A cyclone separation device and separation method for oily wastewater

Abstract

The present invention discloses a cyclone separation device and a separation method for oily wastewater, the device comprises: a separation cylinder, a cyclone assembly and a bubble making assembly; the cyclone assembly comprises a first cyclone and a second cyclone with a centrifugal force greater than that of the first cyclone; an overflow port is provided at the upper end of the separation cylinder, an outer inverted cone is provided at the lower end, an inner inverted cone is provided inside the outer inverted cone, the inner inverted cone is located below the first cyclone, and a medium water outlet is provided at the lower end of the inner inverted cone; a clean water channel is formed between the outer wall of the inner inverted cone and the inner wall of the outer inverted cone; the bubble making assembly comprises a first bubble making device, a second bubble making device and a centrifugal pump, the first cyclone is used to separate the bubble mixture of the oily wastewater to be treated; the second cyclone is used to separate the medium water bubble mixture produced by the first cyclone. Through the primary and fine cyclone flotation separation of the oily wastewater, the separation of larger particle size oil droplets and fine particle size oil droplets is achieved, the oil-water separation efficiency and separation accuracy are improved, and the oil-water separation speed is accelerated.

Description

Technical Field

[0001] The invention relates to the technical field of oily wastewater treatment, and in particular to an oily wastewater cyclone separation device and a separation method. Background Art

[0002] my country's oil fields have entered the late stage of development with high water content, and the output of produced water has increased year by year. The treatment of oily wastewater is an important problem facing oil field development and environmental protection.

[0003] In practice, the distribution of oil droplet sizes in oily wastewater varies greatly. For example, the droplet size of dissolved oil is generally less than 0.1 μm, and the droplet size of dispersed oil is generally between 10-100 μm, which makes the separation of oily wastewater more stringent.

[0004] The main technologies for treating oily wastewater include physical, chemical, physicochemical and biological methods. The effluent from chemical treatment can generally meet the requirements for reinjection or discharge, but there are problems such as low crude oil recovery rate, large dosage of reagents, production of oily sludge and high operating costs. The biological method decomposes oil into carbon dioxide and water through the metabolism of microorganisms and other life activities. This method is difficult to control the amount of microorganisms attached to the surface of the carrier, so it has poor flexibility in operation and limited volume load.

[0005] Therefore, physical methods, physicochemical methods and multi-physical method integrated technology have gradually become the first choice for oily wastewater treatment technology. Physical methods mainly include flotation separation, cyclone separation and coarse particle separation. Cyclone separation is a separation method based on the density difference between two phases (gas / solid, liquid / solid, gas / liquid, liquid / liquid) and uses centrifugal force to separate the two phases. Although the density difference between oil and water is greater than 0.05g / cm 3 Under the condition of cyclone separation, oil droplets larger than 10 μm can be effectively removed, but the removal rate of oil droplets smaller than 8 μm by single cyclone separation method does not exceed 40%. Therefore, the key to improving the efficiency of cyclone separation treatment of oily wastewater is to optimize the structure design of cyclone separation equipment based on process intensification. Summary of the invention

[0006] The purpose of the present invention is to provide an oily wastewater cyclone separation device and separation method, which has a simple structure and can separate larger particle size oil droplets and fine particle size oil droplets in the oily wastewater through primary and fine cyclone flotation of the oily wastewater, thereby improving the oil-water separation efficiency and accelerating the oil-water separation speed.

[0007] As one aspect of an embodiment of the present invention, an embodiment of the present invention provides an oily wastewater cyclone separation device, comprising: a separation cylinder cyclone component and a bubble making component;

[0008] The cyclone assembly comprises a first cyclone and a second cyclone having a centrifugal force greater than that of the first cyclone, wherein the first cyclone is arranged at the lower part of the separation cylinder, and the second cyclone is arranged at the upper part of the separation cylinder;

[0009] The upper end of the separation cylinder is provided with an overflow port, the lower end of the separation cylinder is provided with an outer inverted cone, an inner inverted cone is provided inside the outer inverted cone, the inner inverted cone is located below the first cyclone, and a medium water outlet is provided at the lower end of the inner inverted cone; a clean water channel is formed between the outer wall of the inner inverted cone and the inner wall of the outer inverted cone;

[0010] The bubble making assembly comprises a first bubble making device, a second bubble making device and a centrifugal pump;

[0011] The first bubble making device is used to mix the oily wastewater to be treated with gas to form a bubble mixture of the oily wastewater to be treated, and the first cyclone is used to separate the bubble mixture of the oily wastewater to be treated so that the separated grey water is discharged from the grey water outlet to the centrifugal pump for pressurization; the second bubble making device is used to mix the pressurized grey water with gas to form a grey water bubble mixture, and the second cyclone is used to separate the grey water bubble mixture.

[0012] In one or some optional embodiments, the liquid outlet of the first bubble making device is connected to the tangential liquid inlet of the first cyclone; the liquid outlet of the second bubble making device is connected to the tangential liquid inlet of the second cyclone; the inlet of the centrifugal pump is connected to the medium water outlet of the inner inverted cone, and the outlet of the centrifugal pump is connected to the liquid inlet of the second bubble making device.

[0013] In one or some optional embodiments, the air inlet of the first bubble making device is used to introduce gas of a first preset pressure; the liquid inlet of the first bubble making device is used to introduce oily wastewater to be treated at a set flow rate;

[0014] The first bubble making device is used to mix the introduced oily wastewater to be treated and the gas of the first preset pressure to form a bubble mixture of the oily wastewater to be treated, and to make the bubble mixture of the oily wastewater to be treated enter the first cyclone tangentially.

[0015] In one or some optional embodiments, the gas inlet of the second bubble making device is used to introduce gas of a second preset pressure;

[0016] The second bubble making device is used for mixing the gas of the second preset pressure and the reclaimed water introduced by the centrifugal pump to form a reclaimed water-bubble mixed liquid, and allowing the reclaimed water-bubble mixed liquid to enter the second cyclone tangentially.

[0017] In one or some optional embodiments, the centrifugal diameter of the second cyclone may be smaller than the centrifugal diameter of the first cyclone.

[0018] In one or some optional embodiments, the number of the second cyclones may be multiple groups, the separation barrel is circular, and the multiple groups of second cyclones are evenly arranged in the separation barrel along the circumferential direction.

[0019] In one or some optional embodiments, the number of the second cyclones may be two or three groups.

[0020] In one or some optional embodiments, a baffle may be provided at the intermediate water outlet.

[0021] In one or some optional embodiments, the baffle may be in the shape of a cross structure.

[0022] As another aspect of an embodiment of the present invention, an embodiment of the present invention further provides a method for cyclone separation of oily wastewater, comprising:

[0023] The oily wastewater to be treated passes through the first bubble making device to form a bubble mixed liquid of the oily wastewater to be treated, and enters the first cyclone tangentially for primary cyclone flotation separation;

[0024] The oil droplets, bubbles, and oil droplet and bubble complexes separated from the primary separation are discharged from the overflow port, the clean water in the water phase after the primary separation is discharged through the clean water channel, and the intermediate water in the water phase after the primary separation is pressurized by a centrifugal pump and passed into the second bubble making device;

[0025] The reclaimed water passes through the second bubble making device to form a reclaimed water bubble mixture, and then enters the second cyclone tangentially for fine cyclone flotation separation;

[0026] The finely separated oil droplets, bubbles, and oil droplet and bubble complexes are discharged from the overflow port, the clean water in the finely separated water phase is discharged through the clean water channel, and the intermediate water in the finely separated water phase is pressurized by a centrifugal pump and passed into the second bubble making device.

[0027] In the oily wastewater cyclone separation device provided by the embodiment of the present invention, due to the provision of the first cyclone and the second cyclone, the oily wastewater is passed through the bubble making device to form a gas-water mixture, and enters the first cyclone tangentially. Under the action of centrifugal force and buoyancy, the water phase moves outward and downward, and the oil droplets and bubbles of larger particle size, and the oil droplets and bubble complexes all move inward and upward to be discharged, so as to achieve the separation of the larger particle size oil droplets in the oily wastewater, and complete the primary cyclone flotation separation; the downward moving water phase passes through the inner inverted cone and the outer inverted cone to form clean water and medium water, and the medium water contains smaller particle size oil droplets, and is pressurized by a centrifugal pump. After the bubble making device generates bubbles, it enters the second cyclone tangentially, so as to achieve the separation of the smaller particle size oil droplets, and complete the fine cyclone flotation separation. The oily wastewater cyclone separation device has a simple structure, and realizes the separation of the larger particle size oil droplets and the fine particle size oil droplets in the oily wastewater through the primary and fine cyclone flotation of the oily wastewater, thereby improving the oil-water separation efficiency and separation accuracy, and accelerating the oil-water separation speed.

[0028] The cyclone separation method for oily wastewater provided by the embodiment of the present invention is simple to operate. By primary and fine cyclone flotation of oily wastewater, the separation of larger oil droplets and fine oil droplets in the oily wastewater is achieved, thereby improving the cyclone separation treatment efficiency and separation accuracy of the oily wastewater and accelerating the oil-water separation speed. In addition, the method does not require the addition of chemical agents such as coagulants and flocculants, and has low operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of the oily wastewater cyclone separation device provided by an embodiment of the present invention;

[0030] In the figure: 1. separation cylinder, 11. overflow port, 12. outer inverted cone, 13. clean water channel, 2. first cyclone, 3. second cyclone, 4. first bubble making device, 5. second bubble making device, 6. inner inverted cone, 61. reclaimed water outlet, 7. centrifugal pump. DETAILED DESCRIPTION

[0031] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0032] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of the separation method of the oily wastewater cyclone separation device disclosed in the present disclosure as detailed in the attached claims.

[0033] The embodiment of the present invention provides a cyclone separation device for oily wastewater, referring to Figure 1 As shown, including:

[0034] Separation cylinder 1, cyclone assembly and bubble making assembly;

[0035] The cyclone assembly includes a first cyclone 2 and a second cyclone 3, wherein the first cyclone 2 is arranged at the lower part of the separation cylinder 1, and the second cyclone 3 is arranged at the upper part of the separation cylinder 1; the centrifugal force of the second cyclone 3 is greater than the centrifugal force of the first cyclone 3;

[0036] The upper end of the separation cylinder 1 is provided with an overflow port 11, and the lower end of the separation cylinder 1 is provided with an outer inverted cone 12;

[0037] An inner inverted cone 6 is provided inside the outer inverted cone 12. The inner inverted cone 6 is located below the first cyclone 2. A medium water outlet 61 is provided at the lower end of the inner inverted cone 6.

[0038] A water purification channel 13 is formed between the outer wall of the inner inverted cone 6 and the inner wall of the outer inverted cone 12;

[0039] The bubble making assembly comprises a first bubble making device 4, a second bubble making device 5 and a centrifugal pump 7;

[0040] The first bubble making device 4 is used to mix the oily wastewater to be treated with gas to form a bubble mixture of the oily wastewater to be treated, and make it tangentially enter the first cyclone 2;

[0041] The first cyclone 2 is used to separate the bubble mixture of the oily wastewater to be treated, so that the separated medium water is discharged from the medium water outlet 61 to the centrifugal pump 7 for pressurization, and the separated clean water is discharged through the clean water channel 13;

[0042] The second bubble making device 5 is used to mix the pressurized medium water with gas to form a medium water bubble mixed liquid, and make it tangentially enter the second cyclone 3;

[0043] The second cyclone is used to separate the introduced mixed liquid of gray water and bubbles, so that the separated gray water is discharged from the gray water outlet 61 to the centrifugal pump 7 for pressurization, and the separated clean water is discharged through the clean water channel 13.

[0044] In the oily wastewater cyclone separation device provided in the embodiment of the present invention, the liquid outlet of the first bubble making device 4 is connected to the tangential liquid inlet of the first cyclone 2, so that the bubble mixture of the oily wastewater to be treated formed by the first bubble making device 4 can enter the first cyclone 2 tangentially to perform primary cyclone flotation separation;

[0045] The liquid outlet of the second bubble making device 5 is connected to the tangential liquid inlet of the second cyclone 3; the inlet of the centrifugal pump 7 is connected to the medium water outlet 61 of the inner inverted cone 6, and the outlet of the centrifugal pump 7 is connected to the liquid inlet of the second bubble making device 5, so that the medium water obtained after the primary cyclone flotation separation of the bubble mixture of the oily wastewater to be treated by the first cyclone 2 is discharged from the medium water outlet 51, and the medium water bubble mixture formed by the second bubble making device 4 after being pressurized by the centrifugal pump 7 can enter the second cyclone 3 tangentially for fine cyclone flotation separation.

[0046] The specific structure of the first bubble making device 4 and the second bubble making device 5 described in the embodiment of the present invention can refer to the description of the relevant implementation method of the gas-liquid mixing equipment in the prior art. As long as it is possible to introduce the oily wastewater to be treated and the pressurized gas, so that highly dispersed tiny bubbles can be used as carriers to adhere to the pollutants in the oily wastewater, so that a large number of tiny bubbles are formed in the oily wastewater, and the pollutants are adhered to the bubbles and float to the water surface in a suspended state, so as to obtain a gas-liquid mixture of sewage and bubbles, no specific limitation is made in the embodiment of the present invention.

[0047] The specific structures of the first cyclone 2 and the second cyclone 3 described in the embodiment of the present invention can refer to the description of the relevant implementation methods of the cyclone separation equipment in the prior art. As long as the density difference between two or more phases can be used to separate the oil droplets, bubbles, oil droplets and bubble complexes in the gas-water mixture from the water phase under the action of centrifugal force, no specific limitation is made in the embodiment of the present invention.

[0048] In the embodiment of the present invention, since the oil droplet particle size in the bubble mixture of the oily wastewater to be treated formed in the first bubble producing device 4 is larger than the oil droplet particle size in the medium-water bubble mixture formed in the second bubble producing device 5, by setting the centrifugal force of the second cyclone 3 to be greater than the centrifugal force of the first cyclone 2, after the first cyclone 2 separates the oil droplets with larger particle sizes in the bubble mixture of the oily wastewater to be treated, the second cyclone 3 is used to separate the oil droplets with smaller particle sizes in the medium-water bubble mixture, thereby more accurately realizing the two-stage separation of the oily wastewater and achieving a good oil-water separation effect.

[0049] The specific arrangement of the first cyclone 2 and the second cyclone 3 in the separation cylinder 1 described in the embodiment of the present invention can refer to the description of the relevant technical solutions in the prior art, as long as the first cyclone 2 and the second cyclone 3 can be fixed, and the oil droplets, bubbles, and oil droplet and bubble complexes separated by the first cyclone 2 and the second cyclone 3 can be discharged through the overflow port 11, the clean water separated by the first cyclone 2 and the second cyclone 3 can be discharged through the clean water channel 13, and the reclaimed water still containing some oil separated by the first cyclone 2 and the second cyclone 3 can enter the centrifugal pump 7 through the reclaimed water outlet 61. In this regard, no specific limitation is made in the embodiment of the present invention.

[0050] In one embodiment, in the oily wastewater cyclone separation device provided by the embodiment of the present invention, the air inlet of the first bubble making device 4 is used to introduce gas of a first preset pressure; the liquid inlet of the first bubble making device 4 is used to introduce the oily wastewater to be treated at a set flow rate;

[0051] The first bubble making device 4 is used to mix the introduced oily wastewater to be treated and the gas at a first preset pressure to form a bubble mixture of the oily wastewater to be treated, and to allow the bubble mixture of the oily wastewater to be treated to enter the first cyclone 2 tangentially.

[0052] In one embodiment, in the oily wastewater cyclone separation device provided by the embodiment of the present invention, the air inlet of the second bubble making device 5 is used to introduce gas of a second preset pressure;

[0053] The second bubble making device 5 is used to mix the gas of the second preset pressure and the reclaimed water introduced by the centrifugal pump 7 to form a reclaimed water-bubble mixed liquid, and allow the reclaimed water-bubble mixed liquid to enter the second cyclone 3 tangentially.

[0054] In a specific embodiment, the centrifugal diameter of the second cyclone 3 may be smaller than the centrifugal diameter of the first cyclone 2 .

[0055] In the embodiment of the present invention, since the first cyclone 2 realizes the separation of oil droplets with larger particle sizes, the cyclone force can be relatively small. By increasing the centrifugal diameter, the volume of the gas-water mixture in the first cyclone 2 is increased, and the speed of oil-water separation is increased. The second cyclone 3 realizes the separation of oil droplets with smaller particle sizes. Therefore, the cyclone force of the cyclone is required to be higher. By reducing the centrifugal diameter, the oil-water separation capacity of the second cyclone 3 can be increased, and higher-precision oil-water separation can be achieved.

[0056] In one embodiment, in the oily wastewater cyclone separation device provided by the embodiment of the present invention, the number of the second cyclones 3 is multiple groups, the separation cylinder 1 is circular, and the multiple groups of second cyclones 3 are evenly arranged in the separation cylinder 1 along the circumferential direction.

[0057] In a specific embodiment, the number of the second cyclones 3 may be two or three groups.

[0058] In one embodiment, in the cyclone separation device for oily wastewater provided by the embodiment of the present invention, a baffle (not shown in the figure) is provided at the position of the intermediate water outlet 61 .

[0059] In the embodiment of the present invention, when the water phase obtained by oil-water separation is discharged from the inner inverted cone 6 through the intermediate water outlet 61, the intermediate water is prone to form a vortex in the pipeline between the inner inverted cone 6 and the centrifugal pump 7. In order to prevent the vortex, a baffle (not shown in the figure) can be set at the position of the intermediate water outlet 61, thereby reducing the kinetic energy of the water at the intermediate water outlet, playing a slow flow role, and eliminating the influence of the vortex.

[0060] In the embodiment of the present invention, the baffle can be set at a vertically downward position of the reclaimed water outlet. The specific setting method of the baffle can be determined according to actual usage conditions. In the embodiment of the present invention, no specific limitation is made to this.

[0061] In a specific embodiment, the baffle may be in a cross structure.

[0062] In order to better understand the specific implementation of the oily wastewater cyclone separation device provided in the embodiment of the present invention, the oil-water separation process of the oily wastewater is described below by using a specific example:

[0063] When the oily wastewater cyclone separation device provided in the embodiment of the present invention is used, the oily wastewater to be treated and the gas are firstly introduced into the first bubble making device 4 at a preset pressure and speed respectively, and the gas is dispersed in the oily wastewater in the first bubble making device 4 in the form of fine bubbles, and the particle size of the fine bubbles is close to the particle size of the dispersed phase oil droplets in the wastewater, so as to form a bubble mixture of the oily wastewater to be treated; then, the bubble mixture of the oily wastewater to be treated enters the first cyclone 2 along a tangential direction, and the speed of the bubble mixture of the oily wastewater to be treated entering the first cyclone 2 in a tangential direction is controlled by controlling the hydraulic pressure of the oily wastewater or the air intake flow rate of the gas of the bubble making device 4;

[0064] The first cyclone 2 performs primary cyclone flotation separation on the bubble mixture of the oily wastewater to be treated. Under the action of centrifugal force and buoyancy, the heavier water phase moves outward and downward, that is, moves downward along the inner wall of the separation tube 1. The water phase moving downward passes through the inner inverted cone 6 and the outer inverted cone 12 to form clean water and medium water; the lighter components such as oil droplets and bubbles all move inward and upward. During the migration of the lighter components, due to the density difference between the oil droplets and the tiny bubbles, the migration speed and floating speed of the microbubbles are faster, thereby increasing the chance of contact between the two. Through the continuous contact and adhesion of the two, oil droplets and bubble complexes are formed. The oil droplets, bubbles, and the complexes of oil droplets and bubbles rise to the upper part of the separation tube 1 under the action of buoyancy to form an oil collecting area. The oil droplets, bubbles, and the complexes of oil droplets and bubbles in the oil collecting area gradually and continuously rise under the action of pressure, and are finally discharged from the overflow port 11, so that the larger particle size oil droplets in the oily wastewater are separated and the primary cyclone flotation separation is completed;

[0065] Since the inner inverted cone 6 is provided inside the outer inverted cone 12, the separation of clean water and medium water is achieved through the inverted cone structure without affecting the cyclone. The medium water contains oil droplets with smaller particle sizes. The clean water is discharged from the clean water channel 13, and the medium water flows slowly through the baffle plate and enters the centrifugal pump 7. After the medium water is pressurized by the centrifugal pump 7, it is passed into the second bubble making device 5 at a preset pressure. Gas is also passed into the second bubble making device 5, so that in the second bubble making device 5, the gas is dispersed in the medium water containing oil droplets with smaller particle sizes in the form of fine bubbles. The particle size of the fine bubbles is close to that of the dispersed phase oil droplets in the sewage, forming a medium water bubble mixture. Then, the medium water bubble mixture enters the second cyclone 3 along the tangential direction. By controlling the hydraulic pressure of the medium water or the air intake flow rate of the gas passed into the second bubble making device 5, the speed of the medium water bubble mixture entering the second cyclone 3 tangentially can be controlled.

[0066] The second cyclone 3 performs fine cyclone flotation separation on the mixed liquid of water and bubbles. Under the action of centrifugal force and buoyancy, the heavier water phase moves outward and downward, that is, moves downward along the inner wall of the separation cylinder 1. The water phase moving downward passes through the inner inverted cone 6 and the outer inverted cone 12 to form clean water and medium water; the lighter components such as oil droplets and bubbles all move inward and upward. In the process of migration of the lighter components, due to the density difference between the oil droplets and the tiny bubbles, the migration speed and floating speed of the microbubbles are faster, thereby increasing the chance of contact between the two. Through the continuous contact and adhesion of the two, oil droplets and bubble complexes are formed. The oil droplets, bubbles, and the complex of oil droplets and bubbles rise to the oil collecting area at the top of the separation cylinder 1 under the action of buoyancy, gradually rise continuously under the action of pressure, and finally discharged from the overflow port 11. Since the centrifugal diameter of the second cyclone 3 is smaller than the centrifugal diameter of the first cyclone 2, the separation of smaller particle size oil droplets in the oily wastewater can be achieved, and the fine cyclone flotation separation can be completed.

[0067] In the embodiment of the present invention, the oil droplets, bubbles, and the composite of oil droplets and bubbles discharged from the overflow port 11 can be discharged into a specific oil collection container through a pipeline. The specific implementation method can refer to the relevant description in the prior art. In the embodiment of the present invention, no specific limitation is made to this.

[0068] In the embodiments of the present invention, referring to the following embodiments 1 and 2, in the process of using the above-mentioned oily wastewater cyclone separation device for oil-water separation, in order to ensure the effect of oil-water separation, the feed speed of the oily wastewater and the average particle size of the oil droplets, as well as the different centrifugal diameters and numbers of the first cyclone and the second cyclone, can be selected to appropriately select the feed speed of the oily wastewater and the gas intake flow rate, and the feed speed and the gas extraction flow rate can be adjusted to achieve the oil-water separation efficiency of the oily wastewater cyclone separation device.

[0069] Embodiment 1:

[0070] When the cyclone separation device for oily wastewater provided in an embodiment of the present invention adopts a cyclone separation cylinder 1 with a column diameter of 100 mm and a height of 1500 mm, the first cyclone has a diameter of 80 mm, and two second cyclones 3 with a diameter of 20 mm are built in it, the oily wastewater to be treated with an initial oil concentration of 502.6 mg / L and an average oil droplet particle size of d50=9.786 μm is fed into the separation cylinder 1 at a feeding rate of 450 mL / min. When the air intake flow rate is 900 mL / min, after cyclone flotation treatment, the oil concentration of the effluent obtained is 46.2 mg / L, the oil removal rate is 90.8%, and the average oil droplet particle size is d50=4.325 μm.

[0071] Embodiment 2:

[0072] When the cyclone separation device for oily wastewater provided in the embodiment of the present invention adopts a cyclone separation cylinder 1 with a column diameter of 500 mm and a height of 2000 mm, the first cyclone has a diameter of 400 mm, and three second cyclones 3 with a diameter of 80 mm are built in it, the oily wastewater to be treated with an initial oil concentration of 450.5 mg / L and an average oil droplet particle size of d50=9.259 μm is fed into the separation cylinder 1 at a feeding speed of 15 L / min, and the air intake flow rate is 25 L / min. After cyclone flotation treatment, the oil concentration in the effluent obtained is 49.8 mg / L, the oil removal rate is 88.9%, and the average oil droplet particle size is d50=5.058 μm.

[0073] In the oily wastewater cyclone separation device provided by the embodiment of the present invention, due to the provision of the first cyclone and the second cyclone, the oily wastewater is passed through the bubble making device to form a gas-water mixture, and enters the first cyclone tangentially. Under the action of centrifugal force and buoyancy, the water phase moves outward and downward, and the oil droplets and bubbles of larger particle size, and the oil droplets and bubble complexes all move inward and upward to be discharged, so as to achieve the separation of the larger particle size oil droplets in the oily wastewater, and complete the primary cyclone flotation separation; the downward moving water phase passes through the inner inverted cone and the outer inverted cone to form clean water and medium water, and the medium water contains smaller particle size oil droplets, and is pressurized by a centrifugal pump. After the bubble making device generates bubbles, it enters the second cyclone tangentially, so as to achieve the separation of the smaller particle size oil droplets, and complete the fine cyclone flotation separation. The oily wastewater cyclone separation device has a simple structure, and realizes the separation of the larger particle size oil droplets and the fine particle size oil droplets in the oily wastewater through the primary and fine cyclone flotation of the oily wastewater, thereby improving the oil-water separation efficiency and separation accuracy, and accelerating the oil-water separation speed.

[0074] Based on the same inventive concept, an embodiment of the present invention also provides a cyclone separation method for oily wastewater, which specifically includes the following steps:

[0075] The oily wastewater to be treated passes through the first bubble making device 4 to form a bubble mixture of the oily wastewater to be treated, and then enters the first cyclone 2 tangentially for primary cyclone flotation separation;

[0076] The oil droplets, bubbles, and oil droplet and bubble complexes separated from the primary separation are discharged from the overflow port 11, the clean water in the water phase after the primary separation is discharged through the clean water channel 13, and the intermediate water in the water phase after the primary separation is pressurized by the centrifugal pump 7 and then passed into the second bubble making device 5;

[0077] The medium water passes through the second bubble making device 5 to form a medium water bubble mixture, and then enters the second cyclone 3 tangentially for fine cyclone flotation separation;

[0078] The finely separated oil droplets, bubbles, and oil droplet and bubble complexes are discharged from the overflow port 11, the clean water in the finely separated water phase is discharged through the clean water channel 13, and the medium water in the finely separated water phase is pressurized by the centrifugal pump 7 and then passed into the second bubble making device 5.

[0079] The specific implementation process of the cyclone separation method for oily wastewater provided in the embodiment of the present invention can refer to the specific description of the cyclone separation device for oily wastewater in the above embodiment, which will not be repeated here.

[0080] The cyclone separation method for oily wastewater provided by the embodiment of the present invention is simple to operate. By primary and fine cyclone flotation of oily wastewater, the separation of larger oil droplets and fine oil droplets in the oily wastewater is achieved, thereby improving the cyclone separation treatment efficiency and separation accuracy of the oily wastewater and accelerating the oil-water separation speed. In addition, the method does not require the addition of chemical agents such as coagulants and flocculants, and has low operating costs.

[0081] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0082] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A cyclone separation device for oily wastewater, characterized in that: include: A separation cylinder (1), a cyclone component and a bubble making component; The cyclone assembly comprises a first cyclone (2) and a second cyclone (3) having a centrifugal force greater than that of the first cyclone (2), wherein the first cyclone (2) is arranged at the lower part of the separation cylinder (1), and the second cyclone (3) is arranged at the upper part of the separation cylinder (1); An overflow port (11) is provided at the upper end of the separation cylinder (1), an outer inverted cone (12) is provided at the lower end of the separation cylinder (1), an inner inverted cone (6) is provided inside the outer inverted cone (12), the inner inverted cone (6) is located below the first cyclone (2), and a medium water outlet (61) is provided at the lower end of the inner inverted cone (6); a clean water channel (13) is formed between the outer wall of the inner inverted cone (6) and the inner wall of the outer inverted cone (12); The bubble making assembly comprises a first bubble making device (4), a second bubble making device (5) and a centrifugal pump (7); The first bubble making device (4) is used to mix the oily wastewater to be treated with gas to form a bubble mixture of the oily wastewater to be treated, and the first cyclone (2) is used to separate the bubble mixture of the oily wastewater to be treated, so that the separated grey water is discharged from the grey water outlet (61) to the centrifugal pump (7) for pressurization; the second bubble making device (5) is used to mix the pressurized grey water with gas to form a grey water bubble mixture, and the second cyclone is used to separate the grey water bubble mixture.

2. The cyclone separation device for oily wastewater according to claim 1 is characterized in that: The liquid outlet of the first bubble making device (4) is connected to the tangential liquid inlet of the first cyclone (2); the liquid outlet of the second bubble making device (5) is connected to the tangential liquid inlet of the second cyclone (3); the inlet of the centrifugal pump (7) is connected to the middle water outlet (61) of the inner inverted cone (6), and the outlet of the centrifugal pump (7) is connected to the liquid inlet of the second bubble making device (5).

3. The cyclone separation device for oily wastewater according to claim 1, characterized in that: The air inlet of the first bubble making device (4) is used to introduce gas at a first preset pressure; the liquid inlet of the first bubble making device (4) is used to introduce oily wastewater to be treated at a set flow rate; The first bubble making device (4) is used to mix the introduced oily wastewater to be treated and the gas at a first preset pressure to form a bubble mixture of the oily wastewater to be treated, and to allow the bubble mixture of the oily wastewater to be treated to enter the first cyclone (2) tangentially.

4. The cyclone separation device for oily wastewater according to claim 1, characterized in that: The gas inlet of the second bubble-making device (5) is used to introduce gas of a second preset pressure; The second bubble making device (5) is used to mix the gas of the second preset pressure and the medium water introduced by the centrifugal pump (7) to form a medium water bubble mixture, and to allow the medium water bubble mixture to enter the second cyclone (3) tangentially.

5. The cyclone separation device for oily wastewater according to claim 1, characterized in that: The centrifugal diameter of the second cyclone (3) is smaller than the centrifugal diameter of the first cyclone (2).

6. The cyclone separation device for oily wastewater according to claim 1, characterized in that: The number of the second cyclones (3) is multiple, the separation cylinder (1) is circular, and the multiple groups of second cyclones (3) are evenly arranged in the separation cylinder (1) along the circumferential direction.

7. The cyclone separation device for oily wastewater according to claim 6, characterized in that: The number of the second cyclones (3) is two or three groups.

8. The cyclone separation device for oily wastewater according to any one of claims 1 to 7, characterized in that: A baffle is provided at the position of the intermediate water outlet (61).

9. The cyclone separation device for oily wastewater according to claim 8, characterized in that: The baffle is in a cross structure.

10. A method for cyclone separation of oily wastewater, using the cyclone separation device for oily wastewater according to any one of claims 1 to 9, characterized in that: include: The oily wastewater to be treated passes through a first bubble making device (4) to form a bubble mixture of the oily wastewater to be treated, and enters the first cyclone (2) tangentially for primary cyclone flotation separation; the first cyclone (2) performs primary cyclone flotation separation on the bubble mixture of the oily wastewater to be treated, and under the action of centrifugal force and buoyancy, the heavier water phase moves outward and downward, that is, moves downward along the inner wall of the separation cylinder (1), and the water phase moving downward passes through the inner inverted cone (6) and the outer inverted cone (12) to form clean water and medium water; the medium water contains oil droplets of smaller particle size; The oil droplets, bubbles, and oil droplet and bubble complexes obtained by primary separation are discharged from the overflow port (11), the clean water in the water phase after primary separation is discharged through the clean water channel (13), and the intermediate water in the water phase after primary separation is pressurized by a centrifugal pump (7) and then passed into the second bubble making device (5); The reclaimed water passes through the second bubble production device (5) to form a reclaimed water bubble mixture, and then enters the second cyclone (3) tangentially to perform fine cyclone flotation separation; The finely separated oil droplets, bubbles, and oil droplet and bubble complexes are discharged from the overflow port (11), the clean water in the finely separated water phase is discharged through the clean water channel, and the medium water in the finely separated water phase is pressurized by a centrifugal pump (7) and then passed into the second bubble making device (5).

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