Waste Vegetable Oil As A Diesel Replacement Fuel
Phillip Calais and AR (Tony) Clark
Environmental Science, Murdoch University, Perth, Australia,
pcalais@ieee.org
Additions, updates and adaptions to ESN by Hakan Falk.
Abstract
In the past, waste edible oils and fats were often used in the
production of animal feeds. However due to links between BSE and this practice,
the use of waste fats for animal feed is not as common as it once was and this
has resulted in surplus quantities becoming available. This has led to
significant disposal problems.
Waste oils and fats can be used as renewable fuel resources.
Conversion of waste oils and fats to biodiesel fuel is one possibility but poses
some difficulties such as in the use of toxic or caustic materials and
by-product disposal. Conversion to biodiesel may also decrease the economic
attractiveness of using waste oils as fuels.
An alternative to the use of biodiesel is the use of vegetable
oils or rendered animal fats as a fuel.
Using relatively unmodified oils or fats eliminates the
problems associated with toxic and caustic precursor chemicals and residual
biodiesel alkalinity as the oil is used without altering its chemical
properties.
This paper discusses the use of waste vegetable and animal oils
and fats as unmodified fuels in compression ignition engines.
Introduction
Waste edible oils and fats pose significant disposal problems
in many parts of the world. In the past much of these waste products have been
used in the production of animal feeds. However due to possible links between
BSE and this practice, the use of waste edible animal fats for animal feed is
not as common as it once was, resulting in disposal problems. As it is often
difficult to prevent the contamination of waste vegetable oil with animal
products during cooking, waste vegetable oil often must be treated in a similar
manner as is waste animal fats.
One possibility for the disposal of these products is as a fuel
for transport or other uses. Conversion of waste oils and fats to biodiesel fuel
has many environmental advantages over petroleum based diesel fuel. However it
is not commercially available in Australia and the ‘back-yard’ production of
biodiesel may present serious risks as the process uses methanol, a toxic and
flammable liquid, and sodium or potassium hydroxide, both of which are caustic.
By-product disposal may present further difficulties and environmental
considerations may preclude production in sensitive areas.
An alternative to the use of biodiesel is the use of vegetable
oil or rendered animal fats as fuel.
Using unmodified oils not only eliminates problems such as
residual biodiesel alkalinity by-product disposal, but also increases the
economic viability of using the oil or fat.
While the use of vegetable or animal oils and fats as fuels may
be somewhat surprising at first, when examined in an historical context we can
see that the compression ignition engine, first developed to a usable level of
functionality by the French-born Rudolf Diesel near the end of the
19th century, was originally designed to operate on vegetable
oil.
In 1900, Rudolf Diesel demonstrated his new compression
ignition engine at the World Exhibition in Paris running on peanut oil. In 1911
he wrote "The engine can be fed with vegetable oils and would help considerably
in the development of agriculture in the countries that use it." [1]
It was about this time that new drilling technology and
exploration techniques were developed and together these ushered in the age of
cheap and plentiful fossil fuels. Consequently, the use of vegetable and animal
oils and fats as fuels has only been used for a few special purposes such as in
racing fuels or in environmentally sensitive areas where petroleum spills tend
to cause more serious problems than do spills of animal and/or vegetable derived
fuels.
After some one hundred years of using liquid petroleum fuels,
we are now finding that there are unforeseen side effects, the foremost perhaps
being the so-called Enhanced Greenhouse Effect.
In Australia, transport use contributes some 16% of Australia’s
greenhouse gas emissions. Of this, diesel fuel contributed about 17% or
11,705,000 tonnes of CO2 equivalent. An additional 1,622,000 tonnes
is released from diesel fuel used for electricity generation. [2] On top of
greenhouse gas emissions is the vexing question of how little – or much – is
left.
However oils of vegetable and animal origin, unlike fossil
fuels, have to potential to be produced not only on a sustainable basis but also
could be greenhouse gas neutral, or at the very least, emit substantially less
greenhouse gases per unit energy than do any of the fossil fuels.
Properties of Triglycerides as Fuels
A large amount of research has gone into examining Diesel’s
dream of using raw vegetable oils as fuels and when one speaks of growing crops
for liquid fuels it is often assumed that the oil will be used after only basic
extraction and filtering. [3,4,5]
Work has been conducted to examine these oils as fuel
replacements or additives. For example in the late 1970’s and early 1980’s,
research was undertaken at Murdoch University (Perth, Australia) into the use of
eucalyptus and other plant oils as a fuel component. [6] In New Zealand, there
are considerable problems with the disposal of surplus tallow from the processed
meat industry and a large amount of work was conducted in the early 1980’s on
the use of tallow as a fuel. [7]
Experience has shown that the use of unsaturated triglyceride
oils as a fuel may cause significant problems that can affect the viability of
their fuel use. [8] But this is not always the case and in many circumstances
these problems can either be dealt with or are acceptable to the user.
While power output and tailpipe emissions using plant or animal
oils are in most cases comparable with those when running on petroleum diesel
fuel, the main problem encountered has due to the higher viscosity of the
triglyceride oils and their chemical instability. These can cause difficult
starting in cold conditions, the gumming up of injectors and the coking-up of
valves and exhaust. [3]
The viscosity of plant and animal fats and oils varies from
hard crystalline solids to light oils at room temperature. In most cases, these
‘oils’ or ‘fats’ are actually a complex mixture of various fatty acids
triglycerides, often with the various components having widely varying melting
points. This may give the oil or fat a temperature range over which
solidification occurs, with the oil gradually thickening from a thin liquid,
through to a thick liquid, then a semi-solid and finally to a solid.
High melting points or solidification ranges can cause problems
in fuel systems such as partial or complete blockage as the triglyceride
thickens and finally solidifies when the ambient temperature falls. [3] While
this also occurs with petroleum based diesel, particularly as the temperature
falls below about ~ -10 to -5° C for ‘summer’
formulations and ~ -20 to -10° C for ‘winter’ diesels,
it is relatively easy to control during the refining process and is generally
not a major problem.
Many vegetable oils and some animal oils are ‘drying’ or
‘semi-drying’ and it is this which makes many oils such as linseed, tung and
some fish oils suitable as the base of paints and other coatings. But it is also
this property that further restricts their use as fuels.
Drying results from the double bonds (and sometimes triple
bonds) in the unsaturated oil molecules being broken by atmospheric oxygen and
being converted to peroxides. Cross-linking at this site can then occur and the
oil irreversibly polymerises into a plastic-like solid. [9]
In the high temperatures commonly found in internal combustion
engines, the process is accelerated and the engine can quickly become gummed-up
with the polymerised oil. With some oils, engine failure can occur in as little
as 20 hours. [10]
The traditional measure of the degree of bonds available for
this process is given by the ‘Iodine Value’ (IV) and can be determined by adding
iodine to the fat or oil. The amount of iodine in grams absorbed per 100 ml of
oil is then the IV. The higher the IV, the more unsaturated (the greater the
number of double bonds) the oil and the higher is the potential for the oil to
polymerise.
While some oils have a low IV and are suitable without any
further processing other than extraction and filtering, the majority of
vegetable and animal oils have an IV which may cause problems if used as a neat
fuel. Generally speaking, an IV of less than about 25 is required if the neat
oil is to be used for long term applications in unmodified diesel engines and
this limits the types of oil that can be used as fuel. Table 1 lists various
oils and some of their properties.
The IV can be easily reduced by hydrogenation of the oil
(reacting the oil with hydrogen), the hydrogen breaking the double bond and
converting the fat or oil into a more saturated oil which reduces the tendency
of the oil to polymerise. However this process also increases the melting point
of the oil and turns the oil into margarine.
As can be seen from Table 1, only coconut oil has an IV low
enough to be used without any potential problems in an unmodified diesel engine.
However, with a melting point of 25° C, the use of
coconut oil in cooler areas would obviously lead to problems. With IVs of 25 –
50, the effects on engine life are also generally unaffected if a slightly more
active maintenance schedule is maintained such as more frequent lubricating oil
changes and exhaust system decoking. Triglycerides in the range of IV 50 – 100
may result in decreased engine life, and in particular to decreased fuel pump
and injector life. However these must be balanced against greatly decreased fuel
costs (if using cheap, surplus oil) and it may be found that even with increased
maintenance costs that this is economically viable.
Table 1 Oils and their melting point and Iodine Values
[11]
Oil Approx. melting Iodine
point ° C Value
Coconut oil 25 10
Palm kernel oil 24 37
Mutton tallow 42 40
Beef tallow 50
Palm oil 35 54
Olive oil -6 81
Castor oil -18 85
Peanut oil 3 93
Rapeseed oil -10 98
Cotton seed oil -1 105
Sunflower oil -17 125
Soybean oil -16 130
Tung oil -2.5 168
Linseed oil -24 178
Sardine oil 185
All of these problems can be at least partially alleviated by
dissolving the oil or hydrogenated oil in petroleum diesel. ‘Drying oils’ such
as linseed oil for example, could be mixed with petroleum diesel at a ratio of
up to about 1:8 to give an equivalent IV in the mid-twenties. Likewise coconut
oil can be thinned with diesel or kerosene to render it less viscous in cooler
climates. Obviously the solubility of the oil in petroleum also needs to be
taken into account. [7]
Another method is to emulsify the oil or fat with ethanol.
Goering [12] found that eight parts of soybean oil, when emulsified with two
part ethanol and five parts of 1-butanol as stabiliser, performed as well as
diesel fuel and was able to start a cold engine. The cost was calculated (in
1981) to be $0.40 a litre as compared to $0.30 – 0.35 per litre for diesel.
Trans-esterifying triglyceride oils and fats with monohydric
alcohols to form biodiesel largely eliminates the tendency of the oils and fats
to undergo polymerisation and auto-oxidation and also reduces the viscosity of
the oil to about the same as petroleum diesel.
However as previously mentioned, the ‘back-yard’ production of
use of does pose some risks, particularly to those who are not familiar with the
handling of toxic and highly flammable liquids.
In many cases, it is possible to use a variety of triglyceride
fats and oils as a fuel. While engine wear and maintenance may be increased, in
some circumstances these problems are not serious enough to prevent the use of
the triglycerides as a fuel.
Conversion of a vehicle to operate on Waste Cooking Oil
An alternative to the use of biodiesel is the use of vegetable
oil or animal fats as a fuel. The differences amongst fats and oils, whether of
animal or vegetable origin, relate mainly to the level of saturation in the
carbon chain. Generally speaking, the lower the number of double bonds, the
higher the melting point of the triglyceride and the greater the stability of
the triglyceride to polymerisation and spontaneous oxidation. From an engine use
point of view, it is preferable to use saturated fats as fuels as they are more
stable and less resistant to oxidation, particularly under the elevated
temperatures and pressures as found in an engine environment. However due to
their higher melting points, difficulty may be encountered in starting the
engine without pre-heating of the fat.
In order to test the viability of using relatively unsaturated
oils in engines, a 1990 Mazda with a 2.0 litre indirect injection OHC diesel was
obtained with a view of running it on various types of triglyceride oils and
fats. At that time of purchase, the vehicle had covered 222,000 km.
The previous owner stated that the engine head had been
overhauled, but no further details were provided. Since the purchase, and prior
to the conversion to operate on triglyceride oils, the injector pump was
overhauled. Fuel consumption of the vehicle on diesel was stable at about 6.9
L/100 km.
The vehicle is used as a family vehicle in a 2-car household.
At the time of conversion (October 2000), the vehicle had covered 231,000
km.
Waste palm oil (a solid fat) was used initially but the time
delay in melting this oil prevented use of the oil on short journeys.
Consequently, waste canola oil was tried and has been used exclusively for the
last 7,500 km.
At about 80 cSt (at 20° C), the
viscosity of used canola oil is significantly greater than that of diesel which
has a viscosity in the range of 2 to 4.5 cSt. [7, 13] However, as canola oil is
warmed, its viscosity falls quite significantly and at about 70° C the viscosity is about 5 to 10 cSt. Thus the viscosity is
sufficiently low to allow its use as a replacement fuel for diesel with out too
much difficulty.
Table 2 Comparison of properties of diesel, canola oil and commercial US
biodiesel. [7, 13, 14]
Diesel Canola Oil Biodiesel
Density kgL-1 @ 15.5° C 0.84 0.92
0.88
Calorific value MJL-1 38.3 36.9 33 – 40
Viscosity mm2s-1 @ 20° C 4 - 5
70 4 – 6
Viscosity mm2s-1 @ 40° C 4 - 5
37 4 – 6
Viscosity mm2s-1 @ 70° C 10
Cetane number 45 ~ 40 - 50 45 – 65
The vehicle was fitted with an additional 17 litre fuel tank
under the bonnet together with the necessary fuel lines, additional filter and a
solenoid valve to control the fuel source. Electrical connections to a
thermostat, glow plug, run-on timer, switches and the solenoid valve were also
installed.
The oil tank was fitted with a heat exchanger
comprising one metre of 12 mm copper tube. This was connected to the engine
coolant system and pre-heats the oil in the tank. The tank was located in the
engine bay to maximise heat transfer to the tank and to keep the coolant lines
short. The finished tank had a useable capacity of seventeen litres. This gave a
range of up to 240 km between refuelling.
Additional filtering was installed with an internal preheater.
The pre-heater, a 24 V diesel glow plug, together with a relay and thermostat
was installed so that if a solid fat was used for fuel, any solidified fat in
the filter chamber could be quickly melted. The filter used (Ryco Z30) provides
filtration to 30 micron.
A vacuum gauge was fitted after the fuel filter and it was
found that at start-up with cold canola oil, fuel flow was insufficient causing
a vacuum in the fuel line and filter. An extra in-line fuel pump was added
before the filter and this alleviated this problem and has increased fuel filter
life.
The heated oil fuel line was one metre of 5/16" semi rigid
nylon tube encased in a 5/8" rubber coolant pipe. Brass fittings were used to
ensure minimal corrosion and leakages of coolant.
The three port, 12 Vdc solenoid valve was mounted in close
proximity to the fuel pump to minimise changeover lag. The fuel return line to
the diesel tank was redirected to the fuel pump suction side between the
solenoid valve and fuel pump. This was done to prevent the oil in the return
line going to the diesel tank. A disadvantage of this is that the fuel system
became rather intolerant of air in the system.
A run-on timer was installed using a modified ‘turbo timer’.
After the solenoid valve is switched back to diesel, the timer keeps the engine
running for a period of time, even if the vehicle is parked and the key removed
from the ignition. During this period, the oil in the injector pump is gradually
replaced by diesel and after several minutes, only diesel remains in the fuel
pump, filter, fuel lines and injectors. The correct time was found by a trial
and error. A manual override switch was also installed to allow emergency, or
short duration stopping of the engine.
The supplier of the used oil (a fast food outlet) filters the
oil and puts it into containers for collection. To ensure that the oil is clean,
the oil is heated and additionally filtered through a 5 micron bag filter. It
was found that the used oil usually becomes cloudy and this was found to be a
combination of the oil starting to solidify due to partial de-unsaturation of
the oil from use and minor water content. If water content is suspected of being
excessive, the oil is heated above 100’C to evaporate the moisture.
Use of the oil and preliminary results
To date, the vehicle has been driven over 7500 km using canola
oil. In the morning, the oil in the tank is cold and quite viscous and a
particular start-up routine must be used. In addition, if, at the end of the
trip, the vehicle will not be restarted again for several hours, then a shutdown
sequence must be followed in order to allow easy restarting.
Glow plugs are used for all starts. When starting cold, the
engine is started on diesel and the journey commenced. When the engine
temperature has reached ‘normal’ as shown on the engine temperature gauge, the
fuel solenoid is operated, and the journey continues using vegetable oil. For
hot or warm starts, the engine is started using the vegetable oil.
Shutdown: In the cooler months, at about 5 km from the end of
each journey, the fuel solenoid is released. At the end of the journey, the
ignition switch is turned off. If the time delay has not expired, the engine
continues to idle, until the end of the delay. During warmer periods, the
shutdown delay override switch is used to stop the engine for all stops, except
for the last journey of the day.
Comparison of performance and economy
Using records of fuel consumption and distance travelled, there
has been no noticeable difference in fuel consumption or engine power when
operating on diesel, palm or canola oil. The fuel consumption has been found to
be approximately 6.9 L/100 km, regardless of what fuel is being used. It is
planned that full testing of performance will be carried out in the near future,
taking into account different driving conditions and different fuels.
Problems
Cold starting with canola oil: If the engine has been
allowed to cool completely (eg overnight) and the shutdown routine not followed,
then the engine may be very difficult to restart. It has been found that heating
the injectors by, for example, pouring hot water over them or using a hair
dryer, will allow the engine to restart with no difficulty.
Saturated oils: The use of saturated (solid) fats in
cooler months would require significant improvements to the heat exchanger in
the oil tank. Palm oil tended to solidify in the filter (prior to a glow plug
heater being installed) and in the front half of the tank while travelling,
reducing useable capacity. This may be less of a problem if a 6 port solenoid
valve were to be used, circulating heated oil back to the tank, and improving
the heating of the oil in the tank.
Carbon build up causing wear: Reports have been made of
accelerated engine wear due to increased carbon deposits in combustion chambers.
[3, 4, 7] As the engine condition at the start of the test was not accurately
measured, no proper evaluation of the wear can be made. However, at the end of
the vehicle life, the engine will be dismantled and evaluated for any abnormal
evidence of wear or damage.
Galvanised Fuel tank: The oil tank was made from scrap
galvanised steel sheet metal. It was found that the oil reacted with the zinc
plating and this resulted in globules of reacted oil blocking the fuel filter on
many occasions. The oil tank was consequently removed, cleaned and acid etched
to remove the zinc coating. No reacted fuel globules have been observed
since.
Costs:
The tank was made using scrap materials and consequently was of
negligible cost. It was estimated that if professionally made using new
materials, it would have cost approximately $400. Other expenses were: filter -
$30, filter elements - $5, heated fuel line - $120, solenoid valve - $95, sundry
items - $100. The total cost was $250. Operating costs are $5 per 10,000 km for
new filter elements
Exhaust emissions:
At this stage no exhaust emission tests have been done. The
level of particulates as gauged by simple visibility checks appears about the
same whether running on diesel or canola oil. However, as the oil contains no
sulphur, SO2 emissions are not present when running on triglyceride
oils. Furthermore, the pungent smell typical of diesel exhaust is not present.
Rather the smell is similar to that of a BBQ.
Life-cycle CO2 emissions are substantially reduced.
Studies done by Sheehan et al, Beer et al etc indicate that reductions by as
much as 80 to 90% compared to fossil diesel fuel can be expected, given the
renewable nature of the oil, and that this is a re-use of a spent product. [14,
15, 16, 17]
Nitrogen oxides (NOx) emissions would most likely be
similar or slightly elevated by ~10% as compared to fossil diesel. In addition
to atmospheric nitrogen, most vegetable and animal oils contain small quantities
of nitrogen containing proteins, which upon combustion, release various nitrogen
oxides. [14, 15, 16, 17]
Unburnt hydrocarbon emissions may or may not be increased.
Previous research has shown that this is very dependent of the vehicle’s state
of tune, age and the specific properties of the oil. [7, 14, 16, 17]
Cost efficiency:
Using free waste canola oil, fuel costs have been only for the
diesel fuel used in the start-up and shutdown periods. Fuel purchase records for
10,000 km show the vehicle has used 240 litres of diesel. Driving this distance
on diesel only would normally require approximately 690 litres of fuel. This
represents a fuel cost saving of 65%. The conversion has paid for itself with
savings in diesel purchases in excess of $400.
Different usage patterns would give obviously give different
results. Usage patterns for this vehicle show mainly short trips, with one or
two longer (>20 km) journeys per week.
As vehicle use increases, the diesel fuel savings would also be
expected to increase. The only requirement for diesel, is that the motor must be
allowed to reach operating temperature before operating on triglyceride oils,
and that the oil must be diluted or purged from the fuel pump before
shutdown.
Due to higher fuel usage larger vehicles would be able to have
greater fuel cost savings which would more than offset the increased costs of a
remotely located oil tank.
Obviously, if there were to be a greater demand for used and
waste cooking oil, the oil may not be available free and the cost of purchasing
waste oil must then be taken into account. While this would extend the pay-back
period, as long as there was a reasonable difference between the cost of the
waste oil and diesel fuel and any extra maintenance costs were not too
excessive, it would probably still be economically viable to undertake the
modifications and operate on used oil.
Possible improvements
Solenoid Valve: The use of a six port solenoid valve and an
alterative fuel line set-up would reduce the shutdown delay requirement, as the
return line would not be fed back into the fuel pump.
Fuel filter: The provision of a heated fuel filter, using
filter elements giving 5 micron filtration would protect the fuel pump from the
possible 5 – 30 micron particles not removed by the Ryco Z30 filter. Filter
heating would be most effective if heated by engine coolant.
Biodiesel: Starting the vehicle on biodiesel would further
enhance the environmental benefits obtainable.
Conclusion
Many vegetable and animal oils can be used as diesel
replacement fuels. The two ways of doing this are to either use the oil as a
straight fuel or to convert the oil to a methyl or ethyl ester (biodiesel). Both
of these ways have various advantages and disadvantages. One of the authors
(Clark) converted a Mazda 626 to operate on straight vegetable oil and has done
over 7500 km using this method. The other author (Calais) has been using
biodiesel in an unmodified Toyota Corolla for over 20,000 km.
In converting the Mazda 626 to operate on straight oil, a small
tank was fitted under the bonnet of the vehicle. In order to minimise fuel
‘cold-plugging’ problems due to high fuel viscosity, both the tank, filter and
fuel lines are heated. The vehicle is first started on diesel and then when the
engine has reached normal operating temperature and the oil has been heated, a
solenoid valve is operated which switched the fuel system over to the oil.
To date there has been no evidence of increased engine wear,
lubricating oil dilution or other problems. However the experience of others has
shown that increased engine wear may occur but as yet it is still too early to
determine whether or not this will occur in this example. Even so, the economic
benefits obtained by using waste canola oil may more than offset any extra
engine maintenance costs.
It is hoped that continuing research on this project may
provide more information about this in the future.
References
- Tickell, J. The Great American Veggie Van Adventure,
http://veggievan.org/
- Australian Greenhouse Office Australia’s State and Territory Greenhouse
Gas Inventory – Western Australia, Commonwealth of Australia, Canberra,
1999
- Pullan, C. et al Research Priorities for Transport Fuels from Biomass
and Other Sources for Western Australia, Energy Advisory Council of WA,
Perth, 1981
- Parker, A.J. et al Transport Fuels from Biomass. Research
Opportunities Symposium Proceedings, March 1980, Perth.
- Australian Greenhouse Office Alternative Fuels Program – Issues Paper,
Commonwealth of Australia, Canberra, 1999
- Barton, Alan (Prof) Personal communication, Murdoch University, 1999
- Sims, R. Yields, Costs and Availability of Natural Oils/Fats as Diesel
Fuel Substitutes, Report No LF2021 for the Liquid Fuels Trust Board,
Wellington (NZ) 1982
- SECWA (Now Western Power), Evaluation of Rapeseed and Sunflower oil in
a Stationary Diesel Generator, NERDDC Project No 80/0294, Januar 1984
Perth
- Cole, A.R.H, Watts, D.W. & Bucat, R.B. Chemical Properties and
Reactions University of Western Australia Press, Perth, 1978
- Duke, J. A. Handbook of Energy Crops, (written 1983) Unpublished on
paper but available from
http://www.hort.purdue.edu/newcrop/duke_energy/dukeindex.html
- Lide, D.R. et al Handbook of Chemistry and Physics, 76th
Edition, CRC Press, Boco Raton, USA, 1996
- Goering, B. USDOE Seminar II. Vegetable Oils as Diesel Fuel, Oct.
21, 22, 1981
- Environment Australia (National Heritage Trust) (2000b). Setting
National Fuel Quality Standards – Paper 2 - Proposed Standards for Fuel
Parameters (Petrol and Diesel), Canberra
- Beer, T., Grant, T., Brown, R., Edwards, J., Nelson, P., Watson, H.,
Williams, D. (2000) Life-Cycle Emission Analysis of Alternative Fuels for
Heavy Vehicles. CSIRO, Australia
- Calais P. & Sims, R. A Comparison Of Life-Cycle Emissions Of Liquid
Biofuels And Liquid And Gaseous Fossil Fuels In The Transport Sector,
Proceedings of Solar 2000, Brisbane 2000
- Beer T. et al Comparison of Transport Fuels, Report EV45A/2/F3C for
the Australian Greenhouse Office, 2001
- Sheehan, J., Camobreco, V., Duffield, J., Graboski, M., Shapouri, H.
(1998). An Overview of Biodiesel and Petroleum Diesel Life Cycles.
NREL, Golden, Colorado.
Bibliography
Department of Energy Alternatives to Traditional Transport Fuels 1996,
Energy Information Administration, US Department of Energy, Washington DC,
1997
Environment Australia (National Heritage Trust) (2000a). Setting National
Fuel Quality Standards – Proposed Standards for Fuel Parameters (Petrol and
Diesel), Canberra
Peterson, C.L. & Reece, D. On-Road Testing of Biodiesel – A report of
past research activities, Department of Agricultural Engineering, University
of Idaho, 1996
Quick, G.R. A summary of some current research in Australia on vegetable
oils as candidate fuels for diesel engines. Seminar II, USDA, Peoria, IL.,
1981
Sims, R., (1996). The Potential for Biodiesel in New Zealand.
Proceedings of Conference ‘Applications of Bioenergy Technologies’ Rotarua, pp
139 – 148 EECA.
Sims, R., (1995). The Biodiesel Research Program of New Zealand.
Proceedings of the Second Biomass Conference of the Americas, Oregon, pp 849 –
858, NREL.
© Copyright energysavingnow.com 2000.
© Copyrights to Software @ this site
|
