Fatty Acid Methyl Ester Fuels
as a Replacement or Extender for Diesel Fuels
Diesel Fuel Injection Equipment Manufacturers
Common Position Statement

Background:
Diesel Fuel Injection Equipment (FIE) manufacturers fully support the development of alternative sourcesof fuel for compression ignition engines.
In Europe and in the United States, fuel resources such as Rape Methyl Ester (RME) and Soybean
Methyl Ester (SOME), collectively known as Fatty Acid Methyl Esters (FAME) are being used asalternatives & extenders for mineral oil derived fuels.
The introduction of any change in fuel composition needs to be fully assessed by those responsible,
before these fuels are made available to the public. The need for thorough evaluation has beenhighlighted in recent years with the changes made to remove sulphur from mineral oil diesel fuels, whichcaused excessive wear and failure of rotary fuel injection equipment. In this case, release of the fuels
took place before a suitable lubricity standard was in place to protect end-users from product failures.
The FIE manufacturers are aware of issues peculiar to fatty acid methyl ester fuels and are active in thegeneration of Standards for these fuels to protect the end-users of their products from potential
premature failure. Biodiesels must conform to such Standards to be of acceptable quality, just as
mineral oils do at present.
To date, experience in Europe has been mainly associated with the methyl esters of Rapeseed oil andin the US with Soybean derived fuels. Whether or not the service experience with these fuels will apply/
extend to all fatty acid methyl esters (including such as Tallow ME and Used Frying Oil ME) has yet tobe determined. FAMEs tested so far appear to have good lubricity and cetane numbers.

FIE Manufacturers Concerns:
FAMEs are derived from a wide range of base stocks, resulting in a similarly wide range of finished fuelcharacteristics.
Amongst the concerns of the FIE manufacturers are the following fuel characteristics:- Free methanol- Dissolved and free water- Mono and di glycerides- Free fatty acids- Alkaline metal compounds in solution.

- Free glycerin- Total solid impurity levels
Oxidation and thermal stability

As currently manufactured, these fuels are less stable than mineral oil derived fuels. FAME fuels readily“bio-degrade” in the event of accidental spillage or leakage - this is claimed as a marketing advantageThe degradation propensity is, however, of major concern to the FIE manufacturers as the products ofthis natural process can be potentially harmful to the fuel system.

FAME Fuel - Joint FIE Manufacturers Statement, issued June 2000

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Our tests have shown that fuel degradation can take place in the fuel supply chain and in the vehicle fuelsystem; it is accelerated by the presence of oxygen, water, heat and impurities. The products of biodegradation have been shown to be corrosive (e.g. formic, acetic and organic acids, water andmethanol) and polymerisation products drop out within mixes with mineral fuels.
During extensive field trials conducted by the FIE Manufacturers in collaboration with end-users, thefollowing injection equipment and engine problems have been identified as being caused by these fuelcharacteristics:- Corrosion of FIE components.
- Elastomeric seal failures- Low pressure fuel system blockage- Fuel injector spray hole blockage- Increased dilution and polymerisation of engine sump oil- Pump seizures due to high fuel viscosity at low temperatures- Increased injection pressure
The incidence of these effects is likely to be increased when the engine is in irregular use, inapplications such as stand-by generator units, automatic plant and seasonally used vehicles. ( A list ofpotential problems is attached at the end of this document)

Fuel Quality Control Requirements:
Several initiatives are currently underway, to define Standards for fatty acid methyl ester fuels. For
vegetable oil methyl esters (VOME), Austrian, Italian, German and French Standards already exist as
well as a draft European Standard, but it is recognised that these do not fully specify the fuelrequirements to a sufficient level to protect the end-user. In particular the fuel ageing propensity is poorly
defined and few controls are implemented.
Within the European Community, CEN technical committee TC19 has been given the responsibility toevolve Standards of FAME for diesel engine use, viz.,a) 100% FAME as a complete replacement for diesel fuelb) FAME fuel as a blending component for use with mineral diesel fuel to comply with EuroNorme
EN590 with up to 5%(vol) FAME.
International Standards Organisation committee TC28 will liaise with this group with regard to an
eventual world-wide standard. ASTM in the U.S. is involved in similar work.
The latest proposed draft German specification from DIN for FAME (E-DIN51606) contains most of theitems proposed by the FIE manufacturers for inclusion in an acceptable standard. Uppermost in theserequirements are the following:- Oxidation Stability- Thermal Stability- Total Acid Number- Iodine Number- Water Content- Content of methanol, free glycerine & glycerides

Flash Point- Low Temperature Operability parameters such as viscosity, CFPP & pour point.
It is anticipated that, to reach acceptable levels for these parameters the development and inclusion ofsuitable fuel additives and appropriate test methods will be required.
For determination of oxidation stability, it is being proposed to use a modified IP306 procedure. Current
experience suggests that the best of the FAME fuels tested cannot better an “induction period” of fourhours. Fuels without additives to improve this characteristic are of concern to the FIE manufacturers

FAME Fuel - Joint FIE Manufacturers Statement, issued June 2000

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Diesel Fuel Injection Equipment Manufacturers

Common Position Statement on Fatty Acid Methyl Ester (FAME)
Fuels as a Replacement or Extender for Diesel Fuels

The FIE Manufacturers Position:
FIE manufacturers encourage the development of renewable compression ignition fuels. Experience
to date with Rapeseed Methyl Ester fuels in Europe suggests that with fuels conforming to theexisting national FAME standards at the point of sale in mixtures containing up to 5% volume RME,
in mineral diesel fuel complying with currently accepted quality Standards, should not give end-users
any serious problems.
Certain vehicle models have been adapted by their makers to use blends of 5% and above of goodquality RME fuels in mineral diesel fuel. Other vehicles are adapted for using 100% good quality
RME. The FIE manufacturers can supply equipment suitable for these applications.
The original quality of the FAME fuel is defined in draft National Standards which cover all relevant
impurities and tramp chemicals from the processing. Suppliers of FAME fuels must be able todemonstrate compliance to these draft Standards at the point of delivery to the vehicle or plant.
International Standards are based on experience gained with the National Standards being developed
to specify the original quality and long term stability of FAMEs. For the FIE manufacturers a key partof these Standards is resistance to oxidation. Aged or poor quality FAME contains organic acids,
free water, peroxides and products of polymerisation which attack many components thereby
drastically reducing the service life of the FIE. A full list of issues which have been witnessed inservice is in the Attachment.
Even if these fuels comply with a suitable Standard as delivered, the enhanced care and attentionrequired to maintain the fuels in vehicle or other tanks may entail a high risk of non-compliance to theStandard during use.
The FIE manufacturers can accept no legal liability for failure attributable to operating their productswith fuels for which the products were not designed, and no warranties or representations are madeas to the possible effects of running these products with such fuels.
Non-compliance of the fuel to Standards agreed by the FIE manufacturers, whether being evident byappearance of the known degradation products of these fuels, or their known effects within the fuelinjection equipment, (see attached list of known issues) will render the FIE Manufacturers’ guarantee
null & void.

FAME Fuel - Joint FIE Manufacturers Statement, issued June 2000

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Attachment

Fuel injection equipment - potential problems with FAME
(non exhaustive list)

Fuel Characteristic

EffectFailure ModeFatty acid methyl esters (general)-Causes some elastomers including
Nitrile rubbers to soften, swell, or
harden and crack

Fuel Leakage

Free methanol in FAME-Corrodes aluminium & zinc-Low flash point

Corrosion of FIE

FAME process chemicals

Potassium and sodium compounds
Solid particles

Blocked Nozzles

Dissolved water in FAME

Reversion of FAME to fatty acid

Filter Plugging

Free water in mixtures

Corrosion
Sustains bacteria
Increases the electrical conductivityof fuelCorrosion of FIE
Sludging

Free glycerine

Corrodes non ferrous metals
Soaks cellulose filters
Sediments on moving parts andLacquering

Filter clogging

Mono- & di-glyceride

Similar to glycerine

Free fatty acid

Provides an electrolyte and hastens
the corrosion of zinc
Salts of organic acids
Organic compounds formed

Injector Coking

Corrosion of FIEFilter plugging
Sediments on parts

Higher modulus of elasticity

Increases injection pressure

Potential of reduced
service life

High viscosity at low temperature

Generates excessive heat locallyin rotary distributor pumps
Higher stressed components

Pump seizures
Early life failures
Poor nozzle sprayatomisation

Solid impurities

Potential lubricity problems

Reduced service life

Corrodes all metallic parts
may form simple cell

Corrosion of FIE

Ageing products
Corrosive acids (formic & acetic)

Higher molecular organic acids

Similar to fatty acid

Polymerisation products

Deposits especially from fuel mixesFAME Fuel - Joint FIE Manufacturers Statement, issued June 2000

Filter plugging
Lacquering formation in
hot areas
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