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

 

[WGJ]

Chris200 - Good luck in NY with this particular alternate fuel. I personally think that it has a lot going for it in terms of 'the big picture'. If you can at least get bus fleets and garbage trucks, etc. to use such fuels there is a global environmental plus.
Someone else mentioned the recycling of fats and oils used in the food industries - these will reprocess as a diesel engine fuel, albeit at some cost but it is still an environmental plus. In cities there has to be a lot of this sort of waste material about.

As for western argriculture subsidising the oil crops - I live in the county of Essex in the UK - it's the one east of London and on the north bank of the Thames estuary. Until 50 years ago, it was almost a completely rural economy and, by and large, you can grow just about anything here.
Unfortunately, and mostly as a result of the UK being in the European Economic Community, a lot of lunatic subsidies, originally designed for continental small-scale farms, encourage the growing of crops like rape, for which the market is much smaller than the output. Hence we get surplus rape seed oil stored, at government (ie taxpayer's) expense all over the EU. It looks fine from a distance in May, when the fields around here are almost alight with the brilliant yellow of the flower. However, the urine-like stink which accompanies the flowering period is much less welcome.
As for the quality of land required to support cultivation, the rich farmland around here is effectively wasted growing this stuff. Obviously, the 'crop' from this plant is not the stalk or the leaf, but the seeds which follow the flower. As a result of needing to get the seeds set and ripened before the combines move in to harvest, many of the plants will have set their seeds or birds will have taken them. What follows is that a wild crop of the rape plant begins to develop along roadsides, on pieces of uncultivated land and on the central reservation of dual carriageways (you call it the median?) as a result of the distribution of the seed.
In some areas, local authorities have been forced to weed out the plants as they have a tendency to take over.
On this basis, I reckon they'd grow anywhere with a temperate or temperate to dry climate, without much encouragement, and the stalk and leaf residues could be composted to act as a soil conditioner/enricher for other crops. A possible boot-strapping process in some countries.
In case anyone doesn't know, they're a member of the cabbage family.

 

[benski9151]

I personnally use waste vegetable oil (WVO) that I pre-filter in my garage and pour into a coolant hose heated 2nd tank in the trunk. I use hose in hose (wvo surrounded by cooland) to carry my new "fuel" to the injection pump.

Again, once the engine is hot (started from cold on petro-diesel), I switch using an electro-mechanical 6 port fuel selector valve to 100% recycled veg oil.

So yes, my VW Jetta 1996, IDI, works real nice on straight veg oil. Runs smoother, with very slight reduced power (maybe 5%). A frind of mine has 55 000 km ran on WVO in a 2000 VW Jetta TDI with no problem at all, even in the cold winters of Eastern Canada.

Hope this will help.

Another good reference would be here:

http://biodiesel.infopop.cc/eve/ubb.x

Bye,

 

[CCycle]

Since this thread has been resurrected I am going to jump in for at least one comment and a question.

Vegetable oil and/or ethanol can not be produced in enough quantity and at a low enough cost to replace petroleum based fuel. Granted we should recycle all waste oil in preference to dumping or land filling but this is a low percentage of the fuel needed.

The oil part of a crop is low, usually 10% or less by weight. It probably will not supply the fuel necessary to grow and process the vegetable crop into fuel.

It seems like an engine could be designed to burn finely divided starch and cellulose directly. This way a 100% of the crop could be used as fuel. Engines have been run, all be it imperfectly, on coal dust. And some very large stationary engines burn residual oil. These turn very slow which gives the residence time necessary to burn the large molecule (carbon number 20 and up). It seems like a high temperature CI engine such as a ported two cycle (no valves) with insulated piston and head could develop enough heat to burn vegetable material directly.

Granted such an engine would produce copious amounts of NOx. But could not we learn to use this? Agriculture needs large amounts of fixed nitrogen. NO2 is the precursor used to produce nitrate plant fertilizer. The NO fraction can be quite conveniently oxidized to NO2.

It is not generaly realized but the industrial revolution is suppling the additional CO2 nessary to feed the high popoulation now on the earth. It may be that the internal combustion engine is inadvertertly adding to the fixed nitrogen base too.

 

[REDMANE]

I have made biodiesel using a 2 part acid (esterfication), base (transesterfication) process with good result. I use 100% waste cooking oil (as I live in Southern Louisiana, here they deep fry everything)in this process. As a cooking by product the feedstock must be dewatered and solids and insatiables must be filtered and or settled out.

the processor uses a Heliostat to provide process heat and has a vaccume methanol recovery system that recovers 30% to 40% of the uncatalyzed methanol feed stock.

This processor produces 60 US gallons of biodiesel and 25 to 30 gallons of glycerin from 100 gallons of feedstock per week. The used oil is a freebie and the reactants (methanol, 99% lye (sodium hydroxide) and 95% sulfuric acid cost about $20 to $30 USD.

the processor started out as a experiment to test the feasibility of using biodiesel as an additional fuel source in my 1999 dodge pickup. We now use the home brewed biofuel exclusively the dodge runs like new with slightly more power and cleaner emissions (retarded the injection timing to reduce combustion temps in an effort to reduce N0 formation) on fuel that was made from waste a waste that would still need some sort of processing to before disposal.

The process is a catalyst reaction and takes very little energy in put aside from pumping and heating (solar) to 140 degrees F fro dewatering and glycerin separation. The initial energy cost in growing, harvesting and extracting the WVO is of little concern as the use it was initially produced for it has fulfilled and at the point I acquire the used oil it is considered waste and would cost the initial user money in its disposal.
Also, have built a system to process the by product glycerin to about 95% purity product for sale to the cottage cosmetic and soap industry.

As for elastomerics (pardon my spelling as I graduated from public school in LA) in the Cummins engine, the engine is as liquid tight as the day I bought the truck.

At the present cost of #2 diesel ($2+) I save $1 to $1.25 a gallon. And the trucks exhaust has a slight French fry aroma!

 

[liberty]

Hi REDMANE that is awesome. Can I ask a few questions?

The truck doesn't need to warm up on $2 diesel before switching over to your biodiesel, even on cold days?

No modifications to the fuel lines (new seals)?

How often do you change the oil?

The processor sounds like an expensive setup. You should sell your plans in the back of Popular Mechanics or something, but include a few words on liability protection before Joe Shmoe is handling 95%+ pure acid & base. Ouch!

 

[REDMANE]

No Pre-running on petro-diesel even on cold days bio-diesel made from nut oils and/or animal fats have a solidification issue. However, I live in the southern US and a cold day here is in the 20s to 30s Deg F most of my feed stock is peanut and safflower oil . Almost all diesel engines produced since 1995 have ester resistant elastomerics, including fuel lines, primary (lip seals) and secondary sealing elements (sealing rings and gaskets).

Contrary to popular belief, I change oil at the rated medium duty interval of 7000 Miles. Also twice a year I have an oil analysis done to check engine wear.

The processor is more or less a collection of three cone-bottomed tanks and a homemade inline sock filter. One small sliding vane PD pump (to allow tank stripping) and some piping; The chemicals are used in small amounts the acid for example is about 5% by volume and is added from a acid resistant carboy with a manual control valve to adjust addition rate. One tank for dewatering, the second for reaction and a third for washing and neutralization, all tanks are in process simultaneously the finished product goes to a 300 gal. fuel tank and is tripled filtered before it goes in a vehicle.

The Heliostat is a couple or sheet of reflective aluminum sheeting formed into a parabolic trough with a carbon steel tube at it reflection apex, covered with cheap window glass.
it is aimed to the south and uses a clock motor and a shaded photocell for tracking.

I am a handy person and I did all the fabrication.

The piping is cpvc Sch 80 good to 212 F and is acid and base resistant. The PH almost never strays more then to points from neutral.

As for selling the plans there is a plethora of plans out there, mine is an adaptation of the better parts of many with a few addition of my own ideas. Most people unless driven to understand the esoteric would not go to such lengths.

Anthony Milford (Redmane)

 

[Bytesmiths]

I'm burning biodiesel in two vehicles (1985 Jetta and 1989 Cummins) and Waste Vegetable Oil (WVO) directly in Veggie Van Gogh.

There are some common misconceptions in this thread to date:

There are three ways to use vegetable oil in a common diesel engine, all of which have the common goal of making the vegoil thinner:

1) Chemical (biodiesel): trans-esterfication separates the hydrocarbon chains from the glycerin via the introduction of alcohol in the presense of a catalyst. The most common process uses methanol, but ethanol can also be used, albeit in a more complicated process.

2) Dilution: some people simply mix diesel fuel or gasoline or mineral spirits or whatever with vegetable oil. IMHO, this is the most risky way of doing it -- both to the engine, and for safety.

3) Heat: using engine waste heat and/or electric heat, vegetable oil becomes as thin as cold diesel fuel. This requires about 80 degrees C, or 180 F. A combination of coolant heat and electric heat is often used. See my site posted above for design notes and schematics on this process.

The critical item for any of these is the injection pump. Bosche is well regarded in vegoil circles, while Lucas is almost universally despised.

Other than that, damage due to biodiesel is rare and limited. After several years of use of commercial, washed biodiesel, rubber fuel lines may swell or weep and need replacing. I replaced the 1989 lift pump (NOT the expensive injection pump) on Veggie Van Gogh with one with a Viton diaphram for about $70, and am still using the original rubber fuel lines, two years later, with no obvious damage.

The point about using cropland for fuel production is well taken. However, we are currently growing food with a heavy input of non-sustainable petroleum, at approximately 2-4 calories of petroleum for every calorie of food produced! When that oil goes into decline within the decade, we'd better have something else in the pipes!

Soy is used for most commercial biodiesel production today, but it is a very inefficient source. This probably has more to do with farm state subsidies than anything else. Rapeseed produces over twice as much oil per hectare. Tropical oils can produce nearly ten times as much oil as soy. Small test plots of algae suggest it may produce as much as 500 times as much as soy, but it is not a mainstream product, and there are lots of bugs to work out.

Biofuels are widely derided as incapable of supplanting the entire petroleum fuel stream. This is true, but that doesn't mean they shouldn't be used. No single proposal is currently capable of replacing petroleum. The ideal future hold a distributed, diverse energy structure, versus the "energy monoculture" we have today.

The current US waste vegoil stream is about 3 billion gallons per year, or about 10% of the US diesel fuel consumption, or about 1% of the US gasoline consumption.

In short, making biodiesel or using vegoil directly works well and is easily within the capabilities of a home handyman tinkerer.

 

[turbolader3000]

Yes. At this time rapeseed can only supplement petro-diesel. In Germany diesel is mixed up to 5% with biodiesel. That doesn't affect the endurance of diesel engines, especially rubber parts (ok, maybe in an old Mercedes Benz from the 70's)

One can't simply burn down petroleum, it has to be replaced by other kinds of fuel because petroleum is needed for other purposes (e.g. chemistry)...

 

[GregLocock]

Now there's some logic I find hard to understand. Why is biohydrocarbon not suitable as a feedstock for chemical industries, but OK as a fuel? I'd a thunk they were pretty much interchangeable.



Cheers

Greg Locock

 

[aeliot]

Greg -
biofeedstocks are quite different chemically from the hydrocarbon components of petroleum (for more detail, see below). The short answer is that if you're burning it for energy, the exact chemical structure isnt all that relevant as long as other properties (boiling point, flashpoint, viscosity, etc) are acceptably close. So in engines, methylesters of fatty acids (derived from vegetable oils) are a pretty good mimic of heavier petroleum fractions like diesel fuel and ethanol (produced by bulk fermentation of sugars) is similar to lighter petroleum fractions like gasoline.
For the chemical industry, however, the chemical structure of the starting material is crucial, and the starting materials like ethylene and propylene arent biological molecules, so you have to create an entirely new process to get your product from available biological feedstocks.
In more detail, biofeedstocks can grossly be divided in 4 categories--oils (ie long chain fatty acids and the glycerol esters thereof), sugars (primarily glucose and related polymers like starch, cellulose, hemicellulose, etc), protein/amino acids, and heterogeneous organic mixtures like animal waste. Note that none of these are hydrocarbons--all are at least partially oxidized, so they cant be cracked and refined to yield the same products as petroleum.
From these, it's really easy to make common fermentation products like ethanol and acetic acid using large scale bacterial cultures. Other biological molecules like amino acids (eg MSG) and vitamins and such are also fairly easy to make using modified bacterial strains that overproduce specific compounds. However, production of industrial chemicals requires development of new pathways to products from these feedstocks. For most industrial chemicals, the cost of developing processses using biofeedstocks if such a process is possible at all is too high to make it feasible when compared to use of petroleum.

 

[Bytesmiths]

In addition to aeliot's excellent posting, it should be noted that a property that makes biofuels an excellent combustion fuel also makes them a poor feedstock for organic chemistry: lack of cycles.

This means they don't put cancer-causing PAHs into the atmosphere when they burn, but it also means you can't make all the neat stuff that you can from benzene.

A "real" chemist should feel free to step in here...

 

[aeliot]

an addendum to my previous post: it was pointed out to me that hydrocarbon fuels are accessible from biomass using gasification to a syn gas-like product (ie mostly H2 and CO and some other gaseous hydrocarbons). This "bio syn gas" can then be polymerized using a Fischer Tropsch process to give very high cetane diesel fuel that is in many ways higher quality than petro diesel--no sulfur, no BTX. The result is lower emissions, but without many of the problems of traditional biodiesel. I think cost is still is big obstacle right now, but technology is improving.

 

[rmw]

The Fisher Tropsch process can utilize any hydrocarbon, from turkey guts to waste wood to natural gas. Google "gas to liquids" or "fisher tropsch" or "gtl" for an interesting read about plants in Quatar and other gas rich places with plants about to come on line within the next few years.

rmw

 

[Northboundtrain]

This has been an excellent thread. I've been involved with biodiesel for a few years now, and I've never seen so much pertainent info. in one place.

It has always seemed to me that if vegetable oil is to gain widespread use in diesel engines, then it is the engine, not the oil, that will need to be modified. Making biodiesel seems like a great way to use vegetable oil for fuel in the immediate short term. But in the long term and on the large scale, why go through such an involved and expensive industrial process if an engine (and fuel system) could be developed that would burn vegetable oil directly?

I would think that the gelling problem and the necessity to preheat the fuel could be easily addressed in a fuel system designed specifically for vegetable oil as opposed to petro diesel.

The main problem, as I understand it, is that vegetable oil has a tendency to polymerize when heated. This polymerization occurs when the oil is placed under high pressure prior to injection. Injector tips can become fouled, cylinder walls wear faster, and injection pumps can be damaged by the polymerized particles that come back through it via the return fuel line.

Many people have successfully run vehicles on straight vegetable oil. However, I have also heard of several failures related to the above issue after roughtly 10k-30k miles. I have never heard of anyone successfully running a diesel engine on straight vegetable oil for the expected lifetime of the engine, i.e., 200k-300k miles.

I am currently rebuilding an engine for an '81 VW Rabbit that I will run on straight vegetable oil if I can address the issue of polymerization.

Does anyone know of potential solutions to this problem?

 

[Bytesmiths]

Northboundtrain wrote: "I have never heard of anyone successfully running a diesel engine on straight vegetable oil for the expected lifetime of the engine, i.e., 200k-300k miles..."

You might want to check out the vegoil-diesel Yahoo Group. There are people on this list who have in excess of 100,000 miles on vegoil. There's even an owner-operator trucker who routinely goes coast-to-coast on it, and I believe he was claiming half a million miles!

On the other hand, there are horror stories, such as the band called Ape.

Bottom line seems to be that careful people who do their homework can have great results.

I've only got about 5,000 miles on mine, but I'm hoping for hundreds of thousands more!

 

[WGJ]

May I echo Northboundtrain's comment about this thread being excellent?

There is certainly a good amount of knowledge shown on the use of biofuel and waste cooking oil in engines.

I used to work in the UK in fuel delivery engineering for a major US auto manufacturer. Some ten years ago my colleagues and I had recognised that such fuels might take a reasonable slice of the auto fuels market, especially in economies that imported all their fuels. We also saw that biomass blended with normal diesel was likely to grow as alcohol/gasoline blends have.

However, it proved very difficult to get this across to the management of the company and to procure enough cash to fund a worthwhile programme to examine the long term effects of the use of blends and 100% biofuels. In fact, one of the company's 'experts' from the USA produced a graph showing a decreasing trend in the use of diesel engines which was almost the exact reverse of what our own independent market research indicated.

Suffice it to say, the cash soon ran out when our own UK management decided not to push the case for funding.

What we did see:
- The more recent your fuel system, the higher the temperature of the fuel going back to the tank. Experience with systems using the Bosch VP44 pump showed that at ambient temperatures of 38ºC, temperatures at the FI pump could exceed 90ºC under load and given time, the bulk fuel store in the tank would rise also and the fuel at the pick-up might approach 90ºC as well - this was with a simple fuel delivery module in the fuel tank. Vehicles tested were 4cyl units of 1.8 to 2.5 litre IDI turbocharged (about 100hp)

This was bad on two accounts:
(1) The durability of the FI pump was affected. Metallurgical failures of the high pressure pump components were experienced with fuel temperatures like this. The Bosch VP44's used in development also had some keep-alive memory which allowed their recent history to be examined in the event of a failure. If this feature persisted into production this is obviously a problem for anyone that has a VP44 failure in warranty as the manufacturer can refuse to cough up if the part had been 'misused'. For anyone with an older vehicle this is a costly failure. I imagine that a 100% bio fuel with no sulphur content wouldn't help this.

(2) Where the vehicle had a plastic (HDPE) fuel tank, certain tank manufacturers voiced concern over the performance of the tank, long term. One manufacturer said that their biofuel tests had shown that tanks could blister following long term exposure to hot biofuels - I never saw this myself but this was a major tank supplier that we had no commercial ties with.

- Seals and gaskets
This was mentioned much earlier in the thread, however, there are still many places in the fuel supply system where you may find nitrile rubber seals and these seem to be the ones least able to deal with biodiesels. For example:

Fuel line 'quick connects' tend to have two 'O' rings these days, one nitrile and one viton. The nitrile stays relatively flexible at low temperatures when the viton gets hard and the viton provides some durability as the nitrile ages.
Fuel sender/fuel module gaskets are usually nitrile and the bung where the fuel filler pipe joins the tank is often nitrile when the filler pipe is a separate part. All these parts were seen to degrade when high fractions of bio were used in diesel fuel.

-Fuel lift pumps.
Specifically where electric pumps are used and where they are the 'in-tank' type similar to gas EFI pumps. Bosch were the only people that I found that had a grasp of the durability issues associated with bio. Benerally, the pump's mechanical components lasted really well, as you might expect. The real problem area was brush and commutator wear.
Some pumps we used were showing a brush/comm life of about 30% of that of similar gas EFI units. Brushes wore quickly and also wore deep tracks into the commutators. The composition of the brush was the major factor and to a much, much lesser extent the material and shape of the commutator.

Sorry tis is a bit long - last item.
My local domestic recycling yard has a place for just about everything except waste cooking oils and fats. There is a tank for engine oil but not for anything else. perhaps it's time the recycling of this particular domestic waste was begun.

 

[Bytesmiths]

I'm currently going through the exercise of pre-emptively replacing fuel lines in Veggie Van Gogh. I pulled the fuel lines, and they look to be in good shape, but I had to drop the tank anyway, so I'd rather do this at a time of my choosing than along the side of the road somewhere!

Viton is HORRIBLY EXPENSIVE! I need 34 feet of 3/8" hose -- that's nearly $700 worth of Viton!

With some additional research, I found that most fluoroastamers will tolerate both biodiesel and vegoil quite nicely. The problem is they are generally semi-rigid materials. Nylon 6 and aluminum are also okay -- copper-bearing metals (brass, bronze) or zinc or lead bearing metals (galvanized, soldered) are out.

So I got 50 feet of clear Teflon 3/8" OD semi-rigid tubing for $150, which I am planning to join to the existing barbs with SHORT lengths of 3/8" ID Viton.

The Teflon is not as abrasion resistant as the old rubber (probably Nitrile) hose, so I'm going to cover it with 1/2" electrical loom, and of course, secure it to the chassis properly.

 

[WGJ]

I hope you don't mind me saying, but keep at it, Bytesmiths!
DIYers seem to make more fundamental progress on stuff like this than the big boys.
I can't recall having any problems with nylon6/66 material fuel lines, by the way.

On the BBC News this morning there was an item about global warming, apparently some research is suggesting that when the average global temperature has increased by 2C° the condition may bevome non-reversible. Currently the figure is 0.8C° - these figures are as compared to pre-industrialisation figures of c1750.
The USA was described as currently contributing 25% of the world's CO2 for just 4% of the world's population, so any move to biomass-derived fuels must be a good one. Rather recirculate CO2 than make more from fossil fuels.

Coventional diesel fuel technology in Europe for cars and light vans is now centred firmly on common-rail systems with injection pressures in the range 800 bar at idle to 1600+ bar at load. The whole fuel injection regime is 3D mapped just as a gas EFI system is. This results in average fuel consumption figures of 40 miles per US gallon for a Contour/Mystique sized vehicle at Euro Stage III emissions levels. Stage IV is imminent.
It would be nice to see power and emissions results from systems like this run on biomass or waste veg oil fuels. I dare say someone has done this, but I am no longer closely enough associated with this work to be kept informed.

More power to you.

 

[GregLocock]

"On the BBC News this morning there was an item about global warming, apparently some research is suggesting that when the average global temperature has increased by 2C° the condition may bevome non-reversible. "

Oh, so if the average global temperature has ever been more then 2 degrees higher than it is now then the current world could not exist.

So how hot, exactly, do you think it has /ever/ been in the past?

http://www.edu.pe.ca/morellhigh/grassroots/global/history.htm

"Global warming is always assumed as being a bad thing, but it has existed as long as 75,000,000 years ago. From the heterotroph hypothesis founded by a man by the name of A.I. Oparin we know that prehistoric earth had an atmosphere which was densely polluted by Carbon Dioxide, Methane, Nitrous Oxide, Hydrogen gas, and Water vapor. It was the existence of these gases and the violent natural reactions that resulted in an average temperature that was about 5.6 C higher than today."

So, either the BBC report is wrong, or Oparin's work is wrong. I'm guessing the Beeb report is alarmist nonsense.







Cheers

Greg Locock

 

[WGJ]

Sorry to have apparently offended - I noted this morning's report, that's all. The BBC reported what had been published. I don't think they normally engage in alarmist reporting techniques themselves.

I also appreciate that the examination of the world's past shows conditions that were incredibly different from those we enjoy today, and I think that's what reports like this are about.
Ice ages and periods of tropical warmth in northern latitudes have come and gone many times, there is no doubt. Evidence suggests that the changes in the past took hundreds, if not thousands or tens of thousands of years and evolution adapted.
However, what we are apparently looking at is whether flesh and blood like you or I could cope with unnaturally rapid change and whether the world could continue to feed itself.