Composite amine decarburizer and its application, method for capturing carbon dioxide

Abstract

This invention relates to the field of carbon dioxide capture, and discloses a composite amine decarbonizing agent and its application, as well as a method for capturing carbon dioxide. The decarbonizing agent comprises a primary absorbent, a co-absorbent, a solvent, and an optional antioxidant. Specifically, based on a total mass of 100 wt% of the decarbonizing agent, the primary absorbent comprises 40-60 wt%, the co-absorbent comprises 2-5 wt%, the antioxidant comprises 0-1 wt%, and the solvent comprises 35-58 wt%. The primary absorbent is diethylaminoethanol, and the co-absorbent is piperazine. This decarbonizing agent can maintain a high carbon dioxide absorption rate while improving carbon dioxide absorption efficiency, absorption performance, and regeneration performance.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide capture, specifically to a composite amine decarbonizing agent and its application, and a method for capturing carbon dioxide. Background Technology

[0002] Waste gas emissions are a significant environmental issue in industrial production processes. To reduce emissions of harmful gases such as carbon dioxide, amine liquid decarbonizing agents are widely used in industrial waste gas treatment. Traditional coal-fired power plants, due to their low flue gas pressure and low CO2 concentration, typically employ chemical absorption as their post-combustion capture process. This chemical adsorbent captures CO2 through a chemical reaction, exhibiting good selectivity and absorption rate; however, it requires a large amount of energy to separate the adsorbent from the CO2 and regenerate the adsorbent to obtain pure CO2.

[0003] The main absorbent in traditional processes is ethanolamine (MEA), which has a fast absorption rate but low carbon dioxide absorption capacity. Therefore, it is necessary to improve and optimize the decarbonization agent to enhance its ability to absorb and regenerate carbon dioxide. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of low carbon dioxide absorption capacity and slow absorption rate of existing decarbonizing agents, and to provide a composite amine decarbonizing agent and its application, as well as a carbon dioxide capture method. The decarbonizing agent can maintain a high carbon dioxide absorption rate while improving carbon dioxide absorption efficiency, absorption performance, and regeneration performance.

[0005] To achieve the above objectives, the first aspect of the present invention provides a composite amine decarbonizing agent, wherein the decarbonizing agent comprises a main absorbent, a co-absorbent, a solvent, and an optional antioxidant;

[0006] Of which, based on a total mass of 100wt% of the decarbonizing agent, the content of the main absorbent is 40-60wt%, the content of the auxiliary absorbent is 2-5wt%, the content of the antioxidant is 0-1wt%, and the content of the solvent is 35-58wt%.

[0007] The primary absorbent is diethylaminoethanol; the secondary absorbent is piperazine.

[0008] Preferably, based on 100wt% of the total mass of the decarbonizing agent, the content of the main absorbent is 45-55wt%, the content of the auxiliary absorbent is 3-4wt%, the content of the antioxidant is 0.1-0.5wt%, and the content of the solvent is 41-51wt%.

[0009] Preferably, the mass ratio of the primary absorbent to the co-absorbent is 11-20:1, more preferably 13-17:1.

[0010] Preferably, the antioxidant is sodium potassium tartrate and / or sodium sulfite.

[0011] Preferably, the solvent is water and / or a physical solvent.

[0012] Preferably, the solvent is water or a physical solvent.

[0013] Preferably, the mass ratio of water to physical solvent in the solvent is 1:0-0.5, and more preferably 1:0.05-0.3.

[0014] Preferably, the physical solvent is selected from at least one of N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, and sulfolane.

[0015] The second aspect of this invention provides the application of the composite amine decarbonizing agent described in the first aspect in the field of carbon dioxide capture in waste gas treatment.

[0016] A third aspect of the present invention provides a method for capturing carbon dioxide, wherein the carbon dioxide is absorbed and regenerated using the decarbonizing agent described in the first aspect.

[0017] The superior effects achieved through the above technical solution are as follows:

[0018] This invention provides a composite amine decarbonization agent. By adjusting the content of the main absorbent diethylaminoethanol, the co-absorbent piperazine, and the solvent, a tertiary amine with lower regeneration energy consumption is used as the main absorbent to reduce the reaction energy consumption during regeneration. Piperazine, with its good absorption performance, is used as the co-absorbent. This method can maintain a high carbon dioxide absorption rate while improving carbon dioxide absorption efficiency and absorption performance. While maintaining a high absorption rate, it effectively reduces the heat consumption during regeneration, thereby effectively reducing the emission of carbon dioxide and other harmful gases in industrial production. Attached Figure Description

[0019] Figure 1 These are the test results of the carbon dioxide absorption performance of the decarbonizing agents in the embodiments and comparative examples of this invention;

[0020] Figure 2 These are the test results of the carbon dioxide regeneration performance of the decarbonizing agent in the embodiments and comparative examples of the present invention. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] The first aspect of the present invention provides a composite amine decarbonizing agent, wherein the decarbonizing agent comprises a main absorbent, a co-absorbent, a solvent, and an optional antioxidant;

[0023] Of which, based on a total mass of 100wt% of the decarbonizing agent, the content of the main absorbent is 40-60wt%, the content of the auxiliary absorbent is 2-5wt%, the content of the antioxidant is 0-1wt%, and the content of the solvent is 35-58wt%.

[0024] The primary absorbent is diethylaminoethanol; the secondary absorbent is piperazine.

[0025] In this invention, by adjusting the content of the main absorbent diethylaminoethanol, the co-absorbent piperazine, and the solvent, a tertiary amine with lower regeneration energy consumption is used as the main absorbent to reduce the reaction energy consumption during regeneration. Piperazine, with its better absorption performance, is used as the co-absorbent. This approach maintains a high carbon dioxide absorption rate while improving carbon dioxide absorption efficiency and absorption performance. While maintaining a high absorption rate, it effectively reduces heat consumption during regeneration, thereby effectively reducing the emissions of harmful gases such as carbon dioxide in industrial production.

[0026] According to the present invention, preferably, based on 100 wt% of the total mass of the decarbonizing agent, the content of the main absorbent is 45-55 wt%, for example 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55 wt%, or any range between the two, and the content of the auxiliary absorbent is 3-4 wt%, for example 3 wt%, 3.2 wt%, 3.4 wt%, 3.5 wt%, 3.6 wt%, 3.8 wt%, 4 wt%, or any range between the two. The antioxidant content is 0.1-0.5 wt%, for example, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, 0.5 wt%, or any range between the two; the solvent content is 41-51 wt%, for example, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, 51 wt%, or any range between the two.

[0027] According to the present invention, preferably, the mass ratio of the main absorbent to the co-absorbent is 11-20:1, for example 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, or any range between the two, preferably 13-17:1. In this invention, the mass ratio of the main absorbent to the co-absorbent is further limited to ensure that the decarbonizing agent has a high carbon dioxide absorption capacity while also possessing carbon dioxide regeneration capacity.

[0028] According to the present invention, preferably, the antioxidant is sodium potassium tartrate and / or sodium sulfite. In this invention, the above-mentioned antioxidant is used in combination with the main absorbent and the co-absorbent to improve the antioxidant properties of the decarbonizing agent and extend its service life without affecting the absorption effect of the decarbonizing agent system.

[0029] According to the present invention, preferably, the solvent is water and / or a physical solvent.

[0030] According to the present invention, preferably, the solvent is water and a physical solvent.

[0031] According to the present invention, preferably, the mass ratio of water to physical solvent in the solvent is 1:0-0.5, for example 1:0.01, 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5, or any range between the two, preferably 1:0.05-0.3.

[0032] According to the present invention, preferably, the physical solvent is selected from at least one of N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide and sulfolane.

[0033] In this invention, the physical solvent is mixed with water in the above proportion, and the resulting solvent has a high carbon dioxide absorption rate and excellent regeneration performance. The addition of the physical solvent further improves the absorption performance.

[0034] In this invention, the preparation method of the decarbonizing agent is not particularly limited; the decarbonizing agent can be obtained by mixing the components contained in the decarbonizing agent evenly.

[0035] According to a preferred embodiment of the present invention, the method for preparing the decarbonizing agent includes: mixing a main absorbent, a co-absorbent, a solvent, and an antioxidant in the above-mentioned proportions to obtain the decarbonizing agent. The mixing method is not particularly limited; those skilled in the art can use conventional mixing methods, preferably mechanical mixing.

[0036] The second aspect of this invention provides the application of the composite amine decarbonizing agent described in the first aspect in the field of carbon dioxide capture in waste gas treatment.

[0037] In this invention, the decarbonizing agent exhibits excellent absorption and regeneration performance, reducing energy consumption during carbon dioxide regeneration and achieving a greater regeneration rate within the same timeframe. It can be applied to waste gas treatment in industries such as steel, chemicals, and power, and can also be used in environmental protection and energy development, demonstrating broad application prospects and market value.

[0038] A third aspect of the present invention provides a method for capturing carbon dioxide, wherein the carbon dioxide is absorbed and regenerated using the decarbonizing agent described in the first aspect.

[0039] In this invention, the absorption and regeneration conditions of carbon dioxide are not particularly limited, and those skilled in the art can adapt the absorption and regeneration conditions of carbon dioxide according to the absorption and regeneration situation.

[0040] According to the present invention, preferably, the absorption conditions for carbon dioxide include: an absorption temperature of 20-60°C and an absorption pressure of atmospheric pressure.

[0041] According to the present invention, preferably, the regeneration conditions of the carbon dioxide include: a regeneration temperature of 100-150°C, more preferably 110-130°C.

[0042] According to the present invention, preferably, the method includes the following steps:

[0043] (1) Carbon dioxide is introduced into the decarbonizing agent described in the first aspect to absorb carbon dioxide and obtain carbon dioxide-rich liquid.

[0044] (2) The carbon dioxide-rich solution is heated and regenerated to obtain a lean solution and regenerated carbon dioxide. The lean solution is used for carbon dioxide absorption, and the regenerated carbon dioxide is recovered.

[0045] According to a preferred embodiment of the present invention, the carbon dioxide absorption capacity of the decarbonizing agent is determined by the following process, including an absorption process and a regeneration process;

[0046] The absorption process includes: the decarbonizing agent absorbs carbon dioxide at 20-50℃ and normal pressure, and samples are taken at 30 min, 60 min, 90 min, 120 min, 180 min, 240 min and 300 min to test the carbon dioxide content in the absorption liquid after the decarbonizing agent absorbs carbon dioxide.

[0047] The regeneration process includes: regenerating the absorbent at 100-140℃ under normal pressure, and taking samples at 5 min, 10 min, 20 min, 30 min and 60 min to test the carbon dioxide content in the sample absorbent.

[0048] In this invention, the equipment used for the absorption and regeneration processes is not particularly limited; any commonly used container will suffice. The temperature of the decarbonizing agent is maintained to meet the absorption and regeneration temperatures by water bath heating and / or oil bath heating.

[0049] According to a particularly preferred embodiment of the present invention, a method for capturing carbon dioxide includes:

[0050] A composite amine-based decarbonization agent is used for the absorption and regeneration of carbon dioxide;

[0051] The decarbonizing agent comprises a main absorbent, a co-absorbent, a solvent, and an optional antioxidant. Based on a total mass of 100 wt% of the decarbonizing agent, the main absorbent content is 45-55 wt%, the co-absorbent content is 3-4 wt%, the antioxidant content is 0.1-0.5 wt%, and the solvent content is 41-51 wt%.

[0052] The mass ratio of the main absorbent to the co-absorbent is 13-17:1;

[0053] The mass ratio of water to physical solvent in the solvent is 1:0.05-0.3;

[0054] The physical solvent is selected from at least one of N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, and sulfolane.

[0055] The present invention will be described in detail below through examples and comparative examples. Unless otherwise specified, all reagents used in the following examples and comparative examples are commercially available.

[0056] Example 1

[0057] In the decarbonizing agent provided in this embodiment, the main absorbent is diethylaminoethanol (DEEA), with an addition amount of 40 wt%. The auxiliary absorbent is piperazine, with an addition amount of 2 wt%, and the remainder is a solvent, namely water.

[0058] Example 2

[0059] In the decarbonization agent provided in this embodiment, the main absorbent is diethylaminoethanol (DEEA), with an addition amount of 50 wt%. The auxiliary absorbent is piperazine, with an addition amount of 3 wt%, and the remainder is a solvent, namely water.

[0060] Example 3

[0061] In the decarbonization agent provided in this embodiment, the main absorbent is diethylaminoethanol (DEEA), with an addition amount of 50 wt%. The auxiliary absorbent is piperazine, with an addition amount of 4 wt%, and the remainder is a solvent, namely water.

[0062] Example 4

[0063] In the decarbonization agent provided in this embodiment, the main absorbent is diethylaminoethanol (DEEA), with an addition amount of 60 wt%. The auxiliary absorbent is piperazine, with an addition amount of 5 wt%, and the remainder is a solvent, namely water.

[0064] Example 5

[0065] In the decarbonization agent provided in this embodiment, the main absorbent is diethylaminoethanol (DEEA), with an addition amount of 50 wt%. The co-absorbent is piperazine, with an addition amount of 3 wt%. The antioxidant is potassium sodium tartrate, with an addition amount of 0.1 wt%. The solvent includes water and a physical solvent, with the solvent addition amount of 46.9 wt%. The physical solvent is N-methylpyrrolidone, with the physical solvent addition amount of 4 wt%, and the remainder being water.

[0066] Example 6

[0067] In the decarbonization agent provided in this embodiment, the main absorbent is diethylaminoethanol (DEEA), with an addition amount of 50 wt%. The auxiliary absorbent is piperazine, with an addition amount of 3 wt%. The solvent contains water and a physical solvent, with a solvent content of 47 wt%. The physical solvent is N-methylpyrrolidone, with a physical solvent content of 2 wt%, and the remainder is water.

[0068] Comparative Example 1

[0069] In the decarbonization agent provided in this comparative example, the absorbent is diethylaminoethanol (DEEA), with an addition amount of 50 wt%. The solvent is water and a physical solvent, with a solvent content of 50 wt%. The physical solvent is N-methylpyrrolidone, with a physical solvent content of 4 wt% and the remainder being water.

[0070] Comparative Example 2

[0071] In the decarbonization agent provided in this comparative example, the main absorbent is piperazine, with an addition amount of 20 wt%. The solvent includes water and a physical solvent, with a solvent content of 80 wt%, of which the addition amount of physical solvent is 4 wt%, the physical solvent is N-methylpyrrolidone, and the remainder is water.

[0072] Comparative Example 3

[0073] In the decarbonization agent provided in this comparative example, the main absorbent is diethylaminoethanol (DEEA), with an addition amount of 50 wt%; the auxiliary absorbent is N-aminoethylpiperazine, with an addition amount of 3 wt%; and the antioxidant is potassium sodium tartrate, with an addition amount of <0.1 wt%. The solvent includes water and physical solvents, with a solvent content of 46.9 wt%. The physical solvent is dimethyl sulfoxide, with an addition amount of 4 wt%, and the remainder is water.

[0074] Test case

[0075] The carbon dioxide absorption and regeneration performance of the decarbonizing agents in the examples and comparative examples were tested.

[0076] Absorption process: 100 mL of the prepared decarbonizing agent was poured into a three-necked flask and placed in a 40°C constant temperature water bath. Absorption was carried out under normal pressure for 300 min to obtain the absorption solution. Samples were taken at 30 min, 60 min, 90 min, 120 min, 180 min, 240 min and 300 min to measure the carbon dioxide content in the sample absorption solution.

[0077] Regeneration process: The sample absorption liquid after carbon dioxide absorption for 300 min was poured into a three-necked flask and placed in a constant temperature oil bath at 120℃. Regeneration was carried out under normal pressure to obtain regenerated liquid. Samples were taken at 5 min, 10 min, 20 min, 30 min and 60 min to measure the carbon dioxide content in the regenerated liquid. The results are shown in Table 1.

[0078] Table 1

[0079]

[0080] Figure 1 The results show the carbon dioxide absorption performance test results of the decarbonization agents in the examples and comparative examples. Figure 2 The carbon dioxide regeneration performance test results of the decarbonizing agents in the examples and comparative examples are shown in Table 1. Figure 1 and Figure 2 As can be seen, in this embodiment of the invention, with diethylaminoethanol (DEEA) as the main absorbent at an addition amount of 45-55 wt%, piperazine as the co-absorbent at an addition amount of 3-4 wt%, and water and physical solvents used together as solvents, and with one or both of potassium sodium tartrate and sodium sulfite as antioxidants at an addition amount of <0.5 wt%, the decarbonizing agent maintains the high absorption rate of traditional amine solutions while also maintaining excellent regeneration performance. The addition of a small amount of physical solvent can further improve the absorption performance.

[0081] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A composite amine decarbonizing agent, characterized in that, The decarbonizing agent comprises a primary absorbent, a co-absorbent, a solvent, and an optional antioxidant; Of which, based on a total mass of 100wt% of the decarbonizing agent, the content of the main absorbent is 40-60wt%, the content of the auxiliary absorbent is 2-5wt%, the content of the antioxidant is 0-1wt%, and the content of the solvent is 35-58wt%. The primary absorbent is diethylaminoethanol; the secondary absorbent is piperazine.

2. The decarbonizing agent according to claim 1, wherein, Based on a total mass of 100wt% of the decarbonizing agent, the content of the main absorbent is 45-55wt%, the content of the auxiliary absorbent is 3-4wt%, the content of the antioxidant is 0.1-0.5wt%, and the content of the solvent is 41-51wt%. Preferably, the mass ratio of the primary absorbent to the co-absorbent is 11-20:1, more preferably 13-17:

1.

3. The decarbonizing agent according to claim 1 or 2, wherein, The antioxidant is potassium sodium tartrate and / or sodium sulfite.

4. The decarbonizing agent according to any one of claims 1-3, wherein, The solvent is water and / or a physical solvent; Preferably, the solvent is water or a physical solvent.

5. The decarbonizing agent according to claim 4, wherein, The mass ratio of water to physical solvent in the solvent is 1:0-0.5, preferably 1:0.05-0.

3.

6. The decarbonizing agent according to claim 4 or 5, wherein, The physical solvent is selected from at least one of N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, and sulfolane.

7. The application of the composite amine decarbonizing agent according to any one of claims 1-6 in the field of waste gas treatment for capturing carbon dioxide.

8. A method for capturing carbon dioxide, characterized in that, Carbon dioxide absorption and regeneration are carried out using the decarbonizing agent described in any one of claims 1-6.

9. The method according to claim 8, wherein, The absorption conditions for carbon dioxide include: an absorption temperature of 20-60℃ and an absorption pressure of atmospheric pressure. Preferably, the regeneration conditions for the carbon dioxide include a regeneration temperature of 100-150°C, more preferably 110-130°C.

10. The method according to claim 8 or 9, wherein, The method includes the following steps: (1) Carbon dioxide is introduced into the decarbonizing agent according to any one of claims 1-6 to absorb carbon dioxide and obtain carbon dioxide-rich liquid; (2) The carbon dioxide-rich solution is heated and regenerated to obtain a lean solution and regenerated carbon dioxide. The lean solution is used for carbon dioxide absorption, and the regenerated carbon dioxide is recovered.

Images