Air floatation device for oil and gas field sewage treatment

Abstract

The invention belongs to the related technical field of oil and gas field sewage treatment, and particularly discloses an oil and gas field sewage treatment air flotation device which comprises an air flotation tank, a suspended matter absorber and a filter tank, the suspended matter absorber is fixedly installed at the position close to the tank wall of the air flotation tank, a plurality of cavities are formed in the suspended matter absorber, and a through hole is formed in the bottom end face of a piston. An absorption hole is formed in the side surface of the floating object absorber and is positioned at the bottom end of each cavity; the filter tank is arranged close to the top in the air floatation tank, a filter assembly is arranged in the filter tank, and the filter assembly is composed of a rotating shaft, two groups of filter screens and two groups of partition plates respectively connected to the rotating shaft, and two groups of end panels at two ends of the rotating shaft; and a swash plate is also arranged at the top in the air floatation tank. According to the invention, scum is treated through the filter tank, so that separation treatment of oil and solid pollutants is realized, and the processing cost of subsequent recycling of oil is reduced; suspended matters are absorbed and discharged through the absorber, so that the content of suspended pollutants in discharged water is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field related to oil and gas field sewage treatment, in particular to an air flotation device for oil and gas field sewage treatment. Background Art

[0002] The produced water of oil and gas fields contains a lot of floating oil, suspended oil, solid particles, organic matter, heavy metals and other pollutants, which need to be treated to meet the discharge standards. Physical methods such as gravity and flotation are common methods for pre-treatment of oil and gas field wastewater, which can remove most of the suspended matter and oil in the wastewater, and then biochemical methods such as microbial degradation can be used to further remove other pollutants.

[0003] The flotation device is the main equipment for flotation. The generated microbubbles are adsorbed and combined with suspended oil droplets, flocculants, etc., and then float to the surface to form scum. The scum is removed by scraping, and the separation of water and scum is achieved. The scum contains not only oil, but also a large amount of light solids formed by the aggregation of flocculants and hydrolysis products of inorganic coagulants. The oil and other impurities are discharged together by scraping, resulting in a high content of impurities and pollutants in the recovered oil, which is not easy to recycle or needs further purification and treatment, which is not conducive to the economic benefits of recycling; in addition, some solid impurities and heavy impurities are unable to generate enough buoyancy to float to the surface due to the limited adhesion of bubbles, and continue to float freely in the water. The existing flotation device is not effective in removing these impurities, resulting in a high content of pollutants in the sewage discharged after flotation. Summary of the invention

[0004] The object of the present invention is to provide an air flotation device for treating oil and gas field wastewater to solve the problem that the existing air flotation device mentioned in the background art cannot separate and treat the scum of oil and gas field wastewater and cannot float and remove suspended matter in the water.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An air flotation device for treating wastewater in oil and gas fields, comprising: an air flotation tank, a suspended matter absorber and a filter tank, wherein a driving device is installed on the top of the air flotation tank, the driving device is connected to a driving shaft, the bottom end of the driving shaft is connected to a pulsator, the pulsator is located at the bottom of the air flotation tank and is rotatably connected to the air flotation tank, and a micro-nano bubble generating device is arranged at the bottom of the air flotation tank below the pulsator;

[0007] The suspended matter absorber is a vertical tube structure, and the suspended matter absorber is fixedly installed near the wall of the flotation tank. A plurality of cavities are arranged in the suspended matter absorber, and adjacent cavities are separated by pipe plugs. Pistons are arranged in the cavities, and the pistons in adjacent cavities are connected by pipes, and the pipes are connected to the inside of the pistons. A through hole is arranged on the bottom end surface of the piston, and an absorption hole is arranged on the side of the suspended matter absorber at the bottom end of each cavity;

[0008] The filter tank is arranged near the top of the flotation tank. The filter tank is a horizontal tube structure with a through groove on the top surface. A filter assembly is arranged inside the filter tank. The filter assembly is composed of a rotating shaft, two groups of filter screens and two groups of partitions respectively connected to the rotating shaft, and two groups of end panels at both ends of the rotating shaft. The two groups of end panels are respectively fixed at the two ends of the filter tank. The rotating shaft is rotatably connected to the end panels. The two groups of filter screens and the two groups of partitions are alternately arranged in sequence and are perpendicular to each other.

[0009] A swash plate is also provided at the top of the flotation tank, and the swash plate is rotatably connected to the flotation tank. A connecting rod is movably connected to the bottom of the swash plate, and the connecting rod is connected to a connecting head at the top of the suspended matter absorber, and the connecting head is connected to the uppermost piston; a rack structure is provided at the connecting rod at the position of the gear mechanism.

[0010] As a further solution of the present invention: a floating retaining ring is arranged in the piston above the through hole.

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

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

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

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

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

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

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

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

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

[0020] 2. The present invention aims at the suspended pollutants suspended in the water but unable to float up. The suspended matter is first collected by cyclonic centrifugal action and then absorbed and removed by the absorber, thereby greatly reducing the content of suspended pollutants in the discharged water. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0023] Figure 3 It is a schematic diagram of the structure of the suspended matter absorber in the present invention.

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

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

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

[0027] In the figure, 1, flotation tank; 11, driving device; 12, inclined plate; 13, driving shaft; 14, connecting rod; 141, rack structure; 15, impeller; 16, micro-nano bubble generating device; 17, sewage pump; 2, suspended matter absorber; 21, water outlet; 211, pipeline; 22, cavity; 221, piston; 2211, retaining ring; 222, pipe; 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 matter discharge pipe; 321, suspended matter outlet; 33, connecting port; 331, water hole; 34, partition; 35, filter screen; 36, rotating shaft; 37, gear mechanism; 38, oil baffle; 39, separation cylinder. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] See also Figure 1 In an embodiment of the present invention, a flotation device for treating oil and gas field wastewater comprises: a flotation tank 1, a suspended matter absorber 2 and a filter tank 3, a driving device 11 is installed on the top of the flotation tank 1, the driving device 11 is connected to a driving shaft 13, a pulsator 15 is connected to the bottom of the driving shaft 13, the pulsator 15 is located at the bottom of the flotation tank 1, and is rotatably connected to the flotation tank 1, and a micro-nano bubble generating device 16 is also arranged at the bottom of the flotation tank 1 below the pulsator 15, which is used to inject a large number of micro-bubbles into the wastewater at the bottom of the tank;

[0030] like Figure 2 , 3The suspended matter absorber 2 is a vertical tube structure, and the suspended matter absorber 2 is fixedly installed near the tank wall of the flotation tank 1. A plurality of cavities 22 are arranged in the suspended matter absorber 2, and adjacent cavities 22 are separated by pipe plugs 24. A piston 221 is arranged in the cavity 22, and the pistons 221 in adjacent cavities 22 are connected by pipes 222, and the pipes 222 are connected to the inside of the pistons 221. A through hole is arranged on the bottom end surface of the piston 221, and a floating retaining ring 2211 is arranged above the through hole in the piston 221. An absorption hole 223 is arranged on the side of the suspended matter absorber 2 at the bottom end position of each cavity 22; a sleeve 224 is also arranged between the piston 221 and the suspended matter absorber 2, and a hollow groove is arranged on the side of the sleeve 224, and the hollow groove consists of two sections of longitudinal longitudinal grooves 2241 and two sections of spiral grooves 2241 in a spiral direction. 242, two sections of longitudinal grooves 2241 and two sections of spiral grooves 2242 are connected end to end in sequence, and a protrusion embedded in the hollow groove is provided at the edge of the piston 221. When the piston 221 moves up and down, the sleeve 224 can move through the hollow groove. Specifically, when the protrusion moves with the piston 221 in 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 to rotate the sleeve 224. During the circular movement of the protrusion in the hollow groove, the two sections of spiral grooves 2242 cause the sleeve 224 to rotate in opposite directions respectively; a valve hole 2243 is also provided on the side surface of the bottom end of the sleeve 224 at a position corresponding to the absorption hole 223. During the rotation of the sleeve 224, the valve hole 2243 overlaps and interlaces with the absorption hole 223 to open and close the absorption hole 223;

[0031] like Figure 4 , 5The filter tank 3 is arranged near the top of the flotation tank 1. The filter tank 3 is a horizontal tube structure with a through groove on its top surface. A filter assembly is arranged inside the filter tank 3. The filter assembly consists of a rotating shaft 36, two groups of filter screens 35 and two groups of partitions 34 respectively connected to the rotating shaft 36, and two groups of end panels at both ends of the rotating shaft 36. The two groups of end panels are respectively fixed to the two ends of the filter tank 3. The rotating shaft 36 is rotatably connected to the end panels and has rotation damping. The two groups of filter screens 35 and the two groups of partitions 34 are alternately arranged in sequence and are perpendicular to each other. A separation cylinder 39 is also connected between the filter screens 35 and the partitions 34. A connecting port 33 is provided at one end of the filter tank 3. The connecting port 33 is connected to the water outlet 21 through a pipe 211. The water outlet 21 is arranged on the top side of the suspended matter absorber 2, and the filter component is provided with a water hole 331 on the end panel located at this end, and the water hole 331 is used to connect the connecting port 33 and the inside of the filter component; the other end of the filter tank 3 is provided with a gear mechanism 37, and the gear mechanism 37 is connected to the rotating shaft 36. The filter component is provided with a suspended matter outlet 321 at the bottom of this end, and the suspended matter outlet 321 is connected to the suspended matter discharge pipe 32, and the filter component is provided with an oil outlet hole 311 on the end panel located at this end, and the oil outlet hole 311 is connected to the oil discharge pipe 31; the filter tank 3 is also connected to an oil baffle 38 on one side of the through groove, and the height of 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 matter absorber 2 and the filter tank 3 are arranged in multiple arrays. A swash plate 12 is also provided at the top of the flotation tank 1. The swash plate 12 is rotatably connected to the flotation tank 1. A plurality of connecting rods 14 are movably connected to the bottom of the swash plate 12. The connecting rods 14 are respectively connected to the connectors 23 located at the top of the suspended matter absorber 2. The connectors 23 are connected to the piston 221 at the top. The connecting rods 14 are provided with a rack structure 141 at the position of the gear mechanism 37. The rack structure 141 drives the rotation of the rotating shaft 36, i.e., the filter assembly, after being meshed with the gear.

[0033] A sewage pump 17 is connected to the bottom of the flotation tank 1. Sewage is injected into the tank from the bottom of the flotation tank 1 through the sewage pump 17. When the sewage injection height reaches the operating height, the water injection is stopped. A large number of microbubbles are injected into the sewage pump through the micro-nano bubble generating device 16. The microbubbles adhere to the oil droplets and flocculants suspended in the sewage and bring them to the surface. At the same time, the driving device 11 drives the impeller 15 to rotate at a low speed through the driving shaft 13, so that the sewage in the tank forms a vortex. Under the action of the centrifugal force of the vortex, some suspended matter with a large mass that cannot float is dispersed to a position close to the tank wall. The driving shaft 13 synchronously drives the swash plate 12 to rotate. When the swash plate 12 rotates, the height position of the connecting rod 14 changes, forming an up and down reciprocating motion state. Assuming that the connecting rod 14 starts to move up from the lowest stroke position, during the upward movement, the piston 221 is driven to move up. At this time, the floating retaining ring 2211 in the piston 221 is pressed on the through hole on the bottom end face of the piston 221 due to the negative pressure, and the piston 221 draws the water near the outside of the suspended matter absorber 2 into the air In the cavity 22, during this process, the protrusion is located in the longitudinal groove 2241 and moves. When the piston 221 moves to a position close to the highest stroke, the protrusion enters the spiral groove 2242. In the process of continuing to move upward, the sleeve 224 rotates until the absorption hole 223 at the bottom is closed. At this time, the piston 221 reaches the highest stroke position and starts to move downward. In the above process, due to the effect of centrifugal separation, the suspended matter content in the water body at this position is relatively high. Therefore, most of the pollutants suspended in the water can be removed in this step. After the piston 221 reaches the highest stroke position, it starts to move downward. At this time, the protrusion enters another longitudinal groove 2241 and does not act on the sleeve 224. When the piston 221 moves downward, the sewage in the cavity 22 is pressurized. At this time, the sewage can only enter it from the through hole on the bottom end face of the piston 221. The sewage in the lower piston 221 will be transported upward through the connecting pipe 222, and finally the sewage will be pressed into the water outlet 21 and sent to the connecting port 33 through the pipe 211. The suspended pollutants in the sewage can be removed under the reciprocating cycle;

[0034] Relatively small suspended pollutants form a scum layer on the surface of the water body along with microbubbles. The scum layer gathers to the filter tank 3 on one side under the action of the cyclonic force and enters the filter assembly from the notch of the through slot. The scum is filtered on the filter screen 35 and leaves solid matter. The oil flows from the filter screen 35 to the bottom and gathers, and is discharged to the outside of the tank through the oil outlet 311. By designing the relevant parameters of the gear meshing transmission of the rack and the gear, the connecting rod 14 makes the gear rotate half a circle in one stroke, that is, the filter assembly is in a reciprocating rotation state of 180°. When the upper When the filter screen 35 rotates to the inside of the filter tank 3, the separation cylinder 39 begins to rotate out and gradually closes the slot of the through slot, and the filter screen 35 at the bottom begins to rotate upward to realize the switching of the filter screen 35. After the filter screen 35 enters the bottom, the sewage containing suspended matter pressed into the connection port 33 flows from the water hole 331 at the bottom of the filter component to the other side. During the flow, the contact with the filter screen 35 will wash down the suspended matter filtered on the filter screen 35 and discharge it out of the tank from the suspended matter outlet 321, thereby realizing the separation of oil and solid residue in the scum.

[0035] It will be apparent to those skilled in the art that the 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 the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0036] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An air flotation device for treating oil and gas field wastewater, comprising: An air flotation tank (1), a suspended matter absorber (2) and a filter tank (3), wherein a driving device (11) is installed on the top of the air flotation tank (1), the driving device (11) is connected to a driving shaft (13), the bottom end of the driving shaft (13) is connected to an impeller (15), the impeller (15) is located at the bottom of the air flotation tank (1) and is rotatably connected to the air flotation tank (1), and a micro-nano bubble generating device (16) is arranged at the bottom of the air flotation tank (1) below the impeller (15); The invention is characterized in 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 flotation tank (1), a plurality of cavities (22) are arranged in the suspended matter absorber (2), adjacent cavities (22) are separated by pipe plugs (24), pistons (221) are arranged in the cavities (22), the pistons (221) in adjacent cavities (22) are connected by pipes (222), and the pipes (222) are communicated with the inside of the pistons (221), the bottom end surface of the pistons (221) is provided with a through hole, and the side surface of the suspended matter absorber (2) is provided with an absorption hole (223) at the bottom end position of each cavity (22); The filter tank (3) is arranged near the top of the flotation tank (1). The filter tank (3) is a horizontal tube structure, a through groove is arranged on the top surface, and a filter assembly is arranged inside. The filter assembly is composed of a rotating shaft (36), two groups of filter screens (35) and two groups of partition plates (34) respectively connected to the rotating shaft (36), and two groups of end panels at both ends of the rotating shaft (36). The two groups of end panels are respectively fixed to the two ends of the filter tank (3). The rotating shaft (36) is rotatably connected to the end panels. The two groups of filter screens (35) and the two groups of partition plates (34) are arranged alternately in sequence and are perpendicular to each other. A swash plate (12) is also provided at the top of the flotation tank (1), the swash plate (12) being rotatably connected to the flotation tank (1), a connecting rod (14) being movably connected to the bottom end of the swash plate (12), the connecting rod (14) being connected to a connecting head (23) located at the top end of the suspended matter absorber (2), the connecting head (23) being connected to the uppermost piston (221); a rack structure (141) is provided on the connecting rod (14) at the position of the gear mechanism (37).

2. The flotation device for treating oil and gas field wastewater according to claim 1, characterized in that: A floating retaining ring (2211) is arranged inside the piston (221) and above the through hole.

3. The flotation device for treating oil and gas field wastewater according to claim 1, characterized in that: A sleeve (224) is provided between the piston (221) and the suspended matter absorber (2), and a hollow groove is provided on the side of the sleeve (224), wherein the hollow groove is composed of two sections of longitudinal grooves (2241) and two sections of spiral grooves (2242) in a spiral direction, and the two sections of longitudinal grooves (2241) and the two sections of spiral grooves (2242) are connected end to end in sequence.

4. The flotation device for treating oil and gas field wastewater according to claim 3 is characterized by: A valve hole (2243) is provided on the side surface of the bottom end of the sleeve (224) at a position corresponding to the absorption hole (223).

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

6. The flotation device for treating oil and gas field wastewater according to claim 1 or 5, characterized in that: The filter tank (3) is connected to an oil baffle (38) on one side of the through tank.

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

8. The flotation device for treating oil and gas field wastewater according to claim 1, characterized in that: A connection port (33) is provided at one end of the filter tank (3), and the connection port (33) is connected to a water outlet (21) through a pipe (211). The water outlet (21) is provided on the top side of the suspended matter absorber (2), and a water hole (331) is provided on the end panel of the filter assembly located at this end.

9. The flotation device for treating oil and gas field wastewater according to claim 8, characterized in that: The filter tank (3) is provided with a gear mechanism (37) at one end opposite to the connection port (33), the gear mechanism (37) being connected to the rotating shaft (36), the filter assembly is provided with a suspended matter outlet (321) at the bottom of the end, the suspended matter outlet (321) being connected to a suspended matter discharge pipe (32), and the filter assembly is provided with an oil outlet hole (311) on an end panel located at the end, the oil outlet hole (311) being connected to an oil discharge pipe (31).

10. The flotation device for treating oil and gas field wastewater according to claim 1, characterized in that: There is rotation damping between the rotating shaft (36) and the end panel.

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