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  Subjects -> ENGINEERING (Total: 2284 journals)
    - CHEMICAL ENGINEERING (192 journals)
    - CIVIL ENGINEERING (184 journals)
    - ELECTRICAL ENGINEERING (102 journals)
    - ENGINEERING (1208 journals)
    - ENGINEERING MECHANICS AND MATERIALS (389 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (65 journals)
    - MECHANICAL ENGINEERING (89 journals)

ENGINEERING (1208 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Hybrid Journal   (Followers: 5)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 227)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 6)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Artificial Neural Systems     Open Access   (Followers: 4)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 10)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 25)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 37)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 29)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 9)
Applied Clay Science     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
Applied Nanoscience     Open Access   (Followers: 7)
Applied Network Science     Open Access  
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 7)
Arid Zone Journal of Engineering, Technology and Environment     Open Access  
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
Batteries     Open Access   (Followers: 4)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 3)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 9)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 32)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 3)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 14)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 41)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 3)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 5)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 4)
Coatings     Open Access   (Followers: 3)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 26)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 254)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 179)
Composites Part B : Engineering     Hybrid Journal   (Followers: 227)
Composites Science and Technology     Hybrid Journal   (Followers: 192)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 13)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 28)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 10)
Computing and Visualization in Science     Hybrid Journal   (Followers: 5)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 30)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 8)
Control Engineering Practice     Hybrid Journal   (Followers: 42)
Control Theory and Informatics     Open Access   (Followers: 7)
Corrosion Science     Hybrid Journal   (Followers: 25)
CT&F Ciencia, Tecnologia y Futuro     Open Access  

        1 2 3 4 5 6 7 | Last

Journal Cover AIChE Journal
  [SJR: 1.122]   [H-I: 120]   [29 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0001-1541 - ISSN (Online) 1547-5905
   Published by John Wiley and Sons Homepage  [1584 journals]
  • Modular Manufacturing Processes: Status, Challenges and Opportunities
    • Authors: Michael Baldea; Thomas F. Edgar, Bill L. Stanley, Anton A. Kiss
      Abstract: Chemical companies are constantly seeking new, high-margin growth opportunities, the majority of which lie in high-grade, specialty chemicals, rather than in the bulk sector. In order to realize these opportunities, manufacturers are increasingly considering decentralized, flexible production facilities: large-scale production units are uneconomical for innovative products with a short lifespan and volatile markets. Small modular plants have low financial risks, are flexible and can respond rapidly to changes in demand. Logistics costs can be also reduced by moving production closer to customers and/or sources of raw materials. Moreover, stricter safety regulations can in many cases be more easily met using smaller distributed facilities.Modularization of chemical production can thus have potentially significant economic and safety ben- efits. In this article, we review several drivers for modular production, and evaluate modular production architectures based on the value density of feedstock resources and markets for the products of a process. We also discuss the links between modularization and process intensification. We illustrate the discussion with an array of industrial examples, which we also use to motivate a summary of challenges and future directions for this area. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-18T10:55:37.449298-05:
      DOI: 10.1002/aic.15872
       
  • COSMO-based computer-aided molecular/mixture design: A focus on reaction
           solvents
    • Authors: Nick D. Austin; Nikolaos V. Sahinidis, Ivan A. Konstantinov, Daniel W. Trahan
      Abstract: In this article, we investigate reaction solvent design using COSMO-RS thermodynamics in conjunction with computer-aided molecular design (CAMD) techniques. CAMD using COSMO-RS has the distinct advantage of being a method based in quantum chemistry, which allows for the incorporation of quantum-level information about transition states, reactive intermediates, and other important species directly into CAMD problems. This work encompasses three main additions to our previous framework for solvent design1: (1) altering the group contribution method to estimate hydrogen-bonding and non-hydrogen-bonding σ-profiles; (2) ab initio modeling of strong solute/solvent interactions such as H-bonding or coordinate bonding; and (3) solving mixture design problems limited to common laboratory and industrial solvents. We apply this methodology to three diverse case studies: accelerating the reaction rate of a Menschutkin reaction, controlling the chemoselectivity of a lithiation reaction, and controlling the chemoselectivity of a nucleophilic aromatic substitution reaction. We report improved solvents/mixtures in all cases. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-13T03:30:21.889893-05:
      DOI: 10.1002/aic.15871
       
  • The Maximum Flammable Content for Binary Aqueous–Organic Mixtures Not to
           Flash and their Maximum Flash Points
    • Authors: Horng-Jang Liaw
      Abstract: Aqueous–organic solutions can flash only over a limited composition range. This manuscript proposes a model to estimate the two critical parameters, maximum flammable content not to flash and the maximum flash point temperature, in judging whether an aqueous–organic solution is flammable or not. The results are applicable to flammability elimination and flammability hazard assessment of liquid solutions. Validation of this model was performed with measurements for 14 aqueous–organic miscible and partially miscible mixtures. Various mixtures were tested including alcohols, ketones, and esters in aqueous solutions. Overall, the estimation of the maximum flash point value and maximum flammable content not to flash were acceptable when using the proposed model. The termination of the flash for aqueous solutions was clarified to be the non-flammability of the vapor phase resulting from the high steam concentration when the temperature of such solutions is greater than the maximum flash point. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-12T13:10:32.304053-05:
      DOI: 10.1002/aic.15867
       
  • Design of Mixed Energy-integrated Batch Process Networks by Pseudo-direct
           Approach
    • Authors: Parikshit S. Shahane; Channamallikarjun S. Mathpati, Sujit S. Jogwar
      Abstract: In this paper, a novel framework for the design of mixed (combined direct and indirect) integration for batch process systems is presented. The framework is based on the concept of pseudo-direct energy integration (PDEI) which reformulates indirect integration as direct integration using pseudo-process streams. Two algorithms are presented to achieve energy integration for batch processes operating cyclically (in a campaign mode). The first algorithm targets maximization of energy recovery and overcomes the limitations of some of the existing contributions for design of mixed integrated systems. The second algorithm provides a network reduction methodology to generate a cadre of integrated designs while exploring the trade off between capital (number of heat exchangers and storage units) and operating costs (utility consumption). The proposed framework is illustrated using a benchmark example of two hot and two cold streams. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-12T13:10:30.51338-05:0
      DOI: 10.1002/aic.15869
       
  • Quantifying the Uncertainty Introduced by Discretization and
           Time-Averaging in Two-Fluid Model Predictions
    • Authors: Madhava Syamlal; Ismail Celik, Sofiane Benyahia
      Abstract: The two-fluid model (TFM) has become a tool for the design and troubleshooting of industrial fluidized bed reactors. To use TFM for scale up with confidence, the uncertainty in its predictions must be quantified. Here we study two sources of uncertainty: discretization and time-averaging. First, we show that successive grid refinement may not yield grid-independent transient quantities, including cross-section-averaged quantities. Successive grid refinement would yield grid-independent time-averaged quantities on sufficiently fine grids. Then a Richardson extrapolation can be used to estimate the discretization error, and the grid convergence index gives an estimate of the uncertainty. Richardson extrapolation may not work for industrial-scale simulations that use coarse grids. We present an alternative method for coarse grids and assess its ability to estimate the discretization error. Second, we assess two methods (autocorrelation and binning) and find that the autocorrelation method is more reliable for estimating the uncertainty introduced by time-averaging TFM data. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-12T13:10:27.598574-05:
      DOI: 10.1002/aic.15868
       
  • Biochar Soil Amendments for Increased Crop Yields: How to design a
           “designer” biochar
    • Authors: Kyriacos Zygourakis
      Abstract: This study presents the development and testing of a transient adsorption/desorption model that describes the response of biochar particles to nutrient pulses simulating the application of fertilizer. Intraparticle nutrient transfer occurs both by diffusion through liquid-filled pores and by surface diffusion, and nutrient adsorption is described by Langmuir-Freundlich (Sips) isotherms. Simulation results show that the ability of a biochar to adsorb and then slowly release the nutrient is modulated by a complex interplay of external mass transfer, intraparticle diffusion (both pore and surface diffusion), and adsorption dynamics. The nutrient retention potential of biochar-amended soils is quantified and is shown to depend on multiple factors that include chemical and physical biochar properties, soil permeability, water flow and the method of fertilizer application. These findings may explain why biochars with similar properties can potentially have widely different impacts on crop yields, as has been repeatedly reported in the literature. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-12T13:10:21.010583-05:
      DOI: 10.1002/aic.15870
       
  • Improving the Design of Depth Filters: A Model-Based Method Using Optimal
           Control Theory
    • Authors: Michael Kuhn; Christoph Kirse, Heiko Briesen
      Abstract: Because there is no general design method for depth filters, especially for layered configurations, we here address this methodological gap. Using optimal control theory, paths of the filter coefficient, a measure for local filtration performance, are determined along the filter depth. An analytical optimal control solution is derived and used to validate the numerical algorithm. Two optimal control scenarios are solved numerically: In the first scenario, the goal of constant deposition along the filter depth is addressed. The second scenario aims at maximizing the time until some maximal pressure drop is reached. Furthermore, we present a computational strategy to derive discrete layers suitable for practical design from the continuous optimal control solutions. All optimized scenarios are compared to one-layered filter designs and significant improvements are found. As this work is based on strongly validated and widely used filtration models, the presented methods are expected to have broad applicability. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-12T13:05:21.372076-05:
      DOI: 10.1002/aic.15866
       
  • Next generation of low global warming potential refrigerants:
           Thermodynamic properties molecular modeling
    • Authors: Wael A. Fouad; Lourdes F. Vega
      Abstract: The recent global agreement signed in Kigali to limit the use of hydrofluorocarbons (HFCs) as refrigerants, starting by 2019, has promoted an active area of research towards the development of low Global Warming Potential (GWP) new refrigerants. Hydrofluoroolefins (HFOs) have been proposed as a low GWP alternative to third generation HFC refrigerants, but further work on fully characterizing them and their blends with other compounds is still required to fully assess their performance to replace the ones in current use. In this work, the polar and perturbed chain statistical associating fluid theory (Polar PC-SAFT) coupled with the density gradient theory is used to predict the vapor-liquid equilibrium, isobaric heat capacity, speed of sound and surface tension of selected HFC and HFO based commercial azeotropic blends as fourth generation low GWP refrigerants, seeking for a predictive tool for these properties. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T11:05:50.869683-05:
      DOI: 10.1002/aic.15859
       
  • Design and Assessment of Delay Timer Alarm Systems for Nonlinear Chemical
           Processes*
    • Authors: Aditya Tulsyan; Feras Alrowaie, R. Bhushan Gopaluni
      Abstract: In process and manufacturing industries, alarm systems play a critical role in ensuring safe and efficient operations. The objective of a standard industrial alarm system is to detect undesirable deviations in process variables as soon as they occur. Fault detection and diagnosis (FDD) systems often need to be alerted by an industrial alarm system; however, poorly designed alarms often lead to alarm flooding and other undesirable events. In this paper, we consider the problem of industrial alarm design for processes represented by stochastic nonlinear time-series models. The alarm design for such complex processes faces three important challenges: 1) industrial processes exhibit highly nonlinear behavior; 2) state variables are not precisely known (modeling error); and 3) process signals are not necessarily Gaussian, stationary or uncorrelated. In this paper, a procedure for designing a delay timer alarm configuration is proposed for the process states. The proposed design is based on minimization of the rate of false and missed alarm rates – two common performance measures for alarm systems. To ensure the alarm design is robust to any non-stationary process behavior, an expected-case and a worst-case alarm designs are proposed. Finally, the efficacy of the proposed alarm design is illustrated on a non-stationary chemical reactor problem. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T11:05:08.150056-05:
      DOI: 10.1002/aic.15860
       
  • Numerical and Experimental Investigation on Surface Air Entrainment
           mechanisms of a Novel Long-Short Blades Agitator
    • Authors: Yueqiao Zhang; Xiang Pan, Yaohua Wang, Peicheng Luo, Hua Wu
      Abstract: We investigate numerically and experimentally the mechanisms of surface air entrainment in the vessels equipped with the long-short blades agitator. VOF method coupled with LES model is used to visualize the surface air entrainment process. In the case of partial submergence of the long blades (LBs), the interaction of the LBs with the liquid free surface creates a depression behind the LBs. Backfilling of the liquid into the depression leads to gas separation and entrapping into the liquid. The critical tip velocity of the LBs, utip,c, for the onset of gas entrainment is measured in vessels with diameters, T = 200∼600mm. It is found that when H/T≥1.0, utip,c is determined by the LBs, independent of the liquid level. utip,c is also affected by the size of the vessel through the diameter of the sweeping circle of the LBs, but for substantially large vessels, it approaches a constant value. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T11:05:06.161132-05:
      DOI: 10.1002/aic.15865
       
  • Generalized Gibbs Free Energy of Confined Nanoparticles
    • Authors: Nanhua Wu; Xiaoyan Ji, Rong An, Chang Liu, Xiaohua Lu
      Abstract: The nanoparticles generally show abnormal properties compared to those in the bulk phase, and they exhibit significant potential in various applications such as catalysis and energy conversion. However, the theoretical work for describing the properties of nanoparticles is limited with poor prediction capacity. In this work, the Gibbs free energy was studied, from both macroscope and microscope, predictive models were proposed to study the thermodynamic properties of nanoparticles with a generalized description of the Gibbs free energy considering the effects of surface-energy and the substrate contacted. The proposed model from the microscope was based on the corresponding states theory to describe the effect of the substrate on the Gibbs free energy of nanoparticles, in which the molecular parameter with a generalized constant was obtained from the melting point of metals due to sufficient experimental information. The comparison with the new measured experimental results proves the reliability of the model prediction. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T10:41:50.101726-05:
      DOI: 10.1002/aic.15861
       
  • Flame Stabilization in a Planar Micro-Combustor Partially Filled with
           Anisotropic Porous Medium
    • Authors: Long Meng; Jun Li, Qingqing Li, Junrui Shi
      Abstract: Heat recirculation through the combustor walls is responsible in sustaining flames in micro-combustors. Incorporating porous medium into micro-combustors helps further enhance heat recirculation via the solid matrix. However, the problem of anisotropy arises when the pore size is comparable to the characteristic length of micro-combustors. To quantitatively address the problem, an experimental study on the flame stability limits of premixed H2/air in a planar micro-combustor partially filled with porous medium is undertaken. Three folding schemes, namely, parallel sheets, streamwise flow passage and streamwise flow blocking, are employed to realize the anisotropic properties. By varying the width (W) and position (Lout) of the porous medium, the effects of folding schemes on the critical flashback (Ф2) and breaking-through (Ф3) conditions are examined. The experimental results indicate that the disturbance to flow velocity in the transverse direction mainly influences Ф2, while Ф3 is greatly affected by the blocking normal to the flow direction. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T10:41:19.263964-05:
      DOI: 10.1002/aic.15862
       
  • Pressure drop and saturation of non-wettable coalescing filters at
           different loading rates
    • Authors: Cheng Chang; Zhongli Ji, Jialin Liu
      Abstract: The effect of layers on the pressure drop and saturation of non-wettable filters at different loading rates were investigated. It was found that both the jump and channel pressure drop depended on the loading rate. The total channel pressure drop of different filters seemed independent of the number of layers. At the same loading rate, more layers led to fewer channels per layer and larger size of each channel. Moreover, according to the evolution of channel number and size, there was a reorganization of channel structure in the filters. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T10:41:12.627436-05:
      DOI: 10.1002/aic.15863
       
  • Oil Jet with Dispersant: Macro-Scale Hydrodynamics and Tip Streaming
    • Authors: Lin Zhao; Feng Gao, Michel C. Boufadel, Thomas King, Brian Robinson, Robyn Conmy, Kenneth Lee
      Abstract: Modeling the movement of oil released underwater is a challenging task due to limitations in measuring hydrodynamics in an oil-water system. In this work, we conducted an experiment of horizontal release of oil without and with dispersant. The model VDROP-J was used and compared to the model JETLAG, a miscible plume trajectory model. Both models were found to reproduce the oil jet hydrodynamics for oil without and with dispersant. The predicted DSD from VDROP-J matched closely observation for untreated oil. For oil with dispersant, experimental results have shown evidence that tip streaming occurred. For this purpose, a new conceptual module was developed in VDROP-J to capture the tip streaming phenomenon and an excellent match was achieved with observation. This study is the first to report tip streaming occurring in underwater oil jets, which should have consequences on predicting the DSD when dispersant are used on an underwater oil release. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T10:41:07.214771-05:
      DOI: 10.1002/aic.15864
       
  • Development of 3D Polymer DFT and Its Application to Molecular Transport
           through a Surfactant-Covered Interface
    • Authors: Yu Liu; Honglai Liu
      Abstract: We have developed a 3-dimensional polymer density functional theory (DFT) and applied it to predict the thermodynamic and structural information of molecular transport through a surfactant-covered interface. The Green recursive function (GRF) method has been employed to consider the chain conformation effect. The reference ideal gas (RIG) method has been developed, extending it from molecular DFT to polymer DFT, with a universal form to calculate thermodynamic properties such as the grand potential and free energy. We have demonstrated the accuracy of the theory by comparing it to available simulations. Furthermore, we have applied the theory to predict the free energy barrier and density profile of molecular transport through a surfactant-covered interface. The free energy profile provides reasonable predictions of the transition velocity, while the density profile gives insight into the microstructural information of the transport process, which is consistent with the available molecular simulations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T10:36:38.44232-05:0
      DOI: 10.1002/aic.15858
       
  • Spontaneous Imbibition of Liquid in Glass fiber Wicks, Part II: Validation
           of a Diffuse-front Model
    • Authors: M. Amin F. Zarandi; Krishna M Pillai
      Abstract: In Part I 1, we proposed a model based on sharp liquid-front where a good match with the experimental data was achieved. However the model failed to account for partial saturations in the wicks. Here we try Richard's equation to predict liquid saturation where the equation is solved numerically in 3-D using COMSOL and analytically in 1-D using Mathematica for glass-fiber wicks after treating them as transversely-isotropic porous media. As a novel contribution, relative permeability and capillary pressure are determined directly from pore-scale simulations in wick microstructure using the state-of-the-art software GeoDict. The saturation along the wick length is determined experimentally through a new liquid-N2 based freezing technique. After including the gravity effect, good agreements between the numerical/analytical predictions and experimental results are achieved in saturation distributions. We also validated the Richard's equation based model while predicting absorbed liquid-mass into the wick as function of time. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T10:36:00.867287-05:
      DOI: 10.1002/aic.15856
       
  • Multi-criteria optimization for parametrization of SAFT-type equations of
           state for water
    • Authors: Esther Forte; Jakob Burger, Kai Langenbach, Michael Bortz, Hans Hasse
      Abstract: Finding appropriate parameter sets for a given equation of state to describe different properties of a certain substance is an optimization problem with conflicting objectives. Such problem is commonly addressed by single-criteria optimization in which the different objectives are lumped into a single goal function. We show how multi-criteria optimization (MCO) can be beneficially used for parameterizing equations of state. The Pareto set which comprises a set of optimal solutions of the multi-criteria optimization problem is determined. As an example, the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) is used and applied to the description of the thermodynamic properties of water, focusing on saturated liquid density and vapor pressure. Different options to describe the molecular nature of water by the PC-SAFT EoS are studied and for all variants, the Pareto sets are determined, enabling a comprehensive assessment. When compared to literature models, Pareto optimization yields improved models. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-10T10:35:28.012935-05:
      DOI: 10.1002/aic.15857
       
  • A Mechanistic Modeling Framework for Gas-Phase Adsorption Kinetics and
           Fixed-Bed Transport
    • Authors: Austin P. Ladshaw; Sotira Yiacoumi, Ronghong Lin, Yue Nan, Lawrence L. Tavlarides, Costas Tsouris
      Abstract: Adsorption is a complex physicochemical process involving interparticle transport, interphase mass-transfer, intraparticle diffusion, and surface reactions. Although the exact description of the adsorption process will inevitably vary from system to system, it will always be governed by those primary mechanisms. Therefore, by devising a model framework that can inherently include those mechanisms, it would be possible to create a modeling platform on which many different adsorption problems could be solved numerically. To accomplish this task, a generalized 1-D conservation law model was created to include the necessary mechanisms of adsorption on several different geometrical domains. Specific model applications for adsorption were developed under that framework and validated using experimental data available in literature or obtained in this work. This modeling platform makes it easier to model various adsorption problems and develop new adsorption models because of the common treatment of the mathematics governing the physical processes. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-06T00:25:30.230112-05:
      DOI: 10.1002/aic.15855
       
  • Magnetic Particle Tracking for non-spherical particles in a cylindrical
           fluidized bed
    • Authors: K.A. Buist; P. Jayaprakash, N.G. Deen, J.T. Padding, J.A.M. Kuipers
      Abstract: In granular flow operations often particles are non-spherical. This has inspired a vast amount of research in understanding the behaviour of these particles. Various models are being developed to study the hydrodynamics involving non-spherical particles. Experiments however are often limited to obtain data on the translational motion only. This paper focusses on the unique capability of Magnetic Particle Tracking to track the orientation of a marker in a full 3D cylindrical fluidized bed. Stainless steel particles with the same volume and different aspect ratios are fluidized at a range of superficial gas velocities. Spherical and rod-like particles show distinctly different fluidization behaviour. Also the distribution of angles for rod-like particles changes with position in the fluidized bed as well as with the superficial velocity. Magnetic Particle Tracking shows its unique capability to study both spatial distribution and orientation of the particles allowing more in depth validation of Discrete Particle Models. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-06T00:25:24.925116-05:
      DOI: 10.1002/aic.15854
       
  • Issue information
    • Abstract: Cover illustration. Mass transfer parameter evaluation of absorption and distillation column packings, a cloud of methods and physical concepts. Image courtesy: John Roesler and Pascal Alix, IFP Energies Nouvelles.10.1002/aic.15737
      PubDate: 2017-07-03T12:29:02.378333-05:
      DOI: 10.1002/aic.15477
       
  • Optimization and control of bio-conversion of polymeric substrate in the
           chemostat
    • Authors: J-A. Sepulchre; F. Mairet, J-L. Gouzé
      Abstract: In this paper, a simple model of the growth of polymer-decomposing bacteria in a continuous stirred tank reactor is proposed. The dilution rate is controlled to optimize the output of monomers. This model is studied in order to find the optimum at the stationary state. However, the optimal stationary state is not robust against perturbations, leading to washout in the bioreactor. A control that makes the closed system globally stable around the optimal equilibrium is proposed. Then, a more complex model for polymers and oligomers of any lengths is studied. It is shown that the same technics also lead to a globally stable optimal point for the controlled system. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-01T02:35:37.297214-05:
      DOI: 10.1002/aic.15853
       
  • Adsorptive Removal of Refractory Sulphur Compounds by Tantalum Oxide
           Modified Activated Carbons
    • Authors: Amir A Iravani; Kamalakar Gunda, Flora T.T. Ng
      Abstract: Adsorptive desulphurization of a model diesel fuel consisting of dibenzothiophene (DBT) or 4,6-dimethyldibenzothiophene(4,6-DMDBT) in hexadecane was carried out over activated carbons and tantalum oxide modified (Ta-x/ACC, x= 2, 5 or 10wt% Ta, Activated Carbon Centaur) activated carbons at 50 °C. The adsorption isotherm for ACC followed the Langmuir model while the adsorption on Ta-5/ACC fitted the Sips equation indicating more than one type of adsorption sites. Characterization studies indicated new types of adsorption site resulting from the incorporation of Ta oxide into the porous structure of the ACC. XPS data suggested interaction of Ta with the S atom in DBT. The heats of adsorption in the liquid phase determined from micro flow calorimetry for DBT in C16 confirmed the interaction of Ta with DBT. Ta-5/ACC exhibited the highest adsorption capacity for 4,6-DMDBT compared to literature reports. Competitive adsorption experiments showed the adsorption capacity as follows: quinoline> DBT≫ naphthalene. This article is protected by copyright. All rights reserved.
      PubDate: 2017-07-01T02:35:35.526519-05:
      DOI: 10.1002/aic.15852
       
  • How penultimate monomer unit effects and initiator influence ICAR ATRP of
           n-butyl acrylate and methyl methacrylate
    • Authors: Stijn K. Fierens; Paul H. M. Van Steenberge, Marie-Françoise Reyniers, Dagmar R. D'hooge, Guy B. Marin
      Abstract: The relevance of penultimate monomer unit (PMU) effects and the selection of the correct initiator species under typical reversible deactivation radical copolymerization conditions is illustrated, using matrix-based kinetic Monte Carlo simulations allowing the visualization of all monomer sequences along individual chains. Initiators for continuous activator regeneration atom transfer radical polymerization (ICAR ATRP) is selected as illustrative polymerization technique with n-butyl acrylate and methyl methacrylate as comonomers, aiming at the synthesis of well-defined gradient copolymers. Using literature based model parameters, in particular temperature dependent monomer and radical reactivity ratios, it is demonstrated that PMU effects on propagation and ATRP (de)activation cannot be ignored to identify the most suited ICAR ATRP reactants (e.g. tertiary ATRP initiator) and reaction conditions (e.g. feeding rates under fed-batch conditions). The formulated insights highlight the need for further research on PMU effects on all reaction steps in radical polymerization. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-29T13:20:35.544449-05:
      DOI: 10.1002/aic.15851
       
  • Assessment of Kinetics of Photoinduced Fe-based Atom Transfer Radical
           Polymerization under Conditions Using Modeling Approach
    • Authors: Zhou Yin-Ning; Luo Zheng-Hong
      Abstract: Kinetic insight into photoinduced Fe-based atom transfer radical polymerization (ATRP) involving monomer-mediated photoreduction was carried out by modeling approach for the first time. Preliminary numerical analysis of number-average molar mass (Mn) derivation in this specific system was given. Simulation results provide a full picture of reactant concentration and reaction rate throughout the entire polymerization. Methyl 2,3-dibromoisobutyrate (MibBr2) generated from methyl methacrylate (MMA)-mediated photoreduction as the leading factor for the deviation of Mn from theoretical value was confirmed by reaction contributions in α-bromophenylacetate (EBPA) containing system. Reasonable predictions were made with respect to the polymerizations under a variety of initial conditions. Results show that increasing light intensity will shorten transition period and increase steady state polymerization rate; decreasing catalyst loading will cause the decrease in polymerization rate and Mn deviation; varying initiation activity will slightly increase the time to attain steady state of dispersity (Mw/Mn) evolution and enormously change the fraction of reaction contributions; increasing targeted chain length will extend transition period, decrease steady state polymerization rate, increase Mn deviation degree with same reaction contributions, and decrease the time to attain the steady state of Mw/Mn. The numerical analysis presented in this work clearly demonstrates the unique ability of our modeling approach in describing the kinetics of photoinduced Fe-based ATRP of MMA. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-29T13:20:23.651277-05:
      DOI: 10.1002/aic.15850
       
  • Enhancing Oxygen Permeation via Multiple Types of Oxygen Transport Paths
           in Hepta-bore Perovskite Hollow Fibers
    • Authors: Jiawei Zhu; Tianlei Wang, Zhe Song, Zhengkun Liu, Guangru Zhang, Wanqin Jin
      Abstract: The multiple types of efficient oxygen transport paths were demonstrated in high-mechanical-strength hepta-bore Ba0.5Sr0.5Co0.8Fe0.2O3-δ hollow fiber membranes. These types of paths play a prominent role in enhancing oxygen permeation fluxes (17.6 mL min−1 cm−2 at 1223 K) which greatly transcend the performance of state-of-the-art Ba0.5Sr0.5Co0.8Fe0.2O3-δ hollow fiber membranes, showing a good commercialization prospect. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-28T10:55:20.810451-05:
      DOI: 10.1002/aic.15849
       
  • Dehydrogenation Kinetic Model of Heavy Paraffins
    • Authors: Hongbo Jiang; Yilong Zhou, Liqun Zhou, Yu Wang, Jing Cao
      Abstract: Based on the dehydrogenation mechanism of heavy paraffins under industrial conditions, the intrinsic reaction kinetic model and catalyst deactivation model were established considering the influence of side reactions with different carbon-number heavy paraffins. Based on the experimental data of dehydrogenation reactions with different carbon-number paraffins in an axial continuous-flow isothermal fixed-bed microreactor, Powell optimization method was used to estimate the model parameters. The results show that there is a liner relationship between the activation energies and pre-exponential factors of homologous reactions and carbon number of paraffins. And a correlation model about the deactivation rate constants under different conditions was established. The validation of kinetic model showed that the model could be used to predict detailed product distribution with different feedstocks under different reaction conditions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-26T06:52:44.285205-05:
      DOI: 10.1002/aic.15848
       
  • Interface-Resolved Simulations of Normal Collisions of Spheres on a Wet
           Surface
    • Authors: Y. (Yali) Tang; B. (Britta) Buck, S. (Stefan) Heinrich, N.G. (Niels) Deen, J.A.M. (Hans) Kuipers
      Abstract: Detailed knowledge of micro-mechanics of individual particle collisions in the presence of liquid is crucial for modelling/understanding of wet granular flows that are omnipresent in nature and industrial applications. Despite many reported studies, very limited detailed interface-resolved modelling of such collision problems has been conducted. This paper presents an improved model for direct numerical simulations of normal impacts of spheres on wet surfaces. This model combines the immersed boundary method and the volume-of-fluid method supplemented with a model describing gas-liquid-solid contact line. It is demonstrated that our model not only correctly describes the collision dynamics of wet particles, but also well captures the dynamics of the liquid bridge formed during the collision. Quantitative agreement is obtained between the simulation results and the experimental data. It is concluded that the developed model constitutes a powerful tool to complement experimental studies, which are challenging for more complex wet collision systems in practice. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-26T06:52:42.349078-05:
      DOI: 10.1002/aic.15847
       
  • Rapid Development of Thickness-controllable Superamphiphobic Coating on
           the Inner Wall of Long Narrow Pipes
    • Authors: Ziyi Hu; Huaiyuan Wang, Yixing Zhu, Yanji Zhu
      Abstract: A novel electrochemical technique had been introduced to prepare nanocrystalline superamphiphobic coatings inside of narrow pipes of significant length. The axially propagated ultrasound was utilized to ensure the scaling-up potential of this technique. The coating had strong mechanical strength, durability in low/high pH solutions and the potential of controlling its thickness while preserving a stable nonwetting performance. In addition, the properties of anti-scaling and drag reduction under the flowing circumstance had been demonstrated. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-23T20:55:32.779806-05:
      DOI: 10.1002/aic.15843
       
  • Feasible Separation Regions for Distillation II: A Generalized
           Distillation Limit
    • Authors: Lechoslaw J. Krolikowski
      Abstract: The boundary of the feasible separation region consists of several curves that are related to specific types of operating modes of the column. Some of these curves create a well-known product composition multitude, whereas other curves form a generalized distillation limit. The generalized distillation limit demarcates the sloppy splits (i.e., separations in which the composition of at least one product lies inside the composition space) from regions not accessible by distillation and depends on the thermodynamic state of the feed (a mixture of vapor and liquid in equilibrium or saturated vapor/liquid) and column equipment (total/partial condenser and total/partial reboiler). The mathematical equations describing the generalized distillation limit are obtained based on the relationships between the curves (which form the generalized distillation limit) and specific types of operating modes of the column as well as the material balances for the enriching and stripping columns. Furthermore, the vapor and liquid pinch-point curves, which go through the feed composition point, are not dependent on the thermodynamic state of the feed and column equipment. In addition, an algorithm for determining the generalized distillation limit is obtained. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-23T20:50:40.765616-05:
      DOI: 10.1002/aic.15845
       
  • Universal Correlation for Gas Hydrates Suppression Temperature of
           Inhibited Systems: I. Single Salts
    • Authors: Yue Hu; Bo Ram Lee, Amadeu K. Sum
      Abstract: Reliable prediction of hydrate suppression temperature in presence of inhibitors, such as salts, over a wide range of pressures (up to 200 MPa) is critically important, especially in the area of deepwater oil and gas production. However, the existing models and correlations that account for salts have severe limitations and deficiencies in estimating the hydrate suppression temperature. Herein, we propose a new correlation, to be called Hu-Lee-Sum correlation, that significantly improves the predictions of the hydrate suppression temperature by considering the salt species and concentrations, system temperature and pressure, and hydrate structure. This paper represents part I of this work and it will detail the development of the correlation and demonstrate the generality and universality of the correlation to predict the hydrate suppression temperature for any single salt system. Specifically, we show accurate predictions for the hydrate suppression temperature for a number of chloride and bromide salt brine systems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-23T20:50:37.552754-05:
      DOI: 10.1002/aic.15846
       
  • Oxygen transfer in co-extruded multilayer active films for food packaging
    • Authors: Luciano Di Maio; Francesco Marra, Tesfaye F. Bedane, Sam Saguy, Loredana Incarnato
      Abstract: Oxygen scavenger applications in flexible food packaging are still limited due to the difficulty to ensure scavenging activity during storage and throughout the product shelf life. To avoid fast inactivation of the scavenger, multilayer active structures can be realized by inserting the active layer between two or more inert layers. In this work, an unsteady-state 1D reaction-diffusion mass transfer model was developed for predicting and optimizing the barrier-to-oxygen performance and the physical configurations of the co-extruded multilayer active films. The film configuration was a 3-layers structure composed of polyethylene terephthalate (PET) as external inert layers, and PET with a polymeric oxygen scavenger as the core reactive layer. Scavenging activity of the multilayer film increased with the reactive layer thickness. Oxygen absorption reaction at short times decreased proportionally with the thickness of the external layers. The most appropriate combinations of inert-to-active film thickness were studied and analyzed. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-23T20:45:30.529482-05:
      DOI: 10.1002/aic.15844
       
  • A Novel Route for Green Conversion of Cellulose to HMF by Cascading
           Enzymatic and Chemical Reactions
    • Authors: Yunlei Zhang; Yao Chen, Pei Jin, Meng Liu, Jianming Pan, Yongsheng Yan, Qingang Xiong
      Abstract: In this work, a novel route to deconstruct cellulose into 5-hydroxymethylfurfural (HMF) by cascading enzymatic and chemical reactions is reported. For biocatalyst preparation, Fe3O4 nanoparticles encapsulated SBA-15 with appropriate pore size was synthesized and utilized as magnetic scaffolds for the immobilization of cellulase. For chemical catalyst preparation, sulfated zirconium dioxide conformed monolayers were grafted on SBA-15 template to create thermally robust mesoporous catalysts with tunable solid basic/Lewis acid and Brønsted acid sites. Catalytic performance of biocatalyst and chemical catalyst was explored in the aqueous phase conversion of IL pre-treated cellulose to glucose, and in the iPrOH/water solvent conversion of glucose to HMF conversion, respectively. After the optimization of reaction conditions, a sequential conversion of pre-treated cellulose to glucose and glucose to HMF was carried out, and 43.6% HMF yield can be obtained. The cascaded enzymatic and chemocatalytic reaction system demonstrates an effective and economically friendly process for biomass energy conservation. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-22T18:35:46.710151-05:
      DOI: 10.1002/aic.15841
       
  • Modeling the Reaction Event History and Microstructure of Individual
           Species in Post-Polymerization Modification
    • Authors: Julio C. Hernández-Ortiz; Paul Van Steenberge, Jan N. E. Duchateau, Klaas Remerie, Carolina Toloza, Ana Luisa Vaz, Fons Schreurs, Marie-Françoise Reyniers, Guy B. Marin, Dagmar R. D'hooge
      Abstract: For post-polymerization modification, a novel kinetic Monte Carlo (kMC) modeling strategy for the description of the reaction event history and the evolution of the microstructure of individual macrospecies with a complex topology is presented. The kMC model allows the kinetic analysis of free radical induced grafting of vinyl monomers onto polyethylene (PE) chains, assuming isothermal conditions and perfect macromixing and accounting for diffusional limitations on the micro-scale. Not only average characteristics such as the monomer conversion, grafting selectivity and yield, but also the chain length distribution (CLD) of all macromolecular species types, the average “from/to” grafting and crosslinking density, the number of (dead) grafts and crosslinks per individual macromolecule, the chain length of every graft, and the CLD of the grafted chains are calculated. Under typical grafting conditions, depropagation and diffusional limitations cannot be ignored. The functionalization occurs mainly on those macrospecies in the PE-CLD with a high mass concentration. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-22T18:35:31.920707-05:
      DOI: 10.1002/aic.15842
       
  • Darcy's law for two-dimensional ows: Singularities at corners and a new
           class of models
    • Authors: Yulii D. Shikhmurzaev
      Abstract: As is known, Darcy's model for fluid flows in isotropic homogeneous porous media gives rise to singularities in the velocity field for essentially two-dimensional flow configuration, like flows over corners. Considering this problem from the modelling viewpoint, the present study aims at removing this singularity, which cannot be regularized via conventional generalizations of the Darcy model, like Brinkman's equation, without sacrificing Darcy's law itself for unidirectional flows where its validity is well established experimentally. The key idea is that, as confirmed by a simple analogy, the permeability of a porous matrix with respect to flow is not a constant independent of the flow but a function of the flow field (its scalar invariants), decreasing as the curvature of the streamlines increases. This introduces a completely new class of models where the flow field and the permeability field are linked and, in particular problems, have to be found simultaneously. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-22T18:12:50.506215-05:
      DOI: 10.1002/aic.15840
       
  • Feasible Separation Regions for Distillation I: Structure
    • Authors: Lechoslaw J. Krolikowski
      Abstract: A feasible separation region is determined for only four special combinations of a saturated vapor/liquid feed and total/partial condenser or reboiler. The present work addresses the construction of a feasible separation region for a general case where the feed is a mixture of vapor and liquid in equilibrium and where the column is equipped with a partial/total condenser and reboiler. The analysis reveals that the product composition sets (which are defined for various reflux and reboil ratios and a fixed number of stages in each column section) are the main elements of the feasible separation region. The application of the geometric model of the column in combination with the shape of the distillation line led to the conclusion that the feasible separation region is the union of two product composition sets for both enriching and stripping columns both with an infinite number of stages. The boundary of the feasible separation region consists of several curves related to specific types of operating modes in the column. Some of these curves create a well-known product composition multitude, whereas other curves form a generalized distillation limit. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-19T10:31:02.506929-05:
      DOI: 10.1002/aic.15839
       
  • Structure and Catalytic Consequence of Mg-modified VOx/Al2O3 Catalysts for
           Propane Dehydrogenation
    • Authors: Tengfang Wu; Gang Liu, Liang Zeng, Guodong Sun, Sai Chen, Rentao Mu, Sika Agbotse Gbonfoun, Zhi-Jian Zhao, Jinlong Gong
      Abstract: Supported VOx catalysts are promising non-oxidative propane dehydrogenation (PDH) materials for their commercially attractive activity and propylene selectivity. However, they frequently suffer from rapid deactivation caused by coke deposition. This paper describes the promoting role of magnesium on the stability of VOx/Al2O3 catalysts for PDH. A series of VOx/Al2O3 and Mg-modified VOx/Al2O3 catalysts were synthesized by an incipient wetness impregnation method. The catalysts were carefully characterized by Raman spectra, UV-Vis spectra, STEM, TGA and in situ DRIFTS. We showed that the stability of a 12V/Al2O3 catalyst was significantly improved upon addition of small amounts of MgO. Experimental evidences indicate that V2O5 nanoparticles emerge in the 12V/Al2O3 samples, and appropriate Mg addition helps dispersing the V2O5 nanoparticles into 2D VOx species thus decreasing coke formation and improving stability in non-oxidative dehydrogenation of propane. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-16T11:20:52.05908-05:0
      DOI: 10.1002/aic.15836
       
  • A Highly Stable Metal-Organic Framework with Optimum Aperture Size for CO2
           Capture
    • Authors: Zhigang Hu; Yuxiang Wang, Shamsuzzaman Farooq, Dan Zhao
      Abstract: We herein report an optimal modulated hydrothermal (MHT) synthesis of a highly-stable zirconium metal-organic framework (MOF) with an optimum aperture size of 3.93 Å that is favorable for CO2 adsorption. It exhibits excellent CO2 uptake capacities of 2.50 and 5.63 mmol g−1 under 0.15 bar and 1 bar at 298 K, respectively, which are among the highest of all the pristine water-stable MOFs reported so far. In addition, we have designed a lab-scale breakthrough set-up to study its CO2 capture performance under both dry and wet conditions. The velocity at the exit of breakthrough column for mass balance accuracy is carefully measured using argon with a fixed flow rate as the internal reference. Other factors that may affect the breakthrough dynamics, such as pressure drop and its impact on the roll-up of the weaker component have been studied in details. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-16T11:20:50.948084-05:
      DOI: 10.1002/aic.15837
       
  • A framework for ammonia supply chain optimization incorporating
           conventional and renewable generation
    • Authors: Andrew Allman; Douglas Tiffany, Stephen Kelley, Prodromos Daoutidis
      Abstract: Ammonia is an essential nutrient for global food production brought to farmers by a well established supply chain. This paper introduces a supply chain optimization framework which incorporates new renewable ammonia plants which produce hydrogen from wind-powered electrolysis into the conventional ammonia supply chain. Both economic and environmental objectives are considered. The framework is then applied to two separate case studies analyzing the supply chains of Minnesota and Iowa, respectively. The base case results present an expected tradeoff between cost, which favors purchasing ammonia from conventional plants, and emissions, which favor building distributed renewable ammonia plants. Further analysis of this tradeoff shows that a carbon tax above $25/t will reduce emissions in the optimal supply chain through building large renewable plants. The importance of scale is emphasized through a Monte Carlo sensitivity analysis, as the largest scale renewable plants are selected most often in the optimal supply chain. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-16T11:20:23.663565-05:
      DOI: 10.1002/aic.15838
       
  • Advice for Emerging Researchers on Research Program Development: A
           Personal Case Study
    • Authors: Christopher W. Jones
      PubDate: 2017-06-15T17:15:30.012427-05:
      DOI: 10.1002/aic.15835
       
  • How Nano-Scale Roughness Impacts the Flow of Grains influenced by
           Capillary Cohesion
    • Authors: Casey Q. LaMarche; Andrew W. Miller, Peiyuan Liu, Stuart Leadley, Christine M. Hrenya
      Abstract: We show that nano-scale changes in surface roughness affect the macro-scale (many-particle) behavior of granular materials influenced by cohesion. Macro-scale effects of roughness are investigated for conditions where cohesion is dominated by either humidity-induced or van der Waals-induced forces. Surface-topography measurements are used to calculate the relevant inter-particle cohesive forces. The (force-dominated) macro-scale cohesion measurements are explained via the ratio of the predicted inter-particle cohesive force to gravity, thus reinforcing the importance of roughness to cohesion. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-13T10:46:24.016806-05:
      DOI: 10.1002/aic.15830
       
  • Integrating the Physics with Data Analytics for the Hybrid Modelling of
           the Granulation Process
    • Authors: Wafa' H. AlAlaween; Mahdi Mahfouf, Agba D. Salman
      Abstract: A hybrid model based on physical and data interpretations to investigate the high shear granulation (HSG) process is proposed. This model integrates three separate component models, namely, a computational fluid dynamics model, a population balance model and a radial basis function model, through an iterative procedure. The proposed hybrid model is shown to provide the required understanding of the HSG process, and to also accurately predict the properties of the granules. Furthermore, a new fusion model based on integrating fuzzy logic theory and the Dempster-Shafer theory is also developed. The motivation for such a new modelling framework stems from the fact that integrating predictions from models which are elicited using different paradigms can lead to a more robust and accurate topology. As a result, significant improvements in prediction performance have been achieved by applying the proposed framework when compared to single models. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-13T10:46:22.984935-05:
      DOI: 10.1002/aic.15831
       
  • An Efficient and Reliable Predictive Method for Fluidized Bed Simulation
    • Authors: Liqiang Lu; Tingwen Li, Sofiane Benyahia
      Abstract: In past decades, the continuum approach was the only practical technique to simulate large-scale fluidized bed reactors because discrete approaches suffer from the cost of tracking huge numbers of particles and their collisions. This study significantly improved the computation speed of discrete particle methods in two steps: First, the time-driven hard-sphere (TDHS) algorithm with a larger time-step is proposed allowing a speedup of 20-60 times; second, the number of tracked particles is reduced by adopting the coarse-graining technique gaining an additional 2-3 orders of magnitude speedup of the simulations. A new velocity correction term was introduced and validated in TDHS to solve the over-packing issue in dense granular flow. The TDHS was then coupled with the coarse-graining technique to simulate a pilot-scale riser. The simulation results compared well with experiment data and proved that this new approach can be used for efficient and reliable simulations of large-scale fluidized bed systems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-13T10:46:20.017741-05:
      DOI: 10.1002/aic.15832
       
  • The Development of Kinetics Model for CO2 Absorption into Tertiary Amines
           containing Carbonic Anhydrase
    • Authors: Bin Liu; Xiao Luo, Zhiwu Liang, Wilfred Olson, Helei Liu, Raphael Idem, Paitoon Tontiwachwuthikul
      Abstract: CO2 absorption into aqueous solutions of two tertiary alkanolamines, namely, MDEA and DMEA with and without carbonic anhydrase (CA) was investigated with the use of the stopped-flow technique at temperatures in the range of 293-313 K, CA concentration varying from 0-100 g/m3 in aqueous MDEA solution with the amine concentration ranging from 0.1-0.5 kmol/m3, and CA concentration varying from 0-40 g/m3 in aqueous DMEA solution with the amine concentration ranging from 0.05-0.25 kmol/m3. The results show that the pseudo first-order reaction rate (k0, amine; s−1) is significantly enhanced in the presence of CA as compared with that without CA. The enhanced values of the kinetic constant in the presence of CA has been calculated and a new kinetics model for reaction of CO2 absorption into aqueous tertiary alkanolamine solutions catalyzed by CA has been established and used to make comparisons of experimental and calculated pseudo first-order reaction rate constant (k0, with CA) in CO2-MDEA-H2O and CO2-DMEA-H2O solutions. The AADs were 15.21% and 15.17% respectively. The effect of pKa on the CA activities has also been studied by comparison of CA activities in different tertiary amine solutions, namely, TEA, MDEA, DMEA and DEEA. The pKa trend for amines were: DEEA>DMEA>MDEA>TEA. In contrast the catalyst enhancement in amines was in the order: TEA> MDEA> DMEA> DEEA. Therefore, it can be seen that the catalyst enhancement in the amines decreased with their increasing pKa values. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-13T10:46:15.564291-05:
      DOI: 10.1002/aic.15833
       
  • Self-Similar Breakup of Viscoelastic Thread for Droplet Formation in
           Flow-Focusing Devices
    • Authors: Wei Du; Taotao Fu, Qindan Zhang, Chunying Zhu, Youguang Ma, Huai Z. Li
      Abstract: The self-similarity of the breakup of viscoelastic dispersed thread for droplet formation in flow-focusing devices is investigated experimentally. A high-speed camera is used to capture the evolution and angles of the cone-shaped liquid-liquid interface. The self-similar profiles for the liquid-liquid interface are obtained by normalizing the interface with the minimum width of the dispersed thread. The breakup of the dispersed thread transfers from a self-similar power law scaling stage with an exponent of 0.36 to a self-similar exponential scaling stage. The asymptotic cone angles prior to final breakup are consistent with the value of 125.5° and 151°, respectively. The viscoelasticity inhibits the development of finite-time singularity for the breakup of the liquid-liquid interface at microscale, similar to the capillary breakup at macroscale. The results demonstrate that the breakup of the viscoelastic dispersed thread for droplet formation exhibits self-similarity at microscale. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-13T10:46:10.038121-05:
      DOI: 10.1002/aic.15834
       
  • Investigation of Hydrodynamics in Bubble Column with Internals using
           Radioactive Particle Tracking (RPT)
    • Authors: Dinesh V. Kalaga; H.J. Pant, Sameer V. Dalvi, Jyeshtharaj B. Joshi, Shantanu Roy
      Abstract: Even though many experimental investigations are reported on this subject of liquid velocity patterns in bubble columns, most of the reported work is restricted to measurements at the near wall regions, columns without internals, and in low dispersed phase holdups. In the present work, a non-invasive Radioactive Particle Tracking (RPT) technique was employed to quantify the hydrodynamic parameters in 120 mm diameter bubble column with, and without vertical rod internals, using air/water system as the working fluids. The superficial air velocities cover a wide range of flow regimes: from 14 mm/s to 265 mm/s. Experiments were performed for four internals configurations with percentage obstruction area varied from 0 (without internals) to 11.7%. We report that the liquid phase hydrodynamics depends strongly on superficial gas velocity and internals. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-12T11:01:25.58851-05:0
      DOI: 10.1002/aic.15829
       
  • Prediction of thermodynamic properties of aqueous electrolyte solutions
           using equation of state
    • Authors: Reza Shahriari; Mohammad Reza Dehghani
      Abstract: In this study, a predictive model is presented for estimation of second order thermodynamic properties of electrolyte solutions. In order to provide a comprehensive understanding, the capability of modified electrolyte PC-SAFT up to high pressure and temperature has been studied. In addition to the first order derivative thermodynamic properties, the Gibbs free energy, enthalpy and heat capacity of aqueous electrolyte solutions at infinite dilution are predicted. Using new methodology, the dielectric constant is modified to keep the pressure, temperature and ionic strength dependency. Our results show that the Born term has a significant contribution on prediction of second order derivative properties. Meanwhile the impact of temperature-dependent solution dielectric constant on standard state heat capacity is studied. Finally, the isobaric heat capacity at various salt concentrations is predicted without any adjustable parameters. The results of this work indicate an acceptable agreement with experimental data especially at high pressure and temperature. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-09T06:33:48.954317-05:
      DOI: 10.1002/aic.15827
       
  • On Air Entrainment in a Water pool by Impingement of a Jet
    • Authors: Vatsal Sanjay; Arup Kumar Das
      Abstract: Air entrainment due to impingement of a water jet on a pool is studied extensively to understand the physics of the initiation and the cluster of bubbles formed below the free surface. Possible outcomes due to the jet impingement in a pool have been identified as smooth free surface without entrainment or formation of rigorous bubble cluster below the jet-pool contact. Triangular entrained region is found to be a three-dimensional association of disconnected bubble population continuously breaking and making with the neighbors. A correlation for prediction of maximum entrained height for a range of jet diameters and lengths is proposed. The trajectory of a single bubble is also studied to understand the kinematics of the bubble cluster. Alongside, an electrical conductivity probe has been used to examine the probabilistic presence of the bubble at a given depth in the liquid pool. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-08T22:21:54.436622-05:
      DOI: 10.1002/aic.15828
       
  • Comment on Xu et al. 2017
    • Authors: Christopher J. Landry; Maša Prodanović, Peter Eichhubl
      PubDate: 2017-06-08T21:40:44.879544-05:
      DOI: 10.1002/aic.15823
       
  • Inhomogeneous distribution of platinum and ionomer in the porous cathode
           to maximize the performance of a PEM fuel cell
    • Authors: Lei Xing; Prodip K. Das, Keith Scott, Weidong Shi
      Abstract: A proton exchange membrane (PEM) fuel cell model, accounting for the combined water transport mechanism, ionomer swelling, water phase-transfer, two-phase flow and transport processes, is developed. The inhomogeneous distributions of Pt and ionomer inside the catalyst layer (CL) are numerically studied to achieve an optimal cell performance for two types of oxygen reduction reaction catalysts at different loadings. Results indicate that the optimal variation in loading through the thickness of the electrode (slopes) of Pt catalyst and ionomer vary with conditions of operation. An optimal platinum slope increases the agglomerate effectiveness factor and decreases the second Damköhler number near the CL-membrane interface. An optimal ionomer slope increases the CL porosity near the GDL-CL interface and decreases the mass transport resistance of reactant through the ionomer film. Their interaction shows that the optimal platinum slope is a tradeoff between the electrochemical active surface area and porosity at high current densities. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-07T10:35:47.39902-05:0
      DOI: 10.1002/aic.15826
       
  • The effect of the size of square microchannels on hydrodynamics and mass
           transfer during liquid-liquid slug flow
    • Authors: Mehdi Sattari-Najafabadi; Mohsen Nasr Esfahany, Zan Wu, Bengt Sundén
      Abstract: The present study investigated the influence of square microchannel size on hydrodynamics and mass transfer in the liquid-liquid slug flow regime. Three square microchannels with the hydraulic diameters of 200, 400 and 600 µm were used. The employed method for estimating mass transfer coefficients remarkably increased the accuracy of the results. The findings revealed that decreasing the microchannel size improved the interfacial area due to plug length enlargement and deteriorated mass transfer resistances because of augmented internal circulations, leading to the considerable enhancement of mass transfer coefficients. The increasing effect on the overall mass transfer coefficient became greater with flow velocity, showing that size effect on mass transfer resistances was more profound at higher flow velocities. The influence of size on the interfacial area was significantly greater than that on mass transfer resistances due to the significant increment of wall film length with the decrease in channel size. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-07T10:35:43.204206-05:
      DOI: 10.1002/aic.15822
       
  • Coaxial Electrohydrodynamic Atomization towards Large Scale Production of
           Core-shell Structured Microparticles
    • Authors: Wei-Cheng Yan; Yen Wah Tong, Chi-Hwa Wang
      Abstract: In this work, a double-nozzle coaxial electrohydrodynamic atomization (CEHDA) system was designed as an instructive case towards large-scale production of core-shell microspheres. The effect of nozzle-to-nozzle distance was investigated to reveal that the interference between neighboring nozzles significantly affect the product quality in terms of morphology and core-shell structure. Optimal spacing indicated that ∼3000 nozzle/m2 packing density may be achieved with minimum interference of electric field from neighboring nozzle by adjusting the nozzle-to-nozzle distance greater than 0.018m. The proposed multi-scale model also showed that the X-component of electric field strength (Ex) at the region near side nozzles increases with increasing nozzle number, and the bending of jets/sprays at the side may be reduced by using dummy nozzle at the edge side. The model could guide the design of multi-nozzle CEHDA system for production of core-shell microparticles in large-scale. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-07T10:30:27.034469-05:
      DOI: 10.1002/aic.15821
       
  • Quantitative dependence of CH4-CO2 dispersion on immobile water fraction
    • Authors: Marco Zecca; Sarah J. Vogt, Abdolvahab Honari, Gongkui Xiao, Einar O. Fridjonsson, Eric F. May, Michael L. Johns
      Abstract: Enhanced Gas Recovery (EGR) involves CO2 injection into natural gas reservoirs to both increase gas recovery and trap CO2. EGR viability can be determined by reservoir simulations; however these require a description of fluid dispersion (mixing) between the supercritical CO2 and natural gas. Here we quantify this dispersivity (α) in sandstone rock plugs as a function of residual water fraction. To ensure the accuracy of such data, we designed a novel core flooding experimental protocol that ensured an even spatial distribution of water, minimised erroneous entry/exit contributions to mixing, and minimised dissolution of the CO2 into the water phase. Dispersivity was found to increase significantly with water content, although the differences in α between sandstones were eliminated upon the inclusion of residual water. This enabled development of a correlation between α and water content and, hence, between the dispersion coefficient and Peclet number that is readily incorporable into reservoir simulations. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-07T10:30:25.804003-05:
      DOI: 10.1002/aic.15824
       
  • Process Design and Control optimization: A simultaneous approach by
           multi-parametric programming
    • Authors: Nikolaos A. Diangelakis; Baris Burnak, Justin Katz, Efstratios N. Pistikopoulos
      Abstract: We present a framework for the application of design and control optimization via multiparametric programming through four case studies. We develop design dependent multi-parametric model predictive controllers that are able to provide the optimal control actions as functions of the system state and the design of the process at hand, via our recently introduced PAROC framework1. The process and the design dependent explicit controllers undergo a Mixed Integer Dynamic Optimization (MIDO) step for the determination of the optimal design. The result of the MIDO is the optimal design of the process under optimal operation. We demonstrate the framework through case studies of a tank, a continuously stirred tank reactor, a binary distillation column and a residential cogeneration unit. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-07T10:30:19.334695-05:
      DOI: 10.1002/aic.15825
       
  • Process Flow-Sheet Synthesis: Systems-Level Design applied to Synthetic
           Crude Production
    • Authors: James Alistair Fox; Diane Hildebrandt, David Glasser, Bilal Patel
      Abstract: This paper showcases a novel approach for conceptual design for process flow-sheets at the “systems-level”.A graphical technique, called the “GH-space”, is used to analyze the flows of material, heat and work within a process to provide insight into the interactions of various units within the process.Any unit process, which interacts with the surroundings by transferring heat and work, can be represented as a vector on the GH-space. While material and energy balances are normally performed on a flowsheet, this vectored approach allows the material and energy balances to be used to construct a flowsheet.This paper focuses on using the GH-space to synthesis a synthetic fuels flowsheet.It was shown that a process could be designed that not only produced the desired product but could also consume carbon dioxide as a feed, along with the feeds of methane and oxygen, and could even potentially generate electricity. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-06T01:05:36.912082-05:
      DOI: 10.1002/aic.15818
       
  • Heat Assisted Twin Screw Dry Granulation
    • Authors: Y. Liu; M. R. Thompson, K.P. O'Donnell, S. Ali
      Abstract: A new ‘assisted' dry granulation method has been devised for the twin-screw granulator. The method may be beneficial to drug preparation as it limits heat exposure to only one barrel zone, much shorter than melt granulation. Its mechanism was investigated using four placebo formulations, each containing a polymer binder with a glass transition temperature lower than 130°C. Variables of study included screw configuration, screw speed, barrel zone temperature and moisture content. Granulated samples were characterized for size and porosity while feed powders were examined for their thermal transitions, inter-particle friction, cohesion, and sintering rate. Results indicated that granule coalescence relied upon melting of polymer binder in the kneading blocks by a combination of heat conducted from barrel and generated from screw speed friction. Successful granulation was possible with minimal addition of water, though varying the moisture content showed the relevance of the polymer's glass transition temperature and sintering progress. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-05T10:56:39.411745-05:
      DOI: 10.1002/aic.15820
       
  • Transferable Potentials for Phase Equilibria. Improved United-Atom
           Description of Ethane and Ethylene
    • Authors: Mansi S. Shah; Michael Tsapatsis, J. Ilja Siepmann
      Abstract: A more accurate version of the Transferable Potentials for Phase Equilibria – United Atom force field, called TraPPE–UA2, for ethane and ethylene is presented. Very similar molecular volumes, shapes, and self- and cross-interaction strengths of ethane and ethylene make their separation fundamentally interesting and industrially challenging. Separation factors as low as 1.5–3.0 necessitate very accurate molecular models in order to be able to computationally design potential separation processes. Additional force field parameters, namely the distance between the Lennard-Jones sites for both compounds and partial charges only for ethylene, are introduced in the parameterization and different combining rules for the Lennard-Jones interaction are considered. In addition to the liquid densities and critical temperature, the training set also includes saturation vapor pressures to yield an accurate two-site ethane model. Binary ethane/ethylene, CO2/ethylene, and H2O/ethylene vapor–liquid equilibria and H2O/ethylene dimer calculations are used for further optimization of a four-site ethylene model. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-05T10:50:33.246746-05:
      DOI: 10.1002/aic.15816
       
  • Predicting Phase Behavior in Aqueous Systems without Fitting Binary
           Parameters II: Gases and Non-Aromatic Hydrocarbons
    • Authors: Ilya Polishuk; Helena Lubarsky, Dong NguyenHuynh
      Abstract: This investigation continues a series of studies evaluating the capability of the recently proposed CP-PC-SAFT and sPC-SAFT of Liang et al. to estimate the thermodynamic properties of aqueous systems in the entirely predictive manner. Similarly to the previously considered systems, CP-PC-SAFT remains a realistic estimator of the available data on critical loci, HTHP phase equilibria and volumetric properties also in the cases of non-polar gases and non-aromatic hydrocarbons from argon and nitrogen till n-eicosane and squalene while keeping zero values of binary parameters. Nevertheless, such application of the model poses certain unavoidable compromises on its accuracy. Inter alia, CP-PC-SAFT is a particularly inaccurate estimator of the water-rich liquid phases away from the critical points. sPC-SAFT predicts these data in a more reliable manner. Moreover, its predictive capability goes beyond the liquid phases and it exhibits a remarkable accuracy in forecasting various phase equilibria below the critical point of water. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-05T10:50:29.895255-05:
      DOI: 10.1002/aic.15815
       
  • Analysis of the Effect of Small Amounts of Liquid on Gas-Solid
           Fluidization using CFD-DEM Simulations
    • Authors: C. M. Boyce; A. Ozel, J. Kolehmainen, S. Sundaresan
      Abstract: Gas-solid fluidization involving small amounts of liquid is simulated using a CFD-DEM model. The model tracks the amount of liquid on each particle and wall element and incorporates finite rates of liquid transfer between particles and pendular liquid bridges which form between two particles as well as between a particle and a wall element. Viscous and capillary forces due to these bridges are modeled. Fluidization-defluidization curves show that minimum fluidization velocity and defluidized bed height increase with Bond number (Bo), the ratio of surface tension to gravitational forces, due to cohesion and inhomogeneous flow structures. Under fluidized conditions, hydrodynamics and liquid bridging behavior change dramatically with increasing Bo, and to a lesser extent with capillary number, the ratio of viscous to surface tension forces. Bed fluidity is kept relatively constant across wetting conditions when one maintains a constant ratio of superficial velocity to minimum fluidization velocity under wet conditions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-05T10:50:26.631774-05:
      DOI: 10.1002/aic.15819
       
  • A molecular-thermodynamic approach to predict the micellization of binary
           surfactant mixtures containing amino sulfonate amphoteric surfactant and
           nonionic surfactant
    • Authors: Zhao Hua Ren
      Abstract: A molecular-thermodynamic approach was adopted to predict the value of mixed critical micelle concentration (cmc) for the binary surfactant mixtures constituted by an amino sulfonate amphoteric surfactant, sodium 3-(N-dodecyl ethylenediamino)-2-hydropropyl sulfonate (abbr. C12AS), and a nonionic surfactant, octylphenol polyethylene ether (OP-n, where n denotes the average number of oxyethylene glycol ether). In this investigation, considering two positive charges on the hydrophilic group of C12AS, which is unlike to conventional zwitterionic surfactants having one positive charge (such as, alkylbetaine, etc.), three schemes were designed to obtain the geometric parameter describing the dipole structure of C12AS. According to the selected optimum scheme, four cases corresponding to the different conformations of both the headgroup and the hydrocarbon chain of surfactant were discussed. The results show that the predicted value of mixed cmc for the C12AS/OP-n mixtures agrees well with the experiment value. The deviation of the predicted value from the experimental value can be explained by the effect of the hydrophilicity of OP-n on the process of micellization. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-05T10:50:25.382569-05:
      DOI: 10.1002/aic.15817
       
  • Pipe Flow of a Dense Emulsion: Homogeneous Shear-Thinning or Shear-Induced
           Migration'
    • Authors: Micheline Abbas; Amélie Pouplin, Olivier Masbernat, Alain Liné, Sandrine Décarre
      Abstract: The flow field of a 70% concentrated non-colloidal o/w emulsion in a pipe has been investigated by means of PIV in a matched refractive index medium. At steady state and in laminar regime, the shape of axial velocity profiles is not parabolic and exhibits a shear-thinning behavior of the dense emulsion, with a flow index of 0.5 and a negligible yield stress (less than 1 Pa). However, instead of a square root law, the pressure drop increases linearly with Um. To explain this apparent inconsistency, two mechanisms of different nature are considered. The first originates from a possible relation between the consistency factor and the drop mean diameter. The second mechanism is shear-induced migration and leads to the development of a concentration gradient in the pipe cross-section. Both mechanisms considered reconcile the experimental data, the apparent local shear-thinning behavior and the linear evolution of the pressure drop with the flowrate. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T08:05:43.559059-05:
      DOI: 10.1002/aic.15811
       
  • How graphical analysis helps interpreting optimal experimental designs for
           nonlinear enzyme kinetic models
    • Authors: Rüdiger Ohs; Jan Wendlandt, Antje C. Spiess
      Abstract: Progress curve experiments combined with optimal experimental design (OED) are an efficient approach to determine enzyme kinetics. However, it is hardly possible to verify why specific experiments are suggested for nonlinear enzyme kinetic model identification. Therefore, we systematically investigated the surface and contour plots of the sensitivities and of the OED criteria which are based on sensitivities. The model reaction was an enzyme catalyzed self-ligation of aldehydes to chiral 2-hydroxyketones. The visualization improved the understanding of OED and allowed for deducing and confirming five suggestions for kinetic identification: 1. Avoid experiments vicinal to the reaction equilibrium, 2. Choose the design space as large as possible, 3. Prefer D(eterminant)- and E(igenvalue)-criteria over the A(verage)-criterion, 4. Apply enzyme concentrations such that the reaction does not complete too fast, and 5. Few optimal experiments result in significantly improved parameter estimations. The graphical analysis also provides information about selecting appropriate optimization algorithms. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T07:20:55.076931-05:
      DOI: 10.1002/aic.15814
       
  • Prediction of Maximum Recoverable Mechanical Energy via Work Integration:
           A Thermodynamic Modeling and Analysis Approach
    • Authors: Aida Amini-Rankouhi; Yinlun Huang
      Abstract: Thermal energy and mechanical energy are two common forms of energy consumed significantly in the process industries. While thermal energy can be effectively recovered using matured heat integration technologies, recovery of mechanical energy through work integration has not been fully explored. It is shown that work integration can be achieved through synthesizing work exchange networks (WENs), where work exchangers are operated in a batch mode, and compressors and expanders are operated in a continuous mode; this renders network synthesis a very sophisticated design task. It is greatly beneficial if the maximum amount of mechanical energy recoverable by a WEN can be determined prior to network design. In this paper, we introduce a thermodynamic modeling and analysis method to identify accurately the maximum amount of recoverable mechanical energy of any process system of interest. The method is rigorous and general for target setting of mechanical energy recovery prior to WEN synthesis. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T07:15:28.453717-05:
      DOI: 10.1002/aic.15813
       
  • Integrated B2B-NMPC Control Strategy for Batch/Semi-batch Crystallization
           Processes
    • Authors: Qinglin Su; Richard D. Braatz, Min-Sen Chiu
      Abstract: The uncertainty in crystallization kinetics is of major concern in manufacturing processes, which can result in deterioration of most model-based control strategies. In this study, uncertainties in crystallization kinetic parameters were characterized by Bayesian probability distributions. An integrated B2B-NMPC control strategy was proposed to first update the kinetic parameters from batch to batch using a multiway partial least squares (MPLS) model, which described the variances of kinetic parameters from that of process variables and batch-end product qualities. The updated process model was then incorporated into an NMPC design, the extended prediction self-adaptive control (EPSAC), for online control of the final product qualities. Promising performance of the proposed integrated strategy was demonstrated in a simulated semi-batch pH-shift reactive crystallization process to handle major crystallization kinetic uncertainties of L-glutamic acid, wherein smoother and faster convergences than the conventional B2B control were observed when process dynamics were shifted among three scenarios of kinetic uncertainties. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T06:40:49.987292-05:
      DOI: 10.1002/aic.15810
       
  • Transitional Flow in a Rushton Turbine Stirred Tank
    • Authors: Yulong Zhang; Zhengming Gao, Zhipeng Li, J.J. Derksen
      Abstract: The way in which the single phase flow of Newtonian liquids in the vicinity of the impeller in a Rushton turbine stirred tank goes through a laminar – turbulent transition has been studied in detail experimentally (with Particle Image Velocimetry, PIV) as well as computationally. For Reynolds numbers equal to or higher than 6,000, the average velocities and velocity fluctuation levels scale well with the impeller tip speed, i.e. show Reynolds independent behavior. Surprising flow structures were measured – and confirmed through independent experimental repetitions – at Reynolds numbers around 1,300. Upon reducing the Reynolds number from values in the fully turbulent regime, the trailing vortex system behind the impeller blades weakens with the upper vortex weakening much stronger than the lower vortex. Simulations with a variety of methods (direct numerical simulations, transitional turbulence modeling) and software implementations (ANSYS-Fluent commercial software, lattice-Boltzmann in-house software) have only partial success in representing the experimentally observed laminar – turbulent transition. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T06:40:31.314913-05:
      DOI: 10.1002/aic.15809
       
  • Sonochemical Effect Induced by Hydrodynamic Cavitation: Comparison of
           Venturi/Orifice Flow Geometries
    • Authors: Sandip K. Pawar; Amit V. Mahulkar, Kuldeep Roy, Vijananand S. Moholkar, Aniruddha B. Pandit
      Abstract: This study presents comparative assessment of four cavitation devices (3 venturis and an orifice) in terms of cavitational yield. A 4-fold approach was adopted for assessment, viz. CFD simulations of cavitating flow, simulations of individual cavitation bubble dynamics, high speed photographs of cavitating flow and model reaction of potassium iodide oxidation. Influence of design parameters of cavitation devices on nature of cavitation produced in the flow was studied. Number density of cavitation bubbles in the flow and interactions among bubbles had critical influence on cavitation yield. Orifice gave the highest cavitational yield per unit energy dissipation in flow (despite lower working inlet pressure) due to low density of cavitation bubbles in flow. On contrary, occurrence of large cavitation bubble clouds in venturi flow had adverse effect on cavitational yield due to high interactions among cavitation bubbles resulting in inter-bubble coalescence and recombination of oxidizing radicals generated from cavitation bubbles. This article is protected by copyright. All rights reserved.
      PubDate: 2017-06-02T06:40:29.434247-05:
      DOI: 10.1002/aic.15812
       
  • Two-dimensional modelling of an absorbing falling film in its development
           zone
    • Authors: C. Wylock; B. Scheid
      Abstract: This work presents the modelling of a vertical falling film expanding or shrinking from the inlet manifold. Considering a stationary approach, the film shape, the flow field and the absorption rate of an ambient gas are computed. For the flow field, 1D second-order weighted integral boundary layer (WIBL) model is shown to accurately reproduce the film deformations. The gas transfer is then solved in a 2D pre-deformed domain in order to investigate the impact of the film deformations on the gas absorption rate. It is found that a significant mass transfer enhancement, as compared to a flat film, is obtained when the film is expanding due to the concomitant increase of the concentration gradient along the interface. On the contrary, a slight hindrance of the mass transfer is observed when the film is shrinking, though it remains in this case very close to the flat film analytical solution. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-30T10:40:33.173292-05:
      DOI: 10.1002/aic.15808
       
  • Hydrodynamics of Gas-Liquid Flow in Micro-Packed Beds: Pressure Drop,
           Liquid Holdup and Two-Phase Model
    • Authors: Jisong Zhang; Andrew R. Teixeira, Lars Thilo Kögl, Lu Yang, Klavs F. Jensen
      Abstract: Hydrodynamics of gas-liquid two-phase flow in micro-packed beds are studied with a new experimental setup. The pressure drop, residence time distribution and liquid holdup are measured with gas and liquid flow rates varying from 4 to 14 sccm and 0.1 to 1 ml/min, respectively. Key parameters are identified to control the experimentally observed hydrodynamics, including transient start-up procedure, gas and liquid superficial velocities, particle and packed bed diameters and physical properties of the liquids. Contrary to conventional large packed beds, our results demonstrate that in these micro-systems, capillary forces have a large effect on pressure drop and liquid holdup, while gravity can be neglected. A mathematical model describes the hydrodynamics in the micro-packed beds by considering the contribution of capillary forces, and its predictions are in good agreement with experimental data. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-26T19:40:24.715805-05:
      DOI: 10.1002/aic.15807
       
  • Experimental Proof of the Existence of Mass Transfer Resistance During
           Early Stages of Ethylene Polymerization with Silica supported
           Metallocene/MAO Catalysts
    • Authors: Muhammad Ahsan Bashir; Vincent Monteil, Christophe Boisson, Timothy F. L. McKenna
      Abstract: The size of a silica supported metallocene/MAO catalyst plays an important role in determining its productivity during ethylene polymerization. From a chemical engineering point of view, this size dependency of catalytic activity of supported metallocenes is mathematically connected with the different levels of mass transfer resistance in big and small catalyst particles but no experimental evidence has been provided to date. The results of the present systematic experimental study clearly demonstrate that the intraparticle monomer diffusion resistance is high in bigger catalyst particles during initial instants of ethylene polymerization and diminishes with the passage of polymer particle growth. Two different silica supported metallocene/MAO catalysts provided the same results while highlighting the fact that catalyst chemistry should be carefully considered while studying complex chemical engineering problems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-26T19:35:27.09659-05:0
      DOI: 10.1002/aic.15806
       
  • Molecular Transport through Mixed Matrix Membranes: A Time-Dependent
           Density Functional Approach
    • Authors: Yu Liu; Fangyuan Guo, Jun Hu, Honglai Liu, Ying Hu
      Abstract: The transport properties of gases in mixed matrix membranes (MMMs) are important in materials design. Here, we developed a novel time-dependent density functional theory (TDDFT) method to study the transport properties of gases in MMMs. The MMM is modeled by inserting a spherical filler into the continuous polymer phase, which is similar to the Maxwell model; additionally, the inhomogeneity of the filler and the molecular correlations were taken into account in the TDDFT method. Transport properties such as permeation, density profile, flux and chemical potential are examined and discussed. We found that the TDDFT prediction of the permeation is higher than that of the Maxwell model, and the filler-polymer interface is key to tuning this effect, which also seems to be the dominating factor in the transport process on both the microscopic and macroscopic scale. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-25T17:19:21.867528-05:
      DOI: 10.1002/aic.15805
       
  • Stochastic Programming Models for Optimal Shale Well Development and
           Refracturing Planning under Uncertainty
    • Authors: Markus G. Drouven; Diego C. Cafaro, Ignacio E. Grossmann
      Abstract: In this work we present an optimization framework for shale gas well development and refracturing planning. This problem is concerned with if and when a new shale gas well should be drilled at a prospective location, and whether or not it should be refractured over its lifespan. We account for exogenous gas price uncertainty and endogenous well performance uncertainty. We propose a mixed-integer linear, two-stage stochastic programming model embedded in a moving horizon strategy to dynamically solve the planning problem. A generalized production estimate function is described that predicts the gas production over time depending on how often a well has been refractured, and when exactly it was restimulated last. From a detailed case study, we conclude that early in the life of an active shale well, refracturing makes economic sense even in low-price environments, whereas additional restimulations only appear to be justified if prices are high. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-25T17:00:27.32088-05:0
      DOI: 10.1002/aic.15804
       
  • Gravity Induced Coalescence in Emulsions with High Volume Fractions of
           Dispersed Phase in the Presence of Surfactants
    • Authors: Meenakshi Mazumdar; Shantanu Roy
      Abstract: We report studies on the effect of volume fraction and surfactant concentration on the kinetics of destabilization of emulsions under the influence of gravity. Model oil-in-water emulsions, designed to mimic crude oil-water emulsions, were prepared with varying volume fractions of dispersed oil but nearly identical normalized initial drop size distributions. The gravity separation process was observed by periodically withdrawing samples and arresting further coalescence, and examining the droplet size distribution under the microscope. Experiments were carried out for three volume fractions of dispersed phase and two surfactant concentrations (0.4% and 1.6% by weight). At higher oil fractions (20%) and a lower surfactant concentration (0.4%), it was observed that although the rate of coalescence increased, the actual oil separation of was delayed and reduced rates of creaming were observed. At higher surfactant concentrations (1.6%), the dominant factor in suppressing destabilization is the rate of drop to interface coalescence. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-25T17:00:24.699423-05:
      DOI: 10.1002/aic.15803
       
  • Indirect Conduction in Gas-Solids Systems: Static vs. Dynamic Effects
    • Authors: Aaron M. Lattanzi; Christine M. Hrenya
      Abstract: Conductive mechanisms play an integral role in the transfer of heat through dense gas-solid systems. In particular, the conduction occurring through a thin layer of fluid between the solids (indirect) can become the primary mode for heat transfer within gas-solid systems. However, attempts to evaluate the effect of surface roughness and fluid lens thickness (theoretical inputs) on indirect conduction have been restricted to static, single-particle cases. By contrast, here we quantify these effects for dynamic, multi-particle systems using a non-dimensional, average heat transfer coefficient that is obtained via techniques commonly employed by classic kinetic theory. Analytical predictions for the impact of theoretical inputs on indirect conduction are compared to outputs from computational fluid dynamics – discrete element method simulations. The analytical predictions are in agreement with simulations and show that indirect conduction in static systems is most sensitive to surface roughness, while dynamic systems are sensitive to the fluid lens thickness. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-23T04:55:30.680415-05:
      DOI: 10.1002/aic.15802
       
  • Particle-Laden Liquid Jet Impingement On A Moving Substrate
    • Authors: Hatef Rahmani; Sheldon I. Green
      Abstract: The impingement of high speed jets on a moving surface was studied. The jet fluids were dilute suspensions of neutrally buoyant particles in water-glycerin solutions. At these low particle concentrations, the suspensions have Newtonian fluid viscosity. A variety of jet and surface velocities, solution properties, nozzle diameters, mean particle sizes, and volume fractions were studied. For each case the splash-deposition threshold was quantified. It was observed that for jets with very small particles, addition of solids to the jet enhances deposition and postpones splash relative to a particle-free water-glycerin solution with the same viscosity. In contrast, jets with larger particles in suspension were more prone to splash than single phase jets of the same viscosity. It is speculated that the change in character of the splash response for the jets with larger particles in suspension occurs when the particle diameter is comparable to the lamella thickness. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-23T04:55:29.523336-05:
      DOI: 10.1002/aic.15800
       
  • Mixing dynamics in bubbling fluidized beds
    • Authors: A. Bakshi; C. Altantzis, A.F. Ghoniem
      Abstract: Solids mixing affects thermal and concentration gradients in fluidized bed reactors and is, therefore, critical to their performance. Despite substantial effort over the past decades, understanding of solids mixing continues to be lacking because of technical limitations of diagnostics in large pilot and commercial-scale reactors. This study is focused on investigating mixing dynamics and their dependence on operating conditions using CFD simulations. Towards this end, fine-grid 3D simulations are conducted for the bubbling fluidization of three distinct Geldart B particles (1.15 mm LLDPE, 0.50 mm glass and 0.29 mm alumina) at superficial gas velocities U/Umf =2-4 in a pilot-scale 50 cm diameter bed. The Two-Fluid Model (TFM) is employed to describe the solids motion efficiently while bubbles are detected and tracked using MS3DATA. Detailed statistics of the flow-field in and around bubbles are computed and used to describe bubble-induced solids micromixing: solids upflow driven in the nose and wake regions while downflow along the bubble walls. Further, within these regions, the hydrodynamics are dependent only on particle and bubble characteristics, and relatively independent of the global operating conditions. Based on this finding, a predictive mechanistic, analytical model is developed which integrates bubble-induced micromixing contributions over their size and spatial distributions to describe the gross solids circulation within the fluidized bed. Finally, it is shown that solids mixing is affected adversely in the presence of gas bypass, or throughflow, particularly in the fluidization of heavier particles. This is because of inefficient gas solids contacting as 30-50% of the superficial gas flow escapes with 2-3× shorter residence time through the bed. This is one of the first large-scale studies where both the gas (bubble) and solids motion, and their interaction, are investigated in detail and the developed framework is useful for predicting solids mixing in large-scale reactors as well as for analyzing mixing dynamics in complex reactive particulate systems. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-23T04:55:22.432144-05:
      DOI: 10.1002/aic.15801
       
  • A Green Process for Recovery of H2SO4 and Fe2O3 from FeSO4·7H2O by
           Modeling Phase Equilibrium of the Fe(П)‒SO42‒‒H+‒Cl‒ System
    • Authors: Yan Zhang; Zhibao Li, Yan Zeng, George P. Demopoulos
      Abstract: Ferrous sulfate heptahydrate FeSO4·7H2O is a major waste produced in titanium dioxide industry by the sulfate process and has caused heavy environmental problem. A new green process for the treatment of FeSO4·7H2O was proposed to make use of iron source and recycle sulfate source as H2SO4. It was found that by adding concentrated HCl to the FeSO4 solution, FeCl2·4H2O was crystallized out, which was subsequently calcined to produce Fe2O3 and HCl. Concentrated H2SO4 solution (about 65 wt%) was obtained by evaporating the FeCl2·4H2O-saturated filtrate. To facilitate the process development and design, the solubilities of FeCl2·4H2O in HCl, H2SO4, and HCl+H2SO4 solutions were measured and the experimental data were regressed with both the mixed-solvent electrolyte (MSE) model and the electrolyte NRTL model. On the basis of the prediction of the optimum conditions for the crystallization of FeCl2·4H2O, material balance of the new process was calculated. FeCl2·4H2O and Fe2O3 were obtained from a laboratory-scale test with about 70% recovery of ferrous source for a single cycle, indicating the feasibility of the process. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-19T06:15:32.86278-05:0
      DOI: 10.1002/aic.15795
       
  • Modeling of CO2 Equilibrium Solubility in a Novel
           1-diethylamino-2-Propanol Solvent
    • Authors: Helei Liu; Min Xiao, Xiao Luo, Hongxia Gao, Raphael Idem, Paitoon Tontiwachwuthikul, Zhiwu Liang
      Abstract: In this work, the equilibrium solubility of CO2 in a 1-diethylamino-2-propanol (1DEA2P) solution was determined as a function of 1DEA2P concentration (over the range of 1-2M), temperature (in the range of 298-333K), and CO2 partial pressure (in the range of 8-101kPa). These experimental results were used to fit the present correlation for K2 (Kent-Eisenberg model, Austgen model, and Li-Shen model). It was found that all of the models could represent the CO2 equilibrium solubility in 1DEA2P solution with ADDs for Kent-Eisenberg model, Austgen model, and Li-Shen model of 6.3%, 7.3% and 12.2%, respectively. A new K2 correlation model, the Liu-Helei model, was also developed to predict the CO2 equilibrium solubility in 1DEA2P solution with an excellent ADD of 3.4%. In addition, the heat of absorption of CO2 in 1DEA2P solution estimated by using the Gibbs-Helmholtz equation was found to be -45.7±3.7 kJ/mol. Information and guidelines about effectively using data for screened solvents is also provided based on the three absorption parameters: CO2 equilibrium solubility, second order reaction constant (k2), and CO2 absorption heat. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-19T05:50:38.187229-05:
      DOI: 10.1002/aic.15797
       
  • Effects of Protein Properties on Adsorption and Transport in
           Polymer-grafted Ion Exchangers: A Multiscale Modeling Study
    • Authors: Joseph E. Basconi; Giorgio Carta, Michael R. Shirts
      Abstract: We use multiscale modeling to study how the molecular properties of a protein affect its adsorption and transport in ion exchange (IEX) chromatography matrices with either open pores or charged polymers grafted into the pore structure. Coarse-grained molecular dynamics (MD) simulations of lysozyme, bovine serum albumin (BSA), and immunoglobulin (IgG) show that higher protein net charge leads to greater partitioning into the polymer-grafted pore space but slower diffusion there due to favorable electrostatic interactions, while larger size decreases both pore space partitioning and diffusion due to steric effects of the polymers. Mass transfer simulations based on the MD results show that the polymer-grafted systems can enhance the adsorption kinetics if pore space partitioning and diffusion are both sufficiently high. The simulations illustrate that to achieve fast adsorption kinetics, there is a tradeoff between favorable binding and rapid diffusion which largely depends on the charge and size of the protein. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-19T05:35:25.086719-05:
      DOI: 10.1002/aic.15798
       
  • Magnetohydrodynamics thin film fluid flow under the effect of
           thermophoresis and variable fluid properties
    • Authors: L Ali; I Saeed, T Gul, A Alshomrani, I Khan, K Aurangzeb
      Abstract: The thin film flow of fluid over a stretching sheet with variable fluid properties under the effect of thermophoresis has been investigated. A transverse magnetic field is also applied to the fluid flow in the presence of thermal radiation. The governing equations have been transformed through suitable similarity variables into nonlinear coupled differential equations with physical conditions. The solution of the coupled problem has been obtained by using the second alternative of OHAM (OHAM-2). The solution of the coupled problem through this new method and its fast convergence is mainly focused in this work. The effect of physical parameters appears in the problem are shown graphically and discussed. Finally, the obtained results are compared with a numerical (ND-Solve) method to authenticate the code of the OHAM-2. The physical and numerical agreement of these two methods has been shown. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-18T07:05:26.299711-05:
      DOI: 10.1002/aic.15794
       
  • Accurate thermodynamic modeling of ionic liquids/metal salt mixtures:
           Application to carbon monoxide reactive absorption
    • Authors: Gabriel Zarca; Inmaculada Ortiz, Ane Urtiaga, Fèlix Llovell
      Abstract: For the first time, a theoretical semi-predictive approach based on the soft-SAFT equation of state is presented to model the complexation reaction between carbon monoxide (CO) in a combined ionic liquid (IL) plus a copper(I) metallic salt media in terms of the gas solubility as a function of temperature, pressure and composition. Two different degrees of molecular approximation are tested. In the first approach, the IL-metal salt mixture is treated as a single compound whose parameters are modified according to the concentration of the metallic salt. In the second approach, both compounds are treated as independent species, enhancing the predictive capability of the model. The complexation between CO molecules and the metal salt is reproduced by adding specific cross-association interaction sites that simulate the reaction. The density of the doped IL and the CO solubility are described in quantitative agreement with the experimental data at different operating conditions. This article is protected by copyright. All rights reserved.
      PubDate: 2017-05-12T10:46:30.025594-05:
      DOI: 10.1002/aic.15790
       
  • One-Pot Synthesis of Silver-Modified Sulfur-Tolerant Anode for SOFCs with
           an Expanded Operation Temperature Window
    • Authors: Jifa Qu; Wei Wang, Tao Yang, Yubo Chen, Zongping Shao
      Abstract: To develop solid oxide fuel cells (SOFCs) capable of operating on sulfur-containing practical fuels at intermediate temperatures, further improvement of the sulfur tolerance of a Ni+BaZr0.4Ce0.4Y0.2O3-δ (BZCY) anode is attempted through the addition of some metal modifiers (Fe, Co and Ag) by a one-pot synthesis approach. The effects of these modifiers on the electrical conductivity, morphology, sulfur tolerance and electrochemical activity of the anode are systematically studied. As a result, the cell with Ag-modified Ni+BZCY anode demonstrates highest power output when operated on 1000 ppm H2S-H2 fuel. Furthermore, the Ag-modified anode displays much better stability than Ni+BZCY with 1000 ppm H2S-H2 fuel at 600°C. These results suggest that the addition of Ag modifier into Ni+BZCY is a promising and efficient method for improving the sulfur tolerance of SOFCs. This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-17T04:36:22.37746-05:0
      DOI: 10.1002/aic.15649
       
  • Issue information - table of contents
    • Pages: 3245 - 3245
      PubDate: 2017-07-03T12:29:08.293832-05:
      DOI: 10.1002/aic.15476
       
  • Absorption methods for the determination of mass transfer parameters of
           packing internals: A literature review
    • Authors: Laszlo Hegely; John Roesler, Pascal Alix, David Rouzineau, Michel Meyer
      Pages: 3246 - 3275
      Abstract: Methods for the determination of mass-transfer coefficients and effective interfacial areas in packed absorption columns are reviewed. For each parameter, the methods are grouped into categories on the basis of their physical principle; the chemical systems used, experimental protocol, and the advantages and inconveniences are discussed. The treatment of end effects, the influence of packed bed height, and the recent efforts in standardization of measurement methods are also treated. The aim of the review is to give a broad overview of the methods used in literature in the last eight decades, some of which might be reconsidered in the light of modern measurement techniques and to evaluate them in relation to precision, practicality and hazardousness thereby to facilitate the search for reliable, precise, and convenient experimental practices. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3246–3275, 2017
      PubDate: 2017-04-25T11:35:32.700871-05:
      DOI: 10.1002/aic.15737
       
  • Liquid-like wave structure on granular film from granular jet impact
    • Authors: Zhe-Hang Shi; Wei-Feng Li, Hai-Feng Liu, Fu-Chen Wang
      Pages: 3276 - 3285
      Abstract: Results in the literature show that a granular film appears from a dense granular jet impacting on a circular target under certain conditions (Cheng X, Varas G, Citron D, Jaeger HM, Nagel SR, Phys Rev Lett. 2007; 99(18):188001). In current study, granular jet impacts are experimentally studied using a high-speed camera, and interesting liquid-like wave structures on the granular film are observed with increasing granular jet velocities or decreasing solid fractions of granular jets. Effects of the particle diameter, the granular jet velocity, and the solid fraction of granular jet on the wave structures are investigated. The dynamic characteristics of granular wave such as the wave frequency and velocity are demonstrated and compared with the liquid jet impact. Results reveal that increasing pushing pressure enhances the gas-particle interaction inside the nozzle, which causes the granular jet instability and further gives rise to the granular wave at lower solid fractions and higher granular jet velocities. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3276–3285, 2017
      PubDate: 2017-03-07T08:20:39.040666-05:
      DOI: 10.1002/aic.15693
       
  • On the modeling of the co2-catalyzed sintering of calcium oxide
    • Authors: Juan C. Maya; Farid Chejne, Suresh K. Bhatia
      Pages: 3286 - 3296
      Abstract: A comprehensive mathematical model for the CO2-catalyzed sintering of CaO is proposed. It takes into account the mechanisms of surface diffusion and grain boundary diffusion, catalyzed by CO2 chemisorption and dissolution, respectively. In addition, the model proposed here considers the change in pore size distribution during sintering, grain growth, and the densification by lattice diffusion, which is the intrinsic sintering mechanism of the CaO. Model predictions are validated using experimental data on the sintering of two CaO samples, one of them derived from pure CaCO3 and the other from limestone. It is found that impurities in limestone-derived CaO do not significantly affect the CO2 dissolution or chemisorption processes; however, they strongly increase the rate of sintering by lattice diffusion. It is also established that low temperatures and CO2 partial pressures promote the coarsening by surface diffusion, whereas high temperatures and CO2 partial pressures favor densification. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3286–3296, 2017
      PubDate: 2017-03-11T09:55:32.27356-05:0
      DOI: 10.1002/aic.15696
       
  • Formation process of core-shell microparticles by solute migration during
           drying of homogenous composite droplets
    • Authors: Nan Fu; Winston Duo Wu, Zhangxiong Wu, Fei Tzhung Moo, Meng Wai Woo, Cordelia Selomulya, Xiao Dong Chen
      Pages: 3297 - 3310
      Abstract: Particle formation process during spray drying profoundly impacts particle morphology and microstructure. This study experimentally investigated the formation of core-shell-structured microparticles by one-step drying of composite droplets made of Eudragit® RS (a polycationic acrylic polymer in nanoparticle form) and silica sol. The formation of an incipient surface shell was monitored using single droplet drying technique, and the freshly formed shell was recovered for subsequent analyses. Adding silica to RS precursor increased the shell formation time and altered the properties of the incipient shell from water-dispersible to nondispersible. The incipient shell formed from RS/silica droplets with mass ratios of 1.5%:1.5% and 0.5%:2.5% showed ingredient segregation with a preferential accumulation of RS, similar to the shell region of dried microparticles. After shell formation, excess silica sol in the liquid phase could flow inward, producing a dense core. This mobility-governed solute migration would be useful for constructing core-shell microparticles using other precursor systems. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3297–3310, 2017
      PubDate: 2017-03-29T09:45:54.158467-05:
      DOI: 10.1002/aic.15713
       
  • Data mining and control loop performance assessment: The multivariate case
    • Authors: Laya Das; Raghunathan Rengaswamy, Babji Srinivasan
      Pages: 3311 - 3328
      Abstract: Control loop performance assessment (CLPA) techniques assume that the data being analyzed is generated during steady state operation with fixed plant dynamics and controller parameters. However, in industrial settings one often encounters environmental and feedstock variations which can induce significant changes in the plant dynamics. Availability of data sets corresponding to fixed configurations is therefore questionable in industrial scenarios, in which case it becomes imperative to extract the same from routine plant operating data. This article proposes a technique for segmenting multivariate control loop data into portions corresponding to fixed steady state operation of the system. The proposed technique exploits the fact that changes in the operating region of the system lead to changes in variance-covariance matrix of multivariate control loop data. The univariate interval halving technique is fused with Mahalanobis distance to develop a multivariate tool that accounts for interactions between variables. The resulting data segments can be used for reliable CLPA and/or for user defined benchmarking of control loops. A multivariate control loop performance index is also proposed that requires significantly less data as compared to one of the previously proposed techniques. The proposed technique requires only routine operating data from the plant, and is tested on benchmark systems in the literature with simulations. Experimental validation on a model predictive control system aimed at maintaining the temperature profile of a metal plate demonstrates applicability of the technique to industrial systems. The proposed technique acts as a tool for preprocessing data relevant to CLPA and can be applied to large scale interacting multivariate systems. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3311–3328, 2017
      PubDate: 2017-03-09T11:20:45.943263-05:
      DOI: 10.1002/aic.15689
       
  • Performance and kinetics of membrane and hybrid moving bed
           biofilm-membrane bioreactors treating salinity wastewater
    • Authors: Alejandro Rodríguez-Sánchez; Juan Carlos Leyva-Díaz, José Manuel Poyatos, Jesús González-López
      Pages: 3329 - 3342
      Abstract: A pilot-plant membrane bioreactor (MBR) and two pilot-plant hybrid moving bed biofilm reactor–membrane bioreactors (MBBR–MBRs), divided into three aerobic and one anoxic chambers, were started up for the treatment of salinity-amended urban wastewater. The MBBR–MBR systems worked with and without carriers in the anoxic zone (MBBR–MBRanox and MBBR–MBRn/anox, respectively). The systems were operated from start-up to stabilization, showing high removal of organic matter—a maximum of 90% chemical oxygen demand and 98% biochemical oxygen demand on the fifth day for MBBR–MBRn/anox in the stabilization phase—but low nitrogen elimination—30% maximum for MBBR–MBRn/anox in the stabilization phase. Biofilm attached to carriers reached less than 50 mg L−1 in the hybrid system. MBR showed faster kinetics than the two MBBR–MBR systems during start-up, but the opposite occurred during stabilization. Maximum specific growth rates for heterotrophic and autotrophic biomass were 0.0500 and 0.0059 h−1 for MBBR–MBRn/anox in the stabilization phase. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3329–3342, 2017
      PubDate: 2017-03-09T11:25:27.071477-05:
      DOI: 10.1002/aic.15694
       
  • Modularization strategy for syngas generation in chemical looping methane
           reforming systems with CO2 as feedstock
    • Authors: Mandar Kathe; Charles Fryer, Peter Sandvik, Fanhe Kong, Yitao Zhang, Abbey Empfield, Liang-Shih Fan
      Pages: 3343 - 3360
      Abstract: This study considers a CO2 feedstock in conventional methane reforming processes and metal oxide lattice oxygen based chemical looping reforming. Lattice oxygen from iron-titanium composite metal oxide provides the most efficient co-utilization of CO2 with CH4. A modularization chemical looping strategy is developed to further improve process efficiencies using a thermodynamic rationale. Modularization leverages the ability of two or more reactors operating in parallel to produce a higher quality syngas than a single reactor operating alone while offering a direct solution to scale up of multiple parallel reactor processes. Experiments conducted validate the thermodynamic simulation results. Simulation and experimental results ascertain that a cocurrent moving bed in a modularization system can operate under CO2 neutral or negative conditions. The results for a modularization process system for 7950 m3 per day (50,000 barrels per day) of liquid fuel indicate a ∼23% reduction of natural gas usage over baseline-case. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3343–3360, 2017
      PubDate: 2017-03-18T15:20:52.671359-05:
      DOI: 10.1002/aic.15692
       
  • A comparison of efficient uncertainty quantification techniques for
           stochastic multiscale systems
    • Authors: Grigoriy Kimaev; Luis A. Ricardez-Sandoval
      Pages: 3361 - 3373
      Abstract: The aim of this article is to compare the performance of efficient uncertainty propagation techniques (Polynomial Chaos [PCE] and Power Series [PSE] expansions) for uncertainty quantification in multiscale systems where discrete (molecular) scale is modeled without closed-form expressions. A multiscale model of thin film formation by chemical vapor deposition was used to study the effects of single parameter and multivariate uncertainty. For the single parameter uncertainty, 2nd order PSE approximations were the most accurate and computationally attractive. For the multivariate uncertainty, PSE performance deteriorated, while 2nd order PCE provided the highest accuracy when its expansion coefficients were calculated using the Least Squares method. However, comparable accuracy was achieved at half the computational cost when the coefficients were calculated using Nonintrusive Spectral Projection (NISP). The response variables were subsequently controlled using robust optimization, and the results obtained using PCE NISP satisfied the optimization constraints more closely than other methods. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3361–3373, 2017
      PubDate: 2017-03-18T15:45:36.985387-05:
      DOI: 10.1002/aic.15702
       
  • A new qualitative trend analysis algorithm based on global polynomial fit
    • Authors: Bo Zhou; Hao Ye, Haifeng Zhang, Mingliang Li
      Pages: 3374 - 3383
      Abstract: Qualitative trend analysis (QTA) is an effective tool for process data analysis, the applications of which can be found in a variety of fields, such as process monitoring, fault diagnosis, and data mining. Reliable and accurate trend extraction of sensor data is the first and indispensable step in QTA. In this article, a new trend extraction algorithm is developed that is based on global optimization of the polynomial fit of the process data. Different from most existing works, this newly proposed algorithm solves the trend extraction task by simultaneously and globally estimating the episode number, the boundary time points of the episode, and the fitted polynomial coefficients, which shows improved performance over other nonglobally optimal trend extraction algorithms and requires less a priori knowledge than the existing globally optimal trend algorithms. The effectiveness of the algorithm is illustrated by testing on a variety of simulation and real blast furnace data. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3374–3383, 2017
      PubDate: 2017-03-23T10:15:32.552803-05:
      DOI: 10.1002/aic.15706
       
  • Multi-rate observer design for process monitoring using asynchronous
           inter-sample output predictions
    • Authors: Chen Ling; Costas Kravaris
      Pages: 3384 - 3394
      Abstract: In this article, the problem of observer design in linear multi-output systems with asynchronous sampling is addressed. The proposed multi-rate observer is based on a continuous-time Luenberger observer design coupled with an inter-sample predictor for each sampled measurement, which generates an estimate of the output in between consecutive measurements. The sampling times are not necessarily uniformly spaced, but there exists a maximum sampling period among all the sensors. Sufficient and explicit conditions are derived to guarantee exponential stability of the multi-rate observer. The proposed framework of multi-rate observer design is examined through a mathematical example and a gas-phase polyethylene reactor. In the latter case, the amount of active catalyst sites is estimated, with a convergence rate that is comparable to the case of continuous measurements. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3384–3394, 2017
      PubDate: 2017-03-23T10:15:43.918143-05:
      DOI: 10.1002/aic.15707
       
  • A new model for correlation and prediction of equilibrium CO2 solubility
           in N-methyl-4-piperidinol solvent
    • Authors: Min Xiao; Ding Cui, Helei Liu, Paitoon Tontiwachwuthikul, Zhiwu Liang
      Pages: 3395 - 3403
      Abstract: In this work, the equilibrium CO2 solubility in the aqueous tertiary amine, N-methyl-4-piperidinol (MPDL) was measured over a range of temperatures, CO2 partial pressures and amine concentrations. The dissociation constant of the MPDL solution was determined as well. A new thermodynamic model was developed to predict the equilibrium CO2 solubility in the MPDL-H2O-CO2 system. This model, equipped with the correction factor (Cf), can give reasonable prediction with an average absolute deviation of 2.0%, and performs better than other models (i.e., KE model, Li-Shen model, and Hu-Chakma). The second-order reaction rate constant (k2) of MPDL and the heat of CO2 absorption (–ΔHabs) into aqueous MPDL solutions were evaluated as well. Based on the comparison with some conventional amines, MPDL revealed a high-equilibrium CO2 loading, reasonably fast absorption rate when compared with other tertiary amines, and a low energy requirement for regeneration. It may, therefore, be considered to be an alternative solvent for CO2 capture. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3395–3403, 2017
      PubDate: 2017-03-23T10:20:31.438051-05:
      DOI: 10.1002/aic.15709
       
  • Distributed economic model predictive control for operational safety of
           nonlinear processes
    • Authors: Fahad Albalawi; Helen Durand, Panagiotis D. Christofides
      Pages: 3404 - 3418
      Abstract: Achieving operational safety of chemical processes while operating them in an economically-optimal manner is a matter of great importance. Our recent work integrated process safety with process control by incorporating safety-based constraints within model predictive control (MPC) design; however, the safety-based MPC was developed with a centralized architecture, with the result that computation time limitations within a sampling period may reduce the effectiveness of such a controller design for promoting process safety. To address this potential practical limitation of the safety-based control design, in this work, we propose the integration of a distributed model predictive control architecture with Lyapunov-based economic model predictive control (LEMPC) formulated with safety-based constraints. We consider both iterative and sequential distributed control architectures, and the partitioning of inputs between the various optimization problems in the distributed structure based on their impact on process operational safety. Moreover, sufficient conditions that ensure feasibility and closed-loop stability of the iterative and sequential safety distributed LEMPC designs are given. A comparison between the proposed safety distributed EMPC controllers and the safety centralized EMPC is demonstrated via a chemical process example. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3404–3418, 2017
      PubDate: 2017-03-24T10:06:17.561367-05:
      DOI: 10.1002/aic.15710
       
  • Optimal water management in macroscopic systems under economic penalty
           scenarios
    • Authors: Jaime Garibay-Rodriguez; Vicente Rico-Ramirez, Jose M. Ponce-Ortega
      Pages: 3419 - 3441
      Abstract: An integrated optimization approach to assess the sustainability of water management strategies in a macroscopic system is proposed. Those strategies include alternative water sources, such as rainwater harvesting, and the design of distributed water treatment systems. To deal with the economic challenges inherent to wastewater treatment, an economic penalization scheme is presented as an alternative that can achieve better cost-effectiveness and pollution abatement than traditional command and control practices. The proposed approach results in an MINLP multiperiod model, which has been solved through the GAMS® modeling environment. The solution of our case-study allows finding the minimum investment to meet the desired environmental goals with respect to freshwater consumption and pollution abatement. Results include the number, size, and location of rainwater storage devices as well as treatment technologies, the total amount of recycled wastewater, and the total amount of fines charged to the users for violation of environmental regulations. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3419–3441, 2017
      PubDate: 2017-03-24T10:05:52.396677-05:
      DOI: 10.1002/aic.15712
       
  • Ceria-coated diesel particulate filters for continuous regeneration
    • Authors: Valeria Di Sarli; Gianluca Landi, Luciana Lisi, Almerinda Di Benedetto
      Pages: 3442 - 3449
      Abstract: The potential of diesel particulate filters wash-coated with highly dispersed nano-metric ceria particles for continuous regeneration has been investigated. To this end, catalytic filters were prepared, soot-loaded (avoiding the formation of the cake layer), and regenerated—under isothermal conditions—at temperature ranging from 200–600°C. Results have shown that catalytic oxidation of soot starts from 300°C and, at all temperatures, the selectivity to CO2 is higher than 99%. 475°C is the minimum temperature at which the filter is regenerated via catalytic path. At this temperature, the catalytic filter maintains substantially the same performance over repeated cycles of soot loading and regeneration, indicating that the thermal stability of ceria is preserved. This has been further confirmed by comparison between the outcomes obtained from characterization (X-ray powder diffraction, N2 adsorption at 77 K, Hg intrusion porosimetry, and scanning electron microscope/energy dispersive X-ray analysis) of fresh filter and filter subjected to repeated regeneration tests. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3442–3449, 2017
      PubDate: 2017-03-07T08:40:45.270806-05:
      DOI: 10.1002/aic.15688
       
  • A novel CeO2–xSnO2/Ce2Sn2O7 pyrochlore cycle for enhanced solar
           thermochemical water splitting
    • Authors: Chongyan Ruan; Yuan Tan, Lin Li, Junhu Wang, Xiaoyan Liu, Xiaodong Wang
      Pages: 3450 - 3462
      Abstract: A novel CeO2–xSnO2/Ce2Sn2O7 pyrochlore stoichiometric redox cycle with superior H2 production capacities is identified and corroborated for two-step solar thermochemical water splitting (STWS). During the first thermal reduction step (1400°C), a reaction between CeO2 and SnO2 occurred for all the CeO2–xSnO2 (x = 0.05–0.20) solid compounds, forming thermodynamically stable Ce2Sn2O7 pyrochlore rather than metastable CeO2-δ. Consequently, substantially higher reduction extents were achieved owing to the reduction of CeIV to CeIII. Moreover, in the subsequent reoxidation with H2O (800°C), H2 production capacities increased by a factor of 3.8 as compared to the current benchmark material ceria when x = 0.15, with the regeneration of CeO2 and SnO2 and the concomitant reoxidation of CeIII to CeIV. The H2O-splitting performance for CeO2–0.15SnO2 was reproducible over seven consecutive redox cycles, indicating the material was also robust. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3450–3462, 2017
      PubDate: 2017-03-17T11:05:54.088717-05:
      DOI: 10.1002/aic.15701
       
  • Metal-free boron nitride adsorbent for ultra-deep desulfurization
    • Authors: Jun Xiong; Huaming Li, Lei Yang, Jing Luo, Yanhong Chao, Jingyu Pang, Wenshuai Zhu
      Pages: 3463 - 3469
      Abstract: Activated metal-free boron nitride (BN) adsorbent has been prepared by a surfactant assisted regulation strategy. By tuning the variety of surfactants (such as P123, PVP, F127), usage and reaction temperature, the adsorptive performance of activated BN was optimized. The optimized BN-P123 adsorbent displays porous structure with a high surface area about 1185 m2/g and exhibits excellent adsorptive desulfurization activity for dibenzothiophene (45.7 mg S/g adsorbent for 500 ppmw sulfur model oil), which is comparable or even superior to the state-of-the-art adsorbent. Additionally, this activated BN-P123 could realize the ultra-deep desulfurization through adsorptive process to reach the latest international standard (less than 10 ppmw). Considering the nontoxic metal-free feature and the excellent adsorption performance, the obtained activated BN-P123 may be a powerful candidate to meet the requirements of potential industrial applications. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3463–3469, 2017
      PubDate: 2017-03-11T10:05:28.863551-05:
      DOI: 10.1002/aic.15695
       
  • Efficient removal of organic dye pollutants using covalent organic
           frameworks
    • Authors: Xiang Zhu; Shuhao An, Yu Liu, Jun Hu, Honglai Liu, Chengcheng Tian, Sheng Dai, Xuejing Yang, Hualin Wang, Carter W. Abney, Sheng Dai
      Pages: 3470 - 3478
      Abstract: A rational design and synthesis of covalent organic frameworks (COFs) displaying efficient adsorption of surrogates for common organic pollutants is demonstrated herein. Significantly, the top performing mesoporous triazine-functionalized polyimide COF exhibits superior adsorption of the small dye molecule methylene blue, achieving a maximum adsorption capacity of ∼1691 mg g−1 (∼169 wt %), surpassing the performance of all previously reported nanoporous adsorbents. The experimental results and accompanying in silico simulations suggest that both the size of the organic dye molecules and the intrinsic pore-size effect of the COF material should be taken into account simultaneously for the construction of COF-based adsorbents with efficient dyes adsorption capacities. The structural diversity of COF materials along with the understanding of the encapsulation of organic dyes on COFs holds great promise for developing novel COF adsorbents for the efficient removal of organic pollutants from wastewater. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3470–3478, 2017
      PubDate: 2017-03-13T22:30:42.479794-05:
      DOI: 10.1002/aic.15699
       
  • Mass transfer enhancement in non-dispersive solvent extraction with
           helical hollow fiber enabling Dean vortices
    • Authors: Qingran Kong; Youwei Cheng, Lijun Wang, Xi Li
      Pages: 3479 - 3490
      Abstract: In this work mass transfer enhancement of non-dispersive solvent extraction by use of helical hollow fiber membranes (HHFM) was investigated by means of experiment and model simulation. Purified terephthalic acid wastewater treatment by extraction with p-xylene as solvent was chosen as the application case. Experiments showed that extraction efficiency of the HHFM was doubly enhanced compared with that of the straight hollow fiber. A comprehensive mathematical model of the HHFM extraction was developed in an orthogonal helical coordinate system with an analytical solution of the 3D velocities. Model simulation revealed that Dean vortices circulate the peripheral fluid to the center, which enhances the mass transfer in the lumen side where radial diffusion is the rate determining step of the extraction. Relations of effluent impurity concentration and enhancement factor with the Graetz number and dimensionless curvature, were obtained by model simulation. Optimal parameters were selected for HHFM extraction design. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3479–3490, 2017
      PubDate: 2017-03-18T16:05:31.323462-05:
      DOI: 10.1002/aic.15700
       
  • Modeling study of oxygen permeation through an electronically
           short-circuited YSZ-based asymmetric hollow fiber membrane
    • Authors: Yun Jin; Xiuxia Meng, Naitao Yang, Bo Meng, Jaka Sunarso, Shaomin Liu
      Pages: 3491 - 3500
      Abstract: Here, oxygen fluxes through an electronically short-circuited asymmetric Ag-YSZ YSZ LSM-YSZ hollow fiber prepared via a combined spinning and sintering route were tested and correlated to an explicit oxygen permeation model. The average oxygen permeation through such asymmetric hollow fiber with a 27 μm-thick YSZ dense layer reached 0.52 mL (STP) cm−2 min−1 at 1173 K. From the model results, we can obtain the characteristic thickness, the effects of the temperature, and the effect of He sweep gas flow rate to the individual step contribution. The oxygen partial pressure variation in the permeate side, the local oxygen flux, and the three-different resistance distribution along the axial direction of the asymmetric hollow fiber are theoretically studied; providing guidelines to further improve the membrane performance for oxygen separation. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3491–3500, 2017
      PubDate: 2017-03-18T16:18:53.852471-05:
      DOI: 10.1002/aic.15703
       
  • Highly efficient recovery of propane by mixed-matrix membrane via
           embedding functionalized graphene oxide nanosheets into
           polydimethylsiloxane
    • Authors: Guoshun Shen; Jing Zhao, Kecheng Guan, Jie Shen, Wanqin Jin
      Pages: 3501 - 3510
      Abstract: To construct rapid C3H8 transport pathways in polymer matrix, alkyl chain-functionalized graphene oxide (GO) was prepared via grafting octadecylamine (ODA) molecules and then embedded into polydimethylsiloxane (PDMS) matrix to obtain high-efficiency mixed matrix membranes (MMMs). The incorporation of alkyl chains contributes to lowering the surface energy of GO nanosheets and providing higher affinity with PDMS matrix. Additionally, the alkyl chains on the surface of ODA-functionalized GO nanosheets (ODA-GO) are in favor of C3H8 adsorption, thus conferring continuous and specific transport pathways for C3H8. The optimized membrane with ODA-GO loading of 0.3 wt% exhibits the C3H8 permeance of 1897 GPU and the C3H8/N2 ideal selectivity of 67, which are 50.2 and 72.5% higher than those of bare PDMS membrane, respectively. The simultaneous enhancement of C3H8 permeance and C3H8/N2 ideal selectivity indicates that ODA-GO is an effective filler applied in MMMs for C3H8 recovery. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3501–3510, 2017
      PubDate: 2017-03-29T09:45:31.406627-05:
      DOI: 10.1002/aic.15720
       
  • Effect of membrane morphology on rising properties of filtration
           resistance in microfiltration of dilute colloids
    • Authors: Eiji Iritani; Nobuyuki Katagiri, Yuuki Yamashita
      Pages: 3511 - 3522
      Abstract: The effect of membrane morphology on the flux decline behaviors in dead-end unstirred microfiltration of very dilute colloids of polystyrene latex was examined using mixed cellulose ester and cellulose acetate membranes with interconnected tortuous pores and track-etched polycarbonate membranes with uniform straight cylindrical pores. The plots of reciprocal filtration rate against the filtrate volume per unit membrane area for the former two membranes exhibit concave downward curves in the initial period when the membrane pore blocking is significant, whereas the plot for the latter shows a concave upward curve in that period. The former results were described by a serial resistance model consisting of the initial membrane pore blocking followed by filter cake growth, and the latter was represented by a parallel resistance model in which the pore blocking and cake growth develop simultaneously from the beginning of filtration. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3511–3522, 2017
      PubDate: 2017-03-30T09:11:15.339096-05:
      DOI: 10.1002/aic.15719
       
  • Molecular understanding of pyridinium ionic liquids as absorbents with
           water as refrigerant for use in heat pumps
    • Authors: Pablo B. Sánchez; Mounir Traikia, Alain Dequid, Agílio A. H. Pádua, Josefa García
      Pages: 3523 - 3531
      Abstract: Aiming at developing new absorbent/refrigerant working pairs for heat pumps, thermodynamic and transport properties of two pyridinium ionic liquids (ILs), N-ethylpyridinium bis(trifluoromethanesulfonyl)amide and N-ethylpyridinium trifluoromethanesulfonate were studied using molecular simulation and nuclear magnetic resonance techniques. The microscopic structure of the ILs and the solvation environment of water, including hydrogen bonding, were studied. Free-energies of solvation of water were obtained using perturbation methods, and the values agree with experimental observations. Self-diffusion coefficients and viscosity were computed and compared with nuclear magnetic resonance measurements and literature. Simulations predict slower dynamics when compared with experiment: diffusion coefficients are underpredicted, whereas viscosity is overpredicted. As such, simulation is consistent in a Stokes-Einstein sense. The trends in transport properties due to changing anion, to the presence of water and the effect of temperature are well predicted. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3523–3531, 2017
      PubDate: 2017-03-07T08:12:20.641107-05:
      DOI: 10.1002/aic.15690
       
  • A spatially-averaged two-fluid model for dense large-scale gas-solid flows
    • Authors: Simon Schneiderbauer
      Pages: 3544 - 3562
      Abstract: We present a spatially-averaged two-fluid model (SA-TFM), which is derived from ensemble averaging the kinetic-theory based TFM equations. The residual correlation for the gas-solid drag, which appears due to averaging, is derived by employing a series expansion to the microscopic drag coefficient, while the Reynolds-stress-like contributions are closed similar to the Boussinesq-approximation. The subsequent averaging of the linearized drag force reveals that averaged interphase momentum exchange is a function of the turbulent kinetic energies of both, the gas and solid phase, and the variance of the solids volume fraction. Closure models for these quantities are derived from first principles. The results show that these new constitutive relations show fairly good agreement with the fine grid data obtained for a wide range of particle properties. Finally, the SA-TFM model is applied to the coarse grid simulation of a bubbling fluidized bed revealing excellent agreement with the reference fine grid solution. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3544–3562, 2017
      PubDate: 2017-03-07T08:46:15.957647-05:
      DOI: 10.1002/aic.15684
       
  • Transport phenomena in Eccentric Cylindrical Coordinates
    • Authors: P. H. Gilbert; C. Saengow, A. J. Giacomin
      Pages: 3563 - 3581
      Abstract: Studies in transport phenomena have been limited to a select few coordinate systems. Specifically, Cartesian, cylindrical, spherical, Dijksman toroidal, and bipolar cylindrical coordinates have been the primary focus of transport work. The lack of diverse coordinate systems, for which the equations of change have been worked out, limits the diversity of transport phenomena problem solutions. Here, we introduce eccentric cylindrical coordinates and develop the corresponding equations of change (continuity, motion, and energy). This new coordinate system is unique, distinct from bipolar cylindrical coordinates, and does not contain cylindrical coordinates as a special case. We find eccentric cylindrical coordinates to be more intuitive for solving transport problems than bipolar cylindrical coordinates. Specific applications are given, in the form of novel exact solutions, for problems important to chemical engineers, in momentum, heat and mass transfer. We complete our analysis of eccentric cylindrical coordinates by using the new equations to solve one momentum, one energy, and one mass transport problem exactly. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3563–3581, 2017
      PubDate: 2017-03-09T19:28:32.128503-05:
      DOI: 10.1002/aic.15671
       
  • Role of free surface on gas-induced liquid mixing in a shallow vessel
    • Authors: Abdul Quiyoom; Vivek V. Buwa, S. K. Ajmani
      Pages: 3582 - 3598
      Abstract: The present work is carried out to understand the effect of free surface on liquid velocity distribution, dynamics and liquid phase mixing in a shallow basic oxygen furnace (BOF). Three-dimensional/transient Euler–Lagrange (EL) without/with volume-of-fluid (VOF) simulations of dispersed gas–liquid flow in a scaled-down model of the BOF were performed. For lower H/D ratios, EL simulations performed with no-slip and free-slip boundary conditions led to oscillatory plume behavior and higher liquid velocity regions which in turn led to lower mixing time. In contrast, EL + VOF simulations led to reduced meandering motion of bubble plumes and lower liquid velocities resulting in higher mixing times. Interestingly, the mixing time predicted using EL + VOF approach was found to be in a good agreement with the measurements. The results presented in this work show that free surface has a significant effect on dynamics of gas–liquid flow and liquid phase mixing for shallow vessels with H/D ≤ 0.5. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3582–3598, 2017
      PubDate: 2017-03-23T14:43:22.151608-05:
      DOI: 10.1002/aic.15697
       
  • Experimental investigations of non-Newtonian/Newtonian liquid-liquid flows
           in microchannels
    • Authors: Evangelia Roumpea; Maxime Chinaud, Panagiota Angeli
      Pages: 3599 - 3609
      Abstract: The plug flow of a non-Newtonian and a Newtonian liquid was experimentally investigated in a quartz microchannel (200-µm internal diameter). Two aqueous glycerol solutions containing xanthan gum at 1000 and 2000 ppm were the non-Newtonian fluids and 0.0046 Pa s silicone oil was the Newtonian phase forming the dispersed plugs. Two-color particle image velocimetry was used to obtain the hydrodynamic characteristics and the velocity profiles in both phases under different fluid flow rates. The experimental results revealed that the increase in xanthan gum concentration produced longer, bullet-shaped plugs, and increased the thickness of the film surrounding them. From the shear rate and viscosity profiles, it was found that the polymer solution was in the shear-thinning region while the viscosity was higher in the middle of the channel compared to the region close to the wall. Circulation times in the aqueous phase increased with the concentration of xanthan gum. © 2017 The
      Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 63: 3599–3609, 2017
      PubDate: 2017-03-27T10:40:43.530978-05:
      DOI: 10.1002/aic.15704
       
 
 
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