the only really difficult part is makeing sure your chemistry is correct with the methanol/lye mix. reason for the heater elements is to make the veggy oil flow faster, easier on the pump and lets it go through the filters faster. speeds up the chemical reaction as well. go higher than 140F and you start running the risk of fire with the methanol when its in the tank, that would be really ugly. 120F works as well, above 160F is when the fire can happen. what gets you with cost is all the little stuff adds up. 15 dollar valve here, another there, etc it adds up to about $300 for the usual cost. i got my waterheater and a metal scrap yard for 20 bucks, if you use an old water heater those elements can be a pain in the ass to unscrew so be forewarned.
full hands on time once the processor is made, about 40 minutes your 1st few batches and about 20-25 minutes once you've got your rythem down. flip a switch, turn a few valves, then plug in the pump. come back in 30-45 minutes, turn it off, unplug the pump and close the valves and let it sit again. the titration testing sounds alot more difficult than it is but make sure to wear the gloves/apron and a face shield or at least glasses wouldnt be a bad idea. lye will give you bad chemical burns, keep some vinegar nearby when your dealing with it for just in case (neutralizes it).
the processor i made was basic. you can get fancy and add a fuel drying station as well but i didnt run that. what a drying station does is it lets the biodiesel sit for a little while so any water thats left can settle out. water is your enemy with using used veggy oil, more water mixed with the veggy oil the more you have to remove. can boil the water out if its a small enough batch, but the obvious risk there to me was not worth it. running it through the filters/water seperator setup a couple more times before i put it in the tank made it easier and i never had any issues driving. i let the biodiesel (after i'd already gotten the soap and glycerine out of the water heater) cycle through the filter setup for about 30 minutes before i would pump it into my fuel tank.
you can also do a methanol recovery setup to cut your cost even further, basicly you boil it out of the glycerine and recover roughly 50% of the methanol to use again later. my cost before the methanol recovery, usually 85 cents a gallon was my average. with the cost of methanol and lye up your looking at about a dollar a gallon right now. with the methanol recovery my cheapest batch was 45 cents a gallon, usually 50-55 cents.
problem now though is restaurants are either starting to charge for the veggy oil pickup, or somebody has already gotten that restaurant. need to put the processor in a well ventilated area, mine was outside with a roof over my head (no walls). processor itself wont make any fumes, but the methanol will.
complicated? its high school level chemistry. the lye mixes with part of the veggy oil to become bio, the rest of the veggy oil becomes glycerine. the methanol is a catalyst, not used up in the reaction. roughly 80% of each batch becomes biodiesel, so 20 gallons of veggy oil 16 gallons should become bio (give or take a little bit depending on how much water is in the mix).
those steps work with veggy oil, canola oil, etc etc. when i'm done with the air force in a couple years i'm thinking about messing with biodiesel from the engineered algae, the fuel grows much much faster. there is also thermodepolymerization, basicly breaks down trash into a few parts. water, a form of diesel fuel, and a salt are what comes out. tyson chicken has a contract in oregon with a company thats doing that with the chicken carcasses.
running straight veggy oil, cheapest form of fuel but requires modifications and DOES have a setback that bio doesnt. you can run a percentage of pure veggy oil in your motor without heating it, depends on the outside air temps and what motor you have (powerstroke is very picky for some reason, bad idea with that motor). to run pure veggy oil though you need a 2 fuel tank system in your vehicle. 1 tank with regular or biodiesel for the startup/shutdown time, about 10-15 minutes each. the other tank with heaters installed in it for the veggy oil. also requires heating the fuel line and the filter in colder climates. need to run the engine on regular or bio diesel for the last 10-15 minutes to clean the fuel lines out from the veggy oil, pumps arent very happy to try to run thick cold veggy oil through and will kill the pumps FAST.
downside to straight veggy though is the acidity of oil that has been heated many times. if your going to run straight veggy make sure you get your oil from somebody that changes the oil often. where the acidity comes into effect is with the lift pump, injection pump, and injectors, they will slowly be eaten apart internally. lift pump not a huge deal, about 100 bucks usually and not too difficult to replace. injectors a little bit more but same problem. injection pump though, expecially on a V style motor, big money and expensive to replace, looking at 1500-2800 for a shop to do it or 500-1200 for a pump and doing it yourself which is not fun. including the filters your looking at about 20 cents a gallon for veggy oil because there is no chemistry involved, processing is just filtering it a couple times to get the food particles out and water as well. conversion though can get pricy, cheapest setup i know of the guy has spent about 400 bucks so not bad, other setups can run over 5k.
