JPH0679121A - System for making waste gas harmless - Google Patents

Abstract

PURPOSE:To provide a system for post-treating and making waste gas harmless immediate after the waste gas is discharged out of a semiconductor fabricating apparatus wherein the system is compact, does not leak the waste gas, and has a waste gas discharging duct through which the waste gas is discharged efficiently. CONSTITUTION:A system for making waste gas harmless is a system to remove harmful components contained in the waste gas and the system has a transverse-type parallel-flow wet-way harmful components removing apparatus 1 in the middle of a waste gas discharging duct 2 wherein the apparatus has two times or less wide cross section surface area of the waste gas discharging duct 2, treats waste gas at 2m/second or higher discharging flow rate, has good pressure loss efficiency since harmful components contained in the waste gas are made harmless by introducing washing water to flow in parallel, and thus can make the system compact. The parallel-flow wet-way harmful components removing apparatus 1 may be composed of static mixing apparatuses 3 or porous plates with venturi scrubbers with a plurality of holes and having a parallel-flow shower in the upper stream side. The waste gas discharging duct is divided in parallel into at least two ducts and the parallel-flow wet-way harmful components removing apparatus 1 may be put in each waste gas discharging duct 2 and the axis of the parallel-flow wet-way harmful components removing apparatus 1 is arranged in a straight line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas abatement system for removing exhaust gas emitted from a semiconductor manufacturing apparatus.

In the production of semiconductors, a large number of semiconductor production equipments and cleaning equipments that perform treatment by a wet process using chemicals such as acids and ammonia are used, and their exhausts are notably harmful.

Therefore, it is necessary to remove the harmful components from the exhaust gas discharged from these semiconductor manufacturing facilities before releasing them into the atmosphere. In a semiconductor factory, the exhaust gas is immediately removed from one or more semiconductor manufacturing facilities, and the safe exhaust gas after processing is passed through the ducts after that to improve the safety inside the factory. Wants

However, when an exhaust treatment device is installed in a factory, in order to ensure safety in maintenance, there is a demand for maintenance-free maintenance of the portion through which exhaust passes during continuous operation. In the future, it is also desired to recycle exhaust gas after treatment.

Further, it is desired to reduce the deterioration of the abatement function as much as possible even if the air volume and concentration of the exhaust gas change depending on the operating conditions of the semiconductor manufacturing equipment.

[0006]

2. Description of the Related Art FIG. 4 is an explanatory view of a conventional example. In the figure, 17 is a washing tower, 18 is an exhaust fan, 19 is an exhaust duct, and 20
Is a waste liquid pipe, 21 is a waste liquid receiving tank, 22 is a waste liquid pump, and 23 is an indoor cleaning tower.

In a conventional exhaust gas abatement system, as shown in FIG. 4, a cleaning tower 17 is installed outdoors, an exhaust fan 18 is installed immediately in front of it, and an exhaust duct 19 from a semiconductor manufacturing facility is exhaust fan by system. Piping up to 18 and drawing with negative pressure.

That is, the treatment of the waste liquid and the exhaust gas discharged from the semiconductor manufacturing equipment of the semiconductor factory is generally carried out by treating one or a plurality of semiconductor manufacturing equipments with no harmful exhaust gas as shown in FIG. 4 (a). An outdoor exhaust fan 18 in a semiconductor factory keeps the exhaust duct 19 at a negative pressure, and guides it to the washing tower 17 outdoors or to the rooftop to remove the waste liquid. It was sent to the waste liquid treatment equipment of No. 1 for processing.

Immediately after that, as shown in FIG. 4 (b), a small indoor cleaning tower 23 is provided in a semiconductor factory for semiconductor manufacturing equipment that emits particularly high-concentration harmful exhaust gas to perform cleaning processing. After that, it was often installed by insertion in a part of the exhaust duct 19 that exhausts air from other semiconductor manufacturing equipment to the outside.

Further, exhaust is also taken from the waste liquid receiving tank 21 of the waste liquid discharged from the semiconductor manufacturing apparatus so that harmful exhaust gas does not leak into the room. As described above, with these methods, harmful exhaust is constantly flowing in the exhaust duct 19, and even if the exhaust duct 19 has a negative pressure, check that there is no leakage due to the vortex flow generated at the bend of the exhaust duct 19. There was a need.

Further, since the exhaust ducts 19 are arranged for each system, the number of the exhaust ducts 19 is increased, the maintenance space is also increased, and improvement is desired. In a semiconductor factory, in order to arrange such an exhaust gas abatement system compactly and efficiently, a small co-current wet abatement device is installed indoors, and the exhaust gas after processing is collected to create a compact exhaust duct. It is necessary to discharge it at.

If the height of the exhaust gas abatement system including maintenance is set to 1.8 m or less, it becomes easy to secure the installation place. Therefore, with a cross-sectional area within twice the exhaust duct cross-sectional area, it can be installed compactly in the middle of the exhaust duct,
In addition, a compact horizontal co-current wet abatement system capable of processing at a space velocity of 2 m / sec or more is required.

Further, since the waste liquid piping can be reduced by efficiently utilizing the underground pit of the semiconductor factory, it contributes to the effective utilization of the space in the factory. Therefore, the underground pit or the liquid tank that also serves as a chamber is provided in the underground pit. Is desired.

[0014]

Therefore, it is necessary to increase the safety in the factory by flowing the safe exhaust gas after processing to the duct, and the exhaust gas generated in the bent part of the duct in the factory is required. It was necessary to check that the exhaust did not leak from the duct due to the swirling flow.

Further, since the exhaust ducts are arranged by system, the number of ducts increases, the maintenance space also increases, and improvements are desired. Therefore, it is an object of the present invention to provide a compact immediate-treatment exhaust gas abatement system that uses a horizontal co-current wet abatement device and that has no exhaust gas leakage and that efficiently ducts ducts.

[0016]

1 to 3 are block diagrams of an exhaust gas abatement system according to the present invention. In the figure, 1 is a co-current wet detoxifier, 2 is an exhaust duct, 3 is a static mixer, 4 is a perforated plate, 5 is a co-current shower, 6 is a multi-hole venturi scrubber, 7 is outlet piping, 8 is a chamber A combined liquid tank, 9 is a chamber part, 10 is a liquid tank part, 11 is a sheave tray, 12 is an exhaust fan, 13 is a pump, 14 is a right twist element, 15 is a left twist element, and 16 is a replenisher injection pipe.

In order to achieve the above object, the exhaust gas abatement system of the present invention has an exhaust duct 2 as shown in FIG. 1 (a).
By installing a horizontal co-current wet-type abatement system 1 that can be treated with a cross-sectional area of about 2 times or less, the height can be reduced to about 1.2 m and the exhaust fan can be made compact.
If the 12 is placed on the floor, the horizontal co-current wet type abatement machine 1 is installed at the same level as the exhaust fan 12 to facilitate the inspection.

That is, an object of the present invention is, as shown in FIG. 1 (a), an exhaust gas removal system for removing harmful components contained in exhaust gas, which is an exhaust gas removal system for removing harmful components contained in exhaust gas. The system 10 has a sectional area of the exhaust duct 2 of 2
It has a cross-sectional area of less than twice, and can process at an exhaust speed of 2 m / sec or more, and because the washing water flows in parallel to remove harmful components contained in the exhaust, the pressure loss efficiency is good, and the horizontal type is suitable for downsizing. By having the parallel flow wet type abatement device 1 in the middle of the exhaust duct 2, the parallel flow wet type abatement device 1 is shown in FIG.
As shown in FIG. 2, the static mixer 3 or the multi-hole venturi scrubber 6 having a perforated plate 4 and a co-current shower 5 upstream thereof as shown in FIG. As shown in FIG. 3 (f), the exhaust duct 2 is divided into at least two locations, and the co-current wet abatement device 1 is provided in each exhaust duct 2 and By arranging the axes of the wet type abatement machine 1 so as to be aligned on a straight line, as shown in FIG. 1 (b),
Wind velocity of 0.2 m passing through the outlet pipe 7 of the co-current wet type abatement system 1.
Since it is connected to the chamber / liquid tank 8 that decelerates to less than 1 / second, as shown in FIG. 3 (g) or FIG. This is achieved by having a sieve tray 11 between the tank section 10 and the tank section 10.

[0019]

In the present invention, a horizontal co-current wet type abatement device having a cross-sectional area of less than twice that of the duct and capable of processing at an exhaust velocity of 2 m / sec or more is mounted in the middle of the exhaust duct. Can be made compact.

Further, the co-current wet abatement device is a static mixer,
Alternatively, if a multi-hole venturi scrubber is used, the exhaust gas is always washed by the cleaning liquid flowing in parallel, and the scrubber etc. will not be clogged even if a dedicated anti-clogging spray is not installed, and the exhaust gas abatement system can be operated continuously. It will be possible.

The static mixer or the multi-hole venturi scrubber can operate at a space velocity of 2 m / sec or more, and is effective for continuous operation because it has no driving part.

Further, by collecting exhaust ducts, harmless exhaust can be discharged compactly, and by providing a chamber / liquid tank, mist can be removed and exhaust ducts can be collected at one time, and recovered mist can be used as a circulating liquid as it is. There is.

[0023]

1 to 3 are block diagrams of an exhaust gas abatement system according to the present invention. The exhaust gas abatement system according to the present invention is shown in FIG.
As shown in (a), the horizontal parallel-flow wet abatement device 1 capable of processing with a cross-sectional area within about twice as large as the duct is provided, and by installing it in the middle of the exhaust duct 2, the height becomes 1. When the exhaust fan 12 can be made compact to about 2 m and the exhaust fan 12 is installed indoors, the exhaust fan 12 is a horizontal co-current wet detoxifier 1
It was installed at the same level as above to facilitate inspection.

Further, as shown in FIG. 1 (b), in the static mixer 3, it is more efficient to provide the cleaning liquid injection port at the intermediate portion other than the upstream side inlet. The internal structure of the static mixer 3 is shown in FIG.

The multi-hole venturi scrubber 6 shown in FIG. 2D is composed of a perforated plate 4 having a co-current shower 5 upstream. FIG. 2E shows the internal structure of the perforated plate 4 of the multi-hole venturi scrubber 6.

When the static mixer 3 and the multi-hole venturi scrubber 6 are used horizontally, in order to prevent the flow of the co-current shower 5 from becoming non-uniform due to gravity, 500 mm square
It is desirable to use it with a size less than that.

Further, as shown in FIG. 3 (f), when the exhaust duct 2 is divided into a plurality of parts and a plurality of horizontal co-current wet abatement devices 1 are provided in the middle of each exhaust duct 1, maintenance is required. Compactness can be maintained by arranging the axes of the parallel-flow wet-type remover on a straight line for the sake of simplicity.

The harmless exhaust gas that has been treated by the horizontal parallel flow wet type excluding device 1 can be exhausted compactly by consolidating the exhaust ducts 2. Further, when removing mist, it is effective to reduce the passing wind speed to 0.2 m / sec or less and change the direction. However, if it is installed in the middle of the duct, it is difficult to secure the installation space.

Therefore, in a semiconductor factory, as shown in FIG. 1 (b), a common underground pit is used to provide a chamber / tank 8 for removing mist and consolidating exhaust ducts 2 at once. Pump the collected mist as it is 13
It is possible to provide the advantage that it can be used as a circulating fluid.

Further, if the treated exhaust and the high-concentration circulating liquid are brought into contact with each other, there is a risk of re-evaporation due to the balance of vapor pressure,
In this case, as shown in FIG. 3 (g), the treated exhaust gas and the high-concentration circulating liquid are separated using the sieve tray 11 of a perforated plate, and the replenishing liquid is supplied from the replenishing liquid injection pipe 16 onto the sieve tray 11. Improved.

In addition to this, in this system, the chamber-use liquid tank 8 can also be used as a low-concentration waste liquid receiving tank, so that the system of the entire factory can be made compact. Furthermore, if the treated exhaust gas is secondarily treated with a replenisher, the removal efficiency can be further improved. In that case, a perforated plate cleaning method with a small liquid / gas ratio is appropriate.

Therefore, as shown in FIG. 3 (h), an exhaust outlet after the treatment is connected between the sieve tray 11 made of a perforated plate and the liquid surface of the liquid tank section 10 by the horizontal co-current wet abatement device 1. Then, the mist can be removed by performing the secondary treatment. As a method for removing mist, a collision type mist removing section and a cyclone are added to further improve the removing effect.

[0033]

As described above, according to the present invention,
By installing a horizontal compact co-current wet abatement device in the middle of the exhaust duct, the height can be made compact, and the co-current wet abatement device is composed of a static mixer or a multi-hole venturi scrubber. By doing so, the exhaust gas is always washed by the washing liquid flowing in parallel, and clogging does not occur.

As a result, the present invention greatly contributes to the compactness and high efficiency of the exhaust gas abatement system.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an exhaust gas abatement system of the present invention (No. 1)

FIG. 2 is a configuration diagram of an exhaust gas abatement system of the present invention (part 2)

FIG. 3 is a configuration diagram of an exhaust gas abatement system of the present invention (part 3)

FIG. 4 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 1 is a co-current wet detoxifier 2 is an exhaust duct 3 is a static mixer 4 is a perforated plate 5 is a co-current shower 6 is a multi-hole venturi scrubber 7 is an outlet pipe 8 is a chamber / liquid tank 9 is a chamber 10 Tank part 11 is sieve tray 12 is exhaust fan 13 is pump 14 is right twist element 15 is left twist element 16 is replenisher injection pipe

Claims (5)

[Claims] 1. An exhaust gas abatement system (10) for removing harmful components contained in exhaust gas, which has a cross-sectional area less than twice the cross-sectional area of an exhaust duct (2) and an exhaust speed of 2 m. The horizontal co-current wet detoxifier (1) is suitable for downsizing because it can be processed at a speed of at least 1 second / sec. An exhaust gas abatement system characterized by being provided in the middle of (2). 2. A multi-hole venturi scrubber comprising a static mixer (3) or a perforated plate (4) and a co-current shower (5) upstream thereof. The exhaust gas abatement system according to claim 1, wherein the exhaust gas abatement system is composed of (6). 3. The exhaust duct (2) is divided into at least two or more locations in parallel, and the co-current wet abatement device (1) is provided in each of the exhaust ducts (2), and The exhaust gas abatement system according to claim 1 or 2, wherein the flow-wet abatement device (1) is arranged such that the axes thereof are aligned. 4. The outlet pipe (7) of the co-current wet type abatement device (1).
4. The exhaust gas abatement system according to claim 1, wherein the exhaust gas abatement system is connected to a chamber / liquid tank (8) that reduces the passing air velocity to 0.2 m / sec or less. 5. The chamber section of the chamber-use liquid tank (8)
The exhaust gas abatement system according to any one of claims 1 to 4, further comprising a sieve tray (11) between the liquid tank portion (10) and the liquid tank portion (10).