An absorption solution for carbon dioxide, a method for preparing the same, and an absorption system

Abstract

The application provides an absorption solution for carbon dioxide, a preparation method and an absorption system. The absorption solution contains 13-19% of piperazine, 13-19% of 2-amino-2-methyl-1-propanol, 0.6-1.5% of a chelating agent, and the balance is water in percentage by weight. The absorption solution of the application is helpful for better utilizing the fast absorption kinetics and solvent stability of piperazine, cooperating with the absorption system for preventing piperazine crystallization, forming a new mixed amine system with high reaction speed and stability, and improving the absorption effect of the absorption solution on carbon dioxide. Moreover, the absorption solution of the embodiment has better anti-degradation capacity and longer service life, and is helpful for reducing the cost of the absorption solution.

Description

Technical Field

[0001] This invention relates to the field of carbon capture technology, and in particular to an absorption solution for carbon dioxide, a method for preparing the solution, and an absorption system thereof. Background Technology

[0002] Carbon capture is the process of capturing carbon dioxide from gases and then storing or utilizing it, with the aim of reducing carbon dioxide emissions. Common absorption systems are mainly used in the treatment of industrial flue gas. The general process flow is as follows: pretreated flue gas is fed into an absorption tower through a flue, where an absorbent solution reacts with the carbon dioxide in the flue gas, thereby removing the carbon dioxide. Therefore, the absorbent solution is a crucial component of the carbon capture process, and finding absorbent solutions with better absorption efficiency and lower costs is one of the core issues in the development of carbon capture technology. Summary of the Invention

[0003] One object of the present invention is to provide an absorption solution for carbon dioxide, a method for preparing the solution, and an absorption system thereof that help improve the absorption efficiency of carbon dioxide.

[0004] In particular, the present invention provides an absorption solution for carbon dioxide, wherein, by weight percentage, the absorption solution contains 13% to 19% piperazine, 13% to 19% 2-amino-2-methyl-1-propanol, 0.6% to 1.5% chelating agent, and the balance being water.

[0005] Optionally, the weight percentage of piperazine in the absorption solution is greater than or equal to the weight percentage of 2-amino-2-methyl-1-propanol.

[0006] Optionally, the piperazine content in the absorption solution accounts for 14% to 18% of the total weight of the absorption solution.

[0007] Optionally, the chelating agent is hydroxyethyl ethylenediamine triacetic acid, cyclohexanediaminetetraacetic acid, diethylenetriaminepentaacetic acid, or ethylenediaminetetraacetic acid, and the weight percentage of the chelating agent in the absorption solution is 0.85% to 1.35%.

[0008] In another aspect of this application, a method for preparing a carbon dioxide absorption solution according to any of the above-mentioned methods is provided, comprising: Add 2-amino-2-methyl-1-propanol to water to obtain the first solution; A chelating agent is added to the first solution to obtain a second solution; Add piperazine to the second solution to obtain a third solution containing 8% to 12% piperazine by weight; Air is bubbled into the third solution under normal temperature and pressure conditions to maintain the oxygen content of the solution at 1 mg / L to 3 mg / L for 45 to 65 hours to obtain the fourth solution. Piperazine is added to the fourth solution to obtain the absorption solution.

[0009] In another aspect of this application, an absorption system is provided, comprising: The absorption tower is equipped with a reaction chamber for receiving the gas to be treated; A spraying device, installed within the reaction chamber, is used to spray the lean absorbent solution into the reaction chamber; and A lean solution cooler, connected to the spraying device, is used to cool the lean absorbent solution flowing to the spraying device; The absorption system uses an absorption solution as described in any of the above-mentioned descriptions.

[0010] Optionally, the heat exchange surface of the lean solution side of the absorbent solution cooler is provided with a Teflon anti-scaling coating with a thickness of less than 100 micrometers.

[0011] Optionally, the outlet temperature of the lean absorbent solution in the lean cooler is configured to be greater than or equal to 40 degrees Celsius.

[0012] Optionally, the spraying device includes a delivery pipe and a plurality of spray heads, the plurality of spray heads being connected to the delivery pipe, and each spray head comprising: The connector is provided with a water passage, the two ends of which form an inlet and an outlet, respectively. The connector is connected to the conveying pipe and communicates with the conveying pipe through the inlet; and Multiple water-dispersing structures are sequentially arranged on the outlet side of the connector along the water outlet direction of the spray head. Each water-dispersing structure is provided with a water passage hole. The water passage holes of all water-dispersing structures are correspondingly arranged along the water outlet direction of the spray head, and the water passage hole of the water-dispersing structure closest to the water outlet is correspondingly arranged to the water outlet. In two adjacent water passage holes, the diameter of the water passage hole closer to the water outlet is larger than the diameter of the water passage hole farther away from the water outlet, so that the absorbent solution flowing out of the water outlet can pass through all the water passage holes in sequence and be dispersed by all the water-dispersing structures.

[0013] Optionally, each of the water-spraying structures is annular, and the diameter increases with the water outlet direction of the spray head, thereby forming a water-spraying surface that slopes outwards in all directions along the water outlet direction of the spray head. The water-spreading surface is in contact with the wall of the water passage, thereby forming a tapering structure facing the direction of the water outlet.

[0014] In typical carbon capture and absorption solution formulations, piperazine is used as a promoter, with a weight percentage not exceeding 10%, and it is not the most concentrated solute. The absorption solution of this invention, however, uses piperazine as the most concentrated solute, configured at 13%–19%, and 2-amino-2-methyl-1-propanol at 13%–19%, requiring a higher concentration of piperazine than other solutes. This system facilitates better utilization of the rapid absorption kinetics of piperazine. Furthermore, by using piperazine to stabilize the solvent and balancing it with the higher carbon dioxide loading capacity of 2-amino-2-methyl-1-propanol, a novel mixed amine system with advantages in reaction rate and stability is formed, improving the absorption efficiency of the absorption solution for carbon dioxide. Moreover, the absorption solution of this embodiment has better resistance to degradation, a longer service life, and helps reduce the cost of the absorption solution.

[0015] The method for preparing the absorption solution ensures that a large amount of piperazine can dissolve smoothly into the solvent and form a stable solution system. The third step involves air bubbling for 45 to 65 hours to ensure complete dissolution, creating favorable conditions for the dissolution of the remaining piperazine in the fourth step. Furthermore, the bubbling process achieves a trace amount of dissolved oxygen (1 mg / L to 3 mg / L), allowing the solute to form intermediates such as piperazine-N-oxygen free radicals within the solution, thus promoting the solution's adaptability to oxygen.

[0016] Furthermore, the absorption system of this invention employs an absorption solution dominated by high-concentration piperazine, which exhibits a faster absorption rate compared to traditional absorption solutions, thereby enhancing carbon dioxide treatment capacity. Moreover, by constructing a comprehensive crystallization control system, utilizing a triple protection mechanism of anti-adhesion coating on the lean solution cooler, water-spraying and breaking spray heads, and safe temperature control at the lean solution cooler outlet, the crystallization risk from the absorption tower to the lean solution cooler is systematically resolved, ensuring long-term operation of the absorption system, even with a high-concentration piperazine-dominated absorption solution. This translates the formulation characteristics into a clear and monitorable operational direction.

[0017] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0018] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic flowchart of a method for preparing an absorption solution according to an embodiment of the present invention; Figure 2This is a graph showing the absorption rate as a function of time for Example 1 and Comparative Example 1 according to an embodiment of the present invention; Figure 3 These are graphs showing the load change over time in Embodiment 1 and Comparative Example 1 according to an embodiment of the present invention. Figure 4 This is a graph showing the degradation rate of Examples 1, 1, 2 and 3 of the present invention over time. Figure 5 This is a schematic diagram of an absorption system according to an embodiment of the present invention; Figure 6 This is a schematic diagram of a spray head according to an embodiment of the present invention; Figure 7 This is a schematic cross-sectional view of a spray head according to an embodiment of the present invention. Detailed Implementation

[0019] Those skilled in the art should understand that the embodiments described below are merely a part of the embodiments of the present invention, and not all of the embodiments of the present invention. These partial embodiments are intended to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by those skilled in the art without creative effort should still fall within the scope of protection of the present invention.

[0020] In one embodiment, the carbon dioxide absorption solution contains, by weight percentage, 13% to 19% piperazine, 13% to 19% 2-amino-2-methyl-1-propanol, 0.6% to 1.5% chelating agent, and the balance being water.

[0021] Specifically, the content of piperazine can be 13%, 14%, 15%, 16%, 17%, 18%, or 19%, etc. The content of 2-amino-2-methyl-1-propanol can be 13%, 14%, 15%, 16%, 17%, 18%, or 19%, etc.

[0022] The chelating agent is hydroxyethyl ethylenediaminetriacetic acid, cyclohexanediaminetetraacetic acid, diethylenetriaminepentaacetic acid, or ethylenediaminetetraacetic acid. The chelating agent balances environmental friendliness, technological maturity, and cost. The content of the chelating agent can be 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, or 1.5%, etc.

[0023] The absorbent solution of this application, by configuring the piperazine content to 13%~19% and the 2-amino-2-methyl-1-propanol content to 13%~19%, helps to better utilize the rapid absorption kinetics of piperazine. Simultaneously, it balances this with the high carbon dioxide loading capacity of 2-amino-2-methyl-1-propanol, forming a novel mixed amine system characterized by its high reaction rate, thus improving the absorption efficiency of the absorbent solution for carbon dioxide. Furthermore, the absorbent solution of this embodiment exhibits better resistance to degradation and a longer service life, contributing to a reduction in absorbent solution costs.

[0024] Preferably, the weight percentage of piperazine in the absorption solution is greater than the weight percentage of 2-amino-2-methyl-1-propanol. This maximizes the rapid absorption capacity of piperazine.

[0025] Preferably, the piperazine content in the absorption solution accounts for 14% to 18% of the total weight of the absorption solution. For example, 14%, 15%, 16%, 17%, or 18%.

[0026] In typical carbon capture and absorption solution formulations, piperazine is used as a promoter, with an addition percentage not exceeding 10% by weight, and it is not the most concentrated solute. The absorption solution of this invention, however, requires a higher concentration of piperazine than other solutes, making piperazine the most concentrated solute. This system facilitates better utilization of the rapid absorption kinetics of piperazine. Furthermore, by using piperazine to stabilize the solvent, and simultaneously balancing this with the higher carbon dioxide loading capacity of 2-amino-2-methyl-1-propanol, a novel mixed amine system with advantages in reaction rate and stability is formed, improving the absorption efficiency of the absorption solution for carbon dioxide. Moreover, the absorption solution of this embodiment exhibits better resistance to degradation, a longer service life, and helps reduce the cost of the absorption solution.

[0027] Preferably, the chelating agent in the absorbent solution is 0.85% to 1.35% by weight. For example, 0.85%, 0.9%, 1.0%, 1.1%, 1.2%, or 1.35%.

[0028] This invention reveals that in high-concentration piperazine systems, the interaction between piperazine and chelating agents can be competitive, and the degradation products of piperazine can further complex metal ions, meaning that high concentrations of piperazine interfere with the effect of chelating agents. Therefore, a higher concentration of chelating agent is required to achieve effective oxidation inhibition.

[0029] like Figure 1 As shown, in one embodiment, the method for preparing the absorption solution described in the preceding embodiments generally includes: Step S101: Add 2-amino-2-methyl-1-propanol to water to obtain the first solution.

[0030] Step S102: Add a chelating agent to the first solution to obtain the second solution.

[0031] Step S103: Add piperazine to the second solution to obtain a third solution containing 8% to 12% piperazine by weight.

[0032] Step S104: Air is bubbled into the third solution under normal temperature and pressure conditions to maintain the oxygen content in the solution at 1 mg / L to 3 mg / L for 45 to 65 hours to obtain the fourth solution.

[0033] Step S105: Add piperazine to the fourth solution to obtain the absorption solution.

[0034] Specifically, 2-amino-2-methyl-1-propanol is first added to water, followed by a chelating agent, and then piperazine is added to form a solution with a piperazine content of 10%. After stirring evenly, air is introduced for 45 to 65 hours to maintain the oxygen content of the solution at 1 mg / L to 3 mg / L. Then, piperazine is added again to obtain an absorption solution with a piperazine content that meets the final requirements.

[0035] By adding piperazine in stages to achieve the required concentration, a large amount of piperazine is ensured to dissolve smoothly into the solvent and form a stable solution system. The third step involves air bubbling for 45 to 65 hours to ensure complete dissolution, creating favorable conditions for the dissolution of the remaining piperazine in the fourth step. Furthermore, the bubbling process achieves a trace amount of dissolved oxygen (1 mg / L to 3 mg / L), allowing the solute to form intermediates such as piperazine-N-oxygen free radicals in the solution, thus improving the solution's oxygen adaptability.

[0036] Absorption experiment: Example 1: By weight percentage, piperazine 16.0%, 2-amino-2-methyl-1-propanol 15.0%, chelating agent 0.85%, and the balance being water. During preparation, 2-amino-2-methyl-1-propanol was added to water to obtain a first solution. A chelating agent was added to the first solution to obtain a second solution. Piperazine was added to the second solution to obtain a third solution containing 8%–12% piperazine by weight. A certain amount of air was bubbled into the third solution at room temperature and pressure to maintain the oxygen content at 2 mg / L for 52 hours, yielding a fourth solution. Piperazine was added again to the fourth solution to obtain an absorbent solution.

[0037] Comparative Example 1: By weight percentage, piperazine 9.0%, 2-amino-2-methyl-1-propanol 22%, chelating agent 0.8%, balance water.

[0038] The absorption rate of the absorption solution was tested using a carbon dioxide concentration analyzer. The reaction temperature was 40℃, the initial carbon dioxide concentration was 13% (the remaining gas was nitrogen, 87%), the gas flow rate was 1L / min, and 100ml of absorption solution was used for testing and analysis.

[0039] Table 1 below shows the changes in absorption rate and load (the amount of carbon dioxide absorbed by the absorption solution) over time for Example 1 and Comparative Example 1.

[0040] Table 1 Combination Figure 2 and Figure 3 The figure shows the absorption rate and load of Example 1 and Comparative Example 1 over time. A represents Example 1, and E represents Comparative Example 1. It can be seen that the absorption rate of Example 1 is higher than that of Comparative Example 1 for most of the time, and the load of Example 1, i.e., the amount of carbon dioxide absorbed, is consistently higher than that of Comparative Example 1. Example 1 has a better carbon dioxide absorption effect than Comparative Example 1.

[0041] Degradation experiments of Example 1 and Comparative Example 1: The oxidative degradation rate of the absorption solution was tested using an oxidative degradation reactor under the conditions of 110℃ and 0.5MPa pure oxygen. Samples were taken approximately every three days for concentration analysis.

[0042] Table 2 below shows the changes in degradation rate over time for Example 1 and Comparative Example 1.

[0043] Table 2 As shown in Table 2, although the amount of chelating agent used in Comparative Example 1 was basically the same as that in Example 1, the degradation rate of Example 1 was consistently lower than that of Comparative Example 1. Example 1 exhibits better anti-degradation effects compared to Comparative Example 1.

[0044] Additionally, Comparative Example 2 and Comparative Example 3 are provided.

[0045] Comparative Example 2: By weight percentage, piperazine 22.0%, 2-amino-2-methyl-1-propanol 9%, chelating agent 0.3%, balance water.

[0046] Comparative Example 3: by weight percentage, piperazine 16.0%, 2-amino-2-methyl-1-propanol 15%, chelating agent 0.3%, balance water.

[0047] Combination Figure 4The figure shows the degradation rate of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 over time. It can be seen that, within the number of days the test was completed, Example 1 also showed better anti-degradation effects compared to Comparative Example 2 and Comparative Example 3.

[0048] like Figure 5 As shown, in one embodiment, the absorption system includes an absorption tower 100, a desorption tower 200, a spray device 300, and a lean solution cooler 400. The absorption tower 100 receives the gas to be treated and has a reaction chamber inside for receiving the gas. The desorption tower 200 receives the absorption solution after reacting with the gas to be treated, thereby desorbing the carbon dioxide absorbed in the absorption solution. The spray device 300 is disposed in the reaction chamber and sprays the lean absorption solution into the reaction chamber. The lean solution cooler 400 is connected to the spray device 300 and cools the lean absorption solution flowing towards the spray device 300.

[0049] Specifically, during the operation of the absorption system, the spray device 300 sprays the lean absorbent solution into the reaction chamber. The lean absorbent solution entering the reaction chamber reacts with the gas to be treated, absorbing carbon dioxide from the gas and becoming a rich absorbent solution. The rich absorbent solution flows out of the absorption tower 100 and is transported to the desorption tower 200. In the desorption tower 200, the carbon dioxide in the rich absorbent solution is desorbed, and the rich absorbent solution becomes a lean absorbent solution. The lean absorbent solution is then transported via the lean solution cooler 400 to the spray device 300, and then sprayed into the reaction chamber.

[0050] The lean solution cooler 400 is a common heat exchanger, with a lean absorbent solution flowing on one side and a medium exchanging heat with it on the other. Because the desorption tower 200 uses high-temperature desorption to desorb carbon dioxide from the rich absorbent solution, the resulting lean absorbent solution has a very high temperature. The medium for cooling the lean absorbent solution can be water or a lower-temperature rich absorbent solution.

[0051] Furthermore, the heat exchange surface of the lean solution side of the lean solution cooler 400 is provided with a Teflon anti-scaling coating with a thickness of less than 100 micrometers. Specifically, the flow channel surface of the lean solution cooler 400 for the flow of the lean solution is provided with a Teflon anti-scaling coating with a thickness of less than 100 micrometers. Its function is to prevent carbamate microcrystals from adhering, growing, and depositing on the heat exchange surface, thereby maintaining long-term high-efficiency heat transfer performance.

[0052] Furthermore, the outlet temperature of the lean absorbent solution in the lean cooler 400 is configured to be greater than or equal to 40 degrees Celsius. This is based on the crystallization curve of the specific absorbent solution of this application, strictly controlling the outlet temperature of the lean absorbent solution in the lean cooler 400 above the crystallization temperature point with sufficient safety margin to prevent bulk crystallization from occurring at the source. This transforms the formulation characteristics of the absorbent solution into clear and actionable process operation guidelines, enabling practical application.

[0053] Furthermore, the spraying device 300 includes a delivery pipe and multiple spray heads, which are connected to the delivery pipe. The delivery pipe receives the lean absorbent solution and then delivers it to the multiple spray heads, which spray the lean absorbent solution into the reaction chamber.

[0054] Reference Figure 6 and Figure 7 As shown, each spray head 500 includes a connector 510 and multiple water-spreading structures 520. The connector 510 is provided with a water passage 511. The two ends of the water passage 511 form an inlet 512 and an outlet 513, respectively. The connector 510 is connected to a delivery pipe and communicates with the delivery pipe through the inlet 512. Multiple water-spreading structures 520 are sequentially arranged on the outlet side of the connector 510 along the water outlet direction of the spray head 500. Each water-spreading structure 520 is provided with a water passage hole 521. The water passage holes 521 of all water-spreading structures 520 are correspondingly arranged along the water outlet direction of the spray head 500, and the water passage hole 521 of the water-spreading structure 520 closest to the outlet 513 is correspondingly arranged to the outlet 513. In two adjacent water passage holes 521, the diameter of the water passage hole 521 closer to the water outlet 513 is larger than the diameter of the water passage hole 521 farther from the water outlet 513, so that the absorbent solution flowing out of the water outlet 513 can pass through all the water passage holes 521 in sequence and be dispersed by all the water distribution structures 520.

[0055] Specifically, the connector 510 has threads on its exterior for connection to the conveying pipe. The water distribution structure 520 is annular, with a central hole serving as the water passage hole 521. The water distribution structure 520 closest to the connector 510 is connected to the connector 510, and adjacent water distribution structures 520 are connected together. It should be noted that multiple water distribution structures and the connector can also be connected using a long rod passing through all the water passage holes.

[0056] Reference Figure 6 and Figure 7 As shown, the diameter of the outlet 513 is larger than the inlet diameter of the water passage 521 of the water distribution structure 520 closest to the outlet 513. The absorbent solution flowing out of the outlet 513 can pass through the water passage 521 of each water distribution structure 520 in sequence. At the same time, each time it enters the water passage 521, some liquid will be blocked by the water distribution structure 520 and then dispersed to the surroundings by the water distribution structure 520.

[0057] Specifically, after the absorbent solution exits from the outlet 513, it is first "cut off" by the solid portion surrounding the water passage 521 of the first water distribution structure 520, removing a portion of its outer thickness. This thickness of absorbent solution then spreads along the outer surface of the water distribution structure 520, forming a spray. The remaining absorbent solution then continues to pass through the water passage 521 of the first water distribution structure 520, and is then cut off by the second water distribution structure 520, and so on.

[0058] The spray head 500 in this embodiment helps reduce the risk of clogging and improves the coverage area and distribution uniformity of the absorption solution, thereby enhancing gas-liquid contact efficiency and improving gas-liquid reaction efficiency.

[0059] like Figure 6 and Figure 7 As shown, each water-diffusing structure 520 is annular, and its diameter increases with the water outlet direction of the spray head 500, thus forming a water-diffusing surface that slopes outwards in all directions along the water outlet direction of the spray head 500. Specifically, the outer peripheral surface of the water-diffusing structure 520 is the outer peripheral surface of a frustum, and the outer peripheral surface of the water-diffusing structure 520 constitutes the water-diffusing surface.

[0060] By making the water distribution structure annular with its diameter increasing along the water outlet direction of the spray head 500, a water distribution surface sloping outwards along the water outlet direction of the spray head 500 is formed. This not only achieves the dispersed spraying of the absorbent solution but also helps ensure the smooth flow of the absorbent solution, reduces resistance, avoids spray energy loss, and thus obtains a better spraying effect. Furthermore, it can prevent crystal deposition.

[0061] It should be noted that in some other embodiments, the water distribution structure may also be a perforated flat plate structure or a perforated frustum structure.

[0062] like Figure 6 and Figure 7 As shown, along the water outlet direction of the spray head 500, the angle between the water-spreading surface of the water-spreading structure 520 and the axis of the water outlet 513 gradually decreases. For example... Figure 7 As shown in the diagram, the vertical dashed line represents the axis of the outlet 513, and the three slanted dashed lines represent the extensions of the water-spreading surfaces of the three water-spreading structures 520. Angles a, b, and c in the diagram represent the angles between the water-spreading surfaces of the three water-spreading structures 520 and the axis of the outlet 513. Along the water outlet direction of the sprinkler head 500, the angles between the water-spreading surfaces of the water-spreading structures 520 and the axis of the outlet 513 gradually decrease, meaning angle a is greater than angle b, which is greater than angle c.

[0063] By making the angle between the water distribution surface of the water distribution structure 520 and the axis of the water outlet 513 gradually smaller along the water outlet direction of the spray head 500, it helps the spray head 500 to form a layered coverage area, ensuring the uniformity of the absorption solution distribution within the coverage area, which is beneficial to improving the efficiency of gas-liquid reaction.

[0064] like Figure 7 As shown, the diameter of each water passage 521 decreases along the water outlet direction of the spray head 500. This structure helps to accelerate the flow of the absorbent solution within the water passage 521, enhances the dynamics of the absorbent solution, and thus ensures that the absorbent solution has a greater impact force on each water distribution structure 520, thereby increasing the range of outward diffusion of the absorbent solution.

[0065] like Figure 7 As shown, the water-spreading surface is in contact with the wall of the water passage 521, thus forming a tapering structure towards the outlet 513. This is a sharp-angled structure towards the outlet 513, which allows the crystals carried by the high-pressure liquid flow to be broken by impact, preventing crystal accumulation and blockage on the water-spreading structure 520 and ensuring uniform distribution of the absorbent solution. Furthermore, to achieve better cutting results, the chamfer radius of the sharp angle formed at the junction of the water-spreading surface and the wall of the water passage 521 is less than 0.3 mm.

[0066] The absorption system in this embodiment uses an absorbent solution dominated by high-concentration piperazine, which has a faster absorption rate and improves carbon dioxide treatment capacity compared to traditional absorbent solutions. Furthermore, by constructing a full-process crystallization control system, utilizing the anti-adhesion coating of the lean liquid cooler 400, the water-spraying and breaking spray head 500, and the safety control of the outlet temperature of the lean liquid cooler 400, the crystallization risk from the absorption tower 100 to the lean liquid cooler 400 is systematically resolved, ensuring long-term operation of the absorption system, even with a high-concentration piperazine-dominated absorbent solution. This translates the formulation characteristics into a clear and monitorable operational direction.

[0067] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A solution for absorbing carbon dioxide, characterized in that, The absorbent solution contains, by weight percentage, 13% to 19% piperazine, 13% to 19% 2-amino-2-methyl-1-propanol, 0.6% to 1.5% chelating agent, and the balance being water.

2. The carbon dioxide absorption solution according to claim 1, characterized in that, The weight percentage of piperazine in the absorption solution is greater than or equal to the weight percentage of 2-amino-2-methyl-1-propanol.

3. The carbon dioxide absorption solution according to claim 2, characterized in that, The piperazine content in the absorption solution accounts for 14% to 18% of the total weight of the absorption solution.

4. The carbon dioxide absorption solution according to claim 3, characterized in that, The chelating agent is hydroxyethyl ethylenediamine triacetic acid, cyclohexanediaminetetraacetic acid, diethylenetriaminepentaacetic acid, or ethylenediaminetetraacetic acid, and the weight percentage of the chelating agent in the absorption solution is 0.85% to 1.35%.

5. A method for preparing a carbon dioxide absorption solution according to any one of claims 1 to 4, characterized in that, include: Add 2-amino-2-methyl-1-propanol to water to obtain the first solution; A chelating agent is added to the first solution to obtain a second solution; Add piperazine to the second solution to obtain a third solution containing 8% to 12% piperazine by weight; Air is bubbled into the third solution under normal temperature and pressure conditions to maintain the oxygen content of the solution at 1 mg / L to 3 mg / L for 45 to 65 hours to obtain the fourth solution. Piperazine is added to the fourth solution to obtain the absorption solution.

6. An absorption system, characterized in that, include: The absorption tower is equipped with a reaction chamber for receiving the gas to be treated; A spraying device is installed inside the reaction chamber for spraying the absorbent solution into the reaction chamber. and A lean solution cooler, connected to the spraying device, is used to cool the lean absorbent solution flowing to the spraying device; The absorption system uses the absorption solution as described in any one of claims 1 to 4.

7. The absorption system according to claim 6, characterized in that, The heat exchange surface of the lean solution side of the absorbent solution cooler is provided with a Teflon anti-scaling coating with a thickness of less than 100 micrometers.

8. The absorption system according to claim 6, characterized in that, The outlet temperature of the lean absorbent solution in the lean cooler is configured to be greater than or equal to 40 degrees Celsius.

9. The absorption system according to claim 6, characterized in that, The spraying device includes a delivery pipe and a plurality of spray heads, the plurality of spray heads being connected to the delivery pipe, and each spray head comprising: The connector is provided with a water passage, the two ends of which form an inlet and an outlet, respectively. The connector is connected to the conveying pipe and communicates with the conveying pipe through the inlet; and Multiple water-dispersing structures are sequentially arranged on the outlet side of the connector along the water outlet direction of the spray head. Each water-dispersing structure is provided with a water passage hole. The water passage holes of all water-dispersing structures are correspondingly arranged along the water outlet direction of the spray head, and the water passage hole of the water-dispersing structure closest to the water outlet is correspondingly arranged to the water outlet. In two adjacent water passage holes, the diameter of the water passage hole closer to the water outlet is larger than the diameter of the water passage hole farther away from the water outlet, so that the absorbent solution flowing out of the water outlet can pass through all the water passage holes in sequence and be dispersed by all the water-dispersing structures.

10. The absorption system according to claim 9, characterized in that, Each of the aforementioned water-spraying structures is annular, and its diameter increases with the direction of water discharge from the spray head, thereby forming a water-spraying surface that slopes outwards in all directions along the direction of water discharge from the spray head. The water-spreading surface is in contact with the wall of the water passage, thereby forming a tapering structure facing the direction of the water outlet.

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