Carbon dioxide absorbent and absorption and regeneration method thereof

Abstract

The invention discloses a carbon dioxide absorbent and an absorption and regeneration method thereof. The absorbent comprises the following components in parts by weight: 15-40 parts of tertiary amine, 15-70 parts of polyamine, 1-20 parts of sterically hindered amine, 1-20 parts of an activating agent and 1-5 parts of amino-containing organic acid. The carbon dioxide absorbent provided by the invention has the characteristics of low desorption energy consumption, rapid separation and rapid regeneration, and the regeneration process is simple and easy to popularize. The efficient gas-liquid mass transfer equipment is used for achieving the heat and mass coordinated transfer process in the gas-liquid reaction and separation process, the mass transfer coefficient of carbon dioxide molecules on a solvent / water vapor interface is increased, the carbon dioxide separation efficiency is indirectly improved, and the characteristic that the liquid film carbon dioxide molecule concentration is high at the regeneration temperature of a low-energy-consumption solvent is coupled. The quantity of solvent entrained by the carbon dioxide generated by the invention is less, and the loss of the solvent in the cooling separation process is effectively reduced.

Description

Technical Field

[0001] The invention relates to the field of carbon dioxide absorption, and in particular to a carbon dioxide absorbent and an absorption and regeneration method thereof. Background Art

[0002] The separation technologies for carbon dioxide emitted from industrial processes include absorption, adsorption and membrane methods. Among them, the absorption method has the longest history of development and is widely used in the separation of various industrial processes and terminal gases. The absorption method is divided into physical absorption and chemical absorption according to the application conditions and system characteristics. The physical absorption method is more suitable for high-partial-pressure process gases containing carbon dioxide, and can effectively use the pressure difference change to achieve low-energy-consumption carbon dioxide separation and purification. The chemical absorption method relies on the difference in the ability of chemical solvents to bind to carbon dioxide at different temperatures to achieve high-purity separation of carbon dioxide, and is suitable for the separation of carbon dioxide in industrial gases with lower concentrations and partial pressures. However, when the chemical absorption method desorbs carbon dioxide under high-temperature conditions, the existing solvents have the problem of high desorption energy consumption, which restricts large-scale industrial application.

[0003] CN103596662A discloses a carbon dioxide absorbent, which contains an amine compound, a weak acid compound and water, wherein the pKb of the amine compound in a 30°C aqueous solution is 4.0 to 7.0, and the weak acid compound is boric acid or a boric acid ester having a pKa of 7.0 to 10.0 in a 30°C aqueous solution. The carbon dioxide absorbent uses a boric acid compound as a weak acid. Such substances may precipitate boric acid solids under desorption conditions of a solvent above 100 degrees Celsius, which makes industrial application difficult.

[0004] CN112870919A discloses a supergravity regeneration energy-saving process for flue gas CO2 capture system, in which the rich liquid that absorbs CO2 gas is discharged from the bottom of the absorption tower, and the cold rich liquid pressurized by the rich liquid pump enters the lean-rich liquid heat exchanger for heat exchange, and then sprays into the supergravity reactor after heat exchange, so that CO2 is quickly desorbed from the absorbent, and the desorbed regenerated gas enters the gas-liquid separator through the regeneration gas outlet to obtain product gas after separation. Although the process of supergravity reactor regeneration is involved, the solvent type and characteristics are not clear, and the solvent's own performance does not match the supergravity technology, lacks the characteristics of deep coupling, and the energy-saving effect is also limited. Summary of the invention

[0005] The purpose of the present invention is to overcome the problem of high energy consumption of solvent desorption in the prior art, which is not conducive to industrial application, and to provide a carbon dioxide absorbent and its absorption and regeneration method. The carbon dioxide absorbent of the present invention has the characteristics of low desorption energy consumption, rapid separation and rapid regeneration, and the regeneration process is simple and easy to promote.

[0006] In order to achieve the above objectives, the first aspect of the present invention provides a carbon dioxide absorbent, which comprises: 15 to 40 parts by weight of a tertiary amine, 15 to 70 parts by weight of a polyamine, 1 to 20 parts by weight of a hindered amine, 1 to 20 parts by weight of an activator and 1 to 5 parts by weight of an organic acid containing an amino group.

[0007] A second aspect of the present invention provides a method for absorbing and regenerating a carbon dioxide absorbent, the method comprising the following steps:

[0008] contacting an absorption solution containing the carbon dioxide absorbent described in the first aspect with a gas containing carbon dioxide to absorb carbon dioxide and obtain a carbon dioxide-rich solution;

[0009] The carbon dioxide-rich solution is subjected to heat exchange and then gas-liquid separation to achieve regeneration of the absorption solution.

[0010] Through the above technical solution, the beneficial technical effects achieved by the present invention are as follows:

[0011] 1) The carbon dioxide absorbent of the present invention can remove carbon dioxide in gas and solution efficiently and stably through the synergistic effect of tertiary amines, polyamines, hindered amines, activators and amino acids or aminosulfonic acid. At the same time, the carbon dioxide absorbent of the present invention has the characteristics of low desorption energy consumption, rapid separation and rapid regeneration, and the regeneration process is simple and easy to promote.

[0012] 2) In the solution system of the present invention, carbon dioxide exists more in the form of molecules in the liquid film, making it easier to separate the gas and liquid from the medium, which is conducive to using equipment such as a rotary flash evaporator and a supergravity reactor to greatly increase the liquid film area, and to achieve carbon dioxide desorption with lower energy consumption. At the same time, this feature does not affect the absorption performance of the solvent system at a lower temperature.

[0013] 3) The carbon dioxide produced by the present invention carries less solvent, which effectively reduces the loss of solvent during the cooling and separation process. The carbon dioxide in the solvent after regeneration can be reduced to below 10g / L, and the output carbon dioxide gas concentration reaches more than 99%, which can be directly used for dehydration and impurity removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic flow diagram of a method for absorbing and regenerating a carbon dioxide absorbent provided in one embodiment of the present invention.

[0015] Description of Reference Numerals

[0016] 1Gas-liquid separation equipment 2Buffer heating tank 3Heat exchanger

[0017] 4 Gas-liquid separation cooler 5 Pump DETAILED DESCRIPTION

[0018] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0019] The first aspect of the present invention provides a carbon dioxide absorbent, which comprises: 15-40 parts by weight of a tertiary amine, 15-70 parts by weight of a polyamine, 1-20 parts by weight of a hindered amine, 1-20 parts by weight of an activator and 1-5 parts by weight of an organic acid containing an amino group.

[0020] In some preferred embodiments of the present invention, the absorbent comprises: 20-40 parts by weight of tertiary amine, 20-60 parts by weight of polyamine, 10-20 parts by weight of hindered amine, 5-20 parts by weight of activator and 3-5 parts by weight of amino-containing organic acid.

[0021] The carbon dioxide absorbent of the present invention can remove carbon dioxide in gas and solution efficiently and stably through the synergistic effect of tertiary amines, polyamines, hindered amines, activators and amino acids or aminosulfonic acid. At the same time, the carbon dioxide absorbent of the present invention has the characteristics of low desorption energy consumption, rapid separation and rapid regeneration, and the regeneration process is simple and easy to promote.

[0022] In some embodiments of the present invention, the tertiary amine has a structure shown in Formula I:

[0023]

[0024] Wherein, R1, R2 and R3 are each independently a C1-C3 alkyl group or an alkanol group.

[0025] In some preferred embodiments of the present invention, the tertiary amine is selected from one or more of methyldiethanolamine, diethylethanolamine, dimethylethanolamine and N,N-diisopropylethanolamine.

[0026] In some embodiments of the present invention, the polyamine has a structure shown in Formula II:

[0027]

[0028] Wherein, R4, R5, R6, R7 and R8 are each independently a hydrogen atom or an alkyl or alkanol group of C1 or above.

[0029] In some preferred embodiments of the present invention, the polyamine is selected from one or more of 3-methylaminopropylamine, hydroxyethylethylenediamine and 3,3'-bis(methylamino)-N-methyldipropylamine.

[0030] In some embodiments of the present invention, the hindered amine has a structure shown in Formula III:

[0031]

[0032] Among them, R9, R 10 , R 11 and R 12 are independently H, alkyl or alkanol, and R9, R 10 and R 11 At most one is H.

[0033] In some preferred embodiments of the present invention, the hindered amine is selected from one or more of 2-amino-2-methyl-1-propanol, 1-amino-2-methyl-2-propanol, tert-butylaminoethanolamine and 2-(isopropylamino)ethanol.

[0034] In some embodiments of the present invention, the activator has a structure shown in Formula IV:

[0035]

[0036] Among them, R 13 is H, C1-C3 alkyl, aminoalkyl or alkanol, R 14 and R 15 Each is independently H or a C1-C3 alkyl or alkanol group; M is a substituted or unsubstituted methylene group, a heteroatom or a group containing a heteroatom.

[0037] Preferably, the activator contains a 6-membered saturated heterocyclic ring having two or more nitrogen groups.

[0038] In some preferred embodiments of the present invention, the activator is selected from one or more of piperazine, 2-methylpiperazine, N-methylpiperazine, N-ethylpiperazine, N-aminoethylpiperazine, piperidine and morpholine.

[0039] In some embodiments of the present invention, the amino group-containing organic acid is selected from one or more of amino acids or amino group-containing sulfonic acids.

[0040] In the present invention, the amino acid contains at least one amino group and at least one carboxylic acid group in its molecular structure, including α-amino acids or β-amino acids, α and β refer to the adjacent position and the second position of the carboxylic acid group from the amino group, respectively. In the present invention, carboxylic acids containing 2 to 4 carbon atoms are preferred.

[0041] In some preferred embodiments of the present invention, the amino acid is selected from one or more of glycine (aminoacetic acid), sarcosine (N-methylglycine), alanine (2-aminopropionic acid), β-alanine (3-aminopropionic acid), serine and methionine;

[0042] In the present invention, the amino group-containing sulfonic acid contains at least one amino group and at least one sulfonic acid group in its molecular structure, and is α-aminosulfonic acid or β-aminosulfonic acid. α and β refer to the aminosulfonic acid at the adjacent position and the second position of the sulfonic acid group from the amino group, respectively. In the present invention, the sulfonic acid containing 1 to 4 carbon atoms is preferred.

[0043] In some preferred embodiments of the present invention, the amino group-containing sulfonic acid is selected from one or more of aminomethanesulfonic acid, taurine (2-aminoethanesulfonic acid) and 2-(methylamino)ethanesulfonic acid.

[0044] A second aspect of the present invention provides a method for absorbing and regenerating a carbon dioxide absorbent, the method comprising the following steps:

[0045] contacting an absorption solution containing the carbon dioxide absorbent described in the first aspect with a gas containing carbon dioxide to absorb carbon dioxide and obtain a carbon dioxide-rich solution;

[0046] The carbon dioxide-rich solution is subjected to heat exchange and then gas-liquid separation to achieve regeneration of the absorption solution.

[0047] In the present invention, the carbon dioxide absorbent comprises: 15 to 40 parts by weight of tertiary amine, 15 to 70 parts by weight of polyamine, 1 to 20 parts by weight of hindered amine, 1 to 20 parts by weight of activator and 1 to 5 parts by weight of organic acid containing amino group. Preferably, the absorbent comprises: 20 to 40 parts by weight of tertiary amine, 20 to 60 parts by weight of polyamine, 10 to 20 parts by weight of hindered amine, 5 to 20 parts by weight of activator and 3 to 5 parts by weight of organic acid containing amino group.

[0048] The specific selection of the above components is the same as that of the first aspect mentioned above. Please refer to the description of the first aspect mentioned above and will not be repeated here.

[0049] In some embodiments of the present invention, the solvent of the absorption solution is water or alcohol, and the concentration of the carbon dioxide absorbent in the absorption solution is 5-50wt%, preferably 25-45wt%.

[0050] In some embodiments of the present invention, the concentration of carbon dioxide in the carbon dioxide-rich solution is 25-90 g / L, preferably 45-85 g / L.

[0051] In some embodiments of the present invention, the temperature of the carbon dioxide-rich solution after heat exchange is 50-100°C, preferably 80-100°C.

[0052] In some embodiments of the present invention, the pressure of the regeneration process is -0.08 MPaG to 0.15 MPaG, preferably -0.02 MPaG to 0.12 MPaG.

[0053] In some embodiments of the present invention, the method further comprises: performing gas-liquid separation on part or all of the regenerated carbon dioxide lean solution to perform deep regeneration of the absorption solution.

[0054] In the present invention, part or all of the regenerated lean carbon dioxide solution is subjected to gas-liquid separation together with the aforementioned rich carbon dioxide solution after heat exchange, thereby achieving deep regeneration of the absorption solution.

[0055] In some embodiments of the present invention, the gas-liquid separation is performed in a gas-liquid separation device, specifically comprising the following steps:

[0056] The carbon dioxide-rich solution is sent to the gas-liquid separation device after heat exchange, and the carbon dioxide gas is separated by the gas-liquid separation device; the gas generated by the separation enters the gas-liquid separation cooler, and is cooled by the gas-liquid separation cooler to obtain carbon dioxide; the regenerated carbon dioxide-lean solution flows into the buffer heating tank, and part or all of the carbon dioxide-lean solution is returned to the gas-liquid separation device through a pump to perform deep regeneration of the absorption solution.

[0057] In the present invention, the gas separated by the supergravity reactor is a mixture of hot carbon dioxide and water vapor, which is cooled by the gas-liquid separation cooler to produce carbon dioxide with a purity of more than 99%. The regenerated lean carbon dioxide solution flows into the buffer heating tank due to gravity.

[0058] In some embodiments of the present invention, the gas-liquid flow direction of the carbon dioxide-rich solution in the gas-liquid separation device is gas-liquid countercurrent, gas-liquid cocurrent or gas-liquid baffled flow.

[0059] In some embodiments of the present invention, the gas-liquid separation equipment is a rotary flash evaporator or a supergravity reactor.

[0060] In some embodiments of the present invention, the rotation speed of the gas-liquid separation device is 100-1500 rpm, preferably 300-1000 rpm.

[0061] In some embodiments of the present invention, the temperature of the buffer heating tank is 55-115°C; preferably 85-115°C.

[0062] In the present invention, the heat source of the buffer heating tank can be realized by steam, electric heating, microwave heating and the like.

[0063] In some embodiments of the present invention, the pressure of the gas-liquid separation cooler is -0.07-0.14 MPaG.

[0064] The gas-liquid separation is carried out in a rotary flash evaporator or a high gravity reactor, and specifically comprises the following steps:

[0065] The carbon dioxide-rich solution enters the inner edge of the rotating impeller through the liquid distribution pipe, and the solution is further dispersed into micron-sized solution droplets, liquid filaments and liquid films. The gas-liquid interphase area is expanded by 2-3 orders of magnitude compared with the original. At this time, the mass transfer coefficient of carbon dioxide in the process of mass transfer from liquid phase to gas phase increases by 2-3 orders of magnitude. As the liquid contacts the steam from the reboiler in reverse, the carbon dioxide molecules enter the gas phase and are discharged from the top of the regenerator to complete the gas-liquid separation.

[0066] The carbon dioxide absorbent of the present invention is a low-energy solvent, which has the characteristic of increasing the degree of dissociation of the organic acid containing amino groups of the amphiphilic compound at the regeneration temperature. At the same temperature (energy conditions), the reaction equilibrium of the solvent molecules and the carbon dioxide molecules moves more toward the direction of generating carbon dioxide, and the carbon dioxide in the solution system exists more in the liquid film in the form of molecules, making it easier to separate the gas and liquid from the medium, and is conducive to using equipment such as a rotary flash evaporator and a supergravity reactor that greatly increases the liquid film area, so as to achieve carbon dioxide desorption with lower energy consumption. At the same time, this characteristic does not affect the absorption performance of the solvent system at a lower temperature.

[0067] The regeneration process of the present invention is carried out by utilizing high-efficiency gas-liquid mass transfer equipment, and realizes the coordinated transfer of heat and mass in the gas-liquid reaction and separation process by simulating the supergravity field through a centrifugal field, thereby overcoming the deficiencies of the traditional regeneration separation tower in mass transfer to a certain extent, improving the mass transfer coefficient of carbon dioxide molecules at the solvent / water vapor interface, indirectly improving the carbon dioxide separation efficiency, and coupling the characteristic of the low-energy consumption solvent of the present invention that the concentration of carbon dioxide molecules in the liquid film is high at the regeneration temperature.

[0068] The carbon dioxide produced by the present invention carries less solvent, effectively reducing the loss of solvent during the cooling and separation process. The carbon dioxide in the solvent after regeneration can be reduced to below 10g / L.

[0069] The concentration of carbon dioxide produced by the present invention can reach above 99%, and the dehydration and impurity removal process can be directly carried out.

[0070] The solvent and regeneration process of the present invention are simple and easy to promote.

[0071] According to a particularly preferred embodiment of the present invention, the gas-liquid separation is carried out in a gas-liquid separation device, such as Figure 1 As shown, the specific steps include:

[0072] The carbon dioxide-rich solution is sent to the gas-liquid separation device 1 after heat exchange through the heat exchanger 3. The gas-liquid separation device 1 can be selected from a rotary flash evaporator or a supergravity reactor. The carbon dioxide gas is separated by the gas-liquid separation device 1; the gas generated by the separation enters the gas-liquid separation cooler 4, and carbon dioxide is obtained after cooling by the gas-liquid separation cooler 4; the regenerated carbon dioxide-lean solution flows into the buffer heating tank 2, and part or all of the carbon dioxide-lean solution is returned to the gas-liquid separation device 1 through the pump 5 to perform deep regeneration of the absorption solution.

[0073] The present invention will be described in detail below through examples.

[0074] In the following examples and comparative examples, unless otherwise specified, all raw materials used were commercially available.

[0075] Example 1

[0076] A typical flue gas carbon dioxide recovery device includes an absorption tower, a desorption tower, a lean-rich liquid heat exchanger, a regeneration tower cooler and a reboiler, etc. The flue gas treatment capacity is 40,000 Nm 3 / h, carbon dioxide content 6.5%, flue gas temperature 38 ° C; the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 5 parts by weight of aminoacetic acid; the absorbent is configured to an absorbent solution with a mass concentration of 35%, and the flow rate of the absorbent solution is 140Nm 3 / h. The solution regeneration heat source uses low-pressure steam, and the regeneration device uses a reboiler and a regeneration tower.

[0077] In this process, the absorption rate of flue gas carbon dioxide is 83%, the steam consumption for 1 ton of carbon dioxide is 1.6 tons, and the absorbent solution consumption after 90 days of operation is 0.86 kg / t of carbon dioxide.

[0078] Example 2

[0079] The method of Example 1 is used, except that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 5 parts by weight of aminoacetic acid; the absorbent is configured into an absorbent solution with a mass concentration of 45%, and the flow rate of the absorbent solution is 140Nm 3 The other conditions are exactly the same as those in Example 1.

[0080] In this process, the absorption rate of flue gas carbon dioxide is 88%, and the steam consumption for 1 ton of carbon dioxide is 1.5 tons.

[0081] Example 3

[0082] The method of Example 1 is followed, except that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 5 parts by weight of aminoacetic acid; the absorbent is configured into an absorbent solution with a mass concentration of 30%, and the flow rate of the absorbent solution is 140Nm 3 The other conditions are exactly the same as those in Example 1.

[0083] In this process, the absorption rate of flue gas carbon dioxide is 80%, and the steam consumption for 1 ton of carbon dioxide is 1.6 tons.

[0084] Example 4

[0085] The method of Example 1 is used, except that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 1 part by weight of aminoacetic acid; the absorbent is configured into an absorbent solution with a mass concentration of 35%, and the flow rate of the absorbent solution is 140Nm 3 The other conditions are exactly the same as those in Example 1.

[0086] In this process, the absorption rate of flue gas carbon dioxide is 83%, the steam consumption for 1 ton of carbon dioxide is 1.7 tons, and the consumption of absorbent solution after 90 days of operation is 0.85 kg / t carbon dioxide.

[0087] Example 5

[0088] Use Figure 1 The flue gas carbon dioxide recovery device shown in the figure, wherein the gas-liquid separation device 1 is used in a rotary flash evaporator, and the flue gas processing capacity is 12000Nm 3 / h, carbon dioxide content 6.5%, flue gas temperature 38 ° C, the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 5 parts by weight of aminoacetic acid; the absorbent is configured into an absorbent solution with a mass concentration of 35%. The flow rate of the absorbent solution is 45Nm 3 / h. The feed temperature of the carbon dioxide-rich solution is 80°C. The solution regeneration heat source uses low-pressure steam, the regeneration speed is 350rpm, and the regeneration pressure is 35kPaG.

[0089] In this process, the absorption rate of flue gas carbon dioxide is 83%, the steam consumption for 1 ton of carbon dioxide is 1.0 ton, and the absorbent solution consumption for 90 days of operation is 0.7 kg / t carbon dioxide.

[0090] Example 6

[0091] The method of Example 5 is different in that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 5 parts by weight of aminoacetic acid; the absorbent is prepared into an absorbent solution with a mass concentration of 45%. The flow rate of the absorbent solution is 45Nm 3 The other conditions are exactly the same as those in Example 5.

[0092] During this process, the absorption rate of flue gas carbon dioxide is 87%, and the steam consumption for 1 ton of carbon dioxide is 0.9 tons.

[0093] Example 7

[0094] The method of Example 5 is different in that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 5 parts by weight of aminoacetic acid; the absorbent is prepared into an absorbent solution with a mass concentration of 5%. The flow rate of the absorbent solution is 45Nm 3 The other conditions are exactly the same as those in Example 5.

[0095] In this process, the absorption rate of flue gas carbon dioxide is 80%, and 1 ton of carbon dioxide steam is consumed at 1.9 tons.

[0096] Example 8

[0097] The method of Example 5 is followed, except that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 49 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 1 part by weight of aminoacetic acid; the absorbent is configured into an absorbent solution with a mass concentration of 35%, and the other conditions are exactly the same as in Example 5.

[0098] During this process, the absorption rate of flue gas carbon dioxide is 82%, and the steam consumption for 1 ton of carbon dioxide is 1.2 tons.

[0099] Example 9

[0100] The method of Example 5 is followed, except that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 3 parts by weight of aminoacetic acid; the absorbent is configured into an absorbent solution with a mass concentration of 35%, and the other conditions are exactly the same as in Example 5.

[0101] During this process, the absorption rate of flue gas carbon dioxide is 82%, and the steam consumption for 1 ton of carbon dioxide is 1.15 tons.

[0102] Example 10

[0103] The method of Example 5 is followed, except that the formula of the carbon dioxide absorbent used is as follows: 15 parts by weight of diethylethanolamine, 70 parts by weight of hydroxyethylethylenediamine, 5 parts by weight of 1-amino-2-methyl-2-propanol, 7 parts by weight of piperidine and 3 parts by weight of aminomethanesulfonic acid; the absorbent is configured into an absorbent solution with a mass concentration of 35%, and the other conditions are exactly the same as in Example 5.

[0104] In this process, the absorption rate of flue gas carbon dioxide is 85%, and the steam consumption for 1 ton of carbon dioxide is 1.3 tons.

[0105] Embodiment 11

[0106] The method of Example 5 is followed, except that the formula of the carbon dioxide absorbent used is as follows: 40 parts by weight of dimethylethanolamine, 15 parts by weight of 3,3'-bis(methylamino)-N-methyldipropylamine, 20 parts by weight of tert-butylaminoethanolamine, 20 parts by weight of morpholine and 5 parts by weight of 2-(methylamino)ethanesulfonic acid; the absorbent is configured into an absorbent solution with a mass concentration of 35%, and the other conditions are exactly the same as in Example 5.

[0107] During this process, the absorption rate of flue gas carbon dioxide is 81%, and the steam consumption for 1 ton of carbon dioxide is 1.1 tons.

[0108] Example 12

[0109] The method of Example 5 is followed, except that the formula of the carbon dioxide absorbent used is as follows: 20 parts by weight of N,N-diisopropylethanolamine, 60 parts by weight of hydroxyethylethylenediamine, 10 parts by weight of 2-(isopropylamino)ethanol, 8 parts by weight of N-aminoethylpiperazine and 2 parts by weight of methionine; the absorbent is configured into an absorbent solution with a mass concentration of 35%, and the other conditions are exactly the same as in Example 5.

[0110] During this process, the absorption rate of flue gas carbon dioxide is 85%, and the steam consumption for 1 ton of carbon dioxide is 1.2 tons.

[0111] Embodiment 13

[0112] The method of Example 5 is followed, except that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 11 parts by weight of piperazine and 4 parts by weight of aminoacetic acid; the absorbent is configured into an absorbent solution with a mass concentration of 35%, and the other conditions are exactly the same as in Example 5.

[0113] During this process, the absorption rate of flue gas carbon dioxide is 83%, and the steam consumption for 1 ton of carbon dioxide is 1.05 tons.

[0114] Embodiment 14

[0115] The method of Example 5 is different in that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 5 parts by weight of aminoacetic acid; the absorbent is prepared into an absorbent solution with a mass concentration of 35%. The flow rate of the absorbent solution is 45Nm 3 / h. The feed temperature of the carbon dioxide-rich solution is 80°C. The solution regeneration heat source uses low-pressure steam, the regeneration speed is 450rpm, and the regeneration pressure is 35kPaG. The other conditions are exactly the same as those in Example 5.

[0116] During this process, the absorption rate of flue gas carbon dioxide is 83%, and the steam consumption for 1 ton of carbon dioxide is 0.95 tons.

[0117] Embodiment 15

[0118] The method of Example 5 is different in that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 5 parts by weight of aminoacetic acid; the absorbent is prepared into an absorbent solution with a mass concentration of 35%. The flow rate of the absorbent solution is 45Nm 3 / h. The feed temperature of the carbon dioxide-rich solution is 95°C. The solution regeneration heat source uses low-pressure steam, the regeneration speed is 350rpm, and the regeneration pressure is 35kPaG. The other conditions are exactly the same as those in Example 5.

[0119] During this process, the absorption rate of flue gas carbon dioxide is 83%, and the steam consumption for 1 ton of carbon dioxide is 0.8 tons.

[0120] Example 16

[0121] The method of Example 5 is different in that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 5 parts by weight of aminoacetic acid; the absorbent is prepared into an absorbent solution with a mass concentration of 35%. The flow rate of the absorbent solution is 45Nm 3 / h. The feed temperature of the carbon dioxide-rich solution is 80°C. The solution regeneration heat source uses low-pressure steam, the regeneration speed is 350rpm, and the regeneration pressure is 45kPaG. The other conditions are exactly the same as those in Example 5.

[0122] During this process, the absorption rate of flue gas carbon dioxide is 83%, and the steam consumption for 1 ton of carbon dioxide is 0.85 tons.

[0123] Embodiment 17

[0124] Use Figure 1 The flue gas carbon dioxide recovery device shown in the figure, wherein the gas-liquid separation device 1 adopts a supergravity reactor, and the flue gas processing capacity is 12000Nm 3 / h, carbon dioxide content 6.5%, flue gas temperature 38 ° C, the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol, 10 parts by weight of piperazine and 5 parts by weight of aminoacetic acid; the absorbent is configured into an absorbent solution with a mass concentration of 35%. The flow rate of the absorbent solution is 45Nm 3 / h. The feed temperature of the carbon dioxide-rich solution is 80°C. The solution regeneration heat source uses low-pressure steam, the regeneration speed is 350rpm, and the regeneration pressure is 35kPaG.

[0125] In this process, the absorption rate of flue gas carbon dioxide was 83%, the steam consumption for 1 ton of carbon dioxide was 1.0 ton, and the consumption of absorbent solution after 90 days of operation was 0.76 kg / t carbon dioxide.

[0126] Comparative Example 1

[0127] The method of Example 5 is followed, except that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol and 5 parts by weight of aminoacetic acid; the absorbent is configured into an absorbent solution with a mass concentration of 35%, and the other conditions are exactly the same as in Example 5.

[0128] During this process, the absorption rate of flue gas carbon dioxide is 78%, and 1 ton of carbon dioxide steam is consumed 1.1 tons.

[0129] Comparative Example 2

[0130] The method of Example 5 is followed, except that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 10 parts by weight of piperazine and 5 parts by weight of aminoacetic acid; the absorbent is configured into an absorbent solution with a mass concentration of 35%, and the other conditions are exactly the same as in Example 5.

[0131] In this process, the absorption rate of flue gas carbon dioxide is 79%, and the steam consumption for 1 ton of carbon dioxide is 1.0 ton.

[0132] Comparative Example 3

[0133] The method of Example 5 is followed, except that the formula of the carbon dioxide absorbent used is as follows: 25 parts by weight of methyldiethanolamine, 45 parts by weight of 3-methylaminopropylamine, 15 parts by weight of 2-amino-2-methyl-1-propanol and 10 parts by weight of piperazine; the absorbent is configured into an absorbent solution with a mass concentration of 35%, and the other conditions are exactly the same as in Example 1.

[0134] In this process, the absorption rate of flue gas carbon dioxide is 81%, the steam consumption for 1 ton of carbon dioxide is 1.8 tons, and the consumption of absorbent solution after 90 days of operation is 0.95 kg / t carbon dioxide.

[0135] Comparative Example 4

[0136] The raw material conditions and process are the same as those of the above-mentioned Example 5, except that the composition and content of the carbon dioxide absorbent solution used are as follows: 35 wt % monoethanolamine and the rest is deionized water.

[0137] During the process, the absorption rate of flue gas carbon dioxide is 81%, the steam consumption for 1 ton of carbon dioxide is 2.1 tons, the carbon dioxide absorption absorbent solution consumption after 30 days of operation is 3kg / t carbon dioxide, and the absorbent solution consumption after 90 days of operation is 2.0kg / t carbon dioxide.

[0138] It can be seen from the above results that the method of the present invention has lower steam consumption and carbon dioxide absorbent solution consumption.

[0139] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A carbon dioxide absorbent, characterized in that The absorbent comprises: 15-40 parts by weight of tertiary amine, 15-70 parts by weight of polyamine, 1-20 parts by weight of hindered amine, 1-20 parts by weight of activator and 1-5 parts by weight of organic acid containing amino group.

2. The absorbent according to claim 1, wherein The tertiary amine has a structure shown in Formula I: Wherein, R1, R2 and R3 are each independently a C1-C3 alkyl or alkanol group; Preferably, the tertiary amine is selected from one or more of methyldiethanolamine, diethylethanolamine, dimethylethanolamine and N,N-diisopropylethanolamine.

3. The absorbent according to claim 1, wherein The polyamine has a structure shown in Formula II: wherein R4, R5, R6, R7 and R8 are each independently a hydrogen atom or an alkyl or alkanol group of C1 or above; Preferably, the polyamine is selected from one or more of 3-methylaminopropylamine, hydroxyethylethylenediamine and 3,3'-bis(methylamino)-N-methyldipropylamine.

4. The absorbent according to claim 1, wherein The hindered amine has a structure shown in Formula III: Among them, R9, R 10 , R 11 and R 12 are independently H, alkyl or alkanol, and R9, R 10 and R 11 At most one is H; Preferably, the hindered amine is selected from one or more of 2-amino-2-methyl-1-propanol, 1-amino-2-methyl-2-propanol, tert-butylaminoethanolamine and 2-(isopropylamino)ethanol.

5. The absorbent according to claim 1, wherein The activator has a structure shown in Formula IV: Among them, R 13 is H, C1-C3 alkyl, aminoalkyl or alkanol, R 14 and R 15 Each is independently H or a C1-C3 alkyl or alkanol group; M is a substituted or unsubstituted methylene group, a heteroatom or a group containing a heteroatom; Preferably, the activator is selected from one or more of piperazine, 2-methylpiperazine, N-methylpiperazine, N-ethylpiperazine, N-aminoethylpiperazine, piperidine and morpholine.

6. The absorbent according to claim 1, wherein The amino-containing organic acid is selected from one or more of amino acids or amino-containing sulfonic acids; preferably, the amino acid is selected from one or more of glycine, sarcosine, alanine, β-alanine, serine and methionine; Preferably, the amino group-containing sulfonic acid is selected from one or more of aminomethanesulfonic acid, 2-aminoethanesulfonic acid and 2-(methylamino)ethanesulfonic acid.

7. A method for absorbing and regenerating a carbon dioxide absorbent, characterized in that: The method comprises the following steps: contacting an absorption solution containing the carbon dioxide absorbent according to any one of claims 1 to 6 with a gas containing carbon dioxide to absorb carbon dioxide and obtain a carbon dioxide-rich solution; The carbon dioxide-rich solution is subjected to heat exchange and then gas-liquid separation to achieve regeneration of the absorption solution.

8. The method according to claim 7, wherein: The solvent of the absorption solution is water or alcohol, and the concentration of the carbon dioxide absorbent in the absorption solution is 5-50wt%, preferably 25-45wt%; and / or, in the carbon dioxide-rich solution, the concentration of carbon dioxide is 25-90 g / L, preferably 45-85 g / L; and / or, the temperature of the carbon dioxide-rich solution after heat exchange is 50-100° C., preferably 80-100° C.; And / or, the pressure of the regeneration process is -0.08 MPaG to 0.15 MPaG, preferably -0.02 MPaG to 0.12 MPaG.

9. The method according to claim 7 or 8, wherein: The method further comprises: performing gas-liquid separation on part or all of the regenerated carbon dioxide lean solution to perform deep regeneration of the absorption solution.

10. The method according to any one of claims 7 to 9, wherein: The gas-liquid separation is carried out in a gas-liquid separation device, specifically comprising the following steps: The carbon dioxide-rich solution is sent to the gas-liquid separation device after heat exchange, and the carbon dioxide gas is separated by the gas-liquid separation device; the gas generated by the separation enters the gas-liquid separation cooler, and is cooled by the gas-liquid separation cooler to obtain carbon dioxide; the regenerated carbon dioxide-lean solution flows into the buffer heating tank, and part or all of the carbon dioxide-lean solution is returned to the gas-liquid separation device through a pump to perform deep regeneration of the absorption solution.

11. The method according to claim 10, wherein: The gas-liquid flow direction of the carbon dioxide-rich solution in the gas-liquid separation device is gas-liquid countercurrent, gas-liquid cocurrent or gas-liquid baffled; And / or, the gas-liquid separation device is a rotary flash evaporator or a supergravity reactor; preferably, the rotation speed of the gas-liquid separation device is 100-1500rpm, preferably 300-1000rpm; And / or, the temperature of the buffer heating tank is 55-115°C; preferably 85-115°C; And / or, the pressure of the gas-liquid separation cooler is -0.07-0.14 MPaG.

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