REACTIVITY OF FE2O3 WITH H2S CONTAINED IN LOW-CALORIE SYNGAS

For high-temperature direct removal of H2S from low-calorie syngas, the reactivity of an Fe2O3 pellet with hot simulated gas containing H2S was studied by means of TGA (Thermal Gravimetric Analysis) over a temperature range of 600~900°C. It has been concluded within the experimental conditions employed that: (1) The weight change during the simultaneous reduction-sulfurization run seems to be derived by simply adding the two curves obtained from reduction and sulfurization respectively. (2) The ultimate conversion of the reduction run is 0.95 ±0.05, and at final stage of the sulfurization run the stoichiometric ratio of S to Fe reaches 1.1 ±0.1. (3) The values of activation energy are 13.0 and 1.5 kcal/mol for the reduction and sulfurization, respectively. (4) For pellets smaller than 1.1 mm in diameter, the intrinsic reaction rate seems to dominate the overall sulfurization rate. The intrapellet diffusion effect becomes increasingly significant as pellet size increases beyond 1.1 mm. The theoretical over-all sulfurization rate showed fairly good coincidence with the measured rate when the intrapellet diffusivity of H2S was assumed to be second-order with respect to the macro-porosity in the product layer. © by THE SOCIETY OF CHEMICAL ENGINEERS, JAPAN.