Mixed organic amine absorbent as well as preparation method and application thereof

Abstract

The invention relates to a mixed organic amine absorbent as well as a preparation method and application thereof. The mixed organic amine absorbent comprises a main absorbent, an absorption enhancer and a regulator, the mass ratio of the main absorbent to the absorption enhancer to the conditioning agent is (0.3-3.4): (0.5-2.7): 1; the main absorbent is triethylene tetramine, the absorption enhancer is N-methyldiethanolamine, and the conditioning agent is 2-amino-2-methyl-1-propanol. By compounding the ternary organic amines and regulating and controlling the proportion of different organic amines, the synergistic effect of different types of organic amines can be fully exerted, so that the mixed organic amine absorbent has relatively strong absorption and loading performance, high cycle capacity, relatively low regeneration energy consumption and relatively good dynamic performance.

Description

Technical Field

[0001] The present invention relates to the technical field of absorbents, in particular to a mixed organic amine absorbent and a preparation method and application thereof. Background Art

[0002] As the climate continues to warm, greenhouse gas carbon dioxide emissions have become a major concern. Carbon dioxide capture technology is a primary approach, with chemical absorption being one of the most effective methods. Chemical absorption decarbonization is currently one of the most mature and widely used technologies, with the core focus being 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, represented by organic amines such as monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA), and triethanolamine (TEA). The absorbents used in the prior art primarily contain only one or two organic amines, typically primary amines or a combination of a primary amine and a tertiary or sterically hindered amine. The chemical reaction rate between primary / secondary amines and CO2 is fast, but the CO2 absorption capacity is low. Tertiary and sterically hindered amines have a high CO2 absorption capacity, and the reaction product is bicarbonate, which has good regeneration performance, but they suffer from a slow CO2 absorption reaction rate. Primary and secondary amines have high absorption heat and require high regeneration energy. In contrast, tertiary amines have a lower absorption heat and require less regeneration energy.

[0004] Therefore, how to give full play to the role 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 the present invention is to provide a mixed organic amine absorbent and a preparation method and application thereof. The absorbent has a fast absorption rate, a high circulation capacity and a low regeneration energy consumption.

[0006] In order to achieve the above-mentioned object, 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.

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

[0008] Optionally, the mixed organic amine absorbent further comprises water, and in the mixed organic amine absorbent, the total mass concentration of the main absorbent, the absorption promoter and the regulator 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 absorption load of the mixed organic amine absorbent is 0.65-0.78 mol / mol, and the regeneration efficiency is 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: The main absorbent, the absorption enhancer and the regulator are mixed and stirred for a first time to obtain a mixed solution; the mixed solution is placed in a cold water bath and water is added to perform a second stirring; 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.

[0014] 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; and the temperature of the cold water bath is 15-20°C.

[0015] The third aspect of the present invention provides use of the mixed organic amine absorbent provided by the first aspect of the present invention in carbon dioxide capture.

[0016] Through the above technical solution, the present invention utilizes triethylenetetramine as the primary absorbent, N-methyldiethanolamine as the absorption enhancer, and 2-amino-2-methyl-1-propanol as the modifier to form a ternary mixed organic amine absorbent. By compounding the ternary organic amines and regulating the ratios of the different organic amines, the synergistic effects of the different organic amines can be fully utilized, resulting in the mixed organic amine absorbent having strong absorption and loading performance, high circulation capacity, low regeneration energy consumption, and excellent kinetic performance.

[0017] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0018] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0019] A 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.

[0020] The synergistic mechanism of the three organic amines in this invention is as follows: triethylenetetramine (TETA) has a polyamino structure, containing two primary and two secondary amino groups in its chemical structure. Both react with CO2, giving TETA a high absorption capacity and a fast reaction rate. However, the carbamates produced by single primary / secondary amines after CO2 absorption are stable and have low regeneration efficiency. N-methyldiethanolamine (MDEA), on the other hand, has a tertiary amine structure and produces bicarbonate after CO2 absorption, which has excellent regeneration performance, can partially displace water, and reduce the latent heat of regeneration. The combination of TETA and MDEA can exert a synergistic effect, combining the efficient CO2 absorption rate of primary / secondary amines with the high CO2 absorption capacity and excellent regeneration performance of tertiary amines, compensating for the shortcomings of the individual components and thereby improving the CO2 capture performance of the absorption system. On this basis, 2-amino-2-methyl-1-propanol (AMP), a sterically hindered amine, was added to block intermolecular hydrogen bonds using its low molecular planarity and strong steric hindrance. This prevents the self-polymerization of carbamates generated by TETA absorbing CO2, which results in difficult product decomposition and regeneration. This further promotes product decomposition and improves regeneration efficiency, ultimately forming a ternary mixed organic amine absorbent. This hybrid organic amine absorbent, formed by compounding ternary organic amines, fully leverages the synergistic effects of different organic amine types, resulting in a hybrid organic amine absorbent with strong absorption and loading performance, high cycle capacity, low regeneration energy consumption, and excellent kinetic performance.

[0021] According to the present invention, optionally, the mass ratio of the main absorbent, the absorption enhancer, and the regulator is preferably (0.4-3.3):(0.6-2.6):1. Through the above preferred embodiment, when the ratio of the main absorbent, the absorption enhancer, and the regulator is within the above range, the synergistic effect of the three can be fully utilized, resulting in a fast absorption rate, high circulation capacity, and low regeneration energy consumption for the mixed organic amine absorbent.

[0022] According to the present invention, optionally, the mixed organic amine absorbent further comprises water, and in the mixed organic amine absorbent, the total mass concentration of the main absorbent, the absorption promoter, and the regulator is 30-40%. Through the above embodiment, the mixed organic amine absorbent has good absorption and regeneration performance.

[0023] 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.

[0024] 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%.

[0025] 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%.

[0026] According to the present invention, optionally, the circulation capacity of the mixed organic amine absorbent is 1.30-1.88 mol / kg.

[0027] A second aspect of the present invention provides a method for preparing a mixed organic amine absorbent, the method comprising: The main absorbent, the absorption enhancer and the regulator are mixed and stirred for a first time to obtain a mixed solution; the mixed solution is placed in a cold water bath and water is added to perform a second stirring; 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.

[0028] 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; and the cold water bath temperature is 15-20°C.

[0029] The third aspect of the present invention provides the use of the mixed organic amine absorbent provided in the first aspect of the present invention in carbon dioxide capture. The conditions for the mixed organic amine absorbent of the present invention to absorb carbon dioxide include: temperature of 30-60°C and pressure of 0.05-0.25 MPa.

[0030] The present invention is further illustrated below by way of examples, but the present invention is not limited thereto.

[0031] Example 1 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 a 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 a second stirring time to obtain a mixed organic amine absorbent. The first stirring speed was 600 r / min for 15 minutes, and the second stirring speed was 500 r / min for 8 minutes.

[0032] Example 2 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 a 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 a second time to obtain a mixed organic amine absorbent. The first stirring speed was 600 r / min for 15 minutes, and the second stirring speed was 500 r / min for 8 minutes.

[0033] Example 3 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 a 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 a second time to obtain a mixed organic amine absorbent. The first stirring speed was 600 r / min for 15 minutes, and the second stirring speed was 500 r / min for 8 minutes.

[0034] Comparative Example 1 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 a 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 a second time to obtain a mixed organic amine absorbent. The first stirring speed was 600 r / min for 15 minutes, and the second stirring speed was 500 r / min for 8 minutes.

[0035] Comparative Example 2 33.86 g of triethylenetetramine and 18.71 g of N-methyldiethanolamine were mixed and stirred for a 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 a second time to obtain a mixed organic amine absorbent. The first stirring speed was 600 r / min for 15 minutes, and the second stirring speed was 500 r / min for 8 minutes.

[0036] Test Case Absorbent absorption process: The mixed organic amine absorbents prepared in Examples 1-3 and Comparative Examples 1-2 were placed under 0.05-0.25 MPa, 30-60° C., and a simulated flue gas concentration of 6-20% to absorb CO 2 .

[0037] Absorbent regeneration process: After the absorption reaction is completed, the mixed organic amine absorbent is placed at a stirring speed of 300-1000 rpm and an oil bath temperature of 110-140°C to desorb CO2.

[0038] 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 measured and calculated. The results are shown in Table 1.

[0039] Circulation capacity: the difference between the amount of CO2 absorbed (mol) by unit mass of amine (kg) in the rich liquid and the amount of CO2 enriched (mol) by unit mass of amine (kg) in the lean liquid after desorption.

[0040] Absorption load: the amount of CO2 absorbed by a unit absorbent (mol / mol).

[0041] Regeneration efficiency: the ratio (in %) of the absorption load of CO2 absorbed by the lean liquid after desorption to the absorption load of the fresh absorbent.

[0042] Table 1

[0043] As can be seen from Table 1, the mixed organic amine absorbents prepared in Examples 1-3 of the present invention have higher circulation capacity, absorption load and regeneration efficiency than those in Comparative Examples 1-2, can further improve the absorption rate and regeneration rate of the absorbent, and reduce the regeneration energy consumption of the absorbent.

[0044] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within 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 scope of protection of the present invention.

[0045] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0046] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A mixed organic amine absorbent, characterized in that: 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.

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

1.

3. The mixed organic amine absorbent according to claim 1, wherein: The mixed organic amine absorbent also includes water. In the mixed organic amine absorbent, the total mass concentration of the main absorbent, the absorption promoter and the regulator is 30-40%.

4. The mixed organic amine absorbent according to claim 1, wherein: The absorption temperature of the mixed organic amine absorbent is 30-60°C.

5. The mixed organic amine absorbent according to claim 1, wherein: The regeneration temperature of the mixed organic amine absorbent is 110-140°C.

6. The mixed organic amine absorbent according to claim 1, wherein: 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%.

7. The mixed organic amine absorbent according to claim 1, wherein: The circulation capacity of the mixed organic amine absorbent is 1.30-1.88 mol / kg.

8. A method for preparing a mixed organic amine absorbent, characterized in that: The method includes: The main absorbent, the absorption enhancer and the 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 to perform a second stirring; 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.

9. The method according to claim 8, wherein: The first stirring speed is 400-800 r / min, and the time is 10-20 min; The second stirring speed is 300-600r / min, and the time is 5-10min; The temperature of the cold water bath is 15-20°C.

10. Use of the mixed organic amine absorbent according to any one of claims 1 to 7 in carbon dioxide capture.

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