Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Phosphorus Modified Co/Al2O3 Fischer-Tropsch Catalyst for a Slurry Phase CSTR with Enhanced Hydrothermal and Mechanical Stability

수열특성 및 기계적 안정성의 개선으로 슬러리상 CSTR에 적합한 P 첨가 알루미나 기반의 Fischer-Tropsch 합성용 코발트 촉매

  • Jung, Gyu-In (Research Center for Green Catalysis, Korea Research Institute of Chemical Technology) ;
  • Ha, Kyoung-Su (Research Center for Green Catalysis, Korea Research Institute of Chemical Technology) ;
  • Park, Seon-Ju (Research Center for Green Catalysis, Korea Research Institute of Chemical Technology) ;
  • Kim, Du-Eil (Research Center for Green Catalysis, Korea Research Institute of Chemical Technology) ;
  • Woo, Min-Hee (Research Center for Green Catalysis, Korea Research Institute of Chemical Technology) ;
  • Jun, Ki-Won (Research Center for Green Catalysis, Korea Research Institute of Chemical Technology) ;
  • Bae, Jong-Wook (Department of Chemical Engineering, Sungkyunkwan University) ;
  • Kang, Yong (School of Chemical Engineering, Chungnam National University)
  • 정규인 (한국화학연구원 그린화학촉매연구센터) ;
  • 하경수 (한국화학연구원 그린화학촉매연구센터) ;
  • 박선주 (한국화학연구원 그린화학촉매연구센터) ;
  • 김두일 (한국화학연구원 그린화학촉매연구센터) ;
  • 우민희 (한국화학연구원 그린화학촉매연구센터) ;
  • 전기원 (한국화학연구원 그린화학촉매연구센터) ;
  • 배종욱 (성균관대학교 화학공학과) ;
  • 강용 (충남대학교 화학공학과)
  • Received : 2011.09.01
  • Accepted : 2011.09.22
  • Published : 2012.04.01
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Abstract

Phosphorus was incorporated into Co/$Al_2O_3$ catalyst for FTS by impregnating an acidic precursor, phosphoric acid, in ${\gamma}-Al_2O_3$ support to improve the mechanical strength, the hydrothermal stability of the catalyst particle, and the catalytic performance as well. Surface characterization techniques such as FT-IR revealed that $AlPO_4$ phase was generated on the surface of the P-modified catalyst. The addition of phosphorus was found to alleviate the interaction between cobalt and alumina surface, and to increase reducibility of catalyst. The catalytic activity such as $C_{5+}$ productivity and turnover frequency (TOF) was calculated to evaluate catalytic performance. The influence of calcination temperature of the $Al_2O_3$ containing 2 wt.% P on the catalytic performance was also investigated. Through hydrothermal stability test and XRD analysis, the P-modified catalyst had strong resistant to the pressurized and hot $H_2O$. The mechanical strength of the P-modified catalyst was also examined through an in-house fluidized-bed vessel, and it was found that the catalyst fragmentation could be successfully suppressed with P. Taken as a whole, the best performance was shown to be at 1~2 wt.% P in alumina and at the calcination temperature of $500^{\circ}C$.

Fischer-Tropsch 합성용 Co/$Al_2O_3$ 촉매에서 알루미나 지지체에 인산 용액으로 알루미나 표면을 개질하여 촉매적 활성은 물론이고, 기계적 강도와 수열 안정성을 개선하였다. FT-IR과 같은 촉매 표면 분석법을 통하여 P 첨가로 알루미나 표면에 $AlPO_4$ 상이 생성되어 촉매인 코발트와 지지체인 알루미나 사이의 상호작용이 약화되어 촉매의 환원도가 높아졌음을 보였다. 이에 따른 촉매성능을 평가하기 위하여 $C_{5+}$ productivity와 turnover frequency를 계산하였다. 또한, 2 wt.% P 첨가 알루미나를 대상으로 지지체의 소성온도가 촉매활성에 미치는 영향도 살펴보았다. 한편, 고온 가압 하에서 물을 이용하여 P 첨가 알루미나(P-알루미나)를 지지체로 한 촉매의 수열 특성을 살펴보았으며, 실험 전후의 XRD 패턴을 분석함으로써 P 첨가 알루미나 기반 촉매가 수열 안정성이 우수하다는 것을 증명하였다. 뿐만 아니라, 촉매의 기계적 강도를 측정하기 위하여 유동화 반응기를 직접 제작하여 P-알루미나 기반 촉매의 P 함량이 증가할수록 마모도가 감소함을 확인하였다. 촉매 활성, 수열 안정성, 그리고 기계적 강도를 모두 고려하면, 알루미나에 첨가된 P의 함량이 1~2 wt.% 이고, 지지체를 $500^{\circ}C$에서 소성하여 제조한 촉매가 가장 좋은 성능을 보였다.

Keywords

Acknowledgement

Supported by : 한국에너지기술평가원(KETEP)

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