JP2001355823A - Thermal oxidizing and decomposition type waste gas treating device and operating method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal oxidizing and decomposing type waste gas treating device and the operating method of the device capable of reducing an electric power consumption while effecting the removal treatment of poisonous constituents surely. SOLUTION: A heater installed in the thermal oxidizing and decomposing type waste gas treating device is divided into a plurality of series and the operation of respective heaters is controlled in accordance with the condition of the poisonous constituents in waste gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal oxidative decomposition type exhaust gas treatment apparatus and a method of operating the same, and more particularly, to the combustion of monosilane, dichlorosilane, phosphine, etc. contained in exhaust gas discharged from a semiconductor or liquid crystal manufacturing apparatus. The present invention relates to a thermal oxidative decomposition type exhaust gas treatment apparatus for detoxifying harmful components such as nonflammable or combustible gases such as reactive gas and ethane hexafluoride and nitrogen trifluoride by thermal oxidative decomposition treatment and a method of operating the same.

[0002]

2. Description of the Related Art Harmful gases such as toxic gases, corrosive gases, flammable gases, and non-flammable gases that adversely affect the global environment are contained in exhaust gas discharged from semiconductor manufacturing processes such as semiconductor manufacturing equipment and liquid crystal manufacturing equipment. Since the components are contained, it is necessary to perform the detoxification (detoxification) treatment of these harmful components before discharging the exhaust gas. 2. Description of the Related Art As one of the apparatuses for removing exhaust gas, a thermal oxidation decomposition type exhaust gas processing apparatus described in, for example, JP-A-10-85555 is known.

[0003] In this thermal oxidation decomposition type exhaust gas treatment apparatus, exhaust gas is introduced into a reactor containing an electric heater, and the exhaust gas is heated to 1000 ° C or more by the electric heater to thermally oxidize and decompose harmful components. Like that.

[0004]

However, the conventional thermal oxidative decomposition type exhaust gas treatment apparatus does not perform harmful treatment of exhaust gas or the like, or flammable gas in which harmful components in exhaust gas are relatively easily thermally decomposed. Even in the case of (1), since the electric heater is always operated, the power consumption becomes extremely large, the running cost of the detoxification treatment is increased, and the production cost of semiconductors and the like may be affected.

Accordingly, an object of the present invention is to provide a thermo-oxidative decomposition type exhaust gas treatment apparatus capable of reducing power consumption while reliably performing harmful component removal treatment and an operation method thereof.

[0006]

Means for Solving the Problems To achieve the above object, a thermal oxidative decomposition type exhaust gas treatment apparatus of the present invention heats exhaust gas with a heater to oxidize and decompose harmful components in the exhaust gas to render them harmless. The oxidative decomposition type exhaust gas treatment apparatus is characterized in that the heater is divided into a plurality of systems, and a control device is provided for controlling the operation of each heater according to the state of harmful components in the exhaust gas.

[0007] A method of operating a thermal oxidation decomposition type exhaust gas treatment apparatus according to the present invention is an operation method of a thermal oxidation decomposition type exhaust gas treatment apparatus having the above-mentioned structure, wherein harmful components in the exhaust gas flowing into the apparatus are analyzed. The operation of each heater is controlled via the control device based on the analysis result.

[0008]

1 and 2 show an embodiment of a reactor in a thermal oxidative decomposition type exhaust gas treatment apparatus according to the present invention. FIG. 1 is a longitudinal sectional view, and FIG. 2 is II in FIG. FIG. 2 is a sectional view taken along line II. The gas washing equipment and filters provided before and after the reactor can be formed in the same manner as in the prior art, so that illustration and detailed description are omitted.

First, a reactor 11 of a thermal oxidation decomposition type exhaust gas treatment apparatus has a large-diameter cylindrical main heater 12 and a small-diameter cylindrical sub-heater 13 concentrically arranged in a cylindrical closed vessel. The first and second heaters 12, 13 and the sub-heater top plate 14 and the main heater bottom plate 15 form a first flow path 16 on the inner circumference of the sub-heater 13, a second flow path 17 between the inner circumference of the main heater and the outer circumference of the sub-heater, Third flow paths 18 are formed between the outer periphery of the main heater and the inner periphery of the container.

Exhaust gas to be subjected to detoxification treatment is supplied to the sub heater 1
3 through the gas inflow pipe 19 opened to the upper inside.
And flows down the first flow path 16 while being heated by the sub-heater 13. The exhaust gas flowing out of the first flow path 16 hits the main heater bottom plate 15 and is inverted.
7 rise inside. Further, the exhaust gas that has flowed out of the second flow path 17 hits the sub-heater top plate 14, is inverted, descends in the third flow path 18 while being heated by the main heater 12, and is provided at the lower end of the reactor 11. It is discharged from the exhaust pipe 20.

During normal operation, both the main and sub heaters 12 and 13 are energized to heat the exhaust gas to a high temperature of 1000 ° C. or more, and the non-combustible gas such as ethane hexafluoride and nitrogen trifluoride and the combustion support Performs thermal oxidative decomposition treatment of various harmful components including gas.

When the harmful components in the exhaust gas are only flammable gas such as monosilane, the main heater 1
The power supply to the second or sub-heater 13 is stopped, and only one of the heaters is operated. At this time,
It is difficult to heat the exhaust gas to 1000 ° C. or more with only one heater, but when the harmful component is a flammable gas, for example, monosilane and phosphine spontaneously ignite even at room temperature. , Can be treated to a concentration lower than the allowable concentration.

As described above, the heaters 12 and 13 are operated only when the non-combustible gas or the supporting gas flows into the reactor 11, and only one heater is operated when only the combustible gas flows. By doing so, power consumption can be significantly reduced. In addition, by operating one of the heaters and maintaining the temperature at a certain level or more, the rise when the non-combustible gas or the supporting gas flows in can be performed in a short time.

The turning on and off of the main heater 12 and the sub-heater 13 can be performed by a control device (not shown) having a simple configuration such as a changeover switch. When the type of the harmful component is determined, the operation of the heater can be manually switched according to the operating condition, and the heater can be switched by a signal linked to the operation of the exhaust gas generation source. Also, capacity control can be performed instead of on / off.

The structure of the reaction vessel and the arrangement of the heater therein, the shape of the flow path, and the like are arbitrary, and an appropriate structure can be adopted according to the conditions such as the throughput and the like. It is also possible to perform the heater control in two or more stages by dividing into two.

FIG. 3 shows an embodiment of the method of the present invention, and is a schematic system diagram showing an example in which the heater is automatically controlled regardless of the operating condition of the exhaust gas generation source. . In the present embodiment, an analyzer 23 for analyzing harmful components in exhaust gas is installed in an exhaust gas path 22 from an exhaust gas source 21 such as a semiconductor manufacturing apparatus or a liquid crystal manufacturing apparatus to a reactor 11 of a thermal oxidation decomposition type exhaust gas processing apparatus. Then, based on the analysis result of the analyzer 23, the controller 12 controls the heaters 12, 1.
3 is controlled.

For example, a Fourier transform infrared spectrometer (FT-IR) is used as the analyzer 23 to analyze nonflammable and combustible harmful components that require high-temperature processing. Alternatively, when these concentrations become equal to or higher than the predetermined concentration, the heaters 12 and 13 are activated via the control device 24. If these are not detected, for example, the sub-heater 13 is energized via the control device 24. The thermal decomposition process is stopped and the main heater 12 alone is used.

Further, by using both the control using the analyzer 23 and the control using the signal linked to the operation of the exhaust gas generation source 21 described above, reliable detoxification processing with minimum power consumption can be achieved. Driving can be performed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the structure shown in FIGS. 1 and 2, the surface temperature of the main heater is 1200.degree.
A gas having a total flow rate of 200 L / min by diluting 1 L / min of ethane hexafluoride with nitrogen was introduced into the reactor set at 0 ° C., and the detoxification treatment was performed for 1 hour. The concentration of ethane hexafluoride in the gas discharged from the reaction vessel was determined by FT-IR
(Midac I-2000).
It was stable at about 00 ppm. The power consumption at this time was 12 kW.

Next, while the operation of the main heater is stopped, 2 L / min of monosilane is diluted with nitrogen to introduce a gas having a total flow rate of 200 L / min into the reaction vessel, and the gas is removed only by the sub-heater. Damage treatment was performed for 1 hour.
The concentration of monosilane in the gas discharged from the reaction vessel was measured with a gas detector (TG-4000TA manufactured by Bionics), and was always less than 5 ppm. The power consumption at this time was 8 kW.

That is, when the harmful component is only a flammable gas such as monosilane, the power consumption of 4 kW per hour can be saved by stopping the main heater and performing the detoxification process.

[0022]

As described above, according to the present invention,
The power consumption can be reduced while reliably performing the abatement treatment by the thermal oxidative decomposition treatment, and the running cost of the abatement treatment can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a reactor in a thermal oxidation decomposition type exhaust gas treatment apparatus of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a schematic system diagram showing one embodiment of the method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Reactor, 12 ... Main heater, 13 ... Sub heater, 14 ... Sub heater top plate, 15 ... Main heater bottom plate, 16 ... First flow path, 17 ... Second flow path, 18 ... Third flow path, 19 ... gas inflow pipe, 20 ... exhaust pipe, 21 ... exhaust gas generation source, 22 ... exhaust gas path, 23 ... analyzer, 24 ... control device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shuyasu Tomita 1-16-7 Nishi-Shimbashi, Minato-ku, Tokyo Inside Nippon Sanso Corporation (72) Inventor Shuichi Koseki 1-16-7, Nishi-Shimbashi, Minato-ku, Tokyo Japan Within Oxygen Co., Ltd.

Claims (2)

[Claims] 1. A thermo-oxidative decomposition type exhaust gas treatment apparatus that heats exhaust gas with a heater to oxidize and decompose harmful components in the exhaust gas to render it harmless. A thermo-oxidative decomposition type exhaust gas treatment device, comprising a control device for controlling the operation of each heater according to the state of the components. 2. The method for operating a thermal oxidative decomposition type exhaust gas treatment apparatus according to claim 1, wherein harmful components in the exhaust gas flowing into the apparatus are analyzed, and based on the analysis result, the harmful component is passed through the control device. A method for operating a thermal oxidation decomposition type exhaust gas treatment apparatus, wherein the operation of each heater is controlled.