JP2567541B2 - Solvent recovery device - Google Patents

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 quinylene.

[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]

In the conventional apparatus, since a small amount of solvent is contained in the separated water separated by the separator, the separated water is discharged to the outside of the system (river). It must be treated below the regulation value according to the wastewater standard. Therefore, a wastewater treatment device for separated water, for example, an aeration tank or the like 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, according to the first aspect of the present invention, there is provided a steam generator in which an electric heating coil for superheating and an electric heating coil for steam generation are arranged below a solvent adsorption tower, And while providing a condenser in the adsorption tower,
A specific gravity separator connected to the condenser is provided, a gas containing solvent vapor is introduced into the adsorption tower from above to adsorb the solvent vapor, and the vapor is blown from the vapor generator to desorb the adsorbed solvent. In the device, the specific gravity separator is provided by connecting a separation water tank via a pipe, the separation water tank is provided by connecting to a steam generator via a pipe provided with a valve, these pipes, a separation water tank, The separated water from the specific gravity separator is supplied to the steam generator through a valve and piping.
According to a second aspect of the present invention, in the first aspect, a heating pipe for overheating is provided instead of the heating coil for overheating, and a heating pipe for steam generation is provided instead of the heating coil for steam generation.

According to the invention of claim 3, two solvent adsorption towers are provided,
Each of these adsorption towers is provided with a condenser provided individually or as a common one, and a common steam generator in which a steam superheating coil and a steam generation heating coil are arranged above and below the adsorption tower is provided. Connected and provided, a shared specific gravity separator is provided connected to the condenser, and a separated water tank is connected to this specific gravity separator via a pipe, and the separated water tank is provided via a pipe provided with a pump. Is connected to the steam generator, and the separated water from the specific gravity separator is supplied to the steam generator through these pipes, separation water tank, pump, and pipes, and exhaust from one outlet of the adsorption tower When the concentration of the solvent to be used exceeds a predetermined value, the operation of one of the adsorption towers can be stopped and the operation of the other adsorption tower can be started.

[0007]

[Operation] As described above, the separated water from the specific gravity separator is piped,
The separated water is supplied to the steam generator again because it is supplied to the steam generator through the separated water tank, the valve, and the pipe or through the pipe, the separated water tank, the pump, and 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 manner, 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, and is condensed while passing through a passage in the outer pipe constituting the condenser in a countercurrent direction 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) thus separated enters the separated water tank 18 through the pipe 17, and then 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. Thus, even if the separated water is circulated, 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.
Are installed in parallel, and one specific gravity separator 50 and one steam generator 51 are installed in common for these adsorption towers. That is, the specific gravity separator 50 is connected to the condensers 10 of the first and second adsorption towers 1 and 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 reference numeral 65 denotes a steam generation chamber in the steam generator 51, in which a steam superheating coil 66 and a steam generation heating coil 67 as electric heaters are vertically arranged. I have. 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 mixture (solvent and water) is sent to a separator 50 via a pipe 53, separated into a solvent and separated water by specific gravity separation, and the solvent is recovered in a 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 alone is insufficient, replenish industrial water as make-up 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. The steam generator 85 is provided with a steam superheating pipe
A steam generator boiler 86 supplies steam to both pipes via 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 instead of the steam generator 5 provided below the adsorption tower 1 in FIG.

[0022]

Since the inventions of claims 1 and 2 are constructed as described above, they have the following excellent effects. (1) Since the separated water is supplied to the steam generator to be heated and circulated as steam, a wastewater treatment device for draining the separated water becomes unnecessary, and the equipment cost can be greatly reduced. Moreover, at this time, the separated water supplied to the steam generator can be entirely converted into steam by the steam generating electric heating coil of the steam generator, and it is not necessary to separately discharge the separated water to the outside. (2) Since a trace 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 separation water is always constant and does not increase. Therefore, continuous circulation of the separated water can be used (that is, continuous desorption operation can be performed), and corrosion of the steam generator and the piping is small. (3) Since the separated water containing a trace amount of the solvent separated by the specific gravity separator is heated by the steam generator, not only one having a boiling point of the solvent lower than that of water but also one having a higher 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. According to the invention of claim 3, in addition to the above, the adsorption treatment can be further performed 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 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. 2;

FIG. 4 is an enlarged view of a main part showing another example of the steam generator corresponding to FIG. 2;

[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 (3)

(57) [Claims] 1. A vapor generator (5) having an electric heating coil (7) for superheating and an electric heating coil (8) for steam generation arranged above and below the solvent adsorption tower (1), and condensed on the adsorption tower. A vaporizer (10) is provided, a specific gravity separator (16) connected to the condenser is provided, and a gas containing a solvent vapor is introduced into the adsorption tower (1) from above to adsorb the solvent vapor and generate a vapor. In a solvent recovery device for desorbing the adsorbed solvent by blowing steam from the vessel (5), a separation water tank (18) is connected to the specific gravity separator (16) via a pipe (17), and the separation water tank is provided. Valve (2
0) is connected to the steam generator (5) via a pipe (19), and the specific gravity is passed through these pipes (17), separated water tank (18), valve (20) and pipe (19). A solvent recovery device, characterized in that the separated water from the separator (16) is supplied to the steam generator (5). 2. The heating pipe for overheating (88) is provided instead of the heating coil for overheating (7), and the heating pipe for steam generation (89) is provided instead of the heating coil for steam generation (8). The solvent recovery device described. 3. A vapor superheat coil (6) comprising two solvent adsorption towers (1) and a condenser (10) provided in each of these adsorption towers or provided as a common one.
6) and a steam generating heating coil (67) arranged vertically are connected to a common steam generator (51) connected to the lower part of each adsorption tower (1), and a common specific gravity separator (50) is provided to the condenser. (10)
The specific gravity separator (50) is connected to the pipe (6
1) A separation water tank (60) is connected to the separation water tank via a pipe (6) provided with a pump (64).
It is provided by connecting to the steam generator (51) via the pipe (61), the separated water tank (60), and the pump (6).
4), the separated water from the specific gravity separator (50) is supplied to the steam generator (51) via the pipe (62), and the solvent discharged from one outlet of the adsorption tower (1) When the concentration exceeds a predetermined value, the operation of one of the adsorption towers is stopped, and the operation of the other adsorption tower (1) is started so that the solvent recovery apparatus can be switched.