JPH0663335A - Exhaust decontamination system - Google Patents

Abstract

PURPOSE:To provide the immediate-post treatment exhaust decontamination system which takes advantage of the respective features of a parallel flow wet process decontamination device and a counter current wet process decontamination device, makes up weak point and is compact as the exhaust decontamination system which decontaminates the exhaust discharged from an apparatus for production of semiconductors. CONSTITUTION:This exhaust decontamination system is constituted by disposing, in series, the parallel flow wet process decontamination device 1 and counter current wet process decontamination device 20, which are respectively used to remove the harmful components included in the exhaust, the former in a front stage and the latter in a rear stage. The above-mentioned system is provided with a washing liquid replenishing port 22 for replenishing a washing liquid in the upper part of the counter current wet process decontamination device 20 and is provided with a washing liquid recovering tank 20 for recovering the washing liquid in the lower part of the counter current wet process decontamination device 20. Further, the system has a function to circulate and supply the washing liquid to the parallel flow wet process decontamination device 1 by a washing liquid circulating pump 3 from the washing liquid recovering tank 2.

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 harmful components from the exhaust gas discharged from these semiconductor manufacturing facilities before releasing them into the atmosphere. The exhaust exclusion system is 1
Or, the exhaust gas is removed immediately after that for multiple semiconductor manufacturing facilities, etc., and the deterioration of the abatement function is reduced as much as possible even if the air volume and concentration of the exhaust gas change depending on the operating conditions of the manufacturing equipment. It is desired to let them do.

[0004]

2. Description of the Related Art FIG. 3 is an explanatory view of a conventional example. Exhaust gas abatement systems (scrubbers) can be roughly divided into co-current / wet abatement devices and countercurrent / wet abatement devices.

The co-current / wet detoxifier includes a jet scrubber as shown in FIG. 3 (a) or a static mixing scrubber as shown in FIG. 3 (b). Since the cleaning liquid and the exhaust flow in parallel, the scale can be cleaned at all times, and the scale is not clogged and high-concentration exhaust treatment can be performed.

However, a gas-liquid separation mechanism is required separately,
Generally, a gas-liquid separating mechanism such as a demister is provided upward, so that it is not compact. Also, since the amount of cleaning liquid is large, it is not suitable to always clean with a new liquid because the amount of waste liquid processed increases.

The countercurrent / wet detoxifier includes a packed tower scrubber as shown in FIG. 3 (c) or a perforated plate type scrubber as shown in FIG. 3 (d), which has a small gas-liquid ratio. Suitable for low concentration treatment. Since it is a countercurrent type and a gas-liquid separation mechanism such as a demister can be installed in the upper part, it has the feature of being compact.

However, since clogging occurs due to adhesion of scale, continuous operation of semiconductor manufacturing is hindered. Also,
The perforated plate tower scrubber has a problem that the removal efficiency tends to fluctuate due to changes in the air volume.

[0009]

In a semiconductor factory, exhaust gas is removed immediately after one or a plurality of semiconductor manufacturing facilities and the like, and a safe exhaust gas after processing is passed through a duct thereafter. We want to improve safety in the factory.

However, when installing an exhaust treatment device in a factory,
In order to ensure maintenance safety, maintenance-free parts where exhaust gas passes during continuous operation are required. From an environmental point of view, it is also desired to remove white smoke from the scrubber, and in the future, it will be desirable to recycle exhaust gas after treatment.

Therefore, an object of the present invention is to provide a compact immediate aftertreatment exhaust gas abatement system that compensates for the features and weaknesses of the co-current / wet abatement device and the countercurrent / wet abatement device.

[0012]

1 and 2 are block diagrams of an exhaust gas abatement system of the present invention. In the figure, 1 is a co-current / wet removal device, 2 is a cleaning liquid recovery tank, 3 is a cleaning liquid circulation pump, 4 is a concentrating device, 5 is a cleaning liquid, 6 is a replenishing liquid, 10 is a semiconductor manufacturing facility for discharging process exhaust gas, 11 is a static pressure detector,
12 is a damper, 20 is a countercurrent / wet eliminator, 21 is a demister, 22
Is a cleaning liquid supply port, 23 is a heating unit, 24 is an exhaust fan, 25 is a bypass duct, 26 is an air flow controller, 27 is a damper, and 28 is a damper.

In order to achieve the above object, the first method of the exhaust gas abatement system of the present invention is, as described above, that a large amount of cleaning liquid is circulated in the pre-stage cocurrent / wet abatement device 1 for the harmful exhaust gas. Then, the high-concentration harmful exhaust gas is subjected to the primary treatment, and thereafter, in the latter stage, it is advancedly treated by the countercurrent / wet abatement device 20 having a small gas-liquid ratio. Immediately after collecting 5 in the recovery tank 2 and using it as the cleaning liquid 5 for the co-current / wet detoxifier 1 in the previous stage, it is characterized by advanced processing of exhaust gas, compactness, and no maintenance during continuous operation. A treated emissions exclusion system is provided.

That is, as shown in FIG. 1, the object of the present invention is to provide a countercurrent / wet abatement device 20 in front of a co-current / wet abatement device 1 for removing harmful components contained in exhaust gas. Is an exhaust abatement system arranged in series in the latter part of the
Cleaning liquid replenishment port for supplying the cleaning liquid 5 to the upper part of the wet detoxifier 20
22 and the cleaning liquid 5 in the lower part of the countercurrent / wet abatement device 20.
By providing a cleaning liquid recovery tank 2 for collecting the cleaning liquid, and further having a function of circulatingly supplying the cleaning liquid 5 from the cleaning liquid recovery tank 2 to the co-current / wet abatement device 1 by the cleaning liquid circulation pump, By providing the heating unit 23 on the treated exhaust outlet side of the wet type abatement device 20, and as shown in FIG. 2, an exhaust fan 24 is provided on the treated exhaust outlet side of the countercurrent / wet type abatement device 20. From the duct 5 after the outlet of the exhaust fan 24, the parallel flow / wet abatement device 1 and the countercurrent / wet abatement device
By providing a bypass in the middle of 20 and by providing an air volume controller 26 that variably returns the circulating exhaust gas of the bypass 25 in response to a signal from the static pressure detector 11, the cleaning liquid 5 of the exhaust gas exclusion system is also provided. A concentrating device 4 is provided on the discharge side of the cleaning liquid circulation pump 3 of the co-current / wet type decontamination device 1 using water, and a regenerant liquid 8 is blown with a condensate liquid 7 to regenerate the regenerant liquid 8 of the co-current / wet type abatement device 1 By supplying as the cleaning liquid 5, a bypass 25 is further provided between the cocurrent / wet abatement device 1 and the countercurrent / wet abatement device 20, and the exhaust inlet of the cocurrent / wet abatement device 1 is provided. The bypass from the side through damper 12
A duct 25 connected to 25, a duct connected from the bypass duct 25 to the exhaust outlet of the countercurrent / wet abatement device 20 via a damper 27, and the co-current / wet abatement device 1 and the countercurrent /
This is achieved by providing a damper 28 for partitioning the wet abatement machine 20.

[0015]

In the present invention, in the first method, the harmful exhaust gas is subjected to the co-current / wet detoxifier in the preceding stage to circulate a large amount of the cleaning liquid to perform the primary treatment of the highly concentrated harmful exhaust gas, and then in the subsequent stage. For high-performance treatment with a countercurrent / wet detoxifier with a small gas-liquid ratio, new cleaning liquid is constantly replenished for detoxification, the cleaning liquid is collected in a recovery tank, and the cleaning liquid for the co-current / wet detoxifier at the previous stage is collected. As a result, it is possible to perform high-level processing of exhaust gas, make it compact, and perform maintenance-free operation during continuous operation.

Further, the second method makes it possible to improve the removal performance of the exhaust gas abatement system for immediate treatment and remove white smoke.
In the third method, when a perforated plate type scrubber is used for the countercurrent / wet abatement system, the air volume fluctuation can be stabilized.

In the semiconductor cleaning process, water is sometimes used for the treatment of acidic exhaust, disliked by alkali metal contamination such as sodium. In that case, it is required to keep the concentration of the cleaning substance in the cleaning water low in order to prevent the cleaning efficiency from decreasing.

Therefore, in the fourth method, for example, a concentrating device such as a reverse osmosis membrane device or an ion dialysis device can be supplied to the cocurrent / wet detoxifier with the regenerated water to stabilize the detoxification capacity. In order to maintain continuous operation of the semiconductor manufacturing process, if a part of the exhaust gas abatement system immediately after treatment is stopped due to an emergency failure,
At least one of the co-current / wet abatement device and the countercurrent / wet abatement device is required to operate normally and be treated to a value lower than the regulation value of the exhaust gas concentration.

Therefore, stable operation can be maintained by the fifth method.

[0020]

1 and 2 are block diagrams of an exhaust gas abatement system according to the present invention. In the figure, 1 is a co-current / wet detoxification device, 2 is a cleaning liquid recovery tank, 3 is a cleaning liquid circulation pump, 4 is a concentrating device, 10 is a semiconductor manufacturing facility that discharges exhaust gas requiring processing, 11 is a static pressure detector, 12 Is a damper, 20 is a countercurrent / wet detoxifier, 21 is a demister, 22 is a cleaning liquid supply port, 23 is a heating part, 24 is an exhaust fan, 25 is a bypass duct, 26 is an air flow controller, 27 is a damper, 28 is 28 It's a damper.

First, second, third, fourth and fifth embodiments of the exhaust gas abatement system according to the present invention will be described with reference to the configuration diagrams of FIGS. Throughout the drawings, the same reference numerals denote the same objects.

In the first embodiment of the present invention, as shown in the block diagram of FIG. 1 (a), the co-current / wet abatement device 1 is, for example, a mixing scrubber in which a static mixer and a spray are combined. Then, the cleaning liquid 5 is supplied from the cleaning liquid recovery tank 2 to the spray by the cleaning liquid circulation pump 3, and an amount corresponding to the new cleaning liquid supplied from the cleaning liquid supply port 22 is blown.

The countercurrent / wet detector 20 has, for example, a hole diameter of 1φ.
Using a perforated plate scrubber that stabilizes the water surface height on the perforated plate with a perforated plate of ~ 2φ and a downcomer that drops the cleaning liquid 5 from the upper stage to the lower perforated plate,
After using the new cleaning liquid to be replenished in one pass, it is recovered in the cleaning liquid recovery tank 2 and becomes the replenishing cleaning liquid for the co-current / wet abatement system 1. As a result, when high-concentration harmful exhaust gas containing scale components is subjected to primary treatment with the co-current / wet abatement device 1, the cleaning liquid 5 increases the spray amount even if it contains low-concentration harmful components. Since a large gas-liquid ratio can be obtained, the scale components can be prevented from adhering and the removal rate can be increased. In addition, the scale component can be stably maintained below the required concentration by blowing.

On the other hand, the countercurrent / wet abatement device 20 is a secondary treatment, and treats the low-concentration harmful exhaust gas from which scale components have been removed. Let In addition, since the new replenisher can always be used for cleaning, a high degree of removal treatment can be achieved.

Moreover, the scale blockage at the weak point of the co-current / wet abatement device 1 can be eliminated. In addition, since the new replenisher can always be used for cleaning, a high degree of removal treatment can be achieved. Besides, parallel flow
In the wet type detoxifier 1, a mist removing mechanism such as the demister 21 is required in the upper flow, which hinders compactness.

Therefore, this embodiment is an exhaust gas abatement system capable of performing two-step treatment in the same space as the conventional co-current / wet abatement device 1, and can be made compact, and in the case of immediate treatment, an indoor installation space is effective. It can be used. Preventing scale blockage also improves maintainability and contributes to stable and continuous operation of semiconductor manufacturing plants. Moreover, efficient use of the cleaning liquid 5 can be achieved.

The second embodiment of the present invention has a systematic structure in which a heating section 23 is added to the latter stage of the first embodiment, as shown in the block diagram of FIG. 1 (b). By controlling the temperature of the new cleaning liquid supplied from the cleaning liquid replenishment port 22 to promote the mist formation by lowering the dew point temperature of the exhaust gas and improving the removal efficiency of the demister 21, for example, the heat of the exhaust heat By heating in the heating section 23 consisting of an exchanger, the relative humidity can be reduced, the dew condensation on the duct can be prevented, and the white smoke in the discharged exhaust gas can be prevented.

The third embodiment of the present invention has an exhaust fan 24 at the treated exhaust outlet side of the countercurrent / wet abatement machine 20 as shown in the block diagram of FIG. From the ducts after the 24th outlet, a bypass is provided between the co-current / wet abatement device 1 and the counter-current / wet abatement device 20, and the semiconductor manufacturing equipment 10 that discharges the required exhaust gas and the co-current / wet abatement device are installed. A static pressure detector 11 is provided between the harm devices 1 to keep the air volume of the exhaust fan 24 and the treated air amount of the countercurrent / wet harm device 20 constant regardless of changes in the air flow of the co-current / wet harm device 1. Therefore, the removal efficiency of the countercurrent / wet removal device 20 can be kept constant.

The primary treatment enhances the substantial efficiency of the co-current / wet abatement machine 1 without diluting the high-concentration exhaust gas, and is the weak point of the countercurrent / wet abatement machine 20 of the secondary treatment. It is possible to eliminate fluctuations and achieve stable detoxification treatment. Further, the static pressure can be kept stable even if the air volume of the semiconductor manufacturing equipment 10 that discharges the exhaust gas to be processed changes.

In the fourth embodiment of the present invention, as shown in the block diagram of FIG. 2 (d), water is used as the replenisher 6 for the exhaust gas removal system to wash the co-current / wet abatement machine 1. A concentration device 4 is provided on the discharge side of the supply pump 3 to blow the concentrated liquid 7,
By supplying the regenerating liquid 8 as the cleaning liquid 5 for the co-current / wet detoxification device 1, the detoxification ability of the co-current / wet excluding device 1 in the primary treatment is always stabilized. As the concentrating device 4, for example, a reverse osmosis device or an ion dialysis device can be used.

In the fifth embodiment of the present invention, as shown in the configuration diagram of FIG. 2 (e), an intermediate of the cocurrent / wet abatement device 1 and the countercurrent / wet abatement device 20 of the exhaust gas exclusion system is provided. A duct which is provided with a bypass 25 and is connected to the bypass duct 25 from the exhaust inlet of the co-current / wet abatement system 1 via the damper 12,
A damper 28 for partitioning the countercurrent / wet detoxifier 20 from 25 through the damper 27 is provided, and harmful exhaust gas is at least the cocurrent / wet detoxifier 1 or the countercurrent / wet detoxifier 20. And then release it. As described above, in order to maintain continuous operation of the semiconductor manufacturing process, at least a part of the co-current / wet abatement device 1 and the countercurrent / wet abatement device should be used in case of stopping a part of the exhaust gas abatement system immediately after treatment due to an emergency. It is demanded that any one of the harm devices 20 be operated normally and be treated to a value lower than the regulated value of the exhaust gas concentration, and the fifth method of the present invention makes it possible to maintain stable operation.

[0032]

As described above, according to the present invention,
In order to circulate a large amount of cleaning liquid with a parallel flow / wet abatement device for harmful exhaust gas to perform a primary treatment of high-concentration harmful exhaust gas, and to perform advanced treatment with a countercurrent / wet abatement device with a small gas-liquid ratio in the subsequent stage. Therefore, the new cleaning liquid is constantly replenished to remove the harm, and the cleaning liquid is collected in the cleaning liquid recovery tank and used as the cleaning liquid for the co-current / wet detoxifier in the previous stage to improve the cleaning liquid efficiency, improve the treatment exhaust gas treatment, In addition, it can be made compact and maintenance-free during continuous operation.

Further, the addition of the heating section makes it possible to improve the detoxification property and remove white smoke, and the perforated plate type scrubber is adopted for the countercurrent / wet type excluding device to stabilize the fluctuation of the air volume. Also, by adding a concentrating device, the detoxification capacity can be enhanced and stable operation can be maintained during continuous operation.

[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 an explanatory diagram of a conventional example.

[Explanation of symbols]

 1 Parallel flow / wet detoxifier 2 Cleaning liquid recovery tank 3 Cleaning liquid circulation pump 4 Concentrator 5 Cleaning liquid 6 Makeup liquid 7 Concentrate 8 Regenerating liquid 10 Semiconductor manufacturing facility that discharges exhaust gas that needs to be processed 11 Static pressure detector 12 Damper 20 Countercurrent・ Wet abatement device 21 Demister 22 Cleaning liquid supply port 23 Heating part 24 Exhaust fan 25 Bypass duct 26 Air flow controller 27 Damper 28 Damper

Claims (5)

[Claims] 1. An exhaust system in which a co-current / wet abatement device (1) for removing harmful components contained in the exhaust gas is arranged in a front stage and a countercurrent / wet abatement device (20) is arranged in a rear stage, and the exhaust gas is arranged in series. A decontamination system, a cleaning liquid replenishment port (22) for replenishing the cleaning liquid (5) to the upper part of the countercurrent / wet abatement device (20), and the countercurrent / wet abatement device (20). A cleaning liquid recovery tank (2) for recovering the cleaning liquid (5) is provided at the bottom, and the cleaning liquid circulation pump (3) is used to transfer the cleaning liquid (5) from the cleaning liquid recovery tank (2) to a co-current / wet detoxifier ( An exhaust gas abatement system characterized by having a function of circulatingly supplying to (1). 2. The heating unit (23) is provided on the treated exhaust outlet side of the countercurrent / wet abatement device (20).
Exhaust gas abatement system described. 3. The countercurrent / wet detoxification device (20) has an exhaust fan (24) on the treated exhaust outlet side, and the co-current / wet is introduced from a duct after the outlet of the exhaust fan (24). A bypass is provided between the abatement device (1) and the countercurrent / wet abatement device (20), and the air flow rate is adjusted by the signal from the static pressure detector (11) to variably return the circulating exhaust gas of the bypass. The exhaust gas abatement system according to any one of claims 1 and 2, further comprising a device (26). 4. The cleaning liquid (5) for the exhaust exclusion system.
Water is used for the condensate (7) with a concentrating device (4) on the discharge side of the cleaning liquid circulation pump (3) of the co-current / wet abatement system (1).
4. The exhaust gas abatement system according to claim 1, wherein the regeneration liquid (8) is blown to supply the regeneration liquid (8) as the cleaning liquid (5) of the co-current / wet abatement device (1). 5. A bypass is provided between the co-current / wet detoxification device (1) and the countercurrent / wet detoxification device (20).
A bypass duct (25) connected from the exhaust inlet side of the wet type abatement device (1) to the bypass via a damper (12), and the countercurrent / wet type removal from the bypass duct (25) via a damper (27). A duct connected to the exhaust outlet of the damage device (20) and a damper for partitioning the co-current / wet abatement device (1) and the countercurrent / wet exclusion device (20)
The exhaust gas abatement system according to any one of claims 1 to 4, further comprising (28).