JPH0796093B2 - Device to recover solvent from solvent gas - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recovering a solvent from a solvent gas used for recovering a solvent in a washing machine or the like used in various manufacturing industries. In the present invention, the gas includes mist-like gas or vapor-like gas.

[0002]

2. Description of the Related Art Conventionally, the above-mentioned device is generally formed as shown in FIG. In the figure, a is a container, which is, for example, a cleaning tank, in which the solvent b is contained. Reference numeral c is a work insertion port, and d is a work ejection port. Then, cover e on top of the container a
Is formed, and the suction pipe f is opened in the cover e. h is a suction device, i is a solvent using activated carbon b
The recovery device of FIG. j is the gas of the solvent b mixed with air. A work (not shown) is inserted through the insertion port c,
It is washed with the solvent b and taken out from the outlet d, during which the suction device h is operated, and the gas j of the solvent b mixed with air is sucked from the opening g of the suction pipe f. It is sucked together with the inflow air from both ports c and d, sent to the collecting device i, and collected by the device i.

[0003]

However, the above-mentioned conventional apparatus generally has the following problems. That is, the suction device h must suck a large amount of air and always consumes a large amount of power. Another problem is the recovery device i
Is to be large. This is because a large-capacity recovery device using activated carbon is required in order to concentrate a solvent gas having a relatively low concentration at a high magnification. In addition, the phenomenon of deterioration of the quality of the recovered solvent is observed, in which the oxidation of the solvent is promoted during the adsorption and desorption of the activated carbon, and the component composition of the stabilizer added to the solvent is partially destroyed. This leads to deterioration of the recovery device and inevitably requires high cost. The present invention has been made to solve the above problems, and its purpose is to suck a gas with an extremely small amount of air, and thus use less power than the device described in the conventional example, from solvent gas to solvent. It is to provide a device for recovering.
Still another object is to provide a relatively small and compact device for recovering solvent from solvent gas. Still another object is to provide an apparatus for recovering a solvent from a solvent gas which can achieve continuous operation without any trouble while achieving the above-mentioned objects.

[0004]

The present invention, which achieves the above-mentioned object, is described as follows: a container 1 containing a solvent; an inside 2 of the container 1 and below an upper edge 3 of the container 1, and A suction pipe 6 having a opening 5 at a position 4 above the liquid level of the solvent contained in the container 1 for sucking the gas of the solvent; a suction device 7 provided in communication with the suction pipe 6; A condenser 11 connected to the compression side of the device 7 and connected to a first tank 13; the first tank 1
3, a plurality of deep-cooling condensers 12 and 12 which are provided in communication with the upper part of the refrigerator 3 and are operated by a refrigerator 16;
3, which communicates with the plurality of deep-cooling condensers 12, 12 and has an upper portion 23a located above the liquid level of the solvent in the container 1 and below the opening 5 of the suction pipe 6. 5
a water separator 23 which is communicated with a, the lower part of which is communicated with the container 1 and which is communicated with the outside 23b from the middle in the height direction;
It is an apparatus for recovering a solvent from a container gas.

Further, the solvent container 1 has a heater 8 at a lower portion thereof, and a cooling device 9 is provided inside and above the liquid surface of the solvent.
Is an apparatus for recovering a solvent from the gas of the above solvent.

[0006]

First, an apparatus having only the suction pipe 6 in the container 1 for containing the solvent, that is, an apparatus having neither the heater 8 nor the cooling device 9, will be described.
The solvent 29 is stored in the container, and the work and the like are washed in the container 1. At that time, the gas of the solvent 29 is generated. In this case, when the suction device 7 and the condenser 11 and one of the plurality of deep-cooled condensers 12 and 12 are operated, that is, when suction is started, the gas is in the vicinity of the opening 5 of the suction pipe 6, It forms a horizontal vapor surface and is sucked while moving horizontally on the same surface. At the same time, a vapor zone is formed which is almost uniform and has a high concentration between the vapor surfaces from the liquid surface. This behaves as if it were half a liquid overflow. The formation of the vapor surface suppresses the upward diffusion. And
In this case, in particular, the suction air volume may be a small air volume. By the way, assuming the same scale recovery device, the conventional activated carbon method is 1
Compared with the case where the air flow rate of 0 m ³ / minute unit was required, according to the method, the same effect can be obtained with the air flow rate of 100 liter / minute unit. In addition, in a similar suction example with a small air volume, there is a method of utilizing natural suction by cooling condensation, but this alone is insufficient for diffusion suppression, and a suction with an appropriate small air volume is necessary.

Further, according to such a suction method, the gas of the solvent sucks the gas on the vapor surface having a much higher concentration than that shown in the conventional example, and therefore, the concentrated adsorption is performed by using the activated carbon. Even if it is not performed, it can be recovered by the condensation method. Therefore, the apparatus can be made smaller than the method using activated carbon. Next, in the case where the container 1 has the heater 8 and the cooling device 9, the solvent 29 in the container 1 is heated and used for cleaning or the like, and becomes a gas and evaporates in the process. In this case, when the cooling device 9 is operated, the gas comes into contact with the cooling device 9 to adhere and coagulate to become a liquid, which is dropped and collected. In this case, the vicinity of the cooling device 9 is made to have a negative pressure, whereby the gas of the solvent in the vicinity is attracted, brought into contact with the cooling device 9 and liquefied.

As a result, the gas on the surface or the negative pressure is successively moved horizontally, and as a result, a vapor zone having a vapor surface is naturally formed. This is called a first vapor surface and a first vapor zone. Here, when the recovery device 10 is operated, the diffusion vapor from a part of the first vapor surface forms the second vapor surface and the second vapor zone in such a form that the liquid surface is seen from the first vapor surface. . It serves to suppress the diffusion of a large amount of heated steam from the first and second vapor surfaces. In this case as well, in the same manner as described above, a high-concentration gas is sucked with a small amount of air, and therefore this does not need to be concentrated using activated carbon, only the condensation is required, so that the recovery device is small and compact. Can be formed into Next, as described above, the suction of the solvent gas is performed on the vapor surface, or as a result of this suction, another problem as described below occurs. It is unavoidable that the air in contact with the vapor surface is also sucked in, and if the deep-cooled condensers 12, 12 connected to the refrigerator 16 are used for almost complete recovery, freezing of water vapor in the air will occur. Therefore, the deep-cooled condensers 12 and 12 have a drawback that the entire apparatus cannot operate continuously.
The present invention solves the above drawbacks and provides an apparatus capable of sucking a solvent gas from a vapor surface and recovering the solvent gas almost completely, and capable of continuous operation. That is, a plurality of deep-cooled condensers 12 and 12 connected to the refrigerator 16 are provided in communication with the first tank 13 of the condenser 11, and a water separator 23 is provided in communication with the first tank 13. The upper part 23a of the water separator 23 is located above the liquid level of the solvent in the container 1 and below the opening 5a of the suction pipe 6 at a position 5a.
And the lower part is communicated with the container 1 and is communicated with the outside 23b from the middle of the height direction, so that only one of the plurality of deep-cooled condensers 12 and 12 is operated, When freezing of water vapor occurs on one side, the one deep-cooling condenser 12 is stopped and the other deep-cooling condenser 12 is operated to thaw the freezing on the one deep-cooling condenser 12. The above operations of the both 12 and 12 are alternately performed so that continuous operation is performed. Also, a water separator 23 communicating with the first tank 13 and the plurality of deep-chill condensers 12, 12.
The solvent gas collected in the upper portion 23a of the container 1 is supplied to the vapor zone of the container 1 and is condensed again with the solvent gas of the container 1. Further, the solvent of the water separator 23 is fed into the container 1, the water accumulated in the water separator 23 is separated by specific gravity separation, and is discharged to the outside from the communicating portion 23b, which makes difficult continuous operation. It can be carried out.

[0009]

1 to 3, reference numeral 1 denotes a container, which is, for example, a cleaning tank, and a suction pipe 6 having an opening 5 is provided at a position 4 inside the container 2 and below an upper edge 3 thereof. It is provided. Reference numeral 7 indicates a suction device. 2 and 3, reference numeral 8 is a heater provided in the container 1, and 9 is a cooling device. The cooling device 9 is a pipe formed in a coil shape, and cold water flows through the pipe. Next, in FIG. 3, a compressor was used as the suction device 7 for sucking the gas of the solvent and compressing it for condensing in the next stage.

Next, the condensing mechanism comprises a water-cooled condenser 11 and a plurality of deep-cooled condensers 12, 12. The condenser 11 is formed in combination with a compressor as the suction device 7, is compressed and condensed by the compressor and the condenser 11 to be liquefied, and flows into the first tank 13. In addition, 14 and 15 are an inlet and an outlet of the cooling water, respectively, through which the cooling water is flowing during the operation of the condenser 11. Next, one of the deep-cooled condensers 12 and 12 is operated, and the other is stopped. One of them is cooled to -40 ° C by the refrigerator 16, for example, and the gas of the solvent is condensed and liquefied in the fins 17 and the like, and a part thereof is solidified. Therefore, it is stopped in a certain time cycle, and the other deep-cooling condensation is operated, and the deep-cooling condenser 12 is thawed and liquefied by using the heat generated by the freezing operation from the refrigerator 16 The gas is dropped and stored in the second tank 18.

In the solvent recovery device 10, most of the solvent gas is recovered in the water-cooled condenser 11 and the rest is recovered in the deep-cooled condenser 12. Reference numeral 19 is a pulsation prevention tank, and 20 is a safety valve. Next, 21 is a pressure switch, 22 is a pressure gauge, 23 is a water separator,
Reference numeral 24 represents a circulation pump. Next, 25 is an optional device, which is an adsorption device using activated carbon. Usually, this device 25 is not necessary, but it is provided when a very small amount of loss is a problem, and therefore a very small device is sufficient as compared with the conventional activated carbon adsorption device. 26
Is a hot air generator, 27 is a relief valve, and 28 is a solenoid valve. Further, 29 indicates a solvent.

Next, in the operation of the above-structured apparatus as described above, the heights of the liquid surfaces of the suction pipe 6 and the solvent 29 are variously changed, and the intake air amount is changed to change the amount of the solvent to be sucked. A test was done to see the changes. This test was performed using the solvent at room temperature using the equipment shown in Fig. 1 (Table 1).
And a solvent (Table 2) was used as a hot bath using a heater 8 and a cooling device 9 as shown in FIG.
The results are shown in Table 1 and Table 2, respectively.
And in this case, the opening of the container 1 is 0.5 square meters.
Further, the tube height in the table refers to the height from the liquid surface to the opening 5, and the air volume refers to the suction air volume of the suction device 7. In addition, the numerical value in the frame obtained by the experiment is the recovery amount of the solvent per hour, and the unit is × 300 cc in both Table 1 and Table.

[0013]

[Table 1]

[Table 2]

As can be seen from this table, the amount of solvent recovered is larger as it is closer to the liquid surface, and becomes larger as the amount of suction air increases. However, it can be seen that at a certain height or more, the value becomes a constant value regardless of the suctioned air volume. This means that the more the forced suction force is increased, that is, the air volume is increased, and the lower the suction port is, the more the supply of the solvent vapor from the bottom is increased. It shows that the same amount of steam as the large air volume is captured. Therefore, in the static state, that is, in the state where the cleaning work does not move, the inlet position may be high, but in the dynamic state where the realistic work is moving, the vapor in the tank does not show a linear concentration gradient. , Because it is in a very disturbed state and promotes transpiration outside the machine,
It is desirable to suck at the liquid level or a height close to the first vapor surface. That is, a small amount of air and high-concentration suction are the most appropriate suctions. Next, the operation of the apparatus according to this embodiment will be described. As the solvent, Freon R113 was used as an example, and the operation of the suction apparatus is as described in the above description of the operation, or the heater 8 shown in FIG. In the device having the cooling pipe 9, as shown in FIG.
The second vapor surfaces 30, 31 are generated. The first vapor surface 30 is located below the cooling device 9 and the second vapor surface 31 is
Occur on top of the cooling device 9. This phenomenon was discovered as a result of experiments. The first vapor zone 32 below the first vapor surface 30 is, for example, Freon R113.
When it is used, it is about 1,000,000 PPm. The second vapor zone 33 below the second vapor surface 31 is approximately 50
It is about 10,000 PPm. Then, in the space 34 on the second vapor surface 31, it becomes approximately several tens to several hundreds of PPm. The relationship between the first and second vapor surfaces and the concentration of the solvent gas is shown in FIG.

Even in the apparatus shown in FIG. 1 which does not have the heater 8, a vapor zone 35 having a concentration of the second vapor zone and a vapor surface 36 of the second vapor surface are formed during the suction action. Thereby, the gas of the solvent having a high concentration can be sucked. Next, most of the sucked gas is liquefied in the compressor and the condenser 11 of the suction device 7, and a slight residue thereof is chilled condenser 1.
It is liquefied in 2 and pumps 24 through the water separator 23.
Is returned to the container 1. Therefore, it does not matter if the adsorption device 25 using activated carbon is not provided, but if desired, it can be installed as an option.

[0016]

Since the present invention is constructed as described above, the solvent gas can be sucked with a small air volume and a high concentration.
The power of the suction device can be greatly reduced as compared with the conventional one. Moreover, the power of the recovery device can be reduced.
Further, for the same reason, since it is not necessary to concentrate and adsorb the gas by the conventional device such as activated carbon, a large-capacity adsorbing device is not required, and it can be simply recovered by compression condensation.
Therefore, the device can be made small and compact.
Further, as another effect, since the recovery is performed only in the process of condensation, the quality of the recovered solvent is remarkably superior to the conventional method of recovering using activated carbon, and the solvent can be recycled as it is. Next, according to the present invention, a plurality of deep-cooling condensers 12, 12 connected to the refrigerator 16 are provided in communication with the first tank 13 of the condenser 11 as described above, and also communicated with the first tank 13. A water separator 23 is provided, and an upper portion 23a of the water separator 23 is communicated with a position 5a which is higher than the liquid surface of the solvent in the container 1 and lower than the opening 5 of the suction pipe 6, and By connecting the lower part to the container 1 and communicating 23b to the outside from the middle in the height direction, only one of the plurality of deep-cooling condensers 12 and 12 is operated, and one of the deep-cooling condensers 12 When freezing occurs, the one deep-cooling condenser 12 is stopped, the other deep-cooling condenser 12 is operated, and the freezing of the one deep-cooling condenser 12 is thawed. The continuous operation is performed by alternately performing the above-described operations of the both 12 and 12. Also, the first tank 1
The solvent gas collected in the upper part 23a of the water separator 23 communicating with the three and the plurality of deep-chill condensers 12, 12 is supplied to the vapor zone of the container 1 and is condensed again with the solvent gas of the container 1. Can be put in. Further, the solvent of the water separator 23 is fed into the container 1, the water accumulated in the water separator 23 is separated by specific gravity separation, and is discharged to the outside from the communicating portion 23b, which makes difficult continuous operation. It can be carried out. That is, in order to effectively suck the gas from the vapor surface to recover the solvent, the suction of the air layer containing the steam in contact with the vapor surface is prevented, which causes icing, which makes it difficult to perform the connecting operation. You can

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention and schematically showing a solvent recovery device using a gas suction device.

FIG. 2 is a view corresponding to FIG. 1, showing another embodiment of the present invention.

FIG. 3 is a detailed view of FIG.

FIG. 4 is a diagram showing the relationship between the first and second vapor surfaces and the concentration of the solvent gas.

FIG. 5 is a diagram showing an outline of a conventional device of the same type.

[Explanation of symbols]

 1 Container 2 Inside 3 Upper Edge 4 Position 5 Opening 6 Suction Pipe 7 Suction Port 8 Heater 9 Cooling Device 10 Recovery Device

Claims (2)

[Claims] 1. A container 1 for containing a solvent; an inside of the container 1.
2 and lower than the upper edge 3 of the container 1, and
Open at position 4 above the level of the solvent contained in container 1.
A suction pipe 6 having a mouth part 5 for sucking a solvent gas;
Suction device 7 provided in communication with the drawing tube 6; the suction device 7
Communicating with the first tank 13 connected to the compression side of the
Condenser 11; installed in communication with the upper part of the first tank 13
Refrigerator 16 operated by a refrigerator 16
12, 12; communicate with the first tank 13 and
Several deep-cooled condensers 12, 12 and the upper part 23a is
The suction pipe 6 is located above the liquid level of the solvent in the container 1 and
To the position 5a which is lower than the opening of the
It is connected to the container 1 and is connected to the outside from the middle in the height direction.
A water separator 23 made to pass through 23b;
A device that recovers solvent from solvent gas. 2. The solvent container 1 has a heater 8 at the bottom.
The contractor that has the cooling device 9 inside and in the height direction.
The apparatus for recovering a solvent from a solvent gas according to claim 1.