JP2000197807A - Waste gas treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste gas treatment apparatus capable of stably and safely treating a waste gas containing organic silicon compounds by high temperature oxidation method. SOLUTION: This waste gas treatment apparatus comprises a waste gas supplying means 1 for supplying a waste gas containing organic silicon compounds to the heat receiving side of a heat exchanger 2, the heat exchanger 2 for carrying out heat exchange between the waste gas in the heat receiving side and a waste gas in the heat radiating side, a heating means 3 for heating the waste gas which is passed through the heat receiving side of the heat exchanger 2, and a reaction part 4 for decomposing the high temperature waste gas obtained from the heating means 3 by oxidation and the apparatus is further provided with a water sprinkling means 7 for sprinkling water to the heat radiating side of the heat exchanger 2 and a wastewater discharging means for discharging wastewater after sprinkling water out of the system of the waste gas treatment apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas treatment apparatus for treating an exhaust gas containing organic silicon by a high-temperature oxidation treatment method, and more particularly to an exhaust gas treatment apparatus for producing an organic silicon-containing exhaust gas in semiconductor production or liquid crystal production. It can be suitably applied to processing.

[0002]

2. Description of the Related Art Conventionally, a high-temperature oxidation treatment apparatus, that is, a combustion apparatus has been widely used as a treatment apparatus for purifying harmful gases containing flammable harmful substances.

The flow of a general high-temperature oxidizing apparatus for harmful gases is as shown in FIG. 1, for example. A harmful gas is sent to the heat receiving side of a heat exchanger 2 via a blower 1 and then exhausted after processing. The heat is indirectly recovered from the fuel, and the temperature is raised to a predetermined temperature by a burner 3 as a heater. The temperature at this time is generally set to 750 ° C. or higher, and the high-temperature exhaust gas after the treatment is passed through the heat-dissipating side of the heat exchanger 2 and released to the atmosphere.

In the above, when harmful gases are treated by a high-temperature oxidation treatment apparatus, generally, flammable harmful substances are liable to be oxidized in many cases, and the amount thereof is extremely small.
It was thought that the organic silicon oxide was released to the atmosphere without adhering to the heat transfer surface of the heat exchanger. Therefore, clogging on the heat radiating side of the heat exchanger 2 hardly occurs, and no countermeasure against clogging on the heat radiating side of the heat exchanger has been made.

However, a part of the organic exhaust gas in the semiconductor manufacturing process and the liquid crystal manufacturing process contains hexamethyldisilazane, which is a kind of organic silicon, and this exhaust gas is shown in a conventional apparatus, that is, FIG. When the heat treatment is performed by the high-temperature oxidation treatment apparatus using the
However, there is a problem that silicon dioxide, which is an oxide of organic silicon, adheres and accumulates on the heat transfer surface on the heat radiation side, and the heat exchanger is clogged in an extremely short time.

Further, when the heat exchanger is clogged, the processing air volume is reduced, and sufficient processing is not performed.
When a burner is used as a heater, there is a risk that the burner may be misfired, incompletely burned, and even fall into a dangerous state.

On the other hand, it is not easy to completely remove silicon dioxide adhering to the heat transfer surface of the heat exchanger. In the worst case, it is necessary to replace the heat exchanger. Extremely high costs were required.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and it is an object of the present invention to carry out high-temperature oxidative decomposition of exhaust gas containing a relatively large amount of organic silicon which is hardly oxidized. In addition, the present invention provides an exhaust gas treatment apparatus which does not cause clogging or incomplete combustion and does not require a large repair cost.

When the present inventors consider means for easily removing deposits generated during high-temperature oxidation treatment of an exhaust gas containing organic silicon, first, the deposits are chemically analyzed, and as a result, Although it contains some soot and the like, it has been found that silicon dioxide is essentially composed of silicon dioxide.

Further, the inventors of the present invention have conducted intensive studies on the above-mentioned means for peeling off and removing the deposit containing silicon dioxide as a main component. As a result, the deposit of silicon dioxide, which is originally incompatible with water, is added to water. Surprisingly, water penetrates into the sediment and disturbs the shape of the sediment, and at the same time, water penetrates between the metal such as stainless steel and the sediment to easily separate the sediment I found something.

The present inventors have made further studies based on the above findings, and have reached the present invention.

[0012]

In other words, exhaust gas supply means for supplying exhaust gas containing organic silicon to the heat receiving side of the heat exchanger, heat exchange between the exhaust gas on the heat receiving side and the exhaust gas on the heat radiating side. Heat exchanger for heating the exhaust gas passing through the heat receiving side of the heat exchanger, and a reaction unit for oxidatively decomposing the high-temperature exhaust gas obtained by the heating means Provided is an exhaust gas treatment device, comprising: a water spraying unit for spraying water to a heat radiation side of the heat exchanger; and a drainage unit for discharging wastewater after watering to the outside of the exhaust gas treatment unit. Things.

A preferred embodiment of the exhaust gas treatment apparatus according to the present invention is arranged such that a pressure difference between an inlet and an outlet on the heat radiating side of the heat exchanger and / or a pressure for detecting a pressure at an inlet on the heat radiating side of the heat exchanger are provided. It has a detecting means.

[0014] In a preferred embodiment of the exhaust gas treatment apparatus of the present invention, the heat exchanger is a flat plate flow type heat exchanger having a stainless steel heat transfer surface.

In a preferred embodiment of the exhaust gas treatment apparatus of the present invention, the flow of the exhaust gas on the heat radiation side of the heat exchanger is a downward flow from above to below.

In a preferred embodiment of the exhaust gas treatment apparatus according to the present invention, a chamber for collecting waste water is provided at an outlet on the heat radiation side of the heat exchanger.

In a preferred embodiment of the exhaust gas treatment apparatus of the present invention, the water spraying means and / or the chamber has a structure capable of being mounted and demounted.

Further, the present invention provides an exhaust gas processing apparatus having the above-described exhaust gas processing apparatus installed in two systems.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The exhaust gas treatment apparatus of the present invention is preferably applied to exhaust gas containing organic silicon, for example, alcohols, ketones, aliphatic hydrocarbons having a concentration of several thousand ppm or less, The present invention can be suitably applied to an exhaust gas containing an organic solvent such as an aromatic hydrocarbon.

The above-mentioned exhaust gas is not limited to so-called exhaust gas discharged from exhaust systems of various factories. For example, exhaust gas containing a low-concentration organic solvent is removed by an adsorption-type concentrator. As a matter of course, the concentrated gas and the like obtained by the treatment include a gas that is not called an exhaust gas.

In the above adsorption type concentrating apparatus, for example, exhaust gas containing a low-concentration organic solvent is passed through the adsorbing portion of the continuously rotating honeycomb adsorber, purified, and is also passed through the desorbing portion of the adsorbent. The organic solvent adsorbed on the adsorbent is desorbed by the small amount of high-temperature desorbed air. As a result, the adsorbent is continuously regenerated, and the concentrated gas containing the organic solvent is taken out of the adsorption-type concentrating device. Organic silicon having a relatively low boiling point, such as hexamethyldisilazane or its decomposition product, trimethylsilanol, is concentrated by the adsorption-type concentrator. In other words, when the concentrated gas is present at a relatively high concentration and the concentrated gas is treated by a high-temperature oxidation treatment method, a large amount of deposits, which are organic silicon oxides mainly composed of silicon dioxide, may be generated. In many cases, in such a case, the exhaust gas treatment method of the present invention exhibits excellent effects.

The exhaust gas treatment apparatus of the present invention can be more suitably applied when the organic silicon contained in the exhaust gas is an organic silicon having an alkylsilane group.

The term "organic silicon having an alkylsilane group" as used herein means, for example, organic silicon having a siloxane bond, a silazane bond, a silanol bond or the like.

Hexamethyldisilazane and its hydrolysis product, trimethylsilanol, are particularly used in the semiconductor manufacturing process and the liquid crystal manufacturing process, or are organosilicons generated in large quantities. When high-temperature oxidation treatment is performed, clogging in the heat exchanger occurs remarkably, and these organic silicons are substances that are extremely difficult to remove from the exhaust gas before the high-temperature oxidation treatment. When an exhaust gas containing organic silicon is to be processed, the exhaust gas processing apparatus of the present invention can be particularly suitably applied.

In the present invention, the deposit, which is an oxide of organosilicon, contains silicon dioxide as a main component.

It should be noted that the sediment includes soot of incomplete combustion, organic silicon to be treated, chemical changes thereof, and other components in exhaust gas, in addition to silicon dioxide. As long as it is a component, the present invention can be applied.

A typical form of the deposit is a solid obtained by compressing fine powders and granules, and the deposit adheres to the inner walls of various pipes, tools, fixtures, and devices, and is compressed air or brushing. In some cases, it is often difficult to remove.

The heating means in the exhaust gas processing apparatus of the present invention is not particularly limited, and may be any processing means for obtaining a harmless exhaust gas by oxidizing and decomposing a harmful organic solvent contained in the exhaust gas at a high temperature. Any means may be used.

In the exhaust gas treatment apparatus of the present invention, the heating means has a high-temperature oxidation treatment temperature, that is, a temperature in the high-temperature reaction section is 750 ° C. or more, and the residence time of the exhaust gas in this reaction section is 0.5 seconds. As described above, it is preferable that the high-temperature oxidation treatment is performed under the condition of preferably 1.0 second or more.

The heat exchanger for exchanging heat between the exhaust gas on the heat receiving side and the exhaust gas on the heat radiating side in the exhaust gas treatment apparatus of the present invention is not particularly limited.
A flat plate type heat exchanger (FIG. 3), a multi-tube heat exchanger (FIG. 4) and the like are preferably used.

In the exhaust gas treatment apparatus of the present invention, a heat exchanger having a structure in which deposits adhering to the heat transfer side heat transfer surface of the heat exchanger are easily sprinkled and removed is more preferable. The heat exchanger of the type is particularly preferable because the space between the heat transfer surfaces is relatively wide, and the heat exchanger has a structure in which the sediment is easily sprinkled and removed.

The material of the heat transfer surface of the heat exchanger is preferably made of stainless steel. This is because stainless steel not only has excellent heat resistance but also has a high effect of preventing corrosion due to water spray.

In the exhaust gas treatment apparatus of the present invention, the water spraying means for spraying water to the heat radiating side of the heat exchanger is not particularly limited.
Means for applying to the sediment are preferably used. With such means, it is possible to evenly pour water on the deposits deposited on the heat radiation side of the heat exchanger.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 2 is a flow chart 1 of the processing apparatus of the present invention.
An example is shown. The gas to be treated is sent through a blower 1 to the heat receiving side of a flat plate type heat exchanger 2 having a heat transfer surface made of stainless steel, indirectly recovering heat from the treated high-temperature exhaust gas, and further using a heater. The temperature is raised to a predetermined temperature by a certain burner 3. The combustible harmful substances are oxidatively decomposed in the high-temperature reaction section 4. The high-temperature exhaust gas after the treatment is passed to the heat-dissipating side of the heat exchanger 2 via the introduction portion 5 to the heat-dissipating side of the heat exchanger 2, and after releasing heat, is discharged to the atmosphere. The heat exchanger 2 is provided with a pressure gauge 6 for measuring a pressure difference between an inlet and an outlet on the heat radiating side, and monitors the state of clogging with silicon dioxide on the heat radiating side of the heat exchanger. Heat exchanger 2
Is provided with a sprinkling line 7 for sprinkling water to the heat radiation side. Further, a drain line 8 for discharging washing wastewater at the time of sprinkling is provided on the heat radiation side of the heat exchanger.

Silicon dioxide adheres and accumulates on the heat transfer surface on the heat radiating side of the heat exchanger, causing clogging on the heat radiating side of the heat exchanger. When the indicated value of 5 reaches a predetermined pressure, the temperature rise of the gas to be treated by the burner 3 is stopped, and the blower 1 is stopped after the heat exchanger is cooled to about room temperature. Thereafter, water is sprinkled from the water sprinkling line 7, and the silicon dioxide deposited on the heat exchanger is washed away. The cleaning wastewater containing silicon dioxide generated at this time is
It is discharged through the drain line 8 to the outside of the heat exchanger.

An example of a detailed partial view of an exhaust gas treatment apparatus according to the flow of FIG. 2 using the present invention is shown in FIG. As the heat exchanger 2, a flat plate type flow heat exchanger whose heat transfer surface is made of stainless steel is used. The temperature of the high-temperature exhaust gas from the reaction section 4 is usually 750 ° C. or higher. Heat insulating materials 4a and 5a for protecting the inner surface from heat are attached. Reaction part 4
The high-temperature exhaust gas is passed through the inlet pipe 5 to the heat-radiation-side inlet opened below the heat exchanger 2. The high-temperature exhaust gas is ventilated upward from the heat-dissipating side of the heat exchanger upward, during which heat of the exhaust gas is recovered.
Through the atmosphere. In order to remove silicon dioxide attached and deposited on the heat transfer surface on the heat radiating side of the heat exchanger 2, water is sprayed from the heat radiating side outlet 2b of the heat exchanger 2 through the water spray line 7.

Another example of a detailed partial view of an exhaust gas treatment apparatus according to the flow of FIG. 2 using the present invention is shown in FIG. As the heat exchanger 2, a flat plate type flow heat exchanger whose heat transfer surface is made of stainless steel is used. The gas is passed through a high-temperature exhaust gas introduction pipe 5 from the reaction section 4 to a heat-radiation-side inlet opened above the heat exchanger 2. The high-temperature exhaust gas is ventilated in a downward flow from above to the heat-dissipating side of the heat exchanger in a downward flow. During this time, the heat of the exhaust gas is recovered and then discharged to the atmosphere through the atmosphere discharge pipe 9. The temperature of the exhaust gas vented to the atmosphere discharge pipe 9 is 400 ° C. or less, and it is not necessary to provide a heat insulating material on the inner surface of the atmosphere discharge pipe 9 to protect the inner surface from heat. In order to remove silicon dioxide deposited and deposited on the heat transfer surface on the heat radiation side of the heat exchanger 2, water was sprayed from the heat radiation side inlet 2 a of the heat exchanger 2 through the water spray pipe 7. The wastewater containing the fine powder of silicon dioxide was discharged from the heat radiation side outlet 2b of the heat exchanger 2, and further discharged out of the system through a drainage line 8 provided at the bottom of the air discharge pipe. Thereby, the reaction section 4 and the introduction section 5
The heat insulating material attached to the inner surface of the heat exchanger was not damaged by water infiltration, and the silicon dioxide adhered and deposited on the heat transfer surface on the heat radiation side of the heat exchanger 2 was completely washed and removed.

With respect to the processing apparatus shown in FIG. 6, a processing apparatus in which a chamber 10 for receiving waste water is provided between the heat radiation side outlet 2b of the heat exchanger 2 and the atmosphere discharge pipe 9
As shown in FIG. A drain line 8 for discharging waste water containing fine powder of silicon dioxide is attached to the bottom of the chamber 10. By attaching the chamber 10, waste water containing fine powder of silicon dioxide is completely discharged out of the system. The chamber 10 is desirably made of stainless steel.

In the processing apparatus shown in FIG. 7, the temperature of the heat-dissipating-side inlet 2b of the heat exchanger 2 during processing is extremely high at 750 ° C., and the water sprinkling line is connected to the heat-dissipating-side inlet 2b of the heat exchanger 2. To keep it installed inside at all times,
An extremely expensive material having excellent heat resistance must be used for the water sprinkling tube 8, which is not very preferable. Therefore,
While the sprinkler pipe insertion port is provided and the oxidative decomposition treatment is being performed, the sprinkler pipe 8 is removed from the inside of the heat radiation side inlet of the heat exchanger 2, and the carbon dioxide deposited and deposited on the heat radiation side heat transfer surface of the heat exchanger 2. When removing the silicon, after cooling the heat exchanger, the sprinkler tube 8 is inserted into the heat-radiation-side inlet 2b of the heat exchanger 2 through the sprinkler tube insertion port, and the silicon dioxide deposited and deposited on the heat exchanger is removed. It is desirable to remove by washing.

FIG. 8 shows another example of the processing method of the present invention. In this example, two systems, that is, systems A and B are installed. First, the gas to be processed is processed in the A system. That is, the gas to be processed is the opened switching damper 8.
A, the heat is sent to the heat receiving side of the blower 1A and the flat plate type heat exchanger 2A made of stainless steel, and the heat is indirectly recovered from the treated high-temperature exhaust gas. The temperature is raised to the temperature. The combustible harmful substances are oxidatively decomposed in the high-temperature reaction section 4A.
The high-temperature exhaust gas after the treatment is passed through the heat-dissipating side of the heat exchanger and released to the atmosphere. The heat exchanger 2A is provided with a pressure gauge 5A for measuring a pressure difference between an inlet and an outlet on the heat radiating side, and monitors the state of clogging with silicon dioxide on the heat radiating side of the heat exchanger. Further, the heat exchanger 2A is provided with a sprinkling line 6A for sprinkling water to the heat radiation side. Further, a drainage line 7A for discharging washing wastewater at the time of sprinkling is provided on the heat radiation side of the heat exchanger 2A. At this time, the outside air intake dampers 9A and 9B are closed. The equipment of the other processing system, system B, is stopped. That is,
The switching dambar 8B is closed, and the blower 1B and the burner 3B are stopped.

Silicon dioxide adheres and accumulates on the heat transfer surface of the heat exchanger 2A on the radiating side, and clogging occurs on the radiating side of the heat exchanger.
When the pressure difference between the heat exchanger heat radiation side inlet and outlet rises and the indicated value of the pressure gauge 5A reaches a predetermined pressure, the outside air intake damper 9B is opened while the switching damper 8A is closed, and the blower 1B is opened. Is activated. Further, when the burner 3B is activated and the temperature of the reaction section 4B reaches a temperature sufficient for performing the high-temperature oxidation treatment, the switching damper 8B is opened, the outside air intake damper 9B is closed, and the outside air intake damper 9B is closed. At the same time as 9A is opened, the switching damper 8A is closed. Thereby, the processing equipment for the gas to be processed is switched from the A system to the B system. Further, after the burner 3A is stopped and the heat exchanger 2A is cooled,
The blower 1A is stopped. After that, water is sprayed from the water spray line 6A to the heat exchanger radiation side, and the deposited silicon dioxide is washed away. The wastewater containing silicon dioxide generated at this time is discharged to the outside of the heat exchanger through the drainage line 7A. When these steps are completed, the blower 2A is started again, and after drying the heat exchanger 2A, it is stopped again. Further, the outside air intake damper 9A is closed, and A
The system equipment is stopped. It is desirable that these operations be performed automatically.

[0043]

EXAMPLES (Example 1) Hexamethyldisilazane was added to about 1
0 ppm, an organic solvent mainly composed of butyl acetate is 3000
Figure 2 using the present invention for exhaust gas containing ppm
The high-temperature oxidation treatment was performed by the processing apparatus shown in FIG. As the heat exchanger 2, a flat plate type heat exchanger having a heat transfer surface made of stainless steel is used, and the high-temperature exhaust gas after the high-temperature oxidation treatment flows downward from above the heat radiation side of the heat exchanger 2 downward. Ventilated. The burner 3 has LPG
Was used as fuel. The temperature of the reaction section 4 is controlled to be 750 ° C.

The indicated value of the pressure gauge was 50 mmAq at the beginning of the high temperature oxidation treatment. At this time, the removal efficiency of butyl acetate was as extremely good as 99% or more. After about one week of the high-temperature oxidation treatment, the indicated value of the pressure gauge 6 rose to the set pressure of 100 mmAq. At this time, the removal efficiency of butyl acetate was as good as 99% or more. Further, no decrease in the processing air volume was particularly observed. Thereafter, the burner 3 was stopped, and the high-temperature oxidation treatment was stopped. The heat exchanger 2 was cooled to about 60 ° C. in about 1 to 2 hours. Thereafter, the blower 1 was stopped, and water was sprinkled from the water sprinkling line 7 downward for about 10 minutes from the heat radiation side inlet 2a opened above the heat exchanger 2. Sprinkling was performed evenly over the entire opening surface of the heat exchanger without anybody entering the heat exchanger. Waste water in which a large amount of silicon dioxide white powder is dispersed is supplied to a waste water receiving chamber 1
The wastewater was discharged from a drain line 8 attached to the discharge line 0. After no white powder of silicon dioxide was found in the wastewater, the blower 1 and the burner 3 were restarted, the temperature of the reaction section 4 was raised to a steady processing temperature of 750 ° C., and the processing was restarted. The time from the restart of the blower 1 until the temperature of the reaction section 4 reached the steady temperature was about 30 minutes. The indicated value of the pressure gauge 5 dropped to 50 mmAq, the value at the beginning of the high-temperature oxidation treatment. The removal rate of butyl acetate was extremely good at 99% or more.

The time required for removing the silicon dioxide deposited on the heat exchanger from the stop to the restart of the high-temperature oxidation treatment was about 2 hours and 30 minutes. Further, when the blower 1 was restarted, almost no white powder of silicon dioxide was found in the exhaust gas from the heat exchanger radiation side, that is, the exhaust gas discharged to the atmosphere.

Further, when the treatment was continued, the indication value of the pressure gauge 5 increased to 100 mmAq again in about one week as in the previous case. For this reason, the same operation was repeatedly performed.

Comparative Example 1 About 10 ppm of hexamethyldisilazane and 300 parts of an organic solvent mainly composed of butyl acetate were used.
Exhaust gas containing 0 ppm was subjected to a high-temperature oxidation treatment according to the flow sheet of FIG. 1 using a conventional treatment method. As the heat exchanger 2, a stainless steel flat plate heat exchanger was used. The burner 3 used LPG as fuel. The temperature of the reaction section 4 is controlled to be 750 ° C.

The efficiency of removing butyl acetate at the beginning of the high-temperature oxidation treatment was as extremely good as 99% or more. Since the pressure on the heat radiating side of the heat exchanger 2 is not monitored and the state of clogging on the heat radiating side of the heat exchanger cannot be grasped, about two weeks after the start of the high-temperature oxidation treatment, the burner 3 often misfires. Occurred, and sufficient high-temperature oxidation treatment could not be performed. Also, the processing air volume was reduced to 50% or less of the time when the high-temperature oxidation treatment was started. Therefore, the burner 3 was stopped, and the high-temperature oxidation treatment was stopped. Thereafter, the heat exchanger 2 was cooled to about 30 ° C. at which no problem occurs when a person enters the inside of the heat exchanger. About 6 for cooling
Time was needed. Thereafter, the blower 1 was stopped, and a person entered the heat exchanger 2 to perform an inspection. As a result, it was found that the heat radiation side was completely clogged. A black substance was deposited on the heat radiation side of the heat exchanger. When this deposit was analyzed, it was found that these substances were a mixture of carbon caused by soot generated by incomplete combustion of the burner 3 and silicon dioxide which is an oxide of hexamethyldisilazane.

(Comparative Example 2) As in Comparative Example 1, high-temperature oxidation treatment was performed on exhaust gas containing about 10 ppm of hexamethyldisilazane and 3000 ppm of an organic solvent mainly composed of butyl acetate according to the flow sheet of FIG. . As the heat exchanger 2, a flat plate type heat exchanger having a heat transfer surface made of stainless steel was used. The burner 3 used LPG as fuel. The temperature of the reaction section 4 is controlled to be 750 ° C.

The efficiency of removal of butyl acetate at the beginning of the high-temperature oxidation treatment was as excellent as 99% or more. The pressure on the heat radiation side of the heat exchanger 2 was not monitored, but from the results of Comparative Example 1, the burner 3 was stopped one week after the start of the high-temperature oxidation treatment, and the high-temperature oxidation treatment was stopped. Thereafter, the heat exchanger 2 was cooled to about 30 ° C. at which no problem occurs when a person enters the inside of the heat exchanger. About 6 hours were required for cooling. afterwards,
When the blower 1 was stopped and a person entered the heat exchanger 2 and inspected, it was confirmed that white silicon dioxide had accumulated on the heat transfer surface of the heat radiating portion. This deposit was first removed by a brush, and then an attempt was made to remove it with compressed air. However, the silicon dioxide was in close contact with the heat transfer surface of the heat exchanger 2, and it was impossible to completely remove the deposit. The time required to remove the sediment was about 3 hours.

Thereafter, the blower 1 and the burner 3 were restarted, the temperature of the reaction section 4 was raised to a steady processing temperature of 750 ° C., and the high-temperature oxidation processing was restarted. The time from the restart of the blower 1 until the temperature of the reaction section 4 reached the steady temperature was about 30 minutes.

It took about 9 hours and 30 minutes to stop and restart the high-temperature oxidation treatment in removing the silicon dioxide deposited on the heat exchanger.

Also, for a few minutes immediately after the blower 1 was started, it was observed that a large amount of white powder of silicon dioxide was mixed in the exhaust gas to the atmosphere.

Further, when the high-temperature oxidation treatment was continued, when the high-temperature oxidation treatment was performed for about one week, the burner 3 was frequently misfired, and it was difficult to perform a sufficient oxidative decomposition treatment. Was. Also, the processing air volume was reduced to 50% or less of the time when the processing was started.

[0055]

According to the exhaust gas treatment apparatus of the present invention, the exhaust gas containing the organic silicon is stably and efficiently oxidized at high temperature without any burnout of the burner and no decrease in the processing air volume. . Further, silicon dioxide deposited on the heat radiation side of the heat exchanger was easily removed in a very short time. Further, the removal effect was extremely high, and silicon dioxide could be almost completely removed from the heat transfer surface of the heat exchanger by washing. Furthermore, the residue of silicon dioxide remaining in the heat exchanger after cleaning and removal by this method is small, and it is clear that there is no risk of secondary pollution such as the residue of silicon dioxide being discharged to the atmosphere when the treatment is resumed. It became. As described above, the exhaust gas treatment apparatus of the present invention can be particularly suitably used in a semiconductor manufacturing process or a liquid crystal manufacturing process for discharging exhaust gas containing organic silicon, and the effect is great.

[Brief description of the drawings]

FIG. 1 is an example of a flow sheet of a conventional exhaust gas treatment device.

FIG. 2 is an example of a flow sheet of the exhaust gas treatment device of the present invention.

FIG. 3 is a planer flow type heat exchanger 1 used in the present invention.
It is an example.

FIG. 4 is an example of a multitubular heat exchanger used in the present invention.

FIG. 5 is an example of a detailed partial view of an exhaust gas treatment device of the present invention.

FIG. 6 is an example of a detailed partial view of an exhaust gas treatment device of the present invention.

FIG. 7 is an example of a detailed partial view of an exhaust gas treatment device of the present invention.

FIG. 8 is an example of a flow sheet of the exhaust gas treatment device of the present invention.

[Explanation of symbols]

 1, 1A, 1B Blower 2, 2A, 2B Heat exchanger 2a Heat exchanger radiating side inlet 2b Heat exchanger radiating side outlet 3, 3A, 3B Heater (burner) 4, 4A, 4B Reaction section 5 High-temperature exhaust gas introduction pipe 6 , 6A, 6B Pressure gauge 7, 7A, 7B Watering line 8, 8A, 8B Drainage line 9 Atmospheric discharge pipe 10 Chamber 11A, 11B Switching damper 12A, 12B Outside air intake damper

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F23J 15/04 F23J 15/00 D H01L 21/31 (72) Inventor Takeshi Kishimoto Kita-ku, Osaka-shi, Osaka 2-8-8 Dojimahama Toyobo Co., Ltd. Head Office F-term (reference) 3K070 DA01 DA35 DA53 3K078 AA04 BA03 BA20 BA21 CA13 4D002 AA26 AB03 AC10 BA05 BA12 BA13 BA14 CA01 EA05 EA09 GA01 GA02 GB02 GB03 GB04 HA03 HA06 HA08 5F045 AC07 BB10 EG07

Claims (7)

[Claims] An exhaust gas supply means for supplying an exhaust gas containing organic silicon to a heat receiving side of a heat exchanger, and a heat exchanger for exchanging heat between the heat receiving side exhaust gas and the heat radiating side exhaust gas. An exhaust gas treatment device having a heating unit for heating exhaust gas that has passed through the heat receiving side of the heat exchanger and a reaction unit for oxidatively decomposing high-temperature exhaust gas obtained by the heating unit, An exhaust gas treatment apparatus, comprising: a water sprinkling means for spraying water to a heat radiation side of the heat exchanger; and a drainage means for discharging waste water after water sprinkling to a system outside the exhaust gas treatment apparatus. 2. A pressure detecting means for detecting a pressure difference between an inlet and an outlet on a heat radiating side of the heat exchanger and / or a pressure at an inlet on a heat radiating side of the heat exchanger. 2. The exhaust gas treatment device according to 1. 3. The exhaust gas treatment apparatus according to claim 1, wherein the heat exchanger is a flat plate flow type heat exchanger having a stainless steel heat transfer surface. 4. The exhaust gas treatment device according to claim 1, wherein the flow of the exhaust gas on the heat radiation side of the heat exchanger is a downward flow from above to below. 5. The exhaust gas treatment apparatus according to claim 1, wherein a chamber for collecting waste water is provided at an outlet on a heat radiation side of the heat exchanger. 6. The exhaust gas treatment apparatus according to claim 1, wherein the water spraying means and / or the chamber have a structure that can be attached and detached. 7. An exhaust gas treatment device comprising the exhaust gas treatment device according to claim 1 installed in two systems.