JP3030282B2 - Air purification system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air cleaning method and an air cleaning apparatus for local cleaning used in a factory for manufacturing electronic components such as a clean room and a local clean tunnel. The present invention relates to an air cleaning system which has low cost and running cost and can always maintain a constant degree of cleaning.

[0002]

BACKGROUND OF THE INVENTION minute in the air, Eawasshi turbocharger as an apparatus for removal of trace impurities - air cleaning system of the system is known (1998 April 16, 17 days held, 16
Times air purification and contamination control competition,
(A-2) Investigation of the actual condition of the inorganic component removal performance of the air washer, (A-3) Removal of atmospheric chemical substances by the air washer (Part 2) Influence of water quality on the removal effect, etc.).

[0003] The air purifying apparatus according to this method is classified into a wet scrubber method generally used for removing high-concentration gas components. The wet scrubber method includes the following apparatuses. .

[0004] Moretana tower: A plurality of perforated plates of weirs and overflow parts are installed in the tower and brought into countercurrent contact with exhaust gas. Packing tower: Absorbing liquid is poured on the surface of a packing material with a large surface area,
The gas is brought into countercurrent contact at a low speed. Spray tower: The absorption stream is sprayed into the empty tower, and the gas is brought into countercurrent contact at a low speed. Cyclone scrubber: The gas is introduced into the absorption tower in a cyclone stream and sprayed in the tower. Venturi scrubber: A gas is caused to flow through a venturi at a high speed and mixed with a small amount of water. Jet scrubber: A gas is flowed through the slot at a slightly higher speed, and mixed together with a large amount of water. Fluidized absorption tower: The plastic spheres filled in the tower form a fluidized bed and come into countercurrent contact with the stream.

[0005] Among the above-mentioned various systems, the spray tower system and the cyclone scrubber system have been put to practical use as air purifiers.

The spray tower system is similar to the air-washer system, and the cyclone scrubber system is
For example, Japanese Patent Publication No. 3-76993, Japanese Patent Publication No. 3-76
994, JP-A-62-685105, JP-A-4-111868, JP-A-10-113525
This is similar to the air purifying device disclosed in Japanese Patent Application Publication No. JP-A-H07-209139.

Further, in an air washer type air purifying apparatus, it has been found that impurities in the air can be effectively removed by using ultrapure water as water used for the air washer. April 16, 2010
(A-2) Investigation of the actual condition of the inorganic component removal performance of the air washer at the 16th Air Purification and Contamination Control Competition held on the 17th and 17th, (A-3) Removal of atmospheric chemical substances by the air washer ( Part 2) Influence of water quality on the removal effect, etc., are known.

[0008]

However, in the above-mentioned conventional air purifying apparatus, the technology for maintaining and controlling the degree of purification of the treated air at a constant level has been hardly studied. You are in an unsatisfied state.

For example, in a method in which impurities in the air are collected in a collecting liquid for several hours using the impinger method and then analyzed by a commercially available water quality analyzer using an ion chromatograph or the like, a result is obtained. It takes more than one or two days before the analysis results indicate that the presence of impurities exceeding the standard in the air is delayed.

[0010] Recently, a clean room gas monitor using a diffusion scrubber method (Yokogawa Electric stock company or Daionikusu Co., Ltd.) are commercially available, and it takes a few tenths of time to be analytical control these gas monitor, Considering the reliability of data, there is a problem that it takes several hours to respond.

Although it is desirable to control the degree of air purification by directly measuring the concentration of the chemical substance in the treated air at the outlet of the air purifying apparatus, it is difficult for the known method to obtain results. There was a problem that it took too much time to respond in time.

The inventors of the present invention have conducted intensive studies to solve the conventional problems, and found that the concentration of the chemical substance in the air processed by the air washer-type air purifying apparatus and the air washer-type air purifying method. It has been found that there is a good correlation between the chemical substance concentration in the injection water used in the apparatus. That is, the chemical substance concentration in the treated air can be known by measuring the chemical substance in the jet water. In this specification,
Of the chemical substance in the jet water is determined by the TOC in the jet water.
It is the concentration of the total evaporation residue including the components.

Therefore, when the air in the enclosed space is circulated through an air washer-type air purifying apparatus to purify the air, the concentration of the chemical substance in the ultrapure water used in the apparatus is continuously measured, and By maintaining the chemical substance in the feed water at a constant concentration based on the measurement result, the same result as directly measuring and managing the treated air can be obtained in a short time.

The present invention has been made based on such knowledge, and provides an air purifying system which has a low facility cost and a running cost and can maintain a constant high degree of cleanliness at all times. With the goal.

[0015]

A first embodiment of the air cleaning system of the present invention is an air-washer type air cleaning system .
A purifier and a buffer for condensed water of the air purifier.
Collected in a tank, and from the buffer tank, the air cleaning device.
Recirculated water supplied to the unit as water injected by air washers
Device and the total evaporation residue of the condensed water supplied as the injection water
And the total evaporation residue渣監vision system for monitoring the residue, the buffer tank
Incorporates condensed water in the oil and reduces the impurity concentration until it becomes ultrapure water
A water purification device to supply the water to the buffer tank again,
Purification of the water quality by the output signal of the total evaporation residue monitoring device
Controls the amount of ultrapure water supplied from the device to the buffer tank
And a control device . Also book
A second embodiment of the air cleaning system of the invention is an air purifier.
A washer-type air cleaning device;
The condensed water in the buffer tank
From the air purifier to the water jet of the air washer
A recirculating water supply device for supplying
Monitoring system for monitoring the total evaporation residue of condensed water
And diluting the condensed water supplied as the injection water with ultrapure water.
Water purification device to reduce impurity concentration
An output signal from the residue generation monitoring device sends the water purification device
A control device for controlling dilution with ultrapure water
It is characterized by.

The air purifying device includes, for example, an air flow path surrounded by a partition, a water injection nozzle disposed in the air flow path, and a plurality of water injection nozzles disposed downstream of the water injection nozzle. A screen, an air supply fan that forms an air flow from the water injection nozzle toward the screen side in the air flow path to form a decompression region on the back side of the screen, and is disposed downstream of the screen. A device having a cooling means for condensing and removing mist in the air flow can be used, but is not necessarily limited to such a device. Any so-called air washer type air cleaning device can be used.

The particle size of the water droplets injected into the air stream from the water injection nozzle is, for example, 10 to 100 μm, and the particle size of the mist split by expansion under reduced pressure is, for example, 0.00.
1 to 0.1 μm.

The water droplets injected into the air stream from the water injection nozzles capture impurities in the air mainly by movement mainly due to inertial motion, and the ultrafine mist split by decompression expansion expands mainly into Brownian movement. Traps impurities in the air.

It is desirable that the flow rate of the air flow be 5 m / sec or more.

The injection amount (l) of the water droplet injected from the water injection nozzle is 0.5 to 0.7 l / l with respect to the air amount (m ³ ).
m ³ is desirable, and the jet pressure of the water droplet is 0.1 m ³ .
Desirably, the pressure is 5 to 1.5 kg / cm ² G.

It is preferable that the condensed water of the air cleaning device is stored in a buffer tank and the recirculated water supply device supplies the condensed water of the air washer of the air cleaning device.

The following is an example of the water purification apparatus used in the present invention.

(A) An ultrapure water supply line for taking out water contained in the buffer tank, removing organic substances, ionic substances and fine solid substances dissolved in the water and returning the same to the buffer tank again.

(B) An ultrapure water supply line for disposing a part of the water in the buffer tank and supplying ultrapure water to the buffer tank.

(C) Inlet pipe and outlet each equipped with a valve
A plurality of sub-buffer tanks having pipes and drain pipes, a first communication pipe connecting the inlet pipes of each sub-buffer tank in parallel and connecting to the outlet pipe of the buffer tank, and an outlet pipe of each sub-buffer tank. A second communication pipe connected in parallel and connected to a water supply pipe of a water spray nozzle of an air washer of the air cleaning device; a circulation pump provided in the first or second communication pipe; A control device for operating a valve, and an ultrapure water for supplying ultrapure water to each of the sub-buffer tanks
An apparatus provided with a water supply pipe .

In addition, a total steam for monitoring all evaporation residues of the condensed water.
Is a Hatsuzan渣監vision equipment Full evaporation residue渣計is used but T
An OC meter can be used together.

It should be noted, by the dissolution of carbon dioxide in the air in d ah washer system, the conductivity of the condensed water, 0.8
Since decreases until 1.0μS / cm ^2, the controlling the chemical substance concentration in air at 0.1 to several [mu] g / m ³
In the invention, the water quality cannot be controlled only by the conductivity meter.

[0028]

The water droplets jetted from the jet nozzle in countercurrent to the air flow become fine mist and capture dust and gaseous chemical substances in the air and take them into the mist by inertial motion at the time of jetting. Most of the coarse water droplets and mist are condensed in the mist trap 4b and flow down into the buffer tank 7 together with the trapped chemical substance, but some mist not trapped in the mist trap 4b and 100% R
The water vapor in the H air is condensed by the eliminator 5 and dehumidified.

At this time, the chemical substance contained in the 100% RH is not condensed in the mist trap 4b and is sent out from the outlet of the air duct 2 together with the dehumidified air.

In a closed system in which both ultrapure water and air are present, the amount of the chemical substance in the ultrapure water and air tends to reach a predetermined distribution ratio according to the conditions such as the liquid-gas ratio and the temperature. I do.

That is, when the concentration of the chemical substance in the sprayed mist is very low in balance compared to the concentration of the chemical substance in the air, the ionic components and the water-soluble organic components are dissolved into the mist by dissolution. Poorly water-soluble organic components try to dissolve to a concentration proportional to the gas partial pressure in the air according to Henry's law.

Thus, the point at which the concentration of the chemical substance in the mist balances the concentration in the air is the final concentration of the chemical substance in the air under the conditions in the closed system.

Therefore, for example, when the concentration of the chemical substance in the air before the air washer treatment is high, the concentration of the chemical substance in the jet water is controlled to be low, and when the concentration of the chemical substance in the air before the air washer treatment is low, the injection is performed. By controlling the concentration of the chemical substance in the water high, the concentration of the chemical substance in the treated air can be controlled to a constant concentration.

In the case of an air-washer type air conditioning system, the concentration of chemical substance impurities in the buffer tank is reflected on the processing capacity of the chemical substance in the air, and this concentration is measured to operate the water purification apparatus. By controlling, the impurity concentration at the outlet of the air duct 2 can be maintained at a certain level or less.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION

[0036]

Embodiment 1 FIG. 1 is a diagram schematically showing an embodiment of an air cleaning system of the present invention.

In the figure, reference numeral 1 denotes an air-washer type air cleaning device.

[0038] This is near the entrance air intake which is connected to, for example, a clean room air duct 2 of the air cleaning apparatus 1 is pre-filter 3 for dust removal is mounted, the Eawa <br/> Tsu sheet catcher -4 downstream Are located. Eawasshi catcher -4 jet nozzle 4a with placing a large number of injection ports toward the upstream side, opposite to the injection port of the injection nozzle 4a is constructed by arranging a mist trap 4b made mist impingement plate I have. Eawasshi catcher -4 with placing the injection nozzle 4a or al multi <br/> number of injection ports toward the upstream side, a mist trap 4b made opposite to mist impingement plate to the injection port of the injection nozzle 4a It is arranged and configured.

[0039] Downstream of Eawasshi catcher -4, 100% R
An eliminator 5 that cools and dehumidifies the H air is installed, and an air supply fan 6 that generates an air flow of 5 m / sec or more in the air duct 2 is installed near the downstream outlet.

Below the air washer 4 and the eliminator 5, a buffer tank 7 for receiving condensed water is provided.

The buffer tank 7 has a buffer tank 7
Ultrapure water supply line 8 for circulating and purifying condensed water inside
And the water supply pipe 9 of the water spray nozzle 4a of the air-washer-4
An injection water supply line 10 for supplying injection water is provided.

The ultrapure water supply line 8 includes a pump 11, a flow control valve 12, a control device 13 for controlling the opening of the flow control valve, an ultraviolet irradiation device 14, an ion exchange resin cylinder 15, a filter 16, and a control device. It is composed of a pipe 17 for connecting these components except for the components.

The injection water supply line 10 is connected to the pump 1
8, the cooler 19 and the water pipe 9
, And a pipe 20 connected thereto.

A sampling pipe 21 for measurement branches off from a pipe 20 between the cooler 19 and the injection nozzle 4a to supply sampled sample water to a measuring device 22.

The measuring device 22 includes an ion chromatograph,
Has a TOC meter and the total evaporation residue meter, the water quality of the water sample, and rapidly measure the chemical substance concentration in particular all evaporation residue渣計, to supply measurement data to the control unit 13 via the signal cable 22a Is configured. The controller 13 is configured to perform control to increase the opening of the flow control valve 12 when the chemical substance concentration is high and to decrease the opening when the chemical substance concentration is low, according to the measurement data. .

Next, the operation of the apparatus of this embodiment will be described.

First, the buffer tank 7 is filled with ultrapure water, and the pumps 11 and 18 are driven to drive the ultrapure water supply line 8.
While operating the water supply line 10 and the injection water supply line 10.
Is driven, an air flow is formed in the air duct 1 and ultrapure water is injected from the injection nozzle 4a. The jetted water droplets are miniaturized by countercurrent to become mist M, and in this state, take in dust and gaseous chemical substances. The mist having a large particle diameter strikes the mist trap 4b and condenses and flows down into the buffer tank 7, where the fine mist and 1
The air that has become 00% RH is carried by the air stream, comes into contact with the eliminator 5, condenses, and flows down into the buffer tank 7.

The gaseous chemical substance in the 100% RH air which is not captured by the mist M is not condensed by the eliminator 5, so that the air duct 2
Is discharged from the outlet.

The concentration of the chemical substance taken by the mist and the concentration of the chemical substance remaining in the air have a substantially constant ratio, and the concentration of the chemical substance discharged from the air duct 2 is correlated with the concentration of the chemical substance in the jet water. From the above, the signal from the measuring device 22 is supplied to the control device 13, and the control device 13 controls the opening degree of the flow control valve 12 so that the measured value is equal to or less than a certain level, and maintains the quality of the supply water at a certain level or more By doing so, the cleanliness of the air at the outlet of the air duct 2 can be maintained at a level higher than a certain standard.

(Experimental Example) An experiment was conducted using the air purifying apparatus shown in FIG. 1 under the following conditions.

[0051] Processing capacity of air purifier ... 50 CMM liquid-gas ratio ... 2 injection water volume・ ・ ・ ・ ・ ・ ・ 6m ³ / h Spray water capacity ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ About 1m ³ Ultrapure water system processing capacity ・ ・ ・ ・ ・ ・ ・ ・ ・ 1m ³ / h Ultrapure water system supply water quality ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Specific resistance 18MΩ ・ cm Chemical substance ≦ 1μg / L (NH ₄ ⁺ , SO ₄ ²⁻ , NO ₃ ⁻ , NO ₂ ⁻ ) When the ultrapure water system is operated with the measuring device 22 and the control device 13 not included in the system, and the ultrapure water system is operated. A comparative experiment was carried out in the case where no test was performed.

The operation of the air purifier was continued for 6 hours, and the concentration of the chemical substance in the air and the concentration of the injection water were measured.

Evaluation of chemical substances in the air was carried out by collecting treated air in ultrapure water for the same time as the operation time by using the impinger method, and analyzing the collected liquid.

The water quality of the injection water was evaluated by analyzing the initial water quality and the water quality after 6 hours. The analytical substance was NH ₄ ^+, and an ion chromatograph was used for the analysis.

Table 1 shows the results.

[0056]

[Table 1] From the results in Table 1, it can be seen that there is a correlation between the water quality and the concentration of the chemical substance in the treated air.

Next, in order to measure the impurity concentration in the air in a short time, an impurity monitoring device in a clean room described in Japanese Patent Application No. 7-310604 (measurement can be performed once every about 20 minutes)
And the control device 13 and the measuring device 22 are operated by using the total evaporation residue meter (continuous measurement is possible) described in Japanese Patent Publication No. 6-39661 to measure the chemical substance in the feed water in a short time. A similar experiment was performed.

Table 2 shows the results.

[0059]

[Table 2] From the results in Tables 1 and 2, there is a strong correlation between the concentration of the chemical substance in the ultrapure water and the concentration of the chemical substance in the processing air, and the control of the concentration of the chemical substance in the processing air by the apparatus of this embodiment. I understand.

[0060]

Embodiment 2 FIG. 2 schematically shows another embodiment of the air cleaning system of the present invention. In the following drawings, portions common to the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

In the air cleaning system of this embodiment, ultrapure water is supplied to the buffer tank 7 from the makeup water supply line 23, and excess water is discharged from the overflow line 24 to enhance the water quality. It is. Therefore, the makeup water supply line 23 of this embodiment is connected to a use point of another ultrapure water production line.

In this embodiment, since the ultrapure water supply line 8 in the first embodiment is omitted, equipment cost and space efficiency are improved.

[0063]

Third Embodiment FIG. 3 is a view schematically showing still another embodiment of the air cleaning system of the present invention.

[0064] In the air cleaning apparatus of this embodiment, the inlet pipe 25 with a valve respectively, the two sub-buffers over tank 29 with an outlet pipe 26 and drain pipe 27
When, a communicating tube 30 connected to the outlet pipe of the buffer over the tank 7 the inlet pipe 25 and connected in parallel in each sub-buffer tanks 28 and 29, connecting the outlet tube 26 of each sub-buffer over tank 28, 29 in parallel A communication pipe 31 connected to a water supply pipe of a water spray nozzle 4 a of an air-washer 4 of the air cleaning device 1; a circulation pump 32 provided in the communication pipes 30, 31;
The valves 33a, 33b, 33c, 34 of the inlet pipe 25, the outlet pipe 26, and the drain pipe 27 are output by the output of the measuring device 22.
a, 34b, and 34c.

In this device, during normal operation, the valve 33
c and 34a, 34b, 34c are closed and valve 3
Only the valves 3a and 33b are open, and when the operation is stopped and the drainage is performed, the valves 33a and 33b are closed and the valves 33a and 33b are closed.
c is opened. In addition, during water supply and standby, the valve 33
a, 33b, and 33c are all closed.

When the water quality deteriorates, the valve 33
The valves 34a and 34b are opened together with the valves 33a and 33b to enhance the water purification ability. Also, the valve 33a,
If there is a failure on the side of 33b, 33c, these valves are closed and only the valves 33a, 33b are opened.

As described above, according to this embodiment, it is possible to cope with various situations by switching the valve.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an embodiment of an air cleaning system of the present invention.

FIG. 2 is a view schematically showing another embodiment of the air cleaning system of the present invention.

FIG. 3 is a view schematically showing still another embodiment of the air cleaning system of the present invention.

[Explanation of symbols]

1 ... air cleaning device, 2 ... air duct, 3 ... pre-filter, 4 ... air washer, 4a ... injection nozzle,
4b: mist trap, 5: eliminator, 6 ...
Air supply fan, 7: Buffer tank, 8: Ultrapure water supply line, 9: Water supply pipe, 10: Injection water supply line, 1
DESCRIPTION OF SYMBOLS 1 ... Pump, 12 ... Flow control valve, 13 ... Control device, 14 ... Ultraviolet irradiation device, 15 ... Ion exchange resin cylinder, 16 ... Filter, 17, 20 ... Piping, 1
8 pump, 19 cooler, 21 sampling pipe for measurement, 22 measuring device, 23 supply water supply line, 24 overflow line, 25 inlet pipes 25, 26 outlet Pipe, 27 ... Drain pipe, 28, 29 ...
… Sub-buffer tank, 30, 31 …… Communication pipe, 32…
... circulation pumps, 33a, 33b, 33c, 34a, 34
b, 34c ... valve.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B01D 53/14-53/18

Claims (5)

(57) [Claims] 1. An air-washer type air cleaning device.
And collecting the condensed water of the air purifying device into a buffer tank.
An air washer from the buffer tank to the air purifier
A recirculating water supply device for supplying water as injection water for the condenser, and monitoring of all evaporation residues of condensed water supplied as the injection water
Total evaporation residue monitoring device that takes up condensed water in the buffer tank until it becomes ultrapure water
Reduce the impurity concentration and supply to the buffer tank again
Water purification by means of a water purification device and an output signal of the total evaporation residue monitoring device.
Controls the amount of ultrapure water supplied from the device to the buffer tank
Air cleaning system; and a that controller. 2. An air-washer-type air cleaning device, and a condensed water of the air cleaning device is collected in a buffer tank and supplied from the buffer tank to the air cleaning device as injection water of an air washer. a circulation water supply unit, and the total evaporation residue monitoring apparatus for monitoring all the evaporation residue of the condensed water supplied as the injection water, diluted with <br/> impurities condensed water supplied by the ultra-pure water as the water jet air cleaning system comprising: the water purifier to reduce the concentration, and a control device for controlling the dilution with ultrapure water in the water purifier by the output signal of the total evaporation residue monitoring device. 3. The ultrapure water supply line according to claim 2, wherein the water purification device is an ultrapure water supply line that discharges part of the water in the buffer tank and supplies ultrapure water to the buffer tank. Air purification system. 4. The water purification device according to claim 1, further comprising a plurality of sub-buffer tanks each having an inlet pipe , an outlet pipe, and a drain pipe each having a valve, and an inlet pipe of each sub-buffer tank being connected in parallel. First to connect to outlet pipe
And a second communication pipe connecting the outlet pipes of the sub-buffer tanks in parallel and connecting to a water supply pipe of a water spray nozzle of an air washer of the air cleaning device; A circulating pump provided in the second communication pipe, a control device for operating each of the valves, and an ultra pure
The air purification system according to claim 1, further comprising an ultrapure water supply pipe for supplying water . With 5. The total evaporation residue渣監vision device, any one of claims 1 to 4, characterized in that immediately <br/> Bei at least one measurement or analysis apparatus capable of organic components in water 1 The air purification system according to any one of the preceding claims.