JP2006263671A - Method for detoxifying hazardous gas and its apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a reduction in detoxifying efficiency and also provide so as not to block a gas-liquid mixture and agitation device. <P>SOLUTION: An apparatus S for detoxifying a hazardous gas comprising a liquid tank 1 storing liquid to be treated W, and the gas-liquid mixture and agitation device 4 communicating with the liquid tank 1 to mix and agitate the liquid to be treated and gas sucked from a suction pipe 13, wherein the suction pipe 13 is provided with shower pretreatment means 25. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a harmful gas removal method and apparatus for removing and collecting harmful gases discharged from semiconductor manufacturing apparatuses, liquid crystal manufacturing apparatuses, and the like.

Gases discharged from semiconductor production lines and liquid crystal production lines contain fine gases such as SiO ₂ and WO _{3 as} well as harmful gases such as HF, BCl ₃ , Cl ₂ and Hcl. Cannot be released inside. Therefore, conventionally, harmful gas is removed using the following apparatus (for example, see Patent Document 1).

  A device for removing harmful gases by mixing them with water, a liquid tank for storing a processing liquid, a circulation path communicating with the liquid tank, a harmful path disposed in the circulation path and sucked from an intake pipe A gas-liquid mixing / stirring device that mixes and stirs gas with the processing liquid to form fine bubbles, and a pump that is provided in the circulation path and forcibly circulates the processing liquid are provided.

Japanese Patent Application No. 2001-018122

The conventional harmful gas removal device has an initial removal capability of 99.999% or more, and the removal efficiency is extremely good. However, if the semiconductor manufacturing apparatus is used for a long time or the inside of the chamber is cleaned with CF ₄ or SF ₆ , the detoxification efficiency may be reduced, or powder or dust may be clogged.

  In view of the above circumstances, an object of the present invention is to prevent a reduction in detoxification efficiency and prevent clogging of powder, dust and the like.

  The present invention includes a liquid tank for storing a processing liquid, and a gas-liquid mixing / stirring device that communicates with the liquid tank and mixes and stirs the processing liquid and the harmful gas sucked from the intake pipe. A detoxification device, characterized in that shower pretreatment means is provided in the intake pipe.

  The shower pretreatment means of the present invention is characterized by spraying water toward harmful gas.

  The present invention supplies a gas-liquid mixing / stirring device with a processing liquid and a harmful gas sucked from an intake pipe, and mixes and stirs it to form a gas-liquid mixed fluid. The gas-liquid mixed fluid is treated in a liquid tank. The harmful gas is a mixed harmful gas composed of a plurality of harmful gases, and the mixed harmful gas is preliminarily removed by a shower pretreatment means before being supplied to the mixer. It is characterized by harm.

Mixed harmful gas of the present invention is characterized in that it contains HF, BCl3, Cl _2.

  Since this invention preliminarily detoxifies the mixed harmful gas with the shower pretreatment means before supplying it to the gas-liquid mixing / stirring device, the gas-liquid mixing / stirring device has a hardly water-soluble harmful gas that is difficult to dissolve in water. Only gas is supplied and gas-liquid mixing is performed. For this reason, a fluid having a property capable of sufficiently exhibiting the detoxifying ability is fed into the treatment liquid of the liquid tank, so that the detoxifying efficiency can be improved. Further, the shower pretreatment means removes powders and dusts contained in the harmful gas, so that clogging of the gas-liquid mixing / stirring device and the like can be prevented.

The present inventor conducted the following experiment using the conventional abatement apparatus in order to investigate the cause of the problem in the conventional example.
Hazardous gas a: Cl ₂ gas 200cc, b: Cl ₂ gas + BCl ₃ gas 200cc
N ₂ gas 30 l / min. In this ratio, only the gas a: and only the gas b: were supplied to the abatement apparatus, and HCl and Cl ₂ at the outlet were measured. As a result, HCl was 15 ppm for both a: and b: , Cl ₂ was 40 ppm for a: and 300 ppm for b :.
As a result of this experiment, when BCl ₃ gas that is easily dissolved in water (decomposable with water) is mixed in harmful gas, the efficiency of removing Cl ₂ is reduced, and the abatement device has the original abatement performance. I found out that I couldn't do it.

The present inventor has found that the problem of the conventional example is that the harmful gas to be treated is more easily dissolved in water than a standard water-soluble harmful gas (for example, a harmful gas such as HF or BCl ₃ ) and water than the standard water-soluble gas. In order to solve this problem, we are convinced that the cause is mixed harmful gas consisting of difficult-to-dissolve poorly water-soluble harmful gases (for example, Cl _{2 and} other harmful gases). It was considered that the gas and the harmful gas that is difficult to dissolve in water should be removed separately, and that the removal means should have a performance corresponding to that.

  As a result of repeated earnest research experiments, the present inventor did not supply harmful gas sucked from the intake pipe directly to the gas-liquid mixing / stirring device, but once supplied it to the shower pretreatment means, and was easily dissolved in water. We learned that gas should be removed (preliminary removal), and then only the poorly water-soluble harmful gas should be supplied to the gas-liquid mixing / stirring device and removed by the removal device. The present invention has been completed based on the above findings.

An embodiment of the present invention will be described with reference to FIG.
In the liquid tank 1 of the abatement apparatus S, a processing liquid, for example, water W is stored. The liquid tank 1 is provided with a circulation path 5 for circulating the processing liquid W in the liquid tank 1 to the outside. The circulation path 5 includes a pump 3, a differential pressure gauge, a flow meter (not shown), and a gas. A liquid mixing / stirring device 4 is interposed. The phone 3 is configured such that the number of revolutions can be changed by the set value of an inverter (not shown), and the flow rate and pressure can be adjusted.

  The liquid tank 1 is provided with an overflow pipe 9 and a water supply line 8 so as to drain the liquid when the liquid amount exceeds a certain amount, for example, 100 liters. An electromagnetic valve (not shown) is interposed in the water supply line 8 and is normally closed, but the electromagnetic valve is opened by the pH value in the liquid tank 1 detected by the pH meter 7 to supply water into the liquid tank 1. It is configured as follows.

  The liquid tank 1 is provided with an exhaust port 14 connected to an exhaust pipe (not shown) of the production line. The exhaust port 14 exhausts the detoxified gas 14 a generated in the liquid tank 1.

  The liquid tank 1 communicates with the gas-liquid mixing / stirring device 4, and this gas-liquid mixing / stirring device 4 communicates with the shower pretreatment means 25 via the connecting pipe 29.

  The gas-liquid mixing / stirring device 4 is composed of a cylindrical case (not shown), a pair of split ellipsoids (not shown), and a group of protrusions (not shown) arranged on the downstream side. The chord side edges are crossed so that the arc side edges of the pair of split ellipsoids are in contact with the inner wall of the cylindrical casing.

  In this gas-liquid mixing / stirring device 4, when the pump 3 is activated and the processing liquid W in the liquid tank 1 is sent into the gas-liquid mixing / stirring device 4, the liquid W is A spiral flow is generated and mixed with the gas from the gas introduction pipe 21, and the gas is finely crushed by the action of the projection group and mixed with the processing liquid W.

  The shower pretreatment means 25 includes a shower room 26. A shower 27 is provided on the ceiling of the shower chamber 26, and a lower portion thereof communicates with a drain tank 28. The drain tank 28 is connected to a drain line 28L having a pump 28P. The pump 28P is driven to drain water 28a from the drain line 28L.

  The shower chamber 26 is connected to the intake pipe 13 and the bypass pipe 24 via a valve 23. The intake pipe 13 sucks harmful gas 13g from the semiconductor manufacturing apparatus or the liquid crystal manufacturing apparatus. The intake pipe 13 is provided with a pressure gauge (not shown), a diaphragm valve (not shown) for adjusting the intake air amount, and a fan (not shown) for assisting the negative pressure of the intake air.

Next, the operation of this embodiment will be described.
When a start button (not shown) is turned on, the pump 3 is started, the processing liquid W in the liquid tank 1 starts to be turned to the circulation path 5, and the flow rate in the circulation path 5 becomes substantially constant.

Thereafter, when the valve 23 of the intake pipe 13 is opened, the fan is activated and the harmful gas guided from the exhaust pipe of the manufacturing apparatus is sent into the shower chamber 26. The toxic gas, HF, BCl3, Cl ₂ is a mixed gas containing, HF, BCl ₃ is easily decomposed standard water-soluble toxic gases with water, also, Cl _2, from the standard water-soluble hazardous gas It is also a poorly water-soluble harmful gas, which is difficult to dissolve in water.

The mixing hazardous gases, impaired pre dividing receives water spray in the shower chamber 26, HF, BCl _3, etc., deposited material, trap or the like is abated. Therefore, the only harmful gas sent from the shower chamber 26 into the gas-liquid mixing / stirring device 4 is Cl ₂ gas (poorly water-soluble harmful gas).

This hardly water-soluble harmful gas is mixed and stirred with the treatment liquid W in the gas-liquid mixing / stirring device 4, and the gas becomes fine bubbles, for example, bubbles having a diameter of 0.5 to 3.0 μm in the liquid tank 1. Returned and detoxified.
In this main detoxification, the detoxifying apparatus S detoxifies the harmful gas (slightly water-soluble noxious gas) originally planned, and therefore can be efficiently detoxified.

It is a block diagram which shows the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid tank 4 Gas-liquid mixing and stirring apparatus 13 Intake pipe 25 Shower pretreatment means 26 Shower room 27 Shower S Detoxifying device

Claims (4)

A harmful gas abatement device comprising: a liquid tank for storing a treatment liquid; and a gas-liquid mixing / stirring device that communicates with the liquid tank and mixes and stirs the treatment liquid and the harmful gas sucked from the intake pipe. There;
A harmful gas abatement apparatus, characterized in that a shower pretreatment means is provided in the intake pipe.   2. The harmful gas removal apparatus according to claim 1, wherein the shower pretreatment means sprays water toward the harmful gas. Supply the processing liquid and the harmful gas sucked from the intake pipe to the gas-liquid mixing / stirring device, mix and stir to make the gas-liquid mixed fluid, and mix the gas-liquid mixed fluid into the processing liquid in the liquid tank. A method of abatement;
The harmful gas is a mixed harmful gas composed of a plurality of harmful gases,
Prior to supplying the mixed harmful gas to the gas-liquid mixing / stirring device, preliminary harmful treatment is performed by shower pretreatment means. 4. The harmful gas removal apparatus according to claim ₃ , wherein the mixed harmful gas contains HF, BCl ₃ , and Cl _2.

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