JP2008246471A - Treatment method of circulation type cooling water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for efficiently and surely suppressing the generation of fungi and/or algae in circulation cooling water without using a chemical. <P>SOLUTION: A solid matter P uniformly containing a photocatalyst with a function capable of renewing a surface to a light source at all times by the stream of cooling water is disposed inside a tower of a cooling tower 1, the cooling water is brought into contact with the solid matter P, and the decomposition treatment of an organic compound is performed. The solid matter P is composed of a substance for which a titanium oxide is deposited to crystalline quartz, glass powder and the clay mineral of a plasticizer which are kneaded, molded and calcined. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is mainly applied to the treatment of circulating cooling water used in water-cooled air conditioning equipment, and more particularly relates to means for inhibiting the growth of fungi and / or algae in the water, causing drainage and air pollution. It relates to a technology that replaces the drug input.

  A typical cooling water circulation system according to a general example is shown in FIG. 10. First, water discharged from the feed pipe 2 from the lower side of the cooling tower 1 is pressurized by a circulation pump 3 and air-conditioned. It is transported to the heat exchanger 4 attached to the machine. The cooling water heated to the high temperature by the heat exchanger 4 returns to the upper side of the cooling tower 1 from the return pipe 5 and comes into contact with air. Here, a part of the water is evaporated, the temperature of the cooling water is lowered by the latent heat of evaporation, and the water is used again for cooling. In general, city water, industrial water, groundwater, and the like are used as makeup water for the cooling water system.

  In such a cooling water system, a part is lost due to evaporation, but from the viewpoint of lack of water resources and effective use, most of the water is circulated to reduce the amount of cooling water used. Due to the advanced use of this cooling water, salts and the like are concentrated, the water quality is deteriorated, and fungi and algae are easily propagated. Moreover, when these fungi, algae, and microorganisms are combined with dust in the air, it becomes an environment in which a viscous substance called slime is easily generated.

  Thus, when slime is generated and adheres to the cooling tower 1 and the circulation pipe, not only the heat exchange rate is lowered, but also the pipe is blocked to cause deterioration of water flow. For this reason, a solid medicine is charged and a chemical injection device 6 as ancillary equipment is provided, and a medicine such as a disinfectant and an algicide is added.

  For example, hypochlorous acid or hypochlorite is used as the disinfectant and algicide. As a sterilization method, an ozone sterilization apparatus has been proposed (Patent Document 1). For slime, for example, chlorine or a chlorine compound is used (Patent Document 2).

  On the other hand, the cooling tower 1 is always replenished with fresh water from the make-up water introduction pipe 7 in order to supplement the amount corresponding to the water discharged to the outside of the tower by evaporating water or splashed water. The impurities in the cooling water are concentrated by long-time operation. In addition, dust and harmful substances in the atmosphere are mixed into the circulating water due to the outside air being taken into the tower by the blower 8, and in order to eliminate this, a certain amount of water is blown as the blow water 9 It is discharged out of the system and replaced with new water.

  However, this waste water contains a large amount of chemicals added to sterilization and algaecidal, and if discharged as it is, it will cause environmental pollution.

Therefore, the waste water is neutralized with chemicals. However, these have the problem of requiring a lot of time and cost. Therefore, in the treatment of circulating cooling water, a simpler and cheaper means that can solve problems such as environmental burden, labor associated with adding chemicals, cost, and danger of handling chemicals is desired. It was.
Japanese Patent Laid-Open No. 11-347563 JP-A-53-028948

  The present invention solves the above-mentioned problems and is a simple and inexpensive circulation capable of suppressing generation of fungi and / or algae in a cooling water system without requiring the addition of a sterilizing and / or algicidal agent. An object of the present invention is to provide a method for treating the cooling water.

  As a result of intensive research to solve the above problems, the present inventors provide a cooling tower with a substance capable of decomposing organic matter by light energy. Or the means which suppresses generation | occurrence | production of algae was discovered, and it came to complete this invention based on this knowledge.

  Claim 1 of the present application is a water treatment method for suppressing the generation of fungi and / or algae in a circulating cooling water system, and the surface of the light source can always be updated by the flow of cooling water. A solid material containing a homogeneous photocatalyst having various functions is placed in the tower of a cooling tower, and cooling water is brought into contact with the solid material to decompose organic matter.

  Claim 2 of the present application is characterized in that as a solid material having a function capable of constantly updating the surface with respect to the light source, a solid material containing a substance in which titanium oxide is supported on crystalline quartz is provided.

  Claim 3 of the present application kneads and molds a substance in which titanium oxide is supported on crystalline quartz, a glass powder and a clay mineral of plasticizer as a solid having a function capable of constantly updating the surface with respect to the light source. , 600 ° C. or higher, preferably 900 to 1200 ° C. or lower.

  Claim 4 of the present application is characterized in that a light source including ultraviolet rays such as sunlight is used to suppress generation of fungi and / or algae.

  Claim 5 of this application arrange | positions the apparatus which continuously measures and monitors the fungi and / or algae in water in the circulation system of the cooling water, and automatically collects, filters, extracts, refrigerates, and centrifuges the sample water. It is characterized by the fact that it was performed in

  According to the circulating cooling water treatment method according to claim 1 of the present application, the solid matter containing the photocatalyst that decomposes the organic matter has the function of constantly updating the surface with respect to the light source by the water flow of the cooling water. Therefore, generation of fungi and / or algae can be suppressed without using a drug, and even if it already exists, it can be decomposed and removed. In addition, since there is no use of chemicals, blow water discharged outside the system does not cause adverse effects on the environment.

  According to the method for treating circulating cooling water according to claim 2 of the present application, as a solid having a function capable of constantly updating the surface with respect to the light source, a solid including a substance in which titanium oxide is supported on crystalline quartz Therefore, the organic substance decomposition function can be sufficiently exerted by the highly transparent solid substance, and the generation of fungi and / or algae can be reliably suppressed.

  According to the method for treating circulating cooling water according to claim 3 of the present application, a substance in which titanium oxide is supported on crystalline quartz as a solid having a function capable of constantly updating the surface with respect to a light source, and glass powder And a plasticizer clay mineral, and a solid material fired in the region of 600 ° C. or higher, preferably 900 to 1200 ° C. or lower. Can also be sustained.

  According to the method for treating circulating cooling water according to claim 4 of the present application, in order to suppress the generation of fungi and / or algae, a light source containing ultraviolet rays such as sunlight is used, so that the generation of fungi and / or algae is efficiently performed. It can be surely suppressed.

  According to the circulating cooling water treatment method according to claim 5 of the present application, since the fungi and / or algae in the cooling water are continuously measured and monitored, maintenance and management of the cooling water can be performed accurately.

  Hereinafter, with reference to FIGS. 1 to 9, FIG. 1 shows an example of a circulation device that implements the method for treating circulating cooling water according to the present invention. The circulation device is applied to an air conditioning / industrial cooling facility equipped with a refrigerator, and includes a cooling tower 1 and a heat exchanger 4 for cooling cooling water (hereinafter referred to as “circulated water”). Configured. In the figure, components common to those in FIG. 10 are denoted by the same reference numerals.

  FIG. 2 schematically shows the entire apparatus of the cooling tower 1. This cooling tower 1 is constituted by a flow of taking outside air from the louvers 10a, 10b on both sides and discharging it from above, and a blower 8 is provided on the upper side. The entire apparatus is installed on the gantry 1a, 1b, and a water storage tank 11 is arranged on the lower side. The circulating water retained in the water storage tank 11 is sent to the heat exchanger 4 by the circulation pump 3 through the feed pipe 2. Subsequently, it is returned from the heat exchanger 4 to the cooling tower 1 via the return pipe 5 and sent to the upper watering tanks 12a and 12b arranged on both sides of the upper part of the apparatus.

  As shown in FIG. 3, water spray holes 13 having a diameter of about 9 to 10 mm are provided in the upper water tanks 12 a and 12 b so as to be scattered substantially evenly on the bottom surface. The upper water tanks 12a and 12b maintain a water depth of about 5 cm, and the circulating water is dropped into the fillers 14a and 14b (see FIG. 2) from the water holes 13 and falls into the water tank 3. During this time, the circulating water is cooled by coming into contact with outside air sucked by the rotation of the blower 8. In FIG. 3, the code | symbol 15 shows a water distribution box and 16 shows an outflow port.

  As the circulating water pipe (see FIG. 1), in addition to the above-described feed pipe 2 sent from the cooling tower 1 to the heat exchanger 4 and the return pipe 5 sent back from the heat exchanger 4 to the cooling tower 1, replenishment A water introduction pipe 7 and a blow water pipe 9 are provided. In addition, a continuous measurement monitoring device 17 for fungi and / or algae is disposed in the system from the circulation pump 3 to the heat exchanger 4. This device 17 is provided so as to perform measurement by automatically and continuously collecting sample water, filtering, extraction, refrigeration and centrifugation.

  As shown in FIG. 4, the upper watering layers 12a and 12b on both sides via the water distribution box 15 are homogeneously solid containing a photocatalyst that suppresses the generation of fungi and / or algae (hereinafter simply referred to as “solid”). .) P is loaded. Since the solid P uses the photoreactivity of titanium oxide as described later, it is preferable to install the solid P in the upper watering tanks 12a and 12b having the highest natural light receiving ability. However, it may be provided in any one of the cooling towers 1 having high water contact property, or may be irradiated by artificial ultraviolet irradiation. In FIG. 4, reference numeral 8 a denotes a belt cover that accommodates a driving belt for the blower 8, 8 b denotes a fan support, and 8 c denotes a fan cover.

  In the upper watering tank 12a (12b), as shown in FIG. 5, the solid material P is laid on the net-like substance 18 so as not to clog the watering holes 13, so that it is spread to a thickness of 1.5 cm to 2 cm. Yes. The solid material P has a function that allows the surface of the light source to be constantly updated by the flow of the circulating water, and the circulating water is always in contact with the solid material P and decomposed. Thereby, the chemical | medical agent injection | pouring to a circulation type cooling water system can be made unnecessary.

  The solid P will be described. A material in which titanium oxide is supported on crystalline quartz having high light transmittance and a plasticizer such as glass powder and clay mineral are kneaded and molded at a melting point of 600 ° C. or higher. Preferably, it is a solid obtained by firing in the region of 900 ° C. to 1200 ° C. or less.

  The material for supporting titanium oxide, which is a constituent material, is not particularly limited, but crystalline quartz is preferable because it is desirable that the material has high light transmission and can withstand firing. is there. Crystalline quartz having an average particle size of 15 μm or less has excellent plasticity and good moldability. Since the glass powder solidifies again when cooled after melting, the shape retention can be stably maintained as a solid. This solid material P is kneaded to form a homogeneous layer to the inside, and even if the surface is worn, its function is not lost.

The mechanism of decomposition of organic substances by titanium oxide will be described. Titanium oxide is a semiconductor material having a band gap of 3.0 to 3.2 eV, and electrons (e ⁻ ) And holes (h ⁺ ) are generated in the crystal.

Electrons (e ⁻ ) react with oxygen (O ₂ ) present on the catalyst surface to generate superoxide ions (O ²⁻ ). On the other hand, the hole (h ⁺ ) reacts with the OH group of water to generate a hydroxy radical (.OH). Such active oxygen radicals such as .OH attack the organic matter approaching or adsorbed on the surface of titanium oxide and oxidatively decompose. Based on such functions, it can be decomposed into carbon dioxide and water.

In Example 1, a cooling tower (manufactured by Kuken Kogyo Co., Ltd., model SKB-24TR, inlet temperature 40 ° C., outlet temperature 30 ° C., circulating water volume 0.4 m ³ / min) and a heat exchanger are connected by piping, A circulating cooling water treatment system was adopted. Held water volume of the cooling tower system, the tower aquarium held water 1.44 ^3, a pipe system possesses water of about 0.49 m ^3, were held set to a total of about 2m ^3.

  The solid material P used in Example 1 was prepared by kneading a material in which titanium oxide was supported on crystalline quartz having an average particle diameter of 7 μm, glass powder, and clay mineral as a plasticizer, and φ8 mm and length 10 mm by extrusion molding. It was fired after molding as a cylindrical solid. The obtained solid P: 2 kg was filled in a net-like container and provided at four locations (see FIG. 4) of the upper watering tank.

  It was confirmed that the form of titanium oxide in the solid P was a mixed phase of anatase and rutile.

  The replenishment water was regularly replenished to the cooling tower and operated continuously for 8 weeks (total operation for 56 days). Meanwhile, the drug was not administered to the circulating cooling water system, and circulating water was collected every other week, and chlorophyll a was quantified to determine the algae inhibitory effect and algicidal effect. Samples for quantification of chlorophyll a were each collected 2000 ml of circulating water, filtered through a glass filter, and extracted with acetone. This was centrifuged to obtain a measurement sample, and the absorbance of the obtained sample water was measured.

  As a result, as shown in FIG. 6, it was confirmed that the concentration of chlorophyll a decreased by 65% in 2 weeks, and the decrease rate exceeded 90% after 7 weeks.

In Example 2, a part is extracted from the circulating water system of the cooling tower (manufactured by Kuken Kogyo Co., Ltd., model SKC-40TR ₀ , inlet temperature 35 ° C., outlet temperature 20 ° C., circulating water volume 120 L / min), and is shown in FIG. As described above, the water was passed through the UV-catalyzed photocatalytic water purification device 19 and then returned to the circulating water system. The amount of water held in the cooling tower system was about 250 L in the tower water tank and about 30 L in the piping system, and was set to be about 280 L in total.

  As shown in FIG. 8, the UV lamp-provided photocatalyst water purification device 19 used in Example 2 includes an ultraviolet lamp 20, a quartz tube glass 21, a stainless steel net 22 filled with solids, a flow meter 23, a diffuser tube 24, and an air hose 25. It is configured with. Here, solid material: 3 kg is filled in the stainless steel net 22 and the inside of the packed bed is structured so that water can pass from the lower part, and the water flow rate inside the UV lamp-providing photocatalyst water purification device 19 is 12 L / Set to min.

  The UV lamp 20 used in the UV lamp-providing photocatalyst water purification device 19 was GL-30 manufactured by Tozai Denki Sangyo Co., Ltd., and was equipped with a lamp with a wavelength of 253.7 nm and a rated power of 30 W.

  The cooling tower was continuously operated for 28 days while supplying replenishing water regularly. In the meantime, no chemical was administered to the circulating cooling water system, and the UV lamp was repeatedly turned on and off every 4 hours. Circulating water was collected periodically and chlorophyll a was quantified to determine the algae inhibitory effect and algicidal effect. Samples for quantification of chlorophyll a were each collected 2000 ml of circulating water, filtered through a glass filter, and extracted with acetone. This was centrifuged to obtain a measurement sample, and the absorbance of the obtained sample water was measured.

  As a result, as shown in FIG. 9, the concentration of chlorophyll a decreased by about 60% in about 50 hours, and the decrease rate reached about 75% after 200 hours, and it was confirmed that the concentration was maintained almost constant thereafter. did.

  In addition to the installation method shown in FIG. 7, the present apparatus can be incorporated into the cooling tower apparatus.

  Further, in order to efficiently swing the solid matter P filled in the stainless steel net 22, air may be inserted from the air hose 25 when the water flow is insufficient.

  The embodiment described above shows a specific example, and the present invention is not limited to this embodiment.

It is explanatory drawing which shows the circulation system of the circulating cooling water which concerns on an example of this invention. It is explanatory drawing which shows the cooling tower of FIG. 1 schematically. It is explanatory drawing which shows roughly the upper watering tank of FIG. FIG. 2 is an overhead view schematically showing the cooling tower of FIG. 1. It is sectional drawing which shows the upper watering tank of FIG. 1 schematically. It is a graph which shows the reduction | decrease result of the chlorophyll a by the processing method of the circulating cooling water which concerns on Example 1 of this invention. It is explanatory drawing which shows the circulation system of the circulating type cooling water which concerns on another example of this invention. It is sectional drawing which shows roughly the UV lamp provision photocatalyst water purification apparatus of FIG. It is a graph which shows the reduction | decrease result of the chlorophyll a by the processing method of the circulating cooling water which concerns on Example 2 of this invention. It is explanatory drawing which shows the typical circulation system of the circulating cooling water which concerns on a general example.

Explanation of symbols

P Solid matter containing photocatalyst 1 Cooling tower 2 Feeding pipe 3 Circulating pump 4 Heat exchanger 5 Return pipe 7 Makeup water introduction pipe 8 Blower 9 Blow water pipe 10a, 10b Louver 11 Reservoir 12a, 12b Upper sprinkler 13 Sprinkling holes 14a, 14b Filler 15 Distribution box 16 Outlet 17 Continuous measurement monitoring device 18 Net substance 19 UV lamp-provided photocatalytic water purification device 20 UV lamp 21 Quartz tube glass 22 Stainless steel net (solid P filling)
23 Flow meter 24 Diffuser 25 Air hose

Claims (5)

  A water treatment method for suppressing the generation of fungi and / or algae in a circulating cooling water system, wherein a homogeneous photocatalyst having a function capable of constantly renewing the surface with respect to a light source by a flow of cooling water is provided. A treatment method for circulating cooling water, wherein the contained solid matter is disposed in a tower of a cooling tower, and the cooling water is brought into contact with the solid matter to decompose the organic matter.   2. The circulation system according to claim 1, wherein a solid material including a substance in which titanium oxide is supported on crystalline quartz is provided as a solid material having a function capable of constantly updating the surface of the light source. Cooling water treatment method.   As a solid having a function capable of constantly renewing the surface with respect to the light source, a material in which titanium oxide is supported on crystalline quartz, glass powder, and clay mineral of plasticizer are kneaded and molded, and the temperature is 600 ° C. or higher, preferably The method for treating circulating cooling water according to claim 1 or 2, wherein a solid material fired in a region of 900 to 1200 ° C or lower is provided.   The method for treating circulating cooling water according to any one of claims 1 to 3, wherein a light source containing ultraviolet rays such as sunlight is used to suppress generation of fungi and / or algae.   A device that continuously measures and monitors fungi and / or algae in water is installed in the cooling water circulation system so that sample water can be collected, filtered, extracted, refrigerated, and centrifuged automatically and continuously. The method for treating circulating cooling water according to any one of claims 1 to 4.

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