Anaerobic reactor and method for rapidly degassing sludge

Abstract

The anaerobic reactor comprises a shell with an opening in the top, a water distribution device, a muddy water lifting device and a biogas guiding device are sequentially arranged in the shell from bottom to top at intervals, the water distribution device is connected with a water inlet pipe, and the muddy water lifting device is connected with a water outlet pipe. The muddy water lifting device comprises a gas collecting hood and an upflow pipe connected to the center of the top of the gas collecting hood, the biogas guiding device comprises a three-phase separator and an exhaust pipe connected to the center of the top of the three-phase separator, the exhaust pipe is connected with the biogas tank, the upflow pipe spirally extends upwards, and the total muddy water lifting amount of the muddy water lifting device is more than three times of the water inlet amount. When the anaerobic reactor operates under a high-load condition, rapid degassing of anaerobic sludge can be realized, sludge leakage of the anaerobic reactor is effectively prevented, and a support is provided for retention of sufficient sludge in the reactor and efficient and stable operation of the reactor.

Description

Technical Field

[0001] The invention relates to the technical field of anaerobic reactors, in particular to an anaerobic reactor for rapid sludge degassing and a method thereof. Background Art

[0002] Sufficient sludge volume is the key link for the rapid startup and efficient and stable operation of the anaerobic reactor.

[0003] At present, mainstream anaerobic reactors such as IC, EGSB, and UASB usually operate with bottom water inlet and top water outlet, and both water flow and air flow in the reactor are in an upward flow state.

[0004] In the anaerobic reactor, biogas exists in the form of bubbles, and there are different sizes. Usually, large-bubble biogas is formed by the merger of multiple small-bubble biogas. When anaerobic microorganisms decompose organic matter, the initial biogas produced is small-bubble biogas, which is usually tightly combined with sludge and difficult to separate. In contrast, large-bubble biogas is easier to release from the sludge. When biogas and sludge are combined together, the dual effects of the rising water flow and the floating of biogas in the anaerobic reactor can easily cause the anaerobic reactor to run out of mud. Especially when the anaerobic reactor is operated under high load conditions, the problem of mud running is more serious due to the high gas production intensity. If the mud running problem cannot be effectively solved, the anaerobic reactor cannot operate efficiently and stably due to insufficient mud.

[0005] Therefore, rapid degassing of anaerobic sludge is of great significance to effectively alleviate the sludge leakage of anaerobic reactors and ensure the efficient and stable operation of the reactor. Summary of the invention

[0006] The purpose of the present invention is to provide an anaerobic reactor for rapid sludge degassing and a method for using the same to solve the problems existing in the prior art. Rapid sludge degassing and the use of the descending water flow formed on the periphery of the mud and water lifting device can realize rapid reflux of the lifted sludge and the floating of the bottom mud layer under pressure, which can effectively inhibit the sludge from running and provide support for the efficient and stable operation of the anaerobic reactor.

[0007] The object of the present invention is achieved as follows: an anaerobic reactor for rapid degassing of sludge comprises a shell with an opening at the top, in which a water distribution device, a mud and water lifting device and a biogas diversion device are sequentially arranged from bottom to top, the water distribution device is connected to a water inlet pipe, the mud and water lifting device comprises an air collecting hood and an ascending flow pipe connected to the top center of the air collecting hood, the biogas diversion device comprises a three-phase separator and an exhaust pipe connected to the top center of the three-phase separator, the exhaust pipe is connected to a biogas tank, the ascending flow pipe extends upward in a spiral shape, and the total amount of mud and water lifted by the mud and water lifting device is more than 3 times the amount of water inlet.

[0008] The present invention changes the mud and water flow state and flow velocity of different parts of the anaerobic reactor through a specially designed mud and water lifting device in an anaerobic reactor in which both the water flow and the air flow are in an ascending flow state and the flow velocity of each part is the same. For example, on the basis of the original mud and water ascending flow state, a self-circulating flow state and a descending flow state (outside the mud and water lifting device) are formed; the ascending flow velocity of mud, air and water in the ascending flow pipe is faster than the flow velocity of other parts.

[0009] Specifically, in the anaerobic reactor for rapid sludge degassing of the present invention, a specially designed mud and water lifting device is installed between the water distribution device and the biogas diversion device of the anaerobic reactor. The biogas below the mud and water lifting device is drained into the mud and water lifting device. The density difference formed in the process of the biogas rising in the mud and water lifting device is used as the driving force to lift the mud and water below the mud and water lifting device to the bottom of the three-phase separator, so as to realize the self-circulation of the lifted mud and water with the mud and water lifting device as the center. First, the strong disturbance effect formed in the process of the rapid rise of the mud and water in the lifting device is utilized to realize the primary separation of the sludge and the gas; second, the reverse flow of the sludge and the gas formed on the periphery of the mud and water lifting device is utilized to realize the secondary separation of the sludge and the gas. By quickly removing the biogas combined with the sludge, the sludge can be effectively prevented from running under the condition of high gas production intensity.

[0010] Compared with the rod-shaped upflow pipe, under the same vertical height, the spiral upflow pipe can extend the flow distance of muddy water in the upflow pipe, speed up the upflow velocity of muddy water, and realize regular rotation during the upflow process, thus strengthening the disturbance of air and water flow in the upflow pipe on sludge and improving the degassing effect. Even under high load conditions, when a large amount of biogas is produced in the anaerobic reactor, the reactor can be operated efficiently and stably.

[0011] In summary, when the anaerobic reactor of the present invention operates under high load conditions, it can also achieve rapid degassing of anaerobic sludge, effectively prevent sludge leakage from the anaerobic reactor, retain sufficient sludge in the reactor, and provide support for efficient and stable operation of the reactor.

[0012] As a further improvement of the present invention, the inner diameter of the upflow pipe does not exceed 100 mm, the vertical height of the upflow pipe is more than 1 / 4 of the inner height of the shell, and the mud and water flow rate in the upflow pipe is controlled at more than 30 m / h, thereby ensuring that the total amount of mud and water lifted by the mud and water lifting device reaches more than 3 times the water intake, thereby ensuring the sludge degassing effect.

[0013] As a further improvement of the present invention, the height-to-diameter ratio of the shell is greater than 4. Compared with a reactor with a low height-to-diameter ratio, an anaerobic reactor with a high height-to-diameter ratio has better automatic sludge washing and pre-granulation efficiency, and can significantly improve the treatment effect.

[0014] As a further improvement of the present invention, there are several mud and water lifting devices, and the number of mud and water lifting devices can be increased or decreased according to the size of the effective area of ​​the anaerobic reactor. A first guide plate is provided between the gas collecting hoods of the mud and water lifting device, and a second guide plate is provided between the gas collecting hood and the inner wall of the shell, so as to guide the biogas generated below the gas collecting hood into the mud and water lifting device.

[0015] As a further improvement of the present invention, a third guide vane is provided between the three-phase separator and the inner wall of the shell to intercept the fine sludge and prevent the sludge from running away.

[0016] The present invention also provides a method for rapid degassing of sludge using the above anaerobic reactor, comprising the following steps: (1) Add seed sludge into the anaerobic reactor. The amount of seed sludge added is 1 / 3 of the effective volume of the anaerobic reactor, and ensure that the gas collection hood is submerged in the seed sludge; (2) The wastewater to be treated is passed into the anaerobic reactor in a continuous flow manner, and the anaerobic reactor is started under the condition that the initial water load is above 0.25 kgCOD / (kgVS.d); (3) When the COD removal rate of the anaerobic reactor reaches more than 80% stably, the influent load is increased by more than 20% until the design load is reached.

[0017] Based on the structure of the anaerobic reactor of the present invention, the method can start the anaerobic reactor under a relatively high initial water inlet load, and subsequently, as the wastewater treatment efficiency of the anaerobic reactor is improved, the water inlet load is continuously increased to improve the gas production intensity of the anaerobic reactor. As the gas production intensity of the anaerobic reactor increases, the total amount of mud and water lifted by the mud and water lifting device increases accordingly. When the gas production intensity of the anaerobic reactor reaches a certain value, the total amount of mud and water lifted by the mud and water lifting device is greater than the water inlet. Among the mud and water lifted by the mud and water lifting device, the part that is greater than the water inlet forms a downflow around the mud and water lifting device and flows back into the mud and water lifting device, forming a self-circulation with the mud and water lifting device as the center. When the influent load reaches the design load, the total amount of mud and water lifted by the mud and water lifting device reaches more than 3 times the influent volume. The strong disturbance effect formed by the regular rapid rotation and rising process of the mud and water in the spiral ascending flow pipe realizes the rapid separation of sludge and gas. At the same time, the mud and water that is larger than the influent volume forms a self-circulation from the inside (rising) to the outside (descending) in the local area of ​​the anaerobic reactor with the mud and water lifting device as the center, and utilizes the descending water flow formed on the periphery of the mud and water lifting device to realize the rapid return of the lifted sludge and the floating of the bottom mud layer, which can effectively inhibit the sludge from running, and provide support for the efficient and stable operation of the anaerobic reactor.

[0018] In summary, the present invention can effectively prevent sludge from leaking out under high gas production intensity conditions by quickly removing the biogas combined with the sludge. Even under high load conditions, when a large amount of biogas is produced in the anaerobic reactor, the reactor can still be operated efficiently and stably.

[0019] The present invention changes the mud and water flow state and flow velocity of different parts of the anaerobic reactor through a specially designed mud and water lifting device in an anaerobic reactor in which both the water flow and the air flow are in an ascending flow state and the flow velocity of each part is the same. For example, on the basis of the original mud and water ascending flow state, a self-circulating flow state and a descending flow state (outside the mud and water lifting device) are formed; the ascending flow velocity of mud, air and water in the ascending flow pipe is faster than the flow velocity of other parts.

[0020] As a further improvement of the present invention, during the start-up and operation phases of the anaerobic reactor, the gas collecting hood is always kept submerged in the seed sludge to ensure the reaction effect.

[0021] As a further improvement of the present invention, the amount of seed sludge added in step (1) is 1 / 3 of the effective volume of the anaerobic reactor to ensure the reaction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the anaerobic reactor for rapid degassing of sludge according to the present invention.

[0023] Among them, 1 is a water inlet pipe, 2 is a water distribution device, 3 is a first guide vane, 4 is a second guide vane, 5 is an air collecting hood, 6 is an upflow pipe, 7 is a third guide vane, 8 is a three-phase separator, 9 is a biogas tank, 10 is a water outlet weir, 11 is seed sludge, and 12 is an inclined angle of the air collecting hood. DETAILED DESCRIPTION

[0024] like Figure 1 The anaerobic reactor for rapid degassing of sludge shown includes a shell with an opening at the top. The height-to-diameter ratio of the shell is above 4. Compared with reactors with a low height-to-diameter ratio, anaerobic reactors with a high height-to-diameter ratio have better automatic sludge washing and pre-granulation efficiency, which can significantly improve the treatment effect. A water distribution device 2, a mud and water lifting device, and a biogas diversion device are sequentially arranged in the shell from bottom to top. There are several mud and water lifting devices, and the number of mud and water lifting devices can be increased or reduced according to the size of the effective area of ​​the anaerobic reactor. Seed sludge 11 is placed in the shell.

[0025] The water distribution device 2 is connected to the water inlet pipe 1 to pass the wastewater to be treated. The water distribution device 2 makes the water distribution more uniform, so that the sewage can evenly react with the seed sludge 11 at the bottom of the anaerobic reactor to reduce the organic matter content in the sewage. The top side of the anaerobic reactor is provided with a water outlet weir 10 to discharge the supernatant after separation.

[0026] The mud and water lifting device includes an air collecting hood 5 and an ascending flow pipe 6 connected to the top center of the air collecting hood 5. The air collecting hood is a shape that tapers from bottom to top, such as an inverted funnel, and its slope angle is less than 60°. A first guide plate 3 is provided between the air collecting hoods 5, and a second guide plate 4 is provided between the air collecting hood 5 and the inner wall of the shell, so as to guide the biogas generated below the air collecting hood 5 into the mud and water lifting device. The outlet of the ascending flow pipe 6 is arranged below the biogas guide device and is spaced at a certain distance to prevent fine sludge from rushing into the biogas guide device with the air flow. The ascending flow pipe 6 extends upward in a spiral shape. Compared with the rod-shaped ascending flow pipe, under the same vertical height, the spiral ascending flow pipe 6 can extend the flow distance of mud and water in the ascending flow pipe, accelerate the rising flow rate of mud and water, and realize regular rotation during the rising process of mud and water, thereby strengthening the disturbing effect of the air flow and water flow in the ascending flow pipe on the sludge.

[0027] The biogas guide device comprises a three-phase separator 8 and an exhaust pipe connected to the top center of the three-phase separator 8, and the exhaust pipe is connected to the biogas tank 9. A third guide plate 7 is arranged between the three-phase separator 8 and the inner wall of the shell to intercept fine sludge and prevent sludge from running.

[0028] When the gas production intensity remains unchanged, by reducing the inner diameter of the riser 6, the mud and water flow rate in the riser can be increased, and the total amount of mud and water lifted by the mud and water lifting device can be increased, and vice versa. Similarly, when the gas production intensity remains unchanged, by lengthening the vertical height or length of the riser 6, the mud and water flow rate in the riser can also be increased, and the total amount of mud and water lifted by the mud and water lifting device can be increased, and vice versa. In this embodiment, the inner diameter of the riser 6 does not exceed 100 mm, the vertical height of the riser 6 is more than 1 / 4 of the height of the shell, and the mud and water flow rate in the riser 6 is controlled at more than 30 m / h, thereby ensuring that the total amount of mud and water lifted by the mud and water lifting device is controlled at more than 3 times the water intake.

[0029] The method for rapid degassing of sludge in an anaerobic reactor of this embodiment comprises the following steps: (1) Add seed sludge into the anaerobic reactor. The amount of seed sludge added is about 1 / 3 of the effective volume of the anaerobic reactor, and ensure that the gas collection hood 5 is submerged in the seed sludge during the startup and operation stages of the anaerobic reactor; (2) The wastewater to be treated is introduced into the anaerobic reactor in a continuous flow manner, with an initial influent load of 0.25 kg COD / (kgVS.d) or more, and the anaerobic reactor is started; (3) When the COD removal rate of the anaerobic reactor reaches more than 80% stably, the influent load is increased by more than 20% until the design load is reached.

[0030] Based on the structure of the anaerobic reactor of the present embodiment, the present method can start the anaerobic reactor under a relatively high initial water inlet load, and subsequently, as the wastewater treatment efficiency of the anaerobic reactor is improved, the water inlet load is continuously increased to improve the gas production intensity of the anaerobic reactor. As the gas production intensity of the anaerobic reactor increases, the total amount of mud and water lifted by the mud and water lifting device increases accordingly. When the gas production intensity of the anaerobic reactor reaches a certain value, the total amount of mud and water lifted by the mud and water lifting device is greater than the water inlet. Among the mud and water lifted by the mud and water lifting device, the part that is greater than the water inlet forms a downflow around the mud and water lifting device and flows back into the mud and water lifting device, forming a self-circulation with the mud and water lifting device as the center. When the influent load reaches the design load, the total amount of mud and water lifted by the mud and water lifting device reaches more than 3 times of the influent volume. The strong disturbance effect formed by the regular rapid rotation and rising process of the mud and water in the spiral rising flow pipe 6 realizes the rapid separation of sludge and gas. At the same time, the mud and water that is larger than the influent volume forms a self-circulation from the inside (rising) to the outside (descending) in the local area of ​​the anaerobic reactor with the mud and water lifting device as the center, and utilizes the descending water flow formed on the periphery of the mud and water lifting device to realize the rapid return of the lifted sludge and the floating of the bottom mud layer, which can effectively inhibit the sludge from running, and provide support for the efficient and stable operation of the anaerobic reactor.

[0031] The sludge rapid degassing method of the anaerobic reactor of this embodiment, the sludge degassing path: First, the strong disturbance effect formed by the regular and rapid rotation and rising of muddy water in the spiral rising flow pipe 6 is utilized to achieve the primary separation of sludge and gas.

[0032] Secondly, the reverse flow of sludge descending and gas ascending formed on the periphery of the mud and water lifting device is utilized to realize the secondary separation of sludge and gas.

[0033] The present invention can effectively prevent sludge from leaking out under high gas production intensity conditions by quickly removing the biogas combined with the sludge. Even under high load conditions, when a large amount of biogas is produced in the anaerobic reactor, the efficient and stable operation of the anaerobic reactor can be achieved.

[0034] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. An anaerobic reactor for rapid degassing of sludge, comprising a shell with an opening at the top, wherein a water distribution device, a muddy water lifting device and a biogas diversion device are sequentially arranged from bottom to top in the shell, wherein the water distribution device is connected to a water inlet pipe, the muddy water lifting device comprises an air collecting hood and an ascending flow pipe connected to the top center of the air collecting hood, the biogas diversion device comprises a three-phase separator and an exhaust pipe connected to the top center of the three-phase separator, and the exhaust pipe is connected to a biogas tank, characterized in that: The rising flow pipe extends upward in a spiral shape, and the total amount of mud and water lifted by the mud and water lifting device is more than 3 times the amount of water intake.

2. The anaerobic reactor for rapid sludge degassing according to claim 1, characterized in that: The inner diameter of the ascending flow pipe does not exceed 100 mm, the vertical height of the ascending flow pipe is more than 1 / 4 of the inner height of the shell, and the muddy water flow rate in the ascending flow pipe is controlled to be more than 30 m / h.

3. The anaerobic reactor for rapid sludge degassing according to claim 1, characterized in that: The aspect ratio of the shell is greater than 4.

4. The anaerobic reactor for rapid sludge degassing according to claim 1, characterized in that: There are a plurality of mud and water lifting devices, a first guide plate is arranged between the air collecting hoods of the mud and water lifting devices, and a second guide plate is arranged between the air collecting hood and the inner wall of the shell.

5. The anaerobic reactor for rapid sludge degassing according to claim 1, characterized in that: A third guide plate is arranged between the three-phase separator and the inner wall of the shell.

6. A method for rapid degassing of sludge, using the anaerobic reactor according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Add seed sludge into the anaerobic reactor. The amount of seed sludge added should be more than 1 / 4 of the effective volume of the anaerobic reactor, and ensure that the gas collection hood is submerged in the seed sludge; (2) The wastewater to be treated is passed into the anaerobic reactor in a continuous flow manner, and the anaerobic reactor is started under the condition that the initial water load is above 0.25 kg COD / (kgVS.d); (3) When the COD removal rate of the anaerobic reactor reaches more than 80% stably, the influent load is increased by more than 20% until the design load is reached.

7. The method for rapid degassing of sludge according to claim 6, characterized in that: During the startup and operation phases of the anaerobic reactor, the gas collecting hood was kept submerged in the seed sludge.

8. The method for rapid degassing of sludge according to claim 6, characterized in that: In step (1), the amount of seed sludge added is 1 / 3 of the effective volume of the anaerobic reactor.

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