JP2011062697A - Method for removing halogen gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for removing a halogen gas which suppresses ignition of an adsorbent, is high in throughput of the halogen gas, and reduces an odor of a used adsorbent and generation of solid wastes. <P>SOLUTION: Hydrogen carbonate having an average particle size of a primary particle of 10 to 500 μm is granulated, and the obtained granule containing the hydrogen carbonate (provided except sodium hydrogencarbonate) of 70 mass% or more is brought into contact with the halogen gas at temperatures of 50°C or higher and also at less than 80°C to remove it. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for removing a halogen-based gas composed of a halogen simple substance or a halogen compound, for example, a method for removing a halogen-based gas from a dry etching exhaust gas containing a halogen-based gas.

  Conventionally, as a method for treating dry etching exhaust gas containing halogen-based gas composed of a single halogen or a halogen compound or exhaust gas in a CVD (chemical vapor deposition) chamber, activated carbon has been used for downsizing equipment and simplifying operation. A dry processing method using an adsorbent such as the above is adopted. However, since the adsorption capacity of the activated carbon is small, the treatment time is short, ignition due to adsorption heat during gas adsorption, odor of used adsorbent, generation of solid waste, and the like.

  In view of the above problems, the present invention suppresses the ignition of the adsorbent, has a high halogen-based gas processing capacity, reduces the odor of the used adsorbent and the generation of solid waste, and has a low frequency of replacement of the adsorbent. A method for removing a halogen-based gas is provided.

  The present invention granulates a hydrogen carbonate powder having an average primary particle diameter of 10 to 500 μm, and the resulting granulated product containing 70% by mass or more of a hydrogen carbonate (excluding sodium hydrogen carbonate), Provided is a halogen-based gas removal method in which a halogen-based gas is removed by contact with a halogen-based gas comprising a halogen alone or a halogen compound at a temperature of 50 ° C. or higher and lower than 80 ° C.

  According to the present invention, as a remover capable of adsorbing a single halogen or a halogen compound, a granulated product that does not powder during use, has a high removal capability, and generates little odor is obtained. Further, the granulated product of the present invention can be applied as it is to a packed tower using conventional activated carbon. In the present invention, by setting the temperature of the halogen-based gas to 50 ° C. or more and less than 80 ° C., the halogen-based gas removal ability of the granulated product can be enhanced, and the effect of the granulated product can be maintained for a long time.

  In the present invention, as the hydrogen carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate and the like can be used. In particular, sodium hydrogen carbonate is preferred because it is industrially suitable because it can be obtained in large quantities and at a low price, and it is not hygroscopic and can be easily used in the production and storage of a granulated product. On the other hand, potassium bicarbonate is preferable when it is desired to prevent sodium from being mixed into the exhaust gas after the removal treatment.

  In the present invention, the bicarbonate powder is granulated. The granulated product preferably contains 70 mass% or more of hydrogen carbonate. If the hydrogen carbonate is less than 70% by mass in the granulated product, the gas treatment capacity as the halogen-based gas removal agent is reduced, and the frequency of replacement of the removal agent packed bed is increased, which is not preferable. The content of the bicarbonate is particularly preferably 80% by mass or more. In addition, in the granulated material, examples of other materials include adsorbents other than bicarbonates, binders, and the like.

  In the present invention, the hydrogen carbonate powder having a primary particle average particle size of 10 to 500 μm is used. If the average particle size of the primary particles is less than 10 μm, it is not preferable because the fluidity is poor and handling such as handling becomes difficult, and if it exceeds 500 μm, it is technically difficult to produce a granulated product, which is costly. It is not preferable because it becomes too high. The primary particles are single crystals of hydrogen carbonate, and the average particle size is the average particle size based on weight.

  In the present invention, the average particle size of the granulated product of the bicarbonate powder is 0.5 to 20 mm. When the granulated product has an average particle size of 0.5 to 20 mm, a conventionally used packed tower or the like can be used in the treatment of the halogen-based gas. When the average particle size of the granulated product is less than 0.5 mm, the pressure loss when the halogen-based gas or the gas to be treated containing it passes through the packed bed or the like becomes high, and the average particle size exceeds 20 mm. The contact area between the gas to be treated and the granulated product is reduced, and the exhaust gas removal performance is reduced. The average particle size of the granulated product is particularly preferably 0.5 to 10 mm.

  In the present invention, the average particle size of the granulated product is measured by the following method. Overlay sieves in the range corresponding to the particle size of the granulated product, place a bottom pan at the bottom, pour the granulated product from the top, shake it with a shaker, and then use each standard sieve. The mass of the upper residue is measured, and the total mass of the residue on the sieve with respect to each opening value is represented by a line graph. The particle diameter when the total mass of the residue on the sieve is 50% is defined as the average particle diameter. Although the difference between the openings of the upper and lower sieves depends on the particle diameter of the granulated product, it is preferable to use a pitch of 0.5 mm.

  In the present invention, the granulated product can be obtained by various methods such as a compression molding method, an extrusion molding method, a rolling granulation method, and a stirring granulation method. Here, the compression molding method is industrially simple because the process is simple, and it is possible to obtain a granulated product without using a binder, and it is hard to break and has a large gas processing capacity. Since a granular material can be obtained, it is especially preferable.

  As a method for obtaining the granulated product, for example, a method of using a compression molding machine, dry molding, coarse pulverization, and sieving may be mentioned. Moreover, the method of shape | molding with a wet compression molding machine using a water-soluble binder, and making it dry after that is also mentioned.

  In the present invention, when a granulated product of a bicarbonate powder is used in a packed bed to treat a halogen-based gas, if the strength is low, it is pulverized and passes through the packed bed. Pressure loss may increase. For this reason, the strength of the granulated product is increased.

  Hardness is mentioned as a strength evaluation method of the granulated product in the present invention. Here, the hardness is a force required to compress and destroy one of the granulated particles by applying a load vertically from above.

  The evaluation method of hardness in the present invention is performed on a particle group in which the granulated particles are classified according to the average particle diameter and the particle diameters are uniform. For example, a granulated product having an average particle diameter of 1.5 mm or more and less than 2.0 mm is sieved using a sieve having an average opening of 1.5 mm and a sieve having an opening of 2.0 mm, Collect 20 particles under 0.0 mm sieve, measure the hardness of each particle, and adopt the average value as an evaluation standard of particle strength.

  As the hardness of the granulated product of the bicarbonate powder of the present invention, in the case of a granulated product having an average particle size of 0.5 mm or more and less than 1.0 mm, the granulated product having a particle size of 0.5 mm or more and less than 1.0 mm is used. In the case of a granulated product having an average hardness of 1N or more and an average particle size of 1.0 mm or more and less than 1.5 mm, the average hardness of the granulated product having a particle size of 1.0 mm or more and less than 1.5 mm is 4N or more, and the average In the case of a granulated product having a particle size of 1.5 mm or more and less than 2.0 mm, the average hardness of the granulated product having a particle size of 1.5 mm or more and less than 2.0 mm is 10 N or more, and the average particle size is 2.0 mm or more and 20 mm or less. In the case of a granulated product, the average hardness of the granulated product having a particle diameter of 2.0 mm or more and 20 mm or less is preferably 30 N or more.

In the present invention, a halogen-based gas composed of a single halogen or a halogen compound is removed. For example, a dry etching exhaust gas containing a halogen gas is treated to remove the halogen gas in the exhaust gas. Examples of halogen include fluorine, chlorine, bromine and the like. Specific halogens or halogen compounds are selected from BCl ₃ , CCl ₄ , Cl ₂ , SiCl ₄ , HCl, COCl ₂ , F ₂ , SiF ₄ , HF, COF ₂ , NF ₃ , WF ₆ , ClF ₃ and HBr. 1 type or 2 types or more mentioned. In addition to this it includes _{I 2.}

  In the present invention, the reactivity of the granulated product is enhanced by setting the temperature of the halogen-based gas composed of a single halogen or a halogen compound to 40 ° C. or more and less than 80 ° C., and can be efficiently removed, and the effect of the granulated product is also achieved. Long lasting. The halogen-based gas may be directly set to a temperature of 40 ° C. or higher and lower than 80 ° C., and a packed tower or the like packed with the granulated product may be set to 40 ° C. or higher and lower than 80 ° C. If the temperature of the halogen-based gas is less than 40 ° C., the reaction rate decreases, which is not preferable. Further, if it exceeds 80 ° C., it is necessary to make the equipment such as a packed tower as an expensive heat-resistant material or structure, and it is not preferable because handling work becomes difficult. The temperature of the halogen-based gas is particularly preferably 50 ° C. or higher and lower than 70 ° C.

  In the present invention, the bicarbonate reacts with a halogen alone or a halogen compound to produce a water-soluble salt. Since the bicarbonate itself is water-soluble, the granulated product after being used for removing the halogen-based gas in the exhaust gas can be dissolved in water. Moreover, as will be described later, for example, when hydrogen carbonate and activated carbon are used in combination, solid waste can be reduced.

  Since hydrogen carbonate reacts with halogen alone or with a halogen compound to produce a water-soluble salt, the halogen alone or halogen compound is not eliminated and no odor is generated as in the case of activated carbon adsorption. Replacing layers can be done easily. In addition, there is no risk of ignition because the hydrogen carbonate itself is extinguisher.

  In the present invention, it is also preferable to remove the halogen-based gas by filling the granulated product together with activated carbon into a container such as a packed tower and contacting with the halogen-based gas. By this method, compared to the case where activated carbon is used alone, not only the amount of halogen alone or halogen compound removed can be increased, but also the generation of odor from activated carbon can be reduced. Specifically, the hydrogen carbonate and the activated carbon are used by arranging them in a layer in a container such as a packed tower.

  In each of the following examples, the hardness and average particle diameter were measured by the following methods.

  The hardness was measured using a Kiya type digital hardness meter KHT-20 manufactured by Fujiwara Seisakusho. Further, since the hardness varies depending on the size of the particles, the particle diameters were made by sieving.

  The average particle size was measured by the following method. 100 g of powder sample was overlapped with a standard sieve (inner diameter: 200 mm, made of wire mesh stainless steel) with mesh openings of 5.60 mm, 4.75 mm, 4.00 mm, 2.80 mm, 2.00 mm and 1.00 mm, respectively. After pouring on the bottom plate installed at the bottom and shaking for 10 minutes with Iida Seisakusho's low-tap shaker type shaker (frequency 60 Hz, 290 rpm / min, 165 strokes / min), each standard sieve The mass of the upper residue was measured, and the cumulative amount of passing mass for each opening value was shown in a graph. The particle size when the cumulative amount of passing mass was 50% was defined as the average particle size.

  [Example 1] 300 kg of powdered sodium bicarbonate powder for food additives (produced by Asahi Glass Co., Ltd.) having an average primary particle size of 91 μm is roll-pressed compression molding machine (trade name: Roller Compactor WP, roll Compressive molding was performed at a linear pressure of 36.8 kN / cm using an outer diameter of 230 mm and a roll length of 80 mm to obtain a flaky sodium bicarbonate powder compact. The obtained flaky shaped product was roughly crushed with a flake breaker, and the mesh of the rotary granulator was set to 4.75 mm and allowed to pass through all. Screener TS type) is used to remove particles with a particle size of 4.0 mm or more and particles with a particle size of 1.0 mm or less to obtain a granulated product of sodium bicarbonate powder having an average particle size of 2.3 mm. It was.

  Further, the particle strength of the granulated product was measured by the above-described hardness measurement method. That is, the obtained granulated product having an average particle diameter of 2.3 mm is sieved with a sieve having an opening of 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, and 2.5 mm, and the hardness of each particle size is 20 pieces. When the average value was determined by measurement, the average hardness of particles of 0.5 mm or more and less than 1.0 mm was 4N, 1.0 mm or more and less than 1.5 mm was 12N, 1.5 mm or more and less than 2.0 mm was 23N, 2.0 mm The above was 63N.

Next, 30 kg of the granulated product was filled as a filling material in a filling vessel made of stainless steel with a fluororesin lining having a bottom surface of a breathable sintered plate and an inner diameter of 300 mm and a length of 1300 mm. As a gas to be treated, a gas having a composition ratio in a standard state of BCl ₃ : 20% by volume, Cl ₂ : 60% by volume, and argon: 20% by volume is heated to a flow rate of 200 cm ³ / min and a temperature of 60 ° C. And injected from the bottom of the filling container. When the gas flowing out from the upper part of the filling container was analyzed, BCl ₃ was not detected and the Cl ₂ concentration was 0.1 volume ppm or less.

After 361 hours from the start of the treatment, the Cl ₂ concentration in the effluent gas began to rise exceeding 0.1 ppm by volume. When the filler was taken out, the granulated particles were not pulverized and no odor was generated. Moreover, when this filler was dissolved in water, it was completely dissolved, and no solid waste was generated.

[Example 2 (Comparative Example)] The test was performed in the same manner as in Example 1 except that the temperature of the gas to be treated was changed to 25 ° C. When the effluent gas was analyzed in the same manner as in Example 1, BCl ₃ was not detected, and the Cl ₂ concentration was 0.1 ppm by volume or less.

After 309 hours from the start of the treatment, the Cl ₂ concentration in the effluent gas began to rise above 0.1 ppm by volume. When the filler was taken out, the granulated particles were not pulverized and no odor was generated. Moreover, when the granulated material was dissolved in water, all of the filler was dissolved. Compared with Example 1, the effective time of sodium hydrogen carbonate was short because the reaction efficiency of sodium hydrogen carbonate was deteriorated.

[Example 3 (Comparative Example)] A test was performed in the same manner as in Example 1 except that 30 kg of sodium bicarbonate to be filled was changed to 30 kg of activated carbon. When the effluent gas was analyzed in the same manner as in Example 1, BCl ₃ was not detected, and the Cl ₂ concentration was 0.1 ppm by volume or less.

After 187 hours from the start of the treatment, the Cl ₂ concentration in the effluent gas began to rise above 0.1 ppm by volume. When the filler was taken out, activated carbon particles were not pulverized, but generation of chlorine odor was observed.

[Example 4] A test was conducted in the same manner as in Example 1 except that the gas was not directly heated to 60 ° C, but the filling container itself was heated to 70 ° C by an electric heater. When the effluent gas was analyzed in the same manner as in Example 1, BCl ₃ was not detected, and the Cl ₂ concentration was 0.1 ppm by volume or less.

After 362 hours from the start of the treatment, the Cl ₂ concentration in the effluent gas began to rise exceeding 0.1 ppm by volume. When the filler was taken out, the granulated particles were not pulverized and no odor was generated. Moreover, when the granulated material was dissolved in water, all of the filler was dissolved.

[Example 5] A test was conducted in the same manner as in Example 1 except that the inside of the filling container filled with sodium hydrogen carbonate was depressurized to 2.7 kPa. When the effluent gas was analyzed in the same manner as in Example 1, BCl ₃ was not detected, and the Cl ₂ concentration was 0.1 ppm by volume or less.

After 355 hours from the start of the treatment, the Cl ₂ concentration in the effluent gas began to rise exceeding 0.1 ppm by volume. When the filler was taken out, the granulated particles were not pulverized and no odor was generated. Moreover, when the granulated material was dissolved in water, all of the filler was dissolved.

[Example 6] 20 kg of a granulated product of sodium hydrogencarbonate obtained in the same manner as in Example 1 and 10 kg of activated carbon were charged in the same filled container. As the gas to be treated, the composition ratio in the standard state is BCl ₃ : 20% by volume, CCl ₄ : 0.6% by volume, Cl ₂ : 41.1% by volume, SiCl ₄ : 0.6% by volume, HCl: 4. 8% by volume, COCl ₂ : 0.6% by volume, F ₂ : 2.7% by volume, SiF ₄ : 0.6% by volume, HF: 4.8% by volume, COF ₂ : 0.6% by volume, NF ₃ Example 1 except that 0.8% by volume, WF ₆ : 0.6% by volume, ClF ₃ : 0.6% by volume, HBr: 4.8% by volume, and argon: 20.0% by volume were used. In the same manner as above, the test was performed with the temperature of the gas to be treated set at 60 ° C. When the effluent gas was analyzed in the same manner as in Example 1, the Cl ₂ concentration was 0.1 ppm by volume or less, and other than BCl ₃ , CCl ₄ , SiCl ₄ , HCl, COCl ₂ , F ₂ , SiF ₄ , _{HF, COF 2, NF 3,} WF 6, ClF 3, HBr and the like were not detected.

After 301 hours from the start of the treatment, the Cl ₂ concentration in the effluent gas began to rise exceeding 0.1 ppm by volume. When the filler was taken out, the granulated particles were not pulverized and no odor was generated. Moreover, when this granulated material was melt | dissolved in water among the fillers, 90 mass% or more melt | dissolved.

Example 7 (Comparative Example) The test was conducted in the same manner as in Example 6 except that the temperature of the gas to be treated was changed to 25 ° C. When the effluent gas was analyzed in the same manner as in Example 6, the Cl ₂ concentration was. Other than BCl ₃ , CCl ₄ , SiCl ₄ , HCl, COCl ₂ , F ₂ , SiF ₄ , HF, COF ₂ , NF ₃ , WF ₆ , ClF ₃ , HBr, etc. other than argon are not detected. It was.

After 268 hours from the start of the treatment, the Cl ₂ concentration in the effluent gas began to rise exceeding 0.1 ppm by volume. When the filler was taken out, the granulated particles were not pulverized and no odor was generated. Moreover, when this granulated material was melt | dissolved in water among the fillers, 90 mass% or more melt | dissolved. Compared with Example 6, the effective time of sodium hydrogen carbonate was short because the reaction efficiency of sodium hydrogen carbonate was poor.

[Example 8 (Comparative Example)] Test was conducted in the same manner as in Example 6 except that sodium hydrogen carbonate was used as activated carbon. When the effluent gas was analyzed in the same manner as in Example 6, the Cl ₂ concentration was 0.1 ppm by volume or less, and other than BCl ₃ , CCl ₄ , SiCl ₄ , HCl, COCl ₂ , F ₂ , SiF ₄ , _{HF, COF 2, NF 3,} WF 6, ClF 3, HBr and the like were not detected.

After 184 hours from the start of the treatment, the Cl ₂ concentration in the effluent gas began to rise exceeding 0.1 ppm by volume. When the filler was taken out, activated carbon particles were not pulverized, but generation of chlorine odor was observed.

  [Example 9] 25 kg of sodium hydrogen carbonate powder for food additives (manufactured by Asahi Glass Co., Ltd.) having an average primary particle size of 56 μm is placed in a kneader (trade name: batch kneader KDHJ-100, manufactured by Fuji Powder Co., Ltd.) As a binder, 3.75 kg of a 2% by weight aqueous solution of carboxymethylcellulose for food additives (trade name: F-20, manufactured by Nichirin Chemical Industry Co., Ltd.) was sprayed as a binder. This was granulated using a solid disk die roll type disk pelleter (trade name: disk pelleter F-40, manufactured by Fuji Powder Corporation). The obtained granulated product was granulated into a spherical shape by a spherical granulator (trade name: Malmerizer Q-400, manufactured by Fuji Powder Co., Ltd.) to obtain a spherical granulated product. Next, this granulated material was allowed to stand and dry at a temperature of 60 ° C. for 12 hours in a carbon dioxide gas atmosphere.

  The obtained granulated product is sieved with a sieve having an opening of 5.6 mm, and the sieve is further sieved with a sieve of an opening of 2.8 mm to obtain a spherical granulated product having an average particle diameter of 4.4 mm. 12 kg was obtained. The above operation was performed 3 times to obtain 30 kg of spherical granules.

  When 20 hardnesses of the granulated product were measured by the same hardness measurement method as in Example 1 and the average value was obtained, the average hardness of particles having a particle size of 2.0 mm or more was 56N.

  The test was performed in the same manner as in Example 1 except that the filler was changed to 30 kg of spherical granulated material having a particle size of 2.0 mm or more.

When the gas flowing out from the upper part of the filling container was analyzed, BCl ₃ was not detected and the Cl ₂ concentration was 0.1 volume ppm or less.

After 359 hours from the start of the treatment, the Cl ₂ concentration in the effluent gas began to rise exceeding 0.1 ppm by volume. When the filler was taken out, the granulated particles were not pulverized and no odor was generated. Moreover, when this filler was dissolved in water, it was completely dissolved, and no solid waste was generated.

Claims (5)

  A powder of hydrogen carbonate having an average primary particle diameter of 10 to 500 μm is granulated, and the resulting granulated product containing 70 mass% or more of hydrogen carbonate (excluding sodium hydrogen carbonate) is heated to 50 ° C. or higher. In addition, a halogen-based gas removing method of removing a halogen-based gas by bringing it into contact with a halogen-based gas comprising a halogen alone or a halogen compound at less than 80 ° C. The method for removing a halogen-based gas according to claim 1, wherein the granulated product has an average particle diameter of 0.5 to 20 mm and has an average hardness defined below.
In the case of a granulated product having an average particle diameter of 0.5 mm or more and less than 1.0 mm, sieving is performed using a sieve having an average aperture of 0.5 mm and a sieve having an aperture of 1.0 mm, The average hardness obtained by collecting 20 particles under 0 mm sieve and measuring the hardness of each particle is 1N or more,
In the case of a granulated product having an average particle diameter of 1.0 mm or more and less than 1.5 mm, sieving is performed using a sieve having an average aperture of 1.0 mm and a sieve having an aperture of 1.5 mm. The average hardness obtained by collecting 20 particles under 5 mm sieve and measuring the hardness of each particle is 4N or more,
In the case of a granulated product having an average particle diameter of 1.5 mm or more and less than 2.0 mm, sieving is performed using a sieve having an average opening of 1.5 mm and a sieve having an opening of 2.0 mm. The average hardness obtained by collecting 20 particles under 0 mm sieve and measuring the hardness of each particle is 10 N or more,
In the case of a granulated product having an average particle size of 2.0 mm or more and 20 mm or less, a sieve having an average mesh size of 2.0 mm and a sieve having a mesh size of 20 mm is used for sieving. The average hardness obtained by collecting 20 particles and measuring the hardness of each particle is 30 N or more.   The method for removing a halogen-based gas according to claim 1 or 2, wherein the hydrogen carbonate is potassium hydrogen carbonate. The halogen-based gas is selected from the group consisting of BCl ₃ , CCl ₄ , Cl ₂ , SiCl ₄ , HCl, COCl ₂ , F ₂ , SiF ₄ , HF, COF ₂ , NF ₃ , WF ₆ , ClF ₃ and HBr. The method for removing a halogen-based gas according to any one of claims 1 to 3, wherein the halogen-based gas temperature is 50 ° C or higher and lower than 80 ° C.   The method for removing a halogen-based gas according to any one of claims 1 to 4, wherein the granulated product is filled in a container together with activated carbon and brought into contact with the halogen-based gas to remove the halogen-based gas.