Make your own biodiesel: Journey to Forever Part 1

Make your own biodiesel: Journey to Forever
Detailed description of methods of creating biodiesel and its related issues.

Click Here to Make $20-$75/Hour for Your Opinion

Three choices
There are at least three ways to run a diesel engine on biofuel using vegetable oils, animal fats or both. All three are used with both fresh and used oils.

Use the oil just as it is -- usually called SVO fuel (straight vegetable oil);
Mix it with kerosene (paraffin) or petroleum diesel fuel, or with biodiesel, or blend it with a solvent, or with gasoline;
Convert it to biodiesel.
The first two methods sound easiest, but, as so often in life, it's not quite that simple.

1. Mixing it
Vegetable oil is much more viscous (thicker) than either petro-diesel or biodiesel. The purpose of mixing it or blending it with other fuels is to lower the viscosity to make it thinner so that it flows more freely through the fuel system into the combustion chamber.

If you're mixing veg-oil with petroleum diesel or kerosene (same as #1 diesel) you're still using fossil-fuel -- cleaner than most, but still not clean enough, many would say. Still, for every gallon of vegetable oil you use, that's one gallon of fossil-fuel saved, and that much less climate-changing carbon in the atmosphere.

People use various mixes, ranging from 10% vegetable oil and 90% petro-diesel to 90% vegetable oil and 10% petro-diesel. Some people just use it that way, start up and go, without pre-heating it (which makes veg-oil much thinner), or even use pure vegetable oil without pre-heating it, which would make it much thinner.

You might get away with it with an older Mercedes 5-cylinder IDI diesel, which is a very tough and tolerant motor -- it won't like it but you probably won't kill it. Otherwise, it's not wise.

To do it properly you'll need what amounts to an SVO system with fuel pre-heating anyway, preferably using pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no need for the mixes.

Blends with various solvents and/or with unleaded gasoline are "experimental at best", little or nothing is known about their effects on the combustion characteristics of the fuel or their long-term effects on the engine.

Higher viscosity is not the only problem with using vegetable oil as fuel. Veg-oil has different chemical properties and combustion characteristics from the petroleum diesel fuel for which diesel engines and their fuel systems are designed. Diesel engines are high-tech machines with very precise fuel requirements, especially the more modern, cleaner-burning diesels (see The TDI-SVO controversy). They're tough but they'll only take so much abuse.

There's no guarantee of it, but using a blend of up to 20% veg-oil of good quality is said to be safe enough for older diesels, especially in summer. Otherwise using veg-oil fuel needs either a professional SVO solution or biodiesel.

Mixes and blends are generally a poor compromise. But mixes do have an advantage in cold weather. As with biodiesel, some kerosene or winterised petro-diesel fuel mixed with straight vegetable oil lowers the temperature at which it starts to gel. (See Using biodiesel in winter)

More about fuel mixing and blends.

2. Straight vegetable oil
Straight vegetable oil fuel (SVO) systems can be a clean, effective and economical option.

Unlike biodiesel, with SVO you have to modify the engine. The best way is to fit a professional single-tank SVO system with replacement injectors and glowplugs optimised for veg-oil, as well as fuel heating. With the German Elsbett single-tank SVO system for instance you can use petro-diesel, biodiesel or SVO, in any combination. Just start up and go, stop and switch off, like any other car. Journey to Forever's Toyota TownAce van uses an Elsbett single-tank system. More

There are also two-tank SVO systems which pre-heat the oil to make it thinner. You have to start the engine on ordinary petroleum diesel or biodiesel in one tank and then switch to SVO in the other tank when the veg-oil is hot enough, and switch back to petro- or biodiesel before you stop the engine, or you'll coke up the injectors.

More information on straight vegetable oil systems here.

3. Biodiesel or SVO?
Biodiesel has some clear advantages over SVO: it works in any diesel, without any conversion or modifications to the engine or the fuel system -- just put it in and go. It also has better cold-weather properties than SVO (but not as good as petro-diesel -- see Using biodiesel in winter). Unlike SVO, it's backed by many long-term tests in many countries, including millions of miles on the road.

Biodiesel is a clean, safe, ready-to-use, alternative fuel, whereas it's fair to say that many SVO systems are still experimental and need further development.

On the other hand, biodiesel can be more expensive, depending how much you make, what you make it from and whether you're comparing it with new oil or used oil (and depending on where you live). And unlike SVO, it has to be processed first.

But the large and rapidly growing worldwide band of homebrewers don't mind -- they make a supply every week or once a month and soon get used to it. Many have been doing it for years.

Anyway you have to process SVO too, especially WVO (waste vegetable oil, used, cooked), which many people with SVO systems use because it's cheap or free for the taking. With WVO food particles and impurities and water must be removed, and it probably should be deacidified too.

Biodieselers say, "If I'm going to have to do all that I might as well make biodiesel instead." But SVO types scoff at that -- it's much less processing than making biodiesel, they say.

To each his own.

Click Here to Make $20-$75/Hour for Your Opinion