JP2004230270A - Method for treating gas using precoated spherical silica gel as adsorbent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating gas by which organic compounds can be efficiently removed from a gas to be treated containing the organic compounds such as ethanol and water, which prevents an adsorbent from being crushed and by which the stable operation can be realized. <P>SOLUTION: The organic compounds in the gas to be treated 1 are adsorbed into the adsorbent 11 by bringing the gas to be treated 1 containing the organic compounds such as ethanol into contact with the adsorbent 11. Then the adsorbent 11 is desorbed and regenerated by heating the organic compounds adsorbed in the adsorbent 11 and the gas to be treated 1 is continuously treated while the regenerated adsorbent 11 is moved in such a way as to be in contact with the gas to be treated 1. At this time, a precoated spherical silica gel is used as the adsorbent 11 which is pretreated with the organic compounds such as ethanol. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas treatment method for removing an organic compound from a gas to be treated containing an organic compound discharged from a factory or the like, and more specifically, uses a so-called pre-coated spherical silica gel obtained by pre-treating a spherical silica gel with an organic compound as an adsorbent. It relates to a gas treatment method.
[0002]
[Prior art]
As a device for removing and recovering organic solvents from exhaust gas containing organic solvents discharged from factories, etc., a fluidized bed type equipped with an adsorption tower, a desorption tower and a recovery unit, and using spherical activated carbon, spherical silica gel, etc. as an adsorbent Gas treatment devices are known (for example, see Patent Documents 1 to 3).
[0003]
In this conventional apparatus, first, an exhaust gas containing an organic solvent is introduced into an adsorption tower and brought into countercurrent contact with a flowing adsorbent. Thereby, the organic solvent in the exhaust gas is adsorbed by the adsorbent and removed. The exhaust gas from which the organic solvent has been removed is discharged from the adsorption tower. On the other hand, the adsorbent that has adsorbed the organic solvent is transferred from the adsorption tower to the desorption tower. In the desorption tower, the organic solvent adsorbed by the desorption gas is desorbed, and the regenerated adsorbent is returned to the adsorption tower for reuse. The desorbed organic solvent is recovered by a recovery device.
[0004]
[Patent Document 1]
Japanese Patent Publication No. 53-8664 [Patent Document 2]
JP-A-54-145374 [Patent Document 3]
JP-B-63-40772 [0005]
[Problems to be solved by the invention]
By the way, when an attempt is made to apply a fluidized bed gas treatment apparatus using silica gel as an adsorbent to exhaust gas containing an organic compound, moisture contained in the exhaust gas is also adsorbed on the silica gel at the same time, and the adsorption capacity for the organic compound is reduced. There is a problem of lowering. In addition, silica gel particles may be crushed by the adsorption of moisture. In this case, the fluidity of the adsorbent decreases, and stable operation of the apparatus becomes difficult, and the treatment efficiency decreases. In addition, there is a problem in that fine particles and dust are generated by crushing the silica gel particles, and the fine particles and the like are discharged out of the apparatus together with the gas.
[0006]
Therefore, the present invention has been made in view of such circumstances, and when silica gel is used as an adsorbent to remove an organic compound from a gas to be treated containing the organic compound and moisture, the organic compound is efficiently removed. It is an object of the present invention to provide a gas treatment method which can perform crushing of an adsorbent and can operate stably.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, a gas treatment method according to the present invention comprises contacting a gas to be treated containing an organic compound with the adsorbent while moving the adsorbent to adsorb the organic compound in the gas to be treated to the adsorbent. In this method, the organic compound adsorbed on the adsorbent is desorbed by heating to regenerate the adsorbent, and the regenerated adsorbent is moved and brought into contact with the gas to be treated again, thereby continuously treating the gas to be treated. In addition, a precoated spherical silica gel obtained by pretreating a spherical silica gel with an organic compound is used as an adsorbent.
[0008]
In the present invention, “the adsorbent is spherical” does not necessarily mean a true spherical shape, and the adsorbent particles are placed on a steel sheet having a smooth surface so as not to overlap, and It means that 90% or more by mass of the adsorbent rolls off the steel plate when tilted.
[0009]
In such a gas treatment method, the organic compound in the gas to be treated is effectively adsorbed and removed by the gas to be treated coming into contact with the adsorbent. The present inventors have found that the use of pre-coated spherical silica gel obtained by pre-treating spherical silica gel with an organic compound as this adsorbent can suppress the adverse effect of adsorption of moisture contained in the gas to be treated, thereby crushing the silica gel and finely pulverizing it. Has been found to be able to sufficiently prevent the generation of methane, and to greatly improve the ability to adsorb organic compounds in the gas to be treated.
[0010]
Here, the pre-treatment of the spherical silica gel with an organic compound (hereinafter sometimes referred to as “pre-coat”) is a treatment of removing the water adsorbed on the spherical silica gel and then adsorbing the organic compound. It can be performed as follows.
[0011]
<Precoat example 1>
The spherical silica gel is filled in a vacuum vessel and kept at a temperature of 100 to 200 ° C. under a reduced pressure of 7000 Pa or less, preferably 0.1 to 2000 Pa for 0.5 to 5 hours to remove moisture adsorbed on the spherical silica gel. . Next, the spherical silica gel is cooled to 40 ° C. or lower, preferably 20 to 40 ° C. while maintaining the reduced pressure. After cooling, an organic compound for pretreatment is introduced into a vacuum vessel, and the organic compound is adsorbed on spherical silica gel to obtain a precoated spherical silica gel.
[0012]
<Precoat example 2>
The spherical silica gel is filled in a pretreatment device, and at a temperature of 100 to 200 ° C., a dry gas having an absolute humidity of 0.1 g (water) / kg (gas) or less is passed to remove moisture adsorbed on the spherical silica gel. As the drying gas, air, nitrogen gas or the like can be used, and among them, air is more preferable. The flow rate of the drying gas is preferably set to 10 to 100 m ³ / h per kg of the spherical silica gel. The time required for removing water is 0.5 hour or more, preferably 0.5 to 5 hours. Next, the spherical silica gel is cooled to 40 ° C. or lower, preferably 20 to 40 ° C. while flowing a dry gas. After cooling, a pretreatment gas consisting of a dry gas containing an organic compound for pretreatment is passed instead of the above-mentioned dry gas, whereby the organic compound is adsorbed on the spherical silica gel to obtain a precoated spherical silica gel.
[0013]
In both cases of Precoat Examples 1 and 2, examples of the pretreatment organic compound used for the precoat include methanol, ethanol, n-propanol, isopropanol, benzene, toluene, acetone, methyl ethyl ketone, and cyclohexane. Among these, preferred are organic compounds that are the same as the organic compounds that are the main objects of removal (main objects adsorbed and removed by the precoated spherical silica gel) contained in the gas to be treated, but are not limited thereto. is not.
[0014]
Further, it is preferable to perform pre-coating using spherical silica gel having a specific surface area of 200 to 900 m ² / g before pre-coating. By setting the specific surface area of the spherical silica gel before the precoating to a value within such a range, sufficient water resistance can be imparted while suppressing the decrease in the amount of the precoated spherical silica gel obtained for the organic compound.
[0015]
Further, a mixture of precoated spherical silica gel and spherical activated carbon may be used as the adsorbent. By using such a mixed adsorbent, organic compounds can be more efficiently removed from the gas to be treated.
[0016]
More specifically, in the present invention, it is desirable to continuously process the gas to be treated while the adsorbent moves by the fluidized bed. In this case, it is useful to use an adsorbent having a particle diameter of 0.4 to 1.4 mm. In the present invention, the expression that the particle diameter of the adsorbent is "lower limit to upper limit" means that when the adsorbent is sieved with a sieve having openings corresponding to the lower limit and the upper limit, the upper limit is used. Means that 90% or more of the mass of what passes through the sieve having an opening corresponding to and remains on the sieve having the opening corresponding to the lower limit value is 90% or more of the total mass.
[0017]
The use of an adsorbent having a particle diameter in such a preferable range makes it easy to maintain the flow rate of the gas to be processed in countercurrent contact with the adsorbent in a suitable range, and the component to be removed in the gas to be processed becomes While sufficiently absorbing and removing a certain organic compound, it is possible to suppress a decrease in treatment capacity.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail. The positional relationship such as up, down, left, and right is based on the positional relationship shown in the drawings unless otherwise specified. The dimensional ratios in the drawings are not limited to the illustrated ratios.
[0019]
The gas treatment method according to the present invention treats a gas to be treated containing an organic compound. Examples of such organic compounds include methanol, ethanol, n-propanol, isopropanol, ethyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, benzene, toluene, xylene, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, and ethyl. Organic compounds such as cellosolve acetate, butyl cellosolve acetate, n-heptane, n-hexane, cyclohexane and the like can be mentioned.
[0020]
Further, the spherical silica gel provided for pre-coating to obtain the pre-coated spherical silica gel as the adsorbent used in the present invention is not particularly limited in physical properties and the like except that the shape is spherical, but the specific surface area is 200 to preferably 900m is ² / g, more preferably a 300~800m ² / g. When the specific surface area is less than 200 m ² / g, the adsorbed amount of the obtained precoated spherical silica gel to the organic compound is disadvantageously reduced. On the other hand, when the specific surface area exceeds 900 m ² / g, the water resistance of the precoated spherical silica gel is increased. Is remarkable.
[0021]
Such spherical silica gel is industrially manufactured as a spherical grade of A-type or B-type silica gel and is generally commercially available. Further, pre-coated spherical silica gel can be obtained in the same manner from water-resistant spherical silica gel produced by further baking these A-type or B-type spherical silica gels at 500 to 1000 ° C.
[0022]
Further, when the gas to be treated contains an organic compound such as methanol and ethyl acetate which is relatively easily adsorbed on the pre-coated spherical silica gel, and n-hexane, an organic compound such as toluene which is relatively hard to be adsorbed on the pre-coated spherical silica gel, these compounds may be used. In order to remove both organic compounds simultaneously, it is preferable to use a mixture of pre-coated spherical silica gel and spherical activated carbon as an adsorbent, that is, to use a mixed adsorbent of pre-coated spherical silica gel and spherical activated carbon. In this case, the mixing ratio between the precoated spherical silica gel and the spherical activated carbon can be appropriately determined in consideration of the type of the component to be removed, the allowable residual component amount in the treated gas, and the like. The spherical activated carbon used here may be, for example, spherical activated carbon obtained by granulating a petroleum-based pitch into a sphere and then activating with water vapor. However, the present invention is not limited to this.
[0023]
Further, as a gas treatment apparatus for effectively carrying out the gas treatment method according to the present invention, since the adsorbent is spherical and has excellent fluidity, the adsorbent is moved while moving the adsorbent of a fluidized bed type, a moving bed type or the like. A gas processing device that is brought into contact with the processing gas can be employed. For example, a fluidized bed continuous gas processing device shown in FIG. 1 is suitable.
[0024]
In FIG. 1, a gas processing apparatus 100 is a continuous gas processing apparatus of a multistage fluidized bed type, and includes an adsorption tower 10, a desorption tower 20, and a recovery unit 30. The adsorption tower 10 has a plurality of trays 12 each formed of a perforated plate inside, and the gas to be treated 1 containing a component to be removed containing an organic compound is supplied from below. The gas 1 to be treated comes into countercurrent contact with the adsorbent 11 (precoated spherical silica gel described above or a mixture of this and spherical activated carbon) which moves to the lower tray in order while forming a fluidized bed on the tray 12. At this time, the components to be removed in the gas to be treated 1 are adsorbed by the adsorbent 11 and removed. The treated gas 2 from which the components to be removed have been removed is discharged from the upper part of the adsorption tower 10. On the other hand, the adsorbent 11 that has adsorbed the component W to be removed is extracted from the lower part of the adsorption tower 10 and supplied to the upper part of the desorption tower 20.
[0025]
The desorption tower 20 includes, for example, a heating unit 21 including a heating unit using a steam, an electric heater, or the like as a heat source, and a cooling unit disposed below the heating unit 21 and including a cooling unit using, for example, water or the like as a refrigerant. It has a part 22. The carrier gas G is introduced into the lower part of the desorption tower 20, and the carrier gas G sent out from the upper part of the heating unit 21 is introduced into the recovery unit 30.
[0026]
The adsorbent 11 adsorbing the component W to be removed supplied from the upper part of the desorption tower 20 moves downward by gravity and is heated to, for example, 100 to 250 ° C. in the heating unit 21 to desorb the component W to be removed. I do. The component W removed from the adsorbent 11 is carried by the carrier gas G to the recovery unit 30 and separated from the carrier gas G by a method such as cooling by the cooling device 40 and then sent to the recovery system 50 to be recovered. Is done.
[0027]
On the other hand, the adsorbent 11 from which the component W to be removed is desorbed and regenerated in the heating unit 21 is cooled to, for example, 20 to 60 ° C. in the cooling unit 22, and then extracted from the lower part of the desorption tower 20, and is again adsorbed. 10 to the top. In this way, the adsorbent 11 circulates and moves between the adsorption tower 10 and the desorption tower 20, and repeats the adsorption and desorption of the component to be removed in the gas to be treated 1, whereby the gas to be treated 1 is continuously processed.
[0028]
Here, when a fluidized bed type device such as the gas treatment device 100 is used, the particle diameter of the adsorbent 11 is preferably 0.4 to 1.4 mm, more preferably 0.5 to 1.4 mm. 1.2 mm. When the particle size of the adsorbent 11 is less than 0.4 mm, the flow rate of the gas 1 to be treated must be excessively small in order to prevent the particles of the adsorbent 11 from being scattered in the adsorption tower 10. Causes a decline.
[0029]
On the other hand, when the particle size of the adsorbent 11 exceeds 1.4 mm, it is necessary to excessively increase the flow rate of the gas 1 to be treated for forming a fluidized bed in the adsorption tower 10. The contact time between the gas 1 and the adsorbent 11 becomes undesirably short. To avoid this and secure a sufficient contact time, it is necessary to take measures such as increasing the number of fluidized beds and increasing the height of the fluidized bed.
[0030]
【Example】
Hereinafter, specific examples according to the present invention will be described, but the present invention is not limited thereto.
[0031]
<Measurement of specific surface area of spherical silica gel>
It was measured by the t-plot method of JIS K1150.
[0032]
In the following Examples and Comparative Examples, the gas flow rate is a value converted into a standard state, and ppm is based on volume.
[0033]
<Example 1>
Air containing 1000 ± 100 ppm of methanol as a component to be removed and having a temperature of 30 ° C. and a relative humidity of 40% was continuously supplied at a flow rate of 60 m ³ / h to the gas treatment apparatus 100 having the configuration shown in FIG. Further, the adsorption tower 10 had a multistage fluidized bed configuration having an inner diameter of 155 mm and six perforated plate trays 12. Here, as the adsorbent 11, a pre-coated spherical particle obtained by pre-coating A-type spherical silica gel (Fuji Silica Chemical Ltd .; Fuji Silica A type) having a specific surface area of 650 m ² / g and a particle diameter of 0.71 to 1.18 mm with methanol is used. The circulation amount was 2 kg / h using silica gel.
[0034]
On the other hand, the desorption tower 20 had an inner diameter of 155 mm, and the heating unit 21 used an electric heater as an indirect heating source. At this time, the desorption temperature was 150 ° C., and nitrogen gas as the carrier gas G was circulated at 0.4 m ³ / h. In the cooling unit 22, the adsorbent 11 was cooled to 40 ° C. Further, chiller water at 5 ° C. was circulated as a refrigerant in the recovery unit 30 to cool and liquefy the desorbed component W to be removed.
[0035]
As a result, the methanol concentration in the treated gas 2 (treated air) at the outlet of the adsorption tower 10 was about 10 ppm. At this time, in the recovery unit 30, methanol was recovered at 0.08 kg / h, and water was recovered at 0.24 kg / h. Moreover, the gas processing apparatus 100 was able to operate stably for 40 consecutive days, and the methanol removal rate was maintained at a sufficiently high value of about 99%.
[0036]
The pre-coating of spherical silica gel with methanol was performed as follows. First, spherical silica gel was filled in a vacuum vessel and kept at a temperature of 180 ° C. under a reduced pressure of about 130 Pa for 1 hour to remove water adsorbed on the spherical silica gel. Next, the spherical silica gel was cooled to 30 ° C. while maintaining the reduced pressure. After cooling, dry nitrogen containing 1000 ppm of methanol was introduced into a vacuum vessel to return to normal pressure, and the state was maintained for 1 hour, whereby methanol was adsorbed on the spherical silica gel to obtain a precoated spherical silica gel.
[0037]
<Example 2>
As the adsorbent 11, a pre-coated spherical silica gel obtained by pre-coating B-type spherical silica gel (manufactured by Fuji Silysia Chemical Ltd .; Fuji Silica Gel B type) having a specific surface area of 450 m ² / g and a particle diameter of 0.71 to 1.18 mm with methanol was used. Except for this, the exhaust gas treatment was performed in the same manner as in Example 1. The pre-coating of spherical silica gel with methanol was performed in the same manner as in Example 1. As a result, the methanol concentration in the treated gas 2 (treated air) at the outlet of the adsorption tower 10 was about 20 ppm. At this time, in the recovery unit 30, methanol was recovered at 0.08 kg / h, and water was recovered at 0.30 kg / h. Further, the gas treatment apparatus 100 was able to operate stably for 40 consecutive days, and the methanol removal rate was maintained at a sufficiently high value of about 98%.
[0038]
<Example 3>
As the adsorbent 11, a pre-coated spherical silica gel obtained by pre-coating a water-resistant spherical silica gel having a specific surface area of 550 m ² / g and a particle diameter of 0.71 to 1.18 mm (manufactured by Fuji Silysia Chemical Ltd .; CARiACT Q-3) with methanol was used. Except for this, the exhaust gas treatment was performed in the same manner as in Example 1. The pre-coating of water-resistant spherical silica gel with methanol was performed in the same manner as in Example 1. As a result, the methanol concentration in the treated gas 2 (treated air) at the outlet of the adsorption tower 10 was about 10 ppm. At this time, in the recovery unit 30, methanol was recovered at 0.08 kg / h, and water was recovered at 0.24 kg / h. Moreover, the gas processing apparatus 100 was able to operate stably for 40 consecutive days, and the methanol removal rate was maintained at a sufficiently high value of about 99%.
[0039]
<Example 4>
Air having a temperature of 30 ° C. and a relative humidity of 40% containing 1000 ± 100 ppm of methanol and 1000 ± 100 ppm of toluene as components to be removed was supplied to the same fluidized-bed type gas treatment apparatus 100 used in Example 1 at a flow rate of 60 m ^3. / H. Further, as the adsorbent 11, a pre-coated spherical silica gel obtained by pre-coating the A-type spherical silica gel used in Example 1 with methanol in the same manner as in Example 1 and a petroleum pitch-based spherical activated carbon having a particle diameter of 0.6 to 1.00 mm (G-BAC manufactured by Kureha Chemical Industry Co., Ltd.) was mixed at a mass ratio of 50:50, and the circulation amount was 4 kg / h. Further, the desorption temperature was set to 150 ° C., a nitrogen gas as the carrier gas G was circulated at 0.8 m ³ / h, and the adsorbent was cooled to 40 ° C. in the cooling unit 22.
[0040]
As a result, the methanol concentration in the treated gas 2 (treated air) at the outlet of the adsorption tower 10 was about 50 ppm, and the toluene concentration was about 2 ppm. At this time, 0.08 kg / h of methanol, 0.25 kg / h of toluene, and 0.24 kg / h of water were recovered in the recovery unit 30. In addition, the gas processing apparatus 100 was able to operate stably for 40 consecutive days, and maintained sufficiently high values of the methanol removal rate of about 95% and the toluene removal rate of about 99.8%. As described above, by using the mixed adsorbent, both the organic compound relatively easily adsorbed on the spherical silica gel and the organic compound relatively hardly adsorbed from the gas to be treated containing both of these organic compounds with a high removal rate. It was confirmed that it could be removed stably.
[0041]
<Comparative Example 1>
Exhaust gas treatment was carried out in the same manner as in Example 1, except that A-type spherical silica gel (Fuji Silysia Chemical Ltd .; Fuji Silica A type) before pre-coating with methanol was used as the adsorbent. As a result, the methanol concentration in the treated gas 2 (treated air) at the outlet of the adsorption tower 10 was about 100 ppm. However, when the gas treatment apparatus 100 is continuously operated for about 7 days, the flow state of the fluidized bed of the adsorption tower 10 becomes unstable due to the crushing of the spherical silica gel as the adsorbent, and the quantitative circulation of the adsorbent becomes impossible. Therefore, the operation of the gas processing device was stopped.
[0042]
<Comparative Example 2>
Exhaust gas treatment was carried out in the same manner as in Example 2 except that B-type spherical silica gel (Fuji Silysia Chemical Ltd .; Fuji Silica Gel B type) before pre-coating with methanol was used as the adsorbent. As a result, the methanol concentration in the treated gas 2 (treated air) at the outlet of the adsorption tower 10 was about 200 ppm. However, when the gas treatment device 100 is continuously operated for about 20 days, the flow state of the fluidized bed of the adsorption tower 10 becomes unstable due to the crushing of the spherical silica gel as the adsorbent, and the quantitative circulation of the adsorbent becomes impossible. Therefore, the operation of the gas processing device was stopped.
[0043]
<Comparative Example 3>
Except that a water-resistant spherical silica gel (Fuji Silysia Chemical Ltd .; CARiACT Q-3) having a specific surface area of 550 m ² / g and a particle diameter of 0.71 to 1.18 mm, which was not precoated with methanol, was used as an adsorbent. Exhaust gas treatment was performed in the same manner as in Example 3.
[0044]
As a result, the methanol concentration in the treated gas 2 (treated air) at the outlet of the adsorption tower 10 was about 100 ppm. At this time, in the recovery unit 30, methanol was recovered at 0.08 kg / h, and water was recovered at 0.50 kg / h. Moreover, the gas processing apparatus 100 was able to operate stably for 40 consecutive days. However, the removal rate of methanol was about 90%, and when water-resistant spherical silica gel pre-coated with methanol (manufactured by Fuji Silysia Chemical Ltd .; CARiACT Q-3) was used as the adsorbent 11 (Example 3: methanol removal rate 99). %) Was found to have a lower methanol removal rate.
[0045]
<Comparative Example 4>
A-type spherical silica gel not pre-coated with methanol (manufactured by Fuji Silysia Chemical Ltd .; Fuji Silica A type) as an adsorbent and petroleum pitch-based spherical activated carbon having a particle diameter of 0.6 to 1.00 mm (manufactured by Kureha Chemical Industry Co., Ltd.) G-BAC), except that exhaust gas treatment was performed in the same manner as in Example 4. As a result, the methanol concentration in the treated gas 2 (treated air) at the outlet of the adsorption tower 10 was about 200 ppm, and the toluene concentration was about 2 ppm. However, when the gas treatment apparatus 100 is continuously operated for about 14 days, the flow state of the fluidized bed of the adsorption tower 10 becomes unstable due to the crushing of the spherical silica gel as the adsorbent, and the quantitative circulation of the adsorbent becomes impossible. Therefore, the operation of the gas processing device was stopped.
[0046]
【The invention's effect】
As described above, according to the gas treatment method of the present invention, a pre-coated spherical silica gel pretreated with a spherical silica gel with an organic compound is used as an adsorbent, and a gas to be treated containing an organic compound is subjected to a fluidized bed gas treatment apparatus. Treatment using a gas treatment device that moves and adsorbs the adsorbent, such as a moving bed type gas treatment device or the like, can sufficiently suppress crushing of the adsorbent due to adsorption of moisture in the gas to be treated. Organic compounds contained in the processing gas can be continuously removed at a high removal rate for a long time.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an example of a fluidized-bed gas processing apparatus suitable for carrying out the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Gas to be processed, 2 ... Treated gas, 10 ... Adsorption tower, 11 ... Adsorbent, 12 ... Tray, 20 ... Desorption tower, 21 ... Heating unit, 22 ... Cooling unit, 30 ... Recovery unit, 100 ... Gas treatment apparatus.

Claims (6)

The gas to be treated containing an organic compound is brought into contact with the adsorbent while moving the adsorbent to adsorb the organic compound in the gas to be treated to the adsorbent, and the organic compound adsorbed by the adsorbent is removed. A gas processing method of desorbing by heating to regenerate the adsorbent, bringing the regenerated adsorbent into contact with the gas to be treated again while moving, and continuously treating the gas to be treated,
A gas treatment method using a precoated spherical silica gel obtained by pretreating a spherical silica gel with an organic compound as the adsorbent. The gas treatment method according to claim 1, wherein the organic compound used in the pretreatment is the same as the organic compound as a main removal target contained in the gas to be treated. The gas treatment method according to claim 1, wherein the spherical silica gel has a specific surface area of 200 to 900 m ² / g. The gas treatment method according to any one of claims 1 to 3, wherein a substance further containing spherical activated carbon is used as the adsorbent. The gas treatment method according to any one of claims 1 to 4, wherein the gas to be treated is continuously treated while the adsorbent moves by a fluidized bed. The gas processing method according to claim 5, wherein the adsorbent has a particle diameter of 0.4 to 1.4 mm.

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