Steam regenerative removal of hydrogen sulfide from hot syngas by a novel tin oxide and yttrium oxide sorbent

A novel H2S sorbent based on SnO2 and Y2O3 is developed by a co-precipitation method for steam regenerative removal of H2S from hot syngas at moderate temperatures (400-500 °C). SnO2-Y2O3 sorbent is stable in a reducing atmosphere (i.e. 500 °C, 50% H2) and achieves a 99.9% H2S removal during successive desulfurization and regeneration cycles. The addition of yttrium to SnO2 decreases the reduction property of SnO2 and no metallic Sn exists in the reducing atmosphere due to the formation of a pyrochlore-type compound, Y2Sn2O7. The SnO2-Y2O3 sorbent has a desulfurization performance deterioration with the increasing calcination temperature. The newly developed SnO2-Y2O3 sorbent can be regenerated by steam at 500 °C. In the eight successive desulfurization and regeneration cycles, SnO2-Y2O3 sorbent has a cyclic breakthrough sulfur capacity of 9 mg/g without significant sulfur capacity loss.