A gas float device for oil and gas field sewage treatment

Abstract

The present application belongs to the technical field of oil and gas field sewage treatment, and specifically discloses a gas floatation device for oil and gas field sewage treatment, which comprises a gas floatation tank, a suspended matter absorber and a filter tank, the suspended matter absorber is fixedly installed near the tank wall of the gas floatation tank, a plurality of cavities are arranged in the suspended matter absorber, a through hole is arranged on the bottom end surface of a piston, and an absorption hole is arranged on the side surface of the absorber at the bottom end position of each cavity; the filter tank is arranged near the top position in the gas floatation tank, a filter assembly is arranged in the filter tank, the filter assembly is composed of a rotating shaft, two groups of filter screens and two groups of partition plates connected to the rotating shaft, and two groups of end plates at the two ends of the rotating shaft; and an inclined disc is further arranged on the top of the gas floatation tank. The present application can treat floating sludge through the filter tank, realize the separation and treatment of oil and solid pollutants, reduce the processing cost of subsequent oil recycling, absorb and remove suspended matters through the absorber, and greatly reduce the content of suspended pollutants in the discharged water.

Description

Technical Field

[0001] This invention relates to the technical field of oil and gas field wastewater treatment, specifically to an air flotation device for oil and gas field wastewater treatment. Background Technology

[0002] Oil and gas field production water contains a significant amount of floating oil, suspended oil, particulate matter, organic matter, heavy metals, and other pollutants, requiring treatment to meet discharge standards. Physical methods such as gravity and flotation are commonly used for pretreatment of oil and gas field wastewater, removing most suspended solids and oil. Subsequent biochemical methods, such as microbial degradation, further remove other pollutants.

[0003] Air flotation (AF) devices are the main equipment for flotation. They use microbubbles to adsorb and bind with suspended oil droplets and flocs, causing them to float to the surface and form scum. This scum is then removed by skimming, achieving separation of water and scum. However, the scum contains not only oil but also a large amount of light solids formed by the aggregation of flocs and hydrolysis products of inorganic coagulants. Skimming removes oil and other impurities along with the scum, resulting in high levels of oil, impurities, and pollutants in the recovered wastewater. This makes it difficult to recycle or requires further purification, hindering economic efficiency. Furthermore, some solid impurities and heavier aggregates cannot generate sufficient buoyancy to float to the surface due to limited bubble adhesion, remaining suspended in the water. Existing AF devices are ineffective at removing these impurities, resulting in still high pollutant levels in the discharged wastewater after flotation. Summary of the Invention

[0004] The purpose of this invention is to provide an air flotation device for treating oil and gas field wastewater, so as to solve the problems mentioned in the background art that existing air flotation devices cannot separate and treat scum from oil and gas field wastewater and cannot remove suspended solids in water by flotation.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A flotation device for treating oil and gas field wastewater includes: a flotation tank, a suspended solids absorber, and a filter tank. A drive device is installed on the top of the flotation tank, and the drive device is connected to a drive shaft. A pulsator is connected to the bottom end of the drive shaft. The pulsator is located at the bottom of the flotation tank and is rotatably connected to the flotation tank. A micro-nano bubble generator is installed at the bottom of the flotation tank below the pulsator.

[0007] The suspended solids absorber is a vertical tubular structure. It is fixedly installed near the wall of the flotation tank. The suspended solids absorber has multiple cavities inside, which are separated by pipe plugs. A piston is installed in each cavity, and the pistons in adjacent cavities are connected by pipes. The pipes and pistons are all connected. The bottom end of the piston has a through hole. The side of the suspended solids absorber has an absorption hole at the bottom of each cavity.

[0008] The filter tank is located near the top of the air flotation tank. The filter tank is a horizontal tubular structure with a through groove on its top surface. A filter assembly is installed inside the filter tank. The filter assembly consists of a rotating shaft, two sets of filter screens and two sets of baffles connected to the rotating shaft, and two sets of end panels at both ends of the rotating shaft. The two sets of end panels are fixed to both ends of the filter tank. The rotating shaft is rotatably connected to the end panels. The two sets of filter screens and two sets of baffles are arranged alternately and perpendicularly to each other.

[0009] The top of the air flotation tank is also provided with a swashplate, which is rotatably connected to the air flotation tank. A connecting rod is movably connected to the bottom of the swashplate. The connecting rod is connected to a connector located at the top of the suspended solids absorber. The connector is connected to the uppermost piston. The connecting rod is provided with a rack structure at the position of the gear mechanism.

[0010] As a further aspect of the present invention: a floating retaining ring is provided inside the piston above the through hole.

[0011] As a further aspect of the present invention: a sleeve is provided between the piston and the suspended matter absorber, and a hollow groove is provided on the side of the sleeve. The hollow groove is composed of two longitudinal grooves and two helical grooves, which are connected end to end in sequence.

[0012] As a further aspect of the present invention: a valve hole is provided on the side of the bottom end of the sleeve at the position corresponding to the absorption hole.

[0013] As a further aspect of the present invention: a separator cylinder is connected between the filter screen and the partition.

[0014] As a further aspect of the present invention: the filter tank is also connected to an oil baffle on one side of the through channel.

[0015] As a further aspect of the present invention: the suspended matter absorber, the filter tank and the connecting rod are all arranged in an array of multiple units.

[0016] As a further aspect of the present invention: one end of the filter tank is provided with a connection port, the connection port is connected to the water outlet through a pipe, the water outlet is located on the top side of the suspended solids absorber, and the filter assembly is provided with a water passage hole on the end panel located at this end.

[0017] As a further embodiment of the present invention: the filter tank is provided with a gear mechanism at one end of the opposite connection port, the gear mechanism is connected to the rotating shaft, the filter assembly is provided with a suspended solids outlet at the bottom of this end, the suspended solids outlet is connected to a suspended solids discharge pipe, and the filter assembly is provided with an oil outlet on the end panel located at this end, the oil outlet is connected to an oil discharge pipe.

[0018] As a further aspect of the present invention: there is rotational damping between the rotating shaft and the end panel.

[0019] Compared with the prior art, the beneficial effects of the present invention are: 1. The flotation tank of the present invention is used to treat oily wastewater from oil and gas fields. The scum is treated by the filter tank to achieve the separation of oil and solid pollutants, thereby reducing the processing cost of subsequent oil recycling.

[0020] 2. This invention targets suspended pollutants that are suspended in water and cannot float. It first collects the suspended matter through swirling centrifugal force, and then absorbs and removes the suspended matter through an absorber, thereby greatly reducing the content of suspended pollutants in the discharged water. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the internal structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the cross-sectional structure of the end face of the present invention.

[0023] Figure 3 This is a schematic diagram of the suspended matter absorber in this invention.

[0024] Figure 4 This is a schematic diagram of the sleeve structure in this invention.

[0025] Figure 5 This is a schematic diagram of the top surface structure of the filter tank in this invention.

[0026] Figure 6 This is a schematic diagram of the end face cross-sectional structure of the filter tank in this invention.

[0027] In the diagram, 1. Flotation tank; 11. Drive unit; 12. Swashplate; 13. Drive shaft; 14. Connecting rod; 141. Rack structure; 15. Impeller; 16. Micro / nano bubble generator; 17. Sewage pump; 2. Suspended solids absorber; 21. Outlet; 211. Pipe; 22. Cavity; 221. Piston; 2211. Retaining ring; 222. Tube; 223. Absorption hole; 224. Sleeve; 2241. Longitudinal groove; 2242. Spiral groove; 2243. Valve hole; 23. Connector; 24. Pipe plug; 3. Filter tank; 31. Oil discharge pipe; 311. Oil outlet; 32. Suspended solids discharge pipe; 321. Suspended solids outlet; 33. Connection port; 331. Water passage hole; 34. Baffle; 35. Filter screen; 36. Rotating shaft; 37. Gear mechanism; 38. Oil baffle; 39. Separator cylinder. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please see Figure 1 In this embodiment of the invention, an air flotation device for treating oil and gas field wastewater includes: an air flotation tank 1, a suspended solids absorber 2, and a filter tank 3. A drive device 11 is installed on the top of the air flotation tank 1. The drive device 11 is connected to a drive shaft 13. A pulsator 15 is connected to the bottom of the drive shaft 13. The pulsator 15 is located at the bottom of the air flotation tank 1 and is rotatably connected to the air flotation tank 1. A micro-nano bubble generator 16 is also provided at the bottom of the air flotation tank 1 below the pulsator 15 for injecting a large number of microbubbles into the wastewater at the bottom of the tank.

[0030] like Figure 2 , 3The suspended solids absorber 2 is a vertical tubular structure, fixedly installed near the wall of the flotation tank 1. Multiple cavities 22 are provided inside the suspended solids absorber 2, with adjacent cavities 22 separated by pipe plugs 24. A piston 221 is installed inside each cavity 22, and pistons 221 in adjacent cavities 22 are connected by pipes 222, with the pipes 222 communicating with the interior of each piston 221. A through hole is provided on the bottom surface of the piston 221, and a floating retaining ring 2211 is provided above the through hole inside the piston 221. Absorption holes 223 are provided on the side of the suspended solids absorber 2 at the bottom of each cavity 22. A sleeve 224 is also provided between the piston 221 and the suspended solids absorber 2. The side of the sleeve 224 has a perforated groove, consisting of two longitudinal grooves 2241 and two helical grooves 2241. Composed of 242, the sleeve 224 consists of two longitudinal grooves 2241 and two spiral grooves 2242 connected end to end. A protrusion embedded in a hollow groove is provided at the edge of the piston 221. When the piston 221 moves up and down, the sleeve 224 moves through the hollow groove. Specifically, when the protrusion moves with the piston 221 within the longitudinal groove 2241, the sleeve 224 does not move. When the protrusion moves to the end position of the spiral groove 2242 and continues to move, it will generate a rotational force on the sleeve 224, causing the sleeve 224 to rotate. During the cyclical movement of the protrusion within the hollow groove, the two spiral grooves 2242 cause the sleeve 224 to rotate in opposite directions. A valve hole 2243 is also provided on the bottom side of the sleeve 224 corresponding to the absorption hole 223. As the sleeve 224 rotates, the valve hole 2243 overlaps with and intersects with the absorption hole 223, thus opening and closing the absorption hole 223.

[0031] like Figure 4 , 5The filter tank 3 is located near the top of the flotation tank 1. The filter tank 3 is a horizontal tubular structure with a through groove on its top surface. A filter assembly is installed inside. The filter assembly consists of a rotating shaft 36, two sets of filter screens 35 and two sets of partitions 34 connected to the rotating shaft 36, and two sets of end panels at both ends of the rotating shaft 36. The two sets of end panels are fixed to both ends of the filter tank 3. The rotating shaft 36 is rotatably connected to the end panels and has rotational damping. The two sets of filter screens 35 and two sets of partitions 34 are arranged alternately and perpendicularly. A separator cylinder 39 connects the filter screens 35 and the partitions 34. One end of the filter tank 3 has a connection port 33, which is connected to the outlet 21 via a pipe 211. 21 is set on the top side of the suspended solids absorber 2. The filter assembly has a water passage hole 331 on the end panel at this end. The water passage hole 331 is used to connect the connection port 33 and the inside of the filter assembly. The other end of the filter tank 3 is provided with a gear mechanism 37, which is connected to the rotating shaft 36. The bottom of the filter assembly at this end is provided with a suspended solids outlet 321, which is connected to a suspended solids discharge pipe 32. The filter assembly has an oil outlet hole 311 on the end panel at this end, which is connected to an oil discharge pipe 31. The filter tank 3 is also connected to an oil baffle 38 on one side of the through groove. The oil baffle 38 is higher than the oil surface so that the oil layer on this side cannot flow into the through groove.

[0032] The suspended solids absorber 2 and the filter tank 3 are arranged in an array of multiple units. An inclined plate 12 is also provided at the top of the air flotation tank 1. The inclined plate 12 is rotatably connected to the air flotation tank 1. Multiple connecting rods 14 are movably connected to the bottom of the inclined plate 12. The connecting rods 14 are respectively connected to the connectors 23 located at the top of the suspended solids absorber 2. The connectors 23 are connected to the uppermost piston 221. The connecting rods 14 are provided with rack structures 141 at the position of the gear mechanism 37. After the rack structure 141 meshes with the gear, it drives the rotation of the rotating shaft 36, i.e., the filter assembly.

[0033] A sewage pump 17 is connected to the bottom of the flotation tank 1. Sewage is injected into the tank from the bottom through the sewage pump 17. After the sewage injection reaches the working height, the injection stops. A large number of microbubbles are injected into the sewage pump through the micro-nano bubble generator 16. The microbubbles adhere to the suspended oil droplets, flocculents, etc. in the sewage and bring them to the surface. At the same time, the drive device 11 drives the impeller 15 to rotate at a low speed through the drive shaft 13, so that the sewage in the tank forms a swirling flow. Under the action of centrifugal force of the swirling flow, some of the larger suspended solids that cannot float are dispersed to a position close to the tank wall. The drive shaft 13 drives the swashplate 12 to rotate synchronously. When the swashplate 12 rotates, the height position of the connecting rod 14 changes, forming a reciprocating motion. Assuming that the connecting rod 14 starts to move upward from the lowest stroke position, the piston 221 is driven to move upward during the upward movement. At this time, the floating retaining ring 2211 inside the piston 221 presses against the through hole on the bottom end face of the piston 221 due to the negative pressure. The piston 221 draws the water near the outside of the suspended solids absorber 2 into the air. Inside cavity 22, during this process, the protrusion moves within the longitudinal groove 2241. When piston 221 moves close to its maximum stroke position, the protrusion enters the spiral groove 2242. As it continues to move upward, sleeve 224 rotates until it closes the bottom absorption hole 223. At this point, piston 221 reaches its maximum stroke position and begins to move downward. During the above process, due to the centrifugal separation, the suspended solids content in the water at this position is relatively high. Therefore, most of the pollutants suspended in the water can be removed in this step. After piston 221 reaches its maximum stroke position, it begins to move downward. At this point, the protrusion enters another longitudinal groove 2241 and does not affect sleeve 224. When piston 221 moves downward, it pressurizes the sewage in cavity 22. At this point, the sewage can only enter from the through hole on the bottom end face of piston 221. The sewage in the lower piston 221 will be transported upward through connecting pipe 222, and finally the sewage will be pressed into outlet 21 and sent to connection port 33 through pipe 211. By repeating the cycle, suspended pollutants in the sewage can be removed.

[0034] Smaller suspended pollutants, carried by microbubbles, form a scum layer on the water surface. Under the influence of swirling current, this scum layer converges towards the filter tank 3 on one side and enters the filter assembly through the opening of the channel. The scum is filtered through the filter screen 35, leaving solids. Oil flows from the filter screen 35 downwards, collects, and is discharged outside the tank through the oil outlet 311. By designing the relevant parameters of the rack and pinion meshing transmission, the connecting rod 14 causes the gear to rotate half a revolution in one stroke, meaning the filter assembly is in a reciprocating 180° rotational motion. When the upper... When the filter screen 35 rotates into the filter tank 3, the separator cylinder 39 begins to rotate out and gradually closes the opening of the through groove, while the filter screen 35 at the bottom begins to rotate to the top, realizing the switching of the filter screen 35. After the filter screen 35 enters the bottom, the sewage containing suspended solids that is pressed into the connection port 33 flows through the water passage 331 to the other side at the bottom of the filter assembly. During the flow, it comes into contact with the filter screen 35 and washes down the suspended solids filtered down by the filter screen 35, and discharges them out of the tank from the suspended solids outlet 321, thereby realizing the separation of oil and solid slag in the scum.

[0035] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0036] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A flotation device for treating oil and gas field wastewater, comprising: The air flotation tank (1), the suspended solids absorber (2) and the filter tank (3) are provided. A drive device (11) is installed on the top of the air flotation tank (1). The drive device (11) is connected to a drive shaft (13). A pulsator (15) is connected to the bottom of the drive shaft (13). The pulsator (15) is located at the bottom of the air flotation tank (1) and is rotatably connected to the air flotation tank (1). A micro-nano bubble generator (16) is provided at the bottom of the air flotation tank (1) below the pulsator (15). The feature is that the suspended matter absorber (2) is a vertical tube structure. The suspended matter absorber (2) is fixedly installed near the tank wall of the air flotation tank (1). The suspended matter absorber (2) is provided with multiple cavities (22). Adjacent cavities (22) are separated by pipe plugs (24). A piston (221) is provided in the cavity (22). The pistons (221) in adjacent cavities (22) are connected by pipes (222). The pipes (222) and the pistons (221) are all connected. The bottom end face of the piston (221) is provided with a through hole. The side of the suspended matter absorber (2) is provided with an absorption hole (223) at the bottom end of each cavity (22). The filter tank (3) is located near the top of the air flotation tank (1). The filter tank (3) is a horizontal tube structure with a through groove on its top surface and a filter assembly inside. The filter assembly consists of a rotating shaft (36), two sets of filter screens (35) and two sets of partitions (34) connected to the rotating shaft (36) respectively, and two sets of end panels at both ends of the rotating shaft (36). The two sets of end panels are fixed to both ends of the filter tank (3). The rotating shaft (36) is rotatably connected to the end panels. The two sets of filter screens (35) and the two sets of partitions (34) are arranged alternately and perpendicular to each other. The air flotation tank (1) is also provided with a swash plate (12) at the top. The swash plate (12) is rotatably connected to the air flotation tank (1). A connecting rod (14) is movably connected to the bottom end of the swash plate (12). The connecting rod (14) is connected to the connector (23) at the top of the suspended solids absorber (2). The connector (23) is connected to the uppermost piston (221). The connecting rod (14) is provided with a rack structure (141) at the position of the gear mechanism (37). A floating retaining ring (2211) is provided inside the piston (221) above the through hole. A sleeve (224) is provided between the piston (221) and the suspended matter absorber (2). A hollow groove is provided on the side of the sleeve (224). The hollow groove is composed of two longitudinal grooves (2241) and two spiral grooves (2242). The two longitudinal grooves (2241) and the two spiral grooves (2242) are connected end to end in sequence. A valve hole (2243) is provided on the side of the bottom end of the sleeve (224) at the position corresponding to the absorption hole (223). One end of the filter tank (3) is provided with a connection port (33), which is connected to the outlet (21) through a pipe (211). The outlet (21) is located on the top side of the suspended solids absorber (2), and the filter assembly is provided with a water passage hole (331) on the end panel located at this end. The filter tank (3) is provided with a gear mechanism (37) at one end relative to the connection port (33). The gear mechanism (37) is connected to the rotating shaft (36). The filter assembly is provided with a suspended matter outlet (321) at the bottom of this end. The suspended matter outlet (321) is connected to a suspended matter discharge pipe (32). The filter assembly is provided with an oil outlet (311) on the end panel located at this end. The oil outlet (311) is connected to an oil discharge pipe (31).

2. The air flotation device for treating oil and gas field wastewater according to claim 1, characterized in that: A separator cylinder (39) is connected between the filter screen (35) and the partition plate (34).

3. The air flotation device for treating oil and gas field wastewater according to claim 1 or 2, characterized in that: The filter tank (3) is located on one side of the through channel and is connected to an oil baffle (38).

4. The air flotation device for treating oil and gas field wastewater according to claim 1, characterized in that: The suspended matter absorber (2), filter tank (3) and connecting rod (14) are arranged in an array of multiple units.

5. The air flotation device for treating oil and gas field wastewater according to claim 1, characterized in that: The rotating shaft (36) has rotational damping between itself and the end panel.

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