| Catalytic deoxidization was an important method for desulphurization and recovery of sulfur. Also biomass which can be converted into reductive compound of CO, CH4 and H2 through pyrogenation, is kind of potential, affluent and easy accessible fuel and resource. Pyrogenic biomass gas, for the first time, was used to deoxidize sulfur dioxide through catalyst. It was in accordance with the environmental requirement of sustainable development policy.Main contents of pyrogenic biomass gas CO, CH4 were used as reducer to deoxidize SO2 into S through catalyst. Fe, Co, Ni and Mo were impregnated on activated Al2O3 to prepare 13 kinds of catalysts with different metal form and content (MOx/γ-Al2O3, M=Fe,Co,Ni, Mo, l#2#3#FeMo,1#2#3#CoMo,1#2#3#NiMo). Metal content, pretreatment, reactant proportion and specific flow rate were examined to evaluate their influence on the performance of desulphurization of catalyst. Under optimum reaction conditions, simulated pyrogenic biomass gas was used to deoxidize SO2. Also, XRD and SEM were used to identify the substance phase and surface shape. Following results have been found out.(1) When CO was used to deoxidize SO2 through catalyst, catalyst impregnated with double transitional metal element was better than that impregnated with single transitional metal element; the priority order of catalyst was Co-Mo-catalyst > Fe-Mo-catalyst > Ni-Mo-catalyst; quantity of active element influence the activity of catalyst; the highest catalytic activity was found out on l#CoMo; converting efficiency of SO2 can be as high as 91.8%.(2) When CH4 was used to deoxidize SO2 through catalyst, catalyst impregnated with single transitional metal element was better than that impregnated with double transitional metal element with Fe2O3/γ-Al2O3 being the best and MOO/γ-Al2O3 being the worst. Within the 600℃～760℃ temperature range , the priority order of catalyst was Fe2O3/γ-Al2O3 > CO3O4/γ-Al2O3 > NiO/γ-Al2O3 > MOO/γ-Al2O3. And the 760℃～820℃ temperature range, the priority order of catalyst was Fe2O3/γ-Al2O3-catalyst > NiO/γ-Al2O3-catalyst > Co3O4/γ-Al2O3-catalyst > MoO/γ-Al2O3-catalyst.(3) Reaction conditions play an important role on the activity of catalyst.①Pretreatment and sulfuration would dramatically improve the performance of catalyst. ② The higher the specific flow rate was the higher the converting efficiency of SO2 was; the higher the temperature was the lower the the decrease of converting efficiency was. ③There was a obvious influence of reductive gas proportion on activity of catalyst. When CO was used to deoxidize SO2 through catalyst, the optimum gas proportion was CO:SO2=2.0 with converting efficiency being 91.8% at 450℃; When CH4 was used to deoxidize SO2 through catalyst, the optimum gas proportion was CH4:SO2=1.0 with converting efficiency being 99.6% at 820℃.(4) Fe2O3/γ-Al2O3-catalyst was examined through pyrogenic biomass gas with the converting efficiency of SO2 being more than 80%. At low temperature, CO was a little better than pyrogenic biomass gas to be used as reducer to deoxidize SO2; at high temperature pyrogenic biomass gas was a better than CO to be used as reducer to deoxidize SO2.(5) XRD spectroscopy indicated that multi-sulfur was produced during the catalytic deoxidization of SO2 through compound gas. SEM indicated that catalyst after reation was sintered, and particle largen, surface reduction. |
