Method and apparatus for removal of iron ions from carbon capture absorbents

Abstract

The present application relates to the technical field of carbon capture, in particular to a method and device for removing iron ions in carbon capture absorbent, the method comprises the following steps: transmitting the absorption liquid to a removal container; determining the adding speed of the reducing agent according to the concentration of the ferric ions in the absorption liquid and the flow rate parameter of the absorption liquid; reducing part of the ferric ions to ferrous ions; adding the alkali solution to the removal container when the concentration of the ferric ions in the absorption liquid is reduced to the preset concentration; reacting the ferric ions and the ferrous ions with the alkali solution to generate the precipitate; stopping adding the alkali solution to the absorption liquid when the PH value of the absorption liquid is adjusted to the preset range; and discharging the precipitate, the method for removing the iron ions in the carbon capture absorbent can remove the iron ions in the absorbent and improve the performance of the absorbent.

Description

Technical Field

[0001] This invention relates to the field of carbon capture technology, and specifically to a method and apparatus for removing iron ions from a carbon capture absorbent. Background Technology

[0002] During the long-term operation of carbon capture systems, corrosion gradually emerges due to the interaction of complex factors such as the reaction between the absorbent and carbon dioxide in the flue gas, the high-temperature conditions of the system, and the gradual degradation of reaction products. During this corrosion process, the ferrous components are gradually eroded, resulting in a large amount of impurity iron ions in the absorbent, which affects its performance. Related technologies often employ adsorption filtration for removal; however, adsorption filtration is ineffective at removing ferric ions from the solution, thus impacting the absorbent's performance. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a method for removing iron ions from a carbon capture absorbent, which can remove iron ions from the absorbent and improve its performance.

[0004] The present invention also proposes a device for removing iron ions from a carbon capture absorbent.

[0005] The method for removing iron ions from a carbon capture absorbent according to embodiments of the present invention includes:

[0006] The absorbent is transferred to the removal container;

[0007] The addition rate of the reducing agent is determined based on the concentration of ferric ions in the absorbent and the flow rate parameters of the absorbent, and some of the ferric ions are reduced to ferrous ions.

[0008] When the concentration of ferric ions in the absorbent is reduced to a preset concentration, an alkaline solution is added to the removal container, and the ferric ions and ferrous ions react with the alkaline solution to form a precipitate.

[0009] When the pH value of the absorption liquid is adjusted to a preset range, the addition of alkali solution to the absorption liquid is stopped;

[0010] The precipitate is then discharged.

[0011] The method for removing iron ions from the carbon capture absorbent of this invention can remove iron ions from the absorbent and improve the performance of the absorbent.

[0012] In some embodiments, determining the addition rate of the reducing agent based on the concentration of ferric ions in the absorbent and the flow rate parameter of the absorbent includes:

[0013] The flow rate V of the absorbent liquid flowing towards the removal container is measured.

[0014] The area of ​​the pipe cross-section at the measurement location of the flow velocity is calculated as A;

[0015] The concentration of ferric ions in the absorption solution was measured to be c. Fe 3+ ;

[0016] Determine the number of electrons lost by one molecule of reducing agent during the reaction with ferric ions as N;

[0017] The rate at which the reducing agent is added is calculated to be R, and

[0018] In some embodiments, when the concentration of ferric ions in the absorbent decreases to a preset concentration, an alkaline solution is added to the removal container, and the ferric ions and ferrous ions react with the alkaline solution to form a precipitate, including:

[0019] The real-time concentration of ferric ions in the absorption solution is measured as c;

[0020] In c = 2 / 3 × c Fe 3+ At that time, an alkaline solution is added to the removal container using an electronically controlled valve;

[0021] The alkaline solution reacts simultaneously with the ferric ions (Fe3+) and the ferrous ions (Fe2+), and the reaction is as follows: Fe 2+ +2Fe 3+ +8OH - →Fe3O4↓4H2O, the precipitate is iron(III) oxide.

[0022] In some embodiments, when the pH value of the absorbent is adjusted to a preset range, stopping the addition of alkali solution to the absorbent includes:

[0023] The real-time pH value of the absorbent in the removal container is measured to be P;

[0024] When 10≤P≤12, the electrically controlled valve is closed.

[0025] In some embodiments, the absorbent is a circulating absorbent, and the removal container is provided with an inlet pipe and an outlet pipe arranged opposite to each other. The inlet pipe is adapted to be connected to the desorption tower, and the outlet pipe is adapted to be connected to the absorption tower.

[0026] In some embodiments, the removal container is provided with a plurality of magnetic rods arranged in a matrix, the magnetic rods being detachably connected to the removal container, and the magnetic rods being able to adsorb the precipitate.

[0027] The iron ion removal device in the carbon capture absorbent of this invention includes:

[0028] Remove the container;

[0029] An inlet pipe and an outlet pipe are arranged opposite each other in the radial direction of the removal container. The inlet pipe is adapted to be connected to the desorption tower to transfer absorbent into the removal container, and the outlet pipe is adapted to be connected to the absorption tower to discharge absorbent from the removal container.

[0030] An electrically controlled valve is disposed on the removal container. The electrically controlled valve has a first state and a second state. In the first state, the electrically controlled valve is used to add a reducing agent to the removal container so that some of the ferric ions in the absorption liquid are reduced to ferrous ions. In the second state, the electrically controlled valve is used to add an alkaline solution to the removal container. The alkaline solution reacts with the ferric ions and the ferrous ions in the absorption liquid to generate a precipitate.

[0031] A magnetic rod is located inside the removal container and is used to adsorb the precipitate.

[0032] The iron ion removal device in the carbon capture absorbent of this invention can improve the performance of the absorbent.

[0033] In some embodiments, the removal device further includes a cover, wherein the top opening of the removal container is provided, and the cover covers the removal container.

[0034] In some embodiments, the cover is provided with an inlet, and one end of the electrically controlled valve is connected to the cover and communicates with the removal container through the inlet.

[0035] In some embodiments, there are multiple magnetic rods arranged in a matrix, and the magnetic rods are detachably connected to the bottom of the cover or the removal container. Attached Figure Description

[0036] Figure 1 This is a schematic flowchart of a method for removing iron ions from a carbon capture absorbent according to an embodiment of the present invention.

[0037] Figure 2 This is a schematic diagram of the iron ion removal device in the carbon capture absorbent according to an embodiment of the present invention.

[0038] Figure 3 This is a schematic diagram from another perspective of the iron ion removal device in the carbon capture absorbent according to an embodiment of the present invention.

[0039] Figure label:

[0040] Remove container 1, inlet pipe 2, outlet pipe 3, magnetic rod 4, cap 5, and inlet 51. Detailed Implementation

[0041] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0042] This invention provides a method for removing iron ions from a carbon capture absorbent, comprising: transferring an absorbent to a removal container; determining the addition rate of a reducing agent based on the concentration of ferric ions in the absorbent and the flow rate parameters of the absorbent, wherein some ferric ions are reduced to ferrous ions; when the concentration of ferric ions in the absorbent decreases to a preset concentration, adding an alkaline solution to the removal container, wherein ferric ions and ferrous ions react with the alkaline solution to form a precipitate; stopping the addition of alkaline solution to the absorbent when the pH value of the absorbent is adjusted to a preset range; and discharging the precipitate.

[0043] It should be noted that carbon dioxide is an acidic gas. When carbon dioxide reacts chemically with organic amine compounds, it forms a weakly acidic solution. The carbon dioxide capture system captures and absorbs carbon dioxide through organic amines. During the carbon capture process, a large amount of iron ions, impurities, are present in the absorbent. These iron ions hinder the effective reaction between the absorbent and carbon dioxide and accelerate the degradation process of the organic amine absorbent. This not only reduces the effectiveness of the absorbent but may also generate more corrosive substances, exacerbating equipment corrosion and producing more iron ion impurities. This embodiment describes a method for removing iron ions from the absorbent of a carbon dioxide capture system to reduce the iron ion content in the absorbent, thereby ensuring the efficient, safe, and stable operation of the carbon capture system.

[0044] Specifically, such as Figure 1 As shown, in this embodiment, an absorbent containing ferric ions is transferred to a removal container, and a reducing agent is added to the removal container. It can be understood that the iron ions dissolved in the solution are generally ferric ions. Under the action of the reducing agent, the ferric ions are reduced to ferrous ions. By real-time detection of the concentration of ferric ions in the absorbent, when the concentrations of ferric ions and ferrous ions in the absorbent reach the required concentrations, an alkaline solution is added to the removal container to create an alkaline environment. The ferric ions and ferrous ions in the absorbent react with the alkaline solution to generate a precipitate, thereby removing the iron ions from the absorbent.

[0045] Optionally, in this embodiment, the removal device is located between the absorption tower and the desorption tower, that is, on the pipeline between the lean liquid flowing out of the desorption tower and the absorption tower. Before entering the absorption tower, the lean liquid absorbent contains less carbon dioxide, so as to avoid the reducing agent and alkaline solution affecting the carbon dioxide. Moreover, after the lean liquid exchanges heat with the rich liquid, the temperature of the lean liquid is not high, and the reaction between iron ions and the reducing agent and alkaline solution is not so violent, which is relatively safer, the effect of removing iron ions is better, and the impact on the absorbent is smaller.

[0046] For example, the reducing agent is sodium thiosulfate or sodium sulfite.

[0047] For example, flow rate parameters include the flow rate of the absorbent towards the removal container, the cross-sectional area of ​​the pipe at the flow rate measurement location, and the number of electrons lost by a molecule of reducing agent during its reaction with ferric ions.

[0048] The method for removing iron ions from the carbon capture absorbent of this invention involves adding a reducing agent to the absorbent to reduce the valence of iron ions dissolved in the absorbent, and then adding an alkaline solution to the absorbent. By adjusting the chemical ratio of the reducing agent and the alkaline solution, the iron ions in the absorbent are co-precipitated with the alkaline solution to form solid iron particles. This not only removes the iron ions from the absorbent but also prevents them from participating in the degradation process of the absorbent, thereby slowing down the aging rate of the absorbent and improving the performance of the absorbent.

[0049] Furthermore, in this embodiment, the solid iron particles generated by the co-precipitation of iron ions and alkaline solution are discharged outside the removal container by filtration or magnetic adsorption, thereby removing iron ions and iron particles generated in the absorbent. Combining chemical and physical methods not only improves the removal efficiency but also simplifies operation and is cost-effective. Moreover, by reducing the iron ion content in the absorbent, the long-term operating performance of the absorbent can be significantly improved, while reducing the risk of equipment corrosion. This improves the collection efficiency, operational safety, and stability of the carbon capture system.

[0050] In some embodiments, determining the addition rate of the reducing agent based on the concentration of ferric ions in the absorbent and the flow rate parameter of the absorbent includes: measuring the flow rate of the absorbent towards the removal container as V; calculating the cross-sectional area of ​​the pipe at the flow rate measurement location as A; and measuring the concentration of ferric ions in the absorbent as c. Fe 3+ Determine the number of electrons lost by one molecule of reducing agent during the reaction with ferric ions as N; calculate the rate of addition of the reducing agent as R, and...

[0051] Specifically, in this embodiment, the addition rate of the reducing agent is calculated by taking into account the flow rate of the absorbent entering the removal container, the cross-sectional area of ​​the pipe at the flow rate measurement location, the concentration of ferric ions in the absorbent, and the number of electrons lost by one molecule of reducing agent. The addition rate of the reducing agent is correlated with the iron ions in the absorbent, which is beneficial to the reaction between the reducing agent and ferric ions and improves the reaction efficiency between the reducing agent and ferric ions.

[0052] Furthermore, in this embodiment, the removal container is positioned between the absorption tower and the desorption tower, that is, the removal container is embedded in the circulation process of the rich and poor solutions. Since the absorption liquid is constantly circulating, by limiting the addition rate of the reducing agent, it is easier for the reducing agent to react with the ferric ions, thereby improving the uniformity of the distribution of ferrous ions in the absorption liquid.

[0053] For example, the concentration of ferric ions is expressed in mol / m³. 3 The flow rate of the absorbent is measured in m / min, and the cross-sectional area of ​​the pipe at the flow rate measurement location is m². 2 The rate at which the reducing agent is added is mol / min.

[0054] For example, when the reducing agent is sodium thiosulfate, one molecule of the reducing agent loses 1 electron during the reaction with ferric ions; when the reducing agent is sodium sulfite, one molecule of the reducing agent loses 2 electrons during the reaction with ferric ions. Sodium sulfite is used in this embodiment.

[0055] In some embodiments, when the concentration of ferric ions in the absorbent decreases to a preset concentration, an alkaline solution is added to the removal container. Ferric and divalent ions react with the alkaline solution to form a precipitate. This includes: measuring the real-time concentration of ferric ions in the absorbent as c; and then, when c = 2 / 3 × c... Fe 3+ At that time, an alkaline solution is added to the removal container using an electrically controlled valve; the alkaline solution reacts simultaneously with ferric ions and ferrous ions, and the reaction is as follows:

[0056] Fe 2+ +2Fe 3+ +8OH - →Fe3O4↓+4H2O, the precipitate is iron(III) oxide.

[0057] Specifically, under the action of the reducing agent, the ferric ions in the absorbent are reduced to ferrous ions. When 1 / 3 of the ferric ions have become ferrous ions, an alkaline solution is added to the removal container. By limiting the concentration of ferric and ferrous ions in the absorbent, only when ferric and ferrous ions participate in the reaction together will a precipitate of magnetite (Fe3O4) be formed. This facilitates the simultaneous reaction of the alkaline solution with both ferric and ferrous ions, causing the iron ions to co-precipitate in the form of ferromagnetic magnetite (Fe3O4).

[0058] Optionally, the reaction of ferric ions under the action of a reducing agent is Fe 3+ +e - →Fe 2+ .

[0059] For example, the concentration of ferric ions can be detected by ion chromatography, with the preset concentration being 2 / 3 of the original ferric ions in the absorption solution.

[0060] In some embodiments, when the pH value of the absorbent is adjusted to a preset range, the addition of alkali solution to the absorbent is stopped, including:

[0061] The real-time pH value of the absorbent in the removal container is measured as P;

[0062] When 10≤P≤12, the electrically controlled valve is closed.

[0063] Specifically, an alkaline solution is added to the removal container. The alkaline environment facilitates the reaction between hydroxide ions in the alkaline solution and ferric and ferrous ions. As the alkaline solution is continuously added, the pH value of the absorbent solution rises continuously under the action of the alkaline solution until the pH value of the alkaline solution is within the preset range of 10-12. At this point, the electric control valve is closed, and the addition of alkaline solution to the removal container is stopped. The amount of alkaline solution added is limited by the pH value of the absorbent solution, which facilitates the reaction between the ferric ions in the absorbent solution and the alkaline solution.

[0064] For example, the amount of alkali added is 5-10 times the amount of reducing agent added.

[0065] In some embodiments, the absorbent is a circulating absorbent, and the removal container is provided with an inlet pipe and an outlet pipe arranged opposite to each other. The inlet pipe is adapted to be connected to the stripping tower, and the outlet pipe is adapted to be connected to the absorption tower.

[0066] Specifically, such as Figure 2 and Figure 3As shown, the inlet pipe is located on the left side of the removal container, and the outlet pipe is located on the right side of the removal container. One end of the inlet pipe is connected to the desorption tower, and the other end of the inlet pipe is connected to the removal container to transfer the desorbed lean liquid into the removal container. One end of the outlet pipe is connected to the removal container, and the other end of the outlet pipe is connected to the absorption tower to transfer the lean liquid in the removal container into the absorption tower. The removal container is integrated into the carbon dioxide capture system through the arrangement of the inlet and outlet pipes.

[0067] This embodiment achieves effective integration by directly embedding into the carbon capture system without modifying the carbon capture system, thus achieving a significant removal effect of iron ions. This embodiment does not limit the embedding position; it can be placed after the desorption tower and before the absorption tower. As long as the removal method of iron ions in the absorbent is to use reduction precipitation or ferromagnetic adsorption, it is within the protection scope of this embodiment.

[0068] In some embodiments, the removal container is provided with a plurality of magnetic rods arranged in a matrix. The magnetic rods are detachably connected to the removal container and can adsorb precipitates.

[0069] Specifically, such as Figure 2 and Figure 3 As shown, the outer contour of the magnetic rod on the projection plane orthogonal to the left-right and front-back directions is rectangular. Since the precipitate in this embodiment is iron(III) oxide, and iron(III) oxide is magnetic, it can be adsorbed onto the outside of the magnetic rod. In this embodiment, by introducing the magnetic rod, the reaction precipitate in the absorbent can be adsorbed and separated, thereby improving the removal efficiency.

[0070] Furthermore, the arrangement of multiple magnetic rods can also create a barrier for the absorbent liquid, reducing the flow rate of the absorbent liquid in the removal container, increasing the contact time between the reducing agent and the alkaline solution and the absorbent liquid, and improving the removal efficiency of iron ions.

[0071] For example, the outer contour of a magnetic rod on a projection plane orthogonal to the left-right and front-back directions is circular.

[0072] For example, the magnetic rod is a neodymium iron boron magnet or an electromagnet.

[0073] The iron ion removal device in the carbon capture absorbent of this invention includes a removal container 1, an inlet pipe 2, an outlet pipe 3, an electrically controlled valve (not shown in the figure), and a magnetic rod 4. The inlet pipe 2 and the outlet pipe 3 are arranged opposite each other in the radial direction of the removal container 1. The inlet pipe 2 is adapted to be connected to a stripping tower to transfer absorbent into the removal container 1, and the outlet pipe 3 is adapted to be connected to an absorption tower to discharge absorbent from the removal container 1. The electrically controlled valve is located on the removal container 1 and has a first state and a second state. In the first state, the electrically controlled valve is used to add a reducing agent to the removal container 1 to reduce some of the ferric ions in the absorbent to ferrous ions. In the second state, the electrically controlled valve is used to add an alkaline solution to the removal container 1, where the alkaline solution reacts with the ferric and ferrous ions in the absorbent to form a precipitate. The magnetic rod 4 is located inside the removal container 1 and is used to adsorb the precipitate.

[0074] Specifically, such as Figure 1 As shown, Figure 2 and Figure 3 As shown, the outer contour of the removal container 1 on the projection plane orthogonal to the left-right and front-back directions is circular. After the absorbent enters the removal container 1 from the inlet pipe 2, the flow rate of the absorbent will slow down, which facilitates the reaction of the absorbent with the reducing agent and alkali solution in the removal container 1.

[0075] The inlet pipe 2 is located on the left side of the removal container 1, and the outlet pipe 3 is located on the right side of the removal container 1. One end of the inlet pipe 2 is connected to the desorption tower, and the other end of the inlet pipe 2 is connected to the removal container 1 to transfer the desorbed lean liquid into the removal container 1. One end of the outlet pipe 3 is connected to the removal container 1, and the other end of the outlet pipe 3 is connected to the absorption tower to transfer the lean liquid in the removal container 1 into the absorption tower. The removal container 1 is integrated into the carbon dioxide capture system through the arrangement of the inlet pipe 2 and the outlet pipe 3.

[0076] In this embodiment of the invention, the absorbent is transferred to the removal container 1 through the inlet pipe 2, and then discharged from the removal container 1 through the outlet pipe 3. The removal device is embedded in the carbon capture system. By adjusting the electric control valve to the first state, a reducing agent is added to the removal container 1. Under the action of the reducing agent, some of the ferric ions are converted into ferrous ions. When the concentration of ferric ions in the absorbent is at a preset concentration, the electric control valve is adjusted to the second state to add an alkaline solution to the removal container 1. The alkaline solution reacts with the ferric ions and ferrous ions to form a precipitate. Finally, the precipitate is adsorbed by the magnetic rod 4. The iron ions in the carbon capture absorbent are removed by coupling the chemical precipitant and the magnetic adsorption.

[0077] Furthermore, this embodiment effectively removes iron ions from the carbon dioxide capture absorbent by coupling chemical reduction precipitation and magnetic attraction. The dissolved iron ions are converted into a solid form that can be magnetically separated by chemical reduction reaction, and then separated from the absorbent by magnetic attraction, thereby achieving the purpose of purifying the absorbent, extending its service life and improving carbon capture efficiency.

[0078] Furthermore, in this embodiment, the removal device is embedded in the circulation pipe of the absorbent liquid in the carbon capture system as a flow-type removal device, thereby removing iron ions from the absorbent liquid without affecting the normal operation of the carbon capture system.

[0079] In some embodiments, the removal device further includes a cover 5, which has a top opening on the removal container 1 and covers the removal container 1.

[0080] Specifically, the cover 5 is designed to seal the removal device, preventing dust in the air from entering the absorption liquid, and the cover 5 also facilitates cleaning of the removal container 1.

[0081] In some embodiments, the cover 5 is provided with an inlet 51, and one end of the electric control valve is connected to the cover 5 and communicates with the removal container 1 through the inlet 51.

[0082] Specifically, such as Figure 2 and Figure 3 As shown, reducing agent and alkali solution are added into removal container 1 through inlet 51. The electric control valve facilitates the control of the volume and amount of reducing agent and alkali solution added into removal container 1, thereby improving the reaction accuracy.

[0083] The removal device of this invention introduces the carbon capture absorbent into the removal container 1, with an opening on the cover plate above the removal container 1. The amount and rate of addition of the reducing agent and alkaline solution are controlled by an electronically controlled valve. Under the action of the reducing agent, some ferric ions are converted into ferrous ions. Under the action of the alkaline solution, the ferric ions and ferrous ions react with the alkaline solution to form precipitates. The iron ions are co-precipitated in the form of ferromagnetic iron(III) oxide, which is then adsorbed by the high-strength magnetic rod 4. By using the magnetic rod 4 to adsorb the iron-containing precipitates in the carbon capture absorbent, the iron impurity content in the carbon capture absorbent is reduced, thereby reducing absorbent degradation and increasing the stability of long-term operation.

[0084] In some embodiments, there are multiple magnetic rods 4, which are arranged in a matrix and are detachably connected to the bottom of the cover 5 or the removal container 1.

[0085] Specifically, the arrangement of multiple magnetic rods 4 can also form a barrier to the absorbent liquid, reduce the flow rate of the absorbent liquid in the removal container 1, increase the contact time between the reducing agent and the alkaline solution and the absorbent liquid, and improve the removal efficiency of iron ions.

[0086] For example, the magnetic rod 4 can be detachably connected to the cover 5 or the bottom of the removal container 1 by means of flange, clamp, bolt plate or other means that can quickly release the clip. After running for a period of time, the magnetic rod 4 can be removed for regular cleaning and reuse.

[0087] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0088] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0089] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0090] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0091] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0092] It is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for removing iron ions from a carbon trap absorbent using an iron ion removal device, characterized in that, The removal device is directly embedded in the carbon capture system, allowing for effective integration without requiring modification of the carbon capture system. The removal device includes a removal container, an inlet pipe, an outlet pipe, an electrically controlled valve, and a magnetic rod. The inlet pipe and the outlet pipe are arranged opposite each other in the radial direction of the removal container. The inlet pipe is adapted to connect to a desorption tower to transfer absorbent into the removal container, and the outlet pipe is adapted to connect to an absorption tower to discharge absorbent from the removal container. The absorbent is a circulating absorbent. The removal device is located on the pipeline between the desorption tower and the absorption tower, where lean liquid flows out. The electrically controlled valve is mounted on the removal container. The electrically controlled valve has a first state and a second state. In the first state, the electrically controlled valve is used to add a reducing agent to the removal container to reduce some of the ferric ions in the absorption liquid to ferrous ions. In the second state, the electrically controlled valve is used to add an alkaline solution to the removal container. The alkaline solution reacts with the ferric ions and ferrous ions in the absorption liquid to generate a precipitate. The magnetic rod is located inside the removal container and is used to adsorb the precipitate. The removal method includes: The absorbent is transferred to the removal container; The addition rate of the reducing agent is determined based on the concentration of ferric ions in the absorbent and the flow rate parameters of the absorbent, wherein some of the ferric ions are reduced to ferrous ions. When the concentration of ferric ions in the absorbent is reduced to a preset concentration, an alkaline solution is added to the removal container, and the ferric ions and ferrous ions react with the alkaline solution to form a precipitate. When the pH value of the absorption liquid is adjusted to a preset range, the addition of alkali solution to the absorption liquid is stopped; The precipitate is then discharged.

2. The method for removing iron ions from a carbon trap absorbent according to claim 1, characterized in that, The step of determining the addition rate of the reducing agent based on the concentration of ferric ions in the absorbent and the flow rate parameters of the absorbent includes: The flow rate V of the absorbent liquid flowing towards the removal container is measured. The area of ​​the pipe cross-section at the measurement location of the flow velocity is calculated as A; The concentration of ferric ions in the absorption solution was measured to be: ; Determine the number of electrons lost by one molecule of reducing agent during the reaction with ferric ions as N; The rate at which the reducing agent is added is calculated to be R, and .

3. The method for removing iron ions using a carbon capture absorbent according to claim 2, characterized in that, When the concentration of ferric ions in the absorbent decreases to a preset concentration, an alkaline solution is added to the removal container. The ferric ions and ferrous ions react with the alkaline solution to form a precipitate, including: The real-time concentration of ferric ions in the absorption solution is measured as c; In c=2 / 3× At that time, an alkaline solution is added to the removal container using an electronically controlled valve; The alkaline solution reacts simultaneously with the ferric ions and the ferrous ions, and the reaction is as follows: The precipitate is iron(III) oxide.

4. The method for removing iron ions using a carbon capture absorbent according to claim 3, characterized in that, When the pH value of the absorbent is adjusted to a preset range, the addition of alkali solution to the absorbent is stopped, including: The real-time pH value of the absorbent in the removal container is measured to be P; When 10≤P≤12, the electrically controlled valve is closed.

5. The method for removing iron ions using a carbon capture absorbent according to claim 3, characterized in that, The removal container is equipped with a plurality of magnetic rods arranged in a matrix. The magnetic rods are detachably connected to the removal container and can adsorb the precipitate.

6. The method for removing iron ions from a carbon trap absorbent according to claim 1, characterized in that, It also includes a lid, wherein the top opening of the removal container is provided, and the lid covers the removal container.

7. The method for removing iron ions from a carbon trap absorbent according to claim 6, characterized in that, The cover is provided with an inlet, and one end of the electrically controlled valve is connected to the cover and communicates with the removal container through the inlet.

8. The method for removing iron ions using a carbon trap absorbent according to claim 6, characterized in that, The number of magnetic rods is multiple, and the multiple magnetic rods are distributed in a matrix. The magnetic rods are detachably connected to the bottom of the cover or the removal container.

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