低阶煤低温干燥官能团的演变

TRANSITION OF FUNCTIONAL GROUPS OF LOW RANK COAL AT LOW TEMPERATURE

利用傅立叶红外对低温干燥前后低阶煤中官能团的演变进行了研究,并通过红外谱图的峰面积曲线拟合处理,分析了低阶煤中各官能团在干燥过程中的变化规律及干燥后低阶煤性质的演变.结果表明,在干燥过程中,随着温度的增加,脂肪族结构逐渐消失,脂肪侧链中亚甲基官能团比甲基官能团活泼,在干燥过程中最先被氧化;含氧官能团羧基、羟基、羰基及醚键含量均呈现降低趋势,其中羧基反应活性最好,其含量降低的速度最快,羰基性质最为稳定,其含量变化最为缓慢;芳香环CC先增加后减少,伊敏煤中CC在230℃时开始分解,天池能源煤中CC在190℃时已开始大量分解.研究表明,在低温干燥过程中低阶煤的变质程度有所增加,可在一定程度上提高其煤阶.

The low rank coals before and after low temperature drying process were characterized using Fourier-transform infrared spectrometer. Variations in the main functional groups of the low rank coals before and after the drying process were analyzed based on the curve- fitting analysis. It was found that the aliphatic hydrocarbons in the coals after the drying process disappear gradually with the increasing drying temperature. Compared with the methyl groups, the methylene groups with higher activity were preferably oxidized in the low temperature drying process. The main oxygen functional groups containing the carboxyl groups, hydroxyl groups, carbonyl groups and ethers decrease with the increasing drying temperature. The carboxyl groups decrease quickly with the increasing drying temperature and the carbonyl groups are more stable than the other functional groups. The aromatic C-C groups of Yimin （YM） coal decompose at 230 ℃. While, the aromatic C-C groups of Tianchinengyuan （TC） coal decompose at 190 ℃. It can be deduced that the metamorphic grade of low rank coal increases with the increasing temperature during the drying process, which improve the coal rank to some extent.