RogueRose
International Hazard
Posts: 1590
Registered: 16-6-2014
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Scrubbing CO2 & absoprtion into LiOH or Ca(OH)2
I was looking at rebreathing units that scrub CO2 from the air you breath and then recirculate the air by injecting a little more O2 into the gas and
I noticed that LiOH is often cited as the material used for this process but did notice that some sites are citing the use of Ca(OH)2 as "dive lime".
I was wondering if anyone has any experience with these units or with scrubbing CO2 with either substance and was wondering if this is usually done in
a dry form, the hydroxide as a powder or if the air needs to be dried before being scrubbed. It seems the calcium would also produce a molecule of
water with each CO2 absorbed but I doubt this would effect the performance very much though IDK.
My other question is if they would perform at the same relative speed and if there are any factors that effect the speed at which CO2 is absorbed into
the media.
When I studied CO2 sequestration from coal power plants it seemed that they bubbled the exhaust gases through a slurry of Ca(OH)2 or basically a layer
of Ca(OH)2 totally submerged in water.
If there is not much difference in performance the main benefits of the lithium is it weighs 63% of the calcium once the carbonate/water is formed and
the cost is many orders of magnitude higher for the lithium.
I don't know if these CO2 filters are reused (recharged/regenerated) but it seems that the Calcium would be easier to regenerate but I suspect this
would be difficult to do in any small scale for personal devices. If anyone knows how they reuse these systems and how they do it, please let me know.
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Bedlasky
International Hazard
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Registered: 15-4-2019
Location: Period 5, group 6
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If you want just scrub CO2, Ca(OH)2 should be fine. But if you want also generate oxygen, you need Li2O2 (not LiOH).
2Li2O2 + 2CO2 --> 2Li2CO3 + O2
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