Process and apparatus for the production of hydrogen

Abstract

A process and apparatus for the production of hydrogen There is provided a process for the production of hydrogen, the process comprising: electrolysing water in an electrolytic cell to produce hydrogen gas and oxygen gas, the electrolytic cell having a first outlet for hydrogen gas; passing the hydrogen gas from the first outlet of the electrolytic cell to a reaction chamber, the reaction chamber comprising a first inlet for receiving the hydrogen gas from the electrolytic cell and a second outlet for hydrogen gas passing out of the reaction chamber, the reaction chamber containing one or more pieces of a metal or an alloy thereof at least partially submerged in an alkali solution, wherein the first inlet is arranged so that the hydrogen gas bubbles through the alkali solution; passing the hydrogen gas from the second outlet to a gas-cleaning chamber, the gas-cleaning chamber comprising a second inlet for receiving hydrogen gas from the reaction chamber and a third outlet for hydrogen gas passing out of the cleaning chamber, the gas-cleaning chamber containing an aqueous solution, wherein the second inlet is arranged so that the hydrogen gas bubbles through the aqueous solution; and recovering hydrogen gas from the third outlet.

Claims

1. A process for the production of hydrogen, the process comprising: electrolysing water in an electrolytic cell to produce hydrogen gas and oxygen gas, the electrolytic cell having a first outlet for hydrogen gas; passing the hydrogen gas from the first outlet of the electrolytic cell to a reaction chamber, the reaction chamber comprising a first inlet for receiving the hydrogen gas from the electrolytic cell and a second outlet for hydrogen gas passing out of the reaction chamber, the reaction chamber containing one or more pieces of a metal or an alloy thereof at least partially submerged in an alkali solution, wherein the first inlet is arranged so that the hydrogen gas bubbles through the alkali solution; passing the hydrogen gas from the second outlet to a gas-cleaning chamber, the gas-cleaning chamber comprising a second inlet for receiving hydrogen gas from the reaction chamber and a third outlet for hydrogen gas passing out of the cleaning chamber, the gas-cleaning chamber containing an aqueous solution, wherein the second inlet is arranged so that the hydrogen gas bubbles through the aqueous solution; and recovering hydrogen gas from the third outlet.

2. A process according to claim 1, wherein the electrolytic cell contains an ionic solution having a conductivity of at least 0.25 S/cm.

3. A process according to claim 2, wherein the ionic solution comprises KOH(aq) having a concentration of at least 0.3 M.

4. A process according to claim 2, the ionic solution comprises Aluminium Hydroxide, or a metal hydroxide recovered from the reaction chamber, in a concentration of at least 0.0001 M.

5. A process according to claim 1, wherein the process further comprises recovering oxygen from the electrolytic cell.

6. A process according to claim 1, wherein the metal or alloy thereof comprises Aluminium.

7. A process according to claim 1, wherein the metal or alloy thereof is a scrap metal.

8. A process according to claim 1, wherein the reaction chamber contains a plurality of pieces of metal or alloy thereof, each have a weight of less than 0.1 kg.

9. A process according to claim 1, wherein the alkali solution comprises NaOH or KOH.

10. A process according to claim 1, wherein the process further comprises recovering a metal oxide or metal hydroxide from the reaction chamber.

11. A process according to claim 10, wherein the process further comprises treating the metal oxide or metal hydroxide to recover the metal.

12. A process according to claim 1, wherein the process further comprises recycling spent aqueous solution from the gas-cleaning chamber to the electrolytic cell.

13. An apparatus for producing hydrogen, the apparatus comprising: an electrolytic cell for the electrolysis of water to produce hydrogen and oxygen gas, the electrolytic cell having a first outlet for hydrogen gas; a reaction chamber comprising a first inlet in fluid communication with the first outlet, and a second outlet; and a gas-cleaning chamber comprising a second inlet in fluid communication with the second outlet, and a third outlet for the produced hydrogen gas, wherein the reaction chamber contains one or more pieces of a metal or an alloy thereof at least partially submerged in an alkali solution, and wherein the first inlet is for bubbling hydrogen gas through the alkali solution; wherein the gas-cleaning chamber contains an aqueous solution, and wherein the second inlet is for bubbling hydrogen gas through the aqueous solution.

14. An apparatus according to claim 13, wherein the electrolytic cell further comprises a magnetron for treating water within the electrolytic cell.

15. An apparatus according to claim 13, wherein the electrolytic cell comprises a cathode and an anode and a plurality of neutral plates arranged therebetween, each neutral plate being separated from each adjacent neutral plate by a volume for holding an electrolytic solution, wherein said volume contains a mesh membrane to thereby define a cathode-side volume and an anode-side volume, wherein each cathode-side volume is in fluid communication with the first outlet, and wherein the mesh membrane is substantially impervious to gaseous oxygen and hydrogen.

16. An apparatus according to claim 15, wherein the mesh membrane is a nylon mesh membrane.

17. An apparatus according to claim 13, further comprising a flashback arrestor arranged between and in fluid communication with the first outlet and the first inlet.

18. An apparatus according to claim 13, wherein the apparatus comprises a plurality of interchangeable reaction chambers.

19. An apparatus according to claim 18, further comprising a first sensor in communication with the first inlet and a second sensor in communication with the second outlet, wherein the first and second sensors are for determining hydrogen gas flow-rates.

20. An apparatus according to claim 13, wherein the apparatus is for a process for the production of hydrogen comprising: electrolysing water in an electrolytic cell to produce hydrogen gas and oxygen gas, the electrolytic cell having a first outlet for hydrogen gas; passing the hydrogen gas from the first outlet of the electrolytic cell to a reaction chamber, the reaction chamber comprising a first inlet for receiving the hydrogen gas from the electrolytic cell and a second outlet for hydrogen gas passing out of the reaction chamber, the reaction chamber containing one or more pieces of a metal or an alloy thereof at least partially submerged in an alkali solution, wherein the first inlet is arranged so that the hydrogen gas bubbles through the alkali solution; passing the hydrogen gas from the second outlet to a gas-cleaning chamber, the gas-cleaning chamber comprising a second inlet for receiving hydrogen gas from the reaction chamber and a third outlet for hydrogen gas passing out of the cleaning chamber, the gas-cleaning chamber containing an aqueous solution, wherein the second inlet is arranged so that the hydrogen gas bubbles through the aqueous solution; and recovering hydrogen gas from the third outlet.

21. A vehicular diesel or petrol engine comprising the apparatus according to claim 13, wherein the third outlet is arranged to supply hydrogen gas to a combustion chamber of the engine.

22. An electrical generator comprising a fuel cell, preferably a vehicular electrical generator, comprising the apparatus according to claim 13, wherein the third outlet is arranged to supply hydrogen gas to the fuel cell.

23. A cooking device comprising the apparatus according to claim 13 and a burner head, wherein the third outlet is arranged to supply hydrogen gas to the burner head.

24. A welding device or a plasma cutting device comprising the apparatus according to claim 13 and a gas torch, wherein the third outlet is arranged to supply hydrogen gas to the gas torch.

25. A heating boiler comprising the apparatus according to claim 13 and a combustion chamber comprising a pilot flame, wherein the third outlet is arranged to supply hydrogen gas to the combustion chamber of the boiler.

26. A Stirling engine comprising the apparatus according to claim 13 and a heat engine, wherein the third outlet is arranged to supply hydrogen gas to the heat engine.

Description

(1) The invention will now be described in relation to the following non-limiting figures, in which:

(2) FIG. 1 shows an electrolytic cell as described herein.

(3) FIG. 2 shows an apparatus as described herein.

(4) FIG. 1 shows an electrolytic cell 1. The cell 1 comprises a tank 5 for holding ionic aqueous fluid 10, such as KOH. The system preferably uses purified water with 30% electrolyte 1M KOH standard solution to achieve the necessary conductivity for optimal performance.

(5) The cell 1 is provided with an anode 20 and a cathode 25 provided at each end of the tank 5. The cathode 25 and anode 20 are connected to an external circuit (not shown) which provides the driving force for electrolysis.

(6) The tank 5 is divided by a neutral plate 30. This results in the formation of two sub-cells. The neutral plate may have holes to allow electrolyte circulation, or the electrolyte can be piped between the sides of the neutral plate 30.

(7) The tank 5 is further divided by nylon mesh membranes 35 which are located between the neutral plate 30 and each of the anode 20 and cathode 25. This divides each of the two sub-cells so that they have a cathode-side volume 40A and an anode-side portion 40B.

(8) A magnetron 46 is provided to energise the fluid 10 in the tank 5. This reduces the electrical potential that needs to be applied by the external circuit.

(9) The tank 5 is provided with a plurality of gas outlets (45, 50). The hydrogen gas outlets 45 are provided in communication with the cathode-side volumes 40A of each sub-cell. The oxygen gas outlets 50 are provided in communication with the anode-side volumes 40B of each sub-cell.

(10) In use, a voltage is applied between the cathode 25 and the anode 20. This causes the ionic fluid 10 to decompose. Oxygen gas bubbles 55 formed at the anode 20 and on the neutral plate 30 in the anode-side volumes 40B of each sub-cell. Hydrogen gas bubbles 60 are formed at the cathode 25 and on the neutral plate 30 in the cathode-side volumes 40A of each sub-cell. Produced oxygen gas can be stored as an output for different industrial application or just released to the atmosphere.

(11) A preferred electrical circuit involves a Pulse Wave Modular working 12/24V and 0 to 140 A. Like a standard water electrolysis cell, the external circuit power provides the electrical potential to drive these reactions but with a much smaller power input.

(12) The hydrogen gas bubbles 60 are collected at the hydrogen gas outlet 45. The oxygen gas bubbles 55 are collected at the oxygen gas outlet 50. The use of a membrane 35 as described herein also serves to prevent O.sub.2 contamination in the produced H.sub.2, thus avoiding the possible explosion.

(13) Although a single neutral plate 30 is shown, typically a plurality of neutral plates 30 will be employed.

(14) FIG. 2 shows an apparatus 100 incorporating the electrolytic cell 1 described above. The above numerals have been reused as appropriate.

(15) The apparatus 100 takes hydrogen gas from the hydrogen gas outlet 45. This is passed through a flash-back inhibitor 105, past a non-return valve 110 and into a reaction chamber 115.

(16) The reaction chamber 115 takes the form of a bubbler. That is, the hydrogen gas-inlet 120 in the reaction chamber 115 is arranged to introduce the hydrogen gas towards the bottom of the reaction chamber 115. The reaction chamber 115 contains 1M KOH solution 125 and fragments of aluminium scrap waste 130.

(17) In use, the hydrogen gas bubbles through the KOH solution 125, agitating the solution 125 against the aluminium scrap waste 130. This encourages the reaction and the further production of hydrogen.

(18) The hydrogen gas leaving the reaction vessel through the outlet 135 comprises gas from the electrolysis cell and additional hydrogen gas from the reaction chamber 115.

(19) The hydrogen has leaving the reaction vessel through the outlet 135 is passed to an inlet 140 of a gas-cleaning chamber 145. The gas-cleaning chamber 145 contains water 150. The water 150 serves to capture any KOH solution 125 entrained from earlier in the apparatus.

(20) Cleaned hydrogen gas leaves the gas-cleaning chamber 145 by the outlet 155 and a control valve 160 for use. The apparatus may be coupled with a hydrogen storage device (not shown) to allow the hydrogen to be used at a controlled rate.

(21) A specific description of the structure of a suitable electrolytic cell is now provided. The layers are provided in order across the cell as follows (like terms describe identical components): 1. Acrylic plate 150×150 mm and 10 mm thickness, the plate having connections for the positive electrode, negative electrode, water input, hydrogen and oxygen output 2. Positive Plate (Inox 316 110×110 mm and 1.5 mm thickness) 3. Oxygen separator (A gasket with a connection to the Oxygen outlet) 4. Mesh Membrane (as described herein) 5. Normal Gasket 6. Hydrogen separator (A gasket with a connection to the hydrogen outlet) 7. Neutral Plate (Inox 316) 8. Oxygen separator 9. Mesh Membrane 10. Normal Gasket 11. Hydrogen separator 12. Neutral Plate 13. Oxygen separator 14. Mesh Membrane 15. Normal Gasket 16. Hydrogen separator 17. Neutral Plate 18. Oxygen separator 19. Mesh Membrane 20. Normal Gasket 21. Hydrogen separator 22. Neutral Plate 23. Oxygen separator 24. Mesh Membrane 25. Normal Gasket 26. Hydrogen separator 27. Negative Plate 28. Hydrogen separator 29. Acrylic plate 150×150 mm and 10 mm thickness

(22) Unless otherwise stated, all percentages herein are by weight and all pressures are absolute, rather than gauge.

(23) Although preferred embodiments of the invention have been described herein in detail, it will be understood by those skilled in the art that variations may be made thereto without departing from the scope of the invention or of the appended claims.