WÄRTSILÄ PAAE051728, Instruction Manual

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02.1.5 Measures to avoid difficulties when running on
heavy fuel
Poor fuel quality will influence on wear, engine part lifetime and
maintenance intervals adversely.
In order to obtain maximum operating economy it is recommend-
able:
a) to limit maximum continuous output as much as operating condi-
tions allow if fuel is known or suspected to have high vanadium
content (above 200 ppm) and sodium content.
b) to limit low load operation as much as operating conditions al-
low if fuel is known or suspected to have high sulphur content
(above 3 mass-%), carbon content (Conradson carbon above
12 mass-%) and/or asphaltene content (above 8 mass-%).
Operating below 20% of rated output should be limited to max. 100
hours continuously, by loading the engine above 70% of rated load for
one hour before continuing the low load operation or shutting down
the engine.
Idling (i.e. main engine declutched, generator set disconnected)
should be limited as much as possible. Warming-up of the engine
at no load for more than 3 - 5 minutes before loading, as well as
idling for more than 3 minutes before stopping is unnecessary and
should be avoided.
02.1.6 General advice
To avoid stability and incompatibility problems (precipitation of
heavy components in the fuel), avoid, if possible, blending of fuels
from different bunker stations, unless the fuels are known to be
compatible.
If stability and compatibility problems occur, never add distillate
fuel, as this will probably increase precipitation. A fuel additive with
a highly powerful dispersing characteristics can be of help until a
new fuel delivery takes place.
The characteristics of heavy fuels blended from residuals from
modern refinery processes like catalytic cracking and visbreaking
may approach at least some of the limits of fuel characteristics given
in the chapter 02., sect. 02.1.3.
Compared with “traditional” heavy fuels blended from straight
run residuals, the “modern” heavy fuels may have reduced ignition
and combustion quality.
Fuels blended from catalytic cracking residuals may contain very
abrasive catalytic fines (silicon and aluminium oxides) which, if
allowed to enter the injection system, may wear down injection
pumps and nozzles in a few hours.
Some of the difficulties that may occur when operating on heavy
fuels blended from cracked residuals can be avoided by:
·
Sufficient centrifuging capacity. The best and most distur-
bance-free results are obtained with the purifier and clarifier
200549-01 Fuel, Lubricating Oil, Cooling Water
W20/W32/W46, W46F, 32, 32LN 02 - 11