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  Subjects -> ENGINEERING (Total: 1962 journals)
    - CHEMICAL ENGINEERING (151 journals)
    - CIVIL ENGINEERING (149 journals)
    - ELECTRICAL ENGINEERING (82 journals)
    - ENGINEERING (1119 journals)
    - HYDRAULIC ENGINEERING (45 journals)
    - INDUSTRIAL ENGINEERING (52 journals)
    - MECHANICAL ENGINEERING (74 journals)

ENGINEERING (1119 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: 21)
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: 4)
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: 5)
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]
  • Extractive Distillation with Ionic Liquids: A Review
    • Authors: Zhigang Lei; Chengna Dai, Jiqin Zhu, Biaohua Chen
      Pages: n/a - n/a
      Abstract: Extractive distillation is commonly used for the separation of azeotropic or close-boiling mixtures in the chemical industry. During the past decade, the use of ionic liquids (ILs) as entrainers has received considerable attention due to their unique advantages when applied in extractive distillation. This work is devoted to providing an easy-to-read and comprehensive review on the recent progress made by chemical engineers, focusing on the issues of predictive thermodynamic models, structure-property relations, separation mechanisms, and process simulation and optimization. This review spans from the molecular level to the industrial scale, to provide a theoretical insight into the molecular interactions between ILs and the components to be separated. Moreover, a comprehensive database on the vapor-liquid equilibria (VLE) and activity coefficients at infinite dilution concerning ILs is provided as Supporting Information. Concluding remarks are made on the unsolved scientific issues with respect to this promising special distillation technology. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-24T09:02:12.988406-05:
      DOI: 10.1002/aic.14537
  • An Approach to Mechanistic Event Recognition applied on monitoring organic
           matter depletion in SBRs
    • Authors: M. N. Cruz Bournazou; T. Barz, S. Junne, H. Arellano-Garcia, C. Kravaris, P. Neubauer
      Pages: n/a - n/a
      Abstract: A fundamental practice in process engineering is monitoring the state dynamics of a system. Unfortunately, observability of some states is related to high costs, time, and efforts. The Mechanistic Event Recognition (MER) aims to detect an event (defined as a change of the system with specific significance to the operation of the process) that cannot be directly observed but has some predictable effect on the dynamics of the systems. MER attempts to apply Fault Diagnosis techniques using mechanistic “recognition” models to describe the process. A systematic method for building recognition models using Optimal Experimental Design tools is presented. As proof of concept, we applied the MER approach to detect organic matter depletion in SBRs, measuring only ammonia, dissolved oxygen, and nitroxides. The event, i.e. consumption of organic matter to a level below 50 gCOD/L, was successfully detected even though microbial activity is known to continue after organic matter depletion. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-23T06:16:24.91286-05:0
      DOI: 10.1002/aic.14536
  • Numerical investigation of monodisperse granular flow through an inclined
           rotating chute
    • Authors: S.S. Shirsath; J.T. Padding, T.W.J. Peeters, H.J.H. Clercx, J.A.M. Kuipers
      Pages: n/a - n/a
      Abstract: We validate a Discrete Element Model of spherical glass particles flowing down a rotating chute against high quality experimental data. The simulations are performed in a co-rotating frame of reference, taking into account Coriolis and centrifugal forces. In view of future extensions aimed at segregation studies of polydisperse granular flows, several validation steps are required. In particular, the influence of the interstitial gas, a sensitivity study of the collision parameters, and the effect of system rotation on particle flow is investigated. Shirsath et al. have provided the benchmark laboratory measurements of bed height and surface velocities of monodisperse granular flow down an inclined rotating chute. With a proper choice of the friction coefficients the simulations show very good agreement with our experimental results. The effect of interstitial gas on the flow behavior is found to be relatively small for 3 mm granular particles. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-20T23:52:46.676114-05:
      DOI: 10.1002/aic.14535
  • Hydrodynamics and reactor performance evaluation of a high flux gas-solids
           circulating fluidized bed downer: Experimental study
    • Authors: Chengxiu Wang; Shahzad Barghi, Jesse Zhu
      Pages: n/a - n/a
      Abstract: Reactor performance of a high flux circulating fluidized bed (CFB) downer is studied under superficial gas velocities of 3-7 m/s with solids circulation rate up to 300 kg/m2s using ozone decomposition reaction. Results show that the reactant conversion in the downer is closely related to the hydrodynamics, with solids holdup being the most influential parameter on ozone decomposition. High degree of conversion is achieved at the downer entrance region due to strong gas-solids interaction as well as higher solids holdup and reactant concentration. Ozone conversion increases with the increase of solids circulation rate and/or the decrease of superficial gas velocity. Overall conversion in the CFB downer is less than but very close to that in an ideal plug flow reactor indicating a good reactor performance in the downer because of the nearly “ideal” hydrodynamics in downer reactors. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-20T23:52:04.795278-05:
      DOI: 10.1002/aic.14534
  • Rapid and large-scale separation of magnetic nanoparticles by low-field
           permanent magnet with gas assistance
    • Authors: Wensong Li; Liangrong Yang, Xiaopei Li, Zhini Liu, Fuchun Wang, Na Sui, Chuanxu Xiao, Huizhou Liu
      Pages: n/a - n/a
      Abstract: Bubbles can be used to greatly improve the speed of magnetic separation and overcome the limitation of magnetic force on the capture distance, making low-field magnetic separation highly efficient and easily scalable. This novel method leads to the development of a medium-free continuous gas-assisted magnetic separator on small pilot scale using low-field permanent magnet. This separator is demonstrated highly efficient for recovery of proteins-loaded magnetic nanoparticles from large volume bio-suspension. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-20T23:51:42.422824-05:
      DOI: 10.1002/aic.14533
  • Process data analytics in the era of big data
    • Authors: S. Joe Qin
      Pages: n/a - n/a
      PubDate: 2014-06-20T06:31:59.526711-05:
      DOI: 10.1002/aic.14523
  • Durable superoleophobic fabric surfaces with counterintuitive
           superwettability for polar solvents
    • Authors: Shuaijun Pan; Rui Guo, Weijian Xu
      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
  • Mass transfer enhancement by a reversible chemical reaction across the
           interface of a bubble rising under Stokes flow
    • Authors: Franck Pigeonneau; Marion Perrodin, Eric Climent
      Abstract: Mass transfer around a bubble rising in a liquid under Stokes regime is investigated when a reversible chemical reaction, A ⇄ B, is taken into account. Four dimensionless parameters control the interfacial transfer rate: the Péclet and Damköhler numbers, the ratio of the diffusion coefficient of both species and the reaction equilibrium constant. The mass transfer equations are solved numerically with a finite element technique. A boundary layer approach is also proposed and solved with a coupled technique of finite difference and Chebyshev-spectral method. The equilibrium constant and the ratio of diffusion coefficients have a strong influence on the coupling between the chemical reaction and mass transfer leading to an increase of the Sherwood number. The interaction between the chemical reaction and advection is clearly established by the simulations. Conditions corresponding to Péclet number larger than the Damköhler number reduces the effect of the chemical reaction. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-18T19:04:29.051011-05:
      DOI: 10.1002/aic.14520
  • MOF-derived porous carbon for adsorptive desulfurization
    • Authors: Yawei Shi; Xiangwen Zhang, Li Wang, Guozhu Liu
      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
  • Ionic liquid recovery alternatives in Ionic Liquid-based Three Phase
           Partitioning (ILTPP)
    • Authors: Enrique Alvarez-Guerra; Sónia P. M. Ventura, João A.P. Coutinho, Angel Irabien
      Pages: n/a - n/a
      Abstract: Ionic Liquid-based Three Phase Partitioning (ILTPP) is a promising technique to recover high-added value proteins at the liquid-liquid interface. Its economic and environmental performance highly depends on the net ionic liquid consumption. This work studies alternatives to maximize the fraction of ionic liquid that can be recycled. It is demonstrated that the addition of extra salt, previously proposed in literature, has a very limited effect on ionic liquid recovery for relatively high protein concentrations in the feed stream, and that it may even lead to an increase of the ionic liquid losses under certain conditions. However, small additions of salt are shown to be effective and profitable from an economic point of view. Vacuum evaporation is shown to allow for the complete ionic liquid and salt recovery reinforcing the sustainability and viability of ILTPP processes. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-17T03:12:39.150029-05:
      DOI: 10.1002/aic.14530
  • Critical isotherms from virial series using asymptotically consistent
    • Authors: Nathaniel S. Barlow; Andrew J. Schultz, Steven J. Weinstein, David A. Kofke
      Pages: n/a - n/a
      Abstract: We consider the low-density equation of state of a fluid along its critical isotherm. An asymptotically consistent approximant is formed having the correct leading-order scaling behavior near the vapor-liquid critical point, while retaining the correct low-density behavior as expressed by the virial equation of state. The formulation is demonstrated for the Lennard-Jones fluid, and models for helium, water, and n-alkanes. The ability of the approximant to augment virial-series predictions of critical properties is explored, both in conjunction with and in the absence of critical-property data obtained by other means. Given estimates of the critical point from molecular simulation or experiment, the approximant can refine the critical pressure or density by ensuring that the critical isotherm remains well-behaved from low density to the critical region. Alternatively, when applied in the absence of other data, the approximant remedies a consistent underestimation of the critical density when computed from the virial series alone. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-17T01:25:29.613385-05:
      DOI: 10.1002/aic.14531
  • On the tuning of predictive controllers: Impact of disturbances,
           constraints and feedback structure
    • Authors: Benjamin P. Omell; Donald J. Chmielewski
      Pages: n/a - n/a
      Abstract: This work investigates the impact of problem formulation modifications on predictive controller tuning. First, the proposed tuning method is shown to adapt to disturbance characteristic changes and thus takes full economic advantage of the scenario. The second topic concerns point-wise-in-time constraints and the impact of constraint infeasibility. Specifically, we shift the tuning question from selection of non-intuitive weighting matrix parameters to that of a few key parameters and results in a rather intuitive trade-off between expected profit and expected constraint violations. Finally, we show that simple modifications will allow for the consideration of various feedback structures, including computational delay and partial state information. The overall conclusions of the work are that the results of the automated algorithm will help build an intuitive understating of the dynamics of the process and ultimately result in a higher level trade-off between profit and constraint observance. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-17T00:13:12.783609-05:
      DOI: 10.1002/aic.14529
  • Kinetics of CO2 absorption into a novel 1-Diethylamino-2-propanol solvent
           using stopped-flow technique
    • Authors: Helei Liu; Zhiwu Liang, Teerawat Sema, Wichitpan Rongwong, Chen Li, Yanqing Na, Raphael Idem, Paitoon Tontiwachwuthikul
      Pages: n/a - n/a
      Abstract: In this work, a stopped-flow apparatus was used to measure the kinetics of CO2 absorption into aqueous solution of 1-diethylamino-2-propanol (1DEA2P) in terms of observed pseudo-first-order rate constant (k0) and second order reaction rate constant (k2). The experiments were conducted over a 1DEA2P concentration range of 120-751 mol/m3, and a temperature range of 298-313 K. Since 1DEA2P is a tertiary amine, the base catalyzed hydration mechanism was then applied to correlate the experimental CO2 absorption rate constants obtained from stopped-flow apparatus. In addition, the pKa of 1DEA2P was experimentally measured over a temperature range of 278-333 K. The Brønsted relationship between reaction rate constant (obtained from stopped-flow apparatus) and pKa was then studied. The results showed that the correlation based on the Brønsted relationship performed very well for predicting the absorption rate constant with an AAD of 5.2%, which is in an acceptable range of less than 10%. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-17T00:03:19.903174-05:
      DOI: 10.1002/aic.14532
  • Novel design and performance of a medical oxygen concentrator using a
           rapid pressure swing adsorption concept
    • Authors: Vemula Rama Rao; Mayuresh V. Kothare, Shivaji Sircar
      Abstract: A novel design of a compact rapid pressure swing adsorption (RPSA) system consisting of a single adsorber enclosed inside a product storage tank is proposed for application as a medical oxygen concentrator (MOC). A self-contained test unit for the process is constructed which is capable of directly and continuously producing 1 – 3 sl/m of 90 % O2 from compressed air. Pelletized LiLSX zeolite is used as the air separation adsorbent. Steady state process performance data [bed size factor (BSF) and O2 recovery (R) as functions of total cycle time (tc)], as well as transient, cyclic, adsorber pressure and temperature profiles are presented. A four-step Skarstrom- like PSA cycle was employed. Two options for column pressurization, (a) using compressed feed air co-currently or, (b) using a part of the oxygen-enriched product gas counter-currently were evaluated. Option (b) exhibited superior performance. The optimum total cycle time for option (b) was 5 - 6 seconds where the BSF was lowest (˜ 45 kgs/TPD O2) and the corresponding R was ˜ 29.3 %. These numbers indicate that the adsorbent inventory of a MOC can be potentially reduced by a factor of three while offering a ˜ 10 - 20 % higher O2 recovery compared to a typical commercial unit. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-16T16:31:43.759152-05:
      DOI: 10.1002/aic.14518
  • Multiphase dynamic flash simulations using entropy maximization and
           application to compressible flow with phase change
    • Authors: Lu Qiu; Yue Wang, Rolf D. Reitz
      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
  • process flowsheet synthesis: Reaching targets for idealized coal
    • Authors: James Alistair Fox; Diane Hildebrandt, David Glasser, Bilal Batel, Brendon Hausberger
      Abstract: The gasification of coal is a process that has been commonly used to produce a mixture of gases containing primarily carbon dioxide and hydrogen, called syngas. This syngas is used as an intermediate in the production of many chemicals such as ammonia, synthetic hydrocarbons and methanol (to name a few). Coal gasification has a reputation for being “dirty” in terms of its emissions in comparison with other syngas creation technologies, such as methane reforming. However, there is remarkably little information on what the “best case” for coal gasification could actually be and how existing process perform relative to that “best case". The goal of this paper is to formulate a preliminary and conceptual flowsheet for the gasification process; this flowsheet is not intended to be a finalized design or a definitive solution. It is intended to illustrate the method of setting and achieving design objectives and provide a basis of comparison for either new or existing processes. Thermodynamics can be used to describe any process, or system of processes. Of particular interest are the properties of enthalpy and Gibbs free energy. By using these two thermodynamic properties together as vectors on a diagram of free energy (ΔG) against enthalpy (ΔH), it becomes possible to develop better process flow sheets that combine the thermodynamics of chemical reactions and the dynamics of physical operations on a single diagram. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-16T16:02:44.507959-05:
      DOI: 10.1002/aic.14521
  • Drop mass transfer in a microfluidic chip compared to a centrifugal
    • Authors: Martin B. Nemer; Christine C. Roberts, Lindsey G. Hughes, Nicholas B. Wyatt, Carlton F. Brooks, Rekha Rao
      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
    • Authors: Swapna Rabha; Markus Schubert, Uwe Hampel
      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
  • Kinetic parameter estimation of HDPE slurry process from molecular weight
           distribution: Estimability analysis and multistep methodology
    • Authors: Chen Zhang; Zhijiang Shao, Xi Chen, Zhen Yao, Xueping Gu, Lorenz T. Biegler
      Abstract: This study addresses kinetic parameter estimation for a high-density polyethylene (HDPE) slurry process based on fitting molecular weight distributions (MWDs). From the process model we conduct an estimability analysis by assessing the relative sensitivity between output variables and kinetic parameters as well as confidence intervals. This determines which parameters can be estimated. On the other hand, a major challenge remains with the solution of an ill-conditioned parameter estimation problem with MWD as the output variable. To overcome the convergence difficulties with the associated problem, we develop a novel multistep methodology where we first obtain MWD parameters by matching to data and then estimate kinetic parameters by matching to the regressed MWD parameters. Computational results and eigenvalue analysis shows this multistep methodology separates an ill-conditioned problem into two well-conditioned subproblems. Moreover, we consider simulation-based and industrial HDPE case studies. These results demonstrate the applicability, potential, and efficiency of this solution procedure. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-13T10:09:15.727662-05:
      DOI: 10.1002/aic.14527
  • 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
  • Liquid-phase Hydrogenation of Cinnamaldehyde over Cu-Au/SiO2 Catalysts
    • Authors: Xiang Yuan; Jianwei Zheng, Qian Zhang, Shuirong Li, Yanhui Yang, Jinlong Gong
      Abstract: This paper describes the synthesis, characterization, and application of silica-supported Cu-Au bimetallic catalysts in selective hydrogenation of cinnamaldehyde (CALD). The results showed that Cu-Au/SiO2 bimetallic catalysts are superior to monometallic Cu/SiO2 and Au/SiO2 catalysts under identical conditions. Adding a small amount of gold (6Cu-1.4Au/SiO2 catalyst) afforded 8-fold higher catalytic reaction rate compared to Cu/SiO2 along with the high selectivity (53%, at 55% of conversion) towards cinnamyl alcohol (CALC). Characterization techniques such as X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), ultraviolet-visible spectroscopy (UV-Vis), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectra of chemisorbed CO, and X-ray photoelectron spectroscopy (XPS) were employed to understand the origin of the catalytic activity. A key genesis of the high activity of the Cu-Au/SiO2 catalyst was ascribed to the synergistic effect of Cu and Au species: the Au sites were responsible for the dissociative activation of H2 molecules, and Cu0 and Cu+ sites contributed to the adsorption-activation of C=C and C=O bond, respectively. A combined tuning of particle dispersion and its surface electronic structure was shown as a consequence of the formation of Au-Cu alloy nanoparticles, which led to the significantly enhanced synergy. A plausible reaction pathway was proposed based on our results and the literature. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-12T20:39:43.939916-05:
      DOI: 10.1002/aic.14522
  • Optimal design of large-scale chemical processes under uncertainty: A
           ranking-based approach
    • Authors: Sami S. Bahakim; Shabnam Rasoulian, Luis A. Ricardez-Sandoval
      Abstract: An approach for the optimal design of chemical processes in the presence of uncertainty was presented. The key idea in this work is to approximate the process constraint functions and model outputs using Power Series Expansions (PSE)-based functions. The PSE functions are used to efficiently identify the variability in the process constraint functions and model outputs due to multiple realizations in the uncertain parameters using Monte Carlo (MC) sampling methods. A ranking-based approach is adopted here where the user can assign priorities or probabilities of satisfaction for the different process constraints and model outputs considered in the analysis. The methodology was tested on a reactor–heat exchanger system and the Tennessee Eastman process. The results show that the present method is computationally attractive since the optimal process design is accomplished in shorter computational times when compared to the use of the MC method applied to the full plant model. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-11T16:15:38.394145-05:
      DOI: 10.1002/aic.14515
  • Optimal interplant water networks for industrial zones: Addressing
           interconnectivity options through pipeline merging
    • Authors: Sabla Y. Alnouri; Patrick Linke, Mahmoud El-Halwagi
      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
  • Selection of control configurations for economic model predictive control
    • Authors: Matthew Ellis; Panagiotis D. Christofides
      Abstract: Economic model predictive control (EMPC) is a feedback control method that dictates a potentially dynamic (time-varying) operating policy to optimize the process economics. The objective function used in the EMPC system may be a general nonlinear function that describes the process/system economics. As this function is not derived on the sole basis of classical control considerations (stabilization, tracking, and optimal control action calculation) but rather on the basis of economics, selecting the appropriate control configuration, and quantifying the influence of a given input on an economic cost is an important task for the proper design and computational efficiency of an EMPC scheme. Owing to these considerations, an input selection methodology for EMPC is proposed which utilizes the relative degree and the sensitivity of the economic cost with respect to an input to identify and select stabilizing manipulated inputs with the most dynamic and steady-state influence on the economic cost function to be assigned to EMPC. Other considerations for input selection for EMPC are also discussed and integrated into a proposed input selection methodology for EMPC. The control configuration selection method for EMPC is demonstrated using a chemical process example. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-09T12:03:53.126585-05:
      DOI: 10.1002/aic.14514
  • Global optimization for sustainable design and synthesis of algae
           processing network for CO2 mitigation and biofuel production using life
           cycle optimization
    • Authors: Jian Gong; Fengqi You
      Abstract: Global optimization for sustainable design and synthesis of a large-scale algae processing network under economic and environmental criteria is addressed. An algae processing network superstructure including 7800 processing routes is proposed. Based on the superstructure, a multiobjective mixed-integer nonlinear programming (MINLP) model is developed to simultaneously optimize the unit cost and the unit global warming potential (GWP). To efficiently solve the nonconvex MINLP model with separable concave terms and mixed-integer fractional terms in the objective functions, a global optimization strategy that integrates a branch-and-refine algorithm based on successive piecewise linear approximations is proposed and an exact parametric algorithm based on Newton's method. Two Pareto-optimal curves are obtained for biofuel production and biological carbon sequestration, respectively. The unit annual biofuel production cost ranges from $7.02/gasoline gallon equivalent (GGE) to $9.71/GGE, corresponding to unit GWP's of 26.491 to 16.52 kg CO2-eq/GGE, respectively. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-09T11:41:41.001215-05:
      DOI: 10.1002/aic.14504
  • Fair profit allocation in supply chain optimization with transfer price
           and revenue sharing: MINLP model and algorithm for cellulosic biofuel
           supply chains
    • Authors: Dajun Yue; Fengqi You
      Abstract: A mixed-integer nonlinear programming (MINLP) formulation to simultaneously optimize operational decisions as well as profit allocation mechanisms in supply chain optimization, namely material transfer prices and revenue share policies among the supply chain participants is proposed. The case of cellulosic bioethanol supply chains is specifically considered and the game-theory Nash bargaining solution approach is employed to achieve fair allocation of profit among the collection facilities, biorefineries, and distribution centers. The structural advantages of certain supply chain participants can be taken into account by specifying different values of the negotiation-power indicators in the generalized Nash-type objective function. A solution strategy based on a logarithm transformation and a branch-and-refine algorithm for efficient global optimization of the resulting nonconvex MINLP problem is proposed. To demonstrate the application of the proposed framework, an illustrative example and a state-wide county-level case study on the optimization of a potential cellulosic bioethanol supply chain in Illinois are presented. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-09T11:41:31.747333-05:
      DOI: 10.1002/aic.14511
  • Discrete element reduced-order modeling of dynamic particulate systems
    • Authors: Amanda Rogers; Marianthi G. Ierapetritou
      Abstract: One of the key technical challenges associated with modeling particulate processes is the ongoing need to develop efficient and accurate predictive models. Often the models that best represent solids handling processes, like discrete element method (DEM) models, are computationally expensive to evaluate. In this work, a reduced-order modeling (ROM) methodology is proposed that can represent distributed parameter information, like particle velocity profiles, obtained from high-fidelity (DEM) simulations in a more computationally efficient fashion. The proposed methodology uses principal component analysis (PCA) to reduce the dimensionality of the distributed parameter information, and response surface modeling to map the distributed parameter data to process operating parameters. This PCA-based ROM approach has been used to model velocity trajectories in a continuous convective mixer, to demonstrate its applicability for pharmaceutical process modeling. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-05T15:36:37.692167-05:
      DOI: 10.1002/aic.14505
  • Photocatalytic degradation of malic acid using a thin coated TiO2-film:
           Insights on the mechanism of photocatalysis
    • Authors: Vanessa Rodgher; Jesus Moreira, Hugo Lasa, Benito Serrano
      Abstract: Decontamination of opaque fluids using photocatalysts and near Ultraviolet (UV) irradiation involves major technical challenges. This study considers a thin TiO2 layer placed in a new Chemical Reactor Engineering Centre (CREC)-photoreactor cell. This new photoreactor cell is used for the photocatalytic degradation of malic and malonic acids, typical apple juice components. Conversion of organic species can only proceed through the “dark side” of the TiO2 layer, which is in direct contact with the fluid. Under the selected operating conditions both external mass-transfer limitations and photolysis are found to be negligible. Macroscopic radiation balance shows that 92% of near UV radiation is absorbed by the ‘back side” of the TiO2-film. Photocatalytic degradation experiments with 10, 20, 30, and 40 ppm malic acid initial concentrations, show that malonic acid is a main intermediate. Complete malic acid conversion occurs after 5–8 h of irradiation. Kinetic modeling of malic and malonic acid photodegradation with kinetic parameter estimation is performed using both an “in series” and an “in series-parallel” reaction networks. The “in series-parallel” reaction network displays better ability for predicting CO2 formation, showing maximum quantum yields of 14.2%. Given that in the CREC-photoreactor cell with a thin TiO2-film, photocatalysis can only proceed via the transfer of mobile “h+” sites from the irradiated side to the “dark side', this study demonstrates the significance of this step on the overall photocatalysis mechanism. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-05T15:31:56.267782-05:
      DOI: 10.1002/aic.14500
  • Improved magnetic particle tracking technique in dense gas fluidized beds
    • Authors: Kay A. Buist; Alex C. Gaag, Niels G. Deen, Johannes A. M. Kuipers
      Abstract: Noninvasive monitoring of multiphase flow is rapidly gaining increased interest. More specifically noninvasive particle tracking techniques have received a lot of attention in recent years to study dense granular flow. However, these techniques are usually quite expensive and require strict safety measures. An improved magnetic particle tracking (MPT) technique for dense granular flow will be presented in this article. The improvements of the analysis technique for MPT will be demonstrated and rigorously tested with a three-dimensional system and two-dimensional sensor system. The strengths and limitations of the MPT technique will also be reported. Finally, the results of the MPT are compared with data obtained from a combined particle image velocimetry and digital image analysis technique. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-04T14:06:30.925908-05:
      DOI: 10.1002/aic.14512
  • Integration of scheduling and control for batch processes using
           multi-parametric model predictive control
    • Authors: Jinjun Zhuge; Marianthi G. Ierapetritou
      Abstract: Integration of scheduling and control results in Mixed Integer Nonlinear Programming (MINLP) which is computationally expensive. The online implementation of integrated scheduling and control requires repetitively solving the resulting MINLP at each time interval. (Zhuge and Ierapetritou, Ind Eng Chem Res. 2012;51:8550–8565) To address the online computation burden, we incorporare multi-parametric Model Predictive Control (mp-MPC) in the integration of scheduling and control. The proposed methodology involves the development of an integrated model using continuous-time event-point formulation for the scheduling level and the derived constraints from explicit MPC for the control level. Results of case studies of batch processes prove that the proposed approach guarantees efficient computation and thus facilitates the online implementation. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-03T14:23:27.760744-05:
      DOI: 10.1002/aic.14509
  • 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
      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
  • A novel multiple linear multivariate NIR calibration model-based strategy
           for in-line monitoring of continuous mixing
    • Authors: Leonel Quiñones; Carlos Velazquez, Luis Obregon
      Abstract: The capability of near infra-red (NIR) spectroscopy to predict many different variables, such as concentration and humidity, has been demonstrated in many published works. Several of those articles have been in the subject of real time prediction of continuous operations. However, those demonstrations have been for narrow ranges of the variables, especially for powder concentration, which could present a nonlinear behavior of the NIR absorbance as a function of the entire range of concentration. This work developed a novel strategy to predict the entire range of powder concentration using multiple linear NIR calibration models. The root mean standard error of prediction and relative standard deviation (RSD) parameters were used to establish the number of the multiple linear calibration models; other statistical features were used to establish the correct prediction. It was found that a minimum number of linear partial least squares (PLS) calibration models were necessary to accurately predict the range from 0 to 100% w/w. This technique could also be used with other nonlinear behaviors. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-02T16:12:27.884136-05:
      DOI: 10.1002/aic.14498
  • Confirmation of predicted activity for factor XIa inhibitors from a
           virtual screening approach
    • Authors: Hang Li; Donald P. Visco, Nic D. Leipzig
      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
  • Insight into the intraparticle diffusion of residue oil components in
           catalysts during hydrodesulfurization reaction
    • Authors: Zhigang Wang; Sheng-Li Chen, Jianing Pei, Aicheng Chen, Junhui Zhang, Zhiming Xu, Jay B. Benziger
      Abstract: Well-defined and uniform pore structure catalysts were used to study the intraparticle diffusion of fractionated Saudi vacuum residue under hydrodesulfurization (HDS) reaction conditions. HDS rates of residue oil cuts with different molecular weights are determined as functions of pore size, temperature, and pressure in a trickle-bed reactor. Credible intrinsic and bulk diffusivities of organosulfur compounds in residue oil were obtained for the first time, from the apparent and intrinsic reaction kinetic constants. Intrinsic diffusivities ranged from 2 × 10−7 to 8 × 10−7 cm2/s for the residual oil molecules; diffusivity decreases with increasing molecular weight of the residual oil. The intrinsic diffusivity for molecular weights ∼1000 Daltons increases with pore size for pores 70 nm. The diffusivity dependences on pore size and molecular weight suggest that the onset of restricted diffusion occurs for ratios of molecular diameter to pore diameter of ∼0.04. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-06-02T16:05:51.775636-05:
      DOI: 10.1002/aic.14501
  • 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
  • Performance optimization of an electromembrane reactor for recycling and
           resource recovery of desulfurization residuals
    • Authors: Chenglei Yang; Ying Hu, Limei Cao, Ji Yang
      Pages: n/a - n/a
      Abstract: An environmentally friendly method for electrochemically regenerating alkali‐sorbent (NaOH) and recovering sulfur in the flue gas as H2SO4, while producing H2 as a clean energy source from flue gas desulfurization (FGD) residuals in an electromembrane reactor, was proposed in this article. To optimize and improve the performance, the optimal operating conditions were deduced from the numerical simulation and validated using experimental data. Under the optimized conditions, the current efficiencies of alkali‐sorbent regeneration and H2SO4 reached 84 and 87%, respectively, which is comparable to those obtained in the chlor‐alkali industry. Therefore, this method has the potential to be scaled up. If this technology is integrated into an existing FGD facility, the money‐consuming chemical process could be transferred into a renewable resource and clean energy conversion process. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-04-23T09:14:46.893012-05:
      DOI: 10.1002/aic.14466
  • Solubilities of small hydrocarbons, viscosities of diluted
           tetraalkylphosphonium bis(2,4,4‐trimethylpentyl) phosphinates
    • Authors: Xiangyang Liu; Waheed Afzal, Maogang He, John M. Prausnitz
      Pages: n/a - n/a
      Abstract: Tetraalkylphosphonium bis(2,4,4‐trimethylpentyl)phosphinates show large solubilities for methane, ethane, ethylene, and propane. In these ionic liquids, solubilities of ethane are larger than those of ethylene. Therefore, these ionic liquids may be useful solvents for separation of ethane and ethylene; because the vapor pressure of ethylene is higher than that of ethane, the relative volatility ethylene/ethane is enhanced. However, the viscosities of these ionic liquids are too high for an industrial process. Low‐viscosity 1‐butyl‐3‐H‐imidazolium acetate([BHMIM][AC]) is a suitable diluent for reducing the large viscosities of trihexyl tetradecylphosphonium bis(2,4,4‐trimethylpentyl) phosphinate ([P(14)666][TMPP]) and tetrabutylphosphonium bis(2,4,4‐trimethylpentyl) phosphinate ([P4444][TMPP]). Addition of 20 wt % [BHMIM][AC] gives a dramatic drop in the viscosities of these ionic liquids. Mixtures of [P(14)666][TMPP] or [P4444][TMPP] with 20 or 50 wt % [BHMIM][AC] show high solubilities for the four solutes when compared with those in other ionic liquids. In these mixtures, the solubility for ethane is higher than that for ethylene. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-04-18T17:52:43.663483-05:
      DOI: 10.1002/aic.14453
  • Chemical effect of hydrodynamic cavitation: Simulation and experimental
    • Authors: Mauro Capocelli; Marina Prisciandaro, Amedeo Lancia, Dino Musmarra
      Pages: n/a - n/a
      Abstract: This paper deals with the chemical effect of hydrodynamic cavitation (HC) in a Venturi reactor from both the theoretical and the experimental point of view. A mathematical model is presented in order to simulate the global production of hydroxyl radicals; it is based on a set of ordinary differential equations that account for the hydrodynamics, mass diffusion, heat exchange and chemical reactions inside the bubbles. Experimentally, the degradation of p‐nitrophenol (initial concentration 0.15 g dm‐3) has been conducted in a lab scale Venturi reactor at inlet pressure ranging from 0.2 to 0.6 MPa and has been used to estimate the hydroxyl radical production. The optimum configuration, suggested by numerical simulations, has been experimentally confirmed. Thanks to the empirical validation, this novel modeling approach can be considered as a theoretical tool to identify the best configuration of HC operating parameters. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-04-18T04:20:18.408443-05:
      DOI: 10.1002/aic.14472
  • Synthesis of augmented biofuel processes using solar energy
    • Authors: Dharik S. Mallapragada; Rakesh Agrawal, Mohit Tawarmalani
      Pages: n/a - n/a
      Abstract: A method for synthesizing augmented biofuel processes, which improve biomass carbon conversion to liquid fuel (ηcarbon) using supplemental solar energy as heat, H2, and electricity is presented. For a target ηcarbon, our method identifies augmented processes requiring the least solar energy input. A nonconvex mixed integer nonlinear programming model allowing for simultaneous mass, heat, and power integration, is built over a process superstructure and solved using global optimization tools. As a case study, biomass thermochemical conversion via gasification/Fischer–Tropsch synthesis and fast‐hydropyrolysis/hydrodeoxygenation (HDO) is considered. The optimal process configurations can be categorized either as standalone (ηcarbon ≤ 54%), augmented using solar heat (54% ≤ ηcarbon ≤ 74%), or augmented using solar heat and H2 (74 ≤ ηcarbon ≤ 95%). Importantly, the process H2 consumption is found to be close to the derived theoretical minimum values. To accommodate for the intermittency of solar heat/H2, we suggest processes that can operate at low and high ηcarbon. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-04-11T13:37:53.89569-05:0
      DOI: 10.1002/aic.14456
  • 2‐Dimensional Zeolites
    • Authors: Michael Tsapatsis
      Pages: n/a - n/a
      PubDate: 2014-04-11T05:56:01.001763-05:
      DOI: 10.1002/aic.14462
  • Physical characterization of eco‐friendly O/W emulsions developed
           through a strategy based on product engineering principles
    • Authors: Jenifer Santos; Luis A. Trujillo‐Cayado, Nuria Calero, José Muñoz
      Pages: n/a - n/a
      Abstract: Many traditional industrial products are being gradually replaced by environmental friendly alternatives. N,N‐Dimethyldecanamide and D‐limonene are solvents that fulfil the requirements to be considered green solvents and may find application in agrochemicals. This contribution deals with the study of emulsions formulated with a mixture of these solvents and an eco‐friendly emulsifier. The procedure followed for the development of these formulations was based on the application of product design principles. This led to the optimum homogenization rate and subsequently to the optimum ratio of solvents. The combination of different techniques (rheology, laser diffraction, confocal laser‐scanning microscopy, and multiple light scattering) was demonstrated to be a powerful tool to assist in the prediction of the emulsions destabilization process. Thus, we found that the optimum ratio of solvents was 75/25 (N,N‐dimethyldecanamide/D‐limonene) on account of the lack of coalescence and of a low creaming rate. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-04-08T16:35:45.540229-05:
      DOI: 10.1002/aic.14460
  • Dynamic real‐time optimization and control of a hybrid energy system
    • Authors: Milana Trifkovic; W. Alex Marvin, Prodromos Daoutidis, Mehdi Sheikhzadeh
      Pages: n/a - n/a
      Abstract: A proactive energy management strategy for a stand‐alone hybrid renewable energy system is presented. The study was motivated by the system built in Lambton College (Sarnia, Ontario, Canada) which includes photovoltaic arrays, wind turbine, battery, electrolyzers, hydrogen storage tanks, and fuel cells. The control architecture consists of two levels of hierarchy: (1) optimal predictive scheduling at the supervisory level and (2) local controllers for each of the system units. A “day‐ahead” approach is followed at the supervisory level and a bidirectional communication between the supervisory, proactive control, and the low‐level control layer is established. The proposed energy management strategy accounts for external (i.e., weather and demand) and internal disturbances. The efficacy of the proposed strategy is demonstrated through case studies. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-04-08T16:12:04.08158-05:0
      DOI: 10.1002/aic.14458
  • Refinery scheduling with varying crude: A deep belief network
           classification and multimodel approach
    • Authors: Xiaoyong Gao; Chao Shang, Yongheng Jiang, Dexian Huang, Tao Chen
      Pages: n/a - n/a
      Abstract: In model‐based refinery scheduling, the varying composition of the crude being refined is a major challenge, especially for those reaction processes. A classification based, multimodel approach is proposed to handle the frequently varying crude. The idea is to build a scheduling model for each type of feed crude, and the type can be determined using an online classifier. The recently emerged deep belief network is introduced to develop the classifier, which provides more accurate classification than the traditional neural network. The proposed method is demonstrated through modeling a fluidized catalytic cracking unit (the mostly affected by varying crude), and then the scheduling of a refinery that was carefully simulated to mimic the actual operation of a refinery in northern China. The results reveal that the multimodel approach is effective in handling varying crude. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-04-04T16:27:26.695992-05:
      DOI: 10.1002/aic.14455
  • Dynamics of droplets and mass transfer in a rotating packed bed
    • Authors: Zuo‐yi Yan; Cheng Lin, Qi Ruan
      Pages: n/a - n/a
      Abstract: To do further research on the mass‐transfer mechanism in rotating packed bed (RPB), dynamics of droplets in a RPB are studied by an analytical approach combined with a series of laboratory measurements. Based on the results of the fluid dynamics, mathematical models of mass‐transfer coefficient and mass‐transfer process in RPB are proposed, respectively. Mass‐transfer experiments in RPB are also carried out using ethanol–water solution. By comparison, the results of simulation agree well with that of the experiment, which demonstrate that both hydrodynamic model and mass‐transfer models can better describe the real conditions of RPB. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-04-04T15:51:32.641885-05:
      DOI: 10.1002/aic.14449
  • Intensification of fast exothermic reaction by gas agitation in a
           microchemical system
    • Authors: Jisong Zhang; Kai Wang, Xiyan Lin, Yangcheng Lu, Guangsheng Luo
      Pages: n/a - n/a
      Abstract: The Beckmann rearrangement of cyclohexanone oxime in oleum as a fast exothermic reaction model is carried out in an adiabatic multiphase microchemical system. A severe coalescene is observed due to the high viscosity of the rearrangement mixture, which decreases the reaction rate and selectivity. Gas agitation is introduced into the microsystem to enhance the reaction by reducing the coalescene and providing an evaporation space to carry away reaction heat. The effects of gas agitation on dispersion performance and mass‐transfer rate have been investigated. The acid droplets diameter ranges from about 44 to 20 µm, decreasing with the increase of the gas flow rate. The overall volume mass‐transfer coefficient in the microsystem ranges from 0.16 to 0.74 s−1, 1.5–3.8 times larger than that without gas agitation. The reaction performance is evaluated under different conditions and better conversion and selectivity are obtained. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-04-03T15:00:23.797131-05:
      DOI: 10.1002/aic.14450
  • Multiscale modeling for surface composition of spray‐dried
           two‐component powders
    • Authors: Jie Xiao; Xiao Dong Chen
      Pages: n/a - n/a
      Abstract: Spray drying is a primary process for manufacturing various powder products. One of the most important properties of powders is the ability to get wet. Surface chemical composition critically influences this property. Furthermore, surface composition also influences the efficiency of production as it affects the stickiness of the powder. This work is an attempt to analyze the surface compositions of spray‐dried two‐component powders produced under various conditions using an innovative multiscale modeling approach. A molecular‐level geometrical interpretation is seamlessly coupled with a continuum diffusion model. The predictions are compared with the measurements done on the protein–lactose system using X‐ray photoelectron spectroscopy. Sample calculations for the system have demonstrated that the new approach helps reveal surface formation mechanisms much better than that explained with the monoscale continuum approach. This work provides a good basis for a fruitful area of study toward surface composition‐focused powder quality control that will have a positive impact in industries. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-04-03T14:17:39.937933-05:
      DOI: 10.1002/aic.14452
  • Fate of a sessile droplet absorbed into a porous surface experiencing
           chemical degradation
    • Authors: Theresa Atkinson; Homayun K. Navaz, Albert Nowakowski, Krissy Kamensky, Ali Zand, Janice Jackson
      Pages: n/a - n/a
      Abstract: A general‐purpose multiphase and multicomponent computer model was developed for simulation of the spread, evaporation, and chemical reaction of sessile droplet(s) in porous substrates. In the model, chemical reactions were allowed in or between any of the liquid, gas, or solid phases present. The species mass and momentum conservation equations were solved on a finite difference mesh representing the domain. These equations were marched in time using the Runge–Kutta fourth‐order method. The model's function was studied via simulation of experiments, both those performed by the authors and found in the literature. These simulations demonstrated a quantitative match to the time history of product evolution and a similar spread of liquid reactants. The model may be particularly beneficial for predicting the extent of contamination and the possible threat outcomes of those chemical agents that are harmful when introduced into the environment. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-04-03T13:58:06.079694-05:
      DOI: 10.1002/aic.14454
  • Effects of foaming and antifoaming agents on the performance of a wet flue
           gas desulfurization pilot plant
    • Authors: Siqiang Qin; Brian B. Hansen, Søren Kiil
      First page: 2382
      Abstract: Foaming is a common phenomenon in industrial processes, including wet flue gas desulfurization (FGD) plants. A systemic investigation of the influence of two foaming agents, sodium dodecyl sulphate (SDS) and egg white albumin (protein), and two commercial antifoams on a wet FGD pilot plant operation has been carried out. Foaming caused by 0.03 g SDS/(L slurry) reduced the desulfurization degree from 84 to 74% and the solids and limestone concentrations of the slurry from 58 to 48 g/(L slurry) and from 1.4 to 1.0 g/(L slurry), respectively. These effects were attributed to the foaming transferring small particles to the foam layer present on top of the slurry in the holding tank. The addition of 0.03 g antifoams/(L slurry) to SDS foam eliminated the foam, but the desulfurization degree remained low. Potential mechanisms for the observed behavior are analyzed. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2382–2388, 2014
      PubDate: 2014-03-13T10:05:27.883158-05:
      DOI: 10.1002/aic.14428
  • In situ characterization of floc morphology by image analysis in a
           turbulent Taylor–Couette reactor
    • Authors: Mélody Vlieghe; Carole Coufort-Saudejaud, Christine Frances, Alain Liné
      First page: 2389
      Abstract: Flocculation of bentonite was performed in a turbulent Taylor–Couette reactor under various shear rates. Image processing enabled to determine various morphological characteristics of individual flocs. Not only their mean values but also their distributions were studied under various hydrodynamic conditions. Relevant properties were selected. The temporal evolution of radius of gyration and circularity distributions was monitored during the flocculation process. Although size and shape are obviously correlated, this article points out that their dependency to hydrodynamics is different, showing that flocs of similar sizes produced under different hydrodynamic conditions exhibit different shapes. The sizes are calibrated by the turbulence as the double radius of gyration is close to Kolmogorov microscale, whereas the circularity seems correlated to the rotation speed. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2389–2403, 2014
      PubDate: 2014-03-14T19:23:16.709932-05:
      DOI: 10.1002/aic.14431
  • Formulation of a physically motivated specific breakage rate parameter for
           ball milling via the discrete element method
    • Authors: Maxx Capece; Ecevit Bilgili, Rajesh N. Davé
      First page: 2404
      Abstract: A physically based specific breakage rate parameter of the population balance model for batch dry-milling is formulated, which explicitly accounts for the impact energy distribution calculated by the discrete element method (DEM). Preliminary DEM simulations of particle impact tests were first performed, which concluded that dissipation energy should be used in contrast to collision energy to accurately define the impact energy distribution. Subsequently, DEM simulations of the motion of spheres representing silica glass beads in a ball mill were performed to determine the specific breakage rate parameter, which was in good agreement with those found experimentally. An analysis of the impact energy distribution, which was only possible within context of the physically motivated specific breakage rate parameter, emphasized the importance of accounting for a threshold impact energy. Without proper assessment of the impact energy distribution, DEM simulations may lead to an erroneous evaluation of milling experiments. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2404–2415, 2014
      PubDate: 2014-04-01T11:42:11.420306-05:
      DOI: 10.1002/aic.14451
  • Control structure synthesis for operational optimization of mixed
           refrigerant processes for liquefied natural gas plant
    • Authors: Yuli Amalia Husnil; Moonyong Lee
      First page: 2428
      Abstract: The best control structures for the energy optimizing control of propane precooled mixed refrigerant (C3MR) processes were examined. A first principles-based rigorous dynamic model was developed to analyze the steady-state and dynamic behaviors of the C3MR process. The steady-state optimality of the C3MR process was then examined in a whole operation space for exploring the feasibility of the energy optimizing control for possible control structures. As a result, the temperature difference (TD) between the warm-end inlet and outlet MR streams was exploited as a promising controlled variable to automatically keep the liquefaction process close to its optimum. The closed-loop responses were finally evaluated for every possible control structure candidate. Based on the steady-state optimality and the dynamic performance evaluation, several control structures with a TD loop were proposed to be most favorable for the energy optimizing control of the C3MR process. The proposed optimality approach can be applied to any natural gas liquefaction process for determining a proper controlled variable for optimizing operation. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2428–2441, 2014
      PubDate: 2014-03-11T00:08:38.29146-05:0
      DOI: 10.1002/aic.14430
  • A superstructure-based mixed-integer programming approach to optimal
           design of pipeline network for large-scale CO2 transport
    • Authors: Chengchuan Zhou; Pei Liu, Zheng Li
      First page: 2442
      Abstract: Pipeline transport is the major means for large-scale and long-distance CO2 transport in a CO2 capture and sequestration (CCS) project. But optimal design of the pipeline network remains a challenging problem, especially when considering allocation of intermediate sites, like pump stations, and selection of pipeline routes. A superstructure-based mixed-integer programming approach for optimal design of the pipeline network, targeting on minimizing the overall cost in a CCS project is presented. A decomposition algorithm to solve the computational difficulty caused by the large size and nonlinear nature of a real-life design problem is also presented. To illustrate the capability of our models. A real-life case study in North China, with 45 emissions sources and four storage sinks, is provided. The result shows that our model and decomposition algorithm is a practical and cost-effective method for pipeline networks design. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2442–2461, 2014
      PubDate: 2014-03-24T09:34:30.665567-05:
      DOI: 10.1002/aic.14436
  • Derivative-free optimization for expensive constrained problems using a
           novel expected improvement objective function
    • Authors: Fani Boukouvala; Marianthi G. Ierapetritou
      First page: 2462
      Abstract: In this work, an algorithm for the optimization of costly constrained systems is introduced. The proposed method combines advantages of global- and local-search algorithms with new concepts of feasibility space mapping, within a framework that aims to find global solutions with minimum sampling. A global search is initially performed, during which kriging surrogate models of the objective and the feasible region are developed. A novel search criterion for locating feasibility boundaries is introduced, which does not require any assumptions regarding the convexity and nonlinearity of the feasible space. Finally, local search is performed starting from multiple locations identified by clustering of previously obtained samples. The performance of the proposed approach is evaluated through both benchmark examples and a case study from the pharmaceutical industry. A comparison of the method with commercially available software reveals that the proposed method has a competitive performance in terms of sampling requirements and quality of solution. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2462–2474, 2014
      PubDate: 2014-04-01T11:41:57.289508-05:
      DOI: 10.1002/aic.14442
  • Inventory pinch based, multiscale models for integrated planning and
           scheduling-part II: Gasoline blend scheduling
    • Authors: Pedro A. Castillo Castillo; Vladimir Mahalec
      First page: 2475
      Abstract: Integration of planning and scheduling optimizes simultaneous decisions at both levels, thereby leading to more efficient operation. A three-level discrete-time algorithm which uses nonlinear models and integrates planning and detailed scheduling is introduced: first level optimizes nonlinear blend models via multiperiod nonlinear programming (NLP), where period boundaries are initially determined by the inventory pinch points; second level uses fixed recipes (from the first level) in a multiperiod mixed-integer linear program to determine first an optimal production plan and then to optimize an approximate schedule which minimizes the total number of switches in blenders and swing tanks; third level computes detailed schedules that adhere to inventory constraints computed in the approximate schedule. If inventory infeasibilities appear at the second or the third level, the first-level periods are subdivided and blend recipes are reoptimized. Algorithm finds the same or better solutions and is substantially faster than previously published full-space continuous-time model. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2475–2497, 2014
      PubDate: 2014-04-01T13:45:58.536153-05:
      DOI: 10.1002/aic.14444
  • A novel strategy for dynamic optimization of grade transition processes
           based on molecular weight distribution
    • Authors: Jinzu Weng; Zhijiang Shao, Xi Chen, Xueping Gu, Zhen Yao, Lianfang Feng, Lorenz T. Biegler
      First page: 2498
      Abstract: To achieve different end-use properties of polymers, an industrial plant must produce several grades of the product through the same process under different operating conditions. As molecular weight distribution (MWD) is a crucial quality index of polymers, grade transition based on MWD is of great importance. Dynamic optimization of the grade transition process using MWD is a challenging task because of its large-scale nature. After analyzing the relationships among state variables during polymerization, a novel method is proposed to conduct the optimal grade transition using dynamic optimization with a small-scale moment model, combined with a steady-state calculation of the MWD. By avoiding expensive computation in dealing with dynamic MWD optimization, this technique greatly reduces the computational complexity of the process optimization. The theoretical equivalence of this simplification is also proved. Finally, an industrial high-density polyethylene slurry process is presented to demonstrate the efficiency and accuracy of the proposed strategy. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2498–2512, 2014
      PubDate: 2014-04-02T16:27:26.664432-05:
      DOI: 10.1002/aic.14445
  • Worst-case design of subsea production facilities using semi-infinite
    • Authors: Matthew D. Stuber; Achim Wechsung, Arul Sundaramoorthy, Paul I. Barton
      First page: 2513
      Abstract: The problem of designing novel process systems for deployment in extreme and hostile environments is addressed. Specifically, the process system of interest is a subsea production facility for ultra deepwater oil and gas production. The costs associated with operational failures in deepwater environments are prohibitively high and, therefore, warrant the application of worst-case design strategies. That is, prior to the construction and deployment of a process, a certificate of robust feasibility is obtained for the proposed design. The concept of worst-case design is addressed by formulating the design feasibility problem as a semi-infinite optimization problem with implicit functions embedded. A basic model of a subsea production facility is presented for a case study of rigorous performance and safety verification. Relying on recent advances in global optimization of implicit functions and semi-infinite programming, the design feasibility problem is solved, demonstrating that this approach is effective in addressing the problem of worst-case design of novel process systems. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2513–2524, 2014
      PubDate: 2014-04-03T13:42:40.800779-05:
      DOI: 10.1002/aic.14447
  • Middle distillates production via Fischer–Tropsch synthesis with
           integrated upgrading under supercritical conditions
    • Authors: Sihe Zhang; Rui Xu, Ed Durham, Christopher B. Roberts
      First page: 2573
      Abstract: A vertically aligned fixed-bed reactor system with a cascade of three sequential catalyst beds has been used to incorporate Fischer–Tropsch synthesis (FTS) in the first bed, oligomerization (O) in the second bed, and hydrocracking/isomerization (HC or C) in the third bed (FTOC). Compared to gas phase FTS (GP-FT) alone, gas phase FTS with the subsequent upgrading beds (GP-FTOC) is demonstrated to result in a reduction in the olefin selectivity, a reduction in the C26+ selectivity, and a marked enhancement in the production of branched paraffins and aromatics. Utilization of supercritical hexane as the reaction medium in supercritical FTS (SC-FT) and supercritical phase FTOC (SC-FTOC) resulted in a significant reduction in both CH4 selectivity and CO2 selectivity. Interestingly, significant amounts of aldehydes and cyclo-paraffins were collected in SC-FT and in SC-FTOC, respectively, while not being observed in traditional gas phase operation (both GP-FT and GP-FTOC). © 2014 American Institute of Chemical Engineers AIChE J, 60: 2573–2583, 2014
      PubDate: 2014-05-22T10:14:18.666798-05:
      DOI: 10.1002/aic.14493
  • Separation of methanol-tetrahydrofuran mixtures by heteroazeotropic
           distillation and pervaporation
    • Authors: Giuseppe Genduso; Antonio Amelio, Patricia Luis, Bart Bruggen, Steven Vreysen
      First page: 2584
      Abstract: The experimental investigation of the separation of tetrahydrofuran-methanol by heteroazeotropic-batch-distillation and methanol-hexane by pervaporation is presented. In particular for this last task, four different specialty commercial membranes were tested (varying feed concentration and temperature). The “pore filling” PolyAn membranes show methanol permeance values higher than 5100 GPU (Typ M2®); separation factor of 19; and a selectivity of about 119 (Typ M1®). From the results, a coupling phenomenon was observed. An assessment of the temperature effect in the pervaporation process corroborates the hypothesis of the presence of a coupling phenomenon. Finally, a discussion is made on two industrial scale units for the separation of the same mixture: a system of a distillation column integrated with a decanter and stand-alone pervaporation unit. The energetic comparison shows that when using pervaporation a large reduction of the energetic consumption compared to a conventional distillation system (up to 29%) can be obtained. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2584–2595, 2014
      PubDate: 2014-03-18T09:30:12.508651-05:
      DOI: 10.1002/aic.14432
  • A model for the devolatilization of EPDM rubber in a series of steam
           stripping vessels
    • Authors: Angelica J. B. Francoeur; Hadiseh Karimi, Kim B. McAuley, Luigi D'Agnillo
      First page: 2596
      Abstract: A mathematical model was developed for the multitank stripping section of industrial ethylene propylene diene monomer (EPDM) rubber processes. Experiments were conducted to determine Henry's law coefficients and diffusivities for hexane solvent and 5-ethylidene-2-norbornene (ENB) comonomer in EPDM particles. Equivalent radii for diffusion within the particles were also determined. A model was developed to predict solvent and comonomer concentrations in a single particle as it moves through a series of tanks with different operating conditions. A second, more-complicated model was then developed to account for a continuous flow stirred tank residence time distribution for the particles in the tanks. Data from three industrial plants were used to estimate parameters and assess the models' predictive ability. Typical prediction errors are 0.90 wt % for residual hexane and 0.14 wt % for residual ENB. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2596–2606, 2014
      PubDate: 2014-04-01T11:45:15.278155-05:
      DOI: 10.1002/aic.14448
  • Highly scalable ZIF-based mixed-matrix hollow fiber membranes for advanced
           hydrocarbon separations
    • Authors: Chen Zhang; Kuang Zhang, Liren Xu, Ying Labreche, Brian Kraftschik, William J. Koros
      First page: 2625
      Abstract: ZIF-8/6FDA-DAM, a proven mixed-matrix material that demonstrated remarkably enhanced C3H6/C3H8 selectivity in dense film geometry, was extended to scalable hollow fiber geometry in the current work. We successfully formed dual-layer ZIF-8/6FDA-DAM mixed-matrix hollow fiber membranes with ZIF-8 nanoparticle loading up to 30 wt % using the conventional dry-jet/wet-quench fiber spinning technique. The mixed-matrix hollow fibers showed significantly enhanced C3H6/C3H8 selectivity that was consistent with mixed-matrix dense films. Critical variables controlling successful formation of mixed-matrix hollow fiber membranes with desirable morphology and attractive transport properties were discussed. Furthermore, the effects of coating materials on selectivity recovery of partially defective fibers were investigated. To our best knowledge, this is the first article reporting successful formation of high-loading mixed-matrix hollow fiber membranes with significantly enhanced selectivity for separation of condensable olefin/paraffin mixtures. Therefore, it represents a major step in the research area of advanced mixed-matrix membranes. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2625–2635, 2014
      PubDate: 2014-05-29T22:07:37.919913-05:
      DOI: 10.1002/aic.14496
  • Hydrophobic–hydrophilic
           polydivinylbenzene/polyacryldiethylenetriamine interpenetrating polymer
           networks and its adsorption performance toward salicylic acid from aqueous
    • Authors: Xiaomei Wang; Xiaolei Liang, Jianhan Huang, You-Nian Liu
      First page: 2636
      Abstract: Hydrophobic–hydrophilic interpenetrating polymer networks (IPNs) composed of polydivinylbenzene (PDVB) and polyacryldiethylenetriamine (PADETA) were prepared and its adsorption performance toward salicylic acid was studied from aqueous solutions. The structure of PDVB/PADETA IPNs was characterized by Fourier transform infrared spectroscopy, N2 adsorption–desorption isotherms, weak basic exchange capacity, and swelling ratio, respectively. The results indicated that PDVB/PADETA IPNs possessed both hydrophobic and hydrophilic properties and they were much superior to the hydrophobic PDVB and the hydrophilic PADETA in adsorption of salicylic acid from aqueous solutions. The Freundlich model was more appropriate for fitting the equilibrium data than the Langmuir model and the isosteric enthalpy decreased with increment of the equilibrium uptakes. The breakthrough dynamic capacity of salicylic acid on PDVB/PADETA IPNs was 77.27 mg/mL wet resin at an initial concentration of 650.4 mg/L and a flow rate of 7.2 BV/h (bed volume, 1 BV = 10 mL) and the saturated dynamic capacity was calculated to be 93.28 mg/mL wet resin. One hundred and forty milliliter of 0.01 mol/L of sodium hydroxide (w/v) and 40% of ethanol (v/v) could regenerate the resin column completely. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2636–2643, 2014
      PubDate: 2014-03-07T14:20:36.794718-05:
      DOI: 10.1002/aic.14429
  • Rheological evaluation of kinetic hydrate inhibitors in NaCl/n-heptane
    • Authors: Hassan Sharifi; Savvas G. Hatzikiriakos, Peter Englezos
      First page: 2654
      Abstract: The performance of polyvinylpyrrolidone (PVP) and polyvinylcaprolactam (PVCap) as kinetic hydrate inhibitors (KHIs) in the presence of NaCl and n-heptane was evaluated by using a high-pressure cell in conjunction with a rotational rheometer. The addition of KHIs was found to prolong the induction time and decrease the hydrate growth. On the other hand, hydrates agglomerated more readily. PVP performed more efficiently than PVCap in delaying nucleation time but PVCap controlled the growth and delayed agglomeration more effectively. Addition of n-heptane to the system increased induction time and reduced growth. Unexpectedly, addition of KHIs in the presence of n-heptane decreased nucleation time but controlled growth effectively. Meanwhile, hydrate particles remained dispersed more efficiently and no agglomeration was detected. These observations confirm that high-pressure rheology is an additional laboratory assessment tool to evaluate KHIs under ocean field conditions. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2654–2659, 2014
      PubDate: 2014-03-13T16:31:20.299956-05:
      DOI: 10.1002/aic.14433
  • Viscosity and rheological behavior of microbubbles in capillary tubes
    • Authors: Mohammad Mehdi Shams; Mingzhe Dong, Nader Mahinpey
      First page: 2660
      Abstract: The viscosity of microbubbles has been measured in capillary tubes. Experiments were conducted in tubes of different diameters and lengths, with a constant microbubble concentration. The effects of bubble void fraction and size distribution on the viscosity of microbubbles were also investigated. Microbubbles demonstrate shear-thinning non-Newtonian behavior. The viscosity of microbubbles decreases with a decrease in tube diameter and bubble void fraction, and with an increase in tube length. Although viscosity changes with tube dimensions, the flow index (n′) is only influenced by the microbubble void fraction. It is also found that bubble size distribution in the range (1–12 µm) used in this study does not affect the viscosity of microbubbles. The data were then used to develop a correlation to predict viscosity of microbubbles, which represents the experimental viscosity data with an absolute average relative deviation less than 1.3%. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2660–2669, 2014
      PubDate: 2014-03-17T10:35:42.081272-05:
      DOI: 10.1002/aic.14434
  • Application of taylor dispersion technique to measure mutual diffusion
           coefficient in hexane + bitumen system
    • Authors: Mohsen Ghanavati; Hassan Hassanzadeh, Jalal Abedi
      First page: 2670
      Abstract: A novel approach with fewer technical and analytic limitations in liquid solvent-bitumen diffusion studies is used in this article. The Taylor dispersion technique was selected for its convenient short run time experiments and reliable data analysis to find mutual diffusion coefficients in a hexane + bitumen mixture. For the first time, the infinite-dilution molecular diffusion coefficients of bitumen in hexane were measured in both the presence and relative absence of asphaltene particles in the solution at atmospheric pressure and temperatures of 303.15, 310.15, and 317.15 K. The polydisperse nature of bitumen was clearly revealed. Results were compared with common predictive tools. Also, the asphaltene surface charge in the hexane precipitating solvent was demonstrated. Through concentration dependency investigations at atmospheric pressure and 303.15 K, it was determined that the mutual diffusion coefficients monotonically decrease as the viscosity of mixture increases within the studied 0–34% volumetric concentration of bitumen. The Taylor dispersion technique shows great potential for diffusion studies of liquid solvent-bitumen systems. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2670–2682, 2014
      PubDate: 2014-03-17T10:23:25.026307-05:
      DOI: 10.1002/aic.14438
  • Spread and recoiling of liquid droplets impacting solid surfaces
    • Authors: Xuan Gao; Ri Li
      First page: 2683
      Abstract: The impact of water droplets on solid surfaces is studied experimentally and theoretically. Theoretical equations based on energy conservation are developed. In our theoretical study, the droplet is modeled as a ring-like shape, which matches the dynamic shape of droplets observed from our experimental tests. In the analysis of energy conservation, the nonuniform distribution of pressure inside the deformed droplet is taken into account by introducing a flow potential energy term in the theoretical equations. To derive viscous dissipation for recoiling, a viscous layer coefficient is introduced. Its values for the tests using smooth surfaces are found to be within a small range. Both theoretical predictions and experimental data show significant influence of surface wettability on maximum spread and recoiling process. With the increase of advancing contact angle, surface energy shows a decreasing trend, whereas flow potential energy shows an increasing trend and becomes significant for hydrophobic surfaces. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2683–2691, 2014
      PubDate: 2014-03-18T09:02:29.105447-05:
      DOI: 10.1002/aic.14440
  • Flow of concentrated suspension through oblique bifurcating channels
    • Authors: Mallela Mallikarjuna Reddy; Anugrah Singh
      First page: 2692
      Abstract: Suspensions of solid particles in viscous fluid flowing through bifurcating channels are encountered in various industrial processes and biological applications. This work reports the detailed numerical simulations of shear-induced particle migration in oblique bifurcating channels. The effect of particle concentration, bifurcation angle, and flow rate on the partitioning of bulk flow and particles in the downstream branches is studied. It was observed that the particle distribution in the downstream branches does not follow the flow distribution due to shear-induced particle migration. The velocity and concentration profile for suspension flow were observed to be symmetric in the inlet branch but asymmetric in the daughter branches. The degree of asymmetry and bluntness of velocity profile was observed to depend on the bulk particle concentration and bifurcation angle. The reported results could be useful in the design of flow devices handling suspension transport in bifurcating channels. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2692–2704, 2014
      PubDate: 2014-03-25T13:40:46.067303-05:
      DOI: 10.1002/aic.14446
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