JP5527447B2 - Organic solvent dehydrator - Google Patents

Description

  The present invention relates to an apparatus for dehydrating water from an organic solvent, and more particularly to an organic solvent dehydrating apparatus used for dehydrating an organic solvent recovered from an organic solvent-containing gas generated from various factories or research facilities using a solvent recovery apparatus. .

  Conventionally, a distillation purification apparatus has been widely used as an apparatus for removing water from an organic solvent to dehydrate the solvent. That is, it is an apparatus that can obtain a high-purity organic solvent by heating and evaporating the solvent and fractionating the organic solvent and moisture using the difference in boiling point.

  Since the distillation purification apparatus is a large apparatus, a large installation space is required, and both initial cost and running cost are high. In order to solve such a problem, a method of removing water by passing an organic solvent through a dehydration tank filled with a dehydrating material such as zeolite, ion exchange resin, molecular sieves, and activated alumina is known (for example, patents). Reference 1).

  However, when separating water from a large amount of organic solvent, a large amount of dehydrating material is required, and when the dehydrating material is broken, it is necessary to replace the dehydrating material. Increase. Therefore, although it is an effective means at the laboratory level, it is not satisfactory for separating water from a large amount of organic solvent recovered from factories or research facilities.

  Therefore, in Patent Document 2 below, a dehydration step of adsorbing moisture contained in an organic solvent to the dehydrating material by passing the organic solvent through the dehydrating material packed in a dehydrating tank (adsorption tower). And an organic solvent dehydration apparatus using a cation exchange resin as a dehydrating material, and a drying step of drying moisture adsorbed on the dehydrating material by passing an inert gas or air through the dehydrating material. Yes.

JP 2000-225316 A JP 2009-291676 A

  However, when an ion exchange resin or the like is used as the dehydrating material, if the drying speed is increased when the dehydrating material is dried after the dehydrating step, the dehydrating material is destroyed due to the difference in water content between the inner and outer layers of the dehydrating material. As a result, clogging occurs in the filter provided in the dewatering tank due to debris of the dehydrating material, which may reduce the dewatering ability of the organic solvent dewatering apparatus.

  An object of the present invention is to provide an organic solvent dehydrating apparatus having a configuration that does not reduce the dehydrating ability of the organic solvent dehydrating apparatus.

  In the organic solvent dehydrating apparatus based on this invention, the organic solvent dehydrating apparatus for dehydrating and removing the water contained in the organic solvent to be treated by introducing the organic solvent to be treated containing water into the dehydrating material and bringing it into contact with the dehydrating material. The dehydrating material includes a cation exchange resin having a spherical shape, and the dehydrating material has a particle ratio of 90% or more when the particle size of the cation exchange resin is 0.4 mm or less.

  In another embodiment, the matrix structure of the cation exchange resin is at least one selected from the group consisting of an acrylic acid polymer, a methacrylic acid polymer, and a styrene-divinylbenzene copolymer, Carboxylic acid Ca group or sulfonic acid Na group is provided.

  In another embodiment, a dehydrating tank filled with the dehydrating material, an organic solvent introduction path for introducing the organic solvent to be treated into the dehydrating tank, and an inert gas for introducing an inert gas into the dehydrating tank An introduction path and a dry air introduction path for introducing air for drying into the dewatering tank.

  In another form, it further includes a washing water introduction path for introducing washing water into the dehydration tank and a washing water discharge path for discharging the washing water from the dehydration tank.

  In another embodiment, the washing water introduction path has a washing water circulation path for introducing the washing water discharged to the washing water discharge path into the washing water introduction path.

  In another embodiment, the dehydration tank includes a first dehydration tank and a second dehydration tank, and when the drying air is introduced into the first dehydration tank through the dry air introduction path, When the organic solvent to be treated is introduced into the second dehydration tank through the organic solvent introduction path, and the drying air is introduced into the second dehydration tank through the dry air introduction path, the organic solvent introduction path to be treated is introduced. By introducing the organic solvent to be treated into the first dewatering tank by the above, the organic solvent to be treated is continuously introduced into the dehydrating material and brought into contact with the dehydrating material, so that the moisture contained in the organic solvent to be treated is reduced. Dehydration removal is possible.

  According to the organic solvent dehydrating apparatus based on the present invention, it is possible to provide an organic solvent dehydrating apparatus having a configuration that does not reduce the dehydrating ability.

It is a figure which shows the organic-solvent dehydration apparatus of the dehydration tank in embodiment one-column type. The dehydration tank in other embodiment is a figure which shows the organic solvent dehydration apparatus of a two tower type system. It is a figure which shows the organic-solvent collection | recovery processing apparatus using the activated carbon fiber in other embodiment. It is a figure which shows various conditions of the dehydrating material used for Example 1 to Example 3 and Comparative Example 1 to Comparative Example 3.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the same or corresponding parts are denoted by the same reference numerals in the drawings, and the description thereof may not be repeated. In the embodiments described below, when referring to the number, amount, and the like, the scope of the present invention is not necessarily limited to the number, amount, and the like unless otherwise specified.

  An organic solvent dehydrating apparatus based on the present invention includes a dehydration process facility for allowing an organic solvent containing water to flow through a dehydrating material filled in a dehydrating tank and adsorbing moisture to the dehydrating material, and drying air to the dehydrating material. It is preferable that the organic solvent dehydrator is provided with a drying process facility for passing the water adsorbed on the dehydrating material through the flow and alternately performing the process. This is because the processing can be continuously performed by adopting such a structure.

  A more preferable device structure is an organic solvent dehydrating device in which the dehydrating material is divided into several parts, and the dehydrating step and the drying step are switched by a damper or the like, and dehydration and drying are continuously performed. In addition, the organic solvent dehydrating apparatus has a structure in which the dehydrating material can rotate and the portion of the dehydrating material that has adsorbed moisture in the dehydrating process moves to the drying process by the rotation of the dehydrating material.

  Hereinafter, an organic solvent dehydrating apparatus according to the present invention will be described in detail with reference to the drawings. FIG. 1 is an example of a preferred embodiment of the present invention. In the organic solvent dehydrating apparatus illustrated in FIG. 1, when the dampers 4 and 5 are opened, the organic solvent containing moisture is dehydrated from the stored organic solvent tank 2 through the organic solvent introduction line 3 to be processed. Is sent to the dehydration tank 1 filled with, and the refined organic solvent is sent to the refined organic solvent tank 7 through the refined organic solvent discharge line 6, so that moisture is adsorbed and removed by the dehydrating material to adsorb the organic solvent. Process.

  On the other hand, when the dampers 4 and 5 are closed and the dampers 24 and 25 are open, if the damper 13 is open, the water pump 12 is used to supply water to the dehydration tank 1 through the water or dry air introduction line 23. It is preferable to have a water purge step of removing the organic solvent adhering and remaining on the surface of the dehydrating material by flowing water. This may be performed by using an inert gas such as nitrogen without performing the water purging step, but may be performed by a drying step which will be described later, but by purging and removing the organic solvent with water, This is because it is not necessary to use an inert gas which is expensive.

  In the water purging step, the purge water discharged from the water or dry air discharge line 26 contains an organic solvent and may be accumulated and incinerated. However, the damper 27 is opened and the return line 28 is covered. It is preferable to return to the treated organic solvent tank 2. This is because the number of steps can be omitted and this method is efficient.

  Further, in a step after the water purge step, the damper 13 is closed and the damper 22 is opened, and the dry air is sent to the dehydration tank 1 through the water or dry air introduction line 23. It is preferable to have a drying step for drying the adsorbed moisture. The gas generated by the drying process contains a small amount of organic solvent, and the gas discharged from the water or dry air discharge line 26 is directly converted into a combustion device such as a direct combustion device, a catalytic combustion device, a regenerative combustion device, or activated carbon. It can process with the gas processing apparatus generally used, such as the solvent collection | recovery apparatus which uses a fiber.

  In the drying step, when the temperature of the dry air is 5 to 30 ° C., the dew point of the dry air is preferably negative. This is because the lower the dew point and the dry air, the shorter the drying time for drying the moisture from the dehydrating material. In order to lower the dew point, it is preferable to use the compressor 21. It is more preferable to further lower the dew point of the drying air by installing an air dryer or the like downstream of the compressor 21. Alternatively, it is more preferable to heat the drying air to 40 to 80 ° C. by installing a heater or the like downstream of the compressor 21. Furthermore, it is more preferable to use heated air having a low dew point as a dry gas by combining an air dryer or the like with a heater or the like.

  By continuously repeating the above dehydration step → water purge step → drying step, the apparatus can effectively and economically dehydrate and remove moisture from the organic solvent containing moisture. By such continuous dehydration-air drying, moisture in the organic solvent can be removed stably at a low cost and with a high capacity.

  The dehydrating material in the present embodiment includes a cation exchange resin having a spherical shape, and the dehydrating material preferably has a particle ratio of 90% or more when the particle size of the cation exchange resin is 0.4 mm or less. The spherical shape here does not mean only a geometrical spherical shape, but may be an ellipsoid, but a shape close to a true spherical shape is more preferable. In the case of an ellipsoid, it is preferable that the ratio of the longest diameter (major axis diameter) to the shortest diameter (minor axis diameter) of three diameters orthogonal to each other is preferably 2 or less, and 1.3 or less. Further preferred. The particle ratio is defined as particles having a specific particle size contained in 100% of all cation exchange resins (cation exchange resin filled in the dehydration tank 1) constituting the dehydrating material. The ratio of the number that exists.

  The matrix structure of the cation exchange resin is at least one selected from the group consisting of acrylic acid-based polymers, methacrylic acid-based polymers, and styrene-divinylbenzene copolymers. The matrix structure includes a carboxylic acid Ca group or a sulfonic acid. It is preferable that Na group is provided.

  The operation of the dehydrating material according to the present embodiment preferably employs a system capable of continuously removing two or more dewatering tanks as shown in FIG. 2, but the amount of moisture to be removed and the organic solvent to be treated In consideration of the amount of the above, intermittent operation may be performed. This is because, under conditions where the amount of moisture contained or the amount of the organic solvent to be treated is small, it is not required that the operation is continuous, and the operation cost can be reduced.

  The organic solvent that can be dehydrated in the present embodiment is not particularly limited, such as ethyl acetate, methyl acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, methylene chloride, chloroform, and dichloromethane, and can be used in various organic solvents. It is.

  The organic solvent that can be dehydrated in the present embodiment is an organic solvent that is recovered using a solvent recovery processing device, which contains an organic solvent discharged from a factory in various fields, such as a dry laminating process for laminating films. Can also be applied.

  For example, in the organic solvent recovery processing apparatus as shown in FIG. 3, the organic solvent is adsorbed by the activated carbon fiber element 44 in which the gas 41 to be processed is introduced from the fan 42 and filled in the adsorption tower 43, and the clean gas 46 is obtained. The adsorption process discharged into the outside air and the introduction of steam 45 into the activated carbon fiber element 44 desorbs the organic solvent, cools and condenses with the condenser 47, separates the solvent and water with the separator 48, and collects the recovered solvent 49. There is a desorption process, and the system is capable of continuous processing by alternately performing the adsorption process and the desorption process.

  Since this type of solvent recovery processing apparatus uses steam for desorption or cooling and condenses, moisture is mixed into the recovered solvent. Therefore, by applying the organic solvent dehydrating apparatus in the present embodiment, the recovered solvent It is possible to effectively remove moisture from the water.

  In the organic solvent dehydrating apparatus shown in FIG. 1 and FIG. 2, the cleaning water discharged to the cleaning water discharge path or the dry water discharging line 26 is introduced into the cleaning water introduction path water or the dry air introducing line 23. In order to do this, a washing water circulation path 51 that branches from the dry air discharge line 26 to the water tank 11 may be provided. The opening and closing of the line of the washing water circulation path 51 is controlled by a damper 52.

  Hereinafter, the details of the organic solvent dehydrating apparatus in the embodiment based on the present invention will be further described by Examples 1 to 3 and Comparative Examples 1 to 3, but the present invention is not limited to these Examples. . FIG. 4 shows various conditions of the dehydrating material used in Examples 1 to 3 and Comparative Examples 1 to 3.

Example 1
In the organic solvent dehydrating apparatus shown in FIG. 1, a spherical cation exchange resin in which a dehydrating material is modified with a sulfonic acid Na group having a base structure of a styrene-divinylbenzene copolymer having a rack strength of 8% is used and the particle size range is 0 The particle ratio of 0.2 mm to 0.5 mm and a particle size of 0.4 mm or less was 90%. The spherical cation exchange resin was measured using a particle size distribution measuring instrument (HORIBA LA-950V2) based on “Particle Size Analysis Laser Diffraction Method” defined in Japanese Industrial Standard (JIS Z 8825-1). I did it.

  19 kg of this cation exchange resin is filled into the dehydration tank 1 and, as a solvent dehydration process, a mixed liquid of 3% by mass of moisture and 97% by mass of ethyl acetate is introduced into the dehydration tank 1 from the treated organic solvent introduction line 3 at 200 L / hr. did. At this time, the adsorption temperature was 30 ° C.

  Next, as a water washing step, 20 L / min of tap water was introduced into the dehydration tank 1 through the water or dry air introduction line 23 to wash the solvent adhering to the dehydrating material. Next, as a drying step, the air volume was adjusted so that the maximum pressure loss of the dehydrating tank 1 did not exceed 90 kPa, and dry heated air of 100 ° C. and 0 ° C. DP (Dew Point (dew point)) was introduced into the dehydrating tank 1.

This solvent dehydration step → water washing step → drying step required 4.5 hr. When this step was repeated 20 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the solvent dehydration step was 0.9% by mass. The amount of drying air during the drying process at this time was 180 m ³ / hr.

Furthermore, when this step was repeated 200 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the solvent dehydration step was reduced to 0.9% by mass, as in the above 20 cycles, and the drying step at this time The dry air volume at that time was 180 m ³ / hr. In Example 1, the mixed solvent dehydrated by the organic solvent dehydrating apparatus has an average outlet water concentration of 0.9 even if the solvent dehydration process → water washing process → drying process is repeated. It was possible to maintain the mass%, and there was no deterioration in performance, and the dehydration process could be stably performed with high efficiency.

  This is a spherical cation exchange resin in which the dehydrating material is modified with a sulfonic acid Na group whose base structure is a styrene-divinylbenzene copolymer having a rack strength of 8%, and the particle size range is 0.2 to 0.5 mm. Since the particle ratio of the particle size of 0.4 mm or less was 90%, the cation exchange resin was hardly destroyed even in the drying process, and the filter provided in the dewatering tank was clogged with debris from the dehydrating material. This is probably because the dehydration capability of the organic solvent dehydrator was maintained.

(Example 2)
In the organic solvent dehydrating apparatus shown in FIG. 1, a plurality of spherical cation exchange resins modified with Na sulfonate group having a base structure of styrene-divinylbenzene copolymer with a dehydrating strength of 8% are used. The particle ratio of 0.1 mm to 1.0 mm and a particle size of 0.4 mm or less was 90%. The spherical cation exchange resin was measured using a particle size distribution measuring instrument (HORIBA LA-950V2) based on “Particle Size Analysis Laser Diffraction Method” defined in Japanese Industrial Standard (JIS Z 8825-1). I did it.

  19 kg of this cation exchange resin is filled in the dehydration tank 1, and as a solvent dehydration step, an organic solvent to be treated is introduced at a rate of 200 L / hr with a mixed liquid of 3% by mass of water, 80% by mass of ethyl acetate and 17% by mass of n-propyl acetate. It was introduced into the dehydration tank 1 from the line 3. At this time, the adsorption temperature was 30 ° C.

  Next, as a water washing step, 20 L / min of tap water was introduced into the dehydration tank 1 through the water or dry air introduction line 23 to wash the solvent adhering to the dehydrating material. Next, as a drying step, the air volume was adjusted so that the maximum pressure loss of the dehydrating tank 1 did not exceed 90 kPa, and dry heated air of 100 ° C. and 0 ° C. DP (Dew Point (dew point)) was introduced into the dehydrating tank 1.

This solvent dehydration step → water washing step → drying step required 4.5 hr. When this step was repeated 20 times, the average water concentration at the outlet in the mixed solvent dehydrated in the solvent dehydration step was 0.95% by mass. The amount of drying air at the time of the drying step was 160 m ³ / hr.

Further, when this process was repeated 200 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the solvent dehydration process was reduced to 0.95% by mass, as in the above 20 cycles, and the drying process at this time The dry air volume at that time was 160 m ³ / hr. In Example 2, the mixed solvent dehydrated by the organic solvent dehydrating apparatus has an average outlet water concentration of 0.95 even if the solvent dehydration step → water washing step → drying step is repeated. It was possible to maintain the mass%, and there was no deterioration in performance, and the dehydration process could be stably performed with high efficiency.

  This is a spherical cation exchange resin in which the dehydrating material is modified with a sulfonic acid Na group whose base structure is a styrene-divinylbenzene copolymer having a rack strength of 8%, and the particle size range is 0.1 to 1.0 mm. Since the particle ratio of the particle size of 0.4 mm or less was 90%, the cation exchange resin was hardly destroyed even in the drying process, and the filter provided in the dewatering tank was clogged with debris from the dehydrating material. This is probably because the dehydration capability of the organic solvent dehydrator was maintained.

(Example 3)
In the organic solvent dehydrating apparatus shown in FIG. 1, a plurality of spherical cation exchange resins modified with Na sulfonate group having a base structure of styrene-divinylbenzene copolymer with a dehydrating strength of 8% are used. The particle ratio of 0.38 mm to 0.4 mm and a particle size of 0.4 mm or less was 100%. The spherical cation exchange resin was measured using a particle size distribution measuring instrument (HORIBA LA-950V2) based on “Particle Size Analysis Laser Diffraction Method” defined in Japanese Industrial Standard (JIS Z 8825-1). I did it.

  19 kg of this cation exchange resin is filled in the dehydration tank 1, and as a solvent dehydration step, a mixed liquid of 2% by mass of water, 88% by mass of methylene chloride, and 10% by mass of methanol is fed at 200 L / hr from the organic solvent introduction line 3 to be treated. The dehydration tank 1 was introduced. At this time, the adsorption temperature was 30 ° C.

  Next, as a water washing step, 20 L / min of tap water was introduced into the dehydration tank 1 through the water or dry air introduction line 23 to wash the solvent adhering to the dehydrating material. Next, as a drying step, the air volume was adjusted so that the maximum pressure loss of the dehydrating tank 1 did not exceed 90 kPa, and dry heated air of 100 ° C. and 0 ° C. DP (Dew Point (dew point)) was introduced into the dehydrating tank 1.

This solvent dehydration step → water washing step → drying step required 4.5 hr. When this step was repeated 20 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the solvent dehydration step was 0.5 mass%. The amount of drying air at the time of the drying process at this time was 220 m ³ / hr.

Further, when this step was repeated 200 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the solvent dehydration step was reduced to 0.5% by mass, as in the above 20 cycles, and the drying step at this time The dry air volume at that time was 220 m ³ / hr. In Example 3, the mixed solvent dehydrated by the organic solvent dehydrating apparatus had an outlet average water concentration of 0.5% in the dehydrated mixed solvent even when the solvent dehydration step → water washing step → drying step was repeated. It was possible to maintain the mass%, and there was no deterioration in performance, and the dehydration process could be stably performed with high efficiency.

  This is a spherical cation exchange resin in which the dehydrating material is modified with a sulfonic acid Na group having a base structure of a styrene-divinylbenzene copolymer having a rack strength of 8%, and the particle size range is 0.38 to 0.4 mm. Since the particle ratio of the particle size of 0.4 mm or less was 100%, the cation exchange resin was hardly destroyed even in the drying process, and the filter provided in the dehydration tank was clogged with debris from the dehydrating material. This is probably because the dehydration capability of the organic solvent dehydrator was maintained.

(Comparative Example 1)
In the organic solvent dehydrating apparatus shown in FIG. 1, a plurality of spherical cation exchange resins modified with Na sulfonate group having a base structure of styrene-divinylbenzene copolymer with a dehydrating strength of 8% are used. The particle ratio of 0.6 mm to 0.7 mm and a particle size of 0.4 mm or less was 0%. The spherical cation exchange resin was measured using a particle size distribution measuring instrument (HORIBA LA-950V2) based on “Particle Size Analysis Laser Diffraction Method” defined in Japanese Industrial Standard (JIS Z 8825-1). I did it.

  19 kg of this cation exchange resin is filled into the dehydration tank 1 and, as a solvent dehydration process, a mixed liquid of 3% by mass of moisture and 97% by mass of ethyl acetate is introduced into the dehydration tank 1 from the treated organic solvent introduction line 3 at 200 L / hr. did. At this time, the adsorption temperature was 30 ° C.

  Next, as a water washing step, 20 L / min of tap water was introduced into the dehydration tank 1 through the water or dry air introduction line 23 to wash the solvent adhering to the dehydrating material. Next, as a drying step, the air volume was adjusted so that the maximum pressure loss of the dehydrating tank 1 did not exceed 90 kPa, and dry heated air of 100 ° C. and 0 ° C. DP (Dew Point (dew point)) was introduced into the dehydrating tank 1.

This solvent dehydration step → water washing step → drying step required 4.5 hr. When this step was repeated 20 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the solvent dehydration step was 0.9% by mass. The amount of drying air during the drying process at this time was 180 m ³ / hr.

Furthermore, when this process was repeated 200 cycles, the average water concentration at the outlet of the mixed solvent dehydrated in the solvent dehydration process increased to 1.8% by mass, and the amount of drying air at the time of the drying process was 100 m ^3. / Hr. In Comparative Example 1, the mixed solvent dehydrated by the organic solvent dehydrating apparatus is an outlet in the mixed solvent dehydrated in the solvent dehydration process when the solvent dehydration process → water washing process → drying process is repeated. The average moisture concentration increases.

  This is because the dehydrating material used is a plurality of spherical cation exchange resins modified with Na sulfonic acid group based on a styrene-divinylbenzene copolymer with a dehydrating strength of 8%, and the particle size range is 0.6 mm. Since the particle ratio of 0.7 mm and particle size of 0.4 mm or less was 0%, there were many cation exchange resin particles destroyed in the drying process. As a result of the clogging of the obtained filter, it is considered that the dewatering ability of the organic solvent dewatering device was lowered.

(Comparative Example 2)
In the organic solvent dehydrating apparatus shown in FIG. 1, a plurality of spherical cation exchange resins modified with Na sulfonate group having a base structure of styrene-divinylbenzene copolymer with a dehydrating strength of 8% are used. The particle ratio of 0.35 mm to 0.5 mm and a particle size of 0.4 mm or less was 80%. The spherical cation exchange resin was measured using a particle size distribution measuring instrument (HORIBA LA-950V2) based on “Particle Size Analysis Laser Diffraction Method” defined in Japanese Industrial Standard (JIS Z 8825-1). I did it.

  19 kg of this cation exchange resin is filled in the dehydration tank 1, and as a solvent dehydration step, an organic solvent to be treated is introduced at a rate of 200 L / hr with a mixed liquid of 3% by mass of water, 80% by mass of ethyl acetate and 17% by mass of n-propyl acetate. It was introduced into the dehydration tank 1 from the line 3. At this time, the adsorption temperature was 30 ° C.

  Next, as a water washing step, 20 L / min of tap water was introduced into the dehydration tank 1 through the water or dry air introduction line 23 to wash the solvent adhering to the dehydrating material. Next, as a drying step, the air volume was adjusted so that the maximum pressure loss of the dehydrating tank 1 did not exceed 90 kPa, and dry heated air of 100 ° C. and 0 ° C. DP (Dew Point (dew point)) was introduced into the dehydrating tank 1.

This solvent dehydration step → water washing step → drying step required 4.5 hr. When this step was repeated 20 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the solvent dehydration step was 0.85% by mass. The amount of drying air during the drying process was 200 m ³ / hr.

Furthermore, when this process was repeated 200 cycles, the average water concentration at the outlet of the mixed solvent dehydrated in the solvent dehydration process increased to 1.3% by mass, and the amount of drying air at the time of the drying process was 150 m ^3. / Hr. In Comparative Example 2, the mixed solvent dehydrated by the organic solvent dehydrator is the outlet in the mixed solvent dehydrated in the solvent dehydration step when the solvent dehydration step → water washing step → drying step is repeated. The average moisture concentration increases.

  This is because the dehydrating material is made of a plurality of spherical cation exchange resins modified with Na sulfonic acid group having a base structure of styrene-divinylbenzene copolymer with a dehydrating strength of 8%. The particle size range is 0.35 mm. Since the particle rate of 0.5 mm and particle size of 0.4 mm or less was 80%, there were many cation exchange resin particles destroyed in the drying process. As a result of the clogging of the obtained filter, it is considered that the dewatering ability of the organic solvent dewatering device was lowered.

(Comparative Example 3)
In the organic solvent dehydrating apparatus shown in FIG. 1, a plurality of spherical cation exchange resins modified with Na sulfonate group having a base structure of styrene-divinylbenzene copolymer with a dehydrating strength of 8% are used. The particle ratio of 0.1 mm to 1.0 mm and a particle size of 0.4 mm or less was 80%. The spherical cation exchange resin was measured using a particle size distribution measuring instrument (HORIBA LA-950V2) based on “Particle Size Analysis Laser Diffraction Method” defined in Japanese Industrial Standard (JIS Z 8825-1). I did it.

  19 kg of this cation exchange resin is filled in the dehydration tank 1, and as a solvent dehydration step, a mixed liquid of 2% by mass of water, 88% by mass of methylene chloride, and 10% by mass of methanol is fed at 200 L / hr from the organic solvent introduction line 3 to be treated. The dehydration tank 1 was introduced. At this time, the adsorption temperature was 30 ° C.

  Next, as a water washing step, 20 L / min of tap water was introduced into the dehydration tank 1 through the water or dry air introduction line 23 to wash the solvent adhering to the dehydrating material. Next, as a drying step, the air volume was adjusted so that the maximum pressure loss of the dehydrating tank 1 did not exceed 90 kPa, and dry heated air of 100 ° C. and 0 ° C. DP (Dew Point (dew point)) was introduced into the dehydrating tank 1.

This solvent dehydration step → water washing step → drying step required 4.5 hr. When this step was repeated 20 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the solvent dehydration step was 0.5 mass%. The amount of drying air at the time of the drying process at this time was 220 m ³ / hr.

Furthermore, when this process was repeated 200 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the solvent dehydration process increased to 0.9% by mass, and the amount of drying air at the time of the drying process was 170 m ^3. / Hr. In this comparative example 3, the mixed solvent dehydrated by the organic solvent dehydrator is the outlet in the mixed solvent dehydrated in the solvent dehydration step when the solvent dehydration step → water washing step → drying step is repeated. The average moisture concentration increases.

  This is because the dehydrating material is made of a plurality of spherical cation exchange resins modified with Na sulfonic acid group having a base structure of styrene-divinylbenzene copolymer with a dehydrating strength of 8%. The particle size range is 0.1 mm. Since the particle ratio of 1.0 mm to 0.4 mm in particle size was 80%, there were many cation exchange resin particles destroyed in the drying process. As a result of the clogging of the obtained filter, it is considered that the dewatering ability of the organic solvent dewatering device was lowered.

  The above-described embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The organic solvent dehydrating apparatus of the present invention is an organic solvent dehydrating apparatus that realizes continuous purification of the solvent, basically does not require replacement of the dehydrating material, and can remove a large amount of water with high efficiency and stability. Without requiring an increase in equipment, the dehydrating material replacement operation can be omitted, and costs can be reduced and moisture can be removed stably. As a result, it can be used for dehydration of the solvent recovered from exhaust gas generated from a wide range of fields such as laboratories and factories using a solvent recovery processing apparatus, and contributes greatly to the industry.

  DESCRIPTION OF SYMBOLS 1 Dehydration tank, 2 Processed organic solvent tank, 3 Processed organic solvent introduction line, 4, 13, 22, 24, 27, 52 Damper, 6 Purified organic solvent discharge line, 7 Purified organic solvent tank, 11 Water tank, 12 Water pump, 21 Compressor, 23 Dry air introduction line, 26 Dry air discharge line, 28 line, 41 Processed gas, 42 Fan, 43 Adsorption tower, 44 Activated carbon fiber element, 45 Steam, 46 Clean gas, 47 Condenser, 48 Separator, 49 Recovery solvent, 51 Washing water circulation path.

Claims (2)

A dehydration process facility that allows the organic solvent to be treated containing water to flow through the dehydrating material filled in the dehydration tank and adsorbs moisture to the dehydrating material, and an inert gas that flows through the dehydrating material and adsorbs to the dehydrating material An organic solvent dehydrating apparatus comprising a drying process facility for drying the water, and alternately performing such a process,
The dehydrating material includes a cation exchange resin having a spherical shape,
The dehydrating material is an organic solvent dehydrating apparatus, wherein the particle ratio of the cation exchange resin having a particle size of 0.4 mm or less is 90% or more.   The matrix structure of the cation exchange resin is at least one selected from the group consisting of an acrylic acid polymer, a methacrylic acid polymer, and a styrene-divinylbenzene copolymer, and the matrix structure includes a carboxylic acid Ca group or a sulfone. The organic solvent dehydrating apparatus according to claim 1, wherein an acid Na group is provided.