Purification method and purification system for decarburized amine solution
By employing a synergistic treatment method combining membrane filtration, membrane extraction, and membrane stripping, the problems of long purification cycles and high energy consumption in the purification of decarbonized amine solutions have been solved. This method achieves efficient removal of impurities and efficient recovery of amine solutions, making it suitable for the recycling of industrial decarbonized amine solutions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-02
- Publication Date
- 2026-05-19
AI Technical Summary
Existing methods for purifying decarbonized amine solutions suffer from problems such as long purification cycles, high energy consumption, equipment corrosion, and impurity accumulation, especially the difficulty in effectively removing impurities such as heat-stable salts.
A synergistic treatment method combining membrane filtration, membrane extraction, and membrane stripping is employed. Solid impurities are removed through a filter membrane with a specific pore size, heat-stable salts are removed using alkaline solution or water as the extraction liquid, and volatile degradation products are removed using inert gas as the stripping gas, thereby achieving efficient recovery of amine solution.
It shortens the purification cycle, reduces energy consumption costs, improves purification efficiency and amine recovery rate, and meets the needs of industrial decarbonized amine liquid recycling.
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Figure CN122057355A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of carbon dioxide capture technology, specifically to a purification method and system for decarbonized amine solution. Background Technology
[0002] In industrial production and energy utilization processes, natural gas extraction, thermal power generation, and coal chemical industries emit large amounts of mixed gases containing carbon dioxide (CO2). With low-carbon development becoming an industry consensus, carbon capture, utilization, and storage (CCUS) technology has become a key approach to reducing industrial carbon emissions.
[0003] Current CO2 capture primarily relies on amine absorption, with the core functional solution being decarbonized amine solution. Decarbonized amine solution is an aqueous solution prepared from amine compounds (such as ethanolamine MEA, N-methyldiethanolamine MDEA, etc.) and water in a specific ratio. It achieves CO2 separation and recovery through an "absorption-desorption" cycle. However, the desorption process of decarbonized amine solution requires high temperatures, which generates a series of heat-stable salts (HSS) such as formate, acetate, sulfate, and oxalate, as well as other impurities. The anions in these heat-stable salts can form ionic bonds with amine molecules, preventing their decomposition through heating in the regeneration tower, thus leading to their continuous accumulation in the system. Therefore, these impurities not only reduce the absorption capacity and reaction kinetics of the decarbonized amine solution, resulting in increased system energy consumption, but are also the main causes of equipment corrosion, amine solution foaming, and severe solution discoloration (turning dark brown or bluish-black).
[0004] Currently, the main methods for removing impurities such as HSS from decarbonized amine solutions are ion exchange and vacuum distillation. However, ion exchange resins have a limited lifespan, requiring frequent replacement and resulting in long purification cycles; vacuum distillation consumes a large amount of heat energy to maintain a negative pressure environment, leading to high energy costs. Therefore, there is an urgent need for a purification method for decarbonized amine solutions that combines short purification cycles, low energy costs, and stable and efficient removal of impurities such as HSS. Summary of the Invention
[0005] Based on this, this application provides a purification method and system for decarbonized amine liquid. The purification method for decarbonized amine liquid provided by this application has a short purification cycle, low energy consumption, and can efficiently remove impurities, thereby achieving efficient recovery of amine liquid.
[0006] A first aspect of this application provides a method for purifying a decarbonized amine solution, comprising the following steps:
[0007] The decarbonized amine solution was subjected to membrane filtration, and the amine filtrate was collected; wherein the pore size of the membrane used in the membrane filtration process was 0.01μm~0.1μm;
[0008] The amine solution filtrate is subjected to membrane extraction to collect the purified amine solution; wherein the extractant used in the membrane extraction process includes an alkaline solution or water;
[0009] The amine solution is subjected to membrane stripping treatment using stripping gas to collect the amine-rich solution; wherein the stripping gas includes one or more of inert gas, carbon dioxide, water vapor and air.
[0010] In some embodiments, the decarbonized amine solution is an aqueous solution of an amine compound.
[0011] In some embodiments, the impurities in the decarbonized amine solution include one or more of particulate matter, heat-stable salts, and volatile degradation products.
[0012] In some embodiments, the decarbonized amine solution includes one or more of ethanolamine solution and N-methyldiethanolamine solution.
[0013] In some embodiments, the step of membrane filtration of the decarbonized amine solution includes:
[0014] Take the decarbonized amine solution at a temperature of 40℃~60℃, and let the decarbonized amine solution flow through a filter membrane with a pore size of 0.01μm~0.1μm under a pressure of 0.01MPa~0.5MPa to remove particulate matter, and collect the amine solution filtrate and retentate.
[0015] In some embodiments, the step of performing membrane extraction on the amine filtrate includes:
[0016] The amine filtrate is subjected to membrane extraction using a first hollow fiber membrane, wherein the amine filtrate flows through the inside of the first hollow fiber membrane and the extract flows through the outside of the first hollow fiber membrane to remove the heat-stable salt, and the purified amine filtrate and waste extract are collected.
[0017] In some embodiments, the extract comprises an aqueous solution of sodium hydroxide or water with a mass fraction of 1% to 5%.
[0018] In some embodiments, the first hollow fiber membrane is hydrophobic.
[0019] In some embodiments, the flow rate of the amine filtrate is 2 mL / min to 5 mL / min.
[0020] In some embodiments, the flow rate of the extract is 2 mL / min to 5 mL / min.
[0021] In some embodiments, the purification method further includes neutralizing or evaporating the waste extract into crystals.
[0022] In some embodiments, the step of performing membrane stripping treatment on the amine purification liquid using stripping gas includes:
[0023] The amine purification liquid is subjected to membrane stripping treatment using a second hollow fiber membrane, wherein the amine purification liquid flows through the interior of the second hollow fiber membrane, and the stripping gas flows through the exterior of the second hollow fiber membrane to remove the volatile degradation products and collect the amine-rich liquid and waste gas.
[0024] In some embodiments, the second hollow fiber membrane is hydrophobic.
[0025] In some embodiments, the flow rate of the amine purification solution is 0.3 mL / min to 6 mL / min.
[0026] In some embodiments, the flow rate of the gas extraction gas is 0.5 mL / min to 10 mL / min.
[0027] In some embodiments, the purification method further includes: conveying the waste gas to a waste gas scrubbing tower or to an incinerator for post-treatment.
[0028] In some embodiments, prior to the step of membrane filtration of the decarbonized amine solution, the method further includes pretreatment of the decarbonized amine solution to remove suspended solids.
[0029] A second aspect of this application provides a purification system for decarbonized amine solution, used in the purification method for decarbonized amine solution described in the first aspect of this application, the purification system comprising:
[0030] A membrane filtration assembly for performing membrane filtration treatment on the decarbonized amine solution;
[0031] A membrane extraction assembly for performing membrane extraction treatment on the amine filtrate;
[0032] A membrane stripping unit is used to perform membrane stripping treatment on the amine purification solution.
[0033] The purification method for decarbonized amine solution provided in this application has at least the following advantages:
[0034] The purification method provided in this application achieves impurity removal and efficient amine recovery through the synergistic treatment of membrane filtration, membrane extraction, and membrane stripping. Specifically, the filter membrane with a specific pore size can trap solid impurities such as micron-sized particles, which avoids membrane pore blockage in subsequent membrane extraction and membrane stripping units, ensuring continuous and stable operation of the entire purification process; and it does not require frequent replacement of resin consumables like ion exchange, thus shortening the purification cycle. Membrane extraction uses alkaline solution or water as the extractant, removing residual heat-stable salts (such as HSS) from the amine solution through non-dispersive contact. The extractant and amine filtrate are not directly mixed, reducing reagent consumption and subsequent separation difficulties. Membrane stripping uses inert gas, carbon dioxide, water vapor, or air as the stripping gas, increasing the amine concentration to obtain an amine-rich solution under mild conditions. Therefore, it does not require the large amount of heat energy consumed to maintain a negative pressure environment as in vacuum distillation, significantly reducing energy costs. Therefore, the purification method provided in this application achieves the stepwise removal of different types of impurities through three-stage membrane treatment, while maximizing the retention of effective components in the amine solution. It balances purification efficiency, operational economy, and amine solution recovery rate, and is suitable for the need for recycling industrial decarbonized amine solution. Attached Figure Description
[0035] Figure 1 A process flow diagram of the purification method for the decarbonized amine solution provided in this application. Detailed Implementation
[0036] The purification method and system for decarbonized amine solution of this application are further described in detail below with reference to specific embodiments. This application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.
[0037] In this application, 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. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0038] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.
[0039] 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 in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise stated or in case of conflict, the terms or phrases used herein have the following meanings:
[0040] In this application, the terms "multiple", "various", "multiple times", "multi-dimensional", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more or more.
[0041] In this application, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth," etc., serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.
[0042] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.
[0043] In this application, the terms "combinations thereof", "any combination thereof", and "any combination thereof" include all suitable combinations of any two or more of the listed items.
[0044] In this application, the term "suitable" as used in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.
[0045] In this application, terms such as "preferred," "better," "more suitable," and "ideal" are used only to describe implementation methods or embodiments with better effects, and should be understood not to constitute a limitation on the scope of protection of this application.
[0046] In this application, terms such as "further," "even further," and "particularly" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this application.
[0047] In this application, the terms "optionally," "optionally," and "optional" refer to options that are optional, meaning they can be selected from either "with" or "without." If multiple "optional" options appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" option is independent.
[0048] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In this document, this is equivalent to directly listing every integer. For example, if t is an integer selected from 1 to 10, it means that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.
[0049] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.
[0050] In this application, percentage content refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures, unless otherwise specified.
[0051] In this application, percentage concentrations, unless otherwise specified, refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.
[0052] Currently, the main methods for removing impurities such as HSS from decarbonized amine solutions are ion exchange and vacuum distillation. Ion exchange resins have a limited lifespan, requiring frequent resin replacement or chemical regeneration with strong acids and alkalis, resulting in long purification cycles and high wastewater treatment costs. Vacuum distillation consumes significant amounts of heat energy to maintain a negative pressure environment, leading to high energy costs. Other purification methods for decarbonized amine solutions include electrodialysis, but this method has weak retention capacity for HSS and other impurities, requiring periodic shutdowns for cleaning and maintenance, affecting the continuity of purification. Furthermore, the initial investment in this equipment is high, making it unsuitable for large-scale purification scenarios with high impurity concentrations in amine solutions.
[0053] A first aspect of this application provides a method for purifying a decarbonized amine solution, comprising the following steps:
[0054] S11: The decarbonized amine solution is filtered through a membrane and the amine filtrate is collected.
[0055] S12: Perform membrane extraction on the amine filtrate to collect the purified amine solution.
[0056] S13: The amine solution is subjected to membrane stripping treatment using stripping gas to collect the amine-rich solution.
[0057] In some of these examples, in step S11, the membrane used in the membrane filtration process has a pore size of 0.01 μm to 0.1 μm.
[0058] In some of these examples, in step S12, the extractant used in the membrane extraction process includes an alkaline solution or water.
[0059] In some of these examples, in step S13, the gas extraction gas includes one or more of an inert gas, carbon dioxide, water vapor, and air.
[0060] The purification method provided in this application achieves impurity removal and efficient amine recovery through the synergistic treatment of membrane filtration, membrane extraction, and membrane stripping. Specifically, the filter membrane with a specific pore size can trap solid impurities such as micron-sized particles, avoiding membrane pore blockage in subsequent membrane extraction and membrane stripping units, thus ensuring the continuous and stable operation of the entire purification process. Furthermore, unlike ion exchange methods, it eliminates the need for frequent resin replacement or regeneration with strong acids or alkalis, shortening the purification cycle and reducing chemical consumption and wastewater treatment costs. Membrane extraction uses alkaline solution or water as the extractant, removing residual heat-stable salts (such as HSS) from the amine solution through non-dispersive contact. The extractant and amine filtrate are not directly mixed, reducing reagent loss and subsequent separation difficulties. Membrane stripping uses inert gas, carbon dioxide, water vapor, or air as the stripping gas, increasing the amine concentration to obtain an amine-rich solution under mild conditions. Unlike vacuum distillation, it does not require the large amount of heat energy to maintain a negative pressure environment, thus significantly reducing energy costs. The purification method provided in this application achieves the tiered removal of different types of impurities through three-stage membrane treatment, while maximizing the retention of the effective components of the amine solution. It balances purification efficiency, operational economy, and amine solution recovery rate, and is suitable for the recycling of industrial decarbonized amine solution.
[0061] In some of these examples, the decarbonized amine solution is an aqueous solution of an amine compound.
[0062] In some of these examples, the impurities in the decarbonized amine solution include one or more of particulate matter, thermally stable salts, and volatile degradation products.
[0063] For example, the anion of the thermally stable salt HSS can be exemplified as formate HCOO. - Acetate CH3COO - Chloride ions Cl - or sulfate SO4 2- .
[0064] Volatile degradation products may include CO2, H2S, NH3, or low-molecular-weight volatile organic acids.
[0065] In some of these examples, the decarbonized amine solution includes one or more of ethanolamine solution and N-methyldiethanolamine solution.
[0066] In some examples, prior to the step of membrane filtration of the decarbonized amine solution, the method further includes: S10: pre-treating the decarbonized amine solution to remove suspended solids from the decarbonized amine solution.
[0067] For example, the solid suspended matter in the decarbonized amine solution includes one or more of the following: corrosion products FeS, carbon powder, catalyst powder, and macromolecular colloids.
[0068] In some of these examples, step S11, which involves membrane filtration of the decarbonized amine solution, includes:
[0069] Take the decarbonized amine solution at a temperature of 40℃~60℃, and let the decarbonized amine solution flow through a filter membrane with a pore size of 0.01μm~0.1μm under a pressure of 0.01MPa~0.5MPa to remove particulate matter, and collect the amine solution filtrate and retentate.
[0070] For example, a filter membrane with a pore size of 0.01 μm to 0.1 μm is a microfiltration membrane or an ultrafiltration membrane. When the decarbonized amine solution flows through the filter membrane, the small molecule dissolved in the amine molecules can pass through the filter membrane, while solid particulate matter is retained, thus obtaining an amine solution filtrate with particulate matter removed.
[0071] Understandably, see Figure 1 The decarbonized amine solution at a temperature of 40℃~60℃ does not require special heating and can be obtained by diverting the regenerated CO2-lean decarbonized amine solution. The pressure in the membrane filtration treatment step includes, but is not limited to, 0.01MPa, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa or 0.5MPa, or any two of the above points as endpoints.
[0072] In addition, the filter membrane can be cleaned to remove trapped particles.
[0073] In some examples, step S11, which involves membrane extraction of the amine filtrate, includes:
[0074] The amine filtrate is subjected to membrane extraction using a first hollow fiber membrane, wherein the amine filtrate flows through the inside of the first hollow fiber membrane and the extract flows through the outside of the first hollow fiber membrane to remove the heat-stable salt, and the purified amine filtrate and waste extract are collected.
[0075] In some of these examples, the flow rate of the amine filtrate is 2 mL / min to 5 mL / min.
[0076] In some of these examples, the flow rate of the extract was 2 mL / min to 5 mL / min.
[0077] In some examples, the extract comprises an aqueous solution of sodium hydroxide or water with a mass fraction of 1% to 5%. For example, the mass fraction of sodium hydroxide in the aqueous solution includes, but is not limited to, 1%, 2%, 3%, 4%, or 5%, or a range formed by any two of the above points as endpoints.
[0078] In some of these examples, the first hollow fiber membrane is hydrophobic.
[0079] For example, the device including the first hollow fiber membrane can be a hollow fiber membrane contactor, in which the extract flows through the shell side of the hollow fiber membrane contactor and the amine filtrate flows through the tube side of the hollow fiber membrane contactor, so that the two achieve non-dispersive contact at the membrane wall of the hollow fiber membrane. The hollow fiber membrane contactor has a large specific surface area, which can save a lot of space and is beneficial to improving mass transfer efficiency.
[0080] In this process, HSS anions (in the form of A) - (This indicates that) it will react with H inside the amine filtrate. + The HA molecules combine to form neutral molecules. The HA molecules dissolve in the amine filtrate and diffuse through the hydrophobic first hollow fiber membrane to enter the extract side. Preferably, the extract comprises a 1%–5% (w / w) aqueous solution of sodium hydroxide. At this point, HA can be neutralized and re-dissociate into A. - and Na + The reaction HA + NaOH → NaA + H2O occurs, driving the flow of HA and causing A to flow. - It is present in the extract.
[0081] In some examples, the purification method further includes neutralizing or evaporating the waste extract. Understandably, systems for neutralization or evaporation crystallization include, but are not limited to, wastewater treatment systems.
[0082] In some examples, step S13, which involves performing membrane stripping treatment on the purified amine solution using stripping gas, includes:
[0083] The amine purification liquid is subjected to membrane stripping treatment using a second hollow fiber membrane, wherein the amine purification liquid flows through the interior of the second hollow fiber membrane, and the stripping gas flows through the exterior of the second hollow fiber membrane to remove the volatile degradation products and collect the amine-rich liquid and waste gas.
[0084] In some of these examples, the second hollow fiber membrane is hydrophobic.
[0085] In some of these examples, the flow rate of the amine purification solution is 0.3 mL / min to 6 mL / min.
[0086] In some of these examples, the flow rate of the stripping gas is 0.5 mL / min to 10 mL / min.
[0087] In some of these examples, the inert gas includes, but is not limited to, nitrogen.
[0088] Understandably, the first hollow fiber membrane and the second hollow fiber membrane can be the same.
[0089] For example, the device including the second hollow fiber membrane can be a hollow fiber membrane contactor, in which case the stripping gas flows through the shell side of the hollow fiber membrane contactor, and the amine purification liquid flows through the tube side of the hollow fiber membrane contactor. In this step, volatile degradation products in the amine purification liquid diffuse to the gas-liquid interface within the pores of the second hollow fiber membrane, and then evaporate into the stripping gas. Furthermore, the flow of the stripping gas maintains a low partial pressure at the interface, thereby creating a continuous mass transfer driving force.
[0090] Furthermore, this application found that the color of the amine-rich liquid after membrane stripping is reduced due to the decrease in impurities; at this time, the amine-rich liquid can be used for CO2 absorption and capture by amine method.
[0091] In some examples, the purification method further includes conveying the waste gas to a waste gas scrubbing tower or to an incinerator for post-treatment.
[0092] A second aspect of this application provides a purification system for decarbonized amine solution, used in the purification method for decarbonized amine solution described in the first aspect of this application, the purification system comprising:
[0093] A membrane filtration assembly for performing membrane filtration treatment on the decarbonized amine solution;
[0094] A membrane extraction assembly for performing membrane extraction treatment on the amine filtrate;
[0095] A membrane stripping unit is used to perform membrane stripping treatment on the amine purification solution.
[0096] Understandably, the first hollow fiber membrane used in the membrane extraction module and the second hollow fiber membrane used in the membrane stripping module can be the same, so the membrane extraction module and the membrane stripping module can also be the same.
[0097] The purification system for decarbonized amine liquid provided in this application adopts a modular design, which facilitates the scaling up or down of each component according to the processing capacity. The entire process can be easily automated and continuous through a programmable logic controller (PLC) and a distributed control system (DCS), reducing manual operation and intervention. Furthermore, the aforementioned system works synergistically with the purification method provided in this application, solving problems such as high energy consumption and incomplete purification in traditional decarbonized amine liquid purification processes. Therefore, the purification system or method for decarbonized amine liquid provided in this application is of great significance for ensuring long-term, low-cost, and stable operation of CCUS.
[0098] The following detailed embodiments illustrate this application in more detail. It should also be understood that the following embodiments are for further explanation only and should not be construed as limiting the scope of protection of this application. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of this application fall within the scope of protection of this application. The specific process parameters, etc., in the following embodiments are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the range based on the description herein, and are not necessarily limited to the specific values in the embodiments below.
[0099] Example 1
[0100] (1) The decarbonized amine solution (ethanolamine solution) used for CO2 absorption and capture by amine method is used as the initial solution. It is obtained by splitting the decarbonized amine solution with a lean CO2 at the outlet of the regeneration tower. The decarbonized amine solution with a temperature of 50°C at the outlet is flowed through a filter membrane with a pore size of 0.01μm~0.1μm under a pressure of 0.1MPa to remove particulate matter and collect the amine solution filtrate and retentate.
[0101] (2) A hydrophobic hollow fiber membrane contactor (including hollow cellulose acetate membrane) is used to perform membrane extraction treatment on the amine filtrate. The amine filtrate flows through the tube side of the hollow fiber membrane contactor at a flow rate of 4 mL / min, and the extract (2% sodium hydroxide aqueous solution by mass) flows through the shell side of the hydrophobic hollow fiber membrane contactor at a flow rate of 4 mL / min to remove heat-stable salts and collect the purified amine filtrate and waste extract.
[0102] (3) A hydrophobic hollow fiber membrane contactor (including hollow cellulose acetate membrane) is used to perform membrane stripping treatment on the amine purification liquid. The amine purification liquid flows through the tube side of the hydrophobic hollow fiber membrane contactor at a flow rate of 0.3 m / min, and the stripping gas nitrogen flows through the shell side at a flow rate of 0.5 m / min to remove volatile degradation products and collect the amine-rich liquid and waste gas.
[0103] The initial solution contained 3% heat-stable salt (calculated as anion), 25% ethanolamine, and 1% solid particulate matter.
[0104] The purified amine-rich solution contained 0.8% heat-stable salt (calculated as anion), 20% ethanolamine, and 0.3% solid particulate matter.
[0105] Example 2
[0106] Example 2 is basically the same as Example 1, the main difference being that the extraction solution used in step (2) of Example 2 is a sodium hydroxide aqueous solution with a mass fraction of 4%.
[0107] The test results showed that the mass concentration of heat-stable salts in the purified amine-rich solution was 0.7%, the mass concentration of ethanolamine was 22%, and the mass concentration of solid particles was 0.3%.
[0108] Example 3
[0109] Example 3 is basically the same as Example 1, the main difference being that the gas stripping gas in step (3) of Example 3 is carbon dioxide.
[0110] Testing revealed that the purified amine-rich solution contained heat-stable salts (primarily anionic chloride ions, Cl-). - The mass concentration of (calculated) is 0.8%, the mass concentration of ethanolamine is 22%, and the mass concentration of solid particulate matter is 0.3%.
[0111] Comparative Example 1
[0112] Comparative Example 1 is basically the same as Example 1, except that Comparative Example 1 does not include step (2); step (3) directly performs membrane stripping treatment on the amine filtrate.
[0113] Testing revealed that the purified amine-rich solution contained heat-stable salts (primarily anionic chloride ions, Cl-). - The mass concentration of the compound was 2.5%, the mass concentration of ethanolamine was 23%, the mass concentration of solid particulate matter was 0.3%, and the pH was 9.
[0114] As can be seen from the comparison of the above embodiments and comparative examples, the present application adopts a synergistic treatment of membrane filtration, membrane extraction and membrane stripping, which can effectively remove impurities such as heat-stable salts and solid particulate matter.
[0115] 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.
[0116] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. 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 scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.
Claims
1. A method for purifying decarbonized amine solution, characterized in that, Includes the following steps: The decarbonized amine solution was subjected to membrane filtration, and the amine filtrate was collected; wherein the pore size of the membrane used in the membrane filtration process was 0.01μm~0.1μm; The amine solution filtrate is subjected to membrane extraction to collect the purified amine solution; wherein the extractant used in the membrane extraction process includes an alkaline solution or water; The amine solution is subjected to membrane stripping treatment using stripping gas to collect the amine-rich solution; wherein the stripping gas includes one or more of inert gas, carbon dioxide, water vapor and air.
2. The purification method for decarbonized amine solution according to claim 1, characterized in that, The decarbonized amine solution is an aqueous solution of amine compounds; The impurities in the decarbonized amine solution include one or more of particulate matter, heat-stable salts, and volatile degradation products.
3. The purification method for decarbonized amine solution according to claim 2, characterized in that, The decarbonized amine solution includes one or more of ethanolamine solution and N-methyldiethanolamine solution.
4. The purification method for decarbonized amine solution according to claim 2, characterized in that, The steps of treating the decarbonized amine solution by membrane filtration include: Take the decarbonized amine solution at a temperature of 40℃~60℃, and let the decarbonized amine solution flow through a filter membrane with a pore size of 0.01μm~0.1μm under a pressure of 0.01MPa~0.5MPa to remove particulate matter, and collect the amine solution filtrate and retentate.
5. The purification method for decarbonized amine solution according to claim 2, characterized in that, The step of performing membrane extraction on the amine solution filtrate includes: The amine filtrate is subjected to membrane extraction using a first hollow fiber membrane, wherein the amine filtrate flows through the inside of the first hollow fiber membrane and the extract flows through the outside of the first hollow fiber membrane to remove the heat-stable salt, and the purified amine filtrate and waste extract are collected.
6. The purification method for decarbonized amine solution according to claim 5, characterized in that, The extract comprises a sodium hydroxide aqueous solution or water with a mass fraction of 1% to 5%; And / or, the first hollow fiber membrane is hydrophobic; And / or, the flow rate of the amine filtrate is 2 mL / min-5 mL / min; And / or, the flow rate of the extract is 2 mL / min to 5 mL / min; And / or, the purification method further includes: neutralizing or evaporating the waste extract into crystals.
7. The purification method for decarbonized amine solution according to claim 2, characterized in that, The steps of performing membrane stripping treatment on the purified amine solution using stripping gas include: The amine purification liquid is subjected to membrane stripping treatment using a second hollow fiber membrane, wherein the amine purification liquid flows through the interior of the second hollow fiber membrane, and the stripping gas flows through the exterior of the second hollow fiber membrane to remove the volatile degradation products and collect the amine-rich liquid and waste gas.
8. The purification method for decarbonized amine solution according to claim 7, characterized in that, The second hollow fiber membrane is hydrophobic; And / or, the flow rate of the amine purification solution is 0.3 mL / min to 6 mL / min; And / or, the flow rate of the stripping gas is 0.5 mL / min to 10 mL / min; And / or, the purification method further includes: conveying the waste gas to a waste gas scrubbing tower or to an incinerator for post-treatment.
9. The purification method for decarbonized amine solution according to any one of claims 1 to 8, characterized in that, Before the step of membrane filtration of the decarbonized amine solution, the method further includes: pre-treating the decarbonized amine solution to remove solid suspended matter from the decarbonized amine solution.
10. A purification system for decarbonized amine solution, characterized in that, A purification method for the decarbonized amine solution according to any one of claims 1 to 9, wherein the purification system comprises: A membrane filtration assembly for performing membrane filtration treatment on the decarbonized amine solution; A membrane extraction assembly for performing membrane extraction treatment on the amine filtrate; A membrane stripping unit is used to perform membrane stripping treatment on the amine purification solution.