Kinetic Model for the Deep-Severity Thermal Reaction in the Coke Drum of Delayed Coking

Abstract

The coke drum is the main reactor of the delayed coking process, in which the deep-severity thermal reaction of heavy oil takes place. To simulate the product distribution in this reactor, a kinetic model for the deep-severity thermal reaction was developed on the basis of the experimental data of a vacuum residuum in a microbatch reactor at 430–490 °C. The model-predicted results agree well with the experimental values. The ratio of the cracking gas/light distillate rate constant increases with the reaction temperature. Both the primary condensation/cracking rate constant and the secondary condensation/cracking rate constant increase with the reaction temperature. It means that the lower reaction temperature is advantageous to increase the distillate yield at the same reaction severity. Furthermore, a practical transformation method was presented to improve the suitability of this model. The comparison results indicated that this transformation method is available for the kinetic model in this research. ...