Preparations,Features And Desulfurization Kinetics Of Porous Supported Sorbents For Hot Coal Gas

Hydrogen sulfide(H₂S)in hot coal gas is a highly toxic substance for the damage of equipment pipelines and environmental pollution,which seriously affects the industrial application of coal resource.Hot coal gas desulfurization technology can directly remove H₂S with energy-saving and efficient characteristics,based on the higher requirement for desulfurizer development.Porous loaded metal oxide desulfurizer has the advantages,such as large specific surface area,strong mechanical strength,high utilization efficiency of active component,with respect to the ideal materials for removal of H₂S in coal gas at high-temperature.However,the conventional loaded sorbents on pure silica supports still have the defects of small pore size,low activity and poor stability,especially the slow deactivation rate at high-temperature.In order to overcome the above shortcomings,porous sorbents with non-pure silica carriers were developed,and their desulfurization processes were described with the improved deactivation kinetic model.1.Zinc based spinel desulfurizers loaded onto the structural SAPO-34 zeolites were fabricated successfully with the optimal design.By adjusting the B position of spinel where some Co atoms were substituted by Mn or Fe onto SAPO-34@SBA-15(SS)support,the unsubstituted Zn Co₂/SS sorbent had the strong desulfurization ability because of the little effect of PO₄^3-in the support.The breakthrough sulfur capacity of 50 wt%Zn Co₂/SS sorbent is 138.08 mg g^-1 at 550?,and the small loss of active components occured in five desulfurization-regeneration cycles.The breakthrough sulfur capacity of Zn Co₂/SS at the second time was 70.42%of initial value,owing to zinc evaporation,the presence of high stable sulfide and partial sintering.The relationship of the H₂S concentration variation or sorbent deactivation rate vs.duration time was well described by the improved deactivation kinetic model.2.For the mesoporous hierarchical Ca_xCu_yMn_zO_i/MAS-9 sorbent,MAS-9support with the larger channels provided enough anchoring space for highly dispersed active species.The 50 wt%Ca₃Cu₁₀Mn₈₇O_i/MAS-9 exhibited an excellent breakthrough sulfur capacity of 171.57 mg g^-1 at 800? due to the synergistic stabilization of Ca-Cu-Mn.The kinetic study indicated that its excellent performance was also related to the synergistic effect of the rapid H₂S diffusion and component deactivation.The sulfur capacity loss in six cycles was very small,therefore it has great potential in practical high temperature application.3.An anisotropic 3D(a%Ce-Mn)_yAl_2-yO_x desulfurizer was assembled in the ordered channels of walnut wood.The macropores of(8%Ce-Mn)_1.5Al_0.5O_x were contributed to the rapid diffusion of H₂S.The maximum breakthrough sulfur capacity was 289.79 mg g^-1 at 700?,and the utilization efficiency was 88.42%.The rapid diffusion of feed gas in micro/macropores greatly improved the water resistance and anti-interference ability of 3D(8%Ce-Mn)_1.5Al_0.5O_x under the condition of high concentration of water vapor or reducing gas.The improved deactivation kinetic model can well describe the rapid mass transport in sulfidation process.This study opened a new way for the practical application of microporous 3D desulfurizer derived from walnut wood,which was different from the preparation of conventional loaded sorbents.