A carbon dioxide capture system

Abstract

The present invention discloses a carbon dioxide capture system comprising an absorption tower, a desorption tower, and a Rankine cycle system. The desorption tower is equipped with a precipitated gas discharge pipeline, and rich and lean liquid delivery pipelines are provided between the absorption tower and the desorption tower. The Rankine cycle system comprises a turbine generator set, a condenser, a working fluid delivery pump, a heat recovery heat exchanger, and an evaporator. The turbine generator set, condenser, working fluid delivery pump, heat recovery heat exchanger, and evaporator are connected by the working fluid delivery pipeline to form a thermodynamic cycle. The condenser is located in the rich liquid delivery pipeline, the heat recovery heat exchanger is located in the precipitated gas discharge pipeline, and the evaporator is located in the lean liquid delivery pipeline. This scheme uses the working fluid of the Rankine cycle system as the heat medium, transferring heat that cannot be used for power generation to the rich liquid to be heated, thereby recovering most of the low-grade waste heat and achieving cascade energy utilization. By utilizing the Rankine cycle to utilize the residual and waste heat after desorption, low-grade heat is converted into high-grade electricity.

Description

Technical Field

[0001] The present invention is used in the field of carbon dioxide capture, and in particular relates to a carbon dioxide capture system. Background Art

[0002] Fossil fuels (coal, oil, and natural gas) will likely remain in the energy supply system in the short term. To achieve carbon reduction goals, a viable technical approach is to deploy CCS systems in fossil fuel processes. Currently, the classic chemical absorption CO2 capture process consists of two key components: an absorption tower and a desorption tower. These components are supplemented by an amine solution heat exchanger, a reboiler (amine solution desorption heater), and various pumps and vessels to form a complete process system.

[0003] The absorption tower is where heat and mass transfer between CO2 and the absorption liquid takes place. Gaseous CO2 reacts with the absorption liquid (lean liquid) to form a new compound (rich liquid). The decomposition tower decomposes the resulting compound (rich liquid) into CO2 and absorption liquid (lean liquid) through heating and other material methods. The CO2 enters the subsequent purification, dehydration, and compression processes, and the absorption liquid (lean liquid) is recycled to the absorption tower for continued use.

[0004] Since the decomposition of CO2-rich compounds (rich liquid) requires a lot of heat, reducing the decomposition heat and recovering this waste heat as much as possible are the main measures to reduce energy consumption of the system.

[0005] The main technical solutions for recycling analytical towers currently include:

[0006] 1) Heat exchangers for the lean and rich liquids are installed to recover the physical heat from the lean liquid after heating and desorption, which is then used to preheat the rich liquid before desorption, thereby reducing the amount of new heat required for desorption. However, heat exchangers have poor heat transfer properties. On the one hand, they cannot fully recover waste heat, and on the other hand, the lean liquid is not completely cooled. Therefore, a second cooler must be installed before returning the lean liquid to the absorption tower.

[0007] 2) New proposals consider using the heat from the deionized lean liquid for heating or power generation. Traditional processes focus solely on heat conservation, so deionizing towers are designed to operate at the lowest possible deionizing temperature (80-105°C) to minimize heating steam consumption. Consequently, the waste heat from the deionized lean liquid is of low quality (temperature), limiting its potential applications and value. Furthermore, the thermal cycle efficiency is extremely low when used to heat steam for power generation.

[0008] 3) The waste heat is absorbed by the heat pump and used as the input heat of the analysis tower to replace part of the heating steam used for analysis.

[0009] Disadvantages of existing technology:

[0010] Existing technologies disconnect carbon capture from subsequent compression, focusing excessively on energy consumption during the adsorption-desorption phase while completely ignoring the needs of downstream processes. The desorption tower utilizes a lower desorption temperature, which merely reduces the heat required for desorption. However, in the subsequent compression environment, due to the low desorption temperature, the corresponding desorption pressure (the saturation pressure of the solution) is also relatively low. Consequently, the compressor in the downstream process needs to have a larger volumetric flow rate and pressure ratio to achieve the final CO2 delivery pressure.

[0011] Due to the low desorption temperature and the fact that the lean and rich liquid heat exchangers do not allow the rich liquid to exchange heat with the desorbed CO2, the heat carried by the high-purity CO2 discharged from the desorption tower is essentially unused and is instead directly cooled by cooling water, with the heat being discharged into the environment along with the cooling water.

[0012] Heat pumps can recover low-grade (temperature) heat, but if the temperature of the desorption tower remains constant, the pressure of the high-purity CO2 discharged from the desorption tower also remains constant, and this still fails to reduce the energy consumption required for downstream CO2 compression. Heat pumps essentially use high-grade energy (electricity or high-parameter steam) to recover low-grade heat. The resulting heat is slightly higher than the low-grade heat, failing to achieve a fundamental energy-saving effect. Summary of the Invention

[0013] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a carbon dioxide capture system.

[0014] The technical solution adopted by the present invention to solve its technical problem is:

[0015] A carbon dioxide capture system comprises an absorption tower, a desorption tower and a Rankine cycle system, wherein the desorption tower is provided with a precipitated gas discharge pipeline, and a rich liquid delivery pipeline and a lean liquid delivery pipeline are provided between the absorption tower and the desorption tower. The rich liquid delivery pipeline is provided with a rich liquid pump, and the lean liquid delivery pipeline is provided with a lean liquid pump. The Rankine cycle system comprises a turbine generator set, a condenser, a working fluid delivery pump, a heat recovery heat exchanger and an evaporator. The turbine generator set, the condenser, the working fluid delivery pump, the heat recovery heat exchanger and the evaporator are connected via the working fluid delivery pipeline to form a thermodynamic cycle. The condenser is provided on the rich liquid delivery pipeline, the heat recovery heat exchanger is provided on the precipitated gas discharge pipeline, and the evaporator is provided on the lean liquid delivery pipeline.

[0016] In combination with the above-mentioned implementation methods, in some implementation methods, a rich liquid heater is provided on the rich liquid delivery pipeline, and the working fluid delivery pipeline includes an exhaust pipe, a pump front pipe, a pump back pipe, a hot working fluid pipe, a cold working fluid pipe and a main steam pipe. The exhaust pipe is connected between the turbine generator set and the condenser, the pump front pipe is connected between the condenser and the working fluid delivery pump, the pump back pipe is connected between the working fluid delivery pump and the heat recovery heat exchanger, the hot working fluid pipe is connected between the heat recovery heat exchanger and the rich liquid heater, the cold working fluid pipe is connected between the rich liquid heater and the evaporator, and the main steam pipe is connected between the evaporator and the turbine generator set.

[0017] In combination with the above implementations, in some implementations, a reboiler is further included, and the rich liquid delivery pipeline flows through the condenser, the rich liquid heater and the reboiler in sequence and then is connected to the rich liquid spraying device of the decomposition tower.

[0018] In combination with the above implementations, in some implementations, a first filler is provided in the desorption tower below the rich liquid spraying device.

[0019] In combination with the above implementations, in some implementations, a steam-water separator is provided on the precipitated gas discharge pipeline downstream of the heat recovery heat exchanger, and the steam-water separator is connected to the condensate spraying device of the desorption tower through a condensate delivery pipeline.

[0020] In combination with the above implementations, in some implementations, a second filler is provided in the desorption tower below the condensed water spraying device.

[0021] In combination with the above implementations, in some implementations, a gas cooler is provided on the precipitated gas discharge pipeline between the heat recovery heat exchanger and the steam-water separator.

[0022] In combination with the above implementations, in some implementations, a lean liquid cooler is provided on the lean liquid delivery pipeline.

[0023] In combination with the above implementations, in some implementations, the Rankine cycle system uses an organic refrigerant as a thermodynamic cycle working fluid.

[0024] In combination with the above implementations, in some implementations, the Rankine cycle system uses water as the thermodynamic cycle working medium.

[0025] One of the above technical solutions has at least one of the following advantages or beneficial effects:

[0026] The laws of thermodynamics reveal that when low-grade heat is converted into high-grade mechanical energy (electricity), waste heat is inevitably released into the environment. This solution uses the Rankine cycle system's working fluid as the heat medium, transferring the heat that the system cannot use for power generation to the rich liquid to be heated. This recovers most of the low-grade waste heat and achieves cascaded energy utilization.

[0027] Using the Rankine cycle fluid as the intermediate heat transfer medium, heat transfer and waste heat recovery are accomplished in each heat exchanger between the lean liquid, rich liquid, and CO2 gas. In both the condenser (where the Rankine cycle fluid condenses) and the evaporator (where the Rankine cycle fluid evaporates), the Rankine cycle fluid transfers heat via phase change, effectively improving heat transfer efficiency. In the heat recovery heat exchanger, the water contained in the CO2 gas undergoes a phase change (condensation) during heat transfer, also partially improving heat transfer efficiency.

[0028] The Rankine cycle system can adjust its capacity as needed. In any operating condition, the flow of the working fluid in the Rankine cycle system can be adjusted through the working fluid delivery pump, and the power generation of the turbine generator set can be adjusted to adapt to the situation where the cooling and heating heat of the absorption tower and the desorption tower are not equal.

[0029] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0031] Figure 1 It is a structural diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0032] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.

[0033] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0034] In the present invention, "several" means one or more, "multiple" means more than two, "greater than," "less than," "exceeds," etc. are understood to exclude the number itself; "above," "below," "within," etc. are understood to include the number itself. In the description of the present invention, the use of "first" or "second" is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0035] In the present invention, unless otherwise expressly defined, terms such as "disposed," "installed," and "connected" should be interpreted broadly. For example, they may refer to direct connection or indirect connection through an intermediate medium; fixed connection or detachable connection or integral molding; mechanical connection or electrical connection or mutual communication; and internal connection between two components or interaction between two components. Those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0036] At present, the chemical absorption CO2 capture process and the downstream compression process are not coordinated together for overall energy saving considerations. Therefore, it is necessary to appropriately adjust the design parameters of the analysis tower according to the process characteristics to obtain the best overall energy saving benefits.

[0037] Increasing the operating temperature of the desorption tower increases the corresponding saturation pressure within the tower, resulting in a higher initial pressure for the output CO2. This, in turn, reduces the specifications and power consumption of the downstream process compressors, effectively replacing some high-quality electricity (compressor power consumption) with lower-quality heat (steam). Although the total energy consumption of the carbon capture system (the simple sum of various energy sources) varies little, according to the laws of thermodynamics, the conversion of heat to electricity is always less than 100%. Currently, mainstream thermal engine technology only achieves a thermoelectric conversion efficiency of 20% to 60%, meaning that for every unit of electricity saved, two to five units of heat are saved, resulting in a significant reduction in primary energy (coal, natural gas) consumption.

[0038] After increasing the operating temperature and pressure of the analysis tower, the quality of recoverable heat is also improved accordingly. Therefore, it is necessary to adjust the waste heat recovery process from simple heat recovery to comprehensive recovery of mechanical energy (power generation) and heat.

[0039] This solution mainly consists of two innovations. The first is to increase the desorption temperature and the corresponding operating pressure, thereby reducing the cost and operating power consumption of gas compression in the downstream process. The second is that due to the higher operating temperature of the absorption tower, the Rankine cycle system is used to convert high-grade heat into mechanical work or electrical energy, and the remaining heat is recovered by heat exchange.

[0040] For details, see Figure 1The embodiment of the present invention provides a carbon dioxide capture system, including an absorption tower 100, a desorption tower 200 and a Rankine cycle system. The desorption tower 200 is provided with a precipitated gas discharge pipeline 203. A rich liquid delivery pipeline 101 and a lean liquid delivery pipeline 201 are provided between the absorption tower 100 and the desorption tower 200. A rich liquid pump 110 is provided on the rich liquid delivery pipeline 101. The rich liquid pump 110 is used to pump the rich liquid that absorbs CO2 from the absorption tower 100 to the desorption tower 200. A lean liquid pump 210 is provided on the lean liquid delivery pipeline 201. The lean liquid pump 210 is used to pump the lean liquid after desorption from the absorption tower 100 to the desorption tower 200. The desorption tower 200 is pumped to the absorption tower 100. The Rankine cycle system includes a turbine generator set 300, a condenser 120, a working fluid delivery pump 310, a heat recovery heat exchanger 250 and an evaporator 220. The turbine generator set 300, the condenser 120, the working fluid delivery pump 310, the heat recovery heat exchanger 250 and the evaporator 220 are connected through a working fluid delivery pipeline to form a thermodynamic cycle. The condenser 120 is arranged on the rich liquid delivery pipeline 101, the heat recovery heat exchanger 250 is arranged on the precipitated gas discharge pipeline 203, and the evaporator 220 is arranged on the lean liquid delivery pipeline 201.

[0041] The process principle of this scheme:

[0042] 1) The CO2 absorption process for flue gas in absorption tower 100 is similar to conventional technology and will not be described further. The rich liquid exiting absorption tower 100 is pumped by rich liquid pump 110 and receives exhaust steam from the Rankine cycle system in condenser 120. It absorbs heat from the Rankine cycle working fluid, condensing it into liquid and heating the rich liquid accordingly. After being heated to a preset temperature, it is distributed in desorption tower 200. The rich liquid decomposes at a higher temperature, releasing CO2, while the lean liquid falls to the bottom of desorption tower 200.

[0043] 2) The lean liquid is output through the lean liquid pump 210 and first passes through the evaporator 220, where it transfers heat to the working medium of the Rankine cycle system and evaporates it from liquid to gas, and the lean liquid temperature drops accordingly.

[0044] The CO2 discharged from the desorption tower 200 passes through the heat recovery heat exchanger 250, releasing a portion of the heat to the working fluid of the Rankine cycle system.

[0045] 3) This solution utilizes a Rankine cycle combined with heat exchange to recover heat from the desorption tower 200. The thermal cycle fluid serves as the heat exchange medium between the lean and rich liquids, eliminating the need for direct heat exchange equipment between the rich and lean liquid pipelines. The Rankine cycle fluid vapor flows from the fluid pipeline into the turbine generator set 300 to generate power. It then flows through the fluid pipeline into the condenser 120, releasing latent heat and transferring any remaining heat to the cool rich liquid. The condensed fluid then flows through the fluid pump 310 into the heat recovery heat exchanger 250, recovering the waste heat from the high-temperature CO2 gas. Finally, the Rankine cycle fluid enters the evaporator 220, absorbing the residual heat from the lean liquid and evaporating into a gaseous state, returning to the turbine generator set 300 to generate power.

[0046] 4) The flow rate of the circulating fluid in the Rankine cycle system can be increased or decreased as needed to adjust power generation output and the amount of heat exchanged between the lean and rich liquids to achieve system balance. For example, increasing the flow rate will increase the amount of heat transferred through the various heat exchangers, but this will also cause the temperature of the Rankine cycle fluid to drop, reducing power generation efficiency. Simulation and optimization algorithms can be used to select optimal operating parameters and can also be used as a regulatory measure to accommodate unequal cooling and heating heat outputs in the absorption tower 100 and desorption tower 200.

[0047] The embodiments of the present invention have the following advantages:

[0048] The laws of thermodynamics reveal that when low-grade heat is converted into high-grade mechanical energy (electricity), waste heat is inevitably released into the environment. This solution uses the Rankine cycle system's working fluid as the heat medium, transferring heat that the system cannot use for power generation to the rich liquid to be heated. This recovers most of the low-grade waste heat and achieves cascade energy utilization. By utilizing the Rankine cycle to utilize the residual and waste heat after analysis, low-grade heat is converted into high-grade electricity.

[0049] Using the Rankine cycle fluid as the intermediate heat transfer medium, heat transfer and waste heat recovery between lean liquid, rich liquid, and CO2 gas are accomplished in each heat exchanger, replacing the traditional direct heat exchange method between lean and rich liquids. In the condenser 120 (where the Rankine cycle fluid condenses) and evaporator 220 (where the Rankine cycle fluid evaporates), the Rankine cycle fluid transfers heat via phase change, effectively improving heat exchange efficiency. In the heat recovery heat exchanger 250, the water contained in the CO2 gas undergoes a phase change (condensation) during heat transfer, also locally improving heat exchange efficiency.

[0050] The capacity of the Rankine cycle system can be adjusted as needed. In any operating condition, the flow rate of the working fluid in the Rankine cycle system can be adjusted by the working fluid delivery pump 310, and the power generation of the turbine generator set 300 can be adjusted to adapt to the situation where the cooling and heating heat of the absorption tower 100 and the desorption tower 200 are not equal.

[0051] In some embodiments, see Figure 1 A rich liquid heater 130 is provided on the rich liquid delivery pipeline 101, and the working fluid delivery pipeline includes an exhaust steam pipeline 302, a pump-front pipeline 311, a pump-back pipeline 312, a hot working fluid pipeline 313, a cold working fluid pipeline 314 and a main steam pipeline 301. The working fluid delivery pipeline is arranged as follows: the exhaust steam pipeline 302 is connected between the turbine generator set 300 and the condenser 120, the pump-front pipeline 311 is connected between the condenser 120 and the working fluid delivery pump 310, the pump-back pipeline 312 is connected between the working fluid delivery pump 310 and the heat recovery heat exchanger 250, the hot working fluid pipeline 313 is connected between the heat recovery heat exchanger 250 and the rich liquid heater 130, the cold working fluid pipeline 314 is connected between the rich liquid heater 130 and the evaporator 220, and the main steam pipeline 301 is connected between the evaporator 220 and the turbine generator set 300.

[0052] For further information, see Figure 1 The carbon dioxide capture system also includes a reboiler 240. The rich liquid delivery pipeline 101 flows through the condenser 120, the rich liquid heater 130 and the reboiler 240 in sequence and then connects to the rich liquid spray device 241 of the desorption tower 200. In the traditional scheme, the reboiler 240 receives the lean liquid that has been initially desorbed from the spray layer, and after reheating, it is sent back to the liquid storage space at the bottom of the desorption tower 200 without passing through the packing layer. The embodiment of the present invention has been improved according to the process characteristics. The reboiler 240 receives the undesorbed rich liquid, and after heating, it is sent to the packing of the desorption tower 200 through the rich liquid spray device 241. After the packing is fully desorbed and CO2 is desorbed, it falls to the bottom of the desorption tower 200.

[0053] In this embodiment, the rich liquid exiting the absorption tower 100 is transported by the rich liquid pump 110. It first receives exhaust steam from the Rankine cycle system in the condenser 120, where it absorbs heat from the Rankine cycle working fluid, condensing the working fluid into liquid and heating the rich liquid accordingly. The rich liquid is then heated a second time in the rich liquid heater 130 and then a third time in the reboiler 240 to a preset temperature. This preset desorption temperature is higher than conventional technologies (80-110°C). Based on the absorbent's maximum resistance to oxidation or thermal decomposition, it is considered to be 150-185°C. If a more temperature-resistant absorbent becomes available in the future, a temperature of 190-200°C may be considered.

[0054] The first two heating steps of the rich liquid are passive and require no adjustment. The third heating step is controlled by adjusting the steam flow rate. After reaching a preset temperature, the rich liquid is evenly distributed over the packing of the desorption tower 200 through the rich liquid spray device 241. The rich liquid decomposes at a higher temperature, releasing CO2, while the lean liquid falls to the bottom of the desorption tower 200.

[0055] This solution increases the operating temperature of the desorption tower 200, which in turn increases the saturation pressure and the output product gas pressure. This creates the prerequisite for reducing the cost and power consumption of the downstream CO2 compression process. The temperature of the desorbed lean liquid and CO2 is also significantly higher than that of conventional technologies. According to the laws of thermodynamics, under the same cold-end ambient temperature, the higher the initial working fluid temperature, the higher the heat-to-work conversion efficiency. Therefore, increasing the desorption operating pressure also increases the waste heat temperature, improving the utilization and economic efficiency of thermal energy for power generation.

[0056] It is understandable that the rich liquid heater 130 may not be provided, and the required heating share may be replaced by the reboiler 240 .

[0057] In some embodiments, see Figure 1 In order to promote gas-liquid mass transfer, a first filler is provided below the rich liquid spraying device 241 in the analysis tower 200. The first filler can be a plastic filler or a steel filler.

[0058] In some embodiments, see Figure 1 A steam-water separator 270 is provided on the precipitated gas discharge pipeline 203 downstream of the heat recovery heat exchanger 250 , and the steam-water separator 270 is connected to the condensate spraying device of the desorption tower 200 through a condensate delivery pipeline.

[0059] In order to promote gas-liquid mass transfer, a second filler is provided below the condensed water spraying device in the desorption tower 200 .

[0060] Furthermore, a gas cooler 260 is provided on the precipitated gas discharge pipeline 203 between the heat recovery heat exchanger 250 and the steam-water separator 270 .

[0061] Combine Figure 1 The CO2 discharged from the analysis tower 200 first passes through the heat recovery heat exchanger 250 to release part of the heat to the working fluid of the Rankine cycle system, and then passes through the gas cooler 260 for complete final cooling to precipitate water vapor in the CO2 gas; after the water vapor condenses, it is collected in the steam-water separator 270 and recovered through the condensed water delivery pipeline.

[0062] In some embodiments, see Figure 1 A lean liquid cooler 230 is provided on the lean liquid delivery pipeline 201. The lean liquid is pumped out by the lean liquid pump 210 and first passes through the evaporator 220, where it transfers heat to the Rankine cycle working fluid, evaporating it from liquid to gas, causing the lean liquid temperature to drop accordingly. The lean liquid is then further cooled by the lean liquid cooler 230, ensuring that the lean liquid temperature does not exceed 45°C before returning to the absorption tower 100.

[0063] The lean liquid cooler 230 and the gas cooler 260 may not need to be provided in certain working conditions, and the required design temperature can be achieved only through the circulation and heat transfer of the working fluid in the Rankine cycle system.

[0064] In some embodiments, the Rankine cycle system uses an organic refrigerant as a thermodynamic cycle working fluid, namely an organic Rankine cycle (ORC), which uses a low-boiling point organic liquid (refrigerant) as a thermodynamic cycle working fluid to replace water and water vapor for thermodynamic circulation. The principle is roughly similar to that of a traditional steam turbine power station, but the thermal characteristics are different in the medium and low temperature range (90-200°C), and the theoretical cycle efficiency is slightly higher than that of the water-water vapor system.

[0065] It is understandable that the Rankine cycle system also uses water as the thermodynamic cycle working fluid, that is, the conventional steam Rankine cycle (SRC). The technical concept is the same as that of ORC, but the thermoelectric conversion efficiency is different.

[0066] Throughout this specification, references to terms such as "example," "embodiment," or "some embodiments" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0067] Of course, the invention is not limited to the above-mentioned embodiments. Those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A carbon dioxide capture system, characterized in that: It includes an absorption tower, an analysis tower and a Rankine cycle system, the analysis tower is provided with a precipitated gas discharge pipeline, a rich liquid delivery pipeline and a lean liquid delivery pipeline are set between the absorption tower and the analysis tower, the rich liquid delivery pipeline is provided with a rich liquid pump, the lean liquid delivery pipeline is provided with a lean liquid pump, the Rankine cycle system includes a turbine generator set, a condenser, a working fluid delivery pump, a heat recovery heat exchanger and an evaporator, the turbine generator set, the condenser, the working fluid delivery pump, the heat recovery heat exchanger and the evaporator are connected through the working fluid delivery pipeline to form a thermodynamic cycle, the condenser is arranged on the rich liquid delivery pipeline, the heat recovery heat exchanger is arranged on the precipitated gas discharge pipeline, the evaporator is arranged on the lean liquid delivery pipeline. A liquid delivery pipeline, a rich liquid heater is provided on the rich liquid delivery pipeline, the working fluid delivery pipeline includes an exhaust pipe, a pump front pipe, a pump rear pipe, a hot working fluid pipe, a cold working fluid pipe and a main steam pipe, the exhaust pipe is connected between the turbine generator set and the condenser, the pump front pipe is connected between the condenser and the working fluid delivery pump, the pump rear pipe is connected between the working fluid delivery pump and the heat recovery heat exchanger, the hot working fluid pipe is connected between the heat recovery heat exchanger and the rich liquid heater, the cold working fluid pipe is connected between the rich liquid heater and the evaporator, and the main steam pipe is connected between the evaporator and the turbine generator set.

2. The carbon dioxide capture system according to claim 1, characterized in that It also includes a reboiler, and the rich liquid delivery pipeline flows through the condenser, the rich liquid heater and the reboiler in sequence and then is connected to the rich liquid spraying device of the analytical tower.

3. The carbon dioxide capture system according to claim 2, characterized in that A first filler is provided below the rich liquid spraying device in the analytical tower.

4. The carbon dioxide capture system according to claim 1, wherein: A steam-water separator is provided on the precipitated gas discharge pipeline downstream of the heat recovery heat exchanger, and the steam-water separator is connected to the condensate spraying device of the analytical tower through a condensate delivery pipeline.

5. The carbon dioxide capture system according to claim 4, characterized in that A second filler is provided in the decomposition tower below the condensed water spraying device.

6. The carbon dioxide capture system according to claim 4, characterized in that A gas cooler is provided on the precipitated gas discharge pipeline between the heat recovery heat exchanger and the steam-water separator.

7. The carbon dioxide capture system according to claim 1, wherein: A lean liquid cooler is provided on the lean liquid delivery pipeline.

8. The carbon dioxide capture system according to claim 1, wherein: The Rankine cycle system uses an organic refrigerant as a thermodynamic cycle working medium.

9. The carbon dioxide capture system according to claim 1, wherein: The Rankine cycle system uses water as a thermodynamic cycle working medium.

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