东北某露天矿褐煤干燥提质对水分复吸的影响

东北某露天矿褐煤因水分含量高,使用前需要进行干燥提质处理,以提高其燃烧热效率.为研究褐煤干燥提质后对水分复吸的影响,利用傅里叶变换红外光谱仪(Fourier transform infrared spectrometer,FTIR)、差热/热重分析仪(differential analysis/thermogravimetric analyzer,DTA/TG)、扫描电子显微镜(scanning electron microscope,SEM)等先进分析手段,结合干燥提质工艺,研究褐煤干燥提质对水分复吸的作用.结果 表明:东北某露天矿褐煤所含主要官能团包括:羟基、亚甲基、甲基、羰基、羧基和醚键.干燥提质后褐煤含水率由44.78％降至25.07％.干燥提质后褐煤静置9d后的含水率为25.75％,水分含量随时间增长无明显变化,水分吸附逐渐达到动态平衡.由于褐煤结构中的孔洞和裂隙减少,含氧官能团分解,干燥提质后褐煤对水分子的吸附能减弱,因此水分复吸不明显.干燥提质可以有效的抑制褐煤对水分子的吸附.

Effect of Lignite Upgrading by Drying on Water re-adsorption in an Open-pit Mine in Northeast China

In order to improve its combustion heat efficiency, it needed to be upgraded by drying progress before using for the high moisture content of lignite in an open-pit mine in Northeast China. Study of the effect of lignite upgraded by drying progress on moisture re-adsorption was of great significance to provide theoretical basis for lignite industrial application. Through the use of FTIR, DTA/TG, SEM and other advanced analysis methods, combined with drying technology, the effect upgrading on moisture re-adsorption was studied. The results show that the main functional groups contained in lignite include hydroxyl, methylene, methyl, carbonyl, carboxyl and ether bonds. After drying progress, the moisture content of lignite decreased from 44.78 wt.% to 25.07 wt.%. The moisture content of upgraded lignite after standing for 9 days is 25.75 wt.%. The moisture content did not change significantly with time, and the moisture adsorption gradually reached a dynamic equilibrium. After drying, the pores and cracks in the lignite structure are reduced, and the oxygen-containing functional groups are decomposed. After drying progress, the adsorption energy of the lignite to water molecules was weakened, so the water re-adsorption was not obvious. It is concluded that upgrading by drying progress can effectively inhibit the re-adsorption of water molecules by lignite.