Biodiesel science fair project details:
The world is fast consuming petroleum reserves and soon going to face the fossil fuel shortages. Many nations are facing the economic crisis due to high import costs of petroleum products. This is necessitating the world to look for alternative fuels and better renewable sources. It is up to the humans to take up the challenge and develop viable technologies to make alternative fuels replacing petroleum. Here is good chance for students to take part in this challenge and show their ability experimentally at science fair.
Biodiesel is a renewable fuel that can be manufactured from vegetable oils, animal fats, or recycled restaurant grease for use in diesel vehicles. Biodiesel is usually made from plant oils or animal fat by reacting oil with alcohol in the presence of a catalyst. It is both non-toxic and renewable. Since biodiesel essentially comes from plants and animals, the sources can be replenished through farming and recycling.
Biodiesel's physical properties are similar to those of petroleum diesel, but it is a cleaner-burning alternative since it has almost no sulphur content, no aromatics and has about 10% built-in oxygen, which helps it to burn fully. Using biodiesel in place of petroleum diesel, especially in older vehicles, can reduce emissions. Its higher cetane number improves the ignition quality even when blended in the petroleum diesel. Biodiesel is safe and can be used in diesel engines with little or no modification needed.
Although biodiesel can be used in its pure form, it is usually blended with standard diesel fuel. Its higher cetane number improves the ignition quality even when blended in the petroleum diesel. Blends are indicated by the abbreviation Bxx, where xx is the percentage of biodiesel in the mixture. For example, the most common blend is B20, or 20 percent biodiesel to 80 percent standard. So, B100 refers to pure biodiesel.
PROJECT: This science project is based on Used Vegetable Oil. Used Vegetable Oil is reacted with alcohol and sodium hydroxide in the presence of a catalyst, filtered to obtain biodiesel. Student team can make a table top production plant for biodiesel and a batch could be prepared experimentally.
Basis: A city with one million populations would be generating about eight tons of used vegetable oil at various restaurants that could be converted to biodiesel. The Biodiesel thus produced could meet a 3MW generation unit fuel requirements.
Plant or equipment requirements:
Reaction Kettle (5 liter capacity)
Slow Stirrer
Thermometer
Heater
Filter Column
Measuring Vessels
Safety gloves & goggles
RAW MATERIALS:
Used Vegetable Oil; Methyl Alcohol; Sodium Hydroxide
PROCESS:
· Acid Esterification. Oil feed stocks containing more than 4% free fatty acids go through an acid esterification process to increase the yield of biodiesel. These feed stocks are filtered and preprocessed to remove water and contaminants, and then fed to the acid esterification process. The catalyst, sulfuric acid, is dissolved in methanol and then mixed with the pretreated oil. The mixture is heated and stirred, and the free fatty acids are converted to biodiesel. Once the reaction is complete, it is dewatered and then fed to the transesterification process.
· Transesterification. Oil feed stocks containing less than 4% free fatty acids are filtered and preprocessed to remove water and contaminants and then fed directly to the transesterification process along with any products of the acid esterification process. The catalyst, potassium hydroxide, is dissolved in methanol and then mixed with and the pretreated oil. If an acid esterification process is used, then extra base catalyst must be added to neutralize the acid added in that step. Once the reaction is complete, the major co-products, biodiesel and glycerin, are separated into two layers.
· Methanol recovery. The methanol is typically removed after the biodiesel and glycerin have been separated, to prevent the reaction from reversing itself. The methanol is cleaned and recycled back to the beginning of the process.
· Biodiesel refining. Once separated from the glycerin, the biodiesel goes through a clean-up or purification process to remove excess alcohol, residual catalyst and soaps. This consists of one or more washings with clean water. It is then dried and sent to storage. Sometimes the biodiesel goes through an additional distillation step to produce a colorless, odorless, zero-sulfur biodiesel.
· Glycerin refining. The glycerin by-product contains unreacted catalyst and soaps that are neutralized with an acid. Water and alcohol are removed to produce 50%-80% crude glycerin. The remaining contaminants include unreacted fats and oils. In large biodiesel plants, the glycerin can be further purified, to 99% or higher purity, for sale to the pharmaceutical and cosmetic industries.
Ø Dilute acid esterification to be carried out if found required based on the fatty acid content in used vegetable oil (rarely required).
Ø 250ml methanol is taken into a jar and 2gms of Sodium hydroxide is added to make sodium methoxide.
Ø The oil is preheated up to 50 degree Celsius.
Ø Sodium methoxide solution is gradually poured into the oil and is stirred continuously for 15 mins.
Ø The mixture is let to settle down until the glycerine produced during the reaction settles down.
Ø The bio-diesel is decanted into the filter column which filters all the impurities such as water and other unreacted agents.
Basic preparation of biodiesel remains the same but for different filtration techniques. There are two types of bio diesel filtration namely wet wash method and dry wash method. In wet wash method the impure biodiesel is washed with water repeatedly and filtered to remove glycerine traces, unreacted acids, etc. In dry wash method the impure biodiesel directly fed to the filtration column consisting of different filter bed materials that would absorb unreacted oils, glycerine, water, etc. Dry wash method is advantageous because it consumes less water and less time resulting in reduced effluent problems and increased productivity.
Following precautions need to be taken by the students:
· To wear gloves and goggles while conducting experiment.
· To be cautious when using electric appliances for heating and stirring.
NOTE: This project is prepared in a simple manner keeping in view of students. More technical, statutory and commercial details could be obtained from library and internet.
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