CN104101722B - Entry automatic continuous analysis device and analytical approach thereof in Industrial Boiler water quality detection - Google Patents

Abstract

The invention discloses a multi-item continuous automatic analysis device and an analysis method for industrial boiler water quality detection. The device includes a container, a potentiometric titrator host, five electrodes and four liquid adding units; Electrode, pH electrode, silver electrode, platinum electrode and calcium electrode, the four liquid addition units are standard acid solution addition unit, silver nitrate standard solution addition unit, standard potassium iodate-potassium iodide addition unit and EDTA standard solution Adding liquid unit; the five electrodes are placed in the container, and the liquid outlets of the four adding liquid units are all placed in the container. The main body of the potentiometric titrator has five electrode interfaces, and the five electrode interfaces correspond to Connect conductivity electrode, pH electrode, silver electrode, platinum electrode and calcium electrode. The potentiometric titrator host has a built-in titration parameter control and data output control system.

Description

Multi-item continuous automatic analysis device and analysis method for industrial boiler water quality detection

technical field

The invention relates to a water treatment technology, in particular to a multi-item continuous automatic analysis device and an analysis method for industrial boiler water quality detection.

Background technique

Industrial boiler water needs to maintain a certain value of alkalinity in order to slow down the corrosion and scaling of metal pipes. According to national technical standards, alkalinity is further divided into phenolphthalein alkalinity and total alkalinity. Low pH and alkalinity may cause acidic corrosion of metals in contact with water; on the contrary, high pH and alkalinity may cause alkaline corrosion of metals in contact with water. Industrial boiler water also needs to control the impurity concentration not to exceed the limit. If the impurity concentration exceeds the limit, it may also accelerate metal corrosion and cause scaling. Chloride ions are the most stable of all impurities, and the concentration of chloride ions is easy to detect, so the industry generally controls the concentration of impurities by controlling the concentration of chloride ions. Since oxygen will cause oxygen corrosion of industrial boilers, sulfite is the most commonly used oxygen scavenger, so the concentration of sulfite in industrial boiler water needs to be controlled. Excessive hardness (calcium, magnesium ions) will cause industrial boilers to scale easily, so the hardness of industrial boiler water needs to be controlled. Dissolved solids represent the content of dissolved impurities in water, and the dissolved solids content is usually calculated by the solid conductivity ratio method after measuring the electrical conductivity. The larger the dissolved solids, the greater the impurity content in the water, and vice versa, the smaller the impurity content, so industrial boilers use water to detect dissolved solids.

Therefore, in order to slow down metal corrosion and reduce scaling, GB/T1576 "Industrial Boiler Water Quality" includes dissolved solids, pH value, phenolphthalein alkalinity, total alkalinity, chloride ion concentration, hardness, sulfite concentration and other items. Routine monitoring items.

Most of the existing industrial boiler water quality detection technologies are analyzed by manual detection or single-item potentiometric titration. It takes more than an hour to finish testing the seven items.

Potentiometric titration is a method of determining the titration end point by measuring the potential change during the titration process. Compared with the direct potentiometric method, the potentiometric titration method does not need to accurately measure the electrode potential value. The potentiometric titration method relies on the sudden jump of the electrode potential to indicate the titration. end.

The existing detection process of dissolved solids, pH value, phenolphthalein alkalinity, total alkalinity, chloride ion, hardness, and sulfite is carried out separately, and the detection process is as follows:

1. Determination of dissolved solids (solid conductance ratio method)

After collecting a certain volume of sample to be tested, put the conductivity electrode into the sample, the conductivity of the sample will transmit the potential signal to the host, and the host will convert the potential signal to display the conductivity value of the sample. According to the solid conductivity ratio, the content of dissolved solids was calculated.

2. pH measurement

After collecting a certain volume of sample to be tested, put the pH electrode into the sample, the pH value of the sample will transmit the potential signal to the host, and the host will convert the potential signal to display the pH value of the sample.

3. Determination of phenolphthalein alkalinity and total alkalinity

After collecting a certain volume of sample to be tested, put the pH electrode into the sample, add sulfuric acid standard solution dropwise to the sample until the pH drops to a certain limit, and calculate the base by the volume of the sample to be tested, the consumption volume and concentration of the standard acid solution degree value. Limits set at pH 8.0-8.3 result in phenolphthalein alkalinity and limits set at pH 4.0-4.3 result in total alkalinity.

4. Determination of chloride ion

After collecting a certain volume of sample to be tested, adjust the pH value of the sample to neutral or acidic, add dropwise silver nitrate standard solution to the solution for potentiometric titration of chloride ions, until a sudden jump point appears, and the titration is terminated. Calculate the chloride ion concentration value based on the volume of the sample to be tested, the consumption volume of the silver nitrate standard solution and its concentration.

5. Hardness measurement

After collecting a certain volume of the sample to be tested, adjust the pH value of the sample to 10.0±0.1, use chrome black T as the indicator, add disodium ethylenediaminetetraacetic acid (EDTA) standard solution dropwise into the solution until the solution turns blue as the end point . The hardness value is calculated based on the volume of the sample to be tested, the consumed volume of the EDTA standard solution and its concentration.

6. Determination of sulfite

After collecting a certain volume of sample to be tested, add 1mL starch indicator and 1mL hydrochloric acid solution (1+1), and shake well. Titrate with potassium iodate-potassium iodide standard solution until slightly blue, which is the titration end point. The concentration of sulfite was calculated based on the volume of the sample to be tested, the consumption volume of potassium iodate-potassium iodide standard solution and its concentration.

Most of the existing industrial boiler water quality detection technologies are based on national standard methods, and the seven items are respectively in accordance with GB/T6904-2008 "Determination of pH Value in Industrial Circulating Cooling Water and Boiler Water" and GB/T1576-2008 "Industrial Boiler Water Quality" Appendix H Determination of Alkalinity, GB/T1576-2008 "Industrial Boiler Water Quality" Appendix E Indirect Determination of Dissolved Solids in Boiler Water, GB/T1576-2008 "Industrial Boiler Water Quality" Appendix I Sulfite Determination (Iodometric Method) , GB/T6909-2009 "Determination of hardness of boiler water and cooling water analysis method", GB/T15453-2008 "Determination of chloride ions in industrial circulating cooling water and boiler water" independent detection. It takes more than an hour for skilled inspectors to complete seven items alone, which not only has low detection efficiency but also has many limitations. For example, it is affected by the sensitivity of the indicator and color change, the precipitation and adsorption, the strict pH titration environment and the interference of various anions and cations, and the human factors of manual titration by analysts, etc.

Contents of the invention

One of the technical problems to be solved by the patent of the present invention is that for the above-mentioned detection of the dissolved solids, pH value, phenolphthalein alkalinity, total alkalinity, chloride ion concentration, hardness, and sulfite concentration of industrial boiler water in the prior art, , the defect of low efficiency in the existing technology, providing a multi-item continuous automatic analysis device and analysis method in industrial boiler water quality detection, the detection items include dissolved solids, pH value, phenolphthalein alkalinity, total alkalinity, chloride ion Concentration, hardness and sulfite concentration.

The technical solution adopted by the present invention to solve the technical problem is: a multi-item continuous automatic analysis device in industrial boiler water quality detection, which includes a container, a potentiometric titrator host, five electrodes and four liquid addition units; the five electrodes They are conductivity electrode, pH electrode, silver electrode, platinum electrode and calcium electrode. The four liquid addition units are standard acid liquid addition unit, silver nitrate standard liquid addition unit, standard potassium iodate-potassium iodide liquid addition unit and EDTA standard liquid dosing unit; the five electrodes are placed in the container, the liquid outlets of the four dosing units are all placed in the container, the potentiometric titrator host has five electrode interfaces, and the five electrodes The interfaces are respectively connected to conductivity electrodes, pH electrodes, silver electrodes, platinum electrodes and calcium electrodes. The potentiometric titrator host has a built-in titration parameter control and data output control system.

Further, the host of the potentiometric titrator also includes a communication interface connected with the computer, and the control system is connected with the computer through the communication interface.

Further, an electrode protection unit for accommodating and fixing the five electrodes is also included.

Further, a titration stand provided with a stirrer is also included, and the container is placed on the titration stand.

Specifically, the container is a measuring cup.

As another object of the present invention, there is also provided a multi-item continuous automatic analysis method in the water quality detection of industrial boilers, the steps of which are as follows:

a. Collect the conductivity of the sample to be measured through the conductivity electrode;

b. Turn off the conductivity electrode, turn on the pH electrode and the standard acid solution dosing unit, perform phenolphthalein alkalinity titration and total alkalinity titration on the tested sample, and collect data;

c. Close the pH electrode, open the silver electrode and the silver nitrate standard solution dosing unit, carry out the chloride ion potentiometric titration in the tested sample that has completed step b, and collect data;

d, close the silver electrode, turn on the platinum electrode, the standard acid solution addition unit and the standard potassium iodate-potassium iodide addition unit, after acidifying the tested sample that has completed step c, carry out sulfite potentiometric titration, and collect data; e 1. Turn off the platinum electrode, turn on the calcium electrode and the EDTA standard solution dosing unit, adjust the pH of the tested sample after step d to 10, and then perform hardness potentiometric titration, and collect data.

As a preferred version, the standard acid solution in the standard acid liquid addition unit is a sulfuric acid standard solution, and the concentration of the sulfuric acid standard solution is C _1/2H2SO4 =0.1000mol/L; the silver nitrate standard in the silver nitrate standard solution addition unit The titer of liquid is T=3.34mg/mL; The titer of the potassium iodate-potassium iodide standard solution in this standard potassium iodate-potassium iodide liquid addition unit is T=1.0mg/mL; The titer of the EDTA standard solution is T=0.1mol/L.

Compared with the prior art, the positive effect of the present invention is that the present invention integrates seven independent detection processes into one detection process, and after realizing a sampling, completes the conductivity (dissolved solids), pH value, phenolphthalein alkalinity, Detection of total alkalinity, chloride ion concentration, sulfite concentration and hardness. The entire testing process takes less than ten minutes. The invention is characterized in that the detection efficiency is improved, the workload of personnel is reduced, and the consumption of samples and standard products is saved at the same time.

The present invention will be further described below in conjunction with drawings and embodiments.

Description of drawings

Fig. 1 is a schematic diagram of the multi-item continuous automatic analysis device in the industrial boiler water quality detection of the present invention.

Fig. 2 is the flow chart of the analysis method for continuous analysis of dissolved solids, pH value, phenolphthalein alkalinity, total alkalinity, chloride ion concentration, sulfite concentration, and hardness of the present invention.

Fig. 3 is the phenolphthalein alkalinity titration curve of embodiment.

Fig. 4 is the total alkalinity titration curve of embodiment.

Fig. 5 is the chloride ion titration curve of embodiment.

Fig. 6 is the hardness titration curve of the embodiment.

Among them, 1-standard acid liquid addition unit; 2-silver nitrate standard liquid addition unit; 3-standard potassium iodate-potassium iodide addition liquid unit; 4-EDTA standard liquid addition unit; 5-conductivity electrode; 6-pH Electrode; 7-silver electrode; 8-calcium electrode; 9-platinum electrode.

Detailed ways

Example

As shown in Figure 1, the multi-item continuous automatic analysis device in the industrial boiler water quality detection of the present embodiment includes a container, a potentiometric titrator host, five electrodes, four liquid addition units and a titration stand; the five electrodes are respectively Conductivity electrode 5, pH electrode 6, silver electrode 7, platinum electrode 9 and calcium electrode 8, the four liquid addition units are standard acid solution addition unit 1, silver nitrate standard solution addition unit 2, standard potassium iodate- Potassium iodide liquid addition unit 3 and EDTA standard solution addition liquid unit 4.

The container is placed on a titration stand, and a stirrer is arranged on the titration stand. The five electrodes are placed in the container for collecting the data of the sample to be measured in the container. The liquid outlets of the four liquid adding units are all placed in the container, and liquid is added to the container. The main body of the potentiometric titrator has five electrode interfaces and a communication interface connected with the computer. Corresponding to the collection of conductivity data, the collection of the initial pH value of the tested sample and the real-time pH value during the titration process of phenolphthalein alkalinity and total alkalinity, the collection of the silver electrode 7 potential value of the chloride ion potentiometric titration process, and the collection of the sulfite ion potentiometric titration process 9 potentials of the platinum electrode, and 8 potentials of the calcium electrode during the hardness potentiometric titration. The host of the potentiometric titrator has a built-in control system for titration parameter control and data output. Preferably, the potentiometric titrator host model of the built-in control system is Metrohm 905 Titrando. The control system is connected to the computer through the communication interface, and the obtained phenolphthalein alkalinity titration, total alkalinity titration, chloride ion potentiometric titration, sulfite radical titration, hardness potentiometric titration data are displayed on the computer and processed, including 3. Instant display of the titration curves shown in Fig. 4, Fig. 5 and Fig. 6.

In this embodiment, preferably, the container is a measuring cup that accommodates a set volume of the measured sample.

The device also includes an electrode protection unit for accommodating and fixing the electrodes respectively after the analysis is completed. After the analysis is finished, each electrode is rinsed with distilled water and then respectively accommodated and fixed in the electrode protection unit.

As shown in Figure 2, the multi-item continuous automatic analysis method in the industrial boiler water quality detection of the present embodiment, its analysis object is industrial boiler water, analyze its dissolved solids, pH value, phenolphthalein alkalinity, total alkalinity, chloride ion concentration , sulfite concentration, hardness, the specific analysis method comprises the following steps:

a. Fix the container containing the sample to be measured with a set volume on the titration table of the potentiometric titrator, and the conductivity electrode 5 collects the conductivity of the sample to be tested.

b. Turn off the conductivity electrode 5, turn on the pH electrode 6 and the standard acid solution adding unit 1. The pH electrode 6 collects the initial pH value of the sample to be tested and the real-time pH value of the alkalinity titration process, and the alkalinity titration is carried out in sequence: phenolphthalein alkalinity titration, the titration endpoint pH is 8.0-8.3; and total alkalinity titration, the titration endpoint When the pH is 4.0-4.3, when the titration end point is reached, read the volume of the standard acid liquid phenolphthalein alkalinity titration liquid volume and the total alkalinity titration liquid volume in the standard acid liquid adding unit 1 respectively, and calculate the phenolphthalein alkalinity and total alkalinity , the initial pH value that pH electrode 6 collects is the pH value of measured sample; Standard acid solution refers to the acidic solution of known concentration, present embodiment preferably, standard acid solution is sulfuric acid standard solution, and the concentration of sulfuric acid standard solution is C _1/2H2SO4 = 0.1000mol/L. Standard acid solution can also be nitric acid standard solution.

C, close pH electrode 6 and open silver electrode 7, carry out chloride ion potentiometric titration in the tested sample that above-mentioned full alkalinity titration has finished with silver nitrate standard solution adding unit 2, silver electrode 7 gathers the silver in the chloride ion potentiometric titration process Electrode potential value of electrode 7, chloride ion potentiometric titration is dynamic titration, titration end point is the jump point of silver electrode 7 potential, read the consumption volume of silver nitrate standard solution in silver nitrate standard solution adding liquid unit 2 when titration end point, calculate chlorine ion concentration. Silver nitrate standard solution refers to the silver nitrate solution of known concentration or titer, and in the present embodiment, the titer of silver nitrate standard solution is T=3.34mg/mL.

d. Turn off the silver electrode 7, turn on the platinum electrode 9, the standard acid solution adding unit and the standard potassium iodate-potassium iodide adding unit 3. Add 20mL of standard acid solution to the tested sample whose chloride ion concentration has been detected to acidify the sample. Use standard potassium iodate-potassium iodide liquid addition unit 3 to carry out sulfite potentiometric titration in the sample after acidification, platinum electrode 9 collects the potential value of platinum electrode 9 in the process of sulfite potentiometric titration, and sulfite potentiometric titration is dynamic titration, The titration end point is the jump point of the potential of the platinum electrode 9, and the consumed volume of the potassium iodate-potassium iodide standard solution in the standard potassium iodate-potassium iodide addition unit 3 is read at the titration end point, and the sulfite concentration is calculated. Potassium iodate-potassium iodide standard solution refers to the potassium iodate-potassium iodide solution of known concentration or titer, and in the present embodiment, the titer of potassium iodate-potassium iodide standard solution is T=1.0mg/mL.

e. Turn off the platinum electrode 9, turn on the calcium electrode 8 and the EDTA standard solution adding unit 4. Add an appropriate volume of ammonia buffer solution to the tested sample whose sulfite concentration has been detected, so that the pH of the sample reaches 10. Use the EDTA standard solution adding unit 4 to carry out hardness potentiometric titration in the sample with pH=10, the calcium electrode 8 collects the calcium electrode 8 potential value during the EDTA potentiometric titration process, the hardness potentiometric titration is static titration, and the titration end point is the calcium electrode 8 potential The breakthrough point, read the consumed volume of the EDTA standard solution in the EDTA standard solution adding unit 4 at the end of the titration, and calculate the hardness. The EDTA standard solution refers to an EDTA solution with known concentration or titer. In this embodiment, the titer of the EDTA standard solution is T=0.1mol/L.

Set parameters before analysis, specifically:

Conductivity measurement parameter settings:

pH value, alkalinity titration parameter setting: set end point titration mode (SET pH) (1) start condition: collect the initial pH value of the sample to be tested; signal drift: off; waiting time: 10s; pause for 20s. (2) Phenolphthalein alkalinity titration: set the titration end point to pH=8.3; dynamic titration, control range is 2pH; maximum liquid addition rate 10mL/min; minimum liquid addition rate 25 μL/min; stop standard: drift 50 μL/min. (3) Total alkalinity titration: set the titration end point to be pH=4.2; dynamic titration, control range is 1.5pH; maximum liquid addition rate 5mL/min; minimum liquid addition rate 25; stop standard: drift 50 μ L/min; measuring point Time interval: 2.0s. The temperature is 25°C.

Chloride ion titration parameter setting: dynamic titration mode (DET U): (1) start condition: initial measurement value signal drift off, minimum waiting time 5s, maximum waiting time 10s, liquid addition rate 5mL/min; (2) titration parameters: The signal drift of the measured value is 30mV/min, the minimum waiting time is 2s, and the maximum waiting time is 20s; the density of measuring points is 4; the minimum increment is 10μL, the maximum increment is off, and the maximum adding speed is; (3) Titration end point: silver electrode potential The first jumping point.

Nitrite titration parameter setting: dynamic titration mode (DET U): (1) start conditions: initial measurement value signal drift off, minimum waiting time 5s, maximum waiting time 10s, liquid addition rate 5mL/min; (2) titration parameters : The signal drift of the measured value is 30mV/min, the minimum waiting time is 2s, the maximum waiting time is 20s; the measurement point density is 4; the minimum increment is 10μL, the maximum increment is off, and the maximum adding speed is; (3) Titration end point: platinum electrode potential the first breakthrough point.

Hardness titration parameter setting: Static titration mode (MET U): (1) Start conditions: initial measurement value signal drift off, minimum waiting time 5s, maximum waiting time 10s, liquid addition rate 5mL/min; (2) Titration parameters: accept The signal drift of the measured value is 30mV/min, the minimum waiting time is 2s, and the maximum waiting time is 20s; the measuring point density is 4; the minimum increment is 10μL, the maximum increment is off, and the maximum adding speed; A jumping off point.

The calculation formula of this embodiment is:

pH value (25°C) = the initial pH value of the sample to be measured collected by the pH electrode. (1-1)

Alkalinity of phenolphthalein, mmol/L:

Wherein, V ₁ ——the titration liquid volume (mL) of the sulfuric acid standard solution in the phenolphthalein alkalinity titration,

V _S - the set volume of the sample to be measured, that is, the sampling volume (mL),

—concentration of sulfuric acid standard solution (mol/L).

Total alkalinity, mmol/L:

Among them, V ₂ ——the titration liquid volume (mL) of sulfuric acid standard solution in the total alkalinity titration,

V _S - the set volume of the sample to be measured, that is, the sampling volume (mL),

—concentration of sulfuric acid standard solution (mol/L).

Chloride ion concentration [Cl ^- ], mg/L: $\left[{\mathrm{Cl}}^{-}\right]=\frac{T_1\×(V_3-V_{01})\×1000}{V_S}---(1-4)$

Where: V ₀₁ - reagent blank (mL),

V ₃ —consumed volume of silver nitrate standard solution (mL),

T ₁ - the titer of silver nitrate standard solution (mg/mL),

V _S - the set volume of the sample to be measured, that is, the sampling volume (mL).

Sulfite concentration [SO ₃ ^2- ], mg/L: $\left[{{\mathrm{SO}}_3}^{2-}\right]=\frac{T_2\×(V_4-V_{02})\×1000}{V_S}---(1-5)$

Where: V ₀₂ - reagent blank (mL),

V ₄ ——consumed volume (mL) of potassium iodate-potassium iodide standard solution,

T ₂ ——The titer of potassium iodate-potassium iodide standard solution (mg/mL),

V _S - the set volume of the sample to be measured, that is, the sampling volume (mL).

Hardness, mmol/L:

Where: V ₀₃ ——reagent blank (mL),

V ₅ ——consumption volume (mL) of potassium iodate-potassium iodide standard solution,

T ₃ ——The titer of potassium iodate-potassium iodide standard solution (mg/mL),

V _S - the set volume of the sample to be measured, that is, the sampling volume (mL).

Further, the detection and analysis process is: measure 80mL of uniformly mixed tested sample in the measuring cup, and the concentration of sulfuric acid standard solution is Silver nitrate standard solution titer is T=3.34mg/mL, and the reagent blank V ₀ of silver nitrate=0.010mL, sulfuric acid standard solution, silver nitrate standard solution, potassium iodate-potassium iodide standard solution, EDTA standard solution are added respectively different The dosing unit, conductivity electrode, pH electrode, silver electrode, platinum electrode, and calcium electrode are installed on the titration table, and there is a stirrer on the titration table to start titration. Adopt 2 parallel determinations in the present embodiment, the data of 2 parallel titrations are shown in Table 1:

Table 1 Potentiometric titration detection data

According to the measured data in Table 1, calculate according to the calculation formulas of (1-1), (1-2), (1-3), (1-4), (1-5) and (1-6) above . The calculation results of two parallel determinations are shown in Table 2:

Table 2 Measurement results

The present invention is not limited to the above-mentioned embodiments, if the various changes or modifications of the present invention do not depart from the spirit and scope of the present invention, if these changes and modifications belong to the claims of the present invention and the equivalent technical scope, then the present invention is also It is intended that such modifications and variations are included.

Claims (10)

1. Multi-item continuous automatic analysis device in a kind of industrial boiler water quality detection, it is characterized in that: it comprises container, potentiometric titrator main frame, five electrodes and four liquid-adding units; These five electrodes are conductivity electrode, pH electrode respectively , silver electrode, platinum electrode and calcium electrode, the four liquid addition units are standard acid solution addition unit, silver nitrate standard solution addition unit, standard potassium iodate-potassium iodide addition unit and EDTA standard solution addition unit; The five electrodes are placed in the container, and the liquid outlets of the four liquid adding units are all placed in the container. The main body of the potentiometric titrator has five electrode interfaces, and the five electrode interfaces are respectively connected to the conductivity electrode, pH electrode, silver electrode, platinum electrode and calcium electrode, the host of the potentiometric titrator has a built-in titration parameter control and data output control system. 2. The multi-item continuous automatic analysis device in the water quality detection of industrial boilers as claimed in claim 1, characterized in that: the potentiometric titrator host also includes a communication interface connected with the computer, and the control system is connected with the computer through the communication interface. 3. The multi-item continuous automatic analysis device for industrial boiler water quality testing according to claim 1, characterized in that: it also includes an electrode protection unit for accommodating and fixing the five electrodes. 4. The multi-item continuous automatic analysis device in the industrial boiler water quality detection as claimed in claim 1, characterized in that: it also includes a titration stand provided with a stirrer, and the container is placed on the titration stand. 5. The multi-item continuous automatic analysis device for industrial boiler water quality testing according to claim 1, characterized in that: the container is a measuring cup. 6. an analysis method utilizing multi-item continuous automatic analysis device in the industrial boiler water quality detection described in claim 1, is characterized in that, its steps are as follows successively: a. Collect the conductivity of the sample to be measured through the conductivity electrode; b. Turn off the conductivity electrode, turn on the pH electrode and the standard acid solution dosing unit, perform phenolphthalein alkalinity titration and total alkalinity titration on the tested sample, and collect data; c. Close the pH electrode, open the silver electrode and the silver nitrate standard solution dosing unit, carry out the chloride ion potentiometric titration in the tested sample that has completed step b, and collect data; d, turn off the silver electrode, turn on the platinum electrode, the standard acid dosing unit and the standard potassium iodate-potassium iodide dosing unit, after acidifying the sample to be tested in step c, carry out sulfite potentiometric titration, and collect data; e. Turn off the platinum electrode, turn on the calcium electrode and the EDTA standard solution dosing unit, adjust the pH of the sample to be tested after step d to 10, and perform hardness potentiometric titration, and collect data. 7. utilize the analytical method of multi-item continuous automatic analysis device in described industrial boiler water quality detection as claimed in claim 6, it is characterized in that: the standard acid solution in this standard acid solution adding liquid unit is sulfuric acid standard solution, sulfuric acid standard solution The concentration is 8. utilize the analytical method of multi-item continuous automatic analysis device in said industrial boiler water quality detection as claimed in claim 6, it is characterized in that: the titer of the silver nitrate standard solution in this silver nitrate standard solution adding liquid unit is T= 3.34 mg/mL. 9. utilize the analytical method of multi-item continuous automatic analysis device in said industrial boiler water quality detection as claimed in claim 6, it is characterized in that: the potassium iodate-potassium iodide standard solution in this standard potassium iodate-potassium iodide liquid addition unit The titer was T=1.0 mg/mL. 10. utilize the analysis method of multi-item continuous automatic analysis device in said industrial boiler water quality detection as claimed in claim 6, it is characterized in that: the titer of the EDTA standard solution in this EDTA standard solution adding liquid unit is T=0.1mol /L.