(20b) Coke Quenching in the Delayed Coking Process

Proper quenching of the coke bed in the delayed coking process is vital to safe operation. Numerous refinery accidents and near accidents have resulted from "hot spots" in the coke bed due to improper quenching. We present here experimental results on steam stripping and water quenching in a delayed coking pilot unit system with a three inch diameter coke drum. Results show the dependence of coke cooling profiles on the coke density and water feed rates. A model is presented that predicts the coke bed temperature profile over time and thus the optimum quenching conditions. The effect of coke morphology (shot vs. sponge) and the quenching of beds with mixed/varying coke morphology are shown and discussed.