Xiaoyun Coal Mine, Jining Mining Group Co. Ltd
College of Safety and Environmental Engineering, Shandong University of Science and Technology
Zaozhuang Mining Group Co. Ltd
State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology

为了提高浸水煤自燃预警的可靠性和准确性,采用扫描电镜实验与程序升温氧化实验研究了不同含水率煤与原煤的结构变化和氧化规律。首先对比分析了浸水煤的表面结构变化,然后通过浸泡法制备了含水率为4%、11%、18%、25%、32%的煤样,利用程序升温实验分析不同含水率煤样气体产生量随温度的变化关系。结果表明:浸水后,煤样氧化产生CO和C2H4的临界温度由73℃、180℃提前到62℃、161℃,各煤样升温过程中产生气体随温度升高而升高,含水率为18%的煤样产生的CO、CO2、C2H4和C2H6体积分数最高;在CO、C2H4可作为标志气体的基础上,引入CO与CO2体积分数比值γ和C2H4与C2H6的体积分数比值ε,分别作为煤吸氧蓄热阶段和自热氧化阶段的预测指标,即:γ≤0.019时,煤样温度小于136℃,处于吸氧蓄热阶段;0.752≤ε≤0.836时,煤样温度136~226℃,处于自热氧化阶段;γ≥0.908时,煤氧化温度大于226℃,处于加速氧化阶段。最后,基于CO、C2H4、C2H6三种标志气体和γ、ε值,建立了浸水条件下采空区遗煤自燃的分级预警防控指标体系。

In order to improve the reliable and accurate of self-ignition warning for soaked coal, this paper studied the structural changes and oxidation laws of coal with different moisture contents and raw coal by using scanning electron microscopy experiments and programmed temperature oxidation experiments. Firstly, the surface structural changes of the soaked coal were compared and analyzed. Then, coal samples with moisture contents of 4%, 11%, 18%, 25%, and 32% were prepared by soaking method. Finally, the relationship between the amount of gas produced in each coal sample and temperature using a programmed heating experiment was analyzed. The results showed that the critical temperature for the oxidation of the soaked coal samples to produce CO and C2H4 increased from ℃ and ℃ to ℃ and ℃ respectively. The amount of gas produced during the heating process of each coal sample increased with the increase of temperature. The coal sample with a moisture content of 18% produced the highest concentration of CO, CO2, C2H4 and C2H6. On the basis that CO and C2H4 could be single indicator gases, CO/CO2(γ) and C2H4/C2H6(ε) were introduced as the predictive indicators for coal oxygen absorption and thermal storage stage and self-thermal oxidation stage respectively. When γ≤ 0.019, the coal sample, with a temperature less than ℃, was in the stage of oxygen absorption and heat storage temperature. When 0.752 ≤ ε≤ 0.836, the temperature of coal sample was 136~226 ℃, and it was in the stage of the self- thermal oxidation. When γ≥ 0.908, the coal sample, with an oxidation temperature of greater than ℃, could be considered to be in the accelerated oxidation stage. Finally, based on the three single indicator gases of CO, C2H4, C2H6 and γ, ε, a graded warning and prevention indexes system for the residual coal in goaf under waterlogging conditions was established.

国家自然科学基金项目(51974176);山东省杰出青年基金项目(ZR2020JQ22);山东省高等学校青年创新团队发展计划项目(2019KJHO06)