Definition - What does Bunker Oil mean?
Bunker oil is oil loaded into bunker tanks for use as fuel, as distinguished from oil carried as cargo.
Bunker oils contain metals and contaminants that can cause corrosion in commercial ships, cruise ships and cargo. Since it carries a range of contaminants, it can lead to a serious environmental hazard when it spills.
Bunker oil is also known as residual fuel oil (RFO).
Corrosionpedia explains Bunker Oil
Bunker oil is residual fuel oil of high viscosity commonly used in marine and stationary steam power plants. It requires preheating to 220 - 260 °F (104 - 127 °C). In comparison with other petroleum products, bunker oil is extremely crude and highly polluting.
Bunker oil is less useful than other types of oil because it is so viscous that it must be heated with a special heating system before use and it contains relatively high amounts of pollutants, particularly sulfur, which forms sulfur dioxide upon combustion.
Heavier petroleum products like diesel and lubricating oil precipitate out more slowly, and bunker oil is literally the bottom of the barrel; the only thing denser than bunker fuel is the residue which is mixed with tar for paving roads and sealing roofs.
Although bunker oil is extremely cheap, many oil spills have involved bunker oils, leading some environmental organizations to call for a ban on the substance. Because it is so dense, it is extremely difficult to clean up and it easily coats animals and shorelines.