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What is The Bitumen Process?

The Bitumen production process can be done in 4 different ways, including solvent deasphalting, air blowing, blending and straight run method. Each of these methods are different from each-other and have their own procedure. But the most common method which is done in almost every refinery is air blowing.

In the post below, we’re going to explain this method. You can check out this detailed infographic which is prepared by the Infinity Galaxy team to understand the air-blowing process in greater detail.

The Bitumen Production Infographic - The ChemEng Student

The Air Blowing Method

To produce the bitumen by air blowing method, the crude oil should be transferred through the pipelines to the distillation tower. The salt and water of the crude oil is removed by the desalter. 

After entering the crude oil in the distillation tower, its components are separated by the trays. Light components evaporate on the higher trays of a distillation tower and the heaviest component will remain in the bottom trays. This heavy material is entered into the vacuum distillation tower and after processing under the vacuum condition, the vacuum bottom will remain. 

This material is the raw material to produce bitumen.

Then it will be transferred to the oxidation or air-blowing unit. In this unit, a mild flow of air is passing through the vacuum bottom. The aim of air blowing is to produce Asphaltene molecules, which increase the viscosity of the bitumen. 

Air blowing results in the generation of Ester molecules which leads to the generation of larger molecules which is called polymerization. 

Oxygen molecules react with the vacuum bottom. This causes the bond between Hydrogen and Carbon atoms to be separated and cyclic molecules to be generated which is called hydrogenation. 

In the air-blowing process, the softening point of bitumen increases and the penetration degree is decreased.

The air blowing is also done in two ways: air rectification and full air blowing.

The bitumen which is produced by these methods is pure bitumen which is penetration-grade bitumen and viscosity-grade bitumen.

The Straight Run Method

Sometimes, the vacuum bottom has the same property as bitumen and its viscosity or penetration is acceptable to use as a binder in road construction. In this situation, it doesn’t need any air-blowing process. It can be used directly in the flexible pavement.

The Solvent Deasphalting Method

One of the bitumen production methods is solvent deasphalting which is used to improve the vacuum bottom properties. In this method, the propane or butane should be added to the vacuum bottom, and then mix well with each other.

At the end of the process, the material which remains is the bitumen.

The Blending Method

In the blending method, the bitumen is produced indirectly. Different types of bitumen are mixed well together, and then a bitumen with the desired properties will be obtained.

At the end of the process, the material which remains is the bitumen.