Thermal analysis and optimization of a heat regenerator composed of two coupled moving bed heat exchangers

Abstract

This work presents a study to optimize the performance of a heat regenerator composed by two coupled moving bed heat exchangers (MBHE). A MBHE is used to recover heat, from a hot gas stream, and the other one is used to preheat an air stream. A direct application might be a gasifier. The heat exchangers performance was studied in two cases, considering or not the conduction heat transfer in the solid phase. When the solid conduction is taken into account, a numerical solution is obtained, while an analytical solution is possible when the conduction terms are neglected. In both cases, the optimum values of bed length (in the air flow direction) and particle diameter were obtained from an exergy point of view. Finally, an energy optimization of the heat regenerator was carried out, obtaining the optimal heat regenerator dimensions as a function of gas velocity and gas flow rate.