ELECTROCHEMICAL GAS GENERATOR FOR COMBUSTIBLE GASES

Abstract

An electrochemical gas generator is provided with an electrolysis cell (1) with a housing, which is closed by a gas-permeable membrane (2) for the escape of the test or calibrating gas. A cathode (5) is provided formed of a noble metal, a mixture of noble metals or a material containing carbon. The cathode is in direct contact with an electrolyte (7) disposed in the housing. An anode (4) is provided formed of a noble metal, a mixture of noble metals or a material containing carbon. The anode is in direct contact with an electrolyte (7). The electrolyte (7) contains a carboxylic acid salt. A control unit (6) is provided that acts as a current source and which is connected to the electrodes (4, 5).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic view showing an electrochemical gas generator for producing ethane, with the view showing the most important components; and

FIG. 2 is a schematic view showing an alternative design of a gas generator for the same test gas.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in particular, an exemplary embodiment of the present invention will be explained below for a gas generator producing ethane by means of FIG. 1, which schematically shows an electrochemical gas generator with the most important components. An alternative design of a gas generator for the same test gas is shown in FIG. 2. Generators of a completely analogous design are used to produce the test gas ethene with succinic acid salts instead of the acetates.

A molding 3 consisting of potassium acetate is reacted electrochemically by means of a platinum mesh connected as an anode 4 in an electrolysis cell 1 with a housing, which is closed by a gas-permeable membrane 2. A platinum electrode is likewise preferably used as the cathode 5. The electrodes 4, 5 are connected to a control unit 6, which may be connected as a potentiostat, but is preferably used as a current source. If electrolysis is carried out now, the following reactions take place at the anode 4:

Anode: 2 H₃C—COO⁻→2 H₃C—COO.+2 e⁻

2 H₃C—COO.→2 H₃C.+2 CO₂ ↑

2 H₃C.→H₃C—CH₃ ↑

Cathodic hydrogen generation takes place when aqueous electrolyte systems are used.

Cathode: 2 H₂O+2e⁻→H₂↑+2OH⁻

The ethane/CO₂ mixture formed at the anode 4 leaves the housing of the electrolysis cell 1 through the permeable membrane 2 and can be used as a test or calibrating gas for gas generators, which are in connection with the test gas or calibrating gas.

FIG. 2 shows another design according to the present invention of the gas generator for ethane. A reference electrode 8 is additionally introduced into the electrolysis cell in direct contact with the electrolyte and is likewise connected to the control unit 6.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

Claims

1. An electrochemical gas generator comprising: an electrolysis cell with a housing closed by a gas-permeable membrane to allow for the escape of a test or a calibrating gas;an electrolyte containing a carboxylic acid salt, said electrolyte being in said housing;a cathode formed of one or more of a noble metal, a mixture of noble metals and a material containing carbon, said cathode being in direct contact with said electrolyte;an anode formed of one or more of a noble metal, a mixture of noble metals, and a material containing carbon, said anode being in direct contact with said electrolyte, anda control unit acting as a current source, said control unit being connected to said cathode and said anode.

2. An electrochemical gas generator in accordance with claim 1, further comprising: a reference electrode present in said electrolysis cell in contact with said electrolyte.

3. An electrochemical gas generator in accordance with claim 1, wherein said control unit includes a potentiostat.

4. An electrochemical gas generator in accordance with claim 1, wherein both said cathode and said anode include platinum and said anode comprises a mesh structure.

5. An electrochemical gas generator in accordance with claim 1, wherein a substance reacted at said anode is at least one of acetic acid, an alkali metal salt, an alkaline earth metal salt and an ammonium salt of acetic acid.

6. An electrochemical gas generator in accordance with claim 5, wherein a substance reacted at said anode is potassium acetate.

7. An electrochemical gas generator in accordance with claim 1, wherein a substance reacted at said anode is at least one of a dicarboxylic acid, an alkali metal salt, an alkaline earth metal salt and an ammonium salt of dicarboxylic acid.

8. An electrochemical gas generator in accordance with claim 1, wherein a substance reacted at said anode is a sodium salt of succinic acid, sodium succinate.

9. An electrochemical gas generator in accordance with claim 1, further comprising a substance reacted at said anode, said substance being in the form of a molding placed on said anode or in the form of a structure compressed around said anode.

10. An electrochemical gas generator in accordance with claim 1, wherein said electrolyte comprises a substance in which the carboxylic acid compound used is poorly soluble.

11. An electrochemical gas generator in accordance with claim 1, wherein said electrolyte is an organic electrolyte formed of a mixture of propylene carbonate and ethylene carbonate.

12. An electrochemical gas generator in accordance with claim 1, wherein said electrolyte comprises a room temperature ionic liquid including imidazolium salts.

13. An electrochemical gas generator in accordance with claim 1, wherein the test or calibrating gas ethane is formed by decarboxylation from a carboxylic acid compound at said anode.

14. An electrochemical gas generator in accordance with claim 9, wherein said anode comprises platinum with a mesh structure; andsaid molding with contacting platinum mesh of said anode directly adjoins said membrane.

15. An electrochemical gas generator in accordance with claim 1, wherein the housing of said electrolysis cell consists of a chemically inert polymer.

16. An electrochemical gas generator in accordance with claim 1, wherein the housing of said electrolysis cell comprises polypropylene.

17. An electrochemical gas generator in accordance with claim 1, wherein said membrane consists of a microporous perfluorinated polymer.

18. An electrochemical gas generator comprising: a gas impermeable housing with an opening;a gas-permeable membrane closing said opening, said gas-permeable membrane allowing for the release of a test gas or a calibrating gas;an electrolyte containing a carboxylic acid salt, said electrolyte being in said housing;a cathode consisting of one or more of a noble metal, a mixture of noble metals and a material containing carbon, said cathode being in direct contact with said electrolyte;an anode consisting of one or more of a noble metal, a mixture of noble metals, and a material containing carbon, said anode being in direct contact with said electrolyte; anda control unit with electrical connections to said cathode and said anode for supplying current to said cathode and said anode in a controlled manner for a controlled generation of a test gas or a calibrating gas.

19. An electrochemical gas generator in accordance with claim 18, further comprising: a substance reacted at said anode, said substance being in the form of a molding placed on said anode or in the form of a structure compressed around said anode wherein:said control unit includes a potentiostat;both said cathode and said anode include platinum and said anode comprises a mesh structure; andsaid molding with contacting platinum mesh of said anode directly adjoins said membrane.

20. An electrochemical gas generator in accordance with claim 19, further comprising: a reference electrode present in said electrolysis cell in contact with said electrolyte.