Carbon dioxide capture system and method

Abstract

The invention provides a carbon dioxide trapping system and method. The carbon dioxide trapping system comprises a gas compression tower, a membrane separation assembly, a CO2 absorption tower, a regeneration tower and a condensation assembly, the gas compression tower is used for compressing mixed gas mixed with CO2 and O2, the compressed mixed gas passes through the membrane separation assembly to obtain permeation gas of enriched CO2 gas, and a smoke outlet is formed in the top of the gas compression tower; the CO2 absorption tower is provided with a spraying part, an organic amine solvent sprayed by the spraying part is used for absorbing CO2 gas in permeation gas to generate amine-rich liquid, the CO2 absorption tower is communicated with the regeneration tower, the regeneration tower is provided with a heating part, the heating part is used for heating the amine-rich liquid in the regeneration tower to generate CO2 gas, the regeneration tower is communicated with the condensation assembly, and the condensation assembly is used for condensing the CO2 gas. The condensation assembly is further communicated with a gas outlet, and the gas outlet is used for discharging gas. By implementing the carbon dioxide trapping system, the problem of oxidative degradation of the organic amine chemical absorbent in the process of absorbing carbon dioxide can be solved.

Description

Technical Field

[0001] The present invention relates to the field of carbon dioxide recovery, and particularly to a carbon dioxide capture system and method. Background Art

[0002] The organic amine chemical absorption method for carbon capture technology is widely used in flue gas carbon dioxide capture. Compared with other technologies, it has high capture efficiency and can obtain nearly pure CO2 products. However, during the carbon capture process, the flue gas contains oxygen and other impurity gases (such as SOx and NOx). During the absorption process, the organic amine chemical absorbent is prone to oxidation reactions with oxygen and other impurity gases, generating degradation products such as ammonia, aldehydes, ketones, alcohols, acids, piperazines, imidazolidinones, etc., resulting in the loss of the ability of the organic amine chemical absorbent to continue absorbing CO2, affecting the stability and service life of the organic amine chemical absorbent. Therefore, the capture of CO2 in flue gas by the organic amine chemical absorption method will face the problem of degradation of the organic amine solution. Among them, the degradation caused by the reaction of organic amine with oxygen in the flue gas plays a dominant role, accounting for about 70% of the total degradation of organic amine, seriously hindering the progress of the organic amine chemical absorption method for carbon capture technology in the application of flue gas carbon dioxide capture at present.

[0003] To reduce the impact of oxidative degradation on the organic amine chemical absorption method for carbon capture, the general solution is to add antioxidants to the organic amine absorption solution. However, the addition of antioxidants can only alleviate the degradation rate of organic amine and cannot fundamentally solve the problem of oxidative degradation of organic amine. Therefore, there is an urgent need to provide an effective measure and method to solve the oxidative degradation of the organic amine chemical absorbent during the flue gas carbon dioxide capture process. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a carbon dioxide capture system and method to solve the problem of oxidative degradation of the organic amine chemical absorbent during the process of absorbing carbon dioxide.

[0005] In a first aspect, in one embodiment, a carbon dioxide capture system is provided, including a gas compression tower, a membrane separation module, a CO2 absorption tower, a regeneration tower, and a condensation module;

[0006] The gas compression tower is used to compress the mixed gas containing CO2 and O2. After passing through the membrane separation module, the compressed mixed gas obtains a permeate gas of enriched CO2 gas. A smoke exhaust port is provided at the top of the gas compression tower, and the smoke exhaust port is used to discharge the retentate gas;

[0007] The CO2 absorption tower is provided with a spraying member. The organic amine solvent sprayed by the spraying member absorbs the CO2 gas in the permeate gas to generate a rich amine solution. The CO2 absorption tower is connected to the regeneration tower. The regeneration tower is provided with a heating member for heating the rich amine solution in the regeneration tower to generate CO2 gas. The regeneration tower is connected to the condensation assembly, and the condensation assembly is also connected to a gas outlet for discharging CO2.

[0008] As a further optional solution of the carbon dioxide capture system, the membrane separation module is provided with packing on one side close to the spraying member, and the packing is used for mutual absorption of the permeate gas and the organic amine solution.

[0009] In a second aspect, an embodiment provides a carbon dioxide capture method, which includes the following steps:

[0010] S1. Compress the mixed gas containing CO2 and O2 and introduce it into the membrane separation module. After passing through the membrane separation module, a permeate gas with a higher CO2 content is obtained.

[0011] S2. Introduce the permeate gas into the CO2 absorption tower. The spraying member in the CO2 absorption tower sprays the organic amine solution, and the organic amine solution absorbs the permeate gas to form a rich amine solution.

[0012] S3. Introduce the rich amine solution into the regeneration tower. The regeneration tower heats the rich amine solution, and the rich amine solution desorbs CO2 gas.

[0013] S4. Condense and separate the desorbed CO2 gas to obtain CO2 gas.

[0014] As a further optional solution of the carbon dioxide capture method, step S1 further includes cooling the mixed gas and separating the liquid obtained after cooling.

[0015] As a further optional solution of the carbon dioxide capture method, in step S1, the cooling temperature is 40°C to 50°C.

[0016] As a further optional solution of the carbon dioxide capture method, in step S1, the molar ratio range of O2 and CO2 in the mixed gas is 0.35 to 0.45.

[0017] As a further optional solution of the carbon dioxide capture method, in step S1, the molar ratio range of O2 and CO2 in the permeate gas is 0.15 to 0.25.

[0018] As a further optional scheme of the carbon dioxide capture method, in the step S1, the pressure range of the compressed mixed gas is 0.1 MPa to 1.0 MPa.

[0019] As a further optional solution of the carbon dioxide capture method, in the step S3, the desorbed rich amine liquid is refluxed through the pipeline and sprayed out from the spraying member.

[0020] As a further optional scheme of the carbon dioxide capture method, in the step S3, the rich amine liquid is heated to a temperature of 104-120°C.

[0021] As a further optional scheme of the carbon dioxide capture method, the organic amine solution is ethanolamine.

[0022] Implementing the embodiments of the present invention will have the following beneficial effects:

[0023] According to the carbon dioxide capture system in the above embodiment, the density and pressure of the mixed gas increase after being compressed by the compression tower. The compressed gas is on one side of the membrane separation component, and the other side is connected to the CO2 absorption tower. Due to the pressure difference on both sides of the membrane separation component, the membrane separation component allows CO2 gas to pass through and isolates other gases. In the CO2 absorption tower, the spray part sprays the organic amine solvent, and the organic amine solvent absorbs the CO2 gas, so that the membrane separation component always maintains a relatively low pressure on the side close to the CO2 absorption tower. After the organic amine solvent absorbs the CO2 gas, a rich amine liquid is formed. The rich amine liquid is introduced from the CO2 absorption tower to the regeneration tower. The heating element in the regeneration tower heats the rich amine liquid, thereby re-analyzing the CO2 gas. Finally, the derived CO2 gas is condensed by the condensation component, and the liquid is removed to discharge the obtained CO2 gas from the gas outlet. In the gas compression tower, most of the compressed O2 and N2 are discharged from the smoke exhaust port. The implementation of the carbon dioxide capture system in the present invention can solve the problem of oxidative degradation of the organic amine chemical absorbent during the absorption of carbon dioxide.

[0024] According to the carbon dioxide capture method in the above embodiment, by compressing the mixed gas and using a membrane separation component, the organic amine solution is excluded from oxidation reaction with oxygen and other impurity gases during the process of capturing carbon dioxide, thereby avoiding oxidative degradation of the organic amine. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Wherein:

[0027] Figure 1 shows a schematic diagram of the principle of a carbon dioxide capture system provided according to an embodiment of the present invention;

[0028] Figure 2 shows the experimental data of a carbon dioxide capture system provided according to an embodiment of the present invention.

[0029] Description of main component symbols:

[0030] Gas compression tower - 10; CO2 absorption tower - 20; Membrane separation module - 30; Spraying part - 40; Regeneration tower - 50; Condensation module - 60; Circulation module - 70; Liquid pump - 710; Compressor - 110. Detailed implementation manners

[0031] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the understanding of the disclosure of the present invention is more thorough and comprehensive.

[0032] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0034] In an embodiment of the present invention, a carbon dioxide capture system and method are provided. Please refer to Figure 1 , the carbon dioxide capture system includes a gas compression tower 10, a membrane separation module 30, a CO2 absorption tower 20, a regeneration tower 50, and a condensation module 60;

[0035] The gas compression tower 10 is used to compress the mixed gas containing CO2 and O2. After the compressed mixed gas passes through the membrane separation module 30, the permeate gas of the enriched CO2 gas is obtained. A smoke exhaust port is provided at the top of the gas compression tower 10, and the smoke exhaust port is used to discharge the retentate gas;

[0036] The CO2 absorption tower 20 is provided with a spraying member 40. The organic amine solvent sprayed by the spraying member 40 absorbs the CO2 gas in the permeate gas to generate a rich amine solution. The CO2 absorption tower 20 is connected to the regeneration tower 50. The regeneration tower 50 has a heating member (not shown in the figure), and the heating member is used to heat the rich amine solution in the regeneration tower 50 to generate CO2 gas. The regeneration tower 50 is connected to the condensation module 60, and the condensation module 60 is also connected to the gas outlet. The gas outlet (not shown in the figure) is used to discharge CO2.

[0037] According to the carbon dioxide capture system in the above embodiments, the density and pressure of the mixed gas become larger after being compressed by the compression tower. The compressed gas is on one side of the membrane separation module 30, and the other side is connected to the CO2 absorption tower 20. Due to the pressure difference on both sides of the membrane separation module 30, the membrane separation module 30 allows the CO2 gas to pass through and isolates other gases. In the CO2 absorption tower 20, the spraying member 40 sprays the organic amine solvent, and the organic amine solvent absorbs the CO2 gas, so that the side of the membrane separation module 30 close to the CO2 absorption tower 20 always maintains a relatively low pressure. After the organic amine solvent absorbs the CO2 gas, a rich amine solution is formed. The rich amine solution is introduced from the CO2 absorption tower 20 into the regeneration tower 50, and the heating member in the regeneration tower 50 heats the rich amine solution, thereby re-analyzing the CO2 gas. Finally, the exported CO2 gas is condensed by the condensation module 60 to remove the liquid, and the obtained CO2 gas is discharged from the gas outlet. In the gas compression tower 10, most of the compressed O2 and N2 are discharged from the smoke exhaust port. Implementing the carbon dioxide capture system of the present invention can solve the problem of oxidative degradation of the amine chemical absorbent during the process of absorbing carbon dioxide.

[0038] The gas compression tower 10 generally includes a compressor 110 and a condensation module 60. Among them, the compressor 110 is mainly used to compress the mixed gas.

[0039] In some specific embodiments, a filler is provided on the side of the membrane separation module 30 close to the spraying member 40, and the filler is used for mutual absorption of the permeate gas and the organic amine solution.

[0040] Due to the effect of the filler, the contact area between the organic amine solution and the CO2 gas is increased, and the contact time is prolonged, so as to achieve the purpose of better absorbing the CO2 gas.

[0041] It should be noted that the condensation module 60 is arranged between the gas compression tower 10 and the CO2 absorption tower 20 to remove the water in the mixed gas.

[0042] The carbon dioxide capture system in this embodiment further includes a circulation component 70, and the circulation component 70 mainly makes full use of thermal energy. Specifically, in the regeneration tower 50, the rich amine solution releases carbon dioxide gas after heating and is reduced to an organic amine solution. At this time, the temperature of the organic amine solution in the regeneration tower 50 is still very high and it is difficult to absorb carbon dioxide gas. Through the liquid pump 710, the organic amine solution in the regeneration tower 50 is heat-exchanged with the rich amine solution that is about to enter the regeneration tower 50, so as to realize preheating of the rich amine solution and precooling of the organic amine solution.

[0043] Specifically, the organic amine solution from which carbon dioxide gas is regenerated is generally called lean amine solution. The rich amine solution is generally pumped into a liquid storage tank in the circulation component by the liquid pump 710, and the pipeline of the lean amine solution spirally penetrates through the liquid storage tank, and the lean amine solution is made to flow through the liquid storage tank by another liquid pump 710. Such an arrangement can not only realize precooling of the lean amine solution, but also realize preheating of the rich amine solution.

[0044] Alternatively, the rich amine solution is generally pumped into the circulation component 70 by the liquid pump from the cold medium inlet, and the lean amine solution is pumped into the circulation component 70 by the liquid pump 710 from the hot medium inlet. The lean amine solution and the rich amine solution are separated by a partition in the circulation component 70, and the lean / rich amine solutions exchange heat countercurrently on both sides of the partition. Such an arrangement can not only realize precooling of the lean amine solution, but also realize preheating of the rich amine solution.

[0045] A condensation component 60 is further provided between the circulation component 70 and the spraying component 40, and the condensation component 60 is used to further cool the precooled organic amine solution, so as to better absorb CO2 gas.

[0046] Example 1:

[0047] A mixed gas with a carbon dioxide molar concentration of 14% is used, and the ratio of O2(mol):CO2(mol) in the mixed gas is 0.4. Then the mixed gas is fed into the gas compression tower 10, pressurized to 1 MPa, cooled to 40 °C by the condensation assembly 60, and then subjected to gas-liquid separation. The main cost of the liquid is water. The separated gas enters the membrane separation module 30, is cooled to 40 °C and then subjected to gas-liquid separation. The main cost of the liquid is water. The separated gas enters the membrane separation module 30. The membrane separation module 30 has the characteristics of preferential and rapid permeation of carbon dioxide, reducing the oxygen content on the permeate side. Driven by the pressure difference on both sides of the membrane separation module 30, carbon dioxide preferentially and rapidly permeates through the membrane, and the carbon dioxide concentration is enriched on the downstream side, obtaining a permeate gas with a carbon dioxide molar concentration of 50% and O2(mol):CO2(mol) of 0.2. On the permeate side, carbon dioxide is absorbed by using an ethanolamine (MEA) solution with a mass fraction of 35% through an organic amine solution spraying device. The rich amine solution saturated with CO2 enters the regeneration tower 50 and is desorbed at a temperature of 110 °C to regenerate CO2 gas. The regenerated CO2 gas is condensed and separated to obtain a carbon dioxide product gas with a purity of 98.6% (dry basis). The unabsorbed residual gas on the permeate side of the membrane separation module 30 is discharged through the flue at the top of the CO2 absorption tower 20, and the measured inorganic ammonia escape concentration at the flue outlet is 2 ppm. On the pressure side of the membrane separation module 30, most of the oxygen and nitrogen are discharged as the retentate gas from the smoke exhaust port.

[0048] Comparative Example 1:

[0049] Compared with Example 1, the difference is that only the organic amine method is used to capture carbon dioxide.

[0050] A mixed gas with a carbon dioxide molar concentration of 14% and O2(mol):CO2(mol) of 0.4 is fed into the CO2 absorption tower 20. A spraying part 40 is arranged in the CO2 tower, and the spraying part 40 sprays an ethanolamine (MEA) solution with a mass fraction of 35% to absorb carbon dioxide. After the ethanolamine (MEA) solution is saturated with absorption, it forms a rich amine solution and enters the regeneration tower 50. The rich amine solution is desorbed at a temperature of 110 °C, and the regenerated gas is condensed and separated to obtain a carbon dioxide product gas with a purity of 98.3% (dry basis). The unabsorbed residual gas in the CO2 absorption tower 20 is discharged through the flue at the top, and the measured inorganic ammonia escape concentration at the flue outlet is 28 ppm. Similarly, on the pressure side of the membrane separation module 30, most of the oxygen and nitrogen are discharged as the retentate gas from the smoke exhaust port.

[0051] Example 2:

[0052] A mixed gas containing 14% (mol) of carbon dioxide and with an O2(mol):CO2(mol) ratio of 0.4 is pressurized to 1 MPa by a compressor and then enters a condensing assembly 60. After being cooled to 40 °C, it undergoes gas-liquid separation. The separated gas enters a membrane separation assembly 30. Driven by the pressure difference on both sides of the membrane separation assembly 30, carbon dioxide preferentially and rapidly permeates through the membrane, and the carbon dioxide concentration is enriched in the downstream side CO2 absorption tower 20, obtaining a permeate gas with a carbon dioxide molar concentration of 50% and an O2(mol):CO2(mol) ratio of 0.2. In the CO2 absorption tower 20 on the permeate side of the membrane separation assembly 30, a 35% (mass fraction) diethanolamine (MDEA) solution is sprayed through a spraying member 40 to absorb carbon dioxide. The rich amine solution after the MDEA is saturated with absorption enters a regeneration tower 50. The rich amine solution is desorbed at a temperature of 110 °C, and the regenerated CO2 gas undergoes condensation and separation to obtain a carbon dioxide product gas with a purity of 98.2% (dry basis). The unabsorbed residual gas on the permeate side of the membrane separation assembly 30 is discharged through the flue at the top, and the measured inorganic ammonia escape concentration at the flue outlet is 24 ppm. On the pressure side of the membrane separation assembly 30, most of the oxygen and nitrogen are discharged as retentate gas from the smoke exhaust port.

[0053] Comparative Example 2:

[0054] Compared with Example 2, the difference lies in that only the organic amine method is used to capture carbon dioxide.

[0055] A method for capturing carbon dioxide using the organic amine method, comprising the following steps:

[0056] A raw material gas containing 14% (mol) of carbon dioxide and with an O2(mol):CO2(mol) ratio of 0.4 enters a CO2 absorption tower 20. A spraying member 40 is provided in the CO2 absorption tower 20, and a 35% (mass fraction) diethanolamine (MDEA) solution is sprayed by the spraying member 40 to absorb carbon dioxide. The rich amine solution saturated with absorption enters a regeneration tower 50. The rich amine solution is desorbed at a temperature of 110 °C, and the regenerated carbon dioxide gas undergoes condensation and separation to obtain a carbon dioxide product gas with a purity of 98.1% (dry basis). The unabsorbed residual gas in the CO2 absorption tower 20 is discharged through the flue at the top, and the measured inorganic ammonia escape concentration at the flue outlet is 295 ppm. On the pressure side of the membrane separation assembly 30, most of the oxygen and nitrogen are discharged as retentate gas from the smoke exhaust port.

[0057] In the above four examples, please refer to Figure 2, monoethanolamine (MEA, primary amine) and N-methyldiethanolamine (MDEA, tertiary amine) with a wide range of application bases and high CO2 absorption capacities are selected as experimental solvents. The main products of the oxidative degradation of the above two solvents are inorganic ammonia, and the degree of oxidative degradation of the solvents can be accurately evaluated by measuring the concentration of inorganic ammonia in the flue of the CO2 absorption tower 20.

[0058] It should be noted that in Embodiment 1 and Embodiment 2, the water condensed in the condensing assembly 60 generally flows back to the spraying member 40 through a pump to prevent large changes in the concentration of the organic amine solution.

[0059] The membrane separation assembly 30 mainly includes a gas separation membrane and a packing. Among them, the side of the membrane separation assembly 30 facing the compressed gas is the pressure side, and the side of the membrane separation assembly 30 facing the CO2 absorption tower 20 is the permeation side. The packing is located on the permeation side, and the main function of the packing is to increase the contact area between the organic amine solution and the permeating gas and improve the absorption effect of the organic amine absorption solution on carbon dioxide.

[0060] The carbon dioxide gas separation membrane is a membrane material that separates carbon dioxide from a gas mixture based on physical or chemical principles through the pores or selective permeability of the membrane. This membrane technology has the advantages of high efficiency, energy saving, environmental protection, etc. Preferably, the gas separation membrane can be made of materials such as silicone oxide membranes, polymer membranes, and porous inorganic membranes.

[0061] The gas compression tower 10 is mainly realized by a gas compressor, and the mixed gas mainly comes from the tail gas emissions of steel mills and power plants, etc.

[0062] The principle of organic amine absorbing carbon dioxide is mainly chemical absorption.

[0063] Chemical absorption refers to the chemical reaction between organic amine and carbon dioxide to form a stable compound. Common organic amine absorbents include monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), etc. These amine compounds are usually dissolved in water to form an alkaline solution, which can react with carbon dioxide to form carbamate or bicarbonate. The reactions are as follows:

[0064] 2NH2CH2CH2OH + CO2 → NH2CH2CH2OOCNHCH2CH2OH + H2O;

[0065] NH2CH2CH2OH + CO2 + H2O → NH2CH2CH2OH·HCO3- + H+.

[0066] The above chemical absorption and physical absorption will both undergo reverse reactions after heating, thereby releasing CO2 gas. The heating temperature is generally between 104°C and 120°C. The reverse reaction generally occurs in the regeneration tower 50. The regeneration tower 50 is equipped with a heating element, and the regeneration tower 50 is heated by the heating element to meet the conditions for the reverse reaction.

[0067] Since the temperature of the reverse reaction is above 100°C, the desorbed gas must contain a large amount of water vapor. Through the condensation component 60, the water vapor therein is condensed and liquefied, thereby obtaining a higher-concentration CO2 gas.

[0068] Generally, the mixed gas will be overheated after compression. Therefore, it is necessary to cool the compressed mixed gas. The temperature of the cooled gas is preferably 40°C to 50°C. The water vapor in the compressed and cooled mixed gas is basically liquefied. At this time, the liquefied water needs to be removed to avoid diluting the organic amine solution.

[0069] Before the mixed gas is compressed, the molar ratio range of O2 to CO2 is 0.35 to 0.45, preferably 0.4. The molar ratio of O2 to CO2 in the permeate gas on the permeate side is generally between 0.15 and 0.25. It can be seen from this that the CO2 content in the permeate gas is higher than that in the mixed gas, while the O2 content is lower. This can extend the service life of the organic amine solution. In the regeneration tower 50, after the CO2 gas is desorbed, the remaining liquid needs to be re-introduced into the spraying component 40, so as to realize the purification of CO2 in a cycle. Exactly speaking, the rich amine liquid at this time changes back to the organic amine solution.

[0070] The conventional atmospheric pressure is about 10KPa, and the pressure of the compressed mixed gas between 0.1MPa and 1.0MPa can achieve the rapid permeation of CO2 gas.

[0071] Finally, it can be seen from the comparison between Example 1 and Example 3 that ethanolamine (MEA) has a stronger antioxidant effect compared with diethanolamine (MDEA). Ethanolamine (MEA) can be recycled more times, thereby reducing production costs.

[0072] Moreover, it can be seen from the comparison between Example 1 and Comparative Example 1, and the comparison between Example 2 and Comparative Example 2 that the organic ammonia solution after compression and processed through the membrane separation component 30 process is significantly less oxidized and degraded.

[0073] Judging from the data, after the same ethanolamine is processed by the process of the present invention, the oxidative degradation of ethanolamine is reduced by 92.8%. After the same diethanolamine (MDEA) is processed by the process of the present invention, the oxidative degradation of diethanolamine (MDEA) is reduced by 91.8%.

[0074] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as falling within the scope described in this specification.

[0075] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A carbon dioxide capture system, characterized in that, It includes a gas compression tower, a membrane separation module, a CO2 absorption tower, a regeneration tower, and a condensation module; The gas compression tower is used to compress the mixed gas containing CO2 and O2. After passing through the membrane separation module, the compressed mixed gas obtains the permeate gas of enriched CO2 gas. A smoke exhaust port is provided at the top of the gas compression tower, and the smoke exhaust port is used to discharge the retentate gas; The CO2 absorption tower is provided with a spraying member. The organic amine solvent sprayed by the spraying member absorbs the CO2 gas in the permeate gas to generate a rich amine solution. The CO2 absorption tower is connected to the regeneration tower. The regeneration tower has a heating member, and the heating member is used to heat the rich amine solution in the regeneration tower to generate CO2 gas. The regeneration tower is connected to the condensation module, and the condensation module is also connected to a gas outlet, and the gas outlet is used to discharge CO2.

2. The carbon dioxide capture system according to claim 1, characterized in that, The membrane separation module is provided with packing on one side close to the spraying member, and the packing is used for mutual absorption of the permeate gas and the organic amine solution.

3. A method for carbon dioxide capture as described in any one of claims 1 or 2, characterized in that, This method includes the following steps: S1. Compress the mixed gas containing CO2 and O2 and then introduce it into the membrane separation module. After passing through the membrane separation module, the mixed gas obtains a permeate gas with a higher CO2 content; S2. Introduce the permeate gas into the CO2 absorption tower. The spraying member in the CO2 absorption tower sprays the organic amine solution, and the organic amine solution absorbs the permeate gas to form a rich amine solution; S3. Introduce the rich amine solution into the regeneration tower. The regeneration tower heats the rich amine solution, and the rich amine solution desorbs CO2 gas; S4. Condense and separate the desorbed CO2 gas to obtain CO2 gas.

4. The method for carbon dioxide capture according to claim 3, characterized in that, The step S1 further includes cooling the mixed gas and separating the liquid obtained after cooling.

5. The method for carbon dioxide capture according to claim 4, wherein In the step S1, the cooling temperature is 40°C to 50°C.

6. The method for carbon dioxide capture according to claim 3, wherein In the step S1, the molar ratio range of O2 and CO2 in the mixed gas is 0.35 to 0.

45.

7. The method for carbon dioxide capture according to claim 3, wherein In the step S1, the molar ratio range of O2 and CO2 in the permeate gas is 0.15 to 0.

25.

8. The method for carbon dioxide capture according to claim 3, characterized in that, In the step S1, the pressure range after compression of the mixed gas is 0.1 MPa to 1.0 MPa.

9. The method for carbon dioxide capture according to claim 3, wherein, In the step S3, the desorbed rich amine solution returns through a pipeline and is sprayed out from the spraying member.

10. The method for carbon dioxide capture according to claim 3, wherein, In the step S3, the heating temperature of the rich amine solution is 104 to 120°C.

11. The method for carbon dioxide capture according to claim 3, characterized in that, The organic amine solution is ethanolamine.

Images