JP2023005680A - Water treatment chemicals measurement device and measurement method - Google Patents

Abstract

A water treatment chemical measuring apparatus and method capable of accurately measuring the fluorescent substance concentration in circulating cooling water of a cooling tower without being affected by temperature, external light, and air bubbles. A water treatment chemical measuring device 3 for measuring the concentration of a water treatment chemical in circulating cooling water of a cooling tower 1, in which a water treatment chemical and a fluorescent substance as a tracer substance are added to the circulating cooling water. A fluorometer 20 for optically measuring the fluorescence of a fluorescent substance present in the circulating cooling water, which has an addition means and a measurement unit 46 including a fluorescence light receiving unit, and at least the fluorescence light receiving unit of the measurement unit 46 is , immersed in a lower water tank 10 that stores circulating cooling water in the cooling tower 1, and is shielded so as to suppress external light entering from the outside of the cooling tower 1 from entering the fluorescent light receiving portion. It is a measuring device 3 for chemicals. [Selection drawing] Fig. 1

Description

The present invention relates to a water treatment chemical measuring apparatus and method for measuring the concentration of a water treatment chemical in circulating cooling water of a cooling tower.

As is well known, industrial water plays an important role in all industries and is often used in circulating water systems. Commonly used circulating water systems include boiler water systems, open and closed cooling water systems, etc. There is

Various sensors are used for water quality control of these circulating water systems. In cooling towers, these sensors are installed in a water tank at the bottom of the cooling tower to measure water quality.

In addition, various water treatment chemicals (medicine) are used in the water treatment of these circulating water systems in order to suppress troubles caused by water such as corrosion, scale, and slime. In order to maintain the effects of these water treatment chemicals, it is necessary to accurately ascertain the concentration of these chemicals at any position, time, etc., and perform appropriate concentration control. In addition, as a concentration control method when using a water treatment chemical whose concentration is impossible or difficult to measure, a substance whose concentration can be easily measured is used as a tracer.

In Patent Document 1, a conductivity meter and an oxidation-reduction potential meter are used as sensors installed in the lower water tank of the cooling tower.

As a tracer substance, a method using a sulfonated pyrene compound, which is a fluorescent substance, has been proposed. For example, Patent Literatures 2 and 3 propose, as a method for measuring the sulfonated pyrene compound, a method in which a fluorescence photometer is installed in a flow path of a circulating water system.

Another tracer substance is the use of lithium. For example, Patent Document 4 proposes a method of vertically immersing a lithium ion electrode in a lower water tank of a cooling tower as a method for measuring lithium. Further, in Patent Document 4, the lithium ion sensitive film is covered with a light-shielding cover in order to suppress biofilm adhesion to the lithium ion sensitive film.

Patent Document 5 proposes a sensor installation method in which the detection surface of the dissolved oxygen electrode is installed in the same direction as the upward direction of air bubbles in the aeration tank. In this method, since the detection surface is oriented vertically, there is no accumulation of air bubbles, and therefore it is possible to stably and accurately measure water quality.

In Patent Document 1, as shown in FIG. 2, a pH meter, a conductivity meter, and an oxidation-reduction potential meter are installed in the lower water tank of the cooling tower, but these are not fluorometers. In Patent Document 4, a sensor for optical measurement using a lithium ion functional membrane is installed in the lower water tank of the cooling tower, but an ion optode is used to detect the fluorescence of fluorescent substances present in the water to be treated. It is not a fluorometer that optically measures

In Patent Literature 2, a fluorescence photometer is used by inserting it into a pipe that is a channel of a circulating water system. However, this method has the following problems.
(1) If there is a difference between the water temperature and the outside air temperature, temperature drift may occur and accurate measurement may not be possible.
(2) When a transparent tube is used, external light enters and optical effects sometimes make it impossible to measure accurately.
(3) In order to prevent outside light from entering when using a transparent pipe, there are restrictions on the mounting locations.
(4) When the tee fitting is installed horizontally, an air pocket may occur, preventing accurate measurement.
(5) There are restrictions on the mounting direction of the tee fitting, and it may be difficult to mount depending on the surrounding conditions.
(6) It is necessary to take out the fluorescence photometer from the pipe for maintenance or calibration, which is a complicated operation, and there is a possibility that the water to be treated may leak out of the system.

Patent Literature 3 describes a method of automatically sampling water to be treated and measuring it with a fluorometer in a channel. However, this method has the following problems in addition to the problems (2), (3), and (6) above.
(7) It takes time from sampling to fluorescence measurement, and the water temperature may change during that time, making accurate measurement impossible.

In Patent Document 5, the dissolved oxygen electrode is installed so that the detection surface is in the same direction as the specific traveling direction (upward direction) of the bubbles in the aeration tank, thereby suppressing the stagnation of the bubbles. However, unlike the aeration tank, the lower water tank of the cooling tower is not aerated. Inside the cooling tower, water is sprayed from the top of the cooling tower, so the bubbles in the lower water tank of the cooling tower are dancing, and there are many bubbles that do not have a specific progress. Therefore, when this method is applied to the lower water tank of the cooling tower, there are the following problems.
(8) The direction of the detection surface was not fixed, and it was difficult to install.

In Patent Document 4, the lithium ion sensitive film is covered with a light-shielding cover in order to suppress biofilm adhesion to the lithium ion sensitive film. However, this method has the following problems.
(9) It is difficult to remove the biofilm once adhered.

Japanese Patent Application Laid-Open No. 2006-098003 U.S. Pat. No. 7,099,012 Japanese translation of PCT publication No. 2003-532049 Japanese Patent Application Laid-Open No. 2004-004045 Japanese Utility Model Publication No. 7-010288

SUMMARY OF THE INVENTION It is an object of the present invention to provide a water treatment chemical measuring apparatus and method capable of accurately measuring the fluorescent substance concentration in the circulating cooling water of a cooling tower without being affected by temperature, external light, and air bubbles. .

The present invention is a water treatment chemical measuring apparatus for measuring the concentration of a water treatment chemical in the circulating cooling water of a cooling tower, wherein the water treating chemical and a fluorescent substance as a tracer substance are added to the circulating cooling water. and a fluorescence photometer for optically measuring the fluorescence of the fluorescent substance present in the circulating cooling water, wherein at least the fluorescence light receiving portion of the measuring portion comprises , immersed in a lower water tank storing the circulating cooling water in the cooling tower, and shielding so as to suppress external light entering from the outside of the cooling tower from entering the fluorescence light receiving part of the fluorescence photometer It is a measuring device for water treatment chemicals.

In the apparatus for measuring water treatment chemicals, it is preferable that the fluorescence photometer has a cleaning function for cleaning the fluorescence receiving part.

In the apparatus for measuring water treatment chemicals, it is preferable to control the concentration of the water treatment chemicals in the circulating cooling water based on the measured value of the fluorescence photometer.

The present invention is a water treatment chemical measuring method for measuring the concentration of a water treatment chemical in the circulating cooling water of a cooling tower, wherein the water treatment chemical and a fluorescent substance as a tracer substance are added to the circulating cooling water. and a fluorescence measurement step of optically measuring the fluorescence of the fluorescent substance present in the circulating cooling water with a fluorescence photometer having a measurement unit including a fluorescence light receiving unit, wherein at least the fluorescence of the measurement unit The light receiving unit is immersed in a lower water tank storing the circulating cooling water in the cooling tower, and suppresses external light entering from the outside of the cooling tower from entering the fluorescence light receiving unit of the fluorescence photometer. It is a method for measuring water treatment chemicals that are shielded from light.

In the method for measuring water treatment chemicals, it is preferable that the fluorescence photometer has a cleaning function for cleaning the fluorescence receiving part.

In the method for measuring the water treatment chemicals, it is preferable to control the concentration of the water treatment chemicals in the circulating cooling water based on the measured value of the fluorescence photometer.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a water treatment chemical measuring apparatus and method capable of accurately measuring the fluorescent substance concentration in the circulating cooling water of a cooling tower without being affected by temperature, external light, and air bubbles.

1 is a schematic configuration diagram showing an example of a cooling tower equipped with a water treatment chemical measuring device according to an embodiment of the present invention; FIG. 1 is a schematic configuration diagram showing an example of a measuring section of a fluorometer in a water treatment chemical measuring apparatus according to an embodiment of the present invention; FIG. FIG. 4 is a schematic configuration diagram ((a): side view, (b): plan view) showing another example of the measurement unit of the fluorescence photometer in the water treatment chemical measuring device according to the embodiment of the present invention. FIG. 4 is a schematic configuration diagram ((a): side view, (b): plan view) showing another example of the measurement unit of the fluorescence photometer in the water treatment chemical measuring device according to the embodiment of the present invention. It is a schematic diagram showing an example of a method of immersing the measurement part of the fluorescence photometer in the water treatment chemical measuring device according to the embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of a light shielding member attached to the measurement unit of the fluorescence photometer in the water treatment chemical measuring device according to the embodiment of the present invention. 1 is a schematic configuration diagram showing an open circulation cooling tower simulator used in Example 1 and Comparative Example 1. FIG. 5 is a graph showing water temperature (° C.) and measurement error (%) versus operation time (hr) in Example 1 and Comparative Example 1. FIG. 2 is a schematic configuration diagram showing an open circulation cooling tower simulator used in Example 2 and Comparative Example 2. FIG. 5 is a graph showing water temperature (° C.) and measurement error (%) versus operating time (hr) in Example 2 and Comparative Example 2. FIG. FIG. 11 is a schematic configuration diagram showing an open circulation cooling tower simulator used in Comparative Example 3; FIG. 2 is a schematic configuration diagram showing an open circulation cooling tower simulator used in Example 3. FIG. 10 is a graph showing measured values (μg/L) of PTSA versus rotation angles (°) of a fluorometer in Comparative Example 3 and Example 3. FIG. FIG. 11 is a schematic diagram showing how light enters the fluorescence light receiving portion of the fluorescence photometer in Comparative Example 3; FIG. 10 is a schematic diagram showing how light enters the fluorescence light receiving part of the fluorescence photometer in Example 3; FIG. 10 is a schematic configuration diagram showing an open circulation cooling tower simulator used in Example 4. FIG. 10 is a graph showing the bacterial logarithm (CFU/mL) and measurement error (%) versus operating time (hr) in Example 4. FIG.

An embodiment of the present invention will be described below. This embodiment is an example of implementing the present invention, and the present invention is not limited to this embodiment.

An outline of an example of a cooling tower equipped with a water treatment chemical measuring device according to an embodiment of the present invention is shown in FIG. 1, and the configuration thereof will be described.

The cooling tower 1 shown in FIG. 1 is, for example, an open circulation cooling water cooling tower that cools the circulating cooling water by bringing the circulating cooling water into contact with outside air. The cooling tower 1 has a lower water tank 10 at the bottom, a fan 12 at the top for taking outside air into the cooling tower 1, a filler 16 on the outer periphery of the tower, and a sprinkler tank above the filler 16. 14. A cross plate 18, which is a plate-like member, may be installed at a predetermined distance above the water surface of the lower water tank 10 so as to be parallel to the water surface. For example, the lower side surface of the lower water tank 10 and the sprinkler tank 14 are connected by a circulation pipe 30 via a circulation pump 22 and a heat exchanger 24 .

The water treatment chemical measuring device 3 is a device for measuring the concentration of the water treatment chemical in the circulating cooling water of the cooling tower 1 by measuring the concentration of a fluorescent substance, which is a tracer substance. The water treatment chemical measuring device 3 includes a chemical tank 26, a chemical pump 28, and a chemical pipe 32 as addition means for adding a water treatment chemical and a fluorescent substance as a tracer substance to the circulating cooling water. and a fluorometer 20 for optically measuring the fluorescence of fluorescent substances present in the circulating cooling water.

The structure of the fluorometer 20 includes, for example, an excitation light source, an optical filter for selecting a particular excitation wavelength to match the fluorophore and the fluorescence properties of the fluorophore, and the excitation light exiting the fluorometer. an excitation light emitting part that allows the excitation light to be emitted, a fluorescence receiving part that allows the fluorescence of a fluorescent substance present in the water to be treated (here, circulating cooling water) to enter the fluorometer, and an optical for selecting a specific fluorescence wavelength a filter, a light-receiving element having a function of converting the state of fluorescence into an electrical signal, a measurement unit 46 including a filter, and a calculation unit 36 that receives the electrical signal and calculates the concentration of water treatment chemicals. . The fluorometer 20 may include a receiving section 34 for receiving a signal input from the light receiving element of the measuring section 46, and a control section 38 for determining the amount of water treatment chemicals to be added to the water to be treated.

For example, as shown in FIG. 2, the fluorometer 20 includes an excitation light emitting part/fluorescence receiving part 40 on one end surface of a measuring part 46 such as a cylindrical shape, an excitation light source 42, and a light receiving part 40. The excitation light emitted from the excitation light source 42 is transmitted through the excitation light emitting portion/fluorescence receiving portion 40 and emitted, and the measurement target absorbs the excitation light and then emits fluorescence, and the excitation light emitting portion / The structure is such that the fluorescence transmitted through the fluorescence light receiving section 40 can be received by the light receiving element 44 . The emitting surface/receiving surface of the excitation light emitting portion/fluorescence receiving portion 40 has a flat shape.

As another structure of the fluorometer 20, as shown in FIG. 3, the emitting surface/light receiving surface of the excitation light emitting portion/fluorescence receiving portion 40 is curved inside one end portion of the hollow cylindrical shape of the measuring portion 46. It may be a structure provided by doing. The excitation light emitted from the excitation light source 42 is emitted through, for example, the curved excitation light emitting portion/fluorescence receiving portion 40, and the measurement target passing through the curved excitation light emitting portion/fluorescence receiving portion 40 absorbs the excitation light. After that, fluorescence is emitted, and the fluorescence transmitted through the curved excitation light emitting portion/fluorescence receiving portion 40 can be received by the light receiving element 44 . The angle formed by the excitation light source 42 and the light receiving element 44 is not particularly limited.

As another structure of the fluorometer 20, as shown in FIG. 4, an excitation light emitting portion/fluorescence receiving portion is provided on the surface or inside of one end portion of a measuring portion 46 having a cylindrical shape or the like. It may be separated from the light receiving portion 40b and arranged in an L shape, for example. The excitation light emitted from the excitation light source 42 is transmitted through the excitation light emitting portion 40a and emitted, the measurement target absorbs the excitation light and emits fluorescence, and the fluorescence transmitted through the fluorescence light receiving portion 40b is received by the light receiving element 44. It is configured to be able to receive light. The angle formed by the excitation light emitting portion 40a and the fluorescence receiving portion 40b is not particularly limited. The angle formed by the excitation light source 42 and the light receiving element 44 is not particularly limited.

As shown in FIG. 1, the measurement part 46 of the fluorometer 20 is immersed in the lower water tank 10 that stores the circulating cooling water in the cooling tower 1 . That is, at least the excitation light emitting portion/fluorescence receiving portion of the measuring portion 46 is immersed in the lower water tank 10 . Further, as will be described later, the light is shielded so as to prevent external light entering from the outside of the cooling tower 1 from entering the fluorescence light receiving portion of the measuring portion 46 .

Here, the external light is light that enters the inside of the cooling tower after direct, reflection, scattering, or transmission from the outside of the cooling tower. Types of external light include, for example, sunlight, direct light emitted from fluorescent lamps, LED lamps, mercury lamps, halogen lamps, etc., and light reflected, scattered, or transmitted in the environment outside the cooling tower. , as well as combinations thereof.

A chemical liquid outlet, for example, on the lower side of the chemical liquid tank 26 and a chemical liquid inlet, for example, on the upper side of the lower water tank 10 of the cooling tower 1 are connected by a chemical liquid pipe 32 via a chemical liquid pump 28 .

The water treatment chemical measuring device 3 includes a receiver 34 , a calculator 36 and a controller 38 . The receiving unit 34 and the measuring unit 46 are communicably connected by a wired or wireless electrical connection or the like. The control unit 38 and the chemical pump 28 are communicably connected by a wired or wireless electrical connection or the like.

The operation of the cooling tower 1 and the water treatment chemical measuring device 3 will be described.

In the cooling tower 1, the circulating cooling water stored in the lower water tank 10 of the cooling tower 1 is sent to the heat exchanger 24 through the pipe 30 by the circulating pump 22 from the circulating cooling water outlet. The cooling water is heat-exchanged with the refrigerant of the cooling tower 1 , and the temperature of the cooling water is increased. The cooling water stored in the sprinkler tank 14 is sprinkled from the top of the cooling tower 1 into the filler 16 . The sprayed circulating cooling water comes into contact with the air taken in from the outside by the fan 12 in the filling material 16, a part of which evaporates, and the latent heat of evaporation is released to become cooling water whose water temperature has been lowered, thereby cooling the water. It drops into the lower water tank 10 of the tower 1 and is stored. The circulation cooling water stored in the lower water tank 10 is sent to the heat exchanger 24 through the piping 30 by the circulation pump 22 as described above. In this manner, the circulating cooling water is circulated.

On the other hand, the water treatment chemicals stored in the chemical liquid tank 26 and the fluorescent substance as the tracer substance are added by the chemical liquid pump 28 through the chemical liquid pipe 32 to the circulating cooling water stored in the lower water tank 10 of the cooling tower 1 (addition step ). Fluorescence of fluorescent substances present in the circulating cooling water is optically measured by a fluorophotometer 20 having a measurement part 46 in which at least a fluorescence receiving part is immersed in the lower water tank 10 of the cooling tower 1 (fluorescence measurement step). Specifically, the excitation light emitted from the excitation light source 42 of the measurement unit 46 shown in FIGS. Fluorescence is emitted after absorbing the excitation light, and the fluorescence transmitted through the excitation light emitting portion/fluorescence receiving portion 40 or the fluorescence receiving portion 40b is received by the light receiving element 44 .

The receiving section 34 receives the signal input from the light receiving element 44 of the measuring section 46 (receiving step). The calculation unit 36 converts the signal received by the reception unit 34 into the concentration of the fluorescent substance contained in the circulating cooling water using, for example, a pre-stored calibration curve, and then converts the signal received by the reception unit 34 to the water system in advance for water treatment. When the ratio of the added amount of chemicals and the added amount of fluorescent substance is known as a known coefficient (chemical concentration conversion coefficient by fluorescent substance), by multiplying the concentration of fluorescent substance by the coefficient, Calculate the concentration. Alternatively, another calibration curve stored in advance may be used to convert the concentration of the water treatment chemicals contained in the circulating cooling water (calculation step). The control unit 38 calculates the required addition amount of the water treatment chemical based on the concentration of the water treatment chemical calculated by the calculation unit 36 . The control unit 38 may control the driving of the chemical liquid pump 28 through the control line based on the calculated addition amount of the water treatment chemical (control step).

Thus, by measuring the concentration of the fluorescent substance, which is the tracer substance, in the circulating cooling water, the concentration of the water treatment chemical in the circulating cooling water is measured. The concentration of the water treatment chemical in the circulating cooling water is controlled based on the concentration of the water treatment chemical in the circulating cooling water measured by a fluorometer, and the required amount of the water treatment chemical may be added. .

With the apparatus and method for measuring water treatment chemicals according to the present embodiment, the fluorescent substance concentration in the circulating cooling water of the cooling tower 1 can be accurately measured without being affected by temperature, external light, and air bubbles.

By immersing at least the excitation light emitting part/fluorescence receiving part 40 of the measuring part 46 of the fluorophotometer 20 in the lower water tank 10 of the cooling tower 1, the measuring part 46 is suppressed from coming into contact with the outside temperature, and temperature drift is prevented. It can be resolved (solution of (1) above). In addition, sampling of the circulating cooling water is not required, the loss of time until measurement can be reduced, and changes in water temperature during measurement can be suppressed (elimination of (7) above). Since the flow of air bubbles in the lower water tank 10 is not uniform, it is difficult for air bubbles to accumulate and accurate measurement can be performed (elimination of the above (4)). The direction of the detection surface of the measurement unit 46 (excitation light emitting unit/fluorescence receiving unit 40 or fluorescence receiving unit 40b) can be arbitrarily determined in the lower water tank 10, and there are almost no restrictions on attachment ((3) above, ( 5), elimination of (8)). The measuring part 46 can be easily taken out from the lower water tank 10, the work becomes easier, and the circulating cooling water hardly leaks out of the system (solution of the above (6)).

In addition, as will be described later, the excitation light emitting portion/fluorescence receiving portion 40 of the measurement portion 46 is shielded from light, thereby reducing the optical influence and making it possible to perform accurate measurement (elimination of (2) above). ).

In the apparatus and method for measuring water treatment chemicals according to the present embodiment, biofilms and the like adhering to the surface of the excitation light emitting unit/fluorescence receiving unit 40 may affect the measurement accuracy. may have a cleaning function of cleaning the excitation light emitting portion/fluorescence receiving portion 40 of the measuring portion 46 . By providing a cleaning function for cleaning the surface of the excitation light emitting section/fluorescence receiving section 40, the measurement accuracy can be greatly improved. The cleaning function is not particularly limited as long as the surface of the excitation light emitting portion/fluorescence receiving portion 40 of the measuring portion 46 can be cleaned. A wiper made of rubber or the like for cleaning the light-receiving portion 40 or a jet (pulse) injector for spraying a gas such as air may be provided. By providing a cleaning function such as a wiper or a jet (pulse) sprayer, it is possible to easily remove the biofilm adhering to the excitation light emitting section/fluorescence receiving section 40 (solution of (9) above).

In the water treatment chemical measuring apparatus and measuring method according to the present embodiment, the concentration of the water treatment chemical in the circulating cooling water can be controlled based on the measured value of the fluorophotometer 20, as described above. Accurate concentration control can be performed by obtaining accurate measurement values with little loss of time.

Excitation light source 42 is a light source that emits light within a selected wavelength range.

An optical filter for selecting a particular excitation wavelength may be placed, for example, between the excitation light source 42 and the excitation light emitter/fluorescence receiver 40 . This optical filter has a function of transmitting a predetermined wavelength from the excitation light source 42 .

The excitation light emitting portion or the excitation light emitting portion 40a in the excitation light emitting portion/fluorescence receiving portion 40 may transmit the excitation light, and is made of glass, plastic, or the like, for example.

The fluorescence receiving portion or the fluorescence receiving portion 40b in the excitation light emitting portion/fluorescence receiving portion 40 may transmit fluorescence, and is made of glass, plastic, or the like, for example.

The angle of the excitation light emitting portion/fluorescence receiving portion 40 may be set at any angle.

An optical filter for selecting a specific fluorescence wavelength may be placed, for example, between the excitation light emitter/fluorescence receiver 40 and the light receiving element 44 . This optical filter has the function of transmitting a predetermined wavelength from fluorescence.

The light receiving element 44 is a part that has a function of converting fluorescence into an electric signal, and has a function of converting it into an analog signal or a digital signal and outputting it. A photodiode, a phototransistor, a photomultiplier tube, or the like may be used as the light receiving element 44 .

The receiving section 34 has a function of receiving a signal input from the light receiving element 44 of the measuring section 46 .

The computing unit 36 has a function of converting the signal received by the receiving unit 34 into the fluorescent substance concentration contained in the circulating cooling water using, for example, a pre-stored calibration curve.

The control unit 38 has a function of calculating the addition amount of the water treatment chemical using the fluorescent material concentration calculated by the calculation unit 36 and controlling the drive of the chemical liquid pump 28 and the like through the control line.

The calculation unit 36 may be one that can be considered in isolation from the reception unit 34 or one that cannot be considered in isolation from the reception unit 34 , that is, may include the reception unit 34 .

The receiving unit 34, the computing unit 36 and the control unit 38, or the computing unit 36 and the control unit 38 may be the same unit device, and it is preferable to use a programmable controller, computer, or the like.

As a method for calculating the concentration of the fluorescent substance, if the relationship between the concentration of the fluorescent substance and the electrical signal of the fluorophotometer 20 (for example, a calibration curve) is known in advance, for example, at an appropriate sampling position and time, the water to be treated The concentration of the fluorescent substance in (here, the circulating cooling water) can be detected.

As a method for calculating the concentration of water treatment chemicals, the ratio between the amount of water treatment chemicals added to the water system and the amount of fluorescent substance added is known in advance as a known coefficient (chemical concentration conversion coefficient by fluorescent substance). For example, by detecting the concentration of the fluorescent substance in the water to be treated (here, circulating cooling water) at an appropriate sampling position and time, and multiplying the value by a coefficient, the concentration of the water treatment chemical can be calculated. Based on this calculated value, it is possible to calculate the amounts of the necessary water treatment chemical and fluorescent substance to be added to the circulating cooling water.

The water treatment chemical measuring device 3 includes a sensor for measuring temperature, a sensor for measuring pH, a sensor for measuring electrical conductivity, a sensor for measuring chloride ion, a sensor for measuring chloride ion, a sensor for measuring Sensors intended to measure ions, sensors intended to measure consumption of at least one of acid and alkali, sensors intended to measure hardness, sensors intended to measure silica, sensors intended to measure iron sensor for measuring copper, sensor for measuring ammonium ion, sensor for measuring carbonic acid, sensor for measuring oxidation-reduction potential (ORP), sensor for measuring oxidant At least one of a sensor for measurement, a sensor for measurement of corrosion, a sensor for measurement of scale, and a sensor for measurement of slime may be provided as necessary.

Examples of fluorescent substances include sulfonated pyrene compounds (1,3,6,8-pyrenetetrasulfonic acid sodium salt as a typical substance), uranin, fluorescein, phycoerythrin, phycocyanin, rhodamine, and the like. The fluorescent substance is not particularly limited as long as it is a chemical substance that absorbs a specific wavelength and emits a wavelength (fluorescence) different from that wavelength.

As for the concentration of the fluorescent substance in the circulating cooling water, an extremely small amount in the range of about 0.1 to 10000 μg/L (ppb) functions sufficiently as a tracer, so this concentration range is acceptable. In such a concentration range, the calibration curve for fluorescent substance concentration usually has sufficient reproducibility. If the concentration is less than 0.1 μg/L, the photosensitivity may be insufficient. From the viewpoint of economic efficiency, etc., the concentration of the fluorescent substance in the circulating cooling water should be 0.1 to 10000 μg/L.

At least the excitation light emitting part/fluorescence receiving part 40 of the measuring part 46 is immersed in the lower water tank 10 of the cooling tower 1 . It is preferable that the entire measuring part 46 is immersed in the lower water tank 10 of the cooling tower 1 .

Regarding the immersion location in the lower water tank 10 of the cooling tower 1, at least the excitation light emitting part/fluorescence receiving part 40 of the measurement part 46 should be immersed under the water surface in the lower water tank 10, preferably during operation. It is preferable to immerse in a place where the circulating cooling water in the cooling tower 1 is not stationary, more preferably in a place where the circulating cooling water in the cooling tower 1 in operation has a flux of 0.001 m / s or more. Better to

On the emitting surface/receiving surface of the excitation light emitting part/fluorescence receiving part 40 of the measurement part 46 immersed in the lower water tank 10 of the cooling tower 1, the emitting surface of the excitation light emitting part 40a or the light receiving surface of the fluorescence receiving part 40b, For example, it may be angled as shown in FIG. By angling the emitting surface/receiving surface of the excitation light emitting portion/fluorescence receiving portion 40, the emitting surface of the excitation light emitting portion 40a, or the light receiving surface of the fluorescence receiving portion 40b, it becomes more difficult for air bubbles to accumulate. For example, when the measurement unit 46 is rotated around the center of the cylindrical measurement unit 46, the emission surface/light reception surface of the excitation light emission unit/fluorescence reception unit 40, the emission surface of the excitation light emission unit 40a, or the fluorescence reception unit When the angle formed by the light receiving surface of 40b and the still water surface of the lower water tank is 90° when the axis of the measurement unit 46 is horizontal, the excitation light emitting part/light emitting surface/light receiving surface of the fluorescence light receiving part 40, excitation light emitting The angle formed by the emission surface of the portion 40a or the light receiving surface of the fluorescent light receiving portion 40b and the still water surface of the lower water tank is, for example, in the range of 0° to 180°, preferably in the range of 0° to 180°. ° or more and 180° or less. When the fluorescence photometer 20 shown in FIG. 4 is used, it is preferable that the light receiving surface of the fluorescence light receiving portion 40b is in the above-described angle range rather than the emitting surface of the excitation light emitting portion 40a.

Here, the still water surface is the water surface without waves. In the lower water tank 10 of the cooling tower 1, when water is sprayed from the top of the cooling tower 1, when wind flows into the cooling tower 1 from the outside of the cooling tower 1, or when the outside of the cooling tower 1 When the vibration is transmitted to the lower water tank 10 of the cooling tower 1, waves may occur on the water surface. Therefore, the static water surface of the lower water tank 10 is when water is not sprayed from the upper part of the cooling tower 1, when wind does not flow into the cooling tower 1 from the outside of the cooling tower 1, or when the cooling tower 1 It refers to the water surface when no waves are generated on the water surface when external vibrations are not transmitted to the lower water tank 10 of the cooling tower 1 .

As a light shielding method for the excitation light emitting unit/fluorescence receiving unit 40 of the measurement unit 46, the direct light of the external light to the inside of the cooling tower 1, the reflected light of the external light inside the cooling tower 1, and the scattered light are excited. Any form may be used as long as it suppresses the entry of light into the light emitting portion/fluorescence receiving portion 40. For example, as shown in FIG. You may install so that 40 may be arranged. A dedicated light shielding member may be attached to the measurement unit 46 in order to further enhance the light shielding performance against external light, direct light, reflected light, scattered light, and the like.

For example, as shown in FIG. 6, the dedicated light shielding member 50 may have a structure covering only the excitation light emitting section/fluorescence receiving section 40 or a structure covering the entire measurement section 46 . The light shielding member 50 has a structure in which external light, direct light, reflected light in the cooling tower, scattered light, etc. do not directly enter the excitation light emitting portion/fluorescence receiving portion 40, and circulating cooling water flows inside. For example, any structure having flow holes is acceptable, and there is no particular limitation. The light shielding member 50 has, for example, a multi-layered structure in which two or more cylindrical bodies are arranged in multiples. The other end of one cylindrical body is sealed, the side surface of each cylindrical body is formed with a flow hole for passing circulating cooling water, and at least a part of the flow hole of the outermost cylindrical body is connected to the other. , or a commercially available cheese joint for PVC pipes may be used. The material of the light shielding member 50 is not particularly limited as long as it has durability in the circulating cooling water and does not adversely affect both the fluorometer 20 and the circulating cooling water system as much as possible. As the material of the light shielding member 50, for example, black colored plastics or metals may be used.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Experiment 1 (influence confirmation test when the sensor is immersed)]
<Example 1, Comparative Example 1>
Under the following conditions, a test was conducted to confirm the effect of immersing the measuring part of the fluorophotometer.

(Experimental conditions)
Raw water: Sagamihara city water Equipment: Open circulation cooling tower simulator (Fig. 7)
Fluorometer: Little Dipper 2 manufactured by Turner Design (measurement unit is configured as shown in Fig. 2)
Stationary fluorescence photometer: Shimadzu RF-5300PC
Fluorescent substance: 1,3,6,8-pyrenetetrasulfonic acid sodium salt Fluorescent substance concentration: Adjusted so that the concentration in the circulating cooling water becomes 70 μg/L

As shown in FIG. 7, the circulating water outlet at the bottom of the water tank 52 and the circulating water inlet at the top were connected by a circulation pipe 60 via a circulation pump 54 . Two sets of the same measurement unit 46 of the fluorometer were prepared. (Comparative Example 1). Each measurement unit 46 was electrically connected to the data logger 58 so as to be communicable. The measuring part 46 immersed in the water tank 52 was installed so that the angle formed by the excitation light emitting part/fluorescence receiving part 40 and the still water surface of the lower water tank was 90°. The water tank 52 was covered with a blackout curtain to shield the whole from light.

The fluorescence of the circulating cooling water was measured using each of the two measurement units 46 . In addition, the fluorescence of the circulating cooling water was measured using a stationary fluorophotometer. Calculation of the measurement error was performed using Equation 1 below. It means that the closer the error value is to 0%, the more accurate the measurement is.

Error [%] = (Measured value with fluorometer - Measured value with stationary fluorometer) / (Measured value with stationary fluorometer) Equation 1

FIG. 8 shows the water temperature (°C) and measurement error (%) against the operation time (hr). The measurement error was smaller when the measurement part 46 of the fluorometer was immersed in the water tank 52 than when it was inserted into the circulation pipe 60 . This is probably because the temperature difference between the water temperature and the outside air temperature can be eliminated by immersing the measurement part 46 of the fluorescence photometer in the water tank 52 .

[Experiment 2 (influence confirmation test when part of the sensor is immersed)]
<Example 2, Comparative Example 2>
Under the following conditions, a test was conducted to confirm the effect of immersing the measuring part of the fluorophotometer.

(Experimental conditions)
Raw water: Sagamihara city water Equipment: Open circulation cooling tower simulator (Fig. 9)
Fluorometer: Turner Design Little Dipper 2
Stationary fluorescence photometer: Shimadzu RF-5300PC
Fluorescent substance: 1,3,6,8-pyrenetetrasulfonic acid sodium salt Fluorescent substance concentration: Adjusted so that the concentration in the circulating cooling water becomes 70 μg/L

As shown in FIG. 9, two sets of the same measurement unit 46 of the fluorescence photometer are prepared, and one of them is placed in a water tank 52 of the open circulation cooling tower simulator as part of the measurement unit 46 (excitation light emission unit/ The fluorescent light receiving part 40) was immersed (Example 2), and the other was inserted into a T-shaped tubular member 56 provided in the middle of the circulation pipe 60 (Comparative example 2). Moreover, a sprinkler pipe 64 was installed above the water tank 52, and showering was performed in the open circulation cooling tower simulator. Each measurement unit 46 was electrically connected to the data logger 58 so as to be communicable. The measurement part 46 immersed in the water tank 52 was installed so that the angle formed by the excitation light emitting part/fluorescence receiving part 40 and the still water surface of the lower water tank was 30°. The water tank 52 was covered with a blackout curtain to shield the whole from light.

The fluorescence of the circulating cooling water was measured using each of the two measurement units 46 . In addition, the fluorescence of the circulating cooling water was measured using a stationary fluorophotometer. Calculation of the measurement error was performed using Equation 1. It means that the closer the error value is to 0%, the more accurate the measurement is.

FIG. 10 shows the water temperature (°C) and the measurement error (%) against the operation time (hr). When a part of the measuring part 46 of the fluorophotometer is immersed in the water tank 52 , the measurement error is smaller than when it is inserted into the circulation pipe 60 . This is probably because the temperature difference between the outside air temperature and the water temperature was eliminated by performing showering in the open circulation cooling tower simulator, which raised the temperature of the gas phase inside the system.

[Experiment 3 (verification of effect of light shielding member)]
A test for verifying the effect of the light shielding member was conducted under the following conditions.

<Comparative Example 3: No light shielding member>
Raw water: Sagamihara city water Equipment: Open circulation cooling tower simulator (Fig. 11)
Fluorometer: Turner Design Little Dipper 2
Fluorescent substance: 1,3,6,8-pyrenetetrasulfonic acid sodium salt Fluorescent substance concentration: Adjusted so that the concentration in the circulating cooling water is 120 μg/L

As shown in FIG. 11, the measurement part 46 of the fluorometer was entirely immersed in the water tank 52 of the open circulation cooling tower simulator. Two artificial sunlight light sources 62 were installed above the water tank 52 to artificially generate sunlight and irradiate the water tank 52 from above. Also, a sprinkler pipe 64 was installed above the water tank 52 and below the artificial sunlight light source 62 , and showering was performed in the open circulation cooling tower simulator to generate air bubbles in the water tank 52 . In Comparative Example 3, the measurement part 46 was immersed in the water tank 52 of the open circulation cooling tower simulator without attaching a light shielding member, and the angle formed by the excitation light emitting part/fluorescence receiving part 40 and the static water surface of the lower water tank was measured. When the center axis of the portion 46 is horizontal, the angle formed by the excitation light emitting portion/fluorescence receiving portion 40 and the static water surface of the lower water tank is rotated in the range of 0° to 180°. FIG. 13 shows the measured PTSA values (μg/L) versus the rotation angle (°) of the fluorometer.

At 0°, bubbles accumulated in the fluorescence receiving part of the measuring part 46, and accurate measurement was impossible. At 30° to 90°, almost no air bubbles were accumulated, but light with the same wavelength as the fluorescence of the fluorescent material contained in the artificial sunlight changes its angle due to refraction and scattering by the air bubbles, and reaches the fluorescence receiving part. It is assumed that the measured value is higher than the measured value due to the incident light, the light of the same wavelength as the fluorescence of the fluorescent substance whose angle has changed, and the fluorescence of the fluorescent substance emitted by the excitation light. assumed (see FIG. 14). In the range from 135° to 180°, it is considered that the fluorescent light receiving part received the external light as well as the fluorescent light, so that the fluorescence intensity decreased relatively and the measured value decreased.

<Example 3: With light shielding member>
Raw water: Sagamihara city water Equipment: Open circulation cooling tower simulator (Fig. 12)
Fluorometer: Turner Design Little Dipper 2
Fluorescent substance: 1,3,6,8-pyrenetetrasulfonic acid sodium salt Fluorescent substance concentration: Adjusted so that the concentration in the circulating cooling water is 120 μg/L Light shielding member: Commercially available cheese joint for PVC pipes

In Example 3, the excitation light emitting part / The angle formed by the fluorescence receiving unit 40 and the still water surface of the lower water tank was rotated within the range of 0° to 180°. The results are shown in FIG.

At 0°, bubbles accumulated in the fluorescence receiving part of the measuring part 46, and accurate measurement was impossible. Between 30° and 180°, by attaching the light shielding member 50, the light of the same wavelength as the fluorescence of the fluorescent substance contained in the artificial sunlight is blocked, thereby suppressing the light entering the fluorescence light receiving section. It is considered that the measured value is stable because the decrease in relative intensity due to outside light can be suppressed (see FIG. 15).

[Experiment 4 (verification of cleaning effect)]
The cleaning effect was verified under the following conditions.

<Example 4>
Raw water: Sagamihara city water (add bouillon once a day)
Apparatus: Open circulation cooling tower simulator (Fig. 16)
Fluorometer: Pixis ST-500
Fluorescent substance: 1,3,6,8-pyrenetetrasulfonic acid sodium salt Fluorescent substance concentration: Adjusted so that the concentration in the circulating cooling water is 100 μg/L Viable bacteria measurement: Sanai Biochecker TTC
Cleaning function: jet cleaning Cleaning interval: once a day

As in Example 3 and Comparative Example 3, showering was performed in the open circulation cooling tower simulator to generate air bubbles in the water tank 52 . Further, in the same manner as in Example 3 and Comparative Example 3, sunlight was artificially generated and irradiated. Artificial sunlight was applied for 12 hours and turned off for 12 hours.

In addition, two sets of the same measurement unit 46 of the fluorescence photometer were prepared and immersed in the water tank 52 of the open circulation cooling tower simulator. One of the immersed measurement parts 46 was equipped with a cleaning function. The other measurement unit 46 was not equipped with a cleaning function. As a cleaning function, air was supplied through an air supply pipe 66 so as to hit the surface of the fluorescence light receiving part of the measurement part 46 . Calculation of the measurement error was performed using Equation 1 above. FIG. 17 shows the bacterial logarithm (CFU/mL) and the measurement error (%) with respect to the operation time (hr) in Example 4.

In this way, the measurement error could be suppressed by installing the cleaning function.

As described above, in the example, the fluorescent substance concentration in the circulating cooling water of the cooling tower could be measured with high accuracy without being affected by temperature, external light, and air bubbles.

1 cooling tower, 3 measuring device, 10 lower water tank, 12 fan, 14 sprinkler tank, 16 filler, 18 cross plate, 20 fluorometer, 22, 54 circulation pump, 24 heat exchanger, 26 chemical tank, 28 chemical pump, 30, 60 circulation pipe, 32 chemical solution pipe, 34 receiving part, 36 calculation part, 38 control part, 40 excitation light emitting part/fluorescence receiving part, 40a excitation light emitting part, 40b fluorescence receiving part, 42 excitation light source, 44 light receiving element , 46 measurement unit, 50 light shielding member, 52 water tank, 56 tubular member, 58 data logger, 62 artificial sunlight light source, 64 sprinkler pipe, 66 air supply pipe.

Claims (6)

A water treatment chemical measuring device for measuring the concentration of a water treatment chemical in circulating cooling water of a cooling tower,
adding means for adding a water treatment chemical and a fluorescent substance as a tracer substance to the circulating cooling water;
a fluorescence photometer that has a measurement unit that includes a fluorescence light receiving unit and optically measures the fluorescence of the fluorescent substance present in the circulating cooling water;
with
At least the fluorescence light receiving unit of the measurement unit is immersed in a lower water tank storing the circulating cooling water in the cooling tower,
A measuring apparatus for water treatment chemicals, wherein the cooling tower is shielded so as to prevent external light entering from outside the cooling tower from entering the fluorescent light receiving portion of the fluorescence photometer. The water treatment chemical measuring device according to claim 1,
A measuring apparatus for water treatment chemicals, wherein the fluorescence photometer has a cleaning function for cleaning the fluorescence receiving part. The water treatment chemical measuring device according to claim 1 or 2,
A water treatment chemical measuring apparatus, wherein the concentration of the water treatment chemical in the circulating cooling water is controlled based on the measured value of the fluorescence photometer. A method for measuring a water treatment chemical for measuring the concentration of a water treatment chemical in circulating cooling water of a cooling tower, comprising:
an addition step of adding a water treatment chemical and a fluorescent substance as a tracer substance to the circulating cooling water;
a fluorescence measurement step of optically measuring the fluorescence of the fluorescent substance present in the circulating cooling water with a fluorescence photometer having a measurement unit including a fluorescence light receiving unit;
including
At least the fluorescence light receiving unit of the measurement unit is immersed in a lower water tank storing the circulating cooling water in the cooling tower,
A method for measuring a water treatment chemical, wherein the cooling tower is shielded so as to prevent external light entering from outside the cooling tower from entering the fluorescent light receiving portion of the fluorescence photometer. A method for measuring a water treatment chemical according to claim 4,
A method for measuring water treatment chemicals, wherein the fluorescence photometer has a cleaning function for cleaning the fluorescence receiving part. A method for measuring a water treatment chemical according to claim 4 or 5,
A method for measuring a water treatment chemical, comprising controlling the concentration of the water treatment chemical in the circulating cooling water based on the measured value of the fluorometer.

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