Study On Filter Catalytic Coupled Denitration Of Modified Porous Ceramic Membrane

This research targeted the emissions of NO_x and dust in the FCC regeneration flue gas.The ceramic membrane was used as the carrier to support the SCR catalyst component to achieve the purpose of filtering and catalytic coupling denitrification,and we mainly developed a new type of efficient and high selective vanadium-free catalyst component.Conclusions of this study are as follows:(1)Research of new vanadium-free SCR catalysts was conducted.The surface modification of HSiW significantly improved the SCR performance of CeO₂.10%HSiW/Ce reached 90%NO conversion at 240? and maintained 99%N₂ selectivity.HSiW was well dispersed on the surface of CeO₂ with a Keggin structure by XRD,Raman and BET characterization,which mainly improved the the amount of Br?nsted acid sites to promote the adsorption of NH₃ according to NH₃-TPD.At the same time,with the help of H₂TPR and XPS,HSiW adjusted the amount of surface oxygen vacancies and improved N₂ selectivity at high temperatures.The in-situ DRIFT experiment indicated that E-R mechanisms dominated the SCR reaction.(2)Sb was dopted to further improve the low temperature SCR activity.HSiW/Ce5Sb1 showed improved low-temperature NO conversionand reduced N₂ selectivity at high temperature.Sb doption made the structure of the catalyst more amorphous by the characterization of XRD and Raman.At the same time,more Ce³⁺and surface adsorbed oxygen were formed in the catalyst through the electron induction according to the XPS and H₂-TPR results,which improved the redox properties of the catalyst and didn't affect the acid sites of the catalyst itself by the NH₃-TPD results.Through the in-situ DRIFT experiment,the NO_x species activated by the catalyst have increased significantly,which promoted the L-H reaction.(3)Study on coupling denitration of modified porous ceramic membrane.The HSiW/Ce catalyst was loaded into the porous ceramic membrane by multiple vacuum impregnation methods to obtain HSiW/Ce modified ceramic membrane.The catalyst gived the ceramic membrane excellent SCR catalytic performance,and the NO removal efficiency was continuously improved with the increase of the load,it can reach 90%conversion at 250?.Compared with the traditional VW/Ti catalyst,HSiW/Ce modified ceramic membrane has significantly better SCR performance.XRD,BET,Raman and SEM were used for characterization,the supported catalyst entered the internal pores of SiC,and a certain degree of agglomeration occurred,which slightly blocked the pores.