Determination method of resin dissolved substance

Abstract

The invention discloses a method for determining a resin dissolved substance, which can thoroughly convert the resin dissolved substance into a sulfate radical, characterize the content of the sulfate radical in the dissolved substance and predict and analyze the influence in a subsequent water vapor system. Compared with single ultraviolet UV digestion or H2O2 digestion, the digestion is not thorough; the method has the advantages that organic matters in the resin dissolved-out substances can be thoroughly digested by the aid of ultraviolet (UV) / Fenton oxidation processes, accordingly, the content of SO4 < 2-> generated by degradation of the resin dissolved-out substances in thermodynamic systems can be easily represented, and the dissolution characteristics of the resin can be accurately and effectively evaluated by the aid of the method.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical water treatment in power plants, and in particular relates to a method for determining resin extracts. Background Art

[0002] The high-speed mixed-bed cation exchange resin commonly used in condensate treatment is a styrene-based strong acid resin, whose main organic dissolution is organic sulfonate and a small amount of SO4 2- Organic sulfonates will decompose and produce a large amount of SO4 under conditions of oxidation or high temperature and high pressure. 2- , and continues to concentrate in the water vapor system, increasing the risk of stress corrosion in the metal material system, thus affecting the safe operation of the unit. 2- It is very harmful to the thermal system of power plants, especially the special materials used in nuclear power plant steam generators and other equipment, and the requirements for water vapor quality are more stringent. Condensate polishing mixed bed effluent SO4 2- The mass concentration needs to be less than 0.2μg / L. Therefore, to solve the SO4 2- In order to understand how exceeding the standard affects equipment corrosion, it is necessary to conduct research on the detection methods of cationic resin dissolution characteristics and dissolution content.

[0003] At present, the detection of resin dissolution mainly describes the dissolution characteristics of resin from the perspective of organic matter (such as chemical oxygen demand COD or total organic carbon TOC content), but cannot directly express the SO4 produced by lipid dissolution. 2- content.

[0004] Therefore, the resin extract needs to be oxidized and degraded to allow the organic sulfonate to decompose into SO4 2- , then according to SO4 2- concentration to characterize the dissolution characteristics of the resin and evaluate the SO4 generated by the degradation of the resin in the thermal system 2- However, the traditional oxidation method uses common chemical oxidants such as ozone, H2O2, etc. to decompose organic matter, but the oxidation time is long and it is difficult to completely oxidize. At present, it is still necessary to find new methods to characterize the dissolution characteristics of resins and evaluate the SO4 generated by resin dissolution. 2- Hazards to thermal systems. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a method for determining resin extracts.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for determining resin extracts, characterized in that: it comprises:

[0009] Add dilute hydrochloric acid to the resin solution to adjust the pH value of the solution;

[0010] Add H2O2 solution and FeCl2 solution;

[0011] After the volume is fixed, stir evenly, turn on the UV lamp, and react for 30 minutes;

[0012] NaOH solution was added dropwise to adjust the pH value, and then UV light was turned on for 10 min to remove the residual H2O2;

[0013] After the reaction is completed, the solution is cooled to room temperature and sampled for determination.

[0014] As a preferred embodiment of the determination method of the present invention, the concentration of the dilute hydrochloric acid is 0.1 mol / L, and the pH value of the solution is adjusted to 3.0 by adding dilute hydrochloric acid.

[0015] As a preferred embodiment of the determination method of the present invention, the volume ratio of the resin dissolution solution, the H2O2 solution and the FeCl2 solution is 50:1:1.

[0016] As a preferred embodiment of the determination method of the present invention, the concentration of the H2O2 solution is 5-10 mmol / L, and the concentration of the FeCl2 solution is 0.05-0.1 mmol / L.

[0017] As a preferred embodiment of the determination method of the present invention, the mixture is stirred evenly after volume determination, wherein the stirring speed is 200 to 250 r / min.

[0018] As a preferred embodiment of the determination method of the present invention, the concentration of the NaOH solution is 0.1-0.2 mol / L, and the NaOH solution is added to adjust the pH value to 11.0.

[0019] As a preferred embodiment of the measuring method of the present invention, the power of the ultraviolet lamp is adjusted to 30-40W.

[0020] Another object of the present invention is to overcome the shortcomings of the prior art and provide a device for measuring resin extracts, characterized in that the device includes an ultraviolet digestion device for organic matter in water and a magnetic stirrer, the magnetic stirrer is located below the ultraviolet digestion device for organic matter in water, and there is an ultraviolet lamp on each of the front, back, left and right sides of the reaction container, and the outside is a stainless steel plate.

[0021] Beneficial effects of the present invention:

[0022] The present invention provides a novel oxidation digestion method for cationic resin eluate, which can completely convert the eluate into sulfate radicals, characterize the sulfate radical content of the eluate, and predict and analyze the influence on the subsequent water vapor system.

[0023] Compared with single UV digestion or H2O2 digestion, which is not thorough, the combination of UV / Fenton oxidation method can more thoroughly digest the organic matter in the resin dissolution and more easily characterize the SO4 produced by the degradation of the resin dissolution in the thermal system. 2- The determination content can more accurately and effectively evaluate the dissolution characteristics of the resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0025] Figure 1 This is the ultraviolet light digestion device used in the embodiment of the present invention.

[0026] Figure 2 The figure is a comparison chart of the results of the embodiments of the present invention.

[0027] Figure 3 This is a diagram showing the measurement results of Comparative Example 1 of the present invention.

[0028] Figure 4 This is a diagram showing the measurement results of Comparative Example 2 of the present invention.

[0029] Figure 5 This is a diagram showing the measurement results of Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0031] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0032] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0033] Example 1

[0034] (1) Pipette 50 mL of the resin solution into a 100 mL volumetric flask and add dilute hydrochloric acid (0.1 mol / L) to adjust the pH value of the solution to 3.0;

[0035] (2) Add H2O2 solution to make its concentration 5mmol / L; add FeCl2 solution (10mmol / L) to make its concentration 0.1mmol / L;

[0036] (3) Add ultrapure water to make up the volume, transfer the solution to a 100 mL quartz flat-bottom test tube, set the constant temperature stirrer (50°C) at 200 r / min, turn on the UV lamp (30 W), and react for 30 min;

[0037] (4) Add NaOH solution (0.1 mol / L) to adjust the pH to about 11.0

[0038] (5) Turn on the UV lamp for 10 min to remove residual H2O2;

[0039] (6) After the reaction is completed, wait for the solution to cool to room temperature and take a sample for measurement.

[0040] This embodiment uses an ultraviolet light digestion device such as Figure 1 As shown, there is a magnetic stirrer below the ultraviolet digestion device for organic matter in water, and an ultraviolet lamp (rated power 40W) is arranged on the front, back, left and right sides of the reaction container, and the outside is a stainless steel plate.

[0041] Example 2

[0042] (1) Pipette 50 mL of the resin solution into a 100 mL volumetric flask and add dilute hydrochloric acid (0.1 mol / L) to adjust the pH value of the solution to 3.0;

[0043] (2) Add ultrapure water to make up the volume, transfer the solution to a 100 mL quartz flat-bottom test tube, set the constant temperature stirrer speed to 200 r / min, turn on the UV lamp, and react for 30 min;

[0044] (3) Add 4 mL of NaOH solution (0.1 mol / L) to adjust the pH to about 11.0

[0045] (4) Turn on the UV lamp for 10 min to remove residual H2O2;

[0046] (5) After the reaction is completed, wait for the solution to cool to room temperature and take a sample for measurement.

[0047] Example 3

[0048] (1) Pipette 50 mL of the resin solution into a 100 mL volumetric flask and add dilute hydrochloric acid (0.1 mol / L) to adjust the pH value of the solution to 3.0;

[0049] (2) Add 1 mL of H2O2 solution (1 mol / L) to make the concentration 10 mmol / L;

[0050] (3) Add 1 mL of FeCl2 solution (10 mmol / L) to make the concentration 0.1 mmol / L;

[0051] (4) Add ultrapure water to make up the volume, transfer the solution to a 100 mL quartz flat-bottom test tube, set the constant temperature stirrer speed to 200 r / min, and react for 30 min;

[0052] (5) Turn on the UV lamp for 10 min to remove residual H2O2;

[0053] (6) After the reaction is completed, wait for the solution to cool to room temperature and take a sample for measurement.

[0054] Example 4

[0055] In this example, the content of element S in the dissolution solutions of Examples 1 to 3 was determined by inductively coupled plasma-mass spectrometry to determine whether the sulfonic acid groups in the resin dissolution were completely degraded, and further confirm the determination of SO4 in the resin dissolution. 2- accuracy and reliability of the method.

[0056] In order to achieve complete degradation of the sulfonic acid groups in the dissolution, an excess of H2O2 needs to be added. After the degradation process is completed, there is still residual H2O2 in the dissolution solution. The SO4 in the dissolution solution is detected by ion chromatography. 2- At high concentrations, H2O2 will damage the separation tube. Therefore, it is proposed to use ultraviolet catalytic decomposition to completely remove the residual H2O2 in the dissolution solution, and use the color reaction of starch potassium iodide solution and H2O2 to determine whether there is residual H2O2.

[0057] The results are as follows Figure 2As shown in the figure, it can be seen that for the UV / Fenton system, the organic matter is almost completely degraded, and SO4 2- The mass concentration increased significantly, which shows that the effect of UV and Fenton's reagent combined is far greater than simple superposition, and the two produce a synergistic effect, namely, Fe 2+ The UV and H2O2 jointly catalyze the decomposition of hydroxyl radicals (HO·), which react with organic sulfonates to effectively degrade organic matter, and the sulfonic acid groups are oxidized to SO4 2- Release it.

[0058] The degradation of organic matter and the amount of sulfate produced were compared using three digestion methods. The results are as follows: Figure 2 As shown, it can be seen that when using UV alone for 30 minutes or Fenton alone, the extent of TOC degradation is lower than that of the UV / Fenton method, and the sulfate ion concentration generated is about 60% of that of the UV / Fenton method.

[0059] Comparative Example 1

[0060] The difference between this embodiment and embodiment 1 is that the power of the ultraviolet lamp in step (3) is replaced by 0W, 10W, 20W, and 40W respectively, and the remaining steps are the same as those in embodiment 1.

[0061] The dissolution solutions of Example 1 and Comparative Example 1 were measured using the method of Example 4. The results are as follows: Figure 3 As shown in the figure, it can be seen that the degradation effect of organic matter is not ideal when UV light is not introduced. When UV light is introduced into the system, the TOC content drops rapidly to a lower level. When the UV lamp power increases from 30W to 40W, the degradation rate of organic matter and SO4 2- The concentration hardly changes, so the UV lamp power is preferably 30-40W.

[0062] Comparative Example 2

[0063] The difference between this embodiment and embodiment 1 is that the concentration of H2O2 solution in step (2) is replaced by 0.1mmol / L, 0.5mmol / L, 1.0mmol / L, and 10mmol / L, respectively, and the remaining steps are the same as those in embodiment 1.

[0064] The method of Example 4 was used to measure the dissolution solutions of Example 1 and Comparative Example 2. The results are as follows: Figure 4 As shown in the figure, it can be seen that with the increase of H2O2 concentration, the degradation of organic matter first increases sharply and then slowly tends to be stable. At the beginning, the H2O2 concentration in the solution is low. As the H2O2 concentration increases, the HO· content increases, which makes the degradation rate of organic matter increase accordingly. 2-When the concentration of H2O2 increases to a certain extent, H2O2 reacts with excessive HO· to ​​generate HOO· with weaker oxidizing properties, which in turn inhibits the degradation of organic matter and causes its degradation rate to decrease. Therefore, the concentration of H2O2 solution is preferably 5-10 mmol / L.

[0065] Comparative Example 3

[0066] The difference between this embodiment and embodiment 1 is that the pH values ​​in step (2) are replaced by 2.0, 4.0, 5.0, and 6.0, respectively, and the remaining steps are the same as those in embodiment 1.

[0067] The method of Example 4 was used to measure the dissolution solutions of Example 1 and Comparative Example 3. The results are as follows: Figure 5 As shown in the figure, it can be seen that as the pH value increases, the TOC degradation rate and SO4 2- The concentration increases first and then decreases. + Higher concentration, Fe 3+ Difficult to convert into Fe, which has a stronger catalytic effect 2+ , resulting in the inhibition of HO· production, which reduces the degradation rate of organic matter; when the pH value is high, H2O2 molecules are unstable and easily decomposed, thus losing their oxidizing ability. At the same time, Fe 2+ with Fe 3 + , a hydrolysis reaction will occur to generate Fe(OH)2 and Fe(OH)3 without catalytic ability, which will reduce the production of HO·, reduce the degradation rate of organic matter, and reduce the SO4 2- The content is reduced.

[0068] The present invention provides a novel oxidation digestion method for cationic resin eluate, which can completely convert the eluate into sulfate radicals, characterize the sulfate radical content of the eluate, and predict and analyze the influence on the subsequent water vapor system.

[0069] Compared with single UV digestion or H2O2 digestion, which is not thorough, the combination of UV / Fenton oxidation method can more thoroughly digest the organic matter in the resin dissolution and more easily characterize the SO4 produced by the degradation of the resin dissolution in the thermal system. 2- The determination content can more accurately and effectively evaluate the dissolution characteristics of the resin.

[0070] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A method for determining resin extracts, characterized in that: include, Add dilute hydrochloric acid to the resin solution to adjust the pH value of the solution; Add H2O2 solution and FeCl2 solution; After the volume is fixed, stir evenly, turn on the UV lamp, and react for 30 minutes; NaOH solution was added dropwise to adjust the pH value, and then UV light was turned on for 10 min to remove the residual H2O2; After the reaction is completed, the solution is cooled to room temperature and sampled for determination.

2. The assay method according to claim 1, wherein: The concentration of the dilute hydrochloric acid is 0.1 mol / L, and the pH value of the solution is adjusted to 3.0 by adding dilute hydrochloric acid.

3. The assay method according to claim 1, wherein: The volume ratio of the resin dissolution solution, H2O2 solution and FeCl2 solution is 50:1:

1.

4. The assay method according to claim 3, wherein: The concentration of the H2O2 solution is 5-10 mmol / L, and the concentration of the FeCl2 solution is 0.05-0.1 mmol / L.

5. The assay method according to claim 1, wherein: After the volume is fixed, the mixture is stirred evenly, wherein the stirring speed is 200-250 r / min and the temperature is 40-60° C.

6. The assay method according to claim 1, wherein: The concentration of the NaOH solution is 0.1-0.2 mol / L, and the pH value is adjusted to 11.0 by adding the NaOH solution.

7. The assay method according to claim 1, wherein: The power of the ultraviolet lamp is adjusted to 30-40W.

8. A device for measuring resin extract, characterized in that: The device comprises an ultraviolet digestion device for organic matter in water and a magnetic stirrer. The magnetic stirrer is located below the ultraviolet digestion device for organic matter in water. A reaction container is provided with an ultraviolet lamp at the front, back, left and right sides respectively, and the exterior is a stainless steel plate.

Images