Effect and mechanism analysis of calcination temperature on the sulfidation behaviors of iron-manganese based sorbents in hot coal gas

The calcination temperature is one of the main operation parameters needed to be regulated during the process of preparing sorbents.The reduction and sulfidation behaviors of 7F3M series mixed metal oxides sorbents with Fe/ Mn atomic ratio of 7 ∶ 3 were investigated,and the properties of pore structure and the forms of active components were characterized in this paper.The effects of calcination temperature on the special surface area,pore volume,and the forms and amounts of active component of Fe-Mn mixed oxides sorbent prepared were discussed.In addition,the relation between these effects and the capacities of sorbent removing H2S from hot coal gas was also analyzed under the conditions of different space velocity and sulfidation temperature.The results show that the specific surface area and pore volume of sorbent increase with the increase of calcination temperature,and they reach a maximum value at 600 ℃.The sintering phenomenon on the surface of sorbent occurs when the calcination temperature continuously increases,which makes the specific surface area and pore volume of sorbent reduce sharply.The sulfidation temperature has a strong influence on the desulfurization capacity of sorbents through the reduction of sorbent and formation of Fe3O4 by H2 and CO contained in sulfidation gas.The Fe3O4 in sorbent is the optimal active species for the desulfurization of sorbent in hot coal gas and its amount can be adjusted by the sulfidation temperature and calcination temperature.The 7F3M600 sorbent has the best sulfidation performances at 500 ℃ and the space velocity of 2 000 h-1.The desulfurization rate of sorbent can reach over 99% and sustain for more than 30 h,in which the sulphur capacity of sorbent is up to 45.56 gS/100 g sorbent.