Preparation Of Fe₂O₃/γ-Al₂O₃ And The Study Of Desulfurization And Regeneration

In 1990 s,the formation of three major energy sources with the rapid development of natural gas : natural gas、coal、oil.With the development of human being,the consumption of energy is increasing.This will cause environmental pollution.We must protect the environment while developing the economy,which requires us to develop the clean energy.However,we need to develop the coal for a long period of time because of various factors.We need to develop the coal chemical industry but not the extensive mode,which is clean coal industry.Coal methanol,coal chemical and other traditional coal chemical industry are unable to meet the current development of the country due to overcapacity and environmental pollution.At present,the new coal chemical industry is developing rapidly.In particular,IGCC poly generation technology,IGFC-CC was recognized by the majority of people because of their high utilization,environmental pollution is small.However,the desulfurization and purification of high temperature coal gas after coal gasification is an indispensable part.In this paper,the preparation of high temperature coal gas sorbent by the method of sol-gel was studied.In this experiment,the mesoporous alumina with high specific surfacearea was prepared by using sucrose as template and aluminum nitrate as the aluminum source.The activated alumina was placed in the α-Fe₂O₃ sol,and then the soebent was obtained by steam drying,drying,washing and roasting.The effects of loading,calcination temperature and calcination time on the performance of desulfurizer were investigated,then mixed with blinder to form the desulfurizing agent.The performance of the desulfurizer was evaluated in a fixed bed reactor.The regeneration performance of desulfurizer was studied in SO₂、O₂ and N₂ mixed atmosphere.The effects of regeneration temperature,regeneration space velocity,different ratio on the regeneration performance of desulfurizer were investigated.At last,the best regeneration condition was used for the 5 time vulcanization-regeneration cycle.Characterization analysis of desulfurization before and after the reaction by using XRD,SEM,BET and XPS,we can reach the following conclusion:（1）Using sucrose as the template and aluminum nitrate as the aluminum source,the specific surface area of activated alumina prepared by sol-gel method is high,and the pore volume is large.It can be seen from SEM that the pores are more developed.The strength of the desulfurizer can be improved,and the dispersion of the active component can be improved by using it as a carrier.（2）The preparation conditions were investigated by single factor method.The main contents of the study were as follows: loading,calcination temperature and calcination time.First of all,the load was investigated,respectively,15%（mass fraction）,and 25%,35%,40%,its evaluationin in a fixed bed,taking into account the sulfur content,sulfur content utilization and other factors to determine that the best load is 35%（mass fraction）,the best calcination temperature is about 550℃,the best roasting time is 3h.It can be seen that the main active components of fresh desulfurizer are α-Fe₂O₃ through the characterization of XRD.Main production is Fe1-xS after vulcanization.It can be seen that the specific surface area and pore volume were decreased through the characterization of BET.Sulfur content utilization rate of shaped desulfurizer can reach 78.10%.（3）The desulfurizer was prepared by the best preparation conditions,and then regenerated in a fixed bed.The regeneration atmosphere is sulfur dioxide and oxygen,mainly to investigate the regeneration temperature,regeneration air speed,the effect of different proportions on the regeneration,determine the optimal regeneration conditions through the regeneration rate,weight gain rate and other indicators.The best regeneration temperature is600 ℃,the best regeneration space velocity is 12000h-1,the best ratio:SO₂（4%）+O₂（2%）.Carrying out the 5 vulcanization regeneration cycle by using the best regeneration condition,the sulfur content,specific surface area and pore volume tend to be stable with the increase of the number of cycles.It can be seen that no sulfate formation after regeneration at 600℃ through XRD,XPS.The interaction between Fe₂O₃ and Al₂O₃ is not only of physical nature but also of chemical nature by analyzing the XPS spectrum of Fe 2p.