JP6458465B2 - Organic solvent recovery system - Google Patents

Description

  The present invention relates to an organic solvent recovery system, and more particularly to an organic solvent recovery system that condenses and recovers an organic solvent from exhaust gas with high efficiency.

As an organic solvent-containing gas treatment system that recovers organic solvent from exhaust gas, the organic solvent in the organic solvent-containing gas is adsorbed and removed by an adsorption element containing an adsorbent, and the adsorbed organic solvent is heated with air. There is known a system in which a gas containing a desorbed and desorbed organic solvent is condensed and recovered by a cooling means (for example, Patent Document 1).
In the above organic solvent-containing gas treatment, when the organic solvent in the exhaust gas is concentrated and recovered by cooling condensation, heating or high concentration exhaust gas when desorbing the organic solvent adsorbed from the adsorbing element containing the adsorbent. And energy is required for cooling to liquefy and condense desorption gas. In recent years, it has become an urgent task to efficiently recover the organic solvent in the organic solvent recovery system and to reduce the energy used in the organic solvent recovery system.

JP 2007-44595 A

  The present invention has been made against the background of the problems of the prior art, and further reduces the energy used in the organic solvent recovery system and has an arrangement capable of efficiently recovering the organic solvent. It is a problem to provide.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by the following means, and have reached the present invention.
That is, the present invention is as follows.
1. An organic solvent recovery system for recovering an organic solvent from an exhaust gas having an organic solvent discharged from a production facility having a temperature of 50 ° C to 200 ° C,
The exhaust gas is introduced into a cooler that condenses and recovers the organic solvent by a cooling operation, and is discharged as exhaust gas with a reduced concentration of the organic solvent.
A part of the exhaust gas in which the concentration of the organic solvent is reduced circulates by returning it to the production facility,
The remainder of the exhaust gas in which the concentration of the organic solvent is reduced is introduced into the adsorption part of the organic solvent concentrator having the adsorption element, and the organic solvent concentration is further reduced and discharged.
It is concentrated by the organic solvent concentrator and discharged as a concentrated gas from the desorption part, and the concentrated gas is introduced into the cooler.
Organic solvent recovery system.
2. An exhaust gas having an organic solvent discharged from the production facility at a temperature of 50 ° C. to 200 ° C .;
A part of the exhaust gas in which the concentration of the organic solvent to be circulated by returning to the production facility is reduced,
2. The organic solvent recovery system according to 1 above, wherein heat is exchanged by a heat exchanger.
3. 3. The organic solvent concentration of the exhaust gas in which the concentration of the organic solvent discharged from the cooler is reduced by introducing the exhaust gas into the cooler at a constant humidity by dehumidification or humidification means. Organic solvent recovery system.
4). The humidification means humidifies the exhaust gas and introduces it into the cooler, thereby increasing the amount of the organic solvent condensed and recovered by the cooling operation of the cooler, and the concentration of the organic solvent discharged from the cooler is increased. 3. The organic solvent recovery system according to 1 or 2 above, further reducing the organic solvent concentration in the reduced exhaust gas.
5. 5. The organic solvent recovery system according to any one of 1 to 4 above, wherein the organic solvent in the exhaust gas having a temperature of 50 ° C. to 200 ° C. containing the organic solvent discharged from the production facility is a water-soluble organic solvent.
6). The organic solvent in the exhaust gas containing the organic solvent discharged from the production facility is 50 ° C. to 200 ° C. is n-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, or n- 6. The organic solvent recovery system according to any one of 1 to 5 above, which is decane.

  According to the organic solvent recovery system according to the configuration of the present invention, it is possible to efficiently recover the organic solvent while reducing the energy used in the organic solvent recovery system.

It is a figure which shows the structure of the organic-solvent collection | recovery system which concerns on embodiment of this invention. It is a perspective view shown with the waste gas which flows the structure of the organic-solvent concentration apparatus which concerns on embodiment of this invention.

Hereinafter, an organic solvent recovery system according to an embodiment of the present invention will be described in detail with reference to the drawings.
In the following description of the embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

  FIG. 1 is a diagram showing a configuration of an organic solvent recovery system according to an embodiment of the present invention. As shown in FIG. 1, the organic solvent recovery system according to the embodiment of the present invention includes a production facility (1000) that is provided in various factories or research facilities and discharges exhaust gas containing an organic solvent. Yes.

  The organic solvent recovery system according to the present embodiment is an organic solvent recovery system that separates and recovers an organic solvent from exhaust gas while circulating the exhaust gas containing the organic solvent discharged from the production facility (1000).

  In the organic solvent recovery system shown in FIG. 1, a production facility (1000), a heat exchanger (100), an organic solvent concentrator (500), a cooler (200) and a recovery tank (300) having a recovery tank and drying A heater (400) and a regenerative heater (600) are connected. The function of each component will be described below.

(Heat exchanger 100)
The heat exchanger (100) is composed of a heat radiating side (100a) and a heat receiving side (100b). Exhaust gas from the production facility (1000) is passed through the heat radiating side (100a), and the heat receiving side (100b). The exhaust gas (G4) from the cooler is passed through. By exchanging different exhaust gases through different pipes, heat energy is exchanged between the exhaust gases.

(Cooler 200, recovery tank 300)
The cooler (200) uses cooling water or the like to condense the exhaust gas from the production facility (1000) and the desorption gas from the organic solvent concentrating device (500), and the recovered liquid containing a high concentration of organic solvent and the organic Separated into exhaust gas with reduced solvent concentration. The recovered liquid is recovered in the recovery tank (300), and the exhaust gas in which the concentration of the organic solvent is reduced is discharged toward the facility (1000) and toward the organic solvent concentrator (500).

(Organic solvent concentrator 500)
The organic solvent concentrator (500) has an adsorbing element capable of reversibly adsorbing and desorbing an organic solvent. The adsorbing element adsorbs the organic solvent in the exhaust gas when the exhaust gas having a temperature lower than the predetermined temperature is passed, and desorbs the adsorbed organic solvent when the exhaust gas having the predetermined temperature or higher is passed. The organic solvent concentrator (500) is composed of an adsorption part (51) and a desorption part (52).

  As the adsorbing element, an adsorbing element containing activated carbon or an adsorbing element containing hydrophobic zeolite can be used. When an adsorbing element containing activated carbon or hydrophobic zeolite is used, the adsorbed organic solvent is desorbed when exhaust gas of about 50 ° C. or higher is passed, and exhaust gas when exhaust gas lower than about 50 ° C. is passed. Adsorb organic solvent in it.

(Drying heater 400)
The drying heater (400) raises the temperature of the exhaust gas flowing through the adsorption section (51) to a predetermined temperature.

(Regenerative heater 600)
The regenerative heater (600) raises the temperature of the exhaust gas flowing through the desorption part (52) to a predetermined temperature.

Hereinafter, the connection relationship of each component will be described.
The heat release side (100a) of the production facility (1000) and the heat exchanger (100) is connected by a pipe (L1), and the heat receiving side (100b) is connected by a pipe (L6).

  The heat dissipation side (100a) of the heat exchanger (100) and the cooler (200) are connected by a pipe (L2) and a pipe (L3). The cooler (200) and the heat receiving side (100b) of the heat exchanger (100) are connected by a pipe (L5). The pipe (L5) is provided with a valve (V111). The cooler (200) and the recovery tank (300) are connected by a pipe (L4). The cooler (200) and the drying heater (400) are connected by a pipe (L7). The pipe (L7) is provided with a valve (V112).

  The drying heater (400) and the adsorption part (51) of the organic solvent concentrator (500) are connected by a pipe (L8).

  A pipe (L9) for discharging exhaust gas to the outside of the system is connected to the outlet of the adsorption section (51) of the organic solvent concentrator (500). The pipe (L9) is provided with a valve (V113). A pipe (L10) branches from between the adsorption part (51) and the valve (V113) and is connected to the regenerative heater (600). The pipe (L10) is provided with a valve (V114).

  The desorption part (52) of the regenerative heater (600) and the organic solvent concentrator (500) is connected by a pipe (L11).

  The desorption part (52) outlet and the pipe (L2) are connected by a pipe (L12).

(Organic solvent recovery system)
Hereinafter, a system for recovering n-methyl-2-pyrrolidone using the organic solvent recovery system configured as described above will be described.

  As shown in FIG. 1, the exhaust gas (G1) containing n-methyl-2-pyrrolidone discharged from the production facility (1000) is introduced into an organic solvent recovery system through a pipe (L1). For example, the exhaust gas (G1) has an air volume of 1400 NCMM, an n-methyl-2-pyrrolidone concentration of 1150 ppm, and a temperature of 100 ° C.

  The exhaust gas (G1) flows through the heat radiating side (100a) of the heat exchanger (100), thereby radiating heat to become exhaust gas (G2). For example, the exhaust gas (G2) has an air volume of 1400 NCMM, an n-methyl-2-pyrrolidone concentration of 1150 ppm, and a temperature of 55 ° C.

  The exhaust gas (G2) merges with the exhaust gas (G11) from the outlet of the desorption part (52) of the organic solvent concentrator (500) to become a mixed exhaust gas (G3). The mixed exhaust gas (G3) passes through the pipe (L3) and flows to the cooler (200). For example, the exhaust gas (G3) has an air volume of 1405 NCMM, an n-methyl-2-pyrrolidone concentration of 1152 ppm, and a temperature of 55 ° C.

  The exhaust gas (G3) is cooled by being passed through the cooler (200), whereby the exhaust gas (G4) containing n-methyl-2-pyrrolidone at a low concentration and the n-methyl-2-pyrrolidone at a high concentration Into the recovered liquid.

  The recovered liquid flows through the pipe (L4) and is recovered in the recovery tank (300). In this embodiment, the concentration of n-methyl-2-pyrrolidone that flows through the collection tank and is collected is 59 wt%. Further, the separated exhaust gas (G4) containing a low concentration of n-methyl-2-pyrrolidone is branched out to the pipes (L5, 7). The air volume to be branched is adjusted by valves (V111, 112).

  The exhaust gas (G4) that has passed through the pipe (L5) is introduced to the heat receiving side (100b) of the heat exchanger (100). For example, the exhaust gas (G4) has an air volume of 1260 NCMM, an n-methyl-2-pyrrolidone concentration of 70 ppm, and a temperature of 10 ° C. The exhaust gas (G4) flows through the heat radiation side (100b) of the heat exchanger (100), thereby receiving heat and becoming exhaust gas (G5). For example, the exhaust gas (G5) has an air volume of 1260 NCMM, an n-methyl-2-pyrrolidone concentration of 70 ppm, and a temperature of 55 ° C.

  The exhaust gas (G5) is mixed with the exhaust gas newly exhausted from the production facility (1000), and becomes exhaust gas (G1) and circulates in the system.

  The exhaust gas (G6) that has passed through the pipe (L7) flows through the drying heater (400), is heated to a certain temperature, and becomes exhaust gas (G7). For example, the exhaust gas (G6) has an air volume of 145 NCMM, an n-methyl-2-pyrrolidone concentration of 70 ppm, and a temperature of 10 ° C. The exhaust gas (G6) is heated by passing through the drying heater (400) and becomes exhaust gas (G7).

  The exhaust gas (G7) passes through the pipe (L8), flows into the adsorption part (51) of the organic solvent concentrator (500), adsorbs n-methyl-2-pyrrolidone, and becomes exhaust gas (G8). The exhaust gas (G8, G9) is branched out from the adsorption part (51) outlet through the pipes (L9, 10). The air volume is adjusted by a valve (V113, 114). A part of the branched exhaust gas passes through the pipe (L9) and is discharged out of the system as exhaust gas (G8). For example, the air volume is 140 NCMM, the concentration of n-methyl-2-pyrrolidone is 3 ppm, and the temperature is 18 ° C. The remaining exhaust gas (G9) passes through the pipe (L10) and flows into the regenerative heater (600). For example, the exhaust gas (G9) has an air volume of 5 NCMM, a concentration of n-methyl-2-pyrrolidone of 10 ppm, and a temperature of 50 ° C.

  The exhaust gas (G9) flowing through the regenerative heater (600) is heated to a certain temperature and becomes exhaust gas (G10). For example, the exhaust gas (G10) has an air volume of 5 NCMM, a concentration of n-methyl-2-pyrrolidone of 10 ppm, and a temperature of 130 ° C.

  The exhaust gas (G10) flows into the desorption part (52) of the organic solvent concentrator (500). Since the exhaust gas (G10) is 50 ° C. or higher, the n-methyl-2-pyrrolidone adsorbed by the adsorption element of the desorption part (52) is desorbed to become exhaust gas (G11). For example, the exhaust gas (G11) has an air volume of 5 NCMM, a concentration of n-methyl-2-pyrrolidone of 1680 ppm, and a temperature of 85 ° C. The exhaust gas (G11) passes through the pipe (L12) and joins the pipe (L2).

Hereinafter, the structure of the organic solvent concentrator according to the present embodiment will be described.
FIG. 2 is a perspective view showing together with the exhaust gas flowing through the structure of the organic solvent concentrator according to this embodiment.

  As shown in FIG. 2, the organic solvent concentrator of this embodiment is of a rotor type, and an adsorbing element is positioned around the rotation shaft (511) to allow exhaust gas to flow in the axial direction of the rotation shaft (511). The adsorbent (510) is included. The rotating shaft (511) is rotationally driven by a motor or the like (not shown).

  Specifically, in the tubular adsorbent (510), adsorbing elements having a honeycomb structure are stacked concentrically over a plurality of layers. In FIG. 2, the end of the cylindrical adsorbent (510) located on the front side of the paper surface is defined as one end (514) in the axial direction of the rotation axis (511) of the cylindrical adsorbent (510). On the other hand, the end of the cylindrical adsorbent (510) located on the far side of the paper surface is the other end (515) in the axial direction of the rotation axis (511) of the cylindrical adsorbent (510).

  Exhaust gas (G7) having a predetermined temperature of 50 ° C. or less passes from one end (514) side of the cylindrical adsorbent (510) to the desorption part (51) which is another part of the cylindrical adsorbent (510). Exhaust gas (G8) that is part of the exhaust gas that has flowed and the organic solvent has become a predetermined concentration or less is exhausted outside the system. The remaining exhaust gas (G9) circulates in the system without being exhausted. Although not shown, the temperature of the exhaust gas (G9) is increased by a heater or the like to become exhaust gas (G10).

  Exhaust gas (G10) having a predetermined temperature of 50 ° C. or higher is passed from the other end (515) side of the cylindrical adsorbent (510) to the desorption part (52) which is a part of the cylindrical adsorbent (510). It becomes exhaust gas (G11).

  When the cylindrical adsorber (510) rotates about the rotation axis (511), a part of the cylindrical adsorber (510) becomes the adsorbing portion (51) and the other of the cylindrical adsorbent (510). The part becomes a desorption part (52).

  The cylindrical adsorbent (510) rotates at a predetermined speed in the direction indicated by the arrow (501) in the figure, with the rotation axis (511) as the center of rotation. Thereby, the adsorption | suction element of a cylindrical adsorption body (510) moves to a desorption part (52) from an adsorption | suction part (51). Thus, the organic solvent can be continuously recovered by rotating the cylindrical adsorbent (510) and treating the exhaust gas.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It does not become a basis of limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the scope of claims. Moreover, all the changes within the meaning and range equivalent to a claim are included.

  According to the organic solvent recovery system according to the configuration of the present invention, it is possible to efficiently recover the organic solvent while reducing the energy used in the organic solvent recovery system, which greatly contributes to the industry.

1: Organic solvent recovery system 51: Adsorption part 52: Desorption part 100: Heat exchanger,
100a: Heat radiation side 100b: Heat reception side 200: Cooler 300: Recovery tank 400: Drying heater 500: Organic solvent concentrator 501: Rotation direction arrow 510: Cylindrical adsorbent 511: Rotating shaft 514: One end 515: The other end 600 : Regenerative heater 1000: Production equipment G1, G2, G3, G4, G5, G6, G7, G8, G9, G10, G11: Exhaust gas L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12: Piping V111, V112, V113, V114: Valve

Claims (6)

An organic solvent recovery system for recovering an organic solvent from an exhaust gas having an organic solvent discharged from a production facility having a temperature of 50 ° C to 200 ° C,
The exhaust gas is introduced into a cooler that condenses and recovers the organic solvent by a cooling operation, and is discharged as exhaust gas with a reduced concentration of the organic solvent.
A part of the exhaust gas in which the concentration of the organic solvent is reduced circulates by returning it to the production facility,
The remainder of the exhaust gas in which the concentration of the organic solvent is reduced is introduced into the adsorption part of the organic solvent concentrator having the adsorption element, and the organic solvent concentration is further reduced and discharged.
It is concentrated by the organic solvent concentrator and discharged as a concentrated gas from the desorption part, and the concentrated gas is introduced into the cooler.
Organic solvent recovery system. An exhaust gas having an organic solvent discharged from the production facility at a temperature of 50 ° C. to 200 ° C .;
A part of the exhaust gas in which the concentration of the organic solvent to be circulated by returning to the production facility is reduced,
The organic solvent recovery system according to claim 1, wherein heat exchange is performed by a heat exchanger.   The organic solvent concentration of the exhaust gas in which the concentration of the organic solvent discharged from the cooler is reduced is stabilized by introducing the exhaust gas into the cooler at a constant humidity by dehumidifying or humidifying means. The organic solvent recovery system described.   The humidification means humidifies the exhaust gas and introduces it into the cooler, thereby increasing the amount of the organic solvent condensed and recovered by the cooling operation of the cooler, and the concentration of the organic solvent discharged from the cooler is increased. The organic solvent collection | recovery system of Claim 1 or 2 which further reduces the organic solvent density | concentration of the reduced waste gas.   The organic solvent recovery system according to any one of claims 1 to 4, wherein the organic solvent in the exhaust gas at a temperature of 50 ° C to 200 ° C containing the organic solvent discharged from the production facility is a water-soluble organic solvent.   The organic solvent in the exhaust gas containing the organic solvent discharged from the production facility is 50 ° C. to 200 ° C. is n-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, or n- It is a decane, The organic-solvent collection | recovery system in any one of Claims 1-5.