Characterization and Reuse Investigation on Scrapped V2O5-WO3/TiO2Catalysts Operated in Various Industrial Flue Gases for NH3-SCR Reactions

The three scrapped industrial V2O5-WO3/TiO(2)catalysts, which had operated in three coal-fired power plants with various flue gas conditions in China, were collected and characterized by XRF, XRD, SEM, and XPS to analyze their deactivation mechanisms, with the complexities of various industrial flue gases from coal combustion considered. Then one scrapped industrial catalyst was selected as the carrier to prepare a new catalyst by adding Mn, Ce, and Cr species, for SCR reactions in flue gas with as well as without SO(2)at much wider temperature range. Results showed that the content of TiO(2)did not change and the structure kept still, further illustrating that the scrapped catalysts could be utilized as the carrier in the new catalyst manufacturing process. The SO(2)in flue gas indeed increased the V4+/V(5+)ratio on the catalyst surface, moreover, the alkaline earth metal oxides such as BaO and CaO contributed to more sulfates depositing on the catalyst surface, increased the ratios of S6+/S(4+)and O-alpha/O-beta. For the new Mn-Ce-Cr catalyst carried on the scrapped industrial catalyst, it showed high SCR activities at a wider temperature range of 170 to 370 degrees C but low resistance for SO(2)poisoning, indicating that it could be further developed and utilized for SCR process of boilers burning natural gas or biomass. [GRAPHICS] .