화학공학소재연구정보센터
HWAHAK KONGHAK, Vol.38, No.2, 259-268, April, 2000
내부 순환 유동층 반응기에서의 석탄가스화 및 모델링
Modeling and Coal Gasification in an Internally Circulating Fluidized Bed Reactor
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초록
호주 석탄올 드래프트관(0.1m ID X 0.9m high)과 생성가스분리대를 갖는 내부 순환 유동층가스화반응기(0.3m ID X 2.7m high)에서 가스화하였다. 대기압하에서 반응온도(780-900℃), 산소/석탄비(0.30-0.53), 석탄공급량(5.3-12.1kg/h), 수증기/석탄비(0.3-0.81)의 변화에 따른 생성가스의 조성, 탄소 전환율, 냉가스 효율, 가스수율, 발열량에 미치는 영향을 규명하였다. 드래프트영역에서는 저열량가스(3.3-5.9MJ/ )를 애뉼러스 영역에서는 중열량가스(8.6-13.2MJ/ )를 얻었다. 내부 순환 유동층에서 석탄가스화반응을 예측하기 위하여 수력학적 특성, 반응 kinetics, 열분해 상관식을 기초로한 모델식을 제시하였다. 프리보드 영역에서의 연소반응이 생성가스의 조성 및 발열량에 미치는 영향을 고찰하였고, 프리보드 영역에서의 연소반응이 포함된 모델식이 조업변수의 변화에 따른 반응기의 성능을 더 잘 예측함을 확인하였다.
Australian coal was gasified in an internally circulating fluidized bed (0.3m ID X 2.7m high) with a draft tube (0.1m ID X 0.9m high) and a gas separator over the draft tube at atmospheric pressure. The effects of reaction temperature (780-900℃), oxygen/coal ratio (0.30-0.53), coal feeding rate (5.3-12.1kg/h) and steam/coal ratio (0.30-0.81) on compositions of the product gas, carbon conversion, cold-gas efficiency, gas yield and calorific value of the product gas have been determined. In the present coal gasifier, low calorific value gas (3.3-5.9MJ/㎥) in the draft tube region and medium calorific value gas(8.6-13.2MJ/㎥) in the annulus region can be obtained. A predictive mathematical model is proposed based on the bed hydrodynamics, reaction kinetics and the empirical correlation of pyrolysis yields to predict gasification characteristics in the internally circulating fluidized bed gasifer with a draft tube. The model including the effect of combustion reaction in the freeboard region can explain the reaction behavior more precisely than the model excluding the effect of combustion reaction in the freeboard region in the reactor within the range of variables studied.
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