Biodiesel can be made at home using waste vegetable oil, hence making it all the more environmental-friendly.
Precaution: Ensure that pump to transfer methanol is labelled for alcohol as methanol, being an alcohol, is corrosive and pumps made of materials like metal can be corroded. In addition, alcohol is highly flammable so wear thick synthetic rubber gloves when handling methanol. As it is also very volatile, do not breathe in too much of it. It is advisable to wear a respirator.
Amount needed: For the 15 litres of vegetable oil mentioned at the start, 2.6 litres of methanol is required.
Lye (Sodium Hydroxide)
Precaution: Sodium Hydroxide is a very strong alkaline. Hence, when in contact with skin, it can cause serious burns. Thus, wear rubber gloves at all times when handling it.
Amount needed: The mass of lye to add is of the essence in this whole process as it will affect the molar ratio of the reagents, hence determining the success or failure of the whole process of making biodiesel. For the 15 litres of vegetable oil mentioned at the start, 53 grams of lye would be appropriate. It is preferable to use a sensitive electronic balance to measure out the lye.
Prepare about 15 litres of vegetable oil.
Put the vegetable oil in a steel pot and heat it on a camp stove at roughly 100 °F. This allows us to carry out the whole process in the same area, i.e. the basement where the car is. Point to note here is not to overheat the oil as it will result in undesirable reactions between secondary ingredients. Alternatively, for days when the weather is hot, put buckets of vegetable oil under the sun instead of heating on a stove. After a few hours, they would be ready for processing. As the oil is warming up, carry out other steps.
Keep the protective gears on even after dispensing the ingredients as Step 2 is the mixing of these ingredients and the resulting chemical, sodium methoxide, is equally dangerous as the ingredients used to form it.
Any mixing tool and container is possible. Just grab anything you can see in your house that is not easily corroded. The bore of the mixing tool may be attached to a hand drill to speed up the mixing process. When hand drill is used, mixing would be completed in about 5 minutes.
N.B. mixture will get hot due to chemical reaction during mixing.
Prepare a spotlessly clean spackle bucket and pour the heated vegetable oil into the bucket.
Then, pour half of the sodium methoxide to the oil into the spackle bucket. Mix the other half again for about 1 to 2 minutes. This is to ensure all the lye crystals dissolve completely as any undissolved lye crystals can cause the reaction to fail. Now, add the other half to the spackle bucket. There will be little bubbles and swirls observed and the colour is translucent brown.
Use a low-cost drill operated paint mixer or any other equipment that can perform the same function to mix the sodium methoxide with the oil.
As the mixer rotates for the initial couple of minutes, you may hear the motor slow down as if there is a load on it. This is because the mixture is thickening to some extent before the glycerin group segregate from the vegetable oil – the mixer will spin faster then.
After the first couple of minutes, you would have confirmed if you are on the right track. Then, cover the bucket to prevent splashes and at the same time, ensure the cover has a hole for the mixer to pass through to mix the solution. Set speed of mixer to 1,000rpm and leave it mixing for half an hour to ensure complete reaction.
Next, put the bucket aside, seal it with a lid and leave it overnight for the glycerin to settle down (approximately 12 hours).
The final step now is to remove the glycerin that settled at the bottom.
The common solution is to use commercial grade restaurant filtering bags which have sieves in the 5-10 micron region. This makes it possible to remove all residues in the biodiesel. The less impurity there is in the biodiesel, the lighter the load on the car and the longer the filters in the car will last.
Now, is the moment of excitement! You can pour the biodiesel into the car whichever way you prefer but the most economical is to use a funnel. The proportion to add to diesel fuel depends on the climate of the country you are living in and it is up to you to experiment.