Viscosity: D6 fuel has a high viscosity, so it can’t be used in smaller engines or vehicles that can’t be preheated.
Pollutants: D6 fuel contains high levels of pollutants, such as sulfur.
Preheating: D6 fuel needs to be preheated to a temperature of 220–260°F (104–127°C) before it can be used.
Marine Industry: Primary fuel for large ships and vessel bunkering.
Power Generation: Used in industrial generators and boilers.
Heavy Machinery: Suitable for preheated engines in industrial applications.
Bunker fuel specifications can vary depending on the type of fuel and the standards set by organizations like the International Maritime Organization (IMO) or regional regulations. Below is a general overview of the specifications for the most common bunker fuel grades:
| Density @ 15°C | 980–1010 kg/m³ |
| Viscosity @ 50°C | 180–700 cSt |
| Sulfur Content | Up to 3.5% (pre-IMO 2020) — now 0.5% in most regions |
| Flash Point | Min. 60°C |
| Pour Point | -6°C to 24°C |
| Carbon Residue | Up to 18–22% |
| Ash Content | Up to 0.2% |
| Water Content | Up to 1.0% |
| Density @ 15°C | 900–990 kg/m³ |
| Viscosity @ 50°C | 10–180 cSt |
| Sulfur Content | Max. 0.5% (IMO 2020 compliant) |
| Flash Point | Min. 60°C |
| Pour Point | -6°C to 24°C |
| Carbon Residue | Up to 10–15% |
| Ash Content | Up to 0.1% |
| Water Content | Up to 0.5% |
| Density @ 15°C | 820–900 kg/m³ |
| Viscosity @ 40°C | 2–6 cSt |
| Sulfur Content | Max. 0.1% (ECA) or 0.5% (outside ECA) |
| Flash Point | Min. 60°C |
| Pour Point | -6°C to 0°C |
| Carbon Residue | Up to 0.3% |
| Ash Content | Up to 0.01% |
| Water Content | Up to 0.1% |