Transesterification: turning used vegetable oil into clean burning biodiesel fuel 1
Biodiesel Recipe from New Oil 1
University of Idaho: Transesterification Process to Manufacture Ethyl Ester of Rape Oil by Roger A. Korus, etal. 1
Ingredients 1
Washing the Biodiesel 2
University of Idaho: Production & Testing of Ethyl and Methyl Esters by Charles L. Peterson, etal. 1994 2
Methyl Ester Biodiesel Ingredients 2
Methods 2
Anonymous Recipe 3
Ingredients 3
Products 3
Precautions 3
According to a report issued by the University of Idaho Department of Agriculture:
Transesterification is the process of using an alcohol (e.g. methanol or ethanol) in the presence of a catalyst, such as sodium hydroxide or potassium hydroxide, to chemically break the molecule of the raw renewable oil into methyl or ethyl esters of the renewable oil with glycerol as a by-product (1991).
Transesterification is not a new process. It was conducted as early as 1853, by scientists E. Duffy and J. Patrick (Production, 1995). One of the first uses of transesterified vegetable oil was powering heavy duty vehicles in South Africa before World War II. The name "biodiesel" has been given to transesterified vegetable oil to describe its use as a diesel fuel.
The methyl ester of vegetable oil, or biodiesel, is very similar to diesel fuel. Its viscosity is only twice that of diesel fuel and its molecular weight is roughly 1/3 of vegetable oil. Most diesel engines were designed to use highly lubricating, high sulfur content fuel. Recent environmental legislature has forced diesel fuel to contain only a minimum amount of sulphur for lubricating purposes. Thus, the slightly higher viscosity of biodiesel is helpful & lubricating to most diesel motors. Waste fryer oil, a commodity which is considered toxic waste by the EPA, can also be transesterified into biodiesel.
The process of converting vegetable oil into biodiesel fuel is called transesterification and is luckily less complex than it sounds. Chemically, transesterification means taking a triglyceride molecule, or a complex fatty acid, neutralizing the free fatty acids, removing the glycerin, and creating an alcohol ester. This is accomplished by mixing methanol (wood alcohol) with lye (sodium hydroxide) to make sodium methoxide. This dangerous liquid is then mixed into vegetable oil. The entire mixture then settles. Glycerin is left on the bottom and methyl esters, or biodiesel, is left on top. The glycerin can be used to make soap (or any one of 1,600 other products) and the methyl esters is washed and filtered. The resulting biodiesel fuel when used directly in a Diesel engine will burn up to 75% cleaner than petroleum D2 fuel.
Following are recipes from research reports acquired from the National Biodiesel Board.
University of Idaho: Transesterification Process to Manufacture Ethyl Ester of Rape Oil by Roger A. Korus, etal.
Dissolve the catalyst in the ethanol, which will require stirring and slight heating. Add the ethanol/catalyst mixture to the oil and stir the mixture vigorously. After 120 minutes of reaction time at room temperature, the mixture was allowed to sit overnight while separation occurs. Pour off the biodiesel from the top of the container.
Water is sprayed at low velocity on top of a tall column of biodiesel. The water will wash away any excess alcohol and catalyst. It will emulsify somewhat with the biodiesel. The less this is agitated the better, as agitation will cause more emulsification and less useful biodiesel. Let this sit for 24-48 hours until the water has settled.
University of Idaho: Production & Testing of Ethyl and Methyl Esters by Charles L. Peterson, etal. 1994
For Methyl Ester Biodiesel
MeOH = .225 x Oil
KOH = Oil/100
where:
For Ethyl Ester Biodiesel
EtOH = .2738 x Oil
KOH = Oil/85
where:
The catalyst is dissolved into the alcohol by vigorous stirring in a small reactor. The oil is transferred into the biodiesel reactor and then the catalyst/alcohol mixture is pumped into the oil. The final mixture is stirred vigorously for 2 hours. A successful reaction produces two liquid phases: ester and crude glycerol. Crude glycerol, the heavier liquid, will collect at the bottom after several hours of settling. Phase separation can be observed within 10 minutes and can be complete within 2 hours of settling. Complete settling can take as long as 20 hours.
After settling is complete, water is added at the rate of 5.5 percent by volume of the oil and then stirred for 5 minutes and the glycerol is allowed to settle again. Washing the ester is a two-step process which is carried out with extreme care.
Mix up your recipes in a well-ventilated (or outdoor) area with access to water & electricity. Have lots of detergent and newspapers on hand. A good respirator, safety glasses, plastic apron and decent rubber gloves are recommended. Never use utensils or measuring cups for food consumption again!
Methanol is toxic. Absorbed by the skin, it can cause nerve deterioration with prolonged usage. It can also cause blindness if splashed in eyes - so wear protective goggles. Could be fatal if swallowed. Dry gas methanol can be found at automotive racing stores.
Lye is also very toxic. It burns the skin upon touch & is extremely damaging if ingested.
Strain used vegetable oil through a coffee filter or cloth before mixing. Dispose of glycerin at your local toxic waste disposal site if you can't use it.
