Decarburized amine solution electrodialysis desalination purification regeneration method

Abstract

The invention discloses a decarburized amine solution electrodialysis desalination purification regeneration method. The decarburized amine solution electrodialysis desalination purification regeneration method comprises the following steps: pretreating a decarburized amine solution to obtain a pretreated solution; and performing electrodialysis purification treatment on the pretreatment solution. According to the decarburized amine solution electrodialysis desalination purification regeneration method, the ideas of electrodialysis and a membrane contactor assembly are combined, and decoloring purification of the decarburized amine solution and efficient recovery of amine are achieved.

Description

Technical Field

[0001] This application relates to the fields of chemistry and purification technology, and in particular to a method for desalination, purification and regeneration of decarbonized amine solutions via electrodialysis. Background Technology

[0002] With the deepening of the "carbon peaking and carbon neutrality" initiative, carbon capture, utilization and storage (CCUS) technology has become a key approach to reducing industrial carbon emissions. Among them, post-combustion capture technology based on amine chemical absorption is currently the most mature and widely used solution. However, amine liquids face a serious common problem during long-term recycling: degradation and volatilization.

[0003] Decarbonized amine solutions such as MEA and MDEA require desorption and regeneration at high temperatures after absorbing CO2. O2 and SO2 are inevitably present in this process and within the system. X NO X Impurities such as formaldehyde and amines cause oxidation, thermal degradation, and chemical degradation of amine molecules, producing a series of heat-stable salts (HSS) and macromolecular organic degradation products. Heat-stable salts, such as formate, acetate, sulfate, and oxalate, form strong ionic bonds with amine molecules due to their anions, making them impossible to decompose by heating in conventional regeneration towers. Consequently, they accumulate continuously in the system. This accumulation of degradation products not only reduces the absorption capacity and reaction kinetics of the amine solution, leading to increased system energy consumption, but is also a major cause of equipment corrosion, amine foaming, and severe discoloration of the amine solution (turning dark brown or bluish-black). The discoloration of the amine solution is not only a direct indicator of performance degradation but also foreshadows a decline in the reliability and economy of the entire system.

[0004] Traditional methods for removing HSS and degradation products from amine solutions mainly include ion exchange and electrodialysis (ED). Ion exchange purifies the solution by adsorbing HSS through resin. It is a mature technology with high removal efficiency, but the resin requires frequent chemical regeneration with strong acids and alkalis, generating large amounts of high-salinity wastewater and resulting in high treatment costs. Electrodialysis, driven by an electric field, utilizes the selectivity of the ion exchange membrane to direct the migration of HSS anions and metal cations, separating them from the amine solution. Electrodialysis offers advantages such as no need for chemical additives, continuous operation, and good removal of ionic pollutants. However, it suffers from problems such as membrane fouling caused by organic matter and colloidal substances in the amine solution, leading to decreased efficiency. Therefore, existing technologies generally suffer from problems such as high energy consumption, secondary pollution, discontinuous processes, or targeting only specific pollutants, lacking a comprehensive solution that can simultaneously, efficiently, and environmentally friendly deeply purify amine solutions. Summary of the Invention

[0005] Therefore, it is necessary to provide a decarbonized amine solution electrodialysis desalination purification and regeneration method that can efficiently, economically, and greenly remove HSS and degradation products, and realize online purification and regeneration of amine solution.

[0006] One embodiment of this application provides a method for desalination, purification, and regeneration of decarbonized amine solution via electrodialysis.

[0007] A method for desalination, purification, and regeneration of decarbonized amine solution via electrodialysis includes the following steps:

[0008] The decarbonized amine solution was pretreated to obtain a pretreated solution;

[0009] Furthermore, the pretreated solution is purified by electrodialysis.

[0010] In some embodiments, the pretreatment includes the following steps: filtering the decarbonized amine solution to remove solid particulate impurities from the solution.

[0011] In some embodiments, the pretreatment includes the following steps: filtering the decarbonized amine solution through a filter, wherein the filter element has a filter diameter of 5μm to 10μm.

[0012] In some embodiments, the temperature of the decarbonized amine solution is controlled at 40°C to 60°C during the pretreatment.

[0013] In some embodiments, the electrodialysis purification process employs an electrodialysis device, which includes an electrodialysis cell and an anode electrode, a first separator, a membrane contactor assembly, a second separator, and a cathode electrode distributed in the direction from anode to cathode within the electrodialysis cell.

[0014] In some embodiments, the membrane contactor assembly includes a housing, a membrane bundle located within the housing, and an encapsulation component. The membrane bundle includes a plurality of fiber membrane filaments, and the outer walls at both ends of adjacent fiber membrane filaments are fixedly connected to the housing via the encapsulation component and are sealed to the housing.

[0015] In some embodiments, the fibrous membrane fibers comprise hollow fiber anion exchange membranes.

[0016] In some embodiments, the materials used to prepare the fiber membrane include one or two of quaternized polysulfone (QAPS) and benzyl chloride.

[0017] In some embodiments, the number of fiber membrane filaments is 100 to 2000.

[0018] In some embodiments, the shell tube is made of one or both of polyvinylidene fluoride (PVDF) and polypropylene (PP).

[0019] In some embodiments, the materials used to prepare the encapsulation component include one or both of epoxy resin and polyurethane adhesive.

[0020] In some embodiments, the first and second isolation elements each independently comprise an ion exchange membrane or a porous plate.

[0021] In some embodiments, the anode electrode comprises titanium coated with ruthenium-iridium.

[0022] In some embodiments, the cathode electrode comprises stainless steel.

[0023] In some embodiments, the purified amine solution obtained from the electrodialysis purification process is transported to a storage tank for storage.

[0024] In some embodiments, the concentrated waste liquid obtained from the electrodialysis purification process is subjected to evaporation crystallization and / or biochemical treatment.

[0025] In some embodiments, the electrode wastewater generated by the electrodialysis purification process is either discharged externally or sent to a wastewater treatment system for treatment.

[0026] The aforementioned electrodialysis desalination and regeneration method for decarbonized amine solution combines the concepts of electrodialysis and membrane contactor modules to achieve decolorization and purification of the decarbonized amine solution and efficient amine recovery. Specifically, in this application's electrodialysis desalination and regeneration method for decarbonized amine solution, the selective electro-driven separation of electrodialysis is combined with the non-dispersive, high specific surface area mass transfer advantages of membrane contactor modules. The fiber membrane filaments in the membrane contactor module can be constructed using hollow fiber anion exchange membranes. The amine solution flows inside the tube of the membrane contactor module, while the receiving liquid flows outside the tube. Under the drive of a DC electric field, HSS anions in the amine solution selectively pass through the fiber membrane filaments of the membrane contactor module (such as hollow fiber anion exchange membranes) and are captured and neutralized in the receiving liquid (such as dilute alkali solution) on the other side. The electric field provides a strong driving force, which can simultaneously and deeply remove HSS and charged pigment molecules. This application is of great significance for improving the recycling efficiency of amine solutions and reducing operating costs. The above-mentioned electrodialysis desalination, purification, and regeneration method for decarbonized amine solution can efficiently, economically, and environmentally remove HSS and degradation products, realizing online purification and regeneration of amine solution. This technology is of great practical significance and urgency for ensuring the long-term stable operation of CCUS units and reducing operating costs.

[0027] In this application, the membrane contactor assembly structure provides a high specific surface area, resulting in high mass transfer efficiency, reduced unit processing energy consumption and equipment volume. Employing non-dispersive mass transfer, it fundamentally eliminates the foaming risks inherent in operations such as air stripping and bubbling, effectively addressing the bottlenecks of existing amine solution purification technologies. The electrodialysis desalination and regeneration method for decarbonized amine solutions in this application utilizes electrodialysis and membrane contactors for desalination and regeneration of the decarbonized amine solution. Utilizing an electric field to provide a powerful driving force, it can simultaneously and deeply remove HSS and charged pigment molecules, offering a more advanced and greener solution for the long-term, stable, and economical operation of CCUS devices. This method has significant scientific research value and broad industrial application prospects. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings. In the following description, the same reference numerals denote the same parts.

[0030] Figure 1 This is a schematic diagram of the process of electrodialysis desalination, purification and regeneration of decarbonized amine solution according to an embodiment of this application;

[0031] Figure 2 This is a schematic diagram of the electrodialysis apparatus in the electrodialysis desalination purification and regeneration method for decarbonized amine solution according to an embodiment of this application.

[0032] Explanation of reference numerals in the attached figures

[0033] 10. The electrodialysis apparatus; 100. Electrodialysis cell; 200. Anode electrode; 300. First separator; 400. Membrane contactor assembly; 500. Second separator; 600. Cathode electrode. Detailed Implementation

[0034] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0035] In the description of this application, 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", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0036] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," 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 or an electrical connection; 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 expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0037] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply 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 that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0039] In this document, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "with" or "without." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain."

[0040] In this document, unless otherwise stated, the reaction steps may be performed in the order described herein or not. For example, other steps may be included between reaction steps, and the order of reaction steps may be appropriately interchanged. This is something that those skilled in the art can determine based on conventional knowledge and experience. Preferably, the reaction methods described herein are performed sequentially.

[0041] In this application, when numerical intervals (i.e., numerical ranges) are mentioned, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0043] This application provides a method for desalination, purification, and regeneration of decarbonized amine solution via electrodialysis to address at least one of the following technical problems in conventional methods for removing HSS and degradation products from alkanolamine solutions: (1) In ion exchange methods, the resin requires frequent chemical regeneration with strong acids and alkalis, resulting in a large amount of high-salt wastewater and high treatment costs. (2) Electrodialysis methods suffer from problems such as membrane fouling and reduced efficiency caused by organic matter and colloidal substances in the amine solution. The method for desalination, purification, and regeneration of decarbonized amine solution via electrodialysis will be described below with reference to the accompanying drawings.

[0044] The electrodialysis desalination, purification, and regeneration method for decarbonized amine solution provided in one embodiment of this application is exemplary; please refer to [link to relevant documentation]. Figure 1 As shown, Figure 1 This is a schematic diagram of a decarbonized amine solution electrodialysis desalination purification and regeneration method provided in one embodiment of this application. The decarbonized amine solution electrodialysis desalination purification and regeneration method of this application can be used for simultaneous, efficient, and environmentally friendly deep purification of amine solutions.

[0045] To more clearly illustrate the structure of the electrodialysis desalination and purification regeneration method for decarbonized amine solution, the following description, in conjunction with the accompanying drawings, will introduce the method.

[0046] For example, please refer to Figure 1 As shown, a method for desalination, purification, and regeneration of decarbonized amine solution via electrodialysis includes the following steps:

[0047] S10. The decarbonized amine solution is pretreated to obtain a pretreated solution.

[0048] S20. The pretreatment solution is purified by electrodialysis.

[0049] In this application, the membrane contactor assembly structure provides a high specific surface area, resulting in high mass transfer efficiency, reduced unit processing energy consumption and equipment volume. Employing non-dispersive mass transfer, it fundamentally eliminates the foaming risks inherent in operations such as air stripping and bubbling, effectively addressing the bottlenecks of existing amine solution purification technologies. The electrodialysis desalination and regeneration method for decarbonized amine solutions in this application utilizes electrodialysis and membrane contactors for desalination and regeneration of the decarbonized amine solution. Utilizing an electric field to provide a powerful driving force, it can simultaneously and deeply remove HSS and charged pigment molecules, offering a more advanced and greener solution for the long-term, stable, and economical operation of CCUS devices. This method has significant scientific research value and broad industrial application prospects.

[0050] In this application, an electrodialysis device is used during purification. The electrodialysis device can achieve efficient and continuous desalination, ensuring the purity of the amine solution. Electrodialysis can selectively remove ionic impurities (such as chloride ions Cl) from the amine solution. - Sodium ions (Na) + Calcium ions (Ca) 2- Sulfate ions SO4 2- These impurities (such as foaming agents, corrosion, and degradation of amine solutions) are the main causes of foaming, equipment corrosion, and degradation in amine solutions. The entire process is a continuous physical separation process, unlike traditional ion exchange resins which require frequent shutdowns for regeneration. It enables continuous online purification, ensuring long-term stable operation of the amine solution system. This significantly reduces amine solution loss and operating costs. Electrodialysis uses an electric field to drive ion migration; amine molecules are electrically neutral and will not be removed by the membrane, resulting in extremely low amine loss (typically <1%). Compared to traditional "skimming" or "waste discharge" methods, which discharge large amounts of contaminated amine solution and cause direct loss of expensive amine solvent, electrodialysis has a significant advantage in this regard, directly saving on amine solution replenishment costs. Energy consumption is relatively low, primarily using electricity to drive ion migration. It does not require chemical regeneration agents (such as the acid and alkali regeneration required for ion exchange resins), avoiding the generation and treatment of hazardous chemical waste such as waste acid and alkali, making it more environmentally friendly.

[0051] In some embodiments, the pretreatment includes the following steps: filtering the decarbonized amine solution to remove solid particulate impurities, including rust and other impurities, from the solution to prevent them from clogging the membrane pores.

[0052] In some embodiments, the pretreatment includes the following step: filtering the decarbonized amine solution through a filter, wherein the filter element has a filter diameter of 5 μm to 10 μm. For example, the filter element diameter may be, but is not limited to, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm or any range between the two aforementioned.

[0053] In some embodiments, the filter described above may be selected from security filters.

[0054] In some embodiments, the temperature of the decarbonized amine solution is controlled to be between 40°C and 60°C during the pretreatment. For example, the temperature of the decarbonized amine solution during pretreatment may include, but is not limited to, 40°C, 42°C, 45°C, 48°C, 50°C, 52°C, 55°C, 58°C, 60°C, or any range between the foregoing.

[0055] In some of these implementations, please refer to Figure 2 As shown, Figure 2 This is a schematic diagram of an electrodialysis apparatus in an electrodialysis desalination and purification regeneration method for decarbonized amine solution provided in one embodiment of this application. The electrodialysis purification process utilizes an electrodialysis apparatus. The electrodialysis apparatus includes an electrodialysis cell and, within the electrodialysis cell, an anode electrode, a first separator, a membrane contactor assembly, a second separator, and a cathode electrode, distributed from the anode to the cathode direction.

[0056] In some embodiments, the voltage between the anode electrode and the cathode electrode is controlled to be 20V~50V.

[0057] In some embodiments, the membrane contactor assembly includes a shell tube, a membrane bundle located within the shell tube, and an encapsulation component. The membrane bundle includes a plurality of fiber membrane filaments. The outer walls at both ends of adjacent fiber membrane filaments are fixedly connected to the shell tube by the encapsulation component and are sealed to the shell tube. That is, the two ends of the fiber membrane filaments are sealed to the shell tube by the encapsulation component, and the gaps between adjacent fiber membrane filaments are sealed at both ends of the shell tube. However, there is no encapsulation component at the middle of the fiber membrane filaments, and the fiber membrane filaments are in a state of being open at both ends. This allows the pretreatment solution to enter the fiber membrane filaments through the opening at one end of the shell tube, move laterally inside the shell tube to the outside of the fiber membrane filaments, and flow out through the opening at the other end of the shell tube.

[0058] In some embodiments, the fibrous membrane fibers comprise hollow fiber anion exchange membranes (AEMs).

[0059] In some embodiments, the materials used to prepare the fiber membrane include one or two of quaternized polysulfone (QAPS) and benzyl chloride.

[0060] In some embodiments, the number of fiber membrane filaments is 100 to 2000. For example, the number of fiber membrane filaments includes, but is not limited to: 100, 500, 800, 1000, 1300, 1500, 1800, 2000 or any range between the two.

[0061] In some embodiments, the shell tube is made of one or both of polyvinylidene fluoride (PVDF) and polypropylene (PP).

[0062] In some embodiments, the materials used to prepare the encapsulation component include one or both of epoxy resin and polyurethane adhesive.

[0063] The fabrication of the membrane contactor assembly includes the following steps:

[0064] In some embodiments, the membrane bundle is prepared by arranging hundreds to thousands of fiber membrane filaments, such as hollow fiber anion exchange membranes (AEMs), in parallel to form a neat membrane bundle. The ends of the membrane bundle are then neatly cut with a blade to ensure that all fiber ends are open and unblocked.

[0065] The module is encapsulated by carefully inserting the prepared membrane bundle into the shell tube of PVDF material.

[0066] For tube-side end sealing, the shell-and-tube module containing the membrane bundle is vertically fixed, and the encapsulation material, such as epoxy resin, is injected into one end (lower end). This ensures that the epoxy resin fully penetrates the gaps between the fiber membrane filaments, bonding the fiber membrane filaments together and attaching them to the shell-and-tube. After curing, this end of the tube side (inner side of the fiber) is sealed, while the shell side (outer side of the fiber) remains open.

[0067] Shell-side end sealing: The shell-and-tube module containing the membrane bundle is inverted, and the same operation is performed on the other end. At this time, the hollow fiber interiors (tube side) at both ends of the module are sealed with epoxy resin, while the channels between the fiber membrane filaments and between the fiber membrane filaments and the outer shell (shell side) are open.

[0068] End cutting: After the epoxy resin has fully cured, use a precision cutting tool to cut off a thin layer of the end caps to re-expose the tube-side inner hole of each fiber membrane filament, while ensuring that the shell-side channel is still sealed by the resin.

[0069] Installation ports: Inlet and outlet ports are opened on the shell side of the shell tube.

[0070] In this application, the membrane bundle is formed by multiple extremely fine hollow fiber anion exchange membranes (AEMs) arranged in parallel. The membrane bundle in this application serves as a mass transfer interface: like ordinary hollow fibers, it provides a large contact area. As an ion selector: like an electrodialysis membrane, it allows only anions to pass through. The membrane bundle's working process is as follows: the contaminating amine solution flows in the tube side inside the fibers of the membrane bundle, while the receiving solution (such as dilute NaOH) flows in the shell side outside the fibers. Driven by an electric field, the anionic contaminants (Cl-) in the amine solution... - HCOO - The amine (e.g., amine) passes through the fiber membrane wall and enters the receiving liquid in the shell side, where it is removed. The two ends of the membrane bundle are encapsulated and cured with epoxy resin to form a "tube sheet." This serves two purposes: firstly, it provides physical support, fixing thousands of fibers in place; secondly, it provides a fluid seal, ensuring complete fluid isolation between the tube side (inner side of the fiber) and the shell side (outer side of the fiber), preventing short circuits. After being cut at both ends, the tube side of the fiber is opened, allowing the amine solution to flow in and out of the fiber. At both ends of the membrane bundle, an anode (e.g., a DSA electrode) and a cathode (e.g., stainless steel) are placed, forming independent electrode chambers. When a DC power supply is applied, a DC electric field is established between the two electrodes, penetrating the entire membrane bundle, providing the core driving force for the directional migration of anions. Between the electrode chambers and the membrane bundle, there is a cation exchange membrane (CEM) or a standard anion exchange membrane (AEM). This separates the electrode chambers from the main membrane stack, preventing direct contact between the amine solution and the electrodes and avoiding oxidation side reactions, while also eliminating interference from gases (O2, H2) generated during electrolysis.

[0071] In some embodiments, the first and second isolation elements each independently comprise an ion exchange membrane or a porous plate.

[0072] In some embodiments, the anode electrode includes a titanium-coated ruthenium-iridium (DSA electrode). The titanium-coated ruthenium-iridium, also known as a chlorine-evolving DSA electrode, is an electrode on which an active catalytic layer composed of noble metal oxides such as ruthenium and iridium is coated on a pure titanium substrate by means of thermal decomposition or other methods. Its core features are excellent electrocatalytic activity, high stability and long life. The metallic titanium substrate of the DSA electrode hardly dissolves under electrolysis conditions, and the catalytic layer on the surface is also very stable, so its physical size and shape remain unchanged during long-term use. The ruthenium and iridium coating in the DSA electrode is not simply metallic ruthenium and iridium, but their oxides. The DSA electrode used in this application can achieve the following effects: (1) Electrocatalytic effect: significantly reduces the overpotential of the electrode reaction. Ruthenium oxide has extremely high catalytic activity, making the reaction easier to proceed, thereby greatly reducing the power consumption. (2) Conductivity: TiO2 on the surface of the titanium substrate is insulating, but after being coated with metal oxides such as RuO2, they have good conductivity, ensuring that the current passes smoothly. (3) Stability: This coating is firmly bonded to the titanium substrate and can withstand high current density and highly corrosive chlorine and acidic environments for a long time, ensuring the long life of the electrode.

[0073] In some embodiments, the cathode electrode comprises stainless steel. In an electrochemical cell paired with a DSA anode (such as titanium coated with ruthenium-iridium), the cathode is the electrode where the reduction reaction (gaining electrons) occurs. The choice of cathode material is crucial to efficiency, cost, and stability. Based on this, this application selects stainless steel as the cathode electrode material. Advantages of stainless steel as a cathode electrode: (1) Low cost, which is the most prominent advantage of stainless steel. Compared with precious metal cathodes such as platinum and platinum-plated titanium, stainless steel is very inexpensive, which can significantly reduce equipment investment costs. (2) Good corrosion resistance. In various cathode environments (especially alkaline environments), a passivation film will form on the surface of stainless steel, which has sufficient corrosion resistance and can ensure a long service life. (3) Sufficient conductivity. Stainless steel has good electronic conductivity, which can effectively transfer current and ensure that the electrochemical reaction proceeds efficiently. (4) High mechanical strength. Stainless steel has strength, hardness, and toughness, and is easy to process into various shapes (such as plates and meshes). As an electrode structure, it is stable and not easily deformed or damaged. (5) Hydrogen evolution catalytic activity. Stainless steel has a certain catalytic activity for the hydrogen evolution reaction.

[0074] In some embodiments, the purified amine solution obtained from the electrodialysis purification process is transported to a storage tank for storage.

[0075] In some embodiments, the concentrated waste liquid obtained from the electrodialysis purification process is subjected to evaporation crystallization and / or biochemical treatment.

[0076] In some embodiments, the electrode wastewater generated by the electrodialysis purification process is either discharged externally or sent to a wastewater treatment system for treatment.

[0077] In some embodiments, the receiving liquid includes a dilute NaOH solution or deionized water with a mass concentration of 1wt% to 5wt%.

[0078] In some embodiments, the flow direction in this application is as follows:

[0079] Amine solution flow (tube side): The pretreated solution enters from the tube side inlet at one end of the membrane contactor assembly, flows through the inner cavity of the fiber membrane filament, and then flows out at one end.

[0080] Receiver flow (shell side): The receiver liquid, such as dilute NaOH solution, enters from the shell side inlet and flows on the outside of the membrane contactor assembly, in a countercurrent or cross-flow manner with the amine liquid.

[0081] The purified amine solution flows out of the tube outlet. Most of the HSS anions and charged pigment molecules in the purified amine solution have been removed, the conductivity has decreased, and the liquid is returned to the storage tank.

[0082] Concentrated waste liquid: flowing out of the shell-side outlet, the concentrated waste liquid contains anions (such as formate, acetate, Cl-) that migrated from the amine solution. - These substances, along with the salts formed by their neutralization with NaOH (such as sodium formate and sodium acetate), dissolve in the solution. This stream is high-salinity wastewater and is collected for further treatment (such as evaporation crystallization or biochemical treatment).

[0083] Electrode wastewater: Acidic wastewater circulating in the electrode chamber, which is discharged periodically.

[0084] The aforementioned electrodialysis desalination and regeneration method for decarbonized amine solution combines the concepts of electrodialysis and membrane contactor modules to achieve decolorization and purification of the decarbonized amine solution and efficient amine recovery. Specifically, in this application's electrodialysis desalination and regeneration method for decarbonized amine solution, the selective electro-driven separation of electrodialysis is combined with the non-dispersive, high specific surface area mass transfer advantages of membrane contactor modules. The fiber membrane filaments in the membrane contactor module can be constructed using hollow fiber anion exchange membranes. The amine solution flows inside the tube of the membrane contactor module, while the receiving liquid flows outside the tube. Under the drive of a DC electric field, HSS anions in the amine solution selectively pass through the fiber membrane filaments of the membrane contactor module (such as hollow fiber anion exchange membranes) and are captured and neutralized in the receiving liquid (such as dilute alkali solution) on the other side. The electric field provides a strong driving force, which can simultaneously and deeply remove HSS and charged pigment molecules. This application is of great significance for improving the recycling efficiency of amine solutions and reducing operating costs. The above-mentioned electrodialysis desalination, purification, and regeneration method for decarbonized amine solution can efficiently, economically, and environmentally remove HSS and degradation products, realizing online purification and regeneration of amine solution. This technology is of great practical significance and urgency for ensuring the long-term stable operation of CCUS units and reducing operating costs.

[0085] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0086] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0087] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for electrodialysis desalination, purification, and regeneration of decarbonized amine solution, characterized in that, Includes the following steps: The decarbonized amine solution was pretreated to obtain a pretreated solution; Furthermore, the pretreated solution is purified by electrodialysis.

2. The method for electrodialysis desalination, purification, and regeneration of decarbonized amine solution according to claim 1, characterized in that, The pretreatment includes the following steps: filtering the decarbonized amine solution to remove solid particulate impurities from the solution.

3. The method for electrodialysis desalination, purification, and regeneration of decarbonized amine solution according to claim 2, characterized in that, At least one of the following conditions must be met: (1) The pretreatment includes the following steps: filtering the decarbonized amine solution through a filter, wherein the filter element has a filter diameter of 5μm~10μm; (2) The temperature of the decarbonized amine solution is controlled at 40℃~60℃ during the pretreatment.

4. The method for electrodialysis desalination, purification, and regeneration of decarbonized amine solution according to claim 1, characterized in that, The electrodialysis purification process employs an electrodialysis device, which includes an electrodialysis tank and an anode electrode, a first separator, a membrane contactor assembly, a second separator, and a cathode electrode distributed in the direction from anode to cathode within the electrodialysis tank.

5. The method for electrodialysis desalination, purification, and regeneration of decarbonized amine solution according to claim 4, characterized in that, The membrane contactor assembly includes a shell tube, a membrane bundle located inside the shell tube, and an encapsulation component. The membrane bundle includes a plurality of fiber membrane filaments that extend along the length of the shell tube. The outer walls at both ends of adjacent fiber membrane filaments are fixedly connected to the shell tube by the encapsulation component and are sealed to the shell tube.

6. The method for electrodialysis desalination, purification, and regeneration of decarbonized amine solution according to claim 5, characterized in that, The fiber membrane filaments include hollow fiber anion exchange membranes; Optionally, the material used to prepare the fiber membrane includes one or two of quaternized polysulfone and benzyl chloride. And / or, the number of the fiber membrane filaments is 100 to 2000.

7. The method for electrodialysis desalination, purification, and regeneration of decarbonized amine solution according to claim 5, characterized in that, The electrodialysis apparatus satisfies at least one of the following conditions: (1) The materials used to prepare the shell tube include one or both of polyvinylidene fluoride and polypropylene; (2) The materials used to prepare the encapsulation component include one or both of epoxy resin and polyurethane adhesive.

8. The method for electrodialysis desalination, purification, and regeneration of decarbonized amine solution according to any one of claims 4 to 7, characterized in that, The first and second isolation components each independently include an ion exchange membrane or a porous plate.

9. The method for electrodialysis desalination, purification, and regeneration of decarbonized amine solution according to any one of claims 4 to 7, characterized in that, The electrodialysis apparatus satisfies at least one of the following conditions: (1) The anode electrode comprises titanium coated with ruthenium-iridium; (2) The cathode electrode is made of stainless steel.

10. The method for electrodialysis desalination, purification, and regeneration of decarbonized amine solution according to any one of claims 1 to 7, characterized in that, It also includes the following steps: (1) The purified amine solution obtained by the electrodialysis purification process is transported to a storage tank for storage; (2) The concentrated waste liquid obtained from the electrodialysis purification process is subjected to evaporation crystallization and / or biochemical treatment; (3) The electrode wastewater generated by the electrodialysis purification process is discharged externally or sent to the sewage treatment system for treatment.

Images