Hydrogen production system and method for decoupling electrolysis of hydrazine-containing wastewater

Abstract

This invention discloses a decoupled hydrazine-containing wastewater electrolysis hydrogen production system and method, belonging to the field of electrochemistry. It comprises three processes: generating electricity through a renewable energy device, electrolytic hydrogen evolution, and chemical catalytic treatment of hydrazine-containing wastewater to produce nitrogen, achieving low-energy electrolysis hydrogen production from hydrazine-containing wastewater. A pair of redox media serves as charge transfer carriers circulating between the hydrogen evolution electrolysis cell and a separate chemical reactor. In the hydrogen evolution electrolysis cell, hydrogen evolution occurs at the cathode, and oxidation of the reduced medium occurs at the anode. The resulting oxidized medium is recycled to the chemical reactor, where it spontaneously reduces hydrazine under the action of a catalyst, releasing nitrogen. The overall process involves the electrolysis of hydrazine. This invention directly reduces the energy consumption of hydrogen production electrolysis, avoids problems such as the generation of harmful chlorine in high-salt wastewater hydrogen production, and has the advantages of temporal and spatial decoupling, adapting to the fluctuations in renewable energy power generation. It also solves safety issues caused by hydrogen and oxygen cross-contamination and removes hydrazine pollution from wastewater.

Description

Technical Field

[0001] This invention relates to the field of electrochemical technology, and in particular to a decoupled hydrazine-containing wastewater electrolysis hydrogen production system and method. Background Technology

[0002] Hydrogen energy, as a zero-pollution, high-calorific-value energy source, is the mainstream trend in future energy development. Currently, there are four main technological pathways for hydrogen production: alkaline water electrolysis, proton exchange membrane water electrolysis, anion exchange membrane water electrolysis, and solid oxide electrolysis. However, in current production methods, the hydrogen and oxygen produced at the anode and cathode may cross-contaminate, posing an explosion risk. Furthermore, common water electrolysis for hydrogen production often requires significant energy consumption due to the reaction kinetics of the oxygen evolution reaction (OER).

[0003] Meanwhile, hydrazine, with the chemical formula N₂H₄, is a highly toxic, colorless, and highly reducing compound with an odor similar to ammonia. As an important chemical raw material, hydrazine is widely used in foaming agents, rocket fuel, herbicides, and pharmaceuticals, among other applications. However, its production and use inevitably generate hydrazine-containing wastewater. Hydrazine is extremely toxic; once it enters the environment, it severely disrupts the natural ecological balance and directly threatens human health. Therefore, the effective decomposition and degradation of hydrazine-containing wastewater is of paramount importance for maintaining the safety of the Earth's ecological environment and protecting human life and health.

[0004] Currently, existing chemical oxidation methods for hydrazine-containing wastewater require the addition of oxidants such as potassium permanganate, resulting in a treatment cost of 10 yuan / ton, far exceeding the average cost of 0.8 yuan / ton for existing wastewater treatment. Furthermore, these methods are prone to generating secondary pollution from manganese slag. Biodegradation methods have long treatment cycles and are only suitable for wastewater with a concentration <100 mg / L. This invention provides a pollution-free, decoupled, low-energy electrolytic hydrogen production method for hydrazine-containing wastewater, addressing the current problems of high energy consumption and hydrogen-oxygen mixing in hydrogen production. It can also treat hydrazine-containing wastewater, achieving environmental value. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a decoupled, low-energy electrolytic hydrogen production system and method for hydrazine-containing wastewater. It features spatiotemporal decoupling, enabling low-energy, high-safety hydrogen production and treatment of hydrazine-containing wastewater, thus achieving environmental value.

[0006] The objective of this invention is achieved through the following solution: A decoupled hydrazine-containing wastewater electrolysis hydrogen production system includes: a renewable energy power generation device, an energy storage system with power detection, a cathode plate with a catalytic electrode, a cathode reaction zone, an anion exchange membrane, an anode reaction zone, an anode plate with a catalytic electrode, a cathode liquid outlet pipe, a cathode liquid outlet pump, a cathode liquid gas-liquid separator, a cathode liquid inlet pipe, an anode liquid outlet pipe, an anode liquid outlet pump, a reaction buffer, an anode liquid inlet pipe, a reaction liquid inlet pipe, a reaction liquid inlet pump, a chemical reactor, a reaction liquid outlet pipe, a nitrogen collection tank, a hydrogen collection tank, and a safety protection device; The system utilizes renewable energy power generation devices to obtain operating power, which is then stored by an energy storage system that includes power detection. A cathode reaction zone is provided on one side of the anion exchange membrane, containing a cathode plate with a catalytic electrode. An anode reaction zone is provided on the other side of the anion exchange membrane, containing an anode plate with a catalytic electrode. The cathode side of the entire hydrazine-containing wastewater electrolysis hydrogen production system is equipped with a cathode liquid gas-liquid separator. The cathode plate containing the catalytic electrode is connected to the cathode liquid outlet pipe, which is equipped with a cathode liquid outlet pump and connected to the cathode liquid gas-liquid separator. The cathode liquid gas-liquid separator is equipped with a hydrogen outlet and connected to a hydrogen collection tank. The cathode liquid gas-liquid separator is also connected to the cathode liquid inlet pipe. The entire hydrazine-containing wastewater electrolysis hydrogen production system is equipped with a liquid addition and circulation device on the anode side. The anode plate containing the catalytic electrode is connected to the anolyte outlet pipe, which is equipped with an anolyte outlet pump. The anolyte outlet pipe is connected to one side of the reaction buffer, and the reaction buffer is also connected to the anolyte inlet pipe. The anolyte inlet pipe is connected to the anode plate containing the catalytic electrode. The other side of the reaction buffer is connected to the reaction liquid inlet pipe, which is equipped with a reaction liquid inlet pump and connected to a chemical reactor that can receive liquid. The chemical reactor is connected to the reaction liquid outlet pipe and finally to the reaction buffer. The upper part of the chemical reactor is connected to a nitrogen collection tank. Safety protection devices are installed between the renewable energy power generation unit and the electrolytic cell.

[0007] Furthermore, both the cathode liquid outlet pipe and the cathode liquid inlet pipe are inserted into the interior of the cathode reaction zone; both the anolyte outlet pipe and the anolyte inlet pipe are inserted into the interior of the anolyte reaction zone; and the pipes and pump bodies that come into contact with the corrosive medium are made of fluoroplastics or titanium alloy materials.

[0008] Furthermore, the interior of the anode reaction zone is filled with an alkaline anode reaction solution with a pH value controlled between 12 and 14.

[0009] Furthermore, the interior of the anode reaction zone is filled with an anode reaction solution containing any one of the following redox media: [Fe(CN)6] 3- / [Fe(CN)6] 4- [Ru(bpy)3]2+ / [Ru(bpy)3] 3+ (VO2) + / (VO)2 + I – / I 3– An alkaline solution of 2,3-dihydroxyphenazine DHP or 2-amino-3-hydroxyphenazine.

[0010] Furthermore, the chemical reactor is internally equipped with a device for adding hydrazine and hydrazine-containing liquid. The corresponding catalyst includes any one of the following: platinum carbon catalyst, phosphating foamed nickel catalyst, cobalt nitrogen doped carbon nanosheets, Ru-VOx / Ni3S2, manganese cobalt sulfide catalyst, cobalt fluoride phosphide F-CoP, cobalt phosphide CoP, Pt@NiFc-MO, Mn@Ni3N-Co3N / NF, Ni3N-Co3NPNAs / NF, and CoFeNiCrMn / N.

[0011] Furthermore, the safety protection device includes a nitrogen charging unit, an electrolysis efficiency monitoring unit, and a multi-parameter monitoring module. The multi-parameter monitoring module is used to monitor the pressure, temperature, hydrazine concentration, and pH value of the medium in the reaction zone in real time. When the system parameters exceed the safety threshold, an early warning is triggered and emergency measures are taken.

[0012] Furthermore, a carbon felt electrode is disposed within the anode plate containing the catalytic electrode, and a hydrogen evolution catalytic electrode is disposed within the cathode plate containing the catalytic electrode.

[0013] A decoupled method for producing hydrogen from hydrazine-containing wastewater by electrolysis includes the following steps: The process achieves low-energy electrolytic hydrogen production from hydrazine-containing wastewater through three steps: generating electricity using renewable energy devices, electrolytic hydrogen evolution, and chemical catalytic treatment of hydrazine-containing wastewater to produce nitrogen. A pair of redox media serves as charge transfer carriers circulating between the hydrogen evolution electrolysis cell and a separate chemical reactor. In the hydrogen evolution electrolysis cell, hydrogen evolution occurs at the cathode, while oxidation of the reduced media occurs at the anode. The resulting oxidized media is recycled to the chemical reactor, where it spontaneously reduces hydrazine under the action of a catalyst, releasing nitrogen. The overall process involves the electrolysis of hydrazine.

[0014] A decoupled method for producing hydrogen from hydrazine-containing wastewater by electrolysis includes the following steps: S1, Construct a decoupled hydrazine-containing wastewater electrolysis hydrogen production system as described in any of the above items; S2, the decoupled hydrazine-containing wastewater electrolysis hydrogen production system operates as follows: When using the redox medium 2,3-dihydroxyphenazine (DHP), DHP is dissolved in an alkaline solution and oxidized to the oxidized state of DHP in the anode reaction zone. After sufficient reaction, it is fed into the reaction buffer for storage through the anolyte outlet pipe and the anolyte outlet pump. The DHP in the reaction buffer is fed into the chemical reactor through the reaction liquid inlet pipe 16 and the reaction liquid inlet pump. Under the action of the catalyst, it reacts with hydrazine (N2H4) in the hydrazine-containing wastewater to the reduced state of DHPH2 and releases nitrogen gas. The generated nitrogen gas is collected in a nitrogen collection tank. The DHPH2 obtained from the reaction is returned to the reaction buffer through the reaction liquid outlet pipe. After the DHP in the reaction buffer and the chemical reactor is completely reacted to DHPH2, it is returned to the anode reaction zone through the anolyte inlet pipe. Electrolytic hydrogen reaction occurs in the cathode reaction zone. The cathode reaction solution, through the cathode solution outlet pipe, enters the cathode solution gas-liquid separator under the action of the cathode solution outlet pump. The hydrogen entrained in the cathode solution after the reaction will enter the hydrogen collection tank. The separated cathode solution returns to the cathode solution reaction zone through the cathode solution inlet pipe. During this process, the anion exchange membrane is used to separate the anode and cathode. It will migrate from the cathode to the anode through the anion exchange membrane, ensuring the overall electroneutrality of the decoupled hydrazine-containing wastewater hydrogen production system; at the same time, some of the water produced in the anode reaction zone will pass through the anion exchange membrane into the cathode reaction zone.

[0015] Furthermore, it also includes the following steps: The decoupled hydrazine-containing wastewater electrolysis hydrogen production system operates in an intermittent mode and includes the following liquid addition process: anolyte is drawn from the reaction buffer through the anolyte inlet pipe and transported to the anode reaction zone to complete the liquid addition operation; hydrazine-containing wastewater is added to the chemical reactor, reacts fully with the DHP in the reaction buffer, and is then transported to the reaction buffer through the reaction liquid outlet pipe; the liquid filling the cathode reaction zone includes seawater, mine water, or saline wastewater; the hydrazine-containing solution added to the chemical reactor includes hydrazine-containing wastewater.

[0016] Furthermore, the hydrogen evolution catalytic electrode disposed within the cathode plate containing the catalytic electrode includes any one of the following hydrogen evolution catalysts: platinum-nickel plating mesh, platinum-carbon catalyst, perovskite-based self-reconstructed catalyst Ca2CoRuO6, nickel-based carbon nanotube nickel hydroxide CNTs-Ni-Ni, copper-based catalyst DNTs-Cu, Mo5N6 nanosheet catalyst, Mn-NiO / Ni / NF catalyst, and NiCoP / NF catalyst.

[0017] The beneficial effects of this invention include: This invention proposes a decoupled hydrogen production strategy for hydrazine-containing wastewater electrolysis, enabling low-energy hydrogen production from hydrazine-containing wastewater. The electricity required for electrolysis can be generated using renewable energy devices such as solar photovoltaic units and wind turbines. The system utilizes a redox medium to decouple the hydrazine-containing wastewater electrolysis hydrogen production system, achieving hydrogen evolution at the cathode and nitrogen production in the chemical reactor. This avoids problems such as the generation of harmful chlorine gas in high-salinity wastewater hydrogen production. Furthermore, the spatiotemporal decoupling avoids the explosion risks associated with hydrogen-oxygen mixtures, and the system can treat hydrazine-containing wastewater, achieving environmental value. This also contributes to future technological development in the field of other saline wastewater, such as seawater or mine water.

[0018] This invention achieves low-energy electrolytic hydrogen production from hydrazine-containing wastewater through three main processes: power generation from a renewable energy device, electrolytic hydrogen evolution, and nitrogen production from hydrazine-containing wastewater via chemical catalytic treatment. A pair of redox media serves as charge transfer carriers circulating between the hydrogen evolution electrolysis cell and a separate chemical reactor. In the hydrogen evolution electrolysis cell, hydrogen evolution occurs at the cathode, while oxidation of the reduced medium occurs at the anode. The resulting oxidized medium is recycled to the chemical reactor, where it spontaneously reduces hydrazine under the action of a catalyst, releasing nitrogen. The overall process involves the electrolysis of hydrazine. This approach directly reduces the energy consumption of hydrogen electrolysis, avoids problems such as the generation of harmful chlorine in hydrogen production from high-salt wastewater, and offers the advantages of temporal and spatial decoupling, adapting to the fluctuations in renewable energy power generation. It also solves safety issues caused by hydrogen and oxygen cross-contamination and removes hydrazine pollution from wastewater. Attached Figure Description

[0019] To facilitate a clear explanation of the technical solutions in the embodiments of the present invention or the prior art, the relevant drawings are briefly described below. It should be noted that the drawings described below are only schematic diagrams of some embodiments of the present invention. Those skilled in the art can derive other relevant drawings from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram illustrating the operation process of the system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the system structure according to an embodiment of the present invention; Figure 3 (a) is the LSV curve of DHP in the reduced state of alkaline hydrazine solution, (b) is the voltage operation of DHP under different current densities, and (c) is the Vt graph of the anode for 12 hours of electrolytic hydrogen production. 1-Renewable energy power generation device; 2-Energy storage system with detection; 3-Cathode plate with catalytic electrode; 4-Cathode reaction zone; 5-Anion exchange membrane; 6-Anode reaction zone; 7-Anode plate with catalytic electrode; 8-Cathode liquid outlet pipe; 9-Cathode liquid outlet pump; 10-Cathode liquid gas-liquid separator; 11-Cathode liquid inlet pipe; 12-Anode liquid outlet pipe; 13-Anode liquid outlet pump; 14-Reaction buffer; 15-Anode liquid inlet pipe; 16-Reaction liquid inlet pipe; 17-Reaction liquid inlet pump; 18-Chemical reactor; 19-Reaction liquid outlet pipe; 20-Nitrogen collection tank; 21-Hydrogen collection tank; 22-Safety protection device. Detailed Implementation

[0021] All features of the embodiments disclosed in this specification, as well as steps in the methods or processes implicitly disclosed, may be combined, extended, or replaced in any manner, except for mutually exclusive features and / or steps.

[0022] To address the problems existing in the prior art, this invention proposes an innovative decoupled, low-energy electrolytic hydrogen production system and method for hydrazine-containing wastewater. For example... Figure 1 , Figure 2 and Figure 3 As shown, this method achieves direct hydrogen production from hydrazine-containing wastewater by optimizing the principle and structural design of decoupled direct electrolysis technology. Specifically, in a preferred embodiment, it includes three core processes: first, generating electricity using renewable energy devices; second, electrolytically eluing hydrogen through a hydrogen evolution electrolysis cell; and third, generating nitrogen gas through chemical catalytic oxidation. In this process, a pair of redox media act as carriers for proton-coordinated charge transfer, circulating between the anode reaction zone, the reaction buffer, and the chemical reactor. In the hydrogen evolution electrolysis cell, hydrogen evolution occurs at the cathode, while oxidation of the media occurs at the anode. The overall reaction is the electrolysis of hydrazine. This innovative design can significantly reduce hydrogen production energy consumption, improve hydrogen production efficiency, and optimize the reaction process.

[0023] It should be noted that, within the scope of protection defined in the claims of this invention, the following embodiments can be combined and / or extended or replaced in any logical manner from the above specific embodiments, such as the disclosed technical principles, disclosed technical features or implicitly disclosed technical features.

[0024] In an optional implementation, this embodiment provides a decoupled hydrazine-containing wastewater electrolysis hydrogen production system. Based on the above implementation scheme, it includes: a renewable energy power generation device 1, an energy storage system with power detection 2, a cathode plate with a catalytic electrode 3, a cathode reaction zone 4, an anion exchange membrane 5, an anode reaction zone 6, an anode plate with a catalytic electrode 7, a cathode liquid outlet pipe 8, a cathode liquid outlet pump 9, a cathode liquid gas-liquid separator 10, a hydrogen collection tank 21, a cathode liquid inlet pipe 11, an anode liquid outlet pipe 12, an anode liquid outlet pump 13, a reaction buffer 14, an anode liquid inlet pipe 15, a reaction liquid inlet pipe 16, a reaction liquid inlet pump 17, a chemical reactor 18, a reaction liquid outlet pipe 19, a nitrogen collection tank 20, and a safety protection device 22. The safety protection device 22 is installed between the renewable energy power generation device 1 and the electrolytic cell. The entire hydrazine-containing wastewater electrolysis hydrogen production system is connected to a renewable energy power generation device 1 via wires to obtain operating power. After the power is obtained, it is stored by an energy storage system 2 with power detection. A cathode reaction zone 4 is provided on one side of the anion exchange membrane 5, and a cathode plate 3 with a catalytic electrode is provided in the cathode reaction zone 4. An anode reaction zone 6 is provided on the other side of the anion exchange membrane 5, and an anode plate 7 with a catalytic electrode is provided in the anode reaction zone 6. The entire hydrazine-containing wastewater electrolysis hydrogen production system is equipped with a gas-liquid separation device (cathode liquid gas-liquid separator 10) on the cathode side. The cathode plate 3 containing the catalytic electrode is connected to the cathode liquid outlet pipe 8, which is equipped with a cathode liquid outlet pump 9 and connected to the cathode liquid gas-liquid separator 10. The cathode liquid gas-liquid separator 10 is equipped with a hydrogen outlet and is connected to the hydrogen collection tank 21. The cathode liquid gas-liquid separator 10 is also connected to the cathode liquid inlet pipe 11. The anode side of the entire hydrazine-containing wastewater electrolysis hydrogen production system is equipped with a liquid addition and circulation device. The anode plate 7 containing the catalytic electrode is connected to the anolyte outlet pipe 12. The anolyte outlet pipe 12 is equipped with an anolyte outlet pump 13. The anolyte outlet pipe 12 is connected to one side of the reaction buffer 14, and the reaction buffer 14 is connected to the anolyte inlet pipe 15. The anolyte inlet pipe 15 is connected to the anode plate 7 containing the catalytic electrode. The other side of the reaction buffer 14 is connected to the reaction liquid inlet pipe 16, which is equipped with a reaction liquid inlet pump 17 and connected to a chemical reactor 18 that can receive liquid. The chemical reactor 18 is connected to the reaction liquid outlet pipe 19 and finally connected to the reaction buffer 14. The upper part of the chemical reactor 18 is connected to a nitrogen collection tank 20.

[0025] In an optional embodiment, a nitrogen charging unit is installed within the safety protection device. This nitrogen charging unit is connected to the cathode reaction zone and the cathode liquid inlet pipe via pipelines. When the power generation is low, the safety protection device is triggered, activating interlocking protection to ensure the isolation of the hydrogen unit and guarantee safety. Furthermore, the device also includes a power generation detection unit and an electrolysis efficiency monitoring unit. The power generation detection unit detects the power generation, while the multi-parameter monitoring module monitors key parameters such as reaction zone pressure, temperature, hydrazine concentration, and medium pH value in real time. When parameters exceed safety thresholds, an early warning is automatically triggered, and emergency measures are taken (such as stopping feeding, increasing nitrogen purging, and reducing temperature and pressure).

[0026] In an optional implementation, based on the above embodiments, the renewable energy power generation device 1 is connected to the anode plate 7 containing the catalytic electrode, the cathode plate 3 containing the catalytic electrode, and each infusion pump via wires.

[0027] In an optional implementation, based on the above embodiments, both the cathode liquid outlet pipe 8 and the cathode liquid inlet pipe 11 need to be inserted into the interior of the cathode reaction zone 4; both the anolyte outlet pipe 12 and the anolyte inlet pipe 15 need to be inserted into the interior of the anolyte reaction zone 6.

[0028] In an optional implementation, based on the above embodiments, the interior of the cathode reaction zone can be filled with seawater, mine water, or other saline wastewater.

[0029] In an optional embodiment, based on the above embodiments, the anode reaction zone 6 is filled with an alkaline solution containing a redox medium (DHP / DHPH2), and hydrazine-containing wastewater is added to the chemical reactor 18 via an additive device. The anode reaction zone 6 may also contain other soluble or insoluble redox media with redox properties. Redox media include, but are not limited to: soluble redox substances including, but not limited to, phosphomolybdic acid, silicotungstic acid, vanadium oxide ions, anthraquinone-2,7-disulfonic acid, and iron oxide; and solid redox media including, but not limited to, nickel hydroxide, manganese oxide, and titanium oxide.

[0030] In an optional embodiment, based on the above embodiments, a carbon felt electrode is disposed within the anode plate containing the catalytic electrode, and a hydrogen evolution electrocatalyst is disposed within the cathode plate containing the catalytic electrode. The chemical reactor is provided with a hydrazine-containing oxidation reaction catalyst, including but not limited to: platinum-carbon catalyst, phosphating foamed nickel catalyst, cobalt-nitrogen-doped carbon nanosheets, Ru-VOx / Ni3S2, manganese cobalt sulfide catalyst, cobalt fluoride phosphide F-CoP, cobalt phosphide CoP, Ni3N-Co3NPNAs / NF (a specific morphology derivative of Ni3N-Co3N), and any one of CoFeNiCrMn / N.

[0031] In an optional embodiment, based on the above embodiments, a carbon felt electrode is provided in the anode plate 7 containing the catalytic electrode, and a hydrogen evolution electrocatalyst is provided in the cathode plate 3 containing the catalytic electrode.

[0032] In an optional implementation, based on the above embodiments, a decoupled method for producing hydrogen from hydrazine-containing wastewater by electrolysis includes the following steps: S1, Construct a decoupled hydrazine-containing wastewater electrolysis hydrogen production system as described in the above embodiments; S2, the decoupled hydrazine-containing wastewater electrolysis hydrogen production system operates as follows: 2,3-dihydroxyphenazine (DHP) is dissolved in an alkaline solution using the redox medium. In the anode reaction zone 6, it is oxidized to the DHP oxidized state. After complete reaction, the DHP is pumped through the anolyte outlet pipe 12 and then through the anolyte outlet pump 13 into the reaction buffer 14 for storage. The DHP in the reaction buffer 14 is then pumped through the reaction liquid inlet pipe 16 and then through the reaction liquid inlet pump 17 into the chemical reactor 18. Under the action of a catalyst, it undergoes catalytic oxidation with hydrazine (N2H4) to generate DHPH2 in the reduced state, releasing nitrogen gas. The generated nitrogen gas is collected in the nitrogen collection tank 20. The resulting DHPH2 is returned to the reaction buffer 14 through the reaction liquid outlet pipe 19. After the DHP in the reaction buffer 14 and the chemical reactor 18 is completely reacted to form DHPH2, it is returned to the anode reaction zone 6 through the anolyte inlet pipe 15.

[0033] In the cathode reaction zone 4 of the hydrazine-containing wastewater electrolysis hydrogen production system, an electrolytic hydrogen release reaction occurs. The cathode reaction liquid enters the cathode liquid gas-liquid separator 10 through the cathode liquid outlet pipe 8 and the cathode liquid outlet pump 9. The hydrogen entrained in the cathode liquid after the reaction will enter the hydrogen collection tank 21. The separated cathode liquid returns to the cathode liquid reaction zone 4 through the cathode liquid inlet pipe 11. During this process, the anion exchange membrane 5 is used to separate the anode and cathode. The water will migrate from the cathode to the anode through the anion exchange membrane, ensuring the overall electroneutrality of the decoupled hydrazine-containing wastewater hydrogen production system. Simultaneously, some of the water produced in the anode reaction zone 6 will pass through the anion exchange membrane 5 into the cathode reaction zone 4.

[0034] In an optional implementation, the decoupled hydrazine-containing wastewater electrolysis hydrogen production system mainly operates in an intermittent mode. Its liquid addition process is as follows: the anolyte is drawn from the reaction buffer 14 through the anolyte inlet pipe 15 and transported to the anode reaction zone 6 to complete the liquid addition operation; while the liquid in the reaction buffer 14 is mainly produced by adding hydrazine-containing wastewater to the chemical reactor 18, reacting fully with the DHP in the reaction buffer, and then being transported to the reaction buffer 14 through the reaction liquid outlet pipe 19. This achieves spatiotemporal decoupling of electrolysis hydrogen production, eliminates the risk of hydrogen-oxygen mixing, consumes less energy due to the low potential of hydrazine oxidation electrolysis, and can efficiently treat hydrazine-containing wastewater, achieving both economic and environmental benefits.

[0035] It should be noted that when the renewable energy power generation is less than 50% of the system's rated power, the system can be designed to automatically stop electrolysis, shut down all liquid pumps, and introduce 0.1MPa nitrogen into the cathode liquid-gas-liquid separator, cathode liquid inlet pipe, and cathode reaction zone to isolate air; when the power generation recovers to more than 80% of the rated power, the system can be designed to automatically add liquid and restart electrolysis.

[0036] In a more specific embodiment, a type of highly soluble redox couple medium capable of reversible redox reactions is characterized by excellent redox cycling ability. After five thousand redox cycles in seawater, the redox medium exhibits a decay rate of <10%, demonstrating good cycleability and superior electrochemical reversible reaction stability.

[0037] A decoupled hydrogen production system for hydrazine-containing wastewater was constructed using DHP / DHPH2 as the redox medium to achieve decoupled electrolysis of hydrazine-containing wastewater for hydrogen production. The redox medium DHP / DHPH2 was used as a carrier for proton-coordinated charge transfer circulating between the anolyte and the chemical reactor. In the hydrogen evolution electrolysis cell, hydrogen evolution occurs in the cathode reaction zone 4, and the redox medium DHPH2, dissolved in an alkaline solution, is oxidized to DHP in the anolyte reaction zone 6 of the electrolysis cell. Cathode reaction: 2H₂O + 2e⁻ - →2OH - +H2↑ Anodic reaction: 2DHPH2 + 2OH - -2e - →2DHP+2H2O DHP enters the reaction buffer 14 via the anolyte outlet pipe 12 under the action of the anolyte outlet pump 13, and then enters the chemical reactor via the reaction liquid inlet pipe 16 under the action of the reaction liquid inlet pump 17. There, it reacts with the added hydrazine to generate DHPH2 and release nitrogen gas. Chemical reaction: 2DHP + N2H4 → N2 + 2DHPH2 The resulting DHPH2 returns to the reaction buffer 14 through the reaction liquid outlet pipe 19. After sufficient reaction, it returns to the anode reaction zone 6 through the anolyte inlet pipe 15, thus completing the stable circulation of the redox medium. The overall reaction is the electrolysis of hydrazine N2H4. After DHP replaces the oxygen evolution reaction, it spontaneously reduces to the original DHPH2 in the chemical reactor 18 and can be recycled repeatedly. The decoupled circulation of the redox medium achieves the separation of the hydrogen evolution reaction and the chemical reduction reaction in time and space. This feature is highly adaptable to the unstable nature of renewable energy power generation and avoids the risk of hydrogen-oxygen mixing caused by oxygen production, achieving low-energy hydrogen production and hydrazine-containing wastewater treatment.

[0038] In an optional implementation, based on the above embodiments, the decoupled hydrazine-containing wastewater electrolysis hydrogen production system can be made into a portable integrated device.

[0039] In an optional implementation, based on the above embodiments, the decoupled hydrazine-containing wastewater electrolysis hydrogen production system is installed in an environment such as a marine area or saline wastewater. It should be noted that the cathode area can use the aforementioned seawater or wastewater. The hydrazine-containing solution added to the chemical reactor 18 can be expanded to hydrazine-containing wastewater, and the anode area is filled with an alkaline solution containing a redox medium to achieve environmentally friendly and efficient hydrogen production.

[0040] In optional embodiments, based on the above embodiments, the hydrogen evolution catalyst is selected from any one of the following: platinum-plated nickel mesh, platinum-carbon catalyst, perovskite-based self-reconstructed catalyst Ca2CoRuO6, nickel-based carbon nanotube nickel hydroxide CNTs-Ni-Ni, copper-based catalyst DNTs-Cu, Mo5N6 nanosheet catalyst, Mn-NiO / Ni / NF catalyst, and NiCoP / NF catalyst; or extended catalysts such as molybdenum-based nickel foam catalyst, nickel-molybdenum-cobalt-based phosphide nickel foam NiMoCoP / NF, cobalt sulfide CoS, and platinum-doped nickel-molybdenum-based nickel foam Pt-NiMo / NF may be selected according to actual needs.

[0041] In summary, the present invention achieves energy conversion for treating hydrazine-containing wastewater without any input of its own energy, and can obtain clean hydrogen energy. It utilizes wind and solar photovoltaic units to autonomously obtain renewable energy, and then uses a decoupled hydrazine-containing wastewater electrolysis hydrogen production system to convert this energy into high-calorific-value, pollution-free hydrogen for use. The hydrogen production utilizes the decoupled principle of "electrochemical oxidation-chemical reduction," achieving low-energy consumption, high-efficiency, and environmentally friendly hydrogen energy acquisition. More specifically, it has the following advantages: This invention replaces the electrochemical oxygen evolution reaction with an oxidation reaction using a redox medium, thereby enhancing its competitiveness with the chlorination reaction from a fundamental kinetic perspective. This cleverly avoids the interference of inherent impurity ions during direct electrolysis of hydrogen from hydrazine-containing wastewater. Furthermore, because the redox medium has a lower potential, low-energy hydrogen production can be achieved.

[0042] This invention utilizes the principle of redox reaction, replacing the oxygen evolution reaction with an oxidation reaction in a redox medium, and spontaneously carrying out chemical reduction under the action of a catalyst. This avoids problems such as the generation of harmful chlorine gas in hydrogen production from salt wastewater. It separates hydrogen and nitrogen on both temporal and spatial scales, adapts to the unstable output characteristics of renewable energy power generation devices, and further avoids the generation of oxygen and the risk of hydrogen-oxygen mixing.

[0043] This invention utilizes renewable energy to achieve decoupled hydrogen production via a redox medium, enabling the treatment of hydrazine-containing wastewater. Furthermore, the cathode solution can be expanded to include seawater, mine water, or other saline wastewater, avoiding the high cost associated with electrolyzing only pure water. Simultaneously, the system's application scenarios will be greatly broadened.

[0044] This invention enables the redox medium DHP / DHPH2 to maintain excellent redox kinetics and stability in seawater. Based on this, by designing high-performance redox media with high capacity and appropriate potential, and by designing and preparing highly efficient hydrogen evolution electrocatalysts and chemical reaction catalysts, the efficiency of hydrogen production from hydrazine-containing wastewater electrolysis can be further improved, thereby enhancing cost-effectiveness and promoting efficient and high-quality development in related fields.

[0045] In addition to the embodiments described above, those skilled in the art can modify the present invention according to the disclosure of the present invention or in combination with knowledge and technology in related fields to obtain other embodiments. The features of these embodiments can be substituted for or combined with each other. As long as these modifications and variations conform to the spirit and scope of the present invention, they should be included within the protection scope of the claims of the present invention.

Claims

1. A decoupled hydrazine-containing wastewater electrolysis hydrogen production system, characterized in that, include: Renewable energy power generation equipment, energy storage system with power detection, cathode plate with catalytic electrode, cathode reaction zone, anion exchange membrane, anode reaction zone, anode plate with catalytic electrode, cathode liquid outlet pipe, cathode liquid outlet pump, cathode liquid gas-liquid separator, cathode liquid inlet pipe, anode liquid outlet pipe, anode liquid outlet pump, reaction buffer, anode liquid inlet pipe, reaction liquid inlet pipe, reaction liquid inlet pump, chemical reactor, reaction liquid outlet pipe, nitrogen collection tank, hydrogen collection tank and safety protection device; The system utilizes renewable energy power generation devices to obtain operating power, which is then stored by an energy storage system that includes power detection. A cathode reaction zone is provided on one side of the anion exchange membrane, containing a cathode plate with a catalytic electrode. An anode reaction zone is provided on the other side of the anion exchange membrane, containing an anode plate with a catalytic electrode. The cathode side of the entire hydrazine-containing wastewater electrolysis hydrogen production system is equipped with a cathode liquid gas-liquid separator. The cathode plate containing the catalytic electrode is connected to the cathode liquid outlet pipe, which is equipped with a cathode liquid outlet pump and connected to the cathode liquid gas-liquid separator. The cathode liquid gas-liquid separator is equipped with a hydrogen outlet and connected to a hydrogen collection tank. The cathode liquid gas-liquid separator is also connected to the cathode liquid inlet pipe. The entire hydrazine-containing wastewater electrolysis hydrogen production system is equipped with a liquid addition and circulation device on the anode side. The anode plate containing the catalytic electrode is connected to the anolyte outlet pipe, which is equipped with an anolyte outlet pump. The anolyte outlet pipe is connected to one side of the reaction buffer, and the reaction buffer is also connected to the anolyte inlet pipe. The anolyte inlet pipe is connected to the anode plate containing the catalytic electrode. The other side of the reaction buffer is connected to the reaction liquid inlet pipe, which is equipped with a reaction liquid inlet pump and connected to a chemical reactor that can receive liquid. The chemical reactor is connected to the reaction liquid outlet pipe and finally to the reaction buffer. The upper part of the chemical reactor is connected to a nitrogen collection tank. Safety protection devices are installed between the renewable energy power generation unit and the electrolytic cell.

2. The decoupled hydrazine-containing wastewater electrolysis hydrogen production system according to claim 1, characterized in that, The cathode liquid outlet pipe and cathode liquid inlet pipe are both inserted into the interior of the cathode reaction zone; the anolyte outlet pipe and anolyte inlet pipe are both inserted into the interior of the anolyte reaction zone; and the pipes and pump bodies that come into contact with corrosive media are all made of fluoroplastics or titanium alloys.

3. The decoupled hydrazine-containing wastewater electrolysis hydrogen production system according to claim 1, characterized in that, The interior of the anode reaction zone is filled with an alkaline anode reaction solution, with the pH value controlled between 12 and 14.

4. The decoupled hydrazine-containing wastewater electrolysis hydrogen production system according to claim 1, characterized in that, The interior of the anolyte reaction zone is filled with an anolyte reaction solution containing any one of the following redox media: [Fe(CN)6] 3- / [Fe(CN)6] 4- [Ru(bpy)3] 2+ / [Ru(bpy)3] 3+ (VO2) + / (VO)2 + I – / I 3– An alkaline solution of 2,3-dihydroxyphenazine DHP or 2-amino-3-hydroxyphenazine.

5. The decoupled hydrazine-containing wastewater electrolysis hydrogen production system according to claim 4, characterized in that, The chemical reactor is equipped with a device for adding hydrazine and hydrazine-containing liquid. The corresponding catalyst includes any one of the following: platinum carbon catalyst, phosphating foamed nickel catalyst, cobalt nitrogen doped carbon nanosheets, Ru-VOx / Ni3S2, manganese cobalt sulfide catalyst, cobalt fluoride phosphide F-CoP, cobalt phosphide CoP, Pt@NiFc-MO, Mn@Ni3N-Co3N / NF, Ni3N-Co3NPNAs / NF, and CoFeNiCrMn / N.

6. The decoupled hydrazine-containing wastewater electrolysis hydrogen production system according to claim 1, characterized in that, The safety protection device includes a nitrogen charging unit, an electrolysis efficiency monitoring unit, and a multi-parameter monitoring module. The multi-parameter monitoring module is used to monitor the pressure, temperature, hydrazine concentration, and pH value of the medium in the reaction zone in real time. When the system parameters exceed the safety threshold, an early warning is triggered and emergency measures are taken.

7. The decoupled hydrazine-containing wastewater electrolysis hydrogen production system according to claim 1, characterized in that, A carbon felt electrode is disposed inside the anode plate containing the catalytic electrode, and a hydrogen evolution catalytic electrode is disposed inside the cathode plate containing the catalytic electrode.

8. A decoupled method for hydrogen production from hydrazine-containing wastewater by electrolysis, characterized in that, Includes the following steps: The process achieves low-energy electrolytic hydrogen production from hydrazine-containing wastewater through three steps: generating electricity using renewable energy devices, electrolytic hydrogen evolution, and chemical catalytic treatment of hydrazine-containing wastewater to produce nitrogen. A pair of redox media serves as charge transfer carriers circulating between the hydrogen evolution electrolysis cell and a separate chemical reactor. In the hydrogen evolution electrolysis cell, hydrogen evolution occurs at the cathode, while oxidation of the reduced media occurs at the anode. The resulting oxidized media is recycled to the chemical reactor, where it spontaneously reduces hydrazine under the action of a catalyst, releasing nitrogen. The overall process involves the electrolysis of hydrazine.

9. A decoupled method for electrolytic hydrogen production from hydrazine-containing wastewater, characterized in that, Includes the following steps: S1, construct a decoupled hydrazine-containing wastewater electrolysis hydrogen production system as described in any one of claims 1 to 7; S2, the decoupled hydrazine-containing wastewater electrolysis hydrogen production system operates as follows: When using the redox medium 2,3-dihydroxyphenazine (DHP), DHP is dissolved in an alkaline solution and oxidized to the oxidized state in the anode reaction zone. After complete reaction, it is pumped into the reaction buffer for storage through the anolyte outlet pipe and the anolyte outlet pump. The DHP in the reaction buffer is pumped into the chemical reactor through the reaction liquid inlet pipe and the reaction liquid inlet pump. Under the action of the catalyst, it reacts with hydrazine (N2H4) in the hydrazine-containing wastewater to the reduced state of DHPH2 and releases nitrogen gas. The generated nitrogen gas is collected in a nitrogen collection tank. The DHPH2 obtained from the reaction is returned to the reaction buffer through the reaction liquid outlet pipe. After the DHP in the reaction buffer and the chemical reactor is completely reacted to DHPH2, it is returned to the anode reaction zone through the anolyte inlet pipe. Electrolytic hydrogen reaction occurs in the cathode reaction zone. The cathode reaction solution, through the cathode solution outlet pipe, enters the cathode solution gas-liquid separator under the action of the cathode solution outlet pump. The hydrogen entrained in the cathode solution after the reaction will enter the hydrogen collection tank. The separated cathode solution returns to the cathode solution reaction zone through the cathode solution inlet pipe. During this process, the anion exchange membrane is used to separate the anode and cathode. It will migrate from the cathode to the anode through the anion exchange membrane, ensuring the overall electroneutrality of the decoupled hydrazine-containing wastewater hydrogen production system; at the same time, some of the water produced in the anode reaction zone will pass through the anion exchange membrane into the cathode reaction zone.

10. The decoupled method for hydrogen production from hydrazine-containing wastewater by electrolysis according to claim 9, characterized in that, It also includes the following steps: The decoupled hydrazine-containing wastewater electrolysis hydrogen production system operates in an intermittent mode and includes the following liquid addition process: anolyte is drawn from the reaction buffer through the anolyte inlet pipe and transported to the anode reaction zone to complete the liquid addition operation; hydrazine-containing wastewater is added to the chemical reactor, reacts fully with the DHP in the reaction buffer, and then transported to the reaction buffer through the reaction liquid outlet pipe. The liquid filling the cathode reaction zone includes seawater, mine water, or saline wastewater; the hydrazine-containing solution added to the chemical reactor includes hydrazine-containing wastewater.

11. The decoupled method for producing hydrogen from hydrazine-containing wastewater by electrolysis according to claim 9, characterized in that, The hydrogen evolution catalytic electrode disposed within the cathode plate containing the catalytic electrode includes any one of the following hydrogen evolution catalysts: platinum-nickel plating mesh, platinum-carbon catalyst, perovskite-based self-reconstructed catalyst Ca2CoRuO6, nickel-based carbon nanotube nickel hydroxide CNTs-Ni-Ni, copper-based catalyst DNTs-Cu, Mo5N6 nanosheet catalyst, Mn-NiO / Ni / NF catalyst, and NiCoP / NF catalyst.

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