JP2008032310A - Combustion detoxifying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve detoxifying efficiency and to reduce operation costs. <P>SOLUTION: In this combustion detoxifying device 1 comprising a cylindrical combustion chamber 3 of which one end is defined by a combustion chamber end wall 5 and of which the circumference is defined by a peripheral wall 3a, the end wall 5 is provided with a waste gas introduction port 7 and plural burners 9, each burner 9 is provided with a fuel injector 11 and an air swirler 13, each air swirler 13 forms swirl flow d of the air in the uniform direction in the combustion chamber 3, and the combined swirl flow D can be formed as a whole around a central shaft 3c of the combustion chamber 3 in the combustion chamber 3 by interference of the swirl flows d with each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a combustion abatement apparatus that decomposes waste gas such as chlorofluorocarbon gas generated in the manufacturing process of semiconductors and liquid crystal displays by burning it with high-temperature combustion gas and converts it into CO ₂ , Cl ₂ , SiO _2, etc. In particular, it is an apparatus suitable for the combustion detoxification of CF ₄ or the like that is difficult to decompose unless it is at a high temperature, but can also be used for detoxification of other harmful gases and harmful substances such as PCB.

Waste gases such as silane (SiH ₄ ) and disilane (Si ₂ H ₆ ) are generated from semiconductor manufacturing equipment and liquid crystal panel manufacturing equipment. However, since this waste gas is harmful, it can be released into the atmosphere as it is. Can not. Therefore, conventionally, the waste gas has been detoxified using a combustion abatement apparatus.

  A conventional combustion abatement apparatus includes a cylindrical burner portion whose upper end surface is closed, and a combustion chamber provided on the downstream side of the burner portion, and forms a combustion flame from the burner portion toward the combustion chamber, Waste gas is introduced into the combustion flame to oxidatively decompose the waste gas (see, for example, Patent Document 1).

  An air nozzle, an auxiliary combustion nozzle, and a waste gas introduction pipe are provided on the top wall of the burner part of the combustion abatement device, and the air nozzle ejects air so as to form a swirling flow in the burner part, and The auxiliary combustion nozzle ejects auxiliary combustion gas so as to form a swirling flow in the burner portion.

  The air nozzle promotes ignition of the auxiliary combustion gas ejected from the auxiliary combustion nozzle, and blows swirling air downward on the combustion flame formed downward of the opening. Further, the waste gas introduction pipe ejects waste gas into the burner part, and this waste gas burns while being mixed with the swirling flow of auxiliary combustion gas.

WO00 / 32990 International Publication

  In the conventional combustion abatement apparatus, air and fuel are not sufficiently mixed, and mixing of waste gas and high-temperature combustion gas is insufficient. For this reason, it is not possible to obtain a suitable detoxification efficiency, and fuel is wasted, resulting in an increase in operating cost.

  In view of the above circumstances, an object of the present invention is to improve the removal efficiency and reduce the operating cost.

  The present invention relates to a combustion abatement apparatus provided with a cylindrical combustion chamber having one end defined by a combustion chamber end wall and a periphery defined by a peripheral wall; the end wall includes a waste gas inlet and a plurality of burners Each of the burners is provided with fuel injection means and air swirling means, and each air swirling means forms a swirling flow of air in the same direction in the combustion chamber. A combined swirl around the central axis of the combustion chamber can be formed in the combustion chamber as a whole by mutual interference of flows.

  An air passage communicating with the air swirling means is provided in an outer peripheral portion of the peripheral wall of the combustion chamber, and air is circulated through the air passage to cool the peripheral wall of the combustion chamber and preheat the air. It is characterized by doing so.

  The burner is provided with oxygen injection means. A waste gas pipe is connected to the waste gas inlet, and a fuel addition pipe is connected to the waste gas pipe so that fuel can be added before the waste gas flows into the combustion chamber. It is characterized by that.

  A plurality of the introduction ports for the waste gas are provided. A waste gas swirling means is provided at the waste gas introduction port. The waste gas swirling means forms a swirling flow in a direction opposite to the swirling flow formed by the air swirling means.

  A heat-resistant protective cover is replaceably disposed inside the peripheral wall of the combustion chamber.

  In the present invention, a waste gas inlet and a plurality of burners are arranged on the end wall of the combustion chamber, and each of the burners is provided with a fuel injection means and an air swirling means, and each of the air The swirling means forms a swirling flow of air in the same direction in the combustion chamber, and a combined swirling flow around the central axis of the combustion chamber can be formed in the combustion chamber as a whole by mutual interference of the swirling flow. Since it is disposed, the air and the fuel are sufficiently mixed, and the mixing of the waste gas and the high-temperature combustion gas is promoted. As a result, the abatement efficiency can be dramatically improved, fuel and additional oxygen are not wasted, and the operating cost can be reduced after all.

Since the synthetic swirl of this invention swirls while contacting the combustion chamber wall, it is possible to prevent SiO ₂ powder or the like generated by combustion of waste gas from accumulating on the inner wall.

  An air passage communicating with the air swirling means is provided on the outer peripheral portion of the peripheral wall of the combustion chamber of the present invention, and air is circulated through the air passage, so that the peripheral wall of the combustion chamber is cooled and preheated. can do.

  Since the center axis of the air swirling means of the present invention is inclined at a predetermined angle with the center axis of the combustion chamber, the swirling flow around the center axis of the air swirling means interferes with each other and is entirely As a result, a combined swirl around the central axis of the combustion chamber can be formed in the combustion chamber.

  Since the burner according to the present invention is provided with oxygen injection means, the air released from the burner can be brought into an oxygen-enriched (oxygen-rich) state. Therefore, the combustion gas temperature can be increased and a high decomposition rate can be achieved even with a hardly decomposed gas.

  A waste gas pipe is connected to the waste gas inlet of the present invention, a fuel addition pipe is connected to the waste gas pipe, and fuel is added before the waste gas flows into the combustion chamber. Since it was made possible, a reducing reaction atmosphere can be formed.

  Since a plurality of waste gas inlets according to the present invention are provided, different types of waste gas can be supplied to each inlet, and a plurality of waste gas inlets can be connected.

  Since waste gas swirling means is provided at the waste gas inlet of the present invention, the waste gas can be dispersed. Therefore, the waste gas can be easily mixed and burned.

  The waste gas swirling means of the present invention forms a swirling flow in a direction opposite to the swirling flow formed by the air swirling means, so that the waste gas is swirled around the central axis of the air swirling means in the combustion chamber. , And the resultant swirl flow around the central axis of the combustion chamber. Therefore, the removal efficiency can be improved.

  Since the heat-resistant protective cover is replaceably disposed inside the peripheral wall of the combustion chamber of the present invention, the peripheral wall can be protected and maintenance of the heat-resistant protective cover can be easily performed. .

A first embodiment of the present invention will be described with reference to FIGS.
The combustion chamber 3 of the combustion abatement apparatus 1 is formed in a cylindrical shape, one end of which is closed by the end wall 5 and the other end is opened. The end wall 5 is provided with a waste gas inlet 7 and a plurality of burners 9. The tip of the burner 9 protrudes from the inner surface of the end wall 5, and the amount of protrusion is appropriately selected as necessary. For example, the protrusion amount may be set to zero, and the tip of the burner 9 may be flush with the inner surface of the end wall 5.

  The introduction port 7 is provided at the center of the end wall 5, and the central axis 5 c thereof is located on the central axis 3 c of the combustion chamber 3. The position of the central axis 5c is appropriately selected as necessary, and does not necessarily coincide with the central axis 3c.

  Four burners 9 are arranged so as to surround the introduction port 7, and four burners 9 are provided at equal intervals in the circumferential direction. The burner 9 includes fuel injection means and air swirl means.

  As the fuel injection means, for example, a fuel injector 11 having a nozzle 10 is used. As the air swirling means, for example, an air swirler 13 is used. The air swirler 13 is provided with a cylindrical air pipe 13a communicating with the air supply means. The nozzle 10 is concentrically built in the air pipe 13a, and a swirl vane 13b is provided at the tip of the air pipe 13a. The swirl vane 13b is provided at the tip of the air tube 13a or at a position slightly retracted from the tip, but this position can be appropriately selected as necessary.

  The central axis 11 c of the burner 9 is inclined at a predetermined angle θ with respect to the central axis 3 c of the combustion chamber 3. The inclination angle θ is selected as necessary, but is appropriately selected within a range of 30 degrees to 60 degrees, for example.

  A heat-resistant protective cover 16 is provided on the inner surface of the peripheral wall 3 a of the combustion chamber 3. The protective cover 16 is made of a heat-resistant material, for example, a ceramic material, and is detachably attached to the peripheral wall 3a of the combustion chamber 3.

Next, the operation of the present embodiment will be described.
When the air A is pumped to the air chamber 13a of the air swirler 13, the air A passes through the swirl vanes 13b and becomes a swirl flow d, and is discharged into the combustion chamber 3. The swirling flow d formed by the air swirlers 13 is a swirling flow d around the central axis 9c of the burner 9, and swirls in the same direction, for example, clockwise.

The air A is used as an oxidant for burning the fuel G. As the fuel G, for example, natural gas, propane, hydrogen, or the like is used.
In addition, since the air A and the fuel G are mixed after being jetted into the combustion chamber 3, the flashback phenomenon does not occur unlike the method (premixing method) in which the air A and the fuel G are discharged into the combustion chamber in a state where both are mixed in advance. Therefore, it is safe because the occurrence of a fuel flammable explosion accident can be prevented.

When the swirling flow d of the air A is mixed with the fuel G, the fuel G burns and proceeds obliquely downward toward the central axis 3c of the combustion chamber 3 while forming a swirling flame.
At this time, the waste gas H is pumped into the combustion chamber 3 from the waste gas introduction port 7, and as this waste gas H, for example, silane (SiH ₄ ) or disilane ( Hazardous combustible gas H such as SiH ₆ ) is used. The waste gas H is caught in the swirling flow d and burns while being dispersed.

The swirling flows (swirl flames) d rotate in the same direction and proceed obliquely downward toward the central axis 3c and interfere with each other, and as a whole swirl flows (swirl flames) around the central axis 3c. ) D. This swirl flow D will be referred to as a synthetic swirl flow (synthetic swirl flame). The synthetic swirl flow D combusts the waste gas H and swirls while rubbing the inner surface (heat-resistant protective cover 16) of the peripheral wall 3a, so that silica (SiO ₂ ) and the like produced by the combustion adhere to the inner surface. Accumulation can be prevented.

  In addition, since the heat-resistant protective cover 16 is detachably provided in the combustion chamber 3, it can be easily detached and replaced with a new one during maintenance.

A second embodiment of the present invention will be described with reference to FIGS. 3 and 4. The same reference numerals as those in FIGS. 1 and 2 have the same names and functions.
The difference between this embodiment and the first embodiment is that an air passage 28 surrounding the combustion chamber is used as the air tube of the air swirler instead of being arranged coaxially with the fuel injector. is there. That is, in this embodiment, the air passage 28 is provided on the outer periphery of the peripheral wall 3 a of the combustion chamber 3.

  The air passage 28 includes a vertical passage portion 28a and an inclined passage portion 28b continuous with the upper end portion of the vertical passage 28a. A pair of air supply ports 30 are arranged point-symmetrically at the lower part of the vertical passage portion 28a, and swirl vanes 13b are provided in the inclined passage portion 28b.

  In this embodiment, the air A pumped from the air supply port 30 of the burner 9A ascends in the vertical passage portion 28a and reaches the inclined passage portion 28b, and then burns while turning into a swirl flow through the swirl vanes 13b. It is discharged into the chamber 3. Therefore, since the peripheral wall 3a of the combustion chamber 3 is cooled, the peripheral wall 3a can be prevented from being damaged by heat. Further, since the air A is preheated while passing through the air passage 28, heat loss in the combustion chamber can be reduced as compared with the case where air at room temperature is blown into the combustion chamber.

  In this embodiment, six burners 9 are provided, the tips of the burners 9 are formed flush with the inner surface of the end wall 5, and the heat-resistant protective cover is omitted.

A third embodiment of the present invention will be described with reference to FIGS. 5 to 7. The same reference numerals as those in FIGS. 3 and 4 have the same names and functions.
The difference between this embodiment and the second embodiment (FIGS. 3 and 4) is as follows.
(1) The oxygen injection means is provided in the burner 9B.
As the oxygen injection means, for example, an oxygen injector 22 is used. The oxygen injector 22 includes a tube portion 22a that surrounds the fuel injector 11, and an inlet 22b provided in the tube portion 22a. It is equipped with.

(2) A plurality of waste gas inlets are provided.
Among the inlets, the waste gas pipe 8 connected to the central inlet 7A is provided with a waste gas swirling means, and a swirl flow forming nozzle 24 is used as the swirling means. The nozzle 24 is provided in a direction substantially tangential to the inner circumferential circle of the tubular body 8. The upper end of the tubular body 8 is closed by a lid 25.

  Three other inlets 7B are provided at equal intervals in the circumferential direction, and a fuel addition pipe 26 is connected to the waste gas pipe 8a connected to the inlet 7B.

  (3) Only one air supply port 30 is provided and there are three burners 9B.

  In this embodiment, since oxygen S is injected from the oxygen ejector 22, oxygen S is added to the air A. Therefore, since the swirling flow d of air is in an oxygen-enriched state, when the fuel G is injected here, the temperature of the combustion gas rises, and a high decomposition rate can be achieved even with a hardly decomposable gas.

  When the waste gas H is pumped to the swirl flow forming nozzle 24, the waste gas H enters the combustion chamber 3 while swirling around the central axis of the introduction port 7A, and is mixed with the swirl flow d of air. At this time, if the swirling flow Hd of the waste gas is swirled in the opposite direction (counterclockwise) to the swirling flow d of the air, the mixing can be efficiently performed.

When the waste gas H1 is supplied to the waste gas pipe 8a of the introduction port 7B and the fuel G is supplied to the fuel addition pipe 26, the waste gas H1 is mixed with the fuel G in the combustion chamber 3. Released. Then, a reducing reaction atmosphere can be formed. Although the different types of waste gas H and H ₁ supplied to the introduction port 7A and the introduction port 7B are used, it is needless to say that the same type of waste gas may be used.

The fourth embodiment of the present invention will be described with reference to FIGS. 8 and 9. The same reference numerals as those in FIGS. 5 to 7 have the same names and functions.
The differences between this embodiment and the third embodiment (FIGS. 5 to 7) are as follows.
(1) Although a plurality of waste gas inlets are provided, a fuel addition pipe 32 is provided in the waste gas pipe 8 of the central inlet 7C, and a swirl vane 13c is provided at the lower end of the pipe 8. It has been. Further, a swirl vane 13d is also provided at the lower end of the waste gas pipe 8a of the other inlet 7D.
(2) A cooling air supply pipe 34 is connected to the lower end of the combustion chamber 3 to form a cooling part 36, and this combustion abatement device is not shown through the cooling part 36 and is not shown in the figure. It was connected to.

  In this embodiment, the waste gas H pumped to the waste gas pipe 8 at the introduction port 7C is mixed with the fuel G supplied from the fuel addition pipe 32, and then passes through the swirl vane 13c and the swirl flow Hd. And released into the combustion chamber 3.

  Further, the waste gas H1 flowing through the waste gas pipe body 8a of the introduction port 7D passes through the swirl vane 13d while being mixed with the fuel G supplied from the fuel addition pipe 26 to become a swirl flow H1d.

  The waste gas swirl flows Hd and H1d are mixed with the swirl flow d formed by the burner 9B. When the former swirl direction is opposite to the latter swirl direction (counterclockwise), the waste gas swirl flows Hd and H1d are mixed efficiently. be able to.

When the cooling air A1 is pumped to the cooling air supply pipe 34, the cooling air A1 enters the lower end side of the combustion chamber 3 and cools the high-temperature combustion gas. At this time, the CO that has been separated due to the high temperature is recombined and returned to CO ₂ . The gas cooled by the cooling air A1 is sent to a water scrubber (wet abatement apparatus) together with CO _{2 and the} like.

It is a longitudinal section showing a 1st embodiment of the present invention. It is a bottom view of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of this invention. It is the IV-IV sectional view taken on the line of FIG. It is a figure which shows 3rd Embodiment of this invention, and is the VV sectional view of FIG. It is a longitudinal cross-sectional view which shows 3rd Embodiment of this invention. It is the VII-VII sectional view taken on the line of FIG. It is a longitudinal cross-sectional view which shows 4th Embodiment of this invention. It is the XX sectional view taken on the line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Combustion removal apparatus 3 Combustion chamber 3a Perimeter wall 3c Central axis 5 End wall 7 Waste gas inlet 8 Waste gas pipe body 9 Burner 9c Central axis
11 Fuel injector
13 Air swirler
16 Heat-resistant protective cover
22 Oxygen ejector
24 Swirling flow forming nozzle
26 Fuel addition pipe
28 Air passage
36 Cooling part A Air d Swirl D Synthetic swirl G Fuel H Waste gas

Claims (10)

A combustion abatement apparatus comprising a cylindrical combustion chamber having one end defined by a combustion chamber end wall and a periphery defined by a peripheral wall;
The end wall is provided with a waste gas inlet and a plurality of burners,
Each burner is provided with fuel injection means and air swirling means,
Each of the air swirling means forms a swirling flow of air in the same direction in the combustion chamber, and a combined swirling flow around the central axis of the combustion chamber is formed in the combustion chamber as a whole by mutual interference of the swirling flow. Combustion abatement apparatus characterized by being arranged so as to be able to.   An air passage communicating with the air swirling means is provided in the outer peripheral portion of the peripheral wall of the combustion chamber, and air is circulated through the air passage to cool the peripheral wall of the combustion chamber and preheat the air. The combustion abatement apparatus according to claim 1, wherein   The combustion abatement apparatus according to claim 1 or 2, wherein the air swirl means has a central axis inclined at a predetermined angle with a central axis of the combustion chamber.   The combustion abatement apparatus according to claim 3, wherein the predetermined angle is 30 ° to 60 °.   The combustion abatement apparatus according to claim 1, 2, 3, or 4, wherein the burner is provided with oxygen injection means.   A waste gas supply pipe is connected to the waste gas introduction port, and a fuel pipe is connected to the waste gas supply pipe so that the fuel can be added before the waste gas flows into the combustion chamber. The combustion abatement apparatus according to claim 1, 2, 3, 4, or 5.   The combustion abatement apparatus according to claim 1, wherein a plurality of the introduction ports for the waste gas are provided.   8. The combustion abatement apparatus according to claim 1, wherein a waste gas swirling means is provided at the waste gas introduction port.   The combustion abatement apparatus according to claim 8, wherein the waste gas swirling means forms a swirling flow in a direction opposite to the air swirling means.   10. The heat-resistant protective cover is disposed inside the peripheral wall of the combustion chamber so as to be replaceable. Combustion abatement device.

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