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Steam Gasification Kinetics of Sawdust Char at High Temperature

톱밥 촤의 고온 수증기 가스화 특성

  • Received : 2014.07.08
  • Accepted : 2014.09.04
  • Published : 2014.12.01

Abstract

Steam gasification of sawdust char was performed in a thermobalance reactor at high temperature. Gasification temperature was changed from $850^{\circ}C$ to $1400^{\circ}C$ and steam partial pressure was 0.3, 0.5 and 0.7 atm. Three models of gas-solid reaction were applied to the reaction kinetics analysis and modified volumetric model was an appropriate model. Reaction control regime and diffusion control regime were distinct depending on the temperature. Apparent activation energy and pre-exponential factors for both of the regimes were evaluated and the effects of steam partial pressure were examined. $H_2$ concentration in the produced gas was two times higher than that of CO due to the gasification accompanying by the water gas shift reaction.

바이오매스의 수증기 가스화 특성을 고온 영역에서 살펴보고자 열중량 분석기(thermobalance)에서 톱밥 촤의 수증기 가스화 연구를 수행하였다. 반응 온도를 $850^{\circ}C$에서 $1400^{\circ}C$까지 수증기 분압을 0.3, 0.5, 0.7 atm으로 변화시키며 가스화 실험이 수행되었다. 반응 kinetics 해석은 기체-고체 화학반응의 세 가지 모델이 이용되었고 이 중 modified volumetric model이 중량 변화를 가장 잘 나타내었다. 가스화 온도 $900^{\circ}C$를 기준으로 diffusion control regime과 reaction control regime의 두 단계로 가스화가 구분되었으며 이때 각각의 regime에 대하여 활성화에너지와 빈도인자를 도출하고 수증기 분압의 영향을 살펴보았다. 가스화와 동시에 수성가스화 변환반응이 진행되어 생성기체의 $H_2$ 농도가 CO에 비하여 2배 정도 높은 값을 나타내었다.

Keywords

References

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