IL33705A - Atmospheric control utilizing an electrolytic carbon dioxide concentrator - Google Patents
Atmospheric control utilizing an electrolytic carbon dioxide concentratorInfo
- Publication number
- IL33705A IL33705A IL33705A IL3370570A IL33705A IL 33705 A IL33705 A IL 33705A IL 33705 A IL33705 A IL 33705A IL 3370570 A IL3370570 A IL 3370570A IL 33705 A IL33705 A IL 33705A
- Authority
- IL
- Israel
- Prior art keywords
- carbon dioxide
- cell
- cathode
- hydrogen
- electrolyte
- Prior art date
Links
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims description 108
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims description 62
- 239000001569 carbon dioxide Substances 0.000 title claims description 54
- 239000003792 electrolyte Substances 0.000 claims description 24
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 23
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 23
- 239000001257 hydrogen Substances 0.000 claims description 19
- 229910052739 hydrogen Inorganic materials 0.000 claims description 19
- 239000007789 gas Substances 0.000 claims description 14
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 13
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 12
- 239000001301 oxygen Substances 0.000 claims description 12
- 229910052760 oxygen Inorganic materials 0.000 claims description 12
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical group [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 10
- 239000007864 aqueous solution Substances 0.000 claims description 7
- 238000005868 electrolysis reaction Methods 0.000 claims description 7
- 150000002500 ions Chemical class 0.000 claims description 7
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical group [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 150000002431 hydrogen Chemical class 0.000 claims description 3
- 229910000288 alkali metal carbonate Inorganic materials 0.000 claims description 2
- 150000008041 alkali metal carbonates Chemical class 0.000 claims description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 2
- 239000008246 gaseous mixture Substances 0.000 claims 3
- 238000005260 corrosion Methods 0.000 claims 1
- 230000007797 corrosion Effects 0.000 claims 1
- 238000010494 dissociation reaction Methods 0.000 claims 1
- 230000005593 dissociations Effects 0.000 claims 1
- 230000001172 regenerating effect Effects 0.000 description 5
- 239000010425 asbestos Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052895 riebeckite Inorganic materials 0.000 description 4
- 239000011159 matrix material Substances 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 230000029058 respiratory gaseous exchange Effects 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 2
- -1 for example Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 230000000241 respiratory effect Effects 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- FJDQFPXHSGXQBY-UHFFFAOYSA-L caesium carbonate Chemical compound [Cs+].[Cs+].[O-]C([O-])=O FJDQFPXHSGXQBY-UHFFFAOYSA-L 0.000 description 1
- 229910000024 caesium carbonate Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 239000002001 electrolyte material Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000003014 ion exchange membrane Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 1
- 229910052808 lithium carbonate Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000009428 plumbing Methods 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000012047 saturated solution Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Landscapes
- Gas Separation By Absorption (AREA)
- Treating Waste Gases (AREA)
Description
ATMOSPHERIC CONTROL 0TILIZIN0 AN ELECTROLYTIC CARBON DIOXIDE CONCENTRATOR. ta a mm Tut pip»n fpnm no»» The present invention relates to a method and apparatus for atmosphere control, and specifically it is directed to means for reducing the amount of carbon dioxide in air for respiratory purposes . While not limited thereto, the method and apparatus of the present invention are particularly adaptable to closed cycle environments which require the recirculation of air, with replenishment of the oxygen content, and diminution of the carbon dioxide as, for example, in underground habitations, submarines and the like.
The removal of carbon dioxide from air necessitates a concentration of the carbon dioxide content to a level at which it is feasible to process it.
The present invention provides a system for the regeneration of oxygen from carbon dioxide in either a closed regenerative life support system or a non-regenerative life support system, utilizing an electrolytic concentration cell for the removal and concentration of carbon dioxide from the atmosphere.
One of the objects of the present invention is to provide an improved method for removing carbon dioxide from admixture with gases, particularly from admixture with oxygen and nitrogen in air.
Another object of the invention is to provide a method for separating carbon dioxide from air and then reducing the carbon dioxide to produce oxygen for breathing purposes, A further object of the invention is to provide an apparatus for the efficient concentration of carbon dioxide utilizing a concentration cell which is depolarized by the introduction of hydrogen gas.
Still another object of the invention is to provide confined space, while recovering the carbon dioxide and reducing the same to produce oxygen used up during the respiratory processes.
In accordance with the present invention, we provide an electrolytic cell for concentrating carbon dioxide, the cell being depolarized by means of hydrogen. The cell employs a carbonate electrolyte, typically an aqueous solution of an alkali metal carbonate such as potassium carbonate or sodium carbonate.
The principle!, of the concentration cell of the present invention may be represented schematically by the following: CO, electrolyte M, C02 M 02(a P¾), C02(a P^) where (a P) is the anode partial pressure of the indicated gas, (c P) is the cathode partial pressure of the indicated gas, and M is a metallic electrode The use of CO^ ions in the schematic, and in the equations that follow is not to be interpreted as if CO^ ions are exclusively the transport specie. It should be understood that the transport process will depend upon the concentrations of carbonate and bicarbonate ions which are in equilibrium with carbon dioxide introduced into the cathode, e.g., for HCO^ ions predominating in solution the . following reaction scheme applies: Cathode: 4C02 + 02 + 2H20 + 4-e HC0^ Anode : 4C02 + 02 + 2H20 + e The individual reactions for the carbonate cell are given in the following equations: Cathode: 2 C02 + 02 + .e"» 2 CO^ Anode: 2 CO^ = 2 C02 + 02 + e" Net: 2 C02(c PCQ ) + 02 (c PQ ) - 2 C02 + Thus, the net reaction is the spontaneous transfer of carbon dioxide and oxygen from cathode to anode of the cell, provided that the following relationship exists: The electrical potential generated by the above reaction is proportional to the difference: c pco2 x c po2 - a pco2 x a po2 And since a maximum is reached when the quantity (a Pn ) approaches zero, the most efficient mode of opera- u2 tion occurs when the anode is depolarized by a fuel, for example, hydrogen.
The reactions occurring for the depolarized mode of operation are listed below: Cathode: 0 + 2 C0 + e~ » 2 C02s Anode : C05 + 2 H2 = 2 CO- + 2 H¾0 + - e Net: C02(c ?QQ ) + <½ + 2 ≥ » C02 (a P00 ) + 2 H20 A further description of the present invention will be made in conjunction with the attached sheet of drawings in which: present invention; Figure 2 is a schematic representation of a non-regenerative life support system employing the improvements of the present invention; and Figure 3 is a somewhat schematic view of the improved electrolytic carbon dioxide concentrator employed with either of the systems of Figures 1 or 2.
In Figure 1 , reference numeral 10 indicates generally an electrolytic carbon dioxide concentrator which forms one of the principal features of the present invention. The specific details of the concentrator 10 are best shown in Figure 3 of the drawings. As seen in that figure, the concentrator 10 includes a cathode 11 , and an anode 12 spaced therefrom by means of an electrolyte 13» In the illustrated form of the invention, the electrolyte 13 consists of a matrix of asbestos fibers which has been impregnated with a carbonate solution, such as a five normal solution of potassium carbonate. The electrodes 11 and 12 are connected to an external load such as a battery 1 or a resistance.
Air is introduced against the cathode 11 through a line 16* The carbon dioxide and oxygen from the air is then transported through the electrolyte 13 in the form of carbonate ions. These ions then react with hydrogen gas introduced into the anode compartment through a line 17· The re-action takes place at the anode gas-electrolyte interface to produce pure carbon dioxide and water which, together with the unreacted hydrogen, is withdrawn from the anode space by means of a line 18* The air which has become depleted in carbon dioxide is withdrawn from the cathode space by means of a line 19. dioxide, hydrogen, and water vapor withdrawn from the electrolytic carbon dioxide concentrator cell 10 through the line 18 are introduced into a water condenser and separator 21 from which liquid water is withdrawn by means of a line 22. The liquid water passes to an electrolysis cell 23 where it is electrolytically dissociated into hydrogen gas (which passes out through the line 17 into the concentrator 10) and oxygen gas which is delivered to the breathing space by means of a line 24.
After the removal of the water vapor from the mixture in the separator 21 the remaining carbon dioxide and hydrogen are passed by means of a line 26 into a carbon dioxide reduction reactor 27. In this reactor 27, the carbon dioxide and hydrogen are reacted at temperatures of about 1100 to 14-00°F. in the presence of an iron catalyst to produce carbon and water. The carbon may be periodically withdrawn by means of a line 28, while the water evolved may be passed by means of a line 9 into the condenser and separator 21 for further condensation and subsequent electrolysis to hydrogen and oxygen.
In the non-regenerative system shown in Figure 2 of the drawings, reference numeral 31 has been applied to an electrolytic carbon dioxide concentrator which may be identical to that shown in Figure 3 of the drawings. Air is in-troduced into the concentrator by means of a line 32, and hydrogen gas is introduced by means of a line 33. The air from which the carbon dioxide has been extracted is passed to the breathing space 34 for reconstitution with additional amounts of oxygen.
The hydrogen fed to the concentrator 31 through the t sources of water are provided for the cell 36 , one being make-up water introduced through a line 37 , and the other being condensed water introduced through a line 38 and formed in a water condenser separator stage 39. The input to this stage consists of the carbon dioxide, hydrogen gas, and water vapor emanating from the concentrator 31 , and passing through a line 4-1 into the separator 39. The non-condensable gases , consisting of the carbon dioxide and hydrogen in this form of the invention may be vented by means of a line 42 or otherwise disposed of.
The specific concentration cell shown in Figure 3 of the drawings may be modified considerably from the specific form shown therein. The cell electrolyte may be an aqueous solution of an alkaline carbonate immobilized in a suitable matrix such as an asbestos diaphragm, or it may consist of a molten salt electrolyte, or even an ion-exchange membrane. While potassium carbonate is the preferred electrolyte material, it is also possible to use an aqueous solution of either a carbonate or a bicarbonate, since any aqueous solution contains an equilibrium concentration of both. Sodium bicarbonate and lithium carbonate are comparatively insoluble, so that saturated solutions of these salts will normally be used. Cesium carbonate can also be employed, but. is quite expensive.
The electrodes should be chosen so as to be compatible with the electrolyte, that is, not corroded by the electrolyte. Actually, any combination of metals or metals on substrates may be employed, for example, pressed or sintered metal electrodes, or screen supported metal elec-trodes. nature of the cell. Typical conditions when using platinum electrodes and a potassium carbonate-asbestos matrix electro lyte include voltages ranging from about 1.00 to 0.30 volts, and current densities ranging from about 0 , 00 to 125 ASP. The temperatures may vary widely, ranging from about room temperature to temperatures up to the volatilization point of the electrolyte.
In a specific embodiment of the invention, a concentration cell was made up wherein the electrodes consisted of a mixture of platinum black and polytetrafluoroethylene pressed into a wire mesh screen. The electrolyte was composed of an asbestos diaphragm saturated with an aqueous solution of potassium carbonate. The cell was operated for several hours on air containing 0.5% carbon dioxide. The power density at the end of 8 hours was 10 watts per square foot at 0.46 volts. The effluent-anode gas (non-condensi-bles) was a mixture of 44% carbon dioxide and 56% hydrogen.
The regenerative life support system of the present invention has several distinct advantages. For one, there is a net reduction in power requirements for the system.
For another, continuous processing of the carbon dioxide is possible. In addition, there is a reduction in the complexity of the system insofar as plumbing, controls and gas separation schemes are concerned. Furthermore, the system can be made lightweight and with a small volume.
Claims (10)
1. The method of separating carbon dioxide from admixture with other gases which comprises providing an anode and a cathode with a carbonate electrolyte therebetween, contacting the cathode with a gaseous mixture containing carbon dioxide whereby the carbon dioxide present is transported through said electrolyte in the form of carbonate ions, contacting the anode with hydrogen gas to thereby convert said ions into carbon dioxide and water, and collecting the carbon dioxide depleted gas from the vicinity of said cathode.
2. The method of separating carbon dioxide from a gaseous mixture which comprises providing an aqueous solution of :ah alkaline carbonate electrolyte between a corrosion resistant anode and cathode, contacting the cathode with said gaseous mixture whereby the carbon dioxide present is transported through said electrolyte in the form of carbonate ions, contacting the anode with hydrogen gas to thereby convert said ions into carbon dioxide and water, and collecting the carbon dioxide depleted gas from the vicinity of said cathode.
3. The method of claim 2 in which said electrolyte is potassium carbonate.
4. The method of claim 2 in which said electrolyte is sodium carbonate.
5. The method of removing carbon dioxide from air which comprises subjecting water to electrolysis in an electrolysis zone to produce oxygen and hydrogen gases, passing the air to be treated to the cathode of a concentration cell containing an anode, a cathode, and a carbonate electrolyte therebetween, passing the hydrogen gas pro the carbon dioxide present is transported through said electrolyte in the form of carbonate ions and said ions are converted to carbon dioxide and water by reaction with said hydrogen, recovering the carbon dioxide depleted air from said cell, condensing the water produced in said cell, and passing the condensed water to said electrolysis cell for further dissociation into hydrogen and oxygen gases*
6. The method of claim 5 in which the carbon dioxide and hydrogen recovered from said cell are reacted to form carbon and water.
7. An apparatus for separating carbon dioxide from admixture with other gases which comprises a concentration cell having an anode, a cathode, and a carbonate electrolyte therebetween, means for introducing the carbon dioxide containing mixture to the cathode of said cell, means for introducing hydrogen to the anode of said cell, and means for collecting the carbon dioxide depleted gas from said cell.
8. The apparatus of claim 7 in which said electrolyte consists of a non-conductive member impregnated with an aqueous solution of an alkali metal carbonate.
9. An apparatus for removing carbon dioxide from air which comprises a concentration cell including an anode, a cathode, and a carbonate electrolyte therebetween, means for introducing air containing carbon dioxide to the cathode of said cell, electrolysis means arranged to produce oxygen and hydrogen gases from water, means for delivering the hydrogen thus produced to the anode of said cell, means for withdrawing the carbon dioxide depleted air from said cell, and means for delivering the water produced in said cell to said electrolysis means. i
10. The apparatus of claim 9 which also includes a reduction reactor operating to react carbon dioxide and hydrogen to produce carbon and water therefrom, and means for delivering the carbon dioxide and hydrogen recovered from said cell to said reactor. FOR AND ON BEHALF OF APPLICANTS
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL33705A IL33705A (en) | 1970-01-14 | 1970-01-14 | Atmospheric control utilizing an electrolytic carbon dioxide concentrator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL33705A IL33705A (en) | 1970-01-14 | 1970-01-14 | Atmospheric control utilizing an electrolytic carbon dioxide concentrator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| IL33705A0 IL33705A0 (en) | 1970-03-22 |
| IL33705A true IL33705A (en) | 1972-09-28 |
Family
ID=11045239
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IL33705A IL33705A (en) | 1970-01-14 | 1970-01-14 | Atmospheric control utilizing an electrolytic carbon dioxide concentrator |
Country Status (1)
| Country | Link |
|---|---|
| IL (1) | IL33705A (en) |
-
1970
- 1970-01-14 IL IL33705A patent/IL33705A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| IL33705A0 (en) | 1970-03-22 |
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