A trigeneration system and working method based on deep recovery of waste heat from gas turbines

Abstract

The present invention discloses a trigeneration system and working method based on deep recovery of waste heat from a gas turbine. The system includes a gas power generation part, a supercritical carbon dioxide cycle power generation part, a heating part and a seawater desalination part. The waste heat from the gas turbine is deeply recovered according to the cascade utilization of different grades of energy to achieve the coupling integration of water supply, heat supply and power supply trigeneration. The flue gas discharged from the gas turbine first drives the supercritical carbon dioxide cycle power generation, and after cooling, it enters the waste heat boiler to heat and evaporate the circulating water. After the steam drives the absorption heat pump to provide heat, the steam is pressurized and reused through the ejector at the outlet of the seawater desalination device. The two are mixed and matched with steam as the heat source of the first effect seawater desalination device. The present invention realizes the cascade utilization of primary energy and the efficient recovery of flue gas waste heat by reasonably distributing the waste heat from the gas turbine, increases the power generation, heat supply and water supply while ensuring the normal operation of the gas turbine, and greatly improves the overall economy and energy utilization efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-generation, and in particular to a trigeneration system and working method based on deep recovery of waste heat from a gas turbine, and specifically to a water-heat-power trigeneration energy system that utilizes waste heat from a gas turbine to drive supercritical carbon dioxide cycle power generation, absorption heat pump heating, and seawater desalination. Background Art

[0002] Gas turbines are increasingly favored by the energy market due to their many advantages, such as small size, high efficiency, stable operation, fast start-up speed, and low emission levels. The exhaust temperature of gas turbines is as high as 500°C. If waste heat recovery equipment is not properly equipped, a large amount of energy will be wasted. In order to promote the further development of gas turbines, improve energy utilization, and reduce energy consumption, efficient recovery and utilization of waste heat from gas turbines is the only way. At present, waste heat boilers are mostly used to transfer heat in flue gas to water. After the water evaporates, it enters the steam turbine to expand and do work, forming a gas-steam combined cycle, and the power generation of the unit is improved. Summary of the invention

[0003] Aiming at the problem of efficient utilization of gas turbine waste heat, the present invention proposes a trigeneration system and working method based on deep recovery of gas turbine waste heat. The system includes four parts: gas power generation, supercritical carbon dioxide cycle power generation, heat supply and seawater desalination. According to the cascade utilization of different grades of energy, the gas turbine waste heat is deeply recovered to realize the coupling integration of water supply, heat supply and power supply trigeneration. The flue gas discharged by the gas turbine first heats carbon dioxide in the carbon dioxide heater, then heats the circulating water in the waste heat boiler, and is discharged after being cooled and cooled by the flue gas treatment device. The circulating water absorbs heat and evaporates in the waste heat boiler, enters the generator as a heat source to drive the water in the heat pump working fluid to evaporate, and enters the ejector after cooling to inject steam from the outlet of the fourth effect seawater desalination device. The present invention realizes the cascade utilization of energy and the efficient recovery of flue gas waste heat by reasonably distributing the waste heat of the gas turbine, increases the power generation, heat supply and water supply while ensuring the normal operation of the gas turbine, and greatly improves the overall economy and energy utilization efficiency.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A trigeneration system based on deep recovery of waste heat from a gas turbine, the system comprising a gas-fired power generation part, a supercritical carbon dioxide circulation power generation part, a heating part and a seawater desalination part; the gas-fired power generation part comprises a compressor, a combustion chamber, a gas turbine, a gas-fired generator, a flue gas treatment device and a chimney; the supercritical carbon dioxide circulation power generation part comprises a precooler, an electric motor, a carbon dioxide compressor, a carbon dioxide heater, an expander, a carbon dioxide generator and a regenerator; the heating part comprises a waste heat boiler, a solution heat exchanger, a generator, a condenser, a throttle valve, an evaporator, a working fluid pump, an absorber and a solution pump; the seawater desalination part comprises an ejector, a water spray cooling device, a first effect seawater desalination device, a second effect seawater desalination device, a third effect seawater desalination device, a fourth effect seawater desalination device, a condenser, a seawater lifting pump, a condensate pump and a condensate valve;

[0006] In the gas power generation part, the compressor, gas turbine and gas generator are coaxially connected, the compressor inlet is connected to the atmosphere, the compressor air outlet is connected to the combustion chamber inlet, the combustion chamber outlet is connected to the gas turbine inlet, the gas turbine outlet exhaust enters the carbon dioxide heater in the supercritical carbon dioxide cycle power generation part, the flue gas inlet of the flue gas treatment device is connected to the flue gas outlet of the waste heat boiler in the heating part, and the flue gas outlet of the flue gas treatment device is connected to the chimney;

[0007] In the supercritical carbon dioxide cycle power generation part, the carbon dioxide outlet of the carbon dioxide heater is connected to the inlet of the expander, the outlet of the expander is coaxially connected to the carbon dioxide generator, the carbon dioxide at the outlet of the expander releases heat in the regenerator and enters the precooler, the carbon dioxide outlet of the precooler is connected to the carbon dioxide compressor, the carbon dioxide compressor and the motor are coaxially connected, the carbon dioxide compressed in the carbon dioxide compressor enters the regenerator and is preheated by the carbon dioxide at the outlet of the expander, and then enters the carbon dioxide heater, thereby forming a supercritical carbon dioxide cycle;

[0008] In the heating part, the solution heat exchanger, generator, condenser, throttle valve, evaporator, working fluid pump, absorber and solution pump together constitute an absorption heat pump cycle; the flue gas released in the carbon dioxide heater enters the waste heat boiler, and the circulating water absorbs heat and evaporates in the waste heat boiler and serves as the heat source of the generator; the dilute solution of the heat pump working fluid flows out from the solution outlet of the absorber, enters the solution heat exchanger after being pressurized by the solution pump, enters the generator to absorb heat after preheating, and the water evaporates after heating. The formed concentrated solution enters the solution heat exchanger to exchange heat with the dilute solution, and then returns to the absorber; the water vapor evaporated in the generator enters the evaporator through the condenser and the throttle valve, and the evaporated low-pressure water vapor enters the absorber. The working fluid pump returns the unevaporated water to the evaporator in the form of a spray, and the low-temperature heat source enters the evaporator to cool down and then flows out; the hot network water enters the absorber for the first heat absorption, and then flows into the condenser for the second heat absorption. After reaching the heating temperature, it goes to the heat user for heating;

[0009] In the desalination part, the outlet heat source of the generator flows through the ejector and the water spray cooling device and then goes to the first effect desalination device, and then flows out through the condensate valve and the condensate pump after condensation; the seawater is pressurized by the seawater lifting pump, and then goes to the first effect desalination device, the second effect desalination device, the third effect desalination device, and the fourth effect desalination device for spraying after passing through the condenser; the concentrated brine of the first effect desalination device, the second effect desalination device, and the third effect desalination device flows step by step to the fourth effect desalination device and then flows out; the distilled water in the second effect desalination device and the third effect desalination device flows step by step to the fourth effect desalination device, and the water vapor distilled from the seawater flows step by step to the condenser for condensation, and the generated distilled water returns to the fourth effect desalination device and flows out.

[0010] Specifically, the heat source of the regenerator is the high-temperature carbon dioxide from the expander outlet, which releases heat and goes to the precooler to heat the circulating water; the cold source of the regenerator is the low-temperature carbon dioxide from the carbon dioxide compressor, which absorbs heat and goes to the carbon dioxide heater.

[0011] Specifically, the heat source of the carbon dioxide heater is the exhaust gas from the gas turbine, which releases heat and then goes to the waste heat boiler; the cold source of the carbon dioxide heater is the low-temperature carbon dioxide from the regenerator, which absorbs heat and then enters the expander to expand and do work.

[0012] Specifically, the heat source of the precooler is the high-temperature carbon dioxide from the regenerator, which enters the carbon dioxide compressor after exothermic cooling; the cold source of the precooler is the circulating water from the condensate pump, which enters the waste heat boiler after preheating.

[0013] Specifically, the flue gas discharged from the gas turbine outlet is first heated with carbon dioxide in a carbon dioxide heater, and then heated with circulating water in a waste heat boiler. After being cooled, it is passed through a flue gas treatment device and meets the standards before being discharged through a chimney.

[0014] Specifically, the circulating water that absorbs heat in the precooler enters the waste heat boiler to continue absorbing heat and evaporating, and enters the generator as a heat source to drive the water in the heat pump working fluid to evaporate. After cooling, it enters the ejector and draws the steam from the outlet of the fourth-effect seawater desalination device. After cooling by the mixed steam and water spray cooling device, it goes to the first-effect seawater desalination device to drive the evaporation of seawater. After the steam condenses, it returns to the precooler after the flow is controlled by the condensate valve and the pressure is increased by the condensate pump to complete the cycle.

[0015] Preferably, the regenerator, carbon dioxide heater and precooler are all arranged in countercurrent.

[0016] Preferably, the heat pump working fluid is lithium bromide solution.

[0017] The present invention has the following advantages and effects:

[0018] 1) The waste heat from the gas turbine first drives the supercritical carbon dioxide cycle to generate electricity, and then provides heat and desalination, thus realizing the cascade utilization of energy. Through the distribution of energy grades, the waste heat from the exhaust gas is deeply and efficiently recovered;

[0019] 2) By coupling the supercritical carbon dioxide cycle, the power generation is increased, while the heat and water supply are increased, which brings higher economic benefits and significantly improves the overall economic efficiency;

[0020] 3) On the basis of keeping the gas usage unchanged, the energy output is increased, which is beneficial to energy conservation and emission reduction and plays a positive role in environmental improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of a trigeneration system based on deep recovery of waste heat from gas turbines.

[0022] In the figure: I-gas power generation part; II-supercritical carbon dioxide cycle power generation part; III-heating part; IV-seawater desalination part; 1-compressor; 2-combustion chamber; 3-gas turbine; 4-gas generator; 5-flue gas treatment device; 6-chimney; 7-precooler; 8-motor; 9-carbon dioxide compressor; 10-carbon dioxide heater; 11-expander; 12-carbon dioxide generator; 13-regenerator; 14-waste heat boiler; 15-solution heat exchanger; 16-generator; 17-condenser; 18-throttle valve; 19-evaporator; 20-working fluid pump; 21-absorber; 22-solution pump; 23- ejector; 24- water spray cooling device; 25- first effect seawater desalination device; 26- second effect seawater desalination device; 27- third effect seawater desalination device; 28- fourth effect seawater desalination device; 29- condenser; 30- seawater lifting pump; 31- condensate pump; 32- condensate valve. DETAILED DESCRIPTION

[0023] The present invention proposes a trigeneration system and a working method based on deep recovery of waste heat from a gas turbine. The specific process is described below with reference to the accompanying drawings and examples.

[0024] like Figure 1 A trigeneration system based on deep recovery of waste heat from a gas turbine is shown, the system comprising a gas power generation part I, a supercritical carbon dioxide cycle power generation part II, a heating part III and a seawater desalination part IV.

[0025] After being compressed by the compressor 1, the air is burned with the gas in the combustion chamber 2, with a temperature of more than 1000°C and a pressure of 1.0-1.5MPa. The air then enters the gas turbine 3 to drive the impeller, converting the thermal energy of the fuel into mechanical energy and driving the gas generator 4 to generate electricity. The flue gas temperature discharged from the gas turbine 3 is generally 450-600°C. First, it is introduced into the carbon dioxide heater 10 to heat the carbon dioxide in the supercritical carbon dioxide cycle from 200°C at the cold source outlet of the regenerator 13 to about 400°C. The cooled flue gas enters the waste heat boiler 14 to continue to release heat, and is discharged from the chimney 6 after meeting the standards of the flue gas treatment device 5. The circulating water absorbs heat and evaporates in the waste heat boiler 14, serving as the heat source of the generator 16, maintaining the temperature of the generator 16 at about 140°C, and driving the evaporation of water in the dilute solution.

[0026] The carbon dioxide at the outlet of the carbon dioxide heater 10 enters the expander 11 to expand and do work, driving the carbon dioxide generator 12 to generate electricity. The carbon dioxide at the outlet of the expander 11 (about 300°C) releases heat in the regenerator 13 and the precooler 7 successively, and then enters the carbon dioxide compressor 9, is driven by the motor 8 to increase the pressure, and enters the carbon dioxide heater 10 after being preheated in the regenerator 13, thereby forming a supercritical carbon dioxide cycle.

[0027] The solution heat exchanger 15, the generator 16, the condenser 17, the throttle valve 18, the evaporator 19, the working fluid pump 20, the absorber 21 and the solution pump 22 together constitute an absorption heat pump cycle. When the absorption heat pump is in operation, after the dilute solution of the heat pump working fluid flows out of the absorber 21, it is first pressurized by the solution pump 22, and then enters the solution heat exchanger 15, where it absorbs the heat of the concentrated solution from the generator 16, and the concentration and pressure remain unchanged while the temperature rises, and then enters the generator 16. The heat absorbed in the generator 16 reaches the boiling point temperature, and then water vapor is generated, and the concentration of the solution increases. After the concentrated solution flows out of the generator 16, it enters the solution heat exchanger 15 to release heat to the dilute solution and cool down, and then re-enters the absorber 21 to cool down to a saturated liquid under the absorption pressure, and then starts the next solution cycle. The water vapor generated in the generator 16 enters the condenser 17, where it releases heat and condenses, and then is depressurized by the throttle valve 18 and enters the evaporator 19. In the evaporator 19, it absorbs heat from the low-temperature heat source and becomes low-pressure water vapor, which enters the absorber 21 to be absorbed. The working fluid pump 20 sprays the unevaporated water back to the evaporator 19. The hot network water enters the absorber 21 for the first heat absorption, and then flows into the condenser 17 for the second heat absorption. After reaching the heating temperature, it goes to the heat user for heating.

[0028] The outlet heat source of the generator 16 enters the ejector 23 as a driving steam source, and ejects the outlet steam of the fourth-effect seawater desalination device 28 with lower temperature and pressure. The two steams are mixed and matched in the ejector 23 to realize the pressurization and reuse of low-pressure seawater desalination steam, reducing the cold end loss. After passing through the water spray cooling device 24, it goes to the first-effect seawater desalination device 25, and after condensation, it flows to the precooler 7 through the condensate valve 32 and the condensate pump 31. The seawater is pressurized by the seawater lifting pump 30, and after being preheated in the condenser 29, it goes to the first-effect seawater desalination device 25, the second-effect seawater desalination device 26, the third-effect seawater desalination device 27, and the fourth-effect seawater desalination device 28 for spraying. The water vapor distilled from the seawater flows step by step to the condenser 29 for condensation, and the generated distilled water returns to the fourth effect seawater desalination device 28 and flows out. The distilled water in the second effect seawater desalination device 26 and the third effect seawater desalination device 27 also flows step by step to the fourth effect seawater desalination device 28 and flows out. The concentrated brine flows step by step to the fourth effect seawater desalination device 28 and then flows out.

[0029] Specifically, in the regenerator 13, the high-temperature carbon dioxide from the outlet of the expander 11 heats the low-temperature carbon dioxide from the carbon dioxide compressor 9; in the carbon dioxide heater 10, the exhaust gas from the gas turbine 3 heats the low-temperature carbon dioxide from the regenerator 13; in the precooler 7, the high-temperature carbon dioxide from the regenerator 13 heats the circulating water from the condensate pump 31. All three are preferably arranged as countercurrent heat exchange.

[0030] The present invention focuses on an energy system that uses gas turbine power generation as a supporting power source, deeply recovers exhaust waste heat, and through the cascade utilization of energy, realizes the organic combination of supercritical carbon dioxide cycle power generation, absorption heat pump heating and low-temperature multi-effect seawater desalination, forming a trigeneration of water, heat and power, promoting energy conservation and emission reduction as well as improving overall economic efficiency.

[0031] In addition, it should be noted that the shapes and names of the parts of the specific embodiments described in this specification may be different. Any equivalent or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. The technicians in the technical field of the present invention make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A trigeneration system based on deep recovery of waste heat from a gas turbine, the system comprising a gas power generation part (I), a supercritical carbon dioxide circulation power generation part (II), a heating part (III) and a seawater desalination part (IV); the gas power generation part (I) comprises a compressor (1), a combustion chamber (2), a gas turbine (3), a gas generator (4), a flue gas treatment device (5) and a chimney (6); the supercritical carbon dioxide circulation power generation part (II) comprises a precooler (7), an electric motor (8), a carbon dioxide compressor (9), a carbon dioxide heater (10), an expander (11), a carbon dioxide generator (12) and a regenerator ( 13); the heating part (III) includes a waste heat boiler (14), a solution heat exchanger (15), a generator (16), a condenser (17), a throttle valve (18), an evaporator (19), a working fluid pump (20), an absorber (21) and a solution pump (22); the seawater desalination part (IV) includes an ejector (23), a water spray cooling device (24), a first effect seawater desalination device (25), a second effect seawater desalination device (26), a third effect seawater desalination device (27), a fourth effect seawater desalination device (28), a condenser (29), a seawater lifting pump (30), a condensate pump (31) and a condensate valve (32); In the gas power generation part (I), the compressor (1), the gas turbine (3) and the gas generator (4) are coaxially connected, the inlet of the compressor (1) is connected to the atmospheric environment, the air outlet of the compressor (1) is connected to the inlet of the combustion chamber (2), the outlet of the combustion chamber (2) is connected to the inlet of the gas turbine (3), the exhaust gas at the outlet of the gas turbine (3) enters the carbon dioxide heater (10) in the supercritical carbon dioxide cycle power generation part (II), the flue gas inlet of the flue gas treatment device (5) is connected to the flue gas outlet of the waste heat boiler (14) in the heating part (III), and the flue gas outlet of the flue gas treatment device (5) is connected to the chimney (6); In the supercritical carbon dioxide cycle power generation part (II), the carbon dioxide outlet of the carbon dioxide heater (10) is connected to the inlet of the expander (11), the outlet of the expander (11) is coaxially connected to the carbon dioxide generator (12), the carbon dioxide at the outlet of the expander (11) releases heat in the regenerator (13) and then enters the precooler (7), the carbon dioxide outlet of the precooler (7) is connected to the carbon dioxide compressor (9), the carbon dioxide compressor (9) and the motor (8) are coaxially connected, the carbon dioxide compressed in the carbon dioxide compressor (9) enters the regenerator (13) and is preheated by the carbon dioxide at the outlet of the expander (11), and then enters the carbon dioxide heater (10), thereby forming a supercritical carbon dioxide cycle; In the heating part (III), the solution heat exchanger (15), the generator (16), the condenser (17), the throttle valve (18), the evaporator (19), the working fluid pump (20), the absorber (21) and the solution pump (22) together constitute an absorption heat pump cycle; the flue gas released in the carbon dioxide heater (10) enters the waste heat boiler (14), and the circulating water absorbs heat and evaporates in the waste heat boiler (14) and then serves as the heat source of the generator (16); the dilute working fluid solution of the heat pump flows out from the solution outlet of the absorber (21), is pressurized by the solution pump (22), enters the solution heat exchanger (15), is preheated, and then enters the generator (16) to absorb heat and heat up. After the water evaporates, the concentrated solution formed enters the solution heat exchanger (15) to exchange heat with the dilute solution, and then returns to the absorber (21); the water vapor evaporated in the generator (16) enters the evaporator (19) through the condenser (17) and the throttle valve (18), and the evaporated low-pressure water vapor enters the absorber (21), and the working fluid pump (20) returns the unevaporated water to the evaporator (19) in the form of a spray, and the low-temperature heat source enters the evaporator (19) and flows out after cooling; the hot network water enters the absorber (21) for the first heat absorption, and then flows into the condenser (17) for the second heat absorption, and after reaching the heating temperature, it goes to the heat user for heating; In the desalination part (IV), the outlet heat source of the generator (16) flows through the ejector (23) and the water spray cooling device (24) and then flows to the first effect desalination device (25), and then flows out through the condensate valve (32) and the condensate pump (31) after condensation; the seawater is pressurized by the seawater boost pump (30), and then flows to the first effect desalination device (25), the second effect desalination device (26), the third effect desalination device (27), and the fourth effect desalination device (28) after passing through the condenser (29). Spraying; concentrated brine from the first effect seawater desalination device (25), the second effect seawater desalination device (26), and the third effect seawater desalination device (27) flows step by step to the fourth effect seawater desalination device (28) and then flows out; distilled water from the second effect seawater desalination device (26) and the third effect seawater desalination device (27) flows step by step to the fourth effect seawater desalination device (28), and water vapor distilled from seawater flows step by step to the condenser (29) for condensation, and the generated distilled water returns to the fourth effect seawater desalination device (28) and flows out.

2. A trigeneration system based on deep recovery of waste heat from gas turbines according to claim 1, characterized in that: The heat source of the regenerator (13) is the high-temperature carbon dioxide from the outlet of the expander (11), which releases heat and then goes to the precooler (7) to heat the circulating water; the cold source of the regenerator (13) is the low-temperature carbon dioxide from the carbon dioxide compressor (9), which absorbs heat and then goes to the carbon dioxide heater (10).

3. The trigeneration system based on deep recovery of waste heat from gas turbine according to claim 1, characterized in that: The heat source of the carbon dioxide heater (10) is the exhaust gas from the gas turbine (3), which releases heat and then flows into the waste heat boiler (14); the cold source of the carbon dioxide heater (10) is the low-temperature carbon dioxide from the regenerator (13), which absorbs heat and then flows into the expander (11) to expand and perform work.

4. The trigeneration system based on deep recovery of waste heat from gas turbine according to claim 1, characterized in that: The heat source of the precooler (7) is the high-temperature carbon dioxide from the regenerator (13), which enters the carbon dioxide compressor (9) after releasing heat and cooling; the cold source of the precooler (7) is the circulating water from the condensate pump (31), which enters the waste heat boiler (14) after preheating.

5. The trigeneration system based on deep recovery of waste heat from gas turbine according to claim 1, characterized in that: The flue gas discharged from the outlet of the gas turbine (3) is first heated in a carbon dioxide heater (10) to produce carbon dioxide, then heated in a waste heat boiler (14) to produce circulating water, and then cooled and discharged through a chimney (6) after passing through a flue gas treatment device (5) to meet the standards.

6. The trigeneration system based on deep recovery of waste heat from gas turbine according to claim 1, characterized in that: The circulating water that absorbs heat in the precooler (7) enters the waste heat boiler (14) to continue absorbing heat and evaporating, and enters the generator (16) as a heat source to drive the water in the heat pump working fluid to evaporate. After cooling, it enters the ejector (23) to draw steam from the outlet of the fourth-effect seawater desalination device (28), and after cooling through the mixed steam and water spray cooling device (24), it goes to the first-effect seawater desalination device (25) to drive the evaporation of seawater. After the steam is condensed, it controls the flow rate through the condensate valve (32) and is pressurized by the condensate pump (31) before returning to the precooler (7) to complete the cycle.

7. The trigeneration system based on deep recovery of waste heat from gas turbine according to claim 1, characterized in that: The regenerator (13), the carbon dioxide heater (10) and the precooler (7) are all arranged in countercurrent.

8. The trigeneration system based on deep recovery of waste heat from gas turbine according to claim 1, characterized in that: The heat pump working fluid is lithium bromide solution.

9. A working method of a trigeneration system based on deep recovery of waste heat from a gas turbine according to any one of claims 1 to 8, characterized in that: After being compressed by the compressor (1), the air is burned with the fuel gas in the combustion chamber (2), and then enters the gas turbine (3) to drive the impeller, converting the thermal energy of the fuel into mechanical energy and driving the gas generator (4) to generate electricity; the flue gas discharged from the gas turbine (3) is first introduced into the carbon dioxide heater (10), and the carbon dioxide in the supercritical carbon dioxide cycle is heated from the cold source outlet of the regenerator (13); the cooled flue gas enters the waste heat boiler (14) to continue to release heat, and is discharged from the chimney (6) after meeting the standards through the flue gas treatment device (5); the circulating water absorbs heat and evaporates in the waste heat boiler (14), and serves as the heat source of the generator (16), maintaining the temperature of the generator (16) to drive the evaporation of water in the dilute solution; The carbon dioxide at the outlet of the carbon dioxide heater (10) enters the expander (11) to expand and do work, driving the carbon dioxide generator (12) to generate electricity. The carbon dioxide at the outlet of the expander (11) releases heat in the regenerator (13) and the precooler (7) in turn, and then enters the carbon dioxide compressor (9), where it is driven by the motor (8) to increase pressure, and then enters the carbon dioxide heater (10) after being preheated in the regenerator (13), thereby forming a supercritical carbon dioxide cycle. When the absorption heat pump is in operation, after the dilute solution of the heat pump working fluid flows out of the absorber (21), it is first pressurized by the solution pump (22), and then enters the solution heat exchanger (15), where it absorbs heat from the concentrated solution from the generator (16), and the concentration and pressure remain unchanged while the temperature rises, and then enters the generator (16); in the generator (16), it absorbs heat to reach the boiling point, thereby generating water vapor, and at the same time the concentration of the solution increases; after the concentrated solution flows out of the generator (16), it enters the solution heat exchanger (15) to release heat to the dilute solution and cool down, and then re-enters the absorber (21) to cool down to the absorption pressure. The saturated liquid is then used to start the next solution cycle; the water vapor generated in the generator (16) enters the condenser (17), where it releases heat and condenses, and then is depressurized by the throttle valve (18), enters the evaporator (19), absorbs heat from the low-temperature heat source in the evaporator (19), becomes low-pressure water vapor, and enters the absorber (21) to be absorbed; the working fluid pump (20) returns the unevaporated water to the evaporator (19) in the form of a spray; the hot network water enters the absorber (21) for the first heat absorption, and then flows into the condenser (17) for the second heat absorption, and after reaching the heating temperature, it is sent to the heat user for heating; The outlet heat source of the generator (16) is used as a driving steam source to enter the ejector (23), and the outlet steam of the fourth effect seawater desalination device (28) with lower temperature and pressure is ejected; the two steam streams are mixed and matched in the ejector (23), so as to realize the pressurization and reuse of the low-pressure seawater desalination steam, thereby reducing the cold end loss; after passing through the water spray cooling device (24), it is sent to the first effect seawater desalination device (25), and after condensation, it flows to the precooler (7) through the condensate valve (32) and the condensate pump (31); the seawater is pressurized by the seawater lifting pump (30), and after being preheated in the condenser (29), it is sent to the first effect seawater desalination device (25). The first effect seawater desalination device (25), the second effect seawater desalination device (26), the third effect seawater desalination device (27), and the fourth effect seawater desalination device (28) are sprayed; the water vapor distilled from the seawater flows step by step to the condenser (29) for condensation, and the generated distilled water returns to the fourth effect seawater desalination device (28) and flows out; the distilled water in the second effect seawater desalination device (26) and the third effect seawater desalination device (27) also flows step by step to the fourth effect seawater desalination device (28) and flows out; the concentrated brine flows step by step to the fourth effect seawater desalination device (28) and then flows out.

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