N, O, and S functional groups in residue asphaltene before and after hydrotreating via X-ray technology

ABSTRACT

Asphaltene of Tahe atmospheric residue was studied before and after hydrotreating. Functional groups in asphaltene were quantitatively and qualitatively investigated via X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy. After hydrotreating, pyrrole nitrogen in asphaltene decreased from 97.65% to 92.26%, while pyridine increased from 2.35% to 7.74%. Before hydrotreating, 93.69% of the oxygen functional group was in the form of C‒O bonds, and 6.31% were C˭O double bonds. Then, C‒O and C˭O converted into a COO structure, with a content of 30.25%. For sulfur, the desulfurization effect was obvious, since the thiophene sulfur and sulfoxide were both reduced.

KEYWORDS:

• atmospheric residue hydrotreating
• asphaltene
• heteroatom functional groups
• XANES
• XPS

Funding

This study was supported by the Scientific Research Starting Fund from Shengli College China University of Petroleum.