JP2005291675A - Combustion type exhaust gas treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustion type exhaust gas treatment device of low manufacturing cost, capable of effectively preventing the accumulation of SiO<SB>2</SB>powder inside of a combustion cylinder, and reducing the air quantity without lowering a decomposition rate of PFC<SB>S</SB>and the like. <P>SOLUTION: This combustion type exhaust gas treatment device for decomposing harmful substances included in the exhaust gas by burning the same, comprises the combustion cylinder 4 of a double cylinder structure composed of an inner cylinder 2 connected with a combustion nozzle 5 and constituting a combustion part B for burning the exhaust gas, and an outer cylinder 3 mounted around the inner cylinder 2, and a number of air holes penetrated through a wall face are formed for taking the air into the whole area of a side wall face of the inner cylinder 2 of the combustion part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a combustion-type exhaust gas treatment apparatus that decomposes components having toxicity, combustion explosive properties, and environmental hazards discharged from semiconductor manufacturing equipment and the like and discharges them at a safe concentration.

2. Description of the Related Art As an exhaust gas treatment device in a semiconductor manufacturing process, a combustion type exhaust gas treatment device for treating exhaust gas by burning exhaust gas together with fuel gas is used. In recent years, in the semiconductor manufacturing process, the substrate size has been increased. Especially in the production of large TFT liquid crystal, the substrate size has increased several times over the past few years. The amount of semiconductor material gas used increases in proportion to the substrate size, and the amount of exhaust gas discharged also increases. Of the semiconductor material gas, for example, SiH ₄ generates SiO ₂ by combustion decomposition. When the amount of generated SiO ₂ increases, SiO ₂ powder accumulates in the exhaust gas treatment device, which hinders continuous operation of the exhaust gas treatment device. Therefore, the exhaust gas treatment device is required to take measures to prevent the deposition of SiO ₂ powder.

On the other hand, PFC _S used in chamber cleaning, etching equipment, etc. in the semiconductor manufacturing process (refers to 6 types of gases: CF ₄ , C ₂ F ₆ , C ₃ F ₈ , SF ₆ , NF ₃ , and CHF ₃ ) Is a component having a high global warming potential and a large impact on the environment. Exhaust gas treatment equipment used for this decomposition treatment is required to have a high decomposition rate from the viewpoint of preventing global warming and to have a more efficient energy utilization rate from the viewpoint of reducing CO ₂ emission. Is done.

Known as a combustion type exhaust gas treatment apparatus that prevents SiO ₂ powder from accumulating inside the combustion cylinder, an apparatus configured to introduce air in the flow direction of the combustion gas in the inner cylinder along the inner wall of the inner cylinder is known. (For example, see Patent Document 1). As shown in FIG. 10, the combustion exhaust gas treatment device described in Patent Document 1 is formed in a double structure including an inner cylinder 102 that becomes a combustion section B and an outer cylinder 103 that covers the periphery of the inner cylinder 102. Equipped with a combustion cylinder. A burner section 104 for burning the processing gas by burning the fuel gas is provided at the lower end of the inner cylinder 102, and a combustion nozzle connected to supply the exhaust gas into the inner cylinder 102 to the burner section 104 105 is attached, and an air supply port 106 for supplying secondary combustion air to the lower end of the burner unit 104 is provided. Furthermore, a cooling inner cylinder 107 as a cooling unit C is provided at the end of the combustion unit B.

  As shown in FIG. 10, the inner cylinder 102 of the combustion section B is configured in a multistage shape by combining a plurality of cylindrical members having different diameters. When the upper and lower cylindrical members are overlapped, the upper cylindrical member is overlapped so that the lower end of the upper cylindrical member covers the upper end of the lower cylindrical member, and the inner and lower cylinders of the overlapping portion of the upper cylindrical member are overlapped. A gap S is formed between the outer surfaces of the overlapping portions of the member. Air outside the inner cylinder 102 of the combustion section B flows through the gap S along the inner wall surface of the inner cylinder 102. Air flows in the same direction as the flow direction of the combustion gas.

  Although not specifically described in the literature, there is a combustion type exhaust gas treatment apparatus provided with a cooling unit that introduces spray water and cools the combustion gas at the end of the combustion unit having a cylindrical structure common to the above-described device. Are known. This spray water cooling type combustion exhaust gas treatment device can basically reduce the total flow rate of exhaust gas after combustion. As a result, the capacity of the scrubber for final processing is reduced, the amount of air introduced into the processing apparatus is reduced, and the amount of introduced outside air managed in a clean room or the like is reduced.

JP 11-270831 A

In recent years, the concentration of SiH _{4 in} the exhaust gas introduced into the exhaust gas treatment device has increased, and the amount of deposited SiO ₂ powder generated by combustion has also increased. Therefore, it is necessary to take measures against increasing the amount of SiO ₂ powder deposited in the combustion cylinder. For example, the concentration of SiH _{4 in} the exhaust gas was about 0.1 to 0.5% before, but has recently become 0.5 to 1% or more. Also, the amount of exhaust gas that is introduced into the combustion cylinder and processed is increasing.

In the conventional apparatus described in Patent Document 1, the amount of SiO ₂ powder deposited can be reduced by further increasing the amount of air that flows along the inner wall surface of the inner cylinder 102 and is introduced in the flow direction of the combustion gas. did it. However, in this method, since the combustion temperature in the combustion section decreases to increase the amount of air introduced into the inner cylinder, the temperature necessary for decomposing PFC _S such as NF ₃ cannot be maintained, and the decomposition rate Has the disadvantage of lowering.

  Further, the apparatus described in Patent Document 1 is assembled such that a plurality of members having different inner cylinder diameters are assembled in a multistage structure as an air introduction means, and a gap S is formed between the members. Producing a multi-stage shape by combining a plurality of cylindrical members in this way has a problem in that the cost of the member itself increases, and more precise production is required, resulting in an increase in manufacturing cost. .

  Further, in the case of a spray water cooling type combustion exhaust gas treatment device, the feature of this device is that the amount of air can be reduced, and further reduction of the amount of introduced air is a very important problem.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and can effectively prevent the accumulation of SiO ₂ powder inside the combustion cylinder and reduce the amount of air without reducing the decomposition rate of PFC _S or the like. It is an object of the present invention to provide a combustion exhaust gas treatment device that can be reduced and has a low manufacturing cost.

The present invention is (1) a combustion type exhaust gas treatment apparatus that burns and decomposes harmful substances contained in exhaust gas, and an inner cylinder that constitutes a combustion section connected to a combustion nozzle and combusts exhaust gas, and the inner cylinder A combustion cylinder having a double cylinder structure including an outer cylinder provided in the periphery is provided, and a large number of ventilation holes communicating with the wall surface for taking in air are provided in the entire side wall surface of the inner cylinder of the combustion section. Combustion type exhaust gas treatment device,
(2) The combustion exhaust gas treatment apparatus according to (1) above, wherein the inner cylinder of the combustion section has a large number of through-holes formed in the entire side wall surface of the cylindrical body.
(3) The combustion-type exhaust gas treatment apparatus according to (1), wherein the inner cylinder of the combustion section has a cylindrical side wall surface made of a porous body.
(4) The combustion-type exhaust gas treatment apparatus according to (1), wherein the inner cylinder of the combustion section is formed by forming a side wall surface of the cylindrical body from a net-like body,
(5) The diameter D [mm] of the cylinder of the inner cylinder of the combustion section, the average flow velocity V [m / s] of the combustion exhaust gas, the diameter d [mm] of the vent hole, and the average flow velocity v [m / of the air flowing from the vent hole s], the combustion portion is formed so that a numerical value αd obtained by multiplying the velocity ratio α = v / V of the combustion exhaust gas and the air flowing from the vent hole by the diameter d of the vent hole is 4 or less. The combustion type exhaust gas treatment device according to any one of (2) to (4) above,
Is a summary.

The combustion type exhaust gas treatment apparatus of the present invention employs a configuration in which a large number of air holes communicating from the outside to the inside of the wall surface are provided in the entire side wall surface of the inner cylinder of the combustion unit, thereby providing a plurality of conventional cylindrical shapes. Compared with a device having a combustion part composed of a combination of members, it is possible to effectively prevent the accumulation of SiO ₂ powder inside the combustion cylinder and to reduce the decomposition rate of NF ₃ without reducing the decomposition rate of NF ₃ The amount of air introduced into the inside can be reduced.

  Furthermore, since the device of the present invention has a simple structure as compared with the conventional device, the number of parts can be reduced, the device can be easily manufactured, and the cost of the device can be reduced.

The reason why the apparatus of the present invention can achieve the above-described effect over the conventional apparatus will be described below. In the above-described conventional apparatus, the air outside the combustion section flows in along the inner wall surface of the inner cylinder of the combustion section in the same direction as the flow direction of the combustion gas from the gap between the cylindrical members, thereby protecting the air. A film was formed, and this protective film prevented the SiO ₂ powder from adhering and depositing on the inner wall surface of the combustion part. This protective film is destroyed by turbulent mixing with the combustion gas inside the combustion section, and the SiO ₂ powder accumulation preventing effect cannot be obtained. Therefore, in the past, in order to increase the effect of preventing SiO ₂ powder accumulation, the amount of air flowing in from the wall surface of the inner cylinder was increased to reduce turbulent mixing with the combustion gas and to form a good protective film. It has been found that increasing the amount of air lowers the combustion temperature and lowers the decomposition rate.

On the other hand, the device according to the present invention is provided with a large number of vent holes communicating with the entire side wall surface of the inner cylinder of the combustion section, so that air is efficiently fed from the outside of the inner cylinder to the entire inner cylinder through the numerous vent holes. It is. The air sent into the inside from the entire side wall surface of the inner cylinder is rapidly mixed with the combustion gas inside the inner cylinder and formed as a protective film on the wall surface inside the inner cylinder, thereby preventing the deposition of SiO ₂ powder.

In conventional devices, the introduction of air is in the direction along the wall of the combustion cylinder. On the other hand, the device according to the present invention allows air to flow in from the entire area of the inner cylinder side wall surface of the combustion section in a direction intersecting the flow direction of the combustion gas. As a result, even if the amount of intake air flowing into the inner cylinder is reduced, it is possible to sufficiently prevent the SiO ₂ powder from being deposited.

  In the conventional apparatus, since air is introduced from the gap between the cylindrical members, the introduced air is heated at a portion that comes into contact with the wall surface after entering the combustion portion. Therefore, a temperature drop in the inner cylinder is inevitable. On the other hand, the apparatus of the present invention introduces external air into the inner cylinder from a large number of air holes in the entire area of the inner cylinder side wall surface of the combustion section. The air flowing into the combustion section is heated by heat transfer from the wall surface when passing through a large number of air holes in the wall surface. The area where the air flowing into the interior contacts with the wall surface when passing through the vent hole is much larger than the gap of the conventional apparatus and has a large heat capacity. As a result, the air flowing in from the wall surface is efficiently heat-exchanged and heated, so that the combustion temperature inside the inner cylinder does not decrease.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a conceptual diagram showing an example of the combustion exhaust gas treatment apparatus of the present invention. The combustion exhaust gas treatment apparatus shown in FIG. 1 includes a combustion cylinder 4 having a double cylinder structure including an inner cylinder 2 that becomes a combustion section B and an outer cylinder 3 that covers the periphery of the inner cylinder 2. A combustion nozzle 5 for combusting exhaust gas is connected to the inner cylinder 2 of the combustion section B. As shown in FIGS. 2 (a) and 2 (b), the inner cylinder 2 is formed of a cylindrical body, and a large number of vent holes communicating with the inside and outside of the wall surface are provided in the entire side wall surface 21.

  The outer shape of the inner cylinder 2 of the combustion part B is not particularly limited, but a cylindrical body is preferable because it is easy to manufacture and has good combustion efficiency. As shown in FIGS. 2 (a) and 2 (b), a large number of air holes communicating with the inside and outside of the wall surface are provided in the entire side wall surface 21 of the inner cylinder 2. The vent holes are formed in a substantially uniformly distributed state on the entire side wall surface 21 and penetrate the wall surface from the outside to the inside of the inner cylinder 2 of the combustion part, so that air is uniformly distributed from the entire side wall surface 21. It only needs to be able to pass.

  As a specific example of the inner cylinder 2 having a vent hole in the side wall surface 21, the inner cylinder 2 is composed of a porous body such as a sintered body of metal particles [see FIG. 2 (a)], and a plurality of wire meshes are laminated. The side wall surface is configured by winding it into a cylindrical shape (see FIG. 2 (b)), the side wall surface being formed by winding a metal plate with a large number of through holes in a cylindrical shape, For example, a metal cylinder is formed and a through hole is formed in the side wall surface by post-processing.

  FIG. 3 is a longitudinal sectional view of the inner cylinder 2. For example, as shown in FIG. 3, the vent hole 24 provided in the side wall surface 21 of the inner cylinder 2 is linearly side with respect to the flow direction P of the combustion exhaust gas in the horizontal direction perpendicular to the direction P. It is formed as a hole that penetrates the wall surface 21. The shape of the vent hole 24 may be formed at an angle or as a non-linear through hole, in addition to being linearly formed in the horizontal direction as shown in FIG. In this case, an even greater effect can be obtained by forming the angle from the outside of the side wall portion of the inner cylinder of the combustion section to be inclined in the flow direction of the combustion exhaust gas with respect to the inner side of the inner cylinder. Further, when the side wall surface of the inner cylinder is formed of a porous body, the vent hole does not penetrate the wall surface linearly, and a passage is formed in a random direction.

  The inner cylinder 2 has a ceiling surface 22 opened, and a combustion nozzle 5 is connected to the bottom surface 23. As shown in FIG. 3, the combustion nozzle 5 is provided at the approximate center of the bottom surface 23 of the inner cylinder 2 with the outlet of the nozzle 5 facing the inner cylinder 2. Further, around the nozzle 5 on the bottom surface 23 at the lower end portion of the inner cylinder 2, a secondary combustion air supply port 6 comprising a hole penetrating to the outside is provided. Also, as shown in FIG. 1, a plurality of cylindrical members are combined in the combustion gas outflow side end of the inner cylinder 2 of the combustion section B so that a gap is formed between the cylindrical members. A cooling inner cylinder 7 that functions as the cooling unit C is provided.

  As shown in FIG. 3, the diameter D [mm] of the cylindrical body of the inner cylinder 2 of the combustion section B, the average flow velocity V [m / s] of the combustion exhaust gas in the combustion section B, the diameter d [mm] of the vent hole 24, When the average flow velocity v [m / s] of the air flowing in from the pores is set, the numerical value αd obtained by multiplying the velocity ratio α = v / V of the combustion exhaust gas and the air flowing in from the ventilation holes by the diameter d of the ventilation holes is 4 or less. It is preferable to form the combustion part so that Specifically, in order to satisfy the above conditions, the diameter D of the cylindrical body of the inner cylinder 2, the diameter d of the vent hole 24, the ratio to the area of the side wall surface of the vent hole 24, etc. may be selected according to the operating conditions. Good.

  A fuel gas supply path and an exhaust gas supply path are connected to the inlet side 5a of the combustion nozzle 5 of the apparatus shown in FIG. 1 (not shown in particular). Fuel such as fuel gas is supplied from the fuel gas supply path. From the exhaust gas supply path, exhaust gas as a component to be removed including harmful substances such as semiconductor manufacturing raw material gas is supplied. By burning the fuel gas near the tip of the combustion nozzle 5, harmful components in the exhaust gas are burned and decomposed.

  Although air is previously mixed in the fuel gas, it is necessary to supply air from the outside of the flame in order to efficiently burn the components to be removed in the exhaust gas. Such air is supplied from a secondary combustion air supply port 6 provided at the lower end of the inner cylinder 2. By adjusting the hole diameter of the secondary combustion air supply port 6, it is possible to adjust the air supply amount so that optimum combustion can be performed.

Exhaust gas targeted by the device of the present invention includes exhaust gas containing flammable components and toxic components, or exhaust gas containing components that need to be removed or reduced in concentration when discharged into the atmosphere from the viewpoint of environmental protection. For example, it is a gas discharged in various processes when manufacturing a semiconductor. Specifically, a gas containing SiH ₄ , SiH ₂ Cl ₂ , GeH ₄ , B ₂ H ₆ , AsH ₃ , PH ₃ , NF ₃ , C ₂ F _{6 and the} like can be given.

  The fuel gas supplied to the combustion nozzle is mainly hydrogen, methane, propane, butane, ethylene, natural gas, or a mixed gas thereof, and air or oxygen-enriched air as necessary. Or the like as a combustion gas is used.

  FIG. 4 is a conceptual diagram of the sprayed water cooling type combustion exhaust gas treatment apparatus of the present invention. In the case of the spray water cooling type apparatus, the cooling section C connected to the end of the combustion section B may be formed as a water cooling type as shown in FIG. In the combustion exhaust gas treatment apparatus 1 shown in FIG. 4, a cooling cylinder 9 in which a water sprayer 8 constituting a cooling part C is connected to a combustion cylinder 4 constituting a combustion part B consisting of an inner cylinder 2 and an outer cylinder 3. Has been. The combustion nozzle 5 is connected to the burner portion 10 at the upper end of the inner cylinder 2 from the upper end of the outer cylinder 3 of the combustion portion B. An air supply port 11 is provided above the side surface of the outer cylinder 3 of the combustion unit B, and an exhaust port 12 is provided below the side surface of the cooling cylinder 9 of the cooling unit C.

  In the combustion exhaust gas treatment apparatus 1 shown in FIG. 4, a vent hole that communicates the wall surface is provided over the entire side wall surface of the inner cylinder 2. A burner portion 10 is provided on the ceiling surface side of the inner cylinder 2, and the bottom surface side is open. Compared with the inner cylinder used in the type of cooling apparatus shown in FIG. 1, the upper and lower positional relationship is used in an opposite state, but the structure of the basic side wall and the like is the same. In the apparatus 1 shown in FIG. 4, the exhaust gas introduced together with the fuel gas from the upper part of the apparatus 1 is combusted in the inner cylinder 2 together with the air supplied from the air supply port 11 or the like in the combustion part B. The combustion gas is cooled by the water sprayed from the water sprayer 8 provided in the cooling unit, and is discharged from the exhaust port 12.

Examples of the present invention and comparative examples are shown below.
Comparative Example 1
With the structure shown in FIG. 10, SiH ₄ 0.25 l / min and N ₂ 50 l / min are treated as a standard exhaust gas load condition, and SiH ₄ 2 l / min, when 1 hour combustion treatment of exhaust gas of N ₂ 200 l / min, by changing the amount of intake air introduced into the apparatus 4m ³ /min,6.5m ³ / min, and 10 m ³ / min, The weight of the SiO ₂ powder deposited on the inner cylinder was measured. The results are shown in FIG. 5 together with the results of treating exhaust gas of SiH ₄ 0.25 l / min and N ₂ 50 l / min. As shown in FIG. 5, as the amount of intake air increases, the flow rate of air introduced into the combustion section of the inner cylinder also increases, so the amount of SiO ₂ powder deposited due to the combustion decomposition of SiH ₄ also decreases.

Furthermore, Fig. 6 shows the results of measuring the residual ratio of NF ₃ when operating the system under the same combustion conditions as above except that NF ₃ was supplied at 1 l / min as exhaust gas and the amount of diluted N ₂ was changed. Show. As shown in FIG. 6, the residual ratio of NF ₃ increases as the intake air amount increases. That is, this experimental result indicates that the decomposition rate of NF ₃ decreases in the conventional apparatus when the intake air amount is increased.

Example 1
The apparatus of Example 1 was configured with the combustor part (inner cylinder) of the apparatus of Comparative Example 1 provided with a plurality of through holes formed in the entire cylindrical wall surface shown in FIG. The exhaust gas load conditions were SiH ₄ 2 l / min and N ₂ 200 l / min as in Comparative Example 1, and the SiO ₂ powder deposited on the inner cylinder when the intake air amount was changed from ⁴ to 10 m ³ / min. The weight was measured. The results are shown in FIG. As shown in FIG. 7, in the case of Comparative Example 1, the weight of the SiO ₂ powder deposit increases as the amount of intake air decreases, but in the case of Example 1, the weight of the SiO ₂ powder deposit increases even if the amount of intake air decreases. The effect of the device of the present invention can be understood.

Using the device of Example 1, the intake air amount was 4 m ³ / min, NF ₃ was supplied as exhaust gas at 1 l / min, the dilution N ₂ amount was changed, and the device was operated under the same combustion conditions as above. The residual ratio of NF ₃ when operating was measured. The results are shown in FIG. Referring to FIG. 8, the residual ratio of NF ₃ in the apparatus of Example 1 was not higher than the residual ratio of the apparatus in Comparative Example 1, and no difference in decomposition performance was observed. That the graph of FIG. 8, it is device of Example 1, without reducing the performance of decomposing NF _3, while maintaining the performance of decomposing good NF _3, it is possible to prevent the SiO ₂ powder deposition I understand.

[Experimental example]
In the apparatus of Example 1, those in which the diameter of the through hole of the inner cylinder was changed to 0.5 to 1 mm were prepared, and in the case of using each inner cylinder, the load condition of the exhaust gas was changed to SiH ₄ as in Comparative Example 1. The weight of SiO ₂ powder deposited on the inner cylinder was measured when the air intake amount was changed from ³ to 10 m ³ / min at 2 l / min and N ₂ 200 l / min. The diameter D [mm] of the cylinder of the combustion section inner cylinder, the average flow velocity V [m / s] of the combustion exhaust gas, the diameter d [mm] of the vent hole, and the average flow velocity v [m / s] of the air flowing from the vent hole In this case, a graph showing a relationship between a numerical value αd obtained by multiplying the velocity ratio α = v / V of combustion exhaust gas and air flowing in from the vent hole by the diameter d of the vent hole and the weight of the SiO ₂ powder deposited on the inner cylinder. It is shown in FIG. From this graph, when the value of αd exceeds 4, the deposited weight of the SiO ₂ powder increases. It can be seen that when the value of αd is 4 or less, the deposition preventing effect of the SiO ₂ powder can be stably obtained.

It is a conceptual diagram which shows an example of this invention combustion type exhaust gas processing apparatus. (a), (b) is an external appearance perspective view which shows the aspect of an inner cylinder. FIG. 2 is a longitudinal sectional view of the inner cylinder in FIG. It is a conceptual diagram which shows the other example of this invention combustion type exhaust gas processing apparatus. 6 is a graph showing the relationship between the intake air amount and the SiO ₂ deposition amount of the combustion exhaust gas treatment apparatus of Comparative Example 1. 4 is a graph showing the relationship between the diluted N ₂ flow rate and the NF ₃ residual rate of the combustion exhaust gas treatment apparatus of Comparative Example 1. 3 is a graph showing the relationship between the intake air amount and the SiO ₂ deposition amount of the combustion exhaust gas treatment apparatus of Example 1. ₃ is a graph showing the relationship between the diluted N ₂ flow rate and the NF ₃ residual rate of the combustion exhaust gas treatment apparatus of Example 1. It is a graph showing the relationship between the value of the SiO ₂ deposition amount and αd experimental examples. It is a conceptual diagram which shows the conventional combustion type exhaust gas processing apparatus.

Explanation of symbols

1 Combustion exhaust gas treatment system
2 Inner cylinder
3 outer cylinder
4 Combustion cylinder
5 Combustion nozzle
6 Secondary combustion air supply port
21 Side wall of inner cylinder
B Combustion section
C Cooling unit
P Combustion gas flow direction

Claims (5)

  In a combustion-type exhaust gas treatment apparatus that burns and decomposes harmful substances contained in exhaust gas, an inner cylinder that constitutes a combustion unit to which a combustion nozzle is connected and burns the exhaust gas, and an outer cylinder that is provided around the inner cylinder Combustion-type exhaust gas characterized in that a plurality of vent holes communicating with the wall surface for taking in air are provided in the entire side wall surface of the inner cylinder of the combustion section. Processing equipment.   2. The combustion-type exhaust gas treatment apparatus according to claim 1, wherein the inner cylinder of the combustion section has a large number of through holes formed in the entire side wall surface of the cylindrical body.   2. The combustion-type exhaust gas treatment apparatus according to claim 1, wherein the inner cylinder of the combustion section has a cylindrical side wall surface made of a porous body.   2. The combustion type exhaust gas treatment apparatus according to claim 1, wherein the inner cylinder of the combustion section is formed by forming a side wall surface of the cylindrical body from a net-like body. The diameter D [mm] of the cylinder of the combustion section inner cylinder, the average flow velocity V [m / s] of the combustion exhaust gas, the diameter d [mm] of the vent hole, and the average flow velocity v [m / s] of the air flowing from the vent hole In this case, the combustion part is formed so that a numerical value αd obtained by multiplying the velocity ratio α = v / V of the combustion exhaust gas and the air flowing in from the vent hole by the diameter d of the vent hole is 4 or less. The combustion type exhaust gas treatment apparatus according to any one of?

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