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  Subjects -> ENGINEERING (Total: 2336 journals)
    - CHEMICAL ENGINEERING (200 journals)
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    - ENGINEERING (1225 journals)
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ENGINEERING (1225 journals)            First | 1 2 3 4 5 6 7 | Last

Showing 201 - 400 of 1205 Journals sorted alphabetically
CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Current Graphene Science     Hybrid Journal  
Current Nanomaterials     Hybrid Journal  
Current Science     Open Access   (Followers: 69)
Dams and Reservoirs     Hybrid Journal   (Followers: 5)
Data Handling in Science and Technology     Full-text available via subscription   (Followers: 5)
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 28)
Designed Monomers and Polymers     Open Access   (Followers: 2)
Designs     Open Access  
Designs, Codes and Cryptography     Hybrid Journal   (Followers: 7)
Development Engineering     Open Access  
Developments in Clay Science     Full-text available via subscription   (Followers: 1)
Developments in Geotechnical Engineering     Full-text available via subscription   (Followers: 5)
Developments in Mineral Processing     Full-text available via subscription   (Followers: 3)
Diálogos Interdisciplinares     Open Access  
Diamond Light Source Proceedings     Full-text available via subscription  
Diffusion Foundations     Full-text available via subscription   (Followers: 3)
Digital Signal Processing     Hybrid Journal   (Followers: 24)
Dinamika Rekayasa     Open Access  
Discrete Optimization     Full-text available via subscription   (Followers: 6)
Doct-Us Journal     Open Access  
Documents pour l'histoire des techniques     Open Access   (Followers: 1)
Dyes and Pigments     Hybrid Journal   (Followers: 2)
DYNA Minas     Open Access  
Dynamical Systems : An International Journal     Hybrid Journal  
E&S Engineering and Science     Open Access  
El Hombre y la Máquina     Open Access  
Electromagnetics     Hybrid Journal   (Followers: 8)
Electrophoresis     Hybrid Journal   (Followers: 18)
Elementos     Open Access  
Elsevier Geo-Engineering Book Series     Full-text available via subscription   (Followers: 3)
Elsevier Ocean Engineering Series     Full-text available via subscription   (Followers: 1)
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 46)
Emitter : International Journal of Engineering Technology     Open Access   (Followers: 1)
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations     Open Access   (Followers: 1)
Energies     Open Access   (Followers: 4)
Energy and Power Engineering     Open Access   (Followers: 21)
Energy Conversion and Management     Hybrid Journal   (Followers: 11)
Energy Engineering     Full-text available via subscription   (Followers: 9)
Energy for Sustainable Development     Hybrid Journal   (Followers: 9)
Energy Procedia     Open Access   (Followers: 2)
Energy Science & Engineering     Open Access   (Followers: 5)
Energy Science and Technology     Open Access   (Followers: 12)
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects     Hybrid Journal   (Followers: 1)
Energy Sources, Part B: Economics, Planning, and Policy     Hybrid Journal   (Followers: 6)
Energy Systems     Hybrid Journal   (Followers: 13)
ENGEVISTA     Open Access   (Followers: 1)
ENGI : Revista Electrónica de la Facultad de Ingenieria     Open Access   (Followers: 1)
Engineer : Journal of the Institution of Engineers, Sri Lanka     Open Access  
Engineering     Open Access   (Followers: 2)
Engineering & Technology     Hybrid Journal   (Followers: 23)
Engineering : The official journal of the Chinese Academy of Engineering and Higher Education Press     Open Access   (Followers: 1)
Engineering Analysis with Boundary Elements     Hybrid Journal   (Followers: 1)
Engineering Computations     Hybrid Journal   (Followers: 4)
Engineering Economics     Open Access   (Followers: 5)
Engineering Economist, The     Hybrid Journal   (Followers: 5)
Engineering Failure Analysis     Hybrid Journal   (Followers: 67)
Engineering Geology     Hybrid Journal   (Followers: 9)
Engineering International     Open Access  
Engineering Management Journal     Hybrid Journal   (Followers: 21)
Engineering Management Research     Open Access   (Followers: 7)
Engineering Management Reviews     Open Access   (Followers: 1)
Engineering Optimization     Hybrid Journal   (Followers: 15)
Engineering Science and Technology, an International Journal     Open Access   (Followers: 1)
Engineering Sciences     Open Access   (Followers: 1)
Engineering Studies     Hybrid Journal  
Engineering With Computers     Hybrid Journal   (Followers: 6)
Engineering, Technology & Applied Science Research     Open Access  
Entramado     Open Access  
Entropy     Open Access   (Followers: 5)
Environmental & Engineering Geoscience     Full-text available via subscription   (Followers: 4)
Environmental and Ecological Statistics     Hybrid Journal   (Followers: 6)
Environmetrics     Hybrid Journal  
Épités - Épitészettudomány     Full-text available via subscription   (Followers: 1)
EPJ Photovoltaics     Open Access   (Followers: 5)
Ergonomics in Design: The Quarterly of Human Factors Applications     Hybrid Journal   (Followers: 17)
ESAIM: Control Optimisation and Calculus of Variations     Full-text available via subscription   (Followers: 1)
ESAIM: Mathematical Modelling and Numerical Analysis     Full-text available via subscription   (Followers: 6)
ESAIM: Proceedings     Open Access   (Followers: 1)
Estuaries and Coasts     Hybrid Journal   (Followers: 18)
European Journal of Combinatorics     Full-text available via subscription   (Followers: 5)
European Journal of Engineering Education     Hybrid Journal   (Followers: 4)
European Journal of Lipid Science and Technology     Hybrid Journal   (Followers: 1)
European Journal of Mass Spectrometry     Full-text available via subscription   (Followers: 16)
European Medical Device Technology     Full-text available via subscription   (Followers: 4)
European Physical Journal - Applied Physics     Full-text available via subscription   (Followers: 16)
European Transport Research Review     Open Access   (Followers: 21)
Evolutionary Intelligence     Hybrid Journal   (Followers: 1)
Evolving Systems     Hybrid Journal  
Exacta     Open Access  
Experimental Techniques     Hybrid Journal   (Followers: 56)
Experiments in Fluids     Hybrid Journal   (Followers: 13)
Fibers and Polymers     Full-text available via subscription   (Followers: 6)
Filtration & Separation     Full-text available via subscription   (Followers: 5)
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 4)
Fire Science Reviews     Open Access   (Followers: 8)
Flexible Services and Manufacturing Journal     Hybrid Journal   (Followers: 1)
Flow, Turbulence and Combustion     Hybrid Journal   (Followers: 26)
Fluid Dynamics     Hybrid Journal   (Followers: 14)
Fluid Dynamics Research     Full-text available via subscription   (Followers: 12)
Fluid Phase Equilibria     Hybrid Journal   (Followers: 4)
Focus on Catalysts     Full-text available via subscription  
Focus on Pigments     Full-text available via subscription   (Followers: 4)
Focus on Powder Coatings     Full-text available via subscription   (Followers: 5)
Focus on Surfactants     Full-text available via subscription   (Followers: 4)
Food Engineering Reviews     Hybrid Journal   (Followers: 3)
Food Science and Technology     Open Access   (Followers: 3)
Formación Universitaria     Open Access   (Followers: 4)
FORMakademisk     Open Access  
Formal Methods in System Design     Hybrid Journal   (Followers: 7)
Forschung     Hybrid Journal   (Followers: 1)
Forschung im Ingenieurwesen     Hybrid Journal   (Followers: 1)
Foundations and Trends in Systems and Control     Full-text available via subscription  
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 7)
Foundations and Trends® in Electronic Design Automation     Full-text available via subscription  
Foundations of Science     Hybrid Journal   (Followers: 1)
Frontiers in Energy     Hybrid Journal   (Followers: 4)
Frontiers in Geotechnical Engineering     Open Access   (Followers: 3)
Frontiers of Environmental Science & Engineering     Hybrid Journal   (Followers: 4)
Frontiers of Nanoscience     Full-text available via subscription   (Followers: 1)
Fuel and Energy Abstracts     Full-text available via subscription   (Followers: 6)
Fuel Cells     Hybrid Journal   (Followers: 6)
Fuel Cells Bulletin     Full-text available via subscription   (Followers: 5)
Fusion Engineering and Design     Hybrid Journal   (Followers: 10)
Fuzzy Information and Engineering     Open Access   (Followers: 3)
Fuzzy Sets and Systems     Hybrid Journal   (Followers: 4)
Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards     Hybrid Journal   (Followers: 9)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 183)
Geotechnical Testing Journal     Full-text available via subscription   (Followers: 11)
Géotechnique     Hybrid Journal   (Followers: 29)
Geothermics     Hybrid Journal   (Followers: 7)
Glass Technology - European Journal of Glass Science and Technology Part A     Full-text available via subscription   (Followers: 4)
Global Journal of Engineering Research     Full-text available via subscription  
Global Perspective on Engineering Management     Open Access   (Followers: 3)
GPS Solutions     Hybrid Journal   (Followers: 23)
Graphs and Combinatorics     Hybrid Journal   (Followers: 7)
Grass and Forage Science     Hybrid Journal   (Followers: 8)
Great Circle: Journal of the Australian Association for Maritime History, The     Full-text available via subscription   (Followers: 8)
Groundwater for Sustainable Development     Full-text available via subscription   (Followers: 3)
Handai Nanophotonics     Full-text available via subscription  
Handbook of Adhesives and Sealants     Full-text available via subscription   (Followers: 2)
Handbook of Sensors and Actuators     Full-text available via subscription   (Followers: 10)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
Heat Exchangers     Open Access   (Followers: 3)
Heat Transfer - Asian Research     Hybrid Journal   (Followers: 12)
Heat Transfer Engineering     Hybrid Journal   (Followers: 30)
Historical Records of Australian Science     Hybrid Journal   (Followers: 2)
Human Factors in Ergonomics & Manufacturing     Hybrid Journal   (Followers: 12)
IBM Journal of Research and Development     Hybrid Journal   (Followers: 18)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 84)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 71)
IEEE Communications Magazine     Full-text available via subscription   (Followers: 91)
IEEE Engineering Management Review     Full-text available via subscription   (Followers: 53)
IEEE Geoscience and Remote Sensing Letters     Hybrid Journal   (Followers: 159)
IEEE Industry Applications Magazine     Full-text available via subscription   (Followers: 34)
IEEE Instrumentation & Measurement Magazine     Full-text available via subscription   (Followers: 82)
IEEE Journal of Biomedical and Health Informatics     Hybrid Journal   (Followers: 15)
IEEE Journal of Oceanic Engineering     Hybrid Journal   (Followers: 13)
IEEE Journal of Selected Topics in Quantum Electronics     Hybrid Journal   (Followers: 8)
IEEE Journal of Selected Topics in Signal Processing     Hybrid Journal   (Followers: 39)
IEEE Journal of Solid-State Circuits     Full-text available via subscription   (Followers: 22)
IEEE Journal on Selected Areas in Communications     Hybrid Journal   (Followers: 23)
IEEE Latin America Transactions     Full-text available via subscription   (Followers: 4)
IEEE Microwave and Wireless Components Letters     Hybrid Journal   (Followers: 23)
IEEE Microwave Magazine     Full-text available via subscription   (Followers: 38)
IEEE Potentials     Full-text available via subscription   (Followers: 31)
IEEE Signal Processing Letters     Hybrid Journal   (Followers: 46)
IEEE Spectrum     Full-text available via subscription   (Followers: 204)
IEEE Technology and Society Magazine     Full-text available via subscription   (Followers: 7)
IEEE Transactions on Advanced Packaging     Full-text available via subscription   (Followers: 7)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 64)
IEEE Transactions on Applied Superconductivity     Hybrid Journal   (Followers: 5)
IEEE Transactions on Automation Science and Engineering     Full-text available via subscription   (Followers: 11)
IEEE Transactions on Circuits and Systems II: Express Briefs     Hybrid Journal   (Followers: 21)
IEEE Transactions on Components and Packaging Technologies     Full-text available via subscription   (Followers: 15)
IEEE Transactions on Control Systems Technology     Hybrid Journal   (Followers: 70)
IEEE Transactions on Education     Hybrid Journal   (Followers: 10)
IEEE Transactions on Electronics Packaging Manufacturing     Full-text available via subscription   (Followers: 22)
IEEE Transactions on Energy Conversion     Hybrid Journal   (Followers: 17)
IEEE Transactions on Engineering Management     Hybrid Journal   (Followers: 35)
IEEE Transactions on Evolutionary Computation     Hybrid Journal   (Followers: 8)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 28)
IEEE Transactions on Instrumentation and Measurement     Hybrid Journal   (Followers: 69)
IEEE Transactions on Intelligent Transportation Systems     Hybrid Journal   (Followers: 9)
IEEE Transactions on Knowledge and Data Engineering     Hybrid Journal   (Followers: 33)
IEEE Transactions on Magnetics     Hybrid Journal   (Followers: 14)
IEEE Transactions on Microwave Theory and Techniques     Hybrid Journal   (Followers: 29)
IEEE Transactions on Nuclear Science     Hybrid Journal   (Followers: 10)
IEEE Transactions on Plasma Science     Hybrid Journal   (Followers: 10)
IEEE Transactions on Power Delivery     Hybrid Journal   (Followers: 18)
IEEE Transactions on Professional Communication     Hybrid Journal   (Followers: 10)
IEEE Transactions on Reliability     Hybrid Journal   (Followers: 43)
IEEE Transactions on Semiconductor Manufacturing     Hybrid Journal   (Followers: 8)
IEEE Transactions on Signal Processing     Hybrid Journal   (Followers: 76)
IEEE Transactions on Vehicular Technology     Hybrid Journal   (Followers: 4)
IEEE Vehicular Technology Magazine     Full-text available via subscription   (Followers: 7)
IEEE/ACM Transactions on Computational Biology and Bioinformatics     Hybrid Journal   (Followers: 16)
IERI Procedia     Open Access   (Followers: 1)
IET Circuits, Devices & Systems     Hybrid Journal   (Followers: 18)

  First | 1 2 3 4 5 6 7 | Last

Journal Cover AIChE Journal
  [SJR: 1.122]   [H-I: 120]   [32 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  [1597 journals]
  • Novel Aeration of a Large-Scale Flat Sheet MBR: a CFD and Experimental
    • Authors: Bing Wang; Kaisong Zhang, Robert W. Field
      Abstract: Having previously established that the hydrodynamic effect introduced by slug bubbles is more effective and economic in fouling amelioration in flat sheet MBRs (FSMBR) than conventional bubbling, this work is focused on its implementation in a commercial FSMBR. The overall objective is to enhance the hydrodynamic effect on fouling control through the use of two-stage large-sized bubble development (coalescence and split). Computational Fluid Dynamics (CFD) was used to predict hydrodynamic features and substantial agreement was observed with experimental measurements. The critical height for bubble development space was determined to be circa 250 mm. Slug bubbles could be introduced into 14 channels, resulting in 6 fold stronger shear stress than that from single bubbles. Energy demand could be reduced by circa 50% compared with industry average usage and the shear stresses developed would, for most applications, be sufficient to ameliorate fouling. Furthermore, the specific air demand per permeate would be halved. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-15T11:45:55.317868-05:
      DOI: 10.1002/aic.16164
  • Scale-Dependent Nonequilibrium Features in a Bubbling Fluidized Bed
    • Authors: Haifeng Wang; Yanpei Chen, Wei Wang
      Abstract: We investigate experimentally the nonequilibrium features in a pseudo 2D bubbling fluidized bed. Velocities of individual particles are measured by using a particle tracking velocimetry (PTV) method, and void fractions are obtained with the Voronoi tessellation. A bimodal shape of probability density function (PDF) for particle vertical velocity is found in not only time-averaged but also time-varying statistics, which is caused by the transition between the dense and dilute phases and breaks the local-equilibrium assumption in continuum modeling of fluidized beds. The results of time-varying radial distribution function and voidage distribution also confirm this finding. Moreover, the analysis of voidage, particle velocity, granular temperature and turbulent kinetic energy of particles shows that there is no scale-independent plateau over the interface, and it seems hard to find a scale-independent plateau to separate the micro- and meso-scales of fluidized beds, which require sub-grid meso-scale modeling for continuum or coarse-graining methods of gas-fluidized systems. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-15T11:45:29.469291-05:
      DOI: 10.1002/aic.16163
  • Effect of Pickering Stabilization on Radical Entry in Emulsion
    • Authors: Barthélémy Brunier; Nida Sheibat-Othman, Yves Chevalier, Élodie Bourgeat-Lami
      Abstract: The production of latexes stabilized by solid particles, so-called Pickering stabilizers, has attracted considerable attention due to its benefits, including the enhanced mechanical properties of the polymer films. Clays for instance were found to enhance particle stabilization in emulsion polymerization, in a comparable way to conventional surfactants. Their concentration thus determines the polymer particles size and number, and consequently the reaction rate. In this work, we investigate the impact of the presence of such rigid and big platelets at the polymer particle's surface on radical exchange between the aqueous phase and the polymer particles. It was found for the system underhand, that the average number of radicals per particle (n-) was independent of the stabilizer layer. Therefore, a radical capture model independent of the clay concentration could be used to simulate reactions involving different clay concentrations and predict the evolution of the monomer conversion, particle size, and n-. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-14T11:11:23.290059-05:
      DOI: 10.1002/aic.16159
  • Machine learning for crystal identification and discovery
    • Authors: Matthew Spellings; Sharon C. Glotzer
      Abstract: As computers get faster, researchers — not hardware or algorithms — become the bottleneck in scientific discovery. Computational study of colloidal self-assembly is one area that is keenly affected: even after computers generate massive amounts of raw data, performing an exhaustive search to determine what (if any) ordered structures occur in a large parameter space of many simulations can be excruciating. We demonstrate how machine learning can be applied to discover interesting areas of parameter space in colloidal self-assembly. We create numerical fingerprints — inspired by bond orientational order diagrams — of structures found in self-assembly studies and use these descriptors to both find interesting regions in a phase diagram and identify characteristic local environments in simulations in an automated manner for simple and complex crystal structures. Utilizing these methods allows analysis to keep up with the data generation ability of modern high-throughput computing environments. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-14T11:11:07.791957-05:
      DOI: 10.1002/aic.16157
  • Controllable Fabrication and Catalytic Performance of Nanosheet HZSM-5
           Films by Vertical Secondary Growth
    • Authors: Yajie Tian; Hong Liu, Li Wang, Xiangwen Zhang, Guozhu Liu
      Abstract: Nanosheet HZSM-5 film vertically grown on the substrate with the tailorable macro- and meso-pores between the layers of nanosheets is hydrothermally synthesized by seed-assisted secondary growth method. The as-prepared nanosheet HZSM-5 film exhibits reaction rate enhancement up to 312% in catalytic cracking of n-dodecane as well as twice light olefins selectivity, ascribed to the better mass transfer of reactants in the hierarchical porous structure and the ultra-thin b-axis pores of nanosheets. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-14T11:06:16.325701-05:
      DOI: 10.1002/aic.16158
  • Liquid-to-solid ratio control as an advanced process control solution for
           continuous twin-screw wet granulation
    • Authors: Niels Nicolaï; Fien De Leersnyder, Dana Copot, Michiel Stock, Clara M. Ionescu, Krist V. Gernaey, Ingmar Nopens, Thomas De Beer
      Abstract: Assuring compliance of intermediate and final quality attributes in a continuous pharmaceutical manufacturing campaign is of utmost importance. Application of corrective actions might be required in real-time. This work exemplifies the steps needed to identify a linear pulse transfer function for the dynamic behaviour of the granule liquid-to-solid ratio (%w/w) at the end of the granulation unit of a commercial ConsiGmaTM-25 production line. Near-infrared spectroscopy was used to monitor the granule composition in-line. The outcome for both the tracking and regulator problem using either conventional or model predictive control was implemented and evaluated. Dynamic setpoints were correctly followed and an RMSE of 0.25%w/w with respect to the setpoint was obtained when inducing artificial disturbances. Important practical challenges were also tackled. Examples are fouling, computational limitations and the limited flexibility of the automation software. Applying the proposed advanced process control solution offers an answer to upstream material flow rate deviations. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-14T11:05:45.006963-05:
      DOI: 10.1002/aic.16161
  • Direct Numerical Simulation of Surfactant Solution Flow in the Wide-Rib
           Rectangular Grooved Channel
    • Authors: Chonghai Huang; Dongjie Liu, Jinjia Wei, Bo Yu, Hongna Zhang, Jianping Cheng
      Abstract: The turbulent flow of surfactant solution in the wide-rib rectangular grooved channels was studied by direct numerical simulation. Moreover, the variations of near-wall streamwise vortices with time were discussed and the distributions of streamwise vortex radius, swirling strength and density were quantitatively investigated. It was found that the influence of microgrooves on the fluid mainly occurred within the buffer layer and microgrooves could induce numerous streamwise vortices with small size and swirling strength within the grooved valleys. The drag-reducing enhancement mechanism of microgroove in the surfactant solution could be mainly considered as the competing results between the “restriction effect” and “tip effect” of microgroove, and the essential factor should be the numerous secondary streamwise vortices with small size and swirling strength within the grooved valleys. Furthermore, a predicted method for the optimal drag-reducing size of microgroove was proposed, and the prediction values agreed well with the numerical results. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-14T11:05:41.641361-05:
      DOI: 10.1002/aic.16156
  • Nano-Engineered Nickel Catalysts Supported on 4-Channel α-Al2O3 Hollow
           Fibers for Dry Reforming of Methane
    • Authors: Zeyu Shang; Shiguang Li, Qingfa Wang, Xuehong Gu, Xinhua Liang
      Abstract: A nickel (Ni) nanoparticle catalyst, supported on 4-channel α-Al2O3 hollow fibers, was synthesized by atomic layer deposition (ALD). Highly-dispersed Ni nanoparticles were successfully deposited on the outside surfaces and the inside porous structures of hollow fibers. The catalyst was employed to catalyze the dry reforming of methane (DRM) reaction and showed a methane reforming rate of 2040 Lh−1gNi−1 at 800°C. NiAl2O4 spinel was formed when Ni nanoparticles were deposited on alpha-alumina substrates by ALD, which enhanced the Ni-support interaction. Different cycles (two, five, and ten) of Al2O3 ALD films were applied on the Ni/hollow fiber catalysts to further improve the interaction between the Ni nanoparticles and the hollow fiber support. Both the catalyst activity and stability were improved with the deposition of Al2O3 ALD films. Among the Al2O3 ALD coated catalysts, the catalyst with five cycles of Al2O3 ALD showed the best performance. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-14T11:02:07.85122-05:0
      DOI: 10.1002/aic.16160
  • The Trail of Perfumes
    • Authors: Joana Pereira; Patrícia Costa, Maria C. Coimbra, Alírio E. Rodrigues
      Abstract: A methodology is proposed for modeling the diffusion of fragrances released from a moving source. First, we started with a 1D model considering molecular diffusion of α-pinene in air as the only mass transport mechanism. The validation was performed in a diffusion tube, and a system was developed to move the scented source along the axial direction. Results showed that experimental data fitted well with the numerical simulation, suggesting this model as a valid tool to describe the trail of a fragrance released from a moving source for low Re of the order of 10. In the case of a person walking at the speed of 1.34 m/s in a room or corridor inside a building, 3D models are required and mass transport of the perfume to the surrounding air will be dominated by turbulent diffusion or eddy diffusion Dt which is two orders of magnitude higher than molecular diffusion. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-12T12:55:52.130338-05:
      DOI: 10.1002/aic.16155
  • Chemical Engineering and the Culmination of Quality by Design in
    • Authors: Paul C. Collins
      PubDate: 2018-03-12T12:50:22.060605-05:
      DOI: 10.1002/aic.16154
  • Product Design: A Pricing Framework Accounting for Product Quality and
           Consumer Awareness
    • Authors: Yuk C. Chan; Ka Y. Fung, Ka M. Ng
      Abstract: A systematic framework has been developed to determine the optimal price of a completely new (or existing but improved) chemical product that is being launched (or re-launched) in the presence of a competing product. It has four elements. The first is a pricing model derived from a utility function with constant elasticity of substitution. It accounts for consumers' awareness of the product under consideration and consumer preferences. The second is a set of relationships relating the consumer preferences and the relevant sales data available to a re-launched product to the parameters of the pricing model. In the absence of sales data for a completely new product, the third element is a set of heuristics for choosing a pricing strategy and estimates of the pricing model parameters. The optimal price is finally determined in a profit maximization problem subject to the market size as well as any other constraints. This pricing framework allows simultaneous optimization of product quality and price using product specifications as design variables. It is illustrated with an example on energy drinks. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-06T18:00:22.894195-05:
      DOI: 10.1002/aic.16153
  • Learning from the Past: Are Catalyst Design Principles Transferrable
           between Hydrodesulfurization and Deoxygenation'
    • Authors: Sashank Kasiraju; Lars C. Grabow
      Abstract: Molybdenum-oxide (MoO3) is a promising catalyst candidate for hydrodeoxygenation (HDO) of pyrolysis vapor or liquefaction products to renewable fuels or value-added chemicals. We used density functional theory to study the mechanism and active site requirements for HDO of furan over the MoO3(010) facet and contrast our results with prior work on hydrodesulfurization (HDS) of thiophene over MoO2 model catalysts. The potential energy diagram for HDO over a realistically terminated MoO3(010) surface facet reveals that the elementary reaction steps for deoxygenation are facile, but the formation of oxygen-vacancies is slow and endothermic. In general, HDO over MoO3 and HDS over MoS2 exhibit mechanistic similarities, which suggests that knowledge transfer from the mature HDS system to the emerging field of HDO catalysis is possible. For example, transition metal promotion of MoO3 resulted in an improvement in the kinetics and thermodynamics of oxygen vacancy formation, similar to Co and Ni promotion of MoS2. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-03T11:15:25.35817-05:0
      DOI: 10.1002/aic.16151
  • Analysis of Volume-to-Surface Ratio Effects on Methane Oxidative Coupling
           using Microkinetic Modeling
    • Authors: V.I. Alexiadis; T. Serres, G.B. Marin, C. Mirodatos, J.W. Thybaut, Y. Schuurman
      Abstract: The effect of the Volume-to-Surface (V/S) ratio on the catalytic performance of a La-Sr/CaO catalyst in a fixed bed reactor under oxidative coupling of methane (OCM) conditions is investigated by adjusting the amount of diluent in the catalyst bed. It was observed experimentally that the catalyst activity, C2 selectivity and C2H4/C2H6 ratio are all favored at high V/S ratios. The total void volume, available in the intraparticle and the interstitial phase, was considered. A comprehensive OCM microkinetic model, explicitly distinguishing between these two phases, allowed accounting for the observed dependence of catalytic performance on V/S ratio. The major experimentally implemented variation in interstitial volume available for reaction, provoked also changes in radical concentration profiles in intraparticle phase. Given the high reaction rates occurring at this location, the experimentally observed effects with varying the V/S ratio, are attributed to concentration and, hence, reaction rate changes occurring mainly in the intraparticle phase. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-03T11:10:30.326261-05:
      DOI: 10.1002/aic.16152
  • Issue Information
    • Abstract: Cover illustration. Additive manufacturing offers the capability to build reactors and components with complex geometries and topologies previously unaccessible to the reactor design engineer. These capabilities could allow a transition from site-built facilities [left, courtesy of Matt Jiggins,] to optimized additively manufactured designs [right, examples of metal objects built using Direct Metal Laser Sintering (DMLS) courtesy of Oakridge National Laboratory,]. 10.1002/aic.16118
      PubDate: 2018-03-02T11:07:53.504782-05:
      DOI: 10.1002/aic.15902
  • Effect of Peptide Linker Length and Composition on Immobilization and
           Catalysis of Leucine Zipper-Enzyme Fusion Proteins
    • Authors: Adam A. Caparco; Andreas S. Bommarius, Julie A. Champion
      Abstract: Linkers are critical components of fusion proteins, as they physically separate individual domains to enable each to fold and retain function. The role of peptide linker properties was investigated for fusions of a leucine zipper immobilization domain (ZE) to a chimeric amine dehydrogenase (AmDH) or a formate dehydrogenase (cbFDH). A linker library was developed, which varied in length, orientation, and proline content, as a way to vary stiffness. Fusion proteins were characterized by melting temperature, immobilization ability, cofactor binding, and kinetic activity. The best linker candidate for each enzyme was tested in a dual-functionality assay, where enzymatic activity of fusions immobilized in protein-inorganic supraparticles was greater than 80% after washing. The best linker for AmDH was completely different than that for cbFDH. This work highlights the need to experimentally assess linker properties in the design of new fusion proteins and provides a linker library for this purpose. This article is protected by copyright. All rights reserved.
      PubDate: 2018-03-01T11:30:30.485719-05:
      DOI: 10.1002/aic.16150
  • Multi-Actor Multi-Criteria Decision Making for Life Cycle Sustainability
           Assessment under Uncertainties
    • Authors: Jingzheng Ren; Xusheng Ren, Lichun Dong, Alessandro Manzardo, Chang He, Ming Pan
      Abstract: This paper aims at developing a generic multi-actor multi-criteria decision making (MAMCDM) method for life cycle sustainability assessment (LCSA) of industrial systems under uncertainties, which can help multiple stakeholders/decision-makers to prioritize the alternative industrial systems in a group decision-making approach. The interval best-worst method, which can address the ambiguity, vagueness and hesitations existing in human's judgments, was developed for determining the weight of the criteria in LCSA. The consensus convergence model was developed for aggregating the relative importance of each criterion determined by different stakeholders/decision-makers into an interval weight. Afterwards, a novel multi-criteria decision making method which can address the decision-making matrix with interval numbers was developed to prioritize industrial systems under data uncertainties. An illustrative case has been studied by the developed model, and it reveals that the developed model allows multiple stakeholders/decision-makers to participate in the decision-making processes and prioritize industrial systems accurately by using interval numbers. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-27T17:55:41.903391-05:
      DOI: 10.1002/aic.16149
  • Measurements of Horizontal Three-Phase Solid-Liquid-Gas Slug Flow:
           Influence of Hydrate-Like Particles on Hydrodynamics
    • Authors: Luis M.M. Rosas; Carlos L. Bassani, Rafael F. Alves, Fábio A. Schneider, Moisés A. Marcelino Neto, Rigoberto E.M. Morales, Amadeu K. Sum
      Abstract: Gas hydrate formation is a main flow assurance concern in oil and gas production. Understanding the effects of the introduction of solid particles in the slug flow is essential to improve the efficiency and safety of multiphase production. The purpose of the present work is the experimental characterization of solid-liquid-gas slug flow with the presence of dispersed hydrate-like particles. Experimental tests were carried out with inert polyethylene particles of 0.5-mm diameter with density similar to gas hydrates (938 kg/m3). The test section comprised a 26-mm ID, 9-m length horizontal duct of transparent Plexiglas. High Speed Imaging and resistivity sensors was used to analyze the slug flow unit cell behavior due to the introduction of the solid particles and to measure the unit cell translational velocity, the slug flow frequency, the bubble and slug lengths, and the phase fractions. Two distinct concentrations of solid particles were tested (6 and 8 g/dm3). This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-27T17:55:39.422906-05:
      DOI: 10.1002/aic.16148
  • Acid Hydrolysis of Glycosidic Bonds in Oat β-glucan and Development of a
           Structured Kinetic Model
    • Authors: Hoang S. H. Nguyen; Jari Heinonen, Tuomo Sainio
      Abstract: Homogeneous acid-catalyzed hydrolysis of oat β-glucan, which contains β-(1,4) and β-(1,3) glycosidic bonds in a nonrandom order, was studied at 353 K using HCl and H2SO4. A new structured kinetic model was developed that takes into account the difference in the reactivity of β-(1,4) and β-(1,3) glycosidic bonds as well as their positions in the polysaccharide chain. In order to minimize the correlation of adjustable parameters in the new model, the reactivities of these bonds were studied independently (T = 313…363 K; cH+ = 0.1…2 mol/L) using cellobiose and laminaribiose. The difference in kinetic parameters (e.g. T = 338 K: kβ-(1,4) = 0.693 × 10−3 L/mol/min, kβ-(1,3) = 1.027 × 10−3 L/mol/min) was found to be statistically significant (P 
      PubDate: 2018-02-27T17:55:30.571479-05:
      DOI: 10.1002/aic.16147
  • A Hybrid Thermo-Kinetic Model for High Temperature Plasma Gasification
    • Authors: Babita K. Verma; E. Rajeshkannan, T. Renganathan, S. Pushpavanam
      Abstract: Plasma gasification is a process intensification technique in which the prevailing high temperatures accelerate the reactions resulting in a significant size reduction of the gasifier. Conventionally, a gasifier is modeled using either a thermodynamic or a kinetic approach. Present work proposes a novel method of modeling the plasma gasification process which combines these two approaches. The process is modelled as a combination of two regions: a Plasma Gasifier Zone (PGZ) and a Quenching Zone (QZ). PGZ, where gasification of feedstock takes place at high temperatures is modeled by thermodynamic equilibrium. QZ, where the syngas produced in the PGZ cools down, is modeled by kinetic approach. The hybrid approach captures the behavior more accurately and requires less computational effort. The proposed hybrid model is validated with experimental data from literature. The model is used to analyze the influence of radicals in plasma gasification and the performance for different operating conditions. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-27T17:55:28.120298-05:
      DOI: 10.1002/aic.16146
  • Validation study on spatially averaged two-fluid model for gas-solid
           flows: I. A-priori analysis of wall bounded flows
    • Authors: Simon Schneiderbauer
      Abstract: In our prior study (Schneiderbauer, AIChE J., 2017;63(8):3544–3562), we presented a spatially averaged two-fluid model (SA-TFM), where closure models for the unresolved terms were derived. These closures require constitutive relations for the turbulent kinetic energies (TKE) of the gas and solids phase as well as for the sub-filter variance of the solids volume fraction (VVF). In the present study, we have performed highly resolved TFM simulations of a set of three-dimensional wall dominated periodic channels. An a-priori analysis shows that these closures are able to correctly predict the wall profiles of the sub-grid drag modification, the TKEs, the turbulent viscosities and the VVF without requiring special wall corrections. Solely the mixing lengths, which is required by the closures, has to be adapted in the vicinity of wall similar to single-phase turbulence; in particular, the minimum of the filter size and the distance to the wall should be used. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-26T11:31:19.904152-05:
      DOI: 10.1002/aic.16142
  • Validation study on spatially averaged two-fluid model for gas-solid
           flows: II. Application to risers and fluidized beds
    • Authors: Simon Schneiderbauer
      Abstract: In our prior study (Schneiderbauer, AIChE J., 2017;63(8):3544–3562), we presented a spatially averaged two-fluid model (SA-TFM), where closure models for the unresolved terms were derived. These closures require constitutive relations for the turbulent kinetic energies of the gas and solids phase as well as for the sub-filter variance of the solids volume fraction. We had ascertained that the filtered model do yield nearly the same time-averaged macro-scale flow behavior in bubbling fluidized beds as the underlying kinetic-theory-based two-fluid model (TFM), thus verifying the SA-TFM model approach. In the present study, we have performed a set of 3D computational simulations for validation of the SA-TFM against the experimental data on riser flow and bubbling fluidized beds. Finally, the SA-TFM predictions are in fairly good agreement with experimental data in the case of Geldart A and B particles even though using very coarse grids. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-26T11:30:26.82155-05:0
      DOI: 10.1002/aic.16141
  • Application of Inline Imaging for Monitoring Crystallization Process in a
           Continuous Oscillatory Baffled Crystallizer (COBC)
    • Authors: Rohit Kacker; Sebastian Maaß, Jörn Emmerich, Herman Kramer
      Abstract: In this study, an in-situ imaging system has been analysed to characterize the crystal size, the shape and the number of particles during a continuous crystallization process in a COBC. Two image analysis approaches were examined for particle characterization in the suspension containing both small nuclei and larger grown crystals (non-spherical and irregular in shape). The pattern matching approach, in which the particles are approximated to be spherical, did result in an overestimation of the size. Alternatively, a segmentation based algorithm resulted in reliable crystal size and shape characteristics. The laser diffraction analysis in comparison to the image analysis overestimated the particle sizes due to the agglomeration of particles upon filtration and drying. The trend in the particle counts during the start of crystallization process, including nucleation, determined by the image analysis probe was comparable with the one measured by FBRM, highlighting the potential of in-situ imaging for process monitoring. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-26T11:25:24.758984-05:
      DOI: 10.1002/aic.16145
  • Modeling of Hydrogen Separation through Porous YSZ Hollow Fiber-supported
           Graphene Oxide Membrane
    • Authors: Yun Jin; Xiuxia Meng, Naitao Yang, Bo Meng, Jaka Sunarso, Shaomin Liu
      Abstract: In this work, hydrogen (H2) permeation fluxes through 230 nm-thick graphene oxide (GO) membrane deposited on porous YSZ hollow fiber were measured and correlated to an explicit H2 permeation model. H2 fluxes through such GO-YSZ hollow fiber membrane increased from 4.83 × 10−8 mol cm−2 s−1 to 2.11 × 10−7 mol cm−2 s−1 with temperature rise from 20°C to 100°C. The activation energy of H2 permeation was determined by the linear regression of the experimental data and was applied in the theoretical calculations. The model predictions fit well the temperature dependent and the argon sweep gas flow rate dependent H2 fluxes data. Using the derived permeation model, the effects of vacuum pressure at lumen side and H2 partial pressure at shell side, membrane area, and GO membrane film thickness on the membrane performance were simulated and discussed to provide insights for practical applications. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-24T12:16:40.143023-05:
      DOI: 10.1002/aic.16144
  • New Algorithm for the Flexibility Index Problem of Quadratic Systems
    • Authors: Hao Jiang; Bingzhen Chen, Ignacio E. Grossmann
      Abstract: A new flexibility index algorithm for systems under uncertainty and represented by quadratic inequalities is presented. Inspired by the outer-approximation algorithm for convex mixed-integer nonlinear programming, a similar iterative strategy is developed. The subproblem, which is a nonlinear program, is constructed by fixing the vertex directions since this class of systems is proved to have a vertex solution if the entries on the diagonal of the Hessian matrix are non-negative. By overestimating the nonlinear constraints, a linear min-max problem is formulated. By dualizing the inner maximization problem, and introducing new variables and constraints, the master problem is reformulated as a mixed-integer linear program. By iteratively solving the subproblem and master problem, the algorithm can be guaranteed to converge to the flexibility index. Numerical examples including a heat exchanger network, a process network, and a unit commitment problem are presented to illustrate the computational efficiency of the algorithm. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-24T12:10:26.845743-05:
      DOI: 10.1002/aic.16143
  • Velocity Variation Effect in Fixed Bed Columns: A Case Study of CO2
           Capture using Porous Solid Adsorbents
    • Authors: Nadeen Al-Janabi; Reza Vakili, Patthadon Kalumpasut, Patricia Gorgojo, Flor R. Siperstein, Xiaolei Fan, Paschal McCloskey
      Abstract: This study shows that for a reliable evaluation of porous adsorbents for carbon capture based on the fixed bed adsorption analysis, one must consider the effect of velocity variation due to adsorption to make a fair judgment on predicting the performance of materials under flow conditions. A combined experimental and numerical study of CO2/N2 adsorption in fixed beds using three forms of adsorbents of amorphous powder (bulk activated carbon), crystalline powder (bulk Cu-BTC metal-organic framework, MOF) and crystalline pellets (pelleted Cu-BTC) was carried out to show the effect of velocity variation on CO2 breakthrough curves. Significant deviations are observed in the estimated amount adsorbed calculated from fixed bed experiments when models used for interpretation the measured data consider constant gas velocity because the stoichiometric time is underestimated. We show that the difference in breakthrough times estimated in models that consider constant and variable gas velocity grows exponentially with the feed gas concentration. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-23T11:40:35.71837-05:0
      DOI: 10.1002/aic.16135
  • How the Catalyst Circulates and Works in Organocatalyzed Atom Transfer
           Radical Polymerization
    • Authors: Jun-Kang Guo; Luo Zheng-Hong
      Abstract: The catalyst plays a vital role in organocatalyzed atom transfer radical polymerization (O-ATRP). Catalysts in the ground-state, excited-state and oxidized-state are in competitive equilibrium and mutually transforming status. However, the catalyst circulation process remains unclear in some respects. In this work, for the first time, a novel kinetic model is successfully developed to illustrate the exact circulation process and working mechanism of catalyst. For a broad range of conditions, the reported model presents excellent descriptions of kinetic behaviors of O-ATRP. In the polymerization process, the photolysis effect contributes to a small proportion of radical generation. Sufficient deactivation effect is crucial for controlled polymerization at the early stage of polymerization. And increased light intensity, halide ion concentration, catalyst loading and initiator concentration accelerate the establishment of catalyst dynamic equilibrium. Additionally, the excited-state catalyst quenches with an extremely high rate, leading to an immediate dormant period in “on–off” light switching regulation. The formulated results shed light on the catalyst circulation process and provide insights into the polymerization kinetics. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-23T11:40:32.183073-05:
      DOI: 10.1002/aic.16134
  • Quantified Mass Transfer and Superior Antiflooding Performance of Ordered
           Macro-Mesoporous Electrocatalysts
    • Authors: Min Jie Wang; Tao Zhao, Wei Luo, Zhan Xin Mao, Siguo Chen, Wei Ding, Yonghui Deng, Wei Li, Jing Li, Zidong Wei
      Abstract: For oxygen reduction reaction (ORR), constructing porous catalysts are highly important for mass transfer inside. However, the various porous structures usually possess significantly different water buffer efficiency, i.e. the antiflooding capability, for which one is still difficult to give a quantitative evaluation. In this work, we designed a special “rattle-drum” like working electrode, by which an exactly quantitative assessment on the mass transfer efficiencies can be conducted. Particularly, ordered macro-mesoporous Pt/C shows quantified mass transfer and antiflooding efficiency to be 4 times high as that of the commercial one. This observation should be attributed to their different pore characteristics, as the dual-porosity Pt/C has 3.4 times the pore volume of the commercial one, together with regular pore arrangement. Simultaneously, it also demonstrated excellent durability, indicating that the macro-mesoporous Pt/C indeed owns high stability in both antiflooding and durability. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-23T11:35:52.192026-05:
      DOI: 10.1002/aic.16140
  • The Role of Wettability of Non-ideal Nozzle Plate: from Drop-on-Demand
           Droplet Jetting to Impact on Solid Substrate
    • Authors: Lei Zhang; Tao Ku, Xiaoding Cheng, Jingsong Jia
      Abstract: The dynamics of drop-on-demand (DoD) droplet formation and subsequently impact on the solid substrate are investigated using a three-dimensional (3D) multi-relaxation-time (MRT) pseudopotential lattice Boltzmann (LB) model. The wettability of non-ideal nozzle plate and solid substrate is modelled by a geometric scheme within the LB framework. The dynamics of droplet formation are explored in a range of the inverse of Ohnesorge number Z = 4.95, 11.57 and 28.17, and the Reynolds number Re = 39.6, 58.9 and 136.4. For Z = 4.95, no satellite droplet is observed and the wettability of nozzle plate greatly influences the velocity and length of jetting fluids. For Z=11.57, the filament breakup and recombination are observed. The moment of filament breakup is delayed with advancing contact angle θA increasing. For Z = 28.17 with Re = 136.4, the primary and satellite droplets could not be recombined with θA = 30° and θA = 60° which agree with the literature. Whereas with θA = 90°, the recombination occurs. The dynamics of subsequent oscillating droplet impact on the substrate are similar to that of equilibrium droplet which could obtain high-resolution printed features. Consequently, considering θA = 90° with large Z and Re numbers, the printable range could be extended which could help increase the printing frequency and boost the production outputs of inkjet printing. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-23T11:35:46.118192-05:
      DOI: 10.1002/aic.16139
  • Fully-Resolved Simulations of Single Char Particle Combustion using a
           Ghost-Cell Immersed Boundary Method
    • Authors: Kun Luo; Chaoli Mao, Nils Erland L. Haugen, Jianren Fan, Zhenya Zhuang
      Abstract: A novel ghost-cell immersed boundary method for fully resolved simulation of char particle combustion has been developed. The boundary conditions at the solid particle surface, such as velocity, temperature, density and chemical species concentration, are well enforced through the present method. Two semi-global heterogeneous reactions and one homogeneous reaction are used to describe the chemical reactions in the domain, and the Stefan flow caused by the heterogeneous reactions is considered. A satisfactory agreement can be found between the present simulation results and experimental data in the literature. The method is then used to investigate the combustion property of a char particle and the interaction between CO2 gasification and O2 oxidation. Furthermore, combustion effect on the exchange of mass, momentum and energy between gas- and solid- phase is explored. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-23T11:35:42.973607-05:
      DOI: 10.1002/aic.16136
  • Recombinantly Expressed Gas Vesicles as Nanoscale Contrast Agents for
           Ultrasound and Hyperpolarized MRI
    • Authors: Arash Farhadi; Gabrielle Ho, Martin Kunth, Bill Ling, Anupama Lakshmanan, George Lu, Raymond W. Bourdeau, Leif Schröder, Mikhail G. Shapiro
      Abstract: Ultrasound and hyperpolarized magnetic resonance imaging enable the visualization of biological processes in deep tissues. However, few molecular contrast agents are available to connect these modalities to specific aspects of biological function. We recently discovered that a unique class of gas-filled protein nanostructures known as gas vesicles could serve as nanoscale molecular reporters for these modalities. However, the need to produce these nanostructures via expression in specialized cultures of cyanobacteria or haloarchaea limits their broader adoption by other laboratories and hinders genetic engineering of their properties. Here, we describe recombinant expression and purification of Bacillus megaterium gas vesicles using a common laboratory strain of Escherichia coli, and characterize the physical, acoustic and magnetic resonance properties of these nanostructures. Recombinantly expressed gas vesicles produce ultrasound and hyperpolarized 129Xe MRI contrast at sub-nanomolar concentrations, thus validating a simple platform for their production and engineering. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-23T11:35:38.28603-05:0
      DOI: 10.1002/aic.16138
  • Carbon Dioxide Chemical Absorption by Solvents Based on Diamine and Amines
    • Authors: Alberto Cachaza; Diego Gómez-Díaz, Adrián Montáns, José M. Navaza, Antonio Rumbo
      Abstract: Present work includes research about the influence of the type of amino group using one or two amine molecules upon carbon dioxide chemical absorption by using aqueous solutions of alkanolamines and diamines. A comparison of chemical absorption processes using aqueous solutions of two individual diamines (3-(dimethylamino)propan-1-amine and 1,3-diaminopropane) and a mixture of amines (3-amino-1-propanol and 3-(dimethylamino)propan-1-ol) is reported including absorption rate curves, carbon dioxide loading, reaction mechanism or solvent regeneration to obtain useful information about the quality of each solvent for carbon dioxide separation. In general, amines blends of 3-amino-1-propanol and 3-dimethylamino-1-propanol, have shown a better behavior than their individual amines. Diamines and mainly 3-dimethylamino propylamine, that presents primary and tertiary amine groups in its structure, have led similar results. After these studies, 3-dimethylamino propylamine, can be considered an appropriated amine to industrial carbon dioxide absorption process. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-23T11:35:20.510377-05:
      DOI: 10.1002/aic.16137
  • Probabilistic Design Space determination in Pharmaceutical Product
           Development: a Bayesian/Latent Variable Approach
    • Authors: Gabriele Bano; Pierantonio Facco, Fabrizio Bezzo, Massimiliano Barolo
      Abstract: To find the design space (DS) of a pharmaceutical process, quantification of the “assurance of quality” for the product under development is required. In this study, latent-variable modeling is combined with multivariate Bayesian regression to identify a subset of input combinations (process operating conditions and raw materials properties) within which the DS of the product will lie at a probability equal to, or greater than, an assigned threshold. Partial least-squares regression is used to obtain a linear transformation between the original multidimensional input space and a low-dimensional latent space. The input domain is then discretized on its lower dimensional representation and a Bayesian posterior predictive approach is used to quantify the probability that the critical quality attributes of the product will meet their specifications for each discretization point. The methodology is tested on two case studies taken from the literature, one of which involving experimental data. The ability of the proposed approach to obtain a probabilistic identification of the DS, while simultaneously reducing the computational burden for the discretization of the input domain and providing a simple graphical representation of the DS, is shown. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-21T17:50:28.821898-05:
      DOI: 10.1002/aic.16133
  • The Effect of Particle Rotation on the Motion and Rejection of Capsular
           Particles in Slit Pores
    • Authors: Armin Delavari; Basavaraju Agasanapura, Ruth E. Baltus
      Abstract: In this paper, we report the results from a 2D computational model describing the motion of capsule shaped particles in a slit pore under small Re conditions. Average particle velocities and particle rejection coefficients were determined for capsules with aspect ratios of 2 and 4. Two different approaches were used to characterize particle rotation and hydrodynamic particle-pore wall interactions. In one approach, all sterically allowed particle orientation angles had equal probability, i.e., infinite rotational diffusion was assumed. In the second approach, particles were allowed to freely rotate in the pore; particle orientations were dictated by hydrodynamic forces acting on the particle surface and rotational particle diffusion was neglected. Minimal lateral migration across the pore was observed for the freely rotating particles. Although particle alignment was observed for the freely rotating particles, rejections predicted from the two approaches were found to be in close agreement. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-19T11:02:16.036915-05:
      DOI: 10.1002/aic.16132
  • An Experimental and Modeling Study of Vacuum Residue Upgrading in
           Supercritical Water
    • Authors: Soumya Gudiyella; Lawrence Lai, Isaiah H. Borne, Geoffrey A. Tompsett, Michael T. Timko, Ki-Hyouk Choi, Mohnnad H. Alabsi, William H. Green
      Abstract: Arabian Heavy crude oil was fractionated into distillate and vacuum residue fractions. The vacuum residue fraction was treated with supercritical water (SCW) at 450°C in a batch reactor for 15 to 90 minutes. The main products were gas, coke, and upgraded vacuum residue; the upgraded residue consisted of gasoline, diesel, and vacuum gas oil range components. The molecular composition of gas and upgraded vacuum residue was analyzed using gas chromatography (GC, GC×GC). SCW treatment converted higher carbon number aliphatics (≥ C21) and long chain (≥ C5) alkyl aromatic compounds into C1-C20 aliphatics, C1-C10 alkylaromatics and multi-ringed species. The concentrations of gasoline and diesel range compounds were greater in the upgraded product, compared to the feed. A first-order, five lump reaction network was developed to fit the yields of gas, coke, diesel and gasoline range components obtained from SCW upgrading of vacuum residue. Distillation of crude oil followed by SCW treatment of the heavy fraction approximately doubled the yield of chemicals, gasoline, and diesel, while forming significantly less coke than conventional upgrading methods. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-16T07:40:30.58323-05:0
      DOI: 10.1002/aic.16131
  • Hydrodynamics in a Pilot-Scale Cocurrent Trickle-Bed Reactor at Low Gas
    • Authors: Puneet Kawatra; Srikanth Panyaram, Benjamin A. Wilhite
      Abstract: Hydrodynamic data obtained from laboratory-scale trickle-beds often fail to accurately represent industrial-scale systems with high packing aspect ratios and column-to-particle diameter ratios. In this study, pressure drop, liquid holdup, and flow regime transition were investigated in a pilot-scale trickle-bed column of 33 cm ID and 2.45 m bed height packed with 1.6mm x 8.4 +/- 1.4mm cylindrical extrudates for air-water mass superficial velocities of 0.0023 - .094 kg/m2s and 4.5 – 45 kg/m2s, respectively, at atmospheric pressure. Significant deviation was observed from pressure drop and liquid holdup correlations at low liquid flows rates, corresponding to gravity-driven flow limit. Likewise, liquid saturation is overestimated by correlations at high liquid flowrates, owing to significantly reduced wall effects. Lastly, trickle-to-dispersed bubble flow and trickle-to-pulsing flow regime transitions are reported using a combination of visual observations and analysis of the magnitude of local pressure fluctuations within the column. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-14T13:19:26.260602-05:
      DOI: 10.1002/aic.16126
  • Experimental Data for Code Validation: Horizontal Air Jets in a
           Semicircular Fluidized Bed of Geldart Group D Particles
    • Authors: William D. Fullmer; Casey Q. LaMarche, Allan Issangya, Peiyuan Liu, Ray Cocco, Christine M. Hrenya
      Abstract: Experiments were conducted with 6 mm plastic beads (Geldart Group D) in a semi-circular, gas-fluidized bed with side jets. Attention was paid to particle characterization and bed measurements, making the resulting dataset ideal for CFD-DEM validation and uncertainty quantification. The bed was operated slightly above and below the minimum fluidization velocity, with additional fluidization provided by one of two pairs of opposing jets located above the distributor near the flat, front face of the unit. Care is taken to report material properties and bed conditions with either measured distribution functions or uncertainty bounds. High-speed video imaging and particle tracking velocimetry are used to extract bin-averaged velocity profiles, which are used to extract jet penetration depths. The time-averaged mean and standard deviation of the bed pressure drop is also reported. Finally, the lower jets are also inserted into the bed until the opposing jets merge to form a spout-like pattern. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-14T11:40:50.212041-05:
      DOI: 10.1002/aic.16128
  • Framework for Work-Heat Exchange Network Synthesis (WHENS)
    • Authors: Sajitha K Nair; Harsha Nagesh Rao, I A Karimi
      Abstract: Work and heat are the two predominant forms of energy in the process industry. Considerable savings can be achieved by synergizing the work and heat requirements of process streams. In this work, a generalized framework for integrating heat and work simultaneously is proposed based on a mixed-integer nonlinear programming (MINLP) model for work-heat exchange network synthesis (WHENS). Starting with a set of streams with known flows, temperatures, and pressures, a network of single-shaft-turbine-compressors (SSTCs) with motors/generators, valves, heat exchangers, and utility heaters/coolers is synthesized for minimized total annualized cost. In contrast to existing works, we (1) do not pre-classify streams as hot/cold or high/low-pressure, (2) allow pressure changes for streams with no net pressure change, (3) allow liquid-vapor phase changes, and (4) use phase-based property correlations. Successful application of our approach to C3 splitting yields a non-intuitive configuration. We also study another application of an offshore natural gas liquefaction process. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-14T11:40:36.128707-05:
      DOI: 10.1002/aic.16129
  • Relative time-averaged gain array (RTAGA) for distributed control-oriented
           network decomposition
    • Authors: Wentao Tang; Davood Babaei Pourkargar, Prodromos Daoutidis
      Abstract: Input-output partitioning for decentralized control has been studied extensively using various methods, including those based on relative gains and those based on relative degrees and sensitivities. These two concepts are characterizations of long-time and short-time input-output response, respectively. This work proposes a unifying new input-output interaction measure, called relative time-averaged gain, which characterizes the input-output interactions during a time scale of interest for linear time-invariant systems. This measure is used as a basis for community detection in the input-output bipartite graph of a process network to produce subnetworks whose responses are weakly coupled in the time scale of interest. As such, the resulting decomposition accounts for both response characteristics and the network topology, and can be used efficiently for distributed control architecture design. In a case study, the proposed decomposition is applied to the distributed model predictive control of a reactor-separator benchmark process. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-14T11:40:22.836026-05:
      DOI: 10.1002/aic.16130
  • Experimental and numerical investigation of structure and hydrodynamics in
           packed beds of spherical particles
    • Authors: P. Lovreglio; S. Das, K.A. Buist, E.A.J.F. Peters, L. Pel, J.A.M. Kuipers
      Abstract: In chemical industry, flows often occur in non-transparent equipment, for example in steel pipelines and vessels. MRI is a suitable approach to visualize the flow, which cannot be performed with classical optical techniques, and obtain quantitative data in such cases. It is therefore a unique tool to non-invasively study whole-field porosity and velocity distributions in opaque single-phase porous media flow. In this paper, experimental results obtained with this technique, applied to the study of structure and hydrodynamics in packed beds of spherical particles, are shown and compared with detailed CFD simulations performed with an in-house numerical code based on an IBM-DNS approach. Pressure drop and the radial profiles of porosity and axial velocity of the fluid for three packed beds of spheres with different sizes were evaluated, both experimentally and numerically, in order to compare the two approaches. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-14T11:35:47.018689-05:
      DOI: 10.1002/aic.16127
  • Continuous Manufacturing: Is the Process Mean Stationary'
    • Authors: Levente L. Simon
      Abstract: This paper describes the statistical framework to systematically detect mean stationarity in the context of continuous manufacturing. The methods presented in this paper use econometric and financial time-series analysis concepts in the form of unit-root and stationarity hypothesis tests. The tests under discussion are the augmented Dickey-Fuller, Philips-Perron, Leybourne-McCabe and Kwiatkowski-Phillips-Schmidt-Shin. These hypothesis tests are evaluated on data generated by a focused-beam reflectance measurement sensor implemented on-line in a continuous plug-flow crystallizer.This contribution has shown that the hypothesis tests can be used to detect steady-state conditions on-line in a plug-flow crystallizer. Furthermore, this econometric framework can be used as a mean stationarity “certificate” of collected samples to document that the process was mean stationary during the sampling.The statistical framework described in this paper can be applied to any continuously operated unit operation or sensor measurement. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-14T11:30:24.719796-05:
      DOI: 10.1002/aic.16125
  • Heat/Mass Transfer from a Neutrally Buoyant Sphere by Mixed Natural and
           Forced Convection in a Simple Shear Flow
    • Authors: Bing Yuan; Chao Yang, Zai-Sha Mao, Xiaolong Yin, Donald L. Koch
      Abstract: Building on the work of Yang et al. in 2011, the finite difference method and the Boussinesq approximation were applied to solve the time-dependent Navier-Stokes, convection diffusion and continuity equations in spherical coordinates. An idealized condition, the mass transfer from a neutrally buoyant sphere in a horizontal simple shear flow with natural convection was numerically simulated for the first time in this work. In the hybrid transfer case, the outwardly spiraling streamlines enhanced the transfer process, but the counter-gravity spiraling streamlines near the sphere hindered the natural convection and the spatial dilution action weakened the natural convection transfer process. These competing effects led to non-monotonic behavior of the Nusselt number with Reynolds number. Results from these previously undocumented cases were summarized into correlations for predicting Nusselt numbers at finite Reynolds numbers for various Grashof and Prandtl numbers. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-12T07:40:32.71646-05:0
      DOI: 10.1002/aic.16122
  • Concentrated Slurry Formation via Drawdown and Incorporation of Wettable
           Solids in a Mechanically Agitated Vessel
    • Authors: Thomas Wood; Mark J. H. Simmons, Richard W. Greenwood, E. Hugh Stitt
      Abstract: This paper describes the effect of vessel configurations upon the drawdown and incorporation of floating solids to prepare concentrated alumina slurries in stirred tanks. The impeller speed and power draw required to incorporate all dry powder within four seconds, NJI and PJI, are used to evaluate incorporation performance. The effect of impeller type is assessed, with pitched blade impellers proving to be the most effective across the full range of solid contents considered.At higher solids content the energy demand is shown to increase dramatically, with a 100-fold increase in energy required to add 1% w/w more solid at 50% by weight compared to 1% by weight. Analysis of impeller power numbers show this coincides with a transition from constant power number to a region where power number increases linearly with decreasing Reynolds number. Contrary to studies at low solids content, the presence of baffles is shown to inhibit drawdown. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-12T07:40:22.789403-05:
      DOI: 10.1002/aic.16121
  • Theoretical and Computational Comparison of Continuous-Time Process
           Scheduling Models for Adjustable Robust Optimization
    • Authors: Nikolaos H. Lappas; Chrysanthos E. Gounaris
      Abstract: Coping with uncertainty in system parameters is a prominent hurdle when scheduling multi-purpose batch plants. To that end, we previously introduced a multi-stage adjustable robust optimization framework that was shown to be able to obtain more profitable solutions, while maintaining the same level of immunity against risk, as compared to traditional robust optimization approaches. In this paper, we investigate the amenability of existing deterministic continuous-time scheduling models to serve as the basis of this adjustable robust optimization framework. We conduct a comprehensive computational study that compares the numerical tractability of various models across a suite of literature benchmark instances and a wide range of uncertainty sets. As part of this study, we also provide for the first time in the open literature robust optimal solutions to process scheduling instances involving uncertainty in production yields. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-12T07:31:07.982939-05:
      DOI: 10.1002/aic.16124
  • The impact of hydrodynamics on viscosity evolution in colloidal
           dispersions: Transient, nonlinear microrheology
    • Authors: Ritesh P. Mohanty; Roseanna N. Zia
      Abstract: Evolution of microstructure and rheology during flow startup, and its connection to microscopic transport processes, is studied theoretically via active microrheology. At steady state, the balance between entropic, hydrodynamic, and other forces changes with flow strength, producing sustained microstructural asymmetry and non-Newtonian rheology. However, the transition from equilibrium to steady flow is sometimes marked by overshoots in viscosity that suggests a temporally evolving competition between these rate processes. Here we formulate and solve a Smoluchowski equation for the time-dependent evolution of particle microstructure induced by the motion of a colloidal probe driven through a bath of colloidal spheres. The structure is then utilized to compute the time-dependent microviscosity. Brownian diffusion always sets short-time particle dynamics, which hinders maturation of the boundary layer. The disparity in Brownian and advective transport rates produces a reversal from flow thinning to flow thickening during startup, revealing that non-Newtonian flow phenomenology is not instantaneously established. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-12T07:25:28.274154-05:
      DOI: 10.1002/aic.16123
  • Reduction in Greenhouse Water usage through Inlet CO2 Enrichment
    • Authors: Neil Stacey; James Fox, Diane Hildebrandt
      Abstract: Agriculture is mankind's single largest usage of water, comprising 70% of all water usage. Optimizing water usage in agriculture is therefore crucial to ensuring global water security. In this paper, a greenhouse is quantitatively modelled as a bio-reactor and it is shown the bulk of the water supplied to a conventionally-aspirated greenhouse is lost in the form of humidity. This implies that evaporative losses in agriculture comprise a clear majority of mankind's total water consumption. This article demonstrates that inlet CO2 enrichment using existing membrane materials can minimize the air feed rate required to supply adequate CO2 for photosynthesis, thereby mitigating evaporative losses. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-07T18:40:31.829241-05:
      DOI: 10.1002/aic.16120
  • Manufactured Chemistry: Rethinking unit operation design in the age of
           additive manufacturing
    • Authors: Addison Killean Stark
      Abstract: Additive manufacturing enables new approaches to chemical reactor design due to the ability to build complex geometries and topologies unaccessible to traditional manufacturing technologies. These benefits have been demonstratedinthedesignandmanufactureofnovelheatexchangersandfluidicdevices. However,duetoprevailingheuristics in chemical reactor design, many of the benefits of additive manufacturing have yet to be realized by the chemical engineer. In order to reap these benefits, a formalized design methodology such as topology optimization should be employed for the development of high-efficiency small scale modular reactors capable of being manufactured at large volumes. In this way we may be able to start to descend fast manufacturing learning curves and unleash a new wave of innovation in the chemical engineering sciences. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-07T18:30:29.632699-05:
      DOI: 10.1002/aic.16118
  • Microfluidic Synthesis of Elastomeric Microparticles: A Case Study in
           Catalysis of Palladium-Mediated Cross-Coupling
    • Authors: Jeffrey Bennett; Andrew Kristof, Vishal Vasudevan, Jan Genzer, Jiri Srogl, Milad Abolhasani
      Abstract: Palladium (Pd)-loaded poly-hydromethylsiloxane (PHMS) microparticles of tunable size and elasticity are prepared in a capillary-based coaxial flow-focusing microfluidic device constructed using off-the-shelf components. Simultaneous droplet formation and chemical cross-linking processes are performed by tuning the dilution of the cross-linking catalyst in the annular flow of the microreactor, resulting in PHMS microparticles synthesized in a single step. The size of the elastomeric microparticles can be tuned by adjusting the flow rate ratio of the polymer and cross-linker mixture to water, while the elasticity can be tuned by the polymer to cross-linker ratio as well as the flow rate ratio of the polymer mixture to cross-linking catalyst mixture. Microparticle elasticity is characterized by the degree of solvent uptake. Application of the synthesized PHMS microparticles in organic synthesis is demonstrated by producing monodispersed Pd-loaded microparticles and utilizing them as microreaction vessels for continuous Suzuki-Miyaura cross-coupling in a Pd-loaded microparticle-packed bed reactor (µ-PBR). This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-07T18:26:23.902702-05:
      DOI: 10.1002/aic.16119
  • Hydrothermal Pretreatment for Deconstruction of Plant Cell Wall: Part I.
           Effect on Lignin-Carbohydrate Complex
    • Authors: Kun Yao; Qinfeng Wu, Ran An, Wei Meng, Mingzhu Ding, Bingzhi Li, Yingjin Yuan
      Abstract: Hydrothermal pretreatment with characteristic of green chemistry is considered as promising technology in the biorefineries. In this study, using material balance and multi-scale characterization techniques, the effects of process severity factor and pH on chemical behaviors of lignin-carbohydrate complex (LCC) were systematically studied. During pretreatment, spatial relocation of lignin with covalently linked xylan facilitated local cell wall collapse. A kinetic model was established to describe the behaviors of LCC components changing with severity factor. It was found that cleavage of LCC linkage was strongly pH-dependent. Low pH dominated cleavage of coumarate/ferulate esters which cross-linking lignin with xylan and repolymerization of aromatics either from furfural or lignin into polymers such as pseudo lignin, while high pH which allowed the existence of soluble LCC dominated the aldol condensations from xylose to aromatics and depolymerizaton of lignin to phenols. Detailed reaction pathways concerned with LCC were finally established to elucidate the underlying mechanism. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-05T11:00:37.263672-05:
      DOI: 10.1002/aic.16114
  • Bilevel and Parallel Programming-based Operability Approaches for Process
           Intensification and Modularity
    • Authors: Juan C. Carrasco; Fernando V. Lima
      Abstract: Process operability emerged in the last decades as a powerful tool for the design and control of chemical processes. Recent efforts in operability have been focused on the calculation of the desired input set for process design and intensification of natural gas utilization applications described by nonlinear models. However, there is still a gap in terms of problem dimensionality that nonlinear operability methods can handle. To fill this gap, in this paper, the incorporation of bilevel and parallel programming approaches into classical process operability concepts is discussed. Results on the implementation of the proposed method show a reduction in computational time up to 2 orders of magnitude, when compared to the original results without parallelization. These results could be extrapolated for use in a supercomputer as presented in the computational time analysis performed. In terms of intensification, the proposed approach can produce a natural gas combined cycle plant modular design with a dramatic reduction in size, from the original 400 to 0.11 [MW], while still keeping the high net plant efficiency. This approach thus provides a computationally efficient framework for process intensification of high-dimensional nonlinear energy systems towards modularity. The proposed approach also enables the verification of a modular design and conditions that can be obtained according to economic and physical constraints associated with a specific natural gas well production. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-05T11:00:31.014225-05:
      DOI: 10.1002/aic.16113
  • Universal Correlation for Gas Hydrates Suppression Temperature of
           Inhibited Systems: II. Mixed Salts and Structure Type
    • Authors: Yue Hu; Bo Ram Lee, Amadeu K. Sum
      Abstract: The first paper of this study discussed the development of the Hu-Lee-Sum (HLS) correlation and demonstrated the generality and universality of the correlation to predict structure I hydrates suppression temperature for any single salt system. However, natural gas commonly forms structure II hydrates, and mixed salts naturally occur in oil and gas production. Therefore, reliable prediction of structure II hydrates suppression temperature in presence of mixed salts over a wide range of pressure is considerably important. The contribution for each salt in salt mixtures is accounted for in the effective mole fraction to extend the HLS correlation for mixed salts systems. Moreover, a parameter (α) is introduced to account for the effect of hydrate structure on the hydrate suppression temperature. Herein, the HLS correlation is further shown to be universal and reliable to predict the hydrate suppression temperature for more complicated systems for mixed gases and mixed salts. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-05T11:00:27.417595-05:
      DOI: 10.1002/aic.16116
  • Bubble-separation dynamics in a planar cyclone: Experiments and CFD
    • Authors: Xiao Xu; Xiao-ling Ge, Yun-dong Qian, Hua-lin Wang, Qiang Yang
      Abstract: A planar cyclone is designed for visualizing bubbles in the cross-section of a degassing hydrocyclone. The pressure distribution is studied through a series of experiments and Reynolds stress model simulations. The velocity distribution of the planar cyclone mostly exhibits the quasi-forced vortex zone and boundary layer zone. The bubble dynamics are simulated using both Euler–Euler and Euler–Lagrange approaches, and the output is compared with the imaging results. The Euler–Euler simulation provides more accurate predictions of the bubble trajectory. The histograms of residence time and traveling distance given by the Euler–Lagrange approach exhibit a reasonably regular pattern. With higher values of the inlet Reynolds number, stronger forces acting on the bubbles lead to a decreased but more uniform residence time. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-05T10:55:56.558427-05:
      DOI: 10.1002/aic.16115
  • Predicting NRTL Binary Interaction Parameters from Molecular Simulations
    • Authors: Ashwin Ravichandran; Rajesh Khare, Chau-Chyun Chen
      Abstract: A predictive approach for calculating the binary interaction parameters (τij) of the nonrandom two liquid (NRTL) local composition model is developed, combining molecular simulations with the two-fluid theory. The binary interaction parameters are determined for the following three sets of model binary mixtures: water + methanol, methanol + methyl acrylate, and water + methyl acrylate. For each binary mixture, the interaction parameters are expressed in terms of molecular size and strength of interactions, which are in turn, calculated from molecular simulations. We show that the binary interaction parameters determined from simulations are in qualitative agreement with those estimated from regressing experimental data. The major factors that determine the binary interaction parameters are outlined based on simple thermodynamic arguments for each mixture. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-05T10:55:41.504496-05:
      DOI: 10.1002/aic.16117
  • Supra-Monolayer Coverages on Small Metal Clusters and Their Effects on H2
           Chemisorption Particle Size Estimates
    • Authors: Abdulrahman S. Almithn; David D. Hibbitts
      Abstract: H2 chemisorption measurements are used to estimate the size of supported metal particles, often using a hydrogen-to-surface-metal stoichiometry of unity. This technique is most useful for small particles whose sizes are difficult to estimate through electron microscopy or X-ray diffraction. Undercoordinated metal atoms at the edges and corners of particles, however, make up large fractions of small metal clusters, and can accommodate multiple hydrogen atoms leading to coverages which exceed 1 ML (supra-monolayer). Density functional theory was used to calculate hydrogen adsorption energies on Pt and Ir particles (38–586 atoms, 0.8–2.4 nm) at high coverages (≤ 3.63 ML). Calculated differential binding energies confirm that Pt and Ir (111) single-crystal surfaces saturate at 1 ML; however, Pt and Ir clusters saturate at supra-monolayer coverages as large as 2.9 ML. Correlations between particle size and saturation coverage are provided that improve particle size estimates from H2 chemisorption for Pt-group metals. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-02T17:53:06.076574-05:
      DOI: 10.1002/aic.16110
  • Dynamics of Pristine Graphite and Graphene at an Air-Water Interface
    • Authors: David M. Goggin; Joseph R. Samaniuk
      Abstract: We examine the dynamics and morphology of graphitic films at an air-water interface in a Langmuir trough by varying interfacial surface coverage, observing in situ interfacial structure, and by characterizing interfacial structure of depositions on mica substrates. In situ interfacial structure is visualized with Brewster angle microscopy, and depositions of the interface are characterized with atomic force microscopy and field-emission scanning electron microscopy. Compression/expansion curves exhibit a monotonically decreasing surface pressure between consecutive compressions, but demonstrate a “rebound” of hysteretic behavior when the interface is allowed to relax between consecutive compressions. This dynamic results from a competition between consolidation of the interface via agglomeration of particles or the stacking of graphene sheets, and a thermally driven relaxation where nanometer-thick particles are able to overcome capillary interactions. These results are especially relevant to applications where functional films with controlled conductivity and transparency may be produced via liquid-phase deposition methods. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-02T17:47:00.466695-05:
      DOI: 10.1002/aic.16112
  • Characterization of PVC-soy Protein Nonwoven Mats prepared by
    • Authors: HeeRan Hong; Zachary T. Tronstad, Yi Yang, Matthew D. Green
      Abstract: Poly(vinyl chloride) (PVC) is one of the most common polymers used in the water treatment industry due to outstanding hydrophobicity and mechanical strength. Generating eco-friendly membranes derived from natural polymers has gained attention, particularly for water purification and producing potable water. In this study, nonwoven mats were prepared by electrospinning polymer solutions. Mats with a tailorable hydrophilicity were prepared by electrospinning solution mixtures containing PVC and an eco-friendly, hydrophilic natural polymer: soy protein. As the viscosity of the solution decreased, the average fiber diameter and average pore surface area reduced. However, when the PVC concentration remained constant and the soy protein concentration increased, the viscosity decreased and average fiber diameter became reduced, while the average pore diameter remained relatively constant. The mats with volumetric ratios of PVC:soy protein of 85:15 and 80:20 displayed optimal characteristics suitable for mat fabrication based on the fiber diameter and average pore surface area. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-02T17:42:19.428434-05:
      DOI: 10.1002/aic.16109
  • An Evaluation of the Impact of SG1 Disproportionation and the Addition of
           Styrene in NMP of Methyl methacrylate
    • Authors: S.K. Fierens; P.H.M. Van Steenberge, F. Vermeire, Marie-Françoise Reyniers, Dagmar R. D'hooge, Guy B. Marin
      Abstract: A kinetic modeling study is presented for batch nitroxide mediated polymerization (NMP) of methyl methacrylate (MMA; nitroxide: N-tert-butyl-N-[1-diethylphosphono-(2,2-dimethylpropyl)] (SG1)). Arrhenius parameters for SG1 disproportionation (A = 1.4 107 L mol−1 s−1; Ea = 23 kJ mol−1) are reported, based on homopolymerization data accounting for unavoidable temperature variations with increasing time, i.e. non-isothermicity. For low targeted chain lengths (TCLs ≤ 300), this non-isothermicity is also relevant for NMP of MMA with a small amount of styrene. Parameter tuning to copolymerization data confirms a penultimate monomer unit effect for activation (sa2 = ka12/ka22=6.7; 363 K; 1: MMA; 2: styrene). To obtain, for a broad TCL range (up to 800), a dispersity well below 1.3 an initial styrene mass fraction of ca. 10% is required. An interpretation of the comonomer incorporation is performed by calculating the fractions of activation-growth-deactivation cycles with a given amount of monomer units and the copolymer composition distribution. This article is protected by copyright. All rights reserved.
      PubDate: 2018-02-02T17:41:10.038237-05:
      DOI: 10.1002/aic.16111
  • A Numerical Model of Exchange Chromatography Through 3D Lattice Structures
    • Authors: Maher Salloum; David B. Robinson
      Abstract: Rapid progress in the development of additive manufacturing technologies is opening new opportunities to fabricate structures that control mass transport in three dimensions across a broad range of length scales. We describe a structure that can be fabricated by newly available commercial 3D printers. It contains an array of regular three-dimensional flow paths that are in intimate contact with a solid phase, and thoroughly shuffle material among the paths. We implement a chemically reacting flow model to study its behavior as an exchange chromatography column, and compare it to an array of one-dimensional flow paths that resemble more traditional honeycomb monoliths. A reaction front moves through the columns and then elutes. The front is sharper at all flow rates for the structure with three-dimensional flow paths, and this structure is more robust to channel width defects than the one-dimensional array. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-30T13:00:55.872934-05:
      DOI: 10.1002/aic.16108
  • Scalar Mixing in Anisotropic Turbulent Flow
    • Authors: Quoc Nguyen; Dimitrios V. Papavassiliou
      Abstract: While turbulent mixing has been studied extensively in homogeneous turbulence, chemical engineering processes where mixing is important are anisotropic. In anisotropic turbulence, the interplay between convection and diffusion is critical. Flow in an infinite channel is utilized here with clouds of scalars released instantaneously at different distances from the wall and at Schmidt numbers between 0.7 and 2,400. Qualitative and quantitative measures of mixing efficiency and intensity are defined and the dynamics of mixing are explored. It is found that molecular diffusivity can even hinder mixing in some instances, because it affects the development of the cloud of the released scalars from regions within the viscous wall layer. Another finding is that while one would expect mixing to occur mostly in the space between two points of release, considerable amount of mixing could take place outside of this region and closer to the wall. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-29T10:55:43.669066-05:
      DOI: 10.1002/aic.16104
  • Hydrothermal Pretreatment for Deconstruction of Plant Cell Wall:Part II.
           Effect on Cellulose Structure and Bioconversion
    • Authors: Kun Yao; Qinfeng Wu, Ran An, Wei Meng, Mingzhu Ding, Bingzhi Li, Yingjin Yuan
      Abstract: Influences of both ultrastructural modification of cellulose after hydrothermal pretreatment and products derived from lignin-carbohydrate complex (LCC) on the subsequent enzymatic digestibility and fermentation were studied in this study. Under hydrothermal conditions, it was found that the rearrangement of hydrogen bonding pattern in cellulose via allomorph and conformational changes which was mainly severity-dependent increased the numbers of water-exposed glycosidic bond and the formation of “amorphous-like” cellulose fibril facilitated enzymatic hydrolysis. Pseudo lignin, soluble xylo-oligomers, phenols and degradation products from high severity impeded enzymatic digestion. LCC and phenols which were rich in pH-controlled prehydrolyzate did not sufficiently inhibit yeast while furans and some aromatics which were rich in high-severity prehydrolyzate might be potential inhibitors. Trade-off phenomenon was solved by pH-controlled operation and high yields in both glucose (83-93%) and xylose (75-80%) were simultaneously obtained. The final ethanol yield from cellulose to ethanol reached as high as 84-93%. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-29T10:55:37.778212-05:
      DOI: 10.1002/aic.16106
  • Removal of Yield-Stress Fluids from Pipework using Water
    • Authors: I. Palabiyik; E. Lopez-Quiroga, P.T. Robbins, K.R. Goode, P.J. Fryer
      Abstract: The emptying of product from process plant is a significant multiphase flow problem in food and personal care industries, controlling both product recovery and cleaning time. Product and operational losses can be significant, especially with viscous products. It is necessary to maximize product recovery whilst minimizing cleaning time and effluent volume. The removal of a range of products from fully filled pipework by using water has been characterised and monitored by weighing pipes at intervals and by inline turbidity probe. Data is presented for a range of products (toothpaste, hand cream, apple sauce, yoghurt and shower gel) that have been cleaned from two pipe systems. The data can be fitted by a linear relationship between a dimensionless cleaning time, and the ratio of the product yield stress to the surface shear stress. The effect of pipe fittings is to reduce cleaning times, reflecting increased shear/energy dissipation in the pipe. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-29T10:55:29.520375-05:
      DOI: 10.1002/aic.16105
  • Preparation of High-Performance zeolite NaA Membranes in Clear Solution by
           Adding SiO2 into Al2O3 Hollow-Fiber Precursor
    • Authors: Nanke Ma; Rui Wang, Gaohong He, Zhengbao Wang
      Abstract: Zeolite NaA membranes were prepared in a clear synthesis solution without the aid of nanoseeds. To improve the properties of the membranes formed in a clear solution, alumina hollow fibers were fabricated by adding silica powder to the conventional spinning slurry, resulting in hollow fibers with a mullite phase. Prior to the membrane synthesis, the hollow fibers were pretreated by dipping in an aged synthesis solution diluted with isopropanol. Dense zeolite NaA membranes on mullite-containing alumina hollow fibers were successfully obtained at 100°C for 2 h without the aid of nanoseeds. The membranes have a good pervaporation performance with a high flux of 10.8 kg m−2 h−1 and a separation factor of over 10,000. The abundant mullite-phase hydroxyl groups on the support surface promote the nucleation and growth of zeolite crystals on the support, resulting in dense membranes. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-29T10:46:21.812335-05:
      DOI: 10.1002/aic.16107
  • A Decomposition Algorithm for Simultaneous Scheduling and Control of CSP
    • Authors: Alexander W. Dowling; Tian Zheng, Victor M. Zavala
      Abstract: We present a decomposition algorithm to perform simultaneous scheduling and control decisions in concentrated solar power (CSP) systems. Our algorithm is motivated by the need to determine optimal market participation strategies at multiple timescales. The decomposition scheme uses physical insights to create surrogate linear models that are embedded within a mixed-integer linear scheduling layer to perform discrete (operational mode) decisions. The schedules are then validated for physical feasibility in a dynamic optimization layer that uses a continuous full-resolution dynamic CSP model. The dynamic optimization layer updates the physical variables of the surrogate models to refine schedules. We demonstrate that performing this procedure recursively provides high-quality solutions of the simultaneous scheduling and control problem. We exploit these capabilities to analyze different market participation strategies and to explore the influence of key design variables on revenue. Our results also indicate that using scheduling algorithms that neglect detailed dynamics significantly decreases market revenues. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-25T11:51:04.853432-05:
      DOI: 10.1002/aic.16101
  • Metal Nanoparticles in Ionic Liquid - Cosolvent Biphasic Systems as Active
           Catalysts for Acetylene Hydrochlorination
    • Authors: Lifeng Yang; Qiwei Yang, Jingyi Hu, Zongbi Bao, Baogen Su, Zhiguo Zhang, Qilong Ren, Huabin Xing
      Abstract: Ionic liquid (IL)-stabilized metal nanoparticles (NPs) have attracted increased attention as novel catalysts for various reactions due to their excellent stability and high activity. However, the high viscosity of ILs limits their applications. Here, for the first time, we reported an NPs@IL-cosolvent liquid-liquid biphasic system for metal NPs catalysis. The NPs were successfully confined to IL phase, and abundant IL droplets containing NPs were generated under the reactant flow. The NPs@IL droplets served as microreactors for the catalysis; while the low viscosity organic phase enabled the rapid mass transfer of substances. The biphasic system exhibited improved performance for acetylene hydrochlorination than that of the pure IL system. An acetylene conversion of 98% and a selectivity of 99.5% were achieved along with a 90% decrease on IL usage. The tolerable gas hourly space velocity in the biphasic system for a satisfactory conversion was almost double that of the pure IL system. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-25T11:50:54.384231-05:
      DOI: 10.1002/aic.16103
  • Method to Estimate Uncertainty Associated with Parcel Size in Coarse
           Discrete Particle Simulation
    • Authors: Liqiang Lu; Sofiane Benyahia
      Abstract: Coarse grained particle methods significantly reduce the computation cost of large-scale fluidized bed simulation by lumping many real particles into a computation parcel. This research provides a method to estimate the errors associated with parcel size in large-scale fluidized bed simulations. This uncertainty is first quantified in small scale domains by comparing results of discrete particle method with that employing coarse parcels of different sizes. Then, this uncertainty is correlated with parcel size and simulation domains consisting of a simple homogeneous cooling system and more complex bubbling and circulating fluidized beds. These correlations allow us to accurately estimate the uncertainty in large-scale fluidized beds based solely on data obtained in smaller systems. The ability to estimate model-related uncertainty in larger systems makes this method relevant for industrial applications. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-25T11:40:23.237862-05:
      DOI: 10.1002/aic.16100
  • Optimal design of batch-storage network considering ownership
    • Authors: Gyeongbeom Yi; Gintaras V. Reklaitis
      Abstract: This paper develops a model of multi-national supply chain activities, which incorporates currency storage units to manage currency flows associated with activities such as raw material procurement, processing, inventory control, transportation and finished product sales. The core contribution of this model is that it facilitates the quantitative investigation of the influence of macroscopic economic factors such as ownership on supply chain operational decisions. The supply chain system is modeled as a batch-storage network with recycle streams. The supply chain optimization problem is posed with the objective of minimizing the opportunity costs of annualized capital investments and currency/material inventories, while taking into account the benefit to stockholders in the numeraire currency. The major constraints on the optimization are that the material and currency storage units must not be depleted. A production and inventory analysis formulation (the periodic square wave model) provides useful expressions for the upper and lower bounds and for the average levels of the currency and material inventory holdings. The expressions for the Kuhn-Tucker conditions of the optimization problem are reduced to a subproblem that allows development of analytical lot-sizing equations. The lot sizes of procurement, production, transportation and financial transactions can be determined in closed form once the average flow rates are known. The key result we obtain is that optimal value of the economic order quantity changes substantially with variation in ownership, thus showing quantitatively that ownership structure does impact plant operation. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-25T11:20:33.845228-05:
      DOI: 10.1002/aic.16102
  • Atomic Layer Deposition Fabricating of Ceramic Nanofiltration Membranes
           for Efficient Separation of Dyes from Water
    • Authors: He Chen; Shanshan Wu, Xiaojuan Jia, Sen Xiong, Yong Wang
      Abstract: To meet the strong need for highly efficient and controllable manufacturing methods to ceramic nanofiltration (NF) membranes, we use atomic layer deposition (ALD) to prepare NF membranes by tightening ultrafiltration (UF) membranes. We confine the ALD deposition of TiO2 to the near-surface region of substrate UF membranes. The pores (∼ 5 nm) in the selective layers are progressively reduced, thus transforming the original UF membranes to NF ones at acceptable expense of permeability. A molecular-weight-cut-off (MWCO) down to 890 Da is obtained after merely 40 cycles and the water permeability remains as high as 32 L·m−2·h−1·bar−1. MWCOs can be flexibly tuned by altering ALD cycles, which is lowered down to 410 Da with 60 ALD cycles. The deposited membranes are used to remove dyes from water and they show significantly enhanced rejection to negatively charged dyes. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-21T05:16:00.017186-05:
      DOI: 10.1002/aic.16097
  • Real-time Multi-Variable Model Predictive Control (MPC) for Steam-Assisted
           Gravity Drainage (SAGD)
    • Authors: Sagar N Purkayastha; Ian D. Gates, Milana Trifkovic
      Abstract: Thermal recovery techniques, such as Steam-Assisted Gravity Drainage (SAGD), is used to recover the majority of the crude bitumen, in Western Canada. However, suboptimal production techniques have led to a large carbon footprint and a subsequent search for more efficient extraction techniques, than open loop manual control. This paper summarizes research on the comparison of performance of a novel Multi Input Multi Output (MIMO) Model Predictive Controller (MPC) with steam trap and oil rate controls with a Multi Input Single Output (MISO) MPC with only steam trap control. An appropriate system identification technique was also used for periodic model update in compliance with changing system behavior. The real time control study was made possible by establishing a bidirectional communication between Computer Modeling Group (CMG) STARSTM (virtual reservoir) and MATLAB (onsite controller) software. The results show a 171% improvement in oil recovery for the novel MIMO MPC over the MISO MPC. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-21T05:15:46.463946-05:
      DOI: 10.1002/aic.16098
  • Reduced power consumption in stirred vessels by means of fractal impellers
    • Authors: S. Başbuğ; G. Papadakis, J. C. Vassilicos
      Abstract: Earlier studies1,2 have shown that the power consumption of an unbaffled stirred vessel decreases significantly when the regular blades are replaced by fractal ones. In this paper, the physical explanation for this reduction is investigated using Direct Numerical Simulations at Re = 1600. The gaps around the fractal blade perimeter create jets that penetrate inside the recirculation zone in the wake and break up the trailing vortices into smaller ones. This affects the time-average recirculation pattern on the suction side. The volume of the separation region is 7% smaller in the wake of the fractal blades. The lower torque of the fractal impeller is equivalent to a decreased transport of angular momentum; this difference stems from the reduced turbulent transport induced by the smaller trailing vortices. The major difference in the turbulent dissipation is seen in the vicinity of trailing vortices, due to fluctuations of velocity gradients at relatively low frequencies. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-18T12:50:25.823794-05:
      DOI: 10.1002/aic.16096
  • Stochastic Back-off Algorithm for Simultaneous Design, Control and
           Scheduling of Multi-product Systems under Uncertainty
    • Authors: Robert W. Koller; Luis A. Ricardez-Sandoval, Lorenz T. Biegler
      Abstract: An algorithm that employs the back-off method to provide optimal solutions for integration of design, control, and scheduling for multi-product systems is presented, featuring a flexibility and feasibility analysis. The algorithm employs Monte Carlo (MC) sampling to generate a large number of random realizations, and simulate the system to determine feasibility. Back-off terms are determined and incorporated into a new flexibility analysis to approximate the effect of stochastic uncertainty and disturbances. Through successive iterations, the algorithm converges, terminating on a solution that is robust to a specified level of process variability due to stochastic realizations in the disturbances and uncertain parameters. The proposed algorithm has been successfully applied to a multi-product continuous stirred tank reactor for which optimal design, control, and scheduling decisions are identified, subject to stochastic uncertainty and disturbance. The present approach has been compared to a critical-set (multi-scenario) method showing the benefits and limitations of both approaches. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-17T11:45:41.009039-05:
      DOI: 10.1002/aic.16092
  • Ecosystems as Unit Operations for Local Techno-Ecological Synergy:
           Integrated Process Design with Treatment Wetlands
    • Authors: Varsha Gopalakrishnan; Bhavik R. Bakshi
      Abstract: Despite the critical importance of ecological systems for sustaining all chemical and manufacturing processes, process design has kept nature outside its system boundary. Recent efforts for sustainable process design aim to reduce environmental impact, but no design method considers the capacity of ecosystems to supply the goods and services that are needed to sustain a process. Overcoming this deficiency of conventional process design is essential to transform the chemical industry into an activity that respects ecological constraints and results in a net positive societal impact. As an important step toward meeting this goal, this work expands the boundary of process design to include ecosystems as unit operations in traditional design. Similar to tasks performed by conventional unit operations, ecological processes perform ecosystem functions resulting in goods and services required by the technological system. The goal behind designing integrated techno-ecological process flowsheets is to balance the ecosystem service demand of technological systems with the ecosystem service supply of ecological systems. Systems are optimized to balance the demand and supply subject to unit operation level constraints of technological and ecological systems, and interactions between detailed process level variables and ecological variables are explored. The Techno-Ecological Synergy (TES) Design method is developed and applied to a biofuel production system, considering ecosystem services like water provisioning and water quality regulation provided by wetland ecosystems. Comparing the integrated TES design with conventional techno-centric design shows that TES design can result in net positive impact manufacturing: a case where the ecosystem service supply is equal to or exceeds the demand, with little or no compromises in process profitability. These results should encourage close integration between technological and ecological systems while designing sustainable processes, and identify many challenges for developing TES of individual processes and across the life cycle. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-17T11:43:42.742612-05:
      DOI: 10.1002/aic.16093
  • Highly Efficient Methane Reforming over a Low-loading Ru/γ-Al2O3 Catalyst
           in a Pd-Ag Membrane Reactor
    • Authors: David S. A. Simakov; Yuriy Román-Leshkov
      Abstract: Natural gas can be reformed to syngas (CH4 + H2O = CO + 3H2), at temperatures above 850 °C. Membrane catalytic reformers can provide high CH4 conversions at temperatures below 650 °C, by separating H2 from the reactive mixture. Traditional Ni-based catalysts suffer from low activity at low temperatures and deactivate rapidly by coking, particularly at low steam/carbon ratios. In this study, an ultra-low loading (0.15 wt%) Ru/γ-Al2O3 catalyst was implemented in a lab-scale membrane reformer, using a supported 5μm Pd-Ag film membrane. Methane conversions above 90% were achieved at 650 °C, 8 bar, and H2O/CH4 = 2, 3 with contact times of ca. 10 s. The system generated up to 3.5 mol of ultra-pure H2 per mol of CH4 fed, with a maximum power density of 0.9 kW/L. No significant deactivation was observed after 200 h time on stream, even when using low H2O:CH4 ratios. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-17T11:43:05.959442-05:
      DOI: 10.1002/aic.16094
  • Continuous-Time Formulations for the Optimal Planning of Multiple
           Refracture Treatments in a Shale Gas Well
    • Authors: Diego C. Cafaro; Markus G. Drouven, Ignacio E. Grossmann
      Abstract: This work presents a continuous-time optimization model for planning multiple refracture treatments over the lifespan of a shale gas well. We demonstrate that continuous-time models can handle multiple restimulations very efficiently, increasing the net present value of the well development and refracturing plan. Well productivity is represented by a piecewise hyperbolic function, which accounts for when and how often the well has been refractured. We illustrate the application and effectiveness of the proposed approach for both the maximization of the total gas recovered and the maximization of the net present value. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-17T11:41:41.24767-05:0
      DOI: 10.1002/aic.16095
  • Impact of Diversity of Morphological Characteristics and Reynolds number
           on Local Hemodynamics in Basilar Aneurysms
    • Authors: Marjan Rafat; Mahsa Dabagh, Martin Heller, James D. Rabinov, Howard A. Stone, Amanda Randles, Debra T. Auguste
      Abstract: Morphological and hemodynamic parameters have been suggested to affect the rupture of cerebral aneurysms, but detailed mechanisms of rupture are poorly understood. The purpose of our study is to determine criteria for predicting the risk of aneurysm rupture, which is critical for improved patient management. Existing aneurysm hemodynamics studies generally evaluate limited geometries or Reynolds numbers (Re), which are difficult to apply to a wide range of patient-specific cases. We focused on the association between hemodynamic characteristics and morphology. We assessed several two-dimensional (2D) and three-dimensional (3D) idealized and physiological geometries to characterize the hemodynamic landscape between flow patterns. The impact of morphology on velocity and wall shear stress (WSS) profiles were evaluated. We found that slight changes in aneurysm geometry or Re result in significant changes in the hemodynamic and WSS profiles. Our systematic mapping and non-dimensional analysis qualitatively identify hemodynamic conditions that may predispose aneurysms to rupture. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-12T11:05:22.297615-05:
      DOI: 10.1002/aic.16091
  • A Square-Force Cohesion Model and its Extraction from Bulk Measurements
    • Authors: Peiyuan Liu; Casey Q. LaMarche, Kevin M. Kellogg, Christine M. Hrenya
      Abstract: Accurate modeling of interparticle forces in DEM is critical to predicting the rheology of cohesive particles. Rigorous cohesion models usually include parameters associated with particle surface roughness. However, both roughness measurement and its distillation into appropriate model parameters remain challenging. We propose a square-force cohesion model, where cohesive force remains constant until a cut-off separation, above which cohesion vanishes. We demonstrate the square-force model is a valid surrogate of more rigorous models. Specifically, when two parameters of square-force model are chosen to match the two key quantities governing dense and dilute flows, namely maximum cohesive force and critical cohesive energy31, respectively, DEM results using square-force and more rigorous models show good agreement. For practical application of the square-force model to lightly cohesive systems, a method is established to extract its parameters via defluidization, enabling determination of particle-particle cohesion from simpler bulk measurements than complicated and expensive scans on individual grains. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-11T11:21:07.514719-05:
      DOI: 10.1002/aic.16089
  • 3D Simulation of the Time-dependent Fluid Flow and Fouling Behavior in an
           Industrial Hollow Fiber Membrane Module
    • Authors: Liwei Zhuang; Gance Dai, Zhen-liang Xu
      Abstract: A novel three-dimensional CFD model has been developed on the basis of fluid flow in the shell and lumen sides, and permeation and fouling behavior in the porous membrane zone. The simulated 25-minute dead-end outside-in filtration process showed that the energy consumed by the inlet manifold decreases during the constant pressure filtration. The velocity and pressure distributions in the module change with time. Flux distribution both in the axial and radial directions becomes increasingly more uniform, so does the cake distribution. Flux distribution and cake distribution inter-adjust each other in different modes. A correlation equation has been developed to describe the relationship between the volumetric flow rate and accumulated water production. The correlation equation with simple experiment enables the dynamic evolution of energy consumed by shell inlet manifold to be presented, which can be the criterion of how well the shell inlet manifold or module has been designed. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-11T11:20:53.190384-05:
      DOI: 10.1002/aic.16090
  • Liquid-Liquid-Solid Mass Transfer and Phase Behavior of Heterogeneous
           Etherification of Glycerol with Isobutene
    • Authors: Jingjun Liu; Bolun Yang
      Abstract: Previous experiments observed auto-acceleration in the etherification of glycerol with isobutene. This paper engaged to uncover the reason for this phenomenon via investigating the heterogenicity, including liquid-liquid phase equilibrium and liquid-liquid-solid mass transfer, of the reaction system. Phase behavior analysis showed that the reaction mixture separates into two liquid phases during the whole course of the reaction. The produced mono ethers of glycerol thermodynamically promote the homogenization of the two liquid phases. The modeling results of liquid-liquid-solid mass transfer indicated that the resistance of mass transfer is insignificant during the reaction. The bulk compositions of the two liquid phases are very close to their corresponding equilibrium compositions. An increase of isobutene concentration in the reaction phase is believed to lead all reactions speeding up. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-11T11:20:34.597975-05:
      DOI: 10.1002/aic.16080
  • On the Mechanisms of Secondary Flows in a Gas Vortex Unit
    • Authors: Kaustav Niyogi; Maria M. Torregrosa, Vladimir N. Shtern, Guy B. Marin, Geraldine J. Heynderickx
      Abstract: The hydrodynamics of secondary flow phenomena in a disc-shaped gas vortex unit (GVU) is investigated using experimentally validated numerical simulations. The simulation using ANSYS FLUENT® v.14a reveals the development of a backflow region along the core of the central gas exhaust, and of a counterflow multi-vortex region in the bulk of the disc part of the unit. Under the tested conditions, the GVU flow is found to be highly spiraling in nature. Secondary flow phenomena develop as swirl becomes stronger. The backflow region develops first via the swirl-decay mechanism in the exhaust line. Near-wall jet formation in the boundary layers near the GVU end-walls eventually results in flow reversal in the bulk of the unit. When the jets grow stronger the counterflow becomes multi-vortex. The simulation results are validated with experimental data obtained from Stereoscopic Particle Image Velocimetry and surface oil visualization measurements. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-11T11:17:01.37428-05:0
      DOI: 10.1002/aic.16087
  • Flow Distribution of Hydrocarbon Fuel in Parallel Mini-Channels Heat
    • Authors: Yu Chen; Zhiliang Lei, Tianhao Zhang, Quan Zhu, Zewei Bao, Qiyi Zhang, Xiang-Yuan Li
      Abstract: In this paper, the flow distribution of the Chinese No. 3 jet fuel in parallel mini-channels heat exchanger under high temperature condition was investigated. The models of PFR and choked flow were established based on the real fluid model. The formation mechanism of flow maldistribution of the fuel in the freely-distributed channels was studied. It was found that: under low heat flux, the slight flow rate deviation will be spontaneously eliminated; under high heat flux, the slight deviation of flow rate and heat flux will be enlarged and result in the channel with smaller flow rate entering the coking region. The feasibility and influence factors of the control method of flow distribution based on choked flow were discussed. The experimental results indicated that the mini-channels fuel-cooled plate with choked flow could maintain uniform flow distribution when the total fuel outlet temperature reached 1035 K. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-11T11:10:30.909323-05:
      DOI: 10.1002/aic.16086
  • Non-spherical particles in a pseudo-2D fluidized bed: Experimental study
    • Authors: Vinay V. Mahajan; Tim M.J. Nijssen, Kay A. Buist, J. A. M. Kuipers, Johan T. Padding
      Abstract: Fluidization is widely used in industries and has been extensively studied, both experimentally and theoretically, in the past. However, most of these studies focus on spherical particles while in practice granules are rarely spherical. Particle shape can have a significant effect on fluidization characteristics. It is therefore important to study the effect of particle shape on fluidization behaviour in detail. In this study, experiments in pseudo-2D fluidized beds are used to characterize the fluidization of spherocylindrical (rod-like) Geldart D particles of aspect ratio 4. Pressure drop and optical measurement methods (DIA, PIV, PTV) are employed to measure bed height, particle orientation, particle circulation, stacking and coordination number. The commonly used correlations to determine the pressure drop across a bed of non-spherical particles are compared to experiments. Experimental observations and measurements have shown that rod-like particles are prone to interlocking and channelling behaviour. Well above the minimum fluidization velocity, vigorous bubbling fluidization is observed, with groups of interlocked particles moving upwards, breaking up, being thrown high in the freeboard region and slowly raining down as dispersed phase. At high flowrates, a circulation pattern develops with particles moving up through the center and down at the walls. Particles tend to orient themselves along the flow direction. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-05T10:50:43.158868-05:
      DOI: 10.1002/aic.16078
  • On the construction of binary mixture p-x and T-x diagrams from isochoric
    • Authors: Ian H. Bell; Ulrich K. Deiters
      Abstract: In this work we describe how to efficiently and reliably calculate p-x and T-x diagrams for binary mixtures of fluids. The method is based on the use of the Helmholtz energy density as the fundamental thermodynamic potential. Through the use of temperature and molar concentrations of the components as the independent variables, differential relationships can be constructed along the phase envelope surface, and this system of differential equations is then integrated to construct isotherms and isobars cutting through the phase envelope.The use of the Helmholtz energy density as the fundamental potential allows several models to be considered in this formalism, including cubic equations of state (Peng-Robinson, GC-VTPR, etc.) as well as high-accuracy multifluid equations of state (the so-called GERG mixture model). Examples of each class are presented, demonstrating the flexibility of this method. Source code, examples, and comprehensive analytic derivatives are provided in the supplemental material. This article is protected by copyright. All rights reserved.
      PubDate: 2018-01-03T10:41:32.191932-05:
      DOI: 10.1002/aic.16074
  • Issue Information – Table of Contents
    • Pages: 1161 - 1161
      PubDate: 2018-03-02T11:07:42.93799-05:0
      DOI: 10.1002/aic.15901
  • An interfacial curvature distribution model and phase inversion
    • Authors: A. Vikhansky
      Abstract: The state of the two-phase system is described by the interfacial curvature distribution. A phenomenological closure model is proposed for the exact (unclosed) equations. Parameters of the model are related to the existing correlations for drop size in stirred flows. If water is dispersed in oil, the curvature has a uni-modal distribution with a positive mode. When a control parameter, e.g., water volume fraction is increasing, the distribution becomes bi-modal with both negative and positive values. After a while, the phase inversion occurs, and the distribution becomes uni-modal with a negative mode. Going in the other direction the phase inversion happens at lower volume fraction of water, i.e., there is an ambivalent region, where both phases might be in the dispersed state. The model implies, that even if the conditions for phase inversion are met, there might be a significant delay before the new morphology is established. This article is protected by copyright. All rights reserved.
      PubDate: 2017-10-06T17:50:21.172204-05:
      DOI: 10.1002/aic.15992
  • Modeling and Prediction of Protein Solubility using the Second Osmotic
           Virial Coefficient
    • Authors: Marcel Herhut; Christoph Brandenbusch, Gabriele Sadowski
      Abstract: The development of a precipitation or crystallization step requires knowing the solubility of the target protein and its crystallization behavior in aqueous solutions at different pH, temperatures and in the presence of precipitating agents, especially salts. Within this work, a solubility model for proteins based on the second osmotic virial coefficient B22 is developed. For this, a relation between protein solubility and B22 was combined with the extended DLVO model. This solubility model was then used to model and also predict the protein solubility of lysozyme and monoclonal antibody for different salts, salt concentrations, and pH. The modeled as well predicted B22 and protein solubility data of lysozyme in the presence of sodium chloride and sodium p-toluenesulfonate and of a monoclonal antibody in the presence of ammonium sulfate at different pH shows good agreement with experimental data. This article is protected by copyright. All rights reserved.
      PubDate: 2017-09-01T10:42:19.405106-05:
      DOI: 10.1002/aic.15944
  • DEM study on the discharge characteristics of lognormal particle size
           distributions from a conical hopper
    • Authors: Ya Zhao; Shiliang Yang, Liangqi Zhang, Jia Wei Chew
      Pages: 1174 - 1190
      Abstract: This study employs the discrete element method (DEM) to investigate the impact of the widths of lognormal particle size distributions (PSDs) with the same mean particle diameter on hopper discharge behaviors, namely, discharge rate, particle velocities, and size-segregation. Results reveal that (i) the hopper discharge rate decreases as PSD width increases; (ii) the mean discharge rates are constant with time, but the fluctuations increase as the PSD width increases; (iii) the overall size-segregation increases with PSD width; (iv) the overall mean particle diameters of the narrower PSDs do not exceed the initial mean of 5 mm, whereas that of wider ones do; (v) the relationship between PSD width and particle velocities is non-monotonic with no consistent trends; and (vi) no direct correlation exists between particle velocity and size-segregation. The results here provide valuable insights on the behavior of the prevalent polydisperse mixtures in hoppers. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1174–1190, 2018
      PubDate: 2017-11-20T11:05:48.468679-05:
      DOI: 10.1002/aic.16026
  • DEM–PBM modeling of abrasion dominated ribbon breakage
    • Authors: Simone Loreti; Chuan-Yu Wu, Gavin Reynolds, Jonathan Seville
      Pages: 1191 - 1204
      Abstract: In dry granulation, fine cohesive powders are compacted into large multi-particle entities, i.e., briquettes, flakes, or ribbons. The powder compaction is generally followed by milling, a size reduction process, which is crucial to obtain the desired granule size or properties. Abrasion and impact are two primary mechanisms of comminution in ribbon milling, but they are not completely understood. The aim of this article was hence to investigate numerically the fragmentation process induced by abrasion during ribbon milling. The discrete element method (DEM) was employed to simulate abrasion tests, for which three-dimensional parallelepiped ribbons were generated using auto-adhesive elastic spheres. The fragmentation rate, and the fragments size and number were determined for various surface energies and abrasive velocities. The DEM results showed that the mass-equivalent fragment size distributions were bi-modal, similar to the experimental observations and the numerical results for impact-dominated ribbon milling reported in the literature. In addition, two quantities were determined from the DEM analysis, i.e., the number of large fragments and the fraction of fines, which was then integrated into the population balance models (PBM) so that a DEM–PBM multiscale modeling framework was developed to predict the granule size distribution during ribbon milling. The DEM–PBM results were compared with the experimental results reported in the literature, and a broad agreement was obtained, implying the proposed DEM–PBM can be used to analyse the ribbon milling behavior. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1191–1204, 2018
      PubDate: 2017-11-27T14:35:43.300717-05:
      DOI: 10.1002/aic.16005
  • Integrated solvent and process design for continuous crystallization and
           solvent recycling using PC-SAFT
    • Authors: Jiayuan Wang; Richard Lakerveld
      Pages: 1205 - 1216
      Abstract: Solvent usage is a major source of environmental waste in pharmaceutical industry. The current paradigm shift toward continuous manufacturing in pharmaceutical industry has renewed the interest in continuous crystallization, which offers the prospect of easy solvent recycling. However, the selection of solvents for an integrated crystallization processes is nontrivial due to the likely trade-off between optimal solvent properties for crystallization and solvent separation and recycling. A systematic approach for the simultaneous optimization of process conditions and solvent selection for continuous crystallization including solvent recycling is presented. A unified perturbed-chain statistical associating fluid theory model framework is applied to predict thermodynamic properties related to solubility and vapor-liquid equilibrium, which is integrated with a process model. A continuous mapping procedure is adopted to solve the optimization problem effectively. A case study based on continuous antisolvent crystallization of paracetamol with solvent separation via flash demonstrates the approach. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1205–1216, 2018
      PubDate: 2017-10-27T11:55:29.577221-05:
      DOI: 10.1002/aic.15998
  • Receding horizon optimal operation and control of a solar-thermal district
           heating system
    • Authors: Xiaodong Xu; Yuan Yuan, Stevan Dubljevic
      Pages: 1217 - 1233
      Abstract: This work focuses on the receding horizon optimal control for a solar-thermal district heating (STDH) system containing lumped parameter and distributed parameter subsystems. A common STDH system includes solar collector system, a short-term energy storage tank and a district heating loop system with a secondary gas boiler system. The inclusion or exclusion of these components leads to different operational and working modes. Detailed system description and mathematical models are provided, and three working modes are introduced and in each mode several operations are demonstrated and addressed. Single-objective and multiobjective problems are formulated. Moreover, in the mode where gas boiler system is included to help addressing the district heating demand, the internal model based boundary servo-control approach is proposed and applied to obtain desired boiler water temperatures such that the expected district heating demand can be satisfied. Moreover, a boundary state observer is designed for the considered solar collector system. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1217–1233, 2018
      PubDate: 2017-11-01T10:25:50.596104-05:
      DOI: 10.1002/aic.16007
  • Multivariable model predictive control of a novel rapid pressure swing
           adsorption system
    • Authors: Matthew D. Urich; Rama Rao Vemula, Mayuresh V. Kothare
      Pages: 1234 - 1245
      Abstract: A multivariable model predictive control (MPC) algorithm is developed for the control and operation of a rapid pressure swing adsorption (RPSA)-based medical oxygen concentrator. The novelty of the approach is the use of all four step durations in the RPSA cycle as independent manipulated variables in a truly multivariable context. The RPSA has a complex, cyclic, nonlinear multivariable operation that requires feedback control, and MPC provides a suitable framework for controlling such a multivariable system. The multivariable MPC presented here uses a quadratic optimization program with integral action and a linear model identified using subspace system identification techniques. The controller was designed and tested in simulation using a complex, highly coupled, nonlinear RPSA process model. The model was developed with the least restrictive assumptions compared to those reported in the literature, thereby providing a more realistic representation of the underlying physical phenomena. The resulting MPC effectively tracks set points, rejects realistic process disturbances and is shown to outperform conventional PID control. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1234–1245, 2018
      PubDate: 2017-11-02T10:05:54.056499-05:
      DOI: 10.1002/aic.16011
  • Joint capacity planning and distribution network optimization of coal
           supply chains under uncertainty
    • Authors: Rui-Jie Zhou; Li-Juan Li
      Pages: 1246 - 1261
      Abstract: A two-stage stochastic integer programming model is developed to address the joint capacity planning and distribution network optimization of multiechelon coal supply chains (CSCs) under uncertainty. The proposed model not only introduces the uses of compound real options in sequential capacity planning, but also considers uncertainty induced by both risks and ambiguities. Both strategic decisions (i.e., facility locations and initial investment, service assignment across the entire CSC, and option holding status) and scenario-based operational decisions (i.e., facility operations and capacity expansions, outsourcing policy, and transportation and inventory strategies) can be simultaneously determined using the model. By exploiting the nested decomposable structure of the model, we develop a new distributed parallel optimization algorithm based on nonconvex generalized Bender decomposition and Lagrangean relaxation to mitigate the computation resource limitation. One of the main CSCs in China is studied to demonstrate the applicability of the proposed model and the performance of the algorithm. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1246–1261, 2018
      PubDate: 2017-11-09T10:45:40.65258-05:0
      DOI: 10.1002/aic.16012
  • A branch and bound algorithm to solve large-scale multistage stochastic
           programs with endogenous uncertainty
    • Authors: Brianna Christian; Selen Cremaschi
      Pages: 1262 - 1271
      Abstract: The growth in computation complexity of multistage stochastic programs (MSSPs) with problem size often prevents its application to real-world size problems. We present two variants of branch-and-bound algorithm, which reduce the resource requirements for the generation and solution of large-scale MSSPs with endogenous uncertainty. Both variants use Knapsack-problem based Decomposition Algorithm (Christian and Cremaschi, Comput Chem Eng. 2015;74:34–47) to generate feasible solutions and primal bounds. First variant (PH-KDA) uses a progressive hedging dual-bounding approach; the second (OSS-KDA) solves the MSSP removing all nonanticipativity constraints. Both variants were used to solve several instances of the pharmaceutical clinical trial planning problem. The first iteration of both algorithms provides a feasible solution, and a primal bound and a dual bound for the problem. Although the dual-bounds of OSS-KDA were generally weaker than PH-KDA, they are generated considerably faster. For the seven-product case the OSS-KDA generated a solution with a gap of 9.92% in 115 CPU seconds. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1262–1271, 2018
      PubDate: 2017-11-20T11:10:37.182847-05:
      DOI: 10.1002/aic.16019
  • Uncertainty-conscious methodology for process performance assessment in
           biopharmaceutical drug product manufacturing
    • Authors: Gioele Casola; Hirokazu Sugiyama, Christian Siegmund, Markus Mattern
      Pages: 1272 - 1284
      Abstract: This work presents an uncertainty-conscious methodology for the assessment of process performance—for example, run time—in the manufacturing of biopharmaceutical drug products. The methodology is presented as an activity model using the type 0 integrated definition (IDEF0) functional modeling method, which systematically interconnects information, tools, and activities. In executing the methodology, a hybrid stochastic–deterministic model that can reflect operational uncertainty in the assessment result is developed using Monte Carlo simulation. This model is used in a stochastic global sensitivity analysis to identify tasks that had large impacts on process performance under the existing operational uncertainty. Other factors are considered, such as the feasibility of process modification based on Good Manufacturing Practice, and tasks to be improved is identified as the overall output. In a case study on cleaning and sterilization processes, suggestions were produced that could reduce the mean total run time of the processes by up to 40%. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1272–1284, 2018
      PubDate: 2017-11-20T11:15:27.744993-05:
      DOI: 10.1002/aic.16020
  • Synthesis of ternary distillation process structures featuring minimum
           utility cost using the IDEAS approach
    • Authors: Hiroshi Takase; Shinji Hasebe
      Pages: 1285 - 1294
      Abstract: A synthesis method for ternary distillation process structures is proposed on the basis of the infinite-dimensional state-space (IDEAS) approach. The proposed synthesis procedure consists of two steps. At the first step, the utility cost is minimized. The result of the first step contains many tiny flows among the modules because the number of flows is not included in the objective function. Then, at the second step, an evolutionary procedure for process simplification is executed. In this step, the weighted sum of flow rates is minimized recursively while updating the weights at each iteration. The practical process structure is finally determined from the result of the second simplification step. The developed synthesis procedure was applied to the separation problem of a ternary mixture consisting of benzene, toluene, and o-xylene. It demonstrated that the proposed procedure provides a process whose liquid composition profile is quite similar to that of a Petlyuk column. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1285–1294, 2018
      PubDate: 2017-11-24T12:40:28.052422-05:
      DOI: 10.1002/aic.16023
  • Robust stabilization of a two-stage continuous anaerobic bioreactor system
    • Authors: Zhaoyang Duan; Costas Kravaris
      Pages: 1295 - 1304
      Abstract: This article studies the problem of stabilizing a two-stage continuous bioreactor system. A simple dynamic model of the system is first introduced based on a detailed mass balance model, and then used to derive a constant-yield controller to stabilize the system at given design steady state conditions. Using Lyapunov stability analysis, this control law is proved to guarantee stability of the closed loop system over the entire positive orthant. Simulation results show the successful performance of the controller. The control law is proved to be robust with respect to errors in the kinetic parameters and in the inlet feed concentration, in the sense of preserving its stability region. Performance of the control system can be enhanced if a feed-forward measurement of the inlet feed concentration can be incorporated in the control law. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1295–1304, 2018
      PubDate: 2017-11-30T10:00:30.085711-05:
      DOI: 10.1002/aic.16033
  • Modeling the deposition of fluorescent whitening agents on cotton fabrics
    • Authors: Laura Bueno; Carlos Amador, Serafim Bakalis
      Pages: 1305 - 1316
      Abstract: The adsorption of two widely used fluorescent whitening agents (FWAs) on unbrightened cotton fabrics has been investigated as a function of temperature, hardness of the wash liquor, initial concentration of FWA in solution, and fabric to wash liquor ratio. Sorption efficiencies of FWAs have been studied using a UV spectrophotometry technique. A mechanistic model has been developed to describe the dissolution process of FWAs, convective mass transport into the fabrics, diffusion in the stagnant layer to the fabrics' surface, and adsorption of FWAs on cotton fabrics. Dual porosity of the fabrics (inter-yarn and intra-yarn porosity) has been considered by allowing two different regions (outer and inner areas of the cotton fabrics) where FWAs molecules can diffuse and adsorb. Good agreement between experimental and predicted whiteness benefit by the proposed mathematical model has been observed for the range of variables considered. © The
      Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of 2017 American Institute of Chemical Engineers AIChE J, 64: 1305–1316, 2018
      PubDate: 2017-10-27T12:10:38.173136-05:
      DOI: 10.1002/aic.16001
  • Low Reynolds number isotope transient kinetic modeling in isothermal
           differential tubular catalytic reactors
    • Authors: Masood Otarod; Ronald M. Supkowski
      Pages: 1317 - 1329
      Abstract: A novel method is presented for modeling steady state isotope transient kinetics of heterogeneous catalytic reactions when the flow regime is laminar and conversion is differential. It is based on a factorization theorem which is deduced from the observation that transport functions fluctuate radially in porous beds. Factorization separates the radial from axial and temporal coordinates of the flow rate and concentration functions. It is shown that in transient tracing with a differential conversion, the radial components of the transport functions in the material conservation equations can be integrated into constant parameters to be determined from experimental data. The method is in particular useful as the knowledge of the radial profile of velocity and other transport functions and parameters are not prerequisites for data correlation. The methodology was successfully applied to the adsorption of carbon monoxide in Boudouard reaction on an alumina supported palladium catalyst. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1317–1329, 2018
      PubDate: 2017-11-02T10:00:43.915135-05:
      DOI: 10.1002/aic.16006
  • 3D-foam-structured nitrogen-doped graphene-Ni catalyst for highly
           efficient nitrobenzene reduction
    • Authors: Zhiyong Wang; Yuan Pu, Dan Wang, Jie Shi, Jie-Xin Wang, Jian-Feng Chen
      Pages: 1330 - 1338
      Abstract: We report the preparation of a porous 3D-foam-structured nitrogen-doped graphene-Ni (NG/NF) catalyst and the evaluation of its performance in the reduction of nitrobenzene (NB) through detailed studies of the kinetics. The NG/NF catalyst showed a significantly higher reaction rate than pure Ni foam (NF). Moreover, the separation of the 3D-foam-structured catalyst from the products was more convenient than that of NG powdered catalysts. The obtained kinetics data fit well to the Langmuir-Hinshelwood model, with an error ratio below 10%. Density functional theory (DFT) calculations indicated that the adsorption of sodium borohydride (NaBH4) on the NG/NF surface was stronger than that of NB, which strongly agreed with the kinetic parameters determined from the Langmuir-Hinshelwood model. The excellent catalytic efficiency of the 3D-foam-structured catalyst combined with the knowledge of the kinetics data make this catalyst promising for application in larger scale nitrobenzene reduction. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1330–1338, 2018
      PubDate: 2017-11-06T10:25:36.526797-05:
      DOI: 10.1002/aic.16016
  • Insight in kinetics from pre-edge features using time resolved in situ XAS
    • Authors: N.V.R.A. Dharanipragada; Vladimir V. Galvita, Hilde Poelman, Lukas C. Buelens, Guy B. Marin, Alessandro Longo
      Pages: 1339 - 1349
      Abstract: The kinetics of reduction of a 10 wt %Fe2O3-MgAl2O4 spinel were investigated using XRD and time resolved Fe-K QXANES. The Rietveld refinement of the XRD pattern showed the replacement of Al with Fe in the spinel structure and the formation of MgFeAlOx. The XANES pre-edge feature was employed to study the reduction kinetics during H2-TPR (Temperature Programmed Reduction) up to 730°C. About 55% of the Fe3+ in MgFeAlOx was reduced to Fe2+. A shrinking core model, which takes into account both solid-state diffusion via an oxygen diffusion coefficient, and gas-solid reaction through a reaction rate coefficient, was applied. The activation energy for chemical reaction showed a linear dependence on the conversion, increasing from 104 to 126 kJ/mol over the course of material reduction. The good accordance between the shrinking core model description and the experimental data indicates that XANES pre-edge features can be used to correlate changes in material structure and reaction kinetics. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1339–1349, 2018
      PubDate: 2017-11-07T11:00:41.484742-05:
      DOI: 10.1002/aic.16017
  • A comparative kinetics study of CO2 absorption into aqueous DEEA/MEA and
           DMEA/MEA blended solutions
    • Authors: Wusan Jiang; Xiao Luo, Hongxia Gao, Zhiwu Liang, Bin Liu, Paitoon Tontiwachwuthikul, Xiayi Hu
      Pages: 1350 - 1358
      Abstract: The kinetics of CO2 absorption into aqueous solutions of N,N-diethylethanolamine (DEEA), and N,N-dimethylethanolamine (DMEA), and their blends with monoethanolamine (MEA) have been studied in a stopped-flow apparatus. The kinetics experiments were carried out at the concentrations of DEEA and DMEA varying from 0.075 to 0.175 kmol/m3, respectively, and that of MEA ranging between 0.0075 and 0.0175 kmol/m3, over the temperature range of 293–313 K. Two kinetics models are proposed to interpret the reaction in the blended amine systems and the results show that the model which incorporates the base-catalyzed hydration mechanism and termolecular mechanism resulted in a better prediction. Furthermore, the kinetics behaviors of CO2 absorption into two blended systems are comprehensively discussed according to their molecular structures. It can be concluded that the interaction between tertiary amines and primary amines as well as the alkyl chain length of tertiary amines have a significant influence on the kinetics. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1350–1358, 2018
      PubDate: 2017-11-22T13:20:27.812089-05:
      DOI: 10.1002/aic.16024
  • Studies on mild catalytic synthesis of methyl acrylate via one-step aldol
    • Authors: Gang Wang; Chidchon Sararuk, Zeng-Xi Li, Chun-Shan Li, Hui Wang, Suo-Jiang Zhang
      Pages: 1359 - 1372
      Abstract: One-step catalytic synthesis of methyl acrylate from methyl acetate and trioxane, with 90.7% yield and 91.8% selectivity, was realized at 10–25°5. NMR analysis confirmed the ester enolization with generation of [i-Pr2EtN-H]+[TfO]− in the presence of i-Pr2EtN and Bu2BOTf, which was affected by solvent and base. The depolymerization of trioxane into formaldehyde was catalyzed by Bu2BOTf. The in-situ catalytic mechanism and efficiency of [i-Pr2EtN-H]+[TfO]− was determined and analyzed. Mechanism-based kinetic and thermodynamic studies were conducted for better understanding of this route. Also the primary process design and product separation simulation were carried out. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1359–1372, 2018
      PubDate: 2017-11-27T14:25:35.336225-05:
      DOI: 10.1002/aic.16022
  • Highly efficient separation of strongly hydrophilic structurally related
           compounds by hydrophobic ionic solutions
    • Authors: Qiwei Yang; Shaocong Guo, Xianxian Liu, Zhiguo Zhang, Zongbi Bao, Huabin Xing, Qilong Ren
      Pages: 1373 - 1382
      Abstract: The selective separation of strongly hydrophilic structurally related compounds in aqueous solutions is a long-standing challenge due to a trade-off between separation selectivity and capacity. This work shows a new method to separate strongly hydrophilic structurally related compounds through hydrophobic ionic solution-based liquid-liquid extraction, with L-ascorbic acid 2-glucoside (AA-2G) and L-ascorbic acid as model compounds. Extraordinary distribution coefficient, superb molecular selectivity, large extraction capacity and good recyclability without using strong acids and salts were all achieved, with a small consumption of phosphonium bromide ionic liquid and aprotic molecular diluent. The essence of this method is the successful combination of both strong hydrogen-bond basicity and good hydrophobicity along with significant preferential solvation phenomena of the constructed ionic solutions. Even if at a high feed concentration of 100 mg/mL, the purity of AA-2G could be greatly elevated from 50% to 96.2% with an ultrahigh yield of almost 100% after five-stage countercurrent extraction. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1373–1382, 2018
      PubDate: 2017-11-01T10:30:28.007818-05:
      DOI: 10.1002/aic.16013
  • Simulation on hydrogen storage properties of metal-organic frameworks
           Cu-BTC at 77–298 K
    • Authors: Shumin Chen; Yumei Shi, Bo Gu
      Pages: 1383 - 1388
      Abstract: In recent years, many researchers have studied on the hydrogen storage properties of metal-organic frameworks (MOFs) by grand canonical Monte Carlo (GCMC) simulation. At present, the GCMC studies of Cu-BTC (BTC: benzene-1,3,5-tricarboxylate) which is a prototypical metal-organic framework mainly adopt the classical force fields, the simulation temperatures are mainly focus on 298 and 77 K, and most researchers did not consider the effects of quantum effects at low temperature. Therefore, we used the quantum effects to correct the classical force fields and the force fields with more accurate simulation results were used to simulate the hydrogen adsorption performances of Cu-BTC in the temperature range of 77–298 K and the pressure range of 1–8 MPa at each temperature. The results show that the effects of quantum effects on the hydrogen storage of Cu-BTC cannot be neglected and the corrected Dreiding force field can simulate hydrogen adsorption performances of Cu-BTC more accurately at low temperature. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1383–1388, 2018
      PubDate: 2017-10-27T12:15:24.675186-05:
      DOI: 10.1002/aic.16008
  • Materials genomics-guided ab initio screening of MOFs with open copper
           sites for acetylene storage
    • Authors: Ce Zhang; Youshi Lan, Xiangyu Guo, Qingyuan Yang, Chongli Zhong
      Pages: 1389 - 1398
      Abstract: Discovering high-performance metal-organic frameworks (MOFs) with open metal sites has become an increasingly hot research topic in the field of safe storage and transportation of acetylene. Following the concept of Materials Genomics proposed recently, a database of 502 experimental MOFs was built by searching the structures deposited in the CSD with the dicopper paddle-wheel node Cu2(COO)4 as the characteristic materials gene. On the basis of the developed ab initio force field, a high-throughput computational screening was conducted to examine the property-performance relationships of MOFs containing Cu-OMS for C2H2 storage at ambient conditions. The optimal ranges of the structural and energetic features for the design of such MOFs were suggested. From our computational screening, three potentially promising MOFs were identified which exhibit a performance outperforming those MOFs reported experimentally so far with record high gravimetric C2H2 uptakes, both in the total and deliverable adsorption capacities. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1389–1398, 2018
      PubDate: 2017-11-21T09:55:38.67604-05:0
      DOI: 10.1002/aic.16025
  • Chemical hydrodynamics of a downward microbubble flow for intensification
           of gas-fed bioreactors
    • Authors: Manizheh Ansari; Damon E. Turney, Roman Yakobov, Dinesh V. Kalaga, Simon Kleinbart, Sanjoy Banerjee, Jyeshtharaj B. Joshi
      Pages: 1399 - 1411
      Abstract: Bioreactors are of interest for value-upgrading of stranded or waste industrial gases. Reactor intensification requires development of low cost bioreactors with fast gas–liquid mass transfer rate. Here we assess published reactor technology in comparison with a novel downward bubble flow created by a micro-jet array. Compared to known technology, the advanced design achieves higher volumetric gas transfer efficiency (kLa per power density) and can operate at higher kLa. We measure the effect of four reactor heights (height-to-diameter ratios of 12, 9, 6, and 3) on the gas transfer coefficient kL, total interfacial area a, liquid residence time distribution, energy consumption, and turbulent hydrodynamics. Leading models for predicting kL and a are appraised with experimental data. The results show kL is governed by “entrance effects” due to Higbie penetration dominate at short distances below the micro-jet array, while turbulence dominates at intermediate distances, and finally terminal rise velocity dominates at large distances. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1399–1411, 2018
      PubDate: 2017-10-27T12:05:30.289603-05:
      DOI: 10.1002/aic.16002
  • Liquid–liquid two-phase flow in ultrasonic microreactors: Cavitation,
           emulsification, and mass transfer enhancement
    • Authors: Shuainan Zhao; Zhengya Dong, Chaoqun Yao, Zhenghui Wen, Guangwen Chen, Quan Yuan
      Pages: 1412 - 1423
      Abstract: The effects of ultrasound on the hydrodynamic and mass transfer behaviors of immiscible liquid–liquid two-phase flow was investigated in a domestic ultrasonic microreactor. Under ultrasonic irradiation, cavitation bubble was generated and underwent violent oscillation. Emulsification of immiscible phases was initiated by virtue of oscillating bubbles shuttling through the water/oil interface. The pressure drop was found to decrease with increasing ultrasound power, with a maximum decrement ratio of 12% obtained at power 30 W. The mass transfer behavior was characterized by extraction of Rhodamine B from water to 1-octanol. An enhancement factor of 1.3–2.2 on the overall mass-transfer coefficient was achieved under sonication. The mass transfer performance was comparable to passive microreactor at similar energy dissipation rate (61–184 W/kg). The extraction equilibrium was reached under a total flow velocity 0.01 m/s and input power 20 and 30 W, exhibiting its potential use in liquid-liquid extraction process. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1412–1423, 2018
      PubDate: 2017-10-27T12:20:59.57062-05:0
      DOI: 10.1002/aic.16010
  • Improving mixing characteristics with a pitched tip in kneading elements
           in twin-screw extrusion
    • Authors: Yasuya Nakayama; Hiroki Takemitsu, Toshihisa Kajiwara, Koichi Kimura, Takahide Takeuchi, Hideki Tomiyama
      Pages: 1424 - 1434
      Abstract: In twin-screw extrusion, the geometry of a mixing element mainly determines the basic flow pattern, which eventually affects the mixing ability as well as the dispersive ability of the mixing element. The effects of geometrical modification, with both forward and backward pitched tips, of a conventional forward kneading disks element (FKD) in the pitched-tip kneading disks element on the flow pattern and mixing characteristics are discussed. Numerical simulations of fully filled, nonisothermal polymer melt flow in the melt-mixing zone were performed, and the flow pattern structure and the tracer trajectories were investigated. The pitched tips largely affect the inter-disk fluid transport, which is mainly responsible for mixing. These changes in the local flow pattern are analyzed by the distribution of the strain-rate state. The distribution of the finite-time Lyapunov exponent reveals a large inhomogeneity of the mixing in FKD is suppressed both by the forward and backward tips. By the forward tips on FKD, the mixing ability is relatively suppressed compared to FKD, whereas for the backward tips on FKD, the mixing ability is enhanced while maintaining the same level of dispersion efficiency as FKD. From these results, the pitched tips on the conventional KD turn out to be effective at reducing the inhomogeneity of the mixing and tuning the overall mixing performance. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1424–1434, 2018
      PubDate: 2017-10-30T09:06:06.68121-05:0
      DOI: 10.1002/aic.16003
  • A pore network study of evaporation from the surface of a drying
           non-hygroscopic porous medium
    • Authors: Alireza Attari Moghaddam; Abdolreza Kharaghani, Evangelos Tsotsas, Marc Prat
      Pages: 1435 - 1447
      Abstract: The phenomena occurring at the surface of a porous medium during drying in the capillary regime are investigated by pore network simulations. The impact of the formation of wet and dry patches at the surface on the drying rate is studied. The simulations indicate an edge effect characterized by a noticeable variation of saturation in a thin layer adjacent to the porous surface. Also, the results indicate a significant nonlocal equilibrium effect at the surface. The simulation results are exploited to test Schlünder's classical model which offers a simple closure relationship between the evaporation rate and the degree of occupancy of the surface by the liquid. In addition to new insights into the surface phenomena, the results open up new prospects for improving the continuum models of the drying process. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1435–1447, 2018
      PubDate: 2017-10-30T08:55:49.598814-05:
      DOI: 10.1002/aic.16004
  • Effect of viscosity on liquid curtain stability
    • Authors: Alireza Mohammad Karim; Wieslaw J. Suszynski, Lorraine F. Francis, Marcio S. Carvalho
      Pages: 1448 - 1457
      Abstract: The effect of viscosity on liquid curtain stability was explored by high-speed visualization. Measurements of the velocity within the curtain revealed the presence of a viscous boundary layer along the edge guides. The critical condition at the onset of curtain breakup was determined by identifying the flow rate below which the curtain broke for two different edge guide geometries: parallel and convergent. Curtain breakup was initiated by the expansion of a hole within the curtain. For low viscosity liquid, the measured hole retraction speed is independent of the viscosity and equal to the Taylor-Culick speed. For high viscosity liquids, the retraction speed is lower than the Taylor-Culick speed due to viscous forces that resist the flow. The results also show the effect of liquid viscosity on the curtain stability is a strong function of the edge guide design. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1448–1457, 2018
      PubDate: 2017-11-06T10:31:12.407737-05:
      DOI: 10.1002/aic.16015
  • Numerical simulation on flow behavior of twin-liquid films over a vertical
           plate with an open window
    • Authors: Hanguang Xie; Jianguang Hu, Gance Dai
      Pages: 1458 - 1468
      Abstract: A novel element for gas–liquid contact, a plate with rectangular windows was designed to enhance absorption process. Coexistence and interaction of wall-bounded films and confined free films named as “twin-liquid films” were observed on the plate. Volume of fluid (VOF) method was used to simulate its flow behavior. Flow phenomena such as flow around a step-in, jet impingement, varicose waves, and sinuous waves were observed. Different from thin films flow on an unperforated plate, larger mean velocity, thinner film thickness, more intensive capillary waves, and stronger vorticity on the free surfaces were detected inside the window, and the disturbances could propagate over the whole plate. Three-dimensional simulation results generally agreed with our experimental observations and further demonstrated complex wavy structures both inside and outside the window. The results would broaden traditional knowledge of liquid films flow and clarify the mechanism of mass transfer intensification for the plate with windows. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1458–1468, 2018
      PubDate: 2017-11-22T13:25:30.136213-05:
      DOI: 10.1002/aic.16021
  • More comprehensive 3D modeling of clay-like material drying
    • Authors: M. Heydari; K. Khalili, S. Y. Ahmadi-Brooghani
      Pages: 1469 - 1478
      Abstract: Drying process plays an important role in the manufacturing of many products such as ceramic, kitchenware and building materials, some of which have complex three-dimensional (3D) geometry. To deal with many restrictions found in literatures, a 3D numerical approach was used to describe the drying process of a porous Clay-like material. The problem investigated involves highly coupled equations considering heat, mass, and mechanical aspects. The model is validated through the comparison of experimental measurements with simulation result. Simulation results show that increasing the initial moisture content and reducing the initial temperature have the same privilege and without significant increase in drying time, it reduces slightly the amount of maximum stress but delays the occurrence time of maximum stress. The nonuniform heat expansion induced stresses are very small in comparison to nonuniform moisture shrinkage induced stresses and can be neglected in drying simulation. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1469–1478, 2018
      PubDate: 2017-11-22T13:20:34.476217-05:
      DOI: 10.1002/aic.16027
  • Analysis of North-American Tight oil production
    • Authors: Raul Velasco; Palash Panja, Manas Pathak, Milind Deo
      Pages: 1479 - 1484
      Abstract: North-American tight oil production has been on the rise due to the introduction of new drilling and hydraulic fracturing technologies. Such advances have dramatically changed the conventional understanding of the hydrocarbon recovery process. A dimensionless study of tight oil production across the United Sates in plays such as the Bakken, Niobrara, Eagle Ford, Woodford, Bone Spring, and Wolfcamp shed light on some of these recovery processes. Production from any well, regardless of geologic attributes and operating conditions, fits into a universal curve during its initial productive period. Subsequently, production becomes a strong function of hydrocarbon thermodynamics and multiphase flow. Results from this analysis help rank important parameters that affect oil recovery in terms of how wells are operated and the reservoir's intrinsic geological and fluid properties. Furthermore, production results are combined with a simple dimensionless economic analysis to determine optimal fracture configurations independent of oil price environment. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1479–1484, 2018
      PubDate: 2017-11-30T10:15:32.125179-05:
      DOI: 10.1002/aic.16034
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