渣油加氢转化前后沥青质的分子组成变化

Characterization of the molecular composition of asphaltene from heavy petroleum residue before and after hydrotreating

沥青质是造成渣油加氢过程中结焦和催化剂失活的主要因素,深入研究渣油加氢转化前后沥青质的分子组成变化对于改进渣油加氢工艺有着重要的指导意义.本文采用傅里叶变换离子回旋共振质谱仪(FT-ICR MS)研究了塔河减渣加氢转化过程中沥青质组分的分子组成差异.为了减少沥青质分子之间的相互干扰和抑制,通过固相萃取技术对渣油加氢前后得到的沥青质进行了分离,并对比了其中主要化合物在分离前后的详细分子组成.利用固相萃取技术分离之后,还可以对加氢后沥青质中微量的卟啉钒化合物进行富集,并研究了在渣油加氢前后沥青质中的卟啉钒化合物的分子组成变化.研究表明,对沥青质样品进行更细致的分离可以得到丰富、全面的沥青质分子组成数据,为石油加工提供更有价值的分子结构信息.

Asphaltene is the main source of coking and catalyst deactivation during hydrotreating of heavy oils, and the variation of molecular composition of asphaltene during hydrotreating is crucial for improving the refining processes of heavy oils. In this work, asphaltene obtained from Tahe vacuum residue was characterized by Fourier transform ion cyclotron resonance mass spectrometry（FT-ICR MS） before and after hydrotreating. The asphaltene samples were separated by solid-phase extraction（SPE） to reduce the matrix effect and ionization suppression, and the sub fractions were also measured by FT-ICR MS. It was also found that vanadyl porphyrins was enriched by SPE method, making the detection of trace amount of vanadyl porphyrins possible after hydrotreating. The structural differences of vanadyl porphyrins during hydrotreating were studied by FT-ICR MS. It is proved in this work that pre-separation is helpful for providing comprehensive molecular composition of asphaltene samples, which is valuable for refining industry.