A cogeneration self-balancing carbon capture system

Abstract

The present application belongs to the technical field of flue gas carbon capture and waste heat utilization, and particularly relates to a combined heat and power self-balancing carbon capture system. The system comprises a flue gas carbon capture system, a high-temperature steam heat pump system and a regenerated gas treatment system. The shell side of a steam reboiler is connected to the bottom of a lean liquid of a regenerator to form a shell side circulation. The first tube side of the steam reboiler is connected to a heat pump compressor and an expansion valve to participate in the circulation of the high-temperature steam heat pump system. An ejector and a gas-liquid separator are connected to the second tube side of the steam reboiler. A regenerated gas expander is connected to the heat pump compressor and drives the heat pump compressor to work. In the flue gas carbon capture system, the lean liquid flows out of the lean-lean liquid heat exchanger, enters the hot side of an evaporator, and then enters a spray section at the upper part of an absorption tower. The carbon capture system directly heats the high-temperature lean liquid to generate lean liquid steam, thereby improving the heat exchange efficiency. The flash system is cancelled, and the volume, cost and energy consumption of the entire heat pump system are greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of flue gas carbon capture and waste heat utilization technology, specifically relating to a combined heat and power self-balancing carbon capture system. Background Technology

[0002] Carbon capture, utilization and storage (CCUS) is a key technology for achieving carbon dioxide emission reduction and resource utilization.

[0003] For post-combustion carbon capture technology, chemical absorption (amine-based carbon capture) offers significant advantages in terms of initial investment and land area when applied to low-concentration carbon-containing flue gas. Its working principle is as follows: After dust removal and desulfurization, the flue gas, after preliminary cooling and pretreatment, enters from the bottom of the absorption tower, where it comes into counter-current contact with the absorbent solution sprayed from the top. CO2 in the flue gas reacts chemically with the absorbent, and the CO2-free flue gas is discharged from the top of the absorption tower. The CO2-rich solution is pumped out of the absorption tower, exchanges heat with the lean solution in a lean-rich solution heat exchanger, and is then sent to a regeneration tower for desorption and regeneration. The CO2 bound in the rich solution is released by heating. The lean solution at the bottom of the regeneration tower, under the action of a lean solution pump, undergoes heat exchange in a lean-rich solution heat exchanger and is cooled to the required temperature in a lean solution cooler before being sprayed from the top of the absorption tower for the next absorption cycle.

[0004] Currently, the biggest technical problem with chemical absorption is the high regeneration energy consumption (requiring a relatively high regeneration temperature of 120℃~140℃, with regeneration energy consumption of 2~3 GJ / t CO2) and high operating costs (the capture cost of CCUS projects in the domestic power industry is 300~600 yuan / t CO2). Optimizing the system to achieve low energy consumption has enormous potential for energy saving.

[0005] Most existing carbon capture systems use external low-pressure steam (120℃~140℃) as the heat source for the reboiler of the regeneration tower. In the steam reboiler at the bottom of the regeneration tower, the lean liquor at the bottom exchanges heat with the steam, becoming lean liquor steam, which then enters the lower part of the regeneration tower. This lean liquor steam then exchanges heat with the rich liquor sprayed from top to bottom in the regeneration tower, releasing latent heat to release CO2 and complete the amine regeneration. Currently, capturing 1 ton of CO2 typically requires 1.1~2.0 tons of low-pressure steam, which is the maximum energy consumption in a carbon capture system. Power plants usually use low-pressure steam extraction from steam turbines, but as the scale of carbon capture expands, the amount of steam extracted increases significantly, inevitably affecting the unit's output. On the other hand, the high-temperature lean liquor at the bottom of the regeneration tower must first be pre-cooled by a lean-rich liquor heat exchanger (e.g., cooled to 80°C by the rich liquor), and then further cooled to a lower temperature (e.g., 40°C by industrial circulating water) by a lean liquor cooler before entering the absorption tower. Most of the energy used for regenerating the externally supplied amine liquor is wasted by the external circulating water in the lean liquor cooler, which is one of the main reasons for the high energy consumption of the carbon capture system.

[0006] Industrial high-temperature heat pumps can significantly save energy consumption by recovering and upgrading waste heat from process technologies. CN221846619U discloses a heat recovery system that couples carbon dioxide capture with flue gas waste heat, proposing the use of a high-temperature steam heat pump to indirectly recover waste heat from the flue gas spray cooling of a scrubbing tower to produce steam for use in a reboiler. However, due to the low temperature of the flue gas after the desulfurization tower, the heat pump system extracts very little heat from the flue gas, insufficient to produce a large amount of steam for self-sufficiency. Furthermore, the scrubbing cooling water directly contacts the relatively dirty flue gas after desulfurization for heat and mass exchange. The cooling water contains solid particles and is acidic, making the evaporator of the heat pump unit prone to scaling. CN118328587A discloses a self-heating carbon dioxide capture system that utilizes three waste heat recovery heat pumps to extract heat from different locations within the carbon capture system for heating. However, the control process is highly complex, the system has low reliability, and lacks operability. Furthermore, its steam heat pump system employs a method of first generating high-temperature hot water followed by flash evaporation, resulting in a low steam production ratio, a large water circulation system volume, and high energy consumption. Finally, in this scheme, the high-temperature rich liquid heated by the condenser will release some CO2 before entering the top of the regeneration tower, posing challenges to condenser design and impacting the operation of the regeneration tower, leading to a deterioration in overall desorption efficiency and a reduced capture rate. In summary, existing research on waste heat recovery in carbon capture based on high-temperature heat pumps still faces numerous technical challenges.

[0007] It is essential to further improve existing carbon capture waste heat recovery systems, increase the self-heating regeneration supply rate, improve system performance, and reduce system size and energy consumption. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a combined heat and power self-balancing carbon capture system.

[0009] The present invention adopts the following technical solution: A combined heat and power self-balancing carbon capture system includes a flue gas carbon capture system, a high-temperature steam heat pump system, and a regenerated gas treatment system coupled through a steam reboiler. The high-temperature steam heat pump system includes an evaporator, a heat pump compressor, a first tube side of the steam reboiler, and an expansion valve connected in sequence. The first tube side of the steam reboiler acts as a condenser in the circulation of the high-temperature steam heat pump system. The regenerated gas treatment system includes an ejector, a second tube side of the steam reboiler, a gas-liquid separator, and a regenerated gas expander connected in sequence from the regenerated gas outlet at the top of the regeneration tower. The shell side of the steam reboiler is connected to the lean liquid at the bottom of the regeneration tower to form a shell-side circulation. The regenerated gas expander is also connected to the heat pump compressor and drives the heat pump compressor to perform work. In the flue gas carbon capture system, the lean liquid at the bottom of the regeneration tower flows out of the lean-rich liquid heat exchanger, first enters the hot side of the evaporator, and then enters the spray section at the top of the absorption tower from the lean liquid cooler.

[0010] Preferably, in the flue gas carbon capture system, the low-temperature rich liquid outlet at the bottom of the absorption tower is connected to the reflux section at the top of the regeneration tower in sequence through a rich liquid pump and a lean-rich liquid heat exchanger, and the high-temperature lean liquid outlet at the bottom of the regeneration tower is connected to the spray section at the top of the absorption tower in sequence through the lean-rich liquid heat exchanger, the lean liquid pump, the hot side of the evaporator, and the lean liquid cooler.

[0011] Preferably, the regeneration gas outlet at the top of the regeneration tower is connected to the auxiliary inlet of the ejector, and the main inlet of the ejector is connected to an external water and steam supply pipeline.

[0012] Preferably, the ejector and the gas-liquid separator are respectively connected to the second tube inlet and the second tube outlet of the steam reboiler, and a condensate recovery pipeline is also provided between the second tube outlet of the steam reboiler and the gas-liquid separator.

[0013] Preferably, the refrigerant of the high-temperature steam heat pump system is R1233zd(E) or R1336mzz(Z).

[0014] Preferably, in the high-temperature steam heat pump system, the condensation temperature of the refrigerant in the first tube of the steam reboiler is ≥120°C to ensure that the lean liquid can be heated to 120°C to complete the regeneration process; the evaporation temperature is ≤ the lean liquid outlet temperature of the evaporator to ensure that the lean liquid can be cooled.

[0015] Preferably, the lean liquor is cooled to ≤40°C in a lean liquor cooler before entering the spray section at the top of the absorption tower.

[0016] The beneficial effects of this invention are as follows: 1) The high-temperature steam heat pump system, regenerated gas treatment system, and flue gas carbon capture system are deeply coupled to achieve a self-balancing power and heat supply. The evaporator of the high-temperature steam heat pump system is located between the lean liquid pump and the lean liquid cooler, extracting heat from the area of ​​greatest heat waste in the existing system. It can directly utilize the existing steam reboiler to achieve refrigerant condensation inside the pipes and evaporation of lean liquid outside the pipes, requiring only a modification to the existing reboiler without the need for a separate condenser. This high-temperature steam heat pump system can achieve large-capacity, high-grade heating (MW level and above), with a self-heating regeneration supply rate of up to 70%, significantly reducing external regeneration energy consumption (after commissioning, the external steam supply can be reduced to 30% of the original amount). In addition, under certain lean liquid temperature drop conditions, high system performance (COP above 3.0) can be achieved. The regenerated gas treatment system introduces a power-free ejector to replace the original high-power regenerated gas compressor. It uses externally supplied high-pressure (0.2~0.36 MPa) steam to eject the low-pressure regenerated gas from the top of the regeneration tower, thus completing the regenerated gas pressurization process. Simultaneously, as the medium-pressure mixed gas at the ejector outlet is cooled by lean liquid in the steam reboiler, a large amount of latent heat of water vapor (including not only externally supplied water vapor but also water vapor in the regenerated gas) is recovered, thus recovering both work and heat. Finally, the regenerated gas treatment system introduces a regenerated gas expander, replacing the original external cooling process with self-expansion cooling. This not only cools the regenerated gas to facilitate subsequent CO2 liquefaction processes but also allows the output shaft work to be used to drive the heat pump compressor, thereby achieving work recovery.

[0017] 2. Unlike traditional methods that heat condensate to generate steam, which then heats the high-temperature lean liquid to produce lean liquid steam, the high-temperature steam heat pump system proposed in this application directly heats the high-temperature lean liquid at the bottom of the regeneration tower to generate lean liquid steam, reducing intermediate heat exchange stages and improving heat exchange efficiency. Furthermore, traditional high-temperature steam heat pump systems first produce a high-temperature liquid and then flash-evaporate it into steam; the improved system in this application eliminates the flash-evaporation system, significantly reducing the overall size, cost, and energy consumption of the heat pump system. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a typical existing chemical absorption carbon capture process.

[0019] Figure 2 This is a schematic diagram of a carbon capture system based on a combined heat and power supply self-balancing scheme according to the present application.

[0020] Figure 3 The diagram shows the inlet and outlet of the shell side, first tube side, and second tube side of the steam reboiler in this application.

[0021] The meanings of the symbols marked in the figure are as follows: 10 - Steam reboiler, 111 - Shell side inlet, 112 - Shell side outlet, 121 - First tube side inlet, 122 - First tube side outlet, 131 - Second tube side inlet, 132 - Second tube side outlet; 21-Heat pump compressor, 22-Evaporator, 23-Expansion valve; 31-Scrubber, 311-Exhaust fan, 32-Absorber, 321-Rich liquid outlet, 33-Regeneration tower, 331-Regeneration gas outlet, 332-Lean liquid outlet, 333-Circulation outlet, 334-Circulation inlet, 335-Regeneration gas compressor, 336-Regeneration gas cooler; 41-Ejector, 411-Auxiliary inlet, 412-Main inlet, 42-Gas-liquid separator, 43-Regenerated gas expander, 44-Condensate recovery pipeline; 50 - Lean / Rich solution heat exchanger, 51 - Lean solution cooler, 52 - Rich solution pump, 53 - Lean solution pump; 60 - External water and steam supply pipeline. Detailed Implementation

[0022] The technical solution of the present invention will be described in more detail below with reference to the embodiments and accompanying drawings.

[0023] like Figure 1 The image shows a typical existing chemical absorption carbon capture system, including a flue gas carbon capture system and a regenerated gas treatment system. For a 50,000-ton / year carbon capture project, the emissions after the desulfurization tower are 32,900 Nm³. 3 The flue gas, at a temperature of 60℃, first enters the lower part of scrubbing tower 31, where it is cooled to 40℃ by water washing and then discharged from the top of scrubbing tower 31. Subsequently, under the action of the induced draft fan, it enters the lower part of absorption tower 32, where it is sprayed downwards by a 175m³ of gas. 3After the lean liquor has fully reacted and removed CO2, it is discharged from the top of the absorption tower 32. The lean liquor, having absorbed CO2, becomes rich liquor. The rich liquor at 65°C flows out from the bottom of the absorption tower 32, is pressurized by the rich liquor pump 52, and enters the lean-rich liquor heat exchanger 50, where it is preheated to 98°C by the lean liquor. It then enters the upper part of the regeneration tower 33. In the steam reboiler 10, externally supplied low-pressure steam at 6.9°C, 0.35MPa, and 140°C flows through the tubes, heating the 108°C lean liquor flowing through the shell side of the steam reboiler 10 from the bottom of the regeneration tower 33. This generates 120°C lean liquor steam, which is then sent to the lower part of the regeneration tower 33. The low-pressure steam after heat exchange is condensed and recovered. The rich liquor in the regeneration tower 33, heated by the high-temperature lean liquor steam, desorbs CO2 and is discharged from the top of the regeneration tower 33. The lean liquor steam condenses back into lean liquor and returns to the bottom of the regeneration tower 33. The lean liquor drawn from the bottom of regeneration tower 33 undergoes heat exchange in lean-rich liquor heat exchanger 50, reducing its temperature from 108℃ to 80℃. Then, it is pressurized to 0.6MPa by lean liquor pump 53 and enters lean liquor cooler 51, where it is further cooled to 40℃ by external industrial circulating water before entering the upper part of absorption tower 32 and being sprayed into the tower. It can be seen that during this process, 175m... 3 The lean solution is cooled from 80°C to 40°C in the lean solution cooler, resulting in a waste of approximately 8.2 MW of heat.

[0024] For the regeneration gas treatment system, 6.25t / h (3180Nm³) 3 CO2 (1.4 t / h) along with a large amount of water vapor (1.4 t / h) is discharged from the top of regeneration tower 33 at a temperature of approximately 108℃ and a pressure of approximately 0.18 MPa. It then enters regeneration gas compressor 335, where it is compressed to 0.20~0.22 MPa. Afterward, it enters regeneration gas cooler 336 (cooled by external circulating water) for cooling, where a large amount of water vapor is condensed and cooled to 40℃. The gas then proceeds to gas-liquid separator 42. In gas-liquid separator 42, the entrained condensate is separated, and the CO2 gas is then sent to liquefaction and other post-treatment systems. It can be seen that, on the one hand, regeneration gas compressor 335 consumes a huge amount of power; on the other hand, the sensible heat of the regeneration gas and a large amount of latent heat of water vapor (approximately 1 MW) are wasted by the external circulating water, ultimately resulting in high energy consumption of the carbon capture system.

[0025] Example 1 like Figure 2 , Figure 3 As shown, a combined heat and power self-balancing carbon capture system includes a flue gas carbon capture system, a high-temperature steam heat pump system, and a regenerated gas treatment system. The flue gas carbon capture system, the high-temperature steam heat pump system, and the regenerated gas treatment system are coupled through a steam reboiler 10.

[0026] Specifically, the flue gas carbon capture system includes a scrubbing tower 31, an absorption tower 32, and a regeneration tower 33 connected in sequence; the high-temperature steam heat pump system includes an evaporator 22, a heat pump compressor 21, a first tube of a steam reboiler 10, and an expansion valve 23 connected in sequence; and the regeneration gas treatment system includes an ejector 41, a second tube of a steam reboiler 10, a gas-liquid separator 42, and a regeneration gas expander 43 connected in sequence from the regeneration gas outlet 331 at the top of the regeneration tower 33.

[0027] In the flue gas carbon capture system, the low-temperature rich liquid outlet 321 at the bottom of the absorption tower 32 is connected to the reflux section at the top of the regeneration tower 33 in sequence through the rich liquid pump 52 and the lean-rich liquid heat exchanger 50. The high-temperature lean liquid outlet 332 at the bottom of the regeneration tower 33 is connected to the spray section at the top of the absorption tower 32 in sequence through the lean-rich liquid heat exchanger 50, the lean liquid pump 53, the hot side of the evaporator 22, and the lean liquid cooler 51.

[0028] The high-temperature lean liquid at the bottom of the regeneration tower 33 is connected to the shell-side inlet 111 and shell-side outlet 112 of the steam reboiler 10 via the circulation outlet 333 and circulation inlet 334, respectively, forming the shell-side circulation of the steam reboiler 10. The steam reboiler 10 has two tube sides, where the first tube side is connected to the heat pump compressor 21 and the expansion valve 23 and participates in the circulation of the high-temperature steam heat pump system as a condenser, and the second tube side is connected to the ejector 41 and the gas-liquid separator 42, forming part of the pipeline of the regeneration gas treatment system. Specifically, the outlet of the heat pump compressor 21 is connected to the first tube-side inlet 121 of the steam reboiler 10, and the first tube-side outlet 122 is connected to the inlet of the expansion valve 23; the outlet of the ejector 41 is connected to the second tube-side inlet 131 of the steam reboiler 10, and the second tube-side outlet 132 is connected to the inlet of the gas-liquid separator 42.

[0029] In the regenerated gas treatment system, the regenerated gas outlet 331 at the top of the regenerated tower 33 is connected to the auxiliary inlet 411 of the ejector 41, the main inlet 412 of the ejector 41 is connected to the external water and steam supply pipeline 60, a condensate recovery pipeline 44 is provided between the second tube outlet 132 of the steam reboiler 10 and the gas-liquid separator 42, the outlet of the regenerated gas expander 43 is connected to the condensate and other post-treatment systems, and the regenerated gas expander 43 is also connected to the heat pump compressor 21 and drives the heat pump compressor 21 to do work.

[0030] In the above-mentioned high-temperature steam heat pump system, the refrigerant is an environmentally friendly high-temperature heat pump working fluid such as R1233zd(E) and R1336mzz(Z).

[0031] In the same system, for a 50,000-ton / year carbon capture project, after being put into operation, the 32,900 Nm³ after the desulfurization tower 3The flue gas, at a temperature of 60℃, first enters the lower part of the scrubbing tower 31, where it is cooled to 40℃ by water washing and then discharged from the top of the scrubbing tower 31. Subsequently, under the action of the induced draft fan 311, it enters the lower part of the absorption tower 32, where it is sprayed downwards by a 175m³ of gas. 3 After the lean liquid has fully reacted and removed CO2, it is discharged from the top of the absorption tower 32. The lean liquid that has absorbed CO2 becomes rich liquid, and the rich liquid at 65°C flows out from the bottom of the absorption tower 32. After being pressurized by the rich liquid pump 52, it enters the lean-rich liquid heat exchanger 50 and is preheated to 98°C by the lean liquid. Then it enters the upper part of the regeneration tower 33. In the steam reboiler 10, 2.1t / h, 0.35MPa, 140°C low-pressure steam (flow rate only 30% of the original) supplied externally enters from the main inlet 412 of the ejector 41. It mixes with the regeneration mixed gas (6.25t / h CO2, 1.4t / h steam, temperature about 108°C, pressure about 0.18MPa) ejected from the top of the regeneration tower 33 by the auxiliary inlet 411 of the ejector 41. After mixing, a mixed gas at 0.28MPa and 119°C is formed at the outlet of the ejector 41. The mixed gas enters the second tube side of the steam reboiler 10 to heat the lean liquid outside the tubes (shell side). All the water vapor is condensed, and all the latent heat is recovered. After the condensate is recovered, it becomes CO2 at 0.26 MPa and 110°C. After passing through the gas-liquid separator 42, it enters the regenerated gas expander 43. Through its own expansion, it drives the heat pump compressor 21 to do work and complete the cooling process (cooling to 40°C). Then it goes to the liquefaction and other post-treatment systems.

[0032] Simultaneously, the 127°C, 1.72MPa (condensing temperature 124°C) R1233zd(E) vapor from the outlet of the heat pump compressor 21 enters the first tube side of the reboiler 10 to synchronously heat the lean liquid outside the tubes (shell side), and then becomes liquid R1233zd(E) at 1.7MPa and 110°C. After entering the expansion valve 23, it is de-heated and depressurized, and then becomes a gas-liquid two-phase mixture. It then enters the evaporator 22 on the cold side to absorb heat from the lean liquid on the hot side and evaporates, becoming a gas at 74°C and 0.5MPa (evaporation temperature 69°C). Finally, it enters the heat pump compressor 21, thus completing one cycle.

[0033] For the shell side of the reboiler 10, the 108°C lean liquid from the bottom of the regeneration tower 33 flows through the shell side of the reboiler 10. After being heated by various media in the tube side, it generates 120°C lean liquid steam, which is then sent to the lean liquid collection point at the bottom of the regeneration tower 33. The rich liquid in the regeneration tower 33 decomposes CO2 under the heating of the high-temperature lean liquid steam and is discharged from the top of the regeneration tower 33. The lean liquid steam condenses back into lean liquid and returns to the bottom of the regeneration tower 33. The lean liquid from the lean liquid outlet 332 at the bottom of the regeneration tower 33 is cooled from 108°C to 80°C by the lean-rich liquid heat exchanger 50. Then, it is pressurized to 0.6MPa by the lean liquid pump 53 and enters the hot side of the evaporator 22, where it is cooled to 72°C. Subsequently, it enters the lean liquid cooler 51 and is further cooled to 40°C by external industrial circulating water before entering the spray section at the top of the absorption tower 32.

[0034] In this embodiment, calculations show that the evaporator of the high-temperature heat pump unit recovers approximately 1.6 MW of heat from the lean liquid. Under this operating condition, the COP of the heat pump unit is approximately 3. At this point, the heat released by the condenser of the heat pump unit is approximately 2.4 MW. Adding the sensible heat of the recovered regeneration gas and its large amount of latent heat of water vapor (approximately 1 MW), this is equivalent to 4.8 t / h of externally supplied water vapor heat. Therefore, the self-heating regeneration supply rate can reach 70%, significantly reducing external regeneration energy consumption.

[0035] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A combined heat and power self-balancing carbon capture system, characterized in that, The system includes a flue gas carbon capture system coupled via a steam reboiler (10), a high-temperature steam heat pump system, and a regenerated gas treatment system. The high-temperature steam heat pump system includes an evaporator (22), a heat pump compressor (21), the first tube side of the steam reboiler (10), and an expansion valve (23) connected in sequence. The first tube side of the steam reboiler (10) acts as a condenser in the circulation of the high-temperature steam heat pump system. The regenerated gas treatment system includes an ejector (41), the second tube side of the steam reboiler (10), a gas-liquid separator (42), and a regenerated gas expander (43) connected in sequence from the regenerated gas outlet (331) at the top of the regeneration tower (33). The shell side of the steam reboiler (10) is connected to the lean liquid at the bottom of the regeneration tower (33) to form a shell-side circulation. The regenerated gas expander (43) is also connected to the heat pump compressor (21) and drives the heat pump compressor (21) to do work. In the flue gas carbon capture system, the lean liquid at the bottom of the regeneration tower (33) flows out from the lean and rich liquid heat exchanger (50), first enters the hot side of the evaporator (22), and then enters the spray section at the top of the absorption tower (32) from the lean liquid cooler (51).

2. The combined heat and power self-balancing carbon capture system as described in claim 1, characterized in that, In the flue gas carbon capture system, the low-temperature rich liquid outlet at the bottom of the absorption tower (32) is connected to the reflux section at the top of the regeneration tower (33) in sequence through the rich liquid pump (52) and the lean-rich liquid heat exchanger (50). The high-temperature lean liquid outlet at the bottom of the regeneration tower (33) is connected to the spray section at the top of the absorption tower (32) in sequence through the lean-rich liquid heat exchanger (50), the lean liquid pump (53), the hot side of the evaporator (22), and the lean liquid cooler (51).

3. The combined heat and power self-balancing carbon capture system as described in claim 1, characterized in that, The regeneration tower (33) has a regeneration gas outlet (331) at the top connected to the auxiliary inlet (411) of the ejector, and the ejector has a main inlet (412) connected to the external water supply steam pipeline (60).

4. The combined heat and power self-balancing carbon capture system as described in claim 1, characterized in that, The ejector (41) and the gas-liquid separator (42) are respectively connected to the second tube inlet (131) and the second tube outlet (132) of the steam reboiler (10). A condensate recovery pipeline (44) is also provided between the second tube outlet (132) of the steam reboiler (10) and the gas-liquid separator (42).

5. A combined heat and power self-balancing carbon capture system as described in claim 1, characterized in that, The refrigerant of the high-temperature steam heat pump system is R1233zd(E) or R1336mzz(Z).

6. The combined heat and power self-balancing carbon capture system as described in claim 1, characterized in that, In the high-temperature steam heat pump system, the condensation temperature of the refrigerant in the first tube of the steam reboiler (10) is ≥120℃, and the evaporation temperature is ≤ the lean liquid outlet temperature of the evaporator (22).

7. A combined heat and power self-balancing carbon capture system as described in claim 1, characterized in that, The lean liquor is cooled to ≤40°C in the lean liquor cooler (51) before entering the spray section at the top of the absorption tower (32).

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