A membrane separation device and an engine exhaust device

Abstract

This invention relates to the field of environmental protection technology and discloses a membrane separation device and an engine exhaust device. The first-stage separation membrane assembly includes a first cylindrical membrane and a first cylindrical membrane disposed within it. The inner diameter side of the first cylindrical membrane and the axial inner side of the first cylindrical membrane form a first space, which is an intake space. The axial outer side of the first cylindrical membrane forms a third space, and the outer diameter side of the first cylindrical membrane forms a second space. The second-stage separation membrane assembly includes a second cylindrical membrane and a second cylindrical membrane disposed within it. The axial inner side of the second cylindrical membrane and the axial inner side of the second cylindrical membrane form a third space. The outer diameter side of the second cylindrical membrane forms a second space. The axial outer side of the second cylindrical membrane forms a fourth space, and the axial outer side of the second cylindrical membrane forms a fifth space. The fourth and fifth spaces are exhaust spaces. This invention allows for four flow paths from the intake space to the exhaust space, facilitating the flow of different gas components and ultimately separating the desired gas.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology, and in particular to a membrane separation device and an engine exhaust device. Background Technology

[0002] In the global transportation sector, with rapid economic development and continuous population growth, the number of vehicles has exceeded one billion. Although the carbon emissions produced by each vehicle's engine when running individually are relatively small, the sheer number of vehicles results in a significant overall carbon emissions, severely impacting the global climate and environment. Therefore, effectively controlling and reducing carbon emissions in the transportation sector has become a crucial and urgent issue that needs to be addressed.

[0003] For the capture of CO2 emissions, a variety of methods have been researched and applied, mainly including solvent absorption, low temperature separation, membrane separation technology and adsorption separation.

[0004] Solvent absorption utilizes the differences in solubility of different solutes in solvents to separate and purify target substances by selecting appropriate solvents. However, this method may face challenges in practical applications, such as solvent selection, recovery, and treatment.

[0005] Cryogenic separation, also known as deep cryogenic separation, is based on the differences in boiling points of different substances. It purifies and recovers CO2 from a gas mixture through low-temperature liquefaction and separate distillation. However, this method is energy-intensive and has high equipment costs, making it difficult to achieve large-scale production and limiting its widespread application.

[0006] Membrane separation technology separates components in a mixture based on the different permeabilities of the membrane. With the continuous development of membrane synthesis technology, membrane separation has shown broad application prospects in CO2 capture. Common CO2 gas separation membrane materials include organic membranes such as polyethylene oxide and polyphenylene ether, as well as composite materials such as MOFs (Metal-Organic Frameworks), carbon membranes, and mixed matrix membranes. However, issues related to the performance, stability, and cost of membrane materials still require further research and solutions.

[0007] Adsorption separation utilizes the difference in the interaction strength between the adsorbent and the mixed gas under different operating conditions to achieve separation and purification. Depending on the operating conditions, adsorption separation methods can be divided into temperature swing adsorption (TSA) and pressure swing adsorption (PSA). Among them, pressure swing adsorption is widely used in the gas adsorption and separation industry due to its advantages such as low energy requirement, simple operation process, and short adsorbent regeneration cycle. For example, in flue gas separation, CO2 capture mostly adopts pressure swing adsorption separation technology.

[0008] However, current CO2 capture methods are mainly applied to large-scale energy equipment such as coal-fired power plants, which consume large amounts of fossil fuels and have high concentrated CO2 emissions. For mobile and decentralized energy equipment, such as vehicles and other transportation vehicles, due to the complexity and diversity of their operating environments, there are currently no effective CO2 capture technologies applicable to this area. In particular, regarding engine carbon emission control, current efforts mainly focus on the combustion and utilization of fossil fuels, while technological research and development targeting the post-combustion CO2 exhaust emission stage remains lacking. Summary of the Invention

[0009] The purpose of this invention is to provide a membrane separation device and an engine exhaust device to solve the problems existing in the prior art. Four flow paths can be formed from the intake space to the exhaust space. Multiple flow paths can be used to flow different gas components, and finally the gas to be separated is separated.

[0010] To achieve the above objectives, the present invention provides the following solution:

[0011] This invention provides a membrane separation device, including a primary separation membrane assembly and a secondary separation membrane assembly. The primary separation membrane assembly includes a first cylindrical membrane and a first cylindrical membrane. The first cylindrical membrane is disposed on the inner diameter side of the first cylindrical membrane and near its end. The inner diameter side of the first cylindrical membrane and the axial inner side of the first cylindrical membrane form a first space, which is an air inlet space. The axial outer side of the first cylindrical membrane forms a third space, and the outer diameter side of the first cylindrical membrane forms a second space. The secondary separation membrane assembly includes a second cylindrical membrane and a second cylindrical membrane. The second cylindrical membrane is disposed on the inner diameter side of the second cylindrical membrane. The axial inner side of the second cylindrical membrane and the axial inner side of the second cylindrical membrane form the third space. The outer diameter side of the second cylindrical membrane forms the second space. The axial outer side of the second cylindrical membrane forms a fourth space, and the axial outer side of the second cylindrical membrane forms a fifth space. The fourth space and the fifth space are exhaust spaces.

[0012] In one embodiment, the radially inner surface of the first cylindrical membrane is modified to be an H2O-friendly surface layer, and the radially outer surface is modified to be an H2O-repellent surface layer; the axially inner surface of the first cylindrical membrane is modified to be an H2O-repellent surface layer, and the axially outer surface is modified to be a CO2-friendly surface layer; the axially inner surface of the second cylindrical membrane is modified to be an H2O-friendly surface layer; and the axially inner surface of the second cylindrical membrane is modified to be a CO2-friendly surface layer, and the radially inner surface is modified to be a CO2-friendly surface layer.

[0013] In one embodiment, the radially inner surface of the first cylindrical membrane is made of modified nano-silica, and the radially outer surface is made of modified graphite nanomaterial; the axially inner surface of the first cylindrical membrane is made of modified graphite nanomaterial, and the axially outer surface is made of modified graphene nanomaterial; the axially inner surface of the second cylindrical membrane is made of modified nano-silica; the axially inner surface of the second cylindrical membrane is made of modified graphene nanomaterial, and the radially inner surface is made of modified graphene nanomaterial.

[0014] In one embodiment, the inner diameter of the first cylindrical membrane, the outer diameter of the first cylindrical membrane, and the outer diameter of the second cylindrical membrane are equal.

[0015] In one embodiment, the end faces of the second cylindrical membrane and the second columnar membrane are flush, and the axial length of the second cylindrical membrane and the axial length of the second columnar membrane are equal.

[0016] In one embodiment, the main housing includes an outer housing and an inner housing that are nested together. The inner diameter side of the inner housing is the third space, and the space between the inner wall of the outer housing and the outer wall of the inner housing is the second space. The inlet end of the outer housing is provided with the first space, and the outlet end of the outer housing is provided with the fourth space and the fifth space.

[0017] In one embodiment, the system further includes an outlet pipe, which comprises an inner pipe and an outer pipe nested together. The inner diameter side of the inner pipe is the fifth space, and the space between the inner wall of the outer pipe and the outer wall of the inner pipe is the fourth space.

[0018] In one embodiment, the device further includes a first pressure sensor, a second pressure sensor, a third pressure sensor, a fourth pressure sensor, and a fifth pressure sensor. The first pressure sensor is disposed in the first space, the second pressure sensor is disposed in the second space, the third pressure sensor is disposed in the third space, the fourth pressure sensor is disposed in the fourth space, and the fifth pressure sensor is disposed in the fifth space.

[0019] In one embodiment, a first temperature sensor and a second temperature sensor are also included, the first temperature sensor being disposed in the first space and the second temperature sensor being disposed in the fourth space and / or the fifth space.

[0020] The present invention provides an engine exhaust device, including an exhaust pipe for connection to an engine and a membrane separation device as described above, wherein a first space communicates with the exhaust pipe.

[0021] The present invention achieves the following technical effects compared to the prior art:

[0022] This invention utilizes a primary separation membrane module and a secondary separation membrane module to divide the space into a first space, a second space, a third space, a fourth space, and a fifth space. Four flow paths can be formed from the intake space to the exhaust space: sequentially from the first space, the second space to the fourth space, sequentially from the first space, the second space to the fifth space, sequentially from the first space, the third space to the fourth space, and sequentially from the first space, the third space to the fifth space. Multiple flow paths can be used to flow different gas components, ultimately enabling the separation of the gas to be separated (e.g., CO2).

[0023] This invention is applicable to CO2 capture in mobile and distributed energy equipment such as transportation vehicles, and is of great significance for effectively controlling and reducing carbon emissions in the transportation sector. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall structure of the engine exhaust device in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the membrane separation device in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the first cylindrical membrane in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the first cylindrical membrane in an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the second cylindrical membrane in an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the second cylindrical membrane in an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the membrane separation device in an embodiment of the present invention;

[0032] The components are as follows: 1. Exhaust pipe; 2. First cylindrical membrane; 21. First hydrophobic layer; 22. First hydrophilic layer; 3. First cylindrical membrane; 31. Second hydrophobic layer; 32. First carbon dioxide-loving layer; 4. Second cylindrical membrane; 41. Second hydrophilic layer; 5. Second cylindrical membrane; 51. Second carbon dioxide-loving layer; 52. Third carbon dioxide-loving layer; 6. Fourth space; 7. Fifth space; 8. Third space; 9. Second space; 10. First space; 11. First pressure sensor; 12. Second pressure sensor; 13. Third pressure sensor; 14. Fourth pressure sensor; 15. Fifth pressure sensor; 16. First temperature sensor; 17. Second temperature sensor; 18. Outer shell; 19. Inner shell; 23. Pollutant emission control system; 24. Outer pipe; 25. Inner pipe; 26. Engine; 110. Primary separation membrane assembly; 120. Secondary separation membrane assembly. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The purpose of this invention is to provide a membrane separation device and an engine exhaust device to solve the problems existing in the prior art. Four flow paths can be formed from the intake space to the exhaust space. Multiple flow paths can be used to flow different gas components, and finally the gas to be separated is separated.

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] like Figures 1 to 7As shown, the present invention provides a membrane separation device, including a primary separation membrane assembly 110 and a secondary separation membrane assembly 120. The primary separation membrane assembly 110 includes a first cylindrical membrane 2 and a first cylindrical membrane 3. The first cylindrical membrane 2 can be a cylindrical separation membrane, and the first cylindrical membrane 3 can be a cylindrical separation membrane. The first cylindrical membrane 3 is disposed on the inner diameter side of the first cylindrical membrane 2 and near its end. Thus, a first space 10 can be formed on the inner diameter side of the first cylindrical membrane 2 and the axially inner side of the first cylindrical membrane 3. The first space 10 is an intake space for connecting the exhaust pipe 1 of the engine 26 to the air source awaiting processing. It should be noted that the axially inner side mentioned here and thereafter refers to the side near the intake space, and the axially outer side refers to the side near the exhaust space. The axially outer side of the first cylindrical membrane 3 is the third space 8, and the outer diameter side of the first cylindrical membrane 2 is the second space 9. The secondary separation membrane assembly 120 includes a second cylindrical membrane 4 and a second columnar membrane 5. The second cylindrical membrane 4 can be a separation membrane with a cylindrical structure, and the second columnar membrane 5 can be a separation membrane with a cylindrical structure. The second columnar membrane 5 is disposed on the inner diameter side of the second cylindrical membrane 4. The axial inner side of the second cylindrical membrane 4 and the axial inner side of the second columnar membrane 5 form a third space 8. The outer diameter side of the second cylindrical membrane 4 forms a second space 9. The axial outer side of the second cylindrical membrane 4 forms a fourth space 6. The axial outer side of the second columnar membrane 5 forms a fifth space 7. The fourth space 6 and the fifth space 7 are exhaust spaces.

[0037] This invention utilizes a primary separation membrane assembly 110 and a secondary separation membrane assembly 120 to divide the space into a first space 10, a second space 9, a third space 8, a fourth space 6, and a fifth space 7. The first space 10 serves as the air intake space, while the fourth and fifth spaces 6 and 7 serve as the exhaust spaces. Four flow paths can be formed from the air intake space to the exhaust space: sequentially from the first space 10, the second space 9 to the fourth space 6, sequentially from the first space 10, the second space 9 to the fifth space 7, sequentially from the first space 10, the third space 8 to the fourth space 6, and sequentially from the first space 10, the third space 8 to the fifth space 7. Under the action of the primary separation membrane assembly 110 and the secondary separation membrane assembly 120, multiple flow paths can be used to flow different gas components, ultimately enabling the separation of the gas to be separated (e.g., CO2).

[0038] In one embodiment, the membrane separation device of the present invention is installed after the pollutant emission control system 23 installed in the exhaust pipe 1 of the engine 26. The main emissions at this time are: N2, O2, H2O, and CO2. Table 1 shows the physical properties of CO2, etc., and Table 2 shows the molecular diameter of CO2, etc. Tables 1 and 2 show that the physicochemical properties of these emissions exhibit significant differences in properties such as molecular dynamics diameter. Let the molecular dynamics diameter be denoted by d... N2 d O2 d H2O dCO2 It means that there is d H2O <d CO2 <d N2 <d O2 H2O is a polar molecule, while N2, O2, and CO2 are nonpolar molecules. Due to the presence of a triple bond (N≡N) in the N2 molecule, it is the most stable known diatomic molecule. The CO2 molecule has empty orbitals at lower energy levels and a higher electron affinity, making it relatively more likely to accept electrons. Based on this, a separation membrane with corresponding functions can be designed. Utilizing the proposed tandem two-stage separation membrane structure for CO2 separation in engine 26 emissions, CO2 can be separated from N2, O2, H2O, and CO2 in the exhaust pipe 1.

[0039] Table 1 Physical properties of CO2, etc.

[0040]

[0041]

[0042] Table 2. Molecular diameter of CO2 /

[0043] He <![CDATA[H2]]> <![CDATA[CO2]]> <![CDATA[O2]]> <![CDATA[N2]]> <![CDATA[CH4]]> <![CDATA[C2H4]]> <![CDATA[C3H6]]> Dynamic diameter 2.60 2.89 3.30 3.46 3.64 3.80 3.9 4.5 Collision diameter 2.58 2.92 4.00 3.43 2.68 3.82 4.42 5.06 Effective diameter 2.59 2.90 3.63 3.44 3.66 3.81 / /

[0044] In one embodiment, the radially inner surface of the first cylindrical membrane 2 is modified to a hydrophilic H2O surface layer, i.e., a first hydrophilic layer 22, and the radially outer surface is modified to a hydrophobic H2O surface layer, i.e., a first hydrophobic layer 21. The axially inner surface of the first cylindrical membrane 3 is modified to a hydrophobic H2O surface layer, i.e., a second hydrophobic layer 31, and the axially outer surface is modified to a CO2-loving surface layer, i.e., a first carbon dioxide-loving layer 32. The axially inner surface of the second cylindrical membrane 4 is modified to a hydrophilic H2O surface layer, i.e., a second hydrophilic layer 41. The axially inner surface of the second cylindrical membrane 5 is modified to a CO2-loving surface layer, i.e., a second carbon dioxide-loving layer 51, and the radially inner surface is modified to a CO2-loving surface layer, i.e., a third carbon dioxide-loving layer 52.

[0045] In one embodiment, the radially inner surface of the first cylindrical membrane 2 is made of modified nano-silica, and the radially outer surface is made of modified graphite nanomaterials. The axially inner surface of the first cylindrical membrane 3 is made of modified graphite nanomaterials, and the axially outer surface is made of modified graphene nanomaterials. The axially inner surface of the second cylindrical membrane 4 is made of modified nano-silica. The axially inner surface of the second cylindrical membrane 5 is made of modified graphene nanomaterials, and the radially inner surface is made of modified graphene nanomaterials.

[0046] In one embodiment, the primary separation membrane assembly 110 and the secondary separation membrane assembly 120 have the following characteristics:

[0047] Primary separation membrane module 110: The first cylindrical membrane 2 uses a microporous membrane that follows the molecular sieving mechanism. Its main function is to separate CO2 from N2, O2, and H2O, according to d O2 Size selection of molecular sieve material ZSM-5 The molecular sieve membrane produced has a pore size measured in d. a This indicates that the radially inner surface is modified into a H2O-friendly surface layer using nano-silica, and the radially outer surface is modified into a H2O-repellent surface layer using graphite nanomaterials. The surface modification process is completed using an impregnation method, and the following applies: d H2O <d CO2 <d N2 <d O2 <d a The first columnar membrane 3 is a microporous membrane that follows the molecular sieving mechanism and also functions as an adsorption membrane. Its main function is to separate CO2 and H2O, while N2 and O2 are blocked by the membrane. According to d... CO2 The size was selected from LTA-type zeolite processed with Na + Molecular sieve membranes made from exchanged type A molecular sieve material (commercially known as Na-A type). The aperture size is represented by d b This indicates that the inner axial surface is modified with graphite nanomaterials to form a H₂O-repellent surface layer, while the outer axial surface is modified with graphene nanomaterials to form a CO₂-receptive surface layer. The surface modification process is completed using an impregnation method, resulting in the following on the film surface: d H2O <d CO2 <d b <d N2 <d O2 .

[0048] Secondary separation membrane module 120: The second cylindrical membrane 4 is a microporous membrane that follows the molecular sieving mechanism. Its main function is to separate CO2 and H2O, and radially separate N2, O2, and H2O. ZSM-5 molecular sieve material is selected. The molecular sieve membrane produced has a pore size measured in d. c It means that there is: d H2O <d CO2 <d N2 <d O2 <d c The axial inner surface is modified into a H2O-friendly surface layer using nano-silica. The modification process is completed using an impregnation method. In the H2O-friendly surface layer, d... H2O <d CO2 <d c <d N2 <d O2The second columnar membrane 5 is a microporous membrane that follows the molecular sieving mechanism and also functions as an adsorption membrane. Its main function is to separate CO2 and H2O, according to d... CO2 The size was selected from LTA-type zeolite processed with Na + Molecular sieve membranes made from exchanged type A molecular sieve material (commercially known as Na-A type). The aperture size is represented by d d This indicates that the axial inner surface is modified with graphene nanomaterials to form a CO2-loving surface layer, and the radial side surface is also modified with graphene nanomaterials to form a CO2-loving surface layer. The modification process of the membrane surface is completed by an impregnation method, and the membrane surface has: d H2O <d CO2 <d d <d N2 <d O2 .

[0049] In one embodiment, the inner diameter of the first cylindrical membrane 2, the outer diameter of the first cylindrical membrane 3, and the outer diameter of the second cylindrical membrane 4 are equal. The first cylindrical membrane 3 is embedded in the first cylindrical membrane 2 from one end, flush with the end face of the exhaust space. This facilitates the connection of the first cylindrical membrane 3 and the second cylindrical membrane 5 with the exhaust pipe 1, and enables the formation of the first space 10.

[0050] In one embodiment, the end faces of the second cylindrical membrane 4 and the second cylindrical membrane 5 are flush, and the axial length of the second cylindrical membrane 4 and the axial length of the second cylindrical membrane 5 are equal. This facilitates the division of the fourth space 6 and the fifth space 7 on the outer side of the axis.

[0051] The dimensions of the first cylindrical membrane 2 are: inner diameter r1, radial wall thickness δ1, and axial height δ2. The dimensions of the first cylindrical membrane 3 are: diameter r1 and axial height δ3. The dimensions of the second cylindrical membrane 4 are: outer diameter r1, inner diameter r3, and axial height δ4. The dimensions of the second cylindrical membrane 5 are: axial height δ4 and diameter r3. Each dimension can be designed and adjusted according to actual requirements.

[0052] In one embodiment, the system includes a main housing, comprising an outer housing 18 and an inner housing 19 nested together. The diameter of the outer housing 18 is denoted by r2, and the diameter of the inner housing 19 is approximately equal to r1. The inner diameter side of the inner housing 19 forms a third space 8, which is a cylindrical space. The space between the inner wall of the outer housing 18 and the outer wall of the inner housing 19 forms a second space 9, which is an annular space. The inlet end of the outer housing 18 is provided with a first space 10, which is a cylindrical space. The outlet end of the outer housing 18 is provided with a fourth space 6 and a fifth space 7, where the fourth space 6 is an annular space and the fifth space 7 is a cylindrical space.

[0053] In one embodiment, the system also includes an outlet pipe, which includes an inner pipe 25 and an outer pipe 24 that are nested together. The inner diameter side of the inner pipe 25 is a fifth space 7, and the space between the inner wall of the outer pipe 24 and the outer wall of the inner pipe 25 is a fourth space 6.

[0054] In one embodiment, the system further includes a first pressure sensor 11, a second pressure sensor 12, a third pressure sensor 13, a fourth pressure sensor 14, and a fifth pressure sensor 15. The first pressure sensor 11 is located in the first space 10, the second pressure sensor 12 is located in the second space 9, the third pressure sensor 13 is located in the third space 8, the fourth pressure sensor 14 is located in the fourth space 6, and the fifth pressure sensor 15 is located in the fifth space 7. By placing each pressure sensor in its respective space, the system monitors the pressure state of each space, using P1, P2, P3, P4, and P5 to represent the pressure magnitude of each space. This pressure is then fed back to the ECU (electronic control unit, vehicle computer, i.e., computer control module) of the engine 26 to monitor the pressure conditions on both sides of the membrane during operation, ensuring that the primary separation membrane assembly 110 and the secondary separation membrane assembly 120 operate under appropriate pressure conditions. Due to the successful separation of N2, O2, H2O, and CO2 by the membrane, the order is: P1>P2>P3>P4>P5.

[0055] In one embodiment, a first temperature sensor 16 and a second temperature sensor 17 are also included. The first temperature sensor 16 is disposed in the first space 10, and the second temperature sensor 17 is disposed in the fourth space 6 and / or the fifth space 7. The membrane operates within a certain temperature range. Excessive temperature can damage the membrane material structure. The first temperature sensor 16 and the second temperature sensor 17 are respectively provided at the inlet and outlet of the membrane separation device to monitor the temperatures T1 and T2 at the inlet of the primary separation membrane assembly 110 and the outlet of the secondary separation membrane assembly 120, and feed them back to the ECU of the engine 26 to monitor the temperature status of the membrane during operation and ensure that the primary separation membrane assembly 110 and the secondary separation membrane assembly 120 operate in a suitable temperature environment.

[0056] The working principle of the membrane separation device of the present invention is as follows:

[0057] like Figure 7 As shown, the molecular weights of N2, O2, H2O, and CO2 are expressed as m. N2 m O2 m H2O m CO2 The axial and radial velocity components after the pollutant emission control system 23 of engine 26 are respectively represented by v d v r The pressure is represented by P, and the axial momentum and radial momentum components are represented by M, respectively. d Mr The forces and resistances acting on the membrane surface are represented by F and f, respectively. Therefore: (1) v d >v r (2) From the definition of momentum M=(1 / 2)mv 2 M d >M r .

[0058] The working process of the primary separation membrane module 110:

[0059] (1) Due to v d >v r Therefore, CO2, N2, O2, and H2O primarily react with the first cylindrical membrane 3. (Due to d...) H2O <d CO2 <d b <d N2 <d O2 Since N2 and O2 are blocked by the membrane, the interaction between CO2 and H2O and the first cylindrical membrane 3 is mainly due to the hydrophobicity of the inner axial surface. The force F exerted by water on the surface is... H2O The force (resistance) exerted by the surface on the water f H2O There is: F H2O <f H2O Therefore, although d H2O <d b For the regions 10 and 8 on either side of the membrane, P1 > P3, but H2O will be completely or mostly blocked; let M be the axial momentum of the H2O molecule. dH2O Because of v d Larger, M dH2O It is also relatively large, making F H2O >f H2O Therefore, some H2O passes through the separation membrane and enters the third space 8 from the first space 10. Meanwhile, CO2 molecules do not have f on the membrane surface. CO2 The effect of d, and d CO2 <d b P1>P3, M dCO2 The surface of the first cylindrical membrane 3 is relatively large, and the outer axial surface is a CO2-friendly surface layer. Graphene nanomaterials are also easily heated. Therefore, CO2 will mainly separate from the first cylindrical membrane 3 and enter the third space 8 from the first space 10.

[0060] (2) Due to the influence of the first cylindrical membrane 3, near the surface of the first cylindrical membrane 3, there is a v for N2, O2, and some CO2 and H2O. d <v r For the first cylindrical membrane 2, in the first space 10 and the second space 9 on both sides of the membrane, P1>P2. The relationship between the molecular dynamics diameter and the membrane pore size is: d H2O <dCO2 <d N2 <d O2 <d a This allows all N2, O2, and some H2O and CO2 to pass through the separation membrane and enter the second space 9 from the first space 10. However, due to the affinity of the inner radial surface of the first cylindrical membrane 2 for H2O and the repulsion of the outer radial surface for H2O, H2O molecules are adsorbed onto the inner radial surface of the first cylindrical membrane 2 by an adsorption force f. H2O The H2O molecules are more easily introduced into the membrane pores due to the repulsive force f on the radially outer surface of the first cylindrical membrane 2. H2O The effect of this makes it easier to separate from the surface of the membrane.

[0061] The working process of the secondary separation membrane module 120:

[0062] (1) In the third space 8, CO2 is the main component, with a small amount of H2O also present. CO2 mainly interacts with the second cylindrical membrane 5. For the third space 8 and the fifth space 7 on both sides of the second cylindrical membrane 5, P3>P5. Due to the CO2-friendly surface layer of the second cylindrical membrane 5, CO2 is adsorbed at a certain force f. CO2 The graphene nanomaterials facilitate the entry of CO2 into the membrane pores, and their ease of heating allows CO2 to move from the third space 8 into the fifth space 7, thus completing CO2 separation. A small amount of H2O is adsorbed onto the radially inner surface of the second cylindrical membrane 4 due to the H2O affinity of the inner surface. H2O The effect of this makes it easier to enter the membrane pores. For the third space 8 and the fourth space 6 on both sides of the second cylindrical membrane 4, P3>P4. Therefore, H2O will separate from the third space 8 and enter the fourth space 6.

[0063] (2) In the second space 9, N2, O2, and H2O are mainly present, and a small amount of CO2 is also included. For the second cylindrical membrane 4, d H2O <d CO2 <d N2 <d O2 <d c Since P2 > P4, N2, O2, and H2O can be separated from the second space 9 and transferred into the fourth space 6; while CO2, due to the CO2-friendly surface layer of the second cylindrical membrane 5, is adsorbed by a force f CO2 The graphene nanomaterials are more easily heated, allowing CO2 to enter the membrane pores from the second space 9 and enter the fifth space 7, thus completing the separation of CO2.

[0064] In summary, after the operation of the primary separation membrane module 110 and the secondary separation membrane module 120, N2 and O2 are separated out through the first space 10, the second space 9, and the fourth space 6; H2O is mainly separated out through the first space 10, the second space 9, and the fourth space 6, with a small portion separated out through the first space 10, the third space 8, and the fourth space 6; while CO2 is mainly separated out through the first space 10, the third space 8, and the fifth space 7, with a small portion separated out through the first space 10, the second space 9, and the fifth space 7.

[0065] Refer again Figures 1 to 7 As shown, the present invention provides an engine exhaust device, including an exhaust pipe 1 for connection to an engine 26 and a membrane separation device as described above. The membrane separation device adopts a two-stage separation membrane structure in series (a primary separation membrane assembly 110 and a secondary separation membrane assembly 120). A first space 10 is connected to the exhaust pipe 1, and a pollutant emission control system 23, such as a three-way catalytic converter, can be installed between the first space 10 and the exhaust pipe 1. The device is composed of the exhaust pipe 1, the primary separation membrane assembly 110, and the secondary separation membrane assembly 120, and is divided into five regions with different pressures: a first space 10, a second space 9, a third space 8, a fourth space 6, and a fifth space 7, forming separation routes for N2, O2, H2O, and CO2. After separation by the primary separation membrane assembly 110 and the secondary separation membrane assembly 120, the emitted CO2 gas can be collected in the fifth space 7.

[0066] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A membrane separation device, characterized in that, include: A primary separation membrane assembly includes a first cylindrical membrane and a first columnar membrane. The first columnar membrane is disposed on the inner diameter side of the first cylindrical membrane and near its end. The inner diameter side of the first cylindrical membrane and the axial inner side of the first columnar membrane form a first space, which is an air inlet space. The axial outer side of the first columnar membrane forms a third space, and the outer diameter side of the first cylindrical membrane forms a second space. And a secondary separation membrane assembly, the secondary separation membrane assembly including a second cylindrical membrane and a second columnar membrane, the second columnar membrane being disposed on the inner diameter side of the second cylindrical membrane, the axial inner side of the second cylindrical membrane and the axial inner side of the second columnar membrane being the third space, the outer diameter side of the second cylindrical membrane being the second space, the axial outer side of the second cylindrical membrane being the fourth space, the axial outer side of the second columnar membrane being the fifth space, the fourth space and the fifth space being exhaust spaces; The radially inner surface of the first cylindrical membrane is modified to have an H2O-friendly surface layer, and the radially outer surface is modified to have an H2O-repellent surface layer; the axially inner surface of the first cylindrical membrane is modified to have an H2O-repellent surface layer, and the axially outer surface is modified to have a CO2-friendly surface layer; the axially inner surface of the second cylindrical membrane is modified to have an H2O-friendly surface layer; the axially inner surface of the second cylindrical membrane is modified to have a CO2-friendly surface layer, and the radially inner surface is modified to have a CO2-friendly surface layer. The radial inner surface of the first cylindrical membrane is made of modified nano-silica, and the radial outer surface is made of modified graphite nanomaterial; the axial inner surface of the first cylindrical membrane is made of modified graphite nanomaterial, and the axial outer surface is made of modified graphene nanomaterial; the axial inner surface of the second cylindrical membrane is made of modified nano-silica; the axial inner surface of the second cylindrical membrane is made of modified graphene nanomaterial, and the radial side surface is made of modified graphene nanomaterial.

2. The membrane separation device according to claim 1, characterized in that: The inner diameter of the first cylindrical membrane, the outer diameter of the first cylindrical membrane, and the outer diameter of the second cylindrical membrane are equal.

3. The membrane separation device according to claim 1, characterized in that: The end faces of the second cylindrical membrane and the second columnar membrane are flush, and the axial length of the second cylindrical membrane and the axial length of the second columnar membrane are equal.

4. The membrane separation device according to claim 1, characterized in that: The system includes a main housing, which comprises an outer housing and an inner housing nested together. The inner diameter side of the inner housing is the third space, and the space between the inner wall of the outer housing and the outer wall of the inner housing is the second space. The inlet end of the outer housing is provided with the first space, and the outlet end of the outer housing is provided with the fourth space and the fifth space.

5. The membrane separation device according to claim 3, characterized in that: It also includes an outlet pipe, which comprises an inner pipe and an outer pipe nested together. The inner diameter side of the inner pipe is the fifth space, and the space between the inner wall of the outer pipe and the outer wall of the inner pipe is the fourth space.

6. The membrane separation device according to claim 1, characterized in that: It also includes a first pressure sensor, a second pressure sensor, a third pressure sensor, a fourth pressure sensor, and a fifth pressure sensor. The first pressure sensor is disposed in the first space, the second pressure sensor is disposed in the second space, the third pressure sensor is disposed in the third space, the fourth pressure sensor is disposed in the fourth space, and the fifth pressure sensor is disposed in the fifth space.

7. The membrane separation device according to claim 1, characterized in that: It also includes a first temperature sensor and a second temperature sensor, the first temperature sensor being disposed in the first space, and the second temperature sensor being disposed in the fourth space and / or the fifth space.

8. An engine exhaust device, characterized in that: Includes an exhaust pipe for connection to an engine and a membrane separation device as described in any one of claims 1-7, wherein the first space communicates with the exhaust pipe.

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