JPH1123189A - Cooling capilary tube cleaning apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a discharge accident of a sponge ball used to clean a condenser in a power plant. SOLUTION: A capillary tube of a condenser in a power plant is cleaned by a method having the steps of distributing and passing many sponge balls in and through many capillary tubes together with cooling water, capturing only the balls, discharging the water into a sea area, and again passing the captured balls through the tubes, thereby removing slime on the inner surface of the tube. The ball is made of biodegradable resin, and used by sterilizing it by an ultraviolet ray 22 from an emitting unit during circulating using. Thus, its cleaning effect is not lowered, and even if the balls are partly discharged into the sea area, it is decomposed by microorganism to eliminate the discharging accident.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for cleaning thin tubes for cooling, and more particularly to an apparatus for cleaning thin tubes using a sponge ball made of a biodegradable plastic. The present invention relates to a cooling thin tube cleaning apparatus using the sponge ball, which is applied to a water heater or a heat exchanger of a seaside complex.

[0002]

2. Description of the Related Art As is well known, a condenser for a thermal or nuclear power plant cools steam after work in a turbine with seawater or the like.
It is a device that condenses, creates a vacuum and collects it as condensate.

[0003] By the way, in this thermal and nuclear power plant,
A surface condenser capable of obtaining a low turbine exhaust pressure and recovering condensate as boiler water is employed.

The structure is composed of a number of cooling thin tubes horizontally mounted between tube plates at both ends of the body, a cooling water chamber and a condensate reservoir surrounding the tube plates.

[0005] The cooling water chamber is rubber-lined with mild steel, and the condenser upper body, which is a turbine exhaust passage, is connected to a steam turbine and a rubber expansion joint.

[0006] The cooling capillary is usually 25.4 mmφ,
A cooling seawater flow velocity of less than 2 m / s is designed with a thickness of 0.5 to 1.2 mm. For example, a thermal power plant with an output of 600 MW has about 20,000 cooling tubes.

[0007] Such a cooling tube includes aluminum brass (copper containing 22% of zinc, 2% of aluminum, and 0.1% of arsenic).
An alloy added so as to have a concentration of 0.4%) is used in the tube sheet in many cases, and Nebul brass is used in each of the tube sheets.

Recently, all titanium condensers have begun to be employed because of their advantages in terms of anticorrosion measures. In this case, the titanium tube is attached to the titanium tube sheet by welding.

Factors that reduce the performance of the condenser include a rise in the temperature of seawater and dirt on the inner surface of the cooling tubule (biological dirt). In particular, the removal of biological dirt is called biological film removal. I have.

A typical sponge ball type cleaning for removing a biofilm and a slime during operation in a thermal power plant or the like is a sponge ball type cleaning. There are hits.

Among them, as one of the measures for removing the biological film and the slime adhered to the inner surface of the cooling tube of the condenser,
The sponge ball type washing requires a pressure difference of 0.2 kg / cm ² or more at the inlet and outlet of the cooling tubing, but has a feature that continuous washing can be performed during the operation of the condenser.

That is, this sponge ball type cleaning is
A sponge ball is introduced into the cooling thin tube together with the cooling water to remove the biological film and slime on the inner surface of the thin tube by circulating the sponge ball. The sponge ball is constituted by a ball circulation path, a ball catching device, and the like. The sponge ball is made of natural rubber or synthetic rubber open-cell sponge rubber, its diameter is 1 to 3 mm larger than the inner diameter of the thin tube, and its specific gravity is almost the same as water, and it is evenly distributed in water. (For example, JP-A-58-210500, JP-A-59-24197, JP-A-60-295,
JP-A-60-69497, JP-A-60-8969
No. 5, etc.).

Such a sponge ball type cleaning apparatus will be further described based on the above-mentioned Japanese Patent Application Laid-Open No. 60-69497.

In FIG. 2, reference numeral 1 denotes a condenser for a power plant, in which a number of cooling tubes 2, 2...

Are supported by an inlet-side tube sheet 2A and an outlet-side tube sheet 2B. The inlet-side tube sheet 2A constitutes a part of the inlet-side cooling water chamber 3, and the outlet-side tube sheet 2A. 2B constitutes a part of the outlet side cooling water chamber 5.

Cooling water from an intake port (not shown) such as seawater is introduced into these inlet side cooling water chambers 3 as shown by arrows, and cooling water from the outlet side cooling water chamber 5 is shown by arrows. Is released into the sea.

Here, the inlet-side cooling water chamber 3 has:
A ball supply nozzle 4 that opens in the opposite direction to the flow of the cooling water is provided, and a funnel-shaped or inclined plate-shaped ball trapping strainer (ball trapping device) is provided in the outlet-side cooling water chamber 5. ) 6 are provided.

The ball supply nozzle 4 and the ball catching strainer 6 are connected to a ball return conduit (ball circulation path) 7.
The ball return conduit 7 has a ball monitor 8 and a ball supply / extraction tank 9 (ball storage device).
And a ball circulation pump 16.

The ball monitor 8 is controlled by a ball momentum measuring device 11 provided in the ball return conduit 7.
The impulse, which is the product of the mass and speed of the sponge ball 10, is measured, and the wear of the sponge ball 10 is detected by the storage device 12, the comparison device 13, and the display device 14.
Reference numeral 15 denotes an adjuster.

Therefore, a large number of small sponge bottles
The ball 10 is supplied from a ball supply nozzle 4 by a ball circulation pump 16, is distributed to a large number of cooling thin tubes 2 along with the inlet side cooling water, and passes therethrough. The water is collected and collected by the water collecting strainer 6 and continuously circulates again.

As one of the operations of the sponge ball type washing apparatus, the number of the sponge balls 10 is set to about 10 to 15% of the number of the cooling thin tubes 2, and the cooling thin tubes 2 are changed every 5 minutes. I let it pass.

In general, it is desirable to perform the cleaning frequently to improve the thermal efficiency. However, if the frequency is too high, the anticorrosion film is removed. It is necessary to select an appropriate cleaning frequency that satisfies both the securing of the anticorrosion film and the removal of the biological film. Therefore, in a cooling tube made of a copper alloy, the number of times is usually reduced to 5 times / day in order to secure an anticorrosion film.

In order to improve the cleaning effect, the ball must be circulated well. However, if a foreign matter (for example, a dropped shell) blocks the tube, the circulation is hindered. In order to prevent this clogging of the pipes, it is desirable to use them together with a backwashing device or a shell removal device.

If the sponge ball 10 is worn out,
It is detected by the ball monitor 8 and replenished in the ball supply / extraction tank 9.

The ball supply / discharge tank 9 is vertically divided by a recovery strainer 23 which does not pass through the sponge ball 10, and in a normal circulation of the sponge ball 10, a ball circulation stop valve is provided. The ball circulation operation valve 17 is opened with the valve 18 closed, but when the sponge ball 10 is collected, the valve 18 is opened and the circulation pump 16 is operated with the valve 17 closed. Then, the cooling water circulates, but only the sponge ball 10 is stored and recovered on the recovery strainer 23 of the ball supply / extraction tank 9.

[0026]

As described above, the cooling thin tube 2 is intermittently operated by the sponge ball 10 several times a day.
In order to suppress the output of the cooling water supply pump for introducing cooling water into the cooling water supply chamber, the ball collecting strainer 6 is fully opened, so that the inlet side cooling water chamber 3 and the outlet side cooling water chamber 5 are provided. And the sponge ball 10 remaining in the ball return conduit 7 may pass through (approximately 2 to 5% of the total amount) and flow out to the surrounding sea area.

In particular, toxic paints and chlorine have been conventionally injected to prevent the adhesion of sea creatures, such as shellfish, which adhere to intake channels, condensers, and the like. Due to these prohibitions and restrictions, the adhesion of shellfish cannot be suppressed, and the number of shells that have fallen off increases, and it is necessary to fully open the ball collecting strainer 6 when the shellfish flows in. , The sponge ball 10 has been more frequently leaked.

By the way, the dumping of plastics directly into the sea area is prohibited by the international Convention on the Prevention of Pollution from the Ocean and the Marine Dumping Law of the domestic law. You will be dumped.

For this reason, a method of improving the ball collecting device and a method of collecting the ball in the cooling water discharge channel and the discharge port are considered. In these methods, a large number of small sponge balls are used. It is difficult to make the outflow of spills zero, and at the same time, the clogged state by falling shells also occurs,
If this closed state is continued for a long time, the output of the power generation unit itself is likely to be limited or an output stop accident is likely to occur, and in order to avoid these accidents, the sponge ball 10 is inevitably leaked. I'm fuzou.

On the other hand, as a method for preventing sea organisms from adhering to the ball circulation path in the sponge ball type washing apparatus, a ball is used.
A proposal has been made to prevent sea organisms from adhering to sponge balls and the like by mixing seawater sterilized by ultraviolet rays during the circulation operation (see Japanese Patent Application Laid-Open No. 62-294899).

However, such a proposed sponge boat
Even if the prevention of sea creatures from adhering to seawater, etc., the sponge ball itself has a low effect,
If the water is allowed to flow out into the surrounding sea area for the reasons described above, it is still inevitable that sponge balls are illegally dumped into the sea area, even if not as much as chlorine injection and antifouling paint.

[0032]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made with the utmost efforts to solve the above-mentioned problems. In particular, the present invention relates to an existing sponge ball type cooling tube cleaning apparatus for cooling. It is intended to be able to be executed immediately without modification as much as possible. The main points are: 1) a large number of sponge bottles together with cooling water on the inlet side.
After distributing and passing through a number of cooling tubes, the sponge balls are captured only, the cooling water is discharged to the sea area, and the captured sponge balls are introduced again into the cooling tubes. In a cooling tube cleaning apparatus for removing a biological film, slime, and the like on the inner surface of the cooling tube by continuous circulation, the sponge ball is a sponge ball made of biodegradable plastic. 2) The cooling tubing is used as the cooling tubing of the condenser of the power plant, and the ball storage device provided in the ball circulation path suppresses deterioration of the cleaning function due to biodegradation. 2. The cooling thin tube cleaning apparatus according to claim 1, further comprising a sterilizing device for irradiating ultraviolet rays or the like.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 shows a conventional ball supply and supply system shown in FIG.
A ball storage device 20 which is the same as an extraction tank (simply referred to as a ball storage device) 9 is shown, and other common parts (a condenser 1 for a power plant, a cooling tubule 2, a ball trapping strainer 6). etc)
Is not shown and described.

The ball storage device 20 comprises a bottomed tank body, and a lid 21 is provided on the upper surface thereof so as to be openable and closable. An ultraviolet irradiation device (for example, a low-pressure or medium-pressure mercury lamp having a quartz jacket as a light source and provided with a quartz jacket) 22 is provided on the lower surface of the lid 21 so as to be easily attached to an existing lid.

As shown in FIG. 2, the discharge pipe 24 of the circulation pump 16 faces the ball storage device 20, and the ball circulation operation valve 17 and the ball circulation stop valve 18 are provided. And pipes 25 and 26 communicating with each other.

The discharge side pipe 24 and the pipe 2
A recovery strainer 23 for partitioning the pipe 5 from the pipe 26 is provided at an angle.

Therefore, when the ball circulation is stopped, substantially all of the sponge balls circulated on the recovery strainer 23 are stored. During the ball circulation operation, all the sponge balls circulating are collected. Since the sponge balls pass through the recovery strainer 23, the microorganisms are sterilized by the ultraviolet irradiation device 22.

Here, the sponge ball of the present invention is not a sponge ball in which open cells are formed on a conventional natural rubber or synthetic rubber base, but a sponge ball on which a biodegradable plastic is opened in a base material. Use a tool.

Needless to say, this biodegradable plastic continuously exhibits excellent performance during use, is rapidly degraded by natural microorganisms after disposal, and finally has an organic component of soil. And plastics that turn into carbon dioxide and water. In particular, polylactic acid (a polymer of lactic acid, a low molecular weight compound (monomer) present in living organisms, etc.) It is produced by chemically dehydrating polycondensation reaction of generated lactic acid)
For example, a sponge ball continuously foamed using the polylactic acid resin fiber (for example, trade name “Lactron” manufactured by Kanebo Co., Ltd.) as a base material is used.

Of course, a sponge ball which is continuously foamed using an ester type polyurethane resin as a base material may be used.

When a conventional sponge ball based on natural rubber and a sponge ball based on the polylactic acid fiber of the present invention were compared in the sea area, the former was found to be 2-3.
It remained in its original form for years, but the latter lost its strength in 8 to 10 months and its original form disappeared.

Therefore, this sponge ball made of biodegradable plastic is used as usual for washing a conventional condenser for cooling a thin tube.
^When irradiated with ultraviolet light at about ² for 5 minutes / hour, the microorganisms in the sponge ball are sterilized while maintaining their strength.
Although it did not impair the cleaning effect at all, once it spilled into the sea, it was decomposed in about half a year, eliminating the reproach of illegal dumping.

If necessary, gold or steel sand or abrasive pieces may be adhered to the surface of the bioplastic sponge ball. In this case, the sponge ball is made of plastic.
Good adhesion can be achieved.

In the condenser using a titanium tube, sterilization by ozone injection may be performed instead of ultraviolet sterilization (see the biofouling experiment of the Tokyo Bay Tsurumi power plant described in "Ozone Water Treatment Technology"). ).

[0046]

According to the present invention, a biodegradable plastic sponge ball is used for sponge ball type washing of a cooling thin tube.
Even if some of the small sponge balls flow into the sea area, they are easily decomposed by microorganisms and do not pollute the sea area.

In particular, since the sponge ball is made of biodegradable plastic, the effect of the conventional sponge ball type cleaning is not reduced.
The sponge ball forming method disclosed in Japanese Unexamined Patent Application Publication No. 60-81493 or Japanese Utility Model Application Laid-Open No. 60-81493 can also be used as it is.

Further, by simply adding an ultraviolet irradiation device to the existing ball storage device, it is possible to prevent the deterioration of the cleaning function due to biodegradation of the sponge ball.

In particular, since a sterilizing device can be added to the existing one, it is possible to obtain excellent effects, to reduce the cost without worrying about separate piping and the like, and to be optimal for sterilizing the sponge ball itself.

[Brief description of the drawings]

FIG. 1 is a main part view of the present invention.

FIG. 2 is a conventional example.

[Explanation of symbols]

10 sponge ball, 20 ball storage device, 22
UV irradiation device

Claims (2)

[Claims] After distributing a large number of sponge balls together with cooling water on the inlet side to a large number of cooling tubes and introducing and passing them, only the sponge balls are captured and the cooling water is discharged to the sea area. A sponge ball, wherein the sponge ball is biodegraded by removing the biological film and slime from the inner surface of the cooling thin tube by continuous circulation in which the captured sponge ball is introduced again into the cooling thin tube; A cooling thin tube cleaning device comprising a sponge ball made of a conductive plastic. 2. The cooling thin tube is used as a cooling thin tube of a condenser of a power plant, and a ball storage device provided in a ball circulation path is provided with ultraviolet rays for suppressing deterioration of a cleaning function due to biodegradation. 2. The cooling thin tube cleaning device according to claim 1, further comprising a sterilizer for irradiation or the like.