Separation

• Diesel fuel is separated from crude oil in a long process. Separation is the first step. In this process, heat is applied to crude oil, and it is separated into its various constituents in order of viscosity. This process is known as distillation and takes place when crude oil is passed through a distillation tower. All the heavy viscous liquids settle to the bottom, leaving the lighter particles and gases to settle on the top of the distillation tower.
  
  

Heat Supplied for Separation

• Different components of crude oil have different weights, masses, and boiling points. This process only separates each of these components through fractional distillation. In fractional distillation, heating is applied through high pressure steam and temperatures of about 1112 degrees Fahrenheit or 600 degrees Celsius.
  
  

Conversion

• The process of conversion is very essential as it enhances the value of the components in crude oil. The basic elements of all these components are hydrocarbons. So, conversion also involves re-arranging the existing hydrocarbon bonds to form products which can be used by consumers. The primary aim of conversion is to reduce the hydrocarbon bonds in substances in order to make them worth using. This is done through a rather simple process of hydro cracking.
  
  

Purification

• After the above two processes of separation and conversion, the next comes the process of purification. Purification is primarily performed to remove sulfur from these separated and converted substances. This is done through the process of hydro treating. In this process, every substance is treated with hydrogen under heat and pressure thereby resulting in desulphurised products. This product which is free from sulphur is of high quality is ready to be used.