A Separation and Decoupling Electrolytic Water Continuous Hydrogen Production System and Its Usage Method

Abstract

The present invention discloses a separation and decoupling water electrolysis continuous hydrogen production system and a method for using the same, which belongs to the field of hydrogen production and includes the following modules: a separation and decoupling water electrolysis reaction module; a hydrogen purification and collection module, including a condenser, a deoxidizer and a dryer connected to the crude hydrogen port and used to purify, refine and collect hydrogen in sequence; and a redox medium recycling and regeneration module, including a pyrolysis cell connected to the oxidized medium outlet and used to generate oxygen. The decoupling electrolysis chamber is used to achieve the temporal separation of the hydrogen evolution reaction and the oxygen evolution reaction. The hydrogen evolution reaction is prioritized, while the redox medium is used to efficiently capture and store oxygen free radicals. The decoupling cyclone is used to achieve rapid separation of the crude hydrogen and the redox medium, thereby completely decoupling the hydrogen generation and oxygen production processes at different reaction sites. Through the recycling and regeneration mechanism of the redox medium, the continuous and stable generation of hydrogen in a single reactor is achieved, and the product is of high purity and stable output, which is suitable for large-scale, long-term operation.

Description

Technical Field

[0001] The present invention relates to the field of hydrogen production by water electrolysis, and in particular to a separation and decoupling water electrolysis continuous hydrogen production system and a use method thereof. Background Art

[0002] In traditional electrolysis cells, the two half-reactions of water splitting—the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER)—are tightly coupled, making product separation difficult and, in turn, impacting process efficiency. Because the reaction rates of the OER and HER are interdependent, a high voltage (1.6–2.0 V) is typically required to drive both reactions simultaneously. Furthermore, the ion exchange membranes used for water electrolysis are expensive and have a significantly shortened operating life when used in non-pure water environments. They are particularly susceptible to degradation under actual industrial production environments, such as high temperature and high pressure. These factors collectively drive up the cost of water electrolysis. To overcome these issues, decoupled water electrolysis technology is becoming a research hotspot. By introducing redox mediators into the electrolysis process, this technology successfully separates the HER and OER in terms of reaction sequence and location, significantly improving reaction efficiency. It is considered a potential solution to overcome the bottlenecks of traditional water electrolysis technology.

[0003] By introducing a redox mediator, one half-reaction in the water splitting process can proceed spontaneously under thermal drive, converting it into a chemical reaction rather than an electrochemical reaction, thereby replacing part of the electrical energy consumption with more economical thermal energy. For example, in the OER process involving a redox mediator, the redox mediator is oxidized under electrochemical conditions without directly releasing oxygen. Subsequently, by regulating parameters such as temperature or catalyst, the redox mediator undergoes spontaneous chemical reduction and releases oxygen. This process replaces the OER overpotential of water splitting with the oxidation reaction overpotential of the redox mediator. Under the condition of selecting a suitable medium, this overpotential can be lower than the OER overpotential in traditional electrolytic cells.

[0004] For example, in some studies on decoupled seawater electrolysis, the overpotential of the oxidation reaction was significantly reduced through the single electron transfer reaction, while avoiding gas deposition and the formation of by-products. Studies have shown that at low voltage and high current (100 mA cm -2 , 1.57 V), maintaining system stability even in Cl⁻-saturated seawater electrolytes and potentially achieving zero chlorine emissions. The decoupled electrolysis strategy allows the voltage used in the water electrolysis process to be lower than the operating voltage of conventional electrolytic cells, thereby avoiding the formation of byproducts (such as chlorine and oxygen) in the electrolytic cell and reducing energy losses. Furthermore, through decoupling, the redox mediators can react spontaneously in the chemical reaction cell. Combined with industrial waste heat, this can further utilize waste energy and reduce dependence on external electricity, thereby achieving energy conservation and optimization.

[0005] Currently, decoupled water electrolysis devices rely on a step-by-step approach and a single electrode material, resulting in complex and inefficient redox mediator transfer and regeneration. Furthermore, if the medium reaches its upper limit of oxygen storage capacity and is not promptly transferred, oxygen can easily overflow and mix with hydrogen, increasing separation difficulty and safety risks. For example, Chinese Patent Publication No. CN 118308745 A discloses a step-by-step water electrolysis device based on a flow electrolysis cell; Chinese Patent Publication No. CN 118653161 A uses a V3O7 electrode as a redox mediator, achieving a reversible capacity of 270 mAh / g at a current density of 0.5 A / g. These patents all achieve decoupling of water electrolysis through a step-by-step approach, but this is limited to separation and decoupling of the reaction sequence and lacks a design for separation and decoupling of different reaction sites. This poses a high risk of hydrogen and oxygen mixing in actual operation. Furthermore, because half of the decoupling process is spent on reaction and the other half on regeneration, the overall utilization rate is low, limiting the reactor's operating efficiency. To address the issue of medium regeneration, Chinese Patent Publication No. CN114892180 B discloses a photovoltaic-thermal-driven thermochemical and electrolytic hydrogen production system, which uses solar energy to promote the oxygen evolution and regeneration of the redox medium. However, the overall efficiency of this step-by-step decoupled electrolysis water system is limited by the oxygen storage capacity of the redox medium. This makes it difficult to maintain stability during long-term operation and large-scale use, and the regeneration efficiency is also unsatisfactory.

[0006] In summary, in order to maximize the advantages of decoupled electrolysis water technology and improve the recycling efficiency of redox media, the field urgently needs to develop a system and method that can overcome the above-mentioned technical defects. Summary of the Invention

[0007] The purpose of the present invention is to provide a separation and decoupling water electrolysis continuous hydrogen production system and its use method in order to solve the above problems.

[0008] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0009] A separation and decoupling water electrolysis continuous hydrogen production system, including the following modules:

[0010] The separation and decoupling water electrolysis reaction module includes an insulating shell, a partition plate is provided near the bottom of the insulating shell, the chamber above the partition plate is a decoupling electrolysis chamber, and the lower part is an electrolyte replenishing chamber, and the partition plate is provided with multiple fluid distributors; a Johnson mesh ring sleeve is provided in the decoupling electrolysis chamber, the cathode electrode is provided in the Johnson mesh ring sleeve, and an annular inert anode electrode is provided on the outside; a decoupling cyclone is provided above the Johnson mesh ring sleeve, the upper part of the decoupling cyclone is connected to a crude hydrogen outlet, and the lower part is connected to an oxidized medium discharge outlet; the lower part of the decoupling electrolysis chamber is connected to a reduced medium inlet;

[0011] A hydrogen purification and collection module, comprising a condenser, a deoxidizer, and a dryer connected to the crude hydrogen port and sequentially purifying, refining, and collecting hydrogen;

[0012] The redox medium regeneration module includes a pyrolysis pool connected to the oxidized medium outlet and used to generate oxygen. The pyrolysis pool is connected to a cooling pool via a circulation pump. The cooling pool is connected to the reduced medium inlet. The temperature in the pyrolysis pool is maintained at T 1， 93℃≤T1≤97℃, peak-to-peak fluctuation ≤3℃.

[0013] Preferably, it also includes a separation and decoupling control module;

[0014] The separation and decoupling control module includes a current and voltage control unit connected to the cathode electrode and the annular inert anode electrode in the separation and decoupling water electrolysis reaction module, an oxygen concentration monitoring unit connected to the crude hydrogen outlet, and a temperature control unit connected to the constant temperature heater of the pyrolysis cell.

[0015] Preferably, the decoupling cyclone comprises an integrally formed columnar swirl chamber and a centrifugal separation chamber, wherein the columnar swirl chamber is arranged above the centrifugal separation chamber;

[0016] An inner sleeve is provided in the cylindrical swirl-generating chamber, a plurality of spiral guide vanes are arranged between the cylindrical swirl-generating chamber and the inner sleeve, and the inner sleeve is connected to a crude hydrogen outlet;

[0017] The centrifugal separation chamber is connected to an oxidized medium discharge port.

[0018] Preferably, a plurality of fixed connecting frames are provided on the top of the Johnson mesh ring sleeve along the circumferential direction, the annular inert anode electrode is connected to the fixed connecting frame, and the bottom of the Johnson mesh ring sleeve is connected to the partition plate;

[0019] The porosity of the Johnson mesh ring sleeve is 10% to 50%, and the annular gap diameter is 40% to 70% of the diameter of the electrolytic cell.

[0020] Preferably, the redox medium is bimetallic layered double hydroxide (LDH) particles;

[0021] The bimetallic layered double hydroxide (LDH) particles are Ni x Co 1-x (OH)2 particles, where 0 < x < 1, particle size D1, 0.5 mm ≤ D1 ≤ 2 mm, particles in electrolyte concentration C1, 5 wt% < C1 ≤ 10 wt%, particle porosity greater than 30%, and density ρ1, 2.0 g / cm 3 ≤ρ1≤3.0 g / cm 3 .

[0022] Preferably, the potential of the redox reaction of the bimetallic layered double hydroxide (LDH) particles in the electrolyte of the anode cell is lower than the potential of the oxygen evolution reaction, and the LDH particles are capable of storing oxygen free radicals.

[0023] Preferably, a spiral heat exchange tube is further provided inside the cooling pool in the redox medium circulation regeneration module, and the medium temperature is lowered to a temperature at which the self-discharge reaction is completely stopped by external cooling water.

[0024] The present invention also provides a method for using a separation and decoupling water electrolysis continuous hydrogen production system, which uses the above separation and decoupling water electrolysis continuous hydrogen production system, comprising the following steps:

[0025] (1) Decoupling the decoupling electrolysis chamber to produce crude hydrogen and oxidize the reduced medium at the same time, and the decoupling cyclone separates the crude hydrogen and the oxidized medium;

[0026] (2) using the redox medium recycling module to heat and reduce the oxidized medium to generate oxygen, and at the same time, the recycled reduced medium is returned to the decoupling electrolysis chamber;

[0027] (3) Purify, refine and collect the crude hydrogen using a condenser, deoxidizer and dryer;

[0028] (4) The separation and decoupling control module is used to dynamically control the operating parameters to achieve the current, voltage, oxygen concentration and temperature joint control of the separation and decoupling water electrolysis continuous hydrogen production system.

[0029] Furthermore, the operating parameters dynamically controlled by the separation and decoupling control module include current density, voltage, pyrolysis cell temperature, and redox medium circulation flow rate; the current density is controlled by an electrochemical workstation, and the current density of the separation and decoupling water electrolysis reaction module is ≥100 mA / cm when it is operating normally. 2 The safety threshold when oxygen exceeds the limit is ≤50 mA / cm 2 ;

[0030] The current and voltage control unit uses a three-electrode potential control system, with a reference electrode added inside the anode electrode. The polarization potential between the anode and the reference electrode is monitored in real time by a potentiostat; the polarization potential always meets the selective oxidation threshold setting, and the upper limit of the selective oxidation threshold setting is lower than the oxygen evolution reaction starting potential ΔU, ΔU ≥ 0.3V, and the lower limit is higher than 1.1 times the potential required for complete oxidation of the redox medium.

[0031] In summary, the beneficial effects of the present invention are:

[0032] 1. Sequential separation and decoupling of reactions: Decoupling the electrolytic chamber allows for the sequential separation of hydrogen evolution reaction and oxygen evolution reaction. The hydrogen evolution reaction is prioritized, while the redox mediator is used to efficiently capture and store oxygen free radicals.

[0033] 2. Separation and decoupling of reaction sites: The decoupling cyclone is used to quickly separate the crude hydrogen and the redox medium, thereby completely decoupling the hydrogen generation and oxygen production processes at different reaction sites.

[0034] 3. Through the recycling regeneration mechanism of redox media, continuous and stable generation of hydrogen is achieved in a single reactor, with high-purity and stable output of products, which is suitable for large-scale and long-term operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 This is a schematic diagram of the process flow of the separation and decoupling water electrolysis continuous hydrogen production system of the present invention;

[0037] Figure 2 This is a schematic structural diagram of the separation and decoupling water electrolysis reaction module of the present invention;

[0038] Figure 3 It is a schematic diagram of the three-dimensional structure of the Johnson mesh ring sleeve of the present invention;

[0039] Figure 4 The Ni 0.9 Co 0.1 Galvanostatic charging curves of (OH)2 anode in 5M KOH aqueous electrolyte;

[0040] Figure 5 The present invention adopts Ni 0.9 Co 0.1 Cyclic voltammogram of (OH)2 as redox mediator in 5M KOH aqueous solution.

[0041] The following are the descriptions of the reference numerals:

[0042] 1. Separation and decoupling of water electrolysis reaction module; 101. Insulation shell; 102. Electrolyte replenishing chamber; 102a. Electrolyte inlet; 103. Partition plate; 104. Fluid distributor; 105. Decoupling electrolysis chamber; 106. Johnson mesh ring sleeve; 107. Cathode electrode; 108. Anode electrode; 109. Reducing medium inlet; 110. Oxidizing medium outlet; 111. Cathode wire protective sleeve; 112. Decoupling cyclone; 112a. Columnar swirl chamber; 112b. Centrifugal separation chamber; 112c. Spiral guide vane; 112d. Inner sleeve ; 113. Crude hydrogen outlet; 114. Top cover; 115. Air pressure balancing valve; 116. Cathode electrode interface; 117. Anode electrode interface; 118. Fixed connecting frame; 119. Anode wire protective cover; 2. Hydrogen purification and collection module; 201. Condenser; 202. Deoxidizer; 203. Dryer; 3. Redox medium recycling and regeneration module; 301. Cooling tank; 302. Circulation pump; 303. Pyrolysis tank; 4. Separation and decoupling control module; 401. Current and voltage control unit; 402. Oxygen concentration monitoring unit; 403. Temperature control unit. DETAILED DESCRIPTION

[0043] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0044] See also Figure 1-Figure 5 As shown, the present invention provides a separation and decoupling water electrolysis continuous hydrogen production system, including a separation and decoupling water electrolysis reaction module 1, a hydrogen purification and collection module 2, a redox medium recycling module 3, and a separation and decoupling control module 4. During normal operation of the above system, the separation and decoupling water electrolysis reaction module 1 generates crude hydrogen and an oxidized redox medium. The oxidized medium enters the redox medium recycling module 3, is heated to release oxygen, and is reduced and regenerated before returning to the separation and decoupling water electrolysis reaction module 1. The crude hydrogen is purified and collected by the hydrogen purification and collection module 2. The entire system dynamically controls operating parameters through the separation and decoupling control module 4 to achieve joint control of current, voltage, oxygen concentration, and temperature.

[0045] Among them, reference Figure 2As shown, the separation and decoupling water electrolysis reaction module 1 includes an insulating shell 101, and a partition plate 103 is provided near the bottom of the insulating shell 101. The chamber above the partition plate 103 is a decoupling electrolysis chamber 105, and the electrolyte replenishing chamber 102 is provided below. The partition plate 103 is provided with multiple fluid distributors 104; a Johnson mesh ring sleeve 106 is provided in the decoupling electrolysis chamber 105, and a cathode electrode 107 is provided in the Johnson mesh ring sleeve 106, and an annular inert anode electrode 108 is provided on the outside. A top cover 114 is provided on the top of the insulating shell 101, and a cathode wire protection sleeve 111 is provided on the guide outside of the cathode electrode 107, and the cathode electrode 107 is connected to the cathode electrode interface 116 on the top cover 114. An anode wire protection sleeve 119 is provided on the outside of the wire of the annular inert anode electrode 108, and the anode electrode 108 is connected to the anode electrode interface 117 on the top cover 114. The top cover 114 is also provided with an air pressure balance valve 115. A plurality of fixed connecting brackets 118 are circumferentially arranged above the Johnson mesh ring sleeve 106. The annular inert anode electrode 108 is connected to these fixed connecting brackets 118. The bottom of the Johnson mesh ring sleeve 106 is connected to the partition plate 103. A decoupling cyclone 112 is provided above the Johnson mesh ring sleeve 106. The top of the decoupling cyclone 112 is connected to a crude hydrogen outlet 113 and the bottom is connected to an oxidized medium outlet 110. The bottom of the decoupling electrolysis chamber 105 is connected to a reduced medium inlet 109, and the electrolyte replenishment chamber 102 is connected to an electrolyte inlet 102a. Electrolyte enters the decoupling electrolysis chamber 105 through the electrolyte inlet 102a at the bottom of the device. Before the device is operated, a sufficient amount of electrolyte is introduced from the bottom. During operation, the electrolyte is replenished by a replenishment signal and flows through the fluid distributor 104 on the bottom partition plate 103 to fluidize the redox medium particles and evenly distribute them in the electrolytic cell. The fluid distributor 104 includes a mesh shell, which connects the decoupling electrolysis chamber 105 with the electrolyte replenishing chamber 102 through a connecting pipe, and can replenish the electrolyte for the decoupling electrolysis chamber 105.

[0046] Combined with reference Figure 1 、 Figure 2 and Figure 3 The cathode electrode 107, the annular inert anode electrode 108, and the Johnson mesh ring sleeve 106 together constitute the decoupling electrolysis chamber 105. To prevent the redox medium from directly shuttling between the cathode electrode 107 and the anode electrode 108, a Johnson mesh ring sleeve 106 composed of a Johnson mesh is provided between the electrodes. The Johnson mesh ring sleeve 106 is fixedly mounted on the partition plate 103. The porosity of the Johnson mesh ring sleeve 106 is 10% to 50%, and the annular gap diameter is 40% to 70% of the diameter of the electrolytic cell. As a preferred embodiment of this case, the porosity of the Johnson mesh ring sleeve 106 is 30%, and the annular gap diameter is 55% of the diameter of the electrolytic cell.

[0047] The cathode electrode 107 is located within the Johnson mesh ring sleeve 106. In this embodiment, the cathode electrode 107 is a stainless steel mesh electrode coated with nickel platinum and coated with a hydrogen evolution reaction (HER) catalyst to minimize the HER reaction barrier. The annular inert anode electrode 108 is a glassy carbon electrode connected to the positive terminal of the power supply and is not coated with the catalyst. A wire protection tube is provided at the junction of the anode electrode 108 and the cathode electrode 107, connecting them to the top electrode interface. During the electrolysis process, hydrogen is generated through an electrochemical reaction at the cathode electrode 107. The redox mediator particles uniformly dispersed in the electrolyte between the annular inert anode electrode 108 and the Johnson mesh ring sleeve 106 effectively store oxygen free radicals through redox reactions. This design decouples the two half-reactions of water splitting, separating the generation of oxygen and hydrogen, preventing simultaneous gas mixing. The fluidized redox mediator design also optimizes oxygen storage capacity, improving the overall stability and efficiency of the reaction system.

[0048] The hydrogen purification and collection module 2 includes a condenser 201, a deoxidizer 202 and a dryer 203 connected to the crude hydrogen port and used to purify, refine and collect hydrogen in sequence;

[0049] The redox medium regeneration module 3 includes a pyrolysis cell 303 connected to the oxidized medium outlet 110 and used to generate oxygen. The pyrolysis cell 303 is connected to a cooling cell 301 via a circulation pump 302, and the cooling cell 301 is connected to the reduced medium inlet 109. The pyrolysis cell 303 is equipped with an axial stirrer, a thermostatic heater, and a thermometer. The thermostatic heater maintains the temperature within the pyrolysis cell 303 at T1, 93°C ≤ T1 ≤ 97°C, with a peak-to-peak fluctuation of ≤3°C.

[0050] Furthermore, a spiral heat exchange tube is provided inside the cooling pool 301 in the redox medium recycling module 3 to reduce the medium temperature to a temperature at which the self-discharge reaction is completely stopped, i.e., below 50° C., by external cooling water.

[0051] The separation and decoupling control module 4 includes a current and voltage control unit 401 connected to the cathode electrode 107 and the annular inert anode electrode 108 in the separation and decoupling water electrolysis reaction module 1, an oxygen concentration monitoring unit 402 connected to the crude hydrogen outlet 113, and a temperature control unit 403 connected to the constant temperature heater of the pyrolysis cell.

[0052] As a preferred embodiment, the decoupling cyclone 112 includes an integrally formed columnar vortex-generating chamber 112a and a centrifugal separation chamber 112b, wherein the columnar vortex-generating chamber 112a is arranged above the centrifugal separation chamber 112b; an inner sleeve 112d is provided in the columnar vortex-generating chamber 112a, and a plurality of spiral guide vanes 112c are arranged between the columnar vortex-generating chamber 112a and the inner sleeve 112d, and the inner sleeve 112d is connected to the crude hydrogen outlet 113; the centrifugal separation chamber 112b is connected to the oxidized medium discharge outlet 110. During operation, the electrolyte continuously enters the electrolyte replenishing chamber 102 from the lower electrolyte inlet 102a, and then the three-phase mixed fluid composed of gaseous hydrogen, liquid electrolyte, and solid redox medium enters the centrifugal separation chamber 112b through the opening at the upper end of the columnar vortex chamber 112a. The columnar vortex chamber 112a is provided with a number of spiral guide vanes 112c for creating a vortex to accelerate the separation of hydrogen microbubbles. With the guidance of the spiral guide vanes 112c, the electrolyte forms a stable vortex inside the decoupling cyclone 112. Under the centrifugal force of the cyclone field, hydrogen and a small amount of electrolyte are discharged from the overflow port of the cyclone; at the same time, the electrolyte containing the redox medium storing oxygen free radicals is discharged from the bottom flow port of the cyclone and enters the redox medium recycling module 3.

[0053] As a preferred embodiment, the redox medium is a bimetallic layered double hydroxide (LDH) particle; the bimetallic layered double hydroxide (LDH) particle is Ni x Co 1-x (OH)2 particles, where 0 < x < 1, particle size D1, 0.5 mm ≤ D1 ≤ 2 mm, particles in electrolyte concentration C1, 5 wt% < C1 ≤ 10 wt%, particle porosity greater than 30%, and density ρ1, 2.0 g / cm 3 ≤ρ1≤3.0 g / cm 3 The bimetallic layered double hydroxide (LDH) particles undergo a redox reaction in the electrolyte of the anode cell at a potential lower than the oxygen evolution reaction potential, enabling the storage of oxygen free radicals. The redox medium is prepared by coating a conductive substrate with high-purity ultrafine nickel powder using an electrodeposition method.

[0054] In the embodiment of this case, the redox medium is selected to be Ni 0.9 Co 0.1 (OH)2 (hereinafter referred to as "medium"), the electrolyte is 5M KOH aqueous solution (hereinafter referred to as "electrolyte"), the principle of decoupled water electrolysis is as follows: the micron-sized redox medium is uniformly dispersed in the electrolyte of the anode cell and undergoes redox reaction between the anode inert solid auxiliary electrode and the Johnson mesh ring sleeve. The overall process of the reversible redox reaction of the redox medium is: .

[0055]

[0056] The medium is evenly dispersed in the alkaline electrolyte, acting as an electronically coupled hydroxide buffer, mediating the exchange of hydroxide ions between the cathode electrode and the auxiliary electrode. At the cathode of the electrolytic cell, the HER reduction reaction (Rxn.2) occurs, and the generated hydroxide ions are transferred to the redox medium through the electrolyte. The medium then undergoes a forward oxidation reaction (Rxn.1 forward) and absorbs the hydroxide ions generated by the HER. The hydroxide ions are transferred to the medium through the electrolyte and then absorbed by the Ni 0.9 Co 0.1 (OH)2 is absorbed by oxidation reaction and converted into Ni 0.9 Co 0.1 OOH:

[0057]

[0058]

[0059] is the standard hydrogen electrode potential, is the overpotential of the equation. As shown in Rxn. 1, the test potential of the mediator redox reaction is higher than the standard potential of OER (1.23 V RHE ). Therefore, the oxidized Ni 0.9 Co 0.1 OOH is reduced to Ni 0.9 Co 0.1 During the process of (OH)2, oxygen can be produced by the spontaneous reduction of oxidized water. In the pyrolysis cell, the oxidized medium at high temperature (95°C in the example) follows the Arrhenius equation (Eq. 1) for accelerated self-discharge: in: is the reaction rate constant; Pre-exponential factor or frequency factor; is the activation energy; is the gas constant; is the temperature in Kelvin.

[0060] The self-discharge reaction is : Further, before the hydrogen production system works, it should be ensured that the decoupling electrolysis chamber 105 of the separation and decoupling water electrolysis reaction module 1 is filled with enough electrolytes, and the medium is evenly dispersed in the anode cell. After the electric current is connected, an oxidation reaction occurs on the surface of the medium, but oxygen is not produced. At this moment, the electrolysis process occurring in the separation and decoupling water electrolysis reaction module 1 is mainly used to produce a single hydrogen. The hydrogen generated is collected by the external gas collecting device of the thick hydrogen outlet 113.

[0061] Furthermore, before starting the circulation system, it should be ensured that the electrolytic cell has been running for a period of time to ensure that sufficient medium has been oxidized to an oxidized state. When the circulation system is working, the bottom electrolyte inlet continues to provide electrolyte and the circulation pump 302 is started. The electrolyte containing the oxidized medium is transported to the pyrolysis cell 303 through the redox medium outlet, and a reduction reaction is carried out in the pyrolysis cell 303, thereby producing a single oxygen. The constant temperature heater in the pyrolysis cell is kept in working condition to ensure the constant pyrolysis temperature. The generated oxygen is collected by a gas collection device external to the pyrolysis cell.

[0062] The specific experimental cases are as follows:

[0063] The separation and decoupling water electrolysis continuous hydrogen production system provided by the present invention is applied to the decoupling water electrolysis experiment, and the present invention is further illustrated by the experimental case. The cathode electrode in the electrolytic cell is a stainless steel mesh electrode plated with a nickel-platinum coating, and the redox medium is a micron-sized Ni prepared by electrodeposition of high-purity ultrafine nickel powder on a conductive substrate. 0.9 Co 0.1 (OH)2 particles, the electrolyte is 5M KOH aqueous solution.

[0064] Figure 5 The results show that at ambient temperature (25°C), Ni 0.9 Co 0.1 The cyclic voltammetry test of the working electrode of (OH)2 particles in 5M KOH aqueous solution showed a peak at 1.4V. RHE The redox wave is centered on the electrode. The figure shows the steady-state current-potential diagram of the same electrode and the same electrolyte at ambient temperature (○) and 95°C (△). At ambient temperature, the redox potential of the electrode loaded with the medium (1.4V RHE ) Steady-state OER current density is less than 1 mA / cm 2 Therefore, although the chemical reduction of the redox mediator ( ) is a spontaneous reaction, but occurs very slowly at ambient temperature. However, the reaction rate can be significantly increased by increasing the temperature, e.g. Figure 5 As shown by the curve (△) in .

[0065] Figure 4 It shows that at room temperature, Ni 0.9 Co 0.1 The constant current charging curve of (OH)2 anode in 5M KOH aqueous solution electrolyte. It can be observed from the figure that Ni 0.9 Co 0.1 After the (OH)2 electrode reaches a certain charge level (about 50% under the working condition shown in the figure), its anode potential increases from 1.4 V to RHERapidly increases to 1.5 V RHE Around this point, the charging potential plateau gradually shifts toward the OER plateau, and the oxygen storage anode begins to evolve into an overcharged anode. This situation must be avoided in the present invention. To ensure that the HER in the electrolytic cell stops before the medium overcharges, the following measures must be taken: setting a potential limit on the charging anode, a charge limit, a voltage limit (between the anode and cathode), or achieving effective control by monitoring the dissolved oxygen concentration.

[0066] The experimental results show that hydrogen is generated through an electrochemical reaction, and its generation rate is directly controlled by the applied current density. Oxygen, on the other hand, is generated through a spontaneous chemical reaction under heating conditions, and its production rate cannot be directly controlled by current density. However, by adjusting the temperature, the anode regeneration rate can be controlled, thereby suppressing the initial oxygen generation that occurs near ambient temperature and accelerating the secondary oxygen generation at high temperatures (95°C). Therefore, temperature is a key control parameter in this decoupled water electrolysis system, capable of slowing or accelerating oxygen generation in the electrolytic and pyrolytic cells, respectively, similar to a temperature-swinging absorption process. Even at room temperature, oxygen may still be generated during the oxidation of the medium, especially when the oxidation reaction enters the peroxidation phase. However, through external monitoring, this process can be effectively controlled, thereby slowing the rate of oxygen generation.

[0067] The present invention also provides a method for using a separation and decoupling water electrolysis continuous hydrogen production system, which uses the above separation and decoupling water electrolysis continuous hydrogen production system, comprising the following steps:

[0068] (1) Decoupling the decoupling electrolysis chamber 105 to generate crude hydrogen and oxidize the reduced medium at the same time, and the decoupling cyclone 112 separates the crude hydrogen from the oxidized medium;

[0069] (2) using the redox medium recycling module 3 to heat and reduce the oxidized medium to generate oxygen, and at the same time, the recycled reduced medium is returned to the decoupling electrolysis chamber 105;

[0070] (3) Purifying, refining and collecting the crude hydrogen using the condenser 201, the deoxidizer 202 and the dryer 203;

[0071] (4) The separation and decoupling control module 4 is used to dynamically control the operating parameters to achieve the current, voltage, oxygen concentration and temperature joint control of the separation and decoupling water electrolysis continuous hydrogen production system.

[0072] Furthermore, the operating parameters dynamically controlled by the separation and decoupling control module 4 include current density, voltage, pyrolysis cell temperature, and redox medium circulation flow rate; the current density is controlled by the electrochemical workstation, and the current density of the separation and decoupling water electrolysis reaction module 1 is ≥100 mA / cm when it is operating normally. 2The safety threshold when oxygen exceeds the limit is ≤50 mA / cm 2 ;

[0073] The current and voltage control unit 401 uses a three-electrode potential control system, with a reference electrode added inside the anode electrode 108. The polarization potential between the anode and the reference electrode is monitored in real time by a potentiostat; the polarization potential always meets the selective oxidation threshold setting, and the upper limit of the selective oxidation threshold setting is lower than the oxygen evolution reaction starting potential △U, △U ≥ 0.3 V, and the lower limit is higher than 1.1 times the potential required for complete oxidation of the redox medium.

[0074] Furthermore, potential and voltage regulation: The anode polarization potential is monitored in real time using a potentiometer to ensure that the polarization potential always meets the oxidation threshold setting. The upper limit of the oxidation threshold must be at least 0.2V below the onset potential of the oxygen evolution reaction of the redox medium (calibrated by pre-testing the system using linear sweep voltammetry) to inhibit the oxygen evolution side reaction; the lower limit must be set to 0.2V above the complete oxidation potential of the redox medium (calibrated by pre-testing the system using linear sweep voltammetry) to ensure sufficient reaction progress.

[0075] Voltage adaptive compensation: If the oxygen concentration monitoring unit 402 (oxygen concentration sensor) connected to the crude hydrogen outlet 113 detects that the oxygen concentration exceeds the limit (>0.1%), the system automatically reduces the electrolytic cell voltage to a safe range (≤1.8 V) and immediately cuts off the circulation pump 302.

[0076] Pyrolysis cell temperature control: The pyrolysis cell temperature is stabilized at 95±2°C using a constant temperature heater (resistance heating device). The temperature sensor provides real-time feedback to the controller. If the temperature exceeds the threshold, the heating power is cut off and a shutdown signal is sent to the electrolytic cell.

[0077] Interlocked control of the medium circulation rate: A flow sensor monitors the circulation flow rate of the redox medium and controls the redox medium charge. During normal system operation, the circulation flow rate is maintained at a constant 30 L / min. When the electrolytic cell's hydrogen production rate drops to 80% of the limit, the circulation flow rate is reduced to 10 L / min, and the refill pump is automatically triggered to inject backup medium. The limit is calibrated by a pre-test system. The oxygen concentration monitoring unit 402 at the crude hydrogen outlet 113 monitors oxygen concentration to prevent overcharging of the redox medium. If the monitored oxygen concentration exceeds 0.02%, the circulation flow rate is increased to 30 L / min. If the oxygen concentration exceeds the limit (>0.1%), the system immediately shuts off the circulation pump 302.

[0078] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A separation and decoupling water electrolysis continuous hydrogen production system, characterized in that: Includes the following modules: The separation and decoupling water electrolysis reaction module includes an insulating shell, a partition plate is provided near the bottom of the insulating shell, the chamber above the partition plate is a decoupling electrolysis chamber, and the lower part is an electrolyte replenishing chamber, and the partition plate is provided with multiple fluid distributors; a Johnson mesh ring sleeve is provided in the decoupling electrolysis chamber, the cathode electrode is provided in the Johnson mesh ring sleeve, and an annular inert anode electrode is provided on the outside; a decoupling cyclone is provided above the Johnson mesh ring sleeve, the upper part of the decoupling cyclone is connected to a crude hydrogen outlet, and the lower part is connected to an oxidized medium discharge outlet; the lower part of the decoupling electrolysis chamber is connected to a reduced medium inlet; A hydrogen purification and collection module, comprising a condenser, a deoxidizer, and a dryer connected to the crude hydrogen port and sequentially purifying, refining, and collecting hydrogen; The redox medium regeneration module includes a pyrolysis pool connected to the oxidized medium outlet and used to generate oxygen. The pyrolysis pool is connected to a cooling pool via a circulation pump. The cooling pool is connected to the reduced medium inlet. The temperature in the pyrolysis pool is maintained at T 1， 93℃≤T1≤97℃, peak-to-peak fluctuation ≤3℃; The porosity of the Johnson mesh ring sleeve is 10% to 50%, and the annular gap diameter is 40% to 70% of the electrolytic cell diameter; The redox medium is a bimetallic layered double hydroxide particle; the bimetallic layered double hydroxide particle is Ni x Co 1-x (OH)2 particles, where 0 < x < 1, particle size D1, 0.5 mm ≤ D1 ≤ 2 mm, particles in electrolyte concentration C1, 5 wt% < C1 ≤ 10 wt%, particle porosity greater than 30%, and density ρ1, 2.0 g / cm 3 ≤ρ1≤3.0 g / cm 3 ; The potential of the bimetallic layered double hydroxide particles in the electrolyte of the anode cell during the redox reaction is lower than the potential of the oxygen evolution reaction, and the particles can store oxygen free radicals.

2. A separation and decoupling water electrolysis continuous hydrogen production system according to claim 1, characterized in that: It also includes a separation and decoupling control module; The separation and decoupling control module includes a current and voltage control unit connected to the cathode electrode and the annular inert anode electrode in the separation and decoupling water electrolysis reaction module, an oxygen concentration monitoring unit connected to the crude hydrogen outlet, and a temperature control unit connected to the constant temperature heater of the pyrolysis cell.

3. A separation and decoupling water electrolysis continuous hydrogen production system according to claim 1, characterized in that: The decoupling cyclone comprises an integrally formed cylindrical swirl chamber and a centrifugal separation chamber, wherein the cylindrical swirl chamber is arranged above the centrifugal separation chamber; An inner sleeve is provided in the cylindrical swirl-generating chamber, a plurality of spiral guide vanes are arranged between the cylindrical swirl-generating chamber and the inner sleeve, and the inner sleeve is connected to a crude hydrogen outlet; The centrifugal separation chamber is connected to an oxidized medium discharge port.

4. A separation and decoupling water electrolysis continuous hydrogen production system according to claim 1, characterized in that: A plurality of fixed connection frames are provided above the Johnson mesh ring sleeve along the circumferential direction, the annular inert anode electrode is connected to the fixed connection frame, and the bottom of the Johnson mesh ring sleeve is connected to the partition plate.

5. A separation and decoupling water electrolysis continuous hydrogen production system according to claim 1, characterized in that: A spiral heat exchange tube is further provided inside the cooling pool of the redox medium circulation regeneration module, and the medium temperature is lowered to a temperature at which the self-discharge reaction is completely stopped by external cooling water.

6. A method for using a separation and decoupling water electrolysis continuous hydrogen production system, characterized in that: The separation and decoupling water electrolysis continuous hydrogen production system according to claim 2 comprises the following steps: (1) Decoupling the decoupling electrolysis chamber to produce crude hydrogen and oxidize the reduced medium at the same time, and the decoupling cyclone separates the crude hydrogen and the oxidized medium; (2) using the redox medium recycling module to heat and reduce the oxidized medium to generate oxygen, and at the same time, the recycled reduced medium is returned to the decoupling electrolysis chamber; (3) Purify, refine and collect the crude hydrogen using a condenser, deoxidizer and dryer; (4) The separation and decoupling control module is used to dynamically control the operating parameters to achieve the current, voltage, oxygen concentration and temperature joint control of the separation and decoupling water electrolysis continuous hydrogen production system.

7. The method for using the separation and decoupling water electrolysis continuous hydrogen production system according to claim 6, characterized in that: The operating parameters dynamically controlled by the separation and decoupling control module include current density, voltage, pyrolysis cell temperature, and redox medium circulation flow rate; the current density is controlled by an electrochemical workstation. When the separation and decoupling water electrolysis reaction module operates normally, the current density is ≥100 mA / cm2, and the safety threshold when oxygen exceeds the limit is ≤50 mA / cm2.

8. The method for using the separation and decoupling water electrolysis continuous hydrogen production system according to claim 7, characterized in that: The current and voltage control unit uses a three-electrode potential control system, with a reference electrode added inside the anode electrode. The polarization potential between the anode and the reference electrode is monitored in real time by a potentiostat; the polarization potential always meets the selective oxidation threshold setting, and the upper limit of the selective oxidation threshold setting is lower than the onset potential of the oxygen evolution reaction by ΔU, ΔU ≥ 0.3 V, and the lower limit is higher than 1.1 times the potential required for complete oxidation of the redox medium.

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