The reductive decomposition of calcium s

The reductive decomposition of calcium sulphate by hydrogen is employed for the regeneration of calcium-based atmospheric fluidized bed combustion (AFBC) SO2 sorbents. This study investigates the apparent solid-solid reaction between CaS and CaSO4, which is a crucial step in the reaction mechanism of the reductive decomposition of CaSO4. A thermobalance system coupled with product gas analysis was utilized to study this reaction separately under controlled conditions. The reaction was observed when a mixture of the compounds was heated in an inert atmosphere to temperatures exceeding 1100 K: CaSO4 + CaS → CaO + SO2. The results indicated that the fractional production rate of CaO (or SO2) neared dependence on the initial ratio of CaSO4 and CaS. A straightforward model was also proposed for calculating the fractional production rate concerning the initial composition and the degree of production. Key assumptions of this model included the formation of a liquid phase from CaS and CaSO4 mixtures. The computed production rates, based on the established model parameters such as kinetic constants and the characteristics of the liquid phase, showed strong agreement with experimental results.