Korean Chemical Engineering Research

  • 제59권1호
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  • Pages.127-137
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  • 2021
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  • 0304-128X(pISSN)
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  • 2233-9558(eISSN)
한국화학공학회 (The Korean Institute of Chemical Engineers)
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국내 미이용 바이오매스 순환유동층 연소에서 NOx 저감을 위한 air-staging 효과

Air-staging Effect for NOx Reduction in Circulating Fluidized Bed Combustion of Domestic Unused Biomass

  • 윤상희 (한국에너지기술연구원 기후변화연구본부) ;
  • 백건욱 (한국에너지기술연구원 기후변화연구본부) ;
  • 문지홍 (한국에너지기술연구원 기후변화연구본부) ;
  • 조성호 (한국에너지기술연구원 기후변화연구본부) ;
  • 박성진 (한국에너지기술연구원 기후변화연구본부) ;
  • 김재영 (한국에너지기술연구원 기후변화연구본부) ;
  • 서명원 (한국에너지기술연구원 기후변화연구본부) ;
  • 윤상준 (한국에너지기술연구원 기후변화연구본부) ;
  • 윤성민 (한국에너지기술연구원 기후변화연구본부) ;
  • 이재구 (한국에너지기술연구원 FEP융합연구단) ;
  • 김주식 (서울시립대학교 환경공학과) ;
  • 문태영 (한국에너지기술연구원 기후변화연구본부)
  • Yoon, Sang-Hee (Climate Change Research Division, Korea Institute of Energy Research (KIER)) ;
  • Beak, Geon-Uk (Climate Change Research Division, Korea Institute of Energy Research (KIER)) ;
  • Moon, Ji-Hong (Climate Change Research Division, Korea Institute of Energy Research (KIER)) ;
  • Jo, Sung-Ho (Climate Change Research Division, Korea Institute of Energy Research (KIER)) ;
  • Park, Sung-Jin (Climate Change Research Division, Korea Institute of Energy Research (KIER)) ;
  • Kim, Jae-Young (Climate Change Research Division, Korea Institute of Energy Research (KIER)) ;
  • Seo, Myung-Won (Climate Change Research Division, Korea Institute of Energy Research (KIER)) ;
  • Yoon, Sang-Jun (Climate Change Research Division, Korea Institute of Energy Research (KIER)) ;
  • Yoon, Sung-Min (Climate Change Research Division, Korea Institute of Energy Research (KIER)) ;
  • Lee, Jae-Goo (FEP Convergence Research Center, Korea Institute of Energy Research (KIER)) ;
  • Kim, Joo-Sik (Department of Environmental Engineering, University of Seoul) ;
  • Mun, Tae-Young (Climate Change Research Division, Korea Institute of Energy Research (KIER))
  • 투고 : 2020.10.06
  • 심사 : 2020.11.05
  • 발행 : 2021.01.25
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초록

미세먼지 전구체인 질소산화물(NOx)에 대한 대기배출부과금 제도가 2020년부터 국내에 도입 및 시행됨에 따라 이를 저감하기 위한 경제적인 연소기술 개발은 매우 시급한 실정이다. 본 연구에서는 해외 우드펠릿 대체재로서 REC(Renewable Energy Certificates) 확보가 가능한 국내 미이용 산림 바이오매스를 연료로 하여 0.1 MWth급 순환유동층 연소 설비에서 NOx 저감을 위한 air-staging 효과를 고찰하였다. 운전 변수로는 air-staging 적용 유무, 3차 공기 공급 높이(6.4 m, 8.1 m, 9.4 m) 그리고 air-staging 비율(1차 공기:2차 공기:3차 공기=91%:9%:0%, 82%:9%:9%, 73%:9%:18%) 변화이며 운전 변수에 대한 배기가스 내 NO와 CO 농도, 연소로 높이별 온도와 압력 프로파일, 포집된 비산재(fly ash) 내 미연탄소 함량과 연소효율을 분석하였다. 3차 공기를 가장 높은 9.4 m에서 공급한 air-staging 운전 시 NO 농도는 100.7 ppm으로 air-staging을 적용하지 않은 운전 조건(148.8 ppm)보다 32.3% 감소하지만 CO 농도는 오히려 52.2 ppm에서 99.8 ppm으로 91% 증가하였다. 더불어, NO 농도의 저감을 위한 환원영역과 CO 농도의 저감을 위한 산화영역 확보를 위해 3차 공기 공급 높이를 6.4 m로 유지하며 3차 공기 공급량을 늘리고 1차 공기 공급량을 낮춘 air-staging 운전 조건(73%:9%:18%)에서는 NO와 CO 농도가 각각 90.8 ppm과 66.1 ppm으로 air-staging 적용 조건 중 가장 감소되는 것을 확인하였다. 이러한 최적 운전 조건에서 연소효율 역시, air-staging을 적용하지 않은 운전 조건의 연소효율(98.3%) 보다 높은 99.3%임을 확인하였다.

Air emission charge for nitrogen oxide as a precursor of fine dust has been introduced and implemented within the country from 2020. Therefore, the development of economical combustion technology for NOx reduction has got more needed urgently. This study investigated the air-staging effect as a way to reduce the NOx during combustion of domestic unused forest biomass, recently possible to secure REC (Renewable Energy Certification) as a substitute for overseas wood pellets in a 0.1 MWth circulating fluidized bed combustion test-rig. Operating conditions were comparison with and without air-staging, the supply position of tertiary air (6.4 m, 8.1 m, 9.4 m in the combustor) and variation of air-staging ratio (Primary air:Secondary air:Tertiary air=91%:9%:0%, 82%:9%:9%, 73%:9%:18%). NO and CO concentrations in flue gas, profiles of temperature and pressure at the height of the combustion, unburned carbon in sampled fly ash and combustion efficiency on operating conditions were evaluated. As notable results, NO concentration with air-staging application under tertiary air supply at 9.4 m in the combustor reduced 100.7 ppm compared to 148.8 ppm without air-staging while, CO concentration increased from 52.2 ppm without air-staging to 99.8 ppm with air-staging. However, among air-staging runs, when tertiary air supply amount at 6.4 m in the combustor increased by air-staging ratio (Primary air:Secondary air:Tertiary air=73%:9%:18%), NO and CO concentrations decreased the lowest 90.8 ppm and 66.1 ppm, respectively. Furthermore, combustion efficiency at this condition was improved to 99.3%, higher than that (98.3%) of run without air-staging.

키워드

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