8.8 m超大采高工作面煤自燃防治经验探讨

Discussion on prevention and control experience of coal spontaneous combustion in 8.8 m super large mining height working face

  • 摘要: 超大采高工作面煤自燃监测数据包括气体浓度、温度等,研究方法包括实验、数值模拟、现场观测等。现有研究大多未考虑各指标之间的关系,研究手段及数据分析方法单一。针对该问题,以上湾煤矿采高为8.8 m的12401工作面为例,通过煤自燃实验、现场“三带”实测及数值模拟相结合的方式,分析煤自燃火灾过程中气体浓度与温度之间的关联关系,总结采空区内因火灾发火规律和特征。建立地面钻孔注氮模型,反演了采取注氮措施前后O2浓度场、CO浓度场、温度场和“三带”分布变化规律;针对高温异常区域,根据数值模拟结果选取注氮位置,采用地面与井下一起注氮的方式降低火灾危险性。研究结果表明:CO可作为预测煤自燃的指标气体,CO2和CH4不能作为指标气体,C2H6,C2H4,C2H2,H2可作为辅助指标气体;采取注氮措施后,氧化升温带的宽度大大减小,CO体积分数明显降低,最高点温度迅速下降,惰化效果显著;高温异常区域CO体积分数及温度有逐渐下降的趋势,验证了注氮位置的合理性和注氮措施的有效性。

     

    Abstract: The monitoring data of coal spontaneous combustion in super large mining height working face includes gas concentration, temperature, etc. The research methods include experiments, numerical simulations, on site measurements, etc. Most of the existing studies have not considered the relationship between the indicators, and the research methods and data analysis methods are single. In order to solve this problem, taking the working face with a mining height of 8.8 m in Shangwan Coal Mine as an example, this paper analyzes the correlation between gas concentration and temperature in the process of coal spontaneous combustion and summarizes the law and characteristics of fire in the goaf area through a combination method of coal spontaneous combustion experiment, on-site "three zone" measurement and numerical simulation. A surface borehole nitrogen injection model is established, and the changes of O2 concentration field, CO concentration field, temperature field and "three zone" distribution before and after the nitrogen injection measures are inverted. For the high temperature abnormal area, the nitrogen injection location is selected according to the numerical simulation results. And the combined method of surface nitrogen injection and mine nitrogen injection is adopted to reduce the fire hazard. The research results show that CO can be used as an indicator gas for predicting coal spontaneous combustion, O2 and CH4 cannot be used as indicator gases, and C2H6, C2H4, C2H2 and H2 can be used as auxiliary indicator gases. After the nitrogen injection measures are taken, the width of the oxidation heating zone is greatly reduced, and the CO volume fraction is significantly reduced. The highest temperature drops rapidly and the inerting effect is significant. The CO volume fraction and temperature in the high temperature abnormal area show a gradual decrease trend, which verifies the rationality of the nitrogen injection location and the effectiveness of nitrogen injection measures.

     

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