Catalytic cracking unit start-up and shutdown flushing fluid
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During the start-up and shutdown processes of catalytic cracking units, catalyst loss has occurred on multiple occasions, and it has been impossible to determine the optimal operating parameters to prevent such loss. The specific reasons are unclear; factors such as air volume, pressure, centrifuge linear speed, and catalyst particle size all play a role. Could you provide some specific guidelines or practical solutions?
Your question is described too simply – are the leaking substances coming from the settler or from the regenerator? Which phase is in operation during startup and shutdown? Operation data during running? If you ask others like this, even if they give a general answer, it won’t be of any help to you! ! !
Leakage during startup occurs mainly before the charging and sealing of the centrifugal leg and during the stage of injecting combustion oil, while leakage during shutdown occurs mainly after material cutting, during the burning due to injection of combustion oil, and during the material unloading stage. The procedures for reducing agent leakage are clearly written out, isn’t that great? :lol
At the start of operation, feeding began, and the material flowed out through the regenerator flue; once a certain amount had accumulated, the double-acting slide valve was opened, allowing the catalyst to flow into the lift pipe. From there, it flowed through the oil and gas pipelines into the distillation tower. The data related to this material flow were controlled by the operators based on experience, so no reliable references can be provided.
It is normal for the additive to flow into the distillation system while the regenerator’s inventory has not yet had its material leg flap valves sealed; however, it is abnormal if the additive flows into that system once fluidization begins in both units after the additive has been added to the regenerator. If this occurs after a shutdown for maintenance and the plant is restarted, then equipment problems can be ruled out, and the issue must lie in the operation procedures. Speaking of which, didn’t you first run a fluidization test to ensure there were no issues, and only then remove the blind flanges for reaction and distillation?
There is no abnormal leakage of catalyst during its fluidization; the main period of leakage occurs when the feed oil is introduced and the reaction starts, and the primary location of such leakage is within the regenerator
There is no abnormal leakage of catalyst during its fluidization; the main period of leakage occurs when the feed oil is introduced and the reaction starts, and the primary location of such leakage is within the regenerator
The regenerator shouldn’t lose fluid! Excluding equipment failures, could it be that the main air flow rate is too high? It might be possible to reduce this flow rate and adjust the regenerator pressure to see if that helps! ! !
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Check whether there is water present in your raw materials and steam, etc., which might be causing thermal shock of the catalyst