JP2005329380A - Evaporation concentrator for aqueous waste liquid and aqueous cleaning device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problems: when waste liquid contains volatile oil, oil is contaminated in distillation wastewater of the conventional evaporation concentrator, and heat energy added for waste liquid evaporation increases the temperature of cooling water to be finally discharged. <P>SOLUTION: In this evaporation concentrator, oil-water separation unit is installed in a circulation circuit of the distillation wastewater, the volatile oil is separated, cooling water stored in a cooling water tank is circulated to the evaporation concentrator, and the resultant water is used as a hot water source, thereby high efficient heat recovery is carried out. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an evaporative concentration apparatus for concentrating an aqueous waste liquid under reduced pressure, and an aqueous cleaning apparatus for heating the cleaning liquid using the evaporative concentration apparatus or concentrating and processing the cleaning liquid.

Amid increasing interest in environmental issues, there is a need to reduce the environmental burden caused by the treatment of aqueous waste liquids. However, as the alternative cleaning method is attracting attention, a method for treating the waste liquid has become a problem.
Conventionally, it has been common for water-based waste liquids to be treated as industrial waste or treated to a water quality that can be discharged by providing a wastewater treatment facility. However, there is a problem that the cost burden increases when the amount of waste liquid is large in the processing consignment, and there is a problem that a large burden is required for installation, operation and management of the equipment when using the wastewater treatment facility.

Therefore, in recent years, as a small-scale waste liquid treatment method, an evaporative concentration apparatus for concentrating waste liquid in a decompressed evaporation tank and reducing the amount of waste liquid has been proposed.
For example, in Patent Document 1, the plating cleaning waste liquid is heated in a horizontally-placed cylindrical vacuum drying container in a reduced pressure state, and the evaporated water is cooled by a condenser to be distilled waste water (distilled water). The waste liquid is stored in the drying container. Concentrated.
Moreover, in patent document 2, a photographic processing waste liquid is heated and evaporated by the evaporation concentration column of a pressure reduction state, and is collect | recovered as a condensate by the cooling condensing part provided on it. A heat pump is used for heating the liquid and cooling the steam.
Japanese Patent Laid-Open No. 2003-211149 Japanese Patent Laid-Open No. 4-4085

However, in both cases of Patent Document 1 and Patent Document 2, when volatile oil (for example, volatile hydrocarbons having a boiling point of 30 to 40 ° C.) is contained in the waste liquid, the steam is cooled. Volatile oil is mixed into the obtained distilled effluent, and there is a problem that the quality of the distilled effluent is not suitable for drainage standards.
Moreover, in the method of patent document 1, the heat energy added in order to evaporate a waste liquid will eventually be discharged | emitted as the temperature rise of a cooling water, and has a problem from a viewpoint of the effective utilization of a heat energy. . In particular, in a waste liquid concentrating apparatus using an evaporation concentration method, most of the energy consumption of the apparatus is thermal energy required for water evaporation, and it is important to recover and reuse this.

On the other hand, in the method of Patent Document 2, the heat efficiency is improved because the heat pump is used for the heating means and the cooling means. However, the heat pump usually uses chlorofluorocarbon as a refrigerant, and further includes a compressor, a capillary, a heat exchanger, and the like. Since the mechanism used is required, the apparatus becomes complicated, and there are problems such as an increase in apparatus price and complicated control.
The present invention can separate and remove low-temperature volatile oil even if it is mixed in distilled wastewater, and can recover heat energy used for heating waste liquid with high efficiency without using a heat pump. An object of the present invention is to provide an evaporative concentration apparatus and an aqueous cleaning apparatus using the same.

  In order to achieve the above object, the inventors of the present invention have conducted intensive research, and as a result, an oil / water separation unit is provided in a circulation circuit for distilled waste water to separate volatile oil and make the water quality suitable for waste water. Found that it is possible, and that the cooling water stored in the cooling water tank is circulated to the evaporative concentrator and is used as a hot water source, so that heat can be recovered with high efficiency. I let you.

  A first aspect of the present invention is an aqueous waste liquid evaporating and concentrating apparatus (hereinafter also simply referred to as “evaporating and concentrating apparatus”), a heater as a heating means for the aqueous waste liquid, and a concentration for incorporating the heater and evaporating and concentrating the aqueous waste liquid. A cooling pipe for passing cooling water to cool and liquefy the steam generated in the concentrating chamber, a cooling chamber for storing the cooling pipe, an ejector for decompressing the concentrating chamber and the cooling chamber, and an ejector A water system comprising: a circulating pump for supplying circulating water to the water, a circulating tank for storing the circulating water, and an oil / water separation unit for separating, removing and adsorbing oil contained in the circulating water It is a waste liquid evaporation concentrator.

  A second aspect of the present invention is characterized in that a coalescer made of a lipophilic nonwoven fabric and / or an ultrafiltration membrane having a molecular weight cut-off of 5,000 to 300,000 is used in the oil-water separation unit of the first aspect. The water-based waste liquid evaporative concentration apparatus.

  According to a third aspect of the present invention, the cooling water tank for storing the cooling water in the first to second inventions, the cooling water pump for feeding the cooling water to the cooling pipe, and returning the heated cooling water to the cooling water tank again. The cooling water return pipe and the cooling water tank are replenished with a suction port for sucking cooling water to be sent to the cooling pipe, a return port for returning the heated cooling water to the cooling water tank, and the cooling water. It has a replenishment port and an outlet for taking out the cooling water, the suction port position and the supply port position are arranged below the return port position and the outlet position, and the cooling water in the cooling water tank is taken out from the outlet, Can be used as a hot water supply source.

  According to a fourth aspect of the present invention, the cooling water of the first to third aspects is soft water having a total hardness of 10 mg / L or less (equivalent to calcium carbonate) or / and electrolytic alkaline water having a pH of 8.0 to 12.0. The water-based waste liquid evaporative concentration apparatus.

  According to a fifth aspect of the present invention, in the water-based cleaning apparatus, the cleaning water before being used for cleaning is used as cooling water for the evaporative concentration apparatus in the first to fourth aspects, and the cooling water heated by the evaporative concentration apparatus is The water-based cleaning device is used as cleaning water for a cleaning device.

  According to a sixth aspect of the present invention, in the fifth aspect of the invention, the cleaning liquid of the aqueous cleaning apparatus is concentrated by the evaporation concentrating apparatus, and the cleaning apparatus is replenished with a new cleaning liquid to compensate for the cleaning liquid reduced by the concentration process. It is an aqueous cleaning device.

  According to the first aspect of the present invention, it is possible to perform the concentration process without using a heat pump in the aqueous waste liquid evaporation concentration apparatus, the apparatus can be simplified, and the apparatus cost can be reduced. Moreover, by providing an oil-water separation unit in the circulating water system, it becomes possible to remove volatile oil contained in distilled waste water, and the quality of waste water can be improved as compared with the conventional case.

  According to claim 2 of the present invention, by using a coalescer or an ultrafiltration membrane that can efficiently separate and remove oil emulsified in water, volatile oil contained in the wastewater is further removed, and the quality of the wastewater Can be improved.

  According to the third aspect of the present invention, it is possible to effectively use the thermal energy that has been conventionally discharged as the temperature rise of the cooling water, and the thermal energy efficiency of the entire system can be improved. Moreover, since this thermal energy recovery is performed without using a heat pump, the apparatus can be simplified and the apparatus cost can be reduced.

  According to the fourth aspect of the present invention, the scale of calcium or the like can be prevented from adhering to the inner surface of the cooling pipe of the evaporative concentration apparatus, so that the efficiency of heat recovery can be maintained at a high level. Further, corrosion of the metal cooling pipe can be prevented.

  According to the fifth aspect of the present invention, since the heat energy recovered from the evaporative concentration apparatus can be used for heating the cleaning liquid of the aqueous cleaning apparatus, the thermal energy of the heater used in the aqueous cleaning apparatus can be reduced. As a result, energy efficiency can be improved while the system does not use a heat pump.

  In the sixth aspect of the present invention, in addition to the effect of the fifth aspect, the cleaning waste liquid of the aqueous cleaning apparatus can be evaporated and concentrated, so that the processing cost and processing time of the cleaning waste liquid can be reduced.

  The best mode for carrying out the present invention will be described with reference to FIG. However, the present invention is not limited to these embodiments.

  The concentration chamber 1 for evaporating and concentrating the aqueous waste liquid has a sealed structure and a structure that can withstand pressure reduction, and a heater 2 is incorporated as a heating means for the aqueous waste liquid. As the heater, an electric type, a steam type, a hot water type, a heating oil type, or the like can be used. An aqueous waste liquid W0 can be stored in the concentration chamber 1, and a drain valve 3 for taking out the concentrated waste liquid W1 is provided in the lower part of the concentration chamber 1. Further, there is an aqueous waste liquid supply pipe 4 for supplying the aqueous waste liquid W0, and a waste liquid supply valve 5 is installed in this. Further, a decompression release valve 6 for releasing the decompression state of the concentration chamber 1 is connected to the upper surface of the concentration chamber 1.

  The concentration chamber 1 is provided with a liquid amount sensor 7 for controlling the amount of the aqueous waste liquid W0. This is a four-point control, which is used for upper limit abnormality, water supply stop, water supply start, and heater protection from the top. As long as they can detect the liquid level, the detection method and the structure are not limited, and a liquid type sensor such as a float type, an electrode type, an ultrasonic type, and an optical type can also be used.

  A coiled cooling tube 9 is incorporated in the cooling chamber 8. The material is preferably a metal with high corrosion resistance and high thermal conductivity, and a copper pipe is suitable, but a stainless steel pipe can also be selected from the viewpoint of corrosion resistance. The cooling pipe 9 passes cooling water WCL from the cooling pipe inlet 9IN and discharges it from the cooling pipe outlet 9OUT. A mist separator 10 for preventing the droplets of the concentrated aqueous waste liquid WO from being mixed into the cooling chamber 8 is provided at a portion connected from the concentration chamber 1 to the cooling chamber 8. The mist separator 10 is preferably a heat-resistant / chemical-resistant resin nonwoven fabric or a metal mesh filter.

A suction pipe 21 is connected to the suction port of the ejector 11 from the lower part of the cooling chamber 8. The suction pipe 21 sucks the gas in the cooling chamber 8 and the concentration chamber 1 to bring the inside into a reduced pressure state. Further, the water vapor is condensed in the cooling chamber 8 to become condensed water WCN, and is sucked into the ejector 11 together with the gas (air, water vapor, etc.) in the cooling chamber 8. Circulating water 14 in the circulation tank 12 is supplied to the ejector 11 using the circulation pump 13 and returns to the circulation tank 12, thereby causing the ejector 11 to be decompressed. In addition, it is preferable to install a liquid amount sensor 15 in the circulation tank 12 for preventing the circulation pump 13 from running idle.
The circulation tank 12 is provided with a circulating water overflow port 16 at the same height as the liquid level, and overflows the circulating water 14 to form distilled waste water W2.
Further, the circulating water 14 in the circulation tank 12 is sent to an oil / water separation unit 18 by using an oil / water separation pump 17 provided separately, where the oil / water separation is performed, and the circulating water 14 from which oil has been removed is returned to the circulation tank 12. At this time, the circulating water 14 separated from the oil and water is returned to the circulating tank 12 from a position above the liquid level of the circulating tank 12, and a partition plate 19 is provided in the circulating tank 12 50 to 100 mm below the liquid level. It is preferable. The partition plate 19 does not completely separate the circulation tank 12 but is provided with a water passage 20 in a part so that water flows from top to bottom. Further, the return water from the ejector 11 is returned below the partition plate 19. By doing so, even if the circulating water 14 returned from the ejector 11 contains oil, it does not overflow directly, but is always discharged as an overflow after passing through the oil-water separation unit 18.

  The oil / water separation unit includes an oil / water separation tank 100 and an oil / water separation filter 101. As the oil / water separation filter 101, a coalescer 101a made of a filter manufactured using lipophilic fibers as a raw material can be used. (In FIG. 1, the oil-water separation filter 101 and the coalescer 101a are the same.) Although not shown in FIG. 1, an ultrafiltration membrane 101b having a molecular weight cutoff of 5,000 to 300,000 is used as an oil-water separation filter. These two filters can also be used in combination.

  In FIG. 1, the example using the coalescer 101a as the oil-water separation filter 101 is shown. The circulating water 14 sucked by the oil / water separation pump 17 from the circulation tank 12 is supplied to the inside of the coalescer 101 a installed in the oil / water separation tank 100. Since a highly lipophilic material is selected for the filter fiber of the coalescer 101a, the fine oil contained in the circulating water 14 is adsorbed on the fiber of the coalescer 101a, and the circulating water 14 from which the oil has been removed is the coalescer. It flows out to the oil-water separation tank 100 from the side surface of 101a. The circulating water 14 in the oil / water separation tank 100 is provided with an overflow pipe 102 so as to overflow from the lower side of the oil / water separation tank 100 through the water passage 105 and flow out to the circulating water tank 12. The oil adsorbed on the coalescer 101a gradually accumulates inside the coalescer 101a, and when it exceeds the accumulation limit, it becomes oil droplets and becomes floating oil OS on the liquid surface of the oil-water separation tank 100. This is discharged out of the oil / water separation tank 100 from the floating oil recovery port 103 installed at the level of the liquid level of the oil / water separation tank 100.

  FIG. 2 shows an example in which a coalescer 101 a and an ultrafiltration membrane 101 b are used as the oil / water separation unit 18. A part of the circulating water 14 in the oil / water separation tank 100 is supplied to the ultrafiltration membrane 101b by using a pressure pump 104. In the ultrafiltration membrane 101b, the oil contained in the circulating water 14 is separated and concentrated according to the molecular weight cut off of the membrane, the circulating water 14a from which the oil has been removed is returned to the circulation tank 12, and the circulating water 14b that has concentrated the oil is separated from the oil / water. It connects with the suction piping 22 of the pump 17, and performs oil-water separation in the coalescer 101a again. The molecular weight cut off of the ultrafiltration membrane 101b can be 5,000 to 300,000, preferably 50,000 to 100,000.

  Example 1 is shown based on the basic form shown in FIG. The first embodiment corresponds to claim 1.

The aqueous waste liquid to be concentrated was an alkaline cleaning liquid containing about 0.1% of machining oil, and the machining oil was emulsified and in a cloudy state.
The concentrating chamber 1 has a cylindrical shape made of stainless steel, has a capacity capable of storing 20 L of aqueous waste liquid, an electric heater is used as the heater 2, and a heat output is 10 kW.
A tap water having a water temperature of 15 ° C. was passed through the cooling pipe 9 as cooling water WCL at a rate of 5 L / min.
By circulating the circulating water 14 through the ejector 11, the internal pressure of the concentrating chamber 1 and the cooling chamber 8 is reduced from atmospheric pressure (101 kPa) to 10 to 15 kPa. As a result, the aqueous waste liquid WO is evaporated at a liquid temperature of 35 to 55 ° C. It boiled. Moreover, the oil-water separation pump 17 was started and the oil content of the circulating water 14 was removed. TKC100-25 manufactured by Takahashi Metal Co., Ltd. was used as the coalescer 101a as the oil / water separation filter.

  The evaporated water vapor is cooled in the cooling chamber 8, becomes condensed water WCN, is sucked into the ejector 11, merges with the circulating water 14, and flows into the circulation tank 12. The flow rate of the distilled waste water W2 overflowed at this time was 13 to 16 L / hour. This is equal to the amount of condensed water WCN and equal to the amount of evaporated water wastewater WO. The outlet temperature of the cooling water WCL was 41 ° C.

  Concentration treatment is continued in this state, and when the amount of the aqueous waste liquid WO in the concentration chamber 1 decreases to about 10 L, the waste liquid supply valve 5 is opened to suck the aqueous waste liquid from the outside, and the aqueous waste liquid WO liquid in the concentration chamber 1 is sucked. When the amount reached 20 L, the waste liquid supply valve 5 was closed, and the concentration process was resumed and continued. By repeating this, 400 L of aqueous waste liquid could be converted to 20 L of concentrated waste liquid. The concentration factor is 20 times.

As Example 2, the example which used the ultrafiltration membrane for the oil-water separation filter of Example 1 is shown. (See FIG. 2) A regenerated cellulose spiral membrane was used for the ultrafiltration membrane 101b. A membrane with a molecular weight cut-off of 100,000 was used. The second embodiment corresponds to the second aspect.
Other conditions are the same as those in the first embodiment.

Comparative Example 1

As Comparative Example 1, the oil / water separation pump 17 was stopped and the concentration treatment was performed. Other processing conditions are the same as those in the first embodiment.
Table 1 shows the processing conditions of Example 1, Example 2, and Comparative Example 1 and the water quality of the distilled waste water W2.

  The distilled waste water of Example 1 was lower than Comparative Example 1 in both turbidity and n-hexane extract, and the water quality of the distilled waste water was improved. In Example 2, the turbidity and n-hexane extract were lower than in Example 1.

Example 3 will be described with reference to FIG. Example 3 corresponds to claim 3 and is an example in which the cooling water tank 200 is used to recover the thermal energy used for heating the concentrated liquid in the evaporating and concentrating device, thereby improving the energy efficiency.
In FIG. 3, the concentrating part, the cooling part, the circulating water part, and the oil / water separation unit part of the evaporative concentration apparatus are the same as those in FIG. 1 or FIG. In FIG. 3, these parts are expressed as an evaporation concentrator main body VE.

The cooling water tank 200 stores the cooling water WCL that circulates in the cooling pipe 9 of the evaporative concentration apparatus main body VE. A suction port 201 is provided at the lower part of the cooling water tank 200, and the cooling water WCL is supplied from here to the cooling pipe inlet 9IN of the evaporative concentrator body VE using the cooling water pump 202. The cooling water WCL that has passed through the cooling pipe 9 is heated and returns to the cooling water tank 200 from the cooling pipe outlet 9OUT through the return port 203 in the cooling water tank 200. Moreover, the heated cooling water WCL can be taken out from the water intake port 204 provided in the cooling water tank 200, and can be used for other purposes as hot water. In order to supplement the extracted cooling water WCL, the cooling water WCL is replenished from a replenishing port 205 provided in a relatively lower part of the cooling water tank 200.
At this time, the suction port 201 and the supply port 205 are arranged below the return port 203 and the outlet 204.
The cooling water tank 200 is provided with a liquid amount sensor 206 for controlling the cooling water amount. This is a two-point control, where the top is for supply stop and the bottom is for start supply.
Preferably, a partition plate 207 is provided between the return port position, the take-out port position and the suction port position, and the replenishment port position so that the water above and below the cooling water tank 200 is less likely to be mixed. The partition plate 207 does not completely separate the cooling water tank 200 but is provided with a water passage 208 in a part so that water flows from top to bottom.

  In Example 3, the capacity of the cooling water tank 200 was 100 L, the amount of water taken out from the water intake 204 was 4 L / min, and the amount of water to be replenished was 4 L / min. The temperature of the water to be replenished was 15 ° C. The other conditions were the same as in Example 1 and the concentration treatment was performed. As a result, after 3 hours from the start of operation, the temperature of the cooling water WCL at the cooling pipe inlet 9IN was 23 ° C., and the temperature at the cooling pipe outlet 9OUT was 48. ° C. The flow rate of the distilled effluent was 12-14 L / hour. The temperature of the water taken out from the water intake 204 of the cooling water tank 200 was 43 ° C. Table 2 shows the treatment conditions of Example 3 and the water quality of the distilled effluent.

  From this result, the amount of heat recovered as the temperature rise of the cooling water was calculated to be 7.8 kW, and 78% of the capacity of 10 kW of the electric heater used for heating the waste liquid could be recovered.

  Next, as Example 4, an example in which tap water, soft water, or electrolytic alkaline water is used as cooling water will be described. The fourth embodiment corresponds to the fourth aspect.

  Of the used cooling water WCL, tap water from Biwa-cho, Higashi Asai-gun, Shiga Prefecture was used as tap water. The total hardness of tap water was 50 mg / L. As the soft water, tap water was passed through a fully automatic water softener MS-5 manufactured by Miura Kogyo Co., Ltd. to make the total hardness 1 mg / L or less. Moreover, electrolytic alkaline water was electrolyzed using tap water or soft water as raw water using an electrolytic ionic water generator TIWS-IW06 manufactured by Takahashi Metals Co., Ltd. to obtain alkaline water having a pH of 10.4. In addition, the structure of the piping connection between the cooling water tank 200 and the evaporation concentrator main body VE is the same as that of the third embodiment.

  When using the copper pipe as the material of the cooling pipe 9 of the evaporative concentrator and the pipe using the steel pipe, the cooling water inside the cooling pipe when the cooling water WCL is used for 3 months is manufactured. The scale adhesion state and the rust generation state were compared. The results are shown in Table 3.

When tap water is used as cooling water, since a hardness component is included, a scale mainly composed of calcium adheres to the inner surface of the cooling pipe 9 and heat exchange efficiency is lowered. Moreover, generation | occurrence | production of rust was also seen.
When soft water was used as cooling water, scale adhesion did not occur and a decrease in thermal efficiency could be prevented. However, the occurrence of rust is almost the same as in the case of tap water.
When electrolytic alkaline water produced by using tap water as raw water was used as cooling water, the generation of rust on the inner surface of the cooling pipe 9 could be suppressed. This is probably because the pH is alkaline and the anion concentration as typified by chloride ions is low. However, scale adhesion could not be prevented.
In addition, when electrolytic alkaline water generated using soft water as raw water is used as cooling water, in addition to preventing the scale inner surface from adhering to the inner surface of the cooling pipe 9, the generation of rust on the inner surface of the cooling pipe is also suppressed. I was able to.

  As Example 5, an example in which an evaporation concentrating device and an aqueous cleaning device are used in combination will be described. The fifth embodiment corresponds to claims 5 and 6.

FIG. 4 is a flowchart of the system constituting the fifth embodiment.
In this embodiment, a conveyor type two tank cleaning apparatus is shown as an aqueous cleaning apparatus, but the number of cleaning tanks and the cleaning method are not limited to this example, and an aqueous cleaning such as an immersion cleaning method or an ultrasonic cleaning method is used. Any device can be used.
The water-based cleaning apparatus 300 includes a first cleaning tank 301 and a second cleaning tank 302. The cleaning water is showered by cleaning pumps 303 and 304 and shower nozzles 305 and 306 in the cleaning chamber, respectively. The object to be cleaned A is introduced from the entrance 308 of the conveyor 307, and the object to be cleaned is taken out from the exit 309 of the conveyor. When the amount of liquid in the second cleaning tank 302 of the water-based cleaning apparatus decreases to the water supply start level, cleaning water is supplied to the second cleaning tank 302 from the water intake 204 of the cooling water tank 200 of the evaporative concentration apparatus. As a water supply method, the flush water supply valve 310 may be opened to supply water with a difference in liquid level, or a pump (not shown) may be installed and water may be supplied using this. When the amount of liquid in the second cleaning tank 302 reaches the water supply stop level, the water supply is stopped.

When the amount of liquid in the first cleaning tank 301 of the water-based cleaning device decreases to the water supply start level, the cleaning water feed pump 311 of the water-based cleaning device is activated to supply the cleaning water in the second cleaning tank 302 to the first cleaning tank 301. Supply water. The washing water in the first water supply tank 301 is sucked as the aqueous waste liquid WO to be processed by the evaporating and concentrating device and concentrated.
As the cooling water WCL of the evaporative concentrator, electrolytic alkaline water generated by electrolyzing raw water (tap water in Biwa-cho, Higashi-Asai-gun, Shiga-ken) with an electrolytic ion water generator ION made by Takahashi Metal is used. The connection between the cooling water tank 200 and the vacuum volume reducing device VE is the same as in the third and fourth embodiments.

  FIG. 5 is a flow diagram of an aqueous cleaning apparatus when a vacuum volume reducing apparatus is not used as a comparative example. When the amount of liquid in the second cleaning tank 302 of the water-based cleaning device 300 decreases to the water supply start level, electrolytic alkaline water is supplied from the electrolytic ionic water generating device ION, and when the amount of liquid in the second cleaning tank 302 reaches the water supply stop level. Stop water supply.

  Although not shown in FIGS. 4 and 5, each cleaning tank of the water-based cleaning apparatus is provided with a liquid amount sensor that operates at a water supply start level and a water supply stop level. As the liquid amount sensor, a float switch was used in Example 4, but the detection method and structure are not limited as long as the liquid surface height can be detected. Electrode type, ultrasonic type, optical type, etc. It is also possible to use a quantity sensor. An electric heater is installed to heat the cleaning liquid to a temperature of about 60 ° C. The heating means is not limited to an electric heater, and a steam type or the like can also be used.

The specifications and test conditions of the water-based cleaning equipment are as follows.
Capacity of each washing tank: 200L. Electric heater capacity: 10 kW. Shower pressure: 0.3 MPa. Shower flow rate: 100 L / min. Washing liquid temperature: 60 ° C. Conveyor speed: 2 m / min. Cleaning sample: Stainless steel plate (SUS304 size 200 mm × 200 mm × t1.5 mm). Oil applied to the sample: Press working oil (Japanese working oil PG-3066). Oil application amount: 0.8 g / sheet. Washing speed: 8 sheets / min.
Table 4 shows the results of the test conducted for 8 hours under the above conditions.

  In Example 5, 84.7% of the electric heater heat quantity used in the evaporative concentrator could be recovered, thereby reducing the heater power used in the aqueous cleaning device by 8.3 kW. Further, the cleaning liquid in the first cleaning tank 301 of the water-based cleaning apparatus 300 can be continuously concentrated by the evaporative concentration apparatus, whereby the oil concentration in the cleaning liquid in the first cleaning tank 301 and the second cleaning tank 302 is reduced. Example 5 was reduced to 1/2 to 1/5 that of Comparative Example 2. Along with this, the oil removal rate of the washed sample is also improved.

  It is a flowchart of the evaporation concentration apparatus of the water-system waste liquid which uses a coalescer for oil-water separation among the best forms in this invention.   It is a flow figure of the evaporation concentration apparatus of the water-system waste liquid which uses the ultrafiltration membrane for oil-water separation among the best forms in this invention.   It is a flowchart of the Example which combined the cooling water tank with the evaporation concentration apparatus of the aqueous waste liquid in this invention.   It is a flowchart of the Example which combined the evaporation concentration apparatus of the aqueous waste liquid in this invention, the cooling water tank, and the aqueous cleaning apparatus.   It is a flowchart of the conventional water-system washing | cleaning apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Concentration chamber 2 Heater 4 Water-system waste liquid supply pipe 7 Liquid quantity sensor 8 Cooling chamber 9 Cooling pipe 11 Ejector 12 Circulation tank 17 Oil-water separation pump 18 Oil-water separation unit 100 Oil-water separation tank 101 Oil-water separation filter 101a Corelesser 101b Ultrafiltration membrane 200 Cooling water tank 202 Cooling water pump 300 Water-based cleaning device W0 Water-based waste liquid W1 Concentrated waste liquid W2 Distilled waste water WCL Cooling water WCN Condensed water VE Evaporative concentrator main body A To-be-cleaned ION Electrolyzed ion water generator

Claims (6)

In an aqueous waste liquid evaporating and concentrating apparatus, a heater as a heating means for aqueous waste liquid, a concentrating chamber for evaporating and concentrating the aqueous waste liquid by incorporating this heater, and cooling water for cooling and liquefying the steam generated in the concentrating chamber. A cooling pipe for passing water, a cooling chamber for storing the cooling pipe, an ejector for depressurizing the concentration chamber and the cooling chamber, a circulation pump for feeding circulating water to be passed through the ejector, and a circulation for storing the circulating water An apparatus for evaporating and concentrating an aqueous waste liquid comprising a tank and an oil / water separation unit for separating, removing and adsorbing oil contained in circulating water. The oil / water separation unit uses a coalescer made of a filter manufactured using lipophilic fibers as a raw material, and / or an ultrafiltration membrane having a molecular weight cut-off of 5,000 to 300,000. The water-based waste liquid evaporation concentrator according to 1. A cooling water tank for storing cooling water, a cooling water pump for sending cooling water to the cooling pipe, a cooling water return pipe for returning the heated cooling water to the cooling water tank, and a cooling water tank It has a suction port for sucking cooling water for feeding water to the pipe, a return port for returning heated cooling water to the cooling water tank, a replenishment port for replenishing cooling water, and an outlet for taking out cooling water. The outlet position and the supply port position are disposed below the return port position and the outlet position, and the cooling water in the cooling water tank can be taken out from the outlet, and the cooling water can be used as a hot water supply source. The apparatus for evaporating and concentrating an aqueous waste liquid according to claim 1 or 2. The aqueous waste liquid according to any one of claims 1 to 3, wherein the cooling water is soft water having a total hardness of 10 mg / L or less (equivalent to calcium carbonate) or / and electrolytic alkaline water having a pH of 8.0 to 12.0. Evaporative concentration device. In the water-based cleaning device, the cleaning water before being used for cleaning is used as cooling water for the water-based waste liquid evaporation concentrating device according to claims 1 to 4, and the cooling water heated by the evaporation-concentrating device is used for the water-based cleaning device. An aqueous cleaning apparatus characterized by being used as cleaning water. 6. The aqueous cleaning apparatus according to claim 5, wherein the cleaning apparatus is replenished with an amount of new cleaning liquid that compensates for the cleaning liquid reduced by the concentration process while the cleaning liquid of the aqueous cleaning apparatus is concentrated by the evaporative concentration apparatus.

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