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Biodiesel quality adjustments by additives and anti-oxidants
APEC Biodiesel Standard
Raoul [email protected]
In co-operation with HART ENERGY CONSULTINGwww.hartenergyconsulting.com
25 October 2007
Biodiesel vs PetroleumBiodiesel (FAME) DIFFERENT (to petroleum)
Chemistry is fundamentally different, so properties, performance & durability differences follow
So, risk for vehicles and vehicle technology of todayBiodiesel supply limited and growing slowly
so vehicles are designed for conventionalmodified or passed for biofuels with restrictions
Biodiesel standards are driven towards conventional diesel standards, ie. Performance
Coming from older standards base as vegetable oilsRequires specific standards for
Biodiesel – feedstock & process dependentBlends
AND ADDITIVES CAN ADDRESS
AdditivesDefinition:
“Agents that are added to fuels in a concentration of < 1%
Substances present in higher concentration, the term "fuel components" is more appropriate.”
Fuel additive categories:Multifunctional Diesel - market performanceRefinery Specification AdditivesAnti-Oxidant and Stability Control Additives
Additives may be designed for petroleum based fuels or increasingly are specifically modified for use with Bio-Fuel components
Additives: Effect & NeedChanging fuel parameters can cause unforeseen wear, deposit or combustion problems with corresponding impacts on engine performance and emissionsFuel additives can selectively restore specific performance characteristics of the fuelTest methods & standards can be established that correlate to long-term performance given sufficient time and data
Environmental concerns led to the introduction of Ultra Low Sulphur City Diesel in Sweden in 1991 and a subsequent rapid increase of fuel injection equipment (FIE) failuresrapid introduction of lubricity additives provided the solution….classic example of a reactive approachlubricity additive experience in Europe and correlation exercises with fuel pump wear have shown the HFRR test with a 460µm WSD to be a reliable and appropriate level to protect current fuel injection systems and on which to develop future systems
Biodiesel performance issuesAdditives: Biodiesel IssuesLow temperature operability – DIFFICULT TO ADDRESS
Elastomer compatability – NOT GENERALLY ADRESSED BY ADDITIVES
FIE (Fuel Injector Equipment) component compatability – METAL DEACTIVATORS & STABILITY
Deposit formation & storage stability – ADDRESSEngine oil dilution- NOT GENERALLY ADRESSED BY ADDITIVES
Exhaust (tailpipe) emissions – NO HARM
Lubricity – NOT NEEDED
Conductivity – ONLY FOR BLENDS
Cetane Number – MAYBE ONLY FOR BLENDS
Foaming – ONLY FOR BLENDS
Coldflow Additives for Biodiesel
The temperature at which pure (B100) biodiesel starts to gel varies significantly depending on the mix of esters and therefore the feedstock oil used to produce the biodiesellow erucic acid RME starts to gel at -10 °Cbiodiesel from tallow gels at +16 °C
There are a very limited number of products that will significantly lower the gel point of B100 biodiesel, particularly for high molecular mass biodiesels
Coldflow : RME with different diesels
Coldflow : RME vs SME blends
Coldflow Additives Effect: B100
Coldflow Additives : Treat rate
Coldflow Additives Effect
Stability and Oxidation
unsaturated fatty acid (feedstock dependent)loss of hydrogen >>> free radicalfree radical >>> fatty acid peroxide radicalfatty acid peroxide >>> hydroperoxidehydroperoxide >>> aldehydes, ketones
this process can be halted by an antioxidant converting the original free radical back to the fatty acid by donating hydrogen
Stability and Oxidationoxidation will be catalysed by trace metals
metal deactivator prevents this
Different fatty acid chemistries may respond better to different AO chemistries
formulated AO including mixed chemistries give a wider spectrum of protection
Anti-oxidants effective: Differences
Stability and Oxidation
Test Fuel: Commercial diesel fuel blended the FAME meets EN14214 by 5vol%
Test Fuel: Same FAME above with 400ppm of anti-oxidant (20ppm as B5)
Anti-oxidant additives effective
2nd Japan/Korea Petroleum Technology Seminar, October 24, 2006 in SEOUL, KOREA
Ref: JAMA
Tests
Anti-oxidant additives effective
Ref: JAMA
Tests
Anti-oxidant additives effective
Ref: JAMA
Tests
Oxidation Standard Development
ASTM Working GroupSignificant additional work is planned Test method precision and comparison
Rancimat and D 2274 Ability of each method to predict benefits of anti-oxidants in reducing sediments and deposits
Comparison of bench scale results to actual field operations with B20 and lower blends Determination if control of B100 stability is sufficient for all blend levels with all petrodieselControl at the B100 level is preferred
Anti Anti-oxidants are most easily added to B100 Blending is done at terminal
Monitor acid number as surrogate for stability
Detergency of Biodiesel
Summary
Biodiesel presents challenges for the automotive industryA need to define performance standards that ensure acceptable quality and operation of bio-fuels in the market placeFuel additives provide the only solutions for some performance issues that are faced by bio-fuels
Anti- oxidants for stability (rather than Iodine Number)Cold flow improvers for low temperature useRest are occasional or specific market use of additives
Standards need to be developed based on performance criteria to ensure that the full benefits of fuel additives are realised.
THANK YOU APEC Biodiesel Standard
Raoul [email protected]
In co-operation with HART ENERGY CONSULTINGwww.hartenergyconsulting.com
25 October 2007
Biodiesel additive development opportunities
APEC Biodiesel Standard
Raoul [email protected]
In co-operation with HART ENERGY CONSULTINGwww.hartenergyconsulting.com
25 October 2007