基于不同含水率气煤的低温氧化实验研究

Experimental study on low temperature oxidation of gas coal with different water content

为了研究不同含水率气煤的自燃特性,通过程序升温实验系统,分别对5种煤样进行低温氧化实验。实验结果表明:在低温氧化过程中,不同含水率气煤的自燃特性参数均随温度的升高呈指数变化趋势;煤样的CO与CO_(2)体积分数、耗氧速率、放热强度均表现出低含水率下大于原煤,高含水率下小于原煤的规律;在加速氧化阶段,原煤的活化能为75.7 kJ/mol,相比之下含水率为5.87%、9.81%、13.81%的煤样活化能分别降低了6.8、25.6、4.6 kJ/mol,而含水率17.85%煤样的活化能却上升了4.1 kJ/mol。研究结果表明:一定范围内水分含量越大,煤样的表观活化能越小,煤的自燃倾向性越高;而过量水分会抑制热量积聚,使煤的活化能变大,自燃倾向性变低。

In order to study the spontaneous combustion characteristics of gas coal with different water content,low-temperature oxidation experiments were carried out on five kinds of coal samples respectively through the programmed temperature experiment system.The test results show that in the process of low temperature oxidation,the spontaneous combustion characteristics of gas coal with different water content change exponentially with the increase of temperature.The volume fraction of CO and CO_(2),oxygen consumption rate and exothermic intensity of coal samples are higher than raw coal at low water content and lower than raw coal at high water content.In the accelerated oxidation stage,the activation energy of raw coal is 75.7 kJ/mol,while the activation energy of coal sample with water content of 5.87%,9.81%and 13.81%is decreased by 6.8 kJ/mol,25.6 kJ/mol and 4.6 kJ/mol,respectively.Meanwhile,the activation energy of coal sample with water content of 17.85%is increased by 4.1 kJ/mol.The results show that within a certain range,the higher the moisture content,the lower the apparent activation energy and the higher the spontaneous combustion tendency of coal.However,excessive moisture will inhibit the accumulation of heat,and the activation energy of coal will increase and the spontaneous combustion tendency will decrease.