Ceria−Zirconia High-Temperature Desulfurization Sorbents

Ceria and ceria−zirconia desulfurization sorbents containing up to 20 mol % ZrO 2 were prepared using a coprecipitation method. XRD analysis indicated the formation of solid solutions of ZrO 2 in CeO 2 . ZrO 2 addition produced larger specific surface area, improved sintering resistance, and increased the reducibility of the ceria. Desulfurization was studied using a laboratory-scale fixed-bed quartz reactor. Special precautions were taken to minimize interaction between sub-ppmv concentrations of H 2 S with stainless steel and eliminate contamination from residual sulfur in the reactor system. The performance of sorbents containing ZrO 2 was superior to that of ZrO 2 -free sorbents. Product gas concentrations in the range of 0.1−0.2 ppmv H 2 S were achieved during the prebreakthrough period over the temperature range of 600−750 °C. In particular, the duration of the sub-ppmv prebreakthrough period lasted as much as twice as long when the sorbent contained 20 mol % ZrO 2 compared to ZrO 2 -free CeO 2 .