JPH044811Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a gas-liquid contact type waste gas treatment device.
By sequentially replenishing the processing liquid from the cartridge-type processing liquid tank and maintaining the liquid concentration in the processing tank at a constant level, the equipment can be operated continuously to improve processing efficiency and the entire equipment can be made compact. provide something.

<Prior art> The basic structure of the gas-liquid contact type waste gas treatment equipment that is the subject of the present invention is that a treatment tank houses a treatment liquid, a gas introduction line is connected to the inlet of the treatment tank, and a gas introduction line is connected to the outlet of the treatment tank. The exhaust lines are connected to each other, and the waste gas introduced from the gas introduction line is brought into contact with the treatment liquid in the treatment tank, and the concentration of the target gas in the waste gas is reduced and then discharged from the gas exhaust line. It is something.

As a conventional technique of this type, for example,
As shown in Publication No. 60-175522, the waste gas introduced into the processing tank from the gas introduction line is brought into gas-liquid contact with the processing liquid by bubbling, and then circulated by a circulation pump to the processing liquid showered from above. There are some that remove harm by bringing them into contact again.

<Problems to be solved by the invention> In order to efficiently achieve gas-liquid contact by circulating the processing liquid in the processing tank, the above conventional technology generally increases the volume of the processing liquid and increases its concentration. Therefore, once the treatment liquid is stored in the treatment tank, it is attempted to fully utilize the treatment liquid to perform waste gas treatment over a long period of time.

Therefore, the processing tank has to be large in size because it must accommodate a large amount of processing liquid, and as a result, it takes a long time to replace the processing liquid, and maintenance of the processing apparatus becomes complicated.

In particular, wet processing of SiH ₄ requires a larger volume of processing solution due to reactivity, and
For highly toxic substances such as AsH ₃ , it is necessary to increase the capacity and ensure safety in order to reliably eliminate harm at lower concentrations, and the above-mentioned tendency becomes even more pronounced.

Moreover, in the above-mentioned conventional technology, when replacing the treatment liquid due to a decrease in treatment capacity, the treatment liquid itself that performs detoxification is removed from the treatment tank, so the waste gas is not transferred to the treatment tank. The introduction must be stopped, and in the case of a large volume of treatment liquid as described above, this replacement work cannot be completed in a short time, so the stoppage time becomes long, and the efficiency of the abatement treatment decreases.

Furthermore, the same problem as above occurs when the gas to be removed is changed due to circumstances in the previous process and the processing liquid is replaced.

Furthermore, the installation location of the processing equipment is often in a dangerous area where the atmosphere is such that flames and the like cannot be used. In such areas, when repairing equipment using fire, etc., it is necessary to take special explosion-proof measures. However, even with such curing, the use of fire, etc. is restricted, so quick repairs cannot be made, which lengthens the downtime of the equipment and increases repair costs.

Therefore, in order to shorten or eliminate the above downtime, we installed a spare device in addition to the main device near the main device from the beginning, installed a switching valve in the gas introduction/discharge line, and connected it to the main device. It is also possible to alternately operate the processing devices by switching.

However, in this case, a space is naturally required for installing the preliminary equipment, and the gas introduction/exhaust lines for switching must also be piped in parallel, making the equipment complicated. As a result, equipment costs also become expensive.

This invention improves the efficiency of abatement treatment by eliminating or shortening treatment downtime, and also makes the entire treatment equipment compact, making equipment repairs easy and inexpensive. The technical challenge is to see what can be done.

<Means for solving the problems> Means for achieving the above problems will be described below using drawings corresponding to embodiments.

That is, the present invention has a processing tank 1, a processing liquid tank 2, a drain tank 3, and an on-off valve 1 in the casing 6.
2, a liquid supply device 14 and a sensor 18 for detecting concentration are arranged, and a casing 6, a processing liquid tank 2,
and drainage tank 3 are movable and portable, the processing liquid tank 2 is connected to the processing tank 1 through an on-off valve 12 and a liquid supply device 14 for easy replacement, and a sensor 18 detects the concentration of the processing liquid. is linked to the liquid supply device 14, and the drain tank 3 is connected to the processing tank 1 for easy replacement.If the processing liquid falls below the set concentration, the sensor 18 detects this and drains the liquid from the processing liquid tank 2. The processing liquid is replenished into the processing tank 1, and when the processing liquid rises above a specified liquid level, a part of the processing liquid flows out from the processing tank 1 to the drain tank 3. be.

The processing liquid tank 2 and the drain liquid tank 3 are of a so-called cartridge type that can be easily connected to the processing tank 1 for replacement, and the processing tank 1 is supplied with processing liquid from the processing liquid tank 2 at any time. Also, since the processing liquid can be discharged into the drain tank 3 at any time,
Its capacity can be reduced.

The concentration of the processing liquid to be measured is the concentration of the specified chemical,
Refers to the PH etc. of a solution.

Therefore, the sensor 18 refers to a PH meter that measures the PH of the processing liquid, a spectrophotometer that measures the concentration of a predetermined chemical, a polarograph, various chromatographs, and the like.

The outflow operation from the treatment tank 1 to the drainage tank 3 can be performed manually by controlling the specified liquid level, or a level sensor built into the treatment tank 1 can be used to drain the liquid from the treatment tank 1. This may be done automatically in conjunction with an on-off valve installed up to the liquid tank 3.

In addition, the target gases contained in waste gas are sulfur oxides, which are widely emitted from iron and ceramic industries, etc.
It includes all gases emitted from industry and subject to legal regulations, including nitrogen oxides, halogen gases, silane, arsine, phosphine, etc. emitted during the semiconductor production process.

<Function> When the concentration of the treatment liquid falls below the set concentration due to waste gas abatement treatment, the sensor 18 sends a message to the liquid supply machine 14.
An instruction is issued, and the processing liquid is replenished into the processing tank 1 by the liquid supply device 14 until the specified concentration is reached.

When the liquid level in the processing tank 1 rises above the specified level due to replenishment of the processing liquid, a portion of the processing liquid is removed to the drain tank 3 to restore the liquid level to the specified level.

As a result, the treatment liquid is maintained at a concentration and liquid level suitable for abatement, and the waste gas is smoothly treated.

In addition, the processing liquid in the processing liquid tank 2 runs out,
Alternatively, if the drain tank 3 becomes full of processing liquid, the opening/closing door 7 is opened and the tanks 2 and 3 are replaced with new ones, but the processing liquid in the processing tank 1 does not reach the proper concentration. Because it remains retained and contained, abatement treatment continues even when the tank is replaced. In addition, the processing liquid tank 2 and drainage tank 3 can be moved and
Since it is portable and easy to replace, it can be quickly replaced with new tanks 2 and 3.

<Effects of the invention> (1) Even when the treatment liquid tank and waste liquid tank are replaced, the treatment liquid maintained at an appropriate concentration is stored in the treatment tank, so waste gas abatement treatment is performed. Since the process can be performed continuously without stopping, waste gas can be continuously processed over a long period of time, and the removal efficiency of the processing device can be improved.

The processing liquid is replenished from the processing liquid tank to the processing tank at any time, and is also discharged from the processing tank to the drainage tank at any time. Therefore, if the processing liquid in the processing liquid tank runs out or the drainage tank becomes full, the processing liquid tank and drainage tank should be moved and removed.
Akara is portable and easy to replace, so it can be quickly replaced with a new tank, and it is easy to replenish the treatment liquid to the treatment tank and discharge the treatment liquid from the treatment tank without any problems. Even if a change is made, it can be quickly dealt with simply by discharging the processing liquid in the processing tank into a drainage tank and replacing the processing liquid tank and drainage tank, and the above-mentioned abatement process can be made more efficient.

Furthermore, since the concentration and liquid level in the treatment tank can be maintained constant, the gas-liquid contact reaction between the waste gas and the treatment liquid can be carried out under appropriate conditions.

(2) This processing equipment has a simple structure in which a cartridge-type processing liquid tank and a waste liquid tank are connected to the processing tank, and the processing tank can receive processing liquid from the processing liquid tank at any time. Since the processing liquid in the tank can be discharged to the drain tank at any time, the capacity of the processing tank can be reduced.

Therefore, compared to the conventional gas-liquid contact type, this treatment device does not require a large-capacity treatment tank, and also has a spare treatment liquid tank, drainage tank, and Since there is no need to install piping, switching valves, etc. that communicate with these and the treatment tank, or the pretreatment device itself, the equipment cost can be reduced and the entire device can be made compact with less installation space.

(3) When repairing, the entire casing can be moved and transported, so even if the treatment equipment is installed in a dangerous area where fire cannot be used, the treatment equipment can be moved to a safe area where fire can be used. Since the equipment can be easily moved and there is no need for special protection such as explosion-proofing, the equipment can be repaired quickly and at low cost.

Furthermore, if a movable and transportable spare processing device is brought in and operated in exchange for the main device, processing can be continued without reducing the abatement efficiency.

<Example> Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a schematic longitudinal sectional front view of a gas-liquid contact type waste gas device, and FIG. 2 is a schematic lateral plan view of the same device.
The processing device includes a processing tank 1, a processing liquid tank 2, a drain tank 3, a water replenishment tank 4, and a blower 5 built into a casing 6.

A treatment tank 1 is fixed to the center of the casing 6, and a water supply tank 4 is fixed to the upper right side thereof.

Both the processing liquid tank 2 and the drain liquid tank 3 are cartridge-type box-shaped SUS containers,
Casters 2a and 3a are attached to the bottom,
Each can be easily taken in and out through an opening/closing door 7 provided at the lower front side of the casing 6.

The entire casing 6 is also portable with casters 6a attached to the bottom.

The treatment tank 1 is a cylindrical reactor, and a waste gas introduction line 8 is connected to an inlet 1a opened on the upper left side.
However, a gas derivation line 10 is connected via a blower 5 to an outlet 1b formed in the upper wall thereof.

The processing liquid tank 2 includes a processing liquid supply line 11
is connected to the treatment tank 1 by the supply line 11
The upper end 11a is inserted into the upper space of the processing tank 1 so that the processing liquid flows down in a shower-like manner, and the lower end is easily attached to and detached from the processing liquid tank 2 via a bayonet joint (not shown). It is connected to the.

An on-off valve 12 and a liquid injection pump 14 serving as a liquid supply device are attached to the processing supply line 11, so that the processing liquid can be supplied from the processing liquid tank 2 to the processing tank 1 in an on/off manner.

A downstream part of the on-off valve 12 of the processing liquid supply line 11 and the bottom of the processing tank 1 are connected by a processing liquid circulation line 15, and an on-off valve 16 and a circulation pump 17 are attached to the circulation line 15. It is configured so that the stored processing liquid can be circulated from above the processing tank 1 via a circulation line 15 and a supply line 11 by means of a shower.

A concentration sensor (for example, a PH meter) 18 for measuring the concentration of the processing liquid is connected to the bottom of the processing tank 1, and this concentration sensor 18 is linked to the injection pump 14 on the processing liquid supply line 11, and the processing liquid is If the concentration falls below a set concentration suitable for abatement treatment, the concentration sensor 18 issues an instruction and the liquid injection pump 14 is switched on.

The water replenishment tank 4 attached to the upper right side of the casing 6 is a plastic container whose water volume can be determined, and is connected to the treatment tank 1 via a water replenishment line 20, and an operating on-off valve 21 is attached to the water replenishment line 20. .

Further, the drain tank 3 is connected to the processing tank 1 via a drain line 22, and the drain line 22 is provided with an operation on-off valve 23.

A level sensor 24 is attached to the liquid storage part of the processing tank 1, and this level sensor 24 is linked to the water replenishment line operation on-off valve 21 and the drainage line operation on-off valve 23, respectively. When the liquid level of the processing liquid rises above the specified level, the operation on-off valve 23 is opened and a part of the processing liquid is discharged into the drain tank 3, and when the liquid level falls below the specified level, the operation on-off valve 23 is opened. 21 is opened to supply water from the water supply tank 4 to the processing tank 1.

Note that the capacity of the drain tank 3 is made larger than that of the processing liquid tank 2 in consideration of a safe amount, but if the same type of containers are used for the processing liquid tank 2 and the drain tank 3, for example, After the process liquid tank 2 has been replaced, it becomes possible to use it as the drain liquid tank 3.

According to the above embodiment, the gas introduction line 8 is open to the internal space of the processing tank 1, but it may be bubbled into the processing liquid.

Hereinafter, the abatement treatment of waste gas using the above-mentioned treatment device will be specifically described.

Now 1000ppm ~ 1% _AsH3 diluted with _N2 gas
Let us take as an example the case where the contained waste gas is detoxified into arsenite using a 20% KMnO ₄ aqueous solution.

(1) The KMnO ₄ aqueous solution contained in the treatment tank 1 is showered down from above the treatment tank 1 by the circulation pump 17.

Therefore, the AsH ₃ -containing waste gas introduced into the treatment tank 1 from the gas introduction line 8 is detoxified by gas-liquid contact using a shower of KMnO ₄ aqueous solution, and then sucked by the blower 5 and sent to the gas discharge line 1 .
0 to the outside of the processing tank 1.

In this case, a concentration of about 5% KMnO ₄ aqueous solution is sufficient to treat waste gas containing 1% or less AsH ₃ , but it is set at 20% in consideration of safety.

Further, the concentration sensor 18 is set to have an appropriate concentration range when the KMnO ₄ concentration is, for example, 18 to 20%.

(2) As a result of continued contact with AsH ₃ , when the concentration of the KMnO ₄ aqueous solution falls below the lower limit of the set concentration, the concentration meter 18 gives an instruction to operate the liquid injection pump 14, and the on-off valve 12 opens. Then, a new KMnO ₄ aqueous solution is replenished from the treatment liquid tank 2 to the treatment tank 1, and the concentration of the aqueous solution is adjusted and maintained within the appropriate concentration range.

(3) The inside of the treatment tank 1 is constantly suctioned by the blower 5, and the generated gas generated in the treatment tank is discharged to the outside of the tank from the gas discharge line 10 together with the waste gas after the abatement treatment.

When the suction of the blower accelerates the vaporization of the KMnO ₄ aqueous solution and the liquid level falls from the specified level,
The level sensor 24 issues an instruction to open the operation valve 21, and the water replenishment tank 4 to the processing tank 1
water is replenished and the liquid level is maintained at an appropriate level.

In this case, since the inside of the processing tank 1 is maintained at a negative pressure by the suction of the blower 5, there is no risk of toxic gas generated inside the tank leaking out of the tank, and air pollution can be reliably prevented.

If the concentration sensor 18 is linked to the operation on-off valve 21 of the water replenishment line, even if the aqueous solution is concentrated beyond the upper limit of the set concentration due to vaporization of the aqueous solution, the sensor 18 will be activated.
The operation opening/closing valve 21 opens upon receiving an instruction from the operator, and water can be supplied from the water supply tank 4 to the processing tank 1 to dilute the aqueous solution to an appropriate concentration.

(4) When the KMnO ₄ aqueous solution is replenished into the processing tank 1 for concentration adjustment and the processing liquid level rises above the specified level, the level sensor 24 detects this and causes the operation on-off valve 23 to open. give instructions for
The processing liquid is discharged from the drain line 22 to the drain tank 3 until it reaches the specified level.

If the pipe diameter of the drain line 22 is made large, gases such as generated gas generated during the abatement process that are about to be drawn into the drain tank 3 together with the treated liquid will be reduced to negative pressure by the suction of the blower 5. It becomes easier to rise toward the maintained treatment tank 1.

(5) When the processing liquid tank 2 becomes empty by replenishing the processing liquid to the processing tank 1, replace the tank as follows.

That is, after opening the on-off valve 12, the tank 2 is separated from the processing liquid supply line 11 by operating the bayonet joint and carried out through the on-off door 7 of the casing 6.

Then, a new cartridge-type processing liquid tank 2 is carried into the casing 6 and connected to the processing liquid supply line 11 again.

During this time, since the KMnO ₄ aqueous solution continues to be stored in the treatment tank 1, the abatement treatment of the AsH ₃ -containing waste gas continues without being stopped.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic vertical sectional front view of a gas-liquid contact type waste gas treatment device, and FIG. 2 is a schematic lateral cross-sectional plan view of the same device. 1...Processing tank, 1a...1 inlet, 1b...1
outlet, 2...processing liquid tank, 3...drainage tank, 4...water supply tank, 5...blower, 8...
...Gas introduction line, 10...Gas discharge line, 1
1... Processing liquid supply line, 12... 11 on/off valve, 14... Liquid supply machine, 18... Processing liquid concentration detection sensor, 20... Water supply line, 21... 2
0 on-off valve, 24...level sensor.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A processing liquid is stored in a processing tank, and a gas introduction line is connected to the inlet of the processing tank, and a gas discharge line is connected to the outlet of the processing tank, and the gas is introduced from the gas introduction line. In a gas-liquid contact type waste gas treatment equipment, the waste gas is brought into contact with a treatment liquid in a treatment tank to reduce the concentration of the target gas in the waste gas and then discharged from the gas discharge line. , a processing liquid tank, a drainage tank, an on-off valve, a liquid supply device, and a sensor for detecting concentration are arranged, and the casing, processing liquid tank, and drainage tank are made movable and portable.
The processing liquid tank is easily connected to the processing tank via an on-off valve and a liquid supply machine, and the sensor that detects the concentration of the processing liquid is linked to the liquid supply machine, making it easy to replace the waste liquid tank to the processing tank. By connecting, when the processing liquid falls below the set concentration, the sensor detects this and replenishes the processing liquid from the processing liquid tank to the processing tank, and when the processing liquid rises above the specified liquid level, it is drained from the processing tank. 1. A gas-liquid contact type waste gas treatment device, characterized in that it is configured so that a part of the treated liquid flows out into a liquid tank. 2 Connect the water replenishment tank to the treatment tank via an on-off valve, attach a blower to the gas discharge line, link the level sensor built into the treatment tank with the water replenishment on-off valve, and connect the water replenishment tank inside the casing. , a blower, and a level sensor are arranged.
The gas-liquid contact type gas treatment device described in 2.