How Is Biodiesel Made

Biodiesel is an alternative fuel that can be used in any diesel powered vehicle with little or no modification. It is cleaner burning and is a more environmental friendly fuel alternative. Biodiesel can also be used as a low carbon heating fuel. Over the last few years it has started to gain popularity. Have you ever wondered how this type of fuel is made? This article will give a simple explanation of how biodiesel is made.

How Is biodiesel made?
Biodiesel is typically made using either vegetable oil or animal fat oils mixed with an alcohol. It is made through a chemical process called base catalyzed transesterification. This simply means that the glycerin is separated from the fat or vegetable oil. To achieve this, the oil undergoes a number of steps.

The alcohol, which is commonly methanol, and the vegetable oil or animal fat are mixed together in a large mixing tank. The alcohol mixture also contains a catalyst such as sodium or potassium hydroxide.

The alcohol mix and the oil in placed in a reactor, which is a closed reaction vessel, and heated to 65 °C (150 °F) and pressurized to 20 psi.

The mixture is then transferred to a settler where the biodiesel and glycerin from the oil or fat separate. As the glycerin is denser than the biodiesel it is simple to siphon it off from the bottom of the tank.

For here the two distinct products biodiesel and glycerin that result from base catalyzed transesterification undergo different processes. The biodiesel is washed, purified and then any excess water is evaporated off the liquid. This results in pure biodiesel or methyl esters. It is then transported to storage area to await transportation.

The glycerin has a mineral acid added to it and it is placed in a distiller where neutralization occurs.
It is then placed in a settler and fatty acids are added. Finally it undergoes evaporation and becomes pure glycerin.

Related Article
Advantages of Biofuels