Method for evaluating impurity ion dissolved substance level of inert fiber powder

Abstract

The invention provides a method for evaluating the impurity ion dissolved-out substance level of inert fiber powder, and belongs to the technical field of power plant condensation water treatment. The method comprises the following steps: soaking inert fiber powder in high-temperature and high-purity water; carrying out full-spectrum analysis on anions and cations in the soak solution by adopting an ion chromatography to respectively obtain the mass concentrations of the anions and the cations; respectively calculating dissolution indexes of the anions and the cations according to the mass concentrations of the anions and the cations; and judging whether the cation dissolution index is smaller than a cation dissolution index threshold value or not and whether the anion dissolution index is smaller than an anion dissolution index threshold value or not so as to obtain an evaluation result of the impurity ion dissolution substance level of the inert fiber powder. The impurity ion content of the inert fiber powder can be rapidly and accurately evaluated through the anion dissolution index and the cation dissolution index, the bias of judging the quality of the fiber powder only by depending on a single ion index is avoided, and the evaluation accuracy and reliability are improved.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of condensate treatment in power plants, and particularly relates to a method for evaluating the ion impurity dissolution level of inert fiber powder. BACKGROUND

[0002] Powder-covered filters are widely used in condensate polishing systems, and their core function relies on the synergistic effect of powder ion exchange resins and inert fiber powder. Through ion exchange and physical filtration, the powder-covered filters remove dissolved impurities and suspended particles in water. However, both powder cation and anion exchange resins and inert fiber powder will dissolve impurity ions during use. Since the powder ion exchange resin itself has ion exchange function, the content of impurity ions dissolved by it is relatively small. In contrast, the content of impurity ions dissolved by fiber powder is often several orders of magnitude higher than that of powder cation and anion resins. These dissolved impurity ions increase the conductivity of the boiler water, which in turn affects the operating efficiency of the boiler and the quality of the steam. Therefore, it is necessary to evaluate the impurity ion dissolution content of inert fiber powder.

[0003] Currently, there is no unified control standard for the impurity ion dissolution of inert fiber powder in existing literature and industrial practice. The dissolution of fiber powder is diverse, and the dissolution content of fiber powder of different brands and batches differs greatly, making it difficult to be comprehensively evaluated by a single index. Secondly, existing methods focus on the dissolution of a single ion, ignoring the overall impact of fiber powder dissolution. Only detecting the content of chloride ions cannot comprehensively reflect the comprehensive impact of fiber powder dissolution on the quality of boiler water. In addition, the existing methods have limitations in practical application, and cannot quickly and accurately evaluate the overall dissolution level of fiber powder, making it difficult to meet the needs of rapid detection and quality control in industrial sites. SUMMARY

[0004] The present disclosure aims to at least solve one of the technical problems existing in the prior art, and provides a method for evaluating the ion impurity dissolution level of inert fiber powder.

[0005] The present disclosure provides a method for evaluating the ion impurity dissolution level of inert fiber powder, which comprises:

[0006] immersing the inert fiber powder in high-temperature high-purity water;

[0007] performing full-spectrum analysis of anions and cations in the immersion solution by ion chromatography to obtain the mass concentrations of anions and cations, respectively;

[0008] calculating the dissolution indexes of anions and cations, respectively, according to the mass concentrations of anions and cations;

[0009] determining whether the cation elution index is less than a cation elution index threshold value and whether the anion elution index is less than an anion elution index threshold value to obtain the inert fiber powder impurity ion eluate level evaluation result.

[0010] Optionally, the temperature of the inert fiber powder soaking in the high-purity water is 65-75℃, and the soaking time is 1.5-3h.

[0011] Optionally, the mass ratio of the inert fiber powder to the high-purity water is 1:(45-55).

[0012] Optionally, the temperature of the inert fiber powder soaking in the high-purity water is 70℃, and the soaking time is 2h.

[0013] The mass ratio of the inert fiber powder to the high-purity water is 1:50.

[0014] Optionally, the cation elution index is calculated by the following formula:

[0015]

[0016] In the formula, CDI is the elution index of the impurity cation in the soaking solution, n represents the number of cation types, k i is the conductivity contribution value of the measured cation in the soaking solution, C i is the mass concentration of the measured cation in the soaking solution, Λ m is the limiting molar conductivity of the measured cation, M i is the molar mass of the cation.

[0017] Optionally, the impurity cations in the inert fiber powder include Na + , K + , Mg 2+ , and Ca 2+ .

[0018] Optionally, the anion elution index is calculated by the following formula:

[0019]

[0020] In the formula, ADI is the elution index of the impurity anion in the soaking solution, n represents the number of anion types, k j is the conductivity contribution value of the measured anion in the soaking solution, C j is the mass concentration of the measured anion in the soaking solution, Λ m is the limiting molar conductivity of the measured anion, M j is the molar mass of the anion.

[0021] Optionally, the impurity anions in the inert fiber powder include Cl - and SO42- , NO3 - .

[0022] Optionally, the cation elution index threshold is 6 μS / cm.

[0023] The anion elution index threshold is 2 μS / cm.

[0024] Optionally, before the anions in the soaking solution are analyzed by ion chromatography, the method

[0025] Further comprising:

[0026] The soaking solution is filtered by using a filter membrane with a pore size of 0.4-0.5 μm.

[0027] The present disclosure provides a method for evaluating the impurity ion elution level of inert fiber powder, which comprises: soaking the inert fiber powder in high-temperature high-purity water; performing full-spectrum analysis of the anions and cations in the soaking solution by ion chromatography to obtain the mass concentrations of the anions and cations, respectively; calculating the elution indexes of the anions and cations, respectively, according to the mass concentrations of the anions and cations; determining whether the cation elution index is less than the cation elution index threshold and whether the anion elution index is less than the anion elution index threshold to obtain the evaluation result of the impurity ion elution level of the inert fiber powder. The present disclosure can quickly and accurately evaluate the impurity ion content of the inert fiber powder through the anion elution index and the cation elution index. This method avoids the bias of relying only on a single ion index to judge the quality of the fiber powder by comprehensively evaluating the contribution of multiple elution ions, thereby improving the accuracy and reliability of the evaluation. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The flowchart of the method for evaluating the impurity ion elution level of the inert fiber powder is shown in the specific embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] To enable those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure is further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and are part of the embodiments of the present disclosure, but not all the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present disclosure.

[0030] As Figure 1 shown, the present disclosure provides a method S100 for evaluating the impurity ion elution level of inert fiber powder, which specifically comprises the following steps S110-S140:

[0031] S110, soaking the inert fiber powder in high-temperature high-purity water.

[0032] Specifically, high-purity water is first added to the conical flask, and the conical flask is placed in a water bath shaker and heated to 65-75℃. Then, according to the mass ratio of inert fiber powder to high-purity water of 1:(45-55), the dry inert fiber powder is accurately weighed and added to the high-purity water heated to 65-75℃. Finally, the conical flask is placed in a water bath shaker at 65-75℃ and shaken for 1.5-3h.

[0033] In step S110, the temperature of the inert fiber powder soaking in high-purity water can be preferably 70℃, and the time can be preferably 2h. By soaking the inert cellulose powder in high-temperature high-purity water for a certain period of time, the impurity ions are fully leached out. It should be noted that the soaking temperature of the inert fiber powder here matches the condensate water temperature of the power plant.

[0034] In step S110, the mass ratio of inert fiber powder to high-purity water can be preferably 1:50.

[0035] S120, using ion chromatography to analyze the anions and cations in the soaking solution, and obtaining the mass concentrations of anions and cations respectively.

[0036] It should be noted that before using ion chromatography to analyze the anions in the soaking solution, the method further includes: filtering the soaking solution with a filter membrane of 0.4-0.5μm (for example, 0.45μm can be preferred), which can intercept larger non-ionic substances such as suspended particles and colloids that may exist in the soaking solution, so that the soaking solution enters the ion chromatograph in the form of a relatively pure ionic solution. That is, the soaking solution should be filtered with a filter membrane before testing on the ion chromatograph.

[0037] S130, according to the mass concentrations of anions and cations, respectively calculating the leaching indexes of anions and cations.

[0038] It should be noted that the content of anions and cations in water is directly reflected by the conductivity, and each ion has its own molar conductivity. In an infinitely diluted aqueous environment, the ion mass concentration can be converted into conductivity value. The sum of the conductivity values of each anion in water is defined as the ADI index, and the sum of the conductivity values of each cation in water is defined as the CDI index, which quantifies the comprehensive influence of multiple ions on water quality.

[0039] Specifically, the leaching index of cations is calculated using the following formula:

[0040]

[0041] In the formula, CDI is the leaching index of impurity cations in the soaking solution, μS / cm.

[0042] n represents the number of cation species;

[0043] k i is the conductivity contribution value of the measured cation in the soaking solution, μS / cm;

[0044] C i is the mass concentration of the measured cation in the soaking solution (ion chromatography detection result), μg / L;

[0045] Λ m is the limiting molar conductivity of the measured cation, μS·cm 2 / μmol;

[0046] M i is the molar mass of the cation, g / mol.

[0047] That is, the cation leaching index is the sum of the conductivity values of various cations in the soaking solution, and each cation leaching index is obtained based on the mass concentration measured in step S120 and its molar mass and limiting molar conductivity.

[0048] It should be noted that the impurity cations in the inert fiber powder include Na + , K + , Mg 2+ , Ca 2+ , and of course, other impurity cations may also exist in the soaking solution, but their content is low, and the above several cations can be used as the main calculation of the cation leaching index.

[0049] Further, the anion leaching index is calculated using the following formula:

[0050]

[0051] In the formula, ADI is the leaching index of the impurity anion in the soaking solution, μS / cm;

[0052] n represents the number of anion species;

[0053] k j is the conductivity contribution value of the measured anion in the soaking solution, μS / cm;

[0054] C j is the mass concentration of the measured anion in the soaking solution (ion chromatography detection result), μg / L;

[0055] Λ m is the limiting molar conductivity of the measured anion, μS·cm 2 / μmol;

[0056] Mj Molar mass of anion, g / mol.

[0057] That is, the anion dissolved index is the sum of the conductivity values of various anions in the immersion liquid, and each anion dissolved index is obtained based on the mass concentration measured in step S120, the molar mass, and the limiting molar conductivity.

[0058] It should be noted that the impurity anions in the inert fiber powder include Cl - , SO4 2- , NO3 - , and similarly, other impurity anions may also exist in the immersion liquid, but their content is low, and the cation dissolved index can be calculated mainly based on the above several anions.

[0059] S140, determining whether the cation dissolved index is less than the cation dissolved index threshold value and whether the anion dissolved index is less than the anion dissolved index threshold value to obtain the inert fiber powder impurity ion dissolved level evaluation result.

[0060] In step S140, the cation dissolved index threshold value is 6 μS / cm, and the anion dissolved index threshold value is 2 μS / cm. That is, when the calculated cation dissolved index is less than 6 μS / cm and the anion dissolved index is less than 2 μS / cm, it indicates that the inert fiber powder impurity ion dissolved level meets the requirements. If the above two conditions are not met, it indicates that the inert fiber powder impurity ion dissolved level is high and does not meet the requirements.

[0061] It should be noted that the evaluation method of the present embodiment is applicable to new inert fiber powder that has not been put into use. It is not applicable to samples that have been put into operation, because the samples after operation may be affected by various complex factors (such as reaction with other substances, adsorption of impurities in the operating environment, etc.), and the impurity ion dissolution cannot be simply measured by this standard.

[0062] The present embodiment proposes an evaluation method for the inert fiber powder impurity ion dissolved level that is comprehensive, fast, and applicable to industrial sites. Through the anion dissolved index (ADI) and the cation dissolved index (CDI), the inert fiber powder impurity ion content can be quickly and accurately evaluated. This method avoids the bias of relying on a single ion index to judge the quality of the fiber powder by comprehensively evaluating the contribution of multiple dissolved ions, improves the accuracy and reliability of the evaluation, provides a scientific basis for water treatment of the boiler system, and ensures the water quality of the boiler and the safe operation of the boiler.

[0063] The method for evaluating the ion leachate level of inert fiber powder impurities will be further illustrated below in combination with specific examples:

[0064] Example 1

[0065] This example selects one foreign and two domestic fiber powder products, all of which are new inert fiber powders that have not been put into use. The imported sample is marked as brand A fiber powder, and the domestic samples are marked as brand B fiber powder and brand C fiber powder. The highest condensate temperature treated by a certain power plant per year is 70°C, so the evaluation temperature of the high-temperature soaking stage is set to 70°C, and the specific operation steps are as follows:

[0066] (1) High-temperature soaking: Prepare three 250 mL conical flasks, measure a certain amount of high-purity water into the conical flasks with a graduated cylinder, and heat the conical flasks to 70°C in a water bath shaker. Then, according to the mass ratio of inert fiber powder to high-purity water of 1:50, accurately weigh the dry weight of brand A fiber powder, brand B fiber powder, and brand C fiber powder, and add them to the three conical flasks, respectively. Finally, under the condition of 70°C, place the conical flasks in a water bath shaker and shake for 2 h.

[0067] (2) Impurity ion detection: Detect the anion and cation content in the soaking solution of brand A fiber powder, brand B fiber powder, and brand C fiber powder, respectively. Use ion chromatography to perform full-spectrum analysis of anions and cations in the soaking solution, and obtain the mass concentration of each cation as shown in Table 1, and the mass concentration of anions as shown in Table 2.

[0068] Table 1 Ion chromatography results of fiber powder soaking solution (unit: mg / L)

[0069] Sample name Na + ]] NH4 + ]]> K + ]]> Mg 2+ ]] Ca 2+ <!-- 4 -->]]> Brand A 0.920 0.078 0.160 0.136 0.774 Brand B 2.220 <0.020 0.258 0.045 0.308 Brand C 2.420 <0.020 0.182 0.024 0.188

[0070] Table 2 Ion chromatography results of fiber powder soaking solution (unit: mg / L)

[0071] Sample name F - ]]> Cl - ]]> SO4 2- ]]> NO3 - ]]> PO4 3- ]] NO2 - ]]> Brand A <0.006 0.427 0.626 0.069 <0.051 <0.016 Brand B 0.012 0.409 0.813 0.037 <0.051 <0.016 Brand C <0.006 0.847 0.383 0.150 <0.051 <0.016

[0072] (3) Leaching index calculation:

[0073] Method for calculating ion leaching index:

[0074]

[0075] In formula (1):

[0076] k x — The conductivity contribution value of a certain ion in the soaking solution, μS / cm;

[0077] C x — The mass concentration of a certain ion in the soaking solution (ion chromatography detection result), μg / L;

[0078] Λ m Limit molar conductivity of certain ion determined, μS·cm 2 / μmol

[0079] M - Molar mass of certain ion determined, g / mol;

[0080] According to the detection results of impurity ions, the cations in the fiber powder leachate are mainly Na + , K + , Mg 2+ , Ca 2+ , and the anions are mainly Cl - , SO4 2- , NO3 - , so only the above ions are calculated when calculating the leachate index:

[0081]

[0082] CDI - Leaching index of impurity cations in the soaking solution, μS / cm;

[0083] ADI - Leaching index of impurity anions in the soaking solution, μS / cm;

[0084] According to the above formula, the anion and cation leaching indexes are calculated, and the results are shown in Table 3.

[0085] Table 3 Calculation results of leachate index

[0086]

[0087] (4) Threshold evaluation: The three brands of fiber powder were all subjected to industrial experiments in the power plant, among which the application effect of brand A fiber powder and brand B fiber powder after film laying was good, and the boiler water quality met the standard requirements, the hydrogen conductivity requirement was less than 1.5 μS / cm, and the chlorine ion content requirement was less than 0.5 mg / L, and the boiler water conductivity of brand C fiber powder after film laying exceeded the standard. Therefore, the anion leaching index threshold is set to 2 μS / cm, and the cation leaching index threshold is set to 6 μS / cm. Compare the calculated CDI value and ADI value with the threshold value to evaluate the impurity ion leaching level of the inert fiber powder. The specific evaluation method is as follows:

[0088] ADI < 2 μS / cm and CDI < 6 μS / cm.

[0089] Based on the above evaluation methods, it is known that the cation and anion dissolution indices of Brand A are both below the threshold, indicating a low level of dissolved substances. The cation and anion dissolution indices of Brand B are also below the threshold, although close to it; the level of dissolved substances is slightly higher than Brand A, but still meets the requirements. Brand C's ADI (2.15 μS / cm) exceeds the ADI threshold (2 μS / cm), indicating a relatively high level of dissolved substances. This further demonstrates that the fiber powder from Brands A and B performs well after application, and the boiler water quality meets the standard requirements.

[0090] It should be noted that the fiber powder of brand A, brand B, and brand C listed in this embodiment are intended to illustrate that the evaluation method disclosed herein can be used to assess the impurity ions dissolved in different fiber powders. No specific brand is given or limited, and the fiber powder can be from any manufacturer. The evaluation method of this embodiment can evaluate the impurity ion leaching of fiber powder from different manufacturers, determine the level of leaching in the fiber powder, and thus judge the quality of the fiber powder.

[0091] This disclosure proposes a method for evaluating the level of impurity ion leaching in inert fiber powder, which has the following advantages over the prior art: This disclosure proposes a comprehensive, rapid and applicable method for evaluating the impurity ion leaching in inert fiber powder in industrial settings, which can effectively avoid the limitation of judging the quality of fiber powder as unqualified based on the exceedance of a single indicator, providing a scientific basis for water treatment in boiler systems, and ensuring the quality of boiler water and the safe operation of boilers.

[0092] 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 evaluating the level of impurity ion leachates in inert fiber powder, characterized in that, The method includes: The inert fiber powder was soaked in high-temperature, high-purity water; Ion chromatography was used to perform full-spectrum analysis of anions and cations in the soaking solution, and the mass concentrations of anions and cations were obtained respectively. Based on the mass concentrations of the anions and cations, calculate the dissolution indices of the anions and cations respectively; To determine whether the cationic dissolution index is less than the cationic dissolution index threshold and whether the anionic dissolution index is less than the anionic dissolution index threshold, the evaluation results of the level of impurity ion dissolution in inert fiber powder are obtained.

2. The method according to claim 1, characterized in that, The inert fiber powder is soaked in high-purity water at a temperature of 65-75℃ for 1.5-3 hours.

3. The method according to claim 2, characterized in that, The mass ratio of the inert fiber powder to high-purity water is 1:(45-55).

4. The method according to claim 3, characterized in that, The inert fiber powder was soaked in high-purity water at a temperature of 70℃ for 2 hours. The mass ratio of the inert fiber powder to high-purity water is 1:

50.

5. The method according to claim 1, characterized in that, The dissolution index of cations is calculated using the following formula: In the formula, CDI is the dissolution index of impurity cations in the immersion solution, n represents the number of cation types, and k i C represents the contribution of the measured cations to the conductivity of the immersion solution. i Λ represents the mass concentration of the cations measured in the soaking solution. m M is the limiting molar conductivity of the cation to be measured. i denoted as α, where α is the molar mass of the cation.

6. The method according to claim 5, characterized in that, The impurity cations in the inert fiber powder include Na. + K + Mg 2+ Ca 2+ .

7. The method according to claim 1, characterized in that, The dissolution index of anions is calculated using the following formula: In the formula, ADI is the dissolution index of impurity anions in the soaking solution, n represents the number of anion types, and k j C represents the contribution of the measured anions to the conductivity of the immersion solution. j Λ represents the mass concentration of the anion measured in the soaking solution. m M is the limiting molar conductivity of the anion to be measured. j denoted as , where is the molar mass of the anion.

8. The method according to claim 7, characterized in that, The impurity anions in the inert fiber powder include Cl. - SO4 2- NO3 - .

9. The method according to claim 1, characterized in that, The cationic dissolution index threshold is 6 μS / cm; The anion dissolution index threshold is 2 μS / cm.

10. The method according to claim 1, characterized in that, Before using ion chromatography to determine the anions in the soaking solution, the method further includes: The soaking solution was filtered using a 0.4-0.5μm filter membrane.

Images