A study of hydrocarbon SCR(selective catalytic reduction) on Ag/γ-Al2O3 catalyst

Ag/γ-Al2O3 촉매상에서 탄화수소-SCR(Selective Catalytic Reduction) 연구

  • Kim, Moon-Chan (Department of Environmental Engineering, Cheongju University) ;
  • Lee, Cheal-Gyu (Department of Environmental Engineering, Cheongju University)
  • 김문찬 (청주대학교 이공대학 환경학부) ;
  • 이철규 (청주대학교 이공대학 환경학부)
  • Received : 2004.09.30
  • Accepted : 2005.03.03
  • Published : 2005.04.25

Abstract

Removal of NO contained in automobile exhaust gas was accomplished by the non-selective catalyst reduction method. The catalysts were prepared through loading of a specific amount of Ag into ${\gamma}-Al_2O_3$. The conversion of $NO_x$ was studied by varying the temperatures, $O_2$ concentrations and $SO_2$ concentrations for the prepared catalysts. The influence of the structure of catalyst to $NO_x$ conversion was followed through the analysis of the physical properties of the prepared catalysts. Experiments were conducted on each of the catalysts by varying the reaction conditions to find an optimum condition. The catalyst $Ag/{\gamma}-Al_2O_3$ shows a highest $NO_x$ conversion when the Ag content was 2 wt% and a reaction temperature of about $450^{\circ}C$. and after conducting the experiments, samples of before and after experiments analyzed using XRD, XPS, TPR, and UV-Vis DRS experiments. The result indicated that when Ag oxide content could not be maintained well at high temperatures $NO_x$ conversion decreased.

본 연구에서는 자동차의 배출가스중에 포함된 NO를 비선택적 촉매환원법으로 환원시켜 제거하기 위하여 Ag의 함량을 여러 가지로 달리하여 ${\gamma}-Al_2O_3$에 담지한 촉매를 제조하였고, 제조한 촉매에 대하여 온도, 산소농도, 아황산가스농도의 변화에 따른 $NO_x$의 전환율에 대하여 연구하였다. 또한 제조한 촉매의 물성분석을 통하여 촉매의 상태와 $NO_x$의 전환율과의 관계를 알아보았다. 제조한 각각의 촉매에 대하여 반응조건을 여러 가지로 달리하여 반응실험을 한 결과 $Ag/{\gamma}-Al_2O_3$ 촉매는 Ag의 함량이 2 wt%일 때, 그리고 반응온도가 약 $450^{\circ}C$일 때 가장 높은 $NO_x$ 전환율을 나타냈다. 반응실험 전 후의 촉매에 대하여 X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Temperature Programmed Reduction (TPR), Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS)등의 분석 결과와 반응실험 결과를 비교하여 볼 때 Ag의 산화상태가 잘 유지되지 못하여 고온에서는 $NO_x$ 전환율이 낮아지는 것으로 나타났다.

Keywords

References

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