Method for measuring hardness of raw water of power plant and data processing method

Abstract

The invention discloses a method for measuring the hardness of raw water of a power plant and processing data by using wavelength dispersive X-ray fluorescence spectrometry, which comprises the following steps of: adding a curing agent into a certain amount of raw water sample to cure the raw water sample, measuring the spectral intensity of the raw water sample by using a wavelength dispersive X-ray fluorescence spectrophotometer, and then obtaining the content of calcium and magnesium in the raw water according to a standard working curve. And the data is converted into several expression forms with common hardness through a data processing system. The method provided by the invention has the advantages of good repeatability and reproducibility, high precision and accuracy, simplicity, convenience and rapidness, can be used for batch determination, and saves manpower and material resource costs.

Description

Technical Field

[0001] The invention belongs to the technical field of raw water hardness testing, and in particular relates to a method for measuring the hardness of raw water in a power plant and a data processing method. Background Art

[0002] Since the power plant needs to conduct a comprehensive assessment of the water quality of the source water during the design phase, including items such as raw water hardness, the accurate determination of the raw water hardness of the power plant is of great significance to the chemical design of the power plant. In addition, after the generator set is put into operation, the quality of the raw water also needs to be regularly monitored. At present, the hardness in the raw water of the power plant is determined by EDTA titration. EDTA titration is a commonly used chemical analysis method, which is mainly used to determine the content of calcium and magnesium ions in water samples to determine the hardness of water. This method is based on the principle that ethylenediaminetetraacetic acid (EDTA) forms a stable complex with calcium and magnesium ions. By accurately titrating the EDTA standard solution, the content of the hardness component in the water sample is calculated according to the reaction molar ratio relationship. Although the EDTA titration method is widely used in water quality monitoring, environmental science and industrial production due to its simple operation and high accuracy, it still has some shortcomings in the determination of hardness in raw water of power plants. The experimental operation procedure is complicated, the method involves multiple dosing and color change reactions, and there are many steps. The test time of a single sample is as long as 30 minutes, which causes serious waste of personnel and large analysis errors.

[0003] In recent years, X-ray fluorescence spectroscopy has achieved rapid development in many fields with its high efficiency, non-destructiveness and ability to analyze multiple elements simultaneously. However, despite its broad application prospects, X-ray fluorescence spectrometers still face many challenges in directly measuring liquid samples. When using X-ray fluorescence to directly measure liquid samples, a significant problem is the fragility of the film. Commonly used Mylar film or Prolene film is easily damaged under long-term or high-intensity X-ray irradiation. Once damaged, the liquid may leak into the beryllium window, which will not only contaminate the inside of the instrument, but may also directly cause damage to the XRF (X-ray fluorescence spectrometer). In addition, the physical properties of the liquid also bring difficulties to the measurement. Due to the existence of surface tension, liquid samples are prone to uneven liquid surface and fluctuations during the test process. These phenomena will directly affect the penetration of X-rays and the reception of fluorescence signals, thereby reducing the accuracy of the test. At the same time, liquid samples are easy to volatilize during the test process. Once the volatilized gas enters the inside of the instrument, it will also damage the instrument and even affect its normal operation. There are various definitions of raw water hardness in power plants internationally. Different definitions such as German degrees, British degrees, American degrees, and equivalent concentrations inevitably lead to ambiguity in data exchange and comparison. This inconsistency in definition not only increases the complexity of data processing, but may also lead to wrong decisions due to misunderstandings. Therefore, although X-ray fluorescence spectroscopy has great potential in measuring liquid samples, many technical difficulties and inconsistencies in definitions still need to be overcome in practical applications. Future research should focus on developing more stable film materials, optimizing testing methods for liquid samples, and promoting international standardization of water hardness definitions to promote the application and development of X-ray fluorescence spectroscopy in more fields. Summary of the invention

[0004] The purpose of the present invention is to provide a method for determining the hardness of raw water in a power plant and a data processing method, so as to solve the technical problems of low efficiency and long time consumption of EDTA titration method.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention discloses a method for measuring the hardness of raw water in a power plant, comprising the following steps: S1: X-ray fluorescence spectrometry is used to determine the concentration and spectral intensity of calcium and magnesium in a series of standard samples, and a working curve is drawn using the concentration and spectral intensity; S2: preparing a mixed standard solution of calcium ions and magnesium ions; then adding agar powder and gum arabic to the mixed standard solution of calcium ions and magnesium ions and heating them in a water bath to obtain a mixed working solution; S3: pouring the mixed working solution into the raw water to be tested for solidification, and after solidification, using X-ray fluorescence spectrometry to determine the calcium and magnesium content in the raw water to be tested after solidification according to the working curve to obtain measurement data.

[0006] Furthermore, the method for preparing a mixed standard solution of calcium ions and magnesium ions is: After mixing the calcium standard solution and the magnesium standard solution, prepare the calcium ion and magnesium ion standard stock solutions by diluting the volume with reagent water; The calcium ion and magnesium ion standard stock solutions are diluted with reagent water to prepare a mixed standard solution of calcium ions and magnesium ions.

[0007] Furthermore, the concentration of the calcium standard solution is 1-100 mg / L; the concentration of the magnesium standard stock solution is 1-100 mg / L.

[0008] Furthermore, the dosage ratio of the mixed standard solution of agar powder, gum arabic, calcium ions and magnesium ions is 0.15g:0.1g:7.00mL.

[0009] Furthermore, the water bath heating temperature is 80-85° C., and the heating time is 20-25 min.

[0010] Furthermore, the curing time is 20 to 25 minutes.

[0011] Furthermore, the process of drawing the working curve is the same as the method S2~S3 for measuring the calcium and magnesium content in the raw water to be tested, the difference being that the mixed solution is poured into the XRF liquid.

[0012] The present invention also discloses a processing method for measuring the hardness of raw water in a power plant, wherein the measurement data obtained by the above-mentioned method for measuring the hardness of raw water in a power plant is converted into different metric representations, comprising the following steps: Customize hardness calculation functions in different representations in Python, and call custom functions to convert measured data into representations of different metrics.

[0013] Further, the different metrics include equivalent concentration, German degree, British degree, American degree or French degree.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a method for determining the hardness of raw water in a power plant. The hardness data is determined by solidifying the raw water to be tested and then adopting X-ray fluorescence spectrometry. The method is simple and fast, greatly saving time and labor costs. At the same time, it avoids the influence of uneven liquid surface on the test results and improves the measurement accuracy.

[0015] Furthermore, this method can avoid the influence of liquid surface tension on the test results during direct testing by solidifying the sample, and this method can effectively avoid the volatilization of the liquid and the damage to the instrument caused by the rupture of the Mylar film or Prolene film by converting the sample from liquid to solid for measurement. In addition, this method can quickly convert the test results into various forms of representation, which is convenient for the interpretation of the data.

[0016] The present invention also discloses a method for processing the above-mentioned measurement data, innovatively applies the xlwings module to the X-ray fluorescence spectrometry data processing, and customizes the data processing function. The method is simple and convenient, and the test data can be processed in batches to obtain hardness values ​​expressed in various forms, thereby solving the problem of data ambiguity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of the method for measuring the hardness of raw water in a power plant and data processing according to the present invention; Figure 2 This is the standard working curve for measuring the hardness of raw water in a power plant according to the present invention. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0019] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0020] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0021] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0022] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0023] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0024] like Figure 1 As shown, the present invention discloses a method for measuring the hardness of raw water in a power plant, comprising the following steps: Step 1: Use a pipette to transfer a certain volume of calcium standard solution and magnesium standard solution of a certain concentration, add them to a series of volumetric flasks of a certain capacity, and use reagent water to make up to the mark to prepare calcium ion and magnesium ion standard stock solutions of a certain concentration respectively: Step 2: Use a pipette to take a certain volume of the above calcium ion standard stock solution and magnesium ion standard stock solution and add them to a series of volumetric flasks of a certain capacity, and use reagent water to make up to the mark to obtain a mixed standard solution of calcium ion and magnesium ion: Step 3: Use a pipette to take a series of mixed standard solutions of calcium ions and magnesium ions in different volumes from small to large, add them into N volumetric flasks of a certain capacity, and use reagent water to make up to the mark to obtain N groups of mixed standard working solutions of different concentrations: Step 4: Weigh a certain amount of agar and gum arabic mixture in a certain proportion and add them into a series of colorimetric tubes of a certain capacity: Step 5: Weigh a certain amount of standard series solution into the series of colorimetric tubes with agar powder and gum arabic mixture added above, cover tightly, and shake well: Step 6: Place the above series of colorimetric tubes in a water bath that has been preheated to a certain temperature and heat for a certain period of time: Step 7: Pour the solution in the beaker into the XRF liquid cup while it is still hot, cover it with a lid, and let it stand for a certain period of time to solidify; Step 8: Adjust the X-ray fluorescence spectrometer to the optimal conditions for testing calcium and magnesium elements; Step 9: Establish a liquid sample analysis method, measure the standard samples prepared in step 7 in sequence, and draw a working curve; Step 10: Prepare the raw water to be tested according to the sample preparation methods of steps 4 to 7, and then directly measure it on the X-ray fluorescence spectrometer. Multiple samples can be measured at one time, and the test time is only 3 minutes. After the test is completed, the data will be exported to an Excel table; Step 11: Call the xlwings module in Python to read the test data in Excel; Step 12: Customize hardness calculation functions in different representations, and call custom functions to convert the above calculation results into equivalent concentration, German degree, British degree, American degree, French degree, etc.; Step 13: Call the xlwings module to write the above calculation results into Excel.

[0025] The above method for determining the hardness of raw water in power plants has many advantages over traditional methods (such as EDTA titration), which are mainly reflected in the following aspects: Through precise pipetting and volume determination steps, a series of concentrations of calcium ion and magnesium ion mixed standard working solutions can be prepared in a standardized manner, reducing the errors caused by human operation. Using X-ray fluorescence spectrometer for determination, multiple samples can be measured at one time, and the test time is only 3 minutes, which greatly improves the measurement efficiency. At the same time, data export and subsequent processing are also automated, reducing tedious manual operations. X-ray fluorescence spectrometer has high sensitivity and can accurately determine trace elements, which improves the accuracy of measurement. Due to the standardization of sample preparation methods and measurement conditions, the measurement results have good reproducibility, which is conducive to reliable comparison and analysis of data; X-ray fluorescence spectrometer can not only determine calcium and magnesium elements, but also determine many other elements at the same time, meeting the analysis needs of multiple elements in the raw water of power plants; this method is suitable for water quality analysis of different hardness, and is not interfered by other components in the water sample, which improves the applicability of the analysis.

[0026] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0027] The sources of the instruments and materials used in the following examples are as follows: X-ray fluorescence spectrometer: German Bruker S8 Tiger wavelength dispersive X-ray fluorescence spectrometer.

[0028] Electronic balance: Swiss METTLER TOLEDO XPR204 / A electronic balance.

[0029] Water bath: Shanghai Lichen Bangxi Instrument HH-6 digital display constant temperature water bath.

[0030] Volumetric flasks: 100 mL, 1000 mL.

[0031] Colorimetric tube: 50 mL.

[0032] Beaker: 100 mL The reagent water involved in the present invention should meet the requirements of GB / T 6682-2008 for first-level reagent water.

[0033] Example 1 A method for measuring the hardness of raw water in a power plant comprises the following steps: Step 1: Magnesium ion standard stock solution (Mg 2+ Preparation of magnesium oxide (2000 mg / L): After magnesium oxide is burned at 800 °C to constant weight, accurately weigh 3.314 g into a 100 mL beaker, moisten with reagent water, drop hydrochloric acid until dissolved, then add 2.5 mL of hydrochloric acid, quantitatively transfer to a 1000 mL volumetric flask, dilute to the mark with reagent water, and store in a reagent bottle at 4 °C. Step 2: Calcium ion standard stock solution (Ca 2+ Preparation of calcium carbonate (calcium carbonate, 2000 mg / L): Dry calcium carbonate at 105±5℃ to constant weight, accurately weigh 4.994 g into a 100 mL beaker, moisten with reagent water, drop hydrochloric acid until dissolved, then add 2.5 mL of hydrochloric acid, quantitatively transfer to a 1000 mL volumetric flask, dilute to the mark with reagent water, and store in a reagent bottle at 4℃. Step 3: Use a pipette to transfer 20 mL of the calcium standard stock solution and magnesium standard stock solution prepared in step 2 into a 100 mL volumetric flask, and dilute to the mark with reagent water to prepare 400 mg / L calcium ion and magnesium ion standard stock solutions respectively; Step 4: Use a pipette to take 25 mL of the above calcium ion standard stock solution and magnesium ion standard stock solution and add them to a 100 mL volumetric flask. Use reagent water to make up to the mark to obtain a mixed standard solution of calcium ion and magnesium ion with a concentration of 200 mg / L. Step 5: Use a pipette to take 0.0, 0.5, 1.0, 2.0, 4.0, 5.0, 6.0, 8.0, and 10.0 mL of the mixed standard solution of calcium ion and magnesium ion from small to large, add them to 9 100 mL volumetric flasks, and dilute to the mark with reagent water to obtain 9 sets of mixed standard working solutions of different concentrations, as shown in Table 1 below; Table 1 Standard series mass concentration

[0034] Step 6: Weigh 0.15 g agar and 0.10 g gum arabic into a series of 50 mL colorimetric tubes; Step 7: Weigh 7.0 g (accurate to 0.001 g) of the standard series solutions in Table 1 into the series of colorimetric tubes with agar powder and gum arabic, shake well, and cover tightly; Step 8: Place the above series of colorimetric tubes in a preheated 80 ℃ water bath and heat for 20 min; Step 9: Pour the solution in the colorimetric tube into the XRF liquid cup while it is still hot, cover it with a lid, and let it stand for a certain period of time to form a stable colloid; Step 10: Adjust the X-ray fluorescence spectrometer to the optimal conditions for testing calcium and magnesium elements; the analysis parameters of the X-ray fluorescence spectrometer corresponding to the calcium and magnesium content are shown in Table 2 below; Table 2 Analysis parameters of X-ray fluorescence spectrometer

[0035] Step 11: Establish a liquid sample analysis method, measure the standard substance prepared in step 9, and draw a working curve, such as Figure 2 As shown. Figure 2 It can be seen that the standard working curves of calcium and magnesium elements R 2 They are all greater than 0.995, indicating that the spectral intensity has a good linear relationship with the concentration and can meet the test requirements.

[0036] Step 12: Solidify the raw water to be tested according to the sample preparation method of step 6 to step 9, add it to the sample cup, and measure it directly on the X-ray fluorescence instrument. Multiple samples can be measured at one time, and the test time is only 3 minutes. After the test is completed, the data will be exported to Excel.

[0037] Process the above measured data: Step 13: Call the xlwings module in Python to read the test data in the above Excel; Step 14: Call the custom function to convert the above calculation results into equivalent concentration, German degree, British degree, American degree and French degree; Step 15: Call the xlwings module to write the above calculation results into Excel, as shown in Table 3. As can be seen from the table, the samples with sample numbers 241201 to 241205 were tested in batches, and the water hardness in the form of American degrees, French degrees and British degrees was obtained through data conversion. This method is convenient, fast, simple and efficient.

[0038] Table 3 Final results of data processing

[0039] Example 2 The liquid curing test includes the following steps: Step 1: First, weigh 7.0 g of a liquid sample and place it in 6 different colorimetric tubes.

[0040] Step 2: Add 0, 0.05, 0.10, 0.15, 0.20, and 0.25 g of agar powder to the 6 colorimetric tubes in step 1 respectively.

[0041] Step 3: Add 0.25, 0.20, 0.15, 0.10, 0.05, and 0 g of gum arabic to the colorimetric tubes in step 2, respectively.

[0042] Step 4: Place the above series of colorimetric tubes in a preheated 80 ℃ water bath and heat for 20 min.

[0043] Step 5: Pour the solution in the colorimetric tube into the XRF liquid cup while it is hot, and observe its solidification after cooling for 20 minutes, as shown in Table 4. As shown in Table 4, adding 0.15g agar powder and 0.10g gum arabic to 7.0g liquid is the best ratio to convert the sample to be tested from liquid to solid.

[0044] Table 4 Liquid solidification

[0045] Example 3 Determination of liquid curing temperature and time: Step 1: First, weigh 7.0 g of a liquid sample and place it in 6 different colorimetric tubes.

[0046] Step 2: Add 0.15 g agar powder to each of the 6 colorimetric tubes in step 1.

[0047] Step 3: Add 0.10 g of gum arabic to each colorimetric tube in step 2.

[0048] Step 4: Set the temperature of different water baths to 40℃, 50℃, 60℃, 70℃, 80℃, and 90℃. After the temperature is constant, place the colorimetric tube in the water bath and heat it for 20 minutes. It was found that agar powder and gum arabic were not completely dissolved in the water baths at 40℃, 50℃, 60℃, and 70℃, while agar powder and gum arabic were completely dissolved in the water bath at 90℃. However, it was observed that the amount of liquid in the water bath was significantly reduced due to the high temperature. Therefore, 80℃ was determined to be the optimal water bath temperature.

[0049] Step 5: Pour the liquid sample in the 80°C water bath in step 4 into the XRF liquid cup and start recording the time, recording its status every 4 minutes, as shown in Table 5. From the results in Table 5, it can be seen that 20 minutes is the best cooling and solidification time.

[0050] Table 5 Liquid solidification

[0051] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for determining the hardness of raw water in a power plant, characterized in that: The following steps are involved: S1: X-ray fluorescence spectrometry is used to determine the concentration and spectral intensity of calcium and magnesium in a series of standard samples, and a working curve is drawn using the concentration and spectral intensity; S2: preparing a mixed standard solution of calcium ions and magnesium ions; then adding agar powder and gum arabic to the mixed standard solution of calcium ions and magnesium ions and heating them in a water bath to obtain a mixed working solution; S3: pouring the mixed working solution into the raw water to be tested for solidification, and after solidification, using X-ray fluorescence spectrometry to determine the calcium and magnesium content in the raw water to be tested after solidification according to the working curve to obtain measurement data.

2. A method for measuring the hardness of raw water in a power plant according to claim 1, characterized in that: The method for preparing a mixed standard solution of calcium ions and magnesium ions is: After mixing the calcium standard solution and the magnesium standard solution, prepare the calcium ion and magnesium ion standard stock solutions by diluting the volume with reagent water; The calcium ion and magnesium ion standard stock solutions are diluted with reagent water to prepare a mixed standard solution of calcium ions and magnesium ions.

3. A method for measuring the hardness of raw water in a power plant according to claim 2, characterized in that: The concentration of the calcium standard solution is 1-100 mg / L; the concentration of the magnesium standard stock solution is 1-100 mg / L.

4. A method for measuring the hardness of raw water in a power plant according to claim 2, characterized in that: The concentration of the mixed standard solution of calcium ions and magnesium ions is 1-100 mg / L.

5. A method for measuring the hardness of raw water in a power plant according to claim 1, characterized in that: The dosage ratio of the mixed standard solution of agar powder, gum arabic, calcium ions and magnesium ions is 0.15g:0.1g:7.00mL.

6. A method for measuring the hardness of raw water in a power plant according to claim 1, characterized in that: The water bath heating temperature is 80-85° C., and the heating time is 20-25 min.

7. A method for measuring the hardness of raw water in a power plant according to claim 1, characterized in that: The curing time is 20 to 25 minutes.

8. A method for measuring the hardness of raw water in a power plant according to claim 1, characterized in that: The process of drawing the working curve is the same as the method S2~S3 for measuring the calcium and magnesium content in the raw water to be tested, the difference being that the mixed solution is poured into the XRF liquid.

9. A method for processing measurement data of raw water hardness in a power plant, characterized in that: The measurement data obtained by the method for determining the hardness of raw water in a power plant according to any one of claims 1 to 8 is converted into a representation form of different metrics, comprising the following steps: Customize hardness calculation functions in different representations in Python, and call custom functions to convert measured data into representations of different metrics.

10. A method for processing measurement data of raw water hardness of a power plant according to claim 9, characterized in that: The different scales include equivalent concentration, German degree, British degree, American degree or French degree.

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