There are at least three ways to run a on biofuel using vegetable oils, animal fats or both. All 3 are used with both fresh and pre-owned oils.
1. Use the oil just as it is-- usually called SVO fuel (straight vegetable oil);
2. Mix it with kerosene (paraffin) or petroleum diesel fuel, or with biodiesel, or mix it with a solvent, or with gas;
3. Convert it to biodiesel.
The first two techniques sound most convenient, but, as so frequently in life, it's not rather that easy.
1. Mixing it
Grease is far more thick (thicker) than either petro-diesel or biodiesel. The function 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 utilizing fossilfuel-- cleaner than a lot of, but still not tidy enough, numerous would say. Still, for every gallon of
grease you use, that's one gallon of fossil-fuel saved, and that much less climate-changing carbon in the environment.
People utilize numerous blends, ranging from 10% grease and 90% petro-diesel to 90% grease and 10% petro-diesel. Some individuals simply use it that way, start up and go, without pre-heating it (that makes veg-oil much thinner), or even 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 difficult and tolerant motor-- it will not like it however you most likely will not kill it. Otherwise, it's not sensible.
To do it effectively you'll need what totals up to an SVO system with fuel pre-heating anyhow, ideally using pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no requirement for the mixes.
Blends with numerous solvents and/or with unleaded gas are "speculative at best", little or absolutely nothing is known about their effects on the combustion characteristics of the fuel or their long-term results on the engine.
Higher viscosity is not the only issue with utilizing grease as fuel. Veg-oil has various chemical properties and combustion attributes from the petroleum diesel fuel for which diesel engines and their fuel systems are created.
Diesel engines are modern machines with really accurate fuel requirements, specifically the more modern-day, cleaner-burning diesels (see The TDI-SVO controversy).
They are difficult however they'll just take so much abuse. There's no warranty of it, however utilizing a mix of up to 20% veg-oil of excellent quality is stated to be safe enough for older diesels, especially in summer season.
Otherwise utilizing veg-oil fuel requires either an expert SVO solution or biodiesel. Mixes and blends are typically a poor compromise. But blends do have an advantage in winter.
As with biodiesel, some kerosene or winterised petro-diesel fuel combined with straight grease decreases the temperature level at which it begins to gel. (See Using biodiesel in winter) More about fuel mixing and blends.