Hi
I'm working on a design for a gas sparger in a water column, and so far I have not been able to really understand how to design this in correct way.
I have been reading a lot on sparger online (and in Perry hand book edition 7) but i have not fully understand how to get it to work like I want to.
I have attached some pictures of my test stand, this has the following specs:
1 water tank ΓΈ490mm (inside diameter).
1 inlet pipe for the gas (test stand it is air or nitrogen) ΓΈ33,7mm
Water height is 1,5m static water.
Outlet pipe is the same as inlet pipe.
The sparger is designed as a hole plate sparger - mounted on a box that is mounted on the inlet pipe and then submerged to the bottom of the tank.
The specs for the plate is a outside diamter of ΓΈ470
The specs for the gas is the following:
Inlet speed of gas/air is: 15-16m/s
Inlet pressure from the pressure regulator right now is around 1bar
Inlet pressure on the column when running 750lpm is 0,35bar (taken from the manometer)
Volume flow is up to around 50m3/hr or around 750 lpm
I want the outlet speed out of plate in bottom (superficial gas velocity) total out the sparger to be as low as possible, around 1m/s.
Current plate is 1,64m/s -> this is 741 holes, ΓΈ3,5mm evely distrubuted in 13 lines (16 holes inner circle and 98 outer circle)
Here is my problems that I do not know how to calculate on:
- How to get a even distrubution out of all the holes? Right now there is not, i have tried many thing larger holes, different sizes of holes etc. But i'm pretty sure this has something to do with the counter pressure of the sparger plate, and I do not know what i should aim for? So far I have just been testing different plates and patterns to get some understanding of the system.
Only calculating on the total area of all the holes.
The problem is, that at low volume flow only the inner holes are used, and even at the full load I do not see a even distribution out of all the holes. - Second problem, I can see that the water level as a impact on the system, when the column is tilting forward must of the gas is coming out of the holes where the water level is lower. (less static pressure on top of these)
So my question is, does anybody has some advice on how to calculate on such a gas sparger box with a plate on top, what parameters to I need to tweak on?
Is the box design also something I need to look into? The size of this could have an impact on the amount of water that need to get pushed out before the gas is coming out of all the holes I assume?
I'm trying to get this "small" scale to work, so I can make my larger water tank of a diamter of 1,5m - but right now I do fill confident enough to upscale my system and still believe I can get the distrubution to be on as much surface as possible.
Attached Files
Edited by mikkelpoulsen, 12 September 2023 - 07:59 AM.