WÄRTSILÄ Vasa R22, Instruction Manual

Page: 21 / 297

02. Fuel, Lubricating Oil, Cooling Water
02.1 Fuel
02.1.1 General
The engine is designed to operate on heavy fuel (residual fuel)
with a maximum viscosity of 55 cSt/100°C (approx. 730 cSt/50°C,
approx. 7200 sec. RI/100°F) and will operate satisfactorily on
blended (intermediate) fuels of lower viscosity, as well as on
distillate fuel. Avoid the use of fuels having a lower viscosity than
about 2.8 cSt at 40°C as such fuels may cause fuel injection pump
plunger or fuel nozzle needle seizure.
The maximum limits of fuel characteristics for a certain engine
are stated in the sales contract.
Blended fuels (residuals and distillate) with a viscosity between
approx. 4 and 7 cSt/100°C (12 and 30 cSt/50°C, 65 and 200 sec.
RI/100°F) containing between 30 and 60 % distillate should,
however, be avoided due to the risk of precipitation of heavy
components in the blend, with filter clogging and large amount of
centrifuge sludge as consequence.
When difficulties with filter clogging are experienced, fuel
incompatibility can be tested by ASTM D 2781 method or similar.
02.1.2 Fuel treatment
02.1.2.1 Purification
Heavy fuel (residuals, and mixtures of residuals and distillate)
must be purified in an efficient centrifuge before entering the day
tank. The fuel is to be heated before centrifuging.
Recommended temperatures, depending on the fuel viscosity,
are stated in the diagram, chapter 02, Fig 02-1.
Be sure that the correct gravity disc is used. Never exceed the
flow rates recommended for the centrifuge for the grade of fuel in
use. The lower the flow rate the better the efficiency.
Recommended centrifuge flow rate
Fuel in use
Max. viscosity (cSt/100°C) 10 15 25 35 45 55
Approx. viscosity (cSt/50°C) 50 90 205 350 530 730
Centrifuge flow rate
(% of rated capacity) 60 40 30 25 20 15
For marine diesel oil (max. viscosity 14 cSt at 40°C) a flow rate of
80 % and a temperature of 45°C are recommended.
In case pure distillate fuel is used, centrifuging is still recom-
mended as fuel may be contaminated in the storage tanks.
22-9601 Fuel, Lubricating Oil, Cooling Water 02
VASA 22 02 - 1