In the maritime industry the following type of classification is used for marine fuel oils:
- MGO (Marine gas oil) – roughly equivalent to No. 2 fuel oil, made from distillate only
- MDO (Marine diesel oil) – A blend of heavy gasoil that may contain very small amounts of black refinery feed stocks, but has a low viscosity up to 12 cSt/400 C so it need not be heated for use in internal combustion engines
- IFO (Intermediate fuel oil) A blend of gasoil and heavy fuel oil, with less gasoil than marine diesel oil
- MFO (Marine fuel oil) – same as HFO (just another “naming”)
- HFO (Heavy fuel oil) – Pure or nearly pure residual oil, roughly equivalent to No. 6 fuel oil
Marine diesel oil contains some heavy fuel oil, unlike regular diesels. Also, marine fuel oils sometimes may contain waste products such as used motor oil.
Standards and classification
Marine fuels were traditionally classified after their kinematic viscosity. This is a mostly valid criteria for the quality of the oil as long as the oil is made only from atmospheric distillation. Today, almost all marine fuels are based on fractions from other more advanced refinery processes and the viscosity itself says little about the quality as fuel. CCAI and CII are two indices which describe the ignition quality of residual fuel oil, and CCAI is especially often calculated for marine fuels. Despite this marine fuels are still quoted on the international bunker markets with their maximum viscosity (which is set by the ISO 8217 standard – see below) due to the fact that marine engines are designed to use different viscosities of fuel.[1]. The unit of viscosity used is the Centistoke and the fuels most frequently quoted are listed below in order of cost, the least expensive first-
- IFO 380 – Intermediate fuel oil with a maximum viscosity of 380 Centistokes/500 C
- IFO 180 – Intermediate fuel oil with a maximum viscosity of 180 Centistokes/500 C
- LS 380 – Low-sulphur (<1.5%) intermediate fuel oil with a maximum viscosity of 380 Centistokes/500 C
- LS 180 – Low-sulphur (<1.5%) intermediate fuel oil with a maximum viscosity of 180 Centistokes/500 C
- MDO – Marine diesel oil.
- MGO – Marine gasoil.
The density is also an important parameter for fuel oils since marine fuels are cleaned by centrifugal type separators before use to remove water and dirt from the oil. Since the separators use centrifugal force, the oil must have a density which is sufficiently different from water. Conventional type separators of purifier type have a maximum density limit of 991 kg/m3/150 C ; with modern High Density type separators it’s possible to clean fuel oils with a maximum density of 1010 kg/m3/150 C.
The first British standard for fuel oil came in 1982. The latest standard is ISO 8217 from 2005. The ISO standard describe four qualities of distillate fuels and 10 qualities of residual fuels. Over the years the standards have become stricter on environmentally important parameters such as sulfur content. The latest standard also banned the adding of used lubricating oil (ULO).
ISO 8217 Fuel Standard Fourth Edition (source: DNV & ISO)
MARINE DISTILLATE FUELS
| Parameter | Unit | Limit | DMX | DMA | DMZ | DMB |
|---|---|---|---|---|---|---|
| Viscosity at 40°C | mm²/s | Max | 5.500 | 6.000 | 6.000 | 11.00 |
| Viscosity at 40°C | mm²/s | Min | 1.400 | 2.000 | 3.000 | 2.000 |
| Micro Carbon Residue at 10% Residue |
% m/m | Max | 0.30 | 0.30 | 0.30 | – |
| Density at 15°C | kg/m3 | Max | – | 890.0 | 890.0 | 900.0 |
| Micro Carbon Residue | % m/m | Max | – | – | – | 0.30 |
| Sulphur a | % m/m | Max | 1.00 | 1.50 | 1.50 | 2.00 |
| Water | % V/V | Max | – | – | – | 0.30b |
| Total sediment by hot filtration | % m/m | Max | – | – | – | 0.10b |
| Ash | % m/m | Max | 0.010 | 0.010 | 0.010 | 0.010 |
| Flash point | 0°C | Min | 43.0 | 60.0 | 60.0 | 60.0 |
| Pour point, Summer | 0°C | Max | 0 | 0 | 0 | 6 |
| Pour point, Winter | °C | Max | -6 | -6 | -6 | 0 |
| Cloud point | °C | Max | -16 | – | – | – |
| Calculated Cetane Index | Min | 45 | 40 | 40 | 35 | |
| Acid Number | mgKOH/g | Max | 0.5 | 0.5 | 0.5 | 0.5 |
| Oxidation stability | g/m3 | Max | 25 | 25 | 25 | 25 c |
| Lubricity, corrected wear scar diameter (wsd 1.4 at 60°C d | um | Max | 520 | 520 | 520 | 520 c |
| Hydrogen sulphide e | mg/kg | Max | 2.00 | 2.00 | 2.00 | 2.00 |
| Appearance | Clear & Bright f | b, c | ||||
| a | A sulphur limit of 1.00% m/m applies in the Emission Control Areas designated by the International Maritime Organization. As there may be local variations, the purchaser shall define the maximum sulphur content according to the relevant statutory requirements, notwithstanding the limits given in this table. | |||||
| b | If the sample is not clear and bright, total sediment by hot filtration and water test shall be required. | |||||
| c | Oxidation stability and lubricity tests are not applicable if the sample is not clear and bright. | |||||
| d | Applicable if sulphur is less than 0.050% m/m. | |||||
| e | Effective only from 1 July 2012. | |||||
| f | If the sample is dyed and not transparent, water test shall be required. The water content shall not exceed 200 mg/kg (0.02% m/m). | |||||
MARINE RESIDUAL FUELS
| Parameter | Unit | Limit | RMAa | RMB | RMD | RME | RMG | RMK | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 10 | 30 | 80 | 180 | 180 | 380 | 500 | 700 | 380 | 500 | 700 | |||
| Viscosity at 50°C | mm²/s | Max | 10.00 | 30.00 | 80.00 | 180.0 | 180.0 | 380.0 | 500.0 | 700.0 | 380.0 | 500.0 | 700.0 |
| Density at 15°C | kg/m3 | Max | 920.0 | 960.0 | 975.0 | 991.0 | 991.0 | 1010.0 | |||||
| Micro Carbon Residue | % m/m | Max | 2.50 | 10.00 | 14.00 | 15.00 | 18.00 | 20.00 | |||||
| Aluminium + Silicon | mg/kg | Max | 25 | 40 | 50 | 60 | |||||||
| Sodium | mg/kg | Max | 50 | 100 | 50 | 100 | |||||||
| Ash | % m/m | Max | 0.040 | 0.070 | 0.100 | 0.150 | |||||||
| Vanadium | mg/kg | Max | 50 | 150 | 350 | 450 | |||||||
| CCAI | – | Max | 850 | 860 | 870 | ||||||||
| Water | % V/V | Max | 0.30 | 0.50 | |||||||||
| Pour point (upper) b, Summer | °C | Max | 6 | 30 | |||||||||
| Pour point (upper) b, Winter | °C | Max | 0 | 30 | |||||||||
| Flash point | °C | Min | 60.0 | ||||||||||
| Sulphur c | % m/m | Max | Statutory requirements | ||||||||||
| Total Sediment, aged | % m/m | Max | 0.10 | ||||||||||
| Acid Number e | mgKOH/g | Max | 2.5 | ||||||||||
| Used lubricating oils (ULO):
Calcium and Zinc; or Calcium and Phosphorus |
mg/kg | – | The fuel shall be free from ULO, and shall be considered to contain ULO when either one of the following conditions is met:
Calcium > 30 and zinc >15; or |
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| Hydrogen sulphide d | mg/kg | Max | 2.00 | ||||||||||
| a | This residual marine fuel grade is formerly DMC distillate under ISO 8217:2005. | ||||||||||||
| b | Purchasers shall ensure that this pour point is suitable for the equipment on board, especially in cold climates. | ||||||||||||
| c | The purchaser shall define the maximum sulphur content according to the relevant statutory requirements. | ||||||||||||
| d | Effective only from 1 July 2012. | ||||||||||||
| e | Strong acids are not acceptable, even at levels not detectable by the standard test methods for SAN. As acid numbers below the values stated in the table do not guarantee that the fuels are free from problems associated with the presence of acidic compounds, it is the responsibility of the supplier and the purchaser to agree upon an acceptable acid number. |
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Hi
What is the difference between MGO and High Speed Diesel oil in terms of usage and specifications?
I am not sure what high speed diesel as it is not any “common term” for in maritime so I guess I cannot be of any help in this case.
Maybe there are any other reader that could give you a better reply!?
/admin
Gents,
Would any body highlight MGO reports with LDO?
Can MGO be turn to LDO?
Please advise.
thanks & Rgds,
Dilip