How to make biodiesel fuel

The biodiesel is one of the most versatile alternative fuels available, either because it is easy to manufacture or because of its low environmental impact. This natural diesel can be made from vegetable oil and even from used oil, making it an environmentally friendly fuel, as it allows us to recycle elements instead of discarding them. In this article we will look at how to make biodiesel in an artisanal way.

vegetable oil-based biodiesel fuel


To make the biodieselwe will use the following materials:

- Vegetable oil (the same oil we use in the kitchen).

- Methanol.

- Caustic soda (NaOH).

Biodiesel creation process

We will follow a simple procedure, but remember to treat chemicals with care and caution, keeping them away from fire and using surgical gloves when handling them.

To begin, we take 1 litre of vegetable oil (1000 ml) and place it in a mixing bowl or a glass container that must be completely dry. Put it on the heat and heat it to approximately 48 ºC, using a room thermometer or a cooking thermometer to measure it.

Simultaneously, in a separate cup that is well dried, pour 200 ml of methanol. Next, gradually add about 3.5 g of caustic soda (about ¼ teaspoon), then, using a wooden spoon, stir until all the caustic soda is dissolved. At this point, you should see a somewhat cloudy solution (sodium methoxide).

Glass canisters with biodiesel and glycerine

Once this is done, slowly add the methoxide to the hot oil, stirring constantly with the wooden spoon. If possible, we can use an electric whisk or a stirrer. The mixing process should take about 40 minutes. We can notice that the thick mixture becomes thinner and thinner, until it reaches a density similar to or even lower than that of vegetable oil.

Pour the mixture into a dry, tall, fine vessel (or a decanting filter) and let it stand for several hours until it settles. We can see that glycerine and soap may be found in the lower part of the vessel, due to sedimentation of the mixture, and that the biodiesel floats to the top of the vessel.

Description of the process

Biodiesel is the product of a chemical reaction called transesterification, which consists of replacing the methanol in the triglycerides of the oil in order to create a methyl ester (biodiesel). It is a fairly simple process, very similar to saponification (soap making process). With a little creativity, experience and changing vegetable oils, it is possible to obtain a higher quality biodiesel.

Biodiesel transesterification formula

3 thoughts on “Cómo hacer combustible biodiesel”

  1. I'm trying to make biodiesel with used oil but it's a bit thick and I don't know why, if someone can give me some advice, thank you.

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