Method for purifying powdered cation resin through combination of water washing and ion exchange methods
The purification of powdered cation exchange resin by combining water washing and ion exchange first rapidly removes soluble ions, and then further processes it through anion exchange. This solves the problem of increased hydrogen conductivity caused by the dissolution of organic matter in powdered cation exchange resin, and achieves efficient and low-cost purification results.
Patent Information
- Application Number
- CN202510819542.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-19
- Publication Date
- 2025-11-11
AI Technical Summary
In existing technologies, powdered cation exchange resins exhibit severe organic leaching during use, leading to increased hydrogen conductivity and affecting the quality of condensate. Furthermore, existing purification methods are ineffective, costly, or introduce secondary pollution.
A method for purifying powdered cation exchange resin using a water washing-ion exchange method was adopted. First, most of the soluble ions were removed by water washing. Then, the resin was mixed with granular strong basic anion exchange resin, treated at a constant temperature, separated, and the water was removed. Finally, the dissolved substances were measured.
It significantly reduces the conductivity of powdered cation exchange resin, improves the quality of the steam-water system, ensures the safe and stable operation of the unit, and is simple to operate, low in cost, and free from secondary pollution.
Smart Images
Figure CN120920087A_ABST
Abstract
Description
Technical Field
[0001] This disclosure belongs to the field of powdered cation exchange resin purification technology for condensate polishing, and specifically relates to a method for purifying powdered cation exchange resin using a combination of water washing and ion exchange. Background Technology
[0002] Northern my country is rich in coal-fired power resources but lacks water resources. Therefore, direct air cooling is commonly used for generator cooling, resulting in condensate with lower total salinity, higher iron concentration, and higher water temperature compared to wet-cooled units. Powder-coated filters, due to their strong iron filtration capacity, high-temperature resistance, and lack of need for separation and regeneration, are widely used in condensate polishing systems for air-cooled units. Powder-coated filters primarily rely on powdered resin coating the filter element skeleton to achieve ion exchange and filtration. Although powdered resin is a water-insoluble polymer, the presence of oligomers and impurities during manufacturing can lead to the leaching of organic and inorganic ions when immersed and rinsed in high-temperature water. This includes the leaching of raw materials remaining in the resin skeleton during synthesis, the leaching of degradation products from the resin skeleton itself, the shedding of active functional groups from the resin, and the leaching of dispersants and other chemicals added during the production process. The leachates from powdered cation exchange resins are mostly small sulfonic acid molecules formed by the decomposition of sulfonic acid groups, while the leachates from powdered anion exchange resins are mostly amines and neutral organic compounds. Therefore, the leachates from powdered cation exchange resins have a more severe impact on steam quality than those from powdered anion exchange resins. Studies have shown that powdered resins currently used in the field commonly leach large amounts of organic matter during the initial operation of powder-covered filters. Since this organic matter cannot be absorbed by the subsequent high-speed mixed bed, it enters the feedwater and main steam, where it decomposes under heat, leading to an increase in hydrogen conductivity. Therefore, it is necessary to propose a purification method for powdered cation exchange resins. Summary of the Invention
[0003] This disclosure aims to at least solve one of the technical problems existing in the prior art, and to provide a method for purifying powdered cation exchange resin using a combination of water washing and ion exchange.
[0004] This disclosure provides a method for purifying powdered cation exchange resin using a water washing-ion exchange method, the method comprising:
[0005] The powdered cation exchange resin was washed with water.
[0006] The powdered cation exchange resin and granular strong base anion exchange resin were mixed evenly after being washed with water and treated at a constant temperature to separate the powdered cation exchange resin and granular strong base anion exchange resin, and the water in the separated powdered cation exchange resin was removed.
[0007] The extracts from powdered cation exchange resins were determined.
[0008] Optionally, the powdered cation exchange resin is an ammonium-type powdered cation exchange resin.
[0009] Optionally, the washing of the powdered cation exchange resin with water includes:
[0010] The powdered cation exchange resin was loaded into the resin exchange column by rinsing it multiple times with ultrapure water.
[0011] Ultrapure water was introduced into the resin exchange column and the powdered cation exchange resin was rinsed using a peristaltic pump.
[0012] Optionally, the flow rate of the peristaltic pump is 10–20 mL / min; and / or,
[0013] The ratio of the mass of the powdered cation exchange resin to the volume of ultrapure water used for washing the powdered cation exchange resin is 1:100 g:mL.
[0014] Optionally, the mass ratio of the powdered cation exchange resin to the granular strong basic anion exchange resin is 3:(1-3).
[0015] Optionally, the temperature for constant temperature treatment after mixing the powdered cation exchange resin and the granular strong basic anion exchange resin is 45-55°C, and the time is 1.5-2.5 hours.
[0016] Optionally, the particulate strongly basic anion exchange resin is of the OH type; and / or,
[0017] Powdered cation exchange resin and granular strong basic anion exchange resin are separated using a sieve with a mesh size of 40-90.
[0018] Optionally, the removal of moisture from the separated powdered cation exchange resin includes:
[0019] The separated powdered cation exchange resin was loaded into a resin exchange column, and the water inside the resin exchange column was dried using a peristaltic pump.
[0020] Optionally, the determination of the extractables from the powdered cation exchange resin includes:
[0021] The conductivity content in the solution was measured after heating the powdered cation exchange resin at 70℃ for 20 hours.
[0022] Optionally, before determining the conductivity content in the solution, the method further includes:
[0023] The solution was filtered using a 0.4–0.5 μm filter.
[0024] This disclosure provides a method for purifying powdered cation exchange resin using a water washing-ion exchange method. The method includes: washing the powdered cation exchange resin with water; mixing the washed powdered cation exchange resin with granular strong basic anion exchange resin, treating at a constant temperature, separating the powdered cation exchange resin and granular strong basic anion exchange resin, and removing water from the separated powdered cation exchange resin; and measuring the extractables from the powdered cation exchange resin. This disclosure proposes a method for purifying powdered cation exchange resin using a water washing-ion exchange method, which first rapidly removes most of the soluble ions from the powdered cation exchange resin by water washing, and then further removes trace ions from the powdered cation exchange resin by ion exchange. This method is of great significance for reducing the content of extractables from powdered cation exchange resin, improving the phenomenon of excessive hydrogen conductivity in the steam-water system, and ensuring the safe and stable operation of the unit. It has the advantages of simple operation, low cost, and no secondary pollution. After purification, the conductivity of the extractables from the powdered cation exchange resin can be significantly reduced. Attached Figure Description
[0025] Figure 1 This is a flowchart illustrating a specific embodiment of the method for purifying powdered cation exchange resin using a water washing-ion exchange method.
[0026] Figure 2 This is a schematic flowchart illustrating the method for purifying powdered cation exchange resin using a water washing-ion exchange method according to a specific embodiment of this disclosure.
[0027] Figure 3 This is a comparison of the conductivity of powdered cation exchange resin A before and after purification in Example 1 of this disclosure;
[0028] Figure 4 This is a comparison of the conductivity of powdered cation exchange resin B before and after purification in Example 2 of this disclosure. Detailed Implementation
[0029] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.
[0030] like Figure 1 and Figure 2 As shown, this disclosure provides a method S100 for purifying powdered cation exchange resin using a water washing-ion exchange method, specifically including the following steps S110 to S130:
[0031] S110. Wash the powdered cation exchange resin with water.
[0032] Specifically, the washing stage includes the following steps:
[0033] (1) Weigh about 3g of powdered resin sample and place it in a pre-washed and dried beaker for later use;
[0034] (2) Transfer the powdered resin in the beaker to the resin exchange column and rinse it with ultrapure water several times until all the powdered resin is packed into the exchange column.
[0035] (3) Pass ultrapure water through the exchange column and use a peristaltic pump to adjust the flow rate to 10-20 mL / min to rinse the resin sample.
[0036] In some preferred embodiments, the powdered cation exchange resin used in the water washing stage is an ammonium-type powdered cation exchange resin.
[0037] In some preferred embodiments, during the water washing stage, the rinsing flow rate should be controlled to avoid loss of the powdered resin and the amount of rinsing water in contact with it. Throughout the water washing process, the ratio of the mass of the powdered cation exchange resin to the volume of ultrapure water used for washing the powdered cation exchange resin is 1:100 g:mL. That is, the total volume ratio of the mass of the powdered cation exchange resin, the amount of ultrapure water used to repeatedly rinse the resin into the exchange column, and the amount of ultrapure water used to rinse the exchange column is 1:100, i.e., the resin-to-water ratio is 1:100. For example, when the mass of the powdered cation exchange resin is 3g, the total volume of ultrapure water is 300mL. In the rinsing stage, the volume of ultrapure water is preferably 50mL, and in the rinsing stage, the volume of ultrapure water is preferably 250mL.
[0038] It should be noted that if the rinsing flow rate of the powdered cation exchange resin cannot reach 10-20 mL / min, the sample amount of powdered resin can be reduced to 1-1.5 g, and rinsing can be performed in 2-3 times.
[0039] In this embodiment, the water washing purification step can quickly remove most soluble ions, such as inorganic salts and low-molecular-weight organic compounds, thus initially reducing conductivity. Furthermore, the water washing treatment can reduce the pressure on the subsequent anion exchange resin and extend the service life of the granular resin.
[0040] S120. The powdered cation exchange resin and granular strong base anion exchange resin after washing are mixed evenly and treated at a constant temperature to separate the powdered cation exchange resin and granular strong base anion exchange resin, and the water in the separated powdered cation exchange resin is removed.
[0041] Specifically, the ion exchange stage includes the following steps:
[0042] (1) Use 110-140 mL of ultrapure water to completely transfer the powdered resin in the exchange column to a pre-washed and dried conical flask, add granular strong basic anion exchange resin and mix evenly, and treat in a water bath at 45-55°C for 1.5-2.5 h, for example, it is preferable to treat at 50°C for 2 h.
[0043] (2) The granular resin and powdered resin are completely separated by a sieve, and the powdered resin and soaking solution are collected in a tray.
[0044] (3) Transfer the collected powdered resin and soaking solution to the resin exchange column and use a peristaltic pump to remove the water from the exchange column.
[0045] In some preferred embodiments, the strongly basic anion exchange resin added during the ion exchange stage should be a high-performance granular resin for refining. This strongly basic anion exchange resin should be a high-performance granular resin for refining (maximum withstand temperature: 80°C; sphericity after percolation: ≥95%; volumetric exchange capacity ≥1.0 mmol / mL; uniformity coefficient ≤1.1; average crushing strength ≥900 g / particle; strong group exchange capacity reduction rate ≤10%), and the resin should be in the OH form. In this way, the sulfonic acid groups (such as -SO3H) dissolved from the powdered cation resin decompose to generate sulfonic acid organic compounds (such as benzenesulfonic acid), and the OH-type anion resin passes through the quaternary ammonium groups (-N... + (CH3)3OH-) preferentially adsorbs such anionic organic compounds, reducing the problem of excessive hydrogen conductivity caused by thermal decomposition after entering the thermal system.
[0046] In some other preferred embodiments, the mass ratio of powdered cation exchange resin to granular strong-base anion exchange resin is 3:(1-3). For example, when 3g of powdered cation exchange resin is preferred, 1-3g of granular strong-base anion exchange resin is preferred, and more preferably 1g.
[0047] In some other preferred embodiments, a sieve with a mesh size of 40 to 90 is preferred for the ion exchange stage to achieve better separation results.
[0048] In some other preferred embodiments, the content of powder resin leachates was basically stable when the heating time for measuring the powder resin leachates was selected to be 20 hours.
[0049] In this embodiment, residual ions (such as chloride ions and acid radical ions) are selectively adsorbed by anion exchange resin to further remove trace pollutants. Simultaneously, the synergistic effect of anion exchange resin and water washing compensates for the poor removal efficiency of low-concentration ions by water washing alone, improving the purity of the powdered cation exchange resin. Furthermore, the granular resin can be regenerated and reused after it has lost its effectiveness, reducing processing costs.
[0050] S130. The extracts from the powdered cation exchange resin were determined.
[0051] Specifically, the determination of dissolved substances from powdered resin includes the following steps:
[0052] (1) Use 70-80 mL of ultrapure water to completely transfer the powdered resin sample to be tested into a pre-washed and dried conical flask;
[0053] (2) Place the conical flask in an oven and heat it at 70°C for 20 hours. Then measure the conductivity content in the solution.
[0054] In some preferred embodiments, before determining the conductivity content in the solution, the method further includes filtering the solution using a 0.4–0.5 μm filter (e.g., preferably 0.45 μm). The selected conductivity meter should have a resolution of not less than 0.01 μS / cm.
[0055] This disclosure addresses the problems of poor purification effect, high processing cost, and introduction of new impurities that may occur with single purification methods for powdered cation exchange resins. It innovatively proposes a combined water washing and ion exchange method for purifying powdered cation exchange resins. Utilizing the high solubility of deionized water, soluble impurities (such as inorganic salts and low-molecular-weight organic matter) are rapidly removed from the resin surface and pores, initially reducing conductivity. Then, anion exchange resin selectively adsorbs residual ions (such as chloride ions and acid radicals), further removing trace contaminants. On the one hand, the pre-washing treatment reduces the pressure on the subsequent anion exchange resin, extending the service life of the granular resin. On the other hand, the anion exchange resin compensates for the poor removal efficiency of low-concentration ions by water washing alone, improving the purity of the powdered cation exchange resin. Furthermore, the granular resin can be regenerated and reused after it becomes ineffective, reducing processing costs. The combined water washing and ion exchange process has advantages such as simple operation, good purification effect, and no secondary pollution, and is of reference value for the preparation of low-leaching powdered cation exchange resins.
[0056] The following will further illustrate the method for purifying powdered cation exchange resin using a combination of water washing and ion exchange with specific embodiments:
[0057] Example 1
[0058] This example describes the purification of a certain powdered cation exchange resin used for condensate polishing by water washing-ion exchange, followed by a measurement of the change in conductivity of the dissolved substances. This powdered cation exchange resin is designated as Resin A, which is the powdered cation exchange resin currently used in a powder-covered filter at a power plant. The granular strong-base anion exchange resin used for purification is designated as Resin a. The performance parameters of Resin a are as follows: maximum withstand temperature: 80℃; sphericity after percolation: ≥95%; volumetric exchange capacity ≥1.0 mmol / mL; uniformity coefficient ≤1.1; average crushing strength ≥900 g / particle; strong group exchange capacity reduction rate ≤10%), and the resin type is OH.
[0059] The specific operating steps are as follows:
[0060] 1) Weigh approximately 3g of powdered resin A sample and place it in a pre-washed and dried beaker for later use;
[0061] 2) Transfer the powdered cation exchange resin taken in 1) into the resin exchange column and rinse it several times with 50mL of ultrapure water until all the powdered resin is packed into the exchange column.
[0062] 3) Pour in 250 mL of ultrapure water and use a peristaltic pump to adjust the flow rate to 15 mL / min to rinse the resin sample. Collect the eluent within 1 minute before rinsing and measure its conductivity as the initial conductivity before purification.
[0063] 4) Use 125mL of ultrapure water to completely transfer the powdered resin in the exchange column to a pre-washed and dried conical flask, add 1g of strong basic anion exchange resin a and mix well. Then, treat the mixture at 50℃ in a water bath for 2 hours to obtain the test group.
[0064] 5) Take another group and repeat the above treatment conditions (water purification treatment only) but without strengthening the alkaline anion exchange resin as a control group;
[0065] 6) The granular resin and powdered resin are completely separated by a 50-mesh sieve. The powdered resin and soaking solution are collected in a tray.
[0066] 7) Transfer the collected powdered resin and soaking solution to the resin exchange column, and use a peristaltic pump to remove the water from the exchange column.
[0067] 8) Use 75 mL of ultrapure water to completely transfer the powdered resin samples to be tested from the test group and the control group into a pre-washed and dried conical flask;
[0068] 9) Place the conical flask in an oven and heat it at 70°C for 20 hours. Then measure the conductivity content in the solutions of the experimental group and the control group.
[0069] like Figure 3As shown, the conductivity of the powdered cation exchange resin extract before purification was 152.2 μS / cm. After purification via water washing, the conductivity of the control group's powdered cation exchange resin extract decreased to 25.4 μS / cm, a reduction of 83%. After purification using a combined water washing and ion exchange method, the conductivity of the experimental group's powdered cation exchange resin extract decreased to 13.45 μS / cm, a reduction of 91%. This demonstrates that water washing can rapidly remove most soluble ions from the powdered cation exchange resin, while the combined water washing and ion exchange method can further remove trace ions from the powdered cation exchange resin and its extract. The conductivity of the powdered cation exchange resin extract after water purification alone was approximately 1.9 times that after purification using the combined water washing and ion exchange method.
[0070] Example 2
[0071] This example describes the purification of a certain powdered cation exchange resin used for condensate polishing by water washing-ion exchange, followed by measurement of the change in conductivity of the dissolved substances. This powdered cation exchange resin is designated as Resin B, which is the powdered cation exchange resin currently used in a powder-covered filter at a power plant. The granular strong-base anion exchange resin used for purification is designated as Resin A. Similarly, the performance parameters of Resin A are as follows: maximum withstand temperature: 80℃; sphericity after percolation: ≥95%; volumetric exchange capacity ≥1.0mmol / mL; uniformity coefficient ≤1.1; average crushing strength ≥900g / particle; strong group exchange capacity reduction rate ≤10%; and the resin type is OH.
[0072] The specific operating steps are as follows:
[0073] 1) Weigh approximately 3g of powdered resin B sample and place it in a pre-washed and dried beaker for later use;
[0074] 2) Transfer the powdered cation exchange resin taken in 1) into the resin exchange column and rinse it several times with 50mL of ultrapure water until all the powdered resin is packed into the exchange column.
[0075] 3) Pour in 250 mL of ultrapure water and use a peristaltic pump to adjust the flow rate to 15 mL / min to rinse the resin sample. Collect the eluent within 1 minute before rinsing and measure its conductivity as the initial conductivity before purification.
[0076] 4) Use 125mL of ultrapure water to completely transfer the powdered resin in the exchange column to a pre-washed and dried conical flask, add 1g of strong basic anion exchange resin a and mix well. Then, treat the mixture at 50℃ in a water bath for 2 hours to obtain the test group.
[0077] 5) Take another group and repeat the above treatment conditions (water purification treatment only) but without strengthening the alkaline anion exchange resin as a control group;
[0078] 6) The granular resin and powdered resin are completely separated by a 50-mesh sieve. The powdered resin and soaking solution are collected in a tray.
[0079] 7) Transfer the collected powdered resin and soaking solution to the resin exchange column, and use a peristaltic pump to remove the water from the exchange column.
[0080] 8) Use 75 mL of ultrapure water to completely transfer the powdered resin samples to be tested from the test group and the control group into a pre-washed and dried conical flask;
[0081] 9) Place the conical flask in an oven and heat it at 70°C for 20 hours. Then measure the conductivity content in the solutions of the experimental group and the control group.
[0082] like Figure 4 As shown in the results, the conductivity of the B powder cation exchange resin extract before purification was 199 μS / cm. After purification via water washing, the conductivity of the control group powder cation exchange resin extract decreased to 34 μS / cm, a reduction rate of 83%. After purification using a combined water washing and ion exchange method, the conductivity of the experimental group powder cation exchange resin extract decreased to 25 μS / cm, a reduction rate of 87%. Therefore, the conductivity of the powder cation exchange resin extract after water purification alone is approximately 1.4 times that of the extract after purification using the combined water washing and ion exchange method.
[0083] It is worth noting that due to differences in the manufacturing and production processes of powdered resins, the leachate content of powdered cation exchange resin B is higher than that of powdered cation exchange resin A. Therefore, under the same treatment method, the treatment effect of powdered cation exchange resin B is not as good as that of powdered cation exchange resin A. When the initial conductivity of the powdered cation exchange resin is high, the quality of the granular strong basic anion exchange resin can be appropriately increased or the treatment time can be extended to obtain better treatment results.
[0084] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.
Claims
1. A method for purifying powdered cation exchange resin using a water washing-ion exchange method, characterized in that, The method includes: The powdered cation exchange resin was washed with water. The powdered cation exchange resin and granular strong base anion exchange resin were mixed evenly after being washed with water and treated at a constant temperature to separate the powdered cation exchange resin and granular strong base anion exchange resin, and the water in the separated powdered cation exchange resin was removed. The extracts from powdered cation exchange resins were determined.
2. The method according to claim 1, characterized in that, The powdered cation exchange resin is an ammonium-type powdered cation exchange resin.
3. The method according to claim 1, characterized in that, The washing of the powdered cation exchange resin with water includes: The powdered cation exchange resin was loaded into the resin exchange column by rinsing it multiple times with ultrapure water. Ultrapure water was introduced into the resin exchange column and the powdered cation exchange resin was rinsed using a peristaltic pump.
4. The method according to claim 3, characterized in that, The flow rate of the peristaltic pump is 10–20 mL / min; and / or, The ratio of the mass of the powdered cation exchange resin to the volume of ultrapure water used for washing the powdered cation exchange resin is 1:100 g:mL.
5. The method according to claim 1, characterized in that, The mass ratio of the powdered cation exchange resin to the granular strong basic anion exchange resin is 3:(1-3).
6. The method according to claim 1, characterized in that, The powdered cation exchange resin and the granular strong basic anion exchange resin are mixed and then subjected to constant temperature treatment at 45-55°C for 1.5-2.5 hours.
7. The method according to claim 1, characterized in that, The particulate strongly basic anion exchange resin is of the OH type; and / or, Powdered cation exchange resin and granular strong basic anion exchange resin are separated using a sieve with a mesh size of 40-90.
8. The method according to claim 1, characterized in that, The removal of moisture from the separated powdered cation exchange resin includes: The separated powdered cation exchange resin was loaded into a resin exchange column, and the water inside the resin exchange column was dried using a peristaltic pump.
9. The method according to claim 1, characterized in that, The determination of the extracts from the powdered cation exchange resin includes: The conductivity content in the solution was measured after heating the powdered cation exchange resin at 70℃ for 20 hours.
10. The method according to claim 9, characterized in that, Before determining the conductivity content in the solution, the method further includes: The solution was filtered using a 0.4–0.5 μm filter.