A hardness determination method suitable for water quality hardness on-line analyzer

Abstract

The application discloses a hardness determination method suitable for a water quality hardness on-line analyzer, which comprises the following steps: a. presetting a basic environment temperature t0, and a first temperature threshold t1 and a second temperature threshold t2 of the environment temperature, t1>t2; b. obtaining a hardness measurement value C1 of water quality hardness detection of the water quality hardness on-line analyzer at a current environment temperature t; c. calculating a temperature compensation value according to the difference between the current environment temperature t and the basic environment temperature t0; d. judging the relationship between the current environment temperature t and the first temperature threshold t1 and the second temperature threshold t2, when t>t1, subtracting the temperature compensation value from the hardness measurement value C1 to obtain a final water quality hardness value C2, and when t<=t2, adding the temperature compensation value to the hardness measurement value C1 to obtain the final water quality hardness value C2. The hardness determination method reduces the deviation between the hardness measurement value and the true value by temperature compensation of the hardness measurement value, and improves the accuracy, reliability and authenticity of the determination result.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water quality analysis, in particular to a hardness determination method suitable for a water quality hardness online analyzer. BACKGROUND

[0002] The water quality hardness online analyzer is an instrument for monitoring and measuring the hardness parameter in the water body. Hardness refers to the concentration of calcium ions and magnesium ions in water, which is the total amount of dissolved calcium and magnesium salts in water. The purpose of measuring water hardness is to understand whether there are too many hardness salts in the water body so as to take appropriate measures. In the process of circulating cooling water, the determination of hardness is of great significance. The monitoring of hardness index can prevent the formation of water scale in the boiler, which affects heat conduction and may even cause explosion. Therefore, the accuracy of water quality hardness detection is crucial to the process of circulating cooling water. However, the existing water quality hardness online analyzer has a large deviation between the measured value and the true value in the process of circulating cooling water, which affects the running efficiency and safety of the process of circulating cooling water. SUMMARY

[0003] In view of the above problems, the present application aims to provide a hardness determination method suitable for a water quality hardness online analyzer to improve the accuracy of hardness detection of the water quality hardness online analyzer.

[0004] To achieve the above-mentioned purpose, the technical solution provided by the present application is as follows:

[0005] A hardness determination method suitable for a water quality hardness online analyzer, comprising the following processes:

[0006] a. Pre-set the basic ambient temperature t0, and the first temperature threshold t1 and the second temperature threshold t2 of the ambient temperature, t1>t2;

[0007] b. Obtain the hardness measurement value C1 of the water quality hardness online analyzer for hardness detection of the water quality at the current ambient temperature t;

[0008] c. Calculate the temperature compensation value according to the difference between the current ambient temperature t and the basic ambient temperature t0;

[0009] d. Determine the relationship between the current ambient temperature t and the first temperature threshold t1 and the second temperature threshold t2,

[0010] When t>t1, the hardness measurement value C1 is subtracted by the temperature compensation value to obtain the final water quality hardness value C2,

[0011] When t≤t2, the hardness measurement value C1 is added by the temperature compensation value to obtain the final water quality hardness value C2.

[0012] Preferably, in process d, when t2 < t < t1, the hardness measurement value C1 is directly taken as the final water quality hardness value C2,

[0013] Alternatively, in process d, when t2 < t < t1, a coefficient k0 is set, wherein the coefficient k0 < 0.5, a deviation value is calculated by multiplying the coefficient k0 and the temperature compensation value, the hardness measurement value C1 is added with the deviation value to obtain the final water quality hardness value C2.

[0014] Preferably, the coefficient k0 = 0.25.

[0015] Preferably, the calculation formula of the temperature compensation value is as follows:

[0016] ΔC = k × (t - t0) × C1; k is a temperature compensation coefficient.

[0017] Preferably, the basic environmental temperature t0 = 25-27℃.

[0018] Preferably, the first temperature threshold t1 = 25℃, and the second temperature threshold t2 = 5℃.

[0019] Preferably, the temperature compensation coefficient k is a linear fitting formula between the average temperature compensation coefficient and the average hardness measurement value .

[0020] Preferably, the average temperature compensation coefficient is the slope of a linear regression formula of the hardness deviation rate m corresponding to different environmental temperatures t of the same standard solution and the environmental temperature t.

[0021] Alternatively, the average temperature compensation coefficient is the average value of the ratio of the hardness deviation rate m corresponding to different environmental temperatures t of the same standard solution and the temperature difference, wherein the temperature difference = t-t0.

[0022] Preferably, the calculation formula of the hardness deviation rate m is as follows:

[0023] Alternatively, the calculation formula of the hardness deviation rate m is as follows:

[0024]

[0025] Preferably, the average hardness measurement value is the average value of the hardness measurement value C1 corresponding to different environmental temperatures of the same standard solution.

[0026] Preferably, the calculation method of the temperature compensation coefficient k is as follows:

[0027] S1: Obtain standard solutions with different hardnesses;

[0028] S2: Use the aforementioned online water hardness analyzer to detect and record the hardness C of each standard solution at an ambient temperature t of 25℃. 常 ;

[0029] S3: Use the online water hardness analyzer to detect and record the hardness measurement value C1 corresponding to different ambient temperatures t for each standard solution;

[0030] S4: Based on the hardness measurement value C of the same standard solution at an ambient temperature of 25℃ 常 The temperature compensation coefficient for each standard solution at different ambient temperatures t was calculated based on the hardness measurement value C1 at different ambient temperatures t.

[0031]

[0032] S5: Take the average value of the calculated temperature compensation coefficients corresponding to different ambient temperatures t for the same standard solution to obtain the average temperature compensation coefficient. The average hardness measurement value C1 corresponding to different ambient temperatures t of the same standard solution is obtained by averaging the measured values.

[0033] S6: Average temperature compensation coefficient for standard solutions with different hardness With the corresponding average hardness measurement value Perform linear regression and use the equation obtained from the linear regression as the formula for calculating the temperature compensation coefficient k.

[0034] Preferably, k = 0.0285 - 0.0022 × C1.

[0035] By adopting the above technical solution, the beneficial effects of the present invention are as follows: the present invention reduces the deviation between the hardness measurement value and the true value by performing temperature compensation on the hardness measurement value, and the data is relatively accurate, reliable and true. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments.

[0037] Example 1

[0038] The high internal water temperature and ambient temperature of the circulating cooling water process can affect the hardness test results, leading to inaccurate results and significant deviations between the measured hardness values ​​and the actual water hardness, thus impacting the judgment and assessment of water quality. Therefore, this invention provides a hardness measurement method suitable for online water hardness analyzers, comprising the following steps:

[0039] a. Pre-set the base ambient temperature t0, and the first temperature threshold t1 and the second temperature threshold t2 of the ambient temperature, where t1 > t2.

[0040] b. Obtain the hardness measurement value C1 of the water quality hardness detection by the water quality hardness online analyzer at the current environment temperature t.

[0041] c. Calculate the temperature compensation value according to the difference between the current environment temperature t and the basic environment temperature t0.

[0042] d. Determine the relationship between the current environment temperature t and the first temperature threshold t1 and the second temperature threshold t2:

[0043] When t>t1, subtract the temperature compensation value from the hardness measurement value C1 to obtain the final water quality hardness value C2.

[0044] When t≤t2, add the temperature compensation value to the hardness measurement value C1 to obtain the final water quality hardness value C2.

[0045] In process d, when t2

[0046] The basic environment temperature t0 of the embodiment is 25-27℃, and preferably t0=27℃. The first temperature threshold t1 is 25℃, and the second temperature threshold t2 is 5℃.

[0047] The calculation formula of the temperature compensation value of the embodiment is as follows:

[0048] ΔC=k×(t-t0)×C1;

[0049] Wherein, k is the temperature compensation coefficient.

[0050] The temperature compensation coefficient k of the embodiment is a linear fitting formula between the average hardness measurement value and the average temperature compensation coefficient .

[0051] Wherein, the average hardness measurement value is the average value of the hardness measurement value C1 corresponding to different environment temperatures t of the same standard solution. The average temperature compensation coefficient is the average value of the ratio of the hardness deviation rate m to the temperature difference (t-t0) corresponding to different environment temperatures t of the same standard solution. The calculation formula of the hardness deviation rate m of the embodiment has two kinds: and the other is selected.

[0052] The specific calculation method of the temperature compensation coefficient k of the embodiment is as follows:

[0053] S1: Obtain standard solutions with different hardness.

[0054] S2: Use an online hardness analyzer to detect and record the hardness values ​​C of each standard solution at an ambient temperature t = 25℃. 常 ;

[0055] S3: Use an online hardness analyzer to detect and record the hardness measurement value C1 corresponding to different ambient temperatures t for each standard solution, where 0℃≤t≤40℃.

[0056] S4: Based on the hardness measurement value C of the same standard solution at an ambient temperature t of 25℃ 常 The temperature compensation coefficient for each standard solution under different ambient temperature conditions t is calculated based on the hardness measurement value C1 corresponding to different ambient temperatures t, using the following formula:

[0057]

[0058] S5: Take the average value of the calculated temperature compensation coefficients corresponding to different ambient temperatures t for the same standard solution to obtain the average temperature compensation coefficient. The average hardness measurement value C1 corresponding to different ambient temperatures t of the same standard solution is obtained by averaging the measured values.

[0059] S6: Average temperature compensation coefficient for standard solutions with different hardness With the corresponding average hardness measurement value Perform linear regression and use the equation obtained from the linear regression as the formula for calculating the temperature compensation coefficient k, as follows:

[0060] k = 0.0285 - 0.0022 × C1.

[0061] The difference of hardness measurement value in the experimental data at 25-27℃ is not large, the final error is minimum when t-27 is calculated and compared, therefore, the compensation percentage is set as the percentage of compensation required relative to 27℃, the final water quality hardness value C2=C1-(0.0285-0.0022xC1)x(t-27)xC1. The formula is that the hardness measurement value increases with the increase of temperature when the temperature starts to rise from the normal temperature 25℃. According to the measurement data table, below 25℃, the proportion of the difference of hardness measurement value is opposite, the hardness measurement value decreases with the increase of temperature, therefore, the compensation percentage should be negative, i.e. -kx(t-27), the final water quality hardness value C2=C1+(0.0285-0.0022xC1)x(t-27)xC1. The overall percentage of hardness measurement value change at low temperature is smaller than that at high temperature, the final low temperature compensation formula needs to multiply a coefficient 0.25, i.e. C2=C1-0.25x(0.0285-0.0022xC1)x(t-27)xC1. When the environmental temperature is tested to 5℃, the change value of hardness measurement value starts to mutate and increase more, the percentage obtained by using the low temperature compensation formula is not enough, therefore, according to the actual change, it is obtained that C2=C1-(0.0285-0.0022xC1)x(t-27)xC1.

[0062] In summary, the calculation formula of the final water quality hardness value C2 is as follows:

[0063] t>25℃, C2=C1-(0.0285-0.0022xC1)x(t-27)xC1;

[0064] 5℃

[0065] t≤5℃, C2=C1+(0.0285-0.0022xC1)x(t-27)xC1;

[0066] The above formula is brought into the test data tables 1-3, the hardness value after compensation of each group of data and the standard solution error are calculated, as shown in the following table, the final error is basically within 5%.

[0067] Test data table 1 (standard solution 2mg / L)

[0068]

[0069]

[0070] Test data table 2 (standard solution 5mg / L)

[0071]

[0072]

[0073]

[0074] Test data table 3 (standard solution 8 mg / L)

[0075]

[0076]

[0077] The embodiment of the present application can coordinate the influence of different environmental temperatures on the hardness determination results by finding the influence law of the environmental temperature on the water quality hardness on-line analyzer, temperature compensating the hardness measurement value, and obtaining the final water quality hardness value.

[0078] Embodiment two

[0079] The embodiment is similar to embodiment one, and the main difference between the two is that the average temperature compensation coefficient k of the embodiment is the slope of the linear regression formula of the hardness deviation rate m corresponding to the different environmental temperatures t of the same standard solution and the environmental temperature t.

[0080] The specific calculation method of the temperature compensation coefficient k of the embodiment is as follows:

[0081] S1: Obtain standard solutions with different hardness.

[0082] S3: Detect and record the hardness measurement value C1 corresponding to the different environmental temperatures t of each standard solution by using the water quality hardness on-line analyzer.

[0083] S4: Linearly regress the hardness measurement value C1 corresponding to the different environmental temperatures t of the same standard solution and the environmental temperature t to obtain a linear regression formula, and take the slope of the linear regression formula as the average temperature compensation coefficient k. Take the average of each hardness measurement value C1 corresponding to the different environmental temperatures t of the same standard solution to obtain the average hardness measurement value C.

[0084] S5: Linearly regress the average temperature compensation coefficient k of the standard solutions with different hardness and the corresponding average hardness measurement value C. , and take the equation obtained by linear regression as the calculation formula of the temperature compensation coefficient k.

[0085] Although the present application is specifically shown and introduced in combination with the preferred embodiments, it should be understood by those skilled in the art that various changes can be made to the present application in form and detail without departing from the spirit and scope of the present application defined by the appended claims, and all such changes are within the protection scope of the present application.

Claims

1. A method for hardness determination suitable for online water hardness analyzers, characterized in that, The process includes the following: a. Pre-set the base ambient temperature t0, and the first temperature threshold t1 and the second temperature threshold t2 of the ambient temperature, where t1 > t2; b. Obtain the hardness measurement value C1 of the water hardness test conducted by the online water hardness analyzer at the current ambient temperature t; c. Calculate the temperature compensation value based on the difference between the current ambient temperature t and the baseline ambient temperature t0; d. Determine the relationship between the current ambient temperature t and the first temperature threshold t1 and the second temperature threshold t2: When t > t1, the temperature compensation value is subtracted from the measured hardness value C1 to obtain the final water hardness value C2. When t≤t2, the temperature compensation value is added to the hardness measurement value C1 to obtain the final water hardness value C2. The formula for calculating the temperature compensation value is as follows: Wherein, k is the temperature compensation coefficient; the temperature compensation coefficient k is the average temperature compensation coefficient of standard solutions with different hardness. Compared with average hardness measurement value The formula for linear fitting between them; The average hardness measurement value This represents the average hardness measurement value C1 corresponding to different ambient temperatures of the same standard solution; The average temperature compensation coefficient The slope of the linear regression formula between the hardness deviation rate *m* at different ambient temperatures for the same standard solution and the ambient temperature; or, the average temperature compensation coefficient. This is the average ratio of the hardness deviation rate m to the temperature difference for different ambient temperatures of the same standard solution, where temperature difference = t - t0.

2. The hardness determination method applicable to online water hardness analyzers according to claim 1, characterized in that, In process d, when t2 < t ≤ t1, the measured hardness value C1 is directly used as the final water hardness value C2. or, Set a coefficient k0, where k0 < 0.

5. Calculate the deviation value by multiplying k0 by the temperature compensation value. Add the deviation value to the hardness measurement value C1 to obtain the final water hardness value C2.

3. The hardness determination method applicable to online water hardness analyzers according to claim 2, characterized in that, The coefficient k0 is 0.

25.

4. The hardness determination method applicable to an online water hardness analyzer according to any one of claims 1 to 3, characterized in that, The basic ambient temperature t0 is 25℃~27℃.

5. The hardness determination method applicable to online water hardness analyzers according to claim 4, characterized in that, The first temperature threshold t1 = 25℃, and the second temperature threshold t2 = 5℃.

6. The hardness determination method applicable to an online water hardness analyzer according to any one of claims 1 to 3, characterized in that, The formula for calculating the hardness deviation rate m is as follows: ； or, 。 7. The hardness determination method for an online water hardness analyzer according to claim 1, characterized in that, The method for calculating the temperature compensation coefficient k is as follows: S1: Obtain standard solutions with different hardness; S2: Use the aforementioned online water hardness analyzer to detect and record the hardness C of each standard solution at an ambient temperature of t=25℃. 常 ; S3: Use the online water hardness analyzer to detect and record the hardness measurement value C1 corresponding to different ambient temperatures t for each standard solution; S4: Based on the hardness measurement value C of the same standard solution at an ambient temperature of 25℃ 常 The temperature compensation coefficient for each standard solution at different ambient temperatures t was calculated based on the hardness measurement values ​​C1 at different ambient temperatures t. ； S5: Take the average value of the calculated temperature compensation coefficients corresponding to different ambient temperatures t for the same standard solution to obtain the average temperature compensation coefficient. ; The average hardness measurement value C1 corresponding to different ambient temperatures t of the same standard solution is obtained by averaging the measured values. ; S6: Average temperature compensation coefficient for standard solutions with different hardness With the corresponding average hardness measurement value Perform linear regression and use the equation obtained from the linear regression as the formula for calculating the temperature compensation coefficient k.

8. The hardness determination method for an online water hardness analyzer according to claim 7, characterized in that, 。

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