Advanced Electrolytic Storage and Recovery of Hydrogen
20220393209 · 2022-12-08
Inventors
Cpc classification
Y02E60/50
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H01M16/003
ELECTRICITY
International classification
Abstract
An apparatus for storing hydrogen as protons and electrons separately. The apparatus includes a DC power supply; a hydrogen electrolysis unit including a hydrogen tank adapted to contain hydrogen under pressure and in contact with one or more catalyst electrodes contained in the tank, the one or more catalyst electrodes in electrical connection with the DC power supply; and an electron storage unit for storing electrons, the electron storage unit in electrical connection with the DC power supply and separated from the hydrogen electrolysis unit. In a proton generation mode, the DC power supply is configured to operate the one or more catalyst electrodes in anode mode to catalyze oxidation of hydrogen in the hydrogen tank to form and store protons on or near the one or more electrodes and store generated electrons in the electron storage unit.
Claims
1. An apparatus for storing hydrogen as protons and electrons separately, the apparatus comprising: a DC power supply; a hydrogen electrolysis unit comprising a hydrogen tank adapted to contain hydrogen under pressure and in contact with one or more catalyst electrodes contained in the tank, the one or more catalyst electrodes in electrical connection with the DC power supply; an electron storage unit for storing electrons, the electron storage unit in electrical connection with the DC power supply and separated from the hydrogen electrolysis unit; wherein in a proton generation mode the DC power supply is configured to operate the one or more catalyst electrodes in anode mode to catalyze oxidation of hydrogen in the hydrogen tank to form and store protons on or near the one or more electrodes and store generated electrons in the electron storage unit.
2. The apparatus of claim 1, wherein the apparatus is also operable in a hydrogen recovery mode in which the DC power supply is configured to operate the one or more catalyst electrodes in cathode mode wherein protons on the one or more catalyst electrodes are converted to hydrogen under vacuum by recovering the electrons from the electron storage unit, under conditions to remove the hydrogen from a surface of the one or more electrodes as it is formed and remove it from the hydrogen tank.
3. The apparatus of claim 1, wherein the apparatus further comprises a humidifier configured to humidify the hydrogen with water before delivery to the hydrogen tank.
4. The apparatus of claim 1, wherein the one or more catalyst electrodes are metal impregnated electrodes wherein the metal is selected from one or more of the group consisting of platinum and platinum-iridium.
5. The apparatus of claim 1, wherein the electron storage unit is selected from one or more of the group consisting of: a capacitor, an electrolytic system, and oxygen ions contained in electrodes.
6. The apparatus of claim 5, wherein the electron storage unit is a capacitor with high surface area formed from an alloy of metals or oxide of metals.
7. The apparatus of claim 5, wherein the electron storage unit is an electrolytic system and reactions used in the chemical storage of the electrons have a low E.sub.o.
8. The apparatus of claim 5, wherein the electron storage unit is oxygen ions contained in electrodes and the process of generating hydrogen gas results in conversion of the oxygen ions to oxygen.
9. An energy storage device comprising the apparatus of claim 1.
10. A process for storing hydrogen as protons and electrons separately, the process comprising: contacting hydrogen in a tank under pressure with one or more catalyst electrodes and applying a DC power supply under conditions to operate the electrodes in anode mode and catalyze oxidation of the hydrogen at the one or more electrodes to form and store protons on or near the one or more electrodes, and storing generated electrons in a separate electron storage unit.
11. The process of claim 10, further comprising applying the DC power supply under conditions to operate the electrodes in cathode mode to convert the hydrogen protons stored on the one or more catalyst electrodes to hydrogen under vacuum by recovering the electrons from the electron storage unit, and removing the hydrogen from the surface of the electrodes as it is formed.
12. The process of claim 10, further comprising storing the protons on or near the one or more electrodes under a vacuum.
13. The process of claim 10, further comprising humidifying the hydrogen before delivery to the hydrogen tank.
14. The process of claim 10, wherein the one or more catalyst electrodes are metal impregnated electrodes wherein the metal is selected from one or more of the group consisting of platinum and platinum-iridium.
15. The process of claim 10, wherein the temperature of the electrode is maintained above 25 degrees Celsius for the recovery of the hydrogen.
16. The process of claim 10, wherein the electron storage unit is selected from one or more of the group consisting of: a capacitor, an electrolytic system, and oxygen ions contained in electrodes.
17. The process of claim 16, wherein the electron storage unit is a capacitor with very high surface area formed from an alloy of metals or oxide of metals such as carbon, rare earth metals, nickel, magnesium and/or aluminum hydrides.
18. The process of claim 16, wherein the electron storage unit is an electrolytic system and reactions used in the chemical storage of the electrons have a low E.sub.o such as the cupric-cuprous reaction that has an E.sub.o of 0.153 volts.
19. The process of claim 16, wherein the electron storage unit is oxygen ions contained in electrodes and the process of generating hydrogen gas results in conversion of the oxygen ions to oxygen.
20. The process of claim 10, wherein the proton storage and the electron storage are separate but consolidated into one vessel.
21. The apparatus of claim 6, wherein the alloy is made from carbon, rare earth metals, nickel, magnesium and/or aluminium hydrides.
22. The apparatus of claim 7, wherein the reaction used in the chemical storage of the electrons is the cupric-cuprous reaction that has an E.sub.o of 0.153 volts.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0041] Embodiments of the present invention will be discussed with reference to the accompanying drawings wherein:
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DESCRIPTION OF EMBODIMENTS
[0072] The present disclosure arises from the inventor's research on apparatus and processes that can be used to store hydrogen as protons and recover the hydrogen without the use of a liquid or gel carrier and, similarly, to store oxygen as ions and then recover the oxygen. It is notable that 2 grams of hydrogen has a volume of 22.4 litres at standard temperature and pressure while 2 grams of hydrogen protons have a volume of 5.0585×10.sup.−18 litres. For oxygen, 32 grams of oxygen has a volume of 22.4 litres at standard temperature and pressure. The calculated volume of 1 kilogram of oxygen ions is 0.315625 litres. The volume of 1 kilogram of liquid oxygen is 1.141 litres. Hydrogen has an energy density of 142 mega-joules per kilogram while a lithium ion battery has an energy density of 0.3 to 0.8 mega-joules per kilogram. As shown in
[0073] The present inventor undertook extensive research to determine how to store hydrogen successfully as a proton without the use of a liquid or gel carrier. The inventor has extensive experience in hydrogen fuel cell electrodes in the early 1900s and is aware that the method of deployment of the platinum catalyst is crucial to the success of the catalysis of the electron removal. In initial research, electrically deposited platinum coated titanium mesh electrodes were not successful for storing hydrogen protons. Further research was carried out where the electrodes were replaced with fuel cell type electrodes. However, catalysis of the hydrogen could not be achieved.
[0074] Following this research, the inventor determined that to store the hydrogen successfully as a proton, electrons removed from the protons needed to be stored in another vessel. These electrons can then be recovered and delivered to the protons when required.
[0075] Thus, provided herein is an apparatus 10 for storing hydrogen as protons and electrons separately. As used herein, the term “storing hydrogen as protons and electrons separately”, or similar terms, means that the protons and electrons are electronically isolated from one another during storage. The apparatus comprises a DC power supply 12, a hydrogen electrolysis unit 14 and an electron storage unit 16.
[0076] The hydrogen electrolysis unit comprises a hydrogen tank 18 adapted to contain hydrogen under pressure and in contact with one or more catalyst electrodes 20 contained in the tank. The one or more catalyst electrodes 20 are in electrical connection with the DC power supply 12.
[0077] The electron storage unit 16 is used for storing electrons and it is in electrical connection with the DC power supply 12 and is separated from the hydrogen electrolysis unit 14.
[0078] The apparatus 10 can be operated in a proton generation mode in which the DC power supply 12 is configured to operate the one or more catalyst electrodes 20 in anode mode to catalyze oxidation of pressurized hydrogen in the hydrogen tank 18 at the one or more catalyst electrodes 20 to form and store protons on or near the one or more electrodes in the hydrogen tank and store generated electrons in the electron storage unit 16.
[0079] In addition, the apparatus 10 can be operated in a hydrogen recovery mode in which the DC power supply 12 is configured to operate the one or more catalyst electrodes 20 in cathode mode wherein hydrogen protons on the one or more electrodes are converted to hydrogen under vacuum by recovering the electrons from the electron storage unit 16 and adding these to the hydrogen protons, under conditions to remove the hydrogen from a surface of the one or more electrodes 20 as it is formed and remove it from the hydrogen tank 18.
[0080] Apparatus according to embodiments of the present disclosure are shown schematically in
[0081] Electrons can be stored in the electron storage unit 16 in any one or more of the following ways: [0082] Electrons can be stored in a capacitor, [0083] Electrons can be stored chemically, and/or [0084] Electrons can be stored in oxygen ions.
[0085] In some embodiments, the apparatus 10 includes a humidifier for the humidifying the hydrogen. Any commercially available humidifier can be used. Typically, the hydrogen can be humidified by contacting a hydrogen stream with water such that some of the water is transferred to the hydrogen stream. The hydrogen may be humidified to from about 10% to about 100% humidity, such as about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 100%. Depending on the composition of the catalyst electrodes and the temperature in the hydrogen tank, humidifying the hydrogen may assist in the proton formation step. Humidification may not be required if highly efficient catalysts or higher temperatures are used.
[0086] An embodiment of the apparatus is shown in
[0087] For the apparatus shown schematically in
[0088] In the apparatus shown in
[0089] In all experiments, the circuit is closed as shown in
TABLE-US-00001 TABLE 1 Proton Accumulation with Dry H.sub.2 Anode, Dry H.sub.2 Cathode and Closed Circuit I.sub.DC V.sub.DC (A) (V) 0.000 0.00 0.020 3.00 0.034 5.00 0.066 10.00 0.088 15.00 0.112 20.00
[0090] With dry hydrogen the current, which indicates the amount of hydrogen converted to protons, is very small. At 5 volts, the current was only 0.034 amperes.
[0091] Table 2 shows the significant increase in hydrogen being converted to protons when the hydrogen is humidified.
TABLE-US-00002 TABLE 2 Proton Accumulation with Humidified H.sub.2 Anode Humidified H.sub.2 Cathode Duration I.sub.DC V.sub.DC I.sub.CAP V.sub.CAP (hh:mm) (A) (V) (A) (V) 0:00 0.000 0.00 0.0 0.0003 0:02 5.000 1.71 5.0 0.0135 0:05 5.000 1.42 5.0 0.0204 0:10 5.000 1.55 5.0 0.0338 0:15 5.000 1.62 5.0 0.0467 0:20 5.000 1.68 5.0 0.0586 0:30 5.000 1.78 5.0 0.0843 0:40 5.000 1.88 5.0 0.1101 0:50 5.000 1.98 5.0 0.1355 1:00 5.000 2.09 5.0 0.1598 1:10 5.000 2.21 5.0 0.1841 1:20 5.000 2.35 5.0 0.2082 1:30 5.000 2.51 5.0 0.2345 2:10 5.000 5.91 5.0 0.3312
[0092] V.sub.DC is the voltage at the DC supply and V.sub.cap is the voltage from the capacitor. The current was limited to 5 amperes as this was the maximum allowed by the H-60 Fuel Cell. The voltage steadily increased from 0 to 5.91 after 2 hours and 10 minutes as the capacitor was loaded with electrons at a voltage of 0.3312 volts. The temperature of the humidifier was 30 degrees C. Increasing this temperature did not increase the current, a measure of the protonisation of the hydrogen.
[0093] This shows that hydrogen protonation increased substantially when the hydrogen in contact with the fuel cell electrodes was humidified.
[0094] The H-60 fuel cell was subjected to vacuum and then the current was reversed to deliver the electrons from the capacitors to the anode of the H-60 fuel cell. The difficulty was measuring the small amount of hydrogen produced which was too low to activate the hydrogen flow sensor. The solution was to add a constant flow of nitrogen to the hydrogen. Specifically, nitrogen at 1 litre per minute was fed to the hydrogen meter after the vacuum pump discharge. Nitrogen at 1 litre per minute was also fed to the box around the H-60 fuel cell. The gas inlet and outlet of the cathode were sealed and the gas outlet of the anode was sealed and the inlet of the anode was connected to the vacuum pump.
[0095] The hydrogen from the H-60 fuel cell was detected as shown in Table 3 when the temperature of the H-60 fuel Cell reached 51.2 degrees C. Most likely, there was less energy required at 51.2 degrees C. to allow the production of hydrogen from the protons.
TABLE-US-00003 TABLE 3 Production of Hydrogen from H-60 Fuel Cell Stack Normalised Current Hydrogen Evolution Temperature (° C.) through stack (A/V.sub.cell) (mol.Math.s.sup.−1) 25.4 0.045 0 35.6 0.045 0 51.2 0.058 6.69 10.sup.−8
[0096] Preferably, the anode electrode containing the hydrogen protons is enclosed so that high vacuum can be applied to the recovery of hydrogen. An example of a suitable hydrogen tank is shown in
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[0098] A construction of a suitable electrode 20 is shown in
[0099] The construction of the capacitor is shown in
[0100] On the platinum coated anode electrodes, the hydrogen under pressure is oxidized to form electrons and protons as occurs in PEM Fuel Cells. The protons remain on the surface of the anode and the electrons are taken to the positive of the DC supply and the negative delivers the electrons to the capacitor. The capacitor consists of a bank of 4×50 capacitors.
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[0103] Results of experiments conducted using the apparatus shown in
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[0105] In an alternative method for storing electrons shown in
[0106] The storage and recovery of hydrogen protons and oxygen ions with a carrier was discussed in international patent application WO 2016/134401 A1. In this invention, the storage of hydrogen as a proton and oxygen as an ion is carried out without a carrier. This is very appropriate because in the electrolysis of water, hydrogen and oxygen are produced. Normally, it is convenient to release the oxygen to the atmosphere and then recover it later in the fuel cell operation; however, in some applications such as hydrogen submarines and rocket type airplanes, it is necessary to carry oxygen as fuel.
[0107] Detailed apparatus for production of protons and storage of electrons in oxygen is shown in
[0108] Aside from the applications of this invention mentioned in international patent application WO 2016/134401, the following are examples of the commercial applications of the dry storage of hydrogen.
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[0110] A major application of the apparatus of the present disclosure is in providing low cost reliable energy storage to cyclic renewable energy such as wind or solar (
[0111] Current aircraft are major carbon polluters because the carbon dioxide, unburnt hydrocarbons and nitrous oxide are delivered high in the atmosphere where the effect on climate change is at a maximum. The apparatus of the present disclosure can be applied to low speed aircraft using propellers or up to rocket type aircrafts as shown in
[0112] The apparatus of the present disclosure can also be applied to submarines and ships which will be cheaper and safer than nuclear powered submarines and warships (
[0113] Throughout the specification and the claims that follow, unless the context requires otherwise, the words “comprise” and “include” and variations such as “comprising” and “including” will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.
[0114] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge.
[0115] It will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular application described. Neither is the present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the invention is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention as set forth and defined by the following claims.