Converting diesel vehicles to run on vegetable oil

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The research that you linked to uses a highly toxic solvent derived from petroleum, hexane. it also uses a lot of ethanol , not that ethanol is so bad. Methanol was shown to be a great fuel back in 1951. yes, you have to use different gaskets etc., but it is not much more dangerous to handle than gasoline, except for the toxicity to the optic nerve. tetraethyllead was far more toxic, and the benzene and MTBE in modern gasoline is certainly not harmless. The main reason that most of the world did not convert to methanol fuel in the sixties was because of the oil lobby. To convert an engine to methanol is about as difficult to do a greaser conversion. Methanol can be made from cellulose, so most of our trash could be converted into fuel. I was part of a research group back in 1986 that was exploring high-pressure fermentations of cellulose to produce methanol. If industry had wanted to make methanol cheaply from renewable sources, it would have been done. If we put the money being wasted on biodiesel into methanol or other reasonable technologies, our trash dumps would be empty and we would burn a supurior fuel.

If methanol combustion forms formaldehyde, so will biodiesel made with methanol, plus all the other nasties that come from biodiesel exhaust that methanol combustion does not contain. the ester is one of the first bonds to break in the combustion of fatty acid esters. There are certainly no emmission advantages to biodiesel. In fact i see no advantages to biodiesel what-so-ever, except by comparison to diesel, a fuel that should have been outlawed decades ago.

Jim

 

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i was not talking about residual methanol, i am speaking of the methylester moities on the biodiesel molecules. they would combust to provide almost identical products. the rest of the molecule tends to form various carbon species. Some of the nanoparticulate carbon produced by diesel and biodiesel is extremely toxic and quite robust in the environment. This area of toxicology is in the early stages, but we now know that very spall particulates can cause serious damage.

The point is that the diesel engine is not a green technology no matter how you dress it up. It will always be far dirtier than the gas turbine or the gasoline-style engines running on light fuels. Plus the whole idea of growing oil-crops to replace fosil fuels is and extremely inefficient and environmentally insane concept.

Energy density is not that much of an issue for personal transportation. It would be simple to redesign an auto to use far less energy, but there is not an economic incentive. Remember planned obsolesense? For example, does anyone really beleave that there is not a better brake technology than rubbing pads on a disc. the reason we have friction brakes is so that they need maintainence. There has not been a technological bottleneck on eficient transportation in my lifetime. The barrier are all political and economic. Profit rules!

BTW, ethanol and methanol have almost identical solvent properties. methanol has a higher resistance to knocking (octane number of about 120 as opposed to 112 or so for ethanol), making it a better fuel for high-compression engines. Ethanol is far less toxic however and is certainly a wonderful fuel. The only real drawback to alcohol as a fuel is lubricity, they have none.

I think the research money and publicity campains for biodiesel are pushed by the trucking lobby and the petroleum industry. It is a diversion tactic that has no hope of substantial improving any metric of success in our global transportation mess. This whole biodiesel craze is either woefully misguided, or intentfull in slowing the progress of any kind of real energy reform.

kinda cool hobby, gotta admit. If i were catering festivals again, i would drive greaser for advetising sake.

Jim

 

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This has been a most informative thread, thank you guys for providing the insights, I see I've been over-simplifying biodiesel technology as a feasible alternative to gas, as Jim's "devil's advocacy" suggests. I hadn't seen it from that angle (plus, coming from an engineering background myself, I dig this "green" technology shit)...

However, I'm still not convinced that it's nothing more than a mom and pop hobbie, I mean farmers have been using the stuff for years in their equipment, no conversion needs to be done to my VW TDIs (which, incidently burn quite efficiently and cleanly due to the high temperatures the turbo produces), and land is an under-utilised resource in this country (unlike countries in Europe, in which the production of biodiesel is becoming a problem due to the lack of land area). My understanding is that American farmers are actually being subsidized NOT to grow corn, the primary ingredient in biodiesel. Meanwhile we're over in Iraq spending billions to get our youth killed, and nothing is coming from it, plus all around me I'm seeing strip malls and WalMarts being built on rich agricultural soil, so something's definitely wrong with this picture. I agree it's a political problem. Perhaps if we could channel some of our resources into biodiesel and other alternatives besides petroleum, we might get somewhere...but large-scale changes take time...

 

Mellow Yellow and Shaggie,

I have overstated the "hobby" bit. I agree that there is a niche market for biodiesel and a useful part that it can play in this transition period. However, making the stuff is quite hazardous to your health unless you have sophisticated equipment, the popular idea that biodiesel is a reasonable solution to global transportation energy issues. If i was a farmer, i would make ethanol like crazy and compost manure for methane. The last time i checked, there were great tax credits for making ethanol as a fuel.

Oil crops are horrible uses for land. Is vast monoculture that much better than walmarts? OK, maybe a bit, but we are not talking about stable ecosystems. Such farming is environmentally unsound. Hemp would probably be the best oil crop, but how likely is that?

Those of you out there who want to work with methanol, please understand what you are dealing with! Biodiesel is a dangerous choice for a garage project, from the toxicity standpoint. Ethanol production is far safer and more fun.

Jim

 

Point taken, Jim. One of the most stressed points that is made in this book I bought on how to make biodiesel is the toxicity of some of the materials. But there are other options. For one, there are biodiesel coops throughout the country that (presumeably) make it in large scale vessels that are contained and (PRESUMEABLY) safe for the workers who make it. Unfortunately, the stuff is more expensive than conventional diesel, but that may not be the case if conventional diesel goes up in price. Furthermore, there is a kit available through the biodieselamerica websight that does all the measuring and mixing for you, so minimal handling is required. The biodiesel costs about 1.50/gallon to make, based on the assumption that the oil is free, but the kit costs like 3-4 grand for the top of the line one that requires no handling of the toxins, so you're gonna be making a lot of biodiesel before it pays for itself. I must admit that I was somewhat skeptical at the thought of making it myself, and now I'm a bit more skeptical, but it's good to know that these alternative options exist.

 

The reaction is simple, but properly containig the methanol fumes is not a cheap proposition. I think you will find that most of the coops, are not handling the methanol in an entirely appropriate manner. Respirator masks are poor replacement for proper volatile recovery equipment.

Ethanol can be an enjoyable and lucrative home project. I would love to hear about emulsions of waste oil and ethanol. In the right ratio, with the right surfactant, that mix might be a reasonable diesel or gasoline replacement option for home production.

Just a crazy idea we have been kicking around.

 

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