Man L23/30DF, Project Manual

Page: 117 / 392

General
Exhaust emissions from marine diesel engines have
been the focus of recent legislation. Apart from
nitrous oxides (NOx), sulphur oxides (SOx) are con-
sidered to be the most important pollution factor. A
range of new regulations have been implemented
and others will follow (IMO, EU Directive, and
CARB). These regulations demand reduction of
SOx emissions by restricting the sulphur content of
the fuel. That is to say sulphur limits for HFO as well
as mandatory use of low sulphur distillate fuels for
particular applications. This guideline covers the
engine related aspects of the use of such fuels.
Low sulphur HFO
From an engine manufacturer’s point of view there
is no lower limit for the sulphur content of HFO. We
have not experienced any trouble with the currently
available low sulphur HFO, that are related to the
sulphur content or specific to low sulphur HFO. This
may change in the future if new methods are
applied for the production of low sulphur HFO
(desulphurization, uncommon blending compo-
nents). MAN Diesel & Turbo will monitor develop-
ments and inform our customers if necessary.
If the engine is not operated permanently on low
sulphur HFO, then the lubricating oil should be
selected according to the highest sulphur content
of the fuels in operation.
Low sulphur distillates
In general our GenSet is developed for continuous
operation on HFO as well as on MDO/MGO. Occa-
sionally changes in operation mode between HFO
and MDO/MGO are considered to be within normal
operation procedures for our engine types and do
thus not require special precautions.
Running on low sulphur fuel (< 0.1% S) will not
cause problems, but please notice the following
restrictions:
In order to avoid seizure of the fuel oil injection
pump components the viscosity at engine fuel oil
inlet must be > 2 cSt. In order achieve this it may be
necessary to install a fuel oil cooler, when the
engine is running on MGO. This is both to ensure
correct viscosity and avoid heating up the service
tank, which is important as the fuel oil injection
pumps are cooled by the fuel.
When operating on MDO/MGO a larger leak oil
amount from fuel oil injection pumps and fuel oil
injection valves can be expected compared to oper-
ation on HFO.
In order to carry out a quick change between HFO
and MDO/MGO the change over should be carried
out by means of the valve V1-V2 installed in front of
the engine.
For the selection of the lubricating oil the same
applies as for HFO. For temporary operation on dis-
tillate fuels including low sulphur distillates nothing
has to be considered. A lubricating oil suitable for
operation on diesel fuel should only be selected if a
distillate fuel is used continuously.
MAN Diesel & Turbo
1699177-5.1
Page 1 (1)
Guidelines regarding MAN Diesel & Turbo GenSets
operating on low sulphur fuel oil
B 11 00 0
L23/30DF, L28/32S, L27/38S, L23/30S, L21/31S, L16/24S, V28/32S-DF, L28/32DF,
V28/32H, V28/32S, L16/24, L21/31, L23/30H, L27/38, L28/32H
2015.11.27