Deep peak regulation system for fuel cell energy storage coupling coal-fired unit

Abstract

The utility model belongs to the technical field of energy deep peak regulation, and particularly relates to a deep peak regulation system for a fuel cell energy storage coupling coal-fired unit. The system comprises a new energy generator set, a coal-fired generator set, a fuel cell energy storage device and a control system, the fuel cell energy storage device comprises a molten carbonate fuel cell, the fuel cell comprises a cathode side and an anode side, the cathode side is supplied with gas after desulfurized coal-fired boiler waste gas and compressed fresh air are mixed, and the anode side is supplied with gas after the desulfurized coal-fired boiler waste gas is mixed with compressed fresh air. And the anode side is supplied by hydrogen-rich synthesis gas output by the first exhaust end of the external reformer. After a controller in the control system collects data through various data collection sensors, the output power of the molten carbonate fuel cell is controlled, and it is ensured that the controller controls a fuel cell energy storage device to participate in deep peak regulation of a coal-fired unit in the peak of electricity utilization; and in a low ebb of electricity consumption, the controller controls the surplus electric energy output by the new energy generator set to be used for absorbing the electrolyzed water to produce hydrogen.

Description

Technical Field

[0001] This utility model belongs to the field of deep peak shaving technology for coal-fired power units, specifically relating to a deep peak shaving system for coal-fired power units coupled with fuel cell energy storage. Background Technology

[0002] Electricity supply plays a vital role in the global energy demand structure. For a long time, my country's electricity production, supply, and sales structure has been dominated by traditional coal-fired power plants. However, with the introduction of the national strategic goal of "carbon peaking and carbon neutrality," my country is forming a new generation of power generation systems with a high proportion of renewable energy.

[0003] Research on the load regulation capacity of traditional coal-fired power generating units mainly focuses on two aspects. On the one hand, it aims to improve the load regulation capacity by making full use of the unit's own energy storage characteristics; on the other hand, it aims to enhance the unit's load regulation capacity by configuring additional energy storage or thermal storage devices.

[0004] Energy storage technology, as a flexible and adjustable resource with rapid response across multiple time scales, can quickly process power and migrate energy storage according to demand, making it an important means to promote the large-scale consumption of new energy sources. Energy storage comes in various types, and can be divided into power storage and energy storage based on their charge and discharge performance characteristics. Power storage, represented by flywheel energy storage and supercapacitors, boasts high power density and fast response speed, but suffers from low energy density, short charge and discharge times, and high self-discharge rates. Energy storage, represented by pumped hydro storage and compressed air storage, offers large storage capacity, long charge and discharge times, and long service life, but also faces challenges such as slow response speed, low power density, and difficulties in site selection.

[0005] Hydrogen energy, as a readily available, green, low-carbon, and widely applicable secondary energy source, is gradually becoming one of the important carriers for transformation and development. In areas rich in new energy sources, surplus energy is used to electrolyze water to produce hydrogen, converting electrical energy into hydrogen energy for storage. When needed, it is released by converting hydrogen energy back into electricity through fuel cells. Compared with other conventional energy storage technologies, this energy storage method has significant advantages in terms of low carbon emissions, cleanliness, energy density, and storage time. It also performs better in key indicators such as response speed, operational life, system efficiency, and operation and maintenance costs.

[0006] Therefore, given my country's power production, supply, and sales structure, which is dominated by coal-fired power, and under the "dual carbon" target, it is essential to strengthen the research and application of energy storage coupled with coal-fired power unit technology. Under this premise, how to achieve both improved energy performance, deep boiler peak shaving, and the absorption of more renewable energy sources, while significantly reducing carbon dioxide emissions, is a key focus and challenge in the energy sector today. Utility Model Content

[0007] Therefore, the purpose of this utility model is to provide a deep peak shaving system for fuel cell energy storage coupled with coal-fired power units, which aims to provide a new energy storage coupling technology that can both achieve deep peak shaving of boilers and absorb more new energy sources.

[0008] In addition, the fuel cell energy storage coupled coal-fired power unit deep peak shaving system provided by this utility model can also solve the problem of large amounts of carbon dioxide generated by coal-fired power generation.

[0009] In order to achieve the above-mentioned objectives of this utility model, the present utility model adopts the following technical solution:

[0010] A fuel cell energy storage coupled coal-fired power unit deep peak shaving system includes a new energy generator set, a coal-fired generator set, a fuel cell energy storage device, and a control system. The coal-fired generator set includes a coal-fired boiler and a generator, and the new energy generator set includes a new energy generator.

[0011] The fuel cell energy storage device includes a molten carbonate fuel cell, which has a cathode side and an anode side. The gas supply end of the cathode side is connected to a flue gas desulfurization mixer to mix the desulfurized coal-fired boiler exhaust gas with compressed fresh air and supply it to the cathode side. The gas supply end of the anode side is connected to the hydrogen-rich synthesis gas output from the first exhaust end of an external reformer, and the hydrogen-rich synthesis gas supplies the anode side. The exhaust end of the cathode side is connected to a flue gas heat exchanger to preheat the mixed gas entering the cathode side with the high-temperature exhaust gas flow from the cathode side. The high-temperature exhaust gas flow from the anode side is compressed and introduced into the first air inlet of the combustion chamber. The second air inlet of the combustion chamber is connected to an external air supply... The supply of pure oxygen is connected to the combustion chamber to burn the high-temperature waste gas flow from the anode with pure oxygen. The high-temperature waste gas flow output from the combustion chamber is introduced into the heat recovery steam generation unit and the natural gas heat exchanger in the order of heat exchange. This is to form high-temperature steam in the heat recovery steam generation unit and high-temperature natural gas in the natural gas heat exchanger. The high-temperature steam and high-temperature natural gas are simultaneously input into the reactor of the external reformer. After the reactor reaction, hydrogen-rich synthesis gas is output from the first exhaust end of the external reformer to supply gas to the anode side. At the same time, the high-temperature waste gas flow from the combustion chamber after heat exchange is input into the external reformer for heating, and the reaction mixture waste gas flow from the external reformer is discharged through the second exhaust end of the external reformer.

[0012] The control system includes a controller that communicates with the new energy generator set to obtain the output power of the new energy generator in real time; the controller also communicates with the coal-fired generator set to obtain the generator output power and unit load of the coal-fired generator set in real time; the controller also communicates with the power grid system to obtain the grid's electricity demand in real time; furthermore, the controller communicates with the fuel input control valves configured on the cathode and anode sides of the molten carbonate fuel cell in the fuel cell energy storage device to monitor the fuel input at the anode and cathode in real time. The controller also obtains the output voltage and current of the molten carbonate fuel cell in real time, thereby controlling the output power of the molten carbonate fuel cell to ensure that during peak electricity demand, the controller controls the fuel cell energy storage device to participate in deep peak shaving of the coal-fired unit; during off-peak electricity demand, the controller controls the excess electricity output by the new energy generator set to be used for hydrogen production by water electrolysis.

[0013] Furthermore, the exhaust gas from the coal-fired boiler is fed into a flue gas desulfurizer, and after desulfurization, it is introduced into a flue gas desulfurization mixer. At the same time, fresh air is also introduced into the flue gas desulfurization mixer after being compressed by an air compressor, in order to dilute the exhaust gas from the coal-fired boiler with fresh air.

[0014] Furthermore, the molten carbonate fuel cell is placed downstream of a coal-fired boiler, and a flue gas heat exchanger is provided between the flue gas desulfurization mixer and the cathode side.

[0015] Furthermore, an anode high-temperature exhaust gas compressor is provided between the exhaust end on the anode side and the combustion chamber.

[0016] Furthermore, the second air inlet of the combustion chamber is connected to an external pure oxygen storage tank, and an oxygen compressor and an oxygen heat exchanger are respectively configured on the connecting pipe between the external pure oxygen storage tank and the second air inlet of the combustion chamber. High-temperature hydrogen-rich synthesis gas is input into the input end of the oxygen heat exchanger to perform high-temperature heat exchange on the low-temperature pure oxygen entering the oxygen heat exchanger. After the heat exchange is completed, the hydrogen-rich synthesis gas is supplied to the anode side, and at the same time, the pure oxygen after the heat exchange is completed is introduced into the combustion chamber.

[0017] Furthermore, the heat recovery steam generation unit includes a three-stage heat exchanger: a high-pressure heat exchanger, a medium-pressure heat exchanger, and a low-pressure heat exchanger. The input end of the medium-pressure heat exchanger is supplied with a high-temperature combustion waste gas stream to exchange heat with the water medium in the medium-pressure heat exchanger. The resulting steam is then piped to one side of the steam-water separator. Simultaneously, the input end of the low-pressure heat exchanger is supplied with a high-temperature combustion waste gas stream to exchange heat with the low-temperature compressed air in the low-pressure heat exchanger. The resulting air is then piped to the other side of the steam-water separator. The steam separated by the steam-water separator is piped to the high-pressure heat exchanger, where the high-temperature combustion waste gas stream is used to perform high-temperature heat exchange on the separated steam before it is fed into an external reformer.

[0018] Furthermore, the input end of the natural gas heat exchanger is introduced with high-temperature exhaust gas from combustion to exchange heat with the low-temperature compressed natural gas in the natural gas heat exchanger. After the heat exchange is completed, the high-temperature natural gas formed is input into the external reformer through a pipeline.

[0019] Preferably, the reaction mixture exhaust gas discharged from the second exhaust end of the external reformer is introduced into the pressure swing adsorption separator, and the carbon dioxide obtained by pressure swing adsorption separation is compressed and stored in the carbon dioxide storage device.

[0020] More preferably, the control system further includes several data acquisition sensors, which respectively collect the generator output power of the coal-fired generator set, the load of the coal-fired generator set, the main steam pressure, the output temperature of the coal-fired generator set, the output power of the new energy generator, the input amount of anode and cathode fuel, and the output voltage and current of the molten carbonate fuel cell.

[0021] Furthermore, the controller also includes a PID control module. The PID control module uses the acquired generator output power, coal-fired unit load, main steam pressure and coal-fired unit output temperature, and adjusts the input fuel quantity of the molten carbonate fuel cell according to the power grid demand, thereby realizing the control of the output power generation of the fuel cell energy storage device.

[0022] The beneficial effects of this utility model are:

[0023] This utility model provides a fuel cell energy storage coupled with a coal-fired power unit deep peak shaving system, which can adjust the output power and operating status of the fuel cell energy storage device according to the electricity load demand and the operating status of the coal-fired power generation unit. During off-peak hours, excess electricity is used to produce and store hydrogen-containing fuel. During peak hours, the fuel cell energy storage device is activated. The anode side is supplied with hydrogen-rich synthesis gas generated from natural gas in an external reformer, and the cathode side is fed with existing boiler exhaust gas after desulfurization, fresh air dilution, and preheating. The electricity generated by the reaction of hydrogen and oxygen is delivered to the coal-fired power generation unit to help the unit flexibly shave peak loads. In addition, through the consumption of CO2 storage and molten carbonate fuel cells, a certain degree of carbon capture and utilization is achieved.

[0024] This invention achieves an organic combination of new energy power generation and thermal power generation by coupling a fuel cell energy storage device with a coal-fired power unit, improving the stability and power supply quality of the power grid and overcoming the problems of instability and unsustainability of new energy power generation. The fuel cell energy storage device can release electrical energy when the coal-fired power unit needs peak shaving, improving the operational flexibility, peak shaving capability, and energy utilization efficiency of the coal-fired power unit. The fuel cell energy storage device uses carbon dioxide in the flue gas as the cathode input, consumes part of the carbon dioxide, and adds carbon dioxide compression and storage devices to realize the storage and utilization of carbon dioxide, achieving the low-carbon goal. The control system monitors various parameters of the molten carbonate fuel cell, the coal-fired power unit, and the new energy power unit in real time, such as generator output power, battery current output, temperature, and pressure, and uses a PID control module to determine the output power of the fuel cell energy storage device to achieve deep peak shaving of the coal-fired power unit. The remaining fuel in the anode exhaust of the fuel cell energy storage device is burned in 98% pure oxygen provided by the air separation device, and the heat generated is provided to the heat recovery steam generation unit to achieve fuel preheating and simultaneously supply heat to the external reformer, eliminating the need for a heating stack for the reforming reaction. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the composition of the fuel cell energy storage coupled coal-fired power unit deep peak shaving system provided by this utility model. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] This utility model provides a deep peak-shaving system for fuel cell energy storage coupled with a coal-fired power unit. It couples a new energy power generation unit to an existing coal-fired power generation unit, adding a fuel cell energy storage device and a control system. When there is excess new energy generation, water is electrolyzed to store hydrogen; when power generation is needed, the control system activates the fuel cell energy storage device, allowing hydrogen to react with oxygen in the air to generate electricity, which is then delivered to the coal-fired power generation unit, achieving deep peak-shaving capability. Furthermore, addressing the issue of large amounts of carbon dioxide generated by the coal-fired power generation unit, the fuel cell energy storage device is optimized, using carbon dioxide as an input condition for fuel cell operation and adding it to a compressed storage device to achieve carbon dioxide capture and utilization.

[0029] like Figure 1 As shown, a fuel cell energy storage coupled with a coal-fired power unit deep peak-shaving system includes a new energy generator set, a coal-fired generator set, a fuel cell energy storage device, and a control system. The coal-fired generator set includes a coal-fired boiler and a generator, and the new energy generator set includes a new energy generator. The fuel cell energy storage device includes a molten carbonate fuel cell, which includes a cathode side and an anode side.

[0030] When the power grid's electricity demand is at its peak, meaning that the combined power generation of coal-fired power plants and renewable energy power plants cannot meet the demand, the fuel cell energy storage coupled with the coal-fired power plant deep peak shaving system will activate the fuel cell energy storage device and transmit the generated electricity to the coal-fired power plant, thus achieving deep peak shaving for the coal-fired power plant. Under this premise, the workflow of the fuel cell energy storage coupled with the coal-fired power plant deep peak shaving system is as follows:

[0031] The exhaust gas from the coal-fired boiler is fed into the flue gas desulfurizer 1, and after desulfurization, it is introduced into the flue gas desulfurization mixer 2. At the same time, fresh air is also introduced into the flue gas desulfurization mixer 2 after being compressed by the air compressor 3, in order to dilute the exhaust gas from the coal-fired boiler.

[0032] A molten carbonate fuel cell 4 is placed downstream of a coal-fired boiler, and a flue gas heat exchanger 5 is provided between the flue gas desulfurization mixer 2 and the cathode side 41. The gas supply end of the cathode side 41 is connected to the flue gas desulfurization mixer 2 to mix the desulfurized coal-fired boiler exhaust gas with compressed fresh air and supply it to the cathode side; the gas supply end of the anode side 42 is connected to the hydrogen-rich synthesis gas output from the first exhaust end of the external reformer 11, and the hydrogen-rich synthesis gas supplies the anode side; the exhaust end of the cathode side 41 is connected to the flue gas heat exchanger 5 to preheat the mixed gas entering the cathode side with the cathode high-temperature exhaust gas output from the cathode side; the anode high-temperature exhaust gas output from the anode side 42 is compressed and introduced into the first air inlet of the combustion chamber 7, and the second air inlet of the combustion chamber 7 is connected to externally supplied pure oxygen for combustion of the anode high-temperature exhaust gas and pure oxygen in the combustion chamber 7.

[0033] In this embodiment, an anode high-temperature exhaust gas compressor 6 is provided between the exhaust end of the anode side 42 and the combustion chamber 7; at the same time, the second air inlet of the combustion chamber 7 is connected to an external pure oxygen storage tank 12, and an oxygen compressor 13 and an oxygen heat exchanger 14 are respectively arranged on the connecting pipe between the external pure oxygen storage tank 12 and the second air inlet of the combustion chamber 7. The input end of the oxygen heat exchanger 14 is supplied with high-temperature hydrogen-rich synthesis gas, which performs high-temperature heat exchange on the low-temperature pure oxygen entering the oxygen heat exchanger 14. After the heat exchange is completed, the hydrogen-rich synthesis gas is supplied to the anode side 42, and the pure oxygen after the heat exchange is completed is introduced into the combustion chamber 7.

[0034] Next, the high-temperature exhaust gas from the combustion chamber 7 is introduced into the heat recovery steam generation unit 8 and the natural gas heat exchanger 10 in the order of heat exchange, so as to form high-temperature steam in the heat recovery steam generation unit 8 and high-temperature natural gas in the natural gas heat exchanger 10. The high-temperature steam and high-temperature natural gas are simultaneously input into the reactor of the external reformer 11. After the reactor reaction, hydrogen-rich synthesis gas is output from the first exhaust end of the external reformer 11 to supply gas to the anode side 42. At the same time, the high-temperature exhaust gas from the combustion after heat exchange is input into the external reformer 11 for heating, and the reaction mixture exhaust gas from the external reformer 11 is discharged through the second exhaust end of the external reformer 11. The reaction mixture exhaust gas discharged from the second exhaust end is introduced into the pressure swing adsorption separator 15. The carbon dioxide obtained by pressure swing adsorption separation is compressed and stored in the carbon dioxide storage device 16.

[0035] Here, the heat recovery steam generation unit 8 in this example includes a three-stage heat exchanger: a high-pressure heat exchanger 81, a medium-pressure heat exchanger 82, and a low-pressure heat exchanger 83. The input end of the medium-pressure heat exchanger 82 receives a high-temperature combustion waste gas stream to exchange heat with the medium water in the medium-pressure heat exchanger 82. After the heat exchange, the resulting steam is piped to one side of the steam-water separator 84. Simultaneously, the input end of the low-pressure heat exchanger 83 receives a high-temperature combustion waste gas stream to exchange heat with the low-temperature compressed air in the low-pressure heat exchanger 83. After the heat exchange, the steam... The generated air is piped to the other side of the steam-water separator 84; the water vapor separated by the steam-water separator 84 is piped to the high-pressure heat exchanger 81, where it undergoes high-temperature heat exchange with the combustion high-temperature exhaust gas introduced into the high-pressure heat exchanger 81 before being input into the external reformer 11; simultaneously, combustion high-temperature exhaust gas is introduced into the input end of the natural gas heat exchanger 10 to exchange heat with the low-temperature compressed natural gas in the natural gas heat exchanger 10, and the resulting high-temperature natural gas is piped to the external reformer 11. It should be noted that the low-temperature natural gas is compressed using the natural gas compressor 9.

[0036] In this example, high-temperature natural gas and high-temperature steam are simultaneously introduced into the reactor of the external reformer 11, i.e., a methane steam reforming (SMR) reaction occurs in the external reformer 11. This is a traditional and important route for producing hydrogen-rich syngas, a relatively mature industrial hydrogen production process, and also the simplest and most economical method for hydrogen production. The SMR process is a reversible endothermic reaction, generally requiring high temperatures, and is accompanied by CO vapor-water conversion during the reaction.

[0037] CH4 + H2O = CO + 3H2

[0038] CO + H₂O = CO₂ + H₂

[0039] Meanwhile, the controller 17 in the control system communicates with the new energy generator set to obtain the output power of the new energy generator in real time; the controller 17 also communicates with the coal-fired generator set to obtain the generator output power and unit load of the coal-fired generator set in real time. At the same time, the controller 17 also communicates with the power grid system to obtain the power demand of the grid in real time. In addition, the controller 17 also communicates with the fuel input control valves configured on the cathode side 41 and anode side 42 of the molten carbonate fuel cell 4 in the fuel cell energy storage device to monitor the fuel input of the anode and cathode in real time. The controller 17 also obtains the output voltage and current of the molten carbonate fuel cell 4 in real time, and then controls the output power of the molten carbonate fuel cell 4 to ensure that during peak electricity demand, the controller 17 controls the fuel cell energy storage device to participate in the deep peak shaving of the coal-fired unit.

[0040] In this example, the control system also includes several data acquisition sensors, which respectively collect the generator output power of the coal-fired generator set, the load of the coal-fired generator set, the main steam pressure, the output temperature of the coal-fired generator set, the output power of the new energy generator, the input amount of anode and cathode fuel, and the output voltage and current of the molten carbonate fuel cell.

[0041] In addition, the controller 17 also includes a PID control module. This PID control module utilizes the acquired generator output power, coal-fired unit load, main steam pressure, and coal-fired unit output temperature, and adjusts the input fuel quantity of the molten carbonate fuel cell according to the grid's power demand, thereby controlling the output power generation of the fuel cell energy storage device. The model of this PID control module is XSC8-BT3CA1B1A1V0.

[0042] When the grid's electricity demand is at its lowest point, meaning that the electricity generated by renewable energy generators exceeds the demand, it's important to note that the electricity generated by renewable energy generators is unstable and unpredictable; sometimes more is generated, sometimes less. Furthermore, coal-fired power plants, as a traditional power generation technology, are relatively easy to control. In this example, the excess electricity during periods of low demand refers only to the surplus generated by renewable energy generators.

[0043] At this time, during the off-peak electricity demand, the controller 17 controls the excess electrical energy output by the new energy generator in the new energy generator set to be sent to the electrolyzer 19 through the rectifier 18, so as to decompose water into hydrogen and oxygen for use in the electrolysis of water to produce hydrogen, thereby realizing the subsequent "electricity-hydrogen-electricity" operation mode and solving the problems of instability and unsustainability of new energy.

[0044] In addition, the hydrogen produced by water electrolysis can not only regulate the flow rate of hydrogen entering the anode side 42 of the molten carbonate fuel cell 4 through the regulating valve, but also supplement the hydrogen-rich syngas during peak electricity consumption, and can also store excess hydrogen to prepare hydrogen-containing fuels.

[0045] The above are merely embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A fuel cell energy storage coupled with a coal-fired power unit deep peak-shaving system, comprising a new energy generator set and a coal-fired generator set, wherein the coal-fired generator set includes a coal-fired boiler and a generator, and the new energy generator set includes a new energy generator, characterized in that, The system also includes: a fuel cell energy storage device and a control system, wherein: The fuel cell energy storage device includes a molten carbonate fuel cell, which has a cathode side and an anode side. The gas supply end of the cathode side is connected to a flue gas desulfurization mixer to mix the desulfurized coal-fired boiler exhaust gas with compressed fresh air and supply it to the cathode side. The gas supply end of the anode side is connected to the hydrogen-rich synthesis gas output from the first exhaust end of an external reformer, and the hydrogen-rich synthesis gas supplies the anode side. The exhaust end of the cathode side is connected to a flue gas heat exchanger to preheat the mixed gas entering the cathode side with the high-temperature exhaust gas flow from the cathode side. The high-temperature exhaust gas flow from the anode side is compressed and introduced into the first air inlet of the combustion chamber. The second air inlet of the combustion chamber is connected to an external air supply... The supply of pure oxygen is connected to the combustion chamber to burn the high-temperature waste gas from the anode with pure oxygen. The high-temperature waste gas output from the combustion chamber is introduced into the heat recovery steam generation unit and the natural gas heat exchanger in the order of heat exchange. This is to form high-temperature steam in the heat recovery steam generation unit and high-temperature natural gas in the natural gas heat exchanger. The high-temperature steam and high-temperature natural gas are simultaneously input into the reactor of the external reformer. After the reactor reaction, hydrogen-rich synthesis gas is output from the first exhaust end of the external reformer to supply gas to the anode side. At the same time, the high-temperature waste gas from the combustion chamber after heat exchange is input into the external reformer for heating, and the reaction mixture waste gas from the external reformer is discharged through the second exhaust end of the external reformer. The control system includes a controller that communicates with the new energy generator set to obtain the output power of the new energy generator in real time; the controller also communicates with the coal-fired generator set to obtain the generator output power and unit load of the coal-fired generator set in real time; the controller also communicates with the power grid system to obtain the grid's electricity demand in real time; furthermore, the controller communicates with the fuel input control valves configured on the cathode and anode sides of the molten carbonate fuel cell in the fuel cell energy storage device to monitor the fuel input at the anode and cathode in real time. The controller also obtains the output voltage and current of the molten carbonate fuel cell in real time, thereby controlling the output power of the molten carbonate fuel cell to ensure that during peak electricity demand, the controller controls the fuel cell energy storage device to participate in deep peak shaving of the coal-fired unit; during off-peak electricity demand, the controller controls the excess electricity output by the new energy generator set to be used for hydrogen production by water electrolysis.

2. The fuel cell energy storage coupled coal-fired power unit deep peak shaving system according to claim 1, characterized in that: The exhaust gas from the coal-fired boiler is fed into a flue gas desulfurizer, and after desulfurization, it is introduced into a flue gas desulfurization mixer. At the same time, fresh air is also introduced into the flue gas desulfurization mixer after being compressed by an air compressor, in order to dilute the exhaust gas from the coal-fired boiler.

3. The fuel cell energy storage coupled coal-fired power unit deep peak shaving system according to claim 2, characterized in that: The molten carbonate fuel cell is located downstream of a coal-fired boiler, and a flue gas heat exchanger is provided between the flue gas desulfurization mixer and the cathode side.

4. The fuel cell energy storage coupled coal-fired power unit deep peak shaving system according to claim 3, characterized in that: An anode high-temperature exhaust gas compressor is installed between the exhaust end on the anode side and the combustion chamber.

5. The fuel cell energy storage coupled coal-fired power unit deep peak shaving system according to claim 1, characterized in that: The second air inlet of the combustion chamber is connected to an external pure oxygen storage tank. An oxygen compressor and an oxygen heat exchanger are respectively installed on the connecting pipe between the external pure oxygen storage tank and the second air inlet of the combustion chamber. High-temperature hydrogen-rich synthesis gas is input into the input end of the oxygen heat exchanger to perform high-temperature heat exchange on the low-temperature pure oxygen entering the oxygen heat exchanger. After the heat exchange is completed, the hydrogen-rich synthesis gas is supplied to the anode side, and at the same time, the pure oxygen after the heat exchange is completed is introduced into the combustion chamber.

6. The fuel cell energy storage coupled coal-fired power unit deep peak shaving system according to claim 5, characterized in that: The heat recovery steam generation unit includes three heat exchangers: a high-pressure heat exchanger, a medium-pressure heat exchanger, and a low-pressure heat exchanger. The input end of the medium-pressure heat exchanger is supplied with high-temperature combustion waste gas to exchange heat with the water medium in the medium-pressure heat exchanger. The resulting steam is piped to one side of a steam-water separator. Simultaneously, the input end of the low-pressure heat exchanger is supplied with high-temperature combustion waste gas to exchange heat with the low-temperature compressed air in the low-pressure heat exchanger. The resulting air is piped to the other side of the steam-water separator. The steam separated by the steam-water separator is piped to the high-pressure heat exchanger, where the high-temperature combustion waste gas is used to exchange heat with the separated steam before it is fed into an external reformer.

7. The fuel cell energy storage coupled coal-fired power unit deep peak shaving system according to claim 6, characterized in that: The high-temperature exhaust gas from combustion is introduced into the input end of the natural gas heat exchanger to exchange heat with the low-temperature compressed natural gas in the natural gas heat exchanger. After the heat exchange is completed, the high-temperature natural gas formed is input into the external reformer through a pipeline.

8. The fuel cell energy storage coupled coal-fired power unit deep peak shaving system according to claim 7, characterized in that: The reaction mixture exhaust gas discharged from the second exhaust end of the external reformer is introduced into the pressure swing adsorption separator. The carbon dioxide obtained by pressure swing adsorption separation is compressed and stored in the carbon dioxide storage device.

9. The fuel cell energy storage coupled coal-fired power unit deep peak shaving system according to claim 1, characterized in that: The control system also includes several data acquisition sensors, which respectively collect the generator output power of the coal-fired generator set, the load of the coal-fired generator set, the main steam pressure, the output temperature of the coal-fired generator set, the output power of the new energy generator, the input amount of anode and cathode fuel, and the output voltage and current of the molten carbonate fuel cell.

10. The fuel cell energy storage coupled coal-fired power unit deep peak shaving system according to claim 1, characterized in that: The controller also includes a PID control module. The PID control module uses the acquired generator output power, coal-fired unit load, main steam pressure and coal-fired unit output temperature, and adjusts the input fuel quantity of the molten carbonate fuel cell according to the power grid demand, thereby realizing the control of the output power generation of the fuel cell energy storage device.

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