The temperature at one point in the dilute phase of the catalytic regenerator is high
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For a 1.4 million-ton catalytic cracking unit, there are two temperature points at the inlet of the regenerator’s dilute-phase cyclone; one of these points often reaches a temperature as high as 730 degrees, while the other reaches 690 degrees. The point with the higher temperature is located near the external inlet and the return pipe. There is leakage in the regenerator, and less than 2% of the catalyst passes through the 0-40 mesh sieve. Experts, please analyze the reasons
Is the external heat-fluidization air volume normal? Is the catalyst reserve also normal?
The external fluidization air volume is normally around 4000. The amount of catalyst stored is not normal; it fluctuates on its own – it doesn’t increase over time, then suddenly increases by several tons, only to drop by several tons again after some time
I think it might be due to the low reserve level, which results in an excessively high line speed; there might also be some deviation in the flow!
This post was last edited by Ma Boyou on 2021-3-9 at 09:18. A break in the main air distribution pipe or large holes formed due to localized overheating of the distribution plate can cause deviation in the distribution of main air. It is very likely that the blind cover of the straight section of the main air distribution pipe has fallen off, allowing main air to flow directly, which leads to fluctuations in the stored amount and overheating in the dilute phase.
New blind covers were installed during the maintenance of the main air distribution ducts; they are secured with bolts, as there is a risk that the bolts might loosen and fall off
Generally, the blind covers for the main air ducts are welded, while the flange cover bolts are tightened; in a fluidized state, this causes catalyst swirl to occur in the gaps between the flanges, resulting in severe erosion of the bolts. It’s very likely that this bolt has broken, causing the blind cover to fall off.