12.11.3.2
Density
The composition of the fuel gives the density. A high density shows a high aromatic content. It is
not always possible to use conventional methods to measure the density at 15°C. Thus, the
measurement is made at a higher temperature and then converted and adjusted to the reference
temperature. Usually the maximum density of fuel is 991.0 kg/m
3
related to the ISO 8217:2017
RMG specifications. If you use a fuel with a density higher than 991.0 kg/m
3
, you must make sure
that an equipment is available on board that can treat such fuels.
12.11.3.3
Calculated Carbon Aromaticity Index (CCAI)
The ignition and combustion properties of the fuel in a diesel engine are related to the specific
engine design, load profile and fuel properties.
The CCAI is a calculated value of the ignition properties or ignition delay of the fuel related to the
viscosity and density. The CCAI gives no indication of the combustion properties. The CCAI limit
is useful to examine fuels with unusual density-viscosity relations.
12.11.3.4
Sulphur
Sulphur limits are not specified in ISO 8217:2017 because statutory specifications put a limit on
this value. WinGD 2-stroke engines are designed to operate with high and low sulphur fuels, if:
•
You select the alkalinity (base number (BN)) of the cylinder oil in relation to the sulphur
content of the fuel in use.
•
You use the necessary equipment related to the statutory specifications.
12.11.3.5
Flash point
The flash point is an important safety and fire hazard parameter for diesel fuels. Fuel is always a
fire hazard. There can be flammable vapors in the air space above the remaining fuel in the tanks.
Take care if you increase the temperature of the remaining fuel above the flash point, as flammable
vapor can occur.
12.11.3.6
Hydrogen sulphide (H
2
S)
Hydrogen Sulphide (H
2
S) is a very toxic gas and exposure to high concentrations is dangerous
and can kill you. Be careful when tanks or fuel lines are opened because there can be H
2
S vapor.
At low concentrations H
2
S smells almost the same as bad eggs. You cannot sense H
2
S at
moderate concentrations. H
2
S causes nausea and dizziness.
12.11.3.7
Acid number
Fuels with high acid numbers can cause damages to fuel injection systems. Most fuels have a low
acid number, which is not dangerous, but an acid number above 2.5 mg KOH/g, can cause
problems. Some naphthenic fuels can have an acid number of more than 2.5 mg KOH/g, but still
be permitted. Only a full laboratory analysis can find the strong acid number.
12.11.3.8
Sediment, Carbon and Asphaltenes
High quantities of sediment, carbon and asphaltenes decrease the ignition and combustion quality
of the fuel and increase wear and damage to engine components. Asphaltenes also have an effect
X52
AA00-0000-00AAA-030A-A
Operation Manual
Diesel engine fuels
Winterthur Gas & Diesel Ltd.
- 479 -
Issue 002 2018-11
