Vegetable oil as fuel for trucks 11

[austim]

I have a friend who is looking for good info regarding conversion of diesel engines (for trucks) to alternate fuels. In view of the current prices of standard diesel fuel, he is considering using vegetable oil.

Can anyone tell him
(a) what good reference sources are there?
(b) would such a fuel change require a change in
compression ratio (to perhaps increase the air
temperature at the time of injection)?

I have told him that we (ie the eng-tips community) should have all the knowledge that he requires. Please do not let me down

 

[Snork]

The fuel your friend is looking for is called biodiesel. I have never used it but have looked into it and have a co-worker who used to design diesel engines who knows a bit about it. By all accounts it works fairly well but has two catches. First, it jells at a higher temperature than regular diesel - important in cold areas. And second, it apparently degrades some polymers - such as fuel line - so be sure to check that before using a lot of it as this will clog injectors. I understand that one major trucking company is running their units on biodiesel but havn't been able to confirm this. Further information is avialable on the web if you search "biodiesel". Good luck.

 

[WGJ]

As ScottMc has already said, Biodiesel (or bio-mass derived fuels - fuels from sunflowers, soya, rape seed, linseed etc) has a bad effect on elastomers and polymers. Converting an 'old' engine to work with biodiesel will almost certainly cause any 'O' rings in the fuel system to develop leaks and some plastic parts to degrade. Plastic fuel tanks can also suffer - I have heard that the high density polyethylene tanks used for some applications can develop surface blisters as a result of the action of biodiesel.
Biodiesel fuels are methlesters (I'm no chemist) and the methanol content of the fuel can give problems when you want to store it. The methanal content will allow water to be absorbed and this will then allow bacteria to grow. I gather the water/bacteria presence then can also lead to formic acid being produced.
All in all, its just not a case of puttin a suitable biodiesel in the tank and driving off.
If you have a look at the SAE web site you'll see a good number of papers on the use of biomass diesel fuels, I think.
Outside of the USA, you'll find that there's a fair amount of interest in the use of biodiesel.

 

[romke]

as already has been mentioned, biodiesel reacts differently to polymers and various rubber compounds. This means in practice that when you changeover you will have to make sure that all the elastoners that come into contact with the fuel are compatible with biodiesel. In practice this means a rather costly operation of changing everything...Mercedes Benz and MAN for example have done extensive testing with biodiesel and are supplying replacement parts for various of their engine types.

There is another thing to be taken account. Since standard engine oil is designed to cope with the byproducts of combustion introduced in the oil by blowby, they are not necessarily suitable for use with a type of fuel that will produce byproducts with a different chemical nature. In practice this is accounted for by reducing the oil drain interval considerably, since no biodiesel-compatible oils are available on the market and problably will not be for the next few years unless the biodieselidea catches on.

This is actually not very likely since the cost of production is quite a bit higher then standard fuel. There are a few places in the world where actually trucks are running on biodiesel, but there it's either an experiment or the use of such a fuel is heavily subsidized for one reason or another (Germany, France).

The largest experience with biodiesel is with the manufacturers of agricultural equipment - eg John Deere. Within the farming community biodiesel is regarded as a potentially interesting "crop".

 

[teddy]

go to

http://journeytoforever.org/biodiesel_simon.html

that's the best place for you.

 

[taj9898gym]

no this the first time i see this so kindly forward and explain the process

 

You can also run any Diesel engine pure vegetable oil, Rudolf Diesel, the inventer of the Diesel engine tried it ages ago, but it never came out big! Either mix 50/50 with Diesel or pre-heat pure oil to 70 degrees celcius before entering fuel injection for better viscosity and combustion. Also reccomended is starting on Diesel till engine is warm (3 min.?), switching to vegy-oil and before stopping, switch back to diesel for a few mins. to rinse out oil.

 

[austim]

On behalf of my friend seeking info on alternate fuels for diesel engines - thankyou to all respondents. We seem to have created a pretty useful reference here.

 

[jamesm]

from what i have read from other tech peoples information it all seem relevent and true. A desiel engine will just about run on any old fuel such as the above vegy oils mentioned. I have herd of several different people running there desiels on used cooking oil being it vegetable or animal based product and quiet sucessfuly. But one of the problems along with seal issues is filtration. Youll probably find that youll be replacing fuel filters regularly. Also you might get stung by the local police for avoiding road tax? but its a step in the right direction for alternative fuels. hope this is relevant

 

[Whittey]

-------------- quote -----------
The Tartrais engine was capable of running on bituminous oil, fuel oil, paraffin oil, groundnut oil, castor oil or cod liver oil.
------------ end quote ---------

http://www.psa.fr/en_psaBB0026.html

Just goes to show you can run an engine on anything. The oldschool tractors are known to run on paraffin.


-=Whittey=-

 

[demonbarber]

Hi
An interseting question
Well Good old Rudolph Diesel ( the inventor)ran his demo model on peanut oil when he was demonstrating it for the first time in Germany.
There are a couple of links you might like to look at over her in the uk ( I have no connection with them)

http://www.geocities.com/vegoilcar/

However problems you might encounter are `solidification in low temperature areas and of course the ever present fuel tax (a problem here in the UK)
A concern is that pump pressures need to be generaly higher than for normal diesel fuel so a more powerful pump is the solution.
usually a heating trace on the fuel line is a good idea especialy in low temperature areas, not too much of a problem here in theUK .Other points to consider are the use of a start up tank with a small amount of diesel in then you can switch to sunflower oil .

A couple of posts raise concerns about sealing rings,
I have never had any problems with this ( so far )however general maintainance is a useful time for changing any of these.

The big advantage bio diesel is that it is renewable

there are some German companies that provide conversion kits
for automobiles

http://www.elsbett.com/

http://www.goatindustries.fsnet.co.uk/

http://www.folkecenter.dk/plant-oil/plant-oil.htm

http://www.oilpress.com/

http://www.geocities.com/vwfatmobile/index.html

there have been stories in the press about farmerrs in Wales depleting the local supermarket of all their cooking oil supplies

http://pub41.bravenet.com/forum/fetch.php?id=9982145&usernum=3470269378

hope all this is of some help

Chris

 

[Herald]

Not too sure on the diesel engines over in the US - but a good recipe for cheap fuel is (as used in my turbo diesel (DI) 2L 4 cyclinder)

1L part diesel (Gas station)
3L parts rapeseed vegatable oil (More power than diesel according to MIT - most other vegetable oil is on a par)
approx 50 ml of Redex (diesel additive - not required in warmer areas - 1:3 (diesel:veg oil only) mix is good to coldstart down to approx -5C).

Ensure the mixture is fully mixed (eg in the cold and pouring veg oil straight in the tank followed by a bit of diesel is NOT going to ensure complete mixing).

The "good" car makes to use are Mercs (seem to run on anything), VW's citroen and peugeot. Ford in Europe us a Lucas fuel injector with composite parts that can die a death. Not sure what is used in US.

Hope that clear things up.

 

[MrBiodiesel]

Well this thread seems to be about dead but I'll post anyway.

As teddy stated earlier, journeytoforever.org is a great site to learn about the basics.

A couple of points though;

Any good biodiesel won't have any methanol in it; therefore it is not miscible with water. Although it is possible to degradation to occur, it generally takes longer than 6 months. And even then there are additives that can be used to extend the shelf life.

Any diesel engine can be run with a blend of up to 20/80 biodiesel/diesel (B20) with no modifications. Newer engines can run at B100 with no modifications and some engine manufactures are starting to extend warranties to cover the use of biodiesel.

The largest warning related to using biodiesel is that it possesses strong solvent properties. When an old vehicle starts to use biodiesel breaks up deposits left by petroleum diesel in the fuel system. This causes frequent changing of the fuel filter until the lines are cleaned out. The benefit, however, is that you’ll be left with a sparkling clean fuel system.

While straight vegetable oil can be burned in a diesel engine there are several problems related to its use. The viscosity vegetable oil is several times higher than that of diesel fuel. This causes flow problems in the fuel system as well as difficulty starting. Using regular vegetable oil also causes thickening of engine oil over time as some VO leaks past seals.

As far as cost goes, the U.S. government is in the process of passing a subsidy on biodiesel that will make it competitive with petroleum diesel. However, this sidesteps the capability of people to make biodiesel in their own backyard for as little as $0.60 per gallon.

If anyone has any questions feel free to ask. It is my name after all

Mr. Biodiesel

 

[Snork]

MrBiodiesel a question.

Subsidies aside, oil shale/tar sands have as a fudamental flaw that it takes more energy to extract a usable product than that product can provide. I've seen studies that show this is true for biodiesel, and others that show its not. This leaves me thinking that its a marginal process and accounting methods can prove it either way by how you allow for equipment operation. Can you provide insite to this? Does biodiesel provide a net gain in energy? And if so, by how much?

 

[amorrison]

Reality check --- Bottom line

ULTIMATELY ULTIMATELY ULTIMATELY --- THE USE OF BIODIESEL MEANS WE ARE USING TOPSOIL TO RUN OUR MECHANICAL ENGINES.

CAN WE (earth life forms) AFFORD THIS ABOMINATION ?

 

[MrBiodiesel]

ScottMC

The problem lies in the broad range of sources that can be used to create biodiesel. One of the primary reasons that the subsidy is needed is due to the feedstock. In the U.S. the most common feedstock for biodiesel is soybean oil, while in Europe it’s rapeseed oil.

The problem is that soy oil is used for much more than biodiesel. This means that any biodiesel that is made from soy has to take oil away from competing industries. As a result the price of soy oil increases, which drives up the cost of the finished biodiesel. There are plants being built now which use waste vegetable oil (WVO) as a feedstock as well as yellow grease, a by-product of animal processing facilities. Unlike soy oil these two feedstocks are classified as waste, and people normally have to pay for disposal. This means that the only cost for raw materials are those caused by transportation of the material to the processing plant.

As far as the energy question, biodiesel produces 33.5 MJ/L while diesel produces 35.5 MJ/L when burned. However, while petroleum diesel has a slightly higher energy density it takes more energy to produce. To get a liter of biodiesel you have to expend 31% of the total energy value of the fuel. But to get a liter of petroleum diesel it takes 120% of the energy value of the fuel, going back to what you said earlier. This is due to the heavy refining that is needed to separate the diesel from crude oil. The cost of petroleum diesel will also increase soon due to the requirement by the EPA that sulfur levels be reduced dramatically.

 

[WGJ]

A question here to MrBiodiesel and a comment to Herald:

Re the degradation of biodiesel - especially the rape seed derived fuel.

"Any good biodiesel won't have any methanol in it; therefore it is not miscible with water"
I an not a chemist, but while I worked on automotive projects concerning 'European' biodiesel, the 'word' was that poor storage of RME (rape methylester) could lead to the growth of organisms in the fuel due to the probable contamination of the fuel by water - this due to an affinity between the fuel and water. The worst product of the degradation was said to be formic acid. What's the bottom line on this?

Re: Engines that it's 'OK' to use biodiesel in

Earlier on in this thread I mentioned my own experiences in developing fuel systems to handle biomass derived fuels in addition to conventional diesels and parafins. Whilst I don't for one minute doubt the experience of others in terms of the ability of certain makes to accept biodiesel as a fuel, there is a certainty - if the 'diesel' vehicle fuel system was not specifically designed to cope with the long term use of biodiesel fuels then you risk some sort of damage somewhere. Fluid seals are the primary risk area as many were specified with nitrile rubber materials which have variable resistance to biodiesel - it depends what grades where specified. Few fuel system products will have had fluoro-elastomer seals specified as these are much ore costly than nitriles and 'ordinary' diesel doesn't need them.
Personally, I wouldn't trust any diesel vehicle fuel system to be 100% compatible with biodiesel unless it was specified and designed after about 1998 at the earliest.

As for Ford vehicles in Europe. There has been a mix of Bosch and Lucas CAV equipment on diesel engines here for some while. Some engines are entirely one equipment, like the 100PS turbocharged York engine in the Transit van, which was all-Lucas.

amorrison4 - what do you mean by 'using topsoil'?
While I am opposed to paying subsidies to european farmers to produce oil seed rape to be put in storage, good farm husbandry does at least keep land in culitvation.

 

[PIGroup]

Thanks to all for the information about biodiesel. I work with a commercial group supporting the use of biofuels & lubes in New York, and above comments summarize the primary issues facing most users. The US gov't is increasing support of biodiesel use as part of an alternative fuels mandate for large federal fleets; most current programs are subsidized by state or local governments in the form of tax benefits. While some hurdles remain, the use of biodiesel seems a more reasonable solution than the options of converting to alternative fueled engines or hybrid vehicles and the infrastructure to fuel them.

Our intention in NY is to promote B-20 (20%biodiesel + 80% petrodiesel), thus introducing biofuel blends to offest the potential application problems and cost. It seems we are very far from biodiesel availability at the retail pump, so most users will tend to be government agencies or fleets who take advantage of tax credits. I understand Europeans are a bit more progressive, but end-users still face the same concerns.

I expect the more corn and soy based products (as well as by-products) we consume, all the better for everyone involved (except amorrison, I guess). The environmental benefits are clear, but the cost, availability & transportation of biodiesel is still in infancy in the US.

I think we'd all be interested to hear from people on this list who have direct experience converting to biofuels.

 

[Chris200]

Having worked on diesel engines for a while, I heard many discussion on this topic. There are a few off-the shelf fixes for some of the problems mentioned in this thread. In addition, the issue of fuel crops is not a simple as it may sound.

Fuel filtering and solidifing: There are heavy truck (i.e. 18-wheelers) fuel filters that include centrifugal prefilters and heaters. These would help solve both of these issues. While it occurs at a lower temperature with diesel, gelling is a common problem that can shut a truck down. As a result, there are many ready to apply ways to deal with this problem. Without going into more options, any heavy truck/engine service shop can sell you this type of stuff.

On the negative side, I don't know what bio-fuel does for emissions. If I remember correctly, ethenol creates formaldehyde in spark ignited engines. In general different fuels create different polution. As the chemistry of a particular tank of bio-diesel may come from a number of crops, it will have different chemistry from the next tank. This will change the exhaust chemistry as well.

The question raised about the use of top-soil as a fuel is a good one. I don't know enough to provide an answer but there are some positive side to this question as well. A considerable amount of farming is done in the world with poor soil conservation practices, especially in third world countries. As these areas develop more efficient practices, perhaps they can supply fuel oil crops. In addition, it seems as if the governments of the more developed world are paying farmers subsidies rather than depending on free-market economics to regulate supply. Perhaps if there was more demand for their crops, the government could step out of using our taxes for this purpose. Farmers stay in business and we get a renewable energy source. Win-Win for all parties. Besides if you ever get hungry, you can put a pot of fuel on your exhaust manifold and deep-fry dinner.

 

[MrBiodiesel]

WGJ:
Sorry about the confusion. While biodiesel and water are not miscible, they are soluble to a very small percent. The polar head groups in the Methyl Ester molecules form reverse micelles with the water, which allows a small percent of water into the solution. This is opposed to BD contaminated with methanol. While also soluble to a very small extent it would help draw water into the solution. The ASTM standard for biodiesel in the U.S. is 0.05% by volume, which is a limit that no decent fuel should have trouble meeting.

While there is no substitute for proper storage of any fuel, especially Biodiesel, there are limits to how long it will stay good. In many cases it will be years if properly stored. In short, there is no strong affinity for water with biodiesel. That’s one reason that it’s safe to water-wash the finished product for purification purposes.

As far as the destruction of fuel by microorganisms, it is possible if the storage conditions are bad enough. While I’ve not heard anything about formic acid production it seems like a viable pathway.

Chris200:
I’m not too sure about frying food with biodiesel. With a flash point of 425°F the food won’t be the only thing getting crispy