Getting oil out of the ground is one thing. Turning that oil into a product that we can use in our daily lives is a whole other ball game. In this article we will take a look at the oil refining process and see how this natural resource that has caused so much controversy of late is turned from crude oil into something usable. Refining is often referred to as the ‘downstream’ part of the oil production process.
When crude oil is extracted from the ground, it is sent over to a refinery to be processed. In the refinery it will go through three basic steps: separation, conversion, and treatment. We will take a look at each of these in turn later on. From one barrel of crude oil, a number of different every day products can be created. However, the main focus of a refinery is to convert oil into transportation fuel. Petrol, diesel, and jet fuel make up the bulk of what comes out of a refinery.
Separation
Separation is the first stage of the refining process. This procedure involves piping the unrefined oil through hot furnaces into a distillation unit. The parts of the crude oil that make it into the distillation unit are then separated into components according to their boiling points. For example, butane and gasoline are at the higher end due to their low boiling points, and heavy gas oil and fuel oil are at the bottom because they have much higher boiling points. These components are called fractions. The lightest fractions rise to the top of the distillation tower, while the heavier fractions sink to the bottom.
Conversion
Once the crude oil has been separated into its different fractions, the conversion process begins. Heavy components that have sunk to the bottom of the distillation tower are made lighter in order to be of a higher market value. One way of doing this is by ‘cracking’ the heavy hydrocarbon molecules so that they form lighter ones. By the end of the cracking you will have the basis for varying grades of oil, which will then need to be treated. Other ways of converting the components include alkylation and reforming. These methods are different to cracking and add value to molecules by rearranging them as opposed to splitting them.
Treatment
The final part of the refining process is the treatment. This puts the finishing touches to the oil and gets it ready to be sold. To make gasoline, technicians must delicately combine a range of streams from the processing unit to get the blend just right. Treatment of the oil also involves removing any impurities and non-hydrocarbons from the mix as these could adversely affect the efficiency and performance of the final product.
Once the gasoline or diesel or whatever it is that has been created is in its final form, it must be stored in a tank farm near the refinery until it is ready to be transported to its purchaser. Trucks, pipelines, freight ships and a variety of other transportation methods are put in place to get the products from point A to B.
As you can see, the impact of oil goes far beyond simply drilling wells and pumping it out of the ground. There is a complex process that must be undertaken to get that oil into something usable.
