摘要
为掌握煤层露头火灾的发展演化规律,采用高温程序升温试验系统模拟了风化煤的高温氧化自燃过程,得到了从常温到650℃高温氧化过程中的宏观自燃特性及其表征参数,并应用指标气体的增长率分析法确定出风化煤高温氧化的特征温度点。结果表明:风化煤在高温低氧浓度条件下仍能持续发生氧化反应,并放出大量的热量,来维持其自燃;风化煤内含有的腐植酸会随着煤温的升高,逐渐发生热分解反应,从而导致氧化反应,产生的CO_2、CH_4、C_2H_4、C_2H_6浓度增加,且CH_4、C_2H_4、C_2H_6浓度随煤温的变化规律相似,由于风化煤受到化学风化作用,使这3种气体在低温阶段的浓度都比较小,之后随着温度的升高而迅速增大;此外,煤样粒径<0.9 mm时高温氧化产生的CO浓度,比其他粒径下的CO浓度总体上都大;在400~590℃,煤样粒径为7~10 mm时,高温氧化产生的CO浓度最小。
In order to master a development evolution law of a seam outcrop fire, a high temperature programming rising experiment system was applied to simulate the high temperature oxidized spontaneous combustion process of the weathered coal and the macro spontaneous combustion features and the characteristic parameters in the normal temperature to 650℃ high temperature oxidized process were ob- tained. The increased rate analysis method of the index gas was applied to set up the weathred coal characteristic temperature point of the high temperature oxidation. The results showed that under the condition of the high temperature and low oxygen concentration, the weath- ered coal still could keep the oxidized reaction occurred and could release great heat to maintain the spontaneous combustion. The humic acid contained in the weathered coal would steadily occur the thermal decomposition reaction with the coal temperature increased and would cause CO2 ,CH4 , C2H4 and C2H6 gas concentrations from the oxidation increased. Meanwhile, the CH4 , C2H4 and C2H6 gas con- centrations would be similar to the coal temperature variation law. Due to the weathered coal affected by the chemical weathered function, those three gas concentrations would be low at the low temperature stage and then could be increased with the temperature increased. In addition, the CO gas concentration occurred from the high temperature oxidation of the coal sample with a particle size less than 0.9 mm would have a high CO concentration generally than other particle size. From 400 ~ 590℃, when the particle size was 7- 10 mm, CO con- centration value from the high temperature oxidation of the coal sample would be minimum.
出处
《煤炭科学技术》
CAS
北大核心
2017年第1期73-77,105,共6页
Coal Science and Technology
基金
国家自然科学基金资助项目(51204136)
中国博士后科学基金资助项目(2016M590963)
陕西省自然科学基金资助项目(2016JM5016)
关键词
风化煤
高温氧化
气体浓度
特征温度点
粒径
weathered coal
high temperature oxidation
gas concentration
characteristic temperature point
particle size
