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  Subjects -> ENGINEERING (Total: 2246 journals)
    - CHEMICAL ENGINEERING (187 journals)
    - CIVIL ENGINEERING (178 journals)
    - ELECTRICAL ENGINEERING (100 journals)
    - ENGINEERING (1206 journals)
    - ENGINEERING MECHANICS AND MATERIALS (374 journals)
    - HYDRAULIC ENGINEERING (53 journals)
    - INDUSTRIAL ENGINEERING (61 journals)
    - MECHANICAL ENGINEERING (87 journals)

ENGINEERING (1206 journals)            First | 1 2 3 4 5 6 7 | Last

Showing 201 - 400 of 1205 Journals sorted alphabetically
CT&F Ciencia, Tecnologia y Futuro     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 3)
Dams and Reservoirs     Hybrid Journal   (Followers: 3)
Data Handling in Science and Technology     Full-text available via subscription   (Followers: 4)
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 24)
Designed Monomers and Polymers     Hybrid Journal  
Designs, Codes and Cryptography     Hybrid Journal   (Followers: 6)
Developments in Clay Science     Full-text available via subscription  
Developments in Geotechnical Engineering     Full-text available via subscription   (Followers: 3)
Developments in Mineral Processing     Full-text available via subscription   (Followers: 2)
Diálogos Interdisciplinares     Open Access  
Diamond Light Source Proceedings     Full-text available via subscription  
Diffusion Foundations     Full-text available via subscription  
Digital Signal Processing     Hybrid Journal   (Followers: 10)
Discrete Optimization     Full-text available via subscription   (Followers: 4)
Doct-Us Journal     Open Access  
Documents pour l'histoire des techniques     Open Access   (Followers: 1)
Dyes and Pigments     Hybrid Journal   (Followers: 1)
Dyna     Open Access  
Dynamical Systems : An International Journal     Hybrid Journal  
E&S Engineering and Science     Open Access  
El Hombre y la Máquina     Open Access  
Electromagnetics     Hybrid Journal   (Followers: 2)
Electrophoresis     Hybrid Journal   (Followers: 20)
Elementos     Open Access  
Elsevier Geo-Engineering Book Series     Full-text available via subscription   (Followers: 2)
Elsevier Ocean Engineering Series     Full-text available via subscription  
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 28)
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations     Open Access  
Energies     Open Access   (Followers: 3)
Energy and Power Engineering     Open Access   (Followers: 14)
Energy Conversion and Management     Hybrid Journal   (Followers: 8)
Energy Engineering     Full-text available via subscription   (Followers: 9)
Energy for Sustainable Development     Hybrid Journal   (Followers: 7)
Energy Procedia     Open Access   (Followers: 2)
Energy Science & Engineering     Open Access   (Followers: 4)
Energy Science and Technology     Open Access   (Followers: 14)
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects     Hybrid Journal   (Followers: 1)
Energy Sources, Part B: Economics, Planning, and Policy     Hybrid Journal   (Followers: 6)
Energy Systems     Hybrid Journal   (Followers: 13)
ENGEVISTA     Open Access   (Followers: 1)
ENGI : Revista Electrónica de la Facultad de Ingenieria     Open Access  
Engineer : Journal of the Institution of Engineers, Sri Lanka     Open Access  
Engineering     Open Access   (Followers: 1)
Engineering     Open Access   (Followers: 1)
Engineering & Technology     Hybrid Journal   (Followers: 20)
Engineering Analysis with Boundary Elements     Hybrid Journal   (Followers: 1)
Engineering Computations     Hybrid Journal   (Followers: 3)
Engineering Economics     Open Access   (Followers: 4)
Engineering Economist, The     Hybrid Journal   (Followers: 4)
Engineering Education     Open Access   (Followers: 1)
Engineering Failure Analysis     Hybrid Journal   (Followers: 56)
Engineering Geology     Hybrid Journal   (Followers: 6)
Engineering International     Open Access  
Engineering Journal     Open Access   (Followers: 1)
Engineering Management Journal     Hybrid Journal   (Followers: 18)
Engineering Management Research     Open Access   (Followers: 5)
Engineering Management Reviews     Open Access   (Followers: 1)
Engineering Optimization     Hybrid Journal   (Followers: 6)
Engineering Science and Technology, an International Journal     Open Access  
Engineering Sciences     Open Access  
Engineering Studies     Hybrid Journal  
Engineering With Computers     Hybrid Journal   (Followers: 6)
Engineering, Technology & Applied Science Research     Open Access  
Entramado     Open Access  
Entropy     Open Access   (Followers: 3)
Environmental & Engineering Geoscience     Full-text available via subscription   (Followers: 3)
Environmental and Ecological Statistics     Hybrid Journal   (Followers: 6)
Environmetrics     Hybrid Journal  
Épités - Épitészettudomány     Full-text available via subscription   (Followers: 1)
EPJ Photovoltaics     Open Access   (Followers: 3)
Épsilon     Open Access  
Ergonomics in Design: The Quarterly of Human Factors Applications     Hybrid Journal   (Followers: 12)
ESAIM: Control Optimisation and Calculus of Variations     Full-text available via subscription  
ESAIM: Mathematical Modelling and Numerical Analysis     Full-text available via subscription   (Followers: 4)
ESAIM: Proceedings     Open Access  
Estuaries and Coasts     Hybrid Journal   (Followers: 16)
European Journal of Combinatorics     Full-text available via subscription   (Followers: 3)
European Journal of Engineering Education     Hybrid Journal   (Followers: 3)
European Journal of Lipid Science and Technology     Hybrid Journal   (Followers: 1)
European Journal of Mass Spectrometry     Full-text available via subscription   (Followers: 17)
European Medical Device Technology     Full-text available via subscription   (Followers: 3)
European Physical Journal - Applied Physics     Full-text available via subscription   (Followers: 6)
European Transport Research Review     Open Access   (Followers: 21)
Evolutionary Intelligence     Hybrid Journal  
Evolving Systems     Hybrid Journal  
Exacta     Open Access  
Experimental Techniques     Hybrid Journal   (Followers: 54)
Experiments in Fluids     Hybrid Journal   (Followers: 7)
Fibers and Polymers     Full-text available via subscription   (Followers: 3)
Filtration & Separation     Full-text available via subscription   (Followers: 4)
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 4)
Fire Science Reviews     Open Access   (Followers: 5)
First Monday     Open Access   (Followers: 56)
Flexible Services and Manufacturing Journal     Hybrid Journal   (Followers: 1)
Flow, Turbulence and Combustion     Hybrid Journal   (Followers: 21)
Fluid Dynamics     Hybrid Journal   (Followers: 6)
Fluid Dynamics Research     Full-text available via subscription   (Followers: 8)
Fluid Phase Equilibria     Hybrid Journal   (Followers: 4)
Focus on Catalysts     Full-text available via subscription  
Focus on Pigments     Full-text available via subscription   (Followers: 3)
Focus on Powder Coatings     Full-text available via subscription   (Followers: 3)
Focus on Surfactants     Full-text available via subscription   (Followers: 2)
Food Engineering Reviews     Hybrid Journal   (Followers: 3)
Food Science and Technology     Open Access   (Followers: 3)
Formación Universitaria     Open Access   (Followers: 3)
FORMakademisk     Open Access  
Formal Methods in System Design     Hybrid Journal   (Followers: 6)
Forschung     Hybrid Journal  
Forschung im Ingenieurwesen     Hybrid Journal   (Followers: 1)
Foundations of Science     Hybrid Journal  
Frontiers in Aerospace Engineering     Open Access   (Followers: 7)
Frontiers in Energy     Hybrid Journal   (Followers: 4)
Frontiers in Geotechnical Engineering     Open Access   (Followers: 2)
Frontiers of Engineering Management     Open Access  
Frontiers of Environmental Science & Engineering     Hybrid Journal   (Followers: 4)
Frontiers of Nanoscience     Full-text available via subscription   (Followers: 1)
Fuel and Energy Abstracts     Full-text available via subscription   (Followers: 4)
Fuel Cells     Hybrid Journal   (Followers: 4)
Fuel Cells Bulletin     Full-text available via subscription   (Followers: 5)
Fusion Engineering and Design     Hybrid Journal   (Followers: 8)
Fuzzy Information and Engineering     Open Access   (Followers: 3)
Fuzzy Sets and Systems     Hybrid Journal   (Followers: 4)
Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards     Hybrid Journal   (Followers: 6)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 21)
Geotechnical Testing Journal     Full-text available via subscription   (Followers: 8)
Géotechnique     Hybrid Journal   (Followers: 11)
Geothermics     Hybrid Journal   (Followers: 4)
GeoWorld     Full-text available via subscription   (Followers: 2)
Glass Technology - European Journal of Glass Science and Technology Part A     Full-text available via subscription   (Followers: 3)
Global Journal of Engineering Research     Full-text available via subscription  
Global Perspective on Engineering Management     Open Access   (Followers: 1)
GPS Solutions     Hybrid Journal   (Followers: 10)
Graphs and Combinatorics     Hybrid Journal   (Followers: 6)
Grass and Forage Science     Hybrid Journal   (Followers: 6)
Great Circle: Journal of the Australian Association for Maritime History, The     Full-text available via subscription   (Followers: 7)
Handai Nanophotonics     Full-text available via subscription  
Handbook of Adhesives and Sealants     Full-text available via subscription   (Followers: 1)
Handbook of Sensors and Actuators     Full-text available via subscription   (Followers: 7)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 2)
Heat Exchangers     Open Access   (Followers: 1)
Heat Transfer - Asian Research     Hybrid Journal   (Followers: 7)
Heat Transfer Engineering     Hybrid Journal   (Followers: 14)
Historical Records of Australian Science     Hybrid Journal   (Followers: 2)
Human Factors in Ergonomics & Manufacturing     Hybrid Journal   (Followers: 5)
Iberoamerican Journal of Project Management     Open Access   (Followers: 3)
IBM Journal of Research and Development     Hybrid Journal   (Followers: 17)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 29)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 23)
IEEE Communications Magazine     Full-text available via subscription   (Followers: 42)
IEEE Control Systems Magazine     Full-text available via subscription   (Followers: 48)
IEEE Engineering Management Review     Full-text available via subscription   (Followers: 27)
IEEE Geoscience and Remote Sensing Letters     Hybrid Journal   (Followers: 21)
IEEE Industry Applications Magazine     Full-text available via subscription   (Followers: 16)
IEEE Instrumentation & Measurement Magazine     Full-text available via subscription   (Followers: 39)
IEEE Journal of Biomedical and Health Informatics     Hybrid Journal   (Followers: 11)
IEEE Journal of Oceanic Engineering     Hybrid Journal   (Followers: 9)
IEEE Journal of Selected Topics in Quantum Electronics     Hybrid Journal   (Followers: 7)
IEEE Journal of Selected Topics in Signal Processing     Hybrid Journal   (Followers: 22)
IEEE Journal of Solid-State Circuits     Full-text available via subscription   (Followers: 17)
IEEE Journal on Selected Areas in Communications     Hybrid Journal   (Followers: 11)
IEEE Latin America Transactions     Full-text available via subscription   (Followers: 2)
IEEE Microwave and Wireless Components Letters     Hybrid Journal   (Followers: 12)
IEEE Microwave Magazine     Full-text available via subscription   (Followers: 20)
IEEE Potentials     Full-text available via subscription   (Followers: 17)
IEEE Signal Processing Letters     Hybrid Journal   (Followers: 25)
IEEE Spectrum     Full-text available via subscription   (Followers: 97)
IEEE Technology and Society Magazine     Full-text available via subscription   (Followers: 2)
IEEE Transactions on Advanced Packaging     Full-text available via subscription   (Followers: 7)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 22)
IEEE Transactions on Applied Superconductivity     Hybrid Journal   (Followers: 2)
IEEE Transactions on Audio, Speech, and Language Processing     Hybrid Journal   (Followers: 12)
IEEE Transactions on Automation Science and Engineering     Full-text available via subscription   (Followers: 8)
IEEE Transactions on Circuits and Systems II: Express Briefs     Hybrid Journal   (Followers: 12)
IEEE Transactions on Components and Packaging Technologies     Full-text available via subscription   (Followers: 12)
IEEE Transactions on Control Systems Technology     Hybrid Journal   (Followers: 38)
IEEE Transactions on Education     Hybrid Journal   (Followers: 5)
IEEE Transactions on Electronics Packaging Manufacturing     Full-text available via subscription   (Followers: 16)
IEEE Transactions on Energy Conversion     Hybrid Journal   (Followers: 10)
IEEE Transactions on Engineering Management     Hybrid Journal   (Followers: 19)
IEEE Transactions on Evolutionary Computation     Hybrid Journal   (Followers: 8)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 14)
IEEE Transactions on Instrumentation and Measurement     Hybrid Journal   (Followers: 38)
IEEE Transactions on Intelligent Transportation Systems     Hybrid Journal   (Followers: 6)
IEEE Transactions on Knowledge and Data Engineering     Hybrid Journal   (Followers: 20)
IEEE Transactions on Magnetics     Hybrid Journal   (Followers: 7)
IEEE Transactions on Microwave Theory and Techniques     Hybrid Journal   (Followers: 15)
IEEE Transactions on Nuclear Science     Hybrid Journal   (Followers: 7)
IEEE Transactions on Plasma Science     Hybrid Journal   (Followers: 4)
IEEE Transactions on Power Delivery     Hybrid Journal   (Followers: 14)
IEEE Transactions on Professional Communication     Hybrid Journal   (Followers: 4)
IEEE Transactions on Reliability     Hybrid Journal   (Followers: 26)
IEEE Transactions on Robotics     Hybrid Journal   (Followers: 26)
IEEE Transactions on Semiconductor Manufacturing     Hybrid Journal   (Followers: 5)
IEEE Transactions on Signal Processing     Hybrid Journal   (Followers: 47)
IEEE Transactions on Vehicular Technology     Hybrid Journal   (Followers: 2)
IEEE Vehicular Technology Magazine     Full-text available via subscription   (Followers: 8)
IEEE/ACM Transactions on Computational Biology and Bioinformatics     Hybrid Journal   (Followers: 13)
IERI Procedia     Open Access  
IET Circuits, Devices & Systems     Hybrid Journal   (Followers: 17)

  First | 1 2 3 4 5 6 7 | Last

Journal Cover AIChE Journal
  [SJR: 1.098]   [H-I: 104]   [25 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0001-1541 - ISSN (Online) 1547-5905
   Published by John Wiley and Sons Homepage  [1598 journals]
  • Mathematical Modeling of a Moving Bed Reactor for Post‐Combustion
           CO2 Capture
    • Authors: Hosoo Kim; David C. Miller, Srinivasarao Modekurti, Benjamin Omell, Debangsu Bhattacharyya, Stephen E. Zitney
      Abstract: A mathematical model for a moving bed reactor with embedded heat exchanger has been developed for application to solid sorbent‐based capture of carbon dioxide (CO2) from flue gas emitted by coal‐fired power plants. The reactor model is one‐dimensional, non‐isothermal, and pressure‐driven. The two‐phase (gas and solids) model includes rigorous kinetics and heat and mass transfer between the two phases. Flow characteristics of the gas and solids in the moving bed are obtained by analogy with correlations for fixed and fluidized bed systems. From the steady‐state perspective, this work presents the impact of key design variables that can be used for optimization. From the dynamic perspective, the paper shows transient profiles of key outputs that should be taken into account while designing an effective control system. In addition, the paper also presents performance of a model predictive controller for the moving bed regenerator under process constraints. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-29T04:26:43.901492-05:
      DOI: 10.1002/aic.15289
       
  • Engineering model for intumescent coating behavior in a pilot‐scale
           gas‐fired furnace
    • Abstract: In the event of a fire, intumescent fire protective coatings expand and form a thermally insulating char that protects the underlying substrate from heat and subsequent structural failure. The intumescence includes several rate phenomena, which have been investigated and quantified in the literature for several decades. However, various challenges still exist. The most important one concerns mathematical model validation under realistic exposure conditions and/or time scales. Another is the simplification of advanced models to overcome the often‐seen lack of a complete set of input and adjustable model parameters for a given coating, thereby providing models for industrial applications. In this work, these two challenges are addressed. Three experimental series, with an intumescent coating inside a 0.65 m3 gas‐fired furnace, heating up according to so‐called cellulosic fire conditions, were conducted and a very good repeatability was evident. The experiments were run for almost three hours, reaching a final gas temperature of about 1100 °C. Measurements include transient temperature developments inside the expanding char, at the steel substrate, and in the mineral wool insulation placed behind the substrate. A mathematical model, describing the intumescent coating behavior and temperatures in the furnace using a single overall reaction was developed and validated against experimental data. By including a decomposition front movement through the char, a good qualitative agreement was obtained. After further validation against experiments with other coating formulations, it has potential to become a practical engineering tool. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-29T04:26:16.060791-05:
      DOI: 10.1002/aic.15291
       
  • A Novel Multiscale Approach for Rapid Prediction of Phase Behaviors with
           Consideration of Molecular Conformations
    • Abstract: The conformational distribution of flexible molecules may have a significant influence on its physical properties and phase behaviors. While atomistic molecular simulations naturally include conformational changes, they are often computationally expensive and require separate simulations for each state condition. On the other hand, an equation of state (EOS) provides a rapid description for a variety of fluid properties over the whole phase space; however, because of the ignorance of molecular structure, it is difficult to obtain the interaction parameters from first‐principles. Here we propose a multiscale approach for simultaneous predictions of fluid properties and molecular conformational distribution. The PR+COSMOSAC EOS is used to provide the fugacity of chemical species in a mixture. The electrostatic and dispersion interactions in the EOS are determined from quantum‐mechanical solvation calculations and molecular dynamics simulations at a few state points. The conformational transitions are considered as chemical reactions with the equilibrium constant determined from ab initio G4 calculations. With all the EOS parameters obtained from molecular simulations at different scales, subsequent phase equilibrium predictions can be achieved within milliseconds. We validated this approach using 1,2‐dichloroethane (DCE), whose dipole moment varies from 6.34 × 10−30 Cm in the gauche‐form to 0 in the trans‐form. Our results show that this approach provides not only accurate predictions for the vapor‐liquid and liquid‐liquid equilibrium of DCE‐containing fluids but also quantitative descriptions of conformational distribution of DCE in these systems. This novel method can be very useful for the prediction of thermodynamic properties of fluids with explicit inclusion of molecular conformations. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-29T04:25:49.573535-05:
      DOI: 10.1002/aic.15290
       
  • Numerical Modeling of the Cooling Cycle and Associated Thermal Stresses in
           a Melt Explosive Charge
    • Authors: Warren Sanhye; Charles Dubois, Isabelle Laroche, Pierre Pelletier
      Abstract: A comprehensive simulation tool is developed to describe and optimize the cooling cycle in the melt‐casting of Composition B. It comprises a multiphysics approach tackling heat, mass and momentum transfers involved in the casting process. The highly non‐linear solidification step and development of thermal stresses are included. A V & V (Verification and Validation) approach was adopted whereby the model was verified against a benchmark problem and tested with a simple cylindrical geometry. Then, the approach was applied to a 105 mm caliber artillery shell and simulation results were in close agreement with experimental measurements. The model is equipped with a CZM function to account for adhesion between the solidified cast and the mold. During cooling, separation is possible and the size and location of gaps, depending on shrinkage and adhesion, are successfully emulated. The importance of controlled solidification is pointed out, especially regarding steep temperature gradients within the shell. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-26T10:05:47.240841-05:
      DOI: 10.1002/aic.15288
       
  • Low‐temperature and highly efficient conversion of saccharides into
           formic acid under hydrothermal conditions
    • Authors: Jun Yun; Guodong Yao, Fangming Jin, Heng Zhong, Atsushi Kishita, Kazuyuki Tohji, Heiji Enomoto, Li Wang
      Abstract: Production of formic acid, which has been regarded as an important H2 carrier, from biomass can be a highly potential way to provide human societies with renewable energy source. To attain economically viable production of formic acid from biomass on an industrial scale, the system operation at low reaction temperature is crucially important. In this work, a low‐temperature hydrothermal conversion of carbohydrates such as monosaccharides and disaccharides into formic acid is reported. A good formic acid yield of 80–85% was obtained at a lower temperature of 423 K for only 15‐20 min in the presence of NaOH without any other catalyst. The alkali was found to act as two roles in enhancing the production of formic acid. One was inhibition of the formic acid decomposition; another was favorable for the oxidation selectively at C‐1 for aldoses, which leads to the formation of formic acid via the rupture of the C1–C2 bond. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-25T09:52:22.256438-05:
      DOI: 10.1002/aic.15287
       
  • Novel inexpensive transition metal phosphide catalysts for upgrading of
           pyrolysis oil via hydrodeoxygenation
    • Authors: Cheng Guo; Kasanneni Tirumala Venkateswara Rao, Ehsan Reyhanitash, Zhongshun Yuan, Sophia (Quan) He, Sohrab Rohani, Chunbao (Charles) Xu
      Abstract: Supported molybdenum/molybdenum‐phosphides as inexpensive catalysts for bio‐oil hydro‐de‐oxygenation (HDO) were in‐house prepared using different support materials, i.e., Al2O3, activated carbon (AC), MgAl2O4 and Mg6Al2(CO3)(OH)16. The HDO activity of these catalysts were investigated using a 100 mL bench‐scale reactor operating at 300 °C with an initial hydrogen pressure of 50 bar for 3 h with a pyrolysis oil. The catalytic efficiencies for bio‐oil HDO for the catalysts were compared with the expensive but commercially available Ru/C catalyst. Addition of small amount of P to the Mo catalysts supported on either AC and Al2O3 led to increased degree of deoxygenation (DOD) and oil yield compared with those without P. MoP supported on AC (MoP/AC) demonstrated bio‐oil HDO activity comparable to the Ru/C catalyst. Furthermore, three AC‐supported metal phosphides for pyrolysis oil HDO were compared under the same conditions, and they were found to follow the order of NiP/AC > CoP/AC > MoP/AC. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-25T09:52:12.155234-05:
      DOI: 10.1002/aic.15286
       
  • Covariance‐Based Hardware Selection Part IV: Solution Using the
           Generalized Benders Decomposition
    • Authors: Jin Zhang; Xiaoxi Wang, Donald J. Chmielewski
      Abstract: Recently the covariance based hardware selection problem has been shown to be of the Mixed Integer Convex Programming (MICP) class. While such a formulation provides a route to global optimality, use of the branch and bound search procedure has limited application to fairly small systems. The particular bottleneck is that during each iteration of the branch and bound search, a fairly slow Semi‐Definite Programming (SDP) problem must be solved to its global optimum. In this work, we illustrate that a simple reformulation of the MICP and subsequent application of the Generalized Benders Decomposition (GBD) algorithm will result in massive reductions in computational effort. While the resulting algorithm must solve multiple mixed integer linear programs, this increase in computational effort is significantly outweighed by the reduction in the number of SDP problems that must be solved. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-22T04:46:40.154406-05:
      DOI: 10.1002/aic.15285
       
  • A Novel Carbonized Polydopamine (C‐PDA) Adsorbent with High CO2
           Adsorption Capacity and Water Vapor Resistance
    • Authors: Shikai Xian; Feng Xu, Zhenxia Zhao, Qibin Xia, Jing Xiao, Yingwei Li, Haihui Wang, Zhong Li
      Abstract: Novel carbonized polydopamine adsorbents (C‐PDAs) with high surface area, high CO2 adsorption capacity and superior moisture resistance performance were prepared by one‐step synthesis method using polydopamine as carbon precursor at different KOH/C ratios, and then characterized. CO2 and water vapor adsorption performances of C‐PDAs were examined separately by static adsorption and fixed‐bed experiments. Results showed that BET area and pore volume of C‐PDA‐4 were up to 3342 m2/g and 2.01 cm3/g, respectively. Its CO2 adsorption capacity reached up to 30.5 mmol/g at 25 bar, much higher than many other adsorbents including MOFs. C‐PDAs prepared with high KOH/C ratios had low surface element concentrations of O and N resulting in low surface hydrophilic property. H2O(g) isotherm of C‐PDA was much lower than those on Mg‐MOF‐74, Cu‐BTC and MIL‐101(Cr). Fixed‐bed experiments showed that co‐presence of water vapor in feed stream with 30%RH had negligible impact on CO2 working capacity of C‐PDA. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-22T04:46:13.476988-05:
      DOI: 10.1002/aic.15283
       
  • A Hybrid Approach to Computing Electrostatic Forces in Fluidized Beds of
           Charged Particles
    • Authors: Jari Kolehmainen; Ali Ozel, Christopher M. Boyce, Sankaran Sundaresan
      Abstract: In particulate flow devices particles acquire electric charge through triboelectric charging, and resulting electrostatic forces can alter hydrodynamics. To capture this effect, the electrostatic force acting on individual particles in the device should be computed accurately. We present a hybrid approach to determine the electrostatic force, which finds the long‐range contribution to the electric field by solving the Poisson equation, estimates the short‐range contribution through truncated pairwise sum and adds a correction to avoid double counting. Euler‐Lagrange simulation of flows incorporating this hybrid approach reveals that bed height oscillations in small fluidized beds of particles with monopolar charge decreases with increasing charge level, which is related to lateral segregation of particles. A ring‐like layer of particles, reported in experimental studies, forms at modestly high charge levels. Beds with equal amounts of positively and negatively charged particles are fluidized in a manner similar to uncharged particles. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-22T04:45:46.633608-05:
      DOI: 10.1002/aic.15279
       
  • Control Structure Selection Based on Economics: Generalization of the
           back‐off Methodology
    • Authors: Ioannis K. Kookos; John D. Perkins
      Abstract: The back‐off methodology has been extensively developed and refined in the last 20 years and offers a systematic tool for solving the simultaneous design and control problem. Previous work has been based on linear process and control models that ensure quick determination of the optimal solution at the expense of potential loss in the accuracy due to nonlinear process characteristics. In this work a new formulation is proposed where use is made of a nonlinear process model that ensures improved accuracy and also offers an improved opportunity for the simultaneous consideration of process design and process control. Two case studies are studied in detail and demonstrate the advantages of the new formulation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-21T18:55:47.763052-05:
      DOI: 10.1002/aic.15284
       
  • Issue information
    • Abstract: Cover illustration. Understanding the propagation of variability using flowsheet modeling of the direct compaction line Photo courtesy of Sebastian Escotet, Dept. of Chemical Engineering, Rutgers University. 10.1002/aic.15210
      PubDate: 2016-04-20T08:51:56.902605-05:
      DOI: 10.1002/aic.14991
       
  • Characteristics and fouling propensity of polysaccharides in the presence
           of different monovalent ions
    • Authors: Xiang He; Fangang Meng, Anli Lin, Jiapeng Li, Chuyang Y. Tang
      Abstract: In this study the fouling behavior of alginate in the presence of monovalent ions (i.e., NaCl, KCl, CsCl, NaBr and NaI) was explored. Results showed that alginate tended to be less negatively charged in the presence of monovalent ions. The cation ion identity had a more substantial impact on the zeta potentials of alginate solution than the anion ion identity, which was likely due to preferential attraction between alginate and cation ion. Nevertheless, significantly increased particle size was observed for alginate in 150 mM CsCl, possibly arising from the specific interaction between alginate and Cs+. Membrane fouling was more severe for alginate in monovalent solutions, particularly at 150 mM ionic strength. The unified membrane fouling index was increased by cation and anion ions in the order of Na+ > K+ > Cs+ and Cl‐ > Br‐ > I‐, respectively. Nevertheless, the addition of monovalent ions could promote the fouling reversibility. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-20T04:01:56.672527-05:
      DOI: 10.1002/aic.15276
       
  • Drug release kinetics and mechanism from PLGA formulations
    • Abstract: The release kinetics of indomethacin (IND) and hydrochlorothiazide (HCT) from drug/PLGA formulations with different copolymer composition and molecular weight of PLGA were measured in vitro by using a rotating disk system (USP II). The release mechanism of IND and HCT from their PLGA formulations was analyzed using a chemical‐potential‐gradient model combined with the Perturbed‐Chain Statistical Associating Fluid Theory (PC‐SAFT). Furthermore, the release kinetics of IND and HCT from the PLGA formulations with different copolymer composition and molecular weight of PLGA were correlated and predicted in good accordance with the experimental data. It was found that the chemical‐potential‐gradient model combined with the PC‐SAFT helped to understand the drug release mechanism from the drug/PLGA formulations. It also well correlated and predicted the drug release kinetics as function of copolymer composition and molecular weight of PLGA as well as of drug type. It helps to save time and costs for determination of the long‐term drug release kinetics, especially for sustained drug release as obtained from the drug/PLGA formulations in this work. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-20T04:00:45.144879-05:
      DOI: 10.1002/aic.15282
       
  • Three‐component solids velocity measurements in the outlet section
           of a riser
    • Abstract: Coincident (simultaneous) three‐component particle velocity measurements performed using two Laser Doppler Anemometry (LDA) probes at the outlet section of a 9 m high cylindrical riser are for the first time presented for dilute flow conditions. Near the blinded extension of the T‐outlet a solids vortex is formed. Particle downflow along the riser wall opposite the outlet tube is observed, which is restricted to higher riser heights at higher gas flow rates. Increased velocity fluctuations are observed in the solids vortex and downflow region as well as at heights corresponding to the outlet tube. Contrary to the rest of the riser, in the downflow region time and ensemble velocity averages are not equal. Given the local bending of the streamlines, axial momentum transforms to radial and azimuthal momentum giving rise to the corresponding shear stresses. Turbulence intensity values indicate the edges of the downflow region. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-19T10:41:45.25215-05:0
      DOI: 10.1002/aic.15277
       
  • A soft‐sphere‐imbedded pseudo‐hard‐particle model
           for simulation of discharge flow of brick particles
    • Authors: Nan Gui; Xingtuan Yang, Jiyuan Tu, Shengyao Jiang
      Abstract: A novel hybrid approach of soft‐sphere‐imbedded pseudo‐hard‐particle model (SIPHPM) is proposed to cope with the complex collision of non‐spherical particles. In this approach, the boundary of a host hard particle is covered by a series of soft‐spheres, which are allowed to oscillate about the equilibrium position according to the position, orientation and shape configuration of the host particle. The collision processes are twofold: as a predictive process, particle‐particle interaction takes place through the collision between the distributed soft‐spheres, which causes sub‐spheres to deviate from the equilibrium positions; as a corrective process, relaxation is superposed to allow the soft‐spheres to move back toward the equilibrium positions quickly. Consequentially, this process generates the force and torque on the host particle and determines its movement. Finally, after validation, this new model is used to explore the effects of aspect ratio and base angle on the discharge of brick particles in hoppers. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-19T10:41:12.976906-05:
      DOI: 10.1002/aic.15278
       
  • Linking micro‐scale predictions of capillary forces to
           macro‐scale fluidization experiments in humid environments
    • Authors: Casey Q. LaMarche; Andrew W. Miller, Peiyuan Liu, Christine M. Hrenya
      Abstract: The effects of increasing relative humidity (RH) on fluidization/defluidization are investigated experimentally and understood via particle‐level predictions for the resulting capillary force. Experimentally, defluidization is found to be more sensitive to small changes in RH than fluidization. This sensitivity is captured by a new defluidization velocity Udf, which characterizes the curvature of the defluidization plot (pressure drop vs. velocity) observed between the fully‐fluidized (constant pressure drop) and packed‐bed (linear pressure drop dependence on velocity) states; this curvature is indicative of a partially‐fluidized state arising from humidity induced cohesion. Plots of Udf vs. RH reveal two key behaviors, namely Udf gradually increases with a relatively constant slope, followed by an abrupt increase at RH ∼55%. Furthermore, the bed transitions from Group A to Group C behavior between RH of approximately 60‐65%. From a physical standpoint, these macro‐scale trends are explained via a theory for capillary forces that, for the first time, incorporates measured values of particle surface roughness. Specifically, a model for the cohesive energy of rough surfaces in humid environments shows the same qualitative behavior as Udf vs. RH for RH
      PubDate: 2016-04-19T10:40:45.812807-05:
      DOI: 10.1002/aic.15281
       
  • Effect of needle‐like crystal shape on measured particle size
           distributions
    • Authors: Ian de Albuquerque; David R. Ochsenbein, Manfred Morari, Marco Mazzotti
      Abstract: The effect crystal morphology has on measured particle size distributions (PSDs) is ex‐plored, with a focus on particles exhibiting a needle‐like habit. An idealized in silico study was performed, targeted at modeling the measurement principles of various par‐ticle sizing devices, namely laser diffraction, Coulter counter, focused beam reflectance measurement, a single and a dual projection imaging devices. The evolution of a crystal population is measured, allowing for an evaluation of the introduced biases. Further, the consequences of these biases are highlighted by demonstrating how the real growth mechanism may be incorrectly interpreted depending on the chosen particle sizing tech‐nique. It is found that techniques which utilize a one‐dimensional PSD are incapable of simultaneously describing the concentration profile and average length; in contrast, imaging techniques are able to reproduce both quantities. Finally, the dual projection imaging device is shown to be the only instrument to yield a nearly bias‐free measure‐ment. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-18T02:51:38.409777-05:
      DOI: 10.1002/aic.15270
       
  • Product design: Metal nanoparticle‐based conductive inkjet inks
    • Authors: Sze Kee Tam; Ka Yip Fung, Grace Sum Hang Poon, Ka Ming Ng
      Abstract: A systematic procedure that provides an efficient workflow for formulating conductive inks is developed. Qualitative product attributes of the inkjet ink are first identified and transformed into quantitative product specifications. Ingredients are then selected based on heuristics, mechanistic and empirical models to meet the product specifications. Printability checks based on theoretical criteria are used to ensure that stable droplets can in principle be formed and coalesced properly to form a printed line of ink. Then, the conductive ink is prepared and printed to evaluate the performance of the inkjet ink experimentally. An example of preparing a copper ink for inkjet printing is used to illustrate the systematic procedure. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-18T02:51:12.448224-05:
      DOI: 10.1002/aic.15271
       
  • Nested direct transcription optimization for singular optimal control
           problems
    • Authors: Weifeng Chen; Lorenz T. Biegler
      Abstract: Singular optimal control problems arise frequently on a broad range of chemical engineering applications. Determination of the accurate dynamic structure of the optimal solution profile and the junctions between optimal nonsingular and singular arcs is essential for operating strategies, as well as equipment designs for many processes. In a previous study (Chen, Shao and Biegler, AIChE J 2014) we developed a nested optimization formulation that finds the optimal mesh distribution and determines exact control profiles for nonsingular optimal control problems without state constraints. This study extends this approach to singular optimal control problems. To satisfy the necessary optimality conditions for singular optimal control problems with a well‐defined solution strategy, the overall nonlinear programming formulation resulting from direct transcription is decomposed into inner and outer problems. The key feature of this algorithm is that it converges to a solution that satisfies the discretized Euler‐Lagrange equations of the original singular optimal control problem; we prove this under suitable assumptions. This is obtained through the introduction of pseudo‐multipliers that reconstruct the necessary optimality conditions for singular optimal control in the outer problem. We demonstrate this approach on eight classical singular control problems with known solutions, as well as three larger singular control problems derived from chemical engineering applications. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-18T02:50:47.48667-05:0
      DOI: 10.1002/aic.15272
       
  • Forced convection boiling in a stator‐rotor‐stator spinning
           disc reactor
    • Authors: M.M. de Beer; J.T.F. Keurentjes, J.C. Schouten, J. van der Schaaf
      Abstract: Boiling of a pure fluid inside the rotor‐stator cavities of a stator‐rotor‐stator spinning disc reactor (srs‐SDR) is studied, as a function of rotational velocity ω, average temperature driving force ΔT and mass flow rate φm. The average boiling heat transfer coefficient hb increases a factor 3 by increasing ω up to 105 rad s−1, independently of ΔT and φm. The performance of the srs‐SDR, in terms of hb versus specific energy input ε, is similar to tubular boiling, where pressure drop provides the energy input. The srs‐SDR enables operation at ε >105 WR−3, yielding values of hb not practically obtainable in passive evaporators, due to prohibitively high pressure drops required. Since hb is increased independently of the superficial vapour velocity, hb is not a function of φm and the local vapour fraction. Therefore, the srs‐SDR enables a higher degree of control and flexibility of the boiling process, compared to passive flow boiling. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-11T08:40:43.279581-05:
      DOI: 10.1002/aic.15274
       
  • Convective condensation in a stator‐rotor‐stator spinning disc
           reactor
    • Authors: M.M. de Beer; J.T.F. Keurentjes, J.C. Schouten, J. van der Schaaf
      Abstract: Centrifugal intensification of condensation heat transfer in the rotor‐stator cavities of a stator‐rotor‐stator spinning disc reactor (srs‐SDR) is studied, as a function of rotational velocity ω, volumetric throughflow rate φ and average temperature driving force ΔT. For the current range of ω, heat transfer from the vapour bubbles to the condensate liquid is limiting, due to a relatively low gas‐liquid interfacial area aGL. For ω > 84 rad s−1, a strong increase of aGL, results in increasing the reactor‐average condensation heat transfer coefficient hc from 1600 to 5600 Wm−2K−1, for condensation of pure dichloromethane vapour. Condensation heat transfer in the srs‐SDR is enhanced by rotation, independent of the vapour velocity. The intensified condensation comes at the cost of relatively high energy dissipation rates, indicating condensation in the srs‐SDR is more suited as a means to supply heat (e.g. in an intensified reactor‐heat exchanger), rather than for bulk cooling purposes. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-11T08:26:12.528435-05:
      DOI: 10.1002/aic.15275
       
  • Transport and deposition kinetics of polymer‐coated multiwalled
           carbon nanotubes in packed beds
    • Authors: Ngoc H. Pham; Changlong Chen, Benjamin Shiau, Jeffrey H. Harwell, Daniel E. Resasco, Dimitrios V. Papavassiliou
      Abstract: In this study, a modified filtration equation that accounts for the transport and kinetics of polymer‐coated multiwalled carbon nanotubes in columns packed with crushed Berea sandstone is presented. The columns were saturated with brine solution, in which the salt concentration was varied from 0 to 10wt%. Experimental results show that the polymer effectively eliminates the effects of salt on particle deposition when the salt concentration is less than or equal to 10wt%. The calculated cumulative particle recovery is as high as 88.47 ± 0.25%. Results show that, at 10wt% salt concentration, the proposed equation successfully predicts the experimental behavior, especially at the early stages of the breakthrough, where commonly used models fail. It is argued that the new equation accounts for the dynamic change of single collector efficiency as the deposition process advances. When tested against prior results available in the literature, the proposed model agrees with published data from other investigators. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-11T08:25:46.677047-05:
      DOI: 10.1002/aic.15273
       
  • On thermodynamic separation efficiency: Adsorption processes
    • Authors: Ryan P. Lively; Matthew J. Realff
      Abstract: This article presents a simplified thermodynamic analysis of adsorption processes in temperature swing adsorption (TSA) and pressure swing adsorption (PSA) modes as a function of adsorbate concentration and the adsorbent‐adsorbate interaction strength. The thermodynamic separation efficiency of a TSA process is optimal at dilute feed conditions, and becomes more thermodynamically efficient with increasing adsorbate affinity even though the energy of separation increases. The adsorption process is spontaneous, and for a strong isotherm, the energy required to reverse the adsorption is nearly independent of the adsorbate concentration as adsorbate loading in nearly‐saturated materials is essentially constant with feed concentration. PSA units are efficient thermodynamically and the efficiency increases with the concentration of the desired adsorbate. This thermodynamic treatment has implications for separation processes that address carbon emissions. TSA systems operate more efficiently (thermodynamically) in the “air capture” case because they apply work to the concentrated product rather than the dilute feed. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-06T10:36:51.328242-05:
      DOI: 10.1002/aic.15269
       
  • A Review of the Operating Limits in Slot Die Coating Processes
    • Authors: Xiaoyu Ding; Jianhua Liu, Tequila A.L. Harris
      Abstract: Slot die coating is a pre‐metered process commonly used for producing thin and uniform films. It is an important film fabrication method for applications where precise coating is required. A major concern in slot die coating processes is how to determine the operating limits to set the appropriate range of operating parameters, including coating speed, flow rate, vacuum pressure, coating gap, liquid viscosity and surface tension, etc. Operating limits directly determine the effectiveness and efficiency of the process. In this paper, the current state of academic research on operating limits in slot die coating processes is reviewed. Specifically, the theories, mechanisms, and empirical conclusions related to the limits on vacuum pressure, the low‐flow limit, the limit of wet thickness for zero‐vacuum‐pressure cases, the limit of dynamic wetting failure, and the limits of coating speed for a specific flow rate are reviewed. The paper concludes with some recommendations for future work. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-06T10:36:27.394755-05:
      DOI: 10.1002/aic.15268
       
  • Impact of Problem Formulation on LNG Process Optimization
    • Abstract: The power consumption of a single mixed‐refrigerant process (PRICO®) for natural gas liquefaction was minimized using four different constraint formulations to handle the trade‐off between investment and operating costs. Aspen HYSYS® was used for process simulation, while a sequential quadratic programming algorithm (NLPQLP) was used for optimization. The results confirm that optimal utilization of the heat exchanger area is only obtained with a constraint based on a maximum heat exchanger conductance (UA). The minimum temperature difference constraint commonly used in process design gives a significant energy penalty as it is incapable of accounting for the distribution of driving forces with respect to temperature, the non‐linearity of the composite curves and the trade‐off between driving forces and cooling load. The results also indicate that the maximum heat exchanger conductance constraint leads to increased complexity of the optimization problem, and that the success rate of the optimization method used therefore is reduced. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-05T06:23:52.782685-05:
      DOI: 10.1002/aic.15266
       
  • Counter‐Current Droplet‐Flow‐Based Mini Extraction with
           Pulsed Feeding and without Moving Parts
    • Authors: Cong Xu; Shan Jing, Yifeng Chu
      Abstract: his article describes a counter‐current arrangement of immiscible liquid‐liquid mini contactors based on droplets. Mini mixers without any moving parts were used as the contactors. The single stage mini mixer consists of a top and bottom mixing chamber. Both of the mixing chambers have two recirculating channels on either side. In these mini mixers, a liquid was broken up into droplets that dispersed into other continuously flowing liquid, consequently achieving a mass transfer between the two liquids. To realize the counter‐current arrangement, the two liquids were alternately fed into the system from opposite ends by compressed air according to a periodic program. One period consists of the following stages: organic phase feeding stage, droplet aggregation stage I, aqueous phase feeding stage, and droplet aggregation stage II. This continuous counter‐current arrangement is without the defects of continuous counter‐current arrangements based on laminar flows and multiple‐stage counter‐current arrangements based on droplets. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-05T06:23:13.015685-05:
      DOI: 10.1002/aic.15267
       
  • Non‐Intrusive Characterization of Particle Size Changes in Fluidized
           Beds Using Recurrence Plots
    • Abstract: An on‐line method is developed for monitoring of mean particle size in fluidized beds using pressure fluctuations (PF) and acoustic emissions (AE) signal by recurrence plot (RP) and recurrence quantification analysis (RQA). PFs and AE signals of a lab‐scale fluidized bed were measured simultaneously at various superficial gas velocities and mean particle sizes. Although the AE signals are often very complicated due to many different acoustic sources in the bed, applying RP analyses showed that small changes in mean particle size can be detected by visual comparison of AE‐RP structures, while this cannot be distinguished by graphical RP analysis of PFs. Moreover, the hydrodynamics of the bed was inspected through RQA analysis of both signals. For this purpose, recurrence rate, determinism, laminarity, average length of diagonal and vertical lines were extracted from RPs showing the effect of an increase in the mean particle size. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-05T06:21:40.869971-05:
      DOI: 10.1002/aic.15265
       
  • Functionalized Metal‐Organic Polyhedra Hybrid Membranes for Aromatic
           Hydrocarbons Recovery
    • Abstract: Pervaporation membranes are potentially useful in the separation of aromatic/aliphatic mixtures. Wherein, the membrane material plays a key role. Herein, a series of functionalized metal‐organic polyhedra (MOPs)/hyperbranched polymer hybrid membranes are molecularly designed and fabricated for the recovery of aromatic hydrocarbons. The isostructural MOP molecules with different functional groups are uniform in shape/size and soluble in solvents, which enable them to disperse well and be compatible in/with the polymer. Pervaporation results demonstrated significant improvements of these membranes in separation performances. Particularly, the membrane with MOP‐SO3NanHm showed the separation factor of 8.03 and the permeation flux of 528 g/m2h for the recovery of toluene from its 50 wt.% n‐heptane mixture, and those values are 8.4 and 540 g/m2h for benzene/cyclohexane mixture. We propose that the selectivity of these membranes is affected primarily by the polarity of functional groups in MOPs, which were further explained by the adsorption experiments and molecular simulations. This article is protected by copyright. All rights reserved. Functional metal‐organic polyhedra (MOPs)‐based hybrid membranes were fabricated by a method of plugging the pores within the ceramic substrate, which represented good separation performances towards aromatic/aliphatic hydrocarbons mixtures. It was found that the polarity of the functional groups in the MOPs has great effect on the separation performances of their hybrid membranes.
      PubDate: 2016-03-31T11:22:32.343005-05:
      DOI: 10.1002/aic.15263
       
  • Fast Access to Core/Shell/Shell CdTe/CdSe/ZnO Quantum Dots via Magnetic
           Hyperthermia Method
    • Abstract: The intrinsic low quantum yield (QY) of type II core shell quantum dots (QDs) composes the limitation for these heterostructured nanomaterials to be used in practical application. Herein, magnetic hyperthermia method is employed to intensify reaction process and facilely synthesize CdTe/CdSe heterostructured quantum dots with improved optical performance for the first time. The QY of the type II QDs was increased to 49% by further growing an inert ZnO layer. The type I interface between CdSe and ZnO help confine electrons to the inner structure of the QDs, thus improving the QY. The successful preparation and performance enhancement of the CdTe/CdSe type II QDs via magnetic hyperthermia method demonstrates the great potential of this method the preparation of other materials. Besides, the red‐emission QDs are used as conversion materials in white light emitting diodes (LEDs) to reveal their promising application in practical illumination. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-31T11:21:33.445932-05:
      DOI: 10.1002/aic.15264
       
  • LES–Lagrangian‐particles‐simulation of turbulent
           reactive flows at high Sc number using approximate deconvolution model
    • Authors: T. Watanabe; K. Nagata
      Abstract: Large eddy simulation (LES) with the approximate deconvolution model (ADM) is combined with Lagrangian particles simulation (LPS) for simulating turbulent reactive flows at high Schmidt numbers Sc. The LES is used to simulate velocity and nonreactive scalar while reactive scalars are simulated by the LPS using the mixing volume model for molecular diffusion. The LES–LPS is applied to turbulent scalar mixing layers with a second‐order isothermal irreversible reaction at Sc = 600. The mixing volume model is implemented with the IEM, Curl's, and modified Curl's mixing schemes. The mixing volume model provides a correct decay rate of nonreactive scalar variance at high Sc independently of the number of particles. The statistics in the LES–LPS with the IEM or modified Curl's mixing scheme agree well with the experiments for both moderately‐fast and rapid reactions. However, the LPS with the Curl's mixing scheme overpredicts the effects of the rapid reaction. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-30T18:27:33.445664-05:
      DOI: 10.1002/aic.15261
       
  • Optimal placement of gas detectors: A P‐median formulation
           considering dynamic nonuniform unavailabilities
    • Abstract: A stochastic programming formulation (SPqt), based on the P‐median problem (PMP), is proposed for determining the optimal placement of detectors in mitigation systems while considering nonuniform dynamic detector unavailabilities. Unlike previously proposed formulations, SPqt explicitly considers backup detection levels. This allows the modeller to determine the maximum degree of the nonlinear products to be used based on the trade‐off between computational complexity and solution accuracy. We analyze this trade‐off on formulation SPqt results by using 4 real data sets for the gas detector placement problem while using unavailability values obtained from real industry gas detector data. For this data, our results show that two detection levels are sufficient to find objective values within 1% of the optimal solution. Using two detection levels reduces the nonlinear formulation to a quadratic formulation. Three solution strategies are proposed for this quadratic formulation and then compared from the computational efficiency perspective. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-30T18:27:02.597951-05:
      DOI: 10.1002/aic.15259
       
  • Size effects of graphene oxide on mixed matrix membranes for CO2
           separation
    • Authors: Jie Shen; Mengchen Zhang, Gongping Liu, Kecheng Guan, Wanqin Jin
      Abstract: Graphene oxide (GO)‐polyether block amide (PEBA) mixed matrix membranes were fabricated and the effects of GO lateral size on membranes morphologies, microstructures, physicochemical properties and gas separation performances were systematically investigated. By varying the GO lateral sizes (100–200 nm, 1–2 μm and 5–10 μm), the polymer chains mobility, as well as the length of the gas channels could be effectively manipulated. Among the as‐prepared membranes, a GO‐PEBA mixed matrix membrane (GO‐M‐PEBA) containing 0.1 wt% medium‐lateral sized (1–2 μm) GO sheets showed the highest CO2 permeation performance (CO2 permeability of 110 Barrer and CO2/N2 mixed gas selectivity of 80), which transcends the Robeson upper bound. Also, this GO‐PEBA mixed matrix membrane exhibited high stability during long‐term operation testing. Optimized by GO lateral size, the developed GO‐PEBA mixed matrix membrane shows promising potential for industrial implementation of efficient CO2 capture. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-30T18:26:28.932675-05:
      DOI: 10.1002/aic.15260
       
  • Intensification of photocatalytic pollutant abatement in microchannel
           reactor using TiO2 and TiO2‐graphene
    • Abstract: A microfluidic device was applied to the photocatalytic degradation of methylene blue as a model pollutant. Titanium dioxide nanoparticles (TiO2–P25) and a synthesized composite TiO2‐graphene catalyst were immobilized on the inner walls of a borosilicate glass microfluidic chip. The deposition evolution of the nanoparticles was evaluated by monitoring the optical profile of the system. It was found that a higher initial reaction rate was obtained in the microreactor containing composite catalyst (TiO2‐GR) on the inner walls, but both systems (TiO2 and TiO2‐GR) achieved similar reaction rates when the steady‐state was reached. Decolourization rate of methylene blue in our microfluidic chips was found to be approximately one order of magnitude higher than equivalent macroscopic systems reported in the literature at similar experimental conditions. Additionally, computational simulations were performed to investigate the physics involved in these processes. The model was experimentally validated for further scale‐out studies. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-30T18:25:55.897229-05:
      DOI: 10.1002/aic.15262
       
  • Efficient separation of N2 and He at low temperature using MFI membranes
    • Authors: Pengcheng Ye; Mattias Grahn, Danil Korelskiy, Jonas Hedlund
      Abstract: Ultra‐thin MFI membranes were evaluated for N2/He separation over the temperature range of 85–260 K for the first time. The membranes were rather nitrogen selective at all the conditions investigated. A highest N2/He selectivity of 75.7 with a high N2 flux of 83 kg m−2 h−1 was observed at 124 K. The separation was attributed to adsorption selectivity to N2, effectively hindering the transport of He in the zeolite pores. The exceedingly high permeance even at low temperatures was ascribed to the ultra‐thin (< 1µm) membrane used. As the pressure ratios increased, a better separation performance was obtained. A mathematical model showed the largest difference of adsorbed loading over the film at ca. 120 K was the main reason for the observed maximum selectivity. Further, the modelling indicated the selectivity would increase 2‐3 times by reducing the influence of defects, concentration polarisation and pressure drop over the support. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-29T18:16:52.078004-05:
      DOI: 10.1002/aic.15258
       
  • Optimal supply chain design and operations under multi‐scale
           uncertainties: Nested stochastic robust optimization modeling framework
           and solution algorithm
    • Authors: Dajun Yue; Fengqi You
      Abstract: Although strategic and operational uncertainties differ in their significance of impact, a “one‐size‐fits‐all” approach has been typically used to tackle all types of uncertainty in the optimal design and operations of supply chains. In this work, we propose a stochastic robust optimization model that handles multi‐scale uncertainties in a holistic framework, aiming to optimize the expected economic performance while ensuring the robustness of operations. Stochastic programming and robust optimization approaches are integrated in a nested manner to reflect the decision maker's different levels of conservativeness towards strategic and operational uncertainties. The resulting multi‐level mixed‐integer linear programming model is solved by a decomposition‐based column‐and‐constraint generation algorithm. To illustrate the application, a county‐level case study on optimal design and operations of a spatially‐explicit biofuel supply chain in Illinois is presented, which demonstrates the advantages and flexibility of the proposed modeling framework and efficiency of the solution algorithm. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-29T18:16:21.624575-05:
      DOI: 10.1002/aic.15255
       
  • Modeling and performance prediction of chromate reduction by iron oxide
           coated sand (IOCS) in adsorber reactors
    • Authors: Ryan Thacher; Varadarajan Ravindran, Massoud Pirbazari
      Abstract: This study investigated iron oxide coated sand (IOCS) as an adsorbent medium for removing hexavalent chromium (Cr(VI)) from industrial wastewater, as well as in permeable reactive barriers (PRBs) for remediation of Cr(VI) in aquifers. An important feature was the use of a mathematical model to forecast performance of IOCS fixed‐bed adsorber systems for Cr(VI) removal. Another significance aspect was the elucidation of IOCS surface mechanisms and interactions responsible for Cr(VI) sorption and reduction to the less toxic Cr(III). The adsorption equilibrium and mass‐transfer parameters for modeling were obtained from independent laboratory studies. Adsorber studies validated the predictive model and established the effectiveness of IOCS for Cr(VI) removal under different conditions. Model simulation studies demonstrated that adsorbent capacity, surface diffusion, and film transfer significantly influenced process dynamics. The study showed that IOCS can be used to remove Cr(VI) from contaminated waters, meeting the overall objectives of regulatory agencies. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-29T18:15:50.452133-05:
      DOI: 10.1002/aic.15257
       
  • Interfacial Phenomena and Droplet Size of Particle Stabilized Emulsions in
           Oscillatory Shear
    • Authors: H. G. Gomaa; R. Sabouni
      Abstract: Production of particle stabilized oil in water emulsions has been investigated both theoretically and experimentally under oscillatory shear conditions using different stabilizing particles (SPs). The investigation included analysis of the interaction between particles interfacial stability and droplets breakage and coalescence. For hydrophobic SPs, droplets maintained their sizes as determined by torque balance (TB) without significant breakage or coalescence. For the more hydrophilic SPs, larger droplets formed that broke by eddies in the inertial subrange. At higher fluid shear stresses, loss of the SPs occurred during droplet formation leading to near bare droplet surface and coalescence to much larger sizes with subsequent fragmentation by capillary instabilities. The final droplet size in both cases was very different from TB model predictions. A modeling approach is proposed that combined both TB and droplet breakage and coalescence mechanisms. Comparison between the experimental results and the models predictions showed satisfactory agreement. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-29T03:10:46.671946-05:
      DOI: 10.1002/aic.15256
       
  • An analytical model for real gas flow in shale nanopores with
           non‐circular cross‐section
    • Authors: Wenxi Ren; Gensheng Li, Shouceng Tian, Mao Sheng, Xin Fan
      Abstract: An analytical model for gas transport in shale media is proposed on the basis of the linear superposition of convective flow and Knudsen diffusion, which is free of tangential momentum accommodation coefficient (TMAC). The present model takes into the effect of pore shape and real gas, and is successfully validated against experimental data and Lattice‐Boltzmann simulation results. Gas flow in non‐circular nanopores can be accounted by a dimensionless geometry correction factor. In continuum‐flow regime, pore shape has a relatively minor impact on gas transport capacity; the effect of pore shape on gas transport capacity enhances significantly with increasing rarefaction. Additionally, gas transport capacity is strongly dependent of average pore size and streamline tortuosity. We also show that the present model without using weighted factor can describe the variable contribution of convective flow and Knudsen diffusion to the total flow. As pressure and pore radius decrease, the number of molecule‐wall collisions gradually predominates over the number of inter‐molecule collisions, and thus Knudsen diffusion contributes more to the total flow. The parameters in the present model can be determined from independent laboratory experiments. We have the confidence that the present model can provide some theoretical support in numerical simulation of shale gas production. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-28T18:45:47.040089-05:
      DOI: 10.1002/aic.15254
       
  • CO2 sorption performance by aminosilane functionalized spheres prepared
           via Co‐condensation and post‐synthesis methods
    • Authors: David Madden; John P. Hanrahan, Joseph Tobin, Teresa Curtin
      Abstract: Amine functionalized silica microspheres were synthesised via a modified Stöber reaction for CO2 adsorption. A number of adsorbents were synthesized by co‐condensation and post synthesis immobilization of amines on porous silica spheres. CO2 adsorption studies were carried out on a fixed bed gas adsorption rig with online mass spectrometry. Amine co‐condensed silica spheres were found to adsorb up to 66 mg CO2 g−1 solid in a 0.15 atm CO2 stream at 35°C. Simple post‐synthesis addition of aminopropyltriethoxysilane (APTES) to amine co‐condensed silica was found to significantly increase the uptake of CO2 to 211 mg CO2 g−1 under similar conditions, with CO2 desorption commencing at temperatures as low as 60°C. The optimum temperature for adsorption was found to be 35°C. This work presents a CO2 adsorbent prepared via a simple synthesis method, with a high CO2 adsorption capacity and favorable CO2 adsorption/desorption performance under simulated flue gas conditions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-25T03:16:13.987789-05:
      DOI: 10.1002/aic.15253
       
  • Supercritical water gasification of aqueous fraction of pyrolysis oil in
           the presence of a Ni‐Ru catalyst
    • Authors: Izad Behnia; Zhongshun Yuan, Paul Charpentier, Chunbao (Charles) Xu
      Abstract: This study demonstrated that aqueous fraction of pyrolysis oil can be efficiently gasified into fuel gases methane and hydrogen via supercritical water gasification (SCWG) at moderate temperatures (500‐700 °C) over Ni20%Ru2%/γ‐Al2O3 catalyst. All experiments were performed in a bench‐scale continuous down‐flow tubular reactor packed with the catalyst. Carbon gasification efficiency of 0.91 mol/mol‐C (converted into CH4 and CO2) was achieved in SCWG of the aqueous fraction of pyrolysis oil (containing 2.98 wt. % C) at 700°C in the presence of the catalyst. A similar carbon gasification efficiency (approx. 0.89 mol/mol‐C) was obtained at a lower temperature (600 °C) with a diluted feedstock (0.7 wt. % C). SEM‐EDX and ICP analysis results confirmed that that this catalyst was stable during SCWG of aqueous fraction of pyrolysis oil after 6 hours on‐stream. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-25T03:15:44.905556-05:
      DOI: 10.1002/aic.15252
       
  • Property Prediction of Crystalline Solids from Composition and Crystal
           Structure
    • Authors: Bruno A. Calfa; John R. Kitchin
      Abstract: We propose using kernel regression as a data‐driven and rigorous nonparametric statistical technique to predict properties of atomic crystals. A key feature of the proposed approach is the possibility of treating predictors not only as continuous, but also as categorical data. The latter specifically allows the predictive model to capture the discrete nature of crystals with regards to composition (number of atoms in the chemical formula) and spatial configuration (finite number of crystallographic space groups). Another important aspect of using kernel regression is the direct access to its explicit mathematical form, which can be directly embedded in optimal inverse problems to design new crystalline materials with given target properties. The property prediction approach is illustrated by training models to predict electronic properties of 746 binary metal oxides and elastic properties of 1,173 crystals. As a first approach to solving the inverse problem, we describe an exhaustive enumeration algorithm. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-23T17:57:37.570433-05:
      DOI: 10.1002/aic.15251
       
  • Molecular Origin of Decreased Diffusivity with Loading for Benzene/HY
    • Authors: Huimin Zheng; Liang Zhao, Jingjing Ji, Qing Yang, Haokai Huang, Jinsen Gao
      Abstract: On the basis of our recently proposed “ideal” and “insertion” adsorption mechanisms of aromatics in HY zeolites, changes in energetic and dynamic properties with loading were investigated through Monte Carlo (MC) and Molecular Dynamic (MD) calculations. Loading‐dependent isosteric heat could be divided into three linear ranges. The two inflection points were attributed to adsorbate interactions and inherent adsorption mechanism changes. With regard to the loading dependence of diffusivity, diffusivity decreased faster at high loadings than at low and medium loadings, separated by an inflection point. This result confirmed a two‐stage diffusion mechanism based on the distribution of adsorbate from MD simulations which was able to qualitatively predict the further restriction of the mobility. This study provided insights into the modeling of mobility at high loadings on the basis of site‐hopping mechanism. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-23T17:57:09.884357-05:
      DOI: 10.1002/aic.15249
       
  • Dual‐bed Catalyst System for the Direct Synthesis of High Density
           Aviation Fuel with Cyclopentanone from Lignocellulose
    • Authors: Xueru Sheng; Guangyi Li, Wentao Wang, Yu Cong, Xiaodong Wang, George W. Huber, Ning Li, Aiqin Wang, Tao Zhang
      Abstract: In this paper, we demonstrated an integrated process for the direct production of tri(cyclopentane) with cyclopentanone which can be obtained from lignocellulose. The reaction was carried out in a dual‐bed continuous flow reactor. In the first bed, cyclopentanone was selectively converted to 2,5‐dicyclopentylcyclopentanol over the Pd‐MgAl‐HT (hydrotalcite) catalyst. Under solvent‐free and mild conditions (443 K, 0.1 MPa H2), high carbon yield (81.2%) of 2,5‐dicyclopentylcyclopentanol was achieved. Subsequently, the 2,5‐dicyclopentylcyclopentanol was further hydrodeoxygenated to tri(cyclopentane) in the second bed. Among the investigated catalysts, the Ni‐Hβ‐DP prepared by deposition‐precipitation (DP) method exhibited the highest activity for the hydrodeoxygenation step. By using Pd‐MgAl‐HT as the first bed catalyst and Ni‐Hβ‐DP as the second bed catalyst, tri(cyclopentane) was directly produced at high carbon yield (80.0%) with cyclopentanone as feedstock. This polycycloalkane has high density (0.91 kg/L) and can be used as additive to improve the density and volumetric heating value of bio‐jet fuel. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-23T17:56:40.651111-05:
      DOI: 10.1002/aic.15248
       
  • A Molecular Design Method Based on the COSMO‐SAC Model for Solvent
           Selection in Ionic Liquid Extractive Distillation
    • Authors: Jing Fang; Rui Zhao, Weiyi Su, Chunli Li, Jing Liu, Bo Li
      PubDate: 2016-03-23T17:56:14.026638-05:
      DOI: 10.1002/aic.15247
       
  • Statistics of droplet sizes generated by a microfluidic device
    • Abstract: The distribution of droplet sizes produced in a microfluidic T‐junction is modeled using the gamma probability distribution. The proposed model is validated using physical insight from the hypothesized mechanism of droplet breakup and statistically using the Anderson‐Darling test. Where signal‐to‐noise ratio is low and the gamma distribution does not hold, an alternative probabilistic description is used to estimate the true mean of droplet sizes. In addition, a new correlation is developed to relate mean droplet sizes to T‐junction inlet flow rates and dispersed‐phase viscosity. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-23T17:55:47.092649-05:
      DOI: 10.1002/aic.15246
       
  • Oxygen transport kinetics of MIEC membranes coated with different
           catalysts
    • Authors: Yan Liu; Xuefeng Zhu, Mingrun Li, Yue Zhu, Weishen Yang
      Abstract: Oxygen permeation through mixed ionic‐electronic conducting (MIEC) membrane may be controlled by oxygen bulk diffusion and/or oxygen interfacial exchange kinetics. In this paper, we chose BaCe0.05Fe0.95O3‐δ (BCF) as a representative to study the oxygen transport resistances of the membrane coated by different porous catalysts, including BCF itself, Ba0.5Sr0.5Co0.8Fe0.2O3‐δ (BSCF) and Sm0.5Sr0.5CoO3‐δ (SSC). The oxygen transport resistances of bulk, gas‐solid interfaces of feed‐side and sweep‐side of the catalyst‐coated membranes can be separately obtained through a linear regression of experimental data according to an oxygen permeation model. The three resistances of the membrane coated with BCF catalyst are smaller than those of the membrane coated with BSCF and SSC catalysts, though BSCF catalyst itself has the fastest bulk diffusion and interfacial exchange kinetics. The catalytic activities of BSCF and SSC catalysts on BCF membranes are impacted by the transport kinetics of catalysts, microstructure of catalyst layers and cationic inter‐diffusion between the membrane and catalysts. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-18T10:41:52.846212-05:
      DOI: 10.1002/aic.15239
       
  • Optimization and Simulation of the Sabatier Reaction Process in a Packed
           Bed
    • Authors: Baolin Hou; Yanqiang Huang, Xiaodong Wang, Xiaofeng Yang, Hongming Duan, Tao Zhang
      Abstract: The Sabatier reaction in a testing packed bed was investigated experimentally and theoretically, and was used to convert waste carbon dioxide and hydrogen to provide needed water for closing the life‐support loop on orbit in space. A three‐dimensional model including fluid flow, gas dispersion, heat and mass transfer and chemical reaction was developed by coupling some semi‐empirical correlated equations in chemical engineering science into CFD theory. Good agreements between the simulating results and experimental data for the effect of some parameters on reaction verified this model, for example heat exchange between reactor and atmosphere, the material property of reactor, the catalyst deactivated and gas mass flux and so on. By using this model as the designing tools, an optimized packed bed is proposed. Compared with the testing packed bed, the relevant reactor length can be reduced from 220 mm to 150 mm with the same hydrogen conversion and lower pressure drop. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-17T10:50:45.366024-05:
      DOI: 10.1002/aic.15245
       
  • Towards a mesoscale‐structure‐based kinetic theory for
           heterogeneous gas‐solid flow: Particle velocity distribution
           function
    • Authors: Junwu Wang; Bidan Zhao, Jinghai Li
      Abstract: Mesoscience has recently been proposed as a possible general concept for describing complex systems far from equilibrium, however, concrete formulations are needed, and particularly, a statistical mechanics foundation of mesoscience remains to be explored. To this end, the mathematical theory of stochastic geometry is combined with the EMMS principle under the concept of mesoscience to propose a statistical mechanics framework. An EMMS‐based particle velocity distribution function is then derived as an example to show how the proposed framework works, and more importantly, as a first key step towards a generalized kinetic theory for heterogeneous gas‐solid flow. It was shown that the resultant EMMS‐based distribution is bimodal, instead of the widely‐used Maxwellian distribution, but it reduces to the Maxwellian distribution when the gas‐solid system is homogeneous. The EMMS‐based distribution is finally validated by comparing its prediction of the variance of solid concentration fluctuation and granular temperature with experimental data. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-17T10:45:45.291833-05:
      DOI: 10.1002/aic.15244
       
  • Analysis of asymmetric morphology evolutions in iPP molded samples induced
           by uneven temperature field
    • Authors: Sara Liparoti; Andrea Sorrentino, Giuseppe Titomanlio
      Abstract: Mold surface temperature has a strong effect on the amount of molecular orientation and morphology developed in a non‐isothermal flowing polymer melt. In this work, a well‐characterized isotactic polypropylene was injected in a rectangular mold cavity asymmetrically conditioned by a thin electric heater specifically designed. The cavity surface was heated at temperatures ranging from 80°C to 160°C for different times (0.5, 8 and 18s) after the first contact with the polymer. Asymmetrical thermal conditions have a strong influence on the melt flow, by changing its distribution along the cavity thickness, and final part deformation. The morphology distribution of the molded samples was found strongly asymmetric with complex and peculiar features. Optical and Electron microscopy confirmed the complete reorganization of the crystalline structures along the sample thickness. X‐Rays analysis reveals that molecular orientation of the sample surface decreases with the mold temperature and the heating time. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-15T11:02:00.080435-05:
      DOI: 10.1002/aic.15241
       
  • Multi‐scale analysis of acoustic emission signals in
           
    • Authors: Lelu He; Yao Yang, Zhengliang Huang, Zuwei Liao, Jingdai Wang, Yongrong Yang
      Abstract: Acoustic emission (AE) technique in conjunction with multi‐scale processing method has been utilized to investigate the flow behavior of the dense‐phase pneumatic conveying system at high pressure. A clearly defined classification of micro‐scale, meso‐scale, and macro‐scale signals has been put forward with the aid of wavelet transform and V statistics analysis. The detailed signals d1‐d4, d5‐d7, d8‐d10 were recomposed into the micro‐scale, meso‐scale and macro‐scale signals, respectively, which represent micro‐scale particle‐wall interactions, meso‐scale interaction between gas phase and solid phase (such as bubbles, plugs, dunes), and macro‐scale flow‐induced pipe vibration. Further analysis shows that as the mass flow rate of pulverized coal increases, the energy fraction (energy of detailed signal divided by the energy of original signal) of micro‐scale signals decreases while that of meso‐scale signals increases, which indicates that particles are more likely to move as particle aggregates than individual particles when mass flow rate increases. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-15T10:56:39.442897-05:
      DOI: 10.1002/aic.15240
       
  • Solids volume fraction measurements on riser flow using a
           temporal‐histogram based DIA method
    • Authors: A.E. Carlos Varas; E.A.J.F. Peters, N.G. Deen, J.A.M. Kuipers
      Abstract: In this paper we introduce a temporal histogram‐based method for digital image analysis of pseudo‐2D fluidized bed risers. This method enables an accurate whole field measurement of the solids volume fraction in lab‐scale pseudo‐2D riser flows by successfully removing image imperfections and merely accounting for the particles' intensity. Moreover, the new correlation between normalized intensity and solids volume fraction that is proposed in this work enables a quantitative approach for solids concentration measurements by Digital Image Analysis (DIA) techniques. This technique can be easily adjusted with experimental settings and shows a great stability against adverse imaging conditions. The combination of this parameter‐free method with Particle Image Velocimetry (PIV) under riser flow conditions has been successfully applied, enabling the experimental acquisition of full field hydrodynamic data. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-15T10:56:13.434663-05:
      DOI: 10.1002/aic.15243
       
  • Model‐based analysis of chemical‐looping combustion
           experiments. Part II: Optimal design of CH4‐NiO reduction
           experiments
    • Authors: Lu Han; Zhiquan Zhou, George M. Bollas
      Abstract: There is significant controversy in the reduction kinetics of chemical‐looping combustion (CLC) between NiO and CH4. We propose an application of a model‐based framework to improve the quality of CLC experiments with respect to model discrimination and parameter estimation. First, optimal experiments are designed and executed to reject inadequate models and to determine a true model structure for the reaction kinetics of the CH4‐NiO system. Then, kinetics with statistical significance is estimated from experiments aimed at reducing parameter uncertainty. To maximize the observability of the NiO reduction reactions, fixed bed experiments should exhibit a peak separation of the concentration profiles, an initial high methane slip, and low overall CO2 selectivity. Several case studies are presented to check the adequacy of the recommended model and evaluate its predictive ability and extrapolation capabilities. The model resulting from this work is validated and suitable for application in process design and optimization. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-15T10:55:45.207341-05:
      DOI: 10.1002/aic.15242
       
  • Monte Carlo modeling of fluidized bed coating and layering processes
    • Abstract: A stochastic modeling approach based on a Monte Carlo method for fluidized bed layering and coating is presented. In this method, the process is described by droplet deposition on the particle surface, droplet drying and the formation of a solid layer due to drying. The model is able to provide information about the coating coverage (fraction of the particle surface covered with coating), the particle size distribution and the layer thickness distribution of single particles. Analytical solutions for simplified test cases are used to validate the model theoretically. The simulation results are compared with experimental data on particle size distributions and layer thickness distributions of single particles coated in a lab‐scale fluidized bed. Good agreement between the simulation results and the measured data is observed. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-14T18:17:06.212615-05:
      DOI: 10.1002/aic.15237
       
  • High‐performance polymer‐supported extractants with
           phosphonate ligands for scandium(III) separation
    • Authors: Hongmin Cui; Ji Chen, Hailian Li, Dan Zou, Yu Liu, Yuefeng Deng
      Abstract: As the market demand for scandium has grown, a great deal of interest has been generated in its recovery. To substantially simplify the process and provide a green alternative for scandium separation, novel polymer‐supported extractants containing di(2‐ethylhexyl) phosphonate and bis(2,4,4‐trimethylpentyl) phosphonate, [D201][DEHP] and [D201][C272] are proposed because they demonstrate improved adsorption capacity and selectivity toward scandium(III). Scandium(III) adsorption is significantly affected by the solution pH, with the maximum adsorption occurring at a pH of approximately 0.78. The batch adsorption data fit well with the Langmuir isotherm and pseudo‐second‐order kinetic models. A combination of the FTIR and XPS spectra suggest that the complexation of oxygen atoms in phosphate groups with scandium(III) is the predominant adsorption mechanism. Additionally, the two resins were used to recover scandium from leaching liquor of nickel laterite ore. [D201][DEHP] exhibits unusual selectivity for scandium and low competitive behavior with other metals, thus increasing its market potential. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-14T18:16:42.074411-05:
      DOI: 10.1002/aic.15236
       
  • Investigating the dynamics of cylindrical particles in a rotating drum
           using multiple radioactive particle tracking
    • Abstract: The behavior of granular flows inside rotating drums is an ongoing area of research. Only a few studies have investigated non‐spherical particles despite the fact that particle shape is known to have a significant impact on flow behavior. In addition, the experimental techniques limit the interpretation of the results of these studies. In this work, we compared the flow behavior of cylindrical and spherical particles using the multiple radioactive particle tracking (MRPT) technique to capture the positions and orientations of cylindrical particles simultaneously. We analyzed two important components of the transverse flow dynamics, that is, the boundary between the active and passive layers, and the velocity profile on the free surface. For the cylindrical particles, two general models are proposed to calculate the velocity profiles on the free surface and the effective particle sizes in the active and passive layers. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-14T18:16:13.270696-05:
      DOI: 10.1002/aic.15235
       
  • Development of gas‐phase smb technology for light olefin/paraffin
           separations
    • Abstract: The separation of ethylene from ethane is particularly complex due to their similar physical properties. Cryogenic distillation is the most common technology employed for this separation and is one of the most expensive operations in industry, being the driving force for the ongoing research to find a more cost‐effective alternative. In the present work, a gas‐phase SMB bench unit was employed to produce polymer‐grade ethylene from ethane/ethylene mixtures, using binderless 13X zeolite beads as adsorbent, and propane as desorbent. The achieved performance parameters demonstrated the high efficiency of the current technology, since ethylene was obtained with a purity of 99.8%, a recovery of 99.8%, and a productivity of 59.7 kgC2H4·h−1·madsorbent−3. Considering the encouraging results obtained it is fair to say that the gas‐phase SMB is a competitive and strong candidate as alternative to the conventional process, especially when combined with enhanced performance adsorbents, such as binderless zeolites. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-14T18:15:49.111374-05:
      DOI: 10.1002/aic.15238
       
  • High performance ZSM‐5 membranes on coarse macroporous
           α‐Al2O3 supports for dehydration of alcohols
    • Authors: Liangqing Li; Jianhua Yang, Jiajia Li, Jinqu Wang, Jinming Lu, Dehong Yin, Yan Zhang
      Abstract: High‐performance ZSM‐5 membranes with a low Si/Al ratio of 10.3 were prepared on cheap coarse macroporous α‐Al2O3 tubes by fluoride route without organic template. The effects of crystallization time and aluminum source on the growth, morphology and pervaporation (PV) performances of the as‐synthesized membranes were investigated. The feasibility of preparing ZSM‐5 membranes with different Si/Al ratio which was implemented by using different Al2(SO4)3·18H2O content in synthesis gel were discussed. It was found that the aluminum source had significant effect on the synthesis of membranes. The ZSM‐5 membranes prepared by using Al2(SO4)3·18H2O as an aluminum source from synthetic gel with composition of 1SiO2/0.05Al2O3/0.17Na2O/0.9NaF/45H2O showed high reproducibility and high PV performance with flux of 3.85 kg/(m2·h) and separation factor of larger than 10,000 in dehydration of 90 wt % i‐PrOH/H2O at 348 K. Moreover, the ZSM‐5 membranes exhibited high water perm‐selectivity performance for dehydration of 90 wt% n‐PrOH/H2O, n‐BtOH/H2O and i‐BtOH/H2O mixtures, respectively. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-14T10:49:32.018154-05:
      DOI: 10.1002/aic.15234
       
  • Mathematical Modeling of the Full Molecular Weight Distribution in ATRP
           techniques
    • Abstract: In this work the molecular weight distribution (MWD) of several ATRP techniques has been derived and solved using the Reduced Stiffness by Quasi Steady State Approximation (RSQSSA) methodology. The QSSA has been validated on the living radicals for normal, Simultaneous Reversible and Normal Initiation (SRNI) and Activators Regenerated by Electron Transfer (ARGET), and it is shown that the information lost due to its application is negligible. According to these results, RSQSSA shows the best performance in terms of wall‐clock time and required memory in comparison to implicit techniques and Predici. In the case of the ARGET technique, the model predictions show good agreement with experimental data. Finally, an analysis on the impact of the slow and fast activation of the initiator on the MWD using ARGET has been carried out, indicating that the optimal initiator to control the MWD should exhibit activation‐deactivation rates very similar to those of the polymeric equilibrium. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-14T10:49:01.350452-05:
      DOI: 10.1002/aic.15232
       
  • Heat Transfer Coefficient for Condensation of Steam on Freely Formed
           Falling Liquid Jets
    • Abstract: This paper presents the research results of direct contact condensation of steam on freely formed falling liquid jets. After the comparison of experimental data and open literature correlations it was concluded that published correlations does not provide accurate coverage of experimental data. A new correlation was established in the following form This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-14T10:42:12.781668-05:
      DOI: 10.1002/aic.15233
       
  • Length to Diameter Ratio of Extrudates in Catalyst Technology II. Bending
           Strength versus Impulsive Forces
    • Authors: Jean W. L. Beeckman; Natalie A. Fassbender, Theodore E. Datz
      Abstract: This paper describes the reduction of the length to diameter ratio of extrudates, by breakage upon collision with a surface. The approach links the rupture force of the extrudate by bending to the impulsive force the extrudate experiences due to collision. The bending or flexural strength of the extrudate is described by the Euler‐Bernoulli modulus of rupture. The impulsive force the extrudate experiences is described by Newton's second law. We apply the force balance at the asymptotic length to diameter ratio which is reached after many repeated impacts. This balance yields a dimensionless group as the ratio of the rupture force by bending to the impulsive force by collision. The analysis shows that the asymptotic length to diameter ratio is directly proportional to the square root of this group. This dimensionless group also allows one to define a severity of the collision via the impact velocity and the time of contact of the collision. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-09T17:44:10.79616-05:0
      DOI: 10.1002/aic.15231
       
  • Strain Mode of General Flow: Characterization and Implications for Flow
           Pattern Structures
    • Authors: Yasuya Nakayama; Tatsunori Masaki, Toshihisa Kajiwara
      Abstract: Understanding the mixing capability of mixing devices based on their geometric shape is an important issue both for predicting mixing processes and for designing new mixers. The flow patterns in mixers are directly connected with the modes of the local strain rate, which is generally a combination of elongational flow and planar shear flow. We develop a measure to characterize the modes of the strain rate for general flow occurring in mixers. The spatial distribution of the volumetric strain rate (or non‐planar strain rate) in connection with the flow pattern plays an essential role in understanding distributive mixing. With our measure, flows with different types of screw elements in a twin‐screw extruder are numerically analyzed. The difference in flow pattern structure between conveying screws and kneading disks is successfully characterized by the distribution of the volumetric strain rate. The results suggest that the distribution of the strain rate mode offers an essential and convenient way for characterization of the relation between flow pattern structure and the mixer geometry. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-09T17:39:51.885813-05:
      DOI: 10.1002/aic.15228
       
  • Dynamic Delayed Detached Eddy Simulation of a Multi‐Inlet Vortex
           Reactor
    • Authors: Zhenping Liu; Alberto Passalacqua, Michael G. Olsen, Rodney O. Fox, James C. Hill
      Abstract: The multi‐inlet vortex reactor (MIVR) is used for flash nanoprecipitation to manufacture functional nanoparticles. A validated computational fluid dynamics model is needed for the design, scale‐up, and optimization of the MIVR. Unfortunately, available Reynolds‐averaged Navier‐Stokes methods are unable to accurately model the highly swirling flow in the MIVR. Large‐eddy simulations (LES) are also problematic, as excessively fine grids are required to accurately model this flow. These dilemmas led to the application of the dynamic delayed detached eddy simulation (DDES) method to the MIVR. In the dynamic DDES model, the eddy viscosity has a form similar to the Smagorinsky sub‐grid viscosity in LES, which allows the implementation of a dynamic procedure to determine its model coefficient. Simulation results using the dynamic DDES model are found to match well with experimental data in terms of mean velocity and turbulence intensity, suggesting that the dynamic DDES model is a good option for modeling the turbulent swirling flow in the MIVR. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-09T17:37:44.797469-05:
      DOI: 10.1002/aic.15230
       
  • Numerical Studies of the Effects of Fines on Fluidization
    • Authors: Yile Gu; Ali Ozel, Sankaran Sundaresan
      Abstract: Euler‐Lagrange simulations of fluidized beds of Geldart Group A particles containing different levels of fines are performed in periodic domains with various domain‐averaged solid volume fractions. Bubble‐like voids readily form when no fines are added. Introducing fines does not reduce bubble sizes if van der Waals force between particles is not accounted for. In contrast, the addition of van der Waals force produces significant changes. With no fines, bubbles are found to be suppressed at sufficiently high solid volume fractions, corresponding to the expanded bed regime for Group A particles. With the addition of fines, bubbles can be suppressed at lower solid volume fractions. With more fines added, bubbles can be suppressed at even lower solid volume fractions. When bubbles are suppressed, the system is found to be in a stable solid‐like regime. In this regime, forces on each particle are balanced, and the particle velocity fluctuations are dampened. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-09T17:37:42.406049-05:
      DOI: 10.1002/aic.15229
       
  • New Insights into Sodium Alginate Fouling of Ceramic Hollow Fibre
           Membranes by NMR Imaging
    • Abstract: Ceramic hollow fibre membranes are investigated with respect to the fouling behavior. Constant pressure dead‐end filtration experiments have been performed using alginate as model substance for extracellular polymeric substances. In addition to the evaluation of the filtration data using conventional cake filtration model, nuclear magnetic resonance imaging was used to elucidate the influence of Ca2+ on the fouling layer structure for alginate filtration within ceramic hollow fibre membranes. In order to visualize the alginate layers inside the opaque ceramic hollow fibre membranes by means of MRI, specific contrast agents were applied. Supplementary to multi slice multi echo imaging, flow velocity measurements were performed to gain more insight into the hydrodynamics in the fouled membranes. MRI reveals the structure of the alginate layers with the finding that the addition of Ca2+ to the alginate feed solution promotes the formation of a dense alginate gel layer on the membrane's surface. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-06T06:54:01.805511-05:
      DOI: 10.1002/aic.15226
       
  • Mass Transfer Simulation on Pervaporation Dehydration of Ethanol through
           Hollow Fiber NaA Zeolite Membranes
    • Authors: Peng Ye; Yuting Zhang, Haifeng Wu, Xuehong Gu
      Abstract: A multi‐layer series‐resistance mass transfer model was developed to simulate mass transfer behaviors of water/ethanol mixture through hollow fiber NaA zeolite membranes. The mass transfer through zeolite layer was described by Maxwell‐Stefan mechanism based on adsorption and diffusion parameters obtained from molecular simulation. The mass transfer through asymmetric hollow fiber support was described by dusty gas model involving Knudsen diffusion and viscous flow. It was found that the sponge‐like layer of support besides of zeolite layer made an important contribution to overall membrane transfer resistance while the finger‐like layer had less effect. When permeate pressure shifted from 0.2 to 7.5 kPa, the mass transfer resistance contribution of sponge‐like layer varied from 27.1% to 17.8%. Effects of microstructure parameters of support on mass transfer through membrane were investigated extensively. Large pore size and thin thickness for sponge‐like layer of support were beneficial to improve water permeation flux. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-06T06:53:01.169837-05:
      DOI: 10.1002/aic.15227
       
  • Assessment of Inherently Safer Alternatives in Biogas Production and
           Upgrading
    • Authors: Giordano Emrys Scarponi; Daniele Guglielmi, Valeria Casson Moreno, Valerio Cozzani
      Abstract: Biogas is becoming an increasingly important resource of energy production from biomass, and a number of alternative technologies are proposed for its production and upgrading. However, in spite of the increasing number of accidents recorded, scarce attention was dedicated to date to the control and mitigation of biogas hazards. In the present study, inherent safety of biogas technologies was addressed. A method for the selection of inherently safer alternatives during early design stages was further developed and combined to a Monte Carlo sensitivity analysis, accounting for uncertainty of input parameters and addressing the robustness of the ranking provided. The method was applied to the assessment of several alternative reference process schemes for biogas production and upgrading. The results allowed the identification of critical safety issues and the ranking of inherently safer solutions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-06T06:51:58.982392-05:
      DOI: 10.1002/aic.15224
       
  • Model‐Based Analysis of Chemical‐Looping Combustion
           Experiments. Part I: Structural Identifiability of Kinetic Models for Nio
           Reduction
    • Authors: Lu Han; Zhiquan Zhou, George M. Bollas
      Abstract: To guide the design of chemical‐looping combustion (CLC) systems, the use of accurate models is crucial. The reduction kinetics between NiO and CH4 is uncertain, in regards to the most suitable kinetic mechanism and reaction network. A framework for structural identifiability analysis is developed and applied to evaluate the candidate kinetic models for the NiO‐CH4 reaction. The identifiability of kinetic parameters of different model structures is analyzed and compared. Models that lack structural identifiability of their kinetic parameters are rejected in the analysis. From a total of 160 possible candidate models, 4 kinetic models are found to be identifiable with respect to their kinetic parameters and distinguishable from different model structures. This structural identifiability analysis paves the way for model‐based design of experiments, which is the subject of Part II of this work. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-06T06:51:32.008907-05:
      DOI: 10.1002/aic.15225
       
  • .Wax Deposition Modeling of Oil/gas Stratified Smooth Pipe Flow
    • Authors: Jimiao Duan; Huishu Liu, Jinfa Guan, Weixing Hua, Guangwei Jiao, Jing Gong
      Abstract: Wax deposition modeling is complicated under oil/gas two‐phase pipe flow and therefore remains poorly understood. One‐dimensional empirical heat and mass transfer correlations are unreliably for deposition modeling in stratified flow, due to non‐uniform deposit across the pipe circumference. A mathematical model has been developed to predict the deposit thickness and the wax fraction of deposit in oil/gas stratified pipe flow using a unidirectional flow analysis of non‐isothermal hydrodynamics and heat/mass transfer. The predictions for wax deposition are found to compare satisfactorily with experimental data with three different oils for single phase and oil/gas stratified pipe flow. In particular, the reason that the deposit forming a crescent shape at the cross section of pipe observed in different experiments is revealed, based on the non‐uniform circumferential distributions of two most important parameters for the wax deposition, diffusivity at oil‐deposit interface, and the solubility gradient at the oil‐deposit interface at different time. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-06T06:51:04.119157-05:
      DOI: 10.1002/aic.15223
       
  • A Feedback Control Framework for Safe and Economically‐Optimal
           Operation of Nonlinear Processes
    • Authors: Fahad Albalawi; Anas Alanqar, Helen Durand, Panagiotis D. Christofides
      Abstract: Maintaining safe operation of chemical processes and meeting environmental constraints are issues of paramount importance in the area of process systems and control engineering, and are ideally achieved while maximizing economic profit. It has long been argued that process safety is fundamentally a process control problem, yet few research efforts have been directed towards integrating the rather disparate domains of process safety and process control. Economic model predictive control (EMPC) has attracted significant attention recently due to its ability to optimize process operation accounting directly for process economics considerations. However, there is very limited work on the problem of integrating safety considerations in EMPC to ensure simultaneous safe operation and maximization of process profit. Motivated by the above considerations, this work develops three EMPC schemes that adjust in real‐time the size of the safety sets in which the process state should reside in order to ensure safe process operation and feedback control of the process state while optimizing economics via time‐varying process operation. Recursive feasibility and closed‐loop stability are established for a sufficiently small EMPC sampling period. The proposed schemes, which effectively integrate feedback control, process economics and safety considerations, are demonstrated with a chemical process example. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-06T06:50:37.917598-05:
      DOI: 10.1002/aic.15222
       
  • On the Relation Between Flexibility Analysis and Robust Optimization for
           Linear Systems
    • Authors: Qi Zhang; Ricardo M. Lima, Ignacio E. Grossmann
      Abstract: Flexibility analysis and robust optimization are two approaches to solving optimization problems under uncertainty that share some fundamental concepts, such as the use of polyhedral uncertainty sets and the worst‐case approach to guarantee feasibility. The connection between these two approaches has not been sufficiently acknowledged and examined in the literature. In this context, the contributions of this work are fourfold: (1) a comparison between flexibility analysis and robust optimization from a historical perspective is presented; (2) for linear systems, new formulations for the three classical flexibility analysis problems—flexibility test, flexibility index, and design under uncertainty—based on duality theory and the affinely adjustable robust optimization (AARO) approach are proposed; (3) the AARO approach is shown to be generally more restrictive such that it may lead to overly conservative solutions; (4) numerical examples show the improved computational performance from the proposed formulations compared to the traditional flexibility analysis models. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-03T19:58:24.052907-05:
      DOI: 10.1002/aic.15221
       
  • Data‐Driven Mathematical Modeling and Global Optimization Framework
           for Entire Petrochemical Planning Operations
    • Authors: Jie Li; Fani Boukouvala, Xin Xiao, Christodoulos A. Floudas, Baoguo Zhao, Guangming Du, Xin Su, Hongwei Liu
      Abstract: In this work we develop a novel modeling and global optimization‐based planning formulation, which predicts product yields and properties for all of the production units within a highly integrated refinery‐petrochemical complex. Distillation is modeled using swing‐cut theory, while data‐based non‐linear models are developed for other processing units. The parameters of the postulated models are globally optimized based on a large data set of daily production. Property indices in blending units are linearly additive and they are calculated on a weight or volume basis. Binary variables are introduced to denote unit and operation modes selection. The planning model is a large‐scale non‐convex mixed integer nonlinear optimization model, which is solved to ε‐global optimality. Computational results for multiple case studies indicate that we achieve a significant profit increase (37%‐65%) using the proposed data‐driven global optimization framework. Finally, a user‐friendly interface is presented which enables automated updating of demand, specification and cost parameters. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-03T19:57:35.663147-05:
      DOI: 10.1002/aic.15220
       
  • An adhesive CFD‐DEM model for simulating nanoparticle agglomerate
           fluidization
    • Authors: Daoyin Liu; Berend G. M. van Wachem, Robert F. Mudde, Xiaoping Chen, J. Ruud van Ommen
      Abstract: Nanoparticles are fluidized as agglomerates with hierarchical fractal structures. In this study, we model nanoparticle fluidization by assuming the simple agglomerates as the discrete element in an adhesive CFD‐DEM model. The simple agglomerates, which are the building blocks of the larger complex agglomerates, are represented by cohesive and plastic particles. It is shown that both the particle contact model and drag force interaction in the conventional CFD‐DEM model need modification for properly simulating a fluidized bed of nanoparticle agglomerates. The model is tested for different cases, including the normal impact, angle of repose, and fluidization of nanoparticle agglomerates, represented by the particles with the equivalent material properties. It shows that increasing the particle adhesion increases the critical stick velocity, angle of repose, and leads from uniform fluidization to defluidization. The particle adhesion, bulk properties, and fluidization can be linked to each other by the current adhesive CFD‐DEM model. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-02T18:23:31.626318-05:
      DOI: 10.1002/aic.15219
       
  • Pd@C3N4 nanocatalyst for highly efficient hydrogen storage system based on
           potassium bicarbonate/formate
    • Authors: Xianzhao Shao; Jinming Xu, Yanqiang Huang, Xiong Su, Hongmin Duan, Xiaodong Wang, Tao Zhang
      Abstract: Formate/bicarbonate system has several desirable properties such as non‐corrosive and nonirritating nature, as well as facile handling, which make it an attractive candidate for a safe, reversible hydrogen storage material. Herein, we report Pd nanoparticles supported on mesoporous graphitic carbon nitride (mpg‐C3N4) for formate based reversible hydrogen storage. The as‐developed Pd/mpg‐C3N4 material was shown to be a superior catalyst for the hydrogenation of high concentrations of bicarbonate to formate under mild conditions. The effects of reaction temperature, H2 pressure, and bicarbonate concentration on the hydrogenation of bicarbonate to formate were investigated. The catalytic performance remained steady with high activity up to six hydrogenation cycles. The interaction between mpg‐C3N4 and Pd nanoparticles and the concerted effects of the nitrogen species located at mpg‐C3N4 and bicarbonate played a synergetic role in the enhancement of the performance of the catalyst for hydrogenation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-02T18:23:01.277817-05:
      DOI: 10.1002/aic.15218
       
  • Compressed isobutane as a solvent of heavy hydrocarbons
    • Abstract: This research provides solubility data required for environmental applications involving the extraction of heavy hydrocarbons with compressed gases. Dibenzothiophene (DBT), 2‐nitrophenyl disulfide (NPDS), and tetramethylthiuram disulfide (TTDS) have been selected as model compounds for this type of pollutants and isobutane as compressed gas. The solubilities obtained at 367‐413 K and 3.9‐7.5 MPa, expressed as solute mole fractions, were in the ranges 0.025‐0.106 for DBT, 1.2·10−4‐6.3·10−4 for NPDS, and between 2.7·10−4‐1.8·10−3 for TTDS. They were compared to other pollutants solubilities (anthracene and carbazole). From the comparison the following solubility order was established: DBT>anthracene>carbazole>TTDS>NPDS. Further, when comparing these isobutane solubilities to those in propane and CO2, they were found to be about one and two magnitude orders larger, respectively. Results obtained were explained considering solvent density, solute vapor pressure, and interactions between solutes and solvent. Peng‐Robinson equation was used to correlate the data and a good fitting attained. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-01T10:46:45.719894-05:
      DOI: 10.1002/aic.15216
       
  • Study on the Transient Interfacial Tension in a Microfluidic Droplet
           Formation Coupling Interphase Mass Transfer Process
    • Authors: Wenjie Lan; Shaowei Li, Che Wang, Xuqiang Guo, Guangsheng Luo
      Abstract: In two‐phase dispersion coupling interphase mass transfer process, the variation of interfacial tension is an important factor affecting the dispersion. In this study, we described a microfluidic method for the determination of the transient interfacial tension (TIFT). The method has the advantage of determining TIFT during the whole droplet formation process, rather than only at the rupture moment as reported in previous studies. The TIFTs of several systems were determined. In certain systems, it has been found that the droplet size decreased with the increase of the dispersed phase flow rate, which is obviously different from the constant interfacial tension system. It has also been found that TIFT was mainly affected by two‐phase flow rates, solute type and concentration, and droplet size. A semi‐empirical equation was finally established to predict TIFT. It has the potential to be used in a variety of industrial equipment with dispersion – mass transfer coupling process. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-01T10:45:57.605511-05:
      DOI: 10.1002/aic.15217
       
  • Distributional uncertainty analysis and robust optimization in spatially
           heterogeneous multiscale process systems
    • Abstract: Multiscale models have been developed to simulate the behaviour of spatially‐heterogeneous porous catalytic flow reactors, i.e. multiscale reactors whose concentrations are spatially‐dependent. While such a model provides an adequate representation of the catalytic reactor, model‐plant mismatch can significantly affect the reactor's performance in control and optimization applications. In this work, power series expansion (PSE) is applied to efficiently propagate parametric uncertainty throughout the spatial domain of a heterogeneous multiscale catalytic reactor model. The PSE‐based uncertainty analysis is used to evaluate and compare the effects of uncertainty in kinetic parameters on the chemical species concentrations throughout the length of the reactor. These analyses reveal that uncertainty in the kinetic parameters and in the catalyst pore radius have a substantial effect on the reactor performance. The application of the uncertainty quantification methodology is illustrated through a robust optimization formulation that aims to maximize productivity in the presence of uncertainty in the parameters. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-26T04:36:10.605915-05:
      DOI: 10.1002/aic.15215
       
  • Ethanol perm‐selective B‐ZSM‐5 zeolite membranes from
           dilute solutions
    • Authors: Lijun Chai; Jianhua Yang, Jinqu Wang, Jinming Lu, Dehong Yin, Yan Zhang
      Abstract: Boron‐substituted MFI (B‐ZSM‐5) zeolite membranes with high pervaporation (PV) performance were prepared onto seeded inexpensive macroporous α‐Al2O3 supports from dilute solution and explored for the separation of ethanol/water mixtures by PV. The effects of several parameters on microstructures and PV performance of the B‐ZSM‐5 membranes were examined systematically, including the seed size, synthesis temperature, crystallization time, B/Si ratio, H2O/SiO2 ratio and silica source. A continuous and compact B‐ZSM‐5 membrane was fabricated from solution containing 1 TEOS/0.2 TPAOH/0.06 H3BO3/600 H2O at 448 K for 24 h, showing a separation factor of 55 and a flux of 2.6 kg/m2·h along with high reproducibility for a 5 wt % ethanol/water mixture at 333 K. It was demonstrated that the incorporation of boron into MFI structure could increase the hydrophobicity of B‐ZSM‐5 membrane evidenced by the improved contact angle and amount of the adsorbed ethanol, and thus enhance the PV property for ethanol/water mixtures. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-25T03:53:17.815676-05:
      DOI: 10.1002/aic.15214
       
  • Process systems engineering perspective on the planning and development of
           oil fields
    • Authors: M Sadegh Tavallali; I A Karimi, D Baxendale
      PubDate: 2016-02-25T03:26:52.74302-05:0
      DOI: 10.1002/aic.15209
       
  • Perspectives on continuous manufacturing of powder‐based
           pharmaceutical processes
    • Authors: Marianthi Ierapetritou; Gintaras Reklaitis, Fernando Muzzio
      PubDate: 2016-02-25T03:25:46.892441-05:
      DOI: 10.1002/aic.15210
       
  • Evolution of functional polymer colloids for coatings and other
           applications
    • Authors: John Klier; James Bohling, Melinda Keefe
      PubDate: 2016-02-25T03:25:19.558113-05:
      DOI: 10.1002/aic.15211
       
  • Wetting Kinetics of Polymer Solutions and Force Based Contact Angles
    • Abstract: We have investigated here the effect of the shear thinning behavior and elasticity of polymer solutions on the dynamic contact angles. Under dynamic conditions, the contact angle of a liquid on a solid surface changes significantly with the substrate velocity from its equilibrium value. The dynamic contact angles for polyethylene oxide (PEO) solutions of two molecular weights 3x105 and 4 x106 have been measured using a polyethylene terephthalate (PET) plate. We have used the three‐ parameter Ellis model to fit the rheological data to obtain shear thinning power n, characteristic shear stress and the zero shear viscosity. The theory indicates that dynamic contact angles follow power law in this instance instead of showing Newtonian behavior with zero shear viscosity when the shear thinning effects are considered. The elastic effect becomes important at larger polymer concentrations that reduces the dependence on capillary number, that is, reduces n keeping with the experiments. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-24T18:20:31.924512-05:
      DOI: 10.1002/aic.15213
       
  • Experiment Design for Control‐Relevant Identification of Partially
           Known Stable Multivariable Systems
    • Authors: Shyam Panjwani; Michael Nikolaou
      Abstract: Design of experiments for identification of control‐relevant models is at the heart of robust controller design. In a number of prior publications, experiment designs have been developed that generate input/output data for efficient identification of models satisfying the integral controllability condition. The design of process inputs for such experiments is often, but not always, based on the concept of independent random rotated inputs, with appropriately proportioned amplitudes. However, prior publications do not account for models that may already be partially known before identification. In this work, we address this issue by developing a general experiment design framework for efficient identification of partially known models that must satisfy the integral controllability condition. This framework produces optimal designs by solving appropriately formulated optimization problems, based on a number of rigorous theoretical results. Numerical simulations illustrate the proposed approach and potential future extensions are suggested. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-24T18:02:52.055815-05:
      DOI: 10.1002/aic.15212
       
  • A cost‐effective model for the gasoline blend optimization problem
    • Abstract: Gasoline blending is a critical process with a significant impact on the total revenues of oil refineries. It consists of mixing several feedstocks coming from various upstream processes and small amounts of additives to make different blends with some specified quality properties. The major goal is to minimize operating costs by optimizing blend recipes, while meeting product demands on time and quality specifications. This work introduces a novel continuous‐time mixed‐integer linear programming (MILP) formulation based on floating time slots to simultaneously optimize blend recipes and the scheduling of blending and distribution operations. The model can handle non‐identical blenders, multipurpose product tanks, sequence‐dependent changeover costs, limited amounts of gasoline components, and multi‐period scenarios. Because it features an integrality gap close to zero, the proposed MILP approach is able to find optimal solutions at much lower computational cost than previous contributions when applied to large gasoline blend problems. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-22T03:46:47.67259-05:0
      DOI: 10.1002/aic.15208
       
  • Stability of an Inclined, Pneumatically‐Transported System of
           Particles
    • Authors: Kevin Mandich; Robert J. Cattolica
      Abstract: A linear stability analysis is performed on the base‐state solution describing a pneumatically‐transported system inclined at an angle θ. One of two modes was found to be dominant, depending on the tilting angle: a low‐shear mode whose voidage eigenmode remains nearly symmetric from 0°  θc, marked by significant asymmetry throughout the domain and a high level of shear inside the thin regions adjacent to the walls. The critical angle θc increases with the amount of momentum and energy lost to particle‐wall friction and collisions, respectively. The time‐evolution of the latter mode, superimposed onto the base‐state solution, reveals an alternating train of dense and dilute regions near the top of the domain, which agrees qualitatively with the development and propagation of bubbles in inclined systems observed in experiment. An analytic solution corresponding to a vertical system with a uniform base state was also derived to identify the instability mechanisms responsible for a class of non‐oscillatory transverse waves which exist in both vertical and tilted particle systems. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-18T10:37:12.048126-05:
      DOI: 10.1002/aic.15207
       
  • Global Optimization of Multicomponent Distillation Configurations: 2.
           Enumeration based Global Minimization Algorithm
    • Authors: Ulaganathan Nallasivam; Vishesh H. Shah, Anirudh A. Shenvi, Joshua Huff, Mohit Tawarmalani, Rakesh Agrawal
      Abstract: We present a general Global Minimization Algorithm (GMA) to identify basic or thermally coupled distillation configurations that require the least vapor duty under minimum reflux conditions for separating any ideal or near‐ideal multicomponent mixture into a desired number of product streams. In this algorithm, global optimality is guaranteed by modeling the system using Underwood equations and reformulating the resulting constraints to bilinear inequalities. The speed of convergence to the globally optimal solution is increased by using appropriate feasibility and optimality based variable‐range reduction techniques and by developing valid inequalities. The GMA can be coupled with already developed techniques that enumerate basic and thermally coupled distillation configurations, to provide for the first time, a global optimization based rank‐list of distillation configurations. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-10T22:34:03.440791-05:
      DOI: 10.1002/aic.15204
       
  • Kinetics of RAFT Emulsion Polymerization of Styrene Mediated by
           Oligo(acrylic acid‐b‐styrene) Trithiocarbonate
    • Authors: Kun Yan; Xiang Gao, Yingwu Luo
      Abstract: The kinetics of ab initio reversible addition‐fragmentation chain transfer (RAFT) emulsion polymerization of styrene using oligo(acrylic acid‐b‐styrene) trithiocarbonate as both polymerization mediator and surfactant were systematically investigated. The initiator concentration was set much lower than that in the conventional emulsion polymerization to significantly suppress the irreversible termination reaction. It was found that n¯ decreased rapidly but the nucleation efficiency of micelles increased with the decrease of the initiator concentrations due to the significant radical exit. The particle number (NP) did not follow the classic Smith‐Eward equation but was proportional to [I]−0.4[S]0.7. It was suggested that RAFT emulsion polymerization could be fast enough for commercial use even at extremely low initiator concentrations and low macro‐RAFT agent concentrations due to the higher particle nucleation efficiency at lower initiator concentration. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-06T11:14:17.319068-05:
      DOI: 10.1002/aic.15199
       
  • Process Design Methodology for Energy‐Efficient Processes Operating
           Below and Across Ambient Temperature
    • Authors: Danahe Marmolejo Correa; Truls Gundersen
      Abstract: This paper presents a targeting and design methodology that can be implemented for any process where pressure‐based exergy, also known as mechanical exergy, has an important contribution to the total exergy conversion and transfer. However, in this paper it is applied to processes that operate at sub‐ambient conditions, or processes where the ambient conditions are crossed. Exergy efficiencies, new Exergetic Composite Curves, Cascades, and Extended Grid Diagrams are tools that had to be implemented, improved or invented, in order to develop a methodology with considerable potential for energy‐efficient process design. The appropriate placement (correct integration) of compressors and expanders in heat exchanger networks is also analyzed to minimize the number of units. An example is used to demonstrate the methodology, where several simplifying assumptions are made to facilitate understanding and to explain the design method. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-06T10:48:55.291542-05:
      DOI: 10.1002/aic.15200
       
  • Chemical Conversion and Liquid‐Liquid Extraction of
           5‐Hydroxymethylfurfural from Fructose by Slug Flow Microreactor
    • Authors: Toshinori Shimanouchi; Satoko Fujioka, Yoshitaka Kataoka, Tatsuya Tanifuji, Koichi Terasaka, Yukitaka Kimura
      Abstract: A dehydration of fructose in the water/methyl isobuthyl ketone (MIBK) biphasic system can yield 5‐hydroxymethylfurfural (HMF) to be successfully extracted into the organic MIBK phase. The HMF production and yield in MIBK phase was discussed by using a simplified model taking into consideration of the slug flow. The extraction resistance of HMF across the interface between water and MIBK depended on the line velocity and the flow rate ratio. It was likely that the velocity field generated in the slug flow contributed to an increase in the mass transfer of HMF. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-06T10:48:29.223491-05:
      DOI: 10.1002/aic.15201
       
  • Multi‐fuel scaled‐down autothermal pure H2 generator: Design
           and proof of concept
    • Authors: Michael Patrascu; Moshe Sheintuch
      Abstract: This paper presents experimental results of an autothermal scaled‐down system for H2 production. Pure atmospheric pressure H2, separated in situ by Pd‐Ag membranes, is produced by steam reforming (SR) of methane, ethanol or glycerol. Oxidizing the SR effluents in a separate compartment supplies the heat. The oxidation feed is axially distributed to avoid hotspots. The 1.3L system, comprises 100cm2 of membrane area, and generates H2 flow rate equivalent to 0.15kW at an efficiency of ∼25%. This process leads to comparable performance when different fuels are used. A mathematical model, validated by the measurements, predicts that increasing the membrane area relative to the outer surface area will substantially increase the efficiency and power output. This design serves as proof of concept for on‐board pure H2 generators, with flexible fuel sources, and holds a great promise to reduce the need for special H2 transport and storage technologies for portable or stationary applications. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-02T17:42:02.020407-05:
      DOI: 10.1002/aic.15193
       
  • Multi‐period planning, design and strategic models for
           long‐term, quality‐sensitive shale gas development
    • Authors: Markus G. Drouven; Ignacio E. Grossmann
      Abstract: In this work we address the long‐term, quality‐sensitive shale gas development problem. This problem involves planning, design and strategic decisions such as where, when and how many shale gas wells to drill, where to lay out gathering pipelines, as well as which delivery agreements to arrange. Our objective is to use computational models to identify the most profitable shale gas development strategies. For this purpose we propose a large‐scale, nonconvex, mixed‐integer nonlinear programming (MINLP) model. We rely on generalized disjunctive programming (GDP) to systematically derive the building blocks of this model. Based on a tailor‐designed solution strategy we identify near‐global solutions to the resulting large‐scale problems. Finally, we apply the proposed modeling framework to two case studies based on real data to quantify the value of optimization models for shale gas development. Our results suggest that the proposed models can increase upstream operators' profitability by several million U.S. dollars. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-23T02:43:13.60821-05:0
      DOI: 10.1002/aic.15174
       
  • Integrated gasoline blending and order delivery operations: Part I.
           Short‐term scheduling and global optimization for single and
           multi‐period operations
    • Authors: Jie Li; Xin Xiao, Christodoulos A. Floudas
      Abstract: Gasoline is one of the most valuable products in an oil refinery and can account for as much as 60‐70% of total profit. Optimal integrated scheduling of gasoline blending and order delivery operations can significantly increase profit by avoiding ship demurrage, improving customer satisfaction, minimizing quality give‐aways, reducing costly transitions and slop generation, exploiting low‐quality cuts, and reducing inventory costs. In this paper, we first introduce a new unit‐specific event‐based continuous‐time formulation for the integrated treatment of recipes, blending, and scheduling of gasoline blending and order delivery operations. Many operational features are included such as non‐identical parallel blenders, constant blending rate, minimum blend length and amount, blender transition times, multi‐purpose product tanks, changeovers, and piecewise constant profiles for blend component qualities and feed rates. To address the non‐convexities arising from forcing constant blending rates during a run, we propose a hybrid global optimization approach incorporating a schedule adjustment procedure, iteratively via a MIP and NLP scheme, and a rigorous deterministic global optimization approach. The computational results demonstrate that our proposed formulation does improve the MILP relaxation of Li and Karimi, Ind. Eng. Chem. Res., 2011, 50, 9156‐9174. All examples are solved to be 1%‐ global optimality with modest computational effort. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-19T18:44:20.893338-05:
      DOI: 10.1002/aic.15168
       
  • Issue information ‐ table of contents
    • Pages: 1845 - 1845
      PubDate: 2016-04-20T08:52:01.058446-05:
      DOI: 10.1002/aic.14990
       
  • Extended HPM–DEM coupled simulation of drainage of square particles
           in a 2D hopper flow
    • Authors: Nan Gui; Xingtuan Yang, Shengyao Jiang, Jiyuan Tu, Jianren Fan
      Pages: 1863 - 1876
      Abstract: An extended hard particle method–discrete element method coupled model (EHPM–DEM) is proposed to simulate the drainage of square particle in 2D hoppers. The EHPM extends the hard sphere model to adapt for non‐spherical shapes. A vertex‐based extension of DEM is developed to solve collisions of square particles. A new coupled method is proposed, using the EHPM to simulate binary collisions and DEM to simulate multiple contacts. The collision between two triangles and the drainage of square particles in hoppers were simulated and compared to theoretical analysis and experiments, respectively, for validation. Moreover, the advantages of EHPM over DEM and the EHPM–DEM coupled solution over the pure soft DEM solution in computational efficiency have been demonstrated. In addition, the effects of restitution coefficient, friction coefficient, and the filled height on the discharge rates are analyzed, and a uniform discharge feature is discovered, which is especially useful for scaling studies. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1863–1876, 2016
      PubDate: 2016-02-13T13:41:20.270944-05:
      DOI: 10.1002/aic.15191
       
  • A model to predict liquid bridge formation between wet particles based on
           direct numerical simulations
    • Authors: Mingqiu Wu; Stefan Radl, Johannes G. Khinast
      Pages: 1877 - 1897
      Abstract: We study dynamic liquid bridge formation, which is relevant for wet granular flows involving highly viscous liquids and short collisions. Specifically, the drainage process of liquid adhering to two identical, non‐porous wet particles with different initial film heights is simulated using Direct Numerical Simulations (DNS). We extract the position of the interface, and define the liquid bridge and its volume by detecting a characteristic neck position. This allows us building a dynamic model for predicting bridge volume, and the liquid remaining on the particle surface. Our model is based on two dimensionless mobility parameters, as well as a dimensionless time scale to describe the filling process. In the present work model parameters were calibrated with DNS data. We find that the proposed model structure is sufficient to collapse all our simulation data, indicating that our model is general enough to describe liquid bridge formation between equally sized particles. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1877–1897, 2016
      PubDate: 2016-02-16T11:33:51.399657-05:
      DOI: 10.1002/aic.15184
       
  • CFD–DEM investigation into the scaling up of spout‐fluid beds
           via two interconnected chambers
    • Authors: Shiliang Yang; Andy Cahyadi, Yuhao Sun, Jingwei Wang, Jia Wei Chew
      Pages: 1898 - 1916
      Abstract: The hydrodynamics and chamber interaction in a three‐dimensional spout‐fluid bed with two interconnected chambers are investigated via computational fluid dynamics coupled with discrete element method (CFD–DEM), because multiple interconnected chambers are key to scaling up spout‐fluid beds. The overall solid motion, spouting evolution, and spout‐annulus interface is studied, followed by time‐averaged hydrodynamics, particle‐scale information, spout‐annulus interaction, and inter‐chamber interaction. The results show that inter‐chamber interactions lead to unique characteristics distinct from that for a single‐chamber system, including (1) asymmetry of the hydrodynamics within each chamber, (2) alternative spouting behavior in the two chambers, (3) smaller pressure drop in terms of magnitude and fluctuations, (4) two peaks in the solid residence time (SRT) frequency histogram of the annulus, (5) average SRT in the spout is twice that in a single‐chamber, and (6) larger solid dispersion in all three directions. The results provide meaningful understanding for the scale‐up of spout‐fluid beds. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1898–1916, 2016
      PubDate: 2016-02-16T11:37:19.133991-05:
      DOI: 10.1002/aic.15188
       
  • Particle‐resolved direct numerical simulation of gas–solid
           dynamics in experimental fluidized beds
    • Authors: Kun Luo; Junhua Tan, Zeli Wang, Jianren Fan
      Pages: 1917 - 1932
      Abstract: Particle‐resolved direct numerical simulations (PR‐DNS) of a simplified experimental shallow fluidized bed and a laboratory bubbling fluidized bed are performed by using immersed boundary method coupled with a soft‐sphere model. Detailed information on gas flow and individual particles’ motion are obtained and analyzed to study the gas–solid dynamics. For the shallow bed, the successful predictions of particle coherent oscillation and bed expansion and contraction indicate all scales of motion in the flow are well captured by the PD‐DNS. For the bubbling bed, the PR‐DNS predicted time averaged particle velocities show a better agreement with experimental measurements than those of the computational fluid dynamics coupled with discrete element models (CFD‐DEM), which further validates the predictive capability of the developed PR‐DNS. Analysis of the PR‐DNS drag force shows that the prevailing CFD‐DEM drag correlations underestimate the particle drag force in fluidized beds. The particle mobility effect on drag correlation needs further investigation. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1917–1932, 2016
      PubDate: 2016-02-17T09:47:07.786146-05:
      DOI: 10.1002/aic.15186
       
  • Coupled fluid‐particle modeling of a slot die coating system
    • Authors: V. Akbarzadeh; A. N. Hrymak
      Pages: 1933 - 1939
      Abstract: This work seeks to develop a fundamental understanding of particle motion in the slot die coating process through studying the interaction of forces between particles, with the die walls and the fluid phase. Coupled computational fluid dynamics and the discrete element method is employed for evaluating the motion of individual suspended particles near moving surfaces in a complex three‐dimensional flow field, motivated by the flow of particle laden fluid in a slot die coating system, including the presence of free surfaces. Overall, the particles follow the flow streamlines and their final position in the coating depends on the initial entry region of the particles. Particles experiencing adhesion with each other agglomerate in the low velocity regions of the coating gap, and have long residence times near the edge of the die at the end of the feed slot in the coating gap. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1933–1939, 2016
      PubDate: 2016-02-17T12:32:59.321607-05:
      DOI: 10.1002/aic.15187
       
  • Minimum fluidization velocity in gas‐liquid‐solid
           minifluidized beds
    • Authors: Yanjun Li; Mingyan Liu, Xiangnan Li
      Pages: 1940 - 1957
      Abstract: The initial fluidization characteristics of gas‐liquid‐solid minifluidized beds (MFBs) were experimentally investigated based on the analyses of bed pressure drop and visual observations. The results show that ULmf in 3–5 mm MFBs can not be determined due to the extensive pressure drop fluctuations resulting from complex bubble behavior. For 8–10 mm MFBs, ULmf can be confirmed from both datum analyses of pressure drop and Hurst exponent at low superficial gas velocity. But at high superficial gas velocity, ULmf was not obtained because the turning point at which the flow regime changes from the packed bed to the fluidized bed disappeared, and the bed was in a half fluidization state. Complex bubble growth behavior resulting from the effect of properties of gas‐liquid mixture and bed walls plays an important role in the fluidization of solid particles and leads to the reduction of ULmf. An empirical correlation was suggested to predict ULmf in MFBs. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1940–1957, 2016
      PubDate: 2016-02-17T12:38:11.032112-05:
      DOI: 10.1002/aic.15196
       
  • Direct numerical simulations of dynamic gas‐solid suspensions
    • Authors: Yali Tang; E. A. J. F. Peters, J. A. M. Kuipers
      Pages: 1958 - 1969
      Abstract: Direct numerical simulation results for gas flow through dynamic suspensions of spherical particles is reported. The simulations are performed using an immersed boundary method, with careful correction for the grid resolution effect. The flow systems we have studied vary with mean flow Reynolds number, solids volume fraction, as well as particle/gas density ratio. On the basis of the simulation results, the effect of particle mobility on the gas‐solid drag force is analyzed and introduced into the existing drag correlation that was derived from simulations of stationary particles. This mobility effect is characterized by the granular temperature, which is a result of the particle velocity fluctuation. The modified drag correlation is considered so‐far the most accurate expression for the interphase momentum exchange in computational fluid dynamics models, in which the gas‐solid interactions are not directly resolved. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1958–1969, 2016
      PubDate: 2016-02-18T11:30:26.914525-05:
      DOI: 10.1002/aic.15197
       
  • Experimental and numerical study on a bubbling fluidized bed with wet
           particles
    • Authors: Tianyu Wang; Yurong He, Tianqi Tang, Wengen Peng
      Pages: 1970 - 1985
      Abstract: As liquid bridge between particles acts an important role in the particle system, it is of considerable significance to analyze the flow hydrodynamics of wet particles in fluidized beds, which will improve the reactor design and process optimization. Thus, experimental and numerical investigations on wet particles in a bubbling fluidized bed are conducted in current work. On experimental side, particle image velocimetry (PIV) technology is employed with a designed bubbling fluidized bed. The silicone oil is used in this work because it is nonvolatile and transparent. On numerical side, a modified discrete element method (DEM) numerical method is developed by compositing an additional liquid‐bridge module into the traditional soft‐sphere interaction model. Most of the physical parameters are chosen to correspond to the experimental settings. Good agreements of particle velocity are found between the DEM simulation and PIV measurement. The performance of different liquid contents and superficial gas velocities are examined. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1970–1985, 2016
      PubDate: 2016-02-20T18:52:58.668821-05:
      DOI: 10.1002/aic.15195
       
  • Functional unfold principal component regression methodology for analysis
           of industrial batch process data
    • Pages: 1986 - 1994
      Abstract: This work proposes a methodology utilizing functional unfold principal component regression (FUPCR), for application to industrial batch process data as a process modeling and optimization tool. The methodology is applied to an industrial fermentation dataset, containing 30 batches of a production process operating at Novozymes A/S. Following the FUPCR methodology, the final product concentration could be predicted with an average prediction error of 7.4%. Multiple iterations of preprocessing were applied by implementing the methodology to identify the best data handling methods for the model. It is shown that application of functional data analysis and the choice of variance scaling method have the greatest impact on the prediction accuracy. Considering the vast amount of batch process data continuously generated in industry, this methodology can potentially contribute as a tool to identify desirable process operating conditions from complex industrial datasets. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1986–1994, 2016
      PubDate: 2016-02-02T02:17:37.416418-05:
      DOI: 10.1002/aic.15172
       
  • Subsystem decomposition and configuration for distributed state estimation
    • Authors: Xunyuan Yin; Kevin Arulmaran, Jinfeng Liu, Jing Zeng
      Pages: 1995 - 2003
      Abstract: Distributed state estimation plays a very important role in process control. Improper subsystem decomposition for distributed state estimation may increase the computational burdens, degrade the estimation performance, or even deteriorate the observability of the entire system. The subsystem decomposition problem for distributed state estimation of nonlinear systems is investigated. A systematic procedure for subsystem decomposition for distributed state estimation is proposed. Key steps in the procedure include observability test of the entire system, observable states identification for each output measurement, relative degree analysis and sensitivity analysis between measured outputs and states. Considerations with respect to time‐scale multiplicity and direct graph are discussed. A few examples are used to illustrate the applicability of the methods used in different steps. The effectiveness of the entire distributed state estimation configuration procedure is also demonstrated via an application to a chemical process example used in coal handling and preparation plants. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1995–2003, 2016
      PubDate: 2016-02-11T04:09:51.339788-05:
      DOI: 10.1002/aic.15170
       
  • Actuator stiction compensation via model predictive control for nonlinear
           processes
    • Authors: Helen Durand; Panagiotis D. Christofides
      Pages: 2004 - 2023
      Abstract: The problem of valve stiction is addressed, which is a nonlinear friction phenomenon that causes poor performance of control loops in the process industries. A model predictive control (MPC) stiction compensation formulation is developed including detailed dynamics for a sticky valve and additional constraints on the input rate of change and actuation magnitude to reduce control loop performance degradation and to prevent the MPC from requesting physically unrealistic control actions due to stiction. Although developed with a focus on stiction, the MPC‐based compensation method presented is general and has potential to compensate for other nonlinear valve dynamics which have some similarities to those caused by stiction. Feasibility and closed‐loop stability of the proposed MPC formulation are proven for a sufficiently small sampling period when Lyapunov‐based constraints are incorporated. Using a chemical process example with an economic model predictive controller (EMPC), the selection of appropriate constraints for the proposed method is demonstrated. The example verified the incorporation of the stiction dynamics and actuation magnitude constraints in the EMPC causes it to select set‐points that the valve output can reach and causes the operating constraints to be met. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2004–2023, 2016
      PubDate: 2016-02-13T13:07:50.147233-05:
      DOI: 10.1002/aic.15171
       
  • Model‐predictive safety system for proactive detection of operation
           hazards
    • Authors: Taha Mohseni Ahooyi; Masoud Soroush, Jeffrey E. Arbogast, Warren D. Seider, Ulku G. Oktem
      Pages: 2024 - 2042
      Abstract: A method of designing model‐predictive safety systems that can detect operation hazards proactively is presented. Such a proactive safety system has two major components: a set of operability constraints and a robust state estimator. The safety system triggers alarm(s) in real time when the process is unable to satisfy an operability constraint over a receding time‐horizon into the future. In other words, the system uses a process model to project the process operability status and to generate alarm signals indicating the presence of a present or future operation hazard. Unlike typical existing safety systems, it systematically accounts for nonlinearities and interactions among process variables to generate alarm signals; it provides alarm signals tied to unmeasurable, but detectable, state variables; and it generates alarm signals before an actual operation hazard occurs. The application and performance of the method are shown using a polymerization reactor example. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2024–2042, 2016
      PubDate: 2016-02-16T11:30:30.018362-05:
      DOI: 10.1002/aic.15152
       
  • The selectivity for sulfur removal from oils: An insight from conceptual
           density functional theory
    • Authors: Hongping Li; Wenshuai Zhu, Siwen Zhu, Jiexiang Xia, Yonghui Chang, Wei Jiang, Ming Zhang, Yuwei Zhou, Huaming Li
      Pages: 2087 - 2100
      Abstract: The selectivity for sulfur removal from oils is an important topic. In this work, the selectivity for different sulfur removal methods has been studied by conceptual density functional theory (CDFT) at the B3LYP/6‐311++G(3df,2p) level of theory. In principle, the selectivity is directly related to the mechanisms of sulfur removal. It cannot be precisely elucidated until the mechanisms are totally known. However, current work shows that relationships can be constructed between CDFT and the selectivity. That is, for hydrodesulfurization, good descriptors will be ionization energy, hardness, and bond lengths of SC; for adsorptive desulfurization, the hardness is a good descriptor; for oxidative desulfurization, good descriptors are electron density and Fukui function. And for extractive desulfurization (nonmetal‐based ionic liquids), electron affinity and electrophilicity may be good descriptors. In addition, structures and frontier orbitals of various sulfides have also been discussed. It is hoped that these relationships between CDFT and selectivity can give useful information to develop highly efficient sulfur removal methods for specific sulfides, like 4,6‐dimethyldibenzothiophene, and 4‐methyldibenzothiophene. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2087–2100, 2016
      PubDate: 2016-01-29T15:46:24.36938-05:0
      DOI: 10.1002/aic.15161
       
  • High‐temperature pyrolysis and CO2 gasification of Victorian brown
           coal and Rhenish lignite in an entrained flow reactor
    • Pages: 2101 - 2111
      Abstract: The low rank coals from Victoria, Australia, and Rhineland, Germany are of interest for use in entrained flow gasification applications. Therefore, a high temperature, electrically heated, entrained flow apparatus has been designed to address the shortage of fundamental data. A Victorian brown coal and a Rhenish lignite were subjected to rapid, entrained flow pyrolysis between 1100 and 1400°C to generate high surface area chars, which were subsequently gasified at the same temperatures under CO2 in N2 between 10 and 80 vol %. The Victorian coal was more reactive than the Rhenish coal, and peak char reactivity was observed at 1200°C. Char conversion and syngas yield increased with increasing temperature and plateaued at high CO2 concentration. Ammonia and tar species were negligible and HCN and H2S were present in parts per million (volume) concentrations in the cooled, filtered syngas. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2101–2111, 2016
      PubDate: 2016-02-18T11:30:53.218337-05:
      DOI: 10.1002/aic.15198
       
  • Drying of a system of multiple solvents: Modeling by the reaction
           engineering approach
    • Authors: Aditya Putranto; Xiao Dong Chen
      Pages: 2144 - 2153
      Abstract: Drying is a very important industrial operation in society. In drying, solute may dissolve in an aqueous solvent, a nonaqueous solvent or a mixture of solvents. Many mathematical models have been published previously to model drying of solute in water. The reaction engineering approach (REA) is known to be an easy‐to‐use approach. It can describe well many drying cases of water removal. Currently, no simple lumped model has been attempted to describe drying of porous materials containing a mixture of solvents. In this study, for the first time, REA is constructively implemented to model drying in a mixture of one aqueous and one nonaqueous solvent. The REA is applied here to model the drying of polyvinyl alcohol/methanol/water under constant and time‐varying environmental conditions. Similar to the relative activation energy of water, that of methanol is generated through one accurate drying run. For modeling the time‐varying drying, the relative activation energies are the same as those for modeling convective drying under constant ambient conditions but combined with the equilibrium activation energies at the corresponding humidity, methanol concentration, and temperature for each drying period. The REA is accurate to model drying of a solute in nonaqueous solvent as well as in a mixture of noninteracting solvents. In the future, spatially distributed REA for nonaqueous or mixtures of both aqueous and nonaqueous solvent will be explored for fundamental understanding and for practical application. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2144–2153, 2016
      PubDate: 2016-02-10T12:22:17.3744-05:00
      DOI: 10.1002/aic.15176
       
  • Electrically accelerated removal of organic pollutants by a
           three‐dimensional graphene aerogel
    • Pages: 2154 - 2162
      Abstract: Fast and effective methods for the removal of pollutants are crucial for the development of new sustainable water treatment technologies. In this work, we have reported the electrically accelerated removal of some typical organic pollutants by a three‐dimensional graphene aerogel (3DG). The porous 3DG was fabricated by chemical reduction of graphene oxide. The morphology and structure of 3DG were characterized by microscopic and spectroscopic approaches. The experiments indicated that 3DG‐based electrosorption could accelerate the removal of positively and negatively charged pollutants, such as Acid Red 88, Orange II, and Methylene Blue, as well as enhance the maximum adsorption capacity toward these contaminants. The interaction mechanisms between these organic pollutants and 3DG surface were further elucidated by Dispersion corrected Density Functional Theory (DFT‐D) calculations. This 3DG‐based system offers a potentially effective method for the rapid removal of organic pollutants and provides a new sustainable approach for water and wastewater treatment. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2154–2162, 2016
      PubDate: 2016-02-13T13:40:44.67174-05:0
      DOI: 10.1002/aic.15185
       
  • Reversed micelle synergistic extraction from phosphonium ionic liquid
           extractants in diluent for rare earth
    • Authors: Yamin Dong; Xiaoqi Sun, Yanliang Wang, Yujun Chai
      Pages: 2163 - 2169
      Abstract: The first synergistic extraction between quaternary phosphonium type ionic liquid extractants in toluene for rare earth was reported in this article. There were two different ion‐association mechanisms in the synergistic extraction system. The formed reversed micelles contributed to increase extractability of the synergistic extraction system to a considerable extent. On the one hand, million tons of saponification wastewater from acidic extractants may be avoided by developing the extraction system using bifunctional ionic liquid extractants. On the other hand, the novel synergistic extraction offers an effective strategy to increase the extractabilities of industrial extractants. This article reveals sustainable and efficient potentials for industrial rare earth separation. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2163–2169, 2016
      PubDate: 2016-02-18T10:37:58.146379-05:
      DOI: 10.1002/aic.15179
       
  • Partial Oxidation of Methane to Syngas in a Packed Bed Catalyst Membrane
           Reactor
    • Pages: 2170 - 2176
      Abstract: The planar membrane reactor configuration was explored for partial oxidation of methane (POM) to syngas. A supported membrane composed of yttria‐stabilized zirconia and La0.8Sr0.2Cr0.5Fe0.5O3‐δ was sealed to a stainless holder, and a Ni/Al2O3 catalyst bed was placed under the membrane plane with a small slit between them. This reactor configuration would facilitate the POM reaction via oxidation‐reforming mechanism: the oxidation reaction occurring at the membrane surface and the reforming reaction taking place in the catalyst bed. At 800°C and a methane feed rate of 32 mL min−1, the reactor attained methane throughput conversion over 90%, CO and H2 selectivity both over 95%, and an equivalent oxygen permeation rate 1.4 mL cm−2 min−1. The membrane and catalyst remained intact after the POM testing. The planar membrane reactor configuration explored in this study may lead to the development of a compact reactor for syngas production. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2170–2176, 2016
      PubDate: 2016-02-25T13:11:38.232069-05:
      DOI: 10.1002/aic.15202
       
  • Study on rheology and thermal stability of mixed (nonionic–anionic)
           surfactant based fracturing fluids
    • Authors: Atrayee Baruah; Akhilendra K. Pathak, Keka Ojha
      Pages: 2177 - 2187
      Abstract: Mixed surfactant systems have gained significant importance in the development of fracturing fluid due to polymorphism of self‐assembly structures that have combined properties of the surfactants in the mixture. In this article, a comparative study on the phase behavior and viscoelastic properties of mixed surfactant based fluids, prepared from Tween 80+NaOA/2‐ethyl hexanol/clove oil/water and Tween 20+NaOA/2‐ethyl hexanol/clove oil/water quaternary system is investigated in details. The viscoelastic surfactant (VES) based fluids prepared from the former system offered superior rheological properties than the latter system. The addition of 0.1% NaOH and 500 ppm ZnO nano‐particles in the VES fluids presented enhanced viscoelastic properties as concluded by static and dynamic rheological tests. Miscibility test indicated the miscibility of the VES fluids with water, unlike in the presence of diesel oil and satisfactory proppant suspension capabilities were exhibited by the developed fluids. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2177–2187, 2016
      PubDate: 2016-02-05T00:05:20.690665-05:
      DOI: 10.1002/aic.15175
       
  • Characterization of extensional rheological filament stretching with a
           dual‐mode Giesekus model
    • Authors: Bart Hallmark; D. Ian Wilson, Nicolas Pistre
      Pages: 2188 - 2199
      Abstract: A new, simple, formulation that describes capillary thinning as predicted by a two‐mode Giesekus model is derived, and its application in analyzing data from extensional rheometry (capillary thinning) experiments is discussed. An algorithm is presented that can be used to fit the expressions obtained from the Giesekus model to extensional rheometry data. Examples of data fitting are given for an idealized data set, for measurements obtained for aqueous solutions of 6 wt % 900,000 molecular weight polyethylene oxide, and for biological fluids obtained from pitchers of Nepenthes Rafflesiana. Good fits to the data were obtained, with coefficients of determination in excess of 0.98. For each data set, it was possible to calculate values of extensional viscosity and relaxation time for each of the two modes, allowing quantitative comparison of different fluids or of the same fluid as it ages. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2188–2199, 2016
      PubDate: 2016-02-24T09:28:32.641592-05:
      DOI: 10.1002/aic.15182
       
  • An elastic analog model for controlling the impingement point position in
           confined impinging jets
    • Pages: 2200 - 2212
      Abstract: Confined impinging jets (CIJs) are highly efficient mixers. The scales of mixing in CIJs are controlled by the opposed jets interaction. A mechanistic model is described here, which accurately predicts the impinging position of the opposed jets for a large range of flow rate ratios. The impinging point position is shown to impact the dynamic properties of the flow and the achieved mixing quality. The opposed jets kinetic energy ratio is shown to have a critical impact on mixing, similar to the Reynolds number. A mixing chamber design relation is proposed and verified for the opposed injectors diameters ratio, d1/d2, which enables to operate CIJs under optimum mixing conditions for large ranges of flow rate ratios, viscosity and density ratios between the opposed streams. Optimum d1/d2 values have asymptotes for large and small Reynolds number depending on the process stoichiometry, viscosity, and density ratios of the opposed jet streams. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2200–2212, 2016
      PubDate: 2016-02-10T12:47:12.288537-05:
      DOI: 10.1002/aic.15169
       
  • Characterization of the liquid film flow in a centrifugal separator
    • Authors: H. E. M. Ninahuanca; H. Stel, R. E. M. Morales, C. Ofuchi, M. J. da Silva, F. Neves
      Pages: 2213 - 2226
      Abstract: This work presents the characterization of the flow in a centrifugal separator. The study is focused on the behavior of the liquid phase in this kind of equipment, so that only single‐phase liquid flow at the inlet of the separator is considered. The parameters investigated are the film thickness, the flow velocity components, the flow streamlines angles and the liquid level height above the inlet. These quantities were assessed for different flow rates using numerical simulations and experimental measurements. Results show that an increase on the inlet flow rate causes an increase on the liquid film thickness and the liquid level height. Also, the centrifugal movement is intensified when the flow rate increases. The numerical results proved to describe the overall flow behavior satisfactorily when compared to the experiments. From the outcomes of this study, information can be extracted to understand the separation process in this type of separator. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2213–2226, 2016
      PubDate: 2016-02-10T12:46:44.214019-05:
      DOI: 10.1002/aic.15181
       
  • Temperature gradients drive radial fluid flow in petri dishes and
           multiwell plates
    • Authors: Stephen M. Lindsay; John Yin
      Pages: 2227 - 2233
      Abstract: Liquid in a Petri dish spontaneously circulates in a radial pattern, even when the dish is at rest. These fluid flows have been observed and utilized for biological research, but their origins have not been well‐studied. Here, particle‐tracking to measure velocities of radial fluid flows, which are shown to be linked to evaporation, is used. Infrared thermal imaging was used to identify thermal gradients at the air‐liquid interface and at the bottom of the dish. Two‐color ratiometric fluorescence confocal imaging was used to measure thermal gradients in the vertical direction within the fluid. A finite‐element model of the fluid, incorporating the measured temperature profiles, shows that buoyancy forces are sufficient to produce flows consistent with the measured particle velocity results. Such flows may arise in other dish or plate formats, and may impact biological research in positive or negative ways. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2227–2233, 2016
      PubDate: 2016-02-17T12:19:42.896989-05:
      DOI: 10.1002/aic.15194
       
 
 
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