氧化煤复燃过程自燃倾向性特征规律

煤自燃是矿井安全生产中的主要灾害之一,火区启封时的氧化煤复燃问题尤其需要重视。为揭示不同氧化程度煤复燃特性,研究分析氧化煤指标性气体产生规律,并对特征官能团进行吸光度定性分析和峰面积定量分析。结果表明氧化煤自燃倾向性判定指数为I_(ym)I_(80℃yh)I40_(℃yh)I_(120℃yh)I_(160℃yh)I_(200℃yh)(ym代表原煤,yh代表氧化煤),原煤中还原性官能团多于氧化煤,含氧官能团少于氧化煤,低温氧化析出指标性气体速率大于氧化煤,氧化煤较原煤与氧结合能力减弱,煤自燃倾向性降低,80℃氧化10 h后的煤气体析出速率较其他温度更接近原煤,还原性官能团亦接近原煤,煤自燃倾向性更高,更易复燃。基于以上研究,确立了不同氧化程度煤复燃规律。

Characteristic rule of spontaneous combustion tendency of oxidized coal at recrudescence stage

Spontaneous combustion of coal is one of the main problems in coal mine safe production.The oxidized coal recrudescence should be paid enough attention at the unsealing stage.To reveal the re ignition characteristics of coal with different oxidation levels,the research was conducted on the development of coal spontaneous combustion at each stage.The test system for spontaneous index gases was developed to analyze the occurrence and development of index gases produced by coal with different oxidation levels,and Fourier transform infrared spectroscopy was used to investigate the characteristics of functional group by the qualitative analysis of absorbance and the quantitative analysis of peak area.The results show that the determination index for coal spontaneous combustion tendency is Iym＜I80 ℃yh＜I40 ℃yh＜I120 ℃yh＜I160 ℃yh＜I200 ℃yh(ym is raw coal,yh is oxidized coal).The amount of reducing functional groups in raw coal is larger than that of oxidized coal,while the amount of oxygen containing functional groups is less than that of oxidized coal,and the velocity of producing index gas is higher than that of oxidized coal.Compared with the raw coal,the ability of the oxidized coal to combine with oxygen in the oxidation process is weakened,the coal spontaneous combustion tendency is reduced,and the recrudescence is less likely to occur.In addition,the velocity of producing index gas of coal with 10 h oxidation at 80 ℃ is closer to that of coal with 10 h oxidation at other temperatures,and the amount of reducing functional groups is also close to that of raw coal.Therefore,the coal with 10 h oxidation at 80 ℃ is more likely to be reignited.Based on the above studies,the change law of recrudescence to coal with different oxidation levels was obtained,which provides a theoretical basis for the scientific and effective prevention of coal reignition.