CN116988087B - Diaphragm-free electrolytic tank, system and operation method for hydrogen production from wastewater - Google Patents
Diaphragm-free electrolytic tank, system and operation method for hydrogen production from wastewater Download PDFInfo
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- CN116988087B CN116988087B CN202311265640.0A CN202311265640A CN116988087B CN 116988087 B CN116988087 B CN 116988087B CN 202311265640 A CN202311265640 A CN 202311265640A CN 116988087 B CN116988087 B CN 116988087B
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- 239000001257 hydrogen Substances 0.000 title claims abstract description 189
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 189
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 184
- 239000002351 wastewater Substances 0.000 title claims abstract description 158
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 68
- 238000000034 method Methods 0.000 title claims description 56
- 238000000576 coating method Methods 0.000 claims abstract description 138
- 239000011248 coating agent Substances 0.000 claims abstract description 137
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 104
- 239000000956 alloy Substances 0.000 claims abstract description 104
- 239000000758 substrate Substances 0.000 claims abstract description 58
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 10
- HTXDPTMKBJXEOW-UHFFFAOYSA-N dioxoiridium Chemical compound O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910000457 iridium oxide Inorganic materials 0.000 claims abstract description 8
- 229910001925 ruthenium oxide Inorganic materials 0.000 claims abstract description 8
- WOCIAKWEIIZHES-UHFFFAOYSA-N ruthenium(iv) oxide Chemical compound O=[Ru]=O WOCIAKWEIIZHES-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052751 metal Inorganic materials 0.000 claims description 92
- 239000002184 metal Substances 0.000 claims description 91
- 239000007788 liquid Substances 0.000 claims description 87
- 239000007789 gas Substances 0.000 claims description 66
- 239000003792 electrolyte Substances 0.000 claims description 53
- 238000000926 separation method Methods 0.000 claims description 50
- 238000003860 storage Methods 0.000 claims description 44
- 238000000746 purification Methods 0.000 claims description 41
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 claims description 40
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 37
- 238000001755 magnetron sputter deposition Methods 0.000 claims description 30
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 29
- 239000011159 matrix material Substances 0.000 claims description 27
- 239000000203 mixture Substances 0.000 claims description 26
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 claims description 25
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 24
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 24
- 239000002910 solid waste Substances 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 230000001105 regulatory effect Effects 0.000 claims description 16
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 10
- 239000007787 solid Substances 0.000 claims description 10
- 238000004140 cleaning Methods 0.000 claims description 9
- 229910052750 molybdenum Inorganic materials 0.000 claims description 9
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- 238000010849 ion bombardment Methods 0.000 claims description 8
- 238000002360 preparation method Methods 0.000 claims description 8
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims description 4
- 239000000292 calcium oxide Substances 0.000 claims description 4
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 4
- 239000000945 filler Substances 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 abstract description 29
- 229910052760 oxygen Inorganic materials 0.000 abstract description 29
- 229910052759 nickel Inorganic materials 0.000 abstract description 22
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 21
- 238000004065 wastewater treatment Methods 0.000 abstract description 20
- 239000012528 membrane Substances 0.000 abstract description 11
- 238000004880 explosion Methods 0.000 abstract description 10
- 229910052717 sulfur Inorganic materials 0.000 abstract description 9
- 229910052726 zirconium Inorganic materials 0.000 abstract description 6
- 229910052782 aluminium Inorganic materials 0.000 abstract description 5
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 abstract description 3
- 238000002156 mixing Methods 0.000 abstract description 3
- 239000010936 titanium Substances 0.000 abstract description 3
- 229910052719 titanium Inorganic materials 0.000 abstract description 3
- 238000011017 operating method Methods 0.000 abstract 1
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 114
- 238000004544 sputter deposition Methods 0.000 description 63
- 238000005868 electrolysis reaction Methods 0.000 description 49
- 239000011651 chromium Substances 0.000 description 43
- 239000010964 304L stainless steel Substances 0.000 description 34
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 24
- 230000000052 comparative effect Effects 0.000 description 24
- 238000005265 energy consumption Methods 0.000 description 16
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 14
- 239000000243 solution Substances 0.000 description 14
- 229910052786 argon Inorganic materials 0.000 description 12
- 239000000460 chlorine Substances 0.000 description 12
- 229910052801 chlorine Inorganic materials 0.000 description 12
- 230000003197 catalytic effect Effects 0.000 description 11
- 239000006260 foam Substances 0.000 description 11
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 10
- 238000005238 degreasing Methods 0.000 description 10
- 238000012360 testing method Methods 0.000 description 10
- 239000011247 coating layer Substances 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 8
- 239000007921 spray Substances 0.000 description 8
- 238000005260 corrosion Methods 0.000 description 7
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- 229910052757 nitrogen Inorganic materials 0.000 description 6
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- 244000137852 Petrea volubilis Species 0.000 description 5
- 229910002092 carbon dioxide Inorganic materials 0.000 description 5
- 239000001569 carbon dioxide Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 150000002431 hydrogen Chemical class 0.000 description 5
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- 239000013505 freshwater Substances 0.000 description 4
- 239000011810 insulating material Substances 0.000 description 4
- FBMUYWXYWIZLNE-UHFFFAOYSA-N nickel phosphide Chemical compound [Ni]=P#[Ni] FBMUYWXYWIZLNE-UHFFFAOYSA-N 0.000 description 4
- 238000005477 sputtering target Methods 0.000 description 4
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- 238000012544 monitoring process Methods 0.000 description 3
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- 229910000619 316 stainless steel Inorganic materials 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 2
- 239000004155 Chlorine dioxide Substances 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- OSVXSBDYLRYLIG-UHFFFAOYSA-N chlorine dioxide Inorganic materials O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 description 2
- 238000010288 cold spraying Methods 0.000 description 2
- 239000010840 domestic wastewater Substances 0.000 description 2
- QWPPOHNGKGFGJK-UHFFFAOYSA-N hypochlorous acid Chemical compound ClO QWPPOHNGKGFGJK-UHFFFAOYSA-N 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
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- 238000002791 soaking Methods 0.000 description 2
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910000599 Cr alloy Inorganic materials 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910018487 Ni—Cr Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
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- 230000008021 deposition Effects 0.000 description 1
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- 238000005516 engineering process Methods 0.000 description 1
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- 239000005431 greenhouse gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
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- 239000007769 metal material Substances 0.000 description 1
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- 238000006467 substitution reaction Methods 0.000 description 1
- WWNBZGLDODTKEM-UHFFFAOYSA-N sulfanylidenenickel Chemical compound [Ni]=S WWNBZGLDODTKEM-UHFFFAOYSA-N 0.000 description 1
- 238000005486 sulfidation Methods 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
- C25B9/70—Assemblies comprising two or more cells
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/46104—Devices therefor; Their operating or servicing
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/02—Hydrogen or oxygen
- C25B1/04—Hydrogen or oxygen by electrolysis of water
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/34—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B15/00—Operating or servicing cells
- C25B15/02—Process control or regulation
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B15/00—Operating or servicing cells
- C25B15/02—Process control or regulation
- C25B15/023—Measuring, analysing or testing during electrolytic production
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B15/00—Operating or servicing cells
- C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes
- C25B15/083—Separating products
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
- C25B9/60—Constructional parts of cells
-
- Y—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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Automation & Control Theory (AREA)
- Inorganic Chemistry (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
Abstract
The invention relates to a diaphragm-free electrolytic tank, a diaphragm-free electrolytic system and a diaphragm-free operating method for producing hydrogen from wastewater, belonging to the technical field of wastewater treatment and electrolytic hydrogen production. The diaphragm-free electrolytic cell comprises N electrolytic cells connected in series, wherein each electrolytic cell comprises a cathode and an anode; the cathode comprises a Ni-based high-entropy alloy coating formed on a substrate, wherein the Ni-based high-entropy alloy coating contains Ni and Al, and further contains more than three elements selected from Zr, ti, cr, mo, co, ce, P, S, the Ni-based high-entropy alloy coating contains 5-35 atomic percent of Ni, 0.2-10 atomic percent of Al and 0.3-35 atomic percent of other elements; the anode includes an iridium oxide or ruthenium oxide or titanium suboxide coating formed on a substrate. The invention can efficiently produce hydrogen and efficiently treat wastewater, flexibly and dynamically regulate the working power range of the electrolytic cell, solve the problems of weak fluctuation resistance of the membrane electrolytic cell and the like, and effectively avoid the risk of explosion caused by mixing oxygen and hydrogen.
Description
Technical Field
The invention belongs to the technical field of wastewater treatment and electrolytic hydrogen production, and particularly relates to a diaphragm-free electrolytic tank, a diaphragm-free electrolytic system and a diaphragm-free operation method for wastewater hydrogen production.
Background
The hydrogen is used as an energy carrier with high heat value, three times of heat of the gasoline with the same quality can be released in the combustion process, and the hydrogen can not generate greenhouse gas carbon dioxide after being combusted, and the hydrogen can become one of main energy storage substances in the future under the background of double carbon.
The most dominant source of hydrogen is electrolytic water to produce hydrogen, with megawatt hydrogen production technologies mostly employing Alkaline Electrolysers (AEL) and proton exchange membrane electrolysers (PEM). However, AEL and PEM cells suffer from high cost, membrane poisoning, complex assembly, and the like. Especially, the commercial membrane electrolytic cell has the problems of weak fluctuation resistance and large ohmic resistance, and can not be directly connected with renewable energy sources such as solar energy, wind energy, geothermal energy and the like. More importantly, most commercial electrolytic tanks adopt fresh water for hydrogen production, and in the process of continuously expanding hydrogen production scale, the fresh water hydrogen production increases the hydrogen production cost and causes global fresh water resource shortage. Under the background, the adoption of the membraneless electrolytic tank for producing hydrogen from the wastewater not only reduces the demand for fresh water resources, but also realizes the treatment of the wastewater while producing hydrogen by electrolysis, simplifies the wastewater treatment process flow and cost, and provides more possibilities for the wastewater treatment process. However, the safety problem of hydrogen-oxygen mixing in the diaphragm-free electrolytic cell adopted at present is still widely concerned.
Chinese patent CN202211193301.1 discloses an integrated system for wastewater treatment and electrolytic hydrogen production and an operation method thereof, but the electrolytic tank in the patent still adopts a membrane electrolytic tank, which has one or more problems of high cost, large ohmic resistance, complex assembly, weak fluctuation resistance, complex wastewater treatment process, higher hydrogen production energy consumption, explosion risk when oxygen and hydrogen are mixed, and the like, and further strengthening is needed in terms of simplifying wastewater treatment flow and improving hydrogen and oxygen purity.
In summary, there is a great need for a diaphragm-free electrolyzer, system and method of operation for wastewater hydrogen production.
Disclosure of Invention
The invention provides a diaphragm-free electrolytic cell, a diaphragm-free electrolytic system and an operation method for producing hydrogen from waste water, which aim to solve one or more technical problems of high cost, high ohmic resistance, complex assembly, weak fluctuation resistance, complex waste water treatment process, high hydrogen production energy consumption, explosion risk when oxygen and hydrogen are mixed in the prior art. The invention can efficiently produce hydrogen, efficiently treat wastewater, reduce the process flow of wastewater treatment, flexibly and dynamically regulate and control the working power range of the electrolytic cell, overcome the problems of high cost, weak fluctuation resistance and the like of the membrane electrolytic cell, and effectively avoid the explosion risk of oxygen and hydrogen mixing.
The present invention provides in a first aspect a diaphragm-free electrolyzer for hydrogen production from waste water, the diaphragm-free electrolyzer comprising N electrolysis cells connected in series, each electrolysis cell comprising a cathode and an anode; the cathode includes a metal substrate and a Ni-based high-entropy alloy coating formed on the metal substrate; the Ni-based high-entropy alloy coating contains Ni and Al and also contains more than three elements selected from Zr, ti, cr, mo, co, ce, P, S; the atomic percentage of Ni in the Ni-based high-entropy alloy coating is 5-35%, the atomic percentage of Al is 0.2-10%, and the atomic percentage of other elements is 0.3-35%; the anode includes a metal substrate and an iridium oxide coating or ruthenium oxide coating or titanium oxide coating formed on the metal substrate.
The present invention provides in a second aspect a system for wastewater hydrogen production, the system for wastewater hydrogen production comprising: the device comprises a wastewater tank, a flow sensor, a diaphragm-free electrolytic tank, a gas purification system and a separation system which are connected in sequence; the diaphragm-free electrolytic cell is the diaphragm-free electrolytic cell according to the first aspect of the invention; the external power supply is used for providing electrolytic energy for the diaphragm-free electrolytic tank; a storage system comprising a hydrogen storage system, a liquid oxygen storage system, and a hypochlorite storage tank; the control system is respectively connected with the flow sensor, the external power supply, the diaphragm-free electrolytic tank, the gas purification system, the separation system and the hydrogen storage system.
The present invention provides in a third aspect a method of operating the system for hydrogen production from wastewater of the present invention described in the second aspect, the method of operating comprising the steps of:
s1, acquiring a preset working condition parameter range of a system for producing hydrogen from wastewater by the control system according to wastewater flow, COD content, chloride ion content, ammonia nitrogen content and an external power supply power fluctuation range;
s2, after the control system receives the working condition information of the flow sensor, the diaphragm-free electrolytic cell, the gas purification system, the separation system and the hydrogen storage system, the working condition information is integrated and then the operating power of the diaphragm-free electrolytic cell is dynamically regulated and controlled, so that the working condition information is regulated to be within the working condition parameter range; in step S2, the operation power of the diaphragm-free electrolytic cell is regulated and controlled by regulating the number of the electrolytic cells operated in the diaphragm-free electrolytic cell.
Compared with the prior art, the invention has at least the following beneficial effects:
(1) The diaphragm-free electrolytic cell has low requirement on water quality, does not need a complicated high-energy-consumption purification process, can be directly used for producing hydrogen by waste water electrolysis and realizing waste water treatment, and is used for producing hydrogen by electrolysis while treating ammonia nitrogen and COD in waste water; the diaphragm-free electrolytic tank has no membrane component or no gas separator in the electrolytic tank, so that the electrode plates can be tightly connected, the volume of the electrolytic tank is effectively reduced, and the production process of the electrolytic tank is simplified.
(2) The diaphragm-free electrolytic tank comprises a cathode plate and an anode plate at two ends and a plurality of bipolar plates, wherein the cathode is a Ni-based high-entropy alloy coating formed on a metal matrix, the anode is an iridium oxide or ruthenium oxide or titanium dioxide coating formed on the metal matrix, the cathode and the anode have good corrosion resistance and catalytic performance, the cathode can realize high-efficiency degradation of COD and ammonia nitrogen by the anode and realize high-efficiency hydrogen production by the cathode, the process flow of wastewater treatment is reduced, and hypochlorite with a disinfection effect can be obtained.
(3) The diaphragm-free electrolytic cell is formed by connecting a plurality of electrolytic cells in series, can flexibly regulate and control the working power range of the electrolytic cell, can be directly connected with any renewable energy source, and solves the problem of weak fluctuation resistance of the membrane electrolytic cell; the minimum power of the diaphragm-free electrolytic cell is not limited by the explosion limit of hydrogen-oxygen mixture, has better fluctuation resistance compared with a membrane electrolytic cell, and has lower manufacturing cost compared with AEL and PEM electrolytic cells; the diaphragm-free electrolytic cell has high power input flexibility, high power efficiency and low water quality requirement, and can be used for efficiently degrading COD and ammonia nitrogen in electrolytic wastewater and simultaneously co-producing hydrogen.
(4) The system for producing hydrogen from the waste water realizes waste water treatment while producing hydrogen from the waste water, is an integrated system of waste water treatment and electrolytic hydrogen production, and is preferably used for producing hydrogen from the waste water, and comprises a waste water tank, a flow sensor, a diaphragm-free electrolytic tank, a gas purification system, a separation system, a storage system, an external power supply, a PLC (programmable logic controller) control system, a solid waste collection system, a heat exchanger and the like.
(5) The separation system can obtain liquid oxygen with purity more than 99.9% and hydrogen with purity more than 99.99%, wherein the liquid oxygen has higher medical value, the hydrogen is preferably reinjected (returned) to the gas-liquid collecting device at the top of the diaphragm-free electrolytic cell after partial heat exchange, the oxygen proportion in the whole loop is reduced, the risk of hydrogen-oxygen mixed explosion at any point in the system is effectively avoided, and partial hydrogen is reinjected to the gas-liquid collecting device at the top of the diaphragm-free electrolytic cell after heat exchange, so that the heat utilization rate is also effectively improved.
Drawings
The drawings of the present invention are provided for illustrative purposes only and the proportion, the size, and the number of the parts in the drawings do not necessarily coincide with the actual products.
FIG. 1 is a schematic three-dimensional structure of a diaphragm-free electrolyzer for hydrogen production from wastewater in accordance with some embodiments of the invention;
FIG. 2 is a schematic two-dimensional structure of a diaphragm-free electrolyzer for wastewater hydrogen production in some embodiments of the invention;
FIG. 3 is a schematic diagram of a system for producing hydrogen from wastewater in accordance with some embodiments of the invention.
In the figure, 1: a wastewater tank; 2: a flow sensor; 3: a diaphragm-free electrolytic cell; 31: a gas-liquid collecting device; 311: a gas-liquid mixture outlet; 32: an anode plate; 33: a cathode plate; 34: a bipolar plate; 341: a flow gap; 35: an electrolyte inlet; 36: an electrolyte outlet; 37: a bolt; 4: a gas purification system; 5: a separation system; 6: a hydrogen storage system; 7: a liquid oxygen storage system; 8: a hypochlorite storage tank; 9: a control system; 10: a solid waste collection system; 11: an external power supply; 12: a heat exchanger; 13: a settling tank; 14: a water pump; 15: a flow control valve.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below in connection with the embodiments of the present invention. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The present invention provides in a first aspect a diaphragm-free electrolyzer for hydrogen production from waste water, the diaphragm-free electrolyzer comprising N electrolysis cells connected in series, each electrolysis cell comprising a cathode and an anode; the cathode includes a metal substrate and a Ni-based high-entropy alloy coating formed on the metal substrate; the Ni-based high-entropy alloy coating comprises Ni (nickel) and Al (aluminum), and further comprises more than three elements selected from Zr (zirconium), ti (titanium), cr (chromium), mo (molybdenum), co (cobalt), ce (cerium), P (phosphorus) and S (sulfur); the atomic percentage of Ni in the Ni-based high-entropy alloy coating is 5-35%, the atomic percentage of Al is 0.2-10%, and the atomic percentage of other elements is 0.3-35%; in the invention, the sum of the atomic percentages of the elements in the Ni-based high-entropy alloy coating is 100%; the anode includes a metal substrate and an iridium oxide coating or ruthenium oxide coating or titanium oxide coating formed on the metal substrate.
The cathode adopted by the diaphragm-free electrolytic tank is composed of a metal matrix and a Ni-based high-entropy alloy coating, wherein the metal matrix is preferably foamed nickel with good hydrogen evolution performance or stainless steel with good corrosion resistance, the Ni-based high-entropy alloy coating is prepared from five or six or more elements of Ni-Zr-Ti-Cr-Mo-Co-Ce-Al-P-S, and specifically, the Ni-based high-entropy alloy coating contains Ni and Al and also contains more than three elements selected from Zr, ti, cr, mo, co, ce, P, S; the cathode has high catalytic performance, good mechanical property and excellent corrosion resistance, so that the cathode can be used for a long time under severe wastewater conditions; the anode adopted by the diaphragm-free electrolytic tank is composed of a metal matrix and an iridium oxide coating or a ruthenium oxide coating or a titanium dioxide coating formed on the metal matrix, and the cathode and the anode have good corrosion resistance and catalytic performance, so that the cathode can realize high-efficiency degradation of COD and ammonia nitrogen and realize high-efficiency hydrogen production in cooperation with the cathode, the process flow of wastewater treatment is reduced, and hypochlorite with a disinfection effect is obtained.
The diaphragm-free electrolytic cell has low requirement on water quality, does not need a complicated high-energy-consumption purification process, can be directly used for producing hydrogen by waste water electrolysis and realizing waste water treatment, and is used for producing hydrogen by electrolysis while treating ammonia nitrogen and COD in waste water; the diaphragm-free electrolytic tank has no membrane component or no gas separator in the electrolytic tank, so that the electrode plates can be tightly connected, the volume of the electrolytic tank is effectively reduced, and the production process of the electrolytic tank is simplified; the diaphragm-free electrolytic cell is formed by connecting a plurality of electrolytic cells in series, can flexibly regulate and control the working power range of the electrolytic cell, can be directly connected with any renewable energy source, overcomes the problem of weak fluctuation resistance of the membrane electrolytic cell, and has lower manufacturing cost than AEL and PEM electrolytic cells.
In the present invention, the diaphragm-free electrolytic cell for wastewater hydrogen production can be used for various wastewater hydrogen production, including but not limited to chlorine-containing wastewater, which can be, for example, one or more of chlorine-containing oilfield wastewater, industrial wastewater (e.g., food industrial wastewater or industrial COD wastewater), medical wastewater, and domestic wastewater; in the invention, the electrolytic hydrogen production of chlorine-containing wastewater is taken as an example, so that the wastewater treatment flow can be simplified, and the risk of hydrogen-oxygen mixed explosion in a diaphragm-free electrolytic tank can be reduced, and the concrete principle is as follows: when the chlorine-containing wastewater is electrolyzed, chlorine separation (CER) reaction is firstly carried out on the anode, chlorine is dissolved in electrolyte and reacts with water to form hypochlorous acid with an oxidation effect, the hypochlorous acid further degrades COD in the electrolyte (such as oil field wastewater or industrial wastewater) into carbon dioxide, and chloride ions are generated (the chloride ions can be electrolyzed into chlorine again at the anode, and the chloride ions are basically not lost in the electrolysis process); in this process, the anode may compete for Oxygen Evolution (OER) reactions and the cathode co-produces hydrogen; preferably, part of the hydrogen generated by the cathode is reinjected to the diaphragm-free electrolytic cell after being purified, so that the oxygen generated by the anode does not reach the explosion limit of hydrogen-oxygen mixture, and the commercial application of the diaphragm-free electrolytic cell is feasible.
According to some preferred embodiments, N.gtoreq.2, N being a positive integer.
According to some preferred embodiments, for example, as shown in fig. 1 and 2, the diaphragm-free electrolytic tank 3 includes a cathode plate 33 and an anode plate 32 at both ends, and a plurality of bipolar plates 34 for dividing the diaphragm-free electrolytic tank 3 into N electrolytic cells, the cathode plate 33 being a cathode, the anode plate 32 being an anode, a side of the bipolar plates 34 adjacent to the cathode plate 33 being an anode, and a side of the bipolar plates 34 adjacent to the anode plate 32 being a cathode; in the present invention, it is preferable that the distance between two adjacent bipolar plates 34 is 10 to 50mm; in the invention, a bipolar plate 34 is arranged between every two electrolysis cells, the substrate of the bipolar plate 34 is a metal substrate, one surface (cathode surface) of the metal substrate is a Ni-based high-entropy alloy coating and is used as a cathode, and the other surface (anode surface) of the metal substrate is an iridium oxide coating or a ruthenium oxide coating or a titanium oxide coating and is used as an anode; in the invention, when the coating on the bipolar plate is prepared, the coating on the cathode surface is prepared first, and then the coating on the anode surface is prepared; in the present invention, the bipolar plate is located in the middle of the diaphragm-free electrolytic cell; in the present invention, it is preferable that the Ni-based high-entropy alloy coating of the cathode face of the bipolar plate has the same composition as the Ni-based high-entropy alloy coating on the cathode plate, and the coating of the anode face of the bipolar plate has the same composition as the coating on the anode plate; in the invention, the cathode of each electrolysis cell comprises a metal matrix and the Ni-based high-entropy alloy coating, so that the cathode has better catalytic performance and corrosion resistance under the condition of wastewater.
According to some preferred embodiments, the cathode plate 33 and the anode plate 32 are connected with an external power supply in an on-off way, and the bipolar plate 34 is also connected with the external power supply in an on-off way, so as to realize flexible adjustment of the working load of the diaphragm-free electrolytic cell, in particular, the cathode plate and the anode plate are respectively connected with the negative pole and the positive pole of the external power supply in an on-off way; the bipolar plate can also be connected with the external power supply in an on-off mode to form a cathode or an anode of the diaphragm-free electrolytic cell, so that the work load of the diaphragm-free electrolytic cell can be flexibly adjusted; in the present invention, the term "on-off connectable" means that the cathode plate and the anode plate can be selectively electrically connected to or disconnected from an external power source, and the bipolar plate can also be selectively electrically connected to or disconnected from the external power source; in the invention, the number of the bipolar plates can be increased or reduced at will, each electrolysis cell can work independently, the bipolar plates can also be directly connected with an external power supply to form a cathode or an anode of the diaphragm-free electrolysis cell, so that the work load of the electrolysis cell can be flexibly adjusted; for example, the external power supply is solar energy, when the electric quantity input is large in the daytime, the cathode plate can be connected to the cathode of the power supply through the control system, and all the electrolysis cells in the diaphragm-free electrolysis cell are in a working state at the moment; when the electric quantity is input in the night and the night, the second bipolar plate can be connected to the negative electrode of the power supply through the control system, only two electrolysis cells in the diaphragm-free electrolysis cell are in a working state, and the flexible adjustment of the work load of the electrolysis cell can be applied to various renewable energy sources, so that the utilization rate of the power supply is improved.
In some specific embodiments, the bipolar plate 34, the cathode plate 33 and the anode plate 32 may be connected by bolts 37, for example, preferably, the bolts are insulating bolts, and in the present invention, the insulating bolts are bolts made of insulating materials; the specific structure of the diaphragm-free electrolytic tank 3 is shown in fig. 1 and 2, for example, the diaphragm-free electrolytic tank 3 comprises an anode plate 32 and a cathode plate 33 which are positioned at the left end and the right end, and bipolar plates 34 which are used for dividing the diaphragm-free electrolytic tank 3 into N electrolytic cells, wherein the number of the bipolar plates is N-1, and N is more than or equal to 2; a cylindrical structure (not shown) is arranged among the cathode plate 33, the anode plate 32 and the bipolar plate 34, the anode plate, the bipolar plate and the cathode plate are positioned at the axial end parts of the cylindrical structure, namely in the invention, a cylindrical structure is arranged between the anode plate and the bipolar plate, a cylindrical structure is arranged between the bipolar plate and the cathode plate, when N is more than or equal to 3, a cylindrical structure is arranged between every two bipolar plates, and the anode plate, the bipolar plate and the cathode plate are positioned at the axial end parts of the cylindrical structure; in the present invention, it is preferable that a circulation gap 341 is formed at an upper portion or a lower portion of the bipolar plate 34, the circulation gaps 341 formed at two adjacent bipolar plates are alternately disposed up and down, and the circulation gap 341 is used for allowing the electrolyte entering the non-diaphragm electrolytic cell to flow into each of the electrolytic cells connected in series in sequence; specifically, in the invention, the inside of the cylinder structure is hollow, the anode plate, the bipolar plate and the anode plate are tightly compressed into a whole with each cylinder structure, and electrolyte passes through the circulation gaps formed in the inside of the cylinder structure and the upper and lower parts of the bipolar plate; in the invention, the anode plate, the cathode plate and the bipolar plate can be collectively called as polar plates, each two polar plates and one cylindrical structure form an electrolysis cell, and one cylindrical structure corresponds to one electrolysis cell, namely the electrolysis cell is formed by the cylindrical structure and the anode plate, the cathode plate or the bipolar plate positioned at the end part of the cylindrical structure; the cylinder structure is made of insulating materials, the insulating materials are not particularly limited, and the insulating materials conventionally adopted by the electrolytic tank are adopted; bolt holes for bolts 37 to pass through are formed in the peripheries of the cathode plate 33, the anode plate 32, the bipolar plate 34 and the cylindrical structure, and the bipolar plate, the cathode plate and the anode plate can be connected in series through bolts; the bipolar plate, cathode plate and/or anode plate may be circular, for example; in the present invention, the cylindrical structure may be, for example, an insulating gasket, and the cylindrical structure protects the separator plate from deformation during long-term use, and it is specifically noted that the specific structure of the diaphragm-free electrolytic cell is only an example, and other structures that can connect the electrolytic cells in series are possible, and are not to be construed as limiting the scope of the present invention.
According to some preferred embodiments, for example, as shown in fig. 1 and 2, an electrolyte inlet 35 is provided at one end of the anode plate 32 of the non-diaphragm electrolytic tank 3, an electrolyte outlet 36 is provided at one end of the cathode plate 33 of the non-diaphragm electrolytic tank 3, the electrolyte entering from the electrolyte inlet 35 is waste water, and the electrolyte flowing from the electrolyte outlet 36 is a solution containing hypochlorite.
According to some specific embodiments, an electrolyte inlet is arranged at one end of an anode plate of the diaphragm-free electrolytic tank, an electrolyte outlet is arranged at one end of a cathode plate of the diaphragm-free electrolytic tank, electrolyte entering from the electrolyte inlet is waste water, electrolyte flowing out from the electrolyte outlet is a solution containing hypochlorite, preferably, the electrolyte inlet is arranged at the lower part of the anode plate, electrolyte flows into a first electrolysis cell from the electrolyte inlet at the lower part of the anode plate, flows into a second electrolysis cell from a circulation gap at the upper part of a first bipolar plate after flowing through the first electrolysis cell, flows into a third electrolysis cell from a circulation gap at the lower part of a second bipolar plate after flowing through the second electrolysis cell, and flows out from the electrolyte outlet at one side of the cathode plate until the electrolyte flows out from all the electrolysis cells, the electrolyte outlet can be arranged at the upper part or the lower part of the cathode plate, the electrolyte flowing out from the electrolyte outlet is a solution containing hypochlorite with a disinfection effect, and the electrolyte outlet can be connected with a hypochlorite storage tank.
According to some preferred embodiments, the diaphragm-free electrolyzer is used for the simultaneous electrolysis hydrogen production of ammonia nitrogen and COD in wastewater; preferably, after wastewater enters a diaphragm-free electrolytic tank, chlorine evolution reaction is firstly carried out on an anode, micro oxygen evolution reaction is carried out in competition, and then electrolyte continues to flow until COD in the electrolyte is degraded to an externally-discharged standard; the cathodes of all the electrolysis cells are subjected to hydrogen evolution reaction.
According to some preferred embodiments, the top of the diaphragm-free electrolytic tank 3 is provided with a gas-liquid collecting device 31 for collecting a gas-liquid mixture generated by hydrogen production from wastewater, the diaphragm-free electrolytic tank 3 is sequentially connected with a gas purification system and a separation system through the gas-liquid collecting device 31, the gas-liquid mixture flows out of the gas-liquid collecting device and then sequentially passes through the gas purification system and the separation system to obtain hydrogen and liquid oxygen, and part of the obtained hydrogen is returned to the gas-liquid collecting device after heat exchange, so that the hydrogen ratio in the gas-liquid collecting device can be increased, the hydrogen ratio is the volume ratio (volume concentration ratio) of the hydrogen to the hydrogen-oxygen mixture, the oxygen ratio in the whole loop can be reduced, and the risk of hydrogen-oxygen mixed explosion can be effectively avoided; in the present invention, the gas-liquid collecting device communicates with each electrolysis cell, and for example, a cylindrical structure which may be an electrolysis cell communicates with the gas-liquid collecting device; in the present invention, the gas-liquid mixture may include, for example, hydrogen, oxygen, chlorine, carbon dioxide, and/or an electrolyte; in the invention, one side of the gas-liquid collecting device, which is positioned at the top end of the cathode plate, is a cathode side, and one side of the gas-liquid collecting device, which is positioned at the top end of the anode plate, is an anode side; preferably, the gas-liquid mixture flows out from the cathode side of the gas-liquid collecting device and then sequentially passes through a gas purifying system and a separating system to obtain high-purity hydrogen and liquid oxygen (liquid oxygen), and part of the obtained hydrogen enters the gas-liquid collecting device again from the anode side of the gas-liquid collecting device after heat exchange (for example, heat exchange by a heat exchanger), more preferably, 10-30% of the obtained hydrogen enters the gas-liquid collecting device again from the anode side of the gas-liquid collecting device after heat exchange; specifically, in the present invention, a hydrogen inlet is disposed on the anode side of the gas-liquid collecting device 31, a gas-liquid mixture outlet 311 is disposed on the cathode side of the gas-liquid collecting device 31, and the gas-liquid mixture flows out from the gas-liquid mixture outlet 311 and then sequentially passes through a gas purification system and a separation system to obtain high-purity hydrogen and liquid oxygen (liquid oxygen), and part of the obtained hydrogen enters the gas-liquid collecting device again through the hydrogen inlet of the gas-liquid collecting device after heat exchange.
According to some preferred embodiments, the Ni-based high-entropy alloy coating has the following general formula: ni (Ni) x A y B z Al w Wherein A is one or more of Zr, ti and Cr, and B is at least two of Mo, co, ce, P, S; x, y, z, w are all atomic percentages, x is more than or equal to 5% and less than or equal to 35%, y is more than or equal to 5% and less than or equal to 35%, z is more than or equal to 10% and less than or equal to 10%, w is more than or equal to 0.2% and less than or equal to 10%, and x+y+z+w=100%; in the invention, the Ni-based high-entropy alloy coating is based on Ni element, preferably one or more of passivation elements Zr, ti and Cr are added, so that the surface passivation capability of the cathode for hydrogen production by electrolysis of wastewater is improved, the cathode has long-term stability in wastewater, preferably at least two (such as two or three) of synergistic elements Mo, co, ce, P, S are added, the catalytic activity of a cathode electrode is further improved, and meanwhile, al element is added, so that the cathode can be used for adjusting the crystal structure of the high-entropy alloy, and the cathode is also beneficial to dealloying to form a porous nano structure; in some more preferred embodiments, the addition of synergistic elements P and/or S may cause partial sulfidation or phosphating of the high-entropy alloy, which is beneficial to promote hydrogen evolution properties of the high-entropy alloy. The Ni-based high-entropy alloy coating can effectively improve the intrinsic catalytic activity by utilizing the synergistic effect among alloy elements, and adjust the structure of a catalytic interface to increase the number of catalytic active sites; meanwhile, the synergistic effect among alloy elements can also improve the corrosion resistance of the metal material.
According to some preferred embodiments, A is Cr, B is Mo and Co,30% or less x.ltoreq.35% (x may for example take the value 30%, 31%, 32%, 33%, 34% or 35%), 5% or less y.ltoreq.15% (y may for example take the value 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%), in the Ni-based high entropy alloy coating, the atomic percentage of Mo is 25-35% (for example 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34% or 35%), the atomic percentage of Co is 20-32% (for example 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31% or 32%).
According to some preferred embodiments, A is Cr, B is Mo, ce and P, or B is Mo, ce and S,30% x.ltoreq.35% (x may take on values of 30%, 31%, 32%, 33%, 34% or 35%, for example) 5% y.ltoreq.15% (y may take on values of 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, for example) in which the atomic percentage of Mo is 25-35% (e.g. 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34% or 35%), the atomic percentage of Ce is 20-32% (e.g. 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31% or 32%), the atomic percentage of P or S is 0.3-2% (e.g. 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.1.4%, 1.1.1%, 1.7% or 1.1% or 2%).
In the invention, x is preferably more than or equal to 30% and less than or equal to 35%, y is preferably more than or equal to 5% and less than or equal to 15%, and w is preferably more than or equal to 0.2% and less than or equal to 10%, and the invention discovers that if the value of x is too low and the value of y is too high, the hydrogen evolution catalytic performance of the cathode is obviously reduced; in the present invention, it is further preferable that the ratio of the atomic percent of Mo to the atomic percent of Co is (0.8 to 1.8): 1 (e.g., 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, or 1.8:1), or the atomic percent ratio of Mo to atomic percent of Ce is (0.8-1.8): 1 (e.g., 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, or 1.8:1), which is advantageous in ensuring that the cathode is more excellent in hydrogen evolution catalytic performance.
The process of forming the iridium oxide coating, ruthenium oxide coating, or titanium oxide coating is not particularly limited, and may be prepared by a cold spray process, for example, and is a conventional technique in the art.
According to some preferred embodiments, the Ni-based high-entropy alloy coating is prepared by a magnetron sputtering method; preferably, the magnetron sputtering is magnetron sputtering co-sputtering.
According to some preferred embodiments, the Ni-based high-entropy alloy coating is a porous Ni-based high-entropy alloy coating prepared by: firstly preparing a Ni-based high-entropy alloy coating on the surface of a metal matrix by a magnetron sputtering method, and then performing dealloying treatment on the Ni-based high-entropy alloy coating formed on the metal matrix to obtain the porous Ni-based high-entropy alloy coating.
According to some preferred embodiments, the process parameters of the magnetron sputtering are: background vacuum is not greater than 5×10 - 4 Pa, the process air pressure is 0.4-0.7 Pa, magnetron sputtering is carried out by using a direct current power supply, the power of the direct current power supply is 40-140W (for example, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130 or 140W), and the magnetron sputtering time is 30-100 min (for example, 30, 40, 50, 60, 70, 80, 90 or 100 min); preferably, before the Ni-based high-entropy alloy coating is prepared on the surface of the metal matrix by a magnetron sputtering method, ion bombardment glow cleaning is carried out on the target; preferably, in the present invention, when P or S is not contained in the Ni-based high-entropy alloy coating layer, the temperature of the magnetron sputtering is room temperature, for example, 15 to 35 ℃ room temperature; when the Ni-based high-entropy alloy coating contains P and/or S elements, the temperature of the magnetron sputtering is 180-200 ℃; in the invention, when P is contained in the Ni-based high-entropy alloy coating, a sputtering target material NiP (nickel phosphide) is adopted, and when S is contained in the Ni-based high-entropy alloy coating, a sputtering target material NiS (nickel sulfide) is adopted; when each metal element is contained in the Ni-based high-entropy alloy coating, the sputtering target is a pure metal target of a single element corresponding to the metal component, namely the sputtering target is a simple substance metal target corresponding to each metal element; of course, for the metallic elements Ni and Cr, an alloy target may be used.
According to some preferred embodiments, the dealloying treatment is: placing the Ni-based high-entropy alloy coating formed on the surface of the metal substrate in a sodium hydroxide solution with the concentration of 0.05-0.15 mol/L for soaking treatment for 1-3 h; preferably, the Ni-based high-entropy alloy coating formed on the surface of the metal substrate is placed in a sodium hydroxide solution (sodium hydroxide aqueous solution) with a concentration of 0.1mol/L for soaking treatment for 2 hours; in the present invention, the metal substrate and the Ni-based high-entropy alloy coating formed on the surface of the metal substrate are integrally immersed in a sodium hydroxide solution to perform dealloying treatment.
According to some preferred embodiments, the Ni-based high-entropy alloy coating has a thickness of 0.6-8 μm (e.g. 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7 or 8 μm); and/or in the cathode and the anode, the metal matrix is nickel or stainless steel, preferably, the nickel is nickel plate, nickel mesh or foam nickel, and the stainless steel is 304L stainless steel, 316 stainless steel or 316L stainless steel. In the invention, the main purpose of selecting the foam nickel as the metal matrix is to further improve the hydrogen evolution catalytic performance of the cathode, the main purpose of selecting the stainless steel as the metal matrix is to further improve the corrosion resistance of the cathode electrode in the wastewater, and the foam nickel and the stainless steel are both good conductors, thereby being beneficial to the magnetron sputtering deposition of the Ni-based high-entropy alloy coating; preferably, the thickness of the metal substrate is 1 to 3mm, more preferably 2mm.
The present invention provides in a second aspect a system for producing hydrogen from wastewater, for example, as shown in fig. 3, in which the system for producing hydrogen from wastewater is an integrated system for wastewater treatment and electrolysis hydrogen production, the system for producing hydrogen from wastewater comprising:
the device comprises a wastewater tank 1, a flow sensor 2, a diaphragm-free electrolytic tank 3, a gas purification system 4 and a separation system 5 which are connected in sequence; the diaphragm-free electrolytic tank 3 is the diaphragm-free electrolytic tank according to the first aspect of the invention; the flow sensor 2 is connected to the passages of the wastewater tank 1 and the diaphragm-free electrolytic tank 3 and is used for monitoring the flow of wastewater entering the diaphragm-free electrolytic tank 3; the gas purification system is connected to, for example, the top end of a cathode plate (cathode side) of a diaphragm-free electrolytic cell for removing water, chlorine and/or carbon dioxide from a gas-liquid mixture; the separation system 5 is connected with the gas purification system 4 for separating hydrogen and oxygen; an external power supply 11, wherein the external power supply 11 is used for providing electrolytic energy for the diaphragm-free electrolytic tank 3; a storage system comprising a hydrogen storage system 6, a liquid oxygen storage system 7 and a hypochlorite storage tank 8; the control system 9 is respectively connected with the flow sensor 2, the external power supply 11, the diaphragm-free electrolytic tank 3, the gas purification system 4, the separation system 5 and the hydrogen storage system 6; in the present invention, the control system 9 is, for example, a PLC control system.
According to some preferred embodiments, the system for hydrogen production from wastewater further comprises a water pump 14 for delivering wastewater in the wastewater tank 1, the water pump 14 being arranged in the path of the flow sensor 2 connected to the wastewater tank 1, preferably the water pump 14 being connected to the control system 9; the system for producing hydrogen from wastewater also comprises a solid waste collection system 10, wherein the solid waste collection system 10 is used for collecting solid waste in the wastewater tank 1 and/or solid waste in the diaphragm-free electrolytic tank 3; the solid waste collection system 10 is connected with the wastewater tank 1; the system for hydrogen production from waste water further comprises a settling tank 13 for solid-liquid separation, wherein the inlet of the settling tank 13 is connected with the diaphragm-free electrolytic tank 3, specifically, for example, is connected with an electrolyte outlet 36 of the diaphragm-free electrolytic tank 3, and the outlet of the settling tank 13 is respectively connected with a solid waste collection system 10 and a hypochlorite storage tank 8; specifically, the settling tank 13 has two outlets, a solid outlet and a liquid outlet, respectively, the solid outlet being connected to the solid waste collection system 10 and the liquid outlet being connected to the hypochlorite storage tank 8; and/or the hydrogen storage system 6 and the liquid oxygen storage system 7 are connected to the separation system 5.
According to some preferred embodiments, the gas purification system 4 comprises a filler, which is solid calcium oxide and/or solid sodium hydroxide.
According to some preferred embodiments, a heat exchanger 12 is arranged between the gas purification system 4 and the separation system 5, preferably the heat exchanger 12 is connected to the control system 9; in the invention, the gas flowing out of the gas purification system 4 is generally normal temperature (for example, about 15-35 ℃), the separation system 5 condenses by adopting liquid nitrogen, the temperature of the flowing out hydrogen is about-200 ℃, and the two gases with different temperatures exchange heat in the heat exchanger 12, so that the temperature of the gas flowing out of the gas purification system is reduced (which is equivalent to precooling, and the consumption of energy in the separation system is reduced), and part of cold energy of low-temperature hydrogen discharged from the separation system is recovered.
According to some preferred embodiments, a gas-liquid collecting device 31 for collecting a gas-liquid mixture generated by hydrogen production from wastewater is arranged at the top of the non-diaphragm electrolytic tank 3, the non-diaphragm electrolytic tank 3 is sequentially connected with the gas purification system 4 and the separation system 5 through the gas-liquid collecting device 31, the gas-liquid mixture flows out of the gas-liquid collecting device 31 and sequentially passes through the gas purification system 4 and the separation system 5 to obtain hydrogen and liquid oxygen, the obtained partial hydrogen is returned to the gas-liquid collecting device 31 after heat exchange by the heat exchanger 12, for example, the gas-liquid mixture flows out of the cathode side of the gas-liquid collecting device 31 and sequentially passes through the gas purification system 4 and the separation system 5 to obtain hydrogen and liquid oxygen, and the obtained partial hydrogen enters the gas-liquid collecting device 31 again from the anode side of the gas-liquid collecting device 31 after heat exchange by the heat exchanger 12; preferably, the obtained 10-30% hydrogen enters the gas-liquid collecting device 31 again from the anode side of the gas-liquid collecting device 31 after heat exchange by the heat exchanger 12; in the present invention, it is preferable that the system for producing hydrogen from wastewater further comprises a gas pump (not shown in the drawing) for delivering part of the hydrogen obtained from the separation system 5, which is provided on a path in which the heat exchanger 12 is connected to the gas-liquid collecting device 31 of the diaphragm-free electrolyzer 3, and in the present invention, it is preferable that the gas pump is also connected to the control system 9; in the present invention, preferably, a flow control valve 15 is disposed on a path of hydrogen returning to the gas-liquid collecting device 31, for example, as shown in fig. 3, a part of the obtained hydrogen passes through the flow control valve 15 and then enters the heat exchanger 12 to exchange heat, the control system 9 is connected with the flow control valve 15, the flow control valve is controlled by the control system so as to control the amount of the hydrogen entering the heat exchanger to exchange heat, for example, the control system controls the flow control valve so that 10-30% of the obtained hydrogen enters the gas-liquid collecting device 31 again from the anode side of the gas-liquid collecting device 31 after exchanging heat by the heat exchanger; preferably, the gas-liquid collecting device of the diaphragm-free electrolytic tank is also connected with the control system, an oxygen sensor is arranged in the gas-liquid collecting device, when the oxygen sensor in the gas-liquid collecting device detects that the oxygen content is about to exceed the explosion limit, the control system is used for conveying the hydrogen after heat exchange into the gas-liquid collecting device, the hydrogen-oxygen ratio in the gas-liquid collecting device is dynamically regulated, the conveying hydrogen ratio is at most not more than 30%, and when the conveying of 30% of hydrogen still does not reach the safety range, the maintenance is stopped immediately.
According to some specific embodiments, the system for producing hydrogen from wastewater comprises: the device comprises a wastewater tank 1, a water delivery pump 14, a flow sensor 2, a diaphragm-free electrolytic tank 3, a gas purification system 4, a separation system 5, a storage system (comprising a hydrogen storage system 6, a liquid oxygen storage system 7 and a hypochlorite storage tank 8), an external power supply 11, a PLC control system, a heat exchanger 12, a settling tank 13 and a solid waste collection system 10, wherein the inlet of the settling tank 13 is connected with the diaphragm-free electrolytic tank 3, and the outlet of the settling tank 13 is respectively connected with the solid waste collection system 10 and the hypochlorite storage tank 8; in the present invention, the wastewater tank is used for storing primarily treated wastewater, including but not limited to chlorine-containing wastewater (e.g., chlorine-containing oilfield wastewater), food industry wastewater, medical wastewater, and/or domestic wastewater; the flow sensor is connected to the passages of the wastewater tank and the diaphragm-free electrolytic tank and used for monitoring the flow of wastewater entering the diaphragm-free electrolytic tank and further transmitting the flow working condition to the PLC control system; the gas purification system is connected with a gas-liquid collecting device at the top of the diaphragm-free electrolytic tank and is used for removing water, chlorine and/or carbon dioxide in the gas-liquid mixture, and preferably, solid calcium oxide and/or solid sodium hydroxide are arranged in the gas purification system and can be reused after being dried; the separation system is connected with the gas purification system and is used for separating hydrogen and oxygen, the purity of the hydrogen and the liquid oxygen after low-temperature separation is more than 99.9%, and the liquid oxygen can be directly used as medical oxygen; the external power supply is connected with the diaphragm-free electrolytic tank and used for providing electrolytic energy, and the electrolytic energy can be wind energy, solar energy, water energy, geothermal energy and the like; the control system is respectively connected with the flow sensor, the diaphragm-free electrolytic cell, the gas purification system, the separation system and the hydrogen storage system, and is mainly used for receiving power supply information and operation condition information and dynamically adjusting the operation power of the diaphragm-free electrolytic cell; the heat exchanger carries out heat exchange treatment on the gas flowing out of the gas purification system and the reinjected low-temperature hydrogen, so that the heat utilization rate is improved.
According to some preferred embodiments, the electrolyte of each electrolysis cell in the diaphragm-free electrolyzer comes from the preceding electrolysis cell (the electrolyte of the first electrolysis cell comes from the wastewater basin), the anode of each electrolysis cell undergoes a different catalytic reaction; after wastewater enters a diaphragm-free electrolytic tank, chlorine evolution reaction is carried out on an anode, micro oxygen evolution reaction is carried out in competition, and then electrolyte continues to flow until COD in the electrolyte is degraded to an externally-discharged standard; the cathodes of all the electrolysis cells are subjected to hydrogen evolution reaction.
According to some preferred embodiments, the separation system 5 is used for separating mixed hydrogen and oxygen, and after the gas-liquid mixture generated in the diaphragm-free electrolytic tank 3 is collected by the gas-liquid collecting device 31, the gas-liquid mixture enters the gas purification system 4 to be dried and decontaminated, and then enters the separation system 5; the separation system 5 is operated in a liquid nitrogen circulation atmosphere at a temperature of 75K, and thus can also be referred to as a cryogenic separation system, in which case oxygen is condensed to liquid oxygen having a purity of greater than 99.9% (the boiling point of oxygen is 90K), the purity of hydrogen exiting the separation system 5 is greater than 99.9%, and a portion of the hydrogen is returned to the gas-liquid collection device.
The present invention provides in a third aspect a method of operating the system for hydrogen production from wastewater of the present invention described in the second aspect, the method of operating comprising the steps of:
S1, acquiring a preset working condition parameter range of a system for producing hydrogen from wastewater by the control system according to wastewater flow, COD content, chloride ion content, ammonia nitrogen content and an external power supply power fluctuation range;
s2, after the control system receives the working condition information of the flow sensor, the diaphragm-free electrolytic cell, the gas purification system, the separation system and the hydrogen storage system, the working condition information is integrated and then the operating power of the diaphragm-free electrolytic cell is dynamically regulated and controlled, so that the working condition information is regulated to be within the working condition parameter range; in the step S2, the operation power of the non-diaphragm electrolytic tank is regulated and controlled by regulating the number of the electrolysis cells operated in the non-diaphragm electrolytic tank, namely, the operation power of the non-diaphragm electrolytic tank is regulated and controlled by regulating the number of the electrolysis cells operated in the non-diaphragm electrolytic tank; in the invention, for example, in the process of operating the wastewater treatment and electrolytic hydrogen production of the system for producing hydrogen from wastewater, the control system can dynamically regulate and control according to the wastewater flow of a wastewater tank, the COD content in wastewater, the chloride ion content, the ammonia nitrogen content, the power of a diaphragm-free electrolytic cell, the pollution reducing capacity of the diaphragm-free electrolytic cell (the rated reduction of the total amount of COD and ammonia nitrogen per kilowatt of energy), the treated water flow of the diaphragm-free electrolytic cell, the rated electrolytic water amount of the diaphragm-free electrolytic cell per kilowatt of energy, the solid wastewater flow, the solution flow containing hypochlorite, the gas flow of a gas purification system, the gas flow of a separation system, the flow of a heat exchanger, the hydrogen flow and the power supply power of a gas-liquid collecting device which flows into the diaphragm-free electrolytic cell again, and the control can be selected by a person skilled in the art according to actual needs.
According to some preferred embodiments, when the control system receives the power fluctuation information of the external power supply, the operation power of the diaphragm-free electrolytic cell is dynamically regulated after the power fluctuation information and the actual working condition information are integrated; in the present invention, the cause of the fluctuation in electric power is instability of renewable energy sources including one or more of wind energy, solar energy, water energy and geothermal energy.
The invention will be further illustrated by way of example, but the scope of the invention is not limited to these examples.
Example 1
The present embodiment provides a system for producing hydrogen from wastewater, as shown in fig. 3, the system for producing hydrogen from wastewater comprising: the device comprises a wastewater tank, a flow sensor, a diaphragm-free electrolytic tank, a gas purification system and a separation system which are connected in sequence; the external power supply is used for providing electrolytic energy for the diaphragm-free electrolytic tank, and the electrolytic energy is solar energy; a storage system comprising a hydrogen storage system, a liquid oxygen storage system, and a hypochlorite storage tank; the PLC control system is respectively connected with the flow sensor, the external power supply, the diaphragm-free electrolytic cell, the gas purification system, the separation system and the hydrogen storage system; the system for producing hydrogen from the wastewater also comprises a water delivery pump for delivering the wastewater in the wastewater tank, wherein the water delivery pump is arranged on a passage connected with the wastewater tank by the flow sensor, and the water delivery pump is connected with a PLC control system; the system for producing hydrogen from wastewater also comprises a solid waste collecting system, wherein the solid waste collecting system is used for collecting solid waste in a wastewater tank and solid waste in the diaphragm-free electrolytic tank, the system for producing hydrogen from wastewater also comprises a settling tank for solid-liquid separation, an inlet of the settling tank is connected with the diaphragm-free electrolytic tank, and an outlet of the settling tank is respectively connected with the solid waste collecting system and a hypochlorite storage tank; the hydrogen storage system and the liquid oxygen storage system are connected with the separation system; the gas purification system is filled with solid calcium oxide; the separation system operates in a liquid nitrogen circulation atmosphere at a temperature of 75K; a heat exchanger is arranged between the gas purification system and the separation system, and the heat exchanger is connected with the control system; the top of the diaphragm-free electrolytic tank is provided with a gas-liquid collecting device for collecting a gas-liquid mixture generated by hydrogen production from wastewater, the diaphragm-free electrolytic tank is sequentially connected with the gas purification system and the separation system through the gas-liquid collecting device, the gas-liquid mixture flows out of the gas-liquid collecting device and sequentially passes through the gas purification system and the separation system to obtain hydrogen and liquid oxygen, the obtained partial hydrogen is returned to the gas-liquid collecting device after heat exchange by a heat exchanger, a flow control valve is arranged on a passage of the hydrogen returning to the gas-liquid collecting device, the obtained partial hydrogen firstly passes through the flow control valve and then enters the heat exchanger for heat exchange, the PLC control system is connected with the flow control valve, and the PLC control system controls the flow control valve so as to control the quantity of the hydrogen entering the heat exchanger for heat exchange; the system for producing hydrogen from the wastewater further comprises a gas transmission pump for transmitting part of hydrogen obtained from the separation system, wherein the gas transmission pump is arranged on a passage of the heat exchanger connected with a gas-liquid collecting device of the diaphragm-free electrolytic tank, and the gas transmission pump is connected with a PLC control system.
In the embodiment, the wastewater tank is used for storing oilfield wastewater, and the oilfield wastewater is used as electrolyte, wherein the flow rate of the oilfield wastewater is 900L/h, the chloride ion content is 12000mg/L, the COD content is 2000mg/L, and the ammonia nitrogen content is 340mg/L; the flow sensor is connected to the passages of the wastewater tank and the diaphragm-free electrolytic tank and used for monitoring the flow of wastewater entering the diaphragm-free electrolytic tank and further transmitting the flow working condition to the PLC control system; the diaphragm-free electrolytic tank comprises N (10) electrolytic cells connected in series, the diaphragm-free electrolytic tank comprises a cathode plate and an anode plate which are positioned at two ends, and 9 bipolar plates used for dividing the diaphragm-free electrolytic tank into 10 electrolytic cells, and the distance between every two adjacent bipolar plates is 40mm; the cathode plate is a cathode, the anode plate is an anode, one surface of the bipolar plate, which is close to the cathode plate, is an anode, and one surface of the bipolar plate, which is close to the anode plate, is a cathode; the negative plate and the positive plate are respectively connected with the negative electrode and the positive electrode of an external power supply in an on-off mode; the bipolar plate can also be connected with the external power supply in an on-off mode to form a cathode or an anode of the diaphragm-free electrolytic cell, so that the work load of the diaphragm-free electrolytic cell can be flexibly adjusted; one end of an anode plate of the diaphragm-free electrolytic tank is provided with an electrolyte inlet, one end of a cathode plate of the diaphragm-free electrolytic tank is provided with an electrolyte outlet, electrolyte entering from the electrolyte inlet is the oilfield wastewater, and electrolyte flowing from the electrolyte outlet is a solution containing hypochlorite; in this embodiment, the structure of the diaphragm-free electrolytic cell is as shown in fig. 1 or 2, for example; in this embodiment, in the process of producing hydrogen from waste water, the PLC control system dynamically regulates and controls the number of electrolysis cells in the non-diaphragm electrolytic tank according to the working condition information, the anode of the external power supply is connected with the anode plate of the non-diaphragm electrolytic tank, the cathode of the external power supply is connected with the 5 th bipolar plate, in this embodiment, the non-diaphragm electrolytic tank uses 5 electrolysis cells altogether, and 15% of hydrogen flowing out of the separation system enters the gas-liquid collection device again after heat exchange of the heat exchanger through the PLC control system.
In the diaphragm-free electrolytic cell of the present embodiment, the cathode plate includes a metal base (304L stainless steel substrate having a thickness of 2 mm) and a Ni-based high-entropy alloy coating (Ni having a thickness of 2 μm) formed on the metal base 0.35 Cr 0.08 Mo 0.30 Co 0.20 Al 0.07 A high entropy alloy coating); the anode plate comprises a metal base (304L stainless steel substrate with the thickness of 2 mm) and a titanium oxide coating with the thickness of 2 μm formed on the metal base, each of the bipolar plates comprises a metal base (304L stainless steel substrate with the thickness of 2 mm), a Ni-based high-entropy alloy coating (Ni with the thickness of 2 μm) formed on one side (cathode side) of the metal base 0.35 Cr 0.08 Mo 0.30 Co 0.20 Al 0.07 High entropy alloy coating) and a titanium oxide coating layer having a thickness of 2 μm formed on the other surface (anode surface) of the metal base.
In the present embodiment, ni on the cathode plate 0.35 Cr 0.08 Mo 0.30 Co 0.20 Al 0.07 High entropy alloy coating and Ni on the cathode face of the bipolar plate 0.35 Cr 0.08 Mo 0.30 Co 0.20 Al 0.07 The high-entropy alloy coating is prepared by a magnetron co-sputtering method, and the preparation method comprises the following steps: firstly polishing 304L stainless steel (serving as a metal matrix of magnetron sputtering) with the thickness of 2mm by using sand paper, and then carrying out degreasing pretreatment; ni targets, cr targets, mo targets, co targets and Al targets with the purity of 99.99 percent are adopted as sputtering cathodes; vacuumizing to 5×10 -4 Under Pa, high-purity argon is introduced to adjust the required negative pressure to 0.5Pa, and then pre-sputtering is carried out for 10min at room temperature of 25 ℃ so as to carry out ion bombardment glow cleaning on each target; continuously introducing high-purity argon as process gas, keeping the process air pressure in the vacuum chamber at 0.5Pa, adjusting the sputtering power of the Ni target at 75W, the sputtering power of the Cr target at 85W, the sputtering power of the Mo target at 74W, the sputtering power of the Co target at 57W, the sputtering power of the Al target at 68W, and forming a sputtering angle of a sputtering gun at 90 degrees (namely 90 degrees) with the horizontal direction, wherein the magnetron sputtering is performed at the room temperature of 25 ℃Shooting for 40min; ni with thickness of 2 μm is obtained on a 304L stainless steel substrate after degreasing pretreatment 0.35 Cr 0.08 Mo 0.30 Co 0.20 Al 0.07 High entropy alloy coating.
In this embodiment, the titanium oxide coating on the anode plate and the titanium oxide coating on the anode surface of the bipolar plate are both prepared by a cold spray process, and the preparation method comprises: pretreating (cleaning and sand blasting roughening treatment) 304L stainless steel (metal matrix) with the thickness of 2 mm; loading titanium dioxide powder into a powder feeder of cold spraying equipment, fixing the pretreated 304L stainless steel substrate on a spraying clamp, setting cold spraying technological parameters, setting working gas as nitrogen, setting the temperature of the working gas to 450 ℃, setting the pressure of the working gas to 2.0MPa, setting the distance between the outlet of a spray gun and the surface of the 304L stainless steel substrate to be 35mm, and obtaining a titanium dioxide coating with the thickness of 2 mu m on the surface of the 304L stainless steel substrate.
The system for wastewater hydrogen production in this example was at 600mA/cm 2 After 10min of operation at the current density of the non-diaphragm electrolyzer, taking the electrolyzed wastewater (namely the solution containing hypochlorite) at the electrolyte outlet of the non-diaphragm electrolyzer for testing; the COD content in the electrolyzed wastewater is measured to be 52mg/L, the ammonia nitrogen content is measured to be 29mg/L, and the hydrogen production energy consumption is measured to be 4.56kWh/kgH 2 。
Example 2
Example 2 is substantially the same as example 1 except that:
in the diaphragm-free electrolytic cell of the present embodiment, the cathode plate includes a metal base (foam nickel substrate having a thickness of 2 mm) and a Ni-based high-entropy alloy coating having a thickness of 5 μm formed on the foam nickel substrate; the anode plate comprises a metal matrix (a foam nickel substrate with the thickness of 2 mm) and a titanium suboxide coating with the thickness of 2 mu m formed on the metal matrix; each of the bipolar plates includes a metal base (foam nickel substrate having a thickness of 2 mm), a Ni-based high-entropy alloy coating having a thickness of 5 μm formed on one side (cathode side) of the metal base, and a titanium oxide coating having a thickness of 2 μm formed on the other side (anode side) of the metal base.
In this embodiment, the Ni-based high-entropy alloy coating on the cathode plate and the Ni-based high-entropy alloy coating on the cathode surface on the bipolar plate are Ni formed on the surface of the metal substrate by magnetron co-sputtering 0.30 Cr 0.10 Mo 0.31 Co 0.22 Al 0.07 The high-entropy alloy coating is obtained through dealloying treatment; the preparation method of the magnetron co-sputtering comprises the following steps: carrying out oil removal pretreatment on foam nickel with the thickness of 2mm (serving as a metal matrix of magnetron sputtering); ni targets, cr targets, mo targets, co targets and Al targets with the purity of 99.99 percent are adopted as sputtering cathodes; vacuumizing to 5×10 -4 Under Pa, high-purity argon is introduced to adjust the required negative pressure to 0.5Pa, and then pre-sputtering is carried out for 10min at room temperature of 25 ℃ so as to carry out ion bombardment glow cleaning on each target; continuously introducing high-purity argon as process gas, keeping the process air pressure in the vacuum chamber at 0.5Pa, adjusting the sputtering power of the Ni target to 70W, the sputtering power of the Cr target to 84W, the sputtering power of the Mo target to 82W, the sputtering power of the Co target to 52W, the sputtering power of the Al target to 68W, and performing magnetron sputtering at room temperature of 25 ℃ for 100min, wherein the sputtering angle of the sputtering gun is 90 degrees with the horizontal direction; ni with thickness of 5 μm is obtained on a foam nickel substrate 0.30 Cr 0.10 Mo 0.31 Co 0.22 Al 0.07 A high entropy alloy coating; then the Ni formed on the foam nickel substrate 0.30 Cr 0.10 Mo 0.31 Co 0.22 Al 0.07 The high-entropy alloy coating is soaked in 0.1mol/L NaOH aqueous solution for 2 hours to carry out dealloying treatment, and the Ni-based high-entropy alloy coating with the nano-pore structure is obtained on the foam nickel substrate.
In this example, the titanium oxide coating on the anode plate and the titanium oxide coating on the anode face of the bipolar plate were prepared using the same cold spray process as in example 1.
The system for wastewater hydrogen production in this example was at 600mA/cm 2 After 10min of operation under the current density of the non-diaphragm electrolytic tank, taking the electrolyzed wastewater at the electrolyte outlet of the non-diaphragm electrolytic tank for testing; the COD content in the electrolyzed wastewater is measured to be 62 mg/L, the ammonia nitrogen is measured to be 34 mg/L, and the energy consumption for hydrogen production is measured to be 4.23kWh/kgH 2 。
Example 3
Example 3 is substantially the same as example 1 except that:
in the embodiment, the anode of the external power supply is connected with the anode plate of the non-diaphragm electrolytic cell through the PLC control system, the cathode of the external power supply is connected with the 8 th bipolar plate to form the cathode of the non-diaphragm electrolytic cell, and in the embodiment, 8 electrolytic cells are used in total in the non-diaphragm electrolytic cell.
The system for wastewater hydrogen production in this example was at 600mA/cm 2 After 10min of operation under the current density of the non-diaphragm electrolytic tank, taking the electrolyzed wastewater at the electrolyte outlet of the non-diaphragm electrolytic tank for testing; the COD content in the waste water after electrolysis is measured to be 31mg/L, the ammonia nitrogen content is measured to be 13mg/L, and the energy consumption for hydrogen production is measured to be 4.84kWh/kgH 2 The method comprises the steps of carrying out a first treatment on the surface of the In the operation process of the embodiment, the number of the electrolysis cells flowing through is large, the degradation effect is good, but the energy consumption can be slightly increased.
Example 4
Example 4 is substantially the same as example 1 except that:
in the embodiment, the flow rate of the oilfield wastewater is 1600L/h, the chloride ion content is 20000mg/L, the COD content is 1800mg/L, and the ammonia nitrogen content is 400mg/L.
The system for wastewater hydrogen production in this example was at 600mA/cm 2 After 10min of operation under the current density of the non-diaphragm electrolytic tank, taking the electrolyzed wastewater at the electrolyte outlet of the non-diaphragm electrolytic tank for testing; the COD content in the waste water after electrolysis is 194mg/L, the ammonia nitrogen content is 75mg/L, and the energy consumption for hydrogen production is 4.41kWh/kgH 2 The method comprises the steps of carrying out a first treatment on the surface of the In the operation process of the embodiment, the wastewater treatment flow is larger, the oilfield wastewater flow is more than 1.7 times that of the embodiment 1, but the degradation and removal efficiency of COD and ammonia nitrogen is only slightly reduced, and the hydrogen production energy consumption can be kept very low, which shows that the system for producing hydrogen by using wastewater in the invention is also suitable for large-flow wastewater treatment and electrolytic hydrogen production.
Example 5
Example 5 is substantially the same as example 1 except that:
in the diaphragm-less electrolytic cell of the present embodiment,the cathode plate comprises a metal base (304L stainless steel substrate with the thickness of 2 mm) and a Ni-based high-entropy alloy coating (Ni with the thickness of 2 μm) 0.33 Cr 0.08 Mo 0.2 8 Ce 0.22 Al 0.07 P 0.02 A high entropy alloy coating); the anode plate comprises a metal base (304L stainless steel substrate with the thickness of 2 mm) and a titanium oxide coating with the thickness of 2 μm formed on the metal base, each of the bipolar plates comprises a metal base (304L stainless steel substrate with the thickness of 2 mm), a Ni-based high-entropy alloy coating (Ni with the thickness of 2 μm) formed on one side (cathode side) of the metal base 0.33 Cr 0.08 Mo 0.28 Ce 0.22 Al 0.07 P 0.02 High entropy alloy coating) and a titanium oxide coating layer having a thickness of 2 μm formed on the other surface (anode surface) of the metal base.
In the present embodiment, ni on the cathode plate 0.33 Cr 0.08 Mo 0.28 Ce 0.22 Al 0.07 P 0.02 High entropy alloy coating and Ni on the cathode face of the bipolar plate 0.33 Cr 0.08 Mo 0.28 Ce 0.22 Al 0.07 P 0.02 The high-entropy alloy coating is prepared by a magnetron co-sputtering method, and the preparation method comprises the following steps: firstly polishing 304L stainless steel (serving as a metal matrix of magnetron sputtering) with the thickness of 2mm by using sand paper, and then carrying out degreasing pretreatment; ni-Cr alloy targets with the purity of 99.99 percent (the atomic percentage ratio is 4:1), mo targets, ce targets, al targets and NiP targets are used as sputtering cathodes; vacuumizing to 5×10 -4 Under Pa, high-purity argon is introduced to adjust the required negative pressure to 0.5Pa, and then pre-sputtering is carried out for 10min at room temperature of 25 ℃ so as to carry out ion bombardment glow cleaning on each target; heating the oil-removed pretreated 304L stainless steel substrate to 200 ℃, continuously introducing high-purity argon as process gas, keeping the process air pressure in a vacuum chamber at 0.5Pa, adjusting the sputtering power of Ni-Cr alloy targets to 107W, the sputtering power of Mo targets to 71W, the sputtering power of Ce targets to 64W, the sputtering power of Al targets to 65W, the sputtering power of NiP targets to 110W, and the sputtering angle and the horizontal direction of a sputtering gun Performing magnetron sputtering at 90 degrees and 200 ℃ for 40min; ni with thickness of 2 μm is obtained on a 304L stainless steel substrate after degreasing pretreatment 0.33 Cr 0.08 Mo 0.28 Ce 0.22 Al 0.07 P 0.02 High entropy alloy coating.
In this example, the titanium oxide coating on the anode plate and the titanium oxide coating on the anode face of the bipolar plate were prepared using the same cold spray process as in example 1.
The system for wastewater hydrogen production in this example was at 600mA/cm 2 After 10min of operation under the current density of the non-diaphragm electrolytic tank, taking the electrolyzed wastewater at the electrolyte outlet of the non-diaphragm electrolytic tank for testing; the COD content in the electrolyzed wastewater is measured to be 58mg/L, the ammonia nitrogen content is measured to be 30mg/L, and the energy consumption for hydrogen production is measured to be 4.32kWh/kgH 2 。
Example 6
Example 6 is substantially the same as example 1 except that:
in the embodiment, the oil field wastewater flow is 900L/h, the chloride ion content is 12000mg/L, the COD content is 30000mg/L, and the ammonia nitrogen content is 360mg/L.
The system for wastewater hydrogen production in this example was operated at a current density of 600mA/cm 2 Performing electrolysis for 60min, and taking electrolyzed wastewater at an electrolyte outlet of the diaphragm-free electrolytic tank for testing; the COD content in the electrolyzed wastewater is measured to be 192mg/L, the ammonia nitrogen content is measured to be 31mg/L, and the hydrogen production energy consumption is measured to be 5.04kWh/kgH 2 。
Comparative example 1
Comparative example 1 is substantially the same as example 1 except that:
in the diaphragm-free electrolytic cell of the present comparative example, the cathode plate comprises a metal base (304L stainless steel substrate having a thickness of 2 mm) and a Ni-based high-entropy alloy coating (Ni having a thickness of 2 μm) formed on the metal base 0.10 Cr 0.17 Mo 0.30 Co 0.30 Al 0.13 A high entropy alloy coating); the anode plate comprises a metal matrix (304L stainless steel substrate with the thickness of 2 mm) and a titanium oxide coating layer with the thickness of 2 mu m formed on the metal matrixEach of the bipolar plates comprises a metal base (304L stainless steel substrate with a thickness of 2 mm), a Ni-based high-entropy alloy coating (Ni with a thickness of 2 μm) formed on one side (cathode side) of the metal base 0.10 Cr 0.17 Mo 0.30 Co 0.30 Al 0.13 High entropy alloy coating) and a titanium oxide coating layer having a thickness of 2 μm formed on the other surface (anode surface) of the metal base.
In this comparative example, ni on the cathode plate 0.10 Cr 0.17 Mo 0.30 Co 0.30 Al 0.13 High entropy alloy coating and Ni on the cathode face of the bipolar plate 0.10 Cr 0.17 Mo 0.30 Co 0.30 Al 0.13 The high-entropy alloy coating is prepared by a magnetron co-sputtering method, and the preparation method comprises the following steps: firstly polishing 304L stainless steel (serving as a metal matrix of magnetron sputtering) with the thickness of 2mm by using sand paper, and then carrying out degreasing pretreatment; ni target, cr target, mo target, co target and Al target with purity of 99.99% are used as sputtering cathode, and vacuum is pumped until the background vacuum reaches 5×10 -4 Under Pa, high-purity argon is introduced to adjust the required negative pressure to 0.5Pa, and then pre-sputtering is carried out for 10min at room temperature of 25 ℃ so as to carry out ion bombardment glow cleaning on each target; continuously introducing high-purity argon as process gas, keeping the process air pressure in the vacuum chamber at 0.5Pa, adjusting the sputtering power of the Ni target to 43W, the sputtering power of the Cr target to 97W, the sputtering power of the Mo target to 80W, the sputtering power of the Co target to 63W, the sputtering power of the Al target to 78W, the sputtering angle of the sputtering gun to 90 degrees with the horizontal direction, and performing magnetron sputtering at room temperature of 25 ℃ for 40min to obtain Ni with the thickness of 2 mu m on the 304L stainless steel substrate after the degreasing pretreatment 0.10 Cr 0.17 Mo 0.30 Co 0.30 Al 0.13 High entropy alloy coating.
In this comparative example, the titanium oxide coating on the anode plate and the titanium oxide coating on the anode face of the bipolar plate were prepared using the same cold spray process as in example 1.
The system for wastewater hydrogen production in this comparative example was at 600mA/cm 2 After 10min of operation at current density in a diaphragm-free electrolyzerTaking the electrolyzed wastewater at the solution outlet for testing; the COD content in the electrolyzed wastewater is measured to be 56mg/L, the ammonia nitrogen content is measured to be 29mg/L, and the hydrogen production energy consumption is measured to be 5.17kWh/kgH 2 。
Comparative example 2
Comparative example 2 is substantially the same as example 1 except that:
In the diaphragm-free electrolytic cell of the present comparative example, the cathode plate comprises a metal base (304L stainless steel substrate having a thickness of 2 mm) and Cu having a thickness of 2 μm formed on the metal base 0.20 Cr 0.12 Mo 0.30 Co 0.30 Al 0.08 A high entropy alloy coating; the anode plate comprises a metal base (304L stainless steel substrate with the thickness of 2 mm) and a titanium oxide coating layer with the thickness of 2 μm formed on the metal base, each bipolar plate comprises a metal base (304L stainless steel substrate with the thickness of 2 mm), cu with the thickness of 2 μm formed on one side (cathode side) of the metal base 0.20 Cr 0.12 Mo 0.30 Co 0.30 Al 0.08 A high-entropy alloy coating layer and a titanium oxide coating layer having a thickness of 2 μm formed on the other surface (anode surface) of the metal substrate.
In this comparative example, cu on the cathode plate 0.20 Cr 0.12 Mo 0.30 Co 0.30 Al 0.08 High entropy alloy coating and Cu on cathode face of said bipolar plate 0.20 Cr 0.12 Mo 0.30 Co 0.30 Al 0.08 The high-entropy alloy coating is prepared by a magnetron co-sputtering method, and the preparation method comprises the following steps: firstly polishing 304L stainless steel (serving as a metal matrix of magnetron sputtering) with the thickness of 2mm by using sand paper, and then carrying out degreasing pretreatment; a Cu target, a Cr target, a Mo target, a Co target and an Al target with the purity of 99.99 percent are used as sputtering cathodes; vacuumizing to 5×10 -4 Under Pa, high-purity argon is introduced to adjust the required negative pressure to 0.5Pa, and then pre-sputtering is carried out for 10min at room temperature of 25 ℃ so as to carry out ion bombardment glow cleaning on each target; continuously introducing high-purity argon as process gas, keeping the process air pressure in the vacuum chamber at 0.5Pa, then adjusting the sputtering power of the Cu target to 63W,the sputtering power of the Cr target is 88W, the sputtering power of the Mo target is 80W, the sputtering power of the Co target is 63W, the sputtering power of the Al target is 70W, the sputtering angle of the sputtering gun is 90 degrees with the horizontal direction, the magnetron sputtering is carried out at the room temperature of 25 ℃ for 40min, and Cu with the thickness of 2 mu m is obtained on the 304L stainless steel substrate after the degreasing pretreatment 0.20 Cr 0.12 Mo 0.30 Co 0.30 Al 0.08 High entropy alloy coating.
In this comparative example, the titanium oxide coating on the anode plate and the titanium oxide coating on the anode face of the bipolar plate were prepared using the same cold spray process as in example 1.
The system for wastewater hydrogen production in this comparative example was at 600mA/cm 2 After 10min of operation under the current density of the non-diaphragm electrolytic tank, taking the electrolyzed wastewater at the electrolyte outlet of the non-diaphragm electrolytic tank for testing; the COD content in the electrolyzed wastewater is measured to be 62mg/L, the ammonia nitrogen content is measured to be 34mg/L, and the hydrogen production energy consumption is measured to be 5.49kWh/kgH 2 。
Comparative example 3
Comparative example 3 is substantially the same as example 1 except that:
The anode plate in this comparative example was a 304L stainless steel plate having a thickness of 2mm, and each of the bipolar plates included a metal base (304L stainless steel substrate having a thickness of 2 mm) and a Ni-based high-entropy alloy coating (Ni 0.35 Cr 0.08 Mo 0.30 Co 0.20 Al 0.07 High-entropy alloy coating) is used as a cathode, and in the bipolar plate, the other side of the metal matrix is not sprayed with a titanium oxide coating, and a 304L stainless steel substrate directly leaks out to serve as an anode.
In this comparative example, ni on the cathode plate 0.35 Cr 0.08 Mo 0.30 Co 0.20 Al 0.07 High entropy alloy coating and Ni on the cathode face of the bipolar plate 0.35 Cr 0.08 Mo 0.30 Co 0.20 Al 0.07 The high entropy alloy coatings were all prepared by the same magnetron co-sputtering method as in example 1.
The system for wastewater hydrogen production in this comparative exampleIs unified at 600mA/cm 2 After 10min of operation under the current density of the non-diaphragm electrolytic tank, taking the electrolyzed wastewater at the electrolyte outlet of the non-diaphragm electrolytic tank for testing; the COD content in the electrolyzed wastewater is 1093mg/L, the ammonia nitrogen content is 227mg/L, and the hydrogen production energy consumption is 4.93kWh/kgH 2 。
Comparative example 4
Comparative example 4 is substantially the same as example 1 except that:
in the diaphragm-free electrolytic cell of the present comparative example, the cathode plate comprises a metal base (304L stainless steel substrate having a thickness of 2 mm) and a Ni-based high-entropy alloy coating (Ni having a thickness of 2 μm) formed on the metal base 0.35 Cr 0.08 Fe 0.30 Nb 0.20 Al 0.07 A high entropy alloy coating); the anode plate comprises a metal base (304L stainless steel substrate with the thickness of 2 mm) and a titanium oxide coating with the thickness of 2 μm formed on the metal base, each of the bipolar plates comprises a metal base (304L stainless steel substrate with the thickness of 2 mm), a Ni-based high-entropy alloy coating (Ni with the thickness of 2 μm) formed on one side (cathode side) of the metal base 0.35 Cr 0.08 Fe 0.30 Nb 0.20 Al 0.07 High entropy alloy coating) and a titanium oxide coating layer having a thickness of 2 μm formed on the other surface (anode surface) of the metal base.
In this comparative example, ni on the cathode plate 0.35 Cr 0.08 Fe 0.30 Nb 0.20 Al 0.07 High entropy alloy coating and Ni on the cathode face of the bipolar plate 0.35 Cr 0.08 Fe 0.30 Nb 0.20 Al 0.07 The high-entropy alloy coating is prepared by a magnetron co-sputtering method, and the preparation method comprises the following steps: firstly polishing 304L stainless steel (serving as a metal matrix of magnetron sputtering) with the thickness of 2mm by using sand paper, and then carrying out degreasing pretreatment; ni targets, cr targets, fe targets, nb targets and Al targets with the purity of 99.99 percent are used as sputtering cathodes; vacuumizing to 5×10 -4 Under Pa, high-purity argon is introduced to adjust the required negative pressure to 0.5Pa, and then pre-sputtering is carried out for 10min at room temperature of 25 ℃ to carry out ion bombardment on each target material Firing and cleaning; continuously introducing high-purity argon as process gas, keeping the process air pressure in the vacuum chamber at 0.5Pa, then adjusting the sputtering power of the Ni target to 75W, the sputtering power of the Cr target to 85W, the sputtering power of the Fe target to 94W, the sputtering power of the Nb target to 113W, the sputtering power of the Al target to 70W, the sputtering angle of the sputtering gun to 90 degrees with the horizontal direction, and performing magnetron sputtering at room temperature of 25 ℃ for 40min to obtain Ni with the thickness of 2 mu m on the 304L stainless steel substrate after the degreasing pretreatment 0.35 Cr 0.08 Fe 0.30 Nb 0.20 Al 0.07 High entropy alloy coating.
In the comparative example, the titanium oxide coating on the anode plate and the titanium oxide coating on the anode face of the bipolar plate were prepared using the same cold spray process as in example 1.
The system for wastewater hydrogen production in this comparative example was at 600mA/cm 2 After 10min of operation under the current density of the non-diaphragm electrolytic tank, taking the electrolyzed wastewater at the electrolyte outlet of the non-diaphragm electrolytic tank for testing; the COD content in the electrolyzed wastewater is measured to be 61mg/L, the ammonia nitrogen content is measured to be 44mg/L, and the hydrogen production energy consumption is measured to be 5.07kWh/kgH 2 。
Table 1: the results of the wastewater electrolysis hydrogen production performed by the system for wastewater hydrogen production in each example and each comparative example of the present invention were compared.
The invention is not described in detail in a manner known to those skilled in the art.
In the description of the present invention, it should also be noted that, unless explicitly specified and limited otherwise, the term "connected" should be construed broadly, and for example, it may be a fixed connection, a removable connection, or an integral connection, or an electrical connection, or a communication connection, etc.; may be directly connected, or indirectly connected through an intermediate medium, etc. The specific meaning of the term in the present invention can be understood as appropriate to one of ordinary skill in the art.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (6)
1. A diaphragm-free electrolytic cell for producing hydrogen from waste water, which is characterized in that:
the diaphragm-free electrolytic tank comprises N electrolytic cells connected in series, and each electrolytic cell comprises a cathode and an anode; n is more than or equal to 2;
The diaphragm-free electrolytic tank comprises a cathode plate and an anode plate which are positioned at two ends, and a bipolar plate used for dividing the diaphragm-free electrolytic tank into N electrolytic cells, wherein the cathode plate is a cathode, the anode plate is an anode, one surface of the bipolar plate, which is close to the cathode plate, is an anode, one surface of the bipolar plate, which is close to the anode plate, is a cathode, and the distance between two adjacent bipolar plates is 10-50 mm;
the cathode plate and the anode plate are connected with an external power supply in an on-off mode, and the bipolar plate is also connected with the external power supply in an on-off mode, so that the work load of the diaphragm-free electrolytic tank can be flexibly adjusted; one end of the anode plate of the diaphragm-free electrolytic tank is provided with an electrolyte inlet, and one end of the cathode plate of the diaphragm-free electrolytic tank is provided with an electrolyte outlet; the top of the diaphragm-free electrolytic tank is provided with a gas-liquid collecting device for collecting a gas-liquid mixture generated by hydrogen production from wastewater, the diaphragm-free electrolytic tank is sequentially connected with a gas purifying system and a separating system through the gas-liquid collecting device, the gas-liquid mixture flows out of the gas-liquid collecting device and sequentially passes through the gas purifying system and the separating system to obtain hydrogen and liquid oxygen, and part of the obtained hydrogen is returned to the gas-liquid collecting device after heat exchange;
The cathode includes a metal substrate and a Ni-based high-entropy alloy coating formed on the metal substrate; the Ni-based high-entropy alloy coatingThe general formula of the components is as follows: ni (Ni) x A y B z Al w X, y, z, w are all atomic percentages, x+y+z+w=100%;
a is Cr, B is Mo and Co, x is more than or equal to 30% and less than or equal to 35%, y is more than or equal to 5% and less than or equal to 15%, in the Ni-based high-entropy alloy coating, the atomic percentage of Mo is 25-35%, and the atomic percentage of Co is 20-32%; or (b)
A is Cr, B is Mo, ce and P, x is more than or equal to 30% and less than or equal to 35%, y is more than or equal to 5% and less than or equal to 15%, in the Ni-based high-entropy alloy coating, the atomic percentage of Mo is 25-35%, the atomic percentage of Ce is 20-32%, and the atomic percentage of P is 0.3-2%;
the anode includes a metal substrate and an iridium oxide coating or ruthenium oxide coating or titanium oxide coating formed on the metal substrate.
2. The diaphragm-less electrolyzer of claim 1 characterized in that:
the Ni-based high-entropy alloy coating is prepared by a magnetron sputtering method, or is a porous Ni-based high-entropy alloy coating, and the preparation of the porous Ni-based high-entropy alloy coating is as follows: firstly preparing a Ni-based high-entropy alloy coating on the surface of a metal matrix by a magnetron sputtering method, and then performing dealloying treatment on the Ni-based high-entropy alloy coating formed on the metal matrix to obtain a porous Ni-based high-entropy alloy coating;
The technological parameters of the magnetron sputtering are as follows: background vacuum is not greater than 5×10 -4 Pa, the process air pressure is 0.4-0.7 Pa, the magnetron sputtering is carried out by using a direct current power supply, the power of the direct current power supply is 40-140W, and the magnetron sputtering time is 30-100 min;
before the Ni-based high-entropy alloy coating is prepared on the surface of a metal matrix by a magnetron sputtering method, performing ion bombardment glow cleaning on a target;
when the Ni-based high-entropy alloy coating contains P element, the temperature of magnetron sputtering is 180-200 ℃;
the thickness of the Ni-based high-entropy alloy coating is 0.6-8 mu m.
3. A system for producing hydrogen from wastewater, the system for producing hydrogen from wastewater comprising:
the device comprises a wastewater tank, a flow sensor, a diaphragm-free electrolytic tank, a gas purification system and a separation system which are connected in sequence; the diaphragm-free electrolytic cell is the diaphragm-free electrolytic cell according to claim 1 or 2;
the external power supply is used for providing electrolytic energy for the diaphragm-free electrolytic tank;
a storage system comprising a hydrogen storage system, a liquid oxygen storage system, and a hypochlorite storage tank;
the control system is respectively connected with the flow sensor, the external power supply, the diaphragm-free electrolytic tank, the gas purification system, the separation system and the hydrogen storage system.
4. A system according to claim 3, characterized in that:
the system for producing hydrogen from the wastewater also comprises a water delivery pump for delivering the wastewater in the wastewater tank, wherein the water delivery pump is arranged on a passage connected with the wastewater tank by the flow sensor;
the system for producing hydrogen from wastewater also comprises a solid waste collecting system, wherein the solid waste collecting system is used for collecting solid waste in a wastewater tank and/or solid waste in the diaphragm-free electrolytic tank, the system for producing hydrogen from wastewater also comprises a settling tank for solid-liquid separation, an inlet of the settling tank is connected with the diaphragm-free electrolytic tank, and an outlet of the settling tank is respectively connected with the solid waste collecting system and a hypochlorite storage tank;
the hydrogen storage system and the liquid oxygen storage system are connected with the separation system; and/or
The gas purification system comprises a filler, wherein the filler is solid calcium oxide and/or solid sodium hydroxide.
5. A system according to claim 3, characterized in that:
a heat exchanger is arranged between the gas purification system and the separation system;
the top of the diaphragm-free electrolytic tank is provided with a gas-liquid collecting device for collecting a gas-liquid mixture generated by hydrogen production from wastewater, the diaphragm-free electrolytic tank is sequentially connected with the gas purifying system and the separating system through the gas-liquid collecting device, the gas-liquid mixture flows out of the gas-liquid collecting device and then sequentially passes through the gas purifying system and the separating system to obtain hydrogen and liquid oxygen, and part of the obtained hydrogen is returned to the gas-liquid collecting device after heat exchange of a heat exchanger.
6. A method of operating a system for producing hydrogen from wastewater as claimed in any one of claims 3 to 5, wherein the method of operating comprises the steps of:
s1, acquiring a preset working condition parameter range of a system for producing hydrogen from wastewater by the control system according to wastewater flow, COD content, chloride ion content, ammonia nitrogen content and an external power supply power fluctuation range;
s2, after the control system receives the working condition information of the flow sensor, the diaphragm-free electrolytic cell, the gas purification system, the separation system and the hydrogen storage system, the working condition information is integrated and then the operating power of the diaphragm-free electrolytic cell is dynamically regulated and controlled, so that the working condition information is regulated to be within the working condition parameter range; in step S2, the operation power of the diaphragm-free electrolytic cell is regulated and controlled by regulating the number of the electrolytic cells operated in the diaphragm-free electrolytic cell.
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