阅读说明：本技术 一种二氧化碳的无水相变吸收剂及其吸收和再生方法 (Anhydrous phase change absorbent for carbon dioxide and absorption and regeneration method thereof ) 是由 张立麒 江伍凤 李小姗 罗聪 邬凡 高歌 于 2021-08-20 设计创作，主要内容包括：本发明特别涉及一种二氧化碳的无水相变吸收剂及其吸收和再生方法,属于二氧化碳捕集技术领域,吸收剂包括：四甲基铵甘氨酸和醇；以功能型离子液体——四甲基铵甘氨酸([N-(1111)][Gly])为主吸收剂,以醇为溶剂,同时醇也作为分相剂,相变吸收剂在吸收CO-(2)后生成沉淀,且易分层,大部分二氧化碳产物集中在下层沉淀中,即富相中。解吸时,只需对富相进行加热,可降低加热的溶液量,有效降低再生能耗。醇的加入显著降低[N-(1111)][Gly]的粘度,同时参与反应,提高了理论吸收容量,另外沉淀的生成促进吸收反应正向进行,进一步促进吸收进行。(The invention particularly relates to an anhydrous phase change absorbent for carbon dioxide and an absorption and regeneration method thereof, belonging to the technical field of carbon dioxide capture, wherein the absorbent comprises: tetramethylammonium glycine and alcohol; using functional ionic liquid-tetramethyl ammonium glycine ([ N ] 1111 ][Gly]) The phase-change absorbent is used for absorbing CO, and takes alcohol as a solvent and simultaneously takes alcohol as a phase-splitting agent 2 Then, a precipitate is generated, and the precipitate is easy to separate, and most of the carbon dioxide product is concentrated in the lower precipitate, namely a rich phase. During desorption, only the rich phase needs to be heated, so that the amount of heated solution can be reduced, and the regeneration energy consumption is effectively reduced. Significant reduction in alcohol addition [ N ] 1111 ][Gly]The viscosity of (2) and the reaction are simultaneously participated in, the theoretical absorption capacity is improved, and in addition, the generation of the precipitate promotes the forward progress of the absorption reaction, further promotes the forward progress of the absorption reactionAbsorption proceeds.)

1. An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and alcohol.

2. The anhydrous phase change absorbent for carbon dioxide according to claim 1, wherein the mass ratio of the tetramethylammonium glycine to the alcohol is 1: 4-2: 1.

3. the anhydrous phase change absorbent for carbon dioxide according to claim 1, wherein the mass fraction of tetramethylammonium glycine is 20% to 67%.

4. The anhydrous phase change absorbent for carbon dioxide according to claim 1, wherein the alcohol comprises at least one of a C1-C5 alcohol.

5. The anhydrous phase change absorbent for carbon dioxide according to claim 4, wherein the alcohol comprises at least one of ethanol, n-propanol, and n-butanol.

6. The anhydrous phase change absorbent for carbon dioxide according to claim 1, wherein the purity of the alcohol is analytical grade.

7. A method of absorbing carbon dioxide, the method comprising: subjecting a carbon dioxide-containing gas and an anhydrous phase change absorbent for carbon dioxide according to any one of claims 1 to 6 to absorption by contact to obtain an absorbent with precipitates.

8. The absorption process according to claim 7, wherein the temperature of the contact absorption is from 30 ℃ to 60 ℃.

9. A method for regenerating an anhydrous phase change absorbent for carbon dioxide according to any one of claims 1 to 6, characterized in that it comprises:

obtaining an absorbent with sediment after absorbing carbon dioxide;

separating the absorbent with the precipitate to obtain a phase-rich precipitate and a liquid phase;

desorbing the phase-rich precipitate to obtain a desorbed substance;

mixing the desorbent and the liquid phase to complete regeneration.

10. The method for regenerating the anhydrous phase-change absorbent for carbon dioxide as claimed in claim 9, wherein the desorption is performed by heating at a temperature of 118 ℃ to 122 ℃.

Technical Field

The invention belongs to the technical field of carbon dioxide capture, and particularly relates to an anhydrous phase change absorbent for carbon dioxide and an absorption and regeneration method thereof.

Background

In recent years, with the growing prominence of the greenhouse effect, the capture, utilization and sequestration of greenhouse gases, particularly carbon dioxide, have received a high degree of attention from the scientific community and governments of various countries. The greenhouse effect is intensified to cause global warming, which causes a series of ecological environmental problems, aggravates regional natural disasters and causes non-negligible influence on human survival and development.

Carbon dioxide is mainly derived from the combustion of fossil fuels and is concentrated in industries such as industry, electric power, transportation and the like. Carbon capture is considered to be an important method for effectively reducing the carbon dioxide content in the atmosphere. Currently, absorption methods, adsorption methods, membrane separation methods, and the like are mainly used for capturing carbon dioxide. Of which solvent absorption is most commonly used.

In the process of capturing carbon dioxide by solvent absorption, a physical absorption method and a chemical absorption method can be classified according to whether carbon dioxide chemically reacts with a solvent. The physical method is based on the solubility difference of the absorbent to carbon dioxide and other gas components, carbon dioxide is absorbed from mixed gas under pressure, and the absorbed carbon dioxide is released through reduced pressure flash evaporation and stripping, so that the carbon dioxide is separated from other gases, and the carbon dioxide is concentrated. The chemical method is that the absorbent and the carbon dioxide can perform chemical reaction to generate rich liquid rich in the carbon dioxide, the rich liquid can desorb the carbon dioxide under the heating action, the carbon dioxide and other gas components are separated, the absorbent desorbing the carbon dioxide can be used for the absorption process of the carbon dioxide again, and the absorption and desorption processes are alternately performed, so that the separation and concentration of the carbon dioxide and other gases are realized.

The absorbents commonly used in carbon capture absorbents today are alcamines. The traditional organic amine aqueous solution has high energy consumption for regeneration and water pollution caused by subsequent treatment by a water phase change absorbent.

Disclosure of Invention

The application aims to provide an anhydrous phase change absorbent for carbon dioxide and an absorption and regeneration method thereof, so as to solve the defects that the conventional organic amine aqueous solution is high in regeneration energy consumption and the conventional aqueous phase change absorbent is used for subsequent treatment of water pollution.

The embodiment of the invention provides an anhydrous phase change absorbent for carbon dioxide, which comprises: tetramethylammonium glycine and alcohol.

Optionally, the mass ratio of the tetramethylammonium glycine to the alcohol is 1: 4-2: 1.

optionally, the mass fraction of the tetramethylammonium glycine is 20% to 67%.

Optionally, the alcohol comprises at least one of a C1-C5 alcohol.

Optionally, the alcohol comprises at least one of ethanol, n-propanol, and n-butanol.

Optionally, the alcohol is analytically pure.

Based on the same inventive concept, the embodiment of the invention also provides a method for absorbing carbon dioxide, which comprises the following steps: the gas containing carbon dioxide and the anhydrous phase change absorbent of carbon dioxide are contacted and absorbed to obtain the absorbent with sediment.

Optionally, the temperature of the contact absorption is 30-60 ℃, wherein the preferred contact absorption temperature is 30 ℃.

Based on the same inventive concept, the embodiment of the invention also provides a regeneration method of the anhydrous phase change absorbent for carbon dioxide, which comprises the following steps:

obtaining an absorbent with sediment after absorbing carbon dioxide;

separating the absorbent with the precipitate to obtain a phase-rich precipitate and a liquid phase;

desorbing the phase-rich precipitate to obtain a desorbed substance;

mixing the desorbent and the liquid phase to complete regeneration.

Optionally, the desorption mode is heating, and the heating temperature of the heating is 118-122 ℃.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

the embodiment of the invention provides an anhydrous phase change absorbent for carbon dioxide, which comprises: tetramethylammonium glycine and alcohol; using functional ionic liquid-tetramethyl ammonium glycine ([ N ]₁₁₁₁][Gly]) The phase-change absorbent is used for absorbing CO, and takes alcohol as a solvent and simultaneously takes alcohol as a phase-splitting agent₂Then, a precipitate is generated, and the precipitate is easy to separate, and most of the carbon dioxide product is concentrated in the lower precipitate, namely a rich phase. During desorption, only the rich phase needs to be heated, so that the amount of heated solution can be reduced, and the regeneration energy consumption is effectively reduced. Significant reduction in alcohol addition [ N ]₁₁₁₁][Gly]The viscosity of (2) and the reaction are simultaneously involved, so that the theoretical absorption capacity is improved, and in addition, the formation of the precipitate promotes the forward progress of the absorption reaction, so that the absorption progress is further promoted.

The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a flow chart of a regeneration method provided by an embodiment of the present invention;

FIG. 2 is a graph of the absorption performance of the absorbents provided in examples 1 to 5 of the present invention;

FIG. 3 is a graph of the absorption performance of the absorbents provided in examples 6 to 10 of the present invention;

fig. 4 is a combined comparison diagram of fig. 2 and fig. 3.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.

Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

In order to solve the technical problems, the general idea of the embodiment of the application is as follows:

according to an exemplary embodiment of the present invention, there is provided an anhydrous phase change absorbent for carbon dioxide, the absorbent including: tetramethylammonium glycine and alcohol. As will be appreciated by those skilled in the art: anhydrous does not mean absolutely anhydrous, but rather the incorporation of water in the absorbent is avoided as far as possible.

The structural formula of tetramethylammonium glycine is:meanwhile, the tetramethylammonium glycine can be prepared by a one-step synthesis method through acid-base neutralization reaction.

As an alternative embodiment, the mass ratio of tetramethylammonium glycine to the alcohol is 1: 4-2: 1.

controlling the mass ratio of the tetramethylammonium glycine to the alcohol to be 1: 4-2: the reason for 1 is that the mixed absorbent in this ratio has good CO₂The absorption performance and the layering effect, and the adverse effect of the mass ratio being too small is that the absorbent has an adverse effect on CO₂Has a low saturated absorption amount, and has an excessive adverse effect of saturated absorption of CO₂Has poor stratification effect and is not beneficial to poor-rich phase separation。

As an alternative embodiment, the alcohol is at least one of C1-C5 alcohols, and specifically, may be at least one of ethanol, n-propanol, and n-butanol. Preferably, the alcohol is ethanol or n-propanol.

Alcohol is used as a solvent and also used as a phase separation agent; significant reduction in alcohol addition [ N ]₁₁₁₁][Gly]The viscosity of the adsorbent is reduced, the absorption mass transfer process is facilitated, the mass transfer speed is increased, the absorption rate is higher, in addition, the loss of the absorbent in a pipeline can be reduced due to the low viscosity, meanwhile, the alcohol participates in the reaction, and the theoretical absorption capacity is improved.

According to another exemplary embodiment of the present invention, there is provided a method for absorbing carbon dioxide, the method including: the gas containing carbon dioxide and the anhydrous phase change absorbent of carbon dioxide provided above are contacted and absorbed to obtain the absorbent with precipitate.

As an alternative embodiment, the contact absorption temperature is from 30 ℃ to 60 ℃, preferably the contact temperature is 30 ℃.

According to another exemplary embodiment of the present invention, there is provided a method of regenerating the anhydrous phase change absorbent for carbon dioxide as provided above, the method including:

s1, obtaining an absorbent with sediment after absorbing carbon dioxide;

s2, separating the absorbent with the precipitate to obtain a rich-phase precipitate and a liquid phase;

s3, desorbing the rich-phase precipitate to obtain a desorbed substance;

and S4, mixing the desorbed substances with the liquid phase to complete regeneration.

Because the anhydrous phase change absorbent absorbs CO₂Then, a precipitate is generated, and the precipitate is easy to separate, and most of the carbon dioxide product is concentrated in the lower precipitate, namely a rich phase. During desorption, only the rich phase needs to be heated, so that the amount of heated solution can be reduced, and the regeneration energy consumption is effectively reduced; the heating temperature is 118-122 ℃.

The anhydrous phase change absorbent for carbon dioxide and the method for absorbing and regenerating the same according to the present application will be described in detail with reference to examples, comparative examples, and experimental data.

It should be noted that the tetramethylammonium glycine used in the following examples and comparative examples was prepared by the applicant, and the specific preparation method is as follows:

(1) reacting tetramethylammonium hydroxide anhydride [ N₁₁₁₁][OH]·5H₂O and glycine Gly in a molar ratio of 1: 1.02 (glycine is slightly excessive to ensure sufficient reaction), adding a proper amount of deionized water for dissolution, lightly putting magnetons with proper sizes into the beaker, and sealing the mouth of the beaker by using a preservative film. And (3) switching on a constant-temperature magneton stirrer (water bath) to a power supply, setting the temperature to be 25 ℃, preheating for 5 minutes, placing the beaker in the beaker, setting the magneton rotating speed to be 10r/s, fully reacting for 24 hours, and turning off the power supply after the reaction is finished. The reaction equation is as follows:

[N₁₁₁₁][OH]·5H₂O+Gly→[N₁₁₁₁][Gly]+6H₂O

(2) transferring the reacted product into a flask, connecting the flask with an anti-bumping pipe, connecting the flask with a rotary evaporator, closing an exhaust valve, connecting the rotary evaporator and a circulating water vacuum pump power supply, turning on a circulating water switch, continuously vacuumizing to ensure that the interior of the flask is negative pressure, setting the evaporation temperature to be 55 ℃ at the beginning, ensuring that the flask can be properly raised after no bumping phenomenon exists, and closing the power supply and a circulating water faucet after the rotary evaporation is finished. After most of the solvent is removed, the flask is put into a vacuum drying oven, the temperature is set to be 60 ℃, and the flask is dried to constant weight to obtain [ N ]₁₁₁₁][Gly]Crude product of ionic liquid.

(3) Ionic liquid [ N ]₁₁₁₁][Gly]Dissolving in ethanol and glycine is insoluble in ethanol, adding anhydrous ethanol three times of the crude product into the flask, stirring, washing, filtering to remove glycine to obtain [ N ]₁₁₁₁][Gly]The ethanol solution is connected to a rotary evaporator, the initial evaporation temperature is 45 ℃, and the ethanol solution can be properly raised after no bumping phenomenon is ensured. Removing most ethanol, placing in a vacuum drying oven, setting the temperature at 65 deg.C, and drying to constant weight to obtain target product [ N ]₁₁₁₁][Gly]And (5) ionic liquid, and sealing and storing.

The types of reagents used in the preparation of tetramethylammonium glycine were as follows:

tetramethylammonium hydroxide pentahydrate, molecular weight 181.23, purity 99%, CAS number: 10424-65-4, manufacturer: saen chemical technology (shanghai) ltd.

Glycine, molecular weight 75.07, purity: analytical grade, CAS No.: 56-40-6, manufacturer: chemical agents of the national drug group, ltd.

The following examples and comparative examples used the following alcohol types:

absolute ethanol, molecular weight 46.07, purity: analytical grade, CAS No.: 64-17-5, manufacturer: chemical agents of the national drug group, ltd.

N-propanol, molecular weight 60.10, purity: analytical grade, CAS No.: 71-23-8, manufacturer: chemical agents of the national drug group, ltd.

Example 1

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and ethanol; the mass ratio of the tetramethylammonium glycine to the ethanol is 2: 1.

example 2

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and ethanol; the mass ratio of the tetramethylammonium glycine to the ethanol is 1: 1.

example 3

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and ethanol; the mass ratio of the tetramethylammonium glycine to the ethanol is 1: 2.

example 4

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and ethanol; the mass ratio of the tetramethylammonium glycine to the ethanol is 1: 3.

example 5

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and ethanol; the mass ratio of the tetramethylammonium glycine to the ethanol is 1: 4.

example 6

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and n-propanol; the mass ratio of the tetramethylammonium glycine to the n-propanol is 2: 1.

example 7

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and n-propanol; the mass ratio of the tetramethylammonium glycine to the n-propanol is 1: 1.

example 8

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and n-propanol; the mass ratio of the tetramethylammonium glycine to the n-propanol is 1: 2.

example 9

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and n-propanol; the mass ratio of the tetramethylammonium glycine to the n-propanol is 1: 3.

example 10

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and n-propanol; the mass ratio of the tetramethylammonium glycine to the n-propanol is 1: 4.

comparative example 1

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine.

Comparative example 2

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and ethanol; the mass ratio of the tetramethylammonium glycine to the ethanol is 1: 6.

comparative example 3

An anhydrous phase change absorbent for carbon dioxide, the absorbent comprising: tetramethylammonium glycine and n-propanol; the mass ratio of the tetramethylammonium glycine to the n-propanol is 1: 6.

experimental example:

the absorbents provided in examples 1 to 10 and comparative examples 1 to 4 were subjected to absorption performance tests,

the parameters of the performance test are as follows: the absorption temperature is 30 ℃, the pressure is 0.1MPa, the concentration of carbon dioxide is 99.99 percent, and the dosage of the absorbent is ionic liquid [ N ]₁₁₁₁][Gly]The mass of (2) was fixed to 3g, and the amount of alcohol was in accordance with the ratio.

The test results are shown in fig. 2.

As can be seen from the graph, the addition of alcohol can significantly improve the absorption rate and absorption amount of carbon dioxide by the absorbent by comparing the data of comparative example 1 and example, and the applicant found that the absorption performance is not improved when the ratio of tetramethylammonium glycine to alcohol is out of the range provided by the examples of the present invention by comparing the data of comparative example 2, comparative example 3 and example, and analyzed the reason for this may be: the main absorbent is ionic liquid, and compared with pure ionic liquid, alcohol has certain volatility, so that the proportion of alcohol does not need to be increased when the expected effect is achieved.

One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:

(1) the absorbent provided by the embodiment of the invention absorbs CO₂Then, a precipitate is generated, and the precipitate is easy to separate, and most of the carbon dioxide product is concentrated in the lower precipitate, namely a rich phase. During desorption, only the rich phase needs to be heated, so that the amount of heated solution can be reduced, and the regeneration energy consumption is effectively reduced;

(2) the absorbent provided by the embodiment of the invention is functional ionic liquid-tetramethylammonium glycine ([ N ]₁₁₁₁][Gly]) The main absorbent is alcohol, and the addition of the alcohol obviously reduces [ N ]₁₁₁₁][Gly]The viscosity of the composite material is simultaneously involved in the reaction, so that the theoretical absorption capacity is improved;

(3) in the absorbent provided by the embodiment of the invention, the alcohol is a solvent, and the alcohol is a phase separation agent, so that the generation of the precipitate promotes the forward progress of the absorption reaction, and further promotes the progress of the absorption.

Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.