Oil-water separation device and oil-water separation method

Abstract

To provide an oil / water separator and an oil / water separation method capable of reducing a device height for reducing a work load when transporting the device and reducing cost of the device itself.SOLUTION: An oil / water separator 1 comprises: a closed vessel 2 partitioned into first and second chambers 20, 21; a first coalescer 3 which is provided so that mixture passes through the first chamber 20, the first coalescer 3 capturing oil droplets in the mixture for making the droplets into coarse grains; a second coalescer 4 which is provided so that the mixture after passing through the first coalescer 3 passes through the second chamber 21, the second coalescer 4 capturing oil droplets in the mixture for making the droplets into coarse grains; a nozzle 5 which is supported by a support plate 25 which partitions the first chamber 20 into an upper space 20A and a lower space 20B, the nozzle 5 formed into an L shape so that an upper end opening 51 introduces the mixture from the upper space 20A and a lower end opening 50 derives the mixture to the lower space 20B, and the lower end opening 50 is directed in a horizontal direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an oil-water separation apparatus and an oil-water separation method for separating oil from a mixture of water and oil, such as wastewater such as building water in ships. [Background technology]

[0002] As a conventional oil-water separation device, Patent Document 1 discloses an upper and lower three-stage oil-water separation device 100 in which a vertical cylindrical sealed container 101 is partitioned into a first chamber 103 equipped with a first coalescer 102, a second chamber 105 equipped with a second coalescer 104 below the first chamber 103, and a third chamber 107 equipped with a third coalescer 106 below the second chamber 105, as shown in Fig. 12. The first coalescer 102, the second coalescer 104, and the third coalescer 106 each include a porous filter, and the lower the coalescer, the finer the filter.

[0003] In the oil-water separator 100 of Patent Document 1, the mixed liquid is supplied to the first chamber 103 in the sealed container 101, and the floating oil is separated first due to the difference in specific gravity. The mixed liquid from which the floating oil has been removed passes through the first coalescer 102, and at this time, large oil droplets that are turbid in the mixed liquid are captured by the first coalescer 102, and the captured oil droplets combine with each other to form coarse particles. As a result, the coarse oil droplets are separated from the mixed liquid by increasing their buoyancy and floating up after being detached from the first coalescer 102. The mixed liquid after passing through the first coalescer 102 passes through the second coalescer 104 provided on the partition plate 108 that separates the first chamber 103 and the second chamber 105 and is supplied to the second chamber 105. At this time, small oil droplets that are turbid in the mixed liquid and are not captured by the first coalescer 102 are captured by the second coalescer 104, and the captured oil droplets combine with each other to form coarse particles. As a result, the coarse oil droplets are separated from the mixed liquid by increasing their buoyancy and rising after being detached from the second coalescer 104. The mixed liquid after passing through the second coalescer 104 passes through the third coalescer 106 provided on the partition plate 109 separating the second chamber 105 and the third chamber 107, and is supplied to the third chamber 107. At this time, smaller oil droplets that are turbid in the mixed liquid and were not captured by the second coalescer 104 are captured by the third coalescer 106, and the captured oil droplets combine with each other to become coarse particles. As a result, the coarse oil droplets are separated from the mixed liquid by increasing their buoyancy and rising after being detached from the third coalescer 106.

[0004] The second chamber 105 is divided into an upper space and a lower space by a partition plate 113, and the mixed liquid after passing through the second coalescer 104 is supplied from the second chamber 105 to the filter 112 through an outlet 110 communicating with the upper space, and after solid matter contained in the mixed liquid is removed in the filter 112, the mixed liquid is returned again to the second chamber 105 through an inlet 111 communicating with the lower space. This prevents the filter mesh of the third coalescer 106, which is the densest, from becoming clogged with solid matter contained in the mixed liquid. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-288435 A Summary of the Invention [Problem to be solved by the invention]

[0006] The oil-water separation device 100 of Patent Document 1 has a three-stage configuration of a first coalescer 102, a second coalescer 104, and a third coalescer 106, so the height of the device is inevitably high, which increases the workload when transporting the device and increases the cost of the device itself. Here, in order to lower the height of the oil-water separation device, it is also possible to simply omit the second chamber (second coalescer) from the oil-water separation device and pass the mixed liquid that has passed through the first coalescer 102 directly through a filter 112 and then through the third coalescer 106, as shown in Figure 13. 13, the oil is captured by the first coalescer 102, coarsens up, and then passes through the first coalescer 102, accumulating below it to form an oil layer, which is then pushed by the water flowing from above, generating oil bubbles (oil on the outside and water on the inside) in the space below the first coalescer 102 in the first chamber 103, filling the space with oil bubbles. When these oil bubbles are supplied to the filter 112 or the third coalescer 106, the filtering resistance of the filter 112 increases significantly due to the oil, hindering the filtering process, or the filter of the third coalescer 106 becomes clogged with oil.

[0007] An object of the present invention is to provide an oil-water separation device and an oil-water separation method that can solve the above problems. [Means for solving the problem]

[0008] The first aspect of the present invention relates to an oil-water separation device that performs a process of floating and separating oil from a mixture of water and oil. The oil-water separation device of the present invention is characterized in that it comprises: an airtight container whose internal space is divided into upper and lower first and second chambers, and into which the mixture is supplied to the first chamber; a first coalescer that is provided so that the mixture passes through the first chamber, and captures oil droplets in the mixture and turns them into coarse particles; a second coalescer that is provided so that the mixture passes through the second chamber after passing through the first coalescer, and captures oil droplets in the mixture and turns them into coarse particles; and a nozzle supported by a support plate that divides the first chamber into an upper space on the first coalescer side and a lower space on the second chamber side, the nozzle having an upper end opening that introduces the mixture from the upper space and a lower end opening that discharges the mixture to the lower space, and the nozzle is L-shaped so that the lower end opening faces horizontally.

[0009] In the oil-water separation device of the present invention, the flow velocity of the mixed liquid discharged from the lower end opening of the nozzle to the lower space is preferably 0.1 m / s or more and 2.0 m / s or less.

[0010] In addition, the oil-water separation device of the present invention can preferably be configured to further include a filter for removing solids in the mixed liquid supplied from the lower space, and the second coalescer can be configured to include a circular cylindrical coarse-grain filter and be arranged sideways in the second chamber so that the axial direction of the coarse-grain filter extends horizontally, and the mixed liquid after passing through the filter is introduced into the hollow interior of the coarse-grain filter.

[0011] In addition, the oil-water separation device of the present invention can preferably be configured so that the flow velocity of the mixed liquid introduced into the hollow interior of the coarse-grain filter is 0.1 m / s or more and 1.0 m / s or less.

[0012] In the oil-water separation apparatus of the present invention, preferably, the second coalescer further includes a dispersion tube inserted into the hollow interior of the coarse-grain filter, and is configured so that the mixed liquid after passing through the filter is introduced into the hollow interior of the dispersion tube, and the dispersion tube can be configured to have a plurality of liquid passage holes formed at intervals along its axial and circumferential directions.

[0013] In addition, the oil-water separation device of the present invention can preferably be configured so that the flow velocity of the mixed liquid discharged from the liquid passage hole of the dispersion pipe into the hollow interior of the coarse-grain filter is 0.4 m / s or more and 1.0 m / s or less.

[0014] In the oil-water separation device of the present invention, the coarse-particle filter can be preferably configured to be made of a hydrophobic material.

[0015] In addition, in the oil-water separation device of the present invention, preferably, the sealed container is provided with an insertion portion that allows the second coalescer to be inserted sideways into the second chamber, and the second coalescer is arranged sideways in the second chamber by an attachment means so that the axial direction of the coarse-grain filter extends horizontally, and the attachment means includes at least two parallel guide rails extending horizontally inward from the insertion portion, and a pressure plate attached to the end of the second coalescer that is inserted first into the insertion portion, and the pressure plate is formed with at least two notches that receive corresponding guide rails to slide the pressure plate on the at least two parallel guide rails and regulate the circumferential rotation of the second coalescer.

[0016] The second aspect of the present invention relates to an oil-water separation method for performing a process for floating and separating oil from a mixture of water and oil. The oil-water separation method of the present invention includes the steps of: supplying a mixture to an upper space of a sealed container in which an internal space is divided into upper and lower first and second chambers and the first chamber is partitioned into an upper space and a lower space by a support plate; passing the mixture through a first coalescer provided in the upper space to capture and coarse oil droplets in the mixture; introducing the mixture in the upper space that has passed through the first coalescer from an upper end opening of an L-shaped nozzle supported by the support plate and leading it to the lower space from a lower end opening facing horizontally in the lower space; and passing the mixture in the lower space through a second coalescer provided in the second chamber to capture and coarse oil droplets in the mixture.

[0017] In the oil-water separation method of the present invention, the flow velocity of the mixed liquid discharged from the lower end opening of the nozzle to the lower space is preferably 0.1 m / s or more and 2.0 m / s or less.

[0018] In addition, in the oil-water separation method of the present invention, preferably, the second coalescer includes a circular cylindrical coarse-grained filter and is arranged sideways in the second chamber so that the axial direction of the coarse-grained filter extends horizontally, and the flow velocity of the mixed liquid when introduced into the hollow interior of the coarse-grained filter is 0.1 m / s or more and 1.0 m / s or less.

[0019] In addition, in the oil-water separation method of the present invention, preferably, the second coalescer includes a circular cylindrical coarse-grained filter and a dispersion tube inserted into the hollow interior of the coarse-grained filter, and is arranged sideways in the second chamber so that the axial direction of the coarse-grained filter extends horizontally, and the dispersion tube has a plurality of liquid passage holes formed therein at intervals along its axial and circumferential directions, and can be configured to introduce the mixed liquid into the hollow interior of the dispersion tube.

[0020] In addition, in the oil-water separation method of the present invention, it is preferable that the flow velocity of the mixed liquid discharged from the liquid passage hole of the dispersion pipe into the hollow interior of the coarse-grained filter is configured to be 0.4 m / s or more and 1.0 m / s or less.

[0021] In the oil-water separation method of the present invention, the coarse-grain filter can preferably be configured to be made of a hydrophobic material. Effect of the Invention

[0022] According to the present invention, the height of the apparatus can be reduced due to the two-stage configuration of the first and second coalescers, which reduces the workload when transporting the apparatus and reduces the cost of the apparatus itself.

[0023] In addition, even if oil bubbles are generated in the mixed liquid after passing through the first coalescer, the oil bubbles are guided from the upper space to the lower space of the first chamber through the nozzle, whereby the oil bubbles become smaller, and the small oil bubbles rise to the top of the lower space after being guided out of the nozzle, so that the lower space is prevented from being filled with oil bubbles, and thus the oil bubbles can be prevented from being supplied to the downstream second coalescer, etc. [Brief description of the drawings]

[0024] [Figure 1] 1 shows a schematic configuration of an oil-water separation device of the present embodiment. [Diagram 2] The external appearance and internal structure of the second coalescer are shown. [Diagram 3] 1 shows the fixing plate as viewed from the front. [Figure 4] 1 shows the pressure plate as seen from the front. [Diagram 5] 1 shows the internal structure of the second coalescer. [Figure 6] 1 shows the insertion part of the sealed container as viewed from the front. [Figure 7] 1 shows the vicinity of the insertion part of the sealed container as viewed from above. [Figure 8]1 shows a state in which a second coalescer is installed in the second chamber of the sealed container. [Figure 9] 1 shows a state in which a second coalescer is installed in the second chamber of the sealed container. [Figure 10] 2 shows the state of a mixed liquid treated by the oil-water separation device of this embodiment. [Figure 11] 13 shows the internal structure of a modified second coalescer. [Figure 12] 1 shows a schematic configuration of a conventional oil-water separation device. [Figure 13] 1 shows a schematic configuration of a modified example of a conventional oil-water separation device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 shows a schematic configuration of an oil-water separation device 1 according to one embodiment of the present invention. The oil-water separation device 1 is used for performing a process of floating and separating oil from a mixture of water and oil, such as wastewater such as building water in a ship.

[0026] As shown in Figure 1, the oil-water separation device 1 comprises a sealed container 2 whose internal space is divided by a partition plate 26 into an upper and lower first chamber 20 and a second chamber 21, a first coalescer 3 provided in the first chamber 20, a second coalescer 4 provided in the second chamber 21, and a nozzle 5 supported by a support plate 25 that divides the first chamber 20 into an upper space 20A on the first coalescer 3 side and a lower space 20B on the second chamber 21 side.

[0027] The sealed container 2 includes a vertically long circular cylindrical peripheral wall portion 22, a bottom portion 23 that closes the lower end opening of the peripheral wall portion 22, and an upper lid portion 24 that closes the upper end opening of the peripheral wall portion 22. The internal space of the sealed container 2 is divided into an upper first chamber 20 and a lower second chamber 21 by horizontally arranging a partition plate 26 so that the mixture cannot flow therethrough. In addition, the first chamber 20 is divided into an upper space 20A and a lower space 20B by horizontally arranging a support plate 25 having a through hole in the center so that the mixture can flow therethrough.

[0028] A circular cylindrical supply unit 10 for supplying the mixed liquid to the upper space 20A of the first chamber 20 is provided on the peripheral wall 22 surrounding the upper space 20A of the first chamber 20 of the sealed container 2. The supply unit 10 is located above the first coalescer 3. A flow path and a pump P are connected to the supply unit 10, and the mixed liquid to be treated is continuously supplied from the supply unit 10 into the sealed container 2 by driving the pump P.

[0029] A cylindrical discharge part 11 is provided at a position above the supply part 10 on the peripheral wall part 22 surrounding the upper space 20A of the first chamber 20 of the sealed container 2 for discharging the oil that has risen to the surface and separated from the mixed liquid from the upper space 20A of the first chamber 20. The discharge part 11 is L-shaped with its upper end opening facing vertically upward and facing the upper lid part 24, and its lower end opening facing horizontally. A flow path and an on-off valve V1 are connected to the discharge part 11, and the oil is discharged from the discharge part 11 to the outside of the sealed container 2 by opening the on-off valve V1.

[0030] An oil level detector 8 for detecting the oil level is provided on the peripheral wall 22 surrounding the upper space 20A of the first chamber 20 of the sealed container 2 at a position above the supply part 10 and at a circumferentially different position from the discharge part 11. When the oil level detector 8 detects that an appropriate amount of oil has accumulated, the on-off valve V1 opens, and is automatically controlled so that the on-off valve V1 is closed in other cases.

[0031] The first coalescer 3 is horizontally installed in the upper space 20A of the first chamber 20 so as to be located between the supply unit 10 and the support plate 25, and the mixed liquid passes through it from above to below. The shape of the first coalescer 3 in a plan view is the same shape and size as the cross section of the sealed container 2.

[0032] The first coalescer 3 includes a porous coarse-grain filter. The coarse-grain filter has a function of capturing oil droplets that become turbid in the mixed liquid while the mixed liquid passes through a plurality of holes, and increasing the oil droplet size by bonding the oil droplets together to coarsen them. The coarse-grained oil droplets have increased buoyancy, so they separate from the mixed liquid by floating up after detaching from the first coalescer 3, and accumulate at the top of the upper space 20A of the first chamber 20 (below the upper lid portion 24).

[0033] The coarse-grain filter of the first coalescer 3 captures relatively large oil droplets that are turbid in the mixed liquid and coarses them. For the coarse-grain filter of the first coalescer 3, for example, a laminate in which a plurality of metal meshes such as sheet-shaped tungsten or stainless steel are laminated one on top of the other can be used. The size of the mesh (opening) of the coarse-grain filter of the first coalescer 3 is not particularly limited. The coarse-grain filter of the first coalescer 3 is not limited to the above-mentioned laminate of metal meshes, and various configurations that have been known in the past can be used.

[0034] The support plate 25, which divides the first chamber 20 into an upper space 20A and a lower space 20B, is horizontally disposed across the first chamber 20 so as to be located below the first coalescer 3. A through hole is formed in the center of the support plate 25, and a nozzle 5 is attached to the lower surface of the support plate 25.

[0035] The nozzle 5 has a circular cylindrical shape having a predetermined inner diameter and an L-shape in a vertical cross section. The nozzle 5 is supported by the support plate 25 so that the upper end opening 51 faces vertically upward and the lower end opening 50 faces horizontally. The upper end opening 51 of the nozzle 5 is located directly below the through hole of the support plate 25 and communicates with the upper space 20A of the first chamber 20. The lower end opening 50 of the nozzle 5 faces the peripheral wall portion 22 of the sealed container 2 in the lower space 20B of the first chamber 20. The nozzle 5 introduces the mixed liquid from the upper space 20A into the inside from the upper end opening 51 and discharges the mixed liquid from the lower end opening 50 to the lower space 20B. The nozzle 5 may be formed by integrally forming a straight pipe portion extending vertically and a bent pipe portion bent into an L shape, or may be formed by connecting an L-shaped elbow to a straight pipe.

[0036] The size of the nozzle 5 is appropriately set according to the size of the device. Although not particularly limited, for example, when the inner diameter of the sealed container 2 in the lower space 20B of the first chamber 20 is about 300 mm to 950 mm and the height is about 150 mm to 400 mm, the inner diameter of the nozzle 5 can be 10 mm to 55 mm, and the length of the nozzle 5 can be 50 mm to 200 mm. The nozzle 5, which will be described in detail later, is for changing oil bubbles generated in the mixed liquid after passing through the first coalescer 3 into small oil bubbles and discharging them into the lower space 20B of the first chamber 20. In order to effectively achieve this purpose, it is preferable to set the inner diameter of the nozzle 5 so that the flow velocity V1 of the mixed liquid drawn out from the lower end opening 50 of the nozzle 5 described later is within a predetermined range.

[0037] A circular cylindrical discharge part 12 for discharging oil that has floated and separated from the mixed liquid from the lower space 20B of the first chamber 20 is provided in the peripheral wall part 22 surrounding the lower space 20B of the first chamber 20 of the sealed container 2, at a position immediately below the support plate 25. A flow path and an on-off valve V2 are connected to the discharge part 12, and the oil is discharged from the discharge part 12 to the outside of the sealed container 2 by opening the on-off valve V2.

[0038] A circular cylindrical discharge part 13 for discharging drainage such as moisture and sludge that have settled in the first chamber 20 from the first chamber 20 is provided at a position immediately above the partition plate 26 on the peripheral wall part 22 surrounding the lower space 20B of the first chamber 20 of the sealed container 2. A flow path and an on-off valve V3 are connected to the discharge part 13, and the drainage is discharged from the discharge part 13 to the outside of the sealed container 2 by opening the on-off valve V3.

[0039] A circular cylindrical outlet part 14 for guiding the mixed liquid from the lower space 20B of the first chamber 20 to the filter 6 is provided in the peripheral wall part 22 surrounding the lower space 20B of the first chamber 20 of the sealed container 2 at a position immediately above the partition plate 26 and at a position different in the circumferential direction from the discharge part 13. A flow path and an on-off valve V4 are connected to the outlet part 14, and the mixed liquid is discharged from the outlet part 14 to the outside of the sealed container 2 by opening the on-off valve V4.

[0040] The mixed liquid discharged from the discharge portion 14 is supplied to the filter 6, and the filter 6 separates and removes solid matter (including suspended solids (SS)) contained in the mixed liquid from the mixed liquid. The filter 6 includes a housing 60 and a filter 61 detachably attached within the housing 60. The filter 61 is not particularly limited as long as it can separate and remove solid matter (including suspended solids (SS)) in the mixed liquid from the mixed liquid, and various types of filters having conventionally known configurations can be used, such as filter paper, sheet filters made of fiber aggregates such as woven fabric, nonwoven fabric, and knitted fabric, bag filters, membrane filters, and cartridge filters such as pleated filters. The fibers constituting the fiber aggregate are not particularly limited, and may be natural fibers, synthetic fibers, glass fibers, or combinations of these.

[0041] The housing 60 is provided with a circular cylindrical inlet 62 through which the mixed liquid before filtration flows into the housing 60, and a circular cylindrical outlet 63 through which the mixed liquid after filtration flows out of the housing 60. The inlet 62 is connected to the outlet 14 via a flow path and a valve V4, and the outlet 63 is connected to the introduction part 15, which will be described later, via a flow path and a valve V5. By separating and removing solid matter from the mixed liquid by the filter 6, it is possible to prevent clogging due to solid matter in the fine-meshed second coalescer 4 in the downstream stage.

[0042] As shown in FIG. 1 and FIG. 6 to FIG. 9, a circular cylindrical insertion portion 27 is provided on the peripheral wall portion 22 surrounding the second chamber 21 of the sealed container 2 so as to protrude horizontally from the outer circumferential surface. The insertion portion 27 allows the second coalescer 4 to be inserted sideways into the second chamber 21. A flange is formed at the tip of the insertion portion 27, and a plurality of through holes 28 are formed in the flange at equal intervals along the circumferential direction. A pair of fixing portions 29 is provided at intervals on the inner surface of the insertion portion 27, and a guide rail 72 is fixed to each of the pair of fixing portions 29. The pair of guide rails 72 extend parallel to each other in the horizontal direction from the insertion portion 27 toward the inner second chamber 21, and their ends are located in the vicinity of the peripheral wall portion 22 opposite to the insertion portion 27. The guide rail 72 supports the second coalescer 4 from below when the second coalescer 4 is inserted sideways from the insertion portion 27 into the second chamber 21. At least two guide rails 72 are required, and the number of guide rails 72 may be three or more.

[0043] As shown in Figures 2 and 5, the second coalescer 4 includes a porous coarse-grain filter 40 and inner and outer reinforcing members 41, 42 that reinforce the coarse-grain filter 40. The coarse-grain filter 40 has a function of capturing oil droplets that become turbid in the mixed liquid while the mixed liquid passes through a plurality of holes, and increasing the oil droplet diameter by bonding the oil droplets together and coarsening them. The coarse-grained oil droplets have increased buoyancy, so they separate from the mixed liquid by floating up after detaching from the second coalescer 4, and accumulate at the top of the second chamber 21 (below the partition plate 26).

[0044] The coarse-graining filter 40 captures small oil droplets that are turbid in the mixed liquid and coarsens them. The coarse-graining filter 40 can be a cylindrical body in which a sheet made of a fiber aggregate such as a woven fabric, a nonwoven fabric, or a knitted fabric is rolled into a cylindrical shape to a predetermined thickness, preferably a cylindrical body in which pleats are formed by overlapping a plurality of layers in the circumferential direction. The fibers constituting the fiber aggregate are not particularly limited, and may be natural fibers, synthetic fibers, glass fibers, or a combination of these, but it is preferable to use hydrophobic fibers such as glass fibers. By forming the coarse-graining filter 40 from hydrophobic fibers, small oil droplets can be effectively captured and coarsened. The size of the mesh (mesh opening) of the coarse-graining filter 40 is not particularly limited, but is, for example, 0.1 μm or more and 10 μm or less. The coarse-graining filter 40 is not limited to the above-mentioned fiber aggregate to cylindrical body, and various configurations known in the art can be used.

[0045] The outer reinforcing member 41 has a circular tubular shape larger than the coarse-grained filter 40, and the inner surface of the reinforcing member 41 abuts against the outer surface of the coarse-grained filter 40. The inner reinforcing member 42 has a circular tubular shape smaller than the coarse-grained filter 40, and the outer surface of the reinforcing member 42 abuts against the inner surface of the coarse-grained filter 40. The two reinforcing members 40, 41 are made of metal, for example, and have a plurality of through holes formed at equal intervals throughout their entire area to allow the mixed liquid to pass through.

[0046] 1 to 9, the second coalescer 4 is arranged sideways in the second chamber 21 with the axial direction of the coarse-grain filter 40 extending horizontally by using the mounting means 7. The mounting means 7 includes a fixed plate 70 attached to one end of the second coalescer 4, a presser plate 71 attached to the other end of the second coalescer 4 and sandwiching the second coalescer 4 between the fixed plate 70, and at least two guide rails 72 described above.

[0047] The fixing plate 70 has a circular shape, and its diameter is larger than that of the second coalescer 4 and is approximately the same size as the flange of the insertion part 27. A plurality of through holes 73 are formed at intervals along the circumferential direction near the outer periphery of the fixing plate 70. The fixing plate 70 is fixed to the insertion part 27 by passing bolts (not shown) through the respective through holes 28, 73 in a state where the fixing plate 70 is superimposed on the flange of the insertion part 27 and tightening them with nuts. A plurality of cylindrical parts 75 having female threads formed on the inner surface are provided at intervals in the circumferential direction on the inner surface of the fixing plate 70 at positions around the second coalescer 4. One end of a connecting rod 74 having male threads formed on the outer surface of both ends is connected to the plurality of cylindrical parts 75.

[0048] The pressing plate 71 has a circular shape, and its diameter is larger than that of the second coalescer 4 but smaller than that of the pressing plate 71. A plurality of through holes are provided at intervals in the circumferential direction on the inner surface of the pressing plate 71 at positions that are the periphery of the second coalescer 4 and that face the plurality of cylindrical portions 75 of the fixed plate 70. The pressing plate 71 presses the second coalescer 4 against the fixed plate 70 by passing the other ends of the connecting rods 74 protruding from the plurality of cylindrical portions 75 of the opposing fixed plate 70 through the plurality of through holes and tightening them with nuts 76 while sandwiching the second coalescer 4 between the pressing plate 71 and the fixed plate 70. As a result, the second coalescer 4 is sandwiched between the fixed plate 70 and the pressing plate 71.

[0049] A pair of notches 77 are formed on the outer periphery of the pressing plate 71. These notches 77 receive the corresponding guide rails 72, respectively, to allow the pressing plate 71 to slide on each guide rail 72 and to regulate the rotation of the pressing plate 71 (second coalescer 4) in the circumferential direction. The shape of the notches 77 can be various as long as it can fulfill the above-mentioned role.

[0050] Handles 78 and 79 are provided on the outer surfaces of the fixed plate 70 and the pressing plate 71, respectively. By gripping the handles 78 and 79, the second coalescer 4 can be easily lifted when inserting the second coalescer 4 from the insertion portion 27 into the second chamber 21 of the sealed container 2. The pressing plate 71 is placed on the pair of guide rails 72 so that the guide rails 72 fit into the notches 77 of the pressing plate 71, and the pressing plate 71 is slid on the pair of guide rails 72 while pushing in the second coalescer 4, making it easy to insert the second coalescer 4 from the insertion portion 27 into the second chamber 21 of the sealed container 2. The fixed plate 70 is fixed to the flange of the insertion portion 27, so that the second coalescer 4 can be arranged sideways in the second chamber 21.

[0051] A through hole 700 is formed in the center of the fixed plate 70, and a circular cylindrical introduction part 15 is provided so as to communicate with the through hole 700. The introduction part 15 is connected to the outflow part 63 of the filter 6 via a flow path and an on-off valve V5, and when the on-off valve V5 is opened, the mixed liquid from which solids have been removed by the filter 6 is supplied from the introduction part 15 to the hollow interior 43 of the coarse-grained filter 40 of the second coalescer 4. The mixed liquid is then conveyed to the coarse-grained filter 40 from the multiple through holes of the inner reinforcing material 41, and after passing through the coarse-grained filter 40 from the inner surface to the outer surface, is supplied to the second chamber 21 from the multiple through holes of the outer reinforcing material 40. The above-mentioned outlet part 14, introduction part 15, and the flow path connected thereto constitute a circulation path that guides the mixed liquid from the lower space 20B of the first chamber 20 of the sealed container 2 to the filter 6 and then supplies it to the second chamber 21.

[0052] 1, a circular cylindrical discharge part 16 for discharging the oil that has floated and separated from the mixed liquid from the second chamber 21 is provided in the peripheral wall part 22 surrounding the second chamber 21 of the sealed container 2 at a position above the second coalescer 4 and immediately below the partition plate 26. A flow path and an on-off valve V6 are connected to the discharge part 16, and the oil is discharged from the discharge part 16 to the outside of the sealed container 2 by opening the on-off valve V6.

[0053] A circular cylindrical discharge part 17 for discharging the treated mixed liquid from the second chamber 21, in which the oil has been separated and the oil concentration has been reduced, is provided at a position immediately above the bottom part 23 on the peripheral wall part 22 surrounding the second chamber 21 of the sealed container 2. A flow path and an on-off valve V7 are connected to the discharge part 17, and the treated mixed liquid is discharged from the discharge part 16 to the outside of the sealed container 2 by opening the on-off valve V7.

[0054] A circular cylindrical discharge part 18 for discharging drainage such as moisture and sludge that have settled in the second chamber 21 from the second chamber 21 is provided on the peripheral wall part 22 surrounding the second chamber 21 of the sealed container 2 at a position immediately above the bottom part 23 and at a position different in the circumferential direction from the discharge part 17. A flow path and an on-off valve V8 are connected to the discharge part 18, and the drainage is discharged from the discharge part 18 to the outside of the sealed container 2 by opening the on-off valve V8.

[0055] Next, a method for separating oil and water from a mixed liquid by the oil-water separator 1 of the present embodiment having the above-mentioned configuration will be described with reference to FIG. 10. First, the mixed liquid is supplied to the upper space 20A of the first chamber 20 in the sealed container 2, and first, the floating oil is separated due to the difference in specific gravity and accumulates at the top of the upper space 20A. The mixed liquid from which the floating oil has been removed passes through the first coalescer 3, and at this time, large oil droplets that are turbid in the mixed liquid are captured by the first coalescer 3, and the captured oil droplets combine with each other to become coarse particles. As a result, the coarse oil droplets are separated from the mixed liquid by increasing their buoyancy and floating up after detaching from the first coalescer 3, and are separated from the mixed liquid and accumulate at the top of the upper space 20A. The oil that has accumulated at the top of the upper space 20A is discharged from the discharge part 11 to the outside of the sealed container 2 by opening the on-off valve V1.

[0056] The mixed liquid after passing through the first coalescer 3 is supplied to the lower space 20B through the nozzle 5 supported by the support plate 25 that separates the upper space 20A and the lower space 20B of the first chamber 20. At this time, oil bubbles are generated in the mixed liquid after passing through the first coalescer 3, and a phenomenon occurs in which the space below the first coalescer 3 is filled with oil bubbles. However, the oil bubbles become smaller as they pass through the L-shaped nozzle 5 with a small diameter together with the mixed liquid, and the small oil bubbles rise after being discharged from the nozzle 5, so that the oil bubbles accumulate at the top of the lower space 20B (below the support plate 25), and a layer in which moisture accumulates is formed at the bottom of the lower space 20B. The oil bubbles accumulated at the top of the lower space 20B are discharged from the discharge part 12 to the outside of the sealed container 2 by opening the on-off valve V2. This makes it possible to suppress the oil bubbles from being supplied to the filter 6 or the second coalescer 4 through the discharge part 14.

[0057] The nozzle 5 is provided for the purpose of converting large oil bubbles generated in the mixed liquid after passing through the first coalescer 3 into small oil bubbles and facilitating discharge from the discharge section 12 to the outside of the sealed container 2. Here, the flow velocity V1 of the mixed liquid discharged from the lower end opening 50 of the nozzle 5 to the lower space 20B of the first chamber 20 is preferably 0.1 m / s or more and 2.0 m / s or less, and more preferably 0.1 m / s or more and 1.0 m / s or less, from the viewpoints of effectively reducing the oil bubbles discharged from the nozzle 5, reducing the pressure loss when the mixed liquid passes through the nozzle 5, and efficiently causing oil-water separation by preventing the flow of the mixed liquid in the lower space 20B of the first chamber 20 due to the discharge of the mixed liquid from the nozzle 5 from becoming intense.

[0058] The flow velocity V1 can be calculated from the volume of the mixed liquid flowing through the nozzle 5 per unit time and the cross-sectional area of ​​the nozzle 5, and the flow velocity V1 can be adjusted to the above-mentioned range by controlling the inner diameter of the nozzle 5, the flow rate of the mixed liquid, etc. Note that the flow velocity V1 is not limited to the above-mentioned range.

[0059] The mixed liquid supplied to the lower space 20B after passing through the first coalescer 3 is supplied from the sealed container 2 to the filter 6 via the outlet 14, where solids (including suspended solids (SS)) contained in the mixed liquid are separated and removed, and then the mixed liquid is supplied to the second coalescer 4 via the introduction part 15. This makes it possible to prevent the filter mesh of the second coalescer 4, which is the densest, from being clogged by solids contained in the mixed liquid.

[0060] The mixed liquid supplied to the second coalescer 4 passes through the second coalescer 4, and small oil droplets in the mixed liquid that were not captured by the first coalescer 3 are captured by the second coalescer 4, and the captured oil droplets combine with each other to form coarse particles. As a result, the coarse oil droplets are separated from the mixed liquid by increasing their buoyancy and rising after being detached from the second coalescer 4, and are accumulated at the top of the second chamber 21. The oil that has accumulated at the top of the second chamber 21 is discharged from the discharge part 16 to the outside of the sealed container 2 by opening the on-off valve V6.

[0061] When the mixed liquid is supplied from the introduction part 15 to the second coalescer 4, the mixed liquid is supplied to the hollow interior 43 of the coarse-grained filter 40, and then passes through the inner reinforcing material 41, the coarse-grained filter 40, and the outer reinforcing material 40 in that order (from inside to outside). At this time, if the flow of the mixed liquid in the hollow interior 43 of the coarse-grained filter 40 is fast, the mixed liquid will collide with the end (pressing plate 71) of the coarse-grained filter 40, and the flow flux around this end will be larger than other parts, which may cause oil leakage. Therefore, from the viewpoint of suppressing the above-mentioned oil leakage, the flow velocity V2 of the mixed liquid introduced from the introduction part 14 (circulation path) into the hollow interior of the coarse-grained filter 40 is preferably 0.1 m / s or more and 1.0 m / s or less, and preferably 0.3 m / s or more and 0.7 m / s or less.

[0062] The flow velocity V2 can be calculated from the volume of the mixed liquid flowing through the introduction part 14 per unit time and the cross-sectional area of ​​the introduction part 14, and the flow velocity V2 can be adjusted to the above-mentioned range by controlling the inner diameter of the introduction part 14, the flow rate of the mixed liquid, etc. Note that the flow velocity V2 is not limited to the above-mentioned range.

[0063] According to the oil-water separation device 1 of the present embodiment having the above-mentioned configuration, the height of the device can be reduced due to the two-stage configuration of the first coalescer 3 and the second coalescer 4. This reduces the workload when transporting the device, and also reduces the cost of the device itself.

[0064] Even if oil bubbles are generated in the mixed liquid after passing through the first coalescer 3, the oil bubbles are guided from the upper space 20A of the first chamber 20 to the lower space 20B through the nozzle 5, so that the oil bubbles become smaller, and the small oil bubbles rise to the top of the lower space 20B after being guided from the nozzle 5, so that the lower space 20B can be prevented from being filled with oil bubbles. Therefore, it is possible to prevent the oil bubbles from being supplied from the outlet portion 14 to the filter 6 and the second coalescer 4 together with the mixed liquid, so that the filtering process in the filter 6 is not hindered, and the coarse-grain filter 40 of the second coalescer 4 can be prevented from being clogged by the oil bubbles.

[0065] In addition, according to the oil-water separation device 1 of this embodiment, the flow velocity V1 of the mixed liquid discharged from the lower end opening 50 of the nozzle 5 to the lower space 20B of the first chamber 20 is 0.1 m / s or more and 2.0 m / s or less, thereby achieving the following effects: the oil bubbles discharged from the nozzle 5 can be effectively made smaller, the pressure loss when the mixed liquid passes through the nozzle 5 can be reduced, and the flow of the mixed liquid in the lower space 20B of the first chamber 20 due to the discharge of the mixed liquid from the nozzle 5 can be gentle, thereby efficiently causing oil-water separation.

[0066] In addition, according to the oil-water separation device 1 of this embodiment, the flow velocity V2 of the mixed liquid introduced from the introduction section 15 (circulation path) into the hollow interior 43 of the coarse-grained filter 40 of the second coalescer 4 is 0.1 m / s or more and 1.0 m / s or less, which has the effect of suppressing oil leakage at the end (pressure plate 71) of the coarse-grained filter 40.

[0067] In addition, according to the oil-water separation device 1 of this embodiment, the second coalescer 4 is arranged sideways in the second chamber 21 so that the axial direction of the coarse-grain filter 40 extends horizontally, but the second coalescer 4 is pushed toward the second chamber 21 while sliding it from the insertion part 27 on the guide rail 72 of the mounting means 7 via the pressing plate 71, and then the fixing plate 70 is fixed to the insertion part 27, so that the second coalescer 4 can be installed in the second chamber 21. Therefore, the workability of the installation work of the second coalescer 4 is improved, and the work burden can be reduced.

[0068] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0069] As a modified example, as shown in Fig. 11, the second coalescer 4 may have a sprinkler tube 44 inserted into the hollow interior 43 of the coarse-grain filter 40. The sprinkler tube 44 has one open end and the other closed end, and is inserted into the coarse-grain filter 40 so that the closed end is located near the pressing plate 71. The open end of the sprinkler tube 44 is fixed to the fixed plate 70, and the opening at one end of the sprinkler tube 44 is adjacent to the through-hole 700 of the fixed plate 70 and communicates with the introduction part 15. As a result, the mixed liquid from which solids have been removed by the filter 6 is introduced from the introduction part 15 (circulation path) into the hollow interior 45 of the sprinkler tube 44.

[0070] The liquid-spraying pipe 44 has a plurality of liquid-passing holes 46 formed at intervals along its axial and circumferential directions. The diameter of the liquid-passing holes 46, the interval between two adjacent liquid-passing holes 46 in the axial direction of the liquid-spraying pipe 44, and the interval between two adjacent liquid-passing holes 46 in the circumferential direction of the liquid-spraying pipe 44 are not particularly limited, but are preferably set so that the flow velocity V3 described later falls within a predetermined range.

[0071] In the modification shown in FIG. 11, the mixed liquid from which solids have been removed by the filter 6 is supplied from the introduction section 15 to the hollow interior 45 of the dispersion pipe 44 of the second coalescer 4. The mixed liquid is then supplied to the hollow interior 43 of the coarse-grained filter 40 through the multiple liquid passage holes 46 of the dispersion pipe 44, transmitted to the coarse-grained filter 40 through the multiple through holes of the inner reinforcing member 41, passed through the coarse-grained filter 40 from the inner surface to the outer surface, and then supplied to the second chamber 21 through the multiple through holes of the outer reinforcing member 40. As a result, when the mixed liquid is supplied from the introduction section 15 to the second coalescer 4, even if the flow of the mixed liquid is fast, the mixed liquid does not hit the end (pressing plate 71) of the coarse-grained filter 40 with force, and the mixed liquid is distributed evenly in the axial direction of the coarse-grained filter 40, so that leakage of oil around the end can be prevented.

[0072] Here, the flow velocity V3 of the mixed liquid discharged from the liquid passage hole 46 of the liquid diffusion pipe 44 to the hollow interior 43 of the coarse-grained filter 40 is preferably 0.4 m / s or more and 1.0 m / s or less, from the viewpoint of evenly distributing the mixed liquid in the axial direction of the coarse-grained filter 40.

[0073] The flow velocity V3 can be calculated from the volume of the mixed liquid flowing through the diffusion pipe 44 per unit time and the total cross-sectional area of ​​the liquid passage holes 46, and the flow velocity V2 can be adjusted to the above-mentioned range by controlling the diameter and number of the liquid passage holes 46, the flow rate of the mixed liquid, etc. Note that the flow velocity V3 is not limited to the above-mentioned range.

[0074] As another modified example, although not shown in the figures, a plurality of nozzles 5 may be supported on the support plate 25, and the mixed liquid may be directed from the upper space 20A of the first chamber 20 to the lower space 20B through the plurality of nozzles 5.

[0075] As another modified example (not shown), the second coalescer 4 may be disposed vertically in the second chamber 21 so that the axial direction of the coarse-grain filter 40 extends vertically.

[0076] As another modified example, although not shown in the drawings, a plurality of second coalescers 4 may be installed in the second chamber 21. [Explanation of symbols]

[0077] 1 Oil / water separator 2. Airtight containers 20 Room 1 20A Upper space of the first room 20B Lower space of second chamber 21 Second room 25 Support plate 3 First Coalescer 4. Second Coalescer 40 Coarse grain filter 43 Hollow interior of coarse grain filter 44 Hollow interior of the sprinkler tube 45 Liquid spray tube 46 Liquid hole 5 Nozzles 50 Nozzle bottom opening 51 Nozzle upper opening 6 Filter 7 Mounting means 71 Presser plate 72 Guide rail 77 Notch

Claims

1. An oil-water separation device that performs a process of floating and separating oil from a mixture of water and oil, an airtight container having an internal space partitioned into a first chamber and a second chamber above and below, and a mixed liquid is supplied to the first chamber; A first coalescer provided in the first chamber so that the mixed liquid passes through the first coalescer, which captures oil droplets in the mixed liquid and coarses them; A second coalescer is provided in the second chamber so that the mixed liquid after passing through the first coalescer passes through the second coalescer, and the second coalescer captures oil droplets in the mixed liquid and coarses them; a nozzle supported by a support plate that divides the first chamber into an upper space on the first coalescer side and a lower space on the second chamber side, the nozzle having an upper end opening that introduces the mixed liquid from the upper space and a lower end opening that discharges the mixed liquid to the lower space, the nozzle being L-shaped with the lower end opening facing horizontally; An oil-water separation device comprising:

2. 2. The oil-water separation device according to claim 1, wherein the flow velocity of the mixed liquid discharged from the lower end opening of the nozzle to the lower space is 0.1 m / s or more and 2.0 m / s or less.

3. The method further includes a filter for removing solid matter from the mixed liquid supplied from the lower space, The oil-water separation device described in claim 1 or 2, wherein the second coalescer includes a circular cylindrical coarse-grained filter, and is arranged sideways in the second chamber so that the axial direction of the coarse-grained filter extends horizontally, and is configured so that the mixed liquid after passing through the filter is introduced into the hollow interior of the coarse-grained filter.

4. 4. The oil-water separation device according to claim 3, wherein the flow velocity of the mixed liquid introduced into the hollow interior of the coarse-grain filter is 0.1 m / s or more and 1.0 m / s or less.

5. The second coalescer further includes a dispersion tube inserted into the hollow interior of the coarse-grain filter, and is configured so that the mixed liquid after passing through the filter is introduced into the hollow interior of the dispersion tube; 5. The oil-water separation device according to claim 3, wherein the diffusion pipe has a plurality of liquid passage holes formed at intervals along its axial and circumferential directions.

6. 6. The oil-water separation device according to claim 5, wherein the flow velocity of the mixed liquid discharged from the liquid passage hole of the diffusion pipe into the hollow interior of the coarse-grain filter is 0.4 m / s or more and 1.0 m / s or less.

7. The oil-water separation device according to any one of claims 3 to 6, wherein the coarse-grained filter is made of a hydrophobic material.

8. The sealed container is provided with an insertion portion capable of inserting the second coalescer sideways into the second chamber, The second coalescer is disposed laterally in the second chamber by an attachment means such that the axial direction of the coarse-grain filter extends horizontally; The mounting means includes at least two parallel guide rails extending horizontally inward from the insertion portion, and a presser plate attached to an end of the second coalescer on a side that is inserted first into the insertion portion, The pressure plate has at least two notches formed therein that receive corresponding guide rails to allow the pressure plate to slide on the at least two parallel guide rails and regulate the circumferential rotation of the second coalescer. An oil-water separation device as described in any one of claims 3 to 7.

9. An oil-water separation method for performing a process for separating oil from a mixture of water and oil by floating, comprising the steps of: a step of supplying the mixed liquid into an upper space of a sealed container, the upper space being partitioned into a first chamber and a second chamber above and below the first chamber by a support plate; A step of passing the mixed liquid through a first coalescer provided in the upper space to capture oil droplets in the mixed liquid and coarse them; a step of introducing the mixed liquid in the upper space that has passed through the first coalescer into an upper end opening of an L-shaped nozzle supported by the support plate and discharging the mixed liquid into the lower space from a lower end opening that faces a horizontal direction in the lower space; a step of passing the mixed liquid in the lower space through a second coalescer provided in the second chamber to capture oil droplets in the mixed liquid and coarsely disperse the oil droplets; The method for separating oil and water comprising the steps of:

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