JP4805463B2 - Toxic gas abatement equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a harmful gas removal apparatus for removing and collecting harmful gases discharged from semiconductor manufacturing apparatuses, liquid crystal manufacturing apparatuses, and the like.
[0002]
[Prior art]
Since the gas discharged from the semiconductor manufacturing line or the liquid crystal manufacturing line contains harmful gas at the same time as fine powder such as SiO ₂ and WO ₃ , it cannot be released into the atmosphere as it is. Therefore, conventionally, the following methods are used for abatement.
(1) A so-called wet bubbling system that passes through the opening of the punching plate and refines it,
(2) a so-called filler system that collects dust by inertial collision between the water film formed on the surface of the packing and gas, and diffusion adhesion of fine particles,
(3) Combustion method, heating method or dry process,
[0003]
However, in the methods (1) and (2), the detoxification efficiency is poor, and especially for chlorine, it is necessary to add an alkali. However, use of such a drug is not preferable because it causes problems in terms of safety and environment.
The method (3) has many drawbacks such as requiring a large amount of electric power, piping for combustion gas, and the presence of a fire type.
Also, the dry type has a disadvantage that the running cost is high.
[0004]
In view of the above circumstances, an object of the present invention is to perform safe and efficient detoxification.
[0005]
[Means for Solving the Problems]
The present invention relates to a device for removing harmful substances by mixing toxic gas into water, a liquid tank for storing a processing liquid, a circulation path communicating with the liquid tank, a circulation path disposed in the circulation path, and sucked from an intake pipe. A gas-liquid mixing / stirring device that mixes and stirs the toxic gas with the processing liquid to form fine bubbles, and a pump provided in the circulation path for forcibly circulating the processing liquid. The gas-liquid mixing / stirring device is provided on a cylindrical casing, a vane that causes rotation of the liquid in the cylinder, and a cylindrical inner wall on the downstream side of the vane, and a rod-shaped protrusion of a group of protrusions that finely crush the gas The intake pipe has a mechanism for cleaning deposits on the inner wall of the pipe , and a heater is wound in the vicinity of the cleaning mechanism .
[0007]
The liquid tank according to the present invention has a cylindrical shape, and is provided with a punching plate inside the cylindrical shape, and the punching plate is disposed so as to be in contact with the inside of the cylinder obliquely so as to absorb liquid to the pump in the circulation path. Is arranged so as to be the lower surface of the punching plate in the vicinity of the upper end of the punching plate, and its discharge port is arranged to be the lower surface of the punching plate in the vicinity of the lower end of the punching plate .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present inventor considered that the above-mentioned problems could be solved if the abatement efficiency was increased with water alone and chlorine and ammonia could be eliminated.
Therefore, a circulation path is connected to the liquid tank for storing the processing liquid, a pump and a gas / liquid mixing / stirring device are provided in the circulation path, and a toxic gas is supplied to the gas / liquid mixing / stirring device to mix and remove. The harm efficiency was measured. As a result, the chlorine removal efficiency of the conventional method is around 20%, whereas the present invention has an initial removal capacity of 99.999% or more, and the removal efficiency is dramatically improved compared to the conventional method. I understood. The present invention is based on the above research results.
[0009]
【Example】
A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a flow diagram of one embodiment of the present invention. A treatment liquid, for example, water W is stored in the liquid tank 1. The liquid tank 1 is provided with a circulation path 5 for circulating the liquid W in the liquid tank 1 to the outside. The circulation path 5 includes a pump 3, a pressure gauge PIA-1, a flow meter F-2, and a gas. A liquid mixing / stirring device 4 is interposed. The pump 3 is configured such that the rotation speed can be varied according to the set value of the inverter IV and the flow rate and pressure can be adjusted.
[0010]
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.
Although the electromagnetic valve 10 is interposed in the water supply line 8 and is normally closed, the electromagnetic valve 10 is opened by the pH value in the liquid tank 1 detected by the pH meter 7 so that water is supplied into the liquid tank 1. It is configured.
[0011]
The gas-liquid mixing / stirring device 4 is connected to an intake pipe 13 for taking in exhaust from a semiconductor manufacturing apparatus or a liquid crystal manufacturing apparatus. The intake pipe 13 is provided with a pressure gauge PIA-1, a diaphragm valve 15 for adjusting the intake air amount, a fan 12 for assisting a negative pressure of intake air, and a cleaning mechanism 6.
[0012]
A water supply pipe 16 is connected to the cleaning mechanism 6 so as to branch from the water supply line 8 and supply water via the electromagnetic valve 11.
The liquid tank 1 is provided with an exhaust port 14 for exhausting the detoxified gas that has been mixed and stirred by the gas-liquid mixing / stirring device 4 to reach the liquid tank 1 and connected to the exhaust pipe of the production line. It is configured to be able to.
[0013]
As shown in FIG. 2, the gas-liquid mixing / stirring device 4 includes a cylindrical casing 17, a pair of split ellipsoidal disks 18 and 19, and a projection group 20 disposed on the downstream side. 19, the string side edges 18a, 19a are crossed, and the arc side edges 18b, 19b of the pair of split elliptical disks 18, 19 are in contact with the inner wall of the cylindrical casing 17.
[0014]
As shown in FIG. 3, the gas introduction pipe 21 is connected to the gas-liquid mixing / stirring device 4. Although the liquid W in the liquid tank 1 is sent to the gas-liquid mixing / stirring device 4 by the pump 3, the liquid is caused to spiral by the action of the split elliptical disks 18 and 19 and mixed with the gas from the gas introduction pipe 21. The gas is finely crushed by the action of the projection group 20 and mixed with the liquid W.
[0015]
Figure 4 is a detailed view of the intake pipe 13 on the downstream of the gas discharge Kise' connection mouth 23 from the manufacturing apparatus, the pressure gauge P is provided, the intake pressure has to be monitored. Further downstream, a diaphragm valve 15 is interposed so that the amount of gas flowing into the fan 12 can be adjusted. In the present embodiment, the fan 12 is used, but by flowing the liquid W through the gas-liquid mixing / stirring device 4, a negative pressure is generated in the gas-liquid mixing / stirring device 4, and the gas is sucked only by its action. The fan may not be provided depending on the amount of gas to be processed.
[0016]
A cleaning mechanism 6 is disposed on the downstream side of the fan 12, and water is supplied to the opening 6a by water supply from the water supply pipe 16, and water W flows out from the slit 6b to clean the downstream pipe wall 6c. ing. A heater 24 is wound around the pipe in the vicinity of the cleaning mechanism 6 to keep the upper part of the pipe warm.
[0017]
Next, the operation of this embodiment will be described.
When an activation button (not shown) is turned on, the pump 3 is activated and starts to turn the liquid W in the liquid tank 1 to the circulation path 5, and the flow rate in the circulation path 5 becomes substantially constant.
Thereafter, the fan 12 is started and toxic gas guided from the exhaust pipe of the manufacturing apparatus is sent into the circulation system. The liquid W and the gas G fed into the gas-liquid mixing / stirring device 4 are mixed and stirred by the above-described action, and the gas becomes a fine bubble, for example, a bubble having a diameter of 0.5 to 3.0 μm. It is returned to and is abolished.
[0018]
Due to the above action, the dissolved concentration of the gas in the liquid tank 1 increases with time.
That is, the liquid volume in the liquid tank 1 is set to 100 liters, and when chlorine is treated at a rate of 200 cc / min, the pH value becomes 4 or less after about 20 minutes and the detoxification efficiency gradually decreases. End up. Therefore, the pH value in the liquid tank 1 is monitored by the pH meter 7, and the electromagnetic valve 10 interposed in the water supply line 8 is turned on while watching the flow meter F-1 so as to maintain the preset pH value.・ Off and water supply control.
[0019]
When water supply is started, the amount of liquid in the liquid tank 1 increases, and the liquid exceeding 100 liters is discharged from the overflow pipe 9. With this action of the water supply / drainage mechanism, a certain detoxification efficiency can be maintained over time.
[0020]
In this embodiment, the water supply / drainage is controlled by the pH value. However, when the amount of gas to be processed is known in advance, the liquid may be replaced by setting a timer.
Further, the water supply / drainage mechanism is not limited to the one disclosed here, and a drain pipe 39 is provided below the liquid tank 1 via the electromagnetic valve 31, and the liquid is supplied after draining under the control of the liquid level sensor L. May be performed.
[0021]
In the present embodiment, the gas can be stably removed even when time elapses due to the above action, and the removed gas is exhausted from the exhaust port 14 provided in the upper part of the liquid tank 1. Therefore, the gas can be removed with high efficiency if it is a water-soluble gas.
Furthermore, this embodiment is useful not only for gases but also for powders that are often problematic in semiconductor production lines and liquid crystal production lines.
[0022]
The gas discharged from the manufacturing apparatus may contain fine powder, and the powder may cause clogging of piping.
Since the powder tends to adhere to the cooled part, in this embodiment, the water is periodically flowed from the water supply pipe 16 together with the heat insulation of the pipe, and the powder adhering to the pipe wall is washed away by the high humidity, and the gas-liquid mixing is performed. -It feeds into the stirring device 4, traps the powder by the stirring action, and has an action of minimizing the powder flowing into the exhaust port.
[0023]
A second embodiment of the present invention will be described with reference to FIG. The difference between this embodiment and the first embodiment is that a spiral guide vane 18A is provided as a swirl flow generating means instead of providing a pair of conical disks in the gas-liquid mixing / stirring device 4. .
[0024]
A third embodiment of the present invention will be described with reference to FIG. The difference between this embodiment and the first embodiment is that the punching plate 22 is disposed in the cylindrical liquid tank 1.
The peripheral wall 1a of the liquid tank 1 is formed in a cylindrical shape, in which an elliptical punching plate 22 is disposed so as to be inclined in the vertical direction.
[0025]
The punching plate 22 is provided with a plurality of openings 22 a that allow the lower surface and the upper surface to communicate with each other, and the outer peripheral edge thereof is disposed obliquely so as to contact the inner surface of the liquid tank 1. The diameter of the opening 22a is the same as the diameter of the fine bubbles, for example, 2 mm in diameter. The liquid introduction port 5a to the pump 3 is disposed near the upper end 22b of the punching plate 22 so as to be on the lower surface side of the punching plate 22, and the discharge port 5b is disposed on the lower surface of the punching plate 22 near the lower end 22c. It is arranged to be on the side. Since the discharge port 5b is provided in a tangential direction with respect to the peripheral wall 1a, the processing liquid discharged from the discharge port 5b turns along the peripheral wall 1a.
[0026]
When the punching plate 22 is provided in this way, bubbles that have not been sufficiently miniaturized do not rise through the opening 22a of the punching plate 22 and rise along the punching plate 22, and again from the inlet 5a to the pump 3. It will be sucked into the circulation path 5 and miniaturized.
According to the experiment, if the gas amount is approximately 30% of the liquid flow rate in the circulation path 5, it is sufficiently refined by the action of the gas-liquid mixing / stirring device 4, so that the punching plate 22 is installed depending on the gas processing amount. There is no need to do.
[0027]
By making the liquid tank 1 cylindrical, fine gas bubbles rise while rotating in a spiral in the liquid tank 1 and thus stay in the liquid tank 1 for a long time, thus increasing the dissolution efficiency. be able to.
[0028]
【The invention's effect】
Since the present invention is configured as described above, the toxic gas is mixed and stirred with water to form fine bubbles, so that it can be safely and efficiently removed.
Moreover, since the use limit of the process liquid in a liquid tank can be monitored and the performance of a process liquid can be adjusted, it can remove efficiently.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a first embodiment of the present invention.
FIG. 2 is a perspective view of a gas-liquid mixing / stirring device.
FIG. 3 is a longitudinal sectional view of a gas-liquid mixing / stirring device.
FIG. 4 is a longitudinal sectional view of an intake pipe.
FIG. 5 is a longitudinal sectional view showing a second embodiment of the present invention and corresponding to FIG. 3;
FIG. 6 is a longitudinal sectional view showing a third embodiment of the present invention and a perspective view of a liquid tank.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Liquid tank 1 Pump 4 Gas-liquid mixing and stirring apparatus 5 Circulation path 12 Intake pipe

Claims (2)

In a device that removes poisonous gas by mixing it with water,
A liquid tank for storing the processing liquid, a circulation path communicating with the liquid tank, and a gas-liquid mixing that is disposed in the circulation path and mixes and stirs the toxic gas sucked from the intake pipe with the processing liquid to form fine bubbles. A harmful gas abatement device comprising a stirrer and a pump provided in the circulation path for forcibly circulating the treatment liquid;
The gas-liquid mixing / stirring device includes a cylindrical casing, a vane that causes rotation of the liquid in the cylinder, and a rod-shaped protrusion of a protrusion group that is provided on the cylindrical inner wall on the downstream side of the vane and finely breaks the gas. Prepared,
The intake pipe has a mechanism for cleaning deposits on the inner wall of the pipe,
A harmful gas abatement apparatus, wherein a heater is wound in the vicinity of the cleaning mechanism . The liquid tank has a cylindrical shape, a punching plate is provided inside the cylindrical shape, the punching plate is disposed so as to be in contact with the inside of the cylinder obliquely, and the inlet for sucking liquid into the pump of the circulation path is The punching plate is disposed so as to be a lower surface of the punching plate in the vicinity of the upper end of the punching plate, and the discharge port is disposed so as to be a lower surface of the punching plate in the vicinity of the lower end of the punching plate. The harmful gas removal apparatus according to 1.

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