A multi-stage sewage treatment device and treatment method for petrochemical refining

Abstract

The present application relates to the technical field of sewage treatment, and specifically discloses a multi-stage sewage treatment device and treatment method for petrochemical refining, including a filtration tank, an oil slick removal section, a slag and stone removal section, and a drain valve; the filtration tank is provided with a water inlet and a water outlet; the oil slick removal section is located in the filtration tank and arranged in the upper part of the filtration tank. The oil slick removal section has a blocking state and a passing state. When the oil slick removal section is in the blocking state, the oil slick removal section blocks the upper part of the filtration tank. When the oil slick removal section is in the passing state, the oil slick removal section allows the refining sewage to pass through; the slag and stone removal section is arranged at the bottom of the filtration tank and spaced from the bottom end of the filtration tank, and the slag and stone removal section is used to remove the slag and stone in the sewage in the filtration tank; the drain valve is connected to the water outlet of the filtration tank and is used to discharge the filtered sewage. The present application has the effects of reducing the influence of slag and stone on the subsequent sewage classification treatment device and reducing the interference of waste oil in the sewage on the subsequent sewage classification treatment device.

Description

Technical Field

[0001] The present application relates to the technical field of sewage treatment, and particularly relates to a multi-stage sewage treatment device and treatment method for petrochemical refining. Background Art

[0002] Petrochemical refining is a process of evaporating and fractionating hydrocarbon compounds in crude oil by physical or chemical means according to different temperatures. During the refining process, wastewater is generated in the steps of water injection, condensation, and water washing. The wastewater mixes during the discharge process to form sewage. The sewage contains impurities such as waste oil, slag particles, water-soluble organic matter, microorganisms, and inorganic salts.

[0003] In the existing sewage treatment process, the sewage needs to be treated in multiple stages so that it can be discharged after meeting the discharge standards. The existing sewage treatment methods include separation methods such as adsorption, membrane separation, oxidation separation, and emulsion separation to separate impurities in the sewage.

[0004] In the existing sewage treatment process, the larger slag in the sewage needs to be filtered first before the subsequent multi-stage sewage treatment can be carried out, so as to reduce the probability of the slag damaging the subsequent multi-stage sewage treatment device. At the same time, the waste oil contained in the sewage will also interfere with the subsequent multi-stage sewage treatment steps. Summary of the Invention

[0005] In order to reduce the influence of slag on the subsequent multi-stage sewage treatment device and reduce the interference of waste oil in the sewage on the subsequent multi-stage sewage treatment device, the present application provides a multi-stage sewage treatment device and treatment method for petrochemical refining.

[0006] The multi-stage sewage treatment device and treatment method for petrochemical refining provided by the present application adopt the following technical solutions:

[0007] A multi-stage sewage treatment device for petrochemical refining, comprising:

[0008] A filter tank, provided with a water inlet and a water outlet;

[0009] An oil skimming part, located in the filter tank and arranged at the upper part of the filter tank. The oil skimming part has a blocking state and a passing state. When the oil skimming part is in the blocking state, the oil skimming part blocks the upper part of the filter tank. When the oil skimming part is in the passing state, the oil skimming part allows the refining sewage to pass through;

[0010] A slag removal part, arranged at the bottom of the filter tank and spaced from the bottom end of the filter tank. The slag removal part is used to remove slag in the sewage in the filter tank;

[0011] A drain valve, connected to the water outlet of the filter tank, for discharging the filtered sewage.

[0012] By adopting the above technical scheme, sewage is introduced into the filter tank through the water inlet, and the floating oil removal unit allows sewage to enter the filter tank in a passable state. The floating oil floats on the top of the filter tank due to the buoyancy, and the slag and stone in the sewage settles below the filter tank under the action of gravity. At this time, the floating oil removal unit changes from a passable state to a blocked state, isolating the floating oil floating on the top of the filter tank, and the slag and stone removal unit removes the slag and stone settled at the bottom of the filter tank, and then opens the drain valve to discharge the sewage separated from the slag and floating oil, thereby facilitating the multi-stage treatment of petrochemical refinery sewage by grading the sewage, reducing the impact of the slag and stone on the subsequent sewage grading treatment device, and reducing the interference of the waste oil in the sewage on the subsequent sewage grading treatment device.

[0013] Optionally, the floating oil removal part includes a positioning frame and a deformer, the positioning frame is fixedly connected to the slot wall of the filter slot, an installation cavity is opened inside the positioning frame, the deformer is arranged in the installation cavity, a plurality of sewage through holes are opened in the middle part of the positioning frame, a sliding guide groove is opened on the hole wall of the sewage through hole, and the deformer is slidably connected to the sliding guide groove.

[0014] By adopting the above technical solution, the floating oil removal part is positioned by the positioning frame, and when the floating oil removal part is in the passing state, the deformer is in the installation cavity, so that sewage passes through the sewage through hole. When the floating oil removal part is in the blocking state, the deformer is connected to the sliding guide groove from the installation cavity, thereby blocking the sewage through hole, thereby achieving the effect of isolating the floating oil.

[0015] Optionally, the deformer includes a winding motor, a winding roller and a deformable sealing piece, the winding motor and the winding roller are arranged in the installation cavity, the positioning frame is provided with a winding groove connecting the sliding guide groove, the installation cavity and the sewage through hole, the two ends of the deformable sealing piece are in sliding contact with the groove wall of the winding groove, and the two sides of the deformable sealing piece are in sliding contact with the groove wall of the sliding guide groove.

[0016] By adopting the above technical solution, the deformer controls the rotation of the winding roller through the winding motor. The rotation of the winding roller changes the deformable sealing piece from the state of being wound on the winding roller to the state of being released from the winding roller. When the winding roller is released, the deformable sealing piece slides in the sliding guide groove to complete the sealing of the sewage through hole.

[0017] Optionally, a floating oil discharge device is connected to one side wall of the filter tank, and the floating oil discharge device is arranged above the positioning frame. The floating oil discharge device is used to slide against the positioning frame and the deformation sealing plate. A floating oil discharge outlet is opened on the side wall of the filter tank away from the floating oil discharge device, and the floating oil discharge outlet is connected to a discharge control valve.

[0018] By adopting the above technical solution, the floating oil discharge device is slidably connected to the positioning frame. When the sewage enters the filter tank, the discharge control valve is closed. When the floating oil removal part is in a blocked state, the discharge control valve is opened. The floating oil discharge device slidably abuts against the positioning frame and the deformation blocking piece to discharge the floating oil above the floating oil removal part through the discharge control valve.

[0019] Optionally, the floating oil discharge device includes a telescopic push rod, a connecting plate and an oil absorbing sponge, one end of the telescopic push rod is connected to one side of the filter tank, the connecting plate is fixedly connected to the other end of the telescopic push rod, the bottom end gap of the connecting plate is arranged above the positioning frame, the oil absorbing sponge is connected to the side of the connecting plate away from the telescopic push rod, and the oil absorbing sponge is used to slide against the deformation sealing plate.

[0020] By adopting the above technical solution, when the floating oil discharge device is working, the telescopic push rod is extended and retracted to drive the connecting plate to move, thereby driving the oil-absorbing sponge to move. The oil-absorbing sponge abuts against the positioning frame and the deformation sealing piece, thereby pushing the floating oil on the positioning frame and the deformation sealing piece toward the discharge control valve, and discharging the floating oil from the discharge control valve.

[0021] Optionally, the gravel removal part includes a gravel filter frame, a gravel plugging piece and a gravel filter plate, the gravel filter frame is connected to the tank wall of the filter tank, the gravel plugging piece is rotatably connected to the gravel filter frame, the gravel filter plate is connected to the side of the gravel filter frame close to the tank wall of the filter tank, and the water outlet is opened on the side of the tank wall of the filter tank connected to the gravel filter plate.

[0022] By adopting the above technical scheme, the slag removal part is connected to the filter tank through the slag filter frame, and the slag plugging piece is connected to the slag filter frame. After the sewage enters the filter tank, the slag plugging piece rotates on the slag filter frame, so that the slag in the sewage can enter under the filter frame. After the sewage in the filter tank is precipitated by gravity, the slag enters under the filter frame, and the slag plugging piece rotates to isolate the slag filter frame. After that, the water outlet is opened, and the slag filter plate covers the water outlet to isolate the slag under the filter frame, and the sewage without the slag is discharged.

[0023] Optionally, the slag filter frame includes a plurality of frame rods, each of which is connected to a rotating motor, the slag plugging member is fixedly connected to the frame rods, and the spacing between adjacent frame rods is the width of the slag plugging member.

[0024] By adopting the above technical solution, the slag filter frame is connected to the filter tank through the frame rod, and the rotating motor drives the frame rod to rotate, thereby driving the slag sealing member to rotate, and finally the slag under the filter frame is sealed.

[0025] Optionally, the slag stone plugging member includes a plugging plate, and a plurality of filter holes are formed on the plugging plate.

[0026] By adopting the above technical solution, the slag blocking member isolates the slag and stones below the filter rack through the filter holes formed in the blocking plate.

[0027] Optionally, a slag discharging mechanism is connected to the tank wall of the filter tank. The slag discharging mechanism is arranged below the slag filtering rack. The slag discharging mechanism includes a telescopic cylinder and a push plate. A slag discharging groove is formed at the end of the filter tank facing away from the telescopic cylinder, and the slag discharging groove is blocked by a blocking cover plate.

[0028] By adopting the above technical solution, after the sewage in the filter tank precipitates and stratifies and the sewage is discharged, the slag discharging mechanism starts to work. The telescopic cylinder expands and contracts to drive the push plate to move. The push plate discharges the slag and stones below the filter rack, and the slag and stones are discharged from the slag discharging groove.

[0029] A method for treating multi-stage sewage in petrochemical refining includes the following steps:

[0030] The drain valve is closed, and the floating oil removal part is in a passing state; sewage enters the interior of the filter tank from the water inlet until the interior of the filter tank is filled with sewage; the sewage is left standing until the floating oil floats to the upper part of the filter tank and the slag and stones precipitate to the bottom end of the filter tank; the floating oil removal part changes to a blocking state, the slag and stone removal part removes the slag and stones, the drain valve is opened, and the sewage separated from the floating oil and the slag and stones is discharged.

[0031] By adopting the above technical solution, under the action of gravity, the floating oil, sewage and slag and stones are separated. The floating oil removal device isolates and removes the floating oil, and the slag and stone removal part removes the slag and stones in the filter tank, realizing the stratification of the sewage and facilitating the multi-stage treatment of the sewage.

[0032] Compared with the prior art, the present application includes at least one of the following beneficial technical effects:

[0033] 1. The filter tank allows sewage to enter through the water inlet. At this time, the floating oil removal part is in a passing state and the drain valve is in a blocking state, and the filter tank is filled with sewage. Under the action of gravity, the slag and stones in the sewage precipitate at the bottom end of the filter tank, and the floating oil floats above the filter tank. At this time, the floating oil removal part changes from the passing state to the blocking state, thereby isolating the floating oil above the filter tank, and the slag and stone removal part removes the slag and stones precipitated at the bottom end of the filter tank, achieving the effect of synchronously removing the slag and stones and the floating oil in the sewage, reducing the influence of the slag and stones on the subsequent multi-stage sewage treatment device, and reducing the interference of the waste oil in the sewage on the subsequent multi-stage sewage treatment device;

[0034] 2. The floating oil removal part is positioned by the positioning frame. The deformer moves in the installation cavity, thereby changing the passing state of the floating oil removal part. When the deformer is retracted into the installation cavity, the floating oil removal part is in the passing state. When the deformer slides from the sliding guide groove to block the sewage through hole, the floating oil removal part changes to the blocking state;

[0035] 3. The floating oil discharge device is in sliding contact with the positioning frame. When sewage enters the filter tank, the floating oil discharge device is located on the tank wall of the filter tank and the discharge control valve is closed. When the floating oil removal part is in the blocking state, the discharge control valve opens, and the floating oil discharge device moves towards the direction of the discharge control valve, driving the floating oil above the positioning frame towards the discharge control valve, and then discharging the floating oil. Brief Description of the Drawings

[0036] Figure 1 is the overall structural schematic diagram of the embodiment of the present application.

[0037] Figure 2 is the schematic diagram of the opening position of the water outlet in the embodiment of the present application.

[0038] Figure 3 is the structural schematic diagram of the deformer in the embodiment of the present application.

[0039] Figure 4 is the structural schematic diagram of the sliding guide groove in the embodiment of the present application.

[0040] Figure 5 is the structural schematic diagram of the bottom end of the filter tank in the embodiment of the present application.

[0041] Figure 6 is the structural schematic diagram of the slag and stone filter rack in the embodiment of the present application.

[0042] In the figure: 1. Filter tank; 11. Water inlet; 12. Water outlet; 13. Floating oil discharge port; 14. Slag and stone discharge tank; 2. Floating oil removal part; 21. Positioning frame; 211. Installation cavity; 212. Sewage through hole; 213. Sliding guide groove; 214. Reel groove; 22. Deformer; 221. Reel motor; 222. Reel roller; 223. Deformation and blocking piece; 3. Slag and stone removal part; 31. Slag and stone filter rack; 311. Rack bar; 312. Rotating motor; 32. Slag and stone blocking member; 321. Blocking plate; 3211. Filter hole; 33. Slag and stone filter plate; 4. Drain valve; 5. Floating oil discharge device; 51. Telescopic push rod; 52. Connecting abutment plate; 53. Oil-absorbing sponge; 6. Discharge control valve; 7. Slag and stone discharge mechanism; 71. Telescopic cylinder; 72. Push plate; 8. Blocking cover plate. Detailed Embodiment

[0043] The following will further describe the present application in detail Figure 1-6 in conjunction with the attached drawings.

[0044] An embodiment of the present application discloses a multi-stage sewage treatment device and a treatment method for petrochemical refining.

[0045] Referring to Figure 1 and Figure 2 , a multi-stage sewage treatment device for petrochemical refining includes a filtration tank 1, an oil slick removal part 2, a slag and stone removal part 3, and a drain valve 4.

[0046] The filtration tank 1 is provided with a water inlet 11 and a water outlet 12. The oil slick removal part 2 is arranged on the upper part of the filtration tank 1. The oil slick removal part 2 has a blocking state and a passing state. The slag and stone removal part 3 is arranged at the bottom of the filtration tank 1. The drain valve 4 is connected to the water outlet 12 of the filtration tank 1, and the water outlet 12 communicates with a sewage collection tank (not marked in the drawings).

[0047] When the drain valve 4 is closed, the sewage generated during the petrochemical refining process enters the filtration tank 1 through the water inlet 11. At this time, the oil slick removal part 2 is in the passing state. The sewage fills the filtration tank 1 and gradually precipitates and stratifies under the action of gravity until the oil slick floats on the upper part of the filtration tank 1, and the larger slag and stones precipitate at the lower part of the filtration tank 1. At this time, the oil slick removal part 2 changes from the passing state to the blocking state, thereby isolating the oil slick on the upper part of the filtration tank 1. At the same time, the slag and stone removal part 3 removes the slag and stones at the bottom end of the filtration tank 1, and the drain valve 4 is opened, realizing the separation of the sewage into a slag and stone layer, an oil slick layer, and a water-soluble sewage layer, facilitating the multi-stage treatment of petrochemical refining sewage, reducing the influence of slag and stones on the subsequent sewage classification treatment device, and reducing the interference of waste oil in the sewage on the subsequent sewage classification treatment device.

[0048] Referring to Figure 2 and Figure 3 , the oil slick removal part 2 includes a positioning frame 21 and a deformator 22. The positioning frame 21 is fixedly connected to the tank wall of the filtration tank 1. An installation cavity 211 is formed in the positioning frame 21. The deformator 22 is arranged in the installation cavity 211. A sewage through hole 212 is formed in the middle of the positioning cavity. A sliding guide groove 213 is formed in the hole wall of the sewage through hole 212.

[0049] The oil slick removal part 2 is positioned with the tank wall of the filtration tank 1 through the positioning frame 21. The deformator 22 deforms in the installation cavity 211, so that the oil slick removal part 2 realizes the change between the passing state and the blocking state.

[0050] Referring to Figure 3 and Figure 4, the deformator 22 includes a retracting motor 221, a retracting roller 222, and a deformable sealing piece 223. The retracting motor 221 and the retracting roller 222 are evenly arranged in the installation cavity 211. The positioning frame 21 is provided with a sliding guide groove 213, and the sliding guide groove 213 is opened in the sewage through hole 212. The deformable sealing piece 223 is in sliding contact with the sliding guide groove 213, and both sides of the deformable sealing piece 223 are in sliding contact with the groove wall of the sliding guide groove 213.

[0051] The deformator 22 drives the retracting roller 222 to rotate through the retracting motor 221, thereby driving the deformable sealing piece 223 to rotate around the retracting roller 222. The retracting motor 221 makes the deformable sealing piece 223 slide in the sliding guide groove 213 through forward and reverse rotation, so that the deformable sealing piece 223 blocks the sewage through hole 212 to form a sealing state, or the deformable sealing piece 223 is retracted into the installation cavity 211 to form a passing state.

[0052] Refer to Figure 1 and Figure 2 , one side of the oil filtering tank 1 is fixedly connected with an oil floating discharging device 5. The side of the oil floating discharging device 5 facing away from the oil filtering tank 1 is in sliding contact with the positioning frame 21 and the deformable sealing piece 223. An oil floating discharge port 13 is opened on the side wall of the oil filtering tank 1 facing away from the oil floating discharging device 5. A discharge control valve 6 is connected to the oil floating discharge port 13, and the oil floating discharge port 13 communicates with an oil floating collection tank.

[0053] After the oil floating removing part 2 is in a sealing state to isolate the oil floating, the oil floating discharging device 5 works, the discharge control valve 6 is opened, and the oil floating discharging device 5 discharges the oil floating from the oil floating discharge port 13 by sliding contact with the positioning frame 21 and the deformable sealing piece 223.

[0054] Refer to Figure 1 and Figure 2 , the oil floating discharging device 5 includes a telescopic push rod 51, a connecting abutment plate 52, and an oil absorbing sponge 53. One end of the telescopic push rod 51 is fixedly connected to the groove wall of the oil filtering tank 1, the other end of the telescopic push rod 51 is fixedly connected to the connecting abutment plate 52, and the oil absorbing sponge 53 is fixedly connected to the side of the connecting abutment plate 52 facing away from the telescopic push rod 51.

[0055] When the oil floating discharging device 5 is working, through the telescopic movement of the telescopic push rod 51, the connecting abutment plate 52 is driven to move above the positioning frame 21, and the connecting bottom plate drives the oil absorbing sponge 53 to be in sliding contact with the positioning frame 21 and the deformable sealing bottom piece, so as to push the oil floating above the positioning frame 21 and the deformable sealing piece 223 towards the direction of the oil floating discharge port 13, so that the oil floating is discharged from the oil floating discharge port 13.

[0056] Refer to Figure 1 and Figure 5The slag removal part 3 includes a slag filter frame 31, a slag sealing member 32 and a slag filter plate 33. The slag filter frame 31 includes a plurality of parallel arranged frame rods 311, one end of the frame rod 311 is fixedly connected to a rotating motor 312, the filter tank 1 is provided with a plurality of rotating holes, one end of the frame rod 311 away from the rotating motor 312 is rotatably connected to the rotating hole, the slag sealing member 32 is fixedly connected to the side wall of the frame rod 311, the slag sealing member 32 can fill the gap between adjacent frame rods 311, and the slag filter plate 33 covers the water outlet 12 and is fixedly connected to the frame rod 311.

[0057] The slag removal part 3 forms a filter for blocking slag through the slag filter frame 31, the slag plugging member 32 and the slag filter plate 33, so as to isolate the slag in the lower part of the filter tank 1. The frame rod 311 is rotated by the rotary motor 312 to drive the slag plugging member 32 to rotate, so that when sewage is introduced, the slag can enter under the slag filter frame 31, and when draining, the slag plugging member 32 cooperates with the slag filter plate 33 to store the slag in the slag removal part 3.

[0058] Reference Figure 5 and Figure 6 The slag stone plugging member 32 includes a plugging plate 321 , and the plugging plate 321 is provided with a plurality of filtering holes 3211 .

[0059] The slag blocking member 32 isolates the slag in the slag removal part 3 through the filtering holes 3211 opened on the blocking plate 321, so that the sewage can enter the next treatment step through the filtering holes 3211.

[0060] Reference Figure 1 , Figure 5 and Figure 6 A slag discharge mechanism 7 is arranged under the filter frame, one side of the slag discharge mechanism 7 is fixedly connected to one side wall of the filter tank 1, a slag discharge groove 14 is opened on the groove wall of the filter tank 1 away from the slag discharge mechanism 7, and the slag discharge groove 14 is covered with a blocking cover plate 8, and one end of the slag discharge groove 14 away from the blocking cover plate 8 is connected to a slag collecting groove (not marked in the drawings), and the other side of the slag discharge mechanism 7 faces the slag discharge groove 14. When the slag discharge mechanism 7 is not working, the slag discharge groove 14 is blocked by the blocking cover plate 8. When the slag discharge mechanism 7 is working, the blocking cover plate 8 moves and the slag discharge groove 14 is opened.

[0061] When the slag discharge mechanism 7 is not working, the slag discharge mechanism 7 is covered in the slag discharge slot 14 by the blocking cover plate 8. When the slag discharge mechanism 7 is working, the slag discharge mechanism 7 moves in the direction of the slag discharge slot 14 to discharge the slag from the slag discharge slot 14.

[0062] Reference Figure 1 and Figure 5, the slag discharging mechanism 7 includes a telescopic cylinder 71 and a push plate 72. One end of the telescopic cylinder 71 is fixedly connected to one side of the filter tank 1, and the other end of the telescopic cylinder 71 is arranged towards the slag discharging groove 14 and fixedly connected to the push plate 72. The bottom end of the connecting push plate 72 is in sliding contact with the bottom of the filter tank 1, and the top end of the connecting push plate 72 is in sliding contact with the bottom end of the support rod 311.

[0063] The telescopic cylinder 71 drives the push plate 72 to move towards the slag discharging groove 14. The push plate 72 removes the slag between the support rod 311 and the bottom of the filter tank 1 by contacting with the bottom of the filter tank 1 and the support rod 311.

[0064] The implementation principle of a petrochemical refining multi-stage sewage treatment device in an embodiment of the present application is as follows: The drain valve 4 in the filter tank 1 is closed, and the sewage from petrochemical refining enters through the water inlet 11. The floating oil removal part 2 allows the sewage to enter the inside of the filter tank 1 in a passing state. Under the action of gravity, the floating oil in the sewage floats up, and the slag and stone particles sink, forming a floating oil layer suspended in the upper part of the filter tank 1, a slag and stone layer in the lower part of the filter tank 1, and a sewage layer in the middle of the filter tank 1. At this time, the floating oil removal part 2 changes to a blocking state to isolate the floating oil layer. The slag removal part 3 processes the slag and stones in the slag and stone layer. The drain valve 4 is opened, and the sewage layer in the middle is discharged from the water outlet 12 and enters the next processing step, realizing the classification of sewage, facilitating the multi-stage treatment of petrochemical refining sewage, reducing the impact of slag and stones on the subsequent sewage classification treatment device, and reducing the interference of waste oil in the sewage on the subsequent sewage classification treatment device.

[0065] A treatment method for petrochemical refining multi-stage sewage treatment includes the following steps:

[0066] The drain valve 4 is closed, and the floating oil removal part 2 is in a passing state; the sewage enters the inside of the filter tank 1 from the water inlet 11 until the inside of the filter tank 1 is filled with sewage; the sewage is left standing until the floating oil floats to the upper part of the filter tank 1 and the slag and stones precipitate to the bottom of the filter tank 1; the floating oil removal part 2 changes to a blocking state, the slag removal part 3 removes the slag and stones, and the drain valve 4 is opened to discharge the sewage after separating the floating oil and the slag and stones.

[0067] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited by this. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A multi-stage sewage treatment device for petrochemical refining, characterized in that, include: A filter tank (1) is provided with a water inlet (11) and a water outlet (12); The floating oil removal part (2) is located in the filter tank (1) and arranged on the upper part of the filter tank (1). The floating oil removal part (2) has a blocking state and a passable state. When the floating oil removal part (2) is in the blocking state, the floating oil removal part (2) blocks the upper part of the filter tank (1). When the floating oil removal part (2) is in the passable state, the floating oil removal part (2) allows the refinery wastewater to pass through. The floating oil removal part (2) comprises a positioning frame (21) and a deformer (22). The positioning frame (21) is fixedly connected to the tank wall of the filter tank (1). The positioning frame (21) is provided with an installation cavity (211) inside. The deformer (22) is arranged in the installation cavity (211), a plurality of sewage through holes (212) are opened in the middle of the positioning frame (21), a sliding guide groove (213) is opened on the hole wall of the sewage through hole (212), and the deformer (22) is slidably connected to the sliding guide groove (213); the deformer (22) comprises a winding motor (221), a winding roller (222) and a deformation blocking piece (223), the winding motor (221) and the winding roller (222) are both arranged in the installation cavity (211), and the positioning frame (21) is opened to connect the sliding guide groove (213), the installation cavity (211) and the sewage through hole (212). The retracting groove (214) of the water through hole (212) is provided with a retracting groove (214), and the two ends of the deformable sealing piece (223) are in sliding contact with the groove wall of the retracting groove (214), and the two sides of the deformable sealing piece (223) are in sliding contact with the groove wall of the sliding guide groove (213); a groove wall on one side of the filter groove (1) is connected with a floating oil discharge device (5), and the floating oil discharge device (5) is arranged above the positioning frame (21), and the floating oil discharge device (5) is used for sliding contact with the positioning frame (21) and the deformable sealing piece (223); a floating oil discharge outlet (131) is provided on the groove wall of the filter groove (1) on the side away from the floating oil discharge device (5) ), the floating oil discharge port (13) is connected to a discharge control valve (6); the floating oil discharge device (5) comprises a telescopic push rod (51), a connecting plate (52) and an oil absorbing sponge (53); one end of the telescopic push rod (51) is connected to one side of the filter tank (1); the connecting plate (52) is fixedly connected to the other end of the telescopic push rod (51); a gap at the bottom end of the connecting plate (52) is arranged above the positioning frame (21); the oil absorbing sponge (53) is connected to a side of the connecting plate (52) away from the telescopic push rod (51); and the oil absorbing sponge (53) is used to slidably abut against the deformation blocking piece (223); The slag and stone removal part (3) is arranged at the bottom of the filtering tank (1) and is arranged at an interval from the bottom end of the filtering tank (1). The slag and stone removal part (3) is used for removing slag and stones in the sewage in the filtering tank (1). The slag and stone removal part (3) includes a slag and stone filtering frame (31), a slag and stone blocking part (32) and a slag and stone filtering plate (33). The slag and stone filtering frame (31) is connected to the tank wall of the filtering tank (1). The slag and stone blocking part (32) is rotatably connected to the slag and stone filtering frame (31). The slag and stone filtering plate (33) is connected to one side of the slag and stone filtering frame (31) close to the tank wall of the filtering tank (1). The water outlet (12) is opened on the tank wall of the filtering tank (1) connecting the slag and stone filtering plate (33). The drain valve (4) is connected to the water outlet (12) of the filtering tank (1) and is used for discharging the filtered sewage.

2. The petrochemical refining multi-stage sewage treatment device according to claim 1, characterized in that: The slag and stone filtering frame (31) includes a plurality of frame rods (311). A rotating motor (312) is connected to each of the frame rods (311). The slag and stone blocking part (32) is fixedly connected to the frame rods (311). The distance between adjacent frame rods (311) is the width of the slag and stone blocking part (32).

3. A petrochemical refinery multi-stage sewage treatment device according to claim 1, characterized in that: The slag and stone blocking part (32) includes a blocking plate (321). A plurality of filtering holes (3211) are opened on the blocking plate (321).

4. A petrochemical refining multi-stage sewage treatment device according to claim 1, characterized in that: A slag and stone discharging mechanism (7) is connected to the tank wall of the filtering tank (1). The slag and stone discharging mechanism (7) is arranged below the slag and stone filtering frame (31). The slag and stone discharging mechanism (7) includes a telescopic cylinder (71) and a push plate (72). A slag and stone discharging groove (14) is opened at the end of the filtering tank (1) facing away from the telescopic cylinder (71). The slag and stone discharging groove (14) is blocked by a blocking cover plate (8).

5. A method for treating multi-stage petrochemical refinery sewage, which is applied to the petrochemical refinery multi-stage sewage treatment device described in any one of claims 1-4, and includes the following steps: When the drain valve (4) is closed, the floating oil removal part (2) is in a passing state. Sewage enters the inside of the filtering tank (1) from the water inlet (11) until the inside of the filtering tank (1) is filled with sewage. The sewage is left standing until the floating oil floats to the upper part of the filtering tank (1) and the slag and stones precipitate to the bottom end of the filtering tank (1). The floating oil removal part (2) changes to a blocking state. The slag and stone removal part (3) removes the slag and stones. The drain valve (4) is opened to discharge the sewage after separating the floating oil and the slag and stones.

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