Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Effect of Precipitation on Operation Range of the CO2 Capture Process using Ammonia Water Absorbent

암모니아수 흡수제를 이용한 이산화탄소 제거 공정에서 침전생성이 조업영역에 미치는 영향

  • You, Jong Kyun (Department of Chemical and Biomolecular Engineering, KAIST) ;
  • Park, Ho Seok (Department of Chemical and Biomolecular Engineering, KAIST) ;
  • Hong, Won Hi (Department of Chemical and Biomolecular Engineering, KAIST) ;
  • Park, Jongkee (Chemical Process Research Center, KIER) ;
  • Kim, Jong-Nam (Chemical Process Research Center, KIER)
  • 유정균 (한국과학기술원 생명화학공학과) ;
  • 박호석 (한국과학기술원 생명화학공학과) ;
  • 홍원희 (한국과학기술원 생명화학공학과) ;
  • 박종기 (한국에너지기술연구원 화학공정연구센터) ;
  • 김종남 (한국에너지기술연구원 화학공정연구센터)
  • Received : 2006.01.18
  • Accepted : 2007.01.11
  • Published : 2007.06.30
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Abstract

Ammonia water was investigated as a new absorbent of the chemical absorption process for the removal of $CO_2$ in flue gas. The suitable range of ammonia water concentration and $CO_2$ loading ($mol\;CO_2/mol\;NH_3$) were decided in the point of view of $CO_2$ absorption capacity and $NH_4HCO_3$ precipitation. The absorption capacity of $CO_2$ and the precipitation of $NH_4HCO_3$ in liquid phase were calculated by the Pitzer model for electrolyte solution. The $CO_2$ absorption capacity of the ammonia water over $5\;molNH_3/kgH_2O$ was higher than that of conventional amine absorbent. The $CO_2$ loadings where precipitation occurred were decided at various absorbent concentrations. Theses values were higher than 0.5 in the concentration range of $5-14\;molNH_3/kgH_2O$ at 293, 313 K. The absorber for the removal of $CO_2$ in flue gas could be operated without $NH_4HCO_3$ precipitation by using high concentration of ammonia water below these $CO_2$ loading values. The optimum temperature of the ammonia water absorbent for removal of $CO_2$ in flue gas was 297-312 K depending on the concentration of ammonia water.

배가스 이산화탄소 처리를 위한 화학적 흡수공정의 새로운 흡수제로서 암모니아수의 적용 가능성을 고찰하였다. 이산화탄소 흡수용량과 침전 발생의 관점에서 적합한 암모니아수 흡수제 농도와 $CO_2$ 부하(loading, $molCO_2/molNH_3$)를 결정하였다. 이를 위하여 전해액에 대한 Pitzer 모델을 이용하여 암모니아 흡수제 농도에 따른 흡수용량과 침전 발생여부를 계산하였다. $5\;molNH_3/kgH_2O$ 이상의 암모니아수 흡수제를 사용하여 기존 아민류 흡수제 이상의 흡수용량은 얻을 수 있었다. 각 암모니아 흡수제 농도에서 $NH_4HCO_3$ 침전의 발생으로 인하여 조업이 제약되는 $CO_2$ 부하를 구하였다. $5{\sim}14\;molNH_3/kgH_2O$의 암모니아 흡수제는 293, 313 K에서 $CO_2$ 부하 0.5 이상에서 침전이 발행하였다. 침전 생성 $CO_2$ 부하값 이하로 흡수탑을 조업함으로써 고농도 암모니아 흡수제가 배가스 $CO_2$ 처리 공정에 사용될 수 있음을 알 수 있었다. 흡수용량과 침전발생을 고려하여 배가스 이산화탄소 처리를 위한 흡수제 최적온도는 암모니아수 농도에 따라 297~312 K이었다.

Keywords

References

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