"On-site" carbon dioxide generator

Abstract

Systems are described for the “on-site” production of substantial amounts of carbon dioxide and hydrogen. The systems include a stack of multiple electrochemical cells, which decompose organic carboxylated compounds into CO2 and H2 without leaving any residue. From a bench-top small generator, producing about 1 lb of CO2 per day to a large-scale generator producing 1 ton of CO2 per day, the process is essentially identical.

Description

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front perspective view of a multi-cell generator stack for producing carbon dioxide and hydrogen from oxalic acid, an organic acid;

FIG. 2A is an exploded perspective view of the various components that make up individual cells;

FIG. 2B is an enlarged schematic front elevation view of an electrochemical cell;

FIG. 3 is a side elevation view of the principal components of a self-contained carbon dioxide generation system;

FIGS. 4A is a schematic cross sectional view of a first version of a multi-cell stack inter-cell connection that generates a mixture of carbon dioxide and hydrogen;

FIG. 4B is a schematic cross sectional view of a second version of a multi-cell stack inter-cell connection that (separately) generates carbon dioxide and hydrogen streams;

FIG. 5 is a schematic cross sectional view of a carbon dioxide generation system in which the hydrogen is allowed to electrochemically react with air within the generator, thereby decreasing the energy required to operate the system;

FIG. 6 is a schematic illustration of a carbon dioxide generator producing mixed carbon dioxide and hydrogen and where the mixture is processed externally to the system to generate pure carbon dioxide and pure hydrogen;

FIGS. 7A is a schematic illustration of a first single cell generator releasing CO₂ and H₂ separately;

FIGS. 7B is a schematic illustration of a second single cell generator releasing CO₂ and H₂ separately;

FIG. 8 is a schematic view of a multi-cell CO₂ generator where one of the generated gases, CO₂ or H₂, is collected separately from the other;

FIG. 9 is a partially exploded schematic view showing the assembly steps of a generator allowing for gas separation; and

FIG. 10 is an exploded schematic perspective view of the individual components used to assemble a gas collection chamber.

Claims

1. A generator having a stack of electrochemical cells for producing carbon dioxide and hydrogen from an organic carboxylated acid solution comprising: at least two individual electrochemical cells; there would be a left end first electrochemical cell and a right end second electrochemical cell;said first and second electrochemical cells being spaced from each other to form a stack having a left end and a right end;said first electrochemical cell comprising a first central ionic conductor member having a left outer surface and a right outer surface; a first left side electrode is pressed against said left outer surface and a first right side electrode is pressed against said right outer surface; said first electrochemical cell being located at said left end of said stack;said second electrochemical cell comprising a second central ionic conductor member having a left outer surface and a right outer surface; a second left side electrode is pressed against said left outer surface and a second right side electrode is pressed against said right outer surface; said second electrochemical cell being located at said right end of said stack;a first current collector means is connected to said first left side electrode and it would have a 1st electrical terminal;a second current collector means is connected to said first right side electrode and it would have a 2nd electrical terminal;a third current collector means is connected to said second left side electrode and it would have a 3rd electrical terminal;said second and third current collectors means being electrically connected to each other in series;a fourth current collector means is connected to said second right side electrode and it would have a 4th electrical terminal;an electrical power source is electrically connected between said 1st electrical terminal and said 4th electrical terminal;a primary container having a reservoir chamber; andan aqueous solution is located in said reservoir chamber; and said stack of electrochemical cells is located in said reservoir chamber;

2. A generator as recited in claim 1 wherein said aqueous solution is an organic acid.

3. A generator as recited in claim 1 wherein said aqueous solution is a solid organic acid.

4. A generator as recited in claim 1 wherein said electrochemical cells are aligned with each other.

5. A generator as recited in claim 1 wherein there is a tab portion extending from each of said current collector means.

6. A generator as recited in claim 1 wherein said current collector means have a grid-like structure whose open spaces allow the aqueous solution to have increased contact with the outer surfaces of said left and right side electrodes.

7. A generator as recited in claim 1 wherein there are more than two electrochemical cells and they each comprise: a central ionic conductor member having a left outer surface; a left side electrode pressed against said left outer surface and a right side electrode pressed against said right side outer surface; a left side current collector is connected to said left side electrode and a right side current collector is connected to said right side current collector.

8. A generator as recited in claim 7 wherein said additional electrochemical cells are positioned between said left end first electrochemical cell and said right end second electrochemical cell; said respective additional left side electrodes and said respective additional right side electrodes of said additional electrochemical cells being electrically connected in series between said first right side electrode and said second left side electrode of said respective left end first electrochemical cell and said respective right end second electrochemical cell.

9. A generator as recited in claim 1 further comprising a left end plate and a right end plate and said pair assemblies of said electrochemical cells are positioned therebetween; a plurality of rod members fasten said left and right end plates together.

10. A generator as recited in claim 9 wherein end plates have numerous open passages to allow said aqueous solution to flow freely therethrough for improved contact with said electrodes of said respective electrochemical cells.

11. A generator as recited in claim 1 further comprising spacer members between said respective electrochemical cells to maintain a predetermined separation between adjacent electrochemical cells.

12. A generator as recited in claim 1 further comprising insulation means for said container so that the temperature of said aqueous solutions will increase during operation of said generator to improve its performance.

13. A generator as recited in claim 1 wherein said aqueous solution is a slurry of anhydrous oxalic acid.

14. A generator as recited in claim 1 wherein said aqueous solution is a slurry of oxalic acid dihydrate.

15. A generator as recited in claim 1 wherein said ionic conductor member is an ion exchange member.

16. A generator as recited in claim 1 wherein said ionic conductor is a porous non-metallic material capable of holding aqueous solution

17. A generator as recited in claim 1 wherein said electrical power source is a DC power source.

18. A generator as recited in claim 17 wherein said DC power source is a battery.

19. A generator as recited in claim 17 wherein said DC power source is an AC/DC converter.

20. A generator as recited in claim 17 wherein said DC power source is a solar photovoltaic cell module.

21. A generator as recited in claim 1 wherein said generator has means for producing an exhaust stream of CO2 and H2 and said exhaust mixed gas stream is connected to means for scrubbing oxalic acid that is present from said exhaust mixed gas stream.

22. A generator as recited in claim 21 further comprising water recycling means for returning water separated from said exhaust mixed gas stream back to said primary container.

23. A generator as recited in claim 21 further comprising means for processing the exhaust gas stream after it has been scrubbed of oxalic acid and next producing substantially pure separated H2 and CO2 gases.

24. A generator as recited in claim 1 further comprising supply means for continuously supplying more aqueous solution that has been consumed by said generator.

25. A generator having a stack of electrochemical cells for producing carbon dioxide and hydrogen from an organic carboxylated acid solution comprising: at least two individual electrochemical cells; there would be a left end first electrochemical cell and a right end second electrochemical cell;said first and second electrochemical cells being spaced from each other to form a stack having a left end and a right end;said first electrochemical cell comprising a first central ionic conductor member having a left outer surface and a right outer surface; a first left side electrode is pressed against said left outer surface and a first right side electrode is pressed against said right outer surface; said first electrochemical cell being located at said left end of said stack;said second electrochemical cell comprising a second central ionic conductor member having a left outer surface and a right outer surface; a second left side electrode is pressed against said left outer surface and a second right side electrode is pressed against said right outer surface; said second electrochemical cell being located at said right end of said stack;said left outer surface and a second right side electrode is pressed against said right outer surface;a primary container having a reservoir chamber;an aqueous solution is located in said reservoir chamber; and said stack of electrochemical cells is located in said reservoir chamber;means forming a secondary container between said first electrochemical cell and said second electrochemical cell; said secondary container having a chamber therein that is watertight to prevent entry of said aqueous solution therein; said secondary container functions to receive hydrogen gas in said chamber from said right outer surface of said first central ionic conductor member and to receive hydrogen gas in said chamber from said left outer surface of said second central ionic conductor member; said secondary container having a hydrogen gas exit port;a first current collector means is connected to said first left side electrode and it would have a 1st electrical terminal;a second current collector means is connected to said first right side electrode and it would have a 2nd electrical terminal;a third current collector means is connected to said second left side electrode and it would have a 3rd electrical terminal;said first and third current collectors means being electrically connected to each other in series;a fourth current collector means is connected to said second right side electrode and it would have a 4th electrical terminal; said second and fourth current collector means being electrically connected to each other in series;an electrical power source having a positive electrical terminal and a negative electrical terminal; one of said terminals is electrically connected to said 1st and 3rd electrical terminals and said other terminal is electrically connected to said 2nd and 4th electrical terminal.

26. A generator as recited in claim 25 wherein said aqueous solution is an organic acid.

27. A generator as recited in claim 25 wherein said aqueous solution is a solid organic acid.

28. A generator as recited in claim 25 wherein said electrochemical cells are aligned with each other.

29. A generator as recited in claim 25 wherein there is a tab portion extending from each of said current collector means.

30. A generator as recited in claim 25 wherein said current collector means have a grid-like structure whose open spaces allow the aqueous solution to have increased contact with the outer surfaces of said left and right side electrodes.

31. A generator as recited in claim 25 wherein said first and second electrochemical cells form a first pair assembly and there are a plurality of said pair assemblies and they each have two electrochemical cells and each comprise: a central ionic conductor member having a left outer surface; a left side electrode pressed against said left outer surface and a right side electrode pressed against said right side outer surface; a left side current collector is connected to said left side electrode and a right side current collector is connected to said right side current collector.

32. A generator as recited in claim 31 wherein said additional pair assemblies are laterally spaced from each other and said first pair assembly to form a stack.

33. A generator as recited in claim 31 further comprising a left end plate and a right end plate and said pair assemblies of said electrochemical cells are positioned therebetween; a plurality of rod members fasten said left and right end plates together.

34. A generator as recited in claim 33 wherein end plates have numerous open passages to allow said aqueous solution to flow freely therethrough for improved contact with said electrodes of said respective electrochemical cells.

35. A generator as recited in claim 25 further comprising spacer members between said respective pair assemblies to maintain a predetermined separation between adjacent pair assemblies.

36. A generator as recited in claim 26 further comprising insulation means for said container so that the temperature of said aqueous solution will increase during operation of said generator to improve its performance.

37. A generator as recited in claim 27 wherein said aqueous solution is a slurry of anhydrous oxalic acid.

38. A generator as recited in claim 25 wherein said aqueous solution a slurry of oxalic acid dihydrate.

39. A generator as recited in claim 25 wherein said ionic conductor member is an ion exchange membrane.

40. A generator as recited in claim 25 wherein said ionic conductor is a porous non-metallic material capable of holding aqueous solution.

41. A generator as recited in claim 25 wherein said electrical power source is a DC power source.

42. A generator as recited in claim 41 wherein said DC power source is a battery.

43. A generator as recited in claim 41 wherein said DC power source is an AC/DC converter.

44. A generator as recited in claim 31 wherein said DC power source is a solar photovoltaic cell module.

45. A generator as recited in claim 25 wherein said generator has means for producing separate gas streams of CO2 and H2 and said exhaust streams are connected to means for scrubbing oxalic acid that is present from said exhaust gas streams.

46. A generator as recited in claim 45 further comprising water recycling for returning water separated from said exhaust gas streams back to said primary container.

47. A generator as recited in claim 45 further comprising means for processing the exhaust gas streams after they have been scrubbed of oxalic acid and next producing substantially pure separated H2 and CO2 gases.

48. A generator as recited in claim 25 further comprising supply means for continuously supplying more aqueous solution to said primary container to replace aqueous solution that has been consumed by said generator.

49. A generator having a stack of electrochemical cells for producing carbon dioxide and hydrogen from an organic carboxylated acid solution comprising: at least a pair of individual electrochemical cells; there would be a left end first electrochemical cell and a right end second electrochemical cell;said first and second electrochemical cells being spaced from each other to form a stack having a left end and a right end;said first electrochemical cell comprising a first central ionic conductor member having a left outer surface and a right outer surface; a first left side electrode is pressed against said left outer surface and a first right side electrode is pressed against said right outer surface; said first electrochemical cell being located at said left end of said stack;said second electrochemical cell comprising a second central ionic conductor member having a left outer surface and a right outer surface; a second left side electrode is pressed against said left outer surface and a second right side electrode is pressed against said right outer surface; said second electrochemical cell being located at said right end of said stack;a primary container having a reservoir chamber;an aqueous solution is located in said reservoir chamber; and said stack of electrochemical cells is located in said reservoir chamber;means forming a secondary container between said first electrochemical cell and said second electrochemical cell; said secondary container having a chamber therein that is watertight to prevent entry of said aqueous solution therein; said secondary container functions to receive hydrogen gas in said chamber from said right outer surface of said first central ionic conductor member and to receive hydrogen gas in said chamber from said left outer surface of said second central ionic conductor member; said secondary container having an air inlet port; said secondary container having an open top end through which the mixed gas of hydrogen and air are free to escape.a first current collector means is connected to said first left side electrode and it would have a 1st electrical terminal;a second current collector means is connected to said first right side electrode and it would have a 2nd electrical terminal;a third current collector means is connected to said second left side electrode and it would have a 3rd electrical terminal;said first and third current collectors means being electrically connected to each other in series;a fourth current collector means is connected to said second right side electrode and it would have a 4th electrical terminal; said second and fourth current collector means being electrically connected to each other in series; andan electrical power source having a positive electrical terminal and a negative electrical terminal; one of said terminals is electrically connected to said 1st and 3rd electrical terminals and said other terminal is electrically connected to said 2nd and 4th electrical terminals.

50. A generator as recited in claim 49 wherein said aqueous solution is an organic acid.

51. A generator as recited in claim 49 wherein said aqueous solution contains a solid organic acid.

52. A generator as recited in claim 49 wherein said electrochemical cells are aligned with each other.

53. A generator as recited in claim 49 wherein there is a tab portion extending from each of said current collector means.

54. A generator as recited in claim 49 wherein said current collector means have a grid-like structure whose open spaces allow the aqueous solution to have increased contact with the outer surfaces of said left and right side electrodes.

55. A generator as recited in claim 49 wherein said first and second electrochemical cells form a first pair assembly and there are a plurality of said pair assemblies and they each have two electrochemical cells and each comprise: a central ionic conductor member having a left outer surface; a left side electrode pressed against said left outer surface and a right side electrode pressed against said right side outer surface; a left side current collector is connected to said left side electrode and a right side current collector is connected to said right side current collector.

56. A generator as recited in claim 55 wherein said additional pair assemblies are laterally spaced from each other and said first pair assembly to form a stack.

57. A generator as recited in claim 55 further comprising a left end plate and a right end plate and said pair assemblies of said electrochemical cells are positioned therebetween; a plurality of rod members fasten said left and right end plates together.

58. A generator as recited in claim 57 wherein end plates have numerous open passages to allow said aqueous solution to flow freely therethrough for improved contact with said electrodes of said respective electrochemical cells.

59. A generator as recited in claim 49 further comprising spacer members between said respective pair assemblies to maintain a predetermined separation between adjacent pair assemblies.

60. A generator as recited in claim 49 further comprising insulation means for said container so that the temperature of said aqueous solution will increase during operation of said generator to improve its performance.

61. A generator as recited in claim 49 wherein said aqueous solution is a slurry of anhydrous oxalic acid.

62. A generator as recited in claim 49 wherein said aqueous solution a slurry of oxalic acid dihydrate.

63. A generator as recited in claim 49 wherein said ionic conductor member is an ion exchange membrane.

64. A generator as recited in claim 49 wherein said ionic conductor is a porous non-metallic material capable of holding aqueous solution.

65. A generator as recited in claim 49 wherein said electrical power source is a DC power source.

66. A generator as recited in claim 65 wherein said DC power source is a battery.

67. A generator as recited in claim 65 wherein said DC power source is an AC/DC converter.

68. A generator as recited in claim 65 wherein said DC power source is a solar photovoltaic cell module.

69. A generator as recited in claim 49 wherein said generator has means for producing an exhaust stream of CO2 and separately a H2 depleted gas stream mixed with excess air, and said exhaust mixed gas streams are connected to means for scrubbing oxalic acid that is present from said exhaust gas streams.

70. A generator as recited in claim 69 further comprising water recycling means for returning water separated from said exhaust gas streams back to said primary container.

71. A generator as recited in claim 69 further comprising means for processing the exhaust gas streams after they have been scrubbed of oxalic acid and next producing substantially a pure CO2 gas stream.

72. A generator as recited in claim 49 further comprising supply means for continuously supplying more aqueous solution that has been consumed by said generator.

73. A generator producing carbon dioxide and hydrogen from an organic carboxylated acid solution comprising: a container having a bottom wall, upstanding surrounding side walls and a top wall enclosing said side walls;an upright oriented electrochemical cell module having structure for decomposing an organic acid, said electrochemical cell module having a left side surface, a right side surface and an upright oriented peripheral side edge;an upright oriented partition wall extends downwardly from said top wall of said container across the width of said container to form a distinct first chamber and a distinct second chamber; said peripheral side edge of said electrochemical cell module is incorporated in said partition wall; said partition wall does not fully extend to the bottom of said container to allow for liquid motion between said first chamber and said second chamber without allowing gases to escape into the adjacent chambers; said first chamber having a carbon dioxide exit port and said second chamber having a hydrogen gas exit port;said electrochemical cell module having a cathode and an anode;a d.c. electrical power supply; anda primary electrical circuit connecting said anode and cathode to said d.c. electrical power supply to provide energy for generating carbon dioxide in said first chamber and hydrogen in said second chamber from an organic acid solution that would immerse said electrochemical cell module in said container.

74. A generator producing carbon dioxide and hydrogen from an organic carboxylated acid solution comprising: a container having a bottom wall, upstanding surrounding side walls and a top wall enclosing said side walls;an upright oriented electrochemical cell module having structure for decomposing an organic acid, said electrochemical cell module having a left side surface, a right side surface and an upright oriented peripheral side edge;an upright oriented partition wall extends downwardly from said top wall of said container across the width of said container to form a distinct first chamber and a distinct second chamber; said peripheral side edge of said electrochemical cell module is incorporated in said partition wall; said partition wall also fully extends to the bottom of said container to provide complete separation between said first chamber and said second chamber; said first chamber having a carbon dioxide exit port and said second chamber having a hydrogen gas exit port;said electrochemical cell module having a cathode and an anode;a d.c. electrical power supply; anda primary electrical circuit connecting said anode and cathode to said d.c. electrical power supply to provide energy for generating carbon dioxide in said first chamber and hydrogen in said second chamber from an organic acid solution that would only be present in said first chamber and said organic acid solution would only immerse said left side surface of said electrochemical cell module in said container because hydrogen gas evolution from said right side surface of said electrochemical cell module does not require the presence of any organic acid solution in said second chamber.