Rapeseed is one of the most common crops grown for the production of biodiesel due to its high oil yields and environmental sustainability. Through the process of transesterification, rapeseed is converted into a high-grade methyl or ethyl ester fuel that is biologically renewable and less toxic than gasoline or regular diesel fuel. The process of turning rapeseed and canola, a type of rapeseed, into fuel is essentially the same as with any organic matter.
Cultivate the rapeseed, sowing the seeds in the winter or spring. Rapeseed is generally cultivated in industrial crop fields that generate large harvests for use as vegetable oil, edible protein and biodiesel. Rapeseed grows well in temperate zones in the European Union, Canada, India, China and across the United States.
Harvest your crops. Winter-sown rapeseed crops are ready for harvest in August, and those sowed in spring are usually ready by October but usually must be desiccated or swathed to allow for even ripening. Desiccation involves spraying chemicals on the crops to kill them, while swathing is a mechanical alternative. Ripe rapeseeds are small with a dull, brown appearance and a smell that resembles cabbage.
Use one of the many mechanical or chemical methods to extract the oil from the rapeseed. Extract the oil through a cold-press process; heat up the seeds to increase oil fluidity or use chemical solvent extraction methods.
Filter the oil to remove solid fragments. The byproduct of this process is healthy protein that can be used in animal and human foods.
Mix the methanol and potassium hydroxide in your biodiesel processor, allowing the catalyst to dissolve in the methanol. Add the rapeseed oil and mix the ingredients for about an hour, depending on the size and quality of your processor. Allow the mixture to sit overnight to complete the separation process.
Pour the biodiesel from the top of the processor and wash out the impurities by spraying the top of the container with water. Without causing any agitation, allow the water to sit with the biodiesel for 24 to 48 hours or until the water has settled.
Separate and dispose of the waste water. The final product is ready-to-use rapeseed biodiesel that can go directly into a biodiesel converted engine.
Try a small test batch before endeavouring in large commercial production.
Chemical solvents pose a risk to the environment and your health. Avoid hazardous vapours if you choose this extraction method.