JP3306521B2 - Exhaust gas purification method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for purifying exhaust gas, and more particularly to a method and a device for purifying exhaust gas containing acid mist discharged from a semiconductor manufacturing plant or the like.

[0002]

2. Description of the Related Art Exhaust gas containing harmful components discharged from a semiconductor manufacturing plant or the like is discharged after a predetermined purification treatment. In the case of an exhaust gas containing an acid mist, the exhaust gas is brought into contact with water. The acid mist is dissolved in water to separate it from exhaust gas. Normally, as the treated water used for removing the acid mist, general industrial water or the like is used, and the treated water obtained by dissolving and collecting the acid mist as a hydrate is sent to a wastewater treatment facility. After being detoxified,
Recycled or discharged.

[0003]

As described above, in order to remove acid mist in exhaust gas by contact with water and to completely purify exhaust gas while preventing re-scattering of the acid mist, It is desirable to treat with a large amount of water. There is a problem of doing.

In order to reduce the amount of water used, there is a method of adjusting the pH of treated water to be brought into contact with exhaust gas.
Since the exhaust gas purification device becomes complicated, for example, a mechanism for adjusting H must be added, equipment costs, operation costs,
An increase in maintenance costs is inevitable.

On the other hand, in a semiconductor manufacturing plant or the like, since there are many steps using pure water, a pure water producing apparatus is usually installed. This pure water production apparatus removes impurities in water by using ion exchange, reverse osmosis, or the like. However, wastewater in which impurities are concentrated by reverse osmosis or the like is usually discharged as it is.

Accordingly, the present invention can reduce the amount of water used in the above-mentioned exhaust gas purifying facility without complicating the structure of the apparatus, and can effectively utilize the wastewater from the pure water producing apparatus which has been conventionally discharged as it is. It is an object of the present invention to provide a method and an apparatus for purifying exhaust gas.

[0007]

In order to achieve the above-mentioned object, a method for purifying exhaust gas according to the present invention provides a method for purifying exhaust gas containing acid mist.
The gas is converted to various metals such as silica and iron from pure water production equipment.
Counter-current contact with wastewater containing ions, acid mist and metal
A hydrate is formed by a reaction bond with on and the hydrate is removed.
It is characterized by purifying wastewater by removing.

Further, the exhaust gas purifying apparatus of the present invention can be used in underwater.
Impurities and remove pure water and various metals such as silica and iron.
Pure water production equipment that separates wastewater containing ON and acid mist
The acid mist by contacting the exhaust gas containing
A washing tower for removal treatment, and the wastewater is discharged from a pure water production apparatus.
A treated water supply system for supplying treated water to the washing tower was established.
Reaction between acid mist and metal ions by the countercurrent contact
Hydrate formed by coupling removed are characterized and this <br/> to purify waste water.

[0009]

[Operation] The waste water discharged from the above-mentioned pure water production equipment is hard water and contains a large amount of various metal ions such as silica and iron. The acid mist therein quickly reacts with various ions contained in a large amount in the wastewater to form a hydrate and is collected in the water. Therefore, the removal efficiency of acid mist is improved as compared with ordinary water, the amount of water used can be reduced, and the collected acid mist is fixed as a hydrate, so that the acid mist hardly re-scatters.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the drawings. FIG. 1 shows an embodiment of an exhaust gas purifying apparatus according to the present invention. The exhaust gas purifying apparatus includes a washing tower 1 for purifying exhaust gas by contacting it with treated water, and a pure water producing apparatus 2 for producing pure water. The wastewater discharged from the reverse osmosis membrane device of the pure water producing apparatus 2 is supplied as the treated water of the washing tower 1.

The washing tower 1 introduces an exhaust gas containing an acid mist from an exhaust gas inlet 3 provided at a lower portion thereof, and introduces treated water from an upper treated water inlet 4 through a spray nozzle 5 so as to form an exhaust gas. And the treated water are brought into countercurrent contact with each other at the central packed bed 6 to collect acid mist and the like in the exhaust gas in the treated water, thereby purifying the exhaust gas.

A mist collector 8 is provided below the purified gas exhaust port 7 of the washing tower 1, and a treated water tank 9 is provided at the bottom. This treated water tank 9
A water pipe 11 having a pump 10 for sending treated water to the treated water inlet 4, a water receiving pipe 12 for receiving drainage from the pure water producing apparatus 2, and a part of the treated water not shown. A drain pipe 13 for sending to a waste water treatment facility in the process is provided. Further, a damper 14 for adjusting the amount of introduced exhaust gas is provided at the exhaust gas inlet 3.

On the other hand, a drainage tank 15, a pump 16 and the water receiving pipe 1 are provided between the pure water producing apparatus 2 and the washing tower 1.
A wastewater from the pure water production system 2 is provided as a treated water for purifying exhaust gas in the washing tower 1 through the treated water supply system 17 at the bottom of the washing tower 1. It is supplied to the treated water tank 9.

The exhaust gas purifying apparatus is constituted as described above, and the water discharged when the pure water is produced by treating the raw water in the pure water producing apparatus 2 is treated in the washing tower 1 for removing acid mist in the exhaust gas. By using it as water, the acid mist in the exhaust gas quickly reacts and bonds with a large amount of various ions contained in the treated water to form a hydrate, and is fixed in the treated water. Exhaust gas can be purified with almost no re-scattering of acid mist while being removed.

In other words, the washing tower 1 can be effectively used by effectively using the waste water from the pure water producing apparatus 2 which has been discharged as it is.
Not only can clean exhaust gas be discharged from the system, but also the amount of treated water can be reduced, so that the washing tower 1 and the wastewater treatment equipment can be reduced in size and simplified, and the equipment costs and operating costs of the entire exhaust gas purification device Can be greatly reduced.

For example, the concentration of metal ions in the waste water from a general pure water producing apparatus 2 is about twice that of ordinary water. Therefore, the treatment capacity of the acid mist of this wastewater is about twice as large as that of ordinary water. That is, when the amount of circulating water by the pump 10 is constant, the drainage from the pure water producing apparatus 2 has about twice the capacity of holding acid mist. Accordingly, the amount of wastewater discharged from the washing tower 1 to the wastewater treatment facility can be reduced to about half, and the wastewater treatment facility can be reduced in size accordingly.

In the present invention, the construction of the washing tower and the pure water producing apparatus is optional. If the amount of exhaust gas is large and the amount of treated water is insufficient, it may be mixed with ordinary water. It can be carried out with an appropriate device configuration.

[0018]

As described above, according to the present invention, since the waste water from the pure water producing apparatus is brought into contact with the exhaust gas containing the acid mist, the pure water producing method in which the metal ion concentration is about twice that of ordinary water is used. The acid mist can be efficiently removed by effectively using the wastewater from the device , and the acid mist in the exhaust gas can be removed at low cost without increasing the size and complexity of the exhaust gas purifying device.

[Brief description of the drawings]

FIG. 1 is a system diagram showing one embodiment of an apparatus configuration of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rinse tower, 2 ... Pure water production apparatus, 3 ... Exhaust gas inlet, 4
... treated water inlet, 9 ... treated water tank, 17 ... treated water supply system

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Claims (2)

(57) [Claims] An exhaust gas containing an acid mist is supplied to a pure water production apparatus.
From wastewater containing various metal ions such as silica and iron
Flow contact to form a reaction bond between the acid mist and metal ions.
To form a hydrate and remove the hydrate to drain water.
A method for purifying exhaust gas, comprising purifying wastewater. 2. The method according to claim 2 , wherein impurities in the water are removed to remove pure water and silica.
Made of pure water that separates into wastewater containing various metal ions such as iron
Equipment and exhaust gas containing acid mist are brought into countercurrent contact with treated water.
A washing tower for removing the acid mist and treating the wastewater.
A process for supplying treated water from the pure water production device to the washing tower
A water supply system, and an acid mist by the countercurrent contact.
Removes hydrates formed by reaction bonding with metal ions
An exhaust gas purifying device characterized by purifying wastewater by heating .