Once the switch has been completed and a small flow of steam (4,000-5,000 Ib/hr for a 20-ft diameter drum) has been estabished, the vapor valve…
One of the frequent causes of extended coke drum cycles is the difficulty in filling the drum with cooling water. Once feed is switched out…
Coke drum overhead vapor valves are massive affairs. Switching a pair of 20-ft diameter drums may require the manipulation of four 18-in. and four 12-in.…
Figure 2-5 shows the valves used during the coking cycle. Prior to switching out of a coke drum, the process operators must be sure that…
Turning around a coke drum is a cooperative effort between the process operators and the decoking crew. It is labor intensive and normally accomplished without…
How long should it take to turn a coke drum around? The elapsed time from when one switches out of a full drum until it…
Whether or not increased recycle ratio reduces shot coke formation is dependent on the composition of the incremental recycle. Recycling 950°F-1,000°F coker gas oil will…
Sulfur causes puffing of the calcined needle coke. Increasing the delayed coker recycle ratio by cutting the heavy coker gas oil end point will make…
Needle-grade coke contains no shot coke. Commercial needle coke is typically produced by charging FCCU slurry oil to the delayed coker. All of the components…
The outside surface of shot coke spheres is coated with a layer of needle coke. The coating gives shot coke its polished-surface appearance.