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Making Biodiesel from Waste Cooking Oil
It is possible to make biodiesel from waste cooking oil. The process involves ensuring that there is a sufficient supply of waste oil. One needs to have sufficient containers and drums, as they will be required for putting the strained oil and the finished fuel. In addition, it is important to have the right safety equipment such as gloves, face protection, and aprons. This is because different chemicals are used in the breakdown of the waste oil to biodiesel. The face protection used should protect one from the poisonous fumes and it should include covering for the eyes. Most of the used cooking oil is collected from homes and eateries such as restaurants and diners. Some states have established collection zones for the used oil and they distribute it to people who are interested in making biodiesel. It is good to have adequate supplies of oil since the amount used in the beginning decreases throughout the process.
The first process when making biodiesel from the used oil is to sort it out. The oil often contains food particles and water since it has already been used. The particles are contaminants and they would make the process harder. Therefore, the next process is to screen the oil through the removal of large particles. One can use a mesh strainer to filter the waste oil. The oil is then placed in a tank where it is given time to settle. The tank helps in removing emulsions of water and oil. Used oil contains free fatty acids, which are formed when the oil is heated and cooked. The oil tends to be very acidic especially if it has been used for long. Therefore, a lot of lye is required to neutralize the acid.
Alcohol is used to break up the fatty acids in the vegetable oil. Methanol is commonly used for this purpose. The fatty acids in the vegetable oils are held together by glycerol molecules. It is possible to break the glycerol by using corrosive alkaline lye such as sodium or potassium hydroxide. Both are effective to use. One should ensure that he or she uses protection when handling potassium or sodium hydroxide because both chemicals are caustic. One should also avoid putting the chemicals on containers made from tin, zinc, or aluminum because they can react with each other. In addition, the chemicals should not be exposed to the atmosphere for a long time to ensure that they do not absorb water, as this can interfere with their effectiveness.
The use of lye turns the fatty acids soapy and it removes the glycerin from the oil. The next process involves mixing the lye with the methanol. One should make sure that the lye is completely dissolved in the methanol. The resulting mixture is called methoxide. It is then added to the warmed oil. One should stir the methoxide with the used oil and mix for an hour. The mixture is then given time to settle. This can last anywhere from twelve to twenty-four hours before decanting the biodiesel.
Performing a
quality test will determine whether the oil is safe to use. This includes performing
a wash test. Once the biodiesel decants the glycerin that is formed is removed.
The unwashed biodiesel is placed in a glass jar and equal amount of water is
added. The mixture is then shaken hard and allowed to settle. The two liquids
should separate after about half an hour. The water should settle at the bottom
and the interface layer between the two should be thin. If the mixture does not
settle, takes a long time to settle, or has a heavy interface layer, the
resulting product is poor quality and will not work well.
Work Cited:
Paul, Greg. Biodiesel: Growing a New Energy Economy. White River Junction: Chelsea Green Publishing, 2008. Print