Effects of active component on hydrolysis efficiency and desulfurization efficiency of carbonyl sulfur
Front-end fine desulphurization technology of blast furnace gas has become the focus of current research,and the key point is to develop low-temperature,high-activity and long-life catalyst for the hydrolysis of organic sul-fur(mainly carbonyl sulfur COS).Activated carbon(AC)-based catalyst was prepared by co-impregnation method with AC as the carrier and metal oxide as the active component.Furthermore,the effects of the type and the loading amount of metal oxide on the desulfurization ratio and COS hydrolysis ratio of the catalyst were experimentally inves-tigated.Simultaneously,the transformation mechanism of sulfide during the desulfurization process was revealed by utilizing modern analysis and testing technology.The results showed that the removal effect of COS by pure AC catalyst is poor,and the desulfurization ratio and the COS hydrolysis ratio were lower than 30%.The desulfuriza-tion property of catalyst can be improved by loading metal oxides.As the loading amount of iron oxide is about 3%,the high-active desulfurization(desulfurization ratio>99%)time is approximately 48 min,and the breakthrough sul-fur capacity is 63.72 mg/g.With increasing the loading amount of iron oxide,the specific surface area,total pore volume,and micropore volume of the catalyst are decreased,and the catalyst still has abundant pore structure.Meanwhile,the desulfurization ratio,COS hydrolysis ratio,and breakthrough sulfur capacity are all increased firstly and then decreased with increasing the iron oxide loading amount.When the loading amount of iron oxide is 16%,the desulfurization performance of the catalyst is better,and the high active desulfurization time and the high active hydrolysis(COS hydrolysis ratio>99%)time are about 78 min,and the breakthrough sulfur capacity reaches 104.21 mg/g.By means of BET,XRD,XPS,and SEM,it was found that under the action of the catalyst,COS is firstly hydrolyzed into H2S,and then H2S is converted into sulfate and elemental sulfur under the action of oxidation functional groups and metal ions,which are attached to the pores of the catalyst,thus the removal of sulfide is realized.
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