A mixed organic amine absorbent, its preparation method and application

Abstract

The present application relates to a kind of mixed organic amine absorbent and its preparation method and application, and the mixed organic amine absorbent includes main absorbent, absorption promoter and regulator;The mass ratio of the main absorbent, the absorption promoter and the regulator is (0.3-3.4) :(0.5-2.7) :1;The main absorbent is triethylene tetramine, the absorption promoter is N-methyl diethanolamine, and the regulator is 2-amino-2-methyl-1-propanol.The present application can give full play to the synergistic effect of different kinds of organic amine by the compounding of ternary organic amine and the regulation of the ratio between different organic amine, so that the absorption and loading performance of mixed organic amine absorbent is stronger, the cycle capacity is high, the regeneration energy consumption is lower and the kinetic performance is better.

Description

Technical Field

[0001] This invention relates to the field of absorbent technology, specifically to a mixed organic amine absorbent, its preparation method, and its application. Background Technology

[0002] With the continuous warming of the climate, the emission of the greenhouse gas carbon dioxide has become a major concern. Carbon dioxide capture technology is the main approach, and chemical absorption is one of the effective methods for capturing carbon dioxide. Chemical absorption decarbonization technology is currently one of the most mature and widely used technologies, and its core is the development of highly efficient and stable carbon dioxide absorbents.

[0003] Currently, the absorbents widely used in chemical absorption are aqueous solutions of organic amines, such as monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA), and triethanolamine (TEA). Existing technologies use absorbents whose main components contain only one or two organic amines, typically primary amines or combinations of primary amines with tertiary / sterically hindered amines. Primary / secondary amines react rapidly with CO2, but have a low CO2 absorption load; tertiary amines and sterically hindered amines have higher CO2 absorption loads and produce bicarbonates as reaction products, exhibiting good regeneration performance, but they suffer from a slower CO2 absorption reaction rate. Primary and secondary amines have high heats of absorption, resulting in high regeneration energy requirements; in contrast, tertiary amines have lower heats of absorption and lower regeneration energy consumption.

[0004] Therefore, how to fully utilize the functions of different types of organic amines and develop an absorbent with fast absorption rate and low regeneration energy consumption has become an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a mixed organic amine absorbent, its preparation method and application, which has a fast absorption rate, high cycle capacity and low regeneration energy consumption.

[0006] To achieve the above objectives, a first aspect of the present invention provides a mixed organic amine absorbent comprising a main absorbent, an absorption promoter, and a regulator; wherein the mass ratio of the main absorbent, the absorption promoter, and the regulator is (0.3-3.4):(0.5-2.7):1; wherein the main absorbent is triethylenetetramine, the absorption promoter is N-methyldiethanolamine, and the regulator is 2-amino-2-methyl-1-propanol.

[0007] Optionally, the mass ratio of the main absorbent, the absorption promoter, and the regulator is preferably (0.4-3.3):(0.6-2.6):1.

[0008] Optionally, the mixed organic amine absorbent further includes water, wherein the total mass concentration of the main absorbent, the absorption promoter, and the regulator in the mixed organic amine absorbent is 30-40%.

[0009] Optionally, the absorption temperature of the mixed organic amine absorbent is 30-60°C.

[0010] Optionally, the regeneration temperature of the mixed organic amine absorbent is 110-140°C.

[0011] Optionally, the mixed organic amine absorbent has an absorption load of 0.65-0.78 mol / mol and a regeneration efficiency of 68.12-82.05%.

[0012] Optionally, the circulation capacity of the mixed organic amine absorbent is 1.30-1.88 mol / kg.

[0013] A second aspect of the present invention provides a method for preparing a mixed organic amine absorbent, the method comprising:

[0014] The main absorbent, absorption promoter, and regulator are mixed and stirred for the first time to obtain a mixed solution; the mixed solution is placed in a cold water bath and water is added for the second stirring.

[0015] The mass ratio of the main absorbent, the absorption promoter, and the regulator is (0.3-3.4):(0.5-2.7):1; the main absorbent is triethylenetetramine, the absorption promoter is N-methyldiethanolamine, and the regulator is 2-amino-2-methyl-1-propanol.

[0016] Optionally, the first stirring speed is 400-800 r / min and the time is 10-20 min; the second stirring speed is 300-600 r / min and the time is 5-10 min; the cold water bath temperature is 15-20℃.

[0017] The third aspect of the present invention provides the application of the mixed organic amine absorbent provided in the first aspect of the present invention in carbon dioxide capture.

[0018] Through the above technical solution, this invention uses triethylenetetramine as the main absorbent, N-methyldiethanolamine as the absorption promoter, and 2-amino-2-methyl-1-propanol as the regulator to form a ternary mixed organic amine absorbent. By compounding the ternary organic amines and controlling the ratio between different organic amines, the synergistic effect of different types of organic amines can be fully utilized, resulting in a mixed organic amine absorbent with strong absorption and loading performance, high cycle capacity, low regeneration energy consumption, and good kinetic performance.

[0019] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0020] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0021] The first aspect of the present invention provides a mixed organic amine absorbent, which includes a main absorbent, an absorption promoter, and a regulator; the mass ratio of the main absorbent, the absorption promoter, and the regulator is (0.3-3.4):(0.5-2.7):1; the main absorbent is triethylenetetramine, the absorption promoter is N-methyldiethanolamine, and the regulator is 2-amino-2-methyl-1-propanol.

[0022] The synergistic mechanism of the three organic amines in this invention is as follows: Triethylenetetramine (TETA) has a polyamine structure containing two primary and two secondary amino groups, all of which can react with CO2, giving TETA a high absorption capacity and a fast reaction rate. However, the carbamates formed after CO2 absorption by the single primary / secondary amines are stable, resulting in low regeneration efficiency. N-Methyldiethanolamine (MDEA), on the other hand, has a tertiary amine structure, and its CO2 absorption product is bicarbonate, exhibiting good regeneration performance and the ability to replace some water, thus reducing the latent heat of regeneration. Mixing TETA and MDEA can achieve a synergistic effect, combining the high CO2 absorption rate of the primary / secondary amines with the high CO2 absorption load and excellent regeneration performance of the tertiary amine, compensating for the shortcomings of single components and thereby improving the CO2 capture performance of the absorption system. Building upon this foundation, 2-amino-2-methyl-1-propanol (AMP), possessing a sterically hindered amine structure, is added. Its low molecular planarity and strong steric hindrance disrupt intermolecular hydrogen bonds, thus preventing the self-polymerization of urethane esters generated during CO2 absorption by TETA, which leads to difficult product decomposition and regeneration. This further promotes product decomposition, improves regeneration efficiency, and ultimately forms a ternary mixed organic amine absorbent. The mixed organic amine absorbent formed through the compounding of ternary organic amines fully leverages the synergistic effects of different types of organic amines, resulting in a mixed organic amine absorbent with strong absorption and loading performance, high cycle capacity, low regeneration energy consumption, and good kinetic performance.

[0023] According to the present invention, optionally, the mass ratio of the main absorbent, the absorption promoter, and the regulator is (0.4-3.3):(0.6-2.6):1. Through the above preferred embodiments, the proportions of the main absorbent, the absorption promoter, and the regulator within the above range can fully leverage the synergistic effect of the three, resulting in a mixed organic amine absorbent with a fast absorption rate, high circulation capacity, and low regeneration energy consumption.

[0024] According to the present invention, optionally, the mixed organic amine absorbent further includes water, wherein the total mass concentration of the main absorbent, the absorption promoter, and the regulator in the mixed organic amine absorbent is 30-40%. Through the above embodiments, the mixed organic amine absorbent exhibits good absorption and regeneration performance.

[0025] According to the present invention, optionally, the absorption temperature of the mixed organic amine absorbent is 30-60°C. Within the above temperature range, the absorbent can achieve an absorption load of 0.65-0.78 mol / mol.

[0026] According to the present invention, optionally, the regeneration temperature of the mixed organic amine absorbent is 110-140°C. Within the above temperature range, the absorbent can achieve a regeneration efficiency of 68.12-82.05%.

[0027] According to the present invention, optionally, the absorption load of the mixed organic amine absorbent is 0.65-0.78 mol / mol, and the regeneration efficiency is 68.12-82.05%.

[0028] According to the present invention, optionally, the circulation capacity of the mixed organic amine absorbent is 1.30-1.88 mol / kg.

[0029] A second aspect of the present invention provides a method for preparing a mixed organic amine absorbent, the method comprising:

[0030] The main absorbent, absorption promoter, and regulator are mixed and stirred for the first time to obtain a mixed solution; the mixed solution is placed in a cold water bath and water is added for the second stirring.

[0031] The mass ratio of the main absorbent, the absorption promoter, and the regulator is (0.3-3.4):(0.5-2.7):1; the main absorbent is triethylenetetramine, the absorption promoter is N-methyldiethanolamine, and the regulator is 2-amino-2-methyl-1-propanol.

[0032] According to the present invention, optionally, the first stirring speed is 400-800 r / min and the time is 10-20 min; the second stirring speed is 300-600 r / min and the time is 5-10 min; the cold water bath temperature is 15-20℃.

[0033] A third aspect of this invention provides the application of the mixed organic amine absorbent provided in the first aspect of this invention in carbon dioxide capture. The conditions for the mixed organic amine absorbent of this invention to absorb carbon dioxide include: a temperature of 30-60°C and a pressure of 0.05-0.25 MPa.

[0034] The present invention will be further illustrated by the following examples, but the present invention is not limited thereto.

[0035] Example 1

[0036] 8.33 g of triethylenetetramine, 5.10 g of N-methyldiethanolamine, and 7.04 g of 2-amino-2-methyl-1-propanol were mixed and stirred for the first time to obtain a mixed solution. The mixed solution was then placed in a 20°C cold water bath, and 60 g of water was added for the second stirring to obtain a mixed organic amine absorbent. The first stirring speed was 600 r / min for 15 min; the second stirring speed was 500 r / min for 8 min.

[0037] Example 2

[0038] 27.37 g of triethylenetetramine, 14.60 g of N-methyldiethanolamine, and 18.25 g of 2-amino-2-methyl-1-propanol were mixed and stirred for the first time to obtain a mixed solution. The mixed solution was then placed in a 20°C cold water bath and 100 g of water was added for the second stirring to obtain a mixed organic amine absorbent. The first stirring speed was 600 r / min for 15 min, and the second stirring speed was 500 r / min for 8 min.

[0039] Example 3

[0040] 34.02 g of triethylenetetramine, 18.88 g of N-methyldiethanolamine, and 27.53 g of 2-amino-2-methyl-1-propanol were mixed and stirred for the first time to obtain a mixed solution. The mixed solution was then placed in a 20°C cold water bath and 120 g of water was added for the second stirring to obtain a mixed organic amine absorbent. The first stirring speed was 600 r / min for 15 min, and the second stirring speed was 500 r / min for 8 min.

[0041] Comparative Example 1

[0042] 10.36 g of triethylenetetramine, 19.36 g of N-methyldiethanolamine, and 2.89 g of 2-amino-2-methyl-1-propanol were mixed and stirred for the first time to obtain a mixed solution. The mixed solution was then placed in a 20°C cold water bath and 60-120 g of water was added for the second stirring to obtain a mixed organic amine absorbent. The first stirring speed was 600 r / min for 15 min; the second stirring speed was 500 r / min for 8 min.

[0043] Comparative Example 2

[0044] 33.86 g of triethylenetetramine and 18.71 g of N-methyldiethanolamine were mixed and stirred for the first time to obtain a mixed solution. The mixed solution was then placed in a 20°C cold water bath and 120 g of water was added for the second stirring to obtain a mixed organic amine absorbent. The first stirring speed was 600 r / min for 15 min, and the second stirring speed was 500 r / min for 8 min.

[0045] Test case

[0046] Absorption process of absorbent: The mixed organic amine absorbents prepared in Examples 1-3 and Comparative Examples 1-2 were placed at 0.05-0.25 MPa, 30-60℃, and simulated flue gas concentration of 6-20% to absorb CO2.

[0047] Absorbent regeneration process: After the absorption reaction is completed, the mixed organic amine absorbent is placed in a stirring speed of 300-1000 rpm and an oil bath temperature of 110-140℃ to desorb CO2.

[0048] The circulation capacity, absorption load, and regeneration efficiency of the mixed organic amine absorbents prepared in Examples 1-3 and Comparative Examples 1-2 were determined and calculated, and the results are shown in Table 1.

[0049] Circulation capacity: The difference between the amount of CO2 (mol) absorbed by a unit mass of amine (kg) in the rich solution and the amount of CO2 (mol) enriched by a unit mass of amine (kg) in the lean solution after desorption.

[0050] Absorption load: The amount of CO2 absorbed per unit absorbent (mol / mol).

[0051] Regeneration efficiency: The ratio (%) of the absorption load of CO2 reabsorbed by the lean solution after desorption to the absorption load of the fresh absorbent.

[0052] Table 1

[0053]

[0054] As can be seen from Table 1, the mixed organic amine absorbents prepared in Examples 1-3 of the present invention have higher cycle capacity, absorption load and regeneration efficiency compared with Comparative Examples 1-2, and can better improve the absorption rate and regeneration rate of the absorbent, and reduce the regeneration energy consumption of the absorbent.

[0055] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0056] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0057] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A mixed organic amine absorbent, characterized by, The mixed organic amine absorbent comprises a main absorbent, an absorption promoter and a regulator; the mass ratio of the main absorbent, the absorption promoter and the regulator is (0.3-3.4):(0.5-2.7):1; The main absorbent is triethylenetetramine, the absorption promoter is N-methyldiethanolamine, and the regulator is 2-amino-2-methyl-1-propanol. The absorption load of the mixed organic amine absorbent is 0.65-0.78 mol / mol, and the regeneration efficiency is 68.12-82.05%; the cycle capacity of the mixed organic amine absorbent is 1.30-1.88 mol / kg.

2. The mixed organic amine absorbent according to claim 1, wherein, The mass ratio of the main absorbent, the absorption promoter and the regulator is (0.4-3.3):(0.6-2.6):

1.

3. The mixed organic amine absorbent of claim 1, wherein, The mixed organic amine absorbent further comprises water, and the total mass concentration of the main absorbent, the absorption promoter and the regulator in the mixed organic amine absorbent is 30-40%.

4. The mixed organic amine absorbent of claim 1, wherein, The absorption temperature of the mixed organic amine absorbent is 30-60℃.

5. The mixed organic amine absorbent of claim 1, wherein, The regeneration temperature of the mixed organic amine absorbent is 110-140℃.

6. A method of preparing the mixed organic amine absorbent according to any one of claims 1 to 5, characterized in that, The method comprises: The main absorbent, the absorption promoter and the regulator are mixed for first stirring to obtain a mixed solution; the mixed solution is placed in a cold water bath and water is added for second stirring; the temperature of the cold water bath is 15-20℃; The mass ratio of the main absorbent, the absorption promoter and the regulator is (0.3-3.4):(0.5-2.7):1; the main absorbent is triethylenetetramine, the absorption promoter is N-methyldiethanolamine, and the regulator is 2-amino-2-methyl-1-propanol.

7. The method of claim 6, wherein, The first stirring speed is 400-800 r / min, and the time is 10-20 min; The second stirring speed is 300-600 r / min, and the time is 5-10 min.

8. Use of the mixed organic amine absorbent in any one of claims 1-5 in carbon dioxide capture.

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