Marine Propulsion Applications, Gas Fuel Gas Specification
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1.05
0315 B/P
FUEL GAS SPECIFICATION
General
The fuel gas composition shall be made available for
the engine manufacturer prior to any contract can be
signed. The composition given must be from a
representative sample and a typical result of several
samples over a given period of time. If it is known,
or is possible, that in the course of time greater
variations in this composition can occur, this must be
referred to specifically.
The engine is fully suitable only for the specific fuel
gas it has been sold for.
Because engine equipment and engine adjustments
are optimized only for the gas it has been sold for, it
must be guaranteed that the methane content will
not fall below the minimal values given in the
technical specifications for a given installation. In the
latter case, the matter must be cleared with the
respective gas utility and representative of RR.
Depending on the fuel gas composition, the correct
lube oil type shall be chosen, and in case of
bio gases, regular analyses shall be made of the gas
and compared with the lube oil recommendations.
Required characteristics of the fuel gas
supply at gas pressure regulating
module inlet:
• Fluctuation in the gas pressure less than 0,5 bar/
30 sec. is not critical, assuming that we still are
above the minimum pressure.
• Max. permissible heat value fluctuations:
0.5%/10 minutes.
• Min. Lower Calorific Value of the fuel gas:
..........26 MJ/Nm
3
• Required static fuel gas pressure:
- natural gas (36 MJ/Nm
3
):
Please see technical data, chapter 1.02
• Min. methane number: ..........................................70
Fuel gas quality
Clean and dry gas, without any free droplets of
moisture and solid particles.
General requirement:
- temperature range: .....................................25 - 40 °C
- temperature target: ............................................. 30 °C
- condensate: .................................................................... 0
- dust: max. particle size: ...............................5 micron
max. content: ................................. 50 mg/Nm
3
- max. content of sulphuric compounds,
calculated as H
2
S: ............................................. 50 ppm
(approx. = 0,005% vol.) ............................ 76 mg/Nm
3
Reference conditions for the volume designation -
Nm
3
:
Atmospheric pressure: .................................. 1,013 bar
Temperature: .............................................................. 0 °C
Gas samples:
In order to avoid operational problems like
corrosion, wear, lube oil contamination etc. it is
required to take gas samples at regular intervals and
have them analysed with respect to corrosive trace
gases like H
2
S, chlorides, halogens etc.
The following sampling frequencies are
recommended:
- Weekly during the first three weeks of operation.
- Every three weeks for the next three months,
thereafter every six weeks.
The samples should be taken and analysed by
qualified laboratories and the results made known
as quickly as possible to the RR Service Dept.,
at least for the guarantee period of the engine.
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