO loading of 0.3 wt% exhibits the C3H8 permeance of 1897 GPU and the C3H8/N2 ideal selectivity of 67, which are 50.2 and 72.5% higher than those of bare PDMS membrane, respectively. The simultaneous enhancement of C3H8 permeance and C3H8/N2 ideal selectivity indicates that ODA-GO is an effective filler applied in MMMs for C3H8 recovery. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-29T09:45:31.406627-05:
      DOI: 10.1002/aic.15720
  • Investigation of the collapse of bubbles after the impact of a piston on a
           liquid free surface
    • Authors: Maya Mounir Daou; Elena Igualada, Hugo Dutilleul, Jean-Marie Citerne, Javier Rodríguez-Rodríguez, Stephane Zaleski, Daniel Fuster
      Abstract: We describe a novel technique based on the impact of a piston on a liquid confined in a vessel. Pressure measurements reveal that strong pressure variations (up to 100 atmospheres) with a rich content of frequencies are efficiently transmitted to the liquid. High-speed camera visualizations show that pre-existing millimetric bubbles always collapse during the first instants of the impact whereas the behavior of submillimetric bubbles depends on the features of the pressure evolution in the system. In addition to the impact velocity, the amount of gas/vapor trapped between the piston and the liquid's surface plays an important role on how pressure evolves. Only when negative pressure occurs bubbles grow significantly and collapse. The violent collapse of bubbles promote turbulence and mixing at very small length-scales which renders this technique interesting to intensify processes limited by heat and mass diffusion. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-29T03:50:23.273574-05:
      DOI: 10.1002/aic.15725
  • Dynamic Multiscale Method for Gas-Solid Flow via Spatiotemporal Coupling
           of Two-Fluid Model and Discrete Particle Model
    • Authors: Xizhong Chen; Junwu Wang
      Abstract: Various CFD methods have been developed to study the hydrodynamics of gas-solid flows, however, none of those methods is suitable for all the problems encountered due to the inherent multiscale characteristics of gas-solid flows. Both DPM (discrete particle model) and TFM (two-fluid model) have been widely used to study gas-solid flows, DPM is accurate but computationally expensive, whereas TFM is computationally efficient but its deficiency is the lack of reliable constitutive relationships in many situations. Here we propose a hybrid multiscale method (HMM) or dynamic multiscale method to make full use of both advantages of DPM and TFM, which is an extension of our previous publication from rapid granular flow (Chen et al., Powder Technology, 2016, 304: 177-185) to gas-solid two-phase flow TFM is used in the regions where it is valid and DPM is used in the regions where continuum description fails, they are coupled via dynamical exchange of parameters in the overlap regions. Simulations of gas-solid channel flow and fluidized bed demonstrate the feasibility of the proposed hybrid multiscale method. The Knudsen number distributions are also reported and analyzed to explain the differences. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-29T03:35:36.45721-05:0
      DOI: 10.1002/aic.15723
  • Algebraic modeling of the liquid film dynamics in a centrifugal separator
    • Authors: H.E.M. Ninahuanca; H. Stel, R.E.M. Morales
      Abstract: This work presents an algebraic model to estimate liquid film flow variables in a centrifugal separator. A mechanistic approach is employed to evaluate operating quantities such as the film thickness and velocity components. The model is based on a force balance on a fluid element of an idealized mean streamline. Additional terms account for the sudden spread of the inflowing stream at the entrance of the cylindrical chamber. A previously validated computational fluid dynamics (CFD) model is used to provide some constants for constitutive equations required by the algebraic model. Results from the algebraic and CFD models agree well for a wide range of Reynolds and Froude numbers. The proposed model can be useful to obtain fast and accurate predictions of the behavior of the liquid flow in the type of separators studied and to help designing more reliable and efficient concepts. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-29T03:35:24.736591-05:
      DOI: 10.1002/aic.15724
  • Dynamics of Hydrate Formation and Deposition under Pseudo Multiphase Flow
    • Authors: Jiafei Zhao; Bin Wang, Amadeu K. Sum
      Abstract: Gas hydrate formation is considered one of the major challenges in the flow assurance of deepwater oil and gas pipelines, as their blockage by hydrate can lead to significant production/economic loss and safety risk. Understanding the hydrate formation and deposition processes can improve the management methods in field development and production. This study used a high-pressure rocking cell to simulate multiphase flow conditions to visually investigate the hydrate formation and deposition from an oil-gas-water system. The changing hydrate morphologies, flow pattern and particle distribution during hydrate formation were studied and a conceptual model was proposed. The relative motion of hydrates to the cell wall and the final morphology of the hydrate chunks are found to be two critical parameters for evaluating hydrate deposition characteristics in the flow system. Five types of hydrate deposition morphologies are observed and these are correlated to the hydrate porosity. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-25T03:05:39.401114-05:
      DOI: 10.1002/aic.15722
  • DEM-PBM modelling of impact dominated ribbon milling
    • Authors: Simone Loreti; Chuan-Yu Wu, Gavin Reynolds, Andreja Mirtič, Jonathan Seville
      Abstract: Ribbon milling is a critical step in dry granulation using roll compaction as it determines the properties of granules, and subsequently the properties of final products. During ribbon milling, fragmentation of ribbons or flakes (i.e. compressed agglomerates from dry powders) are induced by either impact or abrasion. Understanding these fragmentation mechanisms is critical in optimising ribbon milling processes. In the current study, the discrete element method (DEM) was used to model fragmentation at the microscopic level, providing a detailed insight into the underlying breakage mechanism. In DEM modelling, virtual ribbons were created by introducing an appropriate interfacial energy using the cohesive particle model based upon the JKR theory. A set of three-dimensional parallelepiped ribbons with solid fraction φ = 0.7422 and surface energies ranging from γ = 0.0 J/m2 and γ = 2 J/m2 were created and then fractured during impacts with a plane at various impact velocities, in order to model impact dominated milling. The fragmentation rate, and the number and size of fragments (i.e. granules) resulting from the breakage of a ribbon during the impact were determined. The DEM simulations showed that the granules size distribution had a bimodal pattern and there was a strong correlation between the size of fines generated from fragmentation during impact and the size of the feed powder (i.e. the size of the primary particles in this study), which was consistent with the observation from physical experiments. Two quantities were calculated from the DEM simulations: the number of fragments p and the fraction of fines z for each breakage event which can be used as input parameters for population balance models (PBM) to develop a DEM-PBM modelling framework. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-23T03:50:47.894564-05:
      DOI: 10.1002/aic.15721
  • Effect of Membrane Morphology on Rising Properties of Filtration
           Resistance in Microfiltration of Dilute Colloids
    • Authors: Eiji Iritani; Nobuyuki Katagiri, Yuuki Yamashita
      Abstract: The effect of membrane morphology on the flux decline behaviors in dead-end unstirred microfiltration of very dilute colloids of polystyrene latex was examined using mixed cellulose ester and cellulose acetate membranes with interconnected tortuous pores and track-etched polycarbonate membranes with uniform straight cylindrical pores. The plots of reciprocal filtration rate against the filtrate volume per unit membrane area for the former two membranes exhibit concave downward curves in the initial period when the membrane pore blocking is significant, whereas the plot for the latter shows a concave upward curve in that period. The former results were described by a serial resistance model consisting of the initial membrane pore blocking followed by filter cake growth, and the latter was represented by a parallel resistance model in which the pore blocking and cake growth develop simultaneously from the beginning of filtration. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-23T03:50:38.435756-05:
      DOI: 10.1002/aic.15719
  • Selection of Oxygen Permeation Models for Different MIEC Membranes
    • Authors: Yue Zhu; Wenping Li, Yan Liu, Xuefeng Zhu, Weishen Yang
      Abstract: Permeation data of several mixed ionic-electronic conducting (MIEC) membranes were analyzed by two oxygen permeation models (i.e. Zhu's model and Xu-Thomson's model), respectively, to find a concise method to guide the choice of permeation models. We found that Zhu's model can well fit the permeation data of perovskite-type membranes, like Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) and BaCe0.05Fe0.95O3-δ (BCF), and dual-phase membranes, like 75wt%Ce0.85Sm0.15O1.925-25wt%Sm0.6Sr0.4Al0.3Fe0.7O3-δ (SDC-SSAF), whose oxygen vacancy concentrations are almost independent of the oxygen partial pressure at elevated temperatures. However, Zhu's model was not appropriate for membranes whose oxygen vacancy concentration changed obviously with oxygen partial pressure at elevated temperatures, such as La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) and La0.7Sr0.3CoO3-δ (LSC). On the contrary, Xu-Thomson's model can fit the data of LSCF and LSC well, but it is inapplicable for BSCF, BCF, and SDC-SSAF. Therefore, the dependence of oxygen vacancy concentration on oxygen partial pressure was suggested as an index for the selection of the permeation models. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-23T03:46:10.413122-05:
      DOI: 10.1002/aic.15718
  • Data-Driven Adaptive Nested Robust Optimization: General Modeling
           Framework and Efficient Computational Solution Algorithm for Decision
           Making under Uncertainty
    • Authors: Chao Ning; Fengqi You
      Abstract: We propose a novel data-driven adaptive robust optimization framework that leverages big data in process industries. A Bayesian nonparametric model – the Dirichlet process mixture model – is adopted and combined with a variational inference algorithm to extract the information embedded within uncertainty data. We further propose a data-driven approach for defining uncertainty set. This machine learning model is seamlessly integrated with adaptive robust optimization approach through a novel four-level optimization framework. This framework explicitly accounts for the correlation, asymmetry and multimode of uncertainty data, so it generates less conservative solutions. Additionally, the proposed framework is robust not only to parameter variations, but also to anomalous measurements. Because the resulting multi-level optimization problem cannot be solved directly by any off-the-shelf solvers, an efficient column-and-constraint generation algorithm is proposed to address the computational challenge. Two industrial applications on batch process scheduling and on process network planning are presented to demonstrate the advantages of the proposed modeling framework and effectiveness of the solution algorithm. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-22T19:01:44.651063-05:
      DOI: 10.1002/aic.15717
  • Predicting Phase Behavior in Aqueous Systems without Fitting Binary
           Parameters I: CP-PC-SAFT EOS, Aromatic Compounds
    • Authors: Polishuk Ilya; Yulia Sidik, Dong NguyenHuynh
      Abstract: This study examines an accuracy of CP-PC-SAFT attached by the 4C cross-association scheme and zero values of binary parameters in predicting the high temperature-high pressure phase behavior in aqueous systems of aromatic compounds containing one and two benzoic rings, CO2 and cis-decalin. In spite of the noteworthy complexity of these systems and the entirely predictive nature of the current approach, it correctly predicts the topology of phase behavior and typically yields the quantitatively accurate estimations of critical loci and the hydrocarbon-rich liquid phases in wide range of conditions. The available single phase volumetric data are also predicted accurately. Unfortunately, it is not a case of the water-rich phases exhibiting very small hydrocarbon concentrations. Nevertheless, the model is still capable of capturing the solubility minima characteristic for these phases around the room temperature. Predictions of the recent version of Simplified PC-SAFT proposed by Liang et al. (2014) are also discussed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-22T19:01:10.574953-05:
      DOI: 10.1002/aic.15715
  • Brick by Brick Computation of the Gibbs Free Energy of Reaction in
           Solution Using Quantum Chemistry and COSMO-RS
    • Authors: Arnim Hellweg; Frank Eckert
      Abstract: The computational modelling of reactions is simple in theory but can be quite tricky in practice. This article aims at the purpose of providing an assistance to a proper way of describing reactions theoretically and provides rough guidelines to the computational methods involved.Reactions in liquid phase chemical equilibrium can be described theoretically in terms of the Gibbs free energy of reaction. This property can be divided into a sum of three disjunct terms, namely the gas phase reaction energy, the finite temperature contribution to the Gibbs free energy, and the Gibbs free energy of solvation. The three contributions to the Gibbs free energy of reaction can be computed separately, using different theoretico–chemical calculation methods. While some of these terms can be obtained reliably by computationally cheap methods, for others a high level of theory is required to obtain predictions of quantitative quality.In order to propose workflows which can strike the balance between accuracy and computational cost, a number of benchmarks assessing the precision of different levels of theory is given.As an illustrative example, the low-temperature hydrogenation reaction of acetaldehyde to ethanol in solvent toluene is shown. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-22T19:01:08.01424-05:0
      DOI: 10.1002/aic.15716
  • Formation process of core-shell microparticles by solute migration during
           drying of homogenous composite droplets
    • Authors: Nan Fu; Winston Duo Wu, Zhangxiong Wu, Fei Tzhung Moo, Meng Wai Woo, Cordelia Selomulya, Xiao Dong Chen
      Abstract: Particle formation process during spray drying profoundly impacts particle morphology and microstructure. This study experimentally investigated the formation of core-shell-structured microparticles by one-step drying of composite droplets made of Eudragit® RS (a polycationic acrylic polymer in nanoparticle form) and silica sol. The formation of an incipient surface shell was monitored using single droplet drying technique, and the freshly formed shell was recovered for subsequent analyses. Adding silica to RS precursor increased the shell formation time and altered the properties of the incipient shell from water-dispersible to non-dispersible. The incipient shell formed from RS/silica droplets with mass ratios of 1.5%:1.5% and 0.5%:2.5% showed ingredient segregation with a preferential accumulation of RS, similar to the shell region of dried microparticles. After shell formation, excess silica sol in the liquid phase could flow inwards, producing a dense core. This mobility-governed solute migration would be useful for constructing core-shell microparticles using other precursor systems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-20T03:35:35.224604-05:
      DOI: 10.1002/aic.15713
  • A Superstructure-based Model for Multistream Heat Exchanger Design within
           Flowsheet Optimization
    • Authors: Harsha N. Rao; Iftekhar A. Karimi
      Abstract: Multistream heat exchangers (MHEXs) are often used in energy-intensive cryogenic processes. Modeling them within a process optimization formulation has been a challenge due to the needs to accommodate phase changes and ensure temperature approach. In this work, we present a nonlinear model for MHEXs based on a novel single-stage superstructure of two-stream exchangers. Our formulation guarantees a minimum temperature approach for all heat exchanges, estimates heat exchange areas for individual stream matches, requires no prior knowledge of phase changes, uses no Boolean variables, and enables seamless optimization of a process with multiple MHEXs. Furthermore, it facilitates dedicated constant-phase intervals that allow accurate estimation of heat transfer parameters for various stream matches. We optimize two natural gas liquefaction processes involving MHEXs, and report better solutions than the existing literature. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-20T03:35:30.355073-05:
      DOI: 10.1002/aic.15714
  • Optimal Water Management in Macroscopic Systems under Economic Penalty
    • Authors: Jaime Garibay-Rodriguez; Vicente Rico-Ramirez, Jose M. Ponce-Ortega
      Abstract: This paper proposes an integrated optimization approach to assess the sustainability of water management strategies in a macroscopic system. Those strategies include alternative water sources, such as rainwater harvesting, and the design of distributed water treatment systems. To deal with the economic challenges inherent to wastewater treatment, an economic penalization scheme is presented as an alternative that can achieve better cost-effectiveness and pollution abatement than traditional command and control practices. The proposed approach results in an MINLP multi-period model, which has been solved through the GAMS® modeling environment. The solution of our case-study allows finding the minimum investment to meet the desired environmental goals with respect to freshwater consumption and pollution abatement. Results include the number, size and location of rainwater storage devices as well as treatment technologies, the total amount of recycled wastewater and the total amount of fines charged to the users for violation of environmental regulations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-14T03:30:50.954051-05:
      DOI: 10.1002/aic.15712
  • Efficient removal of organic dye pollutants using covalent organic
    • Authors: Xiang Zhu; Shuhao An, Yu Liu, Jun Hu, Honglai Liu, Chengcheng Tian, Sheng Dai, Xuejing Yang, Hualin Wang, Carter W. Abney, Sheng Dai
      Abstract: A rational design and synthesis of covalent organic frameworks (COFs) displaying efficient adsorption of surrogates for common organic pollutants is demonstrated herein. Significantly, the top performing mesoporous triazine-functionalized polyimide COF exhibits superior adsorption of the small dye molecule methylene blue, achieving a maximum adsorption capacity of ∼1691 mg g−1 (∼169 wt %), surpassing the performance of all previously reported nanoporous adsorbents. The experimental results and accompanying in silico simulations suggest that both the size of the organic dye molecules and the intrinsic pore-size effect of the COF material should be taken into account simultaneously for the construction of COF-based adsorbents with efficient dyes adsorption capacities. The structural diversity of COF materials along with the understanding of the encapsulation of organic dyes on COFs holds great promise for developing novel COF adsorbents for the efficient removal of organic pollutants from wastewater. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-13T22:30:42.479794-05:
      DOI: 10.1002/aic.15699
  • Metal-free boron nitride adsorbent for ultra-deep desulfurization
    • Authors: Jun Xiong; Huaming Li, Lei Yang, Jing Luo, Yanhong Chao, Jingyu Pang, Wenshuai Zhu
      Abstract: Activated metal-free boron nitride (BN) adsorbent has been prepared by a surfactant assisted regulation strategy. By tuning the variety of surfactants (such as P123, PVP, F127), usage and reaction temperature, the adsorptive performance of activated BN was optimized. The optimized BN-P123 adsorbent displays porous structure with a high surface area about 1185 m2/g and exhibits excellent adsorptive desulfurization activity for dibenzothiophene (45.7 mg S/g adsorbent for 500 ppmw sulfur model oil), which is comparable or even superior to the state-of-the-art adsorbent. Additionally, this activated BN-P123 could realize the ultra-deep desulfurization through adsorptive process to reach the latest international standard (less than 10 ppmw). Considering the nontoxic metal-free feature and the excellent adsorption performance, the obtained activated BN-P123 may be a powerful candidate to meet the requirements of potential industrial applications. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-11T10:05:28.863551-05:
      DOI: 10.1002/aic.15695
  • On the modeling of the co2-catalyzed sintering of calcium oxide
    • Authors: Juan C. Maya; Farid Chejne, Suresh K. Bhatia
      Abstract: A comprehensive mathematical model for the CO2-catalyzed sintering of CaO is proposed. It takes into account the mechanisms of surface diffusion and grain boundary diffusion, catalyzed by CO2 chemisorption and dissolution, respectively. In addition, the model proposed here considers the change in pore size distribution during sintering, grain growth, and the densification by lattice diffusion, which is the intrinsic sintering mechanism of the CaO. Model predictions are validated using experimental data on the sintering of two CaO samples, one of them derived from pure CaCO3 and the other from limestone. It is found that impurities in limestone-derived CaO do not significantly affect the CO2 dissolution or chemisorption processes; however, they strongly increase the rate of sintering by lattice diffusion. It is also established that low temperatures and CO2 partial pressures promote the coarsening by surface diffusion, whereas high temperatures and CO2 partial pressures favor densification. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-11T09:55:32.27356-05:0
      DOI: 10.1002/aic.15696
  • Conceptual design of ammonia-based energy storage system: System design
           and time-invariant performance
    • Authors: Ganzhou Wang; Alexander Mitsos, Wolfgang Marquardt
      Abstract: Chemicals-based energy storage is promising for integrating intermittent renewables on the utility scale. High round-trip efficiency, low cost, and considerable flexibility are desirable. To this end, an ammonia-based energy storage system is proposed. It utilizes a pressurized reversible solid-oxide fuel cell for power conversion, coupled with external ammonia synthesis and decomposition processes and a steam power cycle. A coupled refrigeration cycle is utilized to recycle nitrogen completely. Pure oxygen, produced as a side-product in electrochemical water splitting, is used to drive the fuel cell. A first-principle process model extended by detailed cost calculation is used for process optimization. In this work, the performance of a 100 MW system under time-invariant operation is studied. The system can achieve a round-trip efficiency as high as 72%. The lowest levelized cost of delivered energy is obtained at 0.24 $/kWh, which is comparable to that of pumped hydro and compressed air energy storage systems. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-10T11:04:34.410192-05:
      DOI: 10.1002/aic.15660
  • Equation-Oriented Simulation and Optimization of Flowsheets with Detailed
           Spiral-Wound Multistream Heat Exchanger Models
    • Authors: Calvin Tsay; Richard C. Pattison, Michael Baldea
      Abstract: Multiple chemical processes rely on multistream heat exchangers (MHEXs) for heat integration, particularly at cryogenic temperatures. Owing to their geometric complexity, the detailed design of MHEXs is typically iterative: the exchanger geometric parameters are selected to match process specifications resulting from a flowsheet optimization step; then, the flowsheet is re-optimized with the predictions of the MHEX model, and these steps are repeated until a convergence criterion is met. This paper presents a novel framework that allows –for the first time, to our knowledge– for the simultaneous optimization of the process flowsheet and the detailed MHEX design. Focusing on spiral-wound MHEXs, we develop an equation-oriented exchanger model using industry-accepted heat transfer and pressure drop correlations for single- and multi-phase streams. We embed this model in our previously-developed pseudo-transient equation-oriented process simulation and optimization framework. We demonstrate our approach on an industrial case study, the PRICO® natural gas liquefaction process. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-10T10:34:56.806604-05:
      DOI: 10.1002/aic.15705
  • A New Qualitative Trend Analysis Algorithm based on Global Polynomial Fit
    • Authors: Bo Zhou; Hao Ye, Haifeng Zhang, Mingliang Li
      Abstract: Qualitative trend analysis (QTA) is an effective tool for process data analysis, the applications of which can be found in a variety of fields, such as process monitoring, fault diagnosis, and data mining. Reliable and accurate trend extraction of sensor data is the first and indispensable step in QTA. In this paper, a new trend extraction algorithm is developed that is based on global optimization of the polynomial fit of the process data. Different from most existing works, this newly proposed algorithm solves the trend extraction task by simultaneously and globally estimating the episode number, the boundary time points of the episode, and the fitted polynomial coefficients, which shows improved performance over other non-globally optimal trend extraction algorithms and requires less a priori knowledge than the existing globally optimal trend algorithms. The effectiveness of the algorithm is illustrated by testing on a variety of simulation and real blast furnace data. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-10T10:34:51.292253-05:
      DOI: 10.1002/aic.15706
  • Transport phenomena in Eccentric Cylindrical Coordinates
    • Authors: P. H. Gilbert; C. Saengow, A. J. Giacomin
      Abstract: Studies in transport phenomena have been limited to a select few coordinate systems. Specifically, Cartesian, cylindrical, spherical, Dijksman toroidal, and bipolar cylindrical coordinates have been the primary focus of transport work. The lack of diverse coordinate systems, for which the equations of change have been worked out, limits the diversity of transport phenomena problem solutions. Here, we introduce eccentric cylindrical coordinates and develop the corresponding equations of change (continuity, motion, and energy). This new coordinate system is unique, distinct from bipolar cylindrical coordinates, and does not contain cylindrical coordinates as a special case. We find eccentric cylindrical coordinates to be more intuitive for solving transport problems than bipolar cylindrical coordinates. Specific applications are given, in the form of novel exact solutions, for problems important to chemical engineers, in momentum, heat and mass transfer. We complete our analysis of eccentric cylindrical coordinates by using the new equations to solve one momentum, one energy, and one mass transport problem exactly. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-09T19:28:32.128503-05:
      DOI: 10.1002/aic.15671
  • Performance and kinetics of membrane and hybrid moving bed
           biofilm-membrane bioreactors treating salinity wastewater
    • Authors: Alejandro Rodríguez-Sánchez; Juan Carlos Leyva-Díaz, José Manuel Poyatos, Jesús González-López
      Abstract: A pilot-plant membrane bioreactor (MBR) and two pilot-plant hybrid moving bed biofilm reactor–membrane bioreactors (MBBR–MBRs), divided into three aerobic and one anoxic chambers, were started up for the treatment of salinity-amended urban wastewater. The MBBR–MBR systems worked with and without carriers in the anoxic zone (MBBR–MBRanox and MBBR–MBRn/anox, respectively). The systems were operated from start-up to stabilization, showing high removal of organic matter—a maximum of 90% chemical oxygen demand and 98% biochemical oxygen demand on the fifth day for MBBR–MBRn/anox in the stabilization phase—but low nitrogen elimination—30% maximum for MBBR–MBRn/anox in the stabilization phase. Biofilm attached to carriers reached less than 50 mg L−1 in the hybrid system. MBR showed faster kinetics than the two MBBR–MBR systems during start-up, but the opposite occurred during stabilization. Maximum specific growth rates for heterotrophic and autotrophic biomass were 0.0500 and 0.0059 h−1 for MBBR–MBRn/anox in the stabilization phase. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-09T11:25:27.071477-05:
      DOI: 10.1002/aic.15694
  • Data mining and control loop performance assessment: The multivariate case
    • Authors: Laya Das; Raghunathan Rengaswamy, Babji Srinivasan
      Abstract: Control loop performance assessment (CLPA) techniques assume that the data being analyzed is generated during steady state operation with fixed plant dynamics and controller parameters. However, in industrial settings one often encounters environmental and feedstock variations which can induce significant changes in the plant dynamics. Availability of data sets corresponding to fixed configurations is therefore questionable in industrial scenarios, in which case it becomes imperative to extract the same from routine plant operating data. This article proposes a technique for segmenting multivariate control loop data into portions corresponding to fixed steady state operation of the system. The proposed technique exploits the fact that changes in the operating region of the system lead to changes in variance-covariance matrix of multivariate control loop data. The univariate interval halving technique is fused with Mahalanobis distance to develop a multivariate tool that accounts for interactions between variables. The resulting data segments can be used for reliable CLPA and/or for user defined benchmarking of control loops. A multivariate control loop performance index is also proposed that requires significantly less data as compared to one of the previously proposed techniques. The proposed technique requires only routine operating data from the plant, and is tested on benchmark systems in the literature with simulations. Experimental validation on a model predictive control system aimed at maintaining the temperature profile of a metal plate demonstrates applicability of the technique to industrial systems. The proposed technique acts as a tool for preprocessing data relevant to CLPA and can be applied to large scale interacting multivariate systems. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-09T11:20:45.943263-05:
      DOI: 10.1002/aic.15689
  • Multi-Rate Observer Design for Process Monitoring Using Asynchronous
           Inter-Sample Output Predictions
    • Authors: Chen Ling; Costas Kravaris
      Abstract: In this paper, the problem of observer design in linear multi-output systems with asynchronous sampling is addressed. The proposed multi-rate observer is based on a continuous-time Luenberger observer design coupled with an inter-sample predictor for each sampled measurement, which generates an estimate of the output in between consecutive measurements. The sampling times are not necessarily uniformly spaced, but there exists a maximum sampling period among all the sensors. Sufficient and explicit conditions are derived to guarantee exponential stability of the multi-rate observer. The proposed framework of multi-rate observer design is examined through a mathematical example and a gas-phase polyethylene reactor. In the latter case, the amount of active catalyst sites is estimated, with a convergence rate that is comparable to the case of continuous measurements. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-09T05:40:47.233473-05:
      DOI: 10.1002/aic.15707
  • Experimental Investigations of Non-Newtonian/Newtonian Liquid-Liquid Flows
           in Microchannels
    • Authors: Evangelia Roumpea; Maxime Chinaud, Panagiota Angeli
      Abstract: The plug flow of a non-Newtonian and a Newtonian liquid was experimentally investigated in a quartz microchannel (200 μm ID). Two aqueous glycerol solutions containing xanthan gum at 1000 ppm and 2000 ppm were the non-Newtonian fluids and 0.0046 Pa s silicone oil was the Newtonian phase forming the dispersed plugs. Two-colour Particle Image Velocimetry was used to obtain the hydrodynamic characteristics and the velocity profiles in both phases under different fluid flowrates. The experimental results revealed that the increase in xanthan gum concentration produced longer, bullet-shaped plugs and increased the thickness of the film surrounding them. From the shear rate and viscosity profiles, it was found that the polymer solution was in the shear-thinning region while the viscosity was higher in the middle of the channel compared to the region close to the wall. Circulation times in the aqueous phase increased with the concentration of xanthan gum. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-09T05:40:44.468287-05:
      DOI: 10.1002/aic.15704
  • Microscopic Insights into the Efficiency of Capacitive Mixing Process
    • Authors: Manman Ma; Shuangliang Zhao, Honglai Liu, Zhenli Xu
      PubDate: 2017-03-09T05:40:43.439484-05:
      DOI: 10.1002/aic.15708
  • Gas Solubility in Long-Chain Imidazolium-Based Ionic Liquids
    • Authors: Chengna Dai; Zhigang Lei, Biaohua Chen
      PubDate: 2017-03-09T05:40:39.835876-05:
      DOI: 10.1002/aic.15711
  • Distributed Economic Model Predictive Control for Operational Safety of
           Nonlinear Processes
    • Authors: Fahad Albalawi; Helen Durand, Panagiotis D. Christofides
      Abstract: Achieving operational safety of chemical processes while operating them in an economically-optimal manner is a matter of great importance. Our recent work integrated process safety with process control by incorporating safety-based constraints within model predictive control (MPC) design; however, the safety-based MPC was developed with a centralized architecture, with the result that computation time limitations within a sampling period may reduce the effectiveness of such a controller design for promoting process safety. To address this potential practical limitation of the safety-based control design, in this work, we propose the integration of a distributed model predictive control architecture with Lyapunov-based economic model predictive control (LEMPC) formulated with safety-based constraints. We consider both iterative and sequential distributed control architectures, and the partitioning of inputs between the various optimization problems in the distributed structure based on their impact on process operational safety. Moreover, sufficient conditions that ensure feasibility and closed-loop stability of the iterative and sequential safety distributed LEMPC designs are given. A comparison between the proposed safety distributed EMPC controllers and the safety centralized EMPC is demonstarted via a chemical process example. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-09T05:40:30.948237-05:
      DOI: 10.1002/aic.15710
  • A New Model for Correlation and Prediction of Equilibrium CO2 Solubility
           in N-methyl-4-piperidinol Solvent
    • Authors: Min Xiao; Ding Cui, Helei Liu, Paitoon Tontiwachwuthikul, Zhiwu Liang
      Abstract: In this work, the equilibrium CO2 solubility in the aqueous tertiary amine,N-methyl-4-piperidinol (MPDL) was measured over a range of temperatures, CO2 partial pressures and amine concentrations. The dissociation constant of the MPDL solution was determined as well. A new thermodynamic model was developed to predict the equilibrium CO2 solubility in the MPDL-H2O-CO2 system. This model, equipped with the correction factor (Cf), can give reasonable prediction with an average absolute deviation of 2.0%, and performs better than other models (i.e. KE model, Li-Shen model and Hu-Chakma). The second-order reaction rate constant (k2) of MPDL and the heat of CO2 absorption (-ΔHabs) into aqueous MPDL solutions were evaluated as well. Based on the comparison with some conventional amines, MPDL revealed a high equilibrium CO2 loading, reasonably fast absorption rate when compared with other tertiary amines, and a low energy requirement for regeneration. It may therefore be considered to be an alternative solvent for CO2 capture. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-09T05:35:26.9795-05:00
      DOI: 10.1002/aic.15709
  • Biodegradable and Bioreducible Poly(beta-amino ester) Nanoparticles for
           Intracellular Delivery to Treat Brain Cancer
    • Authors: Yuan Rui; Gabriella Quiñones, Jordan J. Green
      Abstract: There is an urgent need for new treatment modalities to treat aggressive brain cancers such as glioblastoma. Recent advances in genetic nanomedicine hold great promise for innovative treatment strategies. In particular, polymeric nanoparticle-mediated delivery of DNA and short interfering RNA (siRNA) has the potential of safe and specific delivery to cancer cells that can achieve therapeutic effects through novel mechanisms of action. In this Perspective, we describe challenges for nucleic acid delivery to the brain as well as polymer and nanoparticle design strategies that can be used to overcome them. We highlight our development of poly(beta-amino ester)s (PBAEs), including biodegradable polymers that self-assemble with DNA into nanoparticles and bioreducible polymers that self-assemble with siRNA, for cancer therapy. The insights discovered by investigating PBAEs can enable researchers to further enhance nucleic acid delivery for a personalized precision medicine approach to treat brain cancer. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-08T03:40:39.405433-05:
      DOI: 10.1002/aic.15698
  • A spatially-averaged two-fluid model for dense large-scale gas-solid flows
    • Authors: Simon Schneiderbauer
      Abstract: We present a spatially-averaged two-fluid model (SA-TFM), which is derived from ensemble averaging the kinetic-theory based TFM equations. The residual correlation for the gas-solid drag, which appears due to averaging, is derived by employing a series expansion to the microscopic drag coefficient, while the Reynolds-stress-like contributions are closed similar to the Boussinesq-approximation. The subsequent averaging of the linearized drag force reveals that averaged interphase momentum exchange is a function of the turbulent kinetic energies of both, the gas and solid phase, and the variance of the solids volume fraction. Closure models for these quantities are derived from first principles. The results show that these new constitutive relations show fairly good agreement with the fine grid data obtained for a wide range of particle properties. Finally, the SA-TFM model is applied to the coarse grid simulation of a bubbling fluidized bed revealing excellent agreement with the reference fine grid solution. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-07T08:46:15.957647-05:
      DOI: 10.1002/aic.15684
  • Ceria-coated diesel particulate filters for continuous regeneration
    • Authors: Valeria Di Sarli; Gianluca Landi, Luciana Lisi, Almerinda Di Benedetto
      Abstract: The potential of diesel particulate filters wash-coated with highly dispersed nano-metric ceria particles for continuous regeneration has been investigated. To this end, catalytic filters were prepared, soot-loaded (avoiding the formation of the cake layer), and regenerated—under isothermal conditions—at temperature ranging from 200–600°C. Results have shown that catalytic oxidation of soot starts from 300°C and, at all temperatures, the selectivity to CO2 is higher than 99%. 475°C is the minimum temperature at which the filter is regenerated via catalytic path. At this temperature, the catalytic filter maintains substantially the same performance over repeated cycles of soot loading and regeneration, indicating that the thermal stability of ceria is preserved. This has been further confirmed by comparison between the outcomes obtained from characterization (X-ray powder diffraction, N2 adsorption at 77 K, Hg intrusion porosimetry, and scanning electron microscope/energy dispersive X-ray analysis) of fresh filter and filter subjected to repeated regeneration tests. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-07T08:40:45.270806-05:
      DOI: 10.1002/aic.15688
  • Volume diffusion in purification by sublimation
    • Authors: Narendra Singh; Thomas E. Schwartzentruber, Russell J. Holmes, E. L. Cussler
      Abstract: The amount sublimated of large organic molecules varies with the square of the diameter of the tube in which sublimation occurs. This implies that the velocity profile in the tube is nearly flat, consistent with volume diffusion, but not with laminar flow, Knudsen diffusion, or slip flow. However, molecular simulation calculations show that under the conditions used, the velocity profile is near parabolic when there is no deposition on the tube wall, inconsistent with volume diffusion, but in agreement with laminar flow. These calculations also show that deposition on the wall does result in velocity which is almost constant with radial position. The result is a laminar flow profile which is nearly flat, and hence a total flux proportional to the square of the tube diameter, which is observed both in these simulations and in physical experiments. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-07T08:30:44.402104-05:
      DOI: 10.1002/aic.15691
  • Liquid-like wave structure on granular film from granular jet impact
    • Authors: Zhe-Hang Shi; Wei-Feng Li, Hai-Feng Liu, Fu-Chen Wang
      Abstract: Results in the literature show that a granular film appears from a dense granular jet impacting on a circular target under certain conditions (Cheng X, Varas G, Citron D, Jaeger HM, Nagel SR, Phys Rev Lett. 2007; 99(18):188001). In current study, granular jet impacts are experimentally studied using a high-speed camera, and interesting liquid-like wave structures on the granular film are observed with increasing granular jet velocities or decreasing solid fractions of granular jets. Effects of the particle diameter, the granular jet velocity, and the solid fraction of granular jet on the wave structures are investigated. The dynamic characteristics of granular wave such as the wave frequency and velocity are demonstrated and compared with the liquid jet impact. Results reveal that increasing pushing pressure enhances the gas-particle interaction inside the nozzle, which causes the granular jet instability and further gives rise to the granular wave at lower solid fractions and higher granular jet velocities. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-07T08:20:39.040666-05:
      DOI: 10.1002/aic.15693
  • Molecular understanding of pyridinium ionic liquids as absorbents with
           water as refrigerant for use in heat pumps
    • Authors: Pablo B. Sánchez; Mounir Traikia, Alain Dequid, Agílio A. H. Pádua, Josefa García
      Abstract: Aiming at developing new absorbent/refrigerant working pairs for heat pumps, thermodynamic and transport properties of two pyridinium ionic liquids (ILs), N-ethylpyridinium bis(trifluoromethanesulfonyl)amide and N-ethylpyridinium trifluoromethanesulfonate were studied using molecular simulation and nuclear magnetic resonance techniques. The microscopic structure of the ILs and the solvation environment of water, including hydrogen bonding, were studied. Free-energies of solvation of water were obtained using perturbation methods, and the values agree with experimental observations. Self-diffusion coefficients and viscosity were computed and compared with nuclear magnetic resonance measurements and literature. Simulations predict slower dynamics when compared with experiment: diffusion coefficients are underpredicted, whereas viscosity is overpredicted. As such, simulation is consistent in a Stokes-Einstein sense. The trends in transport properties due to changing anion, to the presence of water and the effect of temperature are well predicted. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-07T08:12:20.641107-05:
      DOI: 10.1002/aic.15690
  • Modeling Study of Oxygen Permeation through an Electronically
           Short-Circuited YSZ-based Asymmetric Hollow Fiber Membrane
    • Authors: Yun Jin; Xiuxia Meng, Naitao Yang, Bo Meng, Jaka Sunarso, Shaomin Liu
      Abstract: Here, oxygen fluxes through an electronically short-circuited asymmetric Ag-YSZ YSZ LSM-YSZ hollow fiber prepared via a combined spinning and sintering route were tested and correlated to an explicit oxygen permeation model. The average oxygen permeation through such asymmetric hollow fiber with a 27 μm-thick YSZ dense layer reached 0.52 mL (STP) cm−2 min−1 at 1173 K. From the model results, we can obtain the characteristic thickness, the effects of the temperature, and the effect of He sweep gas flow rate to the individual step contribution. The oxygen partial pressure variation in the permeate side, the local oxygen flux, and the three different resistance distribution along the axial direction of the asymmetric hollow fiber are theoretically studied; providing guidelines to further improve the membrane performance for oxygen separation. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-07T03:50:38.886475-05:
      DOI: 10.1002/aic.15703
  • A Comparison of Efficient Uncertainty Quantification Techniques for
           Stochastic Multiscale Systems
    • Authors: Grigoriy Kimaev; Luis A. Ricardez-Sandoval
      Abstract: The aim of this paper is to compare the performance of efficient uncertainty propagation techniques (Polynomial Chaos (PCE) and Power Series (PSE) expansions) for uncertainty quantification in multiscale systems where discrete (molecular) scale is modelled without closed-form expressions. A multiscale model of thin film formation by chemical vapour deposition was used to study the effects of single parameter and multivariate uncertainty. For the single parameter uncertainty, 2nd order PSE approximations were the most accurate and computationally attractive. For the multivariate uncertainty, PSE performance deteriorated, while 2nd order PCE provided the highest accuracy when its expansion coefficients were calculated using the Least Squares method. However, comparable accuracy was achieved at half the computational cost when the coefficients were calculated using Non-Intrusive Spectral Projection (NISP). The response variables were subsequently controlled using robust optimization, and the results obtained using PCE NISP satisfied the optimization constraints more closely than other methods. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-07T03:26:18.364732-05:
      DOI: 10.1002/aic.15702
  • Mass Transfer Enhancement in Non-dispersive Solvent Extraction with
           Helical Hollow Fiber Enabling Dean Vortices
    • Authors: Qingran Kong; Youwei Cheng, Lijun Wang, Xi Li
      Abstract: In this work mass transfer enhancement of non-dispersive solvent extraction by use of helical hollow fiber membranes (HHFM) was investigated by means of experiment and model simulation. Purified terephthalic acid (PTA) wastewater treatment by extraction with p-xylene as solvent was chosen as the application case. Experiments showed that extraction efficiency of the HHFM was doubly enhanced compared with that of the straight hollow fiber. A comprehensive mathematical model of the HHFM extraction was developed in an orthogonal helical coordinate system with an analytical solution of the 3-D velocities. Model simulation revealed that Dean vortices circulate the peripheral fluid to the center, which enhances the mass transfer in the lumen side where radial diffusion is the rate determining step of the extraction. Relations of effluent impurity concentration and enhancement factor with the Graetz number and dimensionless curvature, were obtained by model simulation. Optimal parameters were selected for HHFM extraction design. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-07T03:26:17.064662-05:
      DOI: 10.1002/aic.15700
  • A novel CeO2 – xSnO2/Ce2Sn2O7 pyrochlore cycle for enhanced solar
           thermochemical water splitting
    • Authors: Chongyan Ruan; Yuan Tan, Lin Li, Junhu Wang, Xiaoyan Liu, Xiaodong Wang
      Abstract: A novel CeO2 – xSnO2/Ce2Sn2O7 pyrochlore stoichiometric redox cycle with superior H2 production capacities is identified and corroborated for two-step solar thermochemical water splitting (STWS). During the first thermal reduction step (1400°C), a reaction between CeO2 and SnO2 occurred for all the CeO2 – xSnO2 (x=0.05-0.20) solid compounds, forming thermodynamically stable Ce2Sn2O7 pyrochlore rather than metastable CeO2-δ. Consequently, substantially higher reduction extents were achieved owing to the reduction of CeIV to CeIII. Moreover, in the subsequent reoxidation with H2O (800°C), H2 production capacities increased by a factor of 3.8 as compared to the current benchmark material ceria when x=0.15, with the regeneration of CeO2 and SnO2 and the concomitant reoxidation of CeIII to CeIV. The H2O-splitting performance for CeO2 – 0.15SnO2 was reproducible over seven consecutive redox cycles, indicating the material was also robust. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-07T03:26:11.842241-05:
      DOI: 10.1002/aic.15701
  • Euler–euler anisotropic gaussian mesoscale simulation of homogeneous
           cluster-induced gas–particle turbulence
    • Authors: Bo Kong; Rodney O. Fox, Heng Feng, Jesse Capecelatro, Ravi Patel, Olivier Desjardins, Rodney O. Fox
      Abstract: An Euler–Euler anisotropic Gaussian approach (EE-AG) for simulating gas–particle flows, in which particle velocities are assumed to follow a multivariate anisotropic Gaussian distribution, is used to perform mesoscale simulations of homogeneous cluster-induced turbulence (CIT). A three-dimensional Gauss–Hermite quadrature formulation is used to calculate the kinetic flux for 10 velocity moments in a finite-volume framework. The particle-phase volume-fraction and momentum equations are coupled with the Eulerian solver for the gas phase. This approach is implemented in an open-source CFD package, OpenFOAM, and detailed simulation results are compared with previous Euler–Lagrange simulations in a domain size study of CIT. The results demonstrate that the proposed EE-AG methodology is able to produce comparable results to EL simulations, and this moment-based methodology can be used to perform accurate mesoscale simulations of dilute gas–particle flows. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-03T09:10:45.919574-05:
      DOI: 10.1002/aic.15686
  • Role of Free Surface on Gas-Induced Liquid Mixing in a Shallow Vessel
    • Authors: Abdul Quiyoom; S.K. Ajmani, Vivek V. Buwa
      Abstract: The present work is carried out to understand the effect of the free surface on liquid velocity distribution, dynamics and liquid phase mixing in a shallow Basic Oxygen Furnace (BOF). 3D/transient Euler-Lagrange (EL) without/with Volume-of-Fluid (VOF) simulations of dispersed gas-liquid flow in a scaled-down model of the BOF were performed. For lower H/D ratios, EL simulations performed with no-slip and free-slip boundary conditions led to oscillatory plume behaviour and higher liquid velocity regions which in turn led to smaller mixing time. In contrast, EL+VOF simulations led to reduced meandering motion of bubble plumes and lower liquid velocities resulting in higher mixing times. Interestingly, the mixing time predicted using EL+VOF approach was found to be in good agreement with the measurements. The results presented in this work show that the free surface has a significant effect on dynamics of gas-liquid flow and liquid phase mixing for shallow vessels with H/D ≤ 0.5. This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-02T18:20:32.76466-05:0
      DOI: 10.1002/aic.15697
  • Controlled surface topography of nanostructured particles prepared by
           spray-drying process
    • Authors: Ratna Balgis; Lusi Ernawati, Takashi Ogi, Kikuo Okuyama, Leon Gradon
      Abstract: Nanostructured particles (clusters) with complex and periodic topography at the microscopic scale show unique structural patterns. Hence, good properties should be obtained when the surface topography of such clusters, especially those containing nanoparticles (NPs) of different sizes, can be carefully tuned. The coffee-ring structure is one of the most interesting structures for catalyst and photonic crystal applications or porous particle molds. Here, well-defined clusters with a coffee-ring structure were prepared by spray drying. The complexity of the NP distribution in the resulting two- and three-component systems is discussed. A better understanding of how finite groups of different NPs self-organize in a moving droplet to form a confined geometry may aid in controlling the structure of matter at multiple length scales. Interestingly, the configuration of the large microsphere clusters was found to be influenced by the presence of the small particles, which formed a ring-like structure. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-02T01:06:10.333024-05:
      DOI: 10.1002/aic.15682
  • Aqueous-phase ketonization of acetic acid over Zr/Mn mixed oxides
    • Authors: Kejing Wu; Mingde Yang, Yu Chen, Weihua Pu, Husheng Hu, Yulong Wu
      Abstract: Aqueous-phase ketonization possesses significant advantages over gas- or organic-phase ketonization for improved conversion efficiency of aqueous fraction accompanied by algal bio-oil production. In this study, synthetized ZrO2 and Zr/Mn oxides are used for aqueous-phase ketonization of acetic acid. ZrMn0.5Ox shows the highest ketonization activity at 340°C for 12 h, achieving maximum acetone yield of 88.27%; and all catalysts exhibited selectivity higher than 96.75%. Apparent activation energy and acid reaction order are 161.2 kJ mol−1 and 0.70, respectively. Results suggest high ketonization activity of poorly crystallized tetragonal ZrO2. Addition of Mn results in ZrO2/MnOx solid solution and improves active sites. Acid property and Mn4+ content are important factors, and oxygen vacancy demonstrates relationship with ketonization activity for ZrO2. Examination of recovered catalysts indicates that ZrMnyOx exhibits improved stability, and Mn leaching and crystal phase transformation are main causes of deactivation in aqueous-phase ketonization. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-02T00:55:43.689402-05:
      DOI: 10.1002/aic.15687
  • In situ characterization of mixing and sedimentation dynamics in an
           impinging jet ballast tank via acoustic backscatter
    • Authors: Jaiyana Bux; Neepa Paul, Timothy N. Hunter, Jeffrey Peakall, Jonathan M. Dodds, Simon Biggs
      Abstract: Impinging jets are utilized in numerous applications, including nuclear waste treatment, for both the erosion of sediment beds and maintaining particulates in suspension. Pulse-echo ultrasonic methods offer great potential for the in situ monitoring of critical mixing and settling dynamics, in concentrated dispersions. A non-active scaled version of a Highly Active Storage Tank at Sellafield, UK, was profiled with an acoustic backscatter system under various jet firing conditions. An advanced analysis technique enabled the direct quantification of dispersion concentration changes from the converted backscatter attenuation. Hence, the erosion and mixing capability of the jets, and settling kinetics were characterized. It was found that jet operation alone provided inadequate localized mixing of eroded sediment. An additional air-lift process operation was required to hinder the rapid re-settling of dispersed particulates. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-02T00:50:59.491611-05:
      DOI: 10.1002/aic.15683
  • The kinetic modeling of carbonate formation during kraft pulping of
           eucalyptus wood
    • Authors: Jing Li; Huichao Hu, Xinsheng Chai
      Abstract: This article conducted an investigation on the carbonate formation during kraft pulping (KP) process of eucalyptus under different conditions, from which a kinetic model for predicting the carbonate formation was proposed. It was also found that the time-dependent effective alkali concentration and H factor are the major parameters affecting the carbonate formation. Results showed that the proposed model could describe the carbonate formation during KP at various process conditions, and there is a good correlation (R2 = 0.923) between the measured and predicted data. According to the model, about 54% of total carbonate formation was contributed from lignin in wood. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-01T05:48:23.38815-05:0
      DOI: 10.1002/aic.15681
  • Steam-air blown bubbling fluidized bed biomass gasification (BFBBG):
           Multi-scale models and experimental validation
    • Authors: Richard B. Bates; Ahmed F. Ghoniem, Whitney S. Jablonski, Daniel L. Carpenter, Christos Altantzis, Aaron Garg, John L. Barton, Ran Chen, Randall P. Field
      Abstract: During fluidized bed biomass gasification, complex gas-solid mixing patterns and numerous chemical and physical phenomena make identification of optimal operating conditions challenging. In this work, a parametric experimental campaign was carried out alongside the development of a coupled reactor network model which successfully integrates the individually validated sub-models to predict steady-state reactor performance metrics and outputs. The experiments utilized an integrated gasification system consisting of an externally-heated, bench-scale, 4-in., 5 kWth, fluidized bed steam/air blown gasifier fed with woody biomass equipped with a molecular beam mass spectrometer to directly measure tar species. The operating temperature (750–850°C) and air/fuel equivalence ratio (ER = 0–0.157) were independently varied to isolate their effects. Elevating temperature is shown to improve the char gasification rate and reduce tar concentrations. Air strongly impacts the composition of tar, accelerating the conversion of lighter polycyclic-aromatic hydrocarbons into soot precursors, while also improving the overall carbon conversion. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-03-01T05:35:54.148406-05:
      DOI: 10.1002/aic.15666
  • Sandwiched liquid metal membrane (SLiMM) for hydrogen purification
    • Authors: Pei-Shan Yen; Nicholas D. Deveau, Ravindra Datta
      Abstract: Palladium-based membranes are currently the most advanced membranes for hydrogen separation and are on the verge of practical application. However, the search for alternative membranes continues in an effort to lower their cost and susceptibility to poisons. Here for the first time we report a novel sandwiched liquid metal membrane (SLiMM) for hydrogen separation. Permeation experiments indicate that the Ga/SiC SLiMM has a permeability of 2.75 ×10−7 mol/ms⋅Pa0.5 at 500°C, which is 35 time higher than that for Pd under similar conditions. This promises a potential for application of SliMM in hydrogen purification. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-02-25T07:20:30.947539-05:
      DOI: 10.1002/aic.15658
  • Modularization Strategy for Syngas Generation in Chemical Looping Methane
           Reforming Systems with CO2 as Feedstock
    • Authors: Mandar Kathe; Charles Fryer, Peter Sandvik, Fanhe Kong, Yitao Zhang, Abbey Empfield, L.-S. Fan
      Abstract: This study considers a CO2 feedstock in conventional methane reforming processes and metal oxide lattice oxygen based chemical looping reforming. Lattice oxygen from iron-titanium composite metal oxide provides the most efficient co-utilization of CO2 with CH4. A modularization chemical looping strategy is developed to further improve process efficiencies using a thermodynamic rationale. Modularization leverages the ability of two or more reactors operating in parallel to produce a higher quality syngas than a single reactor operating alone while offering a direct solution to scale up of multiple parallel reactor processes. Experiments conducted validate the thermodynamic simulation results. Simulation and experimental results ascertain that a cocurrent moving bed in a modularization system can operate under CO2 neutral or negative conditions. The results for a modularization process system for 7,950 m3 per day (50,000 barrels per day) of liquid fuel indicate a ∼23% reduction of natural gas usage over baseline-case. This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-24T03:30:32.123598-05:
      DOI: 10.1002/aic.15692
  • Parameters affecting the localized fluidization in a particle medium
    • Authors: Sarah E. Mena; Li-Hua Luu, Pablo Cuéllar, Pierre Philippe, Jennifer Sinclair Curtis
      Abstract: The current study presents experiments for the initial stages of fluidization induced by a localized fluid injection. The process was studied by recording high-speed videos in a 2-D-region far from the boundaries using Planar Laser Induced Fluorescence and Refractive Index Matching. The experimental setup allowed for several parameters to be systematically studied including particle sizes, initial bed heights, and injection port diameters. The results show that the critical flow rate required for fluidization is primarily dependent on the initial height of the granular bed. However, this dependence is not a linear relation but progressively plateaus for larger heights. Conversely, the diameter of the chimney relates only slightly to the injection port diameter and significantly more to the diameter of the particles. © 2017 American Institute of Chemical Engineers AIChE J, 2017
      PubDate: 2017-02-10T08:36:02.620545-05:
      DOI: 10.1002/aic.15665
  • Magnetic ionic liquid-water Janus droplets: Preparation, structure and
           morphology adjustment and magnetic manipulation
    • Authors: Peng Guo; Changfeng Zeng, Chongqing Wang, Lixiong Zhang
      Abstract: Surfactant-free magnetic ionic liquid (MIL)-water Janus microdroplets with adjustable structures and morphologies are prepared in [[strike_start]]a[[strike_end]] capillary-based microfluidic devices. Their morphologies (e.g. sizes, curvatures of the interfaces and structures from Janus to core/shell) can be adjusted in a wide range by changing the flow rate ratio of water to MIL, adding different mass fractions of PEG in water, and using soybean oil rather than liquid paraffin as the continuous phase. MIL-water-MIL ternary Janus magnetic microdroplets with adjustable symmetric and asymmetric structures are also prepared. These Janus microdroplets can be manipulated by magnetic attraction, leading to easy formation of water-MIL-water, MIL-water-oil, necklace-structured MIL-water alternative Janus droplets as well as more complex Janus droplets, such as MIL-CO2-in-water and MIL-water-water droplets. Such preparation strategy is simple and can be applied in fields like pharmaceuticals, multi-drug chemotherapies, and catalysis with expensive materials. This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-06T11:15:37.352976-05:
      DOI: 10.1002/aic.15672
  • One-Pot Synthesis of Silver-Modified Sulfur-Tolerant Anode for SOFCs with
           an Expanded Operation Temperature Window
    • Authors: Jifa Qu; Wei Wang, Tao Yang, Yubo Chen, Zongping Shao
      Abstract: To develop solid oxide fuel cells (SOFCs) capable of operating on sulfur-containing practical fuels at intermediate temperatures, further improvement of the sulfur tolerance of a Ni+BaZr0.4Ce0.4Y0.2O3-δ (BZCY) anode is attempted through the addition of some metal modifiers (Fe, Co and Ag) by a one-pot synthesis approach. The effects of these modifiers on the electrical conductivity, morphology, sulfur tolerance and electrochemical activity of the anode are systematically studied. As a result, the cell with Ag-modified Ni+BZCY anode demonstrates highest power output when operated on 1000 ppm H2S-H2 fuel. Furthermore, the Ag-modified anode displays much better stability than Ni+BZCY with 1000 ppm H2S-H2 fuel at 600°C. These results suggest that the addition of Ag modifier into Ni+BZCY is a promising and efficient method for improving the sulfur tolerance of SOFCs. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-17T04:36:22.37746-05:0
      DOI: 10.1002/aic.15649
  • Issue information - table of contents
    • Pages: 1469 - 1469
      PubDate: 2017-04-08T23:25:47.962008-05:
      DOI: 10.1002/aic.15470
  • Dynamic analysis and open-loop start-up of an integrated radiant syngas
           cooler and steam methane reformer
    • Authors: Jaffer H. Ghouse; Dominik Seepersad, Thomas A. Adams
      Pages: 1602 - 1619
      Abstract: The transient performance of an integrated radiant syngas cooler (RSC) of an entrained-bed gasifier and steam methane reformer (SMR) is investigated. Base-case designs using either co-current or counter-current configurations are subjected to operating transients to evaluate the feasibility to transition to new steady states. Each system, under open loop, is subjected to changes in key variables of the SMR feed on the tube side and disturbances to variables of the coal-derived syngas on the RSC side to determine the dynamics and stability of the integrated system. The results indicate that the co-current configuration is flexible to move to new operating steady states and more safe than the counter-current configuration, although it provides less cooling and has poorer methane conversion. The variables likely to violate the design limit in the event of a disturbance are identified. A start-up procedure is also established based on industrial practices employed for entrained-bed gasifiers and methane reformers. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1602–1619, 2017
      PubDate: 2017-02-04T21:30:29.845115-05:
      DOI: 10.1002/aic.15655
  • Integration of biofuels intermediates production and nutrients recycling
           in the processing of a marine algae
    • Authors: Ali Teymouri; Sandeep Kumar, Elena Barbera, Eleonora Sforza, Alberto Bertucco, Tomas Morosinotto
      Pages: 1494 - 1502
      Abstract: The cost-effective production of liquid biofuels from microalgae is limited by several factors such as recovery of the lipid fractions as well as nutrients management. Flash hydrolysis, a rapid hydrothermal process, has been successfully applied to fractionate the microalgal biomass into solid biofuels intermediates while recovering a large amount of the nutrients in the aqueous phase (hydrolyzate) in a continuous flow reactor. The aim of the work is to enhance the quality of a high-ash containing marine algae Nannochloropsis gaditana as biofuel feedstock while recycling nutrients directly for algae cultivation. Characterization of products demonstrated an increase in extractable lipids from 33.5 to 65.5 wt % (dry basis) while retaining the same fatty acid methyl ester profile, in addition to diminution of more than 70 wt % of ash compared to raw microalgae. Moreover, the hydrolyzate was directly used to grow a microalga of the same genus. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1494–1502, 2017
      PubDate: 2016-10-21T10:45:36.723461-05:
      DOI: 10.1002/aic.15537
  • Minimum pickup velocity: The transition between nano-scale and micro-scale
    • Authors: Aditya Anantharaman; J. Ruud van Ommen, Jia Wei Chew
      Pages: 1512 - 1519
      Abstract: The transport of nano-scale particles has become increasingly important, but the knowledge base available is limited. This study aims to bridge the knowledge gap between the nano- and micro-scales for pneumatic conveying. A key parameter is the minimum pickup velocity (Upu), which is the minimum fluid velocity required to initiate motion in a particle originally at rest. The Upu values of nine alumina particles with particle diameters (dp) ranging from 5 to 110,000 nm were determined using the weight loss method, then compared against the established pickup Zones (analogous to the Geldart Groups). Results indicated that: (1) Upu varied non-monotonically with increasing dp, thus revealing the missing link between the nano- and micro-scales; (2) the intermediate particle diameters surprisingly did not agree with any pickup Zone; (3) Zone III (analogous to Geldart Group C) is inadequate for all the nano-scale particles, so new boundaries and a new Zone are proposed. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1512–1519, 2017
      PubDate: 2016-10-14T09:31:12.651266-05:
      DOI: 10.1002/aic.15527
  • Correction of wall adhesion effects in the centrifugal compression of
           strong colloidal gels
    • Authors: Richard Buscall; Daniel R. Lester
      Pages: 1520 - 1528
      Abstract: Several methods for measuring the compressive strength of strong particulate gels are available, including the centrifuge method, whereby the strength as a function of volume-fraction is obtained parametrically from the dependence of equilibrium sediment height upon acceleration. The analysis used conventionally due to Buscall & White (1987) ignores the possibility that the particulate network might adhere to the walls of the centrifuge tube, even though many types of cohesive particulate gel can be expected to. The neglect of adhesion is justifiable when the ratio of the shear to compressive strength is small, which it can be for many systems away from the gel-point, but never very near it. The errors arising from neglect of adhesion are investigated theoretically and quantified by synthesising equilibrium sediment height versus acceleration data for various degrees of adhesion and then analysing them in the conventional manner. Approximate correction factors suggested by dimensionless analysis are then tested. The errors introduced by certain other approximations made routinely in order to render the data-inversion practicable are analysed too. For example, it shown that the error introduced by treating the acceleration vector as approximately one-dimensional is minuscule for typical centrifuge dimensions, whereas making this assumption renders the data inversion tractable. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1520–1528, 2017
      PubDate: 2016-10-21T10:35:27.683905-05:
      DOI: 10.1002/aic.15528
  • Optimization of large-scale water transfer networks: Conic integer
           programming model and distributed parallel algorithms
    • Authors: Li-Juan Li; Rui-Jie Zhou
      Pages: 1566 - 1581
      Abstract: The optimization of a multi-echelon water transfer network (WTN) and the associate transportation and inventory systems with demand uncertainty is addressed in article. Optimal network structure, facility locations, operation capacities, as well as the inventory and transportation decisions can be simultaneously determined by the mixed integer nonlinear programming (MINLP) model which includes bilinear, square root and nonlinear fractional terms. By exploiting the properties of this model, we reformulate the MINLP problem as a conic integer optimization model. To overcome the memory and computing bandwidth limitations caused by the huge number of active nodes in the branch-and-bound search tree, novel distributed parallel optimization algorithms based on Lagrangean relaxation and message passing interface as well as their serial versions are proposed to solve the resulting conic integer programming model. A regional WTN in China is studied to demonstrate the applicability of the proposed model and the performance of the algorithms. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1566–1581, 2017
      PubDate: 2016-10-17T12:45:31.876934-05:
      DOI: 10.1002/aic.15505
  • Large-scale heat exchanger networks synthesis using simulated annealing
           and the novel rocket fireworks optimization
    • Authors: Leandro Vitor Pavão; Caliane Bastos Borba Costa, Mauro Antonio da Silva Sá Ravagnani, Laureano Jiménez
      Pages: 1582 - 1601
      Abstract: Heat Exchanger Network (HEN) synthesis is an important field of study in process engineering. However, obtaining optimal HEN design is a complex task. When mathematically formulated, it may require sophisticated methods to achieve good solutions. The complexity increases even more for large-scale HEN. In this work, a hybrid meta-heuristic method is presented. A rather simple Simulated Annealing approach is used for the combinatorial level, while a strategy named rocket fireworks optimization is developed and applied to the continuous domain. An advantage over other approaches is that the algorithm was written in C++, which is free and faster when compared to many other languages. The developed method was able to provide the lowest costs solutions reported so far to six cases well studied in the literature. An important feature of the approach here proposed is that, differently from other approaches, it does not split HEN into smaller problems during the optimization. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1582–1601, 2017
      PubDate: 2016-10-21T10:50:29.490932-05:
      DOI: 10.1002/aic.15524
  • Three-dimensional modeling of porosity development during the gasification
           of a char particle
    • Authors: Kay Wittig; Petr A. Nikrityuk, Sebastian Schulze, Andreas Richter
      Pages: 1638 - 1647
      Abstract: This work is devoted to the three-dimensional, direct modeling of porosity and specific surface development during the gasification of a char particle. The model was developed for heterogeneous reactions occurring inside a char particle in a kinetically controlled regime. The main goal of this work is to analyze the impact of different pore size distributions on the particle carbon conversion rate. In particular, it is shown that under certain conditions the outer particle surface can influence the specific surface area. In this context the possible adaptation of the parameter ψ from the random pore model (RPM) developed by Bhatia and Perlmutter is explained. The results of simulations are compared against the RPM and discussed. Additionally, based on the results of simulations, the physics behind several input parameters used by the RPM are explored. Finally, the possible fragmentation of a chemically reacting char particle during its gasification in dependence of instantaneous porosity was investigated numerically. It was shown that the earliest fragmentation occurs at a carbon conversion of about 0.5–0.6 due to the disaggregation of the pore walls. The results are discussed and compared implicitly with data published in the literature. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1638–1647, 2017
      PubDate: 2016-10-17T12:40:29.327277-05:
      DOI: 10.1002/aic.15526
  • N-doped porous carbons for CO2 capture: Rational choice of N-containing
           polymer with high phenyl density as precursor
    • Authors: Jian-Cheng Geng; Ding-Ming Xue, Xiao-Qin Liu, Yao-Qi Shi, Lin-Bing Sun
      Pages: 1648 - 1658
      Abstract: N-doped porous carbons (NPCs) are highly promising for CO2 capture, but their preparation is severely hindered by two factors, namely, the high cost of N-containing polymer precursors and the low yield of carbon products. Here we report for the first time the fabrication of NPCs through the rational choice of the polymer NUT-4, with low cost and high phenyl density, as precursor. For the material NPC-600 obtained from carbonization at 600°C, the yield is as high as 52.1%. The adsorption capacity of CO2 on NPC-600 reaches 6.9 mmol/g at 273 K and 1 bar, which is obviously higher than that on the benchmarks, including 13X zeolite (4.1 mmol/g) and activated carbon (2.8 mmol/g), as well as most reported carbon materials. Our results also demonstrate that the present NPCs can be completely regenerated under mild conditions. The abundant microporosity and “CO2-philic” (N-doped) sites are responsible for the adsorption performance. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1648–1658, 2017
      PubDate: 2016-10-14T09:36:00.083335-05:
      DOI: 10.1002/aic.15531
  • Continuous fractionation of multicomponent mixtures with sequential
           centrifugal partition chromatography
    • Authors: Johannes Goll; Mirjana Minceva
      Pages: 1659 - 1673
      Abstract: The applicability of sequential centrifugal partition chromatography for continuous fractionation of multicomponent mixtures, represented here by a mixture of four parabens with very similar molecular structure, was studied. The fractionation of the quaternary feed mixture was regarded as a separation of a pseudo-binary mixture. The model-based approach was used to select the biphasic liquid system and the unit operating parameters. All desired fractions were recovered with purities >99%. The influence of the solute concentration on the density, viscosity and volume ratio of the phases as well as on the partitioning of the solutes between the two phases was investigated. According to these results, possibilities for increasing the throughput were proposed and validated experimentally. For example, butyl paraben with a purity ≥99% was continuously separated from the rest of the parabens in a 250 mL unit with a throughput of 3.24 g h−1 and a solvent consumption of 0.33 L g−1. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1659–1673, 2017
      PubDate: 2016-10-17T12:50:27.848482-05:
      DOI: 10.1002/aic.15529
  • Hydrogen bond lifetimes and statistics of aqueous mono-, di- and
           tri-ethylene glycol
    • Authors: Richard Olsen; Bjørn Kvamme, Tatiana Kuznetsova
      Pages: 1674 - 1689
      Abstract: Hydrogen bond statistics, energy distributions of hydrogen bonds and hydrogen bond lifetimes for aqueous monoethylene glycol (MEG), diethylene glycol (DEG), and triethylene glycol (TEG) were investigated at temperatures ranging from 275 to 370 K at 101.325 kPa using molecular dynamics simulations. Each individual type of hydrogen bond were studied separately to better understand how each type of hydrogen bond affected the collective behavior often measured in experiments. We also studied the effects of glycols on water–water hydrogen bond structures and lifetimes. Decay constants for hydroxyl type hydrogen bonds, as well as for water based hydrogen bonds were in the same order, thus indicating that all these hydrogen bonds play an essential role in the process of dielectric relaxation. Correlations between water hydrogen bond distances and angles were not affected markedly by adding glycols. However, hydrogen bond lifetimes increased by 9, 29, and 62 times by adding MEG, DEG, and TEG, respectively. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1674–1689, 2017
      PubDate: 2016-10-21T10:55:34.828468-05:
      DOI: 10.1002/aic.15539
  • Absorption of picoliter droplets by thin porous substrates
    • Authors: Hua Tan
      Pages: 1690 - 1703
      Abstract: Absorption of picoliter (pL) droplets into porous substrates is studied experimentally and numerically. In the case of pL droplets, major phenomena involved in the interaction between droplet and porous media develop at different time scales: spreading and wetting at microseconds, absorption and wicking at milliseconds, and evaporation at seconds. Therefore, one can decouple these processes to minimize the complexity of the study. A high-speed imaging system capable of 1 million frames per second is used to visualize individual droplets impacting, spreading, and imbibing on substrates. To simulate droplet dynamics, the governing equations for flow outside and inside porous media are proposed and solved using an in-house developed computational fluid dynamics solver. The simulation results are in good agreement with the experimental data. The effect of drop impact velocity and fluid properties on final dot shape in the porous substrates is investigated through a series of parametric numerical studies. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1690–1703, 2017
      PubDate: 2016-10-10T09:45:32.522091-05:
      DOI: 10.1002/aic.15525
  • Surface wettability effect on fluid transport in nanoscale slit pores
    • Authors: Shuangliang Zhao; Yaofeng Hu, Xiaochen Yu, Yu Liu, Zhi-Shan Bai, Honglai Liu
      Pages: 1704 - 1714
      Abstract: The surface wettability effect on fluid transport in nanoscale slit pores is quantitatively accessed by using non-equilibrium molecular dynamics (NEMD) simulation incorporating with density functional theory (DFT). In particular, the slip lengths of benzene steady flows under various wetting conditions are computed with NEMD simulations and a quasi-general expression is given, while the structural properties are investigated with DFT. By taking into account the inhomogeneity of fluid density inside pore, we find that the conventional flux enhancement rate is associated with both the molecule slipping and geometrical confinement, and it becomes drastically high in solvophobic pores especially when the pore size is of several fluid diameters. In good agreement with experimental results, we further show that the wettability effect competes with pore size effect in determining the flux after pore inner surface modification, and a high flux can be achieved when the deposited layer is solvophobic yet thin. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1704–1714, 2017
      PubDate: 2016-10-18T13:35:31.922763-05:
      DOI: 10.1002/aic.15535
  • Periodic reactive flow simulation: Proof of concept for steam cracking
    • Authors: David J. Van Cauwenberge; Laurien A. Vandewalle, Pieter A. Reyniers, Kevin M. Van Geem, Guy B. Marin, Jens Floré
      Pages: 1715 - 1726
      Abstract: Streamwise periodic boundary conditions (SPBCs) have been successful in reducing the computational cost of simulating high aspect ratio processes. Extending beyond the classic assumptions of constant property flows, a novel approach incorporating non-equilibrium kinetics was developed and implemented for the simulation of an industrial propane steam cracker. Comparison with non-periodic benchmarks provided validation as relative errors on the main product yields were consistently below 1% for different reactor configurations. A further order-of-magnitude reduction of the radial errors on product concentrations was obtained via an intuitive correction method based on the concept of local fluid age. The computational speedup achieved through application of SPBCs was a factor 16–250 compared to the non-periodic simulations. The presented methodology thus serves as a quick screening tool for the development of novel reactor designs and unlocks the potential for using more elaborate kinetic models or a more fundamental approach toward turbulence modeling. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1715–1726, 2017
      PubDate: 2016-10-19T09:40:26.100886-05:
      DOI: 10.1002/aic.15530
  • Bubble/droplet formation and mass transfer during gas–liquid–liquid
           segmented flow with soluble gas in a microchannel
    • Authors: Chaoqun Yao; Yanyan Liu, Shuainan Zhao, Zhengya Dong, Guangwen Chen
      Pages: 1727 - 1739
      Abstract: Microchannels have great potential in intensification of gas–liquid–liquid reactions involving reacting gases, such as hydrogenation. This work uses CO2–octane–water system to model the hydrodynamics and mass transfer of such systems in a microchannel with double T-junctions. Segmented flows are generated with three inlet sequences and the size laws of dispersed phases are obtained. Three generation mechanisms of dispersed gas bubbles/water droplets are identified: squeezing by the oil phase, cutting by the droplet/bubble, cutting by the water–oil/gas–oil interface. Based on the gas dissolution rate, the mass transfer coefficients are calculated. It is found that water droplet can significantly enhance the transfer of CO2 into the oil phase initially. When bubble-droplet cluster are formed downstream the microchannel, droplet will retard the mass transfer. Other characteristics such as phase hold-up, bubble velocity and bubble dissolution rate are also discussed. The information is beneficial for microreactor design when applying three-phase reactions. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1727–1739, 2017
      PubDate: 2016-10-19T11:45:35.247725-05:
      DOI: 10.1002/aic.15536
  • On near-wall jets in a disc-like gas vortex unit
    • Authors: Kaustav Niyogi; Maria M. Torregrosa, Maria N. Pantzali, Geraldine J. Heynderickx, Guy B. Marin, Vladimir N. Shtern
      Pages: 1740 - 1756
      Abstract: To clarify the three-dimensional (3D) structure of near-wall jets observed in disc-like gas vortex units (GVUs), experimental and numerical studies are performed. The experimental results are obtained using stereoscopic particle image velocimetry (PIV), laser doppler anemometry, pressure probes and surface oil flow visualization techniques. The first three techniques have been used to investigate the bulk flow hydrodynamics of the vortex unit. Surface oil flow visualization is adopted to visualize streamlines near the end-walls of the vortex unit. The surface streamlines help to determine the azimuthal and radial velocity components of the radial near-wall jets. Simulations of the vortex unit using FLUENT® v.14a are simultaneously performed, computationally resolving the near-wall jet regions in the axial direction. The simulation results together with the surface oil flow visualization establish the 3D structure of the near-wall jets in GVUs for the first time in literature. It is also conjectured that the near-wall jets develop due to the combined effect of bulk flow acceleration and swirl. The centrifugal force diminishes in the vicinity of the end-walls. The radially inward pressure gradient in these regions, no longer balanced by the centrifugal force, pushes gas radially inward thus developing the near-wall jets. © 2016 The
      Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 63: 1740–1756, 2017
      PubDate: 2016-10-23T16:55:31.760494-05:
      DOI: 10.1002/aic.15533
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