Amine method carbon capture and carbon dioxide compression liquefaction coupling system

Abstract

The utility model provides an amine method carbon capture and carbon dioxide compression liquefaction coupling system, which not only can reduce the input heat of a desorption tower of an amine method carbon capture system, but also can reduce the cooling capacity required by interstage cooling of a compressor. The system specifically comprises a three-stage compressor, a three-stage compressor interstage heat exchanger, a three-stage compressor exhaust cooler, a delivery pump, a steam-water separator, a desorption tower and a condenser. After carbon capture, carbon dioxide is pressurized and heated through a compressor, high-temperature and high-pressure carbon dioxide exhaust enters an interstage heat exchanger to heat a medium at an outlet in the bottom of a steam-water separator, and the carbon dioxide passes through an interstage exhaust cooler and is cooled to 40 DEG C for next-stage compression.

Description

Technical Field

[0001] The utility model relates to the field of waste heat utilization, and mainly relates to an amine-based carbon capture and carbon dioxide compression and liquefaction coupling system. Background Technique

[0002] In the existing amine-based carbon capture carbon dioxide compression and liquefaction system, the carbon dioxide gas after carbon capture needs to be pressurized by a compressor and then liquefied. The compressor adopts a multi-stage compressor (usually three-stage compression). While increasing the pressure, the temperature of the carbon dioxide gas also rises. The inter-stage exhaust temperature is about 140°C, and the carbon dioxide inter-stage exhaust temperature needs to be cooled to about 40°C and then enter the next stage of compression.

[0003] Patent CN201920164500.7 discloses a carbon dioxide compressor after-cooling system, including a carbon dioxide compressor, a cooler, a first-stage separator, a second-stage separator, a separation buffer distributor and a pre-cooler. The carbon dioxide inter-stage exhaust is cooled by cooling water, and the cooler adopts a detachable shell-and-tube cooler.

[0004] Patent CN202222620551.0 discloses a waste heat recovery system at the outlet of a carbon dioxide compressor, including a heat exchanger, a cooler, a lithium bromide unit, and a circulating water pump. The waste heat of the raw material gas at the outlet of the carbon dioxide raw material compressor is recovered by using a bromine refrigeration unit to produce cooling capacity, and the cooling capacity is used to reduce the temperature of the raw material gas.

[0005] In the prior art, the inter-stage exhaust of the compressor is cooled by cooling water, resulting in a large consumption of cooling water and low energy utilization rate.

[0006] A "Carbon Dioxide Compressor After-Cooling System" disclosed in Patent CN201920164500.7 mainly has the following problems: ① Cooling with cooling water results in a large consumption of cooling water; ② All heat is carried away by cooling water and cannot be recycled.

[0007] A "Waste Heat Recovery System at the Outlet of a Carbon Dioxide Compressor" disclosed in Patent CN202222620551.0 mainly has the following problems: ① The exhaust heat in the medium temperature section is cooled by cooling water and cannot be effectively utilized; ② The lithium bromide unit recovers carbon dioxide and the system is relatively complex. Utility Model Content

[0008] To solve the above problems existing in the prior art, the present utility model provides an amine-based carbon capture and carbon dioxide compression and liquefaction coupling system, which can not only reduce the input heat of the desorber in the amine-based carbon capture system, but also reduce the cooling capacity required for inter-stage cooling of the compressor. Specifically, it includes a three-stage compressor, a three-stage compressor inter-stage heat exchanger, a three-stage compressor exhaust cooler, a transfer pump, a steam-water separator, a desorber, and a condenser. After carbon capture, carbon dioxide is pressurized and heated by the compressor, and the high-temperature and high-pressure carbon dioxide exhaust enters the inter-stage heat exchanger to heat the medium at the bottom outlet of the steam-water separator. Then, the carbon dioxide passes through the inter-stage exhaust cooler and is cooled to 40 °C for the next-stage compression.

[0009] The technical solution of the present utility model is as follows: An amine-based carbon capture and carbon dioxide compression and liquefaction coupling system includes a carbon capture system and a carbon dioxide compression and liquefaction coupling system; the carbon capture system is connected to the carbon dioxide compression and liquefaction coupling system through a heat exchange pipeline.

[0010] The carbon capture system includes: along the flue gas direction, a desorber, a condenser, a steam-water separator, and a transfer pump are sequentially connected and arranged, and then are respectively connected to a first-stage compressor exhaust heat exchanger, a second-stage compressor exhaust heat exchanger, and a third-stage compressor exhaust heat exchanger; the flue gas is the high-temperature water vapor of the desorber, and the high-temperature water vapor enters the steam-water separator after being cooled by the condenser.

[0011] The carbon dioxide compression and liquefaction coupling system includes: along the flue gas direction, a first-stage compressor, a first-stage compressor exhaust heat exchanger, a first-stage compressor exhaust cooler, a second-stage compressor, a second-stage compressor exhaust heat exchanger, a second-stage compressor exhaust cooler, a third-stage compressor, a third-stage compressor exhaust heat exchanger, and a third-stage compressor exhaust cooler are sequentially connected and arranged.

[0012] Preferably, the first-stage compressor exhaust heat exchanger, the second-stage compressor exhaust heat exchanger, and the third-stage compressor exhaust heat exchanger are respectively provided with a first-stage heat exchange pipeline, a second-stage heat exchange pipeline, and a third-stage heat exchange pipeline.

[0013] The connection mode of the carbon capture system and the carbon dioxide compression and liquefaction coupling system through the heat exchange pipeline includes that, along the flue gas direction, the flue gas outlet of the transfer pump is respectively connected to the first-stage heat exchange pipeline of the first-stage compressor exhaust heat exchanger, the second-stage heat exchange pipeline of the second-stage compressor exhaust heat exchanger, and the third-stage heat exchange pipeline of the third-stage compressor exhaust heat exchanger, and then is connected to the desorber.

[0014] Preferably, the transfer pump returns a certain proportion of the remaining liquid separated by the steam-water separator to the front end of the desorber through the heat exchange pipeline.

[0015] Preferably, the remaining liquid enters the desorber and is mixed with the rich liquid to be heated to obtain a heated rich liquid; the heated rich liquid is desorbed to obtain high-temperature water vapor and lean liquid.

[0016] Preferably, the primary compressor, the secondary compressor, and the tertiary compressor are respectively provided with a primary compression pipeline, a secondary compression pipeline, and a tertiary compression pipeline;

[0017] The primary compressor exhaust cooler, the secondary compressor exhaust cooler, and the tertiary compressor exhaust cooler are respectively provided with a primary cooling pipeline, a secondary cooling pipeline, and a tertiary cooling pipeline.

[0018] Preferably, the carbon dioxide compression and liquefaction coupling system further includes: along the direction of the low-pressure gas, the gas compressed by the primary compressor sequentially passes through the primary heat exchange pipeline of the primary compressor exhaust heat exchanger and the primary cooling pipeline of the primary compressor exhaust cooler and enters the secondary compressor for compression, and then sequentially passes through the secondary heat exchange pipeline of the secondary compressor exhaust heat exchanger and the secondary cooling pipeline of the secondary compressor exhaust cooler and enters the tertiary compressor for compression, and finally passes through the tertiary heat exchange pipeline of the tertiary compressor exhaust heat exchanger and the tertiary cooling pipeline of the tertiary compressor exhaust cooler and is discharged;

[0019] The gas is low-pressure and low-temperature carbon dioxide gas; the discharged flue gas is high-pressure and low-temperature carbon dioxide gas.

[0020] Preferably, the steam-water separator separates the high-temperature water vapor into carbon dioxide gas and the remaining liquid-phase working medium. Preferably, the primary compressor exhaust heat exchanger, the secondary compressor exhaust heat exchanger, and the tertiary compressor exhaust heat exchanger are all inter-stage heat exchangers, and the inter-stage heat exchangers adopt shell-and-tube / plate heat exchange.

[0021] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0022] 1. By means of the inter-stage heat exchanger, the present utility model cools the exhaust gas of the compressor with the liquid-phase working medium at the bottom of the carbon capture steam-water separator, reducing the energy consumption for cooling the exhaust gas of the compressor and reducing the amount of cooling water used.

[0023] 2. The present utility model reduces the energy consumption of the carbon capture system. The heat of the carbon dioxide exhaust gas of the compressor is used to heat the liquid-phase working medium returned from the carbon capture steam-water separator to the desorption tower, and the heat of the carbon dioxide exhaust gas can replace part of the heat originally input externally.

[0024] 3. The temperature of the liquid-phase working medium at the bottom of the steam-water separator of the carbon capture system of the utility model is 40°C, and the carbon dioxide exhaust gas of the compressor is 140°C. After heat exchange, it can be reduced to 50°C, and the heat recovery efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the system of the present utility model.

[0026] The reference numerals in the drawings are shown as follows: 1 - desorption column; 2 - first-stage compressor; 3 - first-stage compressor discharge heat exchanger; 4 - first-stage compressor discharge cooler; 5 - second-stage compressor; 6 - second-stage compressor discharge heat exchanger; 7 - second-stage compressor discharge cooler; 8 - third-stage compressor; 9 - third-stage compressor discharge heat exchanger; 10 - third-stage compressor discharge cooler; 11 - transfer pump; 12 - steam-water separator; 13 - condenser; a - rich liquid; b - lean liquid; c - heated rich liquid; d - rich liquid to be heated; e - carbon dioxide gas; f - carbon dioxide gas at 0.1 MPa and 40 °C; g - carbon dioxide gas at 2.5 MPa and 40 °C. Specific embodiments

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Please refer to Figure 1 , the present invention provides the following technical solutions: An amine-based carbon capture and carbon dioxide compression and liquefaction coupling system, including a desorption column 1, a first-stage compressor 2, a first-stage compressor discharge heat exchanger 3, a first-stage compressor discharge cooler 4, a second-stage compressor 5, a second-stage compressor discharge heat exchanger 6, a second-stage compressor discharge cooler 7, a third-stage compressor 8, a third-stage compressor discharge heat exchanger 9, a third-stage compressor discharge cooler 10, a transfer pump 11, a steam-water separator 12, and a condenser 13;

[0029] The present invention includes a first system, namely a carbon dioxide compression and liquefaction coupling system: The low-pressure and low-temperature gas sequentially passes through the first-stage compressor 2, the first-stage compressor discharge heat exchanger 3, the first-stage compressor discharge cooler 4, the second-stage compressor 5, the second-stage compressor discharge heat exchanger 6, the second-stage compressor discharge cooler 7, the third-stage compressor 8, and the third-stage compressor discharge heat exchanger 9 to obtain a high-pressure and low-temperature gas; among them, the temperature of the compressed gas rises. The temperature reduction in this system is achieved by heat exchange between the low-temperature medium in the heat exchange pipeline of the compressor discharge heat exchanger and the high-temperature flue gas, and the low-temperature medium is the remaining liquid after being condensed by the condenser 13 and separated by the steam-water separator 12 in the second system, the carbon capture system, of the present invention.

[0030] The present invention includes a second system, namely a carbon capture system: The high-temperature water vapor from the desorption column 1 is condensed by the condenser 13 and enters the steam-water separator 12 for steam-water separation. The transfer pump 11 sends the remaining liquid through the first-stage compressor discharge heat exchanger 3, the second-stage compressor discharge heat exchanger 6, and the third-stage compressor discharge heat exchanger 9 into the desorption column 1 for carbon capture.

[0031] In the carbon dioxide compression and liquefaction coupling system, the low-pressure and low-temperature gas is carbon dioxide gas at 0.1 MPa and 40 °C. It is continuously compressed by a compressor, the air pressure rises and the temperature increases, forming a high-temperature and high-pressure gas. It exchanges heat with the carbon capture system in the compressor discharge heat exchanger, then enters the compressor discharge cooler for further cooling, and then enters the next-stage compressor for compression. Finally, carbon dioxide gas at 2.5 MPa and 40 °C is obtained.

[0032] In the carbon capture system, the temperature of the liquid-phase working medium at the bottom of the steam-water separator 12 is 40 °C. The liquid-phase working medium at the bottom is respectively transported to the inter-stage heat exchanger by the transfer pump 11, exchanges heat with the carbon dioxide compression and liquefaction coupling system, absorbs heat, and then re-enters the desorption tower 1 to be mixed with the rich liquid to be heated for heating, obtaining the heated rich liquid. The heated rich liquid is desorbed to obtain high-temperature water vapor and lean liquid.

[0033] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural or equivalent process transformations made by using the content of the specification and drawings of the present invention, or directly or indirectly applied to other related technical fields, are similarly included in the patent protection scope of the present invention.

Claims

1. An amine carbon capture and carbon dioxide compression liquefaction coupling system, characterized in that: It includes a carbon capture system and a carbon dioxide compression and liquefaction coupling system; the carbon capture system is connected to the carbon dioxide compression and liquefaction coupling system via a heat exchange pipeline; The carbon capture system comprises: a desorption tower (1), a condenser (13), a steam-water separator (12), and a delivery pump (11) are sequentially connected along the direction of the flue gas, and are then respectively connected to a first-stage compressor exhaust heat exchanger (3), a second-stage compressor exhaust heat exchanger (6), and a third-stage compressor exhaust heat exchanger (9); the flue gas is high-temperature water vapor from the desorption tower, and the high-temperature water vapor enters the steam-water separator (12) after being cooled by the condenser (13); The carbon dioxide compression and liquefaction coupling system comprises: a first-stage compressor (2), a first-stage compressor exhaust heat exchanger (3), a first-stage compressor exhaust cooler (4), a second-stage compressor (5), a second-stage compressor exhaust heat exchanger (6), a second-stage compressor exhaust cooler (7), a third-stage compressor (8), a third-stage compressor exhaust heat exchanger (9), and a third-stage compressor exhaust cooler (10) which are sequentially connected along the direction of the flue gas.

2. The amine carbon capture and carbon dioxide compression liquefaction coupling system according to claim 1 is characterized in that: The first-stage compressor exhaust heat exchanger (3), the second-stage compressor exhaust heat exchanger (6), and the third-stage compressor exhaust heat exchanger (9) are respectively provided with a first-stage heat exchange pipeline, a second-stage heat exchange pipeline, and a third-stage heat exchange pipeline; The carbon capture system is connected to the carbon dioxide compression and liquefaction coupling system via a heat exchange pipe, wherein the flue gas outlet of the delivery pump (11) is respectively connected along the flue gas direction through the primary heat exchange pipe of the primary compressor exhaust heat exchanger (3), the secondary heat exchange pipe of the secondary compressor exhaust heat exchanger (6), and the tertiary heat exchange pipe of the tertiary compressor exhaust heat exchanger (9), and then connected to the desorption tower (1).

3. The amine carbon capture and carbon dioxide compression liquefaction coupling system according to claim 2 is characterized in that: The delivery pump (11) returns a certain proportion of the residual liquid separated by the steam-water separator (12) to the front end of the desorption tower (1) through the heat exchange pipeline.

4. The amine carbon capture and carbon dioxide compression liquefaction coupling system according to claim 3 is characterized in that: The residual liquid enters the desorption tower (1) and is mixed with the rich liquid to be heated to obtain a heated rich liquid; the heated rich liquid is desorbed to obtain high-temperature water vapor and lean liquid.

5. The amine carbon capture and carbon dioxide compression liquefaction coupling system according to claim 1, characterized in that: The first-stage compressor (2), the second-stage compressor (5), and the third-stage compressor (8) are respectively provided with a first-stage compression pipeline, a second-stage compression pipeline, and a third-stage compression pipeline; The first-stage compressor exhaust cooler (4), the second-stage compressor exhaust cooler (7), and the third-stage compressor exhaust cooler (10) are respectively provided with a first-stage cooling pipeline, a second-stage cooling pipeline, and a third-stage cooling pipeline.

6. The amine carbon capture and carbon dioxide compression liquefaction coupling system according to claim 5, characterized in that: The carbon dioxide compression and liquefaction coupling system further comprises: along the direction of the low-pressure gas, the compressed gas of the first-stage compressor (2) sequentially passes through the first-stage heat exchange pipe of the first-stage compressor exhaust heat exchanger (3) and the first-stage cooling pipe of the first-stage compressor exhaust cooler (4) to enter the second-stage compressor (5) for compression, then sequentially passes through the second-stage heat exchange pipe of the second-stage compressor exhaust heat exchanger (6) and the second-stage cooling pipe of the second-stage compressor exhaust cooler (7) to enter the third-stage compressor (8) for compression, and finally passes through the third-stage heat exchange pipe of the third-stage compressor exhaust heat exchanger (9) and the third-stage cooling pipe of the third-stage compressor exhaust cooler (10) to be discharged; The gas is low-pressure and low-temperature carbon dioxide gas; the exhausted flue gas is high-pressure and low-temperature carbon dioxide gas.

7. The amine carbon capture and carbon dioxide compression liquefaction coupling system according to claim 1, characterized in that: The steam-water separator (12) separates the high-temperature water vapor into carbon dioxide gas and the remaining liquid phase working fluid.

8. The amine carbon capture and carbon dioxide compression liquefaction coupling system according to claim 1, characterized in that: The first-stage compressor exhaust heat exchanger (3), the second-stage compressor exhaust heat exchanger (6) and the third-stage compressor exhaust heat exchanger (9) are all inter-stage heat exchangers, and the inter-stage heat exchangers adopt shell and tube / plate heat exchange.

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