Multi-stage compression heat exchange coupled carbon dioxide trapping and sealing system and multi-stage compression heat exchange coupled carbon dioxide trapping and sealing method

Abstract

The invention belongs to the technical field of carbon capture and storage, and relates to a multi-stage compression heat exchange coupled carbon dioxide capture and storage system and method, which comprises a multi-stage compression assembly, a first heat exchanger, a high temperature generator, a carbon capture device and a low temperature generator, and the cooling circulation assembly is used for receiving the ammonia water dilute solution and the ammonia vapor from the high-temperature generator and the low-temperature generator, mixing the ammonia water dilute solution with the ammonia vapor to obtain an ammonia water concentrated solution, and feeding the ammonia water concentrated solution into the high-temperature generator and the low-temperature generator respectively for recycling. According to the invention, the flue gas can be cooled from high temperature to normal temperature, so that the carbon capture device can capture normal-temperature carbon dioxide, and the carbon dioxide can recover to normal temperature after being compressed each time, so that the carbon dioxide is cooled more completely, and the compression energy required for compressing the carbon dioxide at each stage is reduced; therefore, the energy consumption in the carbon dioxide sealing process is effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon capture and storage, and relates to a carbon dioxide capture and storage system and method coupling multi-stage compression and heat exchange. Background Art

[0002] With the rapid development of industry and economy, carbon dioxide emissions have become one of the main causes of global climate change. And carbon capture and storage (CCS) technology is an important means to reduce carbon dioxide emissions. At present, power generation methods using fossil fuels such as thermal power and gas turbines will generate a large amount of greenhouse gases, so they become key application fields of CCS technology. In the capture stage, methods such as chemical absorption, physical adsorption, and membrane separation are often used to separate carbon dioxide from the flue gas; while in the storage stage, to ensure the long-term stable storage of carbon dioxide underground, it must be gradually compressed from a near-atmospheric pressure state to a super-high pressure state, so that carbon dioxide is converted into a liquid or supercritical state, thereby greatly increasing the storage density.

[0003] At present, in the traditional carbon dioxide storage process, multi-stage compression and inter-stage cooling are key steps to realize the transformation of carbon dioxide from atmospheric pressure to super-high pressure. However, since the carbon dioxide captured from the flue gas of the gas turbine has a high temperature and it is also difficult to cool the temperature of carbon dioxide after inter-stage cooling to normal temperature, incomplete cooling is caused, resulting in a relatively high compression ratio required for the next-stage compression, so that a relatively high compression energy is still required for the next-stage compression, thus making the overall energy consumption of the system high and the efficiency low. Summary of the Invention

[0004] The purpose of the present invention is to provide a carbon dioxide capture and storage system and method coupling multi-stage compression and heat exchange, which can optimize energy during the transformation of carbon dioxide from atmospheric pressure to super-high pressure, reduce the compression ratio required for the next-stage compression, so that the compression energy required for the next-stage compression is reduced, thereby effectively reducing the energy consumption in the carbon dioxide storage process.

[0005] To achieve the above purpose, the technical solution provided by the present invention is as follows: A carbon dioxide capture and storage system coupling multi-stage compression and heat exchange includes a multi-stage compression component for multi-stage compression of carbon dioxide, and further includes: A first heat exchanger for introducing the flue gas generated by the gas turbine and using the heat in the flue gas to heat the multi-stage compressed carbon dioxide.

[0006] A high-temperature generator is connected to the first heat exchanger. An ammonia water concentrated solution is stored inside the high-temperature generator. The high-temperature generator uses the ammonia water concentrated solution to absorb the waste heat in the flue gas after heat exchange from the first heat exchanger to obtain normal-temperature flue gas, and the ammonia water concentrated solution after absorbing heat becomes ammonia water dilute solution and ammonia vapor.

[0007] A carbon capture device is connected to a high-temperature generator, uses the normal-temperature flue gas from the high-temperature generator to capture normal-temperature carbon dioxide, and allows the normal-temperature carbon dioxide to enter a multi-stage compression assembly.

[0008] A low-temperature generator is connected to the multi-stage compression assembly. There is a concentrated ammonia solution stored inside the low-temperature generator. The low-temperature generator is used to utilize the concentrated ammonia solution to absorb the heat generated when the multi-stage compression assembly performs multi-stage compression on normal-temperature carbon dioxide, so that the carbon dioxide after each compression returns to normal temperature, and the concentrated ammonia solution after heat absorption becomes a dilute ammonia solution and ammonia vapor.

[0009] A cooling circulation assembly is respectively connected to the high-temperature generator and the low-temperature generator, and is used to receive the dilute ammonia solution and ammonia vapor from the high-temperature generator and the low-temperature generator, mix the dilute ammonia solution and ammonia vapor and then turn them into a concentrated ammonia solution again and send them into the high-temperature generator and the low-temperature generator respectively for recycling.

[0010] The features of the present invention also lie in: Among them, the cooling circulation assembly includes: A solution heat exchanger stores a concentrated ammonia solution inside. The first outlet of the solution heat exchanger is respectively connected to the first inlet of the high-temperature generator and the first inlet of the low-temperature generator, and the first inlet of the solution heat exchanger is respectively connected to the first outlet of the high-temperature generator and the first outlet of the low-temperature generator.

[0011] An absorber, its first inlet is connected to the second outlet of the solution heat exchanger, its first outlet is connected to the second inlet of the solution heat exchanger, its third inlet and second outlet are respectively connected to the atmosphere, and its third inlet is connected to the second outlet of the low-temperature generator.

[0012] Among them, the first inlet of the absorber is connected to the second outlet of the solution heat exchanger through a first throttle valve, and the first outlet of the absorber is connected to the second inlet of the solution heat exchanger through a first booster pump.

[0013] Among them, a first condenser is arranged between the low-temperature generator and the absorber. The inlet of the first condenser is connected to the second outlet of the low-temperature generator. The outlet of the first condenser is connected to the first inlet of an evaporator through a second throttle valve. The first outlet of the evaporator is connected to the third inlet of the absorber. The second inlet of the evaporator is connected to the first inlet of a second condenser. The second outlet of the evaporator is connected to the first inlet of the second condenser.

[0014] Among them, the second outlet of the second condenser is connected to the inlet of the first booster pump. The outlet of the first booster pump is connected to the first inlet of a first heat exchanger. The first outlet of the first heat exchanger is connected to the inlet of a turbine expander. The outlet of the turbine expander is connected to the first inlet of a cooler. The first outlet of the cooler is connected to a carbon dioxide storage tank.

[0015] Among them, the multi-stage compression assembly includes: The first compressor, which is connected to the carbon capture device.

[0016] The second heat exchanger, which is respectively connected to the first compressor and the low-temperature generator.

[0017] The second compressor, which is connected to the second heat exchanger.

[0018] The third heat exchanger, which is respectively connected to the second compressor and the low-temperature generator.

[0019] The third compressor, which is connected to the third heat exchanger.

[0020] The fourth heat exchanger, which is respectively connected to the third compressor and the low-temperature generator.

[0021] A method for carbon dioxide capture and storage coupling multi-stage compression and heat exchange includes the following steps: Introduce the high-temperature and normal-pressure flue gas generated by the gas turbine into the first heat exchanger for heat exchange to obtain medium-temperature and normal-pressure flue gas, introduce the medium-temperature and normal-pressure flue gas into the high-temperature generator for heat exchange to obtain normal-temperature and normal-pressure flue gas, and introduce the normal-temperature flue gas into the carbon capture device to obtain normal-temperature and normal-pressure carbon dioxide.

[0022] Introduce the normal-temperature and normal-pressure carbon dioxide into the first compressor, the second compressor, and the third compressor in sequence, and use the second heat exchanger, the third heat exchanger, and the fourth heat exchanger in cooperation with the low-temperature generator for inter-stage cooling. The normal-temperature and normal-pressure carbon dioxide becomes medium-temperature and medium-pressure carbon dioxide, normal-temperature and medium-pressure carbon dioxide, medium-temperature and sub-high-pressure carbon dioxide, normal-temperature and sub-high-pressure carbon dioxide, medium-temperature and high-pressure carbon dioxide, and normal-temperature and high-pressure carbon dioxide in sequence.

[0023] Introduce the low-temperature and ultra-high-pressure carbon dioxide into the first heat exchanger for heating. The low-temperature and ultra-high-pressure carbon dioxide becomes high-temperature and ultra-high-pressure carbon dioxide. Introduce the high-temperature and ultra-high-pressure carbon dioxide into the turbine expander for expansion and output mechanical energy externally. The mechanical energy drives the generator to generate electricity to supply power to the system, offsetting part of the carbon dioxide compression power consumption. The high-temperature and ultra-high-pressure carbon dioxide becomes medium-temperature and high-pressure carbon dioxide.

[0024] Introduce the medium-temperature and high-pressure carbon dioxide into the cooler for cooling. The medium-temperature and high-pressure carbon dioxide becomes low-temperature and high-pressure carbon dioxide. Send the low-temperature and high-pressure carbon dioxide into the carbon dioxide storage tank for storage.

[0025] When the medium-temperature and normal-pressure flue gas enters the high-temperature generator for heat exchange to obtain normal-temperature and normal-pressure flue gas, the concentrated ammonia water solution in the high-temperature generator exchanges heat with the medium-temperature and normal-pressure flue gas, and the concentrated ammonia water solution becomes dilute ammonia water solution and ammonia vapor.

[0026] Among them, when using the second heat exchanger, the third heat exchanger, and the fourth heat exchanger in cooperation with the low-temperature generator for inter-stage cooling, the following steps are included: The concentrated ammonia water in the low-temperature generator sequentially enters the second heat exchanger, the third heat exchanger, and the fourth heat exchanger to respectively exchange heat with medium-temperature and medium-pressure carbon dioxide, medium-temperature and sub-high-pressure carbon dioxide, and medium-temperature and high-pressure carbon dioxide, obtaining ammonia vapor and dilute ammonia water.

[0027] The ammonia vapor from the low-temperature generator and the ammonia vapor from the high-temperature generator merge and then enter the first condenser for cooling, and the ammonia vapor becomes liquid ammonia.

[0028] The liquid ammonia is introduced into the evaporator, and the liquid ammonia exchanges heat with the normal-temperature and high-pressure carbon dioxide in the second condenser, and the liquid ammonia becomes ammonia vapor.

[0029] The ammonia vapor is introduced into the absorber. The dilute ammonia water generated in the high-temperature generator and the low-temperature generator enters the absorber through the solution heat exchanger. The dilute ammonia water absorbs the ammonia vapor to obtain concentrated ammonia water. The heat generated during the process of the dilute ammonia water absorbing the ammonia vapor is dissipated into the air. The concentrated ammonia water enters the solution heat exchanger, and the concentrated ammonia water in the solution heat exchanger respectively enters the high-temperature generator and the low-temperature generator for re-circulation.

[0030] Among them, the temperature of the normal-temperature and normal-pressure carbon dioxide is 15°C to 30°C, and the pressure is the standard atmospheric pressure; the temperature of the medium-temperature and medium-pressure carbon dioxide is 100°C to 200°C, and the pressure is 0.5 MPa to 2 MPa; the temperature of the normal-temperature and medium-pressure carbon dioxide is 15°C to 25°C, and the pressure is 0.5 MPa to 2 MPa; the temperature of the medium-temperature and sub-high-pressure carbon dioxide is 100°C to 200°C, and the pressure is 2 MPa to 5 MPa; the temperature of the normal-temperature and sub-high-pressure carbon dioxide is 15°C to 25°C, and the pressure is 2 MPa to 5 MPa; the temperature of the medium-temperature and high-pressure carbon dioxide is 100°C to 250°C, and the pressure is 5 MPa to 8 MPa; the temperature of the normal-temperature and high-pressure carbon dioxide is 15°C to 25°C, and the pressure is 5 MPa to 8 MPa; the temperature of the low-temperature and high-pressure carbon dioxide is -10°C to 10°C, and the pressure is 5 MPa to 8 MPa; the temperature of the low-temperature and super-pressure carbon dioxide is -10°C to 10°C, and the pressure is 10 MPa to 30 MPa; the temperature of the high-temperature and super-high-pressure carbon dioxide is 300°C to 500°C, and the pressure is 10 MPa to 30 MPa; the temperature of the medium-temperature and high-pressure carbon dioxide is 100°C to 200°C, and the pressure is 7.38 MPa to 15 MPa; the temperature of the low-temperature and high-pressure carbon dioxide is greater than 31.1°C, and the pressure is 7.38 MPa to 15 MPa; the temperature of the high-temperature and normal-pressure flue gas is 400°C to 600°C, and the pressure is the standard atmospheric pressure; the temperature of the medium-temperature and normal-pressure flue gas is 200°C to 400°C, and the pressure is the standard atmospheric pressure.

[0031] A multi-stage compression and heat exchange coupling carbon dioxide capture and storage system and method of the present invention has the following advantages: First, through the cooperation of the multi-stage compression component, the first heat exchanger, the high-temperature generator, the carbon capture device, the low-temperature generator and the cooling circulation component, the flue gas can be cooled from a high temperature to room temperature, enabling the carbon capture device to capture carbon dioxide at room temperature. Moreover, the carbon dioxide can return to room temperature after each compression, making the cooling of carbon dioxide more complete, reducing the compression energy required for each stage of carbon dioxide compression, thus effectively reducing the energy consumption in the carbon dioxide sequestration process and improving the compression efficiency.

[0032] Second, by adopting an ammonia water concentrated solution for the absorption refrigeration cycle and respectively utilizing the high-temperature waste heat of the gas turbine and the carbon dioxide compression heat according to the temperature grade, the cascade and full utilization of energy are realized, the energy efficiency of the system is improved, and at the same time, sufficient cold energy is ensured to be generated by the absorption refrigeration cycle to realize the complete condensation and liquefaction of carbon dioxide.

[0033] Third, by setting up a turbine expander, the heat in the high-temperature flue gas generated by the gas turbine can be fully utilized and converted into electric energy, which is equivalent to adding a supercritical carbon dioxide power generation process in the traditional pressurized sequestration process, offsetting part of the carbon dioxide compression power consumption.

[0034] Fourth, by synergistically using the high-temperature waste heat in the gas turbine flue gas and the multi-stage compression heat exchange technology, carbon dioxide in the flue gas can be efficiently captured and sequestered, and at the same time, the waste heat is used for heat exchange, reducing the overall energy consumption of the system and improving the carbon dioxide capture efficiency.

[0035] Fifth, the present invention adopts a multi-stage compression scheme to gradually compress the captured carbon dioxide from normal temperature and pressure to high pressure, and then condenses it through a condenser to ensure the safety and stability of carbon dioxide in the subsequent sequestration process, providing a reliable process guarantee for long-term sequestration.

[0036] Sixth, the system of the present invention has a compact structure and a high degree of process integration, can directly capture carbon dioxide on-site of the gas turbine, does not need to rely on external high-pressure storage tanks or complex electrochemical energy storage devices, is suitable for deployment at decentralized emission sources such as factories and power plants, realizes on-site capture and sequestration, and reduces the energy loss and safety risks during the carbon dioxide transportation process. Description of the Drawings

[0037] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0038] Figure 2 It is a schematic diagram of the overall process of the present invention.

[0039] Reference Signs: 1. Carbon capture device, 2. First control valve, 3. First compressor, 4. Second heat exchanger, 5. Second compressor, 6. Third heat exchanger, 7. Third compressor, 8. Fourth heat exchanger, 9. Second condenser, 10. Second booster pump, 11. First heat exchanger, 12. Turbine expander, 13. Cooler, 14. Carbon dioxide storage tank, 15. Solution heat exchanger, 16. High-temperature generator, 17. Low-temperature generator, 18. First condenser, 19. Second throttle valve, 20. Evaporator, 21. Absorber, 22. First booster pump, 23. First throttle valve, 24. Second control valve. Detailed implementation manner

[0040] The technical solutions in the present invention will be clearly and elaborately described below with reference to the accompanying drawings. Among them, in the description of the embodiments of the present invention, unless otherwise specified, " / " means "or". For example, A / B may mean A or B. The "and / or" in the text is only a description of the relationship between associated objects, indicating that there can be three relationships. For example, A and / or B may mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present invention, "a plurality of" means two or more than two. The following terms "first" and "second" are only used for descriptive purposes and cannot be understood as implying or indicating relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0041] As Figure 1As shown in the figure, the present invention provides a multi-stage compression heat exchange coupling carbon dioxide capture and storage system, including a multi-stage compression assembly, a first heat exchanger 11, a high-temperature generator 16, a carbon capture device 1, a low-temperature generator 17 and a cooling circulation assembly. The multi-stage compression assembly is used for multi-stage compression of carbon dioxide. The first heat exchanger 11 is connected to the multi-stage compression assembly. The first heat exchanger 11 is used to introduce the flue gas generated by the gas turbine and use the heat in the flue gas to heat the multi-stage compressed carbon dioxide, so as to facilitate the reduction of the temperature of the flue gas. The high-temperature generator 16 is respectively connected to the first heat exchanger 11. The high-temperature generator 16 stores concentrated ammonia water solution inside. The high-temperature generator 16 uses the concentrated ammonia water solution to absorb the waste heat in the flue gas to obtain normal-temperature flue gas. After absorbing heat, the concentrated ammonia water solution becomes dilute ammonia water and ammonia vapor. When the carbon capture device 1 captures carbon dioxide in the flue gas, normal-temperature carbon dioxide can be obtained. The carbon capture device 1 is connected to the high-temperature generator 16. The carbon capture device 1 uses the normal-temperature flue gas from the high-temperature generator 16 to capture normal-temperature carbon dioxide and makes the normal-temperature carbon dioxide enter the multi-stage compression assembly, so that the carbon dioxide entering the multi-stage compression assembly is normal-temperature carbon dioxide. The low-temperature generator 17 is connected to the multi-stage compression assembly. The low-temperature generator 17 stores concentrated ammonia water solution inside. The low-temperature generator 17 is used to use the concentrated ammonia water solution to absorb the heat generated during the multi-stage compression of normal-temperature carbon dioxide by the multi-stage compression assembly, so that the carbon dioxide after each compression returns to normal temperature. After absorbing heat, the concentrated ammonia water solution becomes dilute ammonia water and ammonia vapor. By enabling the carbon dioxide after each compression to return to normal temperature, the compression ratio required for the next-stage compression is reduced, the compression energy required for the next-stage compression is reduced, and the compression efficiency is improved. The cooling circulation assembly is respectively connected to the low-temperature generator 17 and the high-temperature generator 16. The cooling circulation assembly is used to receive the dilute ammonia water and ammonia vapor from the high-temperature generator 16 and the low-temperature generator 17, mix the dilute ammonia water and ammonia vapor and then turn them into concentrated ammonia water solution again and send them into the high-temperature generator 16 and the low-temperature generator 17 respectively for recycling. Through the cooperation of the carbon capture device 1, the multi-stage compression assembly, the first heat exchanger 11, the high-temperature generator 16, the low-temperature generator 17 and the cooling circulation assembly, the present invention can cool the flue gas from high temperature to normal temperature, enable the carbon capture device 1 to capture normal-temperature carbon dioxide, and enable the carbon dioxide after each compression to return to normal temperature, making the cooling of carbon dioxide more complete, reducing the compression energy required for each stage of carbon dioxide compression, thus effectively reducing the energy consumption during the carbon dioxide storage process and improving the compression efficiency.

[0042] As Figure 1As shown in the figure, the cooling cycle assembly includes a solution heat exchanger 15 and an absorber 21. The solution heat exchanger 15 stores concentrated ammonia water inside. Through the dual endothermic mechanism of physical dissolution and chemical ionization of the concentrated ammonia water, the endothermic effect is improved, facilitating the recovery of compressed carbon dioxide to room temperature. The first outlet of the solution heat exchanger 15 is respectively connected to the first inlet of the high-temperature generator 16 and the first inlet of the low-temperature generator 17. The first inlet of the solution heat exchanger 15 is respectively connected to the first outlet of the high-temperature generator 16 and the first outlet of the low-temperature generator 17. The first inlet of the absorber 21 is connected to the second outlet of the solution heat exchanger 15, and the first outlet of the absorber 21 is connected to the second inlet of the solution heat exchanger 15. The third inlet and the second outlet of the absorber 21 are respectively connected to the atmosphere, and the third inlet of the absorber 21 is connected to the second outlet of the low-temperature generator 17.

[0043] As Figure 1 shown, the first inlet of the absorber 21 and the second outlet of the solution heat exchanger 15 are connected through a first throttle valve 23. The first outlet of the absorber 21 and the second inlet of the solution heat exchanger 15 are connected through a first booster pump 22. The first throttle valve 23 is used to reduce the pressure of the dilute ammonia water entering the absorber 21. The first outlet of the absorber 21 and the second inlet of the solution heat exchanger 15 are connected through a first booster pump 22. The first booster pump 22 is used to pressurize the concentrated ammonia water entering the solution heat exchanger 15.

[0044] As Figure 1 shown, a first condenser 18 is provided between the low-temperature generator 17 and the absorber 21. The inlet of the first condenser 18 is connected to the second outlet of the low-temperature generator 17. The outlet of the first condenser 18 is connected to the first inlet of an evaporator 20 through a second throttle valve 19. The second throttle valve 19 is used to reduce the pressure of the liquid ammonia entering the evaporator 20. The first outlet of the evaporator 20 is connected to the third inlet of the absorber 21. The second inlet of the evaporator 20 is connected to the first inlet of a second condenser 9, and the second outlet of the evaporator 20 is connected to the first inlet of the second condenser 9.

[0045] As Figure 1 shown, the second outlet of the second condenser 9 is connected to the inlet of a second booster pump 10. The outlet of the second booster pump 10 is connected to the first inlet of a first heat exchanger 11. The first outlet of the first heat exchanger 11 is connected to the inlet of a turbine expander 12. The outlet of the turbine expander 12 is connected to the first inlet of a cooler 13. The first outlet of the cooler 13 is connected to a carbon dioxide storage tank 14.

[0046] As Figure 1As shown in the figure, the multi-stage compression assembly includes a first compressor 3, a second heat exchanger 4, a second compressor 5, a third heat exchanger 6, a third compressor 7 and a fourth heat exchanger 8. The inlet of the first compressor 3 is connected to the carbon capture device 1. The second heat exchanger 4 is respectively connected to the first compressor 3 and the low-temperature generator 17. The second compressor 5 is connected to the second heat exchanger 4. The third heat exchanger 6 is respectively connected to the second compressor 5 and the low-temperature generator 17. The third compressor 7 is connected to the third heat exchanger 6. The fourth heat exchanger 8 is respectively connected to the third compressor 7 and the low-temperature generator 17. That is, the first inlet of the second heat exchanger 4 is connected to the outlet of the first compressor 3. The first outlet of the second heat exchanger 4 is connected to the inlet of the second compressor 5. The outlet of the second compressor 5 is connected to the first inlet of the third heat exchanger 6. The first outlet of the third heat exchanger 6 is connected to the inlet of the third compressor 7. The outlet of the third compressor 7 is connected to the first inlet of the fourth heat exchanger 8. The first outlet of the fourth heat exchanger 8 is connected to the second inlet of the second condenser 9. The first outlet of the fourth heat exchanger 8, the second inlets of the second heat exchanger 4, the third heat exchanger 6 and the fourth heat exchanger 8 are respectively connected to the third outlet of the low-temperature generator 17. The second outlets of the second heat exchanger 4, the third heat exchanger 6 and the fourth heat exchanger 8 are respectively connected to the third inlet of the low-temperature generator 17.

[0047] As Figure 1 shown, a first control valve 2 is provided at the inlet of the first compressor 3. The second inlet of the first heat exchanger 11 is connected to the flue gas outlet of the gas turbine. A second control valve 24 is provided at the second inlet of the first heat exchanger 11. The second outlet of the first heat exchanger 11 is connected to the second inlet of the high-temperature generator 16. The second outlet of the high-temperature generator 16 is connected to the carbon capture device 1.

[0048] As Figure 2 shown, the present invention also provides a method for multi-stage compression heat exchange coupling carbon dioxide capture and storage, comprising the following steps: Introduce the high-temperature and normal-pressure flue gas generated by the gas turbine into the first heat exchanger 11 for heat exchange to obtain medium-temperature and normal-pressure flue gas. The medium-temperature and normal-pressure flue gas enters the high-temperature generator 16 for heat exchange to obtain normal-temperature and normal-pressure flue gas. The normal-temperature flue gas enters the carbon capture device 1 to obtain normal-temperature and normal-pressure carbon dioxide.

[0049] Introduce the normal-temperature and normal-pressure carbon dioxide into the first compressor 3, the second compressor 5 and the third compressor 7 in sequence, and use the second heat exchanger 4, the third heat exchanger 6, the fourth heat exchanger 8 and the low-temperature generator 17 to cooperate for inter-stage cooling. The normal-temperature and normal-pressure carbon dioxide becomes medium-temperature and medium-pressure carbon dioxide, normal-temperature and medium-pressure carbon dioxide, medium-temperature and sub-high-pressure carbon dioxide, normal-temperature and sub-high-pressure carbon dioxide, medium-temperature and high-pressure carbon dioxide and normal-temperature and high-pressure carbon dioxide in sequence.

[0050] Introduce normal-temperature and high-pressure carbon dioxide into the second condenser 9 for cooling. The normal-temperature and high-pressure carbon dioxide becomes low-temperature and high-pressure carbon dioxide. Then introduce the low-temperature and high-pressure carbon dioxide into the second booster pump 10 for pressurization, and the low-temperature and high-pressure carbon dioxide becomes low-temperature and ultra-high-pressure carbon dioxide.

[0051] Introduce the low-temperature and ultra-high-pressure carbon dioxide into the first heat exchanger 11 for heating. The low-temperature and ultra-high-pressure carbon dioxide becomes high-temperature and ultra-high-pressure carbon dioxide. Then introduce the high-temperature and ultra-high-pressure carbon dioxide into the turbine expander 12 for expansion to generate external mechanical energy. The mechanical energy drives the generator to generate electricity for the system, offsetting part of the carbon dioxide compression power consumption, and the high-temperature and ultra-high-pressure carbon dioxide becomes medium-temperature and high-pressure carbon dioxide.

[0052] Introduce the medium-temperature and high-pressure carbon dioxide into the cooler 13 for cooling. The medium-temperature and high-pressure carbon dioxide becomes low-temperature and high-pressure carbon dioxide, and then send the low-temperature and high-pressure carbon dioxide into the carbon dioxide storage tank 14 for sequestration.

[0053] Among them, when the medium-temperature and normal-pressure flue gas enters the high-temperature generator 16 for heat exchange to obtain the normal-temperature and normal-pressure flue gas, the concentrated ammonia water solution in the high-temperature generator 16 exchanges heat with the medium-temperature and normal-pressure flue gas, and the concentrated ammonia water solution becomes dilute ammonia water and ammonia vapor.

[0054] Among them, when using the second heat exchanger 4, the third heat exchanger 6, the fourth heat exchanger 8 and the low-temperature generator 17 for inter-stage cooling, it includes the following steps: The concentrated ammonia water solution in the low-temperature generator 17 successively enters the second heat exchanger 4, the third heat exchanger 6, and the fourth heat exchanger 8 to exchange heat with the medium-temperature and medium-pressure carbon dioxide, medium-temperature and sub-high-pressure carbon dioxide, and medium-temperature and high-pressure carbon dioxide respectively, obtaining ammonia vapor and dilute ammonia water.

[0055] After the ammonia vapor from the low-temperature generator 17 merges with the ammonia vapor from the high-temperature generator 16, it enters the first condenser 18 for cooling. The ammonia vapor becomes liquid ammonia.

[0056] Introduce the liquid ammonia into the evaporator 20. The liquid ammonia exchanges heat with the normal-temperature and high-pressure carbon dioxide in the second condenser 9, and the liquid ammonia becomes ammonia vapor.

[0057] Introduce the ammonia vapor into the absorber 21. The dilute ammonia water solutions generated in the high-temperature generator 16 and the low-temperature generator 17 enter the absorber 21 through the solution heat exchanger 15. The dilute ammonia water solution absorbs the ammonia vapor to obtain the concentrated ammonia water solution. The heat generated during the absorption of the ammonia vapor by the dilute ammonia water solution is dissipated into the air. The concentrated ammonia water solution enters the solution heat exchanger 15, and the concentrated ammonia water solution in the solution heat exchanger 15 enters the high-temperature generator 16 and the low-temperature generator 17 respectively for re-circulation.

[0058] Among them, the temperature of carbon dioxide at normal temperature and pressure is 15°C to 30°C, and the pressure is standard atmospheric pressure; the temperature of carbon dioxide at medium temperature and medium pressure is 100°C to 200°C, and the pressure is 0.5 MPa to 2 MPa; the temperature of carbon dioxide at normal temperature and medium pressure is 15°C to 25°C, and the pressure is 0.5 MPa to 2 MPa; the temperature of carbon dioxide at medium temperature and sub-high pressure is 100°C to 200°C, and the pressure is 2 MPa to 5 MPa; the temperature of carbon dioxide at normal temperature and sub-high pressure is 15°C to 25°C, and the pressure is 2 MPa to 5 MPa; the temperature of carbon dioxide at medium temperature and high pressure is 100°C to 250°C, and the pressure is 5 MPa to 8 MPa; the temperature of carbon dioxide at normal temperature and high pressure is 15°C to 25°C, and the pressure is 5 MPa to 8 MPa; the temperature of carbon dioxide at low temperature and high pressure is -10°C to 10°C, and the pressure is 5 MPa to 8 MPa; the temperature of carbon dioxide at low temperature and ultra-high pressure is -10°C to 10°C, and the pressure is 10 MPa to 30 MPa; the temperature of carbon dioxide at high temperature and ultra-high pressure is 300°C to 500°C, and the pressure is 10 MPa to 30 MPa; the temperature of carbon dioxide at medium temperature and high pressure is 100°C to 200°C, and the pressure is 7.38 MPa to 15 MPa; the temperature of carbon dioxide at low temperature and high pressure is greater than 31.1°C, and the pressure is 7.38 MPa to 15 MPa; the temperature of high-temperature flue gas at normal pressure is 400°C to 600°C, and the pressure is standard atmospheric pressure; the temperature of medium-temperature flue gas at normal pressure is 200°C to 400°C, and the pressure is standard atmospheric pressure.

[0059] Working principle: In the initial state, the first control valve 2 and the second control valve 24 are closed, and the device is in a shutdown state.

[0060] When the user needs to start the system for carbon capture and storage, the first control valve 2 and the second control valve 24 are opened. The high-temperature flue gas generated by the gas turbine enters the first heat exchanger 11, and after heat exchange of waste heat, it becomes medium-temperature flue gas at normal pressure. The medium-temperature flue gas at normal pressure enters the high-temperature generator 16, and after heat exchange and temperature reduction, it becomes flue gas at normal temperature and pressure. The flue gas at normal temperature and pressure enters the carbon capture device 1, and after sufficient contact with the absorbent, it is separated to obtain high-concentration carbon dioxide at normal temperature and pressure.

[0061] The carbon dioxide at normal temperature and pressure enters the first compressor 3, and after compression, it obtains carbon dioxide at medium temperature and medium pressure. Then, it exchanges heat with the concentrated ammonia solution in the first heat exchanger 4 and becomes carbon dioxide at normal temperature and medium pressure. The carbon dioxide at normal temperature and medium pressure enters the second compressor 5, and after compression, it obtains carbon dioxide at medium temperature and sub-high pressure. Then, it exchanges heat with the concentrated ammonia solution in the third heat exchanger 6 and becomes carbon dioxide at normal temperature and sub-high pressure. The carbon dioxide at normal temperature and sub-high pressure enters the third compressor 7, and after compression, it obtains carbon dioxide at medium temperature and high pressure. Then, it exchanges heat with the concentrated ammonia solution in the fourth heat exchanger 8 and becomes carbon dioxide at normal temperature and high pressure.

[0062] At normal temperature and high pressure, carbon dioxide enters the second condenser 9, where it is condensed to form low-temperature and high-pressure carbon dioxide, i.e., liquid carbon dioxide. The low-temperature and high-pressure carbon dioxide is pressurized by the second booster pump 10 to reduce the compression energy of the second booster pump 10 for compressing carbon dioxide, and it becomes low-temperature and ultra-high-pressure carbon dioxide. The low-temperature and ultra-high-pressure carbon dioxide enters the first heat exchanger 11 to exchange heat with high-temperature and normal-pressure flue gas. After heat exchange, it becomes high-temperature and ultra-high-pressure carbon dioxide. The high-temperature and ultra-high-pressure carbon dioxide enters the turbine expander 12, where it expands to become medium-temperature and high-pressure carbon dioxide, and at the same time, it outputs work externally, converting mechanical energy into electrical energy. The generated electrical energy is transmitted to the first compressor 3, the second compressor 5, the third compressor 7, and the second booster pump 10 to offset part of the power consumption for compressing carbon dioxide. The medium-temperature and high-pressure carbon dioxide enters the cooler 13 to be cooled and its temperature drops. The medium-temperature and high-pressure carbon dioxide becomes low-temperature and high-pressure carbon dioxide, and finally, the low-temperature and high-pressure carbon dioxide is sent to the carbon dioxide storage tank 14 for storage.

[0063] In the solution heat exchanger 15, the concentrated ammonia water enters the high-temperature generator 16 and the low-temperature generator 17 respectively. The concentrated ammonia water is heated by the medium-temperature flue gas in the high-temperature generator 16 to obtain ammonia vapor and dilute ammonia water. The medium-temperature and normal-pressure flue gas becomes normal-temperature and normal-pressure flue gas. The ammonia vapor enters the low-temperature generator 17, and the concentrated ammonia water in the solution heat exchanger 15 enters the low-temperature generator 17. The concentrated ammonia water sequentially enters the second heat exchanger 4, the third heat exchanger 6, and the fourth heat exchanger 8 to exchange heat with medium-temperature and medium-pressure carbon dioxide, medium-temperature and sub-high-pressure carbon dioxide, and medium-temperature and high-pressure carbon dioxide respectively, to obtain ammonia vapor and dilute ammonia water. After the ammonia vapor in the low-temperature generator 17 and the ammonia vapor in the high-temperature generator 16 merge, they enter the second condenser 18 for cooling, and the ammonia vapor becomes liquid ammonia.

[0064] The liquid ammonia passes through the second throttle valve 19 to reduce the pressure and enters the evaporator 20, where it exchanges heat with the normal-temperature and high-pressure carbon dioxide in the second condenser 9. The liquid ammonia becomes ammonia vapor. The ammonia vapor passes through the first throttle valve 23 to reduce the pressure and then enters the absorber 21. The dilute ammonia water generated in the high-temperature generator 16 and the low-temperature generator 17 enters the absorber 21 through the solution heat exchanger 15. The dilute ammonia water absorbs the ammonia vapor to obtain concentrated ammonia water. The heat generated during the process of the dilute ammonia water absorbing the ammonia vapor is dissipated into the air. The concentrated ammonia water is pressurized by the first booster pump 22 and then enters the solution heat exchanger 15 for re-circulation.

[0065] It will be understood that the present invention is described by way of some embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. Additionally, under the teaching of the present invention, these features and embodiments can be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present invention are within the scope protected by the present invention.

Claims

1. A carbon dioxide capture and storage system coupling multi-stage compression and heat exchange, comprising a multi-stage compression assembly for multi-stage compression of carbon dioxide, characterized in that, It further includes: A first heat exchanger (11) for introducing the flue gas generated by a gas turbine and using the heat in the flue gas to heat the multi-stage compressed carbon dioxide; A high-temperature generator (16) connected to the first heat exchanger (11). An ammonia water concentrated solution is stored inside the high-temperature generator (16). The high-temperature generator (16) uses the ammonia water concentrated solution to absorb the waste heat in the flue gas after heat exchange from the first heat exchanger (11) to obtain normal-temperature flue gas. The ammonia water concentrated solution after absorbing heat becomes ammonia water dilute solution and ammonia vapor; A carbon capture device (1) connected to the high-temperature generator (16) for capturing normal-temperature carbon dioxide using the normal-temperature flue gas from the high-temperature generator (16) and enabling the normal-temperature carbon dioxide to enter the multi-stage compression assembly; A low-temperature generator (17) connected to the multi-stage compression assembly. An ammonia water concentrated solution is stored inside the low-temperature generator (17). The low-temperature generator (17) is used to absorb the heat generated when the multi-stage compression assembly performs multi-stage compression on normal-temperature carbon dioxide, so that the carbon dioxide after each compression returns to normal temperature. The ammonia water concentrated solution after absorbing heat becomes ammonia water dilute solution and ammonia vapor; A cooling circulation assembly, respectively connected to the high-temperature generator (16) and the low-temperature generator (17), for receiving the ammonia water dilute solution and ammonia vapor from the high-temperature generator (16) and the low-temperature generator (17), mixing the ammonia water dilute solution and ammonia vapor and then turning them into ammonia water concentrated solution again and respectively sending them into the high-temperature generator (16) and the low-temperature generator (17) for recycling.

2. The carbon dioxide capture and storage system with multi-stage compression and heat exchange coupling according to claim 1, wherein The cooling circulation assembly includes: A solution heat exchanger (15) storing an ammonia water concentrated solution. The first outlet of the solution heat exchanger (15) is respectively connected to the first inlet of the high-temperature generator (16) and the first inlet of the low-temperature generator (17). The first inlet of the solution heat exchanger (15) is respectively connected to the first outlet of the high-temperature generator (16) and the first outlet of the low-temperature generator (17); An absorber (21) with its first inlet connected to the second outlet of the solution heat exchanger (15). The first outlet of the absorber (21) is connected to the second inlet of the solution heat exchanger (15). The third inlet and the second outlet of the absorber (21) are respectively connected to the atmosphere. The third inlet of the absorber (21) is connected to the second outlet of the low-temperature generator (17).

3. The carbon dioxide capture and storage system with multi-stage compression and heat exchange coupling according to claim 2, characterized in that, The first inlet of the absorber (21) is connected to the second outlet of the solution heat exchanger (15) through a first throttle valve (23). The first outlet of the absorber (21) is connected to the second inlet of the solution heat exchanger (15) through a first booster pump (22).

4. A carbon dioxide capture and storage system with multi-stage compression and heat exchange coupling according to claim 2, characterized in that, A first condenser (18) is provided between the low-temperature generator (17) and the absorber (21). The inlet of the first condenser (18) is connected to the second outlet of the low-temperature generator (17). The outlet of the first condenser (18) is connected to the first inlet of the evaporator (20) through a second throttle valve (19). The first outlet of the evaporator (20) is connected to the third inlet of the absorber (21). The second inlet of the evaporator (20) is connected to the first inlet of the second condenser (9). The second outlet of the evaporator (20) is connected to the first inlet of the second condenser (9).

5. A carbon dioxide capture and storage system with multi-stage compression and heat exchange coupling according to claim 4, characterized in that The second outlet of the second condenser (9) is connected to the inlet of a second booster pump (10). The outlet of the second booster pump (10) is connected to the first inlet of the first heat exchanger (11). The first outlet of the first heat exchanger (11) is connected to the inlet of a turboexpander (12). The outlet of the turboexpander (12) is connected to the first inlet of a cooler (13). The first outlet of the cooler (13) is connected to a carbon dioxide storage tank (14).

6. A carbon dioxide capture and storage system with multi-stage compression and heat exchange coupling according to claim 5, characterized in that, The multi-stage compression assembly includes: A first compressor (3), connected to the carbon capture device (1); A second heat exchanger (4), connected to the first compressor (3) and the low-temperature generator (17) respectively; A second compressor (5), connected to the second heat exchanger (4); A third heat exchanger (6), connected to the second compressor (5) and the low-temperature generator (17) respectively; A third compressor (7), connected to the third heat exchanger (6); A fourth heat exchanger (8), connected to the third compressor (7) and the low-temperature generator (17) respectively.

7. A method for carbon dioxide capture and storage with multi-stage compression and heat exchange coupling, characterized in that, Using the system as claimed in claim 6, comprising the following steps: Introduce the high-temperature normal-pressure flue gas generated by the gas turbine into the first heat exchanger (11) for heat exchange to obtain medium-temperature normal-pressure flue gas. The medium-temperature normal-pressure flue gas enters the high-temperature generator (16) for heat exchange to obtain normal-temperature normal-pressure flue gas. The normal-temperature flue gas enters the carbon capture device (1) to obtain normal-temperature normal-pressure carbon dioxide; Introduce the normal-temperature normal-pressure carbon dioxide into the first compressor (3), the second compressor (5), and the third compressor (7) in sequence, and use the second heat exchanger (4), the third heat exchanger (6), and the fourth heat exchanger (8) in cooperation with the low-temperature generator (17) for inter-stage cooling. The normal-temperature normal-pressure carbon dioxide becomes medium-temperature medium-pressure carbon dioxide, normal-temperature medium-pressure carbon dioxide, medium-temperature sub-high-pressure carbon dioxide, normal-temperature sub-high-pressure carbon dioxide, medium-temperature high-pressure carbon dioxide, and normal-temperature high-pressure carbon dioxide in sequence; Introduce the normal-temperature high-pressure carbon dioxide into the second condenser (9) for cooling and temperature reduction. The normal-temperature high-pressure carbon dioxide becomes low-temperature high-pressure carbon dioxide. Introduce the low-temperature high-pressure carbon dioxide into the second booster pump (10) for pressurization. The low-temperature high-pressure carbon dioxide becomes low-temperature ultra-high-pressure carbon dioxide; Introduce low-temperature and super-high-pressure carbon dioxide into the first heat exchanger (11) for heating. The low-temperature and super-high-pressure carbon dioxide becomes high-temperature and super-high-pressure carbon dioxide. Then introduce the high-temperature and super-high-pressure carbon dioxide into the turbine expander (12) for expansion and output mechanical energy externally. The mechanical energy drives the generator to generate electricity to supply power to the system, offsetting part of the carbon dioxide compression power consumption. The high-temperature and super-high-pressure carbon dioxide becomes medium-temperature and high-pressure carbon dioxide; Introduce the medium-temperature and high-pressure carbon dioxide into the cooler (13) for cooling. The medium-temperature and high-pressure carbon dioxide becomes low-temperature and high-pressure carbon dioxide. Then send the low-temperature and high-pressure carbon dioxide into the carbon dioxide storage tank (14) for storage.

8. A method for carbon dioxide capture and storage with multi-stage compression and heat exchange coupling according to claim 7, characterized in that When the medium-temperature and normal-pressure flue gas enters the high-temperature generator (16) for heat exchange to obtain normal-temperature and normal-pressure flue gas, the concentrated ammonia water solution in the high-temperature generator (16) exchanges heat with the medium-temperature and normal-pressure flue gas. The concentrated ammonia water solution becomes dilute ammonia water solution and ammonia vapor.

9. A method for carbon dioxide capture and storage coupling multi-stage compression and heat exchange according to claim 8, characterized in that, When using the second heat exchanger (4), the third heat exchanger (6), the fourth heat exchanger (8) and the low-temperature generator (17) to cooperate for inter-stage cooling, it includes the following steps: The concentrated ammonia water solution in the low-temperature generator (17) successively enters the second heat exchanger (4), the third heat exchanger (6), and the fourth heat exchanger (8) to exchange heat with medium-temperature and medium-pressure carbon dioxide, medium-temperature and sub-high-pressure carbon dioxide, and medium-temperature and high-pressure carbon dioxide respectively, obtaining ammonia vapor and dilute ammonia water solution; The ammonia vapor from the low-temperature generator (17) and the ammonia vapor from the high-temperature generator (16) merge and then enter the first condenser (18) for cooling. The ammonia vapor becomes liquid ammonia; Introduce the liquid ammonia into the evaporator (20). The liquid ammonia exchanges heat with the normal-temperature and high-pressure carbon dioxide in the second condenser (9). The liquid ammonia becomes ammonia vapor; Introduce the ammonia vapor into the absorber (21). The dilute ammonia water solution generated in the high-temperature generator (16) and the low-temperature generator (17) enters the absorber (21) through the solution heat exchanger (15). The dilute ammonia water solution absorbs the ammonia vapor to obtain concentrated ammonia water solution. The heat generated during the absorption of ammonia vapor by the dilute ammonia water solution is dissipated into the air. The concentrated ammonia water solution enters the solution heat exchanger (15). In the solution heat exchanger (15), the concentrated ammonia water solution enters the high-temperature generator (16) and the low-temperature generator (17) respectively for re-circulation.

10. A method for carbon dioxide capture and storage by coupling multi-stage compression and heat exchange according to claim 9, characterized in that, The temperature of the normal-temperature and normal-pressure carbon dioxide is 15°C to 30°C, and the pressure is the standard atmospheric pressure; the temperature of the medium-temperature and medium-pressure carbon dioxide is 100°C to 200°C, and the pressure is 0.5 MPa to 2 MPa; the temperature of the normal-temperature and medium-pressure carbon dioxide is 15°C to 25°C, and the pressure is 0.5 MPa to 2 MPa; the temperature of the medium-temperature and sub-high-pressure carbon dioxide is 100°C to 200°C, and the pressure is 2 MPa to 5 MPa; the temperature of the normal-temperature and sub-high-pressure carbon dioxide is 15°C to 25°C, and the pressure is 2 MPa to 5 MPa; the temperature of the medium-temperature and high-pressure carbon dioxide is 100°C to 250°C, and the pressure is 5 MPa to 8 MPa; the temperature of the normal-temperature and high-pressure carbon dioxide is 15°C to 25°C, and the pressure is 5 MPa to 8 MPa; the temperature of the low-temperature and high-pressure carbon dioxide is -10°C to 10°C, and the pressure is 5 MPa to 8 MPa; the temperature of the low-temperature and ultra-high-pressure carbon dioxide is -10°C to 10°C, and the pressure is 10 MPa to 30 MPa; the temperature of the high-temperature and ultra-high-pressure carbon dioxide is 300°C to 500°C, and the pressure is 10 MPa to 30 MPa; the temperature of the medium-temperature and high-pressure carbon dioxide is 100°C to 200°C, and the pressure is 7.38 MPa to 15 MPa; the temperature of the low-temperature and high-pressure carbon dioxide is greater than 31.1°C, and the pressure is 7.38 MPa to 15 MPa; the temperature of the high-temperature and normal-pressure flue gas is 400°C to 600°C, and the pressure is the standard atmospheric pressure; the temperature of the medium-temperature and normal-pressure flue gas is 200°C to 400°C, and the pressure is the standard atmospheric pressure.

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