Wondering Why People Make Homemade Biodiesel?

What's Involved in the Process

This article is written for those who are interested in learning about the production of homemade biodiesel fuel, but they know they won’t be doing it themselves. If you’re nosey, like I am, you probably just want to know the steps involved in the process without getting too technical.

There are 8 general steps in the production of biodiesel fuel:

   1. Filtering waste vegetable oil
   2. Water removal from oil
   3. Titration
   4. Preparation of sodium methoxide
   5. Mixing
   6. Settling
   7. Washing
   8. Quality check

Step one assumes that you are using waste vegetable oil. Of course you can use fresh oil, but it just makes sense to reuse something that is just going to be thrown out anyway. As you can imagine, used oil must be filtered to remove the dirt and food particles. Many people buy used oil from restaurants like McDonald's. I still find it amazing that used oil can be used to produced fuel. Guess it just satisfies the "waste not, want not" part of my personality.

The next step that needs to happen is to remove excess water from the oil. This can be done by heating the oil and boiling out the water. Getting rid of excess water is important because it can slow down reaction time and cause soap to form...not good for biodiesel.

You are proably asking yourself, "What in the world is titration?" Well, I'm going to tell you. In layman's terms titration is adjusting a dosage until you get the effect you are looking for. For producing biodiesel you will need to know how much lye will be needed. This is quite an involved step and very important to the success of your batch of biodiesel so I will briefly explain what is involved without getting to techy. You have to dissolve some lye in distilled water and this becomes your reference tester. It can be used many times so make sure to keep it clean. Next you mix isopropyl alcohol with some of your waste vegetable oil. Then you need an acid-base indicator to add to your solution. Again, I'm not giving specific measurements because this is just for educational purposes and not meant to be a recipe. Then you take your lye and water solution and add it to your waste vegetable oil solution, one drop at a time with the goal being a pink color that lasts for a few seconds. At this point, based on how many drops of the reference tester you used, you can figure out how much lye you will need for entire batch.

The fourth step is mising your methanol with your lye. This makes sodium methoxide. This is one step you have to be very careful with because sodium methoxide can burn your skin and ruin anything that is made of aluminum, tin or zinc.

The mixing step is when the waste vegetable oil is stirred while the sodium methoxide is added to it. It is during this step that the acutal separation occurs. The separation when the glycerine goes to the bottom and what is left on the top is your biodiesel.

During settling, the glycerine will form a mass on the bottom of the container. This usually takes about 8 hours. The glycerine is brown and believe it or not can eventually be composted. I think that is awesome! But be careful, you cannot compost the glycerine unless it has been treated to evaporate any residual methanol. If the original waste vegetable oil did not have excess water evaporated off it back in step one, then during the settling stage, you will see soap residue form in the biodiesel.

It seems like everything needs to be washed these days and biodiesel is no different. The purpose of washing the biodiesel fuel is to get the soaps out of it. There are a few different methods of washing the biodiesel and the easiest seems to be to let the fuel sit for a week so the soap will settle and then you can filter it.

We all know what a quality check is. To check the quality of your batch of biodiesel, you will need to check the pH with pH paper or a digital tester if that is available. The fuel should be clear with a light brown tint to it.

So that's it in a non-techy way. I hope you have learned something abou the process that is involved in producing homemade biodiesel fuel.