JP2017089986A - Exhaust gas treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas treatment device capable of stably detecting flame by an inexpensive method without using a UV sensor and a thermo couple using a photoelectron multiplier, by applying a method of detecting flame over water of wet wall from an outer side of a combustion chamber by utilizing the water of wet wall of heat-insulating mixed combustion method and the like.SOLUTION: An exhaust gas treatment device includes a combustion chamber 1 having the cylindrical container-shape closed at one end and opened at the other end and burning process gas, a water supply nozzle 5 disposed on an upper wall surface of the combustion chamber 1 and forming a water film on an inner peripheral face of the combustion chamber 1, and a flame detector 6 disposed on a wall surface of the combustion chamber 1 and detecting flame in the combustion chamber 1 over the water film formed on the inner peripheral face of the combustion chamber 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exhaust gas treatment apparatus for detoxifying an exhaust gas discharged from a manufacturing apparatus for producing a semiconductor device, a liquid crystal, an LED, or the like.

The semiconductor manufacturing apparatus emits gas containing toxic gas such as silane gas (SiH ₄ ) or halogen-based gas (NF ₃ , ClF ₃ , SF ₆ , CHF ₃ , C ₂ F ₆ , CF ₄ ). Such exhaust gas (process gas) cannot be released into the atmosphere as it is. Therefore, it is generally performed that these exhaust gases are guided to a detoxification device and subjected to oxidation detoxification treatment by combustion. As this treatment method, a combustion type exhaust gas treatment device (combustion type abatement device) that forms a flame in a furnace using fuel gas and performs exhaust gas treatment is widely adopted. Since the gas is processed by mixing the processing gas with the flame, a large amount of dust (mainly SiO ₂ ) and a large amount of acid gas are expected as a by-product of the combustion process.

In a combustion type abatement device or a combustor such as a boiler, the presence or absence of a flame is monitored by a UV sensor using a photomultiplier tube, a thermocouple, or a frame rod.
The photomultiplier tube system has a structure in which a photocathode, a secondary electron multiplier electrode called a dynode, an anode, and other electrodes are enclosed in a glass container. When an initial applied voltage is applied to the two electrodes and ultraviolet rays radiated from the flame hit the electrode surface, photoelectrons are emitted by the photoelectric effect, ionizing the enclosed argon gas, and a discharge current flows. This discharge current is output as a flame signal via a frame monitor relay, and the presence / absence of UV is regarded as the presence / absence of a flame and used as a flame detector.

Japanese Patent No. 4497726

Photomultiplier tubes are structurally self-discharged due to changes in the gap between the cathode and anode, replacement of argon gas sealed in a glass container, etc. It is known. As a safety measure, there are problems that a self-discharge phenomenon is always confirmed with a shutter, and measures such as ensuring reliability are required by installing a plurality of UV tubes.
It is also known that photomultiplier tubes have a high initial failure rate due to quality problems. Furthermore, since the photomultiplier tube needs to be replaced regularly in about one year, the maintenance frequency is high when used in a combustion type abatement device for semiconductor manufacturing equipment that operates for 24 hours. There is. In addition, in order to prevent clogging of by-products such as SiO _{2 at the} site that receives the UV light, it is necessary to always purge this site, and this purged gas is also put into the combustion chamber. It causes a decrease in combustion efficiency.

On the other hand, when an insertion type detector such as a thermocouple or frame rod is used in a combustion type abatement device, the environment to be detected is in a high temperature corrosive environment in the combustion chamber. It is a prerequisite for use. In addition, since by-products such as SiO ₂ are in direct contact with each other, the product is deposited on the thermocouple itself, which may inhibit stable flame detection and may further inhibit flame formation due to product growth. In order to avoid this, when a thermocouple is installed near the cooling section, it becomes difficult to accurately measure the high-temperature gas temperature because the cooling water comes into contact with the thermocouple measuring section, which inhibits stable flame detection. There's a problem. Further, when a misfire occurs, in the case of a combustion chamber having a large amount of heat, it takes time to lower the temperature, and thus there is a problem as a stable flame detection method.

As described above, there are various problems in detecting a flame with a UV sensor using a photomultiplier tube or an insertion detector such as a thermocouple.
The present inventors have found that these problems are that the light-receiving unit for detecting the flame and the detection unit such as a thermocouple are in a high-temperature corrosive environment in the combustion chamber or in a production environment for by-products such as SiO _2. As a result of studying the problem of placing the detection unit for detecting the flame outside the combustion chamber, focusing on the fact that it is caused by the above, the present invention has been invented. Hereinafter, the inventive process will be described.

  In the patent application (unpublished) previously filed in Japanese Patent Application No. 2015-050041 (filed on Mar. 12, 2015), the inventors of the present invention connected fuel, combustion-supporting gas, and processing gas to the tangent line of the inner peripheral surface of the combustion chamber. The invention of the adiabatic mixed combustion method was proposed in which a cylindrical mixed flame of three kinds of mixture that blows in the direction at a flow rate higher than the combustion speed of the flame and floats from the combustion chamber wall is formed. According to the present invention, the swirling centrifugal force forms a distribution of the unburned ternary mixed gas having a low temperature on the outside of the cylindrical mixed flame, and a post-combustion gas having a high temperature and a light ternary mixture on the inside. Therefore, since the cylindrical mixed flame is in a self-insulated state covered with an unburned three-type mixed gas having a low temperature, there is no temperature decrease due to heat dissipation, and a gas treatment with high combustion efficiency is performed.

  In the adiabatic co-firing method, a flame with improved self-insulating properties is formed by co-firing three types of fuel, combustion-supporting gas, and processing gas, so a wet wall outside the cylindrical flame, that is, the inner wall of the combustion chamber Water and hot flames do not come in direct contact with water. Since the temperature rise of water is suppressed, a mixed fire heat insulation flame can be formed inside the wet wall without reducing the combustion efficiency.

  The present inventors pay attention to the wet wall water on the inner wall of the combustion chamber proposed in the patent application (Japanese Patent Application No. 2015-050041) for the heat insulation mixed combustion method, and detect the flame from the outside of the combustion chamber through the wet wall water. The idea of the present invention has been conceived and the present invention has been invented.

  That is, the present invention employs a method of detecting a flame from the outside of the combustion chamber through the wet wall water using wet wall water such as an adiabatic mixed combustion method, thereby enabling a UV sensor or a thermoelectric device using a photomultiplier tube. An object of the present invention is to provide an exhaust gas treatment apparatus that can detect a flame stably and inexpensively without using a pair.

In order to achieve the above-mentioned object, the exhaust gas treatment apparatus of the present invention is an exhaust gas treatment apparatus for detoxifying a process gas by burning it, and forms a cylindrical container with one end closed and the other end opened to burn the process gas. A combustion chamber, an upper wall surface of the combustion chamber, a water supply nozzle for forming a water film (wet wall water) on the inner peripheral surface of the combustion chamber, and a combustion chamber installed on the wall surface of the combustion chamber A flame detector for detecting a flame in the combustion chamber is provided over the water film (over the wet wall water) formed on the inner peripheral surface of the chamber.
According to the present invention, the detection unit for detecting the flame is arranged outside the combustion chamber, and is configured to detect the flame through the wet wall water flowing through the inner wall of the combustion chamber. since the detection unit is not under generation environment of by-products such as high-temperature corrosion environment or SiO ₂ in the combustion chamber, without wasting problems detecting portion of the member, also to by-products such as SiO ₂ is detected portion There are no problems such as adhesion and accumulation. Therefore, a flame can be detected stably by an inexpensive method.

  According to a preferred aspect of the present invention, the flame detector includes a viewing window installed on a wall surface of the combustion chamber, and a sensor that is installed adjacent to the viewing window and detects a flame. And

According to a preferred aspect of the present invention, the sensor includes a photodiode.
According to the present invention, since the semiconductor element is used for flame detection, the replacement period is about 10 years or more, which is said to be the life of the Si semiconductor element, so that periodic replacement due to member wear in a short period is unnecessary. . In addition, the failure mode is the disconnection side, which is a safe side where it is judged that there is no flame, so the necessary measures when using a photomultiplier tube, that is, the installation of multiple UV tubes and complicated structures with shutters There is no need to make it.

According to a preferred aspect of the present invention, the sensor is configured to detect a flame by detecting light emission in a near infrared region from a visible region of 500 nm to 1700 nm.
According to the present invention, by detecting light emission from the visible region to the near infrared region, there is no attenuation due to the passage of wet wall water, and stable flame detection is possible. That is, since detection of light emission from the visible region to the near infrared region is detection of light emission of the flame itself, there is no false detection. Therefore, it can be determined that there is no time delay at the time of misfire, which contributes to improvement of the safety of the apparatus.

According to a preferred aspect of the present invention, the combustion chamber includes a fuel nozzle and a combustion gas nozzle for blowing fuel, a combustion-supporting gas, and a processing gas in a tangential direction of the inner peripheral surface of the combustion chamber, respectively. A nozzle for processing gas, and the nozzle for fuel, the nozzle for supporting gas, and the nozzle for processing gas are located on the same plane orthogonal to the axis of the combustion chamber. Here, being located on the same plane means that a part of the opening of the three nozzles on the circumferential surface side of the combustion chamber is located on the same plane.
According to the present invention, fuel (fuel gas), combustion-supporting gas (oxygen-containing gas), and processing gas (exhaust gas) are simultaneously blown in the tangential direction of the inner peripheral surface of the cylindrical combustion chamber, so that the fuel and The processing gas is combusted with a combustion-supporting gas to form a cylindrical mixed flame. That is, in the combustion chamber, a three-mixed cylindrical mixed flame can be formed in the same combustion field, and the processing gas can be burned.

According to a preferred aspect of the present invention, a cylindrical mixed flame is formed in the combustion chamber by blowing the fuel, the combustion-supporting gas, and the processing gas toward the tangential direction of the inner peripheral surface of the combustion chamber. It is characterized by.
According to the present invention, the swirling centrifugal force forms a distribution of a three-mixed gas having a low temperature and a heavy unburned gas on the outside of the cylindrical mixed flame, and a three-mixed gas having a high temperature and a light temperature on the inside. Therefore, since the cylindrical mixed flame is in a self-insulated state covered with an unburned three-type mixed gas having a low temperature, there is no temperature decrease due to heat dissipation, and a gas treatment with high combustion efficiency is performed.

According to a preferred aspect of the present invention, the combustion chamber includes a fuel nozzle and a combustion gas nozzle for blowing fuel, a combustion-supporting gas, and a processing gas in a tangential direction of the inner peripheral surface of the combustion chamber, respectively. A nozzle for processing gas, the nozzle for fuel supporting gas, and the nozzle for processing gas directing the fuel, the supporting gas and the processing gas in the tangential direction of the inner peripheral surface of the combustion chamber, respectively. It blows in and forms the swirl | vortex flow of the 3 types of said fuel, supporting gas, and process gas, It is characterized by the above-mentioned.
According to the present invention, fuel (fuel gas), combustion-supporting gas (oxygen-containing gas), and processing gas (exhaust gas) are blown in the tangential direction of the inner peripheral surface of the cylindrical combustion chamber, thereby supporting the fuel. A swirling flow of a mixture of flammable gas and process gas is formed. As a result, the fuel and the processing gas are combusted by the combustion-supporting gas to form a cylindrical mixed flame. That is, in the combustion chamber, a three-type mixed cylindrical flame can be formed and the processing gas can be burned.

According to a preferred aspect of the present invention, a cylindrical mixed flame is formed in the combustion chamber by a swirling flow of a triple mixture of the fuel, the combustion-supporting gas, and the processing gas.
According to the present invention, the swirling centrifugal force forms a distribution of a three-mixed gas having a low temperature and a heavy unburned gas on the outside of the cylindrical mixed flame, and a three-mixed gas having a high temperature and a light temperature on the inside. Therefore, since the cylindrical mixed flame is in a self-insulated state covered with an unburned three-type mixed gas having a low temperature, there is no temperature decrease due to heat dissipation, and a gas treatment with high combustion efficiency is performed.
According to a preferred aspect of the present invention, the water film on the inner peripheral surface of the combustion chamber is swirled by the swirling force of the cylindrical mixed flame.

The present invention has the following effects.
(1) Since the detection unit for detecting the flame is arranged outside the combustion chamber and configured to detect the flame through the wet wall water flowing through the inner wall of the combustion chamber, the detection unit for detecting the flame since not under generation environment of by-products such as high-temperature corrosion environment or SiO ₂ in the combustion chamber, without wasting problems detecting portion of the member, also adhesion and deposition by-products such as SiO ₂ is in the detection unit There is no problem to do. Therefore, a flame can be detected stably by an inexpensive method.
(2) Since the light emission of the flame covered with wet wall water is detected, there is no red-hot part around the part where the flame is detected. By detecting near infrared rays, there is no attenuation due to the passage of wet wall water, and stable flame detection is possible. That is, since detection of near infrared rays is detection of light emission of the flame itself, there is no false detection. Therefore, it can be determined that there is no time delay at the time of misfire, which contributes to improvement of the safety of the apparatus.
(3) Like a radiation thermometer, the output of a photodiode has a correlation with temperature, and the temperature of a flame covered with wet wall water can be measured in a non-contact manner. It is also possible to monitor the operating state of the device and the stable combustion state.
(4) Since a flame is detected over the wet wall water, an optical path always washed with water is secured. That is, it is not necessary to consider the inhibition by the product, and it is not necessary to introduce extra purge gas or the like into the combustion chamber, which contributes to energy saving.
(5) A photodiode is used for flame detection, and since the photodiode is a semiconductor element, the lifetime is about 10 years or more, so that periodic replacement due to member wear in a short period is unnecessary. In addition, the failure mode is the disconnection side, which is a safe side where it is judged that there is no flame, so the necessary measures when using a photomultiplier tube, that is, the installation of multiple UV tubes and complicated structures with shutters There is no need to make it.

FIG. 1 is a schematic cross-sectional view showing a configuration example of a combustion chamber of an exhaust gas treatment apparatus of the present invention. 2 is a cross-sectional view taken along line II-II in FIG. FIGS. 3A and 3B show that the set of fuel nozzles, combustion-supporting gas nozzles, and process gas nozzles is a single stage (or the upper stage in the case of two stages), and there are few process gas blowing nozzles. FIG. 3A is a partial vertical cross-sectional view of the combustion chamber, and FIG. 3B is a horizontal cross-sectional view of the combustion chamber. 4 (a) and 4 (b), when the process gas blowing nozzle does not fit in a single stage, a set of fuel nozzles, combustion-supporting gas nozzles, and process gas nozzles is installed in two stages up and down. It is a schematic diagram which shows an example of the lower set of the case, Fig.4 (a) is a partial longitudinal cross-sectional view of a combustion chamber, FIG.4 (b) is a horizontal sectional view. FIGS. 5A and 5B are schematic views showing another example of a lower set when two or more stages are installed in the upper and lower directions when the process gas blowing nozzles cannot be fitted into a single stage. a) is a partial longitudinal sectional view of the combustion chamber, and FIG. 5B is a horizontal sectional view. FIG. 6 is a schematic diagram showing an overall configuration of the exhaust gas treatment apparatus including the combustion chamber shown in FIGS. 1 to 3.

Hereinafter, an embodiment of an exhaust gas treatment apparatus according to the present invention will be described with reference to FIGS. 1 to 6. 1 to 6, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1 is a schematic cross-sectional view showing a configuration example of a combustion chamber of an exhaust gas treatment apparatus of the present invention. The combustion chamber 1 is configured as a cylindrical container-like combustion chamber having one end (upper end in the illustrated example) closed and the other end (lower end in the illustrated example) opened. Fuel (fuel gas), combustion-supporting gas (oxygen-containing gas), and processing gas (exhaust gas) are blown into the cylindrical container-like combustion chamber 1 in the vicinity of the closed end. An ignition pilot burner 2 is installed at the closed end of the combustion chamber 1, and fuel and air are supplied to the pilot burner 2. In FIG. 1, the illustration of the cleaning unit below the combustion chamber 1 is omitted.

  2 is a cross-sectional view taken along line II-II in FIG. As shown in FIG. 2, a fuel nozzle 3 </ b> A that blows fuel, a combustion-supporting gas nozzle 3 </ b> B that blows combustion-supporting gas, and a processing gas nozzle 3 </ b> C that blows processing gas are formed on the inner peripheral surface of the combustion chamber 1. It is installed in the tangential direction. In the example shown in FIG. 3, one fuel nozzle 3A and one fuel-supporting gas nozzle 3B are installed, and two process gas nozzles 3C are installed, but each of the nozzles 3A, 3B, 3C is provided. The number can be changed as appropriate according to the size of the combustion chamber, the installation space, etc., and a plurality of sets of fuel nozzles 3A, combustion-supporting gas nozzles 3B, and processing gas nozzles 3C installed on the same plane are installed. It is also possible to do. In this case, the stability of the flame can be improved by changing the balance of the fuel flow rate, the combustion-supporting gas flow rate, and the processing gas flow rate. The fuel nozzle 3A for injecting fuel, the nozzle 3B for supporting gas for injecting supporting gas, and the nozzle 3C for processing gas for injecting processing gas are on the same plane perpendicular to the axis of the cylindrical combustion chamber 1. positioned. Here, being located on the same plane means that a part of the opening of the three nozzles on the circumferential surface side of the combustion chamber is located on the same plane.

  As shown in FIG. 1, in the combustion chamber 1, a wet wall (water film) is formed on the inner wall surface of the combustion chamber 1 at a position slightly below the position where the fuel, combustion-supporting gas, and processing gas are blown. A water supply nozzle 5 for supplying water is installed.

In the combustion chamber 1 configured as shown in FIGS. 1 and 2, the fuel, the combustion-supporting gas, and the processing gas are combusted from the fuel nozzle 3A, the combustion-supporting gas nozzle 3B, and the processing gas nozzle 3C. It blows in the tangential direction of the inner peripheral surface of the chamber 1 at a flow rate equal to or higher than the combustion speed of the flame. Thereby, a three-mixed cylindrical mixed flame floating from the inner wall of the combustion chamber 1 is formed. The cylindrical mixed flame is formed along the axial direction of the combustion chamber 1. By blowing the three gases together in the tangential direction, a swirling centrifugal force forms a low-temperature, heavy, unburned three-way mixed gas on the outside of the cylindrical mixed flame, and a high-temperature, light, three-way mixed gas distribution on the inside. Is done. Therefore, since the cylindrical mixed flame is in a self-insulated state covered with an unburned three-type mixed gas having a low temperature, there is no temperature decrease due to heat dissipation, and a gas treatment with high combustion efficiency is performed. In addition, since the processing gas is usually diluted with N ₂ gas or the like and flows into the exhaust gas processing apparatus, the processing gas containing this N ₂ gas is mixed with the fuel and the combustion-supporting gas, so that the combustion becomes slow and local Since a high temperature part is not formed, the generation of NOx is suppressed.

Further, by co-firing the processing gas containing N ₂ gas with the fuel and the combustion-supporting gas, the diameter of the cylindrical flame is reduced and the inner wall surface temperature of the combustion chamber 1 is reduced. That is, since the heat insulation of the flame, which is a feature of this combustion method, is promoted, even if a wet wall (water film) is formed on the inner wall surface of the combustion chamber 1 as shown in FIG. Since there is no direct contact, the flame and the combustion gas temperature inside the flame will not decrease. The powder such as SiO ₂ produced after the combustion is collected in the outer wet wall water by the centrifugal force of the gas swirl flow and washed to the lower part, so that it does not accumulate on the inner wall surface of the combustion chamber 1 and burns. Since most of the powder is collected in the wet wall water in the chamber, the scrubber performance (powder removal performance) of the exhaust gas treatment device is improved. Corrosive gas is also washed away by wet wall water, and corrosion of the inner wall surface of the combustion chamber 1 can be prevented. Furthermore, since the inner wall surface of the combustion chamber 1 is kept at a low temperature by the wet wall water, the combustion chamber 1 can be configured with an inexpensive material such as stainless steel without thermal damage, and the manufacturing cost can be reduced. .

  As shown in FIG. 1, a flame detector 6 is installed on the wall surface of the combustion chamber 1 at a position below the water supply nozzle 5 to detect the flame in the combustion chamber 1 over the wet wall water (over the water film). Has been. The flame detector 6 includes a housing 7 fixed to the wall surface of the combustion chamber 1, a heat resistant glass 8 such as quartz glass accommodated in the housing 7, and is accommodated in the housing 7 and adjacent to the heat resistant glass 8. It is comprised from the sensor 9 arrange | positioned. The housing 7 has a pipe-like portion 7 a that is fixed to the wall surface of the combustion chamber 1 and guides wet wall water to the front surface of the heat-resistant glass 8, and a housing portion 7 b that houses the heat-resistant glass 8 and the sensor 9. That is, the observation window VW composed of the housing 7 and the heat-resistant glass 8 is installed on the wall surface of the combustion chamber 1 outside the wet wall water, and the sensor 9 is installed close to (adjacent to) the observation window VW. Yes. The sensor 9 is composed of a Si photodiode, and is configured to detect the flame in the combustion chamber 1 through the wet wall water by detecting light emission in the near infrared region from the visible region of 500 nm to 1700 nm. The photodiode is not limited to a Si photodiode, and a photodiode such as germanium, indium, gallium, or arsenic may be used.

The flame detector 6 configured as shown in FIG. 1 has the following effects.
(1) Since the light emission of the flame covered with wet wall water is detected, there is no red-hot part around the part where the flame is detected. By detecting light emission in the near infrared region from the visible region of 500 nm to 1700 nm, there is no attenuation due to the passage of wet wall water, and stable flame detection becomes possible. That is, since detection of near infrared rays is detection of light emission of the flame itself, there is no false detection. Therefore, it can be determined that there is no time delay at the time of misfire, which contributes to improvement of the safety of the apparatus.
(2) Like a radiation thermometer, the output of a photodiode has a correlation with temperature, and the temperature of a flame covered with wet wall water can be measured in a non-contact manner. It is also possible to monitor the operating state of the device and the stable combustion state.
(3) Since the flame is detected through the wet wall water, an optical path always washed with water is secured. That is, it is not necessary to consider the inhibition by the product, and it is not necessary to introduce extra purge gas or the like into the combustion chamber, which contributes to energy saving.
(4) A photodiode is used for flame detection, and since the photodiode is a semiconductor element, the lifetime is about 10 years or more, so that periodic replacement due to member consumption in a short period of time becomes unnecessary. In addition, the failure mode is the disconnection side, which is a safe side where it is judged that there is no flame, so the necessary measures when using a photomultiplier tube, that is, the installation of multiple UV tubes and complicated structures with shutters There is no need to make it.

Next, an example of processing gas (exhaust gas) processing by the combustion chamber 1 configured as shown in FIGS. 1 and 2 will be described.
Depending on the amount of treatment gas flowing into the combustion chamber 1, the gas treatment is carried out with the composition of three types of mixture of treatment gas (including N ₂ gas as one of the main components), fuel gas, and combustion-supporting gas within the combustion range. Appropriate fuel and combustion-supporting gas flow rates that can ensure the necessary gas temperature are set. The relationship between the three types of composition and the combustion range will be described by using propane as the fuel gas. In the combustion-supporting gas is pure oxygen, if there is no N ₂ process gas, propane component% relative air-fuel mixture, under the limit of combustion is 2%, the upper limit boundary is 40%. When the combustion-supporting gas is air (composition ratio of N ₂ and O ₂ is 79:21), the propane component% relative to the mixture is known to have a lower limit of combustion of 2% and an upper limit of 10%. It has been. When N _{2 which} is the main processing gas is added to this, for example, when the composition ratio of N ₂ and O ₂ is 85:15, the propane component% with respect to the air-fuel mixture has a lower limit of combustion of 2% and an upper limit. Is known to be 6%. When the fuel gas (fuel) is another gas such as city gas or natural gas, the combustion range of the air-fuel mixture may be obtained by the same method as when propane is the fuel gas. That is, it can be adjusted based on the relationship between the composition of the fuel gas, the combustion-supporting gas (oxygen and air), and the N ₂ mixture of the processing gas and the combustion range. For example, when two sets of the fuel nozzle 3A, the combustion-supporting gas nozzle 3B, and the processing gas nozzle 3C are installed on the same plane, the balance of the fuel flow rate, the combustion-supporting gas flow rate, and the processing gas flow rate ( The stability of the flame can be improved by changing the composition ratio), for example, decreasing the amount of processing gas inflow on the upper side and increasing the lower side.

In the embodiment shown in FIGS. 1 and 2, the fuel nozzle 3 </ b> A, the combustion-supporting gas nozzle 3 </ b> B, and the processing gas nozzle 3 </ b> C are located on the same plane perpendicular to the axis of the cylindrical combustion chamber 1. Although the case has been described, even if the three nozzles 3A, 3B, and 3C are displaced in the axial direction of the combustion chamber 1, the combustion is performed if the following conditions (1) and (2) are satisfied. A three-mixed cylindrical mixed flame floating from the inner wall of the chamber 1 can be formed. The nozzles 3A, 3B, and 3C may be divided into a plurality of parts and spaced apart in the circumferential direction of the combustion chamber 1.
(1) Fuel nozzle 3A, combustion-supporting gas nozzle 3B, and processing gas nozzle 3C inject fuel (fuel gas), combustion-supporting gas, and processing gas in the tangential direction of the inner peripheral surface of the combustion chamber. Thus, a swirling flow of three kinds of mixture of fuel, supporting gas and processing gas is formed.
(2) When at least one of the fuel (fuel gas), the combustion-supporting gas, and the processing gas blown into the combustion chamber is blown into the combustion chamber lastly to form a swirling flow of three kinds, three kinds The composition of the air-fuel mixture reaches the combustion range.
By satisfying the above conditions (1) and (2), a three-mixed cylindrical mixed flame floating from the inner wall of the combustion chamber 1 can be formed, but after the three-mixed cylindrical mixed flame is formed. , A fuel nozzle 3A and a processing gas nozzle 3C are further provided on the downstream side (rear stage) of the fuel nozzle 3A, the combustion-supporting gas nozzle 3B, and the processing gas nozzle 3C, and fuel and processing are performed from these nozzles. By injecting the gas, the combustion temperature can be improved and the gas processing performance can be improved.

Next, various aspects satisfying the above conditions (1) and (2) will be described with reference to the drawings.
First, as a nozzle that is first blown into the combustion chamber 1 to form a swirl flow, that is, a nozzle that starts swirl flow, which of the fuel nozzle 3A, the combustion-supporting gas nozzle 3B, and the process gas nozzle 3C How to select a nozzle will be described, and how to arrange other nozzles toward the downstream side of the swirling flow based on the selected nozzle will be described.

3 (a) and 3 (b) show that the set of the fuel nozzle 3A, the combustion-supporting gas nozzle 3B, and the processing gas nozzle 3C is a single stage (or the upper stage in the case of two stages), and the processing gas is injected. FIG. 3A is a schematic diagram showing a case where there are few (one) nozzles, FIG. 3A is a partial longitudinal sectional view of the combustion chamber, and FIG. 3B is a horizontal sectional view of the combustion chamber.
When the combustion-supporting gas is air and the air ratio is 1.3, air that is about 15 times the fuel flow rate is required. In this case, the air flow rate and flow velocity dominate the turning force in the combustion chamber. Therefore, as shown in FIGS. 3A and 3B, the combustion-supporting gas nozzle 3 </ b> B that blows in air as the combustion-supporting gas is selected as a nozzle that starts swirling flow. By selecting the combustion-supporting gas nozzle 3B as the nozzle for starting the swirling flow, the top plate of the combustion chamber is cooled by the combustion-supporting gas immediately before the flame is formed. This contributes to energy saving.

Then, the processing gas nozzle 3 </ b> C and the fuel nozzle 3 </ b> A are arranged in this order toward the downstream side of the swirl flow with the selected combustion-supporting gas nozzle 3 </ b> B as a reference. That is, by providing the processing gas nozzle 3C for blowing the processing gas mainly composed of the diluted N ₂ between the combustion supporting gas nozzle 3B and the fuel nozzle 3A, the supporting gas is processed gas (N ₂ Since the fuel gas is mixed and ignited after mixing with the main body), a flame having a uniform temperature field is formed without forming a local high temperature portion. Thereby, generation | occurrence | production of thermal NOx can be suppressed, improving gas processing performance.
3A and 3B, the fuel nozzle 3 </ b> A, the combustion-supporting gas nozzle 3 </ b> B, and the processing gas nozzle 3 </ b> C are located on the same plane perpendicular to the axis of the cylindrical combustion chamber 1. Although the configuration has been illustrated, when the three nozzles 3A, 3B, 3C are shifted in the axial direction of the combustion chamber 1, the combustion-supporting gas nozzle 3B is arranged in the uppermost stage in FIG. The processing gas nozzle 3C and the fuel nozzle 3A may be shifted in the order downward. In the cross-sectional view shown in FIG. 3A, the nozzle 3C located on the near side (front side) of the cross section is indicated by a virtual line. The same applies to the following drawings.

4 (a) and 4 (b) show that the set of the fuel nozzle 3A, the combustion-supporting gas nozzle 3B, and the processing gas nozzle 3C is vertically moved up and down when the processing gas blowing nozzles cannot enter a single stage. It is a schematic diagram which shows an example of the set of the lower stage at the time of installing in stages, Fig.4 (a) is a partial longitudinal cross-sectional view of a combustion chamber, FIG.4 (b) is a horizontal sectional view.
As shown in FIGS. 4A and 4B, in the lower set, the combustion-supporting gas nozzle 3B is disposed on the most upstream side of the swirling flow, and the swirling flow nozzle 3B is used as a reference. A processing gas nozzle 3C-1, a processing gas nozzle 3C-2, a fuel nozzle 3A, and a processing gas nozzle 3C-3 are arranged in this order toward the downstream side.
Thus, since the gas mixing degree is made uniform by providing three types of nozzles 3A, 3B, 3C-1, 3C-2, and 3C-3 in the lower set as well, a local high temperature portion is formed. Without any problem, a flame having a uniform temperature field can be formed. Thereby, generation | occurrence | production of thermal NOx can be suppressed, improving gas processing performance.

FIGS. 5A and 5B are schematic views showing another example of a lower set when two or more stages are installed in the upper and lower directions when the process gas blowing nozzles cannot be fitted into a single stage. a) is a partial longitudinal sectional view of the combustion chamber, and FIG. 5B is a horizontal sectional view.
As shown in FIGS. 5A and 5B, in the lower set, the processing gas nozzle 3C-1 is arranged on the uppermost stream side of the swirling flow, and the swirling flow is set with reference to the processing gas nozzle 3C-1. The processing gas nozzle 3C-2, the fuel nozzle 3A, and the processing gas nozzle 3C-3 are arranged in this order toward the downstream side.
When a hardly decomposable gas or the like flows into the combustion chamber as a processing gas, it is necessary to add oxygen to the air of the combustion supporting gas to form a high temperature field. When it is necessary to form a high temperature field, the upper set has the same configuration as the set of FIGS. 3A and 3B, and the lower set is shown in FIGS. 4A and 4B. As the set shown in FIGS. 5A and 5B excluding the nozzle for supporting gas from the set, the nozzle for supporting gas is provided only in the upper set. The formation position of the flame moves to the swirl upstream side as compared with the case of the lower set shown in FIGS. 4A and 4B, and the flame volume can be reduced, so that a higher temperature field can be formed. .

  In the combustion chamber 1 configured as shown in FIGS. 1 to 3, the fuel gas, the combustion-supporting gas, and the processing gas are blown at a flow rate that is equal to or higher than the combustion speed of the flame. In this case, the flow rates of the fuel gas, the combustion-supporting gas, and the processing gas are adjusted so that the swirl number (a dimensionless number representing the degree of turning) is 5-40. Thus, a desired cylindrical mixed flame can be formed by adjusting the flow rates of the fuel gas, the combustion-supporting gas, and the processing gas based on the swirl number.

FIG. 6 is a schematic diagram showing an overall configuration of the exhaust gas treatment apparatus including the combustion chamber 1 shown in FIGS. 1 to 3. As shown in FIG. 6, the exhaust gas treatment apparatus includes a combustion chamber 1 (see FIG. 1) that combusts a process gas (exhaust gas) and oxidatively decomposes, and an exhaust gas cleaning unit 30 that is disposed downstream of the combustion chamber 1. I have. The combustion chamber 1 extends downward by a connecting pipe 19. The processing gas (exhaust gas) is supplied through the bypass valve (three-way valve) 23 in the tangential direction of the inner peripheral surface of the cylindrical combustion chamber 1. When there is a problem with the exhaust gas treatment device, the bypass valve 23 is operated, and the processing gas is not introduced into the exhaust gas treatment device, but is sent to a bypass pipe (not shown). Similarly, the fuel and the combustion-supporting gas are supplied in the tangential direction of the inner peripheral surface of the cylindrical combustion chamber 1. As described above, the fuel, the combustion-supporting gas, and the processing gas are directed toward the tangential direction of the inner peripheral surface of the combustion chamber 1 at a flow rate equal to or higher than the combustion speed of the flame. A mixed cylindrical mixed flame is formed. Water W is supplied from the water supply nozzle 5 to the upper part of the combustion chamber 1, and this water W flows down along the inner surface of the combustion chamber 1, and forms a wet wall (water film) on the inner surface of the combustion chamber. The wet wall water collects powder such as SiO ₂ generated by the combustion of the processing gas. On the wall surface of the combustion chamber 1, a flame detector 6 that detects the flame in the combustion chamber 1 over the wet wall water (over the water film) is installed at a position below the water supply nozzle 5.

  A circulating water tank 20 is disposed below the combustion chamber 1. A dam 21 is provided inside the circulating water tank 20, and is divided into an upstream first tank 20A and a downstream second tank 20B. The powder product collected in the wet wall water falls into the first tank 20A of the circulating water tank 20 through the connection pipe 13, and accumulates at the bottom of the first tank 20A. Further, the wet wall water flowing down the inner surface of the combustion chamber 1 flows into the first tank 20A. The water in the first tank 20A overflows the weir 21 and flows into the second tank 20B.

  The combustion chamber 1 communicates with the exhaust gas cleaning unit 30 via the cooling unit 25. The cooling unit 25 includes a pipe 26 extending toward the connection pipe 13 and a spray nozzle 27 disposed in the pipe 26. The spray nozzle 27 injects water so as to face the exhaust gas flowing through the pipe 26. Therefore, the exhaust gas treated by the combustion chamber 1 is cooled by the water ejected from the spray nozzle 27. The injected water is collected in the circulating water tank 20 through the pipe 26.

  The cooled exhaust gas is then introduced into the exhaust gas cleaning unit 30. The exhaust gas cleaning unit 30 is an apparatus that cleans the exhaust gas with water and removes fine dust contained in the exhaust gas. This dust is mainly a powder product generated by oxidative decomposition (combustion treatment) in the combustion chamber 1.

  The exhaust gas cleaning unit 30 includes a wall member 31 that forms a gas flow path 32, a first mist nozzle 33A, a first water film nozzle 33B, a second mist nozzle 34A, and the like disposed in the gas flow path 32. A second water film nozzle 34B. The mist nozzles 33A and 34A and the water film nozzles 33B and 34B are located in the center of the gas flow path 32 and are arranged in a substantially linear shape. The first mist nozzle 33A and the first water film nozzle 33B constitute a first nozzle unit 33, and the second mist nozzle 34A and the second water film nozzle 34B constitute a second nozzle unit 34. Therefore, in this embodiment, two sets of nozzle units 33 and 34 are provided. One nozzle unit may be provided, or three or more nozzle units may be provided.

  The first mist nozzle 33A is disposed upstream of the first water film nozzle 33B in the exhaust gas flow direction. Similarly, the second mist nozzle 34A is arranged on the upstream side of the second water film nozzle 34B. That is, mist nozzles and water film nozzles are alternately arranged. The mist nozzles 33A and 34A, the water film nozzles 33B and 34B, and the wall member 31 are made of a corrosion-resistant resin (for example, PVC: polyvinyl chloride).

  On the upstream side of the first mist nozzle 33A, a rectifying member 40 that rectifies the flow of exhaust gas is disposed. The rectifying member 40 causes a pressure loss of the exhaust gas to make the flow of the exhaust gas in the gas flow path 32 uniform. The rectifying member 40 is preferably made of a material other than metal in order to prevent acid corrosion. Examples of the rectifying member 40 include a non-woven material made of resin and a resin plate in which a plurality of openings are formed. A mist nozzle 41 is disposed on the upstream side of the rectifying member 40. The mist nozzles 33A, 34A, 41 and the water film nozzles 33B, 34B are attached to the wall member 31.

  As shown in FIG. 6, the exhaust gas is introduced into the exhaust gas cleaning unit 30 from a pipe 26 provided in the lower part of the exhaust gas cleaning unit 30. The exhaust gas flows from the bottom to the top in the exhaust gas cleaning unit 30. More specifically, the exhaust gas introduced from the pipe 26 first goes to the mist nozzle 41 of the exhaust gas cleaning unit 30. The exhaust gas passes through the mist formed by the mist nozzle 41 and is rectified by the rectifying member 40. The exhaust gas that has passed through the rectifying member 40 forms a uniform flow and moves up the gas flow path 32 at a low speed. In the gas flow path 32, a mist, a water film, a mist, and a water film are formed in this order.

  The fine dust having a diameter of less than 1 μm contained in the exhaust gas easily adheres to the water droplets constituting the mist by the diffusion action (Brownian motion), and is thereby captured by the mist. Most of the dust having a diameter of 1 μm or more is also trapped in the water droplets. Since the diameter of the water droplet is about 100 μm, the size (diameter) of the dust adhered to the water droplet is apparently increased. Therefore, the water droplets containing dust easily collide with the downstream water film due to inertial collision, and the dust is removed from the exhaust gas together with the water particles. Dust having a relatively large diameter that has not been captured by mist is also captured and removed by the water film in the same manner. The exhaust gas thus washed with water is discharged from the upper end of the wall member 31.

  As shown in FIG. 6, the circulating water tank 20 described above is located below the exhaust gas cleaning unit 30. The water supplied from the mist nozzles 33A, 34A, 41 and the water film nozzles 33B, 34B is collected in the second tank 20B of the circulating water tank 20. The water stored in the second tank 20B is supplied to the mist nozzles 33A, 34A, 41 and the water film nozzles 33B, 34B by the circulating water pump P. At the same time, the circulating water is sent to the upper portion of the combustion chamber 1 as water W, and forms a wet wall on the inner surface of the combustion chamber 1 as described above.

  The water supplied to the mist nozzles 33A, 34A and the water film nozzles 33B, 34B is water collected in the circulating water tank 20, and contains dust (powder product etc.). Accordingly, city water is supplied from the shower nozzle 50 to the gas flow path 32 in order to clean the gas flow path 32. A mist trap 51 is provided above the shower nozzle 50. The mist trap 51 has a plurality of baffle plates therein and can capture the mist. In this way, the treated and detoxified exhaust gas is finally released to the atmosphere through the exhaust duct.

  The circulating water tank 20 is provided with a water level sensor 55. The water level sensor 55 monitors the water level of the second tank 20B and can control the water level of the second tank 20B within a predetermined range. A part of the water transferred by the circulating water pump P is supplied to a plurality of eductors 53 installed in the circulating water tank 20 through the water supply pipe 52. The water supply pipe 52 is provided with an on-off valve V1, and the eductor 53 can be supplied with water by opening the on-off valve V1. The circulating water tank 20 is provided with a drain valve V2 for draining the circulating water tank 20.

  The water in the circulating water tank 20 is pressurized and supplied to each eductor 53 by the circulating water pump P, and the pressure drop generated when the water flow is throttled by the nozzles of each eductor 53 from the suction port of the eductor 53. The water in the circulating water tank 20 is sucked into the eductor 53, and the sucked water is jetted from the discharge port of the eductor 53 to the bottom of the circulating water tank 20 together with the water discharged from the nozzle of the eductor 53. The powder at the bottom of the circulating water tank 20 is crushed and floated by the jetting force of the jet water jetted from the discharge port of the eductor 53, and the powder together with the waste water is discharged from the drain port 20D of the circulating water tank 20. Discharge automatically.

  Although the embodiment of the present invention has been described so far, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention may be implemented in various different forms within the scope of the technical idea.

DESCRIPTION OF SYMBOLS 1 Combustion chamber 1a Opening 2 Pilot burner 3A Fuel nozzle 3B Combustion gas nozzle 3C, 3C-1, 3C-2, 3C-3 Process gas nozzle 5 Water supply nozzle 6 Flame detector 7 Housing 7a Pipe-shaped part 7b Housing 8 Heat-resistant glass 9 Sensor 19 Connection pipe 20 Circulating water tank 20A, 20B Tank 20D Drain port 21 Weir 23 Bypass valve (three-way valve)
25 cooling section 26 piping 27 spray nozzle 30 exhaust gas cleaning section 31 wall member 32 gas flow path 33A first mist nozzle 33B first water film nozzle 34A second mist nozzle 34B second water film nozzle 40 rectifying member 41 mist Nozzle 50 Shower nozzle 51 Mist trap 52 Water supply pipe 53 Eductor 55 Water level sensor AR Air chamber MR Mixture chamber P Circulating water pump PF Pilot flame V1 Open / close valve V2 Drain valve VW Peep window

Claims (9)

In exhaust gas treatment equipment that detoxifies the treatment gas by burning it,
A cylindrical chamber with one end closed and the other end open, and a combustion chamber for burning process gas;
A water supply nozzle installed on the upper wall surface of the combustion chamber, for forming a water film on the inner peripheral surface of the combustion chamber;
An exhaust gas treatment apparatus comprising: a flame detector that is installed on a wall surface of the combustion chamber and detects a flame in the combustion chamber through a water film formed on an inner peripheral surface of the combustion chamber.   2. The exhaust gas according to claim 1, wherein the flame detector includes an observation window installed on a wall surface of the combustion chamber, and a sensor that is installed adjacent to the observation window and detects a flame. Processing equipment.   The exhaust gas treatment apparatus according to claim 2, wherein the sensor is a photodiode.   The exhaust gas treatment apparatus according to claim 2 or 3, wherein the sensor is configured to detect a flame by detecting light emission in a near infrared region from a visible region of 500 nm to 1700 nm. The combustion chamber includes a fuel nozzle, a fuel-supporting gas nozzle, and a processing gas nozzle that blow fuel, a combustion-supporting gas, and a processing gas toward the tangential direction of the inner peripheral surface of the combustion chamber, respectively.
5. The fuel nozzle, the combustion-supporting gas nozzle, and the processing gas nozzle are located on the same plane orthogonal to the axis of the combustion chamber. The exhaust gas treatment apparatus described.   6. A cylindrical mixed flame is formed in the combustion chamber by blowing the fuel, a combustion-supporting gas, and a processing gas toward a tangential direction of an inner peripheral surface of the combustion chamber. Exhaust gas treatment equipment. The combustion chamber includes a fuel nozzle, a fuel-supporting gas nozzle, and a processing gas nozzle that blow fuel, a combustion-supporting gas, and a processing gas toward the tangential direction of the inner peripheral surface of the combustion chamber, respectively.
The nozzle for fuel, the nozzle for combustion-supporting gas, and the nozzle for processing gas blow the fuel, the combustion-supporting gas, and the processing gas toward the tangential direction of the inner peripheral surface of the combustion chamber, respectively. The exhaust gas treatment apparatus according to any one of claims 1 to 4, wherein a swirling flow of three kinds of a mixed gas and a processing gas is formed.   8. The exhaust gas treatment apparatus according to claim 7, wherein a cylindrical mixed flame is formed in the combustion chamber by a swirling flow of a triple mixture of the fuel, a combustion-supporting gas, and a processing gas.   The exhaust gas treatment apparatus according to claim 6 or 8, wherein a water film on an inner peripheral surface of the combustion chamber is swirled by a swirling force of the cylindrical mixed flame.

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