Multi-stage anaerobic fluidized bed reaction device

Abstract

The utility model belongs to the technical field of wastewater treatment, and particularly relates to a multistage anaerobic fluidized bed reaction device, which is formed by connecting a plurality of UASB (Upflow Anaerobic Sludge Blanket) reactors in series in an up-down superposition manner, and comprises a mixing chamber, a fluidized bed reaction chamber, a deep purification reaction chamber, an effluent standing chamber and an internal circulation system, wherein the internal circulation system comprises a first-stage three-phase separator, a second-stage three-phase separator, a gas-liquid separator, a biogas lifting pipe I, a biogas lifting pipe II and a muddy water descending pipe; the first-stage three-phase separator is positioned between the effluent standing chamber and the deep purification reaction chamber; the second-stage three-phase separator is positioned between the effluent standing chamber and the deep purification reaction chamber; the gas-liquid separator is positioned above the standing chamber and is communicated with the tops of the biogas lifting pipe I, the biogas lifting pipe II and the muddy water descending pipe; the bottom of the first biogas lifting pipe is communicated with the first-stage three-phase separator, the bottom of the second biogas lifting pipe is communicated with the second-stage three-phase separator, and the bottom of the muddy water descending pipe is communicated with the mixing chamber.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, specifically relating to a multi-stage anaerobic fluidized bed reactor. Background Technology

[0002] The UASB reactor is a highly efficient anaerobic bioreactor for treating organic wastewater. It is widely used in the treatment of high-concentration organic wastewater, such as in the food processing, papermaking, printing and dyeing, and chemical industries. The UASB reactor effectively reduces COD and BOD in wastewater, and the biogas produced can be recovered and reused as energy. It also features low operating costs, requires no stirring equipment, has low energy consumption, and produces minimal sludge.

[0003] Traditional single-stage anaerobic fluidized bed reactors suffer from problems in practical applications, including low reaction efficiency, poor resistance to shock loads, severe sludge loss, low mass transfer efficiency, and high operating costs. The uneven distribution of microbial populations within a single-stage reactor makes it difficult to achieve efficient multi-stage anaerobic reactions (hydrolysis, acidification, hydrogen and acetic acid production, methanogenesis), leading to incomplete organic matter degradation. Single-stage reactors are poorly adaptable to fluctuations in influent quality and quantity, making them susceptible to shock loads and resulting in unstable operation. Due to the high hydraulic shear force within the fluidized bed, some activated sludge is easily lost with the effluent, reducing the sludge concentration and biomass within the reactor. The uneven mixing of the gas, liquid, and solid phases within a single-stage reactor leads to low mass transfer efficiency, affecting the degradation rate of organic matter; furthermore, high energy consumption is required to maintain the fluidized state, and the pretreatment requirements for the influent are high, increasing operating costs.

[0004] Therefore, this application provides a multi-stage anaerobic fluidized bed reactor to solve the problems existing in the practical application of traditional single-stage anaerobic fluidized bed reactors.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this utility model and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Utility Model Content

[0006] The purpose of this invention is to provide a multi-stage anaerobic fluidized bed reactor to improve reaction efficiency and organic matter degradation rate; enhance resistance to shock loads and adapt to fluctuations in influent water quality and quantity; reduce sludge loss and maintain a high sludge concentration in the reactor; improve mass transfer efficiency and optimize gas-liquid-solid three-phase mixing; reduce operating costs and energy consumption and pretreatment requirements.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A multi-stage anaerobic fluidized bed reactor, comprising multiple UASB reactors stacked and connected in series, includes:

[0009] The mixing chamber is located at the bottom of the reaction apparatus;

[0010] A fluidized bed reaction chamber is located above the mixing chamber;

[0011] A deep purification reaction chamber is located above the fluidized bed reaction chamber;

[0012] The effluent settling chamber is located above the deep purification reaction chamber;

[0013] The internal circulation system includes a primary three-phase separator, a secondary three-phase separator, a gas-liquid separator, a biogas riser pipe I, a biogas riser pipe II, and a sludge downcomer. The primary three-phase separator is located between the effluent settling chamber and the deep purification reaction chamber. The secondary three-phase separator is located between the effluent settling chamber and the deep purification reaction chamber. The gas-liquid separator is located above the settling chamber. The top of the biogas riser pipe I is connected to the cyclone gas-liquid separator, and its bottom is connected to the primary three-phase separator. The top of the biogas riser pipe II is connected to the cyclone gas-liquid separator, and its bottom is connected to the secondary three-phase separator. The top of the sludge downcomer is connected to the cyclone gas-liquid separator, and its bottom is connected to the mixing chamber.

[0014] Preferably, the water outlet area of ​​the water outlet settling chamber is equipped with a clear liquid water collector.

[0015] Preferably, the bottom of the reaction device is equipped with a water distributor and a sludge discharge system; the sludge discharge system consists of a sludge discharge pipe, a sludge discharge pump, a sludge discharge valve, and a sludge collection device.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The multi-stage anaerobic fluidized bed reactor of this utility model significantly improves the reaction efficiency and operational stability by dividing the anaerobic reaction process into multiple stages, while reducing the operating cost and sludge loss rate.

[0018] (2) The multi-stage anaerobic fluidized bed reactor of this utility model can further improve the applicability and economy of the equipment by adopting modular design and automated control system. It is suitable for the treatment of various high-concentration organic wastewater and has broad application prospects. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the internal structure of the device of this utility model;

[0020] Explanation of key figure labels:

[0021] 1. Mixing chamber; 2. Fluidized bed reaction chamber; 3. Deep purification reaction chamber; 4. Effluent settling chamber; 5. Primary three-phase separator; 6. Secondary three-phase separator; 7. Gas-liquid separator; 8. Biogas riser pipe 1; 9. Biogas riser pipe 2; 10. Sludge downcomer; 11. Clear liquid effluent collector; 12. Water distributor; 13. Sludge removal system. Detailed Implementation

[0022] The technical solution of this utility model patent will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0023] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the utility model.

[0024] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0025] See attached document Figure 1 A multi-stage anaerobic fluidized bed reactor is constructed by stacking and connecting multiple UASB reactors vertically, reaching a height of 16-25m and a height-to-diameter ratio typically of 4-8. It consists of five basic parts: a mixing chamber 1, a fluidized bed reaction chamber 2, a deep purification reaction chamber 3, an internal circulation system, and an effluent settling chamber 4. The internal circulation system is the core structure of this embodiment, comprising a multi-stage three-phase separator, multiple biogas riser pipes, a gas-liquid separator 7, and a sludge-water downcomer 10.

[0026] In this embodiment, the internal circulation system includes a primary three-phase separator 5, a secondary three-phase separator 6, a gas-liquid separator 7, a biogas riser 1 8, a biogas riser 2 9, and a sludge downcomer 10. The primary three-phase separator 5 is located between the effluent settling chamber 4 and the deep purification reaction chamber 3. The secondary three-phase separator 6 is located between the effluent settling chamber 4 and the deep purification reaction chamber 3. The gas-liquid separator 7 is located above the settling chamber. The top of the biogas riser 1 8 is connected to the cyclone gas-liquid separator 7, and its bottom is connected to the primary three-phase separator 5. The top of the biogas riser 2 9 is connected to the cyclone gas-liquid separator 7, and its bottom is connected to the secondary three-phase separator 6. The top of the sludge downcomer 10 is connected to the cyclone gas-liquid separator 7, and its bottom is connected to the mixing chamber 1.

[0027] In actual use, the production wastewater, after pH and temperature adjustments, first enters the mixing chamber 1 at the bottom of the reactor. There, it is thoroughly mixed with the internal circulating sludge-water mixture from the sludge downcomer 10 before entering the fluidized bed reactor 2 for COD biochemical degradation. The COD volumetric loading here is very high, and most of the influent COD is degraded here, producing a large amount of biogas. The biogas is collected by a multi-stage three-phase separator.

[0028] The expansion work done on the liquid during biogas bubble formation creates a lift effect, causing the mixture of biogas, sludge, and water to rise along the biogas lift pipe 8 to the gas-liquid separator 7 at the top of the reactor. In the gas-liquid separator 7, the biogas is separated from the sludge and water and discharged into the treatment system. The sludge-water mixture then enters the mixing chamber 1 at the bottom of the reactor via the sludge downcomer 10, where it is thoroughly mixed with the influent before entering the fluidized bed reactor 2, forming a so-called internal circulation. The separation of biogas and liquid by the gas-liquid separator 7 reduces gas interference with the reactor; the separated biogas is collected and utilized, further minimizing the impact of gas on reactor operation. Returning some sludge to the mixing chamber 1 via the sludge downcomer 10 increases the biomass within the reactor, enhances the organic matter degradation capacity, maintains a high sludge concentration within the reactor, and helps reduce sludge loss.

[0029] Depending on the influent COD load and the different structures of the reaction devices, the internal circulation flow rate can reach 0.5-5 times the influent flow rate. After treatment in fluidized bed reaction chamber 2, a portion of the wastewater participates in the internal circulation; the remaining wastewater passes through the primary three-phase separator 5 and enters the granular sludge fluidized bed zone of the deep purification reaction chamber 3 for residual COD degradation and biogas production, thus improving and ensuring the effluent quality. Since most of the COD has been degraded, the COD load in the deep purification reaction chamber 3 is low, and the biogas production is also small. The biogas produced in the deep purification reaction chamber 3 is collected by the secondary three-phase separator 6, enters the gas-liquid separator 7 through the biogas riser pipe 9, and is then discharged from the treatment system.

[0030] After being treated in the deep purification reaction chamber 3, the wastewater passes through the two-stage three-phase separator 6. The supernatant is discharged through the effluent area of ​​the effluent settling chamber 4 and enters the clear effluent collector 11, while the granular sludge is returned to the sludge bed in the deep purification reaction chamber 3. The treated clear water is discharged from the reaction device through the effluent outlet, which is equipped with a flow stabilizing device to reduce water flow disturbance and improve the quality of the effluent.

[0031] On the other hand, the multi-stage anaerobic fluidized bed reactor of this embodiment is equipped with a water distributor 12 and a sludge removal system 13 at the bottom. The water distributor 12 evenly introduces wastewater into each stage of the reaction unit, ensuring uniform influent distribution and avoiding local overload. Each stage of the reaction unit optimizes the distribution of microbial populations for specific anaerobic reaction stages (such as hydrolysis, acidification, methanogenesis, etc.), thereby improving reaction efficiency. By controlling the hydraulic retention time (HRT) and sludge retention time (SRT) of each stage of the reaction unit, efficient organic matter degradation is achieved. The sludge removal system 13 typically consists of a sludge removal pipe, a sludge removal pump, a sludge removal valve, and a sludge collection device, etc., and is used for periodic sludge removal, maintaining the dynamic balance of the sludge bed within the reactor, ensuring the efficient and stable operation of the reactor, and restoring the overall anaerobic fluidized bed reaction purification function.

[0032] In the reactor, wastewater enters from the bottom, is evenly distributed by the distributor 12, and then flows upward. Sludge particles gradually settle during the ascent, eventually forming a sludge bed at the bottom of the reactor. As the reactor operates, the sludge bed gradually thickens, resulting in a higher sludge concentration at the bottom. When the sludge bed reaches a certain thickness or the sludge concentration becomes too high, the sludge discharge system 13 is activated, the sludge discharge valve is opened, and the bottom sludge is discharged from the reactor through the discharge pipe using gravity or a sludge pump. The sludge discharge valve must have good sealing and corrosion resistance to prevent sludge leakage or blockage. The discharge pipe is typically located at the bottom of the reactor and employs a multi-point discharge design to ensure uniform sludge discharge and avoid localized blockages. The discharge volume and frequency are dynamically adjusted based on the sludge bed thickness, sludge concentration, and reactor operating conditions (such as sludge bed thickness, sludge concentration, and influent load), typically ranging from 5% to 10% of the total sludge volume in the reactor.

[0033] Furthermore, the reactor in this embodiment employs an automated control system that monitors the influent water quality, quantity, and reactor operating status in real time, achieving intelligent operation, ensuring stable operation of the reactor, and improving treatment efficiency. Automatic sludge removal can also be achieved through the control system, initiating the sludge removal operation based on preset parameters or real-time monitoring data. Regular sludge removal removes aged sludge and inert substances, maintaining the efficient degradation capacity of the sludge bed; by controlling the sludge bed thickness, the risk of sludge loss with the effluent can be reduced. Regular sludge removal also reduces the corrosion and wear of equipment caused by sludge accumulation, which helps extend the service life of the reactor. In addition, the sludge removal system 13 prevents the water distributor 12 from clogging, ensuring uniform water flow distribution and improving the operating efficiency of the reactor.

[0034] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the present invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the present invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the present invention, as well as various different choices and variations. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. A multi-stage anaerobic fluidized bed reactor, comprising multiple UASB reactors stacked and connected in series, characterized in that, include: The mixing chamber is located at the bottom of the reaction apparatus; A fluidized bed reaction chamber is located above the mixing chamber; A deep purification reaction chamber is located above the fluidized bed reaction chamber; The effluent settling chamber is located above the deep purification reaction chamber; The internal circulation system includes a primary three-phase separator, a secondary three-phase separator, a gas-liquid separator, a biogas riser pipe I, a biogas riser pipe II, and a sludge downcomer. The primary three-phase separator is located between the effluent settling chamber and the deep purification reaction chamber. The secondary three-phase separator is located between the effluent settling chamber and the deep purification reaction chamber. The gas-liquid separator is located above the settling chamber. The top of the biogas riser pipe I is connected to a cyclone gas-liquid separator, and its bottom is connected to the primary three-phase separator. The top of the biogas riser pipe II is connected to the cyclone gas-liquid separator, and its bottom is connected to the secondary three-phase separator. The top of the sludge downcomer is connected to the cyclone gas-liquid separator, and its bottom is connected to the mixing chamber.

2. The multi-stage anaerobic fluidized bed reactor according to claim 1, characterized in that, The effluent area of ​​the effluent settling chamber is equipped with a clear effluent collector.

3. The multi-stage anaerobic fluidized bed reactor according to claim 1, characterized in that, The bottom of the reaction device is equipped with a water distributor and a sludge discharge system; the sludge discharge system consists of a sludge discharge pipe, a sludge discharge pump, a sludge discharge valve, and a sludge collection device.

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