Fuel oil, also called furnace oil, fuel consisting mainly of residues from crude-oil distillation. It is used primarily for steam boilers in power plants, aboard ships, and in industrial plants. Commercial fuel oils usually are blended with other petroleum fractions to produce the desired viscosity and flash point.
Furnace oil is a dark colored fuel, either distilled or residual fraction of crude oil that is extracted while petroleum distillation and is used for the purpose of generation heat and power. This fuel is sticky, thick and glutinous in nature. Furnace oil is known by the name of fuel oil internationally and also as bunker fuel. The fuel oil consists of lengthy chains of hydrogen and carbon mainly alkanes, cycloalkanes and aromatics. Basically furnace oil is termed for relatively heavier commercial extracts from crude oil.
Furnace oil is largely an industrial fuel. It acts as a key ingredient in the generation of electricity and heat in a number of production units. It has been used since a long time for such purposes and has gained much importance and inevitable value.