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

The Korean Society of Mechanical Engineers (대한기계학회)
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Numerical Study of the Optimization of Combustion and Emission Characteristics of Air-Staged Combustion in a Pulverized Coal-Fired Boiler

석탄 화력 보일러의 공기 다단공급방식을 통한 연소 및 배기 배출물 특성 최적화에 관한 수치해석 연구

  • Yoon, Min-Ji (School of Mechanical Engineering, Pusan Nat'l Univ.) ;
  • Lee, Byoung-Hwa (School of Mechanical Engineering, Pusan Nat'l Univ.) ;
  • Song, Ju-Hun (School of Mechanical Engineering, RIMT, PC, Pusan Nat'l Univ.) ;
  • Kim, Gyu-Bo (Pusan Clean Coal Center(PC), Pusan Nat'l Univ.) ;
  • Chang, Young-June (School of Mechanical Engineering, RIMT, PC, Pusan Nat'l Univ.) ;
  • Jeon, Chung-Hwan (School of Mechanical Engineering, RIMT, PC, Pusan Nat'l Univ.)
  • 윤민지 (부산대학교 기계공학부) ;
  • 이병화 (부산대학교 기계공학부) ;
  • 송주헌 (부산대학교 기계공학부, RIMT, PC) ;
  • 김규보 (부산대학교 화력발전에너지분석기술센터) ;
  • 장영준 (부산대학교 기계공학부, RIMT, PC) ;
  • 전충환 (부산대학교 기계공학부, RIMT, PC)
  • Received : 2009.10.23
  • Accepted : 2010.04.20
  • Published : 2010.06.01
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Abstract

Air-staged combustion is known to be one of the techniques of NOx reduction. The objective of this study is to determine the optimal ratio of air flow distributed for CCOFA and SOFA; at this optimal ratio, the combustion and exhaust emission characteristics of a pulverized coal-fired boiler are maintained at a satisfactory level. A numerical investigation was performed at various airflow ratios of 16.7/83.3%, 25/75%, 50/50%, 75/25%, and 83.3/16.7%. An inert gas was considered as a substitute for air to isolate the effects of the cooling process and chemical reaction on NOx reduction; during NOx reduction in air-staged combustion, both the effects typically occur simultaneously. The results of our study show that the optimum condition, under which the maximum NOx reduction and highest boiler efficiency can be obtained, corresponds to the equal splitting of the over-fire air between CCOFA and SOFA.

공기다단연소는 석탄화력발전에서 NOx을 저감하기 위한 기술 중에 하나로 잘 알려져 있다. 본 연구에서는 미분탄 보일러에 공기다단연소를 적용하여 현 수준을 유지하면서도 NOx 저감을 이룰 수 있는 최적의 운전조건을 제안하고자 한다. 공기다단연소를 적용하기 위해 미분단 보일러에 설치된 CCOFA와 SOFA를 통해 공급공기비율을 16.7/83.3%, 25/75%, 50/50%, 75/35% 그리고 83.3/16.7%로 서로 다르게 공급하여 연소 및 배출물질 특성을 연구하였으며, 또한 공기다단연소기술의 적용에 의한 냉각 영향와 재연소반응 영향를 확인하기 위해 동일한 조건에서 공기와 질소를 각각 공급하여 NOx 저감영향을 확인하였다. 본 연구결과를 통해서 CCOFA와 SOFA에 동일한 양을 공급한 공기다단연소조건에서 NOx의 최대저감효과를 확인하였고, 최적의 운전조건을 도출하였다.

Keywords

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