(87b) The Processing of Resids and Heavy Oils

Resid upgrading processes continue to increase in importance as the average crude oil continues to become heavier. In addition, the volume of the upgrading of extra heavy oils and bitumens in Venezuela and Alberta, Canada to pipelineable and/or synthetic crude oils continues to rapidly expand. The current resid upgrading technologies will be reviewed: coking (delayed coking, Fluid coking, and Flexicoking), hydroconversion (LC-Fining and H-Oil), and resid catalytic cracking.

Resid conversion is limited by polynuclear aromatic structures in the resid that can be related to hydrogen deficiency. The purpose of coking is to reactively separate these polynuclear aromatic structures as coke along with other catalyst poisons: sulfur, nitrogen, vanadium, and nickel to produce liquids more suitable for catalytic processing: hydrotreating, fluid catalytic cracking, and hydrocracking. By understanding resid molecular structures and coking chemistry one discovers that coking processes can be greatly improved to produce 15 % higher yield of liquids of equal quality and a yield of coke below Conradson carbon residue. This was demonstrated in a laboratory coker that combines separation with coking at minimum vapor residence time and maximum resid/coke residence time. Hydroconversion processes need to practice some of the same principles as high yield coking to achieve even higher potential yield of liquids without costing too much in hydrogen and in catalyst.