Does the MIP cycle slide valve participate in the feed interlock?
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In the catalytic cracking MIP process unit, when the feed auto-protection function is activated, I wonder whether the raw oil circulation slide valve (from the stripper section to the second reactor zone) is involved in any interlocks. In the design of my unit, this valve is not part of the feed interlocks; instead, it is involved in the interlocks related to the differential pressure between the two reactors. Personally, I do not approve of such a design. I would like to ask everyone: how is the interlock system in your equipment configured?
It needs to be involved in the interlock! It must be included in the interlock just like the regenerative slide valve and the standby slide valve!
From the perspective of our MIP unit, it is involved in feed self-protection. Regarding whether to participate in joint guarantee, it depends on the type of riser. If two lift pipes are used, it is not necessary to participate ； If using one, I think it’s best to participate in joint guarantee.
It certainly needs to be included in the interlock safety system. If it isn’t part of the interlocks, then once the emergency shutdown mechanism is activated and the MIP slide valve fails to close, a large amount of catalyst from the settler will flow into the secondary reaction zone; some of this catalyst will also flow to the bottom of the lift pipe, thereby blocking the orifices in both the lift pipe and the secondary reaction zone
We should get involved; we didn’t include it when designing our device. The workshop regulations require manual shutdown after the self-protection action to prevent a stuck bed
Thank you for the help; this issue is being addressed
Feed self-protection and spool valve self-protection can be activated separately, with the choice depending on the nature of the process accident. If there is a problem with the feed entering the lift pipe, only the feed will be used for self-protection to maintain circulation between the two reactors. Our factory adopts the above solution: the slide valve performs self-protection regeneration, and once the lift valve is fully closed, the circulating slide valve does not participate.