The process of making biodiesel at home can be fairly simple, though you should make sure to have all the necessary components and safety equipment before you attempt it. The three basic ingredients required to make biodiesel are triglycerides, alcohol, and a catalyst. Your source of triglycerides can be any type of animal or vegetable oil, and the easiest process typically involves using methanol and lye for the alcohol and catalyst. When you combine these three ingredients in the correct amounts, the lye can knock glycerin molecules from the triglycerides and allow them to recombine with molecules from the methanol. This procedure allows you to create biodiesel at home, though you may want to process it further so that it will work better.
When you make biodiesel at home, you will typically need to use a container made out of a material which won't break if dropped or react with chemicals, such as high density polyethylene (HDPE). Your triglycerides can come from vegetable oils or animal fats, but if they have been previously used for cooking you will need to go through some sort of straining and purifying procedure. The lye catalyst can come from a variety of sources, though potassium hydroxide, or potash, is typically easier to find.
Before making biodiesel at home, it can be a good idea to dress in protective clothing and wear gloves. Some solutions of lye can cause burns if they get on your skin, so it is always a good idea to take the necessary precautions. When choosing protective gear, make sure to wear clothing and gloves that will not react adversely to the chemicals you are going to use in the transesterification process.
The first step in the process is to measure out an amount of methyl alcohol and place it into the container. After that you can mix in the correct amount of lye, put a lid on the container, and agitate the ingredients into a solution. The next step is to heat up the vegetable oil or animal fats that you want to convert into biodiesel. After the oil is warmed up, it can be placed into a mixer along with the solution of alcohol and lye.
In order to ensure that the transesterification process is successful, you will typically want to mix the triglycerides, alcohol, and lye together for half an hour or more. You can then pour the mixture into clear containers. Over time, the glycerin will settle out of the mixture and the biodiesel will rise to the top. At that point you can siphon out the top layer for use in a diesel engine.
The product you end up with after making biodiesel at home may contain undesirable substances, such as methanol and water. Additional processes can be used to extract these substances. These additional procedures are not absolutely necessary, but they can result in a cleaner burning and more efficient fuel.