Today, rape plant is used mainly for the production of oil for the production of rape plant methylester for combustion engines, food oil or feed oil, production of pellets and to a lesser extent for the production of cosmetics. Crude rapeseed oil is produced by cold pressing or warm pressing of rape plant seed. It is an oily liquid, light brown or even gold coloured.
Rapeseed oil methylester is made of crude rapeseed oil by esterification. Rapeseed oil methylester is a clear, yellow liquid without any mechanical dirt and water; it may be mixed without any restrictions with diesel oil. It is not toxic, it does not contain any heavy metals or any harmful substances that may be bad for health; it is aggressive with common paints and rubber. For the production of rapeseed oil methylester, rapeseed oil is used as the initial material and a small amount of methanol and potassium hydroxide. The production of rapeseed oil methylester is a chemical reaction of oil, methanol and a catalyst for methylester and glycerine.
Rapeseed oil methylester is used in car industry as an important biofuel for combustion engines of lorries and passenger cars and agricultural machines where it substitutes for traditional fossil diesel fuel. In comparison with diesel fuel, during the combustion of rapeseed oil methylester the emission of unburnt hydrocarbons, particles and polycyclic aromatic hydrocarbons connected with them is significantly reduced. During the combustion of rapeseed oil methylester, CO2 produced during the fuel combustion is returned back to the natural cycle as a result of assimilation of newly planted plants. Contrary to the diesel fuel, plant oils do not contain any sulphur and so the combustion does not create any sulphur oxide SOx that creates acids in contact with air humidity and they are the cause of the so called acid rain. The high percentage of oxygen in rapeseed oil methylester has positive influence on oxidation and so on reducing smog rate in cities.
The EU legislative defines the ratio of biodiesel mixed in standard diesel and in this way diesel oil that is commonly sold in petrol stations is created.