煤表面硫与氮官能团低温氧化规律XPS技术研究

XPS Research on Sulfur and Nitrogen Surface Functional Groups of Coal During Low-temperature Oxidation

利用XPS测试技术对兴成肥煤低温氧化规律进行实验研究。硫元素XPS氧化前后测试结果对比分析表明原煤硫元素中硫化物硫和硫铁矿硫占比最高,而有机硫中噻吩硫含量最高,其次为砜和亚砜。氧化后煤表面噻吩硫相对含量降低,有机硫中的部分硫化物硫氧化成亚砜,亚砜进一步氧化成砜,导致砜相对浓度增加,而亚砜缺失。原煤氮元素谱图分析可知兴成煤中氮主要存在于煤分子的边缘,约21%氮以季氮形式镶嵌于煤分子芳香结构中,煤中吡咯氮含量最高。氧化后XPS结果表明在氧化过程中与氮相连的氧原子脱除,氧化型氮转变为其他形态,且很大一部分转化为吡啶。

We use XPS technology to research Xinchen fat coal low temperature oxidation experiment. The XPS results of sulfur on the coal surface before and after oxidation show that the sulfide and pyrite content is highest for raw coal sample; thiophenic sulfur content is the highest in organic sulfur,followed by sulfoxide and sulfone; there is also some sulfate existing on the coal surface. The result of oxidized coal is different from raw sample; the relative contents of thiophenic sulfur is reduced; the sulfide oxide into sulfoxide which further oxidized to sulfone,that is the reason why sulfone relative concentration increased meanwhile sulfoxide disappeared. The nitrogen spectrogram of raw coal analysis shows that the nitrogen mainly exists on the edge of coal molecules; about 21% of nitrogen is embedded into coal molecular structure in the quaternary nitrogen form; the pyrrole nitrogen content is the highest. The XPS results of oxidation sample show that the oxygen atom linked to nitrogen removal in the process of oxidation; the oxidation nitrogen changes into other forms and most parts of it change into pyridine.