Nitrogen is widely used to prevent the spontaneous combustion of coal in underground coal mines. A spontaneous combustion-prone coal seam was studied to investigate the restraining effect of nitrogen on coal oxidation in different oxidation stages, based on non-isothermal thermogravimetry-differential scanning calorimetry (TG-DSC) and electron paramagnetic resonance (EPR) experiments. We found that the key feature temperatures grow steadily with increasing nitrogen in the oxidation environment, resulting in longer oxidation stages. The most significant finding is that there is a stagnation of the inhibitory effect of nitrogen on coal oxidation in the range of 85.0–95.0% nitrogen in the slow and the rapid oxidation stages, owing to the competitive adsorption of coal by nitrogen and oxygen. However, the restraining effect cannot be reflected by the kinetic parameters of the coal before it reaches the thermal decomposition and combustion stage. Nitrogen can also affect free radical types and free radical concentrations during coal oxidation: the higher the concentration of nitrogen in the oxidation environment, the greater the number of free radical types and the lower the free radical concentration. This experimental study improves the understanding of the restraining effect of nitrogen on coal oxidation in different oxidation stages and provides an important reference for coal fire prevention in spontaneous combustion-prone coal seams.

氮被广泛用于防止地下煤矿中煤炭的自燃。基于非等温热重-差示扫描量热法（TG-DSC）和电子顺磁共振（EPR）实验，研究了自燃倾向煤层，研究了氮在不同氧化阶段对煤氧化的抑制作用。我们发现关键特征温度随着氧化环境中氮含量的增加而稳定增长，从而导致更长的氧化阶段。最重要的发现是，在缓慢和快速氧化阶段，由于氮和氧的竞争性吸附，氮对煤氧化的抑制作用停滞在85.0-95.0％的范围内。然而，煤达到热分解燃烧阶段之前的动力学参数不能反映其抑制作用。氮还可以影响煤氧化过程中的自由基类型和自由基浓度：氧化环境中氮的浓度越高，自由基类型的数量越多，自由基浓度越低。这项实验研究增进了人们对氮在不同氧化阶段对煤氧化抑制作用的理解，为预防易自燃煤层的煤着火提供了重要参考。氧化环境中氮的浓度越高，自由基类型的数量越多，并且自由基浓度越低。该实验研究增进了人们对氮在不同氧化阶段对煤氧化的抑制作用的认识，为预防易自燃煤层的煤着火提供了重要参考。氧化环境中氮的浓度越高，自由基类型的数量越多，并且自由基浓度越低。该实验研究增进了人们对氮在不同氧化阶段对煤氧化的抑制作用的认识，为预防易自燃煤层的煤着火提供了重要参考。