Preparation method and application of carbon capture material suitable for small-scale biogas power generation

Abstract

The present invention provides a preparation method and application of a carbon capture material suitable for small-scale biogas power generation. The method comprises the following steps: S1 uses anhydrous ethanol and high-purity water to prepare a preparation solvent A of a KAUST-7 organic metal framework; S2 utilizes NiNbOF5 to mix with the solvent A in step S1 to prepare a NiNbOF5 solution; S3 utilizes pyrazine, MEA and the solvent A in step S1 to mix and prepare a pyrazine-MEA solution; S4, according to the ratio of 1gNiNbOF5 solution to 150g molecular sieve, an appropriate amount of large-pore molecular sieve is placed in a reactor, NiNbOF5 solution and pyrazine-MEA solution are added and quickly stirred to form a uniform reaction, and then naturally cooled after the reaction is completed, and washed with high-purity water and anhydrous ethanol in succession and then dried to obtain the carbon capture material. The carbon capture material prepared by the preparation method of the carbon capture material suitable for small-scale biogas power generation is installed in an adsorption device for separating and capturing CO2 in flue gas without external power, and the desorption process can be carried out at a low temperature and can be reused many times.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon capture, and particularly relates to a preparation method of a CO2 capture material suitable for low-flow, intermittent and small-scale biogas power generation without heat source and an application of the material in carbon capture. BACKGROUND

[0002] Under the same heat value condition, the carbon emission of natural gas is about 55% of that of coal, and the proportion of natural gas in the energy structure will gradually increase in the future. Rural areas have natural biomass renewable energy, and the use of biomass energy to produce natural gas can realize the integration of natural gas and renewable energy, which is beneficial to energy security and the development of a good ecological environment. On this basis, the coupling of carbon capture technology in rural small-scale biogas power generation projects can further reduce the carbon emission of the whole link, and the desorption of the carbon-rich gas can also be used for agricultural production, so that the whole system achieves the beneficial effect of zero carbon or even negative carbon.

[0003] However, the capture material used in the traditional carbon capture technology is an amine functionalized adsorbent, which has high selectivity and strong stability for CO2, and the temperature needs to be continuously increased during the desorption process, and the desorption concentration has only one specification of the highest concentration. The small-scale biogas power generation project has the characteristics of low exhaust flow, intermittent operation and no additional heat source during operation, and the carbon-rich gas used for agricultural production does not require high-concentration CO2. Obviously, the traditional carbon capture material and device cannot adapt to the CO2 resource utilization in the current agricultural scene, and therefore further improvement is needed. SUMMARY

[0004] The purpose of the present application is to provide a preparation method of a carbon capture material suitable for small-scale biogas power generation in an agricultural production scene and an application thereof. The carbon capture material prepared by the present application can selectively adsorb CO2 under low flow and without power, the desorption process can be carried out at low temperature, and the material can be reused multiple times.

[0005] In order to achieve the above technical purpose, the present application provides a preparation method of a carbon capture material suitable for small-scale biogas power generation, which specifically comprises the following steps:

[0006] S1, preparing a solvent A of KAUST-7 organic metal framework by using anhydrous ethanol and high-purity water, wherein the mass ratio of anhydrous ethanol to high-purity water in the solvent A is 3.5-4.0:1-1.2;

[0007] S2, mixing NiNbOF5 with the solvent A in step S1 to prepare a NiNbOF5 solution, and performing ultrasonic dispersion treatment at room temperature until the solution is clear and transparent; the mass ratio of NiNbOF5 to the solvent A in the NiNbOF5 solution is 7-7.5:10-11.5;

[0008] S3, a pyrazine-MEA solution is prepared by mixing pyrazine, MEA (ethanolamine) and solvent A in the S1 step, and ultrasonic dispersion treatment is performed at room temperature until it is clear and transparent; in the pyrazine-MEA solution, the mass ratio of pyrazine, MEA and solvent A is 1.5-2.0:1.8-2.5:10-15;

[0009] S4, according to the proportion of 1g NiNbOF5 solution matching 150g molecular sieve, a proper amount of large-pore molecular sieve is put into a reaction kettle, and after adding NiNbOF5 solution and pyrazine-MEA solution, it is quickly stirred uniformly, and then it is reacted at 110-125℃ for 24 hours, and then it is naturally cooled to room temperature to obtain a molecular sieve attached with KAUST-7 organic metal framework; wherein the pore size of the large-pore molecular sieve is 100-150nm, and the mass ratio of the NiNbOF5 solution to the pyrazine-MEA solution is 1-1.2:40-65;

[0010] S5, the molecular sieve attached with KAUST-7 organic metal framework prepared in step S4 is washed with high-purity water and anhydrous ethanol in sequence, and then it is dried in an oven at 80-90℃ to obtain the carbon capture material.

[0011] The further technical solution of the present application is that the NiNbOF5 in the S2 step is prepared by the following method: the reactants are sequentially added and mixed together according to the molar ratio of 1Nb2O5:2NiO:10HF, continuously stirred at room temperature for 2-4h, then transferred to a reaction kettle, kept at 100-120℃ for 24h, cooled to 25-28℃ by cold water, opened the reaction kettle and poured into an evaporating dish, and evaporated at 60-70℃ to obtain green NiNbOF5 crystals; the green NiNbOF5 crystals are prepared into a NiNbOF5 solution with solvent A in the S1 step.

[0012] The preferable technical solution of the present application is that the mass ratio of anhydrous ethanol to high-purity water in the solvent A in the S1 step is 3.8-4.0:1.

[0013] The preferable technical solution of the present application is that in the S3 step, the mass of MEA in the pyrazine-MEA solution is the same as the mass of pyrazine.

[0014] The preferable technical solution of the present application is that in the S4 step, the NiNbOF5 solution and the pyrazine-MEA solution are mixed at 5-10℃, and then put into a reaction kettle containing a proper amount of large-pore molecular sieve; the large-pore molecular sieve is a phosphoaluminate molecular sieve.

[0015] The application further provides an application of the carbon capture material prepared by the method.

[0016] The further technical scheme of the application is that the adsorption equipment comprises a box with a photovoltaic cell and a carbon capture material module installed in the box, the lower part of the box is provided with an air inlet channel, the top of the box is provided with an air outlet channel, and the box is provided with multiple layers of carbon capture material modules from bottom to top; the carbon capture material module comprises an upper and lower open outer shell and a metal mesh partition plate arranged in the middle of the outer shell, PTFE filter membranes are respectively covered on the upper and lower open surfaces of the outer shell, and the metal mesh partition plate in the outer shell is filled with the carbon capture material suitable for small-scale biogas power generation.

[0017] The further technical scheme of the application is that CO2 monitoring instruments are respectively installed on the air inlet channel and the air outlet channel of the box, the CO2 monitoring instruments are signal-connected with an external control device through signal lines, the air inlet channel of the box is communicated with a biogas tail flue gas discharge pipeline of a small-scale biogas power generation device, and the carbon capture material module is heated to 60-85 DEG C during the working process of the adsorption equipment.

[0018] The further technical scheme of the application is that the box is a hollow shell structure with four closed sides, multiple support slide rails are arranged on the two side walls in the box, the box is divided into multiple hollow cavities for drawing and inserting the carbon capture material module through the support slide rails, and cavities are arranged on the front of the box; the carbon capture material module is arranged in a drawer shape, slide tracks matched with the support slide rails are arranged on the two sides of the bottom of the carbon capture material module, and the carbon capture material module is inserted into the corresponding hollow cavity through the cavities on the front of the box; an air inlet cavity communicated with the cavities in the box is arranged at the bottom of the box, the air inlet channel is communicated with the air inlet cavity, and a drying agent is filled in the air inlet cavity; an air outlet cavity communicated with the cavities in the box is arranged at the top of the box, and the air outlet channel is communicated with the air outlet cavity.

[0019] The further technical scheme of the application is that the filter hole diameter of the PTFE filter membrane is 12-15 μm, heating wires are arranged on the metal mesh, and the carbon capture material module is heated to 60-85 DEG C through the heating wires when the carbon capture material module is desorbed.

[0020] In the application, the biogas tail flue gas enters from the air inlet of the box, is discharged from the top channel after passing through the carbon capture module stored in the box, and the CO2 monitoring instruments installed on the inlet and outlet monitor the current CO2 concentration and temperature data in real time; the carbon capture module is in a drawer shape, when the box with multiple layers of the carbon capture module is operated, the biogas tail flue gas enters from the PTFE filter membrane at the bottom of the module and is discharged from the top, so that the capture of CO2 is completed.

[0021] Advantages of the present application:

[0022] (1) After adding a certain amount of ethanol to the preparation solvent of KAUST-7 organic metal framework in the present application, ethanol will be adsorbed on the surface of KAUST-7 crystal as an end-capping agent, forcing the crystallinity and size of the crystal to decrease from the traditional 500 nm to below 200 nm;

[0023] (2) Increasing MEA organic base in the pyrazine solution can promote the increase of the supersaturation of the synthesis solution, and the organic ligand pyrazine is more likely to coordinate with metal ions Ni 2+ , improving the growth rate of KAUST-7 crystal, and easily obtaining ultra-fine crystals below 100 nm;

[0024] (3) The molecular sieve with a pore size of more than 100 nm has more cavities, which can act as nucleation sites to promote the formation of KAUST-7 crystals during the synthesis of KAUST-7, and can weaken the crystal agglomeration phenomenon caused by small crystal size, ultimately enabling KAUST-7 crystals below 100 nm in size to exist stably in the cavities of the molecular sieve, and can selectively adsorb CO2 under low flow and no power as a carbon capture material;

[0025] (4) Washing the carbon capture material with anhydrous ethanol can clean the MEA on it, avoiding the generation of chemical absorption that is not easy to desorb during the carbon capture process, improving the physical absorption efficiency and reducing the release difficulty;

[0026] (5) In the present application, the use of KAUST-7 organic metal framework alone for carbon capture has a high cost (1 kg of market price is 50,000 yuan), while using molecular sieve as a substrate can significantly reduce the material use cost (the cost of large pore size molecular sieve is only 200 yuan / kg), and since the rural carbon capture application scenario does not require high concentration CO2 release, the molecular sieve attached with KAUST-7 is sufficient to meet the demand. BRIEF DESCRIPTION OF DRAWINGS

[0027] Fig. 1 is the overall structure schematic diagram of the adsorption device in the present application;

[0028] Fig. 2 is the structure schematic diagram of the adsorption box in the present application;

[0029] Fig. 3 is the structure schematic diagram of the carbon capture module in the present application.

[0030] In the figure: 1 - box, 100 - support slide rail, 101 - hollow partition, 102 - air inlet cavity, 103 - air outlet cavity, 2 - air inlet channel, 3 - air outlet channel, 4 - carbon capture material module, 400 - outer shell, 401 - metal mesh partition, 402 - PTFE filter membrane, 403 - carbon capture material, 404 - slide, 5 - CO2 monitoring instrument, 6 - control device. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] The NiNbOF5 in the following embodiments is prepared by the following method: the reactants are sequentially added and mixed together according to a molar ratio of 1 Nb2O5:2NiO:10HF, continuously stirred at room temperature for 2-4 h, then transferred to a reaction kettle, kept at 100-120℃ for 24 h, cooled to 25-28℃ with cold water, opened to pour into an evaporating dish, and evaporated at 60-70℃ to obtain green NiNbOF5 crystals.

[0033] The carbon capture material provided in Example 1 is suitable for small-scale biogas power generation in an agricultural production scenario, and its preparation includes the following steps:

[0034] S1, prepare solvent A for KAUST-7 metal-organic framework using anhydrous ethanol and high-purity water, and the mass ratio of anhydrous ethanol to high-purity water in the solvent A is 4:1;

[0035] S2, mix NiNbOF5 with the solvent A in step S1 to prepare a NiNbOF5 solution, and ultrasonic dispersion treatment is performed at room temperature until it is clear and transparent; in the NiNbOF5 solution, the mass ratio of NiNbOF5 to solvent A is 7.5:11;

[0036] S3, prepare a 1:1 pyrazine-MEA solution using the solvent A in step S1, and ultrasonic dispersion treatment is performed at room temperature until it is clear and transparent; in the pyrazine-MEA solution, the mass ratio of pyrazine, MEA (ethanolamine) and S1 solvent is 1:1:5;

[0037] S4, 1 part of the NiNbOF5 solution and 50 parts of the pyrazine-MEA solution were first mixed at 5°C, and then a proper amount of large-pore molecular sieve was put into a reaction kettle and reacted at 120°C for 24 hours, and naturally cooled to room temperature to prepare a molecular sieve attached with KAUST-7 organic metal framework; wherein the pore size of the large-pore molecular sieve ranges from 100 to 150 nm;

[0038] S5, the molecular sieve attached with KAUST-7 organic metal framework was washed with high-purity water and anhydrous ethanol in sequence, and then dried in an oven at 80-90°C to obtain a molecular sieve attached with KAUST-7, i.e. carbon capture material A.

[0039] Example 2 provides a new type of carbon capture material suitable for agricultural production scenarios, which is prepared by the following steps:

[0040] S1, preparing solvent A of KAUST-7 organic metal framework by using anhydrous ethanol and high-purity water, wherein the mass ratio of anhydrous ethanol to high-purity water in the solvent A is 3.8:1;

[0041] S2, preparing NiNbOF5 solution by mixing NiNbOF5 with the solvent A in S1, and treating by ultrasonic wave at room temperature until it is clear and transparent; wherein the mass ratio of NiNbOF5 to the solvent in S1 in the NiNbOF5 solution is 7:11;

[0042] S3, preparing 1:1 pyrazine-MEA solution by using the solvent in S1, and treating by ultrasonic wave at room temperature until it is clear and transparent; wherein the mass ratio of pyrazine, MEA to the solvent in S1 in the pyrazine-MEA solution is 1.8:1.8:15;

[0043] S4, 1 part of the NiNbOF5 solution and 40 parts of the pyrazine-MEA solution were first mixed at 5°C, and then a proper amount of large-pore molecular sieve was put into a reaction kettle and reacted at 120°C for 24 hours, and naturally cooled to room temperature to prepare a molecular sieve attached with KAUST-7 organic metal framework; wherein the pore size of the large-pore molecular sieve ranges from 100 to 150 nm;

[0044] S5, the molecular sieve attached with KAUST-7 organic metal framework was washed with high-purity water and anhydrous ethanol in sequence, and then dried in an oven at 80-90°C to obtain a molecular sieve attached with KAUST-7, i.e. carbon capture material B.

[0045] Example 3 provides a new type of carbon capture material suitable for agricultural production scenarios, which is prepared by the following steps:

[0046] S1, preparation of solvent A of KAUST-7 metal-organic framework using anhydrous ethanol and high-purity water, the mass ratio of anhydrous ethanol and high-purity water in the solvent A is 3.8:1.2;

[0047] S2, preparation of NiNbOF5 solution by mixing NiNbOF5 with solvent A in S1, ultrasonic dispersion treatment at room temperature until clear and transparent; the mass ratio of NiNbOF5 and S1 solvent in the NiNbOF5 solution is 7:10;

[0048] S3, preparation of 1:1 pyrazine-MEA solution by using solvent in S1, ultrasonic dispersion treatment at room temperature until clear and transparent. The mass ratio of pyrazine, MEA and S1 solvent in the pyrazine-MEA solution is 2:2:12;

[0049] S4, first mix 1 part of NiNbOF5 solution and 60 parts of pyrazine-MEA solution at 10°C, then put appropriate amount of large pore molecular sieve into the reaction kettle, react at 120°C for 24 hours, and naturally cool to room temperature to prepare molecular sieve attached with KAUST-7 metal-organic framework; wherein the pore size of the large pore molecular sieve ranges from 100 to 150 nm;

[0050] S5, wash the molecular sieve attached with KAUST-7 metal-organic framework with high-purity water and anhydrous ethanol in sequence, then dry in an oven at 80-90°C to obtain the molecular sieve attached with KAUST-7, i.e. carbon capture material C.

[0051] In example 4, carbon capture materials A, B and C prepared in examples 1, 2 and 3, respectively, are loaded into carbon capture modules and installed into adsorption equipment, connected to a fixed emission source for separation and capture of CO2 in flue gas without external power, and the solid carbon capture materials after adsorption are desorbed and recycled for capture after release.

[0052] In example 4, the adsorption equipment is, for example, Figs. 1 to 3As shown, including the box 1 with photovoltaic cells and installed in the box 1 carbon capture material module, the lower part of the box 1 is provided with air inlet channel 2, the top is provided with air outlet channel 3, the air inlet channel 2 and air outlet channel 3 of the box 1 are respectively installed with CO2 monitoring instrument 5, the CO2 monitoring instrument 5 is connected with the external control device 6, i.e. the upper computer signal connection; The box 1 is provided with multiple layers of carbon capture material module from bottom to top. The carbon capture material module 4 includes an upper and lower open outer shell 400 and a metal mesh partition 401 in the middle of the outer shell, and a PTFE filter membrane 402 is covered on the upper and lower open surfaces of the outer shell, respectively, and the metal mesh partition 401 in the outer shell 400 is filled with carbon capture material 403 suitable for small-scale biogas power generation. The filter hole diameter of the PTFE filter membrane is 12-15 μm, and the metal mesh 401 is provided with heating wire.

[0053] The box 1 in the embodiment is a four-sided closed hollow shell structure, as shown in Fig. 2 The two side walls in the box 1 are provided with multiple layers of support slide rails 100, and the box 1 is divided into multiple hollow cavities 101 for inserting and extracting carbon capture material modules 4 by the support slide rails 100, and the front of the box 1 is provided with a cavity opening; As shown in Fig. 3 The carbon capture material module 4 is set as a drawer, and the two sides of the bottom are provided with slide ways 404 matched with the support slide rails 100, and the carbon capture material module 4 is inserted into the corresponding hollow cavity 101 through the cavity opening in the front of the box 1; The end of the carbon capture material module 4 is provided with a baffle that can seal and shield the hollow cavity 101, and after the carbon capture material module 4 is inserted into the hollow cavity 101, the entire front of the box is shielded and closed by the baffle, so as to avoid the smoke from escaping. The bottom of the box 1 is provided with an air inlet cavity 102 communicating with the box cavity, the air inlet channel 2 communicates with the air inlet cavity 102, and the air inlet cavity 102 is filled with a drying agent, which can absorb the moisture in the smoke; The top of the box 1 is provided with an air outlet cavity 103 communicating with the box cavity, and the air outlet channel 3 communicates with the air outlet cavity 103. The air inlet channel 2 of the box 1 communicates with the biogas tail gas exhaust pipe of the small-scale biogas power generation device, and the carbon capture material module is heated to 60-85℃ during the operation of the adsorption equipment. And when the carbon capture material module is desorbed, the carbon capture material module is heated to 60-85℃ by the heating wire.

[0054] In example 5, the adsorption equipment in example 4 is applied to the rear end of the biogas power generation device of a rural energy revolution technology demonstration project in Hubei Province, and the existing monitoring system is used to record the CO2 capture process data. The steps are as follows:

[0055] S1, the biogas power generation tail flue gas flow rate is 10 m / s, the carbon capture material A, B, C prepared in examples 1, 2, 3 and traditional molecular sieve carbon capture material D, calcium lime carbon capture material E are respectively loaded into the carbon capture module, and installed in the adsorption equipment for testing.

[0056] S2, the biogas generator is controlled to run from 8:00 to 20:00 every day, after 1.2L of each material is put into the box, running for 3 days, the whole box is taken out. During the period, the CO2 content in the inlet and outlet flue gas is monitored.

[0057] S3, the module partition in the box is powered and heated to 60 DEG C, and the CO2 content at the outlet of the module device is investigated.

[0058] S4, the same batch of materials is repeated twice to determine that the new adsorption material still has strong adsorption capacity after being used for many times.

[0059] The adsorption performance test results of the material and device are shown in Table 1 as follows:

[0060] Table 1 CO2 adsorption capacity of different carbon capture materials

[0061]

[0062] From Table 1 above, it can be seen that the carbon capture material prepared in the examples has better carbon capture effect than the traditional molecular sieve, and has basically the same carbon capture effect as calcium lime, and also has cycle stability.

[0063] The release process test results after capture are shown in Table 2 as follows:

[0064] Table 2 desorption release capacity of different carbon capture materials

[0065]

[0066] From Table 2 above, it can be seen that the carbon capture material prepared in the examples has faster desorption release effect than the traditional molecular sieve, and at the same time, due to the strong stability of calcium lime, the desorption release cannot be completed at 60 DEG C, indicating that the carbon capture material prepared in the examples has better low-temperature release capacity than calcium lime.

[0067] Example 6, the carbon capture material A, B, C prepared in examples 1, 2, 3 and traditional molecular sieve carbon capture material D, calcium lime carbon capture material E are respectively loaded into the carbon capture module, and installed in the adsorption equipment in example 4, and applied to the rear end of the rural 10L heating stove, the CO2 concentration at the inlet and outlet of the device is recorded by a portable computer, and the steps are as follows:

[0068] S1, the furnace tail flue gas flow rate is 1 m / s, the above five kinds of carbon capture materials are respectively put into the box for testing.

[0069] S2, control the heating stove to run continuously for 24 hours in winter, take 1.5L of each carbon capture material and put it into the box, run for 7 days, and take out the whole box. During the period, monitor the CO2 content in the inlet and outlet flue gas.

[0070] S3, the module partition in the box is powered and heated to 70℃, and the CO2 content at the outlet of the module device is investigated.

[0071] S4, repeat the test twice for the same batch of materials to determine that the new adsorption material still has strong adsorption capacity after being used for many times.

[0072] The test results of the material and device adsorption performance are shown in Table 1 below:

[0073] Table 1 CO2 adsorption capacity of different carbon capture materials

[0074]

[0075]

[0076] From the above Table 1, under the condition of low flow rate and long time adsorption, the five materials are basically saturated after running for 7 days. The carbon capture material prepared in the embodiment of the present application still has better carbon capture effect, which is the same as that of calcium lime, and also has certain cycle stability.

[0077] The test results of the release process after capture are shown in Table 2 below:

[0078] Table 2 desorption and release capacity of different carbon capture materials

[0079]

[0080] From the above Table 2, the carbon capture material prepared in the embodiment of the present application still has faster desorption and release effect compared with the traditional molecular sieve under the condition of adsorption saturation. Since calcium lime has strong stability, it cannot complete desorption and release at 60℃, which shows that the carbon capture material prepared in the embodiment of the present application has better low-temperature release capacity compared with calcium lime.

[0081] In the description of the specification, the description of the reference terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0082] The above merely provides the illustration and description of the concept of the present application. Those skilled in the art can make various modifications or supplement to the described specific embodiments or adopt similar ways to replace, as long as it does not deviate from the concept of the present application or exceed the scope defined by the present claims, which should belong to the protection scope of the present application.

Claims

1. A method for preparing a carbon capture material suitable for small-scale biogas power generation, characterized in that: The specific steps include: S1. Prepare solvent A for preparing KAUST-7 organic metal framework using anhydrous ethanol and high-purity water, wherein the mass ratio of anhydrous ethanol to high-purity water in solvent A is 3.5-4.0:1-1.2; S2. Prepare a NiNbOF5 solution by mixing NiNbOF5 with the solvent A prepared in step S1, and subjecting the solution to ultrasonic dispersion treatment at room temperature until the solution becomes clear and transparent; wherein the mass ratio of NiNbOF5 to solvent A is 7-7.5:10-11.5; S3, preparing a pyrazine-MEA solution by mixing pyrazine, MEA, and the solvent A prepared in step S1, and subjecting the mixture to ultrasonic dispersion treatment at room temperature until the mixture becomes clear and transparent; wherein the mass ratio of pyrazine, MEA, and solvent A in the pyrazine-MEA solution is 1.5-2.0:1.8-2.5:10-15; S4. According to the ratio of 1g NiNbOF5 solution to 150g molecular sieve, an appropriate amount of large-pore molecular sieve is placed in a reactor, and the NiNbOF5 solution and pyrazine-MEA solution are added and quickly stirred evenly. The mixture is reacted at 110-125°C for 24 hours, and naturally cooled to room temperature to prepare a molecular sieve attached to a KAUST-7 organic metal framework; wherein the pore size range of the large-pore molecular sieve is 100-150nm, and the mass ratio of the NiNbOF5 solution to the pyrazine-MEA solution is 1-1.2:40-65; S5. The molecular sieve attached with the KAUST-7 organic metal framework prepared in step S4 is washed with high-purity water and anhydrous ethanol successively, and then placed in an oven at 80-90° C. to dry to obtain the carbon capture material.

2. The method for preparing a carbon capture material suitable for small-scale biogas power generation according to claim 1, characterized in that: The NiNbOF5 in step S2 is prepared by the following method: reactants are added in sequence according to a molar ratio of 1Nb2O5:2NiO:10HF, and stirred continuously at room temperature for 2 to 4 hours. The reactants are then transferred to a reactor and reacted at 100 to 120°C for 24 hours. The reactants are then cooled to 25 to 28°C with cold water. The reactor is opened and poured into an evaporating dish, and evaporated at 60 to 70°C to obtain green NiNbOF5 crystals. The green NiNbOF5 crystals are then mixed with solvent A in step S1 to prepare a NiNbOF5 solution.

3. The method for preparing a carbon capture material suitable for small-scale biogas power generation according to claim 1 or 2, characterized in that: The mass ratio of anhydrous ethanol to high-purity water in solvent A of step S1 is 3.8-4.0:

1.

4. The method for preparing a carbon capture material suitable for small-scale biogas power generation according to claim 1 or 2, characterized in that: In step S3, in the pyrazine-MEA solution, the mass of MEA is the same as the mass of pyrazine.

5. The method for preparing a carbon capture material suitable for small-scale biogas power generation according to claim 1 or 2, characterized in that: In step S4, the NiNbOF5 solution and the pyrazine-MEA solution are mixed at 5-10° C. and then placed in a reaction kettle containing an appropriate amount of large-pore molecular sieve; the large-pore molecular sieve is a phosphate-aluminate molecular sieve.

6. Use of a carbon capture material prepared by the method according to any one of claims 1 to 5 for small-scale biogas power generation, characterized in that: The carbon capture material prepared by the method for preparing the carbon capture material suitable for small-scale biogas power generation is installed in an adsorption device for separating and capturing CO2 in flue gas without external power.

7. The use of a carbon capture material suitable for small-scale biogas power generation according to claim 6, characterized in that: The adsorption device comprises a box (1) with a photovoltaic cell and a carbon capture material module installed in the box (1); an air inlet channel (2) is provided at the bottom of the box (1), and an air outlet channel (3) is provided at the top; and multiple layers of carbon capture material modules are arranged from bottom to top in the box (1); the carbon capture material module (4) comprises an outer shell (400) with upper and lower openings and a metal mesh partition (401) placed in the middle of the outer shell, the upper and lower open surfaces of the outer shell are respectively covered with PTFE filter membranes (402), and the upper and lower metal mesh partitions (401) in the outer shell (400) are filled with carbon capture materials (403) suitable for small-scale biogas power generation.

8. The use of a carbon capture material suitable for small-scale biogas power generation according to claim 7, characterized in that: A CO2 monitoring instrument (5) is installed on the air inlet channel (2) and the air outlet channel (3) of the box (1), respectively. The CO2 monitoring instrument (5) is connected to an external control device (6) via a signal line; the air inlet channel (2) of the box (1) is connected to a biogas tail flue gas exhaust pipe of a small biogas power generation device, and during the operation of the adsorption device, the carbon capture material module is heated to 60-85°C.

9. The use of a carbon capture material suitable for small-scale biogas power generation according to claim 7, characterized in that: The box (1) is a hollow shell structure closed on four sides, and multiple layers of supporting slide rails (100) are provided on both side walls of the box (1). The supporting slide rails (100) divide the box (1) into multiple hollow compartments (101) for inserting and removing the carbon capture material modules (4), and a cavity opening is provided on the front side of the box (1); the carbon capture material module (4) is arranged in a drawer shape, and two sides of the bottom thereof are provided with corresponding support rails (100). The air inlet (102) is connected to the compartment of the box body and is inserted into the corresponding hollow compartment (101) through the cavity on the front of the box body (1); an air inlet cavity (102) is provided at the bottom of the box body (1), the air inlet channel (2) is connected to the air inlet cavity (102), and the air inlet cavity (102) is filled with a desiccant; an air outlet cavity (103) is provided at the top of the box body (1), the air outlet channel (3) is connected to the air outlet cavity (103).

10. The use of a carbon capture material suitable for small-scale biogas power generation according to claim 7 or 8, characterized in that: The pore diameter of the PTFE filter membrane is 12 to 15 μm. A heating wire is provided on the metal mesh (401), and when the carbon capture material module is desorbed, the heating wire heats the carbon capture material module to 60 to 85° C.

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