Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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The Effect of Pore Structure of Zeolites on their Product Distribution and Deactivation in the Catalytic Cracking of n-Octane

n-옥탄의 촉매 분해반응에서 제올라이트의 세공구조가 생성물 분포와 활성저하에 미치는 영향

  • Min, Byung Goo (School of Applied Chemical Engineering and the Center for Functional Nano Fine Chemicals, Chonnam National University) ;
  • Lee, Jae Youl (School of Applied Chemical Engineering and the Center for Functional Nano Fine Chemicals, Chonnam National University) ;
  • Song, Yo Soon (Institute for Catalysis Research, Chonnam National University) ;
  • Seo, Gon (Institute for Catalysis Research, Chonnam National University)
  • 민병구 (전남대학교 응용화학공학부, 기능성 나노 신화학소재 사업단) ;
  • 이재열 (전남대학교 응용화학공학부, 기능성 나노 신화학소재 사업단) ;
  • 송요순 (전남대학교 촉매연구소) ;
  • 서곤 (전남대학교 촉매연구소)
  • Received : 2007.06.21
  • Accepted : 2007.07.04
  • Published : 2007.12.31
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Abstract

The catalytic cracking of n-octane over FER, MFI, MOR and BEA zeolites was studied by the protolytic cracking mechanism in order to understand the effect of pore structure of zeolites on their product composition and deactivation. The selectivities for $C_3$ and $C_3{^=}$ were high over the zeolites with medium pores due to additional cracking, while those for $C_4$ and $C_4{^=}$, the initial products, were high over the zeolites with large pores. MFI zeolite showed slow deactivation due to small carbon deposit, while FER zeolite with small pores deactivated rapidly with severe carbon deposit. The deactivation of BEA zeolite was slow even with a large amount of carbon deposit, but MOR zeolite showed a rapid deactivation even with a small amount of carbon deposit. The conversion measured along with the time on stream on these zeolite catalysts was simulated by a mechanism based on the simplified reaction path of n-octane cracking and the deactivation related to the pore blockage by carbon deposit.

FER, MFI, MOR, BEA 제올라이트 촉매에서 n-옥탄의 분해반응을 양성자 분해반응(protolytic cracking mechanism) 기구로 해석하여 제올라이트의 세공구조가 생성물 분포와 활성저하에 미치는 영향을 고찰하였다. 세공이 작으면 분해반응이 많이 진행되어 $C_3$와 $C_3{^=}$가 주로 생성되나, 세공이 큰 제올라이트에서는 초기 생성물인 $C_4$와 $C_4{^=}$가 주로 생성된다. MFI 제올라이트에서는 탄소 침적이 억제되어 활성저하가 느리나, FER 제올라이트에서는 탄소가 많이 침적되어 촉매 활성이 빠르게 저하되었다. BEA 제올라이트에서는 탄소가 많이 침적되어도 활성저하가 느리나, MOR 제올라이트에서는 탄소가 조금만 침적되어도 활성저하가 빨랐다. n-옥탄 분해반응의 기구를 단순화하고 탄소 침적에 의한 세공 차폐 정도를 활성저하와 연관지어 반응시간에 따른 전환율 저하 과정을 모사하였다.

Keywords

Acknowledgement

Supported by : 교육인적자원부

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