Biodiesel

My First Batch of Biodiesel. The top, lighter layer of
liquid is the biodiesel, the darker layer at the bottom
is the glycerol separated from the cooking oil

A few years ago, I worked with a guy who ran his '80's something Mercedes diesel on used cooking oil he got from a friend of his who ran a diner. He would filter the cooking oil as he poured it into his garage holding tank, and then pumped it straight into the fuel tank when he needed a top-off. I always thought that was a great idea!

It's entirely possible to run a diesel engine like this, but it can cause some problems with the engine over time (which is why my friend used an old car). He said that he would frequently have to change his fuel filter and that his car smelled like french fries going down the road.

There are relatively simple processes that will allow a person to convert used cooking oil (animal or vegetable) into biodiesel that can be used by any diesel engine without the challenges that burning straight, used cooking oil presents. Today I spend an hour or so learning to make my own small batch of biodiesel.

There are many places to find info on the subject of biodiesel brewing, but for this table-top version, I turned to the National Sustainable Agriculture Information Service and their biodiesel page. They have a PDF entitled Biodiesel: Do-it-yourself production basics that has the recipe for this small batch. I was surprised at how easy it was to make it - just three ingredients and about 45 minutes and it was done.

For this particular batch, there are a couple more steps before it is useable biodiesel. I still have to separate the glycerol and wash the biodiesel to remove the soaps, residual glycerol, methanol and lye. Then it should be good to add to Bob the Tractor's fuel tank. The idea of being able to make my own fuel from waste oil is exciting! In the summer we use about 6-10 gallons of diesel every month. That's a $30-$40 savings every month if I could make enough. Plus, it removes waste oil that may be sent to the landfill and is cleaner and more efficient than petroleum diesel.

If you decide that you want to make your own diesel, be careful! The process uses some pretty nasty chemicals; methanol and lye specifically, that are bad for you. Make sure you wear rubber gloves and eye protection. Also, make sure that you don't release the chemicals where they can contaminate the environment.