Metal organic polyhedral mixed matrix membrane as well as preparation method and application thereof

Abstract

The invention relates to the technical field of carbon capture, in particular to a metal organic polyhedral mixed matrix membrane as well as a preparation method and application thereof. The invention provides a metal organic polyhedral mixed matrix membrane. The metal organic polyhedral mixed matrix membrane comprises a supporting layer; a selective layer formed on the support layer; the selective layer is prepared from raw materials including a high-polarity rubber polymer and a soluble metal organic polyhedron; the high-polarity rubber polymer has a structure as shown in a formula I; the weight-average molecular weight of the formula I is 5-100,000; the soluble metal organic polyhedrons (MOPs) have a structure as shown in a formula II. According to the invention, high CO2 permeability, high CO2 / N2 selectivity and high CO2 / O2 selectivity can be realized. The metal organic polyhedral mixed matrix membrane provided by the invention has better capability of capturing CO2 molecules than the current leading membrane, and the membrane process can be implemented in a coal-fired power plant flue gas carbon dioxide capturing project.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon capture, and in particular to a metal-organic polyhedron mixed matrix membrane, a preparation method and application thereof. Background Art

[0002] Carbon capture and storage technology is widely recognized as an important means of reducing CO2 emissions. Chemical absorption is a relatively mature technology among existing carbon dioxide capture technologies, but it suffers from issues such as high desorption energy consumption, easy absorbent degradation, and equipment corrosion. Membrane separation, a new generation of gas separation technology developed in the 1970s, primarily utilizes pressure differences and differences in gas permeability for separation. This method offers numerous advantages, including low energy consumption, simple equipment, easy operation, and reliable operation. It is considered an important alternative to chemical absorption for capturing CO2 from flue gas in coal-fired power plants and has excellent application prospects.

[0003] At present, membrane separation methods are mainly divided into inorganic membranes and organic membranes according to the material classification of the membrane. Inorganic membrane materials are mainly ceramics, metals, molecular sieves, etc., which have poor mechanical properties and are not easy to apply industrially; organic membrane materials are mainly membranes prepared from organic polymers. Polymer membranes generally have a balance problem in application, that is, membranes with good permeability often have low selectivity and are prone to aging. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a metal-organic polyhedron mixed matrix membrane, its preparation method and application. The metal-organic polyhedron mixed matrix membrane provided by the present invention can effectively break through the balance problem, and can also efficiently capture CO2 with good selectivity at a higher permeability, and can achieve high CO2 permeability, high CO2 / N2 selectivity and high CO2 / O2 selectivity.

[0005] The present invention provides a metal-organic polyhedron mixed matrix membrane, comprising:

[0006] Support layer;

[0007] a selective layer formed on the support layer;

[0008] The selective layer is prepared from raw materials including a highly polar rubber polymer and a soluble metal organic polyhedron;

[0009] The highly polar rubber polymer has a structure shown in Formula I;

[0010]

[0011] The weight average molecular weight of formula I is 50,000 to 100,000;

[0012] The soluble metal-organic polyhedron is a copper-based metal-organic polyhedron.

[0013] Preferably, the preparation method of the highly polar rubber polymer comprises the following steps:

[0014] Under the condition of an initiator, a compound having a structure represented by formula III and a compound having a structure represented by formula IV are polymerized to obtain a highly polar rubber polymer having a structure represented by formula I;

[0015]

[0016] The weight average molecular weight of formula III is 50,000 to 100,000; the weight average molecular weight of formula IV is 50,000 to 100,000;

[0017] The copper-based metal organic polyhedron is Cu 24 (m-BDC) 24 and / or HKUST-1.

[0018] Preferably, the molar ratio of the compound having the structure represented by Formula III to the compound having the structure represented by Formula IV is 0.8-1.2:0.8-1.2.

[0019] Preferably, the initiator is selected from benzoyl peroxide and / or azobisisobutyronitrile;

[0020] The mass ratio of the initiator to the compound having the structure represented by formula III is 0.5-1.5:0.5-1.5;

[0021] The polymerization reaction uses water as a medium.

[0022] Preferably, the polymerization reaction temperature is 60-90° C. and the time is 2-3 hours.

[0023] Preferably, the mass ratio of the high-polarity rubber polymer to the soluble metal organic polyhedron is 1-20:1-20.

[0024] Preferably, the thickness of the selective layer is 200 to 300 nm;

[0025] The thickness of the support layer is 80-120 nm.

[0026] The present invention also provides a method for preparing the metal-organic polyhedron mixed matrix membrane described above, comprising the following steps:

[0027] The high-polarity rubber polymer and the soluble metal organic polyhedron are mixed, stirred at 55-65° C. for 4-8 hours, coated on the surface of the support layer, and dried to obtain a metal organic polyhedron mixed matrix membrane.

[0028] The present invention also provides a use of the metal-organic polyhedron mixed matrix membrane described above, or the metal-organic polyhedron mixed matrix membrane prepared by the preparation method described above, as a CO2 separation membrane.

[0029] The present invention also provides a method for separating CO2, comprising the following steps:

[0030] A) compressing the raw gas to 0.4-0.8 MPa, condensing it to 20-30° C., and then entering a mixer; controlling the gas pressure in the mixer to be 0.3-0.5 MPa;

[0031] B) the gas discharged from the mixer enters a first membrane assembly for CO2 separation; the first membrane assembly uses the metal-organic polyhedron mixed matrix membrane described above, or the metal-organic polyhedron mixed matrix membrane prepared by the preparation method described above;

[0032] C) compressing the permeate gas obtained in step B) to 1-1.5 MPa, condensing it to 20-30° C., and then entering the secondary membrane assembly for CO2 separation. The permeate gas obtained is the product gas, and the retentate gas obtained is compressed and condensed, and then refluxed to the mixer;

[0033] The secondary membrane assembly adopts the metal-organic polyhedron mixed matrix membrane described above, or the metal-organic polyhedron mixed matrix membrane prepared by the preparation method described above.

[0034] The present invention adds a metal-organic framework medium to a polymer membrane to prepare a mixed matrix membrane that can effectively break through the balance problem and can efficiently capture CO2 with good selectivity at a higher permeability. High CO2 permeability, high CO2 / N2 selectivity, and high CO2 / O2 selectivity can be achieved. Specifically, the present invention can achieve high CO2 permeability (3000 gas permeation units [GPU]), high CO2 / N2 selectivity (75), and high CO2 / O2 selectivity (30) at 60°C. The metal-organic polyhedron mixed matrix membrane provided by the present invention has a better ability to capture CO2 molecules than the current leading membranes, and the membrane process can be implemented in the flue gas carbon dioxide capture project of coal-fired power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A process flow chart for separating CO2 provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] The present invention provides a metal-organic polyhedron mixed matrix membrane, comprising:

[0038] Support layer;

[0039] a selective layer formed on the support layer;

[0040] The selective layer is prepared from raw materials including a highly polar rubber polymer and a soluble metal organic polyhedron;

[0041] The highly polar rubber polymer has a structure shown in Formula I;

[0042]

[0043] The weight average molecular weight of formula I is 50,000 to 100,000;

[0044] The soluble metal-organic polyhedron is a copper-based metal-organic polyhedron.

[0045] In certain embodiments of the present invention, the copper-based metal organic polyhedron is Cu 24 (m-BDC) 24 (a copper-based MOF based on isophthalic acid) and / or HKUST-1 (Cu3(BTC)2, a copper-based MOF). Both are commercially available.

[0046] In certain embodiments of the present invention, the mass ratio of the highly polar rubber polymer to the soluble metal organic polyhedron is 1-20:1-20, such as 8-20:1-3, specifically 10:1, 15:1, 20:1.

[0047] In certain embodiments of the present invention, the method for preparing the highly polar rubber polymer comprises the following steps:

[0048] Under the condition of an initiator, a compound having a structure represented by formula III and a compound having a structure represented by formula IV are polymerized to obtain a highly polar rubber polymer having a structure represented by formula I;

[0049]

[0050] The weight average molecular weight of formula III is 50,000 to 100,000; the weight average molecular weight of formula IV is 50,000 to 100,000.

[0051] The present invention has no particular limitation on the sources of the compound having the structure represented by Formula III (PDXLA) and the compound having the structure represented by Formula IV (PDXLEA), and they can be commonly available on the market.

[0052] The molar ratio of the compound having the structure represented by formula III (PDXLA) to the compound having the structure represented by formula IV (PDXLEA) is 0.8-1.2:0.8-1.2, for example, 1:1.

[0053] The polymerization reaction is a thermally initiated polymerization reaction requiring an initiator selected from benzoyl peroxide (BPO) and / or azobisisobutyronitrile (AIBN). The mass ratio of the initiator to the compound having the structure represented by Formula III is 0.5-1.5:0.5-1.5, for example, 1:1.

[0054] The polymerization reaction uses water as a medium.

[0055] The polymerization reaction temperature is 60-90° C., such as 65° C.; and the polymerization reaction time is 2-3 hours, such as 2.5 hours.

[0056] For example, when AIBN is used, the polymerization reaction temperature is usually controlled at 60-70°C; and when BPO is used, the polymerization reaction temperature is usually controlled at 70-90°C.

[0057] In the present invention, the highly polar rubber polymer having the structure shown in Formula I has CO2 affinity and N2 repellency. The soluble metal organic polyhedrons (MOPs) having the structure shown in Formula II are discrete nanocages that are soluble in organic solutions and have strong CO2 affinity.

[0058] In some embodiments of the present invention, the thickness of the selective layer is 200-300 nm, such as 250 nm.

[0059] In certain embodiments of the present invention, the support layer is a thin film composite material (TFC membrane) having a thickness of 80 to 120 nm, such as 100 nm.

[0060] In certain embodiments of the present invention, the metal-organic polyhedron mixed matrix membrane has a maximum transmembrane pressure of 10 bar and an operating time without significant degradation of 200 hours.

[0061] The present invention also provides a method for preparing the metal-organic polyhedron mixed matrix membrane described above, comprising the following steps:

[0062] After mixing high-polarity rubber polymer and soluble metal organic polyhedron, stirring at 55-65° C. for 4-8 hours, coating on the surface of the support layer, and drying, a metal organic polyhedron mixed matrix membrane is obtained.

[0063] In certain embodiments of the present invention, the stirring temperature is 60° C. and the stirring time is 6 hours.

[0064] The present invention also provides a use of the metal-organic polyhedron mixed matrix membrane described above, or the metal-organic polyhedron mixed matrix membrane prepared by the preparation method described above, as a CO2 separation membrane.

[0065] The present invention also provides a method for separating CO2 using the metal-organic polyhedron mixed matrix membrane described above, or the metal-organic polyhedron mixed matrix membrane prepared by the preparation method described above, comprising the following steps:

[0066] A) compressing the raw gas to 0.4-0.8 MPa, condensing it to 20-30° C., and then entering a mixer; controlling the gas pressure in the mixer to be 0.3-0.5 MPa;

[0067] B) the gas discharged from the mixer enters a first membrane assembly for CO2 separation; the first membrane assembly uses the metal-organic polyhedron mixed matrix membrane described above, or the metal-organic polyhedron mixed matrix membrane prepared by the preparation method described above;

[0068] C) compressing the permeate gas obtained in step B) to 1-1.5 MPa, condensing it to 20-30° C., and then entering the secondary membrane assembly for CO2 separation. The permeate gas obtained is the product gas, and the retentate gas obtained is compressed and condensed, and then refluxed to the mixer;

[0069] The secondary membrane assembly adopts the metal-organic polyhedron mixed matrix membrane described above, or the metal-organic polyhedron mixed matrix membrane prepared by the preparation method described above.

[0070] Figure 1 A process flow chart for separating CO2 provided for one embodiment of the present invention; wherein 1 is compressor No. 1, 2 is condenser No. 1, 3 is a mixer, 4 is a primary membrane assembly, 5 is compressor No. 2, 6 is condenser No. 2, 7 is a secondary membrane assembly, 8 is compressor No. 3, and 9 is condenser No. 3.

[0071] In step A):

[0072] The raw gas is flue gas.

[0073] The compression is performed in compressor No. 1. The condensation is performed in condenser No. 1.

[0074] In step B):

[0075] The retentate gas obtained in step B) is discharged.

[0076] In step C):

[0077] The permeate gas obtained in step B) is compressed in compressor No. 2 and condensed in condenser No. 2.

[0078] The obtained retentate gas is compressed in compressor No. 3 and condensed in condenser No. 3.

[0079] The feed gas and the reflux gas are mixed at equal pressure in a mixer.

[0080] To further illustrate the present invention, a metal-organic polyhedron mixed matrix membrane, its preparation method and application provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of protection of the present invention.

[0081] In the embodiment:

[0082] The weight average molecular weight of the compound represented by formula III is 50,000 to 100,000; the weight average molecular weight of the compound represented by formula IV is 50,000 to 100,000.

[0083] Example 1

[0084] Preparation method of high polar rubber polymer:

[0085] In the presence of an initiator BPO, a compound having a structure represented by Formula III and a compound having a structure represented by Formula IV are polymerized in a molar ratio of 1:1 in water at 65° C. for 2.5 hours to obtain a high-polarity rubber polymer having a structure represented by Formula I; the mass ratio of the initiator to the compound having a structure represented by Formula III is 1:1.

[0086] Preparation of metal-organic polyhedron mixed matrix membranes:

[0087] 10 g of a highly polar rubber polymer and 1 g of a soluble metal-organic polyhedron were mixed, stirred at 60°C for 6 h, and then coated on the surface of the support layer. After drying, a selective layer was obtained, thereby obtaining a metal-organic polyhedron mixed matrix membrane.

[0088] The metal-organic polyhedron mixed matrix membrane comprises:

[0089] Support layer; the thickness of the support layer is 100 nm;

[0090] A selective layer is formed on the supporting layer; the thickness of the selective layer is 250 nm.

[0091] Example 2

[0092] The difference from Example 1 is:

[0093] Preparation of metal-organic polyhedron mixed matrix membranes:

[0094] 15g of highly polar rubber polymer and 1g of soluble metal-organic polyhedron were mixed, stirred at 60°C for 6h, and then coated on the surface of the support layer. After drying, a selective layer was obtained, thereby obtaining a metal-organic polyhedron mixed matrix membrane;

[0095] The metal-organic polyhedron mixed matrix membrane comprises:

[0096] Support layer; the thickness of the support layer is 100 nm;

[0097] A selective layer is formed on the supporting layer; the thickness of the selective layer is 250 nm.

[0098] Example 3

[0099] The difference from Example 1 is:

[0100] Preparation of metal-organic polyhedron mixed matrix membranes:

[0101] 20 g of a highly polar rubber polymer and 1 g of a soluble metal-organic polyhedron were mixed, stirred at 60°C for 6 h, and then coated on the surface of the support layer. After drying, a selective layer was obtained, thereby obtaining a metal-organic polyhedron mixed matrix membrane.

[0102] The metal-organic polyhedron mixed matrix membrane comprises:

[0103] Support layer; the thickness of the support layer is 100 nm;

[0104] A selective layer is formed on the supporting layer; the thickness of the selective layer is 250 nm.

[0105] Application Examples 1-3

[0106] according to Figure 1 The method for separating CO2 using the metal-organic polyhedron mixed matrix membrane of Examples 1 to 3 respectively comprises the following steps:

[0107] A) compressing the flue gas (CO2 volume concentration of 10% to 15%, with the remainder being O2 and N2) to 0.4 to 0.5 MPa in compressor No. 1, condensing it to 250°C in condenser No. 1, and then entering the mixer; controlling the gas pressure in the mixer to be 0.4 MPa;

[0108] B) the gas discharged from the mixer enters a first membrane assembly for CO2 separation; the first membrane assembly uses a metal-organic polyhedron mixed matrix membrane; the retentate gas obtained from the first membrane assembly is discharged;

[0109] C) compressing the permeate gas obtained in step B) to 12 MPa in compressor No. 2, condensing it to 25° C. in condenser No. 2, and then entering a secondary membrane assembly for CO2 separation. The permeate gas obtained is the product gas, and the retentate gas obtained is compressed in compressor No. 3, condensed in condenser No. 3, and then refluxed to the mixer;

[0110] The secondary membrane assembly adopts a metal-organic polyhedron mixed matrix membrane.

[0111] Comparative Example 1

[0112] The difference from Application Example 1 is:

[0113] The secondary membrane component adopts traditional polymer membrane polyvinyl alcohol (PVA) membrane, polypropylene membrane or polyvinyl chloride membrane.

[0114] The final CO2 separation effect data of Application Examples 1 to 3 and Comparative Example 1 are shown in Table 1.

[0115] Table 1 Effect data of final separation of CO2 in Application Examples 1 to 3 and Comparative Example 1

[0116]

[0117]

[0118] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A metal-organic polyhedron mixed matrix membrane comprising: Support layer; a selective layer formed on the support layer; The selective layer is prepared from raw materials including a highly polar rubber polymer and a soluble metal organic polyhedron; The highly polar rubber polymer has a structure shown in Formula I; The weight average molecular weight of formula I is 50,000 to 100,000; The soluble metal-organic polyhedron is a copper-based metal-organic polyhedron.

2. The metal-organic polyhedron mixed matrix membrane according to claim 1, wherein The preparation method of the highly polar rubber polymer comprises the following steps: Under the condition of an initiator, a compound having a structure represented by formula III and a compound having a structure represented by formula IV are polymerized to obtain a highly polar rubber polymer having a structure represented by formula I; The weight average molecular weight of formula III is 50,000 to 100,000; the weight average molecular weight of formula IV is 50,000 to 100,000; The copper-based metal organic polyhedron is Cu 24 (m-BDC) 24 and / or HKUST-1.

3. The metal-organic polyhedron mixed matrix membrane according to claim 2, characterized in that The molar ratio of the compound having the structure represented by formula III to the compound having the structure represented by formula IV is 0.8-1.2:0.8-1.

2.

4. The metal-organic polyhedron mixed matrix membrane according to claim 2, characterized in that The initiator is selected from benzoyl peroxide and / or azobisisobutyronitrile; The mass ratio of the initiator to the compound having the structure represented by formula III is 0.5-1.5:0.5-1.5; The polymerization reaction uses water as a medium.

5. The metal-organic polyhedron mixed matrix membrane according to claim 2, characterized in that The polymerization reaction temperature is 60-90° C. and the reaction time is 2-3 hours.

6. The metal-organic polyhedron mixed matrix membrane according to claim 1, wherein: The mass ratio of the high-polarity rubber polymer to the soluble metal organic polyhedron is 1-20:1-20.

7. The metal-organic polyhedron mixed matrix membrane according to claim 1, characterized in that The thickness of the selective layer is 200 to 300 nm; The thickness of the support layer is 80-120 nm.

8. A method for preparing the metal-organic polyhedron mixed matrix membrane according to any one of claims 1 to 7, comprising the following steps: The high-polarity rubber polymer and the soluble metal organic polyhedron are mixed, stirred at 55-65° C. for 4-8 hours, coated on the surface of the support layer, and dried to obtain a metal organic polyhedron mixed matrix membrane.

9. Use of the metal-organic polyhedron mixed matrix membrane according to any one of claims 1 to 7, or the metal-organic polyhedron mixed matrix membrane prepared by the preparation method according to claim 8 as a CO2 separation membrane.

10. A method for separating CO2, comprising the following steps: A) compressing the raw gas to 0.4-0.8 MPa, condensing it to 20-30° C., and then entering a mixer; controlling the gas pressure in the mixer to be 0.3-0.5 MPa; B) the gas discharged from the mixer enters a first membrane assembly for CO2 separation; the first membrane assembly adopts the metal-organic polyhedron mixed matrix membrane according to any one of claims 1 to 7, or the metal-organic polyhedron mixed matrix membrane prepared by the preparation method according to claim 8; C) compressing the permeate gas obtained in step B) to 1-1.5 MPa, condensing it to 20-30° C., and then entering the secondary membrane assembly for CO2 separation. The permeate gas obtained is the product gas, and the retentate gas obtained is compressed and condensed, and then refluxed to the mixer; The secondary membrane assembly adopts the metal-organic polyhedron mixed matrix membrane according to any one of claims 1 to 7, or the metal-organic polyhedron mixed matrix membrane prepared by the preparation method according to claim 8.

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