JP2013040749A - Combustion detoxifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion detoxifying device that is able to efficiently perform detoxifying processing of the harmful gas component in a gas to be processed such as exhaust gas containing a combustible gas component as the harmful gas component.SOLUTION: The combustion detoxifying device 10 is provided with: a gas-to-be-processed introduction nozzle 12 that introduces the gas to be processed containing a harmful gas component; an oxidizer introduction nozzle 13 that introduces an oxidizer from the outer periphery of the gas-to-be-processed introduction nozzle; an ignition burner 14 that forms a pilot flame within a combustion chamber 11; and a hydrogen introduction unit 16 that introduces hydrogen that is to be the combustion fuel into the gas to be processed supplied to the gas-to-be-processed introduction nozzle. The nozzle axial line 13a of the oxidizer introduction nozzle is disposed in a direction facing towards the line of extension of the nozzle axial line 12a of the gas-to-be-processed introduction nozzle.

Description

  The present invention relates to a combustion abatement apparatus, and more particularly, to a combustion abatement apparatus that performs a detoxification process for harmful gas components contained in exhaust gas discharged from a manufacturing process such as a compound semiconductor or a solar cell.

  Exhaust gas emitted from manufacturing processes such as compound semiconductors and solar cells contains various harmful gas components used in the manufacturing process, such as combustible gas components and toxic gas components. It is necessary to remove these harmful gas components before discharging. 2. Description of the Related Art Combustion abatement devices are widely used as devices for removing harmful gas components. In this combustion abatement apparatus, the exhaust gas is introduced into a high-temperature combustion gas obtained by burning hydrocarbon-based fuel with an oxygen-containing gas (oxidant) such as air, and harmful gas components in the exhaust gas are burned. By performing thermal decomposition, harmful gas components are removed from the exhaust gas, and the exhaust gas is removed.

  On the other hand, in recent manufacturing processes for compound semiconductors, solar cells, and the like, a large amount of hydrogen has been used, and thus a large amount of hydrogen may be contained in the exhaust gas from the manufacturing process. When processing exhaust gas containing a large amount of hydrogen in this way, in a general combustion abatement apparatus, the removal efficiency of harmful gas components decreases due to the relationship between the combustion speed of fuel and the combustion speed of hydrogen, etc. There was a thing. On the other hand, as a combustion abatement apparatus for detoxifying exhaust gas containing ammonia as a combustible gas component, a hydrogen introduction nozzle is arranged in a ring shape around the exhaust gas introduction nozzle for introducing exhaust gas into the combustion chamber, and the hydrogen A combustion gas introduction nozzle that introduces a combustion gas that is a mixture of hydrocarbon fuel and oxidant in a ring shape is placed on the outer periphery of the introduction nozzle, and hydrogen is added to the combustion flame, and ammonia is heated by the heat of hydrogen combustion. A device that decomposes and burns has been proposed (see, for example, Patent Document 1).

JP 2008-540990 A

  However, in the apparatus described in Patent Document 1, mixing of the exhaust gas introduced into the chamber from the exhaust gas introduction nozzle and hydrogen is insufficient, and furthermore, oxygen in the combustion gas and hydrogen having a high combustion rate are generated. Because it reacts abruptly, the ammonia in the exhaust gas cannot be heated sufficiently by the combustion heat of hydrogen in a chamber of a general size, and the combustion speed is extremely slow compared to hydrogen. The function was not able to be fully demonstrated.

  Accordingly, an object of the present invention is to provide a combustion abatement apparatus that can efficiently detoxify a harmful gas component in a gas to be treated such as exhaust gas containing a combustible gas component as a harmful gas component.

  In order to achieve the above object, a combustion abatement apparatus of the present invention is a combustion abatement apparatus that detoxifies a harmful gas component contained in a gas to be treated by a combustion flame. A gas to be treated introduction nozzle to be introduced into the chamber, an oxidant introduction nozzle for introducing an oxidant into the combustion chamber from the outer peripheral side of the combustion gas introduction nozzle to the gas to be treated, and an inside of the combustion chamber from the gas to be treated introduction nozzle. An ignition burner that ignites a mixed gas in which the gas to be treated introduced and the oxidant introduced from the oxidant introduction nozzle into the combustion chamber are mixed; and the gas to be treated is introduced to the gas to be treated nozzle. A hydrogen introduction section for introducing hydrogen as a fuel for combustion and mixing the hydrogen and the gas to be processed in the gas supply path to be supplied; The nozzle axis of the introduction nozzle, is characterized in that arranged above the direction toward an extension of the nozzle axis of the processing gas introducing nozzle.

  The combustion abatement apparatus of the present invention is particularly effective for the combustion abatement treatment of a gas to be treated containing ammonia as a harmful gas component, and the combustion chamber has an outer cylinder and an inner periphery of the outer cylinder. The inner gas cylinder is formed of an inner cylinder made of a gas permeable material, and the process gas introduction nozzle and the oxidant introduction nozzle introduce a process gas and an oxidant into a combustion chamber formed in the inner cylinder. Preferably, an air chamber is provided between the inner cylinder and the outer cylinder, and an air chamber through which the air introduced through the inner cylinder and introduced into the combustion chamber is supplied from the outside of the outer cylinder, The ignition burner is preferably a burner in which hydrogen is activated by a catalyst and burned.

  Furthermore, the combustion abatement apparatus of the present invention can be used in the process when the gas to be treated is exhaust gas discharged from a process that uses hydrogen in a part of the process, and when the amount of hydrogen used in the process is small. At least a part of the hydrogen to be used can be introduced from the hydrogen introduction part as hydrogen for combustion fuel.

  According to the combustion abatement apparatus of the present invention, hydrogen is introduced into the gas to be treated containing a harmful gas component and then introduced into the chamber, mixed with an oxidant and burned. Can be sufficiently brought into contact with each other, and the decomposition of harmful gas components by the combustion heat of hydrogen can be efficiently performed. Furthermore, by generating hydrogen by burning hydrogen without using hydrocarbon fuel, the amount of carbon dioxide generated can be greatly reduced. In particular, when the harmful gas component is ammonia which is a combustible gas component having a slow combustion rate, decomposition and combustion of ammonia can be effectively promoted.

  Furthermore, by introducing the air into the combustion chamber of the chamber by allowing the chamber to have a double structure and permeating the inner cylinder made of a gas permeable material from the outer air chamber, a sufficient amount of oxygen can be introduced into the combustion chamber. A stable combustion state, and by constantly supplying air from the outside into the air chamber, the temperature rise of the inner cylinder and the outer cylinder can be suppressed. Also, by using hydrogen as the fuel for the ignition burner, no fuel other than hydrogen is required, and the utility efficiency can be improved.

  In particular, when detoxifying exhaust gas discharged from a process that uses hydrogen, when the amount of hydrogen used in the process is small, hydrogen prepared for the process is removed from the hydrogen introduction part of the combustion abatement apparatus. By introducing, the harmful gas component contained in the exhaust gas can be removed with hydrogen from the process hydrogen supply facility. Thereby, it is not necessary to provide a hydrogen supply facility for the combustion abatement apparatus, and the facility cost for the abatement treatment can be reduced. In addition, when hydrogen is used in the process, since the exhaust gas from the process contains hydrogen, a sufficient combustion state can be obtained even if the amount of hydrogen introduced from the hydrogen introduction part is reduced or stopped. Therefore, it is possible to continue the detoxification process of the harmful gas component, and to reduce the amount of hydrogen used as the combustion fuel introduced from the hydrogen introduction part.

It is explanatory drawing which shows the example of 1 form of the combustion abatement apparatus of this invention. It is explanatory drawing which shows an example of the semiconductor manufacturing equipment which incorporated the combustion elimination apparatus of this invention in the semiconductor manufacturing apparatus. It is a figure which shows the change state of the gas introduction amount in a combustion abatement apparatus and a semiconductor manufacturing apparatus.

  A combustion abatement apparatus 10 shown in the present embodiment includes a gas to be processed introduction nozzle for introducing a gas to be processed into the combustion chamber 11 into a top plate portion of a cylindrical combustion chamber 11 whose axis is directed in the vertical direction. 12 and an oxidant introduction nozzle 13 arranged concentrically on the outer periphery of the gas to be treated introduction nozzle 12 and an ignition burner 14 penetrating the peripheral wall of the combustion chamber 11. Further, hydrogen to be treated as fuel for combustion is introduced into the treated gas supply path 15 for supplying the treated gas to the treated gas introduction nozzle 12, and the hydrogen and the treated gas are introduced into the treated gas supply path 15. A hydrogen introduction part 16 for mixing gas is provided.

  The combustion chamber 11 has a double cylinder structure including a sealed metal outer cylinder 17 and an inner cylinder 18 made of a gas permeable material disposed on the inner periphery of the outer cylinder 17. A combustion chamber 19 is formed on the inner peripheral side of the cylinder, and an air chamber 20 is formed between the outer cylinder 17 and the inner cylinder 18. The peripheral wall of the outer cylinder 17 is provided with an air supply port 22 having a damper 21 for adjusting the amount of air supplied from outside the apparatus into the air chamber 20. By supplying air from the outside, the air is introduced into the combustion chamber 19 through the inner cylinder 18 formed of a gas permeable material such as a perforated plate or a metal mesh.

  Further, a cooling cylinder 23 having an axis line in the horizontal direction is connected to the combustion gas exhaust port opened at the lower end of the combustion chamber 11. One end of the cooling cylinder 23 is provided with a cooling air inlet 24 for cooling the combustion exhaust gas via a damper 25. The other end opening of the cooling cylinder 23 is provided with cooling means or solid as required. An exhaust pipe (not shown) is connected via the separation means.

  The process gas introduction nozzle 12 is arranged with the nozzle axis 12a directed in the chamber axis direction, and is formed so as to introduce the process gas in a downward flow along the chamber axis. On the other hand, the oxidant introduction nozzle 13 has a large number of nozzle openings arranged on one concentric circle on the outer periphery of the gas introduction nozzle 12, and the nozzle axis 13 a of each nozzle opening in the oxidant introduction nozzle 13. Is arranged so that an oxidant is introduced in a direction toward the focal point with a point on the extended line of the nozzle axis of the gas to be treated nozzle 12 as a focal point.

  Therefore, the gas to be processed for performing the combustion detoxification process is processed in a state in which it is sufficiently mixed with the hydrogen introduced from the hydrogen introduction part 16 in the gas supply path 15 to be processed located at the base of the gas introducing nozzle 12 to be processed. The gas is introduced into the combustion chamber 11 from the gas introduction nozzle 12 and flows downward in the combustion chamber 11 while being encased in the oxidant introduced into the combustion chamber 11 from the oxidant introduction nozzle 13.

  The ignition burner 14 forms a fire at a portion where the gas to be treated in the hydrogen mixed state is mixed with the oxidant, and reacts hydrogen in the gas to be treated with oxygen in the oxidant by the fire. To form a combustion flame. The ignition burner 14 can be an ordinary ignition burner using fossil fuel, but by using a hydrogen ignition burner using a highly active catalyst for hydrogen, a part of the hydrogen of the combustion fuel can be used. Since it can be used for the formation of seed fire, the facility for supplying the fuel for forming the seed fire can be omitted.

  When hydrogen of the fuel for combustion reacts with the oxidant and burns by the ignition of the ignition burner 14, the hydrogen introduced from the hydrogen introduction part 16 is mixed with the gas to be treated. The toxic gas components contained in it can be heated effectively with the combustion heat of hydrogen, and even toxic gas components with a slow combustion rate can be heated sufficiently, and various toxic gas components are pyrolyzed. Or by causing it to react with an oxidizing agent and burning it, so that the detoxification treatment can be carried out reliably.

  Further, by introducing air supplied from outside the apparatus into the air chamber 20 through the inner cylinder 18 and introducing it into the combustion chamber 19, more oxygen than that required for combustion in the combustion chamber 19 is combusted. Since the entire chamber 19 can be supplied uniformly, a more reliable combustion state in the combustion chamber 19 can be obtained. Moreover, the temperature rise of the outer cylinder 17 or the inner cylinder 18 can be suppressed by always supplying air from the outside into the air chamber 20.

  FIG. 2 shows an example of a semiconductor manufacturing facility in which the combustion abatement apparatus 10 is incorporated in a semiconductor manufacturing apparatus (MOCVD) 30 that uses hydrogen and ammonia as process gases. In the following description, the same components as those of the combustion abatement apparatus shown in the above-described embodiment are designated by the same reference numerals, and detailed description thereof is omitted. The ignition burner 14 is a hydrogen ignition burner using a highly active catalyst for hydrogen.

  The semiconductor manufacturing apparatus 30 manufactures a compound semiconductor such as an LED and a solar cell by vapor-phase-growing a compound semiconductor thin film on a substrate surface using an organometallic compound and ammonia as a source gas, hydrogen and nitrogen as a carrier gas, In addition to the ammonia supply path 31 from the ammonia supply source and the hydrogen supply path 32 from the hydrogen supply source, an organic metal compound supply path and a nitrogen supply path (not shown) are provided on the gas inlet side of the semiconductor manufacturing apparatus 30. . Further, an exhaust gas path 34 provided with a dry shield type vacuum pump 33 using nitrogen as a seal gas is provided on the gas outlet side of the semiconductor manufacturing apparatus 30.

  The ammonia supply path 31 and the hydrogen supply path 32 are provided with gas supply valves 31V and 32V and flow meters 31F and 32F, respectively. By opening and closing the gas supply valves 31V and 32V according to commands from the control device 35, respectively. The supply state of ammonia and hydrogen to the semiconductor manufacturing apparatus 30 is controlled.

  Further, from the hydrogen supply source side of the hydrogen supply path 32, hydrogen for seed formation is supplied to the hydrogen supply path 36 for the abatement apparatus connected to the hydrogen introduction unit 16 of the combustion abatement apparatus 10 and the ignition burner 14. A hydrogen supply path 37 for the ignition burner branches off. The hydrogen supply path 36 for the abatement apparatus is provided with a gas supply valve 36V and a flow meter 36F that are controlled to be opened and closed by a command from the control device 35. Combustion removal according to the operating state of the semiconductor manufacturing apparatus 30 is provided. The amount of hydrogen introduced into the harm apparatus 10 is adjusted.

  As shown in FIG. 3A, in the semiconductor manufacturing apparatus 30, the amount of supplied gas changes during one step of vapor phase growth of the compound semiconductor thin film, and the vapor phase passes through a preliminary stage such as preheating from the start of the process (t0). Until the start of growth (t1), the supply amount of hydrogen (H2) is large with respect to ammonia (NH3). When vapor phase growth onto the substrate starts in the middle of the process, the supply amount of hydrogen (H2) decreases and ammonia is added. The supply amount of (NH3) increases. Further, when the vapor phase growth is completed near the end of the process (t2) and the vapor phase growth is completed on the substrate, a large amount of hydrogen (H2) is supplied and the supply amount of ammonia (NH3) is substantially halved. It will be in the state. Nitrogen (N2) is continuously supplied in a constant amount from the process start (t0) to the process end (t3).

  When the exhaust gas from the semiconductor manufacturing apparatus 30 in which the hydrogen supply amount is changed in this way is detoxified, the ignition burner hydrogen supply path 37 in the combustion detoxification apparatus 10 is necessary to form a seed fire. An amount of hydrogen is continuously supplied, and the amount of hydrogen supplied to the hydrogen supply path 36 for the abatement apparatus is changed according to the amount of hydrogen in the exhaust gas.

  That is, as shown in FIG. 3B, since the exhaust gas from the start of the process (t0) to the start of vapor phase growth (t1) contains hydrogen in the exhaust gas, the hydrogen supply path for the ignition burner It is only necessary to supply a small amount (L1) of hydrogen to 37, and the amount of hydrogen in the exhaust gas decreases from the beginning of vapor phase growth (t1) to the end of vapor phase growth (t2). In addition to the flow rate (L1), a relatively large amount (L2) of hydrogen capable of obtaining a sufficient combustion state is supplied from the hydrogen supply path 36 for the abatement apparatus to the hydrogen introduction unit 16, and the vapor phase growth is completed (t2). Until the end of the process (t3), the amount of hydrogen in the exhaust gas increases, so that a sufficient combustion state can be obtained without introducing hydrogen from the hydrogen introduction part 16, and a small amount (L1) for the ignition burner can be obtained. It is only necessary to supply hydrogen).

  In this way, the combustion abatement apparatus 10 is incorporated in the semiconductor manufacturing apparatus 30 and formed so as to supply hydrogen for combustion to the combustion abatement apparatus 10 according to the operating state of the semiconductor manufacturing apparatus 30. Without installing a hydrogen supply facility for the apparatus, it is possible to reliably perform detoxification treatment of ammonia having a low combustion rate. Further, when hydrogen is used in the process, since the exhaust gas contains hydrogen, it is possible to continuously form a combustion flame without supplying hydrogen for combustion from the hydrogen introduction part 16. Yes, the utilization efficiency of hydrogen can be increased.

  DESCRIPTION OF SYMBOLS 10 ... Combustion removal apparatus, 11 ... Combustion chamber, 12 ... Process gas introduction nozzle, 12a ... Nozzle axis, 13 ... Oxidant introduction nozzle, 13a ... Nozzle axis, 14 ... Ignition burner, 15 ... Process gas supply path, DESCRIPTION OF SYMBOLS 16 ... Hydrogen introduction part, 17 ... Outer cylinder, 18 ... Inner cylinder, 19 ... Combustion chamber, 20 ... Air chamber, 21 ... Damper, 22 ... Air supply port, 23 ... Cooling cylinder, 24 ... Inlet port, 25 ... Damper, DESCRIPTION OF SYMBOLS 30 ... Semiconductor manufacturing apparatus, 31 ... Ammonia supply path, 31V ... Gas supply valve, 32 ... Hydrogen supply path, 32V ... Gas supply valve, 33 ... Dry shield type vacuum pump, 34 ... Exhaust gas path, 35 ... Control apparatus, 36 ... Hydrogen supply path for detoxifying device, 36V ... gas supply valve, 37 ... hydrogen supply path for ignition burner

Claims (5)

  In a combustion abatement apparatus for detoxifying a harmful gas component contained in a to-be-treated gas by a combustion flame, a to-be-treated gas introduction nozzle for introducing the to-be-treated gas containing the noxious gas component into the combustion chamber, and the to-be-treated gas An oxidant introduction nozzle for introducing an oxidant into the combustion chamber from the outer peripheral side of the combustion chamber of the introduction nozzle, and the gas to be treated introduced into the combustion chamber from the gas to be treated introduction nozzle and combustion from the oxidant introduction nozzle Hydrogen serving as a combustion fuel in an ignition burner that ignites a mixed gas mixed with the oxidant introduced into the chamber and in a gas supply path for supplying the gas to be processed to the gas introducing nozzle. And a hydrogen introducing part for mixing the hydrogen and the gas to be processed, and the nozzle axis of the oxidant introducing nozzle is connected to the gas introducing gas to be processed. Combustion scrubber arranged in a direction towards the extension of Le of the nozzle axis.   The combustion abatement apparatus according to claim 1, wherein the gas to be treated contains ammonia as a harmful gas component.   The combustion chamber is formed of an outer cylinder and an inner cylinder made of a gas permeable material disposed on the inner periphery of the outer cylinder, and the gas introduction nozzle and the oxidizing agent introduction nozzle are disposed in the inner cylinder. The gas to be treated and the oxidant are introduced into the formed combustion chamber, and the air introduced into the combustion chamber through the inner cylinder between the inner cylinder and the outer cylinder is outside the outer cylinder. The combustion abatement apparatus according to claim 1, wherein an air chamber supplied from is provided.   The combustion abatement apparatus according to any one of claims 1 to 3, wherein the ignition burner is a burner that is activated by a catalyst to burn.   The gas to be treated is exhaust gas discharged from a process that uses hydrogen in a part of the process. When the amount of hydrogen used in the process is small, at least a part of the hydrogen used in the process is a combustion fuel. The combustion abatement apparatus according to any one of claims 1 to 4, wherein the hydrogen is introduced from the hydrogen introduction section as hydrogen.

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