Thermal Cracking – continued.

Visbreaking Process

The figure provided here illustrates a schematic diagram for a visbreaking process (a type of thermal cracking process).

Visbreaking, a mild form of thermal cracking, significantly lowers the viscosity of heavy crude-oil residue without affecting the boiling point range.

Residual from the atmospheric distillation tower is heated to 800- 950 F (425-510 deg C) at atmospheric pressure. This causes mild cracking to occur in the heater. It is then quenched with cool gas oil to control overcracking, and then flashed in a distillation tower.