JP2010253360A - Method and apparatus for treating cooling water of refrigerator/cold and warm water machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively and surely prevent scale deposition without using chemicals and to perform a high concentration operation. <P>SOLUTION: In a cooling tower 12 for sending cooling water to a refrigerator/cold and warm water machine 10 and cooling discharged cooling water from the refrigerator/cold and warm water machine, a filtration apparatus 14 for introducing a part of the cooling water cooled in the cooling tower and performing the treatment of at least one of fine filtration and general filtration, and a cooling water circulation pump 16 provided between the cooling tower and the filtration apparatus are provided. By treating a part of the circulated cooling water of the refrigerator/cold and warm water machine 10 by at least one of the fine filtration and the general filtration, granular scale components in the cooling water are removed beforehand. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a cooling water treatment method and apparatus for a refrigerator or a cold / hot water machine (hereinafter referred to as a freezer / cooling / hot water machine), and more particularly, a cooling water system water treatment method and treatment apparatus for a freezer / cooling / hot water machine. Therefore, the present invention relates to a cooling water treatment method and apparatus that can realize a highly concentrated operation of cooling water by preventing precipitation of scales, particularly silica-based scales, and can reduce the cost of makeup water. .

  Conventionally, as a technique for preventing precipitation of scale components, in addition to general water treatment methods such as cooling water concentration management and addition of crystal growth inhibitors, crystallization methods, membrane separation by reverse osmosis membranes (NF membrane, RO membrane), Various treatment methods have been proposed such as magnetic field treatment, electrolysis equipment, metal elution, electrolysis, ultrasonic treatment, etc., but cooling water treatment method that suppresses environmental burden and stably provides scale precipitation prevention effect at low cost・ There is no highly concentrated operation method.

  Conventionally, in general, solid-liquid separation treatment in cooling water treatment has been recognized as an auxiliary treatment such as turbidity use or ultrafiltration pretreatment, and it has been completely recognized that it has an effect of preventing scale precipitation. Not. Conventionally, it is intended to remove suspended substances and sludge (see, for example, Patent Document 1), and has no effect of preventing scale precipitation (see, for example, Patent Document 2). Also in RO membrane treatment, a membrane such as an MF membrane (microfiltration membrane) used in the present invention is used as a prefilter for removing SS (floating matter) for preventing RO membrane blockage (for example, , See Patent Document 3), the effect of preventing the precipitation of scale is not expected by a single treatment.

Japanese Patent No. 3512108 (first page) Japanese Patent Laid-Open No. 2002-54894 (2nd page, FIG. 1) Japanese Patent No. 3731555 (second page, FIG. 1)

  The problem to be solved is that the environmental load is low, that is, the treatment of cooling water in refrigerators / cooling / hot water machines that does not use chemicals and that prevents high-concentration operation at low cost and reliably prevents scale deposition. The method and apparatus are not developed.

  The main feature of the present invention is to prevent precipitation as crystals and realize high concentration operation by collecting and removing scale components in the water as particles in the water. The present invention is particularly effective for silica which is difficult to prevent scale precipitation even when chemicals are used. That is, this invention is a processing method and apparatus characterized by processing cooling water with the filtration apparatus which is a scale component particle removal apparatus in a cooling water system, By collecting the particle | grains of precision-general filtration level, Achieve the goal.

  The cooling water treatment method of the refrigerator / cooling / heating device of the present invention is a method of treating particles in the cooling water by treating a part of the circulating cooling water of the refrigerator / cooling / heating device with at least one of microfiltration and general filtration. It is characterized by removing the scale component before aggregation and precipitation occur.

  In this method, it is desirable to remove particulate scale components having a particle size of 0.01 μm, preferably 0.1 μm or more. Moreover, it is desirable to treat 0.03 to 5% of the circulating cooling water amount.

  In addition, the cooling water treatment device for the refrigerator / cooling / heating device of the present invention is a cooling tower for sending cooling water to the refrigerator / cooling / heating device and cooling the exhaust cooling water from the refrigerator / cooling / heating device. And a filtration device for introducing at least one of microfiltration and general filtration by introducing a part of the cooling water cooled in the cooling tower. In addition, it is preferable to use the microfiltration apparatus which removes 0.01 micrometer or more of particulate scale components as a filtration apparatus.

Since this invention is comprised as mentioned above, there exist the following effects.
(1) By collecting and removing scale components as particles in the water, precipitation as crystals can be prevented and a high concentration operation can be realized.
(2) The objective can be achieved by an inexpensive process with precision to general filtration level.
(3) It has a high effect on silica, which is difficult to prevent scale precipitation even when chemicals are used.
(4) Since a water-saving effect can be obtained without using chemicals, it is possible to reduce environmental costs and reduce running costs.
(5) Pre-processing such as prefilter installation and chemical introduction is not always necessary, and the apparatus can be downsized and the processing can be simplified.

FIG. 1 is a schematic configuration diagram of a cooling water treatment device of a refrigerator / cooling / heating device according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram of the circulating cooling water system used in the experimental example. FIG. 3 is a schematic configuration diagram of a cooling water treatment device of a refrigerator / cooling / heating device according to the second embodiment of the present invention.

  A part of circulating cooling water is treated with at least one of microfiltration and general filtration for the purpose of preventing the precipitation of scale of cooling water system, enabling high concentration operation of cooling water and reducing the cost of makeup water This was realized by previously removing the particulate scale component in the cooling water.

  Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications. FIG. 1 is a schematic configuration diagram of a cooling water treatment device for a refrigerator / cooling / heating device according to a first embodiment of the present invention.

  Reference numeral 10 denotes a refrigerator / cooling / heating device, which sends cooling water from a cooling tower (cooling tower) 12 to cool the exhaust cooling water from the refrigerator / cooling / heating device 10 with the cooling tower 12. To do. 14 is a filtration device for introducing a part of the cooling water cooled by the cooling tower 12 and performing at least one of the microfiltration and the general filtration. A cooling water circulation pump 16 is provided between the cooling tower 12 and the filtration device 14. 18 is cooling water, and 20 is a fan.

  In the filtration device 14, at least one of a microfiltration membrane having a filtration accuracy of 0.01 μm or more and a general filtration membrane having a filtration accuracy of 25 μm is used.

  In the apparatus configured as described above, the particulate scale component in the cooling water is removed in advance by treating a part of the circulating cooling water of the refrigerator / cooling / hot water machine 10 with at least one of microfiltration and general filtration. To do.

In this case, it is desirable to remove particulate scale components having a particle size of 0.1 μm or more. The particulate scale component having a particle size of less than 0.01 μm is relatively stably suspended in water and does not tend to crystallize and precipitate immediately. It can be removed after becoming.
Moreover, it is desirable to treat 0.03 to 5% of the circulating cooling water amount. When processing less than 0.03% of the circulating cooling water amount, the processing water amount is too small to sufficiently remove the particulate scale component in the cooling water. Moreover, when processing the amount exceeding 5% of the circulating cooling water amount, the circulating pump and the filtration device become too large for the effect. By setting the upper limit to 5% of the circulating cooling water amount, a sufficient effect can be obtained.
If the filtration accuracy of the membrane used and the treatment rate of the cooling water are within the range of these conditions, the effect of preventing scale precipitation can be expected, but the precipitation of scale crystals may depend on the cooling water quality and the operating conditions of the refrigerator / cooling / heating machine. Since the degree is different, it is possible that the effect of preventing scale precipitation can be obtained even when the above conditions are not met.

In circulating cooling water, scale components such as calcium, magnesium, and silica are initially dissolved in water as ions, but the scale component is evaporated by the water in the cooling water evaporating with the operation of the refrigerator / cooling / heating device. The concentration becomes high. Along with this, the scale component changes from a state dissolved in water to an insoluble substance (floating in water as fine particles), and finally crystallizes and precipitates as scale inside the machine. In the conventional separation technique, the precipitation of the scale crystal is prevented by removing it in the form of ions, whereas in the present invention, the process of growing as a crystal, that is, in the state of floating in the water as charged fine particles. Collect and remove. Therefore, like the conventional membrane separation technique, the pretreatment for promoting aggregation can be omitted, and the processing apparatus can be simplified.
Note that the present technology is effective in preventing precipitation of scale components even in water other than cooling water as long as it is a treatment of water that causes concentration of dissolved components accompanying water evaporation.

  In the present invention, cooling water is treated in a cooling water system by a filtration device that is a scale component precipitation prevention treatment device, thereby enabling high concentration operation. Moreover, this invention is suitable for the cooling water system | strain using makeup water with many scale components, such as a silica and calcium. In addition, the filtration device which is a scale component precipitation prevention treatment device used in the present invention is only required to collect particles having a certain particle diameter or more, and a filtration method using a filter medium, a fiber filtration method, a membrane filtration method, a centrifugal separation method method. Such devices can be used. A specific example of the apparatus is a filtration apparatus using a hollow fiber membrane (refer to FIG. 1 for the apparatus flow). In this case, any system of internal pressure filtration / external pressure filtration, suction filtration, cross flow filtration / total amount filtration is applicable. In addition, the filtration device can be provided with a water flow recovery function by washing the membrane or the like.

  The equipment of the filtration device may be installed by providing a bypass line in the cooling water system, or may be installed by providing another system in the cooling tower. Desirably, water is taken from the secondary side of the cooling water system and the treated water is returned to the primary side, but a system that can circulate to the water receiving tank of the cooling tower may be provided. Moreover, you may use together a scale component inhibitor, an algae inhibitor, a slime inhibitor, an anti- Legionella agent, and a corrosion inhibitor as needed. Furthermore, it can be used in combination with a sterilizer (hydrogen peroxide / ozone generation, ultraviolet irradiation, metal elution, etc.). In order to stably obtain the effect of preventing the precipitation of scale, it is preferable to use cooling water concentration management by an automatic flow device in combination. In addition, a pretreatment step can be provided for the purpose of aggregating the collected material and stabilizing the filtration device.

Cooling capacity: 200 RT general air conditioning equipment was used. The treatment frequency of the filtration device, which is a water treatment device, was 0.6% of the amount of circulating water. Electrical conductivity: 13 mS / m, calcium hardness: 15 mg CaCO ₃ / L, ionic silica concentration: 48 mg SiO ₂ / L, chloride ion concentration: 10 mg Cl / L groundwater is used as make-up water, and concentration control is performed by conductivity monitoring. The upper limit of conductivity was controlled as 45 mS / m. The increase in the refrigerant temperature of the condenser and the cooling water outlet temperature difference (LTD) during the peak period of July to August was 0.15 ° C.
Further, in the water analysis results, neither calcium hardness nor ionic silica concentration showed a decrease in concentration indicating scale precipitation, and scale adhesion inside the watering tank / filler and cooling tower was not confirmed by visual observation. A hollow fiber membrane having a filtration accuracy of 0.85 μm was used as the filtration membrane in the filtration device.

Cooling capacity: 210RT general air conditioning equipment was used. The treatment frequency of the filtration device, which is a water treatment device, was 0.1% of the amount of circulating water. Electrical conductivity: 13 mS / m, calcium hardness: 15 mg CaCO ₃ / L, ionic silica concentration: 48 mg SiO ₂ / L, chloride ion concentration: 10 mg Cl / L groundwater is used as make-up water, and concentration control is performed by conductivity monitoring. The upper limit of conductivity was controlled as 45 mS / m. The rise in the refrigerant temperature of the condenser and the cooling water outlet temperature difference (LTD) during the peak period from July to August was 0.22 ° C.
Further, in the water analysis results, neither calcium hardness nor ionic silica concentration showed a decrease in concentration indicating scale precipitation, and scale adhesion to the inside of the watering tank / filler and the cooling tower was not confirmed by visual observation. A hollow fiber membrane having a filtration accuracy of 0.1 μm was used as the filtration membrane in the filtration device.

Comparative Example 1

Cooling capacity: 210RT general air conditioning equipment was used. Calcium hardness: 15 mg CaCO ₃ / L, ionic silica concentration: 48 mg SiO ₂ / L, chloride ion concentration: 10 mg Cl / L groundwater is used as make-up water, water treatment with ceramic balls and concentration management by conductivity monitoring are performed to conduct electricity The upper limit of the rate was controlled as 36 mS / m. The increase in the refrigerant temperature of the condenser and the cooling water outlet temperature difference (LTD) during the peak period of July to August was 0.56 ° C. In addition, precipitation of scale inside the cooling tower was observed.

Next, an experiment was performed using the apparatus shown in FIG. 22 is a water tank, 24 is a circulation pump, 26 is a filter, 28 is a glass tube, and 30 is a heater.
The scale adhesion prevention effect was evaluated using the miniature model of the circulating cooling water system shown in FIG. The cooling water system used had a water volume of 5 L, and a glass tube 28 having an inner diameter of 30 mm was passed through the heater 30 to form a heat load portion. The make-up water was adjusted to a calcium hardness of 5000 mg CaCO ₃ / L by adding calcium chloride to city water, and the flow rate of circulating water was 5 L / min. The circulating water temperature was adjusted to 35 ° C., and after 210 hours of operation, the glass tube 28 was removed, dried and weighed, and the amount of scale adhered was determined from the weight difference before and after the test. The results are shown in Table 1.

  It can be seen from Table 1 that the amount of scale adhesion decreases by reducing the filtration accuracy or / and increasing the filtration frequency.

  FIG. 3 shows an apparatus according to a second embodiment of the present invention. As shown in FIG. 3, the circulation pump can be omitted.

  In the refrigerator / cold hot / cold water machine, by preventing the precipitation of scale, it is possible to reduce the makeup water cost.

DESCRIPTION OF SYMBOLS 10 Refrigerator / Cold / Hot Water Machine 12 Cooling Tower 14 Filtration Device 16 Circulation Pump 18 Cooling Water 20 Fan 22 Water Tank 24 Circulation Pump 26 Filter 28 Glass Tube 30 Heater

Claims (5)

  Refrigeration characterized in that a part of the circulating cooling water of the refrigerator / cooling / warm water machine is treated in advance by at least one of microfiltration and general filtration, so that the particulate scale components in the cooling water are removed in advance before precipitation. Of cooling water for water heaters and hot / cold water heaters.   The processing method of the cooling water of the refrigerator / cooling / heating device according to claim 1, wherein a particulate scale component of 0.01 μm or more is removed.   The processing method of the cooling water of the refrigerator / cooling / heating device according to claim 1 or 2, wherein 0.03 to 5% of the circulating cooling water amount is treated.   In the cooling tower for sending the cooling water to the refrigerator / cooling / hot water machine and cooling the exhaust cooling water from the refrigerator / cooling / heating machine, a part of the cooling water cooled by the cooling tower is introduced and microfiltration and A cooling water treatment apparatus for a refrigerator or a hot and cold water machine, comprising a filtration device for performing at least one of general filtration treatments.   5. The cooling water treatment device for a refrigerator / cooling / heating device according to claim 4, wherein the filtration device is a microfiltration device for removing particulate scale components of 0.01 μm or more.

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