Fueloil

Fueloil, or fuel oil, is a petroleum-derived liquid used primarily for heating, power generation, and marine propulsion. It is produced during the refining of crude oil and comprises a range of distillates and residual oils that vary in viscosity, sulfur content, and energy density. In some markets the term fueloil is used interchangeably with fuel oil, though regional naming conventions may distinguish heating oils from marine fuels.

The common grades are No. 1 fuel oil and No. 2 fuel oil. No. 1 is a lighter, kerosene-type distillate used in some heating systems and portable equipment; No. 2 is a heavier distillate used for home heating, some diesel engines, and industrial furnaces. Heavier grades—No. 4, No. 5, and No. 6—are residual fuels, with No. 6 primarily used as bunker fuel for ships. In marine and industrial contexts, terms such as bunker C may be encountered. Specifications and sulfur limits are set by regional standards (for example ASTM D396 in the United States and various European norms).

Production and handling: fueloil is obtained by fractional distillation of crude oil and, for heavier grades, by vacuum distillation and upgrading processes such as hydrocracking. Fuels are often blended to meet viscosity, pour-point, and sulfur requirements. Storage and handling require containment and temperature control; fuels are flammable and can pose environmental and health risks if spilled or improperly burned.

Environmental and regulatory aspects: combustion of fueloil releases pollutants including sulfur oxides, nitrogen oxides, particulate matter, and carbon dioxide. Regulations increasingly limit sulfur content in fuels and impose stricter emissions controls, particularly for marine fuels and stationary sources.