JPS6316994B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a closed loop cooling device.

In a closed-loop cooling system, for example, after a heat exchanger is cooled by cooling water sent by a water pump, this cooling water is guided to an air conditioning cooling tower, cooled, and then sent to the water pump again. According to
The water is configured to be sent to a heat exchanger.

In such a closed-loop cooling system, microorganisms adhere to and propagate on the walls of the heat exchanger, cooling water pipes, and air conditioning cooling tower during use, causing a decrease in heat exchange capacity and clogging problems.

To prevent these disorders, fungicides are used. As disinfectants, chlorine or chlorine-based agents, hydrogen peroxide, ozone, etc. are generally used. A closed-loop system has the disadvantage that when chlorine or chlorine-based chemicals are injected, chlorine ions that are injected together with these disinfectants or disinfectants accumulate and concentrate within the system, causing corrosion problems. On the other hand, since hydrogen peroxide decomposes into oxygen and water, it is preferable as a disinfectant for use in closed-loop systems. , which poses operational and economical problems. In order to eliminate these drawbacks, the ozone injection method, which has greater bactericidal power than these disinfectants, has a faster decomposition rate, and leaves nothing but oxygen after decomposition, is used as a closed-loop adhesion removal method. ing.

FIG. 1 is a system diagram showing a conventional closed-loop cooling system. In the figure, 1 is a closed-loop cooling water pipe, 2 is a water tank connected to this cooling water pipe, and 3 is a water tank connected to the water tank. 4 is a water pump that sends this cooling water to the cooling water pipe 1;
5 is a heat exchanger provided in the cooling water pipe 1; 6 is an air conditioning cooling tower having water sprinkling holes 7 connected to the cooling water pipe 1 on the outlet side of the heat exchanger; 8 is provided at the bottom of the water sprinkling hole 7; 9 is a blower that blows air to the lower part of this packed bed, 10 is a blower that sends air to the ozone generator 12 via the dryer 11, and 13 is a blower that sends ozonized air from the ozone generator 12 to the gas mixer 14. 15 is a gas mixing pump that sends water to the gas mixer 14; 16 is a gas mixer 14;
This is an ozonated water injection pipe that guides ozonated water from the cooling water pipe 1 to the cooling water pipe 1.

In the closed loop cooling system configured as described above, the cooling water 3 in the water storage tank 2 is sent to the cooling water pipe 1 by the water pump 4, and after cooling the heat exchanger 5, it is transferred to the air conditioning cooling tower. Water is sprayed from the water sprinkling holes 7 of 6 and flows down the packed bed 8 filled with filler. At this time, the cooling water flowing down comes into contact with the air blown by the blower 9, and a part of the cooling water evaporates into the blown air, thereby being cooled and stored in the water storage tank 2. The cooling water 3 in the water storage tank 2 is again sent to the cooling water pipe 1 by the water pump 4, forming a closed loop.

At this time, ozone generated by silent discharge is continuously or intermittently injected into the cooling water pipe 1. Ozone used for this purpose is produced by air pressurized by a blower 10, dried in an air dryer 11 until the dew point becomes -40°C or less, and sent to an ozone generator 12, where a silent discharge occurs. This converts some of the oxygen in the air into ozone, resulting in air containing highly concentrated ozone. This highly concentrated ozone-containing air is sent to the gas mixer 14 (water ejector in this conventional example) through the ozone air pipe 13, and is injected as microbubbles into the water sent from the gas mixing pump 15, where it is dissolved. . This ozonated water containing microbubbles is injected into the cooling water pipe 1 through the ozonated water injection pipe 16, and can kill microorganisms adhering to the wall surface of the cooling water pipe 1 to prevent trouble. At this time, ozone has an effective residual ozone concentration of
It is continuously injected to a level of about 0.1ppm, or
Alternatively, high-concentration ozone is injected over a relatively long period, ie, once a day for 5 minutes at an effective residual ozone concentration of 5 to 10 ppm.

However, in such a configuration, when gas and liquid come into direct contact in the air conditioning cooling tower, most of the ozone dissolved in the cooling water is dissipated into the atmosphere because ozone is a poorly soluble substance, and ozone There was a problem that it caused pollution. In order to eliminate such ozone dissipation into the atmosphere, it is possible to use a disinfectant that is highly soluble in water, such as hypochlorite ion, but as explained above, in a closed loop system, disinfectants ( The drawback is that hypochlorite ions), chlorine ions, etc. accumulate and concentrate in the system, causing corrosion problems.

The present invention was made to solve the above-mentioned drawbacks of the conventional ones, and by providing a device for injecting ozone into circulating cooling water containing bromide ions, ozone does not diffuse into the atmosphere and has strong sterilizing power. An object of the present invention is to provide a closed-loop cooling device that has the following features and can thereby prevent biofouling damage.

Ozone slowly reacts with bromine ions in water,
The reaction product does not dissipate into the atmosphere and has strong sterilizing power, and furthermore, when the reaction product decomposes, it returns to bromide ions, so the bromide ion concentration in the circulating cooling water does not increase. The present invention was made with attention to this point, and instead of continuously injecting bromine ions, the circulating cooling water is pre-impregnated with bromine ions, and a reaction is generated by the reaction between ozone and bromide ions. Since the product removes the adhesion of microorganisms, there is no release of disinfectant into the atmosphere, and there is no accumulation or concentration of corrosive substances in the circulating cooling water.
Biofouling can be removed from the entire closed loop system, including the air conditioning cooling tower.

FIG. 2 is a system diagram showing a closed loop cooling device according to an embodiment of the present invention. In the figures, 1 to 16 indicate the same or corresponding parts as in Figure 1,
The closed loop system and the microorganism removal device that generates ozone are constructed in the same manner as shown in FIG. 17 is a storage tank for storing bromide ions, and 18 is a supply pump for injecting bromide ions from this storage tank into the cooling water pipe 1.

In the cooling device configured as above,
Before injecting ozone, bromine ions are injected from the storage tank 17 into the cooling water pipe 1 by the supply pump 18, so that the bromine ion concentration in the circulating cooling water is several ppm.
When this happens, the supply pump 18 is stopped to stop the supply of bromide ions. Next, the ozone generator 12 is operated to generate air containing highly concentrated ozone. This highly concentrated ozone-containing air is sent to a gas mixer 14 (water ejector in this embodiment) through an ozone air pipe 13, and is formed as microbubbles in water containing bromide ions sent from a gas mixing pump 15. Injected and dissolved. At this time, ozone and bromine ions react, producing hypobromite ions that kill living organisms and remove biofouling problems.

According to the results of a three-month experiment conducted to demonstrate the effects of the present invention, bromine ions were injected in advance to bring the bromine ion concentration to approximately 4 ppm in the circulating cooling water, and bromine ions were injected midway through the experiment period. without any
When ozone was continuously injected at a concentration of 0.1 ppm relative to the amount of circulating cooling water, about 1 ppm of hypobromite ions were detected in the cooling water at the outlet of the air conditioning cooling tower 6 and in the circulating cooling water by iodometry. Also, apply ozone once a day for 5 to 5 minutes each time.
When injected intermittently at a concentration of 10 ppm, about 1 ppm of hypobromite ion was detected as above.
After completing this experiment, we investigated the adhesion situation and found that no adhesion was observed in the entire closed loop system including the air conditioning cooling tower 6. At this time, the cooling water at the outlet of the air conditioning cooling tower 6 was aerated with air, and the ozone concentration remaining in the cooling water was measured, but no ozone was detected.

Figure 3 is a curve diagram comparing the emission rate of generated hypobromite ions, hypochlorite ions, and ozone into the gas phase at pH 7.5. From Figure 3,
It can be seen that hypobromite ions, like hypochlorite ions, emit extremely little into the gas phase.

FIG. 4 is a curve diagram showing the lifetime of the generated hypobromite ions. From FIG. 4, it can be seen that once generated, the hypobromite ions are relatively stable and have a lifetime of several days. Figure 5 is a curve diagram comparing the sterilizing power of generated hypobromite ions, hypochlorite ions, and ozone against general bacteria.
The figure shows that although hypobromite ions are inferior in sterilizing power to ozone, they have a strong sterilizing power equal to or greater than that of hypochlorite ions. The present invention eliminates the adhesion and propagation of microorganisms using hypobromite ions that do not emit into the atmosphere and have strong sterilizing power.

In addition, in the above example, a case was explained in which dry air was used to generate ozone.
Oxygen may be used instead of dry air. Furthermore, since ozone can be injected in relatively long cycles, the ozone generator may be configured to store ozone generated by silent discharge in low-temperature silica gel or carbon tetrachloride, and use the stored ozone. , the same effect as the above embodiment is achieved. Further, the configuration of the closed loop cooling device is not limited to that shown in the drawings.

As described above, according to the present invention, circulating cooling water is impregnated with bromide ions and ozone is injected in advance, and hypobromite ions are generated by the reaction between bromide ions and ozone, so that sterilization is possible. The effect is that there is no release of chemicals into the atmosphere, no accumulation and concentration of corrosive substances in the circulating cooling water, and the ability to eliminate problems caused by microbial growth and adhesion in the entire closed loop system, including the air conditioning cooling tower. There is.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing a conventional closed-loop cooling system, Fig. 2 is a system diagram showing a closed-loop cooling system according to an embodiment of the present invention, and Fig. 3 is a system diagram showing the flow of hypobromite ions into the atmosphere. FIG. 4 is a curve diagram showing the emission rate, FIG. 4 is a curve diagram showing the lifespan of hypobromite ions, and FIG. 5 is a curve diagram showing a comparison of the bactericidal powers of various disinfectants. In each figure, the same reference numerals indicate the same or equivalent parts, 1 is a cooling water pipe, 2 is a water storage tank, 4 is a water pump, 5 is a heat exchanger, 6 is an air conditioning cooling tower, 7 is a water sprinkling hole, and 8 is a Filled bed, 11 is a dryer, 12 is an ozone generator, 14 is a gas mixer, 17 is a storage tank, 18
is the supply pump.

Claims (1)

[Scope of Claims] 1. A closed loop cooling device equipped with a heat exchanger cooled by circulating cooling water, characterized in that it is equipped with a device for injecting ozone into the circulating cooling water containing bromide ions. System cooling device. 2. The closed loop cooling device according to claim 1, further comprising a device for injecting bromine ions into the circulating cooling water. 3. The closed loop cooling device according to claim 1 or 2, characterized in that ozone is injected continuously or intermittently.