JPH0122633Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention is based on perchlorethylene, trichlorethylene, 1,
1,1, relates to a recovery device for dry cleaning solvents such as trichloroethane. [Prior Art and Issues] Conventionally, for example, in the dry cleaning method of clothing, etc. using perchlorethylene as a solvent, most of the perchlorethylene remaining on the clothing after cleaning is removed by a circulating system equipped with a drum, a water-cooled condenser, and a heater. Circulate and collect air through the circuit,
After this, a deodorizing treatment was carried out to remove the small amount of perchlorethylene that remained in the clothing and emitted an odor. Conventional deodorizing treatment involves slightly opening the door of the dry cleaning drum or opening the outside air intake and activating the blower used for collection, leading the odor to the exhaust duct and releasing it into the atmosphere. This method involves flowing fresh air into the drum to replace the solvent-containing air in the drum and also replacing the solvent-containing air in the clothes. However, this method has the disadvantage of causing a loss of solvent escaping into the atmosphere through the exhaust duct, and discharging the solvent into the atmosphere is undesirable from a sanitary and pollution standpoint. As a countermeasure to this problem, a method has been proposed in which the exhaust gas is led to an activated carbon recovery device to adsorb the solvent, and steam is supplied to the activated carbon recovery device as needed to recover the solvent. However, in this activated carbon recovery device, the running cost is approximately proportional to the amount of solvent adsorbed, and the running cost is required for a constant solvent gas load on the dry cleaner side. Therefore, in order to solve the above-mentioned problems, a solvent recovery method as shown in FIG. 2 was proposed. This device is a dry cleaning device that can be used not only for perchlorethylene or trichlorethylene but also for other solvents, especially low boiling point solvents such as 1,1,1, trichloroethane. In the drying process, air in a dry cleaning machine (hereinafter referred to as dry cleaner) 1 is circulated by a first blower 2 through a water-cooled condenser 3 and a heater 4 to a drum 5, thereby condensing and recovering the solvent. At this time, the dampers 6 and 7 are closed. (Position of the two-dot chain line). Next, in the deodorizing process, the dampers 6 and 7 are opened (solid line position), and the fresh air flowing into the system from the opening of the damper 7 passes through the chamber 10 containing the second blower 8 and the refrigeration coil 9 to the atmosphere. released. Here, the refrigeration coil 9 is connected to a refrigeration device 11, and the surface of the refrigeration coil 9 is maintained at an even angle of -20°. Deodorization is performed by condensation on the surface of 9. In addition, 12 in the figure is a dust filter, and 13 is a solvent tank. However, if we take the case where the inlet gas temperature of the refrigeration coil is 20℃ and the outlet temperature of the same is 0℃, as shown in Figure 3, the refrigeration coil inlet gas concentration gradually changes over time as shown by the broken line a. The gas concentration at the outlet of the refrigeration coil gradually decreases as shown by the solid line b, but the recovered portion c is only the shaded area, and as time passes, the reevaporation portion d in the refrigeration coil 9 (range shown by dots)
occurs, and the portion below the solid line b becomes the uncollected portion e. Therefore, the recovery rate of the solvent increases by only 0.7% at most compared to the case where the solvent is discharged outside the system without employing a refrigeration system. This is because fresh air is taken into the system, which dilutes the solvent gas concentration and significantly reduces the collection efficiency in the refrigeration coil 9. At the same time, the once condensed solvent evaporates again due to the fresh air, leaving the system outside the system. This is due to the fact that it is discharged into the body. This is particularly noticeable when 1,1,1, trichloroethane, which is a low boiling point solvent, is used as the solvent. As a result, a high concentration of solvent is still released into the atmosphere, which poses an air pollution problem and increases solvent loss and costs. The present invention has been made in view of the above circumstances, and aims to provide a dry cleaning solvent recovery device that can improve the solvent recovery rate, reduce solvent loss, and prevent air pollution. [Means for Solving the Problems] The present invention involves putting laundry into a washing drum installed inside a dry cleaner, washing, rinsing, and removing liquid while rotating the drum, and discharging the used solvent. Furthermore, in a dry cleaning solvent recovery device that recovers the solvent remaining in drums and laundry, there is a circulation path each equipped with a blower, a water-cooled condenser, and a heater, and a system that condenses and separates the solvent gas into a solvent liquid and a gas component. a first duct having an exhaust port that connects an outlet of the washing drum provided downstream of the water-cooled condenser in the circulation path and an inlet of the freezing recovery device via a control valve; A second air intake port connecting the inside of the drum and the outlet of the cryo-recovery device via a control valve.
duct, the solvent is condensed and recovered by the water-cooled condenser, and the solvent is further condensed and recovered by a combination of the water-cooled condenser and the frozen recovery device, and then
Bypassing the frozen recovery device, the first and second
This is a dry cleaning solvent recovery device characterized by supplying and discharging fresh air into a washing drum through a duct. [Function] According to the present invention, after the solvent gas is sufficiently condensed and recovered in the freezing recovery device, the device is bypassed and fresh air is circulated, thereby preventing re-evaporation of the solvent and reducing solvent loss. It has a remarkable effect in preventing air pollution. Embodiments of the present invention will be described below with reference to the drawings. [Example 1] FIG. 1 shows a dry cleaning solvent recovery device, which is similar to the conventional device shown in FIG. A damper 6, a dust filter 12, a solvent tank 13, etc. are provided. Furthermore, this device additionally has an outlet 5 of the washing drum 5.
a and the inlet part 21a of the frozen recovery device 21 are connected via the first duct 22, and the outlet part 21b of the frozen recovery device 21 is connected to the inside of the washing drum 5 and the second duct 24.
are connected via. The refrigerant recovery device 21 has a built-in regenerator cooler 25, which is connected to a refrigerator 26 through a refrigerating circuit 27 to cool the regenerator to about -20°C. Further, the upper chamber 21c of the frozen recovery device 21 is formed with the inlet portion 21a, and the first duct 22 attached thereto has control valves 28 and 29 inserted therein. One control valve 28 is connected to the inlet section 21.
The other control valve 29 opens and closes the exhaust port 29a to communicate and block the outside of the machine and the inside of the first duct 22. The upper chamber 21c
is connected to the washing drum 5 via a pipe 31 having a valve 30. The outlet section 21b is formed in the lower chamber 21d of the frozen recovery device 21, and the second duct 24 attached thereto is equipped with control valves 33 and 34. Here, one control valve 33 controls opening and closing of the outlet section 21b, and the other control valve 34 opens and closes the fresh air intake port 34a to communicate and block the outside of the machine and the inside of the second duct 25. It is something to do. A condensate collection device 35 is provided in the lower chamber 21d, and is connected to a water separator 36. Next, using the above recovery device, 1,
1. An example of a method for recovering a solvent using trichloroethane will be explained. First, the cleaning and deliquification process, which is the previous process of the solvent recovery process, will be explained. In this step, the damper 6 is closed (double-dashed line), the control valves 28, 29, 33, and 34 are closed, and the valve 30 is closed.
is in an open state, and in this state pre-processes such as washing, dewatering, and rinsing are performed. Here, drum 5
The internal pressure within the drum 5 may increase as the air expands inside the drum and the vapor pressure of the solvent increases. However, the solvent gas is sent to the regenerator cooler 25 via the piping 31 and condensed and recovered. There is no leakage to the outside of the system, and the internal pressure within the drum 5 is maintained approximately equal to atmospheric pressure. This also applies to the following drying process. Next, a drying step is performed to recover the solvent, but this step is performed in two stages. In the first stage process, the damper 6 and the control valve 28,
29, 33, and 34 are closed, the valve 30 is opened, and the water-cooled condenser 3, heater 4, and blower 2 are operated, and in this state, the solvent is condensed and recovered by the water-cooled condenser 3. In this case, even when a chiller (not shown) is connected to the water-cooled condenser 3 and the temperature of the cooling water inlet to the water-cooled condenser 3 is lowered to about 10°C, the outlet temperature of the air after passing through the water-cooled condenser 3 is at most 20 to 22°C. Stable at around ℃. Therefore, the vapor pressure of 1,1,1, relichloroethane at this time is 100 mm
The solvent gas in the drum 5 corresponding to Hg and the unevaporated content in the clothing that is in equilibrium with this are not recovered in this step. In this process, the temperature at the outlet of drum 5 is generally controlled (set at 50℃), although it depends on the air volume.
It will finish in 5-6 minutes. After this step is completed, a second stage solvent recovery step is performed. In this process, the damper 6 opens (solid line position),
Control valves 28, 33 and valve 30 are opened, control valves 29, 34 are closed (fresh air intake port 34a and exhaust port 29a are closed), water-cooled condenser 3 and blower 2 are operated, heater 4 is stopped, In this state, condensation and recovery by the regenerator cooler 25 is performed. In this case, the condensate condensed in the regenerator 25 passes through the condensate collection device 35 and flows into the water separator 36, after which the solvent is recovered. By setting the refrigeration capacity and air volume so that the air temperature at the inlet of the regenerator cooler 25 is 20°C and the outlet temperature is 0 to -2°C,
1,1,1, vapor pressure of trichloroethane 32-36mm
This will reduce the solvent gas concentration to a concentration equivalent to Hg. The time required for this step is determined by the above-mentioned refrigeration capacity and air volume, but is usually about 6 minutes. In addition, in this process, the washing drum 5,
A circulating air volume that is 10 to 30 times the total volume of the regenerator cooler 25 system is required, and a blower may be additionally installed in the first duct 22 if necessary. After this step, a deodorizing step is performed. In this step, the damper 6 is opened, the control valves 28 and 33 are closed, the control valves 29 and 34 are opened (the fresh air intake port 34a and the exhaust port 29a are open), the valve 30 is closed,
Stop water cooling condenser 3 and heater 4, and blower 2
is operated, and in this state, fresh air is supplied into the washing drum 5 from the second duct 24, bypassing the regenerator cooler 25, and is exhausted outside the machine via the first duct 22. According to the first embodiment, the solvent recovery rate is significantly improved by using the water-cooled condenser 3 and the regenerator cooler 25 in combination. That is, after the solvent gas is sufficiently condensed and recovered by recovery using the water-cooled condenser 3 and recovery using the water-cooled condenser 3 and regenerator cooler 25,
Fresh air can be circulated by bypassing the regenerator cooler 25. Therefore, the regenerator cooler 25
The condensed solvent will no longer evaporate again, and the recovery rate of the solvent will be significantly improved. Furthermore, by improving the recovery efficiency, the concentration of solvent gas released outside the system can be reduced to 32 to 36 mmHg or less. Further, since the amount of solvent loss can be easily calculated from the air temperature at the outlet of the control valve 33, that is, the air temperature at the outlet of the regenerator cooler 25, it is possible to prevent solvent loss with high accuracy. [Example 2] In this example 2, when the capacity of the regenerator type cooler 25 is small, a chiller is also used. That is, by using this chiller in combination, the water-cooled condenser 3
The cooling water inlet temperature is lowered to 1 to 2°C to increase the solvent recovery rate in the first stage recovery process, and then the second stage recovery process is performed with the water-cooled condenser 3 stopped. In this case, even if the water-cooled condenser 3 is stopped, the temperature of the clothing drops rapidly, and the evaporation of the solvent from the clothing is suppressed, resulting in a final recovery rate that is lower than in Example 1 but improved compared to the conventional method. [Embodiment 3] In this embodiment 3, the air inlet from the second duct 24 to the washing drum 5 is connected to the front part of the heater 4 (the A part shown in the figure). As a result, in the second stage drying process, the circulating air is heated by preheating the heater 4 and supplied to the clothing, so that the solvent is expelled from the clothing and condensed and recovered by the regenerator cooler 25. Therefore, according to Example 3, as shown in Table 1, the solvent loss rate is lower than in Example 1 as well as in Example 2. Incidentally, it goes without saying that the heater 4 may be operated. Note that when the capacity of the regenerator cooler 25 is sufficiently large (that is, when it has a capacity equivalent to the recovery by the water-cooled condenser 3), the piping 31 is abolished or kept in a stationary state, and the control valve 33 is kept open except during the deodorizing process. By doing so, it is also possible to use a means in which internal pressure fluctuations within the drum are quickly absorbed, and the condensation and recovery of the solvent in the drying process is performed only by the regenerator cooler 25. As a result, recovery efficiency similar to that of the above embodiment can be obtained, and the entire apparatus can be simplified. Of course, a refrigeration system alone may be used instead of a regenerator cooler. In addition, regenerator cooler 2
Dry cleaner 1
Of course, the same effect can be obtained even if it is integrated into the system. Next, Examples 1 to 3 described above were conducted under the conditions shown in Table 1 of the attached sheet, and the amount of recovered solvent and solvent loss were measured. The results are also shown in Table 1. Furthermore, the amount of solvent recovered and the solvent loss were also measured for the conventional method shown in FIG. 2, and the results are also listed in Table 1.

【table】

[Table] "Next, the first stage drying" was changed to 6 to 8 minutes, and the "second stage drying" was changed to 6 to 8 minutes.
"Stage drying" was reduced from 6 minutes to 4 minutes, "deodorization" was reduced from 2 minutes to 1 minute, "drying time" of the conventional method was reduced from 6 minutes to 8 minutes, and "air temperature at the outlet of the refrigeration coil and regenerator cooler" was reduced to 0. Table 2 shows the measurement results when the temperature was changed from -2°C to -10 to -20°C.

[Table] [Effects of the invention] As described above, according to the invention, after the solvent gas is sufficiently condensed and recovered in the freezing recovery device, the device is bypassed and fresh air is circulated, thereby preventing re-evaporation of the solvent. It is possible to provide a dry cleaning solvent recovery device that can reduce solvent loss and prevent air pollution.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a dry cleaning solvent recovery device showing an embodiment of the present invention, Fig. 2 is an explanatory diagram of a conventional dry cleaning solvent recovery device, and Fig. 3 is an explanatory diagram of the dry cleaning solvent recovery device. FIG. 3 is a characteristic diagram showing the relationship between the gas concentration and the gas concentration. 1... Dry cleaner, 2... First blower, 3
... Water-cooled condenser, 4 ... Heater, 5 ... Drum, 5a ... Discharge port, 6, 7 ... Damper, 8 ...
2nd blower, 9... Refrigeration coil, 10... Room, 1
1... Refrigeration device, 12... Dust filter, 13...
Solvent tank, 21... Refrigeration recovery device, 21a...
Inlet part, 21b... Outlet part, 21c... Upper chamber,
21d...lower chamber, 22...first duct, 24...
...Second duct, 25...Regenerator cooler, 26...
Refrigerator, 27... Refrigeration circuit, 28, 29, 33,
34...Control valve, 34a...Fresh air intake, 3
5... Condensate collection device, 36... Water separator.

Claims (1)

[Scope of utility model registration request] Laundry is placed in a washing drum installed inside the dry cleaner, and the drum is rotated to wash, rinse, and remove liquid. After discharging the used solvent, the solvent remaining in the drum and laundry is recovered. In dry cleaning solvent recovery equipment,
A circulation path provided with a blower, a water-cooled condenser, and a heater, a refrigeration recovery device for condensing and separating solvent gas, solvent liquid, and gas components, and a washing drum discharge port provided downstream of the water-cooled condenser in the circulation path. a first duct having an exhaust port that connects an inlet to a frozen recovery device via a control valve; and a fresh air intake that connects the inside of the washing drum and an outlet of the frozen recovery device via a control valve. and a second duct having a second duct, the water-cooled condenser condenses and recovers the solvent, and the water-cooled condenser and the frozen recovery device are used together to condense and recover the solvent, and then the first duct bypasses the frozen recovery device. - A dry cleaning solvent recovery device characterized by supplying and discharging fresh air into the washing drum through a second duct.