JPH10142219A - Water quality control method for circulation cooling water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water quality control method for circulation cooling water by controlling a blow displacement and a drug injection amount in a cooling water circulating system. SOLUTION: A part of circulation cooling water is sampled through a sampling pipe 113 and is lead to a tube 121 of a contamination level gauge 120 and a corrosion level gauge 130 respectively. Heating the outside of the tube 121, the amount of scale accumulated inside of the tube 121 is determined, based on condition of heat conduction. A pair of metal electrodes is Immersed into a water tank of the corrosion level gauge 130 to measure a coupling current between the metal electrodes, electrochemical current noise, electrochemical potential noise, and a corrosion level (mm) of a narrow piece of metal. Based on these measured data, water quality of the circulation cooling water and an accumulated scale amount are determined, then a displacement of the circulation cooling water in a blow discharging device 109, 110 and a drug injection amount in a drug injection for water treatment device 103 are controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for managing the quality of circulating cooling water, and more particularly to a method for managing the quality of circulating cooling water in a cooling tower.

[0002]

2. Description of the Related Art In a chemical plant, cooling water has conventionally been used for equipment such as a reactor, a distillation tower, and a heat exchanger. In particular, circulating cooling performed by a cooling tower (cold water tower) is used. Water is heavily used. The cooling tower is a device that evaporates water by bringing circulating cooling water into direct contact with air and cools the water by its latent heat.To adopt a configuration in which cooling water and air come into direct contact, simply use air temperature. The heat transfer efficiency is higher than that of an air-cooled heat exchanger that removes heat by increasing the heat transfer rate.

[0003] In the open type circulating cooling water system, various water treatment chemicals are added to the cooling water to prevent corrosion in the cooling tower,
The scale and slime are prevented from adhering. In order to make the addition of these water treatment chemicals effective, it is necessary to maintain the concentration of the water treatment chemical in the cooling water in a desired range. In the open type circulating cooling water system, since a part of the circulating cooling water evaporates in the cooling tower, salts such as calcium and magnesium contained in the makeup water and brought into the system or SiO
It is known that _{2 and the} like are concentrated in the circulating cooling water system and cause scale formation, thereby lowering the heat exchange efficiency.
For this reason, a part of the concentrated cooling water is blown and discharged out of the system. Makeup water corresponding to the blown water and an anticorrosive (corrosion inhibitor)
Replenishment with water treatment chemicals such as water and scale inhibitors has been performed.

[0004] The injection of chemicals such as the above anticorrosive and scale inhibitor is determined in accordance with the amount of water discharged by blow discharge and the amount of replenished water corresponding to the amount of water lost due to evaporation, scattering, leakage and the like. However, it is difficult to actually measure the amount of water loss, and since the amount of water loss is estimated experimentally or empirically, it is not always necessary to estimate an accurate amount of makeup water and to maintain the drug at a desired concentration. It's not easy. In order to solve this problem, the electric conductivity (conductivity) of the circulating cooling water is measured as a method of controlling the injection of chemicals such as anticorrosives and scale inhibitors, and blow-out is performed automatically so that the value becomes constant. Methods for adjusting the amount have been proposed.

In the above-mentioned proposed method, when the electric conductivity of the circulating cooling water is higher than a predetermined value, the cooling water is blown out and replenished with an amount of make-up water corresponding to the blow-off, and the replenishing water amount is further reduced. Inject the appropriate amount of water treatment chemical.
Conversely, when the electric conductivity is lower than the predetermined value, the blow-out and the injection of the chemical are stopped.

[0006]

The above-mentioned proposed method has a main object of adjusting the concentration of a drug, and indirectly estimates the ion concentration of a corrosive component. Therefore, if the water quality of the circulating cooling water changes, but a change that does not significantly affect the electrical conductivity itself of the circulating cooling water occurs, a change in the concentration of a corrosion factor such as chloride ions cannot be detected. For example, when the chloride ions increase and the sulfate ions decrease, and the electric conductivity of the entire circulating cooling water balances, such an increase in the corrosive factor cannot be detected.

When some of the salts existing in the form of ions precipitate in the circulating cooling water, for example, calcium salts,
In particular, when calcium carbonate precipitates, the electric conductivity of the circulating cooling water decreases, so that the blow discharge flow rate is adjusted to decrease. However, in this case, scale is generated by precipitation of calcium carbonate, and in the above-described proposed method, control in a direction opposite to prevention of scale adhesion is performed.

[0008] As described above, the method of controlling the water quality by the electric conductivity is based on the corrosive factors in the circulating cooling water,
It was unsuitable for control to prevent an increase in the amount of adhered scale. For this reason, conventionally, there has been a demand for a method capable of appropriately controlling the quality of the circulating cooling water.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and is intended to control the quality of circulating cooling water in a cooling tower, in particular, to control corrosion prevention based on grasp of corrosive factors and to grasp a dirt coefficient such as scale. It is an object of the present invention to provide a method for managing the quality of circulating cooling water, which can appropriately perform scale prevention management based on the water quality.

[0010]

According to a first aspect of the present invention, there is provided a method of controlling the quality of circulating cooling water, comprising the steps of: providing a cooling water circulation system having a blow discharge device and a water treatment chemical injection device; In the method for controlling the quality of circulating cooling water, a part of the circulating cooling water is sampled, and a coupling current and a electrochemical current noise between a pair of metal electrodes immersed in the sampled cooling water are measured. Determining the quality of the circulating cooling water based on the obtained data, and controlling the discharge amount of the circulating cooling water by the blow discharge device and / or the chemical injection amount by the water treatment chemical injection device based on the determination result. I do.

In a preferred embodiment of the present invention, a pair of metal electrodes, at least one of which is made of another metal electrode, immersed in the sampled cooling water is used to measure electrochemical potential noise therebetween, A configuration is adopted in which the quality of the cooling water is determined based on the measured coupling current, electrochemical current noise, and electrochemical potential noise.

In addition to the above configuration, it is a preferable embodiment of the present invention to measure the degree of corrosion of the metal immersed in the sampled cooling water. The water quality management method according to the first aspect of the present invention is preferably used particularly for controlling the injection amount of an anticorrosive.

[0013] A water quality management method according to a second aspect of the present invention is the water quality management method for circulating cooling water in a cooling water circulation system provided with a blow discharge device and a water treatment chemical injection device. And heats from outside the tube containing the circulating cooling water, measures the state of heat transfer from the tube, estimates the amount of scale attached to the tube based on the measurement result, and blows out based on the estimation result. It is characterized in that the amount of circulating cooling water discharged by the device and / or the amount of drug injected by the water treatment agent injection device is controlled.

[0014] The water quality management method according to the second aspect, in particular,
It is preferably used for controlling the injection amount of the scale inhibitor.

According to the water quality management method of the present invention, the quality of the circulating cooling water or the amount of scale attached can be quantitatively grasped, so that the quality of the circulating cooling water in the cooling tower can be properly controlled.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the configuration of a circulating cooling water quality control method according to the present invention. FIG. 1 is a block diagram of a circulating cooling water system including a cooling tower for performing the method of the present embodiment. In the figure, 101 is a cooling tower, 102 is a heat exchanger, 103 is a water treatment device, and a cooling water supply pipe 104 and a cooling water return pipe 105 are arranged between the cooling tower 101 and the heat exchanger 102. The cooling water supply pipe 104 is provided with a circulation pump 106.

The cooling tower 101 is provided with a cooler (not shown) in a casing thereof, and a sprinkler (not shown) is provided above the cooler, and a sprinkler (not shown) is provided below the cooler. A not-shown pan for receiving the cooled water is provided. A cooling water return pipe 105 is connected to the sprinkler, and a cooling water supply pipe 104 is connected to the tray. A fan is installed on the upper part of the casing, and a ventilation opening is provided on the side surface.

The heat exchanger 102 functions as a heat storage unit, and the cooling tower 101 functions as a heat radiation unit. Cooling tower 101
The cooling water inside is supplied to the heat exchanger 102 via the cooling supply pipe 104 by the circulation pump 106. The water that has undergone heat exchange in the heat exchanger 102 is returned to the cooling tower 101 via the cooling water return pipe 105 as circulating cooling water. In this manner, the cooling tower 101, the cooling water supply pipe 104, the heat exchanger 102, and the cooling water return pipe 105 constitute a cooling water circulation system. In order to supply makeup water to the circulation system, a makeup water supply pipe 107 is installed so as to be inserted into the casing of the cooling tower 101, and forms a makeup system.

As a blow discharge system for blowing out the cooling water from the circulating system, either a method of providing a blow valve in a branch pipe branched from the cooling water supply pipe 104 or a method of providing a blow pipe in a tray is adopted. it can. In the present embodiment, the latter method is adopted, and a blow pipe 108 is connected to the receiving tray, and a blow pump 109 and a blow valve 110 are provided corresponding to the blow pipe 108.

The water treatment apparatus 103 is installed for injecting a water treatment agent such as an anticorrosive or a scale inhibitor into the circulation system. The medicine is sent to the cooling tower 101 via the medicine pipe 112 by the medicine injection pump 111. The chemical pipe 112 is installed so as to be inserted into the casing of the cooling tower 101.

A sampling pipe 113 for drawing out cooling water is branched from the cooling water supply pipe 104, and the sampling pipe 113 is connected to a tube 121 of the dirt measuring device 120 and a water tank of the corrosion measuring device 130. Have been.

As will be described later, the corrosion measuring device 130
Using the electrochemical noise method, the coupling current between the metal electrodes immersed in the circulating cooling water, the electrochemical current noise and the electrochemical potential noise were measured, and from this measurement data,
It is used to determine the corrosion rate (corrosion rate) and the form of corrosion. The measurement result is input to the control device 140, and the control device 140 outputs a control signal to the blow valve 110 and the chemical injection pump 111. For example, when it is determined that the metal corrosion rate due to the circulating cooling water has increased, the blow valve 110 is opened to blow out and discharge the circulating cooling water, supply makeup water, and operate the chemical pump 111. Control to adjust the dose of anticorrosive.

In the contamination measuring device 120, a tube 121 is used.
The dirt coefficient is calculated by passing circulating cooling water through the inside, heating the tube 121 from the outside by a heater 122, and measuring the heat transfer during this heating.

The result of measurement by the dirt measuring device 120 is similarly input to the control device 140, which outputs control signals for the blow valve 110 and the chemical injection pump 111. For example, when it is determined that the water quality has a large dirt coefficient and the scale is likely to precipitate, the blow valve 110 is opened to blow out and discharge the circulating cooling water, supply the makeup water, and operate the chemical injection pump 111. Control to adjust the dose of scale inhibitor.

FIG. 2 shows the corrosion measuring device 130 shown in FIG.
The details are shown below. The corrosion measuring apparatus 130 includes a water tank 11 that stores the sampled cooling water 12, and the circulating cooling water is introduced into the water tank 11 at a predetermined flow rate from the tube 121 in FIG. The water is returned from the water tank 11 to the cooling water circulation system via a pipe (not shown). In the cooling water 12 in the water tank 11, three measurement electrodes having substantially the same material as the metal surface to be measured for corrosion, that is, the first measurement electrode,
The second and third electrodes 21, 22, 23 are immersed. Each of the electrodes 21 to 23 is placed under the same temperature condition that is substantially the same corrosion condition as the metal surface to be measured.

A current measuring circuit having almost zero internal resistance, that is, a so-called zero resistance ammeter, is provided between a first electrode pair consisting of a first electrode 21 and a second electrode 22.
rter) 24 is connected. In addition, a signal voltage can be measured between the second electrode pair including the second electrode 22 and the third electrode 23 without exerting any electric influence on the electrode side.
A buffer circuit 25 which is an amplifier circuit having an extremely large input impedance is connected.

With the above configuration, the first electrode 21 and the second
A coupling current (coupling current) flows between the first pair of electrodes 22 in accordance with the degree of progress of corrosion on the surfaces of both electrodes. This coupling current is measured by the non-resistance ammeter 24, processed by the signal processing circuit 31 and sent to the computer 71 as a DC current component (I _mean ) a, and by the filter circuit of the signal processing circuit 32, After the components in the frequency domain of about 1 Hz or less, which is the frequency domain, are extracted, predetermined signal processing is performed.

In the present embodiment, in particular, the coupling current is filtered by a band-pass filter circuit in the signal processing circuit 32 so that 0.01% of the coupling current is output.
Frequency band signal component of about ~1Hz is extracted by performing a predetermined signal processing to this, the electrochemical current noise (I _n) b is obtained. The obtained electrochemical current noise b is also accumulated in the data storage unit 72 of the computer 71 in time series. Alternatively, the electrochemical current noise b can also be obtained by performing a predetermined calculation process on the DC component a (I _mean ) of the coupling current taken into the computer 71 to obtain the standard deviation. Is obtained.

The potential difference between the second electrode pair consisting of the second electrode 22 and the third electrode 23 is measured by a buffer circuit 25, and from this potential difference, a filter circuit in the signal processing circuit 33 uses the potential difference of about 1 Hz or less. Are extracted. In the present embodiment, the potential difference fluctuation in a frequency band of about 0.01 to 1 Hz is extracted by using a band-pass filter circuit, and the potential difference fluctuation is signal-processed to obtain the electrochemical potential noise c (V _n ). Get. The electrochemical potential noise c is stored in the data storage unit 7 of the computer 71.
2 are stored in chronological order. Instead of this, the electrochemical potential noise c is obtained by directly calculating the potential difference from the computer 71.
Is obtained in the same way by performing a predetermined calculation process and calculating the standard deviation.

FIGS. 3A and 3B show the direct current component (I _mean ) a of the coupling current in the above embodiment.
Arithmetic circuit 3 for calculating electrochemical current noise b (I _n )
1, 32, and the configuration of the arithmetic circuit 33 for obtaining the electrochemical potential noise c (V _n ), respectively. These arithmetic circuits 31 to 33 are an example of processing each data in an analog manner.

In FIG. 3A, a current (current signal) between a first electrode pair composed of a first electrode 21 and a second electrode 22 is measured by a non-resistance ammeter 24 as a coupling current. You. The coupling current is input to the signal processing circuit 31, and is first input to a log converter 41 having a built-in RMS processing circuit, DC converter, and log converter, not shown. In the logarithmic converter 41, the RMS processing circuit portion obtains the mean square of the coupling current, then the DC converter portion converts the mean square to direct current, and then converts the mean square to logarithmic in the logarithmic conversion circuit portion. You. The output of the logarithmic converter 41 is sent to an A / D converter 42, where it is converted into a digital signal, and the DC component a (I
_mean ) is input to the computer 71.

The coupling current measured by the non-resistance ammeter 24 is further input to the band-pass filter circuit 51 of the signal processing circuit 32, where the coupling current is 0.01 to 1H.
After extracting a component in a frequency band of about z, the logarithmic converter 5 having the same configuration as the logarithmic converter 41 described above.
2, the signal is subjected to predetermined signal processing and logarithmic conversion, and further converted to a digital signal by the A / D converter 53, after which the electrochemical current noise (I _n ) b
Is input to the computer 71.

The potential difference (voltage signal) between the second electrode pair consisting of the second electrode 22 and the third electrode 23 is shown in FIG.
As shown in (b), after a component in the frequency band of about 0.01 to 1 Hz is measured by the buffer circuit 25 and extracted by the band-pass filter circuit 61 in the signal processing circuit 33, the logarithmic converter is used. The data is input to a logarithmic converter 62 having a configuration similar to that of 41 and 52. Predetermined signal processing and logarithmic conversion is performed by a logarithmic converter 62, furthermore, by the A / D converter 63 after being converted into a digital signal, is input as an electrochemical potential noise (V _n) c to the computer 71.

Instead of the signal processing circuits shown in FIGS. 3A and 3B, a circuit configuration for performing digital processing can be adopted, and similar signals can be obtained by such a digital circuit configuration.

In FIG. 2, a metal strip 20 is further immersed in cooling water 12 in a water tank 11. The metal strip 20 is made of a metal piece of the same material as the metal surface in the circulating water cooling system for which corrosion is to be measured, and is taken out after being immersed in the cooling water 12 in the water tank 11 for a certain time. The thickness reduction (mm) of the metal strip 20 due to corrosion is measured, and the measured data is input by the input device 26 and stored in the storage device 72 of the computer 71 as the corrosion degree d.

In the computer 71, a data storage unit 72
, Ie, the coupling current a (I _mean ), the electrochemical current noise b (I _n ),
Based on the measured data consisting of the electrochemical potential noise c (V _n ) and the corrosion rate d, the following equations (1), (2),
Using (3), each of the corrosion factors K ₁ , K ₂ , and K ₃ is calculated by the corresponding calculation means 73, 74, and 75.

Calculation of the first corrosion coefficient K ₁ : C _n = K ₁ ΣI
Using the _mean calculating a _{K 1 = C n / ΣI mean} ------------ K 1 (1). Here, C _n indicates the degree of corrosion (mm) d after immersing the metal strip 20 in the corrosive liquid 12 for a predetermined time, and ΔI _mean is the current I _mean within a predetermined time corresponding to the degree of corrosion C _n. Shows the accumulated amount (coulomb) of.

Calculation of the second corrosion coefficient K ₂ : C _n = K ₂ / Σ
Calculating the K ₂ from utilizing _{R n = K 2 · ΣI n} / V n K 2 = C n / Σ (I n / V n) ------------ (2) . Here, R _n is electrochemical resistance noise (Ω · sec), and Σ (I _n / V _n ) is I _n (electrochemical current noise b) within a predetermined time corresponding to the corrosion degree C _n. / V _n (electrochemical potential noise c) is shown (coulomb / volt).

Calculation of the third corrosion coefficient K ₃ : C _n = √ (K _{3
· ΣI n · ΣI mean / ΣV} n) by using the calculated the ^{_{K 3 = C n 2 / (}} ΣI n · ΣI mean / ΣV n) -------- (3) from the K _3. Where ΣI _n , ΣI _mean , and
ΣV _n is the accumulated amount (coulomb) of I _n (electrochemical current noise b), the accumulated amount (coulomb) of I _mean (coupling current a) within a predetermined time corresponding to the corrosion degree C _n , and accumulation amount of V _n (electrochemical potential noise c) a (volt · sec) shown.

Next, the calculated corrosion coefficients K ₁ , K ₂ , K ₃
Used, the particular I was measured per time period _mean (coupling current a), I _n (electrochemical current noise b), and, based on the measurement data V _n (electrochemical potential noise c) Te, formula (4), (5), using (6), by the corresponding calculation means 76, 77 and 78, each corrosion rate _{C 1, C 2, C 3} (mm / year) is calculated .

Calculation of the first corrosion rate C ₁ : C ₁ = K ₁ · I _mean −−−−−−−−−−− (4)

Calculation of the second corrosion rate C ₂ : C ₂ = K ₂ · I _n / V _n −−−−−−−−−− (5)

Calculation of the third corrosion rate C ₃ : C ₃ = √ (K ₃ · I _n · I _mean / V _n ------ (6)

Subsequently, the respective corrosion rates C ₁ , C ₂ , C ₃ (mm / year) calculated above are arithmetically averaged by the calculating means 79, and this value C ₄ is used as the average corrosion rate.

Calculation of the average corrosion rate C ₄ : C ₄ = (C ₁ + C ₂ + C ₃ ) / 3 (3)

The transitions of the corrosion rates C ₁ , C ₂ , C ₃ and the average corrosion rate C ₄ obtained as described above are represented by CR
It is output on the screen of T13 or output and displayed as a printout by the printer 14. Similarly, it is possible to output and display the instantaneous value of the corrosion rate and the transition of a trend expressing the instantaneous value in a time series.

Instead of the above, the corrosion rates C ₁ , C ₂ , C ₃ ,
In addition to the output of C ₄ , I _mean (coupling current a)
, I _n (electrochemical current noise b) and V _n (electrochemical potential noise c) instantaneous values of measured data, trends of time-series trends, and accumulated values thereof Can also be displayed individually or in association with each other.

FIG. 4 is a block diagram showing a corrosion degree measuring apparatus for performing the method according to the second embodiment of the present invention. The corrosion degree measuring apparatus 130A according to the present embodiment performs the determination itself as to the presence or absence of corrosion inside the computer 71A instead of the determination as to whether or not corrosion is performed outside the computer 71 in FIG. The configuration of the electrodes and the like in the water tank 11 and the configuration of each calculation unit and the like are the same as the configuration of the previous embodiment except for the configuration inside the computer. Inside the computer 71A, a data storage unit 72 for storing data similar to that shown in FIG. 2 and first processing units 81 to 8 constituting a signal processing unit
4 and second processing units 91 to 97 are shown.
The corresponding processing contents are shown in the flow symbol form in the calculation unit and the judgment unit in each signal processing unit.

In this embodiment, the first processing units 81 to 8
In 4, the degree of corrosion is determined by associating the coupling current a (I _mean ) with the electrochemical current noise b (I _n ) based on the data obtained from the data storage unit 72. In this case, I _n (electrochemical current noise b) / I
The ratio of the _mean (coupling current a) calculated in the I _n / I _mean comparator unit 81, divides the form of corrosion in the following 4 forms,
The corresponding determination units 82 to 83 make the determination.

Overall corrosion: 0.001 <I _n / I _mean <0.01 Mixed corrosion: 0.01 <I _n / I _mean <0.1 Local (partial) corrosion: 0.1 <I _n / I _mean <1.0 Pitching (pitting corrosion): 1.0 <I _n / I _mean

The judgment of the overall corrosion is made by the judgment part 82, the judgment of the mixed corrosion and the local corrosion is made by the judgment part 83, and the judgment of the pitching is made by the judgment part 84, and a corresponding alarm is output. Thus, in the first processing unit 81 to 84, I _n
The ratio of / I _mean is determined, and occurrence of corrosion is determined from the instantaneous value. Alternatively, instead of this, I _n / I _mean comparing unit 81
By judging the transition of the trend in which the instantaneous value of the ratio obtained in the above is represented in a time series, the transition of the form of corrosion can also be grasped. In local corrosion, it is not enough to determine quantitatively such as corrosion rate or degree of corrosion in general corrosion, and it is important to determine the form of the corrosion.

[0052] In the second processing unit 91 to 97, as described below, I _n (electrochemical current noise b), and / or analyzes the signal waveform of V _n (electrochemical potential noise c) , The form of corrosion is determined. In particular, as for the local corrosion, since the low frequency noise component increases in the measurement data of each noise signal, the peak waveform signal of the low frequency noise component is analyzed to determine the form of the local corrosion.

The above form determination is performed in the following manner. (A) Judgment is made by comparing the ratio of the peak height / peak width of the noise signal. (B) Judgment is made by comparing the magnitude of the peak repetition period of the noise signal. (C) The judgment is made by comparing the number of low frequency peak components of the noise signal.

First, the I _n extracted from the data storage unit 72
The peak waveform of the signal of (electrochemical current noise b) or V _n (electrochemical potential noise c) is analyzed by the noise peak waveform analyzer 91. Subsequently, the ratio of the peak height / peak width of the analyzed signal is obtained by the height / width comparison unit 92. Further, the repetition period of the noise peak is detected by the repetition period detection unit 93, and 0.01 to
The number of low frequency component peaks in the range of 1 Hz (the number of low frequency component peaks) is detected. Each comparing section 92 and detecting section 93,
By discriminating the result obtained by 94 in the following three ways, the corresponding determination units 95 to 97 determine the corrosion mode, and output that fact.

(A) The ratio of peak height / peak width is small,
In addition, when at least one of the peak repetition period and the number of low frequency component peaks is small, the overall corrosion determination unit 95 determines that there is general corrosion.

(B) The ratio of peak height / peak width is large,
When at least one of the peak repetition period and the number of low frequency component peaks is large, the stress corrosion cracking determination unit 9
According to No. 6, it is determined to be stress corrosion cracking. .

(C) In the intermediate region between the above (a) and (b), the pitching judging section 97 judges pitching.

The result of the above determination is based on the CRT 13 or the printer 1
4 is displayed. Instead of the above, the instantaneous value of the ratio and the trend expressed in a time series are displayed on the CRT 13 or printed out by the printer 14, and the transition is observed to grasp the corrosion form. You may.

Regarding the numerical values used for the above judgment criteria, in advance, data on a sample test piece made of a standard metal that has undergone general corrosion, stress corrosion cracking or pitting in circulating cooling water having a known water quality is obtained. It is preferable to determine a criterion value for the check item.

The water quality of the circulating cooling water is determined based on the determination of the presence or absence and the degree of corrosion of the electrode obtained as described above, and based on this, the blow discharge amount to the circulating water cooling system and the anticorrosive agent are determined. The injection amount can be adjusted.

As described above, in the water quality management method of the present embodiment, in the water quality management of the circulating cooling water in the cooling tower, the corrosion prevention management of the metal material of the circulating cooling water system based on the grasp of the corrosive factors, the scale adhesion, etc. And the prevention of scale of the heat exchange material based on the grasp of the fouling coefficient.

Although the present invention has been described based on the preferred embodiment, the method for managing the water quality of the circulating cooling water of the present invention is not limited to the configuration of the above-described embodiment. Various modifications and changes from the configuration of the embodiment are also included in the scope of the present invention.

[0063]

As described above, according to the present invention,
The quality of the circulating cooling water in the cooling tower can be quantitatively grasped,
There is an advantage that the blow discharge amount and the medicine injection amount can be quantitatively controlled.

[Brief description of the drawings]

FIG. 1 is a system diagram of a cooling water circulation system that implements a method for managing the quality of circulating cooling water according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a corrosion degree measuring device in the cooling water circulation system of FIG.

FIGS. 3A and 3B are block diagrams each showing a configuration of a signal processing circuit of the corrosion rate measuring device of FIG. 2;

FIG. 4 is a schematic block diagram showing the configuration and processing of a signal processing circuit of a corrosion rate measuring device that implements a method for managing the quality of circulating cooling water according to a second embodiment of the present invention.

[Explanation of symbols]

101 Cooling Tower 102 Heat Exchanger 103 Water Treatment Device 104 Cooling Water Supply Pipe 105 Cooling Water Return Pipe 106 Circulation Pump 107 Makeup Water Supply Pipe 108 Blow Pipe 109 Blow Pump 110 Blow Valve 111 Chemical Injection Pump 112 Chemical Pipe 113 Sampling Pipe 120 Dirt Measuring device 121 Tube 122 Heater 130, 130A Corrosion measuring device 140 Control device 11 Water tank 12 Cooling water 13 CRT 14 Printer 20 Metal strip 21, 22, 23 Electrode 24 Resistance current meter 25 Buffer circuit 26 Input device 31, 32, 33 Signal Processing Circuit 41 Logarithmic Converter 42 A / D Converter 51 Bandpass Filter 52 Logarithmic Converter 53 A / D Converter 61 Bandpass Filter 62 Logarithmic Converter 63 A / D Converter 71 Computer 72 data storage unit 73-79 calculating means 81 I _n / I _mean comparator unit 82 to 84 judging unit 91 noise peak analysis unit 92 peak height / width comparator unit 93 repetition period detector 94 low frequency components peak number detecting portion 95 97 Judgment unit

Claims (6)

[Claims] 1. A method for controlling the quality of circulating cooling water in a cooling water circulation system provided with a blow discharge device and a water treatment chemical injection device, wherein a part of the circulating cooling water is sampled and immersed in the sampled cooling water. The coupling current between the metal electrodes and the electrochemical current noise are measured, the quality of the circulating cooling water is determined based on the measured data, and the circulating cooling water is blown by the blow discharge device based on the determination result. A water quality management method for circulating cooling water, comprising controlling a discharge amount and / or a drug injection amount by a water treatment drug injection device. 2. Electrochemical potential noise between a pair of metal electrodes, at least one of which is made of another metal electrode, immersed in the sampled cooling water is further measured, and the measured coupling current, electrochemical The water quality management method for circulating cooling water according to claim 1, wherein the quality of the cooling water is determined based on static current noise and electrochemical potential noise. 3. The method for controlling the quality of circulating cooling water according to claim 1, further comprising measuring a corrosion degree of the metal material immersed in the sampled cooling water. 4. The method according to claim 1, wherein the chemical is an anticorrosive. 5. A method for managing the quality of circulating cooling water in a cooling water circulating system having a blow discharge device and a water treatment chemical injection device, wherein a part of the circulating cooling water is introduced into a tube and heated from outside the tube; The state of heat transfer from the tube is measured, the amount of scale attached to the tube is estimated based on the measurement result, and the discharge amount of the circulating cooling water and / or the water treatment agent injected by the blow discharge device is estimated based on the estimation result. A water quality management method for circulating cooling water, characterized by controlling a drug injection amount by a device. 6. The method according to claim 5, wherein the chemical is a scale inhibitor.