JP2023144853A - Heat type detoxification device and heat type detoxification method using the same - Google Patents

Abstract

To provide a heat type detoxification device capable of achieving effective detoxification by an electric heater alone.SOLUTION: A heat type detoxification device 1 including a cylindrical chamber 2 and a heater part 3 fit on the inner peripheral surface 2a of the chamber 2 can directly pass and heat gas to be treated upward in the vertical direction in the inside of the heater part 3 to perform detoxification. The heater part 3 obtained by forming a planar or linear electric heater spiral in a plane view includes: a gas passage 6 consisting of an interval between the adjacent electric heaters and spiral in the plane view; and a rectification part 7 covering the upper part of the heater part 3. The rectification part 7 fit on the inner peripheral surface 2a of the chamber 2 has an exhaust hole 7a allowing the passage of treated gas in the central part.SELECTED DRAWING: Figure 1

Description

The present invention relates to a thermal abatement device and a thermal abatement method for safely discharging gas used in the manufacturing process of electronic products such as semiconductors.

Conventionally, there are various methods to remove harmful gases emitted from electronic product manufacturing factories. Thermal abatement treatment is applied to gases that can remove substances and hazardous substances.

The mainstream of thermal abatement devices is the combustion type using gas burners, and these combustion-type thermal abatement devices can efficiently heat the target gas to the temperature required for abatement treatment. While there are advantages, there are disadvantages such as the need for relatively large capacity extra utilities such as gas cylinders and combustion chambers, and safety concerns.

Therefore, in order to be able to safely perform detoxification treatment and to make the device itself compact, thermal detoxification devices have been developed that can thermally decompose the target gas by heating with an electric heater. , a thermal abatement device shown in Patent Document 1 below is known.

However, in the thermal abatement device of Patent Document 1 listed below, it is difficult to form a desired high-temperature atmosphere by heating with an electric heater alone, so as shown in Patent Document 2 below, A thermal abatement device that forms a desired high-temperature atmosphere by igniting fuel gas with an electric heater has been developed (paragraph 0009 of Patent Document 2).

Patent No. 3016690 Patent No. 3866412

As mentioned above, the actual situation with thermal abatement devices is that even if electric heaters are used to solve the concerns about the large size and safety of combustion-type devices, electric heaters alone are not necessary for thermal abatement. In the end, heating by combustion has been used instead.

Therefore, there is a need for a thermal abatement device that does not involve combustion and can perform effective abatement treatment simply by heating with an electric heater, that is, a thermal abatement device that can be downsized and does not require consideration of the dangers of combustion. has been done.

The present invention provides a thermal abatement device and a thermal abatement method using the device, which realize effective abatement treatment using the electric heater alone, by means of a heater structure characterized by the arrangement of the electric heater and a gas passage. I will provide a.

In summary, the thermal abatement device according to the present invention includes a cylindrical chamber and a heater part that fits into the inner circumferential surface of the chamber, and directs the gas to be treated upward in the vertical direction into the heater part. A thermal abatement device that performs abatement treatment by direct heating, and the heater section is formed by forming a planar or linear electric heater into a spiral shape in a plan view, and the electric heaters are adjacent to each other. It has a spiral gas passage in a plan view consisting of intervals, and is provided with a rectifying part that covers the upper part of the heater part, and the rectifying part fits into the inner circumferential surface of the chamber, and the processed gas is disposed in the center thereof. The structure has a discharge hole that allows the passage of.

Therefore, it is possible to effectively heat the target gas to the temperature required for thermal decomposition and perform detoxification treatment using electric heaters that are densely adjacent to each other in the direction perpendicular to the gas flow direction (vertical direction). There is no need to use heating means. Further, powder by-produced by thermal decomposition can be trapped in the gas passage, and there is no need to provide cleaning equipment such as a scrubber.

Preferably, the planar electric heater has a large number of gas holes passing through the surface, so that heating and trapping of by-product powder can be performed more efficiently.

Further, by providing a pressure sensor upstream of the heater section, it is possible to monitor whether or not the heater section is clogged with powder or the like produced as a by-product of thermal decomposition.

Preferably, a preheater section is provided upstream of the starting point of the gas flow path in the heater section, and the preheater section includes a truncated inverted conical reflector that covers the lower end of the heater section. Preheating can be performed by effectively utilizing the thermal energy of the heater section, making it possible to effectively suppress thermal decomposition and powder by-product production.

More preferably, a net made of metal that functions as a catalyst in the abatement process is disposed at the lower end opening of the reflector, thereby further promoting the highly efficient abatement process.

The thermal abatement method according to the present invention is a thermal abatement method using the above-mentioned thermal abatement device according to the present invention, in which a target to be treated is directed upwardly in the vertical direction in the gas flow path of the heater section. By directly passing the gas and heating it, it is possible to thermally decompose the gas to be treated and to trap the powder by-produced by the thermal decomposition, making it possible to perform safe and clean abatement treatment.

According to the thermal abatement device of the present invention, the arrangement structure in which the electric heaters are placed closely adjacent to each other in the direction perpendicular to the gas flow direction makes it possible to efficiently heat the gas to be treated and to trap by-product powder. Equipped with a gas passage structure, it enables thermal abatement by heating alone with an electric heater, and also contributes to the miniaturization and safety of the device.

In addition, according to the thermal detoxification method of the present invention, thermal decomposition treatment can be performed only by the heater section consisting of an electric heater without combustion, and safe detoxification treatment is possible. In addition, clean detoxification treatment is possible without using cleaning equipment such as a scrubber.

1 is a schematic diagram of a thermal abatement device using a planar electric heater according to the present invention. FIG. 2 is a diagram illustrating a heater section configured with a planar electric heater, in which (A) is a plan view of the heater section, (B) is a side view of the heater section, and (C) is a perspective view of the heater section. 1 is a schematic diagram of a thermal abatement device using a linear electric heater according to the present invention. FIG. 2 is a diagram illustrating a heater section composed of a linear electric heater, in which (A) is a plan view of the heater section, (B) is a side view of the heater section, and (C) is a perspective view of the heater section. FIG. 3 is a side view showing an example of a heater unit that combines a plurality of linear electric heaters.

An optimal embodiment of a thermal abatement device and a thermal abatement method using the device according to the present invention will be described with reference to FIGS. 1 to 5. In each figure, power sources and electric wires related to the electric heaters 4 and 5 are omitted.

<Basic configuration of thermal abatement device>
As shown in FIGS. 1 and 3, the thermal abatement device 1 according to the present invention includes a cylindrical chamber 2 and a cylindrical or conical heater section 3 that fits into the inner peripheral surface 2a of the chamber 2. The gas to be treated can be directly passed through the heater section 3 in an upward direction in the vertical direction to heat it and carry out the abatement treatment.

Therefore, by providing a gas inlet 2b at the lower end of the chamber 2 and a gas outlet 2c at the upper end thereof, and by fitting the heater part 3 into the inner circumferential surface 2a of the cylindrical chamber 2, the gas inlet can be carried in. The target gas carried into the chamber 2 through the opening 2b is not carried out through the gas outlet 2c without passing through the heater section 3.

Chamber 2 is suitable for thermal abatement treatment of stainless steel (SUS: Steel Use Stainless), heat-resistant steel (SUH: Steel Use Heat Resisting), Inconel (registered trademark), Hastelloy (registered trademark), etc. It is made of metal that has no influence, and its internal volume can of course be adjusted as appropriate, and the volume of the heater section 3 relative to the internal volume of the chamber 2 can also be adjusted as appropriate. As described later, it is preferable to use a resistance heating type electric heater for the heater section 3, and an insulating sheet is interposed between the inner circumferential surface 2a of the chamber 2 and the outer circumferential surface 3a of the heater section 3. It is desirable to prevent troubles due to short circuits, electrical leakage, etc.

Note that P in FIGS. 1 and 3 is a pipe for conveying the gas to be processed in the exclusion process and the processed gas, and C is a cooler for cooling the processed gas. The gas to be treated is transported from a semiconductor factory or the like to the thermal abatement device 1 through a pipe P, and is subjected to a detoxification process by the thermal abatement device 1 to become a treated gas, and the treated gas is cooled in a cooler. After that, it is transported through a pipe P and released into the atmosphere.

≪Configuration of heater section≫
As shown in FIGS. 1 and 2, the heater section 3 is formed by winding a planar electric heater 4 in a spiral shape when viewed from above to form a cylinder, or as shown in FIGS. The electric heater 5 is formed into a spiral shape in plan view. As the electric heater, a known electric heater can be used, but in order to form a high-temperature atmosphere necessary for thermal decomposition of the target gas at, for example, 600°C or higher, or even 1000°C or higher, it may be formed into a spiral shape in plan view. In order to achieve this, it is preferable to use an electric heater of a resistance heating type, and it is particularly preferable to use an electric heater whose heating resistor is a metal such as nichrome or Kanthal (registered trademark).

When using a planar electric heater 4, as shown in FIGS. 1 and 2, it is formed so that it has a spiral shape in plan view and a cylindrical overall shape. The interval, that is, the adjacent interval in a spiral shape in plan view is made as narrow as possible, and the adjacent interval is used as the gas flow path 6. Therefore, the heater portion 3 is formed by spirally winding the planar electric heaters 4 while keeping them as close to each other as possible, thereby forming the gas flow path 6 as narrow as possible.

In this way, by the arrangement structure in which the planar electric heaters 4 are placed closely adjacent to each other in the direction perpendicular to the gas flow direction (upward in the vertical direction), the gas flow path 6 can efficiently heat the gas to be processed. It has a structure that can trap by-product powder. In addition, in the present invention, as long as the gas flow path 6 can be provided, the case where the sheet electric heaters 4 partially contact each other is not excluded.

Further, although not specifically shown in the drawings, it is desirable that the planar electric heater 4 has a large number of gas holes passing through it. This is because it is possible to perform heating more efficiently and to trap powder by-produced by thermal decomposition. Further, depending on the implementation, it is optional to make the surface of the sheet electric heater 4 rough to make it easier to collect by-product powder.

Alternatively, when a linear heater 5 is used, as shown in FIGS. 3 and 4, it is formed so that it has a spiral shape in plan view and a conical overall shape, so that the linear electric heaters 5 are The adjacent interval, that is, the adjacent interval in a spiral shape in a plan view, is made as narrow as possible, and the adjacent interval is used as the gas flow path 6.

Therefore, when using the linear electric heater 5, as in the case of the planar electric heater 4, the gas flow path can be maintained by the arrangement structure in which the linear electric heaters 5 are closely adjacent to each other in the direction orthogonal to the gas flow direction. 6 has a structure that can efficiently heat the gas to be treated and can trap by-product powder. In addition, in the present invention, as long as the gas flow path 6 can be provided, the case where the linear heaters 5 partially contact each other is not excluded. Further, depending on the implementation, it is optional to make the surface of the linear heater 5 rough to make it easier to collect by-product powder.

Further, when using the linear electric heater 5, as shown in FIG. 5, a plurality of linear electric heaters 5 formed in a spiral shape in a plan view can be stacked to form the heater section 3, resulting in higher efficiency. heating and by-product powder trapping. The overall shape of the linear electric heater 5 formed into a spiral shape in a plan view is shown as a conical shape in this embodiment, but in the present invention, a truncated conical shape, an inverted conical shape, a truncated conical shape, etc. It is also optional to have an inverted conical head shape depending on the implementation.

In the present invention, the gas passage 6 in the heater section 3 has a starting point 6a at the lower end and a starting point 6a at the upper end, regardless of whether it is configured by the planar electric heater 4 or the linear electric heater 5. This becomes the end point 6b. This is because, as described above, the gas to be treated is carried in from the gas inlet 2b at the lower end of the chamber 2, and the gas to be treated comes into contact with the heater section 3 from below. This is also because the gas to be treated is heated, expands, and moves in the gas passage 6 from below to above.

Further, in the present invention, as described above, the arrangement structure in which the planar electric heaters 4 or the linear electric heaters 5 are closely adjacent to each other in the direction perpendicular to the gas flow direction allows gas flow in the heater section 3. The channel 6 is made as narrow as possible to achieve both highly efficient heating and trapping of by-product powder.

Therefore, there is a risk that the trapped by-product powder may clog the gas passage 6. However, in the present invention, a pressure sensor is provided upstream of the heater section 3 to prevent clogging of the heater section 3. The presence or absence can be monitored. Although the pressure sensor is not specifically shown, there is no limitation on the location where it is placed as long as it is upstream of the heater section 3, and it may be placed inside or outside the chamber 2.

It goes without saying that the heater section 3 is provided with a circuit for detecting troubles such as short circuits and leakage caused by bringing the planar electric heaters 4 or the linear electric heaters 5 close to each other.

≪Configuration of rectifier section≫
In the present invention, as shown in FIGS. 1 and 3, a rectifying section 7 is provided so as to cover the upper part of the heater section 3 described above. Like the chamber 2, the rectifier 7 is made of metal that does not affect thermal abatement treatment, such as stainless steel, heat-resistant steel, Inconel (registered trademark), Hastelloy (registered trademark), etc. 2a, and is disposed in close contact with or in the vicinity of the upper part of the heater part 3.

The rectifier 7 has a discharge hole 7a in the center that allows the processed gas to pass through, and the center of the heater 3 has the least loss of thermal energy, that is, the highest temperature. This is arranged to encourage the gas to be processed to pass through the axial section.

Therefore, as shown in FIGS. 1 and 3, the gas to be processed flowing through the gas passage 6 of the heater section 3 is guided by the rectifier 7 to the center of the heater section 3 as indicated by the arrow in the figure, and is heated. After the decomposition treatment, the treated gas is discharged from the discharge hole 7a. Therefore, only the electric heaters 4 and 5 can effectively heat the gas to be treated to a temperature necessary for thermal decomposition, and perform the abatement treatment.

Note that it is preferable that the rectifying part 7 has a shape that follows the shape of the upper part of the heater part 3. As shown in FIG. As shown in the figure, when the heater section 3 is conical, it is shaped like a conical tube to effectively cover the upper part of the heater section 3 and promote efficient gas passage to the heater section 3 of the gas to be treated. .

≪Configuration of preheater section≫
In the present invention, preferably, as shown in FIGS. 1 and 3, a preheater section 8 is provided upstream of the starting point 6a of the gas passage 6 in the heater section 3. The preheater section 8 allows preheating to be performed by effectively utilizing the thermal energy leaked from the heater section 3, making it possible to effectively suppress thermal decomposition and powder by-product production.

The pre-heater section 8 consists of a truncated inverted conical reflector 9 that covers the lower end of the heater section 3. By covering the lower end of the heater section 3 with the upper end opening 9b of the reflector 9, the pre-heater section 8 prevents leakage from the heater section 3. Heat energy can be collected by reflection and used effectively. The reflector 9 is made of a metal such as stainless steel that does not affect thermal abatement treatment and has good heat reflectivity.

More preferably, by arranging a net 10 made of a metal that functions as a catalyst in the detoxification process in the lower end opening 9a of the reflector 9, it is possible to promote more efficient detoxification process. Examples of metals that function as catalysts include platinum for hydrocarbon gases and nickel for ammonia gases.

<Thermal abatement method>
The thermal abatement method according to the present invention is a thermal abatement method using the above-mentioned thermal abatement device 1 according to the present invention, and has the following features.

That is, the gas to be treated is heated by directly passing it upward in the vertical direction through the gas flow path 6, which is formed by the adjacent spacing of electric heaters 4 and 5 that are closely adjacent to each other in the direction perpendicular to the gas flow direction. It is possible to thermally decompose the target gas and to trap the powder by-produced by the thermal decomposition.

Therefore, the thermal decomposition process can be performed only by the heater section 3 consisting of the planar electric heater 4 or the linear electric heater 5 without combustion, and safe detoxification process becomes possible. In addition, clean detoxification treatment is possible without using cleaning equipment such as a scrubber.

DESCRIPTION OF SYMBOLS 1... Thermal abatement device, 2... Chamber, 2a... Inner peripheral surface, 2b... Gas inlet, 2c... Gas outlet, 3... Heater part, 3a... Outer circumferential surface, 4... Planar electric heater, 5... Linear electric heater, 6... Gas passage, 6a... Starting point, 6b... End point, 7... Rectifying part, 7a... Discharge hole, 8... Preheater part, 9... Reflector, 9a... Lower end opening, 9b... Top opening, 10...net, C...cooler, P...pipe.

Claims (6)

A thermal abatement system that is equipped with a cylindrical chamber and a heater section that fits into the inner peripheral surface of the chamber, and performs abatement treatment by directly passing the gas to be treated vertically upward inside the heater section and heating it. In the device, the heater section is formed by molding a planar or linear electric heater into a spiral shape in plan view, and has a gas flow path that is spiral in plan view and is formed by adjacent intervals between the electric heaters. , a rectifying part that covers the upper part of the heater part, the rectifying part fitting into the inner circumferential surface of the chamber, and having a discharge hole in the center that allows the processed gas to pass through. type abatement device. 2. The thermal abatement device according to claim 1, wherein the planar electric heater has a large number of passing gas holes. 3. The thermal abatement device according to claim 1, further comprising a pressure sensor provided upstream of the heater section. A preheater section is provided upstream of the starting point of the gas passage in the heater section, and the preheater section comprises a truncated inverted conical reflector that covers the lower end of the heater section. The thermal abatement device according to any one of claims 1 to 3. 5. The thermal abatement device according to claim 4, wherein a net made of metal that functions as a catalyst in the abatement process is disposed at the lower end opening of the reflector. 6. A thermal detoxification method using the thermal detoxification device according to any one of claims 1 to 5, wherein the gas to be treated is passed directly upward in the vertical direction through the gas flow path of the heater section. A thermal abatement method characterized by thermally decomposing the gas to be treated and trapping powder by-produced by the thermal decomposition.

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