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Heavy Fuel Oil (HFO), It is also referred to as: Residual fuels (RM), FAME residual fuels (RF), is based on the high viscosity, tar-like mass, which remains after the distillation and subsequent cracking of crude oil in order to produce lighter hydrocarbon products, such as petrol, distillate diesel fuels and heating oil or feedstocks for lubricants. In short, Heavy Fuel Oil is the residual heavy oil after the extraction of gasoline and diesel oil from crude oil.
The main components are alkanes, cycloalkanes and different carbon hydrides. The boiling range is between 300°C and 700°C. The density of heavy oil is generally from 0.82 to 0.95, and the calorific value is around from 10,000 to 11,000 kcal/kg. Its characteristics are large molecular weight and viscosity. Due to its semi-fluid consistence, HFO has to be preheated to make it combustible in engines.
RM(RMA, RMB, RMD, RME, RMG, RMK) and RF are the international trade names.
Cheap, but challenging
As a residual product, HFO is a relatively inexpensive fuel – it typically costs 30% less than distillate fuels (MDO/MGO). It thus became the standard fuel for large marine diesel engines during the oil crisis in the 1970s and 1980s, and it required extensive adaptation of the injection system and other components of low and medium speed engines – which are still the only reciprocating engines capable of running on HFO.
Most of our medium speed liquid fuel engines can burn heavy fuel oil (HFO). Of course, our medium speed dual fuel engines are capable of burning HFO in liquid fuel mode as well.
For HFO quality requirement, Please click here to download: HFO Specification.
Remarks:
1) Engine inlet requirement: Additional parameters defined for ISO 8217. The entire ISO 8217:2024 document is mandatory. The fuel mixture at the engine inlet must be homogeneous. The fuel mixture is homogeneous if the p-value according to ASTM D7060 is at min. 1.20. Other processes (e.g. ASTM D7112 or ASTM D7157) can also be used to check the homogeneity of the fuel mixture. Furthermore, the fuel must be fit for use and must not contain substances in a concentration that contributes to further contamination of the air and/or may impair the safety of personnel or the performance of the machine.
2) Always reference the latest edition.
3) If FAME is present in the HFO (RF), the max. viscosity is limited to 500 mm2/s at 50°C. Specific requirements of the injection system must be taken into account.
4) When using RF (FAME according to EN 14214 or ASTM D6751* or their mixtures with HFO), prior consultation with Soar is required. The FAME must either be in accordance with EN 14214 or with ASTM D6751 as well as with increased oxidation stability of at least 8 hours (EN 15751).
5) According to ISO 8217:2024, the bunker product (before purification) may contain max. 0.50% water.
Note：To confirm whether the engine can use special types of fuel, please provide detailed fuel specifications.
