JP2016011759A - Exhaust gas combustion purification system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means capable of suppressing or preventing the crack, collapse, chipping or the like of a ceramic wall.SOLUTION: A combustion type purification device, with a ceramic wall 4' having air permeability on a side surface wall 4 of a combustion chamber 1, ejects oxygen-containing gas to the combustion chamber through the ceramic wall in order to prevent a solid particulate-like oxide from being accumulated on the side surface wall, and includes a spray nozzle 8 at a gas discharge port 7. In the combustion type purification device, the upper surface of the side surface wall of the combustion chamber is formed of the ceramic wall having air permeability, and the lower surface thereof is formed of a metal wall 4'' having air permeability.

Description

  The present invention relates to a combustion type purification apparatus for burning and removing harmful components contained in exhaust gas discharged from a semiconductor manufacturing process. More specifically, a combustion type purification device for converting harmful components discharged from a semiconductor manufacturing process into harmless substances or substances that can be easily detoxified by bringing them into contact with each other at high temperatures in the presence of flame and oxygen and burning them. It is about.

  With the development of the semiconductor industry in recent years, a great variety of gases have been used in the semiconductor manufacturing process. However, many of these gases are harmful to the human body and the environment, and it is essential to purify them before they are discharged outside the factory. The combustion purification method that decomposes these gases (hazardous components) by burning them is a convenient method that can be applied regardless of the composition and physical properties of the exhaust gas, especially in the case of high concentrations and large flow rates. It is more efficient than purification methods and wet purification methods.

  In the combustion purification method, exhaust gas containing harmful components, fuel gas such as propane, LPG, LNG, etc., air or oxygen, and inert gas as necessary are mixed in the combustion chamber and burned to harm the harmful components. The conversion to a simple oxide or a material that can be easily detoxified is performed. Conventional combustion purification apparatuses that have been used in the past introduce a combustion chamber for burning harmful components, and an oxygen-containing gas such as exhaust gas, fuel gas, air containing harmful components to be treated into the combustion chamber. Each pipe and nozzle for this, and the pipe | tube for discharging | emitting the gas after combustion from a combustion chamber, etc. are comprised. Further, a spray nozzle is provided near the gas discharge port of the combustion chamber to cool the exhaust gas at a high temperature by jetting cooling water.

  In the combustion type purification apparatus having such a configuration, harmful components are combusted and exhausted from the discharge port and released to the atmosphere or sent to the next processing apparatus. However, when the harmful component to be treated is a gas such as silane, phosphine, arsine, and diborane, solid particulate oxides (powder) of silicon, phosphorus, arsenic, and boron are generated by combustion, Most of them pass through the combustion chamber and are processed in the subsequent process, but some are deposited on the side wall in the combustion chamber, and the adhesion area and thickness increase with the passage of combustion time. As a result, uniform mixing of harmful components with fuel gas, air, oxygen, etc. is hindered and complete combustion is inhibited, resulting in a decrease in combustion temperature and a decomposition rate of harmful components to be treated. If the amount of powdered material accumulated is large, there was a risk of misfire.

Therefore, as in Patent Documents 1 to 5, the side surface of the combustion chamber is made of a breathable material made of ceramic, sintered metal, or the like, and a pressure gas flow path such as air or inert gas is provided on the outer periphery thereof, and the side wall A combustion type purifying apparatus has been developed that prevents the solid particulate oxide from accumulating on the side wall of the combustion chamber by ejecting the pressure gas into the combustion chamber via the gas.
JP 10-54534 A JP-A-10-61934 JP 2005-98680 A JP 2006-194544 A

  In the combustion type purifying apparatus as described above, when the side wall of the combustion chamber is made of a breathable ceramic, the side wall is superior to other materials such as metal in terms of heat resistance against flames and corrosion resistance against harmful components. be able to. However, ceramics have the disadvantage of being brittle, and cracks (cracks, cracks) occur due to the influence of flames, etc., and they may have an adverse effect on the combustion purification device itself and subsequent devices by collapsing or chipping. . Therefore, the problem to be solved by the present invention is a means for suppressing or preventing cracks, collapse, chipping, etc. of the side wall of the combustion chamber in the combustion purification device using breathable ceramic as the side wall of the combustion chamber. Is to provide.

  As a result of intensive studies to solve these problems, the present inventors have found that the ceramic wall is repeatedly affected by the high temperature caused by the flame and the low temperature caused by the cooling water ejected from the pre-nozzle for a long period of time. By replacing the lower surface of the side wall, which is particularly likely to come into contact with cooling water, from a breathable ceramic wall with a breathable metal wall, it is easy to cause collapse, chipping, etc. The inventors have found that cracks, collapse, chipping, and the like can be reduced without impairing the overall heat resistance, and have reached the combustion purification apparatus of the present invention.

  That is, the present invention relates to a combustion chamber for burning harmful components contained in exhaust gas discharged from a semiconductor manufacturing process, a nozzle for introducing flame into the combustion chamber, a nozzle for introducing exhaust gas into the combustion chamber, and a side wall of the combustion chamber Combustion-type purification provided with an oxygen-containing gas channel provided on the outer periphery of the side wall, an oxygen-containing gas inlet for introducing oxygen-containing gas into the channel, and a spray nozzle at the gas outlet after the combustion treatment An exhaust gas combustion purification apparatus, wherein the upper surface of the side wall of the combustion chamber is a breathable ceramic wall and the lower surface of the side wall of the combustion chamber is a breathable metal wall.

  In the exhaust gas combustion purification apparatus of the present invention, the upper surface of the side wall, which requires heat resistance, is composed of a breathable ceramic wall, but the lower surface of the side wall is made of ceramic having a weak point in crack resistance. Instead, since the metal wall is excellent in crack resistance, cracks, collapse, chipping, etc. can be suppressed or prevented without impairing the heat resistance of the side wall of the combustion chamber. As a result, the outflow of debris from the ceramic wall is suppressed or prevented, and adverse effects on the combustion purification device and the subsequent device can be suppressed or prevented. The present invention is particularly effective for a combustion type purification apparatus that requires gas cooling immediately after the combustion process in order to reduce the size of the apparatus.

  The present invention comprises a combustion chamber for burning harmful components contained in exhaust gas discharged from a semiconductor manufacturing process, a nozzle for introducing flame into the combustion chamber, a nozzle for introducing exhaust gas into the combustion chamber, a side wall of the combustion chamber, Combustion-type purification apparatus provided with an oxygen-containing gas channel provided on the outer periphery of the side wall, an oxygen-containing gas inlet for introducing an oxygen-containing gas into the channel, and a spray nozzle at the gas outlet after the combustion treatment Applies to

  As harmful components that can be treated by the exhaust gas combustion purification device of the present invention, arsenic, phosphine, silane, disilane, dichlorosilane, diborane, hydrogen selenide, germane and other hydride gases, boron trifluoride, boron trichloride, Acid gases such as silicon tetrafluoride, silicon tetrachloride, titanium tetrachloride, aluminum chloride, germanium tetrafluoride, tungsten hexafluoride, basic gases such as ammonia, monomethylamine, dimethylamine, trimethylamine, hydrazine, perfluorocarbon, Examples thereof include halogenated carbon such as hydrofluorocarbon. Moreover, propane gas, natural gas, etc. can be used as fuel gas. These gases are used together with an inert gas such as nitrogen as necessary.

Hereinafter, the exhaust gas combustion purification apparatus of the present invention will be described in detail with reference to FIGS. 1 to 6, but the present invention is not limited thereto.
FIG. 1 is a longitudinal sectional view showing an example of an exhaust gas combustion purification device of the present invention. 2 is a cross-sectional view taken along the line aa ′ in FIG. FIG. 3 is a longitudinal sectional configuration diagram showing an example other than FIG. 1 of the exhaust gas combustion purification apparatus of the present invention. 4 is a cross-sectional view taken along the line bb ′ in FIG. FIG. 5 is a partially enlarged cross-sectional view showing an example of a side wall of a combustion chamber of the exhaust gas combustion purification apparatus of the present invention. FIG. 6 is a longitudinal sectional view showing an example of a purification device in which a water tank and a scrubber facility are combined with the exhaust gas combustion purification device of the present invention.

  As shown in FIGS. 1 to 4, an exhaust gas combustion purification device of the present invention includes a combustion chamber 1 for burning harmful components contained in exhaust gas discharged from a semiconductor manufacturing process, and a nozzle for introducing flame into the combustion chamber. 2. Nozzle 3 for introducing exhaust gas into the combustion chamber, side wall 4 of the combustion chamber, oxygen-containing gas channel 5 provided on the outer periphery of the side wall, oxygen-containing gas for introducing oxygen-containing gas into the channel 5 A combustion type purification apparatus provided with a spray nozzle 8 at a gas inlet 6 and a gas outlet 7 after combustion treatment, wherein the upper surface of the side wall of the combustion chamber is a breathable ceramic wall 4 ′, This is an exhaust gas combustion type purification apparatus in which the lower surface of the side wall is a breathable metal wall 4 ″.

  In the combustion type purification apparatus for exhaust gas of the present invention, a cylindrical side wall 4 having air permeability and heat insulation is provided on the side surface of the combustion chamber 1, and the exhaust gas contacts the high temperature flame in the combustion chamber 1. In contact with an oxygen-containing gas such as air supplied from the wall 4, harmful components contained in the exhaust gas are burned (thermally decomposed). At that time, although a pulverized product is generated depending on the type of harmful component, the pulverized product is deposited on the surface of the side wall 4 by the flow of oxygen-containing gas (including air) as shown by arrows in FIGS. Can be prevented.

  In the exhaust gas combustion purification apparatus of the present invention, the upper surface of the side wall of the combustion chamber where heat resistance is required is constituted by a breathable ceramic wall, and the cause of cracks is caused by cooling water ejected from the spray nozzle. The lower surface of the side wall of the combustion chamber that is easily affected is made of a breathable metal wall. As the material of the ceramic wall, alumina, silica, titania or the like can be used. Moreover, as the material of the metal wall, carbon steel, chrome steel, molybdenum steel, manganese steel, nickel steel, stainless steel, etc. can be used, and among these, it is preferable to use stainless steel.

  In the exhaust gas combustion purifying apparatus of the present invention, as shown in FIG. 1, the entire upper portion of the side wall 4 of the combustion chamber is breathable ceramic wall 4 ', and the entire lower portion of the side wall 4 of the combustion chamber is breathable. In addition to a configuration in which the metal wall 4 ″ is formed, a configuration in which only the upper surface is the ceramic wall 4 ′ and only the lower surface is the metal wall 4 ″ (FIG. 3) can be employed. The height of the breathable metal wall 4 "constituting the lower surface of the side wall of the combustion chamber is usually 5-30% of the total height of the side wall 4 of the combustion chamber, preferably the height of the entire side wall 4 In the present invention, the side wall 4 of the combustion chamber is usually in the shape of a cylinder having a thickness of 0.2 to 50 mm, preferably in the shape of a cylinder having a thickness of 5 to 30 mm.

  In the present invention, as the form of the surface of the side wall 4 (4 ′ and 4 ″) of the combustion chamber, for example, a configuration as shown in FIG. 5 can be given. FIGS. The hole diameter (diameter) is usually 0.01 to 3.0 mm, preferably 0.02 to 1.0 mm, and the hole 9 is not limited to a circle. In such a case, the size of the holes is the size corresponding to the above-mentioned hole diameter, and the holes can be arranged regularly and vertically or randomly. Fig. 5 is a partially enlarged sectional view of a wall having a linear gap 10. The gap is usually 0.005 to 2.0 mm, preferably 0.01 to 1.0 mm. It is a partial expanded sectional view of the wall which has the window-shaped gap | interval 11, and the gap | interval is the case at the time of converting into a square The length of the side is usually 0.01 to 3.0 mm, preferably 0.02 to 1.0 mm, and the form of the surface of the side wall 4 of the combustion chamber is not limited to these, For example, in addition to these, forms such as a laminate in which fibrous ceramics or metals are laminated, a laminate in which a large number of particulate ceramics or metals are laminated, porous ceramics or porous metals having pores, etc. be able to.

  If the holes and gaps in the side wall 4 of the combustion chamber are larger than the above ranges, the flow of oxygen-containing gas to the combustion chamber 1 is biased, and there may be a portion where the gas flow rate is high and a portion where the gas flow rate is high. There is a possibility that the powdered material accumulates in the portion where the flow rate of the gas is small. Moreover, when smaller than the said range, there exists a possibility that a hole and a gap | block may be obstruct | occluded by powdered material etc. in a short time. Furthermore, the air-permeable portion of the side wall 4 of the combustion chamber is preferably configured so that the porosity or porosity is about 50 to 90% in any form. When the porosity or porosity is less than 50%, there is a possibility that the powdered material is deposited on the wall surface, and when the porosity or porosity exceeds 90%, the strength of the side wall may be lowered.

  In the exhaust gas combustion purification apparatus of the present invention, the oxygen-containing gas flow path 5 is usually provided over the entire outer periphery of the side wall 4 of the combustion chamber as described above. The width of the oxygen-containing gas channel 5 is usually 5 to 200 mm, preferably 10 to 100 mm. When processing harmful components, the temperature of the combustion chamber 1 becomes a high temperature of 500 to 1200 ° C. With such a configuration, the heat of the combustion chamber 1 can be prevented from diffusing to the outside. The outer wall of the oxygen-containing gas flow path 5 matches the shape of the side wall 4 of the combustion chamber and is usually cylindrical.

  In the present invention, the oxygen-containing gas introduction port 6 for introducing the oxygen-containing gas into the flow path 5 is configured so that the oxygen-containing gas introduced from the introduction port 6 swirls through the annular oxygen-containing gas flow path 5. Is set to the correct direction. The oxygen-containing gas inlet 6 is usually set so that the oxygen-containing gas can be introduced within an angle range of ± 30 degrees with respect to the tangential direction of the ring, preferably substantially in the tangential direction of the ring. With such a configuration, the oxygen-containing gas can be prevented from staying and drifting at any location in the flow path 5, and the oxygen-containing gas can be prevented from flowing at a uniform flow rate and temperature. It becomes possible to introduce to.

  Further, the oxygen-containing gas flow path 5 can be divided into a plurality of parts in the exhaust gas introduction direction (vertical direction in FIG. 1), and the flow rate of the oxygen-containing gas introduced into each flow path can be controlled. . In such a case, the swirling directions of the oxygen-containing gas may be set to be the same as each other or may be set to be opposite to each other. However, when the side wall is configured to be able to introduce the oxygen-containing gas into the combustion chamber 1 while maintaining the swirl direction in the flow path, the swirl directions of the oxygen-containing gas in the adjacent flow paths are opposite to each other. It is preferable to facilitate the mixing of the gas in the combustion chamber by setting as described above.

  In the exhaust gas combustion purifying apparatus of the present invention, the fuel and the oxygen-containing gas are mixed immediately before the combustion chamber 1 and burned. When the fuel is burned, the tip of the flame may or may not enter the combustion chamber 1. Further, as shown in FIG. 1, the nozzle 3 for introducing exhaust gas into the combustion chamber 1 is usually installed on the outer peripheral side of the nozzle 2 for introducing flame into the combustion chamber 1. In the present invention, in addition to the oxygen-containing gas flow path 5, a nozzle for introducing the oxygen-containing gas into the combustion chamber 1 can be provided around the nozzle 2 for introducing the flame into the combustion chamber 1.

  In the exhaust gas combustion purifying apparatus of the present invention, the gas after the combustion treatment is cooled by cooling water ejected from a spray nozzle 8 provided at the discharge port 7 as shown in FIGS. Or sent to the next processing step. At that time, the cooling water ejected from the spray nozzle 8 may come into contact with the lower surface of the side wall 4 of the combustion chamber. However, in the present invention, since the lower surface of the side wall 4 of the combustion chamber is made of a breathable metal wall, there is no risk of cracks and the like as in the case of a breathable ceramic wall.

  When the exhaust gas discharged from the semiconductor manufacturing process is combusted by the exhaust gas combustion purification device of the present invention and then sent to the next processing process, the present invention implements such a processing process. It is also possible to equip it with equipment to do this. The water tank 17 and scrubber equipment shown in FIG. 6 are provided for the exhaust gas treated by the exhaust gas combustion purification device of the present invention, for removing pulverized substances contained in the treated gas, and for newly generated harmful components (easily detoxified). Component), which is not essential equipment in the present invention, but it is preferable to provide these equipment. That is, in the present invention, it is preferable that the exhaust gas combustion type purification device is provided with a pulverized product removal unit and / or an acid gas removal unit on the discharge side of the combustion chamber 1.

For example, when a hydride such as arsine, phosphine, silane, or diborane is processed by the exhaust gas combustion purification device of the present invention, solid particulate oxides such as arsenic, phosphorus, silicon, and boron are generated by combustion. . In addition, when a halide such as boron trifluoride, boron trichloride, silicon tetrafluoride, silicon tetrachloride, or C ₂ F ₆ is treated, a new acidic gas such as hydrogen chloride or hydrogen fluoride (which is easily harmless) Component that can be converted into In the purification device of FIG. 6, the pulverized material can be removed mainly by watering from the spray nozzle 13 and trapping in the perforated plate 19. Moreover, it is preferable to incline the piping 16 between the combustion purification device for exhaust gas of the present invention and the scrubber equipment toward the scrubber equipment so that the pulverized material can be easily washed out to the water tank 17.

  When the purification apparatus as shown in FIG. 6 in which the equipment of the water tank 17 and the scrubber is combined with the exhaust gas combustion type purification apparatus of the present invention, acidic gases such as hydrogen chloride and hydrogen fluoride are mainly used as the filler 20. Can be removed. Further, the demister 21 can also remove moisture. In FIG. 6, 12 is a cooling pipe, 14 is a flow meter, 15 is a pump, 18 is a drain pipe, and 22 is a discharge port for discharging processed gas to the outside.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited by these.

[Example 1]
(Production of combustion type purification device)
Cylindrical combustion chamber 1 (height 500 mm, diameter 200 mm), nozzle 2 for introducing a flame into the combustion chamber 1, nozzle 3 for introducing exhaust gas into the combustion chamber 1, and side wall 4 of the combustion chamber 1 (thickness 15 mm) 1 and 2 having a spray nozzle 8 in the annular oxygen-containing gas flow path 5 (width 20 mm), the oxygen-containing gas inlet 6 and the outlet 7 for discharging the burned gas to the outside. A purification device was manufactured. The side wall 4 is composed of a breathable ceramic wall 4 ′ having a micropore corresponding to a diameter of 10 to 100 μm and a breathable metal wall 4 ″, and the height of the breathable metal wall 4 ″ is determined by the combustion chamber. It was 20% of the height of the entire side wall. Further, the spray nozzle 8 quickly cools the gas after the combustion treatment, so that the combustion purification device can be miniaturized, so that the sprayed cooling water does not come into contact with the ceramic wall 4 ′, and the breathable metal wall It installed in the position which touches the lower part of 4 ''.

  A water tank 17 having a length of 300 mm, a width of 300 mm, and a height of 300 mm is installed in the lower right portion of the combustion purification device manufactured as described above, and a porous plate 19 and polypropylene resin are mainly used in the upper part of the water tank 17. A scrubber having a filler 20 and a demister 21 was installed. In addition, the lower part of the combustion purification device and the water tank are connected by an inclined pipe, and the spray nozzle 13 is installed on the upper part of the filler 20, so that the cooling water in the water tank 17 circulates, the flow meter 14, the pump 15, etc. To complete the purification device as shown in FIG.

(Combustion treatment test of combustion type purifier)
After water was poured into the water tank until the depth reached 150 mm, the pump was operated to eject water from the spray nozzles 8 and 13. Further, propane (flow rate 15 L / min) and air (flow rate 440 L / min) are mixed and combusted and introduced from the nozzle into the combustion chamber 1, and air is introduced from the four oxygen-containing gas inlets to 37.5 L / min. Each was introduced into the combustion chamber 1 through the side wall at a flow rate of 150 L / min in total. Next, nitrogen gas (flow rate: 490 L / min) containing silane (flow rate: 10 L / min) as exhaust gas is introduced into the combustion chamber 1 from each of the four nozzles at a rate of 125 L / min for a total of 500 L / min. I did it. After the silane combustion treatment for 20 hours, the ceramic wall 4 ′ and the metal wall 4 ″ were taken out from the combustion purification device and the surface was inspected. However, cracks and the like could not be detected.

[Example 2]
(Production of purification equipment)
In the production of the combustion purification device of Example 1, the combustion purification device was produced in the same manner as in Example 1 except that the side wall 4 of the combustion chamber 1 was changed to the configuration shown in FIGS. . Further, a scrubber was installed in the same manner as in Example 1 to complete a purification device as shown in FIG. Using this apparatus, the combustion treatment test of the combustion purification apparatus was conducted in the same manner as in Example 1. As a result, cracks or the like could not be detected from the surfaces of the ceramic wall 4 ′ and the metal wall 4 ″.

  As described above, in the exhaust gas combustion purification apparatus of the present invention, as shown in the embodiment, the upper surface of the side wall of the combustion chamber is composed of the ceramic wall and the lower surface of the side wall of the combustion chamber is composed of the metal wall. Cracks and the like can be suppressed or prevented without impairing the heat resistance of the side wall of the combustion chamber.

Configuration diagram of a longitudinal section showing an example of an exhaust gas combustion purification device of the present invention A-a 'sectional view in FIG. Configuration diagram of a longitudinal section showing an example other than FIG. 1 of the exhaust gas combustion purification device of the present invention B-b 'sectional view in FIG. The partial expanded sectional view which shows the example of the side wall of the combustion type purification apparatus of the exhaust gas of this invention Configuration diagram of a longitudinal section showing an example of a purification device in which a water tank and a scrubber facility are combined with the exhaust gas combustion purification device of the present invention

DESCRIPTION OF SYMBOLS 1 Combustion chamber 2 Nozzle which introduces flame into combustion chamber 3 Nozzle which introduces exhaust gas into combustion chamber 4 Side wall 4 'Breathable ceramic wall 4 "Breathable metal wall 5 Oxygen-containing gas flow path 6 Oxygen-containing gas inlet 7 Discharge port 8 Spray nozzle 9 Hole 10 Linear gap 11 Lattice window-like gap 12 Cooling pipe 13 Spray nozzle 14 Flow meter 15 Pump 16 Pipe between exhaust gas combustion purifier and scrubber equipment 17 Water tank 18 Drain pipe 19 Porous Plate 20 Filler 21 Demister 22 Exhaust port for discharging treated gas to the outside

Claims (5)

  Combustion chamber for burning harmful components contained in exhaust gas discharged from a semiconductor manufacturing process, nozzle for introducing flame into the combustion chamber, nozzle for introducing exhaust gas into the combustion chamber, side wall of the combustion chamber, An oxygen-containing gas flow path provided on the outer periphery, an oxygen-containing gas introduction port for introducing an oxygen-containing gas into the flow path, and a combustion-type purification device provided with a spray nozzle at the gas discharge port after the combustion treatment, An exhaust gas combustion purification apparatus, wherein the upper surface of the side wall of the combustion chamber is a breathable ceramic wall, and the lower surface of the side wall of the combustion chamber is a breathable metal wall.   The combustion-type purification apparatus for exhaust gas according to claim 1, wherein the side wall of the combustion chamber has a cylindrical shape.   The exhaust gas combustion purification device according to claim 1, wherein the oxygen-containing gas flow path is annular.   2. The exhaust gas combustion purification apparatus according to claim 1, wherein the height of the breathable metal wall constituting the lower surface of the side wall of the combustion chamber is 5 to 30% of the total height of the side wall of the combustion chamber.   The exhaust gas combustion purification apparatus according to claim 1, wherein a dust removal unit and / or an acid gas removal unit is provided on the discharge side of the combustion chamber.

Images