Bottom Head Removal to Shorten Coking Cycle
The decoking crew should begin unbolting the bottom head while the drum is still draining. Leaving every third bolt in place, the drum depressured and mostly drained, keeps the head secured. As soon as the worker unbolting the head sees the flow of water diminish from the dump line, shown in Figure 2-9, he should finish unbolting the head while a co-worker disconnects the resid feed line. Using this procedure, the bottom head can be removed within 20 minutes after the water stops draining from the drum.
Next, the skirt, or telescoping chute, connecting the choke chute to the drum’s bottom flange is hoisted into place and bolted up. While this step—which should take 10 minutes—is proceeding, the third member of the decoking crew should be lining up the cutting water system and lowering the drillstem with the pilot head attached into the top of the drum. The coke is now ready to cut, and the full decoking crew should assemble on the cutting deck.
Categories: Process Troubleshooting
Tags: bottom head
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