Organic solvent recovery system

Abstract

This prevents the organic solvent that has evaporated again during the shutdown of the organic solvent recovery system from being adsorbed onto the adsorption / desorption elements. The first flow path (F1) is the path through which the gas to be treated is introduced into the condensation recovery unit (10). The second flow path (F2) is the path through which the cooled gas travels from the condensation recovery unit (10) to the adsorption / desorption treatment unit (50). A first on / off valve (101) is provided in the first flow path (F1) to open and close the first flow path (F1). A second on / off valve (102) is provided in the second flow path (F2) to open and close the second flow path (F2). A gas supply path (110) connects the first on / off valve (101) to the condensation recovery unit (10). The gas supply path (110) serves as the path for supplying inactive gas to the condensation recovery unit (10). A gas discharge path (120) serves as the path through which inactive gas is discharged from the condensation recovery unit (10).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an organic solvent recovery system. BACKGROUND

[0002] International Publication No. 2021 / 132071 (Patent Document 1) discloses an organic solvent recovery system that recovers an organic solvent from a treated gas by adsorbing, with an adsorption-desorption element, an uncondensed organic solvent after a portion of the organic solvent contained in the treated gas is condensed in a condensation recovery device.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: International Publication No. 2021 / 132071 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In some cases, the temperature of the condensation recovery device rises due to the outside air temperature in the stop of the organic solvent recovery system, and the liquid organic solvent remaining in the condensation recovery device volatilizes again. When the organic solvent that has volatilized again is adsorbed to the adsorption-desorption element, the performance of the adsorption-desorption treatment device decreases at the next start of the organic solvent recovery system.

[0008] In the present disclosure, an organic solvent recovery system capable of inhibiting the adsorption of an organic solvent to an adsorption-desorption element in the stop of the organic solvent recovery system is provided.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] In the present disclosure, the following organic solvent recovery system is provided.

[0011] (First item) An organic solvent recovery system that separates and recovers an organic solvent from a treated gas containing the organic solvent is provided with a condensation recovery device, an adsorption-desorption treatment device, a first flow path, a second flow path, a first on-off valve, a second on-off valve, a gas supply path, and a gas discharge path. The condensation recovery device cools the treated gas, thereby condensing the organic solvent contained in the treated gas, and discharges the cooled treated gas having a reduced concentration of the contained organic solvent. The adsorption-desorption treatment device has an adsorption-desorption element that adsorbs and desorbs the organic solvent contained in the cooled treated gas. The adsorption-desorption treatment device alternately performs adsorption of the organic solvent into the adsorption-desorption element by introducing the cooled treated gas and desorption of the organic solvent from the adsorption-desorption element by introducing a desorption gas. The first flow path is a path through which the treated gas is introduced to the condensation recovery device. The second flow path is a path through which the cooled treated gas goes from the condensation recovery device to the adsorption-desorption treatment device. The first on-off valve is provided in the first flow path. The first on-off valve opens and closes the first flow path. The second on-off valve is provided in the second flow path. The second on-off valve opens and closes the second flow path. The gas supply path becomes a path through which a non-active gas is supplied to the condensation recovery device. The gas supply path is connected between either one of the first on-off valve and the second on-off valve and the condensation recovery device. The gas discharge path becomes a path through which the non-active gas is discharged from the condensation recovery device.

[0012] (Second item) The organic solvent recovery system described in the first item can also be provided with a gas supply valve that opens and closes the gas supply path, and the non-active gas is supplied to the condensation recovery device via the gas supply path after the gas supply valve is set to an open state.

[0013] (Third item) The organic solvent recovery system described in the first item or the second item can also be provided with a gas discharge valve that opens and closes the gas discharge path, and the non-active gas discharged from the condensation recovery device passes through the gas discharge path after the gas discharge valve is set to an open state.

[0014] (Fourth item) In the organic solvent recovery system described in any one of the first to third items, the condensation recovery device can have a condensation section that condenses the organic solvent, and a recovery tank that recovers the condensed liquid organic solvent, and the organic solvent recovery system can further be provided with a return gas path that connects a gas layer portion on the organic solvent stored in the recovery tank and a path of the non-active gas discharged from the condensation recovery device.

[0015] (Fifth item) The organic solvent recovery system described in any one of the first to fourth items can further be provided with a temperature transmitter that detects and transmits the temperature of the cooled treated gas.

[0016] (6) In the organic solvent recovery system according to any one of the items 1 to 5, during a period in which the supply of the treated gas to the organic solvent recovery system is stopped, the first and second on-off valves can be closed, and a non-active gas can be supplied from the gas supply path to the condensation recovery device, whereby the treated gas in the condensation recovery device is replaced with the non-active gas.

[0017] Effects of Invention

[0018] According to the organic solvent recovery system of the present disclosure, the organic solvent that has been re-vaporized during the stop of the organic solvent recovery system can be inhibited from being adsorbed to the adsorption-desorption element. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a diagram that schematically shows the structure of the organic solvent recovery system of the first embodiment.

[0020] Figure 2 is a diagram that schematically shows the structure of the organic solvent recovery system of the second embodiment.

[0021] Figure 3 is a diagram that schematically shows the structure of the organic solvent recovery system of the third embodiment. DETAILED DESCRIPTION

[0022] Hereinafter, the embodiments will be described based on the drawings. In the following description, the same reference numerals are assigned to the same components and constituent elements. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated. The structures are extracted from the embodiments, and they are arbitrarily combined, which is predetermined from the beginning.

[0023] [First Embodiment]

[0024] Figure 1 is a diagram that schematically shows the structure of the organic solvent recovery system 1 of the first embodiment. A treated gas containing an organic solvent is discharged from a production device 90. The organic solvent recovery system 1 is a system that separates and recovers the organic solvent from the treated gas. The organic solvent contained in the treated gas can be, for example, a low-boiling-point solvent having a boiling point of 100°C or lower.

[0025] More specifically, the organic solvent can also be dichloromethane, chloroform, carbon tetrachloride, ethylene chloride, trichloroethane, trichloroethylene, dichloropropane, Freon-112, Freon-113, hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC), hydrofluoroolefin (HFO), iodomethane, and the like halogen-based organic solvents. The organic solvent can also be methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, vinyl acetate, methyl propionate, ethyl propionate, methyl acrylate, ethyl acrylate, methyl methacrylate, diethyl carbonate, and the like ester-based organic solvents. The organic solvent can also be acetone, methyl ethyl ketone (MEK), butanedione, and the like ketone-based organic solvents. The organic solvent can also be diethyl ether, dipropyl ether, tetrahydrofuran, ethylene glycol diethyl ether, dibutyl ether, epoxide, and the like ether-based organic solvents. The organic solvent can also be acrylonitrile and the like nitrile-based organic solvents. The organic solvent can also be methanol, ethanol, isopropyl alcohol, and the like alcohol-based organic solvents. The organic solvent can also be n-pentane, n-hexane, isohexane, cyclohexane, methylcyclohexane, n-heptane, and the like hydrocarbon-based organic solvents. The organic solvent can also be benzene and the like aromatic-based organic solvents.

[0026] As shown in FIG. 1, the organic solvent recovery system 1 mainly includes a condensation recovery device 10 and an adsorption and desorption treatment device 50. Figure 1

[0027] The treated gas discharged from the production apparatus 90 is introduced into the condensation recovery device 10 via a first flow path F1. The first flow path F1 is a path for introducing the treated gas into the condensation recovery device 10. The condensation recovery device 10 has a condensation section 20. The condensation section 20 has a cooling section 21, a separation section 22, and a chamber 23.

[0028] The cooling section 21 cools the treated gas passing through the cooling section 21. The cooling section 21 condenses a part of the organic solvent contained in the treated gas by cooling the treated gas. The separation section 22 separates the condensed organic solvent in a liquid form from the treated gas.

[0029] The manner in which the cooling section 21 cools the treated gas is not particularly limited. The cooling section 21 can be a heat exchanger that cools the treated gas by heat exchange between a coolant such as cooling water, cold water, brine, and the like and the treated gas. The flow rate and temperature of the coolant and the like cooling conditions can be appropriately determined depending on the organic solvent contained in the treated gas.

[0030] The manner in which the separation section 22 separates the organic solvent in a liquid form is not particularly limited. The separation section 22 can use, for example, a mesh-like structure that contacts and captures droplets such as a mist eliminator, a filter, a mesh, and the like.

[0031] ​Chamber 23 is a structure with a certain capacity. The gas to be processed after the organic solvent is separated in the separation section 22 passes through chamber 23, which is a hollow space. Cooled processing gas, containing a reduced concentration of organic solvent, is discharged from chamber 23. The cooled processing gas contains uncondensed organic solvent. The cooled processing gas discharged from the condensation recovery unit 10 flows through a second flow path F2. The second flow path F2 is the path taken by the cooled processing gas from the condensation recovery unit 10 to the adsorption-desorption processing unit 50.

[0032] The condensation recovery device 10 includes a recovery tank 30. The recovery tank 30 is positioned below the separation section 22. The separation section 22 and the recovery tank 30 are connected via a sixth flow path F6. The liquid organic solvent condensed by the cooling section 21 and captured by the separation section 22 is collected in the recovery tank 30 by gravity via the sixth flow path F6. Inside the recovery tank 30, a liquid storage section 32 for storing the liquid organic solvent and a gas layer section 31 above the liquid storage section 32 are formed. The diameter of the sixth flow path F6 may also be smaller than the diameter of the second flow path F2.

[0033] The liquid organic solvent stored in the liquid storage section 32 is recovered as recovery liquid L3. A pump (not shown) may also be installed in the flow path of the recovery liquid L3. A level gauge (not shown) may also be installed in the recovery tank 30. The pump may be started to begin recovering the recovery liquid L3 when the level gauge detects that the organic solvent level in the recovery tank 30 has reached its upper limit. As the liquid organic solvent flows out of the recovery tank 30, the organic solvent level in the recovery tank 30 decreases. Alternatively, the pump may be stopped to cease recovering the recovery liquid L3 when the level gauge detects that the organic solvent level has reached its lower limit.

[0034] A cooling gas blower 40 is installed in the second flow path F2. The cooling gas is sent out by the cooling gas blower 40 and into the adsorption-desorption treatment device 50. Alternatively, a gas heater can be installed in the second flow path F2 to heat the cooling gas. When the humidity of the cooling gas is too high, the adsorption-desorption treatment device 50 may not be able to perform at its full potential. By using a gas heater to increase the temperature of the cooling gas, thereby reducing the humidity of the cooling gas, the performance of the adsorption-desorption treatment device 50 can be improved.

[0035] Temperature transmitter 70 detects the temperature of the cooling gas flowing in the second flow path F2. When the second flow path F2 is equipped with the aforementioned gas heater, temperature transmitter 70 detects the temperature of the cooling gas upstream of the gas heater (closer to the condensation recovery unit 10). Temperature transmitter 70 transmits the detected temperature of the cooling gas to a control device (not shown). Based on the temperature of the cooling gas detected and transmitted by temperature transmitter 70, feedback control is performed to adjust the flow rate and temperature of the refrigerant supplied to the cooling unit 21.

[0036] The concentration of organic solvents in the cooling gas discharged from the condensation recovery unit 10 reaches a saturation concentration. The saturation concentration of organic solvents in the gas is determined by the temperature of the gas. The lower the temperature of the gas, the lower the concentration of organic solvents that can be contained in the gas. By monitoring the temperature of the cooling gas, it is possible to determine whether the concentration of organic solvents in the cooling gas is below the lower explosive limit. The cooling of the gas being processed in the cooling section 21 can be controlled based on the temperature of the cooling gas to ensure that the concentration of organic solvents in the cooling gas is below the lower explosive limit. As a result, the possibility of the cooling gas containing organic solvents exceeding the lower explosive limit being sent to the cooling gas blower 40 and igniting in an air atmosphere can be reduced.

[0037] The adsorption-desorption treatment device 50 has a first treatment tank 51. A hollow cylindrical adsorption-desorption element 52 is housed in the first treatment tank 51. A regulating damper 55 is provided at the lower part of the first treatment tank 51. A regulating damper 56 is provided in the first treatment tank 51 above the adsorption-desorption element 52. The adsorption-desorption treatment device 50 also has a second treatment tank 53. A hollow cylindrical adsorption-desorption element 54 is housed in the second treatment tank 53. A regulating damper 57 is provided at the lower part of the second treatment tank 53. A regulating damper 58 is provided in the second treatment tank 53 above the adsorption-desorption element 54.

[0038] The cooling gas passes radially from the outer side to the inner side relative to the adsorption / desorption elements 52 and 54, thereby contacting the cooling gas with the adsorption / desorption elements 52 and 54. At this time, the organic solvent contained in the cooling gas is adsorbed onto the adsorption / desorption elements 52 and 54. Thus, the cooling gas is purified. The purified clean gas G9 is discharged to the outside through the third flow path F3. The third flow path F3 is the path through which the clean gas G9, purified by the adsorption / desorption treatment device 50 for the adsorption of organic solvents, is discharged to the outside of the organic solvent recovery system 1.

[0039] A fourth flow path F4 branches off from the third flow path F3. A portion of the gas after adsorption treatment of the organic solvent by the adsorption-desorption treatment device 50 is used as desorption gas. The fourth flow path F4 is the path for supplying the desorption gas, which is used as heating gas, to the adsorption-desorption treatment device 50. A desorption gas blower 61, a desorption heater 62, and switching valves 63 and 64 are provided in the fourth flow path F4. The desorption gas is delivered by the desorption gas blower 61 and fed into the adsorption-desorption treatment device 50. The desorption heater 62 heats the desorption gas before it enters the adsorption-desorption treatment device 50.

[0040] Switching valves 63 and 64 switch the supply and stop of desorption gas to the first processing tank 51 and the supply and stop of desorption gas to the second processing tank 53. Switching valve 63 is located on the path of the desorption gas to the first processing tank 51. Switching valve 63 switches the opening and closing of the path of the desorption gas to the first processing tank 51. Switching valve 64 is located on the path of the desorption gas to the second processing tank 53. Switching valve 64 switches the opening and closing of the path of the desorption gas to the second processing tank 53. Switching valves 63 and 64 are on / off valves. Switching valves 63 and 64 can also be solenoid valves or electric valves.

[0041] The desorption gas passes from the radial inside to the outer side relative to the adsorption and desorption elements 52 and 54, thereby desorbing the organic solvent adsorbed on the adsorption and desorption elements 52 and 54.

[0042] Cooling gas is supplied to either the first processing tank 51 or the second processing tank 53 to adsorb organic solvents contained in the cooling gas. Meanwhile, desorption gas is supplied to the other of the first processing tank 51 and the second processing tank 53 to desorb the organic solvents adsorbed onto the adsorption / desorption elements 52 and 54. The adsorption of organic solvents onto the adsorption / desorption elements 52 and 54, and the desorption of organic solvents from the adsorption / desorption elements 52 and 54, are performed alternately.

[0043] Specifically, damper 55 switches the path of the cooling gas to the first treatment tank 51. Damper 56 switches the path of the clean gas discharged from the first treatment tank 51. Damper 57 switches the path of the cooling gas to the second treatment tank 53. Damper 58 switches the path of the clean gas discharged from the second treatment tank 53. The switching of the paths by dampers 55-58, and the opening and closing of switching valves 63 and 64, are interconnected.

[0044] The path of the cooling gas to the first treatment tank 51 is opened using the regulating damper 55, and the path of the clean gas from the first treatment tank 51 is opened using the regulating damper 56. At this time, the path of the cooling gas to the second treatment tank 53 is blocked using the regulating damper 57, and the path of the clean gas from the second treatment tank 53 is blocked using the regulating damper 58. The path of the desorption gas to the first treatment tank 51 is blocked by closing the switching valve 63, and the path of the desorption gas to the second treatment tank 53 is opened by opening the switching valve 64. Thus, the treatment of the cooling gas passing through the first treatment tank 51 to adsorb the organic solvent contained in the cooling gas using the adsorption-desorption element 52, and the treatment of the desorption gas passing through the second treatment tank 53 to desorb the organic solvent from the adsorption-desorption element 54 are performed simultaneously.

[0045] The path of the cooling gas to the second processing tank 53 is opened using the regulating damper 57, and the path of the clean gas from the second processing tank 53 is opened using the regulating damper 58. At this time, the path of the cooling gas to the first processing tank 51 is blocked using the regulating damper 55, and the path of the clean gas from the first processing tank 51 is blocked using the regulating damper 56. The path of the desorption gas to the second processing tank 53 is blocked by closing the switching valve 64, and the path of the desorption gas to the first processing tank 51 is opened by opening the switching valve 63. Thus, the treatment of the cooling gas passing through the second processing tank 53 to adsorb the organic solvent contained in the cooling gas using the adsorption-desorption element 54, and the treatment of the desorption gas passing through the first processing tank 51 to desorb the organic solvent from the adsorption-desorption element 52, are performed simultaneously.

[0046] As the adsorbent materials included in the adsorption / desorption elements 52 and 54, granular, powdered, fibrous, or honeycomb activated carbon, zeolite, silica gel, activated alumina, etc., can be used. Activated carbon fiber (ACF) is particularly preferred. For example, by fixing ACF to a support or by self-supporting it into a cylindrical shape and longitudinally arranging it within the core material, adsorption / desorption elements 52 and 54 can be formed.

[0047] A fifth flow path F5 is connected to the adsorption-desorption treatment device 50. The desorption gas, after the organic solvent has been desorbed from the adsorption-desorption elements 52 and 54, is discharged from the adsorption-desorption treatment device 50 as return gas. The fifth flow path F5 is connected to the first flow path F1. The return gas returns to the first flow path F1 via the fifth flow path F5 and mixes with the treated gas.

[0048] The organic solvent recovery system 1 also includes a gas purging device 100. The gas purging device 100 is used to supply an inert gas to the condensation recovery unit 10 during periods when the supply of the treated gas to the organic solvent recovery system 1 is interrupted. Specifically, the gas purging device 100 supplies an inert gas to the condenser section 20 and the gas layer section 31 of the recovery tank 30. The gas purging device 100 uses the inert gas as a pressurized gas to compress the organic solvent, which exists as a liquid within the condenser section 20. Furthermore, the gas purging device 100 uses the inert gas to replace the treated gas and air within the condenser section 20 and the gas layer section 31, thereby creating an inert gas atmosphere within the condenser section 20 and the gas layer section 31. An example of an inert gas is nitrogen.

[0049] The gas purging device 100 has a first on / off valve 101. The first on / off valve 101 is disposed in a first flow path F1. The first on / off valve 101 is a valve that opens and closes the first flow path F1. The gas purging device 100 also has a second on / off valve 102. The second on / off valve 102 is disposed in a second flow path F2. The second on / off valve 102 is a valve that opens and closes the second flow path F2.

[0050] In the flow direction of the gas being processed through the condensation recovery device 10, the first on / off valve 101 is located on the upstream side of the condensation recovery device 10, and the second on / off valve 102 is located on the downstream side of the condensation recovery device 10.

[0051] The gas purging device 100 has a gas supply path 110. The gas supply path 110 is connected to a first flow path F1 between the first on / off valve 101 and the condenser section 20. The gas supply path 110 is the path for supplying inactive gas G11 to the condensation recovery device 10. A gas supply valve 111 is provided in the gas supply path 110. The gas supply valve 111 is a valve that opens and closes the gas supply path 110. Inactive gas G11 is supplied to the condensation recovery device 10 via the gas supply path 110, which is in an open state via the gas supply valve 111.

[0052] A source for generating inert gas G11 is connected to gas supply path 110. The source is, for example, a nitrogen cylinder or a nitrogen generating device. Inert gas G11, with a pressure higher than atmospheric pressure, is supplied from the source to gas supply path 110.

[0053] The gas purging device 100 has a gas discharge path 120. The gas discharge path 120 connects to a second flow path F2 between the condenser section 20 and the second on / off valve 102. The gas discharge path 120 serves as the path for the inactive gas G12 to be discharged from the condensation recovery device 10. A gas discharge valve 121 is provided in the gas discharge path 120. The gas discharge valve 121 is a valve that opens and closes the gas discharge path 120. The inactive gas G12 discharged from the condensation recovery device 10 flows through the gas discharge path 120, where the gas discharge valve 121 is in the open state.

[0054] Inert gas G12 is discharged into the atmosphere through gas discharge path 120. A recovery device for recovering organic solvents contained in inert gas G12 can also be installed at the outlet of inert gas G12 discharged through gas discharge path 120. Alternatively, a replaceable adsorption element for adsorbing organic solvents contained in inert gas G12 can be installed at the outlet of inert gas G12 discharged through gas discharge path 120. This reduces the concentration of organic solvents in the inert gas G12 released into the atmosphere.

[0055] The first on / off valve 101, the second on / off valve 102, the gas supply valve 111, and the gas discharge valve 121 can also be electrically operated valves, such as solenoid valves whose valve cores are opened and closed by the electromagnetic force of an electromagnet, or electric valves operated by an electric motor. Alternatively, the first on / off valve 101, the second on / off valve 102, the gas supply valve 111, and the gas discharge valve 121 can also be valves whose opening degree is manually adjusted. The first on / off valve 101, the second on / off valve 102, the gas supply valve 111, and the gas discharge valve 121 are not limited to on / off valves. For example, the gas supply valve 111 can also be a check valve that allows inactive gas to flow from the generation source to the first flow path F1 and closes the reverse flow.

[0056] The gas purging device 100 also has a return gas path 130. The return gas path 130 connects the gas layer 31 on the organic solvent stored in the recovery tank 30 and the path through which the inactive gas G12 is discharged from the condensation recovery device 10, i.e., the second flow path F2. The return gas path 130 is connected to the second flow path F2 upstream of the gas discharge path 120 in the flow direction of the gas being processed. A portion of the inactive gas is introduced from the condensation section 20 into the gas layer 31 of the recovery tank 30 via the sixth flow path F6. The inactive gas returns from the gas layer 31 to the second flow path F2 via the return gas path 130.

[0057] The destination of the return gas path 130 is not limited to the second flow path F2. The return gas path 130 can also be connected to the gas discharge path 120, which is the path for the inactive gas G12. When the return gas path 130 is connected to the gas discharge path 120, it is connected to the gas discharge path 120 upstream of the gas discharge valve 121 (closer to the condensation recovery device 10).

[0058] During the supply of the gas to be treated to the organic solvent recovery system 1, the first on / off valve 101 and the second on / off valve 102 remain open. The condensation recovery device 10 is maintained in communication with both the production equipment 90 and the adsorption / desorption treatment device 50. The gas being treated discharged from the production equipment 90 is introduced into the condensation recovery device 10 via the first flow path F1. The cooled gas, after a portion of the organic solvent has been condensed and recovered by the condensation recovery device 10, is introduced into the adsorption / desorption treatment device 50 via the second flow path F2. At this time, the gas supply valve 111 and the gas discharge valve 121 remain closed.

[0059] During the period when the supply of the treated gas to the organic solvent recovery system 1 is stopped, the first on / off valve 101 is closed, and the production equipment 90 and the condensation recovery device 10 are disconnected. The second on / off valve 102 is closed, and the condensation recovery device 10 and the adsorption / desorption treatment device 50 are disconnected. In this state, the gas supply valve 111 is open. Inactive gas G11 is supplied to the condensation recovery device 10 from the gas supply path 110. The inactive gas G11 is sequentially introduced into the condensation section 20 via the gas supply path 110 and the first flow path F1.

[0060] A portion of the inactive gas flows sequentially through the cooling section 21, separation section 22, and chamber 23 within the condenser section 20, and is discharged from the condenser section 20 into the second flow path F2. A portion of the inactive gas is introduced from the separation section 22 of the condenser section 20 into the gas layer section 31 of the recovery tank 30 via the sixth flow path F6. The inactive gas returns from the gas layer section 31 of the recovery tank 30 to the second flow path F2 via the return gas path 130.

[0061] With the condenser section 20 and the gas layer section 31 filled with inactive gas, the gas discharge valve 121 is opened. The inactive gas G12 is discharged out of the system through the gas discharge path 120. Thus, both the condenser section 20 (where the organic solvent exists as a liquid, specifically the condenser tank 30 where the gaseous organic solvent is condensed into a liquid state) and the recovery tank 30 (where the liquid organic solvent is stored) of the condenser recovery device 10 are purged by the inactive gas. The treated gas and air within the condenser section 20 and the gas layer section 31 are replaced by the inactive gas.

[0062] If the condensation recovery device 10 can be sufficiently purged, the flow of inactive gas G11 is stopped, thus stopping the organic solvent recovery system 1. Alternatively, a timer can be used to measure the elapsed time from the start of supplying inactive gas G11, and the gas supply valve 111 and gas discharge valve 121 can be closed at the point when the predetermined time has elapsed to stop the supply of inactive gas G11. Alternatively, the concentration of organic solvent contained in the inactive gas G12 flowing in or exiting the gas discharge path 120 can be measured, and the gas supply valve 111 and gas discharge valve 121 can be closed at the point when the concentration of organic solvent has sufficiently decreased to stop the supply of inactive gas G11.

[0063] In the organic solvent recovery system 1, an adsorption-desorption treatment device 50 is arranged downstream of the condensation recovery device 10. Therefore, by using an inactive gas to purge the condensation recovery device 10, the performance degradation of the adsorption-desorption treatment device 50 can be suppressed.

[0064] exist Figure 1 In the example shown, the first on / off valve 101 is disposed in the first flow path F1, and the gas supply valve 111 is disposed in the gas supply path 110. The first on / off valve 101 and the gas supply valve 111 are configured as different valves. Not limited to this example, it is also possible to configure a three-way valve at the connection between the first flow path F1 and the gas supply path 110, which simultaneously performs the functions of both the first on / off valve 101 for opening and closing the first flow path F1 and the gas supply valve 111 for opening and closing the gas supply path 110. By using a three-way valve, compared to using different on / off valves to implement the first on / off valve 101 and the gas supply valve 111, the space required for valve configuration can be reduced.

[0065] Similarly, a three-way valve can be provided at the connection between the second flow path F2 and the gas discharge path 120. This three-way valve has the functions of both opening and closing the second on / off valve 102 of the second flow path F2 and opening and closing the gas discharge valve 121 of the gas discharge path 120.

[0066] exist Figure 1In the example shown, the gas supply path 110, which serves as the path for supplying inactive gas to the condensation recovery unit 10, is connected to the first flow path F1, and the gas discharge path 120, which serves as the path for the inactive gas to exit from the condensation recovery unit 10, is connected to the second flow path F2. Not limited to this example, it is also possible that the gas supply path 110, which serves as the path for supplying inactive gas to the condensation recovery unit 10, is connected to the second flow path F2, and the gas discharge path 120, which serves as the path for the inactive gas to exit from the condensation recovery unit 10, is connected to the first flow path F1. In this case, the return gas path 130 can be connected either to the first flow path F1 between the connection point of the gas discharge path 120 and the first flow path F1 and the condensation section 20, or it can be connected to the gas discharge path 120.

[0067] exist Figure 1 In the example shown, a gas discharge path 120 is connected to the second flow path F2, and a return gas path 130 is also connected to the second flow path F2. The inert gas flowing out of the gas layer section 31 is discharged into the atmosphere sequentially via the return gas path 130, the second flow path F2, and the gas discharge path 120. Not limited to this example, the gas discharge path 120, which becomes the path for the inert gas G12 to be discharged from the condensation recovery device 10, may also be connected to the gas layer section 31 of the recovery tank 30. In this case, the inert gas flowing out of the gas layer section 31 flows directly into the gas discharge path 120, thus the return gas path 130 can be omitted.

[0068] The condensation recovery device 10 may also have an L-shaped structure in which the direction of flow of the treated gas (or inactive gas) from the cooling section 21 to the separation section 22 intersects with the direction of flow of the treated gas (or inactive gas) from the separation section 22 to the chamber 23. In this case, a funnel-shaped receiving section for receiving the condensed organic solvent may also be provided below the separation section 22. This prevents the droplets of the condensed organic solvent from flowing out of the condensation section 20 into the second flow path F2 and reaching the adsorption-desorption treatment device 50.

[0069] [Second Implementation]

[0070] Figure 2 This is a diagram that schematically illustrates the structure of the organic solvent recovery system 1 according to the second embodiment. In the first embodiment, an example was described in which a portion of the gas after adsorption treatment of the organic solvent by the adsorption-desorption treatment device 50 was used as a desorption gas. Alternatively, it could be configured as follows: Figure 2 The structure shown introduces the desorption gas G8 from outside the system into the adsorption-desorption treatment apparatus 50. In this case, the desorption gas G8 can also be water vapor. Alternatively, the desorption gas G8 can be an inactive gas or heated air.

[0071] In addition to the first embodiment where the fifth flow path F5 is connected to the first flow path F1, in the second embodiment, a second condensation recovery device 80 is provided in the fifth flow path F5. The second condensation recovery device 80 condenses and recovers a portion of the organic solvent contained in the desorption gas. The second condensation recovery device 80 has a second condensation section 81 and a second recovery tank 82.

[0072] The desorption gas introduced into the second condensation and recovery unit 80 contains organic solvents desorbed from the adsorption-desorption elements 52 and 54. The second condensation unit 81 cools the desorption gas discharged from the adsorption-desorption treatment unit 50, causing a portion of the organic solvent contained in the desorption gas to condense. The condensed liquid organic solvent is collected in the second recovery tank 82. The liquid organic solvent stored in the second recovery tank 82 is recovered as recovery liquid L4.

[0073] The return gas, containing a reduced concentration of organic solvent, is discharged from the second condensation and recovery unit 80. The fifth flow path F5 is connected to the second flow path F2. The return gas returns to the second flow path F2 via the fifth flow path F5 and mixes with the cooling process gas.

[0074] [Third Implementation Method]

[0075] Figure 3 This is a diagram that schematically illustrates the structure of the organic solvent recovery system 1 according to the third embodiment. Unlike the first and second embodiments, the organic solvent recovery system 1 of the third embodiment includes a disc-shaped adsorption-desorption treatment device 50. The adsorption-desorption treatment device 50 has a first treatment tank 51 and a second treatment tank 53.

[0076] The adsorption-desorption treatment apparatus 50 has a rotating shaft and an adsorption-desorption element (not shown) disposed around the rotating shaft. By rotating the adsorption-desorption element around the rotating shaft, the adsorption-desorption element moves alternately towards the first treatment tank 51 and the second treatment tank 53.

[0077] A second flow path F2 and a third flow path F3 are connected to the first processing tank 51. Cooling gas is introduced into the first processing tank 51 through the second flow path F2, and the cooling gas comes into contact with the adsorption / desorption elements. At this time, the organic solvent contained in the cooling gas is adsorbed by the adsorption / desorption elements. Thus, the cooling gas is purified. The purified clean gas G9 is discharged to the outside through the third flow path F3.

[0078] A portion of the gas after adsorption treatment of organic solvent by the adsorption-desorption treatment device 50 is used as desorption gas. The adsorption-desorption element, which has adsorbed organic solvent in the first treatment tank 51, continuously moves to the second treatment tank 53. A fourth flow path F4 and a fifth flow path F5 are connected to the second treatment tank 53. The desorption gas is introduced into the second treatment tank 53 from the fourth flow path F4, and the desorption gas contacts the adsorption-desorption element, thus desorbing the organic solvent adsorbed on the element. The returned gas, after desorbing the organic solvent from the adsorption-desorption element, returns to the first flow path F1 via the fifth flow path F5 and mixes with the treated gas.

[0079] It can also replace the disc-shaped adsorption-desorption treatment device 50 described above, and the known cylindrical adsorption-desorption treatment device can be applied to the organic solvent recovery system 1.

[0080] [Functions and Effects]

[0081] There are also some descriptions that overlap with the above description, but when summarizing the characteristic structure and effects of this embodiment, it is as follows.

[0082] like Figures 1-3 As shown, the first flow path F1 is the path through which the gas to be treated is introduced into the condensation recovery unit 10. The second flow path F2 is the path through which the cooled gas travels from the condensation recovery unit 10 to the adsorption-desorption treatment unit 50. A first on / off valve 101 is provided in the first flow path F1 to open and close the first flow path F1. A second on / off valve 102 is provided in the second flow path F2 to open and close the second flow path F2. A gas supply path 110 connects the first on / off valve 101 and the condensation recovery unit 10. The gas supply path 110 serves as the path for supplying inactive gas to the condensation recovery unit 10. The gas discharge path 120 serves as the path through which inactive gas is discharged from the condensation recovery unit 10.

[0083] A first on / off valve 101 is provided upstream of the condensation recovery device 10, and a second on / off valve 102 is provided downstream of the condensation recovery device 10. When the organic solvent recovery system 1 is stopped, both the first on / off valve 101 and the second on / off valve 102 are closed. By stopping the organic solvent recovery system 1 with the second on / off valve 102 closed downstream, even if the liquid organic solvent remaining in the condensation recovery device 10 evaporates again, the evaporated organic solvent will not be introduced into the adsorption-desorption treatment device 50. This can suppress the situation where the organic solvent that evaporates again during the shutdown of the organic solvent recovery system is adsorbed onto the adsorption-desorption elements 52 and 54. Therefore, it is possible to prevent the adsorption-desorption elements 52 and 54 from heating up due to adsorption heat during the shutdown of the organic solvent recovery system. In addition, the performance of the adsorption-desorption treatment device 50 can be ensured when the organic solvent recovery system 1 is restarted next time.

[0084] An inert gas is supplied to the condensation and recovery device 10, where organic solvents may re-evaporate, thus filling the condensation section 20 and recovery tank 30 with an inert gas atmosphere. This atmosphere, rather than air, ensures that even if the temperature of residual organic solvents in the condensation section 20 or recovery tank 30 rises and they re-evaporate, the surrounding environment will only contain inert gas, preventing ignition even if the concentration of the organic solvent exceeds the lower explosive limit. Therefore, the safety of the organic solvent recovery system 1 during shutdown is improved.

[0085] like Figures 1-3 As shown, the inert gas can also be supplied to the condensation recovery unit 10 via the gas supply path 110 after the gas supply valve 111 is set to the open state. During the supply of the gas to be processed to the condensation recovery unit 10, the gas supply valve 111 is closed, thereby reliably stopping the supply of inert gas to the condensation recovery unit 10. When the supply of the gas to be processed to the condensation recovery unit 10 stops, the first on / off valve 101 is closed and the gas supply valve 111 is opened, thereby allowing the inert gas to be easily supplied to the condensation recovery unit 10 from the inert gas generation source connected to the gas supply path 110.

[0086] like Figures 1-3 As shown, the inactive gas discharged from the condensation recovery unit 10 can also be discharged through the gas discharge path 120 after the gas discharge valve 121 is set to an open state. By opening the gas discharge valve 121, the inactive gas can be easily discharged from the condensation recovery unit 10 to the outside of the system via the gas discharge path 120.

[0087] like Figures 1-3 As shown, alternatively, the return gas path 130 can connect the gas layer 31 of the organic solvent stored in the recovery tank 30 to the second flow path F2, which is the path for the inactive gas to be discharged from the condensation recovery device 10. A portion of the inactive gas introduced into the condensation section 20 flows sequentially through the cooling section 21, the separation section 22, and the chamber 23 from the second flow path F2 to the gas discharge path 120. A portion of the inactive gas introduced into the condensation section 20 is introduced from the separation section 22 through the sixth flow path F6 into the gas layer 31 of the recovery tank 30, and flows out of the recovery tank 30 sequentially through the return gas path 130 and the second flow path F2 to the gas discharge path 120.

[0088] By setting the return gas path 130, inert gas can reliably flow throughout the condenser section 20 and the gas layer section 31 of the recovery tank 30. This avoids the formation of dead spaces inside the condenser section 20 where inert gas is not adequately supplied, and allows for efficient and effective replacement of the condenser section 20 and the recovery tank 30 with inert gas.

[0089] like Figures 1-3 As shown, the temperature transmitter 70 can also detect and transmit the temperature of the cooling gas. By setting a feedback control that adjusts the flow rate and temperature of the refrigerant supplied to the cooling unit 21 based on the temperature of the cooling gas, the concentration of organic solvents contained in the cooling gas can be reliably maintained below the lower explosive limit.

[0090] Alternatively, the gas supply path 110, which becomes the path for supplying inactive gas to the condensation recovery device 10, can be connected to the second flow path F2, and the gas discharge path 120, which becomes the path for discharging inactive gas from the condensation recovery device 10, can be connected to the first flow path F1. For example... Figures 1-3 As shown, if the gas supply path 110 is connected to the first flow path F1 and the gas discharge path 120 is connected to the second flow path F2, the inactive gas flows from the first flow path F1 into the condenser 20 and then flows out of the condenser 20 into the second flow path F2. The flow direction of the inactive gas can be aligned with the flow direction of the gas being processed when it is supplied to the condensation recovery device 10. If liquid organic solvent remains in the cooling section 21, the liquid organic solvent can be carried by the flow of the inactive gas from the cooling section 21 to the separation section 22 and captured by the separation section 22 for recovery into the recovery tank 30. This reduces the concentration of organic solvent in the discharged inactive gas.

[0091] like Figures 1-3 As shown, during the period when the supply of the treated gas to the organic solvent recovery system 1 is stopped, the first on / off valve 101 and the second on / off valve 102 are closed, and an inactive gas is supplied to the condensation recovery device 10 from the gas supply path 110. This allows the treated gas within the condensation recovery device 10 to be replaced by the inactive gas. Therefore, the supply of re-evaporated organic solvent to the adsorption-desorption treatment device 50 can be reliably prevented, and the ignition of re-evaporated organic solvent can be reliably prevented.

[0092] All points of the embodiments disclosed herein are illustrative and should be considered as not limiting. The scope of the invention is shown not by the foregoing description but by the technical solutions, and is intended to include all modifications of the same meaning and scope.

[0093] Explanation of reference numerals in the attached figures

[0094] 1 Organic solvent recovery system, 10 Condensation recovery device, 20 Condensation section, 21 Cooling section, 22 Separation section, 23 Chamber, 30 Recovery tank, 31 Gas layer section, 32 Liquid storage section, 40 Cooling treatment gas blower, 50 Adsorption-desorption treatment device, 51 First treatment tank, 52, 54 Adsorption-desorption elements, 53 Second treatment tank, 55-58 Regulating dampers, 61 Desorption gas blower, 62 Desorption heater, 63, 64 Switching valve, 70 Temperature transmitter, 80 Second condensation recovery device, 81 Second condensation section, 82 Second recovery tank, 90 Production equipment, 100 Gas purging device, 101 First on / off valve, 102 Second on / off valve, 110 Gas supply path, 111 Gas supply valve, 120 Gas discharge path, 121 Gas discharge valve, 130 Return gas path, F1 First flow path, F2 Second flow path, F6 Sixth flow path, G11, G12 Inactive gas.

Claims

1. An organic solvent recovery system that separates and recovers an organic solvent from a treated gas containing the organic solvent, wherein the organic solvent recovery system comprises: a condensation recovery device that condenses the organic solvent contained in the treated gas by cooling the treated gas, and discharges the treated gas having a reduced concentration of the organic solvent contained therein as a cooled treated gas; an adsorption and desorption treatment device that has an adsorption and desorption element that adsorbs and desorbs the organic solvent contained in the cooled treated gas, and alternately performs adsorption of the organic solvent to the adsorption and desorption element by introducing the cooled treated gas, and desorption of the organic solvent from the adsorption and desorption element by introducing a desorption gas; a first flow path that is a path for introducing the treated gas to the condensation recovery device; a second flow path that is a path for the cooled treated gas from the condensation recovery device to the adsorption and desorption treatment device; a first on-off valve that is provided in the first flow path, and opens and closes the first flow path; a second on-off valve that is provided in the second flow path, and opens and closes the second flow path; a gas supply path that is connected between either one of the first on-off valve and the second on-off valve and the condensation recovery device, and becomes a path for supplying a non-active gas to the condensation recovery device; and a gas discharge path that becomes a path for discharging the non-active gas from the condensation recovery device.

2. The organic solvent recovery system according to claim 1, wherein the organic solvent recovery system comprises a gas supply valve that opens and closes the gas supply path, and the non-active gas is supplied to the condensation recovery device via the gas supply path in an open state after the gas supply valve.

3. The organic solvent recovery system according to claim 1, wherein the organic solvent recovery system comprises a gas discharge valve that opens and closes the gas discharge path, and the non-active gas discharged from the condensation recovery device passes through the gas discharge path in an open state after the gas discharge valve.

4. The organic solvent recovery system according to any one of claims 1 to 3, wherein the condensation recovery device has a condensation section that condenses the organic solvent, and a recovery tank that recovers the condensed liquid organic solvent, and the organic solvent recovery system further comprises a return gas path that connects a gas layer portion on the organic solvent stored in the recovery tank and a path for the non-active gas discharged from the condensation recovery device.

5. The organic solvent recovery system according to any one of claims 1 to 3, wherein the organic solvent recovery system further comprises a temperature transmitter that detects and transmits a temperature of the cooled treated gas.

6. The organic solvent recovery system according to any one of claims 1 to 3, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ During the period when the supply of the treated gas to the organic solvent recovery system is stopped, the first and second on-off valves are closed, and the non-active gas is supplied from the gas supply path to the condensation recovery device, whereby the treated gas in the condensation recovery device is replaced with the non-active gas.

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