Absorbent for carbon dioxide capture, and carbon dioxide capturing and absorbing method

Abstract

An absorbent for carbon dioxide capture, and a carbon dioxide capturing and absorbing method. The absorbent comprises, in percentages by mass, 40-70% of a main absorbent, 1-20% of an accelerator, 0.05-1% of a corrosion inhibitor, and 0.1-1% of an antioxidant, with the balance being water. The main absorbent comprises, in percentages by mass, 0-40% of a fatty amine, and 60-100% of an alcohol amine. The accelerator comprises at least one of a salt, a hindered amine and a sulfur-containing organic compound comprising S＝O, wherein the mass ratio of the salt to the hindered amine to the sulfur-containing organic compound is (0-2):(0-4):(0-6). The absorbent has a viscosity of less than or equal to 20 cp. The above formula improves the carbon dioxide capture and absorption capacity and regeneration effect of the absorbent, and can reduce energy for regeneration.

Description

Carbon dioxide capture absorbent and capture absorption method

[0001] The present application claims priority to the Chinese patent application No. 202410418036.5, filed on April 8, 2024, and entitled "Carbon dioxide capture absorbent and capture absorption method", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to a carbon dioxide capture absorbent, in particular to a carbon dioxide capture absorbent and capture absorption method, belonging to the field of carbon dioxide recovery. BACKGROUND

[0003] Carbon dioxide capture and storage technology (CCUS) refers to an industrial process of separating carbon dioxide from a source of emission or directly utilizing or storing it to achieve carbon dioxide emission reduction, including dry and wet methods, wherein the wet method includes chemical absorption method and physical absorption method.

[0004] The chemical absorption method is a process of contacting a source of emission including carbon dioxide with an absorbent to perform a chemical reaction, so that the carbon dioxide is absorbed into a solution, and then the carbon dioxide is desorbed by heating, and the absorbent is regenerated and recycled. The commonly used absorbent generally contains 60-70% water, and a large amount of water vaporization occurs in the absorbent regeneration process, resulting in high regeneration energy consumption. In the existing research, the water content can be reduced by increasing the absorbent concentration, thereby reducing the water evaporation amount and regeneration energy consumption, but the poor absorbent regeneration effect still exists in the poor water absorbent with high absorbent concentration. (1) The absorbent regeneration effect becomes poor after increasing the absorbent concentration; (2) The water evaporation amount is still large, resulting in still high regeneration energy consumption.

[0005] A carbon dioxide absorbent with high carbon dioxide absorption capacity, good regeneration effect and low regeneration energy consumption is relatively lacking. SUMMARY

[0006] The present application provides a carbon dioxide capture absorbent, which has high carbon dioxide absorption treatment capacity, and good regeneration effect and low regeneration energy consumption.

[0007] The present application also provides a carbon dioxide capture absorption method, which utilizes the above-mentioned carbon dioxide capture absorbent to capture and absorb carbon dioxide, has large treatment capacity, and the above-mentioned carbon dioxide capture absorbent has good regeneration effect and low regeneration energy consumption, and has the advantages of environmental friendliness and resource saving.

[0008] The first aspect of the present application provides a carbon dioxide capture absorbent, wherein the carbon dioxide capture absorbent comprises, in terms of mass percentage, 40-70% of a main absorbent, 1-20% of a promoter, 0.05-1% of a corrosion inhibitor, 0.1-1% of an antioxidant, and the balance being water;

[0009] The main absorbent comprises, in terms of mass percentage, 0-40% of a fatty amine and 60-100% of an alcohol amine, the fatty amine comprising at least one of a primary amine, a secondary amine, a tertiary amine and a polyamine, and the alcohol amine comprising at least one of a monohydroxy, a dihydroxy and a trihydroxy.

[0010] The promoter comprises at least one of a salt, a steric amine and a sulfur-containing organic compound comprising S=O, the salt comprising at least one of a quaternary amine salt, an amino acid salt and a citric acid salt, the steric amine comprising at least one of 2-amino-2-methyl-1,3-propanediol, 2-amino-2-methyl-1-propanol and t-butylaminoethoxyethanol, and the sulfur-containing organic compound comprising at least one of dimethyl sulfone, sulfolane and dimethyl sulfoxide, the mass ratio of the salt, the steric amine and the sulfur-containing organic compound being (0-2):(0-4):(0-6).

[0011] The carbon dioxide capture absorbent has a viscosity of ≤20 cp.

[0012] The carbon dioxide capture absorbent as described above, wherein the number of nitrogen atoms in the fatty amine is ≤3 and the number of carbon atoms is ≤6.

[0013] And / or, the number of nitrogen atoms in the alcohol amine is ≤3 and the number of carbon atoms is ≤6.

[0014] The carbon dioxide capture absorbent as described above, wherein the salt comprises an amino acid salt, the steric amine comprises 2-amino-2-methyl-1-propanol, the sulfur-containing organic compound comprises dimethyl sulfone, and the mass ratio of the salt, the steric amine and the sulfur-containing organic compound is 1:2:3.

[0015] The carbon dioxide capture absorbent as described above, wherein the boiling point of the steric amine is >160℃.

[0016] The carbon dioxide capture absorbent as described above, wherein the corrosion inhibitor comprises sodium vanadate, and the mass percentage of the sodium vanadate in the carbon dioxide capture absorbent is 0.05-0.2%.

[0017] The carbon dioxide capture absorbent as described above, wherein the antioxidant comprises potassium sodium tartrate, and the mass percentage of the potassium sodium tartrate in the carbon dioxide capture absorbent is 0.1-0.3%.

[0018] The carbon dioxide capture absorbent as described above, wherein the carbon dioxide removal rate of the carbon dioxide capture absorbent is 60-90%, the regeneration rate of the carbon dioxide capture absorbent is 50%-85%, and the regeneration energy consumption of the carbon dioxide capture absorbent is 2.2-3.2 GJ / t.

[0019] A second aspect of the present invention provides a method for capturing and absorbing carbon dioxide, comprising the following steps:

[0020] 1) contacting a gas source comprising the carbon dioxide with the carbon dioxide capture absorbent according to any one of claims 1 to 7, so that the carbon dioxide is captured and absorbed by the carbon dioxide capture absorbent to obtain a carbon dioxide-enriched liquid;

[0021] Wherein, the flow ratio of the carbon dioxide capture absorbent and the gas source including the carbon dioxide is 1.5-4:1;

[0022] 2) heating the carbon dioxide-enriched liquid to desorb carbon dioxide from the carbon dioxide-enriched liquid, thereby obtaining a hot solution and the carbon dioxide.

[0023] In the above method, the volume fraction of the carbon dioxide in the gas source comprising carbon dioxide is 5%-30%.

[0024] The method as described above, wherein the heating comprises preheating the carbon dioxide-enriched liquid using the hot solution obtained in step 2).

[0025] The carbon dioxide capture absorbent of the present invention has a high main absorbent content of 40% to 70% by mass, and includes a promoter, a corrosion inhibitor, and an antioxidant, so that the water content is lower than that of conventional carbon dioxide absorbents. This is a water-poor absorbent with a high main absorbent concentration, which not only helps to increase the carbon dioxide absorption capacity of the carbon dioxide capture absorbent, but also helps to reduce the amount of water evaporation during the carbon dioxide desorption process, thereby helping to reduce regeneration energy consumption. The present invention defines the formula of the main absorbent and promoter in the carbon dioxide capture absorbent and the viscosity of the carbon dioxide capture absorbent, which helps to improve the mass transfer performance of carbon dioxide in the aforementioned water-poor absorbent, thereby improving the ability of the carbon dioxide capture absorbent to capture and absorb carbon dioxide. More importantly, through the synergistic combination of the main absorbent, promoter, corrosion inhibitor, and antioxidant, the regeneration effect of the carbon dioxide capture absorbent is improved and the regeneration energy consumption is reduced, thereby helping to reduce the cost of carbon dioxide capture and absorption. DETAILED DESCRIPTION

[0026] In order to make the objects, technical solutions and advantages of the present application clearer, the following will be combined with the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0027] The present application provides a carbon dioxide capture absorbent, which comprises, in terms of mass percentage, 40-70% of a main absorbent, 1-20% of a promoter, 0.05-1% of a corrosion inhibitor, and 0.1-1% of an antioxidant, and the balance being water.

[0028] The main absorbent comprises, in terms of mass percentage, 0-40% of a fatty amine and 60-100% of an alcohol amine, the fatty amine comprising at least one of a primary amine, a secondary amine, a tertiary amine and a polyamine, and the alcohol amine comprising at least one of a monohydroxy, a dihydroxy and a trihydroxy.

[0029] The promoter comprises at least one of a salt, a steric amine and a sulfur-containing organic compound comprising S=O, the salt comprising at least one of a quaternary amine salt, an amino acid salt and a citric acid salt, the steric amine comprising at least one of 2-amino-2-methyl-1,3-propanediol, 2-amino-2-methyl-1-propanol and t-butylaminoethoxyethanol, and the sulfur-containing organic compound comprising at least one of dimethyl sulfone, sulfolane and dimethyl sulfoxide, the mass ratio of the salt, the steric amine and the sulfur-containing organic compound being (0-2):(0-4):(0-6).

[0030] The carbon dioxide capture absorbent has a viscosity of ≤20 cp.

[0031] The carbon dioxide capture absorbent of the present application can capture and absorb carbon dioxide by chemical reaction with carbon dioxide, and then desorb the carbon dioxide by heating, so that the carbon dioxide capture absorbent can be regenerated and recycled.

[0032] The carbon dioxide capture absorbent's ability to absorb carbon dioxide, regeneration effect and regeneration energy consumption are the three most critical performances affecting its application prospect. In the present application, the carbon dioxide capture absorbent's ability to absorb carbon dioxide is expressed by carbon dioxide removal rate, carbon dioxide removal rate = (concentration of carbon dioxide in the gas source at the inlet of the absorption tower - concentration of carbon dioxide in the gas source at the outlet of the absorption tower) / concentration of carbon dioxide in the gas source at the inlet of the absorption tower; the regeneration effect of the carbon dioxide capture absorbent is expressed by regeneration rate, regeneration rate = amount of carbon dioxide desorbed from the carbon dioxide-rich liquid / amount of carbon dioxide in the carbon dioxide-rich liquid before desorption; the regeneration energy consumption refers to the heat energy consumed in the process of desorbing carbon dioxide after the carbon dioxide capture absorbent absorbs carbon dioxide, which is calculated by the enthalpy value of steam consumption per unit of carbon dioxide capture amount.

[0033] In the carbon dioxide capture absorbent of the present application, the main absorbent plays a role in absorbing carbon dioxide, and its mass percentage content is 40% to 70%, which is relatively high, is conducive to increasing the carbon dioxide absorption capacity and improving the carbon dioxide absorption capacity, and also reduces the water content in the capture absorbent, so that the water evaporation amount in the carbon dioxide desorption process is reduced, which is conducive to reducing the regeneration energy consumption. The following takes fatty amine as an example to illustrate the reaction of the main absorbent with CO2:

[0034] Formula 1 represents the reaction of primary amine and secondary amine with CO2, and formula 2 represents the reaction of tertiary amine and hindered amine with CO2. The reaction of alcohol amine with CO2 is similar to the above reaction.

[0035] Meanwhile, the present application also optimizes the formula of the main absorbent and the promoter and limits the viscosity of the capture absorbent, the absorbent viscosity ≤ 20 cp, and the higher concentration of the main absorbent, the specific formula of the promoter and other synergistic cooperation, solves the problem of difficult carbon dioxide mass transfer of the lean water absorbent with high concentration of main absorbent, thereby ensuring that the above-mentioned carbon dioxide capture absorbent has high ability to absorb carbon dioxide.

[0036] The promoter of the present application includes salts, steric amine and sulfur-containing organic matter, the salts include at least one of quaternary ammonium salt, amino acid salt, citrate, the steric amine includes at least one of 2-amino-2-methyl-1, 3-propanediol, 2-amino-2-methyl-1-propanol, t-butyl amino ethoxy ethanol, and the sulfur-containing organic matter includes at least one of dimethyl sulfone, sulfolane, dimethyl sulfoxide, and the mass ratio of the salts, steric amine and sulfur-containing organic matter is (0-2) :(0-4) :(0-6);In addition to the effect of assisting carbon dioxide absorption and improving carbon dioxide absorption capacity, more importantly, on the basis of limiting the viscosity of the absorbent, the promoter of the above-mentioned formula can reduce the pH value of the solution and the hydrogen bond strength of the solution, thereby improving the regeneration effect of the carbon dioxide capture absorbent of the present application, avoiding the problem of poor regeneration effect of the lean water absorbent with high concentration of main absorbent, and being beneficial to the recycling of the carbon dioxide capture absorbent, further reducing the regeneration energy consumption in the carbon dioxide desorption process, having the advantages of cost saving and environmental friendliness.

[0037] The role of the corrosion inhibitor is to slow down the corrosion speed of the carbon dioxide capture absorbent on the equipment and prolong the service life of the equipment. The present application does not particularly limit the type of the above-mentioned corrosion inhibitor, and a commonly used corrosion inhibitor in the art can be used, for example, an oxidizing corrosion inhibitor and / or a surface adsorption type corrosion inhibitor. The above-mentioned oxidizing corrosion inhibitor forms an oxidation protective film on the equipment by oxidation, thereby slowing down the corrosion speed on the equipment, and the oxidizing corrosion inhibitor can include at least one of sodium molybdate, sodium metavanadate, sodium thiosulfate, zinc acetate, copper carbonate, sodium tungstate, sodium tetraborate, sodium vanadate and manganate. The above-mentioned surface adsorption type corrosion inhibitor forms a protective film on the surface of the equipment by adsorption, thereby achieving the purpose of protecting the equipment, and the surface adsorption type corrosion inhibitor can include a straight-chain alkane containing one amino group and having a carbon atom number of 1-20.

[0038] The antioxidant can slow down the oxidative degradation speed of the carbon dioxide capture absorbent. By using specific main absorbent, promoter and antioxidant at specific concentrations, the three cooperate with each other to maximize the carbon dioxide absorption capacity and regeneration capacity of the carbon dioxide capture absorbent while minimizing the regeneration energy consumption. The present application also does not particularly limit the type of the above-mentioned antioxidant, and a commonly used antioxidant in the art can be used, for example, at least one of acetaldoxime, propionaldoxime, hydroxyethylidene diphosphonic acid, ethylenediaminetetraacetic acid, ascorbic acid, sodium sulfite, potassium sulfite, ammonium sulfite, ammonium nitrite and potassium sodium tartrate.

[0039] The carbon dioxide capture absorbent of the present application has high carbon dioxide absorption capacity, good regeneration effect and low regeneration energy consumption, has the advantages of cost saving and environmental friendliness, and has wide application prospect.

[0040] In some embodiments, the number of nitrogen atoms in the above-mentioned fatty amines is ≤3, and the number of carbon atoms is ≤6, which is conducive to increasing the absorption capacity of the carbon dioxide capture absorbent for carbon dioxide, reducing the viscosity of the carbon dioxide capture absorbent, improving the mass transfer effect of carbon dioxide, thereby improving the absorption capacity of the carbon dioxide capture absorbent for carbon dioxide, and improving the regeneration effect of the carbon dioxide capture absorbent and reducing the regeneration energy consumption.

[0041] In some embodiments, the number of nitrogen atoms in the above-mentioned alcohol amines is ≤3, and the number of carbon atoms is ≤6, which is conducive to increasing the absorption capacity of the carbon dioxide capture absorbent for carbon dioxide, increasing the water solubility of the absorbent, reducing the volatility, reducing the viscosity of the carbon dioxide capture absorbent, improving the mass transfer effect of carbon dioxide, thereby improving the absorption capacity of the carbon dioxide capture absorbent for carbon dioxide, and reducing the regeneration energy consumption.

[0042] Further, the quaternary ammonium salt in the above-mentioned promoter includes at least one of triethylammonium benzoate or methylbenzyl quaternary ammonium benzoate, the amino acid salt includes α-aminoacetic acid salt, 2-aminopropanoic acid salt, 3-aminopropanoic acid salt, 2-amino-3-methylbutyric acid salt, α-aminoisohexanoic acid salt, α-amino-β-methylvaleric acid salt, 2-aminophenylalanine salt, α-imino acid salt, β-indole alanine salt, L-2-amino-3-hydroxypropanoic acid salt, 2-amino-3-p-hydroxyphenylpropanoic acid salt, L-2-amino-3-mercapto propanoic acid salt, glutamic acid salt, methylthiobutyric acid salt, β-hydroxy-α-aminobutyric acid salt, aspartic acid salt, α-aminoglutaric acid salt, 2,6-diaminohexanoic acid salt, 2-amino-5-guanidinovaleric acid salt, α-amino β-imidazolylpropanoic acid salt, triethylammonium benzoate, which is conducive to enhancing the regeneration effect of the carbon dioxide capture absorbent and greatly reducing the regeneration energy consumption.

[0043] Still further, when the salt includes an amino acid salt, the steric amine includes 2-amino-2-methyl-1-propanol, the sulfur-containing organic matter includes dimethyl sulfone, and the mass ratio of the salt, the steric amine, and the sulfur-containing organic matter is 1:2:3, the promoter composed of the above-mentioned salt, the steric amine, and the sulfur-containing organic matter can better enhance the regeneration effect of the carbon dioxide capture absorbent and greatly reduce the regeneration energy consumption.

[0044] Since the carbon dioxide desorption process is an endothermic process, in order to avoid the components in the carbon dioxide capture absorbent from being degraded or volatilized by heat, the present application further limits the boiling point of the steric amine in the above-mentioned promoter to be >160°C, which is conducive to avoiding the volatilization of the steric amine by heat, improving the stability of the carbon dioxide capture absorbent during the desorption process, improving the regeneration effect of the carbon dioxide capture absorbent, and also reducing the regeneration energy consumption and saving costs.

[0045] The inventors have found through a large number of studies that when the corrosion inhibitor comprises sodium metavanadate, and the mass percentage of sodium metavanadate in the above-mentioned carbon dioxide capture absorbent is 0.05%-0.2%, preferably 0.1%, it helps to further reduce the corrosion rate of the equipment.

[0046] When the antioxidant comprises potassium sodium tartrate, and the mass percentage of potassium sodium tartrate in the above-mentioned carbon dioxide capture absorbent is 0.1%-0.3%, preferably 0.2%, the oxidation degradation rate of the carbon dioxide capture absorbent can be more obviously reduced, and the regeneration effect of the carbon dioxide capture absorbent is better in cooperation with the main absorbent, the promoter, etc.

[0047] In some embodiments, the carbon dioxide removal rate of the above-mentioned carbon dioxide capture absorbent is 60%-90%, the regeneration rate of the carbon dioxide capture absorbent is 50%-85%, and the regeneration energy consumption of the carbon dioxide capture absorbent is 2.2-3.2 GJ / t. It can be seen that the carbon dioxide capture absorbent of the present application has high carbon dioxide absorption capacity, and has good regeneration effect and low regeneration energy consumption.

[0048] The second aspect of the present application provides a carbon dioxide capture and absorption method, comprising the following steps:

[0049] 1) contacting a gas source comprising carbon dioxide with the carbon dioxide capture absorbent of the first aspect of the present application, so that the carbon dioxide is captured and absorbed by the carbon dioxide capture absorbent, to obtain a carbon dioxide-rich liquid;

[0050] Wherein, the flow ratio of the above-mentioned carbon dioxide capture absorbent and the gas source comprising carbon dioxide is (1.5-4):1;

[0051] 2) heating treatment is performed on the carbon dioxide-rich liquid, so that the carbon dioxide is desorbed from the carbon dioxide-rich liquid, to obtain a hot solution and carbon dioxide.

[0052] The above-mentioned carbon dioxide capture and absorption method is a method for capturing and absorbing carbon dioxide using the carbon dioxide capture absorbent of the present application.

[0053] In the above-mentioned step 1), the gas source comprising carbon dioxide is contacted with the carbon dioxide capture absorbent, so that the carbon dioxide performs mass transfer diffusion in the carbon dioxide capture absorbent, reacts with the carbon dioxide capture absorbent, and is further captured and absorbed by the carbon dioxide capture absorbent, thereby obtaining a carbon dioxide-rich liquid.

[0054] In the above process, in order to improve the treatment efficiency of carbon dioxide, the gas source and the carbon dioxide capture absorbent should be fully contacted. The application does not limit the specific contact method. For example, the gas source can be introduced into the bottom of the absorption tower, and the carbon dioxide capture absorbent can be introduced into the top of the absorption tower, so that the two are countercurrently contacted in the absorption tower. This countercurrent contact method has the advantages of large contact area and sufficient reaction, and can make the carbon dioxide be fully absorbed by the carbon dioxide capture absorbent.

[0055] The application does not limit the flow rate of the gas source and the carbon dioxide capture absorbent introduced into the absorption tower, as long as the gas source and the carbon dioxide capture absorbent are fully contacted. The flow rate can be adjusted in combination with the carbon dioxide absorption capacity of the carbon dioxide capture absorbent and the carbon dioxide content in the gas source.

[0056] In some embodiments, the flow rate ratio of the carbon dioxide capture absorbent and the gas source containing carbon dioxide is (1.5-4):1 (L / h) / (Nm 3 / h), preferably (1.8-3.6):1 (L / h) / (Nm 3 / h), and the carbon dioxide capture absorbent can fully capture and absorb the carbon dioxide. This indicates that the carbon dioxide capture absorbent of the application has high carbon dioxide absorption capacity.

[0057] In the above step 2), the carbon dioxide-rich liquid is heated to a certain extent, and carbon dioxide can be desorbed therefrom, thereby obtaining a hot solution and carbon dioxide. The carbon dioxide can be directly used or sequestered, thereby realizing the capture and absorption of carbon dioxide.

[0058] The above carbon dioxide desorption process can be carried out in a regeneration tower provided with a heating device and a gas collection device, which is beneficial to the desorption and collection of carbon dioxide.

[0059] Generally, the heating treatment of the carbon dioxide-rich liquid can be saturated steam heating, which is beneficial to rapid heating of the carbon dioxide-rich liquid and energy saving. For example, in some embodiments, water vapor with a pressure of 0.4 MPa is used for heating.

[0060] The carbon dioxide capture and absorption method provided by the application can efficiently capture and absorb carbon dioxide by using the above carbon dioxide capture and absorption agent, has large treatment capacity, high treatment efficiency, and simple operation, and is suitable for industrialization.

[0061] The above carbon dioxide capture and absorption method can be used to capture and absorb carbon dioxide in flue gas discharged from a power plant.

[0062] When the volume fraction of carbon dioxide in the above gas source containing carbon dioxide is 5%-30%, the carbon dioxide in the above gas source can be effectively captured and absorbed by the capture and absorption method of the application.

[0063] The carbon dioxide enriched liquid in step 2) is heated to desorb carbon dioxide therefrom, and a hot solution and carbon dioxide are obtained, the hot solution having higher heat. In order to avoid waste of heat in the hot solution, the above heating includes preheating the carbon dioxide enriched liquid by using the hot solution obtained in step 2), i.e. using the hot solution as a heat source for the next carbon dioxide desorption, and transferring part of the heat in the hot solution to the carbon dioxide enriched liquid to be desorbed for desorption of carbon dioxide, so that the heat in the hot solution is fully utilized, energy waste is avoided, and the regeneration energy consumption is further reduced.

[0064] The above preheating process can be performed in a heat exchanger.

[0065] In some embodiments, in order to desorb carbon dioxide from the carbon dioxide desorption liquid with the lowest energy consumption, the carbon dioxide enriched liquid in step 2) can be introduced from the bottom of the regeneration tower and heated by saturated water vapor to produce a mixed gas of water vapor and carbon dioxide, the mixed gas flows from bottom to top, and the preheated carbon dioxide enriched liquid introduced from the top of the regeneration tower is countercurrently contacted to realize mass transfer and heat transfer, and the desorbed carbon dioxide is obtained from the top of the regeneration tower, and the hot solution is obtained from the bottom of the regeneration tower. The above process fully utilizes heat exchange, countercurrent contact and other methods to minimize the regeneration energy consumption.

[0066] Hereinafter, the carbon dioxide capture absorbent and the carbon dioxide capture and absorption method of the present application will be described in more detail through specific examples and comparative examples.

[0067] Example 1

[0068] The present embodiment provides a carbon dioxide capture absorbent, which comprises, in terms of mass percentage, 40% of a main absorbent, 10% of a promoter, 1% of sodium molybdate, and 0.5% of sodium sulfite; and the balance is water.

[0069] The main absorbent comprises, in terms of mass percentage, 12.5% of ethylenediamine and 87.5% of diethanolamine.

[0070] The promoter comprises salts, steric amine and sulfur-containing organic matter, the salt is sodium citrate, the steric amine is 2-amino-2-methyl-1,3-propanediol (AMP), and the sulfur-containing organic matter is dimethyl sulfoxide, and the mass ratio of the above salt, steric amine and sulfur-containing organic matter is 1:2:3.

[0071] The viscosity of the carbon dioxide capture absorbent is ≤20 cp.

[0072] The present embodiment also provides a carbon dioxide capture and absorption method, which comprises the following steps:

[0073] 1) introducing flue gas containing carbon dioxide into a carbon dioxide capture tower at a flow rate of 830 Nm 3 / h is introduced into the bottom of the absorption tower and countercurrently contacts the above-mentioned carbon dioxide capturing absorbent introduced into the top of the absorption tower at a flow rate of 1500 L / h, so that the carbon dioxide is captured and absorbed by the above-mentioned carbon dioxide capturing absorbent, and a carbon dioxide enrichment liquid is obtained;

[0074] wherein the volume fraction of carbon dioxide in the flue gas is 12%, and the flow rate ratio of the carbon dioxide capturing absorbent to the flue gas containing carbon dioxide is 1.8:1 (L / h / (Nm 3

[0075] 2) The above-mentioned carbon dioxide enrichment liquid is introduced into the bottom of the regeneration tower at a flow rate of 1550 L / h, and is heated by saturated water vapor at a flow rate of 180 kg / h and a pressure of 0.4 MPa to obtain a mixed gas of water vapor and carbon dioxide; the carbon dioxide enrichment liquid preheated to 85-95°C is introduced into the top of the regeneration tower at a flow rate of 150 L / h, countercurrently contacts the above-mentioned mixed gas, and after sufficient reaction, a hot solution is obtained from the bottom of the regeneration tower and carbon dioxide gas is obtained from the top of the regeneration tower;

[0076] wherein the above-mentioned hot solution is used to preheat the carbon dioxide enrichment liquid in the heat exchanger.

[0077] Example 2

[0078] This example is basically the same as Example 1, except that:

[0079] The mass percentage content of the main absorbent in the carbon dioxide capturing absorbent is 50%, and other conditions remain unchanged.

[0080] Example 3

[0081] This example is basically the same as Example 1, except that:

[0082] The mass percentage content of the main absorbent in the carbon dioxide capturing absorbent is 60%, and other conditions remain unchanged.

[0083] Example 4

[0084] This example is basically the same as Example 1, except that:

[0085] The mass percentage content of the main absorbent in the carbon dioxide capturing absorbent is 70%, and other conditions remain unchanged.

[0086] Example 5

[0087] This example is basically the same as Example 1, except that:

[0088] The mass percentage content of the promoter in the carbon dioxide capturing absorbent is 20%, and the mass percentage content of sodium sulfite is 1%; other conditions remain unchanged.

[0089] ​Example 6

[0090] This example is basically identical with Example 1, except that:

[0091] The main absorbent comprises 12.5% ethylenediamine and 87.5% monoethanolamine by mass percentage.

[0092] Example 7

[0093] This example is basically identical with Example 1, except that:

[0094] The main absorbent comprises 12.5% diethylenetriamine and 87.5% diethanolamine by mass percentage.

[0095] Example 8

[0096] This example is basically identical with Example 1, except that:

[0097] The accelerator comprises a salt, a hindered amine and a sulfur-containing organic compound, the salt is α-aminoacetate and 2-aminopropanoate, the hindered amine is 2-amino-2-methyl-1-propanol, and the sulfur-containing organic compound is dimethyl sulfone, the mass ratio of the salt, the hindered amine and the sulfur-containing organic compound is 1:2:3, and other conditions remain unchanged.

[0098] Example 9

[0099] This example is basically identical with Example 1, except that:

[0100] The hindered ammonium is replaced by 2-amino-2-methyl-1-propanol (AMPD) instead of 2-amino-2-methyl-1,3-propanediol (AMP), and other conditions remain unchanged.

[0101] Example 10

[0102] This example is basically identical with Example 1, except that:

[0103] The accelerator comprises a salt, a hindered amine and a sulfur-containing organic compound, the salt is 2-aminopropanoate sodium, the hindered amine is 2-amino-2-methyl-1-propanol, and the sulfur-containing organic compound is dimethyl sulfone, the mass ratio of the salt, the hindered amine and the sulfur-containing organic compound is 1:2:3, and other conditions remain unchanged.

[0104] Example 11

[0105] This example is basically identical with Example 1, except that:

[0106] Sodium metavanadate 0.2% is used to replace sodium molybdate 1%.

[0107] Example 12

[0108] This example is basically identical with Example 1, except that:

[0109] Sodium sulfite 0.5% was replaced by sodium potassium tartrate 0.3%.

[0110] Example 13

[0111] This example is basically identical with Example 1, except that:

[0112] The volume fraction of carbon dioxide in the flue gas was 20%.

[0113] Example 14

[0114] This example is basically identical with Example 1, except that:

[0115] The main absorbent included 12.5% amino octane and 87.5% diethanolamine by mass percentage; other conditions remained unchanged.

[0116] Example 15

[0117] This example is basically identical with Example 1, except that:

[0118] The main absorbent included 12.5% ethylenediamine and 87.5% N-methylcyclohexylamine by mass percentage; other conditions remained unchanged.

[0119] Comparative Example 1

[0120] This comparative example is basically identical with Example 1, except that:

[0121] The main absorbent included 100% di-n-butylamine by mass percentage; other conditions remained unchanged.

[0122] Comparative Example 2

[0123] This comparative example is basically identical with Example 1, except that:

[0124] The accelerator was a sulfur-containing organic compound, and the sulfur-containing organic compound was dimercapto propanol.

[0125] Comparative Example 3

[0126] This comparative example is basically identical with Example 1, except that:

[0127] The main absorbent was 12.5% diethylenetriamine and 87.5% triisopropanolamine,

[0128] The viscosity of the carbon dioxide capture absorbent in this comparative example was 35 cp.

[0129] Test Example

[0130] 1. The following parameters were detected for the above examples and comparative examples:

[0131] 1) Carbon dioxide removal rate: The concentration of carbon dioxide in the gas source was detected by infrared spectroscopy method, and the carbon dioxide removal rate = (the concentration of carbon dioxide in the gas source at the inlet of the absorption tower - the concentration of carbon dioxide in the gas source at the outlet of the absorption tower) / the concentration of carbon dioxide in the gas source at the inlet of the absorption tower, and the specific results are shown in Table 1;

[0132] 2) Regeneration rate of absorbent: Regeneration rate = the amount of carbon dioxide desorbed from the carbon dioxide-rich liquid / the amount of carbon dioxide in the carbon dioxide-rich liquid before desorption, wherein the amount of carbon dioxide desorbed from the carbon dioxide-rich liquid is detected by a wet gas flow meter, and the amount of carbon dioxide in the carbon dioxide-rich liquid before desorption is detected by acid-base titration, and the specific results of the regeneration rate are shown in Table 1;

[0133] 3) Regeneration energy consumption: Calculated by the enthalpy value of the steam consumption per unit of carbon dioxide capture amount, the calculation formula is: regeneration energy consumption = steam consumption x (reboiler inlet steam enthalpy - reboiler outlet steam enthalpy) / the amount of carbon dioxide desorbed, and the specific results are shown in Table 1;

[0134] 4) Coupon corrosion rate: detected by the method specified in HGT2159-91, and the specific results are shown in Table 1.

[0135] 2, detection results

[0136] Table 1: Related parameters of carbon dioxide capture absorbent

[0137] The results of Table 1 show that:

[0138] 1) The carbon dioxide removal rate data of Examples 1-4 shows that increasing the concentration of the main absorbent helps to improve the carbon dioxide removal rate;

[0139] 2) Example 5 adjusts the concentration of the promoter, which improves the carbon dioxide removal rate and reduces the regeneration energy consumption of the carbon dioxide capture absorbent;

[0140] 3) Compared with Examples 1, 14 and 15, Examples 6 and 7 adjust the formula of the main absorbent, which improves the performance of the carbon dioxide capture absorbent;

[0141] 4) Examples 8 and 10 optimize the formula of the promoter, which further improves the performance of the carbon dioxide capture absorbent based on Example 1.

[0142] 5) The carbon dioxide capture absorbent formula of Comparative Examples 1-3 is different from that of Example 1, which results in low carbon dioxide removal rate, low regeneration rate or high regeneration energy consumption.

[0143] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A carbon dioxide capture absorbent, characterized in that: The carbon dioxide capture absorbent comprises, by weight percentage, 40%-70% of a main absorbent, 1%-20% of a accelerator, 0.05%-1% of a corrosion inhibitor, and 0.1%-1% of an antioxidant; the balance being water; The main absorbent comprises 0-40% of aliphatic amine and 60-100% of alcohol amine in terms of mass percentage, wherein the aliphatic amine comprises at least one of primary amine, secondary amine, tertiary amine and polyamine, and the alcohol amine comprises at least one of monohydroxy, dihydroxy and trihydroxy; The accelerator includes at least one of a salt, a hindered amine, and a sulfur-containing organic compound including S=O, the salt includes at least one of a quaternary ammonium salt, an amino acid salt, and a citrate, the hindered amine includes at least one of 2-amino-2-methyl-1,3-propanediol, 2-amino-2-methyl-1-propanol, and tert-butylaminoethoxyethanol, the sulfur-containing organic compound includes at least one of dimethyl sulfone, sulfolane, and dimethyl sulfoxide, and the mass ratio of the salt, the hindered amine, and the sulfur-containing organic compound is (0-2):(0-4):(0-6); The viscosity of the carbon dioxide capture absorbent is ≤20cp.

2. The carbon dioxide capture absorbent according to claim 1, characterized in that The number of nitrogen atoms in the fatty amine is ≤3, and the number of carbon atoms is ≤6; And / or, the number of nitrogen atoms in the alcoholamine is ≤3, and the number of carbon atoms is ≤6.

3. The carbon dioxide capture absorbent according to claim 1 or 2, characterized in that The salts include amino acid salts, the hindered amines include 2-amino-2-methyl-1-propanol, the sulfur-containing organic matter includes dimethyl sulfone, and the mass ratio of the salts, the hindered amines and the sulfur-containing organic matter is 1:2:

3.

4. The carbon dioxide capture absorbent according to any one of claims 1 to 3, characterized in that The boiling point of the hindered amine is greater than 160°C.

5. The carbon dioxide capture absorbent according to any one of claims 1 to 4, characterized in that: The corrosion inhibitor comprises sodium metavanadate, and the mass percentage of the sodium metavanadate in the carbon dioxide capture absorbent is 0.05%-0.2%.

6. The carbon dioxide capture absorbent according to any one of claims 1 to 5, characterized in that: The antioxidant includes potassium sodium tartrate, and the mass percentage of the potassium sodium tartrate in the carbon dioxide capture absorbent is 0.1%-0.3%.

7. The carbon dioxide capture absorbent according to any one of claims 1 to 6, characterized in that: The carbon dioxide removal rate of the carbon dioxide capture absorbent is 60%-90%, the regeneration rate of the carbon dioxide capture absorbent is 50%-85%, and the regeneration energy consumption of the carbon dioxide capture absorbent is 2.2-3.2 GJ / t.

8. A method for capturing and absorbing carbon dioxide, characterized in that: The following steps are involved: 1) contacting a gas source comprising the carbon dioxide with the carbon dioxide capture absorbent according to any one of claims 1 to 7, so that the carbon dioxide is captured and absorbed by the carbon dioxide capture absorbent to obtain a carbon dioxide-enriched liquid; Wherein, the flow ratio of the carbon dioxide capture absorbent and the gas source including the carbon dioxide is (1.5-4):1; 2) heating the carbon dioxide-enriched liquid to desorb carbon dioxide from the carbon dioxide-enriched liquid, thereby obtaining a hot solution and the carbon dioxide.

9. The method according to claim 8, characterized in that The volume fraction of the carbon dioxide in the gas source including carbon dioxide is 5%-30%.

10. The method according to claim 8 or 9, characterized in that The heating includes preheating the carbon dioxide-enriched liquid using the hot solution obtained in step 2).

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