Unsteady heat transfer in a packed bed-type heat regenerator by use of a CaO/Ca(OH)/sub 2/ reversible thermochemical reaction

This paper examines a packed bed-type regenerative heat exchanger by use of the CaO/Ca(OH)/sub 2/ reaction system as designed and operated. The experimental results were compared with the calculated ones in terms of the unsteady temperature changes of the packed bed and the steam, and the heat-release characteristics of this heat exchanger were discussed. As a result, it was found that the CaO packed bed attained the pseudo-equilibrium reaction temperature of about 783.2 K throughout the entire part of the bed, immediately after the steam was introduced. In this heat-release period, the reaction was found to proceed successively from the inlet to the outlet of the bed with both the temperature and the conversion of reaction kept almost constant throughout the cross section of the bed and with the temperature of steam at the outlet of the bed kept at the almost constant high temperature independently of the initial bed temperature and the steam flow rate, until the reaction was completed. The experimental results agreed fairly well with the calculated ones in terms of the temperature profiles in the packed bed