Coal char gasification with steam and H2:
II Modified random pore model
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摘要:
采用热天平对神府煤1200℃快速热解焦进行常压水蒸气/惰性气气化及水蒸气/氢气气化。考察神府煤焦在875℃~950℃时与水蒸气/惰性气的气化反应和水蒸气/氢气的气化反应特性,两者的特征曲线明显不同。不加氢的水蒸气气化反应速率随碳转化率的增加缓慢而均匀地下降;加氢水蒸气气化反应速率随碳转化率的增加先迅速降低，而后降低较缓慢。此种形式的气化曲线以往的动力学模型很难进行模拟，研究根据随机孔模型提出了一个新的气化动力学模型。此模型拟合的数据与实验数据比较，证明了修正的随机孔模型可以更好的模拟煤焦的加氢水蒸气气化，相关系数达到0.996以上。用修正模型求得的神府煤焦加氢水蒸气气化的活化能为251.990kJ/mol，指前因子为5.97877×109min-1。
Abstract:The characteristics of gasification reaction with steam or H2O/H2 mixed gases for Shenfu coal char pyrolyzed at 1200℃ was studied at 875℃~950℃ and ambient pressure by TGA. The curves of gasification rate and carbon conversion of coal char gasification with steam and H2O/H2 mixed gases are quite different. The gasification rates with steam decrease steadily. However, the gasification rates with H2O/H2 mixed gases decreases rapidly at lower carbon conversion and then slowly at higher carbon conversion, which is fitted difficultly by the existed models. A new gasification kinetics model was proposed based on the random pore model. Comparing the experimental data and the curve fitted by the new models, it can be seen that the experimental data of coal char gasification with H2O/H2 mixed gases can be fitted perfectly and the correlation coefficients are all above 0.996. The kinetics parameters of coal char gasification with H2O/H2 mixed gases for the new model are: Ea(activity energy)=251.990kJ/mol，k0(pre-exponential factor)=5.97877×109min-1.
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Key words:
- coal char /
- gasification /
- steam /
- hydrogen /
- modified random pore model
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