Fume scrubber - possibly already in a thread?

[Golddigger1214]

Ok, so I'm sure this will be added to an already existing thread, but I couldn't find exactly what I was searching for.


Here goes.. .

I'm wondering if the scrubbing agent (i.e. activated carbon) needs to be different for each different application. Meaning if I'm doing hcl/peroxide and then hcl/bleach AND incineration IC chips AND melting the gold once I'm done with all processes. If I need a different type of scrubber for each application, or if I have a homemade scrubber with different levels in said scrubber like one section with carbon, one with urea, one with baking soda etc. What is the most efficient option for scrubbing all fumes. Or is there one? I know a fume hood is a requirement, I am just wondering if since I do incinerate the IC chips and ill be melting the gold once all other steps are completed if I need to have a separate scrubber for each application, or if I can build a multilevel scrubber that will take care of all fumes.

Thanks for any responses your input and info is truly valued.

 

[butcher]

Not having time to write a book, I will try to answer some of your questions.

first, a bit of the chemistry of what your planning on doing.

Scrubbing acid fumes are absorbing them (to remake acids) and/or can involve making the fumes into salts of those acids.

If using water the acidic fumes make the water acidic (one way we can make new acids of the fumes we are scrubbing up to the azeotrope of the acid involved, that is providing we can get good contact and conversion of the fumes, which is dependent on the design and effectiveness of the scrubber itself, we can also use a suitable base solution to make the salt of the acidic fumes or acidic waters, using a base or basic solutions like sodium or potassium hydroxides will make solutions such as KNO3, NaNO3, NaCl, Na2SO4...

Other bases can be used such as carbonates, lime waters... these are not as basic as the hydroxides but also have their place ( especially when working with treating waste)... some types of salts are more easily used in other processes or to remake acids, some salts are less soluble than others, some dry easier or do not absorb or suck up water from their environment as easily so we have these also to consider in our plans or our design.

Scrubbing fumes from a furnace or a burner is a whole different animal, you will not be able to effectively do this without afterburners, baghouses, conical separators, electrostatic precipitators...

A fume hood with a furnace filter and a long duct to condensate values in the cooler portions may be the best you can do to lower the toxicity of these fumes and then pass them through a mist of water (or caustic spray mist to capture as much of the acidic based fumes as possible...

 

[Golddigger1214]

Ok so that was a lot of info. I just want to make sure I'm understanding correctly. Basically I can't do both incineration and my leaching and precipitation all in the same area, unless I have a fume hood that has dual filters for both applications. Am I understanding correctly? If that is the case, I have a home built furnace my husband made out of an old metal barrel. Its quite effective for wood burning and what not it has a smoke stack on top, can I simply add on to that smoke stack or chimney the things needed to capture and filter the fumes from incinerating the IC chips?

Second, if I build a homemade scrubber you're essentially saying that I need to wet scrub the fumes as they're drawn into the fume hood and into the scrubbing system by essentially creating a large enough or long enough area for them to pass through and be drenched with water that has a neutralizing agent in it.

So if I took say a misting system with 4" pvc piping and inside that pvc piping put something like the little plastic goldf balls with holes in them and then all down the pipe placed misters which drew from a tank that held the neutralizing water, that essentially the fumes will me fully neutralized. Correct?

 

[Golddigger1214]

What about pool noodles? Would that be a good surface area to trap the fumes and drench them inside of pvc or some other form of tubing?

 

[butcher]

Fume scrubbers for acids can be made in several different ways.
In a closed heated reactor (distillation apparatus) these can be easily be made or purchased, you can heat the solution and bubble the gases that evolve through the water to make acid in a first stage from the fumes which are more water-soluble (in some cases like with nitric you may wish to add hydrogen peroxide (which will help the non-water-soluble portion of the NOx gas NO to be converted to the more water-soluble NO2 gas...).
Then in a second stage or third stage, the gases that pass the first stage you could have a base or hydroxide solution to convert the gasses that pass other stages to salts of those acids in the final stages.

Other types of scrubbers can be piped off of the fume hood exhaust large towers with fine mist spray nozzles and chemical resistant pumps and may include materials baffles ... to get better contact between the solution and the fumes these are more difficult to build and maintain. and may not be needed if the distillation type scrubber is used...

Spending your time studying the topic will explain much more than I can in a few words.

It really depends on your goal there are different options, and well worth exploring them before deciding what to build or spend your gold on...

 

[Palladium]

It helps to keep all your inquires in one thread sir.

https://www.ebay.com/sch/i.html?_nkw=bio+balls&_sop=12

 

[Golddigger1214]

Palladium im not a sir. And my inquiries were on different topics. My apologies.

 

[Palladium]

Excuse me maam. You have questions spread over 2 separant threads about a fume scrubber and designs when they could just as easily be in one thread where it easier to follow and we can answer your questions accordingly. I understand why you did this looking at the old thread, but what happens is someone will answer a question in one thread and start a discussion and then a discussion will start in another thread and pretty soon it gets confusing. It's easier to keep the discussion in one thread and just post a link or make reference to the other thread.

Can someone post a picture of what the inside of their scrubber looks like, or draw a diagram of how I should place small diameter cut up pvc piping or whatever else people use that is effective. If I do a Google search I will be there for hours. Lol thanks!

What about pool noodles? Would that be a good surface area to trap the fumes and drench them inside of pvc or some other form of tubing?

Both questions are basically the same on two separant threads.

 

[kurtak]

First - there are two types of scrubbers --- (1) closed reaction scrubber - this scrubber works by drawing the fumes from the reaction vessel through the scrubber using a vacuum pump

Here is a thread (about building a fume hood) that also discusses this type of scrubber

:arrow: Building a chemical fume hood with a plain steel blower

(2) open air scrubber - this scrubber works by drawing the fumes from your fume hood by the fan/blower that operates your fume hood

In both of these scrubbers you NEED retention time in the scrubber for the scrubbing solution (hydroxide or carbonate) to react with the acid to neutralize the acid &/or a "large" surface area for the acid to make contact with the scrubbing solution

So you "need" to slow the fumes down &/or disperse then out over a large surface area for the scrubber to work properly

You posted ---------

So if I took say a misting system with 4" pvc piping and inside that pvc piping put something like the little plastic goldf balls with holes in them and then all down the pipe placed misters which drew from a tank that held the neutralizing water, that essentially the fumes will me fully neutralized. Correct?

that is an open air scrubber & - no - that will not work - or at least it will not work well

Why ? --- because the the air/fumes will move through the 4 inch pipe so fast that they wont have the retention time to properly scrub the fumes - you would need a VERY long 4 inch pipe for this to work --- so you "need" to "slow" the air speed down as the fumes pass through the scrubber "portion" of your venting system - so the scrubber portion of your venting system needs to be larger in diameter then the input/output ends of your venting system for the air speed to slow down in the scrubbing column

in other words - if you have a 4 inch pipe going from your hood to your scrubbing column - the scrubbing column would need to be "at least" 12 inches in diameter & 8 to 10 foot long to slow the air speed down & get the needed retention time to properly scrub the fumes - that's just an example - off the top of my head without doing an actual air speed/flow calculation --- actual size of your scrubber column will depend on the air speed &/or volume of the fan/blower that operates your fume hood

In the "closed reaction" scrubber you want to put something like marbles in the scrubber columns to break up the bubbles going through the scrubber solution as well as giving you a large surface area for the scrubbing to work on

And for what it is worth - I would not even consider building a fume hood with anything less then 6 inch piping/ducting coming out of the hood to the scrubber

Kurt

 

[Golddigger1214]

Kurt,

Thank you very much for that info. I was actually going through my idea and had realized that the 4" wouldn't be large enough for this application. I realized that it would need to be extremely long in order to do whats needed. But your explanation was exactly what I needed to see in order to continue my thought process because for me the part that was missing was that it needs time so basically needs to slow down in order to properly decontaminate the fumes.

 

[Golddigger1214]

Palladium

Point taken and my sincerest apologies. I belive i got a bit confused myself with the amount of material on this site, and did not realize I had done as you're pointing out. How do I fix that? I don't want to junk up the system or confuse people.

Also, I'm a bit too young to be a ma'am just yet. Lol its ok tho,its definitely better than mr.

 

[Palladium]

Not a problem maam. Trust me there's plenty of junk around here so it's alright.
Here in the South if you're a lady, then you're a maam, regardless of age!

 

[Golddigger1214]

Thank you. And yes, I'm well aware of how the South is. I've got family in Arkansas, Nebraska, Florida and friends in Texas. My roots and cooking are purely southern. Lol I appreciate your assistance. Hopefully my future posts are with a little less questions, and a bit more success.

 

[Palladium]

Thank you. And yes, I'm well aware of how the South is. I've got family in Arkansas, Nebraska, Florida and friends in Texas. My roots and cooking are purely southern. Lol I appreciate your assistance. Hopefully my future posts are with a little less questions, and a bit more success.

Ask all the questions you want maam. It's how we all learn! We just ask that you research first, because believe it or not while searching for the answers you will actually learn more.

 

[Golddigger1214]

I'll do that. Thank very much.