Catalytic feed self-preservation problem
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Why is it necessary to rush to close the nozzle feed manual valve after the catalytic feed self-protection action? I hope to get some guidance from all the teachers!
Prevent residual pressure and oil in the pipeline behind the raw oil self-protection valve from entering the riser and causing coking.
After the feed auto-protection system is activated, the circulating fluidization in the two reactors is stopped. If there is leakage from the feed auto-protection valve and the manual valve is not closed, it will cause significant coking in the lift pipe. As a precaution, it is necessary to close the manual valve. Once, during an auto-protection mechanism for the main air supply, the manual valve was not closed either; this posed a risk
One purpose is to prevent coking in the lift pipe; another key reason is to avoid situations where the safety valves and control valves do not function properly, allowing large amounts of oil to enter the lift pipe and contaminate the catalyst. Catalyst contaminated with oil, when fed into the regenerator, can cause yellow smoke to be emitted from the chimney or lead to deflagration or explosion, which is extremely dangerous. In particular, it is essential to ensure that the manual valves for the feed nozzles in the lift pipe are closed in order to maintain safety.
Regarding shutting it down, it has already been explained in detail upstairs. What I want to say is that we don’t shut off the nozzle manual valve right away; instead, we stop the feed pump, as we have experienced the horror of yellow smoke and flash explosions!
Additionally, depending on the design of the plant, some systems cause the two cutters to become fluidized after material is fed, while others do not.
There’s no need to stop the feed pump right away, right? Isn’t the feed switched to circulation when cutting off the feed? So what’s important is to close the feed nozzle.
I’m worried that the self-protecting valve isn’t tight enough and might leak.
I think the main concern is inadequate self-declaration!
What if your nozzle doesn’t seal properly? Do you think it’s closed tight, but actually it’s not? If you’ve seen movies with yellow smoke and explosions, this kind of horror doesn’t just keep going non-stop.