Regeneration Kinetics Of Iron Oxide High Temperature Coal Gas Desulfurization Sorbent

With the development of society and economy,energy resource has become a mainstay of the national economics. The coal,which is and will be the major of China’s energy consumption. However,the mining and direct combustion of coal have lead to serious ecological and environmental pollution problem. With the continuous development and utilization of coal resources,the low rank coal will be the main type of future use of coal resources in China. Therefore,the conversion and utilization of clean coal especially the low rank coal is of great significance to China’s national economy,social development and environmental protection. Due to the high thermal efficiency and low pollution,techniques such as IGCC (integrated gasification combined recycle),FC (fuel cell) and CPG (coal polygeneration) have become the most advanced technologies in research and develop of clean coal conversion and utilization technology nowadays. The removal of sulfide especially at medium or high temperature is vitally important for the above-mentioned technologies. To meet the requirement of industrial application,hot coal gas desulfurization sorbent should have excellent performance in desulfurization and regeneration.This work regard metal oxide Fe2O3 as a high temperature gas desulfurization sorbent,prepared by the precipitation and then were on the TGA and fixed bed reactors carry out the kinetics of regeneration under three different atmospheres (O2, SO2, O2- SO2).The result shows that:①in O2 atmosphere,the reaction product of FeS with oxygen are mainly Fe2O3 and SO2. Based on the non-catalytic gas-solid phase reaction kinetics model (equivalent particle model),on TG and fixed bed reactors,the reaction rate of iron oxide sorbent regeneration to oxygen concentration are first order,the regeneration process of the presence of iron oxide sorbent kinetically controlled transfer step,the initial stage of regeneration control by chemical reaction,as the reaction proceeds,the regeneration process is controlled by the diffusion,kinetic parameters were obtained:the pre-exponential factor of chemical reaction rate constants kso is 0.166m/s,activation energy of chemical reaction Ea is 50.77kJ/mol,the pre-exponential factor of effective diffusion coefficient Deo is 1.06×10-4m2/s,the diffusion activation energy Ep 26.47kJ/mol;the pre-exponential factor of chemical reaction rate constants kso is 0.572m/s, activation energy of chemical reaction Ea is 41.09kJ/mol;the pre-exponential factor of effective diffusion coefficient Deo is 1.77×10-2m2/s, diffusion activation energy Ep is 23.94kJ/mol.②In SO2 atmosphere,the reaction product of FeS with oxygen are mainly Fe3O4 and elemental S. Based on the non-catalytic gas-solid phase reaction kinetics model (equivalent particle model),on TG and fixed bed reactors,the reaction rate of iron oxide sorbent regeneration to oxygen concentration are first order,the regeneration process of the presence of iron oxide sorbent kinetically controlled transfer step,the initial stage of regeneration control by chemical reaction,as the reaction proceeds,the regeneration process is controlled by the diffusion,kinetic parameters were obtained:the pre-exponential factor of chemical reaction rate constants kso is 0.0063m/s,activation energy of chemical reaction Ea is 145.31kJ/mol,the pre-exponential factor of effective diffusion coefficient Deo is 4.38 X 10-3m2/s,the diffusion activation energy Ep 50.73 kJ/mol;the pre-exponential factor of chemical reaction rate constants kso is 0.022m/s, activation energy of chemical reaction Ea is 122.32 kJ/mol;the pre-exponential factor of effective diffusion coefficient Deo is 5.6 X 10-3 m2/s,diffusion activation energy Ep is 39.32kJ/mol.③In SO2-O2 atmosphere,the product is:Fe3O4,Fe2O3,SO2 and elemental sulfur. Under the same experimental conditions,collaborative atmosphere with regeneration was significantly shorter than under the single regeneration atmosphere,an atmosphere that is more conducive to collaborative regeneration. By comparison,the ratio of concentrations in the three groups,2.0%(O2)-33.25%(SO2) synergistic regeneration best, 2.0%(O2)-33.25%(SO2) weight loss of oxygen in the atmosphere is far higher than that 2.0% and sulfur dioxide by weight of the total loss of 33.25%,indicating that the results are not two superimposed regeneration cooperative atmosphere alone regeneration kinetics and thermodynamics compensate each other under the atmosphere between the two results in a synergistic atmosphere is better than the main reason for the regeneration atmosphere.