Wärtsilä gaseous fuels
Depending on power plant solution Wärtsilä engines are able to run on a wide selection of fuels, ranging from natural gas to associated gas.
Fuels such as associated gas, biogas and other fuels outside globally recognized standard fuel specifications, should be carefully analyzed for each power plant project prior to use.
Natural gas
Natural gas of commercial pipeline quality. These gases consist mainly of methane and are processed to meet guaranteed specifications for heating value, Wobbe index and cleanliness.
Wärtsilä gas engines are designed and developed for continuous operation on natural gas, without reduction in the rated output, on gas qualities according to the specification below. Other gases than pipeline quality natural gas can also be used and are considered on a case by case basis.
|
Property
|
Unit
|
Limit
|
|||
|---|---|---|---|---|---|
| Lower heating value (LHV), min. | MJ/m³N 2) |
28 1)
|
|||
|
Methane number (MN), min.
|
|
80 3)
|
|||
|
Methane (CH4) content, min. 4)
|
Vol-%
|
70
|
|||
|
Hydrogen sulphide (H2S) content, max .
|
Vol-%
|
0.05
|
|||
|
Hydrogen (H2) content, max. 4)
|
Vol-%
|
3.0
|
|||
|
Water and hydrocarbon condensate before engine, max. 5)
|
Vol-%
|
Not allowed
|
|||
|
Ammonia content, max.
|
mg/m³N
|
25
|
|||
|
Chlorine + Fluorine content, max.
|
mg/m³N
|
50
|
|||
|
Particles or solids content in engine inlet, max.
|
mg/m³N
|
50
|
|||
|
Particles or solids size in engine inlet, max.
|
µm
|
5
|
|||
|
Gas inlet temperature
|
°C
|
0-60
|
|||
|
1) The required gas feed pressure is depending on the LHV, e.g. for SG and DF engines 28 MJ/m³N requires 6 bar a pressure for full engine output. In GD engines low LHV can be compensated with fuel sharing.
2) Values for volume (m³N) are given at 0°C and 101.3 kPa. 3) SG and DF engine outputs is depending on the Methane Number. Full engine output at highest efficiency is achieved at MN80, lower MN can be used with an influence on engine performance and may cause derating of the engine. GD engines are not affected by MN. Methane Number (MN) can be assigned to any gaseous fuel based on its composition and it gives a scale to compare the resistance to knock of different gases. The MN is calculated by Wärtsilä. 4) If the hydrogen content of gas is higher than 3.0 vol-%, or the methane content is lower than 70 vol-%the use of gas has to be considered case by case. 5) Dew point of natural gas is below the minimum operating temperature and pressure. |
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Associated gas
Associated gas is a constituent that is separated from crude oil in the degassing equipment at the oil fields. The methane content is less than in natural gas, but the concentration of heavier hydrocarbons is higher, thus normally producing a high heating value. Gas-diesel (GD) engines are very suitable for burning associated gas, either in normal gas-diesel mode or using the “fuel sharing” mode.
Bio gases
Bio gases are the result of treating biological matter in digesters or through other decomposing processes. The resulting gas consists of methane and carbon dioxide.
Coal bed natural gas
Coal bed natural gas is gas that is collected from underground coal layers. It contains methane, water and carbon dioxide in varying concentrations.
Read more about Wärtsilä gas power plants .