Hot low Btu producer gas desulfurization in fixed bed of iron oxide-fly ash. Final report, 1 July 1975--30 April 1977. Volume I

This work was undertaken to support the Morgantown Energy Research Center on their development of a process for desulfurizing hot, low BTU producer gas with iron oxide sorbents. Specific objectives were sorbent development and definition of scale-up criteria for commercial design. Several experimental sorbents were prepared using commercially available raw materials and were tested for capacity for hydrogen sulfide removal from the producer gas. Effects of iron oxide source, iron oxide content, sorbent support and binder on sorbent performance were investigated. Changes in properties like porosity, crushing strength, surface area, attrition resistance, x-ray diffraction patterns, DTA, density of the sorbents after undergoing a single absorption and regeneration cycle were evaluated. Effects of process variables like GHSV, superficial velocity, temperature, H/sub 2/S concentration in producer gas, pellet diameter, iron oxide content and pressure on the absorption dynamics were experimentally determined. Several mathematical models to describe the isothermal sorption of H/sub 2/S were developed. All the models were evaluated using experimental data. The semi-empirical model was able to predict the shapes of breakthrough curves and sorbent performance at 10% breakthrough for H/sub 2/S. Several schemes were considered to regenerate sulfided sorbents and yield a high concentration of sulfur dioxide without exceeding 1500/supmore » 0/F. A short experimental program was completed to study effects of process variables on regeneration dynamics using air-stream. Heat effects for the highly exothermic regeneration were incorporated in the isothermal sorption models and were tested with experimental data. The adiabatic kinetically controlled model was best able to correlate the regeneration data.« less