What is Biofuel
Biofuels are produced from vegetable matter and they account for 15% of the world’s energy production. These are mainly used in LEDC’s(Less economically developed countries) for cooking and heating. For example oilseed rape can be converted into biodiesel fuel.
Now scientists are interested in biofuels for transport.Italy produces some of it’s diesel form rape seed oil,and 5% of Australia’s diesel is biodiesel.
* Sugar cane and wheat can be fermented to produce ethanol which can be either used on its own or blended with petrol.Seeing that the world’s supplies of oil are going to run out by the end of the Twenty-first century another possibility is Hydrogen (derived from water) it has many advantages, when it burns it has no harmful products and it gives out more energy per gram than natural gas or petrol. Not only this but existing car engines need only minor changes to adapt to this source.
* So what’s stopping us splitting water now to get hydrogen??….well that’s because a lot more energy is needed as in the UK we would have to burn fossil fuels to get the energy to do this which cancels out any environmental advantages!
* Another problem is how to carry hydrogen around, since to stay liquid and occupy a convenient volume it needs to be stored below -253c.
* On the bright side more efficient solar cells might provide energy to split water to electrolysis.
* Also one promising area of research is the use of metal hydrides, which are solid compounds of a metal and hydrogen and the hydrogen could be produced from them as needed by heating.As mentioned before storing hydrogen means cooling it to -253c which cots four times more than making the equivalent amount petrol.
* One possible method is storing hydrogen as a solid.This doesn’t mean freezing it, it means combining it as a metal hydride. Magnesium hydride MgHis 7.7% hydrogen by mass.
* A litre of magnesium hydride contains almost as much hydrogen as a litre of liquefied hydrogen, though it’s a lot heavier.
* An interstitial hydride can soak up hydrogen like a sponge. The metal is ‘bathed’ in hydrogen and at the metal surface the hydrogen molecules splits into it’s atoms and the atoms occupy holes in the lattice. Very large quantities of hydrogen and be absorbed and released on heating. And in regards to the heavy weight of the hydrides chemist’s are looking at alloy hydrides which don’t weigh as much.
A fuel is a substance that releases energy that can do work. Most fuels release this energy during combustion reactions. And they release their energy when they make bonds with oxygen.
So what properties make an ideal fuel?
…Petrol is a popular fuel but is it ideal?
For it’s mass petrol produces a lot of energy, which makes the expense of transporting and storing it worthwhile. It doesn’t produce solid waste that needs to be dumped. But an ideal fuel produces no harmful by-product when it burns and petrol does (CO2) .Even if it’s just CO2 and water we know that CO2 is a harmful greenhouse gas and it’s continued output today will lead to global warming.