천연가스복합발전 공정은 일반 석탄 화력발전 공정에 비해 이산화탄소 배출량이 낮아 최근에 발전 플랜트로서 많 은 관심을 받고 있다. 그럼에도 불구하고 이산화탄소 배출을 완전히 억제하기는 어려우므로 이산화탄소 포집공정이 필요하며 본 연구에서는 천연가스복합발전 플랜트에서 발생하는 배기가스 내 낮은 이산화탄소 농도를 고려해 포집 공정을 구성하고 운전조건을 최적화하는 연구를 수행하였다. 최적화 연구를 위해 상용 시뮬레이션 프로그램으로 천 연가스복합발전 공정과 습식 이산화탄소 포집공정이 결합된 전체 공정을 모델링 하였으며, 이를 이용해 다양한 조건 에서 이산화탄소 흡수율, 흡수제 재생율, 천연가스복합발전 공정 내 전력 손실율을 종합적으로 고려한 최적 운전조 건을 도출하였다. 특히 본 연구에서는 기존에 이산화탄소 포집공정에서 포집된 이산화탄소 톤당 에너지 소모량만을 주요 지표로 검토하던 것과 달리, 천연가스복합발전 공정 내 스팀 사용으로 인한 발전효율 저감, 운전조건 변화에 따른 이산화탄소 흡수율 및 흡수제 재생율 변화의 측면도 함께 고려하여 공정 전반의 성능을 종합적으로 고려할 수 있도록 하였다. 결론적으로 재생탑 재비기 온도가 120 ℃가 되었을 때 가장 좋은 결과를 보이는 것으로 나타났으며, 그 원인을 분석하였다.

Natural Gas Combined Cycle(NGCC) recently receives lots of attention as an attractive form of power plants by virtue of its low carbon emission compared with coal-fired power plant. Nevertheless, it also needs carbon capture process since it is difficult to completely suppress carbon emission even for the NGCC. A simulation study has been performed to optimize operating condition of a carbon capture process using MEA considering low partial pressure of carbon dioxide in NGCC emission gas. For accurate optimization, overall process model including both NGCC and the carbon capture process has been built with a simulation software. Then, optimization in which various performance indices such as carbon dioxide absorption rate, solvent regeneration rate and power loss in the NGCC are simultaneously reflected has been done. Especially, it is noticeable that this study focuses on not only the amount of energy consumption but also the absorption and regeneration performance of carbon capture process. The best result considering all the performance indices has been achieved when the reboiler temperature is 120 ℃ and the reason has been analyzed.

NGCC CCS Optimization Power loss Absorption rate Regeneration rate

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