Power Plants

Liquid fuels

Depending on power plant solution Wärtsilä engines are able to run on a wide selection of fuels, ranging from Light fuel oil to fuel-water-emulsions.

Fuels such as crude oil, fuel-water-emulsions and other fuels outside globally recognized standard fuel specifications, should be carefully analysed for each power plant project prior to use.

LIGHT FUEL OIL

Light fuel oils or diesel oils are high value distillates and have traditionally been the fuels for diesel engines power plants both for standby operation and baseload applications. The use of light fuel oils in baseload applications has decreased since it has become possible to use cheaper lower grade fuels. There are however still applications such as backup power plants, islands and installations in arctic conditions where light fuel oil is the preferred alternative.

The fuel specification is based on the ISO 8217:2010(E) standard and covers the fuel categories ISO-F-DMA → DMB.

Property
 Unit
DMA
DMZ
DMB
Test method
reference
Kinematic viscosity at 40°C, min.i)
Kinematic viscosity at 40°C, max.
mm²/s a)
mm²/s a)
2.000
6.000
 3.000
 6.000
 2.000
 11.00
 ISO 3104
Density at 15°C, max.
kg/m³
 890.0
 890.0
 900.0
ISO 3675 or
ISO 12185
Cetane index, min.
- 
 40
 40
 35
ISO 4264 
Sulphur, max. b)
% m/m
1.50 
 1.50
 2.00
ISO 8754 or
ISO 14596
Flash point, min.
°C
 60.0
 60.0
 60.0
ISO 2719
Hydrogen sulfide, max. c)
mg/kg
2.00
2.00 
2.00
IP 570
Acid number, max.
mg KOH/g
0.5
0.5 
0.5 
ASTM D664
Total sediment by hot filtration
(Total sediment existent), max.
% m/m
-
 
0.10 e)
ISO 10307-1
Oxidation stability, max.
g/m³
25
25
25 f)
ISO 12205
Carbon residue on 10 % v/v distillation bottoms, max.
Carbon residue: micro method, max. 
% m/m   
 0.30
 
-
 0.30
 
-
 -
 
0.30 
ISO 10370
 
ISO 10370
Pour point (upper), max. d)
-Winter quality
-Summer quality
 
°C
 
 
-6
0
 
-6
0
 
0
6
 
ISO 3016
 
Appearance
-
 Clear and bright  j)
e, f, g)
-
Water, max.
% v/v
-
 
0.30 e) 
ISO 3733
Ash, max.
 % m/m
0.010
0.010
0.010
ISO 6245
Lubricity, corrected to wear scar diameter (wsd 1,4) at 60°C, max h)
 µm
 
520 
 
 520
 
 520 g)
 
 ISO 12156-1
 
a) 1 mm²/s = 1 cSt
b) Notwithstanding the limits given, the purchaser shall define the maximum sulphur content in accordance with relevant statutory limitations.
c) The implementation date for compliance with the limit shall be 1 July 2012. Until such time, the specified value is given for guidance.
d) Purchasers shall ensure that this pour point value is suitable for the equipment on board / at the plant, especially if the ship operates / plant is located in cold climates.
e) If the sample is not clear and bright, the total sediment and water tests shall be required.
f)  If the sample is not clear and bright, the test cannot be undertaken and hence the oxidation stability limit shall not apply.
g) If the sample is not clear and bright, the test cannot be undertaken and hence the lubricity limit shall not apply.
h) The requirement is applicable to fuels with sulphur content below 500 mg/kg (0,050 m/m).
i) Additional properties specified by the engine manufacturer, which are not included in the ISO 8217:2010(E) standard:
  • Min. injection viscosities: W 20:1,8, W 26, W 32, W 38, W 46CR, W 46 F: 2,0 and W 46 (with conv. FIE), W 64: 2,8 mm²/s, W 32DF, W 34DF: 2.0 mm²/s for pilot and main / back-up fuel, W 50DF: 2.0 mm²/s for pilot fuel and 2,8 mm2/s for main / back-up fuel, for all 2-stroke engine types. 2,0 mm²/s.
  • Max. injection viscosity for all am. 4-stroke diesel engine types 24 mm²/s, for DF engines 11,0 mm²/s for pilot fuel and 24,0 mm²/s for main / back-up fuel, for all 2-stroke engines 17,0 mm²/s.
j) If the sample is dyed and not transparent, then the water limit and test method ISO 12937 shall apply.
 
The fuel shall not contain any additive at the concentration used in the fuel, or any added substance or chemical waste that jeopardizes the safety of installation or adversely affects the performance of the machinery or is harmful to personnel or contributes overall to additional air pollution.  
 

HEAVY FUEL OIL

Heavy fuel oils are blended products based on the residues from various refinery distillation and cracking processes. They are black viscous liquids which require heating for storage and combustion. Heavy fuel oils are used for diesel engines mainly in base load power plants.

The fuel specification “HFO 2” is based on the ISO 8217:2005(E) standard and covers the fuel categories ISO-F-RMA 30 – RMK 700. Additionally, the engine manufacturer has specified the fuel specification “HFO 1”. This tighter specification is an alternative and by using a fuel fulfilling this specification, longer overhaul intervals of specific engine components may be expected (see the Engine Manual of a specific engine type).

Property
 Unit
Limit
HFO 1
Limit
HFO 2
Test method
reference
Viscosity
at 50 / 100°C, max.
at 100°F, max.
 
cSt
Redwood No. 1 sec.  
 
700 / 55
7200
 
700 / 55
7200 
 
ISO 3104
Viscosity before injection
pumps 4)
 
cSt
 
20±4
 
20±4
 
 
Density at 15°C, max.
kg/m³
991.0/
1010.0 1)
991.0/
1010.0 1)
ISO 3675 or
12185
CCAI, max. 4)
 
850
870 2)
ISO 8217, Annex B   
Water, max.
Vol-%
0.5
0.5
ISO 3733
Water before engine, max. 4) Vol-% 0.3 0.3 ISO 3733
Sulphur, max.
% m/m
1.50 
4.50 5)
ISO 8754 or
14596
Ash, max.
% m/m
 0.05
 0.15
ISO 6245
Vanadium, max. 3)
mg/kg
100
600
ISO 14597 or
IP 501 or 470
Sodium, max. 3) 4) mg/kg 50 50 ISO 10478
Sodium before engine, max. 3) 4)
mg/kg
30
30
ISO 10478
Aluminium + Silicon,
max.
mg/kg
30
80
ISO 10478 or
IP 501 or 470
Aluminium + Silicon
before engine, max. 4)
mg/kg
15
15
ISO 10478 or
IP 501 or 470
Carbon residue, max. 
% m/m   
 15
22
ISO 10370 
Asphaltenes, max. 4) % m/m 8 14 ASTM D 3279
Flash point (PMCC), min.
°C
60
 60
ISO 2719
Pour point, max.
°C
30
30 
ISO 3016
Total sediment potential,
max.
% m/m
0.10
0.10 
ISO 10307-2
Used lubricating oil 6) 
-Calcium, max.
-Zinc, max.
-Phosphorus, max.
 
mg/kg
mg/kg
mg/kg
 
30
15
15
 
30
15
15
 
IP 501 or 470
IP 501 or 470
IP 501 or 500
1) Max. 1010 kg/m³ at 15°C, provided the fuel treatment system is designed accordingly.
2) Straight run residues show CCAI values in the 770 to 840 range and are very good ignitors. 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.
3) Sodium contributes to hot corrosion on 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, but 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.
4) Additional properties specified by the engine manufacturer, which are not included in the ISO specification.
5) Following sulphur limits of the liquid fuel content or equivalent SO2-levels will apply in Non-Degraded Airsheds (NDA) for reciprocating engine plants according to the “Thermal Power Plants EHS Guidelines” issued by International Finance Corporation (IFC) in 2008:
  • 50 .. 300 MWth: maximum 2% m/m S
  • >300 MWth: maximum 1% m/m
For smaller plants there are other limits. There may also be other national/local variations.

6) A fuel shall be considered to be free of used lubricating oil (ULO), if one or more of the elements calcium, zinc and phosphorus are below or at the specified limits. All three elements shall exceed the same limits before a fuel shall be deemed to contain ULO. 
  

CRUDE OIL

Crude oil is a highly complex mixture of hydrocarbons and other components. The flash point of crude oil is low, typically below ambient temperature. Crude oil can also be used as fuel in power plants with diesel engines, for example for power production in the oil field. Another application is pumping stations along a crude pipe line where fuel from the pipe line can be used for the prime movers.

Property
 Unit
Limit
Test method reference
Viscosity, min., before injection pumps
max. before injection pumps
cSt
2.8
24
 
Viscosity at 50 / 100°C, max.
at 100°F, max.
cSt
Redwood No. 1 sec.  
700 / 55
7200
ISO 3104
 
Density at 15°C, max.
kg/m³
991.0/
1010.0 1)
ISO 3675 or 12185
CCAI, max.
 
870
ISO 8217
Water before engine, max. Vol-% 0.3 ISO 3733
Sulphur, max.
% m/m
4.50 
ISO 8754 or 14596
Ash, max.
% m/m
0.15
ISO 6245
Vanadium, max.
mg/kg
600
ISO 14597 or IP 501 or 470
Sodium, max. mg/kg
50
 ISO 10478
Sodium before engine, max.
mg/kg
30
ISO 10478
Aluminium + Silicon, max.
mg/kg
30
ISO 10478 or IP 501 or 470
Aluminium + Silicon
before engine, max.
mg/kg
15
ISO 10478 or IP 501 or 470
Calcium + Potassium +
Magnesium before engine, max.
 mg/kg
50
IP 501 or 500 for Ca and
ISO 10478 for K and Mg
Carbon residue, max. 
% m/m   
22
ISO 10370 
Asphaltenes, max. % m/m
14
 ASTM D 3279
Reid vapour pressure, max. at 37.8°C kPa
65
 ASTM D 323
Pour point, max.
°C
30
ISO 3016
Cloud point or
Cold filter plugging point, max.
°C
60 2)
ISO 3015
IP 309
Total sediment potential,
max.
% m/m
0.10
ISO 10307-2
Hydrogen sulphide, max.
mg/kg
5
IP399

1) Max. 1010 kg/m³ at 15°C, provided the fuel treatment system is designed accordingly.
2) Fuel temperature in the whole fuel system including storage tanks must be kept during  standby, start-up and operation 10–15°C above the cloud point in order to avoid crystallization and formation of solid waxy compounds (typically paraffins) causing blocking of fuel filters and small size orifices. Additionally, fuel viscosity sets a limit to cloud point so that fuel must not be heated above the temperature resulting in a lower viscosity before the injection pumps than specified above.

Read more about Wärtsilä oil power plants.

 

LIQUID BIOFUEL

Liquid biofuels are derived from biological material and can be produced from a variety of carbon sources. Common liquid biofuels approved for use in Wärtsilä engines are oils from various oilseeds, such as palm oil, palm stearin, rape seed oil, sunflower oil and jatropha oil. Liquid biofuels can also be of non vegetable origin, i.e. oils or fats from fish, poultry and animals. Refined biofuel qualities such as transesterified biodiesel or hydrogenated renewable diesel can of course also be used.
 

Features:

  • Crude LBF can be used instead of transesterified biodiesel or hydrogenated renewable diesel, giving also much better energy balance.
  • Using bottom residuals (FWE ) enables the use of high quality light fractions in more demanding applications.
  • Using Crude Oil in oil field applications (power generation and pumping) it is not necessary to transport expensive diesel oil for same purposes.
  • The transportation of liquid fuels is relatively safe and efficient.
  • The energy density of liquid fuel is high comparing to other fuels.

 

Property
 Unit
Limit
Test method reference
Viscosity, max.
Injection viscosity, min.
Injection viscosity, max.
cSt @40°C
cSt
cSt
100 1)
1.8-2.8 2)
24
 ISO 3104
Density, max.
kg/m³ @15°C
991
ISO 3675 or 12185
Ignition properties 3)
 
  
FIA test
Sulphur, max.
% m/m
 0.05
ISO 8754
Total sediment existent, max. % m/m 0.05 ISO 10307-1
Water. max. before engine Vol-%
0.20
ISO 3733
Micro carbon residue, max. % m/m 0.50 ISO 10370
Ash, max.
% m/m
0.05
ISO 6245 / LP1001
Phosphorus, max.
mg/kg
100
ISO 10478
Silicon, max. mg/kg
15
 ISO 10478
Alcali content (Na + K), max.
mg/kg
30
ISO 10478
Flash point (PMCC), min.
°C
60
ISO 2719
Cloud point, max.
°C
4)
ISO 3015
Cold filter plugging point, max.
 °C 4) IP 309
Copper strip corrosion (3 hrs @ 50°C), max.
Rating  
1b
ASTM D130
Steel corrosion (24 / 72 hours @ 20, 60 and 120°C), max. Rating
No signs of corrosion
 LP 2902
Acid number, max. mg KOH/g
15.0
 ASTM D664
Strong acid number, max.
mg KOH/g
0.0
ASTM D664
Iodine number, max.
g iodine / 100 g
120
ISO 3961
Synthetic polymers
% m/m
Report 5)
LP 2401 ext. and LP 3402
1) If injection viscosity of max. 24 cSt can not be achieved with an unheated fuel, fuel system has to be  equipped with a heater.
2) Min. limit at engine inlet in running conditions; Wärtsilä 20: 1.8 cSt, Wärtsilä 32: 2.0 cSt, Wärtsilä  46:2.8 cSt, Wärtsilä 34DF: 2.0 cSt, Wärtsilä 50DF: 2.8 cSt.
3) Ignition properties have to be equal to or better than the requirements for fossil fuels, i.e., CN min. 35  for LFO and CCAI max. 870 for HFO.
4) Cloud point and cold filter plugging point have to be at least 10°C below fuel injection temperature.
5) Biofuels originating from food industry can contain synthetic polymers, like e.g. styrene, propene and  ethylene used in packing material. Such compounds can cause filter clogging and shall thus not be present in biofuels.

 

BIODIESEL

 

Property
 Unit
Limit
Test method reference
Viscosity, min. - max.
Injection viscosity, min.
cSt @40°C
cSt
3.50-5.00
1.8-2.81)   
EN ISO 3104
 
Density, min - max.
kg/m³ @15°C 
860-900   
EN ISO 3675 / 12185
Cetane number, min.
 
51.0 
EN ISO 5165
Sulphur content, max.
mg/kg
10.0
prEN ISO 20846 / 20884
Sulphated ash content
 % m/m
0.02
ISO 3987
Total contamination,max
 mg/kg
24
EN 12662
Water content, max.
 mg/kg
500
EN ISO 12937
Carbon residue (on 10% distillation residue), max. 
% m/m
0.30
EN ISO 10370
Phosphorus content, max.
mg/kg
10.0
EN 14107
Group I metals (Na + K) content, max.
 mg/kg
5.0
EN 14108 / 14109
Group II metals (Ca + Mg) content, max.
mg/kg
5.0
prEN 14538
Flash point, min.
°C
120
prEN ISO 3679
Cold filter plugging point, max.
(climate dependent requirement)
°C
-44 → +5  2)
EN 116
Oxidation stability @ 110°C, min.
 hrs
6.0
EN 14112
Copper strip corrosion (3 hrs @ 50°C), max.
Rating  
Class 1
EN ISO 2160
Acid value, max.
 mg KOH/g
0.50
EN 14104
Iodine value, max.
g iodine / 100 g
120
EN 14111
Ester content, min.
 % m/m
96.5
EN 14103
Linolenic acid methyl ester, max.
 % m/m
12.0
EN 14103
Polyunsaturated methyl esters, max.
 % m/m
1 
 
Methanol content, max.
 % m/m
0.20
EN 14110
Monoglyceride content, max.
 % m/m
0.80
EN 14105
Diglyceride content, max.
 % m/m
0.20
EN 14105
Triglyceride content, max.
 % m/m
0.20
EN 14105
Free glycerol, max. 
 % m/m
0.02
EN 14105 / 14106
Total glycerol, max. 
 % m/m
0.25
EN 14105
1) Min. limit at engine inlet in running conditions; Wärtsilä 20: 1.8 cSt, Wärtsilä 32: 2.0 cSt, Wärtsilä 46: 2.8 cSt, Wärtsilä 34DF: 2.0 cSt, Wärtsilä 50DF: 2.0 cSt for pilot fuel & 2.8 cSt for main / backup fuel.
2) Cold flow properties of renewable bio diesel can vary based on the geographical location and also based on the feedstock properties, which issues must be taken into account when designing the fuel system.

 

Read more about Wärtsilä liquid biofuel power plants.

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