A centralized air supply based fuel cell cogeneration system and control method

Abstract

The application provides a fuel cell cogeneration system based on centralized air supply and a control method. The system comprises a fuel cell stack for power generation and heat generation, a heat management subsystem for recovering and distributing heat generated by the fuel cell stack and auxiliary components, the heat management subsystem comprising a main heat exchange loop and an auxiliary heat exchange loop, an air path subsystem for providing filtered, stabilized, preheated and humidified air to the cathode of the fuel cell stack, a hydrogen path subsystem for providing preheated hydrogen to the anode of the stack and circulating unreacted gas, and a tail gas recovery subsystem for condensing and recovering water vapor in the stack tail gas and recovering latent heat thereof, the tail gas recovery subsystem comprising a tail gas collection tank, a steam condensing spiral coil provided on an exhaust path of the tail gas collection tank and a tail gas exhaust port. The technical scheme improves the starting reliability, operation stability and economy of the system under the condition of centralized air supply.

Description

Technical Field

[0001] This application relates to the field of fuel cell technology, and in particular to a fuel cell combined heat and power system and control method based on centralized air supply. Background Technology

[0002] As a highly efficient and clean energy conversion device, fuel cells directly convert the chemical energy of hydrogen and oxygen into electrical energy through an electrochemical reaction, with water and heat as the main byproducts. In stationary power generation applications, fuel cells generate a large amount of high-grade waste heat while generating electricity, and its thermal output is almost equivalent to its electrical power. Therefore, the efficient recovery and utilization of this waste heat to achieve combined heat and power (CHP) is key to significantly improving the overall energy efficiency (up to 80% or more) and operational economy of the system.

[0003] Currently, gas supply solutions for stationary fuel cells are mainly divided into two categories: independent gas supply and centralized gas supply. Independent gas supply solutions equip each fuel cell module with an independent air compressor, a relatively mature technology that allows for independent control of intake parameters. However, the air compressor is one of the main power-consuming components of the system, increasing system complexity, cost, and noise. In contrast, centralized gas supply solutions use one or more large air compressors to supply air to multiple fuel cell modules uniformly, offering significant advantages such as lower initial investment, centralized operation and maintenance, and higher overall energy efficiency potential, making it particularly suitable for distributed energy scenarios such as large parks and building complexes. However, this solution also brings new technical challenges: due to the long-distance transportation and distribution of air, the temperature upon arrival at each fuel cell module is often low, especially in cold seasons or regions. Excessively low inlet air temperatures can lead to a decrease in electrochemical reaction rates, causing difficulties in fuel cell startup, unstable output voltage, reduced efficiency, and even shutdowns due to membrane electrode water management imbalances. Regarding thermal management, existing fuel cell combined heat and power systems typically focus on recovering heat generated by the fuel cell stack and power electronic devices (such as DC-DC converters). However, its design often suffers from the following shortcomings: Incomplete waste heat recovery chain: Insufficient recovery of the large amount of latent heat of water vapor and residual sensible heat contained in the tail gas of electrochemical reaction, often resulting in the emission of tail gas as white smoke, causing waste of energy and water resources. Rigid thermal management loop: Heat recovery in the main loop (stack cooling) and auxiliary loop (equipment cooling) usually adopts series or simple parallel connection, which easily leads to mutual interference between the main and auxiliary loop temperatures, complex temperature control strategies, and difficulty in simultaneously optimizing the stack operating temperature and external heat supply quality. Poor maintenance economy: The key component for maintaining coolant purity—the deionizer—requires system shutdown and partial drainage of pipeline coolant when replaced, causing production interruption and resource waste, reducing system availability and economy. Lack of hydrogen path temperature management: Insufficient attention is paid to the temperature of hydrogen entering the stack. Low-temperature hydrogen entering the stack may exacerbate uneven internal temperature distribution, affecting reaction uniformity and stack life. In addition, in centralized gas supply systems, in order to ensure stable flow in each module, components such as throttle valves and back pressure valves are often installed at the end of the air pipeline, increasing system resistance, control complexity, and cost. Therefore, there is an urgent need for a fuel cell cogeneration solution that can systematically address the comprehensive challenges of intake heating, efficient and flexible waste heat recovery, low-cost maintenance, and high overall economic efficiency under centralized gas supply conditions. Summary of the Invention

[0004] This application provides a fuel cell cogeneration system and control method based on centralized air supply, which at least solves the comprehensive problems faced by fuel cells under centralized air supply mode, such as "low inlet air temperature leading to difficulty in starting, insufficient waste heat recovery from exhaust, rigid thermal management loop, and need for shutdown for critical maintenance", resulting in insufficient system economy and reliability.

[0005] The first aspect of this application provides a fuel cell cogeneration system with centralized air supply, the system comprising:

[0006] Fuel cell stacks are used for power generation and heat production; A thermal management subsystem is used to recover and distribute the heat generated by the fuel cell stack and its accessories. The thermal management subsystem includes: a main heat exchange loop for cooling the fuel cell stack and recovering its high-quality waste heat, the main heat exchange loop being fluidly connected to the fuel cell stack, intercooler, first three-way valve, main loop water pump, second three-way valve, heater, main heat exchanger, and main heat storage tank; and an auxiliary heat exchange loop for cooling the DC / DC converter and recovering its heat, the auxiliary heat exchange loop being fluidly connected to the DC / DC converter, auxiliary heat exchanger, auxiliary water pump, and auxiliary heat storage tank. An air circuit system is used to supply filtered, pressure-stabilized, preheated and humidified air to the cathode of the fuel cell stack. The air circuit system is connected in sequence along the air intake direction to the air inlet, the pressure-stabilized air storage tank, the air filter, the third water inlet of the intercooler, the intercooler, the fourth water inlet of the intercooler, and the humidifier, and is connected to the fuel cell stack. The hydrogen circuit system is used to supply preheated hydrogen to the anode of the fuel cell stack and circulate unreacted gas. The hydrogen circuit system is connected in sequence along the gas inlet, hydrogen preheater, and hydrogen injection device and connected to the anode of the fuel cell stack. The unreacted gas is processed by hydrogen reflux pressurization device and gas-liquid separator. The exhaust gas recovery subsystem is used to condense and recover water vapor in the tailpipe of the fuel cell stack and recover its latent heat. The exhaust gas recovery subsystem includes a tailpipe water collection tank, a steam condensing spiral coil and a tailpipe exhaust port located on its exhaust path.

[0007] Preferably, the main heat exchange circuit includes a deionization filter module for online maintenance. The deionization filter module includes an ionizer and a particulate filter. The deionizer and the particulate filter are connected in series, and the particulate filter is located downstream of the deionizer. The inlet of the deionizer is connected in parallel with a first switching valve and a second switching valve, and its outlet is connected in parallel with a third switching valve and a fourth switching valve. By closing the first and third switching valves and opening the second and fourth switching valves, the deionization filter module is isolated from the main heat exchange circuit for replacement. At the same time, the main heat exchange circuit is kept open through a bypass, thereby avoiding system downtime and coolant waste. A conductivity meter is installed between the second switching valve and the particulate filter.

[0008] Furthermore, the first port of the first three-way valve is connected to the coolant outlet of the fuel cell stack, the second port is connected to the first water inlet of the intercooler, and the third port is connected to the first port of the second three-way valve. The second port of the second three-way valve is connected to the heater inlet, and the third port is connected to the primary side inlet of the main heat exchanger; The inlet of the main loop water pump collects coolant from the primary side outlet of the main heat exchanger and the heater outlet, and its outlet is connected to the coolant inlet of the fuel cell stack. The intercooler is equipped with a second temperature sensor. A third temperature sensor and a fourth temperature sensor are provided between the humidifier and the fuel cell stack; A second water inlet for the intercooler is also provided below the intercooler; A fifth temperature sensor is provided between the fuel cell stack and the hydrogen injection device. A sixth temperature sensor is provided between the fuel cell stack and the gas-water separator. A seventh temperature sensor is installed at the outlet of the hydrogen injection device.

[0009] Furthermore, the air circuit subsystem is provided with an air return pressure stabilization circuit. One end of the air return pressure stabilization circuit is connected between the fourth water port of the intercooler and the intercooler, and the other end is connected back to the pressure stabilization storage tank. An air return valve is provided on the air return pressure stabilization circuit. A flow meter is installed between the air filter and the pressure-stabilizing air storage tank; A main air inlet valve is installed between the pressure-stabilizing gas storage tank and the air inlet.

[0010] Furthermore, the gas side of the hydrogen preheater is connected in series in the pipeline between the hydrogen inlet at the source end and the hydrogen injection device, and is controlled by the first electrically controlled valve, the second electrically controlled valve, and the third electrically controlled valve on the gas side of the hydrogen preheater. The first water-side interface and the second water-side interface of the hydrogen preheater are connected to the main heat exchange circuit or the auxiliary heat exchange circuit of the thermal management subsystem through pipelines. The hydrogen inlet is equipped with an eighth temperature sensor at its input end. The first electrically controlled valve on the gas side of the hydrogen preheater is connected to the gas side interface of the first hydrogen preheater, and the second electrically controlled valve on the gas side of the hydrogen preheater is connected to the gas side interface of the second hydrogen preheater.

[0011] Furthermore, the exhaust water collection tank of the exhaust gas recovery subsystem is provided with an arc-shaped top cover for guiding and condensing the gas-liquid mixture; The exhaust port of the tail drain water tank is connected to the steam condensing spiral coil for secondary condensation of the remaining steam; The liquid outlet of the tail drain water collection tank is connected to the auxiliary heat storage tank or auxiliary heat exchange circuit through a one-way valve. The tailwater collection tank is equipped with a first temperature sensor and a tailwater collection tank heating rod.

[0012] Furthermore, the main heat storage tank and the auxiliary heat storage tank are driven by the secondary side water pump of the main circuit and the secondary side water pump of the auxiliary circuit, respectively, forming an independent cycle with the secondary side of the corresponding main heat exchanger and the auxiliary heat exchanger. The main heat storage tank and the auxiliary heat storage tank are respectively equipped with a main heat storage tank level gauge and an auxiliary heat storage tank level gauge, a main heat storage tank thermometer and an auxiliary heat storage tank thermometer, a main heat storage tank heating rod and an auxiliary heat storage tank heating rod, and a main circuit heating outlet, a main circuit drain outlet, an auxiliary circuit heating outlet and an auxiliary circuit drain outlet controlled by a first solenoid valve, a second solenoid valve, a third solenoid valve and a fourth solenoid valve. Wherein, the first water inlet is connected to the first expansion tank, and the second water inlet is connected to the second expansion tank; A ninth switching valve is provided between the main heat exchanger and the main heat storage tank. A tenth switching valve is provided between the main heat exchanger and the secondary side water pump of the main circuit. An eleventh switching valve is provided between the auxiliary heat exchanger and the auxiliary heat storage tank. A twelfth switching valve is installed between the auxiliary heat exchanger and the secondary side water pump of the auxiliary circuit.

[0013] The second aspect of this application proposes a start-up control method for a fuel cell combined heat and power system based on centralized air supply, applicable to centralized air supply scenarios without independent air compressors. The start-up control method includes: Open the main air inlet valve to supply air to the pressure-stabilizing air tank; Monitor the pressure inside the pressure-stabilized gas storage tank and determine whether it has reached the first pressure threshold; If the first pressure threshold is reached, the air flow rate entering the system is further monitored, and it is determined whether the first flow rate threshold is reached. If the first flow rate threshold is reached, the air temperature after being heated by the intercooler is monitored, and it is determined whether the first temperature threshold has been reached. If the first temperature threshold is not reached, the heater and main circuit water pump of the thermal management subsystem are started, and the first three-way valve is adjusted to allow the coolant to flow through the intercooler to heat the air until the air temperature reaches the first temperature threshold. Determine whether the internal temperature of the fuel cell stack has reached the second temperature threshold. If the internal temperature of the fuel cell stack reaches the second temperature threshold, hydrogen and air are introduced into the fuel cell stack to start its operation.

[0014] Preferably, the method further includes: In the step of determining whether the pressure in the pressure-stabilized gas storage tank has reached the first pressure threshold, if it has not, a gas supply fault check is performed. If the gas supply fails to reach the target after more than the preset number of consecutive checks, the system will be shut down as a gas supply failure.

[0015] A third aspect of this application provides an operation control method for a fuel cell combined heat and power system based on centralized air supply, the operation control method comprising: S10: Intelligent water replenishment strategy: Real-time monitoring of the liquid level in the main and auxiliary heat storage tanks. When the liquid level is lower than the set value, the first solenoid valve, the second solenoid valve, the third solenoid valve, and the fourth solenoid valve are automatically opened to replenish water. S20: Heating and heat dissipation strategy: Based on the user's heat usage instructions and the temperature of the heat storage tank, control the main circuit heating outlet, auxiliary circuit heating outlet, main circuit drain outlet, and auxiliary circuit drain outlet to achieve on-demand heating or prevent overheating; S30: Online maintenance strategy: Monitor conductivity meter readings, and when water quality exceeds the standard, isolate and replace the deion filter module online by controlling the first, second, third, and fourth switching valves without system shutdown; S40: Tailwater recovery strategy: When the liquid level in the tailwater collection tank reaches the preset height, the one-way valve is opened to guide the recovered condensate into the auxiliary circuit for reuse.

[0016] The technical solutions provided by the embodiments of this application bring at least the following beneficial effects: This application proposes a fuel cell combined heat and power (CHP) system and control method based on centralized air supply. The system includes: a fuel cell stack for power generation and heat generation; a thermal management subsystem for recovering and distributing the heat generated by the fuel cell stack and its accessories, the thermal management subsystem including: a main heat exchange loop for cooling the fuel cell stack and recovering its high-quality waste heat, the main heat exchange loop being fluidly connected to the fuel cell stack, intercooler, first three-way valve, main loop water pump, second three-way valve, heater, main heat exchanger, and main heat storage tank; an auxiliary heat exchange loop for cooling the DC / DC converter and recovering its heat, the auxiliary heat exchange loop being fluidly connected to the DC / DC converter, auxiliary heat exchanger, auxiliary water pump, and auxiliary heat storage tank; and an air supply subsystem for supplying air to the fuel cell stack cathode. The system provides filtered, pressurized, preheated, and humidified air. The air path subsystem, along the air intake direction, sequentially connects to the air inlet, pressurized storage tank, air filter, third intercooler inlet, intercooler, fourth intercooler inlet, and humidifier, and is connected to the fuel cell stack. The hydrogen path subsystem, used to supply preheated hydrogen to the stack anode and circulate unreacted gases, is along the air intake direction and sequentially connects to the hydrogen inlet, hydrogen preheater, and hydrogen injection device, and is connected to the fuel cell stack anode. Unreacted gases are processed by a hydrogen reflux pressurization device and a gas-water separator. The exhaust gas recovery subsystem, used to condense and recover water vapor and its latent heat from the stack exhaust, includes an exhaust water collection tank, a steam condensation spiral coil located on its exhaust path, and an exhaust port. The technical solution proposed in this application significantly improves the start-up reliability, operational stability, and overall energy economy of the fuel cell cogeneration system under centralized gas supply conditions.

[0017] Additional aspects and advantages of this application 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 this application. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a block diagram of a fuel cell cogeneration system with centralized air supply according to an embodiment of this application; Figure 2 This is a structural diagram of a deionization filtration module provided according to an embodiment of this application; Figure 3 This is a schematic diagram of the thermal management loop process in a fuel cell combined heat and power system with centralized air supply according to an embodiment of this application; Figure 4 This is a schematic diagram of the air path and hydrogen path in a centralized air-supply fuel cell cogeneration system according to an embodiment of this application; Figure 5 This is a flowchart illustrating a start-up control method for a fuel cell cogeneration system based on centralized air supply, according to an embodiment of this application. Figure 6 This is a flowchart illustrating an operation control method for a fuel cell cogeneration system based on centralized air supply, according to an embodiment of this application. Figure Labels Thermal Management Subsystem 100, Air Circuit Subsystem 200, Hydrogen Circuit Subsystem 300, Main Heat Exchange Circuit 127, Auxiliary Heat Exchange Circuit 128, Exhaust Gas Recovery Subsystem 400, Air Recirculation and Voltage Stabilization Circuit 201, Fuel Cell Stack 1, Intercooler 2, First Three-Way Valve 3, Main Circuit Water Pump 4, Intercooler First Air Port 5, Intercooler Second Air Port 6, Second Three-Way Valve 7, Heater 8, First Switching Valve 9, Second Switching Valve 10, Conductivity Meter 11, Particulate Filter 12, Third Switching Valve 13, Deionizer 14, Fourth Switching Valve 15, First Water Inlet 16, First Expansion Tank 17, Main Heat Exchanger 18, Ninth Switching Valve 19, Tenth Switching Valve 20, DC / D 21. Converter C; 22. Auxiliary water pump; 23. Second water inlet; 24. Second expansion tank; 25. Auxiliary heat exchanger; 26. Eleventh switch valve; 27. Twelfth switch valve; 28. Secondary side water pump of main circuit; 29. ​​Secondary side water pump of auxiliary circuit; 30. Tail exhaust port; 31. Steam condensing spiral coil; 32. Tail exhaust water collection tank; 33. Tail exhaust water collection tank level gauge; 34. First temperature sensor; 35. Water collection tank insulation layer; 36. Tail exhaust water collection tank heating rod; 37. Tail exhaust port; 38. One-way valve; 39. Air inlet; 40. Second temperature sensor; 41. Air filter; 42. Pressure stabilizing air storage tank; 43. Third temperature sensor; 44. Fourth temperature sensor; 45. Humidifier; 46. First water inlet of intercooler. Intercooler second water inlet 47, main heat storage tank 48, main heat storage tank heating rod 49, main heat storage tank level gauge 50, main heat storage tank thermometer 51, auxiliary heat storage tank 52, auxiliary heat storage tank heating rod 53, auxiliary heat storage tank level gauge 54, auxiliary heat storage tank thermometer 55, third water inlet 56, first solenoid valve 57, second solenoid valve 58, third solenoid valve 59, fourth solenoid valve 60, fifth switching valve 61, sixth switching valve 62, seventh switching valve 63, eighth switching valve 64, main circuit heating outlet 65, main circuit drain outlet 66, auxiliary circuit heating outlet 67, auxiliary circuit drain outlet 68, fifth temperature sensor 69, sixth temperature sensor 70, gas-water separator 71, hydrogen return 72. Flow booster device, 73. Hydrogen injection device, 74. Seventh temperature sensor, 75. Hydrogen inlet, 76. Pressure sensor, 77. Arc-shaped top cover, 78. Eighth temperature sensor, 79. Air return valve, 115. Air flow meter, 116. Main air inlet valve, 117. First electrically controlled valve on the gas side of the hydrogen preheater, 118. First interface on the water side of the hydrogen preheater, 119. Second interface on the water side of the hydrogen preheater, 120. Hydrogen preheater, 121. Second electrically controlled valve on the gas side of the hydrogen preheater, 122. Third electrically controlled valve on the gas side of the hydrogen preheater, 123. Ninth temperature sensor, 124. First interface on the gas side of the hydrogen preheater, 125. Second interface on the gas side of the hydrogen preheater, 126. Deionization filter module. Detailed Implementation

[0019] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0020] This application proposes a fuel cell combined heat and power (CHP) system and control method based on centralized air supply. The system includes: a fuel cell stack for power generation and heat generation; a thermal management subsystem for recovering and distributing the heat generated by the fuel cell stack and its accessories, the thermal management subsystem including: a main heat exchange loop for cooling the fuel cell stack and recovering its high-quality waste heat, the main heat exchange loop being fluidly connected to the fuel cell stack, intercooler, first three-way valve, main loop water pump, second three-way valve, heater, main heat exchanger, and main heat storage tank; an auxiliary heat exchange loop for cooling the DC / DC converter and recovering its heat, the auxiliary heat exchange loop being fluidly connected to the DC / DC converter, auxiliary heat exchanger, auxiliary water pump, and auxiliary heat storage tank; and an air supply subsystem for supplying air to the fuel cell stack cathode. The system provides filtered, pressurized, preheated, and humidified air. The air path subsystem, along the air intake direction, sequentially connects to the air inlet, pressurized storage tank, air filter, third intercooler inlet, intercooler, fourth intercooler inlet, and humidifier, and is connected to the fuel cell stack. The hydrogen path subsystem, used to supply preheated hydrogen to the stack anode and circulate unreacted gases, is along the air intake direction and sequentially connects to the hydrogen inlet, hydrogen preheater, and hydrogen injection device, and is connected to the fuel cell stack anode. Unreacted gases are processed by a hydrogen reflux pressurization device and a gas-water separator. The exhaust gas recovery subsystem, used to condense and recover water vapor and its latent heat from the stack exhaust, includes an exhaust water collection tank, a steam condensation spiral coil located on its exhaust path, and an exhaust port. The technical solution proposed in this application significantly improves the start-up reliability, operational stability, and overall energy economy of the fuel cell cogeneration system under centralized gas supply conditions.

[0021] The following description, with reference to the accompanying drawings, illustrates an embodiment of a fuel cell combined heat and power system and control method based on centralized air supply.

[0022] Example 1 Figure 1 This is a structural diagram of a fuel cell cogeneration system with centralized air supply according to an embodiment of this application, as shown below. Figure 1 and Figure 3 As shown, the system includes: Fuel cell stack 1, used for power generation and heat generation; Thermal management subsystem 100 is used to recover and distribute the heat generated by the fuel cell stack 1 and its accessories. The thermal management subsystem includes: The main heat exchange circuit 127 is used to cool the fuel cell stack 1 and recover its high-quality waste heat. The main heat exchange circuit is in fluid connection with the fuel cell stack 1, the intercooler 2, the first three-way valve 3, the main circuit water pump 4, the second three-way valve 7, the heater 8, the main heat exchanger 18 and the main heat storage tank 48. An auxiliary heat exchange circuit 128 is used to cool the DC / DC converter 21 and recover its heat. The auxiliary heat exchange circuit is in fluid connection with the DC / DC converter 21, the auxiliary heat exchanger 25, the auxiliary water pump 22 and the auxiliary heat storage tank 52. An air circuit subsystem 200 is used to supply filtered, pressure-stabilized, preheated, and humidified air to the cathode of the fuel cell stack 1. The air circuit subsystem is connected in sequence along the air intake direction to an air inlet 39, a pressure-stabilized air storage tank 42, an air filter 41, an intercooler first air port 5, an intercooler 2, an intercooler second air port 6, and a humidifier 45, and is connected to the fuel cell stack 1. The hydrogen circuit subsystem 300 is used to supply preheated hydrogen to the anode of the fuel cell stack and circulate unreacted gas. The hydrogen circuit subsystem is connected in sequence along the gas inlet direction to the hydrogen inlet 75, the hydrogen preheater 120, the hydrogen injection device 73 and the anode of the fuel cell stack 1. The unreacted gas is processed by the hydrogen reflux pressurization device 72 and the gas-liquid separator 71. The exhaust gas recovery subsystem 400 is used to condense and recover water vapor in the tailpipe of the fuel cell stack and recover its latent heat. The exhaust gas recovery subsystem includes a tailpipe water collection tank 32, a steam condensing spiral coil 31 and a tailpipe exhaust port 30 located on its exhaust path.

[0023] In the embodiments disclosed herein, such as Figure 2 and Figure 3 As shown, the main heat exchange circuit 127 is equipped with a deionization filter module 126 for online maintenance. The deionization filter module 126 includes an ionizer 14 and a particulate filter 12. The deionizer 14 and the particulate filter 12 are connected in series, and the particulate filter 12 is located downstream of the deionizer 14. The inlet end of the deionizer 14 is connected in parallel with a first switching valve 9 and a second switching valve 10, and its outlet end is connected in parallel with a third switching valve 13 and a fourth switching valve 15. By closing the first switching valve 9 and the third switching valve 13 and opening the second switching valve 10 and the fourth switching valve 15, the deionization filter module 126 is isolated from the main heat exchange circuit 127 for replacement. At the same time, the main heat exchange circuit is kept open through a bypass, thereby avoiding system downtime and coolant waste. A conductivity meter 11 is provided between the second switching valve 10 and the particulate filter 12.

[0024] In the embodiments disclosed herein, such as Figure 4As shown, the first port of the first three-way valve 3 is connected to the coolant outlet of the fuel cell stack 1, the second port is connected to the first water inlet 46 of the intercooler, and the third port is connected to the first port of the second three-way valve 7. The second port of the second three-way valve 7 is connected to the inlet of the heater 8, and the third port is connected to the primary side inlet of the main heat exchanger 18; The inlet of the main circuit water pump 4 collects coolant from the primary side outlet of the main heat exchanger 18 and the outlet of the heater 8, and its outlet is connected to the coolant inlet of the fuel cell stack 1. The intercooler 2 is equipped with a second temperature sensor 40. A third temperature sensor 43 and a fourth temperature sensor 44 are provided between the humidifier 45 and the fuel cell stack 1; A second water inlet 47 for the intercooler is also provided below the intercooler 2; A fifth temperature sensor 69 is provided between the fuel cell stack 1 and the hydrogen injection device 73; A sixth temperature sensor 70 is provided between the fuel cell stack 1 and the gas-water separator 71; A seventh temperature sensor 74 is installed at the outlet of the hydrogen injection device 73.

[0025] Furthermore, such as Figure 4 As shown, the air circuit subsystem is provided with an air return pressure stabilizing circuit 201. One end of the air return pressure stabilizing circuit 201 is connected between the second air port 6 of the intercooler and the intercooler 2, and the other end is connected back to the pressure stabilizing air storage tank 42. An air return valve 79 is provided on the air return pressure stabilizing circuit. An air flow meter 115 is provided between the air filter 41 and the pressure-stabilizing air storage tank 42; An air inlet valve 116 is provided between the pressure-stabilizing gas storage tank 42 and the air inlet 39.

[0026] It should be noted that the pressure-stabilizing gas storage tank 42 includes an eighth temperature sensor 78 and a pressure sensor 76, which are used to monitor the temperature and pressure of the incoming air and also to resist the impact of the incoming air pressure.

[0027] Furthermore, such as Figure 4 As shown, the gas side of the hydrogen preheater 120 is connected in series in the pipeline between the hydrogen inlet 75 at the source end and the hydrogen injection device 73, and is controlled by the first electrically controlled valve 117, the second electrically controlled valve 121, and the third electrically controlled valve 122 on the gas side of the hydrogen preheater. The first water-side interface 118 and the second water-side interface 119 of the hydrogen preheater 120 are connected to the main heat exchange circuit or auxiliary heat exchange circuit of the thermal management subsystem through pipelines. The hydrogen inlet 75 is equipped with a ninth temperature sensor 123 at its input end. The first electrically controlled valve 117 on the gas side of the hydrogen preheater is connected to the first interface 124 on the gas side of the hydrogen preheater, and the second electrically controlled valve 121 on the gas side of the hydrogen preheater is connected to the second interface 125 on the gas side of the hydrogen preheater.

[0028] In the embodiments disclosed herein, such as Figure 3 As shown, the tail gas recovery subsystem has an arc-shaped top cover 77 on the top of the tail gas collection tank 32 for guiding and condensing the gas-liquid mixture; The exhaust port of the tail drain water tank 32 is connected to the steam condensing spiral coil 31 for secondary condensation of the remaining steam; The liquid outlet of the tail drain water collection tank 32 is connected to the auxiliary heat storage tank 52 or the auxiliary heat exchange circuit through a one-way valve 38. The tailwater collection tank 32 is equipped with a first temperature sensor 34 and a tailwater collection tank heating rod 36.

[0029] The tail drain water collection tank 32 is provided with a water collection tank insulation layer 35 on the outside, and a tail drain water collection tank level gauge 33 is installed inside the tail drain water collection tank 32. The tail discharge water collection tank 32 is connected to the tail discharge port 37.

[0030] In the embodiments disclosed herein, such as Figure 3 As shown, the main heat storage tank 48 and the auxiliary heat storage tank 52 are driven by the secondary side water pump 28 of the main circuit and the secondary side water pump 29 of the auxiliary circuit, respectively, and form independent circulation with the secondary side of the corresponding main heat exchanger 18 and the auxiliary heat exchanger 25. The main heat storage tank 48 and the auxiliary heat storage tank 52 are respectively equipped with a main heat storage tank level gauge 50 and an auxiliary heat storage tank level gauge 54, a main heat storage tank thermometer 51 and an auxiliary heat storage tank thermometer 55, a main heat storage tank heating rod 49 and an auxiliary heat storage tank heating rod 53, and a main circuit heating outlet 65, a main circuit drain outlet 66, an auxiliary circuit heating outlet 67 and an auxiliary circuit drain outlet 68 controlled by a first solenoid valve 57, a second solenoid valve 58, a third solenoid valve 59 and a fourth solenoid valve 60. Wherein, the first water inlet 16 is connected to the first expansion tank 17, and the second water inlet 23 is connected to the second expansion tank 24; A ninth switching valve 19 is provided between the main heat exchanger 18 and the main heat storage tank 48; A tenth switching valve 20 is provided between the main heat exchanger 18 and the secondary side water pump 28 of the main circuit; An eleventh switching valve 26 is provided between the auxiliary heat exchanger 25 and the auxiliary heat storage tank 52. A twelfth switching valve 27 is provided between the auxiliary heat exchanger 25 and the secondary side water pump 29 of the auxiliary circuit.

[0031] Specifically, such as Figure 3 As shown, the centralized air supply fuel cell cogeneration system includes: a main heat exchanger 18, an auxiliary heat exchanger 25, a tailpipe water collection tank 32, a main heat storage tank 48 for storing hot water demanded by users, an auxiliary heat storage tank 52, a steam condensing spiral coil 31 on the primary side coolant outlet side of the tailpipe heat exchanger, a first three-way valve 3 and a second three-way valve 7 on the fuel cell stack 1 side, an intercooler 2, a heater 8, etc.

[0032] In this embodiment, the main heat exchanger 8 is used to recover the heat generated by the fuel cell stack 1 and the intercooler 2; the auxiliary heat exchanger 25 is used to recover the heat generated by the DC-DC converter 21; the tail drain water collection tank 32 adopts an arc-shaped top cover to collect condensate, and the tail drain water collection tank 32 is used to recover the coolant discharged from the tail drain outlet 37; the steam condenser spiral coil 31 is installed at the primary side outlet of the tail drain to condense the coolant in the tail drain steam and realize the secondary recovery of the working fluid.

[0033] In this embodiment, the cooling circuit of the main heat exchanger 18 mainly includes key components such as the fuel cell stack 1, intercooler 2, first three-way valve 3, main loop water pump 4, second three-way valve 7, heater 8, conductivity meter 11, particulate filter 12, deionizer 14, main heat exchanger 18, and second solenoid valve 58, as well as all valves, connectors, and sensors not shown. The fuel cell stack 1 and intercooler 2 form a parallel branch 1. The fuel cell stack 1, second three-way valve 7, and heater 8 form a series branch 1. The fuel cell stack 1, second three-way valve 7, and main heat exchanger 18 form a series branch 2. The primary side cooling water inlet of the main heat exchanger 18 is connected to the second three-way valve 7, and the primary side cooling water outlet of the main heat exchanger 18 is connected to the inlet of the main loop water pump 4 and the outlet of the heater 8. The secondary side cooling water outlet of the main heat exchanger 18 is connected to the main heat storage tank 48, and the cooling water outlet of the main heat storage tank 48 is connected to the inlet of the main loop secondary side water pump 28. A second solenoid valve 58 and a third solenoid valve 59 are installed in the flow channel.

[0034] In this embodiment, the cooling circuit of the auxiliary heat exchanger 25 mainly includes key components such as the DC / DC converter 21 to be cooled, the auxiliary heat exchanger 25, and the first solenoid valve 57, as well as all valves, connectors, sensors, etc. not shown. The DC / DC converter 21 and the auxiliary heat exchanger 25 are connected in series (branch 4). The primary side cooling water inlet and outlet of the auxiliary heat exchanger 25 are connected to the water inlet and outlet of the DC / DC converter 21. The secondary side cooling water inlet of the auxiliary heat exchanger 25 is connected to the outlet of the auxiliary water pump 22, and the secondary side cooling water outlet of the auxiliary heat exchanger 25 is connected to the auxiliary heat storage tank 52. The cooling water outlet of the auxiliary heat storage tank 52 is connected to the inlet of the auxiliary water pump 22.

[0035] In this embodiment, the aforementioned tailrace energy recovery process mainly includes key components such as a one-way valve 38, a tailrace water collection tank 32, a water collection tank insulation layer 35, a steam condensing spiral coil 31, and an arc-shaped top cover 77, as well as all valves, connectors, and sensors not shown. The tailrace water collection tank 32 is equipped with a tailrace water level gauge 33 and has an external water collection tank insulation layer 35. A one-way valve 38 is installed at the coolant outlet of the tailrace water collection tank 32. The one-way valve 38 connects to the secondary side coolant inlet of the auxiliary heat exchanger 25. The condensate from the tailrace flows into the secondary side of the auxiliary heat exchanger 25 for reheating, and then flows into the auxiliary heat storage tank 52. The tailrace water collection tank 32 uses an arc-shaped top cover 77. A steam condensing spiral coil 31 is installed on the exhaust pipe of the arc-shaped top cover 77. Non-recoverable working fluids such as hydrogen are discharged through the tailrace secondary exhaust port, i.e., the tailrace exhaust port 30, improving the safety of the device. It should be noted that the placement of the spiral coil in this specification is not limited to horizontal or vertical placement, but is only for illustrative purposes. Any application of the spiral coil concept in this specification is within the scope of protection of this application.

[0036] In the embodiments disclosed herein, such as Figure 4 As shown, the air circuit subsystem 200 includes a pressure-stabilizing air storage tank 42, an air filter 41, and an intercooler 2. The water inlet and outlet of the intercooler are the first water inlet 46 and the second water inlet 47 of the intercooler, and the air outlet and outlet of the intercooler are the first air inlet 5 and the second air inlet 6 of the intercooler, and a humidifier 45. The hydrogen circuit includes a hydrogen injection device 73, a hydrogen reflux pressurization device 72, and a gas-water separator 71, etc.

[0037] In this embodiment, air enters a pressure-stabilized storage tank 42 for storage and pressure stabilization. The pressure-stabilized storage tank 42 includes an eighth temperature sensor 78 and a pressure sensor 76, used to monitor the temperature and pressure of the incoming air and to resist pressure surges. The stabilized air passes through an air filter 41, an intercooler 2, and a humidifier 45 to filter impurities and provide the required temperature and humidity conditions for reactor entry. The inclusion of a recirculation device eliminates the need for a rear-end throttle valve, reducing the number of electronic control components and simplifying the control process. Furthermore, the installation method eliminates the need for corresponding piping structures, providing ease of assembly and maintenance and improving economic efficiency.

[0038] In this embodiment, fuel that meets the fuel-to-fuel-stall quality requirements enters the fuel cell stack 1 through the hydrogen injection device 73. Excess unreacted fuel returns to the hydrogen injection device 73 through the hydrogen reflux booster device 72 to participate in the later stages of the fuel cell stack 1 reaction. The pipeline from the front end of the hydrogen injection device 73 to the source end hydrogen inlet 75 is called the hydrogen inlet pipeline. A hydrogen preheater 120 is installed on this pipeline and is connected to the main pipeline of the fuel cell thermal management system through the first water-side interface 118 and the second water-side interface 119 of the hydrogen preheater.

[0039] It should be noted that the hydrogen injection device 73 and the hydrogen reflux pressurization device 72 in this specification are only for illustrative purposes. Any application that simultaneously utilizes the concepts of the hydrogen injection device 73 and the hydrogen reflux pressurization device 72 in this specification, or applies the concepts of the hydrogen injection device 73 or the hydrogen reflux pressurization device 72 in this specification alone, is within the scope of protection of this application.

[0040] In summary, the fuel cell cogeneration system with centralized air supply proposed in this embodiment significantly improves the start-up reliability, operational stability, and overall energy economy of the fuel cell cogeneration system under centralized air supply conditions.

[0041] Based on the centralized air supply fuel cell cogeneration system proposed in this embodiment, a start-up control method for the fuel cell cogeneration system is also proposed, such as... Figure 5 As shown, the method, applied to centralized air supply scenarios without independent air compressors, includes: Open the main air inlet valve 116 to supply air to the pressure-stabilizing air storage tank 42; Monitor the pressure inside the pressure-stabilized gas storage tank 42 and determine whether it has reached the first pressure threshold (P1). If the first pressure threshold (P1) is reached, the air flow rate entering the system is further monitored, and it is determined whether the first flow rate threshold (m1) is reached. If the first flow rate threshold (m1) is reached, the air temperature after being heated by the intercooler 2 is monitored, and it is determined whether the first temperature threshold (T1) has been reached. If the first temperature threshold (T1) is not reached, the heater 8 and the main circuit water pump 4 of the thermal management subsystem are started, and the first three-way valve 3 is adjusted so that the coolant flows through the intercooler 2 to heat the air until the air temperature reaches the first temperature threshold (T1). Determine whether the internal temperature of fuel cell stack 1 has reached the second temperature threshold (T2). If the internal temperature of the fuel cell stack reaches the second temperature threshold (T2), hydrogen and air are introduced into the fuel cell stack to start its operation.

[0042] It should be noted that the method further includes: In the step of determining whether the pressure in the pressure-stabilized gas storage tank 42 has reached the first pressure threshold (P1), if it has not reached it, a gas supply failure check is performed. If the gas supply fails to reach the target after more than the preset number of consecutive checks, the system will be shut down as a gas supply failure.

[0043] Specifically, in step 80, open the main air intake valve 116.

[0044] Step 81: Close the air return valve 79 on the air return path.

[0045] Step 82: Monitor the air intake pressure sensor 76 in the pressure-stabilized gas storage tank 42.

[0046] Step 83: Determine whether the intake pressure read by the pressure sensor 76 in the pressure stabilizing tank meets the starting pressure P1. Optionally, the target value of the intake starting pressure P1 is set to 1 bar. When the intake pressure < P1, proceed to step 84; when the intake pressure ≥ P1, proceed to step 87.

[0047] Step 84: Check whether the air supply channel is closed, whether the front-end compressor is started, and whether the air intake requirements are met.

[0048] Step 85: Repeat the intake pressure judgment. If the number of judgments is ≥5, execute the command in step 86 automatically; if the number of judgments is <5, return to step 82.

[0049] Step 86: When the number of detections is ≥5, the intake device is determined to be faulty, and the system is shut down for maintenance.

[0050] Step 87: When the intake pressure is ≥ P1, determine the difference between the actual air flow rate read from the air flow meter 115 on the air circuit and the target flow rate m1. Optionally, the target air flow rate m1 is set to 25 kg / h. When the air intake flow rate is ≥ the target flow rate m1, proceed to step 88; when the air intake flow rate is < the target flow rate m1, proceed to step 81.

[0051] Step 88: Monitor the second temperature sensor 40 at the air outlet of the intercooler.

[0052] Step 89: Determine the relative values ​​of the second temperature sensor 40 at the intercooler air outlet and the target value T1 of the inlet air temperature. Optionally, the target value T1 of the inlet air temperature is set to 25°C. If the intercooler air outlet temperature is less than the target value T1 of the inlet air temperature, proceed to step 90; if the intercooler air outlet temperature is greater than or equal to the target value T1 of the inlet air temperature, proceed to step 92.

[0053] Step 90: When the intercooler air outlet temperature is less than the target value T1 of the inlet air temperature, start the small circulation of the cooling system.

[0054] Open the air return valve 79, start the heater 8 and the main circuit water pump 4, control the opening of the first three-way valve 3, so that the coolant flows through the fuel cell stack 1 and the intercooler, and heats the coolant to the start-up temperature.

[0055] Step 91: Adjust the air return valve angle to 79 degrees to ensure that the air temperature at the rear end of the intercooler meets the set requirements.

[0056] Step 92: Determine the relative values ​​of the internal temperature of fuel cell stack 1 and the target start-up temperature T2. Optionally, the target start-up temperature T2 is set to 25°C. If the internal temperature of fuel cell stack 1 is greater than or equal to the set temperature T2, proceed to step 93; if the internal temperature of fuel cell stack 1 is less than the set temperature T2, proceed to step 89.

[0057] Step 93: The fuel cell system enters the normal startup phase.

[0058] Step 94: Introduce hydrogen and air. Once the system meets the operating conditions, the fuel cell begins operation.

[0059] For air supply conditions using centralized large air compressors, this paper presents a method for controlling air intake and temperature rise to achieve rapid startup of the fuel cell stack. Specifically, in the initial state, a certain amount of air is introduced to determine if the air intake equipment or pipeline meets the conditions for stable fuel cell operation. This demonstrates that the application considers system downtime due to equipment failure, improving equipment safety and reliability. After the air intake equipment is fault-free, the paper determines whether the intake air temperature and stack temperature meet the requirements for fuel cell startup and operation. By adjusting the valve angles on the air return pipeline and the three-way valve angles on the cooling circuit, the intercooler and stack temperatures are ensured to be within the optimal temperature range for fuel cell operation. This improves the accuracy of equipment temperature control and ensures the lifespan of the fuel cell stack.

[0060] In summary, the start-up control method for a fuel cell cogeneration system based on centralized air supply proposed in this embodiment significantly improves the start-up reliability, operational stability, and overall energy economy of the fuel cell cogeneration system under centralized air supply conditions.

[0061] Based on the centralized air supply fuel cell cogeneration system proposed in this embodiment, a method for operating and controlling the fuel cell cogeneration system is also proposed, such as... Figure 6 As shown, the method includes: S10: Intelligent water replenishment strategy: Real-time monitoring of the liquid level in the main and auxiliary heat storage tanks. When the liquid level is lower than the set value, the first solenoid valve 57, the second solenoid valve 58, the third solenoid valve 59, and the fourth solenoid valve 60 are automatically opened to replenish water. S20: Heating and heat dissipation strategy: Based on the user's heating instructions and the temperature of the heat storage tank, control the main circuit heating outlet 65, the auxiliary circuit heating outlet 67, the main circuit drain outlet 66, and the auxiliary circuit drain outlet 68 to achieve on-demand heating or prevent overheating. S30: Online maintenance strategy: Monitor the reading of conductivity meter 11. When the water quality exceeds the standard, control the first switch valve 9, the second switch valve 10, the third switch valve 13, and the fourth switch valve 15 to isolate and replace the deion filter module 126 online without system shutdown. S40: Tailwater recovery strategy: When the liquid level in the tailwater collection tank 32 reaches the preset height, the one-way valve 38 is opened to guide the recovered condensate into the auxiliary circuit for reuse.

[0062] Specifically, in step 95, the liquid level reading on the main thermal storage tank level gauge 50 installed in the main thermal storage tank 48 and the liquid level reading on the auxiliary thermal storage tank level gauge 54 installed in the auxiliary thermal storage tank 52 are monitored.

[0063] Step 96: Determine the difference between the auxiliary hot water tank level and the target level L2. Optionally, set the target value L2 of the auxiliary hot water tank level to 10% Aux_LM. If the auxiliary hot water tank level is less than the target level of 10% Aux_LM, proceed to step 98; if the auxiliary hot water tank level is greater than or equal to the target level of 10% Aux_LM, proceed to step 102.

[0064] Step 97: Determine the magnitude of the liquid level in the main storage tank compared to the target liquid level L1. Optionally, set the target liquid level L1 in the main storage tank to 10% Pri_LM. If the liquid level in the main storage tank is less than the target liquid level of 10% Pri_LM, proceed to step 99; if the liquid level in the main storage tank is greater than or equal to the target liquid level of 10% Pri_LM, proceed to step 103.

[0065] Step 98: When the liquid level in the auxiliary hot water tank is less than 10% of the target liquid level in the auxiliary hot water tank (Aux_LM), close the seventh switch valve 63 and the eighth switch valve 64, and open the fourth solenoid valve 60 to replenish the auxiliary water tank.

[0066] Step 99: When the liquid level in the main hot water tank is less than 10% Pri_LM of the target liquid level in the main hot water tank, close the fifth switch valve 61 and the sixth switch valve 62, and open the third solenoid valve 59 to replenish the main water tank.

[0067] Step 100: Determine the difference between the auxiliary hot water tank level and the target level L2. Optionally, set the target value L2 for the auxiliary hot water tank level to 10% Aux_LM. If the auxiliary hot water tank level is ≥ 10% Aux_LM, proceed to step 102; if the auxiliary hot water tank level is < 10% Aux_LM, no operation is performed.

[0068] Step 101: Determine the magnitude of the liquid level in the main storage tank compared to the target liquid level L1. Optionally, set the target liquid level L1 in the main storage tank to 10% Pri_LM. If the liquid level in the main storage tank is ≥ 10% Pri_LM, proceed to step 103; if the liquid level in the main storage tank is < 10% Pri_LM, no operation is performed.

[0069] Step 102: Close the fourth solenoid valve 60.

[0070] Step 103: Close the third solenoid valve 59.

[0071] Step 104: Determine whether the fuel cell cogeneration system has received the start-up command CMD_CHP. Optionally, in the initial state, only two commands can be received: the start-up command CMD_CHP is 1, and the standby command CMD_CHP is 0. When the fuel cell cogeneration system receives command 1, proceed to step 105; when the fuel cell cogeneration system receives command 0, return to step 95.

[0072] Step 105: Determine the difference between the fuel cell stack water temperature and the target value T3. Optionally, the target value T3 for the fuel cell water temperature is set to 20°C. If the fuel cell stack water temperature is ≥ the set target value T3, proceed to step 106; if the fuel cell stack water temperature is < the set target value T3, no operation is performed.

[0073] Step 106: When the fuel cell stack water temperature is ≥ the set target value T3, the system starts up and the heat exchanger unit starts running.

[0074] Step 107: Heating of the primary and secondary sides of the fuel cell primary and secondary circuits.

[0075] During fuel cell operation, the fuel cell stack 1 in the main circuit of the system releases heat. The primary-side coolant transfers the heat generated by the main circuit stack to the secondary side through the main heat exchanger 18, and the heat is stored in the main heat storage tank 48. Similarly, components such as the DC-DC converter in the auxiliary circuit of the system release heat. The primary-side coolant transfers the heat generated by these components to the secondary side through the auxiliary heat exchanger 25, and the heat is stored in the auxiliary heat storage tank 52. Step 108: Determine the difference between the auxiliary water tank temperature and the target value T5. Optionally, the target value T5 for the auxiliary water tank temperature can be set to 60℃. If the auxiliary water tank temperature is greater than or equal to the set target value T5, proceed to step 110; if the auxiliary water tank temperature is less than the set target value T5, return to step 107.

[0076] Step 109: Determine the difference between the main water tank temperature and the target value T4. Optionally, the target value T4 for the main water tank temperature can be set to 60℃. If the main water tank temperature is greater than or equal to the set target value T4, proceed to step 110; if the main water tank temperature is less than the set target value T4, return to step 107.

[0077] Step 110: Determine whether the fuel cell cogeneration system has received the user-side water usage command CMD_Sup. Optionally, the fuel cell cogeneration system can be configured to receive two commands output by the user side: the water usage command CMD_Sup is set to 1, and the standby command CMD_Sup is set to 0. When the fuel cell cogeneration system receives command 1, proceed to step 112; when the fuel cell cogeneration system receives command 0, proceed to step 111.

[0078] Step 111: When the fuel cell cogeneration system receives a water usage command CMD_Sup of 0 from the user side, the sixth switch valve 62 and the eighth switch valve 64 are opened.

[0079] Step 112: When the fuel cell cogeneration system receives a water usage command CMD_Sup of 1 from the user side, the sixth switch valve 62 and the eighth switch valve 64 are closed.

[0080] Step 113: Open the fifth switch valve 61 and the seventh switch valve 63 to output hot water.

[0081] Step 114: Determine the water level in the tank, execute the water replenishment strategy, and return to step 95.

[0082] In summary, the operation control method for a fuel cell cogeneration system based on centralized air supply proposed in this embodiment significantly improves the start-up reliability, operational stability, and overall energy economy of the fuel cell cogeneration system under centralized air supply conditions.

[0083] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0084] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0085] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A fuel cell cogeneration system with centralized air supply, characterized in that, The system includes: Fuel cell stacks are used for power generation and heat production; A thermal management subsystem is used to recover and distribute the heat generated by the fuel cell stack and its accessories. The thermal management subsystem includes: a main heat exchange loop for cooling the fuel cell stack and recovering its high-quality waste heat, the main heat exchange loop being fluidly connected to the fuel cell stack, intercooler, first three-way valve, main loop water pump, second three-way valve, heater, main heat exchanger, and main heat storage tank; and an auxiliary heat exchange loop for cooling the DC / DC converter and recovering its heat, the auxiliary heat exchange loop being fluidly connected to the DC / DC converter, auxiliary heat exchanger, auxiliary water pump, and auxiliary heat storage tank. An air path subsystem is used to supply filtered, pressure-stabilized, preheated, and humidified air to the cathode of the fuel cell stack. The air path subsystem is connected in sequence along the air intake direction to an air inlet, a pressure-stabilized air storage tank, an air filter, a first air port of the intercooler, an intercooler, a second air port of the intercooler, and a humidifier, and is connected to the fuel cell stack. The hydrogen circuit system is used to supply preheated hydrogen to the anode of the fuel cell stack and circulate unreacted gas. The hydrogen circuit system is connected in sequence along the gas inlet, hydrogen preheater, and hydrogen injection device and connected to the anode of the fuel cell stack. The unreacted gas is processed by hydrogen reflux pressurization device and gas-liquid separator. The exhaust gas recovery subsystem is used to condense and recover water vapor in the tailpipe of the fuel cell stack and recover its latent heat. The exhaust gas recovery subsystem includes a tailpipe water collection tank, a steam condensing spiral coil and a tailpipe exhaust port located on its exhaust path.

2. The system as described in claim 1, characterized in that, The main heat exchange circuit is equipped with a deionization filter module for online maintenance. The deionization filter module includes an ionizer and a particulate filter. The deionizer and the particulate filter are connected in series, and the particulate filter is located downstream of the deionizer. The inlet of the deionizer is connected in parallel with a first switching valve and a second switching valve, and its outlet is connected in parallel with a third switching valve and a fourth switching valve. By closing the first and third switching valves and opening the second and fourth switching valves, the deionization filter module is isolated from the main heat exchange circuit for replacement. At the same time, the main heat exchange circuit is kept open through a bypass, thereby avoiding system downtime and coolant waste. A conductivity meter is installed between the second switching valve and the particulate filter.

3. The system as described in claim 2, characterized in that, The first port of the first three-way valve is connected to the coolant inlet of the fuel cell stack, the second port is connected to the first water inlet of the intercooler, and the third port is connected to the first port of the second three-way valve. The second port of the second three-way valve is connected to the heater inlet, and the third port is connected to the primary side inlet of the main heat exchanger; The inlet of the main loop water pump collects coolant from the primary side outlet of the main heat exchanger and the heater outlet, and its outlet is connected to the coolant inlet of the fuel cell stack. The intercooler is equipped with a second temperature sensor. A third temperature sensor and a fourth temperature sensor are provided between the humidifier and the fuel cell stack; A second water inlet for the intercooler is also provided below the intercooler; A fifth temperature sensor is provided between the fuel cell stack and the hydrogen injection device. A sixth temperature sensor is provided between the fuel cell stack and the gas-water separator. A seventh temperature sensor is installed at the outlet of the hydrogen injection device.

4. The system as described in claim 3, characterized in that, The air circuit subsystem is provided with an air return pressure stabilization circuit. One end of the air return pressure stabilization circuit is connected between the fourth water port of the intercooler and the intercooler, and the other end is connected back to the pressure stabilization storage tank. An air return valve is provided on the air return pressure stabilization circuit. A flow meter is installed between the air filter and the pressure-stabilizing air storage tank; A main air inlet valve is installed between the pressure-stabilizing gas storage tank and the air inlet.

5. The system as described in claim 4, characterized in that, The gas side of the hydrogen preheater is connected in series in the pipeline between the hydrogen inlet at the source end and the hydrogen injection device, and is controlled by the first electrically controlled valve, the second electrically controlled valve, and the third electrically controlled valve on the gas side of the hydrogen preheater. The first water-side interface and the second water-side interface of the hydrogen preheater are connected to the main heat exchange circuit or the auxiliary heat exchange circuit of the thermal management subsystem through pipelines. The hydrogen inlet is equipped with a ninth temperature sensor at its input end. The first electrically controlled valve on the gas side of the hydrogen preheater is connected to the gas side interface of the first hydrogen preheater, and the second electrically controlled valve on the gas side of the hydrogen preheater is connected to the gas side interface of the second hydrogen preheater.

6. The system as described in claim 5, characterized in that, The tail gas recovery subsystem has an arc-shaped top cover on the tail gas collection tank for guiding and condensing the gas-liquid mixture. The exhaust port of the tail drain water tank is connected to the steam condensing spiral coil for secondary condensation of the remaining steam; The liquid outlet of the tail drain water collection tank is connected to the auxiliary heat storage tank or auxiliary heat exchange circuit through a one-way valve. The tailwater collection tank is equipped with a first temperature sensor and a tailwater collection tank heating rod.

7. The system as described in claim 6, characterized in that, The main heat storage tank and the auxiliary heat storage tank are driven by the secondary side water pump of the main circuit and the secondary side water pump of the auxiliary circuit, respectively, and form an independent circulation with the secondary side of the corresponding main heat exchanger and the auxiliary heat exchanger. The main heat storage tank and the auxiliary heat storage tank are respectively equipped with a main heat storage tank level gauge and an auxiliary heat storage tank level gauge, a main heat storage tank thermometer and an auxiliary heat storage tank thermometer, a main heat storage tank heating rod and an auxiliary heat storage tank heating rod, and a main circuit heating outlet, a main circuit drain outlet, an auxiliary circuit heating outlet and an auxiliary circuit drain outlet controlled by a first solenoid valve, a second solenoid valve, a third solenoid valve and a fourth solenoid valve. Wherein, the first water inlet is connected to the first expansion tank, and the second water inlet is connected to the second expansion tank; A ninth switching valve is provided between the main heat exchanger and the main heat storage tank. A tenth switching valve is provided between the main heat exchanger and the secondary side water pump of the main circuit. An eleventh switching valve is provided between the auxiliary heat exchanger and the auxiliary heat storage tank. A twelfth switching valve is installed between the auxiliary heat exchanger and the secondary side water pump of the auxiliary circuit.

8. A start-up control method for a fuel cell cogeneration system based on any one of the systems described in claims 1-7, characterized in that, The method, applicable to centralized air supply scenarios without independent air compressors, includes: Open the main air inlet valve to supply air to the pressure-stabilizing air tank; Monitor the pressure inside the pressure-stabilized gas storage tank and determine whether it has reached the first pressure threshold; If the first pressure threshold is reached, the air flow rate entering the system is further monitored, and it is determined whether the first flow rate threshold is reached. If the first flow rate threshold is reached, the air temperature after being heated by the intercooler is monitored, and it is determined whether the first temperature threshold has been reached. If the first temperature threshold is not reached, the heater and main circuit water pump of the thermal management subsystem are started, and the first three-way valve is adjusted to allow the coolant to flow through the intercooler to heat the air until the air temperature reaches the first temperature threshold. Determine whether the internal temperature of the fuel cell stack has reached the second temperature threshold. If the internal temperature of the fuel cell stack reaches the second temperature threshold, hydrogen and air are introduced into the fuel cell stack to start its operation.

9. The start-up control method as described in claim 8, characterized in that, The method further includes: In the step of determining whether the pressure in the pressure-stabilized gas storage tank has reached the first pressure threshold, if it has not, a gas supply fault check is performed. If the gas supply fails to reach the target after more than the preset number of consecutive checks, the system will be shut down as a gas supply failure.

10. A method for operating and controlling a fuel cell cogeneration system based on any one of the systems described in claims 1-7, characterized in that, The method includes: S10: Intelligent water replenishment strategy: Real-time monitoring of the liquid level in the main and auxiliary heat storage tanks. When the liquid level is lower than the set value, the first solenoid valve, the second solenoid valve, the third solenoid valve, and the fourth solenoid valve are automatically opened to replenish water. S20: Heating and heat dissipation strategy: Based on the user's heat usage instructions and the temperature of the heat storage tank, control the main circuit heating outlet, auxiliary circuit heating outlet, main circuit drain outlet, and auxiliary circuit drain outlet to achieve on-demand heating or prevent overheating; S30: Online maintenance strategy: Monitor conductivity meter readings, and when water quality exceeds the standard, isolate and replace the deion filter module online by controlling the first, second, third, and fourth switching valves without system shutdown; S40: Tailwater recovery strategy: When the liquid level in the tailwater collection tank reaches the preset height, the one-way valve is opened to guide the recovered condensate into the auxiliary circuit for reuse.

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