Separation decoupling electrolysis water continuous hydrogen production system and use method thereof

Abstract

The invention discloses a separation and decoupling electrolysis water continuous hydrogen production system and a use method thereof, and belongs to the field of hydrogen production. The hydrogen purification and collection module comprises a condenser, a deaerator and a dryer which are connected with the crude hydrogen port and are used for purifying, purifying and collecting hydrogen in sequence; and the redox medium cyclic regeneration module comprises a pyrolysis tank which is connected with the oxidation state medium outlet and is used for generating oxygen. And the time sequence separation of the hydrogen evolution reaction and the oxygen evolution reaction is realized by decoupling the electrolysis chamber. Hydrogen evolution reaction is preferentially carried out, and meanwhile, oxygen free radicals are efficiently captured and stored by using a redox medium. Rapid separation of crude hydrogen and an oxidation-reduction medium is realized through the decoupling cyclone, so that hydrogen generation and oxygen production processes are completely decoupled in different reaction places. Through a cyclic regeneration mechanism of an oxidation-reduction medium, continuous and stable generation of hydrogen in a single reactor, high purity and stable output of a product are realized, and the method is suitable for large-scale and long-period operation.

Description

Technical Field

[0001] The 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 decomposition, the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), are tightly coupled, which makes it difficult to separate the products, thus affecting the process efficiency. Since the reaction rates of OER and HER are interdependent, a high voltage (1.6~2.0V) is usually required to drive these two reactions simultaneously. In addition, the ion exchange membranes used for water electrolysis are expensive, and their operating life is significantly shortened when used in non-pure water environments. In particular, they are prone to degradation in actual industrial production environments such as high temperature and high pressure. These factors have jointly pushed up the cost of water electrolysis. To overcome these problems, decoupled water electrolysis technology is gradually becoming a research hotspot. By introducing redox mediators into the electrolysis process, this technology successfully achieves the separation of HER and OER in terms of reaction timing and reaction site, thereby greatly improving the reaction efficiency. It is regarded as a potential solution to break through the bottleneck of traditional water electrolysis technology.

[0003] By introducing a redox mediator, one of the half reactions 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 a traditional electrolytic cell.

[0004] For example, in some studies on decoupled electrolysis of seawater, 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), the stability of the system can be maintained even in Cl⁻-saturated seawater electrolyte, and it is possible to achieve zero chlorine emissions. The strategy of decoupled electrolysis makes the voltage used in the water electrolysis process lower than the operating voltage of conventional electrolytic cells, thereby avoiding the generation of by-products (such as chlorine, oxygen) in the electrolytic cell and reducing energy losses. In addition, through decoupling, the redox mediator can react spontaneously in the chemical reaction cell, and combined with industrial waste heat, waste energy can be further utilized to reduce dependence on external electricity, thereby achieving energy conservation and optimization.

[0005] At present, the decoupled water electrolysis device relies on a step-by-step method and a single electrode material, which leads to complex and inefficient redox medium transfer and regeneration. And when the medium reaches the upper limit of oxygen storage, if it is not transferred in time, it is easy to overflow oxygen and mix with hydrogen, increasing the difficulty of separation and safety risks. For example, Chinese Patent Publication No. CN 118308745 A discloses a step-by-step water electrolysis device based on a flow electrolytic cell; Chinese Patent Publication No. CN 118653161 A uses a V3O7 electrode as a redox medium to achieve a reversible capacity of 270 mAh / g at a current density of 0.5 A / g. These patents all achieve the decoupling of water electrolysis through a step-by-step method, but are limited to separation and decoupling in reaction timing, lack separation and decoupling design in different reaction sites, and have a high risk of hydrogen and oxygen mixing in actual operation. In addition, since half of the decoupling process is used for reaction and the other half is used for regeneration, the overall utilization rate is low, and the operating efficiency of the reactor is also limited. In order to solve the problem of medium regeneration, Chinese patent publication number CN114892180 B discloses a photovoltaic-thermal-driven thermochemical and electrolytic coupled hydrogen production system, which promotes the oxygen release and regeneration of the redox medium through solar energy. However, the overall efficiency of this type of step-by-step decoupled electrolytic water system is limited by the oxygen storage capacity of the redox medium, and it is difficult to maintain stability in long-term operation and large-scale use, and the regeneration efficiency is also not ideal.

[0006] In summary, in order to maximize the advantages of decoupled water electrolysis technology and improve the recycling efficiency of redox media, the art 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 a method of using the system in order to solve the above problems.

[0008] The present invention achieves the above-mentioned purpose through the following technical solutions: A separation and decoupling water electrolysis continuous hydrogen production system, comprising the following modules: A separation and decoupling water electrolysis reaction module comprises an insulating shell, wherein a partition plate is provided near the lower part 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 a plurality of fluid distributors are provided on the partition plate; a Johnson mesh ring sleeve is provided in the decoupling electrolysis chamber, wherein a 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, wherein 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; and the lower part of the decoupling electrolysis chamber is connected to a reduced medium inlet; A hydrogen purification and collection module, including a condenser, a deoxidizer and a dryer connected to the crude hydrogen port and sequentially purifying, refining and collecting hydrogen; The redox medium circulation 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 through a circulation pump, the cooling pool is connected to the reduced medium inlet, and the temperature in the pyrolysis pool is maintained at T 1， 93℃≤T1≤97℃, fluctuation peak-to-peak value ≤3℃.

[0009] Preferably, 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.

[0010] Preferably, the decoupling cyclone comprises an integrally formed columnar cyclone-generating chamber and a centrifugal separation chamber, wherein the columnar cyclone-generating chamber is arranged above the centrifugal separation chamber; An inner sleeve is arranged in the columnar swirl-generating chamber, a plurality of spiral guide vanes are arranged between the columnar swirl-generating chamber and the inner sleeve, and the inner sleeve is connected to a crude hydrogen outlet; The centrifugal separation chamber is connected with an oxidized medium discharge port.

[0011] Preferably, 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; 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.

[0012] Preferably, the redox medium is bimetallic layered double hydroxide (LDH) particles; 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 .

[0013] Preferably, the bimetallic layered double hydroxide (LDH) particles undergo a redox reaction at a potential lower than an oxygen evolution reaction potential in the electrolyte of the anode cell, and are capable of storing oxygen free radicals.

[0014] 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.

[0015] The present invention also provides a method for using a separation and decoupling water electrolysis continuous hydrogen production system, using the above separation and decoupling water electrolysis continuous hydrogen production system, comprising 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) Purifying, refining and collecting the crude hydrogen using a condenser, a deoxidizer and a dryer; (4) Using the separation and decoupling control module to dynamically control the operating parameters, the current, voltage, oxygen concentration and temperature joint control of the separation and decoupling water electrolysis continuous hydrogen production system is achieved.

[0016] Furthermore, the operating parameters dynamically regulated 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 ; The current and voltage control unit uses a three-electrode potential control system, a reference electrode is added inside the anode electrode, and the polarization potential between the anode and the reference electrode is monitored in real time by a constant potential instrument; the polarization potential always meets the selective oxidation threshold setting, the upper limit of the selective oxidation threshold setting is lower than the oxygen evolution reaction starting potential △U, △U ≥ 0.3V, and the lower limit is higher than 1.1 times the potential required for complete oxidation of the redox medium.

[0017] In summary, the beneficial effects of the present invention are: 1. Separation and decoupling of reaction timing: The timing of hydrogen evolution reaction and oxygen evolution reaction is separated by decoupling the electrolytic chamber. Hydrogen evolution reaction is prioritized, while redox mediators are used to efficiently capture and store oxygen free radicals.

[0018] 2. Separation and decoupling of reaction sites: The decoupling cyclone is used to achieve rapid separation of crude hydrogen and redox media, thereby completely decoupling the hydrogen generation and oxygen production processes at different reaction sites.

[0019] 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

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0021] Figure 1 It is a schematic diagram of the process flow of the separation and decoupling water electrolysis continuous hydrogen production system of the present invention; Figure 2 It is a schematic structural diagram of the separation and decoupling water electrolysis reaction module of the present invention; Figure 3 It is a three-dimensional structural schematic diagram of the Johnson mesh ring sleeve of the present invention; Figure 4 The Ni 0.9 Co 0.1 Galvanostatic charging curves of (OH)2 anode in 5M KOH aqueous electrolyte; Figure 5 The present invention adopts Ni 0.9 Co 0.1 Cyclic voltammogram in 5M KOH aqueous solution when (OH)2 is used as redox mediator.

[0022] The following are the descriptions of the reference numerals: 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. Reduction medium inlet; 110. Oxidation medium outlet; 111. Cathode wire protection sleeve; 112. Decoupling cyclone; 112a. Columnar cyclone chamber; 112b. Centrifugal separation chamber; 112c. Spiral guide vane; 112d. Inner sleeve ; 113. Crude hydrogen outlet; 114. Top cover; 115. Air pressure balance valve; 116. Cathode electrode interface; 117. Anode electrode interface; 118. Fixed connection frame; 119. Anode wire protection cover; 2. Hydrogen purification and collection module; 201. Condenser; 202. Deoxidizer; 203. Dryer; 3. Redox medium recycling 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

[0023] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0024] 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 circulation regeneration module 3 and a separation and decoupling control module 4. When the above system is operating normally, the separation and decoupling water electrolysis reaction module 1 generates crude hydrogen and an oxidized redox medium, the oxidized medium enters the redox medium circulation regeneration module 3 to be heated to release oxygen and returns to the separation and decoupling water electrolysis reaction module 1 after reduction and regeneration, the crude hydrogen is purified and collected by the hydrogen purification and collection module 2, and the entire system dynamically controls the operating parameters through the separation and decoupling control module 4 to achieve current voltage-oxygen concentration-temperature joint control.

[0025] 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 lower part of the insulating shell 101. The chamber above the partition plate 103 is a decoupling electrolysis chamber 105, and the lower part is an electrolyte replenishing chamber 102. A plurality of fluid distributors 104 are provided on the partition plate 103; 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, 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 wire outside 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, and a gas pressure balance valve 115 is also provided on the top cover 114. A plurality of fixed connecting frames 118 are arranged along the circumferential direction above the Johnson mesh ring sleeve 106, and the annular inert anode electrode 108 is connected to the fixed connecting frame 118. The bottom of the Johnson mesh ring sleeve 106 is connected to the partition plate 103. A decoupling cyclone 112 is arranged above the Johnson mesh ring sleeve 106, and the upper part of the decoupling cyclone 112 is connected to a crude hydrogen outlet 113, and the lower part is connected to an oxidized medium outlet 110. The lower part of the decoupling electrolysis chamber 105 is connected to a reduced medium inlet 109, and the electrolyte replenishing chamber 102 is connected to an electrolyte inlet 102a. The 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. When the device is in operation, the electrolyte is replenished through a replenishment signal, and the redox medium particles are fluidized through the fluid distributor 104 on the bottom partition plate 103 to 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, so as to replenish the electrolyte for the decoupling electrolysis chamber 105 .

[0026] 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. In order 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 arranged between the electrodes, and the Johnson mesh ring sleeve 106 is fixedly arranged 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.

[0027] The cathode electrode 107 is arranged inside the Johnson mesh ring sleeve 106. In this embodiment, the cathode electrode 107 is a stainless steel mesh electrode plated with a nickel-platinum coating, and the surface is coated with a hydrogen evolution reaction (HER) catalyst to minimize the reaction barrier of the hydrogen evolution reaction (HER). The annular inert anode electrode 108 is a glassy carbon electrode connected to the positive electrode of the power supply, and the surface is not covered with a catalyst. The connection between the anode electrode 108 and the cathode electrode 107 is respectively provided with a wire protection tube connected to the top electrode interface. During the electrolysis process, hydrogen is generated by an electrochemical reaction at the cathode electrode 107, and the redox medium 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 decomposition, so that the time of generating oxygen and hydrogen is separated, and the simultaneous generation of gas mixing is avoided. At the same time, the design of the fluidized redox medium optimizes the oxygen storage capacity and improves the overall stability and efficiency of the reaction system.

[0028] 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 sequentially purifying, refining and collecting hydrogen; The redox medium recycling module 3 includes a pyrolysis pool 303 connected to the oxidized medium outlet 110 and used to generate oxygen. The pyrolysis pool 303 is connected to the cooling pool 301 through a circulation pump 302. The cooling pool 301 is connected to the reduced medium inlet 109. An axial stirrer, a constant temperature heater, and a thermometer are provided in the pyrolysis pool 303. The temperature in the pyrolysis pool 303 is maintained at T1 by a constant temperature heater, 93°C≤T1≤97°C, and the fluctuation peak value is ≤3°C.

[0029] Furthermore, a spiral heat exchange tube is provided inside the cooling pool 301 in the redox medium recycling module 3, and the medium temperature is lowered to a temperature at which the self-discharge reaction is completely stopped, that is, below 50° C., by external cooling water.

[0030] 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.

[0031] As a preferred embodiment, the decoupling cyclone 112 includes an integrally formed columnar vortex chamber 112a and a centrifugal separation chamber 112b, wherein the columnar vortex chamber 112a is arranged above the centrifugal separation chamber 112b; an inner sleeve 112d is provided in the columnar vortex chamber 112a, a plurality of spiral guide vanes 112c are arranged between the columnar vortex chamber 112a and the inner sleeve 112d, and the inner sleeve 112d is connected to a crude hydrogen outlet 113; the centrifugal separation chamber 112b is connected to an 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 gas phase hydrogen, liquid phase electrolyte, and solid phase 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 arranged with a number of spiral guide vanes 112c, which are used to create 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.

[0032] 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, 0.5mm≤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 have a redox reaction potential in the electrolyte of the anode cell that is lower than the oxygen evolution reaction potential, and can store oxygen free radicals. The redox medium is prepared by coating high-purity ultrafine nickel powder on a conductive substrate using an electrodeposition method.

[0033] In the embodiment of the present invention, 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 evenly dispersed in the electrolyte of the anode cell, and the redox reaction is carried out 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 .

[0034]

[0035] The medium is evenly dispersed in the alkaline electrolyte, acting as an electron-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 hydroxide ions produced are transferred to the redox medium through the electrolyte, and then the medium undergoes a forward oxidation reaction (Rxn.1 forward) and absorbs the hydroxide ions produced by the HER. The hydroxide ions are transferred to the medium through the electrolyte and then absorbed by Ni 0.9 Co 0.1 (OH)2 is absorbed by oxidation reaction and converted into Ni 0.9 Co 0.1 OOH:

[0036]

[0037] 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 In 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 embodiment) follows the self-discharge acceleration of the Arrhenius equation (Eq. 1): 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.

[0038] 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 electrolyte, and the medium is evenly dispersed in the anode cell. When the current is connected, an oxidation reaction occurs on the surface of the medium, but no oxygen is produced. At this time, the electrolysis process occurring in the separation and decoupling water electrolysis reaction module 1 is mainly used to produce a single hydrogen. The generated hydrogen is collected by a gas collection device externally connected to the crude hydrogen outlet 113.

[0039] 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 enough 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, and 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 thermostatic heater in the pyrolysis cell is kept in working state to ensure the constant pyrolysis temperature. The generated oxygen is collected by a gas collection device external to the pyrolysis cell.

[0040] The specific experimental cases are as follows: The separation decoupled water electrolysis continuous hydrogen production system provided by the present invention is applied to the decoupled water electrolysis experiment, and the present invention is further illustrated by experimental cases. 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.

[0041] 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 figure overlays the steady-state current-potential diagrams 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 .

[0042] 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 (about 50% under the working condition shown in the figure), its anode potential changes from 1.4 V to RHE Rapidly increases to 1.5 V RHE. Near this point, the charging potential platform gradually moves toward the OER platform, and the oxygen storage anode begins to evolve into an overcharged anode. In the present invention, this situation must be avoided. In order to ensure that the HER in the electrolytic cell stops before the medium is overcharged, the following measures must be taken: setting a potential limit for the charging anode, a charge limit, a voltage limit (between the anode and the cathode), or achieving effective control by monitoring the dissolved oxygen concentration.

[0043] From the experimental results, it can be seen that hydrogen is generated by electrochemical reaction, so its generation rate is directly controlled by the applied current density; while oxygen is generated in a spontaneous chemical reaction under heating conditions, and its production rate cannot be directly controlled by current density. However, by adjusting the temperature, the regeneration rate of the anode can be controlled, thereby inhibiting the initial oxygen generation that occurs at near ambient temperature and accelerating the second step of oxygen generation at high temperature (95°C). Therefore, temperature is a key control parameter in this decoupled water electrolysis system, which can slow down or accelerate the generation of oxygen in the electrolytic cell and the pyrolysis cell, respectively, similar to the temperature swing 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 stage. However, through external monitoring, this process can be effectively controlled to slow down the rate of oxygen generation.

[0044] The present invention also provides a method for using a separation and decoupling water electrolysis continuous hydrogen production system, using the above separation and decoupling water electrolysis continuous hydrogen production system, comprising the following steps: (1) Decoupling the decoupling electrolysis chamber 105 to produce crude hydrogen and oxidize the reduced medium at the same time, and the decoupling cyclone 112 separates the crude hydrogen from the oxidized medium; (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; (3) Purifying, refining and collecting the crude hydrogen using the condenser 201, the deoxidizer 202 and the dryer 203; (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.

[0045] Furthermore, the operating parameters dynamically regulated 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 an 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. 2 The safety threshold when oxygen exceeds the limit is ≤50 mA / cm 2 ; The current and voltage control unit 401 uses a three-electrode potential control system, a reference electrode is added inside the anode electrode 108, and the polarization potential between the anode and the reference electrode is monitored in real time by a constant potential instrument; 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.

[0046] Further, potential and voltage regulation: the polarization potential of the anode is monitored in real time according to the potentiometer, so that the polarization potential always meets the oxidation threshold setting. The upper limit of the oxidation threshold needs to be at least 0.2V lower than the starting potential of the oxygen evolution reaction of the redox medium (calibrated by the linear sweep voltammetry pre-test system) to inhibit the oxygen evolution side reaction; the lower limit setting needs to be 0.2V higher than the complete oxidation potential of the redox medium (calibrated by the linear sweep voltammetry pre-test system) to ensure that the reaction proceeds fully.

[0047] 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.

[0048] Pyrolysis cell temperature control: The pyrolysis cell temperature is stabilized at 95±2°C by a constant temperature heater (resistance heating device). The temperature sensor feeds back data to the controller in real time. If the temperature exceeds the threshold, the heating power is cut off and a shutdown signal is sent to the electrolytic cell.

[0049] Linkage control of medium circulation rate: The flow sensor monitors the circulation flow rate of the redox medium and controls the charge amount of the redox medium. When the system is operating normally, the circulation flow rate is controlled to be constant at 30L / min; when the hydrogen production rate of the electrolytic cell drops to 80% of the limit value, the circulation flow rate is reduced to 10L / min, and the replenishment pump is automatically triggered to inject the backup medium. The limit value is calibrated by the pre-test system; the oxygen concentration monitoring unit 402 at the crude hydrogen outlet 113 monitors the oxygen concentration to prevent the redox medium from overcharging. If the monitored oxygen concentration value exceeds 0.02%, the circulation flow rate is increased to 30L / min; if the oxygen concentration exceeds the limit (>0.1%), the system immediately cuts off the circulation pump 302.

[0050] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A separation and decoupling water electrolysis continuous hydrogen production system, characterized in that: Includes the following modules: A separation and decoupling water electrolysis reaction module comprises an insulating shell, wherein a partition plate is provided near the lower part 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 a plurality of fluid distributors are provided on the partition plate; a Johnson mesh ring sleeve is provided in the decoupling electrolysis chamber, wherein a 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, wherein 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; and the lower part of the decoupling electrolysis chamber is connected to a reduced medium inlet; A hydrogen purification and collection module, including a condenser, a deoxidizer and a dryer connected to the crude hydrogen port and sequentially purifying, refining and collecting hydrogen; The redox medium circulation 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 through a circulation pump, the cooling pool is connected to the reduced medium inlet, and the temperature in the pyrolysis pool is maintained at T 1， 93℃≤T1≤97℃, fluctuation peak-to-peak value ≤3℃.

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

4. According to claim 1, a separation and decoupling water electrolysis continuous hydrogen production system is characterized in that: A plurality of fixed connection frames are arranged on the top of 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; 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.

5. According to claim 1, a separation and decoupling water electrolysis continuous hydrogen production system is characterized in that: The redox medium is bimetallic layered double hydroxide particles; The bimetallic layered double hydroxide particles are Ni x Co 1-x (OH)2 particles, where 0<x<1, particle size D1, 0.5mm≤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 .

6. A separation and decoupling water electrolysis continuous hydrogen production system according to claim 5, characterized in that: The potential of the redox reaction of the bimetallic layered double hydroxide particles in the electrolyte of the anode cell is lower than the oxygen evolution reaction potential, and the bimetallic layered double hydroxide particles can store oxygen free radicals.

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

8. 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) Purifying, refining and collecting the crude hydrogen using a condenser, a deoxidizer and a dryer; (4) Using the separation and decoupling control module to dynamically control the operating parameters, the current, voltage, oxygen concentration and temperature joint control of the separation and decoupling water electrolysis continuous hydrogen production system is achieved.

9. The method for using the separation and decoupling water electrolysis continuous hydrogen production system according to claim 8, characterized in that: The operating parameters dynamically regulated 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 .

10. The method for using the separation and decoupling water electrolysis continuous hydrogen production system according to claim 9, characterized in that: The current and voltage control unit uses a three-electrode potential control system, a reference electrode is added inside the anode electrode, and the polarization potential between the anode and the reference electrode is monitored in real time by a constant potential instrument; the polarization potential always meets the selective oxidation threshold setting, 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.

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