低温干燥对神华金烽矿煤结构和自燃性的影响

Low Temperature Drying Affected to Coal Structure and Spontaneous Combustion Nature in Shenhua Jinfeng Mine

为研究含水量高的低阶煤在低温干燥过程中的结构变化,以神华金烽矿煤为研究对象进行了大风量低温对流干燥试验,采用230℃以下的热空气作为干燥热源和介质,在热风流量2.0m3/min,干燥10 min的条件下用固定床干燥设备对煤脱水,并采用扫描电子显微镜(SEM)表征煤的表面形貌,用傅里叶变换红外光谱仪(FTIR)表征煤中化学键及官能团在干燥前后的变化。研究结果表明:170℃热空气可将煤中水分从30%降至15%以下;超过170℃的热空气在干燥过程中对煤的低温氧化作用严重,使煤的微观结构渐趋粉化,煤中桥键和侧链等官能团氧化消失,影响干燥后煤的自燃性。

In order to study the structure exchanged during the low temperature drying procedure of the low rank coal with a high water content, the Shenhua Jinfeng Mine coal were taken as the study objects for a high air flow and low temperature drying test. The hot air with a temperature under 230℃ was taken as the dry heat source and medium. With the hot air flow of 2.0 m^3/min and under the drying 10 min condition, a fixed bed drying equipment was applied to dewater the coal. The scanning electric microscope was applies to feature the surface appearance of the coal and fourier transform infrared spectrometer was applied to feature the exchanges before and after the drying of the chemical chain and the function group in the coal. The study results showed that 170 ℃ hot air could reduce the coal moisture from 30% to 15%. Over 170℃ hot air could have serious low temperature oxidized function during the drying procedure. The micron structure of the coal would be pulverized, the bridge chain and side chain and function of the coal would be oxidized and eliminated, which could influence the nature of coal after drying.