Intermittent electrolysis supercritical water hydrogen production and electrochemical measurement system and method

Abstract

The invention discloses an intermittent electrolysis supercritical water hydrogen production and electrochemical measurement system and method. The measurement system comprises a supercritical water electrolyzer, a direct current power supply device, a first supercritical water storage tank and a second supercritical water storage tank, wherein the bottom of the electrolysis supercritical water generator is provided with a heating device, the top of the supercritical water electrolyzer is provided with an outlet, the outlet is divided into two paths, one path is connected with the first supercritical water storage tank, and the other path is connected with the second supercritical water storage tank; the supercritical water electrolyzer is connected with the direct-current power supply device; and the supercritical water electrolyzer adopts a three-electrode system. The measuring system provided by the invention adopts a three-electrode system, and can accurately measure the electrochemical behavior of supercritical water electrolysis. The supercritical water reactor can better adapt to different electrochemical reduction oxidation systems, the cathode is subjected to an electrocatalytic hydrogen evolution reaction, the anode completes an organic matter oxidation reaction, and hydrogen production and organic matter treatment are synchronously achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen production, and in particular relates to an intermittent supercritical water electrolysis hydrogen production and electrochemical measurement system and method. Background Art

[0002] Supercritical water (SCW) refers to water at a temperature and pressure exceeding its critical point (374°C, 22.1MPa). In the supercritical state, water is neither liquid nor gas, but in a special fluid state with unique physical and chemical properties, such as high solubility, low viscosity and high diffusion coefficient. These characteristics have broad application prospects in the fields of energy, chemical industry, environmental protection, etc. Supercritical water has been widely studied and applied in the fields of gasification and oxidation. As an excellent reaction medium, it can promote the harmless treatment of organic solid waste. At the same time, the production of hydrogen by electrocatalytic decomposition of supercritical water breaks through the mild operating conditions of traditional water electrolysis hydrogen production. The excellent solubility and high diffusivity of the supercritical water medium are coupled with the directional driving effect of the external electric field, which can achieve high efficiency of hydrogen production on the basis of low energy consumption.

[0003] As an important means of efficient conversion of organic matter and clean hydrogen production, supercritical water gasification (SCWG) and supercritical water oxidation (SCWO) technologies have shown mature application potential in many fields. However, they still face key challenges in practical applications: First, the existing technologies have significantly low energy conversion efficiency and prominent contradictions with operational economy. The SCWG system needs to maintain a high temperature environment above 800°C, and the energy consumption per kilogram of dry biomass treatment is as high as 10-15MJ, which makes the energy conversion efficiency of the heat integration system less than 40%, which is significantly different from the efficient use of energy. Supercritical water gasification and supercritical water oxidation require a lot of energy to maintain a high temperature and high pressure environment. These energy consumptions include the energy required for heating equipment to reach the reaction temperature, the energy required for compressed gas (such as oxygen) to reach the required pressure, and the energy required during the medium circulation process. High energy consumption not only increases operating costs, but may also lead to higher carbon emissions, especially when energy mainly relies on fossil fuels, which is not conducive to environmental protection. The effect is limited for some difficult-to-decompose organic compounds, and higher temperatures or pressures, or longer reaction times, may be required, which may reduce treatment efficiency and increase energy consumption.

[0004] In addition, in the original technology of electrochemically treating organic substances, a large amount of special solvents are required to dissolve the organic matter. When treating organic substances on a large scale, the extensive use of special solvents often brings a high cost to the system. Moreover, different special solvents need to be used to treat different types of organic substances, and it is often difficult to achieve the best results in actual operation. Summary of the Invention

[0005] To overcome the problems of inefficient, high-cost, and polluting treatment of organic substances in the prior art, the object of the present invention is to provide an intermittent electrolysis supercritical water hydrogen production and electrochemical measurement system and method. This system can utilize electrochemical action to treat various organic substances in a supercritical water medium and produce hydrogen, high-value-added organic substances, etc., and can also measure and collect electrochemical parameters in a supercritical water environment.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] An intermittent electrolysis supercritical water hydrogen production and electrochemical measurement system includes a supercritical water electrolyzer, a DC power supply device, a first supercritical water storage tank, and a second supercritical water storage tank;

[0008] Among them, a heating device is provided at the bottom of the electrolytic supercritical water generator. An outlet is provided at the top of the supercritical water electrolyzer. The outlet is divided into two paths. One path is connected to the first supercritical water storage tank, and the other path is connected to the second supercritical water storage tank. The supercritical water electrolyzer is connected to the DC power supply device. The supercritical water electrolyzer adopts a three-electrode system.

[0009] Furthermore, it also includes: a pure water tank, a booster pump, and a first solenoid valve. The pure water tank is connected to the supercritical water electrolyzer through the booster pump and the first solenoid valve.

[0010] Furthermore, a heating device is provided at the bottom of the supercritical water electrolyzer.

[0011] Furthermore, a temperature monitoring device and a pressure monitoring device are provided inside the supercritical water electrolyzer. An inlet and an outlet are provided on the pure water tank. The inlet of the pure water tank is connected to a raw material inlet pipe.

[0012] Furthermore, the supercritical water electrolyzer includes a housing. A supercritical water inlet is provided at one end of the housing. A reference electrode, a first working electrode, and a second working electrode are provided in the upper part of the housing. A first supercritical water outlet is provided on one side of the top surface of the housing, and a second supercritical water outlet is provided on the other side. The DC power supply device is connected to the reference electrode, the first working electrode, and the second working electrode through wires to form a closed loop.

[0013] Further, it further includes: a second solenoid valve and a third solenoid valve. The second solenoid valve is connected to the second supercritical water outlet, and the third solenoid valve is connected to the first supercritical water outlet.

[0014] An intermittent electrolytic supercritical water hydrogen production method includes the following steps:

[0015] Add the organic matter slurry into the supercritical water electrolyzer (105), heat it to the supercritical state, start the DC power supply device (106), conduct electrolysis, and after the electrolysis is completed, cool the supercritical water to the liquid state at normal pressure to complete hydrogen production; wherein, the organic matter slurry includes organic matter, liquid water, and an electrolyte additive.

[0016] Further, the organic matter is one or more of agricultural and forestry biomass, waste plastics, kitchen waste, municipal sludge, and organic sewage, and the water for electrolytic water hydrogen production is supercritical water.

[0017] Further, the electrolyte additive is NaSO4, NaCl, Na2CO3, NaNO3, Na2HPO4, NaH2PO4, KCl, K2SO4, KNO3, K2HPO4, K3PO4, LiCl, LiNO3, MgCl2, MgSO4, CaCl2, Al2(SO4)3, Sr(NO3)2, Ce(NO3)3, Zr(NO3)4, Co(NO3)2, AgNO3, KOH, NaOH, Ba(OH)2, NH3·H2O, NaHCO3, Na2CO3, H3PO4, H2CO3, HClO, H2SO3, H2CO3, C6H5OH, HCOOH, CH3COOH, H2CO3, H2SiO3, HClO4, HClO3, HClO2, HClO, H2SO4, HI, HBr, HCl, HNO3, CO2, CO, NH3, or H2O2.

[0018] An electrochemical measurement method includes the following steps:

[0019] Add water into the supercritical water electrolyzer, heat it to the supercritical state, connect the supercritical water electrolyzer to an electrochemical workstation, and conduct measurements of various electrochemical characteristics and electrode reaction characteristics.

[0020] Further, the electrochemical and electrode reaction characteristics in a supercritical water environment are measured.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] The intermittent electrolysis of supercritical water for hydrogen production and electrochemical measurement system of the present invention adopts a three-electrode system, which can accurately measure the electrochemical behavior of supercritical water electrolysis. At the same time, the supercritical water reactor can better adapt to different electro-reduction oxidation systems, the cathode undergoes an electrocatalytic hydrogen evolution reaction (HER), the anode completes the oxidation of organic matter, and the hydrogen production and organic matter treatment are realized simultaneously, and the electrocatalytic reaction reduces the oxidation temperature of the organic matter, while the oxidation exotherm maintains the high temperature requirement of supercritical water. By adjusting the voltage, the selectivity of the target product can be improved. The oxidative decomposition of organic matter replaces the electrochemical supercritical water oxidation, inhibits the production of oxygen, reduces the hydrogen-oxygen mixing ratio, improves the purity of the hydrogen product, and facilitates the separation of the product gas, providing an original solution for breaking through the bottleneck of the existing technology. This system can also be used as a conventional dual-electrode arrangement to achieve industrial production.

[0023] Furthermore, by setting up a temperature monitoring device and a pressure monitoring device, the working temperature and working pressure of the supercritical water electrolyzer can be determined by the weight of the organic matter slurry introduced before production. For example, when 50 ml of a slurry is introduced into the reactor and heated to 400 ° C, the pressure is 25 MPa, and when 100 ml of the slurry is introduced and heated to 400 ° C, the pressure is 30 MPa, and the temperature and pressure have a one-to-one correspondence. Therefore, this system can only use the heater to achieve the pressurization process through constant volume heating and accurately control the reaction conditions inside the reactor.

[0024] The intermittent supercritical water electrolysis hydrogen production and electrochemical measurement system in the present invention is a high temperature and high pressure resistant in-situ electrochemical sensing system, which overcomes the difficulty of real-time monitoring and regulation under supercritical water electrolysis conditions. The in-situ dynamic collection of interface potential distribution, local current density and electrochemical impedance spectrum during the electrolysis process is achieved through the supercritical water electrolysis hydrogen production and electrochemical measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural diagram of the intermittent supercritical water electrolysis hydrogen production and electrochemical measurement system of the present invention;

[0026] Figure 2 It is a side view of a supercritical water electrolyzer;

[0027] Figure 3 It is a top view of a supercritical water electrolyzer;

[0028] In the figure, 101 is a pure water tank, 102 is a booster pump, 103 is a first solenoid valve, 104 is a heating device, 105 is a supercritical water electrolyzer, 106 is a DC power supply device, 107 is a second solenoid valve, 108 is a third solenoid valve, 109 is a first supercritical water storage tank, 110 is a second supercritical water storage tank, 111 is a temperature monitoring device, and 112 is a pressure monitoring device; 1051 is a supercritical water inlet, 1052 is a reference electrode, 1053 is a first working electrode, 1054 is a second working electrode, and 1055 is a first supercritical water outlet. Detailed implementation mode

[0029] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0030] In addition, an element in the present invention is referred to as being "fixed to" or "disposed on" another element, and it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0031] In a typical embodiment of the present invention, please refer to Figure 1 , Figure 1 is a schematic structural diagram of a preferred embodiment of the intermittent electrolytic supercritical water hydrogen production and electrochemical measurement system provided by the present invention; an intermittent electrolytic supercritical water hydrogen production and electrochemical measurement system includes a pure water tank 101, a booster pump 102, a first solenoid valve 103, an auxiliary heating device 104 of a supercritical water electrolyzer, a supercritical water electrolyzer 105, a DC power supply device 106, a second solenoid valve 107, a third solenoid valve 108, a first supercritical water storage tank 109, a second supercritical water storage tank 110, a temperature monitoring device 111 and a pressure monitoring device 112.

[0032] Among them, the pure water tank 101 is connected to the supercritical water electrolyzer 105 through the booster pump 102 and the first solenoid valve 103. A heating device 104 is provided at the bottom of the electrolytic supercritical water generator 105. An outlet is provided at the top of the supercritical water electrolyzer 105. The outlet is divided into two paths. One path is connected to the first supercritical water storage tank 109, and the other path is connected to the second supercritical water storage tank 110. The supercritical water electrolyzer 105 is connected to the DC power supply device 106.

[0033] The pure water tank 101 is used to store raw water. The pressure of the raw water is increased by the booster pump 102 and pumped into the supercritical water electrolyzer 105 via the first solenoid valve 103. The heat of the supercritical water electrolyzer 105 is provided by its attached heating device 104. The DC power supply device 106 is electrically connected to the supercritical water electrolyzer 105; the pressure monitoring device 112 is arranged inside the supercritical water electrolyzer 105, and the pressure monitoring device 112 is used to monitor the internal pressure of the supercritical water electrolyzer 105; the temperature monitoring device 111 is arranged inside the supercritical water electrolyzer 105, and the temperature monitoring device 111 is used to monitor the internal temperature of the supercritical water electrolyzer 105.

[0034] It should be noted that in this embodiment, the pure water tank 101 is provided with an inlet and an outlet. The inlet of the pure water tank 101 is connected to the raw water inlet pipe, and the outlet of the pure water tank 101 is connected to the inlet end of the booster pump 102.

[0035] The supercritical water electrolyzer 105 is provided with an inlet and two outlets. The inlet of the supercritical water electrolyzer 105 is connected to the first solenoid valve 103. One outlet of the supercritical water electrolyzer 105 is connected to the first supercritical water storage tank 109, and the other outlet of the supercritical water electrolyzer 105 is connected to the second supercritical water storage tank 110.

[0036] The DC power supply device 106 is used to provide electrical energy. Electric current is passed into the supercritical water electrolyzer 105 through a wire and electrodes are arranged therein to achieve the electrolysis reaction of water.

[0037] The first supercritical water storage tank 109 and the second supercritical water storage tank 110 are used to store the electrolysis products released from the outlets of the electrolytic supercritical water reactor 105.

[0038] See Figure 2 And Figure 3 As shown in, the supercritical water electrolyzer 105 is a reaction kettle, including a shell, a supercritical water inlet 1051, a reference electrode 1052, a first working electrode 1053, a second working electrode 1054, a first supercritical water outlet 1055 and a second supercritical water outlet 1056; wherein, a supercritical water inlet 1051 is arranged at one end of the shell, a reference electrode 1052, a first working electrode 1053 and a second working electrode 1054 are arranged in the upper part of the shell, a first supercritical water outlet 1055 is arranged on one side of the top surface of the shell, and a second supercritical water outlet 1056 is arranged on the other side. The DC power supply device 106 is connected to the reference electrode 1052, the first working electrode 1053 and the second working electrode 1054 through wires to form a closed loop. The second solenoid valve 107 is connected to the second supercritical water outlet 1055, and the third solenoid valve 108 is connected to the first supercritical water outlet 1055.

[0039] The reference electrode 1052, the first working electrode 1053, and the second working electrode 1054 are made of platinum sheets, platinum wires, and other precious metal alloys. This system can also be used to test the performance and durability of electrodes, so this function can be achieved by replacing electrodes of different types and materials.

[0040] An electrolytic supercritical water hydrogen production method of the present invention includes the following steps:

[0041] 1) Supplementary organic matter slurry is added to the raw material tank 101. The slurry is obtained by mixing an organic matter (such as one or several of agricultural and forestry biomass, waste plastics, kitchen waste, municipal sludge, and organic sewage), an electrolyte additive, etc. with liquid water and then pulping through a pulping machine. Among them, the electrolyte additive is NaSO4, NaCl, Na2CO3, NaNO3, Na2HPO4, NaH2PO4, KCl, K2SO4, KNO3, K2HPO4, K3PO4, LiCl, LiNO3, MgCl2, MgSO4, CaCl2, Al2(SO4)3, Sr(NO3)2, Ce(NO3)3, Zr(NO3)4, Co(NO3)2, AgNO3, KOH, NaOH, Ba(OH)2, NH3·H2O, NaHCO3, Na2CO3, H3PO4, H2CO3, HClO, H2SO3, H2CO3, C6H5OH, HCOOH, CH3COOH, H2CO3, H2SiO3, HClO4, HClO3, HClO2, HClO, H2SO4, HI, HBr, HCl, HNO3, CO2, CO, NH3, or H2O2.

[0042] The mass ratio of the organic matter, liquid water, and electrolyte additive is determined by the on-site working conditions, generally meeting the requirements of qualified conductivity and ensuring that the organic matter and electrolyte no longer precipitate.

[0043] 2) After calculating the thermodynamic properties of the slurry by analyzing the slurry composition, a quantitative slurry is pumped into the supercritical water electrolyzer through the first solenoid valve 103.

[0044] 3) The quantitative slurry is heated to the supercritical state, and the state of the slurry is determined by the temperature sensor and pressure sensor arranged in the electrolyzer.

[0045] 4) Start the DC power supply device 106 for electrolysis.

[0046] 5) After electrolysis is completed, cool the supercritical water to liquid normal pressure. Open the second solenoid valve 107 and the third solenoid valve 108 to separate the products into the supercritical water storage tank.

[0047] An electrochemical measurement method for an electrochemical measurement device to carry out electrochemical measurement in a supercritical water environment includes the following steps:

[0048] 1) Supplementary organic matter slurry is added to the raw material tank 101. The slurry is obtained by pulping after mixing organic matter (such as one or more of agricultural and forestry biomass, waste plastics, food waste, municipal sludge, and organic sewage), electrolyte additives (NaSO4, NaCl, Na2CO3, NaNO3, Na2HPO4, NaH2PO4, KCl, K2SO4, KNO3, K2HPO4, K3PO4, LiCl, LiNO3, MgCl2, MgSO4, CaCl2, Al2(SO4)3, Sr(NO3)2, Ce(NO3)3, Zr(NO3)4, Co(NO3)2, AgNO3, KOH, NaOH, Ba(OH)2, NH3·H2O, NaHCO3, Na2CO3, H3PO4, H2CO3, HClO, H2SO3, H2CO3, C6H5OH, HCOOH, CH3COOH, H2CO3, H2SiO3, HClO4, HClO3, HClO2, HClO, H2SO4, HI, HBr, HCl, HNO3, CO2, CO, NH3 or H2O2), etc. with liquid water through a pulping machine. Among them, the mass ratio of the organic matter, liquid water, and electrolyte additive is determined by the on-site working conditions, generally meeting the requirements of qualified conductivity and ensuring that the organic matter and electrolyte no longer precipitate.

[0049] 2) After calculating the thermodynamic properties of the slurry by analyzing the slurry composition, a quantitative slurry is pumped into the supercritical water electrolyzer through the first solenoid valve 103.

[0050] 3) Heat the quantitative slurry to the supercritical state, and the state of the slurry is determined by the temperature sensor and pressure sensor arranged in the electrolyzer.

[0051] 4) Connect an electrochemical workstation as a DC power supply device, and various electrochemical properties and electrode reaction characteristics can be measured by electrochemical analysis means. In the present invention, in-situ dynamic acquisition of common electrochemical parameters such as the interfacial potential distribution, local current density, and electrochemical impedance spectrum during the electrolysis process is realized through the electrolysis of supercritical water to produce hydrogen and the electrochemical measurement system.

[0052] The electrochemical reaction has higher efficiency and selectivity than the thermal chemical reaction. Therefore, in the present invention, by the combined action of the electrochemical effect and the properties of supercritical water itself, the heat required for the conversion of organic matter can be effectively reduced, and the overall operating temperature of the system can be lowered. At the same time, a large amount of heat released by the decomposition of organic matter can achieve self-heating, effectively reducing the total energy consumption of the system.

[0053] To avoid the disadvantages of the large amount of proprietary solvents required for the decomposition of organic substances by the original electrochemical reaction, this system can utilize the physical properties of supercritical water itself to achieve efficient dissolution of organic substances. Moreover, the dissolution properties of supercritical water are significantly correlated with its temperature and pressure. Therefore, by adjusting external parameters such as temperature and pressure, a large change in the dissolution properties of supercritical water can be achieved to meet the dissolution of different organic substances.

[0054] Aiming at the disadvantages of low product selectivity and harsh operating conditions in supercritical water gasification and oxidation technologies, in this invention, external parameters such as temperature and pressure are used to adjust the properties of supercritical water. Thus, the intermolecular forces of organic substances are destroyed by the physical properties of supercritical water itself, prompting them to be quickly dissolved into small-molecule organic substances (such as CH3COOH, C6H 12 O6). An electrocatalytic reaction is introduced into the dissolution system. The anode decomposes organic substances through an oxidation reaction, and the cathode efficiently produces hydrogen through a reduction reaction, ultimately achieving an organic matter conversion rate as high as 95%.

[0055] Aiming at the problem that in supercritical water gasification and oxidation technologies, product decomposition is achieved through a thermal catalytic principle and different products are difficult to separate when mixed in supercritical water, in this invention, through electrode reactions, different products can be spatially separated during the reaction, further reducing the difficulty of subsequent product separation and extraction.

[0056] Aiming at the problems of high energy consumption and low conversion rate in supercritical water gasification and oxidation technologies, in this invention, the decomposition of products by electrochemical action can achieve more efficient conversion and heat release of organic substances, and can better reduce energy consumption compared with existing oxidation and gasification technologies.

[0057] The above is only an illustration of the best embodiment of the present invention, but it should not be construed as a limitation of the claims. The present invention is not limited to the above embodiments, and its specific structure allows for changes. Any changes made within the protection scope of the independent claims of the present invention are within the protection scope of the present invention.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

Claims

1. An intermittent electrolysis supercritical water hydrogen production and electrochemical measurement system, characterized in that, It includes a supercritical water electrolyzer (105), a DC power supply device (106), a first supercritical water storage tank (109), and a second supercritical water storage tank (110); Among them, a heating device (104) is provided at the bottom of the electrolytic supercritical water generator (105). An outlet is provided at the top of the supercritical water electrolyzer (105). The outlet is divided into two paths. One path is connected to the first supercritical water storage tank (109), and the other path is connected to the second supercritical water storage tank (110). The supercritical water electrolyzer (105) is connected to the DC power supply device (106). The supercritical water electrolyzer (105) adopts a three - electrode system.

2. The intermittent electrolytic supercritical water hydrogen production and electrochemical measurement system according to claim 1, wherein It also includes: A pure water tank (101), a booster pump (102), and a first solenoid valve (103). The pure water tank (101) is connected to the supercritical water electrolyzer (105) via the booster pump (102) and the first solenoid valve (103).

3. The batch electrolysis supercritical water hydrogen production and electrochemical measurement system according to claim 1, characterized in that, A heating device (104) is provided at the bottom of the supercritical water electrolyzer (105).

4. The batch electrolytic supercritical water hydrogen production and electrochemical measurement system according to claim 1, characterized in that, A temperature monitoring device (111) and a pressure monitoring device (112) are provided inside the supercritical water electrolyzer (105). The pure water tank (101) is provided with an inlet and an outlet. The inlet of the pure water tank (101) is connected to a raw material inlet pipe.

5. The intermittent electrolytic supercritical water hydrogen production and electrochemical measurement system according to claim 1, wherein The supercritical water electrolyzer (105) includes a housing. A supercritical water inlet (1051) is provided at one end of the housing. A reference electrode (1052), a first working electrode (1053), and a second working electrode (1054) are provided in the upper part of the housing. A first supercritical water outlet (1055) is provided on one side of the top surface of the housing, and a second supercritical water outlet (1056) is provided on the other side. The DC power supply device (106) is connected to the reference electrode (1052), the first working electrode (1053), and the second working electrode (1054) through wires to form a closed loop.

6. The intermittent electrolytic supercritical water hydrogen production and electrochemical measurement system according to claim 5, characterized in that, It also includes: A second solenoid valve (107) and a third solenoid valve (108). The second solenoid valve (107) is connected to the second supercritical water outlet (1055), and the third solenoid valve (108) is connected to the first supercritical water outlet (1055).

7. An intermittent electrolytic supercritical water hydrogen production method based on the system described in claim 1, characterized in that, It includes the following steps: Adding an organic matter slurry into the supercritical water electrolyzer (105), heating it to the supercritical state, starting the DC power supply device (106) for electrolysis. After electrolysis is completed, cooling the supercritical water to the liquid state at normal pressure to complete hydrogen production. Among them, the organic matter slurry includes organic matter, liquid water, and an electrolyte additive.

8. The intermittent electrolytic supercritical water hydrogen production method according to claim 7, characterized in that, The organic matter is one or more of agricultural and forestry biomass, waste plastics, kitchen waste, municipal sludge, and organic sewage. The water for electrolytic hydrogen production is supercritical water.

9. The intermittent electrolytic supercritical water hydrogen production method according to claim 7, characterized in that, The electrolyte additives are NaSO4, NaCl, Na2CO3, NaNO3, Na2HPO4, NaH2PO4, KCl, K2SO4, KNO3, K2HPO4, K3PO4, LiCl, LiNO3, MgCl2, MgSO4, CaCl2, Al2(SO4)3, Sr(NO3)2, Ce(NO3)3, Zr(NO3)4, Co(NO3)2, AgNO3, KOH, NaOH, Ba(OH)2, NH3·H2O, NaHCO3, Na2CO3, H3PO4, H2CO3, HClO, H2SO3, H2CO3, C6H5OH, HCOOH, CH3COOH, H2CO3, H2SiO3, HClO4, HClO3, HClO2, HClO, H2SO4, HI, HBr, HCl, HNO3, CO2, CO, NH3 or H2O2; The mass ratio of the organic matter, liquid water and the electrolyte additive is determined by the on-site working conditions, generally meeting the requirements that the conductivity is qualified and the organic matter and the electrolyte no longer precipitate.

10. An electrochemical measurement method based on the system according to any one of claims 1-9, characterized in that, It includes the following steps: Add water into the supercritical water electrolyzer (105), heat it to the supercritical state, connect the supercritical water electrolyzer (105) to an electrochemical workstation, and measure various electrochemical characteristics and electrode reaction characteristics.

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