A Novel Method for Separation and Identification of Sulphur Compounds in Naphtha (30-200 C) and Middle Distillate (200-350 C) Fractions of Lloydminster Heavy Oil by GC/MS

Abstract

A procedure for the separation and identification of organic sulphur compounds from petroleum and related fractions has been investigated and applied to the naphtha (30–200°C) and a middle distillate fraction (200–350°C) of feed and processed Lloydminster heavy oils. The method permits the concentration of the sulphur compounds from a distillate fraction, although some aromatic hydrocarbons have been found in the sulphur compound concentrate. The separation method was developed using a mixture of model aliphatic and aromatic sulphides, thiophenes, and aromatic hydrocarbons of varied structure covering the investigated boiling range. The procedure employs liquid-solid chromatography, gas chromatography, and mass spectrometry. The sulphur compounds were concentrated in the aromatic fraction by chromatography on a silica gel column. The sulphur compound concentrate (sulphides and thiophenes) was obtained by chromatography of the aromatic fraction on a dual packed silica gel-alumina column using a pentane:ethyl acetate (95:5) mixture as eluent. The concentrate was then analyzed by gas chromatography/mass spectrometry. Twenty eight sulphur compounds were tentatively identified by mass spectrometry.