Hydrogen energy storage power generation system and power generation method thereof

Abstract

The invention discloses a hydrogen energy storage power generation system and a power generation method thereof. The power generation system comprises an electric energy supply unit, a power grid unit, an electrolyzed water unit, a fuel cell unit and a pure water unit, wherein the electric energy supply unit is connected with the electrolyzed water unit and is used for supplying electric energy which is generated by the electric energy supply unit and cannot be absorbed by a power grid to the electrolyzed water unit for electrolyzing water to prepare hydrogen and oxygen; the electrolyzed water unit is connected with the fuel cell and is used for providing hydrogen and oxygen prepared by the electrolyzed water unit to the fuel cell unit as reaction raw materials; when the electric energy supply unit cannot meet the requirements of the power grid unit, the fuel cell unit supplies electric energy generated by the fuel cell unit to the power grid unit; and the pure water unit is used for recycling water generated by the fuel cell unit and providing electrolyte water for the electrolyzed water unit. The oxygen content of the cathode reaction gas of the fuel cell unit is improved by comprehensively utilizing oxygen generated by electrolyzed water, so that the efficiency of the hydrogen energy storage power generation system is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen energy storage, and relates to a hydrogen energy storage power generation system and a power generation method thereof. Background Art

[0002] Hydrogen energy storage technology refers to an energy storage method that converts electric power into hydrogen for storage and then converts hydrogen into electric power when needed. Hydrogen energy storage technology has the advantages of high energy storage density, flexible storage method, and only water as the product, which is environmentally friendly.

[0003] Currently, hydrogen energy storage mainly converts electrical energy into hydrogen through electrolysis of water, with an efficiency of about 70 - 85%. When generating electricity, hydrogen energy is converted into electrical energy through a fuel cell. Hydrogen is introduced into the anode of the fuel cell and air is introduced into the cathode, with a power generation efficiency of about 45 - 55%. The overall hydrogen energy storage efficiency is low, and in most cases, oxygen is also discharged as a by-product, resulting in insufficient utilization of resources. Summary of the Invention

[0004] In view of this, the present invention provides a hydrogen energy storage power generation system and a power generation method thereof, which comprehensively utilize the oxygen generated by electrolysis of water to increase the oxygen content in the cathode reaction gas of the fuel cell, thereby improving the efficiency of the hydrogen energy storage power generation system.

[0005] To achieve the above object, the present invention adopts the following technical solutions.

[0006] According to the first aspect of the present invention, a hydrogen energy storage power generation system is provided. The hydrogen energy storage power generation system includes an electric energy supply unit, a power grid unit, an electrolyzed water unit, a fuel cell unit, and a pure water unit; wherein,

[0007] The electric energy supply unit is connected to the power grid unit and is used to supply electric energy to the power grid;

[0008] The electric energy supply unit is connected to the electrolyzed water unit and is used to supply the electric energy generated by the electric energy supply unit to the electrolyzed water unit for electrolysis of water to produce hydrogen and oxygen;

[0009] The electrolyzed water unit is connected to the fuel cell and is used to supply the hydrogen and oxygen produced by the electrolyzed water unit to the fuel cell for an electrochemical reaction to convert chemical energy into electric energy;

[0010] The fuel cell is connected to the power grid unit and is used to supply the electric energy generated by the fuel cell to the power grid;

[0011] The pure water unit is connected to one side electrode of the electrolyzed water unit and is used to supply electrolyzed water for the electrolyzed water unit.

[0012] The above hydrogen energy storage power generation system, wherein the fuel cell unit includes a fuel cell stack module, an anode circulation ejector module, an oxygen ejector module, a fuel cell air outlet gas-liquid separator module, and a gas storage tank; among them, the fuel cell stack module is used to convert the chemical energy generated by the electrochemical reaction of hydrogen and oxygen into electrical energy; the anode side outlet of the fuel cell stack module, the ejector fluid inlet of the anode circulation ejector module, the outlet of the anode circulation ejector module, and the anode side inlet of the fuel cell stack module are connected in sequence; the working fluid inlet of the anode circulation ejector module is connected to the hydrogen outlet of the electrolysis water unit; the working fluid inlet of the oxygen ejector module is connected to the oxygen outlet of the electrolysis water unit, the ejector fluid inlet is introduced with purified air, and the outlet is connected to the gas storage tank and the cathode side inlet of the fuel cell stack module in sequence; the fuel cell air outlet gas-liquid separator module is connected to the cathode side air outlet of the fuel cell stack module, and is used to perform gas-liquid separation on the gas mixture generated on the cathode side of the fuel cell stack module. The obtained liquid is water and is stored in the pure water unit, and the obtained gas is discharged from the hydrogen energy storage power generation system.

[0013] In the present invention, in the ejector module, the fluid with a higher pressure is defined as the working fluid, which flows out of the nozzle at a very high speed, entrains the surrounding fluid and undergoes momentum exchange, and the fluid with a lower pressure that is sucked away is the ejector fluid.

[0014] The above hydrogen energy storage power generation system, preferably, when the electrical energy generated by the electrical energy supply unit is greater than the electrical energy required by the power grid, the electrical energy that cannot be consumed by the power grid is provided to the electrolysis water unit for electrolysis to produce hydrogen and oxygen.

[0015] The above hydrogen energy storage power generation system, preferably, when the electrical energy supplied by the electrical energy supply unit cannot meet the demand of the power grid, the fuel cell is connected to the power grid unit and is used to supply the electrical energy generated by the fuel cell to the power grid.

[0016] The above hydrogen energy storage power generation system, preferably, the electrical energy supply unit includes a power station and a voltage conversion module; among them, the voltage conversion module converts the electrical energy generated by the power station and supplies it to users (for example, the power grid or the electrolysis water unit).

[0017] The above hydrogen energy storage power generation system, preferably, the power station includes at least one of a thermal power station and a renewable energy power station.

[0018] The above hydrogen energy storage power generation system, preferably, the power station is a renewable energy power station.

[0019] The above hydrogen energy storage power generation system, preferably, the electrolytic water unit includes an electrolytic cell, a hydrogen separation and purification module, a hydrogen storage module, an oxygen separation and purification module, and an oxygen storage module. Among them, the electrolytic cell is used for electrolyzing water to produce hydrogen and oxygen.

[0020] The above hydrogen energy storage power generation system, preferably, the hydrogen separation and purification module is connected to the cathode side of the electrolytic cell, and is used for separating the gas discharged from the cathode side outlet of the electrolytic cell to obtain hydrogen and water vapor; the separated hydrogen enters the hydrogen storage module for storage; the separated water vapor enters the pure water tank for storage.

[0021] The above hydrogen energy storage power generation system, preferably, the oxygen separation and purification module is connected to the anode side of the electrolytic cell, and is used for separating the gas discharged from the anode side outlet of the electrolytic cell to obtain oxygen and water vapor; the separated oxygen enters the oxygen storage module for storage; the separated water vapor enters the pure water tank for storage.

[0022] The above hydrogen energy storage power generation system, preferably, the fuel cell stack module is connected to the power grid via a voltage conversion unit, and is used for supplying the electric energy generated by the fuel cell stack module to the power grid.

[0023] The above hydrogen energy storage power generation system, preferably, on the pipeline connecting the anode side outlet of the fuel cell stack module and the injection fluid inlet of the anode circulation ejector module, an anode tail gas discharge module is further provided; the anode tail gas discharge module includes one inlet and two outlets, the two outlets are respectively a tail gas discharge outlet and a hydrogen outlet, the inlet of the anode tail gas discharge module is connected to the anode side outlet of the fuel cell stack module, and the hydrogen outlet is connected to the injection fluid inlet of the anode circulation ejector module. The anode tail gas discharge module is used for regularly discharging (through the tail gas discharge outlet) the gas mixture generated on the anode side of the fuel cell stack module to prevent the enrichment of impurity gases. When not discharged, the generated hydrogen is discharged through the hydrogen outlet and enters the anode circulation ejector module for standby, and the regularly discharged tail gas is discharged from the hydrogen energy storage power generation system.

[0024] The above hydrogen energy storage power generation system, preferably, a first flow path and a second flow path are formed by the hydrogen storage module in the electrolytic water unit, the anode circulation ejector module in the fuel cell unit, the anode tail gas discharge module and the anode circulation ejector module on the anode side of the fuel cell stack module; where the first flow path is formed by sequentially connecting the hydrogen storage module, the anode circulation ejector module, and the anode side inlet of the fuel cell stack module, and is used for injecting the hydrogen prepared by the electrolytic cell to the anode of the fuel cell stack module as a hydrogen raw material for an electrochemical reaction.

[0025] The second flow path is formed by connecting the anode side of the fuel cell stack module, the anode tail gas discharge module, and the anode circulation ejector module in sequence, and is used to recover the unreacted hydrogen discharged from the anode side of the fuel cell stack module to the anode circulation ejector module for being ejected again to the anode side of the fuel cell stack module for reuse.

[0026] The first flow path and the second flow path together realize the recycling of hydrogen in the fuel cell unit.

[0027] In the above hydrogen energy storage power generation system, preferably, the oxygen storage module in the electrolyzed water unit is connected to the oxygen ejector module in the fuel cell unit and the cathode side inlet of the fuel cell stack module, and is used to eject the oxygen generated by the electrolyzed water unit to the cathode side of the fuel cell stack module for reaction.

[0028] In the above hydrogen energy storage power generation system, preferably, the fuel cell unit further includes an oxygen pressure regulating module; the oxygen storage module in the electrolyzed water unit and the oxygen ejector module in the fuel cell unit are connected via the oxygen pressure regulating module, and are used to regulate the pressure of the oxygen gas flow in the pipeline.

[0029] In the above hydrogen energy storage power generation system, preferably, the fuel cell unit further includes a back pressure valve;

[0030] The back pressure valve is arranged between the fuel cell air outlet gas-liquid separator module and the cathode side outlet of the fuel cell stack module, and the pressure of the cathode side of the fuel cell stack is controlled by the back pressure valve.

[0031] In the above hydrogen energy storage power generation system, preferably, the pure water unit includes a pure water tank, a pure water pump, a water supply module, and a pure water production module, and the pure water unit is used to prepare and collect the water generated by the fuel cell for electrolysis.

[0032] Wherein, the pure water production module is used to produce water; the pure water unit is connected to the cathode side of the fuel cell unit and is used to collect the water generated by the fuel cell unit.

[0033] In the above hydrogen energy storage power generation system, preferably, it further includes a waste heat recovery unit, and the waste heat recovery unit is respectively connected to the electrolyzed water unit and the fuel cell unit, and is used to recover the waste heat generated by the electrolyzed water unit and the waste heat generated by the fuel cell unit.

[0034] The above hydrogen energy storage power generation system, preferably, the waste heat recovery unit includes an electrolyzed water heat exchange unit and a fuel cell cooling module. Among them, the electrolyzed water heat exchange unit is connected to the oxygen separation and purification module and the pure water tank, and is used to recover the waste heat generated by the electrolyzed water unit; the fuel cell cooling module is respectively connected to the coolant inlet and outlet of the fuel cell stack module, and is used to recover the waste heat generated by the fuel cell unit.

[0035] According to a second aspect of the present invention, there is provided a hydrogen energy storage power generation method, and the power generation method uses any one of the above hydrogen energy storage power generation systems for power generation.

[0036] In the present invention, without conflict, the above technical features can be freely combined to form a new technical solution.

[0037] The above technical solution provided by the present invention has the following advantages compared with the prior art:

[0038] (1) The present invention uses the oxygen generated by electrolyzing water to increase the oxygen content in the cathode reaction gas of the fuel cell, thereby improving the performance of the fuel cell and avoiding waste of oxygen evacuation.

[0039] (2) The present invention uses an oxygen ejector to eject and mix normal-pressure purified air and introduce it into the gas storage tank, which can keep the gas storage tank under pressure and directly introduce it into the fuel cell stack. Therefore, the use of an air compressor can be avoided, thereby making full use of the oxygen pressure potential energy and improving the overall efficiency of the system; by comprehensively using the oxygen generated by electrolyzing water, the present invention can increase the oxygen content of the cathode reaction gas, and the power generation efficiency of the fuel cell can reach 50-65%.

[0040] (3) By connecting the cathode side of the fuel cell to the pure water unit, the present invention can recover the water generated by the fuel cell for use in the electrolysis unit for hydrogen production, avoiding waste of water resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings here are incorporated into the specification and constitute a part of this specification, showing embodiments in line with the present invention, and are used together with the specification to explain the principles of the present invention.

[0042] Figure 1 It is a schematic structural diagram of a hydrogen energy storage power generation system in a preferred embodiment of the present invention.

[0043] The markings are as follows: 1 - renewable energy power station, 2 - voltage conversion module, 3 - electrolyzer, 4 - oxygen separation and purification module, 5 - hydrogen separation and purification module, 6 - pure water pump, 7 - pure water tank, 8 - electrolyzed water heat exchange unit, 9 - oxygen storage module, 10 - hydrogen storage module, 11 - water supply module, 12 - pure water production module, 13 - anode circulation ejector module, 14 - anode tail gas discharge module, 15 - fuel cell stack module, 16 - power grid, 17 - fuel cell air outlet gas-liquid separator module, 18 - back pressure valve, 19 - oxygen ejector module, 20 - gas storage tank, 21 - voltage conversion unit, 22 - oxygen pressure regulation module, and 24 - fuel cell cooling module. Detailed implementation manners

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] Figure 1 A schematic structural diagram of a hydrogen energy storage power generation system according to the first aspect of the present invention is schematically shown. As Figure 1 shown, according to the first aspect of the present invention, a hydrogen energy storage power generation system is provided, and the hydrogen energy storage power generation system includes an electric energy supply unit, a power grid unit, an electrolyzed water unit, a fuel cell unit, and a pure water unit; wherein,

[0046] The electric energy supply unit is connected to the power grid unit and is used to supply electric energy to the power grid;

[0047] The electric energy supply unit is connected to the electrolyzed water unit and is used to supply the electric energy generated by the electric energy supply unit to the electrolyzed water unit for electrolysis of water to produce hydrogen and oxygen;

[0048] The electrolyzed water unit is connected to the fuel cell and is used to supply the hydrogen and oxygen produced by the electrolyzed water unit to the fuel cell for reaction to convert chemical energy into electric energy;

[0049] The fuel cell unit includes a fuel cell stack module 15, an anode circulation ejector module 13, an oxygen ejector module 19, a fuel cell air outlet gas-liquid separator module 17, and a gas storage tank 20; the fuel cell stack module 15 is used to convert the chemical energy generated by the reaction of hydrogen and oxygen into electrical energy; the anode side outlet of the fuel cell stack module 15, the ejector fluid inlet of the anode circulation ejector module 13, the outlet of the anode circulation ejector module 13, and the anode side inlet of the fuel cell stack module 15 are connected in sequence; the working fluid inlet of the anode circulation ejector module 13 is connected to the hydrogen outlet of the electrolysis water unit; the working fluid inlet of the oxygen ejector module 19 is connected to the oxygen outlet of the electrolysis water unit, the ejector fluid inlet is fed with purified air, and the outlet is connected to the gas storage tank 20 and the cathode side inlet of the fuel cell stack module 15 in sequence; the fuel cell air outlet gas-liquid separator module 17 is connected to the cathode side air outlet of the fuel cell stack module 15, and is used to perform gas-liquid separation on the gas mixture generated on the cathode side of the fuel cell stack module 15. The obtained liquid is water and is stored in the pure water unit, and the obtained gas is discharged from the hydrogen energy storage power generation system;

[0050] The fuel cell is connected to the power grid unit and is used to supply the electrical energy generated by the fuel cell to the power grid;

[0051] The pure water unit is connected to one side electrode of the electrolysis water unit and is used to provide electrolysis water for the electrolysis water unit.

[0052] In the present invention, the anode circulation ejector module 13 and the oxygen ejector module 19 may specifically adopt ejectors. The fluid with a higher pressure is defined as the working fluid, which flows out of the nozzle at a very high speed, entraining the surrounding fluid and undergoing momentum exchange. The fluid with a lower pressure being sucked away is the ejector fluid. In the anode circulation ejector module 13, the working fluid is the hydrogen produced by the electrolysis water unit, and the hydrogen at the anode side outlet of the fuel cell stack module 15 circulates to the anode circulation ejector module 13 as the ejector fluid and is sucked in by the working fluid and re-enters the fuel cell stack module 15 for an electrochemical reaction. In the oxygen ejector module 19, the working fluid is the oxygen produced by the electrolysis water unit, and the ejector fluid is the purified air at normal pressure. The two are mixed and then enter the gas storage tank 20, increasing the oxygen content therein to provide a reaction gas for the cathode of the fuel cell stack module 15. And by adopting the oxygen ejector module 19 in the present invention, the purified air at normal pressure is entrained and mixed and introduced into the gas storage tank, so that the gas storage tank can be kept under pressure and directly introduced into the fuel cell stack, thus avoiding the use of an air compressor, thereby making full use of the oxygen pressure potential energy and improving the overall efficiency of the system; similarly, by adopting the anode circulation ejector module 13, the hydrogen pressure potential energy is fully utilized, and the overall efficiency of the system is improved.

[0053] In some embodiments of the present invention, when the electric energy generated by the electric energy supply unit is greater than the electric energy required by the power grid, the electric energy supply unit supplies the electric energy that cannot be consumed by the power grid to the water electrolysis unit for electrolyzing water to produce hydrogen and oxygen.

[0054] In some embodiments of the present invention, when the electric energy supplied by the electric energy supply unit cannot meet the demand of the power grid, the fuel cell unit is connected to the power grid unit and is used to supply the electric energy generated by the fuel cell unit to the power grid.

[0055] In some embodiments of the present invention, the electric energy supply unit includes a power station and a voltage conversion module; wherein, the voltage conversion module converts the voltage of the electric energy generated by the power station and supplies it to users (such as the power grid or the water electrolysis unit).

[0056] In some embodiments of the present invention, the power station includes at least one of a thermal power station and a renewable energy power station. Preferably, a renewable energy power station is adopted to utilize renewable energy and protect the sustainability of the environment.

[0057] In some embodiments of the present invention, the water electrolysis unit includes an electrolytic cell 3, a hydrogen separation and purification module 5, a hydrogen storage module 10, an oxygen separation and purification module 4, and an oxygen storage module 9; wherein, the electrolytic cell 3 is used to electrolyze water to produce hydrogen and oxygen.

[0058] In some embodiments of the present invention, the hydrogen separation and purification module 5 is connected to the cathode side of the electrolytic cell 3 and is used to separate the gas discharged from the cathode side outlet of the electrolytic cell 3 to obtain hydrogen and water vapor; the separated hydrogen enters the hydrogen storage module 10 for storage; the separated water vapor enters the pure water tank 7 for storage.

[0059] In some embodiments of the present invention, the oxygen separation and purification module 4 is connected to the anode side of the electrolytic cell 3 and is used to separate the gas discharged from the anode side outlet of the electrolytic cell 3 to obtain oxygen and water vapor; the separated oxygen enters the oxygen storage module 9 for storage; the separated water vapor enters the pure water tank 7 for storage.

[0060] In some embodiments of the present invention, the fuel cell stack module 15 is connected to the power grid 16 via the voltage conversion unit 21 and is used to supply the electric energy generated by the fuel cell stack module 15 to the power grid.

[0061] In some embodiments of the present invention, the outlet of the gas storage tank 20 is connected to the cathode side inlet of the fuel cell stack module 15 and is used to supply air or oxygen to the fuel cell stack module 15.

[0062] In some embodiments of the present invention, it is connected to the inlet of the oxygen ejector module 19 and the gas storage tank 20, and is used to supply the oxygen in the oxygen ejector module 19 to the gas storage tank 20 to increase the amount of oxygen in the gas storage tank 20.

[0063] In some embodiments of the present invention, the anode tail gas discharge module 14 includes an inlet and two outlets, namely the tail gas outlet and the hydrogen outlet. The inlet of the anode tail gas discharge module 14 is connected to the anode side outlet of the fuel cell stack module 15, and is used to regularly discharge the gas mixture generated on the anode side of the fuel cell stack module 15 to prevent the enrichment of impurity gases. The hydrogen generated during non-discharge is discharged through the hydrogen outlet and enters the anode circulation ejector module 13 for standby, and the regularly discharged tail gas is discharged from the hydrogen energy storage power generation system.

[0064] In some embodiments of the present invention, a first flow path and a second flow path are formed by the hydrogen storage module in the electrolyzed water unit, the anode circulation ejector module in the fuel cell unit, the anode tail gas discharge module and the anode circulation ejector module on the anode side of the fuel cell stack module; wherein the first flow path is formed by sequentially connecting the hydrogen storage module 10, the anode circulation ejector module 13, and the anode side inlet of the fuel cell stack module 15, and is used to eject the hydrogen prepared by the electrolytic cell 3 to the anode of the fuel cell stack module 15 as a hydrogen raw material for chemical reaction.

[0065] In some embodiments of the present invention, the second flow path is formed by sequentially connecting the anode side of the fuel cell stack module 15, the anode tail gas discharge module 14, and the anode circulation ejector module 13, and is used to recover the unreacted hydrogen discharged from the anode side of the fuel cell stack module 15 to the anode circulation ejector module 13 for ejection to the anode side of the fuel cell stack module 15 for recycling.

[0066] In some embodiments of the present invention, the oxygen storage module 9, the oxygen ejector module 19 are connected to the cathode side inlet of the fuel cell stack module 15, and are used to eject the oxygen generated by the electrolyzed water unit to the cathode side of the fuel cell stack module 15 as an oxygen raw material for reaction.

[0067] In some embodiments of the present invention, the fuel cell unit further includes an oxygen pressure regulating module 22.

[0068] In some embodiments of the present invention, the oxygen storage module 9 and the oxygen ejector module 19 are connected through the oxygen pressure regulating module 22, and are used to regulate the pressure of the oxygen gas flow in the pipeline.

[0069] In some embodiments of the present invention, the fuel cell air outlet gas-liquid separator module 17 is connected to the cathode side outlet of the fuel cell stack module 15, and is used for separating the gas mixture generated on the cathode side of the fuel cell stack module 15 into gas and liquid. The obtained liquid is water and is stored in the pure water tank 7; the obtained gas is discharged from the hydrogen energy storage power generation system.

[0070] In some embodiments of the present invention, the fuel cell unit further includes a back pressure valve 18.

[0071] In some embodiments of the present invention, a back pressure valve 18 is provided between the fuel cell air outlet gas-liquid separator module 17 and the cathode side outlet of the fuel cell stack module 15, and the gas pressure in the pipeline is controlled by the back pressure valve 18.

[0072] In some embodiments of the present invention, the pure water unit includes a pure water tank 7, a pure water pump 6, a water supply module 11 and a pure water production module 12. The pure water unit is used for preparing and collecting the water generated by the fuel cell for electrolysis. Among them, the pure water production module 12 is used for preparing water.

[0073] In some embodiments of the present invention, the pure water unit is connected to the cathode side of the fuel cell unit and is used for collecting the water generated by the fuel cell unit.

[0074] In some embodiments of the present invention, a waste heat recovery unit is further included. The waste heat recovery unit is respectively connected to the water electrolysis unit and the fuel cell unit, and is used for recovering the waste heat generated by the water electrolysis unit and the waste heat generated by the fuel cell unit.

[0075] In some embodiments of the present invention, the waste heat recovery unit includes a water electrolysis heat exchange unit 8 and a fuel cell cooling module 24. Among them, the water electrolysis heat exchange unit 8 is connected to the oxygen separation and purification module 4 and the pure water tank 7, and is used for recovering the waste heat generated by the water electrolysis unit; the fuel cell cooling module 24 is respectively connected to the anode outlet and the cathode outlet of the fuel cell stack module 15, and is used for recovering the waste heat generated by the fuel cell unit.

[0076] According to some embodiments of the second aspect of the present invention, a hydrogen energy storage power generation method is provided, and the power generation method uses any one of the above hydrogen energy storage power generation systems for power generation.

[0077] Example 1

[0078] As Figure 1 shown, in this preferred embodiment, the hydrogen energy storage power generation system includes an electric energy supply unit, a water electrolysis unit, a fuel cell unit, a pure water unit and a waste heat recovery unit; among them,

[0079] The electric energy supply unit includes a renewable energy power generation station 1 and a voltage conversion module 2;

[0080] The electrolyzed water unit includes an electrolytic cell 3, a hydrogen separation and purification module 5, a hydrogen storage module 10, an oxygen separation and purification module 4, and an oxygen storage module 9; this electrolyzed water unit is used to convert the excess power generated by the renewable energy power station 1 that cannot be absorbed by the power grid into hydrogen for energy storage;

[0081] The fuel cell unit includes a fuel cell stack module 15, an anode circulation ejector module 13, an anode tail gas discharge module 14, an oxygen pressure regulation module 22, an oxygen ejector module 19, a gas storage tank 20, a back pressure valve 18, a fuel cell air outlet gas-liquid separator module 17, a voltage conversion unit 21, and a power grid 16; this fuel cell unit is used to convert hydrogen energy into electrical energy and feed it into the power grid when the power grid is short of electricity;

[0082] The pure water unit includes a pure water tank 7, a pure water pump 6, a water supply module 11, and a pure water production module 12. This pure water unit is used to prepare and collect the water generated by the fuel cell for electrolysis;

[0083] The waste heat recovery unit includes an electrolyzed water heat exchange unit 8 and a fuel cell cooling module 24; this waste heat recovery unit is used to recover the waste heat of electrolyzed water and the waste heat of the fuel cell. Specifically,

[0084] The renewable energy power station 1 is connected to the power grid unit and is used to supply electrical energy to the power grid; when the electrical energy generated by the electrical energy supply unit is greater than the electrical energy required by the power grid, the renewable energy power station 1 is connected to the electrolyzed water unit through a voltage conversion module 2 and is used to supply the electrical energy that cannot be absorbed by the power grid generated by the electrical energy supply unit to the electrolyzed water unit for electrolyzing water to produce hydrogen and oxygen;

[0085] The pure water tank 7 in the pure water unit is connected to one side of the electrodes of the electrolytic cell 3 in the electrolyzed water unit. The pure water produced by the pure water production module 12 is stored in the pure water tank 7 and is transported to the electrolytic cell 3 by the pure water pump 6 for electrolyzing water to produce hydrogen and oxygen.

[0086] In the electrolyzed water unit, the cathode side of the electrolytic cell 3 is connected to the hydrogen separation and purification module 5. After the electrolytic cell 3 electrolyzes water, the gas mixture generated on the cathode side is separated by the hydrogen separation and purification module 5 to obtain hydrogen and water vapor. The separated hydrogen enters the hydrogen storage module 10 for storage, and the separated water vapor enters the pure water tank 7 for storage; the anode side of the electrolytic cell 3 is connected to the oxygen separation and purification module 4. The gas mixture generated on the anode side of the electrolytic cell 3 is separated by the oxygen separation and purification module 4 to obtain oxygen and water vapor. The separated oxygen enters the oxygen storage module 9 (such as an oxygen storage tank) for storage, and the separated water vapor enters the pure water tank 7 for storage.

[0087] The electrolyzed water unit is connected to the fuel cell and is used to supply the hydrogen and oxygen produced by the electrolyzed water unit to the fuel cell for reaction to convert chemical energy into electrical energy; specifically,

[0088] The hydrogen storage module 10 (such as a hydrogen storage tank) in the electrolyzed water unit is sequentially connected to the anode circulation ejector module 13 (such as an ejector), the anode side of the fuel cell stack module 15, the anode tail gas discharge module 14 (such as a tail gas discharge valve), and the anode circulation ejector module 13 in the fuel cell unit to form a first flow path and a second flow path; wherein the first flow path is formed by sequentially connecting the hydrogen storage module 10, the anode circulation ejector module 13, and the anode side inlet of the fuel cell stack module 15. The first flow path injects the hydrogen gas prepared by the electrolyzed water unit into the anode of the fuel cell stack module 15 in the fuel cell unit to provide hydrogen raw materials; the second flow path is formed by sequentially connecting the anode side gas outlet of the fuel cell stack module 15, the anode tail gas discharge module 14, and the anode circulation ejector module 13, and is used to recycle the unreacted hydrogen gas separated from the gas mixture discharged from the anode side of the fuel cell stack module 15 to the anode circulation ejector module 13 for injection into the anode side of the fuel cell stack module 15 for reuse.

[0089] The oxygen storage module 9 in the electrolyzed water unit is sequentially connected to the oxygen ejector module 19, the gas storage tank 20, and the cathode side inlet of the fuel cell stack module 15 in the fuel cell unit, and injects the oxygen generated by the electrolyzed water unit into the gas storage tank 20, and then supplies oxygen raw materials to the cathode side of the fuel cell stack module 15 through the gas storage tank 20.

[0090] The power generation performance of the fuel cell is related to the oxygen content in the cathode reaction gas. The higher the oxygen content, the higher the power generation efficiency of the fuel cell. In this embodiment, the oxygen generated by the electrolyzed water unit is introduced into the gas storage tank 20 to increase the oxygen content of the gas in the gas storage tank. Therefore, this embodiment comprehensively utilizes the oxygen generated by electrolyzed water, can increase the oxygen content of the cathode reaction gas, and thus improve the efficiency of the hydrogen energy storage power generation system. In this embodiment, the power generation efficiency of the fuel cell can reach 50 - 65% (for example, 52%, 55%, 58%, 60% or 63%).

[0091] When the electric energy supplied by the renewable energy power station cannot meet the demand of the power grid, the fuel cell unit is connected to the power grid unit through the voltage conversion unit 21, and the electric energy generated by the fuel cell unit is supplied to the power grid. The gas mixture generated by the fuel cell unit can be processed by the following method. Specifically,

[0092] The fuel cell stack module 15 generates electricity using hydrogen and air as raw materials. The gas mixture generated on the anode side of the fuel cell stack module 15 passes through the anode tail gas discharge module 14 (including an inlet and two outlets, namely the tail gas outlet and the hydrogen outlet), which is used to regularly discharge the gas mixture generated on the anode side of the fuel cell stack module 15 to prevent the enrichment of impurity gases. The hydrogen generated when not discharged is discharged through the hydrogen outlet and enters the anode circulation ejector module 13 for standby, and the regularly discharged tail gas is discharged from the hydrogen energy storage power generation system.

[0093] The air outlet on the cathode side of the fuel cell stack module 15 of the fuel cell unit is connected to the pure water tank 7 of the pure water unit through the fuel cell air outlet gas-liquid separator module 17 (such as a gas-liquid separator). The gas mixture discharged from the air outlet on the cathode side of the fuel cell stack module 15 is subjected to gas-liquid separation by the fuel cell air outlet gas-liquid separator module 17. The resulting liquid is water and is stored in the pure water tank 7; the resulting gas is discharged from the hydrogen energy storage power generation system. Therefore, the water generated by the fuel cell unit can be input into the electrolytic water unit through the pure water tank to electrolyze water to produce hydrogen and oxygen, thereby realizing the comprehensive utilization of the water produced by the fuel cell unit. As Figure 1 The operation method of the hydrogen energy storage power generation system shown is as follows.

[0094] (1) When the power grid cannot absorb the electric energy generated by the renewable energy power generation station 1, the electrolytic water unit is started, and the renewable energy power generation station 1 converts the voltage into the direct current required by the electrolytic cell 3 through the voltage conversion module 2;

[0095] The pure water tank 7 pumps pure water into one side of the electrolytic cell 3 through the pure water pump 6, and the electrolytic cell generates an electrolytic reaction to produce a hydrogen gas stream and an oxygen gas stream; among them,

[0096] The oxygen gas stream passes through the oxygen separation and purification module 4 to separate water and oxygen. The oxygen enters the oxygen storage module 9 through the pipeline, and the water enters the electrolytic water heat exchange unit 8 through the pipeline, and returns to the pure water tank 7 for recycling after cooling;

[0097] The hydrogen gas stream passes through the hydrogen separation and purification module 5 to separate hydrogen and water, and the hydrogen enters the hydrogen storage module 10 through the pipeline.

[0098] Among them, the electrolytic cell 3 can be an alkaline electrolytic cell, a PEM electrolytic cell, or an AEM electrolytic cell, preferably a PEM electrolytic cell. The hydrogen storage pressure is 0.8 - 30 MPa (for example, 1 MPa, 10 MPa, 20 MPa, or 25 MPa), and the oxygen storage pressure is 0.8 - 30 MPa (for example, 1 MPa, 10 MPa, 20 MPa, or 25 MPa).

[0099] (2) When the electric energy generated by the renewable energy power station cannot meet the grid load, the fuel cell unit starts. The hydrogen in the hydrogen storage module 10 enters the anode circulation ejector module 13 after primary pressure reduction. High-pressure hydrogen (the same as or slightly lower than the hydrogen storage pressure in the hydrogen storage module 10, 0.8 - 30 MPa) serves as the working fluid, and the fuel cell anode outlet gas serves as the ejector fluid. After mixing in the anode circulation ejector module 13, it enters the anode inlet of the fuel cell stack module 15. The anode outlet gas of the fuel cell stack module 15 is regularly discharged through the anode tail gas discharge module 14 to remove the enriched impurities. The ejector ratio of the anode circulation ejector module (the ratio of the mass flow rate of the ejector fluid to the mass flow rate of the working fluid) is 0.5 - 3 (for example, 1, 2, or 2.5).

[0100] The oxygen in the oxygen storage module 9 enters the cathode oxygen ejector module 19 after passing through the oxygen pressure regulating module 22 (i.e., pressure reducing valve). High-pressure oxygen (the same as or slightly lower than the oxygen storage pressure in the oxygen storage module 9, 0.8 - 30 MPa) serves as the working fluid. After mixing with the filtered air, it enters the cathode gas inlet of the fuel cell stack module 15. The reacted cathode outlet gas enters the fuel cell air outlet gas-liquid separator module 17 (i.e., gas-water separator) through the back pressure valve 18. The generated water enters the pure water tank 7, and the gas is discharged as tail gas. The ejector ratio of this oxygen ejector module is 0.3 - 5 (for example, 1, 2, 3, 4, or 4.5). The oxygen concentration sensor ( Figure 1 not marked in the figure) is used to measure the oxygen concentration at the cathode gas inlet, and adjusts the gas pressure and flow rate at the oxygen tank outlet through the feedback signal. The oxygen concentration range is 25 - 70% (for example, 30%, 40%, 50%, 60%, or 75%). The fuel cell cooling water is recycled after passing through the heat exchange module 24. The electricity generated by the fuel cell is supplied to the power grid 16 through the voltage conversion unit 21.

[0101] The waste heat recovery unit recovers the waste heat generated by the electrolyzed water heat exchange unit 8 and the fuel cell coolant heat dissipation module 16, and supplies it to the pure water production module 12 to produce pure water. The pure water production equipment preferably uses a vacuum flash evaporator.

[0102] It should be noted that, in this document, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0103] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A hydrogen energy storage power generation system, wherein, The hydrogen energy storage power generation system includes a power supply unit, a power grid unit, a water electrolysis unit, a fuel cell unit, and a pure water unit; wherein, The power supply unit is connected to the power grid unit and is used to supply electric energy to the power grid; The power supply unit is connected to the water electrolysis unit and is used to supply the electric energy generated by the power supply unit to the water electrolysis unit for electrolyzing water to produce hydrogen and oxygen; The water electrolysis unit is connected to the fuel cell and is used to supply the hydrogen and oxygen produced by the water electrolysis unit to the fuel cell for an electrochemical reaction to convert chemical energy into electric energy; The fuel cell unit includes a fuel cell stack module, an anode circulation ejector module, an oxygen ejector module, a fuel cell air outlet gas-liquid separator module, and a gas storage tank; wherein, the fuel cell stack module is used to convert the chemical energy generated by the electrochemical reaction of hydrogen and oxygen into electric energy; the anode side outlet of the fuel cell stack module, the ejector fluid inlet of the anode circulation ejector module, the outlet of the anode circulation ejector module, and the anode side inlet of the fuel cell stack module are connected in sequence; the working fluid inlet of the anode circulation ejector module is connected to the hydrogen outlet of the water electrolysis unit; the working fluid inlet of the oxygen ejector module is connected to the oxygen outlet of the water electrolysis unit, the ejector fluid inlet is introduced with purified air, and the outlet is connected to the gas storage tank and the cathode side inlet of the fuel cell stack module in sequence; the fuel cell air outlet gas-liquid separator module is connected to the cathode side air outlet of the fuel cell stack module and is used to perform gas-liquid separation on the gas mixture generated on the cathode side of the fuel cell stack module. The obtained liquid is water and is stored in the pure water unit, and the obtained gas is discharged from the hydrogen energy storage power generation system; The fuel cell is connected to the power grid unit and is used to supply the electric energy generated by the fuel cell to the power grid; The pure water unit is connected to one side electrode of the water electrolysis unit and is used to provide electrolytic water for the water electrolysis unit.

2. The hydrogen energy storage power generation system according to claim 1, wherein, When the electric energy generated by the power supply unit is greater than the electric energy required by the power grid, the electric energy that cannot be consumed by the power grid is supplied to the water electrolysis unit for electrolysis to produce hydrogen and oxygen.

3. The hydrogen energy storage power generation system according to claim 1, wherein, When the electric energy supplied by the power supply unit cannot meet the demand of the power grid, the fuel cell is connected to the power grid unit and is used to supply the electric energy generated by the fuel cell to the power grid.

4. The hydrogen energy storage power generation system according to claim 1, wherein, The power supply unit includes a power station and a voltage conversion module; wherein, the voltage conversion module converts the electric energy generated by the power station and supplies it to users.

5. The hydrogen energy storage power generation system according to claim 4, wherein, The power station includes a renewable energy power station.

6. The hydrogen energy storage power generation system according to claim 1, wherein, The water electrolysis unit includes an electrolytic cell, a hydrogen separation and purification module, a hydrogen storage module, an oxygen separation and purification module, and an oxygen storage module; wherein, the electrolytic cell is used to electrolyze water to produce hydrogen and oxygen.

7. The hydrogen energy storage power generation system according to claim 6, wherein, In the water electrolysis unit, the hydrogen separation and purification module is connected to the cathode side of the electrolytic cell and is used to separate the gas discharged from the cathode side outlet of the electrolytic cell to obtain hydrogen and water vapor; the separated hydrogen enters the hydrogen storage module for storage, and the separated water vapor enters the pure water tank for storage.

8. The hydrogen energy storage power generation system according to claim 6, wherein, In the electrolyzed water unit, the oxygen separation and purification module is connected to the anode side of the electrolytic cell, and is used for separating the gas discharged from the anode side outlet of the electrolytic cell into oxygen and water vapor; the separated oxygen enters the oxygen storage module for storage, and the separated water vapor enters the pure water tank for storage.

9. The hydrogen energy storage power generation system according to claim 1, wherein The fuel cell stack module is connected to the power grid through a voltage conversion unit, and is used for supplying the electric energy generated by the fuel cell stack module to the power grid.

10. The hydrogen energy storage power generation system according to claim 6, wherein, In the fuel cell unit, an anode tail gas discharge module is further provided on the connecting pipeline between the anode side outlet of the fuel cell stack module and the injection fluid inlet of the anode circulation ejector module; The anode tail gas discharge module includes an inlet and two outlets. The two outlets are respectively a tail gas discharge outlet and a hydrogen outlet. The inlet of the anode tail gas discharge module is connected to the anode side outlet of the fuel cell stack module, and the hydrogen outlet is connected to the injection fluid inlet of the anode circulation ejector module.

11. The hydrogen energy storage power generation system according to claim 10, wherein, A first flow path and a second flow path are formed by the hydrogen storage module in the electrolyzed water unit, the anode circulation ejector module in the fuel cell unit, the anode side of the fuel cell stack module, the anode circulation ejector module and the anode tail gas discharge module and the anode circulation ejector module; wherein the first flow path is formed by connecting the hydrogen storage module, the anode circulation ejector module, and the anode side inlet of the fuel cell stack module in sequence, and is used for injecting the hydrogen prepared by the electrolytic cell to the anode of the fuel cell stack module as a hydrogen raw material for an electrochemical reaction; The second flow path is formed by connecting the anode side of the fuel cell stack module, the anode tail gas discharge module and the anode circulation ejector module in sequence, and is used for recovering the unreacted hydrogen discharged from the anode side of the fuel cell stack module to the anode circulation ejector module for injection to the anode side of the fuel cell stack module again for reuse.

12. The hydrogen energy storage power generation system according to claim 6, wherein, The oxygen storage module in the electrolyzed water unit is connected to the oxygen injection module in the fuel cell unit and the cathode side inlet of the fuel cell stack module, and is used for injecting the oxygen generated by the electrolyzed water unit to the cathode side of the fuel cell stack module for reaction.

13. The hydrogen energy storage power generation system according to claim 12, wherein, The fuel cell unit further includes an oxygen pressure regulating module; the oxygen storage module in the electrolyzed water unit and the oxygen injection module in the fuel cell unit are connected via the oxygen pressure regulating module, and are used for regulating the pressure of the oxygen gas flow in the pipeline.

14. The hydrogen energy storage power generation system according to claim 1, wherein, The fuel cell unit further includes a back pressure valve; The back pressure valve is provided between the fuel cell air outlet gas-liquid separator module and the cathode side outlet of the fuel cell stack module, and the cathode side pressure of the fuel cell stack is controlled by the back pressure valve.

15. The hydrogen energy storage power generation system according to claim 1, wherein, The pure water unit includes a pure water tank, a pure water pump, a water supply module and a pure water production module, and the pure water unit is used for preparing and collecting the water generated by the fuel cell for electrolysis; The pure water unit is connected to the cathode side of the fuel cell unit, and is used for collecting the water generated by the fuel cell unit.

16. The hydrogen energy storage power generation system according to claim 15, wherein, The hydrogen energy storage power generation system further includes a waste heat recovery unit, which is respectively connected to the electrolyzed water unit and the fuel cell unit for recovering the waste heat generated by the electrolyzed water unit and the waste heat generated by the fuel cell unit.

17. The hydrogen energy storage power generation system according to claim 16, wherein, The waste heat recovery unit includes an electrolyzed water heat exchange unit and a fuel cell cooling module, wherein, The electrolyzed water heat exchange unit is connected to the oxygen separation and purification module and the pure water tank for recovering the waste heat generated by the electrolyzed water unit; the fuel cell cooling module is respectively connected to the anode outlet and the cathode outlet of the fuel cell stack module for recovering the waste heat generated by the fuel cell unit.

18. A hydrogen energy storage power generation method, wherein, The method generates electricity according to the hydrogen energy storage power generation system according to any one of claims 1-17.

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