JP2018161603A - Organic solvent recovery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To significantly reduce the amount of inert gas used in a system in which an adsorption treatment and a desorption treatment are alternately performed to cool and condense the inert gas discharged in the desorption treatment to liquefy and recover an organic solvent. Provide an organic solvent recovery system. SOLUTION: In the organic solvent recovery system 300A of the present invention, an inert gas is transferred from a first treatment tank 102 before switching to the adsorption treatment after the desorption treatment to a gas tank 109, and the desorption treatment is switched to after the adsorption treatment. The inert gas stored in the gas tank 109 is transferred to the previous first treatment tank 102. [Selection diagram] Fig. 1

Description

  The present invention comprises an apparatus for adsorbing and removing an organic solvent from a gas to be treated containing the organic solvent, desorbing the adsorbed organic solvent with an inert gas, and an apparatus for recovering the desorbed organic solvent by liquefaction condensation. The present invention relates to an organic solvent recovery system.

  With the tightening of emission concentration regulations for harmful air pollutants, demand for organic solvent-containing gas treatment devices is increasing. Among them, an organic solvent recovery system that liquefies and recovers an organic solvent has advantages such as a smaller amount of carbon dioxide emission than a combustion device that burns and detoxifies the organic solvent, and the recovered organic solvent can be reused. In recent years, a low drainage type organic solvent recovery system having a low drainage amount for the purpose of improving the quality of the recovered organic solvent and simplifying the wastewater treatment process has been desired.

  The conventional low drainage organic solvent recovery system has an adsorption process that adsorbs and removes the organic solvent in the gas to be treated with an adsorbent, and a desorption process that desorbs the organic solvent adsorbed on the adsorbent by an inert gas such as heated air. And switching means for alternately performing the adsorption step and the desorption step in terms of time or means for continuously performing the adsorption step and the desorption step.

  As such an organic solvent recovery system, for example, Patent Document 1 includes two pairs of treatment tanks that use activated carbon fibers as an adsorbent and alternately switch between adsorption and desorption of an organic solvent in a gas to be treated. An apparatus for supplying a heated inert gas to one treatment tank and desorbing the organic solvent from the adsorbent, and then liquefying and recovering the organic solvent contained in the inert gas discharged from the treatment tank by a condenser Has been proposed. In the apparatus, a circulation path is provided in which the inert gas containing the unconcentrated organic solvent discharged from the condenser is heated again and supplied to the treatment tank. Since the concentration of the organic solvent in the circulation path is high and may exceed the lower limit of the explosion limit, it is necessary to reduce the oxygen concentration in the circulation path to an incombustible region with an inert gas. For this reason, a purge process is required in which the inside of the treatment tank that is always introduced into the circulation path is filled with an inert gas before switching from the adsorption process to the desorption process.

JP 2013-128905 A

  However, the conventional system requires a supply of an inert gas corresponding to the volume of the processing tank in the purge process, and there is a problem that a large inert gas generator is required.

  Therefore, the present invention has been made in view of the above problems, and alternately performs an adsorption process and a desorption process, cools and condenses the inert gas discharged by the desorption process, liquefies and recovers the organic solvent, and circulates the inert gas. The purpose is to greatly reduce the amount of inert gas used.

As a result of intensive studies to solve the above problems, the present inventors have finally completed the present invention. That is, the present invention is as follows.
1. A first treatment tank containing a first adsorbent is provided, an adsorbing treatment for adsorbing and removing an organic solvent from a gas to be treated containing an organic solvent by an adsorbent and discharging a clean gas, and an adsorbent adsorbing the organic solvent A first adsorption / desorption treatment device that alternately performs a desorption process of desorbing with an inert gas and discharging an inert gas containing an organic solvent;
A condenser that condenses the inert gas containing the organic solvent discharged from the first adsorption / desorption treatment device and recovers the organic solvent;
In the organic solvent recovery system comprising a first temperature adjusting means for heating the inert gas discharged from the condenser when being supplied to the first adsorption / desorption treatment device, on the circulation path,
Gas storage means connected to the first treatment tank;
The inert gas is transferred from the first processing tank before switching to the adsorption process after the desorption process to the gas storage means, and the gas storage means is transferred to the first processing tank before switching to the desorption process after the adsorption process. An organic solvent recovery system comprising: an inert gas transfer means for transferring a stored inert gas.
2. 2. The organic solvent recovery system according to 1 above, wherein the transfer means transfers the inert gas by pressure operation.
3. By supplying the outside air or the gas to be treated to the first treatment tank, the inert gas is transferred from the first treatment tank to the gas storage means, and the outside air or the gas to be treated is supplied to the gas storage means. 3. The organic solvent recovery system according to 1 or 2 above, wherein an inert gas is transferred from the gas storage means to the first treatment tank by supplying the gas.
4). The first adsorption / desorption treatment device comprises two first treatment tanks, and continuously purifies the gas to be treated by alternately performing the adsorption treatment in the two first treatment tanks,
The inert gas transfer means transfers the inert gas from one of the first processing tanks before switching to the adsorption process after the desorption process, and before switching to the desorption process after the adsorption process. 4. The organic solvent recovery system according to any one of 1 to 3 above, wherein the inert gas stored in the gas storage means is transferred to the other first processing tank.
5. Second adsorption / desorption comprising a second treatment tank containing a second adsorbent, wherein the second adsorbent adsorbs and desorbs an uncondensed organic solvent contained in the inert gas discharged from the condenser. A processing device;
A second temperature adjusting means for adjusting the temperature when supplying an inert gas containing an uncondensed organic solvent discharged from the condenser to the second adsorption / desorption treatment device;
The second adsorption / desorption treatment apparatus is configured to bring the high temperature inert gas and the low temperature inert gas temperature-adjusted by the second temperature adjusting means into contact with the second adsorbent alternately in time, Move the organic solvent from the cold inert gas to the hot inert gas,
The second temperature adjusting means adjusts the temperature of an inert gas containing an uncondensed organic solvent discharged from the condenser to a high temperature in the first stage of the desorption treatment with the first adsorbent, and performs the first adsorption. 5. The organic solvent recovery system according to any one of 1 to 4 above, wherein an inert gas containing an uncondensed organic solvent discharged from the condenser is adjusted to a low temperature in a later stage of desorption treatment with a material.
6). Any one of 1 to 5 above, wherein the circulation path includes a heat exchanger that performs heat exchange between the inert gas discharged from the first organic solvent recovery device and the inert gas discharged from the condenser. Organic solvent recovery system described in 1.

  According to the organic solvent recovery system of the present invention, the supply amount of the inert gas used for the purge process before switching from the adsorption process to the desorption process can be greatly reduced, and the inert gas generator can be downsized.

It is a figure which shows the structure of the organic-solvent collection | recovery system of one Embodiment of this invention. It is a figure which shows the structure of the organic-solvent collection | recovery system of other embodiment of this invention. It is a figure which shows the structure of the organic-solvent collection | recovery system of another embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the same or common parts are denoted by the same reference numerals in the drawings, and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a configuration diagram of an organic solvent recovery system 300A according to the first embodiment. The organic solvent recovery system 100A cleans and discharges the processing gas by separating the organic solvent from the processing gas containing the organic solvent, and recovers the organic solvent separated from the processing gas using an inert gas. System.

  As shown in FIG. 1, the organic solvent recovery system 300A includes a circulation path CP composed of piping lines L1 to L3 arranged so that an inert gas circulates as shown in FIG. A first adsorption / desorption treatment device 100 and a condenser 103 are provided. Furthermore, a gas tank (gas storage means) 109 is provided. In addition, a circulation blower 201 is provided.

  The inert gas used in the organic solvent recovery system 100A is preferably at least one of nitrogen, argon, helium, neon, xenon, radon, and carbon dioxide, but is not particularly limited.

  Further, in the organic solvent recovery system 300A, an introduction line L0 for introducing an inert gas from outside the circulation path CP to the circulation path is provided. The introduction line L9 is used to introduce an inert gas into the circulation path CP when the organic solvent recovery system 300A is initially installed, or to replenish a carrier gas to the circulation path CP as necessary during maintenance.

  The first adsorption / desorption treatment apparatus 100 is an apparatus that treats a gas to be treated (organic solvent-containing gas) and discharges a clean gas (treated gas). As shown in FIG. 1, the first adsorption / desorption treatment apparatus 100 includes two first treatment tanks 102A and 102B filled with first adsorbents 101A and 101B, respectively. Hereinafter, when the two first processing tanks 102A and 102B are not distinguished, they are referred to as the first processing tank 102. When the two first adsorbents 101A and 101B are not distinguished, they are referred to as the first adsorbent 101. In the present embodiment, the first adsorption / desorption treatment device 100 includes two first treatment tanks, but the number of the first adsorption / desorption treatment devices 100 is not limited and may be one or three or more.

  The first adsorbent 101 preferably has at least one selected from activated carbon fibers, granular activated carbon, spherical activated carbon, hydrophobic silica gel, and hydrophobic zeolite. More preferred is activated carbon fiber or hydrophobic zeolite having a low moisture adsorption rate. However, it is not particularly limited.

  The first adsorption / desorption processing apparatus 100 performs an adsorption process (adsorption process) in which an organic compound is adsorbed and removed from a process gas using the first adsorbent 101, and the process gas is cleaned and discharged. Further, a desorption process (desorption process) is performed in which the adsorbed organic compound is desorbed using an inert gas, and the inert gas containing the desorbed organic solvent is discharged.

  The 1st adsorption / desorption processing apparatus 100 is connected to the piping lines L4 and L5, respectively. The piping line L4 is a piping line for supplying to the first processing tank 102 the gas to be processed containing the organic solvent introduced by the blower 200 through the piping line L6. The dampers D1 and D3 provided in the first treatment tanks 102A and 102B are switched between a connected state and a non-connected state with respect to the first treatment tank 102A and the first treatment tank 102B. The piping line L5 is a piping line for discharging clean gas from the first processing tank 102, and is connected to the first processing tank 102A and the processing tank 102B by dampers D2 and D4 provided in the first processing tanks 102A and 102B. The state and the disconnected state are switched.

  Moreover, the 1st adsorption / desorption processing apparatus 10 is connected to the piping lines L3 and L1, respectively. The piping line L <b> 3 is a piping line for supplying an inert gas to the first processing tank 102 via the first heater (first temperature adjusting means) 107. The piping line L3 is switched between a connected state and a disconnected state with respect to the first processing tank 102A by the control valve V210, and a connected state and a disconnected state with respect to the first processing tank 102B by the V211. The piping line L <b> 1 is a piping line for discharging the inert gas from the first processing tank 102.

  The inert gas discharged from the first treatment tank 102 is condensed in the condenser 103. The condenser 103 is a device that cools and condenses the organic solvent contained in the inert gas by adjusting the temperature of the inert gas to a low temperature state. The condenser 103 is connected to the separator 108. The separator 108 is a tool for separating the organic solvent condensed by the condenser and water. The inert gas remaining without being condensed in the condenser 103 is discharged from the piping line L <b> 2 connected to the condenser 103.

A circulation blower 201 is provided at the end of the piping line L2. The circulation fan 201 is a blowing means for causing the inert gas to flow through the circulation path CP. In addition, a piping line LO is connected to the circulation fan 201. The circulation fan 201 sets the flow rate of the inert gas appropriately. A plurality of circulation fans may be provided in the circulation path L1.
The inert gas blown by the circulation blower 201 is introduced into the treatment tanks 102 </ b> A and 102 </ b> B of the first adsorption / desorption treatment apparatus 100 through the first heater 107.

  The organic solvent recovery system 100A further includes a gas tank 109 that temporarily stores an inert gas.

  The gas tank 109 is connected to the first adsorption / desorption processing device 10 by a piping line L7. The piping line L7 transfers the inert gas in the first treatment tank 102 after the desorption process and before the adsorption process to the gas tank 109, and also transfers the inert gas from the gas tank 109 to the treatment tank 102 after the adsorption process and before the desorption process. This is a path for transferring the active gas. The piping line L7 is switched between connection and non-connection with the first treatment tank 102A by the control valve V203, and connection and non-connection with the first treatment tank 102B by the control valve V205.

  The 1st adsorption / desorption processing apparatus 100 is connected to the piping line L8. The piping line L8 is a path for introducing outside air or gas to be processed into the first processing tank 102 in order to push out the inert gas in the first processing tank 102 after the desorption process and before the adsorption process. The outside air or the gas to be processed is blown by the extrusion blower 202 through the piping line L9 and introduced into the first processing tank 102 from the piping line 8. The piping line L8 is switched between connection and non-connection with the first treatment tank 102A by the control valve V202 and control valve V024, and connection and non-connection with the first treatment tank 102B by the control valve V202 and control valve V205. .

  The inert gas pushed out from the first treatment tank 102 is introduced into the gas tank 109 via the piping line L7. When the gas exceeding the remaining capacity of the gas tank 109 is introduced, the gas flows to the piping line L6 via the piping line L10 connected to the gas tank 109. The pipe line L10 is switched between connection and non-connection with the gas tank 109 by the control valve V209.

  The gas tank 109 is connected to the piping line L11. The piping line L11 is used to push out the inert gas stored in the gas tank 109 and transfer it to the first processing tank 102 after the adsorption process and before the desorption process. It is a route. The outside air or the gas to be treated is blown by the extrusion blower 202 through the piping line L9 and introduced into the gas tank 109 from the piping line 11. The piping line L11 is switched between connection and disconnection with the gas tank 109 by the control valve V0201.

  The inert gas pushed out from the gas tank 109 is introduced into the first treatment tank 102 via the piping line L7. When the gas exceeding the remaining capacity of the first processing tank 102 is introduced, the gas flows into the piping line L6 via the piping line L12 connected to the first processing tank 102. The piping line L12 is switched between connection and non-connection with the first processing tank 102A by the control valve V204, and connection and non-connection with the first processing tank 102B by the control valve V206.

  The volume of the gas tank 109 is preferably not less than ½ times and not more than twice the volume of the first treatment tank 102. More preferably, it is 3/4 times or more and 1.25 times or less. If the volume of the gas tank 109 is less than ½ times the volume of the first processing tank 102, the storage capacity of the inert gas in the gas tank 109 is small, and the effect of reducing the supply amount of the inert gas is halved. Further, if the volume of the gas tank 109 is larger than twice the volume of the first processing tank 100, the inert gas concentration in the gas tank 109 becomes lean, and the effect of reducing the inert gas supply amount is halved.

  The volume of the outside air or the gas to be processed supplied to the first treatment tank 102 or the gas tank 109 is preferably ½ to 2 times the capacity of the gas tank 109. More preferably, the amount is 3/4 times to 1.25 times. If the amount is less than ½ times or more than twice the amount, the inert gas concentration in the gas tank 109 becomes lean, and the effect of reducing the amount of inert gas supplied is halved.

  The inert gas is preferably transferred by pressure. By performing the pressure operation, the space can be saved by downsizing the gas tank 109. Moreover, the inert gas to be transferred can be kept at a high purity.

  Next, the transfer of the inert gas in the organic solvent recovery system 300A will be described. Hereinafter, the case where the adsorption process is performed in the first processing tank 102A and the desorption process is performed in the first processing tank 102B will be described as an example. The same applies to the reverse case where the desorption process is executed in the first processing tank 102A and the adsorption process is executed in the first processing tank 102B.

  After completing the desorption process by the first adsorbent 101B in the first treatment tank 102B, the control valves V202, V206, V205, V209 are opened, the extrusion blower 202 is operated, and the first process is performed through the piping line L9 and the piping line L8. The volume of the outside air or the gas to be processed is introduced into the tank 102B, for example, the same volume as the volume of the first processing tank 102B. As a result, the nitrogen gas in the first treatment tank 102B is pushed out, transferred to the gas tank 108 through the piping line L7, and stored. After the storage is completed, the control valves V202, V206, V205, and V209 are closed, and the first processing tank 102B is switched to perform the adsorption process.

  Subsequently, the control valves V201, V203, V204 are opened, the extrusion blower 202 is operated, and the nitrogen gas in the gas tank 109 is supplied to the first processing tank 102A. By supplying nitrogen gas from the gas tank 109, the amount of inert gas generated by a nitrogen generator (not shown) and supplied through the piping line L0 can be reduced. Then, if necessary, it is generated by a nitrogen generator and an inert gas is supplied through the piping line L0. Thus, the purge process of the first treatment tank 102A is performed using the nitrogen gas in the gas tank 109 and the nitrogen gas generated by the nitrogen generator as necessary. After completion of the purge process in the first processing tank 102A, the control valves V201, V203, V204 are closed, and switching is performed so that the first processing tank 102A performs the desorption process. As described above, the organic solvent recovery system 300A continuously processes the gas to be processed by alternately switching the adsorption process and the desorption process.

  Here, the organic solvents that can be processed by the organic solvent recovery system 100A are methylene chloride, chloroform, carbon tetrachloride, ethylene chloride, trichloroethylene, tetrachloroethylene, O-dichlorobenzene, m-dichlorobenzene, Freon-112, Freon-113, HCFC. , HFC, propyl bromide, butyl iodide, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, vinyl acetate, methyl propionate, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, diethyl carbonate, formic acid Ethyl, diethyl ether, dipropyl ether, tetrahydrofuran, dibutyl ether, anisole, methanol, ethanol, isopropanol, n-butanol, 2-butanol, isobutanol, t-butanol, allyl alcohol , Pentanol, heptanol, ethylene glycol, diethylene glycol, phenol, O-cresol, m-cresol, p-cresol, xylenol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, phorone, acrylonitrile, n-hexane, isohexane, cyclohexane, Methylcyclohexane, n-heptane, n-octane, n-nonane, isononane, decane, dodecane, undecane, tetradecane, decalin, benzene, toluene, m-xylene, p-xylene, o-xylene, ethylbenzene, 1, 3, 5 -Refers to trimethylbenzene, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide and the like.

  As described above, in the organic solvent recovery system 300A, when the first processing tank 102B is switched from the desorption process to the adsorption process, the inert gas discharged from the first processing tank 102B to the outside of the system is stored in the gas tank 109. By supplying the inert gas stored in the gas tank 109 to the first treatment tank 102A during the purge process of the first treatment tank 102A, the supply amount of the newly used inert gas can be greatly reduced. Similarly, when the first treatment tank 102A is switched from the desorption process to the adsorption process, the inert gas discharged outside the system is stored in the gas tank 109, and in the gas tank 109 during the purge process of the first treatment tank 102B. By supplying the stored inert gas to the first treatment tank 102B, it is possible to significantly reduce the supply amount of the newly used inert gas.

  In a system equipped with one first treatment tank 102, when switching from the desorption process to the adsorption process, the inert gas is transferred from the first treatment tank 102 to the gas tank 109 for storage and reused. Thus, the purge process of the first treatment tank 102 may be performed. Further, in the system having three or more tanks, the inert gas is transferred from the first treatment tank 102 that switches from the desorption process to the adsorption process to the gas tank 109, and the inert gas is switched from the adsorption process to the desorption process from the gas tank 109. What is necessary is just to implement the process of supplying to the 1 process tank 102 in order.

[Embodiment 2]

  The configuration of the organic solvent recovery system 300B of the second embodiment is shown in FIG. In addition to the configuration of the organic solvent recovery system 300A described in the first embodiment, the organic solvent recovery system 300B includes a second adsorption / desorption processing device 110 and a temperature controller 110 and a second adsorption / desorption processing device after the condenser 103. 112. Since the configuration other than these is the same as that of the organic solvent recovery system 300A, the same reference numerals are given and the description thereof is omitted.

  The temperature controller 110 includes a piping line L13, a piping line L14, a piping line L15, and a heater 104. The temperature controller 110 is a device that adjusts the temperature of the inert gas discharged from the condenser 103 through the piping line L <b> 2 and discharges it to the second adsorption / desorption processing device 112.

  The second adsorption / desorption processing device 112 includes a second adsorption tank 106 filled with the second adsorbent 105. The second adsorbent 105 preferably has at least one selected from activated carbon fiber, granular activated carbon, spherical activated carbon, hydrophobic silica gel, and hydrophobic zeolite, and more preferably activated carbon fiber or hydrophobic having a low moisture adsorption rate. Although it is a zeolite, it is not specifically limited.

  The second adsorption / desorption processing device 112 performs an adsorption process for adsorbing and removing an organic compound from the inert gas using the second adsorbent 105. Further, a desorption process is performed in which the adsorbed organic compound is desorbed using an inert gas.

  In the latter stage of the desorption process in the first treatment tank 102, the inert gas discharged from the condenser 103 due to the adsorption action of the second adsorbent 105 is directly supplied to the second treatment tank 106 at a low temperature via the pipe line L3. To introduce. Thereby, the organic solvent contained in the inert gas discharged from the condenser 103 is adsorbed by the second adsorbent 105, the concentration of the organic solvent in the inert gas can be reduced, and the organic solvent-containing inert gas having a lower concentration Thus, the first adsorbent 101 can be desorbed and regenerated. Therefore, the desorption efficiency of the first adsorbent 101 is greatly improved.

  Further, in the first stage of the desorption process in the first treatment tank 102, the inert gas discharged from the condenser 103 is introduced into the heater 104 via the piping line L104 and heated by the heater 104 to be heated at a high temperature. Gas is supplied to the second treatment tank 106. Thereby, desorption regeneration of the 2nd adsorption material 105 can be performed.

  As described above, in the organic solvent recovery system 300B, the first adsorbent 101 can always be desorbed and regenerated with high efficiency by the switching operation between the adsorption and desorption of the second adsorbent in the second adsorption / desorption device 112.

  The inert gas that can be used in the organic solvent recovery system 300B is the same as that that can be used in the organic solvent recovery system 300A. The organic solvent that can be processed by the organic solvent recovery system 300B is the same as the organic solvent that can be processed by the organic solvent recovery system 300A.

[Embodiment 3]
The configuration of an organic solvent recovery system 300C according to Embodiment 3 is shown in FIG. In addition to the configuration of the organic solvent recovery system 300A described in the first embodiment, the organic solvent recovery system 300C is condensed with an inert gas discharged from the first processing tank 102 in which the desorption process is performed in the circulation path CP. The heat exchanger 111 which performs heat exchange with the inert gas discharged | emitted from the container 103 is provided. Since the configuration other than this is the same as that of the organic solvent recovery system 300A, the same reference numerals are given and description thereof is omitted.

  The inert gas discharged from the first processing tank 102 through the piping line L1 is heated by the heat exchanger 111 and introduced into the condenser 103 through the piping line L17. The inert gas discharged from the condenser 103 via the piping line L2 is deprived of heat by the heat exchanger 111 and introduced into the circulation fan 201 via the piping line L18. With this configuration, the organic solvent recovery system 300C can greatly reduce energy such as the amount of cold water used in the condenser 103 and the amount of steam used for heating the inert gas.

  The active gas that can be used in the organic solvent recovery system 300C is the same as that that can be used in the organic solvent recovery system 300A. The organic solvent that can be processed by the organic solvent recovery system 300C is the same as the organic solvent that can be processed by the organic solvent recovery system 300A.

  Hereinafter, the present invention will be described in more detail with reference to examples using the organic solvent treatment system described in the above embodiment. However, the present invention is not limited to the following examples.

<Example 1>
In Example 1, the organic solvent recovery system 300B described in Embodiment 2 was used. As the adsorbents 101A and 101B, Toyobo's activated carbon fiber “K-FILTER” was used.

  Hereinafter, the case where the adsorption process is performed in the first processing tank 102A and the desorption process is performed in the first processing tank 102B will be described as an example. The same applies to the reverse case where the desorption process is executed in the first processing tank 102A and the adsorption process is executed in the first processing tank 102B.

Adsorption in which gas to be treated of 35 ° C. and 47% RH containing 2000 ppm of ethyl acetate is supplied to the organic solvent recovery system 300B at 7 Nm ³ / min, and is passed through the first treatment tank 102A to adsorb and remove the adsorbent ethyl acetate. Processed. While ethyl acetate in the gas to be treated is adsorbed by the first adsorbent 101A, the first treatment tank 102B converts the ethyl acetate adsorbed by the adsorbent 101B to nitrogen gas (inert gas) heated to 120 ° C. The desorption process to desorb was performed.

  Nitrogen gas containing ethyl acetate desorbed from the first adsorbent 101B of the first treatment tank 102B is cooled to 10 ° C. in the condenser 103 through the piping line L1, thereby obtaining liquefied and condensed ethyl acetate. It was. In the first stage of the desorption process in the first treatment tank 102B, low-temperature nitrogen gas containing unconcentrated ethyl acetate discharged from the condenser 103 is sent to the second heater 104 through the piping line L2 and the piping line L4, The two heaters 104 were heated to 120 ° C. and supplied to the second adsorbent 105 in the second treatment tank 106. At this time, ethyl acetate adsorbed on the second adsorbent 105 in the latter stage of the desorption process in the first treatment tank 102A is desorbed, and nitrogen gas containing ethyl acetate is discharged from the second treatment tank 106. The Nitrogen gas containing ethyl acetate discharged from the second treatment tank 106 was heated to 120 ° C. by the first heater 107 and supplied to the first adsorbent from the piping line L3.

  In the latter stage of the desorption process in the subsequent first treatment tank 102B, low-temperature nitrogen gas containing unconcentrated ethyl acetate discharged from the condenser 103 is directly supplied to the second treatment tank 106 through the piping line L2 and the piping line L3. Supplied. At this time, ethyl acetate contained in the low-temperature condenser outlet gas L2 is adsorbed and removed by the second adsorbent 105 of the second processing tank 106, and nitrogen gas with a reduced ethyl acetate concentration is discharged from the second processing tank 106. It was. The low concentration nitrogen gas discharged from the second treatment tank 106 was heated to 120 ° C. by the first heater 107 and circulated and supplied to the first adsorbent 101B of the first treatment tank 102B. By the latter stage of the desorption process in the first treatment tank 102B, the ethyl acetate of the first adsorbent 101B could be desorbed with high efficiency.

  After completing the desorption process by the first adsorbent 101B in the first treatment tank 102B, the control valves V202, V206, V205, V209 are opened, the extrusion blower 202 is operated, and the first process is performed through the piping line L8 and the piping line L9. The gas to be processed was introduced into the tank 102B in the same volume as the volume of the first processing tank 102B. As a result, the nitrogen gas in the first treatment tank 102B was pushed out, transferred to the gas tank 108 through the piping line L7, and stored. After the storage was completed, the first processing tank 102B was switched to perform an adsorption process.

  Subsequently, the control valves V201, V203, V204 were opened, the extrusion blower 202 was operated, and the nitrogen gas in the gas tank 109 was supplied to the first processing tank 102A. By supplying the nitrogen gas from the gas tank 109, the amount of nitrogen gas generated by a nitrogen generator (not shown) and supplied through the piping line L0 could be reduced. Thereafter, nitrogen gas generated by the nitrogen generator and supplied through the piping line L0 until the oxygen concentration became 3% or less was supplied to the first treatment tank 102A. As described above, the purge treatment of the first treatment tank 102A was performed using the nitrogen gas in the gas tank 109 and the nitrogen gas generated by the nitrogen generator. After completion of the purge process in the first processing tank 102A, the first processing tank 102A was switched to perform the desorption process. In this way, the gas to be treated containing ethyl acetate was continuously treated by alternately switching the adsorption treatment and the desorption treatment. Table 1 shows the amounts of nitrogen, cold water, and steam used at this time.

<Example 2>
In Example 2, a system in which the heat exchanger 111 shown in FIG. 3 was provided in the circulation path CP in the organic solvent recovery system 300B shown in FIG. 2 was used. In this organic solvent recovery system 300B + heat exchanger 111 system, the same operation as in Example 1 was performed except that the heat was exchanged between the desorption outlet gas L1 and the condenser outlet gas L2 from the treatment tanks 102A and 102B. . Table 1 shows the amounts of nitrogen, cold water, and steam used at this time.

<Comparative example>
In the comparative example, a configuration in which the gas tank 109 and the piping line connected to the gas tank 109 are not provided in the system used in the second embodiment was used. That is, the heat exchanger 111 shown in FIG. 3 is added to the machine solvent recovery system 300B shown in FIG. 2, and the gas tank 109 is removed. Using this system, nitrogen gas generated by a nitrogen generator (not shown) and supplied from the piping line L0 is supplied in all purge steps until the oxygen concentration in the first treatment tanks 102A and 102B becomes 3% or less. Except that, the same operation as in Example 1 was performed. Table 1 shows the amounts of nitrogen, cold water, and steam used at this time.

  As can be seen from Table 1, in Examples 1 and 2, by using the organic solvent treatment system provided with the gas tank 109 according to the present invention, the amount of nitrogen used was about 30 compared to the system of the comparative example not provided with the gas tank. % Reduction. Further, in the second embodiment in which the nitrogen gas discharged from the first treatment tanks 102A and 102B and the gas discharged from the condenser 103 are heat-exchanged in the circulation path CP, the amount of cold water used is 40% compared to the first embodiment. The steam consumption was reduced by 29%.

  From these, it can be seen that by using the organic solvent recovery system according to the present invention, the supply amount of the inert gas used in the purge process before switching from the adsorption process to the desorption process can be greatly reduced. Therefore, according to the present invention, an organic solvent recovery system capable of reducing the size of the inert gas generator can be provided.

  It should be noted that each of the disclosed embodiments and examples is illustrative only and not restrictive. In addition, embodiments and examples in which the configurations disclosed in the respective embodiments and examples are appropriately combined are also included in the present invention. In other words, the technical scope of the present invention is effective according to the scope of the claims, and includes all changes, modifications, replacements, etc. within the meaning and scope equivalent to the description of the scope of claims.

  The present invention can be effectively used in a system for recovering an organic compound from a gas to be treated containing an organic compound discharged from various factories, research facilities, or the like.

100 1st adsorption / desorption processing apparatus 101A, 10B 1st adsorption material 102, 102A, 102B 1st processing tank 103 Condenser 104 2nd heater 105 2nd adsorption material 106 2nd adsorption / desorption processing apparatus 107 1st heater (1st temperature) Adjustment means)
108 Condenser 109 Gas tank (gas storage means)
110 Temperature controller (second temperature adjusting means)
111 2nd adsorption / desorption processing apparatus 200 Raw gas blower 201 Circulation blower 202 Extrusion blower (inert gas transfer means)
300A, 300B, 300C Organic solvent recovery system CP Circulation path V201 to V211 Control valve L0 to L12 Piping line

Claims (6)

A first treatment tank containing a first adsorbent is provided, an adsorbing treatment for adsorbing and removing an organic solvent from a gas to be treated containing an organic solvent by an adsorbent and discharging a clean gas, and an adsorbent adsorbing the organic solvent A first adsorption / desorption treatment device that alternately performs a desorption process of desorbing with an inert gas and discharging an inert gas containing an organic solvent;
A condenser that condenses the inert gas containing the organic solvent discharged from the first adsorption / desorption treatment device and recovers the organic solvent;
In the organic solvent recovery system comprising a first temperature adjusting means for heating the inert gas discharged from the condenser when being supplied to the first adsorption / desorption treatment device, on the circulation path,
Gas storage means connected to the first treatment tank;
The inert gas is transferred from the first processing tank before switching to the adsorption process after the desorption process to the gas storage means, and the gas storage means is transferred to the first processing tank before switching to the desorption process after the adsorption process. An organic solvent recovery system comprising: an inert gas transfer means for transferring a stored inert gas.   The organic solvent recovery system according to claim 1, wherein the transfer means transfers the inert gas by pressure operation.   By supplying the outside air or the gas to be treated to the first treatment tank, the inert gas is transferred from the first treatment tank to the gas storage means, and the outside air or the gas to be treated is supplied to the gas storage means. 3. The organic solvent recovery system according to claim 1 or 2, wherein an inert gas is transferred from the gas storage means to the first treatment tank by supplying. The first adsorption / desorption treatment device comprises two first treatment tanks, and continuously purifies the gas to be treated by alternately performing the adsorption treatment in the two first treatment tanks,
The inert gas transfer means transfers the inert gas from one of the first processing tanks before switching to the adsorption process after the desorption process, and before switching to the desorption process after the adsorption process. The organic solvent recovery system according to any one of claims 1 to 3, wherein the inert gas stored in the gas storage means is transferred to the other first processing tank. Second adsorption / desorption comprising a second treatment tank containing a second adsorbent, wherein the second adsorbent adsorbs and desorbs an uncondensed organic solvent contained in the inert gas discharged from the condenser. A processing device;
A second temperature adjusting means for adjusting the temperature when supplying an inert gas containing an uncondensed organic solvent discharged from the condenser to the second adsorption / desorption treatment device;
The second adsorption / desorption treatment apparatus is configured to bring the high temperature inert gas and the low temperature inert gas temperature-adjusted by the second temperature adjusting means into contact with the second adsorbent alternately in time, Move the organic solvent from the cold inert gas to the hot inert gas,
The second temperature adjusting means adjusts the temperature of an inert gas containing an uncondensed organic solvent discharged from the condenser to a high temperature in the first stage of the desorption treatment with the first adsorbent, and performs the first adsorption. 5. The temperature of an inert gas containing an uncondensed organic solvent discharged from the condenser is adjusted to a low temperature in a later stage of the desorption treatment with the material. Organic solvent recovery system.   The heat exchanger for performing heat exchange between the inert gas discharged from the first organic solvent recovery device and the inert gas discharged from the condenser is provided in the circulation path. 6. The organic solvent recovery system according to any one of 5 above.