Well, after 1 1/2 years, we've made 540 gallons of biodiesel in our appleseed processor and driven somewhere north of 13,000 miles on this renewable, CO2 neutral fuel. With the current batch of homebrew B100, our total cost per gallon will be $3.09, now under the market price for dino-diesel! From here on out, the basic costs will be around $1.00/gallon for biodiesel and $0.25/gallon for filtering used vegetable oil. We currently the Jetta TDI has been running smooth as silk and by next month we'll have the '87 Westy Syncro TD Vanagon running biodiesel with a vegetable oil conversion getting an estimated 28-30mpg. Assuming that we drive a combined 15,000 mi/yr and take into consideration mileage, we'll spend $269 on biofuel as opposed to $1394 for fossil fuel, saving $1125, reducing our cost by 80%, negating the CO2 emissions, and no longer require foreign or domestic petroleum. Granted, it takes time to do all this, but now that I have the process fairly wired, it takes less than 3 hours for a batch of 30 gallons.
I officially consider our biodiesel experiment a success! At the very least, we've broken even, decreased our fossil fuel use, and learned a ton. Plus, from here on out we'll be saving money as well as being part of the solution not the problem.
The actual process is simple - once the processor and wash tank has been built, the only other raw materials needed is methanol and potassium hydroxide. The basic formula is for every 1 liter WVO add 200cc MeOH and 7g KOH. Additional KOH needs to be added to account for FFA (free fatty acids) in the oil which is calculated in the titration phase.
Oil Collection/Filtration: I have tried various methods of collecting the waste vegetable oil from restaurants including mouth siphoning (blah!), siphon hand pumps, a 12V oil pump from northern tools, and "the Guzzler" (a heavy-duty hand pump), all of which were suboptimal in one way or another. The easiest and least messy way for me is to actually use a handled bucket dipped in the 55 gal barrel of WVO then pour it through a window screen funnelled into a 15 gallon container. I have 2 black plastic 15-gallon barrels that work perfectly. I have recently started to take advantage of the color of the container, leaving it out in the sun for solar preheating of the oil. Using the bucket method, I can collect and filter the big chunks out of 30 gallons of WVO in about 15-20 minutes. With our new SVO system in the Vegfalia, we'll be using the RoadTote from Vegpower which uses the Fill-Rite 1604 12V pump which has gotten rave reviews from SVOers and biodieselers. The RoadTote will allow us to filter WVO directly down to 5 micron fuel-grade on the fly provided that the oil does not have much suspended water.
Using the processor: You need to pay careful attention to the various valves and check to be sure that they are opened/closed properly for what you're pumping where.
Close the valve at the bottom of the processor, place the input/ouput hose into your filtered, hopefully solar preheated WVO and turn on the pump. The self-priming pump will slowly build the oil to a head then start pulling it into the reactor.
Turn on the heater (I had to turn the thermostat all the way up), turning on the pump every 15-30 minutes to circulate the heated oil. This allows you to see the true temp in the thermometer and prevents the thermostat from turning the the heating element off. Once the oil is up to 130 deg F, it is time to add the methanol and KOH.
This is where the danger of making biodiesel at home comes in. Methanol is highly flammable and toxic if ingested as well as having somewhat toxic fumes. KOH is highly corrosive and will cause serious chemical burns. Girl Mark told us a few homebrew SNAFUs such as the guy who tried to mix the methanol and KOH with a hand drill attachment and the sparks from the drill motor ignited the methanol fumes, taking off the guy's eyebrows and giving him 1st and 2nd degree burns. Be careful! When you think that you have a brilliant idea like that, think it over first!
The carboys for this system are 5 gallons and with 30 gallon batches you need 20% by volume methanol, so 6 gallons. I split this into two 3-gallon batches, mixing 1/2 of the KOH in each. I use a digital kitchen scale that works well to measure the KOH which is 7 + (titration value) grams/liter of oil used. To mix I've been just closing the carboy lids tight and swirling, venting occasionally due to the gas/heat produced by the reaction. Once dissolved, attach the hose from the reactor, set it on the shelf and with the pump on, open the valve to the methoxide tube and slightly close the valve at the bottom of the tank. While you're mixing the other half, the pump will slowly draw the methoxide in and begin the transesterification reaction to make biodiesel.
You can see the oil turn milky when the methoxide is mixing in, a sign that you've done it correctly. Leave this mixing for 1-2 hours, leave overnight and viola! Drain the waste glycerin off the bottom and you have raw biodiesel on top!
Washing the fuel: I modified my setup slightly to allow me to divert the raw fuel into the washtank so I can simply close the valve going up and back into the processor and open the valve to the washtank and turn on the pump. I used a bulkhead fitting to attach the hose to the washtank.
I have both of the recommended wash methods working well - the misters and the bubbler. It seems that the bubbler can be too vigorous and cause emulsification (leaving you with a vat of mayonnaise looking stuff) so its recommended to mist first. I've been misting 3 times, emptying the washwater from the left or low pipe the first 2 times, then using the bubbler with the water from the 3rd wash. This seems to work well as the water from the first wash is cloudy and soapy, the water from the 2nd wash is clearer, and the water after bubbling is fairly clean. I use a 120V wand-type drum heater during the bubbling stage and for 24 hours after to help in drying.
is built an 8' by 4' shed behind my house for the processor with a 2X6 frame around the bottom coated with a polyethylene tarp to act as a secondary containment unit in case of spills. Power is a simple extension cord to a power strip and a homemade switchboard for the pump, heater, and bubbler/washer. Total cost = approx $1000. This can be done much more cheaply by scavenging many parts.
and the processor itself is based directly on Girl Mark's Appleseed processor with a few modifications. It is a Sears 220V electric hot water heater with a 110V element installed - although you can run a 220V heater on a 110V circuit, it is much less efficient than simply changing out the element. Although the chicago tools water pump worked well enough initially (especially for the price), I changed to a central machinery 1/2 hp self-priming pump, making it easier to draw the oil into the processor.
is an upside-down 55-gallon barrel sitting on a milk crate with a standpipe setup. There is a pipe threaded though each of the bung holes, one approximately 8" high and the other at the bottom of the tank. A 5 piece mister is attached to the "lid" for the first 2 phases of the washing process and an aquarium bubbler with Girl Mark's modified washer tube is submersed in the water layer for the third phase.
our first 5 gallon fillup!