Introduction. Crude oil is a resource that is essential in our society. Our lives virtually run on this fossil fuel, and it is hard to imagine a world without it. Though because fossil fuels are non-renewable sources of energy soon, this shall be the case. This paper will talk about crude oil as a valuable resource that will soon run out.
Formation: Fossil fuels are hydrocarbon-containing natural resources found underground. These natural resources were formed by the remains of animals and plants, also known as biomass, from over 150 million years; this is when the dead sea life and animals were buried under the sea bed. Over millions of years, the biomass became covered in silt, sand, mud, and various products that slowly formed into sedimentary rock.
Prices start at $12
Prices start at $11
Prices start at $14
Prices start at $12
The mass of sedimentary rock enables enormous pressure to be exerted onto the biomass, this factor combined with the temperature and the fact that there is little to no oxygen and there are bacteria that aids to decay the remains of the animals and plants, causes the material to become an oil or other fossil fuels. There are three prominent examples of fossil fuels, coal, natural gas and crude oil. All though they are all made similarly, they all vary slightly. For example, coal is formed by most mortal land-based plant life such as trees; the dead plant life then goes through the same high pressure and temperature as crude oil and natural gases.
The cellulose in from the dead plant-life changes into Humic acids, which is a product of incomplete decomposition of plant life. It then turns into bitumens, a vicious black liquid mixture of organic materials primarily composed of polycyclic aromatic hydrocarbons; it then becomes elemental carbon. Crude oil is the product of the decomposition of sea life, which is too buried under a sedimentary rock, put under the correct pressure and temperature from Crude Oil. This oil is deposited in porous rocks, seeping through the rock until non-porous rock stops it. With oil comes another fossil fuel that is natural gases.
Natural gases primarily consist of methane, which is found with other fossil fuels like coal or oil. It is formed by the anaerobic decomposition of methanogenic organisms and available biomass. Once these organisms are compressed, and if it is at a lower temperature, it becomes oil. The higher the temperature gets (going towards the earth’s core), the more gas gets produced, so natural gases are usually associated with Crude Oil—Diagram of the formation of crude oil and natural gas. Crude oil reservoirs are generally found in areas where there is a saline lake of the ocean.
Fossil fuels are often referred to as stores of the sun’s energy. This is true in some respects. Energy as we know it can never be destroyed, just transferred into different types. The plants and animals did get their energy from the sun. The sun also contributed to the heating of the surface, transforming the organic material into the oil. The oil we use results from the energy given to the animals that have died from the sun. The sun also helped in the disintegration of the animal after it is dead, but what people mean when they say that fossil fuels are stores of the sun’s energy is reinforcing the point of saying that the plants and animals that make the oil got their energy from the sun.
Heat and power will be produced as the chemical potential energy stored in the fossil fuel when Crude Oil or any fossil fuels are burned. This comes from the initially sunning energy stored in the living species (that under pressure and temperature became the fossil fuels) gets transferred into heat energy, light energy and power—valuable products from crude oil. Crude oil is the raw material that is then refined to get several beneficial substances. We find this resource so valuable to the compounds that it contains.
- (Cyclo= circular bond)
- These are unsaturated
- Hydrocarbons of which
There are many in crude oil. C6H5 – Y (Y is a longer, straight molecule that connects to the benzene ring) (The GENERAL formula)
- Other compounds
- 7% sulphur
- 0.1 Nitrogen
- 0.05% Vanadium
- 84% carbon
- 14% hydrogen
To understand how other products are taken from crude oil, one must examine the composition of the oil. Crude oil is a mixture of hydrocarbons (molecules that contain hydrogen and carbon in various structures). The compounds in crude oil are separated by fractional distillation. It uses the physical property of boiling points of the hydrocarbons to separate them. Smaller hydrocarbons have lower boiling points than significant hydrocarbons, and so they move further up the column, where constant vaporization and condensation occur as hydrocarbons rise.
The constant condensation and vaporization purify the liquid. A temperature gradient is used, and the different heights in the column correspond to the different temperatures. The fractions are used for different purposes. This depends on the temperature they are collected. The fractions are so important because they contain different hydrocarbons of different molecular masses. As a result, many valuable products come out of distillation, such as:
- Number of carbon atoms
- BP/ ï¿½C
- Refinery gas
- C1 to C4
- Below 30
- Bottled gas (butane or propane)
- C5 to C6
- Fuel for car engines
- C6 to C10
- Solvents and used in petrol
- C10 to C15
- Fuel for aircraft and stoves
- C15 to C20
- Fuel for vehicles and trains
- Lubricating Oil
- C30 to C50
- Lubricant for machines and engines
- C50 upwards
- Above 500
Road surface and roofing. Fractional distillation is started by putting crude in a fractional column, and a furnace is placed at the bottom, and it heats the crude oil. Compounds with lower boiling points evaporate and rise to the top of the column and are collected there. In this image, we see different parts of a refinery that are used to further convert fractions to gasoline, ethane and hydrogen. The fractional column is present with a reformer, alkylation unit, cracking units and a Coker.
Once the crude oil has been fractionally distilled, the fractions (stated above in the table) can be converted into more useful chemicals by the processes known as cracking, using the reformer, the alkylation unit and a Coker. Cracking is used to break down large hydrocarbon molecules into smaller ones so that they change their state and become more useful. Cracking is generally used to break down oils into the motor oil, jet fuel or diesel fuel as illustrated by the diagram.
There are two main forms of cracking, thermal decomposition: where the long chains of hydrocarbons are heated till vaporized. Or there is catalytic cracking, where a catalyst is used to break the hydrocarbon as well. Pollution emitting factories, use catalysts to break down the sulphur dioxide into sulphur and oxygen an example of cracking. In gasoline (a result of cracking crude oil) they must be having machines to take out impurities. In these machines, compounds are changed into other compounds. E.G
- C2H4+H2 C2H6
- C5H10+(catalyst) C4H10+C
- C5H10+(catalyst) C3H6+C2H4
These equations show the breakdown of hydrocarbons into smaller safer hydrocarbons. It can be seen in the second equation how Pentene gets broken down (with the help of a catalyst) into butane and carbon. Gasoline is a product of crude oil that is used every day by cars. In order to make it better, experts investigated how to make the gasoline smoother so that the car would run better. They realized that the answer was in the Octane number.
Gasoline needs a certain amount of octane molecules and a certain amount of heptane molecules. They realized that under compression heptane spontaneously ignited and octane didn’t, so in altering the composition of gasoline and setting the ratio of octane to heptane as 8 to 1 they were able to increase the quality and quantity of petrol.
Future developments: As was mentioned before, our world runs on fossil fuels, and it is this dependency that is causing many problems, such as polluting our atmosphere and due to it being a non-renewable energy source, it is quite costly and causes economic problems. Pollutants such as Nitrogen Oxides, Carbon Monoxide, Sulphur Dioxide and lead compounds, lead to a hole in our ozone layer as well as affecting millions, by polluting the air we breathe and giving people lung cancer and other problems.
- How Is It Formed?
- The Harm it does
- Carbon Monoxide
- A colourless gas, insoluble, no smell. Known as CO.
CO is formed when carbon compounds burn in too little air. For example inside car engines and furnaces. It is also formed when there is incomplete combustion. CO is poisonous even in low concentrations. It reacts with the hemoglobin in the blood and prevents it from carrying oxygen around the body causing oxygen to starving leading to death.
- Sulphur Dioxide
- Colourless acidic gas, sharp smell, soluble known as SO2
- Sulphur occurs naturally in fossil fuels. (Mainly in Coal and Oil) and forms Sulphur dioxide when these are burned
- Irritates the eyes and throat and causes respiratory problems.
- Dissolves in rainwater as it is soluble and forms acid rain, which erodes buildings, trees, and plants and kills fish and other river life.
- Nitrogen Oxides
- NO, and NO2 acidic gases
- Formed when Nitrogen in the air and oxygen react together inside hot car engines and in hot furnaces
- Causes respiratory problems and dissolves in rain to form acid rain.
- Tetra-ethyl lead: colourless viscous liquid, insoluble
- A compound called Tetra-ethyl lead was added to petrol to help it burn smoothly in engines.
- Lead damages Children’s Brain and adults’ kidneys and nervous systems.
- It poisons the catalysts in catalytic converters and stops them from working properly.
This concept was laughable a few years ago, but now people are standing up and acknowledging that this is a big problem. This is another problem with the combustion of fossil fuels. Yet demand keeps on increasing, and the refineries are finding it hard to keep up with demand. The slower and less available oil becomes, the higher the prices are, a problem we face now. Fossil fuels are known to be non-renewable because they took millions of years to form, and at the rate that they are getting used up, there will not be left to sustain us till more is formed; this being said, other alternatives have been looked into.
Alternatives such as biodiesels, natural gas, vegetable oils, hydrogen fuel cells, bio alcohols and nuclear power have been discussed. The problem with using natural gas is that it too is finite, just as fossil fuels are, though the concept of compressing natural gas (CNG) is a clean, energy-efficient fuel. Compressed air can also be used and is compressed at around 1/10 of the price of any fossil fuel.
Hydrogen fuel cells are a new way forward; a fuel cell is an electrochemical energy conversion device. It converts the chemicals in it to hydrogen-oxygen and water and produces electricity; in this way, it causes no pollution. There is a constant flow of chemicals; the cell never dies. Alternatives to polluting fossil fuels are being looked into and are an upcoming field as researchers are only beginning to see how pollution is truly effecting our environment.
Conclusion. Crude oil, amongst other things, is something we, as teens, take for granted. We do not think about how it is affecting the planet. We only care that it helps to take us where we need to go. In writing this paper, I have realized how much money is put into producing this finite resource, and I am more aware of the processes used to refine crude oil and why hydrocarbons are so crucial in today’s world. I have also drawn from this product how dependant the world is on crude oil and fossil fuels in general. The science behind this topic has made this an exciting theme to cover.
- http://www.naturalgas.org/overview/background.asp http://en.wikipedia.org/wiki/Petroleum
- www.bbc.co.uk-( fractional distillation image)
- www.Wikipedia.com-search: oil refinery, petroleum
- www.google.com-images-crude oil, fractional distillation
- http://www.dit.ie/DIT/science/chemistry/rsccomp/competition00/distillation/topframe.html-( BP data table)
- www.howstuffworks.com-crude oil
- How things work – national geographic: john Langone
- Explaining chemical processes 4th edition: Kenneth A. Solen