That gives me some questions.
For instance, how do you, at best, filter the frying oil. What kind of method and materials?
Then it's mixing. I'd not get enough to run pure, so what kind of a "coktail" would suit?
In winter, for instance, the normal diesel we get does not always work. They're running with just one sort over the year (before it was one special for winter), and it gets to thick, so you use some specials (which are expensive) or just mix with mineral oil (which costs about the same as diesel). The mineral oil dries out a little bit too much the lube quality (needed for the oil feeding system) so you add either just some engine oil (like 0,5%) or what is told to be better, - two-stroke oil, 2%. So welcome to the world of cocktails, and the difference this does for me is simply an engine running instead of...not.
My testbed would be a Perkins engine, 3 cyl, 47 hp, no complex system, just a simple engine. Design is from about 1965-1970. Secondary would be a Czech Zetor, also 3 cyl, 47 hp. Eastern block of old design.
Ahh, and the benefit. My countrymen haven't caught up with this, and most of those who would want this run modern engines and do not take risks. The fuel is up for grabs, and probably completely free of charge. That does make a bit, when you use 10 gallons a day, and the gallon costs you $4 off the pump.