Sulfur compounds in petroleum

Petroleum with more than 2% sulfur content is called high sulfur petroleum, and petroleum with less than 0.5% sulfur content is called low sulfur petroleum. Most of China's crude oil belongs to low sulfur crude oil and sour crude oil. Most sulfur is concentrated in heavy distillates and residua.

Sulfur compounds in petroleum can be classified into:
Active sulfides: elemental sulfur, hydrogen sulfide and mercaptan.
Inactive sulfide: thioether, two sulfides and phenothiazide
Active sulfides are strongly corrosive to equipment.

The sulfur compounds in crude oil are mainly thioether and phenothiophene. The content of sulfur and hydrogen sulfide in crude oil is very little. Hydrogen sulfide is generally produced by the thermal decomposition of sulfide in crude oil, and hydrogen sulfide is oxidized to elemental sulfur. Therefore, elemental sulfur and hydrogen sulfide in crude oil are not necessarily inherent in crude oil.