Improvement of sulfur resistance for SCR catalyst at low temperature by HY-Zeolite mixing

Abstract

For the purpose of developing an SCR catalyst with excellent sulfur resistance at low temperature, vanadia-tungsta catalyst supported on titania (VWTi) has been prepared and then physically mixed with HY-Zeolite. Before mixing HY-Zeolite, VWTi catalysts are prepared by changing the content of V to 5 wt%, 10 wt%, 14 wt% and 18 wt% with 7.7 wt% of W to identify the optimal NO removal performance. The catalyst with 14 wt% of V(VWC) showed the highest NO removal performance. Therefore, physical mixtures of VWC and HY-Zeolite are prepared by mechanical mixing in a ball mill. The mass ratios of VWC and HY-Zeolite in the mixture are 1:0.5, 1:1 and 1:2. The sulfur resistance experiment over the above catalysts is carried out for10 h under SO₂ exposure and characteristics were also analyzed by BET, XRF, SEM and abrasion resistance is measured using jet erosion tester. It is found that the sulfur resistance increased until the mixing ratio of HY-Zeolite and VWC is equal but decreased slightly when the mixing ratio of HY-zeolite doubled. From these results, it is confirmed that it is necessary to select an appropriate mixing ratio in consideration of the sulfur resistance and material cost.