JP2024003611A - Distillation apparatus - Google Patents

Abstract

To provide a distillation apparatus which suppresses bumping of a solvent containing a foreign matter and can reduce lowering of quality of a regenerated solvent, when the solvent is recovered and regenerated by distillation.SOLUTION: A distillation apparatus 100 includes: a distillation pot 1 provided with a supply port 1a and an exhaust port 1b of a liquid solvent 5; a heating coil 2 which is installed below the distillation pot 1 and heats and evaporates the liquid solvent 5; and a gap holding member 6 that is arranged below the distillation pot 1 together with the heating coil 2 and of which at least a part has a height immersed in the liquid solvent 5.SELECTED DRAWING: Figure 1

Description

The present invention relates to a distillation apparatus for regenerating a solvent used as a cleaning liquid for processed products such as various mechanical parts.

Since various machining oils are used in machining machine parts, etc., it is necessary to wash the workpiece to remove the machining oil. Conventionally used cleaning liquids include organic solvents such as alcohols, glycol ethers, and hydrocarbons.

Examples of methods for cleaning objects to be cleaned (workpieces) using solvents include immersion cleaning, in which the workpiece is immersed in a solvent stored in a cleaning tank, and solvent vapor is brought into contact with the workpiece that has been cleaned with the solvent. Steam cleaning that involves drying is known. Since these cleaning solvents contain foreign matter such as oil, it is preferable from the environmental and resource-saving standpoints to remove foreign matter, regenerate, and use the solvent repeatedly after use.

When using a flammable solvent, a high boiling point solvent, a highly volatile solvent, etc. as a cleaning liquid, the recovery and regeneration of the solvent is generally performed by distillation. Distillation is performed by placing a heating coil at the bottom of the distillation pot, passing a heating medium (such as heating oil) through this heating coil to heat the used solvent stored in the distillation pot, and discharging it from the top of the distillation pot. The solvent vapor thus produced is condensed by a condenser to regenerate the solvent.

However, since the solvent used for cleaning contains foreign substances such as oil, as the solvent evaporates through distillation, the concentration of foreign substances such as oil in the remaining solvent increases, making bumping of the solvent more likely to occur. When such bumping occurs, foreign matter is likely to be mixed into the solvent vapor, resulting in a decrease in the quality of the recycled solvent.

In order to suppress the mixing of foreign matter into the solvent vapor, multiple rectifying plates (baffle plates) are usually placed above the liquid level of the solvent stored in the still, and if necessary, a rectifying plate is installed. A demister made of metal mesh is placed above the plate.
Patent Document 1 discloses that the upper part of the electric heater disposed at the lower part of the evaporating pot is raised above the level of the liquid solvent, and the diameter of the coil is increased to form a bubble extinguishing section, thereby suppressing the foaming of the solvent. A distillation regenerator is described in which even if bumping occurs, it can be brought into contact with a defoaming section and extinguished.

However, although the conventionally proposed distillation regenerator can suppress the mixing of foreign substances into the solvent vapor to some extent, it does not suppress bumping of the solvent, so there is a risk that foreign substances will mix into the solvent vapor.

Japanese Patent Application Publication No. 2001-46801

An object of the present invention is to provide a distillation apparatus that can suppress bumping of a solvent containing foreign substances and reduce deterioration in the quality of the recycled solvent when recovering and regenerating a solvent by distillation.

The distillation apparatus of the present invention for solving the above problems is for separating and removing foreign substances from the liquid solvent by vaporizing a liquid solvent containing foreign substances, and is provided with a supply port and an exhaust port for the liquid solvent. a distillation pot; a heating section installed in the distillation pot for heating and evaporating a solvent; and a void retaining member disposed below the distillation pot and having a height such that at least a portion thereof is immersed in the liquid solvent. and.

According to the present invention, bumping of the liquid solvent can be suppressed by the void retaining member placed at the bottom of the distillation pot and immersed in the liquid solvent, thereby suppressing the deterioration of the quality of the recycled solvent and enabling precision distillation. This makes it possible to improve solvent regeneration efficiency.

1 is a configuration diagram showing a distillation apparatus according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line A-A in FIG. 1. FIG. FIG. 2 is a partial plan view showing an example of a mesh material used as a gap retaining member in the present invention. FIG. 2 is a partial plan view showing an example of a punching material used as a gap retaining member in the present invention.

A distillation apparatus according to an embodiment of the present invention will be explained based on FIGS. 1 to 4. As shown in FIG. 1, the distillation apparatus 100 includes a distillation pot 1 provided with a solvent supply port 1a and an exhaust port 1b. The supply port 1a is for supplying the liquid solvent 5 containing foreign matter into the distillation pot 1, and is provided at the lower part of the distillation pot 1. Further, the exhaust port 1b is for discharging the vaporized solvent, and is provided at the upper part of the distillation pot 1, for example, at the top.

The distillation pot 1 is made of metal such as stainless steel, for example, and has an outer peripheral surface covered with a heat insulating material or the like. Inside the distillation pot 1, a heating coil 2 (heating section), a plurality of rectifier plates 3, and a demister 4 are provided in order from the bottom. The liquid solvent 5 is normally supplied into the distillation pot 1 to a height at which the heating coil 2 is immersed therein.
Distillation may be performed under normal pressure or under reduced pressure. When performing under reduced pressure, the degree of vacuum is preferably -80 kPa or more and -99 kPa or less.

The liquid solvent 5 is, for example, a solvent used as a cleaning liquid in a cleaning tank or a rinsing tank in a cleaning device for machine parts, etc., and the solvent contains foreign substances such as oil generated during cleaning and rinsing. The distillation apparatus 100 separates such a solvent from foreign substances and regenerates and recovers it. Examples of the solvent include organic solvents such as alcohols, glycol ethers, and hydrocarbons, including flammable solvents, high boiling point solvents, and highly volatile solvents. Note that the foreign matter is not limited to oil, but also includes components with a higher boiling point than the liquid solvent 5.

The heating coil 2 heats and vaporizes the liquid solvent 5 by passing a heating medium therein, and is formed by winding a heating medium pipe into a coil shape to form a cylindrical shape. As the heating medium, for example, oil such as mineral oil or silicone oil, steam, heated water, etc. are used. The heat medium is supplied from a heat medium supply port 2a at one end of the heating coil 2, and is discharged from a heat medium discharge port 2b at the other end. Moreover, the heating coil 2 may be a coil-shaped electric heater.

As shown in FIGS. 1 and 2, a heating coil 2 and a gap retaining member 6 are arranged at the bottom of the distillation pot 1. That is, the heating coil 2 has a cylindrical shape as a whole, and the gap retaining member 6 is located between the outer peripheral side of the heating coil 2 and the distillation pot 1, as shown in FIG. It includes a gap retaining member 6a and an inner gap retaining member 6b disposed on the inner peripheral side of the cylindrical heating coil 2. Note that the gap holding member 6 only needs to include at least one of the outer gap holding member 6a and the inner gap holding member 6b.
The outer gap retaining member 6a and the inner gap retaining member 6b are arranged around the entire circumference or a part of the heating coil 2.

Examples of the gap retaining member 6 include a mesh material, a punching material, and the like. As the mesh material, for example, as shown in FIG. 3, a metal mesh material in which metal wires 7 of stainless steel or the like are woven into a mesh shape can be used. A material similar to the wire mesh material used as No. 4 can be used. The demister 4 generally collects and separates foreign substances (impurities) entrained in the vapor flow using lines within a wire mesh, and is disposed at the upper part of the distillation pot 1 as shown in FIG.

The metal wire 7 constituting the mesh material preferably has a wire diameter of 0.1 mm or more, preferably 0.5 mm or more, and 1.5 mm or less, preferably 1.0 mm or less. Further, the mesh material is preferably 3 meshes or more, preferably 5 meshes or more, and 15 meshes or less, preferably 12 meshes or less. The mesh refers to the number of metal wires 7 within 1 inch (2.54 cm) and represents the density of the mesh material.
It is preferable that the mesh material is arranged and accommodated in the lower part of the distillation pot 1 in a state where a plurality of mesh materials are stacked one on top of the other or folded multiple times. By overlapping or folding, the void retaining member 6 has a large number of voids throughout, and has a large void ratio (space ratio) and a large surface area. The number of overlapping or folding of the mesh material is not particularly limited, and for example, it is sufficient to overlap at least 3 sheets or fold at least 3 times.If the mesh material is overlapped or folded more than that, the voids will increase more. Therefore, it is more preferable.

Further, the punching material used as the gap retaining member 6 is, for example, a metal plate 8 made of stainless steel or the like in which a large number of through holes 9 are formed, as shown in FIG. As the punching material, for example, one in which the diameter d of the through holes 9 is 0.5 to 3 mm, the pitch p is 1 to 5 mm, and the aperture ratio is 10 to 30% can be used. Here, the aperture ratio refers to the proportion of the through hole 9 portion punched out by punching to the entire portion. Note that the shape (circular, rectangular, rhombic, etc.) and arrangement of the through holes 9 are not particularly limited.
Similar to the above-mentioned mesh material, such punching material is placed and housed in the lower part of the distillation pot 1 in a state where a plurality of sheets are stacked or folded several times. Therefore, by stacking or folding, the void retaining member 6 has a large number of voids throughout, and has a large void ratio (space ratio) and a large surface area.

At least a portion of the gap retaining member 6 in this embodiment is immersed in the liquid solvent 5. Thereby, even if the liquid solvent 5 in the distillation pot 1 reaches its boiling point, unexpected bumping can be suppressed. Therefore, the entrainment of foreign matter in the solvent vapor distilled from the upper part of the distillation vessel 1 due to bumping is reduced, and deterioration in the quality of the recycled solvent can be effectively prevented.
Although the mechanism by which bumping of the liquid solvent 5 is suppressed by the void retaining member 6 is not clear, it is presumed that the fact that the void retaining member 6 has many voids is involved.

In FIG. 1, the void retaining member 6 is entirely immersed in the liquid solvent 5, but it may have a height such that at least a portion thereof is immersed in the liquid solvent 5. That is, the void retaining member 6 may be installed at the bottom of the distillation pot 1, and its upper end may protrude above the liquid level 5a of the liquid solvent 5, or may be located below the liquid level 5a of the liquid solvent 5. It's okay. Specifically, the height of the void holding member 6 from the bottom is 30% or more of the height from the bottom of the distillation pot 1 to the liquid level 5a of the liquid solvent 5 (the liquid level before boiling). preferably 50% or more (may exceed 100%).
Note that the void holding member 6 may be installed at the bottom of the distillation pot 1 via a spacer (not shown) instead of being installed directly at the bottom of the distillation pot 1, or it may not be in contact with the bottom of the distillation pot 1. You can also hang it from above like this.

In this embodiment, in order to improve gas-liquid separation performance, multiple stages of rectifying plates 3 are arranged above the liquid level 5a of the liquid solvent 5 (FIG. 1). Each rectifier plate 3 is composed of a horizontal shelf board (tray), and openings 3a are formed between each rectifier plate 3 and the distillation pot 1 in alternating directions.
Further, as the current plate, a current plate (not shown) provided with a large number of through holes may be used.

Further, if necessary, a demister 4 made of wire mesh or the like may be provided above the current plate 3. Thereby, the separation action (fractional distillation) can be performed more effectively.

The solvent vapor distilled from the upper exhaust port 1b of the distillation pot 1 is condensed into a liquid solvent in a condenser (not shown). The obtained liquid solvent is, for example, sent to a cleaning tank as a regenerated cleaning liquid and used for circulation. Further, the distilled solvent vapor can be used as it is for steam cleaning of parts and the like.

Next, an evaluation test was conducted on the distillation apparatus 100 in which the void retaining member 6 was installed at the bottom of the distillation pot 1, and the results are shown below.

(Test example 1)
Table 1 shows distillation apparatuses A, B, and C used in the test.
The distillation apparatus C corresponds to the distillation apparatus 100 of this embodiment shown in FIGS. 1 and 2, except that it does not include the demister 4. As the void retaining member 6, a mesh material made of stainless steel (SUS304) with a wire diameter of φ0.8 mm x 10 mesh was used, and a plurality of mesh materials were stacked one on top of the other and filled on the inner and outer circumferential sides of the heating coil 2, respectively. .
Both distillation apparatuses A and B do not have the void retaining member 6 (mesh material) in the distillation apparatus 100 of this embodiment, and distillation apparatus A further does not have the rectifying plate 3 and the demister 4. .

Mineral oil at 150° C. was used as the heating medium of the heating coil 2, the degree of vacuum in the distillation pot 1 was -90 kPa, and the heater for heating the heating medium was 15 kW.
The evaluation used Aqua Solvent GF (registered trademark, isoparaffinic hydrocarbon manufactured by Aqua Chemical Co., Ltd.) containing 5% by mass of oil as a solvent, and measured the amount of distillation regeneration (L/hour) and the regenerated solvent after distillation. The oil content was investigated. The results are also shown in Table 1. In Table 1, "〇" means yes, and "-" means no.

From Table 1, when using distillation apparatus A that does not have the rectifier plate 3, demister 4, or void retaining member 6, bumping occurs, oil is detected in the recycled solvent after distillation, and the quality of the solvent deteriorates. Ta.
If distillation apparatus B, which does not have the void retaining member 6, is used, bumping will occur, but since the solvent is separated from the oil by the baffle plate 3 and demister 4, the recycled solvent after distillation will require more than distillation apparatus A. Oil content was reduced.
On the other hand, when using the distillation apparatus C having the void retaining member 6 (mesh material) and the rectifying plate 3 (three stages), almost no oil is detected in the recycled solvent after distillation, and the amount of distillation recycled is also small. It was good.

(Test example 2)
Distillation was carried out in the same manner as in the distillation apparatus C of Test Example 1, except that a punching material with a through hole 9 having a hole diameter d of 1.5 mm, a pitch of 3 mm, and an aperture ratio of 22.7% was used instead of the mesh material as the void retaining member 6. Device D was created. The punching material is made of stainless steel (SUS304).
As a result, the distillation regeneration amount was 67L/hour, and the oil content before distillation was less than 0.001% by mass compared to 5% by mass before distillation, and almost no oil was detected in the recycled solvent after distillation. There wasn't.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications and improvements can be made within the scope of the present invention. For example, in the above embodiment, the rectifying plate 3 and the demister 4 are placed in the distiller 1 along with the mesh material 6, but as in the distiller C used in the evaluation test, the mesh material 6 and the rectifying plate 3 are A similar effect can be obtained by a combination or by simply arranging only the mesh material 6. Further, the heating section is not limited to the heating coil 2, and other heating devices may be used. For example, it may be a jacket that covers the outer circumferential surface of the heating pot 1 and allows the heating medium to pass therethrough, or a jacket that has an electric heater built therein.

1 Distillation pot 1a Supply port 1b Exhaust port 2 Heating coil (heating section)
2a Heat medium supply port 2b Heat medium discharge port 3 Current plate 3a Opening 4 Demister 5 Liquid solvent 5a Liquid level 6 Mesh material 7 Metal wire 8 Metal plate 9 Through hole 100 Distillation device

Claims (7)

a distillation pot equipped with a liquid solvent supply port and a solvent vapor exhaust port;
a heating section installed in the distillation pot for heating and evaporating the liquid solvent;
A distillation apparatus comprising: a void retaining member disposed below the distillation pot and having a height such that at least a portion thereof is immersed in the liquid solvent. The heating section is a heating coil installed at a lower part of the distillation pot, and the gap retaining member includes an outer gap retaining member disposed between an outer peripheral side of the heating coil and the distillation pot; The distillation apparatus according to claim 1, comprising one or both of an inner gap retaining member disposed on the inner peripheral side of the coil. The distillation apparatus according to claim 2, wherein the outer gap retaining member and the inner gap retaining member are arranged around the entire circumference or a part of the heating coil. The distillation apparatus according to any one of claims 1 to 3, wherein the void retaining member is formed from a mesh material or a punching material. 5. The distillation apparatus according to claim 4, wherein the mesh material or the punching material is arranged in a state in which a plurality of sheets are overlapped or folded multiple times at the lower part of the distillation pot. The distillation apparatus according to any one of claims 1 to 3, wherein a rectifying plate is disposed above the distillation pot. The distillation apparatus according to claim 4, wherein a demister is arranged above the rectifying plate.

Images