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Author: Subject: Acid neutralizing on industrial scale
Deathunter88
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[*] posted on 22-4-2022 at 10:19


Quote: Originally posted by Tsjerk  
Quote: Originally posted by unionised  


Incidentally, the heat evolved is well documented.
https://en.wikipedia.org/wiki/Enthalpy_of_neutralization


[Edited on 16-4-22 by unionised]


I was just doing some calculations on the back of an old envelope and the solution won't get close to boiling, even if you would dump in solid NaOH. Unless you start at ridiculously high temperatures of course.


Remember that's assuming perfect homgeneity and perfect mixing, which is very different from reality. If you want to prove this to yourself, fill a large graduated cylinder with water and dump in a couple hundred grams of NaOH. What you'll get is a geyser of boiling hot caustic solution spewing out. And that's just from the heat of solvation.

[Edited on 22-4-2022 by Deathunter88]
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Rainwater
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[*] posted on 22-4-2022 at 15:07


I have really enjoyed the challenge this problem has presented. I've read almost 20 papers and patent on the subject as well as provided a pretext for contacting some old friends I haven't spoken to for too long. The methods for dealing with this type of waste are well documented.

Quote: Originally posted by SWIM  
Well yeah, but if the OP is trying to avoid buying (or doesn't have room for)a neutralization tank it sounds like these more elaborate setups are off the table.

Looks like simple is a big priority here.



The 6 P's should be applied here.

Methods of disposing waste products should be well studied before any reaction is run. This constitutes proper and ethical chemistry. The methods to neturalize the waste product in question are presented in many posts of this thread.

From the impression I got, this reaction will be run again. Neturalizeing and shipping the waste is the most expensive solution I have seen.

For the first 9kL, this may be acceptable, but after this waste is disposed of, their will be more generated. Thus increasing cost. And there is no guarantee that the disposal company will do the work properly.

The original question was answered in the first few replies. But the problem, at least it is my opinion, was not solved.
The question I chose to answer is "How can this waste be dealt with in a manner that will improve process profitability with minimal cost, labor and environmental impact?".

Thus, the initial setup will be more expensive than paying someone else to dispose of the material. Because their is no need for additional reagents or labor, in my opinion, for a continuous process, continuous waste treatment is advisable.

Edit:
Quote: Originally posted by Bonee  
Could try multi stage reverse osmosis or electrodialysis as well. Although the ethylene glycol may complicate things.
see patent.
https://patents.google.com/patent/US7976710B2/en

If you could get this to work. That would be your best option

Edit:
Detailed instructions and analysis of pva membranes amd their properties.
www.mdpi.com/2073-8994/12/6/960/htm
Attachment: Pva membrane study.pdf (7.4MB)
This file has been downloaded 47 times

Easy to follow video tutorial on making a membrane
http://www.sciencemadness.org/talk/viewthread.php?tid=158099


[Edited on 23-4-2022 by Rainwater]




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Sulaiman
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[*] posted on 23-4-2022 at 13:05
OR


Maybe better for future runs to scrub the ethylene oxide by condensing (and collecting) it?

Edit : buying/leaasing/renting and running costs of refrigeration/heat exchanger plant may be overall economical?
producing products instead of waste,
... I have no idea of costs involved, markets, regulations etc.

[Edited on 24-4-2022 by Sulaiman]




CAUTION : Hobby Chemist, not Professional or even Amateur
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[*] posted on 23-4-2022 at 22:08


Rainwater,

I don't think using home-made membranes is on the table either.

However I am impressed that you can come up with cost-benefit analyses from the information presented.

You got a nice big crystal ball back home to help out with that?

The impression you got is that this reaction will be run again.
If you read and understood the posts you shouldn't have to rely on any impressions.

You're also getting pretty didactic for a "not an expert"
I've found this to be a common reaction from posters when they realize they're in over their head and soiling their union suits. :P





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Tsjerk
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[*] posted on 24-4-2022 at 01:45


Quote: Originally posted by Deathunter88  


Remember that's assuming perfect homgeneity and perfect mixing, which is very different from reality. If you want to prove this to yourself, fill a large graduated cylinder with water and dump in a couple hundred grams of NaOH. What you'll get is a geyser of boiling hot caustic solution spewing out. And that's just from the heat of solvation.

[Edited on 22-4-2022 by Deathunter88]


Yes, although I wasn't really suggesting to use solid NaOH, here you would only need relatively little NaOH, as the sulfuric acid is only 5% (w/w?). With 2 molar eq. NaOH dissolved that would only raise the temperature by about 15 degrees, not taking any water in account that was used to dissolve the NaOH. Without dissolving it first you would raise the temperature by about 30 degrees.

But 10% NaOH mixed in with a mixing valve, with a continuous pH probe down the line sounds reasonable to me. That way the mixing is practically homogeneous and you would have a realtime view on how the mixing is going.
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[*] posted on 24-4-2022 at 05:34


The more research I read, the more I think distillation is the completely wrong approach,
Here is a paper explaining the use of co2 to produce ethylene glycol,

But, as for a running process, it seems to be much more efficient than anything else I've suggested, as well as working at temperatures less than 80c.
It appairs the running cost would consist of maintaining the operating temp, and the production of co2 for the reaction.

Tho the OP request a method to neturalize the scrubbing solution for proper disposal, this method, if it works, will achieve the same end effect, with minimal alterations to the existing apparatus

Attachment: EP0776890A2.pdf (261kB)
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Tsjerk
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[*] posted on 24-4-2022 at 13:06


@Rainwater: that process would require a new gas feed, CO2, and a catalyst. That would be a complete new process which would have to be set up, optimized and what not. While OP states that he doesn't even have access to a neutralization container; a mixing valve is what could be done.
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[*] posted on 24-4-2022 at 14:22


Just throwing out ideas that will not cause the problem of acidity
Loving the research im finding.
Mr Gears. What is the rate of EO entering the scrubber?
Is it a closed loop system or open to the atmosphere?




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[*] posted on 25-4-2022 at 04:04


Quote: Originally posted by WGTR  

Anyway, is the tank pumped out, or is it emptied via gravity flow?

The scrubber consist of 14 cells. Each cell have to be pump. Which also means that it would not be a continuous flow of all 9000 L through a inline neutralizer.

Quote: Originally posted by Rainwater  

Mr Gears. What is the rate of EO entering the scrubber?
Is it a closed loop system or open to the atmosphere?


5,58 kg of EO is added to a 12 m3 vacuum chamber, which is at that time at 120 mbar and of relative humidity of 60%. It's topped of with nitrogen to 930 mbar. That's somewhere about 400mg/L EO.
After dwell time, the 12 m3 mix of EO, N2 and water vapor is emptied over an a period of 60 min.


Alternatively the the whole waste disposal could be eliminated by burning off the EO, but the Sterigenics incident put an end to that discussion, despite the fact that it was human error.
https://www.youtube.com/watch?v=_2UnKLm2Eag
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[*] posted on 25-4-2022 at 08:10


Quote: Originally posted by Broken Gears  

Alternatively the the whole waste disposal could be eliminated by burning off the EO, but the Sterigenics incident put an end to that discussion, despite the fact that it was human error.
https://www.youtube.com/watch?v=_2UnKLm2Eag


Well... That surely was not just an human error, because it shouldn't be possible to blow up a building with a single password.
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[*] posted on 25-4-2022 at 21:03


Thinking out loud again.

When neturalizeing the solution within the reactor, percipitates can be a problem.
Solubility tables will be less accurate due to the 30% EG solution.

The temperature of the neturalizeing is another issue.
The byproducts and side reactions will be another issue.

Inline mixing valves and manifolds only work with fluidsliquids/gases, increasing the total volume/pressure. So, head space within the apparatus would be required.

Solid neturalizeing agents would create a long list of problems, stearing away from those for now.

This is a gas scrubber. So, adding gas would be rather simple. But, pressure and time become an issue.
Time for the reaction to proceed and the extra pressure from the gas to drop as it is absorbed and reacted.

Ammonia comes to mind as it acts as a base when it encounters water, but ammonia sulfate is insoluble in alcohol. So, with a 30% mass of glycol, percipitate may cause an issue requiring a rinse cycle of the reactor.

I'm not sure what other gases are alkaline or if ammonia would be a compatible choice because of reactions with other products in the mix.
A complete list of all known compounds in the scrubbing solution would aid in perducting side reactions




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[*] posted on 25-4-2022 at 23:20


Quote: Originally posted by Tsjerk  
Quote: Originally posted by Broken Gears  

Alternatively the the whole waste disposal could be eliminated by burning off the EO, but the Sterigenics incident put an end to that discussion, despite the fact that it was human error.
https://www.youtube.com/watch?v=_2UnKLm2Eag


Well... That surely was not just an human error, because it shouldn't be possible to blow up a building with a single password.

The error was made by the human who designed the system.
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