# Will it control NOx



## jeneje (Jun 30, 2012)

I need input on this design i made today before i test it in the morning. After thinking about the stupid remark i made to chickenhawk about using a wet cloth :roll: not smart at all and yes i do no better. I wanted to design something cheap that all members can afford to help with the NOx we make during the processing of base metals. Here is what i came up with and any suggestion welcome.
I went to walmart and got a one gallon ball mason jar made of glass cost 15.00 the top has a plastic seal and the cap is stainless. I then took two five gallons buckets, one i cut the botton off 2" down the side, so the main bucket will site down in it. Next i drilled an 11/16 hole in the side of the main bucket for the pvc piping to come through. Then i cut an hole in the top of the jar also for the piping to fit into. 
I have posted the pictures of what it looks like and if it works i will post all the fitting and tools needed to make this but first i wanted to try so no one will get hurt.
The main container will hold a lye solution for the NOx to bubble in as the pressure increases in the jar it should force the gas to the container. The top will have a heavy cloth on it and then i used one of my classifiers that will set down in the bucket to hold a packing bed. I will try it with charcoal first if it works i would recommend limestone chips or maybe wood ash.
Thanks in advance for any help.
Ken


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## glondor (Jun 30, 2012)

You are using the mason jar as the reactor? Make sure there is no possibility for reflux. Do not heat the mason jar. Be prepared for the mason jar to break at the peak of a reaction. I think your retention time may be too low to be effective. I would not use it indoors. Be safe.


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## jeneje (Jun 30, 2012)

glondor said:


> You are using the mason jar as the reactor? Make sure there is no possibility for reflux. Do not heat the mason jar. Be prepared for the mason jar to break at the peak of a reaction. I think your retention time may be too low to be effective. I would not use it indoors. Be safe.


glondor i am testing it outside, what i am looking for is a pryex 1 gallon jar but have not found one yet still looking. I dont think reflux will be an issue but will be careful there, My main concern is if the jar can hold the pressure created by the gas. I would feel better with a thicker reactor. Also i am wondering if the fumes will travel into the solution and have enought pressure to bubble.
Ken


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## jmdlcar (Jun 30, 2012)

Hi,

You should have got 1 gallon pickle jar it would have cost less then $5.00 Wal-Mart and you could have eat the pickle and go to the bakery and ask for a 2.5 gallon plastic bucket with lid for free at Wal-Mart. I think the jar will fit in the bucket for safety if the jar breaks.

Jack


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## samuel-a (Jul 1, 2012)

jeneje 

No offence mate, but this is too crude.
First, You would want your reaction vessel to be of good quality glass, mason jar or any other jar will not provide that. As well as the metallic cap... it will corrode in case you want to run AR.

I'm afraid there won't be enough retention time for the NO/NO2 to scrub, the result would basically be like running the reaction without this contraption.

The pressure in the reaction vessel is directly linked to how deep the gas outlet is submerged in the solution, it diameter and the reaction speed. These are issues which should not be left out. You may find that you need vaccum to aid the overall scrubbing process and also to protect from back flow.

There are many posts on the subject made by very proffesional members, mainly 4metals, have you checked them out yet?


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## jeneje (Jul 1, 2012)

Well, i will know shortly if it works or not.
Ken


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## jeneje (Jul 1, 2012)

Ok, here are pic of the test, i used 1/2 cup of low grade pins, 2 and half gallons of water mixed with 3oz of lye, in the reactor i a 2 to 1 mix of HNO3 2parts HNO3 to 1part water. It is worth noting that a tighter seal on the reactor will be needed but very little escaped from around the seal.
Thanks for all the advice 
Ken
edited; i done this test and used a extreme amount of HNO3 I was in no danger i had a full face mask with supplied air. This was only a test to see where improvements were needed,


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## Moo (Jul 2, 2012)

Not to hijack the thread, I too am working on a design to control & scrub nitric fumes, using glassware will post picture of it later on I tested how it fared holding fumes under extreme heat by generating HCL and it went great, perhaps you can use these ideas yourself.
Heres mine for what its worth  basically its just a variation of the method nerdrage uses on youtube for making hcl, [youtube]http://www.youtube.com/watch?v=YGjd7xxTuZw[/youtube] I am the worst at drawing in the world I wreckin so ill try to explain it in words. All Glass setup with tapered joints

Basically have a erlenmeyer flask as the reaction vessel attached to a claisen head with one neck attached to an addition funnel for adding nitric when required, the other connected to a vigruex column, fumes can travel up through the column and condense rejuvenating the nitric as it falls back down any gas that gets to the top of the funnel is then led into the nipple of a recieving adapter that is attached to another flask (this is what will hold any back flow) the gas flows through the adapter nipple down the outer tube and then back up through the inner tube that is then led out through chem resist tubing into a dreschel bottle and bubbled into the solution of NaOh for scrubbing from there I am yet to decide if to add another flask or not should be ok on a small scale and if done outdoors as it may break.

Initially I was just going to go with a fractional distallation setup using a condenser but it turns out in Australia now that you have to sign a end user dec with its intended use etc and have it available to the cops, due to the few bad apples that have used these things for making harmful chemicals, if you know what I mean.


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## jeneje (Jul 2, 2012)

Moo said:


> Not to hijack the thread, I too am working on a design to control & scrub nitric fumes, using glassware will post picture of it later on I tested how it fared holding fumes under extreme heat by generating HCL and it went great, perhaps you can use these ideas yourself.


Thanks Moo, any ideas i am open too, after the dust to say settled i took off the top of the bucket and the lye solution worked great, also there were some residue of NOx left in the glass but i think i figured out how to solve that prolbem. I found a 3/4" Y that i can use to attach a small air line from a fish pump to push any residue to the bucket. I think the test went quite well for my contraption and i even got some gold foils from it. :mrgreen: 
Ken


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## Lobby (Jul 2, 2012)

The term for the issue you're asking about is "_mass transfer_." In other words, are you giving the gasses leaving your reactor enough opportunity to contact the water / caustic solution so that the NOx fumes will react with it?

The answer ought to be "no," but there are reasons why your system might work: the amount of NOx that you have is so low, and it's volumetric flow rate is also correspondingly low, that the NOX WILL absorb into the solution.

That's what may be happening in your case.


Here's why is should not work (the only reason I'm posting this is in case someone wants to try this in a larger scale):

- the diameter of the pipe under the water / caustic mix is too large, making bubbles that are too big. Large bubbles have crappy mass transfer.

- the height of the water solution is too low. The bubbles will escape too rapidly

- the path the bubbles take through the solution is wide open. There's no tortuosity in the path. Some sort of mass transfer aids (column packing) would help this.


If a chemical engineer were to design a "scrubber," he'd:

- make sure the reactor could handle the pressure drop induced by the scrubber

- make the scrubber a cylindrical vessel, with column packing

- the NOx gasses would enter the bottom, and would pass through the packing on their way out

- the water/ caustic solution would be recirculated with a small pump from the bottom to the top of the scrubber, where it would flow counter current to the gas

- if you really wanted to get fancy, you'd install a pH probe in the solution somewhere to make sure you don't go acidic


Of course, you'd need to perform all sorts of calculations to make sure the packing you selected (and the tower diameter) were appropriate to the water flow you select and the system's gas flowrate.

Ah, chemical engineering.....


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## jeneje (Jul 2, 2012)

Lobby said:


> The term for the issue you're asking about is "_mass transfer_." In other words, are you giving the gasses leaving your reactor enough opportunity to contact the water / caustic solution so that the NOx fumes will react with it?
> 
> The answer ought to be "no," but there are reasons why your system might work: the amount of NOx that you have is so low, and it's volumetric flow rate is also correspondingly low, that the NOX WILL absorb into the solution.
> 
> ...


ummm, to do all that you mentioned - how much in dollars$ do you think it cost?


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## NobleMetalWorks (Jul 2, 2012)

It would be easier, and actually work, if you used Hoke's method with a bell jar.

It's simple and it doesn't work real efficiently but it does work. Since you are conducting your reaction in a jar you should be able to find the parts you need to make it work fairly easy.

Also give Moo's design a chance, if it's what I think it is, it should work on a small scale.

Scott


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## goldenchild (Jul 2, 2012)

I would reduce the amount of neutralizing liquid some and put some kind of scrubbing medium atop the solution. Wiffle balls or 2 liter bottle rings come to mind


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## BAMGOLD (Jul 2, 2012)

From the day's of Ethanol Reflux (Bokakob) Stills, I would suggest looking at some packing such as they use, they sell it rather cheap and it's very effective in certain circumstances, as I'm very new to all of this, just tell me I'm an idiot, but it is a place to look...

Here is 1 example http://www.milehidistilling.com/products/ceramic-raschig-rings-1-4-inch-6-x-6mm-1-liter.html

1/4 inch Ceramic Raschig Rings







EDIT: What would happens if you used something like Copper mesh packing? Would it just get eaten up I imagine?


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## Dlog Renim (Jul 2, 2012)

here what i saw so far on here..

you can put marble (kids one), or do like me, i went to the car scrap yard and asked the owner if i could brake side window on car ready for the press. The man told me to have fun and be careful. (Side window brake in little square(tempered)).

i saw some one who putted (looking plastic) ball with cut in it (cant tell you the name they use that for aquarium) i looked for some but to expensive for me.

and all those spherical media (ceramic, volcanic .. name it)

On the one i am making (scrubber which i dint try yet because it is not done) i went for 3 size of media (so the bubble must work hard through all layer of media).. my caustic solution is in a 3 inches pipe by about 5 feet tall shaped like a U.. So in the middle i have very small media (maybe 4 time like a grain of sand) in that U on each side i added medium media up to about half way to top.. and finely fill up the rest with my larger media..

My air intake start on left side of the U at the top.. have to travel down the pipe from big media (top) to small media (bottom) and go back up in the medium and small media again on the right side

I did some try with only water and cigarette smoke (i know not the best but better than nothing) and from what i saw.. from all the different media set up this one worked real good with the U shape

But in my case i use a ventury suction pump (run with water to build suction) and run the fume in this.. so my way to do not the same.. You build some pressure to make the fumes ... but i still think, to catch more smoke in your caustic liquid, a media set up might help.. 

also the idea for the piping.. In the solution you should try to smaller the pipe size and put a cap at the end and drill really small hole.. so instead of big bubble at the exit, you will have smaller bubble which will travel slower to the top of your caustic solution.


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## Lobby (Jul 3, 2012)

jeneje said:


> ummm, to do all that you mentioned - how much in dollars$ do you think it cost?



Heck, I don't know. It depends on what question you're asking:

- "can you help me figure out to make my little glassware gold reactor / scrubber work better?" 

or,

- "can you design a small backyard scrubber system suitable for a hobbyist gold refiner?"

I think what you want is B). But that's the expensive one. And there are pics and schematic drawings of this very thing here on GRF....


Me? I'd find some 4" PVC piping for the scrubber, fill it with those ceramic cylinder packing in a prior post. Aw, forget it. There's just too many calcs to do:

- what solution flowrate do you need to both not flood the tower and to adequately wet the packing?

- what pump do you get? Volumetric flowrate, head, and materials of construction?

- how do you design and what do you make the liquid distributors out of?

on, and on, and on... My HP calculator stars quivering as I think of all this.


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