Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Characteristics of Aqueous Ammonia-CO2 reaction at Regeneration Condition of High Temperature and Pressure

고압고온 재생조건에서의 암모니아수-CO2 반응특성

  • Kim, Yun Hee (Greenhouse Gas Research Center, Korea Institute Energy Research) ;
  • Yi, Kwang Bok (Greenhouse Gas Research Center, Korea Institute Energy Research) ;
  • Park, Sung Youl (Greenhouse Gas Research Center, Korea Institute Energy Research) ;
  • Ko, Chang Hyun (Greenhouse Gas Research Center, Korea Institute Energy Research) ;
  • Park, Jong-Ho (Greenhouse Gas Research Center, Korea Institute Energy Research) ;
  • Beum, Hee Tae (Greenhouse Gas Research Center, Korea Institute Energy Research) ;
  • Han, Myungwan (Department of Chemical Engineering, Chungnam National University) ;
  • Kim, Jong-Nam (Greenhouse Gas Research Center, Korea Institute Energy Research)
  • 김윤희 (한국에너지기술연구원 온실가스연구단) ;
  • 이광복 (한국에너지기술연구원 온실가스연구단) ;
  • 박성열 (한국에너지기술연구원 온실가스연구단) ;
  • 고창현 (한국에너지기술연구원 온실가스연구단) ;
  • 박종호 (한국에너지기술연구원 온실가스연구단) ;
  • 범희태 (한국에너지기술연구원 온실가스연구단) ;
  • 한명완 (충남대학교 화학공학과) ;
  • 김종남 (한국에너지기술연구원 온실가스연구단)
  • Received : 2009.11.18
  • Accepted : 2009.12.20
  • Published : 2010.04.30
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Abstract

In the field of the $CO_2$ absorption process using aqueous ammonia, the effects of regeneration pressure and temperature on $CO_2$ absorption performances of the aqueous ammonia were investigated. The absorbents were prepared by dissolving ammonium carbonate solid in water to grant the resulted solution 0.5 $CO_2$ loading ($mol\;CO_2/mol\;NH_3$) and various ammonia concentration (14, 20, 26 and 32 wt%). As-prepared absorbents were regenerated at high pressure and temperature (over $120^{\circ}C$ and 6 bar) before the absorption test. The absorption test was carried out by injecting the simulated gas that contains 12 vol% of $CO_2$ into a bubbling reactor. The introduction of 26 wt% of the ammonia concentration for $CO_2$ absorption test resulted in the higher absorption capacities than other experimental conditions. In particular, when the absorbents with 26 wt% of the ammonia were regenerated at $150^{\circ}C$ and 14 bar, the highest absorption capacity, $45ml\;CO_2/g$, was obtained. According to the analysis of absorbents using acid-base titration, the ammonia loss during the regeneration of the absorbents with a fixed ammonia concentration decreased as the regeneration pressure increased, while it increased as the regeneration temperature increased. In the condition of fixed regeneration pressure and temperature, as expected, the ammonia loss increased as the ammonia concentration increased. The measured $CO_2$ loadings and ammonia concentrations of absorbents were compared to the values calculated by Electrolyte NRTL model in Aspen Plus.

암모니아수를 이용한 이산화탄소 흡수분리공정에서 흡수액의 재생조건(온도, 압력)이 이산화탄소 흡수성능에 미치는 영향을 조사하였다. 실험에 사용된 흡수액은 탄산암모늄($(NH_4)_2CO_3$)을 물에 용해시키어 $CO_2$ 로딩($mol\;CO_2/mol\;NH_3$)이 0.5, 용액 내의 암모니아수 농도가 14, 20, 26 및 32 wt%로 되도록 제조하였고, 이산화탄소의 흡수에 앞서 재생압력(6~18 bar)을 조절하면서 $120{\sim}160^{\circ}C$의 온도범위로 제조된 흡수액을 가열하여 재생하였다. 재생된 흡수액을 기포 반응기에 넣고 12 vol%의 $CO_2$를 함유한 기체를 주입하여 흡수반응을 수행하였다. 실험결과 26 wt%의 암모니아수가 대체적으로 $CO_2$ 흡수량이 높았으며, 특히 재생온도가 $150^{\circ}C$, 재생압력이 14 bar일 때의 $CO_2$ 흡수량은 본 연구의 실험조건에서 $45ml\;CO_2/g$ solution으로 가장 높은 값을 보였다. 적정을 통해 재생된 용액을 분석한 결과 재생압력이 높아질수록 암모니아 손실량은 감소하고, 재생온도가 높아질수록 암모니아 손실량이 증가하였다. 또한 암모니아 농도증가에 따라 암모니아 손실량이 비례적으로 증가하였다. Electrolyte NRTL 모델을 사용하여 Aspen Plus에 적용한 결과 실험 데이터와 거의 일치함을 보였다.

Keywords

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