Clean Technology (청정기술)

The Korean Society of Clean Technology (한국청정기술학회)
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Pollutants Behavior in Oxy-CFBC by Application of In-Furnace deSOx/deNOx Method

순산소 순환유동층에서 로내 탈황 및 탈질법 적용에 따른 오염물질 거동특성

  • Choi, Gyung-Goo (Department of Environmental Machinery, Koera Institute of Machinery & Materials) ;
  • Na, Geon-Soo (Department of Environmental Machinery, Koera Institute of Machinery & Materials) ;
  • Shin, Ji-Hoon (Department of Environmental Machinery, Koera Institute of Machinery & Materials) ;
  • Keel, Sang-In (Department of Environmental Machinery, Koera Institute of Machinery & Materials) ;
  • Lee, Jung-Kyu (Department of Environmental Machinery, Koera Institute of Machinery & Materials) ;
  • Heo, Pil-Woo (Department of Environmental Machinery, Koera Institute of Machinery & Materials) ;
  • Yun, Jin-Han (Department of Environmental Machinery, Koera Institute of Machinery & Materials)
  • 최경구 (한국기계연구원 환경기계연구실) ;
  • 나건수 (한국기계연구원 환경기계연구실) ;
  • 신지훈 (한국기계연구원 환경기계연구실) ;
  • 길상인 (한국기계연구원 환경기계연구실) ;
  • 이정규 (한국기계연구원 환경기계연구실) ;
  • 허필우 (한국기계연구원 환경기계연구실) ;
  • 윤진한 (한국기계연구원 환경기계연구실)
  • Received : 2018.05.23
  • Accepted : 2018.06.15
  • Published : 2018.09.28
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Abstract

Oxy-fuel combustion is considered as a promising greenhouse gas reduction technology in power plant. In this study, the behaviors of NO and $SO_2$ were investigated under the condition that in-furnace $deNO_x$ and $deSO_x$ methods are applied in oxy-fuel circulating fluidized bed combustion condition. In addition, the generation trends of $SO_3$, $NH_3$ and $N_2O$ were observed. For the purpose, limestone and urea solution were directly injected into the circulating fluidized bed combustor. The in-furnace $deSO_x$ method using limestone could reduce the $SO_2$ concentration in exhaust gas from ~403 to ~41 ppm. At the same experimental condition, the $SO_3$ concentration in exhaust gas was also reduced from ~3.9 to ~1.4 ppm. This trend is mainly due to the reduction of $SO_2$. The $SO_2$ is the main source of the formation of $SO_3$. The negative effect of $CaCO_3$ in limestone, however, was also appeared that it promotes the NO generation. The NO concentration in exhaust gas reduced to ~26 - 34 ppm by appling selective non-catalytic reduction method using urea solution. The $NH_3$ concentration in exhaust gas was appeared up to ~1.8 ppm during injection of urea solution. At the same time, the $N_2O$ generation also increased with increase of urea solution injection. It seems that the HNCO generated from pyrolysis of urea converted into $N_2O$ in combustion atmosphere. From the results in this study, the generation of other pollutants should be checked as the in-furnace $deNO_x$ and $deSO_x$ methods are applied.

순산소 연소기술은 화력발전에 적용 가능한 유망한 온실가스 감축 기술로 평가되고 있다. 본 연구는 환경적 관점에서 순환유동층을 활용한 순산소 연소조건에 로 내 탈황 및 탈질법을 적용하여 NO 및 $SO_2$의 거동을 살펴보는 한편, $SO_3$, $NH_3$, 그리고 $N_2O$의 발생 경향도 관측하였다. 이를 위해, 연소로 내 석회석 및 요소수를 투입하였다. 로 내 탈황법은 연소가스 내 $SO_2$ 농도를 ~403에서 ~41 ppm까지 저감하였다. 또한 $SO_3$ 형성의 주원료인 $SO_2$가 저감되면서 연소가스 내 $SO_3$ 농도도 ~3.9에서 ~1.4 ppm까지 감소되었다. 그러나 석회석 내 $CaCO_3$가 NO의 발생을 촉진하는 현상도 관측되었다. 연소가스 내 NO 농도는로 내 탈질법을 적용하여 ~26 - 34 ppm까지 저감되었다. 요소수 투입량 증가에 따라 연소가스 내 $NH_3$ 농도가 증가하여 최대 ~1.8 ppm으로 나타났으며, $N_2O$의 농도도 ~61에서 ~156 ppm까지 증가하였다. $N_2O$ 발생량 증가 현상은 요소수의 열분해 과정에서 생성된 HNCO가 $N_2O$로 전환되어 나타난다. 본 연구의 결과를 통해 로 내 연소가스 세정법을 적용할 경우 $NO_x$ 및 $SO_x$의 저감뿐만 아니라, 다른 오염물질의 발생에 대한 주의가 필요할 것으로 보인다.

Keywords

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