JP2009101334A - Distilling apparatus of waste solvent containing solid component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distilling apparatus capable of recovering solvent from waste solvent containing solid components with a high recovery rate, and removing the solid components remaining in the apparatus without stopping heating operation in an evaporator. <P>SOLUTION: The distilling apparatus is provided with the evaporator 10 heating and evaporating waste solvent containing solid components, a waste solvent drawing out line 14 discharging the waste solvent from the evaporator 10, a separation tank 20 receiving the waste solvent from the waste solvent drawing out line 14 for sedimentation of the waste solvent, and a supernatant line returning supernatant of the waste solvent subjected to the sedimentation in the separation tank 20 to the evaporator 10. Thus, the amount of the solvent discarded together with the solid components is reduced to recover the solvent with high recovery rate, without stopping the heating operation in the evaporator 10 when discharging the solid components. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a distillation apparatus for purifying a waste solvent containing a solid component and recovering an organic solvent.

  An organic solvent is widely used as a cleaning liquid in a cleaning process for electronic parts and the like. The used organic solvent (waste solvent) has been conventionally recovered and reused, and the recovery method is to heat and vaporize the waste solvent and condense the vaporized vapor. The distillation purification method to collect is common.

For example, Patent Document 1 describes a distillation apparatus that vaporizes a solvent containing impurities with a falling film type reboiler (evaporator), sends the vaporized vapor to a rectifying unit, and condenses and recovers it.
Japanese Patent Laid-Open No. 2001-9201 ([0008], FIG. 1)

  In the conventional distillation apparatus, when the waste solvent containing solid components is intermittently or continuously supplied to the evaporator and heated, the volatile components in the waste solvent are vaporized and sent to the distillation section. Remains in the evaporator. For this reason, when the heating operation of the evaporator is continued, the concentration of the solid component in the waste solvent increases, and depending on the type of the solid component, the viscosity of the waste solvent increases and the evaporation rate of the volatile component may decrease. Further, if the waste solvent is continuously heated while the concentration of the solid component is high, the solid component may adhere to the wall surface of the heating unit and may be burnt.

  In order to prevent this, it is necessary to remove the solid component from the evaporator before the concentration of the solid component in the waste solvent becomes too high in the evaporator. At that time, in the conventional distillation apparatus, the solvent remaining in the evaporator is removed together with the solid components, so that a large amount of the solvent is discarded without being reused. Further, if the heating operation of the evaporator is stopped when removing the solid components, heat energy and time are lost, which is inefficient.

  The problem to be solved by the present invention is a distillation capable of recovering a solvent from a waste solvent containing a solid component at a high recovery rate and removing the solid component remaining in the apparatus without stopping the heating operation of the evaporator. Is to provide a device.

The distillation apparatus according to the present invention, which has been made to solve the above problems,
In a distillation apparatus that recovers a solvent component from a waste solvent containing a solid component,
An evaporator for heating the waste solvent to vaporize a solvent component;
A waste solvent line for draining the waste solvent from the evaporator;
A separation tank for receiving the waste solvent from the waste solvent line and settling and separating the waste solvent;
A supernatant line for returning the supernatant of the waste solvent settled and separated in the separation tank to the evaporator;
It is characterized by providing.

  The waste solvent is a solvent in which a solid component is mixed. In the distillation apparatus according to the present invention, the solvent component of the waste solvent becomes vapor in the evaporator and is separated from the waste solvent. The solid component of the waste solvent is sent from the evaporator to the separation tank together with the solvent component that has not been vaporized. The waste solvent (solid component and solvent component) sent to the separation tank is settled and separated in the separation tank, the solid component is precipitated, and the solvent component becomes a supernatant. The precipitated solid component is discharged from the separation tank, and the supernatant is returned to the evaporator by the supernatant line.

  In the distillation apparatus according to the present invention, the supernatant (solvent component) separated in the separation tank is returned from the separation tank to the evaporator, and the solid component is discharged from the separation tank. As a result, the solvent component is not wasted together with the solid component, and the solvent can be recovered from the waste solvent at a high recovery rate.

  Moreover, since the distillation apparatus according to the present invention precipitates and discharges solid components in a separation tank provided separately from the evaporator, the solid components remaining in the apparatus are removed without stopping the heating operation of the evaporator. Can do. Accordingly, heat energy and time are not lost, and distillation can be performed efficiently.

  Hereinafter, a distillation apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram of a distillation apparatus according to the present embodiment. This distillation apparatus includes an evaporator 10 that heats and vaporizes a waste solvent containing a solid component, a separation tank 20 that is provided below the evaporator 10 and settles and separates the waste solvent concentrated by the evaporator 10, and evaporation A distillation column 40 that separates waste solvent vapor flowing in from the can 10 using a difference in boiling point is a main component.

  A waste solvent supply line 11 that supplies waste solvent to the evaporator 10 is connected to the upper part of the evaporator 10. Inside the evaporator 10, a heating unit 12 that indirectly heats the waste solvent in the evaporator 10 with the heat of water vapor is provided. The heating unit 12 is desirably removable from the evaporator 10 in order to facilitate cleaning during maintenance or the like. The first water vapor supply line 13 for sending water vapor to the heating unit 12 is connected not only to the heating unit 12 but also to the evaporator 10, and can supply water vapor into the can of the evaporator 10. The waste solvent supply line 11, the first water vapor supply line 13, and each line described below appropriately include a valve for adjusting the flow rate of the fluid flowing through the waste solvent supply line 11, a flow meter for measuring flow rate, and the like.

  The bottom of the evaporator 10 and the top of the separation tank 20 are connected by a waste solvent extraction line 14 so that the waste solvent in the evaporator 10 flows down naturally and is extracted into the separation tank 20. A waste solvent extraction valve 15 for adjusting the flow rate of the waste solvent is provided in the vicinity of the evaporator 10 in the waste solvent extraction line 14. A compressed air supply line 16 for sending compressed air into the pipe is connected to the downstream side of the waste solvent extraction valve 15 in the waste solvent extraction line 14 (on the separation tank 20 side). Note that the waste solvent extraction valve 15 and other valves in this embodiment are automatic valves that open and close by electromagnetic or pneumatic pressure.

  The separation tank 20 is connected to the lower end of the cylindrical wall surface with a conical bottom that is convex downward, and the upper end of the wall surface is closed with a top plate. Below the separation tank 20, a drum can 21 is disposed for storing slurry generated by sedimentation and separation of the waste solvent. The slurry extraction line 24 that connects the bottom end of the separation tank 20 and the upper surface of the drum can 21 is provided with a slurry extraction valve 35 that controls the discharge timing of the slurry. It is desirable that the slurry extraction line 24 and the slurry extraction valve 35 have a large diameter of 150 A or more in order to prevent clogging by solid components. Above the separation tank 20 is disposed a waste solution capacitor 22 for condensing vapor generated from the waste solvent in the separation tank 20, and the inlet and outlet of the waste solution capacitor 22 are connected to the upper part of the separation tank 20 by a condensation line 23. .

  On the wall surface of the separation tank 20, there are three supernatant outlets (first supernatant outlet 25, second supernatant outlet 26, and third supernatant, which are outlets for the supernatant of the waste solvent. The liquid outlets 27) are installed at different heights. Each supernatant outlet is connected to a temporary storage tank 29 disposed at a position lower than each supernatant outlet by a supernatant outlet line 28. The temporary storage tank 29 is connected to the upper part of the evaporator 10 by a supernatant circulation line 30 equipped with a pump 31. A waste liquid line 34 connected to a waste liquid tank is connected to a downstream side (evaporator 10 side) of the supernatant liquid circulation line 30 from the pump 31.

  At the outlet of the waste solvent vapor in the evaporator 10, a wire mesh demister 33 that collects mist accompanying the vapor is installed. In place of the wire mesh demister 33, an interference plate, regular packing, or the like may be used. As the interference plate, a so-called collector using bent plates, an inverted cone, a radiator, or the like can be used. The outlet of the waste solvent vapor in the evaporator 10 is connected to the side surface of the distillation column 40 by the vapor line 32.

  The distillation tower 40 is configured to separate and condense components having different boiling points contained in the waste solution by passing the waste solution vapor therethrough. Therefore, in the distillation column 40, there are four packings (first packing 41, second packing 42, third packing 43, and fourth packing 44 in order from the bottom) for contacting with the passing steam. Is installed. For each packing, vapor condensation is facilitated by contact of the vapor with the liquid already condensed in the packing, as well as the packing itself. For each packing, it is desirable to use a regular packing having a regular structure that can cope with liquid load fluctuations and precision distillation. Note that the outlet of the waste solvent vapor of the evaporator 10 is connected to the side surface of the distillation tower 40 between the first packing 41 and the second packing 42 by the steam line 32.

  Immediately above each packing, there are four liquid dispersing devices (the first liquid dispersing device 45, the second liquid dispersing device 46, the third liquid dispersing device in this order from the bottom). A liquid dispersion device 47 and a fourth liquid dispersion device 48) are installed. FIG. 2 is a longitudinal sectional view of the first liquid dispersion device 45 installed in the distillation column 40. The first liquid dispersion device 45 has a collector 71 at the top for collecting the liquid supplied from above at the center of the cross section of the distillation column 40. An inner cylindrical portion 72 for introducing the liquid collected by the collector 71 is installed below the center of the collector 71, and an outer cylindrical portion 73 provided with a gap between the inner cylindrical portion 72 and the outer cylindrical portion 72. Is installed. The lower part of the inner cylinder part 72 is connected to a lower dispersion pipe 74 made of a pipe that branches into a fishbone shape in a horizontal plane, and the lower part of the outer cylinder part 73 also has an upper dispersion pipe 75 having the same shape as the lower dispersion pipe 74. Connect with. Here, a plan view of the lower dispersion pipe 74 and the upper dispersion pipe 75 is shown in FIG. As shown in FIG. 3A, the lower dispersion pipe 74 is divided into a central pipe 77 corresponding to the backbone of the fishbone and five sides (10 on both sides) extending horizontally on the both sides at right angles to the central pipe 77. And branch pipe 78. Similarly, as shown in FIG. 3B, the upper dispersion pipe 75 includes a central pipe 79 corresponding to the backbone of the fishbone, and six pipes on one side (12 pipes on both sides) extending horizontally at right angles to the central pipe 79 on both sides. It consists of a branch pipe 80. The pores 76 and 81 are appropriately provided at the bottoms of the branch pipes 78 and 80. At this time, the pores 81 of the branch pipe 80 are arranged at positions that do not overlap the lower dispersion pipe 74 when viewed from below. Note that liquid dispersion devices other than the first liquid dispersion device 45 have the same configuration.

  A reflux line is provided at the top of the distillation column 40 to condense and return the purified product distilled from the top. In this reflux line, the first pipe 50, the purified product condenser 49, the second pipe 51, and the third pipe 52 are connected in this order, and the purified product from the top of the tower also flows in this order. An extraction line 53 for extracting the purified product condensed by the purified product condenser 49 is connected to a connecting portion 66 to which the respective ends of the second pipe 51 and the third pipe 52 are connected.

  In order to remove a small amount of low-boiling components contained in the waste solvent and recover the solvent as the main component, the third filler is placed between the uppermost fourth filler 44 and the third filler 43 below it. A second side cut port 55 and a first side cut port 54 are respectively provided on the side surface of the distillation column 40 between 43 and the second packing 42 below. Each side cut port is connected to a collection line 56. The recovery line 56 is provided with a solvent cooler 62 that cools the solvent distilled from each side cut port with cold water. The collection line 56 uses a pipe having an inner diameter larger than that of the extraction line 53, and can cope with a necessary processing amount. Further, the recovery line 56 on the upstream side (distillation tower 40 side) of the solvent cooler 62 and the connecting portion 66 in the reflux line are connected by a bypass line 58.

  The bottom of the distillation column 40 is connected to a reheating line 63, and the reheating line 63 is provided with a reboiler 59 that indirectly heats the liquid accumulated at the bottom of the distillation column 40 by the heat of steam. The second water vapor supply line 60 for sending water vapor to the reboiler 59 is connected not only to the reboiler 59 but also to the bottom of the distillation column 40 so that the water vapor can be supplied into the distillation column 40. A drain line 65 connected to the waste liquid tank is connected to the reheating line 63 at a position from the bottom of the distillation column 40 toward the reboiler 59. A drainage pump 61 is provided in the drainage line 65.

  An example in which a solvent is recovered from a waste solvent containing a solid component using the distillation apparatus according to the present embodiment having such a configuration will be described. In general, water is mixed in the waste solvent, but in the distillation apparatus according to the present embodiment, water may be mixed in the waste solvent. First, the waste solvent flows intermittently or continuously from the waste solvent supply line 11 into the evaporator 10. The waste solvent that has flowed into the evaporator 10 is heated by the heating unit 12 and concentrated as the solvent component evaporates. It is desirable to maintain the concentration of the solid component of the waste solvent in the evaporator 10 at 5 to 10%. However, when the solid component is non-adhesive, the concentration of the solid component may be 20 to 30%. . In addition, if water vapor | steam is directly supplied in the evaporator 10 from the 1st water vapor | steam supply line 13, since the temperature in the evaporator 10 will rise quickly, the start-up time of an apparatus can be shortened. Moreover, if water vapor | steam is directly supplied in the evaporator 10 in the case of a maintenance, the inside of the evaporator 10 can also be wash | cleaned.

  The waste solvent vapor evaporated in the evaporator 10 passes through the wire mesh demister 33 and is continuously sent to the distillation tower 40. In the wire mesh demister 33, since the mist accompanying the vapor is collected, the mist containing the solid component is blocked here.

  When the vapor entering the distillation column 40 passes through the insides of the first to fourth packings 41 to 44, a part of the steam is condensed by coming into contact with each packing and the liquid already attached to each packing. To do. At this time, since the inside of the distillation column 40 becomes hot at the lower position due to the vapor from the evaporator 10 or the vaporized by the reboiler 59, the high boiling point component of the vapor entering the distillation tower 40 is condensed by the low-position packing. However, the low boiling point component passes through without being condensed in the packing at the lower position and easily reaches the upper part of the distillation column 40.

  The vapor that has reached the top of the distillation column 40 enters the purified product condenser 49 through the first pipe 50 and is condensed by the cooling water flowing in the purified product condenser 49. A part of the condensate is refluxed to the upper part of the distillation column 40 through the second pipe 51 and the third pipe 52, and the other is recovered. If the waste solvent contains a component having a boiling point lower than that of the recovered solvent, the condensed product condensed in the refined product condenser 49 contains a large amount of the low boiling component, so the valve of the bypass line 58 is closed and the extraction line 53 is closed. Extract the condensate. At this time, the recovered solvent is recovered from the recovery line 56 via the first side cut port 54 or the second side cut port 55. On the other hand, when the waste solvent does not contain a component having a boiling point lower than that of the recovery solvent, the valve of the bypass line 58 is opened and the condensate condensed by the purified product condenser 49 is recovered via the recovery line 56. .

  The purified product which is easy to condense in the uppermost fourth packing 44 but easily passes through the third packing 43 below is extracted from the second side cut port 55. Similarly, the third filling 43 that is likely to condense but the second filling 42 below it is likely to pass through as steam and is extracted from the first side cut port 54. At that time, only the first side cut port 54 and the second side cut port 55 are opened, and the purified product is extracted. By providing a plurality of side cut ports in this way, the type of purified product to be recovered can be quickly changed simply by switching the opening and closing of the side cut ports, such as when the ratio of the solvent component of the waste solvent varies Operability is improved. Note that the liquid extracted from the first side cut port 54 and the second side cut port 55 flows through the recovery line 56 and is cooled and recovered by the solvent cooler 62.

  The liquid condensed in each packing in the distillation column 40 flows downward by gravity. Regardless of the amount of the liquid that flows down, the liquid is distributed and supplied to the entire upper surface of each filling material by the first to fourth liquid dispersing devices 45 to 48. This will be described with reference to FIGS. The liquid flowing down from the lower surface of the second filler 42 is collected in the center by the collector 71 and introduced into the inner cylindrical portion 72. The introduced liquid flows from the lower part of the inner cylindrical part 72 to the central pipe 77 of the lower dispersion pipe 74 and then branches to the branch pipe 78. The branched liquid flows downward from the pores 76 provided at the bottom of the branch pipe 78. When the amount of liquid supplied from the lower surface of the second filling 42 increases and the liquid overflows from the opening at the upper end of the inner cylindrical portion 72, the overflowed liquid is between the inner cylindrical portion 72 and the outer cylindrical portion 73. It flows into the gap. Like the lower dispersion pipe 74, the liquid flowing into the gap flows from the lower part of the outer cylindrical portion 73 to the central pipe 79 of the upper dispersion pipe 75, branches from there to the branch pipe 80, and reaches the bottom of the branch pipe 80. It flows out downward from the provided pores 81. At this time, since the pore 81 is provided at a position that does not overlap the branch pipe 78 when viewed from below, the liquid flowing out from the pores 76 and 81 flows down to a different position on the upper surface of the first filling 41. In this way, by providing two or more fishbone-shaped dispersion pipes, the liquid operating range is widened, and it becomes easy to cope with liquid load fluctuations. In general, the fishbone type dispersion pipe has a smaller liquid holding amount than the open channel type dispersion pipe, so that the product type can be switched quickly.

  The component that condenses in the first packing 41 located at the lowest position is a high boiling point component such as water, which is stored in a liquid state at the bottom of the distillation column 40. The accumulated liquid is sent to the reboiler 59 where it is indirectly heated to become steam, returns to the bottom of the distillation column 40, and rises in the distillation column 40. In addition, some high-boiling components are discharged to the waste liquid tank through the drain line 65.

  If water vapor is supplied from the second water vapor supply line 60 to the bottom of the distillation column 40 immediately after the start-up of the apparatus, the distillation column 40 is not waited for the vapor from the evaporator 10 to fill the distillation column 40. The internal temperature can be raised. Thereby, the time taken to start distillation can be shortened. Moreover, if water vapor | steam is directly supplied in the distillation column 40 in the case of a maintenance, the inside of the distillation column 40 can also be wash | cleaned.

  On the other hand, the waste solvent concentrated in the evaporator 10 is sent to the separation tank 20 through the waste solvent extraction line 14 in order to discharge the solid components. At this time, the opening / closing method of the waste solvent extraction valve 15 is appropriately changed according to the properties of the solid components contained in the waste solvent. For example, when the solid components are easily bonded to each other or have high adhesiveness, the waste solvent is removed while the waste solvent extraction valve 15 is opened intermittently by timer control in order to prevent the solid components from approaching each other. Let it flow down. Further, when the solid component tends to drift in the waste solvent, the waste solvent extraction valve 15 is slightly opened to allow the waste solvent to flow slowly and continuously. When the solid component adheres to the inner wall of the waste solvent extraction line 14 and the tube is blocked, compressed air is intermittently sent from the compressed air supply line 16 into the tube with the waste solvent extraction valve 15 closed. As a result, the solid component that has adhered is pushed away into the separation tank 20.

  Since the waste solvent that flows into the separation tank 20 is heated by the evaporator 10, a part of the waste solvent tends to become vapor when it flows into the separation tank 20. Since this vapor is condensed in the waste solution condenser 22 to become a liquid, it does not leak outside and pollute the atmosphere. The waste solvent accumulated in the separation tank 20 is settled and separated into a supernatant liquid containing no solid component and a slurry in which the solid component and the solvent component are mixed. The supernatant overflows from any one of the first to third supernatant outlets 25 to 27, and is sent to the temporary storage tank 29 through the supernatant outlet line 28. At this time, since there is a difference in the installation height of each supernatant liquid outlet, it corresponds to fluctuations in the amount of waste solvent flowing into the separation tank 20, or the concentration of solid components in the separation tank 20 is adjusted. You can do it. The supernatant liquid collected in the temporary storage tank 29 is pumped up by the pump 31 and returns to the evaporator 10 through the supernatant circulation line 30. At this time, the supernatant liquid can be discharged from the waste liquid line 34 to the waste liquid tank instead of being returned to the evaporator 10. On the other hand, the slurry accumulated at the bottom of the separation tank 20 is discharged to a drum can 21 provided below the separation tank 20 when the ratio of solid components in the separation tank 20 increases to a predetermined value (for example, about 70%). The In general, since the solid component contained in the waste solvent has a higher density than the solvent component, even if the solid component is likely to drift in the waste solvent, it settles by being left in the separation tank 20 for a while.

  The example which collect | recovered acetone which is the main component of the waste solvent from the waste solvent containing a solid component using the distillation apparatus which concerns on a present Example is demonstrated. The waste solvent used contained 86.6 wt% acetone, 12.9 wt% water, 0.5 wt% solid component having high tackiness such as resist, and 200 ppm methanol. First, the waste solvent was continuously supplied to the evaporator 10 at 431 kg / h, and liquid components (acetone, water, methanol) were vaporized while being heated by the heating unit 12. At this time, the waste solvent extraction valve 15 was closed. Continue heating for a while and concentrate the waste solvent. After the concentration of the solid component in the waste solvent reaches about 8 wt%, the waste solvent extraction valve 15 is opened and closed intermittently under the timer control to remove the concentrated waste solvent. It extracted into the separation tank 20 at a rate of 29 kg / h. The extracted waste solvent contained 33.4 wt% acetone, 59.0 wt% water, 7.6 wt% solid components, and 200 ppm methanol.

  In the separation tank 20, the extracted waste solvent was settled and separated into a supernatant and a slurry. The supernatant was discharged from the first supernatant outlet 25 and stored in the temporary storage tank 29, and then returned to the evaporator 10 by the pump 31. The slurry was extracted into the drum 21 when the concentration of the solid component reached 70 wt% by continuing the sedimentation separation in the separation tank 20 for a while.

  The vapor evaporated in the evaporator 10 was sent to the distillation column 40 through the vapor line 32 and separated. The recovered solvent containing a large amount of acetone was extracted from the second side cut port 55, cooled to 20 ° C. with a solvent cooler 62 disposed in the recovery line 56, and recovered. The content of each liquid in the recovered solvent was 99.85 wt% acetone, 0.15 wt% water, 30 ppm or less methanol, and the recovered amount was 347 kg per hour. Thus, a high proportion of 92.8% of acetone contained in the waste solvent supplied to the evaporator 10 could be recovered from the recovery line 56.

  The solvent that reached the top of the distillation column 40 was extracted from the extraction line 53. The content of each component in the extracted solvent was 99.6 wt% acetone and 0.4% methanol, and the recovered amount was 17 kg per hour. Further, 38 kg of water per hour was discharged from the bottom of the distillation tower 40 to the waste liquid tank through the drainage line 65.

1 is a schematic configuration diagram of a distillation apparatus according to an embodiment of the present invention. Longitudinal sectional view of the first liquid dispersion device 45 installed in the distillation tower 40 A plan view of the lower dispersion pipe 74 (a) and a plan view of the upper dispersion pipe 75 (b)

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Evaporator 11 ... Waste solvent supply line 12 ... Heating part 13 ... 1st water vapor supply line 14 ... Waste solvent extraction line 15 ... Waste solvent extraction valve 16 ... Compressed air supply line 20 ... Separation tank 21 ... Drum can 22 ... Waste solution Capacitor 23 ... Condensation line 24 ... Slurry extraction line 25 ... First supernatant outlet 26 ... Second supernatant outlet 27 ... Third supernatant outlet 28 ... Supernatant outlet 29 ... Temporary storage tank 30 ... Supernatant circulation line 31 ... Pump 32 ... Steam line 33 ... Wire mesh demister 34 ... Waste liquid line 35 ... Slurry extraction valve 40 ... Distillation tower 41 ... First packing 42 ... Second packing 43 ... Third packing 44 ... the fourth filling 45 ... the first liquid dispersion device 46 ... the second liquid dispersion device 47 ... the third liquid dispersion device 48 ... the fourth liquid dispersion device 49 ... the purified product capacitor 50 ... the first pipe 51 Second pipe 52 ... Third pipe 53 ... Extraction line 54 ... First side cut port 55 ... Second side cut port 56 ... Recovery line 58 ... Bypass line 59 ... Reboiler 60 ... Second steam supply line 61 ... Drain pump 62 ... Solvent cooler 63 ... reheating line 65 ... drainage line 66 ... connecting part 71 ... collector 72 ... inner cylinder part 73 ... outer cylinder part 74 ... lower dispersion pipe 75 ... upper dispersion pipe 76 ... pores 77, 79 ... central pipe 78 80 ... branch pipe 81 ... pore

Claims (14)

In a distillation apparatus that recovers a solvent component from a waste solvent containing a solid component,
An evaporator for heating the waste solvent to vaporize a solvent component;
A waste solvent line for draining the waste solvent from the evaporator;
A separation tank for receiving the waste solvent from the waste solvent line and settling and separating the waste solvent;
A supernatant line for returning the supernatant of the waste solvent settled and separated in the separation tank to the evaporator;
A distillation apparatus comprising:   2. The distillation apparatus according to claim 1, wherein the separation tank is provided below the evaporator, and one end of the waste solvent line is connected to the bottom of the evaporator.   The distillation apparatus according to claim 1, further comprising a flow rate adjusting unit for waste solvent flowing through the waste solvent line.   The distillation apparatus according to any one of claims 1 to 3, further comprising compressed air supply means for sending compressed air into a pipe of the waste solvent line.   The distillation apparatus according to any one of claims 1 to 4, wherein a plurality of supernatant outlets in the separation tank are provided at different height positions on the wall surface of the separation tank.   The distillation apparatus according to claim 1, further comprising a condensing unit that condenses the waste solvent vapor in the separation tank.   A heating unit that indirectly heats the waste solvent in the evaporator with the heat of water vapor, and a water vapor supply line that supplies water vapor to the heating unit appropriately supplies water vapor not only to the heating unit but also to the evaporator. The distillation apparatus according to any one of claims 1 to 6.   The distillation apparatus according to any one of claims 1 to 7, further comprising a solid component removing unit that prevents passage of solid components contained in the waste solvent at an outlet of the waste solvent vapor in the evaporator.   A distillation section that separates waste solvent vapor flowing from the evaporator using a difference in boiling point, and the distillation section includes a side cut port for distilling a purified product by a side cut method. Item 9. The distillation apparatus according to any one of Items 1 to 8.   The distillation apparatus according to claim 9, comprising a plurality of the side cut ports, and distilling the purified product from different temperature ranges in the distillation section. A reflux line for condensing the purified product distilled from the upper part of the distillation part and returning it to the distillation part;
A recovery line for cooling and recovering the purified product distilled from the side cut port;
A bypass line for sending the purified product condensed in the reflux line to the recovery line;
The distillation apparatus according to claim 9 or 10, comprising:   A distillation unit that separates waste solvent vapor flowing in from the evaporator by utilizing a difference in boiling point, and a liquid dispersion unit that supplies and supplies a liquid supplied from above downward in the distillation unit. The distillation apparatus according to claim 1, wherein: The liquid dispersing means is
A collector that collects liquid supplied from above and flows downward;
An inner cylindrical portion that is provided below the collector and introduces liquid collected by the collector;
An outer cylinder provided outside the inner cylinder with a gap between the inner cylinder and the inner cylinder;
A plurality of lower branch pipes connected to the lower part of the inner cylinder part and branched in a horizontal plane are provided at the bottom of the lower branch pipe by introducing a liquid flowing inside the inner cylinder part A lower dispersion tube for flowing liquid from the pores;
A plurality of upper branch pipes connected to the lower part of the outer cylinder part and branched in a horizontal plane, and the upper branch pipe is introduced by introducing a liquid flowing in a gap between the outer cylinder part and the inner cylinder part An upper dispersion pipe for flowing the liquid from the pores provided at the bottom of
The distillation apparatus according to claim 12, comprising:   A distillation unit that separates waste solvent vapor flowing from the evaporator by utilizing a difference in boiling point; and a reheating unit that indirectly heats the liquid accumulated at the bottom of the distillation unit by the heat of water vapor. The distillation apparatus according to any one of claims 1 to 13, wherein a water vapor supply line for supplying water vapor to the heating means appropriately supplies water vapor not only to the reheating means but also to the bottom of the distillation section.

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