文摘
A new preparation method of zinc oxide (ZnO) sorbents for removing H2S from hot coal gas was explored. High-pressure impregnation with semi-coke as the support and zinc nitrate as the active component precursor was used to prepare Zn-based sorbents (HZnSC). The desulfurization activity of the sorbents was studied in a fixed-bed reactor under the simulated coal gas mixture of CO (33 vol%), H2 (39 vol %), H2O (5 vol %), H2S (300 ppmv), and N2 (balance) at 300鈥?50 掳C. The results show that the desulfurization activity of the HZnSC sorbents is higher than that of the sorbents prepared using atmospheric pressure impregnation. The surface area of the semi-coke expanded from 16.65 to 272.59 m2/g. Nanoscale ZnO was acquired, and the active component was uniformly dispersed on the support with the high-pressure impregnation method, which afforded H2S removal from hot coal gas. HZn20SC (prepared with 20 wt % zinc nitrate solution) reduced H2S from 300 to less than 0.1 ppmv at 300鈥?50 掳C, and its sulfur capacity was 4.5 g of S/100 g of sorbent at 500 掳C. It also maintained good heat stability during three desulfurization/regeneration cycles. The findings suggest that semi-coke with a low surface area can be used as a support of sorbents to remove H2S from hot coal gas using high-pressure impregnation.