煤粉是煤炭利用过程中常用的一种形式，其粒度小，表面积大，氧化活性强。生产过程中为了提高煤粉利用效率主要采用高温干燥、活化等工艺进行加工，由于环境温度高，煤粉的自燃氧化性显著增强，易发生自燃。在生产、输运及使用过程中煤粉自燃事故时有发生，甚至引起粉尘爆炸事故，严重威胁企业安全生产。煤粉自燃主要发生在空气或低氧气浓度情况下，同时降低氧气浓度也是防治煤粉自燃的手段之一。因此，本文开展了不同氧气浓度时煤粉氧化燃烧过程中热效应、动力学特征、煤粉自燃演化过程及气体变化规律的研究。研究成果对煤粉自燃演化过程的理解和自燃事故的防治有重要指导意义。 采用差示扫描量热（DSC）和C80微量热实验系统研究得到了同氧气浓度时煤粉氧化燃烧全过程的热释放特性。根据煤粉氧化燃烧过程中DSC曲线变化规律，提出了一种煤粉燃点温度判定方法；确定了煤粉的初始放热温度、燃点温度和燃尽温度等特征温度。随氧气浓度的降低，煤粉氧化放热强度和放热量均逐渐降低，特征温度逐渐升高。采用数据拟合得到煤粉低温氧化过程中放热量符合Rational 2D三维数学模型。计算了不同氧气浓度时煤粉氧化放热量与氧气浓度为21%时的比值，得到了低氧气浓度对煤粉低温氧化放热过程的抑制效果具有显著的阶段特性。 采用热重红外联用实验系统研究得到了煤粉在氧化燃烧过程中质量、氧化燃烧阶段特性及气态产物的变化规律。低氧气浓度时煤粉氧化热反应过程整体呈现出滞后，氧浓度降低对热解氧化和燃烧失重阶段影响显著；煤粉氧化过程中反应速率和最大反应速率均随氧气浓度降低而降低。在吸氧增重阶段煤粉的表观活化能随转化率（温度）升高而逐渐升高，在热解燃烧阶段煤粉的表观活化能随转化率（温度）升高为先增大后减小的变化趋势。氧气浓度降低会抑制煤粉中活性结构燃烧，特别是活化能较高结构，造成低氧气浓度下煤粉表观活化能降低。煤粉氧化燃烧过程中CO2产生量远大于CO产生量。随氧气浓度降低，CO2和CO气体峰值出现温度和结束温度逐渐增高，而产生量明显降低。 构建了高温环境中煤粉自燃氧化实验测试系统，研究了高温环境中煤粉自燃过程中温度和气体变化规律。得到煤粉自燃演化过程可分为被动升温、氧化升温、快速氧化和燃烧阶段，随氧气浓度降低煤粉临界自燃温度和着火延迟时间显著的增大。构建了煤粉自燃过程中的传热模型，采用Frank-Kamenetskii理论计算得到了不同氧气浓度时临界参数，煤粉临界自燃尺寸随临界自燃温度的升高而逐渐降低，煤粉自燃危险性增大。随煤粉反应温度升高，耗氧速率、CO产生量和C2H4气体产生量逐渐升高。不同氧气浓度情况下CO/CO2比值在一定温度时发生交叉，在交叉点温度之后煤粉的CO/CO2比值随氧气浓度的降低而降低。

Pulverized coal is one type of coal that commonly used during utilization, which has small particle size, great surface area, and high oxidation activity. To improve the utilization efficiency of pulverized coal during production, drying and activation are conducted under high temperature. These treatments cause that the spontaneous combustion of pulverized coal is significantly enhanced. The spontaneous combustion is prone to happen during production, transportation and utilize, and even causes the explosion of pulverized, which seriously threatens the safe production of enterprises. Spontaneous combustion of pulverized coal mainly occurs in air or low oxygen concentration environment, and reducing oxygen concentration is also one of the means to prevent spontaneous combustion of pulverized coal. Under various oxygen concentrations, this paper investigated the thermal effects, kinetic characteristics, evolution of spontaneous combustion, and gases emission of pulverized coal with different degrees of metamorphism. The results have great significance for better understanding and help to prevent and control the spontaneous combustion of pulverized coal. The differential scanning calorimetry and the C80 microthermal experimental systems were adopted to test the exothermic characteristics of pulverized coal during oxidative combustion in different oxygen concentrations. A method determining the ignition temperature of pulverized coal was proposed. Characteristic temperatures, such as initial temperature of heat release, ignition temperature, and burnout temperature, were determined. With the decrease in oxygen concentration, the intensity and quantity of heat release gradually decreases, while the characteristic temperature gradually increases. Based on data fitting, the heat release of pulverized coal during the low-temperature oxidation conforms to Rational 2D three-dimensional mathematical model. Moreover, the ratios of quantity of heat release under lower oxygen concentration to that of under 21% oxygen concentration were calculated, which indicates that reducing oxygen concentration has significant stage characteristics when inhibiting the thermal of pulverized coal at low temperature oxidation stage. The variations in mass and gaseous products were investigated by thermogravimetry infrared spectrum coupling technology (TG-FTIR). Also, stage characteristics of oxidative combustion of pulverized coal were analyzed. The thermal reaction of pulverized coal oxidation in lower oxygen atmosphere lags behind that in air atmosphere, and the decrease in oxygen concentration has an obvious influence on the thermal decomposition and combustion stages. In addition, the maximum and average of reaction rates decrease with decreasing oxygen concentration. The apparent activation energy of pulverized coal gradually increased with the increased of conversion rate (temperature) during the oxygen-absorption mass-gain stage whereas it first increases and then decreases in the process of decomposition and combustion stage. As the oxygen concentration decreases, the active structures, especially these with high activity, are inhibited, resulting in a decrease in the apparent activation energy. The production of CO2 was much greater than that of CO during oxidation combustion of pulverized coal. With the decrease in oxygen concentration, the temperature corresponding to the CO2 and CO peaks is significantly reduced, while the end temperature gradually increases. Moreover, the amount is significantly reduced. The experimental testing system for the spontaneous combustion of pulverized coal at high temperature was established, by which the measurement of temperature and gas emission was realized. The spontaneous combustion process of pulverized coal was divided into passive heating, oxidation heating, rapid oxidation, and combustion stages. The critical spontaneous combustion temperature and ignition delay time decreases significantly with the oxygen concentration going down. The model for the heat transfer during spontaneous combustion of pulverized coal was established. Based on the Frank-Kamenetskii theory, the critical size causing the spontaneous combustion of pulverized coal decreases with the increase in critical spontaneous combustion temperature, and the risk of spontaneous combustion of pulverized coal increased. As the temperature rises, the rate of oxygen consumption, the amounts of CO and C2H4 gradually increases. The CO/CO2 ratio under various oxygen concentrations crosses with each other at a certain temperature, after which the CO/CO2 ratio decreases when the oxygen concentration decreases.