Marine low viscosity fuel is used for refuelling of vessels power equipment. It is often called marine solar oil. Marine fuel properties are significantly inferior compared to diesel fuel because of the small cetane number (up to 45) and high sulfur content. Such fuel cannot be used in diesel vehicles, since the risk of damage of the fuel system is high.
Classification of marine fuel is based on many criteria (similar to DF). If before viscosity was the main parameter, today, when heavy suspensions are included in the fuel due to increased oil refining efficiency, a more detailed description of the marine fuel is needed to meet the quality requirements.
World standards, including GOST, set strict requirements for the 4th class of marine distillate fuels and 11 residual fuels. They are defined by alphabetic letters with a number. The letters correspond to the distillates (DM) and residual fuel oil (RF). The number shows the maximum viscosity at 50 ° C.
In the sequence of deterioration in quality distillate types are as follows: DMX, DMA, DMZ, DMB The DMX type is the closest to diesel fuel and is considered to be its analogue.
Foreign standards for marine fuel such as ISO, BSI, CIMAC are widely used. They set the basic parameters of low-viscosity marine fuel:
1. Fuel viscosity.
Indicates internal friction, the ability to resist to the particles movement. Viscosity affects the combustion of marine fuel and provides uninterrupted operation of the fuel system. The viscosity of the fuel reduces during heating.
The kinematic viscosity norm ranges from 1.4-5.5 mm2 / s1 for DMX class to 11.0 mm2 / s1 for DMB
2. Sulfur content
Exceeding of sulfur content in the fuel augments corrosion of the fuel system parts. Sulfur content in marine fuel is higher than in diesel fuel, which makes it unacceptable for use in car engines.
There are the following types of low viscosity marine fuel depending on sulfur content:
- up to 0.5% – fuel for diesel generators;
- up to 1% – for domestic needs and agricultural equipment;
- up to 1,5% – marine fuel TU 38.101567 for heating boilers.
According to the norms, the presence of sulfur shall not be more than 1% for DMX, not more than 1.5% for DMA, DMZ and not more than 2% for DMB.
3. Density
Density describes the fractional composition, volatility and chemical properties of the fuel. During purification of fuel, it is possible to separate it from water due to the its different density.
Norms of density of low viscosity marine fuel at a temperature of 15 ° C are 0.890 – 0.900 kg / cc. m.
4. Cocking.
Cooking ability is measured by the solid residue from fuel combustion. Its value indicates the percentage of incomplete combustion of fuel. Distillate brands of low viscosity marine fuel has a low percentage (0.3-0.5%), and the residuals can have up to 22%. The coke residue indicator is directly proportional to the density and inversely proportional to the quality of the fuel.
5. Ash content
The ash content depends on the presence of non-combustible impurities. Often these are natural elements of extracted oil, but even more often they appear during the distillation process, long storage and transportation of fuel. For light distillates, the maximum mass ash fraction is not more than 0.1%, and for heavy residuals – not more than 0.2%.
Marine low viscosity fuel should not contain inorganic acids, used lubricating oils, bio components, additives and mechanical wastes. Fuel compliance with the world standards is important for the safe use of vessels, personnel health and environmental protection.
