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为分析煤自燃早期气体指标变化特征规律,更好地解决煤矿现场灭火救灾决策问题,通过煤自燃程序升温试验,首先得到煤样气氛中O2,CO,CO2,CH4,C2H4和C2H6气体的体积分数随温度的变化规律。根据煤体温度,将煤自燃前期划分为5个阶段(潜伏、储热、蒸发、活跃和乏氧)。分析3种不同变质程度的煤样的气体指标在各阶段的变化特征。建立煤自燃气体指标与特征温度阶段区间的对应关系。结果表明:在自燃潜伏阶段,煤的变质程度越低,早期越易产生CO,越难产生CH4;在储热阶段,煤的变质程度越低,早期越易且越快产生C2H6;在蒸发阶段,煤内外在水分脱附,低变质煤的C2H4也随之产生;在活跃阶段,各种气体体积分数均有剧烈增高的趋势,较高变质煤的C2H4也随之产生;在乏氧阶段,O2体积分数低于15%,与O2体积分数相关指标(CO/ΔO2,CO/CO2等)趋势有所改变。
In order to analyze the characteristics and rules of early gas index changes during coal spontaneous combustion and to better solve the problem of fire fighting and disaster relief in coal mine, the volume fraction of O2, CO, CO2, CH4, C2H4 and C2H6 gas in coal sample atmosphere With the temperature changes. According to the temperature of the coal body, the spontaneous combustion of coal is divided into five stages (latent heat storage, evaporation, active and hypoxia). The gas characteristics of three coal samples with different metamorphic degrees were analyzed in different stages. Establishing Corresponding Relationships between Indexes of Spontaneous Combustion Gas and Stages of Characteristic Temperature. The results show that the lower the degree of coal metamorphism is, the easier it will be to produce CO in the early stage of spontaneous combustion and the harder to produce CH4. In the heat storage stage, the lower the degree of coal metamorphism is, the earlier the easier and faster the production of C2H6. During the evaporation stage , Both inside and outside of the coal desorption of water, low metamorphic coal C2H4 also will be generated; in the active phase, the various gas volume fraction has a dramatic increase in the trend of higher metamorphic coal C2H4 also will be generated; in the hypoxia stage, O2 volume fraction below 15%, and O2 volume fraction related indicators ( CO / ΔO2, CO / CO2, etc.) trends have changed.