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  Subjects -> ENGINEERING (Total: 1964 journals)
    - CHEMICAL ENGINEERING (151 journals)
    - CIVIL ENGINEERING (148 journals)
    - ELECTRICAL ENGINEERING (81 journals)
    - ENGINEERING (1120 journals)
    - ENGINEERING MECHANICS AND MATERIALS (293 journals)
    - HYDRAULIC ENGINEERING (45 journals)
    - INDUSTRIAL ENGINEERING (52 journals)
    - MECHANICAL ENGINEERING (74 journals)

ENGINEERING (1120 journals)            First | 1 2 3 4 5 6 7 8 | Last

Biomaterials Science     Full-text available via subscription   (Followers: 3)
Biomedical Engineering     Hybrid Journal   (Followers: 9)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 12)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 3)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 14)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 11)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 4)
Biomedical Microdevices     Hybrid Journal   (Followers: 7)
Biomedizinische Technik - Biomedical Engineering     Full-text available via subscription  
Biomicrofluidics     Open Access   (Followers: 2)
BioNanoMaterials     Full-text available via subscription   (Followers: 1)
Biotechnology Progress     Hybrid Journal   (Followers: 20)
Boletin Cientifico Tecnico INIMET     Open Access  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access  
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Bubble Science, Engineering & Technology     Hybrid Journal  
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 1)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Full-text available via subscription   (Followers: 11)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 12)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 3)
Case Studies in Thermal Engineering     Open Access   (Followers: 1)
Catalysis Communications     Hybrid Journal   (Followers: 4)
Catalysis Letters     Hybrid Journal   (Followers: 1)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 4)
Catalysis Science and Technology     Free   (Followers: 4)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysis Today     Hybrid Journal   (Followers: 6)
CEAS Space Journal     Hybrid Journal   (Followers: 1)
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 2)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 1)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 1)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 1)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 1)
Chinese Journal of Engineering     Open Access  
Chinese Science Bulletin     Open Access  
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access  
Ciencias Holguin     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 10)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 9)
City, Culture and Society     Hybrid Journal   (Followers: 16)
Clay Minerals     Full-text available via subscription   (Followers: 3)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Clinical Science     Full-text available via subscription   (Followers: 3)
Coal Science and Technology     Full-text available via subscription   (Followers: 2)
Coastal Engineering     Hybrid Journal   (Followers: 7)
Coastal Engineering Journal     Hybrid Journal   (Followers: 1)
Coatings     Open Access   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 3)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 4)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 8)
Communications Engineer     Hybrid Journal  
Communications in Information Science and Management Engineering     Open Access   (Followers: 7)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 3)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 7)
Composite Interfaces     Hybrid Journal   (Followers: 3)
Composite Structures     Hybrid Journal   (Followers: 33)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 26)
Composites Part B : Engineering     Hybrid Journal   (Followers: 24)
Composites Science and Technology     Hybrid Journal   (Followers: 32)
Comptes Rendus Mécanique     Full-text available via subscription  
Computation     Open Access   (Followers: 1)
Computational Geosciences     Hybrid Journal   (Followers: 10)
Computational Optimization and Applications     Hybrid Journal   (Followers: 4)
Computational Science and Discovery     Full-text available via subscription  
Computational Water, Energy, and Environmental Engineering     Open Access   (Followers: 1)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 5)
Computers & Geosciences     Hybrid Journal   (Followers: 6)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 4)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 3)
Computers and Geotechnics     Hybrid Journal   (Followers: 5)
Computing and Visualization in Science     Hybrid Journal   (Followers: 3)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 10)
Conciencia Tecnologica     Open Access   (Followers: 1)
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continental Journal of Applied Sciences     Open Access   (Followers: 4)
Continental Journal of Engineering Sciences     Open Access   (Followers: 2)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 3)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 4)
Control Engineering Practice     Hybrid Journal   (Followers: 10)
Control Theory and Informatics     Open Access   (Followers: 4)
Corrosion Science     Hybrid Journal   (Followers: 18)
Corrosion Series     Full-text available via subscription   (Followers: 5)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Dams and Reservoirs     Hybrid Journal   (Followers: 2)
Data Handling in Science and Technology     Full-text available via subscription   (Followers: 2)
Design Journal     Full-text available via subscription   (Followers: 14)
Designed Monomers and Polymers     Hybrid Journal   (Followers: 2)
Designs, Codes and Cryptography     Hybrid Journal   (Followers: 4)
Developments in Clay Science     Full-text available via subscription  

  First | 1 2 3 4 5 6 7 8 | Last

Journal Cover AIChE Journal
   [18 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  [1602 journals]   [SJR: 0.889]   [H-I: 94]
  • Formation of defect-free polyetherimide/PIM-1 hollow fiber membranes for
           gas separation
    • Authors: Lin Hao; Jian Zuo, Tai-Shung Chung
      Pages: n/a - n/a
      Abstract: Dual-layer hollow fiber membranes were produced from blends of Ultem and polymer of intrinsic microporosity (PIM-1) with enhanced gas permeance. The effects of spinning parameters (take-up speed and air gap distance) on gas separation performance were investigated based on the pristine Ultem. Selected spinning conditions were further adopted for the blend system, achieving defect-free and almost defect-free hollow fibers. Adding PIM results in a higher fractional free volume, 50% increments in gas permeance were observed for Ultem/PIM-1 (95/5) and more than 100% increments for Ultem/PIM-1 (85/15). Both O2/N2 and CO2/CH4 selectivities remained the same for Ultem/PIM-1 (95/5) and above 80% of their respective intrinsic values for Ultem/PIM-1 (85/15). The selective layer thickness ranges from 70 to 120 nm, indicating the successful formation of ultrathin dense layers. Moreover, minimum amounts of the expensive material were consumed, that is, 0.88, 1.7, and 2.3 wt % PIM-1 for Ultem/PIM-1 (95/5), (90/10), and (85/15), respectively. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-28T14:09:07.6357-05:00
      DOI: 10.1002/aic.14565
       
  • Model reduction for linear simulated moving bed chromatography systems
           using Krylov-subspace methods
    • Authors: Suzhou Li; Yao Yue, Lihong Feng, Peter Benner, Andreas Seidel-Morgenstern
      Pages: n/a - n/a
      Abstract: Simulated moving bed (SMB) chromatography is a well-established technology for separating chemical compounds. To describe an SMB process, a finite-dimensional multistage model arising from the discretization of partial differential equations is typically employed. However, its relatively high dimension poses severe computational challenges to various model-based analysis. To overcome this challenge, two Krylov-type model order reduction (MOR) methods are proposed to accelerate the computation of the cyclic steady states (CSSs) of SMB processes with linear isotherms. A “straightforward method” that carefully deals with the switching behavior in MOR is first proposed. Its improvement, a “subspace-exploiting method,” thoroughly exploits each reduced model to achieve further acceleration. Simulation studies show that both methods achieve high accuracy and significant speedups. The subspace-exploiting method turns out to be computationally much more efficient. Two challenging analyses of SMB processes, namely uncertainty quantification and CSS optimization, further demonstrate the accuracy, efficiency, and applicability of the proposed methods. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-28T14:03:09.521068-05:
      DOI: 10.1002/aic.14561
       
  • Experimental validation of a flexible modeling approach for distillation
           columns with packings
    • Authors: Christoph Ehlers; Georg Fieg
      Pages: n/a - n/a
      Abstract: The two main concepts for the modeling of distillation columns are the equilibrium-stage (EQ) and the nonequilibrium-stage (NEQ). A model is presented which combines decisive features of both conventional concepts. Based on the idea of a reduced nonequilibrium-stage (RNEQ), this model can be used for the simulation of distillation columns with packings. In contrast to the conventional NEQ approach, this model neglects the influence of liquid side mass-transfer coefficients, which ultimately allows to come up with only one empirical equation describing the overall mass transfer. Thus, a considerable reduction in model complexity is reached, which allows for an efficient consideration of new experimental distillation results. Fitted to experimental data, the model is able to predict, how different pressures and chemical systems might affect the separation efficiency. By comparing calculation results with experimentally determined separation efficiencies for three different packing types, these valuable RNEQ qualities are illustrated. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-24T13:22:23.478698-05:
      DOI: 10.1002/aic.14560
       
  • Mixing potential: A new concept for optimal design of hydrogen and water
           networks with higher disturbance resistance
    • Authors: Zuwei liao; Junyi Lou, Jingdai Wang, Binbo Jiang, Yongrong Yang
      Pages: n/a - n/a
      Abstract: During the last decade, the design methods of hydrogen and water networks have been improved greatly. Since the resulting network structure featuring minimum utility consumption is not unique, other properties such as disturbance resistance have drawn more and more attention. In this article, a novel concept, Mixing Potential, is proposed to improve the disturbance resistance ability of the networks in the design stage. This concept originates from measuring the concentration fluctuation of a single sink, and could be calculated by its graphical and algorithmic definition, respectively. In addition, a sufficient condition for minimizing the Mixing Potential of a single sink has been proved. Based on this sufficient condition, a graphical and its corresponding algorithmic method are proposed to design the hydrogen and water networks with minimum utility consumption. Literature examples illustrate that the disturbance resistance ability of the network can be improved by adjusting the satisfying order of sinks. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-24T13:22:01.598619-05:
      DOI: 10.1002/aic.14556
       
  • Framework for correlating the effect of temperature on nonelectrolyte and
           ionic liquid activity coefficients
    • Authors: Timothy C. Frank; Steven G. Arturo, Bruce S. Holden
      Pages: n/a - n/a
      Abstract: A power-law expression is proposed for correlating the temperature dependence of infinite-dilution activity coefficients ( γij∞) for nonelectrolyte solute–solvent binary pairs and for pairs including an ionic liquid: ln⁡γij∞(at T)/ln⁡γij∞(at Tref)=(Tref/T)θij, where θij = 0 for Lewis–Randall ideal solutions, θij = 1 for classic enthalpy-based Scatchard–Hildebrand regular solution and van Laar models, and −5 
      PubDate: 2014-07-24T13:16:26.501557-05:
      DOI: 10.1002/aic.14557
       
  • Impact of separator’s solid phase ion conductivity parameter on
           convection battery performance and modeling
    • Authors: R. Hilton; M. Gordon, D. Dornbusch, G. J. Suppes
      Pages: n/a - n/a
      Abstract: A solid phase ion conductivity parameter has been added to the separator of a porous electrode theory description of a convection battery performance to increase the accuracy of this model. With the addition of the ion conductivity parameter, the variances between the model and experimental data have been reduced by 80-85% in both the convection cell and the diffusion cell. The parameter is fundamentally consistent with solid phase mechanisms by which ions can transport through separators in parallel with liquid phase transport, and the improved modeling results substantiate the importance of solid or surface ion transport mechanisms at high current fluxes. Modeling was supplemented with dimensionless analysis to lump fundamental parameters that are inherently coupled in the underlying equations. From this analysis, a global parameter has been developed describing the ratio of convective charge transfer to diffusive charge transfer that characterizes the transition from diffusive to convective cell behavior. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-24T01:02:05.521355-05:
      DOI: 10.1002/aic.14568
       
  • Equation-oriented flowsheet simulation and optimization using
           pseudo-transient models
    • Authors: Richard C. Pattison; Michael Baldea
      Pages: n/a - n/a
      Abstract: Tight integration through material and energy recycling is essential to the energy efficiency and economic viability of process and energy systems. Equation-oriented steady state process simulation and optimization are key enablers in the optimal design of integrated processes. In this paper a new process modeling and simulation concept based on pseudo-transient continuation is introduced. We present an algorithm for reformulating the steady-state models of process unit operations as differential-algebraic equation (DAE) systems that are statically equivalent with the original model. We show that these pseudo-transient models improve the convergence of equation-oriented process flowsheet simulations by expanding the convergence basin. We use this concept to build a library of pseudo-transient models for common process unit operations, and show that this modeling concept seamlessly integrates with a previously developed time-relaxation optimization algorithm. Two design case studies are presented to validate the proposed framework. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-24T00:28:29.260326-05:
      DOI: 10.1002/aic.14567
       
  • Structure-property Relationship of pH-sensitive (PCL)2(PDEA-b-PPEGMA)2
           micelles: Experiment and DPD simulation
    • Authors: Wen JingLin; Shu YuNie, Quan Chen, Yu Qian, Xiu FangWen, Li Juan Zhang
      Pages: n/a - n/a
      Abstract: The experiment and dissipative particle dynamics (DPD) simulation were carried out on four polymers with different block ratios for the investigation of the structure-property relationship of (poly(ε-caprolactone)2-[poly(2-(diethylamino)ethyl methacrylate)-b-poly(poly(ethylene glycol) methyl ether methacrylate)]2 [(PCL)2(PDEA-b-PPEGMA)2] micelles. The miktoarm star polymers assembled into spherical micelles composed of PCL core, pH-sensitive PDEA mesosphere and PPEGMA shell. When decreasing pH from 7.4 to 5.0, the hydrodynamic diameter and transmittance of (PCL)2(PDEA-b-PPEGMA)2 micelles increased along with globule-uneven-extended conformational transitions, owing to the protonation of tertiary amine groups of DEA at lower pH conditions. Doxorubicin (DOX) was mainly loaded in the pH-sensitive layer, and more DOX were loaded in the core when increasing drug concentrations. The in vitro DOX release from the micelles was significantly accelerated by decreasing pH from 7.4 to 5.0. The results demonstrated that the pH-sensitive micelles could be used as an efficient carrier for hydrophobic anticancer drugs, achieving controlled and sustained drug release. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-22T03:30:49.283386-05:
      DOI: 10.1002/aic.14562
       
  • Polypropylene in the melt state as a medium for in situ synthesis of
           copper nanoparticles
    • Authors: Humberto Palza; Katherine Delgado, Natalia Moraga, Sing-Hi Wang Molina
      Pages: n/a - n/a
      Abstract: Copper nanoparticles were in situ synthesized into a polypropylene matrix in the melt state. Three different routes were studied depending on the method used for the addition of a copper salt: (1) directly as powder; (2) dissolved in water; and (3) dissolved in water with a reducing agent. The first route produced microcrystal, whereas the second route allowed the synthesis of nanoparticles (∼20 nm) homogeneously dispersed in the polymer matrix. By changing the concentration of the reducing agent in the copper solution (third route), a control of the copper structure in the polymer was possible and salt-based or metal/oxide nanoparticles could be obtained. All these composites were able to release copper ions depending on the characteristic of the nanoparticles present in the polymer. Noteworthy, the resulting polymer/copper composites displayed strong antimicrobial behavior against Escherichia coli. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-21T11:03:38.13524-05:0
      DOI: 10.1002/aic.14549
       
  • Phase Equilibria and Structural Properties of Thiophene/[Bmim][BF4]: A
           Molecular Insight from Monte Carlo Simulations
    • Authors: Yongping Zeng; Chunfeng Wang, Yueyang Xu, Junmei Hu, WenLin Xu, Shengui Ju
      Pages: n/a - n/a
      Abstract: The phase equilibria of thiophene in 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) is calculated by Monte Carlo simulation in Gibbs ensemble using a united atom force field. The liquid density of studied ionic liquid and the vapor pressure of thiophene in [Bmim][BF4] were compared with corresponding experimental data reported in the literature, and a good agreement was obtained. In order to describe the solubility of thiophene in this ionic liquid, we have calculated the radial distribution functions and spatial distribution functions of thiophene/IL mixtures to study the interaction of thiophene with cations and anions of [Bmim][BF4] in the liquid phase. The local composition concept in fluid was also examined to give further insight into the liquid structure. The results show that thiophene is well organized around the terminal carbon atom of the butyl or methyl chain attached to the imidazolium ring of cations and tends to adopt a symmetrically distribution on the anions. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-21T05:24:07.325795-05:
      DOI: 10.1002/aic.14566
       
  • A lattice Boltzmann simulation of mass transport through composite
           membranes
    • Authors: Li-Zhi Zhang
      Pages: n/a - n/a
      Abstract: Composite membranes with a porous support layer and a dense skin layer have been extensively used in gas separation processes. In this study, a new approach, a meso-scale Lattice Boltzmann Simulation approach (LBM), is proposed and used to model the pore-scale gas flow and mass transfer in the inhomogeneous membrane matrixes. Only physical forces are considered. Chemical forces are equivalently converted to physical forces through the relaxation time. Selective permeation of moisture through a composite membrane is modeled. The overall permeability is evaluated. It is found that mass transfer inhomogeneity exists not only in the porous media, but also in the seemingly uniform dense skin layer. Increasing the diffusivity in the skin layer is more effective than decreasing the skin layer thickness in optimizing the overall membrane performance. The new approach gives more detailed insights into the directions for future design of composite membranes for gas separations like air dehumidification. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-19T06:59:00.05676-05:0
      DOI: 10.1002/aic.14564
       
  • The adjustable synergistic effects between acid-base coupling bifunctional
           ionic liquid extractants for rare earth separation
    • Authors: Xiaoqi Sun; Kristian E Waters
      Pages: n/a - n/a
      Abstract: Two of the most widely used industrial extractants for rare earth elements (REEs), i.e., di(2-ethylhexyl)phosphoric acid (HDEHP) and 2-ethyl(hexyl) phosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) were developed into [DEHP]- type acid-base coupling bifunctionalized ionic liquids (ABC-BILs) and [EHEHP]- type ABC-BILs, respectively. The combinations of ABC-BIL extractants revealed obviously synergistic effects for REEs. Seven different combinations of ABC-BILs and five kinds of REEs confirmed the novel synergistic extraction. Some synergy coefficients of the combined ABC-BILs were bigger than those of mixed HDEHP and HEH[EHP] by two orders of magnitude. This paper reports the first synergistic extraction produced by ionic liquid extractants in the field of solvent extraction. The novel synergistic extraction from combined ABC-BILs extractants revealed highly efficient and environmentally friendly potential in both of academic research and industrial application for REEs separation. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-19T03:06:18.682879-05:
      DOI: 10.1002/aic.14563
       
  • Microwave assisted flow synthesis: Coupling of electromagnetic and
           hydrodynamic phenomena
    • Authors: Narendra G. Patil; Faysal Benaskar, Jan Meuldijk, Lumbertus A. Hulshof, Volker Hessel, Jaap C. Schouten, Erik D. C. Esveld, Evgeny V. Rebrov
      Pages: n/a - n/a
      Abstract: This article describes the results of a modeling study performed to understand the microwave heating process in continuous-flow reactors. It demonstrates the influence of liquid velocity profiles on temperature and microwave energy dissipation in a microwave integrated milli reactor-heat exchanger. Horizontal cocurrent flow of a strong microwave absorbing reaction mixture (ethanol + acetic acid, molar ratio 5:1) and a microwave transparent coolant (toluene) was established in a Teflon supported quartz tube (i.d.: 3 × 10−3 m and o.d.: 4 × 10−3 m) and shell (i.d.: 7 × 10−3 m and o.d.: 9 × 10−3 m), respectively. Modeling showed that the temperature rise of the highly microwave absorbing reaction mixture was up to four times higher in the almost stagnant liquid at the reactor walls than in the bulk liquid. The coolant flow was ineffective in controlling the outlet reaction mixture temperature. However, at high flow rates it limits the overheating of the stagnant liquid film of the reaction mixture at the reactor walls. It was also found that the stagnant layer around a fiber optic temperature probe, when inserted from the direction of the flow, resulted in much higher temperatures than the bulk liquid. This was not the case when the probe was inserted from the opposite direction. The experimental validations of these modeling results proved that the temperature profiles depend more on the reaction mixture velocity profiles than on the microwave energy dissipation/electric field intensity. Thus, in flow synthesis, particularly where a focused microwave field is applied over a small tubular flow reactor, it is very important to understand the large (direct/indirect) influence of reactor internals on the microwave heating process. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-18T13:35:33.306397-05:
      DOI: 10.1002/aic.14552
       
  • A novel hybrid feedstock to liquids and electricity process: Process
           modeling and exergoeconomic life cycle optimization
    • Authors: Chang He; Fengqi You, Xiao Feng
      Pages: n/a - n/a
      Abstract: This article proposes a novel hybrid low-rank coal (LRC)/biomass/natural gas process for producing liquid fuels and electricity. The hybrid process highlights coexistence of indirect and direct liquefaction technologies, cogasification of char and biomass, and corefinery of LRC syncrude and Fischer–Tropsch syncrude. A process simulation based on detailed chemical kinetics is present to illustrate its feasibility. In addition, we propose an exergoeconomic life cycle optimization framework that seeks to maximize the primary exergy saving ratio, primary total overnight cost saving ratio, life cycle waste emissions avoidance ratio, and primary levelized cost saving ratio by comparing the proposed hybrid process to its reference stand-alone subsystems. From the results, we can determine four optimal designs which yield competitive breakeven oil prices ranging from $1.87/GGE to $2.13/GGE. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-18T13:32:34.589941-05:
      DOI: 10.1002/aic.14551
       
  • Enhancement of flux and solvent stability of Matrimid® thin-film
           composite membranes for organic solvent nanofiltration
    • Authors: Shi-Peng Sun; Tai-Shung Chung, Kang-Jia Lu, Sui-Yung Chan
      Pages: n/a - n/a
      Abstract: The development of high flux and solvent-stable thin-film composite (TFC) organic solvent nanofiltration (OSN) membranes was reported. A novel cross-linked polyimide substrate, consisting of a thin skin layer with minimum solvent transport resistance and a sponge-like sublayer structure that could withstand membrane compaction under high-pressure was first fabricated. Then the solvent flux was significantly enhanced without compromising the solute rejection by the coupling effects of (1) the addition of triethylamine/camphorsulfonic acid into the monomer solution, and (2) the combined post-treatments of glycerol/sodium dodecyl sulphate immersion and dimethyl sulfoxide (DMSO) filtration. Finally, the long-term stability of the TFC membrane in aprotic solvents such as DMSO was improved by post-crosslink thermal annealing. The novel TFC OSN membrane developed was found to have superior rejection to tetracycline (MW: 444 g/mol) but was very permeable to alcohols such as methanol (5.12 lm−2h−1bar−1) and aprotic solvents such as dimethylformamide (3.92 lm−2h−1bar−1) and DMSO (3.34 lm−2h−1bar−1). © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-18T11:07:45.512646-05:
      DOI: 10.1002/aic.14558
       
  • Reconstruction of transcription factor profiles from fluorescent protein
           reporter systems via dynamic optimization and Tikhonov regularization
    • Authors: Wei Dai; Juergen Hahn, Jia Kang
      Pages: n/a - n/a
      Abstract: This work presents a generally applicable technique for reconstructing transcription factor (TF) profiles from fluorescence microscopy images of green fluorescent protein reporter systems. The approach integrates dynamic optimization and a Tikhonov regularization to avoid over-fitting caused by the highly ill-conditioned structure of this inverse problem. The advantage that the presented approach has over existing methods is that no assumptions are made about the TF profile, the linearity, or lack thereof, of the dynamic model used, and the sampling time of the measurements. Moreover, the method allows to use discretization times for the model different from the measurement sampling times and can also deal with state constraints. The technique has been applied to both simulated and experimental data where the profile of the TFs NF-κB and STAT3 are reconstructed. In both of the case studies, the presented approach exhibits excellent performance while fewer assumptions are needed than for existing techniques. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-18T11:04:28.555781-05:
      DOI: 10.1002/aic.14559
       
  • Effect of impeller design and power consumption on crystal size
           distribution
    • Authors: Chinmay V. Rane; Kalekudithi Ekambara, Jyeshtharaj B. Joshi, Doraiswami Ramkrishna
      Pages: n/a - n/a
      Abstract: Crystallization processes in a 500 mL stirred tank crystallizer with computational fluid dynamics (CFD) and population balances toward estimating how crystal size distributions (CSDs) are influenced by flow inhomogeneities was explored. The flow pattern and CSD are presented here though extensive phase Doppler particle analyzer measurements and CFD predictions for three different impeller designs (disc turbine, pitched blade turbine, and Propeller) and each rotated at three different speeds (2.5, 5, and10 r/s). As crystallization processes in practice could involve break-up and aggregation of crystals, some selected break-up and aggregation kernels are incorporated. Extensive comparison of simulations with experimental data showed consistent trends in the proper quantitative range. An attempt has also been made to develop scaling laws: (a) mean particle size with average power consumption per unit mass and (b) particle-size distribution with the turbulent energy dissipation distribution. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-16T14:14:53.653545-05:
      DOI: 10.1002/aic.14541
       
  • Comparison of wash-coated monoliths vs. microfibrous entrapped catalyst
           structures for catalytic VOC removal
    • Authors: Sabrina Wahid; Donald R. Cahela, Bruce J. Tatarchuk
      Pages: n/a - n/a
      Abstract: Head-to-head experimental performance comparisons for flow through pleated microfibrous structures (flat-, V-, and W-shaped) were made with wash-coated monolith of different cells per square inch (230 and 400). Microfibrous entrapped catalyst (MFEC) was prepared by entrapping support particles (γ-Al2O3, 150–250 μm diameter) into nickel microfibers. Pleated structures of MFECs and wash-coated monoliths containing Pd-Mn/γ-Al2O3 were investigated systematically for volatile organic compound (e.g., ethanol) removal at various face velocities (ca. 3–30 m/s) and at low temperatures (≤473 K). The experimental studies showed that pleated MFEC (W-shaped) had shown significantly improved performance in VOC removal in terms of conversion and pressure drop than tested monolith for high face velocity system. The flexibility of pleating lowered the effective velocity inside the media that resulted lower pressure drop and higher conversion. Furthermore, a reaction kinetic model was developed for pleated MFEC considering the Peffer's model to substantiate the experimental results. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-15T16:16:32.634213-05:
      DOI: 10.1002/aic.14555
       
  • Kinetic study of retro-aldol condensation of glucose to glycolaldehyde
           with ammonium metatungstate as the catalyst
    • Authors: Junying Zhang; Baolin Hou, Aiqin Wang, ZhenLei Li, Hua Wang, Tao Zhang
      Pages: n/a - n/a
      Abstract: The kinetics of the retro-aldol condensation of glucose to glycolaldehyde was studied in a batch reactor at 423–453 K using ammonium metatungstate (AMT) as the catalyst. Three consecutive reactions were considered: retro-aldol condensation of glucose to erythrose and glycolaldehyde (R1), retro-aldol condensation of erythrose to two moles of glycolaldehyde (R2), and further conversion of glycolaldehyde to side products (R3). Fitting of the experimental data showed that R1 was first-order reaction while R2 and R3 were 1.7th- and 2.5th-order reaction, respectively. Conversely, the reaction rate of R1 was 0.257th-order dependence on the concentration of AMT catalyst. The apparent activation energies for R1, R2, and R3 were 141.3, 79.9, and 52.7 kJ/mol, respectively. The high activation energy of R1 suggests that a high temperature is favorable to the formation of glycolaldehyde. The experimental C–t curves at different temperatures and initial glucose concentrations were well predicted by the kinetic model. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-15T14:08:43.897286-05:
      DOI: 10.1002/aic.14554
       
  • Flow and temperature patterns in an inductively coupled plasma reactor:
           Experimental measurements and CFD simulations
    • Authors: Sangeeta B. Punjabi; Sunil N. Sahasrabudhe, S. Ghorui, A. K. Das, Narendra K. Joshi, Dushyant C. Kothari, Arijit A. Ganguli, Jyeshtharaj B. Joshi
      Pages: n/a - n/a
      Abstract: Measurements of temperature patterns in an inductively coupled plasma (ICP) have been carried out experimentally. Plasma torch was operated at different RF powers in the range of 3–14 kW at near atmospheric pressure and over a wide range of sheath gas flow rate (3–25 lpm). Measurements were made at five different axial positions in ICP torch. The chordal intensities were converted into a radial intensity profile by Abel Inversion technique. Typical radial temperature profile shows an off-axis temperature peak, which shifts toward the wall as the power increases. Temperatures in the range of 6000–14,000 K were recorded by this method. The temperature profiles in the plasma reactor were simulated using computational fluid dynamics (CFD). A good agreement was found between the CFD predictions of the flow and temperature pattern with those published in the literature as well as the temperature profiles measured in the present work. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-15T14:07:42.877996-05:
      DOI: 10.1002/aic.14547
       
  • High-throughput packed-bed microreactors with in-line analytics for the
           discovery of asphaltene deposition mechanisms
    • Authors: Chuntian Hu; Ryan L. Hartman
      Pages: n/a - n/a
      Abstract: Understanding asphaltene nanoaggregation kinetics is a key to predicting the deposition in pure quartz-grain porous media. High-throughput quartz packed-bed microreactors (μPBRs) were, therefore, designed to provide mechanistic insights by merging oilfield chemistry and microchemical systems. In-line UV-Vis spectroscopy and pressure transducer were used to characterize the stable packing of quartz particles with porosity of ∼40% and permeability of ∼5.5 × 10−13 m2. Temperature (25.0–90.0°C), n-heptane composition (50.0–80.0 vol %), and n-alkane (n-C5 to n-C9) were all observed to influence asphaltenes deposition in the porous media, and reduced dispersion was obtained in the damaged packed-bed by estimating dispersion coefficients and the Bodenstein number. Deposition by mechanical entrapment dominated the mechanism in all scenarios, as discovered by the simplified Kozeny–Carman and Civan's permeability-porosity relationships. The results could aid in the design of remediations that minimize production losses of considerable economic magnitude. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-10T12:57:05.481004-05:
      DOI: 10.1002/aic.14542
       
  • Atomic layer deposition of polyimide on microporous polyethersulfone
           membranes for enhanced and tunable performances
    • Authors: Ting Sheng; He Chen, Sen Xiong, Xiaoqiang Chen, Yong Wang
      Pages: n/a - n/a
      Abstract: Atomic layer deposition (ALD) of polyimide (PI) is explored to tune the separation properties of microporous polyethersulfone (PES) membranes and also to improve their mechanic and thermal stability. Conformal and uniform thin layers of PI are deposited along the pore wall throughout the entire PES membrane instead of forming a top layer merely on the membrane surface. With increasing ALD cycles, the pore size of the PES membrane is progressively reduced, leading to increased retention. The permeation is correspondingly decreased but its drop is less pronounced than the increase of retention. For example, the retention to 23-nm silica nanospheres is significantly increased from nearly zero to 60% after 3000 ALD cycles, whereas the water flux is moderately decreased by 54%. Moreover, ALD of PI evidently enhances the mechanical strength and thermal resistance of the PES membrane as PI tightly wraps the skeleton of the membrane. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-10T12:37:53.431256-05:
      DOI: 10.1002/aic.14553
       
  • Gas–liquid flow modeling in columns equipped with structured packing
    • Authors: Cyprien Soulaine; Pierre Horgue, Jacques Franc, Michel Quintard
      Pages: n/a - n/a
      Abstract: The modeling of gas–liquid flow in distillation columns equipped with structured packing has been dealt. The devices are seen as bistructured porous media, and a macroscale model is proposed taking into account this specific geometry. In this model, the two liquid films, one-per-sheet, are treated separately and are allowed to exchange matter at the vicinity of the contact points between corrugated sheets. The model emphasizes mechanisms that lead to the liquid radial dispersion effects: a main part comes from the geometry itself, another part is due to the capillary effects. A particular attention is paid to model these phenomena from a macroscale point of view. Finally, the simulation results are confronted to tomography imaging within a lab-scale column and show a qualitative good agreement of the liquid distribution. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-10T12:36:00.74958-05:0
      DOI: 10.1002/aic.14550
       
  • Kinetics of CO2 absorption by aqueous 3-(methylamino)propylamine
           solutions: Experimental results and modeling
    • Authors: Juliana G. M.-S. Monteiro; Saddam Hussain, Hammad Majeed, Emmanuel O. Mba, Ardi Hartono, Hanna Knuutila, Hallvard F. Svendsen
      Pages: n/a - n/a
      Abstract: Experimental data and a model for the initial kinetics of CO2 into 3-(methylamino)propylamine (MAPA) solutions are presented in work. MAPA has been tested as an activator for tertiary amines with encouraging results. The measurements were performed in a string of discs contactor and, as no initial kinetics data are available in literature, additional measurements were carried out and in a wetted wall column. The obtained overall mass-transfer coefficients from both apparatuses are in reasonable agreement. To obtain values for the observed kinetic constant, kobs, the experimental results were interpreted using a two-film mass-transfer model and invoking the pseudo-first order assumption. Needed experimental values for density, viscosity, and Henry's law coefficient for CO2 were measured and are given. The results indicate that MAPA is almost twice as fast as piperazine, eight times faster than 2-(2-aminoethyl-amino)ethanol (AEEA), and 15 times faster than monoethanolamine, when comparing unloaded 1 M solutions at 25°C. The observed kinetic constant was modeled using the direct mechanism. The final expression for kobs can be applied for any concentration and temperature within the experimental data range, and, together with the presented physical data, comprises a complete model for calculating absorption fluxes. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-09T17:38:37.973748-05:
      DOI: 10.1002/aic.14546
       
  • Continuous electroreduction of CO2 to formate using Sn gas diffusion
           electrodes
    • Authors: Andrés Del Castillo; Manuel Alvarez-Guerra, Angel Irabien
      Pages: n/a - n/a
      Abstract: Electrochemical valorization may be a strategy for mitigating climate change, as the process allows for CO2 to be converted into industrially useful chemicals. The aim of this work is to study the influence of key variables on the performance of an experimental system for continuous electroreduction of CO2 to formate with a gas diffusion electrode (GDE) loaded with Sn. A 23 factorial design of experiments at different levels of current density (j), electrolyte flow rate/electrode area ratio (Q/A ratio) and GDE Sn load was followed. Higher rates and concentrations (i.e., 1.4·10−3 mol m−2 s−1 and 1348 mg L−1 with efficiencies of approximately 70%) were obtained with GDEs than with plate electrodes. The statistical design of experiments demonstrated that the Sn load had the most significant effect on rate and efficiency. However, despite these promising results, further research is required to optimize the process. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-05T19:11:25.124982-05:
      DOI: 10.1002/aic.14544
       
  • Optimization Models for Shale Gas Water Management
    • Authors: Linlin Yang; Jeremy Manno, Ignacio E. Grossmann
      Abstract: There are four key aspects for water use in hydraulic fracturing, including source water acquisition, wastewater production, reuse and recycle, and subsequent transportation, storage, and disposal. This work optimizes water use life cycle for wellpads through a discrete-time two-stage stochastic mixed-integer linear programming model under uncertain availability of water. The objective is to minimize expected transportation, treatment, storage, and disposal cost while accounting for the revenue from gas production. Assuming freshwater sources, river withdrawal data, location of wellpads and treatment facilities as given, the goal is to determine an optimal fracturing schedule in coordination with water transportation, and its treatment and reuse. The proposed models consider a long time horizon and multiple scenarios from historical data. Two examples representative of the Marcellus Shale play are presented to illustrate the effectiveness of the formulation, and to identify optimization opportunities that can improve both the environmental impact and economical use of water. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-13T02:52:57.364714-05:
      DOI: 10.1002/aic.14526
       
  • A mechanistic growth model for inorganic crystals: Growth mechanism
    • Authors: Preshit Dandekar; Michael F. Doherty
      Abstract: Inorganic crystals grown from solution find wide application. We present a mechanistic growth model based on the spiral growth mechanism that operates at low supersaturation on inorganic crystal surfaces. The long-range electrostatic interactions on inorganic crystal surfaces are captured by methods developed in our previous paper1. The interactions of kink site growth units with the solvent molecules partially determine the growth kinetics. Relevant experimental parameters are systematically accounted for in the expression for the kink incorporation rate along step edges on the crystal surfaces. The growth model accurately predicts the asymmetric growth spirals on the (101¯4) surface of calcite crystals. The effect of supersaturation and ionic activity ratio on the step velocities of the acute and obtuse spiral edges is correctly captured. This model can be used to predict the shapes of solution grown inorganic crystals and to engineer the growth process to design inorganic solids with functionally desirable shapes. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-05-28T08:30:09.968276-05:
      DOI: 10.1002/aic.14513
       
  • Inverse methods for material design
    • Authors: Avni Jain; Jonathan A. Bollinger, Thomas M. Truskett
      Pages: 2732 - 2740
      PubDate: 2014-05-21T11:45:27.372022-05:
      DOI: 10.1002/aic.14491
       
  • Confirmation of predicted activity for factor XIa inhibitors from a
           virtual screening approach
    • Authors: Hang Li; Donald P. Visco, Nic D. Leipzig
      First page: 2741
      Abstract: High-throughput screening approaches, where hundreds of thousands of compounds are evaluated in microamounts for their activity against certain targets, can regularly result in hit rates that are only a fraction of a percent. Here, we take a previously developed machine-learning classification model (with the Signature molecular descriptor) used to identify active compounds against Factor XIa and experimentally verify the virtual screening model predictions. Of 21 predicted compounds tested, seven show activity against Factor XIa, a 33% hit rate. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-02T16:08:23.924325-05:
      DOI: 10.1002/aic.14508
       
  • MOF-derived porous carbon for adsorptive desulfurization
    • Authors: Yawei Shi; Xiangwen Zhang, Li Wang, Guozhu Liu
      First page: 2747
      Abstract: ZIF-8, a typical and popular type of MOFs, was synthesized and carbonized directly to produce highly porous carbon without washing or activation. The resulting carbon was found to be a promising candidate for adsorption desulfurization of DBT with a maximum adsorption capacity of 26.7mgS/g in the concentration range below 174ppmS, and the adsorption capacity decreased ~17% with the addition of 10% para-xylene. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-17T14:54:33.44644-05:0
      DOI: 10.1002/aic.14525
       
  • Durable superoleophobic fabric surfaces with counterintuitive
           superwettability for polar solvents
    • Authors: Shuaijun Pan; Rui Guo, Weijian Xu
      First page: 2752
      Abstract: Surfaces with special wetting properties have been attracting world-wide scientific interests in recent years due to their desirable practical applications.1-6 A surface is considered to be superoleophobic (SOP) if the apparent contact angle θ* for a contacting low surface tension oil droplet is greater than 150°.7 While a few superoleophobic surfaces have been previously engineered,8-10 there are very few stimuli-responsive superoleophobic surfaces reported displaying switchable oil wetting properties11-12 and even significantly fewer13-14 functioning as a both superoleophobic and superhydrophilic (SHL, θ*water ˜ 0°) coating in air. In this work, we have fabricated remarkably durable smart surfaces that, for the first time, exhibit clever solvent-responsiveness of extreme wetting behaviors that display both superoleophobicity with a wide surface tension range of nonpolar oils and quickly switch to counterintuitive superwettability with virtually all the contacting polar liquids. Our smart surfaces, allowing nonpolar oil liquids, even for ultra-low surface tension gasoline, such as hexane (18.5 mN m-1) and heptane (20.6 mN m-1), to easily bead up on the surface with a robust extreme oil-repellent composite Cassie-Baxter state15, can cleverly and spontaneously manifest fully wetted Wenzel state16 displaying apparent contact angles of about 0° for almost all the aprotic and protic polar solvents covering an extensive range of surface tension, thus permitting such liquids like water (72.8 mN m-1), dimethylformamide (37.4 mN m-1) and ethanol (22.1 mN m-1) to readily spread and permeate through. Such a clever solvent-responsive wetting and de-wetting ability, thereby, make our surfaces ideal candidates not only for effective oil shielding but for highly energy-efficient surface self-cleaning17-18 and oil-water separations13,19. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-18T19:11:31.796655-05:
      DOI: 10.1002/aic.14517
       
  • An efficient and eco-friendly solution-chemical route for preparation of
           ultrastable reduced graphene oxide suspensions
    • Authors: Dafang He; Liming Shen, Xiaoyan Zhang, Yifeng Wang, Ningzhong Bao, Harold H. Kung
      Pages: 2757 - 2764
      Abstract: We describe a facile and eco-friendly solution approach to chemically reduce graphene oxide (GO) to high-quality graphene using nontoxic inexpensive reductants. The reduction process and mechanism of a group of eco-friendly reductants were systematically studied. These reductants perform quite differently in terms of reduction rate (l-ascorbic acid [l-AA] > d-fructose > sucrose > glucose > sodium sulfite), density of small sp2 domains (l-AA > sodium sulfite > glucose > sucrose > d-fructose), degree of reduction (l-AA > glucose > d-fructose > sodium sulfite > sucrose), and stability of the reduced GO suspension (l-AA > d-fructose > sucrose > glucose > sodium sulfite). l-AA shows the highest reducing ability, achieving the largest extent of reduction after 10 min in the presence of ammonia. Both residual oxygen functionalities and the adsorbed oxidization products of l-AA on the graphene surface are responsible for stabilizing the reduced GO suspension over several months. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2757–2764, 2014
      PubDate: 2014-05-29T21:48:53.157989-05:
      DOI: 10.1002/aic.14499
       
  • Mechanical stability of monolithic catalysts: Factors affecting washcoat
           adhesion and cohesion during preparation
    • Authors: Dongfang Wu; Shangshang Kong, Hua Zhang, Yongdan Li
      Pages: 2765 - 2773
      Abstract: Alumina-washcoated cordierite monoliths are prepared to investigate the effects of the preparation process factors on the mechanical stability of monolithic catalysts. It is shown that the agent for pretreating substrates, properties of the washcoating solution (solid content, additive, and amount of additive), and washcoating times all have great effects on the washcoat loading and on the washcoat adhesion and cohesion. There is a great possibility of improving the mechanical stability through the optimization of these factors. If multiple washcoating is performed, the two-time washcoating after calcination is recommended in this case. It is also pointed out that the minor variation of the washcoat loading with monolithic mini-specimen increases the scatter of the washcoat adhesion and cohesion, resulting from fatigue failure of active material. Furthermore, the previously proposed mechanical failure mechanism is confirmed to be an effective tool to factors analysis of the mechanical stability of cordierite monolithic catalysts. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2765–2773, 2014
      PubDate: 2014-05-08T11:14:13.645999-05:
      DOI: 10.1002/aic.14480
       
  • Influence of environmental conditions on caking mechanisms in individual
           amorphous food particle contacts
    • Authors: Christine I. Haider; Michael J. Hounslow, Agba D. Salman, Tim O. Althaus, Gerhard Niederreiter, Stefan Palzer
      Pages: 2774 - 2787
      Abstract: Caking of amorphous powders creates severe problems such as product loss and additional costs in the food industry. Among the main factors causing this unwanted agglomeration process are fluctuations of the environmental conditions, that is, a rise in temperature and humidity. There is correspondingly a need to identify and, if possible, avoid the environmental conditions inducing strong interparticle cohesion based on particle contact mechanisms like viscoelastic flattening and sintering. For this reason, a novel micromanipulation approach focusing on the interactions between individual amorphous food particles in contact under load in a controlled environment is introduced. It was possible to identify the dominant caking mechanism under defined conditions, such as temperature and humidity, particle deformation, as well as contact holding time, and to quantify interparticle cohesion. Furthermore, the mechanical behavior of rubbery spherical model particles is presented and a theoretical approach to describe the contact zone formation kinetics is proposed. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2774–2787, 2014
      PubDate: 2014-05-21T13:17:32.16952-05:0
      DOI: 10.1002/aic.14490
       
  • Particle-scale investigation of the solid dispersion and residence
           properties in a 3-D spout-fluid bed
    • Authors: Shiliang Yang; Kun Luo, Jianren Fan, Kefa Cen
      Pages: 2788 - 2804
      Abstract: Three-dimensional modeling of the gas–solid flow in a spout-fluid bed is conducted at the particle-scale level. Both the local and systematic dispersion behaviors of solid phase are initially investigated. Then, the solid circulating and resident behaviors are discussed. The results demonstrate that vigorously lateral solid dispersion appears in the spout region and the periphery of the fountain, whereas intensely vertical dispersion exists in the central region of the bed. Moreover, the inlet configuration of bed strongly affects the distribution of lateral dispersion, while its influence on the vertical one disappears in the fountain. Strong anisotropy of solid dispersion along the three directions is obtained. Systematic dispersion intensity along the vertical direction is an order of magnitude larger than the lateral one. In addition, two circulating patterns of solid phase can be identified. Solid residence time is the smallest in the spout region and the largest in the bottom corner. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2788–2804, 2014
      PubDate: 2014-05-21T11:46:18.398397-05:
      DOI: 10.1002/aic.14494
       
  • Fault detection and isolation in hybrid process systems using a combined
           data-driven and observer-design methodology
    • Authors: Chudong Tong; Nael H. El-Farra, Ahmet Palazoglu, Xuefeng Yan
      Pages: 2805 - 2814
      Abstract: A combined data-driven and observer-design methodology for fault detection and isolation (FDI) in hybrid process systems with switching operating modes is proposed. The main contribution is to construct a unified framework for FDI by integrating Gaussian mixture models (GMM), subspace model identification (SMI), and results from unknown input observer (UIO) theory. Initially, a GMM is built to identify and describe the multimodality of hybrid systems using the recorded input/output process data. A state-space model is then obtained for each specific operating mode based on SMI if the system matrices are unknown. An UIO is designed to estimate the system states robustly, based on which the fault detection is laid out through a multivariate analysis of the residuals. Finally, by designing a set of unknown input matrices for specific fault scenarios, fault isolation is performed through the disturbance-decoupling principle from the UIO theory. A significant benefit of the developed framework is to overcome some of the limitations associated with individual model-based and data-based approaches in dealing with the problem of FDI in hybrid systems. Finally, the validity and effectiveness of the proposed monitoring framework are demonstrated using a numerical example, a simulated continuous stirred tank heater process, and the Tennessee Eastman benchmark process. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2805–2814, 2014
      PubDate: 2014-04-30T11:29:40.999333-05:
      DOI: 10.1002/aic.14475
       
  • Regularization-based statistical batch process modeling for final product
           quality prediction
    • Authors: Zhengbing Yan; Chih-Chiun Chiu, Yuan Yao, Weiwei Doing
      Pages: 2815 - 2827
      Abstract: Prediction accuracy and model interpretation are two important aspects with regard to regression models. In the field of statistical modeling of chemical batch processes, most research focuses on prediction accuracy, while the importance of the latter aspect is often overlooked. In multiphase batch processes, it is possible that only a few phases are relevant to certain quality indices, while different time points belonging to the same relevant phase usually have similar contribution to the quality. The regression coefficients of batch process model should reflect such process characteristics, that is, the coefficients corresponding to the irrelevant phases should be close to zero, while the coefficients of each variable within the same phase should vary smoothly. In this study, regularization techniques are introduced to statistical modeling of chemical batch processes to achieve both accurate prediction and good interpretation. The application to an injection molding process shows the feasibility of the proposed methods. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2815–2827, 2014
      PubDate: 2014-04-30T11:07:05.235818-05:
      DOI: 10.1002/aic.14476
       
  • Modeling and Bayesian parameter estimation for semibatch pH-shift reactive
           crystallization of l-glutamic acid
    • Authors: Qing-Lin Su; Min-Sen Chiu, Richard D. Braatz
      Pages: 2828 - 2838
      Abstract: A mathematical model for semibatch pH-shift reactive crystallization of l-glutamic acid is developed that takes into account the effects of protonation and deprotonation in the species balance of glutamic acid, crystal size distribution, polymorphic crystallization, and nonideal solution properties. The crystallization mechanisms of  α- and β-forms of glutamic acid are addressed by considering primary and secondary nucleation, size-dependent growth rate, and mixing effects on nucleation. The kinetic parameters are estimated by Bayesian inference from batch experimental data collected from literature. Probability distributions of the estimated parameters in addition to their point estimates are obtained by Markov Chain Monte Carlo simulation. The first-principles model is observed in good agreement with the experimental data and can be further used for model predictions in robust control strategies. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2828–2838, 2014
      PubDate: 2014-05-08T11:27:45.386944-05:
      DOI: 10.1002/aic.14481
       
  • Temperature distribution reconstruction in Czochralski crystal growth
           process
    • Authors: Javad Abdollahi; Mojtaba Izadi, Stevan Dubljevic
      Pages: 2839 - 2852
      Abstract: A mechanical geometric crystal growth model is developed to describe the crystal length and radius evolution. The crystal radius regulation is achieved by feedback linearization and accounts for parametric uncertainty in the crystal growth rate. The associated parabolic partial differential equation (PDE) model of heat conduction is considered over the time-varying crystal domain and coupled with crystal growth dynamics. An appropriately defined infinite-dimensional representation of the thermal evolution is derived considering slow time-varying process effects. The computational framework of the Galerkin's method is used for parabolic PDE order reduction and observer synthesis for temperature distribution reconstruction over the entire crystal domain. It is shown that the proposed observer can be utilized to reconstruct temperature distribution from boundary temperature measurements. The developed observer is implemented on the finite-element model of the process and demonstrates that despite parametric and geometric uncertainties present in the model, the temperature distribution is reconstructed with the high accuracy. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2839–2852, 2014
      PubDate: 2014-05-21T11:40:54.5396-05:00
      DOI: 10.1002/aic.14486
       
  • Optimal interplant water networks for industrial zones: Addressing
           interconnectivity options through pipeline merging
    • Authors: Sabla Y. Alnouri; Patrick Linke, Mahmoud El-Halwagi
      First page: 2853
      Abstract: To date, alternative design options that exist for interconnecting transmission and distribution networks have not been considered in water reuse network synthesis. Existing approaches that do incorporate piping expenses in the design of interplant water networks assign a separate pipeline for every water allocation. However, merging together common pipeline regions for the transmission of water from, or to nearby but different processing facility destinations may improve the overall water network performance not only in terms of cost efficiency but also in terms of complexity. A novel approach that is capable of accounting for pipeline merging scenarios that could exist within a water reuse network is introduced in this article. Two different pipeline branching possibilities have been introduced in this work, for the purpose of merging: (1) forward branching and (2) backward branching. The approach is implemented for the design of interplant water networks considering direct water reuse amongst several coexisting processing facilities within an industrial zone. A case study is presented to illustrate the application of the approach and its benefits. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-11T15:14:00.52872-05:0
      DOI: 10.1002/aic.14516
       
  • Transient adsorption studies of automotive hydrocarbon traps
    • Authors: Jing Luo; Robert W. McCabe, Mark A. Dearth, Raymond J. Gorte
      Pages: 2875 - 2881
      Abstract: A chromatographic adsorption unit was designed and built to study the adsorption of alkanes in zeolites for the hydrocarbon trap systems in three-way catalysts, to assist in the selection of optimal materials for this application. The experimental apparatus used a zeolite bed in place of the column in an ordinary gas chromatograph and could be accurately modeled to determine the adsorption equilibrium constants for simple alkanes in MFI zeolites. The adsorption of iso-pentane was studied in BEA zeolites with varying Si/Al2 ratios, before and after ex situ zeolite aging simulating engine exhaust, and in the presence of water vapor. The elution times were shown to depend directly on the zeolite adsorption capacity. The primary effect of water was to decrease the iso-pentane adsorption capacity by partial filling of the zeolite pores through adsorption of water at acid sites. Some implications of this work for choosing the best materials for hydrocarbon trapping are discussed. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2875–2881, 2014
      PubDate: 2014-04-25T22:29:11.057975-05:
      DOI: 10.1002/aic.14477
       
  • Fluidized bed synthesis of carbon nanotubes: Reaction mechanism, rate
           controlling step and overall rate of reaction
    • Authors: Kinshuk Dasgupta; Jyeshtharaj B. Joshi, Harvinderpal Singh, Srikumar Banerjee
      Pages: 2882 - 2892
      Abstract: Carbon nanotubes have been synthesized from acetylene and methane in a fluidized bed by using ferrocene as the catalyst dispersed over carbon black support material. The agglomerate size of carbon black, loading of catalyst, total gas flow rate, partial pressure of reactant gas, temperature of synthesis, and time of synthesis have been varied to understand their effects on the yield of carbon nanotubes. A reaction mechanism consisting of eleven steps and the rate equations for these steps have been proposed. Formation of carbon molecules on the catalyst surface was found to be the rate controlling step in the temperature range of 700–807°C, with an activation energy 47 kJ mol−1, while diffusion through pores in the carbon black was found to be the rate controlling step in the temperature range of 807–1000°C with an activation energy of 7.6 kJ mol−1. A continuous deactivation of the catalyst, represented by an exponential decay, was observed. The products have been characterized by thermogravimetry, electron microscopy, and Raman spectroscopy. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2882–2892, 2014
      PubDate: 2014-05-09T14:59:33.733414-05:
      DOI: 10.1002/aic.14482
       
  • Generalized model of heat transfer and volatiles evolution inside
           particles for coal devolatilization
    • Authors: Binhang Yan; Yan Cheng, Pengcheng Xu, Chenxi Cao, Yi Cheng
      Pages: 2893 - 2906
      Abstract: Devolatilization is acknowledged as the first important step in coal conversion techniques. A comprehensive heat transfer and devolatilization model was established, with special consideration of the particle-scale physics and chemistry, to predict the internal heat transport and pyrolysis behavior of particles. The chemical percolation devolatilization model with corrected kinetic parameters and structure parameters was validated with a lot of experimental data and then adopted to describe the devolatilization behaviors under a broader range of temperatures, heating rates, and coal types. The newly achieved understanding of the integrated effect of heating rate and coal type on coal devolatilization could help to provide a preliminary coal rank selection method for industrial processes. In particular, in-depth discussion of the influences of heat conduction, volatiles diffusion, and endothermic heat of devolatilization inside particle indicated the dominant roles of these factors when the intensity of heat transfer was strong or the release of volatiles was rapid. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2893–2906, 2014
      PubDate: 2014-05-09T15:40:57.987155-05:
      DOI: 10.1002/aic.14484
       
  • Unsupported nickel catalysts for methane catalytic decomposition into pure
           hydrogen
    • Authors: Lu Zhou; Yu Guo, Kameyam Hideo
      Pages: 2907 - 2917
      Abstract: Catalytic decomposition of methane to pure hydrogen is a reaction of crucial importance for clean energy, if the problem of catalyst separation is solved and the carbon material has an increased commercial value. Unsupported nickel catalysts were synthesized by fusion method. The catalyst derived from nickel nitrate forms heterogeneous octahedral NiO, whereas the nickel hydroxide precursor results in catalyst containing sponge-like NiO with folding lamellar structure of high porosity. The catalysts reactivity test was conducted with a fixed bed system at 1073 K. The catalyst subjected to hydrogen prereduction proved to be inactive. However, the methane prereduction was found to produce some coke to disperse the Ni particles and thus activated the catalyst. It was found that the higher concentration of methane resulted in a better methane conversion, but a higher deactivation rate. Carbon growth models were formulated to explain the formation of different types of carbon over Ni catalyst. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2907–2917, 2014
      PubDate: 2014-05-13T16:21:40.164809-05:
      DOI: 10.1002/aic.14487
       
  • Kinetic study of ethyl octyl ether formation from ethanol and 1-octanol on
           Amberlyst 70
    • Authors: Jordi Guilera; Roger Bringué, Eliana Ramírez, Carles Fité, Javier Tejero
      Pages: 2918 - 2928
      Abstract: An option to introduce bioethanol to diesel, improving at the same time its fuel quality, is by adding ethyl octyl ether (EOE). It can be obtained successfully by the dehydration reaction between ethanol and 1-octanol over acidic ion-exchange resins. In the present work, the kinetic study of EOE synthesis on Amberlyst 70 in the liquid phase is performed in a 20-cm3 fixed-bed reactor and in a 100-cm3 batch reactor at 423–463 K and 2.5 MPa. EOE synthesis takes place together with diethyl ether (DEE) formation as main side reaction. A mechanistic kinetic model in terms of component activities is proposed for EOE synthesis (Ea=105 ± 4 kJ/mol) and for DEE formation (Ea =100 ± 5 kJ/mol). Reaction rates were highly inhibited by the adsorption of the formed water on Amberlyst 70. The inhibitor effect of water is well represented as a competitive adsorption with alcohols reactants on the catalysts surface. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2918–2928, 2014
      PubDate: 2014-05-22T10:10:35.947853-05:
      DOI: 10.1002/aic.14497
       
  • Gas–liquid mass-transfer properties in CO2 absorption system with
           ionic liquids
    • Authors: Xin Zhang; Di Bao, Ying Huang, Haifeng Dong, Xiangping Zhang, Suojiang Zhang
      First page: 2929
      Abstract: The deficiency of mass-transfer properties in ionic liquids (ILs) has become a bottleneck in developing the novel IL-based CO2 capture processes. In this study, the liquid-side mass-transfer coefficients (kL) were measured systematically in a stirred cell reactor by the decreasing pressure method at temperatures ranging from 303 to 323 K and over a wide range of IL concentrations from 0 to 100 wt %. Based on the data of kL, the kinetics of chemical absorption of CO2 with mixed solvents containing 30 wt % monoethanolamine (MEA) and 0–70 wt % ILs were investigated. The kL in IL systems is influenced not only by the viscosity but also the molecular structures of ILs. The enhancement factors and the reaction activation energy were quantified. Considering both the mass-transfer rates and the stability of IL in CO2 absorption system, the new IL-based system MEA + [bmim][NO3] + H2O is recommended. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-03T14:08:00.34796-05:0
      DOI: 10.1002/aic.14507
       
  • Controlling thickener underflow rheology using a temperature responsive
           flocculant
    • Authors: George V. Franks; John-Paul O'Shea, Elizaveta Forbes
      Pages: 2940 - 2948
      Abstract: Continuous solid–liquid separations with the temperature responsive flocculant poly (N-isopropylacrylamide) (PNIPAM) were conducted in a pilot-scale thickener for the first time, using fine quartz as the feed slurry. The performance in continuous operation was compared to batch sedimentation. The increase in sediment consolidation on cooling in batch sedimentation was less significant in the continuous operation due to kinetic limitations of the deeper sediment bed and shorter residence times in the pilot-scale thickener. The reduction in underflow rheology which results when using the temperature responsive polymer as flocculant is significant. Paste-like behavior results when underflow is discharged at 50°C, whereas low viscosity, near Newtonian behavior results when the underflow is discharged at 20°C. Compared to conventional polyacrylamide-based flocculants, PNIPAM produces higher concentration underflow but lower clarity overflow and most importantly, significantly reduced underflow rheology (viscosity and yield stress). Temperature responsive flocculants have significant potential to reduce underflow pumping energy and cost for mineral tailings. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2940–2948, 2014
      PubDate: 2014-04-19T23:35:44.85616-05:0
      DOI: 10.1002/aic.14469
       
  • Thermal coupling links to liquid-only transfer streams: A path for new
           dividing wall columns
    • Authors: Gautham Madenoor Ramapriya; Mohit Tawarmalani, Rakesh Agrawal
      Pages: 2949 - 2961
      Abstract: We propose new dividing wall columns (DWCs) that are equivalent to the fully thermally coupled (FTC) configurations. While our method can draw such configurations for any given n-component mixture (n ≥ 3), we discuss in detail the DWCs for ternary and quaternary feed mixtures. A special feature of all the new DWCs is that during operation, they allow independent control of the vapor flow rate in each partitioned zone of the DWC by means that are external to the column. Because of this feature, we believe that the new arrangements presented in this work will enable the FTC configuration to be successfully implemented and optimally operated as a DWC in an industrial setting for any number of components. Also, interesting column arrangements result when a new DWC drawn for an n-component mixture is adapted for the distillation of a mixture containing more than n components. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2949–2961, 2014
      PubDate: 2014-04-23T14:23:40.312978-05:
      DOI: 10.1002/aic.14468
       
  • Inclusive separation of acetophenone from petrochemical by-product with
           1-phenylethanol via noncovalent interactions
    • Authors: Kungang Chai; Hongbing Ji
      Pages: 2962 - 2975
      Abstract: Separation of the barely studied mixture of acetophenone and 1-phenylethanol, a typical by-product obtained by oil refinery plant, based on the preferential affinity of β-cyclodextrin (abbreviated as β-CD) for acetophenone is focused. To demonstrate the potential application of β-CD for separation of acetophenone from 1-phenylethanol, the noncovalent interactions of β-CD with acetophenone and 1-phenylethanol were compared from thermodynamic and conformational points of view. For the purpose of separation, a multicomponent coprecipitation technique has been established based on the selective noncovalent binding property of β-CD, which has been proved rigorously. Under the optimized conditions, the acetophenone/1-phenylethanol equimolar binary mixture can be separated with a separation factor>37. For the petrochemical by-product, which contains 74.93 wt % of acetophenone, 17.79 wt % of 1-phenylethanol, and other minor compounds, expanding the separation scale, content of acetophenone in complex can get 99.2%, and the separation efficiency of β-CD kept stable after recycling twice. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2962–2975, 2014
      PubDate: 2014-04-30T10:46:29.71613-05:0
      DOI: 10.1002/aic.14474
       
  • Comparative performance of philic and phobic oil-mist filters
    • Authors: Benjamin J. Mullins; Ryan Mead-Hunter, Renato N. Pitta, Gerhard Kasper, Wolfgang Heikamp
      Pages: 2976 - 2984
      Abstract: The evolution of pressure drop, drainage rate, saturation, and efficiency of combined philic, and phobic oil mist filters in real-time are examined. The experiments used four different filter configurations, with a combination of oleophobic and oleophilic fibrous filter media, and one oleophilic only reference. The effect of separating filter materials of differing wettability, with a mesh, was also explored. It was found that inclusion of a mesh between layers promoted increased drainage rates and resulted in a significantly lower pressure drop across the filter. The overall mass-based filtration efficiency was also slightly higher for the configurations containing the mesh. Conversely, re-entrainment of droplets from the rear face of the filter was only observed in filter configurations without the central mesh. Filters with oleophobic initial layers did not display a classical “depth filtration” pressure drop curve. The oleophobic media was found to possess lower steady-state saturation than oleophilic media. Additionally, the steady-state saturation of the oleophilic filter media, when placed at the rear of the filter, was lower when the central mesh was present. The saturation values were compared with recently published theory. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2976–2984, 2014
      PubDate: 2014-05-06T09:54:22.634991-05:
      DOI: 10.1002/aic.14479
       
  • Application of microbial enhanced oil recovery technology in water-based
           bitumen extraction from weathered oil sands
    • Authors: Mingshan Ding; Yan Zhang, Juan Liu, Weihong Jia, Bin Hu, Sili Ren
      Pages: 2985 - 2993
      Abstract: When using the water-based extraction processes (WBEPs) to recover bitumen from the weathered oil sands, very low bitumen recovery arisen from the poor liberation of bitumen from sand grains is always obtained. Application of microbial enhanced oil recovery (MEOR) technology in WBEPs to solve the poor processability of the weathered ore was proposed. It was found that processability of the microbial-treated weathered ore was greatly improved. The improved processability was attributed to the biosurfactants production in the culture solution, alteration of the solids wettability, degradation of the asphaltene component, and the decrease of the bitumen viscosity, which collectively contributed to the bitumen liberation from the surface of sand grains. Although it still has many issues to be solved for an industrial application of the MEOR technology in oil sands separation, it is believed that the findings in this work promote the solution to the poor processability of the weathered ore. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2985–2993, 2014
      PubDate: 2014-05-08T09:57:44.96071-05:0
      DOI: 10.1002/aic.14483
       
  • Extractive distillation with the mixture of ionic liquid and solid
           inorganic salt as entrainers
    • Authors: Zhigang Lei; Xiaomin Xi, Chengna Dai, Jiqin Zhu, Biaohua Chen
      Pages: 2994 - 3004
      Abstract: The use of the mixture of ionic liquid (IL) and solid inorganic salt in place of the single IL as entrainers for extractive distillation, which integrates the advantages of a liquid solvent, that is, IL (easy operation and nonvolatility) and a solid salt (high separation ability) has been proposed in this work. The vapor–liquid equilibrium experiments indicated that the combination of [EMIM]+[Ac]− and KAc is the most promising for the separation of ethanol and water among all of the entrainers investigated. Based on the thermodynamic study, the conceptual process design was developed to evaluate the competitiveness of the suggested entrainers for the separation of ethanol and water. It was determined that the overall heat duty on reboilers in the extractive distillation process using the new mixed entrainers decreases 19.04% compared with the benchmark entrainer [EMIM]+[Ac]−. Moreover, the density functional theory and COSMO-RS model were used to achieve theoretical insights at the molecular level. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2994–3004, 2014
      PubDate: 2014-05-09T14:23:49.60562-05:0
      DOI: 10.1002/aic.14478
       
  • High performance materials based on a self-assembled multiple-percolated
           ternary blend
    • Authors: Sepehr Ravati; Christine Beaulieu, Ali M. Zolali, Basil D. Favis
      Pages: 3005 - 3012
      Abstract: In this study, it will be shown that morphologically tailored tricontinuous ternary blends, comprising polybutylene succinate (PBS), polylactic acid (PLA), and poly (butylene adipate-co-terephthalate)(PBAT), can generate new materials with excellent properties. Detailed morphological analysis is used to establish that all three phases in the ternary 33%PBS/33%PLA/33%PBAT blend morphology are highly continuous with a phase structure dominated by complete wetting dynamics. PBS is shown to situate itself between PLA and PBAT. This melt processed, self-assembled, multiple percolated, blend possesses a high elongation at break (567%), high Young's modulus (1130 MPa), high impact strength (271 J/m), and a storage modulus about 50% higher than pure PBS at room temperature. None of the neat materials demonstrate this combination of high properties and the synergy derives from the tricontinuous structure of the system. The ternary nature of the blend allows for a modulation of the crystallinity behavior as examined by differential scanning calorimeter and X-ray Diffraction. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3005–3012, 2014
      PubDate: 2014-06-02T16:04:09.649225-05:
      DOI: 10.1002/aic.14495
       
  • Multiphase dynamic flash simulations using entropy maximization and
           application to compressible flow with phase change
    • Authors: Lu Qiu; Yue Wang, Rolf D. Reitz
      First page: 3013
      Abstract: A UVn flash solver using a direct entropy maximization principle for phase splitting and Gibbs free energy minimization for phase stability is developed. The solver searches for the global stable state in a rigorous and thermodynamically consistent way. The solver is demonstrated to be robust and efficient to handle multiphase flash, even in the vicinity of phase boundaries. Dynamic flash computations and gas dynamics simulations of shock waves are considered for pure ethylene and for binary ethylene-nitrogen mixtures. The simulations show significantly different shock wave characteristics when phase separation is considered due to intensive energy exchange, compared to the frozen flow limiting single-phase solution. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-16T16:22:32.355883-05:
      DOI: 10.1002/aic.14519
       
  • Spray impact resistance of a superhydrophobic nanocomposite coating
    • Authors: Alexander Davis; Yong Han Yeong, Adam Steele, Eric Loth, Ilker S. Bayer
      Pages: 3025 - 3032
      Abstract: The performance of a polyurethane/organoclay superhydrophobic nanocomposite modified with perfluoroalkyl methacrylic copolymer in the presence of a high-pressure air-water spray which mimics an icing cloud impact is investigated in this study. To quantify the average velocites of droplets impacting the superhydrophobic samples, a computational study was performed. Such a study is important to understand the interaction between the jet and surface. Impacting velocities for three different testing conditions were estimated to be 14.5, 4.5, and 3.4 m/s. Liquid saturation did not occur immediately, but over time, the high mass flow rate of water led to antiwetting performance degradation. Upon evaporation, contact angle returned to pretest values, indicating little mechanical erosion. This was consistent with scanning electron microscopy which showed that the nano and microstructure was preserved, and with energy-dispersive X-ray spectroscopy, which showed no surface chemistry change after testing. However, sliding angle showed stronger degradation, especially at higher impact velocities. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3025–3032, 2014
      PubDate: 2014-04-08T15:59:51.807415-05:
      DOI: 10.1002/aic.14457
       
  • Experimental study of flow regimes in three-dimensional confined impinging
           jets reactor
    • Authors: Wei-Feng Li; Ke-Jiang Du, Guang-Suo Yu, Hai-Feng Liu, Fu-Chen Wang
      Pages: 3033 - 3045
      Abstract: Dynamic behaviors in a three-dimensional confined impinging jets reactor (CIJR) were experimentally studied by a flow visualization technique at 100 ≤ Re ≤ 2000 and 2 ≤ D/d ≤ 12 (where D is the reactor diameter and d is the nozzle diameter). The effects of inlet Reynolds numbers (Re) and geometry configurations of the CIJR on the flow regimes have been investigated by a particle image velocimetry and a high-speed camera. Results show that with the increasing Re, a segregated flow regime, a radial deflective oscillation, an axial oscillation and a vortex shedding regime emerge in turns in CIJR. A map of parameter space formed by the inlet Reynolds number (Re) and the normalized reactor diameter (D/d) has been presented. The effects of jet instability and confined boundary of the chamber on the flow regimes and their transition are also investigated and discussed. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3033–3045, 2014
      PubDate: 2014-04-08T16:35:48.142706-05:
      DOI: 10.1002/aic.14459
       
  • A comparison between numerical predictions and theoretical and
           experimental results for laminar core-annular flow
    • Authors: Jeroen C. Beerens; Gijs Ooms, Mathieu J. B. M. Pourquie, Jerry Westerweel
      Pages: 3046 - 3056
      Abstract: A numerical study, using the volume-of-fluid method, has been made of vertical (upward) laminar core-annular flow: the flow of a high-viscosity liquid core surrounded by a laminar low-viscosity liquid annular layer through a vertical pipe. The numerical results are compared with theoretical results from linear stability calculations and with experimental data. The comparison is good and the general conclusion of our study is that it is very well possible to simulate laminar core-annular flow in a pipe using the volume-of-fluid method. © 2014 The
      Authors . AIChE Journal, published by Wiley on behalf of the AIChE. AIChE J, 60: 3046–3056, 2014
      PubDate: 2014-04-23T14:02:09.608043-05:
      DOI: 10.1002/aic.14463
       
  • Modeling of cavern formation in yield stress fluids in stirred tanks
    • Authors: Qi Xiao; Ning Yang, Jiahua Zhu, Liejin Guo
      Pages: 3057 - 3070
      Abstract: Prediction of cavern formation in yield stress fluids in stirred tanks is of great importance for optimization. A new torus model is developed and then validated by experimental data and computational fluid dynamics simulation. Unlike existing mathematical models, the new torus model assumes that the circular center of the torus should not be outside the impeller swept region as the Reynolds number (Re) increases. Hence the cavern boundary is shaped like an apple torus rather than a horn torus. The new model also considers the cavern-vessel interactions. At relatively high Re, the new model predicts cavern shape and size better than other models. It correctly captures the cavern outline at various Re, which verified the assumption about torus center. The new model is then used to identify the influence of rheological parameters on cavern formation, and further extended to the cavern prediction of the dual-impeller system. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3057–3070, 2014
      PubDate: 2014-04-25T09:03:57.134385-05:
      DOI: 10.1002/aic.14470
       
  • Drop mass transfer in a microfluidic chip compared to a centrifugal
           contactor
    • Authors: Martin B. Nemer; Christine C. Roberts, Lindsey G. Hughes, Nicholas B. Wyatt, Carlton F. Brooks, Rekha Rao
      First page: 3071
      Abstract: A model system was developed for enabling a multiscale understanding of centrifugal-contactor liquid–liquid extraction. The system consisted of Nd(III) + xylenol orange in the aqueous phase buffered to pH = 5.5 by KHP, and dodecane + thenoyltrifluroroacetone (HTTA) + tributyphosphate (TBP) in the organic phase. Diffusion constants were measured for neodymium in both the organic and aqueous phases, and the Nd(III) partition coefficients were measured at various HTTA and TBP concentrations. A microfluidic channel was used as a high-shear model environment to observe mass transfer on a droplet scale with xylenol orange as the aqueous-phase metal indicator; mass-transfer rates were measured quantitatively in both diffusion and reaction limited regimes on the droplet scale. The microfluidic results were comparable to observations made for the same system in a laboratory scale liquid–liquid centrifugal contactor, indicating that single drop microfluidic experiments can provide information on mass transfer in complicated flows and geometries. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-13T12:48:25.728792-05:
      DOI: 10.1002/aic.14510
       
  • Regime transition in viscous and pseudo viscous systems: A comparative
           study
    • Authors: Swapna Rabha; Markus Schubert, Uwe Hampel
      First page: 3079
      Abstract: A comprehensive quantitative study on the effect of liquid viscosity (1 ≤ µL ≤ 1149 mPa-s) on the local flow phenomena of the gas phase in a small diameter bubble column is performed using ultrafast electron beam X-ray tomography. The internal dynamic flow structure and the bubble size distribution have shows a dual role of the liquid viscosity on the hydrodynamics. Further, effect of solid concentration (Cs = 0.05, 0.20) on the local flow behavior of the gas phase is studied for the pseudo slurry viscosities similar to the liquid viscosities of the gas-liquid systems. The effects of liquid and pseudo slurry viscosity on the flow structure, bubble size distribution and gas phase distribution are compared. The bubble coalescence is significantly enhanced with the addition of particles as compared to the system without particles for apparently same viscosity. The superficial gas velocity at which transition occurs from homogeneous bubbly to slug flow regime is initiated by the addition of particles as compared to the particle free system for apparently same viscosity. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-13T11:32:06.161598-05:
      DOI: 10.1002/aic.14528
       
 
 
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