C1bL6 Oil from Plants
Key Words
Biodegradable - material that can be broken down using micro-organisms.
Biodiesel - fuel made from methanol and plant oils.
Biofuels - fuels made from plant material.
Carbon monoxide - (CO), a colourless and odourless poisonous gas.
Distillation - Separation of a liquid from another liquid by boiling it off and condensing it.
Fuel - a material that is burned to give energy.
Green fuels - fuels from renewable sources.
Impurities - Materials in something that are no good for its purpose.
Methane - CH4, the simplest alkane.
Minerals - natural chemical compounds.
Molecules - the basic unit of a substance consisting of two or more atoms.
Natural Oils - oils from plants and animals.
Non-renewable fuels - fuels from crude oil.
Protein - huge molecules that are found in cells of living things.
Renewable fuels - fuels made from plants.
Resources - useful materials.
Solvent - substance that dissolves another substance.
Grade E
Many plants give us natural oils (as well as many other useful substances and materials). The oil is often found in the seeds or the fruit.
The seeds needed to be crushed in order to release the oil. The oil is not pure, so water and other impurities need to be removed.
Biodiesel is produced from plant oils. It is renewable. Fuels that come from renewable resources are often called green fuels.
Decomposing rubbish (including lavatory waste) gives off methane, which is used as biogas.
Grade C
The molecules in oils are very big, consisting of three long chains of carbon atoms attached to a central spine. They do not dissolve in water, and are less dense, so they float on top.
A solvent can be used to dissolve the oils, but it does not dissolve the water and other impurities. The solvent is then distilled off, leaving the pure oil.
Oils are very high in chemical energy. It is possible to run a diesel engine on plant oils; some people have their own apparatus for cleaning up waste food oils, and it costs them about 30 p (€0.40) per litre, compares with £1 per litre for diesel.
Plant oils can be a bit too viscous (gooey) to use in diesel engines, so they are often diluted with ordinary diesel. However the diesel engines may need to be adjusted, as burning fuels inefficiently may give out carbon monoxide, a odourless and colourless poisonous gas.
The nuts that produce natural oils often have very important nutrients that are good for our health. However the castor oil bean has a very poisonous substance, called ricin. Eating castor beans is NOT recommended.
Grade A
The oils in many nuts contain omega-3 fatty acids which are thought to:
- lower blood triglyceride (i.e. fats) levels;
- reduce the risk of blood clots;
- lower blood pressure;
- improve brain function
Fish oils are also thought to be rich in omega-3 fatty acids.
Biodiesel is biodegradable, and has little sulphur, so it's much cleaner than normal diesel. The plant oils are mixed with methanol to form methyl esters. The reaction also forms glycerol, which separates from the biodiesel as it's denser. The glycerol can be used for other purposes. The process is called transesterification.