Quick Answer
To remove contaminants from used cooking oil for biodiesel, you'll need to filter and degum it, and then neutralize the free fatty acids. This process requires a combination of physical and chemical methods. Start by filtering the oil through a series of filters to remove solids and water.
Filtering and Degumming
Filtering and degumming are essential steps in preparing used cooking oil for biodiesel production. To degum the oil, add 1-2% of a degumming agent, such as phosphoric acid, and mix well. The acid will react with the phytates and other impurities, forming a precipitate that can be removed by centrifugation or filtration. The oil should be filtered through a series of filters, including a coarse filter to remove large particles and a finer filter to remove smaller particles and water.
Neutralizing Free Fatty Acids
Neutralizing free fatty acids (FFAs) is a critical step in preparing used cooking oil for biodiesel production. FFAs can be neutralized by adding a base, such as sodium hydroxide (NaOH) or potassium hydroxide (KOH), to the oil. The amount of base added should be 1-2% of the oil weight. The mixture should be stirred well and left to react for 30 minutes to an hour. After the reaction is complete, the oil should be filtered again to remove any remaining impurities.
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