JP2009243805A - Injecting method of water treatment chemical - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injecting method of a water treatment chemical in an open circulation cooling water system, which economically and easily adjusts the concentration of the water treatment chemical in cooling water to a predetermined concentration, including response to a temperature condition. <P>SOLUTION: In the open circulation cooling water system, cooling water is circulated and supplied to a heat exchanger and is cooled by a cooling tower. Blowing of part of the cooling water is performed, and make-up water is supplied to maintain the concentration rate of the cooling water at a constant level. The water treatment chemical including at least one component of a corrosion prevention component, a scale prevention component and a slime control component, is injected proportionally with respect to the amount of the make-up water. In the injecting method of the water treatment chemical, when outside air temperature T0, a cooling water temperature, or a temperature difference ΔT (= T2-T1) between temperature T1 of cooling water (circulating water) leading from the cooling tower toward the heat exchanger, and temperature T2 of cooling water (circulating water) returning from the heat exchanger to the cooling tower, exceeds a set temperature, a necessary water treatment chemical is additionally injected. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for injecting a water treatment chemical to be injected into an open circulating cooling water system for air conditioning, various industrial use, and the like.

  In the open circulating cooling water system, part of the water is evaporated, so the dissolved matter in the circulating water system is gradually concentrated. As the concentration progresses, calcium and other scales are generated, and further slime damage due to the growth of microorganisms occurs. In addition, there is a problem that corrosion also occurs in the mild steel and copper of the component equipment.

  In order to prevent such problems and ensure safe and efficient operation of the equipment, various water treatment chemicals are injected into the cooling water. Water treatment chemicals injected into the open circulation cooling water system include anti-corrosion ingredients, scale prevention ingredients, slime control ingredients that suppress slime growth, and one-component water treatment with these effects to provide multiple effects. There are drugs.

  The water treatment chemical is effective by maintaining a constant concentration in the cooling water. When the concentration is low, the effect is insufficient and the above-mentioned various problems occur. On the other hand, if the concentration of the water treatment chemical is too high, the cost of the water treatment chemical becomes high and it is uneconomical, and it may cause adverse effects.

  For this reason, various methods for maintaining the concentration of the water treatment chemical in the cooling water above a certain level have been studied for the injection of the water treatment chemical in the open circulation cooling water system.

For example, Patent Documents 1 and 2 include a method of periodically injecting a water treatment chemical by controlling the drug injection pump on and off with a timer.
Japanese Patent Laid-Open No. 08-173971 Japanese Patent Application No. 09-10592

  In the water treatment chemical injection method for controlling the chemical injection pump by the timer disclosed in Patent Documents 1 and 2, in order to inject a constant amount of water treatment chemical every fixed time, the load of the cooling tower and the refrigerator and various It is difficult to change the injection amount of the water treatment chemical according to the temperature condition, and it is difficult to keep the chemical concentration in the cooling water constant. Therefore, in order to ensure a drug concentration higher than a certain level that is really necessary in the cooling water, it is necessary to inject excessively, which is not economical.

In Patent Document 3 and Patent Document 4, a water treatment chemical is used as a tracer substance, or a tracer substance having a concentration proportional to the water treatment chemical is added, and the tracer substance is continuously measured to inject the water treatment chemical. A method of controlling is disclosed.
Japanese Laid-Open Patent Publication No. 4-296665 Japanese Patent Laid-Open No. 2004-322058

  However, in the water treatment chemical injection methods described in Patent Literature 3 and Patent Literature 4, it is possible to maintain the water treatment chemical concentration in the cooling water constant. Adjustments such as additional injections of drugs have not been reached. In addition, since an advanced measurement device is required, the initial investment is large, and the maintenance cost for maintaining and operating the measurement control device safely and with high accuracy becomes high.

Further, Patent Document 5 discloses a method of measuring a replenishment amount of replenishing water with a pulse transmission type flow meter or the like and proportionally injecting a certain amount of water treatment chemical to the replenishing water.
Japanese Patent Application Laid-Open No. 07-119916

  In this method, the chemical concentration in the cooling water can be kept constant by combining with the concentration management of cooling water by automatic blow, which is relatively simple and highly reliable. However, even this method has not yet reached an adjustment such as additionally injecting a water treatment chemical corresponding to a certain temperature condition. Moreover, it is necessary to install an expensive pulse transmission type flow meter in the piping of the makeup water line, which is not an economical and simple method.

  On the other hand, water treatment chemicals such as a scale prevention component and a slime control component may not be able to exert their effects sufficiently under certain temperature conditions unless the concentration of the chemical is increased compared to the normal case.

  For example, when the load of the heat exchanger increases, the temperature of the heat exchanger heat transfer surface rises, and scale failure tends to occur.

  Further, when the water temperature or the outside air temperature becomes high, slime damage is likely to occur. Such a phenomenon is particularly likely to occur in summer. For this reason, the effect of the water treatment chemical can be achieved by injecting a large amount of the water treatment chemical in advance and maintaining the concentration of the water treatment chemical in the cooling water at a high level in normal season or when the outside air temperature rises. It is necessary to exhibit these problems and prevent these obstacles.

  On the other hand, when the load of the heat exchanger is low, the replenishment amount of the replenishing water is small, and the replacement frequency of the cooling water in the open circulation cooling water system is lowered. In this case, the injection frequency of the water treatment chemical injected into the cooling water in proportion to the injection amount of the makeup water also decreases, and the water treatment chemical stays in the open circulating cooling water system for a long time.

  If the water treatment chemical remains in the open circulating cooling water system for a long time, the water treatment chemical itself decomposes with the passage of time, and the concentration of the substantial water treatment chemical in the cooling water decreases. Therefore, when the load of the heat exchanger is low, the amount necessary for sufficiently exerting the effect may be insufficient even when an amount of water treatment chemical proportional to the makeup water is injected. For example, a slime control component having a high decomposition rate is applicable.

  Such a phenomenon is particularly likely to occur in winter. For this reason, in winter, in anticipation of normal or when the outside air temperature drops, water treatment chemicals are injected more than the theoretically required injection amount, and the concentration of water treatment chemicals in the cooling water is kept high. As a result, it is necessary to exert the effect of the water treatment chemical and prevent the failure.

  When water treatment chemicals are injected, they must be injected most effectively and economically according to the heat exchanger load and various temperature conditions. That is, in an open circulation cooling water system, it is important to maintain a concentration of chemicals above a certain level that corresponds to the operating conditions in order to sufficiently exert the effect of the water treatment chemicals.

  Accordingly, the present invention provides an economical and simple method for injecting water treatment chemicals in an open circulating cooling water system that can adjust the concentration of the water treatment chemicals in the cooling water to a predetermined concentration including correspondence to temperature conditions. It is an object to provide a method.

  The present invention is for solving the above-mentioned problems. That is, the present invention according to claims 1 and 2 circulates and supplies cooling water to the heat exchanger, cools the cooling water in the cooling tower, blows a part of the cooling water and supplies makeup water. The cooling water concentration ratio is kept constant, and a water treatment chemical containing at least one of the anticorrosive component, scale preventive component, and slime control component is injected in proportion to the amount of makeup water. Providing a water treatment chemical injection method characterized by additionally injecting a water treatment chemical containing a slime control component when the outside air temperature T0 or the temperature of the cooling water (circulating water) is equal to or higher than a set temperature in the water system, In the above, the temperature difference ΔT (= T2−T1) between the temperature T1 of the cooling water (circulation water) from the cooling tower to the heat exchanger and the temperature T2 of the cooling water (circulation water) returning from the heat exchanger to the cooling tower is , Setting When the temperature below there is provided a method of injecting water treatment agent, which comprises adding injecting water treatment chemicals including slime control components.

  According to the third aspect of the present invention, cooling water is circulated and supplied to the heat exchanger, the cooling water is cooled by a cooling tower, and a part of the cooling water is blown and makeup water is supplied for cooling. In an open circulating cooling water system in which the water concentration ratio is kept constant, and a water treatment chemical containing at least one of anticorrosive ingredients, scale preventive ingredients, and slime control ingredients is injected in proportion to the amount of makeup water. The temperature difference ΔT (= T2−T1) between the temperature T1 of the cooling water (circulation water) from the cooling tower to the heat exchanger and the temperature T2 of the cooling water (circulation water) returning from the heat exchanger to the cooling tower is set. The present invention provides a method for injecting a water treatment agent, which is characterized by additionally injecting a water treatment agent containing a scale inhibiting component when the temperature is higher than the temperature.

  Furthermore, the invention according to claim 4 is characterized in that the injection amount of the water treatment chemical to be additionally injected is determined by a function of a temperature factor at the time of the additional injection. A method is provided.

In addition, the invention according to claim 5 is the temperature T1 (° C.) of the cooling water (circulated water) from the cooling tower to the heat exchanger. From the temperature T2 (° C.) of the cooling water (circulation water) returning to the cooling tower from the heat exchanger, the theoretical makeup water amount (M) to the cooling water is obtained according to the following equation (1), and the theoretical makeup water amount (M) is obtained. The method for injecting a water treatment chemical according to any one of the above, wherein the method is determined as a proportional amount.
M = ((T2−T1) × c × R / Q) × (N / (N−1)) (Expression 1)
M: Theoretical makeup water volume (m3 / h)
c: Specific heat of water (kcal / kg · ° C)
R: Circulating water volume of cooling water (m3 / h)
Q: latent heat of vaporization of water (kcal / kg)
N: Concentration ratio of cooling water (times)

  The invention according to claim 6 is an amount that is proportional to the corrected theoretical makeup water amount (corrected theoretical makeup water amount) by correcting the theoretical makeup water amount using a correction coefficient that is a function of the outside air temperature T0 (° C.). The method for injecting a water treatment agent as described above is characterized by injecting the water treatment agent.

  Since this invention is the above structure, it can maintain and manage the density | concentration of the water treatment chemical | medical agent in cooling water to a truly required density | concentration simply and at low cost.

  Specifically, according to the invention according to claim 1, when the outside air temperature T0 or the temperature of the cooling water is equal to or higher than the set temperature, that is, when the slime control component is further required than the normal management, the slime control component As water treatment chemicals containing water are added, the concentration of water treatment chemicals can be controlled to the level that is truly necessary to prevent slime even if there is a change in temperature factor, and the effects of water treatment chemicals can be maintained. It becomes.

  Both the method of injecting a one-component water treatment agent containing a slime control component and the method of additionally injecting a water treatment agent of only the slime control component can be adopted. The additional injection method is more economical without over-injection of other water treatment agents.

  According to the second aspect of the present invention, when ΔT is equal to or lower than the set temperature, that is, when the load of the heat exchanger is low and the slime control component stays in the cooling water for a long time and is further required than normal management, slime control Since the components are additionally injected, the concentration of the water treatment chemical can be controlled to the concentration necessary for slime prevention even if the temperature factor changes, and the effect of the water treatment chemical can be maintained.

  In addition, either a method of additionally injecting a one-component water treatment agent containing a slime control component or a method of additionally injecting a water treatment agent of only a slime control component can be adopted. It is more economical to inject additional water treatment chemicals separately.

  According to the third aspect of the present invention, when ΔT is equal to or higher than the set temperature, that is, when the load of the heat exchanger is high and the scale prevention component is further required than normal management, the scale prevention component is additionally injected. Even if there is a change in the factor, the concentration of the water treatment chemical can be managed at a concentration necessary for scale prevention, and the effect of the water treatment chemical can be maintained.

  Both the method of additionally injecting a one-component water treatment chemical containing a scale prevention component and the method of additionally injecting a water treatment chemical only of a scale prevention component can be employed. It is more economical to inject additional treatment chemicals separately.

  According to the fourth aspect of the present invention, at the time of additional injection, for example, the injection amount is determined by a function of any one of the temperature factors of the cooling water adopted as the set temperature, T1, T2, or the outside air temperature T0. In other words, when the set temperature is exceeded, the additional injection amount can be changed depending on the degree, for example, the cooling tower in which the operating rate of the heat exchanger is frequently changed, and the outside air temperature such as the turn of the season. Even when the change is large, the water treatment chemical to be added can be managed at a truly necessary concentration, and the effect of the water treatment chemical can be maintained more economically.

  According to the fifth aspect of the present invention, T1 and T2 are measured, and other data is obtained in advance using the value determined for each open circulating cooling water system as input information, and the theoretical makeup water amount is obtained from equation (1). The water treatment chemical 5a in the cooling water 2a can be simply and at low cost even in the water treatment chemical injected in proportion to the makeup water by injecting the water treatment chemical proportional to the theoretical makeup water amount into the cooling water 2a. It can be controlled to an appropriate concentration.

  Accordingly, it is not necessary to install an expensive pulse transmission type flow meter for actually measuring the amount of makeup water 4a as in the prior art, and the amount of makeup water 4a can be grasped simply and at low cost. Further, it is extremely excellent in that it is not necessary to stop the operation of the open circulating cooling water system in order to install the pulse transmission type flow meter, and can be easily applied to the existing open circulating cooling water system.

  Furthermore, according to the invention of claim 6, the theoretical makeup water amount is corrected based on a correction coefficient that is a function of the outside air temperature (T0), and a corrected theoretical makeup water amount (hereinafter referred to as a corrected theoretical makeup water amount) is obtained. Therefore, the water treatment chemical cooling water can be more appropriately proportionally injected with respect to the makeup water by more accurately grasping the makeup water amount and injecting the water treatment chemical proportional to the corrected theoretical makeup water amount into the cooling water 2a. The density in 2a can be managed to a predetermined value.

The purpose of the heat exchanger is to provide a method for injecting water treatment chemicals in an open circulating cooling water system that manages the concentration of the water treatment chemicals in the cooling water to a predetermined concentration, including the correspondence to temperature conditions, economically and simply. Cooling water is circulated and cooled, and the cooling water is cooled by a cooling tower, and a part of the cooling water is blown and makeup water is supplied to keep the concentration ratio of cooling water constant. In an open circulating cooling water system in which a water treatment chemical containing at least one of the prevention component and slime control component is injected in proportion to the amount of makeup water,
Temperature difference ΔT () between the outside air temperature T0, the cooling water temperature, or the temperature T1 of the cooling water (circulation water) from the cooling tower to the heat exchanger and the temperature T2 of the cooling water (circulation water) returning from the heat exchanger to the cooling tower = T2-T1) When the temperature exceeds the set temperature, the water treatment chemical injection method is characterized in that the necessary water treatment chemical is additionally injected.

Furthermore, the injection amount of the water treatment chemical was determined by a function of the temperature factor at the time of the additional injection, and the water treatment chemical was injected by varying the optimal amount. Further, the injection amount of the water treatment chemical injected in proportion to the replenishment water amount is the temperature T1 (° C.) of the cooling water (circulated water) from the cooling tower to the heat exchanger, and returns from the heat exchanger to the cooling tower. The theoretical makeup water amount (M) to the cooling water is determined from the temperature T2 (° C.) of the cooling water (circulating water) according to the following equation (1), and is determined as an amount proportional to the theoretical makeup water amount (M). The water treatment chemical injection method according to any one of the above features is realized. M = ((T2−T1) × c × R / Q) × (N / (N−1)) (Expression 1)
M: Theoretical makeup water volume (m3 / h)
c: Specific heat of water (kcal / kg · ° C)
R: Circulating water volume of cooling water (m3 / h)
Q: latent heat of vaporization of water (kcal / kg)
N: Concentration ratio of cooling water (times)

  In addition, the theoretical makeup water amount is corrected using a correction coefficient that is a function of the outside air temperature T0 (° C.), and an amount of water treatment chemical proportional to the corrected theoretical makeup water amount (corrected theoretical makeup water amount) is injected. This was realized by adopting the structure of the water treatment chemical injection method described above.

  Water treatment chemicals include anticorrosive ingredients, scale preventive ingredients, slime control ingredients, etc., which contain a single ingredient necessary for the injection site, or a mixture of two or more of these ingredients into a single solution There is a one-pack type. These water treatment chemicals are injected into the open circulating cooling water system so as to be managed at a predetermined concentration in order to maintain the effect as a chemical.

  The temperature factor is a target of determination that the effect of the water treatment chemical cannot be maintained only by injecting the water treatment chemical in proportion to the makeup water, that is, the temperature at which it is judged that the water treatment chemical is additionally required. It is a target. For example, the outside temperature T0 of the environment where the cooling tower is installed, the temperature T1 of the cooling water (circulating water) from the cooling tower to the heat exchanger, and the temperature T2 of the cooling water (circulating water) returning from the heat exchanger to the cooling tower , There is a temperature difference ΔT (= T2−T1) between T1 and T2. The magnitude of the heat exchanger load can be estimated from ΔT.

  T0 is a measured value of the outside air temperature, and a real-time measured value near the cooling tower, an average value for a predetermined time, and the like can be used, and these data are sent to the chemical injection control device 6 to check whether or not an additional injection of water treatment chemical is performed. This is used for determining the injection amount and for calculating the corrected theoretical replenishment amount.

  The cooling water temperature T1 is the temperature of the cooling water (circulated water) from the cooling tower to the heat exchanger, the temperature of the cooling water 2a in the cooling tower lower water tank 2d, and the cooling water forward piping from the cooling tower to the heat exchanger. By measuring the cooling water temperature at an arbitrary position in 3e with a water temperature measuring means (a resistance temperature detector, a thermocouple, etc.), the measured value T1 of the cooling water temperature can be obtained.

  The cooling water temperature T2 is the temperature of the cooling water (circulated water) returning from the heat exchanger to the cooling tower, the temperature of the cooling water 2a in the cooling tower upper water tank 2f, and the cooling water returning from the heat exchanger to the cooling tower. The measured value T2 can be obtained by measuring the cooling water temperature at an arbitrary position in the return pipe 3d by means of a water temperature measuring means (temperature measuring resistor, thermocouple, etc.).

  In addition, when the values of T1 and T2 are obtained from the operation information of the open circulating cooling water system, such as when the temperature of the inlet and outlet of the cooling water is measured in real time with a refrigerator, etc., those values are adopted. It doesn't matter. The T1 and T2 data obtained in this way are transmitted to the chemical injection control device 6 and used for the presence or absence of additional injection of the water treatment chemical, determination of the injection amount, and calculation of the corrected theoretical replenishment amount.

  T1 and T2 may each use an average temperature per unit time. For example, from T1 and T2 measured multiple times per hour, and from the average value of each, the average temperature per hour The theoretical makeup water amount may be obtained.

  When deciding whether or not to inject additional water treatment chemicals, there is no superiority or inferiority of each temperature factor, and the temperature factor to be adopted can be selected as appropriate depending on the availability of each cooling tower and taking into account the ease of availability and some errors. it can. Moreover, if all the temperature factors that can be adopted are measured and one of them reaches the judgment standard, there is no problem in additionally injecting the necessary water treatment chemical.

The set temperature of T0, cooling water temperature, and ΔT that requires additional injection of slime control component is a value that is a criterion for determining whether additional injection of slime control component is present, and an optimal value is appropriately set for each cooling water system. Can be set. Specifically, the set temperature of T0 is preferably 25 ° C., for example. Therefore, when T0 is 25 ° C. or higher, the slime control component is injected in addition to the normal water treatment chemical injection proportional to the amount of makeup water. This is because slime grows rapidly when the outside air temperature becomes 25 ° C. or higher.

  The set temperature of T1 is preferably 30 ° C., for example, and when T1 is 30 ° C. or higher, a slime control component is additionally injected similarly to T0. The set temperature of T2 is preferably 35 ° C., for example. When T2 is 35 ° C. or higher, a slime control component is additionally injected in the same manner as T0.

  Furthermore, the set temperature of ΔT is preferably 2 ° C., for example. That is, when ΔT is 2 ° C. or less, the replacement of the cooling water is small, and the slime control component stays in the cooling water for a long time and decomposes to a reduced concentration, so that the effect is not sufficiently exhibited. Therefore, when ΔT is 2 ° C. or less, the slime control component is injected in addition to the normal injection of the water treatment chemical proportional to the amount of makeup water.

  The set temperature of ΔT that requires additional injection of the scale prevention component is a value that serves as a determination criterion for the presence or absence of additional injection of the scale prevention component, and an optimal value can be set as appropriate for each cooling water system. Specifically, ΔT is preferably 7 ° C., for example. That is, when ΔT is 7 ° C. or higher, the load on the heat exchanger is high and the temperature of the heat exchanger heat transfer surface is high, so that the scale tends to precipitate. Therefore, when ΔT is 7 ° C. or higher, the scale prevention component is injected in addition to the normal injection of the water treatment chemical proportional to the amount of makeup water.

  As for the additional injection method, a proportional injection method, a timer injection method, a temporary injection method, etc. can be adopted, whether it is a one-component water treatment chemical, a slime control component, or a single component for preventing scale. .

  The proportional injection method is a method of injecting a certain amount in proportion to the amount of makeup water. If it is a one-pack type water treatment chemical containing a component to be additionally injected, the chemical injection pump 5c of the chemical injection device 5 may be additionally operated. Separately, when additionally injecting slime control components and scale prevention components, a chemical tank and a chemical injection pump for additional injection may be provided, and the chemical injection pump may be operated for a predetermined time in proportion to the amount of replenishment water. .

  The timer injection method is a method of injecting a water treatment chemical into cooling water intermittently using a timer. For example, it is a method of injecting a water treatment chemical by operating a chemical injection pump such as 1 hour per day or 10 minutes every hour, and according to the conditions to be handled, any time interval and any injection time The injection amount can be selected.

  The temporary injection method is a method of temporarily injecting a predetermined amount, for example, 100 mg / l of a water treatment chemical with respect to the retained cooling water amount when the temperature condition exceeds a set temperature. .

  The additional injection amount of the water treatment chemical can be easily realized by adding an injection amount of a predetermined amount as described above when the temperature factor is equal to or higher than the set value. Furthermore, it is possible to vary the injection amount of the water treatment chemical as a function of the temperature of the temperature factor adopted for the set temperature. Thereby, the effect of a water treatment chemical | medical agent can be acquired more appropriately.

For example, when the normal injection amount is B ml and the set temperature C ° C. with respect to the makeup water amount Am ³ , when the additional water treatment agent is additionally injected with D ml, the measurement temperature at the additional injection is E ° C. (E> C, When the temperature is above the set temperature)
Additional injection amount F = D + α (E−C); α can be controlled to increase / decrease the additional injection amount for each temperature exceeding the set temperature by a constant or the like.

  The amount of makeup water may be an actual value measured by a flow meter or a makeup water amount calculated by various methods, but it is simple and economical to use the theoretical amount of makeup water obtained by the above formula (1). It is.

  The specific heat (c) of water in the formula (1) is a value that varies depending on the temperature, but since the error is small, it may be set to 1 kcal / kg · ° C. However, if the specific heat data corresponding to the temperature is input to the chemical injection control device 6 in advance and the specific heat (c) corresponding to the measured temperature (T1, T2, etc.) of the cooling water 2a is used, the theoretical makeup water is more accurately obtained. Can be requested.

  Since the circulating water amount (R) of the cooling water 2a can normally be regarded as constant, the circulating water amount (R) determined as a design value for each open circulating cooling water system may be used. However, a flow meter for measuring the circulating water amount of the circulating water 3a may be installed in the circulation line 3, and the circulating water amount measured by the flow meter can also be used.

  Although the latent heat of vaporization (Q) of water is a constant determined according to the temperature of the cooling water 2a, generally, the temperature of the cooling water is about 30 ° C. 580 Kcal / Kg) can be used. However, in order to further increase the calculation accuracy of the theoretical makeup water amount, the latent heat of vaporization corresponding to the temperature is input in advance, and the latent heat of vaporization of water corresponding to the average value of T1, T2 or T1, T2 etc. (Q ) May be used.

  The cooling water concentration ratio (N) is a constant set as appropriate for each open circulating cooling water system from the management target water quality and the makeup water quality of the cooling water. However, it is also possible to measure the water quality information (electric conductivity and ion concentration) of the cooling water and adopt the value divided by the water quality information of the makeup water as the concentration factor.

Therefore, usually
Makeup water volume (M) =
((T2-T1) × 1 × R / 580) × (N / (N−1)) (Formula 2)
As a matter of course, the theoretical replenishment water amount can be easily obtained.

  That is, the amount of makeup water 4a to the open circulation cooling water system 1 can be grasped by measuring T1 and T2 and obtaining the theoretical makeup water amount from the equation (1) or equation (2).

  Next, a method for correcting the theoretical makeup water amount (M) calculated by the equation (1) or the equation (2) based on the outside air temperature (T0) will be described. The amount of make-up water 4a to the open circulation cooling water system 1 can be grasped as the theoretical make-up water amount (M) from the equation (1) or the equation (2) by measuring T1 and T2. There may be an error between M) and the actual amount of makeup water (actual measurement).

  As a result of earnestly searching for the cause, it was found that there is a correlation between the error and the outside air temperature T0. Therefore, by correcting the theoretical make-up water amount based on a correction coefficient that is a function of the outside air temperature T0 and obtaining the corrected theoretical make-up water amount, the water make-up agent can be grasped more accurately and the water treatment chemical proportional to the corrected theoretical make-up water amount By injecting into the cooling water 2a, the concentration of the water treatment chemical in the cooling water 2a can be more appropriately managed to a predetermined value.

For example, if the correction coefficient that is a function of the outside air temperature (T0) is η,
The corrected theoretical makeup water amount Mt (m ³ / h) taking into account the influence of the outside air temperature (T0) is obtained by the following equation (3).
Mt = η × M (3)

Here, for example, as the correction coefficient (η), the following equation (4) can be used as a linear function of the outside air temperature (T0).
η = a × T0 + b (4)

  For general equipment, the coefficient a may be 0.015 and b may be 0.5. In addition, by calculating the coefficients a and b for each facility, the corrected theoretical makeup water amount can be obtained more accurately. Specifically, the theoretical makeup water amount (M) is compared with the actual measured value of makeup water, and a and b are determined for each facility so as to match. The correction coefficient (η) is not limited to a linear function, but may be a quadratic function or other functions. In short, any function may be used as long as the corrected theoretical makeup water amount having a value closest to the actually measured makeup water amount is obtained based on the outside air temperature (T0).

Further, the corrected theoretical makeup water amount (Mt) can also be calculated by the following equation (5) by performing correction by subtracting the function f (T0) of the outside air temperature (T0) from the theoretical makeup water amount (M). Note that the function f (T0) can be a primary function, a secondary function, or other functions, like the correction coefficient (η).
Mt = M−f (T0) (5)

  Hereinafter, based on an accompanying drawing, the injection method of the water treatment chemical | medical agent which is this invention is demonstrated in detail.

  FIG. 1 is a schematic view of an open circulation cooling water system (one example) to which the water treatment chemical injection method according to the present invention is applied in the case of additionally injecting a one-component water treatment chemical according to a temperature factor.

The open circulating cooling water system 1 is provided with a fan 2e for air cooling the cooling water 2a above the lower water tank 2d for storing the cooling water 2a, an upper water tank 2f for returning the circulating water 3a to the upper part, and a cooling water 2a for blowing water to the lower part. An overflow line 11 has a lower water tank 2d connected to a blow pipe 2c that discharges as 2g, and discharges excess cooling water 2a as overflow water 2b so that the water level of the lower water tank 2d of the cooling tower 2 does not exceed a certain level. A cooling tower 2 provided;
Connected to the lower water tank 2d, the cooling water 2a (circulated water 3a) is sent to a heat exchanger 3c such as a refrigerator by driving the circulating pump 3b, and passes through a heat exchanger 3c and a heat exchanger 3c. A cooling water return pipe 3d for returning the exchanged cooling water 2a (circulation water 3a) to the cooling tower 2, and a circulation line 3 including a heat exchanger 3c such as a refrigerator,
Supply water 4a connected to the cooling tower 2 to maintain the water level of the lower water tank 2d when the cooling water 2a decreases or to perform forced blow when the concentration rate of the cooling water 2a increases. Supply line 4 for injecting
It comprises a water treatment chemical injection device 8 for injecting a one-part water treatment chemical proportional to the theoretical replenishment water amount into the cooling water 2a.

  The replenishment line 4 is connected to a replenishment pipe 4c inserted into the cooling tower 2 with a ball tap 4e linked to the height of the water surface of the lower water tank 2d, and a line for replenishing the replenishment water 4a as needed when the cooling water 2a decreases. The forced replenishment valve 4g is opened when the concentration rate of the cooling water 2a rises to a set value or more, and a forced replenishment line 4f for forcibly replenishing the cooling water 2 to the cooling tower 2 is provided.

  The cooling water 2a of the cooling tower 2 is provided with an electric conductivity meter 7 for measuring the electric conductivity of the cooling water 2a. When the electric conductivity of the cooling water 2a exceeds a set value, the forced replenishment valve 4g By opening and replenishing the replenishing water 4a and discharging a part of the cooling water as the overflow water 2b, the concentration rate of the cooling water 2a is maintained at a predetermined value.

  The water treatment chemical injection device 8 includes a temperature sensor (outward) 10, a temperature sensor (return) 9, a chemical injection device 5, and a chemical injection control device 6. An outside air temperature sensor 12 is added as necessary.

  The temperature sensor (outward) 10 is provided in the cooling water outgoing pipe 3e, and measures the temperature T1 (° C.) of the cooling water 2a from the cooling tower 2 toward the heat exchanger 3c. The temperature T1 measured by the temperature sensor (outward) 10 is sent to a medicine injection control device 6 described later.

  The temperature sensor (return) 9 is provided in the cooling water return pipe 3d, and measures the temperature T2 (° C.) of the cooling water 2a that returns from the heat exchanger 3c to the cooling tower 2. The temperature T2 measured by the temperature sensor (return) 9 is also sent to the medicine injection control device 6 described later.

  The temperature sensors (return) 9 and (outward) 10 may be inserted into the pipe or contacted (attached) to the pipe. When contacting the piping, it is desirable to cover the piping portion including the temperature sensor with a heat insulating material in order to increase the measurement accuracy of T1 and T2. In the case of the system in which the temperature sensors (return) 9 and (out) 10 are brought into contact with the pipe, the open circulating cooling water system 1 can be installed without stopping, and the amount of makeup water can be grasped easily and at low cost. it can. On the other hand, when the flow rate of the makeup water 4a is measured by installing a flow meter as in the prior art, the open circulating cooling water system must be stopped and an expensive pulse transmission flow meter must be installed.

  The chemical injection device 5 includes a tank 5b for storing the one-component water treatment chemical 5a, a chemical injection line 5d that communicates from the tank 5b to the lower water tank 2d, and a single-component water treatment chemical 5a through the chemical injection line 5d. It consists of a chemical injection pump 5c for injecting into the lower water tank 2d.

  The medicinal pump 5c is not particularly limited as long as it is a pump capable of transferring a fluid. The chemical injection pump 5c is driven based on a chemical injection pump operation signal 6e output from a chemical injection control device 6 to be described later, and an amount proportional to the amount of replenishing water, and the one-pack type water treatment chemical 5a to be additionally injected are described above. It is controlled by the chemical injection control device 6 so as to be injected into the open circulation cooling water system 1.

  The medicinal injection control device 6 has measured values T1, T2, specific heat of water (c), circulating water amount (R), latent heat of water evaporation (Q), cooling water set in advance or measured. Based on the concentration ratio (N) and the outside air temperature (T0) measured as necessary, the theory for the open circulation cooling water system 1 according to any of the above formulas (1) to (3) and (5) An amount of supplementary water (M) or a corrected theoretical amount of supplementary water (Mt) is obtained, and a chemical injection pump operation signal 6e so as to inject the one-part water treatment chemical 5a in proportion to the obtained amount of supplementary water into the open circulation cooling water system 1. Is output to the chemical injection pump 5c.

  As a result, the chemical injection pump 5c injects the one-component water treatment chemical 5a in proportion to the obtained replenishing water amount into the open circulation cooling water system 1, and the temperature conditions such as T0, T1, T2, and ΔT are set temperatures. When the pressure exceeds the value, by appropriately increasing the injection amount, the one-part water treatment chemical 5a of the open circulation cooling water system 1 is maintained and managed at a truly necessary concentration.

  In FIG. 1, the chemical injection control device 6 has a function of outputting a forced supply signal 6f for opening and closing the forced supply valve 4g based on the electrical conductivity data 7a from the electrical conductivity meter 7. As a separate device, it may be separated from the chemical injection control device 6.

  FIG. 2 is a schematic view of an open circulating cooling water system (one example) to which the water treatment chemical injection method according to the present invention, in which a scale preventing component or / and a slime control component is separately added to the open circulating cooling water system, is applied.

  The open circulating cooling water system 13 is different from the open circulating cooling water system 1 of FIG. 1 in that the water treatment chemical 5e, the temperature sensor (out) 10a, and the temperature sensor (return) 9a in the tank 5b are installed in different locations. There is no change in the configuration other than the point having two devices, that is, the point having the additional medicine injection device 14 and the second medicine addition device 15. Therefore, the same reference numerals in FIG. 2 as those in FIG. 1 are omitted because they have the same devices and functions.

  The water treatment chemical 5e may not include the water treatment chemical injected by the additional chemical injection device 14 and the second additional chemical injection device 15, or may include them to form a one-pack type water treatment chemical 5a. However, the water treatment chemical to be added is performed from the additional chemical injection device 14 and the second additional chemical injection device 15. Thereby, when the temperature condition exceeds the set temperature, the necessary water treatment chemicals can be injected as the additional water treatment chemicals 14a and 15a, which is economical.

  For example, the additional water treatment chemical 14a is a slime control component, and the additional water treatment chemical 15a is a scale prevention component.

  The installation locations of the temperature sensor (out) 10a and the temperature sensor (return) 9a are the lower water tank 2d and the upper water tank 2f of the cooling tower 2, respectively, and T1 and T2 can be measured more easily.

  The additional chemical injection device 14 passes through the tank 14b for storing the additional water treatment chemical 14a, the additional chemical injection line 14d communicating from the tank 14b to the lower water tank 2d, and the additional water treatment chemical 14a through the additional chemical injection line 14d. It consists of a chemical injection pump 14c for injecting into the lower water tank 2d.

  The medicinal pump 14c is not particularly limited as long as it is a pump capable of transferring a fluid. The medicinal pump 14c is driven based on the medicinal pump operation signal 6a output from the medicinal control device 6 described above, and an additional water treatment chemical 14a (for example, a slime control component) in an amount to be additionally injected depending on temperature conditions. Is controlled by the chemical injection control device 6 so as to be injected into the open circulation cooling water system 13.

  The second additional chemical injection device 15 includes a tank 15b that stores the additional water treatment chemical 15a, an additional chemical injection line 15d that communicates from the tank 15b to the lower water tank 2d, and an additional water treatment chemical 15a that is used as the additional chemical injection line. It consists of a medicine pump 15c for injecting into the lower water tank 2d through 15d.

  The medicinal pump 15c is not particularly limited as long as it is a pump capable of transferring a fluid. The medicinal pump 15c is driven based on the medicinal pump operation signal 6b output from the medicinal control device 6 described above, and an additional water treatment chemical 14a to be additionally injected according to temperature conditions is supplied to the open circulating cooling water system 13. It is controlled by the medicine injection control device 6 so as to be injected into

  The amount of makeup water actually measured in a cooling tower in actual operation (actual measurement), the amount of theoretical makeup water (M) obtained from equation (2), and the corrected theoretical makeup water amount (Mt) obtained from equations (3) and (4) ) Will be described with reference to FIG.

FIG. 3 is a diagram showing the relationship between the actually measured amount of makeup water, the theoretical makeup water amount, and the corrected theoretical makeup water amount. The horizontal axis in FIG. 3 is the actually measured value (m ³ / h) of the make-up water amount, and the vertical axis is the calculated make-up water amount (m ³ / h) obtained from the equations (2), (3), and (4). . ◇ is the theoretical makeup water volume obtained from equation (2), and ▲ is the theoretical makeup water volume (◇) obtained from equation (2) based on the outside air temperature (T0), corrected by equations (3) and (4). This is the corrected theoretical makeup water amount.
However, the coefficient a = 0.015 and b = 0.5 in Formula (4) were used.

  If the measured amount of make-up water matches the calculated amount of make-up water calculated from equations (2), (3), and (4), ◇ and ▲ are plotted on the linear function y = x. The Rukoto. However, the theoretical amount of replenishment water ◇ obtained from the equation (2) that is not corrected by the outside air temperature is a slightly higher value overall.

  Accordingly, when the water treatment chemical is injected based on the theoretical replenishment water amount, the concentration of the water treatment chemical is slightly higher than the predetermined concentration. However, even if the injection amount of the water treatment chemical is determined based on the theoretical replenishment water amount obtained by the formulas (1) and (2), there is no shortage of the water treatment chemical and the function of the water treatment chemical is exhibited. There is no problem in the actual operation of the open circulation cooling water system.

  On the other hand, it can be seen that the plotted corrected theoretical makeup water amount ▲ shows a value very close to the actual makeup water amount (actual measurement) and is corrected by a function of the outside air temperature (T0). It can be seen that the method of correcting the theoretical makeup water amount using) is effective.

  That is, by determining the injection amount of the water treatment chemical based on the above-described corrected theoretical makeup water volume, it is possible to obtain an effect if the supplementary water proportional injection is performed. It is possible to easily adjust the concentrations of the scale prevention component, slime control component, and the like to appropriate values.

  Also, under certain temperature conditions, the scale prevention component and slime control component are insufficient, so by adding additional water treatment chemical according to the present invention, the concentration of the water treatment chemical is adjusted to an appropriate concentration that can always exert its effect. It becomes possible to do.

It is the schematic of the open circulation cooling water system (an example) to which the injection | pouring method of the water treatment chemical | medical agent which is this invention is applied in the case of injecting | pouring one liquid type water treatment chemical | medical agent according to a temperature factor. It is the schematic of the open circulation cooling water system (an example) to which the injection | pouring method of the water treatment chemical | medical agent which is this invention which additionally injects a scale prevention component or / and a slime control component separately to an open circulation cooling water system is applied. It is a figure which shows the relationship between the actual amount of makeup water, the theoretical makeup water amount, and the correction theoretical makeup water amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Open circulation cooling water system 2 Cooling tower 2a Cooling water 2b Overflow water 2c Blow piping 2d Lower water tank 2e Fan 2f Upper water tank 2g Blow water 3 Circulation line 3a Circulating water 3b Circulation pump 3c Heat exchanger 3d Cooling water return piping 3e Cooling water going Pipe 4 Supply line 4a Supply water 4c Supply pipe 4e Ball tap 4f Forced supply line 4g Forced supply valve 5 Chemical injection device 5a Water treatment chemical 5b Tank 5c Chemical injection pump 5d Chemical injection line 5e Water treatment chemical 6 Chemical injection control device 6a Chemical injection Pump operation signal 6b Chemical injection pump operation signal 6e Chemical injection pump operation signal 6f Forced replenishment signal 7 Electrical conductivity meter 7a Electrical conductivity data 8 Water treatment chemical injection device 9 Temperature sensor (return)
9a Temperature sensor (return)
10 Temperature sensor (out)
10a Temperature sensor (out)
11 Overflow line 12 Outside air temperature sensor 13 Open circulation cooling water system 14 Additional chemical injection device 14a Additional water treatment chemical 14b Tank 14c Pump 14d Additional chemical injection line 15 Second additional chemical injection device 15a Additional water treatment chemical 15b Tank 15c Chemical injection pump 15d additional drug injection line

Claims (6)

  The cooling water is circulated and supplied to the heat exchanger and the cooling water is cooled by the cooling tower, and a part of the cooling water is blown and makeup water is supplied to keep the concentration ratio of the cooling water constant. In an open circulating cooling water system in which a water treatment chemical containing at least one of anticorrosive ingredients, scale preventing ingredients, and slime control ingredients is injected in proportion to the amount of makeup water, the outside air temperature T0 or cooling water (circulating water) The water treatment chemical injection method is characterized by additionally injecting a water treatment chemical containing a slime control component when the temperature of) is equal to or higher than a set temperature.   The cooling water is circulated and supplied to the heat exchanger and the cooling water is cooled by the cooling tower, and a part of the cooling water is blown and makeup water is supplied to keep the concentration ratio of the cooling water constant. Cooling water from the cooling tower to the heat exchanger in an open circulating cooling water system in which a water treatment chemical containing at least one of the anticorrosive component, scale preventing component and slime control component is injected in proportion to the amount of makeup water When the temperature difference ΔT (= T2−T1) between the temperature T1 of the (circulated water) and the temperature T2 of the cooling water (circulated water) returning from the heat exchanger to the cooling tower is equal to or lower than the set temperature, water containing a slime control component A method for injecting a water treatment agent, wherein the treatment agent is additionally injected.   The cooling water is circulated and supplied to the heat exchanger and the cooling water is cooled by the cooling tower, and a part of the cooling water is blown and makeup water is supplied to keep the concentration ratio of the cooling water constant. Cooling water from the cooling tower to the heat exchanger in an open circulating cooling water system in which a water treatment chemical containing at least one of the anticorrosive component, scale preventing component and slime control component is injected in proportion to the amount of makeup water When the temperature difference ΔT (= T2−T1) between the temperature T1 of the (circulated water) and the temperature T2 of the cooling water (circulated water) returning from the heat exchanger to the cooling tower is equal to or higher than the set temperature, water containing a scale prevention component A method for injecting a water treatment agent, wherein the treatment agent is additionally injected.   The method for injecting a water treatment chemical according to any one of claims 1 to 3, wherein the injection amount of the water treatment chemical to be additionally injected is determined by a function of a temperature factor at the time of additional injection. The amount of water treatment chemical injected in proportion to the amount of makeup water is the temperature T1 (° C.) of the cooling water (circulated water) from the cooling tower to the heat exchanger, and the cooling water returning from the heat exchanger to the cooling tower. The amount of theoretical makeup water (M) to the cooling water is obtained from the temperature T2 (° C.) of (circulated water) according to the following equation (1), and is determined as an amount proportional to the amount of theoretical makeup water (M). The method for injecting a water treatment chemical according to any one of claims 1 to 4, wherein:
M = ((T2−T1) × c × R / Q) × (N / (N−1)) (Expression 1)
M: Theoretical makeup water volume (m3 / h)
c: Specific heat of water (kcal / kg · ° C)
R: Circulating water volume of cooling water (m3 / h)
Q: latent heat of vaporization of water (kcal / kg)
N: Concentration ratio of cooling water (times)   The theoretical makeup water amount is corrected using a correction coefficient that is a function of the outside air temperature T0 (° C.), and an amount of water treatment chemical proportional to the corrected theoretical makeup water amount (corrected theoretical makeup water amount) is injected. The method for injecting a water treatment chemical according to claim 5.

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