Wartsila 31 Product Manual page 47

Wärtsilä 31 Product Guide
6.1.2 Heavy Fuel Oil (HFO)
Residual fuel grades are referred to as HFO (Heavy Fuel Oil). The fuel specification HFO 2
covers the categories ISO-F-RMA 10 to RMK 700. Fuels fulfilling the specification HFO 1
permit longer overhaul intervals of specific engine components than HFO 2.
Table 6-2
Property
Viscosity, before injection pumps
Viscosity at 50°C, max.
Density at 15°C, max.
CCAI, max.
Sulphur, max.
Flash point, min.
Hydrogen sulfide, max.
Acid number, max.
Total sediment aged, max.
Carbon residue, micro method, max.
Asphaltenes, max.
Pour point (upper), max.
Water, max.
Water before engine, max.
Ash, max.
Vanadium, max.
Sodium, max.
Sodium before engine, max.
Aluminium + Silicon, max.
Aluminium + Silicon before engine, max.
Used lubricating oil, calcium, max.
Used lubricating oil, zinc, max.
Used lubricating oil, phosphorus, max.
Remarks:
1)
2)
3)
4)
5)
6)
7)
Wärtsilä 31 Product Guide - a1 - 18 October 2016
HFO specifications
1)
3)
4) 5)
6)
1)
7)
1)
5)
5)
1) 5)
8)
8)
8)
Additional properties specified by Wärtsilä, which are not included in the ISO specification.
Max. 1010 kg/m³ at 15°C provided that the fuel treatment system can remove water and solids (sediment, sodium, aluminium,
silicon) before the engine to specified levels.
Straight run residues show CCAI values in the 770 to 840 range and have very good ignition quality. Cracked residues delivered
as bunkers may range from 840 to - in exceptional cases - above 900. Most bunkers remain in the max. 850 to 870 range at
the moment. CCAI value cannot always be considered as an accurate tool to determine the ignition properties of the fuel,
especially concerning fuels originating from modern and more complex refinery process.
The max. sulphur content must be defined in accordance with relevant statutory limitations.
Sodium contributes to hot corrosion on the exhaust valves when combined with high sulphur and vanadium contents. Sodium
also strongly contributes to fouling of the exhaust gas turbine blading at high loads. The aggressiveness of the fuel depends
on its proportions of sodium and vanadium and also on the total amount of ash. Hot corrosion and deposit formation are,
however, also influenced by other ash constituents. It is therefore difficult to set strict limits based only on the sodium and
vanadium content of the fuel. Also a fuel with lower sodium and vanadium contents than specified above, can cause hot
corrosion on engine components.
The implementation date for compliance with the limit shall be 1 July 2012. Until that, the specified value is given for guidance.
It shall be ensured that the pour point is suitable for the equipment on board, especially if the ship operates in cold climates.
Unit
cSt
cSt
kg/m³
% mass
°C
mg/kg
mg KOH/g
% mass
% mass
% mass
°C
% volume
% volume
% mass
mg/kg
mg/kg
mg/kg
mg/kg
1) mg/kg
mg/kg
mg/kg
mg/kg
6. Fuel Oil System
Limit HFO 1 Limit HFO 2
16...24 16...24
700 700
991 / 1010 2) 991 / 1010 2)
850 870
Statutory requirements
60 60
2 2
2.5 2.5
0.1 0.1
15 20
8 14
30 30
0.5 0.5
0.3 0.3
0.05 0.15 ISO 6245 or LP1001
100 450
50 100
30 30
30 60
15 15
30 30
15 15
15 15
Test method ref.
ISO 3104
ISO 3675 or 12185
ISO 8217, Annex F
ISO 8754 or 14596
ISO 2719
IP 570
ASTM D664
ISO 10307-2
ISO 10370
ASTM D 3279
ISO 3016
ISO 3733 or ASTM
D6304-C 1)
ISO 3733 or ASTM
1)
D6304-C
1)
ISO 14597 or IP 501
or IP 470
IP 501 or IP 470
IP 501 or IP 470
ISO 10478 or IP 501
or IP 470
ISO 10478 or IP 501
or IP 470
IP 501 or IP 470
IP 501 or IP 470
IP 501 or IP 500
6-3