Bitumen Processing Materials

Bitumen obtained mainly from oil. There are two general ways to earn bitumen from oil.
• Distillation
• Aeration
In the first method, depends on food and way of refining, after distillation in the vacuum condition, bitumen with suitable physical characteristics for making roads and industrial applications obtained.

This process involves crude oil being heated to temperatures of between 300 and 350 degrees Celsius, to separate lighter fractions from the non-boiling component, known as an atmospheric residuum. The lighter fractions are drawn off and sent to other refinery units. To remove the last traces of the lighter fractions and avoid thermal transformation of the molecules, the atmospheric residue is then introduced into a vacuum distillation unit, where the pressure reduction lowers boiling temperatures and avoids unwanted thermal cracking of the molecules. The pressure and temperature conditions within the vacuum process determine the hardness of the residuum and, as such, the grade of bitumen produced.

Specific solvents can also be used to separate the lubricant and bitumen components of crude, without changing their chemical structure. Depending on the solvent used – propane or butane – different categories of bitumen can be obtained. By controlling the variables in the vacuum distillation process, bitumens with varying degrees of hardness can be produced.

In the second method, obtained vacuum residue, usually, has very low viscosity and the high degree of penetration of 300-400 mm. The product has low asphaltene, so it is not suitable for making roads in tropical and temperate regions.

Oxidized bitumen has a distinctive consistency at room temperature and a rubbery nature which affects how it responds to stress or imprint. The process of oxidation increases the stiffness and softening point of the bitumen and considerably alters key physical properties. Varying the length of the oxidation or air blowing process varies the extent of the reaction and produces distinctive end products.

To convert bitumen shaped residue to bitumen with suitable physical properties, during a process, heavy molecules like asphaltenes should be added. To do this, air that is combined with different types of gasses like oxygen, nitrogen, co2 etc been pressed by a compressor and it has been injected to a tower containing molten bitumen upper than oc200. The process can be continuous or batch. The so-called semi-aeration process causes the production of semi-blown bitumen with suitable penetration degree and softening point 100/85 or 70/60 which is used in road making and moisture barrier of houses.