基于失碳速率的煤氧化动力学模型研究

Research on oxidation kinetics model of coal based on carbon element loss rate

碳元素脱离煤体转移到气态产物中是煤低温氧化过程的一个重要特征。通过对煤自燃气体产物生成特征的研究,提出失碳速率的概念,建立了相应的氧化动力学模型,并从理论及实验两方面予以验证。该模型可较准确地描述煤在程序升温条件下从常温氧化至110℃的过程中失碳速率的变化特征。研究表明,自燃倾向性不同的煤其失碳速率有较大的差异,同一种煤在不同温度段内失碳速率也不同,其活化能和总指前因子均有较大改变;不同温度阶段煤氧化的内在作用机制存在较大差别,仅以某一温度段的特性来衡量煤氧化能力的强弱并不全面。

Transfer of carbon element from coal to its gaseous products is an important characteristic of coal oxidation. According to the research of gaseous products producing characteristic, the loss rate of carbon element is defined and oxidation kinetics model is put forward, then proved both theoretically and experimentally. As for coal oxidation heated by temperature programming from the ambient temperature to 110℃, this model can describe the loss rate of carbon element very well. It is demonstrated that loss rates of carbon element are quite different for different coals, different temperature stages of same coal, with different activity energies and pre--exponential factors. The reaction mechanism in different stages of coal oxidation is different, therefore, just using the characteristic of only one stage to evaluate the whole coal oxidation process is not comprehensive.