ABSTRACT
Crude oils contain significant quantities of sulfur, largely in the form of organic sulfur compounds. Sulfur in fuels causes corrosion of transportation and processing equipment, fouling of processing catalysts, and upon combustion, air pollution, in the form of particulate and acidic gas emissions (1). The concentration of sulfur in crude oil is typically between 0.05 and 5.0 wt. %, however, values as high as 13.95 wt. % have been reported (2). These values are impressive, considering that a crude oil with specific gravity of 0.9, and a sulfur content of 1.25 wt. %, contains 2 tons of elemental sulfur per thousand barrels of oil (2). In general, the distribution of sulfur in crude oil is such that the proportion of sulfur increases along with the boiling point of the distillate fraction. Organic sulfur compounds in the lower-boiling fractions of petroleum, e.g. the gasoline range, are mainly thiols, sulfides, and thiophenes. Higher-boiling fractions, e.g. the diesel and fuel oil range, contain thiols and sulfides as well, and in addition, significant amounts of benzothiophenes and dibenzothiophenes (DBTs).
