Multi-energy coupling seawater desalination and power generation system driven by gas engine

Abstract

The invention relates to the technical field of seawater desalination and power generation, and discloses a multi-energy coupling seawater desalination and power generation system driven by a gas engine, comprising: a refrigerant circulation unit comprising a compressor, a condenser and an evaporator which are connected with each other; the gas engine driving unit comprises a gas engine, a cylinder sleeve heat exchanger and a flue gas heat exchanger, the gas engine is connected with the compressor, and the cylinder sleeve heat exchanger and the flue gas heat exchanger are respectively connected with the gas engine; the membrane distillation unit comprises a seawater storage tank, a membrane assembly, a concentrated solution storage tank and a condensed water tank, the seawater storage tank is connected with the membrane assembly through a condenser, the membrane assembly is connected with the concentrated solution storage tank, and the membrane assembly is connected with the condensed water tank through an evaporator; and the reverse electrodialysis pile unit comprises a reverse electrodialysis pile, a user and a waste liquid tank, and the reverse electrodialysis pile is respectively connected with the user and the waste liquid tank. Through multi-energy coupling and waste heat gradient utilization, the seawater desalination and power generation efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of seawater desalination and power generation technology, and in particular to a gas turbine-driven multi-energy coupled seawater desalination and power generation system. Background Technology

[0002] With the increasing scarcity of freshwater resources globally, seawater desalination technology has received widespread attention as an important means of alleviating the water crisis. Traditional seawater desalination methods, such as reverse osmosis (RO), multi-stage flash distillation (MSF), and multi-effect distillation (MED), generally suffer from high energy consumption, high operating costs, and significant environmental impacts. Meanwhile, the efficient and clean utilization of fossil fuels coupled with the development of renewable energy has become a new trend in energy system development.

[0003] In recent years, membrane distillation (MD), as a novel thermally driven seawater desalination technology, has gradually become a research hotspot due to its advantages such as operation at lower temperatures, low requirements for feed water quality, and high product water purity. However, the membrane distillation process still requires a stable heat source supply, and its energy efficiency is low when operating alone, making large-scale application difficult. Existing membrane distillation systems typically only focus on the heat source supply issue, without fully considering the recovery of cold energy on the condenser side and the synergistic enhancement mechanism of heat and cold, resulting in limited overall system energy utilization efficiency. Furthermore, concentrated brine, as a byproduct of seawater desalination, not only wastes resources if directly discharged, but may also cause ecological problems.

[0004] On the other hand, as a highly efficient internal combustion power device, gas turbine engines generate electricity or drive compressors, but their cylinder liner cooling water and high-temperature flue gas contain a large amount of medium- and low-temperature waste heat. If this waste heat is not effectively recovered and utilized, it will result in energy waste. Existing waste heat utilization methods are mostly single-stage heat exchange or simple heating forms, failing to achieve deep coupling with the seawater desalination process, let alone constructing a multi-stage cascade utilization structure. Reverse electrodialysis (RED) technology can utilize the salinity difference between concentrated brine and fresh water to generate electricity, providing a new path for the resource utilization of concentrated brine. However, in existing technologies, RED often exists as an independent power generation module, lacking system-level collaborative design with the heat-driven desalination system.

[0005] Therefore, there is an urgent need for a multi-energy coupling system that integrates gas engine drive, refrigeration cycle, membrane distillation and reverse electrodialysis power generation to achieve integrated synergy of energy cascade utilization, efficient seawater desalination and concentrated brine resource power generation. Summary of the Invention

[0006] The purpose of this invention is to provide a gas turbine-driven multi-energy coupled seawater desalination and power generation system, which aims to solve the above-mentioned problems and realize energy cascade utilization, efficient seawater desalination and concentrated brine resource power generation.

[0007] This invention provides a gas turbine-driven multi-energy coupled seawater desalination and power generation system, comprising: A refrigerant cycle unit includes a compressor, condenser, expansion valve, and evaporator connected to each other; A gas engine drive unit includes a gas engine, a cylinder liner heat exchanger, and a flue gas heat exchanger. The gas engine is connected to the compressor, and the cylinder liner heat exchanger and the flue gas heat exchanger are respectively connected to the gas engine. A membrane distillation unit includes a seawater storage tank, a membrane module, a concentrate storage tank, and a condensate tank. The seawater storage tank is connected to the membrane module via a condenser. The membrane module is connected to the concentrate storage tank. The membrane module is also connected to the evaporator and the condensate tank, respectively. The reverse electrodialysis stack unit includes a reverse electrodialysis stack, a user, and a waste liquid tank. The reverse electrodialysis stack is connected to the membrane module through a concentrate storage tank, and the reverse electrodialysis stack is connected to the user and the waste liquid tank respectively.

[0008] Preferably, the condenser includes condenser tubes and condenser shell, and the evaporator includes evaporator tubes and evaporator shell; The compressor outlet is connected to the condenser inlet, the condenser outlet is connected to the evaporator inlet via an expansion valve, and the evaporator outlet is connected to the compressor inlet. Low-temperature, low-pressure refrigerant vapor enters the compressor and is compressed into high-temperature, high-pressure superheated vapor. The high-temperature, high-pressure superheated vapor enters the condenser tubes of the condenser, where it releases heat and is condensed into high-pressure, room-temperature refrigerant liquid. The refrigerant liquid flows through the expansion valve, where it is throttled and depressurized, becoming a low-temperature, low-pressure gas-liquid mixture. The gas-liquid mixture enters the evaporator tubes of the evaporator, absorbs heat, evaporates, and becomes low-temperature, low-pressure refrigerant vapor again, returning to the compressor to complete one refrigerant cycle, which is repeated continuously.

[0009] Preferably, the gas engine is connected to the compressor, and the gas engine is used to drive the compressor to operate; The cylinder heat exchanger includes an outer cylinder liner and an inner cylinder liner, and the flue gas heat exchanger includes a flue gas liner and a heat exchanger shell. The inner cylinder liner is disposed inside the gas engine. The inlet of the outer cylinder liner is connected to the outlet of the condenser shell. The outlet of the outer cylinder liner is connected to the inlet of the heat exchanger shell. The outlet of the heat exchanger shell is connected to the inlet of the membrane module. The flue gas outlet of the gas engine is connected to the inlet of the flue gas liner. The outlet of the flue gas liner is connected to the outside.

[0010] Preferably, the membrane distillation unit further includes a seawater pump, the inlet of the seawater storage tank is connected to the pretreated seawater source, the outlet of the seawater storage tank is connected to the inlet of the seawater pump, and the outlet of the seawater pump is connected to the inlet of the condenser shell.

[0011] Preferably, the membrane distillation unit further includes a condensate pump and a freshwater storage tank; The concentrate outlet of the membrane module is connected to the inlet of the concentrate storage tank, the freshwater outlet of the membrane module is connected to the inlet of the condensate tank through an auxiliary cooler, the condensate tank outlet is connected to the inlet of the condensate pump, and the condensate pump outlet is connected to the inlet of the freshwater storage tank.

[0012] Preferably, the membrane distillation unit further includes a freshwater storage tank, which is connected to the condensate tank.

[0013] Preferably, the inlet of the reverse electrodialysis stack is connected to the pretreated seawater source, and the outlet of the reverse electrodialysis stack is connected to the inlet of the waste liquid tank.

[0014] Preferably, the inlet of the reverse electrodialysis stack is also connected to the outlet of the concentrate storage tank via a concentrate pump.

[0015] Preferably, the power generation side of the reverse electrodialysis stack is connected to the user.

[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention achieves efficient cascaded utilization of energy. The gas engine not only directly drives the compressor to operate the refrigerant cycle, but its cylinder liner heat exchanger and flue gas heat exchanger respectively recover medium- and low-temperature waste heat and high-temperature flue gas heat, jointly providing a stable heat source for the membrane distillation unit. This forms a multi-stage energy input structure driven by mechanical energy and utilizing waste heat in stages, avoiding the direct downgrading of high-grade energy and significantly improving the comprehensive utilization efficiency of primary energy. The refrigerant cycle unit supplies heat to the feed liquid (seawater) through the condenser, while the evaporator is used to condense the water vapor generated by membrane distillation, forming a temperature difference driving mechanism of "hot-side heating - cold-side condensation," constructing a synergistic enhancement structure on both hot and cold sides, thus improving the heat transfer and... The mass transfer process is more stable, effectively improving membrane distillation flux and water production efficiency. The high-concentration brine produced by membrane distillation is stored in a concentrate tank and input as a high-concentration electrolyte to the reverse electrodialysis stack unit. It forms a salinity gradient with the pretreated seawater, driving ion migration to generate electricity, realizing energy recovery from waste brine, and transforming seawater desalination byproducts from "waste liquid that needs to be disposed of" into "usable energy medium", improving the system's resource utilization level. The electricity generated by the reverse electrodialysis stack can be stored in batteries or directly supplied to users. It can be used for internal electrical equipment (such as pumps and control systems) or for external power supply, forming a multi-functional output mode that combines freshwater production and power output, improving the system's operational flexibility and reliability in off-grid or microgrid scenarios. This invention, through multi-energy coupling and waste heat cascade utilization, not only solves the problems of high energy consumption and concentrated brine disposal in traditional seawater desalination, but also achieves synergistic optimization of energy production, freshwater preparation and power output. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a gas turbine-driven multi-energy coupled seawater desalination and power generation system according to the present invention.

[0019] In the diagram, 1. Compressor; 2. Condenser; 3. Expansion valve; 4. Evaporator; 5. Gas engine; 6. Cylinder liner heat exchanger; 7. Flue gas heat exchanger; 8. Seawater storage tank; 9. Seawater pump; 10. Membrane module; 11. Auxiliary cooler; 12. Condensate tank; 13. Condensate pump; 14. Freshwater storage tank; 15. Concentrate storage tank; 16. Concentrate pump; 17. Reverse electrodialysis stack; 18. User; 19. Waste liquid tank. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0022] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0023] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0024] like Figure 1 As shown, the present invention provides a gas engine-driven multi-energy coupled seawater desalination and power generation system, comprising: a refrigerant circulation unit, a gas engine drive unit, a membrane distillation unit, and a reverse electrodialysis stack unit.

[0025] Specifically, the refrigerant circulation unit includes a compressor 1, a condenser 2, an expansion valve 3, and an evaporator 4 that are connected to each other.

[0026] Understandably, by constructing a closed refrigerant circulation loop to transfer and distribute heat within the system, the required heat source is provided for the membrane distillation process on the one hand, and a cold source is provided for water vapor condensation on the other, thereby driving the seawater desalination process to operate efficiently and stably.

[0027] Specifically, the refrigerant circulation unit consists of a compressor 1, a condenser 2, an expansion valve 3, and an evaporator 4 connected in sequence to form a basic circulation loop. Low-temperature, low-pressure refrigerant vapor first enters the compressor 1, where it is compressed to form high-temperature, high-pressure superheated vapor. This superheated vapor then enters the condenser 2, where it releases heat to an external fluid (such as seawater) and condenses into high-pressure, room-temperature liquid refrigerant. The liquid refrigerant is then depressurized by the expansion valve 3, becoming a low-temperature, low-pressure gas-liquid mixture, which enters the evaporator 4. In the evaporator 4, the refrigerant absorbs heat from the water vapor produced by membrane distillation, evaporating into low-temperature, low-pressure vapor, completing the phase change endothermic process. It then returns to the compressor 1 to begin the next cycle. Through this cycle, the system achieves directional heat transfer from the condensation side (exothermic) to the evaporation side (endothermic), providing both heating and cooling functions for the membrane distillation unit.

[0028] Specifically, the gas engine drive unit includes a gas engine 5, a cylinder liner heat exchanger 6, and a flue gas heat exchanger 7. The gas engine 5 is connected to the compressor 1, and the cylinder liner heat exchanger 6 and the flue gas heat exchanger 7 are respectively connected to the gas engine 5.

[0029] Understandably, by using the gas engine 5 as the core power source, and simultaneously recovering the cylinder liner cooling heat and high-temperature flue gas waste heat generated during its operation, the system can achieve synergistic output of mechanical energy and thermal energy, providing driving power and the thermal energy required for desalination.

[0030] Specifically, the gas engine 5 directly drives the compressor 1 via a mechanical connection, providing the necessary power input to the refrigerant cycle unit. During operation, the gas engine 5 generates a significant amount of heat. Part of this heat is carried away by cooling water through the cylinder cooling system, and this heat is recovered by the cylinder liner heat exchanger 6—connected to the cooling circuit of the gas engine 5, using cooling water as the heat transfer medium to transfer the low-to-medium temperature waste heat to the subsequent process fluids. The remaining heat is discharged from the exhaust port of the gas engine 5 as high-temperature flue gas. The flue gas heat exchanger 7, connected to the flue gas outlet of the gas engine 5, captures and utilizes this high-temperature waste heat. The cylinder liner heat exchanger 6 and the flue gas heat exchanger 7 are connected to the cooling system and exhaust system of the gas engine 5, respectively, forming two independent but complementary waste heat recovery paths. Together, they provide a stable, cascaded heat source for the membrane distillation unit, thereby improving the overall energy efficiency of the system.

[0031] The membrane distillation unit includes a seawater storage tank 8, a membrane module 10, a concentrate storage tank 15, and a condensate tank 12. The seawater storage tank 8 is connected to the membrane module 10 via a condenser 2. The membrane module 10 is connected to the concentrate storage tank 15. The membrane module 10 is also connected to the evaporator 4 and the condensate tank 12.

[0032] It is understandable that a seawater desalination unit with membrane distillation as its core can be constructed to achieve the separation of water and salt through thermal drive, and to effectively collect and store the products, while providing high-concentration brine for subsequent energy recovery.

[0033] Specifically, the seawater storage tank 8 stores pretreated seawater, and its outlet is connected to the shell side of the condenser 2 (or a corresponding heat exchange channel) via a pipeline. In the condenser 2, the seawater is heated by high-temperature refrigerant from the refrigerant circulation unit, and the heated liquid enters the membrane module 10. The membrane module 10 contains a hydrophobic microporous membrane. The heated liquid forms water vapor on one side of the membrane, which passes through the membrane pores and is cooled and condensed on the other side. The remaining unevaporated liquid is concentrated into brine due to salt content, which is discharged from the outlet of the membrane module 10 and temporarily stored in the concentrate storage tank 15 for subsequent use in reverse electrodialysis power generation. The water vapor that permeates through the membrane enters the evaporator 4, which is connected to the cold side of the membrane module 10. In the evaporator 4, it is cooled by low-temperature refrigerant and condensed into fresh water, which flows into the condensate tank 12 for collection. Through the above connections, the membrane distillation unit realizes a complete desalination process, including liquid heating, steam permeation, brine discharge, and fresh water condensation, and forms a thermal coupling with the refrigerant circulation unit to ensure continuous and stable operation.

[0034] The reverse electrodialysis stack unit includes a reverse electrodialysis stack 17, a user 18, and a waste liquid tank 19. The reverse electrodialysis stack 17 is connected to the membrane module 10 through a concentrate storage tank 15, and the reverse electrodialysis stack 17 is connected to the user 18 and the waste liquid tank 19 respectively.

[0035] It is understandable that by utilizing the salinity difference between the concentrated brine produced by the membrane distillation process and the pretreated seawater, the chemical potential energy can be converted into electrical energy through reverse electrodialysis technology. The generated electrical energy and the discharged waste liquid can be effectively managed, thereby realizing the resource utilization of concentrated brine and the recovery of system energy.

[0036] Specifically, the reverse electrodialysis stack 17 consists of multiple compartments formed by alternating cation exchange membranes and anion exchange membranes. High-concentration brine from the concentrate storage tank 15 is transported as a high-concentration electrolyte solution to some compartments of the stack, while pretreated seawater is introduced as a low-concentration electrolyte solution into adjacent compartments. Driven by the salinity gradient, cations and anions migrate directionally through their respective ion exchange membranes, forming an ionic current, which generates usable electrical energy in the external circuit. This electrical energy is transmitted via wires to the user 18 for storage, for use by internal system equipment, or for external output. The concentrated brine after ion migration and the diluted seawater mix to form a low-grade waste liquid, which is discharged from the reverse electrodialysis stack 17 and collected in the waste liquid tank 19 for subsequent treatment or discharge. Through the above connection and operation, the reverse electrodialysis stack unit achieves energy recovery from the concentrated brine, a byproduct of membrane distillation, improving the energy utilization efficiency and resource recycling level of the entire system.

[0037] In some embodiments of this application, the condenser 2 includes a condenser tube and a condenser shell, and the evaporator 4 includes an evaporator tube and an evaporator shell; the outlet of the compressor 1 is connected to the inlet of the condenser tube, the outlet of the condenser tube is connected to the inlet of the evaporator tube through an expansion valve 3, and the outlet of the evaporator tube is connected to the inlet of the compressor 1; low-temperature, low-pressure refrigerant vapor enters the compressor 1 and is compressed into high-temperature, high-pressure superheated vapor; the high-temperature, high-pressure superheated vapor enters the condenser tube of the condenser 2, releases heat, and is condensed into high-pressure, room-temperature refrigerant liquid; the refrigerant liquid flows through the expansion valve 3, and after throttling and pressure reduction, it becomes a low-temperature, low-pressure gas-liquid mixture; the gas-liquid mixture enters the evaporator tube of the evaporator 4, absorbs heat and evaporates, and then becomes low-temperature, low-pressure refrigerant vapor again, returning to the compressor 1 to complete one refrigerant cycle, which is repeated continuously.

[0038] It is understandable that the phase change process of the refrigerant in the condenser 2 and evaporator 4 enables the directional transfer of heat from the high-temperature side to the low-temperature side, providing both a heating source and a condensing source for the membrane distillation unit.

[0039] Specifically, the refrigerant cycle employs a shell-and-tube heat exchange structure: condenser 2 consists of condenser tubes and a condenser shell surrounding the condenser tubes, while evaporator 4 consists of evaporator tubes and an evaporator shell surrounding the evaporator tubes. The compressor 1 outlet is connected to the condenser tube inlet. High-temperature, high-pressure superheated refrigerant vapor enters the condenser tubes, releasing heat to the feed liquid (such as seawater) on the condenser shell side during its flow. It is cooled and condensed into a high-pressure, room-temperature liquid refrigerant. This liquid refrigerant flows out of the condenser tube outlet, is throttled and depressurized by expansion valve 3, and transforms into a low-temperature, low-pressure gas-liquid two-phase mixture. It then enters the evaporator tubes, flows through the evaporator 4, and absorbs heat from the water vapor on the evaporator shell side, evaporating completely to form low-temperature, low-pressure refrigerant vapor. This vapor exits from the evaporator tube outlet, returns to the compressor 1 inlet, and is recompressed, completing a full thermodynamic cycle. This cycle continues, allowing condenser 2 to continuously supply heat to the feed liquid to raise its temperature for membrane distillation, while evaporator 4 continuously absorbs heat from the water vapor generated during membrane distillation to achieve condensation and water production, thus supporting the efficient and stable operation of the entire seawater desalination process.

[0040] In some embodiments of this application, the gas engine 5 is connected to the compressor 1, and the gas engine 5 is used to drive the compressor 1 to operate; the cylinder heat exchanger 6 includes an outer cylinder liner and an inner cylinder liner, and the flue gas heat exchanger 7 includes a flue gas liner and a heat exchanger shell; the inner cylinder liner is disposed inside the gas engine 5, the inlet of the outer cylinder liner is connected to the outlet of the condenser shell, the outlet of the outer cylinder liner is connected to the inlet of the heat exchanger shell, and the outlet of the heat exchanger shell is connected to the inlet of the membrane module 10; the flue gas outlet of the gas engine 5 is connected to the inlet of the flue gas liner, and the outlet of the flue gas liner is connected to the outside.

[0041] Understandably, by simultaneously providing mechanical power and multi-stage waste heat through the gas engine 5, the refrigeration cycle is driven, and a cascaded matching heat energy is supplied to the membrane distillation process, thereby achieving efficient and comprehensive energy utilization. The gas engine 5 is the power core of the system; it burns natural gas to generate mechanical energy, directly driving the compressor 1 in the heat pump cycle. During operation, the engine generates a large amount of high-temperature waste heat, mainly including cylinder liner water heat and high-temperature flue gas. This waste heat is effectively collected sequentially by the waste heat recovery devices: cylinder liner heat exchanger 6 and flue gas heat exchanger 7. The recovered heat is not wasted but used to heat the refrigerated seawater from the condenser 2, significantly improving the system's heating capacity and overall energy efficiency.

[0042] Specifically, the output shaft of the gas engine 5 is directly connected to the compressor 1 to drive the compressor 1 and provide the necessary power for the refrigerant circulation. The heat generated by the gas engine 5 during operation is cooled and exchanged through the inner cylinder liner of the cylinder liner heat exchanger 6 before returning to the gas engine 5, forming a closed cooling circuit. Simultaneously, the heat-absorbing liquid (such as preheated seawater) from the condenser shell side of the condenser 2 flows out from the condenser shell outlet and into the outer cylinder liner inlet of the cylinder liner heat exchanger 6. In the outer cylinder liner, it flows through the outer wall of the inner cylinder liner, absorbing the cooling water released by the cylinder liner. The liquid is further heated by the residual heat from the medium and low temperatures, and then discharged from the outer cylinder liner outlet, entering the inlet of the heat exchanger shell of the flue gas heat exchanger 7. In the flue gas heat exchanger 7, the liquid flows through the heat exchanger shell, while the high-temperature flue gas discharged from the gas engine 5 enters the flue gas inner liner from the flue gas outlet. It flows in the inner liner and transfers heat through the pipe wall to the liquid in the outer shell, further raising its temperature to a level suitable for membrane distillation. The heated liquid is then transported from the heat exchanger shell outlet to the membrane module 10 for desalination treatment. The flue gas after heat exchange is discharged to the outside from the flue gas inner liner outlet. Through the above connection and heat flow path, the system realizes three-stage energy utilization: the mechanical energy of the gas engine 5 drives the compressor 1, the cylinder liner waste heat preheats the liquid, and the flue gas waste heat deeply heats the liquid, effectively improving the overall thermal efficiency and desalination performance.

[0043] In some embodiments of this application, the membrane distillation unit further includes a seawater pump 9, the inlet of the seawater storage tank 8 is connected to a pretreated seawater source, the outlet of the seawater storage tank 8 is connected to the inlet of the seawater pump 9, and the outlet of the seawater pump 9 is connected to the inlet of the condenser shell.

[0044] Understandably, by establishing a stable feed path, it is ensured that the pretreated seawater can flow sequentially through the condenser 2, the cylinder heat exchanger 6, and the flue gas heat exchanger 7 to be heated step by step, and finally enter the membrane module 10 for desalination, thereby ensuring the continuous and controllable operation of the membrane distillation process.

[0045] Specifically, the pretreated seawater source is connected to the inlet of the seawater storage tank 8 to replenish the tank with pretreated seawater that has undergone filtration and impurity removal. The outlet of the storage tank 8 is connected to the inlet of the seawater pump 9, which acts as a circulating power device to pressurize and transport the seawater within the tank. The outlet of the pump 9 is connected to the inlet of the condenser shell of the condenser 2, allowing the seawater to flow through the condenser shell and absorb heat released from the high-temperature refrigerant in the condenser tubes, thus initially raising its temperature. Subsequently, the preheated seawater continues to enter the subsequent cylinder liner heat exchanger 6 and flue gas heat exchanger 7 to further absorb waste heat from the gas engine 5, ultimately reaching the feed temperature required for membrane distillation. By installing the seawater pump 9, the system can precisely control the feed flow rate and pressure, maintaining the stability of the feed conditions for the membrane module 10 and avoiding desalination efficiency reduction or membrane fouling problems caused by gravity supply or pressure fluctuations.

[0046] In some embodiments of this application, the membrane distillation unit further includes a condensate pump 13 and a freshwater storage tank 14; the concentrate outlet of the membrane module 10 is connected to the inlet of the concentrate storage tank 15, the freshwater outlet of the membrane module 10 is connected to the inlet of the condensate tank 12, the outlet of the condensate tank 12 is connected to the inlet of the condensate pump 13, and the outlet of the condensate pump 13 is connected to the inlet of the freshwater storage tank 14.

[0047] In some embodiments of this application, the membrane distillation unit further includes a freshwater storage tank 14, which is connected to a condensate tank 12.

[0048] In some embodiments of this application, the inlet of the reverse electrodialysis stack 17 is connected to a pretreated seawater source, and the outlet of the reverse electrodialysis stack 17 is connected to the inlet of the waste liquid tank 19.

[0049] In some embodiments of this application, the inlet of the reverse electrodialysis stack 17 is also connected to the outlet of the concentrate storage tank 15.

[0050] Specifically, the high-concentration brine produced by the membrane distillation unit is used as a high-concentration electrolyte to supply the reverse electrodialysis stack 17 to construct an effective salinity gradient, thereby driving ion migration and realizing the recovery of electrical energy.

[0051] Specifically, the concentrate storage tank 15 is used to collect and temporarily store the concentrated seawater discharged from the membrane module 10, and its outlet is connected to the high-concentration side inlet of the reverse electrodialysis stack 17 via a pipeline. During the reverse electrodialysis process, the concentrated brine and the low-concentration seawater from the pretreated seawater source are respectively introduced into adjacent compartments in the stack to form a stable salt concentration difference. Driven by this concentration gradient, cations and anions selectively migrate through the cation exchange membrane and anion exchange membrane, respectively, generating ionic current, which is converted into usable electrical energy in the external circuit. By directly connecting the concentrate storage tank 15 to the reverse electrodialysis stack 17, the system realizes the effective resource utilization of the seawater desalination byproduct—concentrated brine, avoiding energy waste and environmental burden caused by direct discharge, while improving the overall system's energy recovery efficiency.

[0052] In some embodiments of this application, the reverse electrodialysis stack 17 is connected to the user 18.

[0053] Specifically, the electrical energy generated by the reverse electrodialysis stack 17 is effectively collected, stored, and used to improve the flexibility and stability of the system's energy utilization and to provide power support for internal electrical equipment or external loads.

[0054] Specifically, the reverse electrodialysis stack 17 generates DC power during operation by utilizing the salinity difference between concentrated brine and fresh water. This power is output through conductors and connected to user 18. User 18, as a power-consuming unit, transforms the power to meet the voltage requirements of different electrical devices, such as powering auxiliary equipment like pumps, valve control modules, and sensors within the system, ensuring the stable operation of all components. Simultaneously, when there is surplus power, it can be connected to the external power grid via a grid connection device, enabling external power output and further improving the system's economic efficiency. Furthermore, to ensure the continuity and reliability of power supply, energy storage devices, such as battery banks, can be installed in the system. During periods of fluctuating power generation from the reverse electrodialysis stack 17 or peak power consumption, the stored power is released to balance power supply and demand, preventing the impact of unstable power supply on user 18's equipment. Through this connection method, the power generated by the reverse electrodialysis stack 17 is fully and flexibly utilized, achieving not only cascaded energy recovery but also enhancing the energy self-sufficiency and external power supply capabilities of the entire multi-energy coupling system. In addition, the system uses multiple valves v1-v6 to control the flow and on / off state of each branch, ensuring the coordinated operation of all parts of the system.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A gas turbine-driven multi-energy coupled seawater desalination and power generation system, characterized in that, include: A refrigerant cycle unit includes a compressor, condenser, expansion valve, and evaporator that are interconnected. A gas engine drive unit includes a gas engine, a cylinder liner heat exchanger, and a flue gas heat exchanger. The gas engine is connected to the compressor, and the cylinder liner heat exchanger and the flue gas heat exchanger are respectively connected to the gas engine. A membrane distillation unit includes a seawater storage tank, a membrane module, a concentrate storage tank, and a condensate tank. The seawater storage tank is connected to the membrane module via a condenser. The membrane module is connected to the concentrate storage tank. The membrane module is also connected to the evaporator and the condensate tank, respectively. The reverse electrodialysis stack unit includes a reverse electrodialysis stack, a user, and a waste liquid tank. The reverse electrodialysis stack is connected to the membrane module through a concentrate storage tank, and the reverse electrodialysis stack is connected to the user and the waste liquid tank respectively.

2. The gas turbine-driven multi-energy coupled seawater desalination and power generation system according to claim 1, characterized in that, The condenser includes condenser tubes and condenser shell, and the evaporator includes evaporator tubes and evaporator shell; The compressor outlet is connected to the condenser inlet, the condenser outlet is connected to the evaporator inlet via an expansion valve, and the evaporator outlet is connected to the compressor inlet. Low-temperature, low-pressure refrigerant vapor enters the compressor and is compressed into high-temperature, high-pressure superheated vapor. The high-temperature, high-pressure superheated vapor enters the condenser tubes of the condenser, where it releases heat and is condensed into high-pressure, room-temperature refrigerant liquid. The refrigerant liquid flows through the expansion valve, where it is throttled and depressurized, becoming a low-temperature, low-pressure gas-liquid mixture. The gas-liquid mixture enters the evaporator tubes of the evaporator, absorbs heat, evaporates, and becomes low-temperature, low-pressure refrigerant vapor again, returning to the compressor to complete one refrigerant cycle, which is repeated continuously.

3. The gas turbine-driven multi-energy coupled seawater desalination and power generation system according to claim 2, characterized in that, The gas engine is connected to the compressor, and the gas engine is used to drive the compressor to operate; The cylinder heat exchanger includes an outer cylinder liner and an inner cylinder liner, and the flue gas heat exchanger includes a flue gas liner and a heat exchanger shell. The inner cylinder liner is disposed inside the gas engine. The inlet of the outer cylinder liner is connected to the outlet of the condenser shell. The outlet of the outer cylinder liner is connected to the inlet of the heat exchanger shell. The outlet of the heat exchanger shell is connected to the inlet of the membrane module. The flue gas outlet of the gas engine is connected to the inlet of the flue gas liner. The outlet of the flue gas liner is connected to the outside.

4. The gas turbine-driven multi-energy coupled seawater desalination and power generation system according to claim 3, characterized in that, The membrane distillation unit also includes a seawater pump. The inlet of the seawater storage tank is connected to the pretreated seawater source, the outlet of the seawater storage tank is connected to the inlet of the seawater pump, and the outlet of the seawater pump is connected to the inlet of the condenser shell.

5. The gas turbine-driven multi-energy coupled seawater desalination and power generation system according to claim 4, characterized in that, The membrane distillation unit also includes a condensate pump and a freshwater storage tank; The concentrate outlet of the membrane module is connected to the inlet of the concentrate storage tank, the freshwater outlet of the membrane module is connected to the inlet of the condensate tank through an auxiliary cooler, the condensate tank outlet is connected to the inlet of the condensate pump, and the condensate pump outlet is connected to the inlet of the freshwater storage tank.

6. The gas turbine-driven multi-energy coupled seawater desalination and power generation system according to claim 5, characterized in that, The membrane distillation unit also includes a freshwater storage tank, which is connected to the condensate tank.

7. The gas turbine-driven multi-energy coupled seawater desalination and power generation system according to claim 6, characterized in that, The inlet of the reverse electrodialysis stack is connected to the pretreated seawater source, and the outlet of the reverse electrodialysis stack is connected to the inlet of the waste liquid tank.

8. The gas turbine-driven multi-energy coupled seawater desalination and power generation system according to claim 7, characterized in that, The inlet of the reverse electrodialysis stack is also connected to the outlet of the concentrate storage tank via a concentrate pump.

9. The gas turbine-driven multi-energy coupled seawater desalination and power generation system according to claim 8, characterized in that, The power generation side of the reverse electrodialysis stack is connected to the user.

Images