Heat exchange between two coupled moving beds by fluid flow

Heat exchange between a moving bed and fluid flow is considered. The arrangement of flows of fluid and solids can be in parallel flow, counter-flow or cross-flow. The effect of possible phase change is considered using a simplified model. Heat exchange by forced fluid flow between two coupled moving beds containing solids can be used to recover heat from hot products to cool input in many industrial processes. There are several ways to couple such two moving beds. Analytical solutions for the fluid and solid temperature distributions and heat recovery effectiveness are presented for continuous operation for single moving beds and two beds coupled by a fluid flow. The intra-particle transient temperature distributions are accounted for in the more accurate analysis and the results are compared to lumped analysis and an approximate solution. The heat recovery effectiveness of a coupled system reaches maximum at certain optimum flow rate of the fluid. Analogy between regenerators and heat recovery systems consisting of two moving beds coupled by an unmixed flow of fluid is found. Due to this analogy many different calculation methods, tables and formulas developed for to evaluate temperatures and thermal effectiveness of regenerators can be used to study heat recovery from solids.