Measurement device and method for measuring water treatment chemicals.

Abstract

To provide a water treatment chemicals measurement device and measurement method with which a fluorescent substance concentration in the circulating cooling water of a cooling tower is hardly affected by the temperature, external light and air bubbles and can be measured with good accuracy.SOLUTION: Provided is a water treatment chemicals measurement device 3 for measuring the concentration of a water treatment chemical in the circulating cooling water of a cooling tower 1, said measurement device 3 comprising addition means for adding a water treatment chemical and a fluorescent substance as a tracer substance to the circulating cooling water, and a fluorophotometer 20 for optically measuring the fluorescence of the fluorescent substance existing in the circulating cooling water and having a measurement unit 46 that includes a fluorescence receiving unit. At least the fluorescence receiving unit of the measurement unit 46 is immersed in a lower water tank 10 of the cooling tower 1 that stores the circulating cooling water, with external light entering from the outside of the cooling tower 1 shielded so as to suppress from entering the fluorescence receiving unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a measuring device and a measuring method for a water treatment chemical for measuring the concentration of a water treatment chemical in the circulating cooling water of a cooling tower.

Background Art

[0002] As is well known, in all industries, water such as industrial water plays an important role and is often used in a circulating water system. Examples of the circulating water systems that are frequently used include a boiler water system, an open or closed cooling water system, and the like.

[0003] For the water quality management of these circulating water systems, various sensors are used. In a cooling tower, these sensors are installed in the water tank at the lower part of the cooling tower for water quality measurement.

[0004] In addition, for the water treatment of these circulating water systems, various water treatment chemicals (agents) are used to suppress water-related problems such as corrosion, scale, and slime. In order to maintain the effects of these water treatment chemicals, it is necessary to accurately grasp the concentrations of these chemicals at any position, time, etc., and perform appropriate concentration management. In addition, as a concentration management method when using a chemical that cannot or is difficult to measure its own concentration as a water treatment chemical, a substance that can be easily measured for concentration is used as a tracer.

[0005] In Patent Document 1, a conductivity meter and an oxidation-reduction potential meter are used as sensors installed in the lower water tank of a cooling tower.

[0006] As a tracer substance, a method using a sulfonated pyrene compound, which is a fluorescent substance, has been proposed. For example, in Patent Documents 2 and 3, as a method for measuring this sulfonated pyrene compound, a method of installing a fluorophotometer in the flow path of a circulating water system and using it has been proposed.

[0007] Another method using lithium as a tracer material involves immersing a lithium ion electrode vertically in the lower water tank of a cooling tower as a method for measuring lithium. Furthermore, Patent Document 4 describes covering the lithium ion-sensitive membrane with a light-shielding cover to suppress the adhesion of biofilms to the lithium ion-sensitive membrane.

[0008] Patent Document 5 proposes a method for installing a sensor in which the detection surface of the dissolved oxygen electrode is oriented in the same direction as the rising direction of bubbles in the aeration tank. This method dictates that because the detection surface is oriented vertically, there is no bubble stagnation, and therefore stable and accurate water quality measurements can be taken.

[0009] In Patent Document 1, as shown in Figure 2, a pH meter, conductivity meter, and oxidation-reduction potential meter are installed in the lower water tank of the cooling tower, but these are not fluorophotometers. In Patent Document 4, a sensor that measures optically using a lithium-ion functional membrane is installed in the lower water tank of the cooling tower, but it utilizes ion optodes and is not a fluorophotometer that optically measures the fluorescence of fluorescent substances present in the water being treated.

[0010] Patent Document 2 describes the use of a fluorometer inserted into a pipe that serves as a flow path for a circulating water system. However, this method had the following problems. (1) When there is a difference between the water temperature and the ambient temperature, temperature drift occurs, making accurate measurement impossible. (2) When transparent piping was used, external light could enter, and optical influences sometimes prevented accurate measurements. (3) When transparent piping is used, restrictions are placed on the installation locations in order to prevent external light from entering. (4) When the tee fitting was installed horizontally, air pockets would form, making accurate measurements impossible. (5) There were restrictions on the direction in which the tee fitting could be installed, and in some cases it was difficult to install depending on the surrounding conditions. (6) During maintenance and calibration, it was necessary to remove the fluorometer from the piping, which made the work complicated and there was a possibility that the treated water would leak out of the system.

[0011] Patent Document 3 describes a method for automatically sampling water to be treated and measuring it with a fluorometer in the flow path. However, this method had the following problems in addition to the same problems as (2), (3), and (6) above. (7) There was a time lag between sampling and fluorescence measurement, during which the water temperature changed, making accurate measurement impossible.

[0012] Patent Document 5 describes a method for suppressing bubble stagnation by installing a dissolved oxygen electrode so that the detection surface is aligned with the specific direction of bubble movement (upward direction) in the aeration tank. However, unlike the aeration tank, the lower water tank of a cooling tower is not aerated. Since water is sprayed from the top of the cooling tower, the bubbles in the lower water tank of the cooling tower are swirled around, and many of them do not have a specific movement. Therefore, when this method is applied to the lower water tank of a cooling tower, the following problems arise. (8) The orientation of the detection surface could not be determined, making it difficult to install.

[0013] Patent Document 4 describes covering a lithium-ion-sensitive membrane with a light-shielding cover to suppress the adhesion of biofilms to the lithium-ion-sensitive membrane. However, this method had the following problems. (9) Once a biofilm has attached, it is difficult to remove it. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] Japanese Patent Publication No. 2006-098003 [Patent Document 2] U.S. Patent No. 7,099,012 [Patent Document 3] Special Publication No. 2003-532049

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0015] An object of the present invention is to provide a measuring apparatus and a measuring method for a water treatment chemical that can accurately measure the concentration of a fluorescent substance in the circulating cooling water of a cooling tower without being easily affected by temperature, external light, and bubbles.

Means for Solving the Problems

[0016] The present invention is a measuring apparatus for a water treatment chemical that measures the concentration of a water treatment chemical in the circulating cooling water of a cooling tower, comprising: an adding means for adding a water treatment chemical and a fluorescent substance as a tracer substance to the circulating cooling water; a measuring unit including a fluorescence light receiving unit that optically measures the fluorescence of the fluorescent substance present in the circulating cooling water; and a fluorometer. At least the fluorescence light receiving unit of the measuring unit is immersed in a lower water tank that stores the circulating cooling water in the cooling tower at a location where the flow velocity of the circulating cooling water in the operating cooling tower is 0.001 m / s or more, and is shielded from light so as to suppress external light entering from outside the cooling tower from entering the fluorescence light receiving unit of the fluorometer. flow rate It is a measuring apparatus for a water treatment chemical.

[0017] In the measuring apparatus for the water treatment chemical, it is preferable that the fluorometer has a cleaning function for cleaning the fluorescence light receiving unit.

[0018] In the measuring apparatus for the water treatment chemical, it is preferable to perform concentration management of the water treatment chemical in the circulating cooling water based on the measured value of the fluorometer.

[0019] The present invention relates to a method for measuring the concentration of a water treatment chemical in the circulating cooling water of a cooling tower, the method including: an addition step of adding a water treatment chemical and a fluorescent substance as a tracer substance into the circulating cooling water; a fluorescence measurement step of optically measuring the fluorescence of the fluorescent substance present in the circulating cooling water by a fluorometer having a measurement unit including a fluorescence light receiving unit; and at least the fluorescence light receiving unit of the measurement unit is immersed in a lower water tank that stores the circulating cooling water in the cooling tower at a location where the flow rate flow rate of the circulating cooling water in the operating cooling tower is 0.001 m / s or more, and is shielded from light so as to suppress external light entering from outside the cooling tower from entering the fluorescence light receiving unit of the fluorometer.

[0020] In the method for measuring the water treatment chemical, it is preferable that the fluorometer has a cleaning function for cleaning the fluorescence light receiving unit.

[0021] In the method for measuring the water treatment chemical, it is preferable to perform concentration management of the water treatment chemical in the circulating cooling water based on the measurement value of the fluorometer.

Advantages of the Invention

[0022] According to the present invention, it is possible to provide a measuring device and a measuring method for a water treatment chemical that can accurately measure the fluorescence substance concentration in the circulating cooling water of a cooling tower without being easily affected by temperature, external light, and bubbles.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a schematic configuration diagram showing an example of a cooling tower provided with a measuring device for a water treatment chemical according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic configuration diagram showing an example of a measurement unit of a fluorometer in a measuring device for a water treatment chemical according to an embodiment of the present invention. [Figure 3] FIG. 3 is a schematic configuration diagram ((a): side view, (b): plan view) showing another example of a measurement unit of a fluorometer in a measuring device for a water treatment chemical according to an embodiment of the present invention. [Figure 4] This is a schematic diagram ((a): side view, (b): top view) showing another example of the measuring section of a fluorescence photometer in a measuring device for water treatment chemicals according to an embodiment of the present invention. [Figure 5] This is a schematic diagram showing an example of an immersion method for the measuring section of a fluorescence photometer in a measuring device for water treatment chemicals according to an embodiment of the present invention. [Figure 6] This is a schematic diagram showing an example of a light-shielding member to be attached to the measuring section of a fluorescence photometer in a measuring device for water treatment chemicals according to an embodiment of the present invention. [Figure 7] This is a schematic diagram showing the open-circulation cooling tower simulation device used in Example 1 and Comparative Example 1. [Figure 8] This graph shows the water temperature (°C) and measurement error (%) as a percentage of the operating time (hr) in Example 1 and Comparative Example 1. [Figure 9] This is a schematic diagram showing the open-circulation cooling tower simulation device used in Example 2 and Comparative Example 2. [Figure 10] This graph shows the water temperature (°C) and measurement error (%) as a percentage of the operating time (hr) in Example 2 and Comparative Example 2. [Figure 11] This is a schematic diagram showing the open-circulation cooling tower simulation device used in Comparative Example 3. [Figure 12] This is a schematic diagram showing the open-circulation cooling tower simulation device used in Example 3. [Figure 13] This graph shows the measured value of PTSA (μg / L) as a function of the rotation angle (°) of the fluorometer in Comparative Example 3 and Example 3. [Figure 14] This is a schematic diagram showing how light enters the fluorescence light receiving section of the fluorometer in Comparative Example 3. [Figure 15] This is a schematic diagram showing how light enters the fluorescence light receiving section of the fluorophotometer in Example 3. [Figure 16] This is a schematic diagram showing the open-circulation cooling tower simulation device used in Example 4. [Figure 17] This graph shows the bacterial count (CFU / mL) and measurement error (%) as a percentage of the operating time (hr) in Example 4. [Modes for carrying out the invention]

[0024] Embodiments of the present invention will be described below. This embodiment is just one example of how the present invention can be implemented, and the present invention is not limited to this embodiment.

[0025] Figure 1 shows a schematic diagram of an example of a cooling tower equipped with a water treatment chemical measuring device according to an embodiment of the present invention, and its configuration will be described below.

[0026] The cooling tower 1 shown in Figure 1 is, for example, a cooling tower of an open-circulation cooling water system that cools circulating cooling water by bringing it into contact with outside air. The cooling tower 1 is equipped with a lower water tank 10 at the bottom, a fan 12 at the top for taking outside air into the interior of the cooling tower 1, packing material 16 on the outer circumference of the tower, and a water spraying tank 14 above the packing material 16. A connecting plate 18, which is a plate-shaped member, may be installed parallel to the water surface of the lower water tank 10 at a predetermined distance above the water surface. For example, the lower side of the lower water tank 10 and the water spraying tank 14 are connected by circulation piping 30 via a circulation pump 22 and a heat exchanger 24.

[0027] The water treatment chemical measuring device 3 is a device that measures the concentration of water treatment chemicals 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 chemical piping 32 as means for adding water treatment chemicals and a fluorescent substance as a tracer substance to the circulating cooling water, and has a measuring unit 46 including a fluorescent light receiving unit, and includes a fluorophotometer 20 that optically measures the fluorescence of the fluorescent substance present in the circulating cooling water.

[0028] The structure of the fluorophotometer 20 includes, for example, an excitation light source, a fluorescent substance and an optical filter for selecting a specific excitation wavelength to match the fluorescence properties of the fluorescent substance, an excitation light emission unit for emitting excitation light outside the fluorophotometer, a fluorescence light receiving unit for allowing the fluorescence of the fluorescent substance present in the water to be treated (in this case, circulating cooling water) to enter the fluorophotometer, an optical filter for selecting a specific fluorescence wavelength, a light receiving element having the function of converting the fluorescence state into an electrical signal, and a measurement unit 46; and a calculation unit 36 ​​that receives the electrical signal and calculates the concentration of water treatment chemicals. The fluorophotometer 20 may also include a receiving unit 34 that receives a signal input from the light receiving element of the measurement unit 46, and a control unit 38 that determines the amount of water treatment chemicals to be added to the water to be treated.

[0029] The fluorescence photometer 20, for example as shown in Figure 2, has an excitation light emission unit / fluorescence receiving unit 40 on one end surface of a cylindrical or other shaped measuring unit 46, and further comprises an excitation light source 42 and a light receiving element 44. The excitation light emitted from the excitation light source 42 is transmitted through the excitation light emission unit / fluorescence receiving unit 40 and emitted, and after the object to be measured absorbs the excitation light, it emits fluorescence, and the fluorescence transmitted through the excitation light emission unit / fluorescence receiving unit 40 can be received by the light receiving element 44. The emission surface / light receiving surface of the excitation light emission unit / fluorescence receiving unit 40 is flat.

[0030] Another structure of the fluorophotometer 20, as shown in Figure 3, may be one in which the emission surface / receiving surface of the excitation light emission unit / fluorescence receiving unit 40 is curved and provided inside one end of the hollow cylindrical shape of the measuring unit 46. The excitation light emitted from the excitation light source 42 is transmitted through, for example, the curved excitation light emission unit / fluorescence receiving unit 40 and emitted, and the object to be measured, passing through the curved excitation light emission unit / fluorescence receiving unit 40, absorbs the excitation light and emits fluorescence, and the fluorescence transmitted through the curved excitation light emission unit / fluorescence receiving unit 40 can be received by the photodetector 44. The angle between the excitation light source 42 and the photodetector 44 is not particularly limited.

[0031] As an alternative structure for the fluorophotometer 20, as shown in Figure 4, the excitation light emission unit / fluorescence receiving unit may be separated into an excitation light emission unit 40a and a fluorescence receiving unit 40b on the surface or inside of one end of a cylindrical or other measuring unit 46, and arranged, for example, in an L-shape. The configuration allows excitation light emitted from the excitation light source 42 to pass through the excitation light emission unit 40a and be emitted, the object to be measured to absorb the excitation light and emit fluorescence, and the fluorescence transmitted through the fluorescence receiving unit 40b to be received by the photodetector 44. The angle between the excitation light emission unit 40a and the fluorescence receiving unit 40b is not particularly limited. The angle between the excitation light source 42 and the photodetector 44 is not particularly limited.

[0032] As shown in Figure 1, the measuring unit 46 of the fluorophotometer 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 emission unit / fluorescence receiving unit of the measuring unit 46 is immersed in the lower water tank 10. Furthermore, as will be described later, the unit is shielded to suppress external light entering from outside the cooling tower 1 from entering the fluorescence receiving unit of the measuring unit 46.

[0033] Here, "external light" refers to light that enters the cooling tower from the outside through direct light, reflection, scattering, or transmission. Examples of external light include sunlight, direct light emitted from fluorescent lamps, LED lamps, mercury lamps, halogen lamps, etc., as well as light that has been reflected, scattered, or transmitted by the environment outside the cooling tower, and combinations thereof.

[0034] The chemical outlet on the lower side of the chemical tank 26 and the chemical inlet on the upper side of the lower water tank 10 of the cooling tower 1 are connected by chemical piping 32 via a chemical pump 28.

[0035] The water treatment chemical measuring device 3 comprises a receiving unit 34, a calculation unit 36, and a control unit 38. The receiving unit 34 and the measuring unit 46 are connected to each other via wired or wireless electrical connection or the like. The control unit 38 and the chemical pump 28 are connected to each other via wired or wireless electrical connection or the like.

[0036] The operation of the cooling tower 1 and the water treatment chemical measuring device 3 will be described.

[0037] In the cooling tower 1, the circulating cooling water stored in the lower water tank 10 of the cooling tower 1 is sent from the circulating cooling water outlet through piping 30 by the circulation pump 22 to the heat exchanger 24. In the heat exchanger 24, it exchanges heat with a high-temperature, high-pressure refrigerant, becoming cooling water with a higher temperature, which is then sent from the heat exchanger 24 through piping 30 to the spray tank 14 at the top of the cooling tower 1. The cooling water stored in the spray tank 14 is sprayed into the packing material 16 from the top of the cooling tower 1. The sprayed circulating cooling water comes into contact with air taken in from the outside by the fan 12 within the packing material 16, and a portion of it evaporates, releasing latent heat of vaporization, which lowers the temperature of the cooling water, causing it to fall back into the lower water tank 10 of the cooling tower 1 and be stored there. The circulating cooling water stored in the lower water tank 10 is sent to the heat exchanger 24 through piping 30 by the circulation pump 22 as described above. In this way, the circulating cooling water is circulated.

[0038] Meanwhile, water treatment chemicals stored in the chemical tank 26 and a fluorescent substance as a tracer substance are added by the chemical pump 28 through the chemical piping 32 to the circulating cooling water stored in the lower water tank 10 of the cooling tower 1 (addition step). The fluorescence of the fluorescent substance present in the circulating cooling water is optically measured by a fluorophotometer 20 having a measuring unit 46 in which at least a fluorescence light receiving unit is immersed in the lower water tank 10 of the cooling tower 1 (fluorescence measurement step). Specifically, excitation light emitted from the excitation light source 42 of the measuring unit 46 shown in Figures 2-4 is transmitted through the excitation light emitter / fluorescence light receiving unit 40 or the excitation light emitter 40a and emitted, the object to be measured absorbs the excitation light and emits fluorescence, and the fluorescence transmitted through the excitation light emitter / fluorescence light receiving unit 40 or the fluorescence light receiving unit 40b is received by the photodetector 44.

[0039] The receiving unit 34 receives a signal input from the light-receiving element 44 of the measuring unit 46 (receiving step). The calculation unit 36 ​​receives the signal received by the receiving unit 34 and, for example, converts the concentration of the fluorescent substance contained in the circulating cooling water using a calibration curve that has been stored in advance. If the ratio of the amount of water treatment chemicals added to the amount of fluorescent substance added to the water system is known in advance as a coefficient (chemical concentration conversion coefficient due to fluorescent substance), the calculation unit 36 ​​calculates the concentration of the water treatment chemicals by multiplying the concentration of the fluorescent substance by the coefficient. Alternatively, the concentration of the water treatment chemicals contained in the circulating cooling water may be converted using another calibration curve that has been stored in advance (calculation step). The control unit 38 calculates the required amount of water treatment chemicals to be added based on the concentration of water treatment chemicals calculated by the calculation unit 36. The control unit 38 may control the drive of the chemical pump 28 via the control line based on the calculated amount of water treatment chemicals to be added (control step).

[0040] In this way, the concentration of the tracer substance, a fluorescent substance, in the circulating cooling water is measured, thereby determining the concentration of the water treatment chemical in the circulating cooling water. Based on the concentration of the water treatment chemical in the circulating cooling water measured by the fluorophotometer, the concentration of the water treatment chemical in the circulating cooling water can be controlled, and the necessary amount of water treatment chemical may be added.

[0041] The measuring device and measuring method for water treatment chemicals according to this embodiment can accurately measure the concentration of fluorescent substances in the circulating cooling water of the cooling tower 1, with less influence from temperature, ambient light, and bubbles.

[0042] By immersing at least the excitation light emission unit / fluorescence receiving unit 40 of the measuring unit 46 of the fluorophotometer 20 in the lower water tank 10 of the cooling tower 1, exposure of the measuring unit 46 to ambient temperature is suppressed, and temperature drift can be eliminated (elimination of (1) above). In addition, sampling of the circulating cooling water is not required, the time loss until measurement can be reduced, and changes in water temperature during measurement can be suppressed (elimination of (7) above). Since the flow of bubbles in the lower water tank 10 is not uniform, bubble accumulation is less likely to occur, and accurate measurements can be made (elimination of (4) above). The direction of the detection surface of the measuring unit 46 (excitation light emission unit / fluorescence receiving unit 40 or fluorescence receiving unit 40b) can be arbitrarily determined within the lower water tank 10, and there are almost no restrictions on installation (elimination of (3), (5), and (8) above). The measuring unit 46 can be easily removed from the lower water tank 10, making the work easier, and there is almost no leakage of circulating cooling water outside the system (elimination of (6) above).

[0043] Furthermore, as will be described later, the excitation light emission section / fluorescence light receiving section 40 of the measurement section 46 is shielded from light, which reduces optical influences and enables accurate measurements (elimination of (2) above).

[0044] In the water treatment chemical measuring apparatus and measuring method according to this embodiment, since biofilms and the like adhering to the surface of the excitation light emission unit / fluorescence receiving unit 40 may affect the measurement accuracy, the fluorophotometer 20 may have a cleaning function to clean the excitation light emission unit / fluorescence receiving unit 40 of the measuring unit 46. By providing a cleaning function to clean the surface of the excitation light emission unit / fluorescence receiving unit 40, the measurement accuracy can be greatly improved. The cleaning function can be any configuration that can clean the surface of the excitation light emission unit / fluorescence receiving unit 40 of the measuring unit 46, and there are no particular restrictions, but for example, a configuration can be provided in which a wiper made of rubber or the like or a jet (pulse) sprayer that sprays gas such as air is provided to clean the excitation light emission unit / fluorescence receiving unit 40 of the measuring unit 46. By providing a cleaning function such as a wiper or jet (pulse) sprayer, biofilms that have adhered to the excitation light emission unit / fluorescence receiving unit 40 can be easily removed (solving the problem in (9) above).

[0045] In the water treatment chemical measuring device and measuring method according to this embodiment, as described above, the concentration of water treatment chemicals in circulating cooling water can be controlled based on the measurement value of the fluorescence photometer 20. Accurate concentration control can be performed by obtaining accurate measurement values ​​with almost no time loss.

[0046] The excitation light source 42 is a light source that emits light within a selected wavelength range.

[0047] An optical filter for selecting a specific excitation wavelength may be installed, for example, between the excitation light source 42 and the excitation light emitter / fluorescence receiver 40. This optical filter has the function of transmitting a predetermined wavelength from the excitation light source 42.

[0048] The excitation light emission section or excitation light emission section 40a in the excitation light emission section / fluorescence light receiving section 40 only needs to transmit excitation light and is made of, for example, glass or plastic.

[0049] The fluorescence receiver or fluorescence receiver 40b in the excitation light emission unit / fluorescence receiver 40 only needs to transmit fluorescence and can be made of, for example, glass or plastic.

[0050] The angle of the excitation light emission unit / fluorescence light receiving unit 40 may be set at any angle.

[0051] An optical filter for selecting a specific fluorescence wavelength may be installed, for example, between the excitation light emission unit / fluorescence receiving unit 40 and the photodetector 44. This optical filter has the function of transmitting a predetermined wavelength from the fluorescence.

[0052] The light-receiving element 44 is a component that has the function of converting fluorescence into an electrical signal, and has the function of converting it into an analog signal or a digital signal and outputting it. A photodiode, phototransistor, photomultiplier tube, etc. may be used as the light-receiving element 44.

[0053] The receiving unit 34 has the function of receiving signals input from the light-receiving element 44 of the measuring unit 46.

[0054] The calculation unit 36 ​​has the function of converting the signal received by the receiving unit 34 into the concentration of fluorescent substances contained in the circulating cooling water, for example, using a calibration curve that has been stored in advance.

[0055] The control unit 38 has the function of calculating the amount of water treatment chemicals to be added using the fluorescent substance concentration calculated by the calculation unit 36, and controlling the drive of the chemical pump 28 and the like via the control line.

[0056] The arithmetic unit 36 ​​may be one in which the receiving unit 34 can be considered separately, or it may be one in which the receiving unit 34 cannot be considered separately, that is, one that includes the receiving unit 34.

[0057] The receiving unit 34, the calculation unit 36, and the control unit 38, or the calculation unit 36 ​​and the control unit 38, may be the same unit device, and the use of a programmable controller or computer is preferred.

[0058] As a method for calculating the concentration of fluorescent substances, if the relationship between the concentration of fluorescent substances and the electrical signal of the fluorophotometer 20 (e.g., a calibration curve) is known in advance, then, for example, the concentration of fluorescent substances in the treated water (in this case, circulating cooling water) can be detected at an appropriate sampling location and time.

[0059] One method for calculating the concentration of water treatment chemicals is to first determine the ratio of the amount of water treatment chemicals added to the amount of fluorescent substance added to the water system as a known coefficient (conversion coefficient for chemical concentration using fluorescent substance). Then, for example, by detecting the concentration of the fluorescent substance in the water to be treated (in this case, circulating cooling water) at an appropriate sampling location and time, and multiplying that value by the coefficient, the concentration of the water treatment chemicals can be calculated. Based on this calculated value, the amount of water treatment chemicals and fluorescent substance to be added to the circulating cooling water can be determined.

[0060] The water treatment chemical measuring device 3 may optionally include at least one of the following sensors: a sensor for measuring temperature, a sensor for measuring pH, a sensor for measuring electrical conductivity, a sensor for measuring chloride ions, a sensor for measuring sulfate ions, a sensor for measuring the consumption of at least one of acids and alkalis, a sensor for measuring hardness, a sensor for measuring silica, a sensor for measuring iron, a sensor for measuring copper, a sensor for measuring ammonium ions, a sensor for measuring carbon dioxide, a sensor for measuring oxidation-reduction potential (ORP), a sensor for measuring oxidizing agents, a sensor for measuring corrosion, a sensor for measuring scale, or a sensor for measuring slime.

[0061] Examples of fluorescent substances include sulfonated pyrene compounds (such as sodium 1,3,6,8-pyrenetetrasulfonate), uranine, fluorescein, phycoerythrin, phycocyanin, and rhodamine. Any fluorescent substance can be a chemical that absorbs a specific wavelength and emits fluorescence at a different wavelength; there are no particular restrictions.

[0062] For fluorescent substances in circulating cooling water, extremely small concentrations in the range of 0.1 to 10,000 μg / L (ppb) are sufficient for them to function as tracers, so this concentration range is acceptable. Within this concentration range, calibration curves for fluorescent substance concentrations usually have sufficient reproducibility. Below 0.1 μg / L, the light-receiving sensitivity may be insufficient, so from an economic standpoint, the concentration of fluorescent substances in circulating cooling water should be between 0.1 and 10,000 μg / L.

[0063] The installation location for the measuring unit 46 of the fluorophotometer 20 is such that at least the excitation light emission unit / fluorescence receiving unit 40 of the measuring unit 46 is immersed in the lower water tank 10 of the cooling tower 1. It is preferable that the entire measuring unit 46 is immersed in the lower water tank 10 of the cooling tower 1.

[0064] Regarding the immersion point in the lower water tank 10 of the cooling tower 1, it is sufficient that at least the excitation light emission part / fluorescence light receiving part 40 of the measurement unit 46 is immersed below the water surface in the lower water tank 10, preferably in a location where the circulating cooling water in the operating cooling tower 1 is not stationary, and more preferably in the circulating cooling water in the operating cooling tower 1 flow rate It is best to immerse the material in areas where the current is 0.001 m / s or higher.

[0065] The emission surface / receiving surface of the excitation light emission unit / fluorescence receiving unit 40, the emission surface of the excitation light emission unit 40a, or the receiving surface of the fluorescence receiving unit 40b of the measuring unit 46, which is immersed in the lower water tank 10 of the cooling tower 1, may be angled, for example, as shown in Figure 5. By angling the emission surface / receiving surface of the excitation light emission unit / fluorescence receiving unit 40, the emission surface of the excitation light emission unit 40a, or the receiving surface of the fluorescence receiving unit 40b, the accumulation of bubbles becomes less likely. For example, when the cylindrical measuring section 46 is rotated around its center as an axis, the angle between the emission surface / receiving surface of the excitation light emission section / fluorescence light receiving section 40, the emission surface of the excitation light emission section 40a, or the receiving surface of the fluorescence light receiving section 40b and the still water surface of the lower tank is, with the axis of the measuring section 46 being 90° when it is horizontal, preferably in the range of 0° to 180°, greater than 0° and 180° or less, and more preferably in the range of 30° to 180°. When the axis of the measuring section 46 is horizontal, the angle between the emission surface / receiving surface of the excitation light emission section / fluorescence light receiving section 40, the emission surface of the excitation light emission section 40a, or the receiving surface of the fluorescence light receiving section 40b and the still water surface of the lower tank is, for example, in the range of 0° to 180°, preferably greater than 0° and 180° or less, and more preferably in the range of 30° to 180°. Note that when using the fluorescence photometer 20 shown in Figure 4, it is preferable that the angle range described above is with respect to the receiving surface of the fluorescence light receiving section 40b rather than the emission surface of the excitation light emission section 40a.

[0066] Here, a still water surface refers to a water surface without waves. In the lower water tank 10 of the cooling tower 1, waves may form on the water surface when water is sprayed from the top of the cooling tower 1, when wind flows into the cooling tower 1 from outside, or when vibrations from outside the cooling tower 1 are transmitted to the lower water tank 10 of the cooling tower 1. Therefore, a still water surface in the lower water tank 10 refers to a water surface without waves when water is not sprayed from the top of the cooling tower 1, when wind does not flow into the cooling tower 1 from outside, or when vibrations from outside the cooling tower 1 are not transmitted to the lower water tank 10 of the cooling tower 1.

[0067] As for the method of shielding the excitation light emission unit / fluorescence receiving unit 40 of the measurement unit 46, any method that suppresses direct sunlight entering the inside of the cooling tower 1, as well as reflected and scattered sunlight from the inside of the cooling tower 1, from entering the excitation light emission unit / fluorescence receiving unit 40 is acceptable. For example, as shown in Figure 1, the excitation light emission unit / fluorescence receiving unit 40 may be positioned below the gangway plate 18 or below the packing material 16. To further improve the shielding performance against ambient light, direct sunlight, reflected light, scattered light, etc., a dedicated light-shielding member may be attached to the measurement unit 46.

[0068] For example, as shown in Figure 6, the dedicated light-shielding member 50 may have a structure that covers only the excitation light emission unit / fluorescence light receiving unit 40, or it may have a structure that covers the entire measurement unit 46. The light-shielding member 50 has a structure that prevents ambient light, direct light, reflected light and scattered light from inside the cooling tower from directly entering the excitation light emission unit / fluorescence light receiving unit 40, and it is not particularly limited as long as it has a structure that allows circulating cooling water to flow through it, for example, by having flow holes. The light-shielding member 50 may have a multilayer structure in which two or more cylindrical bodies are arranged in multiple layers, with an insertion hole formed at one end of each cylindrical body for inserting the measurement unit 46, the other end of at least one cylindrical body being sealed, and flow holes formed on the side of each cylindrical body for passing circulating cooling water, with at least a part of the flow hole of the outermost cylindrical body being blocked by the side of another cylindrical body, or a commercially available PVC pipe tee fitting may be used. The material of the light-shielding member 50 is not particularly limited, as long as it does not adversely affect either the fluorophotometer 20 or the circulating cooling water system as much as possible and is durable in circulating cooling water. For example, plastics or metals colored black or the like can be used as the material of the light-shielding member 50. [Examples]

[0069] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0070] [Experiment 1 (Test to confirm the effects of immersion in the sensor)] <Example 1, Comparative Example 1> A test was conducted to confirm the effects of immersion when the measuring section of a fluorometer was submerged under the following conditions.

[0071] (Experimental conditions) Raw water: Sagamihara City water Equipment: Open-circulation cooling tower simulation device (Figure 7) Fluorescence photometer: Little Dipper 2 manufactured by Turner Design (measurement unit configuration as shown in Figure 2) Stationary Fluorescent Photometer: Shimadzu RF-5300PC Fluorescent substance: 1,3,6,8-Sodium pyrenetetrasulfonate Fluorescent substance concentration: Adjusted so that the concentration in the circulating cooling water is 70 μg / L.

[0072] As shown in Figure 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 piping 60 via a circulation pump 54. Two identical units of the fluorescence photometer's measurement unit 46 were prepared. One was completely immersed in the water tank 52 of the open circulation cooling tower simulation device (Example 1), and the other was inserted into a T-shaped tubular member 56 installed in the middle of the circulation piping 60 (Comparative Example 1). Each measurement unit 46 was electrically connected to the data logger 58 for communication. The measurement unit 46 immersed in the water tank 52 was positioned so that the angle between the excitation light emission unit / fluorescence receiving unit 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 entire unit from light.

[0073] The fluorescence of the circulating cooling water was measured using each of the two measuring units 46. Additionally, the fluorescence of the circulating cooling water was measured using a stationary fluorometer. The measurement error was calculated using the following equation 1. A value closer to 0% indicates a more accurate measurement.

[0074] Error [%] = (Measurement value from fluorescent photometer - Measurement value from stationary fluorescent photometer) / (Measurement value from stationary fluorescent photometer) Equation 1

[0075] Figure 8 shows the relationship between water temperature (°C) and measurement error (%) as a percentage of operating time (hr). The measurement error was smaller when the fluorescent photometer's measuring unit 46 was immersed in the water tank 52 compared to when it was inserted into the circulation pipe 60. This is thought to be because immersing the fluorescent photometer's measuring unit 46 in the water tank 52 eliminated the temperature difference between the water temperature and the ambient temperature.

[0076] [Experiment 2 (Test to confirm the effect when a part of the sensor is immersed)] <Example 2, Comparative Example 2> A test was conducted to confirm the effects of immersion when the measuring section of a fluorometer was submerged under the following conditions.

[0077] (Experimental conditions) Raw water: Sagamihara City water Equipment: Simulated open-circulation cooling tower (Figure 9) Fluorescence photometer: Turner Design Little Dipper 2 Stationary Fluorescent Photometer: Shimadzu RF-5300PC Fluorescent substance: 1,3,6,8-Sodium pyrenetetrasulfonate Fluorescent substance concentration: Adjusted so that the concentration in the circulating cooling water is 70 μg / L.

[0078] As shown in Figure 9, two identical units of the fluorophotometer's measurement unit 46 were prepared. One unit was partially immersed (excitation light emission unit / fluorescence receiving unit 40) in the water tank 52 of the open-circulation cooling tower simulation device (Example 2), and the other unit was inserted into a T-shaped tubular member 56 installed in the middle of the circulation piping 60 (Comparative Example 2). In addition, a water spray pipe 64 was installed above the water tank 52 to perform showering within the open-circulation cooling tower simulation device. Each measurement unit 46 was electrically connected to a data logger 58 for communication. The measurement unit 46 immersed in the water tank 52 was positioned so that the angle between the excitation light emission unit / fluorescence receiving unit 40 and the still water surface in the lower water tank was 30°. The water tank 52 was covered with a blackout curtain to shield the entire unit from light.

[0079] The fluorescence of the circulating cooling water was measured using each of the two measuring units 46. Additionally, the fluorescence of the circulating cooling water was measured using a stationary fluorometer. The measurement error was calculated using Equation 1. A value closer to 0% indicates a more accurate measurement.

[0080] Figure 10 shows the water temperature (°C) and measurement error (%) as a percentage of the operating time (hr). Submerging a portion of the fluorometer's measuring unit 46 in the water tank 52 resulted in a smaller measurement error compared to inserting it into the circulation pipe 60. This is thought to be because showering within the open-circulation cooling tower simulation device increased the temperature of the gas phase inside the device, eliminating the temperature difference between the ambient temperature and the water temperature.

[0081] [Experiment 3 (Verification of the effectiveness of light-shielding material)] A test was conducted to verify the effectiveness of the light-shielding material under the following conditions.

[0082] <Comparative Example 3: Without light-shielding material> Raw water: Sagamihara City water Equipment: Simulated open-circulation cooling tower (Figure 11) Fluorescence photometer: Turner Design Little Dipper 2 Fluorescent substance: 1,3,6,8-Sodium pyrenetetrasulfonate Fluorescent substance concentration: Adjusted so that the concentration in the circulating cooling water is 120 μg / L.

[0083] As shown in Figure 11, the measuring unit 46 of the fluorophotometer was completely immersed in the water tank 52 of the open-circulation cooling tower simulation device. Two artificial sunlight sources 62 were installed above the water tank 52 to artificially generate sunlight and irradiate the water tank 52 from above. In addition, a water spray pipe 64 was installed above the water tank 52 and below the artificial sunlight sources 62 to perform showering within the open-circulation cooling tower simulation device, generating bubbles in the water tank 52. In Comparative Example 3, the measuring unit 46 was immersed in the water tank 52 of the open-circulation cooling tower simulation device without attaching a light-shielding member, and the angle between the excitation light emission unit / fluorescence receiving unit 40 and the still water surface of the lower water tank was rotated in the range of 0° to 180°, with the angle when the central axis of the measuring unit 46 is horizontal being defined as 90°. Figure 13 shows the measured value of PTSA (μg / L) for each rotation angle (°) of the fluorophotometer.

[0084] At 0°, bubbles accumulated in the fluorescence light receiving section of the measurement unit 46, making accurate measurement impossible. Between 30° and 90°, although there was almost no bubble accumulation, the light of the same wavelength as the fluorescence of the fluorescent substance contained in the artificial sunlight changed angle due to refraction and scattering by the bubbles and entered the fluorescence light receiving section. In addition, the measurement values ​​were assumed to have been inflated because the light of the same wavelength as the fluorescence of the fluorescent substance with this changed angle, as well as the fluorescence of the fluorescent substance emitted by the excitation light, were received (see Figure 14). Between 135° and 180°, the fluorescence light receiving section received ambient light along with the fluorescence, so it is thought that the fluorescence intensity decreased relatively and the measurement values ​​decreased.

[0085] <Example 3: With light-shielding material> Raw water: Sagamihara City water Equipment: Simulated open-circulation cooling tower (Figure 12) Fluorescence photometer: Turner Design Little Dipper 2 Fluorescent substance: 1,3,6,8-Sodium pyrenetetrasulfonate Fluorescent substance concentration: Adjusted so that the concentration in the circulating cooling water is 120 μg / L. Light-shielding material: Commercially available PVC pipe tee fitting

[0086] In Example 3, the procedure was the same as in Comparative Example 2, except that a light-shielding member 50 was attached to cover the fluorescence light-receiving part of the measurement unit 46 and immersed in the water tank 52 of the open circulation cooling tower simulation device. The angle between the excitation light emission unit / fluorescence light-receiving part 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 Figure 13.

[0087] At 0°, bubbles accumulated in the fluorescence light receiving section of the measurement unit 46, making accurate measurement impossible. Between 30° and 180°, attaching the light-shielding member 50 suppresses the entry of light into the fluorescence light receiving section by blocking light of the same wavelength as the fluorescence of the fluorescent substance contained in artificial sunlight, and also suppresses the decrease in relative intensity due to ambient light, so the measured values ​​are considered to be stable (see Figure 15).

[0088] [Experiment 4 (Verification of the effectiveness of cleaning)] The effectiveness of the cleaning was verified under the following conditions.

[0089] <Example 4> Raw water: Sagamihara City water (bouillon added once a day) Equipment: Simulated open-circulation cooling tower (Figure 16) Fluorescence photometer: Pixis ST-500 Fluorescent substance: 1,3,6,8-Sodium pyrenetetrasulfonate Fluorescent substance concentration: Adjusted so that the concentration in the circulating cooling water is 100 μg / L. Bacterial measurement: Sanai Biochecker TTC Cleaning function: Jet cleaning Washing interval: Once a day

[0090] In the same manner as in Example 3 and Comparative Example 3, showering was performed in the open-circulation cooling tower simulation device to generate bubbles in the water tank 52. Also, in the same manner as in Example 3 and Comparative Example 3, artificial sunlight was generated and irradiated. The artificial sunlight was irradiated for 12 hours and then turned off for 12 hours.

[0091] In addition, two identical units of the fluorophotometer's measuring unit 46 were prepared and immersed in the water tank 52 of the open-circulation cooling tower simulation device. One of the immersed measuring unit 46 was equipped with a cleaning function. The other measuring unit 46 was not equipped with a cleaning function. As a cleaning function, air was supplied through the air supply pipe 66 so that it struck the surface of the fluorescence light receiving part of the measuring unit 46. The measurement error was calculated using the above formula 1. Figure 17 shows the bacterial count (CFU / mL) and measurement error (%) as a function of operating time (hr) in Example 4.

[0092] Thus, adding a cleaning function helped to suppress measurement errors.

[0093] As described above, in the embodiment, the concentration of fluorescent substances in the circulating cooling water of the cooling tower was measured accurately and with minimal influence from temperature, ambient light, and bubbles. [Explanation of Symbols]

[0094] 1 Cooling tower, 3 Measuring device, 10 Lower water tank, 12 Fan, 14 Sprinkler tank, 16 Packing material, 18 Gangway plate, 20 Fluorescent photometer, 22, 54 Circulation pump, 24 Heat exchanger, 26 Chemical tank, 28 Chemical pump, 30, 60 Circulation piping, 32 Chemical piping, 34 Receiving unit, 36 Calculation unit, 38 Control unit, 40 Excitation light emission unit / Fluorescence receiving unit, 40a Excitation light emission unit, 40b Fluorescence receiving unit, 42 Excitation light source, 44 Photodetector, 46 Measuring 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 piping.

Claims

1. A water treatment chemical measuring device for measuring the concentration of water treatment chemicals in the circulating cooling water of a cooling tower, An additive means for adding a water treatment chemical and a fluorescent substance as a tracer substance to the circulating cooling water, A fluorophotometer having a measuring unit including a fluorescence light receiving unit, which optically measures the fluorescence of the fluorescent substance present in the circulating cooling water, Equipped with, At least the fluorescence light receiving part of the measuring unit is immersed in a location in the lower water tank that stores the circulating cooling water in the cooling tower where the flow velocity of the circulating cooling water in the operating cooling tower is 0.001 m / s or more. A water treatment chemical measuring device characterized in that it is shielded from light so as to suppress the entry of ambient light entering from outside the cooling tower into the fluorescence light receiving part of the fluorescence photometer.

2. A measuring device for water treatment chemicals according to claim 1, The fluorescent photometer is a device for measuring water treatment chemicals, characterized in that it has a cleaning function for cleaning the fluorescent light receiving section.

3. A measuring device for water treatment chemicals according to claim 1 or 2, A water treatment chemical measuring device characterized by controlling the concentration of the water treatment chemical in the circulating cooling water based on the measurement value of the fluorescence photometer.

4. A method for measuring the concentration of water treatment chemicals in the circulating cooling water of a cooling tower, 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 in which the fluorescence of the fluorescent substance present in the circulating cooling water is optically measured using a fluorescence photometer having a measuring unit that includes a fluorescence light receiving unit, Includes, At least the fluorescence light receiving part of the measuring unit is immersed in a location in the lower water tank that stores the circulating cooling water in the cooling tower where the flow velocity of the circulating cooling water in the operating cooling tower is 0.001 m / s or more. A method for measuring water treatment chemicals, characterized in that the cooling tower is shielded from external light entering from outside so as to prevent it from entering the fluorescence light receiving part of the fluorescence photometer.

5. A method for measuring water treatment chemicals according to claim 4, A method for measuring water treatment chemicals, characterized in that the fluorescent photometer has a cleaning function for cleaning the fluorescent light receiving section.

6. A method for measuring water treatment chemicals according to claim 4 or 5, A method for measuring water treatment chemicals, characterized by controlling the concentration of the water treatment chemicals in the circulating cooling water based on the measurement value of the fluorescence photometer.

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