So you want to make your own biodiesel…


I knew I was hooked when I took my first sip of a liquid I realized could power a car, was clean enough to drink, and that I could make myself for less than a dollar a gallon. This was also back in ’03, when the Iraq war was starting, and I found myself getting excited about the idea of making my own fuel as one thing I could do to remove myself from supporting the petroleum economy. Making your own fuel is revolutionary in the same way as getting your food from local farms; in both cases you’re relying on local sources instead of mega-corporations. It’s even more fun when you get together with others and form a fuel-making coop with everyone gathering oil from local restaurants, as I did three years ago with the Dirty Hands Biodiesel Coop. Whatever your motivation, whether you are doing it by yourself or with others, making your own biodiesel fuel can be a rewarding activity. But there are some things to think about.

First of all, there are safety considerations. Even though the finished fuel may be clean enough to drink (don’t try this with commercial biodiesel as it’s mixed with petrodiesel), there are toxic chemicals that you must use in order to make biodiesel (that are later washed out of the finished fuel). The chemicals typically used are methanol (methyl alcohol) and lye (sodium or potassium hydroxide). Right away there are concerns about the storage and handling of these chemicals, and in some smaller towns, the fire departments have started shutting down homebrewing operations, or started to regulate them. The cheapest way to purchase methanol is by the 55 gallon drum, and although this alcohol is not nearly as flammable as gasoline, a drum of the stuff is definitely a fire hazard, and you will want to consider not only your own home but those of your neighbors. The best thing you can do is to simply seal up the drum after pumping the required amount of methanol for the batch of fuel you are making. It’s also best to set up in a separate building (a metal shed or container would be nice). You will also need to provide very good ventilation, because methanol is toxic to breathe (and ventilator masks don’t block it, so don’t rely on them). Similarly, lye is very caustic, and you will need to wear chemical resistant gloves and safety glasses when handling (a dust mask or respirator is also a good idea).

Once you’ve decided to go ahead, you will want to think about whether to build your own biodiesel processor or purchase one ready made. It kinda depends on whether you have more time than money, or vice versa. Do you love building things yourself, or would you rather just buy something that’s more or less plug-and-play? If you want to build it yourself, I believe the safest design is the so-called Appleseed, which is made using an electric water heater. Water heaters are very well insulated, and the Appleseed can be built without any welding. You can get the plans to build these for free at biodieseltutorial.com or you can purchase plans or the entire kit through utahbiodieselsupply.com. You will also need some kind of wash tank which can be a 55 gal drum or a plastic conical tank (use only low-heat aquarium type heaters if using a plastic wash tank). Most of the parts to build an Appleseed are various lengths of black iron pipe and brass ball valves that can be acquired at a hardware store.

If you have the money, and want to produce a fair amount of fuel quickly, then I’d recommend getting an automated processor such one of the BioPro’s (full disclosure: I am a dealer for them). Our coop has been using a BioPro for nearly three years and it has been a great machine, running 24/7 producing commercial quality fuel. You still have to measure out the chemicals and add them to the machine, but then it’s just a matter of pushing a couple of buttons (and draining the byproduct). The machine produces fuel in 48 hours, whereas it usually takes about a week to produce a batch of fuel using an Appleseed. Part of the time saving is due to the BioPro’s use of the acid/base method, which greatly reduces the amount of soap byproduct produced, and thus allows for faster washing.

So what exactly is the process of making biodiesel? Simply put, we perform a simple chemical reaction with methanol and lye to remove the heavy part of the oil molecule, and create a liquid that is less viscous, ie about the same viscosity as diesel fuel. (The original diesel engine was designed to be able to run on straight peanut oil, and even now you can run a diesel on straight veggie oil, but you have to install a kit that heats the oil up first in a separate tank in order to reduce it’s viscosity). In this reaction the methanol knocks the fatty acid chains off of the glycerin backbone (which falls to the bottom as waste), and part of the methanol gets incorporated into each fatty acid chain, forming what are known as Fatty Acid Methyl Esthers (“FAME”) or biodiesel. The tricky part is that the waste fryer oil that homebrewers use varies a lot in terms of the heat and length of time it’s spent in the fryer. The more used it is, the more broken down it is, so the oil needs to be tested to determine how much lye to use. This test, called a titration, is quite simple to do, and very important, so that you know how much lye to use in order to get good conversion of oil to biodiesel. Other things to do to get a good reaction include drying the oil (because water blocks the reaction and also creates soap), heating the oil to about 140 deg F, mixing properly, and using enough methanol (22%) and lye (determined based on titration).

After the reaction, the glycerin waste is removed from the bottom of the reaction vessel, and the fuel should be tested to see if a good reaction occurred. The 3/27 test is a simple test that gives a ball park answer as to whether the fuel is good, ie likely to pass the standard for commercial fuel. The fuel should then be washed with water (or dry wash system) to remove soap that is made as a side reaction, plus any residual methanol, lye, or other impurities. Once the fuel is thoroughly washed and dried, it should be filtered to 10 microns and is then ready to go!

As far as waste, the wash water is OK to go down the drain, since it contains biodegradeable common chemicals. The glycerin is more of a problem. The sewage treatment folks have told me that it should actually be good for the bacteria (as a carbon source), but they are not set up to accept anything from the public (ie containers of anything). The dump won’t take it, and neither will hazardous waste for some reason. You can recover quite a bit of methanol from it, and then compost the rest, or mix it with sawdust to create fire logs. You can also make an excellent soap from it (see plans at UtahBiodieselSupply.com), and there are a variety of other possible uses. A local biodiesel company has assured me that they will accept glycerin from homebrewers soon.

Making your own fuel can be a fun and satisfying experience, but be warned, it is a commitment of time and resources, and it can be addictive! Making biodiesel from used oil seems to me to be one of the most sustainable ways of producing fuel that exists, and results in far greater greenhouse gas emissions than even biodiesel made commercially. Plus, the only way to get true B100 is to make it yourself!

About Lyle::
Lyle Rudensey is the owner of BioLyle’s Biodiesel Workshop, LLC, which has provided biodiesel production workshops in the Seattle area, and is now offering a tutrorial DVD set, as well as automated biodiesel processors, biodiesel heating stoves, and other products. For more information, go to www.biolyle.com