JP2013188700A - Organic solvent dehydration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic solvent dehydration device that achieves continuous purification of an organic solvent, and can efficiently and stably eliminate water from a large quantity of organic solvent without basically requiring the replacement of a dehydration material.SOLUTION: An organic solvent dehydration device is configured to dehydrate and eliminate water contained in a treatment object organic solvent by introducing the treatment object organic solvent containing water to a dehydration material to contact with the dehydration material. The dehydration material 11 contains a plurality of spherically-shaped positive ion exchange resin particles. In the dehydration material, the rate of particles having a particle size of 0.4 mm or less of the positive ion exchange resin is 90% or more. The organic solvent dehydration device has: a dehydration tank 15 filled with the dehydration material; a treatment object organic solvent introduction line 13 for introducing the treatment object organic solvent into the dehydration tank; a decompressor 24 that decompresses the interior of the dehydration tank; and a desorbed gas discharge line 27 for discharging from the dehydration tank a gas desorbed within the dehydration tank and introducing it to the decompressor.

Description

  The present invention relates to an apparatus for removing moisture from an organic solvent, and more particularly to an organic solvent dehydration apparatus used for dehydration of 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 organic solvent. That is, the organic solvent can be obtained by heating and evaporating the organic 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, the following Patent Document 2 discloses a dehydration step in which an organic solvent is caused to flow through a dehydrating material filled in a dehydrating tank so that moisture contained in the organic solvent is adsorbed to the dehydrating material, and a dehydrating material. In addition, an organic solvent dehydration apparatus using a cation exchange resin as a dehydrating material has been proposed, which has a desorption step of desorbing moisture absorbed by the dehydrating material by passing an inert gas or air.

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 desorption rate is increased during desorption (drying) of the dehydrating material after the dehydration process, the dehydrating material breaks due to the difference in the water content between the inner and outer layers of the dehydrating material. Is done. As a result, clogging occurs in the filter provided in the dehydration tank due to debris from the dehydrating material, and the dehydrating material is closely packed, resulting in increased pressure loss and reduced desorption efficiency. May reduce ability.

  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 therewith The dehydrating material includes a plurality of cation exchange resins having a spherical shape, the cation exchange resin has a particle size of 0.4% or less and a particle ratio of 90% or more, and is filled with the dehydrating material. A dehydration tank, an organic solvent introduction line for introducing the organic solvent to be treated into the dehydration tank, a decompressor for depressurizing the dehydration tank, and a gas desorbed in the dehydration tank are discharged from the dehydration tank. And a desorption gas discharge line to be introduced into the decompressor.

  In another embodiment, the base structure of the cation exchange resin is a styrene-divinylbenzene copolymer, and is provided with a carboxylic acid group or a sulfonic acid group.

In another form, the dehydrating material heating means for heating the dehydrating material and / or the dehydrating material cooling means for cooling the dehydrating material are included.

In another embodiment, the desorption gas discharge line and / or the gas discharge line from the decompressor is provided with a cooling condensation facility.

In another embodiment, the dehydrating tank has at least two dehydrating tanks, and at least one of the dehydrating tanks is depressurized by a decompressor from a desorption gas discharge line, and the dehydrating material is filled in the dehydrating tank. When the water absorbed by the organic solvent and the dehydrating material adhering to the solvent evaporates and the evaporated organic solvent gas and water vapor are discharged from the desorption gas discharge line, in other dehydration tanks, from the organic solvent introduction line to be treated By introducing the organic solvent to be treated, the organic solvent can be continuously dehydrated.

  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 2 tank type system in the dehydration tank in embodiment. It is a figure which shows the optimal structural example of the dehydration tank in embodiment. It is a figure which shows the organic-solvent gas processing apparatus using activated carbon fiber.

  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 is configured such that an organic solvent containing moisture is passed through a dehydrating material filled in a dehydrating tank and the dehydrating material absorbs moisture, and the dehydrating material is filled. This is an organic solvent dehydrating apparatus that includes a desorption process facility that desorbs moisture absorbed by the dehydrating material by depressurizing the inside of the dehydrating tank using a pressure reducer, and alternately performs such a 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, the dehydrating process and the desorbing process are switched by a damper or the like, and dehydration and desorption 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 absorbed moisture in the dehydrating process moves to the desorption 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, the organic solvent containing water stored in the organic solvent tank 12 to be processed is supplied to the dehydrating material 11 through the organic solvent introduction line 13 via the solvent feed pump 17. The dehydrated organic solvent is sent to the filled dehydration tank 15 and sent to the dehydrated organic solvent tank 14 through the dehydrated organic solvent discharge line 10. A dehydration step of dehydrating the water.

  The dehydrating material 11 in the present embodiment includes a plurality of cation exchange resins having a spherical shape, and the dehydrating material 11 has a particle ratio of 90% or more when the particle size of the cation exchange resin is 0.4 mm or less. Is preferred. The cation exchange resin expands in volume when it absorbs moisture, and has a property that the moisture desorbs and shrinks in volume when the pressure is reduced, and the cation exchange resin may physically crush due to the stress of volume change. This physical crushing stress decreases as the particle size decreases. Under the conditions of the organic solvent dehydrator that continuously absorbs water in the solvent and desorbs it under reduced pressure in the present invention, if the particle size of the cation exchange resin is 0.4 mm or less, crushing hardly occurs. 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, 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. More preferred. Note that the particle ratio means that all the cation exchange resins constituting the dehydration material (cation exchange resin filled in the dehydration tank 15) are 100%, and there are specific particles contained therein. Say percentage.

  The base structure of the cation exchange resin is preferably a styrene-divinylbenzene copolymer having a carboxylic acid group or a sulfonic acid group. In particular, it is more preferable that many sulfonic acid Na groups having high affinity with OH groups are provided. This is because the polymer has high solvent resistance and a strong polymer structure, so that the volume change rate at the time of water absorption and drying is small, so that the cation exchange resin is not easily crushed.

  After the dehydrating material 11 absorbs moisture, the dehydrating tank 15 is depressurized using the decompressor 24, and the mixed gas of the organic solvent adhering to the dehydrating material 11 and the water absorbed by the dehydrating material 11 is discharged as a desorption gas. There is a desorption step of discharging from the line 22 via the pressure reducer 24 through the pressure reducer desorption gas discharge line 27.

  Prior to the desorption step, it is preferable to return the organic solvent to be processed stored in the dehydration tank 15 to the organic solvent tank 12 to be processed from the return line 23. If the organic solvent is stored in the dewatering tank 15 and the process proceeds to the desorption process, not only a large amount of organic solvent may flow into the decompressor 24 but also a large amount of the organic solvent remaining in the dewatering tank 15 needs to be evaporated. This is because the desorption process takes energy and time. Further, since all of the organic solvent to be treated stored in the dehydration tank 15 before the desorption step does not pass through the dehydrating material 11 at a predetermined flow rate, the moisture content is relatively high. Instead, it is preferably returned to the organic solvent tank 12 to be treated.

  In the desorption process, it is preferable to include a dehydrating material heating means for heating the dehydrating material 11. By dehydrating the dehydration tank 15 under reduced pressure, the water and organic solvent evaporate. At this time, the heat energy is taken away from the dehydrating material as the heat of vaporization, and the evaporation rate is slowed. By heating, the evaporation rate is increased, and the time of the desorption process can be shortened.

  Although it is a dehydrating material heating means, it is not particularly limited, but in consideration of the characteristics of an explosive organic solvent, an indirect heating method with high safety is preferable. For example, the structure of the dehydration tank 15 using a shell and tube type heat exchanger as shown in FIG. 2 can be considered. When the dehydrating material 11 is filled in the tube, an organic solvent to be treated is introduced from the lower part of the dehydrating tank 15 to be brought into contact with the dehydrating material 11 in the tube and discharged from the upper part of the dehydrating tank 15 (dehydration process). Thereafter, the organic solvent stored in the dehydration tank 15 is returned to the treated organic solvent tank 12 from below, and the inside of the dehydration tank 15 is depressurized from the bottom of the dehydration tank 15 using a decompressor (desorption process). At this time, the dehydrating material 11 can be indirectly heated efficiently by simultaneously introducing steam from the heat medium introduction line 18 and discharging steam drain from the heat medium discharge line 19. It is also possible to fill the dehydrating material 11 outside the tube in the shell. In this case, the line through which the organic solvent to be treated is introduced and discharged and the line where the pressure is reduced by the decompressor 24 are the heat medium described above. Steam can be introduced into the tube from the upper part of the dewatering tank 15 and discharged from the lower part using the introduction line 18 and the heat medium discharge line 19, and the same effect can be obtained by using an inverse structure. In addition, if it is an indirect heating method, it will not specifically limit to the structure of FIG.

In the desorption process, the desorption gas discharge line 22 and / or the decompressor gas discharge line 27 are preferably provided with a cooling condensation facility.
The mixed gas of the organic solvent and water evaporated by depressurizing the dehydration tank 15 condenses a part of the mixed gas in the desorption gas discharge line 22, thereby reducing the amount of gas introduced into the decompressor 24. The desorption efficiency can be increased and the desorption process can be shortened. In addition, by providing a cooling and condensing facility in the decompressor gas discharge line 27, it is possible to recover the evaporated organic solvent, and by separating it from moisture, returning it to the organic solvent tank 12 to be processed, It is possible to improve the yield of the organic solvent.
When the desorption gas discharge line 22 and / or the decompressor gas discharge line 27 is provided with a cooling condensing facility, the condensed water / solvent mixture is stored in the condensate tank 26 and optionally separated into water and solvent. It can be returned to the processing solvent tank 12.
More preferably, the desorption gas discharge line 22 and the decompressor gas discharge line 27 are provided with a cooling condensing facility.

  The gas generated by the desorption process contains a trace amount of an organic solvent, and the gas discharged from the decompressor gas discharge line 27 is used as a combustion device such as a direct combustion device, a catalytic combustion device, a regenerative combustion device, or an activated carbon fiber. It can process with the gas processing apparatus generally used, such as the solvent recovery apparatus which used this.

  In the desorption step, nitrogen 20 is preferably introduced into the dehydration tank 15 through the nitrogen introduction line 21. By introducing nitrogen 20, the oxygen concentration in the dehydration tank 15 can be reduced to reduce the risk of explosion, and further, an air flow is generated in the dehydration tank and the heat conduction effect during indirect heating is increased. This is because the efficiency can be improved and the time of the desorption process can be shortened.

  By repeating the above dehydration step → desorption step continuously, the apparatus can effectively and economically dehydrate and remove water from the organic solvent containing water. By such continuous dehydration-desorption under reduced pressure, moisture in the organic solvent can be removed stably at a low cost with a high capacity. Furthermore, it is preferable to have a dehydrating material cooling means for cooling the dehydrating material 11 when moving from the desorption process to the dehydrating process. This is because when an organic solvent is introduced into the dehydrating tank 15 in a high temperature state, a large amount of the organic solvent is vaporized in a short time, causing a pressurized state in the dehydrating tank 15 and increasing the risk of explosion. Moreover, it is because the dehydration effect by the dehydrating material 11 becomes low, so that the temperature of the to-be-processed organic solvent containing water is high. The dehydrating material cooling means is not particularly limited, but a highly safe indirect cooling method is preferable. For example, the structure of the dehydration tank 15 using a shell and tube type heat exchanger as shown in FIG. 2 can be considered. When the dehydrating material 11 is filled in the tube, an organic solvent to be treated is introduced from the lower part of the dehydrating tank 15 to be brought into contact with the dehydrating material 11 in the tube and discharged from the upper part of the dehydrating tank 15 (dehydration process). Thereafter, the organic solvent stored in the dehydration tank 15 is returned to the treated organic solvent tank 12 from below, and the inside of the dehydration tank 15 is depressurized from the bottom of the dehydration tank 15 using a decompressor (desorption process). Thereafter, cooling water, cold water or cooling air is introduced from the heat medium introduction line 18 and discharged from the heat medium discharge line 19, whereby the dehydrating material 11 can be indirectly cooled efficiently. It is also possible to fill the dehydrating material 11 outside the tube in the shell. In this case, the line through which the organic solvent to be treated is introduced and discharged and the line where the pressure is reduced by the decompressor 24 are the heat medium described above. Using the introduction line 18 and the heat medium discharge line 19, cooling water, cold water or cooling air can be introduced into the tube from the upper or lower part of the dewatering tank 15 and discharged from the lower part or upper part. It is also possible to obtain an effect.

  The operation of the dehydrating material 11 according to the present embodiment preferably employs a continuously removable system provided with two or more dewatering tanks 15 as shown in FIG. Considering the amount of the organic solvent and the like, intermittent operation may be performed, or one dehydration tank may be used. 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 capable of dehydration in the present embodiment is not particularly limited to ethyl acetate, methyl acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, methylene chloride, chloroform, dichloromethane and the like, and mixtures thereof. Applicable in organic solvents.

  The organic solvent that can be dehydrated in the present embodiment is an organic solvent that recovers a gas containing an organic solvent discharged from factories in various fields, such as a dry laminating process for laminating films, using an organic solvent recovery processing device. It can also be applied to solvents.

  For example, in the 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 treated is introduced from the fan 42 and filled in the adsorption tower 43, and the outside air is used as the clean gas 46. The organic solvent is desorbed by introducing the steam 45 into the activated carbon fiber element 44, and the condenser 48 is cooled and condensed by the condenser 48, and the solvent and water are separated by the separator 49, and the recovered solvent 50 is recovered. There is a desorption process, and it is a system that can be continuously processed by alternately performing an adsorption process and a 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.

  When the organic solvent recovered by the organic solvent recovery processing apparatus shown in FIG. 3 is dehydrated by the organic solvent dehydrating apparatus shown in FIG. 1, it is discharged from the decompressor gas discharge line 27 of the organic solvent dehydrating apparatus shown in FIG. The mixed gas of the organic solvent gas and water vapor is returned to the gas 41 to be processed shown in FIG. 3 to improve the yield of the organic solvent and is more economical.

  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. . Table 1 shows various conditions of the dehydrating materials 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 plurality of spherical cation exchange resins in which the dehydrating material 11 is modified with a sulfonic acid Na group having a base structure of a styrene-divinylbenzene copolymer having a rack strength of 8% are used. The particle ratio of 0.2 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.

  1.9 kg of this cation exchange resin is filled in the dehydration tank 15, and as a dehydration process, a mixed liquid of 3% by weight of water and 97% by weight of ethyl acetate is fed into the dehydration tank 15 from the treated organic solvent introduction line 13 at 20 L / hr. The organic solvent which was introduced and dehydrated in the dehydrated organic solvent tank 14 was obtained. The temperature of the organic solvent around the dehydrating material 11 during the dehydration step 2.5 hr was 30 ° C.

  Next, after the organic solvent filled in the dehydration tank 15 was discharged to the organic solvent tank 12 to be treated, the dehydration tank 15 was depressurized at 150 Torr using the decompressor 24 as a desorption process. During the desorption process 5 hr, nitrogen 20 was introduced from the nitrogen introduction line 21 at 1 L / hr.

  The dehydration step → desorption step takes 7.5 hours in total. When this step was repeated 20 cycles, the average water concentration at the outlet in the organic solvent dehydrated in the dehydration step was reduced to 0.9 wt%.

  Furthermore, when this step was repeated 200 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the dehydration step was reduced to 0.9% by weight, as in the 20th cycle. At this time, the average particle size of the cation exchange resin of the dehydrating material 11 is 0.35 mm to 0.33 mm as compared with 0 cycle, and the particle ratio of the particle size of 0.4 mm or less is also changed from 90% to 91%, almost changing. There was no. Thus, the organic solvent dehydrated by the organic solvent dehydrating apparatus in Example 1 has an average water concentration at the outlet of 0.9% by weight in the dehydrated mixed solvent even if the dehydration step → desorption step is repeated. It was possible to maintain it, and there was no degradation in performance, and dewatering treatment was possible stably and with high efficiency.

  This is a spherical cation exchange resin in which the dehydrating material 11 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 0.2 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 desorption process, and the filter provided in the dehydration tank was clogged with debris. Further, the dehydration ability of the organic solvent dehydrating apparatus is maintained without decreasing the desorption efficiency due to the pressure loss increasing due to the cation exchange resin being closely packed with the dehydrated material 11 fragments.

(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.

  1.9 kg of this cation exchange resin is filled in the dehydration tank 15, and as a dehydration step, a mixed liquid of 3% by weight of water, 80% by weight of ethyl acetate, and 17% by weight of n-propyl acetate is treated with an organic solvent at 20 L / hr. The organic solvent introduced into the dehydration tank 15 from the introduction line 13 and dehydrated in the dehydrated organic solvent tank 14 was obtained. The temperature of the organic solvent around the dehydrating material 11 during the dehydration step 2.5 hr was 30 ° C.

  Next, after the organic solvent filled in the dehydration tank 15 was discharged to the organic solvent tank 12 to be treated, the dehydration tank 15 was depressurized at 150 Torr using the decompressor 24 as a desorption process. At this time, the dehydration tank 15 uses the structure shown in FIG. 2, in order to heat the dehydrating material 11 filled in the tube, steam of 0.1 MPa is supplied from the heating medium supply line 18, and nitrogen 20 Was introduced from the nitrogen introduction line 21 at 1 L / hr. After 2 hours, the steam supplied from the heating medium supply line 18 was stopped, cooling water was introduced, and the dehydration tank 15 was cooled for 0.5 hours.

  The dehydration step → desorption step required 5 hr in total, and when this step was repeated 20 cycles, the average moisture concentration at the outlet in the organic solvent dehydrated in the dehydration step was reduced to 0.95 wt%.

  Furthermore, when this process was repeated 200 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the dehydration process was reduced to 0.95 wt%, as in the 20th cycle. At this time, the average particle size of the cation exchange resin of the dehydrating material 11 is 0.3 mm to 0.28 mm compared to 0 cycle, and the particle ratio of the particle size of 0.4 mm or less is also changed from 90% to 93%, almost changing. There was no. As a result, the organic solvent dehydrated by the organic solvent dehydrating apparatus in Example 2 has an average outlet water concentration of 0.95 wt% in the dehydrated mixed solvent even if the dehydration step → desorption step is repeated. It was possible to maintain it, and there was no degradation in performance, and dewatering treatment was possible stably and with high efficiency.

  This is a spherical cation exchange resin in which the dehydrating material 11 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 desorption process, and the filter provided in the dehydration tank was clogged with debris. Further, the dehydration ability of the organic solvent dehydrating apparatus is maintained without decreasing the desorption efficiency due to the pressure loss increasing due to the cation exchange resin being closely packed with the dehydrated material 11 fragments.

(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.

  1.9 kg of this cation exchange resin is filled in the dehydration tank 15, and as a dehydration step, a mixed liquid of 2% by weight of water, 88% by weight of methylene chloride and 10% by weight of methanol is treated with an organic solvent introduction line 13 at 20 L / hr. The organic solvent was further introduced into the dehydration tank 15 and dehydrated into the dehydrated organic solvent tank 14. The temperature of the organic solvent around the dehydrating material 11 during the dehydration step 2.5 hr was 30 ° C.

  Next, after the organic solvent filled in the dehydration tank 15 was discharged to the organic solvent tank 12 to be treated, the dehydration tank 15 was depressurized at 150 Torr using the decompressor 24 as a desorption process. At this time, the dehydration tank 15 uses the structure shown in FIG. 2, in order to heat the dehydrating material 11 filled in the tube, steam of 0.1 MPa is supplied from the heating medium supply line 18, and nitrogen 20 Was introduced from the nitrogen introduction line 21 at 1 L / hr. After 2 hours, the steam supplied from the heating medium supply line 18 was stopped, cooling water was introduced, and the dehydration tank 15 was cooled for 0.5 hours.

  The dehydration step → desorption step takes 5 hours in total, and when this step was repeated 20 cycles, the average water concentration at the outlet in the organic solvent dehydrated in the dehydration step was reduced to 0.5% by weight.

  Furthermore, when this step was repeated 200 cycles, the average water concentration at the outlet in the mixed solvent dehydrated in the dehydration step was reduced to 0.5% by weight as in the case of the 20 cycles. At this time, the average particle diameter of the cation exchange resin of the dehydrating material 11 was 0.39 mm to 0.38 mm as compared with 0 cycle, and there was almost no change. Thus, the organic solvent dehydrated by the organic solvent dehydrating apparatus in Example 3 has an average water concentration of 0.5% by weight at the outlet in the dehydrated mixed solvent even when the dehydration step → desorption step is repeated. It was possible to maintain it, and there was no degradation in performance, and dewatering treatment was possible stably and with high efficiency.

  This is a spherical cation exchange resin in which the dehydrating material 11 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 desorption process, and the filter provided in the dehydration tank was clogged with debris. Further, the dehydration ability of the organic solvent dehydrating apparatus is maintained without decreasing the desorption efficiency due to the pressure loss increasing due to the cation exchange resin being closely packed with the dehydrated material 11 fragments.

(Comparative Example 1)
In the organic solvent dehydrating apparatus shown in FIG. 1, a plurality of spherical cation exchange resins in which the dehydrating material 11 is modified with a sulfonic acid Na group having a base structure of a styrene-divinylbenzene copolymer having a rack strength of 8% are used. The particle ratio of 0.6 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.

  1.9 kg of this cation exchange resin is filled in the dehydration tank 15, and as a dehydration process, a mixed liquid of 3% by weight of water and 97% by weight of ethyl acetate is fed into the dehydration tank 15 from the treated organic solvent introduction line 13 at 20 L / hr. The organic solvent which was introduced and dehydrated in the dehydrated organic solvent tank 14 was obtained. The temperature of the organic solvent around the dehydrating material 11 during the dehydration step 2.5 hr was 30 ° C.

  Next, after the organic solvent filled in the dehydration tank 15 was discharged to the organic solvent tank 12 to be treated, the dehydration tank 15 was depressurized at 150 Torr using the decompressor 24 as a desorption process. During the desorption process 5 hr, nitrogen 20 was introduced from the nitrogen introduction line 21 at 1 L / hr.

  The dehydration step → desorption step takes 7.5 hours in total. When this step was repeated 20 cycles, the average water concentration at the outlet in the organic solvent dehydrated in the dehydration step was reduced to 0.9 wt%.

  Furthermore, when this process was repeated 200 cycles, it increased compared to the average moisture concentration at 20 cycles, and the average moisture concentration at the outlet in the mixed solvent dehydrated in the dehydration step was up to 1.7% by weight. Rose. At this time, the average particle size of the cation exchange resin of the dehydrating material 11 is 0.65 mm to 0.41 mm compared to 0 cycle, and the particle size of the particle size of 0.4 mm or less is also 0% to 80%. It was confirmed that it was getting smaller. As a result, the organic solvent dehydrated by the organic solvent dehydrating apparatus in Comparative Example 1 increased the average water concentration at the outlet in the dehydrated mixed solvent by repeating the dehydration step → the desorption step. Decline was confirmed.

  This is a spherical cation exchange resin in which the dehydrating material 11 is modified with a sulfonic acid Na group whose base structure is a styrene-divinylbenzene copolymer having a rack strength of 8%, but the particle size range is 0.6 to 0.7 mm. Since the particle ratio of 0.4 mm or less was 0%, the cation exchange resin was destroyed over time even in the desorption process due to the relatively large particle size, which was caused by dehydrated debris. This is because clogging occurs in the filter provided in the dehydration tank, or the cation exchange resin is closely packed with the debris 11 to increase the pressure loss, thereby reducing the desorption efficiency.

(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 50%. 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.

  1.9 kg of this cation exchange resin is filled in the dehydration tank 15, and as a dehydration step, a mixed liquid of 3% by weight of water, 80% by weight of ethyl acetate, and 17% by weight of n-propyl acetate is treated with an organic solvent at 20 L / hr. The organic solvent introduced into the dehydration tank 15 from the introduction line 13 and dehydrated in the dehydrated organic solvent tank 14 was obtained. The temperature of the organic solvent around the dehydrating material 11 during the dehydration step 2.5 hr was 30 ° C.

  Next, after the organic solvent filled in the dehydration tank 15 was discharged to the organic solvent tank 12 to be treated, the dehydration tank 15 was depressurized at 150 Torr using the decompressor 24 as a desorption process. At this time, the dehydration tank 15 uses the structure shown in FIG. 2, in order to heat the dehydrating material 11 filled in the tube, steam of 0.1 MPa is supplied from the heating medium supply line 18, and nitrogen 20 Was introduced from the nitrogen introduction line 21 at 1 L / hr. After 2 hours, the steam supplied from the heating medium supply line 18 was stopped, cooling water was introduced, and the dehydration tank 15 was cooled for 0.5 hours.

  The dehydration step → desorption step required 5 hr in total, and when this step was repeated 20 cycles, the average moisture concentration at the outlet in the organic solvent dehydrated in the dehydration step was reduced to 0.95 wt%.

  Furthermore, when this process was repeated 200 cycles, it increased compared to the average moisture concentration at the time of 20 cycles, and the average moisture concentration at the outlet in the mixed solvent dehydrated in the dehydration step was 1.35% by weight. Rose. At this time, the average particle size of the cation exchange resin of the dehydrating material 11 is 0.4 mm to 0.35 mm as compared to 0 cycle, and the particle size of the particle size of 0.4 mm or less is also 50% to 75%. It was confirmed that it was getting smaller. As a result, the organic solvent dehydrated by the organic solvent dehydrating apparatus in Comparative Example 2 increased the average water concentration at the outlet in the dehydrated mixed solvent by repeating the dehydration step → the desorption step. Decline was confirmed.

  This is a spherical cation exchange resin in which the dehydrating material 11 is modified with a sulfonic acid Na group having a base structure of a styrene-divinylbenzene copolymer having a rack strength of 8%, but the particle size range is 0.35 to 0.5 mm. In the desorption step, the cation exchange resin was destroyed over time due to the relatively large particle size because the particle ratio of the particle size of 0.4 mm or less was 50%. This is because clogging occurs in the filter provided in the dehydration tank, or the cation exchange resin is closely packed with the debris 11 to increase the pressure loss, thereby reducing the desorption efficiency.

(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.

  1.9 kg of this cation exchange resin is filled in the dehydration tank 15, and as a dehydration step, a mixed liquid of 2% by weight of water, 88% by weight of methylene chloride and 10% by weight of methanol is treated with an organic solvent introduction line 13 at 20 L / hr. The organic solvent was further introduced into the dehydration tank 15 and dehydrated into the dehydrated organic solvent tank 14. The temperature of the organic solvent around the dehydrating material 11 during the dehydration step 2.5 hr was 30 ° C.

  Next, after the organic solvent filled in the dehydration tank 15 was discharged to the organic solvent tank 12 to be treated, the dehydration tank 15 was depressurized at 150 Torr using the decompressor 24 as a desorption process. At this time, the dehydration tank 15 uses the structure shown in FIG. 2, in order to heat the dehydrating material 11 filled in the tube, steam of 0.1 MPa is supplied from the heating medium supply line 18, and nitrogen 20 Was introduced from the nitrogen introduction line 21 at 1 L / hr. After 2 hours, the steam supplied from the heating medium supply line 18 was stopped, cooling water was introduced, and the dehydration tank 15 was cooled for 0.5 hours.

  The dehydration step → desorption step takes 5 hours in total, and when this step was repeated 20 cycles, the average water concentration at the outlet in the organic solvent dehydrated in the dehydration step was reduced to 0.5% by weight.

  Furthermore, when this process was repeated 200 cycles, it increased compared to the average moisture concentration at the time of 20 cycles, and the average moisture concentration at the outlet in the mixed solvent dehydrated in the dehydration step was up to 0.75% by weight. Rose. At this time, the average particle size of the cation exchange resin of the dehydrating material 11 is from 0.5 mm to 0.39 mm as compared with 0 cycle, and the particle size of the particle size of 0.4 mm or less is 80% to 90%. It was confirmed that it was getting smaller. As a result, the organic solvent dehydrated by the organic solvent dehydrating apparatus in Comparative Example 3 increased the average water concentration at the outlet in the dehydrated mixed solvent by repeating the dehydration step → the desorption step. Decline was confirmed.

  This is a spherical cation exchange resin in which the dehydrating material 11 is modified with a sulfonic acid Na group having a base structure of a styrene-divinylbenzene copolymer having a rack strength of 8%, but the particle size range is 0.15 to 1.0 mm. In the desorption process, the cation exchange resin was destroyed over time due to the relatively large particle size, and the particle ratio of 0.4 mm or less was 80%. This is because clogging occurs in the filter provided in the dehydration tank, or the cation exchange resin is closely packed with the debris 11 to increase the pressure loss, thereby reducing the desorption efficiency.

  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 10 Dehydrated organic solvent discharge line 11 Dehydrated material 12 Processed organic solvent tank 13 Processed organic solvent introduction line 14 Dehydrated organic solvent tank 15 Dehydration tank 16 Dehydration tank heating / cooling equipment 17 Solvent feed pump 18 Heat medium introduction Line 19 Heat medium discharge line 20 Nitrogen 21 Nitrogen introduction line 22 Desorption gas discharge line 23 Return line 24 Decompression machine 25 Condensate tank 27 Decompression machine gas discharge line 41 Gas to be treated 42 Fan 43 Adsorption tower 44 Activated carbon fiber element 45 Steam 46 Clean gas 47 Damper 48 Condenser 49 Separator 50 Recovered solvent

Claims (5)

An organic solvent dehydrating apparatus for dehydrating and removing moisture contained in the organic solvent to be treated by introducing and contacting the organic solvent to be treated containing moisture to the dehydrating material,
The dehydrating material includes a plurality of cation exchange resins having a spherical shape,
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,
A dehydrating tank filled with the dehydrating material;
A treated organic solvent introduction line for introducing the treated organic solvent into the dewatering tank;
A decompressor for decompressing the inside of the dehydration tank;
A desorption gas discharge line for discharging the gas desorbed in the dehydration tank from the dehydration tank and introducing it into the decompressor;
Organic solvent dehydrator.   The organic solvent dehydration apparatus according to claim 1, wherein the base structure of the cation exchange resin is a styrene-divinylbenzene copolymer, to which a carboxylic acid group or a sulfonic acid group is added.   The organic solvent dehydrating apparatus according to claim 1, further comprising a dehydrating material heating unit that heats the dehydrating material and / or a dehydrating material cooling unit that cools the dehydrating material.   The organic solvent dehydration apparatus according to any one of claims 1 to 3, wherein the desorption gas discharge line and / or the gas discharge line from the decompressor is provided with a cooling condensation facility.   There are at least two dehydration tanks, and at least one of the dehydration tanks is depressurized by a decompressor from the desorption gas discharge line, and the organic solvent adhering to the dehydrating material filled in the dehydration tank is dehydrated. When the water absorbed by the material is evaporated and the organic solvent gas and water vapor are discharged from the desorption gas discharge line, the organic solvent to be processed is introduced from the organic solvent introduction line to be treated in other dehydration tanks. The organic solvent dehydrating apparatus according to claim 1, wherein the organic solvent can be continuously dehydrated.