# scrubbing column with retention 'flaps'



## samuel-a (Nov 24, 2011)

I'm thinking on building a fixed scrubbing columns for Nitric leachs and AR (seperatly) where the sparger providing large surface area of the gasses and the retention will be provided by 'fleps' (or some sort of spirl design). 
The column is of course filled with NaOH solution.




I would imagine that the bubbles will grow as they move up...
I guess, a trial and error needed for sure, but would like to hear opinions before i even get started.
Thanks.


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## butcher (Nov 24, 2011)

I like the Idea, The fine bubbles of gasses at the entrance tube should help also, maybe some kind of large lava rock bubbling stone, or several the gases has to get through?


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## samuel-a (Nov 24, 2011)

butcher said:


> or several the gases has to get through?



butcher

I'm not sure i understood the question...


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## butcher (Nov 24, 2011)

Samuel, 
sorry,
It was not really a question, (my bad grammar, and bad communication skills) but how I tried to state what I was thinking, maybe if I try and say it a different way:

I like the Idea, The fine bubbles of gasses at the entrance tube should help also, maybe some kind of large lava rock bubbling stone, or several the gases has to get through?

I like your Idea, the very small bubbles forming, where the tube from the reaction vessel enters the scrubber, these small bubbles should help the solution absorb the gases,(more surface area for absorption). Maybe you could use some type of lava rock as a bubbler stone (? I do not know), maybe you could have another shelf with a lava rock or something similar (so when small bubbles join together, they will have to pass through this (bubbler stone shelf ) volcanic rock and again make small bubbles while traveling their way up in the solution (? Again I am not sure if this would work?)

The question mark at the end (was I am not sure).


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## Geo (Nov 25, 2011)

scintillated bubblers are made of glass.im not sure about what sizes they come in as ive only seen the kind that goes in small fish tanks but i assume they make large types as well.if the concern is slowing the bubbles down on their way up you may add fiberglass wall insulation matting at a couple of layers so the bubbles have to pass through this barrier,that should slow them down quite a bit.


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## glondor (Nov 25, 2011)

Interesting idea. A few questions tho to clarify for me. How do you get the nox fumes into the scrubber. If it is a sealed system with the reactor, would you have to worry about reflux? If it is a sealed system pressure will push fumes out to the scrubber, however at some point that sealed system will want to pull something back. Will a blower "pull" the fumes from the reactor thru the scrubber liquid? Can you create a low enough pressure inside the scrubber to do this? Are you drawing vacuum from a sealed system or an open fume hood. 

On another note what do you think you might make it with? I like the simplicity of the design but wonder if baffles would require you to have a very large blower to overcome their resistance to air flow. 8)


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## 4metals (Nov 25, 2011)

The retention time is increased by the flaps and that is a good thing, but this type of scrubbing is done by pulling fume through a water column so the CFM is limited by the size of the eductor. Big eductors, and the big pumps to drive them, get very expensive, to the point where a conventional packed tower with a corrosion resistant blower will be cheaper per CFM.


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## samuel-a (Nov 25, 2011)

Thanks guys



glondor said:


> If it is a sealed system with the reactor, would you have to worry about reflux?



Yes, there will be a condenser set vertically that will connect to the inlet. 

My plan for this column, is to be no higher then 1 1/2 ft and indeed to connect it to an eductor (set on a faucet, i failed to write it down in my drawing) as 4metals suggested in previous posts.
Togather with the + pressure produced from the reaction, i rekon it should support bubbling. But don't know for sure, i guess only experience will tell.

The plan is to fix everything to the wall (the condenser, scrubber column and piping) to creat one place to work hot reactions, outside of the hood.


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## 4metals (Nov 25, 2011)

Rather than pressurize (even slightly) a glass reactor, I prefer to add a vent to the reactor. Usually it is a small stopcock which can be cracked ever so slightly to allow the eductor to pull through the reactor and into the scrubber. This way you never have positive pressure in the vessel and with a slightly cracked stopcock, you will not build up negative pressure either. Tapered necks don't handle positive pressure well, ball and sockets are clamped and do better but get costly.


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## samuel-a (Nov 26, 2011)

4metals said:


> Rather than pressurize (even slightly) a glass reactor, I prefer to add a vent to the reactor. Usually it is a small stopcock which can be cracked ever so slightly to allow the eductor to pull through the reactor and into the scrubber. This way you never have positive pressure in the vessel and with a slightly cracked stopcock, you will not build up negative pressure either. Tapered necks don't handle positive pressure well, ball and sockets are clamped and do better but get costly.



Thanks for the input.


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