ABSTRACT
Visbreaking is a mild thermal conversion technology that converts some of the residue into lighter products and decreases the viscosity of the residue fraction of the remaining product. It can also be applied for viscosity reduction of the full range oil, as applied to oil sands bitumen to facilitate pipeline transport. Atmospheric residua and vacuum residua are potential feed materials for visbreaking. The products from visbreaking are mainly distillate and an atmospheric residue. There are two types of visbreaking technology: coil visbreakers and coil-and-soaker visbreakers. The main difference in the design with respect to the coil visbreaker is the addition of a soaking drum. Product fractionation after a coil-and-soaker visbreaker is analogous to that after a coil visbreaker. The two main process variants are hydrovisbreaking and hydrogen donor visbreaking. When visbreaking is employed for upgrading of heavy oils and bitumen, conversion may also be defined as a cracking conversion.
