风速影响下煤矸石山自燃危险区分布规律研究
Study on the distribution law of spontaneous combustion danger zone of coal gangue pile under the influence of wind speed
王文才 1杨少晨 1王鹏 1吴周康 1李扬康 1高小雷2
作者信息
- 1. 内蒙古科技大学矿业与煤炭学院,内蒙古包头 014010
- 2. 鄂尔多斯市智慧能源科技有限公司,内蒙古鄂尔多斯 017000
- 折叠
摘要
外界环境风速对煤矸石山自燃危险区分布有明显影响.为研究其变化规律,首先从渗流场、氧气场及温度场的角度进行理论分析,明确自燃机理.然后对煤矸石样品进行热重分析,通过热重-微商热重(Thermogravimetry and Differential Thermogravimetry,TG-DTG)与 示 差扫描量热(Differential Scanning Calorimetry,DSC)-转化率曲线得出煤矸石自燃过程中关键温度点,将关键温度点作为自燃危险区划分的判别条件.最后通过FLUENT模拟对不同环境风速下煤矸石山三场变化规律进行研究,计算自燃危险区面积并进行拟合,对煤矸石山现场进行治理效果验证.结果表明:在θ2温度点后,煤矸石山出现局部缓慢燃烧现象,转化率也进入急速增加阶段,因此将θ2温度点(332.42℃)作为自燃危险区划分的判别条件;煤矸石山自燃危险区面积随风速增加呈先增加后减小的趋势,当风速为1.65 m/s时,其面积达到最大值75.25m2;当煤矸石山坡面覆土厚度为0.5 m、覆土时间为30 d时,其自燃危险区温度下降范围在202～232 ℃,治理效果良好.
Abstract
The distribution of spontaneous combustion risk areas in the coal gangue pile is significantly influenced by external environmental wind speed.To investigate the influence of wind speed,this research begins with a theoretical analysis from the perspectives of permeation fields,oxygen concentration fields,and temperature fields to elucidate the mechanism of spontaneous combustion.Subsequently,thermal gravimetric analysis is conducted on coal gangue samples to determine crucial temperature thresholds during the self-ignition process,which serve as demarcation criteria for spontaneous combustion risk areas.Finally,simulations are performed using FLUENT software to explore changing patterns within the tripartite fields of coal gangue piles under different environmental wind speeds.This method enables the calculation of dimensions for spontaneous combustion risk areas that are subsequently subjected to curve fitting.Moreover,on-site measures for management and efficacy validation are undertaken.The research findings reveal that within coal gangue piles,there are localized gradual combustion phenomena accompanied by a rapid increase in conversion rates when the post-θ2 temperature reaches the threshold of 332.42 ℃.Therefore,it is necessary to adopt θ2 temperature thresholds as criteria for identifying areas at risk of spontaneous combustion.Additionally,the dimensions of these risk areas in coal gangue piles show an initial enlargement followed by a gradual reduction with increasing wind speed.At a wind speed of 1.65 m/s,the area reaches its maximum extent at 75.25 m2.When the slope surface of the coal gangue pile is covered with a layer of topsoil that is 0.5 m thick for 30 days,the temperature within the risk area drops to a range between 202 ℃ and 232 ℃,indicating effective management measures have been implemented.These research outcomes are highly significant for preventing and managing spontaneous combustion in coal gangue piles in China.
关键词
安全工程/煤矸石山/自燃危险区/热重分析/数值模拟Key words
safety engineering/coal gangue pile/spontaneous combustion hazardous area/thermogravimetric analysis/numerical simulation引用本文复制引用
基金项目
国家自然科学基金项目(52064043)
内蒙古煤炭绿色开采与绿色利用协同创新中心平台建设项目(2023CXPT003)
出版年
2024
NETL
NSTL
万方数据