JP2018030052A - Organic solvent recovery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method which suppresses lowering of absorption performance of adsorption/desorption elements caused by an organic substance remaining on the adsorption/desorption elements, reduces a replacement frequency of the adsorption/desorption elements, and thereby can achieve resource saving.SOLUTION: A method includes: a first adsorption/desorption treatment device having a first adsorption/desorption element which adsorbs and desorbs an organic solvent on a circulation path through carrier gas is circulated; a condensation recovery device which condenses the organic solvent and recovers the condensed organic solvent as a condensate liquid; and a second adsorption/desorption element which adsorbs and desorbs the organic solvent; has a regular path through which carrier gas discharged from the second adsorption/desorption treatment device is introduced into the first adsorption/desorption treatment device, and a bypass through which the carrie gas is introduced into the condensation recovery device not through the first adsorption/desorption treatment device, where the carrier gas discharged from the second adsorption/desorption treatment device is introduced into the condensation recovery device from the bypass for a predetermined period after the end of a first adsorption/desorption treatment period during which the organic solvent is adsorbed and desorbed from the first adsorption/desorption element, and the carrie gas discharged from the condensation recovery device is introduced into the second adsorption/desorption treatment device from a high temperature path.SELECTED DRAWING: Figure 1

Description

  The present invention cleans and discharges the gas to be treated by separating the organic solvent from the gas to be treated containing the organic solvent (organic substance), and collects the organic solvent separated from the gas to be treated using the carrier gas. The present invention relates to an organic solvent recovery system.

  In recent years, the demand for organic solvent-containing gas treatment systems has increased with the tightening of emission concentration regulations for harmful air pollutants. 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.

  This type of organic solvent recovery system is generally discharged from the adsorption / desorption treatment device that alternately contacts the treatment gas containing the solvent and the carrier gas in a high temperature state with the adsorbent in time, and the adsorption / desorption treatment device. And a condensing / recovering device for condensing and recovering the organic solvent by cooling the carrier gas in a high temperature state.

  As one of such systems, Patent Document 1 discloses an organic solvent-containing gas processing system using water vapor as a carrier gas.

  Recently, a low drainage organic solvent recovery system is desired for the purpose of improving the quality of the recovered organic solvent and simplifying the wastewater treatment process. Therefore, Permitted Document 2 discloses an organic solvent-containing gas processing system using an inert gas heated to a high temperature as a carrier gas. Patent Document 3 has a configuration in which an inert gas heated to a high temperature is used as a carrier gas, and the inert gas used is reduced by circulating the inert gas in the organic solvent recovery system. It is disclosed.

  It is difficult to completely separate the organic solvent from the carrier gas only by the cooling and condensation operation, and the carrier gas discharged from the condensing and collecting apparatus contains a certain amount of unconcentrated organic solvent. Therefore, when the carrier gas containing the unconcentrated organic solvent is circulated as it is and the organic solvent is desorbed from the adsorbent, the regeneration of the adsorbent becomes insufficient, and the purification capacity for the gas to be treated is significantly reduced. .

  In order to solve these problems, Patent Document 3 includes a first adsorption / desorption processing device, a condensing / recovering device, and a second adsorption / desorption processing device on a circulation path through which the carrier gas is circulated. The first adsorption / desorption treatment apparatus includes a first adsorption / desorption element that adsorbs and desorbs an organic solvent contained in a gas to be treated. The condensation recovery device recovers an organic solvent as a condensate by condensing the organic solvent. The second adsorption / desorption treatment apparatus includes a second adsorption / desorption element that adsorbs and desorbs an organic solvent.

  The first adsorption / desorption treatment device further includes first temperature adjusting means for adjusting the temperature of the carrier gas discharged from the second adsorption / desorption treatment device in a high temperature state or a low temperature state to a high temperature state, The organic solvent is removed from the gas to be treated by bringing the gas to be treated and the carrier gas whose temperature is adjusted by the first temperature adjusting means into a high temperature state alternately in time with the first adsorption / desorption element. To a carrier gas in a high temperature state. The condensing and collecting apparatus condenses the organic solvent by adjusting the temperature of the carrier gas discharged from the first adsorption / desorption processing apparatus to a low temperature state.

  The second adsorption / desorption treatment device alternately adjusts the temperature of the carrier gas in a low temperature state including the non-condensed organic solvent discharged from the condensation recovery device to either a high temperature state or a low temperature state in time. A second temperature adjusting means for controlling the temperature of the carrier gas at a high temperature by the second temperature adjusting means and a low temperature at a temperature adjusted by the second temperature adjusting means. By bringing the carrier gas into contact with the second adsorption / desorption element alternately in time, the organic solvent is moved from the carrier gas in a low temperature state to the carrier gas in a high temperature state. In the initial stage of the desorption process for desorbing the organic solvent from the first adsorption / desorption element, the second temperature adjusting means is configured to remove the carrier gas in a low-temperature state containing the uncondensed organic solvent discharged from the condensation recovery device. In a later stage of the desorption process in which the temperature is adjusted to a high temperature state and the organic solvent is desorbed from the first adsorption / desorption element, a carrier gas in a low temperature state containing the uncondensed organic solvent discharged from the condensation recovery device is removed. Adjust the temperature to a low temperature.

  According to the above system, Patent Document 3 attempts to improve the purification capacity for the gas to be treated and the recovery efficiency of the organic solvent. In addition, even when an inert gas such as nitrogen gas is used as the carrier gas, an energy saving effect that can significantly suppress the amount of inert gas used is obtained.

Japanese Utility Model Publication No. 3-32924 JP-A-7-68127 Japanese Patent No. 5482776

  In the system disclosed in Patent Document 3, after the organic solvent is adsorbed and removed by the first adsorption / desorption element, the organic solvent moves to the carrier gas in the desorption process in which the organic solvent is desorbed from the first adsorption / desorption element. Is contained in the carrier gas discharged from the condensing and collecting apparatus and is adsorbed by the second adsorption / desorption element. Furthermore, in the first stage of the desorption process in which the organic solvent is desorbed from the first adsorption / desorption element, the organic solvent adsorbed by the second adsorption / desorption element moves to the carrier gas, and the temperature is adjusted to a high temperature to adjust the first adsorption / desorption element. Supplied to the desorption processing apparatus. Here, if the gas to be treated contains an organic solvent having a high boiling point, it is also included in the carrier gas discharged from the second adsorption / desorption element, and the organic solvent having a high boiling point is adjusted to a high temperature state. Even if it is supplied to the first adsorption / desorption treatment device, it is adsorbed by the first adsorption / desorption element. For this reason, the organic solvent having a high boiling point remains in the first adsorption / desorption element, lowers the adsorption performance, and reduces the recovery efficiency of the organic solvent.

  In addition, when an organic solvent having an unsaturated bond is included in the gas to be treated, an addition reaction may proceed in the pores of the adsorption element, which may increase the molecular weight and change to an organic substance having a high boiling point. As in the case of the organic solvent having a high boiling point, it remains in the first adsorption / desorption element to lower the adsorption performance and reduce the recovery efficiency of the organic solvent.

  Therefore, the present invention has been made in view of the above-described problems, and greatly reduces the adsorption performance of the adsorption / desorption element due to an organic substance that may remain in the adsorption / desorption element contained in the gas to be treated. It aims at providing the organic solvent recovery system which can implement | achieve resource saving by reducing.

  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. An organic solvent recovery system for cleaning and discharging a gas to be processed by separating the organic solvent from a gas to be processed containing an organic solvent and recovering the organic solvent separated from the gas to be processed by using a carrier gas. A first adsorption / desorption treatment device having a first adsorption / desorption element that adsorbs and desorbs an organic solvent in a circulation path through which the carrier gas circulates, a condensation recovery device that condenses the organic solvent and collects it as a condensate, and an organic solvent A second adsorbing / desorbing device having a second adsorbing / desorbing element for adsorbing and desorbing the gas, and a first temperature adjusting means for adjusting the temperature of the carrier gas introduced into the first adsorbing / desorbing device to a high temperature, and the second The second temperature adjusting means for adjusting the temperature of the carrier gas introduced into the adsorption / desorption device to a high temperature and the carrier gas discharged from the second adsorption / desorption treatment device are introduced to the first adsorption / desorption treatment device. And a bypass introduced into the condensing and collecting device without going through the first adsorption / desorption treatment device, the first adsorption / desorption treatment device including the introduced gas to be treated and the first gas The organic solvent is moved from the gas to be treated to a high temperature carrier gas by alternately contacting the first adsorption / desorption element with the high temperature carrier gas by the temperature adjusting means. The organic gas contained in the carrier gas is condensed by adjusting the temperature of the carrier gas discharged from the first adsorption / desorption treatment device to a low temperature state, and the second adsorption / desorption treatment device is discharged from the condensation recovery device and the first (2) A carrier gas introduced from a direct path not via the temperature control means, and a high-temperature carrier gas discharged from the condensation recovery device and introduced from a high-temperature path via the second temperature control means. Are alternately brought into contact with the second adsorption / desorption element to move the organic solvent from the carrier gas introduced from the direct path to a high-temperature carrier gas, thereby desorbing the organic solvent from the first adsorption / desorption element. Carrier gas is introduced into the second adsorption / desorption treatment device from the high temperature path in the first stage of the one adsorption element desorption process period, and from the direct path in the latter stage of the first adsorption / desorption element desorption process period, and The carrier gas discharged from the second adsorption / desorption processing device is introduced into the condensation recovery device from the bypass during a predetermined period after the first adsorption / desorption element removal processing period ends, and from the condensation recovery device. The organic solvent recovery system, wherein the discharged carrier gas is introduced into the second adsorption / desorption treatment apparatus from the high temperature path.
2. An organic solvent recovery system for cleaning and discharging a gas to be processed by separating the organic solvent from a gas to be processed containing an organic solvent and recovering the organic solvent separated from the gas to be processed by using a carrier gas. A first adsorption / desorption treatment device having a first adsorption / desorption element that adsorbs and desorbs an organic solvent in a circulation path through which the carrier gas circulates, a condensation recovery device that condenses the organic solvent and collects it as a condensate, and an organic solvent A second adsorbing / desorbing device having a second adsorbing / desorbing element for adsorbing and desorbing the gas, and a first temperature adjusting means for adjusting the temperature of the carrier gas introduced into the first adsorbing / desorbing device to a high temperature, and the second The second temperature adjusting means for adjusting the temperature of the carrier gas introduced into the adsorption / desorption device to a high temperature and the carrier gas discharged from the second adsorption / desorption treatment device are introduced to the first adsorption / desorption treatment device. And a bypass introduced into the condensing and collecting device without going through the first adsorption / desorption treatment device, the first adsorption / desorption treatment device including the introduced gas to be treated and the first gas The organic solvent is moved from the gas to be treated to a high temperature carrier gas by alternately contacting the first adsorption / desorption element with the high temperature carrier gas by the temperature adjusting means. The organic gas contained in the carrier gas is condensed by adjusting the temperature of the carrier gas discharged from the first adsorption / desorption treatment device to a low temperature state, and the second adsorption / desorption treatment device is discharged from the first adsorption / desorption treatment device. The carrier gas introduced from the direct path not passing through the second temperature control means and the high-temperature catalyst introduced from the high temperature path discharged from the condensation recovery apparatus and passed through the second temperature control means. By alternately contacting agas with the second adsorption / desorption element, the organic solvent is moved from the carrier gas introduced from the direct path to the high-temperature carrier gas, and the organic solvent is desorbed from the first adsorption / desorption element. Carrier gas is introduced into the second adsorption / desorption treatment apparatus from the high temperature path in the first stage of the first adsorption element desorption process period, and from the direct path in the latter stage of the first adsorption / desorption element desorption process period, The carrier gas discharged from the second adsorption / desorption treatment device is introduced into the condensation collection device from the bypass during a predetermined period after the first adsorption / desorption element removal treatment period ends, and the condensation collection is performed. An organic solvent recovery system, wherein the carrier gas discharged from the apparatus is introduced into the second adsorption / desorption processing apparatus from the high temperature path.
3. A third temperature adjusting means for adjusting the temperature of the carrier gas to a low temperature is provided on the direct path, and the carrier gas discharged from the first adsorption / desorption treatment device is in a later stage of the first adsorption / desorption element removal treatment period. 3. The organic solvent recovery system according to 2 above, wherein the temperature is lowered by the second temperature adjusting means and introduced into the second adsorption / desorption treatment apparatus from the direct path.
4). The carrier gas introduced from the direct path into the second adsorption / desorption device and the carrier gas introduced from the high-temperature path flow in a counterflow direction and contact the second adsorption / desorption element. The organic solvent collection | recovery system as described in any one of said 1-3.
5). 5. The organic solvent recovery system according to any one of 1 to 4, wherein the first adsorption / desorption element and / or the second adsorption / desorption element includes activated carbon fiber.
6). 6. The organic solvent recovery system according to any one of 1 to 5, wherein the carrier gas is an inert gas.
7). 7. The organic solvent recovery system according to any one of 1 to 6, wherein at least one of the organic solvents contained in the gas to be treated has a boiling point of 130 ° C. or higher.
8). 8. The organic solvent recovery system according to any one of 1 to 7, wherein at least one of the organic solvents contained in the gas to be treated has an unsaturated bond.

  Moreover, it is included in the category of this invention of the control method and control program which control the organic solvent collection | recovery system as described in any one of said 1-7.

  According to the above configuration of the present invention, the carrier gas discharged from the second adsorption / desorption processing apparatus is condensed and recovered without passing through the normal path introduced into the first adsorption / desorption processing apparatus and the first adsorption / desorption processing apparatus. It has a bypass that is introduced into the device. The carrier gas discharged from the second adsorption / desorption processing device is introduced from the bypass into the condensation recovery device and discharged from the condensation recovery device in a predetermined period after the first adsorption / desorption element removal processing period ends. The carrier gas is introduced into the second adsorption / desorption treatment apparatus from the high temperature path. Therefore, it is possible to prevent the organic solvent that may remain in the adsorption / desorption element contained in the carrier gas discharged from the second adsorption / desorption processing apparatus from being adsorbed by the first adsorption / desorption element. Therefore, according to the present invention, the decrease in adsorption performance of the adsorption / desorption element due to an organic substance that may remain in the adsorption / desorption element contained in the gas to be processed is greatly reduced, and the replacement frequency of the adsorption / desorption element is reduced. An organic solvent recovery system that can realize resource recycling can be provided.

1 is a system configuration diagram of an organic solvent recovery system in Embodiment 1 of the present invention. It is a system block diagram of the organic solvent collection | recovery system in Embodiment 2 of this invention. It is a system block diagram of the organic solvent collection | recovery system in Embodiment 3 of this invention. It is a time chart of the organic solvent collection | recovery system in 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 100A according to Embodiment 1 of the present invention. First, the configuration of the organic solvent recovery system 100A will be described with reference to FIG.

  The organic solvent recovery system 100A cleans and discharges the gas to be processed by separating the organic solvent from the gas to be processed containing the organic solvent, and collects the organic solvent separated from the gas to be processed using the carrier gas. System. As shown in FIG. 1, the organic solvent recovery system 100A includes a circulation path L1 composed of piping lines L4 to L7 arranged so that carrier gas circulates, and a first adsorption / desorption provided on the circulation path L1. The processing apparatus 10, the condensation collection | recovery apparatus 20, and the 2nd adsorption / desorption processing apparatus 30 are mainly provided. A circulation blower 40 is also provided.

  Organic solvents recovered by the organic solvent recovery system 100A include 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, ethyl formate, 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-trimethyl Examples include, but are not limited to, benzene, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, and dimethyl sulfoxide. Moreover, the organic solvent to collect | recover may be multiple types. The organic solvent recovery system 100A exhibits its effect especially when the organic solvent to be recovered has a high boiling point (for example, 130 ° C. or higher) or has an unsaturated bond. This will be described later.

  In the organic solvent recovery system 100A, various types of gases such as water vapor, heated air, and an inert gas heated to a high temperature can be used as the carrier gas. In particular, if an inert gas which is a gas not containing moisture is used, the organic solvent recovery system 100A can be configured more simply and safely. The circulation blower 40 is a blowing means for causing the carrier gas to flow through the circulation path L1. The circulation fan 40 sets the flow rate of the carrier gas appropriately. A plurality of circulation fans may be provided in the circulation path L1.

  The circulation path L1 is connected to an introduction line L0 for introducing the carrier gas from outside the circulation path L1. The introduction line L0 is used to introduce the carrier gas into the circulation path L1 when the organic solvent recovery system 100 is initially installed, or to replenish the carrier gas to the circulation path L1 as necessary during maintenance.

  The first adsorption / desorption treatment apparatus 10 includes a first adsorption / desorption tank A11, a first adsorption / desorption tank B12, and a first adsorption / desorption element desorption heater 13. The first adsorption / desorption element desorption heater 13 may be provided outside the first adsorption / desorption treatment apparatus 10.

  The first adsorption / desorption tank A11 includes a first adsorption / desorption element A14, and the first adsorption / desorption tank B12 includes a first adsorption / desorption element B15. 1st adsorption / desorption element A14 and 1st adsorption / desorption element B15 adsorb | suck the organic solvent contained in to-be-processed gas by making the to-be-processed gas introduced from the piping line L2 contact. Therefore, the first adsorption / desorption treatment apparatus 10 supplies (introduces) the gas to be treated to either the first adsorption / desorption tank A11 or the first adsorption / desorption tank B12, so that the organic solvent in the gas to be treated becomes the first. The first adsorption / desorption element A14 or the first adsorption / desorption element B15 is adsorbed and removed, and the clean gas is discharged from the first adsorption / desorption tank A11 and the first adsorption / desorption tank B12 to the outside through the piping line L3.

  The first adsorption / desorption element A14 or the first adsorption / desorption element B15 desorbs the adsorbed organic solvent by bringing a carrier gas brought into a high temperature state into contact with the first adsorption / desorption element desorption heater 13 described later. Therefore, in the first adsorption / desorption treatment apparatus 10, the organic solvent is fed into the first adsorption / desorption element A14 or the first by supplying the carrier gas in a high temperature state to the first adsorption / desorption tank A11 or the first adsorption / desorption tank B12. It is desorbed from the adsorption / desorption tank B12, moves to the carrier gas, and is discharged from the first adsorption / desorption tank A11 and the first adsorption / desorption tank B12.

  1st adsorption / desorption element A14 and 1st adsorption / desorption element B15 are comprised from the adsorbent containing any of granular activated carbon, activated carbon fiber, zeolite, silica gel, activated alumina, and a porous organic compound. Preferably, the adsorbent is composed of activated carbon fibers. Activated carbon fiber has a very large outer surface area due to its fiber structure, and since micropores are directly open on the fiber surface, it has high gas contact efficiency and can exhibit higher adsorption / desorption efficiency than other adsorbents. .

  The 1st adsorption / desorption processing apparatus 10 is connected to the piping lines L2 and L3, respectively. The piping line L2 is a piping line for supplying a gas to be treated containing an organic solvent to the first adsorption / desorption tank A11 and the first adsorption / desorption tank B12, and the first adsorption / desorption tank A11 and the first adsorption / desorption by a valve. The connection state and non-connection state with respect to the tank B12 are switched. The piping line L3 is a piping line for discharging clean gas from the first adsorption / desorption tank A11 and the first adsorption / desorption tank B12, and is connected to the first adsorption / desorption tank A11 and the first adsorption / desorption tank B12 by a valve. Switch to disconnected state.

  Moreover, the 1st adsorption / desorption processing apparatus 10 is connected to the piping lines L4 and L5, respectively. The piping line L4 is a piping line for supplying the carrier gas to the first adsorption / desorption tank A11 and the first adsorption / desorption tank B12 via the first adsorption / desorption element desorption heater 13, and the first adsorption / desorption is performed by a valve. The connection state and the non-connection state for the tank A11 and the first adsorption / desorption tank B12 are switched. The piping line L5 is a piping line for discharging the carrier gas from the first adsorption / desorption tank A11 and the first adsorption / desorption tank B12, and is connected to the first adsorption / desorption tank A11 and the first adsorption / desorption tank B12 by a valve. Switch to disconnected state. In this embodiment, “discharge from the first adsorption / desorption tank A11” and “discharge from the first adsorption / desorption element A14” are used interchangeably. Similarly, “discharge from the first adsorption / desorption tank B12” and “discharge from the first adsorption / desorption element B15” are used in the same meaning.

  In each of the first adsorption / desorption tank A11 and the first adsorption / desorption tank B12, the temperature is adjusted by the gas to be treated and the first adsorption / desorption element desorption heater 13 by operating the opening / closing of the valve described above. In this state, the carrier gas is alternately supplied over time. Thereby, 1st adsorption / desorption tank A11 and 1st adsorption / desorption tank B12 function as an adsorption tank and a desorption tank alternately in time. Accordingly, the organic solvent moves from the gas to be treated to the carrier gas. Specifically, when the first adsorption / desorption tank A11 functions as an adsorption tank, the first adsorption / desorption tank B12 functions as a desorption tank, and the first adsorption / desorption tank A11 functions as a desorption tank. When it is, the 1st adsorption / desorption tank B12 functions as an adsorption tank.

  Here, the piping line L2 is connected to a processing tank functioning as an adsorption tank in the first adsorption / desorption tank A11 or the first adsorption / desorption tank B12, and supplies a gas to be processed to the processing tank. The piping line L3 is connected to a processing tank functioning as an adsorption tank in the first adsorption / desorption tank A11 or the first adsorption / desorption tank B12, and discharges clean gas from the processing tank. The piping line L4 is connected to a processing tank functioning as a desorption tank in the first adsorption / desorption tank A11 or the first adsorption / desorption tank B12, and supplies a carrier gas to the processing tank. The piping line L5 is connected to a processing tank functioning as a desorption tank in the first adsorption / desorption tank A11 or the first adsorption / desorption tank B12, and discharges the carrier gas from the processing tank.

  The condensation recovery device 20 includes a capacitor 21 and a recovery tank 22. The capacitor 21 is a device that cools and condenses the organic solvent contained in the carrier gas by adjusting the temperature of the carrier gas to a low temperature state. The recovery tank 22 is a container that stores the organic solvent liquefied by the capacitor 21 as a condensed liquid. The carrier gas remaining without being aggregated in the condensing and collecting apparatus 20 is discharged from the piping line L6.

  The capacitor 21 is maintained at a constant low temperature, and the carrier gas discharged from the capacitor 21 contains an organic solvent having a saturated vapor concentration at the set temperature. That is, the condensation recovery apparatus 20 recovers the difference between the concentration of the organic solvent in the carrier gas supplied to the capacitor 21 and the concentration of the organic solvent in the carrier gas discharged from the capacitor 21.

  The condensation recovery apparatus 20 is connected to the piping lines L5 and L6. The piping line L <b> 6 is a piping line that supplies the carrier gas discharged from the condensation recovery device 20 to the second adsorption / desorption processing device 30. The condensing and collecting apparatus 20 is connected to a discharge line L9 for discharging the organic solvent condensate stored in the collecting tank 22 to the outside.

  The second adsorption / desorption treatment device 30 includes a second adsorption / desorption tank 31 having a second adsorption / desorption element 32 and a second adsorption / desorption element desorption heater 33, and adsorbs and adsorbs an organic solvent contained in the carrier gas. An apparatus for desorbing an organic solvent with a high-temperature carrier gas. The second adsorption / desorption element desorption heater 33 is a device that adjusts the temperature of the carrier gas discharged from the condensing and collecting apparatus 20 to a high temperature state and supplies the carrier gas to the second adsorption / desorption tank 31. The second adsorption / desorption element desorption heater 33 may be provided outside the second adsorption / desorption treatment device 30. In the present embodiment, “discharge from the second adsorption / desorption tank 31”, “discharge from the second adsorption / desorption element 32”, and “discharge from the second adsorption / desorption treatment device 30” are used in the same meaning.

  The second adsorption / desorption treatment device 30 directly introduces the carrier gas discharged from the condensation / recovery device 20 into the second adsorption / desorption tank 31 and causes the second adsorption / desorption element 32 to adsorb the organic solvent contained in the carrier gas. The carrier gas having a reduced concentration is discharged from the second adsorption / desorption tank 31. In addition, a carrier gas heated to a high temperature by the second adsorption / desorption element desorption heater 33 is introduced into the second adsorption / desorption tank 31 to desorb the organic solvent from the second adsorption / desorption element 32, and the carrier gas containing the organic solvent is removed. 2 Drain from the adsorption / desorption tank 21.

  The second adsorption / desorption element 32 is composed of an adsorbent containing any of granular activated carbon, activated carbon fiber, zeolite, silica gel, activated alumina, and a porous organic compound. Preferably, the adsorbent is composed of activated carbon fibers. Activated carbon fiber has a very large outer surface area due to its fiber structure, and since micropores are directly open on the fiber surface, it has high contact efficiency with gas and exhibits higher adsorption / desorption efficiency than other adsorbents. .

  Piping lines L6 and L7 are connected to the second adsorption / desorption processing device 30, respectively. The pipe line L6 includes a branch point 50, and a path (high temperature path) for supplying the carrier gas discharged from the condensing and collecting apparatus 20 to the second adsorption / desorption tank 31 via the second adsorption / desorption element desorption heater 33; The second branch is branched into a path (direct path) that is supplied directly to the second adsorption / desorption tank 31 without passing through the second adsorption / desorption element desorption heater 33. Of these paths, the path through which the carrier gas passes is switched by a valve. The piping line L7 is a piping line for discharging the carrier gas from the second adsorption / desorption tank, and a connection state and a non-connection state with respect to the second adsorption / desorption tank 31 are switched by a valve.

  Here, in the second adsorption / desorption treatment device 30, the high-temperature carrier gas introduced through the second adsorption / desorption element desorption heater 33 flows through the second adsorption / desorption element 32 in the second adsorption / desorption tank 31. The direction in which the carrier gas in the low temperature state introduced directly from the condensing and collecting apparatus 20 needs to flow is the counterflow direction (reverse direction) in which the second adsorption / desorption element 32 flows. For this purpose, the valves of the piping line L6 and the piping line L7 are operated.

  Here, in the second adsorption / desorption tank 31, the direction in which the high-temperature carrier gas introduced through the second adsorption / desorption element desorption heater 33 flows through the second adsorption / desorption element 32 is from the condensation recovery device 20. When the carrier gas in the low temperature state directly introduced is in the co-current direction (the same direction) in which the second adsorption / desorption element 32 flows, the organic solvent having a high boiling point or the organic solvent having a high molecular weight by addition reaction is used. The two adsorbing / desorbing elements 32 may not be desorbed and remain in the inner layer of the second adsorbing / desorbing element 32, thereby reducing the adsorption performance.

  Therefore, in the present embodiment, the valves of the piping line L6 and the piping line L7 are operated so that the high temperature carrier gas flows through the second adsorption / desorption element 32 and the low temperature carrier gas is the second adsorption / desorption element. The direction through which the gas flows 32 is defined as a countercurrent direction. As a result, an organic solvent having a high boiling point or an organic substance having a high molecular weight by addition reaction is efficiently desorbed from the second adsorption / desorption element 32, and the adsorption performance is maintained without remaining in the inner layer of the second adsorption / desorption element 32.

  In the organic solvent recovery system 100A, the second adsorption / desorption processing device 33 is arranged such that the carrier gas in the high temperature state flows through the second adsorption / desorption element 32, and the carrier gas in the low temperature state passes through the second adsorption / desorption element 32. The configuration may be a parallel flow direction of the flow direction.

  The carrier gas discharged from the second adsorption / desorption processing device 30 is supplied to the circulation fan 40. The circulation blower 40 is a device for circulating the carrier gas through the circulation system L1.

  The carrier gas discharged from the circulation blower 40 passes through the piping line L4 (normal path) when supplied to the first adsorption / desorption processing device 10, and the piping line L8 (when supplied directly to the condensation recovery device 20). Via). The piping line L8 is a bypass for introducing the carrier gas discharged from the second adsorption / desorption processing device and sent out by the circulation blower 40 to the condensing and collecting device without passing through the first adsorption / desorption processing device 100. Whether the carrier gas discharged from the circulation blower 40 is supplied to the first adsorption / desorption treatment device 10 or the condensation recovery device 20 is operated by a valve. The timing for supplying the carrier gas to the condensing and collecting apparatus 20 will be described later.

  The first adsorption / desorption element desorption heater 13 is a device that adjusts the temperature of the carrier gas supplied to the first adsorption / desorption treatment device 10 to a high temperature state. The first adsorption / desorption element desorption heater 13 is a carrier gas supplied to the first adsorption / desorption tank A11 and the first adsorption / desorption tank B12 so that the first adsorption / desorption elements A14, B15 are maintained at a predetermined desorption temperature. Heat. The first adsorption / desorption element desorption heater 13 may be configured to be incorporated in the first adsorption / desorption tank A11 and the first adsorption / desorption tank B12.

  FIG. 4 is a time chart showing temporal switching between the adsorption process and the desorption process in the pair of first adsorption / desorption elements A14, B15 and the second adsorption / desorption element 32 in the organic solvent recovery system 100A shown in FIG. In FIG. 4, t0 to t6 indicate time, and it is assumed that the time has passed toward the right. Below, with reference to FIG. 1 and FIG. 4, the detail of the process of the to-be-processed gas in the organic-solvent collection | recovery system 100A of this Embodiment is demonstrated.

  The organic solvent recovery system 100A shown in FIG. 1 is an organic solvent that is a gas to be treated by repeatedly executing one cycle shown in FIG. 4 (between t0 and t6 shown in FIG. 4) as a unit period. Processing of the contained gas is performed continuously.

  In the first half of the above cycle (between t0 and t3 shown in FIG. 4), the first adsorption / desorption treatment apparatus 10 performs the adsorption treatment by the first adsorption element 14A in the first treatment tank A11, and in parallel therewith. The first treatment tank B12 performs the desorption process by the first adsorption / desorption element B15 (the first adsorption / desorption element desorption process period between t0 and t2 shown in FIG. 4) and does not process anything thereafter. A standby process is performed (a predetermined period after the first adsorption / desorption element desorption process period ends between t2 and t3 shown in FIG. 4).

  In the first stage of the desorption process by the first adsorption / desorption element B15 (between t0 and t1 shown in FIG. 4), the second adsorption / desorption processing apparatus 30 performs the second desorption process by the second adsorption / desorption element 32. Further, in the latter stage of the desorption process by the first adsorption / desorption element B15 (between times t1 and t2 shown in FIG. 4), the second adsorption / desorption processing apparatus 30 performs the adsorption process by the second adsorption / desorption element 32.

  Further, in the standby step (between times t2 and t3 shown in FIG. 4) after the desorption process by the first adsorption / desorption element B15 is completed, both the gas to be treated and the carrier gas are contained in the first adsorption / desorption element B15. On the other hand, the second adsorption / desorption processing device 30 performs the first desorption process by the second adsorption / desorption element 32 without being passed. The carrier gas discharged from the circulation blower 40 during this period is directly introduced into the condensing and collecting apparatus 20 through the piping line L8 without passing through the first adsorption / desorption processing apparatus 10.

  In the second half of the above cycle (between t3 and t6 shown in FIG. 4), the first adsorption / desorption treatment apparatus 10 performs the adsorption treatment by the first adsorption element B15 in the first treatment tank B12. In parallel, 1st process tank A11 implements the desorption process by 1st adsorption / desorption element A14, and waits after that (standby process). The operation of the second adsorption / desorption processing device 30 in the latter half of the one cycle is the same as the first half of the one cycle, as shown in FIG.

  Next, the recovery of the organic solvent and the flow of the carrier gas in the organic solvent recovery system 100A according to the embodiment of the present invention will be described in detail with reference to FIGS. The following description is based on the state in which the first adsorption / desorption tank A11 of the first adsorption / desorption treatment apparatus 10 functions as an adsorption tank and the first adsorption / desorption tank B12 functions as a desorption tank. The same applies to the case where the desorption tank is replaced. In the following description, it is assumed that the organic solvent contained in the gas to be treated contains an organic solvent having a high boiling point.

  In the organic solvent recovery system 100A, in the first stage of the desorption process period by the first adsorption / desorption element B15 (that is, between t0 and t1 shown in FIG. 4), the uncondensed organic solvent discharged from the condensation recovery device 20 is removed. The low-temperature carrier gas is introduced into the second adsorption / desorption processing device heater 33 and heated to a high temperature state, and is supplied to the second adsorption / desorption tank 31 of the second adsorption / desorption treatment device 30 to be second adsorbed / desorbed. Contact element 32.

  Thereby, when there is an organic solvent adsorbed by the second adsorption / desorption element 32, it is desorbed from the second adsorption / desorption element 32 by the high-temperature carrier gas (second desorption process), and the second adsorption / desorption tank 31 is removed. And the concentration of the organic solvent in the carrier gas is supplied to the circulation fan 40 in an increased state. The carrier gas discharged from the circulation blower 40 is adjusted to a high temperature state by the first adsorption / desorption treatment device heater 13 and supplied to the first adsorption / desorption element B15 of the first adsorption / desorption treatment device 10. As a result, the organic solvent adsorbed on the first adsorption / desorption element B15 is desorbed and introduced into the condensing and collecting apparatus 20 in a state where the concentration of the organic solvent in the carrier gas is further increased. Here, the organic solvent having a high boiling point contained in the organic solvent adsorbed on the first adsorption / desorption element B15 is also desorbed from the first adsorption / desorption element B15. As will be described later, since most of the organic solvent is desorbed and collected in the first desorption process in the second adsorption / desorption element 32, the organic solvent is the first in the second desorption process in the second adsorption / desorption element 32. Almost no supply to the adsorption / desorption element 15B.

  Part of the organic solvent contained in the carrier gas discharged from the first adsorption / desorption element B15 is condensed and recovered by the condenser 21 of the condensation recovery device 20, and the unrecovered (uncondensed) organic solvent is discharged from the capacitor 21. And is adsorbed by the second adsorption / desorption element 32 of the second adsorption / desorption treatment device 30 (adsorption treatment).

  Next, in the latter stage of the desorption process period by the first adsorption / desorption element B15 (that is, between t1 and t2 shown in FIG. 4), the low-temperature state containing the uncondensed organic solvent discharged from the condensation recovery apparatus 20 The carrier gas in the first adsorption / desorption element B15 is directly absorbed in the second adsorption so as to be in a counter-current direction with the carrier gas introduced in the first stage of the desorption process period (between t0 and t1 shown in FIG. 2). It is supplied to the second adsorption / desorption tank 31 of the desorption treatment apparatus 30 and contacts the second adsorption / desorption element 32.

  As a result, the organic solvent contained in the carrier gas is adsorbed and removed by the second adsorption / desorption element 32, and the concentration of the organic solvent in the carrier gas discharged from the second adsorption / desorption tank 31 is gradually reduced. The Along with this, the concentration of the organic solvent contained in the carrier gas supplied to the first adsorption / desorption element B15 of the first adsorption / desorption treatment apparatus 10 is also gradually reduced, and the regeneration of the first adsorption / desorption element B15 is further promoted. Will be. Here, the organic solvent having a high boiling point contained in the carrier gas discharged from the condensation recovery apparatus 20 is also adsorbed by the second adsorption / desorption element 32.

  Next, in a standby step (between times t2 and t3 shown in the drawing) after the desorption process of the first adsorption / desorption element B15 is completed, the first adsorption / desorption element B15 is supplied with either the gas to be treated or the carrier gas. Does not flow. During the standby process, the carrier gas discharged from the second adsorption / desorption processing device 30 and sent out from the circulation blower 40 is directly supplied to the condensing and collecting device 20 without passing through the first adsorption / desorption processing device 10. The carrier gas discharged from the condensing and collecting device 20 is adjusted to a high temperature by the second heater 33 and supplied to the second adsorption / desorption device 32 of the second adsorption / desorption treatment device 30. Most of the organic solvent including the organic solvent having a high boiling point adsorbed on the two adsorption / desorption elements 32 is desorbed (first desorption process). The organic solvent containing the organic solvent having a high boiling point desorbed from the second adsorption / desorption element 32 in this way is directly supplied to the condensing and collecting apparatus 20 and recovered as a condensate. Therefore, the organic solvent containing an organic solvent having a high boiling point is hardly supplied to the first adsorption / desorption element A14 in the first stage (between t3 and t4 shown in FIG. 4) of the subsequent desorption process period of the first adsorption / desorption element A14. And the fall of the adsorption | suction performance of 1st adsorption / desorption element A14 can be suppressed.

  Here, the organic solvent having a high boiling point is adsorbed by the first adsorption / desorption element when supplied to the first adsorption / desorption treatment apparatus even if the organic solvent having a high boiling point is adjusted to a high temperature state, and the organic solvent having a high boiling point is absorbed by the first adsorption / desorption element. It remains to lower the adsorption performance and reduce the recovery efficiency of the organic solvent. In addition, if the gas to be treated contains an organic solvent having an unsaturated bond, an addition reaction may proceed in the pores of the adsorption element, which may increase the molecular weight to change to an organic substance having a high boiling point. As in the case of a high organic solvent, it remains in the first adsorption / desorption element to lower the adsorption performance and reduce the recovery efficiency of the organic solvent.

  However, in the organic solvent recovery system 100A, in particular, the piping line L8 is provided, and the carrier gas discharged from the second adsorption / desorption processing device 30 is introduced into the condensation recovery device 20 from the piping line L8 during the standby process, and The carrier gas discharged from the condensing and collecting apparatus 20 is heated to a high temperature by the second adsorption / desorption element desorption heater 33 and introduced into the second adsorption / desorption treatment apparatus.

  Therefore, even if the gas to be treated contains an organic solvent having a high boiling point or an organic solvent having an unsaturated bond is contained in the gas to be treated, the organic solvent recovery system 100A discharges from the second adsorption / desorption treatment device 30. It is possible to prevent the organic solvent that may remain in the first adsorption / desorption element contained in the carrier gas from being adsorbed by the first adsorption / desorption element. Therefore, it is possible to save resources by greatly reducing the adsorption performance of the adsorption / desorption element due to organic substances that may remain in the adsorption / desorption element contained in the gas to be treated, and by reducing the frequency of replacement of the adsorption / desorption element. .

(Embodiment 2)
FIG. 2 is a configuration diagram of an organic solvent recovery system 100B according to Embodiment 2 of the present invention. The organic solvent recovery system 100B basically has the same configuration as the organic solvent recovery system 100A. However, in the organic solvent recovery system 100A, the piping line L6 for introducing the carrier gas discharged from the condensation recovery device 20 into the second adsorption / desorption processing device 30 has the branch point 50. However, the organic solvent recovery system In 100B, the piping line L6 does not have the branch point 50. Instead, the piping line L5 has a branch point 50.

  In the organic solvent recovery system 100B, the piping line L5 has a branch point 50, and a path (direct path) for supplying the carrier gas discharged from the first adsorption / desorption treatment apparatus 10 directly to the second adsorption / desorption tank 31; , Branching off to the supply path to the condensing recovery device 20. Furthermore, the piping line L6 is a path (high temperature path) for supplying the carrier gas to the second adsorption / desorption tank 31 through the second adsorption / desorption element desorption heater 33 in a high temperature state. Except for these configurations, the organic solvent recovery system 100A is the same.

  Hereinafter, the processing in the organic solvent recovery system 100B will be described only for parts different from the organic solvent recovery system 100A. In addition, although the following description is based on the state where the 1st adsorption / desorption tank A11 of the 1st adsorption / desorption processing apparatus 10 functions as an adsorption tank, and the 1st adsorption / desorption tank B12 functions as a desorption tank similarly to the above. The same applies when the adsorption tank and the desorption tank are interchanged.

  In the organic solvent recovery system 100B, the latter stage of the desorption process period of the first desorption element B15 accommodated in the first adsorption / desorption tank B12 of the first adsorption / desorption processing apparatus 10 (that is, between t1 and t2 shown in FIG. 4). In FIG. 4, the carrier gas containing the organic solvent discharged from the first adsorption / desorption tank B12 does not pass through the condensing / recovering device 20, and is the first stage of the desorption process period of the first adsorption / desorption element B15 (between t0 and t1 shown in FIG. 4). ) Is directly supplied to and absorbed by the second adsorption / desorption tank 31 of the second adsorption / desorption treatment device 30 from the counterflow direction, and contacts the second adsorption / desorption element 32.

  The condenser 21 of the condensing and collecting apparatus 20 contains a cooled and condensed organic solvent. A part of the organic solvent is re-volatilized and supplied to the second adsorption / desorption processing apparatus 30 during the adsorption process. Therefore, in the organic solvent recovery system 100B, the piping line L5 is branched between the first adsorption / desorption processing device 10 and the condensation recovery device 20, and in the adsorption process of the second adsorption / desorption element 32, the condensation recovery device 20 and the second The carrier gas is supplied to the second adsorption / desorption element 32 of the second adsorption / desorption tank 31 without going through the heater 40 for the adsorption / desorption element. Thereby, the concentration of the organic solvent contained in the carrier gas can be further reduced, and the regeneration of the first adsorption / desorption element B15 can be further promoted. Thereby, in the second half of one cycle, the purification capacity of the first adsorption / desorption element B15 of the first adsorption / desorption treatment apparatus 10 for the gas to be treated is improved, and the recovery efficiency of the organic solvent is also improved.

  Further, in the organic solvent recovery system 100B, an organic substance having a high boiling point that is desorbed from the first adsorption / desorption element B15 in the latter stage (between t1 and t2 shown in FIG. 4) of the desorption process period of the first adsorption / desorption element B15. Is directly supplied to the second adsorbing / desorbing element 32 and adsorbed, but in the waiting step (between times t2 and t3 shown in the drawing) after the subsequent desorbing process of the first adsorbing / desorbing element B15 is completed. Carrier gas adjusted to a high temperature by the second adsorption / desorption element heater 33 is supplied to the adsorption / desorption element 32, and most of the organic substance having a high boiling point adsorbed by the second adsorption / desorption element 32 is desorbed. The desorbed organic substance having a high boiling point is directly supplied to the condensing and collecting apparatus 20 through the piping line L8 and recovered as a condensed liquid. Therefore, the organic substance having a high boiling point is hardly supplied to the first adsorption / desorption element A14 in the first stage (between t3 and t4 shown in FIG. 4) of the subsequent desorption process period of the first adsorption / desorption element A14. A decrease in adsorption performance of the element A14 can be suppressed.

(Embodiment 3)
FIG. 3 is a conceptual diagram of an organic solvent recovery system 100C according to Embodiment 3 of the present invention. In addition to the configuration of the organic solvent recovery system 100B, the organic solvent recovery system 100C has a path for directly supplying the carrier gas discharged from the first adsorption / desorption treatment device 10 after branching of the piping line L5 to the second adsorption / desorption tank 31. The second adsorption / desorption element cooler 60 is provided. The rest is the same as the organic solvent recovery system 100B.

  Hereinafter, regarding the processing in the organic solvent recovery system 100C, only the parts different from the description of the organic solvent recovery system 100A and the description of the organic solvent recovery system 100B will be described. In addition, although the following description is based on the state where the 1st adsorption / desorption tank A11 of the 1st adsorption / desorption processing apparatus 10 functions as an adsorption tank, and the 1st adsorption / desorption tank B12 functions as a desorption tank similarly to the above. The same applies when the adsorption tank and the desorption tank are interchanged.

  In the organic solvent recovery system 100C, the carrier gas containing the organic solvent discharged from the first adsorption / desorption tank B12 is in the latter stage (between t1 and t2 shown in FIG. 4) of the desorption process period of the first adsorption / desorption element B15. The direction of the direction supplied to the first stage (between t0 and t1 shown in FIG. 4) of the desorption process period of the first adsorption / desorption element B15 via the second adsorption / desorption element cooler 60 without passing through the condensing / recovery device 20. It is supplied directly to the second adsorption / desorption tank 31 from the flow direction and contacts the second adsorption / desorption element 32.

  In the organic solvent recovery system 100C, the temperature of the carrier gas brought into contact with the second adsorption / desorption element 32 is adjusted to a lower temperature by the cooler 60 for the second adsorption / desorption element. Therefore, the organic solvent can be more efficiently adsorbed by the second adsorption / desorption element 32, and the concentration of the organic solvent contained in the carrier gas discharged from the second adsorption / desorption tank 31 can be further reduced. Therefore, regeneration of the first adsorption / desorption element B15 is further promoted. Thereby, in the second half of one cycle, the purification capacity of the first adsorption / desorption element B15 of the first adsorption / desorption treatment apparatus 10 for the gas to be treated is improved, and the recovery efficiency of the organic solvent is also improved.

Using the organic solvent recovery systems 100A, 100B and 100C described above, the organic solvent was recovered as follows.
<Example 1>
In Example 1, an organic solvent recovery system 100A was used. As a gas to be treated by the organic solvent recovery system 100A, a gas at 35 ° C. containing 2000 ppm ethyl acetate having a boiling point of 70 ° C. and N-methylpyrrolidone having a boiling point of 202 ° C. was used. Further, in the organic solvent recovery system 100A, nitrogen gas at 120 ° C. is used as a carrier gas, activated carbon fibers having a specific surface area of 1500 m ² / g are used as the first adsorption / desorption elements A14, B15, and the second adsorption / desorption element. 32, an activated carbon fiber having a specific surface area of 2000 m ² / g was used.

While the gas to be treated is supplied to one of the first adsorption / desorption elements at an air flow rate of 7 Nm ³ / min, the carrier gas is supplied to the other first adsorption / desorption element at 1.5 Nm ³ / min. Desorption treatment was performed. The carrier gas temperature in the condenser 21 of the condensing and collecting apparatus 20 was set to 10 ° C. The carrier gas temperature in the second adsorption / desorption element desorption heater 33 was set to 120 ° C. The carrier gas temperature in the first adsorption / desorption element desorption heater 13 was set to 120 ° C.

<Example 2>
In Example 2, the organic solvent recovery system 100B was used. As a gas to be treated by the organic solvent recovery system 100B, a gas at 35 ° C. containing 2000 ppm of ethyl acetate having a boiling point of 70 ° C. and N-methylpyrrolidone having a boiling point of 202 ° C. was used. Further, in the organic solvent recovery system 100B, nitrogen gas at 120 ° C. is used as the carrier gas, activated carbon fibers having a specific surface area of 1500 m ² / g are used as the first adsorption / desorption elements A14, B15, and the second adsorption / desorption element. 32, an activated carbon fiber having a specific surface area of 2000 m ² / g was used.

While the gas to be treated is supplied to one of the first adsorption / desorption elements at an air flow rate of 7 Nm ³ / min, the carrier gas is supplied to the other first adsorption / desorption element at 1.5 Nm ³ / min. Desorption treatment was performed. The carrier gas temperature in the condenser 21 of the condensing and collecting apparatus 20 was set to 10 ° C. In addition, the carrier gas temperature in the second heater 33 was set to be 120 ° C. The carrier gas temperature in the first adsorption / desorption element desorption heater 13 was set to 120 ° C.

<Example 3>
In Example 3, an organic solvent recovery system 100C was used. As a gas to be treated in the organic solvent recovery system 100C, a gas at 35 ° C. containing 2000 ppm of ethyl acetate having a boiling point of 70 ° C. and N-methylpyrrolidone having a boiling point of 202 ° C. was used. In the organic solvent recovery system 100C, nitrogen gas at 120 ° C. is used as the carrier gas, activated carbon fibers having a specific surface area of 1500 m ² / g are used as the first adsorption / desorption elements A14 and B15, and the second adsorption / desorption element 32, an activated carbon fiber having a specific surface area of 2000 m ² / g was used.

While the gas to be treated is supplied to one of the first adsorption / desorption elements at an air flow rate of 7 Nm ³ / min, the carrier gas is supplied to the other first adsorption / desorption element at 1.5 Nm ³ / min. Desorption treatment was performed. The carrier gas temperature in the condenser 21 of the condensing and collecting apparatus 20 was set to 10 ° C. The same operation as in Example 2 was performed except that the carrier gas temperature in the second adsorption / desorption element cooler 60 was set to 20 ° C. In addition, the carrier gas temperature in the second heater 33 was set to be 120 ° C. The carrier gas temperature in the first adsorption / desorption element desorption heater 13 was set to 120 ° C.

<Comparative Example 1>
In Comparative Example 1, an organic solvent recovery system having a configuration in which the piping line L8 for directly supplying the carrier gas to the condensation recovery processing apparatus without the first adsorption / desorption processing apparatus 10 is eliminated in the organic solvent recovery system 100A. Then, the standby process shown in FIG. 4 is omitted. Except for these, the same operation as in Example 1 was performed.

  The organic solvent removal efficiencies of Examples 1 to 3 and Comparative Example 1 are shown in Table 1.

  As can be seen from Table 1, in Examples 1 to 3, reduction in recovery efficiency due to N-methylpyrrolidone when the number of cycles was repeated as compared with Comparative Example 1 was suppressed. That is, it has been experimentally confirmed that by using the organic solvent recovery system of the present invention, it is possible to significantly reduce the decrease in adsorption performance of the adsorption / desorption element and maintain high recovery efficiency of the organic solvent for a long period of time.

  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 for a system for recovering an organic solvent from a gas to be treated containing an organic solvent discharged from various factories or research facilities, for example.

10 1st adsorption / desorption processing apparatus 11 1st adsorption / desorption tank A
12 First adsorption / desorption tank B
13 1st adsorption / desorption element desorption heater (1st temperature control means)
14 First adsorption / desorption element A
15 Second adsorption / desorption element B
20 Condensation recovery device 21 Capacitor 22 Recovery tank 30 Second adsorption / desorption treatment device 31 Second adsorption / desorption tank 32 Second adsorption / desorption element 33 Second adsorption / desorption element desorption heater (second temperature adjusting means)
40 Circulating fan 50 Branch point 60 Cooler for adsorbing / desorbing second element (third temperature adjusting means)
70 Processed gas blowers 100A to 100B Organic solvent recovery system L0 Introduction line L1 Circulation path L4 Piping line (normal path)
L8 Piping line (Bypass)
L9 discharge line

Claims (8)

An organic solvent recovery system for cleaning and discharging a gas to be processed by separating the organic solvent from a gas to be processed containing an organic solvent and recovering the organic solvent separated from the gas to be processed by using a carrier gas. ,
A first adsorption / desorption treatment device having a first adsorption / desorption element that adsorbs and desorbs an organic solvent in a circulation path through which the carrier gas circulates, a condensation recovery device that condenses the organic solvent and collects it as a condensate, and an organic solvent. A second adsorption / desorption treatment device having a second adsorption / desorption element that adsorbs and desorbs,
First temperature adjusting means for adjusting the temperature of the carrier gas introduced into the first adsorption / desorption device to a high temperature;
Second temperature adjusting means for adjusting the temperature of the carrier gas introduced into the second adsorption / desorption device to a high temperature;
The carrier gas discharged from the second adsorption / desorption processing device is a normal path through which the carrier gas is introduced into the first adsorption / desorption treatment device, and a bypass that is introduced into the condensation recovery device without going through the first adsorption / desorption treatment device. And comprising
The first adsorption / desorption treatment apparatus treats an organic solvent by bringing the introduced gas to be treated and the carrier gas heated to a high temperature by the first temperature adjusting means into contact with the first adsorption / desorption element alternately. Move from the gas to a heated carrier gas,
The condensation recovery device condenses the organic solvent contained in the carrier gas by adjusting the temperature of the carrier gas discharged from the first adsorption / desorption treatment device to a low temperature state,
The second adsorption / desorption treatment device is discharged from the condensation recovery device and introduced from a direct path not through the second temperature adjustment means, and is discharged from the condensation recovery device and passes through the second temperature adjustment means. The organic solvent is moved from the carrier gas introduced from the direct path to the hot carrier gas by alternately contacting the second adsorption / desorption element with the high temperature carrier gas introduced from the high temperature path,
The first adsorption element desorption treatment period for desorbing the organic solvent from the first adsorption / desorption element is from the high-temperature path in the first stage, and the second adsorption stage from the direct path in the latter stage of the first adsorption / desorption element desorption process period. 2 carrier gas is introduced into the adsorption / desorption treatment device, and
In a predetermined period after the end of the first adsorption / desorption element desorption process period, the carrier gas discharged from the second adsorption / desorption processing apparatus is introduced into the condensation recovery apparatus from the bypass and discharged from the condensation recovery apparatus. The carrier gas is introduced into the second adsorption / desorption treatment apparatus from the high temperature path, and is an organic solvent recovery system. An organic solvent recovery system for cleaning and discharging a gas to be processed by separating the organic solvent from a gas to be processed containing an organic solvent and recovering the organic solvent separated from the gas to be processed by using a carrier gas. ,
A first adsorption / desorption treatment device having a first adsorption / desorption element that adsorbs and desorbs an organic solvent in a circulation path through which the carrier gas circulates, a condensation recovery device that condenses the organic solvent and collects it as a condensate, and an organic solvent. A second adsorption / desorption treatment device having a second adsorption / desorption element that adsorbs and desorbs,
First temperature adjusting means for adjusting the temperature of the carrier gas introduced into the first adsorption / desorption device to a high temperature;
Second temperature adjusting means for adjusting the temperature of the carrier gas introduced into the second adsorption / desorption device to a high temperature;
The carrier gas discharged from the second adsorption / desorption processing device is a normal path through which the carrier gas is introduced into the first adsorption / desorption treatment device, and a bypass that is introduced into the condensation recovery device without going through the first adsorption / desorption treatment device. And comprising
The first adsorption / desorption treatment apparatus treats an organic solvent by bringing the introduced gas to be treated and the carrier gas heated to a high temperature by the first temperature adjusting means into contact with the first adsorption / desorption element alternately. Move from the gas to a heated carrier gas,
The condensation recovery device condenses the organic solvent contained in the carrier gas by adjusting the temperature of the carrier gas discharged from the first adsorption / desorption treatment device to a low temperature state,
The second adsorption / desorption processing device is discharged from the first adsorption / desorption processing device and introduced from a direct path not through the second temperature adjusting means, and is discharged from the condensation recovery device and is subjected to the second temperature adjustment. The organic solvent is moved from the carrier gas introduced from the direct path to the hot carrier gas by alternately contacting the second adsorption / desorption element with the high temperature carrier gas introduced from the high temperature path through the means,
The first adsorption element desorption treatment period for desorbing the organic solvent from the first adsorption / desorption element is from the high-temperature path in the first stage, and the second adsorption stage from the direct path in the latter stage of the first adsorption / desorption element desorption process period. 2 carrier gas is introduced into the adsorption / desorption treatment device, and
In a predetermined period after the first adsorption / desorption element desorption process period ends, the carrier gas discharged from the second adsorption / desorption treatment apparatus is introduced into the condensation collection apparatus from the bypass, and from the condensation collection apparatus. The organic solvent recovery system, wherein the discharged carrier gas is introduced into the second adsorption / desorption treatment apparatus from the high temperature path. A third temperature adjusting means for adjusting the temperature of the carrier gas to a low temperature on the direct path;
In the latter stage of the first adsorption / desorption element desorption process period, the carrier gas discharged from the first adsorption / desorption process device is cooled to a low temperature by the second temperature adjusting means, and the second adsorption / desorption process is performed from the direct path. The organic solvent recovery system according to claim 2, wherein the organic solvent recovery system is introduced into the apparatus.   The carrier gas introduced from the direct path into the second adsorption / desorption device and the carrier gas introduced from the high-temperature path flow in a counterflow direction and contact the second adsorption / desorption element. The organic solvent collection | recovery system of any one of Claims 1-3.   The organic solvent recovery system according to any one of claims 1 to 4, wherein the first adsorption / desorption element and / or the second adsorption / desorption element includes activated carbon fibers.   The organic solvent recovery system according to claim 1, wherein the carrier gas is an inert gas.   The organic solvent recovery system according to any one of claims 1 to 6, wherein a boiling point of at least one of the organic solvents contained in the gas to be treated is 130 ° C or higher.   The organic solvent recovery system according to any one of claims 1 to 7, wherein at least one of the organic solvents contained in the gas to be treated has an unsaturated bond.