WO2025054793A1 - Oil removal apparatus and flushing method therefor - Google Patents

Abstract

The present invention relates to the technical field of oil-water separation devices. Disclosed are an oil removal apparatus and a flushing method therefor. The oil removal apparatus comprises a tank body. A lower water distribution region, a first-stage material filling region, an intermediate water collection region, a second-stage material filling region, and an upper water collection region are arranged in sequence from bottom to top in the tank body. A water intake pipe and a water drainage pipe are provided on the tank body. Two layers of perforated plates are disposed in the intermediate water collection region in the tank body. The tank body is further provided with a first-stage water production pipe and a second-stage water production pipe. The water intake pipe, the water drainage pipe, the first-stage water production pipe, and the second-stage water production pipe each is provided with a valve. The tank body is further provided with manholes in one-to-one correspondence with the first-stage material filling region, the intermediate water collection region, and the upper water collection region. The tank body is provided with material discharging ports at the bottoms of the first-stage material filling region and the second-stage material filling region. Water intake and discharge can selectively be performed by means of different piping, and different flushing methods are selected for a first-stage filling material and a second-stage filling material, so that the oil removal effect is improved and the amount of backwashing wastewater is reduced. Material discharging and replacement can be performed on the first-stage filling material and the second-stage filling material by means of material discharging ports, so that the waste of activated carbon is reduced.

Description

Oil removal device and flushing method thereof Technical Field

The invention relates to the technical field of oil-water separation equipment, and in particular to an oil removal device and a flushing method thereof.

Background Art

Activated carbon filtration devices are often widely used in the field of oil-water separation. After the activated carbon in the commonly used activated carbon device absorbs oil substances in the water, it is easy to harden, resulting in reduced oil removal efficiency. Some activated carbon devices are equipped with a backwashing device, which is used to backwash the activated carbon to increase the service life of the activated carbon device. However, when the activated carbon device is used for oil-water separation, the upper and lower levels of the activated carbon deoiling column are severely differentiated with different operating time. When backwashing, the oil removal effect cannot be met or the activated carbon at the outlet end is not saturated with adsorption and is wasted.

For example, a Chinese utility model patent with authorization announcement number CN215828406U discloses a backwashable activated carbon oil removal device, including: an upper chamber unit area, a middle chamber activated carbon area and a lower chamber water collection area; the upper chamber unit area includes a water inlet, a manhole I, an HK tubular membrane unit, and a porous partition I; the middle chamber activated carbon area includes a backwash outlet, a manhole II, an activated carbon layer, a porous partition II, and a discharge port; the lower chamber water collection area includes a partition support tube, a water outlet, and a manhole III.

The above-mentioned backwashable activated carbon oil removal device uses backwashing to backwash the activated carbon layer, solving the problem of frequent unloading and backfilling of activated carbon. However, when using the activated carbon layer for oil removal, the upper and lower levels of the activated carbon oil removal column are severely differentiated. The water to be treated enters the activated carbon filtration device from the bottom. The activated carbon at the bottom is in contact with more oil substances and its compaction is more serious, while the upper activated carbon layer is much less compacted. During backwashing, the upper activated carbon is well washed but the lower activated carbon is still compacted. Continuing to remove oil cannot meet the oil removal effect, and unloading the activated carbon will cause the activated carbon to be unsaturated and wasted.

Summary of the invention

The purpose of the present invention is to provide an oil removal device to solve the problem that the activated carbon column of the activated carbon filter device in the prior art is differentiated into two levels, which cannot meet the oil removal effect or causes waste of activated carbon during backwashing; the present invention also provides a flushing method for the oil removal device.

In order to achieve the above-mentioned object, the present invention provides an oil removal device, including a tank body, wherein a lower water distribution area, a primary filler area, an intermediate water collection area, a secondary filler area and an upper water collection area are sequentially arranged from bottom to top in the tank body, wherein the primary filler area is used to fill a first filler, and the secondary filler area is used to fill a second filler;

The tank body is provided with a water inlet pipe connected with the lower water distribution area, and a drainage pipe for backwashing is also arranged in parallel on the water inlet pipe;

A porous plate is arranged in the middle water collection area of the tank body, and two layers of the porous plates are arranged at intervals along the vertical direction of the tank body. A support column is connected between the two layers of the porous plates. A primary water production pipe connected to the space between the two layers of the porous plates is also arranged on the tank body.

The tank body is provided with a secondary water production pipe connected with the upper water collection area, and valves are arranged on the water inlet pipe, the drainage pipe, the primary water production pipe and the secondary water production pipe;

The tank body is also provided with manholes corresponding to the primary filling area, the middle water collection area and the upper water collection area. The tank body is provided with discharge ports at the bottom of the primary filling area and the bottom of the secondary filling area.

Preferably, each water passage hole of the two layers of the porous plates is provided with a water cap.

Preferably, the water caps on the two layers of the porous plates are arranged in opposite directions.

Preferably, the lower water distribution area is arranged with a water distribution plate, and the water distribution plate is used to separate the lower water distribution area from the primary filling area. The water distribution plate is evenly spaced with a plurality of water distribution holes, and the water distribution plate is a dome-shaped curved surface structure, and the top of the water distribution plate is bent toward the direction of the primary filling area.

Preferably, the first filler comprises a quartz sand layer, an activated carbon layer and a ceramsite layer arranged in sequence from bottom to top.

Preferably, the second filler comprises an activated carbon layer and a ceramsite layer arranged in sequence from bottom to top.

Preferably, a wire-wrapped screen tube is also arranged in the upper water collection area, and the wire-wrapped screen tube is connected to the secondary water production pipe.

Preferably, the tank body is provided with sight glasses at the top of the primary filling area and the top of the secondary filling area.

Preferably, the top of the tank body is also provided with an exhaust hole.

The present invention also provides a flushing method, which is applied to the oil removal device of any of the above technical solutions, comprising:

When only the primary packing area is being washed, the valves on the water inlet pipe and the primary water production pipe are opened, and the valves on the drain pipe and the secondary water production pipe are closed. The cleaning liquid enters the tank body through the water inlet pipe and is discharged from the tank body through the primary water production pipe.

When backwashing only the primary packing area, open the valves on the drain pipe and the primary water production pipe, and close the valves on the water inlet pipe and the secondary water production pipe. The cleaning liquid enters the tank body through the primary water production pipe and is discharged from the tank body through the drain pipe.

When only the secondary packing area is being washed, close the valves on the water inlet pipe and the drain pipe, and open the valves on the primary and secondary water production pipes. The cleaning liquid enters the tank body through the primary water production pipe and is discharged from the tank body through the secondary water production pipe.

When backwashing only the secondary packing area, close the valves on the water inlet pipe and the drain pipe, and open the valves on the primary and secondary water production pipes. The cleaning liquid enters the tank body through the secondary water production pipe and is discharged from the tank body through the secondary and primary water production pipes.

When washing the primary filling area and the secondary filling area at the same time, open the valves on the water inlet pipe and the secondary water production pipe, and close the valves on the drain pipe and the primary water production pipe. The cleaning liquid enters the tank body through the water inlet pipe and is discharged from the tank body through the secondary water production pipe.

When backwashing the primary packing area and the secondary packing area at the same time, open the valves on the drain pipe and the secondary water production pipe, and close the valves on the water inlet pipe and the primary water production pipe. The cleaning liquid enters the tank body through the secondary water production pipe and is discharged from the tank body through the drain pipe.

When backwashing the primary filler area and forward washing the secondary filler area, open the valves on the drain pipe, the primary water production pipe and the secondary water production pipe, and close the valve on the water inlet pipe. The cleaning liquid enters the tank body through the primary water production pipe and is discharged from the tank body through the drain pipe and the secondary water production pipe.

Compared with the prior art, an oil removal device and a flushing method thereof according to an embodiment of the present invention have the following beneficial effects: a primary filling area, an intermediate water collection area and a secondary filling area are formed in the tank body from bottom to top, the primary filling area and the secondary filling area are separated by the intermediate water collection area, and a primary water production pipe and a secondary water production pipe are provided to produce water from the intermediate water collection area and the upper water collection area respectively, so as to generate water filtered by different filling areas; when flushing is required, water can be supplied from different pipelines such as the primary water production pipe, the secondary water production pipe and the water inlet pipe by controlling valves on different pipelines according to the adsorption effect, and water can be discharged from different pipelines at the same time, and the primary filling area and the secondary filling area can be washed forward or backwashed separately or washed forward or backwashed simultaneously; different flushing methods are selected for the primary filling and the secondary filling, so as to improve the oil removal effect and reduce the amount of backwash wastewater; when unloading is required, the primary filling and the secondary filling can be unloaded and replaced separately through the unloading port, that is, part of the activated carbon can be replaced to reduce the waste of activated carbon.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of an oil removal device according to the present invention.

In the figure, 1, tank body, 2, lower water distribution area, 3, primary filling area, 4, middle water collection area, 5, secondary filling area, 6, upper water collection area, 7, water inlet pipe, 8, drainage pipe, 9, porous plate, 10, support column, 11, primary water production pipe, 12, secondary water production pipe, 13, valve, 14, manhole, 15, discharge port, 16, water cap, 17, water distribution plate, 18, quartz sand layer, 19, activated carbon layer, 20, expanded clay layer, 21, wire screen pipe, 22, sight glass, 23, exhaust hole.

DETAILED DESCRIPTION

The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

A preferred embodiment of an oil removal device of the present invention, as shown in Figure 1, includes a tank body 1, which is a cylindrical metal structure. The top and bottom of the tank body 1 are both arc-shaped, and the bottom of the tank body 1 is also provided with multiple legs to support the tank body 1.

The tank body 1 is provided with a lower water distribution area 2, a primary filling area 3, an intermediate water collection area 4, a secondary filling area 5 and an upper water collection area 6 from bottom to top. The primary filling area 3, the intermediate water collection area 4, the secondary filling area 5 and the upper water collection area 6 are interconnected so that water can flow through them in sequence. The treated water enters the tank body 1 and is distributed. The primary filling area 3 is used to fill the first filler, the middle water collection area 4 is used to collect the clean water after adsorption and filtration by the first filler in the primary filling area 3, the secondary filling area 5 is used to fill the second filler, and the upper water collection area 6 is used to collect the clean water after adsorption and filtration by the second filler in the secondary filling area 5.

The bottom of the tank body 1 is provided with a water inlet pipe 7, which is connected to the lower water distribution area 2. The water inlet pipe 7 is used to connect to an external storage device for treated water to introduce the treated water into the lower water distribution area 2. A drain pipe 8 is also arranged in parallel on the water inlet pipe 7, which is used to discharge the cleaning liquid during backwashing or backflushing. At this time, after closing the valve 13 on the water inlet pipe 7, it is not necessary to drain the water from the water inlet pipe 7, and it is not necessary to disconnect the water inlet pipe 7 from the external water to be treated. The water inlet pipe 7 and the drain pipe 8 converge into one pipe at the bottom of the tank body 1, which can reduce the number of openings on the tank body 1, reduce the manufacturing cost of the device and the leakage point.

A porous plate 9 is arranged in the middle water collection area 4 in the tank body 1. The porous plate 9 has two layers. The two layers of porous plates 9 are arranged at intervals along the vertical direction of the tank body 1, and a support column 10 is connected between the two layers of porous plates 9. The two layers of porous plates 9 play the role of isolating the primary filling area 3 and the secondary filling area 5, that is, the space between the two layers of porous plates 9 forms the middle water collection area 4. At the same time, the porous plates 9 can also allow the water flow purified by the primary filling area 3 to enter the secondary filling area 5. A support column 10 is also connected between the two layers of porous plates 9. There are multiple support columns 10 and they are distributed at intervals along the circumference of the tank body 1. The support columns 10 are used to connect and assemble the two layers of porous plates 9.

The tank body 1 is also provided with a primary water production pipe 11, which is connected to the space between the two layers of porous plates 9, that is, the primary water production pipe 11 is connected to the middle water collection area 4. When the oil removal effect is achieved, the water flow purified by the primary packing area 3 can flow out through the primary water production pipe 11. In addition, according to needs, the primary water production pipe 11 can also be changed to the forward wash water inlet of the secondary packing area 5 or the backwash water inlet of the primary packing area 3, so as to realize multiple flushing methods.

The tank body 1 is also provided with a secondary water production pipe 12, which is connected to the upper water collection area 6 and is used to supply the water flow after being purified by the secondary packing area 5. In addition, as required, the secondary water production pipe 12 can also be changed to the backwash water inlet of the secondary packing area 5 or the backwash inlet of the primary packing area 3 and the secondary packing area 5, so as to realize multiple flushing methods. In this embodiment, the primary drainage pipe 8 and the secondary drainage pipe 8 are connected to each other through a connecting pipe. A valve 13 is also provided to change the flow direction of the purified water and the cleaning liquid as required.

Valves 13 are arranged on the water inlet pipe 7, the drainage pipe 8, the primary water production pipe 11, and the secondary water production pipe 12. The valves 13 are used to control the on-off of the corresponding pipelines. When the primary filling area 3 and the secondary filling area 5 are flushed in different ways, the valves 13 of the corresponding pipelines can be controlled to control the flow direction of the cleaning liquid, and the primary water production pipe 11 and the secondary water production pipe 12 can be turned into the water inlet of the cleaning liquid, or the drainage pipe 8 can be opened or closed, so as to perform forward washing or backwashing on the primary filling area 3 and the secondary filling area 5.

The tank body 1 is also provided with manholes 14 corresponding to the primary filling area 3, the intermediate water collection area 4, and the upper water collection area 6. The manhole 14 on the primary filling area 3 is for operators to enter and arrange filling in the filling area. The manhole 14 in the intermediate water collection area 4 is for operators to enter the intermediate water collection area 4 to repair and replace the porous plate 9 in the intermediate water collection area 4. The manhole 14 in the upper water collection area 6 is for operators to enter the tank body 1 from the top, and the upper water collection area 6 is connected to the secondary filling area 5, for placing filling in the secondary filling area 5, and for repairing and replacing the structure in the upper water collection area 6.

The tank body 1 is provided with discharge ports 15 at the bottom of the primary filler area 3 and the bottom of the secondary filler area 5. The discharge ports 15 are used to discharge the first filler and the second filler that are deactivated or adsorbed to saturation and cannot be regenerated. When the oil removal and adsorption effect of the first filler in the primary filler area 3 or the second filler in the secondary filler area 5 is reduced and needs to be replaced, the discharge ports 15 can be opened respectively, and the first filler and the second filler can be replaced synchronously or alternately, saving activated carbon.

The oil removal device forms a primary packing area 3, an intermediate water collection area 4 and a secondary packing area 5 from bottom to top in the tank body 1, and uses the intermediate water collection area 4 to separate the primary packing area 3 from the secondary packing area 5. At the same time, a primary water production pipe 11 and a secondary water production pipe 12 are arranged to produce water from the intermediate water collection area 4 and the upper water collection area 6 respectively, so as to generate water filtered by different packing areas. When flushing is required, water can be selected to be fed from different pipelines such as the primary water production pipe 11, the secondary water production pipe 12 and the water inlet pipe 7 according to the adsorption effect by controlling the valves 13 on different pipelines, and water can be discharged from different pipelines at the same time, and the primary packing area 3 and the secondary packing area 5 can be washed forward or backwashed separately or simultaneously. Different flushing methods are selected for the primary packing and the secondary packing to improve the oil removal effect and reduce the amount of backwash wastewater. When unloading is required, the primary packing and the secondary packing can be unloaded and replaced separately through the unloading port 15, that is, part of the activated carbon can be replaced. Reduce the waste of activated carbon.

Preferably, each water passage hole of the two layers of porous plates 9 is provided with a water cap 16 .

Water caps 16 are provided on each water passage hole of the two-layer porous plate 9. The water caps 16 can filter impurities in the water and intercept the lower layer suspended matter carried in the water flow after filtering through the primary filler area 3 from entering the porous plate 9 and the secondary filler area 5, thereby protecting the filler in the secondary filler area 5 and extending the service life of the second filler.

Preferably, the water caps 16 on the two layers of porous plates 9 are arranged in opposite directions.

The water cap 16 of the lower porous plate 9 is located at the lower side, and the water cap 16 of the upper porous plate 9 is located at the upper side. The water cap 16 is convenient for operators to enter the middle water collection area 4 through the manhole 14 to replace and repair the water cap 16.

Preferably, the lower water distribution area 2 is arranged with a water distribution plate 17, which is used to separate the lower water distribution area 2 from the primary filling area 3. A plurality of water distribution holes are evenly spaced on the water distribution plate 17. The water distribution plate 17 is a dome-shaped curved structure, and the top of the water distribution plate 17 is bent toward the direction of the primary filling area 3.

The water distribution plate 17 serves to separate the lower water distribution area 2 from the primary filling area 3, and can support the first filler in the primary filling area 3. At the same time, the water to be treated can be evenly distributed into the filling area through the multiple water distribution holes on the water distribution plate 17, so that the water is evenly adsorbed by the first filler.

Preferably, the first filler includes a quartz sand layer 18, an activated carbon layer 19 and a ceramsite layer 20 which are arranged in sequence from bottom to top.

The quartz sand layer 18 has a further water replenishing effect on the water flow entering through the water distribution plate 17, and can also preliminarily intercept oily particles and other impurities to avoid blocking the water flow channel; the activated carbon layer 19 can adsorb oily particles in the water for oil removal; the ceramsite layer 20 is used to compact the activated carbon to avoid the suspension of activated carbon particles, which can improve the oil removal effect of the activated carbon layer 19.

Preferably, the second filler includes an activated carbon layer 19 and a ceramsite layer 20 arranged in sequence from bottom to top.

The activated carbon layer 19 of the second filler can absorb oily particles in the water for degreasing, and the ceramsite layer 20 is used to compact the activated carbon to prevent the activated carbon particles from suspending, thereby improving the degreasing effect of the activated carbon layer 19. Since the porous plate 9 of the middle water collection area 4 has a water distribution effect, the second filler does not need to be arranged with quartz sand like the first filler.

Preferably, a wire-wrapped screen tube 21 is further arranged in the upper water collection area 6 , and the wire-wrapped screen tube 21 is connected to the secondary water production pipe 12 .

The wire-wound screen tube 21 is symmetrically installed in the upper water collection area 6 and is located on the portion of the secondary water production pipe 12 extending into the tank body 1. The wire-wound drying circle has the effect of uniform water collection and water discharge. In this embodiment, the wire-wound screen tube 21 is a wedge-shaped wire-wound tube.

Preferably, the tank body 1 is provided with sight glasses 22 at the top of the primary filling area 3 and the top of the secondary filling area 5 .

In this embodiment, the sight glass 22 is arranged at the junction of the ceramsite layer 20 and the activated carbon layer 19 of the primary filling area 3 and the secondary filling area 5, so that the compacted lower layer of the activated carbon layer 19 can be observed at any time, and the flushing frequency and flushing flow rate can be formulated according to the observed structure. The states of the activated carbon layer 19 of the first filler and the second filler are observed by two sight glasses 22, respectively, so that the flushing and replacement plans for the activated carbon in the primary filling area 3 and the secondary filling area 5 can be formulated respectively.

Preferably, a vent hole 23 is also provided on the top of the tank body 1 .

The exhaust hole 23 is located at the top of the tank body 1 . When gas is generated during the initial water intake or oil removal process, the gas in the tank body 1 can be discharged to balance the pressure in the tank body 1 .

A preferred embodiment of a flushing method of the present invention is applied to the oil removal device of any of the above embodiments, and includes multiple flushing methods, and the specific selection method can be determined according to water quality and requirements. The flushing method specifically includes:

When only the primary filling area 3 is being washed, the valves 13 on the water inlet pipe 7 and the primary water production pipe 11 are opened, and the valves 13 on the drain pipe 8 and the secondary water production pipe 12 are closed. The cleaning liquid enters the tank body 1 through the water inlet pipe 7 and is discharged from the tank body 1 through the primary water production pipe 11.

When backwashing only the primary filling area 3, the valves 13 on the drain pipe 8 and the primary water production pipe 11 are opened, and the valves 13 on the water inlet pipe 7 and the secondary water production pipe 12 are closed, and the cleaning liquid enters the tank body 1 through the primary water production pipe 11 and is discharged from the tank body 1 through the drain pipe 8.

When only the secondary filling area 5 is being washed, the valves 13 on the water inlet pipe 7 and the drain pipe 8 are closed, and the valves 13 on the primary water production pipe 11 and the secondary water production pipe 12 are opened, and the cleaning liquid enters the tank body 1 through the primary water production pipe 11 and is discharged from the tank body 1 through the secondary water production pipe 12.

When backwashing only the secondary packing area 5, close the valves 13 on the water inlet pipe 7 and the drain pipe 8, and The valves 13 on the primary water production pipe 11 and the secondary water production pipe 12 are opened, and the cleaning liquid enters the tank body 1 through the secondary water production pipe 12 and is discharged from the tank body 1 through the secondary water production pipe 12 and the primary water production pipe 11.

When washing the primary filling area 3 and the secondary filling area 5 at the same time, the valves 13 on the water inlet pipe 7 and the secondary water production pipe 12 are opened, and the valves 13 on the drain pipe 8 and the primary water production pipe 11 are closed, and the cleaning liquid enters the tank body 1 through the water inlet pipe 7 and is discharged from the tank body 1 through the secondary water production pipe 12.

When backwashing the primary filling area 3 and the secondary filling area 5 at the same time, the valves 13 on the drain pipe 8 and the secondary water production pipe 12 are opened, and the valves 13 on the water inlet pipe 7 and the primary water production pipe 11 are closed, and the cleaning liquid enters the tank body 1 through the secondary water production pipe 12 and is discharged from the tank body 1 through the drain pipe 8.

When backwashing the primary filling area 3 and forward washing the secondary filling area 5, open the valves 13 on the drain pipe 8, the primary water production pipe 11 and the secondary water production pipe 12, and close the valve 13 on the water inlet pipe 7. The cleaning liquid enters the tank body 1 through the primary water production pipe 11 and is discharged from the tank body 1 through the drain pipe 8 and the secondary water production pipe 12.

In summary, the embodiment of the present invention provides an oil removal device and a flushing method thereof, which respectively form a primary filling area, an intermediate water collection area and a secondary filling area in a tank body from bottom to top, and use the intermediate water collection area to separate the primary filling area and the secondary filling area, and at the same time, a primary water production pipe and a secondary water production pipe are provided to produce water from the intermediate water collection area and the upper water collection area respectively, to generate water filtered by different filling areas. When flushing is required, water can be supplied from different pipelines such as the primary water production pipe, the secondary water production pipe, and the water inlet pipe by controlling valves on different pipelines according to the adsorption effect, and water can be discharged from different pipelines at the same time, and the primary filling area and the secondary filling area can be washed forward or backwashed separately or washed forward or backwashed at the same time, and different flushing methods are selected for the primary filler and the secondary filler to improve the oil removal effect and reduce the amount of backwash wastewater. When unloading is required, the primary filler and the secondary filler can be unloaded and replaced separately through the unloading port, that is, part of the activated carbon can be replaced to reduce the waste of activated carbon.

The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims (10)

An oil removal device, characterized in that it comprises a tank body (1), wherein the tank body (1) is provided with a lower water distribution area (2), a primary filling area (3), an intermediate water collection area (4), a secondary filling area (5) and an upper water collection area (6) which are interconnected from bottom to top, wherein the primary filling area (3) is used to fill a first filling material, and the secondary filling area (5) is used to fill a second filling material; The tank body (1) is provided with a water inlet pipe (7) connected to the lower water distribution area (2), and a drainage pipe (8) for backwashing is also arranged in parallel on the water inlet pipe (7); A porous plate (9) is arranged in the middle water collection area (4) in the tank body (1), and the porous plate (9) is arranged in two layers at intervals along the vertical direction of the tank body (1), and a support column (10) is connected between the two layers of the porous plates (9). The tank body (1) is also provided with a primary water production pipe (11) that is connected to the space between the two layers of the porous plates (9); The tank body (1) is provided with a secondary water production pipe (12) connected to the upper water collection area (6); valves (13) are arranged on the water inlet pipe (7), the drainage pipe (8), the primary water production pipe (11), and the secondary water production pipe (12); The tank body (1) is also provided with manholes (14) corresponding to the primary filling area (3), the intermediate water collection area (4), and the upper water collection area (6), and the tank body (1) is provided with discharge ports (15) at the bottom of the primary filling area (3) and the bottom of the secondary filling area (5). The oil removal device according to claim 1 is characterized in that each water passage hole of the two layers of the porous plates (9) is provided with a water cap (16). The oil removal device according to claim 2 is characterized in that the water caps (16) on the two layers of the porous plates (9) are arranged in opposite directions. The oil removal device according to any one of claims 1 to 3 is characterized in that the lower water distribution area (2) is arranged with a water distribution plate (17), the water distribution plate (17) is used to separate the lower water distribution area (2) from the primary filling area (3), and a plurality of water distribution holes are evenly distributed on the water distribution plate (17), the water distribution plate (17) is a dome-shaped curved surface structure, and the top of the water distribution plate (17) is bent toward the direction of the primary filling area (3). The oil removal device according to any one of claims 1 to 3, characterized in that the first filler comprises a quartz sand layer (18), an activated carbon layer (19) and a ceramsite layer (20) arranged in sequence from bottom to top. The oil removal device according to any one of claims 1 to 3 is characterized in that the second filler comprises an activated carbon layer (19) and a ceramsite layer (20) arranged in sequence from bottom to top. The oil removal device according to any one of claims 1 to 3 is characterized in that a wire-wrapped screen tube (21) is further arranged in the upper water collection area (6), and the wire-wrapped screen tube (21) is connected to the secondary water production pipe (12). The oil removal device according to any one of claims 1 to 3 is characterized in that the tank body (1) is provided with sight glasses (22) at the top of the primary filling area (3) and the top of the secondary filling area (5). The oil removal device according to any one of claims 1 to 3 is characterized in that an exhaust hole (23) is also provided on the top of the tank body (1). A flushing method, applied to the oil removal device according to any one of claims 1 to 9, characterized in that it comprises: When only the primary filling area (3) is being washed, the valves (13) on the water inlet pipe (7) and the primary water production pipe (11) are opened, and the valves (13) on the drain pipe (8) and the secondary water production pipe (12) are closed, so that the cleaning liquid enters the tank body (1) through the water inlet pipe (7) and is discharged from the tank body (1) through the primary water production pipe (11); When backwashing only the primary filling area (3), the valves (13) on the drain pipe (8) and the primary water production pipe (11) are opened, and the valves (13) on the water inlet pipe (7) and the secondary water production pipe (12) are closed, so that the cleaning liquid enters the tank body (1) through the primary water production pipe (11) and is discharged from the tank body (1) through the drain pipe (8); When only the secondary filling area (5) is being washed, the valves (13) on the water inlet pipe (7) and the drain pipe (8) are closed, and the valves (13) on the primary water production pipe (11) and the secondary water production pipe (12) are opened, so that the cleaning liquid enters the tank body (1) through the primary water production pipe (11) and is discharged from the tank body (1) through the secondary water production pipe (12); When backwashing only the secondary packing area (5), close the water inlet pipe (7) and the drain pipe (8). The valve (13) is closed, and the valves (13) on the primary water production pipe (11) and the secondary water production pipe (12) are opened, so that the cleaning liquid enters the tank body (1) through the secondary water production pipe (12) and is discharged from the tank body (1) through the secondary water production pipe (12) and the primary water production pipe (11); When the primary filling area (3) and the secondary filling area (5) are being washed simultaneously, the valves (13) on the water inlet pipe (7) and the secondary water production pipe (12) are opened, and the valves (13) on the drain pipe (8) and the primary water production pipe (11) are closed, so that the washing liquid enters the tank body (1) through the water inlet pipe (7) and is discharged from the tank body (1) through the secondary water production pipe (12); When backwashing the primary filling area (3) and the secondary filling area (5) at the same time, the valves (13) on the drain pipe (8) and the secondary water production pipe (12) are opened, and the valves (13) on the water inlet pipe (7) and the primary water production pipe (11) are closed, and the cleaning liquid enters the tank body (1) through the secondary water production pipe (12) and is discharged from the tank body (1) through the drain pipe (8); When backwashing the primary filling area (3) and forward washing the secondary filling area (5), the valves (13) on the drain pipe (8) and the primary water production pipe (11) and the secondary water production pipe (12) are opened, and the valve (13) on the water inlet pipe (7) is closed, so that the cleaning liquid enters the tank body (1) through the primary water production pipe (11) and is discharged from the tank body (1) through the drain pipe (8) and the secondary water production pipe (12).