A cyclone oil removal device and oil-water separation process

Abstract

The application relates to the technical field of air floatation oil removal, and discloses a cyclone air floatation oil removal device and an oil-water separation process. The cyclone air floatation oil removal device comprises a tank body; further comprises a cyclone assembly arranged in the tank body, the cyclone assembly comprises a cylinder body fixedly installed in the tank body; a gas distribution assembly coaxially arranged at the bottom of a mixing cavity, the gas distribution assembly comprises a gas distribution disc rotationally arranged at the bottom of the mixing cavity, an air inlet pipe penetratingly connected with the center of the bottom of the gas distribution disc, a plurality of groups of cylindrical air holes arrayed in the radial direction of the gas distribution disc, a plurality of groups of spiral cover plates covered above the gas distribution disc, and a plurality of groups of conical air holes corresponding to the cylindrical air holes and arranged on the spiral cover plates. The cyclone air floatation oil removal device drives the intermittent rotation of the gas distribution disc, so that the cylindrical air holes and the conical air holes of the spiral cover plates are alternately corresponding, thereby generating micro air bubbles and large air bubbles suitable for different particle size oil droplets, and the effective capture of micro oil droplets and the rapid separation of medium and large oil droplets are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air flotation oil removal, and particularly relates to a cyclone air flotation oil removal device and an oil-water separation process. BACKGROUND

[0002] The cyclone air flotation oil removal device is a high-efficiency oil-water separation device integrating cyclone separation technology and air flotation separation technology, and is widely applied to oil-containing wastewater treatment scenes in the fields of petroleum chemical industry, steel metallurgy, and oil-containing wastewater of ships. In the specific working process, the oil-containing wastewater forms a rotating flow field in the cyclone cavity, and oil droplets are gathered to the center of the cavity and water phase migrates to the cavity wall under the action of centrifugal force by using the density difference between oil phase and water phase, so that preliminary oil-water layering is completed. At the same time, the oil-containing wastewater is introduced into the air flotation tank, and air bubbles are introduced. The air bubbles adhere to the oil droplets and impurity floc in the wastewater by surface tension, form composite flocs with a density much smaller than water, and float to the surface of the wastewater under the action of Archimedes buoyancy.

[0003] The existing patent with the publication number CN115124104A discloses a cyclone air flotation oil removal system for oil-containing wastewater, which comprises a storage tank, a cyclone, a pressure gas dissolving tank, a bubble generator, an air compressor, and an air flotation oil removal tank. The storage tank is connected to the inlet of the cyclone through a first lifting pump, the outlet of the cyclone is connected to the inlet one of the pressure gas dissolving tank, the bubble generator is connected to the inlet two of the pressure gas dissolving tank through a second lifting pump, the air compressor is connected to the inlet three of the pressure gas dissolving tank, and the outlet of the pressure gas dissolving tank is connected to the air flotation oil removal tank through a third lifting pump. The top of the air flotation oil removal tank is provided with a through hole and a liquid collecting groove, and the liquid collecting groove is arranged around the peripheral wall of the air flotation oil removal tank and below the through hole. Although the above technical solution can remove oil by the cooperation of the cyclone and the air flotation oil removal tank, it has the advantage of reducing the corrosion of the treatment equipment.

[0004] In the prior art, the generation of air bubbles in the air flotation tank is mainly through the release of pressurized gas dissolved by the gas dissolving pump or directly into the wastewater through the gas hole structure of the aeration disc. However, the generated air bubbles are generally of a single size, or are micro-bubbles or large bubbles, which are difficult to adapt to the separation requirements of oil droplets of different particle sizes in oil-containing wastewater. If only micro-bubbles are used, although they can form effective adhesion with micro oil droplets in the wastewater, the slow rising speed of micro-bubbles and the weak disturbance effect on the wastewater make it difficult for the demulsifier and flocculant in the wastewater to fully mix with the oil-water emulsion, and part of the medium and large oil droplets are difficult to coalesce due to insufficient contact with air bubbles. If only large bubbles are used, although they can quickly carry medium and large oil droplets to the surface by large buoyancy, the specific surface area of the medium and large bubbles is significantly reduced, the collision contact probability with micro oil droplets is greatly reduced, and the problem of insufficient capture efficiency of micro oil droplets is easily caused. SUMMARY

[0005] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0006] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0007] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0008] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0009] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0010] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0011] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0012] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0013] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0014] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0015] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0016] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0017] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0018] The oil-water separation process and the oil removal device of the application can solve the problem of single bubble size in the existing flotation tank, and can meet the separation requirements of oil droplets with different particle sizes in oily sewage.

[0019] Further, the inner wall of the pre-rotation cavity is provided with a plurality of groups of guide vanes arranged in the circumferential direction, the inner wall of the rotational flow cavity is provided with a plurality of groups of rotational flow vanes and a plurality of groups of steady flow vanes arranged in the circumferential direction, wherein the rotational flow vanes are located below the steady flow vanes, and the directions of the rotational flow vanes and the steady flow vanes are opposite.

[0020] Further, the driving mechanism comprises a motor mounted on the inner wall of the tank at the bottom, an incomplete gear fixedly connected with the output end of the motor, and a driven gear engaged with the incomplete gear, the driven gear being fixedly connected to the outer surface of the air inlet pipe.

[0021] Further, the driving mechanism further comprises turbulence rods equidistantly distributed in the circumferential direction of the air distribution disc, the top of each turbulence rod is symmetrically provided with two groups of turbulence vanes, the bottom of each turbulence rod is fixedly connected with a pinion, and the circumferential edge of the upper surface of the air distribution disc is fixedly connected with a gear ring, the inner ring gear of the gear ring being engaged with the pinion.

[0022] The inner wall of the mixing cavity is fixedly connected with a support frame corresponding to each turbulence rod, and each turbulence rod is rotationally connected with the support frame through a bearing.

[0023] Further, the inner diameter of the bottom of the conical air hole is equal to the inner diameter of the cylindrical air hole, and the inner diameter of the top of the conical air hole is smaller than the inner diameter of the cylindrical air hole.

[0024] Further, a plurality of groups of the cylindrical air holes are distributed in the form of multiple equidistant spiral lines in the radial direction of the air distribution disc.

[0025] Further, the guide vanes, the rotational flow vanes, and the steady flow vanes are arranged in an alternating manner.

[0026] Further, the guide vanes comprise an integrally formed arc segment and a vertical segment, and the vertical segment extends vertically downward to the junction of the pre-rotation cavity and the mixing cavity.

[0027] Further, the steady flow vanes comprise an integrally formed spiral segment and a radial segment, and the radial segment extends to the inside of the steady flow cavity.

[0028] A rotational flow air flotation oil-water separation process using the rotational flow air flotation oil removal device, comprising the following steps:

[0029] Step one: pretreating the oily wastewater by coarse filtration or shallow sedimentation process to remove suspended particles and block-shaped impurities with larger particle size in the water;

[0030] Step two: adding a demulsifier and a flocculant to the pretreated oily wastewater, and preliminarily stirring through a static mixer;

[0031] Step three: the oil-containing sewage after adding medicine is sent into a cylindrical cyclone, and the centrifugal force generated by high-speed rotation of the cyclone tube is used to realize uniform mixing of the medicine and the oil-water emulsion, high-efficiency demulsification, and at the same time, to push the micro oil droplets to coalesce to form large oil clusters, and to preliminarily separate part of the floating oil, and the water phase after separation is introduced into the tank body;

[0032] Step four: the pressurized gas is introduced into the tank body through the gas injection pipe, so that the gas is fully dissolved in the above-mentioned water phase to form high-concentration dissolved gas water;

[0033] Step five: the pressure in the tank body is suddenly reduced, so that the dissolved gas is precipitated to form bubbles, and the bubbles are closely adhered to the residual oil droplets and impurity floc in the water under the action of surface tension to form composite floc with a density less than water;

[0034] Step six: the cyclone assembly in the tank body is used to make the mixed liquid form a cyclone, so as to prolong the contact time and migration path of the composite floc and the bubbles;

[0035] Step seven: the composite floc floats to the top of the tank body under the action of Archimedes' buoyancy to form a floating oil layer, and is discharged through the first oil outlet pipe;

[0036] Step eight: the residual water phase in the cyclone assembly enters the annular area between the tank body and the cyclone assembly through the liquid outlet pipe, and the secondary air flotation environment is formed by continuously injecting air through the air supplement pipe, so as to further capture residual oil droplets;

[0037] Step nine: the oil dirt generated by the secondary air flotation is discharged through the second oil outlet pipe, and the treated clean water is discharged through the water outlet pipe.

[0038] The beneficial effects of the present application are as follows:

[0039] By setting the cyclone assembly, the air distribution assembly and the driving mechanism, the cylindrical air holes and the conical air holes of the spiral cover plate are alternately corresponding by driving the air distribution disc to rotate intermittently, so that the micro bubbles and large bubbles suitable for different particle size oil droplets are generated, the effective capture of the micro oil droplets and the rapid separation of the medium and large oil droplets are realized, the adaptation range of the device to different oil-containing sewage is effectively improved, the problems of insufficient mixing and low capture efficiency caused by single bubble size are avoided, and at the same time, the spoiler rotates synchronously with the air distribution disc, the dead water area at the edge of the mixing chamber is eliminated, the bubble agglomeration is dispersed, and the uniform mixing of the gas-liquid-oil three phases is further improved.

[0040] By setting the guide vane, the cyclone vane and the steady flow vane, the mixed liquid in the mixing chamber can be smoothly introduced into the pre-rotation cavity and form a stable cyclone by cooperation of the arc segment and the vertical segment of the guide vane, the cyclone vane and the steady flow vane are reversely arranged, the cyclone intensity of the mixed liquid can be gradually weakened, the oil droplets that have been preliminarily coalesced are prevented from being dispersed due to too strong cyclone, at the same time, the migration path and time of the oil droplets and the impurity floc in the mixed liquid are prolonged, the adhesion probability of the oil droplets and the impurity floc and the bubbles is increased, and the separation efficiency is improved. Attached Figure Description

[0041] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0042] Figure 2 This is a front view of the cross-sectional structure of the present invention;

[0043] Figure 3 This is a schematic cross-sectional view of the three-dimensional structure of the cylindrical body of the present invention;

[0044] Figure 4 This is a three-dimensional cross-sectional schematic diagram of the air injection pipe and air distribution assembly of the present invention.

[0045] Figure 5 This is an exploded three-dimensional structural diagram of the air distribution plate and spiral cover plate of the present invention;

[0046] Figure 6 This is a partial three-dimensional cross-sectional view of the spiral cover plate of the present invention;

[0047] Figure 7 This is a three-dimensional structural diagram of the air distribution plate, air inlet pipe, spiral cover plate, conical air hole and drive mechanism of the present invention;

[0048] Figure 8 This is a three-dimensional structural diagram of the air distribution plate, air inlet pipe, cylindrical air hole and drive mechanism of the present invention.

[0049] Figure 9 This is a three-dimensional cross-sectional view of the drive mechanism of the present invention;

[0050] Figure 10 This is a bottom view of the three-dimensional structure of the cylindrical body of the present invention;

[0051] Figure 11 This is an exploded three-dimensional structural diagram of the guide vane, swirl vane, and flow stabilizer vane of the present invention.

[0052] In the picture:

[0053] 1. Tank body; 2. Air injection pipe; 3. Swirl assembly; 31. Cylinder; 32. Mixing chamber; 33. Pre-swirling chamber; 34. Swirl chamber; 35. Flow stabilizing chamber; 36. Sludge collection chamber; 4. Liquid inlet pipe; 5. Air distribution assembly; 51. Air distribution plate; 52. Air inlet pipe; 53. Cylindrical air hole; 54. Spiral cover plate; 55. Conical air hole; 56. Connecting column; 57. L-shaped bracket; 6. Drive mechanism; 61. Motor; 62. Incomplete 63. Driven gear; 64. Baffle rod; 65. Baffle blade; 66. Pinion; 67. Gear ring; 68. Support frame; 7. First oil outlet pipe; 8. Liquid outlet pipe; 9. Air supply pipe; 10. Second oil outlet pipe; 11. Water outlet pipe; 12. Guide vane; 121. Arc-shaped section; 122. Vertical section; 13. Swirl blade; 14. Flow stabilizing blade; 141. Spiral section; 142. Radial section; 15. Air outlet pipe. Detailed Implementation

[0054] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0055] Example 1, refer to Figures 1-2 The present invention provides a cyclone flotation oil removal device, including a tank 1 and an air injection pipe 2 coaxially disposed on the inner wall of the bottom of the tank 1, and further including:

[0056] The swirl assembly 3 is installed inside the tank 1.

[0057] Specifically, refer to Figures 2-3 The swirl assembly 3 includes a cylindrical body 31 fixedly installed inside the tank 1. The cylindrical body 31 has a mixing chamber 32, a pre-swirl chamber 33, a swirl chamber 34, a flow stabilizing chamber 35, and a sludge collection chamber 36 that are sequentially opened from bottom to top. An annular area is formed between the inner wall of the tank 1 and the outer wall of the cylindrical body 31. The annular area is used to form a secondary air flotation environment, which can perform secondary treatment on the residual water phase and further improve the oil removal efficiency.

[0058] The inlet pipe 4 is located on one side of the tank body 1 and extends into the mixing chamber 32. The outlet end of the inlet pipe 4 faces the tangential direction of the inner wall of the mixing chamber 32, which is used to realize the tangential inlet of oily wastewater.

[0059] The air distribution assembly 5 is coaxially disposed at the bottom of the mixing chamber 32.

[0060] Specifically, refer to Figure 2 , Figures 4-6 and Figure 10The air distribution assembly 5 comprises an air distribution disc 51 rotatably arranged at the bottom of the mixing chamber 32, an air inlet pipe 52 connected through the center of the bottom of the air distribution disc 51, a plurality of groups of cylindrical air holes 53 arranged in an array along the radial direction of the air distribution disc 51, a plurality of groups of spiral cover plates 54 covering the air distribution disc 51, and a plurality of groups of conical air holes 55 corresponding to the cylindrical air holes 53 and arranged on the spiral cover plates 54. Elastic diaphragms are arranged in the cylindrical air holes 53 and the conical air holes 55 to allow only airflow to pass through, thereby achieving a one-way sealing function. The inner diameter of the bottom of the conical air hole 55 is equal to the inner diameter of the cylindrical air hole 53, and the inner diameter of the top of the conical air hole 55 is smaller than the inner diameter of the cylindrical air hole 53. The plurality of groups of spiral cover plates 54 are fixedly connected through a connecting column 56, and the outer peripheral end of each group of spiral cover plates 54 is fixedly connected to the inner wall of the mixing chamber 32 through an L-shaped support 57. The air inlet pipe 52 extends into the gas injection pipe 2 and is rotatably connected to the bottom of the tank body 1 through a sealing bearing, allowing the air inlet pipe 52 to rotate in the gas injection pipe 2 while ensuring sealed delivery of the gas. Similarly, the air distribution disc 51 is rotatably connected to the bottom of the mixing chamber 32 through a sealing bearing, effectively sealing the bottom of the mixing chamber 32 and preventing leakage of the medium in the mixing chamber 32.

[0061] It should be noted that the plurality of groups of cylindrical air holes 53 are distributed in multiple circles of equidistant spiral lines along the radial direction of the air distribution disc 51. The cylindrical air holes 53 arranged in spiral lines can guide the gas to be discharged along a spiral path, thereby enhancing the shearing contact between the gas and the oil-contaminated water in the mixing chamber 32, promoting the more uniform dispersion of the gas bubbles into the liquid, and avoiding local bubble concentration.

[0062] During use, when the air distribution disc 51 is intermittently rotated to place the cylindrical air holes 53 in a corresponding state with the conical air holes 55, the high-pressure gas delivered by the air inlet pipe 52 enters the inside of the air distribution disc 51 and then flows upward along the cylindrical air holes 53 and enters the corresponding conical air holes 55. Since the inner diameter of the bottom of the conical air hole 55 is equal to the inner diameter of the cylindrical air hole 53, and the inner diameter of the top of the conical air hole 55 is smaller than the inner diameter of the cylindrical air hole 53, the airflow in the conical air hole 55 is squeezed and accelerated, and finally released in the form of high-speed jet from the top of the conical air hole 55, breaking into tiny bubbles. When the air distribution disc 51 is intermittently rotated to place the cylindrical air holes 53 in a staggered state with the conical air holes 55, the airflow directly flows upward from the cylindrical air holes 53, and large bubbles are released at this time. The tiny bubbles can fully contact with the tiny oil droplets suspended in the water body, forming a stable composite flocculation structure that is not easily broken by flow field disturbance during the rising process, avoiding the re-dispersion of oil droplets into the water. The large bubbles can quickly carry medium and large oil droplets to float, and by alternating the generation of the two types of bubbles, the problems of insufficient mixing and low capture efficiency caused by a single bubble size are avoided.

[0063] The driving mechanism 6 is arranged at the bottom of the inner wall of the tank body 1 and is used to drive the air distribution disc 51 to rotate intermittently.

[0064] Specifically, referring to Figures 7-8 , the driving mechanism 6 includes a motor 61 mounted on the inner wall bottom of the tank body 1, an incomplete gear 62 fixedly connected with the output end of the motor 61, and a driven gear 63 engaged with the incomplete gear 62. The driven gear 63 is fixedly connected to the outer surface of the air inlet pipe 52. The cylindrical air holes 53 on the air distribution disc 51 are in a corresponding state with the conical air holes 55 on the spiral cover plate 54. When the incomplete gear 62 drives the driven gear 63 to complete one rotation, the air distribution disc 51 rotates by a corresponding angle with the driven gear 63, and the cylindrical air holes 53 move to between two adjacent spiral cover plates 54, so that the gas is directly discharged from the cylindrical air holes 53 without passing through the conical air holes 55, forming large bubbles. When the incomplete gear 62 drives the driven gear 63 to rotate by the same angle again, the air distribution disc 51 rotates by a corresponding angle with the driven gear 63 again, and the cylindrical air holes 53 are in a corresponding state with the conical air holes 55 on the corresponding spiral cover plate 54, thereby realizing the alternate generation of micro-bubbles and large bubbles.

[0065] Further, referring to Figures 9-10 , the driving mechanism 6 further includes turbulence rods 64 equidistantly distributed along the circumferential direction of the air distribution disc 51. The top of the turbulence rod 64 is symmetrically provided with two groups of turbulence vanes 65. The bottom of the turbulence rod 64 is fixedly connected with a pinion 66. The circumferential edge of the upper surface of the air distribution disc 51 is fixedly connected with a gear ring 67. The inner ring gear of the gear ring 67 is engaged with the pinion 66. There is a gap between the gear ring 67 and the L-shaped support 57. Therefore, when the air distribution disc 51 rotates, the gear ring 67 will not come into contact with the L-shaped support 57. When the air distribution disc 51 rotates, the gear ring 67 will rotate together. Through the engagement of the gear ring 67 and the pinion 66, the turbulence rod 64 and the turbulence vane 65 rotate synchronously. The turbulence vane 65 is inclined, which can disturb the mixed liquid in the edge area of the mixing chamber 32 during rotation, thereby avoiding the formation of a dead water area in the edge area, and also dispersing the bubbles gathered in the edge area, so that the gas, liquid and oil in the edge and center areas of the mixing chamber 32 can be efficiently mixed.

[0066] The inner wall of the mixing chamber 32 is fixedly connected with a support frame 68 corresponding to the turbulence rod 64. The turbulence rod 64 is rotatably connected with the support frame 68 through a bearing. The support frame 68 provides support for the turbulence rod 64.

[0067] Among them, referring to Figures 1-2 , the top of the tank body 1 is provided with a first oil outlet pipe 7. The first oil outlet pipe 7 extends into the sewage collection chamber 36. The inlet end of the first oil outlet pipe 7 is close to the top of the sewage collection chamber 36, which is used to discharge the accumulated floating oil in the sewage collection chamber 36.

[0068] The liquid outlet pipe 8 is arranged at a lower position in the sewage collecting cavity 36 and is arrayed along the circumferential direction of the sewage collecting cavity 36. The outlet end of the liquid outlet pipe 8 is located in the annular region formed between the tank body 1 and the cylinder body 31, and is used to guide the residual water phase in the sewage collecting cavity 36 after treatment to the secondary gas floatation.

[0069] The air supplement pipe 9 is arranged on one side of the tank body 1 and has an air outlet end penetrating into the annular region formed between the tank body 1 and the cylinder body 31. The air supplement pipe 9 is provided with a one-way valve and is used to supplement high-pressure gas into the annular region.

[0070] The second oil outlet pipe 10 is arranged above one side of the tank body 1, penetrates through the side wall of the tank body 1 and communicates with the annular region, and is used to discharge the secondary floating oil in the annular region.

[0071] The water outlet pipe 11 is arranged below one side of the tank body 1, penetrates through the side wall of the tank body 1 and communicates with the annular region. The water outlet pipe 11 is provided with a flow control valve and is used to discharge the clean water after final treatment.

[0072] The gas outlet pipe 15 is further arranged on the top of the tank body 1 and is used to discharge the accumulated gas in the tank body 1.

[0073] Further, referring to Figure 2 and Figure 11 , a plurality of groups of guide vanes 12 are arrayed along the circumferential direction of the inner wall of the pre-rotation cavity 33. Specifically, the guide vanes 12 include an integrally formed arc segment 121 and a vertical segment 122. The vertical segment 122 extends vertically downward to the junction of the pre-rotation cavity 33 and the mixing cavity 32. The curvature of the arc segment 121 is matched with the inner wall of the pre-rotation cavity 33 and can guide the mixed liquid to flow along an arc path in close contact with the cavity wall. The vertical segment 122 can directly guide the mixed liquid discharged from the mixing cavity 32, and its role is to enable the mixed liquid to smoothly transition when entering the pre-rotation cavity 33 from the mixing cavity 32.

[0074] A plurality of groups of rotational flow vanes 13 and a plurality of groups of stable flow vanes 14 are arrayed along the circumferential direction of the inner wall of the rotational flow cavity 34. The rotational flow vanes 13 are located below the stable flow vanes 14, and the directions of the rotational flow vanes 13 and the stable flow vanes 14 are opposite. The mixed liquid entering the rotational flow cavity 34 from the pre-rotation cavity 33 still has a certain rotational flow kinetic energy. At this time, the lower rotational flow vanes 13 can produce a guiding effect on the mixed liquid. When the mixed liquid flows upward to the region of the stable flow vanes 14, the oppositely arranged stable flow vanes 14 can gradually weaken the rotational flow intensity of the mixed liquid, avoid the oil droplets that have been preliminarily aggregated from being dispersed due to excessively strong rotational flow, and at the same time, prolong the migration path and time of the oil droplets and impurity floc in the mixed liquid, increase the adhesion probability of the oil droplets and impurity floc and gas bubbles, and improve the separation efficiency.

[0075] Specifically, the steady flow blade 14 includes an integral spiral section 141 and a radial section 142, the radial section 142 extends to the inside of the steady flow cavity 35, the spiral guide of the spiral section 141 gradually reduces the rotation speed of the mixed liquid, when the mixed liquid flows to the radial section 142, the mixed liquid entering the steady flow cavity 35 is in a steady laminar flow state, so that the gathered oil droplets can stably float to the oil collection cavity 36 under the action of buoyancy, avoiding the up-and-down rolling of the oil droplets caused by the rotational flow, and further improving the efficiency and stability of oil-water separation.

[0076] The guide blade 12, the rotational flow blade 13 and the steady flow blade 14 are arranged in a staggered manner, so that the mixed liquid smoothly transitions between the chambers, when the mixed liquid enters the pre-rotation cavity 33 from the mixing cavity 32, it first contacts the guide force of the guide blade 12 to form a preliminary rotational flow, then the mixed liquid enters the lower part of the rotational flow cavity 34 and contacts the rotational flow blade 13, when the mixed liquid continues to flow upward through the upper part of the rotational flow cavity 34, it contacts the steady flow blade 14, so that the mixed liquid can smoothly transition from the rotational flow state of the rotational flow blade 13 to the steady flow state of the steady flow blade 14.

[0077] The working principle of the rotational flow air flotation oil removal device is as follows: the oil-containing sewage is transported into the mixing cavity 32 of the rotational flow assembly 3 through the liquid inlet pipe 4, and the motor 61 is started to drive the incomplete gear 62 to rotate, and through the intermittent meshing with the driven gear 63, the air inlet pipe 52 and the air distribution disc 51 are driven to rotate intermittently, during the rotation of the air distribution disc 51, the air inlet pipe 52 at the bottom of the air distribution disc 51 guides the high-pressure gas in the air injection pipe 2 into the air distribution disc 51, when the cylindrical air hole 53 on the air distribution disc 51 corresponds to the conical air hole 55 on the spiral cover plate 54, the gas enters the conical air hole 55 through the cylindrical air hole 53, and under the extrusion and acceleration of the conical flow channel, micro bubbles are formed, the micro bubbles and the micro oil droplets in the mixing cavity 32 fully contact to form stable composite flocs, when the air distribution disc 51 continues to rotate to misalign the cylindrical air hole 53 and the conical air hole 55, the gas is directly discharged from the cylindrical air hole 53 to form large bubbles, the large bubbles quickly carry the medium and large oil droplets to float up, at the same time, when the air distribution disc 51 rotates, the tooth ring 67 at the edge of the air distribution disc 51 drives the pinion 66 to rotate, so that the turbulence rod 64 and the turbulence blade 65 rotate synchronously, the mixed liquid in the edge area of the mixing cavity 32 is disturbed to avoid the formation of dead water area, and the agglomeration of bubbles is dispersed, so that the gas, liquid and oil three phases are uniformly mixed.

[0078] The mixed gas-liquid-oil mixture enters the pre-rotation cavity 33, is preliminarily guided by the vertical section 122 of the guide blade 12 and the arc-shaped section 121 of the guide blade 12, and the oil droplets are preliminarily gathered, then the mixed liquid enters the rotational flow cavity 34, the lower part of the rotational flow blade 13 makes the mixed liquid continue to form a rotational flow, and the upper part of the steady flow blade 14 gradually reduces the rotation speed through the spiral section 141, and then the rotational flow is converted into vertical laminar flow through the radial section 142 and is guided into the steady flow cavity 35.

[0079] Under the laminar flow state in the steady flow cavity 35, the composite flocculation and oil droplets are stably floated to the sludge collection cavity 36 under the action of buoyancy, the floating oil is discharged through the first oil outlet pipe 7, the residual water phase in the sludge collection cavity 36 is introduced into the annular area formed by the tank body 1 and the cylinder body 31 through the liquid outlet pipe 8, the air supplement pipe 9 supplements high-pressure gas to the annular area for secondary air flotation, further captures residual oil droplets, the secondary floating oil is discharged through the second oil outlet pipe 10, and finally the treated clean water is discharged after being regulated by the flow control valve on the water outlet pipe 11, thereby completing the whole cyclonic air flotation oil removal process.

[0080] In the second embodiment, the application further provides a cyclonic air flotation oil-water separation process, which adopts the cyclonic air flotation oil removal device and includes the following steps.

[0081] Step one: the oily wastewater is pretreated by coarse filtration or shallow sedimentation process to remove suspended particles and block impurities with large particle size in the water;

[0082] Step two: the demulsifier and flocculant are added to the pretreated oily wastewater, and the mixture is preliminarily stirred by the static mixer;

[0083] Step three: the dosed oily wastewater is sent into the cylindrical cyclone, the centrifugal force generated by the high-speed rotation of the cyclone tube is used to realize the uniform mixing of the medicament and the oil-water emulsion, high-efficiency demulsification, and the aggregation of the micro oil droplets to form large oil clusters, and part of the floating oil is preliminarily separated, and the water phase after separation is introduced into the tank body 1;

[0084] Step four: the pressurized gas is introduced into the tank body 1 through the air injection pipe 2, so that the gas is fully dissolved in the above-mentioned water phase to form high-concentration dissolved gas water;

[0085] Step five: the pressure in the tank body 1 is suddenly reduced to promote the precipitation of the dissolved gas to form bubbles, and the bubbles are closely adhered to the residual oil droplets and impurity flocculation in the water under the action of surface tension to form composite flocculation with a density less than water;

[0086] Step six: the cyclone assembly 3 in the tank body 1 is used to make the mixed liquid form a cyclone to prolong the contact time and migration path of the composite flocculation and the bubbles;

[0087] Step seven: the composite flocculation is floated to the top of the tank body 1 under the action of the Archimedes buoyancy to form a floating oil layer, which is discharged through the first oil outlet pipe 7;

[0088] Step eight: the residual water phase in the cyclone assembly 3 is introduced into the annular area between the tank body 1 and the cyclone assembly 3 through the liquid outlet pipe 8, and the air injection pipe 9 continuously injects air to form a secondary air flotation environment to further capture residual oil droplets;

[0089] Step nine: the oil sludge generated by the secondary air flotation is discharged through the second oil outlet pipe 10, and the treated clean water is discharged through the water outlet pipe 11.

[0090] It should be noted that the above examples are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced, without departing from the spirit and scope of the technical solutions of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. A cyclone flotation oil removal device, comprising: Tank body; The gas injection pipe, coaxially arranged on the inner wall of the bottom of the tank, is characterized by further comprising: A swirl assembly is disposed inside the tank. The swirl assembly includes a cylindrical body fixedly installed inside the tank. The cylindrical body is provided with a mixing chamber, a pre-swirl chamber, a swirl chamber, a flow stabilizing chamber, and a sludge collection chamber, which are sequentially opened from bottom to top. The inlet pipe is located on one side of the tank and extends into the mixing chamber; A gas distribution assembly is coaxially disposed at the bottom of the mixing chamber. The gas distribution assembly includes a gas distribution plate rotatably disposed at the bottom of the mixing chamber, an air inlet pipe that is connected through the center of the bottom of the gas distribution plate, multiple sets of cylindrical air holes arranged radially along the gas distribution plate, multiple sets of spiral cover plates covering the gas distribution plate, and conical air holes corresponding to the cylindrical air holes on the spiral cover plates. The multiple sets of spiral cover plates are fixedly connected to each other by connecting columns. The outer periphery of each set of spiral cover plates is fixedly connected to the inner wall of the mixing chamber by an L-shaped bracket. The air inlet pipe extends into the gas injection pipe and is rotatably connected to the bottom of the tank by a sealed bearing. The drive mechanism, located at the bottom of the inner wall of the tank, is used to drive the air distribution plate to rotate intermittently. The first oil outlet pipe is located at the top of the tank and extends into the sludge collection chamber; The liquid outlet pipe is located in the sludge collection chamber near the bottom, and the outlet end of the liquid outlet pipe is located in the annular area between the cylinder and the tank. The gas supply pipe is located on one side of the tank. The second oil outlet pipe is located on the upper side of one side of the tank. The water outlet pipe is located on the lower side of the tank.

2. The cyclone flotation oil removal device according to claim 1, characterized in that: The inner wall of the pre-swirl chamber is arranged with multiple sets of guide blades in a circumferential direction, and the inner wall of the swirling chamber is arranged with multiple sets of swirling blades and multiple sets of stabilizing blades in a circumferential direction. The swirling blades are located below the stabilizing blades, and the swirling blades and stabilizing blades are in opposite directions.

3. The cyclone flotation oil removal device according to claim 1, characterized in that: The drive mechanism includes a motor installed at the bottom of the inner wall of the tank, an incomplete gear fixedly connected to the output end of the motor, and a driven gear meshing with the incomplete gear. The driven gear is fixedly connected to the outer surface of the air inlet pipe.

4. The cyclone flotation oil removal device according to claim 3, characterized in that: The drive mechanism also includes eccentrically distributed baffle rods along the circumference of the air distribution plate. Two sets of baffle blades are symmetrically arranged at the top of the baffle rods. A small gear is fixedly connected to the bottom of the baffle rods. A toothed ring is fixedly connected to the circumferential edge of the upper surface of the air distribution plate. The inner toothed ring of the toothed ring meshes with the small gear. The inner wall of the mixing chamber is fixedly connected to a support frame that corresponds to a baffle rod. The baffle rod is rotatably connected to the support frame through a bearing.

5. The cyclone flotation oil removal device according to claim 1, characterized in that: The inner diameter of the bottom of the conical vent is equal to the inner diameter of the cylindrical vent, while the inner diameter of the top of the conical vent is smaller than the inner diameter of the cylindrical vent.

6. The cyclone flotation oil removal device according to claim 1, characterized in that: The multiple sets of cylindrical air holes are distributed in a spiral pattern with equal spacing along the radial direction of the air distribution plate.

7. The cyclone flotation oil removal device according to claim 2, characterized in that: The guide vanes, swirl vanes, and flow stabilizers are arranged alternately at intervals.

8. The cyclone flotation oil removal device according to claim 2, characterized in that: The guide blade includes an integrally formed arc-shaped section and a vertical section, with the vertical section extending vertically downward to the junction of the pre-swirl chamber and the mixing chamber.

9. The cyclone flotation oil removal device according to claim 2, characterized in that: The flow-stabilizing blade includes an integrally formed helical section and a radial section, with the radial section extending into the flow-stabilizing cavity.

10. A cyclone flotation oil-water separation process, employing the cyclone flotation oil removal device as described in claim 1, characterized in that, Includes the following steps: Step 1: Pre-treat oily wastewater by removing large suspended particles and lumpy impurities through coarse filtration or shallow sedimentation. Step 2: Add demulsifier and flocculant to the pretreated oily wastewater and stir it initially using a static mixer; Step 3: The oily wastewater after dosing is sent into a column hydrocyclone. With the help of the centrifugal force generated by the high-speed swirling of the hydrocyclone tube, the agent and the oil-water emulsion are mixed evenly and the emulsion is broken efficiently. At the same time, the tiny oil droplets are pushed to aggregate and form large oil clumps, and some floating oil is initially separated. The separated aqueous phase is then introduced into the tank. Step 4: Introduce pressurized gas into the tank through the gas injection pipe to fully dissolve the gas in the aqueous phase above, forming high-concentration dissolved gas water; Step 5: The pressure inside the tank drops sharply, causing dissolved gas to precipitate and form bubbles. The bubbles adhere tightly to residual oil droplets and impurity flocs in the water under the action of surface tension, forming a composite floc with a density less than that of water. Step Six: Use the swirling assembly inside the tank to create a swirling flow in the mixture, extending the contact time and migration path between the composite flocs and the bubbles; Step 7: The composite flocs float to the top of the tank's sludge collection chamber under the action of Archimedes buoyancy, forming a floating oil layer, which is then discharged through the first oil outlet pipe; Step 8: The residual aqueous phase in the cyclone assembly enters the annular area between the tank and the cyclone assembly through the liquid outlet pipe, and is continuously injected with air through the air supply pipe to form a secondary air flotation environment to further capture residual oil droplets. Step 9: The oil sludge generated by the secondary air flotation is discharged through the second oil outlet pipe, and the treated clean water is discharged through the water outlet pipe.

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