PERCOLATION CONCEPTS IN MODELING OF GAS SOLID REACTIONS .3. APPLICATION TO SULFATION OF CALCINED LIMESTONE

A Bethe network description of porous solids is used to model pore structure changes, including pore plugging, in the sulfation of calcined limestone. This model accounts for diffusion of SO//2 in the shrinking pore space as well as in the product layer. The model predictions clearly demonstrate the increasing diffusion resistance and isolation of partially reacted pores causing incomplete conversion of the solid. The importance of an accurate description of pore space topology both in the interpretation of Hg porosimetry data and in transport calculations is illustrated. The model simulations show excellent agreement with published experimental observations.