高有机硫炼焦煤分选组分中硫的赋存形态及其热变迁行为研究

Sulfur occurrence and transformation during pyrolysis of the flotation fraction from coking coals with high organic sulfur

利用重介质分选法分别将两种高有机硫炼焦煤分选为密度范围不同的五个组分。采用X射线光电子能谱仪(XPS)、核磁共振波谱仪(13CNMR)和热解质谱联用技术(Py-MS)探究不同分选组分中硫的赋存形态及其热变迁行为。结果表明,不同分选组分中硫的分布、赋存形态及其所处化学环境存在显著差异。有机硫主要分布在低密度组分(D1)中,且以噻吩硫的形式存在;无机硫作为矿物质组分主要分布于高密度组分(D5)中。随着分选组分密度的增大,其脂肪碳的比例降低,芳香碳的比例增加,D1中硫醇、硫醚等硫化物的含量明显增加。热解过程中脂肪碳结构裂解生成的挥发分促进含硫气体的释放,进而提高了D1的脱硫效率,D5中硫的热变迁行为则主要受煤中矿物质的影响。

Two coking coals with high organic sulfur were separated into five fractions with different density ranges by heavy medium separation.The occurrences and transformation of sulfur during pyrolysis of different fractions were investigated by X-ray photoelectron spectroscopy(XPS),solid state 13C nuclear magnetic resonance(13C NMR)and pyrolysis mass spectrometry(Py-MS).The results show that different fractions have significant differences in distribution,occurrence,and chemical environment of sulfur.Organic sulfur is mainly distributed in the low density fraction(D1)and exists in the form of thiophene.Inorganic sulfur such as mineral component is mainly distributed in the high density fraction(D5).As the increase of density of coal fraction,the proportion of aliphatic carbon decreases,and aromatic carbon increases,as well as content of mercaptan and thioether in D1 increases greatly.The volatiles are greatly released since decomposition of aliphatic carbon structure during pyrolysis,which promotes the release of sulfur containing gases,and then improves desulfurization efficiency of D1.However,transformation of sulfur is mainly affected by minerals during D5 pyrolysis.