Parametric study of microreactor design for water gas shift reactor using an integrated reaction and heat exchange model

Kim, Gap Yong; Mayor, J. Rhett; Ni, Jun

doi:10.1016/j.cej.2004.05.015

Cited by 33 publications

(11 citation statements)

References 9 publications

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“…As a rough guide, the deviation from the flat profile of velocity assumed in plug flow is not more than 20%, provided that the tube diameter is at least 30 × the particle diameter (Trimm, 1980). To guarantee that the flow pattern in the membraneless reactor was plug flow, we established that the smallest dimension of the microchannel should be 50 times greater than the catalyst bed particle diameter; this leads to d p = 1×10 −5 m because the microchannel had H = 5×10 −4 m. Many published papers that used metal catalysts supported on alumina have catalyst densities in the range of 1-2×10 6 g/cm 3 (Falco and Gallucci, 2010;Kim et al, 2005;Kawamura et al, 2006;Wang and Rodrigues, 2005;Lee et al, 2006). The value of the catalyst density used in this work (ρ cat =1.35×10 6 g/cm 3 ) was adjusted to obtain a space time equivalent to that used by Comas et al (2004b) in his experimental measurements.…”

Section: Resultsmentioning

confidence: 99%

Parametric study of hydrogen production from ethanol steam reforming in a membrane microreactor

DeSouza

Zanin

Moraes

2013

Braz. J. Chem. Eng.

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-Microreactors are miniaturized chemical reaction systems, which contain reaction channels with characteristic dimensions in the range of 10-500 μm. One possible application for microreactors is the conversion of ethanol to hydrogen used in fuel cells to generate electricity. In this paper a rigorous isothermal, steady-state two-dimensional model was developed to simulate the behavior of a membrane microreactor based on the hydrogen yield from ethanol steam reforming. Furthermore, this membrane microreactor is compared to a membraneless microreactor. A potential advantage of the membrane microreactor is the fact that both ethanol steam reforming and the separation of hydrogen by a permselective membrane occur in one single microdevice. The simulation results for steam reforming yields are in agreement with experimental data found in the literature. The results show that the membrane microreactorpermits a hydrogen yield of up to 0.833 which is more than twice that generated by the membraneless reactor. More than 80% of the generated hydrogen permeates through the membrane and, due to its high selectivity, the membrane microreactor delivers high-purity hydrogen to the fuel cell.

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Section: Resultsmentioning

confidence: 99%

Parametric study of hydrogen production from ethanol steam reforming in a membrane microreactor

DeSouza

Zanin

Moraes

2013

Braz. J. Chem. Eng.

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“…In the WGS reactor the CO content should be reduced to an acceptable level (for the fuel cell stack) of less than 2%. The kinetic model of the WGS reactor is described in detail in Kim et al [27], and global reaction considered is expressed as follows:…”

Section: Methane Steam Reformer (Msr)mentioning

confidence: 99%

Parametric Analysis of a High Temperature PEM Fuel Cell Based Microcogeneration System

Nomnqa

Ikhu-Omoregbe

Rabiu

2016

International Journal of Chemical Engineering

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This study focuses on performance analysis of a 1 kWemicrocogeneration system based on a high temperature proton exchange membrane (HT-PEM) fuel cell by means of parametric investigation. A mathematical model for a system consisting of a fuel processor (steam reforming reactor and water-gas shift reactor), a HT-PEM fuel cell stack, and the balance-of-plant components was developed. Firstly, the fuel processor performance at different fuel ratios and equivalence ratio was examined. It is shown that high fuel ratios of 0.9–0.95 and equivalence ratios of less than 0.56 are suitable for acceptable carbon monoxide content in the synthetic gas produced. Secondly, a parametric study of the system performance at different fuel and equivalence ratios using key system operating parameters was conducted. Steam-to-carbon ratio, stack operating temperature, and anode stoichiometry were varied to observe the changes in the microcogeneration system. The analysis shows that the system can reach electrical and cogeneration efficiencies of 30% and 84%, respectively.

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“…Various reactor configurations have been explored for carrying out the WGS reaction for different applications. − Various designs of membrane reactors have been proposed to obtain a nearly pure hydrogen stream instead of a hydrogen-rich product containing CO. Recent studies have also considered microreactors with heat exchange, which have benefits such as near-isothermal operation, lower catalyst loading, and lower reactor volume as compared to conventional fixed-bed reactors. − Experimental and modeling studies have been carried out for the investigation of chemical-looping WGS reactor systems which consider the oxidation of CO and the formation of H 2 in two separate reactors. , Sorption-enhanced WGS reaction in membrane and fluidized bed reactors has been explored to integrate the CO 2 capture process with the WGS reaction. , Other novel configurations consider the use of structured catalysts to overcome the kinetic and thermodynamic limitations for the WGS reaction. , However, considering the industrial experience with the operation of fixed-bed reactors, the WGS reaction is usually carried out in a single fixed-bed reactor or a system of multiple such reactors, with the target of maximizing the conversion of CO.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Modeling and Optimization of a Fixed-Bed Reactor for the Partial Water–Gas Shift Reaction

Kherdekar

Roy

Bhatia

2021

Ind. Eng. Chem. Res.

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This work presents an approach for the model-based design of a load-flexible fixed-bed reactor for performing the partial water–gas shift (WGS) reaction in the gas cleanup section of a coal-to-methanol plant. Three optimization problems with various combinations of objective functions (H2/CO ratio, pressure drop, and operating costs) are formulated and solved using the nondominated sorting genetic algorithm (NSGA-II) to obtain the Pareto-optimal fronts, and the selected solutions are subjected to dynamic stability analysis. The optimum values of decision variables such as the weight of the catalyst, catalyst particle size, ratio of the reactor length and diameter, feed gas temperature, and steam to CO ratio are estimated and are found to be dependent on the choice of the objectives and tolerable deviation from their required values. The dependence of the H2/CO ratio on the inlet gas temperature varies with the choice and combination of the objectives. In contrast, higher values of the steam to CO ratio (S/C) are associated with a lower deviation from the desired H2/CO ratio for all three cases. However, optimum values of S/C are found to be below 1:1 because of its effect on the pressure drop and operating costs. The solutions obtained in the equilibrium-limited regime are found to be more stable in the presence of fluctuations in the feed flow rates but show intermediate stability with fluctuations in the inlet gas temperature. Four designs are recommended as the feasible designs, and the criteria of their application are discussed. Even though the work is related to a WGS reactor, the methodology used can be applied for the design of any other reactor system operating under variable feed conditions.

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Parametric study of microreactor design for water gas shift reactor using an integrated reaction and heat exchange model

Cited by 33 publications

References 9 publications

Parametric study of hydrogen production from ethanol steam reforming in a membrane microreactor

Parametric study of hydrogen production from ethanol steam reforming in a membrane microreactor

Parametric Analysis of a High Temperature PEM Fuel Cell Based Microcogeneration System

Dynamic Modeling and Optimization of a Fixed-Bed Reactor for the Partial Water–Gas Shift Reaction

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