Sulfur in petroleum boiling range
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Sulfur is present throughout the distillation range of petroleum, except in the lightest components. How should this sentence be interpreted? Could the forum members help answer it?
There are many types of sulfur-containing compounds, with varying boiling points and amounts
Sulfides in petroleum fractions are quite complex; the lightest one is likely methanethiol, with a boiling point of less than 10°C. As the fractions become heavier, the sulfides contained within them also become heavier
The sulfur content in different oils varies greatly, ranging from a few parts per ten thousand to several percent. The distribution of sulfur in petroleum fractions generally increases as the boiling range of the fractions rises, with most of the sulfur concentrated in heavy fractions and residue. The forms of sulfur present in petroleum include elemental sulfur, hydrogen sulfide, thiol, thioether, cyclic thioether, disulfide compounds, thiophene and its homologs, etc. Elemental sulfur, hydrogen sulfide, and low-molecular-weight thiol compounds can all react with metals, causing corrosion of metal equipment; they are collectively referred to as reactive sulfides. Thiethers are sulfur compounds that are present in large quantities in petroleum. The content of disulfides is low, mostly concentrated in the high-boiling fractions. Thiethers and disulfides are neutral liquids that do not cause corrosion to metals; however, they decompose into reactive sulfides at high temperatures. Thiophenes and their derivatives have high stability and constitute the main class of sulfur-containing compounds in petroleum.