HEAT-EXCHANGE CHARACTERISTICS OF TUBE-WAL L REACTOR AT EXOTHERMIC ENDFOR HIGH-TEMPERATURE CHEMICAL HEAT-PIPE

The heat-exchange characteristics accompanied by exothermic reaction a t the heat-demand end of a chemical heat pipe system using a SO2/SO3 r eversible thermochemical reaction was examined in a lab-scale unit. Un der the experimental conditions employed it was found that the convers ion by SO2-oxidation reached almost equilibrium value and the heat-exc hange medium (air) was well heated by the heat of reaction. The effect s of reactant gas composition, mass flow rate of reactant gas and heat exchange medium on the reaction and the heat exchange characteristics were studied. Furthermore, a comparison between experimental and calc ulated results obtained by using a two-dimensional mathematical model, in which the reaction and heat transfer was considered simultaneously , was performed. It was found that the heat exchange characteristics o btained from experiments can be explained by the calculated results. U nder adiabatic conditions, the temperature difference between the outl et and the inlet of the heat exchange medium increased with increase o f the mass flow rate of SO2 and decrease of the mass flow rate of the heat exchange medium, while the efficiency of the heat exchange proces s decreased with increase of the mass flow rate of SO2 and decrease of the mass flow rate of the heat exchange medium.