Operating Principles - Wartsila ?31DF Series Product Manual

Wärtsilä 31DF Product Guide
The fuel should not include any added substance, used lubricating oil or chemical waste,
which jeopardizes the safety of installations or adversely affects the performance of the engines
or is harmful to personnel or contributes overall to additional air pollution.
6.2

Operating principles

Wärtsilä 31DF engines are usually installed for dual fuel operation meaning the engine can be
run either in gas or diesel operating mode. The operating mode can be changed while the
engine is running, within certain limits, without interruption of power generation. If the gas
supply would fail, the engine will automatically transfer to diesel mode operation (MDF).
DBAE248994
a) 1 mm²/s = 1 cSt
b) Max. 1010 kg/m³ at 15 °C, provided the fuel treatment system can reduce water
and solids (sediment, sodium, aluminium, silicon, calcium, potassium, magnesium)
before engine to the specified levels.
c) Notwithstanding the limits given, the purchaser shall define the maximum sulphur
content in accordance with relevant statutory limitations.
d) Fuel temperature in the whole fuel system including storage tanks must be kept
during stand-by, start-up and operation 10 – 15 °C above the cloud point in order
to avoid crystallization and formation of solid waxy compounds (typically paraffins)
causing blocking of fuel filters and small size orifices. Additionally, fuel viscosity
sets a limit to cloud point so that fuel must not be heated above the temperature
resulting in a lower viscosity before the injection pumps than specified above.
e) Viscosity of different crude oils varies a lot. The min. limit is meant for low viscous
crude oils being comparable with distillate fuels. The max. limit is meant for high
viscous crude oils being comparable with heavy fuels.
f) The ashing temperatures can vary when different test methods are used having
an influence on the test result.
b) if not within the given limits, the maximum sulphur content to be defined in
accordance with relevant statutory limitations.
c) It shall be ensured that the pour point is suitable for the equipment on board,
especially if the ship operates in cold climates.
d) If the sample is not clear and bright, the total sediment by hot filtration and water
tests shall be required.
e) If the sample is not clear and bright, the test cannot be undertaken and hence
the oxidation stability limit shall not apply.
f) If the sample is not clear and bright, the test cannot be undertaken and hence
the lubricity limit shall not apply.
g) The requirement is applicable to fuels with a sulphur content below 500 mg/kg
(0.050 % mass).
h) Additional properties specified by Wärtsilä, which are not included in the ISO
specification.
i) If the sample is dyed and not transparent, then the water limit and test method
ISO 12937 shall apply.
NOTE
NOTE
6. Fuel Oil System
6-9