Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Characteristics of NO Oxidation Using NaClO2

NaClO2를 이용한 NO 산화 특성

  • Lee, Kiman (Environment Research Department, Research Institute of Industrial Science & Technology (RIST)) ;
  • Byun, Youngchul (School of Environmental Science and Technology, Pohang University of Science and Technology (POSTECH)) ;
  • Koh, Dong Jun (Environment Research Department, Research Institute of Industrial Science & Technology (RIST)) ;
  • Shin, Dong Nam (Environment Research Department, Research Institute of Industrial Science & Technology (RIST)) ;
  • Kim, Kyoung Tae (Environment Research Department, Research Institute of Industrial Science & Technology (RIST)) ;
  • Ko, Kyoung Bo (School of Environmental Science and Technology, Pohang University of Science and Technology (POSTECH)) ;
  • Cho, Moohyun (School of Environmental Science and Technology, Pohang University of Science and Technology (POSTECH)) ;
  • Namkung, Won (School of Environmental Science and Technology, Pohang University of Science and Technology (POSTECH)) ;
  • Mok, Young Sun (Department of Chemical of Biological Engineering, Jeju National University)
  • 이기만 (포항산업과학연구원 환경연구실) ;
  • 변영철 (포항공과대학교 환경공학과) ;
  • 고동준 (포항산업과학연구원 환경연구실) ;
  • 신동남 (포항산업과학연구원 환경연구실) ;
  • 김경태 (포항산업과학연구원 환경연구실) ;
  • 고경보 (포항공과대학교 환경공학과) ;
  • 조무현 (포항공과대학교 환경공학과) ;
  • 남궁원 (포항공과대학교 환경공학과) ;
  • 목영선 (제주대학교 생명화학공학과)
  • Received : 2008.02.29
  • Accepted : 2008.04.23
  • Published : 2008.10.31
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Abstract

The characteristics of NO oxidation using sodium chlorite ($NaClO_2$) powder have been investigated by a flow type packed-bed reactor, where the reaction temperature and the space velocity are varied in the range of $20{\sim}230^{\circ}C$ and $0.4-2.2{\times}10^5hr^{-1}$, respectively, and the simulation gas mixtures are composed of NO (0~200 ppm), $NO_2$ (0-200 ppm), $O_2$ (0~15%) and $H_2O$ (0~15%) within $N_2$ balance. It has been found that the oxidation efficiency of NO depends greatly on the reaction temperature, exhibiting the existence of critical reaction temperature at about $170^{\circ}C$ where the oxidation efficiency of NO is maximized and then abruptly decreased with further increase of reaction temperature, resulting in being negligible over $190^{\circ}C$. Such a behavior in the oxidation efficiency has been originated from the phase transition of $NaClO_2$ at about $170^{\circ}C$ to form $NaClO_3$, and NaCl which are chemically inactive toward the oxidation of NO. The chemical reaction of NO with $NaClO_2$ has been observed to produce $NO_2$, ClNO and $ClNO_2$, whereas that of $NO_2$ only OClO species. Additionally, we have also observed that the introduction of $O_2$ and $H_2O$ has little influence on the oxidation of NO.

고정층 반응기에 충진한 $NaClO_2$에 의한 NO 산화특성을 온도와 가스조건 그리고 공간속도 등을 변화시켜가며 알아보았다. $NaClO_2$와 NO의 반응은 온도에 크게 의존함을 알 수 있었다. $110^{\circ}C$까지 $NaClO_2$와 NO의 반응성은 천천히 증가하고 그 이후의 온도에서는 빠르게 증가하였으며 $170^{\circ}C$ 부근에서 가장 높은 반응성을 나타내는 것을 확인하였다. 하지만 $190^{\circ}C$ 이상의 온도에서는 $NaClO_2$가 NaCl, $NaClO_3$, 상전이하여 NO와의 반응성이 나타나지 않았다. $NaClO_2$와 NO 반응의 주 생성물은 $NO_2$였으며 가스상 형태의 ClNO, $ClNO_2$ 등이 부산물로 나타났다. 이는 $NaClO_2$에 의한 NO의 산화물인 $NO_2$와 $NaClO_2$가 반응하여 가스상 부산물인 OClO를 생성하고, 생성된 OClO가 잔류하는 NO를 $NO_2$로 산화시키며 발생되는 Cl에 의한 것임을 확인하였다. 이와 함께 수분 및 산소의 변화는 NO 산화에 주는 영향이 미미하다는 것을 알 수 있었다.

Keywords

Acknowledgement

Supported by : 환경부

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