浅埋藏煤层开采过程中,由于地表裂隙导致的漏风,使其经常处于变化的氧浓度场中。针对这一实际情况,利用煤氧化动力学测定系统,对煤样在21%,18%,14%,10.5%,5%,3%氧浓度下,进行程序升温试验。测得了不同温度下指标气CO,C2 H4,C2 H6,C3 H8浓度,并分析了其随温度变化规律,测量并计算了不同氧浓度下交叉点温度以及升温速率；对氧浓度大小影响指标气产量和其随温度变化幅度原因,以及温度特征影响效果进行必要的机理分析。结果表明：不同氧浓度下指标气CO,C2 H4,C2 H6在70℃左右有明显产量变化,分别在120℃,125℃,120℃处开始大量释放,C3 H8则在温度达到125℃左右开始大量释放；120℃前,各氧浓度下煤样温度按相同规律变化,120℃后,氧浓度越大则对应的升温速率越大,温度也越高；氧浓度不同影响了煤中脂肪烃侧链氧化产生-OH的过程,继而造成指标气产量与温度变化差异。%The coal seam under shallow cover could always be in the changing oxygen concentration field due to the air leak-age through the fracture on the ground. In view of the actual situation, the programmed temperature rising experiments were carried out for the coal samples under the conditions of 21%, 18%, 14%, 10 . 5%, 5% and 3% oxygen concentration by u-sing the coal oxidation kinetics determination system. The concentrations of the index gases CO, C2 H4 , C2 H6 and C3 H8 were measured at different temperatures, and the variation laws of the concentration with temperature were analyzed, then the crossing-point temperature and temperature rising rate at different oxygen concentrations were measured and calculated. The necessary mechanism analysis was conducted on the effect of oxygen concentration on the index gases yield and the reasons of its change with temperature, and the effect on the temperature characteristics. The results showed that under different oxygen concentrations, the obvious yield change of the index gases CO, C2 H4 and C2 H6 appear at about 70℃, and they begin to re-lease with large quantities at 120 ℃, 125 ℃ and 120 ℃ respectively, while C3 H8 begins to release with large quantity at a-bout 125 ℃. Before 120 ℃, the temperatures of coal samples under different oxygen concentrations change with the same tendency, while after 120 ℃, the more the oxygen concentration, the larger the corresponding temperature rising rate, and the higher the temperature. The different oxygen concentrations influence the process of producing -OH by oxidation of ali-phatic side chains in coal, which causes the difference of index gases yield and temperature change.
展开▼
