Make your own Biodiesel Part 1
There are at least 3 methods to run a diesel motor on biofuel utilizing veggie oils, animal fats or both. All three are used with both fresh and used oils.
1. Use the oil just as it is-- normally called SVO fuel (straight grease);
2. Mix it with kerosene (paraffin) or petroleum diesel fuel, or with biodiesel, or mix it with a solvent, or with gasoline;
3. Convert it to biodiesel.
The first two methods sound most convenient, but, as so typically in life, it's not quite that simple.
1. Mixing it
Grease is much more thick (thicker) than either petro-diesel or biodiesel. The purpose of blending it or blending it with other fuels is to reduce the viscosity to make it thinner so that it streams more freely through the fuel system into the combustion chamber.
If you're mixing veg-oil with petroleum diesel or kerosene (like # 1 diesel) you're still using fossilfuel-- cleaner than many, but still unclean enough, many would state. Still, for every gallon of
vegetable oil you use, that's one gallon of fossil-fuel conserved, which much less climate-changing carbon in the atmosphere.
People use numerous mixes, ranging from 10% grease and 90% petro-diesel to 90% veggie oil and 10% petro-diesel. Some people simply use it that way, launch and go, without pre-heating it (that makes veg-oil much thinner), or perhaps use pure grease 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 will not like it but you probably won't kill it. Otherwise, it's not sensible.
To do it effectively you'll require what amounts to an SVO system with fuel pre-heating anyway, ideally 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 gas are "experimental at best", little or nothing is learnt about their effects on the combustion characteristics of the fuel or their long-lasting impacts on the engine.
Higher viscosity is not the only problem with using grease as fuel. Veg-oil has various chemical residential or commercial properties and combustion attributes from the petroleum diesel fuel for which diesel motor and their fuel systems are developed.
Diesel engines are high-tech makers with very fuel requirements, especially the more modern, cleaner-burning diesels (see The TDI-SVO controversy).
They're hard however they'll just take so much abuse. There's no warranty of it, but utilizing a blend of up to 20% veg-oil of excellent quality is stated to be safe enough for older diesels, particularly in summer season.
Otherwise utilizing veg-oil fuel needs either an expert SVO solution or biodiesel. Mixes and blends are normally a bad compromise. But mixes do have a benefit in cold weather.
Just like biodiesel, some kerosene or winterised petro-diesel fuel combined with straight veggie oil decreases the temperature at which it begins to gel. (See Using biodiesel in winter season) More about fuel blending and blends.