JP2004337791A - Oil/water separation method and oil/water separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To separate water from a mixed-solution of water and oil, regardless of the specific gravity of oil. <P>SOLUTION: The oil-water separator 1 comprises: an inclined-panel shaped separation unit 12 having slots S formed on an ultra-hydrophilic slope 7; an oil-recovery tank 4 disposed under the separation unit 12; a water recovery tank 5 also disposed under the separation unit 12. A mixed-solution M of water W and oil O is caused to flow down the slope 7 of the separation unit 12, while the water wetting and spreading over the slope 7 is allowed to drip down from the slots S toward the water-recovery tank 5, and the residual liquid from which the water is separated is recovered into the oil-recovery tank 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an oil-water separator for separating water and oil in a mixture of water and oil.
[0002]
[Prior art]
As a conventional oil-water separator, the one described in Patent Document 1 is exemplified. This device 200 separates the oil water of the collected spilled oil, and as shown in FIG. 14, an inclined plate 201 for flowing the collected spilled oil from the upper end side, and a plurality of inclined plates 201 formed on the inclined plate 201. , An oil / water separation hole 202, a separated oil recovery tank 203 installed at the lower end of the inclined plate 201, and a separated water recovery tank 204 installed below the inclined plate 201.
[0003]
According to this device 200, in order to separate the water mixed in the oil when collecting the spilled oil from the oil, the difference in the specific gravity of the oil and the water is used to cause the spilled oil to flow down on the inclined plate 201, The water flowing in the lower layer is dropped from the oil / water separation hole 202 of the inclined plate, and the oil flowing in the upper layer is caused to flow down on the inclined plate 201.
[0004]
[Patent Document 1]
JP-A-2002-370005
[Problems to be solved by the invention]
However, the conventional apparatus 200 is based on the premise that the specific gravity of oil is lower than that of water, that is, water flows to the lower layer and oil flows to the upper layer, so that the oil has the same or higher specific gravity as water. When a component is contained, there is a problem that the component flows in the lower layer together with water and drops from the oil / water separation hole 202 to the separated water recovery tank 204.
[0006]
An object of the present invention is to solve the above problems and provide an oil / water separation method and apparatus capable of separating water from a mixed liquid of water and oil regardless of the specific gravity of the oil.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the oil-water separation method of the present invention is an oil-water separation method using an inclined plate-shaped separation portion in which a gap, a hole, or a notch is formed on a slope having superhydrophilicity, The mixed liquid of water and oil flows down on the slope of the separation part, and the water that spreads on the slope falls down from the gap, hole, or notch to separate from the oil.
[0008]
Further, the oil-water separation device of the present invention, a gap, a hole, or a notch formed in a slope having superhydrophilicity, an inclined plate-shaped separation portion, and an oil recovery tank installed at the lower end side of the separation portion, A water recovery tank installed below the separation unit, and a mixture of water and oil flows down on the slope of the separation unit, and the water that spreads on the slope is spread downward from the gap, hole, or notch. It is configured to drop into the water recovery tank and recover the residual liquid from which the water has been separated into the oil recovery tank.
[0009]
The slope is not particularly limited, and examples of the slope include planes and curved surfaces.
[0010]
The gap, the hole, or the notch is illustrated as an example in which the gap, the hole, or the notch is elongated so as to extend in a direction in which the slope is inclined.
[0011]
The width of the gap, hole, or notch is not particularly limited, but is exemplified to be 0.3 mm or less. When the thickness is 0.3 mm or less, the gap can be filled with water that is wetted and spread on the slope due to superhydrophilicity, and oil can hardly enter the gap. In addition, this width may be appropriately set wider than 0.3 mm according to the viscosity of the oil contained in the mixed liquid.
[0012]
The separating section exemplifies an aspect in which an oil-repellent coating is applied to a part of the slope.
[0013]
The coating may have water repellency in addition to oil repellency.
[0014]
The slope is exemplified by an embodiment in which a photocatalyst that exhibits superhydrophilicity by light irradiation is coated.
[0015]
Although it does not specifically limit as said photocatalyst, Anatase type titanium oxide which exhibits superhydrophilicity by ultraviolet irradiation is illustrated.
[0016]
In the oil-water separator, an embodiment is provided in which a light source for irradiating the slope with light is exemplified.
[0017]
The slope has an example in which a cross section is formed in a substantially concave arc shape.
[0018]
In the oil-water separator, an embodiment is provided in which means is provided for supplying water to the superhydrophilic slope.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 10 show a first embodiment of the present invention. Hereinafter, an embodiment in which the present invention is embodied in an oil-water separation device will be described with reference to the drawings, together with a separation method performed using the device.
[0020]
The oil-water separator 1 of this embodiment is for separating a mixed liquid M of oil O and water W into oil O and water W, and includes a separation unit 3 supported by a leg frame 2 and a separation unit 3. An oil recovery tank 4 and a water recovery tank 5 for recovering the oil O and the water W separated from each other are provided.
[0021]
The separation unit 3 has a gap S formed on a slope 7 having superhydrophilicity, and an inclined plate-shaped separation part 12 for separating water from the mixed liquid M, and an oil O and an oil O on the slope upper end side of the separation part 12. An input section 11 for inputting a mixed liquid M of water W, and a discharge section 13 for discharging the residual liquid from which water has been separated to the oil recovery tank 4 at the lower end of the slope of the separation section 12 are provided. .
[0022]
The input unit 11 and the discharge unit 13 are coated with a fluororesin (for example, polytetrafluoroethylene) coating as a coating having oil repellency and water repellency on the entire surface so that oil O and water W do not adhere. It has become.
[0023]
The separation unit 12 has a large number of separation pieces 21 provided between side frames 20 that integrally connect both sides of the input unit 11 and the discharge unit 13 to each other. The separation pieces 21 are formed in the shape of a prism extending in the direction of inclination of the slope 7, and are arranged in a row in the width direction of the slope 7 in a substantially arc-shaped cross section. The surface of the separation piece 21 is coated with a photocatalyst 25 (for example, anatase-type titanium oxide) that exhibits superhydrophilicity by ultraviolet irradiation. In this example, the upper and lower surfaces and both side surfaces of the separation piece 21 are coated, but the coating on the lower surface can be omitted, and the coating on both side surfaces can be omitted. The separation piece 21 is provided with through holes 21a penetrating the left and right side surfaces at a plurality of locations (three locations in this example) in the length direction. An elongated gap S extending in the direction of inclination of the slope 7 is formed between the separation pieces 21 by interposing the annular spacer 22 therebetween. The separation pieces 21 are connected to each other by a connection bar 23 inserted through the through hole 21 a and the annular spacer 22. A male screw portion 23a is provided on one end side of the connection bar 23, and is attached to the side frame 20 by a nut 24 as a fastening means. In the present embodiment, a spacer having a spring property in the thickness direction (for example, a configuration similar to a spring washer or a rubber washer) is employed as the spacer 22. Are deformed, and the width of the gap S changes.
[0024]
Water discharge ports 15 and 26 for supplying water W to the surface of the separation piece 21 are provided at the upper end side of the slope and the middle of the slope of the separation unit 12, respectively. A guide path 27 for smoothly sending the water W toward the surface of the separation piece 21 is provided in the discharge direction of the water discharge port 26 in the middle of the slope.
[0025]
Describing the operation of the separation unit 12, when the surface of the separation piece 21 is irradiated with ultraviolet rays, the photocatalyst 25 works to make the surface super-hydrophilic. As a result, as shown in FIG. 4, the water W uniformly wets and spreads to cover the surface without gaps, and the oil O floats from the surface. Therefore, by appropriately setting the width of the gap S, only the water W can enter the gap S, so that the water W can be taken out to the lower water recovery tank 5. In this example, since the photocatalyst 25 is also coated on the side surface of the separation piece 21, the surface in the gap S becomes superhydrophilic due to the ultraviolet rays entering the gap S. As a result, the water W also spreads on the surface in the gap S, so that the gap S is filled with the water W and the oil O cannot enter.
[0026]
For example, the separation unit 12 can be appropriately changed as follows.
(A) As shown by a two-dot chain line in FIGS. 1 to 3, a light source 28 for irradiating the slope 7 with ultraviolet rays and a cover 29 for preventing the ultraviolet rays from leaking outside are provided. As shown in FIG. 3, each light source 28 is preferably arranged at the center of the arc of the cross section of the slope 7, so that the slope 7 can be evenly irradiated with ultraviolet rays. Further, it is preferable that the light sources 28 are provided at a plurality of positions (two positions in FIGS. 1 to 3) in the length direction according to the length of the slope 7.
[0027]
(B) A fluororesin (for example, polytetrafluoroethylene) coating 31 is partially applied to the surface of the separation piece 21 as a coating having oil repellency and water repellency. In this case, while the water W is adapted to the superhydrophilic surface, the fluororesin coating 31 acts to float the oil O due to oil repellency. For example, when formed at the edge of the gap S as shown in FIG. 5A, the oil O can be raised near the gap S to make it difficult to enter the gap S. However, the fluororesin coating 31 also has water repellency, and if the entire edge of the gap S is coated with the coating 31, it becomes difficult for the water W to enter the gap S, so that as shown in FIG. Is preferably applied intermittently to the edge of the substrate. Further, the shape of the coating 31 is not particularly limited, but may be V-shaped (see FIG. 2B), linear (see FIG. 2C), or dot-shaped (see FIG. 2D). An example is shown.
[0028]
(C) Instead of coating the photocatalyst 25 on the surface of the separation piece 21, a film 33 carrying the photocatalyst is attached. According to this embodiment, the same effect as that of the separation piece 21 coated with the photocatalyst can be obtained. 6A shows a mode in which the spacing between the separation pieces 21 is secured by the spacers 22 as in the mode of FIG. 3, and FIG. 6B shows the same spacing on the side face of the separation piece 21 in place of the spacer 22. The aspect secured by the provided convex portion 21b is shown.
[0029]
(D) As shown in FIG. 7, a plate 37 having an elongated hole 35 or a notch 36 formed in the inclined direction of the slope 7 is used instead of the separation piece 21.
[0030]
(E) As shown in FIG. 8, the separation section 12 is configured so that the width of the gap S increases in a tapered shape as it goes downward. This makes it easier for the water W to pass through the gap S. Further, according to this configuration, clogging of the gap S due to impurities or lump of oil contained in the mixed liquid M can be suppressed.
[0031]
As shown in FIG. 9, the oil recovery tank 4 includes a stand 40 and an oil recovery bag 41 supported by the stand 40 so as to be exchangeable. The stand 40 includes a pair of support frames 40b erected on a disk-shaped base portion 40a so as to face each other. The oil recovery bag 41 has a sealing opening 42 at the opening edge of the bag body 41a, and a pair of handles 43 and a pair of supported pockets 44 on the outer surface of the bag body 41a. The sealing opening 42 of the present example is sealed by a mouth string 42a, but other sealing means such as a fastener may be appropriately employed. The oil recovery bag 41 is supported by the stand 40 in an open state by mounting the two supported pockets 44 opened downward so as to cover the respective support frames 40b (FIG. 1). (See dash-double-dot line). At this time, the sealing opening 42 is shrunk so as not to block the opening of the bag. The oil recovery bag 41 is not particularly limited, and examples thereof include those made of resin such as polypropylene and polyethylene, and those using a sheet obtained by laminating a flat yarn woven fabric. When the oil recovery bag 41 is made by sewing the sheet, if an oil adsorbent (not shown) is provided on the inner surface of the bag, leakage of the oil O from the seam can be reduced.
[0032]
The water recovery tank 5 is formed in a receiving box shape, and receives the water W dropped from the gap S of the separation unit 12. An oil adsorption mat 46 is provided to adsorb the oil O leaked and mixed with the water W. The water W accumulated in the water recovery tank 5 is sent to a post-processing step (a filtration step or the like) by a pump (not shown).
[0033]
In addition, as shown in FIG. 10, the oil-water separator 1 adsorbs the mixed liquid M to the oil adsorbent 50 formed in various three-dimensional shapes such as a spherical shape, a columnar shape, and a prismatic shape. The mixed liquid M may be compressed by the compression device 51 provided in the charging section 11 and squeezed out of the mixed liquid M to flow into the separating section 12.
[0034]
Next, a method of using the oil-water separator 1 will be described by taking, as an example, a case of separating water W mixed into the oil O when recovering the oil O that has flowed out onto water in the ocean, river, lake, or the like. The oil-water separator 1 is assumed to be installed on an oil recovery boat. In addition, it is assumed that sunlight is applied to the slope 7 and the surface of the separation piece 21 is superhydrophilic.
[0035]
(1) First, the water W is temporarily discharged from the first and second water discharge ports, and the water W is spread over the entire surface of the separation piece 21.
[0036]
(2) The mixed liquid M of the oil O and the water W collected from the water W is poured into the charging section 11. The mixed liquid M flows down on the slope 7 of the separation unit 12, and the water W in the mixed liquid M wets and spreads on the superhydrophilic slope 7 and falls from the gap S to the water recovery tank 5 below. The remaining liquid from which the water W has been separated is recovered in the oil recovery tank 4 via the separation unit 12 and the discharge unit 13. When the mixed liquid M does not contain sufficient water W to cover the entire surface of the separation piece 21, the water W is discharged from the first and second water discharge ports as appropriate. Replenish.
[0037]
According to the oil / water separation device 1 of the present invention configured as described above, the mixed liquid M can be automatically separated into the oil O and the water W simply by flowing down the mixed liquid M on the slope 7 of the separation unit 12. Since the superhydrophilicity is used for separating the oil O and the water W, the water W can be separated from the mixed liquid M of the water W and the oil O regardless of the specific gravity of the oil O.
[0038]
Further, since the gap S is formed to be elongated so as to extend in the inclination direction of the slope 7, the flow of the mixed liquid M is not disturbed, and the superhydrophilic action of the separation unit 12 can be efficiently exhibited. it can.
[0039]
In addition, since the separating section 12 is provided with the oil-repellent fluororesin coating 31 on a part of the slope 7, the oil O can be lifted off the slope 7, and the separation of oil and water can be promoted.
[0040]
Further, if the light source 28 for irradiating the ultraviolet rays on the slope 7 is provided, ultraviolet rays can be obtained even when the weather is bad or after sunset, as compared with the case where sunlight is used. Irrespective of this, it is possible to cause the separation portion 12 to exhibit the superhydrophilic action stably.
[0041]
In addition, since the slope 7 is formed in a substantially concave arc shape in cross section, the ultraviolet light emitted radially from the light source 28 can be applied to the entire slope 7 substantially uniformly.
[0042]
Further, since a means for replenishing water to the slope 7 having superhydrophilicity is provided, if the water contained in the mixed liquid M is small and the surface of the separation piece 21 is not covered with water W, the water is appropriately discharged. By discharging the water W from the outlets 15 and 26, the water W can be supplied.
[0043]
Next, FIG. 11 shows a second embodiment of the invention. The oil-water separation device 60 of this example is different from the first embodiment mainly in the following points. Therefore, the same parts as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof will not be repeated (the same applies to other embodiments described below).
[0044]
The oil-water separator 60 has a multi-stage (three-stage in this example) configuration in which the separation units 3 of the first embodiment are vertically stacked. In this example, the width of the gap S is set to be relatively wider in the upper separation unit 3 than in the lower separation unit 3, and the lower the separation unit 3, the more the clearance unit S passes through the gap S. By reducing the amount of oil, high-purity water W can be finally recovered in the water recovery tank 5. Accordingly, the width of the gap S of the upper separation unit 3 can be set relatively wide, so that the amount of the mixed liquid that can be processed by the oil / water separator 60 per unit time can be increased, and a large amount of mixing can be performed. The liquid can be processed efficiently.
[0045]
According to the present example, in addition to the same effects as in the first embodiment, the above-described effects unique to the present example can also be obtained.
[0046]
Next, FIG. 12 shows a third embodiment of the invention. The oil-water separator of this example is different from the first embodiment mainly in the following points.
[0047]
In the oil-water separation device of this example, the separation unit is provided with a spherical inclined surface 7 as described below, and specifically, the following embodiment is exemplified.
(1) In the embodiment shown in FIG. 12A, the separation unit 71 includes a hollow hemisphere 72 whose lower side is largely open. The outer spherical surface of the hollow hemisphere 72 is the slope 7 for allowing the mixture M to flow down, and the surface of the outer spherical surface is coated with a photocatalyst. The hollow hemisphere 72 is provided with a gap S extending substantially radially from the vertex side to the lower end side in plan view. A water recovery tank 73 is provided below the opening of the hollow hemisphere 72, and an oil recovery tank 74 is provided around the water recovery tank 73. Further, the separation unit 71 of the present example includes a driving unit (for example, an electric motor or an engine) 75 for rotating the hollow hemisphere 72 continuously or intermittently at a constant speed about an axis passing through the central axis thereof. At the same time, an ultraviolet light source 28 is provided on one side of the hollow hemisphere 72 (in this example, the left side of FIG. 5A), and on the other side of the hollow hemisphere 72 (in this example, the right side of FIG. The mixed liquid M is caused to flow down. With this configuration, the mixed liquid M does not flow to the side to be irradiated with the ultraviolet light, so that the spherical surface can be sufficiently irradiated with the ultraviolet light, and the superhydrophilicity can be efficiently exhibited. Then, since the hollow hemisphere 72 is rotationally driven, the spherical surface having the superhydrophilicity sufficiently exerted by the irradiation of the ultraviolet ray is continuously or intermittently moved to the side where the mixed solution M flows down. For this reason, the spherical surface sufficiently exerts the oil-water separation effect on the mixed liquid M. When the liquid mixture M is caused to flow down to the spherical surface, the water W in the liquid mixture M falls through the gap S and is collected in the water recovery tank 73, and the oil O flows down the spherical surface and is collected in the oil recovery tank 74. It has become. Note that the mixed liquid M may flow down over the entire spherical surface without providing the driving means 75.
[0048]
(2) In the embodiment shown in FIG. 12B, the separation unit 81 includes a hollow hemisphere 82 whose upper side is largely open. The inner spherical surface of the hollow hemisphere 82 serves as a slope 7 for allowing the mixed solution M to flow down, and the surface of the inner spherical surface is coated with a photocatalyst. An oil discharge hole 83 penetrating up and down the wall surface is provided in the center of the inside of the hollow hemisphere 82, and a gap S extending from the upper end side of the hollow hemisphere 82 toward the oil discharge hole 83 in a plan view is formed. Is provided. An oil recovery tank 84 is provided below the oil discharge hole 83, and a water recovery tank 85 is provided below the hollow hemisphere 82 around the oil recovery tank 84. A light source 28 for irradiating the inner spherical surface with ultraviolet light is provided at a substantially central position of the hollow hemisphere 82. Then, when the mixed liquid M is caused to flow down from the upper edge side of the inner spherical surface, the water W in the mixed liquid M falls through the gap S and is collected in the water recovery tank 85, and the oil O flows down the inner spherical surface and is discharged. The oil is collected in the oil collecting tank 84 through the hole 83. In addition, similarly to FIG. 12A, a driving unit (for example, an electric motor or an engine) 75 for rotating the hollow hemisphere 82 continuously or intermittently at a constant speed about an axis passing through the center axis thereof is provided. In addition to the above, the ultraviolet light source 28 may be provided on one side of the inner spherical surface of the hollow hemisphere 82, and the mixture M may flow down on the other side of the inner spherical surface of the hollow hemisphere 82.
[0049]
(3) In the mode shown in FIG. 12C, the separation unit 91 has a multistage (three in this example) configuration in which the separation units 71 of FIG. According to this configuration, in addition to the effect similar to that of FIG.
[0050]
According to the present example, in addition to the same effects as in the first embodiment, the above-described effects unique to the present example can also be obtained.
[0051]
Next, FIG. 13 shows a fourth embodiment of the present invention. The oil-water separation device of this example is different from the third embodiment mainly in the following points.
[0052]
In the oil-water separation device of this example, the separation unit is provided with a conical slope 7 as follows, and the following embodiment is specifically exemplified.
(1) In the embodiment shown in FIG. 13A, the separation unit 101 includes a hollow conical body 102 whose lower side is enlarged in diameter and opened. The outer conical surface of the hollow conical body 102 is the slope 7 for causing the mixed liquid M to flow down, and the surface of the outer conical surface is coated with a photocatalyst. A guide member 103 for flowing the mixed liquid M toward the upper end of the hollow cone 102 is provided on the upper end side of the hollow cone 102. In other respects, the configuration is the same as that of the third embodiment shown in FIG. Note that the guide member 103 can be provided in the mode of FIG. 12A in the third embodiment.
[0053]
(2) In the embodiment shown in FIG. 13B, the separation unit 111 has a hollow conical body 112 whose upper side is enlarged in diameter and opened. The inner conical surface of the hollow conical body 112 is the inclined surface 7 for causing the mixed liquid M to flow down, and the surface of the inner conical surface is coated with a photocatalyst. A charging section 113 for charging the mixed liquid M is provided around the upper edge of the hollow cone 112. A water guide member 115 is provided around the oil discharge port 114 of the hollow cone 112 to guide the water W dropped through the gap S toward the inside of the water recovery tank 85. Note that the input section 113 can be provided in the mode of FIG. 12B in the third embodiment.
[0054]
(3) As in the embodiment shown in FIG. 12 (c), a multi-stage configuration in which the separation units of FIG. 13 (a) are vertically stacked.
[0055]
According to the present example, in addition to the same effects as the third embodiment, the above-described effects unique to the present example can be obtained.
[0056]
Note that the present invention is not limited to the above-described embodiment, and may be embodied with appropriate modifications without departing from the spirit of the invention, for example, as described below.
(1) In the first or second embodiment, the inclination angle of the slope 7 is adjustable. For example, providing the leg frame 2 with an adjustment mechanism for adjusting the inclination angle of the separation unit 10 can be mentioned.
(2) In the first or second embodiment, the arrangement of the separation pieces 21 is appropriately changed. For example, the separation pieces 21 may be arranged in a substantially linear cross section (substantially one horizontal line).
[0057]
【The invention's effect】
As described in detail above, the oil-water separator according to the present invention has an excellent effect that water can be separated from a mixture of water and oil regardless of the specific gravity of oil.
[Brief description of the drawings]
FIG. 1 is a perspective view of an oil-water separation device according to a first embodiment of the present invention.
FIG. 2 is a side sectional view of the same device.
FIG. 3 is a sectional view taken along line III-III of FIG. 2;
FIGS. 4A and 4B are views showing a separating section of the apparatus, wherein FIG. 4A is an exploded perspective view and FIG. 4B is a sectional view.
FIG. 5 is a perspective view showing a modification of the separation unit.
FIG. 6 is a cross-sectional view showing another modification of the separation unit.
FIG. 7 is a plan view showing still another modification of the separation unit.
FIG. 8 is a cross-sectional view similar to FIG. 4B, showing still another modification of the separation unit.
FIG. 9 is a perspective view showing an oil recovery tank of the same device.
FIG. 10 is a side sectional view showing a modification of the apparatus.
FIG. 11 is a side sectional view of an oil-water separator according to a second embodiment of the present invention.
FIG. 12 is a side sectional view of an oil-water separator according to a third embodiment of the invention.
FIG. 13 is a side sectional view of an oil-water separator according to a fourth embodiment of the present invention.
FIG. 14 is a perspective view showing a conventional oil / water separator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Oil-water separation device 3 Separation unit 4 Oil recovery tank 5 Water recovery tank 7 Slope 12 Separation part 15 Water discharge port 21 Separator piece 26 Water discharge port 28 Light source 31 Fluororesin coating 33 Film carrying photocatalyst 35 Hole 36 Notch 37 Plate Body 60 oil / water separator 71 separation unit 72 hollow hemisphere 73 water recovery tank 74 oil recovery tank 81 separation unit 82 hollow hemisphere 84 oil recovery tank 85 water recovery tank 91 separation unit 101 separation unit 102 hollow cone 111 separation unit 112 hollow Conical body S Gap M Mixed liquid O Oil W Water

Claims (9)

An oil-water separation method using an inclined plate-shaped separation unit in which a gap, a hole, or a notch is formed on a slope having superhydrophilicity,
An oil-water separation method wherein a mixture of water and oil is caused to flow down on a slope of the separation section, and water that spreads on the slope is dropped downward from the gap, hole, or notch to separate oil from water. An inclined plate-shaped separation part in which a gap, a hole, or a notch is formed on a superhydrophilic slope, an oil recovery tank installed at the lower end side of the separation part, and water installed below the separation part With a recovery tank,
A mixed solution of water and oil is caused to flow down on the slope of the separation unit, and water that spreads on the slope is dropped from the gap, hole, or notch to the water recovery tank below, and the residual liquid from which the water is separated. An oil-water separator configured to collect oil in the oil recovery tank. The oil-water separation device according to claim 2, wherein the gap, the hole, or the notch is elongated so as to extend in a direction in which the slope is inclined. The oil-water separator according to claim 3, wherein the gap, hole, or notch is formed to have a width of about 0.3 mm or less. The oil-water separation device according to any one of claims 2 to 4, wherein the separation unit is provided with an oil-repellent coating on a part of the slope. The oil-water separation device according to any one of claims 2 to 5, wherein the slope is coated with a photocatalyst that exhibits superhydrophilicity by light irradiation. The oil-water separation device according to claim 6, further comprising a light source that irradiates the slope with light. The oil-water separation device according to claim 7, wherein the slope has a substantially concave arc-shaped cross section. The oil-water separation device according to any one of claims 2 to 8, further comprising a unit configured to supply water to the superhydrophilic slope.

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