委内瑞拉稠油沥青质的XPS研究

Study on XPS of Venezuela Heavy Oil Asphaltene

以委内瑞拉稠油沥青质为原料,采用X射线光电子能谱(XPS)定性和定量分析了沥青质表面含碳、氧、氮、硫官能团结构和含量。结果表明,委内瑞拉稠油沥青质表面的碳原子主要以C—C和C—H形式存在,约5%的碳原子与氧原子结合;含氧官能团中羰基为主要含氧结构,其氧原子数量占氧原子总数量的44%左右,C—O和COO的氧原子数量分别占氧原子总数量的29%和27%;含氮官能团中,约59%的氮为弱碱性或非碱性的吡咯类氮,剩余为强碱性的吡啶类氮;含硫官能团中,脂肪类硫约占57%,其余为噻吩类硫。从委内瑞拉稠油沥青质表面杂原子官能团摩尔数量来看,羰基摩尔分数最多(>1%),其次是吡咯氮和脂肪硫(均约1%),C—O基、羧基、吡啶氮和噻吩硫摩尔分数基本相同(均约0.7%)。

The functional groups containing C, O, N and S on the surface of Venezuela heavy oil asphaltene were investigated quantitatively and qualitatively by X-ray photoelectron spectroscopy （XPS）. The results showed that on the surface of Venezuela heavy oil asphaltene carbon atoms existed mainly as the forms of C-C and C-H. There were almost 5% of carbon atoms combining with oxygen atoms, in which the carbonyl was the main oxygen-containing groups with oxygen atoms accounting about 44%, while the C-O and COO groups with oxygen atoms accounting 29% and 27% of total oxygen atoms, respectively. In nitrogen-containing groups, 59% of nitrogen atoms were weak basic or non-basic pyrrolic nitrogen and the remainder was strong basic pyridinic nitrogen. In sulfur-containing groups, 57% of sulfur were aliphatic sulfur, the others were thiophenic sulfur atoms; From the standpoint of hetero-atomic functional groups moles of Venezuela heavy oil asphaltene, the molar fraction of carbonyl was the most, beyond 1%, the molar fractions of pyrrolic nitrogen and aliphatic sulfur were less than that of carbonyl, both of which were about 1%, and the molar fractions of C-O, carboxyl, pyridinic nitrogen and thiophenic sulfur were almost the same, which were all about 0. 7%,