EXPERIMENTAL AND THEORETICAL INVESTIGATION OF FACTORS AFFECTING THE DIRECT LIMESTONE-H2S REACTION

The factors influencing the behavior of the CaCO3-H2S reaction were in vestigated. Three types of limestones, all having high CaCO3 content ( >95 % on a mass basis) but differing in petrographic structure. were r eacted with H2S in a thermogravimetric analysis system under noncalcin ing conditions, that is, in the presence of enough CO2 to prevent deco mposition of CaCO3. Experiments were carried out over a range of parti cle size, temperature, and H2S concentration. Pore structure character ization suggested that the particle size decreased during the reaction . The data were analyzed using a shrinking core model, and the effecti ve diffusivity through the product layer was found to vary significant ly among the three solids. The obtained results were compared with rea ctivity data reported for the same stones for the CaCO3-SO2, CaO-SO2, and CaO-H2S reactions in past studies.