Crude Oil

Once the site has been selected, and legal as well as environmental issues have been dealt with, the crew begins to prepare for drilling. Crude Oil is mostly located at or near sea as it is composed of tiny marine animals and plants. This is the main reason as to why a production platform, also known was an oil rig is set up. An oil rig is basically a huge offshore platform with the facilities to drill wells, extract and process oil and natural gas, as well as export the products to shore. A hole is drilled into the reservoir rock and lined with steel. The oil is pumped up through it. Some wells are also connected to a platform by flow lines and by umbilical connections, allowing extract oil from several wells simultaneously. These are called subsea wells.

Subsea System

Once an oil rig has been set up, production will run a tireless twenty-four hours a day. Workers will get two weeks on the platform and then a following two week break. On the platform workers are split into two on to take place from groups, taking turns in working twelve hours a day. Production will continue till there simply is nothing left to extract. In some cases this can take whole twenty years.

Once in the process of being extract from its source Crude Oil is continuously transported to a nearby oil refinery, via pipes that either pump oil to a tanker terminal or all the way ashore, which is one of the main reasons as to why oil refineries are often located near seas another reason is because of the huge amount of steam used during the process of cracking hydrocarbons. An oil refinary is an industrial process plant where Crude Oil is processed and refined into more useful substances, such as gasoline, diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas. The oldest thus most common way of separating Crude Oil into various different more useful substances (fractions) is through the process of fractional distillation, although newer techniques have been developed including the method of Chemical Processing, which allows further breakdown of hydrocarbons possible.

Components of Crude Oil have different sizes, weights and boiling temperatures. Ergo, the first step for Crude Oil in a refinery is to be broken down into smaller less complex hydrocarbons. Fractional distillation is used as it works on that exact principle, that different substances have different boiling and melting points:

1. The Crude Oil is heated to a high temperature, about 600 degrees Celsius. This is usually done with a tremendously high pressure of steam.
2. The Crude Oil eventually boils, causing vapors to form.
3. The vapor enters the bottom of a long column, known as the fractional distillation column that is filled with trays. The trays have small holes in them that allow the vapors to pass through, and yet help collect liquids at various heights in the column depending on when the substance condenses.
4. The vapor slowly begins to rise
5. As the vapor rises it begins to cool, as there is a temperature difference in the fractional distillation column (hot at the bottom cool towards the top)
6. When the vapor reaches a height of which is consistent to its boiling point, it will begin to condence, thus eventually form a liquid.
7. The trays collect the condensed liquid
8. The trays go to other areas for further chemical processing.

After the process of Fractional Distillation, the Crude Oil has successfully been separated into fractions. However, the fractions all need to undergo further treatment before they can be used. This is where the process of Cracking takes place. Long-chain hydrocarbons are heated and vaporized, the vapor is usually passed over a hot catalyst to speed things up and eventually thermal decomposition takes place. Cracking is one of the most important reactions in the oil industry for two main reasons. Firstly it lets you turn long-chain molecules into shorter more useful ones, and secondly it always produces double bonds between carbon atoms. Double bonds make compounds able to react with other compounds, in this case to make substances such as plastic from the small fractions.

Here is an example of a Cracking Reaction (Thermal Decomposition)

Decane (C10H22)        540o Catalyst        Pentane (C5H12) + Propene (C3H6) + Ethene (C2H4)

What are the good and bad sides of the use of Crude Oil in society? How are societies benefitted and harmed by the use of oil?

Everything that is made of plastic is made of crude oil. Almost every form of transportation uses oil in some kind of form, it powers most of the equipment that was used to build almost every building within the last couple of decades. It also is used to make certain components of fertilizers which allow us to feed billions of human beings around the globe. The oil industry employs millions of people and Crude Oil itself can potentially help develop developing countries, Dubai being a great example.

On the other hand the use and production of Crude Oil is extremely harmful against the environment. Power stations, as well as cars produce dangerous gases such as Carbon dioxide, Sulphur dioxide, nitrogen oxides and carbon monoxide. Carbon dioxide contributes to the theory of global warming, and sulphur dioxide mixes with water vapors in the sky to form acid rain. Carbon monoxide is also very dangerous as it can’t be seen or smelled, but mainly because of the fact that it mixes with haemoglobin in your lungs thus kills you in a short period of time. Oil leaks and spills can destroy ecosystems, and the extraction of Crude Oil requires lots of space, a problem solved by chopping down the rainforest. Another mayor problem with crude oil is the fact that it is an unrenewable source, scientists predict that we only have enough Crude Oil for about 30-40 years.

What will we do when the non-renewable sources of oil will dry out? What alternatives do we have?

Although technically Crude Oil is a renewable source it isn’t because of the fact that we are using it at a much faster rate than nature can is capable of producing it. As I mentioned scientists have estimated that if we keep using Crude Oil in such high quantities we only enough crude oil for about 30-40 years, which means that we have to come up with an alternative fast.

A possibility would be to rely on coal, which too is a non-renewable source but is has been predicted that there is enough of it for a good 300 years. But what will we do then, well hopefully we will have had the time to fully develop solar, wind and other types of renewable energy.

Right now scientists are trying to figure out other possibilities, some of which used the idead of compressed hydrogen as a fuel.  

Bibliography

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• Textbook: New Coordinated science 3rd Edition Chemistry for Higher Tier
• Class Notes

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