AIChE Journal

Publisher: American Institute of Chemical Engineers, John Wiley and Sons

Description

The AIChE Journal is the premier research monthly in chemical engineering and related fields. This peer-reviewed and broad-based journal reports on the most important and latest technological advances in core areas of chemical engineering as well as in other relevant engineering disciplines. To keep abreast with the progressive outlook of the profession, the Journal has been expanding the scope of its editorial contents to include such fast developing areas as biotechnology, electrochemical engineering, and environmental engineering.

  • Impact factor
    2.58
  • 5-year impact
    2.54
  • Cited half-life
    0.00
  • Immediacy index
    0.61
  • Eigenfactor
    0.02
  • Article influence
    0.77
  • Website
    AIChE Journal website
  • Other titles
    AIChE journal (Online), AIChE journal, American Institute of Chemical Engineers journal
  • ISSN
    1547-5905
  • OCLC
    43667889
  • Material type
    Document, Periodical, Internet resource
  • Document type
    Internet Resource, Computer File, Journal / Magazine / Newspaper

Publisher details

John Wiley and Sons

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
    • Author can archive a post-print version
  • Conditions
    • See Wiley-Blackwell entry for articles after February 2007
    • On personal web site or secure external website at authors institution
    • Deposit in institutional repositories is not allowed
    • JASIST authors may deposit in an institutional repository
    • Non-commercial
    • Pre-print must be accompanied with set phrase (see individual journal copyright transfer agreements)
    • Published source must be acknowledged with set phrase (see individual journal copyright transfer agreements)
    • Publisher's version/PDF cannot be used
    • Articles in some journals can be made Open Access on payment of additional charge
    • 'John Wiley and Sons' is an imprint of 'Wiley'
  • Classification
    ​ green

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Economic model predictive control (EMPC) is a control methodology that unites feedback control and real-time process economic optimization (e.g., [1]-[5]). The optimization problem of EMPC consists of three main parts: an objective function that accounts for the process economics, process constraints including state and inputs constraints and other constraints like stability and performance constraints, and a dynamic model to predict the future evolution of the process (thus, be able to select the optimal input profile with respect to the economics over an operating horizon). Regardless of the implementation strategy of EMPC (i.e., centralized, distributed, or hierarchical), the computation time required to solve the optimization-based controller is non-zero in practice. The computation time may be significant or insignificant depending on the time constants of the process dynamics. When the computation time is significant, using an EMPC that does not account for the delay caused by the computation time may lead to unstable closed-loop operation and/or performance degradation. However, no theoretical work on the closed-loop stability properties of EMPC accounting for the computation delay as been completed. To this end, EMPC for real-time implementation is considered in this work. Specifically, a Lyapunov-based EMPC (LEMPC) [4] explicitly accounting for computational delays is proposed. From a performance perspective, it may be advantageous to provide the EMPC with knowledge of the computation delay when they are significant. Thus, the EMPC is formulated with a model that treats the computational delay as an input time-delay and the average computation time is used to model the input time-delay. From a stability perspective, there is a (theoretical) maximum amount of time that the optimization problem solver may spend in computation and must return a control action by this maximum amount of time to ensure closed-loop stability. A rigorous bound on the maximum amount of computation time to ensure closed-loop is derived. The bound will be used to force the solver to return a control action by the maximum computational time required for stability. By the design of the LEMPC, the returned control action, which may be returned before the solver converges to a (local) solution, is guaranteed to be stabilizing. The proposed LEMPC is demonstrated on a chemical process example to show that closed-loop stability can be maintained in the presence of computation delay. [1] Angeli D, Amrit R, Rawlings JB. On average performance and stability of economic model predictive control. IEEE Transactions on Automatic Control. 2012;57:1615-1626. [2] Amrit R, Rawlings JB, Angeli D. Economic optimization using model predictive control with a terminal cost. Annual Reviews in Control. 2011;35:178-186. [3] Huang R, Harinath E, Biegler LT. Lyapunov stability of economically oriented NMPC for cyclic processes. Journal of Process Control. 2011;21:501-509. [4] Heidarinejad M, Liu J, Christofides PD. Economic model predictive control of nonlinear process systems using Lyapunov techniques. AIChE Journal. 2012;58:855-870. [5] Ellis M, Durand H, Christofides PD. A tutorial review of economic model predictive control methods. Journal of Process Control, in press.
    14 AIChE Annual Meeting; 11/2014
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    ABSTRACT: This study reports the adsorption kinetics and wetting behaviors of three plant-based natural surfactants (Reetha, Shikakai, and Acacia) on the PTFE surface. Adsorption studies of these surfactants on PTFE surface show the equilibrium adsorption time is ~ 15 min, and Langmuir type isotherm fits well for all three surfactants. The contact angle measurements show that the value achieved by Reetha and Acacia solutions are close (~109°), but that is low in the case of Shikakai (98.13°). While comparing the adsorption densities of the surfactants at PTFE-water and airwater interfaces, it has been found that adsorption densities at the PTFE-water interface are low for all three surfactants than that of air-water interface. The alcoholShikakai mixed solutions show non-ideal behavior of surface tension reduction through a strong interaction between alcohol and Shikakai molecules, which in turn, show lower surface tension and contact angle values than that of ideal. © 2014 American Institute of Chemical Engineers AIChE J, 2014
    AIChE Journal 11/2014;
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    ABSTRACT: The modified zeolite A was prepared by a two-step crystallization method to remove scale-forming cations from water and geothermal water. The adsorption kinetics, mechanism and thermodynamics were studied. The calcium ion adsorption capacity of the modified zeolite A was 129.3mg/g (1 mg/g=10-3kg/kg) at 298K. The adsorption rate was fitted well with pseudo second-order rate model. The adsorption process was controlled by film diffusion at the calcium ion concentration less than 250mg/L (1 mg/L=10-3 kg/m3), and it was controlled by intraparticle diffusion at the concentration larger than 250mg/L. The calculated mass transfer coefficient ranged from 2.23×10-5 to 2.80×10-4cm/s (1 cm/s=10-2m/s). Dubinin-Astakhov isotherm model could appropriately describe the adsorption thermodynamic properties when combined with Langmuir model. The adsorption process included not only ion exchange but also complexation between calcium and hydroxyl ions. The adsorption was spontaneous and endothermal in nature. The high adsorption capacity indicates that the modified zeolite A is a good adsorption material for scaling removal from aqueous solution. © 2014 American Institute of Chemical Engineers AIChE J, 2014
    AIChE Journal 11/2014;
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    ABSTRACT: We analyze the flow and mass transfer in a discontinuous reactor configuration consisting of a pair of corotating enclosed disks with a chemical reaction taking place at the disk surfaces. The calculated mass transfer efficiencies do not follow the expected Sh = Sh(Re,Sc) dependence because the overall mass transfer process is not boundary–layer controlled, especially at high Schmidt numbers.It has been found in all of the cases investigated that despite the fact that the reactant concentration is continuously dropping with time its spatial distribution, relative to the volume–averaged value, becomes stationary after a short initial transient. This result implies that the mass transfer efficiency in the discontinuous reactor also becomes stationary and the resulting time–independent value, Sh∞, obtained either directly from calculation or from the fit of the collected results, provides a fairly good estimate of the reactor operation time needed to achieve the target reactant conversion. © 2014 American Institute of Chemical Engineers AIChE J, 2014
    AIChE Journal 11/2014;
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    ABSTRACT: Scale-up of agitated drying processes to minimize particle size changes in Active Pharmaceutical Ingredients can be challenging. Particle agglomeration or attrition problems due to agitated drying are often discovered upon the initial scale-up from the lab to the plant. Traditional laboratory drying equipment has not successfully reproduced the degree of agglomeration or attrition observed at scale. This discrepancy may be attributed to the ability of particulate solids, such as crystalline API's, to transfer stresses from the normal direction into the shearing direction. As batch size increases during scale-up, the compressive and shearing forces experienced by the API increase. To overcome this limitation, a modified laboratory setup was constructed which reproduces the range of hydrostatic pressures observed during scale-up. This work highlights the use of the modified setup to characterize the propensity for particle attrition to occur at different stages of the drying process by measuring impeller torque. Torque measurements of the API powder at different hydrostatic pressures revealed a behavior consistent with Coulomb's law of friction. The torque data obtained from these measurements was used to determine the bulk friction coefficient for API powder beds at different liquid content. Additionally, the amount of work done by the impeller blades was correlated to the degree of particle attrition observed. A workflow for assessing risk of API attrition at scale is described. © 2014 American Institute of Chemical Engineers AIChE J, 2014
    AIChE Journal 11/2014;
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    ABSTRACT: The fundamental principles of chemical product design and associated systematic tools, within a broad domain of chemical products including molecules, formulations and devices, are still under development. In this paper, we propose a simple and fundamental conceptual model that defines the chemical product design problem as the inversion of three central design functions: quality, property and process functions. The classic iterative cycles of product design problems may be envisioned as alternating between inversion and evaluation of these three functions, or in other words alternating between synthesis and analysis of solutions. On top of the proposed basic structure of the overall design problem, we then discuss the formulation of some subproblems as optimization problems and describe some useful solution tools. Three application examples are provided, including a more detailed case of formulation of a pharmaceutical ointment. This article is protected by copyright. All rights reserved.
    AIChE Journal 11/2014;
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    ABSTRACT: A novel low pressure device was used to generate nanoemulsions of methyl methacrylate. This device is based on a strong elongational flow known to be more efficient than the shear flow for dispersive mixing. The influence of process parameters (pressure drop number of cycles, number and size of holes) and composition parameters (monomer fraction, surfactant concentration,…) on droplet size has shown that the average droplet size can be tailored in the range 30 – 200 nm by adjusting these parameters. The objective of the present paper is to find correlations that relate the obtained droplet size to the studied process and composition parameters. This model is based on a dimensional analysis using the Buckingham theorem in order to determine appropriate dimensionless numbers. This approach represents a first step for scaling up the device besides giving a set of parameters allowing to achieve a given droplet size. This article is protected by copyright. All rights reserved.
    AIChE Journal 11/2014;
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    ABSTRACT: A comprehensive optimization model that can determine the most cost-effective and environmentally sustainable production pathways in an integrated processing network is needed, especially in the bioconversion space. We develop the most comprehensive bioconversion network to date with 193 technologies and 129 materials/compounds for fuels production. We consider the tradeoff between scaling capital and operating expenditures (CAPEX and OPEX) as well as life cycle environmental impacts. Additionally, we develop a general network-based modeling framework with non-convex terms for CAPEX. To globally optimize the nonlinear program with high computational efficiency, we develop a specialized branch-and-refine algorithm based on successive piecewise linear approximations. Two case studies are considered. The optimal pathways have profits from -$12.9M/yr to $99.2M/yr, and emit 791 ton CO2-eq/yr to 31,571 ton CO2-eq/yr. Utilized technologies vary from corn-based fermentation to pyrolysis. The proposed algorithm reduces computational time by up to three orders of magnitude compared to general-purpose global optimizers. © 2014 American Institute of Chemical Engineers AIChE J, 2014
    AIChE Journal 11/2014;
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    ABSTRACT: In the presence of supercritical water (SCW) and N2, the pyrolysis of heavy oil was investigated to distinguish the difference in the reaction kinetics between the upgrading in the SCW and oil phases. The pyrolysis in the SCW phase is faster than that in the oil phase, but the reaction in whichever phase is retarded by vigorous stirring. The pyrolysis can be preferably described by a four-lump kinetic model consisting of the condensation of maltenes and asphaltenes in series. In the SCW phase, highly dispersed asphaltenes are isolated by water clusters from maltenes dissolved in SCW surroundings, by which the condensation of asphaltenes is drastically accelerated. Benefited from excellent mass transfer environments in SCW, the condensation of maltenes is promoted simultaneously. The introduction of SCW into the pyrolysis of heavy oil results in an effectively increased upgrading efficiency, but its influence on the properties of equilibrium liquid products is minor. © 2014 American Institute of Chemical Engineers AIChE J, 2014
    AIChE Journal 11/2014;
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    ABSTRACT: This work investigates CO2 removal by single and blended amines in a hollow-fiber membrane contactor (HFMC) under gas-filled and partially liquid-filled membrane pores conditions via a two-scale, non-isothermal, steady-state model accounting for CO2 diffusion in gas-filled pores, CO2 and amines diffusion/reaction within liquid-filled pores and CO2 and amines diffusion/reaction in liquid boundary layer. Model predictions were compared with CO2 absorption data under various experimental conditions. The model was used to analyze the effects of liquid and gas velocity, CO2 partial pressure, single (primary, secondary, tertiary and sterically hindered alkanolamines) and mixed amines solution type, membrane wetting and concurrent/countercurrent flow orientation on the HFMC performance. An insignificant difference between the absorption in cocurrent and countercurrent flow was observed in the present study. The membrane wetting decreases significantly the performance of hollow-fiber membrane module. The non-isothermal simulations reveal that the hollow-fiber membrane module operation can be considered as nearly isothermal. © 2014 American Institute of Chemical Engineers AIChE J, 2014
    AIChE Journal 11/2014;
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    ABSTRACT: An accurate prediction of tray hydraulics is very important for large diameter trays design, and vapor cross-flow channeling is one of the key points that affect the hydraulics calculation. Therefore, in this article, a theoretical analysis was first conducted to reveal that the energy of gas-liquid on the tray was closely related to its flow state. Then, a model was obtained on the basis of the principle of the lowest energy, which can be used to calculate vapor cross-flow channeling. The model shows that the ratio of dry tray pressure drop to liquid height on a tray determines the gas distribution on the tray. Finally, the model was tested by comparisons with experimental results available in reference. The agreements are good. Furthermore, the effects of liquid load and fractional hole area on vapor cross-flow channeling were studied. The results are consistent with the field experience summarized in literatures. This article is protected by copyright. All rights reserved.
    AIChE Journal 11/2014;
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    ABSTRACT: In this study, a relatively precise kinetic mechanism of NOx reduction using N2H4·H2O in a selective non-catalytic reduction (SNCR) process was proposed and verified by experiment. The dominant radicals and reactions were confirmed, and the proper ranges of key parameters were determined through sensitivity analysis. Both experiment and simulation results show that the effective temperatures exhibit a bimodal distribution with the optimum temperatures being approximately 893K and 1248K and the lower temperature window falling in the range of 848 to 973K. The optimum residence time of the reaction was 0.2~0.35s under the research conditions, and a longer residence time would lead to the re-generation of NOx. The normalized stoichiometric ratio (NSR) of 3.0 corresponded to the lowest temperature window, and a higher NSR value would make the temperature window shift to a higher temperature range. This kinetic mechanism model for the N2H4·H2Obased De-NOx process will serve its precise application. This article is protected by copyright. All rights reserved.
    AIChE Journal 11/2014;
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    ABSTRACT: Economic model predictive control (EMPC) is a feedback control technique that attempts to tightly integrate economic optimization and feedback control since it is a predictive control scheme that is formulated with an objective function representing the process economics. As its name implies, EMPC requires the availability of a dynamic model to compute its control actions and such a model may be obtained either through application of first-principles or through system identification techniques. In industrial practice, it may be difficult in general to obtain an accurate first-principles model of the process. Motivated by this, in the present work, Lyapunov-based EMPC (LEMPC) is designed with a linear empirical model that allows for closed-loop stability guarantees in the context of nonlinear chemical processes. Specifically, when the linear model provides a sufficient degree of accuracy in the region where time-varying economically optimal operation is considered, conditions for closed-loop stability under the LEMPC scheme based on the empirical model are derived. The LEMPC scheme is applied to a chemical process example to demonstrate its closed-loop stability and performance properties as well as significant computational advantages. This article is protected by copyright. All rights reserved.
    AIChE Journal 11/2014;
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    ABSTRACT: The efficient transfer of high-temperature solar heat to the reaction site is crucial for the yield and selectivity of the solar-driven gasification of biomass. This work investigates the performance of a gas-solid trickle-bed reactor constructed from a high thermal conductivity porous ceramic packing. Beech char particles were used as the model feedstock. A two-dimensional finite-volume model coupling chemical reaction with conduction, convection, and radiation of heat within the packing was developed and tested against measured temperatures and gasification rates. The sensitivity of the gasification rate and reactor temperatures to variations of the packing's pore diameter, porosity, thermal conductivity, and particle loading was numerically studied. A numerical comparison with a moving bed projected a more uniform temperature distribution and higher gasification rates due to the increased heat transfer via combined radiation and conduction through the trickle bed. © 2014 American Institute of Chemical Engineers AIChE J, 2014
    AIChE Journal 11/2014;
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    ABSTRACT: Kinetic modeling provides chemical engineers with a unique opportunity to better understand reaction kinetics in general and the underlying chemistry in particular. How to systematically approach a modeling assignment in chemical reaction kinetics is typically less clear, especially for novices in the field.The proposed modeling methodology pursues an adequate compromise between statistical significance and physical meaning of the kinetic model and the corresponding parameters and typically results in models of an appropriate complexity. It comprises the following activities: (i) data analysis, aiming at qualitative information on the reaction mechanism and corresponding rate equations, (ii) model regression to quantify this information via optimal parameter values and (iii) validation of the statistical significance and physical meaning of the parameter estimates. This methodology is successfully applied to n-hexane hydroisomerization on a bifunctional catalyst. © 2014 American Institute of Chemical Engineers AIChE J, 2014
    AIChE Journal 11/2014;
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    ABSTRACT: The direct recovery of methane from methane hydrate bearing sediments is demonstrated, where a gaseous mixture of (CO2+N2) is used to trigger a replacement reaction in complex phase surroundings. A 1D high-pressure reactor (8 m) was designed to test the actual aspects of the replacement reaction occurring in natural gas hydrate reservoir conditions. Natural Gas Hydrate (NGH) can be converted into CO2 hydrate by a ‘replacement mechanism,’ which serves double duty as a means of both sustainable energy source extraction and greenhouse gas sequestration. The replacement efficiency controlling totally recovered CH4 amount is inversely proportional to (CO2+N2) injection rate directly affecting contact time. A qualitative analysis on compositional profiles at each port reveals that the length more than 5.6 m is required to show noticeable recovery rate for NGH production. The present outcomes are expected to establish the optimized key process variables for near future field production tests. This article is protected by copyright. All rights reserved.
    AIChE Journal 11/2014;
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    ABSTRACT: The use of ethanol as a fuel for motor engines has attracted significant attention because of its possible environmental and economic advantages over fossil fuel. However, the energy demand for the ethanol dehydration process significantly impacts its production cost. A new and energy efficient process is developed on the basis of salt extractive distillation, which uses recycled MgCl2 granules as a separating agent. Vapor-liquor-equilibria (VLE) data for the ternary MgCl2 + ethanol + water system and the three constituent binary systems were measured at 30, 60, 90 and 101.3 kPa. A large enhancement of relative volatility of the ethanol + water system in the presence of MgCl2 is observed throughout the entire ethanol concentration range, which completely broke the azeotrope. The salt effect of MgCl2 is thought to be the result of energetic interactions and the hydration equilibrium reaction of the Mg2+ ion with water molecules. The calculation results by the mixed-solvent electrolyte (MSE) model embedded in the OLI platform equipped with new model interaction parameters and equilibrium constant (obtained via the regression of experimental VLE data), provided for a satisfactory means of simulating the MgCl2 salt extractive distillation process. Finally, the process was proven feasible at the laboratory-scale resulting in large granules of recovered MgCl2 and a product of 99.5 wt% ethanol. This article is protected by copyright. All rights reserved.
    AIChE Journal 11/2014;
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    ABSTRACT: A systematic study of CO2 capture on the amine-impregnated solid adsorbents is carried out at CO2 concentrations in the range of 400-5000 ppm, relating to the direct CO2 capture from atmospheric air. The commercially available polymethacrylate-based HP2MGL and polyethylenimine are screened to be the suitable support and amine respectively for preparation of the adsorbent. The adsorbents exhibit an excellent saturation adsorption capacity of 1.96 mmol/g for 400 ppm CO2 and 2.13 mmol/g for 5000 ppm CO2. Moisture plays a promoting effect on CO2 adsorption but depends on the relative humidity. The presence of O2 would lead to the decrease of adsorption capacity, but do not affect the cyclic performance. The diffusion additive is efficient to improve the adsorption capacity and cyclic performance. Moreover, the adsorbents can be easily regenerated under a mild temperature. This study may have a positive impact on the design of high-performance adsorbents for CO2 capture from ambient air. © 2014 American Institute of Chemical Engineers AIChE J, 2014
    AIChE Journal 11/2014;
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    ABSTRACT: The Ideal Adsorbed Solution (IAS) theory has been shown to predict reliably multicomponent adsorption for both gas and liquid systems. There is a lack of understanding of the conditions which guarantee convergence for various algorithms used to solve the IAS theory equations and inconsistencies are present in the reported computational effort required for the different approaches. The original nested loop and the FastIAS technique are revisited. The resulting system of equations is highly nonlinear but both methods are shown to be robust if appropriate choices are made for the starting values of the unknown variables. New initial conditions are proposed and the resulting algorithms are compared in a consistent manner with the main methods available to solve the IAS theory equations. The algorithms are extended for the first time to all non-type I isotherms. This article is protected by copyright. All rights reserved.
    AIChE Journal 11/2014;
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    ABSTRACT: Carbon dioxide (CO2) decomposition was carried out at a normal atmosphere and room temperature in dielectric barrier discharge (DBD) microplasma reactors to reduce CO2 emissions and convert CO2 into valuable chemical materials. The outlet gases, including CO2, CO, and O2, were analyzed with gas chromatography. The results indicated that the conversions of CO2 in dielectric material-packed reactors were all higher than that in non-packed reactors. Particle size, dielectric constant, particle morphology, and acid-base properties of the dielectric materials (including quartz wool, quartz sand, γ-Al2O3, MgO, and CaO) all affected the CO2 decomposition process. The conversion of CO2 and energy efficiency achieved the highest values of 41.9 % and 7.1 % in a CaO-packed reactor for the higher dielectric constant and basicity of CaO. Quartz wool was also an excellent dielectric packing material because its fiber structure provided rigid sharp edges. This article is protected by copyright. All rights reserved.
    AIChE Journal 11/2014;