The issue of inventory in the catalytic cracking stripping section?

High inventory in the stripping section can lead to an excessive residence time of the catalyst, resulting in coking； Too low a reserve can lead to poor stripping efficiency, causing the catalyst to become oil-contaminated. The height of the inventory should preferably not cover the material legs, as this can lead to coking of those legs. Only when coking occurs in the wing valve and as a result the catalyst content in the slurry increases, can the height of the stripping section be increased in order to reduce catalyst loss.

High inventory in the stripping section can lead to an excessive residence time of the catalyst, resulting in coking； Too low a reserve can lead to poor stripping efficiency, causing the catalyst to become oil-contaminated. The height of the inventory should preferably not cover the material legs, as this can lead to coking of those legs. Only when coking occurs in the wing valve and as a result the catalyst content in the slurry increases, can the height of the stripping section be increased in order to reduce catalyst loss. It can’t be that high as the material leg; otherwise, the catalyst will clog the coarse spinner. I think the legs with coarse threading should be set lower; I’m not sure if that’s correct, but it’s important to participate.

It is best to control it according to the design parameters, so that the fluidization effect can be ensured

The outlet of the feed leg can be either a flap valve or an anti-backflow cone; if it is a flap valve, it can be located above the material level, while if it is an anti-backflow cone, it must be buried within the material level.

Appropriately increasing the reserve can improve stripping efficiency

An increased reserve can prolong the residence time of the catalyst in the reactor, resulting in a better stripping effect; conversely, the same is true in reverse. By \"feed leg,\" do you mean the feed leg of a fast separation device equipped with a coarse centrifuge, or rather the feed leg for the mixture obtained after rapid separation of oil, gas, and catalyst by a coarse centrifuge, which then enters several sets of primary or secondary cyclone separators? In that case, the catalyst does not need to cover the material leg, as the flap valve is connected to the material leg; the flap valve must be embedded in the catalyst bed in order to function properly. When the amount of catalyst that falls into the material leg during operation reaches a certain height, and this weight exceeds both the weight of the flap valve itself and the static pressure difference in the catalyst bed, the flap valve opens, allowing the catalyst to fall into the bed. Therefore, if the amount of catalyst stored there is too high, it will affect the efficiency of the centrifuge. In other words, when the amount of catalyst is too high, the pressure drop across the catalyst bed increases, and the height of the catalyst in the material leg also rises before the flap valve can open and allow the catalyst to flow smoothly into the bed. If the amount of catalyst in the material leg is too high, it may cause the catalyst to be carried along with the purified gas stream through the riser pipe of the centrifuge and into the distillation column, thereby affecting the operations in the distillation unit.