Air flotation machine for biogas slurry

Abstract

The utility model discloses an air floatation machine for biogas slurry, which belongs to the field of air floatation machines and comprises a pretreatment tank, a water inlet is arranged at the top of one side of the pretreatment tank, a stirring device is arranged in the pretreatment tank, and an air floatation tank and a clean water tank are sequentially arranged on the other side of the pretreatment tank. The front end of a water inlet of the air floatation tank is provided with a double-layer dissolved air release device with different flows, the double-layer dissolved air release device with different flows is connected with an air dissolving tank, one side of the air dissolving tank is provided with an air compressor, a slag scraper and a scum tank are arranged above the air floatation tank, and the bottom of the air floatation tank is provided with a water collecting pipe and a micro-nano aeration device. A water outlet is formed in the top of the clean water tank. Double-layer dissolved air release devices with different flows are arranged in front of the air floatation tank, and the high SS characteristic of biogas slurry is adapted through the flow difference between the upper layer and the lower layer, so that the floating efficiency of particles is improved; a micro-nano aeration device is arranged in the air floatation tank, so that particle precipitation caused by bubble breakage during slag scraping is prevented; the structure is simple, complex control is not needed, and maintenance and popularization are easy.

Description

Technical Field

[0001] This utility model relates to the field of flotation machines, and more particularly to a flotation machine for biogas slurry. Background Technology

[0002] Biogas slurry, a common byproduct of agricultural or industrial wastewater treatment, is difficult to treat due to its high concentration of suspended solids (SS). Air flotation is one technology for treating biogas slurry. Its principle involves releasing tiny air bubbles that combine with solid particles in the biogas slurry, using buoyancy to carry the particles to the surface, where they are then removed by a scraper.

[0003] Currently, traditional dissolved air flotation (DAF) devices for treating biogas slurry typically use a single-flow dissolved air release unit, which is difficult to adapt to the characteristics of high-suspended solids (SS) particles in biogas slurry. This results in insufficient bonding between bubbles and particles, leading to low flotation efficiency. Furthermore, the scum scraper can disturb the surface bubbles during scum removal, causing them to burst. This causes previously floating solid particles to lose buoyancy and re-settle, affecting the treatment effect. Micro-nano bubbles can re-float settled particles, stabilizing the biogas slurry entering the collection pipe below. Simultaneously, they can activate nutrients and reduce pollutants. Utility Model Content

[0004] The purpose of this invention is to provide a flotation machine for biogas slurry, which solves the problems of traditional flotation devices having fixed positions and single flow rates, making it impossible to optimize bubble release efficiency for the high SS characteristics of biogas slurry, resulting in insufficient particle floating; and bubbles easily breaking during sludge scraping by the scraper, causing solid particles to settle; and the biogas slurry having low clarity and high load for subsequent treatment.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] This utility model discloses a flotation machine for biogas slurry, comprising a pretreatment tank, an inlet located at the top of one side of the pretreatment tank, a stirring device located near the inlet inside the pretreatment tank, a flotation tank and a clear water tank located sequentially on the other side of the pretreatment tank, a double-layer dissolved gas release device with different flow rates located in the pretreatment tank and at the front end of the inlet of the flotation tank, the double-layer dissolved gas release device with different flow rates connected to a dissolved gas tank, an air compressor located on one side of the dissolved gas tank, a sludge scraper located above the flotation tank, a scum trough located on the sludge discharge side of the sludge scraper, a water collection pipe located at the bottom of the flotation tank for transporting clarified biogas slurry to the clear water tank, a micro-nano aeration device located at the bottom of the flotation tank, and an outlet located at the top of the clear water tank on the side away from the flotation tank.

[0007] Furthermore, the stirring device includes a housing with an opening at the bottom, a stirrer is disposed inside the housing, and a motor for driving the stirrer to rotate is disposed on the top surface of the housing.

[0008] Furthermore, the dual-layer dissolved gas release device with different flow rates includes upper and lower release structures, and the dissolved gas water flow rate of each layer can be independently adjusted.

[0009] Furthermore, the lower release structure includes a lower release box, and a plurality of lower release tubes are provided on the side wall of the lower release box. The upper release structure includes an upper release box, and a plurality of upper release tubes are provided on the outer wall of the upper release box. The number of lower release tubes is greater than the number of upper release tubes. A conveying pipe is provided at the center of the lower release box and the upper release box, and the conveying pipe is connected to the dissolved gas tank.

[0010] Furthermore, the dissolved gas tank is equipped with a pressure gauge for monitoring the pressure inside the tank, and the bottom of the dissolved gas tank is equipped with an outlet for discharging excess gas from inside the tank.

[0011] Furthermore, the dissolved gas tank is connected to the clear water tank via a pipeline.

[0012] Furthermore, the micro-nano aeration device includes several aeration pipes arranged in parallel.

[0013] Furthermore, the aeration time of the micro-nano aeration device is set according to the single-cycle running time of the slag scraper, and the aeration time of the micro-nano aeration device is set to 1 / 3 to 1 / 2 of the single-cycle running time of the slag scraper.

[0014] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0015] This invention features a dual-layer dissolved air release device with different flow rates at the front of the flotation tank. By adapting the high suspended solids (SS) characteristics of the biogas slurry to the difference in flow rates between the upper and lower layers, the flotation efficiency of solid particles in the biogas slurry is improved. A micro-nano aeration device is installed inside the flotation tank to prevent particle sedimentation caused by the bursting of air bubbles during sludge scraping. It can also activate the nutrients in the biogas slurry, thereby improving the treatment effect. This invention has a simple structure, requires no complex control, and is easy to maintain and promote. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings.

[0017] Figure 1 This is a front view of the flotation machine for biogas slurry according to this utility model;

[0018] Figure 2 This is a schematic diagram of the structure of the double-layer dissolved gas release device with different flow rates of this utility model;

[0019] Figure 3 This is a schematic diagram of the lower layer release structure of this utility model;

[0020] Figure 4 This is a schematic diagram of the upper release structure of this utility model;

[0021] Figure 5 This is a schematic diagram of the overall structure of the air flotation tank and clear water tank of this utility model;

[0022] Figure 6 This is a top view of the slag scraper of this utility model.

[0023] Explanation of reference numerals in the attached diagram: 1. Inlet; 2. Motor; 3. Agitator; 4. Double-layer dissolved air release device with different flow rates; 401. Conveying pipe; 402. Lower release box; 403. Lower release pipe; 404. Upper release box; 405. Upper release pipe; 5. Dissolved air tank; 6. Sludge scraper; 601. Drive shaft; 602. Driven shaft; 603. Sludge scraper; 604. Sludge scraper bracket; 605. Chain; 7. Flotation tank; 8. Scum trough; 9. Water collection pipe; 10. Micro-nano aeration device; 11. Clear water tank; 12. Outlet; 13. Air compressor; 14. Pressure gauge; 15. Air outlet; 16. Pretreatment tank; 17. Outer shell. Detailed Implementation

[0024] like Figure 1-6As shown, a flotation machine for biogas slurry includes a pretreatment tank 16. An inlet 1 is connected to the top of one side of the pretreatment tank 16. A stirring device is installed inside the pretreatment tank 16 near the inlet 1. A flotation tank 7 and a clear water tank 11 are sequentially arranged on the other side of the pretreatment tank 16. A double-layer dissolved air release device 4 with different flow rates is installed inside the pretreatment tank 16 and at the front end of the inlet of the flotation tank 7. The double-layer dissolved air release device 4 with different flow rates is connected to a dissolved air tank 5. A pressure gauge 14 is installed on the dissolved air tank 5 to monitor the pressure inside the tank. An outlet 15 is installed at the bottom of the dissolved air tank 5 to discharge excess gas and maintain stable pressure inside the tank. The dissolved air tank 5 stores dissolved air water. The pressure gauge 14 monitors the pressure inside the tank to provide a stable source of dissolved air for the dissolved air release device. The function of the dissolved air tank 5 is to dissolve air in water to form high-pressure dissolved air water, providing a basis for subsequent bubble release. One side of the dissolved air tank 5 is connected to... An air compressor 13 is connected to the dissolved air tank 5, providing compressed air to ensure the air supply for the dissolved air process. By controlling the air input, the dissolved air tank 5 forms dissolved water that meets the requirements. A scum scraper 6 is installed above the flotation tank 7, and a scum trough 8 is provided on the scum discharge side of the scum scraper 6. The scum scraper 6 is driven by a drive device, and its scraper blades contact the water surface of the flotation tank 7. During operation, it pushes the scum on the water surface to the scum trough 8, and the scum is discharged from the flotation tank 7 through the scum trough 8. Located at the edge of the flotation tank 7, and working in conjunction with the sludge scraper 6, it is used to collect the scum scraped off by the sludge scraper 6. The scum can be discharged through the sludge discharge port at the bottom of the tank for subsequent treatment. The bottom of the flotation tank 7 is equipped with a water collection pipe 9 for transporting the clarified biogas slurry to the clear water tank 11. The bottom of the flotation tank 7 is equipped with a micro-nano aeration device 10. The top of the clear water tank 11 on the side away from the flotation tank 7 is equipped with a water outlet 12. The clear water tank 11 is used to temporarily store the clarified biogas slurry after flotation treatment.

[0025] Specifically, the water collection pipe 9 is horizontally arranged at the bottom of the flotation tank 7 and connected to the clear water tank 11. The pipe body is provided with multiple water collection holes, which can evenly collect the treated clarified biogas slurry and transport it to the clear water tank 11.

[0026] The stirring device includes a shell 17 with an opening at the bottom. A stirrer 3 is installed inside the shell 17. A motor 2 for driving the stirrer 3 to rotate is installed on the top surface of the shell 17. In use, the motor 2 drives the stirrer 3 to rotate, preventing solid particles in the biogas slurry from settling and accumulating at the bottom of the pretreatment tank 16.

[0027] The dual-layer dissolved gas release device 4 with different flow rates includes upper and lower release structures, each of which can independently adjust the dissolved gas water flow rate (e.g., the upper layer flow rate is Q1, the lower layer flow rate is Q2, Q1≠Q2). The lower release structure includes a lower release box 402, and a plurality of lower release pipes 403 are provided on the side wall of the lower release box 402. The upper release structure includes an upper release box 404, and a plurality of upper release pipes 405 are provided on the outer wall of the upper release box 404. The number of lower release pipes 403 is greater than the number of upper release pipes 405. A conveying pipe 401 is provided at the center of the lower release box 402 and the upper release box 404, and the conveying pipe 401 is connected to the dissolved gas tank 5.

[0028] For high SS biogas slurry, compared with traditional single flow devices, the dual-layer dissolved air release device with different flow rates can be specifically combined with particles of different sizes, thus improving the flotation efficiency.

[0029] The dissolved air tank 5 is connected to the clear water tank 11 via a pipeline, and a valve is installed on the pipeline. The clarified water in the clear water tank 11 can be partially returned to the dissolved air tank 5 as a source of dissolved air water, thereby improving the water resource utilization rate.

[0030] Slag scraper 6 is a chain scraper; such as Figure 6 As shown, the slag scraper 6 includes a drive shaft 601 and a driven shaft 602. Drive sprockets are installed near both ends of the drive shaft 601, and driven sprockets are installed near both ends of the driven shaft 602. The drive and driven sprockets are connected by a chain 605. Scraper supports 604 are mounted on two parallel chains 605, and scraper plates 603 are mounted on the scraper supports 604. The drive shaft 601 is connected to a drive motor and a reducer. During operation, the scraper plates 603 flip onto the water surface at the inlet end of the flotation tank 7 and move slowly and uniformly towards the slag trough 8 under the drive of the chains 605, pushing the slag on the water surface into the slag trough 8.

[0031] The micro-nano aeration device 10 includes several aeration pipes arranged in parallel. The aeration time is set according to the single-cycle running time of the slag scraper 6. The aeration time of the micro-nano aeration device 10 is set to 1 / 3 to 1 / 2 of the single-cycle running time of the slag scraper 6. For example, when the time for one cycle of the slag scraper 6 is 15 minutes, the aeration time can be set to 5 to 8 minutes to ensure continuous bubble replenishment during the critical stage from the initial stage of scum formation to the near end of the slag scraper 6, so as to prevent the bubbles from bursting and the particles from sinking.

[0032] The working process of this utility model is as follows:

[0033] The biogas slurry enters the pretreatment tank 16 through the inlet 1. The stirrer 3 driven by the motor 2 stirs the biogas slurry to prevent suspended solids in the biogas slurry from settling and accumulating at the bottom of the contact area. At the same time, the air compressor 13 pressurizes air into the dissolved gas tank 5. The dissolved gas water in the dissolved gas tank 5 is transported to the double-layer dissolved gas release device 4 with different flow rates under pressure. The upper and lower layers of the device release dissolved gas water at different flow rates (Q1 and Q2, Q1≠Q2), generating a large number of micro bubbles. The bubbles fully combine with the solid particles in the biogas slurry.

[0034] During the process of solid particles being carried to the surface by bubbles, the biogas slurry then enters the flotation tank 7. The micro-nano aeration device 10 at the bottom of the flotation tank 7 performs aeration. The aeration time is set according to the single-cycle running time of the sludge scraper 6 to continuously replenish micro bubbles and enhance the bonding stability between bubbles and particles.

[0035] When solid particles are carried to the surface of the flotation tank 7 and form scum, the scum scraper 6 moves back and forth along the length of the tank to scrape the scum into the scum trough 8 and discharge it.

[0036] The treated clarified biogas slurry is collected through the water collection pipe 9 and flows into the clear water tank 11 for temporary storage. Part of the clarified water can be returned to the dissolved gas tank 5 as a dissolved gas water source, and the rest is discharged through the outlet 12. Throughout the process, the pressure in the dissolved gas tank 5 is monitored by the pressure gauge 14 to ensure stable operation of the device. Excess gas in the dissolved gas tank 5 is discharged through the gas outlet 15.

[0037] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A flotation machine for biogas slurry, characterized in that: The system includes a pretreatment tank (16), with an inlet (1) at the top of one side. A stirring device is located inside the pretreatment tank (16) near the inlet (1). A flotation tank (7) and a clear water tank (11) are sequentially arranged on the other side of the pretreatment tank (16). A double-layer dissolved air release device (4) with different flow rates is located inside the pretreatment tank (16) and at the front end of the inlet of the flotation tank (7). The double-layer dissolved air release device (4) with different flow rates is connected to the dissolved air tank (…). 5) Connection: An air compressor (13) is provided on one side of the dissolved air tank (5), a slag scraper (6) is provided above the flotation tank (7), a slag trough (8) is provided on the slag discharge side of the slag scraper (6), a water collection pipe (9) for transporting clarified biogas slurry to the clear water tank (11) is provided at the bottom of the flotation tank (7), a micro-nano aeration device (10) is provided at the bottom of the flotation tank (7), and an outlet (12) is provided on the top of the side of the clear water tank (11) away from the flotation tank (7).

2. The flotation machine for biogas slurry according to claim 1, characterized in that: The stirring device includes a shell (17) with a bottom opening, a stirrer (3) is provided inside the shell (17), and a motor (2) for driving the stirrer (3) to rotate is provided on the top surface of the shell (17).

3. The flotation machine for biogas slurry according to claim 1, characterized in that: The dual-layer dissolved gas release device (4) with different flow rates includes upper and lower release structures, and the dissolved gas water flow rate of each layer can be adjusted independently.

4. The flotation machine for biogas slurry according to claim 3, characterized in that: The lower release structure includes a lower release box (402), and a plurality of lower release tubes (403) are provided on the side wall of the lower release box (402). The upper release structure includes an upper release box (404), and a plurality of upper release tubes (405) are provided on the outer wall of the upper release box (404). The number of lower release tubes (403) is greater than the number of upper release tubes (405). A conveying pipe (401) is provided at the center of the lower release box (402) and the upper release box (404), and the conveying pipe (401) is connected to the dissolved gas tank (5).

5. The flotation machine for biogas slurry according to claim 1, characterized in that: The dissolved gas tank (5) is equipped with a pressure gauge (14) for monitoring the pressure inside the tank, and the bottom of the dissolved gas tank (5) is equipped with an outlet (15) for discharging excess gas inside the dissolved gas tank (5).

6. The flotation machine for biogas slurry according to claim 1, characterized in that: The dissolved gas tank (5) is connected to the clear water tank (11) via a pipeline.

7. The flotation machine for biogas slurry according to claim 1, characterized in that: The micro-nano aeration device (10) includes a plurality of aeration pipes arranged in parallel.

8. The flotation machine for biogas slurry according to claim 1, characterized in that: The aeration time of the micro-nano aeration device (10) is set according to the single-circle running time of the slag scraper (6), and the aeration time of the micro-nano aeration device (10) is set to 1 / 3 to 1 / 2 of the single-circle running time of the slag scraper (6).

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