Carbon dioxide solid adsorbent as well as preparation method and application thereof

Abstract

The invention provides a carbon dioxide solid adsorbent as well as a preparation method and application thereof. The carbon dioxide solid adsorbent is prepared from the following raw materials in parts by weight: 280 to 320 parts of fly ash, 40 to 60 parts of melamine, 40 to 60 parts of trimethylamine, 25 to 35 parts of cationic polyurethane and 100 to 150 parts of water. The carbon dioxide solid adsorbent disclosed by the invention is high in carbon dioxide adsorption rate, high in adsorption capacity and good in carbon dioxide adsorption effect under the condition of rich water vapor.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide adsorption, and in particular to a carbon dioxide solid adsorbent, a preparation method and an application thereof. Background Art

[0002] The main methods for adsorbing carbon dioxide include: 1) Chemical adsorption: using adsorbents to react chemically with carbon dioxide to achieve adsorption. This method has problems such as large adsorbent usage and difficulty in adsorbent regeneration. 2) Physical adsorption: Based on the physical adsorption of carbon dioxide by the adsorbent, the adsorption and desorption processes of this method are relatively simple, but the adsorption capacity is relatively small; 3) Membrane separation: using specific membrane materials to separate and adsorb carbon dioxide. This method has problems such as poor membrane stability and selectivity, and relatively high processing costs; 4) Low-temperature adsorption: using low-temperature conditions to condense carbon dioxide into liquid or solid, thereby achieving adsorption separation. This method requires a large amount of energy to provide low temperatures, which is not conducive to practical applications.

[0003] In actual applications, it has been found that the presence of water vapor significantly interferes with the adsorption and separation of carbon dioxide. The strong interaction between water molecules and the adsorbent affects the adsorption capacity and separation performance of the adsorbent for carbon dioxide, resulting in unfavorable competitive adsorption between the adsorbent, carbon dioxide, and water vapor. In addition, excessive water will occupy the adsorption centers of the adsorbent, resulting in a decrease in the adsorption capacity of the adsorbent for the target substance. This not only reduces the adsorption rate and stability of the adsorbent, but also significantly reduces the adsorption capacity, thereby reducing the efficiency and effectiveness of the adsorbent in water vapor-rich applications.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a solid carbon dioxide adsorbent and its preparation method and application. The solid adsorbent has a fast adsorption rate for carbon dioxide, a high adsorption capacity, and a good adsorption effect for carbon dioxide under conditions rich in water vapor.

[0006] The invention provides a solid carbon dioxide adsorbent, which is characterized by comprising the following raw materials in parts by weight: 280-320 parts of fly ash, 40-60 parts of melamine, 40-60 parts of trimethylamine, 25-35 parts of cationic polyurethane and 100-150 parts of water.

[0007] In the present invention, the fly ash mainly contains the following components by weight: 48-52% silicon dioxide, 18-22% aluminum oxide, 8-12% iron oxide, and 8-12% calcium oxide. The fly ash has a particle size of 40-80 mesh, which can be controlled within this particle size range by mechanical grinding or other methods.

[0008] The cationic polyurethane can be cationic water-based polyurethane AH-1730, which is purchased from Anda Huatai.

[0009] The present invention also provides a method for preparing a solid carbon dioxide adsorbent, comprising the following steps:

[0010] S1: Mechanical grinding of fly ash;

[0011] S2: stirring and mixing fly ash, melamine, trimethylamine and water to obtain a mixed solution;

[0012] S3: adding cationic polyurethane to the mixed solution, stirring and mixing to obtain a viscous solution;

[0013] S4: The viscous liquid is placed into a mold, which is then placed in an oven for heating and naturally cooled to room temperature to obtain a solid carbon dioxide adsorbent.

[0014] In step S1, fly ash is mechanically ground to 40-80 mesh.

[0015] In step S4, the heating temperature is 160-200° C. and the heating time is 4-8 hours.

[0016] The present invention also provides use of the solid carbon dioxide adsorbent in carbon dioxide adsorption.

[0017] Specifically, carbon dioxide in flue gas from a power plant is adsorbed; wherein the moisture content of the flue gas from the power plant is 20-25%.

[0018] The present invention utilizes fly ash as a porous adsorption carrier, which is cheap and easily available, greatly reducing processing costs. At the same time, compounding melamine and trimethylamine with fly ash not only greatly improves the absorption rate and adsorption capacity of carbon dioxide, but also can inhibit the adverse effects of water vapor on the adsorbent, significantly improving the adsorption efficiency and adsorption effect of the adsorbent in water vapor-rich application scenarios. Cationic polyurethane is used as an adhesive to lock the effective ingredients and further enhance the adsorption capacity of the adsorbent. The physical strength and hardness of the adsorbent are improved through a specific curing and molding method, making the adsorbent less susceptible to damage during the adsorption process, reducing the loss of adsorption raw materials, and improving the adsorption capacity of the adsorbent. DETAILED DESCRIPTION

[0019] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0020] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular also includes the plural. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0021] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. 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.

[0022] The raw materials used in each embodiment are as follows:

[0023] Power plant fly ash: mainly contains the following components by mass: silicon dioxide 50%, aluminum oxide 20%, iron oxide 10%, calcium oxide 10%, and the rest 10%;

[0024] Cationic polyurethane: Cationic water-based polyurethane AH-1730 was purchased from Anda Huatai.

[0025] Example 1

[0026] The solid adsorbent for carbon dioxide of this embodiment includes the following raw materials in parts by weight: 300 parts of fly ash, 50 parts of melamine, 50 parts of trimethylamine, 30 parts of cationic polyurethane and 120 parts of water.

[0027] The carbon dioxide solid adsorbent of this embodiment is prepared as follows:

[0028] S1: Take 300 parts of fly ash from a power plant and grind it mechanically to about 60 mesh.

[0029] S2: 50 parts of melamine powder, 50 parts of trimethylamine powder and 120 parts of water were mixed and stirred uniformly to prepare a mixed solution.

[0030] S3: The fly ash mechanically ground in step S1 is stirred and mixed with the mixed solution in step S2 to obtain a fly ash mixed solution.

[0031] S4: adding 30 parts of cationic polyurethane to the fly ash mixture of step S3, stirring thoroughly to obtain a viscous liquid.

[0032] S5: The viscous liquid of step S4 is quickly filled into a honeycomb mold, placed in an oven and heated at 180° C. for 6 hours, and naturally cooled to room temperature to obtain a solid adsorbent for carbon dioxide.

[0033] Example 2

[0034] The solid adsorbent for carbon dioxide of this embodiment includes the following raw materials in parts by weight: 300 parts of fly ash, 40 parts of melamine, 60 parts of trimethylamine, 35 parts of cationic polyurethane and 120 parts of water.

[0035] The carbon dioxide solid adsorbent of this embodiment is prepared as follows:

[0036] S1: Take 300 parts of fly ash from a power plant and grind it mechanically to about 60 mesh.

[0037] S2: 40 parts of melamine powder, 60 parts of trimethylamine powder and 120 parts of water were mixed and stirred uniformly to prepare a mixed solution.

[0038] S3: The fly ash mechanically ground in step S1 is stirred and mixed with the mixed solution in step S2 to obtain a fly ash mixed solution.

[0039] S4: adding 35 parts of cationic polyurethane to the fly ash mixture of step S3, stirring thoroughly to obtain a viscous liquid.

[0040] S5: The viscous liquid of step S4 is quickly filled into a honeycomb mold, placed in an oven and heated at 160° C. for 8 hours, and naturally cooled to room temperature to obtain a solid adsorbent for carbon dioxide.

[0041] Example 3

[0042] The solid adsorbent for carbon dioxide of this embodiment includes the following raw materials in parts by weight: 300 parts of fly ash, 60 parts of melamine, 40 parts of trimethylamine, 25 parts of cationic polyurethane and 120 parts of water.

[0043] The carbon dioxide solid adsorbent of this embodiment is prepared as follows:

[0044] S1: Take 300 parts of fly ash from a power plant and grind it mechanically to about 60 mesh.

[0045] S2: 60 parts of melamine powder, 40 parts of trimethylamine powder and 120 parts of water were mixed and stirred uniformly to prepare a mixed solution.

[0046] S3: The fly ash mechanically ground in step S1 is stirred and mixed with the mixed solution in step S2 to obtain a fly ash mixed solution.

[0047] S4: adding 25 parts of cationic polyurethane to the fly ash mixture in step S3, stirring thoroughly to obtain a viscous liquid.

[0048] S5: The viscous liquid of step S4 is quickly filled into a honeycomb mold, placed in an oven and heated at 200° C. for 4 hours, and naturally cooled to room temperature to obtain a solid adsorbent for carbon dioxide.

[0049] Comparative Example 1

[0050] The solid carbon dioxide adsorbent of this comparative example includes the following raw materials in parts by weight: 300 parts of fly ash, 100 parts of melamine, 30 parts of cationic polyurethane and 120 parts of water.

[0051] The carbon dioxide solid adsorbent of this embodiment is prepared as follows:

[0052] S1: Take 300 parts of fly ash from a power plant and grind it mechanically to about 60 mesh.

[0053] S2: 100 parts of melamine powder and 120 parts of water were mixed and stirred uniformly to prepare a mixed solution.

[0054] S3: The fly ash mechanically ground in step S1 is stirred and mixed with the mixed solution in step S2 to obtain a fly ash mixed solution.

[0055] S4: adding 30 parts of cationic polyurethane to the fly ash mixture of step S3, stirring thoroughly to obtain a viscous liquid.

[0056] S5: The viscous liquid of step S4 is quickly filled into a honeycomb mold, placed in an oven and heated at 180° C. for 6 hours, and naturally cooled to room temperature to obtain a solid adsorbent for carbon dioxide.

[0057] Comparative Example 2

[0058] The solid adsorbent for carbon dioxide in this comparative example comprises the following raw materials in parts by weight: 300 parts of fly ash, 100 parts of trimethylamine, 30 parts of cationic polyurethane and 120 parts of water.

[0059] The carbon dioxide solid adsorbent of this embodiment is prepared as follows:

[0060] S1: Take 300 parts of fly ash from a power plant and grind it mechanically to about 60 mesh.

[0061] S2: 100 parts of trimethylamine powder and 120 parts of water were mixed and stirred uniformly to prepare a mixed solution.

[0062] S3: The fly ash mechanically ground in step S1 is stirred and mixed with the mixed solution in step S2 to obtain a fly ash mixed solution.

[0063] S4: adding 30 parts of cationic polyurethane to the fly ash mixture of step S3, stirring thoroughly to obtain a viscous liquid.

[0064] S5: The viscous liquid of step S4 is quickly filled into a honeycomb mold, placed in an oven and heated at 180° C. for 6 hours, and naturally cooled to room temperature to obtain a solid adsorbent for carbon dioxide.

[0065] Comparative Example 3

[0066] The process is substantially the same as that of Example 1 except that monoethanolamine (MEA) is used to replace the melamine in Example 1.

[0067] Comparative Example 4

[0068] Except that N-methyldiethanolamine (MDEA) was used to replace the trimethylamine in Example 1, the rest was substantially the same as Example 1.

[0069] Comparative Example 5

[0070] The process is substantially the same as that of Example 1, except that ethylenediamine (EDA) is used to replace the melamine in Example 1 and diisopropanolamine (DIPA) is used to replace the trimethylamine in Example 1.

[0071] Comparative Example 6

[0072] The process is substantially the same as that of Example 1 except that polyvinyl acetate (PVAC) is used to replace the cationic polyurethane in Example 1.

[0073] Comparative Example 7

[0074] Except for using zeolite to replace the fly ash in Example 1, the rest is basically the same as Example 1.

[0075] Test Example 1

[0076] A gas adsorption test was conducted using the carbon dioxide solid adsorbent prepared in Example 1. The gas adsorption test method is as follows:

[0077] The test was conducted in a 30-cubic-meter sealed laboratory equipped with a carbon dioxide sensor and a blower. A solid carbon dioxide adsorbent was filled into the blower inlet and fixed with non-woven fabric to form a 2-cm-thick adsorption layer. Adsorption tests were conducted in the following two application scenarios:

[0078] Application scenario 1: Before the adsorption test, the initial concentration of carbon dioxide in the laboratory is 500ppm, the moisture content is 0.1%, and the air volume is 300m 3 / h.

[0079] Application scenario 2: Before the adsorption test, the initial concentration of carbon dioxide in the laboratory is 500ppm, the moisture content is 20%, and the air volume is 300m 3 / h.

[0080] The carbon dioxide concentrations after adsorption for different times are shown in Table 1.

[0081] Table 1 Carbon dioxide concentration after adsorption for different times

[0082]

[0083]

[0084] Test Example 2

[0085] The carbon dioxide solid adsorbent prepared in each embodiment and control example was used to conduct a gas adsorption test, and the test method was the same as that of Test Example 1.

[0086] Each carbon dioxide solid adsorbent is 300m 3 The carbon dioxide concentration after adsorption for 10 minutes at an air volume of / h is shown in Table 2.

[0087] Table 2 Adsorption results of different carbon dioxide solid adsorbents

[0088]

[0089] Test Example 3

[0090] The maximum carbon dioxide adsorption capacity of the carbon dioxide solid adsorbent prepared in each embodiment and control example was tested, and the test method was as follows:

[0091] The carbon dioxide solid adsorbents prepared in each embodiment and control example were placed in a sealed container. Pure carbon dioxide gas was continuously blown at one end, and a carbon dioxide sensor was set at the outlet of the other end. When the concentration value of the outlet sensor stabilized, the adsorbent reached saturation, and the maximum carbon dioxide adsorption capacity was calculated using the following formula:

[0092] Maximum carbon dioxide adsorption capacity = (weight of adsorbent after adsorption - weight of adsorbent before adsorption) / weight of adsorbent before adsorption.

[0093] The results are shown in Table 3.

[0094] Table 3 Maximum carbon dioxide adsorption capacity of different carbon dioxide solid adsorbents

[0095] Carbon dioxide solid adsorbent Maximum carbon dioxide adsorption capacity (unit: mg / g) Example 1 420 Example 2 423 Example 3 405 Comparative Example 1 397 Comparative Example 2 442 Comparative Example 3 298 Comparative Example 4 306 Comparative Example 5 122 Comparative Example 6 351 Comparative Example 7 322

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A solid adsorbent for carbon dioxide, characterized in that: The invention comprises the following raw materials in parts by weight: 280-320 parts of fly ash, 40-60 parts of melamine, 40-60 parts of trimethylamine, 25-35 parts of cationic polyurethane and 100-150 parts of water.

2. The solid adsorbent for carbon dioxide according to claim 1, characterized in that: Fly ash mainly contains the following components by mass: silicon dioxide 48-52%, aluminum oxide 18-22%, iron oxide 8-12%, and calcium oxide 8-12%.

3. The solid adsorbent for carbon dioxide according to claim 1, characterized in that: The particle size of fly ash is 40-80 mesh.

4. The solid adsorbent for carbon dioxide according to claim 1, characterized in that: The cationic polyurethane is cationic water-based polyurethane AH-1730.

5. The method for preparing the solid adsorbent for carbon dioxide according to any one of claims 1 to 4, characterized in that: The steps include: S1: Mechanical grinding of fly ash; S2: stirring and mixing fly ash, melamine, trimethylamine and water to obtain a mixed solution; S3: adding cationic polyurethane to the mixed solution, stirring and mixing to obtain a viscous solution; S4: The viscous liquid is placed into a mold, which is then placed in an oven for heating and naturally cooled to room temperature to obtain a solid carbon dioxide adsorbent.

6. The preparation method according to claim 5, characterized in that In step S1, fly ash is mechanically ground to 40-80 mesh.

7. The preparation method according to claim 5, characterized in that In step S4, the heating temperature is 160-200° C. and the heating time is 4-8 hours.

8. Use of the solid carbon dioxide adsorbent according to any one of claims 1 to 4 in carbon dioxide adsorption.

9. The use according to claim 8, characterized in that Adsorb carbon dioxide from power plant flue gas.

10. The use according to claim 9, characterized in that The moisture content of power plant flue gas is 20-25%.

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