Improved energy storage electricity and heat combined supply system

Abstract

The invention relates to an improved energy storage electricity and heat combined supply system which comprises an energy management system, a hydrogen production system, a heat storage system and a hydrogen storage system which are matched with one another, and the energy management system comprises a main station energy management system, an electrolytic cell array management system and a salt cavity pressure management system. The electrolytic cell array management system is connected with the hydrogen production system through a temperature sensor and a state monitoring sensor, the salt cavern pressure management system is connected with the hydrogen storage system through a salt cavern inlet and outlet pressure sensor, and the heat storage system is connected with the hydrogen production system and the hydrogen storage system. The energy management system is adopted to monitor the hydrogen control system in real time, green hydrogen is prepared by utilizing renewable energy source surplus power and stored in the hydrogen storage system, meanwhile, the heat storage system is coupled to recover and store system byproduct waste heat in the operation period, the system energy comprehensive utilization efficiency is improved, large-scale and long-time-scale storage of energy after electric thermal decoupling is achieved, and the energy utilization rate is increased. And the electricity abandoning rate of renewable energy sources and the overall carbon emission level of the system are reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated energy systems, and in particular relates to an improved energy storage combined heat and electricity supply system. Background Art

[0002] As an excellent large-scale gas storage method, salt cavern gas storage can be fully combined with compressed air energy storage systems. The thickness of underground salt caverns formed by mining salt rock layers varies from a few meters to tens of meters to hundreds of meters, and the general burial depth is between 800 and 2000m. In some areas, it can reach five or six kilometers. These salt caverns are not only large in size, but also can remain stable for a long time due to the low permeability of salt rock, stable mechanical properties, and self-healing of damage. my country is rich in salt cavern resources. At present, the total volume of underground salt caverns has reached more than 250 million cubic meters. Using them for large-scale hydrogen storage is not only low-cost, flexible in storage and use, and saves land resources, but also has a reserve scale of up to gigawatts. Therefore, salt cavern hydrogen storage is currently the most promising choice for large-scale hydrogen storage, and may become an important link in the hydrogen energy industry chain.

[0003] Conventional integrated energy systems have limited effects in reducing the use of fossil fuels and carbon emissions due to problems such as single energy conversion forms and low efficiency. The efficiency of the water electrolysis process to produce hydrogen is only 60% to 70%, and the efficiency of the fuel cell hydrogen combustion process to generate electricity is only 40% to 55%. Most of the remaining energy is lost in the form of heat. Therefore, it is necessary to explore the heating capacity of renewable energy production and hydrogen use, which will play a positive role in optimizing the electric-thermal coupling and energy efficiency of the integrated energy system. Summary of the invention

[0004] The purpose of the present invention is to provide an improved energy storage combined heat and power generation system for absorbing a high proportion of renewable energy, improving the operating efficiency of the existing comprehensive energy system, and reducing the carbon emission level of the power system.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an improved energy storage combined heat and electricity supply system, including an energy management system, a hydrogen production system, a heat storage system and a hydrogen storage and utilization system that cooperate with each other;

[0006] The energy management system includes a main station energy management system, an electrolyzer array management system, and a salt cavity pressure management system. The electrolyzer array management system is connected to the hydrogen production system via a temperature sensor and a status monitoring sensor. The salt cavity pressure management system is connected to the hydrogen storage system via salt cavern inlet and outlet pressure sensors. The heat storage system is connected to the hydrogen production system and the hydrogen storage system.

[0007] The hydrogen production system comprises a renewable energy power supply device for supplying energy to an electrolyzer array, and an alkaline electrolyzer array for producing hydrogen by electrolysis;

[0008] The heat storage system comprises a first heat exchanger, a second heat exchanger, a phase change heat storage device and a heat load supply terminal, the electrolyzer array is connected to the first heat exchanger, the inlet of the phase change heat storage device is connected to the first heat exchanger, the compressor and the second heat exchanger, and the outlet is connected to the heat load supply terminal and the turbine;

[0009] The hydrogen storage and distribution system comprises a hydrogen / water separator, a compressor, a salt cavern, a turbine, a hydrogen fuel cell group and an electric load supply terminal, the first heat exchanger is connected to the air inlet of the hydrogen / water separator, the hydrogen / water separator is connected to the compressor, the compressor is connected to the salt cavern, the salt cavern is connected to the turbine, the turbine is connected to the hydrogen fuel cell group, and the hydrogen fuel cell group is connected to the electric load supply terminal via an inverter and an AC bus;

[0010] Preferably, the renewable energy power supply device includes wind power, photovoltaic power and underground salt cavity biomass energy, which are connected to the electrolytic cell array through an AC bus and a rectifier;

[0011] Preferably, the master station energy management system is used to monitor the salt cavern cavity pressure and the rotation status of the electrolytic cell array in real time, and the master station energy management system uses the communication interface RS485 to communicate and interact with the electrolytic cell array management system and the salt cavern pressure management system respectively.

[0012] Preferably, the operating power of any electrolytic cell in the electrolytic cell array is not less than 20% of the rated power, and the short-term overload power of the electrolytic cell does not exceed 125% of the rated power;

[0013] Preferably, the ratio of the electrolyzer array configuration capacity to the renewable energy power supply device configuration capacity is 4:5;

[0014] Preferably, the phase change heat storage device adopts a shell and tube heat storage device, wherein the inside of the shell and tube heat storage device is a heat transfer fluid and the outside of the tube is a phase change heat storage material, and the phase change heat storage material adopts a graphite foam / inorganic salt high temperature composite phase change material;

[0015] Preferably, the hydrogen storage and distribution system further comprises a water reservoir, the hydrogen fuel cell group is respectively connected to the second heat exchanger and the water reservoir, and the water reservoir is also respectively connected to the electrolyzer array and the hydrogen / water separator drain valve;

[0016] Preferably, the salt cavern hydrogen storage reservoir has a cavity volume of not less than 5*10 5 m 3The salt cavern salt rock burial depth is not less than 1100m and not more than 1500m, the salt cavern cavity pressure is not less than 3MPa and not more than 15MPa, and the salt cavern uses a working pressure of not less than 7.58MPa and not more than 14.8MPa during the hydrogen injection stage;

[0017] Due to the above technical solution, the present invention has the following advantages compared with the prior art:

[0018] The present invention adopts an energy management system to monitor the hydrogen production system in real time, utilizes the surplus electricity produced by renewable energy to produce green hydrogen and stores it in the hydrogen storage system. At the same time, it couples the heat storage system to recover and store the waste heat produced during the operation of the system, thereby improving the comprehensive energy utilization efficiency of the system, realizing large-scale and long-term storage of energy after electric and thermal decoupling, and reducing the renewable energy abandonment rate and the overall carbon emission level of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention;

[0020] Among them: 10. Renewable energy power generation device; 11. Alkaline electrolyzer array; 12. Fuel cell group; 13. Water reservoir; 14. Power supply terminal; 20. First heat exchanger; 21. Second heat exchanger; 22. Phase change heat storage device; 23. Thermal power supply terminal; 30. Hydrogen / water separator; 31. Compressor; 32. Salt cavern; 33. Turbine; 40. Energy management system; 41. Electrolyzer array management system; 42. Salt cavity pressure management system. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] See also Figure 1 An improved energy storage combined heat and power system includes an energy management system, a hydrogen production system, a heat storage system, and a hydrogen storage system that cooperate with each other. It can absorb a high proportion of renewable energy, improve the operating efficiency of the existing comprehensive energy system, and reduce the carbon emission level of the power system.

[0023] The energy management system includes a main station energy management system 40, an electrolyzer array management system 41, and a salt chamber pressure management system 42. The hydrogen production system includes a renewable energy power supply device 11 for supplying energy for water electrolysis and an electrolyzer array 10 for producing hydrogen by electrolysis. The renewable energy power supply device integrates wind power, photovoltaic power, and underground salt chamber biomass energy, and connects the electrolyzer array to produce hydrogen after being stepped down and rectified by the AC bus. The electrolyzer is an alkaline electrolyzer with high efficiency and wide commercial application range. In order to ensure that the system does not have extreme operating conditions, the total configuration capacity of the electrolyzer array and the configuration capacity of the renewable energy power supply device are in a ratio of 4:5.

[0024] The electrolyzer array 10 adopts a rotation optimization control strategy under the real-time monitoring of the electrolyzer array management system 41: when there is surplus power from renewable energy, the electric power to be absorbed is first distributed to each electrolysis device in the electrolyzer array 10. When the first electrolyzer is at rated power, the remaining power is distributed to the second electrolyzer, and the electrolyzer array management system 41 should ensure that the operating power of each electrolyzer is not less than 20% of the rated rate, otherwise it will be shut down until the renewable energy power is fully absorbed; if the electrolyzer array is operating at rated power and there is still surplus power, the remaining power will continue to be distributed step by step to each electrolyzer in the array for short-term overload operation, and the short-term overload power shall not exceed 125% of its own rated power, and the short-term overload operation time shall not exceed 2.5 minutes. When the electrolyzer array management system 41 detects that the working time of a certain electrolyzer has reached the rotation cycle of 5 minutes, the electrolyzer array management system 41 will shut it down, and the power borne by this electrolyzer will continue to be distributed step by step according to the above strategy to ensure that the electrolyzer array 10 is always in an efficient rotation state. When executing the above-mentioned rotation optimization control strategy, the electrolytic cell array management system 41 always exchanges real-time information with the main station energy management system 40 through the communication interface RS485. If an emergency or special situation occurs, the main station management system 41 can issue instructions or take necessary measures in time to ensure system stability.

[0025] The heat storage system includes a first heat exchanger 20, a second heat exchanger 21, a phase change heat storage device 22 and a heat load supply terminal 23. The first heat exchanger 20 is connected to the electrolytic cell array 11. The operating temperature of the electrolytic cell array 11 is controlled between 50°C and 90°C by using a circulating thermal water return system, and the collected heat is sent to the shell and tube heat storage device 22. The shell and tube heat storage device has a heat transfer fluid in the tube that conducts the heat to the outside of the tube. The graphite foam / inorganic salt high-temperature composite phase change material outside the tube absorbs heat by using the reverse temperature difference, changing from solid to liquid to store heat. The outlet of the phase change heat storage device 22 is connected to the heat load supply terminal 23, and heat energy is supplied as needed.

[0026] The hydrogen storage system includes a hydrogen / water separator 30, a compressor 31, a salt cavern 32, a turbine 33, a hydrogen fuel cell stack 12, a water reservoir 13 and an electric load supply terminal 14. The salt cavern 32 is a hydrogen storage tank with a cavity volume of not less than 5*10 5 m 3 The buried depth of salt rock in salt cavern 32 is not less than 1100m and not more than 1500m. Salt cavern 32 is connected to salt cavern pressure management system 42 through salt cavern inlet and outlet pressure sensors. Salt cavern pressure management system 42 ensures that the internal pressure of salt cavern is not less than 3MPa and not more than 15MPa. When the pressure of salt cavern is too low, salt cavern 32 only stores hydrogen but does not release hydrogen; when the pressure of salt cavern is too high, salt cavern 32 only releases hydrogen but does not store hydrogen. When there is surplus power from renewable energy and the salt chamber pressure meets the requirements, the salt chamber pressure management system 42 and the main station energy management system 40 simultaneously issue a hydrogen storage instruction, and the electrolyzer array management system 41 controls the electrolyzer array 11 to start hydrogen production. After the produced hydrogen enters the hydrogen / water separator 30 through the first heat exchanger 20, the hydrogen / water separator 30 separates the hydrogen from the water phase, and the water is connected to the reservoir 13 through the outlet drain valve. The reservoir 13 is connected to the electrolyzer array 11, and the former provides the latter with stable raw materials for electrolyzing water to produce hydrogen; the outlet of the hydrogen / water separator 30 is connected to the compressor 31, and after the hydrogen is dehumidified by the dryer, it is sent to the compressor through the pressure stabilizing valve and the pressure regulating valve. The two-stage compression turbine is compressed to a high-pressure state, and the pressure state is not less than 7.58MPa and not more than 14.8MPa. The compressor 31 is connected to the salt cavern 32, and the high-pressure hydrogen is sent to the salt cavern for storage.

[0027] When there is an energy gap in the system and the salt cavern pressure meets the requirements, the salt cavern pressure management system 42 and the main station energy management system 40 simultaneously issue a hydrogen release instruction. The salt cavern pressure management system 42 should ensure that the hydrogen release pressure at the outlet of the salt cavern 32 is not less than 7.58MPa and not more than 14.8MPa. The salt cavern 32 is connected to the turbine 33. The high-pressure hydrogen released from the salt cavern 32 passes through the phase change heat storage device 22. The graphite foam / inorganic salt high-temperature composite phase change material in the phase change heat storage device 22 uses the forward temperature difference to change from liquid to solid to release heat to heat the high-pressure hydrogen, maintain its pressure and temperature, and then expand through the two-stage expansion turbine of the turbine 33 to do work. At this time, a small part of the electricity is obtained by hydrogen driving the turbine 33 to expand and generate electricity, and most of the electricity is obtained by the turbine 33 sending hydrogen into the internal combustion chamber of the hydrogen fuel cell group 12 to burn hydrogen and generate electricity. The water vapor produced by the combustion of the hydrogen fuel cell stack 12 is first sent to the phase change heat storage device 22 for storage through the second heat exchanger 21 circulating thermal water return system, and then recovered to the water reservoir 13 through the water pump. The electric energy generated by the hydrogen fuel cell stack 12 is sent to the electric load supply terminal 14 through the inverter and the AC bus to realize the electric energy return.

[0028] During the entire life cycle of the present invention, the adjustment and monitoring of the operating conditions of each device are carried out in real time based on the information communication network and 5G transmission base station.

[0029] The present invention utilizes an energy management system to monitor the hydrogen production system and the hydrogen storage system in real time, utilizes surplus electricity produced by renewable energy to produce green hydrogen and stores it in the underground salt caverns of the hydrogen storage system, thereby realizing large-scale and long-term energy storage and reducing the rate of renewable energy abandonment. The present invention utilizes a heat storage system to recover and store waste heat generated during the electrolysis process, the compressor compression of hydrogen, and the combustion process of the fuel cell group, and supplies the system's thermal load terminal as needed, thereby improving the system's comprehensive energy utilization efficiency and realizing electric-thermal decoupling storage. During the use of the present invention, the energy conversion carrier is always green hydrogen, so while performing electric-thermal load co-supply, the overall carbon emission level of the system is greatly reduced.

Claims

1. An improved energy storage combined heat and power generation system, characterized in that: It includes energy management system, hydrogen production system, heat storage system and hydrogen storage and utilization system that cooperate with each other; The energy management system includes a main station energy management system, an electrolyzer array management system, and a salt cavity pressure management system. The electrolyzer array management system is connected to the hydrogen production system via a temperature sensor and a status monitoring sensor. The salt cavity pressure management system is connected to the hydrogen storage system via salt cavern inlet and outlet pressure sensors. The heat storage system is connected to the hydrogen production system and the hydrogen storage system.

2. The improved energy storage combined heat and power generation system according to claim 1, characterized in that: The hydrogen production system comprises a renewable energy power supply device for supplying energy to an electrolyzer array and an alkaline electrolyzer array for producing hydrogen by electrolysis.

3. The improved energy storage combined heat and power generation system according to claim 1, characterized in that: The heat storage system includes a first heat exchanger, a second heat exchanger, a phase change heat storage device and a heat load supply terminal. The electrolytic cell array is connected to the first heat exchanger, the inlet of the phase change heat storage device is connected to the first heat exchanger, the compressor and the second heat exchanger, and the outlet is connected to the heat load supply terminal and the turbine.

4. The improved energy storage combined heat and power generation system according to claim 1, characterized in that: The hydrogen storage and distribution system includes a hydrogen / water separator, a compressor, a salt cavern, a turbine, a hydrogen fuel cell group and an electric load supply terminal. The first heat exchanger is connected to the air inlet of the hydrogen / water separator, the hydrogen / water separator is connected to the compressor, the compressor is connected to the salt cavern, the salt cavern is connected to the turbine, the turbine is connected to the hydrogen fuel cell group, and the hydrogen fuel cell group is connected to the electric load supply terminal via an inverter and an AC bus.

5. The improved energy storage combined heat and power generation system according to claim 2, characterized in that: The renewable energy power supply device includes wind power, photovoltaic power and underground salt cavity biomass energy, which are connected to the electrolytic cell array through an AC bus and a rectifier.

6. The improved energy storage combined heat and power generation system according to claim 1, characterized in that: The master station energy management system is used to monitor the salt cavern cavity pressure and the rotation status of the electrolytic cell array in real time. The master station energy management system uses the communication interface RS485 to communicate and interact with the electrolytic cell array management system and the salt cavern pressure management system respectively.

7. The improved energy storage combined heat and power generation system according to claim 2, characterized in that: The operating power of any electrolytic cell in the electrolytic cell array is not less than 20% of the rated power, and the short-term overload power of the electrolytic cell does not exceed 125% of the rated power.

8. The improved energy storage combined heat and power generation system according to claim 2, characterized in that: The ratio of the electrolyzer array configuration capacity to the renewable energy power supply device configuration capacity is 4:

5.

9. The improved energy storage combined heat and power generation system according to claim 3, characterized in that: The phase change heat storage device adopts a shell and tube heat storage device, wherein the shell and tube heat storage device has a heat transfer fluid inside the tube and a phase change heat storage material outside the tube, and the phase change heat storage material adopts a graphite foam / inorganic salt high-temperature composite phase change material.

10. The improved energy storage combined heat and power generation system according to claim 4, characterized in that: The hydrogen storage system also includes a water reservoir. The hydrogen fuel cell group is connected to the second heat exchanger and the water reservoir respectively. The water reservoir is also connected to an electrolyzer array and a hydrogen / water separator drain valve respectively.

11. The improved energy storage combined heat and power generation system according to claim 4, characterized in that: The salt cavern hydrogen storage reservoir has a cavity volume of not less than 5*10 5 m 3 The salt rock burial depth of the salt cavern is not less than 1100m and not more than 1500m; the cavity pressure of the salt cavern is not less than 3MPa and not more than 15MPa; the working pressure of the salt cavern during the hydrogen injection stage is not less than 7.58MPa and not more than 14.8MPa.

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