Man L23/30DF, Project Manual

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Specification of heavy fuel oil (HFO)
Prerequisites
MAN Diesel & Turbo four-stroke diesel engines can be operated with any
heavy fuel oil obtained from crude oil that also satisfies the requirements in
table The fuel specification and corresponding characteristics for heavy fuel
oil providing the engine and fuel processing system have been designed
accordingly. To ensure that the relationship between the fuel, spare parts
and repair / maintenance costs remains favourable at all times, the following
points should be observed.
Heavy fuel oil (HFO)
The quality of the heavy fuel oil largely depends on the quality of crude oil
and on the refining process used. This is why the properties of heavy fuel oils
with the same viscosity may vary considerably depending on the bunker
positions. Heavy fuel oil is normally a mixture of residual oil and distillates.
The components of the mixture are normally obtained from modern refinery
processes, such as Catcracker or Visbreaker. These processes can
adversely affect the stability of the fuel as well as its ignition and combustion
properties. The processing of the heavy fuel oil and the operating result of
the engine also depend heavily on these factors.
Bunker positions with standardised heavy fuel oil qualities should preferably
be used. If oils need to be purchased from independent dealers, also ensure
that these also comply with the international specifications. The engine oper-
ator is responsible for ensuring that suitable heavy fuel oils are chosen.
Fuels intended for use in an engine must satisfy the specifications to ensure
sufficient quality. The limit values for heavy fuel oils are specified in Table The
fuel specification and corresponding characteristics for heavy fuel oil . The
entries in the last column of this Table provide important background infor-
mation and must therefore be observed
The relevant international specification is ISO 8217 in the respectively appli-
cable version. All qualities in these specifications up to K700 can be used,
provided the fuel system has been designed for these fuels. To use any fuels,
which do not comply with these specifications (e.g. crude oil), consultation
with Technical Service of MAN Diesel & Turbo in Augsburg is required. Heavy
fuel oils with a maximum density of 1,010 kg/m3 may only be used if up-to-
date separators are installed.
Even though the fuel properties specified in the table entitled
The fuel specifi-
cation and corresponding properties for heavy fuel oil satisfy the above
requirements, they probably do not adequately define the ignition and com-
bustion properties and the stability of the fuel. This means that the operating
behaviour of the engine can depend on properties that are not defined in the
specification. This particularly applies to the oil property that causes forma-
tion of deposits in the combustion chamber, injection system, gas ducts and
exhaust gas system. A number of fuels have a tendency towards incompati-
bility with lubricating oil which leads to deposits being formed in the fuel
delivery pump that can block the pumps. It may therefore be necessary to
exclude specific fuels that could cause problems.
The addition of engine oils (old lubricating oil, ULO – used lubricating oil) and
additives that are not manufactured from mineral oils, (coal-tar oil, for exam-
ple), and residual products of chemical or other processes such as solvents
(polymers or chemical waste) is not permitted. Some of the reasons for this
Origin/Refinery process
Specifications
Important
Blends
2017-07-11 - de
Specification of heavy fuel oil (HFO)
D010.000.023-05-0001
General
MAN Diesel & Turbo
010.000.023-05
D010.000.023-05-0001 EN 1 (13)