A cold electricity supply coupling seawater desalination system

Abstract

This application relates to the field of waste heat refrigeration technology, specifically disclosing a combined cooling, power, and cooling (CCHP) coupled seawater desalination system. The system includes a gas turbine using natural gas as fuel to drive a generator; a seawater vaporization device that uses the flue gas from the gas turbine to heat seawater and generate superheated steam; a waste heat absorption chiller that uses the superheated steam as a driving heat source to produce cooling; an ice maker that uses the cooling produced by the waste heat absorption chiller to freeze seawater into ice; and an ice storage tank that stores the ice produced by the ice maker. The ice storage tank is connected to user cooling equipment via a refrigerant circulation pipeline. The ice melts and releases heat in the ice storage tank to cool the refrigerant, thus providing cooling. The freshwater produced by the condensation of the superheated steam in the waste heat absorption chiller and the freshwater produced by the melting of ice in the ice storage tank are used as the system's freshwater output. This application has the effect of improving the system's primary energy utilization rate.

Description

Technical Field

[0001] This invention relates to the field of waste heat refrigeration technology, and in particular to a combined cooling and power coupled seawater desalination system. Background Technology

[0002] In coastal areas and island settings, electricity, cooling, and fresh water are three basic needs. Currently, these three needs are typically met by separate systems: gas generator sets provide independent power, electric compression refrigeration units provide independent cooling, and reverse osmosis or low-temperature multi-effect distillation units desalinate seawater independently.

[0003] The fundamental problem with the above-mentioned energy distribution scheme is that there is no energy cascade utilization mechanism along the temperature decrease path between primary energy and terminal cooling, electricity and water production, resulting in low comprehensive utilization rate of primary energy.

[0004] Specifically, when natural gas is used as a primary energy source, its combustion temperature in the gas turbine combustion chamber can reach over 1000℃, which is considered high-grade thermal energy. However, in a simple cycle gas-fired power generation process, the high-temperature gas is only used for a single power generation operation before being discharged, with a power generation efficiency typically only 30%–40%. A large amount of medium-grade waste heat (400–600℃) carried in the flue gas is wasted without being utilized. Meanwhile, the driving heat source temperature required for an absorption refrigeration cycle is approximately 100–200℃, and the heating temperature required for distillation-based seawater desalination is also within this low-to-medium grade range. The heat demand from these two components and the waste heat from the gas turbine flue gas have good temperature and grade matching, but current technology does not couple these three components step-by-step along the path of "high-temperature power generation → medium-temperature waste heat driving refrigeration and desalination." This results in the same primary energy input only being able to complete a single power generation function, wasting the remaining heat, and requiring separate consumption of high-grade electrical energy or other primary energy sources for refrigeration and desalination, leading to low overall energy utilization efficiency.

[0005] The aforementioned fundamental problems further lead to redundancy in system components—power generation, cooling, and desalination are each configured independently, resulting in large equipment investments and land areas; and rigid output allocation—cooling capacity and freshwater production are adjusted independently, making it impossible to flexibly switch between the two according to real-time user needs.

[0006] Therefore, there is an urgent need for a highly efficient integrated system that can use natural gas as the sole primary energy input and organically couple power generation, cooling, and seawater desalination through energy cascade utilization to achieve combined cooling, power, and water supply. Summary of the Invention

[0007] In order to improve the utilization rate of primary energy in the overall system, this application provides a combined cooling and power coupled seawater desalination system.

[0008] The technical solution of the combined cooling and power (CCHP) coupled seawater desalination system provided in this application is as follows: A combined cooling, heating, and power (CCHP) coupled seawater desalination system includes: Gas turbines use natural gas as fuel to drive generators to produce electricity; The seawater vaporization device uses the flue gas discharged from the gas turbine to heat seawater and generate superheated steam; The waste heat absorption chiller unit uses the superheated steam as the driving heat source to produce cooling capacity; An ice maker uses the cooling capacity generated by the waste heat absorption refrigeration unit to freeze seawater into ice. An ice storage tank stores the ice produced by the ice maker. The ice storage tank is connected to the user's cooling equipment through a refrigerant circulation pipeline. The ice melts and releases cold in the ice storage tank to cool the refrigerant and achieve cooling. The fresh water produced by the condensation of superheated steam in the waste heat absorption refrigeration unit, and the fresh water produced by the melting of ice in the ice storage tank, are used as the fresh water output of the system.

[0009] Optionally, it also includes a water storage tank for storing pretreated seawater, and the seawater in the water storage tank is respectively connected to the seawater vaporization device and the ice maker.

[0010] Optionally, it also includes a freshwater storage tank for collecting freshwater generated by the condensation of the superheated steam and freshwater generated by the melting of ice in the ice storage tank.

[0011] Optionally, the waste heat absorption chiller unit includes a generator, an absorber, a condenser, and an evaporator; The superheated steam is introduced into the generator to heat the rich solution inside, causing the rich solution to release gaseous refrigerant, while the superheated steam itself condenses into fresh water. The gaseous refrigerant enters the condenser and condenses into a liquid refrigerant. After being throttled, the liquid refrigerant enters the evaporator to evaporate and absorb heat, thereby cooling the refrigerant flowing to the ice maker. The gaseous refrigerant generated by the evaporator enters the absorber, is absorbed by the lean solution from the generator, and the resulting rich solution is sent back to the generator to complete the solution cycle.

[0012] Optionally, a GAX heat exchanger is provided between the generator and the absorber, in which the lean solution from the generator and the rich solution from the absorber exchange heat in a countercurrent manner to achieve solution reheating.

[0013] Optionally, the ice in the ice storage tank melts and releases cold to cool the refrigerant, while maintaining a low-temperature environment in the ice storage tank so that the unmelted ice can be stably preserved.

[0014] Optionally, the cooling medium of the condenser is seawater. The seawater flows through the condenser before entering the seawater vaporization device, and is preheated after absorbing the latent heat of condensation of the refrigerant.

[0015] Optionally, a subcooler is provided between the condenser and the evaporator, and the subcooler uses the melted ice water discharged from the ice storage tank to precool the liquid refrigerant.

[0016] Optionally, a GVX heat exchanger is provided between the condenser and the evaporator. The GVX heat exchanger uses the low-temperature gaseous refrigerant discharged from the evaporator to subcool the liquid refrigerant, and at the same time preheats the gaseous refrigerant before it enters the absorber.

[0017] Optionally, the cooling medium of the absorber is seawater. The seawater flows through the absorber before entering the seawater vaporization device, and is preheated after absorbing the heat of absorption released by the gaseous refrigerant in the lean solution.

[0018] Optionally, it also includes a freshwater heat exchanger, through which the freshwater discharged from the generator flows before being discharged to the outside, preheating the seawater flowing through the freshwater heat exchanger.

[0019] Optionally, it also includes a flue gas heat exchanger, located on the flue gas outlet side of the seawater vaporization device; the flue gas discharged from the seawater vaporization device first flows through the flue gas heat exchanger to preheat the seawater flowing through the flue gas heat exchanger before being discharged.

[0020] Optionally, a precooler is also included, located on the pipeline from the water storage tank to the ice maker; the fresh water formed by the melting of ice in the ice storage tank is introduced into the tube side of the precooler to precool the seawater flowing to the ice maker in the shell side.

[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. Using natural gas as a primary energy source, electricity, steam, cooling and fresh water are produced sequentially. The energy of each grade is utilized step by step along the temperature decrease path. The comprehensive utilization rate of primary energy is much higher than that of conventional schemes that separately supply power, cooling and desalination. 2. Superheated steam serves as both the heating medium driving the absorption refrigeration cycle and a product of distillation desalination; ice serves as both an intermediate product of cryogenic desalination and an energy storage medium for cooling. After completing their respective heat or cold energy transfer functions, both steam and ice are ultimately converted into freshwater. 3. The temperature of the seawater in the condenser tubes rises after absorbing the latent heat of condensation of the gaseous refrigerant. When the preheated seawater enters the seawater vaporization device, the required amount of flue gas heating is reduced accordingly, which reduces the heat load of the seawater vaporization device and the flue gas exhaust temperature. This allows more heat in the flue gas to be recovered and utilized instead of being lost with the exhaust, thus improving the utilization depth of the waste heat of the flue gas. 4. The melted ice water discharged from the ice storage tank is close to 0℃. It is then passed through the tube side of the subcooler to exchange heat with the liquid refrigerant in the shell side. This further cools the liquid refrigerant before it is throttled by the first pressure-reducing valve, increasing the subcooling of the liquid refrigerant entering the evaporator after throttling, thereby increasing the effective cooling capacity per unit mass of refrigerant in the evaporator. Simultaneously, the melted ice water's temperature rises after heat exchange, allowing it to be output as desalinated water. The cold energy recovery process does not affect the quality of the freshwater. 5. Before entering the absorber, the low-temperature gaseous refrigerant at the evaporator outlet exchanges heat with the liquid refrigerant in the tube side of the GVX heat exchanger, further subcooling the liquid refrigerant while preheating the gaseous refrigerant. This increased subcooling of the liquid refrigerant directly enhances the evaporator's cooling capacity; simultaneously, it effectively utilizes the cooling capacity of the gaseous refrigerant. Attached Figure Description

[0022] Figure 1 This is a flowchart of the system in Embodiment 1 of this application; Figure 2 This is a schematic diagram of the waste heat absorption chiller unit of Embodiment 1 of this application; Figure 3 This is a flowchart of the system in Embodiment 2 of this application; Figure 4 This is a flowchart of the system in Embodiment 3 of this application; Figure 5 This is a flowchart of the system in Embodiment 4 of this application; Figure 6 This is a flowchart of the system in Embodiment 5 of this application; Figure 7 This is a flowchart of the system in Embodiment 6 of this application; Figure 8 This is a flowchart of the system in Embodiment 7 of this application; Figure 9 This is a flowchart of the system in Embodiment 8 of this application; Figure 10 This is a flowchart of the system in Embodiment 9 of this application; Figure 11 This is a flowchart of the system in Embodiment 10 of this application.

[0023] Explanation of reference numerals in the attached figures: 01. Freshwater heat exchanger; 02. Flue gas heat exchanger; 03. Precooler; 1. Water storage tank; 11. First pipeline; 12. Second pipeline; 2. Gas turbine; 21. Flue gas pipeline; 3. Generator; 4. Seawater vaporization device; 41. Steam pipeline; 5. Waste heat absorption chiller unit; 51. Generator; 52. Absorber; 53. Condenser; 54. Evaporator; 541. Refrigerant return pipeline; 55. GAX heat exchanger; 551. Rich liquid pipeline; 552. Lean liquid pipeline; 553. Solution pump; 554. Second pressure reducing valve; 6. Ice maker; 61. First circulation pipeline; 7. Ice storage tank; 71. Second circulation pipeline; 8. Freshwater storage tank; 81. First freshwater pipeline; 82. Second freshwater pipeline; 9. Subcooler; 10. GVX heat exchanger. Detailed Implementation

[0024] The following is in conjunction with the appendix Figure 1-11 This application will be described in further detail. Example 1

[0025] Reference Figure 1-2 This embodiment provides a combined cooling and power (CCHP) coupled seawater desalination system, including a water storage tank 1, a gas turbine 2, a generator 3, a seawater vaporization device 4, a waste heat absorption chiller 5, an ice maker 6, and an ice storage tank 7.

[0026] After pretreatment, the seawater enters the storage tank 1. The seawater in the storage tank 1 is connected to the shell inlet of the seawater vaporization device 4 through the first pipeline 11 and to the ice maker 6 through the second pipeline 12.

[0027] Natural gas is fed into the combustion chamber of gas turbine 2 through a fuel pipeline. The high-temperature and high-pressure gas generated by combustion drives the output shaft of gas turbine 2 to rotate. The output shaft is connected to the rotor of generator 3, which drives generator 3 to output electricity and feed it into the power grid.

[0028] The high-temperature flue gas discharged from the gas turbine 2 is introduced into the tube-side inlet of the seawater vaporization device 4 through the flue gas pipeline 21. The high-temperature flue gas flows in the tube side of the seawater vaporization device 4 and exchanges heat with the seawater in the shell side through the heat exchange tube wall, heating and evaporating the seawater. After absorbing the heat of the flue gas in the shell side, the seawater boils and generates superheated steam. The superheated steam is discharged from the shell-side steam outlet of the seawater vaporization device 4 and transported to the waste heat absorption chiller unit 5 through the steam pipeline 41. The cooled flue gas is discharged from the seawater vaporization device.

[0029] A first circulation pipe 61 is provided between the waste heat absorption chiller unit 5 and the ice maker 6. The waste heat absorption chiller unit 5 cools down the first refrigerant. After cooling, the first refrigerant enters the tube inlet of the ice maker 6 through the first circulation pipe 61. It flows in the tubes of the ice maker 6 and exchanges heat with the seawater in the ice maker 6 through the heat exchange tube walls. It absorbs the heat from the seawater, causing the temperature of the seawater in the ice maker 6 to drop and gradually freeze into ice. The solution precipitated during the freezing process is brine. After the heat exchange and temperature rise, the first refrigerant returns to the waste heat absorption chiller unit 5 from the tube outlet through the first circulation pipe 61, completing the first refrigerant cycle.

[0030] The ice produced by the ice maker 6 is transported to the ice storage tank 7 for storage. The user's refrigeration equipment is connected to the ice storage tank 7 through the second circulation pipe 71. The second refrigerant flows in the second circulation pipe 71 and exchanges heat with the ice-water mixture in the ice storage tank 7 through the coil wall. The melting ice absorbs the heat of the second refrigerant and at the same time absorbs the heat of the ice in the ice storage tank 7. After the temperature of the second refrigerant drops, it returns to the user's refrigeration equipment through the second circulation pipe 71. The fan coil units and other terminal devices in the user's refrigeration equipment exchange heat with the indoor air with the cooled second refrigerant and blow out cold air to achieve cooling. As the ice melts, the ice storage tank 7 absorbs heat from the surroundings, so that the unmelted ice in the ice storage tank 7 is stably preserved.

[0031] Fresh water produced by the melting of ice in ice storage tank 7 flows to fresh water storage tank 8 via the first fresh water pipeline 81. Fresh water produced by the release and condensation of superheated steam in waste heat absorption refrigeration unit 5 flows to fresh water storage tank 8 via the second fresh water pipeline 82.

[0032] This embodiment uses natural gas as the primary energy source, producing electricity, steam, cooling and fresh water in sequence. The energy of each grade is utilized step by step along the temperature decrease path, and the comprehensive utilization rate of primary energy is much higher than that of conventional schemes that separately supply power, cooling and desalination.

[0033] Superheated steam serves as both the heating medium driving the absorption refrigeration cycle and a product of distillation desalination; ice serves as both an intermediate product of cryogenic desalination and an energy storage medium for cooling. After completing their respective heat or cold energy transfer functions, steam and ice are ultimately converted into freshwater, significantly reducing system components and intermediate steps.

[0034] Ice storage tank 7 has both cold storage and fresh water storage functions. During peak electricity or cooling periods, ice can be used for cooling release first. During periods of urgent fresh water demand, the melting speed of ice can be accelerated to increase fresh water production, thus achieving flexible allocation of both cold and water outputs.

[0035] The waste heat absorption chiller unit 5 includes a generator 51, an absorber 52, a condenser 53, an evaporator 54, and a GAX heat exchanger 55.

[0036] Superheated steam enters the tube-side inlet of generator 51 through steam pipe 41, flows within the tube side, and exchanges heat with the rich solution in the shell side through the heat exchange tube walls. The superheated steam releases heat and condenses into fresh water, which is discharged from the tube-side outlet and flows to the fresh water storage tank 8 via the second fresh water pipe 82. The rich solution in the shell side absorbs the latent heat of condensation of the superheated steam and rises in temperature, releasing gaseous refrigerant. The gaseous refrigerant is discharged from the top of the shell side of generator 51 and flows to condenser 53 via refrigerant vapor pipe. The lean solution in the shell side of generator 51, after being decomposed, is drawn out from the bottom of the shell side and enters the tube-side inlet of GAX heat exchanger 55 via lean solution pipe 552. After exchanging heat with the rich solution from absorber 52 in the shell side and cooling down, it enters absorber 52 from the tube-side outlet.

[0037] Gaseous refrigerant from generator 51 enters the shell side of condenser 53, and circulating cooling water enters the tube side of condenser 53 from the tube side inlet. The gaseous refrigerant exchanges heat with the circulating cooling water in the tube side through the heat exchange tube wall and condenses into liquid refrigerant. The liquid refrigerant is discharged from the bottom of the shell side of condenser 53, and after being throttled and expanded by the first pressure reducing valve, it enters evaporator 54.

[0038] Liquid refrigerant enters the shell side of evaporator 54 and evaporates and absorbs heat within it. The first secondary refrigerant enters the tube side of evaporator 54 from the tube side inlet, flows within the tube side, and exchanges heat with the evaporating refrigerant in the shell side through the heat exchange tube walls. The refrigerant's evaporation and heat absorption cool the first secondary refrigerant in the tube side. The cooled first secondary refrigerant then flows back to the ice maker 6 from the tube side outlet via a pipeline. The gaseous refrigerant produced by evaporation within the shell side of evaporator 54 is discharged from the top of the shell side and flows to the absorber 52 via the refrigerant return gas pipeline 541.

[0039] Gaseous refrigerant from evaporator 54 enters the shell side of absorber 52, and lean solution from GAX heat exchanger 55 enters the shell side of absorber 52. The lean solution sprays and absorbs the gaseous refrigerant within the shell side. The heat released during absorption is carried away by circulating cooling water in the tube side, which enters from the tube side inlet and exits from the tube side outlet of absorber 52. The rich solution formed after absorbing the gaseous refrigerant in the shell side of absorber 52 is drawn from the bottom of the shell side and enters the shell side inlet of GAX heat exchanger 55 via rich solution line 551. It flows within the shell side, exchanges heat with the lean solution from generator 51 in the tube side, and then enters generator 51 from the shell side outlet, completing the solution circulation. A solution pump 553 is installed on rich solution line 551 to transport the rich solution from absorber 52 to generator 51; a second pressure reducing valve 554 is installed on lean solution line 552.

[0040] The lean solution from generator 51 flows through the tube side of GAX heat exchanger 55, while the rich solution from absorber 52 flows through the shell side of GAX heat exchanger 55. The two solutions exchange heat in countercurrent through the heat exchange tube walls to achieve solution reheating.

[0041] This embodiment uses natural gas as the sole primary energy input, achieving combined cooling, electricity, and water supply through energy cascade utilization. Specifically, natural gas is burned in gas turbine 2 to produce high-temperature gas exceeding approximately 1000°C. This gas first drives the output shaft of gas turbine 2 to generate electricity, which is the first stage of energy utilization (high-grade heat energy → electricity). The flue gas discharged from gas turbine 2 still has a temperature as high as 400-600°C. This medium-grade flue gas waste heat is passed into seawater vaporization device 4 to heat seawater, generating superheated steam, which is the second stage of energy utilization (medium-grade flue gas waste heat → steam heat energy). The superheated steam enters the generator 51 of the absorption chiller unit, serving as a driving heat source to desorb refrigerant vapor from the rich solution, driving the refrigeration cycle to output cooling capacity, which is the third stage of energy utilization (steam heat energy → cooling energy). Cold energy is transferred to the ice maker 6 via the first refrigerant, causing seawater to freeze and crystallize into ice. The ice is stored in the ice storage tank 7 and then circulated to supply cooling to users via the second refrigerant. This is the fourth stage of energy utilization (cold energy → ice storage → cooling supply). In this energy ladder chain, superheated steam releases heat in the generator 51 and then condenses into fresh water. Ice melts in the ice storage tank 7 after releasing heat and also becomes fresh water. The two streams of fresh water are then recycled to the fresh water storage tank 8.

[0042] The working process of this embodiment is as follows: Natural gas is burned in the gas turbine 2 to generate electricity and connect to the grid. The high-temperature flue gas discharged from the gas turbine 2 flows in the tube side of the seawater vaporization device 4, heating the seawater in the shell side to generate superheated steam. The superheated steam enters the tube side of the generator 51 of the waste heat absorption chiller unit 5, heating the rich solution in the shell side and driving the absorption refrigeration cycle. In the evaporator 54, the shell side refrigerant evaporates to cool the first refrigerant in the tube side. The cooled first refrigerant is passed into the tube side of the ice maker 6, where it exchanges heat with the seawater in the shell side, causing the seawater to freeze into ice. The ice is transported to the ice storage tank 7. The second refrigerant for the user's cooling equipment flows through the submerged heat exchange coil in the ice storage tank 7, exchanges heat with the ice-water mixture in the tank, and is cooled. It is then returned to the user's terminal to blow out cold air to provide cooling. The fresh water produced by the melting ice and the fresh water produced by the condensation of superheated steam are both collected in the fresh water storage tank 8, realizing the combined cooling, electricity, and water supply. Example 2

[0043] Reference Figure 3 This embodiment provides another combined cooling and power (CCHP) coupled seawater desalination system. The difference from Embodiment 1 is that a subcooler 9 is added between the shell-side outlet of condenser 53 and the shell-side inlet of evaporator 54.

[0044] The liquid refrigerant flowing out of the shell side of condenser 53 enters the shell side of subcooler 9. The fresh water generated by the melting of ice in ice storage pool 7 is introduced into the tube side inlet of subcooler 9 through a pipeline. It flows in the tube side and exchanges heat with the liquid refrigerant in the shell side through the heat exchange tube wall. After absorbing the heat of the liquid refrigerant, the fresh water is discharged from the tube side outlet. The liquid refrigerant is further cooled in the shell side.

[0045] The melted ice water discharged from ice storage tank 7 is close to 0°C. It is then passed through the tube side of subcooler 9 to exchange heat with the liquid refrigerant in the shell side. This further cools the liquid refrigerant before it is throttled by the first pressure-reducing valve, increasing the subcooling of the liquid refrigerant entering evaporator 54 after throttling. This, in turn, increases the effective cooling capacity per unit mass of refrigerant in evaporator 54. Simultaneously, the melted ice water's temperature rises after heat exchange, making it suitable for use as desalination product water. The cold energy recovery process does not affect the quality of the desalinated water. Example 3

[0046] Reference Figure 4 This embodiment provides another combined cooling and power (CCHP) coupled seawater desalination system. The difference from Embodiment 1 is that a GVX (Gas-Vapor heat exchanger) is added between the shell-side outlet of condenser 53 and the shell-side inlet of evaporator 54.

[0047] The liquid refrigerant, cooled by the condenser 53, enters the tube-side inlet of the GVX heat exchanger 10 through a pipeline and flows within the tube side of the GVX heat exchanger 10. Low-temperature gaseous refrigerant from the top of the shell side of the evaporator 54 is introduced into the shell side of the GVX heat exchanger 10. The liquid refrigerant in the tube side and the low-temperature gaseous refrigerant in the shell side exchange heat through the heat exchange tube walls. After being further subcooled in the tube side, the liquid refrigerant exits from the tube-side outlet and enters the shell side of the evaporator 54. The gaseous refrigerant generated by evaporation in the evaporator 54 exits from the top of the shell side and first enters the shell side of the GVX heat exchanger 10, where it exchanges heat with the liquid refrigerant in the tube side and is heated before entering the shell side of the absorber 52.

[0048] Before entering the absorber 52, the low-temperature gaseous refrigerant at the outlet of evaporator 54 exchanges heat with the liquid refrigerant in the tube side of the GVX heat exchanger 10, further subcooling the liquid refrigerant while preheating the gaseous refrigerant. This increased subcooling of the liquid refrigerant directly enhances the cooling capacity of evaporator 54; simultaneously, it effectively recovers and utilizes the cooling capacity of the gaseous refrigerant. Example 4

[0049] Reference Figure 5 This embodiment provides another combined cooling and power (CCHP) coupled seawater desalination system. The difference from Embodiment 1 is that a subcooler 9 and a GVX heat exchanger 10 are added between the shell-side outlet of condenser 53 and the shell-side inlet of evaporator 54.

[0050] The liquid refrigerant flowing out of the shell side of condenser 53 enters the shell side of subcooler 9. The fresh water generated by the melting of ice in ice storage pool 7 is introduced into the tube side inlet of subcooler 9 through a pipeline. It flows in the tube side and exchanges heat with the liquid refrigerant in the shell side through the heat exchange tube wall. After absorbing the heat of the liquid refrigerant, the fresh water is discharged from the tube side outlet. The liquid refrigerant is further cooled in the shell side.

[0051] The liquid refrigerant, cooled by cooler 9, enters the tube-side inlet of GVX heat exchanger 10 through pipes and flows within the tube side of GVX heat exchanger 10. Low-temperature gaseous refrigerant from the top of the shell side of evaporator 54 is introduced into the shell side of GVX heat exchanger 10. The liquid refrigerant in the tube side exchanges heat with the low-temperature gaseous refrigerant in the shell side through the heat exchange tube walls. After being further subcooled in the tube side, the liquid refrigerant exits from the tube-side outlet and enters the shell side of evaporator 54. The gaseous refrigerant produced by evaporation in evaporator 54 exits from the top of the shell side, first entering the shell side of GVX heat exchanger 10, where it exchanges heat with the liquid refrigerant in the tube side and rises in temperature before entering the shell side of absorber 52.

[0052] The synergistic effect of subcooler 9 and GVX heat exchanger 10 allows the liquid refrigerant to undergo two subcooling processes: ice melt water cooling recovery and low-temperature gaseous refrigerant at the outlet of evaporator 54. This results in maximum subcooling before entering evaporator 54, significantly improving the effective cooling capacity and coefficient of performance (COP) of evaporator 54. Example 5

[0053] Reference Figure 6 This embodiment provides another combined cooling and power coupled seawater desalination system. The difference from embodiment 1 is that the cooling medium of the tube side of the condenser 53 is replaced by seawater instead of circulating cooling water. The seawater in the reservoir 1 flows through the tube side of the condenser 53 before entering the seawater vaporization device 4, serving as the cooling medium of the condenser 53.

[0054] Seawater from reservoir 1 enters the tube-side inlet of condenser 53 via the first pipe 11. It flows within the tube side of condenser 53, exchanging heat with the gaseous refrigerant in the shell side through the heat exchange tube walls, carrying away the latent heat of condensation of the refrigerant. After being preheated, it exits from the tube-side outlet and enters the shell side of seawater vaporization device 4. The condensed and liquefied liquid refrigerant in the shell side of condenser 53 exits from the bottom of the shell side and enters evaporator 54.

[0055] After the seawater in the tube side of condenser 53 absorbs the latent heat of condensation of gaseous refrigerant, its temperature rises. When the preheated seawater enters the seawater vaporization device 4, the required amount of flue gas heating is reduced accordingly, which reduces the heat load of the seawater vaporization device 4 and the flue gas exhaust temperature. This allows more heat in the flue gas to be recovered and utilized instead of being lost with the exhaust, thus improving the utilization depth of the waste heat of the flue gas. Example 6

[0056] Reference Figure 7 This embodiment provides another combined cooling and power (CCHP) coupled seawater desalination system. The difference from embodiment 5 is that a subcooler 9 is added between the shell-side outlet of condenser 53 and the shell-side inlet of evaporator 54.

[0057] The liquid refrigerant flowing out of the shell side of condenser 53 enters the shell side of subcooler 9. The fresh water generated by the melting of ice in ice storage pool 7 is introduced into the tube side inlet of subcooler 9 through a pipeline. It flows in the tube side and exchanges heat with the liquid refrigerant in the shell side through the heat exchange tube wall. After absorbing the heat of the liquid refrigerant, the fresh water is discharged from the tube side outlet. The liquid refrigerant is further cooled in the shell side.

[0058] Based on the preheating of seawater feed by condensation heat recovery, the system also incorporates the recovery of ice melt water cooling capacity to precool liquid refrigerant, thereby improving system energy efficiency from both the heat source and cold source sides. Example 7

[0059] Reference Figure 8 This embodiment provides another combined cooling and power (CCHP) coupled seawater desalination system. The difference from embodiment 5 is that a GVX heat exchanger 10 is added between the shell-side outlet of condenser 53 and the shell-side inlet of evaporator 54.

[0060] The liquid refrigerant, cooled by the condenser 53, enters the tube-side inlet of the GVX heat exchanger 10 through a pipeline and flows within the tube side of the GVX heat exchanger 10. Low-temperature gaseous refrigerant from the top of the shell side of the evaporator 54 is introduced into the shell side of the GVX heat exchanger 10. The liquid refrigerant in the tube side and the low-temperature gaseous refrigerant in the shell side exchange heat through the heat exchange tube walls. After being further subcooled in the tube side, the liquid refrigerant exits from the tube-side outlet and enters the shell side of the evaporator 54. The gaseous refrigerant generated by evaporation in the evaporator 54 exits from the top of the shell side and first enters the shell side of the GVX heat exchanger 10, where it exchanges heat with the liquid refrigerant in the tube side and is heated before entering the shell side of the absorber 52.

[0061] Based on the preheating of seawater feed through condensation heat recovery, the GVX internal reheating further subcools the liquid refrigerant, thereby improving the refrigeration cycle performance from two dimensions: external heat recovery and internal cold recovery. Example 8

[0062] Reference Figure 9 This embodiment provides another combined cooling and power (CCHP) coupled seawater desalination system. The difference from embodiment 5 is that a subcooler 9 and a GVX heat exchanger 10 are added between the shell-side outlet of condenser 53 and the shell-side inlet of evaporator 54.

[0063] The liquid refrigerant flowing out of the shell side of condenser 53 enters the shell side of subcooler 9. The fresh water generated by the melting of ice in ice storage pool 7 is introduced into the tube side inlet of subcooler 9 through a pipeline. It flows in the tube side and exchanges heat with the liquid refrigerant in the shell side through the heat exchange tube wall. After absorbing the heat of the liquid refrigerant, the fresh water is discharged from the tube side outlet. The liquid refrigerant is further cooled in the shell side.

[0064] The liquid refrigerant, cooled by cooler 9, enters the tube-side inlet of GVX heat exchanger 10 through pipes and flows within the tube side of GVX heat exchanger 10. Low-temperature gaseous refrigerant from the top of the shell side of evaporator 54 is introduced into the shell side of GVX heat exchanger 10. The liquid refrigerant in the tube side exchanges heat with the low-temperature gaseous refrigerant in the shell side through the heat exchange tube walls. After being further subcooled in the tube side, the liquid refrigerant exits from the tube-side outlet and enters the shell side of evaporator 54. The gaseous refrigerant produced by evaporation in evaporator 54 exits from the top of the shell side, first entering the shell side of GVX heat exchanger 10, where it exchanges heat with the liquid refrigerant in the tube side and rises in temperature before entering the shell side of absorber 52.

[0065] The process optimization principle of this embodiment based on Embodiment 1 is as follows: First, seawater replaces circulating cooling water as the cooling medium for condenser 53. The seawater in the tube side of condenser 53 absorbs the latent heat of condensation of the gaseous refrigerant, increasing its temperature. When the preheated seawater enters the seawater vaporization device 4, the required amount of flue gas heating is reduced accordingly, lowering the heat load of the seawater vaporization device 4 and the flue gas exhaust temperature, thus improving the utilization depth of the flue gas waste heat.

[0066] Secondly, a subcooler 9 is added to recover the cooling capacity of the melted ice water. The melted ice water discharged from the ice storage tank 7 is close to 0°C. It is passed into the tube side of the subcooler 9 to exchange heat with the liquid refrigerant in the shell side. This further cools the liquid refrigerant before it is throttled by the first pressure reducing valve, increasing the subcooling degree of the liquid refrigerant entering the evaporator 54 after throttling, thereby increasing the effective cooling capacity per unit mass of refrigerant in the evaporator 54. At the same time, the temperature of the melted ice water rises after heat exchange, and it can be output as desalinated finished water. The cooling capacity recovery process does not affect the quality of the freshwater.

[0067] Third, a GVX heat exchanger 10 is added to achieve internal heat regeneration within the refrigeration cycle. Before entering the absorber 52, the low-temperature gaseous refrigerant at the outlet of evaporator 54 exchanges heat with the liquid refrigerant in the tube side of the GVX heat exchanger 10, further subcooling the liquid refrigerant while preheating the gaseous refrigerant. This increased subcooling of the liquid refrigerant directly improves the cooling capacity of evaporator 54; simultaneously, it effectively utilizes the cooling capacity of the gaseous refrigerant.

[0068] The three optimization measures mentioned above work together to achieve a systematic improvement in the coefficient of performance (COP) of the refrigeration cycle: condensation heat recovery preheats the seawater feed, ice melt water cooling recovery reduces the enthalpy of the liquid refrigerant before it enters the evaporator 54, and internal reheating in the GVX further subcools the liquid refrigerant. All three measures increase the ratio of the effective cooling capacity of the evaporator 54 to the total input energy of the system at different stages.

[0069] The working process of this embodiment is as follows: Natural gas is burned in the gas turbine 2 to generate electricity and connect to the grid. The high-temperature flue gas discharged from the gas turbine 2 heats the seawater in the shell side of the seawater vaporization device 4 to produce superheated steam, which drives the absorption refrigeration cycle. The seawater in the reservoir 1 first flows through the tube side of the condenser 53, serving as a cooling medium to carry away the latent heat of condensation of the refrigerant. After being preheated, it enters the seawater vaporization device 4. The liquid refrigerant discharged from the condenser 53 flows sequentially through the shell side of the subcooler 9 and the tube side of the GVX heat exchanger 10. In the subcooler 9, it is precooled by the low-temperature melted ice water discharged from the ice storage tank 7. In the GVX heat exchanger 10, it is further subcooled by the low-temperature gaseous refrigerant at the outlet of the evaporator 54. Then, it enters the evaporator 54 through throttling, where it cools the first refrigerant by absorbing heat through evaporation. The cooled first refrigerant freezes the seawater into ice in the ice maker 6, and the ice is transported to the ice storage tank 7. The ice-water mixture in ice storage tank 7 cools the second refrigerant to provide cooling for users; part of the melted ice water is produced as fresh water, and the other part is fed into subcooler 9 to recover cooling capacity. The fresh water produced by the condensation of superheated steam and the fresh water produced by the melting of ice are both collected in fresh water storage tank 8. Example 9

[0070] Reference Figure 10 This embodiment provides another combined cooling and power coupled seawater desalination system. The difference from embodiment 8 is that the cooling medium for the tube side of the absorber 52 is replaced by seawater instead of circulating cooling water. Before entering the seawater vaporization device 4, part of the seawater in the reservoir 1 flows through the tube side of the absorber 52 as the cooling medium for the absorber 52. A freshwater heat exchanger 01 and a flue gas heat exchanger 02 are added between the tube side outlet of the absorber 52 and the shell side inlet of the seawater vaporization device 4.

[0071] Seawater in reservoir 1 enters the tube-side inlet of condenser 53 via the first pipe 11, and the other part enters the tube-side inlet of absorber 52. It flows in the tube-side of absorber 52 and exchanges heat with the rich solution in the shell side through the heat exchange tube wall. It carries away the heat released by the gaseous refrigerant absorbed by the lean solution. After being preheated, it is discharged from the tube-side outlet and enters the tube-side of freshwater heat exchanger 01.

[0072] Before entering the freshwater storage tank 8, the freshwater discharged from the tube side outlet of generator 51 first enters through the shell side inlet of freshwater heat exchanger 01, and then exits through the shell side outlet of freshwater heat exchanger 01 and flows to freshwater storage tank 8. The seawater in the tube side of freshwater heat exchanger 01 flows and exchanges heat with the freshwater in the shell side of freshwater heat exchanger 01. After the freshwater cools down, it enters the freshwater storage tank 8, and after the seawater warms up, it flows to the tube side of flue gas heat exchanger 02.

[0073] The flue gas discharged from the tube side outlet of the seawater vaporization device 4 first enters from the shell side inlet of the flue gas heat exchanger 02, and then exits from the shell side outlet of the flue gas heat exchanger 02. The seawater in the tube side of the flue gas heat exchanger 02 flows and exchanges heat with the flue gas in the shell side of the flue gas heat exchanger 02. After the flue gas cools down, it is discharged to the outside. After the seawater heats up, it flows to the shell side inlet of the seawater vaporization device 4. Example 10

[0074] Reference Figure 11 This embodiment provides another combined cooling and power coupled seawater desalination system. The difference from embodiment 2 is that: before flowing from the water storage tank 1 to the ice maker 6 through the second pipeline 12, the water first flows into the shell-side inlet of the precooler 03, and then the ice is discharged from the shell-side outlet of the precooler 03 to flow to the ice maker 6.

[0075] The ice in the ice storage tank 7 melts to form fresh water. Part of it flows to the tube inlet of the subcooler 9, and the other part flows to the tube inlet of the precooler 03. The fresh water flows in the tube side of the precooler 03 and exchanges heat with the seawater in the shell side through the heat exchange tube wall. After the fresh water is heated, it is discharged to the fresh water storage tank 8 through the tube outlet of the precooler 03. After the seawater is cooled, it flows to the ice maker 6 through the shell outlet of the precooler 03.

[0076] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A combined cooling and power (CCHP) coupled seawater desalination system, characterized in that, include: The gas turbine (2) uses natural gas as fuel to drive the generator (3) to generate electricity; The seawater vaporization device (4) uses the flue gas discharged from the gas turbine (2) to heat the seawater and generate superheated steam; Waste heat absorption chiller (5) uses the superheated steam as the driving heat source to produce cooling capacity; An ice maker (6) uses the cooling capacity generated by the waste heat absorption refrigeration unit (5) to freeze seawater into ice. Ice storage tank (7) stores the ice produced by the ice maker (6). The ice storage tank (7) is connected to the user's cooling equipment through a refrigerant circulation pipeline. The ice melts and releases cold in the ice storage tank (7) to cool the refrigerant and achieve cooling. The fresh water produced by the condensation of the superheated steam in the waste heat absorption refrigeration unit (5) and the fresh water produced by the melting of ice in the ice storage tank (7) are used as the fresh water output of the system.

2. The combined cooling and power (CCHP) seawater desalination system according to claim 1, characterized in that, It also includes a water storage tank (1) for storing pretreated seawater, and the seawater in the water storage tank (1) is respectively connected to the seawater vaporization device (4) and the ice maker (6).

3. The combined cooling and power (CCHP) seawater desalination system according to claim 1, characterized in that, It also includes a freshwater storage tank (8), which is used to collect freshwater generated by the condensation of the superheated steam and freshwater generated by the melting of ice in the ice storage tank (7).

4. The combined cooling and power (CCHP) seawater desalination system according to claim 1, characterized in that, The waste heat absorption chiller unit (5) includes a generator (51), an absorber (52), a condenser (53), and an evaporator (54); The superheated steam is introduced into the generator (51) to heat the rich solution inside, causing the rich solution to release gaseous refrigerant, while the superheated steam itself condenses into fresh water. The gaseous refrigerant enters the condenser (53) and condenses into liquid refrigerant. After being throttled, the liquid refrigerant enters the evaporator (54) to evaporate and absorb heat, thereby cooling the refrigerant flowing to the ice maker (6). The gaseous refrigerant generated by the evaporator (54) enters the absorber (52) and is absorbed by the lean solution from the generator (51). The resulting rich solution is sent back to the generator (51) to complete the solution cycle.

5. The combined cooling and power (CCHP) seawater desalination system according to claim 4, characterized in that, A GAX heat exchanger (55) is provided between the generator (51) and the absorber (52). The lean solution from the generator (51) and the rich solution from the absorber (52) exchange heat in countercurrent within the GAX heat exchanger (55) to achieve solution reheating.

6. The combined cooling and power (CCHP) seawater desalination system according to claim 1, characterized in that, The ice in the ice storage tank (7) melts and releases cold to cool the refrigerant, while maintaining a low-temperature environment in the ice storage tank (7) so that the unmelted ice can be stably preserved.

7. The combined cooling and power (CCHP) seawater desalination system according to claim 4, characterized in that, The cooling medium of the condenser (53) is seawater. Before entering the seawater vaporization device (4), the seawater flows through the condenser (53) and is preheated after absorbing the latent heat of condensation of the refrigerant.

8. The combined cooling and power (CCHP) seawater desalination system according to claim 4, characterized in that, A subcooler (9) is provided between the condenser (53) and the evaporator (54), and the subcooler (9) uses the melted ice water discharged from the ice storage tank (7) to precool the liquid refrigerant.

9. The combined cooling and power (CCHP) seawater desalination system according to claim 4, characterized in that, A GVX heat exchanger (10) is provided between the condenser (53) and the evaporator (54). The GVX heat exchanger (10) uses the low-temperature gaseous refrigerant discharged from the evaporator (54) to subcool the liquid refrigerant, and at the same time preheats the gaseous refrigerant to enter the absorber (52).

10. The combined cooling and power (CCHP) seawater desalination system according to claim 7, characterized in that, The cooling medium of the absorber (52) is seawater. Before entering the seawater vaporization device (4), part of the seawater flows through the absorber (52) and is preheated after absorbing the heat of absorption released by the gaseous refrigerant by the lean solution.

11. The combined cooling and power (CCHP) seawater desalination system according to claim 10, characterized in that, It also includes a freshwater heat exchanger (01), through which the freshwater discharged from the generator (51) flows before being discharged to the outside, preheating the seawater flowing through the freshwater heat exchanger (01).

12. The combined cooling and power (CCHP) coupled seawater desalination system according to claim 11, characterized in that, It also includes a flue gas heat exchanger (02), which is located on the flue gas outlet side of the seawater vaporization device (4); the flue gas discharged from the seawater vaporization device (4) first flows through the flue gas heat exchanger (02) to preheat the seawater flowing through the flue gas heat exchanger (02) before being discharged.

13. The combined cooling and power (CCHP) coupled seawater desalination system according to claim 2, characterized in that, It also includes a precooler (03), which is installed on the pipeline from the water storage tank (1) to the ice maker (6); the fresh water formed by the melting of ice in the ice storage tank (7) is introduced into the tube side of the precooler (03) to precool the seawater flowing to the ice maker (6) in the shell side.

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