Procedures for heat recovery in the catalytic combustion of lean methane-air mixtures in a reverse flow reactor

The performance of different heat recovery strategies for reverse flow catalytic reactors, considering both the gas extracting point (centre or end) and the possibility of returning the cooled gases, has been studied in this work. The study was carried out by means of simulations of the combustion of methane over a monolithic Pd-catalyst using a heterogeneous I D dynamic model. The effect of methane feed concentration (3000-9000 ppmV), has also been considered. The withdrawal of the hot gases from the end of the catalytic bed without returning the cooled gases has been shown to provide the most stable performance, whereas the extraction of the gases from the central part of the bed severely affects reactor performance. Finally. the amount of high-pressure steam that can be generated using the best heat recovery method has been also estimated. (C) 2008 Elsevier B.V. All rights reserved.