workshop on alternative marine fuels “engg e tec ca adjust e...
TRANSCRIPT
Workshop on alternative marine fuels
“Engine technical adjustment” g e tec ca adjust e tLENNART HARALDSON
2010 11 162010.11.16
Rev. 1Rev. 1
Content
1. Gas engines • Combustion influence• Fuel handlingg
2. Low viscosity distillate fuels• Fuel pump behaviourFuel pump behaviour• Performance influence • Fuel incompatibility
3. Bio oils• Approved bio oils
Bi il bi di l• Bio oils vs.bio diesel• Fuel preparation• Fuel characteristics
The driver: new regulations
NOx SOxTier II (2011)Tier III (2016)
Global 3.5% (2012)ECA 0.1% (2015)
Global 0.5%S (2020 or 2025)
COCO2GHG
Under evaluation by IMO
Fuel alternatives in close future
What to choose ?
HFO LFO GASAftertreatment:
ScrubbersSCR
NOx Tier 3compliant engine
+ Low sulphur fuel
Gas as fuel
p
And in the end it all boils down to $$$
Wärtsilä gas engines
1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011
W34DF
W50DF
W20V34SG
W34DF
W220SG
W180SG
W34SG
W28SG
W32DF
W46GD
W25SG
W34SG
GD = Gas Diesel engine
W32GD
gSG = Spark Ignited Gas engineDF = Dual Fuel engine
Gas engine characteristics
Gas-Diesel Duel-Fuel Spark-Ignited
Di l C b ti Ott C b ti Ott C b tiDiesel Combustion(Diffusion Combustion)
+ Not knock sensitive,
Otto Combustion(Premixed Combustion)
+ Tier III (NOx) solution
Otto Combustion(Premixed Combustion)
+ Tier III (NOx) solution,fuel MN not an issue
+ Low THC, CO+ High load acceptance
Tier III (NOx) solution+ Higher ignition energy
than spark plug+ High efficiency (in gas mode)
( )+ No additional fuel
beside gas+ High efficiency
- No Tier III (NOx) solution as is
- Fuel sensitive (knocking), MN>70 no derating
- High THC, CO
- Fuel sensitive (knocking), MN>70 no derating
- High THC, COg- Lower load acceptance
g- Lower load acceptance
Gas consumption
By operating the DF-engine according to propeller curve SFOC and emission reductions will be improved.
Constant Speed Engines Variable Speed Engines
[kJ/
kWh
kJ/k
Wh] Spee
BS
EC
[
BSEC
[k
ed [rpm]
50 75 85 100
BSEC total 6L 9L engines
50 75 85 100
BSEC total 6L 9L engines
Wärtsilä 34DF Wärtsilä 34DF
BSEC total. 6L, 9L engines
BSEC total. 12V, 16V engines
BSEC total. 6L, 9L enginesBSEC total. 12V, 16V enginesSpeed
Wärtsilä 34DF
LNGPac - a solution for LNG fuelled ships
3
1 Storage tanks 6
3
41. Storage tanks
2. Evaporators5
16
3 B k t ti 253. Bunker station
4. Gas valve unit enclosure
2
5. Dual-Fuel Main engine
6. Dual-Fuel Aux engines
Low Sulphur distillate fuels
The use of low sulphur fuel is a primary method t d th SOto reduce the SOx emissions in diesel enginesengines.
Low sulphur heavy fuel p yoils have been in use for some time and the use is
ll d t dwell documented.
If fuels with very lowIf fuels with very low sulphur levels are supplied these are likely pp yto be distillate fuels.
Low viscosity distillate fuel operation
Low flash point:Safety Aspect, Insurance companies can refuse to paycompensation for the damages, e.g. if a fire in an engineroom occurs and a fuel with the flash point of < 60 °Croom occurs and a fuel with the flash point of 60 Chas been used.
Low viscosity:Specified fuel injection viscosities for our engines are:Sulzer 2-s engines: 13 – 17 cStWärtsilä 4-s engines: 16 – 24 cStLS di till t f l t i l 2 St/ 40°CLS distillate fuels typical ~2 cSt/ 40°C
Leakage in the injection system will influence performance !
Compatibility:
Risk of incompatibility of HFO and LFOSpot test - ASTM D 4740 - 95
4
5
HighCompatibility problems are related to the fuel’s stability
2
3
4
Spo
t rat
ing
Moderate
Compatibility problems are related to the fuel s stability reserve. HFOs are rather aromatic and contain asphaltenes.If the stability reserve of such a HFO is low, it cannot stand mixing more paraffinic LFO into it, and as a consequence asphaltenes will precipitate out of the blend.
10 10 20 30 40 50 60 70 80 90 100
% LFO
Low
Source: Fortum
asphaltenes will precipitate out of the blend.
Too low injection viscosity – consequences
Injection equipment Cavitations, wear, seizure. Gas pocket formation in fuel system is also possible consequence.
Engine performance, minor effects
Leakage delay in dynamic injection & prolonged injection period slower heat release reduced cylinder g y y j p g j p ypressure & higher exhaust temperature –> increase in fuel consumption as well as incomplete combustion (increased smoke !!!)
Engine performance, worst case
Vaporisation of lighter fuel fractions, loss of capability to produce full power, stalling, black-out, starting problems fuel leakage into cam boxproblems, fuel leakage into cam box.(Higher risks when pumps are worn)
C bi ti ith l d it f th LS di till t f l i th i kCombination with low density of the LS distillate fuel increase the risk for performance effects !
LS adaption unit
E i t t k it i t l i it f lEquipment to make it easier to run on low viscosity fuels can be obtained as:
Fuel coolers & Fuel chillers to cool down fuel for increase fuel viscosity
Fuel switch equipment to support the switch between HFO & LFO(2°C/ i )(2°C/min.)
Fuel incompatibility
When two different fuels are mixed there is a risk for incompatibilityWhen two different fuels are mixed there is a risk for incompatibility….which may cause
clogging of fuel filtersi d l d tincreased sludge amountsticking of fuel injection pumpsdeposit formation on the engine components
The risk is generally not very high, but incompatibility may occur if two fuels originate fromdifferent crude oils or different refining processes.
I tibilit bl l d i t d t t h bl di f lIncompatibility problems can also occur during steady-state, e.g. when blending fuels.
Mitigationgas much as possible avoid mixing two different fuelsperform a compatibility test onboard before mixing the fuels in questionschedule permitting, make a compatibility test in a laboratory before mixing the fuels in
tiquestion.the size of tanks where different fuels are mixed and duration of the mixing should be minimized. (this requirement is not compatible with the target of minimizing thermal shocks at 2°C/min.))
Liquid Biofuels (LBF)
What are liquid biofuels?
– Liquid biofuels are fuels derived from renewable sources• Vegetable oils/plant oils and their derivatives • Non vegetable oils and fats• Non-vegetable oils and fats • Other liquid fuels derived from renewable raw
material– Wood pyrolysis oilpy y– Bioethanol etc.
– Liquid biofuels are not automatically biodiesel• Biodiesel is defined as non-petroleum-based diesel
fuel consisting of short chain alkyl (methyl or ethyl) esters, made through transesterification of vegetable oil or animal fat ege ab e o o a a a– Other names: FAME, RME, SME etc.
World Production of Oils and Fats 2008
World Production of Oils & Fats 2008160 million tonnes
Palm Oil27%Other
Animal Fats15%
• 2008 Total world production 160 million tonnes (Jatropha oil not
S b OilRapeseed Oil
12%
Vegetable Oils13% Palm Kernel
Oil3%
( pincluded)
• 2008 Total world consumption of mineral crude oil 3927.9 million
Soyabean Oil23%
12%Sunflower Oil
7%tonnes (BP)
Source : Oil World Annual (1999 - 2007) & Oil World Weekly (14 December, 2007).Source : MPOB - For data on Malaysian palm oil and palm kernel oil.Source : BP Statistical Review of World Energy
Wärtsilä LBF Status
Approved Liquid Bio fuels:pp q
All vegetable based oils as well as animal fats as long as they fulfil the Wärtsilä SpecificationWärtsilä Specification Example: Palm oil, rape seed oil, olive oil, soya oil, sunflower oil, jatropha oil,
chicken oil, fish oil etc.
Refined biofuels such as Biodiesels (Transesterified bio oils)
Not Approved:– Wood pyrolysis oils
Eth l– Ethanol– Methanol– DME – Bio oils, alcohol blends
Chemical Compositions
Mineral oils H H H H H H H H H H HI I I I I I I I I I I
Decane (Paraffinic Molecule) Anthracene (Aromatic Molecule)
• Mineral oil based fuels are complex mixtures of different hydrocarbons
H-C-C-C-C-C-C-C-C-C-C-C-HI I I I I I I I I I IH H H H H H H H H H H
Vegetable oils and Animal Fats
• Chemically vegetable oils and animal fats are composed of triglycerides i e glycerolare composed of triglycerides, i.e. glycerol bound to three fatty acid molecules
• Vegetable oils typically contain 10-12 % Rn = Fatty acid
oxygen which enables good combustion properties but a lower calorific value
Triglyceride
Biodiesel
• According to EN 14214 biodiesel is defined as fatty acid methyl esters FAME
Is accepted in most car diesel engines– Is accepted in most car diesel engines – Can replace LFO for Wärtsilä engines (as main, back-up and pilot fuel)
BiodieselProduction
Pl t
Biodiesel (Fatty Acid Alkyl Ester)
Triglycerides(Vegetable Oil or Animal Fat)
PlantTransesterification Glycerol (Glycerine)Methanol or
Ethanol
CH2-OOR1 CH3OH R1-COOCH3 CH2-OHI NaOH (Catalyst) ICH-OOR2 + CH3OH R2-COOCH3 + CH-OH I II I CH2-OOR3 CH3OH R3-COOCH3 CH2-OH
Triglyceride Methanol Fatty Acid GlyerolMethyl Ester(Bi di l)(Biodiesel)
Characteristics of vegetable oils
Ash content – The ash content can vary depending on quality and
production/refining processesInfluence particulate emissions in exhaust gases
Palm Oil 22°C Palm Oil 60°C
– Influence particulate emissions in exhaust gases
Temperature control – (The oil viscosity is temperature dependent– Too cold -> wax formation (solidification of fatty acids )– Too hot -> polymerization (especially in the presence of oxygen)
Phosphorus contentosp o us co te t– Lifetime of DeNOx & OxiCat
Acid numberCan cause corrosion– Can cause corrosion
Lower heating value– The LHV of vegetable oils is typically 10-12 % lower than the LHV
f i l ilS °C S °C of mineral oils– More fuel rack – more stress on fuel injection equipment
Palm Stearin 22°C Palm Stearin 60°C
Liquid Biofuel handling
Acceptable storage period for liquid biofuels can be significantly shorter than storage period specified for fossil fuels. Many biodiesel manufacturers are referring to max. one month storage period After that acidity starts to increase leadingmonth storage period. After that acidity starts to increase leadingto faster oxidation rate of the fuel.
Straight liquid biofuels must not be mixed with fossil fuels, but have to be used as such Mixing of straight liquid biofuel andhave to be used as such. Mixing of straight liquid biofuel and distillate fuel will increase the risk of cavitation in the fuel system, since required fuel temperature before engine is normally 80 - 90 °C. At this temperature light fractions of distillate fuel will already start to evaporatealready start to evaporate.
Mixing of straight liquid biofuel with heavy fuel will increase the risk of biofuel component polymerization leading to formation of gummy deposits since the use of heavy fuel wouldformation of gummy deposits, since the use of heavy fuel would require much higher operating temperature than straight liquid biofuel, i.e. normally above 100 °C in order to achieve a proper injection viscosity.
Renewable biodiesel on the other hand can be mixed with fossil distillate fuel.