Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Analysis of Oxygen Combustion Characteristics of a Low Grade Coal Using IEA-CFBC Model

IEA-CFBC 모델을 이용한 저급탄의 순산소 연소 특성 분석

  • Gwak, You Ra (Department of Mineral resources energy engineering, Chonbuk national university) ;
  • Kim, Ye Bin (Department of Mineral resources energy engineering, Chonbuk national university) ;
  • Keel, Sang In (Environment System Research Division, Korea Institute of Machinery and Materials) ;
  • Yun, Jin Han (Environment System Research Division, Korea Institute of Machinery and Materials) ;
  • Lee, See Hoon (Department of Mineral resources energy engineering, Chonbuk national university)
  • 곽유라 (전북대학교 자원에너지공학과) ;
  • 김예빈 (전북대학교 자원에너지공학과) ;
  • 길상인 (한국기계연구원 환경시스템연구본부) ;
  • 윤진한 (한국기계연구원 환경시스템연구본부) ;
  • 이시훈 (전북대학교 자원에너지공학과)
  • Received : 2018.07.07
  • Accepted : 2018.08.14
  • Published : 2018.10.01
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Abstract

The application of an oxy-combustion circulating fluidized bed combustor (Oxy-CFBC) for low grade coals has recently developed in the world to meet the continuous increase of energy demand and to achieve the reduction of greenhouse gases. Since demo plants for Oxy-CFBC have been developed, the combustion properties of Oxy-CFBC in various operation conditions, such as gas flow rates, combustion temperature, fuel, and so on, should be investigated to develop design criteria for a commercial Oxy-CFBC. In this study, a computational simulation tool for Oxy-CFBC was developed on the basis of the IEA-CFBC (International Energy Agency Circulating Fluidized Bed Combustor) model. Simulation was performed under various conditions such as reaction temperature ($800^{\circ}C{\sim}900^{\circ}C$), oxygen contents (21%~41%), coal feeding rate, Ca/S mole ratio (1.5~4.0), and so on. Simulation results show that the combustion furnace temperature is higher in oxy 1 than air fired. However, the temperature gradient tended to decrease with increasing oxy mixing percent. In case of $SO_x$, the higher the Ca/S mole ratio and oxy mixing percent, the higher the desulfurization efficiency.

에너지 공급 안정과 온실가스 저감이라는 목표를 달성하기 위해 저등급 석탄의 순산소 순환유동층 보일러의 적용이 새롭게 모색되고 있다. 아직까지 실증 단계의 개발이 진행되고 있기에 순산소 순환유동층 보일러에서의 저급탄 이용을 위해 주입 공기량, 조업 온도, 연료 공급량 등의 변화에 따른 연소 특성이 고찰되어야 상용 모델을 위한 설계 기준을 선정할 수 있다. 이에 본 연구에서는 공기 연소로 개발된 IEA-CFBC 모델을 순산소 연소를 전산모사하도록 개조하였고 새로운 순산소 순환유동층 모델을 이용하여 온도($800^{\circ}C{\sim}900^{\circ}C$), 산소 농도(21%~41%), 석탄 주입량, Ca/S 비율(1.5~4.0) 등의 다양한 조건에서 순산소 연소 특성을 고찰하였다. 공기 연소와 비교하여, 순산소 조건에서의 보일러 온도가 높았으나 산소 농도가 증가함에 따라 보일러의 온도구배는 감소하는 경향을 나타냈다. 더불어 Ca/S 비율, 산소농도가 높을수록 탈황 효율이 증가하는 것으로 나타났다.

Keywords

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