Activity and characterization of Rh/Al_2O_3 and Rh-Na/Al_2O_3 catalysts for the SCR of NO with CO in the presence of SO_2 and HC1

摘要

SO_2 and HCl are major pollutants emitted from waste incineration processes. Both pollutants are difficult to remove completely and can enter the catalytic reactor. In this work, the effects of SO_2 and HC1 on the performance of Rh/Al_2O_3 and Rh-Na/Al_2O_3 catalysts for NO removal were investigated in simulated waste incineration conditions. The characterizations of the catalysts were analyzed by BET, SEM/EDS, XRD, and ESCA. Experimental results indicated the 1%Rh/Al_2O_3 catalyst was significantly deactivated for NO and CO conversions when SO_2 and HO coexisted in the flue gas. The addition of between 2 and 10 wt.% Na promoted the activity of the 1%Rh/Al_2O_3 catalyst for NO removal, but decreased the CO oxidation and BET surface area. The catalytic activity for NO removal was inhibited by HC1 as a result of the formation of RhCl_3. Adding Na to the Rh/Al_2O_3 catalyst decreased the inhibition of SO_2 because of the formation of Na_2SO_4, which was observed in the XRD and ESCA analyses. SEM mapping/EDS showed that more S was residual on the surface of the Rh-Na/Al_2O_3 catalyst than Cl.