JPH09314127A - Concentration method of water-soluble oil wastewater - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] Concentrating water-soluble oil wastewater to the limit of concentration to ensure volume reduction and preventing bumping in the concentration process. SOLUTION: The oil-containing wastewater 4 is circulated to a condensing can 6 and is heated and distilled by a heated steam 9 in the condensing can 6 to obtain steam 10.
And the in-can liquid 18 are separated from each other, and the emulsion of the in-can liquid 18 is concentrated from an oil-in-water type to a water-in-oil type to concentrate the water-soluble oil drainage to be discharged as a concentrated liquid 17 out of the concentrated can. Therefore, the viscosity of the concentrate is detected by the viscosity detector 15 and the concentrate 17 is discharged at the concentration limit to reduce the volume to the limit without bumping phenomenon in the concentration process. Disposal can be done economically.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a metal cutting oil drainage,
The present invention relates to a concentration method for heat-distilling and concentrating water-soluble oil-containing wastewater such as machine parts cleaning wastewater and metalworking wastewater to reduce the volume of wastewater to be made into rich oil-containing wastewater.

[0002]

2. Description of the Related Art Conventionally, it has been known and widely used to heat waste water to evaporate the water in the waste water to reduce the water content and to perform a concentration treatment. Further, in this concentrating step, it is also conceivable to control the concentrating process by measuring the specific gravity and water content of the concentrated liquid, as long as it is limited to the treatment with a specific oil-containing water.

[0003]

However, since various oil components are mixed in the wastewater, the measurement is complicated and accurate measurement cannot be performed, and there are many errors, so that the concentration is not reached to the concentration limit. Since the concentration work was stopped within the allowable range, the volume reduction was not sufficiently satisfactory, and the post-disposal was very expensive and there were many problems. Moreover, when the water in the can is evaporated and the oil in the can becomes thicker in the concentrated can, the emulsion type changes from a certain point, and the water in the emulsion particles is heated to steam and expands. Then, the film of oil around the emulsion particles was ruptured to cause a bumping phenomenon, the in-can liquid was scattered inside the can, and the oil mist in the can liquid was scattered and mixed on the water vapor side, resulting in water pollution and separation. There was a defect that the water quality of the water was deteriorated. The present invention is intended to eliminate these conventional drawbacks, by concentrating the water-soluble oil wastewater to the limit of the concentration to ensure volume reduction, and also prevent the occurrence of bumping during the concentration process to remove oil-containing wastewater. It is an object of the present invention to provide a concentration method that enables economical treatment.

[0004]

According to the present invention, oil-containing wastewater is circulated through a concentrating can and heated and distilled by heating steam in the concentrating can to separate it into steam and a liquid in the can. In a water-soluble oil drainage concentrating method of concentrating from oil-in-water type to water-in-oil type and discharging it as a concentrate to the outside of the concentrating can, the viscosity of the concentrating liquid is detected by a viscosity detector and concentrated from the concentrating can at the concentration limit The liquid is discharged.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the embodiment of the present invention, oil-containing wastewater is separated into a floating oil and a water-soluble oil wastewater through an oil separator or a coalescer, and the separated floating oil is stored in an oil storage tank, while The oil drainage is sent to a concentration can. A circulating pump is installed in this condensing can to circulate the liquid inside the can through the circulating liquid pipe, and a viscosity detector of the viscometer is installed in the middle of the circulating liquid pipe, and the water-soluble oil wastewater is heated in the condensing can. It is heated and distilled by steam and separated into water vapor and liquid in the can. Then, the water vapor is sucked into the condenser by the vacuum pump, cooled by the cooling water by the condenser, and flows out as condensed water. This condensed water is clear water and contains no oil. On the other hand, the liquid in the can is gradually concentrated as the water vaporizes. When the water content evaporates and the concentration increases and the oil content in the liquid inside the can becomes thicker, the type of emulsion changes from the oil-in-water type to water-in-oil at a certain point, and its viscosity becomes close to that of oil. That is,
From a certain point, the viscosity of the liquid in the can is 0.5 cp to 5 to 10 c
It rises sharply above p. At the same time, the water-in-oil emulsion particles in the concentrating can expand when water in the particles is heated to change to steam and expand, causing the oil film around the particles to burst and cause bumping. As soon as the viscosity of the concentrate reaches 1 to 5 cp with the viscosity detector, the concentrate valve is opened and the concentrate is discharged from the concentration can. As a result, the water-soluble oil wastewater in the concentrating can can be concentrated to the very limit of the concentration. That is, it is possible to concentrate the water-soluble oil wastewater with high efficiency by concentrating up to the concentration limit depending on the viscosity.

[0006]

EXAMPLE An example of the present invention will be described with reference to the example of FIG. 1. The oil-containing wastewater 4 is circulated in a concentrating can 6 and heated and distilled by a heated steam 9 in the concentrating can 6 to produce steam 10 and a liquid 18 in the can. And concentrates the emulsion of the in-can liquid 18 from the oil-in-water type to the water-in-oil type to concentrate the water-soluble oil wastewater to be discharged outside the concentrated can as the concentrated liquid 17. Viscosity of viscosity detector 1
5, the concentration limit is detected and the concentration liquid is changed from the concentration can 6 to the concentration liquid 17
And the oil-containing wastewater 4 is introduced into the condensing can 6.

In this case, the viscosity is detected by the viscosity detector 15 in the circulation channel of the concentrated liquid or in the concentrating can.
cp, preferably 2 to 3 cp is detected, the concentrated liquid discharge valve 16 in the circulating liquid pipe from the condensing can 6 is opened and discharged, and the discharged valve 16 is closed after discharge, and the water-soluble oil drain valve It is preferable to open 19 and supply the water-soluble oil drainage 4 into the concentrating can 6.

Thus, the oil-containing wastewater 1 is separated into the floating oil 3 and the water-soluble oil wastewater 4 through the oil separator 2 or the coiler, and the separated floating oil 3 is stored in the oil storage tank 5, while the water-soluble oil wastewater is discharged. 4 is sent to the concentrated can 6. A circulating pump 7 is installed in the concentrating can 6, and a liquid 18 in the can is circulated by a circulating liquid pipe 8. A viscosity detector 15 of a viscometer is installed in the middle of the circulating liquid pipe 8. Is heated and distilled by the heating steam 9 in the concentrating can 6 to be separated into the steam 10 and the liquid 18 in the can. Then, the water vapor 10 is sucked by the condenser 11 by the vacuum pump 14, cooled by the cooling water 12 by the condenser 11, and flows out as condensed water 13. The condensed water 13 is clear water and contains no oil. On the other hand, the liquid 18 in the can is gradually concentrated as the water vaporizes. Generally, water-soluble oil drainage is an oil-in-water type emulsion,
Its viscosity is almost the same as that of water, ie 50C
When concentrated in, the viscosity of the liquid in the can is initially around 0.5 cp, which is the same as that of water. However, when the water content evaporates and the concentration increases and the oil content in the liquid 18 in the can becomes thick, the emulsion type changes from the oil-in-water type to the water-in oil at a certain point, and the viscosity becomes close to the viscosity of the oil. That is, from a certain point in time, the viscosity of the in-can liquid 18 rapidly increases from 0.5 cp to 5 to 10 cp or more. At the same time, the water-in-oil emulsion grains in the concentrating can 6 are heated by the water in the grains to expand into steam, causing the oil film around the grains to burst and causing bumping. With the viscosity detector 15, the viscosity of the concentrate is 1 to
Immediately after reaching 5 cp, the concentrated liquid discharge valve 16 is opened to discharge the concentrated liquid 17 from the concentrated can 6. As a result, the water-soluble oil wastewater in the concentrating can can be concentrated to the very limit of the concentration. That is, it is possible to concentrate the water-soluble oil wastewater with high efficiency by concentrating up to the concentration limit depending on the viscosity.

As the water-soluble oil drainage 4, the oil-containing drainage 1 is a water-soluble oil drainage 4 in which the floating oil 3 is separated through an oil separator 2 or a coalescer, and the water-soluble oil drainage 4 is concentrated. It is considered that the solution is sent to the can 6 and repeatedly circulated as the internal liquid of the concentrating can 6 in a batch or continuous manner by the circulation pump 7, and when the concentration progresses and the volume is reduced, it is discharged as the concentrated liquid 17 and post-disposal.

As shown in FIG. 1, in heating and condensing water-soluble oil wastewater, a viscosity detector 15 is provided to detect the point where the shape of the emulsion changes from an oil-in-water type to a water-in-oil type according to the concentration of the waste liquid. Then
A concentrator that can concentrate to the limit of concentration is used.
When water-soluble oil wastewater is concentrated as shown in, the viscosity increases sharply from a certain point, and it shows that the water content at which the viscosity sharply increases varies depending on the type of oil wastewater. It is better to consider

In the embodiment shown in FIG. 3, the viscosity detector 15 ₁
Can also be used as a concentrating device which is provided near the bottom of the concentrating can 6 and detects the viscosity of the liquid 18 in the can. When a multi-effect can (double-effect can or triple-effect can), that is, a multi-effect concentrator in which a plurality of the concentrating cans 6 are connected in series, is used as in the example of FIG. If the viscosity detector 15 ₁ of a viscometer is provided in the concentration can to concentrate the water-soluble oil wastewater to the concentration limit, or by installing the viscosity detector 15 ₁ in other evaporators, It is also possible to use a concentrating device that can concentrate the oil wastewater to the concentration limit.

[0012]

INDUSTRIAL APPLICABILITY According to the present invention, oil-containing wastewater is circulated through a concentrating can and heated and distilled in the concentrating can with heated steam to separate into water vapor and a liquid in the can, and an emulsion of the liquid in the can is oil-in-water type. In a water-soluble oil drainage concentrating method in which the concentrate is concentrated to waterine oil and discharged as a concentrate to the outside of the concentrator, the viscosity of the concentrate is detected by a viscosity detector, and the concentrate is discharged from the concentrate can at the concentration limit. As a result, the concentration process is accurately detected and oil mist is prevented from mixing into the water vapor side, while eliminating the conventional drawbacks and concentrating the water-soluble wastewater to the limit of concentration to ensure volume reduction. There is an effect that the occurrence of bumping in the process can be prevented, the economical disposal of the oil-containing wastewater can be efficiently performed, and the treatment work of the water-soluble oil wastewater can be significantly improved.

[Brief description of drawings]

FIG. 1 is a system explanatory view of an embodiment method of the present invention.

FIG. 2 is a characteristic diagram showing the relationship between the viscosity (cp) of the treatment liquid and the water content (% by weight) in the concentration step, where A and B sharply increase in viscosity with different types of water-soluble oil wastewater. It shows that the water content is various.

FIG. 3 is a system diagram of a part of a method according to another embodiment of the present invention.

FIG. 4 is a system diagram of still another embodiment of the present invention.

[Explanation of symbols]

1 ... Oil-containing drainage 2 ... Oil separator 3 ... Floating oil 4 ... Water-soluble oil drainage 5 ... Oil storage tank 6 ... Concentrator 7 ... Circulation pump 8 ... Circulating liquid piping 9 ... Heating steam 10 ... Steam 11 ... Condenser 12 ... Cooling water 13 ... Condensed water 14 ... Vacuum pumps 15 and 15 ₁ ... Viscosity detector 16 ... Concentrated liquid discharge valve 17 ... Concentrated liquid 18 ... Can liquid 19 ... Water-soluble oil drain valve

Claims (3)

[Claims] 1. An oil-containing wastewater is circulated through a concentrating can, and is heated and distilled by heating steam in the concentrating can to separate into water vapor and a liquid in the can, and an emulsion of the liquid in the can is changed from an oil-in-water type to a water-in oil. In a method for concentrating water-soluble oil wastewater, which is concentrated in a mold and discharged as a concentrated liquid to the outside of a concentrated can, the viscosity of the concentrated liquid is detected by a viscosity detector, and the concentrated liquid is discharged from the concentrated can at the concentration limit. A method for concentrating water-soluble oil wastewater. 2. The opening / closing control of the discharge valve in the circulating liquid piping from the concentrating can is detected by detecting that the viscosity detected by the viscosity detector has a viscosity of 1 to 5 cp in the concentrating liquid circulation channel or the concentrating can. The method for concentrating water-soluble oil wastewater according to claim 1. 3. When using a multi-effect concentrator in which a plurality of concentrators are connected in series, a viscometer is provided in the final concentrator to concentrate the water-soluble oil wastewater to the concentration limit.
Alternatively, the water-soluble oil wastewater concentration method described in 2.