煤自燃温度分布预测模型试验研究与优化

Experimental study and optimization of a coal spontaneous combustion temperature distribution prediction model

  • 摘要: 随着煤自燃预测场景复杂化与数据量的增加,现有基于神经网络模型预测的煤自燃温度方法难以精准捕捉特定场景下的关键致灾前兆,导致其预测精度与可靠性在实际应用中显著下降,难以满足煤矿智能化发展下煤自燃预测的需求。针对上述问题,通过研究通风影响下的煤自燃多特征指标数据变化规律,提出了一种基于粒子群(PSO)优化BP神经网络的煤自燃高温点预测模型(PSO−BP),选择O2,CO,CO2,CH4浓度和距离进风口的高度5个因素作为模型输入参数,将温度值作为模型预测数据。实验结果表明:随着煤温的升高,煤样的氧化速度加快,煤的自然发火过程呈现出三阶段变化特点,O2浓度呈现阶段性下降趋势,CO,CO2和CH4浓度随供风时间均呈指数变化,高温区域呈现出沿逆风流方向向进风侧动态迁移的规律;通过参数寻优后,PSO−BP的平均绝对误差(MAE)相较于优化前下降了1.2%,平均偏差误差(MBE)下降了58.5%,均方根误差(RMSE)下降了18.6%。选取甘肃靖煤能源有限公司宝积山矿区某矿东1煤层进风侧与回风侧采空区数据进一步验证该模型,结果表明,PSO−BP在不同煤层的误差指标均为最小,且其在不同煤层的误差指标波动范围均小于BP神经网络模型误差波动范围。

     

    Abstract: With the increasing complexity of coal spontaneous combustion prediction scenarios and the growth of data volume, existing coal spontaneous combustion temperature prediction methods based on neural network models are unable to accurately capture key disaster-inducing precursors under specific scenarios, resulting in a significant decline in prediction accuracy and reliability in practical applications, which fails to meet the requirements of coal spontaneous combustion prediction under the development of intelligent coal mines. To address these issues, by investigating the variation patterns of multiple characteristic indicators of coal spontaneous combustion under ventilation influence, a high-temperature point prediction model for coal spontaneous combustion based on a Particle Swarm Optimization (PSO)-optimized BP neural network (PSO-BP) was proposed. Five factors, including the concentrations of O2, CO, CO2, CH4, and the height from the air inlet, were selected as the input parameters of the model, and temperature values were taken as the prediction output. Experimental results showed that as coal temperature increased, the oxidation rate of coal samples accelerated, and the spontaneous combustion process of coal exhibited a three-stage evolution characteristic. The O2 concentration showed a stage-wise decreasing trend, while the concentrations of CO, CO2, and CH4 exhibited exponential variations with ventilation time. The high-temperature zone dynamically migrated toward the air inlet side along the direction opposite to the airflow. After parameter optimization, the Mean Absolute Error (MAE) of the PSO-BP model was reduced by 1.2% compared with that before optimization, the Mean Bias Error (MBE) was reduced by 58.5%, and the Root Mean Square Error (RMSE) was reduced by 18.6%. Data from the goaf on the intake and return air sides of the No. 1 East coal seam in a mine of the Baojishan mining area of Gansu Jingmei Energy Company Ltd. were further selected to validate the model. The results showed that the PSO-BP model achieved the minimum error indices across different coal seams, and the fluctuation ranges of its error indices were smaller than those of the BP neural network model across different coal seams.

     

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