PEP Review 2010-11
Thermal Visbreaking of Vacuum Residue
Published: December 2010
Visbreaking is a mild-liquid phase, controlled thermal cracking process that reduces the viscosity and pour point of atmospheric or vacuum residual oils and produces fuel gas and gasoline blending component by-products. Reducing the viscosity of heavy oils reduces the need to dilute them with light cutter stock in order to meet product specifications.
Today's market forces that favor the visbreaking process include: the decreasing supply of light, sweet crude oil, the increased production of both conventional heavy crude oils (API lower than 20) and tar sand bitumen, along with the need to maximize the conversion of residues to lighter, higher valued products due to increasing crude oil prices. Visbreaking is an economical conversion process that can be implemented relatively rapidly with a short payout time.
We briefly describe developments in the visbreaking process including chemistry and process technology. We determine the process economics for a 23,500 BPSD coil-type visbreaking unit processing vacuum residuum. The main product is combined visbroken vacuum residue and gas oil. Naphtha is an important secondary product.