Fuel cell auxiliary steam-electricity double-drive thermal power plant rapid load increasing system and method

Abstract

The invention belongs to the technical field of comprehensive utilization of energy, and provides a rapid load increasing system and method for a fuel-cell-assisted steam-electricity double-drive thermal power plant. According to the technical scheme, a thermoelectric conversion module comprises a water supply heat regeneration system and a flue gas and air system; the feed water regenerative system comprises a feed water pump, a water pump small steam turbine and a water pump motor which are connected in sequence; the flue gas and air system comprises an induced draft fan, an induced draft fan small steam turbine and an induced draft fan motor which are connected in sequence; the water pump motor and the induced draft fan motor are connected and then connected to the hydrogen energy auxiliary power generation and combustion-supporting module; the hydrogen energy auxiliary power generation and combustion-supporting module comprises a fuel cell and an oxygen reinjection pipeline, a hydrogen pipeline of the fuel cell is connected to the hydrogen energy production and storage module, and a direct current output end is connected with an inverter and connected into a power supply loop of a water pump motor and an induced draft fan motor; the hydrogen energy production and storage module is connected to the steam turbine-generator system through an electrical circuit and connected to the thermoelectric conversion module through an oxygen reinjection pipeline. The inertia constraint of a traditional thermodynamic system is broken through.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive energy utilization technology, and in particular relates to a rapid load increase system and method for thermal power plants with fuel cell-assisted dual-drive steam and electric power. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With a high proportion of renewable energy being connected to the grid, the inherent limitations of traditional thermal power, especially coal-fired units, in terms of operational flexibility, energy efficiency, and environmental impact are becoming increasingly prominent, and have become a technical bottleneck restricting the construction of new power systems and the large-scale consumption of renewable energy.

[0004] Insufficient peak-shaving capacity of thermal power units is one of their core challenges. Combined heat and power (CHP) units account for a high proportion of power generation, and during the winter heating season, they often operate on a "heat-driven power generation" model, severely limiting the range of power output regulation and making it difficult to flexibly and quickly adjust according to the real-time load demand of the power grid. When the output of intermittent renewable energy sources such as wind and solar power surges, thermal power units cannot quickly reduce their load to make room for them, easily leading to "wind and solar curtailment." Conversely, when renewable energy output drops sharply, thermal power units cannot quickly increase their load to compensate for the power deficit, directly threatening the stable operation of the power grid. This lag in response and lack of regulation capacity makes it difficult for traditional thermal power to fully meet the ever-increasing peak-shaving demands of the power system.

[0005] Traditional thermal power plants generally have low energy conversion efficiency, resulting in significant energy waste. During the conversion of fuel's chemical energy into electrical energy, coal-fired units generate a large amount of low-grade waste heat, which is typically discharged directly into the environment through cooling systems. This unutilized waste heat not only represents energy waste but also exacerbates environmental thermal pollution. Although some units have adopted measures such as regenerative systems, there is still considerable room for improvement in their overall energy utilization efficiency.

[0006] The coal-fired power generation structure faces dual pressures from both resources and the environment. Coal is a non-renewable resource, and its large-scale consumption is crucial to national energy security. More seriously, the combustion of coal produces large amounts of pollutants such as carbon dioxide, sulfur oxides, nitrogen oxides, and dust, which are major sources of greenhouse gas emissions and air pollution, contradicting the direction of green and low-carbon development.

[0007] To address these challenges, the integration of thermal power and new energy sources is being vigorously promoted. However, simply coupling them together does not fundamentally solve the persistent problems of slow response and low energy efficiency in thermal power units. In particular, the massive thermal system of boiler-turbine-generator has enormous thermal inertia, and its load-up rate is strictly constrained by the performance of key auxiliary equipment (such as induced draft fans and feedwater pumps).

[0008] Therefore, there is an urgent need for an innovative technological solution that can break through the inertia of traditional thermal systems, fully tap the peak-shaving potential of thermal power units, and significantly improve their overall energy utilization efficiency, thereby enhancing the grid's ability to absorb renewable energy and promoting the clean and low-carbon transformation of the energy structure. Summary of the Invention

[0009] To address at least one of the technical problems mentioned above, the first aspect of this invention provides a rapid load-up system for thermal power plants with fuel cell-assisted steam-electric dual drive, which enables rapid load-up of thermal power units within minutes: by directly powering key auxiliary equipment through fuel cells and combining it with oxygen-assisted combustion, it fundamentally breaks through the limitation of the load-up rate on the huge thermal inertia of the boiler-turbine system, enabling coal-fired units to have a rapid response capability close to that of gas turbine units, and greatly improving the peak-shaving security of the power grid.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: A fuel cell-assisted dual-drive rapid load increase system for thermal power plants includes a thermoelectric conversion module, a hydrogen production and storage module, and a hydrogen-assisted power generation and combustion support module. The thermoelectric conversion module includes a feedwater regeneration system and a flue gas system. The feedwater regeneration system includes a feedwater pump, a small steam turbine, and a pump motor connected in sequence. The flue gas system includes an induced draft fan, a small steam turbine, and an induced draft fan motor connected in sequence. The pump motor and the induced draft fan motor are connected to the hydrogen-assisted power generation and combustion support module. The hydrogen-assisted power generation and combustion module includes a fuel cell and an oxygen reinjection pipeline. The hydrogen pipeline of the fuel cell is connected to the hydrogen production and storage module. The DC output terminal is connected to an inverter, which converts the DC power into AC power and then connects it to the power supply circuit of the water pump motor and the induced draft fan motor. The hydrogen production and storage module is connected to the turbine-generator system via electrical lines and to the thermoelectric conversion module via an oxygen reinjection pipeline.

[0011] As a further embodiment, the thermoelectric conversion module also includes a boiler system and a turbine-generator system, wherein the boiler system, turbine-generator system, feedwater regeneration system and flue gas system are connected in sequence; the turbine-generator system includes a main turbine, a generator and a condenser. The high-temperature and high-pressure steam generated by the boiler system drives the blades of the main turbine to rotate, which drives the coaxial generator to cut magnetic field lines to generate electricity. The exhaust steam after doing work is condensed into water in the condenser and then heated in stages by the feedwater regeneration system and transported back to the boiler system.

[0012] As a further embodiment, the hydrogen energy production and storage module includes an electrolyzer, a hydrogen storage tank, and an oxygen storage tank. The input end of the electrolyzer is connected to the power plant generator outlet or the plant power bus via an electrical line. The hydrogen storage tank and the oxygen storage tank are respectively connected to the hydrogen and oxygen outlets of the electrolyzer via pipelines.

[0013] As a further embodiment, pressure regulators are installed on the outlet pipelines of both the hydrogen storage tank and the oxygen storage tank, and the hydrogen pipeline of the fuel cell is connected to the pressure regulator at the outlet of the hydrogen storage tank.

[0014] As a further embodiment, the hydrogen-assisted power generation and combustion module also includes a booster and an air filter, wherein the air end of the fuel cell is connected to one end of the air filter, and the other end of the air filter is connected to the booster.

[0015] As a further implementation, the fuel cell integrates a heat exchanger through which cold water flows to absorb the waste heat generated during the fuel cell power generation process. After being heated into hot water, the water is transported to the plant's hot water network for heating or domestic hot water supply.

[0016] As a further embodiment, the hydrogen storage tank and the oxygen storage tank are high-pressure containers.

[0017] To address at least one of the technical problems existing in the background art described above, a second aspect of the present invention provides a method for operating a fuel cell-assisted dual-drive system for rapid load increase in thermal power plants. To achieve the above objective, the present invention adopts the following technical solution: The operating method of a fuel cell-assisted dual-drive (gasoline and electric) rapid load increase system for thermal power plants includes: When the power grid is in a period of low load demand, the thermoelectric conversion module is controlled to reduce its output and transmit some of the surplus power generated by the generator to the hydrogen production and storage module. The hydrogen production and storage module uses the surplus power to electrolyze water to produce hydrogen and oxygen. Under this condition, the induced draft fan and the feedwater pump are driven by their corresponding small steam turbines. When the power grid requires a rapid increase in load, the hydrogen-assisted power generation and combustion-supporting module is activated, specifically including: Hydrogen from the hydrogen production and storage module is fed into the fuel cell for an electrochemical reaction to generate electricity, which is then directly supplied to the drive motors of the induced draft fan and the water pump; oxygen is delivered to the thermoelectric conversion module for combustion support. The driving mode of the induced draft fan and the water supply pump is switched from being mainly driven by steam to being mainly driven by electric power supplied by the fuel cell or a pure electric drive mode. The speed of the induced draft fan and the water supply pump is quickly increased by the corresponding electric motor to match the combustion process enhanced by oxygen-assisted combustion.

[0018] As a further implementation, a high-load steady-state operation step is also included: when the thermoelectric conversion module is operating under high load steady-state conditions, the power supply to the electrolytic cell is cut off, and the generator output is supplied entirely to the power grid; the hydrogen storage tank and oxygen storage tank maintain gas storage pressure and are in standby mode.

[0019] As a further implementation, a load reduction switching step is also included: when a command to reduce output is received, the conventional power conversion module is controlled to reduce output; after the power stabilizes at a low load value, the surplus power is transmitted to the electrolytic cell again for electrolysis to produce hydrogen and oxygen, while the drive mode of the induced draft fan and the feedwater pump is switched back to be driven by the small steam turbine.

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention directly powers key auxiliary equipment through fuel cells and combines oxygen-assisted combustion, fundamentally breaking through the limitation of the load increase rate on the huge thermal inertia of the boiler-turbine system. This enables coal-fired units to have a rapid response capability close to that of gas-fired units, greatly improving the peak-shaving security of the power grid and realizing minute-level rapid load increase of thermal power units.

[0021] 2. This invention achieves flexible operation of thermal power units under different load conditions through a complete cycle of hydrogen energy production, storage, and utilization, as well as a dual-drive steam-electric design for key auxiliary equipment. At low loads, surplus electricity is used to produce hydrogen, while at high loads, stored hydrogen energy is used to rapidly increase unit output. Simultaneously, waste heat recovery improves overall energy utilization efficiency, reducing the plant's net power consumption and overall energy consumption.

[0022] 3. This invention enhances the grid's ability to absorb renewable energy: This system enables thermal power units to perform deep peak shaving more flexibly, freeing up more space for intermittent renewable energy sources such as wind and solar power to be connected to the grid. It can also quickly fill the gap when renewable energy output drops sharply, smoothing out power fluctuations, making it an effective technical solution to support the stable operation of a high-proportion renewable energy power system.

[0023] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0025] Figure 1 This is a schematic diagram of the structure of a fuel cell-assisted dual-drive system for rapid load increase in thermal power plants according to an embodiment of the present invention; The components include: 1. Boiler body; 2. Furnace; 3. Main steam turbine; 4. Generator; 5. Condenser; 6. Feedwater pump; 7. Low-pressure heater; 8. High-pressure heater; 9. Induced draft fan; 10. Flue; 11. Feedwater pump turbine; 12. Feedwater pump motor; 13. Induced draft fan turbine; 14. Induced draft fan motor; 15. Electrolytic cell; 16. Hydrogen storage tank; 17. Oxygen storage tank. 18. Pressure regulator; 19. Fuel cell; 20. Oxygen reinjection line; 21. Boost compressor; 22. Air filter. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] In this invention, terms such as "connected" and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0030] Example 1 Reference Figure 1 The fuel cell-assisted dual-drive rapid load increase system for thermal power plants in this embodiment includes a thermoelectric conversion module, a hydrogen production and storage module, and a hydrogen-assisted power generation and combustion module. The thermoelectric conversion module includes a boiler system, a steam turbine-generator system, a feedwater regeneration system, and a flue gas system connected in sequence. The boiler system includes a boiler body 1 and a furnace 2. In this embodiment, the boiler body includes heating surfaces such as water-cooled walls, superheaters, reheaters, and economizers, which are not shown in the figure. Fuel (such as pulverized coal) is burned in the furnace to release heat and heat the working medium.

[0031] The steam turbine-generator system includes a main steam turbine 3, a generator 4, and a condenser 5. The high-temperature and high-pressure steam generated by the boiler system drives the blades of the main steam turbine 3 to rotate, which in turn drives the coaxial generator 4 to cut magnetic field lines to generate electricity. The exhaust steam after doing work is condensed into water in the condenser 5.

[0032] The feedwater regeneration system includes a feedwater pump 6, a low-pressure heater 7 and a high-pressure heater 8, which heats the condensate from the condenser in stages and sends it back to the boiler to form a complete thermodynamic cycle. The feedwater pump 6 is connected to one end of the feedwater pump turbine 11, and the other end of the feedwater pump turbine 11 is connected to the feedwater pump motor 12. In this embodiment, the drive methods for the two key auxiliary machines, the induced draft fan and the feedwater pump, are specially configured. Both devices adopt a "steam-electric dual-drive" mode, meaning they are driven by a small steam turbine and an electric motor, either jointly or alternately. The small steam turbine is connected to the steam turbine extraction system, and the electric motor is connected to the plant power system and the fuel cell output. Regarding the operation method, different operating strategies are adopted according to the grid load demand under different operating conditions. When the grid is under low load, the thermal power unit operates at reduced output, and some of the surplus electricity generated by the generator is sent to the electrolyzer. The electrolyzer electrolyzes water to produce hydrogen and oxygen, which are stored in hydrogen storage tanks and oxygen storage tanks, respectively. Under this condition, the induced draft fan and feedwater pump are mainly driven by the small steam turbine to maintain the basic operation of the system's thermodynamic cycle. When the grid requires a rapid load increase, the system initiates a rapid load increase program. At this time, hydrogen in the hydrogen storage tank, after pressure regulation, is sent to the fuel cell along with filtered and pressurized air. The fuel cell generates electrical energy through an electrochemical reaction, which is directly supplied to the drive motors of the induced draft fan and feedwater pump. Meanwhile, oxygen from the oxygen storage tank is transported to the furnace through a dedicated pipeline to be mixed with fuel as a combustion aid.

[0033] During this process, the drive mode of the induced draft fan and feedwater pump switches from primarily steam-driven to a combined steam-electric drive or pure electric drive mode. Once the electric motor receives power from the fuel cell, it can immediately drive the auxiliary equipment to its rated speed, unaffected by the limitations of the small turbine extraction parameters. The increased induced draft fan speed rapidly increases the boiler ventilation, matching the enhanced combustion intensity due to oxygen injection; the increased feedwater pump speed correspondingly increases the boiler feedwater flow, promptly absorbing the increased heat within the furnace and promoting increased steam production.

[0034] The flue gas system includes an induced draft fan 9 and a flue 10. The induced draft fan 9 is connected to the induced draft fan turbine 13 (usually driven by the main turbine) and the induced draft fan motor 14. The induced draft fan 9 is responsible for drawing the flue gas generated by the boiler combustion through the flue and discharging it into the atmosphere through the chimney to maintain the negative pressure in the furnace.

[0035] The hydrogen energy production and storage module includes an electrolyzer 15, a hydrogen storage tank 16, and an oxygen storage tank 17. The input end of the electrolyzer 15 is connected to the power plant generator outlet or the plant power bus via an electrical line so as to receive surplus power when needed. The hydrogen storage tank 16 and the oxygen storage tank 17 are respectively connected to the hydrogen and oxygen outlets of the electrolyzer 15 via pipelines. In this embodiment, the electrolytic cell 15 adopts mature alkaline electrolytic cell or proton exchange membrane electrolytic cell technology. Its function is to electrolyze water, generate hydrogen at the cathode and oxygen at the anode.

[0036] Hydrogen storage tank 16 and oxygen storage tank 17 are high-pressure containers used to store hydrogen and oxygen produced by electrolysis. To ensure safe and stable operation, pressure regulators 18 are installed on the outlet pipelines of both hydrogen storage tank 16 and oxygen storage tank 17 to reduce the pressure of the high-pressure gas in the tanks to the stable pressure required by subsequent equipment.

[0037] The hydrogen-assisted power generation and combustion module includes a fuel cell 19 and an oxygen reinjection pipeline 20; The hydrogen pipeline of fuel cell 19 is connected to the pressure regulator 18 at the outlet of hydrogen storage tank 16. The hydrogen-assisted power generation and combustion module also includes a booster compressor 21 and an air filter 22. The air end of fuel cell 19 is connected to one end of air filter 22, and the other end of air filter 22 is connected to booster compressor 21. Air is drawn from the environment by booster compressor 21, purified by air filter 22, and then sent to fuel cell 10. The DC output end of fuel cell 19 is connected to an inverter, which converts DC power to AC power and connects to the power supply circuit of induced draft fan motor 14 and feedwater pump motor 12.

[0038] Furthermore, a heat exchanger is integrated into the fuel cell 19. Cold water pipelines (e.g., from the plant's domestic water system or supplementary water system) flow through the heat exchanger, absorbing the waste heat generated during the fuel cell power generation process. After being heated into hot water, it is transported to the plant's hot water network for heating or domestic hot water supply.

[0039] This invention features high system integration and relatively controllable retrofit costs: The solution is an incremental upgrade based on existing mature thermal power units, primarily adding hydrogen-related equipment and upgrading auxiliary drive systems. It requires no radical modifications to main equipment such as boilers and turbines, making it technically feasible and economically viable. It also offers certain environmental benefits: by using green hydrogen (prepared from surplus renewable energy or off-peak electricity) to assist power generation and combustion, the consumption of fossil fuels and corresponding carbon dioxide emissions can be reduced to some extent. Oxygen-assisted combustion can also reduce pollutants generated from incomplete combustion.

[0040] The operation of this system is mainly divided into two typical operating conditions based on the power grid load demand: First, low-load operation / energy storage mode When grid demand is low (e.g., at night or during periods of high renewable energy generation), thermal power units reduce the load on their main boilers to near the minimum stable combustion load. At this time, the power output from the generators may exceed the grid dispatch instructions. The system then performs the following operations: The main thermal cycle (boiler-turbine-generator-regenerative system) is maintained at a low load.

[0041] The surplus electricity is directed to the electrolytic cell, which then begins to work, consuming electrical energy and water to produce hydrogen and oxygen.

[0042] The generated hydrogen is purified, compressed, and stored in a hydrogen storage tank, while the oxygen is stored in an oxygen storage tank.

[0043] Under these low-load conditions, to maintain the overall plant thermal efficiency, the induced draft fans and feedwater pumps are mainly or entirely driven by their corresponding small steam turbines. The electric motors are in standby or low-power auxiliary operation.

[0044] The core of this model is the conversion of "electric energy to chemical energy", which realizes the internal absorption and storage of surplus electricity in power plants, avoids energy waste, and reserves the necessary "fuel" and combustion aids for rapid load increase.

[0045] Second, rapid load increase operation / energy release mode When the power grid dispatch requires thermal power units to significantly increase their output within a short period of time, the system activates a rapid response procedure: Hydrogen power generation startup: Hydrogen gas in the storage tank, after pressure regulation, is fed into the fuel cell along with filtered and pressurized air. The fuel cell quickly starts up and undergoes an electrochemical reaction to generate high-grade electrical energy. This electrical energy is directly and rapidly supplied to the induced draft fan motor and the feedwater pump motor via an inverter.

[0046] Oxygen-assisted combustion path startup: After pressure regulation, oxygen in the oxygen storage tank is injected into the boiler furnace through a dedicated pipeline at a controllable flow rate. The addition of high-purity oxygen significantly increases the oxygen concentration and temperature in the combustion zone of the furnace, making fuel combustion more intense and rapid, and allowing the boiler's heat load to increase dramatically.

[0047] Auxiliary machine drive mode switching: The induced draft fan motor and feedwater pump motor, powered by fuel cell electricity, immediately increase their output power. At this time, the auxiliary machine drive mode instantly switches from "gas-driven" to "electric-driven" or "pure electric" mode.

[0048] Induced draft fan: The electric motor drives the induced draft fan to increase its speed rapidly, immediately increasing the boiler's induced draft volume to adapt to the rapidly enhanced combustion caused by oxygen injection, and ensuring that the furnace pressure remains stable within a safe range.

[0049] Feedwater pump: The electric motor drives the feedwater pump to increase its speed rapidly, immediately increasing the water supply to the boiler, so as to absorb the heat that increases sharply due to the enhanced combustion in a timely and sufficient manner, prevent the boiler heating surface from overheating, and accelerate the evaporation process in the water-cooled wall and steam drum, causing the main steam flow and pressure to rise rapidly.

[0050] Waste heat recovery is carried out simultaneously: the waste heat generated by the fuel cell is absorbed by cold water, and the hot water produced is incorporated into the plant's heating network, realizing the cascade utilization of energy.

[0051] The key to this invention lies in the deep coupling and timing coordination of the above three modules: Hydrogen energy serves as a bridge, connecting the "surplus power" and "power deficit" of power plants, thus enabling the spatial and temporal transfer of energy.

[0052] The dual-drive system, powered by steam and electricity, breaks through the thermal inertia bottleneck of traditional thermal systems, enabling the auxiliary machine response speed to be increased from the "minute level" of steam systems to the "second level" of electric systems.

[0053] Oxygen-assisted combustion and electric auxiliary equipment linkage: Oxygen injection provides the ability to "rapidly generate heat", while electric auxiliary equipment provides the ability to "rapidly cooperate with this heat generation" for ventilation and water supply. The two work in sync, powerfully driving the entire boiler-turbine system to quickly establish a new and higher level of energy balance.

[0054] Waste heat recovery improves energy efficiency: turning the "waste heat" of fuel cells into "useful heat" further optimizes the overall energy utilization rate of the plant.

[0055] Example 2 Based on the same inventive concept, this embodiment provides an operation method for a fuel cell-assisted dual-drive thermal power plant rapid load increase system corresponding to the fuel cell-assisted dual-drive thermal power plant rapid load increase system. Since the principle of solving the problem by the operation method in this embodiment is similar to that of the system described in Embodiment 1, the implementation of the method can refer to the implementation of the system, and the repeated parts will not be described again.

[0056] This embodiment provides an operation method for a fuel cell-assisted dual-drive (gasoline and electric) thermal power plant rapid load increase system, specifically including: Step 1: When the system is running at low load, the boiler system maintains the minimum stable combustion load. The fuel burns in the furnace to heat the working fluid, generating high-temperature and high-pressure steam that drives the turbine to rotate and drives the generator to generate electricity. The exhaust steam after doing work enters the condenser and condenses into water. The condensate is heated in stages by the feedwater pump through the low-pressure heater, deaerator and high-pressure heater before flowing back to the boiler, forming a complete thermodynamic cycle. At this time, the induced draft fan and feedwater pump are mainly driven by the corresponding small steam turbines, which are powered by steam extracted from the main steam turbine.

[0057] Step 2: Excess power is transmitted from the generator outlet or the plant power bus to the electrolytic cell. The electrolytic cell consumes electrical energy to electrolyze water, producing hydrogen at the cathode and storing it in a hydrogen storage tank, and producing oxygen at the anode and storing it in an oxygen storage tank. Both the hydrogen storage tank and the oxygen storage tank outlet are equipped with pressure regulators to stabilize the output gas pressure.

[0058] Step 3: When the power grid requires a rapid increase in load, start hydrogen-assisted power generation: After the hydrogen in the hydrogen storage tank is depressurized by the pressure regulator, it is sent to the fuel cell together with the air purified by the air filter and pressurized by the booster. The fuel cell performs an electrochemical reaction to generate direct current. The direct current is converted into alternating current by the inverter and connected to the power supply circuit of the induced draft fan motor and the feedwater pump motor.

[0059] Step 4, synchronously start oxygen combustion: After the oxygen in the oxygen storage tank is depressurized by the pressure regulator, it is injected into the burner area of ​​the boiler furnace at a controllable flow rate through the control valve to increase the oxygen concentration and combustion temperature, thereby enhancing fuel combustion.

[0060] Step 5, Auxiliary machine drive mode switching: After the induced draft fan motor and feedwater pump motor obtain power from the fuel cell, they immediately increase their output power, driving the induced draft fan speed to rapidly increase the induced draft volume to adapt to the increased flue gas volume brought about by enhanced combustion; at the same time, they drive the feedwater pump speed to rapidly increase the water supply volume, timely absorb the sudden increase in heat from the boiler, and promote a rapid increase in the main steam flow and pressure; during this process, the auxiliary machine drive switches from steam-driven to electric-driven.

[0061] Step 6, Waste heat recovery and utilization: The waste heat generated during the fuel cell power generation process is recovered by the integrated heat exchanger. A stream of cold water flows from the plant's domestic water system through the heat exchanger, absorbs the waste heat, is heated into hot water, and then is transported to the plant's hot water pipeline network for heating or domestic hot water, realizing the cascade utilization of energy.

[0062] Step 7: When the thermal power unit is operating under high load and steady-state conditions, the grid demand is high, and the generator output is entirely used to meet the grid power supply. At this time, the water electrolysis energy storage system enters standby and maintenance mode: the control system cuts off the power supply from the generator outlet or the plant power bus to the electrolysis cell, the electrolysis cell stops working, no longer consumes plant power, and ensures that all electrical energy generated by the generator is preferentially transmitted to the grid.

[0063] Step 8: Maintain the pressure of the energy storage tanks and the system's standby status: The hydrogen and oxygen storage tanks maintain their gas storage pressure, and the pressure regulators on the outlet pipelines are in hot standby mode to ensure pressure stability. The control system continuously monitors the tank pressure and gas levels to prepare for potential restarts of energy storage or energy release modes due to load fluctuations. Simultaneously, necessary parameter monitoring and safety inspections are conducted on the electrolysis cell system to ensure it is in optimal standby condition, ready to be quickly restarted and put into energy storage operation upon receiving dispatch instructions or a decrease in system load.

[0064] Step 9: When a power grid dispatch instruction is received requiring the thermal power unit to reduce its output, the control system begins to execute the load reduction procedure. The main control system coordinates the reduction of boiler fuel quantity and main steam flow to ensure that the output power of the turbine-generator unit smoothly decreases to the target low load value.

[0065] Step 10: After the unit power stabilizes at the low load operating point, the system reactivates the water electrolysis energy storage mode: the control system automatically closes the electrical switch connecting the plant power bus to the electrolysis cell, and directs the current surplus power (i.e. the difference between the generator output and the reduced grid demand) to the electrolysis cell.

[0066] Step 11: The electrolysis cell system restarts, consuming surplus electrical energy to perform water electrolysis, continuously producing hydrogen and oxygen. The produced hydrogen is purified, compressed, and stored in a hydrogen storage tank, while the oxygen is stored in an oxygen storage tank, achieving efficient conversion and storage of electrical energy within the plant.

[0067] Step 12: Under this low-load condition, the drive mode of the induced draft fan and the feedwater pump are synchronously switched back to steam drive as the main mode: the corresponding small steam turbine becomes the main power source, while the electric motor reduces its power or switches to standby mode according to system requirements, thereby maximizing the utilization of steam energy and maintaining the overall plant thermal efficiency.

[0068] Step 13: The control system monitors and adjusts the power input of the electrolyzer in real time, so that it dynamically tracks the changes in the surplus power in the plant, ensures the stability of the unit's low-load operation, and reserves sufficient hydrogen and oxygen "fuel" for the next grid load increase demand.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rapid load ramp-up system for thermal power plants with fuel cell-assisted dual-drive steam and electric power, characterized in that, The system includes a thermoelectric conversion module, a hydrogen production and storage module, and a hydrogen-assisted power generation and combustion support module. The thermoelectric conversion module includes a feedwater regeneration system and a flue gas system. The feedwater regeneration system includes a feedwater pump, a small steam turbine for the pump, and a pump motor connected in sequence. The flue gas system includes an induced draft fan, a small steam turbine for the induced draft fan, and an induced draft fan motor connected in sequence. The pump motor and the induced draft fan motor are connected to the hydrogen-assisted power generation and combustion support module. The hydrogen-assisted power generation and combustion module includes a fuel cell and an oxygen reinjection pipeline. The hydrogen pipeline of the fuel cell is connected to the hydrogen production and storage module. The DC output terminal is connected to an inverter, which converts the DC power into AC power and then connects it to the power supply circuit of the water pump motor and the induced draft fan motor. The hydrogen production and storage module is connected to the turbine-generator system via electrical lines and to the thermoelectric conversion module via an oxygen reinjection pipeline.

2. The fuel cell-assisted dual-drive rapid load increase system for thermal power plants as described in claim 1, characterized in that, The thermoelectric conversion module also includes a boiler system and a turbine-generator system, which are connected in sequence. The turbine-generator system includes a main turbine, a generator, and a condenser. The high-temperature and high-pressure steam generated by the boiler system drives the blades of the main turbine to rotate, which in turn drives the coaxial generator to cut magnetic field lines to generate electricity. The exhaust steam after doing work is condensed into water in the condenser and then heated in stages by the feedwater regeneration system before being transported back to the boiler system.

3. The fuel cell-assisted dual-drive rapid load increase system for thermal power plants as described in claim 1, characterized in that, The hydrogen production and storage module includes an electrolyzer, a hydrogen storage tank, and an oxygen storage tank. The input end of the electrolyzer is connected to the power plant generator outlet or the plant power bus via an electrical line. The hydrogen storage tank and the oxygen storage tank are respectively connected to the hydrogen and oxygen outlets of the electrolyzer via pipelines.

4. The fuel cell-assisted dual-drive rapid load increase system for thermal power plants as described in claim 1, characterized in that, Pressure regulators are installed on the outlet pipelines of both the hydrogen storage tank and the oxygen storage tank, and the hydrogen pipeline of the fuel cell is connected to the pressure regulator at the outlet of the hydrogen storage tank.

5. The fuel cell-assisted dual-drive rapid load increase system for thermal power plants as described in claim 1, characterized in that, The hydrogen-assisted power generation and combustion module also includes a booster and an air filter. The air end of the fuel cell is connected to one end of the air filter, and the other end of the air filter is connected to the booster.

6. The fuel cell-assisted dual-drive rapid load increase system for thermal power plants as described in claim 1, characterized in that, The fuel cell integrates a heat exchanger through which cold water flows, absorbing the waste heat generated during the fuel cell's power generation process. The water is then heated into hot water and transported to the plant's hot water network for heating or domestic hot water supply.

7. The fuel cell-assisted dual-drive rapid load increase system for thermal power plants as described in claim 1, characterized in that, The hydrogen storage tank and oxygen storage tank are high-pressure containers.

8. A method for operating a rapid load increase system for a thermal power plant based on a fuel cell-assisted dual-drive system as described in any one of claims 1-7, characterized in that, include: When the power grid is in a period of low load demand, the thermoelectric conversion module is controlled to reduce its output and transmit some of the surplus power generated by the generator to the hydrogen production and storage module. The hydrogen production and storage module uses the surplus power to electrolyze water to produce hydrogen and oxygen. Under this condition, the induced draft fan and the feedwater pump are driven by their corresponding small steam turbines. When the power grid requires a rapid increase in load, the hydrogen-assisted power generation and combustion-supporting module is activated, specifically including: Hydrogen from the hydrogen production and storage module is fed into the fuel cell for an electrochemical reaction to generate electricity, which is then directly supplied to the drive motors of the induced draft fan and the water pump; oxygen is delivered to the thermoelectric conversion module for combustion support. The driving mode of the induced draft fan and the water supply pump is switched from being mainly driven by steam to being mainly driven by electric power supplied by the fuel cell or a pure electric drive mode. The speed of the induced draft fan and the water supply pump is quickly increased by the corresponding electric motor to match the combustion process enhanced by oxygen-assisted combustion.

9. The working method as described in claim 8, characterized in that, It also includes a high-load steady-state operation step: when the thermoelectric conversion module is running under high load steady-state conditions, the power supply to the electrolysis cell is cut off, and the generator output is supplied to the power grid; the hydrogen storage tank and oxygen storage tank maintain gas storage pressure and are in standby mode.

10. The working method as described in claim 8, characterized in that, It also includes a load reduction switching step: when a command to reduce output is received, the conventional power conversion module is controlled to reduce output; after the power stabilizes at a low load value, the surplus power is transmitted to the electrolytic cell for electrolysis to produce hydrogen and oxygen, and at the same time the drive mode of the induced draft fan and the feedwater pump is switched back to be driven by the small steam turbine.

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