수소 풍부 환원제 변화가 Co-Pt/ZSM5 촉매를 사용하는 탈질 HC-SCR 반응에 미치는 영향

Abstract

HC-SCR was conducted over Co-Pt/ZSM5 catalyst coated over 200 cpsi cordierite in the condition of atomspheric pressure and 200℃-500℃. Weight ratio of Co/Pt determined from EDX analysis was 8/2, which was almost equal to the weight ratio at preparation step . XPS showed that nitrates within cobalt precursor and chlorine withn Pt precursor were removed. TEM result demonstrated that crystallite size of cobalt and Pt was under 5nm. Among these tested hydrocarbon reductants, isobutane (i-C4H10) showed the highest de-NOx yield of 80% under the condition of the mole ratio of reductant/NOx =1.0 at 180℃. De-NOx yield from HC-SCR was increased as the carbon number of hydrocarbon reductant was increased. The decrease of bonding energy between C and H of HC reductant played a role to increase of de-NOx yield, which indicated that the dissociation step of C-H bond of hydrocarbon molecule might be the rate determining step of HC-SCR. The increase of oxygen concentration in the feed resulted in the decrease of de-NOx yield but the increase of CO and N2O yield.