Making biodiesel
Biodiesel (also known as Diester) is a substitute for petrol that can be used in directly in most diesel cars. You can buy it in stations in some countries (and pay a shitload of taxes) or make it yourself from waste restaurant oil with a little equipment - and it costs peanuts (but of course, you should check with your local authorities that you are allowed to put the fuel you made yourself in your car). The processes involved in industrial and homemade productions are basically the same, except that in factories they use various techniques to improve output (for instance, they recover excess methanol... but this can also be done in homemade reactors, see http://www.graham-laming.com/bd/ecosystem/state_diagram_new.htm).For now, this page is basically a photo gallery to show it really works - I have nothing substantial to say that is not already on websites like biodieselcommunity.org. Except that unless if operating in pretty warm weather, you really should drain the byproduct before it cools, or all your pipes will end up clogged :-@ I've read that KOH instead of NaOH does not cause that problem, but I have not tested yet.
A small batch
Photos of a small batch made with waste vegetable oil from a large restaurant. The oil was of very good quality (low in FFA, and few food particles). After a couple of hours of decantation |
 After washing and drying, the result is crystal clear :) |
Larger batches
An "appleseed" processor I built, with an big hole at the top to allow easy fitting of the mixing pipes (...and which turned out to be useful to remove all that solidified byproduct). Use only in a ventilated area, and stay away from methanol vapors !