A multi-cogeneration system and method integrating electricity, heat, cold and fresh water

Abstract

This invention belongs to the field of proton exchange membrane fuel cell technology, specifically relating to a combined power supply system and method integrating electricity, heat, cooling, and desalination. It includes a proton exchange membrane fuel cell power generation system, a micro gas turbine power generation system, a micro steam turbine power generation system, a membrane permeate distillation desalination system, and a regional cooling and heating subsystem connected by pipes and valves. The proton exchange membrane fuel cell power generation system is connected to the micro gas turbine power generation system; the micro gas turbine power generation system is connected to the micro steam turbine power generation system; the micro steam turbine power generation system is connected to the membrane permeate distillation desalination subsystem; and the membrane permeate distillation desalination subsystem is connected to both the regional cooling and heating subsystem and the proton exchange membrane fuel cell power generation system.

Description

Technical Field

[0001] This invention belongs to the field of proton exchange membrane fuel cell technology, specifically relating to a combined power supply system and method that integrates electricity, heat, cooling, and fresh water. 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 the rapid development of society and the advancement of science and technology, the increased use of traditional fossil fuels has led to a sharp rise in carbon emissions. There is an urgent need for an energy system that produces fuels that are virtually pollution-free and can be produced domestically to replace the traditional energy system in daily life.

[0004] Proton exchange membrane fuel cells (PEMFCs) are devices that directly convert the chemical energy of hydrogen into electrical energy. Due to their high energy conversion efficiency, high power density, and environmental friendliness, they effectively compensate for the drawbacks of frequent use of traditional fossil fuels. In recent years, with the rapid development of the hydrogen energy industry, PEMFCs have been increasingly widely used in distributed power generation, backup power supplies, and transportation.

[0005] Besides the inherent drawbacks of using traditional fossil fuels, traditional centralized energy systems also suffer from poor flexibility, low overall system efficiency, and poor safety and reliability. Traditional thermal power plants typically have an overall energy utilization efficiency of only 35%-45%, with a large amount of waste heat being released into the environment, resulting in energy waste. Distributed energy systems, based on the core theory of energy cascade utilization, arrange different subsystems according to different energy grades to achieve full utilization of energy and thus improve the overall energy utilization efficiency of the system.

[0006] In the operation of PEMFCs, there is a phenomenon of incomplete fuel utilization, meaning that unreacted hydrogen exists at the anode of the PEMFC, and the gas at the anode and cathode outlets of the PEMFC contains a certain amount of usable low-temperature waste heat. Treating this unreacted hydrogen and low-temperature waste heat is an important factor in improving the overall energy efficiency of PEMFCs. By combining PEMFCs with distributed energy systems, a combined cooling, heating, and power (CCHP) system based on PEMFCs can be designed. This system can not only fully utilize the unreacted hydrogen and low-temperature waste heat at the anode and cathode outlets of the PEMFC, but also provide additional cooling, heating, and freshwater products to the distributed energy system, meeting more diverse user needs.

[0007] According to the inventors, existing PEMFC-based combined heat and power systems have the following shortcomings: the utilization of unreacted hydrogen at the PEMFC anode is relatively simple, mostly relying on direct emission or simple combustion, failing to fully recover its high-grade heat energy; the utilization efficiency of waste heat from PEMFC cooling water (60-80℃) is low, making it difficult to use it for seawater desalination or refrigeration processes requiring higher temperatures; there is a lack of design for the cascade utilization of flue gas waste heat, especially failing to effectively utilize low-temperature flue gas (80-150℃) for membrane distillation desalination and absorption refrigeration; and the high integration of "electricity-heat-cooling-desalination" quadruple power supply has not been achieved, with insufficient thermal coupling and material circulation optimization between subsystems, and the overall energy utilization efficiency of the system needs further improvement. Summary of the Invention

[0008] To address the aforementioned issues, this invention proposes a combined power generation system and method integrating electricity, heat, cooling, and freshwater. Hydrogen is introduced into a proton exchange membrane fuel cell to generate electricity through a reaction. Based on the core principle of "energy cascade utilization" in distributed energy, the exhaust gas and low-temperature waste heat of the proton exchange membrane fuel cell are rationally recovered and utilized, enabling the resulting combined power generation system to simultaneously meet the diverse needs of users for power generation, freshwater production, cooling, and heating.

[0009] According to some embodiments, the first aspect of the present invention provides a combined power supply system integrating electricity, heat, cooling, and fresh water, employing the following technical solution: A combined power supply system integrating electricity, heat, cooling, and freshwater includes a proton exchange membrane fuel cell power generation system, a micro gas turbine power generation system, a micro steam turbine power generation system, a membrane permeate distillation freshwater production subsystem, and a regional cooling and heating subsystem connected by pipes and valves. The proton exchange membrane fuel cell power generation system is connected to the micro gas turbine power generation system; the micro gas turbine power generation system is connected to the micro steam turbine power generation system; the micro steam turbine power generation system is connected to the membrane permeate distillation freshwater production subsystem; and the membrane permeate distillation freshwater production subsystem is connected to both the regional cooling and heating subsystem and the proton exchange membrane fuel cell power generation system.

[0010] As a further technical limitation, the proton exchange membrane fuel cell power generation system includes a hydrogen storage tank, a first hydrogen compressor, a hydrogen humidifier, a hydrogen preheater, a first air compressor, an air humidifier, an air preheater, and a proton exchange membrane fuel cell; wherein, the first air compressor is connected to the outside, the air compressor is connected to the air humidifier, the air humidifier is connected to the air preheater, and the air preheater is connected to the cathode of the proton exchange membrane fuel cell; the hydrogen storage tank is used to store hydrogen fuel, the first hydrogen compressor is connected to the hydrogen storage tank, the hydrogen humidifier is connected to the first hydrogen compressor, the hydrogen preheater is connected to the hydrogen humidifier, and the hydrogen preheater is connected to the anode of the proton exchange membrane fuel cell; the air humidifier is connected to the hydrogen humidifier.

[0011] Furthermore, the membrane perdistillation desalination subsystem includes a first water pump, a second waste heat boiler, a membrane perdistillation assembly, a first preheater, a seawater pump, a seawater storage tank, a seawater feed pump, a desalination storage tank, and a second water pump; wherein, the first hot-end inlet of the second waste heat boiler is connected to the air preheater, the second hot-end inlet of the second waste heat boiler is connected to the first waste heat boiler, and the first hot-end outlet of the second waste heat boiler is connected to the cooling water inlet of the proton exchange membrane fuel cell; The cold end inlet of the second waste heat boiler is connected to the outlet of the seawater storage tank, the cold end outlet of the second waste heat boiler is connected to the seawater side inlet of the membrane perdistillation assembly, the seawater side outlet of the membrane perdistillation assembly is connected to the hot end inlet of the first preheater, the hot end outlet of the first preheater is connected to the seawater pump, the seawater pump is connected to the first inlet of the seawater storage tank, and the seawater feed pump is connected to the second inlet of the seawater storage tank. The first outlet of the freshwater storage tank is connected to the cold end inlet of the first preheater, the cold end outlet of the first preheater is connected to the freshwater side inlet of the membrane permeation distillation assembly, the freshwater side outlet of the membrane permeation distillation assembly is connected to the second water pump, the second water pump is connected to the first inlet of the freshwater storage tank, the second outlet of the freshwater storage tank is connected to the first water pump, and the first water pump is connected to the air humidifier.

[0012] Furthermore, the regional cooling and heating subsystem includes a steam generator, a second condenser, a first pressure reducing valve, an evaporator, an absorber, a second pressure reducing valve, a circulating pump, a heat exchanger, and a second feedwater pump; wherein, the first inlet of the steam generator is connected to the second outlet of the hot end of the second waste heat boiler, the first outlet of the steam generator is connected to the hot end inlet of the second condenser, the hot end outlet of the second condenser is connected to the first pressure reducing valve, the first pressure reducing valve is connected to the first inlet of the evaporator, the first outlet of the evaporator is connected to the first inlet of the absorber, the outlet of the absorber is connected to the circulating pump, and the circulating pump is connected to the second inlet of the steam generator; The second outlet of the steam generator is connected to the second pressure reducing valve, and the second pressure reducing valve is connected to the second inlet of the absorber; The third outlet of the steam generator is connected to the hot end inlet of the heat exchanger, and the flue gas is discharged to the atmosphere at the hot end outlet of the heat exchanger. The second water pump is connected to the cold end inlet of the heat exchanger, and the hot water flows to the user at the cold end outlet of the heat exchanger.

[0013] As a further technical limitation, the micro gas turbine power generation system includes a second hydrogen compressor, an afterburner, a second air compressor, an intercooler, a third air compressor, and a micro gas turbine; wherein, the second hydrogen compressor is connected to the anode of the proton exchange membrane fuel cell, the second air compressor is connected to the cathode of the proton exchange membrane fuel cell, the intercooler is connected to the second air compressor, the third air compressor is connected to the intercooler, the afterburner is connected to the third air compressor and the second hydrogen compressor, and the afterburner is connected to the micro gas turbine.

[0014] As a further technical limitation, the micro steam turbine power generation system includes a first waste heat boiler, a micro steam turbine, a first condenser, a condensate pump, a regenerator, and a first feedwater pump; wherein, the first waste heat boiler is connected to the micro gas turbine, the micro steam turbine is connected to the hot end inlet of the first condenser, the condensate pump is connected to the hot end outlet of the first condenser, the condensate pump is connected to the second inlet of the regenerator, the micro steam turbine is connected to the first inlet of the regenerator, and the first feedwater pump is connected to the cold end inlet of the first condenser.

[0015] According to some embodiments, the second aspect of the present invention provides a multi-generation system integrating electricity, heat, cooling, and freshwater, which adopts the multi-generation system integrating electricity, heat, cooling, and freshwater provided in the first aspect, and employs the following technical solution: A multi-generation system integrating electricity, heat, cooling, and freshwater supply includes: Based on the proton exchange membrane fuel cell power generation system, hydrogen and air enter the high-temperature proton exchange membrane fuel cell after being preheated, humidified and pressurized in sequence, converting chemical energy into electrical energy. The remaining hydrogen at the anode of the proton exchange membrane fuel cell and the tail gas at the cathode enter the micro gas turbine power generation system together. Hydrogen and air are pressurized and then enter the combustion chamber to burn and produce high-temperature flue gas. The generated high-temperature flue gas drives the gas turbine to rotate and do work. After rotating and doing work, the high-temperature flue gas is transformed into medium-temperature flue gas and then enters the micro steam turbine generator system. The waste heat boiler is heated by medium-temperature flue gas, causing the water in it to evaporate. The evaporated water vapor enters the steam turbine, drives the steam turbine to rotate and do work, and then flows out from the outlet. It then enters the condenser and turns into liquid water, which flows into the regenerator. Some steam is separated from the steam turbine and flows into the regenerator to preheat the condensate. The preheated water then enters the next cycle. The desalination subsystem via membrane permeate distillation heats seawater together with cooling water from the proton exchange membrane fuel cell and low-temperature flue gas from the first waste heat boiler. The heated seawater and preheated desalination water then enter the membrane distillation module to produce new desalination water. The desalination water and seawater return to their respective storage tanks, while the cooling water flows into the proton exchange membrane fuel cell for the next round of cooling. In the regional cooling and heating subsystem, the steam generator for low-temperature flue gas heating absorption refrigeration from the second waste heat boiler separates water vapor from the lithium bromide solution. After condensation and evaporation, the refrigeration is completed. The low-temperature flue gas enters the heat exchanger to provide heat energy to the liquid water and is then discharged into the atmosphere. The liquid water, after absorbing heat, can be used to heat users.

[0016] As a further technical limitation, the hydrogen in the hydrogen storage tank is injected into the first hydrogen compressor for pressurization, flows into the hydrogen humidifier for humidification, and flows into the hydrogen preheater for preheating; at the same time, air flows into the first air compressor from the outside for pressurization, passes through the air humidifier for humidification, and flows into the air preheater for preheating, and together with the pressurized, humidified, and preheated hydrogen, flows into the proton exchange membrane fuel cell to carry out an electrochemical reaction to generate electricity; The residual hydrogen at the anode outlet of the proton exchange membrane fuel cell enters the second hydrogen compressor for pressurization. Simultaneously, the cathode exhaust gas of the proton exchange membrane fuel cell flows into the second air compressor for initial pressurization. The cathode exhaust gas then enters the intercooler for cooling and continues to flow into the third air compressor for a second pressurization to reach the rated pressure. After pressurization, the hydrogen and cathode exhaust gas enter the afterburner and mix and burn to produce high-temperature flue gas. The high-temperature flue gas then flows out from the outlet and enters the micro gas turbine to drive the gas turbine to rotate and do work. At the same time, the flue gas flows out from the outlet of the micro gas turbine and transforms into medium-temperature flue gas to provide heat energy for subsequent subsystems.

[0017] As a further technical limitation, the medium-temperature flue gas flowing out of the micro gas turbine enters the first waste heat boiler to heat water and generate steam. The steam enters the micro steam turbine to drive the steam turbine to rotate and do work. The steam after doing work enters the first condenser, while the first feedwater pump draws liquid water from the outside to absorb the heat of the steam and condense the steam. The condensate is transported to the regenerator by the condensate pump. Some steam is drawn from the steam turbine and transported to the regenerator to preheat the liquid water. The preheated liquid water re-enters the waste heat boiler to participate in the next cycle. In a proton exchange membrane fuel cell, cooling water, after preheating hydrogen and air, enters a second waste heat boiler along with low-temperature flue gas from the hot end outlet of the first waste heat boiler to heat seawater. The seawater is supplied from a seawater storage tank; a seawater feed pump supplies seawater to the storage tank. The seawater is heated to a rated temperature in the second waste heat boiler and flows out into the membrane perdistillation module. Freshwater under ambient conditions flows from a freshwater storage tank, is preheated by a first preheater, and then enters the membrane perdistillation module. Inside the membrane perdistillation module, the seawater side has a higher temperature, and some water separates from the seawater as steam. The water is separated from the oxygen supply and, under the pressure difference caused by the temperature difference on both sides, passes through a porous membrane into the freshwater side. Simultaneously, under the condensation effect of the lower-temperature freshwater side, it transforms into liquid water and flows out of the membrane perdistillation module along with the original freshwater. Then, it is transported back to the freshwater storage tank by the second water pump. At the same time, the waste liquid from the seawater desalination process enters the first preheater to preheat the freshwater that is about to enter the membrane perdistillation module, and is then transported to the seawater storage tank by the seawater pump. Meanwhile, the water required for humidifying the air and hydrogen in the proton exchange membrane fuel cell power generation system is transported from the freshwater storage tank by the first water pump.

[0018] As a further technical limitation, the low-temperature flue gas flowing out of the second waste heat boiler enters the steam generator, heats the lithium bromide solution to separate water vapor, and then enters the second condenser to condense into liquid water. The liquid water flows out of the second condenser and enters the first pressure reducing valve to keep the liquid water in a low-pressure state. The water in the low-pressure state enters the evaporator. Due to the low pressure of the water, it can absorb heat from the low-temperature working fluid and evaporate to form water vapor. Meanwhile, the chilled water on the other side of the evaporator releases heat to achieve the purpose of refrigeration. The water vapor enters the absorber. The lithium bromide concentrated solution, which has lost some water, passes through the second pressure reducing valve and enters the absorber to absorb the water vapor. The heat generated in the process is absorbed and carried away by the cooling water. The mixed lithium bromide solution then re-enters the steam generator under the action of the circulating pump for the next round of refrigeration. The low-temperature flue gas flows out of the steam generator and enters the heat exchanger. The second feed water pump delivers liquid water to the heat exchanger to exchange heat with the low-temperature flue gas to produce hot water for users. Finally, the flue gas is discharged into the atmosphere.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention highly integrates subsystems such as proton exchange membrane fuel cell, gas turbine, steam turbine, membrane distillation for freshwater production, and absorption refrigeration to construct a "cooling-heating-water-electricity" combined cooling, heating, water and electricity system. It not only realizes the cascade utilization of energy, but also significantly improves the overall energy utilization efficiency and system flexibility by optimizing the thermodynamic coupling and material circulation between subsystems.

[0020] This invention adds an afterburner at the PEMFC outlet to perform secondary combustion of unreacted fuel, generating high-grade heat energy to drive a gas turbine and a steam turbine to generate electricity. This achieves deep energy recovery from fuel cell exhaust gas and effectively solves the problem of low exhaust gas utilization rate in traditional PEMFC systems.

[0021] This invention uses hydrogen as the primary fuel, and the PEMFC power generation process produces only water vapor. Combined with complete combustion and exhaust gas treatment in the afterburner, the system achieves near-zero carbon emissions. When integrated with a carbon capture and utilization device, the system structure possesses excellent renewable energy integration capabilities, allowing it to be coupled with clean energy sources such as solar and wind power, further increasing the system's green energy proportion and adapting to the needs of future energy structure transformation. Attached Figure Description

[0022] The accompanying drawings, which form part of this embodiment, are used to provide a further understanding of this embodiment. The illustrative embodiments and their descriptions are used to explain this embodiment and do not constitute an improper limitation of this embodiment.

[0023] Figure 1 This is a schematic diagram of a multi-generation system integrating electricity, heat, cooling, and fresh water according to Embodiment 1 of the present invention; The components include: 1. Hydrogen storage tank; 2. First hydrogen compressor; 3. Hydrogen humidifier; 4. Hydrogen preheater; 5. First air compressor; 6. Air humidifier; 7. Air preheater; 8. Proton exchange membrane fuel cell; 9. Second hydrogen compressor; 10. Afterburner; 11. Second air compressor; 12. Intercooler; 13. Third air compressor; 14. Micro gas turbine; 15. First waste heat boiler; 16. Micro steam turbine; 17. First condenser; 18. Condensate pump. ; 19. Regenerator; 20. First feedwater pump; 21. First water pump; 22. Second waste heat boiler; 23. Membrane permeate distillation unit; 24. First preheater; 25. Seawater pump; 26. Seawater storage tank; 27. Seawater feedwater pump; 28. Freshwater storage tank; 29. ​​Second water pump; 30. Steam generator; 31. Second condenser; 32. First pressure reducing valve; 33. Evaporator; 34. Absorber; 35. Second pressure reducing valve; 36. Circulation pump; 37. Heat exchanger; 38. Second feedwater pump. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration 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.

[0026] 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.

[0027] In this invention, terms such as "upper," "lower," "left," "right," "front," "back," "vertical," "horizontal," "side," and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only to facilitate the description of the structural relationships of the various components or elements of this invention and do not specifically refer to any component or element in this invention. They should not be construed as limiting the invention.

[0028] In this invention, terms such as "fixed connection," "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.

[0029] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0030] Example 1 Embodiment 1 of the present invention introduces a multi-generation system that integrates electricity, heat, cooling and fresh water.

[0031] like Figure 1 The system shown is a combined power supply system integrating electricity, heat, cooling, and fresh water, including a proton exchange membrane fuel cell power generation system, a micro gas turbine power generation system, a micro steam turbine power generation system, a membrane permeate distillation fresh water production subsystem, and a regional cooling and heating subsystem.

[0032] As one or more embodiments, the proton exchange membrane fuel cell power generation system includes a hydrogen storage tank 1, a first hydrogen compressor 2, a hydrogen humidifier 3, a hydrogen preheater 4, a first air compressor 5, an air humidifier 6, an air preheater 7, and a proton exchange membrane fuel cell 8.

[0033] The first air compressor 5 introduces air from the outside. The air compressor 5 is connected to the air humidifier 6, the air humidifier 6 is connected to the air preheater 7, and the air preheater 7 is connected to the cathode inlet of the proton exchange membrane fuel cell 8. The air enters the cathode of the proton exchange membrane fuel cell 8 after being pressurized, humidified, and preheated in sequence.

[0034] In this embodiment, the hydrogen storage tank 1 stores hydrogen as fuel. The first hydrogen compressor 2 is connected to the hydrogen storage tank 1, the hydrogen humidifier 3 is connected to the first hydrogen compressor 2, the hydrogen preheater 4 is connected to the hydrogen humidifier 3, and the hydrogen preheater 4 is connected to the anode inlet of the proton exchange membrane fuel cell 8. The hydrogen enters the anode of the proton exchange membrane fuel cell 8 after being pressurized, humidified, and preheated in sequence. The air humidifier 6 is connected to the hydrogen humidifier 3 to achieve a balance of humidification water.

[0035] In this embodiment, the proton exchange membrane fuel cell 8 is a high-temperature proton exchange membrane fuel cell with an operating temperature of 60-80℃ and an operating pressure of 0.2-0.5MPa. The fuel cell directly converts the chemical energy of hydrogen and air into electrical energy. The generated direct current is converted into alternating current by an inverter and then supplied to the user. The heat generated by the fuel cell reaction is carried away by cooling water at a temperature of approximately 70-90℃, which is used for preheating of subsequent subsystems and seawater desalination.

[0036] As one or more embodiments, the micro gas turbine power generation system includes a second hydrogen compressor 9, an afterburner 10, a second air compressor 11, an intercooler 12, a third air compressor 13, and a micro gas turbine 14.

[0037] The second hydrogen compressor 9 is connected to the anode outlet of the proton exchange membrane fuel cell 8 and is used to pressurize the unreacted hydrogen at the anode to 1.0-2.0 MPa. The second air compressor 11 is connected to the cathode outlet of the proton exchange membrane fuel cell 8 and is used to pressurize the cathode exhaust gas for the first time. The intercooler 12 is connected to the second air compressor 11 and is used to cool the pressurized cathode exhaust gas. The third air compressor 13 is connected to the intercooler 12 and is used to pressurize the cooled cathode exhaust gas for the second time to 1.0-2.0 MPa. The afterburner 10 is connected to the third air compressor 13 and the second hydrogen compressor 9 and is used to mix and burn the pressurized hydrogen and cathode exhaust gas. The afterburner 10 is connected to the micro gas turbine 14 and the generated high-temperature flue gas enters the micro gas turbine 14 to do work.

[0038] In this embodiment, the combustion temperature in the rear combustion chamber 10 can reach 800-1200℃. The high-temperature flue gas generated drives the gas turbine of the micro gas turbine 14 to rotate and do work, driving the generator to generate electricity. After doing work, the flue gas temperature drops to 400-600℃ and enters the next subsystem as medium-temperature flue gas.

[0039] As one or more embodiments, the micro steam turbine power generation system includes a first waste heat boiler 15, a micro steam turbine 16, a first condenser 17, a condensate pump 18, a regenerator 19, and a first feedwater pump 20.

[0040] The first waste heat boiler 15 is connected to the micro gas turbine 14 to recover heat from the medium-temperature flue gas and generate steam. The first waste heat boiler 15 is connected to the micro steam turbine 16, and the generated steam enters the micro steam turbine 16 to do work. The micro steam turbine 16 is connected to the hot end inlet of the first condenser 17, and the exhaust steam after doing work enters the first condenser 17 for condensation. The condensate pump 18 is connected to the hot end outlet of the first condenser 17 to pressurize and transport the condensate. The condensate pump 18 is connected to the second inlet of the regenerator 19, and the micro steam turbine 16 is connected to the first inlet of the regenerator 19. The steam extracted from the middle of the micro steam turbine 16 is used to preheat the condensate. The first feedwater pump 20 is connected to the cold end inlet of the first condenser 17 to provide cooling water to the condenser.

[0041] In this embodiment, medium-temperature flue gas (400-600℃) enters the first waste heat boiler 15, heats water to generate steam at 300-400℃, and the steam drives the steam turbine of the micro steam turbine 16 to rotate and do work, driving the generator to generate electricity; the exhaust steam (about 100-150℃) after doing work enters the first condenser 17 and is condensed into liquid water. The condensate is preheated by the regenerator 19 and then returned to the first waste heat boiler 15 to form a cycle; the flue gas temperature at the outlet of the first waste heat boiler 15 drops to 80-150℃ and enters the next subsystem as low-temperature flue gas.

[0042] As one or more embodiments, the membrane permeation distillation desalination subsystem includes a first water pump 21, a second waste heat boiler 22, a membrane permeation distillation module 23, a first preheater 24, a seawater pump 25, a seawater storage tank 26, a seawater feed pump 27, a desalination storage tank 28, and a second water pump 29.

[0043] The first inlet of the hot end of the second waste heat boiler 22 is connected to the air preheater 7, receiving cooling water (70-90℃) from the proton exchange membrane fuel cell 8; the second inlet of the hot end of the second waste heat boiler 22 is connected to the first waste heat boiler 15, receiving low-temperature flue gas (80-150℃) from the first waste heat boiler 15; the first outlet of the hot end of the second waste heat boiler 22 is connected to the cooling water inlet of the proton exchange membrane fuel cell 8, and the cooling water returns to the fuel cell to complete the cooling cycle.

[0044] The cold end inlet of the second waste heat boiler 22 is connected to the outlet of the seawater storage tank 26 to receive seawater to be treated; the cold end outlet of the second waste heat boiler 22 is connected to the seawater side inlet of the membrane perdistillation unit 23 to send seawater heated to 60-80℃ into the membrane perdistillation unit 23; the seawater side outlet of the membrane perdistillation unit 23 is connected to the hot end inlet of the first preheater 24, where the concentrated brine after seawater desalination is used to preheat fresh water; the hot end outlet of the first preheater 24 is connected to the seawater pump 25, which is connected to the first inlet of the seawater storage tank 26, where the concentrated brine is returned to the seawater storage tank 26; and the seawater feed pump 27 is connected to the second inlet of the seawater storage tank 26 to replenish fresh seawater.

[0045] The first outlet of the freshwater storage tank 28 is connected to the cold end inlet of the first preheater 24, and the freshwater enters the membrane perdistillation module 23 after preheating. The cold end outlet of the first preheater 24 is connected to the freshwater side inlet of the membrane perdistillation module 23. The freshwater side outlet of the membrane perdistillation module 23 is connected to the second water pump 29, and the second water pump 29 is connected to the first inlet of the freshwater storage tank 28, so that the newly generated freshwater returns to the freshwater storage tank 28. The second outlet of the freshwater storage tank 28 is connected to the first water pump 21, and the first water pump 21 is connected to the air humidifier 6, which is used to provide humidification water to the fuel cell power generation system.

[0046] In this embodiment, the membrane perdistillation module 23 employs a hydrophobic microporous membrane with a pore size of 0.1-0.5 μm and a porosity of 60%-80%. The seawater side temperature is 60-80°C, and the freshwater side temperature is 40-60°C. The vapor pressure difference generated by the temperature difference drives water vapor through the membrane pores from the seawater side to the freshwater side, where it condenses to form freshwater. This process does not require heating the seawater to boiling, resulting in low energy consumption and making it particularly suitable for utilizing low-temperature waste heat.

[0047] As one or more implementation methods, the regional cooling and heating subsystem is divided into an absorption cooling module and a heat exchanger heating module, including a steam generator 30, a second condenser 31, a first pressure reducing valve 32, an evaporator 33, an absorber 34, a second pressure reducing valve 35, a circulating pump 36, a heat exchanger 37, and a second water supply pump 38.

[0048] The first inlet of the steam generator 30 is connected to the second outlet of the hot end of the second waste heat boiler 22, receiving low-temperature flue gas (80-150℃) from the second waste heat boiler 22; the first outlet of the steam generator 30 is connected to the hot end inlet of the second condenser 31, and the separated water vapor enters the second condenser 31 for condensation; the hot end outlet of the second condenser 31 is connected to the first pressure reducing valve 32, and the condensate enters the evaporator 33 after pressure reduction; the first pressure reducing valve 32 is connected to the first inlet of the evaporator 33, and one outlet of the evaporator 33 is connected to the first inlet of the absorber 34, and the evaporated water vapor enters the absorber 34; the outlet of the absorber 34 is connected to the circulating pump 36, and the circulating pump 36 is connected to the second inlet of the steam generator 30, so that the lithium bromide solution is recycled.

[0049] The second outlet of the steam generator 30 is connected to the second pressure reducing valve 35, which is connected to the second inlet of the absorber 34. The concentrated lithium bromide solution enters the absorber 34 after pressure reduction. The third outlet of the steam generator 30 is connected to the hot end inlet of the heat exchanger 37. The used flue gas (approximately 60-80°C) enters the heat exchanger 37 for further waste heat recovery. The flue gas is discharged to the atmosphere at the hot end outlet of the heat exchanger 37. The second feed water pump 38 is connected to the cold end inlet of the heat exchanger 37. Domestic water enters the heat exchanger 37 to absorb the waste heat from the flue gas, and the resulting hot water (40-60°C) flows to the user at the cold end outlet of the heat exchanger 37.

[0050] In this embodiment, absorption refrigeration uses a lithium bromide-water working fluid pair, with low-temperature flue gas at 80-150°C as the driving heat source. In the steam generator 30, the dilute lithium bromide solution is heated, and water vapor is separated out. The water vapor is condensed into liquid water in the second condenser 31, and after being depressurized by the first pressure reducing valve 32, it enters the evaporator 33. In the evaporator 33, the low-pressure water absorbs heat from the chilled water and evaporates, producing a cooling effect. The water vapor enters the absorber 34 and is absorbed by the concentrated lithium bromide solution, and the absorbed heat is carried away by the cooling water. The absorbed dilute solution is returned to the steam generator 30 via the circulation pump 36, completing the cycle.

[0051] The workflow of the integrated power generation, heating, cooling, and freshwater supply system described in this embodiment is as follows: (1) Start the proton exchange membrane fuel cell power generation system Hydrogen in hydrogen storage tank 1 is pressurized to 0.3 MPa by first hydrogen compressor 2, humidified to 90% relative humidity in hydrogen humidifier 3, and preheated to 70°C in hydrogen preheater 4 before entering the anode of proton exchange membrane fuel cell 8. Simultaneously, air is pressurized to 0.3 MPa by first air compressor 5, humidified to 90% relative humidity in air humidifier 6, and preheated to 70°C in air preheater 7 before entering the cathode of proton exchange membrane fuel cell 8. Inside the fuel cell, hydrogen and air undergo an electrochemical reaction, generating direct current and heat of reaction. The heat of reaction is carried away by cooling water at approximately 80°C.

[0052] (2) Start the micro gas turbine generator system The unreacted hydrogen gas (approximately 10%) at the anode of the proton exchange membrane fuel cell 8 is pressurized to 1.5 MPa by the second hydrogen compressor 9. The cathode exhaust gas is pressurized to 0.8 MPa by the second air compressor 11, cooled to 50°C by the intercooler 12, and then pressurized again to 1.5 MPa by the third air compressor 13. It then enters the afterburner 10 along with the pressurized hydrogen gas for combustion, producing high-temperature flue gas at 1000°C. This high-temperature flue gas enters the micro gas turbine 14 to drive the gas turbine to generate electricity, and the outlet flue gas temperature drops to 500°C.

[0053] (3) Start the micro steam turbine generator system Medium-temperature flue gas at 500℃ enters the first waste heat boiler 15, heating water to generate steam at 350℃. The steam then enters the micro steam turbine 16 to generate electricity. The exhaust steam (120℃) after generating electricity enters the first condenser 17 and condenses into liquid water. The condensate is preheated to 110℃ by the regenerator 19 and then returned to the first waste heat boiler 15. The outlet flue gas temperature of the first waste heat boiler 15 drops to 120℃.

[0054] (4) Start the membrane permeate distillation desalination subsystem The 80°C cooling water from the proton exchange membrane fuel cell 8, after preheating the air and hydrogen in the air preheater 7 and hydrogen preheater 4, cools to 70°C. It then enters the second waste heat boiler 22 along with the 120°C low-temperature flue gas from the outlet of the first waste heat boiler 15, heating the seawater to 70°C. The 70°C seawater enters the seawater side of the membrane perdistillation module 23, while the freshwater in the freshwater storage tank 28, after being preheated to 50°C by the first preheater 24, enters the freshwater side of the membrane perdistillation module 23. Driven by the temperature difference, water vapor from the seawater side passes through the hydrophobic microporous membrane into the freshwater side and condenses, producing new freshwater. The newly produced freshwater returns to the freshwater storage tank 28, and the concentrated brine returns to the seawater storage tank 26. A portion of the freshwater in the freshwater storage tank 28 is pumped by the first water pump 21 to the air humidifier 6 and the hydrogen humidifier 3 for humidification.

[0055] (5) Activate the regional cooling and heating subsystem The 100°C low-temperature flue gas from the outlet of the second waste heat boiler 22 enters the steam generator 30, heating the dilute lithium bromide solution to produce steam. The steam is condensed in the second condenser 31 and depressurized by the first pressure reducing valve 32 before entering the evaporator 33, where it absorbs heat from the chilled water to produce 7°C chilled water for user cooling. The steam then enters the absorber 34 and is absorbed by the concentrated lithium bromide solution; the absorbed heat is carried away by the cooling water. The absorbed dilute solution returns to the steam generator 30 via the circulating pump 36. The 80°C flue gas flowing out of the steam generator 30 enters the heat exchanger 37, heating domestic water to 50°C for user heating. Finally, the flue gas is discharged into the atmosphere at 40°C.

[0056] This embodiment highly integrates subsystems such as proton exchange membrane fuel cell, gas turbine, steam turbine, membrane distillation for desalination, and absorption refrigeration to construct a combined cooling-heating-water-electricity (CCHP) system. This not only achieves cascaded energy utilization but also significantly improves overall energy efficiency and system flexibility by optimizing the thermodynamic coupling and material circulation between subsystems. By adding an afterburner at the PEMFC outlet, unreacted fuel is secondary-burned to generate high-grade heat energy, driving the gas turbine and steam turbine to generate electricity. This achieves deep energy recovery from fuel cell exhaust gases, effectively solving the problem of low exhaust gas utilization in traditional PEMFC systems. Using hydrogen as the primary fuel, the PEMFC power generation process only produces water vapor. Combined with complete combustion and exhaust gas treatment in the afterburner, the system achieves near-zero carbon emissions. When combined with a carbon capture and utilization device, the system structure has excellent renewable energy integration capabilities, allowing coupling with clean energy sources such as solar and wind power to further increase the system's green energy ratio and adapt to future energy structure transformation needs.

[0057] Example 2 Embodiment 2 of the present invention introduces a multi-generation system integrating electricity, heat, cooling and fresh water, which adopts the multi-generation system integrating electricity, heat, cooling and fresh water introduced in Embodiment 1.

[0058] A multi-generation system integrating electricity, heat, cooling, and freshwater supply includes: Step S01: Hydrogen and air are preheated, humidified and pressurized respectively before entering the high-temperature proton exchange membrane fuel cell to undergo a chemical reaction, converting chemical energy into electrical energy; Specifically, the hydrogen in the hydrogen storage tank 1 is first pressurized to 0.2-0.5 MPa in the first hydrogen compressor 2, then flows into the hydrogen humidifier 3 to be humidified to a relative humidity of 80%-100%, and then flows into the hydrogen preheater 4 to be preheated to 60-80°C. At the same time, air flows from the outside into the first air compressor 5 to be pressurized to 0.2-0.5 MPa, then flows into the air humidifier 6 to be humidified to a relative humidity of 80%-100%, and then flows into the air preheater 7 to be preheated to 60-80°C. Together with the pressurized, humidified, and preheated hydrogen, the air flows into the proton exchange membrane fuel cell 8 to carry out an electrochemical reaction to generate electricity. The heat of reaction is discharged through cooling water at a temperature of 70-90°C.

[0059] Step S02: The remaining hydrogen at the anode and the tail gas at the cathode of the proton exchange membrane fuel cell are pressurized and then enter the after-combustion chamber for combustion to generate high-temperature flue gas. The generated high-temperature flue gas drives the gas turbine to rotate and do work. The flue gas after doing work is transformed into medium-temperature flue gas. Specifically, the residual hydrogen at the anode outlet of the proton exchange membrane fuel cell 8 enters the second hydrogen compressor 9 and is pressurized to 1.0-2.0 MPa. At the same time, the cathode exhaust gas of the proton exchange membrane fuel cell 8 flows into the second air compressor 11 for the first pressurization to 0.5-1.0 MPa. Subsequently, the cathode exhaust gas enters the intercooler 12 for cooling to 40-60°C and continues to flow into the third air compressor 13 for the second pressurization to 1.0-2.0 MPa. After pressurization, the hydrogen and cathode exhaust gas enter the afterburner 10 together and are mixed and burned to produce high-temperature flue gas of 800-1200°C. The high-temperature flue gas then enters the micro gas turbine 14 to drive the gas turbine to rotate and generate electricity. At the same time, the flue gas flows out from the outlet of the micro gas turbine 14 and is transformed into medium-temperature flue gas of 400-600°C.

[0060] Step S03: Medium-temperature flue gas heats the water in the waste heat boiler to make it evaporate. The steam enters the steam turbine to drive the steam turbine to rotate and do work. The exhaust steam after doing work is condensed and returned to the waste heat boiler. Specifically, the medium-temperature flue gas flowing out of the micro gas turbine 14 enters the first waste heat boiler 15 to heat water and generate steam at 300-400°C. The steam then enters the micro steam turbine 16 to drive the steam turbine to rotate and generate electricity. The steam after doing work enters the first condenser 17. At the same time, the first feedwater pump 20 draws liquid water at 20-30°C from the outside to absorb the heat of the steam and condense it. The condensate is transported to the regenerator 19 by the condensate pump 18. Meanwhile, some steam is drawn from the steam turbine and transported to the regenerator 19 to preheat the liquid water to 100-150°C. The preheated liquid water re-enters the waste heat boiler to participate in the next cycle. The flue gas temperature at the outlet of the first waste heat boiler 15 drops to 80-150°C.

[0061] Step S04: The cooling water of the proton exchange membrane fuel cell and the low-temperature flue gas from the outlet of the first waste heat boiler heat the seawater together. The heated seawater and the preheated fresh water enter the membrane distillation module at the same time to produce new fresh water. Specifically, the cooling water of the proton exchange membrane fuel cell 8, after preheating hydrogen and air, enters the second waste heat boiler 22 along with the 80-150°C low-temperature flue gas from the hot end outlet of the first waste heat boiler 15 to heat seawater. The seawater is supplied by the seawater storage tank 26, heated to 60-80°C, and then flows out and enters the membrane perdistillation module 23. At the same time, ambient freshwater flows out from the freshwater storage tank 28, is preheated to 40-60°C by the first preheater 24, and then enters the membrane perdistillation module 23. Inside the membrane perdistillation module 23, due to the higher temperature on the seawater side, some water is separated from the seawater in the form of water vapor. Under the pressure difference caused by the temperature difference on both sides, the water enters the freshwater side through the porous membrane. At the same time, it is condensed on the lower-temperature freshwater side and turns into liquid water, which flows out of the membrane perdistillation module 23 along with the original freshwater. Then, it is transported back to the freshwater storage tank 28 by the second water pump 29. Meanwhile, the waste liquid from the seawater desalination process enters the first preheater 24 to preheat the freshwater that is about to enter the membrane perdistillation module 23, and is transported to the seawater storage tank 26 by the seawater pump 25. At the same time, the water required for humidifying the air and hydrogen in the proton exchange membrane fuel cell power generation system is transported by the freshwater storage tank 28 by the first water pump 21.

[0062] Step S05: The low-temperature flue gas from the outlet of the second waste heat boiler first heats the steam generator of the absorption refrigeration system, causing water vapor to separate from the lithium bromide solution. After condensation and evaporation, refrigeration is achieved. Subsequently, the low-temperature flue gas enters the heat exchanger to provide waste heat to the liquid water for heating.

[0063] Specifically, the low-temperature flue gas (80-150°C) flowing from the second waste heat boiler 22 enters the steam generator 30 and heats the lithium bromide solution, thereby separating the water vapor. The water vapor then enters the second condenser 31 and condenses into liquid water at 30-40°C. The liquid water then flows out of the second condenser 31 and enters the first pressure reducing valve 32 to reduce its pressure to 0.5-2 kPa. The water at this low pressure enters the evaporator 33, where it absorbs heat from chilled water at 5-15°C and evaporates to form water vapor, producing a cooling effect. Subsequently, the water vapor enters the absorber 34, and... The lithium bromide concentrated solution, which has lost some water, enters the absorber 34 through the second pressure reducing valve 35 to absorb water vapor. The heat generated during the process is absorbed and carried away by the cooling water. The mixed lithium bromide solution then re-enters the steam generator 30 under the action of the circulating pump 36 for the next round of refrigeration. Subsequently, the low-temperature flue gas flows out of the steam generator 30 and enters the heat exchanger 37. At the same time, the second feed water pump 38 delivers liquid water to the heat exchanger 37 to exchange heat with the low-temperature flue gas to generate hot water at 40-60°C for user use. Finally, the flue gas is discharged into the atmosphere.

[0064] The combined heat and power (CHP) method in this embodiment utilizes five levels of energy cascade to sequentially convert the chemical energy of fuel into electrical energy, medium-temperature thermal energy, and low-temperature thermal energy, ultimately achieving integrated power supply, fresh water supply, cooling, and heating, with a comprehensive energy utilization efficiency of over 85%.

[0065] The detailed steps are the same as the working principle of the integrated power supply system (power-heat-cooling-freshwater) provided in Example 1, and will not be repeated here.

[0066] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0067] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0068] The above description is merely a preferred embodiment of this practice and is not intended to limit the scope of this practice. Various modifications and variations can be made to this practice by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this practice should be included within the protection scope of this practice.

Claims

1. A multi-generation system integrating electricity, heat, cooling, and freshwater supply, characterized in that, The system includes a proton exchange membrane fuel cell power generation system, a micro gas turbine power generation system, a micro steam turbine power generation system, a membrane permeate distillation desalination subsystem, and a regional cooling and heating subsystem, all connected by pipes and valves. The proton exchange membrane fuel cell power generation system is connected to the micro gas turbine power generation system; the micro gas turbine power generation system is connected to the micro steam turbine power generation system; the micro steam turbine power generation system is connected to the membrane permeate distillation desalination subsystem; and the membrane permeate distillation desalination subsystem is connected to both the regional cooling and heating subsystem and the proton exchange membrane fuel cell power generation system.

2. The integrated power supply system combining electricity, heat, cooling, and fresh water as described in claim 1, characterized in that, The proton exchange membrane fuel cell power generation system includes a hydrogen storage tank, a first hydrogen compressor, a hydrogen humidifier, a hydrogen preheater, a first air compressor, an air humidifier, an air preheater, and a proton exchange membrane fuel cell. The first air compressor is connected to an external source, and is connected to the air humidifier. The air humidifier is connected to the air preheater, and the air preheater is connected to the cathode of the proton exchange membrane fuel cell. The hydrogen storage tank stores hydrogen fuel. The first hydrogen compressor is connected to the hydrogen storage tank, the hydrogen humidifier is connected to the first hydrogen compressor, the hydrogen preheater is connected to the hydrogen humidifier, and the hydrogen preheater is connected to the anode of the proton exchange membrane fuel cell. The air humidifier is connected to the hydrogen humidifier.

3. A multi-generation system integrating electricity, heat, cooling, and freshwater as described in claim 2, characterized in that, The membrane perdistillation desalination subsystem includes a first water pump, a second waste heat boiler, a membrane perdistillation assembly, a first preheater, a seawater pump, a seawater storage tank, a seawater feed pump, a desalination storage tank, and a second water pump; wherein, the first hot-end inlet of the second waste heat boiler is connected to the air preheater, the second hot-end inlet of the second waste heat boiler is connected to the first waste heat boiler, and the first hot-end outlet of the second waste heat boiler is connected to the cooling water inlet of the proton exchange membrane fuel cell; The cold end inlet of the second waste heat boiler is connected to the outlet of the seawater storage tank, the cold end outlet of the second waste heat boiler is connected to the seawater side inlet of the membrane perdistillation assembly, the seawater side outlet of the membrane perdistillation assembly is connected to the hot end inlet of the first preheater, the hot end outlet of the first preheater is connected to the seawater pump, the seawater pump is connected to the first inlet of the seawater storage tank, and the seawater feed pump is connected to the second inlet of the seawater storage tank. The first outlet of the freshwater storage tank is connected to the cold end inlet of the first preheater, the cold end outlet of the first preheater is connected to the freshwater side inlet of the membrane permeation distillation assembly, the freshwater side outlet of the membrane permeation distillation assembly is connected to the second water pump, the second water pump is connected to the first inlet of the freshwater storage tank, the second outlet of the freshwater storage tank is connected to the first water pump, and the first water pump is connected to the air humidifier.

4. A multi-generation system integrating electricity, heat, cooling, and freshwater as described in claim 3, characterized in that, The regional cooling and heating subsystem includes a steam generator, a second condenser, a first pressure reducing valve, an evaporator, an absorber, a second pressure reducing valve, a circulating pump, a heat exchanger, and a second feedwater pump. The first inlet of the steam generator is connected to the second outlet of the hot end of the second waste heat boiler; the first outlet of the steam generator is connected to the hot end inlet of the second condenser; the hot end outlet of the second condenser is connected to the first pressure reducing valve; the first pressure reducing valve is connected to the first inlet of the evaporator; the first outlet of the evaporator is connected to the first inlet of the absorber; the outlet of the absorber is connected to the circulating pump; and the circulating pump is connected to the second inlet of the steam generator. The second outlet of the steam generator is connected to the second pressure reducing valve, and the second pressure reducing valve is connected to the second inlet of the absorber; The third outlet of the steam generator is connected to the hot end inlet of the heat exchanger, and the flue gas is discharged to the atmosphere at the hot end outlet of the heat exchanger. The second water pump is connected to the cold end inlet of the heat exchanger, and the hot water flows to the user at the cold end outlet of the heat exchanger.

5. A multi-generation system integrating electricity, heat, cooling, and freshwater as described in claim 1, characterized in that, The micro gas turbine power generation system includes a second hydrogen compressor, an afterburner, a second air compressor, an intercooler, a third air compressor, and a micro gas turbine. The second hydrogen compressor is connected to the anode of the proton exchange membrane fuel cell, the second air compressor is connected to the cathode of the proton exchange membrane fuel cell, the intercooler is connected to the second air compressor, the third air compressor is connected to the intercooler, the afterburner is connected to the third air compressor and the second hydrogen compressor, and the afterburner is connected to the micro gas turbine.

6. A multi-generation system integrating electricity, heat, cooling, and freshwater as described in claim 1, characterized in that, The micro steam turbine power generation system includes a first waste heat boiler, a micro steam turbine, a first condenser, a condensate pump, a regenerator, and a first feedwater pump; wherein, the first waste heat boiler is connected to the micro gas turbine, the micro steam turbine is connected to the hot end inlet of the first condenser, the condensate pump is connected to the hot end outlet of the first condenser, the condensate pump is connected to the second inlet of the regenerator, the micro steam turbine is connected to the first inlet of the regenerator, and the first feedwater pump is connected to the cold end inlet of the first condenser.

7. A method for integrating power generation, heating, cooling, and freshwater supply, comprising a power generation, heating, cooling, and freshwater supply system as described in any one of claims 1-6, characterized in that... include: Based on the proton exchange membrane fuel cell power generation system, hydrogen and air enter the high-temperature proton exchange membrane fuel cell after being preheated, humidified and pressurized in sequence, converting chemical energy into electrical energy. The remaining hydrogen at the anode of the proton exchange membrane fuel cell and the tail gas at the cathode enter the micro gas turbine power generation system together. Hydrogen and air are pressurized and then enter the combustion chamber to burn and produce high-temperature flue gas. The generated high-temperature flue gas drives the gas turbine to rotate and do work. After rotating and doing work, the high-temperature flue gas is transformed into medium-temperature flue gas and then enters the micro steam turbine generator system. The waste heat boiler is heated by medium-temperature flue gas, causing the water in it to evaporate. The evaporated water vapor enters the steam turbine, drives the steam turbine to rotate and do work, and then flows out from the outlet. It then enters the condenser and turns into liquid water, which flows into the regenerator. Some steam is separated from the steam turbine and flows into the regenerator to preheat the condensate. The preheated water then enters the next cycle. The desalination subsystem via membrane permeate distillation heats seawater together with cooling water from the proton exchange membrane fuel cell and low-temperature flue gas from the first waste heat boiler. The heated seawater and preheated desalination water then enter the membrane distillation module to produce new desalination water. The desalination water and seawater return to their respective storage tanks, while the cooling water flows into the proton exchange membrane fuel cell for the next round of cooling. In the regional cooling and heating subsystem, the steam generator for low-temperature flue gas heating absorption refrigeration from the second waste heat boiler separates water vapor from the lithium bromide solution. After condensation and evaporation, the refrigeration is completed. The low-temperature flue gas enters the heat exchanger to provide heat energy to the liquid water and is then discharged into the atmosphere. The liquid water, after absorbing heat, can be used to heat users.

8. A multi-generation system integrating electricity, heat, cooling, and freshwater as described in claim 7, characterized in that, Hydrogen gas from the hydrogen storage tank is pressurized by injecting it into the first hydrogen compressor, then flows into the hydrogen humidifier for humidification, and then into the hydrogen preheater for preheating. At the same time, air flows into the first air compressor from the outside for pressurization, is humidified by the air humidifier, and then flows into the air preheater for preheating. Together with the pressurized, humidified, and preheated hydrogen gas, the air flows into the proton exchange membrane fuel cell to undergo an electrochemical reaction to generate electricity. The residual hydrogen at the anode outlet of the proton exchange membrane fuel cell enters the second hydrogen compressor for pressurization. Simultaneously, the cathode exhaust gas of the proton exchange membrane fuel cell flows into the second air compressor for initial pressurization. The cathode exhaust gas then enters the intercooler for cooling and continues to flow into the third air compressor for a second pressurization to reach the rated pressure. After pressurization, the hydrogen and cathode exhaust gas enter the afterburner and mix and burn to produce high-temperature flue gas. The high-temperature flue gas then flows out from the outlet and enters the micro gas turbine to drive the gas turbine to rotate and do work. At the same time, the flue gas flows out from the outlet of the micro gas turbine and transforms into medium-temperature flue gas to provide heat energy for subsequent subsystems.

9. A multi-generational power supply method integrating electricity, heat, cooling, and freshwater as described in claim 7, characterized in that, The medium-temperature flue gas flowing out of the micro gas turbine enters the first waste heat boiler to heat water and generate steam. The steam enters the micro steam turbine to drive the steam turbine to rotate and do work. The steam after doing work enters the first condenser. At the same time, the first feedwater pump draws liquid water from the outside to absorb the heat of the steam and condense the steam. The condensate is transported to the regenerator by the condensate pump. Some steam is drawn from the steam turbine and transported to the regenerator to preheat the liquid water. The preheated liquid water re-enters the waste heat boiler to participate in the next cycle. In a proton exchange membrane fuel cell, cooling water, after preheating hydrogen and air, enters a second waste heat boiler along with low-temperature flue gas from the hot end outlet of the first waste heat boiler to heat seawater. The seawater is supplied from a seawater storage tank; a seawater feed pump supplies seawater to the storage tank. The seawater is heated to a rated temperature in the second waste heat boiler and flows out into the membrane perdistillation module. Freshwater under ambient conditions flows from a freshwater storage tank, is preheated by a first preheater, and then enters the membrane perdistillation module. Inside the membrane perdistillation module, the seawater side has a higher temperature, and some water separates from the seawater as steam. The water is separated from the oxygen supply and, under the pressure difference caused by the temperature difference on both sides, passes through a porous membrane into the freshwater side. Simultaneously, under the condensation effect of the lower-temperature freshwater side, it transforms into liquid water and flows out of the membrane perdistillation module along with the original freshwater. Then, it is transported back to the freshwater storage tank by the second water pump. At the same time, the waste liquid from the seawater desalination process enters the first preheater to preheat the freshwater that is about to enter the membrane perdistillation module, and is then transported to the seawater storage tank by the seawater pump. Meanwhile, the water required for humidifying the air and hydrogen in the proton exchange membrane fuel cell power generation system is transported from the freshwater storage tank by the first water pump.

10. A multi-generational power supply method integrating electricity, heat, cooling, and freshwater as described in claim 7, characterized in that, The low-temperature flue gas flowing from the second waste heat boiler enters the steam generator, heating the lithium bromide solution to separate water vapor. It then enters the second condenser and condenses into liquid water. The liquid water flows out of the second condenser and into the first pressure-reducing valve, maintaining a low-pressure state. This low-pressure water enters the evaporator, where it absorbs heat from the lower-temperature working fluid to evaporate and form water vapor. Meanwhile, the chilled water on the other side of the evaporator releases heat for refrigeration. The water vapor enters the absorber, where the partially dehydrated concentrated lithium bromide solution passes through the second pressure-reducing valve and absorbs the water vapor. The heat generated during this process is absorbed and carried away by the cooling water. The mixed lithium bromide solution then re-enters the steam generator under the action of the circulating pump for the next round of refrigeration. The low-temperature flue gas flows out of the steam generator and enters the heat exchanger. The second feedwater pump delivers liquid water to the heat exchanger to exchange heat with the low-temperature flue gas to produce hot water for user use. Finally, the flue gas is discharged into the atmosphere.

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