A new type of sorb

joshhan2000 · 8th January 2006, 02:25

I have posted here before and got a lot of good feed back. So here is my question. Why has there not been anyone else looking at new tech for absorbing CO2. The current tech date back about 5000 years to a goat bladder and some baked sea shells. It has not changed much since then. I know that maybe the electronics final caught up with the market to allow for reliable controls. When I started looking at this problem I contacted the right people and they gave me some advise. Basically I have seen the improvement in implication of the system but not much different then the goat bladder. There are two things you need to make a rebreather. O2 and sorb. Every thing else just make it work better but if get rid of any of those two it just does not work any more.

Ok guy hold on I going to do some math and I hope I will not loose anyone while doing this

Ideal gas law is PV=nRT
P is pressure
V is volume
n is moles
R is a gas constant
T is temp in Celsius

When a person is breathing for every mole of oxygen use 90% come out as CO2. Ca(OH)2 Has an equilibrium of 55%. Model by the balance equation of

Ca(0H)2 + .55CO2 ----à CaCO3 + H20

So using this info we can come up with the following math

(PVo – PVf ) * .9 * 74
__________________= gram of Ca(OH)2

RT * (.55)

Po is initial pressure of O2
Pf is final pressure of O2
R is gas constant
T is temp in Celsius
V = volume
.9 is the O2 to CO2 conversion
74 is the molecular weight of Ca (OH)2
.55 is the equilibrium point

As you can see there is lots of room for improvement. I have some idea I am going to be trying in the lab over the next 3 mouths. All I can figure is that you really can not see the chemistry so no one gives it a thought. But if you could realize that at best only half of the chemical on your back gets use at a time then you just might think more about it

abowie · 8th January 2006, 03:05

At the risk of engendering a debate that I really don't want to enter into, I would make a couple of points.

Firstly the respiratory exchange ratio is closer to 0.8. If you don't believe me have a look at the mitochondrial reactions in a biochemisry book.

Secondly I seem to recall (and this is really pushing my memory as the exam I learned this for was nearly 15 years ago) "sorb" contains other agents, particularly KOH, which act to promote the interaction of Ca(OH)2 with CO2. Essentially the KOH is much more active, reacts with CO2 to form intermediate compounds which them react with the Ca(OH)2. This both promotes the reactivity of Ca(OH)2 and also reforms the KOH which them goes through the process again. So I'm not entirely sure that the equilibrium constant you're quoting is the only thing that is affecting the wider outcome.

If you can make a more efficient CO2 absorber, the world, and lots and lots of money, will beat a path to your door. Good luck with it.

joshhan2000 · 8th January 2006, 03:21

Yes there are other chemical in the sorb but they are all alkaline earth metals having the same sort of reaction. The binding of O2 is at 90% not because of the mitochondrial exchange rate but also the exchange rate of CO2 to O2 in the hemoglobin and O2 is use in more function of the body then just the mitochondrial respiration. But not getting into that you can just simply change the .9 to whatever number you want to and use the rest of the equation. But to my main point to the thread is that at ideal condition you will get a 55% usage of sorb. Under real use condition you will get even less. I know every one has said good luck and please make some for me. But I am just wondering why no one else is looking into it. And why more people are not more interested in funding the research. I myself have found a lot of research on it and talking to other chemist on the subject I have see outside of the diving field many new way of scrubbing CO2
Here is a list that I am put together by no mean is it complete.

compound
chemical formula
Molecular weight
Capacity gm CO2/gm
Available O2 gm 02/gm
alkali metal hydroxides

Potassium hydroxide
KOH

56.1

0.392

0

Sodium hydroxide
NaOH

40

0.919

0

Lithium Hydroxide
LiOH

23.9

0.919

0

Alkali earth metal hydroxide

Barium hydroxide
Ba(OH)2

171.4

0.257

0

Calcium hydroxide
Ca(OH)2

74.1

0.594

0

Magnesium hydroxide
Mg(OH)2

58.3

0.755

0

Lithium superoxide
LiO2

38.9

0.566

0.617

Sodium superoxide
NaO2

55

0.4

0.436

Potassium peroxide
KO2

71.1

0.309

0.338

Lithium peroxide
Li2O2

45.8

0.96

0.349

Sodium peroxide
Na2O2

78.8

0.564

0.205

MEA aminomethanol
CH7NO

47.05

0.901

0

2-aminoethanol
C2H7NO

61.08

0.85

0

***jradomski*** · 8th January 2006, 03:21

Quote: (Originally Posted by abowie)

At the risk of engendering a debate that I really don't want to enter into, I would make a couple of points.

Firstly the respiratory exchange ratio is closer to 0.8. If you don't believe me have a look at the mitochondrial reactions in a biochemisry book.

Secondly I seem to recall (and this is really pushing my memory as the exam I learned this for was nearly 15 years ago) "sorb" contains other agents, particularly KOH, which act to promote the interaction of Ca(OH)2 with CO2. Essentially the KOH is much more active, reacts with CO2 to form intermediate compounds which them react with the Ca(OH)2. This both promotes the reactivity of Ca(OH)2 and also reforms the KOH which them goes through the process again. So I'm not entirely sure that the equilibrium constant you're quoting is the only thing that is affecting the wider outcome.

If you can make a more efficient CO2 absorber, the world, and lots and lots of money, will beat a path to your door. Good luck with it.

The same goes for NaOH.. its a faster reaction than the Ca(oh)2 doing the reaction directly..
I have the equatoons in another thread.

http://www.rebreatherworld.com/26120-post11.html

abowie · 8th January 2006, 03:58

Quote: (Originally Posted by jradomski)

The same goes for NaOH.. its a faster reaction than the Ca(oh)2 doing the reaction directly..
I have the equatoons in another thread.

http://www.rebreatherworld.com/26120-post11.html

Indeed you are correct Joe.

Like I said, it's been 15 years and my brain just isn't what it used to be

Underwaterbear · 8th January 2006, 16:06

I'm confused as to where you got this .55 factor.

Back when I studied stoichiometry there was no .55 in the chemical equation you presented. The equation will simply not balance with it in there.

Sorry, but if the rest of your argument follows from this mysterious .55, I think you have a problem.

Cheers
AB

Duncan Price · 8th January 2006, 16:07

Quote: (Originally Posted by joshhan2000)

Here is a list that I am put together by no mean is it complete.

The other alkali hydroxides have been used in scrubbers - LiOH most famously in the CisLunar but Na and KOH are of historical interest as used in the Fluess unit.

Super and per-oxides have and are used in Russian units and on board the Mir space station. They have an alarming tendency to catch fire when wet.

Organic amines are used on modern scrubbers in nuclear subs and the international space station. They can be regenerated easier as can silver/zinc hydroxides.

Personally I'd like to use a microwave plasma for the direct cracking of CO2 back to its elements rather than relying on messy chemistry.

E-man · 8th January 2006, 17:14

Don't forget about the price...lime (calcium) is cheap, hence fairly cheap sorb.
Lithium isnt cheap.
Comes to the problem i see with the extendair absorbents, more efficient use of the calcium, but at a higher cost.

8th January 2006, 02:25	#1 (permalink)
joshhan2000 New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Dec 2005 Location: olympia wa usa Posts: 46	A new type of sorb I have posted here before and got a lot of good feed back. So here is my question. Why has there not been anyone else looking at new tech for absorbing CO2. The current tech date back about 5000 years to a goat bladder and some baked sea shells. It has not changed much since then. I know that maybe the electronics final caught up with the market to allow for reliable controls. When I started looking at this problem I contacted the right people and they gave me some advise. Basically I have seen the improvement in implication of the system but not much different then the goat bladder. There are two things you need to make a rebreather. O2 and sorb. Every thing else just make it work better but if get rid of any of those two it just does not work any more. Ok guy hold on I going to do some math and I hope I will not loose anyone while doing this Ideal gas law is PV=nRT P is pressure V is volume n is moles R is a gas constant T is temp in Celsius When a person is breathing for every mole of oxygen use 90% come out as CO2. Ca(OH)2 Has an equilibrium of 55%. Model by the balance equation of Ca(0H)2 + .55CO2 ----à CaCO3 + H20 So using this info we can come up with the following math (PVo – PVf ) * .9 * 74 __________________= gram of Ca(OH)2 RT * (.55) Po is initial pressure of O2 Pf is final pressure of O2 R is gas constant T is temp in Celsius V = volume .9 is the O2 to CO2 conversion 74 is the molecular weight of Ca (OH)2 .55 is the equilibrium point As you can see there is lots of room for improvement. I have some idea I am going to be trying in the lab over the next 3 mouths. All I can figure is that you really can not see the chemistry so no one gives it a thought. But if you could realize that at best only half of the chemical on your back gets use at a time then you just might think more about it
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8th January 2006, 03:05	#2 (permalink)
abowie Fighting Girl Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: May 2005 Location: Land of Oz Posts: 573	Re: A new type of sorb At the risk of engendering a debate that I really don't want to enter into, I would make a couple of points. Firstly the respiratory exchange ratio is closer to 0.8. If you don't believe me have a look at the mitochondrial reactions in a biochemisry book. Secondly I seem to recall (and this is really pushing my memory as the exam I learned this for was nearly 15 years ago) "sorb" contains other agents, particularly KOH, which act to promote the interaction of Ca(OH)2 with CO2. Essentially the KOH is much more active, reacts with CO2 to form intermediate compounds which them react with the Ca(OH)2. This both promotes the reactivity of Ca(OH)2 and also reforms the KOH which them goes through the process again. So I'm not entirely sure that the equilibrium constant you're quoting is the only thing that is affecting the wider outcome. If you can make a more efficient CO2 absorber, the world, and lots and lots of money, will beat a path to your door. Good luck with it. __________________ Andrew Bowie Rebreather-friendly Buddy
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8th January 2006, 03:21	#3 (permalink)
joshhan2000 New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Dec 2005 Location: olympia wa usa Posts: 46	Re: A new type of sorb Yes there are other chemical in the sorb but they are all alkaline earth metals having the same sort of reaction. The binding of O2 is at 90% not because of the mitochondrial exchange rate but also the exchange rate of CO2 to O2 in the hemoglobin and O2 is use in more function of the body then just the mitochondrial respiration. But not getting into that you can just simply change the .9 to whatever number you want to and use the rest of the equation. But to my main point to the thread is that at ideal condition you will get a 55% usage of sorb. Under real use condition you will get even less. I know every one has said good luck and please make some for me. But I am just wondering why no one else is looking into it. And why more people are not more interested in funding the research. I myself have found a lot of research on it and talking to other chemist on the subject I have see outside of the diving field many new way of scrubbing CO2 Here is a list that I am put together by no mean is it complete. compound chemical formula Molecular weight Capacity gm CO2/gm Available O2 gm 02/gm alkali metal hydroxides Potassium hydroxide KOH 56.1 0.392 0 Sodium hydroxide NaOH 40 0.919 0 Lithium Hydroxide LiOH 23.9 0.919 0 Alkali earth metal hydroxide Barium hydroxide Ba(OH)2 171.4 0.257 0 Calcium hydroxide Ca(OH)2 74.1 0.594 0 Magnesium hydroxide Mg(OH)2 58.3 0.755 0 Lithium superoxide LiO2 38.9 0.566 0.617 Sodium superoxide NaO2 55 0.4 0.436 Potassium peroxide KO2 71.1 0.309 0.338 Lithium peroxide Li2O2 45.8 0.96 0.349 Sodium peroxide Na2O2 78.8 0.564 0.205 MEA aminomethanol CH7NO 47.05 0.901 0 2-aminoethanol C2H7NO 61.08 0.85 0
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8th January 2006, 03:21	#4 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,817	Re: A new type of sorb Quote: (Originally Posted by abowie) At the risk of engendering a debate that I really don't want to enter into, I would make a couple of points. Firstly the respiratory exchange ratio is closer to 0.8. If you don't believe me have a look at the mitochondrial reactions in a biochemisry book. Secondly I seem to recall (and this is really pushing my memory as the exam I learned this for was nearly 15 years ago) "sorb" contains other agents, particularly KOH, which act to promote the interaction of Ca(OH)2 with CO2. Essentially the KOH is much more active, reacts with CO2 to form intermediate compounds which them react with the Ca(OH)2. This both promotes the reactivity of Ca(OH)2 and also reforms the KOH which them goes through the process again. So I'm not entirely sure that the equilibrium constant you're quoting is the only thing that is affecting the wider outcome. If you can make a more efficient CO2 absorber, the world, and lots and lots of money, will beat a path to your door. Good luck with it. The same goes for NaOH.. its a faster reaction than the Ca(oh)2 doing the reaction directly.. I have the equatoons in another thread. http://www.rebreatherworld.com/26120-post11.html __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated. Last edited by jradomski : 8th January 2006 at 03:24.
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8th January 2006, 03:58	#5 (permalink)
abowie Fighting Girl Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: May 2005 Location: Land of Oz Posts: 573	Re: A new type of sorb Quote: (Originally Posted by jradomski) The same goes for NaOH.. its a faster reaction than the Ca(oh)2 doing the reaction directly.. I have the equatoons in another thread. http://www.rebreatherworld.com/26120-post11.html Indeed you are correct Joe. Like I said, it's been 15 years and my brain just isn't what it used to be __________________ Andrew Bowie Rebreather-friendly Buddy
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8th January 2006, 16:06	#6 (permalink)
Underwaterbear A Prismer in Megland Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: May 2005 Location: Seattle, WA Posts: 168	Re: A new type of sorb I'm confused as to where you got this .55 factor. Back when I studied stoichiometry there was no .55 in the chemical equation you presented. The equation will simply not balance with it in there. Sorry, but if the rest of your argument follows from this mysterious .55, I think you have a problem. Cheers AB
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8th January 2006, 16:07	#7 (permalink)
Duncan Price Sump Monster Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Feb 2005 Location: Wells, Somerset, UK Posts: 336	Re: A new type of sorb Quote: (Originally Posted by joshhan2000) Here is a list that I am put together by no mean is it complete. The other alkali hydroxides have been used in scrubbers - LiOH most famously in the CisLunar but Na and KOH are of historical interest as used in the Fluess unit. Super and per-oxides have and are used in Russian units and on board the Mir space station. They have an alarming tendency to catch fire when wet. Organic amines are used on modern scrubbers in nuclear subs and the international space station. They can be regenerated easier as can silver/zinc hydroxides. Personally I'd like to use a microwave plasma for the direct cracking of CO2 back to its elements rather than relying on messy chemistry.
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8th January 2006, 17:14	#8 (permalink)
E-man On the loop! Current Rebreather/s: Inspiration Classic Optima Other Rebreather/s: Titan Join Date: Sep 2005 Location: Eastern Coast ;) Posts: 212	Re: A new type of sorb Don't forget about the price...lime (calcium) is cheap, hence fairly cheap sorb. Lithium isnt cheap. Comes to the problem i see with the extendair absorbents, more efficient use of the calcium, but at a higher cost.
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