Reaction and Heat Transfer Characteristics of Catalyst-Coated Fins

• Project/Area Number: 09650231
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Thermal engineering
• Research Institution: Yokohama National University
• Principal Investigator: OKUYAMA Kunito Yokohama National University, Graduate School of Engineering, Associate Professor, 大学院工学研究科, 助教授 (60204153)
• Co-Investigator(Kenkyū-buntansha): IIDA Yoshihiro Yokohama National University, Faculty of Engineering, Professor, 工学部, 教授 (90005299)
• Project Period (FY): 1997 – 1998
• Project Status: Completed (Fiscal Year 1998)
• Budget Amount: ¥1,700,000 (Direct Cost: ¥1,700,000); Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000); Fiscal Year 1997: ¥1,200,000 (Direct Cost: ¥1,200,000)
• Keywords: Fin / Catalyst / Endothermic Reaction / Fin Efficiency / Analysis / Methanol Decomposition / Washcoat / Catalyst / Endothemic Reaction / Methanol decomposition

Research Abstract

In Chapter 1, the reaction and heat transfer characteristics of catalyst-coated fins, which are used to circumvent low catalyst loadings in wall-supported catalytic reactors, were investigated theoretically in an attempt to examine the effects of important non-dimensional parameters on fin performance for endothermic reaction cases. The fin efficiency of the reaction rate was found to decrease markedly, more than that of convection heat transfer, with an increase of heat absorption rate by the reaction and/or the convection heat transfer rate, for the case in which the conversion rate is governed by the intrinsic kinetics of the catalyst. The increase of bulk fluid temperature to the fin base temperature increased the fin efficiency of the reaction rate, under chemical kinetics limitation, due to convection heating of the fin while the fin temperature decreases along the structure due to heat absorption.
In Chapter 2, the reaction and heat transfer characteristics of a platinum-catalyst -coated fin with methanol decomposition reaction were investigated experimentally. Fin base temperature was varied widely over the range of practical interest. The local temperature along the fin structure and the evolution rate of decomposed gas measured agreed well with those predicted by the analytical model shown in the preceding chapter. For the ranges of parameters examined, the effects of the mass transfer of reactant species from bulk fluid onto the fin surface and the heat absorption by the reaction on fin efficiencies of the reaction rate and heat transfer were shown to be negligibly small. For the case in which the reaction rate on the fin surface is not affected by the mass transfer onto the fin surface and the heat absorption by reaction in general, one dimensionless quantity, which is expressed as a function of dimensionless parameters, was shown to be dominant for fin efficiency of the reaction rate in the practically possible ranges of dimensionless parameters. The simple approximation of fin efficiency of the reaction rate expressed in terms of the dominant dimensionless quantity well predicted the results obtained by the experiment.