煤炭地下气化反应动力学特性的研究

煤炭地下气化过程中，高温的碳与二氧化碳和水蒸气发生的非均相反应决定了出口煤气的组分和热值。鉴于此，在煤焦与CO2和H2O（g)反应活性实验的基础上，研究了唐山刘庄煤焦与CO2和H2O（g)气化反应的动力学特性，确定了其化反应的速率表达式，得出其反应活化能分别为140．41kJ/mol和171．53kJ/mol。实验结果表明，还原带温度在1000℃-1100℃时，CO2具有较高的还原主;温度达1000℃时，H2O（g)分解可视为不可逆反应，且生成CO的反应速率明显大于生成CO2的反应速率，出口煤气组成中CO的浓度为CO2的7倍多，在上述工作的基础上，建立了“收缩反应核”模型，并分析了多相化学反应速度与温度的关系。

STUDY ON THE REACTION KINETIC CHARACTER IN UNDERGROUND COAL GASIFICATION

The kinetic character of CO2 reduction and H2O(g) decomposition in Liuzhuang underground coal gasification at Tangshan is studied on the basis of the experiment for reaction activity of coal coke and CO2 and H2O(g). The test apparatus, method and test procedure are introduced, and kinetic parameters of the gasification reaction for CO2 and H2O(g) have been calculated, the expressions for reaction rate is determined, and the activation energy obtained is 140.41?kJ/mol and 171.53?kJ/mol, respectively. Based on the diffusion-kinetics theories, “contraction reaction nucleus” model is established, and the relation between polyphase chemical reaction rate and temperature is analysed. The results indicate that there is a higher reduction rate for CO2 when the temperature range of reduction zone is 1?000?℃～1?100?℃ and decomposition reaction of H2O(g) is regarded as irreversible one when the temperature reaches 1?000?℃. The reaction rate of CO generation is obviously higher than that of CO2 formation. The concentration of CO in gas compositions at vent is more than seven times higher than that of CO2. The calculation value by the model can be well identical with the experiment result, which proves the correctness and rationality of the “contraction reaction nucleus” model.