煤炭微波脱硫中硫、碳、氧化学形态变化的XPS分析

XPS analysis on the changes in chemical forms of C,S and O in coal during microwave desulfurization

为了研究微波脱硫中,煤炭表面主要元素的变化机制,以碱液为助剂,对一种高硫烟煤进行了微波脱硫实验,并利用X射线光电子能谱(XPS)分析了微波脱硫前、后煤样表面硫,碳和氧等主要元素的化学形态及对应原子数分数的变化。研究结果表明:在碱液辅助下,煤炭微波脱硫率达到23.80%;经微波脱硫后,煤中以C―C、C―H形式存在的碳原子数减少,以C═O、COO―形式存在的碳、氧原子数分数增大,低价态的有机碳被氧化为高价态碳;而对于各有机硫的赋存形式,硫醇、硫醚的物质的量含量下降,噻吩比例上升,并有硫酸盐生成,硫元素被氧化。

In order to study the change mechanism of the main elements in coal surface during the microwave desulfurization,microwave desulfurization experiment was carried out using a kind of high sulfur bituminous coal in the presence of alkali solution as the assistant reagent.The changes of chemical forms and relative contents of dominant elements in coal,such as S,C and O,were analyzed before and after microwave desulfurization by X-ray photoelectron spectroscopy（XPS）.The results show that sulfur in the coal can be effectively removed by 23.80% under the chosen experiment conditions.After microwave desulfurization,the relative contents of C—H and C—C decrease while the contents of elements C and O that existingincoalwith C—O and COO— forms increase,suggesting that organic carbon with low chemical valence has been oxidized to higher valence carbon.The contents of mercaptan and sulfoether decrease down with the increasing of the relative content of thiophene,and part of sulfure were oxidized to sulfatic sulfur.