地下煤火通常处于多气共存条件下,CO2因其理化性质对煤贫氧燃烧特性有着重要的影响。本研究在O2/N2/CO2气氛下分别对补连塔煤和余吾煤进行了同步热分析,讨论了煤的特征参数和特性指数,利用Coats-Redfern积分法分析了CO2体积分数对煤燃烧动力学的影响规律。结果表明,15%O2能够满足煤燃烧所需氧含量,CO2的较高比热容使煤体燃烧蓄热能力提升,着火和燃烧更加稳定,综合燃烧性能显著提高。在整个热分解和燃烧阶段,煤局部燃烧反应性升高,5%CO2和15%CO2分别对补连塔煤和余吾煤表面分子活化产生明显的抑制作用。

Underground coal fires are usually under the condition of multi-gas coexistence. CO2 has an important influence on oxygen-lean coal combustion characteristics due to its physical and chemical properties. In this paper, the simultaneous thermal analyses of Bulianta coal and Yuwu coal were carried out in the O2/N2/CO2 atmosphere respectively. The characteristic parameters and characteristic indexs of coal combustion were discussed. Coats-Redfern integral method was used to analyze the effect of CO2 volume fraction on the combustion kinetics of coal. The results showed that, 15% O2 could meet the oxygen content required for coal combustion, and the high specific heat of CO2 improved the heat storage capacity of coal combustion. The ignition and combustion of coal were more stable, and the comprehensive combustion performance was significantly improved. Throughout the thermal decomposition and combustion stages, the apparent activation energy required for coal oxygen-lean combustion increased, and 5% CO2 and 15% CO2 had the most obvious inhibitory effect on the surface molecular activation of Bulianta coal and Yuwu coal respectively.