Scrubber system

[Islander]

Since I have joined this amazing forum, I have read with much interest everything I can find on controlling the fumes from the various processes. I have come to a design for my own scrubbing system consisting of a series of small containers (5 gallon or 15 gallon containers) filled with the appropriate neutralizing liquid (1.sodium hydroxide and water mix,2.hydrogen peroxide,3.water) each filled with a plastic media for slight obstruction and contact area. A last container containing charcoal to clean up any odors.

Since my chemistry is not up to par and I am trying to learn it, I was looking for any advantages to having 3/4"-1" coral/limestone rock (CaCO3 I believe?) as a media in the container with the plain water, or any of the other liquids. The island where I live is a coral island and this is readily available, and cheap. Any help and advice from the learned ones here would be much appreciated.

 

[4metals]

The best NOx scrubbing comes from peroxide and a mildly caustic mix. The crushed coral should buffer the water and dissolve as the NO2 is converted back to nitric by the peroxide. How are you delivering the fumes to the scrubber setup? Pulling it through by vacuum?

If I remember correctly you are processing jewelry karat gold with aqua regia. Why not suppress fumes with a peroxide glycol mix and make life easier on yourself?

Can you post some pictures of your scrubber?

 

[Anonymous]

I am not sure what volume of air you are pushing, but a simple design is to take some pvc pipe (diameter and length depends on cfm you are pushing with the fan) say 12" diameter, 8 feet tall. Fill with ping pong balls. Equally distribute your solution on top of the balls, and flow the air counter current to the flow of the neutralizing solution. Recirculate your solution from bottom to top.

I had a system like this that was 4' in diameter and 12' tall that worked for 4 fume hoods.

Sodium Hydroxide is what I have used in the past. Your coral will only take the pH to 9. Performance can be improved by crushing coral and heating in a kiln to make Calcium Hydroxide (Lime)

 

[Islander]

Thanks for the quick replies folks!

4Metals,
I fully intend to use the peroxide glycol mix, I would never have known about it were it not for this forum. It should save on nitric acid, big plus for me.
Unfortunately, I have no pics of the scrubber yet as it is still in design mode, but I hope to have it up in the next couple of months. A lot of stuff I have to search locally for, import what I cannot find and build the rest, lol. The fumes will be pulled by vacuum from the fume hood through pvc pipes into the series of scrubbers and vented via pvc pipe up and over the rooftop.

PonyExpress,
I am grateful for the suggestion, I had previously thought of that setup, but height is an issue so I have decided on a series of small scrubbers. I will be using plastic wiffle golf balls instead of ping pong balls, (thought of those too, he he!) that I can reuse in a setup such as you have described at a later date if need be.

Basically, I am looking to scrub most if not all gasses (NOx, Cl, SO2, etc.) in 1 setup just so that I have no worries and to be safe and clean as possible (I am not a person to do what I want and flip everyone else off). I will definitely post again and some pics when it is done as this right now is my main issue. Thanks again!

 

[2002valkyrie]

Basically, I am looking to scrub most if not all gasses (NOx, Cl, SO2, etc.) in 1 setup just so that I have no worries and to be safe and clean as possible (I am not a person to do what I want and flip everyone else off). I will definitely post again and some pics when it is done as this right now is my main issue. Thanks again!

If scrubbing is your goal then being armed with as much knowledge as you can find will help. Here is some fine reading http://www.cheresources.com/hclpicklezz.shtml I hope you find it as useful as I did. 8)