{"id":104602,"date":"2021-05-12T12:06:26","date_gmt":"2021-05-12T11:06:26","guid":{"rendered":"https:\/\/www.crownoil.co.uk\/?page_id=104602"},"modified":"2025-04-24T14:26:39","modified_gmt":"2025-04-24T13:26:39","slug":"crude-oil-fractional-distillation","status":"publish","type":"page","link":"https:\/\/www.crownoil.co.uk\/guides\/crude-oil-fractional-distillation\/","title":{"rendered":"Fractional Distillation of Crude Oil Guide"},"content":{"rendered":"\n
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Learn How Crude Oil is Refined into Useful Petroleum Products<\/h2>\n\n\n\n

Fractional distillation of crude oil is the process by which we obtain all the various petroleum products that we rely on from crude oil – whether that\u2019s internal combustion engine fuels such as the petrol or diesel<\/a> that fuels our cars\u2019 engines; the gas oil<\/a> powering machinery and furnaces; the jet fuel that fuels aircraft; or domestic and commercial heating oil<\/a> that keeps our homes and workplaces warm.<\/p>\n\n\n\n

In this guide, we\u2019ll go through the diverse spectrum of petroleum products we obtain from crude oil fractional distillation as well as some of their applications.<\/p>\n\n\n\n

You can also learn about some of these fuels in greater technical detail by reading our dedicated fuel specifications guide<\/a>.<\/p>\n\n\n\n

Crown Oil is an oil supplier<\/a>, not an oil refiner, but with more than 75 years in the business, we\u2019re one of the leaders in our industry, and our resident fuel experts have lots of knowledge to share; it\u2019s through sharing our knowledge that you know you can trust us for your fuel and oil needs.<\/p>\n<\/div>\n\n\n\n

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What is crude oil?<\/h2>\n\n\n\n

Crude oil is a naturally occurring viscous black oil. The raw material is made up of complex organic hydrocarbon structures and is formed from living matter that existed many millions of years ago, and in that time that matter has been processed by geological forces to create its current form of black oil. While it is sometimes found at the surface level, crude oil is mostly obtained by drilling for oil in the ground at oil wells on land, and at oil rigs at sea.<\/p>\n\n\n\n

The majority of crude oil is drilled from oil fields in the Middle East, with the Kingdom of Saudi Arabia leading global production. Other major producers are Russia, China, Canada and the US.<\/p>\n\n\n\n

In the UK, crude oil is imported mostly from Norway<\/a> which supplies 40% of all the UK’s crude oil and the US, which supplies 26%. Other countries that export their petroleum to UK refineries in lower amounts include Algeria, Russia, Nigeria, and Saudi Arabia among other countries. Below is a table of where crude oil supplied to the UK came from in 2019:<\/p>\n\n\n\n

Source of UK crude oil imports<\/strong><\/td>Quantity supplied (thousands of tonnes)<\/strong><\/td>Percent of UK’s supply<\/strong><\/td><\/tr><\/thead>
Norway<\/td>17,458<\/td>40%<\/td><\/tr>
United States<\/td>11,405<\/td>26%<\/td><\/tr>
Algeria<\/td>4,325<\/td>10%<\/td><\/tr>
Russia<\/td>3,800<\/td>9%<\/td><\/tr>
Nigeria<\/td>2,777<\/td>6%<\/td><\/tr>
Saudi Arabia<\/td>1,024<\/td>2%<\/td><\/tr>
Libya<\/td>793<\/td>2%<\/td><\/tr>
Canada<\/td>628<\/td>1%<\/td><\/tr>
Netherlands<\/td>484<\/td>1%<\/td><\/tr>
Rest of Africa<\/td>255<\/td>1%<\/td><\/tr>
Egypt<\/td>239<\/td>1%<\/td><\/tr>
Spain<\/td>220<\/td>1%<\/td><\/tr>
Azerbaijan<\/td>181<\/td>0%<\/td><\/tr>
Venezuela<\/td>83<\/td>0%<\/td><\/tr>
Germany<\/td>51<\/td>0%<\/td><\/tr>
Denmark<\/td>33<\/td>0%<\/td><\/tr>
Total<\/strong><\/td>43,756<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n\n\n\n
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What is petroleum?<\/h2>\n\n\n\n

Petroleum is a broad term that refers to both crude oil and petroleum products. Petroleum products are the different hydrocarbon groups that occur within crude oil, and they are obtained through the refinement of crude oil.<\/p>\n<\/div>\n\n\n\n

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What are hydrocarbons in crude oil?<\/h2>\n\n\n\n

Hydrocarbons are chains of carbon and hydrogen that make up all organic material – including crude oil. Along with water, hydrocarbon molecules are the building blocks of life. Crude oil is made up of many different types of hydrocarbon chains all mixed together. When these chains are separated into similar lengths, we have refined the crude oil into useful products.<\/p>\n\n\n\n

A process called fractional distillation is used in oil refineries to separate (as well as join or split) the various lengths of hydrocarbon chains to create different petroleum products from the different distillates.<\/p>\n\n\n\n

More technically…<\/em><\/p>\n\n\n\n

The hydrocarbon chains that constitute petroleum fuel products are a family of hydrocarbons called alkanes<\/a>, or <\/em>paraffins<\/em><\/a>, depending on their size. Alkanes are hydrocarbon chains with the chemical formula C<\/em>n<\/sub><\/em>+H<\/em>2n+2<\/sub><\/em>. Alkanes are stable but versatile, making them safe for use and storage as a range of fuel products.<\/em><\/p>\n\n\n\n

The simplest of these alkanes is a gas, methane, with a chemical makeup of CH<\/em>4<\/sub><\/em> (just one carbon atom); the next largest is ethane (C<\/em>2<\/sub><\/em>H<\/em>6<\/sub><\/em>), propane (C<\/em>3<\/sub><\/em>H<\/em>8<\/sub><\/em>) and butane (C<\/em>4<\/sub><\/em>H<\/em>10<\/sub><\/em>). From there, alkanes are named using Greek numerals to easily identify their structure, as we can see from examples such as pentane (C<\/em>5<\/sub><\/em>H<\/em>12<\/sub><\/em>), hexane (C<\/em>6<\/sub><\/em>H<\/em>14<\/sub><\/em>), heptane (C<\/em>7<\/sub><\/em>H<\/em>16<\/sub><\/em>), octane (C<\/em>8<\/sub><\/em>H<\/em>18<\/sub><\/em>). These alkanes can be hundreds of carbon atoms long.<\/em><\/p>\n\n\n\n

Some alkanes are useful to know about at a technical level, specifically octane and cetane (sometimes called Hexadecane)(C<\/em>16<\/sub><\/em>H<\/em>34<\/sub><\/em>), as they are a measure of the performance of petrol (the octane number) and diesel fuel (the cetane number in <\/em>diesel fuel technical specifications<\/em><\/a>). Alkanes mixtures with a flashpoint of 42<\/em>\u2103<\/em> are grouped as fuel oils.<\/em><\/p>\n\n\n\n

At the same time, there are also alkenes, naphthenes and aromatics present in crude oil, which are used in chemical processes. Alkenes and naphthenes refer to hydrocarbons with a molecular formula of C<\/em>n<\/sub><\/em>H<\/em>2n<\/sub><\/em> but have different structures – alkanes being formed in a chain, and naphthenes in a ring.<\/em><\/p>\n<\/div>\n\n\n\n

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What’s the difference between petroleum and crude oil?<\/h2>\n\n\n\n

While the two can be used interchangeably, when talking about the refinement and production of petroleum products, petroleum is a broad term that includes both crude oil and petroleum products. Crude oil refers to specifically the raw product drilled from the ground.<\/p>\n<\/div>\n\n\n\n

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Fractional distillation and distillates<\/h2>\n\n\n\n

The process through which petroleum is refined is called fractional distillation and occurs in a distillation tower or fractionating column. Outside of the oil industry, fractional distillation is a process used for separating a mixture of two or more fluids of different densities by heating the mixture to the point of boiling. These separated fluids are the \u2018distillates\u2019.<\/p>\n\n\n\n

In the context of oil refining, the distillates are the various products we use, such as petrol or diesel fuels<\/a> or kerosene<\/a>. Each of these products has a different density and form at different stages of the fractionating column \u2013 the least dense gases at the top, and the more dense heavy fuels and bitumen at the bottom.<\/p>\n\n\n\n