EGSB reactor with middle-section gas stripping stirring

Abstract

The utility model provides an EGSB (Expanded Granular Sludge Bed) reactor with middle-section gas stripping stirring, which is characterized in that a reactor body is divided into a main reaction area at the lower part and a gas stripping stirring area at the upper part through a gas stripping gas inlet pipe, a biogas circulating conveying pipe is additionally arranged to connect a biogas collecting area at the top part with the gas stripping gas inlet pipe, and the self-produced biogas in the reactor body is recycled; the granular sludge and the water body in the gas stripping stirring area are fully stirred, so that the treatment effect is ensured, the biogas is assisted to be released from the sludge, the sludge sedimentation is accelerated, and the sludge loss is avoided. Meanwhile, water in the middle and the top of the reactor body is introduced into the main reaction area again through the arranged middle circulating pipe and the arranged water outlet circulating pipe respectively, the flow speed of the main reaction area is increased through the water circulation design, then the treatment efficiency is greatly improved, the EGSB reactor has the high-load treatment capacity, meanwhile, only one-stage three-phase separator is arranged, and the energy consumption is reduced. The volume load is effectively reduced, a larger expansion space is provided for a mud bed, and the stability and the processing performance of the system are enhanced.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, specifically relating to an EGSB reactor with mid-stage air-lift stirring. Background Technology

[0002] The EGSB anaerobic reactor is an improvement upon the existing UASB reactor, primarily in terms of increased height-to-diameter ratio, increased upflow velocity, enhanced sludge-water mixing, and improved mass transfer. With the increased upflow velocity, the sludge bed expands more significantly, resulting in more thorough contact between sludge particles. The EGSB reactor not only optimizes space utilization but also solves the short-circuiting and dead-zone problems commonly found in UASB reactors. This design allows the EGSB reactor to increase treatment capacity while occupying less space. Furthermore, the EGSB reactor incorporates an effluent recirculation system. In cases involving toxic substances or unstable water quality, the effluent can be recirculated to dilute the influent, reducing the impact on the system and enhancing its resistance to load fluctuations.

[0003] While increasing the upflow velocity in existing EGSB anaerobic reactors has improved treatment efficiency, it has also led to the following problems:

[0004] First, as the upflow velocity increases, sludge loss becomes more severe. The expansion of the sludge bed makes it easier for sludge to be lost with the effluent, which limits further increases in sludge concentration and upflow velocity within the reactor, thus restricting the load processing capacity of the EGSB reactor.

[0005] At the same time, this also places higher demands on the sludge-water separation performance of the three-phase separator. The separation capacity of the three-phase separator always has an upper limit. Under high-load operating conditions, the biogas production is large. If the biogas is not discharged in time, it will lead to a decrease in the density of granular sludge, a decrease in settling performance, and thus exacerbate the sludge runoff phenomenon.

[0006] In addition, the traditional two-stage three-phase separator design in reactors limits the expansion height of the mud bed, making it difficult to achieve higher volumetric loading.

[0007] Therefore, the key to improving the treatment capacity of EGSB reactors is to effectively retain granular sludge and prevent sludge loss while maintaining high load and high upward flow velocity. Utility Model Content

[0008] To address the problems of existing reactors, such as sludge leakage, low processing capacity, and small load volume, this invention provides a mid-section air-lift stirring EGSB reactor. The reactor body is cleverly divided into two functional zones by an air-lift inlet pipe: a lower main reaction zone and an upper air-lift stirring zone. A biogas circulation pipe connects the air-lift inlet pipe to the top biogas collection zone, recycling the naturally generated biogas within the reactor body to thoroughly stir the granular sludge and water in the air-lift stirring zone, promoting the release of biogas from the granular sludge and accelerating sludge settling. Furthermore, the configuration of the mid-section circulation pipe and the effluent circulation pipe allows water from the middle and top of the reactor body to flow back to the main reaction zone, respectively. This water circulation design enhances the upward flow velocity in the main reaction zone, thereby significantly improving the overall system processing efficiency.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] An EGSB reactor with mid-stage air-lift stirring includes: a reactor body, with a biogas collection zone at the top; an air-lift inlet pipe disposed within the reactor body, dividing the internal space of the reactor body into a lower main reaction zone and an upper air-lift stirring zone; and a biogas circulation pipe, with its two ends connected to the air-lift inlet pipe and the biogas collection zone, respectively, for circulating biogas generated within the reactor body into the reactor body to process granular sludge and water within the air-lift stirring zone. The reactor includes: a stirring device; several bubble dispersing devices, with several gas outlets on the biogas circulation conveying pipe, the openings of which face the gas lifting stirring zone; each bubble dispersing device being connected to the others to disperse the biogas into small bubbles; a central circulation pipe, with its two ends connected to the gas lifting stirring zone and the main reaction zone, respectively, to guide the purified water in the gas lifting stirring zone back to the main reaction zone for treatment; and a water outlet circulation pipe, with its two ends connected to the top water outlet of the reactor body and the main reaction zone, respectively.

[0011] In some embodiments, the EGSB reactor further includes a biogas pressure stabilizing cabinet, disposed on the biogas circulation and delivery pipe, for storing and stabilizing biogas pressure.

[0012] In some embodiments, the EGSB reactor further includes a biogas booster blower, disposed on the biogas circulation conveying pipe, for providing conveying power for the biogas circulating into the gas lift inlet pipe.

[0013] In some embodiments, the EGSB reactor further includes a gas lift inlet check valve, which is disposed on the biogas circulation delivery pipe and located at the inlet of the gas lift inlet.

[0014] In some embodiments, the biogas circulation delivery pipe has a U-shaped section near the inlet of the gas lift inlet pipe, with the bottom of the U-shaped section facing the top of the reactor body and the bottom of the U-shaped section being higher than the top of the reactor body.

[0015] In some embodiments, the EGSB reactor further includes a three-phase separator disposed between the gas stripping mixing zone and the biogas collection zone.

[0016] In some embodiments, the EGSB reactor further includes: an effluent weir disposed between the three-phase separator and the biogas collection zone; and an effluent pipe connected to the effluent weir to output purified water.

[0017] In some embodiments, the EGSB reactor further includes: a main inlet pipe connected to the inlet of the reactor body; an inlet feed pump installed on the main inlet pipe for providing power for conveying the inlet water; and several inlet branch pipes installed within the reactor body and connected to the main inlet pipe.

[0018] In some embodiments, the central circulation pipe and the outlet circulation pipe merge and are connected to the main inlet pipe; and / or, the outlet circulation pipe is equipped with an outlet circulation pump; and / or, the central circulation pipe is equipped with a central circulation flow regulating valve; and / or, the outlet circulation pipe is equipped with a main circulation flow regulating valve.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The EGSB reactor provided by this utility model features a gas inlet pipe inside the reactor body, dividing the internal space into a lower main reaction zone and an upper air-lift mixing zone. Furthermore, a central circulation pipe is added to return water from the middle section of the reactor body to the main reaction zone. This central circulation design allows for independent adjustment of the upward flow velocity in the main reaction zone and the air-lift mixing zone, increasing the water volume and flow rate in the main reaction zone and ensuring the reactor's treatment efficiency. In the upper air-lift mixing zone, biogas is used to thoroughly mix the granular sludge and wastewater, not only enhancing the treatment effect but also accelerating the release of biogas from the anaerobic granular sludge, improving the settling performance of the anaerobic granular sludge, effectively preventing sludge runoff, and ensuring the reactor's high-efficiency treatment performance.

[0021] 2. The EGSB reactor of this invention is equipped with a biogas circulation and delivery pipe, utilizing the biogas naturally generated from the granular sludge inside the reactor for stripping and stirring, eliminating the need for an external gas source. This design not only maintains the anaerobic reaction environment inside the reactor but also significantly improves treatment efficiency.

[0022] 3. This utility model uses biogas for stripping and stirring, which effectively prevents short-circuiting and dead zones that may occur inside the reactor body, ensuring the uniformity of the reactor environment and the consistency of the treatment effect.

[0023] 4. This invention incorporates a single-stage three-phase separator within the reactor body. Compared to the traditional two-stage three-phase separator configuration, this design allows for a higher expansion height of the sludge bed, expanding the reaction zone and increasing sludge concentration. This improvement not only increases the reactor's volumetric loading but also reduces material costs, achieving a more economical and efficient processing capacity. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Figure 1 This is a schematic diagram of the EGSB reactor provided by this utility model.

[0026] The meanings of the symbols in the attached diagram are as follows:

[0027] 1—Reactor body; 101—Main reaction zone; 102—Air lift stirring zone; 103—Air lift inlet pipe; 104—Bubble dispersing device; 105—Three-phase separator; 106—Effluent weir; 107—Biogas collection zone;

[0028] 2—Central circulation pipe; 201—Central circulation flow regulating valve;

[0029] 3—Outlet water circulation pipe; 301—Outlet water circulation pump; 302—Total circulation flow regulating valve;

[0030] 4—Biogas circulation conveying pipe; 401—Biogas pressure stabilizing cabinet; 402—Biogas booster blower; 403—Air lift inlet check valve; 404—U-shaped section;

[0031] 5—Main water inlet pipe; 501—Water inlet feed pump; 6—Branch water inlet pipe; 7—Water outlet pipe. Detailed Implementation

[0032] like Figure 1 As shown, this utility model provides an EGSB reactor with mid-stage air-lift stirring, comprising:

[0033] The reactor body 1 has a biogas collection area 107 and a water outlet at the top and a water inlet at the bottom.

[0034] The air-lift inlet pipe 103 is installed inside the reactor body 1, dividing the internal space of the reactor body 1 into the lower main reaction zone 101 and the upper air-lift stirring zone 102.

[0035] The biogas circulation conveying pipe 4 is connected at both ends to the gas lift inlet pipe 103 and the biogas collection area 107, respectively, so as to circulate the biogas generated in the reactor body 1 into the reactor body 1 to stir the granular sludge and water in the gas lift stirring area 102.

[0036] The EGSB reactor also includes a central circulation pipe 2 and an effluent circulation pipe 3. The two ends of the central circulation pipe 2 are connected to the air-lift stirring zone 102 and the main reaction zone 101, respectively, to return the purified water in the air-lift stirring zone 102 to the main reaction zone 101 for treatment. The two ends of the effluent circulation pipe 3 are connected to the top outlet of the reactor body 1 and the main reaction zone 101, respectively, to reintroduce a portion of the effluent into the main reaction zone 101 to maintain a good flow state within the reactor.

[0037] Preferably, after the middle circulation pipe 2 and the outlet circulation pipe 3 merge, they are connected to the inlet of the reactor body 1. This reintroduces the water located in the middle and end of the reactor body 1 into the main reaction zone 101, increasing the water volume in the main reaction zone 101, enhancing the upward flow velocity, and thus improving the hydraulic shear force. This effectively prevents sludge deposition in the main reaction zone 101, maintains the sludge in suspension, promotes the stable formation of sludge particles, and significantly enhances the pollutant treatment capacity, ensuring that most pollutants are efficiently treated in the main reaction zone 101.

[0038] In some embodiments, the EGSB reactor also includes a main inlet pipe 5, which is connected to the inlet at the bottom of the reactor body 1 to introduce water to be treated into the reactor body 1. The main inlet pipe 5 is also equipped with an inlet feed pump 501 to provide power for conveying the water.

[0039] The aforementioned central circulation pipe 2 and effluent circulation pipe 3 converge and connect to the main inlet pipe 5, coordinating the inlet water intake to reintroduce the water from the middle and end of the reactor body 1 into the main reaction zone 101. When treating water with high pollutant concentrations, this effluent circulation mechanism can effectively dilute the pollutant concentration in the inlet water, thereby mitigating the adverse effects on the granular sludge within the reactor body 1 and ensuring sludge stability and treatment efficiency.

[0040] Preferably, the outlet circulation pipe 3 is equipped with an outlet circulation pump 301 and a total circulation flow regulating valve 302 to precisely control the water flow; similarly, the middle circulation pipe 2 is also equipped with a middle circulation flow regulating valve 201 to optimize the distribution of circulation flow.

[0041] Furthermore, the reactor body 1 is equipped with several water inlet branch pipes 6, each of which is connected to the main water inlet pipe 5. Each water inlet branch pipe 6 is designed with several small holes, so that the water flowing in from the main water inlet pipe 5 can be evenly distributed to each branch pipe and flow out through these small holes, which improves the dispersion of water in the reactor body 1 and helps to improve the mixing efficiency inside the reactor.

[0042] Because the central circulation pipe 2 effectively introduces a portion of the water flow into the main reaction zone 101, the water flow rising to the gas mixing zone is relatively reduced. Under this configuration, the air lift inlet pipe 103 and the biogas circulation delivery pipe 4 work together to introduce biogas generated inside the reactor body 1 into the gas mixing zone. Under the action of this biogas, the granular sludge and water are thoroughly mixed, increasing the frequency of contact between the sludge and wastewater, thereby accelerating the degradation rate of pollutants. Simultaneously, the biogas generated by the granular sludge in the anaerobic environment can be smoothly integrated into the biogas input through the air lift inlet pipe 103 via gas diffusion. This process not only promotes the effective separation of anaerobic granular sludge and biogas but also ensures better sedimentation of the granular sludge, preventing "sludge run-off" and thus guaranteeing stable reactor operation and efficient sludge settling performance.

[0043] In addition, the introduction of biogas optimizes the fluid dynamics environment within the reactor, effectively reducing short-circuiting and dead zones, thereby improving overall treatment efficiency.

[0044] In some embodiments, the EGSB reactor further includes several bubble dispersion devices 104 disposed within the reactor body 1. Specifically, the biogas circulation conveying pipe 4 is provided with several gas outlets, the openings of which face the gas lift mixing zone 102. Correspondingly, each gas outlet is connected to a bubble dispersion device 104. Through these bubble dispersion devices 104, the biogas input from the gas lift inlet pipe 103 is effectively dispersed into fine and dense biogas bubbles. Under the action of the bubble dispersion devices 104, a negative pressure zone is formed, drawing in water from the main reaction zone 101. This water, along with the biogas bubbles, is ejected from the upper outlet of the bubble dispersion device 104, allowing the biogas generated in the anaerobic granular sludge to more quickly integrate into these biogas bubbles, thereby improving the settling properties of the granular sludge.

[0045] Furthermore, a biogas pressure stabilizing cabinet 401 is also provided on the biogas circulation and delivery pipe 4 to store the biogas discharged from the biogas collection area 107 and stabilize the pressure of this part of the biogas.

[0046] Furthermore, a biogas booster blower 402 is also installed on the biogas circulation conveying pipe 4 to provide power for the biogas circulating into the gas lift inlet pipe 103. That is, in this embodiment, the biogas circulation conveying pipe 4, the gas lift inlet pipe 103, the bubble dispersion device, the biogas pressure stabilizing cabinet 401, and the biogas booster blower 402 together constitute a highly efficient gas lift mixing system. Biogas in the biogas collection area 107 flows into the biogas circulation conveying pipe 4 and is temporarily stored in the biogas pressure stabilizing cabinet 401. Subsequently, the biogas booster blower 402 extracts biogas from the biogas pressure stabilizing cabinet 401 and pumps it into the bubble dispersion device through the gas lift inlet pipe 103. The biogas is dispersed into fine bubbles, which thoroughly mix the granular sludge and water in the gas lift mixing zone 102. This process also helps to promote the effective separation of biogas produced by the granular sludge under anaerobic conditions from the sludge itself, thereby accelerating the sedimentation of the sludge.

[0047] Preferably, a gas lift inlet check valve 403 is also installed on the biogas circulation conveying pipe 4. The gas lift inlet check valve 403 is located at the inlet position of the gas lift inlet pipe 103, that is, the gas lift inlet check valve 403 is installed on the biogas circulation conveying pipe 4 upstream of the connection with the inlet of the gas lift inlet pipe 103. After the gas lift is stopped, the wastewater in the reactor body 1 is prevented from being forced into the biogas circulation conveying pipe 4.

[0048] More preferably, the biogas circulation conveying pipe 4 has a U-shaped section 404 near the inlet of the gas lift inlet pipe 103. The bottom of the U-shaped section 404 faces the top of the reactor body 1, and the bottom of the U-shaped section 404 is higher than the top of the reactor body 1. The design of the U-shaped section 404 helps to maintain stable gas pressure in the gas lift inlet pipe 103. When biogas enters the gas lift mixing zone 102 through the gas lift inlet pipe 103, the U-shaped section 404 can reduce gas pressure fluctuations, ensuring that biogas enters the bubble dispersion device with a stable flow rate and pressure. The design of the U-shaped section 404 also prevents the risk of water flowing back into the biogas booster blower 402 and the biogas pressure stabilizing cabinet 401 when the biogas booster blower 402 is shut down.

[0049] In some embodiments, the EGSB reactor is further equipped with a three-phase separator 105, which is located between the air-lift mixing zone 102 and the biogas collection zone 107. The three-phase separator 105 can effectively separate the anaerobic granular sludge from the wastewater in the mixture generated in the air-lift mixing zone 102, preventing sludge from being lost with the water flow, maintaining the sludge concentration in the reactor, and separating biogas from the wastewater to ensure that the collected biogas is relatively pure and easy to reintroduce into the air-lift mixing zone 102. Compared with traditional EGSB reactors, this invention only installs one three-phase separator 105 inside the reactor body 1. This design allows the sludge bed to achieve a higher expansion height, expands the volume of the reaction zone, facilitates the increase of sludge concentration, and significantly improves the volumetric load of the reactor body 1, while also reducing material costs and achieving more economical and efficient treatment performance.

[0050] Furthermore, the EGSB reactor also includes an effluent weir 106 and an effluent pipe 7. The effluent weir 106 is located between the three-phase separator 105 and the biogas collection area 107, while the effluent pipe 7 is connected to the effluent weir 106. The water after the biogas and sludge are separated by the three-phase separator 105 can pass smoothly through the effluent weir 106 and be transported out of the reactor body 1 by the effluent pipe 7 to complete the final purification process.

[0051] In summary, the operation procedure of this EGSB reactor is as follows:

[0052] The wastewater to be treated is introduced into the reactor body 1 through the main inlet pipe 5, and then evenly distributed to the main reaction zone 101 through the branch inlet pipe 6, where it is thoroughly mixed with the granular sludge. As the water flows upward, the mixture reaches the gas mixing zone. Here, biogas supplied by the air lift inlet pipe 103 is refined into microbubbles through a bubble dispersion device, which agitates the granular sludge and wastewater. At the same time, the biogas produced by the anaerobic granular sludge merges with the biogas bubbles and rises together with the water to the three-phase separator 105. During this stage, the granular sludge settles, and the biogas in the water is separated by the three-phase separator 105 and rises to the biogas collection zone 107, then flows into the biogas circulation conveying pipe 4 for subsequent recycling. The purified water flows into the effluent weir 106 and is discharged from the reactor through the effluent pipe 7.

[0053] A portion of the purified water is combined with the water in the middle of the air-lift stirring zone 102, which is transported by the central circulation pipe 2, through the outlet circulation pipe 3. Together, they are mixed with the fresh inlet water from the main inlet pipe 5 and re-enter the main reaction zone 101. This circulation not only increases the upward flow velocity but also dilutes the inlet water, thereby enhancing the reactor's shock resistance and ensuring stable operation and efficient treatment.

[0054] The preferred embodiment of this utility model is provided as an inspiration. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model.

[0055] The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An EGSB reactor with mid-stage air-stripping stirring, characterized in that, include: The reactor body, with a biogas collection area at its top: An air-lift inlet pipe is installed inside the reactor body, dividing the internal space of the reactor body into a lower main reaction zone and an upper air-lift stirring zone. A biogas circulation conveying pipe, the two ends of which are connected to the gas lift inlet pipe and the biogas collection area respectively, is used to circulate the biogas generated in the reactor body into the reactor body to stir the granular sludge and water in the gas lift stirring zone. A plurality of bubble dispersion devices are provided, and a plurality of gas outlets are provided on the biogas circulation conveying pipe. The openings of the gas outlets face the gas lifting and stirring zone. The bubble dispersion devices are connected one to one to disperse the biogas into small bubbles. A central circulation pipe, with its two ends connected to the air-lift stirring zone and the main reaction zone respectively, to draw purified water from the air-lift stirring zone back to the main reaction zone for treatment; The water outlet circulation pipe has its two ends connected to the top outlet of the reactor body and the main reaction zone, respectively.

2. The EGSB reactor according to claim 1, characterized in that, Also includes: A biogas pressure stabilizing unit is installed on the biogas circulation and delivery pipe to store and stabilize biogas pressure.

3. The EGSB reactor according to claim 1, characterized in that, Also includes: A biogas booster fan is installed on the biogas circulation conveying pipe to provide power for the biogas circulating into the gas lift inlet pipe.

4. The EGSB reactor according to claim 1, characterized in that, Also includes: A check valve for the gas lift inlet pipe is installed on the biogas circulation conveying pipe and located at the inlet position of the gas lift inlet pipe.

5. The EGSB reactor according to claim 1, characterized in that, The biogas circulation conveying pipe has a U-shaped section near the inlet of the gas lift inlet pipe, with the bottom of the U-shaped section facing the top of the reactor body and the bottom of the U-shaped section being higher than the top of the reactor body.

6. The EGSB reactor according to any one of claims 1-5, characterized in that, Also includes: A three-phase separator is disposed between the gas stripping and mixing zone and the biogas collection zone.

7. The EGSB reactor according to claim 6, characterized in that, Also includes: A water outlet weir is provided between the three-phase separator and the biogas collection area. The outlet pipe is connected to the outlet weir to output purified water.

8. The EGSB reactor according to claim 1, characterized in that, Also includes: A main inlet pipe, which is connected to the inlet of the reactor body; An inlet water supply pump is installed on the main inlet pipe to provide power for conveying inlet water; Several water inlet branch pipes are installed inside the reactor body and connected to the main water inlet pipe.

9. The EGSB reactor according to claim 8, characterized in that, The central circulation pipe and the outlet circulation pipe merge and are connected to the main inlet pipe; and / or, The outlet circulation pipe is equipped with an outlet circulation pump; and / or, The central circulation pipe is equipped with a central circulation flow regulating valve; and / or, The outlet circulation pipe is equipped with a total circulation flow regulating valve.

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