H2O-induced effects on H2S-absorption/COS-release behavior during hot coal gas cleaning with Zn-based sorbents and reducing its negative influence via promoter modification

It is unclear about H 2 O-induced effects on H 2 S-absoprion/COS-release behavior during high-temperature coal gas cleaning with Zn-based sorbents. This work aims at clarifying the aforementioned effect. The results reveal that the presence of 5–10   vol% H 2 O reduces the sulfur capacity of sorbents by 41–55%, while also decreasing the amount of released COS before H 2 S-breakthrough ( A-COS BT ) by 97%–99%. For wet coal gas desulfurization, the CO-H 2 S reaction accounts for nearly all of the COS released, while the contribution from the CO 2 -H 2 S reaction is negligible. Both Ni- and Ce-doping decrease A-COS BT of sorbents by 85%–89% and 92%–94%, respectively. Moreover, Ni-doping enhances the H 2 S-uptake capacity of sorbents by 32%–103%, which is mainly ascribed to the weakening of Zn-O bond. The performance of the Ni-Ce co-doped desulfurizer lies between those of the sorbents doped solely with Ni and Ce, respectively. Furthermore, co-doped sorbents could maintain 82%–92% of initial sulfur capacity and strong ability of inhibiting COS-formation during multiple sulfidation-regeneration cycles. It provides new insights for H 2 O-induced effects on H 2 S-absorption/COS-release behavior during hot coal gas cleaning.