Effect of wall properties on the behavior of bench‐scale reverse flow reactors

Abstract

AbstractAlthough in big‐sized industrial fixed bed combustors the effect of the reactor wall in heat transfer phenomena can often be neglected, this is not so for smaller reactors. This article focuses on the study of the wall influence (especially the effect of the wall physical properties, such as thickness, heat capacity, and thermal conductivity) in the performance of bench scale reverse flow reactors. The reaction considered is the combustion of methane lean mixtures, very relevant for environmental applications, and useful as a model for VOC combustion. The study was carried out both experimentally (in a bench‐scale apparatus, equipped with a temperature control system that minimizes the heat exchange between the reactor and the surroundings) and by simulations (using a heterogeneous one‐dimensional model). The results confirm the importance of the wall effects on the performance of reverse flow reactors, and the influence of the physical properties of the wall is reported. So, higher wall thermal conductivity leads to a decrease in the reactor stability range. High wall heat capacity is also detrimental for the reactor performance, although its effect depends strongly on the range of the wall thermal conductivity considered. Finally, the stability range of reverse flow reactors is less affected by wall effects as the surface velocity increases. © 2006 American Institute of Chemical Engineers AIChE J, 2006