JPS592559B2 - Microorganism removal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a device for removing blockages caused by microorganisms that breed in water pipes, such as cooling water pipes in power plants.

Conventionally, there has been a device of this type as shown in FIG.

In the figure, reference numeral 1 denotes a cooling water pipe, and the seawater, river water, etc. sucked in by a water pump 2 are sent to a water pipe 3, cooled a heat exchanger 4, and then drained from a return pipe 5. .

Reference numeral 6 denotes a microorganism removal device, which prevents microorganisms from adhering and propagating on the walls of the water supply pipe 3, water return pipe 5, and heat exchanger 4 while the cooling water pipe 1 is in use, thereby reducing the water supply amount. be.

This microorganism removal device 6 is capable of quantitatively dissolving chemicals such as chlorine-based oxidizing agents such as sulfur-IJium hypochlorite and chlorine water in which chlorine gas is dissolved in water stored in a chemical storage tank 7. A predetermined amount of the chemical is mixed into the cooling water of the water pipe 3 via the chemical injection pipe 9 by the pump 8 .

Due to the bactericidal and algicidal effects of the mixed chlorine or chlorine-based chemicals, adhesion and propagation of microorganisms on the wall surface of the cooling water pipe 1 is prevented.

The amount of chlorine mixed into the microorganism removal device 6 is adjusted so that the effective residual chlorine concentration in the water is about 0.5 ppm.

In order to maintain the effective residual chlorine concentration at 0.5 ppm, it is necessary to inject an excess amount of chlorine that is consumed by reacting with pollutants in the water, and this value varies depending on the degree of contamination of the water.
Generally, it is necessary to implant 1 ppm or more.

According to such a microorganism removal device using chlorine-based chemicals, it is necessary to constantly mix 1 ppm or more of chlorine into the cooling water, which increases the amount of chlorine used and increases operating costs.

Furthermore, chlorine and its compounds discharged into seawater and river water may generate organic pollutants and toxic compounds in the water, potentially contaminating public water supplies, and wastewater treatment facilities must be installed to prevent this. However, it also had drawbacks such as requiring a huge amount of cost.

In order to eliminate the drawbacks of conventional devices as mentioned above, we need to use chlorine-based chemicals instead, which have stronger bactericidal and algicidal effects than the above chemicals, have a faster self-decomposition time, and do not leave anything other than oxygen after decomposition. A device has been proposed that uses ozone to prevent clogging of cooling water pipes caused by microorganisms without the risk of causing pollution.

To prevent the adhesion and propagation of microorganisms on the walls of cooling water pipes using ozone, the effective residual ozone concentration is 0. It is known that this objective can be achieved by continuously injecting ozone at a concentration of about 1 ppm.

However, in order to maintain this effective residual ozone concentration at O, ], ppm, it is necessary to replenish the amount consumed by the oxidation reaction between ozone and pollutants contained in the water, and the injected ozone is less than the effective residual ozone. Reaching several times the concentration, 0.5pp
It requires about 100 m.

Therefore, although using ozone to prevent the adhesion and propagation of microorganisms on the pipe walls has the advantage of not causing pollution, it is not economical considering that the price of ozone is about four times that of chlorine-based chemicals. However, it is not widely used in reality due to problems.

By the way, if the effective residual ozone concentration is 0. In order to prevent microbial damage due to the mixing of lppm of ozone into water pipes, ozone must be continuously injected.

However, by generating highly concentrated ozone and mixing this ozone into water pipes, it is possible to completely kill and remove microorganisms on the walls of water pipes, and it takes a considerable amount of time before microorganisms reproduce and blockage problems appear. It takes time.

Focusing on this, it is conceivable that by periodically injecting high-concentration ozone, microbial damage to cooling water pipes can be prevented, thereby significantly reducing the total amount of ozone used.

According to experiments, 5-10 ppm once a day for 5 minutes
It has been shown that microbial damage can be removed by injecting ozonated water with a concentration of .

This condition varies depending on the type and amount of microorganisms, the temperature of the water used, and the composition and amount of organic pollutants. Generally, it is necessary to apply several pp.
It is sufficient to inject ozone water with a concentration of about 100 ppm to several tens of ppm.

This method of periodically injecting high-concentration ozone is superior to the method of continuously injecting low-concentration ozone.

The amount of ozone used can be reduced to a certain extent.

Although it is possible to reduce the total amount of chlorine used by periodically injecting high-concentration chlorine, the bactericidal and algicidal effects are not so great even if the chlorine concentration is increased; Even if the total amount is reduced if periodically released into public waters, pollution will not be prevented.

Figure 2 shows the above-mentioned microorganism removal device using high-concentration ozone. The water is sent to cool the heat exchanger 4 and drained from the return pipe 5.

6 is a microorganism removal device that prevents the adhesion and propagation of microorganisms by injecting ozone generated by silent discharge into the cooling water pipe 1 during water supply. It is dried in a container 11 until the dew point becomes 140 degrees Celsius or less and sent to an ozone generator 12, where a portion of the oxygen in the air is converted into ozone by silent discharge and becomes highly concentrated ozone. Contains air.

This highly concentrated ozone-containing air is sent to a gas mixer 14 (water ejector in this embodiment) via an ozone air pipe 13, and is injected into water sent from a gas mixing pump 15 as fine bubbles.

This highly concentrated ozonated water containing microbubbles is supplied to the ozonated water injection pipe 1.
6 and is injected into the water supply pipe 3 of the cooling water pipe 1 to completely kill microorganisms adhering to the wall surface of the cooling water pipe 1 and prevent trouble.

At this time, since the injection of highly concentrated ozone water is performed periodically, the operation of the microorganism removal device 6 is suspended until the next injection.

According to the microorganism removal device that periodically injects high-concentration ozone as described above, the amount of ozone used can be significantly reduced compared to the conventional device that continuously injects low-concentration ozone. The usage cost can be lower than that of

However, on the other hand, the above-mentioned equipment is operated only for a short time to generate high concentration ozone, and is stopped most of the time, so the operating rate is low, and it is necessary to generate high concentration ozone in a short time. The disadvantage was that the equipment construction costs were high.

This invention was made to eliminate the above-mentioned drawbacks.
Ozone is generated over a long period of time before the ozone injection point, and this ozone is adsorbed and stored in an adsorbent such as silica gel that is kept at a low temperature.The ozone is extracted at predetermined intervals by vacuum suction. The purpose is to provide a large-scale facility with a high operating rate.

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 3, 1 is the same cooling water pipe as in the conventional device;
is a microorganism removal device.

In this microorganism removal device 6, raw oxygen in an oxygen storage tank 17 is sent to an ozone generator 12 by a blower 18 for oxygen circulation.

Within this ozone generator 12, a portion of the oxygen is converted into ozone by silent discharge and becomes ozone-containing oxygen.

After this ozone-containing oxygen is cooled by a heat exchanger 19, it enters an ozone adsorption/desorption device 20, where only ozone is adsorbed and stored.

Note that the remaining oxygen undergoes heat exchange in the heat exchanger 19 (for example, becomes room temperature), returns to the oxygen storage tank 17, and is used as raw material oxygen.

FIG. 4 shows in detail the ozone adsorption/desorption device 20 in which ozone is adsorbed and stored, and for example, two adsorption/desorption groups 2L22 are provided inside.

In one of the adsorption/desorption groups 21 currently in the process of adsorbing ozone, ozone-containing oxygen sent from the inflow pipe 23 enters the white group of the adsorption/desorption group 21 through the electric valve 24 .

Ozone-containing oxygen comes into contact with the silica gel filled in this inner cylinder, and only ozone is adsorbed by the silica gel.

Note that the amount of ozone adsorbed by silica gel increases as the temperature of silica gel decreases.

Therefore, low-temperature brine cooled by the refrigerator 25 is circulated through the outer cylinder portion of the adsorption/desorption group 21 to cool the silica gel.

The cooling temperature of the brine is practically 1408C or higher considering the economic efficiency of the cooling equipment such as the refrigerator 25, the brine circulation pump 26, the brine flow pipe 28, the electric valves 29 and 30, and the cooling water pump 27. It is used at about -60°C.

When the silica gel in the adsorption/desorption group 21 is saturated with ozone,
The ozone adsorption process is switched to the other adsorption/desorption group 22, and ozone is stored by the same operation as above.

When the silica gel in the two adsorption/desorption groups 21.22 is saturated, the ozone generator 12 stops its operation, and all electric valves 24, 3L32 and 33.34.35
closes and waits for the ozone desorption process.

By the way, desorption (separation) of ozone from silica gel is easier at higher temperatures, so the operation of the cooling device is stopped before the ozone is injected into the water pipe 1, and the silica gel is desorbed when ozone is desorbed. The temperature is raised and recovered to a predetermined temperature.

Therefore, the adsorption/desorption group 2
．． By controlling the operation of the ozone generator 12 (i.e., controlling the amount of ozone generated at the start of operation or during operation) so that the ozone is saturated or completely adsorbed into the silica gel in the ozone generator 12, the connection between the ozone generator 12 and the cooling device is improved. Since the operations can be synchronized, the operation control becomes easier, and the time required to operate the cooling device is not unnecessarily lengthened, but the operating cost becomes economical.

Thereafter, when the period for injecting ozone into the cooling water pipe 1 is reached, the electric valve 31.34 of the adsorption/desorption group 21.22 is opened, and the stored ozone is driven by the ejector pump 36 shown in FIG. However, due to the ejection effect of the water ejector 37, the ozone in the adsorption/desorption groups 21 and 22 is sucked under reduced pressure through the air pipe 13.

The sucked ozone is injected as microbubbles into the water sent from the ejector pump 36, dissolved into ozone water, and sent from the ozone water injection pipe 16 to the water pipe 3 of the cooling water pipe 1.

The water ejector 37 has the function of sucking the ozone adsorbed by the adsorption/desorption groups 21.22 under reduced pressure (ozone becomes difficult to decompose in a low pressure state) and the function of dissolving ozone in water.

Note that during ozone desorption, the temperature of the silica gel increases as described above, and ozone is easily desorbed.

The number of adsorption/desorption groups in the ozone adsorption/desorption device can be determined economically based on the ozone storage capacity of the adsorption/desorption groups, ozone injection period, ozone concentration, injection amount, ozone generator operating time, etc. Well, it is not limited to two.

Furthermore, in the above embodiment, a case was explained in which microorganisms adhering and propagating on the walls of cooling water pipes are removed. The same effects as in the embodiment are achieved.

As described above, according to the present invention, the ozone in the adsorption/desorption device, which stores ozone over a long period of time and releases it in a short period of time, is periodically and intermittently desorbed in a short period of time by vacuum suction, resulting in a high concentration of ozone in the water. Since we are equipped with an ozone mixing device that mixes ozone, high-concentration ozone that is temporarily used in large quantities can be generated in advance using a small ozone generator and stored in the adsorption/desorption device, making it possible to save time on equipment. This method has the effect of being able to be made smaller and improving the operating rate of the device, and furthermore, the amount of ozone used can be significantly reduced compared to the conventional method in which ozone is continuously injected, making it suitable for practical use.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing a water pipe microorganism removal device using chlorine-based chemicals, Fig. 2 is an explanatory diagram showing a water pipe microorganism removal device using ozone, and Fig. 3 is an embodiment of the present invention. FIG. 4 is an explanatory diagram showing the ozone adsorption/desorption device according to the present invention. In the figure, 1 is a cooling water pipe, 6 is a microorganism removal device, 1
2 is an ozone generator, 20 is an ozone adsorption/desorption device, 21, 2
2 is an adsorption/desorption group, and 37 is a water ejector. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A microorganism removal device that uses ozone to remove microorganisms that propagate on water pipe walls, comprising: an ozone generator that generates ozone; and a storage of the ozone generated by the ozone generator over a long period of time. and an ozone mixing device that periodically desorbs ozone stored in the adsorption/desorption device in a short period of time by vacuum suction and mixes highly concentrated ozone into water. Microorganism removal device. 2. The microorganism removal device according to claim 1, wherein the ozone mixing device is a water ejector.