WÄRTSILÄ 46DF, Руководство по эксплуатации продукта

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6. Fuel System
6.1 Acceptable fuel characteristics
6.1.1 Gas fuel specification
As a dual fuel engine, the Wärtsilä 46DF engine is designed for continuous operation in gas
operating mode or diesel operating mode. For continuous operation in the rated output, the
gas used as main fuel in gas operating mode has to fulfill the below mentioned quality
requirements.
Table 6-1 Fuel Gas Specifications
Value Unit Property
28 MJ/m
3
N
2)
Lower heating value (LHV), min
1)
80 Methane number (MN), min
3)
70 % volume Methane (CH
4
), min
0.05 % volume Hydrogen sulphide (H
2
S), max
3 % volume Hydrogen (H
2
), max 4)
0,01 mg/m 3 N Oil content, max.
25 mg/m 3 N Ammonia, max
50 mg/m 3 N Ch Fluorines, max
50 mg/m 3 N Particles or solids at engine inlet, max
5
μ
m Particles or solids at engine inlet, max size
0…60 °C Gas inlet temperature
Water and hydrocarbon condensates at engine inlet not allowed
5)
The required gas feed pressure is depending on the LHV (see section Output limitations in gas mode). 1)
Values given in m³
N
are at 0°C and 101.3 kPa. 2)
Given Methane Number limits are valid for charge air temperature of 45 °C (see section Output limitations in gas mode).
Methane Number (MN) can be assigned to any gaseous fuel indicating the percentage by volume of methane in blend with
hydrogen that exactly matches the knock intensity of the unknown gas mixture under specified operating conditions in a knock
testing engine. The Methane Number (MN) gives a scale for evaluation of the resistance to knock of gaseous fuels. 3)
To define the Methane Number (MN) of the gas, the method included in the EN 16726-2015 standard shall be used. Additionally,
Wärtsilä has developed an internal MN calculator. Depending on the gas composition, the MN results obtained with those
two methods can differ from each other, and therefore it is recommended to calculate MN also with the Wärtsilä method. If
the difference of MN for a specific gas quality calculated with the two above mentioned methods is bigger than 3 units,
Wärtsilä has to be contacted for further evaluation.
Further, if the total concentration of the heavier hydrocarbons than butane (C
4
), i.e. pentane (C
5
), hexane (C
6
), heptane (C
7
),
etc. exceeds 1,0 % v/v, Wärtsilä has to be contacted for further evaluation.
Hydrogen content higher than 3% volume has to be considered project specifically. 4)
Dew point of natural gas is below the minimum operating temperature and pressure. 5)
6.1.2 Liquid fuel specification
The fuel specifications are based on the ISO 8217:2017(E) standard. Observe that a few
additional properties not included in the standard are listed in the tables. For maximum fuel
temperature before the engine, see chapter "Technical Data".
The fuel shall not contain any added substances or chemical waste, which jeopardizes the
safety of installations or adversely affects the performance of the engines or is harmful to
personnel or contributes overall to air pollution.
DBAD209883 6-1
6. Fuel System Wärtsilä 46DF Product Guide