JPH0623230A - Solvent recovery apparatus - Google Patents

Abstract

PURPOSE:To provide a solvent recovery apparatus which dispenses with a waste water treatment device for separated water separated by a separator and curtails operating cost. CONSTITUTION:A steam generator 5 is installed in the lower part of a solvent adsorber 1 and a condenser 10 is installed in the adsorber. A gravity separator 16 connected to the condenser is provided and solvent vapor-contg. gas is introduced into the adsorber 1 from above to adsorb the solvent vapor and steam is blown in from the steam generator 5 to desorb the adsorbed solvent. There are provided a piping 17, a separated water tank 18 and a piping 19 for feeding the separated water (waste water) from the gravity separator 16 to the steam generator 5 and a makeup water pipe 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic solvent generated from a solvent vapor generating section such as dry cleaning, metal washing, fiber washing, etc., particularly water-insoluble organic solvent such as trichlorethylene, perchlorethylene, trichlorethane,
The present invention relates to an apparatus suitable for recovering a solvent such as Freon 113, toluene, and kynren.

[0002]

2. Description of the Related Art As a conventional solvent recovery device of this type, there is a device disclosed in Japanese Utility Model Publication No. 54-1475 proposed by the applicant of the present invention.

[0003]

By the way, in this conventional apparatus, since the trace amount of solvent is contained in the separated water separated by the separator, this separated water is discharged to the outside of the system (river). It must be treated below the regulation value according to the wastewater standards. Therefore, a wastewater treatment device for separated water, such as an aeration tank, is required. In addition, since the amount of separated water is large, there is a problem that the equipment becomes large-scale equipment and the operating cost is high.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and to provide a solvent recovery apparatus which does not require a waste water treatment apparatus for separated water and can be operated at a low cost.

[0005]

In order to achieve the above object, a solvent recovery apparatus of the present invention is provided with a vapor generator below a solvent adsorption tower, a condenser provided in the adsorption tower, and a condenser. Provided with a specific gravity separator connected to, adsorbing solvent vapor by introducing gas containing solvent vapor from above into the adsorption tower, in a solvent recovery device for desorbing the adsorbed solvent by blowing vapor from the vapor generator, A pipe is provided to supply the separated water from the specific gravity separator to the steam generator. The steam generator is composed of an overheating electric heating coil and a steam generating electric heating coil arranged above and below. In this case, a heating pipe for overheating may be provided instead of the heating coil for overheating, and a heating pipe for steam generation may be provided instead of the heating coil for steam generation.

Further, the solvent recovery apparatus of the present invention comprises two solvent adsorption towers and a condenser provided in each of these adsorption towers or as a common one, and a common steam generator is provided. Provided in connection with the lower part of each of the adsorption towers, a shared specific gravity separator is provided in connection with the condenser, and a pipe for supplying separated water from the specific gravity separator to the steam generator is provided, the adsorption tower When the concentration of the solvent exhausted from one of the outlets exceeds a predetermined value, the operation of the one adsorption tower is stopped and the operation of the other adsorption tower is started.

[0007]

Since the pipe for supplying the separated water from the specific gravity separator to the steam generator is provided as described above, the separated water is supplied again to the steam generator through the pipe. Although a small amount of solvent is also contained in the supplied separated water, it is sent to the adsorption tower together with the steam by heating by the steam generator to be desorbed and is not discharged to the outside of the system. Further, even if the separated water is circulated in this way, the solvent itself evaporates, so that the solvent does not increase in the steam generator.

[0008]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention. Reference numeral 1 denotes an adsorption tower, which is installed on the leg portion 2 by accommodating the adsorbent a of the activated carbon tower therein. 3 is a dust filter, 4 is a fan connected to the dust filter 3, and this fan 4 is installed in communication with the upper space of the adsorbent a accommodated in the adsorption tower 1.

Reference numeral 5 denotes a steam generator directly connected to the lower part of the adsorption tower 1. The steam generator 5 has a housing 6, and an upper heating electrothermal coil 7 is provided in the upper space of the housing 6. An electric heating coil 8 for steam generation is arranged in the water.

A condenser 10 composed of an inner and outer double pipe is wound around the upper periphery of the adsorption tower 1. The inner tube of the condenser 10 is provided with an inlet 11 for supplying cooling water and an outlet 12 for discharging water. One end of the outer pipe is connected to an introduction pipe 13 opened in the upper space of the adsorbent a housed in the adsorption tower 1, and the other end is a drain pipe.
Connected to 14. 16 is connected to drain pipe 14 and adsorption tower 1
The separator 16 is provided with a specific gravity separator, and a separator water tank 18 is connected to the separator 16 via a pipe 17, and the lower portion of the tank is a valve.
It is connected to a makeup water pipe 21 connected to the casing 6 of the steam generator 5 via a pipe 19 having 20.

Reference numeral 25 is a gas introducing damper, 26 is an air exhausting damper, and 27 and 28 are temperature controllers. The temperature controller 27 has a steam generating electrothermal coil 8 which is always underwater exposed on the water surface in case of an accident. The temperature controller 28 is provided so as to switch off the coil when the power is turned on while the coil is turned on or off when the heating coil 7 for overheating becomes below or above the set temperature. Has been. 30 is the case 6
A water level gauge for maintaining the water level in the inside at a constant water level, 31 is a solenoid valve, 32 is an exhaust pipe, and 33 is a solvent extraction pipe.

The operation of the above embodiment will be described. Damper 25,
26 is opened, and the raw gas containing the solvent vapor is introduced into the dust filter 3 by the activation of the fan 4. The raw gas is supplied with static air pressure by the fan 4 into the adsorption tower 1 and the adsorbent a The solvent vapor in the gas is adsorbed by the adsorbent a while passing through the exhaust gas, and the air purified by this is released into the atmosphere through the exhaust pipe 32.

After the adsorbent a has adsorbed a predetermined amount, the dampers 25 and 26 are closed, and the steam generated in the casing 6 of the steam generator 5 is sent to the adsorbent a, whereby the adsorbent a is adsorbed. The used solvent is desorbed.

The desorbed solvent vapor and water vapor are introduced into the introduction pipe 13
Is guided to the condenser 10 via, is condensed while passing through the passage in the outer pipe constituting the condenser in the countercurrent with the cooling water, becomes a liquid and flows into the separator 16 through the drain pipe 14, Here, they are separated by the difference in specific gravity. At this time, cooling water flows in through the inlet 11 to cool the solvent vapor and water vapor, and is discharged through the outlet 12.

The solvent separated in the separator 16 is recovered from the conduit 33, and the separated water (drainage) separated is introduced into the separated water tank 18 through the pipe 17, and then through the pipe 19 and the makeup water pipe 21. It is supplied into the housing 6 of the steam generator 5. Therefore, even a trace amount (20-200ppm) of solvent contained in the separated water,
The adsorption tower 1 together with steam by heating with the steam generator 5
It will not be released to the outside of the system by being sent to and detached from. Even if the separated water is circulated in this way, the solvent itself evaporates, so that the solvent does not increase.

When the desorption is completed, the dampers 25 and 26 are opened, the fan 4 is activated and the cooling gas (generally the atmosphere) is introduced, and the adsorbent a is dried and cooled.

2 to 3 show an adsorption tower 1 having the same structure as described above.
2 is installed in parallel, and one specific gravity separator 50 and one steam generator 51 are installed in common in these adsorption towers. That is, the specific gravity separator 50 is provided so as to be connected to the condensers 10 of the No. 1 adsorption tower 1 and the No. 2 adsorption tower 1 by the pipes 53 and 54. It should be noted that each condenser 10 may be independent of each adsorption tower 1 and one may be shared by each adsorption tower. Further, a steam generator 51 is provided by being connected to the lower portions of the No. 1 adsorption tower 1 and No. 2 adsorption tower 1 by pipes 56 and 57.
A three-way valve 58 is installed at the connection of 56 and 57. Reference numeral 60 denotes a separated water tank, which is connected to the separator 50 by a pipe 61 and is connected to the steam generator 51 by a pipe 62. Reference numeral 64 denotes a pump installed in the pipe 62, and 65 in the steam generator 51 denotes a steam generation chamber, in which a steam superheating coil 66 as an electric heater and a steam generation heating coil 67 are vertically arranged. There is. 68 is a liquid level gauge (controller), 70 is a blanking prevention thermometer, and 71 is an overheat prevention thermometer.

Reference numeral 73 is a solvent recovery tank connected to the separator 50 by a pipe 74, 76 and 77 are exhaust pipes connected to the exhaust pipes 32 of the No. 1 adsorption tower 1 and No. 2 adsorption tower 1, and 78 is an exhaust pipe. Valves 80 and 81 are provided near the adsorption tower 1 in the cooling water supply pipe.
Reference numeral 83 is a cooling water return pipe, and 90 and 91 are drain pipes connecting the separation water tank 60 and the exhaust pipe 32 of the No. 1 adsorption tower 1 and the No. 2 adsorption tower 1. The No. 1 adsorption tower 1 and the No. 2 adsorption tower 1 can be alternately switched between running and stopping by a control member (not shown).

An example of the operation of this example will be described below. In this example, the raw gas containing the solvent is supplied into the No. 1 adsorption tower 1 through a duct filter (not shown) when the dampers 25, 26 of the No. 1 adsorption tower 1 are opened, and the fan 4 is activated. Only the solvent is adsorbed by the adsorbent a in 1 and the cleaned air is discharged into the atmosphere through the exhaust pipes 32 and 76. And 1
When the adsorption time by the adsorption tower 1 becomes long, the amount of the solvent in the adsorbent a increases, and the solvent is gradually exhausted from the outlet of the adsorption tower. The breakthrough point is 10% concentration), but before this breakthrough time, the control member stopped the operation of No. 1 adsorption tower 1,
Operation is switched to No. 2 adsorption tower 1. When the adsorption by the No. 1 adsorption tower 1 is completed, the solvent is desorbed from the adsorbent a, so that steam (105 ° C. to 110 ° C.) passes from the steam generator 51 through the pipe 56 and the three-way valve 58 to the No. 1 adsorption tower 1. Sent to. The steam and the solvent desorbed by the steam are cooled in the condenser 10 and liquefied. The liquefied mixed liquid (solvent and water) is sent to the separator 50 via the pipe 53, and is separated into the solvent and the separated water by specific gravity separation, and the solvent is recovered in the recovery tank 73 and reused. On the other hand, the separated water is sent to the separated water tank 60 via the pipe 61. This separated water contains a small amount of dissolved solvent.

The separated water in the separated water tank 60 is supplied to the steam generator 51 by the pump 64 through the pipe 62. Steam generator 51
Then, the separated water is evaporated by the steam generating heating coil 67 provided in the steam generating chamber 65 to generate superheated steam (105 ° C to 110 ° C). A small amount of solvent is also heated in the steam generation chamber 65, and is sent to the No. 1 adsorption tower together with water vapor for desorption.
When steam is generated in the steam generation chamber 65 and the liquid level is lowered, the pump 64 is activated by the liquid level gauge 68 to replenish the separated water in the separated water tank 60. If the separated water is insufficient, replenish industrial water as supplementary water. Incidentally, since a trace amount of residual solvent contained in the separated water is also heated and vaporized by the steam generator 50,
The solubility is always constant, and even if the separated water is circulated, the solvent of the separated water does not increase.

FIG. 4 shows another example of the steam generator. This steam generator 85 is equipped with steam superheat pipes at the top and bottom of the steam generation chamber 87.
88 and a steam generation pipe 89 are provided, and steam is supplied to the both pipes from a steam generator boiler 86 through a conduit. Then, the separated water is vaporized by the steam heating pipe 88 and the steam generating heating pipe 89. Such a steam generator 85 may be installed in place of the steam generator 5 provided in the lower part of the adsorption tower 1 in FIG.

[0022]

Since the inventions of claims 1 to 3 have the above-mentioned constitutions, they have the following excellent effects. (1) Since the separated water is supplied to the steam generator to be heated and circulated as water vapor, a wastewater treatment device for discharging the separated water is not required, and the facility cost can be drastically reduced. (2) Since a small amount of solvent remaining in the separated water is also heated by the steam generator, it is vaporized (solvent vapor) and circulated together with water vapor. Therefore, the solubility of the solvent remaining in the separated water is always constant and does not increase. Therefore, the separated water can be continuously circulated (that is, continuous desorption operation can be performed), and the steam generator and the piping are less corroded. (3) Since the separated water containing a trace amount of solvent separated by the specific gravity separator is heated by the steam generator, not only the solvent having a boiling point lower than that of water but also the solvent having a high boiling point can be used, and it can be applied to a wide range of solvents. (4) Since the separated water is converted to steam by the steam generator, severe temperature management is not required and operation becomes easy. (5) The structure is relatively simple and can be manufactured at low cost. In addition to the above, the invention of claim 4 can further perform adsorption treatment by alternate operation of two adsorption towers, thereby increasing the operation rate.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention.

FIG. 2 is a piping system diagram showing an example in which two adsorption towers are installed in parallel.

FIG. 3 is an enlarged view of a main part of FIG.

FIG. 4 is an enlarged view of an essential part showing another example of the steam generator corresponding to FIG.

[Explanation of symbols]

 1 Adsorption tower 3 Dust filter 4 Fan 5 Steam generator 7 Electric heating coil for overheating 8 Electric heating coil for steam generation 10 Condenser 16 Specific gravity separator 17, 19 Piping 18 Separation water tank 21 Make-up water pipe

Claims (4)

[Claims] 1. A steam generator is provided below a solvent adsorption tower,
Further, a condenser is provided in the adsorption tower, a specific gravity separator connected to the condenser is provided, and a gas containing a solvent vapor is introduced into the adsorption tower from above to adsorb the solvent vapor, and the vapor generator. A solvent recovery device for desorbing the adsorbed solvent by injecting steam from the device, comprising a pipe for supplying the separated water from the specific gravity separator to the steam generator. 2. The steam generator comprises a superheating electric heating coil and a steam generating electric heating coil which are arranged one above the other.
The solvent recovery device described. 3. The solvent recovery apparatus according to claim 2, wherein a heating pipe for overheating is provided in place of the heating coil for overheating, and a heating pipe for steam generation is provided in place of the heating coil for steam generation. 4. A solvent vapor adsorption tower comprising two solvent adsorption towers and a condenser provided in each of these adsorption towers or provided as a common one, and a common steam generator is connected to a lower portion of each of the adsorption towers. A common specific gravity separator is connected to the condenser, and a pipe for supplying the separated water from the specific gravity separator to the steam generator is provided and exhausted from one outlet of the adsorption tower. When the concentration of the solvent exceeds a predetermined value, the operation can be switched so that the operation of the one adsorption tower is stopped and the operation of the other adsorption tower is started.