Electro-catalytic hydrogen production and energy storage combined cycle system and performance recovery method

Abstract

The invention discloses an electro-catalysis hydrogen production and energy storage combined cycle system and a performance recovery method, the electro-catalysis hydrogen production and energy storage combined cycle system comprises a flow battery, a hydrogen production generator and a sulfenyl reaction system, the hydrogen production generator is connected with a second storage tank of the flow battery for storing a negative electrode electrolyte; the negative electrode electrolyte is regenerated in the hydrogen production generator and generates hydrogen in the hydrogen production generator; the sulfenyl reaction system is used for reducing active substances in the positive electrode electrolyte in the first storage tank and supplementing hydrogen ions into the positive electrode electrolyte, the sulfenyl reaction system comprises a hydrothermal reactor and an oxidation battery, and the positive electrode electrolyte in the first storage tank can be conveyed into the hydrothermal reactor and reacts with a sulfenyl compound; a solution in the hydrothermal reactor can be conveyed into the positive electrode side of the oxidation battery, and a solution in the third chamber can flow back into the first storage tank; and the remaining positive electrolyte in the first storage tank can be conveyed to the negative electrode side of the oxidation battery. According to the invention, the auxiliary energy consumption can be reduced, the electricity storage capacity can be improved, and continuous and controllable electro-catalytic hydrogen production can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production, and specifically relates to an electrocatalytic hydrogen production and energy storage combined cycle system and a performance recovery method. Background Art

[0002] In the process of hydrogen production from renewable energy, it is difficult to ensure stable electricity consumption and local area network stability for green hydrogen synthesis loads due to the volatility and intermittency of renewable energy generation. When renewable energy generation is high, electricity may be abandoned, and when renewable energy generation is short of electricity, it needs to be connected to the public grid, resulting in a reduction in the proportion of green electricity for hydrogen production.

[0003] In order to adapt to the technical difficulties of renewable energy power generation and hydrogen production, related technologies usually use renewable energy power generation, a high proportion of energy storage, and an external public grid connection to achieve stable hydrogen production, resulting in high overall system costs, high green hydrogen costs, and a low proportion of green electricity. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of the present invention proposes a low auxiliary energy consumption, high power storage capacity and continuously controllable electrocatalytic hydrogen production and energy storage combined cycle system.

[0006] The embodiment of the present invention also provides a performance recovery method.

[0007] The electrocatalytic hydrogen production and energy storage combined cycle system of the embodiment of the present invention comprises:

[0008] A liquid flow battery, the liquid flow battery comprising a battery stack, a first storage tank storing a positive electrode electrolyte, and a second storage tank storing a negative electrode electrolyte, wherein the inner cavity of the battery stack comprises a first positive electrode, a first negative electrode, and a first ion exchange membrane, wherein the first ion exchange membrane divides the inner cavity of the battery stack into a first chamber for arranging the first positive electrode and a second chamber for arranging the first negative electrode; the first storage tank is connected to the first chamber and forms a circulation loop so that the positive electrode electrolyte circulates in the first storage tank and the first chamber; the second storage tank is connected to the second chamber and forms a circulation loop so that the negative electrode electrolyte circulates in the second storage tank and the second chamber;

[0009] A hydrogen generator, wherein the hydrogen generator has a hydrogen production catalytic layer, the hydrogen generator is connected to the second storage tank to form a circulation loop, the negative electrode electrolyte is regenerated in the hydrogen generator and hydrogen is produced in the hydrogen generator;

[0010] A sulfur-based reaction system, the sulfur-based reaction system is used to reduce the active material in the positive electrode electrolyte in the first storage tank and supplement hydrogen ions to the positive electrode electrolyte, the sulfur-based reaction system includes a hydrothermal reactor and an oxidation cell, the inner cavity of the hydrothermal reactor is provided with a hydrothermal reaction catalyst layer, the inner cavity of the hydrothermal reactor is connected with the first storage tank, the positive electrode electrolyte in the first storage tank can be transported into the hydrothermal reactor and react with the sulfur-based compound; the inner cavity of the oxidation cell is provided with a second positive electrode, a second negative electrode, a reduction catalyst layer and a second ion exchange membrane, the second ion exchange membrane separates the inner cavity of the oxidation cell into a third chamber for arranging the second positive electrode and the reduction catalyst layer and a fourth chamber for arranging the second negative electrode, the third chamber is connected with the inner cavity of the hydrothermal reactor and the first storage tank so that the solution of the hydrothermal reactor can be transported into the third chamber, and the solution in the third chamber can flow back to the first storage tank; the fourth chamber is connected with the first storage tank and forms a circulation loop so that the positive electrode electrolyte in the first storage tank circulates in the first storage tank and the fourth chamber.

[0011] The electrocatalytic hydrogen production and energy storage combined cycle system of the embodiment of the present invention produces hydrogen by discharging the negative electrode electrolyte, and utilizes a sulfur-based reaction system to achieve performance recovery of the liquid flow battery, thereby improving the system efficiency of the liquid flow battery and achieving low auxiliary energy consumption, high storage capacity, and continuous, controllable and efficient hydrogen production.

[0012] In some embodiments, the sulfur-based reaction system further includes a third storage tank, which is provided on a pipeline for allowing the electrolyte in the third chamber of the oxidation cell to flow to the first storage tank, and on a pipeline for allowing the electrolyte in the fourth chamber of the oxidation cell to flow to the first storage tank, so as to store the electrolyte flowing to the first storage tank.

[0013] In some embodiments, in an initial state, the positive electrolyte and the negative electrolyte in the liquid flow battery are the same, and the supporting electrolytes of the positive electrolyte and the negative electrolyte in the liquid flow battery are acidic media and include at least methanesulfonic acid;

[0014] And / or, the first positive electrode is a TiC / TiO 2 Coated carbon-based electrode, or carbon-based electrode with boron-doped titanium dioxide coating;

[0015] And / or, the battery stack comprises a plurality of battery cells, a positive current collector plate and a negative current collector plate, each of the battery cells comprises the first positive electrode, the first negative electrode and the first ion exchange membrane, and the positive current collector plate and the negative current collector plate connect the plurality of battery cells in series to form the battery stack;

[0016] And / or, it also includes a first heat exchanger, which is arranged on a pipeline for allowing the positive electrode electrolyte to flow from the first storage tank to the first chamber and on a pipeline for allowing the negative electrode electrolyte to flow from the second storage tank to the second chamber.

[0017] In some embodiments, the hydrogen production catalytic layer includes a first substrate layer and first catalytic particles, wherein the first substrate layer is carbon felt, graphite felt, titanium mesh, SiO 2 Any one of the particle fixed beds, wherein the first catalytic particles are MoS 2 Or Mo 2 C particles.

[0018] In some embodiments, the hydrogen generator further comprises a first circulation pump, a first heater, a first agitator and a first feed inlet;

[0019] And / or, the hydrogen production generator is connected to a first pressure gauge and a first compressor.

[0020] In some embodiments, the hydrothermal reaction catalytic layer and the reduction catalytic layer are both carbon-based catalysts, metal catalysts or metal oxide catalysts;

[0021] And / or, the hydrothermal reactor has a second feed port, and the second feed port is used to transport the sulfur-based compound to the inner cavity of the hydrothermal reactor so that the sulfur-based compound undergoes an oxidation reaction in the hydrothermal reactor;

[0022] And / or, further comprising a second pressure gauge, the second pressure gauge being connected to the hydrothermal reactor and used to detect the gas pressure in the hydrothermal reactor, the inner cavity of the hydrothermal reactor also comprising a second circulation pump, a second heat exchanger and a second agitator;

[0023] And / or, it also includes a filter, which is arranged on the pipeline used to allow the solution to flow from the hydrothermal reactor to the third chamber.

[0024] In some embodiments, an oxidation battery purification system is also included, which includes a fourth tank for storing a cleaning agent and a fifth tank for storing a processing solvent. The fourth tank and the fifth tank are both connected to the third chamber and the fourth chamber of the oxidation battery. The positive and negative poles of the power supply for supplying power to the oxidation battery are reversed, and the cleaning agent flowing from the fourth tank into the third chamber reacts in the third chamber and then flows into the fifth tank, and the cleaning agent flowing from the fourth tank into the fourth chamber reacts in the fourth chamber and then flows into the fifth tank, so as to purify the oxidation battery.

[0025] In some embodiments, the processing solvent is an alkaline solution, the cleaning agent is a supporting electrolyte in the electrolyte of the flow battery, and an alkali solution pump is provided on the fifth storage tank. The alkali solution pump is used to drive the alkali solution in the fifth storage tank to self-circulate and spray in the fifth storage tank.

[0026] In some embodiments, a balancing system is also included, which includes a first pipeline, a second pipeline and a balancing pump, the first pipeline and the second pipeline are both connected between the first storage tank and the second storage tank, and the balancing pump is used to drive the electrolyte in the first storage tank to flow from the first pipeline to the second storage tank, and to make the electrolyte in the second storage tank flow from the second pipeline to the first storage tank.

[0027] The performance recovery method of the electrocatalytic hydrogen production and energy storage combined cycle system disclosed in the present invention based on any one of the above embodiments comprises:

[0028] S101, transporting part of the cathode electrolyte in the first storage tank into the hydrothermal reactor, and starting the hydrothermal reactor;

[0029] S102, introducing a sulfur-based compound into the hydrothermal reactor to reduce the active substances in the positive electrode electrolyte in the hydrothermal reactor;

[0030] S103, supplying power to the oxidation battery, delivering the positive electrode electrolyte in the hydrothermal reactor to the positive electrode of the oxidation battery, and delivering part of the positive electrode electrolyte in the first storage tank to the negative electrode of the oxidation battery to reduce the active substance of the positive electrode electrolyte in the oxidation battery;

[0031] S104, transporting the electrolyte after the reaction in the oxidation cell into the first storage tank;

[0032] S105, executing a recharging procedure on the liquid flow battery, and determining whether the performance of the liquid flow battery is restored;

[0033] S106: If not, repeat the above steps.

[0034] In some embodiments, the step S103 of supplying power to the oxidation battery includes: supplying power at 1 mA cm -2 Up to 200mAcm -2 The constant current seal charges the oxidation battery to U 2 , and then maintain a constant voltage U 2 Continue charging until the electrolyte in the hydrothermal reactor and the first storage tank is emptied, wherein U 2 =0.1V to 1V;

[0035] And / or, steps S105 and S106 include: maintaining the battery stack of the flow battery at a constant voltage of 1.2V to 1.4V, and increasing and then decreasing the charging current until the current density is less than or equal to 1 mA cm -2 Up to 10mAcm -2 and does not change, determining whether the total storage capacity of the liquid flow battery reaches the rated value, if so, the performance of the liquid flow battery is restored; if not, repeating steps S101 to S105 until the performance of the liquid flow battery is restored;

[0036] And / or, further comprising a purification process, the purification process comprising: reversing the positive electrode and the negative electrode of the power supply for supplying power to the oxidation battery, delivering a cleaning agent from the fourth storage tank to the positive electrode and the negative electrode of the oxidation battery to dissolve the solid matter deposited in the oxidation battery, and treating the matter discharged from the positive electrode and the negative electrode of the oxidation battery;

[0037] And / or, it also includes a balancing process, which includes: driving the electrolyte in the first storage tank and the second storage tank to circulate multiple times to make the electrolyte in the first storage tank and the second storage tank the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of an electrocatalytic hydrogen production and energy storage combined cycle system according to an embodiment of the present invention.

[0039] Figure 2 is a flow chart of a performance restoration method according to an embodiment of the present invention.

[0040] Reference numerals:

[0041] 1. Liquid flow battery; 11. Battery stack; 12. First storage tank; 13. Second storage tank; 14. First positive electrode; 15. First negative electrode; 16. First ion exchange membrane; 17. First chamber; 18. Second chamber; 19. First heat exchanger;

[0042] 2. Hydrogen generator; 21. First circulation pump; 22. First heater; 23. First stirrer; 24. First pressure gauge; 25. First compressor; 26. First feed inlet; 27. Hydrogen production catalyst layer;

[0043] 3. hydrothermal reactor; 31. hydrothermal reaction catalyst layer; 32. second feed port; 33. second pressure gauge; 34. second circulation pump; 35. second heat exchanger; 36. second agitator; 37. filter;

[0044] 4. oxidation cell; 41. second positive electrode; 42. second negative electrode; 43. second ion exchange membrane; 44. reduction catalyst layer; 45. third chamber; 46. fourth chamber;

[0045] 5. The third storage tank;

[0046] 6. The fourth storage tank;

[0047] 7. The fifth storage tank; 71. Alkali liquid pump;

[0048] 81. First pipeline; 82. Second pipeline; 83. Balancing pump;

[0049] 91. Pump; 92. Valve; 93. First charging power source; 94. Second charging power source; 95. Third charging power source; 96. Energy management and control system. DETAILED DESCRIPTION

[0050] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0051] The electrocatalytic hydrogen production and energy storage combined cycle system of the embodiment of the present invention comprises a liquid flow battery 1, a hydrogen production generator 2 and a sulfur-based reaction system.

[0052] The liquid flow battery 1 includes a battery stack 11, a first storage tank 12 storing a positive electrode electrolyte, and a second storage tank 13 storing a negative electrode electrolyte. The inner cavity of the battery stack 11 is provided with a first positive electrode 14, a first negative electrode 15 and a first ion exchange membrane 16. The first ion exchange membrane 16 divides the inner cavity of the battery stack 11 into a first chamber 17 for arranging the first positive electrode 14 and a second chamber 18 for arranging the first negative electrode 15; the first storage tank 12 is connected to the first chamber 17 and forms a circulation loop so that the positive electrode electrolyte circulates in the first storage tank 12 and the first chamber 17; the second storage tank 13 is connected to the second chamber 18 and forms a circulation loop so that the negative electrode electrolyte circulates in the second storage tank 13 and the second chamber 18.

[0053] The flow battery 1 can be connected to a renewable energy system to be charged by the renewable energy system, such as Figure 1 When the output of the renewable energy system is large, the renewable energy system can supply power to the power loads such as the sulfur-based reaction system. When the output of the renewable energy system is small or the output is predicted to be small in the next period of time, the flow battery 1 can be used to supply power to the power loads.

[0054] The hydrogen generator 2 has a hydrogen production catalytic layer 27. The hydrogen generator 2 is connected to the second storage tank 13 to form a circulation loop. The negative electrode electrolyte is regenerated in the hydrogen generator 2 and hydrogen is produced in the hydrogen generator 2. During the charge / discharge process of the flow battery 1, the negative electrode electrolyte in the second storage tank 13 is pumped into the hydrogen generator 2 for discharge. The electrolyte after the reaction is returned to the second storage tank 13 for the flow battery 1 to continue charging, thereby increasing the storage capacity of the flow battery 1. + Reduced to H 2 , and then supplied to hydrogen users after passing through a compressor. The hydrogen generator 2 is decoupled from the charge and discharge of the flow battery 1, and the hydrogen generator 2 can operate independently. Since the hydrogen production principle is the discharge of the negative electrode electrolyte, the generated hydrogen has no oxygen impurities and does not require purification. According to the needs of hydrogen users, continuous and immediate supply can be achieved.

[0055] During the charging / discharging process of the liquid flow battery 1, the loop system between the hydrogen generator 2 and the second storage tank 13 can be started simultaneously or as needed to realize the dual-loop joint operation of the liquid flow battery 1 charging / discharging and the negative electrode electrolyte hydrogen production. By independently operating hydrogen production, the storage capacity of the liquid flow battery 1 is increased, the flexible decoupling operation of hydrogen production and liquid flow battery 1 charging and discharging is realized, and the power supply stability and hydrogen production response speed of renewable energy hydrogen production are also improved.

[0056] The sulfur-based reaction system is used to reduce the active substances in the positive electrode electrolyte in the first storage tank 12 and replenish hydrogen ions into the positive electrode electrolyte. The sulfur-based reaction system includes a hydrothermal reactor 3 and an oxidation cell 4. The inner cavity of the hydrothermal reactor 3 has a hydrothermal reaction catalytic layer 31. The inner cavity of the hydrothermal reactor 3 is connected to the first storage tank 12. The positive electrode electrolyte in the first storage tank 12 can be transported into the hydrothermal reactor 3 and react with the sulfur-based compound.

[0057] A high proportion (e.g., 4 / 5 volume ratio) of the positive electrode electrolyte in the first storage tank 12 flows into the hydrothermal reactor 3. A certain amount of sulfur-based compounds are injected into the hydrothermal reactor 3, and the sulfur-based compounds include, but are not limited to, hydrogen sulfide, sulfur dioxide, and other sulfur-based compounds. The molar amount of the sulfur-based compound corresponds to the molar amount of the excess x% M in the positive electrode reduced to M0 (for example, if hydrogen sulfide is used as the sulfur-based compound, the molar ratio of hydrogen sulfide to the excess M in the main system is x 1 =1:2). For example, in the hydrothermal reactor 3, hydrogen sulfide reacts as a strong sulfur-based compound under the action of the catalyst layer: H 2 S+2M=S+2M0+2H + , reducing the excess M in the positive electrode of the main system (the reaction process in the sulfur-based hydrothermal reactor 3 and the sulfur-based compound oxidation process in the oxidation battery 4 reduce the main system x% M in total), and replenishing the main system hydrogen ions H + .

[0058] The inner cavity of the oxidation cell 4 is provided with a second positive electrode 41, a second negative electrode 42, a reduction catalyst layer 44 and a second ion exchange membrane 43. The second ion exchange membrane 43 divides the inner cavity of the oxidation cell 4 into a third chamber 45 for arranging the second positive electrode 41 and the reduction catalyst layer 44 and a fourth chamber 46 for arranging the second negative electrode 42. The third chamber 45 is connected to the inner cavity of the hydrothermal reactor 3 and the first storage tank 12 so that the solution of the hydrothermal reactor 3 can be transported into the third chamber 45 and the solution in the third chamber 45 can flow back into the first storage tank 12; the fourth chamber 46 is connected to the first storage tank 12 and forms a circulation loop so that the positive electrode electrolyte in the first storage tank 12 circulates in the first storage tank 12 and the fourth chamber 46.

[0059] After the sulfur-based hydrothermal reaction process in the hydrothermal reactor 3 is completed, the sulfur-based compound oxidation process in the oxidation battery 4 is performed in stages. The oxidation battery 4 is charged, for example, Figure 1 The second charging power source 94 shown in the figure, the oxidation battery 4 performs the sulfur-based compound oxidation process, that is, by charging the remaining sulfur-based compound in the sulfur-based compound oxidation hydrothermal reactor 3, while reducing the excess M in the positive electrode of the main system (the sulfur-based hydrothermal reaction process and the sulfur-based compound oxidation process reduce the main system x% M in total), and replenishing the hydrogen ions H lost by hydrogen evolution in the main system + , sulfur-based compound oxidation cell 4 total reaction: H 2 S+2M=S+2M0+2H + . Wherein S is the positive electrode product of the sulfur-based compound oxidation battery 4, and M0 is the negative electrode product of the sulfur-based compound oxidation battery 4.

[0060] The electrocatalytic hydrogen production and energy storage combined cycle system of the embodiment of the present invention produces hydrogen by discharging the negative electrode electrolyte, and utilizes a sulfur-based reaction system to achieve performance recovery of the liquid flow battery 1 and replenish hydrogen ions, thereby improving the system efficiency of the liquid flow battery 1 and achieving low auxiliary energy consumption, high storage capacity, and continuous, controllable and efficient hydrogen production.

[0061] In some embodiments, the sulfur-based reaction system also includes a third storage tank 5, which is used to allow the electrolyte in the third chamber 45 of the oxidation cell 4 to flow to the pipeline of the first storage tank 12, and is used to allow the electrolyte in the fourth chamber 46 of the oxidation cell 4 to flow to the first storage tank 12. The third storage tank 5 is arranged on the pipeline to flow the electrolyte flowing to the first storage tank 12.

[0062] The electrolyte that flows back to the first storage tank 12 from the fourth chamber 46 of the oxidation battery 4 first flows back to the third storage tank 5 for storage. The third storage tank 5 is provided to cache the positive electrode electrolyte, thereby ensuring that the inlet concentration of the negative electrode reactant of the sulfur-based compound oxidation battery 4 is the highest (from the positive electrode of the main system), significantly reducing the voltage and energy consumption of the sulfur-based compound oxidation battery 4, and improving the overall system efficiency of the liquid flow battery 1.

[0063] The electrolyte that flows back to the first storage tank 12 from the third chamber 45 of the oxidation cell 4 first flows back to the third storage tank 5 for storage. The third storage tank 5 is set to cache the positive electrode electrolyte after the reaction, ensuring that the inlet concentration of the positive electrode reactant of the sulfur-based compound oxidation cell 4 is the highest (the remaining sulfur-based compound from the sulfur-based hydrothermal reactor 3), significantly reducing the voltage and energy consumption of the sulfur-based compound oxidation cell 4, and improving the overall system efficiency of the liquid flow battery 1. The solid sulfur produced by the oxidation of the sulfur-based compound is deposited on the second positive electrode 41 of the oxidation cell 4, and the electrolyte after the reaction flows back to the third storage tank 5. The gas mixture (a small amount of water vapor, hydrogen chloride gas, and incompletely reacted hydrogen sulfide gas) in the gas phase space at the top of the third storage tank 5 can be discharged through the gas phase pipeline.

[0064] In some embodiments, the electrocatalytic hydrogen production and energy storage combined cycle system further includes an oxidation cell 4 purification system, the oxidation cell 4 purification system includes a fourth storage tank 6 for storing a cleaning agent and a fifth storage tank 7 for storing a treatment solvent, the fourth storage tank 6 and the fifth storage tank 7 are both connected to the third chamber 45 and the fourth chamber 46 of the oxidation cell 4, and the positive and negative electrodes of the power supply for supplying power to the oxidation cell 4 are reversed, for example, using Figure 1 The third charging power source 95 shown in the figure has opposite positive and negative poles to the second charging power source 94. The cleaning agent flowing from the fourth tank 6 into the third chamber 45 reacts in the third chamber 45 and then flows into the fifth tank 7. The cleaning agent flowing from the fourth tank 6 into the fourth chamber 46 reacts in the fourth chamber 46 and then flows into the fifth tank 7 to purify the oxidation battery 4.

[0065] Furthermore, the processing solvent is an alkaline solution, the cleaning agent is a supporting electrolyte in the electrolyte of the liquid flow battery 1, and an alkali solution pump 71 is provided on the fifth storage tank 7 to drive the alkali solution in the fifth storage tank 7 to self-circulate and spray in the fifth storage tank 7 to improve the processing effect of the gas or liquid entering the fifth storage tank 7.

[0066] During the sulfur-based compound oxidation operation phase of the oxidation cell 4, trace amounts of sulfur solids are deposited on the second positive electrode 41 of the oxidation cell 4, resulting in electrode passivation. During the purification phase, the oxidation cell 11 is charged, and the positive and negative electrodes of the oxidation cell 11 are reversed in polarity (i.e., the positive and negative electrodes are swapped). The cleaning agent in the fourth storage tank 6 is a supporting electrolyte (such as hydrochloric acid, sulfuric acid, etc.), which flows into the third chamber 45 and the fourth chamber 46 of the oxidation cell 11 respectively, and the sulfur solids on the second positive electrode 41 (actually the negative electrode at this time) are dissolved into polysulfide ions S x - The sulfur compound enters the sulfur-based compound and is discharged to the fifth storage tank 7 for treatment or absorption; the hydrochloric acid decomposes into chlorine gas at the second negative electrode 42 (actually the positive electrode at this time) and enters the sulfur-based compound and is discharged to the fifth storage tank 7 for absorption. The sulfur-based compound oxidation battery 4 is charged with a constant current to a charging voltage U 3 A sharp rise with an inflection point U3B , where U 3B =1.2~1.6V, it means that the trace sulfur solid deposited on the sulfur-based compound oxidation battery 4 has been purified and the passivation problem of the electrode of the sulfur-based compound oxidation battery 4 has been avoided. Since the supporting electrolyte of the flow battery 1 is used as a cleaning agent to avoid the introduction of impurities, the charging is stopped at this time.

[0067] In some embodiments, the electrocatalytic hydrogen production and energy storage combined cycle system also includes a balancing system, which includes a first pipeline 81, a second pipeline 82 and a balancing pump 83. The first pipeline 81 and the second pipeline 82 are both connected between the first storage tank 12 and the second storage tank 13. The balancing pump is used to drive the electrolyte in the first storage tank 12 to flow from the first pipeline 81 to the second storage tank 13, and to make the electrolyte in the second storage tank 13 flow from the second pipeline 82 to the first storage tank 12.

[0068] During the operation of the liquid flow battery 1, part of the ions and water molecules migrate from the negative electrode to the positive electrode through the first ion exchange membrane 16, resulting in an imbalance in the liquid levels of the second storage tank 13 and the first storage tank 12, which in turn leads to a loss of charge and discharge capacity of the liquid flow battery 1. After the sulfur-based hydrothermal reaction program of the hydrothermal reactor 3 and the sulfur-based compound oxidation program of the oxidation battery 4 are combined, the positive electrode electrolyte in the first storage tank 12 is purified and restored to the initial state and rated storage capacity, and the equalization system is started to mix the electrolytes in the first storage tank 12 and the second storage tank 13.

[0069] Specifically, the positive electrolyte of the flow battery 1 flows out of the first tank 12, is driven by the equalizing pump, and flows into the second tank 13 through the first pipeline 81. At the same time, the second pipeline 82 is ensured to be conductive, so that the electrolytes in the first tank 12 and the second tank 13 are circulated and mixed. After multiple cycles, the positive and negative electrolytes are evenly mixed. The equalizing system completes the operation.

[0070] Since the positive and negative electrodes of the liquid flow battery 1 are composed of M, N and supporting electrolyte, the supporting electrolyte can be HCl, sulfuric acid, etc., and the positive and negative electrode components in the initial state are the same (that is, the new sulfur-based compound components without charging and discharging are the same), after the sulfur-based hydrothermal reaction program in the hydrothermal reactor 3, the sulfur-based compound oxidation program in the oxidation battery 4, the oxidation battery 4 purification system and the equalization system, the positive and negative electrodes of the liquid flow battery 1 are restored to the initial state, and the performance and capacity of the liquid flow battery 1 are fully restored. During the operation of the liquid flow battery 1, the above sulfur-based hydrothermal reaction program, the sulfur-based compound oxidation program in the oxidation battery 4, and the oxidation battery 4 purification system program can be executed simultaneously. After the execution is completed, the equalization system is executed, and the system and program are as above. After each execution of the above program, the positive and negative electrodes of the liquid flow battery 1 can be restored to the initial state, and the performance and capacity of the liquid flow battery 1 can be fully restored, so that the liquid flow battery 1 can obtain a high number of cycles, high performance, and high capacity of long-term stable operation with automatic control.

[0071] The following is combined with Figure 1 Some specific embodiments of the electrocatalytic hydrogen production and energy storage combined cycle system of the embodiments of the present invention are described in detail.

[0072] The electrocatalytic hydrogen production and energy storage combined cycle system of the embodiment of the present invention includes a liquid flow battery 1, a hydrogen generator 2, a sulfur-based reaction system, an oxidation battery 4 purification system, a balancing system and an energy management and control system.

[0073] 1. Liquid flow battery 1 and its operation method.

[0074] The liquid flow battery 1 includes a battery stack 11, a first storage tank 12 storing a positive electrode electrolyte, and a second storage tank 13 storing a negative electrode electrolyte. The inner cavity of the battery stack 11 is provided with a first positive electrode 14, a first negative electrode 15 and a first ion exchange membrane 16. The first ion exchange membrane 16 divides the inner cavity of the battery stack 11 into a first chamber 17 for arranging the first positive electrode 14 and a second chamber 18 for arranging the first negative electrode 15; the first storage tank 12 is connected to the first chamber 17 and forms a circulation loop so that the positive electrode electrolyte circulates in the first storage tank 12 and the first chamber 17; the second storage tank 13 is connected to the second chamber 18 and forms a circulation loop so that the negative electrode electrolyte circulates in the second storage tank 13 and the second chamber 18.

[0075] The flow battery 1 also includes a pipeline for conveying electrolyte, a pump 91 for driving the electrolyte to flow in the pipeline, a valve 92 for controlling the on-off of the pipeline, a heat exchanger for heating the positive electrolyte and the negative electrolyte, and other components. For example, a first heat exchanger 19 is arranged on the pipeline for allowing the positive electrolyte to flow from the first storage tank 12 to the first chamber 17 and on the pipeline for allowing the negative electrolyte to flow from the second storage tank 13 to the second chamber 18 to adjust the temperature of the electrolyte flowing into the battery stack 11 of the flow battery 1.

[0076] The positive and negative electrolytes of the liquid flow battery system 1 are both composed of electrolyte active material M (n+) (V 4+ , Fe 2+ etc. positive electrode active material ions), N (n+1)+ (V 3+ etc. negative electrode active material ions).

[0077] The positive electrode reaction is M (n+) / M (n+1)+ Oxidation reaction (positive electrode pair includes but is not limited to Fe 2+ / Fe 3+ , M (n+) / C 4+ , V 4+ / V 5+ , where M represents a certain metal ion at the positive electrode as an active substance), and the negative electrode reaction is N (n+1) / N (n+) Reduction reaction (negative electrode pair includes but is not limited to V 3+ / V 2+ , where N represents, where N represents a certain metal ion in the negative electrode as an active substance), the above positive and negative electrode pairs are for illustrating the working principle.

[0078] That is, the electrolyte in the flow battery 1 includes a positive electrode pair, a negative electrode pair and a supporting electrolyte. The supporting electrolyte is an acidic medium composed of HCl, H 2 SO 4 , perchloric acid, nitric acid, methanesulfonic acid or mixed acid, etc., methanesulfonic acid can increase the activity of active substances such as M (n+) and N (n+1)+ Solubility, preferably, the supporting electrolyte is a mixed acid of hydrochloric acid / sulfuric acid / nitric acid+methanesulfonic acid. And the positive and negative electrolytes in the initial state have the same composition (that is, the new electrolytes without charge and discharge have the same composition), and the positive electrode of the constructed battery stack 11 is M (n+) / M (n+1)+ The first positive electrode 14 can be synthesized by chemical vapor deposition (CVD) of TiC / TiO 2 Coated carbon-based electrodes (carbon felt or graphite felt), or carbon-based electrodes with boron-doped titanium dioxide coatings

[0079] (Carbon felt or graphite felt). TiC / TiO 2 Coating and boron-doped titanium dioxide coating effectively reduce the direct contact reaction of carbon-based electrodes in highly oxidizing M-based electrolytes and improve the corrosion resistance of the electrodes.

[0080] The operation process of flow battery 1 is as follows:

[0081] The negative electrode electrolyte of the liquid flow battery 1 flows out from the second storage tank 13, driven by a pump, and passes through a heat exchanger 1 to form the temperature required by the liquid flow battery 1 (for example, the operating temperature is 60 degrees Celsius). When the ambient temperature is low, the heat exchanger heats the electrolyte, and when the battery temperature rises (such as high current density circulation causing the battery to heat up), the heat exchanger cools the electrolyte. The negative electrode electrolyte flows into the battery stack 11 to react.

[0082] The battery stack 11 is the power unit of the flow battery 1, which serves as the core component of energy exchange. The battery stack 11 has multiple battery cells, positive current collectors and negative current collectors. Each battery cell has a first positive electrode 14, a first negative electrode 15 and a first ion exchange membrane 16. The positive current collector and the negative current collector connect multiple battery cells in series to form the battery stack 11. Specifically, the battery stack 11 is composed of one or more battery cells (referred to as single cells) connected in series. The battery cell is composed of positive and negative electrodes, electrolytes and ion exchange membranes separating electrodes, and has a battery assembly with a pair of positive and negative output terminals (bipolar plates or current collectors). When the number of battery cells is ≥1, multiple groups of identical battery cells are connected in series through negative current collectors and positive current collectors to form the battery stack 11. At this time, the negative current collector and the positive current collector are negative bipolar plates and positive bipolar plates, respectively. The positive and negative electrolytes undergo electrochemical redox reactions in the battery stack 11. Electrons flow between the positive and negative electrodes in the battery stack 11 of the liquid flow battery 1 in an external circuit. During the charging process, the renewable energy system 7 generates electricity and supplies power to the liquid flow battery 12, and electrons flow from the positive electrode to the negative electrode in the external circuit.

[0083] During the normal charging process of flow battery 1, constant current or constant power is used to charge from 0V to U 1 (For example, U 1 1 to 1.9V), constant current density = j normal (Can be set from 10 to 300mAcm -2 ). The reactant ions of the positive and negative electrolytes flow inside the battery stack 11 and undergo electrochemical redox reactions on the positive and negative electrodes. The electrochemical reactions of the active materials in the positive and negative half-cells of the battery unit and their energy storage occur simultaneously. During the charging process of the flow battery 1, the positive electrode M (n+) Oxidized to M (n+1)+ , N (n+1)+ Restore to N (n+) , flowing into the first storage tank 12 and the second storage tank 13 for storage respectively.

[0084] During the charging process, the negative electrode electrolyte after the electrochemical reaction flows out of the battery stack 11 and flows into the second storage tank 13 for storage.

[0085] The same is true for the positive side of the main stack 11. The positive electrolyte of the flow battery 1 flows out from the first storage tank 12, is driven by a pump, and passes through the heat exchanger to form the temperature required by the flow battery 1 (for example, the operating temperature of the flow battery 1 is 60 degrees Celsius). When the ambient temperature is low, the heat exchanger heats the electrolyte, and when the battery temperature rises (such as high current density circulation causes the battery to heat up), the heat exchanger cools the electrolyte. The positive electrolyte flows into the stack 11 through the heat exchanger.

[0086] During the charging process, the positive electrode electrolyte after the electrochemical reaction flows out of the battery stack 11 and flows into the first storage tank 12 for storage.

[0087] The discharge process is similar to the charging process, except that the flow battery 1 discharges to the power load. (n+1)+ Restore to M (n+) (e.g. Fe 3+ Reduction to Fe 2+ ), N (n+) Oxidized to N (n+1)+ , reflux to the first storage tank 12 and the second storage tank 13 respectively.

[0088] The battery stack 11 undergoes electrochemical reactions of charging and discharging. At the same time, electrochemical side reactions will inevitably occur under normal operating conditions of the liquid flow battery 1. The side reactions will irreversibly consume electrons, resulting in an imbalance in the charge state of the positive electrode electrolyte and the negative electrode electrolyte (referred to as charge imbalance), and ultimately leading to an imbalance in the capacity of the positive and negative electrodes and a reduction in capacity.

[0089] Liquid flow battery 1, the electrochemical reactions and side reactions of the positive and negative electrodes during the charging process are:

[0090] Positive electrode: M (n+) -e - =M (n+1)+ , x V vs SHE;

[0091] Negative electrode: N (n+1)+ +e - =N (n+) ,y V vs SHE;

[0092] Hydrogen evolution side reaction: 2H + +2e - =H 2 , 0V vs SHE.

[0093] The hydrogen gas released by the hydrogen release side reaction flows into the hydrogen production generator 2 and flows out together with the hydrogen production.

[0094] The electrochemical reactions of the positive and negative electrodes during the discharge process are:

[0095] Positive electrode: M (n+1)+ +e - =M(n+) , x V vs SHE;

[0096] Negative electrode: N (n+) -e - =N (n+1)+ ,y V vs SHE.

[0097] The liquid flow battery 1 can be connected to a renewable energy system to be charged by the renewable energy system. When the renewable energy system has a large output, the renewable energy system can supply power to the power loads such as the sulfur-based reaction system. When the renewable energy system has a small output or it is predicted that the output will be small in the next period, the liquid flow battery 1 can be used to supply power to the power loads.

[0098] 2. The hydrogen generator 2 and the liquid flow battery 1 operate in conjunction.

[0099] The hydrogen generator 2 has a hydrogen production catalytic layer 27 . The hydrogen generator 2 is connected to the second storage tank 13 to form a circulation loop. The negative electrode electrolyte is regenerated in the hydrogen generator 2 and hydrogen is generated in the hydrogen generator 2 .

[0100] A pipeline for conveying electrolyte, a pump for driving the electrolyte to flow in the pipeline, a valve for controlling the on-off of the pipeline and other components are arranged between the hydrogen generator 2 and the second storage tank 13 .

[0101] During the charging / discharging process of the liquid flow battery 1, the loop system between the hydrogen generator 2 and the second storage tank 13 can be started simultaneously or as needed to realize the dual-loop joint operation of the liquid flow battery 1 charging / discharging and the negative electrode electrolyte hydrogen production. By independently operating hydrogen production, the storage capacity of the liquid flow battery 1 is increased, the flexible decoupling operation of hydrogen production and liquid flow battery 1 charging and discharging is realized, and the power supply stability and hydrogen production response speed of renewable energy hydrogen production are also improved.

[0102] The operation method of the loop formed by the hydrogen generator 2 and the second storage tank 13 is as follows:

[0103] During the charging or discharging process of the flow battery 1, the second storage tank 13 contains N (n+) The electrolyte is discharged by entering the second storage tank 13 to produce hydrogen. The hydrogen generator 2 also has a first circulation pump 21, a first heater 22, a first agitator 23 and a first feed port 26. The first circulation pump 21 can drive the liquid in the hydrogen generator 2 to circulate, the first heater 22 can heat the liquid in the hydrogen generator 2, and the first agitator 23 can increase the fluidity of the liquid; the hydrogen generator 2 is connected to a first pressure gauge 24 and a first compressor 25. The hydrogen production catalytic layer includes a first substrate layer and a first catalytic particle. The first substrate layer is carbon felt, graphite felt, titanium mesh, SiO 2 Any one of the particle fixed beds, the first catalytic particle is MoS 2Or Mo 2 C particles. The catalysis, self-circulation and heating of the first circulation pump 21, the first heater 22 and the first agitator 23 can increase the hydrogen production reaction rate. The pressure is monitored by the first pressure gauge 24 and accidental overpressure discharge is performed. The first feed port 26 is used to supplement the medium lost by the hydrogen generator 2 during the hydrogen production process.

[0104] Negative electrolyte hydrogen production reaction equation: 4N (n+) +4H + =2H 2 +4N (n+1)+ , hydrogen production reactant H + From the liquid flow battery 1 during charging, H diffuses across the membrane to the negative electrode of the stack 11. + Flowing into hydrogen generator 2 is reduced to H 2 The battery stack 11 charges the newly generated N (n+1)+ The electrolyte returns to the first storage tank 12 to continue charging the liquid flow battery 1, thereby increasing the storage capacity of the liquid flow battery 1. + Reduced to H 2 , after passing through the first compressor 25, it is supplied to hydrogen users. The hydrogen generator 2 is decoupled from the charge and discharge of the liquid flow battery 1, and the hydrogen generator 2 can operate independently. Since the hydrogen production principle is the discharge of the negative electrode electrolyte, the generated hydrogen has no oxygen impurities and does not need to be purified. According to the needs of hydrogen users, continuous and instant supply can be achieved.

[0105] 3. Sulfur-based reaction system and operation method thereof.

[0106] The sulfur-based reaction system is used to reduce the active substances in the positive electrode electrolyte in the first storage tank 12 and replenish hydrogen ions into the positive electrode electrolyte. The sulfur-based reaction system includes a hydrothermal reactor 3 and an oxidation cell 4. The inner cavity of the hydrothermal reactor 3 has a hydrothermal reaction catalytic layer 31. The inner cavity of the hydrothermal reactor 3 is connected to the first storage tank 12. The positive electrode electrolyte in the first storage tank 12 can be transported into the hydrothermal reactor 3 and react with the sulfur-based compound.

[0107] A high proportion (e.g., 4 / 5 volume ratio) of the positive electrode electrolyte in the first storage tank 12 flows into the hydrothermal reactor 3. A certain amount of sulfur-based compounds are injected into the hydrothermal reactor 3, and the sulfur-based compounds include, but are not limited to, hydrogen sulfide, sulfur dioxide, and other sulfur-based compounds. The molar amount of the sulfur-based compound corresponds to the molar amount of the excess x% M in the positive electrode reduced to M0 (for example, if hydrogen sulfide is used as the sulfur-based compound, the molar ratio of hydrogen sulfide to the excess M in the main system is x 1 =1:2). For example, in the hydrothermal reactor 3, hydrogen sulfide reacts as a strong sulfur-based compound under the action of the catalyst layer: H 2 S+2M=S+2M0+2H +, reducing the excess M in the positive electrode of the main system (the reaction process in the sulfur-based hydrothermal reactor 3 and the sulfur-based compound oxidation process in the oxidation battery 4 reduce the main system x% M in total), and replenishing the main system hydrogen ions H + .

[0108] The hydrothermal reactor 3 has a second feed port 32, which is used to transport sulfur-based compounds to the inner cavity of the hydrothermal reactor 3 so that the sulfur-based compounds undergo an oxidation reaction in the hydrothermal reactor 3; the hydrothermal reactor 3 is connected to a second pressure gauge 33 for detecting the air pressure in the hydrothermal reactor 3, and the inner cavity of the hydrothermal reactor 3 also has a second circulation pump 34, a second heat exchanger 35 and a second agitator 36.

[0109] When a certain proportion (such as 4 / 5 volume ratio) of the positive electrode electrolyte in the first storage tank 12 flows into the hydrothermal reactor 3, the second agitator 36, the second heat exchanger, and the second circulation pump 34 in the hydrothermal reactor 3 are turned on, and the sulfur-based compound (for example, hydrogen sulfide gas) is introduced at a uniform speed through the second feed port 32, so that the positive electrode electrolyte and the sulfur-based compound in the hydrothermal reactor 3 are fully stirred and heat-exchanged (the heat exchanger cools down and controls the temperature of the exothermic reaction in the reactor), and then self-circulate in the hydrothermal reactor 3 driven by the second circulation pump 34, and contact the hydrothermal reaction catalyst layer 31.

[0110] The hydrothermal reaction catalytic layer 31 is a carbon-based catalyst, a metal catalyst or a metal oxide catalyst. Specifically, the hydrothermal reaction catalytic layer 31 is prepared by coating a carbon-based catalyst, a metal catalyst or a metal oxide catalyst with a carbon-based catalyst (carbon felt, graphite felt, activated carbon, etc.) (metal catalysts include but are not limited to transition metal catalysts such as Fe, Zr, Co, Ni, Mn, MOF; metal oxide catalysts include but are not limited to TiO 2 , titanates, etc.; carbon-based catalysts include but are not limited to graphene, graphene oxide, carbon nanotubes, activated carbon, N-doped nanocarbon materials, etc.). The hydrothermal reaction catalytic layer 31 accelerates the reduction reaction of sulfur-based compounds such as hydrogen sulfide and M substances in the positive electrode electrolyte, catalyzes the reduction reaction of M by sulfur-based compounds in the main reaction direction, improves the selectivity of the product S, and inhibits the side reaction, i.e., H 2 S or SO 2 Oxidation reaction, M reduction reaction, and replenishment of hydrogen ions H lost by hydrogen evolution of sulfur-based compounds in the main system + .

[0111] The following describes a specific embodiment:

[0112] When the flow battery 1 uses hydrochloric acid as the supporting electrolyte, the sulfur-based compound hydrogen sulfide can be used to react with M and the total reaction is: H 2 S+2M=S+2M0+2H + , due to H 2S is oxidized to S at a potential of 0.142 V, and M is reduced to M0 at a potential of xV> the reaction potential of sulfur-based compounds. The catalytic layer enhances the kinetics of sulfur-based hydrothermal reactions, so H 2 The reaction between S and M proceeds spontaneously. When the liquid flow battery 1 uses sulfuric acid / sulfuric acid mixed acid / other mixed acid containing sulfuric acid as the supporting electrolyte, sulfur-based compounds SO 2 The oxidation reaction is: SO 2 +2H 2 O-2e - =SO 4 2- +4H + , the M ion reduction reaction is M+e - =M0, total reaction SO 2 +2H 2 O+2M=2M0+SO 4 2- +4H + . SO 2 The oxidation potential is 0.158 V, so under heating, stirring and catalytic conditions, SO 2 The reaction with M can be carried out.

[0113] It is observed that the second pressure gauge 33 of the gas phase space above the hydrothermal reactor 3 shows a pressure P 1 Start to rise (i.e. P 1 The pressure starts to rise from a stable value and the rising rate increases significantly), and then it can be judged that the sulfur-based hydrothermal reaction of reducing part of M to M0 has been completed, and some sulfur-based compounds are still left, so the reaction of the sulfur-based hydrothermal reactor 3 is stopped. Through this pressure criterion, it is judged that the sulfur-based hydrothermal reaction process of the sulfur-based compound reaction system has been completed and the performance of the positive electrode electrolyte has been partially restored.

[0114] By using a sulfur-based hydrothermal reaction, an efficient decomposition reaction of sulfur-based compounds with a catalyst, heating, self-circulation and stirring is achieved, so that most of the M in the positive electrode of the liquid flow battery 1 has been reduced according to the main reaction, which significantly reduces the power consumption required for the subsequent oxidation reaction of the sulfur-based compounds in the oxidation battery 4, reduces the auxiliary energy consumption of the liquid flow battery 1, and improves the overall system efficiency of the liquid flow battery 1.

[0115] The inner cavity of the oxidation cell 4 is provided with a second positive electrode 41, a second negative electrode 42, a reduction catalyst layer 44 and a second ion exchange membrane 43. The second ion exchange membrane 43 divides the inner cavity of the oxidation cell 4 into a third chamber 45 for arranging the second positive electrode 41 and the reduction catalyst layer 44 and a fourth chamber 46 for arranging the second negative electrode 42. The third chamber 45 is connected to the inner cavity of the hydrothermal reactor 3 and the first storage tank 12 so that the solution of the hydrothermal reactor 3 can be transported into the third chamber 45 and the solution in the third chamber 45 can flow back into the first storage tank 12; the fourth chamber 46 is connected to the first storage tank 12 and forms a circulation loop so that the positive electrode electrolyte in the first storage tank 12 circulates in the first storage tank 12 and the fourth chamber 46.

[0116] A third tank 5 is provided on the pipeline for allowing the electrolyte in the third chamber 45 of the oxidation cell 4 to flow to the first tank 12 and on the pipeline for allowing the electrolyte in the fourth chamber 46 of the oxidation cell 4 to flow to the first tank 12, so as to buffer the electrolyte flowing to the first tank 12. A filter 37 is provided on the pipeline for allowing the solution to flow from the hydrothermal reactor 3 to the third chamber 45.

[0117] The hydrothermal reactor 3, the oxidation cell 4 and other components in the sulfur-based reaction system also include pipelines for conveying electrolyte, pumps for driving the electrolyte to flow in the pipelines, valves for controlling the on-off of the pipelines and other components.

[0118] When the sulfur-based hydrothermal reaction process in the hydrothermal reactor 3 is completed, the sulfur-based compound oxidation process in the oxidation battery 4 is carried out in stages. The oxidation battery 4 is charged, and the oxidation battery 4 performs the sulfur-based compound oxidation process, that is, by charging the sulfur-based compound oxidation hydrothermal reactor 3, the remaining sulfur-based compound is reduced, and the excess M in the positive electrode of the main system is reduced (the sulfur-based hydrothermal reaction process and the sulfur-based compound oxidation process reduce the main system x% M in total), and the hydrogen ions H lost by hydrogen evolution in the main system are supplemented. + , sulfur-based compound oxidation cell 4 total reaction: H 2 S+2M=S+2M0+2H + . Wherein S is the positive electrode product of the sulfur-based compound oxidation battery 4, and M0 is the negative electrode product of the sulfur-based compound oxidation battery 4.

[0119] When the flow battery 1 uses hydrochloric acid as the supporting electrolyte, the sulfur-based compound hydrogen sulfide can be used to react with M and the overall reaction is: H 2 S+2M=S+2M0+2H + , due to H 2 S is oxidized to S with a potential of 0.142 V, and M is reduced to M0 with a potential of xV> the reaction potential of the sulfur-based compound. The catalytic layer enhances the kinetics of the sulfur-based hydrothermal reaction, so H 2The reaction potential of S and M is extremely low and close to 0V, and the power consumption for achieving oxidation of sulfur-based compounds (auxiliary energy consumption of liquid flow battery 1) is extremely low. When the liquid flow battery 1 uses sulfuric acid / sulfuric acid mixed acid / other mixed acid containing sulfuric acid as the supporting electrolyte, sulfur-based compounds SO 2 Oxidation reaction SO 2 +2H 2 O-2e - =SO 4 2- +4H + , the M ion reaction is M+e - =M0, total reaction SO 2 +2H 2 O+2M=2M0+SO 4 2- +4H + . SO 2 The oxidation potential is 0.158 V, so SO is catalyzed and oxidized by sulfur-based compounds under the conditions of oxidation. 2 The reaction potential with M is low, and the power consumption for achieving oxidation of sulfur-based compounds (auxiliary energy consumption of flow battery 1) is low.

[0120] The oxidation cell 4 performs a sulfur-based compound oxidation process. In other words, the oxidation cell 4 is charged, and the remaining sulfur-based compounds after the sulfur-based hydrothermal reaction in the sulfur-based hydrothermal reactor 3 are oxidized. At the same time, the excess M in the positive electrode of the main system of the flow battery 1 is reduced, and the main system hydrogen ions H are supplemented. + The oxidation process of sulfur-based compounds. The charging method of oxidation battery 4 is to firstly keep the current density j constant. 2 Charge to USB 2 , and then maintain a constant voltage U 2 The charging continues until the hydrothermal reactor 3 and the first storage tank 12 are emptied. 2 Can be set to 0.1~1V, j 2 Can be set to 1~200mAcm -2 .

[0121] The specific operation method is as follows.

[0122] The negative electrode operation procedure of the sulfur-based compound oxidation battery 4 is as follows:

[0123] The positive electrode electrolyte in the first storage tank 12 of the liquid flow battery 1 passes through the fourth chamber 46 of the oxidation battery 4, and the excess M in the main system is charged at the second negative electrode 42 of the oxidation battery 4 to undergo an electrochemical reaction, and the excess M ions in the main system are reduced to M0; after the reduction is completed, it flows back to the third storage tank 5 for storage. The electrolyte that flows back from the fourth chamber 46 of the oxidation battery 4 to the first storage tank 12 first flows back to the third storage tank 5 for storage. By setting up the third storage tank 5 to cache the positive electrode electrolyte, it is ensured that the inlet concentration of the negative electrode reactant of the sulfur-based compound oxidation battery 4 is the highest (from the positive electrode of the main system of the liquid flow battery 1), which significantly reduces the voltage and energy consumption of the sulfur-based compound oxidation battery 4, and improves the overall system efficiency of the liquid flow battery 1.

[0124] The positive electrode operation procedure of the sulfur-based compound oxidation battery 4 is as follows:

[0125] The mixture of the remaining sulfur-based compound and the positive electrode electrolyte in the hydrothermal reactor 3 flows into the third chamber 45 of the oxidation cell 4 after passing through the filter 37 (filtering the sulfur product of the hydrothermal reactor 3) and the pump, and contacts the second positive electrode 41 and the reduction catalyst layer 44 for electrochemical reaction. The filter 37 is used to collect the catalyst and sulfur that fall off in the hydrothermal reactor 3. The reduction catalyst layer 44 is a carbon-based catalyst, a metal catalyst or a metal oxide catalyst. Specifically, the reduction catalyst layer 44 is prepared by coating a carbon-based catalyst (carbon felt, graphite felt, activated carbon, etc.) with a carbon-based catalyst, a metal catalyst or a metal oxide catalyst (metal catalysts include but are not limited to transition metal catalysts such as Fe, Zr, Co, Ni, Mn, MOF; metal oxide catalysts include but are not limited to TiO 2 , titanates, etc.; carbon-based catalysts include but are not limited to graphene, graphene oxide, carbon nanotubes, activated carbon, N-doped nanocarbon materials, etc.). By designing the reduction catalytic layer 44, the reduction reaction of sulfur-based compounds such as hydrogen sulfide and M can be accelerated, catalyzing the reduction reaction of sulfur-based compounds to M in the main reaction direction, improving the selectivity of the product S, and inhibiting the side reaction, that is, H 2 S or SO 2 Oxidation reaction, M reduction reaction, and replenishment of hydrogen ions H lost by hydrogen evolution of sulfur-based compounds in the main system + The product H + From the second ion exchange membrane 43 to the second negative electrode 42, H + Enter the positive electrolyte of the main system of liquid flow battery 1 to replenish the H lost by the positive electrolyte during the stage of capacity loss caused by hydrogen evolution + .

[0126] After the sulfur-based compound is oxidized, it is stored by flowing back to the third tank 5. In the embodiment of the present invention, the electrolyte that flows back to the first tank 12 from the third chamber 45 of the oxidation cell 4 first flows back to the third tank 5 for storage. The third tank 5 is provided to cache the positive electrode electrolyte after the reaction, thereby ensuring that the positive electrode reactant inlet concentration of the sulfur-based compound oxidation cell 4 is the highest (the remaining sulfur-based compound from the sulfur-based hydrothermal reactor 3), significantly reducing the voltage and energy consumption of the sulfur-based compound oxidation cell 4, and improving the overall system efficiency of the flow battery 1. The solid sulfur produced by the oxidation of the sulfur-based compound is deposited on the second positive electrode 41 of the oxidation cell 4, and the electrolyte after the reaction flows back to the third tank 5. The gas mixture (a small amount of water vapor, hydrogen chloride gas, and incompletely reacted hydrogen sulfide gas) in the gas phase space at the top of the third tank 5 can be discharged through a gas phase pipeline. For example, the gas in the gas phase space at the top of the third tank 5 is transported into an alkali liquid tank through a gas phase pipeline for post-treatment, and the alkali liquid tank can be shared with the fifth tank 7 described below to achieve pollution-free discharge from the external exhaust pipe.

[0127] The electrocatalytic hydrogen production and energy storage combined cycle system of the embodiment of the present invention produces hydrogen by discharging the negative electrode electrolyte, and utilizes a sulfur-based reaction system to achieve performance recovery of the liquid flow battery 1 and replenish hydrogen ions, thereby improving the system efficiency of the liquid flow battery 1 and achieving low auxiliary energy consumption, high storage capacity, and continuous, controllable and efficient hydrogen production.

[0128] After completing the reaction process in the hydrothermal reactor 3 of the sulfurization reaction system and the sulfur-based compound oxidation process in the oxidation cell 4, a recharging process is performed on the battery stack 11 of the flow battery 1:

[0129] The recharging procedure of the battery stack 11 of the flow battery 1 (recharging based on the main system of the flow battery 1 being fully charged) is executed to complete the performance recovery of the flow battery 1. The details are as follows:

[0130] The positive electrode electrolyte in the third tank 5 has completed the first round of reduction, and after being driven by the pump, it flows into the first tank 12. The stack 11 runs the recharging procedure, by executing the constant voltage U 1 Charge to the stack current density ≤ j min , the storage capacity of the liquid flow battery 1 is accumulated during the recharging program stage. If the total storage capacity of the main program charging stage + the recharging stage of the liquid flow battery 1 = the rated value, the program is stopped to complete the performance recovery of the liquid flow battery 1; if it is less than the rated value, the second round of repeating the above sulfur-based hydrothermal reaction and sulfur-based compound oxidation program is started until the performance recovery of the liquid flow battery 1 is completed.

[0131] The specific operation procedures of the positive and negative electrodes of the battery stack 11 of the liquid flow battery 1 are as follows.

[0132] The negative electrode side operation procedure of the stack 11 is as follows:

[0133] The negative electrolyte of the flow battery 1 flows out from the second storage tank 13, is driven by the pump and enters the second chamber 18 after passing through the first heat exchanger 19. The battery stack 11 is 131. The charging power source (renewable energy system or external public grid) has a constant voltage U 1 Charging. The negative electrolyte of the liquid flow battery 1 undergoes an electrochemical reaction through the negative electrode of the battery stack 11, and the negative electrolyte undergoes a reduction reaction at the negative electrode (after the operation of a main system is completed, it is in a fully charged state restricted by the positive electrode, and the negative electrode state is 1-x%N+x%N0, and only 1-x%N0 actually participates in this charging). During the operation phase of the sulfur-based reaction system, the remaining x%N0 continues to undergo a reduction reaction. After the reduction reaction, the negative electrolyte of the liquid flow battery 1 flows back to the second storage tank 13.

[0134] The positive electrode side operation procedure of the stack 11 is as follows:

[0135] The positive electrolyte of the flow battery 1 flows out from the first storage tank 12, is driven by the pump and flows into the first chamber 17 of the battery stack 11 after passing through the heat exchanger. The battery stack 11 is charged by the constant voltage U 1 Charging. The positive electrode electrolyte of the liquid flow battery 1 passes through the first positive electrode 14 of the stack 11, and an electrochemical reaction occurs. The positive electrode undergoes an oxidation reaction at the positive electrode (the liquid flow battery 1 runs, and the positive electrode is 100% M after it is fully charged, of which the excess M ions account for x%. After the above sulfur-based hydrothermal reactor 3 and sulfur-based compound oxidation battery 4 are operated, M is basically all reduced to M0 and flows back to the first storage tank 12). The newly generated M0 of the sulfur-based compound oxidation battery 4 undergoes an oxidation reaction at the positive electrode of the stack 11 and is oxidized to M; N0 in the negative electrode of the stack 11 undergoes a reduction reaction to become N (the remaining N0 in the negative electrode storage tank of the main system accounts for x%). After the oxidation reaction of the positive electrode of the stack 11, the positive electrode electrolyte of the liquid flow battery 1 flows back to the first storage tank 12 through the pipeline.

[0136] After the newly generated M0 is reduced by the sulfur-based hydrothermal reactor 3 and the sulfur-based compound oxidation battery 4 and transported to the stack 11, the positive electrode of the stack 11 continues to undergo the reaction of M0 being oxidized to M. When the hydrothermal reactor 3 and the oxidation battery 4 in the sulfur-based reaction system convert all the excess M (a total of x%) of the flow battery 1 into M0, this part of M0 is completely oxidized to M through the positive electrode of the stack 11; at this time, the remaining x% N0 at the negative electrode of the stack 11 is completely reduced to N. Finally, the positive electrode state is 100% M, and the negative electrode state is 100% N, that is, the flow battery 1 is fully charged, and the capacity of the flow battery 1 is fully restored (both the positive and negative electrodes are SOC = 100%).

[0137] 4. Oxidation battery 4 purification system and its operation method.

[0138] The oxidation battery 4 purification system includes a fourth storage tank 6 for storing a cleaning agent and a fifth storage tank 7 for storing a treatment solvent. The fourth storage tank 6 and the fifth storage tank 7 are both connected to the third chamber 45 and the fourth chamber 46 of the oxidation battery 4. The positive and negative electrodes of the power supply for supplying power to the oxidation battery 4 are reversed. The cleaning agent flowing from the fourth storage tank 6 into the third chamber 45 reacts in the third chamber 45 and then flows into the fifth storage tank 7. The cleaning agent flowing from the fourth storage tank 6 into the fourth chamber 46 reacts in the fourth chamber 46 and then flows into the fifth storage tank 7, so as to purify the oxidation battery 4.

[0139] Furthermore, the processing solvent is an alkaline solution, the cleaning agent is a supporting electrolyte in the electrolyte of the liquid flow battery 1, and an alkali solution pump is provided on the fifth storage tank 7 to drive the alkali solution in the fifth storage tank 7 to self-circulate and spray in the fifth storage tank 7 to improve the processing effect of the gas or liquid entering the fifth storage tank 7.

[0140] During the sulfur-based compound oxidation operation phase of the oxidation cell 4, trace amounts of sulfur solids are deposited on the second positive electrode 41 of the oxidation cell 4, resulting in electrode passivation. During the purification phase, the oxidation cell 11 is charged, and the positive and negative electrodes of the oxidation cell 11 are reversed in polarity (i.e., the positive and negative electrodes are swapped). The cleaning agent in the fourth storage tank 6 is a supporting electrolyte (such as hydrochloric acid, sulfuric acid, etc.), which flows into the third chamber 45 and the fourth chamber 46 of the oxidation cell 11 respectively, and the sulfur solids on the second positive electrode 41 (actually the negative electrode at this time) are dissolved into polysulfide ions S x - The sulfur compound enters the sulfur-based compound and is discharged to the fifth storage tank 7 for treatment or absorption; the hydrochloric acid decomposes into chlorine gas at the second negative electrode 42 (actually the positive electrode at this time) and enters the sulfur-based compound and is discharged to the fifth storage tank 7 for absorption. The sulfur-based compound oxidation battery 4 is charged with a constant current to a charging voltage U 3 A sharp rise with an inflection point U 3B , where U 3B =1.2~1.6V, it means that the trace sulfur solid deposited on the sulfur-based compound oxidation battery 4 has been purified and the passivation problem of the electrode of the sulfur-based compound oxidation battery 4 has been avoided. Since the supporting electrolyte of the flow battery 1 is used as a cleaning agent to avoid the introduction of impurities, the charging is stopped at this time.

[0141] 5. Balancing system and its operation method.

[0142] The balancing system includes a first pipeline 81, a second pipeline 82 and a balancing pump. The first pipeline 81 and the second pipeline 82 are both connected between the first storage tank 12 and the second storage tank 13. The balancing pump is used to drive the electrolyte in the first storage tank 12 to flow from the first pipeline 81 to the second storage tank 13, and to drive the electrolyte in the second storage tank 13 to flow from the second pipeline 82 to the first storage tank 12.

[0143] During the operation of the liquid flow battery 1, part of the ions and water molecules migrate from the negative electrode to the positive electrode through the first ion exchange membrane 16, resulting in an imbalance in the liquid levels of the second storage tank 13 and the first storage tank 12, which in turn leads to a loss of charge and discharge capacity of the liquid flow battery 1. After the sulfur-based hydrothermal reaction program of the hydrothermal reactor 3 and the sulfur-based compound oxidation program of the oxidation battery 4 are combined, the positive electrode electrolyte in the first storage tank 12 is purified and restored to the initial state and rated storage capacity, and the equalization system is started to mix the electrolytes in the first storage tank 12 and the second storage tank 13.

[0144] Specifically, the positive electrolyte of the flow battery 1 flows out of the first tank 12, is driven by the equalizing pump, and flows into the second tank 13 through the first pipeline 81. At the same time, the second pipeline 82 is ensured to be conductive, so that the electrolytes in the first tank 12 and the second tank 13 are circulated and mixed. After multiple cycles, the positive and negative electrolytes are evenly mixed. The equalizing system completes the operation.

[0145] Since the positive and negative electrodes of the liquid flow battery 1 are composed of M, N and supporting electrolyte, the supporting electrolyte can be HCl, sulfuric acid, etc., and the positive and negative electrode components in the initial state are the same (that is, the new sulfur-based compound components without charging and discharging are the same), after the sulfur-based hydrothermal reaction program in the hydrothermal reactor 3, the sulfur-based compound oxidation program in the oxidation battery 4, the oxidation battery 4 purification system and the equalization system, the positive and negative electrodes of the liquid flow battery 1 are restored to the initial state, and the performance and capacity of the liquid flow battery 1 are fully restored. During the operation of the liquid flow battery 1, the above sulfur-based hydrothermal reaction program, the sulfur-based compound oxidation program in the oxidation battery 4, and the oxidation battery 4 purification system program can be executed simultaneously. After the execution is completed, the equalization system is executed, and the system and program are as above. After each execution of the above program, the positive and negative electrodes of the liquid flow battery 1 can be restored to the initial state, and the performance and capacity of the liquid flow battery 1 can be fully restored, so that the liquid flow battery 1 can obtain a high number of cycles, high performance, and high capacity of long-term stable operation with automatic control.

[0146] The trace unreacted gas of the hydrothermal reaction and the oxidation reaction of the sulfur-based compound in the sulfur-based reaction system, the trace water vapor, hydrochloric acid vapor, the sulfur-based compounds generated in the purification system of the oxidation stack 11, and other substances that need to be discharged are respectively transported to the fifth storage tank 7, and are absorbed by the alkaline solution in the fifth storage tank 7 and then discharged to the outside. At the same time, the alkali solution pump configured in the fifth storage tank 7 drives the alkali solution to absorb the remaining tail gas, and the insoluble gas sulfur-based hydrothermal reaction products and the like are discharged to the outside through the external exhaust pipe on the fifth storage tank 7 without pollution.

[0147] The system of the present invention is controlled and operated by the energy management and control system program as a whole. According to each subsystem and its operation program, the program is set up, and the operation control strategy and code are built in to control the charging and discharging and operation of the charging power supply and the power load, as well as the start and stop and operation of the pumps, valves, heat exchangers, heaters and other equipment related to each subsystem.

[0148] The performance recovery method of the electrocatalytic hydrogen production and energy storage combined cycle system based on any one of the above embodiments disclosed in the present invention comprises:

[0149] S101 , conveying part of the positive electrode electrolyte in the first storage tank 12 (for example, a positive electrode electrolyte in a volume ratio of 4 / 5) into the hydrothermal reactor 3 , and starting the hydrothermal reactor 3 .

[0150] S102, a sulfur-based compound (which may be a sulfur-based compound such as hydrogen sulfide gas or sulfur dioxide gas) is introduced into the hydrothermal reactor 3 to reduce the active substances of the positive electrode electrolyte in the hydrothermal reactor 3, and at the same time replenish the hydrogen ions of the flow battery 1. The hydrothermal reaction procedure in the hydrothermal reactor 3 is the same as that in the above embodiment, so it is not repeated here.

[0151] S103, supplying power to the oxidation cell 4, transporting the positive electrode electrolyte in the hydrothermal reactor 3 to the positive electrode of the oxidation cell 4, and transporting part of the positive electrode electrolyte in the first storage tank 12 to the negative electrode of the oxidation cell 4 to reduce the active substances in the positive electrode electrolyte in the oxidation cell 4; the oxidation procedure of the sulfur-based compound in the oxidation cell 4 is the same as that in the above embodiment, so it will not be repeated.

[0152] S104, the electrolyte after the reaction in the oxidation cell 4 is transported into the first storage tank 12. In order to ensure that the concentrations of the positive electrode reactant inlet and the negative electrode reactant inlet of the oxidation cell 4 are the highest, a third storage tank 5 is set to cache the electrode liquid after the positive and negative electrode reactions of the oxidation cell 4 in the third storage tank 5, and then transported into the first storage tank 12 through the third storage tank 5.

[0153] S105, executing a charging procedure for the liquid flow battery 1, and determining whether the performance of the liquid flow battery 1 is restored;

[0154] S106, if not, repeat the above steps. The specific operation steps of steps S105 and S106 are the same as the procedure for recharging the battery stack 11 of the flow battery 1 in the above embodiment (recharging after the main system of the flow battery 1 is fully charged), so they will not be repeated.

[0155] Furthermore, the performance recovery method also includes a purification process, which includes: reversing the positive and negative electrodes of the power supply used to power the oxidation battery 4, and conveying a cleaning agent from the fourth storage tank 6 to the positive and negative electrodes of the oxidation battery 4 to dissolve the solid matter deposited in the oxidation battery 4, and processing the substances discharged from the positive and negative electrodes of the oxidation battery 4.

[0156] Furthermore, the performance recovery method also includes a balancing process, which includes: driving the electrolyte in the first storage tank 12 and the second storage tank 13 to circulate for multiple times so that the electrolyte in the first storage tank 12 and the second storage tank 13 are the same. Specifically, the electrolyte in the first storage tank 12 and the second storage tank 13 circulates for multiple cycles through the first pipeline 81 and the second pipeline 82 driven by a balancing pump so that the material composition of the two is the same. Of course, when executing the balancing process, other systems need to stop running and run separately.

[0157] In the process of executing steps S101 to S106, the reduction system with sulfur-based hydrothermal reaction and sulfur-based compound oxidation and the method for setting the operating program parameters thereof are as follows:

[0158] The running procedure, stop procedure and parameter settings of the sulfur-based hydrothermal reaction in the hydrothermal reactor 3.

[0159] When a certain proportion (such as 4 / 5 volume ratio) of the positive electrode electrolyte in the first storage tank 12 flows into the hydrothermal reactor 3, the second agitator 36, the second heat exchanger 35 (heated to 90 degrees Celsius), and the second circulation pump 34 in the hydrothermal reactor 3 are turned on, and a sulfur-based compound (for example, hydrogen sulfide gas) is introduced at a uniform speed through the second feed port 32, so that the positive electrode electrolyte and the sulfur-based compound in the hydrothermal reactor 3 are fully stirred and heat-exchanged, and then self-circulate in the hydrothermal reactor 3 driven by the second circulation pump 34, and contact the hydrothermal reaction catalyst layer 31.

[0160] The hydrothermal reaction catalytic layer 31 is a carbon-based catalyst, a metal catalyst or a metal oxide catalyst. Specifically, the hydrothermal reaction catalytic layer 31 is prepared by coating a carbon-based catalyst, a metal catalyst or a metal oxide catalyst with a carbon-based catalyst (carbon felt, graphite felt, activated carbon, etc.) (metal catalysts include but are not limited to transition metal catalysts such as Fe, Zr, Co, Ni, Mn, MOF; metal oxide catalysts include but are not limited to TiO 2 , titanates, etc.; carbon-based catalysts include but are not limited to graphene, graphene oxide, carbon nanotubes, activated carbon, N-doped nanocarbon materials, etc.). The hydrothermal reaction catalytic layer 31 accelerates the reduction reaction of sulfur-based compounds such as hydrogen sulfide and M substances in the positive electrode electrolyte, catalyzes the reduction reaction of M by sulfur-based compounds in the main reaction direction, improves the selectivity of the product S, and inhibits the side reaction, i.e., H 2 S or SO 2Oxidation reaction, M reduction reaction, and replenishment of hydrogen ions H lost by hydrogen evolution of sulfur-based compounds in the main system + .

[0161] Through the sulfur-based hydrothermal reaction of the sulfur-based compound, the excess M in the positive electrode of the main system of the liquid flow battery 1 is simultaneously reduced (the sulfur-based hydrothermal reaction process and the sulfur-based compound oxidation process reduce the main system x% M in total), and the main system hydrogen ions H are replenished. + The specific embodiment is: when the liquid flow battery 1 uses hydrochloric acid as the supporting electrolyte, the sulfur-based compound hydrogen sulfide can be used to react with M and the total reaction is: H 2 S+2M=S+2M0+2H + , due to H 2 S is oxidized to S at a potential of 0.142 V, and M is reduced to M0 at a potential of xV> the reaction potential of sulfur-based compounds. The catalytic layer enhances the kinetics of sulfur-based hydrothermal reactions, so H 2 The reaction between S and M proceeds spontaneously. When the liquid flow battery 1 uses sulfuric acid / sulfuric acid mixed acid / other mixed acid containing sulfuric acid as the supporting electrolyte, sulfur-based compounds SO 2 The oxidation reaction is: SO 2 +2H 2 O-2e - =SO 4 2- +4H + , the M ion reduction reaction is M+e - =M0, total reaction SO 2 +2H 2 O+2M=2M0+SO 4 2- +4H + . SO 2 The oxidation potential is 0.158 V, so under heating, stirring and catalytic conditions, SO 2 The reaction with M can be carried out.

[0162] It is observed that the second pressure gauge 33 of the gas phase space above the hydrothermal reactor 3 shows a pressure P 1 Start to rise (i.e. P 1 The pressure starts to rise from a stable value and the rising rate increases significantly), and then it can be judged that the sulfur-based hydrothermal reaction of reducing most of M to M0 has been completed, and some sulfur-based compounds are still left, so the reaction of the sulfur-based hydrothermal reactor 3 is stopped. Through this pressure criterion, it is judged that the sulfur-based hydrothermal reaction process of the sulfur-based compound reaction system has been completed and the performance of the positive electrode electrolyte has been partially restored.

[0163] The running program, stopping program and parameter setting of the oxidation reaction of the sulfur-based compound in the oxidation cell 4.

[0164] When the sulfur-based hydrothermal reaction process in the hydrothermal reactor 3 is completed, the sulfur-based compound oxidation process in the oxidation battery 4 is carried out in stages. The oxidation battery 4 is charged, and the oxidation battery 4 performs the sulfur-based compound oxidation process, that is, by charging the sulfur-based compound oxidation hydrothermal reactor 3, the remaining sulfur-based compound is reduced, and the excess M in the positive electrode of the main system is reduced (the sulfur-based hydrothermal reaction process and the sulfur-based compound oxidation process reduce the main system x% M in total), and the hydrogen ions H lost by hydrogen evolution in the main system are supplemented. + , sulfur-based compound oxidation cell 4 total reaction: H 2 S+2M=S+2M0+2H + . Wherein S is the positive electrode product of the sulfur-based compound oxidation battery 4, and M0 is the negative electrode product of the sulfur-based compound oxidation battery 4.

[0165] When the flow battery 1 uses hydrochloric acid as the supporting electrolyte, the sulfur-based compound hydrogen sulfide can be used to react with M and the overall reaction is: H 2 S+2M=S+2M0+2H + , due to H 2 S is oxidized to S with a potential of 0.142 V, and M is reduced to M0 with a potential of xV> the reaction potential of the sulfur-based compound. The catalytic layer enhances the kinetics of the sulfur-based hydrothermal reaction, so H 2 The reaction potential of S and M is extremely low and close to 0V, and the power consumption for achieving oxidation of sulfur-based compounds (auxiliary energy consumption of liquid flow battery 1) is extremely low. When the liquid flow battery 1 uses sulfuric acid / sulfuric acid mixed acid / other mixed acid containing sulfuric acid as the supporting electrolyte, sulfur-based compounds SO 2 Oxidation reaction SO 2 +2H 2 O-2e - =SO 4 2- +4H + , the M ion reaction is M+e - =M0, total reaction SO 2 +2H 2 O+2M=2M0+SO 4 2- +4H + . SO 2 The oxidation potential is 0.158 V, so SO is catalyzed and oxidized by sulfur-based compounds under the conditions of oxidation. 2 The reaction potential with M is low, and the power consumption for achieving oxidation of sulfur-based compounds (auxiliary energy consumption of flow battery 1) is low.

[0166] In specific applications, the oxidation cell 4 has different battery structure designs, different sulfur-based compound concentrations, different sulfur-based compounds (such as hydrogen sulfide and sulfur dioxide), different catalysts, and the reduction catalyst layer 44 is composed of a carbon-based substrate.

[0167] (carbon felt, graphite felt, activated carbon, etc.) coated with metal catalysts or metal oxide catalysts or carbon-based catalysts (metal catalysts include but are not limited to transition metal catalysts such as Fe, Zr, Co, Ni, Mn, MOF; metal oxide catalysts include but are not limited to TiO 2 , titanate, etc.; carbon-based catalysts include but are not limited to graphene, graphene oxide, carbon nanotubes, activated carbon, B / N element-doped nanocarbon materials, etc.), different electrodes (carbon-based, graphite-based, titanium-based), etc., constant voltage charging voltage U 2 and current density j 2 The setting value is different. The charging method of the oxidation battery 4 is to firstly keep the current density j constant. 2 Charge to USB 2 , and then maintain a constant voltage U 2 The charging continues until the hydrothermal reactor 3 and the first storage tank 12 are emptied. 2 Can be set to 0.1~1V, j 2 Can be set to 1~200mAcm -2 .

[0168] Flow battery 1 recharging operation procedure, charging stop procedure and parameter settings.

[0169] After completing the reaction process in the hydrothermal reactor 3 of the sulfurization reaction system and the sulfur-based compound oxidation process in the oxidation cell 4, a recharging process is performed on the battery stack 11 of the flow battery 1:

[0170] The recharging procedure of the battery stack 11 of the flow battery 1 (recharging based on the main system of the flow battery 1 being fully charged) is executed to complete the performance recovery of the flow battery 1. The details are as follows:

[0171] The positive electrode in the third tank 5 has completed the first round of reduction and flows into the first tank 12 after being driven by the pump. The stack 11 runs the recharging program, and the charging power source performs a constant voltage U 1 Charge until the stack 11 reaches the cut-off current density limit, that is, the current density ≤j min And the main system power storage performance is restored to the rated value. Specifically: the battery stack 11 is maintained at U 1 Constant voltage charging, the charging current first increases and then decreases until the current density ≤ j min And it no longer changes, and the main system power storage performance is restored to the rated value. The recharging procedure accumulates the power storage capacity of the flow battery 1. If the total power storage capacity of the main procedure charging stage + the recharging stage of the flow battery 1 = the rated value, the recharging procedure is stopped, indicating that the performance recovery of the flow battery 1 has been completed; if it is less than the rated value, the second round of repeating the above sulfur-based hydrothermal reaction and sulfur-based compound oxidation procedure is started until the performance recovery of the flow battery 1 is completed.

[0172] Depending on the design of the battery stack 11 of the flow battery 1, the selection of sulfur-based compounds / catalysts / electrodes, etc., the charging voltage U 1 and current density limit j min The setting values ​​are different.

[0173] As an example, U 1 Can be set to 1.2~1.4V, j min Can be set to 1~10mAcm -2 .

[0174] The sulfur-based reaction system is in operation phase, that is, the charging power is maintained at U1 to the battery stack 11 of the flow battery 1. 1 The constant voltage charging operation phase, until the current density of the battery stack 11 ≤ j min At the same time, when the system power storage performance of the liquid flow battery 1 is restored to the rated value, it means that the reduction process of the redundant M in the main system is completed, then the charging power supply for the oxidation battery 4 stops charging, and the sulfur-based hydrothermal reaction and sulfur-based compound oxidation reaction of the sulfur-based reaction system are terminated.

[0175] The above stop procedure indicates that the operation of the sulfur-based compound reaction system has been completed and the recharging of the main system of the flow battery 1 has been completed.

[0176] Through the sulfur-based hydrothermal reaction running program, stop program and parameter setting; sulfur-based compound oxidation reaction running program, stop program and parameter setting; liquid flow battery 1 recharging running program, charging stop program and parameter setting. According to the above parameters and criteria, program running and stop instructions are issued. It can be quantitatively judged that the performance recovery of liquid flow battery 1 is completely completed. The above system and program design reduces the complexity, power consumption and cost of the capacity and performance recovery subsystem of liquid flow battery 1 with sulfur-based hydrothermal reaction and sulfur-based compound oxidation to the lowest possible level, thereby improving the overall system efficiency of liquid flow battery 1.

[0177] In practical applications, the operation of the sulfur-based reaction system and its stop procedures and parameter settings can automatically continue the reaction and terminate according to the criteria, complete the complete recovery of the oxidation charge state of the sulfur-based compounds at the positive electrode of the liquid flow battery 1, and effectively reduce the complexity and cost of the performance recovery subsystem of the liquid flow battery 1. Since the acidic sulfur-based compounds (such as hydrochloric acid and sulfuric acid) with the same supporting electrolyte as the main system are used, the sulfur-based compounds are oxidized and react with the positive electrode electrolyte, and the only product is the H originally lost by the system. + , the reactant active substance Mx of the sulfur-based compound, and the solid sulfur that is easily filtered and separated. The reactants and liquid products are all substances in the liquid flow battery 1, and no additional pollution or toxic substances are generated to the liquid flow battery 1.

[0178] The sulfur-based reaction system has the advantages of simple operation, low cost, extremely low voltage, automatic continuous reaction and stop, quantifiable performance recovery endpoint, automatic termination of charge and discharge procedures according to the judgment criteria, and extremely low power consumption (M reduction in H2 The sulfur-based hydrothermal reaction stage is basically completed, and the electrochemical reaction overpotential is low), the solid sulfur produced by the sulfur-based reaction is easy to separate, or the produced sulfuric acid is used as a supporting sulfur-based compound. In addition, the subsystem of the embodiment of the present invention is mainly a closed-loop liquid flow battery design, which can be applied to other aqueous liquid flow batteries.

[0179] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0180] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0181] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0182] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0183] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An electrocatalytic hydrogen production and energy storage combined cycle system, characterized in that: include: A liquid flow battery, the liquid flow battery comprising a battery stack, a first storage tank storing a positive electrode electrolyte, and a second storage tank storing a negative electrode electrolyte, wherein the inner cavity of the battery stack comprises a first positive electrode, a first negative electrode, and a first ion exchange membrane, wherein the first ion exchange membrane divides the inner cavity of the battery stack into a first chamber for arranging the first positive electrode and a second chamber for arranging the first negative electrode; the first storage tank is connected to the first chamber and forms a circulation loop so that the positive electrode electrolyte circulates in the first storage tank and the first chamber; the second storage tank is connected to the second chamber and forms a circulation loop so that the negative electrode electrolyte circulates in the second storage tank and the second chamber; A hydrogen generator, wherein the hydrogen generator has a hydrogen production catalytic layer, the hydrogen generator is connected to the second storage tank to form a circulation loop, the negative electrode electrolyte is regenerated in the hydrogen generator and hydrogen is produced in the hydrogen generator; A sulfur-based reaction system, the sulfur-based reaction system is used to reduce the active material in the positive electrode electrolyte in the first storage tank and replenish hydrogen ions in the positive electrode electrolyte. The sulfur-based reaction system includes a hydrothermal reactor and an oxidation cell. The inner cavity of the hydrothermal reactor has a hydrothermal reaction catalyst layer, and the inner cavity of the hydrothermal reactor is connected with the first storage tank. The positive electrode electrolyte in the first storage tank can be transported into the hydrothermal reactor and react with sulfur-based compounds; the inner cavity of the oxidation cell has a second positive electrode, a second negative electrode, a reduction catalyst layer and a second ion exchange membrane, and the second ion exchange membrane divides the inner cavity of the oxidation cell into a third chamber for arranging the second positive electrode and the reduction catalyst layer and a fourth chamber for arranging the second negative electrode. The third chamber is connected with the inner cavity of the hydrothermal reactor and the first storage tank so that the solution of the hydrothermal reactor can be transported into the third chamber and the solution in the third chamber can flow back to the first storage tank; the fourth chamber is connected with the first storage tank and forms a circulation loop so that the positive electrode electrolyte in the first storage tank circulates in the first storage tank and the fourth chamber.

2. The electrocatalytic hydrogen production and energy storage combined cycle system according to claim 1, characterized in that: The sulfur-based reaction system also includes a third tank, which is provided on a pipeline for allowing the electrolyte in the third chamber of the oxidation cell to flow to the first tank and on a pipeline for allowing the electrolyte in the fourth chamber of the oxidation cell to flow to the first tank, so as to store the electrolyte flowing to the first tank.

3. The electrocatalytic hydrogen production and energy storage combined cycle system according to claim 1, characterized in that: In an initial state, the positive electrode electrolyte and the negative electrode electrolyte in the liquid flow battery are the same, and the supporting electrolytes of the positive electrode electrolyte and the negative electrode electrolyte in the liquid flow battery are acidic media and at least include methanesulfonic acid; And / or, the first positive electrode is a carbon-based electrode with a TiC / TiO2 coating synthesized by chemical vapor deposition, or a carbon-based electrode with a boron-doped titanium dioxide coating; And / or, the battery stack comprises a plurality of battery cells, a positive current collector plate and a negative current collector plate, each of the battery cells comprises the first positive electrode, the first negative electrode and the first ion exchange membrane, and the positive current collector plate and the negative current collector plate connect the plurality of battery cells in series to form the battery stack; And / or, it also includes a first heat exchanger, which is arranged on a pipeline for allowing the positive electrode electrolyte to flow from the first storage tank to the first chamber and on a pipeline for allowing the negative electrode electrolyte to flow from the second storage tank to the second chamber.

4. The electrocatalytic hydrogen production and energy storage combined cycle system according to claim 1, characterized in that: The hydrogen production catalytic layer includes a first base layer and first catalytic particles, the first base layer is any one of carbon felt, graphite felt, titanium mesh, and a fixed bed of SiO2 particles, and the first catalytic particles are MoS2 or Mo2C particles.

5. The electrocatalytic hydrogen production and energy storage combined cycle system according to claim 4, characterized in that: The hydrogen generator also has a first circulation pump, a first heater, a first agitator and a first feed inlet; And / or, the hydrogen production generator is connected to a first pressure gauge and a first compressor.

6. The electrocatalytic hydrogen production and energy storage combined cycle system according to claim 1, characterized in that: The hydrothermal reaction catalytic layer and the reduction catalytic layer are both carbon-based catalysts, metal catalysts or metal oxide catalysts; And / or, the hydrothermal reactor has a second feed port, and the second feed port is used to transport the sulfur-based compound to the inner cavity of the hydrothermal reactor so that the sulfur-based compound undergoes an oxidation reaction in the hydrothermal reactor; And / or, further comprising a second pressure gauge, the second pressure gauge being connected to the hydrothermal reactor and used to detect the gas pressure in the hydrothermal reactor, the inner cavity of the hydrothermal reactor also comprising a second circulation pump, a second heat exchanger and a second agitator; And / or, it also includes a filter, which is arranged on the pipeline used to allow the solution to flow from the hydrothermal reactor to the third chamber.

7. The electrocatalytic hydrogen production and energy storage combined cycle system according to any one of claims 1 to 6, characterized in that: It also includes an oxidation battery purification system, which includes a fourth tank for storing a cleaning agent and a fifth tank for storing a processing solvent, the fourth tank and the fifth tank are both connected to the third chamber and the fourth chamber of the oxidation battery, and the positive and negative electrodes of the power supply for supplying power to the oxidation battery are reversed, and the cleaning agent flowing from the fourth tank into the third chamber reacts in the third chamber and then flows into the fifth tank, and the cleaning agent flowing from the fourth tank into the fourth chamber reacts in the fourth chamber and then flows into the fifth tank, so as to purify the oxidation battery.

8. The electrocatalytic hydrogen production and energy storage combined cycle system according to claim 7, characterized in that: The processing solvent is an alkaline solution, the cleaning agent is a supporting electrolyte in the electrolyte of the liquid flow battery, and an alkali solution pump is provided on the fifth storage tank. The alkali solution pump is used to drive the alkali solution in the fifth storage tank to self-circulate and spray in the fifth storage tank.

9. The electrocatalytic hydrogen production and energy storage combined cycle system according to any one of claims 1 to 6, characterized in that: It also includes a balancing system, which includes a first pipeline, a second pipeline and a balancing pump, the first pipeline and the second pipeline are both connected between the first storage tank and the second storage tank, and the balancing pump is used to drive the electrolyte in the first storage tank to flow from the first pipeline to the second storage tank, and to make the electrolyte in the second storage tank flow from the second pipeline to the first storage tank.

10. A performance recovery method for the electrocatalytic hydrogen production and energy storage combined cycle system according to any one of claims 1 to 9, characterized in that: The performance recovery method comprises: S101, transporting part of the cathode electrolyte in the first storage tank into the hydrothermal reactor, and starting the hydrothermal reactor; S102, introducing a sulfur-based compound into the hydrothermal reactor to reduce the active substances in the positive electrode electrolyte in the hydrothermal reactor; S103, supplying power to the oxidation battery, delivering the positive electrode electrolyte in the hydrothermal reactor to the positive electrode of the oxidation battery, and delivering part of the positive electrode electrolyte in the first storage tank to the negative electrode of the oxidation battery to reduce the active substance of the positive electrode electrolyte in the oxidation battery; S104, transporting the electrolyte after the reaction in the oxidation cell into the first storage tank; S105, executing a recharging procedure on the liquid flow battery, and determining whether the performance of the liquid flow battery is restored; S106: If not, repeat the above steps.

11. The performance restoration method according to claim 10, characterized in that: Step S103 of supplying power to the oxidation battery includes: supplying power at 1 mA cm -2 Up to 200mAcm -2 The oxidation battery is charged to U2 by sealing with a constant current, and then the constant voltage U2 is maintained to continue charging until the electrolyte in the hydrothermal reactor and the first storage tank is emptied, wherein U2 = 0.1V to 1V; And / or, steps S105 and S106 include: maintaining the battery stack of the flow battery at a constant voltage of 1.2V to 1.4V, and increasing and then decreasing the charging current until the current density is less than or equal to 1 mA cm -2 Up to 10mAcm -2 and does not change, determining whether the total storage capacity of the liquid flow battery reaches the rated value, if so, the performance of the liquid flow battery is restored; if not, repeating steps S101 to S105 until the performance of the liquid flow battery is restored; And / or, further comprising a purification process, the purification process comprising: reversing the positive electrode and the negative electrode of the power supply for supplying power to the oxidation battery, delivering a cleaning agent from the fourth storage tank to the positive electrode and the negative electrode of the oxidation battery to dissolve the solid matter deposited in the oxidation battery, and treating the matter discharged from the positive electrode and the negative electrode of the oxidation battery; And / or, it also includes a balancing process, which includes: driving the electrolyte in the first storage tank and the second storage tank to circulate multiple times to make the electrolyte in the first storage tank and the second storage tank the same.

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