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 AIChE Journal   [SJR: 1.098]   [H-I: 104]   [22 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 0001-1541 - ISSN (Online) 1547-5905    Published by John Wiley and Sons  [1608 journals]
• Efficient tuning of microstructure and surface chemistry of nanocarbon
catalysts for ethylbenzene direct dehydrogenation
• Authors: Zhongkui Zhao; Yitao Dai, Guifang Ge, Guiru Wang
Abstract: A facile and scalable approach to efficiently tune microstructure and surface chemical properties of N‐doped carbocatalysts through the controlled glucose hydrothermal treatment with diverse parameters and subsequent pyrolysis of pretreated carbonaceous materials with melamine (GHT‐PCM) was presented. Various characterization techniques including HRTEM, BET, XRD, XPS, Raman and FT‐IR were employed to investigate the effect of prior GHT on the microstructure and surface chemical properties of N‐doped carbocatalysts, as well as to reveal the relationship between catalyst nature and catalytic performance in oxidant‐ and steam‐free direct dehydrogenation of ethylbenzene (DDH) for styrene production. It was found that the GHT process and its conditions significantly affect microstructure and surface chemical properties of the N‐doped carbocatalysts, which subsequently influences their catalytic performance in DDH reaction dramatically. Interestingly, the prior GHT can remove the carbon nitride layer formed on parent nanocarbon in the process of melamine pyrolysis, produce structural defects and tune surface element component, through the “detonation” of polysaccharide coating on nanocarbon. The as‐prepared N‐doped CNT (M‐Glu‐CNT) by the established GHT‐PCM approach in this work demonstrates higher catalytic performance (4.6 mmol g−1 h−1 styrene rate with 98% selectivity) to the common N‐doped CNT (M‐CNT, 3.4 mmol g−1 h−1 styrene rate with 98.2% selectivity) as well as to pristine CNT (2.8 mmol g−1 h−1 styrene rate with 96.8% selectivity), mainly ascribed to increased structural defects, enriched surface ketonic C=O groups, and improved basic properties from N‐doping on the M‐Glu‐CNT, those strongly depend on GHT conditions. The excellent catalytic performance of the developed M‐Glu‐CNT catalyst endows it with great potential for future clean production of styrene via oxidant‐ and steam‐free conditions. Moreover, the directed GHT‐PCM strategy can be extended to the other N‐doped carbonaceous materials with enhanced catalytic performance in diverse reactions by tuning their microstructure and surface chemistry. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-22T17:40:02.013477-05:
DOI: 10.1002/aic.14853

• Control of spatially distributed processes with unknown
transport‐reaction parameters via two layer system adaptations
• Authors: Davood Babaei Pourkargar; Antonios Armaou
PubDate: 2015-04-22T17:39:37.56325-05:0
DOI: 10.1002/aic.14852

• Effect of ionic strength on bubble coalescence in inorganic salt and
seawater solutions
• Authors: J.M. Sovechles; K.E. Waters
PubDate: 2015-04-22T17:39:16.488239-05:
DOI: 10.1002/aic.14851

• A multi‐objective optimization framework for design of integrated
biorefineries under uncertainty
• Authors: A. Geraili; J.A. Romagnoli
PubDate: 2015-04-22T17:32:09.313775-05:
DOI: 10.1002/aic.14849

• Thermal conductivity of nanofluids: Effect of brownian motion of
nanoparticles
• Authors: Rachid Chebbi
PubDate: 2015-04-22T17:31:46.779486-05:
DOI: 10.1002/aic.14847

• A letter to the editor
• Authors: Yimin Xuan
PubDate: 2015-04-22T17:31:27.819205-05:
DOI: 10.1002/aic.14848

• Modeling permporometry of mesoporous membranes using dynamic mean field
theory
• Authors: A. Rathi; J. R. Edison, D. M. Ford, P. A. Monson
PubDate: 2015-04-21T00:43:28.411103-05:
DOI: 10.1002/aic.14846

• Process synthesis for cascade refrigeration system based on exergy
analysis†
• Authors: Ha Dinh; Jian Zhang, Qiang Xu
PubDate: 2015-04-17T16:10:47.092361-05:
DOI: 10.1002/aic.14843

• Numerical study of pipeline restart of weakly compressible irreversibly
thixotropic waxy crude oils
• Authors: Lalit Kumar; Chris Lawrence, Yansong Zhao, Kristofer Paso, Brian Grimes, Johan Sjöblom
PubDate: 2015-04-17T16:10:12.461041-05:
DOI: 10.1002/aic.14844

• High‐throughput and comprehensive prediction of H2 adsorption in
metal‐organic frameworks under various conditions
• Authors: Yu Liu; Shuangliang Zhao, Honglai Liu, Ying Hu
Abstract: High‐throughput prediction of H2 adsorption in MOF materials has been extended from a few specific conditions to the whole T, p space. The prediction is based on a classical density functional theory and has been implemented over 712 MOFs in 441 different conditions covering a wide range. Some testing materials show excellent behavior at low temperatures and obvious improvement at high temperatures compared to conventional MOFs. The structures of the best MOFs at high and low temperatures are totally different. Linear and nonlinear correlations between the two Langmuir parameters have been found at high and low temperatures, respectively. According to the analysis of the excess uptake, we found that the saturated pressure increases along with temperature in the low temperature region but decreases in the high temperature region. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-17T16:09:51.556324-05:
DOI: 10.1002/aic.14842

• Thermal transport model of a sorbent particle undergoing
calcination–carbonation cycling
• Authors: Lindsey Yue; Wojciech Lipiński
Abstract: A numerical model coupling transient radiative, convective, and conductive heat transfer, mass transfer, and chemical kinetics of heterogeneous solid–gas reactions has been developed for a semi‐transparent, non‐uniform, and non‐isothermal particle undergoing cyclic thermochemical transformations. The calcination–carbonation reaction pair for calcium oxide looping is selected as the model cycle because of its suitability for solar‐driven carbon dioxide capture. The analyzed system is a single, porous particle undergoing thermochemical cycling in an idealized, reactor‐like environment. The model is used to investigate two cases distinguished by the length of the calcination and carbonation periods. The calcination–carbonation process for a single particle is shown to become periodic after three cycles. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-16T04:27:19.167469-05:
DOI: 10.1002/aic.14840

• Investigation of the Heat Transfer Intensification Mechanism for a New
Fluidized Catalyst Cooler
• Authors: Xiuying Yao; Xiao Han, Yongmin Zhang, Chunxi Lu
Abstract: A small cold model was employed to investigate the heat transfer mechanism for a new fluidized catalyst cooler. Local heat transfer coefficients (h) and tube surface hydrodynamics were systematically measured by a specially designed heat tube and an optical fiber probe. The higher total h further validated the feasibility of the heat transfer intensification method employed in the new catalyst cooler, which indicated that the induced higher packet renewal frequency due to the non‐uniform gas distribution played a dominant role in its increased hs. Strongest heat transfer intensification effect was located at r/Rw>0.8 below the heat transfer intensification height. The changes of the mean packet residence time in the radial and axial directions and with superficial gas velocity were all agreeable with the measured hs according to the packet renewal theory. This further demonstrated the feasibility of the experimental method for tube surface hydrodynamics. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-15T00:41:02.872059-05:
DOI: 10.1002/aic.14841

• Aggregation of silica nanoparticles in an aqueous suspension
• Authors: Lande Liu
Abstract: Aggregation affects the stability of the nanoparticles in fluids. For hydrophilic particles in aqueous suspensions, zeta potential becomes a common measure to control the stability of the particles. However, it is not clear how zeta potential impacts on the interaction of the particles during their close range contact when the hydration repulsion arises strongly. This paper demonstrates a method that uses the kinetic theory of aggregation for an aggregation system of changing zeta potential to determine the hydration repulsion and the aggregation efficiency. It was found that the hydration repulsion has an equivalent electrical potential of 30 mV on the stem surface of the particles and an exponential decay length of 2.77 Å. This hydration potential is equivalent to 12 mV zeta potential and contributes 29% to the aggregation coefficient that is 5.5 × 10−6 for a 30 mV zeta potential stabilised silica particle suspension. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-09T16:14:21.241866-05:
DOI: 10.1002/aic.14839

• A robust mixed‐conducting multichannel hollow fiber membrane reactor
• Authors: Jiawei Zhu; Shaobin Guo, Gongping Liu, Zhengkun Liu, Zhicheng Zhang, Wanqin Jin
PubDate: 2015-04-09T16:14:01.577761-05:
DOI: 10.1002/aic.14835

• Accuracy and optimal sampling in monte carlo solution of population
balance equations
• Authors: Xi Yu; Michael J Hounslow, Gavin K Reynolds
Abstract: Implementation of a Monte Carlo simulation for the solution of population balance equations requires choice of initial sample number (N0), number of replicates (M) and number of bins for probability distribution reconstruction (n). It is found that Squared Hellinger Distance, H2, is a useful measurement of the accuracy of MC simulation, and can be related directly to N0, M and n. Asymptotic approximations of H2 are deduced and tested for both 1D and 2D PBEs with coalescence. The CPU cost, C, is found in a power‐law relationship, C= aMN0b, with the CPU cost index, b, indicating the weighting of N0 in the total CPU cost. n must be chosen to balance accuracy and resolution. For fixed n, M×N0 determines the accuracy of MC prediction; if b>1, then the optimal solution strategy uses multiple replications and small sample size. Conversely if 0
PubDate: 2015-04-09T16:13:41.436584-05:
DOI: 10.1002/aic.14837

• A hierarchical method to integrated solvent and process design of physical
CO2 absorption using the SAFT‐γ mie approach
• Authors: J. Burger; V. Papaioannou, S. Gopinath, G. Jackson, A. Galindo, C. S. Adjiman
Abstract: Molecular‐level decisions are increasingly recognised as an integral part of process design. Finding the optimal process performance requires the integrated optimisation of process and solvent chemical structure, leading to a challenging mixed‐integer nonlinear programming (MINLP) problem. We present the formulation of such problems when using a group contribution version of the statistical associating fluid theory (SAFT‐ γ Mie) to predict the physical properties of the relevant mixtures reliably over process conditions. To solve the challenging MINLP, a novel hierarchical methodology for integrated process and solvent design (HiOpt) is presented. Reduced models of the process units are developed and used to generate a set of initial guesses for the MINLP solution. The methodology is applied to the design of a physical absorption process to separate carbon dioxide from methane, using a large selection of ethers as the molecular design space. The solvents with best process performance are found to be poly(oxymethylene)dimethylethers. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-09T16:13:22.051972-05:
DOI: 10.1002/aic.14838

• Modeling heterogeneous photocatalytic inactivation of E.coli using
suspended and immobilized TiO2 reactors
• Authors: M. Kacem; G. Plantard, N. Wery, V. Goetz
PubDate: 2015-04-09T16:13:03.077146-05:
DOI: 10.1002/aic.14834

• Co‐gasification of woody biomass and sewage sludge in a
fixed‐bed downdraft gasifier
• Authors: Zhehan Ong; Yongpan Cheng, Thawatchai Maneerung, Zhiyi Yao, Yanjun Dai, Yen Wah Tong, Chi‐Hwa Wang
Abstract: In this work, experimental and numerical studies of co‐gasification of woody biomass and sewage sludge have been carried out. The gasification experiments were performed in a fixed‐bed downdraft gasifier and the experimental results show that 20 wt. % dried sewage sludge in the feedstock was effectively gasified to generate producer gas comprising over 30 vol. % of syngas with an average lower heating value of 4.5 MJ/Nm3. Further increasing sewage sludge content to 33 wt. % leads to the blockage of gasifier, which is resulted from the formation of agglomerated ash. The numerical models were then developed to simulate the reactions taking place in four different zones of the gasifier (i.e. drying, pyrolysis, combustion and reduction zones) and to predict the producer gas composition and cold gas efficiency (CGE). The deviation between the numerical and experimental results obtained in this study was lower than 10%. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-09T16:12:30.486522-05:
DOI: 10.1002/aic.14836

• Erratum
• PubDate: 2015-04-09T10:21:34.009885-05:
DOI: 10.1002/aic.14811

• Optimal distribution of temperature driving forces in
low‐temperature heat transfer
• Authors: Bjørn Austbø; Truls Gundersen
Abstract: This paper provides a fairly extensive review of research on optimal distribution of driving forces in heat transfer processes. Four different guidelines for specifying the temperature profiles in heat exchangers have been compared. Not surprisingly, the irreversibilities due to heat transfer were found to be minimized when the temperature difference is proportional to the absolute temperature. Comparing a design with an optimal temperature profile and a design with a uniform temperature difference throughout the heat exchanger, sensitivity analyses illustrated that savings in irreversibilities increase with decreasing temperature level and increasing temperature span for the cooling load. Heat exchanger size was found to be of negligible importance. The results indicated that optimal utilization of heat exchanger area is of little importance for processes operating above ambient temperature, while significant savings can be obtained by optimal distribution of temperature driving forces in processes below ambient temperature. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-07T17:44:18.558876-05:
DOI: 10.1002/aic.14832

• Integration of scheduling, design and control of multi‐product
chemical processes under uncertainty
• Authors: Bhushan P. Patil; Eduardo Maia, Luis A. Ricardez‐Sandoval
PubDate: 2015-04-07T17:44:00.242568-05:
DOI: 10.1002/aic.14833

• Simulation study of the effect of wall roughness on the dynamics of
granular flows in rotating semi‐cylindrical chutes
• Authors: S.S. Shirsath; J.T. Padding, H.J.H. Clercx, J.A.M. Kuipers
Abstract: A discrete element model (DEM) is used to investigate the behavior of spherical particles flowing down a semi‐cylindrical rotating chute. The DEM simulations are validated by comparing with Particle Tracking Velocimetry (PTV) results of spherical glass particles flowing through a smooth semi‐cylindrical chute at different rotation rates of the chute. The DEM model predictions agree well with experimental results of surface velocity and particle bed height evolution. The validated DEM model is used to investigate the influence of chute roughness on the flow behaviour of monodisperse granular particles in rotating chutes. To emulate different base roughnesses, a rough base is constructed out of a square close packing of fixed spherical particles with a diameter equal to, smaller, or larger than the flowing particles. Finally, the DEM model is used to study segregation in a binary density mixture for different degrees of roughness of the chute. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-07T17:43:42.997403-05:
DOI: 10.1002/aic.14828

• Consideration of low viscous droplet breakage in the framework of the wide
energy spectrum and the multiple fragments
• Authors: Luchang Han; Shenggao Gong, Yaowen Ding, Jin Fu, Ningning Gao, He'an Luo
Abstract: An improved model for low viscous droplet breakage has been developed. Unlike the previous work that considered the inertia subrange and adopted the assumption of binary breakage, this work considered the breakage of droplets in the framework of the multiple fragments and the wide energy spectrum (i.e. including the dissipation range, the inertia subrange and the energy containing range simultaneously). The previous interactions between the droplet and the surrounding fluid have been considered through introducing the interaction forces. The effect of the surface deformation and oscillation resulting from these interactions on the constraints of multiple breakages has been accounted for. These factors have been neglected in the existing models. The wide energy spectrum distribution was found to have an important effect on the non‐monotone evolution of breakage frequency with increasing parent droplet size. The cumulative volume fractions predicted by this work showed a better agreement with the experimental data. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-07T17:42:51.464663-05:
DOI: 10.1002/aic.14830

• An electrolyte CPA equation of state for mixed solvent electrolytes
• Authors: Bjørn Maribo‐Mogensen; Kaj Thomsen, Georgios M. Kontogeorgis
Abstract: Despite great efforts over the past decades, thermodynamic modeling of electrolytes in mixed solvents is still a challenge today. The existing modeling frameworks based on activity coefficient models are data‐driven and require expert knowledge to be parameterized. It has been suggested that the predictive capabilities could be improved through the development of an electrolyte equation of state. In this work, the Cubic Plus Association (CPA) Equation of State is extended to handle mixtures containing electrolytes by including the electrostatic contributions from the Debye‐Hückel and Born terms using a self‐consistent model for the static permittivity. A simple scheme for parameterization of salts with a limited number of parameters is proposed and model parameters for a range of salts are determined from experimental data of activity and osmotic coefficients as well as freezing point depression. Finally, the model is applied to predict VLE, LLE, and SLE in aqueous salt mixtures as well as in mixed solvents. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-07T17:42:34.244232-05:
DOI: 10.1002/aic.14829

• Characterization of liquid‐liquid dispersions with variable

• Authors: Michal Vonka; Miroslav Soos
Abstract: Sustaining stable liquid‐liquid dispersion with the desired drop size still relies on experimental correlations, which do not reflect our understanding of the underlying physics and have limited prediction capability. The complex behaviour of liquid‐liquid dispersions inside a stirred tank, which is equipped with a Rushton turbine, was characterized by a combination of Computational Fluid Dynamics (CFD) and Population Balance Equations (PBE). PBE took into account both the drop coalescence and breakup. With increasing drop viscosity the resistance to drop breakage increases, which was introduced by the local criteria for drop breakup in the form of the local critical Webber number (). The dependency of on the drop viscosity was derived from the experimental data available in the literature. Predictions of Sauter mean diameter agree well with the experimentally measured values allowing prediction of mean drop size as a function of variable viscosity, interfacial tension and stirring speed. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-07T17:42:21.164492-05:
DOI: 10.1002/aic.14831

• A generalized procedure for the prediction of multicomponent adsorption
equilibria
• Authors: Austin Ladshaw; Sotira Yiacoumi, Costas Tsouris
PubDate: 2015-04-07T11:11:06.966511-05:
DOI: 10.1002/aic.14826

• Pilot‐scale studies of process intensification by cyclic
distillation
• Authors: Bogdan V. Maleta; Alexander Shevchenko, Olesja Bedruk, Anton A. Kiss
PubDate: 2015-04-06T23:55:29.612385-05:
DOI: 10.1002/aic.14827

• Experimental Studies and Modeling of CO2 Solubility in High Temperature
Aqueous CaCl2, MgCl2, Na2SO4, and KCl Solutions
• Authors: Haining Zhao; Robert M. Dilmore, Serguei N. Lvov
Abstract: The phase equilibria of CO2 and aqueous electrolyte solutions are important to various chemical‐, petroleum‐ and environmental‐related technical applications. In this study, we measured CO2 solubility in aqueous CaCl2, MgCl2, Na2SO4 and KCl solutions at a pressure of 15 MPa, the temperatures from 323 to 423 K, and the ionic strength from 1 to 6 mol kg−1. Based on the measured experimental CO2 solubility, the previous developed fugacity‐activity thermodynamic model for the CO2‐NaCl‐H2O system was extended to account for the effects of different salt specieson CO2 solubility in aqueous solutions at temperatures up to 523 K, pressures up to 150 MPa, and salt concentrations up to saturation. Comparisons of different models against literature data reveal a clear improvement of the proposed PSUCO2 model in predicting CO2 solubility in aqueous salt solutions. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-04T03:21:25.36965-05:0
DOI: 10.1002/aic.14825

• A low‐disturbance nonequilibrium molecular dynamics algorithm
applied to the determination of thermal conductivities
• Authors: Filipe A. Furtado; Charlles R. A. Abreu, Frederico W. Tavares
Abstract: A new nonequilibrium molecular dynamics algorithm is proposed for the determination of thermal conductivity and other transport properties. The proposed algorithm aims at diminishing the energy drift problem observed in this type of method while conserving linear momentum and being compatible with constrained molecules. The features of the proposed algorithm are evaluated by determining thermal conductivities of water at 323 K, n‐octane at 300 K, and argon close to its triple point, and by comparing these results with those obtained using established methods. The analysis of systems presenting diverse molecular characteristics allowed us to assess the usefulness of the proposed algorithm. The energy drift and temperature variation were reduced in the range of 10–80%, depending on the parameters of the proposed algorithm and the characteristics of the system. The determined thermal conductivities showed good agreement when compared to experimental and simulation data. © 2015 American Institute of Chemical Engineers AIChE J, 2015
PubDate: 2015-04-03T10:17:58.709766-05:
DOI: 10.1002/aic.14803

• Thermodynamics of protein aqueous solutions: From the structure factor to
the osmotic pressure
• Authors: Luís Fernando Mercier Franco; Cristiano Luis Pinto de Oliveira, Pedro de Alcântara Pessôa Filho
Abstract: An analytical expression for the structure factor for globular proteins in aqueous solution is presented in this work. This expression was obtained considering a potential given by the sum of a hard core, a van der Waals attractive and a screened Coulomb contribution. Experimental data of Small Angle X‐Ray Scattering for bovine serum albumin in aqueous solutions containing sodium salts at different protein concentrations and pH values are also presented. The developed expression for the structure factor describes accurately these experimental data provided a dependence of the attractive parameter on protein concentration is established. An expression for the osmotic pressure was derived from the structure factor. With attractive parameters adjusted from X‐ray scattering data, the osmotic pressure of bovine serum albumin aqueous solutions could be predicted with very good agreement with experimental data. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-03T06:21:32.372128-05:
DOI: 10.1002/aic.14802

• Towards economical purification of styrene monomers: Eggshell Mo2C for
front‐end hydrogenation of phenylacetylene
• Authors: Min Pang; Zhengfeng Shao, Wei Xia, Xinkui Wang, Changhai Liang
Abstract: We describe an eggshell Mo2C catalyst which is designed from the rapid combination of molybdate with melamine. In contrast to Pd‐based catalysts, the eggshell Mo2C operates effectively with a wide concentration window in high‐temperature gas phase hydrogenation of phenylacetylene thus an economical and energy‐efficient front‐end purification of styrene monomers might be possible. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-02T18:47:16.789707-05:
DOI: 10.1002/aic.14822

• A generalized model to predict minimum particle transport velocities in
multiphase air‐water horizontal pipes
• Authors: Kamyar Najmi; Alan L. Hill, Selen Cremaschi, Brenton S. McLaury, Siamack A. Shirazi
Abstract: A new model is proposed to predict minimum flow rates required to constantly move particles in both intermittent and stratified flow regimes. The new model consists of a single‐phase flow model along with an appropriate length scale to be extended to multiphase flow regime. A comparison of the new model with experimental data in a multiphase air‐water flow shows that the new model is able to predict minimum flow rates well for a wide range of operating conditions. The new model can capture the effects of particle size, particle concentration and pipe size as confirmed by experimental data. A comparison of the new model with previously proposed models in the literature shows that the new model improves critical velocity predictions significantly. Moreover, the new model is the only model that takes into account the effect of particle concentration and can predict critical velocity in both intermittent and stratified flow regimes. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-02T18:46:35.130779-05:
DOI: 10.1002/aic.14824

• Simultaneous integration of water and energy in heat‐integrated
water allocation networks
• Authors: Zuming Liu; Yiqing Luo, Xigang Yuan
PubDate: 2015-04-02T18:46:09.148186-05:
DOI: 10.1002/aic.14823

• Numerical study of turbulent liquid‐liquid dispersions
• Authors: A.E. Komrakova; D. Eskin, J.J. Derksen
Abstract: A numerical approach is developed to gain fundamental insight in liquid‐liquid dispersion formation under well‐controlled turbulent conditions. The approach is based on a free energy lattice Boltzmann equation method, and relies on detailed resolution of the interaction of the dispersed and continuous phase at the microscopic level, including drop breakup and coalescence. The capability of the numerical technique to perform direct numerical simulations of turbulently agitated liquid‐liquid dispersions is assessed. Three‐dimensional simulations are carried out in fully‐periodic cubic domains with grids of size 1003‐10003. The liquids are of equal density. Viscosity ratios (dispersed phase over continuous phase) are in the range 0.3 to 1.0. The dispersed phase volume fraction varies from 0.001 to 0.2. The process of dispersion formation is followed and visualized. The size of each drop in the dispersion is measured in‐line with no disturbance of the flow. However, the numerical method is plagued by numerical dissolution of drops that are smaller than 10 times the lattice spacing. It is shown that to mitigate this effect it is necessary to increase the resolution of the Kolmogorov scales, such as to have a minimum drop size in the range 20‐30 lattice units [lu]. Four levels of Kolmogorov length scale resolution have been considered\eta_K=1, 2.5, 5 and 10 [lu]. In addition, the numerical dissolution reduces if the concentration of the dispersed phase is increased. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-02T18:45:43.104236-05:
DOI: 10.1002/aic.14821

• On the simultaneous description of h‐bonding and dipolar
interactions with point charges in force field models
• Authors: Kai Langenbach; Cemal Engin, Steffen Reiser, Martin Horsch, Hans Hasse
Abstract: H‐bonding and polar interactions occur together in real fluids, but are of different nature and have different effects on macroscopic properties. Nevertheless, both are usually described by point charges in force field models. We show that, despite this, the two effects can be separated. We study a simple model fluid: a single Lennard‐Jones site with two opposing point charges q placed in the center of the Lennard‐Jones site and at a distance d. By suitably varying both d and q the dipole moment μ is kept constant. Both μ and d are systematically varied to study the properties of the resulting models, including H‐bonding, which is determined using a geometric criterion from literature. We show that d can be used for tuning the H‐bonding strength and, thus, polarity and H‐bonding can be adjusted individually. The study of a second related model with symmetrically positioned point charges does not reveal this separation. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-02T18:45:17.356024-05:
DOI: 10.1002/aic.14820

• Enhanced gravimetric CO2 capacity and viscosity for ionic liquids with
cyanopyrrolide anion
• Authors: Paul Brown; Burcu E. Gurkan, T. Alan Hatton
Abstract: “Ionic Liquids are considered as alternative solvents for the separation of CO2 from flue gas due mainly to their CO2 affinity and thermal stability. This paper systematically investigates the cation architecture in a matrix of ammonium and mostly phosphonium‐based ionic liquids with 2‐cyanopyrrolide as the anion to evaluate its impact on gravimetric CO2 absorption capacity, viscosity and thermal stability; the three fundamental properties vital for application realization. Among the investigated ILs, [P2,2,2,8][2‐CNpyr] demonstrated the lowest viscosity, 95 cP at 40 ºC, and highest CO2 uptake, 114 mg CO2/g IL at 40 ºC. Combined effects of asymmetry and the optimized chain lengths also resulted in improved thermal stability for [P2,2,2,8][2‐CNpyr], with a mass loss rate of 1.35 x 10−6 g h−1 (0.0067 mass % h−1) at 80 ºC.” This article is protected by copyright. All rights reserved.
PubDate: 2015-04-01T15:23:17.597522-05:
DOI: 10.1002/aic.14819

• Dew‐point measurements for water in compressed carbon dioxide
• Authors: Christopher W. Meyer; Allan H. Harvey
Abstract: When transporting CO2 for sequestration, it is important to know the water dew point in order to avoid condensation that can lead to corrosion. We have constructed a flow apparatus to measure the water content at saturation in a compressed gas. A saturator humidifies the flowing gas by equilibrating it with liquid water. Then, a gravimetric hygrometer measures the water mole fraction of the humid gas. We report dew‐point data for H2O in CO2 on six isotherms between 10 °C and 80 °C at pressures from 0.5 MPa to 5 MPa. Our uncertainties in water content at the dew point (expanded uncertainty with coverage factor k=2) are on average 0.3%, significantly smaller than in any previous work. The data have been analyzed to extract the interaction second virial coefficient; our values are consistent with the theoretical estimates of Wheatley and Harvey but have a much smaller uncertainty. This article is protected by copyright. All rights reserved.
PubDate: 2015-04-01T15:19:24.165662-05:
DOI: 10.1002/aic.14818

• Delignification of intact biomass and cellulosic coproduct of
acid‐catalyzed hydrolysis
• Authors: Majid Soleimani; Lope G. Tabil, Catherine Niu
Abstract: The kinetics of acid‐catalyzed hemicellulose removal and also alkaline delignification of oat hull biomass were investigated. All three operational parameters namely, catalyst concentration (0.10–0.55 N H2SO4), temperature (110–130°C), and residence time (up to 150 min) affected the efficiency of hemicellulose removal, with 100% of hemicellulose removed by appropriate selection of process parameters. Analysis of delignification kinetics (in the temperature range of 30–100°C) indicated that it can be expressed very well by a two‐phase model for the crude biomass and also for the hemicellulose‐prehydrolyzed material. The application of acid‐catalyzed prehydrolysis improved the capacity of lignin dissolution especially at lower temperatures (30 and 65°C) and accelerated the dissolution of lignin. This acceleration of delignification by prehydrolysis was possible at all levels of temperature in the bulk phase; however, results were more significant at the lower temperatures in the terminal phase. © 2015 American Institute of Chemical Engineers AIChE J, 2015
PubDate: 2015-04-01T08:53:25.220682-05:
DOI: 10.1002/aic.14794

• Numerical study of laminar core‐annular flow in a torus and in a
90° pipe bend
• Authors: Gijs Ooms; Mathieu J. B. M. Pourquie, Jerry Westerweel
Abstract: A numerical study has been made of laminar core‐annular through a torus. It is a follow‐up of the study by Picardo and Pushpavanam, AIChE J. 2013;59(12):4871–4886, who obtained an analytical solution for the case that the core is concentric and circular. In our study, we investigated the possibility of eccentric core‐annular flow and the deformation of the core‐annular interface. We found that a stable eccentric core position is possible, which is shifted in the direction of the inner or outer side of the torus depending on the balance of the normal stresses at the core‐annular interface. When these stresses are too far off from those for concentric and circular core‐annular flow, fouling of the wall occurs. We compared the results of core‐annular flow in a torus with those for a 90° pipe bend and found that the flow pattern in the torus is representative for the flow pattern in the bend. © 2015 American Institute of Chemical Engineers AIChE J, 2015
PubDate: 2015-03-31T11:13:57.672037-05:
DOI: 10.1002/aic.14796

• A consecutive microreactor system for the synthesis of caprolactam with
high selectivity
• Authors: Kai Wang; Jisong Zhang, Chen Zheng, Chen Dong, Yangcheng Lu, Guangsheng Luo
Abstract: A microreactor system containing two consecutive microreactors and a stirred vessel was developed for the improvement of selectivity of caprolactam (CPL) synthesis. The first microreactor was used to conduct the reaction of cyclohexanecarboxylic acid and oleum, and 97% selectivity for the intermediate product, named mixed anhydride, was obtained. The mixed anhydride then quickly reacted with nitroso‐sulfuric acid in the second microreactor, and the reaction was completed in the vessel, where CPL selectivity reached 93.9%, a much higher value than that achieved either in a control experiment with a batch reactor or in industrial process. The advantage of microreactors is that they can provide high‐quality mixed anhydride and can mix it quickly with the nitroso‐sulfuric acid prior to reaction in the vessel reactor, which, from an engineering standpoint, gives better performance than the traditional syringe‐fed method that is common in chemical synthesis. © 2015 American Institute of Chemical Engineers AIChE J, 2015
PubDate: 2015-03-31T11:13:31.418275-05:
DOI: 10.1002/aic.14797

• The Future of the Lecture
• Authors: E. L. Cussler
PubDate: 2015-03-31T09:21:47.131094-05:
DOI: 10.1002/aic.14807

• Pore‐size evaluation and gas transport behaviors of microporous
membranes: An experimental and theoretical study
• Authors: Gang Li; Hye Ryeon Lee, Hiroki Nagasawa, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
Abstract: A modified gas‐translation (GT) model based on a GT mechanism was successfully applied to the pore‐size evaluation and gas transport‐behavior analysis of microporous membranes with different pore‐size distributions. Based on the gas permeation results of three microporous membranes derived from different alkoxides, the effects of activation energy and the selection of a standard gas on the pore‐size evaluation were discussed in a comparative study. The presence of nano‐sized defects had an important influence on the gas permeation performance of microporous membranes, depending largely on the original pore size of the membrane in question. Moreover, the gas‐separation effect of the pore‐size distribution in a silica membrane was theoretically studied, and revealed a significant increase in gas permeance for relatively large gas species but not for small ones. This article is protected by copyright. All rights reserved.
PubDate: 2015-03-30T17:39:19.505342-05:
DOI: 10.1002/aic.14812

• A compact photomicroreactor design for kinetic studies of gas‐liquid
photocatalytic transformations
• Authors: Yuanhai Su; Volker Hessel, Timothy Noël
PubDate: 2015-03-30T17:33:46.117974-05:
DOI: 10.1002/aic.14813

• Emulation of gas‐liquid flow in packed beds for offshore floating
applications using a swell simulation hexapod
• Authors: Gnouyaro P. Assima; Amir Motamed‐Dashliborun, Faïçal Larachi
Abstract: A laboratory‐scale packed column was positioned on a 6‐degree‐of‐freedom swell simulation hexapod to emulate the hydrodynamics of packed bed scrubbers/reactors onboard offshore floating systems. The bed was instrumented with wire mesh capacitance sensors to measure liquid saturation and velocity fields, flow regime transition, liquid maldistribution, and tracer radial and axial dispersion patterns while robot was subject to sinusoidal translation (sway, heave) and rotation (roll, roll + pitch, yaw) motions at different frequencies. Three metrics were defined to analyze the deviations induced by the various column motions, namely, coefficient of variation and degree of uniformity for liquid saturation fluctuating fields, and effective Péclet number. Non‐tilting oscillations led to frequency‐independent maldistribution while tilting motions induced swirl/zigzag secondary circulation and prompted non‐uniform maldistribution oscillations that deteriorated with decreasing frequencies. Regardless of excited degree of freedom, a qualitative loss of plug‐flow character was observed compared to static vertical beds which worsened as frequencies decreased. This article is protected by copyright. All rights reserved.
PubDate: 2015-03-30T17:31:09.083555-05:
DOI: 10.1002/aic.14816

• Multi‐objective optimization for designing and operating more
sustainable water management systems for a city in Mexico
• Authors: Ma. Guadalupe Rojas‐Torres; Gonzalo Guillén‐Gosálbez, Fabricio Nápoles‐Rivera, José María Ponce‐Ortega, Laureano Jiménez‐Esteller, Medardo Serna‐González
PubDate: 2015-03-30T17:30:12.812187-05:
DOI: 10.1002/aic.14814

• On‐line control of crystal properties in non‐isothermal
antisolvent crystallization
• Authors: Navid Ghadipasha; Jose A. Romagnoli, Stefania Tronci, Roberto Baratti
Abstract: This paper deals with the issues regarding the design and implementation of on‐line optimal control strategies of crystal properties in non‐isothermal antisolvent crystallization processes to control particles' mean size and standard deviation. The one‐dimensional Fokker‐Planck equation (FPE) is used to represent the dynamic characteristics of the crystal growth and generate iso‐mean and iso‐standard deviation curves. Using controllability tools it is demonstrated that the system is ill conditioned in the whole operational range, posing limitations on the achievable control performance. To circumvent the problem, a control strategy is formulated by pairing crystals' mean size with antisolvent feed rate and manipulating temperature to control the standard deviation. A novel digital image texturing analysis approach is discussed and implemented to track crystals' size distribution along the experiment and providing the on‐line information for further feedback control action. Subsequently, alternative control strategies are implemented and tested to achieve a desired crystal size distribution (CSD). This article is protected by copyright. All rights reserved.
PubDate: 2015-03-30T17:27:59.122586-05:
DOI: 10.1002/aic.14815

• Aldol condensation of n‐butyraldehyde in a biphasic stirred tank
reactor: Experiments and models
• Authors: Shinbeom Lee; Arvind Varma
Abstract: To model a biphasic stirred tank reactor, intrinsic reaction kinetics and interfacial area are required. In this study, reactor modeling for n‐butyraldehyde aldol condensation was investigated under industrially relevent conditions. The interfacial area in the reactor was directly measured using a borescope system under appropriate temperature, NaOH concentration and rpm conditions. To estimate the interfacial area, a semi‐empirical correlation was developed, which provides good estimates within ±15% error. The reactor model based on two‐film theory was developed, combining the interfacial area and intrinsic reaction kinetics reported in our prior work. The model was verified by reaction experiments in the range 0.05‐1.9M NaOH, 80‐130 oC and 600‐1000 rpm. The prediction errors using the interfacial area from direct measurements and the correlation were ±8% and ±15%, respectively, suggesting that the model accuracy may be improved with better interfacial area estimation. This article is protected by copyright. All rights reserved.
PubDate: 2015-03-30T17:25:03.729629-05:
DOI: 10.1002/aic.14817

• Modelling of a membrane reactor system for crude palm oil
transesterification. Part I: Chemical and phase equilibrium
• Authors: Pin Pin Oh; Mei Fong Chong, Harrison Lik Nang Lau, Junghui Chen, Yuen May Choo
Abstract: Using a membrane reactor for reversible transesterification reaction involves reaction and product separation within a single unit. However, a pseudo‐homogeneous reaction and heterogeneous separation must be maintained for successful membrane reactor operation. Present research is aimed to develop an integrated model of chemical and phase equilibrium (CPE) and modified Maxwell‐Stefan equation that describes the simultaneous CPE and mass transport phenomena of biodiesel production from crude palm oil (CPO) by using a membrane reactor. In the first part of this work, a systematic approach describing simultaneous CPE of CPO transesterification in the membrane reactor was developed with the reconciliation of transesterification reaction and phase equilibrium that involves six‐component. The results revealed that regressed apparent equilibrium constant, Keq value of 17.557±1.51% was higher than the literatures. This indicates that forward reaction of the reversible CPO transesterification is much favored in the membrane reactor than the conventional reactor. This article is protected by copyright. All rights reserved.
PubDate: 2015-03-27T00:19:34.541869-05:
DOI: 10.1002/aic.14806

• Developing intermolecular‐potential models for use with the
SAFT‐VR Mie Equation of State
• Authors: Simon Dufal; Thomas Lafitte, Amparo Galindo, George Jackson, Andrew J. Haslam
PubDate: 2015-03-27T00:19:08.693497-05:
DOI: 10.1002/aic.14808

• Investment optimization model for freshwater acquisition and wastewater
handling in shale gas production
• Authors: Linlin Yang; Meagan Mauter, Robert Dilmore, Ignacio E. Grossmann
PubDate: 2015-03-27T00:18:47.000691-05:
DOI: 10.1002/aic.14804

• Mesoscopic coarse‐grained simulations of hydrophobic charge
induction chromatography (HCIC) for protein purification
• Authors: Gaobo Yu; Jie Liu, Jian Zhou
PubDate: 2015-03-27T00:18:25.392627-05:
DOI: 10.1002/aic.14805

• A model‐based precipitation study of copper‐based catalysts
• Authors: Martin A. J. Hartig; Nikolas Jacobsen, Alexander Leuthold, Wolfgang Peukert
PubDate: 2015-03-27T00:13:56.500006-05:
DOI: 10.1002/aic.14810

• Solvent evaluation for desulfurization and denitrification of gas oil
using performance and industrial usability indices
• Authors: Sunil Kumar; Vimal Chandra Srivastava, S.M. Nanoti, Abhishek Kumar
Abstract: In this paper, a new strategy for screening of solvents for sulfur, nitrogen and aromatic compounds removal from gas oil is presented. This ranking is based on comparative assessment of solvents' capacity, selectivity, performance and newly defined industrial usability index. Twenty eight solvents comprising of six most widely used industrially proven conventional solvents and twenty two imidazolium based ionic liquids solvents were selected to illustrate the strategy. The solvents were ranked for removal of benzothiophene, dibenzothiophene and their alkylated derivatives sulfur compounds, quinoline, indole and carbazole nitrogen compounds from gas oil. Performance index (PI) which combines the effect of both capacity and selectivity seems to be better index than individual capacity and selectivity indexes to rank the solvents. Industrial usability index (SIUI) of solvents which includes PI and process complexity factor of solvent recovery seems more practical and realistic criteria to be used for solvents assessment for a given separation. This article is protected by copyright. All rights reserved.
PubDate: 2015-03-27T00:13:36.150343-05:
DOI: 10.1002/aic.14809

• Rigorous design of distillation columns using surrogate models based on
kriging interpolation
• Authors: Natalia Quirante; Juan Javaloyes, José A. Caballero
PubDate: 2015-03-21T09:25:13.669651-05:
DOI: 10.1002/aic.14798

• Thermodynamic mechanism of free heme action on sickle cell hemoglobin
polymerization
• Authors: Anupam Aich; Weichun Pan, Peter G. Vekilov
PubDate: 2015-03-21T09:25:12.125809-05:
DOI: 10.1002/aic.14800

• Modeling the permittivity of electrolyte solutions
• Authors: Jørgen M. Mollerup; Martin P. Breil
Abstract: Solution of a strong electrolyte in a high‐density polar fluid gives rise to a dielectric saturation that decreases the orientation polarizability of the solvent molecules in close proximity to the ions wherefore the relative permittivity in this region is determined solely by the atomic and electronic polarization. This causes a substantial decrease in the static permittivity of the solution. By considering the dielectric saturation, we have developed a model for the permittivity of an electrolyte solution and determined the parameters, the relative permittivities at dielectric saturation in close proximity to the ions, for 17 ions in water at 298.15K. By scaling these relative permittivities in proportion to the permittivity of the solvent, we were able to extend the model to calculate the permittivity of solutions of electrolytes in methanol and admixtures of water and ethanol. This article is protected by copyright. All rights reserved.
PubDate: 2015-03-21T09:25:10.682099-05:
DOI: 10.1002/aic.14799

• Multiscale modeling of oil uptake in fried products
• Authors: Jean‐Michaël Vauvre; Anna Patsioura, Régis Kesteloot, Olivier Vitrac
Abstract: Oil‐air biphasic flow has been simulated at the scale of an entire potato tuber tissue using a Kinetic Monte‐Carlo (KMC) formulation parameterized on microscopic observations. Extrapolations to more general configurations are proposed by combining the proposed KMC framework with oil momentum equations integrated at microscopic scale. Branched percolation routes in 3D honeycomb arrangement of cells are explored using a first‐passage algorithm. Three major applications are presented. KMC simulations are first considered to homogenize sparse dynamic observations at the scale of isolated cells up to the scale of a full tissue. The second application investigates the effect of cell damages on oil uptake. Finally, our general KMC formulation was successfully compared with a diffusive model of oil uptake. Comprehensive rules to set the distribution parameters of all quantities (kinetic and structure parameters) from scarce observations or general assumptions are discussed. This article is protected by copyright. All rights reserved.
PubDate: 2015-03-21T09:12:35.302834-05:
DOI: 10.1002/aic.14801

• Liquid li structure and dynamics: A comparison between OFDFT and second
nearest‐neighbor embedded‐atom method
• Authors: Mohan Chen; Joseph R. Vella, Frank H. Stillinger, Emily A. Carter, Athanassios Z. Panagiotopoulos, Pablo G. Debenedetti
PubDate: 2015-03-21T09:12:32.212563-05:
DOI: 10.1002/aic.14795

• Issue information
• Abstract: Top: Layerby‐layer coated nanoparticles designed for dual drug delivery imaged with cryo‐transmission electron microscopy (cryo‐TEM image taken by Erik Dreaden with assistance from Dr. Yun, MIT Koch Institute). Bottom: A degradable PLGA phase inversion membrane with top surface coated with a layer‐by‐layer film containing growth factors to promote bone formation (SEM image taken by Nisarg Shah and Nasim Hyder). 10.1002/aic.14770
PubDate: 2015-03-18T13:44:18.218456-05:
DOI: 10.1002/aic.14583

• An old kinetic method for a new polymerization mechanism: Toward
photochemically mediated ATRP
• Authors: Yin‐Ning Zhou; Zheng‐Hong Luo
PubDate: 2015-03-13T03:22:25.299832-05:
DOI: 10.1002/aic.14792

• Designing of anion‐functionalized ionic liquids for efficient
capture of SO2 from flue gas
• Authors: Kaihong Chen; Wenjun Lin, Xini Yu, Xiaoyan Luo, Fang Ding, Xi He, Haoran Li, Congmin Wang
Abstract: Five kinds of anion‐functionalized ionic liquids with different basicity and substituent were selected, prepared and applied in the capture of SO2 from flue gas, where the concentration of SO2 is only 2000 ppm. The effect of the anion on SO2 absorption capacity, desorption residue, and available absorption capacity under 2000 ppm was investigated. The relationship between available absorption capacity and absorption enthalpy was also studied. Through a combination of thermodynamic analysis and quantum calculation, the results indicated that the effect of the cation in the ionic liquid on absorption enthalpy was significant. However, the effect of chain length in the cation was weak. Hence, a new ionic liquid with low molecular weight, [P4442][Tetz], was further designed and applied for the capture of SO2, which shows the high absorption capacity of 0.18g SO2 per g ionic liquid and excellent reversibility for 2000 ppm SO2. This article is protected by copyright. All rights reserved.
PubDate: 2015-03-13T02:29:15.571995-05:
DOI: 10.1002/aic.14793

• Experimental and linear analysis for the instability of
non‐newtonian liquid jets issuing from a pressurized vibrating
nozzle
• Authors: C. Rodríguez‐Rivero; E.M.M. Del Valle, M.A. Galán
Abstract: We analyze experimentally and theoretically the laminar capillary breakup of viscoelastic jets to produce polymeric microcapsules. The phenomenon is based on subjecting a capillary jet to controlled disturbances so that it eventually breaks up forming individual droplets. We obtain a dispersion relation from a temporal linear analysis to describe and predict the system behavior that includes the Oldroyd‐B constitutive equation to take into account the viscoelasticity of the liquid. Dispersion curves relating growth rate and wavenumber of the perturbed jets are compared with experimental conditions and we found that the chosen mathematical approach fairly describes the system. The obtained dispersion relation eases the study of the effect of viscosity, elasticity ‐ through relaxation times ‐ and flow rate in the system. We conclude that the approach allows finding the best conditions to obtain homogeneous droplets and describe qualitatively the system. This article is protected by copyright. All rights reserved.
PubDate: 2015-03-13T02:28:55.810412-05:
DOI: 10.1002/aic.14790

• Thermodynamic and kinetic studies of the
MgCl2‐NH4Cl‐NH3‐H2O system for the production of high
purity MgO from calcined low grade magnesite
• Authors: Junfeng Wang; Ah‐Hyung Alissa Park, Camille Petit, Zhibao Li
PubDate: 2015-03-13T02:28:35.833408-05:
DOI: 10.1002/aic.14789

• A Model for gas transport in micro fractures of shale and tight gas
reservoirs
• Authors: Keliu Wu; Xiangfang Li, Chenchen Wang, Wei Yu, Zhangxin Chen
Abstract: A model for gas transport in micro fractures of shale and tight gas reservoirs is established. Slip flow and Knudsen diffusion are coupled together to describe general gas transport mechanisms, which include continuous flow, slip flow, transitional flow and Knudsen diffusion. The ratios of the intermolecular collision frequency and the molecule‐wall collision frequency to the total collision frequency are defined as the weight coefficients of slip flow and Knudsen diffusion, respectively. The model is validated by molecular simulation results. The results show that: (1) the model can reasonably describe the process of the mass transform of different gas transport mechanisms; (2) fracture geometry significantly impacts gas transport. Under the same fracture aperture, the higher the aspect ratio is, the stronger the gas transport capacity, and this phenomenon is more pronounced in the cases with higher gas pressure and larger fracture aperture. This article is protected by copyright. All rights reserved.
PubDate: 2015-03-13T02:28:17.000011-05:
DOI: 10.1002/aic.14791

• Intensification of convective heat transfer in a
stator‐rotor‐stator spinning disc reactor
• Authors: M.M. de Beer; J.T.F. Keurentjes, J.C. Schouten, J. van der Schaaf
PubDate: 2015-03-13T02:27:27.582864-05:
DOI: 10.1002/aic.14788

• Biofuel purification in GME zeolitic–imidazolate frameworks: From ab
initio calculations to molecular simulations
• Authors: Kang Zhang; Krishna M. Gupta, Yifei Chen, Jianwen Jiang
PubDate: 2015-03-06T18:13:25.542039-05:
DOI: 10.1002/aic.14787

• Thermodynamic and kinetic studies on alkoxylation of camphene over cation
exchange resin catalysts
• Authors: Huiqin Nie; Gaodong Yang, Ruyin Xu, Feng Zhang, Zheng Zhou, Zhibing Zhang
Abstract: The alkoxylation of camphene with 2‐methyl‐1,3‐propanediol was studied using anhydrous macroporous and strong acid cation exchange resins as catalysts. The effects of various parameters, such as catalyst type, solvent, molar ratio of reactants, reaction temperature and reusability of catalysts, were investigated in a 250mL stirred tank reactor to optimize the reaction conditions. The UNIFAC group contribution method was used to correct liquid nonideality, giving the thermodynamic equilibrium constant at 333‐370K. The enthalpy changes calculated by three different methods (Gaussian 03, constant, a function of temperature) were compared. The value (‐74.63.3 kJ/mol) calculated by the last method was closer to the theoretical value (‐75.73 kJ/mol) than that given by the second method (‐30.21.2 kJ/mol). A Langmuir‐Hinshelwood‐Hougen‐Watson (LHHW) model based on activity was used to fit experimental data and the activation energy was 29.14 kJ/mol. The optimized reaction conditions were also verified in a 5L reaction kettle. This article is protected by copyright. All rights reserved.
PubDate: 2015-03-06T18:01:47.969474-05:
DOI: 10.1002/aic.14786

• An optimal planning for the reuse of municipal solid waste considering
economic, environmental and safety objectives
• Authors: José Ezequiel Santibañez‐Aguilar; Juan Martínez‐Gómez, José María Ponce‐Ortega, Fabricio Nápoles‐Rivera, J. Betzabe González‐Campos, Medardo Serna‐González, Mahmoud M. El‐Halwagi
PubDate: 2015-03-04T12:01:18.333035-05:
DOI: 10.1002/aic.14785

• Adaptive model predictive inventory controller for multiproduct batch
plant
• Authors: Gyeongbeom Yi; Gintaras V. Reklaitis
PubDate: 2015-02-28T03:39:12.715973-05:
DOI: 10.1002/aic.14783

• Model‐based analysis of a gas/vapor‐liquid micro‐channel
membrane contactor
• Authors: A. Lautenschleger; A. Voigt, K. Sundmacher, E. Y. Kenig
Abstract: A comprehensive numerical investigation on membrane distillation of methanol and water in a micro‐separator was carried out. The focus was to investigate the impact of the apparatus geometry on the separation performance and to develop alternative designs for process intensification. To describe the process, a CFD‐based model was developed and validated against experimental data from literature. Based on this model, parametric studies were performed to gain a deeper understanding of the microchannel geometry influence. Furthermore, two geometry modifications were suggested and analysed, a miniaturisation of the channel and an implementation of baffles. The modification with baffles was chosen for a new separator design which was studied experimentally, and the obtained experimental data were used for another model validation, this time for the baffle arrangement. A subsequent comprehensive simulations were performed to investigate mass transfer enhancement by the modified geometry. Generally, the baffles revealed a considerable potential for the process intensification. This article is protected by copyright. All rights reserved.
PubDate: 2015-02-28T02:56:45.277685-05:
DOI: 10.1002/aic.14784

• Design and screening of ionic liquids for C2H2/C2H4 separation by
COSMO‐RS and experiments
• Authors: Xu Zhao; Qiwei Yang, Dan Xu, Zongbi Bao, Yi Zhang, Baogen Su, Qilong Ren, Huabin Xing
Abstract: Ionic liquids (ILs) have been proposed as promising solvents for separating C2H2 and C2H4, but screening an industrially attractive IL with high capacity from numerous available ILs remains challenging. In this work, a rapid screening method based on COSMO‐RS was developed. We also present an efficient strategy to improve the C2H2 capacity in ILs together with adequate C2H2/C2H4 selectivity with the aid of COSMO‐RS. The essence of this strategy is to increase molecular free volume of ILs and simultaneously enhance hydrogen‐bond basicity of anions by introducing flexible and highly asymmetric structures, which is validated by a new class of tetraalkylphosphonium ILs featuring long‐chain carboxylate anions. At 298.1K and 1 bar, the solubility of C2H2 in ILs reaches 0.476 mole per mole IL, very high for a physical absorption, with a selectivity of up to 21.4. The separation performance of tetraalkylphosphonium ILs to the mixture of C2H2/C2H4 was also evaluated. This article is protected by copyright. All rights reserved.
PubDate: 2015-02-27T01:51:20.509619-05:
DOI: 10.1002/aic.14782

• Shear‐rate‐dependent rheology effects on mass transport and
surface reactions in biomicrofluidic devices
PubDate: 2015-02-27T01:50:37.000629-05:
DOI: 10.1002/aic.14781

• Evaporation of pinned droplets containing polymer ‐ an examination
of the important groups controlling final shape
• Authors: Adam D. Eales; Nick Dartnell, Simon Goddard, Alexander F. Routh
Abstract: Controlling the final shape resulting from evaporation of pinned droplets containing polymer, is important in the fabrication of P‐OLED displays by inkjet printing. Typically a coffee‐ring shape arises, due to the pinning and associated outward capillary flow. For operational reasons, this is undesirable ‐ a flat topography is required. We wish to understand the important groups governing the shape, to provide a practical guide to ink selection. The theory presented is based on a thin‐film lubrication model. We solve the governing equations numerically and continuously track the lateral progression of a liquid/gel front. A large capillary number or large ratio of initial to maximal polymer volume fraction can suppress the coffee‐ring. White light interferometry is used to confirm these findings experimentally. This article is protected by copyright. All rights reserved.
PubDate: 2015-02-25T03:43:02.757351-05:
DOI: 10.1002/aic.14777

• Gas absorption into a wavy two‐layer falling film
• Authors: G. Çekiç; G. M. Sisoev
PubDate: 2015-02-25T03:42:43.53357-05:0
DOI: 10.1002/aic.14778

• Anatomy of a rapid pressure swing adsorption (RPSA) process performance
• Authors: Vemula Rama Rao; Mayuresh V. Kothare, Shivaji Sircar
PubDate: 2015-02-24T18:56:33.028039-05:
DOI: 10.1002/aic.14779

• A CO2‐stable hollow‐fiber membrane with high hydrogen
permeation flux
• Authors: Yan Chen; Yanying Wei, Qing Liao, Zhong Li, Armin Feldhoff, Juergen Caro, Haihui Wang
Abstract: A Mo‐substituted lanthanum tungstate mixed proton‐electron conductor, La5.5W0.6Mo0.4O11.25‐δ (LWM04), was synthesized using solid state reactions. Dense U‐shaped LWM04 hollow‐fiber membranes were successfully prepared using wet‐spinning phase‐inversion and sintering. The stability of LWM04 in a CO2‐containing atmosphere and the permeation of hydrogen through the LWM04 hollow‐fiber membrane were investigated in detail. A high hydrogen permeation flux of 1.36 ml/min·cm2 was obtained for the U‐shaped LWM04 hollow‐fiber membranes at 975 °C when a mixture of 80% H2‐20% He was used as the feed gas and the sweep side was humidified. Moreover, the hydrogen permeation flux did not significantly decrease over 70 h of operation when fed with a mixture containing 25% CO2, 50% H2, and 25% He, indicating that the LWM04 hollow‐fiber membrane has good stability under a CO2‐containing atmosphere. This article is protected by copyright. All rights reserved.
PubDate: 2015-02-24T06:00:55.500767-05:
DOI: 10.1002/aic.14772

• Mathematical modeling of polyethylene terephthalate (PET) pyrolysis in a
spouted bed
• Authors: Arezou Niksiar; Amir Hasan Faramarzi, Morteza Sohrabi
Abstract: A model has been developed for pyrolysis of PET in a spouted bed reactor based on the conservation equations for heat, mass, and momentum transports. A spouted bed has been constructed and the kinetic parameters have been obtained within the temperature range of 723‐833 K, using two particle size ranges, (0.1‐1.0)×10‐3 and (1.0‐3.0)×10‐3 m. The model’ predictions for the radial distributions of temperature and concentration confirm the excellent mixing of particles. Thus, spouted beds are appropriate equipments for performing kinetic studies of PET pyrolysis. The inlet gas temperature and the mass of PET highly affect PET conversion. The amount of inert particles has a negligible effect on the conversion and it can be reduced as far as a stable spouting is preserved. The gas flow suffices to eliminate the external heat and mass transfer limitations. It can be reduced to the minimum value in order to decrease the energy consumption. This article is protected by copyright. All rights reserved.
PubDate: 2015-02-23T18:47:18.747821-05:
DOI: 10.1002/aic.14775

• “Perspective: AIChE 2014 alpha chi sigma award”
• Authors: Paula T. Hammond; David H. Koch
PubDate: 2015-02-22T23:47:30.419326-05:
DOI: 10.1002/aic.14770

• Practical improvements to autocovariance least‐squares
• Authors: Megan A. Zagrobelny; James B. Rawlings
Abstract: Identifying disturbance covariances from data is a critical step in estimator design and controller performance monitoring. We examine here the autocovariance least‐squares (ALS) method for this identification. For large industrial models with poorly observable states, the process noise covariance is high dimensional and the optimization problem is poorly conditioned. Also, weighting the least‐squares problem with the identity matrix does not provide minimum variance estimates. Here we modify ALS method to resolve these two challenges. We identify and remove poorly observable states using the SVD of the observability matrix, thus decreasing the computational time. Using a new feasible generalized least‐squares estimator that approximates the optimal weighting from data, we significantly reduce the variance of the estimates. We successfully demonstrate the new approach on industrial data sets provided by Praxair. The disturbance model identified by the ALS method produces an estimator that performs optimally over a year‐long period. This article is protected by copyright. All rights reserved.
PubDate: 2015-02-22T23:46:57.965434-05:
DOI: 10.1002/aic.14771

• Freeze‐drying of initially unsaturated material frozen with
pre‐built pores
• Authors: Wei Wang; Dapeng Hu, Yanqiu Pan, Yanqiang Zhao, Guohua Chen
PubDate: 2015-02-17T16:06:45.317032-05:
DOI: 10.1002/aic.14769

• DEM‐CFD modelling of particle systems with long‐range
electrostatic interactions
• Authors: Chunlei Pei; Chuan‐Yu Wu, David England, Stephen Byard, Harald Berchtold, Michael Adams
Abstract: To investigate dynamic behaviours of mono‐charged particle systems, a direct truncation (DT) method and a hybrid particle‐cell (HPC) method are implemented into the discrete element method coupled with computational fluid dynamics (DEM‐CFD) with defined cut‐off distances. The DT method only considers electrostatic interactions between particles within the cut‐off distance while the HPC method computes electrostatic interactions in the entire computational domain. The deposition process of mono‐charged particles in a container in air was simulated using the developed DEM‐CFD. It was found that, using DT method, the macrostructure, evolution of granular temperature and radial distribution function of the particle system are sensitive to the specified cut‐off distance. In contrast, using HPC method, these results were independent of the specified cut‐off distance, as expected. This implies that, although electrostatic interactions between particles with large separation distances are weak, they should be considered in DEM‐CFD for accurate modelling of charged particle systems. This article is protected by copyright. All rights reserved.
PubDate: 2015-02-16T02:29:37.106827-05:
DOI: 10.1002/aic.14768

• The Role of Wall Deposition and Re‐Entrainment in Swirl Spray Dryers
• Authors: Víctor Francia; Luis Martín, Andrew E. Bayly, Mark J.H. Simmons
PubDate: 2015-02-16T01:47:19.525483-05:
DOI: 10.1002/aic.14767

• Multistream Heat Exchangers: Equation‐Oriented Modeling and
Flowsheet Optimization
• Authors: Richard C. Pattison; Michael Baldea
PubDate: 2015-02-16T01:06:59.127739-05:
DOI: 10.1002/aic.14766

• John M. Prausnitz: Bridging abstractions and realities
• Authors: John P. O'Connell
PubDate: 2015-02-12T19:13:32.180393-05:
DOI: 10.1002/aic.14761

• Suspending a Solid Sphere in Laminar Inertial Liquid Flow –
Experiments and Simulations
• Authors: Junyuan Mo; Zhengming Gao, Zhipeng Li, Yuyun Bao, J.J. Derksen
Abstract: The critical conditions for the suspension of single, spherical solid particles by a liquid flow in a square container driven by a rotating disk have been determined. In the experiments, the motion of the sphere has been visualized quantitatively. The conditions are such that the flow in the container is laminar (Reynolds numbers based on the rotating disk characteristics are in the range 10 – 40). The Archimedes numbers of the spheres are of order 1. The suspension process has also been numerically simulated with full resolution of the liquid flow, including the flow around the sphere, and the translational and rotational motion of the sphere. The simulations recover the critical conditions to within 3% in terms of the rotational speed of the disk. Also the sphere's trajectory in the container is reproduced well by the simulations. This article is protected by copyright. All rights reserved.
PubDate: 2015-02-06T02:45:29.967645-05:
DOI: 10.1002/aic.14756

• Catalytic hydrothermal liquefaction of D. tertiolecta for the production
of bio‐oil over different Acid/base catalysts
• Authors: Yu Chen; Yulong Wu, Ranran Ding, Pan Zhang, Ji Liu, Mingde Yang
Abstract: In this paper, two acid catalysts (ZrO2/SO42‐ and HZSM‐5) and two base catalysts (MgO/MCM‐41 and KtB) were employed in catalytic hydrothermal liquefaction (HTL) of D. tertiolecta for the production of bio‐oil. The results indicated that the acid/base property of the catalyst plays a crucial role in the catalytic HTL process, and the base catalyst is conducive to the improvement of conversion and bio‐oil yield. When KtB was used as the catalyst, the maximum conversion and bio‐oil yield was 94.84 and 49.09 wt.%, respectively. The detailed compositional analysis of the bio‐oil was performed using TGA, EA, FT‐IR, and GC‐MS. The compositional analysis results showed that the introduction of catalyst is beneficial for reducing the fixed carbon content in the bio‐oil, and the structure of catalyst influences on the bio‐oil composition and boiling point distribution. Based on our results and previous studies, the probable catalytic HTL microalgae model over various catalysts can be described that the main chemical reactions include ketonization, decarboxylic, dehydration, ammonolysis, etc. with HZSM‐5 and MgO/MCM‐41 as the catalyst; the cyclodimerization, decomposition, Maillard reaction and ketonization are the main reactions with ZrO2/SO42‐ as the catalyst; the dehydration, ammonolysis, Maillard reaction and ketonization can occur with KtB as the catalyst. Therefore, a plausible reaction mechanism of the main chemical component in D. tertiolecta is proposed. This article is protected by copyright. All rights reserved.
PubDate: 2015-01-30T02:41:42.587022-05:
DOI: 10.1002/aic.14740

• Mean Drop Size Correlations and Population Balance Models for Liquid
– Liquid Dispersion
• Authors: Mohd Izzudin Izzat Zainal Abidin; Abdul Aziz Abdul Raman, Mohamad Iskandr Mohamad Nor
Abstract: Reliable models are required for accurate estimation of drop sizes which govern the interfacial area and rate of mass transfer in a system where various correlations and models have been improved for better accuracy and wider application breath. In this paper, relevant semiempirical equations and population balance equation models are reviewed. Semi‐empirical correlations are highly system dependent and limited to prediction of steady‐state drop size while population balance equation models could estimate transient drop size with considerations of inhomogeineity and flow spatial variation during drop size evolution. With appropriate model parameters determination, different population balance equation models can be used to reproduce experimental data for a similar system. This article is protected by copyright. All rights reserved.
PubDate: 2015-01-29T06:04:26.175193-05:
DOI: 10.1002/aic.14751

• Ammonia synthesis enhanced by magnesium chloride absorption
• Authors: Heath H. Himstedt; Mark S. Huberty, Alon V. McCormick, Lanny D. Schmidt, E. L. Cussler
Abstract: Conversion to ammonia with Haber–Bosch catalysts can be increased above 95% by selective absorption of ammonia by MgCl2. The maximum conversion depends on reaction and absorption equilibria. At very short times, the measured conversion rate is the same with and without absorption by the MgCl2 salt; the overall rate constants are comparable to those in the literature. At larger times, conversion to ammonia can be over seven times greater with MgCl2 than without. However, the overall rate constants can be over 10 times slower because they are controlled by ammonia diffusion in the solid salt. An approximate, pseudosteady state theory consistent with these results provides a strategy for improving the overall rate while keeping the conversion over 90%. For example, the absorption rates might be increased using smaller particles of absorbent on a porous inert absorbent support. The results provide part of the basis for designing small scale ammonia plants. © 2015 American Institute of Chemical Engineers AIChE J, 2015
PubDate: 2015-01-27T12:57:42.884983-05:
DOI: 10.1002/aic.14733

• Moving ion fronts in mixed ionic‐electronic conducting polymer films
• Authors: Sarah E. Feicht; George D. Degen, Aditya S. Khair
PubDate: 2015-01-22T16:06:32.513578-05:
DOI: 10.1002/aic.14746

• Crystallization of Selective Polymorph Using Relationship between
Supersaturation and Solubility
• Authors: Kwang‐Joo Kim; Michael F. Doherty
Abstract: For polymorph screening, the plot of ΔCmet/Cc against C*/Cc in nucleation kinetics was investigated. The polymorph screening for forms I and II, and amorphous form of clopidogrel hydrogen sulfate (CHS) was carried out according to the nucleation kinetics expressed by this plot. The stability order of polymorphs for famotidin were also predicted successfully by this model. This model was used in the expectation of supersaturation level for polymorphic formation. Two types of polymorphic crystallization; transformation from metastable form to stable form, and nucleation and growth of polymorphic form without trnsformation can be explained. Amorphous form was also expected by this model. Even though polymorphs depend on lots of crystallization parameters such as solvent, temperature, concentration, cooling rate, etc., plot of ΔCmet/Cc and the C*/Cc in various nucleation kinetics gives a guide line for screening of polymorph. This article is protected by copyright. All rights reserved.
PubDate: 2015-01-22T09:45:32.615941-05:
DOI: 10.1002/aic.14745

• Microscopic imaging of biphasic oil‐air flow in french fries using
• Authors: Anna Patsioura; Jean‐Michaël Vauvre, Régis Kesteloot, Frédéric Jamme, Pamela Hume, Olivier Vitrac
PubDate: 2015-01-19T17:48:29.160882-05:
DOI: 10.1002/aic.14744

• Experimental study of hydrodynamics and thermal behavior of a
pseudo‐2D spout‐fluidized bed with liquid injection
• Authors: Vinayak S. Sutkar; Niels G. Deen, Amit V. Patil, Elias A.J.F. Peters, J.A.M. Kuipers, Vitalij Salikov, Sergiy Antonyuk, Stefan Heinrich
Abstract: A novel nonintrusive technique is presented to investigate hydrodynamic and thermal behavior of gas–solid spout‐fluidized beds with liquid injection, by simultaneously capturing visual and infrared images. Experiments were performed in a pseudo‐2D bed with draft plates filled with glass or γ‐alumina particles to investigate the effect of liquid injection and particle properties on the flow characteristics. For the glass particles under dry and wet conditions, time‐averaged particle velocities show similar quasi‐steady‐state behavior. However, under wet conditions, lower particle velocities were observed in both spout and annulus as compared with the dry system. Whereas, γ‐alumina particles do not show considerable variation in the particle velocities under dry and wet conditions and fluidize well at higher liquid injection rates. Additionally, for the glass particles, the particle temperature significantly decreases as compared to the γ‐alumina particles. © 2014 American Institute of Chemical Engineers AIChE J, 2014
PubDate: 2015-01-10T20:46:53.201407-05:
DOI: 10.1002/aic.14719

• Modelling and simulation of an industrial‐scale parex process
• Authors: Marta S. P. Silva; José P. B. Mota, Alírio E. Rodrigues
PubDate: 2015-01-08T17:08:04.014638-05:
DOI: 10.1002/aic.14732

• On the use of the generalized autocatalytic models: The thermal
decomposition of 3,5‐dinitro‐4‐methylbenzoic Acid
• Authors: Roberto Sanchirico
Abstract: The thermal decomposition of 3,5‐dinitro‐4‐methylbenzoic acid is studied by means of differential calorimetric techniques (DSC). Its autocatalytic behaviour has been highlighted and the decomposition process has been described considering the generalized expression of the Šesták‐Berggren model. A new procedure for the optimization of the initiation parameter along with the other Arrhenius and kinetic exponents starting from the knowledge of the classic Šesták‐Berggren model is illustrated. Encouraging results point out the validity of the approach which has been verified considering both a series of numerical and real experiments. This article is protected by copyright. All rights reserved.
PubDate: 2015-01-05T15:11:12.094277-05:
DOI: 10.1002/aic.14729

• Removal of Hg0 from flue gas using two homogeneous
Photo‐Fenton‐Like reactions
• Authors: Yangxian Liu; Jun Zhang, Yanshan Yin
Abstract: Removal of Hg0 using two homogeneous Photo‐Fenton‐Like reactions was firstly investigated in a photochemical reactor. Effects of process parameters on Hg0 removal were studied. Free radical and reaction products were analyzed. Removal pathways of Hg0 were discussed. Simultaneous removal of Hg0, NO and SO2 is also studied briefly. The results show that UV power, wavelength, H2O2 concentration and solution pH have great effects on Hg0 removal. Hg0 and SO2 concentrations, solution temperature, Fe3+, Cu2+, CO32‐ and HCO3‐ concentrations also have significant effects on Hg0 removal. However, concentrations of CO2, NO, O2, Cl‐, NO3‐, SO42‐, SiO2, Al2O3 and Fe2O3 only have slight effects on Hg0 removal. Hg0/NO/SO2 can be simultaneously removed by Photo‐Fenton‐Like reactions. ·OH was captured, and SO42‐/NO3‐/Hg2+ were also detected. Removals of Hg0 by photochemical oxidation and ·OH oxidation play a major role, and removal of Hg0 by H2O2 oxidation only plays a secondary role in removal of Hg0. This article is protected by copyright. All rights reserved.
PubDate: 2015-01-05T15:09:53.940271-05:
DOI: 10.1002/aic.14727

• Experimental investigation of electrostatic effect on bubble behaviors in
gas‐solid fluidized bed
• Authors: Kezeng Dong; Qing Zhang, Zhengliang Huang, Zuwei Liao, Jingdai Wang, Yongrong Yang
Abstract: Electrostatics and hydrodynamics in the fluidized bed are mutually affected, and excess accumulation of electrostatic charges has a severe impact on hydrodynamics. However, there is a serious lack of experimental investigation of electrostatic effect on hydrodynamics. This work provides a first insight into the electrostatic effects on bubble behaviors experimentally by injecting a trace of liquid antistatic agents (LAA) into a fluidized bed. Different amounts of LAA (0~50 ppm) were injected to make the electrostatic charges vary in a wide range and the bubble behaviors were investigated simultaneously. Results showed that the charges on particles decreased with increasing amount of LAA, which resulted in larger bubble sizes, stronger fluctuations of dynamic bed height and less wall sheeting, respectively. The maximum reduction ratio of bubble sizes due to electrostatic effect was 21%. When particles were charged, the bubble sizes were significantly smaller than those estimated from the classical correlation. This discrepancy was attributed to the neglect of electrostatic effect in classical correlation. This article is protected by copyright. All rights reserved.
PubDate: 2015-01-05T15:09:36.087657-05:
DOI: 10.1002/aic.14725

• A comparison of flow development in high density gas‐solids
circulating fluidized bed downer and riser reactors
• Authors: Chengxiu Wang; Chunyi Li, Shahzad Barghi, Jesse Zhu
Abstract: Comparison of flow development in high density downer and riser reactors is experimentally investigated using FCC particles with very high solids circulation rate up to 700 kg/m2s for the first time. Results show that both axial and radial flow structures are more uniform in downers compared to riser reactors even at very high density conditions, although the solids distribution becomes less uniform in the high density downer. Solids acceleration is much faster in the downer compared to the riser reactor indicating a shorter length of flow development and residence time, which is beneficial to the chemical reactions requiring short contact time and high product selectivity. Slip velocity in risers and downers is also firstly compared at high density conditions. The slip velocity in the downer is much smaller than in the riser for the same solids holdup indicating less particle aggregation and better gas‐solids contacting in the downer reactors. This article is protected by copyright. All rights reserved.
PubDate: 2015-01-05T15:09:18.728524-05:
DOI: 10.1002/aic.14728

• Semi‐analytical characterization of turbulence from radial
impellers, with experimental and numerical validation
• Authors: R. Ben‐Nun; B. Kysela, J. Konfršt, I. Fořt, M. Sheintuch
PubDate: 2014-12-30T13:29:34.732504-05:
DOI: 10.1002/aic.14723

• An analytical relationship of concentration dependent interfacial solute
distribution coefficient for aqueous layer freeze concentration
• Authors: Xiao Dong Chen; Ping Chen, Duo Wu
Abstract: Freeze concentration (FC) is a sub‐zero temperature solute concentration procedure, favoring the retention of high quality compounds such as food ingredients and biological materials. It is known that modeling solute inclusion in the ice layers or ice crystals formed in a convective environment requires the solute distribution coefficient function. The fluid flow velocity, ice‐growth rate and solute concentration are influential on this function. Some literature has reported certain expressions of the function, which are relatively complex. Here, an explicit format of this function has been derived for single solute system, and found to be satisfactory in correlating a wide range of experimental data on sucrose solutions for both the controlled flow layer crystallization process (flow in between two cooling plates) as well as the falling film crystallization process. This expression has captured the fundamental aspects of mass transfer and it is relatively simple which should be very useful for correlating FC parameters and for simulating the layer freeze concentration processes. This article is protected by copyright. All rights reserved.
PubDate: 2014-12-30T12:56:27.397096-05:
DOI: 10.1002/aic.14722

• Shear stability of inverse latexes during their polymerization process
• Authors: Stefano Lazzari; Baptiste Jaquet, Hua Wu, Massimo Morbidelli
Abstract: We study the shear‐stability of inverse latexes (IL) during their polymerization process. The IL is made of water droplets containing a copolymer of acrylamide and dimethyl‐aminoethyl‐methylenechloride emulsified in a paraffin oil. It is found for the first time that the shear stability of the ILs is a non‐monotonic function of the monomer conversion. At low conversions the shear stability increases as the conversion increases, but at a certain conversion value it reaches a local maximum and then decreases with conversion. Moreover, at the final stage of the conversion, the shear stability can increase again. A proper interpretation of this behavior is proposed and related to the combined effects of the polymer properties, fractal aggregation and coalescence. This article is protected by copyright. All rights reserved.
PubDate: 2014-12-30T12:21:41.307665-05:
DOI: 10.1002/aic.14721

• Synthesis and application of ethylenediamine tetrapropionic salt as a
novel draw solute for forward osmosis application
• Authors: Qingwu Long; Guangxian Qi, Yan Wang
Abstract: The development of suitable draw solutes for forward osmosis (FO) process is a big obstacle on the way of its real industrialization. In this work, a novel draw solute, ethylenediamine tetrapropionic (EDTP) acid (salt) is developed for FO application. The successful synthesis is confirmed by FTIR, NMR, and HRMS. By optimizing the pH of EDTP solution, its composition is varied and therefore its water solubility and osmotic pressure are effectively improved. The effects of EDTP concentration on the osmotic pressure and FO performance are also investigated. Its outstanding osmotic pressure and big molecular size result in a high water flux of 22.69 LMH and a low salt flux of 0.32 gMH with 0.8M EDTP draw solution (water as the feed solution, PRO mode). The good stability and easy recovery by nanofiltration of EDTP solution also demonstrate its great potential as the draw solute for future FO applications. This article is protected by copyright. All rights reserved.
PubDate: 2014-12-30T12:02:29.598703-05:
DOI: 10.1002/aic.14720

• Impact of the Diffusion Limitation in Microphotoreactors
• Authors: Tristan Aillet; Karine Loubière, Odile Dechy‐Cabaret, Laurent Prat
Abstract: This publication describes a model that aims (i) to predict the performances (conversion, photonic efficiency) of a photochemical reaction at the outlet of a microreactor. To achieve this, a set of equations that couple mass transport, radiative transfer and kinetic equations is established and solved, considering (i) a two dimensional geometry, and (ii) a simple monomolecular photoreaction , where the species A and B are in competition for absorbing incident photons. The model is expressed using classical dimensionless numbers, such as the Damköhler I and II numbers, the absorbance and the competitive absorption factor. The results show how and why, when competitive absorption exists, the occurrence of diffusion limitations ( DaII>1) can severely impact the conversion of the photochemical reaction and the photonic efficiency. Consequently, a diagram is proposed as a practical tool for selecting operating conditions subsequently avoiding these limitations. This article is protected by copyright. All rights reserved.
PubDate: 2014-12-22T04:58:33.537006-05:
DOI: 10.1002/aic.14718

• Analysis and Optimization of Pressure Retarded Osmosis for Power
Generation
• Authors: Mingheng Li
Abstract: This work focuses on model‐based analysis and optimization of pressure retarded osmosis (PRO) for power generation. The effects of membrane properties (hydraulic permeability, mass transfer characteristics), design conditions (inlet osmotic pressures, inlet flows and membrane area) and operating condition (applied pressure) on power density and efficiency are systematically investigated. A dimensionless design parameter , originally developed in analysis and optimization of reverse osmosis, is used to quantify the effect of dilution in draw solution as water permeates through membrane. An optimization method is developed to maximize PRO performance. It is shown that dilution and concentration polarization significantly reduce the maximum power density, and the optimal ΔP shifts away from Δπ0/2 Moreover, power density and efficiency follow opposite trends when varying process conditions including draw solution flow rate and membrane area. Enhancing membrane properties is crucial to improve the economic feasibility of PRO. This article is protected by copyright. All rights reserved.
PubDate: 2014-12-22T03:31:04.244934-05:
DOI: 10.1002/aic.14715

• Engineering Biomass into Formaldehyde‐free Phenolic Resin for
Composite Materials
• Authors: Yongsheng Zhang; Zhongshun Yuan, Chunbao (Charles) Xu
Abstract: The use of formaldehyde to prepare phenol‐formaldehyde (PF) resins is one of the primary challenges for the world‐wide PF industry with respect to both sustainability and human health. This study reports a novel one‐pot synthesis process for phenol‐5‐Hydroxymethylfurfural (PHMF) resin as a formaldehyde‐free phenolic resin using phenol and glucose, and the curing of the phenolic resin with a green curing agent organosolv lignin (OL) or Kraft lignin (KL). Evidenced by 13C NMR, the curing mechanism involves alkylation reaction between the hydoxyalkyl groups of lignin and the ortho‐ and para‐ carbon of PHMF phenolic hydroxyl group. The curing kinetics was studied using differential scanning calorimetry (DSC) and the kinetic parameters were obtained. The OL/KL cured PHMF resins were tested in terms of thermal stability, and mechanical properties for their applications in fiberglass reinforced composite materials. The results obtained demonstrated that OL/KL can be promising curing agents for the PHMF resins. This article is protected by copyright. All rights reserved.
PubDate: 2014-12-20T00:45:21.837433-05:
DOI: 10.1002/aic.14716

• Towards More Cost‐Effective and Greener Chemicals Production from
Shale Gas by Integrating with Bioethanol Dehydration: Novel Process Design
and simulation‐based Optimization
• Authors: Chang He; Fengqi You
Abstract: This paper presents a novel process design for a more cost‐effective, greener process for making chemicals from shale gas and bioethanol. The oxidative coupling of methane (OCM) and co‐cracking technologies are considered for converting methane and light natural gas liquids (NGLs), into value‐added chemicals. Overall, the process includes four process areas: gas treatment, gas to chemicals, methane‐to‐ethylene, and bioethanol‐to‐ethylene. We develop a simulation‐optimization method based on the NSGA‐II algorithm for the life cycle optimization (LCO) of the process modelled in the Aspen HYSYS. An energy integration model is also fluidly nested using the mixed‐integer linear programming. The results show that for a “good choice” optimal design, the minimum ethylene selling price is $655.1/ton and the unit global‐warming potential of ethylene is 0.030 kg CO2‐eq/kg in the low carbon shale gas scenario, and$877.2/ton and 0.360 kg CO2‐eq/kg in the high carbon shale gas scenario. This article is protected by copyright. All rights reserved.
PubDate: 2014-12-15T10:13:12.540377-05:
DOI: 10.1002/aic.14713

• Synthesis of C‐H‐O Symbiosis Networks
• Authors: Mohamed M. B. Noureldin; Mahmoud M. El‐Halwagi
Abstract: This paper introduces the concept of synthesizing carbon, hydrogen, and oxygen (C‐H‐O) SYmbiosis Networks (CHOSYNs) for the design of eco‐industrial parks (EIPs). Within a CHOSYN, compounds containing C‐H‐O are exchanged, converted, separated, mixed, and allocated. The use of C‐H‐O as the basis for integration creates numerous opportunities for synergism because C, H, and O are the primary building blocks for many industrial compounds that can be exchanged and integrated. A particularly attractive feature of the CHOSYN framework is its ability to use atomic‐based targets to establish benchmarks for the design of macroscopic systems involving multiple processes. Several structural representations, benchmarking, and optimization formulations are developed to embed potential CHOSYN configurations of interest and to synthesize cost‐effective networks. A case study with several scenarios is solved to demonstrate the new concept and tools. This article is protected by copyright. All rights reserved.
PubDate: 2014-12-15T10:12:51.415866-05:
DOI: 10.1002/aic.14714

• Multicomponent gas diffusion in non‐uniform tubes
• Authors: Thomas Veltzke; Lars Kiewidt, Jorg Thöming
Abstract: In many technical processes gas multicomponent diffusion takes place in confinements that are rarely uniform in direction of their long axis (e.g., catalysts pores). Here we show that in conical tubes multicomponent diffusion is hindered. This effect increases with ratio of inlet to outlet cone radius Λ, indifferent of the orientation of the tube. Based on the Maxwell‐Stefan equations we developed a predictive analytical solution for ideal multicomponent diffusion in slightly tapered ducts. In Two Bulb Diffusion Experiments on a uniform tube the results of Duncan and Toor (1962) were reproduced. Comparison of model and experiment shows that the solution presented here provides a reliable quantitative prediction of the temporal change of H2, N2, and CO2‐concentration for both tube geometries, uniform and slightly conical. In the demonstrated case (Λ = 3.16) mass diffusion is 68% delayed. Thus, for gaseous diffusion in “real”, typically tapered pores the transport limitation is more serious than considered so far. This article is protected by copyright. All rights reserved.
PubDate: 2014-12-12T03:10:22.574515-05:
DOI: 10.1002/aic.14711

• Optimal design and operations of water supply chain networks for shale gas
production: MILFP model and algorithms for the water‐energy nexus
• Authors: Jiyao Gao; Fengqi You
Abstract: The optimal design and operations of water supply chain networks for shale gas production is addressed. A mixed‐integer linear fractional programming (MILFP) model is developed with the objective to maximize profit per unit freshwater consumption, such that both economic performance and water‐use efficiency are optimized. The model simultaneously accounts for the design and operational decisions for freshwater source selection, multiple transportation modes, and water management options. Water management options include disposal, commercial centralized wastewater treatment (CWT), and onsite treatment (filtration, lime softening, thermal distillation). To globally optimize the resulting MILFP problem efficiently, three tailored solution algorithms are presented: a parametric approach, a reformulation‐linearization method, and a novel Branch‐and‐Bound & Charnes‐Cooper transformation method. The proposed models and algorithms are illustrated through two case studies based on Marcellus shale play, in which onsite treatment shows its superiority in improving freshwater conservancy, maintaining a stable water flow, and reducing transportation burden. This article is protected by copyright. All rights reserved.
PubDate: 2014-12-12T02:57:40.621741-05:
DOI: 10.1002/aic.14705

• Synthesis of butyl acrylate in a fixed‐bed adsorptive reactor over
Amberlyst 15
• Authors: Dânia S. M. Constantino; Carla S. M. Pereira, Rui P. V. Faria, Alexandre F. P. Ferreira, José M. Loureiro, Alírio. E. Rodrigues
Pages: 1263 - 1274
Abstract: The butyl acrylate synthesis from the esterification reaction of acrylic acid with 1‐butanol in a fixed‐bed adsorptive reactor packed with Amberlyst 15 ion exchange resin was evaluated. Adsorption experiments were carried out with nonreactive pairs at two temperatures (323 and 363 K). The experimental results were used to obtain multicomponent adsorption equilibrium isotherms of Langmuir type. Reactive adsorption experiments using different feed molar ratios and flow rates were performed, at 363 K, and used to validate a mathematical model developed to describe the dynamic behavior of the fixed‐bed adsorptive reactor for the butyl acrylate synthesis. Due to the simultaneous reaction and separation steps, it was possible to obtain a butyl acrylate maximum concentration 38% higher than the equilibrium concentration (for an equimolar reactants ratio solution as feed at a flow rate of 0.9 mL min−1 and 363 K) showing that sorption‐enhanced reaction technologies are very promising for butyl acrylate synthesis. © 2014 American Institute of Chemical Engineers AIChE J, 61: 1263–1274, 2015
PubDate: 2014-12-16T13:20:45.066853-05:
DOI: 10.1002/aic.14701

• Effects of flow history on oil entrapment in porous media: An experimental
study
• Authors: Homa Khosravian; Vahid Joekar‐Niasar, Nima Shokri
Pages: 1385 - 1390
Abstract: The effect of flow history on fluid phase entrapment during immiscible two‐phase flow in Hele‐Shaw cells packed with spherical and crushed glass beads is investigated. The wetting fluid is injected into an initially oil saturated cell at a well‐defined capillary number. It is observed that the size and shape of the trapped clusters strongly depend on the history of flooding such that less oil was trapped in the medium when the injecting capillary number gradually increased to the final maximum capillary number compared to the case when the injection was started and maintained constant at the maximum capillary number. In addition, a comprehensive series of experiments were conducted to delineate the effects of the capillary number on the phase entrapment. Contrary to previously published data, our experimental data reveal that the residual oil saturation depends on capillary number nonmonotonically. A physically based relationship to scale the capillary desaturation curve is proposed. © 2014 American Institute of Chemical Engineers AIChE J, 61: 1385–1390, 2015
PubDate: 2014-12-21T00:21:47.031921-05:
DOI: 10.1002/aic.14708

• A unified theoretical model for breakup of bubbles and droplets in
turbulent flows
• Authors: Chutian Xing; Tiefeng Wang, Kunyu Guo, Jinfu Wang
Pages: 1391 - 1403
Abstract: Pressure has a significant effect on bubble breakup, and bubbles and droplets have very different breakup behaviors. This work aimed to propose a unified breakup model for both bubbles and droplets including the effect of pressure. A mechanism analysis was made on the internal flow through the bubble/droplet neck in the breakup process, and a mathematical model was obtained based on the Young–Laplace and Bernoulli equations. The internal flow behavior strongly depended on the pressure or gas density, and based on this mechanism, a unified breakup model was proposed for both bubbles and droplets. For the first time, this unified breakup model gave good predictions of both the effect of pressure or gas density on the bubble breakup rate and the different daughter size distributions of bubbles and droplets. The effect of the mother bubble/droplet diameter, turbulent energy dissipation rate and surface tension on the breakup rate, and daughter bubble/droplet size distribution was discussed. This bubble breakup model can be further used in a population balance model (PBM) to study the effect of pressure on the bubble size distribution and in a computational fluid dynamics‐population balance model (CFD‐PBM) coupled model to study the hydrodynamic behaviors of a bubble column at elevated pressures. © 2014 American Institute of Chemical Engineers AIChE J, 61: 1391–1403, 2015
PubDate: 2014-12-21T00:23:46.212511-05:
DOI: 10.1002/aic.14709

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