Development and testing of regenerable hot-coal-gas desulfurization sorbents

Investigations over several years at the Morgantown Energy Technology Center have been concerned with the development of a regenerable metal oxide desulfurization sorbent which would function on hot coal-derived fuel gas. In the latest phase of testing, a combination of zinc oxide with iron oxide as zinc ferrite has produced a sorbent which has demonstrated regenerability and capability of removing sulfur from simulated hot coal gas to a level of 1 to 10 ppM by volume. The principal finding at this stage of the project is that the compound zinc ferrite and also iron oxide containing some zinc ferrite have hydrogen sulfide absorption performances very similar to those of zinc oxide. Extruded sorbents made from these compounds have been demonstrated to perform with varying ability in the temperature range 800/sup 0/F (427/sup 0/C) to 1400/sup 0/F (760/sup 0/C) at a space velocity of 2000 hourly and a hydrogen sulfide concentration of 2.7 percent. They have also been shown to be regenerable with a 50/50 percent v/v steam-air mixture at 1000/sup 0/F (538/sup 0/C) and 600 hourly space velocity with no loss of absorptive power. Both zinc ferrite and zinc oxide appear to perform optimally in the middle of the temperature range, where absorption capacity is greatest. Surprisingly, the experimental results indicate no trend to a lower degree of hydrogen sulfide removal with rise in temperature. Zinc ferrite appears to be superior to zinc oxide in terms of its absorption capacity and resistance to sintering at higher temperatures