Evaluation on Reaction Kinetics of Cow Manure in Carbonization Process

탄화공정에서의 우분 반응속도 평가

Through the study of the basic characteristics of cow manure and the characteristics of carbonization residue, carbonization degree, conversion rate, kinetic reactions, and activation energy for cow manure were examined. Since the heating value of cow manure was very low, it was converted to carbonization residue as a fuel with heating value of 4,300 kcal/kg by carbonization processes. Conversion rate was increased rapidly up to 10 minutes of the initial reaction stage and was increased with increasing temperature. The carbonization of cow manure could be described by the 1st order reaction. Frequency factor(A) of reaction rate for cow manure was evaluated to be $1.34{\times}10^{-2}min^{-1}$, the activation energy was estimated to be 5,196.4 cal/mol. As carbonization temperature increased from $250^{\circ}C$ to $400^{\circ}C$, the kinetic reaction was increased from $0.2107min^{-1}$ to $0.0679min^{-1}$. From the result of the carbonization for cow manure, it can be determined that the optimal conditions of the carbonization process were 20 minutes in carbonization time and $350^{\circ}C$ for carbonization temperature.

우분의 기본 특성과 우분 탄화물의 특성에 대한 검토를 통해 탄화도, 전환율, 반응속도 및 활성화 에너지에 대하여 고찰하였다. 우분 시료 자체의 저위발열량은 272 kcal/kg로 낮게 나타나 연료로써의 개질이 필요하므로 탄화공정을 이용하여 탄화물의 발열량을 4,300 kcal/kg 이상인 연료로 전환 하였다. 전환율은 반응초기인 10분까지 급격히 증가하였으며, 온도가 증가함에 따라 높게 나타났다. 우분 탄화공정에서의 반응속도는 1차식으로 나타내었으며, 빈도인자(A)는 $1.34{\times}10^{-2}min^{-1}$, 활성화 에너지는 5,196.4 cal/mol로 평가되었다. 반응속도 상수는 $250^{\circ}C$일 때 $0.0679min^{-1}$, $400^{\circ}C$일 때 $0.2107min^{-1}$로 온도가 증가함에 따라 반응속도도 증가하는 것으로 나타났다. 우분 탄화에서의 반응속도에 대한 평가한 결과, 탄화공정의 최적조건은 탄화온도 $350^{\circ}C$, 탄화시간 20분으로 나타났다.