Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Effect of Ash Content on Unburned Carbon and NOx Emission in a Drop Tube Furnace

DTF 를 이용한 석탄 회분 함량에 따른 미연분 및 NOx 배출 특성 연구

  • 김상인 (부산대학교 기계공학부) ;
  • 이병화 (부산대학교 화력발전에너지분석기술센터) ;
  • 안기주 (부산대학교 기계공학부) ;
  • 김만철 ((주)한국남부발전) ;
  • 김승모 (부산대학교 화력발전에너지분석기술센터) ;
  • 전충환 (부산대학교 기계공학부)
  • Received : 2014.02.25
  • Accepted : 2014.08.24
  • Published : 2014.12.01
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Abstract

Four coal sources that had different ash contents were evaluated in a drop tube furnace (DTF). Combustion experiments were conducted by using several sources with different particle sizes and excess air ratios under air-staging conditions to determine the optimized combustion conditions of high-ash coal, with an emphasis on the combustion efficiency and NOx emissions. The results show that the higher ash content results in a large amount of carbon remaining unburned, and that this effect is dominant when the largest particle size is used. Furthermore, the ash content of coal does affect the Char-NOx concentration, which decreases with the particle size. The results of this study suggest that an air-staged system can be useful to reduce the NOx emissions of high-ash coal and that control of the air stoichiometric ratio of the primary combustion zone (SR1) is effective for reducing NOx emissions, especially by considering unburned carbon contents.

본 연구는 고회분탄의 최적화된 연소 조건을 알아보기 위해 회분 함량이 각기 다른 네 종류 석탄의 연소시 배출되는 NOx및 미연분 특성을 알아보았다. 실험은 DTF(Drop Tube Furnace)를 통해서 다양한 입자크기조건 및 공기다단방식을 도입하여 수행하였다. 결과로 회분의 함량이 증가할수록 미연분이 증가하며, 입자크기가 증대될수록 미연분에 대한 회분의 영향이 명확해짐을 확인하였다. 또한, 회분의 함량이 증가할수록 Char-NOx가 감소하며, 입자크기가 감소할수록 NOx의 배출이 감소하는 것을 확인하였다. 본 연구는 고회분탄의 NOx를 저감하는 방법으로 공기다단방식의 적용을 제안하며 전단 연소 영역의 공기과잉률 변화를 통한 최적화된 연소조건을 제시하였다.

Keywords

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