Effect Of Texture On The Property Of High Temperature Coal Gas Desulfurization Sorbent

Coal is a main fossil energy source and chemical raw material. Not being exploited and used correctly, it will, however, cause serious environmental pollution which is especially evident in China. Therefore, controlling and reducing the adverse effect on environmental are a great requirement of sustainable development in China, and higher efficiency and cleaner conversion of coal is an important way to realize it. Integrated gasification combined cycle (IGCC) power system is the most promising clean-up coal using technology in twenty first century, among which hot gas desulfurization is one of the key technologies.A great deal of studies on high temperature coal gas desulfurization have been made and obtained some important results at home and abroad. But industrialization of this technology has not been realized, and the main obstacle is the decrease of durability of desulfurizer. Looking for the cause of stability decrease by researching active compositions is the present hot spot. However, there are few studies on how the texture affects the decrease of desulfurizer, and so this thesis aims at researching effect of texture on the properties of high temperature coal gas desulfurization sorbent.In this paper, the sorbents for hot coal gas desulfurization were prepared by using red-mud as activate component from steel factory, different binders and pore structure modifier distribution. The sorbents were subjected three sulfidation/regeneration cycles in a fixed-bed reactor at simulated coal gas composition, and the properties were characterized by means of conventional techniques, such as TG,XRD and mercury poresizer. Fractal dimension was used to correlate the texture and the property of desulfurizer. Main results are as follows:Mixed clay is the best binder among mixed clay, kaolinite, bentonite and high temperature cement, which were used as binder in preparation of high temperature coal desulfurization sorbent.Regeneration conditions influence the performance of the desulfurizer. The regeneration of sorbent prepared in the temperature of 700℃and in the gas of 2% O₂ can keep better desulfurization activity for regenerated sorbent.The content of the pore-making agent in the sorbents has the most suitable range.Adopting different pore-making agent gives different texture for sorbent prepared. Sulfidation mostly took place in pores, which radium is between 500(?) and 5000(?). Sulfur capacity increased with the increase of pore volume in range of above pore radium. The sulfur capacity is influenced by specific surface area, pore volume, pore radium and pore distribution. When the pore volume is certain, fractal dimension increases with the increase of specific surface area. The sulfur capacity increases with fractal dimension reducing.The concentration of COS increased accompanying with concentration of H₂S outlet.The main phases are Fe₂O₃ in fresh sorbents, and in reduction atmosphere, Fe₂O₃ is converted to Fe₃O₄ and FeO. In the sulfided samples the most significant phases are Fe_1-xS, Fe₇S₈ and FeS.