JP6471785B1 - Management system for water treatment facilities for power generation boilers - Google Patents

Abstract

Provided is a water treatment facility management system capable of preventing water treatment management and eliminating stable water treatment management without eliminating a drift of pH meter and calibration deviation. A water treatment facility management system stores a first storage means for storing a correlation between electrical conductivity and pH, and an electrical conductivity measured by an electrical conductivity meter and stored in the first storage means. And a management means for obtaining a theoretical pH value based on the calculated correlation and transmitting a signal prompting calibration of the pH meter when the theoretical pH value and the detected pH measurement value of the pH meter deviate by a predetermined value or more. [Selection] Figure 1

Description

  The present invention relates to a water treatment facility management system in which pH is an important water quality management item, such as a water supply system of a boiler, and more specifically, utilizing a correlation between electrical conductivity and pH at a predetermined specified temperature. It is related with the management system of the water treatment facility which performs management.

  As shown in Patent Document 1, the management center of the equipment management system periodically collects equipment operation information of the water treatment equipment to manage the operation state, and refers to the reference information stored in the database while Based on the operation information and the analysis result of the water to be treated, the operation status of the water treatment facility is analyzed in detail, and advice information and maintenance information on the operating conditions useful for operating the water treatment facility are created, and the water treatment facility side To be presented to.

  Verification that the certainty of field instruments can be assured is a major issue for improving the water treatment effect. For example, in the case of a water treatment facility for a power generation boiler, pH is an important management item, and its applicable range is also described in JIS B8223: 2015. Patent Document 2 describes that calibration is performed mutually using a plurality of pH meters, or a correlation at a pH value converted from an electric conductivity meter is observed. In the case of this Patent Document 2, it is necessary to prepare a plurality of pH meters and compare their values, or the pH value itself fluctuates due to the sample temperature and the pH value drifts. It is very difficult to adjust the amount of cooling water so that the on-site sample water temperature is always constant.

Japanese Patent No. 3624941 JP 2002-349804 A

  It is an object of the present invention to provide a water treatment facility management system capable of performing stable water treatment management by preventing water treatment management without eliminating drift and calibration deviation of a pH meter. .

  The water treatment facility management system according to one aspect of the present invention is a water treatment facility management system having a pH meter and an electrical conductivity meter, wherein the first storage means stores the correlation between the electrical conductivity and the pH, and the pH The theoretical pH value is obtained based on the second storage means for storing the correlation between the water temperature and the water temperature, the electrical conductivity measured by the electrical conductivity meter, and the correlation stored in the first storage means. The detected pH value of the pH meter is converted into a pH value of a specified temperature based on the correlation stored in the second storage means and the water temperature, and the theoretical pH value and the converted pH value are different from each other by a predetermined value or more. And a management means for transmitting a signal for prompting calibration of the pH meter.

  A water treatment facility management system according to one aspect of the present invention is a water treatment facility management system having an electrical conductivity meter, a storage unit that stores a correlation between electrical conductivity at a specified temperature and pH, and electrical conductivity. And a means for obtaining a pH value based on the electrical conductivity measured by the meter and the correlation stored in the storage means.

  In one embodiment of the present invention, the specified temperature is 25 ° C.

  In one aspect of the present invention, the water treatment facility is intended for boiler water supply.

  In one aspect of the present invention, the management means transmits an advice signal including adjustment of a chemical injection amount or adjustment of a blow amount.

  According to the present invention, when the pH converted to the pH at the specified temperature deviates by a predetermined value or more from the pH value obtained from the electrical conductivity, a display prompting calibration is made, or the pH is estimated from the electrical conductivity. By doing so, water treatment management based on a pH measurement value having a large error is prevented, and stable water treatment management is performed.

It is a block diagram which shows embodiment. It is a graph which shows the relationship between pH and electrical conductivity. It is a schematic graph which shows the example of control. It is a graph which shows the relationship between pH and temperature.

  Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 shows an example of a water treatment facility management system of the present invention. In a water treatment facility (for example, a water treatment facility for a power generation boiler) 1, an alkaline agent such as ammonia, neutralizing amine, hydrazine is added and injected by a chemical injection device 2.

  A pH meter, an electric conductivity meter, a water temperature meter, and the like are installed as part of the on-site meter 3 that manages the water quality of the water treatment facility 1, and these data are transmitted to a determination device (for example, PLC) 4. The determination device 4 includes a determination unit, a display unit, and a transmission unit. The pH value measured by the pH meter is converted into a pH value at a specified temperature, and the converted pH value is obtained from the electrical conductivity. Data is transmitted to the management center 5 while confirming that there is no deviation from the theoretical pH value. The management center 5 accumulates this information and, if different from the conventional one, compares it with the phenomenon registered in advance in the data analysis section and gives advice such as adjustment of the chemical injection amount and adjustment of the boiler water blow amount. It is displayed on the advice display section 6. As the advice display unit 6, a personal computer, a portable terminal, or the like is used.

  The determination device 4 stores, for example, a pH-temperature relationship line shown in FIG. 4 to be described later in a storage unit, and converts the pH value measured by a pH meter into a pH value at a specified temperature (preferably 25 ° C.). When the pH value deviates from the theoretical pH value obtained from the electrical conductivity of the electrical conductivity meter, an advice display for prompting calibration is displayed on the display unit, and the same content is transmitted to the management center 5. As a result, the same advice display is performed on the advice display unit 6 via the management center 5. This display may be sent by e-mail, or may be displayed on a specific WEB screen, and may be obtained by accessing this WEB screen.

  When the on-site pH meter has a large error in the measured pH value (deviation from the theoretical pH value calculated based on the electrical conductivity of the electrical conductivity meter) due to deterioration, damage, etc., the determination device 4 It is good also as a structure which displays the theoretical pH value converted from electrical conductivity with the determination display part, and transmits to the management center 5. FIG.

  The correlation line between the pH value and the electrical conductivity may be at a temperature such as 20 ° C. or 30 ° C. However, when the water management of the boiler is taken into consideration, for example, 25 in order to comply with JIS B8223 (2015). It is preferable to use a correlation line at ° C.

  The electrical conductivity measured by the electrical conductivity meter is less affected by the temperature (water temperature) compared to the pH value, so it is not necessary to convert the temperature, but for more accurate measurement, the temperature attached to the electrode It is preferable to correct by a conversion function or the like.

  In the present embodiment, as described above, the measured pH value of the pH meter is converted into the pH value of the specified temperature, and when the converted pH value deviates from the theoretical pH value obtained from the electrical conductivity by a predetermined value or more, the calibration instruction display I do. The predetermined value of the deviation is preferably a value selected from 0.1 to 0.5, for example, 0.3 is preferably about 0.2.

  The advice display may include not only a display based on a pH meter and an electric conductivity meter but also a result using a smaller amount of measurement instrument.

  For example, the advice display signal that prompts the calibration of the pH meter may be transmitted together with periodic data transfer every hour, but when the measured pH value deviates from the theoretical value by a predetermined value or more. Is preferably transmitted without delay. A calibration button may be provided, or a mechanism that does not issue a signal prompting calibration within a certain period (for example, 30 minutes) may be provided so that advice for prompting calibration is not generated during calibration of the pH meter.

[Measurement Example 1]
Ammonia and various amines are used as a pH adjuster for boiler feedwater. Therefore, the pH and electrical conductivity at 25 ° C. of boiler feed water to which ammonia, 3-methoxypropylamine or cyclohexylamine was added at various concentrations were measured, and the relationship between them (correlation line) is shown in FIG. As shown in FIG. 2, the logarithmic value of electrical conductivity and pH are in a linear relationship for each type of pH adjuster. Accordingly, when the pH measurement value drift by the pH meter (described later in Example 1) and the error due to temperature (described later in Example 2) are large, the error is obtained by correcting the measured value of the pH meter based on the electrical conductivity. Can be eliminated or reduced.

  FIG. 2 shows a correlation line when only one type of each pH adjuster is added to the boiler feed water. However, the correlation line is similarly applied when a plurality of amines and ammonia are added in combination. And the theoretical pH value based on the electrical conductivity can be obtained based on this correlation line.

[Comparative Example 1, Example 1]
The examination result in the boiler which uses ammonia for pH adjustment of boiler feed water is shown in FIG.

  The pH meter used in Comparative Example 1 and Example 1 had a characteristic that the measured pH value drifted in the negative direction.

  The result of Comparative Example 1 is shown on the left half side of FIG. In Comparative Example 1, the pH meter is calibrated once a month as usual, but temperature conversion is not performed. In Comparative Example 1, the pH was drifting in the negative direction, and the amount of ammonia added was increased, so that the apparent pH (pH meter measured value) was a constant value, Actually, the ammonia concentration in the system was high, and there was a concern about ammonia attack in the condenser.

  The result of Example 1 is shown on the right half side of FIG. As shown in the figure, when using the method of the present invention, the pH was controlled at 25 ° C. converted from the electrical conductivity, so the actual pH was kept constant for 2 months, and appropriate drug administration management continued. It was done.

  From the above, the usefulness of the method for estimating the pH value from the measured value of electrical conductivity was confirmed based on the correlation line between pH and electrical conductivity measured in advance.

[Example 2]
The temperature of the boiler feed water was changed in the range of 18 to 35 ° C., and the pH value was measured. The results are shown in FIG. As shown in FIG. 4, there is a linear relationship between temperature and pH. Therefore, it was revealed that even a pH value measured at a temperature other than 25 ° C. can be converted to a pH value of 25 ° C. by using a conversion formula.

By controlling the chemical injection based on the pH value converted to 25 ° C., it is possible to adjust the chemical injection amount more appropriately. In addition, the conversion formula of FIG. 4 is as follows.
pH [at 25 ° C.] = pH [at M ° C.] + (M−25) × 0.035

1 Water Treatment Equipment 4 Measuring Device 5 Management Center 6 Advice Display Section

Claims (3)

In the management system of the power boiler water treatment facility with a pH meter and conductivity meter,
First storage means for storing a correlation between electrical conductivity and pH;
second storage means for storing the correlation between pH and water temperature;
A theoretical pH value is obtained based on the electrical conductivity measured by the electrical conductivity meter and the correlation stored in the first storage means, and the detected pH value of the pH meter is used as the second storage means. Is converted into a pH value of 25 ° C. , which is the specified temperature , based on the correlation stored in the water temperature and the water temperature , and the theoretical pH value and the converted pH value are selected from 0.1 to 0.5 management system water treatment facility for power generation boiler, characterized in that it comprises a managing means for transmitting a signal for prompting the calibration of the pH meter when deviation above. In the management system for water treatment facility according to claim 1, wherein the water treatment facility management system of water treatment equipment for power generation boiler, characterized in that to target boiler feedwater. In the management system for water treatment facility according to claim 2, wherein the management means, the management system of the water treatment facility for power generation boiler, characterized in that transmits an advice signal including the adjustment of the adjustment or blow amount of chemical feeding, chemical dosing quantity.

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