JPH07127992A - Method for removing microbe in heat exchanger - Google Patents

Abstract

PURPOSE:To promote the generation of active oxygen and further to perform a superior disinfection even with a small amount of ozone by a method wherein ozone gas may easily be decomposed into active oxygen. CONSTITUTION:A method for disinfecting of a condenser 2 for feeding ozone gas so as to disinfect microbe grown in the condenser 2 for heat exchanging with cooling water is carried out such that moisture saturated air of which humidity is adjusted with a drain trap 19 within the condenser 2 is mixed with ozone gas after discharging cooling water from the condenser 2 and then the mixed gas is fed. Then, ozone gas is rapidly decomposed into active oxygen with moisture contained in the saturated water steam included in the moisture saturated air. Accordingly, a large amount of active oxygen are generated even with a small amount of ozone gas and a powerful disinfecting action can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing microorganisms in a heat exchanger using ozone gas.

[0002]

2. Description of the Related Art Conventionally, in a thermal power plant or the like, there is a condenser which is a kind of heat exchanger for cooling steam used for power generation. Then, for cooling this type of condenser, normal seawater is used to continuously circulate in the condenser.
However, seawater contains a large amount of microorganisms and the like, and if these microorganisms propagate, they cause inconveniences such as clogging of minute heat transfer tubes in the condenser and deterioration of the heat exchanger. Therefore, there is an ozone treatment method for removing microorganisms by using ozone gas having a bactericidal action for the purpose of avoiding the reproduction of microorganisms and the like.

For example, a method disclosed in Japanese Patent Publication No. 59-34279 is known as an ozone treatment method of this type. That is, all the seawater in the condenser is drained, and then ozone gas is injected into the condenser to remove microorganisms and the like with ozone gas.

[0004]

However, since microorganisms and the like are not sterilized by ozone gas itself, they are sterilized by activated oxygen generated immediately after being decomposed by being contacted with water contained in the air or the like. Depending on the dry condition after cooling water is drained from the condenser, ozone gas is less likely to be decomposed into activated oxygen. Therefore, there is a problem that the amount of activated oxygen generated in the condenser is reduced and the bactericidal action of microorganisms is reduced.

The present invention has been made by paying attention to the problems existing in such a conventional technique, and the purpose thereof is to make ozone gas into active oxygen easily and Another object of the present invention is to provide a method for removing microorganisms in a heat exchanger capable of obtaining various sterilizing effects.

[0006]

In order to solve the above problems, the present invention is a heat exchanger for exchanging heat exhausted from equipment with cooling water, and sterilizes microorganisms propagated in the heat exchanger. In order to sterilize the heat exchanger by injecting ozone gas, the cooling water is discharged from the heat exchanger, and the saturated water and ozone gas are mixed and injected into the heat exchanger. .

[0007]

In the present invention thus constructed, the cooling water is discharged from the heat exchanger, and then the water saturated with air and ozone gas are mixed and injected. Then, the ozone gas comes into contact with saturated water vapor contained in the water saturated air and is rapidly decomposed into activated oxygen. Therefore, a large amount of activated oxygen is generated even with a small amount of ozone gas, and a strong bactericidal action is obtained.

[0008]

【Example】

(First Embodiment) A first embodiment in which the present invention is embodied in a cooling unit for a thermal power plant will be described below with reference to the drawings.

As shown in FIG. 1, a thermal power plant cooling unit 1 is installed on a steam discharge path in order to cool and reuse high temperature steam discharged from a generator during thermal power generation. . This cooling unit 1 is equipped with a condenser 2 as a heat exchanger. In the condenser 2, a seawater supply pipe 3 connected to a seawater supply port (not shown),
Seawater discharge pipe 4 connected to a seawater discharge port (not shown)
It is connected to the.

A partition valve 5 for adjusting the amount of seawater supplied is provided on the seawater supply pipe 3. A partition valve 6 for adjusting the discharge amount of seawater is provided on the seawater discharge pipe 4. Therefore, the cooling seawater taken in from the supply port is discharged from the discharge port through the seawater supply pipe 3, the condenser 2 and the seawater discharge pipe 4. Then, during the cooling of the steam, heat exchange is performed between the seawater supplied to the condenser 2 and the high-temperature steam,
As a result, the water vapor is cooled to a predetermined temperature. A drain pipe 22 having a drain valve 21 for drainage is connected to the condenser 2. A pipe 7 for inputting ozone gas, which is provided with a valve 23, is connected to one side of the condenser 2, and a compressor 8 is connected to the tip thereof.

An air introducing pipe 25 having a valve 24 is connected between the condenser 2 on the pipe 7 and the valve 23. An air volume adjusting valve 9 capable of adjusting the amount of air blown from the compressor 8 is interposed on the pipe 7. An ozonizer 10 for generating ozone is connected to the pipe 7 via an ozone supply pipe 11 having an ozone injection adjusting valve 12. In addition, on the pipe 7, the humidifier 1
3 are connected via a humidity supply pipe 14 equipped with a humidification adjusting valve 15.

A drain trap 19 is interposed on the pipe 7 between the ozone supply pipe 11 and the connection point with the humidification adjusting valve 15. Drain trap 1
At 9, the air mixed with the moisture is adjusted from the humidifier 13 to the moisture saturated air, and the excess moisture of the moisture is discharged to the exhaust pipe 20.
Is discharged through.

At the outlet of the condenser 2, a waste ozone treatment tower 18 is provided.
Is connected via an exhaust pipe 16 equipped with a valve 17. The unreacted ozone gas after ozone treatment is decomposed in the exhaust ozone treatment tower 18 to eliminate its toxicity and then released to the atmosphere.

Next, a method for removing the microorganisms propagated in the condenser 2 by ozone gas will be described. When performing the ozone treatment, the partition valves 5 and 6 are closed, the drain valve 21 and the air introduction valve 24 are opened, and the seawater in the condenser 2 is discharged to the outside. After that, the drain valve 21 and the air introduction valve 24 are closed, and the condenser 2
Cut off the connection between the inner area and the outer area.

Then, the air flow rate adjusting valve 9, the ozone injection adjusting valve 12, the humidification adjusting valve 15 and the valve 17 are simultaneously opened. Then, the pipe 7, the inside of the condenser 2 and the exhaust pipe 16 are communicated with each other. When the compressor 8 is operated, the compressed air from the compressor 8 is transferred to the humidifier 13
It is pumped to the drain trap 19 through the pipe 7 together with the moisture from the. The moisture is adjusted to a predetermined value in the drain trap 19, and the excess moisture is removed, so that only the moisture-saturated air is discharged. The discharged water-saturated air is mixed with ozone gas generated by the ozonizer 10, and the air-fuel mixture is pumped into the condenser 2.

The ozone gas injected into the condenser 2 comes into contact with the saturated steam contained in the water saturated air and is efficiently and promptly decomposed into activated oxygen. The activated oxygen and the microorganisms in the condenser 2 come into contact with each other to be sterilized. At this time, since the moisture-saturated air and the ozone gas are mixed immediately before being injected into the condenser 2, they are not decomposed into activated oxygen in the pipe 7 and are activated immediately after being injected into the condenser 2. Decomposed into oxygenated oxygen.

Further, during sterilization, saturated water vapor contained in the mixture of water saturated with air and ozone gas does not form a water film on the inner surface of the condenser 2, so activated oxygen decomposed from ozone gas is disturbed by the water film. Without touching the inner surface of the condenser. That is, the activated oxygen is uniformly contacted with the microorganisms without being biased, and the sterilizing power thereof is made uniform. After the sterilization process, the exhaust ozone is introduced into the exhaust ozone processing tower 18 through the exhaust pipe 16, is decomposed into oxygen from the exhaust ozone processing tower 18, and is discharged into the atmosphere.

Therefore, by mixing ozone gas and moisture-saturated air, ozone gas is rapidly decomposed into activated oxygen in a short time, and a large amount of activated oxygen is generated even with a small amount of ozone gas, which has a strong bactericidal action. Obtainable. Therefore, the sterilization ability can be improved, and the ozonizer can be downsized. That is, it is possible to reduce the manufacturing costs of the cooling unit 1 and the running costs such as equipment costs and operating costs.

Further, by mixing the ozone gas with the moisture-saturated air whose humidity is adjusted by the drain trap 19,
It is possible to prevent the formation of a water film covering the surface of the microorganisms attached to the condenser 2 during the sterilization. In other words, this water film does not hinder the contact of activated oxygen with microorganisms, so that the inside of the condenser 2 can be sterilized uniformly.

Furthermore, since ozone gas is rapidly decomposed into activated oxygen in a short time, the sterilization time can be shortened. As a result, the stop time of seawater circulation (circulating cooling water) during sterilization can be greatly shortened.

The present invention is not limited to the above embodiment, and may be appropriately modified as follows without departing from the spirit of the present invention. (1) For example, each valve 15, 17, 21, 23, 24
May be replaced by any type of solenoid valve or manual valve.

(2) A blower may be used instead of the compressor 8. (3) The exhausted ozone after the sterilization treatment may be returned to the input system such as the pipe 7 and reused.

[0023]

As described in detail above, according to the present invention, by facilitating the decomposition of ozone gas into activated oxygen, a strong bactericidal action can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a cooling unit in the present embodiment.

[Explanation of symbols]

 2… Condenser (heat exchanger)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Kawauchi, Inayama City, Aichi Prefecture, 1st small needle, Energy Support Co., Ltd. (72) Inventor, Norinori Matsuda, Inayama City, Aichi Prefecture, 1st upper character needle, Energy Support Company

Claims (1)

[Claims] 1. A method for removing microorganisms in a heat exchanger for exchanging exhaust heat of equipment with cooling water, wherein ozone gas is injected to sterilize microorganisms propagated in the heat exchanger. A method for removing microorganisms in a heat exchanger, characterized in that cooling water is discharged from the heat exchanger, and water saturated with air and ozone gas are mixed and injected into the heat exchanger.