Fractional Distillation of Crude Oil

FractionalDistillation of Crude Oil

FractionalDistillation of Crude Oil

Fractionaldistillation is the process of separating a mixture of substanceswith different boiling points. The process is useful in processing ofcrude oil into different petroleum components through petroleumrefinery. Fractional distillation of crude oil produces differentproducts used for various purposes including fuel, syntheticmaterials, and other hydrocarbons (CHM 110, N.D). Gasoline,paraffin, diesel are the most used products of fractionaldistillation of crude oil. Production of gasoline which is the mostuseful product of fractional distillation is enhanced through processof polymerization and cracking to achieve more than 50 percent of itsproduction in every barrel. Pollution from the process is mainly fromproduction of green house gases including carbon monoxide and carbondioxide. This essay looks at the process of fractional distillation,its importance and the pollution issues associated with the process.

Fractionaldistillation of crude oil, normally known as oil refinery is theprocess in which the many compounds in crude petroleum are separated.The basic principle applied in the process is that, the longer thecarbon chain, the greater the temperature at which the component willboil. The crude petroleum is heated at high temperatures changing itinto a gas. The gas is passed through a distillation column whichcools as the height increases. The compounds in the gaseous statecools at different boiling points, and when they cool below theirboiling points, they condense into liquid (Kansha,Kishimoto &amp Tsutsumi, 2012).These liquids are collected at various points of the fractionatingcolumn.

Allthe products of distillation of crude oil have various uses. However,the most useful product from fractional distillation is gasoline. Abarrel of crude oil has about 30 to 40 percent gasoline. However,transportation demands dictate that more than 50 percent of crude oilbe changed into gasoline (CHM 110, N.D). Meeting this demand requiresthat some petroleum fractions be converted into gasoline. This isachieved by cracking a process where large molecules of heavyheating oil are broken down. In addition, reforming or changing themolecular structures of gasoline of low quality molecules or throughpolymerization where larger molecules are formed from smallermolecules. For instance, if pentane is heated up to 500oCthe covalent carbon-carbon bonds start to break during the process ofcracking (Kansha,Kishimoto &amp Tsutsumi, 2012).Most forms of compounds such as alkenes are made during the processof cracking. The formation of alkenes is due to lack of enoughHydrogens to saturate all the bonding positions after the breaking ofthe carbon-carbon bonds.

Source:http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway_pre_2011/carbon_chem/4_crude_oil3.shtml

Themajor fractions from crude oil are demonstrated in the above diagram,with their uses and the behavior in their properties. Gases condenseat the upper end of the fractionating column, liquids at the middleof the column and solids stay at the base (GCSEBitesize N.D).Hydrocarbons with smaller chain are better fuels as compared to thosewith large chains since they are volatile, flow easily and are easyto ignite.

Theprocess of fractional distillation involves the burning of crude oilinto various hydrocarbon compounds. The process involves a lot ofpollution to the environment. During the burning of crude oil, themajor gases produced are green house gases including carbon dioxide(Carbon IV Oxide), carbon monoxide (Carbon II Oxide). Carbon dioxideis produced when hydrocarbons burn in sufficient supply of air.Carbon monoxide on the other hand forms when hydrocarbons burn ininsufficient air supply. Green house gases lead to the creation of ablanket that shields radiation from escaping back to the atmosphere,leading to global warming effects. Besides the green house gases,fractional distillation leads to the production of other gases thatare harmful to the environment (King,2013).The presence of Sulphur traces in crude oil leads to the productionof Sulphur IV Oxide (SO2)gas which is an acidic gas. This gas mixes with rain water to formweak Sulphuric acid (H2SO4)that is corrosive on roof tops and increases soil acidity thusdestroying plants. The high temperatures in the fractionating columnalso enable the nitrogen in the air which is abundant at 78 percentto combine with oxygen and form Nitrogen IV Oxide (NO2)gas. Just like Sulphur IV Oxide, Nitrogen IV Oxide is acidic andleads to formation of Nitric Acid (HNO3)whose acidity causes similar effects like Sulphuric acid (King,2013).

Theother major concern regarding fractional distillation of crude oil isoil spills and disposal of other wastes containing hydrocarbons(Speight,2014).Mostly the process of fractional distillation is carried out in largesee vessels or at sea sides. The spills of oil affect aquatic life.Humans feed on some of sea animals like fish, and when contaminated,they also affect human health.

Conclusively,fractional distillation of crude oil involves the separation of thedifferent oil components in crude oil at various temperatures. Thevarious oil components obtained from the process of fractionaldistillation of oil are used for different purposes. The most desiredproduct of petroleum refinery is gasoline used as fuel. To improveproduction of gasoline, cracking and polymerization are done.Refinery of petroleum causes pollution mainly from production ofgreen house gases like carbon dioxide and carbon monoxide. Othersources of pollution include production of Suplhur dioxide andnitrogen dioxide, as well as oil spills during the process. Toenhance production of useful compounds and reduce pollution, theprocess can be carried out in oil fields rather than on sea shores oron water vessels. The adoption of alternative fuel can also helpreduce pollution from fossil fuel.

References

CHM110 Chemistry and Issues in the Environment. Fractional Distillation.Availablehttp://elmhcx9.elmhurst.edu/~chm/onlcourse/chm110/outlines/distill.htmlAccessed April 29, 2015

Speight,J. G. 2014, Thechemistry and technology of petroleum.CRC press.

King,C. J. 2013, Separationprocesses.Courier Corporation.

Kansha,Y., Kishimoto, A., &amp Tsutsumi, A. 2012, Application of theself-heat recuperation technology to crude oil distillation. Appliedthermal engineering,vol.43,153-157.

GCSEBitesize. N.D.Makingcrude oil useful.Availablehttp://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway_pre_2011/carbon_chem/4_crude_oil3.shtmlAccessed April 29, 2015.

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