ReapHer_6
Well-known member
Hi All. I have been lurking more lately as I have not been able to process scrap because I don't believe it is safe enough in my lab because of the fume management system.
I would like to see if I can get some help on building a small benchtop scrubber so I can get back to processing instead of just firing experiments and money at the problem. I have used the search function and I have done my homework. I am ready to begin trying to solve the problem on my own which I find really enjoyable but by the time I reinvent the wheel I will have spent more than the cost of an actuall scrubber and it will be weeks before I can actually just process scrap.
First, my setup. I know it might not be the best setup but it works really well.
I will try to attach a pic, but this is what I have done.
I use a jacketed 500ml 3 neck flask (24/40) as my reactor. I have a 250ml pressure equalizing additional funnel in the center neck. I have a 400mm Allihn condenser then I vent the top of the condenser to atmosphere. I use a exhaust fan to pressurize a 4" smooth wall plastic pipe that is 40' long. I use the suction side of the exhaust fan to draw negative pressure through the reactor. I then use a fish tank air pump to add air into the chamber aiding the circulation of the gasses up to the condenser. I tested the setup and the pipe from the fan will suck out a bic lighter flame. So I got it right. I just add air in the reactor as it seems to stagnate in the chamber somewhat.
Now, I use hot water in a glass 2 gallon tank on the left of the reactor and a pump circulates the heated water around the reactor. I can precisely control the temps allowing me to warm up the reactor and the acids. I then keep the temps as close to but not over 135 degrees.
I have a 2 gallon glass tank on the right of the reactor that I put a bag of ice into the water and circulate it to chill the condenser. (I add blue food coloring so I can see the movement in the condenser). I chill the condenser to less than 40 degrees and then I begin the process. I have an additional funnel on the right neck of the reactor that is filled with DH20 to act as an emergency reaction shutdown.
I use the calculation of 150ml of reactor space per 1oz of material. I process no more than 1.5oz at a time.
The reason for the additional funnel and the condenser is to recover nitric. as I understand it, what condenses back down is pure nirtic.? I use the method of adding nitric then HCL, then nitric, then hcl until the process is over and I avoid overdosing the nitric.
Laslty I have used the NOx reduction with the ethelglychol / 35% peroxide process. It does work but only by putting it into use with a bulk AR process. The process of adding nitric then hcl back and fourth makes the math downright unbearable if not just about impossible.
Ok so here is the issue I need help with. Some of you might have seen the posts on my building layout and the limitations I am under but I will briefly recap them. I am in a section of the building that has car and foot traffic directly outside. The only outlet I have access to without altering the building is a 4" vent that is 45' away from my lab table. This is not the entire length of exhaust path, just the straight section in the ceiling. I tried to build a venturi and it worked really well until I hooked up the 40' length of pipe. I asked the forum about this (and a friend that is an engineer) and everyone agrees, I need to put a blower at the end of the run and suck the fume hood through it. The problem is I don’t have a fan or the funds to get an acid rated fan. And the outlet just so happens to be above the lawyers conference room. I have access to the outlet but I can't put a large or noisy fan there. So I turned my thinking to a scrubber. I have tons of ideas and I have read hundreds of posts here about them. But I wanted to ask for help with specifics.
I don't see an answer to the fume hood in the near future so to get me back to the fun, I want to get a scrubber up and running as soon as I can to treat the fumes from the reactor. I have 3/8 fitting on the top of the condenser, so that is my ID of my outlet to the scrubber. I have access to some money (just not a great deal), and just about every tool known to man in my shop at our disposal.
I don’t know what to do to get the fumes through the scrubber. Positive pressure is easiest for me to do. But it is not the right way.
So I need to solve the air movement issue. Use a blower, a vacuum fan, a compressor as a vacuum source?? (I have a new wine cooler that I removed the compressor from so I could use the actual cooler itself as a small fume hood. I have heard that these can make good acid fume suction devices....) Regardless of the device, I don't know how to size it. I don't know type to get or where to get it. I would like to try to not spend a ton on it. As far as the scrubber, sizing it depends on the volume of air to process which is determined by the air movement source. The condenser does a good job of recouping acid but the final amount of NOx vs. air is unknown. So I don't know what to do next.
I would like to do it right and on a budget. I understand wet scrubber principles and construction, and I have a supplier of water misters and bio balls and pumps etc. I can get a continuous PH digital meter and then add alkali as needed so I think I could build one that would keep the final air going through the vacuum good enough to keep it healthy.
I would love any help I can get so I can stop dreaming of processing stuff and actually get back to doing it. I am going crazy (ier)
John S.
I would like to see if I can get some help on building a small benchtop scrubber so I can get back to processing instead of just firing experiments and money at the problem. I have used the search function and I have done my homework. I am ready to begin trying to solve the problem on my own which I find really enjoyable but by the time I reinvent the wheel I will have spent more than the cost of an actuall scrubber and it will be weeks before I can actually just process scrap.
First, my setup. I know it might not be the best setup but it works really well.
I will try to attach a pic, but this is what I have done.
I use a jacketed 500ml 3 neck flask (24/40) as my reactor. I have a 250ml pressure equalizing additional funnel in the center neck. I have a 400mm Allihn condenser then I vent the top of the condenser to atmosphere. I use a exhaust fan to pressurize a 4" smooth wall plastic pipe that is 40' long. I use the suction side of the exhaust fan to draw negative pressure through the reactor. I then use a fish tank air pump to add air into the chamber aiding the circulation of the gasses up to the condenser. I tested the setup and the pipe from the fan will suck out a bic lighter flame. So I got it right. I just add air in the reactor as it seems to stagnate in the chamber somewhat.
Now, I use hot water in a glass 2 gallon tank on the left of the reactor and a pump circulates the heated water around the reactor. I can precisely control the temps allowing me to warm up the reactor and the acids. I then keep the temps as close to but not over 135 degrees.
I have a 2 gallon glass tank on the right of the reactor that I put a bag of ice into the water and circulate it to chill the condenser. (I add blue food coloring so I can see the movement in the condenser). I chill the condenser to less than 40 degrees and then I begin the process. I have an additional funnel on the right neck of the reactor that is filled with DH20 to act as an emergency reaction shutdown.
I use the calculation of 150ml of reactor space per 1oz of material. I process no more than 1.5oz at a time.
The reason for the additional funnel and the condenser is to recover nitric. as I understand it, what condenses back down is pure nirtic.? I use the method of adding nitric then HCL, then nitric, then hcl until the process is over and I avoid overdosing the nitric.
Laslty I have used the NOx reduction with the ethelglychol / 35% peroxide process. It does work but only by putting it into use with a bulk AR process. The process of adding nitric then hcl back and fourth makes the math downright unbearable if not just about impossible.
Ok so here is the issue I need help with. Some of you might have seen the posts on my building layout and the limitations I am under but I will briefly recap them. I am in a section of the building that has car and foot traffic directly outside. The only outlet I have access to without altering the building is a 4" vent that is 45' away from my lab table. This is not the entire length of exhaust path, just the straight section in the ceiling. I tried to build a venturi and it worked really well until I hooked up the 40' length of pipe. I asked the forum about this (and a friend that is an engineer) and everyone agrees, I need to put a blower at the end of the run and suck the fume hood through it. The problem is I don’t have a fan or the funds to get an acid rated fan. And the outlet just so happens to be above the lawyers conference room. I have access to the outlet but I can't put a large or noisy fan there. So I turned my thinking to a scrubber. I have tons of ideas and I have read hundreds of posts here about them. But I wanted to ask for help with specifics.
I don't see an answer to the fume hood in the near future so to get me back to the fun, I want to get a scrubber up and running as soon as I can to treat the fumes from the reactor. I have 3/8 fitting on the top of the condenser, so that is my ID of my outlet to the scrubber. I have access to some money (just not a great deal), and just about every tool known to man in my shop at our disposal.
I don’t know what to do to get the fumes through the scrubber. Positive pressure is easiest for me to do. But it is not the right way.
So I need to solve the air movement issue. Use a blower, a vacuum fan, a compressor as a vacuum source?? (I have a new wine cooler that I removed the compressor from so I could use the actual cooler itself as a small fume hood. I have heard that these can make good acid fume suction devices....) Regardless of the device, I don't know how to size it. I don't know type to get or where to get it. I would like to try to not spend a ton on it. As far as the scrubber, sizing it depends on the volume of air to process which is determined by the air movement source. The condenser does a good job of recouping acid but the final amount of NOx vs. air is unknown. So I don't know what to do next.
I would like to do it right and on a budget. I understand wet scrubber principles and construction, and I have a supplier of water misters and bio balls and pumps etc. I can get a continuous PH digital meter and then add alkali as needed so I think I could build one that would keep the final air going through the vacuum good enough to keep it healthy.
I would love any help I can get so I can stop dreaming of processing stuff and actually get back to doing it. I am going crazy (ier)
John S.
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