Each fraction can have a number of different uses. For example most of them create mainly fuels but others can also be turned into plastics;
Very few of the substances above come out of the fractional distillation column ready for the market. Some fractions such as the residue from the distillation tower need to be transformed into new components. Low-value fractions that aren't in great demand can be converted to petrol and other useful chemicals. The most used conversion method is called cracking because it uses heat and pressure to crack large hydrocarbon molecules into smaller ones. Catalytic cracking is the basic process used in the process of making petrol. Using intense heat (600°C), low pressure and a powdered catalyst (a substance that speeds up a chemical reaction), the catalytic cracker can convert most heavy fractions into smaller more useful molecules. This process is also a way of preserving oil.
Fossil Fuels play a huge part in our world but bring as many problems as they do advantages.
Fossil fuels contain a large amount of energy with in them, with ability to generate huge amounts of electricity in just a single location, this means that power stations that make use of fossil fuel can be constructed almost anywhere; this is possible as long as large quantities of fuel can be easily brought to the power plants. These factors make using fossil fuels convenient. Fossil fuels are also cheap and relatively easy to find. Hence why they’ve been used for long enough that we’re used to depending on them.
However there are some major disadvantages of using fossil fuels the first one being pollution. When fossil fuels are burnt many harmful gasses can be produced, for example carbon monoxide. Carbon monoxide comes from incomplete combustion and can be seen in the form of smoke or soot; it can be very dangerous as it reduces the amount of oxygen that the haemoglobin part of the blood can carry around the body, this can eventually lead to death. Fossil fuels also produce carbon dioxide when burnt. Scientists suspect that this is one of the main causes for the greenhouse effects. Sulphur dioxide and nitrogen oxides can also be produces which combine high in the atmosphere and create acid rain. Acid Rain causes the weathering of limestone, encourages aluminium ions, damages trees and more. The mining and extraction of fossil fuels also damages the environment, for example the mining of coal results in the destruction of wide areas of land. Mining this fossil fuel is also difficult and can be incredibly dangerous to the lives of miners. This is not the only disadvantage however; fossil fuels (particularly crude oil) are expected to run out within the next century if the current demand for oil continues. We depend on fossil fuels to heat our homes, run our vehicles, power industry and manufacturing, and to provide us with electricity, so life without them would be exceedingly difficult, however we do have lots of alternatives which we could use to generate electricity etc, for example:
Solar power
Every year, the earth gets more than enough energy from the sun as much as 35,000 times the total energy needs of man. This form of energy can be used in furnaces for homes and for heating swimming pools. Its major applications are in power plants, space ships and in running cars. The energy from the sun is free and plentiful resource and does not produce greenhouse gasses, meaning that it would not affect the environment, however it would be very expensive to build solar power stations and it would not produce electricity on a cloudy day, or during the night, making the resource quite unreliable.
Wind Power
Wind power is the exchange of wind energy into a useful form of energy, such as using wind turbines to make electricity. The kinetic energy of the wind is used to drive the turbines and generators. Wind is a renewable resource and free, meaning that the only cost would be for the find turbines, it is also environmentally friendly and will not produce harmful gasses. The disadvantages of wind power are that the amount of electricity created from the turbines will depend on how strong the wind is, so when there are days with little wind, very little electricity can be produced. There will also need to be a lot of wind turbines to generate enough electricty, however most areas are built up and many people feel that turbines spoil the scenery and complain about the noises that they make.
Nuclear Power
Nuclear energy is in the nucleus of an atom. To generate electricity, nuclear energy should be released. It can be released from an atom in two ways; nuclear fusion where energy is released when atoms are combined together to form a larger atom or nuclear fission where atoms are split apart to form smaller atoms releasing energy this process is a very clean way of making electricity but its downfall id the danger of the high levels of radiation and also the chance that the reactor could explode. Nuclear fuel does not make harmful greenhouse and requires a very small amount of fuel to make a large amount of energy. However it does create waste substance which is radioactive and very harmful which must be disposed of very carefully.. Nuclear power stations are also prone to terrorist attacks and accidents which can affect the whole world. Uranium supplies may also run out.
Geothermal power
Geothermal energy comes from the earth’s core where temperatures are high and constant all year round. Water is pumped underground and gains heat energy from deep rocks underground. The heat energy is then converted into kinetic energy in the turbine, which turn the generator to produce electrical energy. Geothermal energy is ideally used in home heating systems because of its benefits. It can also be used to generate steam to operate a steam turbine. Geothermal power requires no fuel and so the costs are low, however there are not many places where geothermal power stations can be built, and harmful gases and minerals may occasionally come up from below the ground. These can be difficult to control.
Hydrogen
Hydrogen is often seen as an environmentally friendly alternative to fossil fuels and biofuels. When hydrogen burns, the only product formed is water. Most hydrogen is made by reacting steam with coal or natural gas, which are non-renewable resources. Hydrogen can also be made by passing electricity through water, although, most electricity is generated using coal and other fossil fuels: any pollution from burning these fuels just happens at the power station instead of at the vehicle itself. Another problem with hydrogen is that it is very difficult handle. Hydrogen gas is very flammable can explode it is handled in te wrong way, so therefore It is not as convenient as petrol and diesel. There are Some hydrogen-powered vehicles on the road today, however there are difficulties involved in making and handling hydrogen.
In conclusion all energy resources have their advantages and disadvantages. Fossil fuels and nuclear energy have the worst side effects and are non –renewable so alternatives must be found and used. The change from fossil fuels which have been used for 100’s of years, to something brand new will be difficult, and ‘spoil’ the scenery but will be a small proce to pay in order for our planet and race to survive.
References
Chemistry/Physics Exercise book
Edexcel IGCSE Chemistry Revision Guide (Page 89)
By Bryony Upson 10J