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Don't exactly know how AI can generate a design but it seems to have settled on two things, both in error. One is that you will experience any longevity with a carbon filtration unit working on pass through air, and Two, you are scrubbing 100% of the air exhausting from the hood.
Exactly what design parameters did you give it?
Exactly what design parameters did you give it?
skinny
Well-known member
and this is why i wanted to discuss it. first off what is the error with scrubbing 100 percent of the air from the fumehood? to me this sounds like a positive thing not a negative when dealing with these gasses. second what do you mean about the carbon filters? im not really going for longevity im going for safety in my space but also the only carbon filter in that diagram is in the air scrubber itself and those filters are replaceable. and i argued with a.i. for about 4 hours on different designs before settling on this one. firstly with perameters i specified only refining 10 ozs of gold a week or less i also stated that i want the least corrosion of my equipment and i want to safely expel the air 15 ft above the ground. i asked it to run some models using my design and about a hundred other questions.
skinny
Well-known member
brother ghat gpt 4 can do some things most of them wrong but i can feed it diagrams equipment lists and goals and itll design something to meet them most wernt successful but i through this one in with a few variations and it said this here is gonna be the most efficient. all labware eventually goes out im not trying to ignore that i just want to be able to experiment and learn safely i know im not a pro or a chemist
The most economical scrubbing is wet scrubbing which will neutralize the fumes, carbon will entrap some of the fume but it needs replacement and that can be costly. If carbon were the method of choice I would expect to see it used more often yet no refiners use it commercially.
The reason you do not scrub everything is size. For effective fume removal, the rule of thumb is 100 CFM for every square foot of hood opening. If your hood opening is 4 feet wide and 3 feet tall that translates into a blower removing 1200 CFM of air. For NOx scrubbing to be effective the fume needs to be retained in the scrubbing section (where the wet chemistry happens) for 8 seconds. To contain 1200 cubic feet of scrubbed air the scrubber needs to be quite large with the packed area alone being 160 cubic feet. For this reason the air exhausted from your hood needs to be the 1200 CFM suggested but that is called fugitive emission and it is un-scrubbed. The scrubbed air can get by with substantially less by using scrubbed drops to pick up the concentrated fumes from each reaction.
I recently worked with a company that set up a modestly sized operation for aqua regia refining and their 3, 8' hoods were serviced by a scrubber with a 625 CFM fume scrubber. To give you an idea of the size that is, I posted a thread about the setup here
The reason you do not scrub everything is size. For effective fume removal, the rule of thumb is 100 CFM for every square foot of hood opening. If your hood opening is 4 feet wide and 3 feet tall that translates into a blower removing 1200 CFM of air. For NOx scrubbing to be effective the fume needs to be retained in the scrubbing section (where the wet chemistry happens) for 8 seconds. To contain 1200 cubic feet of scrubbed air the scrubber needs to be quite large with the packed area alone being 160 cubic feet. For this reason the air exhausted from your hood needs to be the 1200 CFM suggested but that is called fugitive emission and it is un-scrubbed. The scrubbed air can get by with substantially less by using scrubbed drops to pick up the concentrated fumes from each reaction.
I recently worked with a company that set up a modestly sized operation for aqua regia refining and their 3, 8' hoods were serviced by a scrubber with a 625 CFM fume scrubber. To give you an idea of the size that is, I posted a thread about the setup here
I seem to remember a quote (from the internet?) by Abraham Lincoln where he said you can't believe everything you read on the internet!
skinny
Well-known member
thanks for the responses brothers,
i want to stress that i am not a commercial operation i will not be doing commercial amounts and my operation will not be in use 24/7 i dont know if that makes a difference to your understandiung of my goals. and i am well aware of a.i. being a text prediction more than intelligence but what it does do is search through amazin amounts of data for you and brings you the highlights and just like humans sometimes its wrong i have a respect for that and thats why im comparing these notes here. now i hear you on the cfms and all that. so lets assume i change the size from 4x3x3 to 3hx2dx3w and recalculate? the air scrubber im looking at is an alorair hepa550 3 stage with charcoal filters are relatively inexpensive my booster fan will be placed closer to exterior but before a final merv filter with activated carbon sheets.
lets assume im borderline retarded, i do not understand the calculations and chemical reactive nature of wet scrubbers how and when to implement one or where to look to get one for my scale. again i need to express im doing .5m solutions maybe only refining a couple ozs of gold at a time and less than 30 ozs of silver at a time. ive seen some pictures and i understand kind of what they do to make the fumes safe but getting the fumes from the beaker through the scrubber and vented outside i dont know. with this air scrubber design theres minimal obstruction slowing airflow down and also i dont need to completely clean the air i just need it clean enough to expell overhead again i dont know if that really makes a difference.
A HEPA filter will not absorb NOx ask AI it will tell you. Activated carbon will absorb and trap NOx but it will overload.
Then there is the nasty little fact that HEPA filter units with carbon absorption packs are made of metal. Refining fumes eat metal for a living. That's why fume scrubbers are PVC or fiberglass resin.
You can make a very small fume scrubber that will handle your fumes from the reaction sizes you mention. Go to this thread and click on the searches mentioned about fabricating hoods and scrubbers. HERE
Then there is the nasty little fact that HEPA filter units with carbon absorption packs are made of metal. Refining fumes eat metal for a living. That's why fume scrubbers are PVC or fiberglass resin.
You can make a very small fume scrubber that will handle your fumes from the reaction sizes you mention. Go to this thread and click on the searches mentioned about fabricating hoods and scrubbers. HERE
skinny
Well-known member
man i looked through that thread but its overwhelming i dont know how to construct a wet scrubber like that. the beaker set up i can understand your pulling fumes through the solutions to clean it but i am overwhelmed. all the home refiners ive ever watched dont seem to have that apparatus and just duct it straight out there roof and deal with replacement costs but that method sounds very taboo here id like to find a comfy medium.. now the air scrubber i mentioned is a plastic unit not metal i dont know about the filters but i mentioned those are also fairly cheap too. now im not gonna be sucking the fumes right of the stack they will be dissipated 15 feet of the ground so im not looking for absolute purity just good enough not to harm a nest of birds on my chimney. is there a setup i can build that youd recommend that is both economical and safe for the amounts ive mentioned? and would you have a diagram or image for me to better understand how to implement it in my garage?
I built this small scrubber from 4 liter vacuum flasks and used it successfully to refine 50 ounce karat gold lots in my lab. This, or something similar will handle the lots you mention.
skinny
Well-known member
can you post the specs on it? i assume its inside the fume hood and with an exhausting fan as a redundancy for fugitive emissions? i also assume you would put a seeing glass over your beaker and the straw in the spout opening and that there is a vacuum pump on the other side out of this picture frame? when i say specs what is the liquid in the flasks and how do i mix the solutions and i see a medium in them what is that and is there a specific amount of it i need? how often does it need to be refreshed?
if i do this and then eliminate the air scrubber and filter box i can essentially vent straight out, but when considering boil overs spills broken glass bad reactions that might be a bad way to do it. but building that is another 500 bucks on top of the grand id need to build my fume hood with an air scrubber and filter box so besides that scrubber what do you use on that rig to vent the fume hood and expell?
edit: i have been on this forum every waking minute since i found it and i just want to say thank you for addressing my questions here while i also look for them everywhere else. i just want you know i appreciate that even though its an annoyance and probably makes look pretty stupid. but i am here in the pursuit of knowledge and passion my kids deserve to see what that looks like AND afforded the opportunity to do it them selves. much love and respect
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skinny
Well-known member
i found these on amazon i think will work do i need 3 and can i add on after that? do you think this would suffice? than ill need the medium and solutions that go in them
Attachments
The scrubber in the photo above was all off the shelf glassware and CPVC copper pipe size pipe. The material in the flasks is bioballs used in aquarium filters for bacteria to grow on (large surface area to aeration ratio) The vacuum is supplied by a venturi fitting with tap water flowing through it to draw a vacuum and pull the fumes through the setup. Glassware has gotten expensive and some members made similar setups using PVC pipe and fittings, they were mentioned in the threads I linked above.
This was located outside of the hood as the fumes are contained while passing through it and no sense taking up valuable hood space. I wrote a thread about building it but for the life of me I cannot find it.
This was located outside of the hood as the fumes are contained while passing through it and no sense taking up valuable hood space. I wrote a thread about building it but for the life of me I cannot find it.
This is an example of ones that I used. They attached to the outside my building and lines routed the fumes through them. Aided by the use of a vacuum pump made for servicing automotive AC unit at the time.
A few things I would change making one today:
1: use flat ended caps to make them easier to stand up on a flat surface.
2: Larger pipe fitting for the vacuum lines to attach to .
skinny
Well-known member
i looked through the threaded link but im still a little unsure here, bioballs in the flasks i got that part is it all 3? the solution im seeing your saying is tap water? ive heard of others using hydrogen peroxide in atleast one of them is this wrong? outside the fume check but whats not in the picture or maybe i cant identify is the part that is vacuuming the fumes from the fume to the outside id like to see that as an example if possible i di some searches looking for our thread and i couldnt find it. ill have to locate cpvc piping but if its feasable id rather keep plastic tubing flexable if i can i still dont understand if your fume hood has an exhaust fan setup or not and what that looks like i have a million other questions can i ask just one thing to answer all of them? is there any way you can take a video of your setup in action including the fume hood the venturi the scrubber and where the fumes go after the scrubber? it would make most sense to vent them back in to the fume hood and out the exhaust but i want to make sure. i feel like a video would do way more justice here than words or even a diagram which would also be helpful to understanding some of these things
I filled the first one with water and peroxide, the second with water and liquid caustic, and the third with water and liquid caustic. There was no fume visibly carrying over after the 3 flasks. My vacuum was a stronger venturi which I also used for filtration. I generated the vacuum by pumping closed loop water theough the venturi fitting. The drum eventually picked up the small of metabisulfite so it vented into my fugitive emission duct which essentially vented the scrubbed fume as well.
My exhaust hood, and all of the hoods I have had clients set up, always have strong exhaust of fugitive emissions and when the EPA required it, fume scrubbed emissions.
I have retired and do not have any more access to these setups so a video is out of the question.
My exhaust hood, and all of the hoods I have had clients set up, always have strong exhaust of fugitive emissions and when the EPA required it, fume scrubbed emissions.
I have retired and do not have any more access to these setups so a video is out of the question.
I will post a couple of older videos, just to show how simple they can be. They aren’t the best way, but economically serviceable. These aren’t my videos but are from an older member under a different name on the forum. While I can’t recall his user name here, I did learn much from his posts and videos back in the day.
Fume hood redesign
Home made fume hood
Fume hood redesign
Home made fume hood
His username here is goldenchild.
Dave
Dave
That’s it. Thanks.
