During the coal mining process, fractures generated can lead to crude oil infiltrating into coal seams, forming coal–oil symbiosis (COS). The complex three-phase interaction of coal–oil–oxygen makes the mechanism of COS spontaneous combustion filled with uncertainties. This study utilized synchronous thermal analysis to analyze the physico-chemical behavior of raw coal and COS at different heating rates. Additionally, detailed characterization of their surface morphology and functional groups was conducted using scanning electron microscopy (SEM) and in situ FTIR technology. The findings suggest that the coverage of crude oil on the surface of coal inhibits the adsorption of oxygen by the coal, leading to the disappearance of the stage where COS absorbs oxygen and gains weight. Moreover, the continuous decline of –OH groups and aliphatic hydrocarbons in the later stages suggests that crude oil acts as a catalyst for combustion during the latter stages of the reaction. The Kissinger–Akahira–Sunose, Starink, and Flynn–Wall–Ozawa methods showed that the apparent activation energy of COS is 23.3 and 19.7% lower than that of raw coal in thermal decomposition and combustion stages, respectively.

在煤炭开采过程中，产生的裂缝会导致原油渗入煤层，形成煤油共生（COS）。煤-油-氧复杂的三相相互作用使得COS自燃机理充满不确定性。本研究利用同步热分析来分析原煤和 COS 在不同加热速率下的物理化学行为。此外，还使用扫描电子显微镜 (SEM) 和原位 FTIR 技术对其表面形态和官能团进行了详细表征。研究结果表明，原油在煤表面的覆盖抑制了煤对氧的吸附，导致COS吸氧增重阶段消失。此外，后期-OH基团和脂肪烃的持续下降表明原油在反应后期充当了燃烧催化剂。 Kissinger-Akahira-Sunose、Starink 和 Flynn-Wall-Ozawa 方法表明，COS 在热分解和燃烧阶段的表观活化能分别比原煤低 23.3% 和 19.7%。