Study Of Regeneration Performance And Desulfuazion Kinetics For Zn-Mn-Cu Mixed Metal Oxide Sorbents

Medium and high temperature coal gas desulfurization is regarded as one of the promising clean coal techniques due to its high efficiency and low enviromental pollution. Up to now, the main problems in the implementation of high temperature desulfurization technology are the bad cycle stability of sorbents, the difficult regeneration of sorbents and the serious effects of gas atmosphere. The study of Zn-based sorbent for hot gas desulfurization would be an attractive option due to its high desulfurization efficiency.In this paper, the sorbent Z20M4C6SC was prepared by high-pressure impregnation with semi-coke support and the active components of ZnO, MnO and CuO. The regeneration performances of Z20M4C6SC were studied in the fixed-bed reactor under the oxygen, water vapor and oxygen-water vapor atmosphere respectively. Meanwhile the desulfurization kinetics of Z20M4C6SC sorbent were also investigated in three different atmospheres of H2, CO and H2-CO mixed gas.The results of Z20M4C6SC sorbent regeneration experiments show that the performances of sorbent regeneration presents obvious difference with the change of ambient atmosphere.1) Z20M4C6SC has the good regeneration performance under the oxygen atmosphere, but there exists the sintering phenomenon on the surface of sorbent. The optimal concentration of O2in the gas is4%.2) Water vapor has a certain regeneration function for Z20M4C6SC sorbent, and its regeneration ability enhances with the increase of water vapor concentration in ambient atmosphere. But the main problem in this regeneration condition is that regeneration can’t be carried out thoroughly.3) Z20M4C6SC has very good regeneration performance in the mixed atmosphere4%O2and20%H2O(g) and the sintering of sorbent can be effectively controlled in this regeneration gases. The optimal regeneration temperature is650℃.The results of desulfurization kinetics of Z20M4C6SC sorbent in three different atmospheres of H2-H2S-N2, CO-H2S-N2and H2-CO-H2S-N2show that the equivalent particle model is suitable to the sulfuration reaction of Z20M4C6SC sorbent, which are all mainly controlled by gas diffusion through product layer, especially the reaction atmosphere without H2. Ea is respectively2.4859kJ/mol,6.0906kJ/mol,6.2297kJ/mol at the control region of desulfurization reaction, and Ep is respectively6.717712kJ/mol,31.8725kJ/mol,9.3886kJ/mol at the control region of diffusion through the reacted layers in the gases containing39%H2,33%CO,39%H2and33%CO.