JP2010149040A - Organic solvent-containing gas treating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic solvent-containing gas treating system having an apparatus capable of stably removing acid component and moisture out of a large amount of collected organic solvents and capable of effectively utilizing drainage separated and discharged from the apparatus without discharging it to the environment such as rivers. <P>SOLUTION: The organic solvent-containing gas treating system includes: an organic solvent collecting system that introduces treated gas into an organic solvent collecting/treating apparatus 10 having an absorption tank 13 filled with absorbent materials 14, after performing absorption treatment on the organic solvents and discharging the treated gas where the organic solvent concentration is decreased to complete the absorption treatment, introduces steam into the absorption tank of the organic solvent collecting/separating apparatus and desorbs the organic solvent from the absorbent materials, and introduces the steam containing the organic solvent generated into a solvent separating apparatus 20 that condenses and separates the steam containing the organic solvent; and an acid component removing solvent-refining apparatus 23 that introduces the collected organic solvent separated by the organic solvent collecting/treating apparatus into a solvent refining apparatus 40 having an absorption tank filled with an acid component removing agent, and discharges the treated organic solvent where the concentration of the acid component in the organic solvent is decreased. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic solvent-containing gas treatment system that recovers an organic solvent from a gas to be treated containing an organic solvent, purifies the recovered solvent, and treats separated wastewater, and is particularly discharged from various factories and research facilities. The present invention relates to an organic solvent-containing gas treatment system used for purification of industrial exhaust gas containing an organic solvent.

  Conventionally, as an organic solvent recovery device in an organic solvent-containing gas processing system, an adsorption tank for adsorbing an organic solvent of a gas to be processed with activated carbon material, a gas supply means to be processed and a desorption gas supply means for each adsorption tank are provided. A switching means for switching between an adsorption processing apparatus for supplying a gas to be processed to the adsorption tank and a desorption processing state for supplying a desorption gas is provided. Moreover, granular activated carbon, activated carbon fiber, zeolite, silica gel, activated alumina or the like is used as the adsorbent for the organic solvent recovery apparatus. In particular, activated carbon fiber has an excellent function of adsorbing low-concentration organic gas, and has been used as an adsorbent for a long time.

  For example, Patent Documents 1 and 2 propose an apparatus in which activated carbon fibers are fixed to a support or are formed in a cylindrical shape by self-supporting and arranged in a vertical mold in a core material. Also, Patent Documents 3 to 5 propose similar adsorption / desorption devices. In any of these, steam is jetted onto a core material storing activated carbon fibers to desorb organic substances adsorbed on the activated carbon fibers. The desorbed organic solvent-containing water vapor is introduced into an organic solvent separator, and is condensed to separate the organic solvent and water to recover the organic solvent.

  The recovered organic solvent separated by the organic solvent separator is often mixed with moisture and acid components, and may not be industrially used as it is. In some cases, distillation is entrusted to a rectification manufacturer. As an organic solvent refining device, a distillation refining device that can obtain a high-purity organic solvent by heating and evaporating the organic solvent and fractionating the organic solvent and impurities using the difference in boiling point is widely used. However, since the distillation purification apparatus is a large apparatus, a large installation space is required, and both the 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 activated carbon, zeolite, ion exchange resin, molecular sieves, and activated alumina (for example, However, when refining a large amount of organic solvent, a large amount of adsorbent is required, and when the adsorbent is in a breakthrough state, the adsorbent must be replaced. The higher the cost, the higher the running cost. Therefore, it is an effective means at the laboratory level, but it is not satisfactory for purifying a large amount of organic solvent recovered from factories or research facilities.

  Moreover, since the wastewater separated by the organic solvent separation device contains an organic solvent, it cannot be discharged as it is to a river or the like, and therefore, a wastewater treatment device is provided for treatment. An effective method such as an aeration tank that volatilizes and removes the organic solvent in the wastewater has been developed as a wastewater treatment device (see, for example, Patent Document 10). However, it is necessary to finally discharge the wastewater to a river or the like. It was.

Japanese Patent Laid-Open No. 51-38278 Japanese Examined Patent Publication No. 64-11326 No. 7-2028 No. 7-2029 No. 7-2030 JP 2001-300206 A Japanese Patent No. 3832868 JP 2000-225316 A JP-A-5-220303 JP-A-2-169085

The present invention has been made against the background of the problems of the prior art, and realizes continuous purification of a recovered organic solvent containing an acid component, moisture, etc. separated from an organic solvent recovery device, and a large amount of recovered organic solvent Equipped with a device that can stably remove acid components and moisture from
An object of the present invention is to provide an organic solvent-containing gas treatment system that can effectively use waste water separated and discharged from an organic solvent recovery device without discharging it into an environment such as a river.

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. A gas to be treated containing an organic solvent is introduced into an organic solvent recovery treatment apparatus equipped with an adsorption tank filled with an adsorbent, and the treated gas having a reduced organic solvent concentration is obtained by adsorbing the organic solvent in the adsorption tank. After the discharge and the adsorption treatment in the adsorption tank are completed, steam is introduced into the adsorption tank of the organic solvent recovery treatment device, the organic solvent is desorbed from the adsorbent, thereby regenerating the adsorbent, and at the time of regeneration An organic solvent recovery system for separating and recovering the organic solvent by introducing it into a solvent separator for condensing and separating the generated organic solvent-containing water vapor;
The recovered organic solvent separated by the organic solvent recovery treatment device is introduced into an acid component removal solvent purification device having an adsorption tank filled with an acid component removal agent, and the recovered organic solvent is removed from the acid component removal solvent purification device. An organic solvent-containing gas treatment system equipped with an acid component removal solvent refining device that discharges the treated organic solvent in which the concentration of the acid component in the organic solvent has been reduced by adsorption treatment with an acid.

2. In the solvent refining equipment for acid component removal, the acid component remover is one of magnesium chloride, potassium chloride, calcium chloride, barium chloride, magnesium carbonate, potassium carbonate, calcium carbonate, barium carbonate, or a combination of two or more. 2. The organic solvent-containing gas treatment system as described in 1 above, wherein

3. An organic solvent recovery system;
A solvent refining device for removing an acid component from the recovered organic solvent recovered by the organic solvent recovery system;
3. The organic solvent-containing gas treatment system according to the above 1 or 2, comprising a water removal solvent purification device for removing water from the recovered organic solvent from which the acid component has been removed by the acid component removal solvent purification device.

4). A solvent purifier for removing moisture passes an adsorption process in which an organic solvent containing moisture is passed through the adsorbent to adsorb moisture onto the adsorbent, and adsorbs the adsorbent by passing dry air through the adsorbent. 4. The organic solvent-containing gas treatment system according to 3 above, wherein the organic solvent-containing gas treatment system has a purging step for removing the organic solvent adhering to the adsorbent by flowing water during the desorption step of desorbing the generated water. .

5. 5. The organic solvent-containing gas treatment system according to 3 or 4 above, comprising a line for introducing the organic solvent-containing purge water discharged in the purge step into the inlet of the aeration tank in the solvent purification apparatus for removing water.

6). Wastewater separated and discharged by the solvent separator in the organic solvent recovery system that separates and recovers the organic solvent is introduced into the cooling tower, cooling water is introduced from the cooling tower to the condenser in the solvent separator, and the used cooling water is supplied to the cooling tower. The organic solvent containing gas processing system in any one of said 1-5 provided with the line to return.

7). As a water treatment means to remove the organic solvent components in the wastewater discharged from the solvent separator in the organic solvent recovery system that separates and recovers the organic solvent, an aeration tank that volatilizes and removes the organic solvent in the wastewater and / or An adsorption process in which water containing an organic solvent is passed through the adsorption element to adsorb the organic solvent in the adsorption element, and a high-temperature heated gas is passed through the adsorption element to desorb the organic solvent adsorbed on the adsorption element. 6. The adsorption / desorption type water treatment apparatus that alternately performs the desorption step to be performed is provided before the waste water discharged from the solvent separation apparatus in the organic solvent recovery system for separating and recovering the organic solvent is introduced into the cooling tower. Organic solvent-containing gas treatment system.

8). 8. The water treatment means according to 7 above, wherein the first stage is an aeration tank and the second stage is an adsorption / desorption type water treatment apparatus, and includes a line for returning the organic solvent gas removed from the waste water by the water treatment means to the inlet of the organic solvent recovery apparatus. Organic solvent containing gas treatment system.

9. 9. The organic solvent-containing gas treatment system according to 7 or 8 above, further comprising a neutralization tank for adjusting the pH after the water treatment means.

The organic solvent-containing gas processing system according to the present invention introduces a recovered organic solvent containing an acid component and water separated from an organic solvent recovery processing device into a continuous purification device using an adsorbent, so that a large amount of The advantage that acid components and moisture can be stably removed from the recovered organic solvent,
By effectively treating the organic solvent-containing wastewater separated and discharged from the organic solvent recovery treatment device with the water treatment device, the advantage of removing the organic solvent in the wastewater,
The advantage that the organic solvent can be effectively recovered by returning the removed organic solvent to the organic solvent recovery processing device,
Furthermore, the wastewater separated and discharged from the organic solvent recovery treatment device or the wastewater treated by the water treatment device is introduced into the cooling tower to realize a system that does not discharge wastewater. There is an advantage that the cooling water required for the condenser of the solvent separator for condensing the solvent-containing water vapor can be produced from the waste water.

Two examples of embodiments of the present invention will be described.
First, a description will be given with reference to FIG. The gas to be treated 11 is introduced into the organic solvent recovery treatment apparatus 10 by the adsorption blower 12. The introduced gas 11 to be treated is sent to the adsorption tank 13, and when passing through the adsorbent 14, the organic solvent in the gas to be treated is adsorbed and removed and discharged from the treatment outlet 16 as clean air. On the other hand, the organic solvent-containing water vapor 17 containing the organic solvent desorbed from the adsorbent 14 by supplying the desorbing steam 15 to the adsorbent 14 is sent to the solvent separator 20, liquefied by the condenser 21, and separated waste water. 22 and recovered organic solvent 23. The separated recovered organic solvent 23 is introduced into an acid component removing solvent purifier 40. On the other hand, the separated drainage 22 is a system that is introduced into the aeration tank 31 and aerated, introduced into the neutralization tank 32, neutralized, and then introduced into the cooling tower 33.

  Next, FIG. 2 will be described. The gas to be treated 11 is introduced into the organic solvent recovery treatment apparatus 10 by the adsorption blower 12. The introduced gas 11 to be treated is sent to the adsorption tank 13, and when passing through the adsorbent 14, the organic solvent in the gas to be treated is adsorbed and removed and discharged from the treatment outlet 16 as clean air. On the other hand, the organic solvent-containing water vapor 17 containing the organic solvent desorbed from the adsorbent 14 by supplying the desorption steam 15 to the adsorbent 14 is sent to the solvent separator 20, liquefied by the condenser 21, and separated. The waste water 22 and the recovered organic solvent 23 are separated. The separated recovered organic solvent 23 is introduced into an acid component removing solvent refining apparatus 40 and introduced into a treated recovered organic solvent tank 51. The recovered organic solvent is introduced from the treated recovered organic solvent tank 51 into the moisture adsorption tower 52 filled with the adsorbent, and the adsorbent adsorbs and removes moisture in the recovered organic solvent, and is then introduced into the recovered organic solvent tank 53. On the other hand, water is introduced from the purge water tank 54 to the moisture adsorption tower 52 using the water pump 55, and the residual organic solvent adhering to the adsorbent in the moisture adsorption tower 52 is purged, and a purge water aeration tank It is introduced into the aeration tank 31 through the introduction line 58. Thereafter, dry air is introduced from the compressor 56 into the moisture adsorption tower 52, and moisture adsorbed on the adsorbent is desorbed. The used dry air at this time is introduced into the aeration tank 31 through the purge water aeration tank introduction line 58. Further, the separated waste water 22 containing the organic solvent separated by the solvent separation device 20 is introduced into the aeration tank 31 to volatilize and remove the organic solvent, and is an inlet of the organic solvent recovery processing device 10 through the return gas introduction line 34. Return to the gas 11 to be treated. Wastewater after treatment in the aeration tank 31 is introduced into an adsorption / desorption type organic solvent-containing water treatment device 60, introduced into the adsorbent 61, and adsorbed and removed, and the treated wastewater is introduced into the neutralization tank 32. It is introduced into the Wago Cooling Tower 33. The cooling water produced from the waste water in the cooling tower is supplied to the condenser 21 in the solvent separator 20. On the other hand, air is supplied by the purge air supply blower 64 to purge the water adhering to the adsorbent 61 after adsorption, and the water is returned to the inlet of the adsorbent 61 through the return water line 65. After the purge process, the organic solvent is desorbed with heated air in which the air supplied from the desorption gas supply blower 62 is heated by the desorption gas heater 63. The organic solvent-containing air volatilized in the aeration tank 31 and the organic solvent-containing air desorbed in the adsorption / desorption-type organic solvent-containing water treatment device 60 pass through the return gas line 66 to be treated gas 11 as an inlet of the organic solvent recovery treatment device 10. It is a system to return to.

  The adsorbent of the organic solvent recovery apparatus according to the present invention is not particularly limited, such as granular activated carbon, activated carbon fiber, zeolite, silica gel, etc., but activated carbon fiber is particularly preferable. This is because the activated carbon fiber in such an adsorbent has a higher adsorption speed than granular activated carbon and is excellent in the function of adsorbing low-concentration organic gas.

  The solvent purification apparatus for removing acid components according to the present invention is preferably an adsorption exchange filter unit type purification apparatus filled with an inexpensive adsorbent. The adsorbent is preferably one or a combination of two or more of magnesium chloride, potassium chloride, calcium chloride, barium chloride, magnesium carbonate, potassium carbonate, calcium carbonate, barium carbonate and the like. The shape of the adsorbent is not particularly limited, such as granular, powder, honeycomb, etc., but it is easy to mold and has a low pressure loss when flowing a liquid solvent, so that the adsorbent can be removed from the system. Granules with little outflow are preferred. The size of the particle shape is preferably 0.3 mm or more so that the adsorbent hardly flows out. For example, when granular calcium carbonate is used, there is a method of granulating powdered calcium carbonate, but it is also possible to use a crushed natural stone such as limestone or cold water stone in which the calcium carbonate component accounts for 90% or more. Inexpensive and effective.

  The acid components that can be removed in the solvent refining apparatus for removing acid components are strong acids such as hydrochloric acid, sulfuric acid, perchloric acid, weak acids such as nitric acid, acetic acid, formic acid, and carbonic acid. In consideration of the above, it is preferable to select an adsorbent suitable for the acid component. In order to remove acetic acid, it is preferable to select inexpensive calcium carbonate.

  As the solvent purification apparatus for removing water according to the present invention, a continuous adsorption / desorption method using an adsorbent is preferable. Compared to the one-pass adsorption exchange filter unit type, the life of the adsorbent is dramatically increased, and the running cost due to the exchange of the adsorbent can be greatly reduced. As the adsorbent, zeolite, silica gel or activated alumina may be used, but a cation exchange resin is preferably used. The cation exchange resin not only adsorbs organic solvents but can absorb only moisture, and its moisture retention is 2 to 20 times higher than other adsorbents, and is granular or fibrous. This is because the amount of filling into the adsorption tank can be increased, and the contact efficiency between the liquid organic solvent and the adsorbent is high, and moisture can be adsorbed efficiently.

  In an organic solvent refining device for removing moisture, adsorption is performed between an adsorption process in which an organic solvent is introduced into the adsorbent to adsorb moisture and a desorption process in which dry air is introduced into the adsorbent and moisture in the adsorbent is desorbed. It is preferable to add a purge step of purging the organic solvent adhering to the material with water. In other words, by removing the organic solvent adhering to the adsorbent in the purge process, not only can the adsorbent be easily dried in the subsequent desorption process, but also the adhering organic solvent can be recovered, which is efficient. It is.

  The operation of the adsorbent for the organic solvent refining apparatus for removing water preferably employs a system capable of continuous removal provided with two or more adsorption tanks, but the amount of water to be removed, the amount of organic solvent to be treated, etc. Considering this, intermittent operation 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 cooling tower according to the present invention is not particularly limited to an open type and a closed type, but it is preferable to select an optimal cooling tower according to the amount of drainage. In addition, the structure of the cooling tower when the open type is adopted is also the same, and it is preferable to select an optimal shape, square or round, depending on the amount of drainage. Furthermore, although it does not specifically limit regarding the use of the cooling water manufactured from the waste_water | drain with the cooling tower, It is more preferable to use it for the condenser in an organic solvent separation apparatus.

  The wastewater treatment device installed between the organic solvent recovery treatment device and the cooling tower according to the present invention is not particularly limited to an aeration type, an adsorption exchange filter unit type, an adsorption / desorption treatment type, and an activated sludge type, but an aeration type An adsorption / desorption type water treatment device is preferred. This is because, since the organic solvent is often contained at a high concentration, the adsorption exchange filter unit is frequently replaced, and the activated sludge type requires a large installation space.

  In the aeration type waste water treatment apparatus, it is preferable to heat the organic solvent to promote the volatilization of the organic solvent. At this time, by using a heat exchanger or the like, it is more economically preferable to use the latent heat or sensible heat of the organic solvent-containing water vapor desorbed from the organic solvent recovery treatment apparatus as a heat source for the waste water in the aeration tank.

  Examples of the adsorbent of the adsorption / desorption treatment type wastewater treatment equipment include granular, powder, fiber, and honeycomb activated carbon, zeolite, silica gel, activated alumina, and the like, and in particular, a continuous adsorption / desorption method using activated carbon fibers. A waste water treatment device is preferred. In other words, the activated carbon fiber has micropores on the surface and a fibrous structure, so the contact efficiency with water is high, and in particular, the adsorption rate of the organic solvent in water is increased, which is extremely high compared to other structures. This is because high removal efficiency can be exhibited, and even when water droplets on the surface of the adsorption element are removed by gas flow in a purge process introduced for high-efficiency processing, water droplets can be easily removed.

  In the waste water treatment apparatus, it is preferable to provide a neutralization tank downstream of the aeration type and / or adsorption / desorption type water treatment apparatus. This is because the pH of the waste water discharged from the aeration type and / or the adsorption / desorption type water treatment device is acidic, so that the corrosion of the cooling tower and piping can be suppressed by neutralization.

  In the wastewater treatment apparatus, it is preferable to return the organic solvent-containing air that has been volatilized or desorbed through the return gas line to the inlet of the organic solvent recovery treatment apparatus. This is because the organic solvent can be further recovered from the generated organic solvent-containing air, which is efficient.

  In the organic solvent-containing gas treatment system according to the present invention, the organic solvents that can be treated are ethyl acetate, methyl acetate, butyl acetate, methyl ethyl ketone, methyl butyl ketone, heptanone, acetone, toluene, xylene, benzene, PGMEA, PGME, methanol, ethanol. , Propanol, chloroform, methylene chloride, carbon tetrachloride and the like are not particularly limited, and a mixture thereof is no exception.

  In the air exhausted from the cooling tower in the organic solvent-containing gas treatment system according to the present invention, when a trace amount of organic solvent is contained, the organic matter in the air exhausted from the cooling tower using the organic solvent-containing gas concentration treatment device is used. It is preferable to concentrate the solvent and return it to the inlet of the organic solvent recovery processor. FIG. 3 shows the principle of the organic solvent-containing gas concentration treatment apparatus. In the drawing, an organic solvent-containing gas concentration treatment device 90 for adsorbing an organic solvent in a gas containing a large amount of air and a low concentration volatile organic compound (VOC) is a cylindrical shape that can rotate around a rotation center axis 96. The case 91 has an adsorbent 95 made of a honeycomb structure (with the communication path oriented in the central axis direction) for adsorbing VOC in the case 91, and forms a cylindrical adsorbent as a whole. ing. For the adsorbent 95, activated carbon fiber, zeolite paper, or the like is appropriately selected according to the components of the VOC-containing gas. An adsorbing portion 93 and a desorbing portion 97 are partitioned on a moving path along which the cylindrical adsorbing body rotates, and an adsorbent 95 passes through the adsorbing portion 93 and the desorbing portion 97 alternately. In the adsorbing section 93, for example, clean air purified by the VOC-containing gas supply pipe 92 for introducing the VOC-containing gas generated in the factory and the adsorbent 95 of the organic solvent-containing gas concentration treatment apparatus 90 is sent to the factory. A purified air delivery pipe 94 is provided for delivery. In addition, the desorption part 97 is provided with a desorption air supply pipe 98 for blowing high-temperature dry air at 180 ° C., that is, desorption heating air, to the adsorbent 95 that has adsorbed VOC. Is set to be about 1/2 to 1/50 of the volume of the VOC-containing gas, so that the desorbed gas is concentrated.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
The evaluation was performed by the following method.

(Ethyl acetate, acetic acid, ethanol, methylene chloride solvent concentration evaluation)
The concentrations at the inlet and outlet were analyzed and measured by gas chromatography.

(Evaluation of water concentration in solvent)
The water concentration of the recovered organic solvent was analyzed using a Karl Fischer-water concentration meter.

(Exclusion rate)
Removal rate (%) = (device inlet gas concentration−device outlet gas concentration) / device inlet gas concentration × 100

[Example 1]
Using the organic solvent-containing gas treatment system shown in FIG. 2, a gas to be treated 11 containing 2000 ppm of ethyl acetate was introduced into the organic solvent recovery treatment apparatus 10. At that time, the air flow is blown from the adsorption blower 12 to the adsorption tank 13 at an air flow rate of 100 Nm ³ / min, and the adsorption tank 13 serves as an adsorbent 14 with an average pore diameter of 17.4 mm, a BET specific surface area of 1650 m ² / g, and a total pore volume of 0.66 cm. ³ / g of activated carbon fiber was used, adsorption was performed for 9 minutes, and clean air was discharged. The ethyl acetate concentration of the clean air at that time was 20 ppm or less, and the treatment was performed with a removal rate of 99%. Thereafter, the air blown to the adsorption tank 13 was blocked with an automatic damper, and then the desorption steam 15 was jetted onto the activated carbon fiber of the adsorption tank. Simultaneously with this treatment, the automatic damper of another adsorption tank was opened, and this time the adsorption process of ethyl acetate gas was performed in this adsorption tank. This adsorption and desorption operation was repeated.

  The organic solvent-containing water vapor 17 obtained from the organic solvent recovery treatment device 10 is sent to the solvent separation device 20 and cooled by the condenser 21, and the recovered organic solvent 23 mainly composed of ethyl acetate and the separated waste water 22 containing a small amount of ethyl acetate are obtained. Obtained. The ethyl acetate concentration in the recovered organic solvent is 96.8% by weight, the water concentration is 3.1% by weight, the ethanol concentration is 400 ppm, and the acetic acid concentration is 600 ppm. The ethyl acetate concentration in the separated wastewater is 40000 ppm, the acetic acid concentration is 2000 ppm, The ethanol concentration was 2000 ppm, and the amount of water was 310 kg / hr.

  The recovered organic solvent was introduced into an acid component removing solvent refining apparatus 40 filled with 1000 g of an adsorbent of cold water stone (manufactured by Niimi Chemical Industry Co., Ltd.) having an average particle size of 1.5 mm. As a result of confirming the time-dependent change of the outlet acetic acid concentration at that time, the outlet acetic acid concentration was 60 ppm or less and the outlet water concentration was 3.1 wt% when SV = 10 (1 / h). Moisture filled with 30 weight kg 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 0.7 mm with the recovered organic solvent from which acetic acid has been removed. It was introduced into the adsorption tower 52. As a result of confirming the time-dependent change in the outlet moisture concentration at that time, 360 kg / day of a recovered organic solvent having a moisture concentration of 0.5% by weight or less was obtained when SV = 5 (1 / h). Next, as a water purge step, the concentration of ethyl acetate in the outlet water when the purge water was introduced into the moisture adsorption tower 52 from the purge water tank 54 using the water pump 55 was measured. As a result, when SV = 20 (1 / h), it was possible to remove 95% or more of ethyl acetate adhering to the adsorbent with an amount of water 4 times the volume of the adsorbent. At this time, the purge water containing ethyl acetate was introduced into the solvent separator 20. Subsequently, dry air at 20 ° C. and −10 ° C. DP was used as the desorption gas in the desorption step, and the desorption SV was 2000 (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 23 h, and the adsorption / desorption cycle was established.

The separated waste water 22 was introduced into the aeration tank 31. The waste water in the aeration tank was heated from 40 ° C. to 70 ° C. and aerated. The concentration of the wastewater treated in the aeration tank 31 was 40 ppm or less of ethyl acetate, and could be treated at a removal rate of 99% or more. Moreover, it was able to be reduced to a concentration of 100 ppm acetic acid and 50 ppm ethanol. Further, the solvent gas volatilized at this time was returned to the gas 11 to be processed which is the inlet of the organic solvent recovery processing apparatus 10 through the return gas introduction line 34. Next, the wastewater introduced into the aeration tank 31 was introduced into the adsorption / desorption type organic solvent-containing water treatment device 60, and the adsorbent 61 adsorbed the solvent in the wastewater. The concentration of the waste water at this time was 3 ppm or less of ethyl acetate, 5 ppm or less of acetic acid, and 3 ppm or less of ethanol. The purged and heat-desorbed solvent-containing gas was returned to the gas to be processed 11 which is the inlet of the organic solvent recovery processing apparatus 10 through the return gas line 66. Thereafter, the treated waste water was introduced into the neutralization tank 32 and the pH was neutralized to 7. The BOD of the waste water at this time was 30 mg / L or less, and the COD was 10 mg / L or less. Thereafter, waste water was introduced into the cooling tower 33, cooling water was produced from the waste water, and the produced cooling water was introduced into the condenser 21. At this time, 28% of 280 kg / hr in the supplementary cooling water 1 m ³ / hr out of the cooling water 19 m ³ / hr necessary for the condenser 21 could be supplied from the cooling tower.

  The organic solvent-containing gas treatment system of this example was capable of treating with an efficiency of 90 to 99% for both the removal rate of the organic solvent recovery device, the performance of the solvent purification device, and the water treatment device removal rate even after 100 hours. Since adsorption and desorption are performed continuously, processing is stable and highly efficient with no performance degradation. Furthermore, since the wastewater can be used as cooling water, not only is it economically efficient, but also the advantage of not discharging the wastewater into the environment can be added.

[Example 2]
Using the organic solvent-containing gas treatment system shown in FIG. 1, a gas to be treated 11 containing 2000 ppm of methylene chloride and 5 ppm of acetic acid at 30 ° C. was introduced into the organic solvent recovery treatment apparatus 10. At that time, the air flow was blown from the adsorption blower 12 to the adsorption tank 13 at an air flow of 100 Nm ³ / min, and the average fine pore diameter of 17.4 mm, the BET specific surface area of 1650 m ² / g, and the total pore volume of 0.66 cm ³ as the adsorbent 14 in the adsorption tank. / G of activated carbon fiber 14 was used for adsorption for 9 minutes, and clean air was discharged. The methylene chloride concentration of the clean air at that time was 20 ppm or less, and the treatment was performed with a removal rate of 99% or more. Thereafter, the air blown to the adsorption tank 13 was blocked with an automatic damper, and then the desorption steam 15 was jetted onto the activated carbon fiber of the adsorption tank. Simultaneously with this treatment, the automatic damper of another adsorption tank was opened, and this time the adsorption treatment of methylene chloride gas was performed in this adsorption tank. This adsorption and desorption operation was repeated.

  The organic solvent-containing water vapor 17 obtained from the organic solvent recovery treatment device 10 is sent to the solvent separation device 20 and cooled by the condenser 21, and the recovered organic solvent 23 mainly composed of methylene chloride and the separated waste water 22 containing a small amount of methylene chloride are obtained. Obtained. The methylene chloride concentration in the recovered organic solvent was 99.5% by weight, and the acetic acid concentration was 2500 ppm.

  The recovered organic solvent was introduced into an acid component removing solvent refining apparatus 40 filled with 1000 g of an adsorbent of cold water stone (manufactured by Niimi Chemical Industry Co., Ltd.) having an average particle size of 1.5 mm. As a result of confirming the change with time in the outlet acetic acid concentration, the outlet acetic acid concentration was 250 ppm or less when SV = 10 (1 / h).

  The organic solvent-containing gas treatment system of this example was capable of treating with an efficiency of 90 to 99% in both the removal rate of the organic solvent recovery device and the performance of the solvent purification device even after 100 hours.

  The organic solvent-containing gas treatment system of the present invention includes a simple and highly efficient purification of an organic solvent recovered from an organic solvent recovery treatment device, continuous purification of discharged separated waste water, and a non-drainage system by cooling the waste water. It was realized. Because it is a processing device that can remove large amounts of harmful organic substances with high efficiency and stability, it can reduce costs without the need for additional equipment, and can stably remove harmful substances, especially in a wide range of fields such as laboratories and factories. It is a great place to contribute to the industry.

It is an organic-solvent containing gas processing system which is an example of the preferable form of this invention. It is an organic-solvent containing gas processing system which is an example of the preferable form of this invention. It is an example of the organic solvent concentration processing system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Organic solvent collection | recovery processing apparatus 11 Gas to be processed 12 Adsorption fan 13 Adsorption tank 14 Adsorbent (activated carbon fiber)
DESCRIPTION OF SYMBOLS 15 Desorption steam 16 Process outlet 17 Organic solvent containing water vapor | steam 20 Solvent separation apparatus 21 Condenser 22 Separation water 23 Collect | recovered organic solvent 31 Aeration tank 32 Neutralization tank 33 Cooling tower 34 Return gas introduction line 35 Condenser introduction line 36 Condenser discharge line 40 Acid component Removal solvent refining equipment 50 Water removal adsorption / desorption type solvent refining equipment 51 Organic recovery solvent tank to be treated 52 Water adsorption tower 53 Recovered organic solvent tank 54 Purge water tank 55 Water pump 56 Compressor 57 Return line 58 Introduction of purge water aeration tank Line 60 Adsorption / desorption type organic solvent-containing water treatment device 61 Adsorbent (activated carbon fiber)
62 Desorption gas supply blower 63 Desorption gas heater 64 Purge air supply blower 65 Return water line 66 Return gas line 90 Organic solvent-containing gas concentration treatment device 91 Rotating cylindrical case 92 VOC-containing gas supply pipe 93 Adsorption part 94 Purification Air delivery pipe 95 Adsorbent 96 Rotation center shaft 97 Desorption part 98 Desorption air supply pipe

Claims (9)

A gas to be treated containing an organic solvent is introduced into an organic solvent recovery treatment apparatus equipped with an adsorption tank filled with an adsorbent, and the treated gas having a reduced organic solvent concentration is obtained by adsorbing the organic solvent in the adsorption tank. After the discharge and the adsorption treatment in the adsorption tank are completed, steam is introduced into the adsorption tank of the organic solvent recovery treatment device, the organic solvent is desorbed from the adsorbent, thereby regenerating the adsorbent, and at the time of regeneration An organic solvent recovery system for separating and recovering the organic solvent by introducing it into a solvent separator for condensing and separating the generated organic solvent-containing water vapor;
The recovered organic solvent separated by the organic solvent recovery treatment device is introduced into an acid component removal solvent purification device having an adsorption tank filled with an acid component removal agent, and the recovered organic solvent is removed from the acid component removal solvent purification device. An organic solvent-containing gas treatment system equipped with an acid component removal solvent refining device that discharges the treated organic solvent in which the concentration of the acid component in the organic solvent has been reduced by adsorption treatment with an acid.   In the solvent refining equipment for acid component removal, the acid component remover is one of magnesium chloride, potassium chloride, calcium chloride, barium chloride, magnesium carbonate, potassium carbonate, calcium carbonate, barium carbonate, or a combination of two or more. The organic-solvent containing gas processing system of Claim 1 comprised by the thing. An organic solvent recovery system;
A solvent refining device for removing an acid component from the recovered organic solvent recovered by the organic solvent recovery system;
The organic solvent-containing gas treatment system according to claim 1 or 2, further comprising a water removal solvent purification device that removes water from the recovered organic solvent from which the acid component has been removed by the acid component removal solvent purification device.   A solvent purifier for removing moisture passes an adsorption process in which an organic solvent containing moisture is passed through the adsorbent to adsorb moisture onto the adsorbent, and adsorbs the adsorbent by passing dry air through the adsorbent. The organic solvent-containing gas treatment according to claim 3, wherein the organic solvent-containing gas treatment device has a purging step for removing the organic solvent adhering to the adsorbent by flowing water during the desorption step of desorbing the dehydrated water. system.   5. The organic solvent-containing gas processing system according to claim 3, further comprising a line for introducing the organic solvent-containing purge water discharged in the purge step into an inlet of the aeration tank in the solvent purification apparatus for removing water.   Wastewater separated and discharged by the solvent separator in the organic solvent recovery system that separates and recovers the organic solvent is introduced into the cooling tower, cooling water is introduced from the cooling tower to the condenser in the solvent separator, and the used cooling water is supplied to the cooling tower. The organic solvent containing gas processing system in any one of Claims 1-5 provided with the return line.   As a water treatment means to remove the organic solvent components in the wastewater discharged from the solvent separator in the organic solvent recovery system that separates and recovers the organic solvent, an aeration tank that volatilizes and removes the organic solvent in the wastewater and / or An adsorption process in which water containing an organic solvent is passed through the adsorption element to adsorb the organic solvent in the adsorption element, and a high-temperature heated gas is passed through the adsorption element to desorb the organic solvent adsorbed on the adsorption element. 7. The adsorption / desorption type water treatment device that alternately performs the desorption step is provided before the waste water discharged from the solvent separation device in the organic solvent recovery system for separating and recovering the organic solvent is introduced into the cooling tower. Organic solvent containing gas treatment system.   The water treatment means comprises an aeration tank at the front stage and an adsorption / desorption type water treatment apparatus at the rear stage, and a line for returning the organic solvent gas removed from the waste water by the water treatment means to the inlet of the organic solvent recovery apparatus. The organic solvent containing gas processing system of description.   The organic solvent-containing gas treatment system according to claim 7 or 8, further comprising a neutralization tank for adjusting the pH after the water treatment means.

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