JP2688655B2 - Combustion treatment method and equipment for toxic gas - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to arsine (AsH ₃ ), phosphine (PH ₃ ),
The present invention relates to a combustion treatment method and apparatus for detoxifying a toxic gas represented by diborane (B ₂ H ₆ ) and monosilane (SiH ₄ ).

[Prior art and its problems]

From the semiconductor manufacturing process, toxic exhaust gas containing the gaseous toxic substance as described above is generated. Since such toxic exhaust gas is extremely toxic to the human body, when it is released into the atmosphere, it is necessary to completely remove toxic substances contained therein.

As one of effective methods for removing toxic substances contained in exhaust gas, a combustion method is known (Japanese Patent Application Laid-Open No. Sho 62-62).
-134414, JP-A-62-152517). This method is a method in which toxic substances in exhaust gas are oxidatively decomposed under combustion conditions, and converted into solid substances such as elemental elements and oxides to remove them.

This solid substance is also toxic and must be completely removed from the combustion gas.However, since the solid substance produced is a submicron-sized fine powder because it is produced in the gas phase, the usual solid substance is produced. Significant difficulties arise in completely removing this solid fine powder in the combustion gas from the combustion gas compared to a fine powder of several microns in size. In the above-mentioned conventional method, the produced fine powder is entrained in the exhaust gas, guided to the outside of the combustion furnace, and removed from the exhaust gas by using a wet dust remover provided outside the furnace.

That is, since the toxic gas is treated in two steps using the combustion furnace and the wet dust remover, respectively, it is not efficient and the equipment installation space becomes large. Further, the removal rate of solid fine powder in the conventional wet dust remover is not high. Furthermore, in order to collect the solid fine powder outside the combustion furnace, the fine powder must be discharged outside the furnace. However, it is difficult to completely remove the fine powder outside the furnace, and it may adhere to the solid surface such as the combustion furnace wall. Therefore, in the prior art, it is proposed to forcibly form an air flow having a relatively high linear velocity in the exhaust port direction of the combustion furnace to prevent the fine powder from adhering to the furnace wall.
However, the formation of such a high-velocity airflow is not economical, and it is difficult to completely prevent the adherence to the furnace wall, and even a small amount of fine powder adheres to the furnace wall. It Then, the adhered amount increases with the passage of time, and eventually it becomes a lump and drops irregularly from the furnace wall, and the operating conditions of the equipment, especially the pressure conditions, are changed to completely burn the toxic gas. This will result in hindrance. Further, the adhesion of fine powder to the high temperature furnace wall is not preferable because it causes the furnace wall corrosion. Furthermore, in the combustion of toxic gases such as arsine and phosphine where flame formation is difficult, if the linear velocity of the air flow is increased as described above in order to enhance the effect of discharging fine powder to the outside of the furnace, flame blow-off will occur. It is likely to occur, and there is a risk that toxic gas will be discharged to the outside of the furnace without being burnt or undecomposed.

As described above, in the conventional method, the solid fine powder generated by the combustion process of the toxic gas is discharged to the outside of the furnace together with the combustion gas, and is removed using the wet dust remover and the gas-liquid separator. In this case, the wet dust remover also serves to cool the combustion gas, and is generally a spray tower, a packed tower, a venturi scrubber, or the like.

However, in an ordinary spray tower or packed tower, although the pressure loss of the apparatus is smaller than that of the Venturi scrubber, it is very difficult to completely remove the solid fine powder. On the other hand, in the Venturi Scrubber,
The removal of solid fine powder is more efficient than the usual spray tower and packed tower, but there is a problem that the pressure loss of the apparatus becomes large. Furthermore, in these dust removers, a large amount of water is required, and a large amount of wastewater that has captured and absorbed solid fine powder is generated, which makes it difficult to treat the wastewater.

[Problem of the Invention]

The present invention solves the above problems found in the prior art, efficiently removes toxic solid fine powder generated by combustion in one device including a combustion furnace at a high removal rate, and further It is an object of the present invention to provide a toxic gas combustion treatment method and apparatus capable of substantially completely preventing solid fine powder from adhering.

[Means for solving the problem]

The present inventors have completed the present invention as a result of earnest studies to solve the above problems.

That is, according to the present invention, in a method of burning a toxic gas that produces solid fine powder by burning, a water film is formed to flow the toxic gas from the upper end to the lower end of the inner surface of the furnace wall. A solid contained in the combustion gas produced by the combustion treatment in the combustion furnace, the fine powder produced by the combustion treatment being captured and absorbed by the falling water film, and the water droplets being brought into contact with the combustion gas produced by the combustion treatment. It is characterized in that fine powder is captured and absorbed in the water droplets, and water and combustion gas that have captured and absorbed these solid fine powders are introduced into a gas-liquid separator directly connected to the bottom of the combustion furnace for gas-liquid separation. A method and apparatus for burning toxic gases are provided.

The toxic gas to be treated in the present invention generates solid fine powder by combustion treatment. Representative examples of such toxic gases include compounds of Group III to V elements of the periodic table such as arsine, phosphine, diborane, hydrogen selenide, monosilane, chlorosilane, trimethylgallium, trimethylindium, and trimethylaluminum. And those which show a gaseous state at room temperature. Such toxic gas is used in semiconductor manufacturing process, new material manufacturing process,
It is contained in the exhaust gas generated from the reaction process such as the high fiber manufacturing process. In such exhaust gas, the toxic gas content is 0.01% to 50% in volume%, and the balance consists of hydrogen gas, gases such as nitrogen and argon, etc., depending on the type of the exhaust gas. Incidentally, the toxic gas referred to in the present specification, in addition to the gas consisting of the above-mentioned gaseous toxic substance,
It means various exhaust gases including this.

Further, when the amount of combustible components in the exhaust gas is small and flame formation is insufficient, a combustible gas such as hydrogen or methane may be mixed in the exhaust gas.

When the above toxic gas is burned, solid fine powder is produced. For example, when arsine is burnt, arsenic (As) and arsenic oxide (As ₂ O ₃ ) and phosphine are burnt, and adjacent (P), phosphorous oxide (P ₂ O ₅ ) and silane are burnt. Solid fine powders such as silicon (Si) and silicon oxides (SiO, SiO ₂ ) are produced respectively. In the present invention,
The solid fine powder generated by this combustion process is captured by the water film flowing down the inner surface of the furnace wall.

When carrying out the present invention, the in-furnace gas may flow from the combustion burner toward the combustion gas outlet. The linear velocity of the gas in the furnace toward the outlet is 1 m / sec or less, preferably 0.05 m /
It is good to be below a second, More preferably, it is below 0.01 m / sec. At such a very low linear velocity in the furnace, the residence time of the solid fine powder in the furnace becomes long, the solid fine powder is in long contact with the water film surface of the inner wall of the furnace, and the inner wall water film efficiently causes the gas in the furnace Removed from. Especially when the flame is directed downward, promote the fluidization of solid fine powder by upward heat convection from the flame in the opposite direction to the gas in the furnace, increase the contact with the water film on the inner wall of the furnace, and improve the trapping efficiency. You can

In the present invention, the solid fine powder generated by this combustion treatment is captured and absorbed by water in one cylindrical device including a combustion furnace to be removed.

 Next, the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows an explanatory sectional view of a toxic gas combustion processing apparatus for carrying out the method of the present invention. This device is composed of a combustion furnace and a gas-liquid separator directly connected to the bottom of the combustion furnace, and is formed in one tubular shape as a whole. in this case,
Combustion furnace spray, packed bed, gas-liquid separator can be arranged vertically, and the installation space is minimized, which is industrially practical. In FIG. 1, the cylindrical portion A forms the combustion furnace A,
The tubular portion B forms a gas-liquid separator B.

The combustion furnace A includes a cylindrical body 1 having a ceiling portion 2, a diffusion burner 3 disposed on the ceiling portion 2, a water injection nozzle 4 disposed on the upper end portion thereof (see FIG. 2), and a lower portion thereof. Each is equipped with a water spray nozzle 5 arranged in. Further, if necessary, a part of the furnace wall in the upper part of the furnace is formed in the recess wall 6 projecting outward, the pilot burner 7 is disposed there, and an opening is formed in the counter furnace wall of this pilot burner. Is formed, the opening is sealed with the shield glass 8, and an ultraviolet ray detector is attached to the rear part. This ultraviolet ray detector comprises an ultraviolet ray detector tube 9 and a support tube 10 for supporting it.

As shown in FIG. 2, the water jet nozzle 4 arranged at the upper end of the furnace has its jet direction in the circumferential direction (tangential direction) of the tubular body 1.
The jet water becomes a swirl flow and is supplied to the inner wall surface of the furnace. By supplying such jet water, a water film 11 that flows down from the upper end portion to the lower portion is formed on the inner wall surface of the furnace.
The injection water can be formed, for example, by injecting compressed water with a pump from a nozzle, and preferably, the water is mixed with a compressed gas, and the mixture is injected tangentially to the inner wall surface of the upper end of the furnace. Can be done by doing. Air is usually used as the compressed gas.

As described above, when the jet water is introduced into the upper end of the furnace while swirling in the inner peripheral direction of the furnace, the water film can be easily formed on the inner surface of the furnace wall without being largely affected by the inclination of the furnace.
In addition, when the compressed gas is mixed and the flow velocity is increased and the water is injected, not only does the amount of water required for the injected water be small, but a water film is formed on the ceiling, and a water film is also formed on the outer peripheral surface of the burner through the ceiling. There are possible advantages. Further, by forming a water film on the outer peripheral surface of the burner, it is possible to capture and remove the solid fine powder adhering to the outer peripheral surface of the burner and the tip of the burner, and prevent the burner from being corroded or blocked by the solid fine powder. Further, in this case, by forming a water cooling jacket on the outer peripheral portion of the burner to lower the burner temperature and prevent evaporation of the water film on the outer peripheral surface of the burner, a water film can be formed on the outer peripheral surface of the burner with a smaller amount of water. You can

As the combustion burner used in the present invention, it is preferable to use a diffusion type burner. In the diffusion type burner, the toxic gas and the combustion supporting gas are mixed at the burner tip in the combustion furnace. In a pre-mixing burner that mixes toxic gas and supporting gas before entering the combustion furnace, if the toxic gas is highly reactive, the toxic gas reacts with the supporting gas in the nozzle. However, since solid content is generated, the problem of nozzle clogging occurs, which is not preferable. The basic structure of this diffusion type burner has a toxic gas flow path and a supporting gas flow path independently, and has a flammable gas flow path and an inert gas flow path as necessary. The outer periphery has a water-cooled jacket. Air or oxygen is used as the combustion supporting gas.
As the combustible gas, hydrogen, methane, propane or the like is used.

When a flammable gas flow path is interposed between the toxic gas flow path and the supporting gas flow path, diffusion mixing of the toxic gas and the supporting gas immediately after the burner outlet can be prevented. Adhesion to the burner tip is prevented. Moreover, in this case, at the tip of the burner, the combustion-supporting gas is completely consumed by the reaction with the combustible gas and does not diffuse into the toxic gas, so the reaction between the toxic gas and oxygen at the tip of the burner. Can be reliably prevented. By using an inert gas such as nitrogen gas instead of the flammable gas, it is possible to prevent the toxic gas and the combustion-supporting gas from diffusing and mixing at the burner tip, but in this case, the burner tip is used. Since it is not possible to completely prevent the reaction between toxic gas and oxygen in the burner section, when the toxic gas is at a high temperature or when burned for a long time, the solids on the burner tip are There is a problem that the adhesion of fine powder cannot be sufficiently prevented and the combustion efficiency is lowered.

 FIG. 3 shows an explanatory transverse sectional view of the diffusion type burner.

FIG. 3A is an explanatory view of a burner having a quadruple tube structure.
The first conduit 41 located in the central part forms a toxic gas nozzle, the second conduit 42 located outside thereof forms the primary combustion-supporting gas nozzle, and the third conduit 43 located outside thereof forms the secondary combustion-supporting gas nozzle. Forming a gas nozzle, the fourth conduit 44 on the outside is sealed at its tip and forms a cooling jacket.

FIG. 3B is an explanatory sectional view of a burner having a triple tube structure. The first conduit 41 located in the central part forms a toxic gas nozzle, the second conduit 42 located outside thereof forms a combustion-supporting gas nozzle, and the third conduit 43 located outside thereof has its tip sealed. To form a cooling jacket.

FIG. 3C is an explanatory sectional view of another burner having a quadruple pipe structure. A centrally located first conduit 41 forms a toxic gas nozzle and an outer second conduit 42 'forms a flammable gas nozzle and an outer third conduit 43.
Forms a combustion-supporting gas nozzle, and the fourth conduit 44 located outside thereof is sealed at its tip to form a cooling jacket.

FIG. 3D is an explanatory cross-sectional view of yet another burner having a quadruple pipe structure. A centrally located first conduit 41 'forms a flammable gas nozzle and an outer conduit 42' forms a toxic gas nozzle and an outer conduit 43 '.
Is the conduit that forms the flammable gas nozzle and is located outside it
44 'forms a combustion-supporting gas nozzle.

FIG. 3 (e) is an explanatory view of a burner having a structure in which a plurality of conduits are inserted in the central portion of the double pipe. Multiple conduits in the center
41 is a conduit 45 forming a toxic gas nozzle and surrounding it
Is a combustible gas nozzle, and the conduit 42 located outside thereof is a combustible gas nozzle.

In the combustion furnace A of the apparatus shown in FIG. 1, the spray nozzle 5 arranged on the lower wall of the furnace injects water droplets into the furnace to collide with the combustion gas to rapidly cool the combustion gas. The inner wall water film is also provided to remove the solid fine powder in the combustion gas. That is, by rapidly cooling the combustion gas, the water vapor in the gas is condensed with the solid fine powder as nuclei to form water droplets, and the solid fine powder is taken up and removed in the water droplets. The solid fine powder is taken into and removed by the water droplets due to the collision with. This water droplet injection makes it possible to efficiently remove the solid fine powder in the furnace together with the water film on the inner wall of the furnace.

Further, as shown in FIG. 4, an ignition plug 12 is arranged together with the pilot burner 7 on the recess wall 6 in the upper part of the furnace. The outer peripheral surface of the spark plug 12 is made of an insulator, and the distance a between the insulator surface and the recess wall surface and the distance b between the insulator surface and the outer surface of the pilot burner are kept at least about several mm. Has been done. It is preferable that the tip discharge portion of the spark plug is formed in a hook shape as shown in FIG. When arranging the pilot burner and the spark plug in this way, it is avoided that the tip part of the pilot burner and the tip part of the spark plug are connected by a water film, and a short circuit between the spark plug and the pilot burner or other than the spark plug A spark is prevented from being generated at this location. Moreover, on the surfaces of the pilot burner and the spark plug, water droplets drop from the furnace wall surface on which the water film is formed, wet the surfaces of the pilot burner and the spark plug, and the solid particles on the pilot burner and the spark plug are wetted. Powder adhesion is prevented. If solid fine powder adheres to the tip of the pilot burner or the tip of the spark plug, it causes inconvenience such as difficulty in ignition of the pilot burner. However, by disposing the pilot burner as described above, such inconvenience occurs. Is prevented, and reliable ignition can be obtained. Further, gas such as air may be introduced into the insulator portion of the ignition plug 12 to dry the insulator portion. As flammable gas for pilot burner,
Hydrogen gas is preferably used. Compared to the use of combustible gases such as methane and propane, the use of hydrogen gas expands the combustion range (mixing ratio, linear velocity), and allows the pilot burner to be downsized. It has the advantage that no blowout of

The ultraviolet ray detection device arranged on the upper wall of the furnace via the shield glass 8 detects the presence or absence of flame in the pilot burner. In the case of the present invention, the shield glass is washed with a water film, solid fine powder is prevented from adhering, and flame detection can be reliably performed.

In FIG. 1, a gas-liquid separator B directly connected to the bottom of the combustion furnace A is provided in a cylinder 21, a combustion gas exhaust pipe 22 arranged above the cylinder 21, and a liquid reservoir 26 at the bottom thereof. Drain pipe
23, and further, a filling layer 24 is provided in the cylinder.

The gas-liquid separator B may basically have a structure capable of separating the water and the combustion gas, which have captured and absorbed the solid fine powder generated in the combustion furnace A, into which the packed bed 24 is arranged. Is not necessarily required. However, when the packed bed 24 is provided, sufficient gas-liquid contact between the combustion gas and water is achieved in this packed bed, so that the residual solid fine powder is contained in the combustion gas from the combustion furnace A. In addition, it is possible to easily remove the toxic solid fine powder that is captured and absorbed by the water that comes into contact therewith and that remains in the combustion gas discharged from the combustion furnace. Therefore, in this case, the solid fine powder contained in the combustion gas does not necessarily have to be completely removed in the combustion furnace, so the amount of water used in the combustion furnace A can be small, and the operating conditions of the combustion furnace are The combustion furnace itself can be downsized as well as being remarkably relaxed.

The structure of the packed bed 24 is arbitrary, and any structure may be used as long as it allows gas-liquid contact between the combustion gas from the combustion furnace A and water. For example, a filling layer may be provided on the upper part of the cylindrical body 21, a space below the filling layer may be provided, and a liquid reservoir 26 may be provided below the space. In this case, the drainage pipe 23 is provided in the liquid reservoir at the bottom thereof, and the exhaust pipe 22 is provided in the space portion in the middle thereof.

A packing layer suitable for use in the present invention is as shown in FIG.
The upper part of the packed bed has a shape capable of confluently mixing the water film flowing down the inner surface of the furnace wall and the falling water droplets formed by the spray nozzle, for example, a downward conical shape, and the lower part of the liquid reservoir part 26 downward. The structure has a pillar shape extending to the upper part, and a space 25 is arranged outside the pillar. When the packed bed having such a structure is used, the gas-liquid mixed phase flow collides with the water surface of the liquid reservoir 26 from the lower end of the column-shaped packed bed, so that the gas-liquid separation can be efficiently performed. Further, since fine bubbles generated by the flow of the gas-liquid mixed phase flow from the upper part to the lower part of the packed bed are ejected from the lower end of the packed bed to form a bubble layer on the water surface, the kinetic energy of the gas in the bubbles causes Efficient contact between the bubbles and the water film enclosing the gas phase is obtained, and as a result, the solid fine powder contained in the gas is efficiently captured and absorbed in water.
In this case, all or part of the space 25 outside the packed bed 24 may be a packed bed separately from the packed bed 24, and water may be supplied to the upper part of this packed bed to perform gas-liquid contact again. This can further increase the capture rate of the solid fine powder.

As the packing material used for forming the packing layer, a general packing material used for gas-liquid contact (for example, Raschig ring, ball, etc.) can be used, but in the case of the present invention, a normal rectification column It is preferable to use a packing material that can be efficiently contacted with gas and liquid as used in, for example, a small piece (size: about 5 to 30 mm) of a wire mesh of 10 to 100 mesh. The small pieces of wire mesh are preferably used in the shape of a cylinder, a saddle, or the like. When a gas-liquid multiphase flow is passed from the top to the bottom of the packed bed of the wire mesh, the liquid is evenly dispersed on the wire mesh surface to form a liquid film, and the combustion gas passes through the liquid film. Liquid contact occurs, and at the same time a large amount of fine bubbles are generated. Then, in this bubble, the gas moves violently due to the kinetic energy of the gas in the bubble, so that efficient contact with the liquid film surrounding the gas can be obtained. In this way, the pressure loss can be reduced, and the solid fine powder in the combustion gas can be efficiently transferred to the water phase and removed.

Further, in order to perform gas-liquid separation in the cylindrical body 21, water and combustion gas from the combustion furnace A are collected by a funnel-shaped collection pipe, and this is bubbled into water in the liquid reservoir 26 to make gas-liquid contact. It is also possible to separate the combustion gas from the water and to exhaust this to the outside of the system.

Next, a specific example in which the present invention is carried out using the apparatus shown in FIG. 1 will be described.

First, the liquid reservoir 26 is filled with water, and this water is injected from the upper end of the combustion furnace A through the drain pipe 23, the pump 32, the conduit 36 and the conduit 38 in the inner circumferential direction of the furnace together with the pressurized air from the conduit 39. Then, water is jetted from the spray nozzle 5 into the furnace through the conduit 37. A water film flowing down is formed on the inner wall surface of the furnace by the water jet from the upper end of the furnace. In this case, a water film can be formed on the ceiling part of the furnace by inclining the water injection direction slightly upward, and a water film is also formed on the outer peripheral surface of the burner 3 through the water film on the ceiling part. can do.

Next, in the pilot burner 7, hydrogen gas is combusted with air to form a hydrogen flame, and the fourth end-sealing of the burner 3 (see the diffusion burner having the quadruple tube structure shown in FIG. 3A) is performed.
Water is introduced into the conduit 44 to form a water cooling jacket, with secondary oxygen in the third conduit 43, primary oxygen in the second conduit 42 and first conduit 41.
Toxic gases are introduced into the fuel cell, and these gases are ejected from the burner tip, ignited by the hydrogen flame of the pilot burner, and burned. By burning the toxic gas in this manner, solid fine powder is produced.
It is captured and absorbed by the water film formed on the furnace wall, and also captured and absorbed by the water droplets ejected from the spray nozzle 5. Then, the water and the combustion gas that have captured and absorbed the solid fine powder are sent to the gas-liquid separator B directly connected to the solid fine powder, and the solid fine powder remaining in the combustion gas is further captured by the packed bed, and then separated into gas and liquid. .

That is, the water that flows down as a water film on the inner surface of the furnace wall, the water that drops as water droplets formed by the spray from the spray nozzle, and the combustion gas are combined and mixed at the upper part of the packed bed 24,
It passes through the packed bed as a gas-liquid mixed phase flow, and is jetted from the lower end of the packed bed onto the water surface of the liquid reservoir 26 as a gas-liquid mixed phase flow containing bubbles, where it is separated into gas and liquid. The separated combustion gas is discharged from the space 25 through the exhaust pipe 22 to the outside of the system.

The water in the liquid reservoir 26 is circulated through the drain pipe 23 to the upper end of the combustion furnace by the pump 32, and the circulating water is cooled to a predetermined temperature (about 30 ° C.) by the cooler 34.

The water level of the liquid reservoir 26 is maintained at a constant water level by a water level gauge 35 and a water level control valve 33 attached to a conduit 31 'connected to the drain tank 31. That is, in the combustion process of toxic gas, water is by-produced, and this by-product water forms surplus water in the system. This surplus water is stored in the tank 31 through the line 31 'by the water level gauge 35 and the water level control valve 33.

In the present invention, almost all of the solid fine powder generated by the combustion process of the toxic gas can be captured and absorbed by water in the device.

When carrying out the present invention, the linear velocity of the in-furnace gas going from the upper side to the lower side in the furnace is preferably 1 m / sec or less, and more preferably 0.05 m / sec or less. At such a very low linear velocity of the gas in the furnace, the solid fine powder is in long contact with the wall surface of the furnace and is efficiently removed from the gas in the furnace by the water film on the wall of the furnace.

〔The invention's effect〕

According to the present invention, in the combustion furnace A, the solid fine powder generated by the combustion process of the toxic gas is captured and absorbed by the water film formed on the inner surface of the furnace wall, and is also brought into contact with the combustion gas. It is captured and absorbed by water droplets from the. Furthermore, the gas-liquid contact in the gas-liquid separator B is also captured and absorbed in water. Furthermore, a packed bed can be installed in the gas-liquid separator to increase the gas-liquid contact rate and to capture and absorb the solid fine powder. Therefore, according to the present invention, the amount of the fine solid powder discharged to the outside of the furnace together with the combustion gas can be made extremely small, and in some cases, can be made substantially zero. Therefore, in the present invention, a small filter is provided outside the furnace, and the combustion gas can be made completely harmless by passing through this filter.

INDUSTRIAL APPLICABILITY The apparatus of the present invention can be downsized by directly connecting a combustion furnace, a packed bed, and a gas-liquid separator in a vertical type, and the installation space is extremely small, which is highly industrially practical.

Further, the formation of the water film on the combustion furnace wall is very advantageous in terms of cooling the furnace wall and preventing corrosion.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

Example 1 A toxic gas combustion treatment was performed using the apparatus shown in FIG. In this case, a gas composed of 5% by volume of phosphine (PH ₃ ) and 95% by volume of hydrogen gas was used as the toxic gas.

In the device shown in FIG. 1, water from conduit 36 and conduit
A mixture with air from 39 is injected in the circumferential direction from the top of the combustion furnace A to form a falling water film on the furnace wall, and hydrogen is burned by the pilot burner 7 to form a hydrogen flame,
Then, water was ejected from the spray nozzle 5 to disperse water droplets in the furnace. Further, the water in the liquid reservoir 26 of the gas-liquid separator B was circulated through the conduit 38 and reused as shown in FIG. The filling layer 24 was formed by filling a funnel-shaped support member with a saddle-type wire mesh (mesh: 48, size: 15 mm), and disposing the same in the gas-liquid separation cylinder 21.

Next, in order to burn the toxic gas, primary oxygen is introduced into the furnace through the conduit 42 of the diffusion burner 3 (see FIG. 3 (a)), and secondary oxygen is introduced into the furnace through the conduit 43. The toxic gas was introduced into the furnace through the conduit 41 and burned. Further, water was charged into the conduit 44 with the tip sealed to form a water cooling jacket.

 Next, specific operating conditions will be described.

[Combustion conditions]

(1) Toxic gas (conduit 15, conduit 41) Flow rate: 12Nl / min (2) Primary oxygen (conduit 42) Flow rate: 6Nl / min (3) Secondary oxygen (conduit 43) Flow rate: 10Nl / min [Water Film formation conditions] (1) Circulating water amount (conduit 36): 7 / min (2) Air amount (conduit 39): 5 / min [Water droplet forming conditions] (1) Fountain amount (spray nozzle 5): 19 / min [ Pilot burner operating conditions] (1) Hydrogen gas flow rate: 2.5 Nl / min Air amount: 2.5 Nl / min As a result of burning the toxic gas as described above, the combustion gas discharged from the exhaust pipe 22 contains phosphine. Was not detected at all (less than 1PPb). In addition, the solid fine powder (P ₂ O ₅ ) contained in the combustion gas was measured, and the solid fine powder removal rate in the equipment was calculated from this measured amount and the solid fine powder production amount based on the total toxic gas treatment amount. As a result of the calculation, a P ₂ O ₅ removal rate of 98.6% is obtained.

Further, after the completion of the combustion treatment test (100 hours after the start of the test), the presence or absence of solid fine powder on the burner tip and the inner wall of the furnace was examined, and no solid fine powder was found to be deposited.

Example 2 In Example 1, monosilane (Si
The same experiment was conducted except that a mixture of 5% by volume of H ₄ ) and 95% by volume of hydrogen gas was used, and the amount of air from the conduit 39 was changed to 40 / min. As a result, monosilane was not detected at all in the combustion gas discharged from the exhaust pipe 22 (0.1 ppm or less). Alternatively, the removal rate of solid fine powder in the apparatus was 93.4%.

Example 3 In Example 1, as a toxic gas, arsine (As
The experiment was conducted in exactly the same manner except that 2% by volume of H ₃ ) and 98% by volume of hydrogen were used. As a result, no arsine was detected in the combustion gas discharged from the exhaust pipe 22 (4 PPb or less), and the solid fine powder (AS ₂ O ₃ ) removal rate in the device was 9%.
It was 8.1%.

Example 4 An experiment was conducted in the same manner as in Example 1 except that the air amount from the conduit 39 was changed to 40. As a result, also in this case, no phosphine was detected in the combustion gas discharged from the exhaust pipe 22, and the removal rate of the solid fine powder (P ₂ O ₅ ) in the apparatus was 96.6%.

Example 5 As a result of conducting an experiment in the same manner as in Example 4 except that the packed bed was not used, no phosphine was detected in the combustion gas discharged from the exhaust pipe 22, and the solid fine powder (P _{The 2} O ₅ ) removal rate was 90.8%.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of an apparatus for carrying out the method of the present invention, and FIG. 2 is an arrangement explanatory view of an injection nozzle arranged at the upper end of the furnace. 3 (a) to 3 (e) are explanatory transverse sectional views of the tip of the combustion burner. FIG. 4 is an enlarged view of the recessed furnace wall portion provided with the pilot burner. 1 ... Combustion furnace cylinder part, 2 ... Furnace ceiling part, 3 ... Combustion burner, 4 ... Water injection nozzle, 5 ... Water spray nozzle,
6 ... Recessed furnace wall, 7 ... Pilot burner, 8 ... Shield glass, 9 ... UV detector tube, 11 ... Water film, 21 ...
Gas-liquid separation cylinder, 22 ... Exhaust pipe, 23 ... Drain pipe, 24 ...
… Packed bed, 25 …… Space, 26 …… Liquid reservoir, 31 …… Water tank, 32 …… Pump, 34 …… Cooler, 35 …… Water level gauge, 36
...... Water level control valve.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F23J 15/04 F23J 15/00 D (72) Inventor Munekazu Nakamura Imai-cho, Hodogaya-ku, Yokohama-shi, Kanagawa 220-17 (72) Inventor Chiaki Kojima 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Kunio Kaneko 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Yoshifumi Mori 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Hideto Ishikawa 6-35 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation (56) References JP-A-62-134414 (JP, A) JP-A-56-34017 (JP, A) Actually-laid-open Sho-50-126742 (JP, U) JP-B-63-2204 (JP, B2)

Claims (9)

(57) [Claims] 1. A method of burning a toxic gas for producing a solid fine powder by the burning process, wherein the toxic gas is
Combustion treatment is performed in a combustion furnace in which a water film flowing down from the upper end to the lower end of the inner surface of the furnace wall is formed, and solid fine powder produced by the combustion treatment is captured and absorbed by the falling water film,
Water droplets are brought into contact with the combustion gas generated by the combustion treatment to capture and absorb the solid fine powder contained in the combustion gas into the water droplets. A method for combustion treatment of toxic gas, characterized by leading to a gas-liquid separator that is directly connected to the bottom of the tank to separate gas-liquid. 2. The method according to claim 1, wherein water and combustion gas which have captured and absorbed the solid fine powder are brought into gas-liquid contact through a packed bed, and then gas-liquid separation is performed. 3. The method of claim 1 or 2 wherein the packed bed is formed from pieces of wire mesh of 10 to 100 mesh. 4. The method according to claim 1, wherein the water separated by the gas-liquid separator is reused again for forming the water film and water droplets. 5. A vertical combustion furnace and a gas-liquid separator directly connected to the bottom of the combustion furnace. The combustion furnace has a diffusion burner at its ceiling and water directed in the circumferential direction at its upper end. A toxic gas combustion treatment apparatus, comprising: an injection nozzle and a water spray nozzle at a lower portion thereof; and the gas-liquid separator having a combustion gas exhaust pipe at an upper portion thereof and a drain pipe at a lower portion thereof. 6. The apparatus according to claim 5, wherein a packed bed is installed inside the gas-liquid separator. 7. The apparatus of claim 6, wherein the top of said packed bed is downwardly conical and the bottom thereof is downwardly extending post-shaped. 8. A device according to claim 6 or 7, wherein the packed bed is formed from pieces of wire mesh of 10 to 100 mesh. 9. A drainage pipe of the gas-liquid separator is connected to a water injection nozzle at the upper end of the combustion furnace and a water spray nozzle at the lower part of the combustion furnace via a pump. apparatus.