Visbreaking, another form of thermal cracking, was developed in the late 1930s to produce moredesirable and valuable products.

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

Visbreaking is thermal cracking, when the vacuum residue is less viscous and it can then be usedto produce valuable products.