Abstract Coal spontaneous combustion in the goaf usually occurs in the multi-component gases environment. In this work, the multi-component gases competitive adsorption properties and its effects on the coal oxidations were investigated by gas adsorption analyzer and in-situ FTIR. Results show that the order of gases adsorption selectivity on coal surface based on IAST is that: CO2 > CH4 > O2 > N2. For all the selected gas components, interactions between the gases and the coal surface undergo two main mechanisms: the physical competitive adsorption or desorption under lower temperature condition and the chemical adsorption or reaction under higher temperature conditions. In ambient temperature conditions, coal spontaneous combustion would be hindered due to the stronger adsorption capability of CH4 and CO2 on coal surfaces. At the late oxidation stage, irreversible chemical adsorption of O2 would be gradually strengthened replaces and O2 preferentially reacts with –CH3/–CH2– to generate much more oxygen-containing functional groups. Reactions of CH4 with O2 on the high-temperature coal surface would accelerate the coal spontaneous combustion, which increases the risk of coal spontaneous combustion.

中文翻译：

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采空区多组分气体竞争吸附对煤自燃特性的影响

摘要 采空区煤自燃通常发生在多组分气体环境中。在这项工作中，通过气体吸附分析仪和原位 FTIR 研究了多组分气体竞争吸附特性及其对煤氧化的影响。结果表明，基于IAST的煤表面气体吸附选择性顺序为：CO2>CH4>O2>N2。对于所有选定的气体组分，气体与煤表面之间的相互作用主要有两种机制：较低温度条件下的物理竞争吸附或解吸和较高温度条件下的化学吸附或反应。在常温条件下，煤表面对 CH4 和 CO2 的吸附能力较强，会阻碍煤的自燃。在氧化后期，O2 的不可逆化学吸附将逐渐加强，O2 优先与–CH3/–CH2– 反应生成更多的含氧官能团。CH4 与O2 在高温煤表面发生反应会加速煤自燃，增加煤自燃的风险。