Air floatation separation and decontamination system and method

Abstract

The application provides a gas floatation separation and dirt removal system and method, and relates to the technical field of sewage treatment.The system comprises a water tank, a gas floatation cyclone separation device, an intermittent air supply device and a circulating supply device.The water tank is used for storing oil-containing sewage, and the gas floatation cyclone separation device is connected with the water tank.The circulating supply device is used for extracting the sewage in the water tank and supplying the sewage to the gas floatation cyclone separation device, and the intermittent air supply device is used for supplying air to the gas floatation cyclone separation device.The gas floatation cyclone separation device can perform gas floatation separation treatment on the oil dirt in the sewage.The sewage after the gas floatation separation is discharged into the water tank again, and is extracted by the circulating supply device and supplied to the gas floatation cyclone separation device again, so that the circulating water supply of the gas floatation cyclone separation device is completed, and the gas floatation cyclone separation device can perform the gas floatation separation treatment on the sewage cyclically, thereby increasing the oil dirt treatment effect on the oil-containing sewage.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to an air flotation separation and removal system and method. Background Technology

[0002] Oily wastewater refers to wastewater containing oily substances generated during industrial production, transportation, and daily life. The sources of oily wastewater are very widespread, with petrochemical industries, catering, steel rolling, slaughtering, and dyeing industries, as well as municipal sewage discharge being particularly prevalent. When oily wastewater seeps into soil or water bodies, it forms an oil film that hinders the entry of air nutrients, leading to the death of plants and aquatic organisms and causing environmental pollution.

[0003] Currently, commonly used oil-water separation methods can be mainly divided into physical separation and chemical separation according to their separation properties. Physical separation methods not only have good separation effects, but are also simple to operate and environmentally friendly, and are therefore widely used. Among them, air flotation separation is a major physical separation method for separating oily wastewater. In the air flotation cyclone separation process, the oily wastewater is first introduced into a cyclone device to form a high-speed rotating cyclone field. In the cyclone field, air bubbles are injected into the cyclone field through a gas generating device. These air bubbles adhere to the surface of the oil, forming an air flotation effect. The presence of air bubbles reduces the density of oil and water particles, thereby promoting the separation of oil and water.

[0004] The invention disclosed in CN116924516B proposes an air flotation separation device for oily wastewater, mainly relating to the technical field of oil-water separation equipment. It includes a separation mechanism and an air flotation mechanism connected to the separation mechanism. The separation mechanism includes a separation tank, a drive rod perpendicularly passing through the separation tank along its axis, a separation filter screen sleeved on the drive rod and attached to the inner wall of the separation tank, and a drive motor located at the top of the separation tank. However, in actual air flotation separation treatment, the oil content in the discharged water is still relatively high after one air flotation separation process. To reduce the oil content in the water to meet the standard, it is necessary to repeatedly perform air flotation separation on the water produced by the air flotation separation device. The aforementioned air flotation separation device for oily wastewater cannot perform multiple air flotation separation processes on the wastewater. Therefore, this solution proposes an air flotation separation and decontamination device to solve the above problem. Summary of the Invention

[0005] In view of this, the present invention proposes an air flotation separation and decontamination system. Wastewater is drawn from a water tank via a circulating supply device and supplied to an air flotation cyclone separator. Simultaneously, air is supplied to the air flotation cyclone separator via an intermittent air supply device. The air flotation cyclone separator can perform air flotation separation of oil in the wastewater. The wastewater after air flotation separation is discharged back into the water tank and drawn out again by the circulating supply device and supplied to the air flotation cyclone separator, thus completing the circulating water supply to the air flotation cyclone separator. By setting up a circulating supply device, wastewater in the water tank can be drawn in a cyclical manner, allowing the air flotation cyclone separator to perform air flotation separation of wastewater in a cyclical manner, thereby increasing the treatment effect of oil in oily wastewater. By setting the air flotation cyclone separator to include multiple stages of air flotation mixing heads, each stage can generate a large number of bubbles when the wastewater flows through the multiple stages of air flotation mixing heads, thereby accelerating the treatment efficiency of oil in oily wastewater.

[0006] The technical solution of this invention is implemented as follows: This invention provides an air flotation separation and decontamination system, including a water tank, an air flotation cyclone separator, an intermittent air supply device, and a circulating air supply device, wherein...

[0007] The water tank is used to store oily wastewater. The air flotation cyclone separator is connected to the water tank, and the circulation supply device is connected to the water tank and the air flotation cyclone separator. The circulation supply device is used to supply the oily wastewater in the water tank to the air flotation cyclone separator.

[0008] The air flotation cyclone separator includes a multi-stage air flotation mixing head, and the multi-stage air flotation mixing head is connected in series with each other through multiple series pipes. The air flotation mixing head is used to mix oily wastewater with gas.

[0009] An intermittent air supply device is used to intermittently supply air to the air flotation mixing head.

[0010] Based on the above technical solutions, preferably, the number of multi-stage air flotation mixing heads is six, and the intermittent air supply device and the circulating supply device are both connected to the first-stage air flotation mixing head. The water tank is connected to the sixth-stage air flotation mixing head, and a first pressure reducing valve is provided between the second-stage and third-stage air flotation mixing heads, and another first pressure reducing valve is provided between the fourth-stage and fifth-stage air flotation mixing heads. The first pressure reducing valve is provided on the series pipe and is used to control the pressure of the dissolved air water flowing through the series pipe.

[0011] Based on the above technical solutions, preferably, the intermittent gas supply device includes a gas supply pipeline, a compressed gas cylinder, a second pressure reducing valve, and a relay, wherein,

[0012] The air supply pipeline is connected to the air flotation mixing head;

[0013] A compressed gas cylinder, connected to the gas supply line, is used to store compressed gas;

[0014] The second pressure reducing valve is located at the outlet of the compressed gas cylinder and is used to control the gas pressure entering the gas supply pipeline.

[0015] A relay is installed on the gas supply line between the compressed gas cylinder and the air flotation mixing head to control the on / off duration of the gas supply line.

[0016] Based on the above technical solutions, preferably, the gas pressure supplied to the air flotation mixing head by the gas supply pipeline is a, and the sewage pressure supplied to the air flotation mixing head by the circulating supply device is b, and the relationship between a and b is: 0.15MPa < a - b < 0.5MPa.

[0017] Based on the above technical solutions, preferably, the relay controls the gas supply pipeline to open one side every c seconds, and the gas supply pipeline supplies gas for d seconds each time, where the value range of c is 0.3 < c < 0.7, and the value range of d is 0.3 < d < 0.7.

[0018] Based on the above technical solutions, preferably, the air flotation mixing head includes an outer cylinder and an inner cylinder, wherein,

[0019] The inner cylinder is provided with multiple outer cylinders around its periphery, and the multiple outer cylinders are distributed at equal intervals. The outer cylinders are connected to the inner cylinder through a connecting pipe. The inner cylinder is provided with multiple water passage holes. Water discharged from the connecting pipe first passes through the multiple water passage holes before flowing into the interior of the inner cylinder, and the flow direction of the water discharged from the connecting pipe does not coincide with the central axis of the inner cylinder.

[0020] Based on the above technical solutions, the preferred embodiment further includes a ring-shaped water supply pipe, water supply branch pipes, a first connecting pipe, and a second connecting pipe, wherein...

[0021] A ring-shaped water supply pipe is provided on the outer side of multiple outer cylinders, and multiple water supply branch pipes are connected to the ring-shaped water supply pipe, with each of the multiple water supply branch pipes being connected to the multiple outer cylinders respectively;

[0022] The first connecting pipe is connected to the inner cylinder, and the second connecting pipe is connected to the ring-shaped water supply pipe.

[0023] Based on the above technical solutions, preferably, it also includes a water supply pipeline and a second control valve. The circulating supply device includes a circulating supply pipeline, a vertical multistage pump, and a first control valve, wherein...

[0024] A circulating supply pipeline is connected to the air flotation mixing head and the water tank mentioned in the first stage, and the circulating supply pipeline is connected to the bottom of the water tank;

[0025] A vertical multistage pump is installed on the circulating supply pipeline to draw water from the water tank and supply it to the air flotation mixing head.

[0026] The first control valve is installed on the circulating supply pipeline and is used to regulate the on / off state of the circulating supply pipeline;

[0027] The water supply pipeline is connected to the air flotation mixing head and the water tank of the sixth stage, and the water supply pipeline is connected to the top of the water tank;

[0028] The second control valve is installed on the water supply pipeline and is used to regulate the opening and closing of the water supply pipeline.

[0029] Based on the above technical solutions, preferably, it also includes two dosing devices, wherein...

[0030] Two dosing devices are connected to two series pipes respectively. One dosing device is used to add PAC to the series pipe between the third-stage air flotation mixing head and the fourth-stage air flotation mixing head, and the other dosing device is used to add PAM to the series pipe between the fourth-stage air flotation mixing head and the fifth-stage air flotation mixing head.

[0031] The present invention also proposes a flotation separation and decontamination method, including the above-mentioned flotation separation and decontamination system, and further including the following steps:

[0032] S1. Water is drawn from the water tank through a circulation supply device and supplied to the first-stage air flotation mixing head;

[0033] S2. Simultaneously open the intermittent air supply device to supply air to the first-stage air flotation mixing head, and control the intermittent air supply device to supply air once every c seconds, with each air supply time being d seconds;

[0034] S3. When the dissolved air water flows through the series pipe connecting the secondary air flotation mixing head and the tertiary air flotation mixing head, the pressure of the dissolved air water is reduced by the first pressure reducing valve.

[0035] S4. When the dissolved air water flows through the series pipe connecting the third-stage and fourth-stage air flotation mixing heads, PAC is added into the series pipe through a dosing device, and the concentration of the solution is controlled within the range of e, where e is in the range of 0 mg / L < e < 400 mg / L.

[0036] S5. When the dissolved air water flows through the series pipe connecting the fourth-stage air flotation mixing head and the fifth-stage air flotation mixing head, the pressure of the dissolved air water is reduced again through the first pressure reducing valve, and PAM is added into the series pipe through the dosing device, and the concentration of the drug solution is controlled to be f, where the value of f is: 0 mg / L < f < 120 mg / L.

[0037] S6. After the dissolved air water flows through the six-stage air flotation mixing head, it is discharged back into the water tank.

[0038] The air flotation separation and decontamination system and method of the present invention have the following advantages over the prior art:

[0039] (1) Wastewater is drawn from the water tank through a circulating supply device and supplied to the air flotation cyclone separator. Simultaneously, air is supplied to the air flotation cyclone separator through an intermittent air supply device. The air flotation cyclone separator can perform air flotation separation treatment on the oil in the wastewater. The wastewater after air flotation separation is discharged back into the water tank and drawn out again by the circulating supply device and supplied to the air flotation cyclone separator, thus completing the circulating water supply to the air flotation cyclone separator. By setting up a circulating supply device, wastewater in the water tank can be drawn out in a circulating manner, so that the air flotation cyclone separator can perform air flotation separation treatment on the wastewater in a circulating manner, thereby increasing the treatment effect on oil in oily wastewater. By setting up an air flotation cyclone separator including multiple stages of air flotation mixing heads, each stage can generate a large number of air bubbles when the wastewater flows through multiple stages of air flotation mixing heads, thereby accelerating the treatment efficiency of oil in oily wastewater.

[0040] (2) By setting up a dosing device between the third and fourth stage air flotation mixing heads and another dosing device between the fourth and fifth stage air flotation mixing heads, PAC and PAM are added respectively. After adding a certain concentration of PAC between the third and fourth stage air flotation mixing heads, it can be fully mixed at the fourth stage air flotation mixing head. When the mixed sewage flows to the fifth stage air flotation mixing head, PAM can form flocs after mixing with oil and fully mixing with air bubbles to form air-carried flocs, which can reduce the density of flocs and prolong the duration of air bubbles. The mixed liquid enters the sixth stage air flotation mixing head, where the flocs are stretched and extended, thus forming a floc capture net with a smaller density and larger area, which makes it easier to clean the oil in the oily sewage and increases the cleaning effect of oil. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the connection method of the air flotation separation and decontamination system of the present invention;

[0043] Figure 2 This is a three-dimensional schematic diagram of the air flotation mixing head of the air flotation separation and decontamination system of the present invention. Detailed Implementation

[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] like Figures 1-2 As shown, the air flotation separation and decontamination system of the present invention includes a water tank 1, an air flotation cyclone separator 2, an intermittent air supply device 3, and a circulating supply device 4. The water tank 1 is used to store oily wastewater. The air flotation cyclone separator 2 is connected to the water tank 1, and the circulating supply device 4 is connected to both the water tank 1 and the air flotation cyclone separator 2. The circulating supply device 4 is used to supply the oily wastewater in the water tank 1 to the air flotation cyclone separator 2. The air flotation cyclone separator 2 includes a multi-stage air flotation mixing head 21, which is connected in series with each other through multiple series pipes 22. The air flotation mixing head 21 is used to mix the oily wastewater with gas. The intermittent air supply device 3 is used to intermittently supply gas to the air flotation mixing head 21.

[0046] In practice, when treating oily wastewater in water tank 1, the wastewater is drawn from tank 1 by a circulating supply device 4 and supplied to the air flotation cyclone separator 2. Simultaneously, air is supplied to the air flotation cyclone separator 2 via an intermittent air supply device 3. During the passage of the wastewater through the air flotation cyclone separator 2, the air flotation cyclone separator 2 can perform air flotation separation of the oil in the wastewater. The separated wastewater is then discharged back into water tank 1 and drawn out again by the circulating supply device 4 and supplied to the air flotation cyclone separator 2, thus completing the circulating water supply to the air flotation cyclone separator 2. By setting up the circulating supply device 4, the wastewater in water tank 1 can be drawn in a cyclical manner, allowing the air flotation cyclone separator 2 to perform air flotation separation of the wastewater in a cyclical manner, thereby increasing the treatment effect of oil in oily wastewater. By setting up an air flotation cyclone separator 2, which includes multiple stages of air flotation mixing heads 21, each stage of the wastewater can generate a large number of bubbles as the wastewater flows through the multiple stages of air flotation mixing heads 21, thereby accelerating the treatment efficiency of oily wastewater.

[0047] In a preferred embodiment, the number of multi-stage air flotation mixing heads 21 is six, and the intermittent air supply device 3 and the circulating supply device 4 are both connected to the first-stage air flotation mixing head 21. The water tank 1 is connected to the sixth-stage air flotation mixing head 21, and a first pressure reducing valve 23 is provided between the second-stage air flotation mixing head 21 and the third-stage air flotation mixing head 21. Another first pressure reducing valve 23 is provided between the fourth-stage air flotation mixing head 21 and the fifth-stage air flotation mixing head 21. The first pressure reducing valve 23 is provided on the series pipe 22 and is used to control the pressure of dissolved air water flowing through the series pipe 22.

[0048] In practice, each of the multi-stage air flotation mixing heads 21 is equipped with a pressure gauge 6, and multiple pressure gauges 6 are used to monitor the pressure of dissolved air water inside each air flotation mixing head 21.

[0049] With this design, when the wastewater flows to the primary air flotation mixing head 21, the dissolved air water pressure is at its maximum due to the intermittent air supply device 3. The gas mixes with the wastewater through the primary air flotation mixing head 21, forming gas nuclei and generating a small number of microbubbles. When the dissolved air water flows naturally to the secondary air flotation mixing head 21, the dissolved air water pressure decreases slightly, releasing gas and generating microbubbles. Passing through the first pressure reducing valve 23 between the secondary and tertiary air flotation mixing heads 21, the pressure is further reduced, releasing more gas and forming a large number of microbubbles. Simultaneously, the release of bubbles is somewhat constrained by pressure in the tertiary and quaternary air flotation mixing heads 21. After the dissolved air water passes through the first pressure reducing valve 23 between the quaternary and quinary air flotation mixing heads 21, a large number of stable and uniform microbubbles are generated at the quinary air flotation mixing head 21. After passing through the sixth air flotation mixing head 21, the dissolved air water is discharged into the water tank 1 for reuse. By designing a multi-stage air flotation mixing head 21 to depressurize the dissolved air water one by one, the dissolved air water can generate a large number of bubbles, thereby increasing the cleaning efficiency of oily wastewater.

[0050] In a preferred embodiment, the intermittent gas supply device 3 includes a gas supply line 31, a compressed gas cylinder 32, a second pressure reducing valve 33, and a relay 34. The gas supply line 31 is connected to the air flotation mixing head 21. The compressed gas cylinder 32 is connected to the gas supply line 31 and is used to store compressed gas. The second pressure reducing valve 33 is located at the outlet of the compressed gas cylinder 32 and is used to control the gas pressure flowing into the gas supply line 31. The relay 34 is located on the gas supply line 31 between the compressed gas cylinder 32 and the air flotation mixing head 21 and is used to control the on / off duration of the gas supply line 31.

[0051] The gas pressure supplied by the gas supply pipeline 31 to the air flotation mixing head 21 is a, and the sewage pressure supplied by the circulating supply device 4 to the air flotation mixing head 21 is b. The relationship between a and b is: 0.15MPa < a - b < 0.5MPa.

[0052] Relay 34 controls the gas supply line 31 to open one side every c seconds, and the gas supply line 31 supplies gas for d seconds each time. The value range of c is 0.3 < c < 0.7, and the value range of d is 0.3 < d < 0.7.

[0053] This design controls the pressure difference between air and water pressure through the second pressure reducing valve 33, and controls the air supply duration and interval of the intermittent air supply device 3 through the relay 34, thereby increasing the separation effect of the air flotation cyclone separator 2 on oily wastewater.

[0054] If the pressure difference between a and b is less than 0.15 MPa, it will result in small bubbles, poor oil adsorption capacity, high energy consumption, and a high risk of equipment damage. If the pressure difference between a and b is greater than 0.5 MPa, it will result in large bubbles, insufficient buoyancy, low separation efficiency, and unstable operation.

[0055] If the value of c is too large, it will cause problems such as reduced bubble sealing, reduced separation efficiency and slow system response. If the value of c is too small, it will cause problems such as excessively high bubble density, increased bubble bursting and increased energy consumption.

[0056] If the value of d is too large, problems such as excessively large bubbles, uneven buoyancy, and fluctuating separation effect will occur. If the value of d is too small, problems such as excessively small bubbles, excessively high bubble density, and poor system stability will occur.

[0057] In a preferred embodiment, the air flotation mixing head 21 includes an outer cylinder 211 and an inner cylinder 212. Multiple outer cylinders 211 are arranged around the inner cylinder 212 and are equidistantly distributed. The outer cylinders 211 are connected to the inner cylinder 212 through a connecting pipe 213. Multiple water passage holes are provided on the inner cylinder 212. Water discharged from the connecting pipe 213 first passes through the multiple water passage holes and then flows into the interior of the inner cylinder 212. The flow direction of the water discharged from the connecting pipe 213 does not coincide with the central axis of the inner cylinder 212.

[0058] It includes a ring-shaped water supply pipe 214, water supply branch pipes 215, a first connecting pipe 216, and a second connecting pipe 217. The ring-shaped water supply pipe 214 is located on the outside of multiple outer cylinders 211, and multiple water supply branch pipes 215 are connected to the ring-shaped water supply pipe 214. The multiple water supply branch pipes 215 are respectively connected to multiple outer cylinders 211. The first connecting pipe 216 is connected to the inner cylinder 212, and the second connecting pipe 217 is connected to the ring-shaped water supply pipe 214.

[0059] In practice, dissolved air water flows through the second connecting pipe 217 and the first connecting pipe 216 to the interior of the annular water supply pipe 214, through the water supply branch pipe 215 to the interior of each outer cylinder 211, and through the connecting pipe 213 to the interior of the inner cylinder 212, generating a swirling flow field for air flotation separation reaction. The reacted dissolved air water is discharged from the bottom of the inner cylinder 212 into the interior of the first connecting pipe 216, and then flows through the first connecting pipe 216 to the interior of the next-stage air flotation mixing head 21. By setting the flow direction of the water discharged from the connecting pipe 213 to not coincide with the central axis of the inner cylinder 212, the water discharged from the connecting pipe 213 can flow tangentially into the interior of the inner cylinder 212, thereby promoting the formation of a swirling flow field inside the inner cylinder 212. By setting the dissolved air water to pass through multiple water passages before being discharged into the interior of the inner cylinder 212, the dissolved air water can be depressurized under the obstruction of the water passage walls, generating bubbles.

[0060] In a preferred embodiment, the device further includes a water supply pipeline 51 and a second control valve 52. The circulating supply device 4 includes a circulating supply pipeline 41, a vertical multistage pump 42, and a first control valve 43. The circulating supply pipeline 41 is connected to the first-stage air flotation mixing head 21 and the water tank 1, and the circulating supply pipeline 41 extends to the bottom of the water tank 1. The vertical multistage pump 42 is installed on the circulating supply pipeline 41 and is used to draw water from the water tank 1 and supply it to the air flotation mixing head 21. The first control valve 43 is installed on the circulating supply pipeline 41 and is used to regulate the opening and closing of the circulating supply pipeline 41. The water supply pipeline 51 is connected to the sixth-stage air flotation mixing head 21 and the water tank 1, and the water supply pipeline 51 extends to the top of the water tank 1. The second control valve 52 is installed on the water supply pipeline 51 and is used to regulate the opening and closing of the water supply pipeline 51.

[0061] In practice, after being drawn from the water tank 1 by the vertical multistage pump 42, the water is supplied to the first-stage air flotation mixing head 21 through the circulation supply pipeline 41. After multistage air flotation separation by the air flotation cyclone separator 2, the water is discharged into the interior of the water tank 1 through the water supply pipeline 51, forming a loop. During the reaction, the circulation supply pipeline 41 can be opened and closed by the first control valve 43, and the water supply pipeline 51 can be opened and closed by the second control valve 52.

[0062] In a preferred embodiment, two dosing devices are also included, wherein the two dosing devices are respectively connected to two series pipes 22. One dosing device is used to add PAC to the series pipe 22 between the third-stage air flotation mixing head 21 and the fourth-stage air flotation mixing head 21, and the other dosing device is used to add PAM to the series pipe 22 between the fourth-stage air flotation mixing head 21 and the fifth-stage air flotation mixing head 21.

[0063] By installing a dosing device between the third-stage and fourth-stage air flotation mixing heads 21 for adding PAC, and another dosing device between the fourth-stage and fifth-stage air flotation mixing heads 21 for adding PAM, the concentration of added PAC is controlled within the range of 0-400 mg / L, and the concentration of added PAM is controlled within the range of 0-120 mg / L. Specifically, under the action of the first pressure reducing valve 23, a large number of bubbles are generated when the wastewater flows through the third-stage air flotation mixing head 21. After adding a certain concentration of PAC between the third-stage and fourth-stage air flotation mixing heads 21, a large amount of gas bubbles are generated at the fourth-stage air flotation mixing head 21. The bubbles can be fully mixed with PAC. When the mixed wastewater flows to the fifth-stage air flotation mixing head 21, the first pressure reducing valve 23 located between the fourth and fifth-stage air flotation mixing heads 21 can reduce the pressure again, thereby forming stable and uniform microbubbles. At the same time, a certain concentration of PAM is added. At this time, PAM can form flocs after mixing with oil, and after being fully mixed with bubbles, it forms air-carried flocs, which can reduce the density of flocs and prolong the duration of bubbles. The mixed liquid enters the sixth-stage air flotation mixing head 21. The flocs are stretched and extended at the sixth-stage air flotation mixing head 21, thereby forming a floc capture net with a smaller density and a larger area, which makes it easier to clean the oil in the oily wastewater and increases the cleaning effect of oil.

[0064] The present invention also proposes a flotation separation and decontamination method, including the above-mentioned flotation separation and decontamination system, and further including the following steps:

[0065] Step 1: Water is drawn from water tank 1 by circulation supply device 4 and supplied to primary air flotation mixing head 21;

[0066] Step 2: Simultaneously turn on the intermittent air supply device 3 to supply air to the first-stage air flotation mixing head 21, and control the intermittent air supply device 3 to supply air once every c seconds, and each air supply time is d seconds;

[0067] Step 3: When the dissolved air water flows through the series pipe 22 connecting the secondary air flotation mixing head 21 and the tertiary air flotation mixing head 21, the pressure of the dissolved air water is reduced by the first pressure reducing valve 23;

[0068] Step 4: As the dissolved air water flows through the series pipe 22 connecting the third-stage flotation mixing head 21 and the fourth-stage flotation mixing head 21, PAC is added into the series pipe 22 through the dosing device, and the concentration of the chemical solution is controlled within the range of e, where e is in the range of 0 mg / L < e < 400 mg / L.

[0069] Step 5: When the dissolved air water flows through the series pipe 22 connecting the fourth-stage air flotation mixing head 21 and the fifth-stage air flotation mixing head 21, the pressure of the dissolved air water is reduced again through the first pressure reducing valve 23, and PAM is added into the series pipe 22 through the dosing device, and the concentration of the drug is controlled to be f, where the value of f is: 0 mg / L < f < 120 mg / L.

[0070] Step 6: After the dissolved air water flows through the six-stage air flotation mixing head 21, it is discharged back into the interior of the water tank 1.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for air flotation separation and pollution removal, characterized in that, A flotation separation and decontamination system is based on an air flotation system, the system comprising a water tank (1), an air flotation cyclone separator (2), an intermittent air supply device (3), and a circulating air supply device (4), wherein, The water tank (1) is used to store oily wastewater. The air flotation cyclone separator (2) is connected to the water tank (1), and the circulation supply device (4) is connected to the water tank (1) and the air flotation cyclone separator (2). The circulation supply device (4) is used to supply the oily wastewater in the water tank (1) to the air flotation cyclone separator (2). The air flotation cyclone separator (2) includes a multi-stage air flotation mixing head (21), and the multi-stage air flotation mixing head (21) is connected in series with each other through multiple series pipes (22). The air flotation mixing head (21) is used to mix oily wastewater with gas. Intermittent gas supply device (3) for intermittently supplying gas to the air flotation mixing head (21); The intermittent gas supply device (3) includes a gas supply pipeline (31), a compressed gas cylinder (32), a second pressure reducing valve (33), and a relay (34). The air flotation mixing head (21) includes an outer cylinder (211) and an inner cylinder (212), wherein, The inner cylinder (212) is provided with a plurality of outer cylinders (211) around its periphery, and the plurality of outer cylinders (211) are equidistantly distributed. The outer cylinders (211) are connected to the inner cylinder (212) through a connecting pipe (213). The inner cylinder (212) is provided with a plurality of water passage holes. Water discharged from the connecting pipe (213) first passes through the plurality of water passage holes and then flows into the interior of the inner cylinder (212). The flow direction of the water discharged from the connecting pipe (213) does not coincide with the central axis of the inner cylinder (212). The method includes the following steps: S1. Water is drawn from the water tank (1) by the circulating supply device (4) and supplied to the first-stage air flotation mixing head (21). S2. Simultaneously open the intermittent gas supply device (3) to supply gas to the first-stage air flotation mixing head (21), and control the intermittent gas supply device (3) to supply gas once every c seconds, and each gas supply time is d seconds; S3. When dissolved air water flows through the series pipe (22) connecting the secondary air flotation mixing head (21) and the tertiary air flotation mixing head (21), the pressure of dissolved air water is reduced by the first pressure reducing valve (23). S4. When the dissolved air water flows through the series pipe (22) connecting the third-stage air flotation mixing head (21) and the fourth-stage air flotation mixing head (21), PAC is added into the series pipe (22) through the dosing device, and the concentration of the drug solution is controlled within the range of e, where the value of e is: 0 mg / L < e < 400 mg / L. S5. When the dissolved air water flows through the series pipe (22) connecting the fourth-stage air flotation mixing head (21) and the fifth-stage air flotation mixing head (21), the pressure of the dissolved air water is reduced again through the first pressure reducing valve (23), and PAM is added into the series pipe (22) through the dosing device, and the concentration of the drug is controlled to be f, where the value of f is: 0 mg / L < f < 120 mg / L; S6. After the dissolved air water flows through the six-stage air flotation mixing head (21), it is discharged back into the interior of the water tank (1); The gas pressure supplied by the gas supply pipeline (31) to the air flotation mixing head (21) is a, and the sewage pressure supplied by the circulating supply device (4) to the air flotation mixing head (21) is b. The relationship between a and b is: 0.15MPa < a - b < 0.5MPa. The relay (34) controls the gas supply line (31) to open one side every c seconds, and the gas supply line (31) supplies gas for d seconds each time. The value range of c is 0.3 < c < 0.7, and the value range of d is 0.3 < d < 0.

7.

2. The air flotation separation and decontamination method as described in claim 1, characterized in that, The number of multi-stage air flotation mixing heads (21) is six, and the intermittent air supply device (3) and the circulating supply device (4) are both connected to the first-stage air flotation mixing head (21). The water tank (1) is connected to the sixth-stage air flotation mixing head (21). A first pressure reducing valve (23) is provided between the second-stage air flotation mixing head (21) and the third-stage air flotation mixing head (21). Another first pressure reducing valve (23) is provided between the fourth-stage air flotation mixing head (21) and the fifth-stage air flotation mixing head (21). The first pressure reducing valve (23) is provided on the series pipe (22) and is used to control the pressure of dissolved air water flowing through the series pipe (22).

3. The air flotation separation and decontamination method as described in claim 2, characterized in that, The gas supply line (31) is connected to the air flotation mixing head (21); the compressed gas cylinder (32) is connected to the gas supply line (31) and is used to store compressed gas; the second pressure reducing valve (33) is set at the outlet of the compressed gas cylinder (32) and is used to control the gas pressure flowing into the gas supply line (31); the relay (34) is set on the gas supply line (31) between the compressed gas cylinder (32) and the air flotation mixing head (21) and is used to control the on / off time of the gas supply line (31).

4. The air flotation separation and decontamination method as described in claim 1, characterized in that, It also includes a ring-shaped water supply pipe (214), a water supply branch pipe (215), a first connecting pipe (216), and a second connecting pipe (217), among which, A ring-shaped water supply pipe (214) is provided on the outside of multiple outer cylinders (211), and multiple water supply branch pipes (215) are connected to the ring-shaped water supply pipe (214), and the multiple water supply branch pipes (215) are respectively connected to the multiple outer cylinders (211); The first connecting pipe (216) is connected to the inner cylinder (212), and the second connecting pipe (217) is connected to the annular water supply pipe (214).

5. The air flotation separation and decontamination method as described in claim 2, characterized in that, It also includes a water supply pipeline (51) and a second control valve (52). The circulating supply device (4) includes a circulating supply pipeline (41), a vertical multistage pump (42), and a first control valve (43). The circulating supply pipeline (41) is connected to the first-stage air flotation mixing head (21) and the water tank (1), and the circulating supply pipeline (41) is connected to the bottom of the water tank (1); A vertical multistage pump (42) is installed on the circulating supply pipeline (41) to draw water from the water tank (1) and supply it to the air flotation mixing head (21). The first control valve (43) is installed on the circulating supply pipeline (41) and is used to regulate the opening and closing of the circulating supply pipeline (41); The water supply pipeline (51) is connected to the air flotation mixing head (21) and the water tank (1) of the sixth stage, and the water supply pipeline (51) is connected to the top of the water tank (1); The second control valve (52) is installed on the water supply pipeline (51) and is used to regulate the opening and closing of the water supply pipeline (51).

6. The air flotation separation and decontamination method as described in claim 1, characterized in that, It also includes two dosing devices, among which, Two dosing devices are connected to two series pipes (22), one of which is used to add PAC to the series pipe (22) between the third-stage air flotation mixing head (21) and the fourth-stage air flotation mixing head (21), and the other dosing device is used to add PAM to the series pipe (22) between the fourth-stage air flotation mixing head (21) and the fifth-stage air flotation mixing head (21).

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