为了研究混合气体(O₂/N₂和O₂/N₂/CO₂)对煤自燃特性的影响，利用同步热分析仪、程序升温-气相色谱联用仪/红外光谱仪研究煤在混合气体下的特征温度、热效应/标志气体及官能团变化。结果表明：O₂/N₂气体氛围（简称气氛）下，随着N₂体积分数的增加，特征温度点滞后，TG、DTG、DSC均向高温偏移，放热量减少，燃烧阶段活化能升高，煤的最终耗氧量和CO体积分数均降低，煤中羟基增加，脂肪烃、含氧官能团、芳香烃的含量呈减少趋势；O₂/N₂/CO₂气氛下，随着CO₂体积分数的增加，特征温度点后移，放热量下降，燃烧阶段活化能减小，耗氧量、CO体积分数均降低，羟基、脂肪烃增加，含氧官能团的含量减少；当O₂体积分数相同时，O₂/N₂/CO₂混合气体中的失重率峰值、耗氧量与CO体积分数均小于O₂/N₂混合气体；−OH易被氧化发生脱水反应，煤在反应初期放热量较少，后期放热量快速增加，CO主要由−C=O生成。

In order to investigate the influence of gas mixture (O₂/N₂ and O₂/N₂/CO₂) on the spontaneous combustion characteristics of coal, synchronous thermal analyzers, temperature programmed gas chromatography/infrared spectrometers were used to study the characteristic temperature, thermal effect/indicator gas, and functional group changes of coal under gas mixture. The results show that under O₂/N₂ atmosphere, with the increase of N₂ volume fraction, the characteristic temperature point lags behind, TG, DTG, DSC all shift towards high temperature, heat release decreases, activation energy during combustion stage increases, final oxygen consumption and CO volume fraction of coal decrease, hydroxyl groups in coal increase, and the content of aliphatic hydrocarbons, oxygen-containing functional groups, and aromatic hydrocarbons shows a decreasing trend; under O₂/N₂/CO₂ atmosphere, as CO₂ increases, the characteristic temperature point shifts backward, the heat release decreases, the activation energy during the combustion stage decreases, the oxygen consumption and CO volume fraction both decrease, hydroxyl and fatty hydrocarbons increase, and the content of oxygen-containing functional groups decreases; when the volume fraction of O₂ is the same, the peak weight loss rate, oxygen consumption, and CO volume fraction in the O₂/N₂/CO₂ mixture are all lower than those in O₂/N₂; −OH is easily oxidized and undergoes dehydration reaction. Coal releases less heat in the initial stage of the reaction, but rapidly increases in the later stage. CO is mainly generated by −C=O.