JP2009291676A - Solvent refining apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus continuously refining an organic solvent, and stably removing moisture from a large amount of the organic solvent, dispensing with replacement of an adsorbent basically. <P>SOLUTION: The solvent refining apparatus includes an adsorbing process of adsorbing moisture contained in the organic solvent by passing the organic solvent through the adsorbent filled in an adsorbing tower, and a desorbing process of desorbing the moisture adsorbed in the adsorbent by passing inert gas or air through the adsorbent. The adsorbent comprises at least one or more of ion exchange resin, activated alumina, molecule sieves and silica gel. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus for purifying a solvent by removing moisture from an organic solvent, and more particularly, an apparatus used for purifying an organic solvent recovered from an organic solvent-containing gas generated from various factories or research facilities using a solvent recovery apparatus. It is.

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

However, 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 is known in which impurities are removed by passing an organic solvent through an adsorption tower packed with an adsorbent such as zeolite, ion exchange resin, molecular sieves, and activated alumina (for example, Patent Documents). 1). However, when purifying a large amount of organic solvent, a large amount of adsorbent is required, and when the adsorbent becomes a breakthrough state, it is necessary to replace the adsorbent, which increases the labor for replacing the adsorbent and the running cost. . Therefore, although it is an effective means at the laboratory level, it is not satisfactory for purifying a large amount of organic solvent recovered from factories or research facilities.

JP 2000-225316 A

  The present invention has been made against the background of the problems of the prior art, realizes continuous purification of organic solvents, and basically eliminates the need for replacement of adsorbents and stably removes moisture from a large amount of organic solvents. It is an object of the present invention to provide an apparatus capable of performing the above.

In order to solve the problems of the prior art, the present invention has finally been completed as a result of intensive studies. That is, the present invention is as follows.
1. An adsorbing step for adsorbing moisture contained in the organic solvent to the adsorbent by passing the organic solvent through the adsorbent packed in the adsorption tower; and an inert gas or air to the adsorbent And a desorption step of desorbing moisture adsorbed on the adsorbent by passing it through, wherein the adsorbent is at least one of ion exchange resin, activated alumina, molecular sieves, and silica gel.
2. 2. The solvent according to 1 above, having a desorption gas introduction path for introducing an inert gas or air into the adsorbent, and having a unit capable of drying and / or heating the deactivation gas or air in the desorption gas introduction path. Purification equipment.
3. 3. The solvent purification apparatus according to 2 above, having a water purge introduction path for introducing water into the adsorbent.
4). When there are at least two adsorption towers and one of the towers introduces the desorption gas from the desorption gas introduction path, the other towers continuously introduce the organic solvent from the treated organic solvent introduction path. 2. The solvent purification apparatus according to 1 above, wherein the organic solvent can be purified.
5. 5. The solvent purifier according to any one of 1 to 4 above, wherein the adsorbent is an ion exchange resin and is a cation exchange resin having at least one of a hydrogen ion form, a sodium form, and an alkanolamine form.
6). 6. The solvent purification apparatus according to 5 above, wherein the cation exchange resin is granular or fibrous.

  The solvent refining apparatus according to the present invention can remove a large amount of water continuously with high efficiency, and basically does not require replacement of the adsorbent, so that it can be stably produced at high cost in an organic solvent at low cost. There is an advantage that the water can be removed and the organic solvent can be purified.

  The solvent refining apparatus according to the present invention includes an adsorption process facility for allowing an organic solvent containing moisture to flow through an adsorbent packed in an adsorption tower and adsorbing moisture to the adsorbent, and passing dry air through the adsorbent. It is preferable that the apparatus is equipped with a desorption process facility for desorbing moisture adsorbed on the adsorbent by flowing it and alternately performing such a process. This is because the processing can be continuously performed by adopting such a structure.

  As a more preferable apparatus structure, the adsorbent is divided into several parts, the adsorption process and the desorption process are switched by a damper or the like, and the solvent purification apparatus performs adsorption and desorption continuously, Alternatively, the adsorbent can rotate, and the solvent refining apparatus has a structure in which a portion of the adsorbent that has adsorbed the organic substance in the adsorption process moves to the desorption process by the rotation of the adsorbent.

Hereinafter, a solvent purification 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 solvent refining apparatus illustrated in FIG. 1, when the organic solvent containing moisture is in a state where the dampers 4 and 5 are opened, the adsorbent is supplied from the stored organic solvent tank 2 through the organic solvent introduction line 3 to be processed. Adsorption process for refining the organic solvent by adsorbing and removing moisture by the adsorbent by sending it to the packed adsorption tower 1 and sending the purified organic solvent to the purified organic solvent tank 7 through the purified organic solvent discharge line 6 Have

  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, water is supplied to the adsorption tower 1 from the water tank 11 through the water or dry air introduction line 23 using the water pump 12. It is preferable to have a water purging step for removing the organic solvent adhering and remaining on the surface of the adsorbent by flowing water. This may be performed by using an inert gas such as nitrogen without performing the water purge process, but the desorption process described later may be performed, 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 purge step, the purge water discharged from the water or desorption 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 adsorption tower 1 through the water or the dry air introduction line 23. It is preferable to have a desorption step of desorbing the adsorbed moisture. The gas generated by the desorption process contains a trace amount of organic solvent, and the gas discharged from the water or desorption air discharge line 26 is directly converted into a combustion apparatus such as a direct combustion apparatus, a catalytic combustion apparatus, a regenerative combustion apparatus, 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 desorption process, 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 desorption time for desorbing moisture from the adsorbent. 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 desorption air by installing an air dryer or the like downstream of the compressor 21. Alternatively, it is more preferable to heat the desorption 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 desorption gas by combining an air dryer or the like with a heater or the like.

  By continuously repeating the above-described adsorption process → water purge process → desorption process, it becomes an apparatus capable of effectively and economically removing moisture from an organic solvent containing moisture. By such continuous adsorption-dry air desorption, moisture in the organic solvent can be removed stably at a low cost and with a high capacity.

  The adsorbent according to the present invention is not particularly limited, such as zeolite, activated alumina, silica gel, ion exchange resin, etc., but is preferably a cation exchange resin from the viewpoint of performance. In other words, the cation exchange resin is an effective water adsorbent having a feature that it can adsorb only water without adsorbing the organic solvent because it has ion exchange groups such as sulfonic acid groups on the resin surface. Also, the adsorption mechanism is different from zeolite, silica gel or activated alumina, and the cation exchange resin absorbs moisture into the resin and swells in the gel, so it is an effective moisture adsorbent with a very large moisture adsorption capacity. .

  The structure of the adsorbent according to the present invention is not particularly limited, such as granular, powdery, porous, honeycomb, and fibrous, but granular or fibrous is particularly preferable. In other words, when the organic solvent containing moisture passes through the adsorbent, the larger the surface area of the adsorbent, the higher the contact efficiency between the adsorbent and the moisture, so that the particulate or fiber has a structure that increases the moisture adsorption capacity. This is because the shape is preferable.

  As for the operation of the adsorbent according to the present invention, it is preferable to employ a continuously removable system provided with two or more adsorption towers as shown in FIG. 2, but the amount of moisture to be removed and the amount of organic solvent to be treated. The intermittent operation may be taken into consideration. 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 purified in the present invention 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. .

The organic solvent that can be purified in the present invention is a gas containing an organic solvent discharged from factories in various fields, such as a dry laminating process for laminating films, and an organic solvent recovered using a solvent recovery processing device. Adaptable.
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. And the organic solvent is desorbed by introducing steam 45 into the activated carbon fiber element 44, cooled and condensed by the condenser 47, the solvent and water are separated by the separator 48, and the recovered solvent 49 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. This type of solvent recovery processing equipment uses steam for desorption, and because water is mixed into the recovered solvent due to cooling and condensation, applying the device in the present invention effectively removes water from the recovered solvent. Can be removed.

EXAMPLES Hereinafter, although the detail of this invention is further demonstrated from an Example, this invention is not limited to these Examples.
The evaluation was performed by the following method.
(Evaluation method for removing water from organic solvents)
Various organic solvents containing water having a concentration of 3% by weight were flowed at a constant flow rate, and the moisture concentration in the purified organic solvent sampled from the purified organic solvent discharge line 6 was measured.
(Water concentration evaluation method)
The moisture concentration at the inlet and outlet of the adsorbent was analyzed and measured by the Karl Fischer moisture measurement method.
(Method for evaluating solvent concentration in water)
The concentration of the solvent (ethyl acetate, methylene chloride) in the purge water at the adsorbent outlet was analyzed and measured by ion chromatography analysis.

[Example 1]
An adsorption tower of 1.5 mmφ and 90 mm thickness is packed with 15 g of adsorbent of a cation exchange resin (Na type, sulfonic acid group, Muromac DW2-1, manufactured by Muromachi Technos Co., Ltd.) having an average particle size of 1 mm. Assembling into the system flow of the 1 tank type solvent refining apparatus, ethyl acetate containing 3% by weight of water was introduced. As a result of confirming the time-dependent change of the outlet moisture concentration at that time, when SV = 20 (1 / h), the initial outlet moisture concentration was 0.1% by weight, and the moisture until the outlet moisture concentration reached 1% by weight. The adsorption amount (q *) was 0.6 (g / g-resin), indicating a good moisture adsorption amount.

Next, as a water purge step, water was introduced into the adsorption tower from the water purge introduction path. When the ethyl acetate concentration in the outlet water at that time is measured, when SV = 20 (1 / h), 95% or more of ethyl acetate adhering to the adsorbent can be removed with an amount of water four times the adsorbent volume. Good removal performance was shown.
Subsequently, dry air at 20 ° C. and −40 ° C. DP was used as the desorption gas in the desorption step, and the desorption SV was 20000 (1 / h). The adsorption time in the adsorption process was 1 h, the time in the water purge process was 10 min, the desorption time in the desorption process was 4 h, and the adsorption / desorption cycle was set. At that time, the outlet average water concentration in ethyl acetate was 0.7% by weight or less.

  The ethyl acetate purified by the solvent purifying apparatus of this example maintains the outlet average water concentration in the ethyl acetate of 0.7% by weight or less even when the adsorption / desorption cycle of the adsorption process → water purge process → desorption process is repeated. It was possible. Since adsorption and desorption are continuously purified, there was no degradation in performance, and purification was possible with high efficiency.

[Example 2]
An adsorption tower of 1.5 mmφ and 90 mm thickness is packed with 15 g of adsorbent of a cation exchange resin (Na type, sulfonic acid group, Muromac DW2-1, manufactured by Muromachi Technos Co., Ltd.) having an average particle size of 1 mm. The methylene chloride containing 3% by weight of water was assembled into the system flow of the one tank type solvent refining apparatus. As a result of confirming the time-dependent change of the outlet moisture concentration at that time, when SV = 2.5 (1 / h), the initial outlet moisture concentration was 0.04 wt%, and the outlet moisture concentration was 0.15 wt%. The moisture adsorption amount (q *) to reach 0.35 (g / g-resin) showed a good moisture adsorption amount.

Next, as a water purge step, water was introduced into the adsorption tower from the water purge introduction path. When the methylene chloride concentration in the outlet water at that time was measured, when SV = 20 (1 / h), 95% or more of methylene chloride adhering to the adsorbent could be removed with an amount of water four times the adsorbent volume. Good removal performance was shown.
Subsequently, dry air at 50 ° C. and −10 ° C. DP was used as a desorption gas in the desorption step, and the desorption SV was 2000 (1 / h). The adsorption cycle in the adsorption process was 1 h, the time in the water purge process was 10 min, the desorption time in the desorption process was 10 h, and a switching cycle was set. At that time, the outlet average water concentration in methylene chloride was 0.1% by weight or less.

  The methylene chloride purified by the solvent refining apparatus of this example maintains the outlet average water concentration in the methylene chloride of 0.15% by weight or less even when the adsorption / desorption cycle of the adsorption step → water purge step → desorption step is repeated. It was possible. Since the adsorption and desorption are continuously purified, there is no degradation in performance and the purification can be performed stably and with high efficiency.

[Example 3]
Two adsorption towers of 1.5 mmφ and 90 mm thickness are filled with 15 g of adsorbent of cation exchange resin (Na type, sulfonic acid group, Muromac DW2-1, manufactured by Muromachi Technos Co., Ltd.) having an average particle size of 1 mm. 2 was assembled into the system flow of the two-tank solvent purifier shown in FIG. 2 and ethyl acetate containing 3% by weight of water was introduced. As a result of confirming the time-dependent change of the outlet moisture concentration at that time, when SV = 2.5 (1 / h), the initial outlet moisture concentration was 0.04 wt%, and the outlet moisture concentration reached 1 wt%. The moisture adsorption amount (q *) was 0.7 (g / g-resin), indicating a good moisture adsorption amount.

Next, as a water purge step, water was introduced into the adsorption tower from the water purge introduction path. When the ethyl acetate concentration in the outlet water at that time is measured, when SV = 20 (1 / h), 95% or more of ethyl acetate adhering to the adsorbent can be removed with an amount of water four times the adsorbent volume. Good removal performance was shown.
Subsequently, dry air at 5 ° C. and −40 ° C. DP was used as a desorption gas in the desorption step, and the desorption SV was set to 1000 (1 / h). Assuming that the solvent to be treated is supplied for 8 hours a day from the factory line, the adsorption time is 8h, the adsorption idle time is 16h, the adsorption process is 24h, the time in the water purge process is 10min, the desorption process The desorption time was 23.8 h, and the water purge + desorption process was combined for 24 h to make an adsorption / desorption cycle. When one adsorption tower was an adsorption process, the other adsorption tower performed the desorption process. At that time, the outlet average water concentration in ethyl acetate was 0.7% by weight or less.

  The ethyl acetate purified by the solvent purifying apparatus of this example maintains the average outlet water concentration of 0.7% by weight or less in the ethyl acetate even when the adsorption / desorption cycle of the adsorption process → water purge process → desorption process is repeated. It was possible. Since the adsorption and desorption are continuously purified in two adsorption towers alternately, the performance can be stably and highly purified without degradation in performance.

[Example 4]
An adsorption tower having a diameter of 1.5 mm and a thickness of 90 mm is filled with 15 g of an adsorbent of a cation exchange resin (Na type, sulfonic acid group, Muromac DW2-1, manufactured by Muromachi Technos Co., Ltd.) having an average particle size of 1 mm. Recovered organic solvent (main 3 components: 95% by weight ethyl acetate, 3 moisture) 0.0 wt%, toluene 1.8 wt%). As a result of confirming the time-dependent change of the outlet moisture concentration at that time, when SV = 2.5 (1 / h), the initial outlet moisture concentration was 0.04 wt%, and the outlet moisture concentration reached 1 wt%. The moisture adsorption amount (q *) was 0.7 (g / g-resin), indicating a good moisture adsorption amount.

Next, as a water purge step, water was introduced into the adsorption tower from the water purge introduction path. At that time, when the concentration of ethyl acetate as the main component of the recovered organic solvent in the purge water was measured, when SV = 20 (1 / h), the amount of water adhering to the adsorbent was 4 times the amount of adsorbent volume. The removal performance of 95% or more of ethyl acetate and good removal performance were shown.
Subsequently, dry air at 20 ° C. and −40 ° C. DP was used as the desorption gas in the desorption step, and the desorption SV was set to 1000 (1 / h). Assuming that the solvent to be treated is supplied for 8 hours a day from the factory line, the adsorption time is 8h, the adsorption idle time is 16h, the adsorption process is 24h, the time in the water purge process is 10min, the desorption process The desorption time was 23.8 h, and the water purge + desorption process was combined for 24 h to make an adsorption / desorption cycle. When one adsorption tower was an adsorption process, the other adsorption tower performed the desorption process. At that time, the outlet average moisture concentration in the recovered organic solvent was 0.7% by weight or less.

  The recovered organic solvent purified by the solvent refining apparatus of this example has an average outlet water concentration of 0.7% by weight or less even when the adsorption / desorption cycle of the adsorption process → water purge process → desorption process is repeated. It was possible to maintain. Since the adsorption and desorption are continuously purified in two adsorption towers alternately, the performance can be stably and highly purified without degradation in performance. Moreover, it is possible to purify the organic solvent recovered from the solvent recovery processing apparatus actually operated in the factory with high efficiency.

[Example 5]
An adsorption tower of 1.5 mmφ and 90 mm thickness is packed with 15 g of adsorbent of a cation exchange resin (Na type, sulfonic acid group, Muromac DW2-1, manufactured by Muromachi Technos Co., Ltd.) having an average particle size of 1 mm. Assembling into the system flow of the 1 tank type solvent refining apparatus, ethyl acetate containing 3% by weight of water was introduced. As a result of confirming the time-dependent change of the outlet moisture concentration at that time, when SV = 20 (1 / h), the initial outlet moisture concentration was 0.1% by weight, and the moisture until the outlet moisture concentration reached 1% by weight. The adsorption amount (q *) was 0.6 (g / g-resin), indicating a good moisture adsorption amount.

Next, as a water purge step, water was introduced into the adsorption tower from the water purge introduction path. When the ethyl acetate concentration in the outlet water at that time is measured, when SV = 20 (1 / h), 95% or more of ethyl acetate adhering to the adsorbent can be removed with an amount of water four times the adsorbent volume. Good removal performance was shown.
Subsequently, air at 20 ° C. and 15 ° C. DP was used as a desorption gas in the desorption step, and the desorption SV was 20000 (1 / h). The adsorption time in the adsorption process was 1 h, the time in the water purge process was 10 min, the desorption time in the desorption process was 4 h, and the adsorption / desorption cycle was set. At that time, the average outlet water concentration in the ethyl acetate was 0.85% by weight at the beginning, but the outlet water concentration was 1% by weight and 1.2% by weight each time the second and third cycles were repeated. Rose.

The ethyl acetate purified by the solvent refining apparatus of this example will break through after 2 hours unless the desorption operation is performed, the outlet moisture concentration becomes 3% by weight, which is the same as the inlet moisture concentration, and the moisture removal function is lost. Stable purification was not possible.
Further, even if the adsorption / desorption cycle of the adsorption process → water purge process → desorption process is repeated, the desorption performance of the adsorbent in the desorption process is low, so that the outlet average moisture concentration in ethyl acetate is 0. Since the outlet average water concentration increased from 85% by weight and increased to 2% by weight, the outlet water concentration was significantly higher than that of the example.

  The solvent refining apparatus of the present invention is a refining apparatus that realizes continuous refining of the solvent, basically does not require replacement of the adsorbent, and can remove a large amount of water with high efficiency and stability. The adsorbent replacement work can be omitted without the need for cost reduction and stable removal of moisture. As a result, it can be used for the purification of solvents recovered from exhaust gas generated from a wide range of fields such as laboratories and factories using a solvent recovery processing apparatus, and it contributes greatly to the industry.

An example of a preferred embodiment of the present invention is a single column type solvent purification apparatus. The solvent purification apparatus of the adsorption tower 2 tower | column continuous adsorption / desorption system which is an example of the preferable one form of this invention. Solvent recovery processing equipment using activated carbon fiber.

Explanation of symbols

1: Adsorption tower
2: Organic solvent tank to be treated
3: Processed organic solvent introduction line
4: Damper
5: Damper
6: Purified organic solvent discharge line
7: Purified organic solvent tank
11: Water tank
12: Water pump
13: Damper
21: Compressor
22: Damper
23: Water or dry air introduction line
24: Damper
25: Damper
26: Water or desorption air discharge line
27: Damper
28: Return line
31: Adsorption tower
32: Damper
33: Damper
34: Damper
35: Damper
41: Gas to be treated
42: Fan
43: Adsorption tower
44: Activated carbon fiber element
45: Steam
46: Clean gas
47: Condenser
48: Separator
49: Recovery solvent

Claims (6)

  An adsorption process for allowing the adsorbent to adsorb moisture contained in the organic solvent by passing the organic solvent through the adsorbent packed in the adsorption tower; and passing an inert gas or air through the adsorbent. And a desorption step of desorbing moisture adsorbed on the adsorbent, wherein the adsorbent is at least one of ion exchange resin, activated alumina, molecular sieves, and silica gel.   2. The desorption gas introduction path for introducing the inert gas or air into the adsorbent, and the desorption gas introduction path having a unit capable of drying and / or heating the deactivation gas or air. Solvent refining equipment.   The solvent purifier according to claim 2, further comprising a water purge introduction path for introducing water into the adsorbent.   When at least two adsorption towers, one of which introduces the desorption gas from the desorption gas introduction path, the other towers continuously introduce the organic solvent from the treated organic solvent introduction path. The solvent purifier according to claim 1, wherein the organic solvent can be purified.   The solvent purifier according to any one of claims 1 to 4, wherein the adsorbent is an ion exchange resin, and is a cation exchange resin having at least one of a hydrogen ion form, a sodium form, and an alkanolamine form.   The solvent purification apparatus according to claim 5, wherein the cation exchange resin is granular or fibrous.

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