Organic amine composite absorbent for carbon capture and application thereof

Abstract

The invention discloses an organic amine composite absorbent for carbon capture and application thereof, and belongs to the technical field of carbon dioxide capture, the organic amine composite absorbent for carbon capture is in a solution state and comprises the following components: a main agent, an auxiliary agent, an accelerant A, an accelerant B and water; wherein the mass ratio of the main agent to the auxiliary agent is 2: (1-2); the mass ratio of the auxiliary agent to the accelerant A is 2: (1-2); the mass ratio of the accelerant A to the accelerant B is 2: (1-2); the total mass concentration of the main agent, the auxiliary agent, the accelerant A and the accelerant B in the organic amine composite absorbent for carbon capture is 30-40 wt%; the main agent is selected from N-methyldiethanolamine or N, N-diethyl ethanolamine, the auxiliary agent is selected from piperazine or hydroxyethyl ethylenediamine, the accelerant A is selected from triethylene glycol monomethyl ether and / or ethylene glycol monomethyl ether, and the accelerant B is selected from ethyl butyl ether and / or isobutyl ether. The organic amine composite absorbent for carbon capture has a wide application prospect in removal of carbon dioxide in flue gas.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture, and in particular to an organic amine composite absorbent for carbon capture and applications thereof. Background Art

[0002] With the acceleration of industrialization, carbon dioxide (CO2), a major greenhouse gas, has seen increasing emissions, significantly impacting the global climate. To address this challenge, carbon dioxide capture, utilization, and storage (CCUS) has emerged as a key technological approach to reducing CO2 emissions. Among the various capture technologies, post-combustion capture (CCUS) has attracted significant attention due to its lack of need for large-scale modifications to existing thermal power plants. Chemical absorption, with its mature technology and high application potential, has become a research hotspot. In chemical absorption, CO2 is captured through a chemical reaction between an absorbent (typically an organic amine compound) and CO2 in the flue gas. However, in actual operation, the performance of the absorbent is affected by various factors, such as the loading of the absorbent (i.e., the amount of dissolved CO2 in the absorbent) and the concentration of the absorbent.

[0003] The performance of chemical absorbents is a key factor in determining the effectiveness of chemical absorption capture. Ethanolamine (MEA) is the first monoamine absorbent to be commercialized. Since ethanolamine is a primary amine, it has the advantage of fast absorption rate, but its disadvantages such as low regeneration efficiency, high regeneration energy consumption, and strong corrosiveness limit its large-scale application. Primary and secondary amines mainly use carbamate as the absorption product, which has advantages in absorption reaction kinetics; tertiary amines mainly use HCO3 - As an absorption product, its absorption reaction rate is slow, but the regeneration efficiency is high and the regeneration energy consumption is small. In addition, there is a type of hindered amine. Under the influence of intramolecular steric hindrance, the carbamate produced by hindered amine absorbing CO2 is unstable and easily hydrolyzed to generate HCO3. - , so it has both good absorption and desorption performance and low regeneration energy consumption.

[0004] For example, Chinese patent document CN103394277A discloses an organic amine composite absorbent for removing carbon dioxide from coal-fired flue gas, which comprises: 10% to 45% of a main absorbent component, 0% to 10% of an auxiliary absorbent component, 0.01% to 6% of a corrosion inhibitor, 0.01% to 3% of an antioxidant, 0% to 5% of a defoaming agent, and the balance being water; wherein the main absorbent component comprises: monoethanolamine MEA, 2-amino-2-methyl-1-propanol AMP, piperazine, N-aminoethylpiperazine AEP, aminoethylethanolamine AEEA, and N-methylmonoethanolamine MMEA; and the auxiliary absorbent component comprises at least one of diethanolamine DEA, diethylenetriamine DETA, triethylenetetramine TETA, N-methyldiethanolamine MDEA, cyclopentane sulfone, and tert-butylaminoethoxyethanol TBEE. Chinese patent document CN117379936A discloses a ternary composite organic amine absorbent for capturing carbon dioxide and its application. The absorbent comprises at least a mixed aqueous solution of ethanolamine, 2-amino-2-methyl-1-propanol, piperazine, and water. In the mixed aqueous solution, the total mass fraction of ethanolamine, 2-amino-2-methyl-1-propanol, and piperazine is 20-40%, and the mass fraction ratio of 2-amino-2-methyl-1-propanol to piperazine is 1:1. This invention can fully utilize the reaction characteristics and advantages of sterically hindered amines, cyclic amines, and primary amine absorbents.

[0005] The above inventions are all aimed at mixing different types of amines (primary amines, secondary amines, tertiary amines, hindered amines, etc.) to achieve synergistic effects between different amines and to develop mixed amine absorbents with better overall performance. However, the above inventions may still have deficiencies in the balance of absorption and desorption performance and cannot achieve the desired effect. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the present invention provides an organic amine composite absorbent for carbon capture, which effectively balances the absorption and desorption performance. At a mass concentration of 30% amine, the absorption capacity reaches 0.72 molCO2 per 1 mol solution, the average absorption rate can reach 0.0022 mol / min, and the desorption amount reaches 0.5832 mol CO2.

[0007] The specific technical solutions adopted are as follows: An organic amine composite absorbent for carbon capture, which is in a solution state and consists of the following components: a main agent, an auxiliary agent, a accelerator A, a accelerator B and water; Among them, the mass ratio of the main agent to the auxiliary agent is 2:1-2; the mass ratio of the auxiliary agent to the accelerator A is 2:1-2; the mass ratio of the accelerator A to the accelerator B is 2:1-2; The total mass concentration of the main agent, auxiliary agent, accelerator A and accelerator B in the organic amine composite absorbent for carbon capture is 30-40 wt%; The main agent is a tertiary amine alcohol compound, the auxiliary agent is a polyamine compound, the accelerator A is selected from triethylene glycol monomethyl ether and / or ethylene glycol monomethyl ether, and the accelerator B is selected from ethyl butyl ether and / or isobutyl ether.

[0008] Tertiary amine alcohol compounds are the main active ingredients of the absorbent, which are responsible for chemical reaction with carbon dioxide to achieve carbon dioxide absorption. The main product formed by tertiary amine alcohol compounds (such as N-methyldiethanolamine or N,N-diethylethanolamine) during the absorption process is bicarbonate (HCO3 - ), its absorption reaction rate is slow, but its regeneration efficiency is high and its regeneration energy consumption is low. This allows the absorbent to release carbon dioxide more efficiently and restore its activity during the desorption process. The main function of polyamine compounds is to increase the absorption rate and absorption capacity of the absorbent. Polyamine compounds (such as piperazine or hydroxyethylethylenediamine) have multiple amino groups and can form multiple chemical bonds with carbon dioxide. The main product formed by polyamine compounds during the absorption process is carbamate, which has a fast absorption reaction rate and can absorb large amounts of carbon dioxide in a short period of time. By combining with the main agent, the absorption performance of the absorbent can be significantly improved.

[0009] Accelerators A and B can promote the diffusion and reaction of carbon dioxide in the absorbent through physical or chemical effects, thereby increasing the absorption rate. Simultaneously, during the desorption process, they can reduce the absorbent's viscosity, thus reducing desorption energy consumption. Experiments have shown that the addition of Accelerators A and B has a positive effect on improving regeneration efficiency, but different combinations and ratios of the accelerators have varying effects on regeneration efficiency. Specific combinations and ratios of Accelerators A and B can further optimize regeneration efficiency.

[0010] Furthermore, the tertiary amine alcohol compound is selected from N-methyldiethanolamine or N,N-diethylethanolamine.

[0011] Furthermore, the polyamine compound is selected from piperazine or hydroxyethylethylenediamine.

[0012] Preferably, the total mass concentration of the main agent, auxiliary agent, promoter A and promoter B in the organic amine composite absorbent for carbon capture is 40wt%, the mass ratio of the main agent to the auxiliary agent is 2:1; the mass ratio of the auxiliary agent to promoter A is 2:1; and the mass ratio of promoter A to promoter B is 1:1.

[0013] Furthermore, when the organic amine composite absorbent for carbon capture absorbs carbon dioxide, the applicable absorption temperature range is 30 to 60° C., and the operating pressure is normal pressure (0.09 to 0.11 MPa).

[0014] Furthermore, when the organic amine composite absorbent that has absorbed carbon dioxide desorbs carbon dioxide, the desorption conditions are 90 to 120° C. and the operating pressure is 10 to 30 kPa (preferably 20 kPa).

[0015] The present invention also provides a method for removing carbon dioxide from flue gas, comprising: contacting flue gas containing carbon dioxide with the organic amine composite absorbent for carbon capture.

[0016] Preferably, the contact method is countercurrent contact, the volume concentration of carbon dioxide in the flue gas containing carbon dioxide is in the range of 10% to 30%, and the gas-liquid ratio is 250 to 350 Nm 3 / m 3 .

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention fully combines the advantages of various organic amines and effectively balances the absorption and desorption performance through the synergistic effect between different amines. In addition, the organic amine composite absorbent of the present invention significantly improves the absorption capacity of the absorbent for carbon dioxide by rationally matching the main agent, auxiliary agent, promoter A and promoter B. The absorption load reaches 0.72 mol / mol, which is significantly improved compared with the 0.52 mol / mol of the traditional ethanolamine (MEA) absorbent. This means that at the same absorbent dosage, the organic amine composite absorbent of the present invention can absorb more carbon dioxide, thereby improving the efficiency of carbon dioxide capture, reducing the amount of absorbent used and the scale of equipment, and reducing the capture cost.

[0018] The organic amine composite absorbent of the present invention has a fast absorption rate and can quickly react with carbon dioxide in the initial stage of absorption. The absorption rate reaches 0.0022 mol / min, which is significantly higher than that of traditional ethanolamine (MEA) absorbents. In other words, the organic amine composite absorbent of the present invention can absorb a large amount of carbon dioxide in a relatively short period of time, accelerate the removal rate of carbon dioxide from flue gas, help to achieve a fast and efficient carbon dioxide capture process, improve the system's processing capacity, and enable it to better adapt to the treatment needs of large-scale industrial flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The absorption load curves of Examples 1-4 and Comparative Examples 1-4 in the absorption experiment of the present invention are shown; Figure 2 Statistical diagram of regeneration efficiency after desorption of Examples 1-4 of the present invention and Comparative Examples 1-4. DETAILED DESCRIPTION

[0020] In order to make the objects, features and advantages of the present invention more clearly understood, a detailed description is given below using specific embodiments. In the following description, many specific details are set forth to fully understand the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The technical features in the various embodiments of the present invention can be combined accordingly without conflicting with each other.

[0021] The procedures for the following examples, in which specific conditions are not specified, generally follow conventional conditions or those recommended by the manufacturer. Any material not described in detail in this specification belongs to the prior art known to those skilled in the art. The experimental materials used in the following examples, unless otherwise specified, can be purchased from conventional biochemical reagent companies.

[0022] The present invention mainly develops an organic amine composite absorbent for carbon capture, which is in solution and consists of the following components: a main agent, an auxiliary agent, a promoter A, a promoter B, and water; wherein the mass ratio of the main agent to the auxiliary agent is 2:1-2; the mass ratio of the auxiliary agent to the promoter A is 2:1-2; and the mass ratio of the promoter A to the promoter B is 2:1-2. The total mass concentration of the main agent, auxiliary agent, accelerator A and accelerator B in the organic amine composite absorbent for carbon capture is 30-40 wt%; The main agent is selected from N-methyldiethanolamine or N,N-diethylethanolamine, the auxiliary agent is selected from piperazine or hydroxyethylethylenediamine, the accelerator A is selected from triethylene glycol monomethyl ether and / or ethylene glycol monomethyl ether, and the accelerator B is selected from ethyl butyl ether and / or isobutyl ether.

[0023] Example 1 In this embodiment, the organic amine composite absorbent for carbon capture is composed of a main agent N-methyldiethanolamine, an auxiliary agent piperazine, a promoter A triethylene glycol monomethyl ether, a promoter B butyl ether, and water. Specifically, 20 g of N-methyldiethanolamine, 10 g of piperazine, 5 g of triethylene glycol monomethyl ether, 5 g of butyl ether, and 60 g of deionized water are taken and uniformly mixed to obtain a total of 100 g of the organic amine composite absorbent for carbon capture, which is set aside.

[0024] Example 2 In this embodiment, the organic amine composite absorbent for carbon capture is composed of a main agent N,N-diethylethanolamine, an auxiliary agent hydroxyethylethylenediamine, a promoter A ethylene glycol monomethyl ether, a promoter B isobutyl ether, and water. Specifically, 20 g of N,N-diethylethanolamine, 10 g of hydroxyethylethylenediamine, 5 g of ethylene glycol monomethyl ether, 5 g of isobutyl ether, and 60 g of deionized water are taken and uniformly mixed to obtain a total of 100 g of the organic amine composite absorbent for carbon capture, which is set aside.

[0025] Example 3 In this embodiment, the organic amine composite absorbent for carbon capture is composed of a main agent N-methyldiethanolamine, an auxiliary agent piperazine, a promoter A ethylene glycol monomethyl ether, a promoter B isobutyl ether, and water. Specifically, 20 g of N-methyldiethanolamine, 10 g of piperazine, 5 g of ethylene glycol monomethyl ether, 5 g of isobutyl ether, and 60 g of deionized water are taken and uniformly mixed to obtain a total of 100 g of the organic amine composite absorbent for carbon capture, which is set aside.

[0026] Example 4 In this embodiment, the organic amine composite absorbent for carbon capture is composed of a main agent N,N-diethylethanolamine, an auxiliary agent hydroxyethylethylenediamine, a promoter A triethylene glycol monomethyl ether, a promoter B butyl ether, and water. Specifically, 20 g of N,N-diethylethanolamine, 10 g of hydroxyethylethylenediamine, 5 g of triethylene glycol monomethyl ether, 5 g of butyl ether, and 60 g of deionized water are taken and uniformly mixed to obtain a total of 100 g of the organic amine composite absorbent for carbon capture, which is set aside.

[0027] Comparative Example 1 A conventional ethanolamine (MEA) absorbent was used as a sample of comparative example 1. Specifically, 30 g of ethanolamine (MEA) and 70 g of deionized water were uniformly mixed to prepare 100 g of a 30 wt% MEA absorbent for later use.

[0028] Comparative Example 2 In this comparative example, the composite absorbent is composed of a main agent N-methyldiethanolamine, an auxiliary agent piperazine, a promoter A triethylene glycol monomethyl ether and water. Specifically, 20 g of N-methyldiethanolamine, 10 g of piperazine, 5 g of triethylene glycol monomethyl ether and 65 g of deionized water are taken respectively, and after uniform mixing, a total of 100 g of composite absorbent is obtained for standby use.

[0029] Comparative Example 3 In this comparative example, the composite absorbent is composed of a main agent N,N-diethylethanolamine, an auxiliary agent piperazine, a promoter B butyl ether and water. Specifically, 20 g of N,N-diethylethanolamine, 10 g of piperazine, 5 g of butyl ether and 65 g of deionized water are taken respectively, and after uniform mixing, a total of 100 g of composite absorbent is obtained for standby use.

[0030] Comparative Example 4 In this comparative example, the composite absorbent is composed of a main agent N,N-diethylethanolamine, an auxiliary agent piperazine and water. Specifically, 20 g of N,N-diethylethanolamine, 10 g of piperazine and 70 g of deionized water are taken respectively, and after uniform mixing, a total of 100 g of composite absorbent is obtained for standby use.

[0031] Sample analysis (1) Carbon dioxide absorption experiment Take 25 mL of the absorbent in Examples 1-4 and Comparative Examples 1-4, respectively, pour it into a bubbling absorption tube and place it in a water bath at 40°C to maintain a constant temperature. A simulated flue gas mixture of 15% CO2 + 75% N2 (volume ratio) is introduced at a constant flow rate until it reaches the absorbent. The absorption experiment lasts for 1 hour, and the operating pressure is atmospheric pressure (0.09-0.11 MPa). At the outlet of the absorption tube, the change in the absorption rate of the solution over time is obtained by a soap film flowmeter. The absorption load can be obtained by integrating the absorption rate over time. In addition, after the absorption is completed, the CO2 load in the rich solution is determined by sulfuric acid hydrolysis. The results are shown in Tables 1 and Figure 1 shown.

[0032] Table 1 CO2 absorption performance of absorbents in Examples 1-4 and Comparative Examples 1-4

[0033] Table 1 shows the carbon dioxide absorption performance of the absorbents in Examples 1-4 and Comparative Examples 1-4, specifically including two indicators: absorption load (mol / mol) and initial absorption load (mol / min). Absorption load: The absorption load reflects the ability of the absorbent to absorb carbon dioxide per unit time. As can be seen from Table 1, Example 1 has the highest absorption load, reaching 0.72 mol / mol, while Comparative Example 1 (traditional ethanolamine MEA absorbent) has an absorption load of 0.52 mol / mol. This indicates that the composite absorbent of the present invention has a higher capacity for carbon dioxide absorption and can absorb more carbon dioxide. Initial absorption load: The initial absorption load reflects the reaction rate of the absorbent in the initial absorption stage. The initial absorption load of Example 1 is 0.0022 mol / min, which is significantly higher than that of the other Examples and Comparative Examples. This indicates that the absorbent of the present invention can react quickly with carbon dioxide in the initial absorption stage and has a high absorption rate.

[0034] Figure 1 This is the absorption load curve in the absorption experiment. The curve can be used to more intuitively observe the changes in the absorption load of the absorbent at different time points. Figure 1 It can be seen that the absorption load curve of Example 1 rises fastest in the initial stage, indicating that it has a higher absorption rate in the initial stage of absorption. As time goes by, the absorption load gradually stabilizes, but the curve of Example 1 remains at a high level, indicating that it maintains good absorption performance throughout the entire absorption process. Absorption stability: Figure 1 The absorption load curve of Example 1 is relatively stable, without obvious fluctuations, which indicates that the absorbent of the present invention has good stability during the absorption process and can continuously and stably absorb carbon dioxide.

[0035] (2) Carbon dioxide desorption experiment The absorbent samples after absorbing CO2 in Examples 1-4 and Comparative Example 1 were placed in a magnetic stirrer and heated for desorption in a constant temperature oil bath at 20 kPa, 200 rpm, and 105°C for 1.5 h. After the desorption experiment was completed, the CO2 load in the lean solution was determined by sulfuric acid hydrolysis. The results are shown in Table 2 and Figure 2 shown.

[0036] Table 2 CO2 desorption performance of absorbents in Examples 1-4 and Comparative Examples 1-4

[0037] Table 2 shows the CO2 desorption performance of the absorbents in Examples 1-4 and Comparative Examples 1-4, specifically including the regeneration efficiency (%). Regeneration efficiency reflects the ability of an absorbent to release CO2 during the desorption process and is an important indicator for evaluating its recycling performance. As shown in Table 2, Example 1 achieves the highest regeneration efficiency, reaching 81%, while Comparative Example 1 (a traditional ethanolamine MEA absorbent) achieves only 42%. This demonstrates that the composite absorbent of the present invention exhibits higher CO2 desorption efficiency, effectively releasing absorbed CO2 and restoring absorbent activity. The role of the promoter: The regeneration efficiencies of Examples 2, 3, and 4 were 69%, 71%, and 67%, respectively, all higher than Comparative Example 1 but lower than Example 1. This demonstrates that the addition of promoters A and B has a positive effect on improving regeneration efficiency, but different promoter combinations and ratios have varying effects on regeneration efficiency. The specific combination and ratio of promoters A and B in Example 1 can further optimize regeneration efficiency.

[0038] Figure 2 The bar chart shows the regeneration efficiency after desorption. The bar chart can be used to more intuitively compare the regeneration efficiency of different absorbents. Figure 2 It can be seen that the regeneration efficiency histogram of Example 1 is significantly higher than that of other examples and comparative examples, which is consistent with the data in Table 2. Figure 2 The advantages of the absorbent of the present invention in terms of regeneration efficiency are intuitively demonstrated, especially when compared with other comparative examples, where this advantage is more obvious. Figure 2 The effect of different promoter combinations on regeneration efficiency is also shown. The specific combination of promoter A and promoter B in Example 1 performs best in terms of regeneration efficiency, indicating that there is a synergistic effect between promoters A and B, which can significantly improve the regeneration efficiency of the absorbent.

[0039] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An organic amine composite absorbent for carbon capture, characterized in that: The organic amine composite absorbent for carbon capture is in a liquid state and is composed of the following components: a main agent, an auxiliary agent, a promoter A, a promoter B, and water; wherein the mass ratio of the main agent to the auxiliary agent is 2:1-2; the mass ratio of the auxiliary agent to the promoter A is 2:1-2; and the mass ratio of the promoter A to the promoter B is 2:1-2. The total mass concentration of the main agent, auxiliary agent, accelerator A and accelerator B in the organic amine composite absorbent for carbon capture is 30-40wt%; The main agent is a tertiary amine alcohol compound, the auxiliary agent is a polyamine compound, the accelerator A is selected from triethylene glycol monomethyl ether and / or ethylene glycol monomethyl ether, and the accelerator B is selected from ethyl butyl ether and / or isobutyl ether.

2. The organic amine composite absorbent for carbon capture according to claim 1, characterized in that: The tertiary amine alcohol compound is selected from N-methyldiethanolamine or N,N-diethylethanolamine.

3. The organic amine composite absorbent for carbon capture according to claim 1, characterized in that: The polyamine compound is selected from piperazine or hydroxyethylethylenediamine.

4. The organic amine composite absorbent for carbon capture according to claim 1, characterized in that: The total mass concentration of the main agent, auxiliary agent, promoter A and promoter B in the organic amine composite absorbent for carbon capture is 40wt%, the mass ratio of the main agent to the auxiliary agent is 2:1; the mass ratio of the auxiliary agent to promoter A is 2:1; and the mass ratio of promoter A to promoter B is 1:

1.

5. The organic amine composite absorbent for carbon capture according to claim 1, characterized in that: When the organic amine composite absorbent for carbon capture absorbs carbon dioxide, the applicable absorption temperature range is 30-60° C. and the operating pressure is 0.09-0.11 MPa.

6. The organic amine composite absorbent for carbon capture according to claim 1, characterized in that: When the organic amine composite absorbent that has absorbed carbon dioxide desorbs carbon dioxide, the desorption conditions are 90 to 120° C. and the operating pressure is 10 to 30 kPa.

7. A method for removing carbon dioxide from flue gas, characterized in that: include: Flue gas containing carbon dioxide is brought into contact with the organic amine composite absorbent for carbon capture according to any one of claims 1 to 6.

8. The method for removing carbon dioxide from flue gas according to claim 7, characterized in that: The contact mode is countercurrent contact, the volume concentration of carbon dioxide in the flue gas containing carbon dioxide ranges from 10% to 30%, and the gas-liquid ratio is 250 to 350 Nm 3 / m 3 .

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