JPH07246316A - Underwater cooler for high-temperature pcb waste gas - Google Patents

Abstract

PURPOSE:To provide an underwater cooler to efficiently, forcedly and rapidly cool a high-temp. PCB waste gas below the chemical reaction temp. at which dioxine is generated within the necessary reaction time by passing the waste gas through the cooling water at the lower part of a primary cooling tower. CONSTITUTION:A gas blowoff pipe 24 with the wall in the middle in the longitudinal direction pierced with many injection holes is hung down into the lower cooling water 5 and fixed to the lower face of the bottom fixing plate 22 of a high-temp. waste gas chamber 3 at the upper part of a cooling water tank, and the high-pressure cooling water 5 is injected downward from the blowoff ports of a high-pressure water chamber 26 provided around the upper part of the 24. Consequently, the many small bubbles of the high-temp. gas passed through the turbulent flow of the cooling water 5 are rapidly cooled and discharged from the vertical through-hole 20 at the center of the chamber 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a PCB gas incinerator in a PCB disposal process for preventing pollution of the global environment due to disposal of a harmful substance PCB (polychlorinated biphenyl) which has been conventionally used as a heat medium or the like. The present invention relates to an underwater cooling device in the forced rapid cooling device for high-temperature exhaust gas.

[0002]

2. Description of the Related Art Conventionally, as a method for disposing of pollutant PCB contained in equipment such as large transformers and high voltage condensers by incineration, in Japan, combustion temperatures of 1, 1
It was the minimum necessary condition for carrying out the method that the decomposition efficiency was 99.9999%, that is, 6-nine was confirmed by conducting a test at 50 ° C., retention time of 2 seconds, and excess oxygen of 3%.

In order to efficiently achieve these conditions with a relatively small apparatus, for example, a PCB waste oil combustion treatment method by the same inventor of the present invention (Japanese Patent Application No. 5-241).
No. 419) and a waste oil combustion device (Japanese Patent Application No. 5-229067) related to this method are proposed and disclosed.

However, in the above conventional proposals, the combustion gas discharged by incineration of the PCB gas is burned and decomposed at a high temperature of 1,400 ° C. or higher, for example, 1,800 ° C., Exhaust gas from the incinerator has a temperature of 1,600 ° C. or higher, and when cooled, dioxin, which is a harmful substance, is generated in a temperature range of 700 to 250 ° C. For this reason, it is necessary to take a separate dioxin removing means.

In order to prevent the generation of these dioxins, the gas temperature is kept at 250 ° C. or lower within 1/10 seconds, which is the chemical reaction time of dioxins, by forcibly and rapidly cooling the high temperature exhaust gas. Therefore, a forced rapid cooling device for suppressing the generation of dioxin was disclosed by the same inventor of the present invention in Japanese Patent Application No. 6-1179.
No. 2 discloses the application.

This method / apparatus is an apparatus for rapidly cooling high-temperature exhaust gas of 1600 ° C. or higher from a PCB gas incinerator, which comprises primary and secondary cooling means, and the primary cooling means is A guide means for introducing the high-temperature exhaust gas to pass through the cooling water; a first high-pressure water spray means for cooling the temperature of the passing gas to 250 ° C. or lower within 1/10 seconds; With the outlet means for discharging the cooled gas, the secondary cooling means includes a cooling water coil tube, a second high-pressure water spray means for cooling the coil tube, and the primary cooling means. A high-pressure water pump for supplying cooling water into the cooling-water coil tube, and a high-pressure water pipe for supplying the cooled high-pressure water in the coil tube to the first high-pressure water spray means of the primary cooling means. Cormorants are those that are configured.

An outline of the forced rapid cooling device according to one embodiment of the proposed invention will be described with reference to FIG. This cooling device consists of primary and secondary cooling towers 1, 9.

Numeral 1 is a primary gas cooling tower, which is 1,80 in the previous step.
First, high-temperature exhaust gas 2 of 1,600 ° C. or higher from a waste PCB gas incinerator, which is burned and decomposed at a high temperature of 0 ° C., is first introduced into the underwater cooling device 1a through a duct. When these exhaust gases 2 are cooled, dioxin is generated in the temperature range of 700 to 250 ° C., so that the chemical reaction time of the generation is 1/10.
It is intended to rapidly cool to 250 ° C. or lower within a second.

A hot exhaust gas chamber 3 is constructed so that the hot exhaust gas 2 is sucked from the cooled gas outlet 4 at the top of the tower 1 at a static pressure of -500 mmHg. 5a is a guide valve for the cooling water 5 stored at the bottom of the tower 1, 6 is an obstruction plate, 7 is a high-pressure water pipe, 8 is a first high-pressure water spray device, 12 is a high-pressure water pump, and 13 is a float valve 13a. The water level adjusting tank 15 has a demister / separator for removing residual vapor and dust in the tower 1.

Further, the secondary cooling tower 9 has a cooling water coil tube 9a in the tower, and the cooling water 5 at the bottom of the primary cooling tower 1 is supplied to the cooling water coil tube 9a from below by a high-pressure water pump 12. It is pressure-fed and guided from the upper end of the pipe to the high-pressure water spray device 8 in the primary cooling tower through the high-pressure water feed pipe 7. 10
Is a blower for ventilating the high-pressure spray device 8 from above to below.

The water in the cooling coil tube 9a in the secondary cooling tower 9 is supplied by a high pressure spray device 17 in which the bottom cooling water 16 (14 is a water level adjusting tank with its float valve 14a) is guided by a high pressure water pump 11. The high-temperature gas 2 that has been cooled and guided to the second high-pressure spray device 8 in the primary cooling tower 1 through the high-pressure water supply pipe 7 and has passed through the cooling water 5 is rapidly cooled.

As described above, in the primary cooling tower 1, the high temperature of the exhaust gas 2 is rapidly cooled in the cooling water 5 and by the high-pressure spray 8 to change the high heat of the gas to steam, and the heat of vaporization removes the heat of the gas. Therefore, a huge amount of water vapor is generated. In order to suppress this, the high-pressure water spray 8 is struck downward from these steams to lower the steam temperature.
Inside, gas cooling and water vapor cooling are performed. The inside of the tower 1 is hermetically sealed, and hermetically sealed so that neither exhaust gas nor water vapor leaks to the outside.

To summarize the above operation, the cooled gas outlet 4
The high-temperature exhaust gas 2 at 1,600 ° C. drawn into the gas chamber 3 of the primary cooling tower 1 at a static pressure of −500 mmHg is the shielding plate 6
It passes under the cooling water 5 and tries to proceed to the outlet 4 through the guide valve 5a. At this time, the water 5 and the high-temperature exhaust gas 2 come into contact with each other, and a large amount of steam generated is highly heated by the high-pressure water spray 8 from the high-pressure water pipe 7 (cooling water in the pipe is 50 ° C. or lower here). It is sprayed on water vapor for rapid cooling, and the water amount of this spray 8 is, for example, 33 l / s for 1 m ^{3 of} gas, that is, 33 l is 33 m per second.
^It is configured to spray ³ gases and its water velocity is 1
It is 6 m / s.

The cooling water in the high-pressure water supply pipe 7 is circulated in the secondary cooling tower 9 by the high-pressure water pump 11, and the cooling tower 9 cools this cooling water to 50 ° C. or less by the cooling water coil pipe 9a. is doing. The water 16 at the bottom of the tower is the high-pressure water pump 11
Thus, the high-pressure spray water sent to the high-pressure spray 17 and ejected from the high-pressure spray 17 is configured to exchange heat with the surrounding atmosphere by the large blower 10.

With the above cooling device, the high temperature exhaust gas 2 is reduced to 1
Within 10 seconds, it is rapidly cooled to below 200 ° C (actually about 100 ° C), and without producing dioxin, remove harmful components such as NO _{x in the} next step and emit it to the atmosphere without pollution. It is intended to be possible.

[0016]

However, in the above-mentioned conventional proposals, the high-temperature exhaust gas 2 is first dipped in the cooling water 5 in the underwater cooling device 1a of the primary gas cooling tower 1. When a gas bubble is generated and is forced to be rapidly cooled by the high-pressure spray 8 in a short time of 1/10 s or less, as in the above-described embodiment, by simply passing the water through the guide valve 5a, The plurality of generated high temperature gas bubbles immediately merge into a large bubble, and because of the high temperature, the levitation speed is extremely high, and the bubbles tend to rapidly rise above the water. Therefore, they contact the cooling water 5. If the ratio of the cooling area and time to the amount of bubble gas is extremely small and the cooling effect of the water 5 is reduced, an attempt to obtain a desired cooling rate inevitably entails a considerable upsizing of the related apparatus. There is a problem to say.

The present invention has been made in view of the problems of the above-described conventional proposals, and it is possible to generate a large number of small-diameter high-temperature gas bubbles without requiring the enlargement of the related apparatus. The purpose is to provide means for increasing the cooling effect by passing these through a longer path in the cooling water 5.

[0018]

For this reason, in the present invention, an underwater cooling device for this type of high temperature PCB exhaust gas is provided with an upper shield plate and a lower shield plate provided to horizontally and sealingly cover the upper part of the cooling water tank. A high temperature exhaust gas chamber which is formed between the mounting plate and a part of which has a high temperature exhaust gas inlet and a vertical opening portion in the center thereof, and a plurality of circular holes on the mounting plate, which communicate with each other, Each gas blow-out pipe is fixed so as to hang down in the cooling water, and a large number of gas injection holes are bored in the pipe wall at the middle part of its length, and it is arranged close to the upper periphery of each gas blow-out pipe. , A high-pressure water chamber having a plurality of downward outlets, a high-pressure pump means for delivering the high-pressure water of the cooling water to each high-pressure water chamber, and a high-pressure water pipe, by the configuration, It is an attempt to achieve the purpose.

According to the underwater cooling apparatus of the present invention as described above, in the high temperature PCB exhaust gas, a large number of small air bubbles are retained in the turbulent flow of the cooling water for a relatively long time, so that the cooling efficiency is extremely high. The temperature of the high-temperature exhaust gas from the PCB gas incinerator of waste PCB liquid can be controlled without increasing the size of related equipment, and the chemical reaction temperature range for generating dioxin is 700 to
It is possible to efficiently and rapidly cool to 250 ° C or less within the reaction time of 1/10 s, and it is possible to move to the next harmful substance removal step without generating dioxin and realize pollution-free atmospheric emission. .

[0020]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a vertical cross-sectional view (a) and an AA cross-sectional perspective view (b) of an underwater cooling device section of a high temperature exhaust gas inlet of a primary cooling tower of a PCB high temperature exhaust gas forced cooling device according to the present invention,
2 is an enlarged view of part B of FIG. 1 (a) and its C
-C sectional perspective view (b) is shown. The same (corresponding) constituent elements as those in FIG. 3 of the conventional proposal example are represented by the same reference numerals, and the duplicated description thereof will be omitted.

(Structure) In FIG. 1, 1b is a structural view of an embodiment of the underwater cooling apparatus according to the present invention which forms the lower part of the primary gas cooling tower. 2 is a high temperature PC of about 1600 ℃
B is an inlet portion of the exhaust gas, 3 is an upper shielding plate 21 and a lower mounting plate 22 each having a substantially square opening 20 in the central portion, and an outer wall of the cooling tower 1 and a vertical opening side wall 2.
3 shows a hot exhaust gas chamber closed by 3.

As shown in FIG. 1 (b), the mounting plate 22 is provided with a large number of small-diameter circular holes, and below each of the circular holes, there is a gas blow-off pipe having the same diameter and a predetermined length. 24
Are fixed so as to hang in the cooling water 5. A large number of small-diameter gas injection holes 25 are formed relatively densely in the circumferential wall of each gas outlet pipe 24 in the longitudinal middle portion.

On the back surface of the mounting plate 24, the annular high-pressure water chambers 2 are provided so as to be close to and surround the respective gas outlet pipes 24.
6 are provided, and the lower surface thereof is provided with a plurality of air outlets 27 downward. Each of these high pressure water chambers 26
Are communicated so that high-pressure cooling water is supplied via high-pressure water pipes 29 by high-pressure water pumps 28 arranged outside the cooling water tank.

(Operation) Next, an underwater cooling operation of the high temperature exhaust gas with the above-mentioned structure will be described.

The high-temperature exhaust gas introduced into the high-temperature exhaust gas chamber 3 from the inlet of the high-temperature exhaust gas 2 is discharged into the cooling water 5 from each gas outlet pipe 24 due to its pressure, and a part of it is discharged into each pipe 2.
A large number of small bubbles are continuously formed through a large number of gas injection holes 25 provided in the intermediate portion of No. 4 and are ejected into the water to diffuse and contact the cooling water 5.

On the other hand, from the annular high-pressure water chambers 26 disposed above the gas outlet pipes 24, high-pressure water is jetted into the cooling water 5 in a substantially downward direction around the pipes 24. , The small gas bubbles of each of the above gas that have flown out into the water are sucked in by the downward convection, and there is no opportunity for the small bubbles to coalesce and form a large size, so there is a relatively long distance in the turbulent flow of cooling water. It functions to stay for a relatively long time and reduce the temperature of the outer surface of the bubble very efficiently.

According to the result of the experiment, the time 10 /
It was confirmed that the high temperature exhaust gas at 1600 ° C. at the inlet was reduced to 250 ° C. at the water surface of the cooling water 5 at the discharge portion and to about 75 ° C. at the cooled gas outlet portion 4 in FIG. 3 within 1000 seconds.

The structure of the present invention is not limited to the embodiment shown in the drawings, but the diameter and number of each gas outlet pipe 24, the arrangement density, the distribution of the gas injection holes 25, and the high pressure water chamber. It goes without saying that there is no problem even with a wide variety of modifications such as the shape of 26 and the number and directionality of the outlets 27 for realizing the principle of the present invention.

[0029]

As described above, according to the submersible cooling system of the present invention, a large number of small-sized bubbles in the high temperature PCB exhaust gas stay in the turbulent flow of the cooling water for a relatively long time. The temperature of the high temperature exhaust gas from the PCB gas incinerator of waste PCB liquid is required to be in the chemical reaction temperature range of 700 to 250 ° C or less for generating dioxins, with extremely good cooling efficiency and without upsizing of related equipment. Time 1/10
It is possible to perform forced rapid cooling within s, and to move to the next harmful substance removal step without emission of dioxin, and to realize pollution-free atmospheric emission.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an underwater cooling device according to the present invention and its AA cross-sectional perspective view.

FIG. 2 is an enlarged view of FIG. 1B part and its CC cross-sectional perspective view.

FIG. 3 is a schematic explanatory diagram of an embodiment of a conventional forced rapid cooling device of the proposed invention.

[Explanation of symbols]

 1 Primary Gas Cooling Tower 1a, 1b Underwater Cooling Device 2 High Temperature Exhaust Gas 4 Cooled Gas Outlet 5,16 Cooling Water 5a Cooling Water Guide 7 High Pressure Water Pipe 8,17 High Pressure Water Spraying Device 9 Secondary Cooling Tower 9a Cooling Water Coil Pipe 11 , 12 high-pressure water pump 20 opening 21 shielding plate 22 mounting plate 24 gas blow-out pipe 25 gas injection hole 26 high-pressure water chamber 27 blow-out port 28 high-pressure water pump 29 high-pressure water pipe

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 16, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

However, in the above conventional proposals, the combustion gas discharged by incineration of the PCB gas is burned and decomposed at a high temperature of 1,400 ° C. or higher, for example, 1,800 ° C., Exhaust gas from the incinerator has a temperature of 1,600 ° C. or higher, and when cooled, dioxin, which is a harmful substance, is generated in the temperature range of 700 to 200 ° C. For this reason, it is necessary to take a separate dioxin removing means.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

In order to prevent the generation of these dioxins, the gas temperature is kept at 200 ° C. or lower within 1/10 seconds, which is the chemical reaction time of dioxins, by forcibly and rapidly cooling the high-temperature exhaust gas as described above. Therefore, a forced rapid cooling device for suppressing the generation of dioxin was disclosed by the same inventor of the present invention in Japanese Patent Application No. 6-1179.
No. 2 discloses the application.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

This method / apparatus is an apparatus for rapidly cooling high-temperature exhaust gas of 1600 ° C. or higher from a PCB gas incinerator, which comprises primary and secondary cooling means, and the primary cooling means is Guide means for introducing the high-temperature exhaust gas to pass through the cooling water, first high-pressure water spray means for cooling the temperature of the passing gas to 200 ° C. or lower within 1/10 seconds, and With the outlet means for discharging the cooled gas, the secondary cooling means includes a cooling water coil tube, a second high-pressure water spray means for cooling the coil tube, and the primary cooling means. A high-pressure water pump for supplying cooling water into the cooling-water coil tube, and a high-pressure water pipe for supplying the cooled high-pressure water in the coil tube to the first high-pressure water spray means of the primary cooling means. It is configured as follows.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Numeral 1 is a primary gas cooling tower, which is 1,80 in the previous step.
First, high-temperature exhaust gas 2 of 1,600 ° C. or higher from a waste PCB gas incinerator, which is burned and decomposed at a high temperature of 0 ° C., is first introduced into the underwater cooling device 1a through a duct. When these exhaust gases 2 are cooled, dioxin is generated in the temperature range of 700 to 250 ° C., so that the chemical reaction time of the generation is 1/10.
It intends to rapidly cool to 200 ° C or less within a second.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

[0019]

According to the water cooling device according to the action described above of the present invention as, since as the hot PCB exhaust gas staying in the turbulent flow of a large number of small bubbles relatively long cooling water, very cooling efficiency Good, and the waste P
The temperature of the high temperature exhaust gas from the PCB gas incinerator for CB liquid is
Chemical reaction temperature range for generating dioxins 700 to 20
It is possible to efficiently and rapidly cool to 0 ° C or less within 1 / 10s of the time required for the reaction, and it is possible to move to the next harmful substance removal step without generating dioxin and realize pollution-free atmospheric emission. .

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

[0029]

As described above, according to the submersible cooling system of the present invention, a large number of small-sized bubbles in the high temperature PCB exhaust gas stay in the turbulent flow of the cooling water for a relatively long time. The temperature of the high temperature exhaust gas from the PCB gas incinerator of waste PCB liquid is required to be in the chemical reaction temperature range of 700 to 200 ° C or less for generating dioxin, with extremely good cooling efficiency and without upsizing of related equipment. Time 1/10
It is possible to perform forced rapid cooling within s, and to move to the next harmful substance removal step without emission of dioxin, and to realize pollution-free atmospheric emission.

Claims (1)

[Claims] 1. A high temperature exhaust gas inlet formed between an upper shielding plate and a lower mounting plate, which are provided so as to horizontally and hermetically cover an upper portion of a cooling water tank, a part of which is provided with a high temperature exhaust gas inlet, and a vertical opening is provided at a central portion thereof. And a plurality of circular holes on the mounting plate, each of which is fixed so as to hang down into the cooling water below, and a large number of gas jets are formed on the pipe wall in the middle of its length. Each gas outlet pipe having a hole, a high-pressure water chamber having a plurality of downward outlets arranged near the upper portion of each gas outlet pipe, and the cooling in each high-pressure water chamber. An underwater cooling device for high-temperature PCG exhaust gas, comprising high-pressure pump means for delivering high-pressure water and high-pressure water piping.