高硫石油焦热解过程及硫形态的变化特性

Research on pyrolysis process of high sulfur petroleum coke and the changes of sulfur species

在管式炉实验装置上进行不同温度高硫石油焦N_2气氛热解实验,并利用X射线光电子能谱分析(XPS)技术进行表征,深入分析高硫石油焦热解过程中硫形态变化特性,同时采用热重-红外联用(TG-FTIR)技术深入分析热解过程。热重分析结果表明,高硫石油焦热解经历了干燥脱水阶段,长链脂肪烃、稠环芳香烃等组分分解阶段,在430℃和635℃失重速率达到最大形成失重峰。红外分析结果表明,高硫石油焦热解释放气体主要包括CO_2、CH_4、H_2O、SO_2、芳烃化合物和脂肪族化合物等,并且在不同温度区间释放气体组成有着巨大的差异。XPS分析结果表明,高硫石油焦表面硫含量及存在形态与热解温度紧密关联,随着热解温度的不断升高,高硫石油焦表面硫含量在700℃达到最大值,不同硫形态之间发生相互转化。

Pyrolysis experiments of high sulfur petroleum coke under N2 atmosphere at different temperatures were conducted in a tube furnace. TG-FTIR test was carried out to analyze the pyrolysis process and the transformation of sulfur species during the pyrolysis process was characterized by XPS. TG/DTG resulted show that the pyrolysis process experienced dehydration,decomposition of long chain aliphatic hydrocarbon and fused ring aromatic hydrocarbon stages,with the maximum rate of weight loss at 430℃ and 635℃ respectively. The FTIR analysis showed that the gas-phase products from the pyrolysis process mainly included CO2,CH4, H2O,SO2,aromatic compounds,aliphatic compounds and so on. In addition,the gas components that released at different temperatures showed great difference. The XPS analysis showed that the total sulfur content and the species on the surface of high sulfur petroleum coke were associated with the pyrolysis temperature. To be specific,the total sulfur content on the surface increased with the temperature,reaching a maximum value at 700℃,and the mutual conversion among different sulfur species occurred during the pyrolysis process.