ABSTRACT

In order to study the influence of water addition in the low-temperature pre-pyrolysis process on the coal spontaneous combustibility, programmed heating experiments were carried out to test secondary oxidation characteristics of coal which was pretreated by isothermal pyrolysis at 80°C with different water content of 5.96%, 10.11%, 13.92%, and 17.48%. The results showed that the concentration of CO and CO₂ decreased, and tended to be constant along with time during the pre-pyrolysis process in which moisture had a positive effect on CO₂ release. The thermostatic pre-heating at 80°C inhibited the spontaneous combustion of coal, while the presence of water during the pre-pyrolysis process showed the competitive characteristics of promoting and inhibiting the coal spontaneous combustion at the same time. From the perspective of CO and CO₂ production, oxygen consumption rate, and exothermicity, it was found that the coal pre-pyrolyzed with water content of 10.11% was easiest to self-heat, followed by the cases with water content of 5.96%, 13.92%, and 17.48%, respectively. The Pearson correlation coefficient method was adopted to conduct correlation analysis on values of ∆CO/∆O₂, CO/O₂, and CO₂/O₂ concentration with respect to coal exothermic intensity. It was found that the value of CO/O₂ concentration has the highest correlation with the exothermic intensity, which could be used as an index of exothermic degree in the stage of spontaneous combustion above 80°C.

摘要

为研究低温预热解过程中加水对煤自燃性的影响，通过程序加热实验，对不同水量的80℃等温热解预处理后的煤进行二次氧化特性测试。含量分别为 5.96%、10.11%、13.92% 和 17.48%。结果表明，在水分对CO ₂有正向影响的预热解过程中，CO和CO ₂的浓度随时间降低并趋于恒定。发布。80℃恒温预热抑制了煤的自燃，而预热解过程中水的存在则表现出促进和抑制煤自燃的竞争特性。从CO和CO ₂产生量、耗氧率、放热性等角度发现，含水量为10.11%的预热煤最容易自热，含水量为5.96%的煤次之，分别为 13.92% 和 17.48%。采用Pearson相关系数法对ΔCO/ΔO ₂、CO/O ₂和CO ₂ /O ₂值进行相关分析浓度与煤放热强度的关系。发现CO/O ₂浓度值与放热强度的相关性最高，可作为80℃以上自燃阶段放热程度的指标。