6.
Fuel System
6.1
Acceptable fuel characteristics
6.1.1
Gas fuel specification
As a dual fuel engine, the Wärtsilä 50DF engine is designed for continuous operation in gas
operating mode or diesel operating mode. For continuous operation without reduction 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 (IMO Tier 2)
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)
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
um
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)
The methane number (MN) of the gas is to be defined by using AVL’s “Methane 3.20” software. The MN is a calculated value
that gives a scale for evaluation of the resistance to knock of gaseous fuels. Above table is valid for a low MN optimized engine.
Minimum value is depending on engine configuration, which will affect the performance data.
However, if the total content of hydrocarbons C5 and heavier is more than 1% volume Wärtsilä has to be contacted for further
evaluation.
3)
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 8217:2012 (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.
Marine Diesel Fuel (MDF)
Distillate fuel grades are ISO-F-DMX, DMA, DMZ, DMB. These fuel grades are referred to as
MDF (Marine Diesel Fuel).
Wärtsilä 50DF Product Guide - a16 - 9 September 2016
6-1
6. Fuel System
Wärtsilä 50DF Product Guide
Summary of Contents for WARTSILA 50DF
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