Hydrogen generating apparatus

• US 4,093,527 A
• Filed: 11/26/1975
• Issued: 06/06/1978
• Est. Priority Date: 12/13/1974
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Uenishi, Akira, Honda, Takashi, Furutani, Yasumasa, Tanno, Kazuo
• Primary Examiner(s): Prescott, Arthur C.
• Application Number:
  US05/635,362
• Time in Patent Office: 923 Days
• Field of Search: 204/180 P, 204/301, 204/DIG. 4, 204/DIG. 3, 204/129, 429/101, 429/105, 429/106
• US Class Current: 205/637
• CPC Class Codes: C25B 1/02 Hydrogen or oxygen
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y02P 20/133 Renewable energy sources, e.g. sunlight
• CPC Class Codes: Y10S 204/03 Auxiliary internally generated electrical energy
• CPC Class Codes: Y10S 204/04 Electrolysis cell combined with fuel cell

Abstract

A hydrogen generating apparatus comprising a cell having a plurality of chambers defined in the cell by cation exchange membranes and anion exchange membranes arranged alternately, a high concentration electrolyte and a low concentration electrolyte being filled alternately in said plurality of chambers, and a pair of electrodes guided into the chambers disposed on both the ends of said cell, respectively, and the open circuit voltage between said electrodes being higher than the decomposition voltage of water.

Claims

1. A hydrogen generating method, comprising:

(1) providing a cell having a casing, and first and second electrodes on the opposite ends of said casing;

(2) providing a plurality of cation and anion exchange membranes disposed in said casing in a manner that said cation and anion exchange membranes are alternately arranged between said electrodes and are spaced from each other to define a plurality of chambers, with each chamber constituting the space encompassed by a cation exchange membrane, an adjacent anion exchange membrane and said casing, and electrically isolating with said casing and membranes each chamber from the adjacent chambers and transferring only cations and anions from one chamber to an adjacent chamber through the respective membranes;

(3) introducing a first aqueous electrolyte into every other one of said chambers;

(4) introducing a second aqueous electrolyte of the same kind as said first electrolyte into said other chambers, while maintaining the second electrolyte at a concentration lower than that of the first electrolyte;

(5) heating part of the first electrolyte outside of said chambers to concentrate the first electrolyte by vaporizing water therein and removing the vaporized water from the first electrolyte;

(6) introducing water into said other chambers containing the second electrolyte to dilute the second electrolyte so as to maintain a predetermined concentration difference between the first and second electrolytes; and

(7) maintaining the number of said chambers at least enough so that the sum of the theoretical decomposition voltage of water to be generated across said electrodes, a voltage drop due to the hydrogen over-voltage determined by the material of said electrodes and a voltage drop due to the interior resistance of the cell is high enough to decompose the water in the electrolyte to generate hydrogen at one of said electrodes when said electrodes are electrically interconnected in an electrical path electrically parallel to the chambers.

2. The hydrogen generating method of claim 1, wherein said step of heating employs solar energy as its energy source.

3. The hydrogen generating method of claim 1, wherein said step of heating employs waste exhaust heat as its energy source.

4. The hydrogen generating method of claim 1, wherein said step of heating employs a low density energy as its energy source.

5. The hydrogen generating method of claim 1, wherein said step of introducing water employs the water removed by said step of heating and additional makeup water to replace the water consumed in the generation of hydrogen.

6. A hydrogen generating apparatus, comprising:

(1) a cell having a casing, and first and second electrodes on the opposite ends of said casing;

(2) a plurality of cation and anion exchange membranes disposed in said casing in a manner that said cation and anion exchange membranes are alternately arranged between said electrodes and are spaced from each other to define a plurality of chambers, with each chamber constituting the space encompassed by a cation exchange membrane, an adjacent anion exchange membrane and said casing, said casing and membranes including means to electrically isolate each chamber from the adjacent chambers and further to permit transferrence of only cations and anions from one chamber to an adjacent chamber through the respective membranes;

(3) means fluid connected with every other one of said chambers to introduce a first aqueous electrolyte into every other one of said chambers;

(4) means fluid connected to the other of said chambers to introduce a second aqueous electrolyte of the same kind as the first electrolyte into said other chambers, with the second electrolyte having a concentration lower than that of the first electrolyte.

(5) concentrating means to heat part of the first electrolyte outside of said chambers to concentrate the first electrolyte by vaporizing water therein and removing the vaporized water from the first electrolyte;

(6) diluting means to introduce water into said other chambers containing the second electrolyte to dilute the second electrolyte so as to maintain a predetermined concentration difference between the first and second electrolyte; and

(7) the number of said chambers being at least enough so that the sum of the theoretical decomposition voltage of water to be generated across said electrodes, a voltage drop due to the hydrogen over-voltage determined by the material of said electrodes and a voltage drop due to the interior resistance of the cell is high enough to decompose the water in the electrolyte to generate hydrogen gas at one of said electrodes when said electrodes are electrically interconnected in an electrical path electrically parallel to the chambers.

7. A hydrogen generating apparatus as set forth in claim 6, wherein said concentrating means to heat employs a low density energy source.

8. The hydrogen generating apparatus of claim 6, wherein said concentrating means to heat employs solar energy as its energy source.

9. The hydrogen generating apparatus of claim 6, wherein said concentrating means to heat employs waste exhaust heat as its energy source.

10. The hydrogen generating apparatus of claim 6, wherein said diluting means obtains the water, removed by said concentrating means and introduced it into said other chambers, and further including means supplying makeup water to the chambers to replace the water consumed in the generation of hydrogen.

11. The hydrogen generating apparatus as set forth in claim 6, including a first aqueous electrolyte filling said every other one of said chambers;

and a second aqueous electrolyte filling said other chambers and having a cation and anion ion concentration of the same kind as said first electrolyte and of a concentration substantially lower than the concentration of said first electrolyte.

12. A hydrogen generating apparatus as set forth in claim 6, wherein each of said electrodes is composed of a material selected from the group consisting of gold, platinum, iron, nickel and graphite.

13. A hydrogen generating apparatus as set forth in claim 6, including first and second electrolytes respectively within said chambers which comprise an electrolyte in which the cation is the ion of a metal selected from the group consisting of alkali metals and alkaline earth metals.