JP2011092870A - Organic solvent recovery system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic solvent recovery system which can recover an organic solvent from a gas to be treated at high concentrations and in good yield while suppressing the generation of an acid. <P>SOLUTION: The organic solvent recovery system 1A recovers the organic solvent from the gas to be treated containing the organic solvent generating the acid by reacting with water. The system includes an adsorption-desorption treatment apparatus 100, a membrane separator 210, and a condensation-recovery apparatus 300. The adsorption-desorption treatment apparatus 100 contains an adsorbent 111, 121 which can sorb and desorb the organic solvent contained in the gas to be treated and discharges a treated gas and a desorption gas by treating the gas to be treated. The membrane separator 210 discharges the desorption gas discharged from the adsorption-desorption treatment apparatus 100 separating into a separation gas containing the organic solvent at high concentrations and vapor. The condensation-recovery apparatus 300 condenses the separation gas discharged from the membrane separator 210 by cooling and recovers it as a recovery liquid containing the organic solvent at high concentration. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an organic solvent recovery system that recovers an organic solvent from a gas to be processed, and more particularly to an organic solvent recovery system that separates and recovers an organic solvent that generates an acid by reacting with water from the gas to be processed.

  Conventionally, there has been known an organic solvent recovery system that removes the organic solvent from the gas to be processed containing the organic solvent, purifies and discharges the gas to be processed, and concentrates and recovers the removed organic solvent to a high concentration. ing. This type of organic solvent recovery system generally contains a high-concentration organic solvent by bringing the gas to be treated into contact with the adsorbent material to adsorb the organic solvent, and blowing high-temperature heating gas onto it to desorb the organic solvent. A desorption gas containing a high concentration organic solvent discharged from the adsorption / desorption treatment device is condensed and separated in a separation tank, and separated into a high concentration. In combination with a condensing / recovering device that recovers a liquid containing a high concentration of the organic solvent as a recovered liquid (for example, Japanese Utility Model Publication No. 7-2028). No. (Patent Document 1), Japanese Utility Model Publication No. 7-2029 (Patent Document 2), Japanese Utility Model Publication No. 7-2030 (Patent Document 3), etc.).

  In addition, for the purpose of further increasing the yield of the organic solvent to be recovered, an organic material having a structure in which a membrane separation device based on the pervaporation separation method is further added to the downstream side of the condensation recovery device of the conventional organic solvent recovery system described above. A solvent recovery system has been proposed (see JP 2009-66530 A (Patent Document 4)). The organic solvent recovery system disclosed in Patent Document 4 further introduces a liquid containing a high concentration organic solvent recovered by a condensation recovery device into a membrane separation device based on a pervaporation separation method. In the above, a liquid having a higher concentration can be obtained by further separating and removing water from the liquid containing the high-concentration organic solvent. Further, the organic solvent recovery system is configured to further increase the yield of the organic solvent by returning the permeate mainly containing a large amount of water separated by the membrane separation device to the separation tank of the condensation recovery device. ing.

Japanese Utility Model Publication No. 7-2028 Japanese Utility Model Publication No. 7-2029 Japanese Utility Model Publication No. 7-2030 JP 2009-66530 A

  By the way, the recovered liquid containing a high concentration organic solvent is preferably reused after recovery from the viewpoints of economy and environment. However, when the organic solvent contained in the gas to be treated is an acetate ester or a basic compound, the organic solvent is included in the steam contained in the gas to be treated or the heating gas introduced in the adsorption / desorption treatment apparatus described above. It is known that an acid is generated by reacting with water vapor or water after condensation of the water vapor. For example, when acetic acid ester is contained in the gas to be treated, it is known that a part of the acetic acid ester is decomposed to generate acetic acid due to hydrolysis reaction.

  For this reason, in the conventional organic solvent recovery system, the recovered liquid may contain acid at a certain concentration, which has been a problem for reuse. Therefore, in the organic solvent recovery system that recovers the organic solvent from the gas to be treated that contains the organic solvent that generates acid by reacting with water, take measures to suppress the generation of acid as much as possible. Is required.

  Therefore, the present invention has been made to solve the above-described problems, and when an organic solvent is recovered from a gas to be treated containing an organic solvent that generates an acid by reacting with water, an acid is generated. An object of the present invention is to provide an organic solvent recovery system capable of recovering an organic solvent at a high concentration and a high yield while suppressing the above.

  An organic solvent recovery system according to the present invention recovers an organic solvent from a gas to be treated containing an organic solvent that generates an acid by reacting with water, and includes an adsorption / desorption treatment device, a membrane separation device, And a condensing recovery device. The adsorption / desorption treatment apparatus includes an adsorption element that adsorbs an organic solvent by bringing a gas to be treated into contact with the gas, and desorbs the adsorbed organic solvent by bringing a heated gas into contact with the gas to be treated. The organic solvent is adsorbed on the adsorption element and discharged as a processing gas, and the heated gas is supplied to the adsorption element to desorb the organic solvent from the adsorption element to obtain a desorption gas containing the organic solvent. To be discharged. The membrane separation apparatus includes a separation membrane that selectively permeates and separates water vapor contained in the desorption gas by bringing the desorption gas into contact with the desorption gas, and separates the desorption gas discharged from the adsorption / desorption treatment apparatus. By supplying to a membrane, it is separated into a separation gas containing an organic solvent and water vapor and discharged. And the said condensation collection apparatus is condensed by cooling the separation gas discharged | emitted from the said membrane separator, and collect | recovers it as a collection | recovery liquid which contains an organic solvent in high concentration.

  In the organic solvent recovery system according to the present invention, the adsorbing element is preferably an activated carbon fiber.

  In the organic solvent recovery system according to the present invention, the heating gas is preferably water vapor.

  In the organic solvent recovery system according to the present invention, the separation membrane is preferably a carbon membrane.

  In the organic solvent recovery system according to the present invention, the separation membrane preferably has a hollow fiber structure.

  The organic solvent recovery system according to the present invention is particularly preferably used when the gas to be treated contains at least one of acetate ester and basic compound as the organic solvent.

  According to the present invention, when recovering an organic solvent from a gas to be treated containing an organic solvent that generates an acid by reacting with water, the organic solvent is highly concentrated and has a high yield while suppressing the generation of the acid. It can be set as the organic solvent collection | recovery system which can be collect | recovered by.

It is a system configuration figure of an organic solvent recovery system in an embodiment of the invention. It is a schematic cross section of the membrane separator of the organic solvent collection | recovery system in embodiment of this invention. It is a system block diagram of the organic solvent collection | recovery system which concerns on a comparative example. It is a table | surface which shows the result of a verification test.

  Hereinafter, an embodiment 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 description thereof will not be repeated.

  FIG. 1 is a system configuration diagram of an organic solvent recovery system according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the membrane separation apparatus shown in FIG. First, with reference to these FIG. 1 and FIG. 2, the structure of the organic solvent collection | recovery system in this Embodiment is demonstrated.

  As shown in FIG. 1, the organic solvent recovery system 1A in the present embodiment includes an adsorption / desorption processing device 100, a separation device 200 including a membrane separation device 210, and a condensation recovery device 300.

  The adsorption / desorption treatment apparatus 100 includes a first treatment tank 110 and a second treatment tank 120 in which adsorbents 111 and 121 as adsorption elements are accommodated, respectively. The adsorbents 111 and 121 adsorb the organic solvent contained in the gas to be processed by contacting the gas to be processed. Therefore, in the adsorption / desorption processing apparatus 100, the organic solvent is adsorbed by the adsorbents 111 and 121 by supplying the gas to be treated to the adsorbents 111 and 121, whereby the gas to be treated is cleaned and discharged as the process gas. Will be. The adsorbents 111 and 121 desorb the adsorbed organic solvent by bringing water vapor as a heating gas into contact therewith. Therefore, in the adsorption / desorption processing apparatus 100, by supplying water vapor to the adsorbents 111 and 121, the organic solvent is desorbed from the adsorbents 111 and 121, whereby the water vapor is discharged as a desorption gas containing the organic solvent. become. Note that as the heated gas introduced into the adsorption / desorption treatment apparatus 100 for desorption of the organic solvent, a high-temperature inert gas or the like can be used in addition to water vapor.

  Piping lines L1, L2, L3, and L4 are connected to the first processing tank 110 and the second processing tank 120, respectively. The piping line L1 is a piping line for supplying a gas to be processed containing an organic solvent to the first processing tank 110 and the second processing tank 120, and the first processing tank 110 and the second processing tank by valves V101 and V102. The connection / disconnection state for 120 is switched. The piping line L2 is a piping line for supplying water vapor to the first processing tank 110 and the second processing tank 120, and is connected / disconnected to the first processing tank 110 and the second processing tank 120 by valves V103 and V104. Is switched. The piping line L3 is a piping for discharging the processing gas from the first processing tank 110 and the second processing tank 120, and is connected / disconnected to the first processing tank 110 and the second processing tank 120 by valves V105 and V106. Is switched. The piping line L4 is a piping line for discharging desorption gas from the first processing tank 110 and the second processing tank 120, and is connected / disconnected to the first processing tank 110 and the second processing tank 120 by valves V101 and V102. The state is switched.

  The first treatment tank 110 and the second treatment tank 120 function alternately as an adsorption tank and a desorption tank by operating the above-described opening and closing of the valves V101 to V106. Specifically, the first treatment tank 110 is adsorbed. When functioning as a tank, the second processing tank 120 functions as a desorption tank, and when the first processing tank 110 functions as a desorption tank, the second processing tank 120 functions as an adsorption tank. . That is, the adsorption / desorption processing apparatus 100 according to the present embodiment is configured such that the adsorption tank and the desorption tank are alternately switched over time. The piping line L1 is connected to a tank functioning as an adsorption tank among the first processing tank 110 and the second processing tank 120 and supplies a gas to be processed to the adsorption tank. Among the 1 treatment tank 110 and the 2nd treatment tank 120, it connects with the tank which is functioning as a desorption tank, and supplies water vapor | steam to the said desorption tank. The piping line L3 is connected to a tank functioning as an adsorption tank among the first processing tank 110 and the second processing tank 120 and discharges the processing gas from the adsorption tank. The piping line L4 is connected to the first processing tank 110 and the second processing tank 120. The processing tank 110 and the second processing tank 120 are connected to a tank functioning as a desorption tank and discharge the desorption gas.

  The adsorbents 111 and 121 are made of a member containing at least one of activated carbon, activated carbon fiber, and zeolite. Preferably, the adsorbents 111 and 121 are activated carbon or zeolite in the form of particles, granules or honeycombs, but more preferably activated carbon fibers. Since the activated carbon fiber has a fibrous structure having micropores on the surface, the activated carbon fiber has high contact efficiency with gas and is a member that can realize high adsorption efficiency as compared with other adsorption elements.

  The separation device 200 includes a membrane separation device 210 and a capacitor 220. The membrane separation device 210 is a device for selectively separating water vapor contained in the desorption gas from the desorption gas based on a so-called vapor permeation separation method (gas permeation separation method), and the capacitor 220 includes a membrane separation device. This is an apparatus for condensing the water vapor separated at 210 using cooling water or the like and discharging it as separated water.

  The membrane separation device 210 is connected to the piping lines L4, L5, and L7, and the capacitor 220 is connected to the piping lines L5 and L6, respectively. The piping line L4 is a piping line for supplying the desorption gas discharged from the adsorption / desorption processing device 100 described above to the membrane separation device 210, and the piping line L5 is separated and discharged by the membrane separation device 210. This is a piping line for supplying water vapor to the capacitor 220. The piping line L6 is a piping line for discharging the separated water obtained by condensing in the condenser 220 from the condenser 220, and the piping line L7 is a separation line separated and discharged by the membrane separation device 210. It is a piping line for discharging from the membrane separation device 210. The membrane separation device 210 may be constituted by a single group as shown in the figure, but can also be constituted by arranging a plurality of groups in parallel or in series. Furthermore, the separation gas discharged from the membrane separation device 210 may be returned to the membrane separation device 210 as a desorption gas and circulated for processing. By comprising in this way, it becomes possible to raise the yield of an organic solvent.

  As shown in FIG. 2, the membrane separation device 210 is connected so as to communicate with a shell 211 as an outer shell, an inner hollow separation membrane 212 accommodated in the shell 211, and an inner hollow of the separation membrane 212. The suction pipe 214 is mainly provided. Here, the separation membrane 212 is a membrane that selectively permeates water vapor contained in the desorption gas by contacting the desorption gas and separates it from other components contained in the desorption gas.

  The shell 211 is connected to the piping line L4 so that the desorption gas discharged from the adsorption / desorption processing device 100 is introduced into the inside of the shell 211, and the shell 211 is connected to the piping line L7. And a desorption port 216 for deriving the desorption gas after being ventilated from the shell 211 as a separation gas. One end of the separation membrane 212 is supported by the support member 213 a and the other end is supported by the support member 213 b and connected to the suction pipe 214. The suction pipe 214 is connected to a vacuum pump and capacitor 220 (not shown) by being connected to the piping line L5.

  Here, as the separation membrane 212, for example, various inorganic membranes and polymer membranes can be used, and a carbon membrane is particularly preferably used. This is because the desorption gas is a high-temperature gas and there is a possibility that the desorption gas contains a small amount of acid. By using a carbon film excellent in heat resistance, acid resistance, etc., the film This is because the life of the separation device 210 is increased.

  Even when a carbon membrane is used as the separation membrane 212, an acid may be generated by reaction with moisture in the membrane separation device 210 due to the metal contained in the carbon membrane. Therefore, it is preferable to suppress the generation of acid by appropriately adjusting the metal species and amount in the carbon film. Specifically, by selection of raw materials and adjustment of carbon film manufacturing conditions, F, P, S, Cl, K, Ca, Cr, Fe, Zn, Na, Mg, Cu, Co, Mn, Ni, etc. It is preferable to suppress each content to 500 ppm or less. Furthermore, it is also possible to reduce the amount of metal in the carbon film by washing the metal in the carbon film with an inorganic acid such as hydrochloric acid, for example, during the manufacturing process or post-treatment of the carbon film.

  The separation membrane 212 preferably has a hollow fiber structure. This makes it possible to increase the surface area per unit volume of the separation membrane by using the separation membrane 212 having a hollow fiber structure as compared with the case of using a separation membrane having another tube structure or the like. This is because the separation performance of the membrane separation device 210 can be increased. As a result, the membrane separation device 210 can be reduced in size, cost, and energy saving.

  Examples of the raw material for the carbon membrane having a hollow fiber structure include acrylic resins, polyimide resins, cellulose resins, polyphenylene oxide resins, polyfurfuryl alcohol, and phenol resins, but the raw materials are particularly limited. It is not a thing.

  The above-mentioned carbon membrane having a hollow fiber structure is obtained by processing the above-mentioned resin raw material or the like into a hollow shape and further heat-treating it in an inert atmosphere. The heat treatment temperature is equal to or higher than the thermal decomposition start temperature of the resin, and is generally 250 ° C. or higher. Since the heat treatment temperature in the inert atmosphere is directly related to the performance of membrane separation, an optimum temperature can be selected. However, if the temperature is too high, the pores of the carbon film are blocked by heat shrinkage, so the upper limit is desirably up to about 1300 ° C.

  In addition, before heat treatment in an inert atmosphere, heat treatment in air (also referred to as flame resistance, infusibilization, or thermal stabilization) or a flame retardant can be imparted to the resin. Further, after heat treatment in an inert atmosphere, chemical treatment or surface treatment such as heat treatment may be added. The carbon film is composed of elements such as carbon, hydrogen, oxygen, nitrogen, sulfur, and the above-described metal components, the main component is carbon, and the content is 60% or more. The upper limit of the carbon content is not particularly limited, but about 99.9% is a practical upper limit.

  The condensation recovery apparatus 300 includes a condenser 310 and a recovery tank 320. The condenser 310 is an apparatus for condensing the liquefied gas using cooling water or the like, and the recovery tank 320 is a liquid containing a high concentration organic solvent obtained by being condensed in the condenser 310. It is a tank for storing as a recovered liquid.

  The capacitor 310 is connected to the piping lines L7 and L8, respectively, and the recovery tank 320 is connected to the piping lines L8 and L9, respectively. The piping line L7 is a piping line for supplying the separation gas discharged from the membrane separation device 210 to the condenser 310, and the piping line L8 collects the recovered liquid obtained by being condensed by the condenser 310. This is a piping line for supplying to the tank 320. The piping line L9 is a piping line for discharging the recovered liquid stored in the recovery tank 320 to the outside.

  Next, the details of the processing performed in the organic solvent recovery system 1A in the present embodiment will be described with reference to FIG. The following description is based on the state in which the first treatment tank 110 of the adsorption / desorption treatment apparatus 100 functions as an adsorption tank and the second treatment tank 120 functions as a desorption tank. The same process is also performed when the desorption tank is replaced.

  As shown in FIG. 1, the gas to be treated containing an acetate ester or a basic compound is introduced into the adsorption / desorption treatment apparatus 100 via a piping line L1. The introduced gas to be treated is sent to the first treatment tank 110 and comes into contact with the adsorbent 111, and the organic solvent contained in the gas to be treated is adsorbed by the adsorbent 111. The gas after the organic solvent is adsorbed by the adsorbent 111 is introduced into the piping line L3 and discharged from the adsorption / desorption processing apparatus 100 as a processing gas.

  On the other hand, water vapor is introduced into the adsorption / desorption treatment apparatus 100 via the piping line L2 in parallel with the introduction of the gas to be treated. The introduced water vapor is sent to the second treatment tank 120 and comes into contact with the adsorbent 121 to desorb the organic solvent adsorbed on the adsorbent 121. The water vapor containing the organic solvent desorbed from the adsorbent 121 is introduced into the piping line L4 and discharged from the adsorption / desorption processing apparatus 100 as a desorption gas.

  The desorption gas discharged from the adsorption / desorption processing apparatus 100 is sent to the separation apparatus 200 via the piping line L4. The desorption gas sent to the separation device 200 is first introduced into the membrane separation device 210. In the membrane separation device 210, desorption gas is introduced from the piping line L4 through the inlet 215 provided in the shell 211, and the introduced desorption gas contacts the separation membrane 212 when passing through the inside of the shell 211. To do. At this time, water vapor contained in the desorption gas permeates through the separation membrane 212 by the action of a vacuum pump (not shown) and is introduced into the hollow interior of the separation membrane 212, and further, membrane separation is performed via the suction pipe 214 by the action of the vacuum pump. It is discharged to the outside of the device 210. The water vapor discharged from the membrane separation device 210 is supplied to the condenser 220 via the piping line L5, and is condensed by being cooled by the condenser 220 to be separated water, and is discharged via the piping line L6. . On the other hand, the desorption gas after passing through the inside of the shell 211 is introduced into the piping line L7 as a separation gas through the outlet 216 provided in the shell 211 and is discharged from the membrane separation device 210.

  The separation gas discharged from the membrane separation device 210 is sent to the condensation recovery device 300 via the piping line L7. The separated gas sent to the condensing and collecting apparatus 300 is first introduced into the condenser 310 and cooled. The liquid containing the high-concentration organic solvent condensed and liquefied by being cooled is discharged as a recovered liquid through the piping line L8 and stored in the recovery tank 320. Thereafter, the recovered liquid stored in the recovery tank 320 is discharged to the outside of the organic solvent recovery system 1A via the piping line L9 when a predetermined amount is stored.

  By using the organic solvent recovery system 1A in the present embodiment described above, the desorption gas discharged from the adsorption / desorption treatment apparatus 100 is condensed in the membrane separation apparatus 210 of the separation apparatus 200 before being condensed in the condensation recovery apparatus 300. Since it is possible to selectively separate the water vapor contained in the desorption gas from the desorption gas in the membrane separation apparatus 210, the time during which the organic solvent and the water vapor or water are mixed is made as short as possible. Can do. That is, by separating the desorption gas into an organic solvent and water vapor at an early stage, the contact time between the organic solvent that generates acid by reacting with water and water or water vapor can be greatly increased compared to conventional organic solvent recovery systems. It is possible to effectively reduce the occurrence of a reaction that generates an acid. Therefore, by using the organic solvent recovery system 1A in the present embodiment described above, it is possible to recover the organic solvent in high concentration and high yield while suppressing the generation of acid.

  In particular, the reaction in which the acid is generated has progressed remarkably because the organic solvent and water coexist in the separation tank of the condensation recovery apparatus in the conventional organic solvent recovery system in a state where the organic solvent and water coexist for a long time. . Therefore, in the conventional organic solvent recovery system, the reaction in which the acid is generated in the separation tank has progressed particularly after the operation of the facilities such as nighttime is stopped. However, the organic solvent recovery system 1A in the present embodiment described above. Then, since the coexistence state of the organic solvent and water in such a separation tank does not exist in the first place, the generation of acid can be reliably suppressed.

  In the following, the verification test conducted to verify the effect of the present invention will be described in detail. In this verification test, the organic solvent recovery system 1A according to the present embodiment described above as an example is prototyped, and when the organic solvent is recovered using this system, the concentration of the acid contained in the recovered liquid is measured. In addition, the conventional organic solvent recovery system described above as a comparative example is manufactured, and when the organic solvent is recovered using this system, the concentration of the acid contained in the recovered liquid is measured and these results are compared. Thus, the effect of the present invention was verified.

  FIG. 3 is a system configuration diagram of the organic solvent recovery system according to the comparative example, and FIG. 4 is a table showing the results of the verification test. In the following, first, the configuration of the organic solvent recovery system according to the comparative example will be described in detail with reference to FIG. 3, and then the result of the verification test will be described with reference to FIG.

  The organic solvent recovery system 1B according to the comparative example is different from the organic solvent recovery system according to the embodiment (the organic solvent recovery system 1A shown in FIG. 1) except for the adsorption / desorption processing apparatus 100. That is, the organic solvent recovery system 1B according to the comparative example includes a liquid separation recovery device 400 instead of the separation device 200 and the condensation recovery device 300 of the organic solvent recovery system 1A according to the embodiment.

  The liquid separation collection device 400 includes a capacitor 410 and a separator 420. The condenser 410 is a device that condenses and liquefies the desorption gas using cooling water or the like, and the separator 420 separates the liquid obtained by liquefying the desorption gas based on the specific gravity difference, thereby separating the organic solvent. It is an apparatus for separating the recovered liquid and the separated water contained in a high concentration.

  The capacitor 410 is connected to the piping lines L4 and L10, and the separator 420 is connected to the piping lines L10, L11, and L12. The piping line L4 is a piping line for supplying the desorption gas discharged from the adsorption / desorption processing apparatus 100 to the capacitor 410, and the piping line L10 is a piping for supplying the liquid generated by the capacitor 410 to the separator 420. Line. The piping line L11 is a piping line for discharging the recovered liquid separated by the separator 420 from the separator 420, and the piping line L12 is a piping for discharging the separated water separated by the separator 420 from the separator 420. Line.

  In the organic solvent recovery system 1B according to the comparative example, the desorption gas discharged from the adsorption / desorption processing device 100 is introduced into the liquid separation recovery device 400 via the piping line L4. The introduced desorption gas is sent to the condenser 410 to be condensed and liquefied. The liquid generated in the condenser 410 is sent to the separator 420 via the piping line L10, and is separated based on the specific gravity difference in the separator 420, and separated into a recovered liquid containing a high concentration of organic solvent and separated water. Is done. The recovered liquid containing the organic solvent at a high concentration is introduced into the pipe line L11 and discharged and recovered from the liquid separation recovery apparatus 400, and the separated water is introduced into the pipe line L12 and discharged from the liquid separation recovery apparatus 400. The

In this verification test, a 40 ° C. gas to be treated containing ethyl acetate at a concentration of 2000 ppm was used as an organic solvent that generates acid by reacting with water, and this was used as an organic solvent recovery system 1A according to the example and comparison. The treatment was performed by introducing each into the organic solvent recovery system 1B according to the example. Here, the same adsorption / desorption treatment apparatus 100 is used in any organic solvent recovery system, and the adsorbents 111 and 121 have an average pore diameter of 17.4 mm, a BET specific surface area of 1650 m ² / g, Activated carbon fibers having a pore volume of 0.66 cm ³ / g were used.

First, the gas to be treated is adsorbed by blowing air at a flow rate of 100 Nm ³ / min for 10 minutes to one treatment tank of the adsorption / desorption treatment apparatus 100 using a blower (not shown) to clean and treat the gas to be treated. It was discharged as gas. In this case, the concentration of ethyl acetate contained in the processing gas discharged from the adsorption / desorption processing apparatus 100 is 20 ppm in both the organic solvent recovery system 1A according to the example and the organic solvent recovery system 1B according to the comparative example. It was confirmed that the ethyl acetate was removed by the adsorption / desorption treatment apparatus 100 at a removal rate of 99%.

  After the above-mentioned 10 minutes of blowing, the valves V101 to V106 were switched to switch the one processing tank to the desorption tank, and the remaining processing tank was used as an adsorption tank. In the desorption tank, the adsorbent was desorbed by introducing water vapor, and in the adsorption tank, the adsorption process was performed under the same conditions as described above. This operation of adsorption treatment and desorption treatment was repeated alternately in each treatment tank.

  In the organic solvent recovery system 1A according to the embodiment, a carbon membrane having a hollow fiber structure is used as the separation membrane 212 of the membrane separation device 210, and the desorption gas at 100 ° C. discharged from the desorption tank is supplied to the membrane separation device 210. Then, it was separated into ethyl acetate and water vapor by a vapor permeation separation method. Thereafter, a separation gas containing ethyl acetate at a high concentration was introduced into the condensing and collecting apparatus 300, cooled with cooling water at 32 ° C. and condensed to obtain a recovered liquid containing ethyl acetate at a high concentration. As a result of analyzing the concentration of the obtained recovered liquid, the content of ethyl acetate in the recovered liquid was 99.15 wt%, the concentration of acetic acid was 502 ppm, the concentration of ethanol was 248 ppm, and the content of water was It was confirmed that it was 0.1 wt% (see FIG. 4).

  In the organic solvent recovery system 1B according to the comparative example, the 100 ° C. desorption gas discharged from the desorption tank is introduced into the liquid separation recovery device 400, cooled and condensed with 32 ° C. cooling water, and the condensed liquid is recovered. A separation liquid containing ethyl acetate at a high concentration was obtained by liquid separation in the separation tank 420. As a result of analyzing the concentration of the obtained recovered liquid, the content of ethyl acetate in the recovered liquid was 96.85 wt%, the concentration of acetic acid was 994 ppm, the concentration of ethanol was 506 ppm, and the content of water was It was confirmed that it was 3.0 wt% (see FIG. 4).

  From the above results, by using the organic solvent recovery system 1A according to the example, the ethyl acetate is produced in a high concentration and high yield while suppressing the generation of acetic acid as compared with the organic solvent recovery system 1B according to the comparative example. It was confirmed that it can be recovered at the same time.

  In the organic solvent recovery system according to the present embodiment described above, components such as a fluid transporting unit such as a pump and a fan and a fluid storage unit such as a storage tank have been described without particularly showing details. What is necessary is just to arrange | position a component in an appropriate position as needed.

  Further, in the organic solvent recovery system in the present embodiment described above, as the adsorption / desorption treatment device, two treatment tanks containing adsorbents are provided, and these are alternately switched to the adsorption tank and the desorption tank over time. However, in the case where it is not always necessary to continuously process the gas to be treated, an adsorption / desorption treatment apparatus is used. You may comprise with what comprised the single processing tank. In addition, when it is necessary to continuously process the gas to be treated, instead of the above-described switching type adsorption / desorption treatment apparatus, a part of the adsorbent is used as an adsorption treatment zone and the remaining part of the adsorbent is used. It is also possible to use an adsorption / desorption treatment apparatus equipped with a rotary adsorbent that is used as a desorption treatment zone, and that the adsorption treatment zone and the desorption treatment zone move gradually with the rotation of the adsorbent. Good.

  Thus, the one embodiment disclosed this time is illustrative in all respects and is not restrictive. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1A Organic solvent recovery system, 100 adsorption / desorption treatment device, 110 first treatment tank, 111 adsorbent, 120 second treatment tank, 121 adsorbent, 200 separation device, 210 membrane separation device, 211 shell, 212 separation membrane, 213a, 213b Support member, 214 suction pipe, 215 inlet, 216 outlet, 220 condenser, 300 condensing recovery device, 310 condenser, 320 recovery tank, L1-L9 piping line, V101-V106 valve.

Claims (6)

An organic solvent recovery system for recovering the organic solvent from a gas to be treated containing an organic solvent that generates an acid by reacting with water,
It includes an adsorbing element that adsorbs an organic solvent by contacting a gas to be treated, and desorbs the adsorbed organic solvent by bringing a heated gas into contact with the organic solvent. An adsorption / desorption treatment apparatus that adsorbs the adsorption element and discharges it as a processing gas, and supplies a heating gas to the adsorption element to desorb the organic solvent from the adsorption element and discharge it as a desorption gas containing the organic solvent;
A separation membrane that selectively permeates and separates water vapor contained in the desorption gas by contacting the desorption gas, and supplies the desorption gas discharged from the adsorption / desorption treatment apparatus to the separation membrane; A membrane separation device for separating and discharging into a separation gas containing water and water vapor;
An organic solvent recovery system comprising: a condensation recovery device that condenses by cooling the separation gas discharged from the membrane separation device and recovers it as a recovery liquid containing the organic solvent at a high concentration.   The organic solvent recovery system according to claim 1, wherein the adsorption element is activated carbon fiber.   The organic solvent recovery system according to claim 1, wherein the heated gas is water vapor.   The organic solvent recovery system according to any one of claims 1 to 3, wherein the separation membrane is a carbon membrane.   The organic solvent recovery system according to any one of claims 1 to 4, wherein the separation membrane has a hollow fiber structure.   The organic solvent recovery system according to any one of claims 1 to 5, wherein the gas to be treated contains at least one of acetate ester and a basic compound as an organic solvent.

Images