Carbon capture and compression system based on comprehensive utilization of waste heat and LNG cold energy

Abstract

The utility model provides a carbon capture and compression system based on comprehensive utilization of waste heat and LNG (Liquefied Natural Gas) cold energy. The carbon capture and compression system comprises a flue gas cooler, an absorption tower, a rich liquid diverter, a lean and rich liquid heat exchanger, a regenerated gas heat exchanger, a flash steam compressor, a regeneration tower, a reboiler, a two-stage compressor, a multi-stream heat exchanger and a carbon dioxide condenser. A pregnant solution diverter and a regenerated gas heat exchanger are used for recycling waste heat of regenerated gas at the top of the regeneration tower to heat pregnant solution, and sensible heat and latent heat of absorbent regeneration are reduced; the cold energy of liquefied natural gas can be used for liquefying carbon dioxide under intermediate pressure, the compression stage number and compression power consumption of the carbon dioxide are reduced, the multi-stream heat exchanger is used for recovering the compression heat of the carbon dioxide for heating condensate water, the using amount of latent heat and cooling water is further reduced, and the energy consumption is reduced. And full recovery of waste heat in a chemical absorption method carbon dioxide capture and compression system and efficient utilization of liquefied natural gas cold energy are achieved, and the energy utilization efficiency and economical efficiency of the system are improved.

Description

Technical Field

[0001] This utility model belongs to the field of carbon dioxide capture and compression by chemical absorption method, and particularly relates to the field of waste heat recovery and liquefied natural gas cold energy utilization generated during the capture process. In particular, it relates to a carbon capture and compression system based on the comprehensive utilization of waste heat and LNG cold energy. Background Technology

[0002] The massive emission of greenhouse gases is one of the main causes of global warming, with carbon dioxide contributing approximately 60% to this increase. Carbon dioxide primarily originates from the use of fossil fuels, and its unchecked emission into the environment will severely exacerbate the greenhouse effect. Chemical absorption, represented by amine solutions, is a relatively mature and commercially viable carbon dioxide capture technology; however, it suffers from high initial investment, high capture energy consumption, and high compression power consumption. The regeneration energy consumption of chemical absorption carbon dioxide capture technology consists of three parts: reaction heat, sensible heat, and latent heat. The magnitude of the reaction heat is mainly determined by the type of absorbent. Sensible heat is used to heat the rich absorbent solution, raising its temperature to the reboiler temperature. Latent heat is mainly used to heat the solution to generate stripping steam and to raise the temperature of the reflux condensate at the top of the regeneration tower to the rich solution temperature. Furthermore, carbon dioxide needs to be liquefied before being transported to storage or utilization sites for pipeline transport. This typically involves multi-stage compression and intercooling to increase the pressure to around 150 bar, resulting in very high compression power consumption. On the other hand, chemical absorption carbon dioxide capture and compression systems generate a large amount of low-temperature waste heat, such as the cooling heat of the gas at the top of the regeneration tower, the superheat of the low-pressure extraction steam, the cooling heat of the reboiler condensate, and the intermediate cooling heat during carbon dioxide compression. This heat is difficult to recover using conventional methods, resulting in low energy utilization efficiency. Therefore, effectively recovering the system's waste heat and reducing energy losses during the utilization process is key to achieving high efficiency and energy saving in carbon dioxide capture systems.

[0003] As the fastest-growing primary energy source, natural gas boasts advantages such as high combustion efficiency and low greenhouse gas emissions. Liquefied natural gas (LNG), as the liquid form of natural gas, has a temperature of -162°C at atmospheric pressure. Before use, it must absorb heat and vaporize into natural gas, releasing approximately 830 kJ / kg of cold energy in the process. Using seawater as a heat source would cause low-temperature pollution of the ocean and waste of high-grade cold energy. Currently, there are few reports on the integrated utilization of waste heat and LNG cold energy in chemical absorption carbon dioxide capture and compression technologies, and detailed and in-depth discussions are lacking, indicating significant research potential.

[0004] Lu Shijian et al. disclosed a chemical absorption carbon dioxide capture system based on waste heat recovery and utilization in Chinese invention patent CN110152457A. The system uses two lean and rich liquid heat exchangers and a heat pump system to recover the system's waste heat. The system is relatively complex, increases the number of equipment, and only recovers the heat of the gas discharged from the top of the desorption tower. A large amount of other waste heat, such as superheated steam extraction and carbon dioxide compression heat, is wasted. In addition, the recovery of liquefied natural gas cold energy is not considered, and the waste heat utilization is insufficient. Utility Model Content

[0005] In order to at least solve one of the problems existing in the prior art, this utility model proposes a chemical absorption carbon dioxide capture and compression system based on the comprehensive utilization of waste heat and liquefied natural gas cold energy. It can effectively integrate the low-temperature waste heat existing in the system and realize the efficient utilization of liquefied natural gas cold energy, improve the energy utilization efficiency of the system, and reduce the energy consumption of the carbon dioxide capture and compression process.

[0006] To achieve the objectives of this utility model, a chemical absorption carbon dioxide capture and compression system based on the comprehensive utilization of waste heat and liquefied natural gas (LNG) cold energy is proposed. The system includes a flue gas cooler, an absorption tower, a rich liquid pump, a rich liquid distributor, a lean-rich liquid heat exchanger, a regeneration tower, a reboiler, a regenerated gas heat exchanger, a pressure reducing valve, a flash tank, a flash steam compressor, a lean liquid pump, a back-pressure turbine, a mixer, a condensate distributor, a generator, a magnetic coupler, a lean liquid cooler, a lean liquid mixer, a lean liquid pressure reducing valve, a multi-stream heat exchanger, a two-phase separator, a first-stage compressor, a first-stage gas-liquid separator, a second-stage compressor, a second-stage gas-liquid separator, a carbon dioxide condenser, an LNG storage tank, an LNG booster pump, and a carbon dioxide booster pump.

[0007] After being cooled by the flue gas cooler, the high-temperature flue gas enters the absorption tower from the bottom and comes into countercurrent contact with the lean absorbent sprayed from the top of the absorption tower. A chemical reaction occurs, and the carbon dioxide in the flue gas reacts with the absorbent to form carbamate. The purified gas, with the carbon dioxide removed, is discharged from the top of the absorption tower.

[0008] The rich liquid that has absorbed carbon dioxide is divided into two streams by the rich liquid splitter. One stream enters the regeneration gas heat exchanger to recover the heat of the regeneration gas at the top of the regeneration tower, and the other stream enters the lean and rich liquid heat exchanger to recover the heat of the lean liquid. After the temperature rises, it enters the regeneration tower for desorption.

[0009] The low-pressure extraction steam from the power plant has a relatively high pressure and temperature. To prevent absorbent degradation, it first enters the back-pressure turbine to drive the impeller and recover pressure energy before entering the reboiler for heating. A portion of the mechanical energy is converted into electrical energy via a magnetic coupler connected to a generator. After the pressure decreases, the extraction steam mixes with some of the reboiler condensate to recover superheated extraction steam. After the temperature decreases, it enters the reboiler for heating.

[0010] In the reboiler, the rich liquor is heated by low-pressure steam to produce stripping steam, which comes into countercurrent contact with the rich liquor flowing down from above. This heating causes a desorption reaction in the rich liquor, releasing carbon dioxide and carrying a large amount of water vapor, which is then discharged from the top of the regeneration tower. To recover the latent heat of the lean liquor, the high-temperature lean liquor flowing from the bottom of the regeneration tower enters a lean liquor pressure reducing valve to lower the pressure. It then enters a flash tank to flash out the lean liquor vapor. The remaining lean liquor enters a lean-rich liquor heat exchanger to heat the rich liquor. The lean liquor vapor is then pressurized to the regeneration tower pressure by a flash compressor and then fed into the lean-rich liquor heat exchanger to heat the rich liquor, lowering its temperature to the reboiler temperature before it enters the regeneration tower for heating.

[0011] The regenerated gas at the top of the regeneration tower recovers some heat through the regeneration gas heat exchanger and then enters the multi-flow heat exchanger to recover the remaining heat energy. After the temperature drops, it enters the two-phase separator, where the water vapor condenses into condensate and enters the multi-flow heat exchanger to be heated. After the temperature rises, it enters the regeneration tower from the bottom, reducing the latent heat and the flow rate of the make-up water.

[0012] Carbon dioxide carrying water vapor is pressurized by the first-stage compressor and then enters a multi-flow heat exchanger to recover the heat of compression. After its temperature decreases, it enters the first-stage gas-liquid separator to remove condensate. Then, it is compressed to above the triple point pressure by the second-stage compressor to prevent sublimation. After the pressure increases, the carbon dioxide re-enters the multi-flow heat exchanger to recover the heat of compression in the second stage. After cooling down, it enters the second-stage gas-liquid separator to remove the remaining condensate, yielding high-purity carbon dioxide.

[0013] Water vapor-free carbon dioxide enters a carbon dioxide condenser and exchanges heat with liquefied natural gas from the liquefied natural gas storage tank, reducing its temperature below the boiling point. After recovering the cold energy, the liquefied natural gas is vaporized into natural gas for subsequent utilization. Liquid carbon dioxide is pressurized to transportation pressure by a carbon dioxide booster pump and then enters a multi-flow heat exchanger to be heated to transportation temperature before being transported to storage or utilization sites via pipeline.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0015] (1) In the system of this utility model, a portion of the rich liquid is diverted to the regeneration gas heat exchanger to recover the waste heat of the regeneration gas at the top of the regeneration tower, thereby reducing the sensible heat; the lean liquid at the bottom of the regeneration tower is depressurized by the pressure reducing valve and then flashed out as lean liquid vapor. After being pressurized by the flash vapor compressor, the temperature rises and enters the lean-rich liquid heat exchanger to heat the rich liquid. After recovering the heat, the temperature drops to the reboiler temperature and then enters the regeneration tower for heating, thereby reducing the heat load of the reboiler.

[0016] (2) In the system of this utility model, the pressure energy of the low-pressure extracted steam is recovered by the back pressure steam turbine to drive the flash steam compressor, and is converted into electrical energy by the generator, so that the extracted steam is reduced to a suitable pressure and then enters the reboiler for heating, thus realizing cogeneration; the superheat of the reboiler condensate is recovered by mixing the reflux part of the reboiler condensate and the extracted steam, which reduces the amount of gas extracted by the power plant; the waste heat of the regeneration gas at the top of the regeneration tower and the heat of carbon dioxide compression are recovered by the multi-stream heat exchanger to heat the condensate reflux water of the regeneration tower, saving latent heat and makeup water flow.

[0017] (3) In the system of this utility model, the cold energy of liquefied natural gas is recovered and used to liquefy carbon dioxide under intermediate pressure, which greatly reduces the number of compression stages and compression power consumption of carbon dioxide. In addition, after the carbon dioxide is liquefied, it enters the multi-flow heat exchanger to recover the remaining cold energy, which can significantly reduce the amount of cooling water used in the carbon dioxide compression process.

[0018] (4) This utility model effectively recovers the low-temperature waste heat in the carbon dioxide capture and compression process, realizes the efficient utilization of liquefied natural gas cold energy, significantly reduces the regeneration energy consumption and compression power consumption, and greatly improves energy utilization efficiency and economy. Attached Figure Description

[0019] Figure 1 This is a process flow diagram of the carbon dioxide capture and compression system based on the comprehensive utilization of waste heat and liquefied natural gas cold energy in the embodiments of this utility model.

[0020] The reference numerals in the attached figures are explained as follows:

[0021] 1 Absorption Tower

[0022] 101 Absorption Tower First Inlet

[0023] 102 Absorption Tower Second Inlet

[0024] First outlet of 103 absorption tower

[0025] 104 Absorption Tower Second Outlet

[0026] 2 rich liquid pumps

[0027] 201 Rich Liquid Pump Inlet

[0028] 202 Rich Liquid Pump Outlet

[0029] 3 Rich liquid distributor

[0030] 301 Rich Liquid Diverter Inlet

[0031] 302 Rich Liquid Diverter First Outlet

[0032] 303 Rich Liquid Diverter Second Outlet

[0033] 4. Rich and poor liquid heat exchangers

[0034] 401 Lean / Rich Liquid Heat Exchanger First Inlet

[0035] 402 Lean / Rich Liquid Heat Exchanger Second Inlet

[0036] 403 Lean / Rich Liquid Heat Exchanger Third Inlet

[0037] 404 Lean / Rich Liquid Heat Exchanger First Outlet

[0038] 405 Lean / Rich Liquid Heat Exchanger Second Outlet

[0039] 406 Lean / Rich Liquid Heat Exchanger Third Outlet

[0040] 5 Regeneration Towers

[0041] 501 Regeneration Tower First Inlet

[0042] 502 Regeneration Tower Second Inlet

[0043] 503 Regeneration Tower Third Inlet

[0044] 504 Regeneration Tower Fourth Inlet

[0045] 505 Regeneration Tower Fifth Inlet

[0046] 506 Regeneration Tower First Exit

[0047] 507 Regeneration Tower Second Outlet

[0048] 6 Reboilers

[0049] 601 Reboiler First Inlet

[0050] 602 Reboiler Second Inlet

[0051] 603 Reboiler First Outlet

[0052] 604 Reboiler Second Outlet

[0053] 7 Back pressure steam turbine

[0054] 701 Back Pressure Steam Turbine Import

[0055] 702 Back Pressure Steam Turbine Outlet

[0056] 8 mixers

[0057] 801 Mixer First Inlet

[0058] 802 Mixer Second Inlet

[0059] 803 Mixer Outlet

[0060] 9. Condensate Diverter

[0061] 901 Condensate Diverter Inlet

[0062] 902 Condensate Diverter First Outlet

[0063] 903 Condensate Diverter Second Outlet

[0064] 10 Pressure Reducing Valve

[0065] 1001 pressure reducing valve inlet

[0066] 1002 pressure reducing valve outlet

[0067] 11 flash evaporators

[0068] 1101 flash tank import

[0069] 1102 Flash Tank First Outlet

[0070] 1103 Flash Tank Second Outlet

[0071] 12 flash steam compressor

[0072] 1201 Flash Vapor Compressor Import

[0073] 1202 Flash Steam Compressor Outlet

[0074] 13 Rich Liquid Pump

[0075] 1301 Rich Liquid Pump Inlet

[0076] 1302 Rich Liquid Pump Outlet

[0077] 14 Lean Liquid Cooler

[0078] 1401 Lean Liquid Cooler First Inlet

[0079] 1402 Lean Liquid Cooler Second Inlet

[0080] 1403 Lean Liquid Cooler First Outlet

[0081] 1404 Lean Liquid Cooler Second Outlet

[0082] 15 lean liquid mixer

[0083] 1501 Lean Liquid Mixer First Inlet

[0084] 1502 Lean Mixer Second Inlet

[0085] 1503 Lean Solution Mixer Third Inlet

[0086] 1504 lean liquor mixer outlet

[0087] 16 Lean Liquid Pressure Reducing Valve

[0088] 1601 Lean Liquid Pressure Reducing Valve Inlet

[0089] 1602 Lean Liquid Pressure Reducing Valve Outlet

[0090] 17 Regenerated Gas Heat Exchanger

[0091] 1701 Regenerated Gas Heat Exchanger First Inlet

[0092] 1702 Regenerated Gas Heat Exchanger Second Inlet

[0093] 1703 Regenerated Gas Heat Exchanger First Outlet

[0094] 1704 Regenerated Gas Heat Exchanger Second Outlet

[0095] 18-stream heat exchanger

[0096] 1801 Multi-flow Heat Exchanger First Inlet

[0097] 1802 Multi-flow Heat Exchanger Second Inlet

[0098] 1803 Multi-flow Heat Exchanger Third Inlet

[0099] 1804 Multi-flow Heat Exchanger Fourth Inlet

[0100] 1805 Multi-flow Heat Exchanger Fifth Inlet

[0101] 1806 Multi-flow Heat Exchanger Sixth Inlet

[0102] 1807 Multi-flow Heat Exchanger First Outlet

[0103] 1808 Multi-flow Heat Exchanger Second Outlet

[0104] 1809 Multi-flow Heat Exchanger Third Outlet

[0105] 1810 multi-flow heat exchanger, fourth outlet

[0106] 1811 Multi-flow Heat Exchanger Fifth Outlet

[0107] 1812 Multi-flow Heat Exchanger, Sixth Outlet

[0108] 19 Two-phase separator

[0109] 1901 Two-Phase Separator Inlet

[0110] 1902 Two-Phase Separator First Outlet

[0111] 1903 Two-Phase Separator Second Outlet

[0112] 20 First-stage compressor

[0113] 2001 First-stage compressor import

[0114] 2002 First-stage compressor outlet

[0115] 21 First-stage gas-liquid separator

[0116] 2101 First-stage gas-liquid separator inlet

[0117] 2102 First stage gas-liquid separator first outlet

[0118] 2103 First-stage gas-liquid separator, second outlet

[0119] 22 Second-stage compressor

[0120] 2201 Second Stage Compressor Inlet

[0121] 2202 Second-stage compressor outlet

[0122] 23 Second-stage gas-liquid separator

[0123] 2301 Second-stage gas-liquid separator inlet

[0124] 2302 Second-stage gas-liquid separator first outlet

[0125] 2303 Second Stage Gas-Liquid Separator Second Outlet

[0126] 24 CO2 condenser

[0127] 2401 CO2 condenser first inlet

[0128] 2402 CO2 condenser second inlet

[0129] 2403 CO2 condenser first outlet

[0130] 2404 CO2 condenser second outlet

[0131] 25 CO2 booster pump

[0132] 2501 CO2 booster pump inlet

[0133] 2502 CO2 booster pump outlet

[0134] 26 liquefied natural gas storage tanks

[0135] 2601 liquefied natural gas storage tank outlet

[0136] 27 liquefied natural gas booster pump

[0137] 2701 liquefied natural gas booster pump inlet

[0138] 2702 LNG booster pump outlet

[0139] 28 Flue Gas Cooler

[0140] 2801 Flue Gas Cooler First Inlet

[0141] 2802 Flue Gas Cooler Second Inlet

[0142] 2803 Flue Gas Cooler First Outlet

[0143] 2804 Flue Gas Cooler Second Outlet

[0144] 29 generators

[0145] 30 magnetic couplers

[0146] Figure 2 This is a schematic diagram of the carbon dioxide capture and compression system based on the comprehensive utilization of waste heat and liquefied natural gas cold energy according to this utility model.

[0147] Figure 3 This is a schematic diagram of low-pressure steam extraction heat recovery in an embodiment of this utility model. Detailed Implementation

[0148] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0149] The present invention provides a chemical absorption carbon dioxide capture and compression system based on the comprehensive utilization of waste heat and liquefied natural gas cold energy, comprising an absorption tower 1, a rich liquid pump 2, a rich liquid distributor 3, a lean-rich liquid heat exchanger 4, a regeneration tower 5, a reboiler 6, a flash tank 11, a flash steam compressor 12, a lean liquid pump 13, a lean liquid cooler 14, a lean liquid mixer 15, a lean liquid pressure reducing valve 16, a regenerated gas heat exchanger 17, a multi-stream heat exchanger 18, a two-phase separator 19, a first-stage compressor 20, a second-stage compressor 22, a first-stage gas-liquid separator 21, a second-stage gas-liquid separator 23, a carbon dioxide condenser 24, a liquefied natural gas storage tank 26, a back-pressure turbine 7, a mixer 8, a condensate distributor 9, a flue gas cooler 28, a pressure reducing valve 10, a generator 29, and a magnetic coupler 30.

[0150] The absorption tower 1 includes: a first inlet 101 located at the bottom of the absorption tower for flue gas to enter; a second inlet 102 located at the top of the absorption tower for lean absorbent solution to enter; a first outlet 103 located at the top of the absorption tower for flue gas to exit; and a second outlet 104 located at the bottom of the absorption tower for rich absorbent solution to exit.

[0151] The rich liquid pump 2 includes: a rich liquid pump inlet 201, which is connected to the second outlet 104 of the absorption tower; and a rich liquid pump outlet 202.

[0152] The rich liquid diverter 3 includes: a rich liquid diverter inlet 301, connected to the rich liquid pump outlet 202, a first outlet 302 of the rich liquid diverter; and a second outlet 303 of the rich liquid diverter.

[0153] The lean-rich liquid heat exchanger 4 includes: a first inlet 401 connected to the second outlet 303 of the rich liquid distributor; a first outlet 404 of the lean-rich liquid heat exchanger; a second inlet 402 connected to the outlet 1302 of the lean liquid pump; a third inlet 403 connected to the outlet 1202 of the flash vapor compressor; a second outlet 405 for lean liquid to flow out; and a third outlet 406 for flash-evaporated lean liquid vapor to flow out.

[0154] The regeneration tower 5 includes: a first inlet 501, connected to the first outlet 404 of the lean and rich liquid heat exchanger; a second inlet 502, connected to the first outlet 1703 of the steam heat exchanger; a third inlet 503, connected to the third outlet 406 of the lean and rich liquid heat exchanger; a fourth inlet 504, located at the bottom of the regeneration tower 5, connected to the fourth outlet 1810 of the multi-stream heat exchanger; a fifth inlet 505, connected to the first outlet 603 of the reboiler; a first outlet 506, connected to the junction of the pressure reducing valve inlet 1001 and the first inlet 601 of the reboiler; and a second outlet 507.

[0155] The reboiler 6 includes: a first reboiler inlet 601 connected to a first outlet 506 of the regeneration tower; a second reboiler inlet 602 connected to a mixer outlet 803; a first reboiler outlet 603 for stripping steam to flow out; and a second reboiler outlet 604.

[0156] The back-pressure steam turbine 7 includes: a back-pressure steam turbine inlet 701, into which low-pressure extracted steam from the power plant enters; and a back-pressure steam turbine outlet 702.

[0157] The mixer 8 includes: a first mixer inlet 801 connected to a back-pressure turbine outlet 702; a second mixer inlet 802 connected to a second outlet 903 of a condensate distributor; and a mixer outlet 803.

[0158] The condensate diverter 9 includes: a condensate diverter inlet 901, connected to the second outlet 604 of the reboiler; a condensate diverter first outlet 902, for returning condensate to the steam-water circulation system; and a condensate diverter second outlet 903.

[0159] The pressure reducing valve 10 includes: a pressure reducing valve inlet 1001, which is connected to the first outlet 506 of the regeneration tower; and a pressure reducing valve outlet 1002.

[0160] The flash tank 11 includes: a flash tank inlet 1101 connected to a pressure reducing valve outlet 1002; a flash tank first outlet 1102; and a flash tank second outlet 1103.

[0161] The flash compressor 12 includes: a flash compressor inlet 1201 connected to a first outlet 1102 of the flash tank; and a flash compressor outlet 1202.

[0162] The lean liquid pump 13 includes: a lean liquid pump inlet 1301, connected to the second outlet 1103 of the flash tank; and a lean liquid pump outlet 1302.

[0163] The lean liquid cooler 14 includes: a first inlet 1401 for the lean liquid cooler, connected to the second outlet 405 of the lean-rich liquid heat exchanger; a second inlet 1402 for the lean liquid cooler to receive cooling water; a first outlet 1403 for the lean liquid cooler; and a second outlet 1404 for the lean liquid cooler to receive cooling water.

[0164] The lean liquor mixer 15 includes: a first inlet 1501 for supplemental absorbent to flow in; a second inlet 1502 for supplemental water to flow in; a third inlet 1503 connected to a first outlet 1403 of the lean liquor cooler; and a lean liquor mixer outlet 1504.

[0165] The lean liquid pressure reducing valve 16 includes: a lean liquid pressure reducing valve inlet 1601, connected to a lean liquid mixer outlet 1504; and a lean liquid pressure reducing valve outlet 1602.

[0166] The regenerated gas heat exchanger 17 includes: a first inlet 1701 of the regenerated gas heat exchanger connected to a first outlet 302 of the rich liquid distributor; a second inlet 1702 of the regenerated gas heat exchanger connected to a second outlet 507 of the regeneration tower; a first outlet 1703 of the regenerated gas heat exchanger; and a second outlet 1704 of the regenerated gas heat exchanger.

[0167] The multi-flow heat exchanger 18 includes: a first inlet 1801, connected to the second outlet 1704 of the regeneration gas heat exchanger; a second inlet 1802, for cooling water to flow into; a third inlet 1803, connected to the outlet 2002 of the first-stage compressor; a fourth inlet 1804, connected to the second outlet 1903 of the two-phase separator; and a fifth inlet 1805, connected to the outlet of the carbon dioxide booster pump. 2502; the sixth inlet of the multi-flow heat exchanger 1806, connected to the outlet of the second-stage compressor 2202; the first outlet of the multi-flow heat exchanger 1807; the second outlet of the multi-flow heat exchanger 1808, for cooling water to flow out; the third outlet of the multi-flow heat exchanger 1809; the fourth outlet of the multi-flow heat exchanger 1810; the fifth outlet of the multi-flow heat exchanger 1811, for liquid carbon dioxide to flow out, connected to the transport pipeline; and the sixth outlet of the multi-flow heat exchanger 1812.

[0168] The two-phase separator 19 includes: a two-phase separator inlet 1901 connected to a first outlet 1807 of a multi-stream heat exchanger; a first outlet 1902 of the two-phase separator; and a second outlet 1903 of the two-phase separator.

[0169] The first-stage compressor 20 includes: a first-stage compressor inlet 2001 connected to a first outlet 1902 of a two-phase separator; and a first-stage compressor outlet 2002.

[0170] The first-stage gas-liquid separator 21 includes: a first-stage gas-liquid separator inlet 2101, connected to the third outlet 1809 of the multi-stream heat exchanger; a first-stage gas-liquid separator outlet 2102; and a second-stage gas-liquid separator outlet 2103, for condensate to flow out.

[0171] The second-stage compressor 22 includes: a second-stage compressor inlet 2201 connected to the first outlet 2102 of the first-stage gas-liquid separator; and a second-stage compressor outlet 2202.

[0172] The second-stage gas-liquid separator 23 includes: a second-stage gas-liquid separator inlet 2301, connected to the sixth outlet 1812 of the multi-flow heat exchanger; a second-stage gas-liquid separator first outlet 2302; and a second-stage gas-liquid separator second outlet 2303, for condensate to flow out.

[0173] The carbon dioxide condenser 24 includes: a first inlet 2401 for the carbon dioxide condenser, connected to the first outlet 2302 of the second-stage gas-liquid separator; a second inlet 2402 for the carbon dioxide condenser, connected to the outlet 2702 of the liquefied natural gas booster pump; a first outlet 2403 for the carbon dioxide condenser; and a second outlet 2404 for the carbon dioxide condenser, for the discharge of natural gas.

[0174] The carbon dioxide booster pump 25 includes: a carbon dioxide booster pump inlet 2501, connected to the first outlet 2403 of the carbon dioxide condenser; and a carbon dioxide booster pump outlet 2502.

[0175] The liquefied natural gas storage tank 26 includes: liquefied natural gas storage tank outlet 2601.

[0176] The liquefied natural gas booster pump 27 includes: a liquefied natural gas booster pump inlet 2701, connected to the liquefied natural gas storage tank outlet 2601; and a liquefied natural gas booster pump outlet 2702.

[0177] The flue gas cooler 28 includes: a first inlet 2801 for flue gas to flow in; a second inlet 2802 for cooling water to flow in; a first outlet 2803 connected to the first inlet 101 of the absorption tower 1; and a second outlet 2804 for cooling water to flow out. High-temperature flue gas enters the flue gas cooler 28 through the first inlet 2801 and is cooled by the cooling water entering the flue gas cooler 28 through the second inlet 2802. After the temperature rises, the cooling water is discharged from the second outlet 2804. The flue gas temperature drops to 40°C and then enters the absorption tower 1 through the first outlet 2803 and the first inlet 101 of the absorption tower.

[0178] High-temperature flue gas emitted from a stationary emission source (in one embodiment of this invention, the temperature can reach 100~120°C) enters the flue gas cooler 28 from the first inlet 2801. Since the carbon dioxide absorption reaction is exothermic, the low temperature condition can promote the forward absorption reaction. Therefore, the flue gas is cooled by cooling water entering the flue gas cooler 28 through the second inlet 2802 (in one embodiment of this invention, the cooling water reduces the flue gas temperature to about 40°C). The cooling water is discharged from the second outlet 2804 of the flue gas cooler, and the flue gas flows out through the first outlet 2803 of the flue gas cooler and enters the bottom of the absorption tower 1 from the first inlet 101 of the absorption tower.

[0179] The lean absorbent solution is an organic amine solution, which enters the top of the absorption tower 1 from the second inlet 102 of the absorption tower. It comes into countercurrent contact with the flue gas and undergoes an absorption reaction. Carbon dioxide and amine react to form carbamate. The purified flue gas, after the removal of carbon dioxide, is discharged from the first outlet 103 of the absorption tower, and the rich solution, which has absorbed carbon dioxide, is discharged from the second outlet 104 of the absorption tower.

[0180] The rich liquid enters the rich liquid pump 2 through the rich liquid pump inlet 201, and after being pressurized, it is discharged from the rich liquid pump outlet 202. It then enters the rich liquid distributor 3 through the rich liquid distributor inlet 301 and is divided into two streams. One stream of rich liquid is discharged from the first outlet 302 of the rich liquid distributor and enters the regeneration gas heat exchanger 17 through the first inlet 1701 of the regeneration gas heat exchanger. It exchanges heat with the high-temperature regeneration gas at the top outlet of the regeneration tower (in one embodiment of this utility model, the temperature is about 100~110℃) to recover the waste heat of the regeneration gas. After the temperature rises, the rich liquid enters the top of the regeneration tower 5 through the second inlet 502 of the regeneration tower. The remaining rich liquid enters the lean-rich liquid heat exchanger 4 from the first inlet 401 of the lean-rich liquid heat exchanger and is heated by the lean liquid. After the temperature rises, it flows out from the first outlet 404 of the lean-rich liquid heat exchanger and enters the top of the regeneration tower 5 through the first inlet 501 of the regeneration tower. Under the action of gravity, it flows from top to bottom and enters the reboiler 6 through the first outlet 506 of the regeneration tower and the first inlet 601 of the reboiler. It is heated by low-pressure steam extraction to generate stripping steam to achieve carbon dioxide desorption.

[0181] The low-pressure extraction steam in the power plant has a high pressure and temperature. If it is directly used to heat the reboiler 6, the absorbent will be severely degraded. Therefore, effectively recovering the pressure energy and heat energy of the low-pressure extraction steam can not only improve energy utilization efficiency, but also avoid damage to the system.

[0182] As attached Figure 3As shown, the low-pressure extraction steam from the power plant enters the back-pressure turbine 7 through the back-pressure turbine inlet 701, driving the impeller to expand and recover pressure energy. This energy also drives the flash compressor 12 via the common shaft and is connected to the generator 29 through the magnetic coupler 30 to generate electricity. After the pressure decreases, the low-pressure extraction steam exits from the back-pressure turbine outlet 702, passes through the first mixer inlet 801, and enters the mixer 8. It mixes with some condensate water that exits from the second outlet 903 of the condensate diverter and enters through the second mixer inlet 802 to recover superheated extraction steam. After the temperature decreases, the low-pressure extraction steam exits through the mixer outlet 803 and enters the reboiler 6 through the second reboiler inlet 602 for heating. After releasing heat, the low-pressure extraction steam becomes condensate water, exits from the second reboiler outlet 604, and enters the condensate diverter 9 through the condensate diverter inlet 901, splitting into two streams. One stream flows out from the second outlet 903 of the condensate diverter to recover superheated extraction steam, and the other stream returns to the steam unit's steam-water cycle through the first outlet 902 of the condensate diverter.

[0183] In reboiler 6, the rich liquor is heated to generate stripping steam that flows upward, transferring heat to the rich liquor and causing a desorption reaction. After desorption, carbon dioxide carries a large amount of water vapor and is discharged from the second outlet 507 of the regeneration tower.

[0184] High-temperature lean liquor is discharged from the first outlet 506 of the regeneration tower, enters the pressure reducing valve 10 through the pressure reducing valve inlet 1001, and the outlet pressure is within the range of the regeneration tower pressure and the absorption tower pressure. After the pressure is reduced, the lean liquor is discharged from the pressure reducing valve outlet 1002 and enters the flash tank 11 through the flash tank inlet 1101 for flash evaporation. The flash steam is discharged from the first outlet 1102 of the flash tank, enters the flash steam compressor 12 through the flash steam compressor inlet 1201 to be pressurized, and compressed to the regeneration tower pressure. After the pressure is increased, it is discharged from the flash steam compressor outlet 1202 and enters the lean-rich liquor heat exchanger 4 through the third inlet 403 to heat the rich liquor and recover heat (heating the rich liquor entering from the first inlet 401 of the lean-rich liquor heat exchanger to reduce the temperature to the reboiler temperature). The flash steam after the temperature is reduced is discharged from the third outlet 406 of the lean-rich liquor heat exchanger and enters the bottom of the regeneration tower 5 through the third inlet 503 of the regeneration tower. The remaining lean liquid is discharged from the second outlet 1103 of the flash tank, enters the lean liquid pump 13 through the lean liquid pump inlet 1301, and flows out from the lean liquid pump outlet 1302 after the pressure increases. It then enters the lean-rich liquid heat exchanger 4 through the second inlet 402 of the lean-rich liquid heat exchanger to heat the rich liquid and recover heat. After heat exchange, the lean liquid flows out from the second outlet 405 of the lean-rich liquid heat exchanger and enters the lean liquid cooler 14 through the first inlet 1401 of the lean liquid cooler. It exchanges heat with the cooling water that enters the lean liquid cooler 14 through the second inlet 1402 of the lean liquid cooler. After the cooling water is heated, it flows out through the second outlet 1404 of the lean liquid cooler. The lean liquid is further cooled (in one embodiment of this utility model, the temperature is reduced to 40°C) and then flows out from the first outlet 1403 of the lean liquid cooler. It enters the lean liquid mixer 15 through the third inlet 1503 of the lean liquid mixer and mixes with the makeup water that enters the lean liquid mixer 15 through the second inlet 1502 of the lean liquid mixer and the supplementary absorbent (in one embodiment of this utility model, an organic amine) that enters the lean liquid mixer 15 through the first inlet 1501 of the lean liquid mixer to maintain a constant concentration. The lean liquor flows out from the outlet 1504 of the lean liquor mixer, enters the lean liquor pressure reducing valve 16 through the inlet 1601 of the lean liquor pressure reducing valve, reduces the pressure, and then is discharged from the outlet 1602 of the lean liquor pressure reducing valve. It then returns to the absorption tower 1 from the second inlet 102 of the absorption tower, completing the absorption-desorption cycle.

[0185] The regeneration gas (a mixture of carbon dioxide and water vapor) at the top of the regeneration tower is discharged from the second outlet 507 of the regeneration tower and enters the regeneration gas heat exchanger 17 via the second regeneration gas inlet 1702 to heat the rich liquid in the regeneration gas heat exchanger 17 (the rich liquid enters the regeneration gas heat exchanger 17 via the first outlet 302 of the rich liquid distributor and the first inlet 1701 of the regeneration gas heat exchanger). After recovering some heat, the regeneration gas flows out from the second outlet 1704 of the regeneration gas heat exchanger and enters the multi-stream heat exchanger 18 via the first inlet 1801 of the multi-stream heat exchanger to recover the remaining heat. Waste heat; after the temperature decreases, the regenerated gas flows out from the first outlet 1807 of the multi-flow heat exchanger, enters the two-phase splitter 19 through the inlet 1901 of the two-phase splitter, and the water vapor condenses into condensate, which is discharged from the second outlet 1903 of the two-phase splitter and enters the multi-flow heat exchanger 18 through the fourth inlet 1804 of the multi-flow heat exchanger to recover heat; after the temperature increases, the condensate is discharged from the fourth outlet 1810 of the multi-flow heat exchanger and enters the regeneration tower 5 through the fourth inlet 504 of the regeneration tower to maintain the system water balance.

[0186] After the condensate is removed, carbon dioxide is discharged from the first outlet 1902 of the two-phase separator and enters the first-stage compressor 20 through the inlet 2001 of the first-stage compressor for pressurization, with a compression ratio of approximately 3. After the carbon dioxide pressure increases, it flows out from the outlet 2002 of the first-stage compressor and enters the multi-flow heat exchanger 18 through the third inlet 1803 to recover the heat of compression. After the temperature decreases, the carbon dioxide is discharged from the third outlet 1809 of the multi-flow heat exchanger and enters the first-stage gas-liquid separator 21 through the first inlet 2101 to remove the condensate. The condensate then exits from the second outlet 21 of the first-stage gas-liquid separator. 03. Carbon dioxide is discharged from the first outlet 2102 of the first-stage gas-liquid separator and enters the second-stage compressor 22 through the inlet 2201 of the second-stage compressor. It continues to be pressurized to the liquefaction pressure. After the pressure rises to the liquefaction pressure, it is discharged from the outlet 2202 of the second-stage compressor and enters the multi-flow heat exchanger 18 through the sixth inlet 1806 of the multi-flow heat exchanger to recover the second-stage compression heat. After the temperature drops, carbon dioxide is discharged from the sixth outlet 1812 of the multi-flow heat exchanger and enters the second-stage gas-liquid separator 23 through the inlet 2301 of the second-stage gas-liquid separator. The remaining condensate is discharged from the second outlet 2303 of the second-stage gas-liquid separator.

[0187] After removing water vapor, high-purity carbon dioxide is discharged from the first outlet 2302 of the second-stage gas-liquid separator and enters the carbon dioxide condenser 24 through the first inlet 2401. Liquefied natural gas (LNG) is discharged from the LNG storage tank outlet 2601, enters the LNG booster pump 27 through the LNG booster pump inlet 2701, and after pressure increase, is discharged from the LNG booster pump outlet 2702. It then enters the carbon dioxide condenser 24 through the second inlet 2402, releasing cold energy and liquefying the carbon dioxide. After recovering the cold energy, the LNG becomes natural gas and is discharged from the second outlet 2404 of the carbon dioxide condenser, where it is burned as fuel to generate electricity.

[0188] The liquefied carbon dioxide is discharged from the first outlet 2403 of the carbon dioxide condenser and enters the carbon dioxide booster pump 25 through the inlet 2501 of the carbon dioxide booster pump, which increases the pressure to the transport pressure (approximately 150 bar in some embodiments of the present invention). After pressurization, the liquid carbon dioxide is discharged from the outlet 2502 of the carbon dioxide booster pump and enters the multi-flow heat exchanger 18 through the fifth inlet 1805 of the multi-flow heat exchanger to recover the remaining cold energy. After the temperature rises to the pipeline transport temperature (approximately 30°C in some embodiments of the present invention), the carbon dioxide is discharged from the fifth outlet 1811 of the multi-flow heat exchanger and enters the transport pipeline to be transported to the storage or utilization site.

[0189] This embodiment of the invention utilizes a rich liquid distributor and a regenerated gas heat exchanger to recover the waste heat of the regenerated gas at the top of the regeneration tower for heating the rich liquid, while simultaneously reducing the sensible and latent heat of absorbent regeneration. A pressure reducing valve and a flash compressor are used to recover the latent heat of the high-temperature lean liquid, and a back-pressure turbine and mixer are used to recover the pressure energy and superheat of the low-pressure extraction steam, reducing the extraction volume and driving the flash compressor and power generation. Furthermore, the cold energy of liquefied natural gas is used to liquefy carbon dioxide at intermediate pressure, reducing the number of compression stages and compression power consumption. A multi-stream heat exchanger is used to recover the heat of carbon dioxide compression for heating condensate, further reducing latent heat and cooling water usage. This achieves full recovery of waste heat and efficient utilization of liquefied natural gas cold energy in the chemical absorption carbon dioxide capture and compression system, improving the system's energy efficiency and economy.

[0190] This utility model embodiment can fully recover the superheat and pressure energy of the extracted steam, the waste heat of the top flow of the regeneration tower, the heat of carbon dioxide compression, and the cold energy of liquefied natural gas, realizing the cascade utilization of energy and combined heat and power, saving the number of equipment and the amount of public works used, and improving the energy utilization efficiency and thermal economy of the system.

[0191] The embodiments given above are preferred examples of implementing this utility model, and this utility model is not limited to the above embodiments. Any non-essential additions or substitutions made by those skilled in the art based on the technical features of the technical solution of this utility model shall fall within the protection scope of this utility model.

Claims

1. A carbon capture and compression system based on the comprehensive utilization of waste heat and LNG cold energy, characterized in that, include: The absorption tower (1) includes: The first inlet (101) of the absorption tower is located at the bottom of the absorption tower for the flue gas to enter; The second inlet (102) of the absorption tower is located at the top of the absorption tower to supply the lean absorbent solution. The first outlet (103) of the absorption tower is located at the top of the absorption tower for flue gas discharge; The second outlet (104) of the absorber tower is located at the bottom of the absorber tower for discharging the rich absorbent solution; the rich solution distributor (3) includes: The inlet of the rich liquid distributor (301) is connected to the second outlet of the absorption tower (104). First outlet of the rich liquid distributor (302); Second outlet of the rich liquid distributor (303); The rich and poor liquid heat exchanger (4) includes: The first inlet (401) of the lean and rich liquid heat exchanger is connected to the second outlet (303) of the rich liquid distributor. First outlet of the rich and poor liquid heat exchanger (404); Regeneration tower (5), comprising: The first inlet of the regeneration tower (501) is connected to the first outlet of the lean and rich liquid heat exchanger (404). The second inlet (502) of the regeneration tower is connected to the first outlet (1703) of the steam heat exchanger. The fifth inlet of the regeneration tower (505) is connected to the first outlet of the reboiler (603). The first outlet (506) of the regeneration tower is located at the junction of the pressure reducing valve inlet (1001) and the first inlet (601) of the reboiler; Second outlet of the regeneration tower (507); The reboiler (6) includes: The first inlet of the reboiler (601) is connected to the first outlet of the regeneration tower (506). The first outlet (603) of the reboiler is for stripping steam to flow out.

2. The carbon capture and compression system based on the comprehensive utilization of waste heat and LNG cold energy according to claim 1, characterized in that, It also includes a flue gas cooler (28), which includes: The first inlet (2801) of the flue gas cooler allows flue gas to flow in. The second inlet (2802) of the flue gas cooler allows cooling water to flow in. The first outlet (2803) of the flue gas cooler is connected to the first inlet (101) of the absorption tower; The second outlet (2804) of the flue gas cooler is for cooling water to flow out.

3. A carbon capture and compression system based on the comprehensive utilization of waste heat and LNG cold energy according to claim 2, characterized in that, After being cooled by the flue gas cooler (28), the flue gas enters the absorption tower (1) through the first inlet (101) and comes into countercurrent contact with the absorbent lean liquid that enters from the second inlet (102) of the absorption tower. A chemical reaction occurs to remove carbon dioxide, and the purified flue gas is discharged from the first outlet (103) of the absorption tower. The absorbent rich liquid that has absorbed carbon dioxide flows out from the second outlet (104) of the absorption tower. The rich liquid enters the rich liquid distributor (3) through the rich liquid distributor inlet (301), and part of the rich liquid enters the rich liquid heat exchanger (4) through the rich liquid distributor second outlet (303) and the rich liquid heat exchanger first inlet (401). After absorbing heat and heating up, it flows out from the rich liquid heat exchanger first outlet (404). The rich liquid flowing out from the first outlet (404) of the rich and lean liquid heat exchanger enters the top of the regeneration tower (5) through the first inlet (501) of the regeneration tower. Under the action of gravity, it flows from top to bottom and enters the reboiler (6) through the first outlet (506) of the regeneration tower and the first inlet (601) of the reboiler. It is heated by low-pressure steam extraction to generate stripping steam. The stripping steam enters the regeneration tower (5) through the first outlet (603) of the reboiler and the fifth inlet (505) of the regeneration tower and comes into countercurrent contact with the rich liquid to cause a desorption reaction. The desorbed carbon dioxide carries a large amount of water vapor and is discharged from the regeneration tower (5) through the second outlet (507).

4. A carbon capture and compression system based on the comprehensive utilization of waste heat and LNG cold energy according to claim 3, characterized in that, It also includes a rich liquid pump (2), which includes: a rich liquid pump inlet (201) connected to the second outlet (104) of the absorption tower, and a rich liquid pump outlet (202) connected to the inlet (301) of the rich liquid distributor; the rich liquid enters the rich liquid pump (2) from the rich liquid pump inlet (201), and flows out from the rich liquid pump outlet (202) after the pressure is increased.

5. A carbon capture and compression system based on the comprehensive utilization of waste heat and LNG cold energy according to claim 1, characterized in that, The lean and rich liquid heat exchanger (4) also includes: Second inlet (402) of the rich and poor liquid heat exchanger; Third inlet (403) of the rich and poor liquid heat exchanger; The second outlet (405) of the lean and rich liquid heat exchanger is for the lean liquid to flow out. The third outlet (406) of the lean liquid heat exchanger is used to supply the flash-evaporated lean liquid vapor. The regeneration tower (5) also includes: The third inlet (503) of the regeneration tower is connected to the third outlet (406) of the lean and rich liquid heat exchanger. The system also includes: Pressure reducing valve (10), comprising: The pressure reducing valve inlet (1001) is connected to the first outlet (506) of the regeneration tower. Pressure reducing valve outlet (1002); Flash evaporator (11), comprising: The flash tank inlet (1101) is connected to the pressure reducing valve outlet (1002). First outlet of flash tank (1102); Second outlet of flash tank (1103); Flash vapor compressor (12), comprising: The flash vapor compressor inlet (1201) is connected to the first outlet (1102) of the flash tank. The flash vapor compressor outlet (1202) is connected to the third inlet (403) of the lean and rich liquid heat exchanger. The lean liquid pump (13) includes: The lean liquid pump inlet (1301) is connected to the second outlet (1103) of the flash tank. The outlet of the lean liquid pump (1302) is connected to the second inlet (402) of the lean and rich liquid heat exchanger. The lean liquid cooler (14) includes: The first inlet (1401) of the lean liquid cooler is connected to the second outlet (405) of the lean and rich liquid heat exchanger. The second inlet (1402) of the lean liquid cooler allows cooling water to flow in; First outlet of lean liquid cooler (1403); The second outlet (1404) of the lean liquid cooler is for cooling water to flow out; The lean liquid mixer (15) includes: The first inlet (1501) of the lean liquid mixer is for the inflow of supplemental absorbent; The second inlet (1502) of the lean liquid mixer is for the inflow of makeup water; The third inlet (1503) of the lean liquor mixer is connected to the first outlet (1403) of the lean liquor cooler. Lean liquor mixer outlet (1504); The lean liquid pressure reducing valve (16) includes: The lean liquid pressure reducing valve inlet (1601) is connected to the lean liquid mixer outlet (1504). Lean liquid pressure reducing valve outlet (1602).

6. A carbon capture and compression system based on the comprehensive utilization of waste heat and LNG cold energy according to claim 5, characterized in that, After the absorbent is regenerated, it enters the pressure reducing valve (10) through the first outlet (506) of the regeneration tower and the inlet (1001) of the pressure reducing valve. After the pressure is reduced, the lean liquid enters the flash tank (11) through the outlet (1002) of the pressure reducing valve and the inlet (1101) of the flash tank for flash evaporation. The lean liquid vapor enters the flash compressor (12) through the first outlet (1102) of the flash tank and the inlet (1201) of the flash compressor. After being compressed to the regeneration tower pressure, it enters the lean-rich liquid heat exchanger (4) through the outlet (1202) of the flash compressor and the third inlet (403) of the lean-rich liquid heat exchanger to heat the rich liquid entering from the first inlet (401) of the lean-rich liquid heat exchanger, so that the temperature is reduced to the reboiler temperature. The cooled flash vapor enters the regeneration tower (5) through the third outlet (406) of the lean-rich liquid heat exchanger and the third inlet (503) of the regeneration tower for heating. The lean liquor flows out from the second outlet (1103) of the flash tank, enters the lean liquor pump (13) through the lean liquor pump inlet (1301), and after being pressurized, enters the lean-rich liquor heat exchanger (4) through the lean liquor pump outlet (1302) and the second inlet (402) of the lean-rich liquor heat exchanger to heat the rich liquor and recover heat. After the temperature decreases, the lean liquor enters the lean liquor cooler (14) through the second outlet (405) of the lean-rich liquor heat exchanger and the first inlet (1401) of the lean liquor cooler, and exchanges heat with the cooling water that enters the lean liquor cooler (14) through the second inlet (1402). After the cooling water is heated, it flows out through the second outlet (1404) of the lean liquor cooler. After the temperature decreases, The lean liquid enters the lean liquid mixer (15) through the first outlet (1403) of the lean liquid cooler and the third inlet (1503) of the lean liquid mixer. It mixes with the supplementary absorbent that enters the lean liquid mixer (15) through the first inlet (1501) of the lean liquid mixer and the supplementary water that enters the lean liquid mixer (15) through the second inlet (1502) of the lean liquid mixer to maintain a constant concentration. The lean liquid enters the lean liquid pressure reducing valve (16) through the outlet (1504) of the lean liquid mixer and the inlet (1601) of the lean liquid pressure reducing valve. After the pressure is reduced, it enters the absorption tower (1) through the outlet (1602) of the lean liquid pressure reducing valve and the second inlet (102) of the absorption tower to complete the process cycle.

7. A carbon capture and compression system based on the comprehensive utilization of waste heat and LNG cold energy according to any one of claims 1-6, characterized in that, The regeneration tower (5) also includes: The fourth inlet (504) of the regeneration tower is located at the bottom of the regeneration tower (5); The system also includes: The regenerated gas heat exchanger (17) includes: The first inlet (1701) of the regenerated gas heat exchanger is connected to the first outlet (302) of the rich liquid distributor. The second inlet (1702) of the regenerated gas heat exchanger is connected to the second outlet (507) of the regeneration tower. First outlet of regenerated gas heat exchanger (1703); Second outlet of regenerated gas heat exchanger (1704); Multi-flow heat exchanger (18), comprising: The first inlet (1801) of the multi-flow heat exchanger is connected to the second outlet (1704) of the regeneration gas heat exchanger. The second inlet (1802) of the multi-flow heat exchanger is for the inflow of cooling water; Third inlet (1803) of multi-flow heat exchanger; Fourth inlet (1804) of multi-flow heat exchanger; Fifth inlet (1805) of multi-flow heat exchanger; Sixth inlet (1806) of multi-flow heat exchanger; First outlet of multi-flow heat exchanger (1807); The second outlet (1808) of the multi-flow heat exchanger is for cooling water to flow out. Third outlet of multi-flow heat exchanger (1809); The fourth outlet (1810) of the multi-flow heat exchanger is connected to the fourth inlet (504) of the regeneration tower. The fifth outlet (1811) of the multi-flow heat exchanger is for liquid carbon dioxide to flow out and is connected to the transport pipeline; Sixth outlet of multi-flow heat exchanger (1812); Two-phase separator (19), comprising: The inlet of the two-phase separator (1901) is connected to the first outlet of the multi-stream heat exchanger (1807). First outlet of the two-phase separator (1902); The second outlet of the two-phase separator (1903) is connected to the fourth inlet of the multi-stream heat exchanger (1804). The first-stage compressor (20) includes: The inlet of the first-stage compressor (2001) is connected to the first outlet of the two-phase separator (1902). The first stage compressor outlet (2002) is connected to the third inlet (1803) of the multi-flow heat exchanger. The first-stage gas-liquid separator (21) includes: The inlet of the first-stage gas-liquid separator (2101) is connected to the third outlet of the multi-stream heat exchanger (1809). First outlet of the first-stage gas-liquid separator (2102); The second outlet (2103) of the first-stage gas-liquid separator is for condensate to flow out. The second-stage compressor (22) includes: The inlet of the second-stage compressor (2201) is connected to the first outlet of the first-stage gas-liquid separator (2102). The outlet of the second-stage compressor (2202) is connected to the sixth inlet (1806) of the multi-flow heat exchanger. The second-stage gas-liquid separator (23) includes: The inlet of the second-stage gas-liquid separator (2301) is connected to the sixth outlet (1812) of the multi-stream heat exchanger. The first outlet of the second-stage gas-liquid separator (2302); The second outlet (2303) of the second-stage gas-liquid separator is for condensate to flow out. The carbon dioxide condenser (24) includes: The first inlet (2401) of the carbon dioxide condenser is connected to the first outlet (2302) of the second-stage gas-liquid separator. The second inlet (2402) of the carbon dioxide condenser is for liquefied natural gas to enter; First outlet of carbon dioxide condenser (2403); The second outlet (2404) of the carbon dioxide condenser is for natural gas discharge; The carbon dioxide booster pump (25) includes: The carbon dioxide booster pump inlet (2501) is connected to the first outlet (2403) of the carbon dioxide condenser. The outlet of the carbon dioxide booster pump (2502) is connected to the fifth inlet (1805) of the multi-flow heat exchanger. Among them, the regenerated gas, which is a mixture of carbon dioxide and water vapor, enters the regenerated gas heat exchanger (17) through the second outlet (507) of the regenerated tower and the second inlet (1702) of the regenerated gas heat exchanger, and heats the rich liquid that enters the regenerated gas heat exchanger (17) through the first outlet (302) of the rich liquid distributor and the first inlet (1701) of the regenerated gas heat exchanger. After the rich liquid is heated, it enters the regenerated tower (5) through the second inlet (502) of the regenerated tower. After recovering some heat, the regenerated gas enters the multi-stream heat exchanger (18) through the second outlet (1704) of the regenerated gas heat exchanger and the first inlet (1801) of the multi-stream heat exchanger to recover the remaining heat. After the temperature drops, the regenerated gas enters the two-phase separator (19) through the first outlet (1807) of the multi-stream heat exchanger and the inlet (1901) of the two-phase separator. The water vapor condenses into condensate, which enters the multi-stream heat exchanger (18) through the second outlet (1903) of the two-phase separator and the fourth inlet (1804) of the multi-stream heat exchanger to be heated. After the temperature rises, it enters the bottom of the regeneration tower (5) through the fourth outlet (1810) of the multi-stream heat exchanger and the fourth inlet (504) of the regeneration tower. Carbon dioxide enters the first-stage compressor (20) via the first outlet (1902) of the two-phase separator and the inlet (2001) of the first-stage compressor for pressurization. After being heated and pressurized, the carbon dioxide enters the multi-stream heat exchanger (18) via the first-stage compressor outlet (2002) and the third inlet (1803) of the multi-stream heat exchanger to recover the heat of compression. After the temperature decreases, the carbon dioxide enters the first-stage gas-liquid separator (21) via the third outlet (1809) of the multi-stream heat exchanger and the inlet (2101) of the first-stage gas-liquid separator. The condensate is discharged from the second outlet (2103) of the first-stage gas-liquid separator. The carbon dioxide enters the second-stage compressor (22) through the first outlet (2102) of the first-stage gas-liquid separator and the inlet (2201) of the second-stage compressor, and continues to be pressurized to the liquefaction pressure. After pressurization, the carbon dioxide enters the multi-flow heat exchanger (18) through the outlet (2202) of the second-stage compressor and the sixth inlet (1806) of the multi-flow heat exchanger to recover the heat of compression. After the temperature decreases, the carbon dioxide enters the second-stage gas-liquid separator (23) through the sixth outlet (1812) of the multi-flow heat exchanger and the inlet (2301) of the second-stage gas-liquid separator. The remaining condensate is discharged through the second outlet (2303) of the second-stage gas-liquid separator. After removing water vapor, carbon dioxide enters the carbon dioxide condenser (24) through the first outlet (2302) of the second-stage gas-liquid separator and the first inlet (2401) of the carbon dioxide condenser. Liquefied natural gas enters the carbon dioxide condenser (24) and exchanges heat with carbon dioxide to liquefy it under intermediate pressure. After liquefaction, carbon dioxide enters the carbon dioxide booster pump (25) through the first outlet (2403) of the carbon dioxide condenser and the inlet (2501) of the carbon dioxide booster pump, raising the pressure to the pipeline transportation pressure. After pressurization, liquid carbon dioxide enters the multi-stream heat exchanger (18) through the outlet (2502) of the carbon dioxide booster pump and the fifth inlet (1805) of the multi-stream heat exchanger to recover the remaining cold energy. After being heated to the pipeline transportation temperature, it enters the carbon dioxide transportation pipeline through the fifth outlet (1811) of the multi-stream heat exchanger. After recovering the cold energy, the liquefied natural gas becomes natural gas and enters the subsequent utilization stage through the second outlet (2404) of the carbon dioxide condenser.

8. A carbon capture and compression system based on the comprehensive utilization of waste heat and LNG cold energy according to claim 7, characterized in that, It also includes liquefied natural gas storage tanks (26), including: liquefied natural gas storage tank outlets (2601); It also includes a liquefied natural gas booster pump (27), which includes: The inlet of the liquefied natural gas booster pump (2701) is connected to the outlet of the liquefied natural gas storage tank (2601). The outlet of the liquefied natural gas booster pump (2702) is connected to the second inlet (2402) of the carbon dioxide condenser; Liquefied natural gas enters the liquefied natural gas booster pump (27) through the outlet (2601) of the liquefied natural gas storage tank and the inlet (2701) of the liquefied natural gas booster pump; after the pressure increases, the liquefied natural gas enters the carbon dioxide condenser (24) through the outlet (2702) of the liquefied natural gas booster pump and the second inlet (2402) of the carbon dioxide condenser and exchanges heat with carbon dioxide to liquefy it under intermediate pressure.

9. A carbon capture and compression system based on the comprehensive utilization of waste heat and LNG cold energy according to claim 5, characterized in that, The reboiler (6) also includes: Second inlet of reboiler (602); Second outlet of reboiler (604); The system also includes: The mixer (8) includes: The mixer's first inlet (801) is for low-pressure extraction steam to enter; Mixer second inlet (802); The mixer outlet (803) is connected to the second inlet (602) of the reboiler. Condensation diverter (9), comprising: The condensate diverter inlet (901) is connected to the second outlet of the reboiler (604). The first outlet (902) of the condensate diverter supplies condensate water back to the steam-water circulation system; The second outlet (903) of the condensate distributor is connected to the second inlet (802) of the mixer. Low-pressure extraction steam enters the mixer (8) through the first inlet (801) of the mixer and mixes with some of the condensate that enters the mixer (8) through the second outlet (903) of the condensate diverter and the second inlet (802) of the mixer to recover the superheat of the extraction steam. After the temperature drops, the low-pressure extraction steam enters the reboiler (6) through the outlet (803) of the mixer and the second inlet (602) of the reboiler for heating. After releasing heat, the extraction steam becomes condensate and enters the condensate diverter (9) through the second outlet (604) of the reboiler and the inlet (901) of the condensate diverter. Some of the condensate returns to the steam-water circulation through the first outlet (902) of the condensate diverter.

10. A carbon capture and compression system based on the comprehensive utilization of waste heat and LNG cold energy according to claim 9, characterized in that, It also includes a generator (29), a magnetic coupler (30), and a back-pressure turbine (7), the back-pressure turbine (7) comprising; Back pressure turbine inlet (701), low-pressure extracted steam from the power plant enters; Back pressure turbine outlet (702) connects to the first inlet of mixer (801); The low-pressure extracted steam from the power plant enters the back pressure turbine (7) through the back pressure turbine inlet (701), drives the impeller to do work and recover pressure energy, and drives the flash compressor (12) through the common shaft; the remaining mechanical energy is converted into electrical energy by connecting the generator (29) through the magnetic coupler (30); after the pressure is reduced, the low-pressure extracted steam enters the mixer (8) through the back pressure turbine outlet (702) and the first inlet of the mixer (801).

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