Use of an “Unreacted Shrinking Core” Model in the Reaction of H2S with Perovskite-Type Sorbents

An “unreacted shrinking core” model was used to describe the behavior of a fixed-bed reactor during the reaction between gas-phase H 2 S and perovskite-type sorbents (i.e., La 2 CuO 4, LaMnO 3, and LaCoO 3 ). Optimization of a single adjustable parameter (i.e., the effective diffusivity of H 2 S through the sulfided perovskite layer) results in an excellent agreement between experimental H 2 S breakthrough curves and model predictions for different sorbents, temperatures, and H 2 S inlet concentrations. The values of effective diffusivity thus obtained are on the order of 2−10 cm 2 /h. For La 2 CuO 4, for which data were available at different temperatures, the effective diffusivity was also found to follow an Arrhenius-type expression with an activation energy of approximately 3 kcal/mol.