Nozzle flow rate of the main air distribution plate in the catalytic device
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If the nozzle flow rate on the main air distribution plate of the catalytic unit is increased by reducing the diameter of the nozzles, the pressure drop across this distribution plate becomes greater than before. Could this lead to leakage of material from the regenerator?
Why isn’t anyone answering me? Do everyone’s systems use main air distribution pipes?:'
The reduction in size is also calculated based on reasonable values for the linear velocity of the fluid through the holes and the pressure drop across the distribution plate. If the size is simply reduced, it may be because the original hole diameter was too large; however, in the end, the opening ratio is still determined based on reasonable values for the pressure drop across the distribution plate and the linear velocity. It’s usually around 10 mm; it won’t be too large, otherwise there will be problems.
An increase in flow rate causes the catalysts to wear against each other at the nozzle outlet, resulting in catalyst loss. A nozzle linear speed of 30 m/s might be a hurdle.
Hello! What considerations should be taken into account during the design calculations for the dual-diameter nozzles on the main air distribution plate? Things like outer diameter, length-to-diameter ratio, etc. Thank you!
I can’t answer this question. Let’s give it a try and see if any experts can provide an answer.
We reduced the size of the nozzles in the main air distribution pipe; before making this change, the deviation of the main air flow led to high temperatures in the dilute phase； Please have the design institute modify the system by reducing the size of the nozzles and increasing their number, so that the pressure drop does not increase significantly compared to before, or only increases slightly; furthermore, there should be no leakage from the regenerator.
What should be discussed is the main air distribution plate, not the main air distribution pipe. The key is to check how the number of holes in the main air distribution plate changes when their diameter is reduced, and to see whether the area of the openings or the opening ratio changes. If there are no changes, then there should be no problem. Reducing the opening diameter can improve the main airflow distribution. If the pressure drop across the main air distribution plate increases compared to before the modification, it indicates that the opening area or the opening ratio has decreased, which in turn increases the flow restriction of the main air as it passes through these openings. This may affect the fluidization state of the dense-phase bed to a certain extent, but it is not likely to cause catalyst leakage, as the linear velocity of the air drops once it leaves the distribution plate.