成型压力对钛铝基COS水解催化剂催化性能的影响机理OA

The removal of COS from blast furnace gas is essential for the steel industry to meet ultra-low emission requirements.At present,COS hydrolysis catalysts that have been developed are prone to oxygen poisoning and deactivation,have a short service life,and thus cannot meet the requirements of industrial applications.Ti-Al-based(TiO2-Al2O3)COS hydrolysis catalysts were prepared by a dry mixing method and extruded at forming pressures of 10 MPa,19 MPa and 43 MPa,respectively.Under the conditions of 60℃,COS mass concentration of 300 mg/m3,O2 volume fraction of 12%and space velocity of 1000 h-1,the catalytic performances of the catalysts were tested.In addition,N2 adsorption/desorption,MIP,SEM and XPS were employed to investigate the mechanism by which forming pressure affects catalytic performance.The results show that during catalytic hydrolysis,COS diffuses from the external surface of the catalyst through pores to the internal surface,where it is adsorbed and undergoes a hydrolysis reaction with—OH or H2O to produce H2S and CO2.These products then diffuse outward through the pores to the external surface of the catalyst.As the forming pressure increases,the catalyst particles become gradually densified.Microscopically,part of the 100 nm to 1000 nm macropores are compressed and collapsed,forming ultramacropores of 10 μm to 360 μm at the macroscopic scale,which significantly hinders COS adsorption and H2S diffusion.Increased H2S adsorption further leads to oxidation and sulfur deposition on the catalyst surface.The presence of oxygen vacancies can promote oxygen migration,which to some extent enhances COS adsorption and facilitates the diffusion of H2S,thereby partially suppressing sulfur deposition.This study provides a reference for the industrial application of related laboratory research results.