Thermal Transport Characteristics of Heat-Integrated Heterogeneous Catalytic Reactors for Hydrogen Production
13 Pages Posted: 4 Aug 2022
Date Written: July 29, 2022
There is a continuing effort to perform steam reforming reactions in heat-integrated microchannel reactors. However, the mechanisms for the effects of design factors on thermal transport characteristics are still not fully understood. This study relates to a thermochemical process for producing hydrogen by the catalytic endothermic reaction of methanol with steam in a heat-integrated heterogeneous catalytic reactor. Computational fluid dynamics simulations are conducted to better understand the consumption, generation, and exchange of thermal energy between endothermic and exothermic processes in the heat-integrated heterogeneous catalytic reactor. The effects of wall heat conduction properties on thermal transport characteristics and reactor performance are investigated. The objective of this study is to gain insight into the fundamental characteristics of thermal transport in heat-integrated heterogeneous catalytic reactors. Particular emphasis is placed on the dependence of thermal transport characteristics on wall heat conduction properties in various situations, with an attempt to improve the distribution of thermal energy for use in heat-integrated heterogeneous catalytic reactors. The results indicate that reactors having different thermal interface surface areas may be thermally coupled in any suitable manner. Thermal coupling may further serve to match the reaction in one reactor to the reactor with which it is coupled. Intrinsic properties of the porous material can be chosen to provide flow channels with varying degrees of surface area. Essentially, there are an unlimited number of ways in which the heat-integrated heterogeneous catalytic reactor can be tailored to suit a particular reaction by adjusting parameters including the surface area of the reactor, thermal conductance, and hydraulic diameter of the passages. A disadvantage of the reactor geometry is that the operating temperatures of the two reactions must be similar since the separate streams are separated only by the thin separating and heat transfer plate. Thermally matching the reactions is still further complicated by the inherent temperature gradients that are present along the flow length of the reaction channel. Any solution directed to resolving this thermal matching problem in a parallel flow configuration will add significant complexity or mass to the system.
Keywords: Catalytic reactions; Heterogeneous catalysis; Fuel cells; Chemical kinetics; Physical adsorptions; Transport phenomena
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