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水分在煤低温氧化过程中的作用具有两面性,根据其水分含量的多少促进或抑制煤的自燃。采用程序温升法研究了原煤样和50℃干燥煤样低温(≤100℃)氧化过程的耗氧量变化规律。对比分析表明,不同水分条件煤样耗氧量随温度的升高总体呈增加趋势,义马和朱仙庄原煤在初始阶段出现耗氧量减小,说明在100℃以前煤的升温特性主要受外在水分的影响;干燥后耗氧量相对原煤有显著增大,外在水分蒸发时吸收大量的热,以汽化潜热的方式带走,使煤体周围的热量不易聚集,且蒸汽压阻止了煤与空气中氧气的接触,外在水分在低温缓慢自热阶段主要起阻化作用;较低含水量与煤表面接触会释放一定量的润湿热而起到促进作用。
The role of moisture in coal low-temperature oxidation process has two sides, according to its moisture content to promote or inhibit the spontaneous combustion of coal. The process of temperature rise was used to study the changes of oxygen consumption of the raw coal samples and the dry coal samples at 50 ℃ at low temperature (≤100 ℃). The comparative analysis shows that the oxygen consumption of coal samples with different water conditions increases with the increase of temperature, and the oxygen consumption of Yima and Zhu Xianzhuang coal decreases in the initial stage, which shows that the temperature rise characteristics of coal are mainly affected External moisture influence; after drying, oxygen consumption increased significantly compared with coal, external water evaporation absorbs a large amount of heat to latent heat of vaporization away, so that the heat around the coal body is not easy to gather, and the vapor pressure to stop Coal and oxygen in the air contact, the external moisture in the low temperature slow self-heating phase mainly played a deterrent effect; lower water content and the coal surface will release a certain amount of moist heat and play a catalytic role.