Establish catalyst circulation between the two reactors
Thread Content
When the main air supply is cut off or some other event causes the two units to restart the catalyst circulation, the inventory in the stripping section has already been emptied; how can the catalyst circulation be restarted in a safe manner under such conditions? (The storage volume in the stripping section is now empty; if a pressure difference is created to enable catalyst circulation, how can it be prevented that large amounts of air enter the downstream distillation system?)
This post was last edited by Jubao Pen Yi on 2019-10-14 at 12:04. The reserve in the stripping section is empty; one can monitor the pressure drop across the raw material slide valve. If the pressure drop is within the normal range, a reverse pressure difference can be created to establish catalyst circulation. If there is no pressure drop in the regenerating spool valve, or if a pressure drop does occur, the reaction pressure must be 10 KPa higher than the regeneration pressure in order to establish catalyst circulation. Make sure to change the fluidization loosening points for the regenerated and raw inclined tubes to steam. Return to it once the catalyst circulation is normal.
Is it easy to establish a circulation using negative pressure?
The reactor is empty; it’s necessary to transfer catalyst from the regenerator to the reactor. Isn’t this operation the same as when starting up?
At the start of operation, we first conduct fluidization experiments with the two reactors, establishing a certain reserve in the stripping section; thereafter, the large blind flanges for oil and gas are removed to enable fractionation, thus setting up various cycles in the fractionation tower, with no risk of air entering the system. When the reserves in such a stripping section are exhausted and there is oil and gas inside the distillation tower, could establishing a circulation system lead to air entering the distillation system, thereby creating safety hazards?
Well, what you mentioned is indeed a problem! However, during startup, steam is used in the reactor to displace air; under normal conditions, there should be very little air present. So even if some air is present, as long as there is steam protection in place, this situation should be avoidable!
A large amount of air won’t enter from the back in this case. Just perform normal extrusion