Upgrading of crude oil in supercritical water: A five-lumped kinetic model

•A five-lumped kinetic model was built to represent the reaction pathway.•The model coincides well with experimental data.•The free radical mechanism processes on the surface of asphaltenes droplets.•Very few of coke are generated in SCW system.

Experiments on upgrading crude oil in supercritical water (SCW) were conducted in an autoclave to investigate the influence of reaction conditions on pyrolysis and a five-lumped kinetic model was established. It can be illustrated that coke is mainly generated by asphaltenes and changing phase structure of the reaction system and enlarging the specific surface area of asphaltenes droplets via increasing water density or water-oil ratio can enhance the output of light components and suppress the formation of coke. The five-lumped kinetic model consists of saturates, aromatics, resins, asphaltenes, coke and coincides well with the experimental data.