Fuel Oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. the term Fuel Oil is also used in a stricter sense to refer only to the heaviest commercial fuel that can be obtained from crude oil, heavier than gasoline and naphtha. Application: Cracked fuel oils are used as fuel for power generation, marine bunkers, and large industrial heating plants. Generally categorized between high and low-sulphur grades, with the latter containing less than 1.0 % sulphur by weight.