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Publisher: John Wiley and Sons   (Total: 1583 journals)

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Showing 1 - 200 of 1583 Journals sorted alphabetically
Abacus     Hybrid Journal   (Followers: 11, SJR: 0.48, h-index: 22)
About Campus     Hybrid Journal   (Followers: 5)
Academic Emergency Medicine     Hybrid Journal   (Followers: 53, SJR: 1.385, h-index: 91)
Accounting & Finance     Hybrid Journal   (Followers: 43, SJR: 0.547, h-index: 30)
ACEP NOW     Free  
Acta Anaesthesiologica Scandinavica     Hybrid Journal   (Followers: 50, SJR: 1.02, h-index: 88)
Acta Archaeologica     Hybrid Journal   (Followers: 133, SJR: 0.101, h-index: 9)
Acta Geologica Sinica (English Edition)     Hybrid Journal   (Followers: 3, SJR: 0.552, h-index: 41)
Acta Neurologica Scandinavica     Hybrid Journal   (Followers: 5, SJR: 1.203, h-index: 74)
Acta Obstetricia et Gynecologica Scandinavica     Hybrid Journal   (Followers: 15, SJR: 1.197, h-index: 81)
Acta Ophthalmologica     Hybrid Journal   (Followers: 5, SJR: 0.112, h-index: 1)
Acta Paediatrica     Hybrid Journal   (Followers: 54, SJR: 0.794, h-index: 88)
Acta Physiologica     Hybrid Journal   (Followers: 7, SJR: 1.69, h-index: 88)
Acta Polymerica     Hybrid Journal   (Followers: 9)
Acta Psychiatrica Scandinavica     Hybrid Journal   (Followers: 35, SJR: 2.518, h-index: 113)
Acta Zoologica     Hybrid Journal   (Followers: 5, SJR: 0.459, h-index: 29)
Acute Medicine & Surgery     Hybrid Journal   (Followers: 2)
Addiction     Hybrid Journal   (Followers: 32, SJR: 2.086, h-index: 143)
Addiction Biology     Hybrid Journal   (Followers: 12, SJR: 2.091, h-index: 57)
Adultspan J.     Hybrid Journal   (SJR: 0.127, h-index: 4)
Advanced Energy Materials     Hybrid Journal   (Followers: 24, SJR: 6.411, h-index: 86)
Advanced Engineering Materials     Hybrid Journal   (Followers: 24, SJR: 0.81, h-index: 81)
Advanced Functional Materials     Hybrid Journal   (Followers: 47, SJR: 5.21, h-index: 203)
Advanced Healthcare Materials     Hybrid Journal   (Followers: 13, SJR: 0.232, h-index: 7)
Advanced Materials     Hybrid Journal   (Followers: 246, SJR: 9.021, h-index: 345)
Advanced Materials Interfaces     Hybrid Journal   (Followers: 6, SJR: 1.177, h-index: 10)
Advanced Optical Materials     Hybrid Journal   (Followers: 4, SJR: 2.488, h-index: 21)
Advanced Science     Open Access   (Followers: 4)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17, SJR: 2.729, h-index: 121)
Advances in Polymer Technology     Hybrid Journal   (Followers: 13, SJR: 0.344, h-index: 31)
Africa Confidential     Hybrid Journal   (Followers: 19)
Africa Research Bulletin: Economic, Financial and Technical Series     Hybrid Journal   (Followers: 12)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 9)
African Development Review     Hybrid Journal   (Followers: 33, SJR: 0.275, h-index: 17)
African J. of Ecology     Hybrid Journal   (Followers: 14, SJR: 0.477, h-index: 39)
Aggressive Behavior     Hybrid Journal   (Followers: 15, SJR: 1.391, h-index: 66)
Aging Cell     Open Access   (Followers: 9, SJR: 4.374, h-index: 95)
Agribusiness : an Intl. J.     Hybrid Journal   (Followers: 6, SJR: 0.627, h-index: 14)
Agricultural and Forest Entomology     Hybrid Journal   (Followers: 14, SJR: 0.925, h-index: 43)
Agricultural Economics     Hybrid Journal   (Followers: 44, SJR: 1.099, h-index: 51)
AIChE J.     Hybrid Journal   (Followers: 28, SJR: 1.122, h-index: 120)
Alcoholism and Drug Abuse Weekly     Hybrid Journal   (Followers: 7)
Alcoholism Clinical and Experimental Research     Hybrid Journal   (Followers: 7, SJR: 1.416, h-index: 125)
Alimentary Pharmacology & Therapeutics     Hybrid Journal   (Followers: 33, SJR: 2.833, h-index: 138)
Alimentary Pharmacology & Therapeutics Symposium Series     Hybrid Journal   (Followers: 3)
Allergy     Hybrid Journal   (Followers: 49, SJR: 3.048, h-index: 129)
Alternatives to the High Cost of Litigation     Hybrid Journal   (Followers: 3)
American Anthropologist     Hybrid Journal   (Followers: 128, SJR: 0.951, h-index: 61)
American Business Law J.     Hybrid Journal   (Followers: 24, SJR: 0.205, h-index: 17)
American Ethnologist     Hybrid Journal   (Followers: 89, SJR: 2.325, h-index: 51)
American J. of Economics and Sociology     Hybrid Journal   (Followers: 28, SJR: 0.211, h-index: 26)
American J. of Hematology     Hybrid Journal   (Followers: 30, SJR: 1.761, h-index: 77)
American J. of Human Biology     Hybrid Journal   (Followers: 12, SJR: 1.018, h-index: 58)
American J. of Industrial Medicine     Hybrid Journal   (Followers: 16, SJR: 0.993, h-index: 85)
American J. of Medical Genetics Part A     Hybrid Journal   (Followers: 15, SJR: 1.115, h-index: 61)
American J. of Medical Genetics Part B: Neuropsychiatric Genetics     Hybrid Journal   (Followers: 3, SJR: 1.771, h-index: 107)
American J. of Medical Genetics Part C: Seminars in Medical Genetics     Partially Free   (Followers: 5, SJR: 2.315, h-index: 79)
American J. of Orthopsychiatry     Hybrid Journal   (Followers: 4, SJR: 0.756, h-index: 69)
American J. of Physical Anthropology     Hybrid Journal   (Followers: 35, SJR: 1.41, h-index: 88)
American J. of Political Science     Hybrid Journal   (Followers: 236, SJR: 5.101, h-index: 114)
American J. of Primatology     Hybrid Journal   (Followers: 14, SJR: 1.197, h-index: 63)
American J. of Reproductive Immunology     Hybrid Journal   (Followers: 3, SJR: 1.347, h-index: 75)
American J. of Transplantation     Hybrid Journal   (Followers: 15, SJR: 2.792, h-index: 140)
American J. on Addictions     Hybrid Journal   (Followers: 9, SJR: 0.843, h-index: 57)
Anaesthesia     Hybrid Journal   (Followers: 115, SJR: 1.404, h-index: 88)
Analyses of Social Issues and Public Policy     Hybrid Journal   (Followers: 11, SJR: 0.397, h-index: 18)
Analytic Philosophy     Hybrid Journal   (Followers: 15)
Anatomia, Histologia, Embryologia: J. of Veterinary Medicine Series C     Hybrid Journal   (Followers: 3, SJR: 0.295, h-index: 27)
Anatomical Sciences Education     Hybrid Journal   (Followers: 1, SJR: 0.633, h-index: 24)
Andrologia     Hybrid Journal   (Followers: 2, SJR: 0.528, h-index: 45)
Andrology     Hybrid Journal   (Followers: 2, SJR: 0.979, h-index: 14)
Angewandte Chemie     Hybrid Journal   (Followers: 152)
Angewandte Chemie Intl. Edition     Hybrid Journal   (Followers: 204, SJR: 6.229, h-index: 397)
Animal Conservation     Hybrid Journal   (Followers: 34, SJR: 1.576, h-index: 62)
Animal Genetics     Hybrid Journal   (Followers: 8, SJR: 0.957, h-index: 67)
Animal Science J.     Hybrid Journal   (Followers: 5, SJR: 0.569, h-index: 24)
Annalen der Physik     Hybrid Journal   (Followers: 5, SJR: 1.46, h-index: 40)
Annals of Anthropological Practice     Partially Free   (Followers: 2, SJR: 0.187, h-index: 5)
Annals of Applied Biology     Hybrid Journal   (Followers: 8, SJR: 0.816, h-index: 56)
Annals of Clinical and Translational Neurology     Open Access   (Followers: 1)
Annals of Human Genetics     Hybrid Journal   (Followers: 9, SJR: 1.191, h-index: 67)
Annals of Neurology     Hybrid Journal   (Followers: 42, SJR: 5.584, h-index: 241)
Annals of Noninvasive Electrocardiology     Hybrid Journal   (Followers: 2, SJR: 0.531, h-index: 38)
Annals of Public and Cooperative Economics     Hybrid Journal   (Followers: 9, SJR: 0.336, h-index: 23)
Annals of the New York Academy of Sciences     Hybrid Journal   (Followers: 5, SJR: 2.389, h-index: 189)
Annual Bulletin of Historical Literature     Hybrid Journal   (Followers: 12)
Annual Review of Information Science and Technology     Hybrid Journal   (Followers: 14)
Anthropology & Education Quarterly     Hybrid Journal   (Followers: 24, SJR: 0.72, h-index: 31)
Anthropology & Humanism     Hybrid Journal   (Followers: 16, SJR: 0.137, h-index: 3)
Anthropology News     Hybrid Journal   (Followers: 14)
Anthropology of Consciousness     Hybrid Journal   (Followers: 11, SJR: 0.172, h-index: 5)
Anthropology of Work Review     Hybrid Journal   (Followers: 11, SJR: 0.256, h-index: 5)
Anthropology Today     Hybrid Journal   (Followers: 92, SJR: 0.545, h-index: 15)
Antipode     Hybrid Journal   (Followers: 45, SJR: 2.212, h-index: 69)
Anz J. of Surgery     Hybrid Journal   (Followers: 6, SJR: 0.432, h-index: 59)
Anzeiger für Schädlingskunde     Hybrid Journal   (Followers: 1)
Apmis     Hybrid Journal   (Followers: 1, SJR: 0.855, h-index: 73)
Applied Cognitive Psychology     Hybrid Journal   (Followers: 66, SJR: 0.754, h-index: 69)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 6, SJR: 0.632, h-index: 58)
Applied Psychology     Hybrid Journal   (Followers: 127, SJR: 1.023, h-index: 64)
Applied Psychology: Health and Well-Being     Hybrid Journal   (Followers: 47, SJR: 0.868, h-index: 13)
Applied Stochastic Models in Business and Industry     Hybrid Journal   (Followers: 5, SJR: 0.613, h-index: 24)
Aquaculture Nutrition     Hybrid Journal   (Followers: 13, SJR: 1.025, h-index: 55)
Aquaculture Research     Hybrid Journal   (Followers: 31, SJR: 0.807, h-index: 60)
Aquatic Conservation Marine and Freshwater Ecosystems     Hybrid Journal   (Followers: 34, SJR: 1.047, h-index: 57)
Arabian Archaeology and Epigraphy     Hybrid Journal   (Followers: 11, SJR: 0.453, h-index: 11)
Archaeological Prospection     Hybrid Journal   (Followers: 12, SJR: 0.922, h-index: 21)
Archaeology in Oceania     Hybrid Journal   (Followers: 13, SJR: 0.745, h-index: 18)
Archaeometry     Hybrid Journal   (Followers: 27, SJR: 0.809, h-index: 48)
Archeological Papers of The American Anthropological Association     Hybrid Journal   (Followers: 14, SJR: 0.156, h-index: 2)
Architectural Design     Hybrid Journal   (Followers: 24, SJR: 0.261, h-index: 9)
Archiv der Pharmazie     Hybrid Journal   (Followers: 4, SJR: 0.628, h-index: 43)
Archives of Drug Information     Hybrid Journal   (Followers: 4)
Archives of Insect Biochemistry and Physiology     Hybrid Journal   (SJR: 0.768, h-index: 54)
Area     Hybrid Journal   (Followers: 12, SJR: 0.938, h-index: 57)
Art History     Hybrid Journal   (Followers: 203, SJR: 0.153, h-index: 13)
Arthritis & Rheumatology     Hybrid Journal   (Followers: 48, SJR: 1.984, h-index: 20)
Arthritis Care & Research     Hybrid Journal   (Followers: 27, SJR: 2.256, h-index: 114)
Artificial Organs     Hybrid Journal   (Followers: 1, SJR: 0.872, h-index: 60)
ASHE Higher Education Reports     Hybrid Journal   (Followers: 13)
Asia & the Pacific Policy Studies     Open Access   (Followers: 15)
Asia Pacific J. of Human Resources     Hybrid Journal   (Followers: 319, SJR: 0.494, h-index: 19)
Asia Pacific Viewpoint     Hybrid Journal   (SJR: 0.616, h-index: 26)
Asia-Pacific J. of Chemical Engineering     Hybrid Journal   (Followers: 7, SJR: 0.345, h-index: 20)
Asia-pacific J. of Clinical Oncology     Hybrid Journal   (Followers: 6, SJR: 0.554, h-index: 14)
Asia-Pacific J. of Financial Studies     Hybrid Journal   (SJR: 0.241, h-index: 7)
Asia-Pacific Psychiatry     Hybrid Journal   (Followers: 3, SJR: 0.377, h-index: 7)
Asian Economic J.     Hybrid Journal   (Followers: 8, SJR: 0.234, h-index: 21)
Asian Economic Policy Review     Hybrid Journal   (Followers: 3, SJR: 0.196, h-index: 12)
Asian J. of Control     Hybrid Journal   (SJR: 0.862, h-index: 34)
Asian J. of Endoscopic Surgery     Hybrid Journal   (SJR: 0.394, h-index: 7)
Asian J. of Organic Chemistry     Hybrid Journal   (Followers: 4, SJR: 1.443, h-index: 19)
Asian J. of Social Psychology     Hybrid Journal   (Followers: 5, SJR: 0.665, h-index: 37)
Asian Politics and Policy     Hybrid Journal   (Followers: 13, SJR: 0.207, h-index: 7)
Asian Social Work and Policy Review     Hybrid Journal   (Followers: 5, SJR: 0.318, h-index: 5)
Asian-pacific Economic Literature     Hybrid Journal   (Followers: 5, SJR: 0.168, h-index: 15)
Assessment Update     Hybrid Journal   (Followers: 4)
Astronomische Nachrichten     Hybrid Journal   (Followers: 2, SJR: 0.701, h-index: 40)
Atmospheric Science Letters     Open Access   (Followers: 29, SJR: 1.332, h-index: 27)
Austral Ecology     Hybrid Journal   (Followers: 12, SJR: 1.095, h-index: 66)
Austral Entomology     Hybrid Journal   (Followers: 10, SJR: 0.524, h-index: 28)
Australasian J. of Dermatology     Hybrid Journal   (Followers: 7, SJR: 0.714, h-index: 40)
Australasian J. On Ageing     Hybrid Journal   (Followers: 7, SJR: 0.39, h-index: 22)
Australian & New Zealand J. of Statistics     Hybrid Journal   (Followers: 13, SJR: 0.275, h-index: 28)
Australian Accounting Review     Hybrid Journal   (Followers: 3, SJR: 0.709, h-index: 14)
Australian and New Zealand J. of Family Therapy (ANZJFT)     Hybrid Journal   (Followers: 3, SJR: 0.382, h-index: 12)
Australian and New Zealand J. of Obstetrics and Gynaecology     Hybrid Journal   (Followers: 42, SJR: 0.814, h-index: 49)
Australian and New Zealand J. of Public Health     Hybrid Journal   (Followers: 11, SJR: 0.82, h-index: 62)
Australian Dental J.     Hybrid Journal   (Followers: 6, SJR: 0.482, h-index: 46)
Australian Economic History Review     Hybrid Journal   (Followers: 4, SJR: 0.171, h-index: 12)
Australian Economic Papers     Hybrid Journal   (Followers: 22, SJR: 0.23, h-index: 9)
Australian Economic Review     Hybrid Journal   (Followers: 6, SJR: 0.357, h-index: 21)
Australian Endodontic J.     Hybrid Journal   (Followers: 3, SJR: 0.513, h-index: 24)
Australian J. of Agricultural and Resource Economics     Hybrid Journal   (Followers: 3, SJR: 0.765, h-index: 36)
Australian J. of Grape and Wine Research     Hybrid Journal   (Followers: 5, SJR: 0.879, h-index: 56)
Australian J. of Politics & History     Hybrid Journal   (Followers: 13, SJR: 0.203, h-index: 14)
Australian J. of Psychology     Hybrid Journal   (Followers: 16, SJR: 0.384, h-index: 30)
Australian J. of Public Administration     Hybrid Journal   (Followers: 383, SJR: 0.418, h-index: 29)
Australian J. of Rural Health     Hybrid Journal   (Followers: 4, SJR: 0.43, h-index: 34)
Australian Occupational Therapy J.     Hybrid Journal   (Followers: 64, SJR: 0.59, h-index: 29)
Australian Psychologist     Hybrid Journal   (Followers: 11, SJR: 0.331, h-index: 31)
Australian Veterinary J.     Hybrid Journal   (Followers: 19, SJR: 0.459, h-index: 45)
Autism Research     Hybrid Journal   (Followers: 31, SJR: 2.126, h-index: 39)
Autonomic & Autacoid Pharmacology     Hybrid Journal   (SJR: 0.371, h-index: 29)
Banks in Insurance Report     Hybrid Journal   (Followers: 1)
Basic & Clinical Pharmacology & Toxicology     Hybrid Journal   (Followers: 9, SJR: 0.539, h-index: 70)
Basic and Applied Pathology     Open Access   (Followers: 2, SJR: 0.113, h-index: 4)
Basin Research     Hybrid Journal   (Followers: 3, SJR: 1.54, h-index: 60)
Bauphysik     Hybrid Journal   (Followers: 2, SJR: 0.194, h-index: 5)
Bauregelliste A, Bauregelliste B Und Liste C     Hybrid Journal  
Bautechnik     Hybrid Journal   (Followers: 1, SJR: 0.321, h-index: 11)
Behavioral Interventions     Hybrid Journal   (Followers: 7, SJR: 0.297, h-index: 23)
Behavioral Sciences & the Law     Hybrid Journal   (Followers: 21, SJR: 0.736, h-index: 57)
Berichte Zur Wissenschaftsgeschichte     Hybrid Journal   (Followers: 9, SJR: 0.11, h-index: 5)
Beton- und Stahlbetonbau     Hybrid Journal   (Followers: 2, SJR: 0.493, h-index: 14)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 6, SJR: 0.311, h-index: 26)
Bioelectromagnetics     Hybrid Journal   (Followers: 1, SJR: 0.568, h-index: 64)
Bioengineering & Translational Medicine     Open Access  
BioEssays     Hybrid Journal   (Followers: 10, SJR: 3.104, h-index: 155)
Bioethics     Hybrid Journal   (Followers: 14, SJR: 0.686, h-index: 39)
Biofuels, Bioproducts and Biorefining     Hybrid Journal   (Followers: 1, SJR: 1.725, h-index: 56)
Biological J. of the Linnean Society     Hybrid Journal   (Followers: 14, SJR: 1.172, h-index: 90)
Biological Reviews     Hybrid Journal   (Followers: 2, SJR: 6.469, h-index: 114)
Biologie in Unserer Zeit (Biuz)     Hybrid Journal   (Followers: 44, SJR: 0.12, h-index: 1)
Biology of the Cell     Full-text available via subscription   (Followers: 9, SJR: 1.812, h-index: 69)
Biomedical Chromatography     Hybrid Journal   (Followers: 6, SJR: 0.572, h-index: 49)
Biometrical J.     Hybrid Journal   (Followers: 5, SJR: 0.784, h-index: 44)
Biometrics     Hybrid Journal   (Followers: 37, SJR: 1.906, h-index: 96)
Biopharmaceutics and Drug Disposition     Hybrid Journal   (Followers: 10, SJR: 0.715, h-index: 44)
Biopolymers     Hybrid Journal   (Followers: 18, SJR: 1.199, h-index: 104)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 45, SJR: 0.415, h-index: 55)
Biotechnology and Bioengineering     Hybrid Journal   (Followers: 134, SJR: 1.633, h-index: 146)
Biotechnology J.     Hybrid Journal   (Followers: 13, SJR: 1.185, h-index: 51)
Biotechnology Progress     Hybrid Journal   (Followers: 39, SJR: 0.736, h-index: 101)
Biotropica     Hybrid Journal   (Followers: 17, SJR: 1.374, h-index: 71)
Bipolar Disorders     Hybrid Journal   (Followers: 10, SJR: 2.592, h-index: 100)
Birth     Hybrid Journal   (Followers: 33, SJR: 0.763, h-index: 64)
Birth Defects Research Part A : Clinical and Molecular Teratology     Hybrid Journal   (Followers: 2, SJR: 0.727, h-index: 77)
Birth Defects Research Part B: Developmental and Reproductive Toxicology     Hybrid Journal   (Followers: 5, SJR: 0.468, h-index: 47)
Birth Defects Research Part C : Embryo Today : Reviews     Hybrid Journal   (SJR: 1.513, h-index: 55)

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Journal Cover AIChE Journal
  [SJR: 1.122]   [H-I: 120]   [28 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0001-1541 - ISSN (Online) 1547-5905
   Published by John Wiley and Sons Homepage  [1583 journals]
  • Indirect Conduction in Gas-Solids Systems: Static vs. Dynamic Effects
    • Authors: Aaron M. Lattanzi; Christine M. Hrenya
      Abstract: Conductive mechanisms play an integral role in the transfer of heat through dense gas-solid systems. In particular, the conduction occurring through a thin layer of fluid between the solids (indirect) can become the primary mode for heat transfer within gas-solid systems. However, attempts to evaluate the effect of surface roughness and fluid lens thickness (theoretical inputs) on indirect conduction have been restricted to static, single-particle cases. By contrast, here we quantify these effects for dynamic, multi-particle systems using a non-dimensional, average heat transfer coefficient that is obtained via techniques commonly employed by classic kinetic theory. Analytical predictions for the impact of theoretical inputs on indirect conduction are compared to outputs from computational fluid dynamics – discrete element method simulations. The analytical predictions are in agreement with simulations and show that indirect conduction in static systems is most sensitive to surface roughness, while dynamic systems are sensitive to the fluid lens thickness. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-23T04:55:30.680415-05:
      DOI: 10.1002/aic.15802
       
  • Particle-Laden Liquid Jet Impingement On A Moving Substrate
    • Authors: Hatef Rahmani; Sheldon I. Green
      Abstract: The impingement of high speed jets on a moving surface was studied. The jet fluids were dilute suspensions of neutrally buoyant particles in water-glycerin solutions. At these low particle concentrations, the suspensions have Newtonian fluid viscosity. A variety of jet and surface velocities, solution properties, nozzle diameters, mean particle sizes, and volume fractions were studied. For each case the splash-deposition threshold was quantified. It was observed that for jets with very small particles, addition of solids to the jet enhances deposition and postpones splash relative to a particle-free water-glycerin solution with the same viscosity. In contrast, jets with larger particles in suspension were more prone to splash than single phase jets of the same viscosity. It is speculated that the change in character of the splash response for the jets with larger particles in suspension occurs when the particle diameter is comparable to the lamella thickness. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-23T04:55:29.523336-05:
      DOI: 10.1002/aic.15800
       
  • Mixing dynamics in bubbling fluidized beds
    • Authors: A. Bakshi; C. Altantzis, A.F. Ghoniem
      Abstract: Solids mixing affects thermal and concentration gradients in fluidized bed reactors and is, therefore, critical to their performance. Despite substantial effort over the past decades, understanding of solids mixing continues to be lacking because of technical limitations of diagnostics in large pilot and commercial-scale reactors. This study is focused on investigating mixing dynamics and their dependence on operating conditions using CFD simulations. Towards this end, fine-grid 3D simulations are conducted for the bubbling fluidization of three distinct Geldart B particles (1.15 mm LLDPE, 0.50 mm glass and 0.29 mm alumina) at superficial gas velocities U/Umf =2-4 in a pilot-scale 50 cm diameter bed. The Two-Fluid Model (TFM) is employed to describe the solids motion efficiently while bubbles are detected and tracked using MS3DATA. Detailed statistics of the flow-field in and around bubbles are computed and used to describe bubble-induced solids micromixing: solids upflow driven in the nose and wake regions while downflow along the bubble walls. Further, within these regions, the hydrodynamics are dependent only on particle and bubble characteristics, and relatively independent of the global operating conditions. Based on this finding, a predictive mechanistic, analytical model is developed which integrates bubble-induced micromixing contributions over their size and spatial distributions to describe the gross solids circulation within the fluidized bed. Finally, it is shown that solids mixing is affected adversely in the presence of gas bypass, or throughflow, particularly in the fluidization of heavier particles. This is because of inefficient gas solids contacting as 30-50% of the superficial gas flow escapes with 2-3× shorter residence time through the bed. This is one of the first large-scale studies where both the gas (bubble) and solids motion, and their interaction, are investigated in detail and the developed framework is useful for predicting solids mixing in large-scale reactors as well as for analyzing mixing dynamics in complex reactive particulate systems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-23T04:55:22.432144-05:
      DOI: 10.1002/aic.15801
       
  • Time-resolved ultrasonic spectroscopy for bubbles
    • Authors: Valentin Leroy; Anatoliy Strybulevych, Tomohisa Norisuye
      Abstract: We show that ultrasound can provide time-resolved measurements of the sizes distribution and the concentration of bubbles in a liquid. The potential of the technique is demonstrated by following disappearance of bubbles having an average radius of 20 µm with a 10 ms time resolution. We show that our technique can detect small concentrations of bubbles, with a large spectrum of accessible bubble radii (from 80 nm to 40 µm for a gas volume fraction of 10-5), and with a sub-millisecond time resolution. This new technique could be a valuable tool for investigating rapid processes such as nucleation or dissolution of bubbles. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-19T07:16:08.820515-05:
      DOI: 10.1002/aic.15799
       
  • A Green Process for Recovery of H2SO4 and Fe2O3 from FeSO4·7H2O by
           Modeling Phase Equilibrium of the Fe(П)‒SO42‒‒H+‒Cl‒ System
    • Authors: Yan Zhang; Zhibao Li, Yan Zeng, George P. Demopoulos
      Abstract: Ferrous sulfate heptahydrate FeSO4·7H2O is a major waste produced in titanium dioxide industry by the sulfate process and has caused heavy environmental problem. A new green process for the treatment of FeSO4·7H2O was proposed to make use of iron source and recycle sulfate source as H2SO4. It was found that by adding concentrated HCl to the FeSO4 solution, FeCl2·4H2O was crystallized out, which was subsequently calcined to produce Fe2O3 and HCl. Concentrated H2SO4 solution (about 65 wt%) was obtained by evaporating the FeCl2·4H2O-saturated filtrate. To facilitate the process development and design, the solubilities of FeCl2·4H2O in HCl, H2SO4, and HCl+H2SO4 solutions were measured and the experimental data were regressed with both the mixed-solvent electrolyte (MSE) model and the electrolyte NRTL model. On the basis of the prediction of the optimum conditions for the crystallization of FeCl2·4H2O, material balance of the new process was calculated. FeCl2·4H2O and Fe2O3 were obtained from a laboratory-scale test with about 70% recovery of ferrous source for a single cycle, indicating the feasibility of the process. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-19T06:15:32.86278-05:0
      DOI: 10.1002/aic.15795
       
  • Modeling of CO2 Equilibrium Solubility in a Novel
           1-diethylamino-2-Propanol Solvent
    • Authors: Helei Liu; Min Xiao, Xiao Luo, Hongxia Gao, Raphael Idem, Paitoon Tontiwachwuthikul, Zhiwu Liang
      Abstract: In this work, the equilibrium solubility of CO2 in a 1-diethylamino-2-propanol (1DEA2P) solution was determined as a function of 1DEA2P concentration (over the range of 1-2M), temperature (in the range of 298-333K), and CO2 partial pressure (in the range of 8-101kPa). These experimental results were used to fit the present correlation for K2 (Kent-Eisenberg model, Austgen model, and Li-Shen model). It was found that all of the models could represent the CO2 equilibrium solubility in 1DEA2P solution with ADDs for Kent-Eisenberg model, Austgen model, and Li-Shen model of 6.3%, 7.3% and 12.2%, respectively. A new K2 correlation model, the Liu-Helei model, was also developed to predict the CO2 equilibrium solubility in 1DEA2P solution with an excellent ADD of 3.4%. In addition, the heat of absorption of CO2 in 1DEA2P solution estimated by using the Gibbs-Helmholtz equation was found to be -45.7±3.7 kJ/mol. Information and guidelines about effectively using data for screened solvents is also provided based on the three absorption parameters: CO2 equilibrium solubility, second order reaction constant (k2), and CO2 absorption heat. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-19T05:50:38.187229-05:
      DOI: 10.1002/aic.15797
       
  • Effects of Protein Properties on Adsorption and Transport in
           Polymer-grafted Ion Exchangers: A Multiscale Modeling Study
    • Authors: Joseph E. Basconi; Giorgio Carta, Michael R. Shirts
      Abstract: We use multiscale modeling to study how the molecular properties of a protein affect its adsorption and transport in ion exchange (IEX) chromatography matrices with either open pores or charged polymers grafted into the pore structure. Coarse-grained molecular dynamics (MD) simulations of lysozyme, bovine serum albumin (BSA), and immunoglobulin (IgG) show that higher protein net charge leads to greater partitioning into the polymer-grafted pore space but slower diffusion there due to favorable electrostatic interactions, while larger size decreases both pore space partitioning and diffusion due to steric effects of the polymers. Mass transfer simulations based on the MD results show that the polymer-grafted systems can enhance the adsorption kinetics if pore space partitioning and diffusion are both sufficiently high. The simulations illustrate that to achieve fast adsorption kinetics, there is a tradeoff between favorable binding and rapid diffusion which largely depends on the charge and size of the protein. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-19T05:35:25.086719-05:
      DOI: 10.1002/aic.15798
       
  • MnOx Promotional Effects on Olefins Synthesis Directly from Syngas over
           Bimetallic Fe-MnOx/SiO2 Catalysts
    • Authors: Zhengpai Zhang; Weiwei Dai, Xin-Chao Xu, Jun Zhang, Bianfang Shi, Jing Xu, Weifeng Tu, Yi-Fan Han
      Abstract: The direct synthesis of lower olefins via the Fischer-Tropsch reaction (FTO) has been performed over a series of Fe-MnOx/SiO2 catalysts. The addition of MnOx could improve the dispersion of iron species, and promote the reduction of iron oxide during the activation and subsequent carburization. Moreover, the results of characterization demonstrated that MnOx could enhance the surface basicity of the catalysts due to electronic effects and promote the formation of iron carbides. For the first time, the intrinsic power-law kinetics for FTO was obtained for both Fe20/SiO2 and Fe20-Mn1/SiO2 catalysts. Kinetic parameters and structure characterizations indicated that MnOx could facilitate the CO dissociation on the catalyst surface, thus enhancing the adsorption strength and capacity of surface carbonaceous intermediates. The weak hydrogenation of carbonaceous species would boost the selectivities toward lower olefins. Finally, a plausible mechanism for FTO, involving the promotional effects of MnOx on Fe, has been proposed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-18T07:23:07.855747-05:
      DOI: 10.1002/aic.15796
       
  • Magnetohydrodynamics thin film fluid flow under the effect of
           thermophoresis and variable fluid properties
    • Authors: L Ali; I Saeed, T Gul, A Alshomrani, I Khan, K Aurangzeb
      Abstract: The thin film flow of fluid over a stretching sheet with variable fluid properties under the effect of thermophoresis has been investigated. A transverse magnetic field is also applied to the fluid flow in the presence of thermal radiation. The governing equations have been transformed through suitable similarity variables into nonlinear coupled differential equations with physical conditions. The solution of the coupled problem has been obtained by using the second alternative of OHAM (OHAM-2). The solution of the coupled problem through this new method and its fast convergence is mainly focused in this work. The effect of physical parameters appears in the problem are shown graphically and discussed. Finally, the obtained results are compared with a numerical (ND-Solve) method to authenticate the code of the OHAM-2. The physical and numerical agreement of these two methods has been shown. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-18T07:05:26.299711-05:
      DOI: 10.1002/aic.15794
       
  • Simulation of Deformable Preformed Particle Gel Propagation in Porous
           Media
    • Authors: Jing Wang; Hui-qing Liu, Hong-ling Zhang, Kamy Sepehrnoori
      Abstract: Preformed particle gel (PPG) treatment is a proven cost-effective method for improving oil recovery. Although PPG system has a suspension-like property, it has different propagation rules from the rigid particle suspension in porous media because of its good deformation property. In this study, an advanced phenomenological model of PPG propagation in porous media is presented. The model includes both PPG plugging and restarting behaviors. Log-normal and normal distribution functions have been introduced in this model to calculate the PPG plugging probability. Power-law equation is used to calculate the PPG restarting rate. This method can represent the commensurate relation between PPG and throat size. Then, the equations are solved numerically, using an explicit finite-difference formulation in conjunction with a fourth-order Runge-Kutta method. The results match favorably with several laboratory experiments. Finally, the propagation rules and sensitivity analysis of PPG size, permeability and injection rate to propagation rules, and permeability reduction are performed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-16T04:40:43.104119-05:
      DOI: 10.1002/aic.15793
       
  • NMR Spectroscopic Study of Chemical Equilibria in Solutions of
           Formaldehyde, Water, and Butynediol
    • Authors: Jürgen Berje; Jens Baldamus, Jakob Burger, Hans Hasse
      Abstract: Liquid mixtures of formaldehyde, water, and butynediol are complex reacting multicomponent systems in which formaldehyde forms oligomers both with water and butynediol. 1H - and 13C -NMR spectra of these mixtures are elucidated. The species distribution of the oligomers is quantitatively determined by 13C -NMR spectroscopy. The measurements cover temperatures from 293 K to 366 K, overall formaldehyde mass fractions from 0.10gg-1 to 0.27gg-1, and overall butynediol mass fractions from 0.05gg-1 to 0.50gg-1. A mole fraction-based and an activity-based model of the chemical equilibrium in the studied system are developed and chemical equilibrium constants are reported. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:46:44.52981-05:0
      DOI: 10.1002/aic.15788
       
  • Distributed Output-Feedback Fault Detection and Isolation of Cascade
           Process Networks
    • Authors: Xunyuan Yin; Jinfeng Liu
      Abstract: In this work, we consider distributed output-feedback fault detection and isolation (FDI) of nonlinear cascade process networks that can be divided into subsystems. Based on the assumption that an exponentially convergent estimator exists for each subsystem, a distributed state estimation system is developed. In the distributed state estimation system, a compensator is designed for each subsystem to compensate for subsystem interaction and the estimators for subsystems communicate to exchange information. It is shown that when there is no fault, the estimation error of the distributed estimation system converges to zero in the absence of system disturbances and measurement noise. For each subsystem, a state predictor is also designed to provide subsystem state predictions. A residual generator is designed for each subsystem based on subsystem state estimates given by the distributed state estimation system and subsystem state predictions given by the predictor. A subsystem residual generator generates two residual sequences, which act as references for FDI. A distributed FDI mechanism is proposed based on residuals. The proposed approach is able to handle both actuator faults and sensor faults by evaluating the residual signals. A chemical process example is introduced to demonstrate the effectiveness of the distributed FDI mechanism. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:46:39.096694-05:
      DOI: 10.1002/aic.15791
       
  • Accurate thermodynamic modeling of ionic liquids/metal salt mixtures:
           Application to carbon monoxide reactive absorption
    • Authors: Gabriel Zarca; Inmaculada Ortiz, Ane Urtiaga, Fèlix Llovell
      Abstract: For the first time, a theoretical semi-predictive approach based on the soft-SAFT equation of state is presented to model the complexation reaction between carbon monoxide (CO) in a combined ionic liquid (IL) plus a copper(I) metallic salt media in terms of the gas solubility as a function of temperature, pressure and composition. Two different degrees of molecular approximation are tested. In the first approach, the IL-metal salt mixture is treated as a single compound whose parameters are modified according to the concentration of the metallic salt. In the second approach, both compounds are treated as independent species, enhancing the predictive capability of the model. The complexation between CO molecules and the metal salt is reproduced by adding specific cross-association interaction sites that simulate the reaction. The density of the doped IL and the CO solubility are described in quantitative agreement with the experimental data at different operating conditions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:46:30.025594-05:
      DOI: 10.1002/aic.15790
       
  • Capillary Driven Flow in Wettability altered Microchannel
    • Authors: Ayantika Sett; Uzma Bano, Debasish Sarkar, Arijit Mitra, Siddhartha Das, Swagata Dasgupta, Sunando DasGupta
      Abstract: The capillary driven flow of water inside a microchannel with altered wettabilities is experimentally investigated and modelled theoretically. The surfaces of the PDMS made microchannel are exposed to oxygen plasma, rendering the surfaces increasingly hydrophilic, which provides the driving force for the flow. The plasma treated surfaces are characterized using topography and phase imaging of AFM scanning, as well as nano-indentation, to correlate the distinct structural changes to the hydrodynamic profiles of the advancing meniscus. The experimental results are further analyzed using a newly-proposed slip velocity model. The aim is to obtain a qualitative relationship between the surface properties and the flow parameters, namely the advancing meniscus velocity and pressure drop inside the channel. The insights are of fundamental importance in diverse fields, such as enhanced oil recovery, microfluidic devices, cell separation and pathology. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:46:16.652557-05:
      DOI: 10.1002/aic.15787
       
  • A Data-Driven Multistage Adaptive Robust Optimization Framework for
           Planning and Scheduling under Uncertainty
    • Authors: Chao Ning; Fengqi You
      Abstract: We propose a novel data-driven approach for optimization under uncertainty based on multistage adaptive robust optimization (ARO) and nonparametric kernel density M-estimation. Different from conventional robust optimization methods, the proposed framework incorporates distributional information to avoid over-conservatism. Robust kernel density estimation with Hampel loss function is employed to extract probability distributions from uncertainty data via a kernelized iteratively re-weighted least squares algorithm. A data-driven uncertainty set is proposed, where bounds of uncertain parameters are defined by quantile functions, in order to organically integrate the multistage ARO framework with uncertainty data. Based on this uncertainty set, we further develop an exact robust counterpart in its general form for solving the resulting data-driven multistage ARO problem. To illustrate the applicability of the proposed framework, two typical applications in process operations are presented: The first one is on strategic planning of process networks, and the other one on short-term scheduling of multipurpose batch processes. The proposed approach returns 23.9% higher net present value and 31.5% more profits than the conventional robust optimization method in planning and scheduling applications, respectively. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:46:05.143171-05:
      DOI: 10.1002/aic.15792
       
  • PEI-grafted Membranes for Simultaneously Adsorbing Heavy Metal Ions and
           Rejecting Suspended Particles in Wastewater
    • Authors: Xuehua Ruan; Yan Xu, Xuhang Liao, Gaohong He, Xiaoming Yan, Yan Dai, Ning Zhang, Lin Du
      Abstract: Heavy metal ions (HMIs) in wastewater can be removed by polyethyleneimine (PEI) adsorption, however, it is difficult to recycle PEI macromolecules from their mixture with suspended particles in wastewater. A novel HMIs adsorption technique with renewable PEI-grafted porous membranes was developed. PEI molecules were dispersed with high specific area and structured morphology, which allowed HMIs and suspended particles to be retained separately at different locations of the membrane, with the former adsorbed in matrix and the latter rejected on surface. The membranes with the optimized PEI loading ratio of 30wt% behaved excellently with microsphere rejection and Co(II) adsorption reaching 98.5% and 51.0mg/g, respectively. They successfully decreased Co(II) concentration from 3.0mg/L to the allowable discharge standard (0.5mg/L), even with an enhanced flux of 6200L/m2/h at 0.12MPa under the cyclic tests. Overall, PEI-grafted membrane adsorption is highly efficient for removing HMIs and suspended particles simultaneously from wastewater. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:45:47.841511-05:
      DOI: 10.1002/aic.15789
       
  • A Cobalt Metal-Organic Framework with Small Pore Size for Adsorptive
           Separation of CO2 over N2 and CH4
    • Authors: Bohan Shan; Jiuhao Yu, Mitchell R. Armstrong, Dingke Wang, Zhenfei Cheng, Jichang Liu, Bin Mu
      Abstract: In this study, a new cobalt-based metal-organic framework (MOF), [CoII6(μ3-OH)2(ipa)5(C3O2)(DMF)2] (CoIPA) was synthesized. The crystal structure analysis shows that CoIPA is constructed by Co6(μ3-OH)2 units linked by isophthalic acid forming a sxb topology and it possesses a small pore size of about 4 Å. The new MOF has been characterized using multiple experimental methods. Monte Carlo and Molecular Dynamic simulations were employed to investigate adsorption equilibrium and kinetics in terms of capacity and diffusivity of CO2, N2, and CH4 on CoIPA. The gas adsorption isotherms collected experimentally were used to verify the simulation results. The activated CoIPA sample exhibits great gas separation ability at ambient conditions for CO2/N2 and CO2/CH4 with selectivity of around 61.4 and 11.7, respectively. The calculated self-diffusion coefficients show a strong direction dependent diffusion behavior of target molecules. This high adsorption selectivity for both CO2/N2 and CO2/CH4 makes CoIPA a potential candidate for adsorptive CO2 separation. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-11T18:35:32.961171-05:
      DOI: 10.1002/aic.15786
       
  • Modeling and Process Simulation of Hollow Fiber Membrane Reactor Systems
           for Propane Dehydrogenation
    • Authors: Seung-Won Choi; Jason S. Moore, Yujun Liu, Ravindra S. Dixit, John G. Pendergast, David S. Sholl, Sankar Nair
      Abstract: We report a detailed modeling analysis of membrane reactor systems for propane dehydrogenation (PDH) by integrating a two-dimensional (2D) non-isothermal model of a packed bed membrane reactor (PBMR) with ASPEN process simulations for the overall PDH plant including downstream separations processes. PBMRs based upon ceramic hollow fiber membranes - with catalyst placement on the shell side - are found to be a viable route, whereas conventional tubular membranes are prohibitively expensive. The overall impact of the PBMR on the PDH plant (e.g., required dimensions, catalyst amount, overall energy use in reaction and downstream separation) is determined. Large savings in overall energy use and catalyst amounts can be achieved with an appropriate configuration of PBMR stages and optimal sweep/feed ratio. Overall, this work determines a viable design of a membrane reactor-based PDH plant and shows the potential for miniaturized hollow-fiber membrane reactors to achieve substantial savings. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-09T18:35:50.248779-05:
      DOI: 10.1002/aic.15785
       
  • Predicting Solvent Effects on the 1-dodecene Hydroformylation Reaction
           Equilibrium
    • Authors: Max Lemberg; Martin Gerlach, Emilija Kohls, Christof Hamel, Andreas Seidel-Morgenstern, Matthias Stein, Gabriele Sadowski
      Abstract: This work investigates solvent effects on the reaction equilibrium of the 1-dodecene hydroformylation in a decane/N,N-dimethylformamide solvent system. The reaction was performed at different decane/N,N-dimethylformamide ratios and at temperatures between 368 K and 388 K. The equilibrium concentrations of all reactants and products were determined experimentally. The enthalpy and Gibbs energy of this reaction at the ideal-gas standard state were determined by quantum-chemical calculations in good agreement with literature data. Moreover, quantum-chemically calculated standard Gibbs energies of reaction at infinite dilution in liquid decane/DMF-solvent mixtures allowed a qualitative prediction of the solvent effect on the equilibrium concentrations.Based on the standard Gibbs energy of reaction at the ideal-gas standard state and on fugacity coefficients calculated using the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT), the equilibrium concentrations of reactants and products for the 1-dodecene hydroformylation performed in decane/N,N-dimethylformamide mixtures of different compositions could be predicted in very good agreement with experimental data. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-06T03:38:32.387632-05:
      DOI: 10.1002/aic.15782
       
  • A critical review of statistical calibration/prediction models handling
           data inconsistency and model inadequacy
    • Authors: Pascal Pernot; Fabien Cailliez
      Abstract: Inference of physical parameters from reference data is a well studied problem with many intricacies (inconsistent sets of data due to experimental systematic errors; approximate physical models…). The complexity is further increased when the inferred parameters are used to make predictions – virtual measurements – because parameter uncertainty has to be estimated in addition to parameters best value. The literature is rich in statistical models for the calibration/prediction problem, each having benefits and limitations. We review and evaluate standard and state-of-the-art statistical models in a common bayesian framework, and test them on synthetic and real datasets of temperature-dependent viscosity for the calibration of the Lennard-Jones parameters of a Chapman-Enskog model. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-06T03:34:57.614616-05:
      DOI: 10.1002/aic.15781
       
  • A Multi-Continuum Approach for the Problem of Filtration of Oily-Water
           Systems across Thin Flat Membranes: I. the Framework
    • Authors: Amgad Salama; Mohamed Zoubeik, Amr Henni
      Abstract: In this work, a multi-continuum model is built to estimate the permeate flux of an oily water system across a thin flat membrane in cross filtration methodology. Several continua are constructed to represent droplet and pore size distribution of both the dispersed oil phase and the porous membrane, respectively. The possible permeation of the oil phase has been divided into three criteria. In the first criterion, oil droplets of a given size range may permeate through a given size range of the porous membrane, in the second criterion, oil droplets of another size range may be rejected through another pore size range, and in the third criterion, oil droplets may break apart leaving a tail inside the pore space, which will eventually permeate, and the rest will sweep off due to shear stress. These protocols identify the methodology of the proposed multi-continuum approach, which is introduced in this first part. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-06T03:29:45.069554-05:
      DOI: 10.1002/aic.15784
       
  • Improving Docosahexaenoic Acid Production by Schizochytrium sp. using a
           Newly Designed High-Oxygen-Supply Bioreactor
    • Authors: Dong-Sheng Guo; Xiao-Jun Ji, Lu-Jing Ren, Gan-Lu Li, He Huang
      Abstract: A sufficiently high oxygen supply is crucial for high-cell-density cultivation of aerobic microorganisms, including Schizochytrium sp. We therefore designed a novel bioreactor enabling high-level oxygen supply, and its relevant process parameters and fermentation-stage characteristics were investigated. The real-time changes of pH and non-oil biomass were monitored as proxies for the consumption of nitrogen and lipid accumulation status, which was firstly applied to divided fermentation process with 3 stages. The experimental results showed that the biomass in this porous-membrane-impeller bioreactor was higher than in conventional bioreactor, while docosahexaenoic acid (DHA) percentage in total lipids was lower than in conventional bioreactor. We subsequently implemented a multi-stage control strategy for the porous-membrane-impeller bioreactor, and the maximum biomass, DHA concentration, DHA percentage in biomass and DHA productivity reached 151.0 g/L, 44.3 g/L, 29.33%, 369.08 mg/(L·h), respectively. This study thus provides a highly efficient and economic bioreactor for the production of DHA by Schizochytrium sp. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-06T03:24:35.104955-05:
      DOI: 10.1002/aic.15783
       
  • Function and Effect of the Inner Vortex on the Performance of Cyclone
           Separators
    • Authors: Bo Wang; Binbin Pei, Delong Xu, He Liu, Yunchao Jiang, Yanxin Chen
      Abstract: The inner vortex plays a key role in the performance of cyclone separators. In order to explore the function and effect of the inner vortex in cyclone separators, a series of metal rods and metal blades are inserted in the typical Lapple cyclone separator to reduce the intensity of the inner vortex. Firstly, the changes in general performance of cyclones are measured by experimental methods after insertion of the metal rods and metal blades. The flow field and particle motion are then simulated, respectively, by means of a Reynolds stress model (RSM) and a Lagrangian particle tracking (LPT) model. The results show that when the length of the metal blades is less than the boundary between the inner and outer vortexes, that is, the outer vortex remains unchanged and the inner vortex is destroyed partly, the separation efficiency remains constant and the pressure drop significantly decreases. When the length of the metal blades exceeds the boundary, the inner vortex is completely destroyed, and the outer vortex is significantly damaged, which results in sharp decrease of both the separation efficiency and pressure drop. The results indicate that the inner vortex has a notable effect on the pressure drop and virtually none on the separation efficiency. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-04T17:20:49.849111-05:
      DOI: 10.1002/aic.15780
       
  • Impact of Osmotic Agent on the Transport of Components using forward
           Osmosis to Separate Ethanol from Aqueous Solutions
    • Authors: Alan Ambrosi; Guilherme Lopes Correa, Natiéli Souza de Vargas, Lucas Martim Gabe, Nilo Sérgio Medeiros Cardozo, Isabel Cristina Tessaro
      Abstract: The separation of low molecular weight organic compounds such as the ethanol from aqueous solutions represents an important area to be investigated and increment the range of applications of forward osmosis. This investigation assesses the effects of using different draw solutes for ethanol separation from dilute aqueous solutions. The influence of glucose, sucrose, sodium chloride and magnesium chloride was evaluated in terms of total permeate, reverse solute and ethanol fluxes. Inorganic solutes promoted higher total permeate and ethanol fluxes than the organic solutes (2.5 and 1.5 times higher in average, respectively) for the same molar concentration, while presenting only 1.1 times higher reverse solute fluxes. Despite the lower ethanol flux promoted by the organic draw solutes, these osmotic agents promoted higher concentration of ethanol in the total permeate flux, suggesting that they can also be alternatives for specific processes. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-04T17:20:41.151399-05:
      DOI: 10.1002/aic.15779
       
  • Gas permeation properties for organosilica membranes with different Si/C
           ratios and evaluation of microporous structures
    • Authors: Masakoto Kanezashi; Yuri Yoneda, Hiroki Nagasawa, Kazuki Yamamoto, Joji Ohshita, Toshinori Tsuru
      Abstract: Organosilica membranes were fabricated using bridged organoalkoxysilanes (bis(triethoxysilyl)methane (BTESM), bis(triethoxysilyl)ethane (BTESE), bis(triethoxysilyl)propane (BTESP), bis(trimethoxysilyl)hexane (BTMSH), bis(triethoxysilyl)benzene (BTESB), and bis(triethoxysilyl)octane (BTESO)) to produce highly permeable molecular sieving membranes. The effect of the organoalkoxysilanes on network pore size and microporous structure was evaluated by examining the molecular size and temperature dependence of gas permeance across a wide range of temperatures. Organosilica membranes showed H2/N2 and H2/CH4 permeance ratios that ranged from 10-150, corresponding to network pore size, and both H2 selectivity decreased with an increase in the carbon number between 2 Si atoms. Organosilica membranes showed activated diffusion for He and H2, and a slope of temperature dependence that increased approximate to the increase in the carbon number between 2 Si atoms. The relationship between activation energy and He/H2 permeance ratio for SiO2 and organosilica membranes suggested that the molecular sieving can dominate He and H2 permeation properties via the rigid microporous structure, which was constructed by BTESM and BTESE. With increased in the carbon concentration in silica, polymer chain vibration in organic bridges, which is a kind of solution/diffusion mechanism, can dominate the permeation properties. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-04T17:15:48.909427-05:
      DOI: 10.1002/aic.15778
       
  • CO2 Capture in a Multistage CFB: Part II: Riser with Multiple Cooling
           Stages
    • Authors: Sutthichai Boonprasop; Dimitri Gidaspow, Benjapon Chalermsinsuwan, Pornpote Piumsomboon
      Abstract: A 1 m in diameter and 3.55 m tall fluidized bed riser internally with water tubes, which required 6 equilibrium stage of riser-sorber for capturing about 95 percent of CO2 emitted from a coal power plant, were designed to replace the multi single risers. At the optimum operating condition, the temperature of the cooling tubes in the bottom, the middle and the top of the riser were kept constant values at 50 40 and 30°C, respectively. The hot water (57°C) from lowest exchanger section can be used to pre-heat the spent sorbent for the regeneration in a downer. The rest of the heat for the regenertion is obtained from the stack gas (100 – 130°C). This new concept promises to reduce the energy consumption for CO2 removal from flue gas. The only energy requirement is for pumping fluid and fluidizing particles in the bed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-04T17:00:39.760301-05:
      DOI: 10.1002/aic.15777
       
  • CO2 Capture in a Multistage CFB: Part I: Number of Stages
    • Authors: Sutthichai Boonprasop; Dimitri Gidaspow, Benjapon Chalermsinsuwan, Pornpote Piumsomboon
      Abstract: The most common technology for post-combustion of CO2 capture is the amine solvent scrubber. The energy consumption for capturing CO2 from flue gases using amine solvent technology is 15 to 30% of the power plant electricity production. Hence, there is a need to develop more efficient methods of removing CO2. A circulating fluidized bed using sodium or potassium carbonates is potentially such a process, since their high decomposition pressures allow regeneration at low temperatures using waste heat rather than steam from the power plant. But equilibrium data for the sorbents require the use of several cooled stages to achieve high CO2 conversions. Here a method of computing such a number of stages for a given CO2 conversion was developed using multiphase computational fluid dynamics. It was found that it required 6 equilibrium stages to remove 96 percent of CO2 with the initial mole fraction of 0.15 in a sorption riser. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-04T17:00:32.904769-05:
      DOI: 10.1002/aic.15776
       
  • Issue information
    • Abstract: Cover illustration. Reverse osmosis (RO) water desalination is enabling the development of non-traditional water supplies. Image of a UCLA designed RO plant providing up to 40,000 gallons/day of potable water. Courtesy of Yoram Cohen and Anditya Rahardianto. 10.1002/aic.15726
      PubDate: 2017-05-03T11:35:48.296437-05:
      DOI: 10.1002/aic.15473
       
  • Influence of Adhesion on Random Loose Packings of Binary Micro-Particle
           Mixtures
    • Authors: Wenwei Liu; Sheng Chen, Shuiqing Li
      Abstract: Binary adhesive packings of microspheres with certain size ratios are investigated via a 3D discrete-element method specially developed with adhesive contact mechanics. We found a novel phenomenon that the packing fraction of the binary adhesive mixtures decreases monotonically with the increase of the amount of small components. It was further divulged that this behavior results from the competition between a geometrical filling effect and an adhesion effect. The positive geometrical filling effect only depends on the size ratio, while a dimensionless adhesion parameter Ad is employed to characterize the negative adhesion effect, which comes to its maximum at Ad≈10. Structural properties, including contact network, partial coordination number, radial distribution function and angular distribution function, are analyzed in order to give a better understanding of such adhesive binary packings. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-02T10:59:12.694821-05:
      DOI: 10.1002/aic.15775
       
  • An experimental study of the flow of non-spherical grains in a rotating
           cylinder
    • Authors: Sandip Mandal; D. V. Khakhar
      Abstract: The effect of particle aspect ratio on the rheology of the flow of granular materials is studied experimentally in a quasi-two-dimensional rotating cylinder, using two varieties of prolate spheroidal grains with different aspect ratios. Image analysis of high speed videos is employed to obtain the flow profiles near the centre of the cylinder. The dynamic angle of repose and apparent viscosity in the medium show significant increase with increasing aspect ratio. The mean velocity, root mean square velocity and shear rate profiles are qualitatively similar for non-spherical and spherical particles, however, their magnitudes increase with increasing aspect ratio. A simple scaling is shown to predict the maximum thickness of the flowing layer for all the particles. The predictions of a model for the flow match with the measured mean velocity profiles and layer thickness. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-30T18:40:25.773605-05:
      DOI: 10.1002/aic.15772
       
  • Catalytic ozonation of cinnamaldehyde to benzaldehyde over CaO:
           Experiments and Intrinsic kinetics
    • Authors: Jianfeng Wu; Tongming Su, Yuexiu Jiang, Xinling Xie, Zuzeng Qin, Hongbing Ji
      Abstract: The preparation, characterization of CaO and its application in the catalytic ozonation of cinnamaldehyde to benzaldehyde were studied. The calcination temperature greatly affected the physicochemical properties of CaO, and the CaO calcined at 900°C exhibited the optimal ozone utilization efficiency. When using 0.20 g CaO calcined at 900°C, 750 mL·min−1 oxygen flow rate for generating O3, and reacted at 0°C for 210 min, the cinnamaldehyde conversion reached 97.77%, as well as the benzaldehyde yield was 59.51%. And the cinnamaldehyde conversion in a catalytic ozonation on CaO catalyst maintained above 90% for four used cycles, which exhibited reasonable catalyst stability. The electron donating process of surface O2- on the catalyst is the key to improve the benzaldehyde yield, and based on the intrinsic kinetic study, the Eley-Rideal kinetic model with cinnamaldehyde being adsorbed was the appropriate model for the catalytic ozonation of cinnamaldehyde on CaO. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-30T18:40:17.85115-05:0
      DOI: 10.1002/aic.15773
       
  • Numerical Simulation of Solvent and Water Assisted Electrical Heating of
           Oil Sands Including Aquathermolysis and Thermal Cracking Reactions
    • Authors: Hassan Hassanzadeh; Moosa Rabiei Faradonbeh, Thomas Harding
      Abstract: Simulations of bitumen recovery using solvent- and water-assisted electrical heating of oil sands are presented to evaluate the process and to study gas generation. Aquathermolysis and thermal cracking and dissolution of acid-gases in water are included. Steam-assisted gravity drainage (SAGD) is also simulated for comparison. Results show that gas generation negatively impacts SAGD. However, in electrical heating dissolution of gases into solvent weakens their negative impact. Results indicate that SAGD generates a larger gas volume than electrical heating. In both processes, methane is found to be the major species in the produced gas and H2S concentration can reach high values. While the effect of acid-gas solubility in water on oil recovery is not evident its effect on generated gas volume is significant. Simulation results demonstrate that electrical heating is more energy efficient than SAGD. These results find application in design of experiments and pilot and field-scale implementation of the process. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-30T18:40:15.922771-05:
      DOI: 10.1002/aic.15774
       
  • A Mathematical Model for Optimal Compression Costs in the Hydrogen
           Networks for the Petroleum Refineries
    • Authors: Anoop Jagannath; Ali Almansoori
      Abstract: Hydrogen network design is an important step in hydrogen management of a petroleum refinery that manages the hydrogen distribution and consumption in a cost-effective manner. While most works in this area have primarily focused on minimization of fresh hydrogen requirement and hydrogen purification aspects, very few works have dealt the issue of compression costs in hydrogen network designs. This work proposes a new mathematical model for synthesizing a hydrogen network with minimum compression costs. In contrast to the existing literature, this model uses stream-dependent properties and realistic compressor cost correlations to determine the compression duty and costs respectively. Tests on literature examples show that our model is flexible and gives reasonably favorable solutions than the previous models. Furthermore, the usefulness of understanding the trade-offs between the number of compressors and compression duty and the importance of using stream-dependent conditions in estimating compression costs are also highlighted in this work This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-27T19:07:52.625742-05:
      DOI: 10.1002/aic.15771
       
  • Direct Non-Oxidative Conversion of Methane to Hydrogen and Higher
           Hydrocarbons by Dielectric Barrier Discharge Plasma with Plasma Catalysis
           Promoters
    • Authors: Elijah Chrimba; Kui Zhang, Canan Kazak, Galip Akay
      Abstract: Direct non-oxidative conversion of methane to hydrogen and hydrocarbons were achieved at atmospheric pressure and 120°C using non-thermal plasma sustained by Plasma Catalysis Promoters (PCPs). Reactors had two different electrode configurations. Methane conversion correlated well with the Specific Energy Density (SED). Methane conversion was independent of plasma power, flow rate, electrode configuration or the type of PCPs. Hydrogen selectivity (ca. 60%) was dependent significantly on PCP and electrode configuration. The ethane/ethylene molar ratio increased from 0 to 0.15 with increasing SED. When the SED value was below ca. 100 kJ/L, ethylene was the only C2 hydrocarbon. These results are similar to the recently reported non-oxidative catalytic methane conversion at ca. 1000°C. Therefore, these results represents Process Intensification in methane conversion. PCPs underwent structural and chemical changes but their performance are not affected during an 80-hour experimental period. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-25T10:45:38.573336-05:
      DOI: 10.1002/aic.15769
       
  • Validating Granular Segregation Rate Models
    • Authors: Siying Liu; J.J. McCarthy
      PubDate: 2017-04-25T10:40:28.721918-05:
      DOI: 10.1002/aic.15770
       
  • Facile Synthesis of Pd@Pt Octahedra Supported on Carbon for
           Electrocatalytic Applications
    • Authors: Shengnan Yu; Lei Zhang, Hao Dong, Jinlong Gong
      Abstract: Due to the scarce nature of Pt, it is highly desirable to construct core-shell structures with ultrathin Pt shells while maintaining its high electrocatalytic activity. However, it is necessary to preferentially synthesize a core with a specific structure before further formation of core-shell catalysts with specific morphologies. This prerequisite greatly increases the complexity of the synthesis process. This paper describes a synthetic method of core-shell Pd@Pt octahedra catalysts from Pd nanocubes, truncated nanocubes or truncated octahedra. The formation of octahedral core-shell structures involves two key factors: (1) the oxidative etching process of Pd atoms at the corner sites; (2) the different reduction rates between Pt and Pd precursors. This mechanism can be extended to synthesize carbon-supported sub-8 nm Pd@Pt octahedra from commercial Pd/C catalysts. The derived carbon-supported Pd@Pt octahedra catalysts performed comparable activity and durability for methanol oxidation reaction with state-of-art PtRu/C catalysts. This synthetic method provides an innovative path for large-scale production of well-controlled catalysts. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-21T11:10:20.382368-05:
      DOI: 10.1002/aic.15763
       
  • Selective removal of 1,2-propanediol and 1,2-butanediol from bio-ethylene
           glycol by catalytic reaction
    • Authors: Shuo Ai; Mingyuan Zheng, Yu Jiang, Xiaofeng Yang, Xinsheng Li, Jifeng Pang, Joby Sebastian, Weizhen Li, Aiqin Wang, Xiaodong Wang, Tao Zhang
      Abstract: Ethylene glycol (EG), synthesized from biomass, frequently contains refractory 1,2-propanediol (PDO) and 1,2-butanediol (BDO). Selective removal of PDO and BDO was realized herein by catalytic dehydration to form volatile aldehydes, ketones, and acetals. Various acidic and basic catalysts were screened under a range of conditions for the conversion of a mixture containing 73 wt% EG, 20 wt% PDO and 7 wt% BDO. Over H-Beta 26 zeolite, the most selective catalyst among tested, PDO and BDO conversions reached 99.1% and 99.3%, respectively after 4 h reaction at 453 K, with separation factors over 2. The activation energies for EG, PDO, and BDO dehydration were ca. 99.3, 69.9, and 54.0 kJ/mol, respectively, accounting for the high reactivity of PDO and BDO. The dehydration largely proceeded in the micropores of H-Beta and depended on the number of strong Brønsted acid sites, but excessively strong acid sites enhanced the polymerization of EG. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-21T11:10:18.434181-05:
      DOI: 10.1002/aic.15764
       
  • Numerical prediction of a Nusselt number equation for stirred tanks with
           helical coils
    • Authors: R. P. Jaimes; J. R. Nunhez
      Abstract: A methodology to obtain a Nusselt correlation for stirred tank reactors is presented. The novelty of the approach is the use of a validated computational model to obtain the heat transfer coefficients. The advantages of this new approach are many, including the possibility of testing different heat transfer configurations to obtain their Nusselt correlation without performing experimental runs. Physical phenomena involved was represented both qualitatively and quantitatively. The classical experimental work of Oldshue and Gretton (1954) illustrates the procedure. A sufficient number of virtual points in the whole range of the Reynolds number should be obtained. Results strongly depend on mesh refinement in the boundary layer, so a procedure is suggested to guarantee heat transfer coefficients are accurately estimated. The final Nusselt correlation was compared against all the 107 experimental points of the work by Oldshue and Gretton [1], and an average deviation on the results of 10.7%. This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-21T11:07:44.021629-05:
      DOI: 10.1002/aic.15765
       
  • FeOx Supported Single-Atom Pd Bifunctional Catalyst for Water Gas Shift
           Reaction
    • 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
           Networks
    • 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
           Spectroscopy
    • 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
       
  • 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
           Column
    • 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
           materials*
    • 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
           process
    • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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: 1769 - 1770
      PubDate: 2017-05-03T11:35:45.392515-05:
      DOI: 10.1002/aic.15472
       
  • Unraveling the droplet drying characteristics of crystallization-prone
           mannitol – experiments and modeling
    • Authors: Chen Loon Har; Nan Fu, Eng Seng Chan, Beng Ti Tey, Xiao Dong Chen
      Pages: 1839 - 1852
      Abstract: Spray-dried mannitol is a potential lactose replacement in pharmaceutical formulations, yet the drying behavior of individual mannitol droplets within the spray chamber has not been fully understood. This work explored the drying characteristics of mannitol by employing the reaction engineering approach (REA) in data analysis. A glass filament single droplet drying technique was used to monitor the changes in droplet temperature, mass, and diameter. The drying kinetics data obtained clearly demonstrated the droplet “wet-bulb” period, the crust formation, and the crystallization phenomena. The master activation-energy curves developed from REA modeling responded sensitively to varying drying temperatures, which could have led to different crystallization events. The deviation of these plots from the expected norms that do not encounter a phase change was used effectively to discern the physics involved. A REA kinetic model was proposed to assist in process optimization of large-scale spray-drying operations. © 2017 American Institute of Chemical Engineers AIChE J, 63: 1839–1852, 2017
      PubDate: 2017-01-11T10:05:33.672604-05:
      DOI: 10.1002/aic.15624
       
  • Multi-objective optimization superimposed model-based process design of an
           enzymatic hydrolysis process
    • Authors: Philip Zitzewitz; Georg Fieg
      Pages: 1974 - 1988
      Abstract: The concepts of green process engineering and rigorous model-based approaches have proven to be highly beneficial in process engineering. Although a combination of these two principles thus appears extremely promising, it is not found very commonly in literature. The very high complexity resulting from this combination poses great challenges for the process design and design engineers. Therefore, this work presents an innovative methodology for the model-based process design with superimposed multi-objective optimization for an exemplary process. This process for the enzymatic hydrolysis of fatty acid methyl ester combines several aspects of green process engineering and represents an exemplary process with an enzymatic liquid-liquid-solid reaction system. The optimization results based on operating and investment costs reveal important insights on the exemplary process and highlight the great advantages of the developed methodology as a profound basis for academic and industrial process design purposes. © 2017 American Institute of Chemical Engineers AIChE J, 63: 1974–1988, 2017
      PubDate: 2017-01-05T15:50:26.807322-05:
      DOI: 10.1002/aic.15609
       
  • Synthesis and optimization of membrane cascade for gas separation via
           mixed-integer nonlinear programming
    • Authors: Alicia Aliaga-Vicente; José A. Caballero, María J. Fernández-Torres
      Pages: 1989 - 2006
      Abstract: Currently, membrane gas separation systems enjoy widespread acceptance in industry as multistage systems are needed to achieve high recovery and high product purity simultaneously, many such configurations are possible. These designs rely on the process engineer's experience and therefore suboptimal configurations are often the result. This article proposes a systematic methodology for obtaining the optimal multistage membrane flow sheet and corresponding operating conditions. The new approach is applied to cross-flow membrane modules that separate CO2 from CH4, for which the optimization of the proposed superstructure has been achieved via a mixed-integer nonlinear programming model, with the gas processing cost as objective function. The novelty of this work resides in the large number of possible interconnections between each membrane module, the energy recovery from the high pressure outlet stream and allowing for nonisothermal conditions. The results presented in this work comprise the optimal flow sheet and operating conditions of two case studies. © 2017 American Institute of Chemical Engineers AIChE J, 63: 1989–2006, 2017
      PubDate: 2017-01-17T08:10:41.497945-05:
      DOI: 10.1002/aic.15631
       
  • Mathematical modeling of molecular weight distribution in miniemulsion
           polymerization with oil-soluble initiator
    • Authors: Claudia A. Capeletto; Cristiane Costa, Claudia Sayer, Pedro H. H. Araújo
      Pages: 2128 - 2140
      Abstract: A mathematical model for the study of reaction kinetics and molecular weight distributions in miniemulsion polymerization systems with oil-soluble initiators is presented. The mathematical model allows the computation of the evolution of the complete molecular weight distribution with chain lengths of up to 105 mers in miniemulsion polymerization by direct integration in reasonable computational time. Also, no restriction in the kinetic regime is needed, as the model is able to represent both compartmentalized and pseud-bulk systems. The model was validated with experimental results for methyl methacrylate and styrene homopolymerizations, with two different oil-soluble initiators, and adequately represented both the kinetics and molecular weight distributions of these systems. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2128–2140, 2017
      PubDate: 2017-01-04T20:20:43.21831-05:0
      DOI: 10.1002/aic.15608
       
  • Novel hierarchical Ni/MgO catalyst for highly efficient CO methanation in
           a fluidized bed reactor
    • Authors: Jun Li; Qingshan Zhu, Wencai Peng, Qiang Zhang, Guohua Luo, Fei Wei
      Pages: 2141 - 2152
      Abstract: A facile synthesis of the hierarchical Ni/MgO catalyst is reported, with extremely fine dispersion of Ni nanoparticles (NPs) and high surface oxygen mobility. The hierarchical Ni/MgO catalyst exhibits higher activity for CH4 formation than that prepared by the impregnation method. The enhanced activity and thermal stability of the hierarchical Ni/MgO catalyst is attributed to hierarchical MgO particles with a multilayer structure and high surface oxygen mobility. This induces better metal-support interactions, high Ni dispersion to prevent Ni NPs sintering, and the high surface oxygen mobility provides a high resistance to carbon deposition. Compared to the impregnated Ni/MgO catalyst, the hierarchical Ni/MgO catalyst exhibits a better fluidization quality and a higher attrition-resistance in a fluidized-bed reactor. This approach to improve the catalytic activity by creation of hierarchical Ni/MgO particles is encouraging for the design of novel catalysts for synthetic natural gas production, especially from the perspective of matching catalysts with fluidized-bed reactors. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2141–2152, 2017
      PubDate: 2017-01-06T14:30:26.743373-05:
      DOI: 10.1002/aic.15597
       
  • Behaviors and kinetic models analysis of Li4SiO4 under various CO2 partial
           pressures
    • Authors: Qi Zhang; Dong Peng, Sai Zhang, Qian Ye, Yongqiang Wu, Yanhui Ni
      Pages: 2153 - 2164
      Abstract: The absorption behaviors of Li4SiO4 sorbent under various CO2 partial pressures and temperatures were investigated through numerical and experimental methods. It was found that Li4SiO4 showed poor absorption capacity at high temperatures (>525°C) under CO2 partial pressure of 5066 Pa. This phenomenon was explained by the thermodynamic results from FactSage5.5 software. Meanwhile, a modified Jander-Zhang model based on the double-shell structure of the Li4SiO4 sorbent was developed to describe the absorption kinetic behaviors of CO2 on Li4SiO4. The results showed that the modified Jander-Zhang model could fit the kinetic experimental data well. Furthermore, the influence of steam on CO2 absorption was also analyzed by the modified Jander-Zhang model. The results showed that the activation energy in the absorption process with steam was smaller than that without steam, which indicated that the presence of steam could promote the CO2 diffusion in product layer, therefore, improving the sorption capacity. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2153–2164, 2017
      PubDate: 2017-01-13T11:30:27.647216-05:
      DOI: 10.1002/aic.15627
       
  • Depositing lignin on membrane surfaces for simultaneously upgraded reverse
           osmosis performances: An upscalable route
    • Authors: Feng Zhang; Yaping Wu, Weixing Li, Weihong Xing, Yong Wang
      Pages: 2221 - 2231
      Abstract: Reverse osmosis (RO) have been widely used to produce clean water and there is a strong need to enhance their permeability at no sacrifice of their other performances, e.g., selectivity. We deposit low-cost biopolymer, lignin, onto the surface of RO membranes by a simple filtration method. Lignin is deposited to the membrane surface via both hydrogen bonding and π-π interaction. Lignin deposition reduces the surface roughness of the membrane and enhances its negatively charging, while the surface hydrophilicity is maintained. Surprisingly, water permeation, salt rejection, and fouling resistance of the lignin-deposited membranes are simultaneously improved. More importantly, we demonstrate that this deposition method can be easily extended to modify commercial RO membrane modules, indicating the excellent upscalability of this method. We use the lignin-deposited membranes to treat real effluents of dyeing and papermaking and they perform much better than the virgin, unmodified membranes. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2221–2231, 2017
      PubDate: 2017-01-12T13:45:28.743323-05:
      DOI: 10.1002/aic.15628
       
  • Direct silanization of polyurethane foams for efficient selective
           absorption of oil from water
    • Authors: Sen Xiong; Zhaoxiang Zhong, Yong Wang
      Pages: 2232 - 2240
      Abstract: Absorption is an effective method to collect oil spills and solvent leakages from water. However, the currently used oil absorbents are still suffering from high cost, tedious preparation, and low recyclability. In this work, we report an extremely simple and low-cost strategy to produce oil absorbents by directly coupling alkoxysilane onto the surface of polyurethane (PU) foams. Such direct silanization renders the initially amphiphilic foams a strong hydrophobicity and consequently a water-repelling and oil-absorptive functionality. The silanized foams exhibit highest absorption capacities as well as best recyclability among all PU-based oil absorbents. More practically, the silanized PU foams can be used to recover crude oil spills with an absorption capacity of higher than 75 times of their own weight, and maintain 90% of the initial absorption capacity after eight times reusage. Interestingly, we invent portable oil suckers for continuous oil absorption from water by filling vacuum cleaners with the silanized foams. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2232–2240, 2017
      PubDate: 2017-01-15T19:05:31.516742-05:
      DOI: 10.1002/aic.15629
       
  • Non-ionic soft materials influence on filtration resistance and cake dry
           matter content
    • Authors: Mogens Hinge; Morten Lykkegaard Christensen
      Pages: 2241 - 2247
      Abstract: Filtration of organic slurries is important in many industries but challenging because the hydraulic resistance is high due to gel materials in the slurries. Particles with solid polystyrene (PS) core and varying amount of poly(N-isopropylacrylamide) (PNIPAM) gel surface were synthesized. At low amount of gel, the gel deformed and partly filled the cake void increasing the resistance. This was successfully fitted using a semi-theoretical model for deformable particles. At high amount of gel, the gel deformed filling the entire cake void and the resistance was dominated by the gel. During consolidation, the primary retardation time increased three orders of magnitude with gel thickness as expected as primary consolidation were dominated by the dissipation of pore water. The secondary retardation time also increased but not as pronounced as primary retardation time. Secondary consolidation was due to local compression of the gel and therefore less dependent on gel thickness. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2241–2247, 2017
      PubDate: 2017-01-15T19:00:28.835718-05:
      DOI: 10.1002/aic.15632
       
  • Automatic detection of contact lines in slot coating flows
    • Authors: Hyeyoung Hong; Jaewook Nam
      Pages: 2440 - 2450
      Abstract: Slot coating is a versatile method used to manufacture thin films at high speed. The success of the method lies in controlling a coating flow surrounded by upstream and downstream menisci. The meniscus edges that are in contact with either the die lips or the substrate surfaces are called contact lines. Visualizations of such lines are important in coating flow research because their shapes and locations are sensitive to operating conditions. In this study, we propose a robust image analysis algorithm for images acquired from flow visualizations. The images are dissected into three regions with different characteristics that need to be treated using different pre-processing techniques. A standard optimal edge detector is then sufficient to capture the contact lines, and post-processing steps can be simplified. We also highlight two applications of the proposed algorithm: coating windows, and transient behaviors under external disturbances. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2440–2450, 2017
      PubDate: 2017-01-04T09:10:34.208794-05:
      DOI: 10.1002/aic.15612
       
  • Analysis of flow and mixing in screw elements of corotating twin-screw
           extruders via SPH
    • Authors: Andreas Eitzlmayr; Josip Matić, Johannes Khinast
      Pages: 2451 - 2463
      Abstract: Due to its meshless nature, the smoothed particle hydrodynamics method (SPH) provides high potential for the simulation of free-surface flows and mixing in complex geometries. We used SPH to analyze the flow inside five typical screw elements of corotating twin-screw extruders, two conveying elements, two kneading elements and a mixing element. Our results show conveying capabilities, pressure generation and power input for various operation states, completely and partially filled. We conducted a detailed mixing analysis based on tracer particles, which yielded the time evolution of the intensity of segregation for different tracers. From that, we determined exponential mixing rates, which describe the relative decrease of the intensity of segregation per screw revolution and characterize the mixing performance in different operation states. This provides valuable input information for simplified models of extruders, which are relevant to industrial applications and can significantly contribute to the efficient design, optimization and scale-up of extruders. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2451–2463, 2017
      PubDate: 2017-01-06T14:25:26.710948-05:
      DOI: 10.1002/aic.15607
       
  • Molecular mechanism for liquid–liquid extraction: Two-film theory
           revisited
    • Authors: Yangxu Hu; Zhiping Liu, Xigang Yuan, Xianren Zhang
      Pages: 2464 - 2470
      Abstract: We investigate here the molecular mechanism for liquid-liquid extraction and revisit the classical two-film theory. With equilibrium and non-equilibrium molecular dynamics simulations, we illustrate the kinetics of solute crossing the interface and in particular the structure of the interface at which two stagnant liquid films adhere. Our simulation results show that beyond the two-film theory, the interface is well structured and plays an essential role in solute transfer. We found that at the well-developed interface region the overall density profile exhibits a dip, while the solute concentration shows a significant maximum. Free energy analysis demonstrates the interfacial enrichment of solute molecules serving as a potential well for solute adsorption. Thus, different from the assumption of the two-film theory, our simulations show that there exists a resistance for solute molecules crossing the interface, which could be overcome only at high interface concentration of solute caused by interfacial enrichment. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2464–2470, 2017
      PubDate: 2017-01-17T08:40:30.903541-05:
      DOI: 10.1002/aic.15636
       
  • Stability of gravitationally unstable double diffusive transient boundary
           layers with variable viscosity in porous media
    • Authors: Nasser Sabet; Hassan Hassanzadeh, Jalal Abedi
      Pages: 2471 - 2482
      Abstract: We study the double diffusive convection (DDC) in porous media through linear stability analysis (LSA) and direct numerical simulations (DNS). Unlike the previous studies that assume static solutal or thermal fields, the developed model is able to capture the transient behavior of both fields. We show that under the assumption of static field, the role of Lewis number cannot be distinguished. Under transient fields, we conclude that higher Lewis numbers result in earlier instability of the boundary layers. Moreover, the effect of viscosity contrast is explained in terms of the mobility of the boundary layer. The DNS results confirm the validity of LSA predictions. We also obtain the critical Rayleigh number and show that in the presence of viscosity contrast, it can be much smaller than the conventional limit of 4π2. This study provides a better understanding of the transient nature of DDC in the presence of viscosity variations. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2471–2482, 2017
      PubDate: 2017-01-13T11:25:40.512316-05:
      DOI: 10.1002/aic.15626
       
  • An optimization-based approach for structural design of self-assembled DNA
           tiles
    • Authors: Yu Gao; Yongli Mi, Richard Lakerveld
      Pages: 1804 - 1817
      Abstract: DNA tiles are self-assembled nanostructures, which offer exciting opportunities for synthesis of novel materials. A challenge for structural design of DNA tiles is to identify optimal locations for so-called crossovers, which are bridges between DNA double helices formed by pairs of single-stranded DNA. An optimization-based approach is presented to identify optimal locations for such crossovers. Minimization of a potential-energy model for a given structural design demonstrates the importance of local minima. Both deterministic global optimization of a reduced model and multistart optimization of the full model are applied successfully to identify the global minimum. MINLP optimization using a branch-and-bound algorithm (GAMS/SBB) identifies an optimal structural design of a DNA tile successfully with significant reduction in computational load compared to exhaustive enumeration, which demonstrates the potential of the proposed method to reduce trial-and-error efforts for structural design of DNA tiles. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1804–1817, 2017
      PubDate: 2016-11-03T18:09:32.913983-05:
      DOI: 10.1002/aic.15546
       
  • Dynamic properties of a continuous stirred tank biofilm bioreactor for
           aerobic processes
    • Authors: Szymon Skoneczny; Bolesław Tabiś
      Pages: 1818 - 1829
      Abstract: A dynamic analysis of a continuous stirred tank bioreactor with biofilm was performed. The existence of gas, liquid, and biofilm were taken into account. The proposed heterogeneous model of such bioreactor takes into account dynamic biofilm growth and interphase transfer of substrates and biomass for a double-substrate aerobic process. Simulations were performed to investigate the influence of important process parameters, i.e., toxic substrate concentration in the feed stream, detachment rate coefficient, mean residence time of the liquid and aeration intensity, on dynamic properties of the bioreactor. Dynamic behavior at conditions of anoxia of microorganisms were shown. A method was proposed to reduce bioreactor start-up time significantly. The paper presents a mathematical model of the bioreactor that uses a discrete model of biofilm growth based on the theory of cellular automata. Dynamics of the bioreactor based on the continuous and discrete biofilm model was compared. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1818–1829, 2017
      PubDate: 2016-11-29T12:01:25.550738-05:
      DOI: 10.1002/aic.15591
       
  • Synthetic Saccharomyces cerevisiae-Shewanella oneidensis consortium
           enables glucose-fed high-performance microbial fuel cell
    • Authors: Tong Lin; Xue Bai, Yidan Hu, Bingzhi Li, Ying-Jin Yuan, Hao Song, Yun Yang, Jingyu Wang
      Pages: 1830 - 1838
      Abstract: Microbial fuel cells (MFCs) were green and sustainable bio-electrochemical reactors for simultaneous wastewater treatment and electricity harvest from organic wastes. However, exoelectrogens, such as Shewanella and Geobacter being widely studied in MFCs, could only use a limited spectrum of carbon sources. To expand the carbon source range being used in MFCs, we herein rationally designed a glucose-fed fungus-bacteria microbial consortium including a fermenter (Saccharomyces cerevisiae) in which the ethanol pathway was knocked out and the lactic acid biosynthesis pathway from Bovin was introduced into S. cerevisiae, and an exoelectrogen (Shewanella oneidensis MR-1). We optimized the co-culturing conditions of the microbial consortium to achieve an optimal coordination between carbon source metabolism of the fermenter and extracellular electron transfer of the exoelectrogen, such that lactate, the metabolic product of glucose by the recombinant S. cerevisiae, was continuously supplied to S. oneidensis in a constant level until glucose exhaustion. This metabolic coordination between the fermenter and the exoelectrogen enabled bioelectricity production in a glucose-fed MFC. Furthermore, a porin protein encoded by oprF gene from Pseudomonas aeruginosa was incorporated into the outer membrane of S. oneidensis to enhance membrane permeability and its hydrophobicity, which in turn facilitated its biofilm formation and power generation. The glucose-fed MFC inoculated with the recombinant S. cerevisiae-recombinant S. oneidensis generated a maximum power density of 123.4 mW/m2, significantly higher than that of recombinant S. cerevisiae-wild-type S. oneidensis (71.5 mW/m2). Our design strategy of synthetic microbial consortia was highly scalable to empower the possibility of a wide range of carbon sources being used in MFCs, e.g., xylose, cellulosic biomass, and recalcitrant wastes. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1830–1838, 2017
      PubDate: 2016-12-23T11:45:25.726289-05:
      DOI: 10.1002/aic.15611
       
  • Partial slip boundary conditions for collisional granular flows at flat
           frictional walls
    • Authors: Lei Yang; J. T. Padding, J. A. M. Kuipers
      Pages: 1853 - 1871
      Abstract: We derive new boundary conditions (BCs) for collisional granular flows of spheres at flat frictional walls. A new theory is proposed for the solids stress tensor, translational and rotational energy dissipation rate per unit area and fluxes of translational and rotational fluctuation energy. In the theory we distinguish between sliding and sticking collisions and include particle rotation. The predictions are compared with literature results obtained from a discrete particle model evaluated at a given ratio of rotational to translational granular temperature. We find that the new theory is in better agreement with the observed stress ratios and heat fluxes than previous kinetic theory predictions. Finally, we carry out two fluid model simulations of a bubbling fluidized bed with the new BCs, and compare the simulation results with those obtained from discrete particle simulations. The comparison reveals that the new BCs are better capable of predicting solids axial velocity profiles, solids distribution near the walls and granular temperatures. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1853–1871, 2017
      PubDate: 2016-11-05T10:42:37.892858-05:
      DOI: 10.1002/aic.15534
       
  • Triboelectric charging of monodisperse particles in fluidized beds
    • Authors: Jari Kolehmainen; Ali Ozel, Christopher M. Boyce, Sankaran Sundaresan
      Pages: 1872 - 1891
      Abstract: To investigate the interplay between particle charging and hydrodynamics in fluidized beds, models for triboelectric charging and electrostatic forces were built into a computational fluid dynamics-discrete element method model. Charge transfer was governed by the difference in effective work function between contacting materials as well as the electric field at the point of contact. Monodisperse particles were fluidized with an effective work function difference between the particles and the conducting walls. For smaller work function differences, hydrodynamics were not changed significantly as compared with an uncharged case. In these simulations, the average charge saturated at a value much lower than the value anticipated based on the work function difference, and a unimodal distribution of charges was observed. For larger work function differences, particles stuck to walls and bed height oscillations due to slugging were less pronounced. For these cases, a bimodal distribution of charges emerged due to effects from strong electric fields. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1872–1891, 2017
      PubDate: 2016-11-18T14:10:57.011992-05:
      DOI: 10.1002/aic.15541
       
  • An economic model predictive control approach to integrated production
           management and process operation
    • Authors: Anas Alanqar; Helen Durand, Fahad Albalawi, Panagiotis D. Christofides
      Pages: 1892 - 1906
      Abstract: Managing production schedules and tracking time-varying demand of certain products while optimizing process economics are subjects of central importance in industrial applications. We investigate the use of economic model predictive control (EMPC) in tracking a production schedule. Specifically, given that only a small subset of the total process state vector is typically required to track certain scheduled values, we design a novel EMPC scheme, through proper construction of the objective function and constraints, that forces specific process states to meet the production schedule and varies the rest of the process states in a way that optimizes process economic performance. Conditions under which feasibility and closed-loop stability of a nonlinear process under such an EMPC for schedule management can be guaranteed are developed. The proposed EMPC scheme is demonstrated through a chemical process example in which the product concentration is requested to follow a certain production schedule. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1892–1906, 2017
      PubDate: 2016-11-02T13:03:46.617609-05:
      DOI: 10.1002/aic.15553
       
  • Shell and tube heat exchanger design using mixed-integer linear
           programming
    • Authors: Caroline de O. Gonçalves; André L. H. Costa, Miguel J. Bagajewicz
      Pages: 1907 - 1922
      Abstract: The design of heat exchangers, especially shell and tube heat exchangers was originally proposed as a trial and error procedure where guesses of the heat transfer coefficient were made and then verified after the design was finished. This traditional approach is highly dependent of the experience of a skilled engineer and it usually results in oversizing. Later, optimization techniques were proposed for the automatic generation of the best design alternative. Among these methods, there are heuristic and stochastic approaches as well as mathematical programming. In all cases, the models are mixed integer non-linear and non-convex. In the case of mathematical programming solution procedures, all the solution approaches were likely to be trapped in a local optimum solution, unless global optimization is used. In addition, it is very well-known that local solvers need good initial values or sometimes they do not even find a feasible solution. In this article, we propose to use a robust mixed integer global optimization procedure to obtain the optimal design. Our model is linear thanks to the use of standardized and discrete geometric values of the heat exchanger main mechanical components and a reformulation of integer nonlinear expressions without losing any rigor. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1907–1922, 2017
      PubDate: 2016-11-15T11:07:41.66184-05:0
      DOI: 10.1002/aic.15556
       
  • Continuous-time scheduling formulation for straight pipelines
    • Authors: Hossein Mostafaei; Pedro M. Castro
      Pages: 1923 - 1936
      Abstract: Pipelines represent the most cost-effective way of transporting large quantities of refined petroleum products over large distances but can be challenging to operate. In this article, we propose a new mixed-integer linear programming formulation for scheduling straight pipelines with multiple single and dual purpose nodes. The model allows for simultaneous injections and deliveries, and interacting pumping runs, in which a segment of the pipeline simultaneously receives material from its refinery and upstream segment. In contrast to previous batch centric models, it uses segment dependent coordinates. To make it efficient by design, we rely on generalized disjunctive programming and develop disjunctions for which the convex hull reformulation is simple (roughly the same number of variables and constraints as its big-M counterpart). Through the solution of a set of test cases from the literature, we show a better utilization of the pipeline capacity that is translated into a lower makespan. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1923–1936, 2017
      PubDate: 2016-11-21T15:45:45.12095-05:0
      DOI: 10.1002/aic.15563
       
  • An adaptive parallel tempering method for the dynamic data-driven
           parameter estimation of nonlinear models
    • Authors: Matthew J. Armstrong; Antony N. Beris, Norman J. Wagner
      Pages: 1937 - 1958
      Abstract: An adaptive parallel tempering algorithm is developed in a user-friendly fashion that efficiently and robustly generates near-optimum solutions. Using adaptive, implicit, time-integration methods, the method allows fitting model parameters to dynamic data. The proposed approach is relatively insensitive to the initial guess and requires minimal fine-tuning: most of the algorithm parameters can be determined adaptively based on the analysis of few model simulations, while default values are proposed for the few remaining ones, the exact values of which do not sensitively affect the solution. The method is extensively validated through its application to a number of algebraic and dynamic global optimization problems from Chemical Engineering literature. We then apply it to a multi-parameter, highly nonlinear, model of the rheology of a thixotropic system where we show how the present approach can be used to robustly determine model parameters by fitting to dynamic, large amplitude, oscillatory stress vs. shear rate, data. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1937–1958, 2017
      PubDate: 2016-11-25T21:30:39.718694-05:
      DOI: 10.1002/aic.15577
       
  • Dynamic models and fault diagnosis-based triggers for closed-loop
           scheduling
    • Authors: Cara R. Touretzky; Iiro Harjunkoski, Michael Baldea
      Pages: 1959 - 1973
      Abstract: Establishing an explicit feedback connection between production management and process control decisions is a key requirement for more nimble and cost effective process operations in today's variable market conditions. Past research efforts focused on embedding dynamic process information in the production scheduling problem. In this article, we propose a novel framework for closing the scheduling loop, based on considering the process-level events and disturbances that impact the implementation of scheduling decisions. We emphasize the role of a comprehensive fault detection, isolation and reconstruction mechanism as a trigger for rescheduling decisions and for reflecting the process capabilities altered by these events in the rescheduling problem formulation. Our framework is agnostic to the process type, and we present two (continuous process, sequential batch process) case studies to demonstrate its applicability. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1959–1973, 2017
      PubDate: 2016-12-01T16:01:42.26816-05:0
      DOI: 10.1002/aic.15564
       
  • Experimental study on CH* chemiluminescence characteristics of impinging
           flames in an opposed multi-burner gasifier
    • Authors: Qing Zhang; Yan Gong, Qinghua Guo, Xudong Song, Guangsuo Yu
      Pages: 2007 - 2018
      Abstract: The bandpass filtered images of impinging flames in an opposed multi-burner (OMB) gasifier was visualized by a CCD camera combined with a high temperature endoscope. A filtering and image processing method by use of three bandpass filters was applied to subtract soot and CO2* contributions in the CH* band and obtain the CH* chemiluminescence of impinging flames. The results show that a clear reaction core is generated in the impinging zone of four-burner impinging flames. The size of the reaction core is affected by the O/C equivalence ratio ([O/C]e) and the impingement effect is relatively stronger at lower [O/C]e. The flame lift-off length in the gasifier is jointly controlled by the syngas concentration and the diesel atomization effect. The impingement effect shortens the flame lift-off length. The relationship between the syngas concentration and the maximum CH* intensity makes it possible to evaluate the syngas concentration from CH* intensity. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2007–2018, 2017
      PubDate: 2016-11-03T18:09:48.45904-05:0
      DOI: 10.1002/aic.15555
       
  • Kinetic study of methane reforming with carbon dioxide over NiCeMgAl
           bimodal pore catalyst
    • Authors: Zhenghong Bao; Yongwu Lu, Fei Yu
      Pages: 2019 - 2029
      Abstract: The kinetic behavior of NiCeMgAl bimodal pore catalyst for methane reforming with CO2 was investigated after the elimination of external and internal diffusion effects in a fixed-bed reactor as a function of temperature and partial pressures of reactants and products. Increase in CO2 partial pressure favors the consumptions of CH4 and CO2 but inhibits the formation of H2 due to the existence of reverse water gas shift (RWGS) reaction. The reforming rate increased first and then reached a horizontal stage with the rise of CH4 partial pressure. A Langmuir–Hinshelwood model was developed assuming that the carbon deposition is ignorable but the RWGS reaction is non-ignorable and the removal of adsorbed carbon intermediate is the rate-determining step. A nonlinear least-square method was applied to solve the kinetic parameters. The derived kinetic expression fits the experimental data very well with a R2 above 0.97, and also predicts the products flow rate satisfactorily. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2019–2029, 2017
      PubDate: 2016-11-24T11:15:31.305502-05:
      DOI: 10.1002/aic.15579
       
  • What is the leanest stream to sustain a nonadiabatic loop reactor:
           Analysis and methane combustion experiments
    • Authors: Aharon Y. Madai; Olga Nekhamkina, Moshe Sheintuch
      Pages: 2030 - 2042
      Abstract: While previous studies experimentally demonstrated that loop reactor (LR) can be sustained with a lean feed (using ethylene combustion) and have analyzed the single-reaction adiabatic case, this work analyzes the effects of heat loss and of reactor size to determine the leanest stream (expressed in terms of adiabatic temperature rise ΔTlim) that will sustain the operation. For an adiabatic infinitely long reactor ΔTlim0 while for a finite reactor ΔTlim scales as (1 + Pe/4)−1 where Pe = Luρcpf/k, and heat loss increases this limit by (β/Pe)1/2. Thus, a good design of a LR will aim to decrease conductivity (k) and radial heat-transfer coefficient (β) while increasing throughput (u) and reactor length. This article is also the first experimental demonstration of auto-thermal operation in a LR for catalytic abatement of low-concentration of methane, showing the leanest stream to be of 8000 ppm vs. 33,000 ppm in a once-through reactor. Experimental combustion results of methane and of ethylene are compared with model predictions. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2030–2042, 2017
      PubDate: 2016-11-26T16:55:30.780502-05:
      DOI: 10.1002/aic.15580
       
  • A complete understanding of the reaction kinetics for the industrial
           production process of expandable polystyrene
    • Authors: Lies De Keer; Paul H. M. Van Steenberge, Marie-Françoise Reyniers, Guy B. Marin, Klaus-Dieter Hungenberg, Libor Seda, Dagmar R. D'hooge
      Pages: 2043 - 2059
      Abstract: For the industrial expandable polystyrene (EPS) process, the Predici software package is successfully applied to demonstrate that the composite kt model is the most appropriate one to accurately account for diffusional limitations on termination. For a broad range of conditions, the reported set of model parameters allows an excellent description of experimental data on monomer conversion and molar mass distribution (MMD). For low temperatures and dicumylperoxide amounts (
      PubDate: 2016-11-26T17:00:31.115232-05:
      DOI: 10.1002/aic.15587
       
  • Simulation of dry reforming of methane in a conventional downfired
           reformer
    • Authors: Yutian R. Zhao; Dean A. Latham, Brant A. Peppley, Kim B. McAuley, Hui Wang, Rick LeHoux
      Pages: 2060 - 2071
      Abstract: A model for industrial top-fired dry reforming of methane (DRM) and for combined dry reforming and steam reforming of methane was developed for the first time. The model calculates and gives predictions on the temperature profiles for fuel gas, tube walls, and process gas, as well as the process gas composition profiles over the length of the tubes. Radiative heat transfer is modeled by Hottel Zone method. Material and energy balances are solved numerically using Newton-Raphson solver. Kinetic models for two different DRM catalysts are applied in the model for comparison. Simulation results show that water–gas shift reaction is important in DRM and addition of steam in the feed of process gas is beneficial for industrial production. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2060–2071, 2017
      PubDate: 2016-11-28T19:11:20.867418-05:
      DOI: 10.1002/aic.15582
       
  • Ethylene glycol production from glucose over W-Ru catalysts: Maximizing
           yield by kinetic modeling and simulation
    • Authors: Guanhong Zhao; Mingyuan Zheng, Ruiyan Sun, Zhijun Tai, Jifeng Pang, Aiqin Wang, Xiaodong Wang, Tao Zhang
      Pages: 2072 - 2080
      Abstract: The kinetics of glucose conversion to ethylene glycol (EG) in the presence of ammonium paratungstate and Ru/AC catalysts was studied to model and predict the reaction performance under a range of conditions. A mathematical model was established through the rational simplification of the reaction network on the basis of a continuous stirred-tank model. The kinetic data of six major reactions in the network were experimentally measured, and the analytical expressions of overall reaction kinetics were obtained by introducing the kinetic data to the model. Yields of EG, hexitols and gas were described as functions of the reaction temperature, the concentration of glucose in the feedstock and the feeding rate. The simulation results matched the experimental data of glucose conversion, demonstrating the validity of the model and method for studying the overall kinetics of glucose conversion to EG over W-Ru catalysts. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2072–2080, 2017
      PubDate: 2016-11-29T18:05:40.101727-05:
      DOI: 10.1002/aic.15589
       
  • Enhanced performance of Rh1/TiO2 catalyst without methanation in water-gas
           shift reaction
    • Authors: Hongling Guan; Jian Lin, Botao Qiao, Shu Miao, Ai-Qin Wang, Xiaodong Wang, Tao Zhang
      Pages: 2081 - 2088
      Abstract: Water-gas shift (WGS) reaction is an important process for industrial hydrogen production. The side reaction of methanation often causes unavoidable loss of H2 along with this reaction. Here, we report a Rh1/TiO2 single-atom catalyst (SAC) with appreciable loading of 0.37 wt %, which exhibited an overall CO conversion of ∼95% but without any methanation at 300°C, even under CO2- and H2-rich WGS stream. The specific activity of this SAC was around four times higher than that of cluster catalyst, which meanwhile suffered from unfavorable methanation. It was found that Rh single atoms promoted the formation of more oxygen vacancies on the TiO2 support to activate H2O to generate H2 and prohibited the dissociation of H2 compared with Rh clusters, leading to the enhanced activity and selectivity for WGS. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2081–2088, 2017
      PubDate: 2016-11-30T09:21:34.799366-05:
      DOI: 10.1002/aic.15585
       
  • Group additive modeling of substituent effects in monocyclic aromatic
           hydrocarbon radicals
    • Authors: Alper Ince; Hans-Heinrich Carstensen, Maarten Sabbe, Marie-Françoise Reyniers, Guy B. Marin
      Pages: 2089 - 2106
      Abstract: The thermodynamic properties of the unsubstituted and substituted phenyl, phenoxy, anisyl, benzoyl, styryl and benzyl radicals with six substituents (hydroxy, methoxy, formyl, vinyl, methyl, and ethyl) are calculated with the bond additivity corrected (BAC) post-Hartree-Fock G4 method. Bond dissociation energies of monocyclic aromatic hydrocarbons are calculated and used to identify substituent interactions in these radicals. Benson's Group Additivity (GA) scheme is extended to aromatic radicals by defining 6 GAV and 29 NNI parameters through least squares regression to a database of thermodynamic properties of 369 radicals. Comparison between G4/BAC and GA calculated thermodynamic values shows that the standard enthalpies of formation generally agree within 4 kJ mol−1, whereas the entropies and the heat capacities deviate less than 4 J mol−1 K−1. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2089–2106, 2017
      PubDate: 2016-12-09T07:37:33.041398-05:
      DOI: 10.1002/aic.15588
       
  • Multiple isolas in steady-state characteristics of fluidized bed catalytic
           reactors
    • Authors: Katarzyna Bizon
      Pages: 2107 - 2116
      Abstract: Steady-state characteristics of a catalytic fluidized bed reactor are analyzed. A two-phase bubbling model is used for the description of a fluidized bed of a catalyst. Particular attention is focused on the theoretical and technological consequences of a newly observed steady-state behavior. Features of the model are presented in terms of steady-state structures, stability, solution multiplicity, and process efficiency. The possibility of an occurrence of multiple isolas of steady states is demonstrated for two simple kinetic models. Depending on the multiplicity region they belong to, multiple isolas are referred to as first type or second type isolas. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2107–2116, 2017
      PubDate: 2016-12-21T10:35:27.476827-05:
      DOI: 10.1002/aic.15599
       
  • Modeling of the desulfation process in NOx storage and reduction catalysts
    • Authors: Francois-Alexandre Lafossas; Christos Manetas, Ali Mohammadi, Grigorios Koltsakis, Masahide Iida, Kohei Yoshida
      Pages: 2117 - 2127
      Abstract: One of the major challenges for the NOx Storage and Reduction Catalysts technology used in automotive exhaust remains the sulfur susceptibility, which calls for efficient desulfation strategies. The sulfation and desulfation processes are systematically studied via measurements and mathematical modeling of the physicochemical processes. The role of oxygen storage which influences the reducing agents availability for desulfation is explained and a respective reaction model is presented. The bulk oxygen storage component appears to be involved in sulfur storage, which further emphasizes the importance of oxygen–sulfur storage interactions. Next, the observed release of sulfur species under lean mode is discussed along with a proposed reaction mechanism which involves SO2 formation via O2 reaction with elemental sulfur on the surface. The parameters of the complex reaction model are calibrated in order to reproduce the observed trends at least in a qualitative manner. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2117–2127, 2017
      PubDate: 2016-12-21T10:35:33.450547-05:
      DOI: 10.1002/aic.15600
       
  • Efficient adsorption separation of acetylene and ethylene via supported
           ionic liquid on metal-organic framework
    • Authors: Jiawei Wang; Danyan Xie, Zhiguo Zhang, Qiwei Yang, Huabin Xing, Yiwen Yang, Qilong Ren, Zongbi Bao
      Pages: 2165 - 2175
      Abstract: Ionic liquid (IL) supported metal-organic framework (MOF) was utilized to efficiently separate acetylene from ethylene. A common IL, 1-butyl-3-methylimidazolium acetate ([Bmim][OAc]), was encapsulated into a hydrothermally stable MOF, namely MIL-101(Cr). Characterization techniques including FTIR, Powder X-ray diffraction, BET, and thermal gravimetric analysis were used to confirm successful encapsulation of the IL within MIL-101(Cr). Adsorption isotherms of acetylene and ethylene in the IL-encapsulated MOF were tested. From the results, the MOF composite retained a relatively high adsorption capacity. Remarkably, the adsorption selectivity of acetylene/ethylene has dramatically increased from 3.0 to 30 in comparison with the parent MIL-101(Cr). Furthermore, the potential of industrial practice was examined by breakthrough and regeneration experiments. It not only satisfies the industrial production of removal of low level of acetylene from ethylene, but also is notably stable during the adsorption-desorption process. The high designability of ILs combined with richness of MOFs’ structures exploits a novel blueprint for gas separation. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2165–2175, 2017
      PubDate: 2016-11-08T09:45:38.839102-05:
      DOI: 10.1002/aic.15561
       
  • Investigation of the effect of magnetic field on mass transfer parameters
           of CO2 absorption using Fe3O4-water nanofluid
    • Authors: Mohammad Hossein Karimi Darvanjooghi; Maedeh Pahlevaninezhad, Ali Abdollahi, Seyyed Mohammadreza Davoodi
      Pages: 2176 - 2186
      Abstract: In this study, the enhancement of physical absorption of carbon dioxide by Fe3O4-water nanofluid under the influence of AC and DC magnetic fields was investigated. Furthermore, a gas-liquid mass transfer model for single bubble systems was applied to predict mass transfer parameters. The coated Fe3O4 nanoparticles were prepared using co-percipitation method. The results from characterization indicated that the nanoparticles surfaces were covered with hydroxyl groups and nanoparticles diameter were 10–13 nm. The findings showed that the mass transfer rate and solubility of carbon dioxide in magnetic nanofluid increased with an increase in the magnetic field strength. Results indicated that the enhancement of carbon dioxide solubility and average molar flux gas into liquid phase, particularly in the case of AC magnetic field. Moreover, results demonstrated that mass diffusivity of CO2 in nanofluid and renewal surface factor increased when the intensity of the field increased and consequently diffusion layer thickness decreased. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2176–2186, 2017
      PubDate: 2016-11-17T10:55:26.480805-05:
      DOI: 10.1002/aic.15571
       
  • Simultaneous recovery and crystallization control of saline organic
           wastewater by membrane distillation crystallization
    • Authors: Dapeng Lu; Pan Li, Wu Xiao, Gaohong He, Xiaobin Jiang
      Pages: 2187 - 2197
      Abstract: Membrane distillation crystallization (MDC) was introduced and investigated for the simultaneous treatment of saline organic wastewater generated from oil extraction, in this article. The developed process model of MDC for the investigated ternary system was validated by the experiments with good agreement. Under the tested feed ethylene glycol (EG) composition and operation conditions, the highly concentrated EG (residual side, recovery ratio > 98.7%), pure water (permeate side, purity > 99%), pure crystals with narrow crystal-size distribution, and desired morphology were simultaneously manufactured. By this simultaneous recovery of EG and H2O in the feed flow, the overall separation efficiency was enhanced. The impact factors of the crystal properties during MDC were also revealed by comprehensive analysis. Moreover, the diverse metastable zone width and crystal morphology obtained in different feed EG composition indicated the change of the nucleation barrier and the kinetic crystallization control mechanism. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2187–2197, 2017
      PubDate: 2016-11-24T11:25:33.570475-05:
      DOI: 10.1002/aic.15581
       
  • Enzymatic catalyzed reactive dividing wall column: Experiments and model
           validation
    • Authors: Torben Egger; Georg Fieg
      Pages: 2198 - 2211
      Abstract: A novel process for the integration of chemical reaction and product separation is proposed: the enzymatic catalyzed reactive dividing wall column (eRDWC). The eRDWC combines the highly integrated and complex reactive dividing wall column (RDWC) with the use of a very selective enzymatic catalyst. This apparatus enables the simultaneous production and separation of up to 4 pure product streams. Comprehensive experiments with the reference system of a hexanol and butyl acetate transesterification in a DN 65 pilot scale column show the feasibility of stable steady state operations for this process. A rigorous model for the plant design of an eRDWC wall column is developed. The reaction kinetics and vapor-liquid-equilibria for the reference system are measured and implemented in the model. The model is successfully validated using the acquired experimental data. The application of enzymes in continuous reactive distillation processes has the potential to increase the selectivity at milder process conditions. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2198–2211, 2017
      PubDate: 2016-12-21T10:20:45.280853-05:
      DOI: 10.1002/aic.15598
       
  • Association extraction for vitamin E recovery from deodorizer distillate
           by in situ formation of deep eutectic solvent
    • Authors: Lei Qin; Jiangsheng Li, Hongye Cheng, Lifang Chen, Zhiwen Qi, Weikang Yuan
      Pages: 2212 - 2220
      Abstract: An innovative intensified vitamin E (VE) recovery process from the methylated oil deodorizer distillates (MODDs) was proposed, where VE was in situ transferred into a deep eutectic solvent (DES) with an organic salt. To design the process, the chlorine based quaternary ammonium salts were primarily investigated, and [N4,4,4,4]Cl was selected as an association solvent which can efficiently form DES with α-tocopherol of the representative compound of VE. Based on the determined phase diagram of the DES freezing points, four phase regions were classified, and the effect of the [N4,4,4,4]Cl/tocopherol ratio and temperature on the extraction performance and phase transformation was figured out. Moreover, an intensified association extraction process via in situ forming DES of α-tocopherol with [N4,4,4,4]Cl was designed and validated by experiments. VE products were finally obtained from both model MODD (purity of 99.63%) and practical MODDs (purity of>79.18%), which verifies the excellent extraction efficiency for the proposed recovery method. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2212–2220, 2017
      PubDate: 2016-12-24T09:35:25.683843-05:
      DOI: 10.1002/aic.15606
       
  • Effect of small amount of water on the dynamics properties and
           microstructures of ionic liquids
    • Authors: Jing Zhou; Xiaomin Liu, Suojiang Zhang, Xiangping Zhang, Guangren Yu
      Pages: 2248 - 2256
      Abstract: A series of systems of 1-butyl-3-methylimidazolium acetate ([Bmim][Ac]), 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]), and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmim][Tf2N]) with a small amount of water were simulated. Viscosities of systems were obtained by nonequilibrium molecule dynamics simulation and the results show that the viscosities change in different ways: for [Bmim][BF4] and [Bmim][Tf2N], viscosities decrease rapidly in the first stage, and then decrease slowly with the increase of water content. But for [Bmim][Ac], the viscosities increase first and then decrease. The unique phenomenon of [Bmim][Ac] can be attributed to the formation of chain-like structure of anion•••water•••anion•••. Hydrogen bond (HB) interaction between ion pairs is weakened, but the number of HB between water and anions increases with increase of water content. Besides, the microstructures of water in ionic liquids-water systems were compared and found that the distribution of water is more concentrated in [Bmim][Tf2N]-H2O system, while it is isotropy in [Bmim][Ac]-H2O system. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2248–2256, 2017
      PubDate: 2016-12-07T09:20:54.835476-05:
      DOI: 10.1002/aic.15594
       
  • Capturing the non-spherical shape of granular media and its trickle flow
           characteristics using fully-Lagrangian method
    • Authors: Shungo Natsui; Ryota Nashimoto, Tatsuya Kikuchi, Ryosuke O. Suzuki, Hifumi Takai, Ko-ichiro Ohno, Sohei Sukenaga
      Pages: 2257 - 2271
      Abstract: We performed a numerical analysis for simulating granular media structures containing non-spherical elements and the liquid trickle flow characteristics of such structures. Fully-Lagrangian numerical simulation methods can track all motion information for solid or liquid elements at each point in time. We introduced suitable compressibility to moving particle semi-implicit (MPS) and performed individual packing behavior calculations for non-spherical elements, based on discrete element method (DEM) with expanded functions. Rigid bodies-DEM is a method using a DEM contact force model that is expanded to handle the motion of freely shaped solids. It expresses complex shapes to enable low calculation costs and intuitive mounting. We used the boundary for the granular media configured with non-spherical elements to implement a trickle flow simulation based on weakly compressible-MPS. Even for elements of equal volume, different shapes changed the liquid passage velocity and hold-up amount. The mean downflow velocity of the liquid phase was not always dependent on the void fraction. For the plane of projection, we obtained a good correlation with the mean downflow velocity in each packed structure, and successfully performed arrangements according to the new liquid-passage shape coefficient. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2257–2271, 2017
      PubDate: 2016-10-27T19:50:40.34057-05:0
      DOI: 10.1002/aic.15538
       
  • Optical methods to investigate the enhancement factor of an
           oxygen-sensitive colorimetric reaction using microreactors
    • Authors: Lixia Yang; Nicolas Dietrich, Gilles Hébrard, Karine Loubière, Christophe Gourdon
      Pages: 2272 - 2284
      Abstract: Visualization of mass transfer is a powerful tool to improve understanding of local phenomenon. The use of an oxygen-sensitive dye (colorimetric technique) (Dietrich et al., Chem Eng Sci. 2013; 100:172–182) has showed its relevancy for locally visualizing and characterizing gas–liquid mass transfer at different scales (Kherbeche et al., Chem Eng Sci. 2013; 100: 515–528; Yang et al., Chem Eng Sci. 2016; 143:364–368). At present, the occurrence of a possible enhancement of the gas–liquid mass transfer by this reaction has not been yet demonstrated. This article aims at filling this gap by evaluating the Hatta number Ha and the enhancement factor E associated with the oxygen colorimetric reaction when implementing in milli/micro channels. For that, as data on the kinetic of the colorimetric reaction are seldom in the literature, the reaction characteristic time was first estimated by carrying out experiments in a microchannel equipped with a micromixer. The diffusion coefficients of dihydroresorufin and O2 were then determined by implementing two original optical methods in a specific coflow microchannel device, coupled with theoretical modelling. The knowledge of these parameters enabled at last to demonstrate that no enhancement of the gas–liquid mass transfer by this colorimetric reaction existed. Complementary information about the reliability of the colorimetric technique to characterize the gas–liquid mass transfer in milli/micro systems was also given. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2272–2284, 2017
      PubDate: 2016-10-31T14:15:37.399231-05:
      DOI: 10.1002/aic.15547
       
  • Phase separation of gas–liquid two-phase stratified and plug flows in
           multitube T-junction separators
    • Authors: Limin Yang; Jiahao Wang, Zhenying Zhao, Shengbo Xu, Barry J Azzopardi, Hong Wang
      Pages: 2285 - 2292
      Abstract: Using air and water as the working fluids, phase separation phenomena for stratified and plug flows at inlet were investigated experimentally, at a simple T-junction and specifically designed multitube T-junction separators with two or three layers. The results show that for these two flow patterns the separation efficiency of the two phases for any multitube T-junction separator is much higher than that of the simple T-junction. Increasing the number of connecting tubes in the multitube T-junction separator can increase the separation efficiency. Generally, for stratified flow, complete separation of the two phases can be achieved by the two-layer multitube T-junction separator with five or more connecting tubes and by the three-layer separator; increasing the gas flow rate, the liquid flow rate, or the mixture velocity under plug flow is detrimental to phase separation with a drop in peak separation efficiency. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2285–2292, 2017
      PubDate: 2016-11-05T10:46:45.001439-05:
      DOI: 10.1002/aic.15552
       
  • Droplet breakage and coalescence in liquid–liquid dispersions:
           Comparison of different kernels with EQMOM and QMOM
    • Authors: Dongyue Li; Zhengming Gao, Antonio Buffo, Wioletta Podgorska, Daniele L. Marchisio
      Pages: 2293 - 2311
      Abstract: Droplet coalescence and breakage in turbulent liquid–liquid dispersions is simulated by using computational fluid dynamics (CFD) and population balance modeling. The multifractal (MF) formalism that takes into account internal intermittency was here used for the first time to describe breakage and coalescence in a surfactant-free dispersion. The log-normal Extended Quadrature Method of Moments (EQMOM) was for the first time coupled with a CFD multiphase solver. To assess the accuracy of the model, predictions are compared with experiments and other models (i.e., Coulalogou and Tavlarides kernels and Quadrature Method of Moments [QMOM]). EQMOM and QMOM resulted in similar predictions, but EQMOM provides a continuous reconstruction of the droplet-size distribution. Transient predictions obtained with the MF kernels result in a better agreement with the experiments. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2293–2311, 2017
      PubDate: 2016-11-08T09:45:35.605725-05:
      DOI: 10.1002/aic.15557
       
  • A critical look into effects of electrode pore morphology in solid oxide
           fuel cells
    • Authors: Yinghua Niu; Weiqiang Lv, Gaofeng Rao, Weidong He, Jiarui He
      Pages: 2312 - 2317
      Abstract: Knudsen diffusion, an important form of gas transport in sub-micro/nanoscale porous electrodes of solid oxide fuel cells (SOFCs), is evaluated typically based on the assumption of isotropic cross-sections of electrode pores. As a consequence, errors are induced in the evaluation of gas transport and polarization loss of SOFCs with irregular, anisotropic pore morphology. Here, a numerical model is derived to investigate the impact of pore morphology on Knudsen diffusivity and effective total diffusivity in porous SOFC electrodes. Based on the model, the correlation between pore morphology and important parameters of SOFCs, including limiting current density (LCD) and concentration polarization (CP), is evaluated. As the aspect ratio of pore cross-section increases, the gas diffusivity in SOFC electrodes decreases, and then nontrivial variations in LCD and CP are induced. This work facilitates the accurate evaluation of gas transport in SOFCs as well as the rational design of electrode microstructure of SOFCs. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2312–2317, 2017
      PubDate: 2016-11-14T11:42:15.169473-05:
      DOI: 10.1002/aic.15554
       
  • Steady flow of gas and decomposing particles in a vertical feed tube for
           applications in biomass pyrolysis
    • Authors: Yenhan Lin; Triantafillos J. Mountziaris, Jeffrey M. Davis
      Pages: 2318 - 2334
      Abstract: Using the approach of interacting and interpenetrating continua, a one-dimensional model is developed for the gravity-driven flow of particles and gas through a vertical standpipe. The gas and particle phases exchange momentum through the drag force, and mass is exchanged between the phases as the particles decompose to gaseous products. On simultaneously integrating the differential equations expressing conservation of mass and momentum for each of the two phases, the theory yields the particle and gas flow rates, the pressure profile, and the particle size and void fraction distributions. Performance diagrams are constructed, and preferred operating conditions are identified that provide steady flow, generate no backpressure, or avoid a transition to moving bed flow or reversed gas flow. The admissible range of operating conditions is found to increase with the particle decomposition rate, and the results may guide the selection of operating conditions in practice. Applications are made to biomass pyrolysis in a catalytic reactor. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2318–2334, 2017
      PubDate: 2016-11-15T11:43:48.349645-05:
      DOI: 10.1002/aic.15558
       
  • On the 2D nature of flow dynamics in opposed jets mixers
    • Authors: Nelson D. Gonçalves; Hélder M. Salvador, Cláudio P. Fonte, Madalena M. Dias, José Carlos B. Lopes, Ricardo J. Santos
      Pages: 2335 - 2347
      Abstract: Confined impinging jets (CIJs) are reactors used in processes that require fast mixing. In such equipment two fluids are injected from opposite sides of a chamber, impinging into each other and forming flow structures that enable an effective mixing and reaction. The turbulence analysis shows that the energy is injected from smaller scales, having approximately the injectors width, that feed larger scale structures up to larger vortices that occupy the entire mixing chamber width. This energy distribution has an inverse energy cascade, i. e. it is an inversion of the traditional description of homogeneous 3D turbulence. The typical flow scales of 2D CIJs are clearly shown in this work to be linked to the 2D turbulence energy spectrum and to integral scales of turbulence. Moreover, the turbulence mechanisms in 3D CIJs at transitional flow regimes are shown to be similar to 2D CIJs. This is to our knowledge the first demonstration of 2D turbulence in an industrial mixer/reactor. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2335–2347, 2017
      PubDate: 2016-11-15T11:43:42.716793-05:
      DOI: 10.1002/aic.15566
       
  • Investigating the liquid film characteristics of gas–liquid swirling
           flow using ultrasound doppler velocimetry
    • Authors: Fachun Liang; Zhaojun Fang, Jing Chen, Shitao Sun
      Pages: 2348 - 2357
      Abstract: A novel gas–liquid two-phase flow metering method was proposed. A spiral vane mounted in the inner pipe was used to transform inlet flow patterns into gas–liquid swirling annular flow. The thickness and velocity profile of liquid film were measured by ultrasound Doppler velocimetry. The liquid flow rates were obtained by integrating of velocity profile during the liquid film zone. Experiments were carried out in an air–water two-phase flow loop and an ultrasonic transducer was installed under the bottom of the test section with the Doppler angle of 70°. The flow patterns included stratified wavy, annular, and slug flows. Compared with non-swirling flow, the liquid film thickness at the bottom reduces greatly. The measurement accuracy of liquid flow rate was independent of inlet flow patterns, gas and liquid velocities. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2348–2357, 2017
      PubDate: 2016-11-15T11:14:19.303814-05:
      DOI: 10.1002/aic.15570
       
  • Hydrodynamic drift ratchet scalability
    • Authors: James W. Herringer; Daniel R. Lester, Graham E. Dorrington, Gary Rosengarten, James G. Mitchell
      Pages: 2358 - 2366
      Abstract: The hydrodynamic drift ratchet provides a novel means to continuously separate particles at the microscale, based on particle size. Separation arises from a combination of diffusion and particle-wall hydrodynamic interactions. As there are currently no verified experiments, our aim is to determine numerically how these systems scale so that appropriate experiments can be designed. Using nondimensional variables, we derive the correct scaling parameters governing drift ratchets by simulating individual particle motion using a model that treats the particle dynamics at pore walls as elastic reflections. While our model does not quantitatively resolve the detailed hydrodynamic interactions, we show that it does recover the correct scaling behavior for these interactions. Our simulations demonstrate that the drift velocity relative to the characteristic pore size is independent of pore size if all the relevant nondimensional groups remain constant. Dynamic similarity can be used to facilitate the appropriate design and testing protocols for experiments. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2358–2366, 2017
      PubDate: 2016-11-17T10:50:36.594815-05:
      DOI: 10.1002/aic.15569
       
  • Droplet formation at megahertz frequency
    • Authors: John C. Miers; Wenchao Zhou
      Pages: 2367 - 2377
      Abstract: Droplet formation has been a fascinating subject to scientists for centuries due to its natural beauty and importance to both scientific and industrial applications, such as inkjet printing, reagent deposition, and spray cooling. However, the droplet generation frequency of common drop-on-demand (DOD) jetting techniques is mostly limited to ∼10 kHz. This article presents an investigation of the possibility of jetting at megahertz frequencies to boost the productivity of DOD material deposition by ∼100 times. The focus of this article is to understand the limitations of generating droplets at a megahertz frequency and to explore possible solutions for overcoming these limitations. A numerical model is first developed for the simulation of droplet formation dynamics. The numerical model is validated against available experimental data from the literature. Aided by insights gained from scaling analysis, the validated model is then used to study the effects of different parameters on high frequency jetting. The study finds energy density input to the nozzle is the key to achieve megahertz frequency droplet breakup. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2367–2377, 2017
      PubDate: 2016-11-24T10:40:38.627175-05:
      DOI: 10.1002/aic.15578
       
  • Nonlinear time-series analysis of optical signals to identify multiphase
           flow behavior in microchannels
    • Authors: Dongyue Peng; Feng Xin, Lexiang Zhang, Zuopeng Gao, Weihua Zhang, Yuexing Wang, Xiaodong Chen, Yi Wang
      Pages: 2378 - 2385
      Abstract: This study provides an insight into the instability and irregularity of multiphase flows in microchannels. Using a homemade optical measuring system, time series related to two-phase flow dynamics under different operating conditions, fluids, and channel lengths were collected and analyzed via a nonlinear characteristic parameter, Kolmogorov entropy (KE). Our results reveal that higher KE corresponds to unstable flow behavior, while lower KE refers to steady flow behavior; higher KE values appear at comparatively low or high gas flow rates, and most Taylor flow regime appeared at proper operating conditions with small KE. An equation derived based on the definition of KE is proposed to better understand KE characteristics, which include bubble break-up impact and gas/liquid flow rate ratio. Predictions from the proposed analytical equation agree with experimental results, suggesting that the equation effectively identifies unstable flows and can be used to ensure stable and predictable multiphase flows in microchannels. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2378–2385, 2017
      PubDate: 2016-11-24T11:25:28.284281-05:
      DOI: 10.1002/aic.15584
       
  • Numerical investigation on CO2 absorbed in aqueous
           N-methyldiethanolamine + piperazine
    • Authors: Jicai Huang; Maoqiong Gong, Zhaohu Sun, Xueqiang Dong, Jun Shen, Jianfeng Wu
      Pages: 2386 - 2393
      Abstract: A multiphase and multicomponent mass transfer model of CO2 absorbed in aqueous N-methyldiethanolamine and piperazine (PZ) was built in the study. In the model, a simple method of mass transfer between phases was proposed. Besides, the hydrodynamics, thermodynamics, and complex reversible chemical reaction were considered simultaneously. The model was validated by comparing with the previous experimental data which showed that simulated results can represent the experimental data with reasonable accuracy. Based on the model, the effects of gas velocity, liquid load and CO2 loading on the absorption rate, and enhancement factor were analyzed. Model results showed that the enhancement factor increased with a rising gas velocity while decreased with a rising liquid load or CO2 loading. The change of enhancement factor with CO2 loading was similar to that of equilibrium concentration of PZ which indicated that PZ was significant to the absorption process. Furthermore, the distributions of specie concentrations were discussed in detail. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2386–2393, 2017
      PubDate: 2016-11-24T11:35:26.011333-05:
      DOI: 10.1002/aic.15590
       
  • Experimental investigation of interfacial mass transfer mechanisms for a
           confined high-reynolds-number bubble rising in a thin gap
    • Authors: Matthieu Roudet; Anne-Marie Billet, Sébastien Cazin, Frédéric Risso, Véronique Roig
      Pages: 2394 - 2408
      Abstract: Interfacial mass transfer is known to be enhanced for confined bubbles due to the efficiency of the transfer in the thin liquid films between them and the wall. In the present experimental investigation, the mechanisms of gas–liquid mass transfer are studied for isolated bubbles rising at high Reynolds number in a thin gap. A planar laser induced fluorescence (PLIF) technique is applied with a dye the fluorescence of which is quenched by dissolved oxygen. The aim is to measure the interfacial mass fluxes for pure oxygen bubbles of various shapes and paths rising in water at rest. In the wakes of the bubbles, patterns due to the presence of dissolved oxygen are observed on PLIF images. They reveal the contrasted contributions to mass transfer of two different regions of the interface. The flow around a bubble consists of both two thin liquid films between the bubble and the walls of the cell and an external high-Reynolds-number in-plane flow surrounding the bubble. Mass transfer mechanisms associated to both regions are discussed. Measurement of the concentration of dissolved oxygen is a difficult task due to the nonlinear relation between the fluorescence intensity and the concentration in the gap. It is however possible to accurately measure the global mass flux transferred through the bubble interface. It is determined from the fluorescence intensity recorded in the wakes when the oxygen distribution has been made homogeneous through the gap by diffusion. Assuming a reasonable distribution of oxygen concentration through the gap at short time also allows a measurement of the mass fluxes due to the liquid films. A discussion of the results points out the specific physics of mass transfer for bubbles confined between two plates as compared to bubbles free to move in unconfined flows. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2394–2408, 2017
      PubDate: 2016-11-28T19:01:54.160195-05:
      DOI: 10.1002/aic.15562
       
  • Turbulent mixing in the confined swirling flow of a multi-inlet vortex
           reactor
    • Authors: Zhenping Liu; Emmanuel Hitimana, Michael G. Olsen, James C. Hill, Rodney O. Fox
      Pages: 2409 - 2419
      Abstract: Turbulent mixing in the confined swirling flow of a multi-inlet vortex reactor (MIVR) was investigated using planar laser induced fluorescence (PLIF). The investigated Reynolds numbers based on the bulk inlet velocity ranged from 3290 to 8225, and the Schmidt number of the passive scalar was 1250. Measurements were taken in the MIVR at three different heights (¼, ½, and ¾ planes). The mixing characteristics and performance of the MIVR were investigated using instantaneous PLIF fields and pointwise statistics such as mixture fraction mean, variance, and one-point concentration probability density function. It was found that the scalar is stretched along velocity streamlines, forming a spiral mixing pattern in the free-vortex region. In the forced-vortex region, mixing intensifies as the turbulent fluctuations increase significantly there. The mixing mechanisms in the MIVR were revealed by identifying specific segregation zones. At Re = 8225 the mixing in the free-vortex region was dominated by both large-scale structures and turbulent diffusion, while in the forced-vortex region mixing is dominated by turbulent diffusion. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2409–2419, 2017
      PubDate: 2016-11-29T10:50:47.429621-05:
      DOI: 10.1002/aic.15572
       
  • CFD studies coupling hydrodynamics and solid-liquid mass transfer in slug
           flow for matter removal from tube walls
    • Authors: Mónica C. F. Silva; José D. P. Araújo, João B. L. M. Campos
      Pages: 2420 - 2439
      Abstract: Organic matter deposition on internal surfaces constitutes a drawback that impairs the efficiency of several industrial processes. To overcome this problem, sparging a train of bubbles could be useful since its presence strongly increases the wall shear stress. A detailed numerical mass-transfer study between a finite soluble wall and the liquid around a rising Taylor bubble was performed, simultaneously solving velocity and concentration fields. The bubble passage throws solute backward and is responsible for radial dispersion. There is also an increase in the transfer rate with enhancements between 10 and 20% (depending on liquid average velocity and bubble length) compared to single-phase flow. Mass-transfer coefficients along the different hydrodynamic regions around the bubble nose, liquid film, and wake were characterized and their values compared with those from literature. The results suggest a promising potential of bubble train flow to enhance organic matter removal from walls in biological systems. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2420–2439, 2017
      PubDate: 2016-12-24T09:55:29.966009-05:
      DOI: 10.1002/aic.15610
       
 
 
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