Volume-variable CSTR anaerobic fermentation tank

Abstract

The present invention relates to a volume-variable CSTR anaerobic fermentation tank, comprising a fermentation tank body. The fermentation tank body consists of a top cover and a tank body, the bottom of the tank body being connected to a tank foundation, and the interior of the tank body being divided into a jacking zone at the bottom and a fermentation zone at the top by means of an intermediate sealing layer; the bottom of the intermediate sealing layer is provided with a plurality of jacking units that extend and retract under the control by a controller; and the jacking units can drive the intermediate sealing layer to descend and ascend, thereby changing the volume of the fermentation zone. By means of the descending and ascending of the jacking units, the volume of the fermentation zone in the fermentation tank body may vary along with the fluctuation of feed quantities, so that the hydraulic retention time of the inside of the tank tends to be stable, thereby ensuring fermentation effect. Submersible agitators and crust-breaking agitators for breaking crusts are applied, which avoid affect on the progress of fermentation reactions, such that the fermentation effect and biogas yield are improved while reducing energy consumption, thereby further ensuring fermentation effect.

Description

Variable volume CSTR anaerobic fermenter Technical Field

[0001] This invention relates to the field of anaerobic fermenters, and more particularly to CSTR anaerobic fermenters with variable volume. Background Technology

[0002] As a major energy consumer, China considers the development and utilization of new energy sources to be of great significance to the sustainable development of the national economy. Biogas is an ideal gaseous fuel. Anaerobic fermentation refers to the process by which waste materials are stabilized under anaerobic conditions through the metabolic activities of microorganisms, while methane and CO2 are produced. The total mixed anaerobic digester (CSTR) is the main form of anaerobic fermentation in current engineering practice and is the main means of treating agricultural waste. Anaerobic fermentation takes place in an anaerobic digester, so the quality of the digester directly affects the fermentation efficiency.

[0003] As shown in Figure 1, the existing CSTR anaerobic digester mainly consists of a digester body 1, a tank foundation located at the bottom of the digester body 1, a feed inlet 4, a discharge outlet 5, a sludge discharge outlet 6, a gas outlet 7 set on the digester body 1, and a submersible agitator 12 and a shell-breaking agitator 13 set inside the digester body 1. The volume of the digester body 1 is fixed and cannot be adjusted. During use, due to the uncertainty of the raw material feed amount, the residence time of the feed in the digester varies, resulting in unstable anaerobic fermentation effect and large fluctuations in biogas production. Some organic waste floats on the surface of the reaction liquid and is difficult to decompose for a long time, which causes the organic waste to gradually clump together and form a crust on the surface of the reaction liquid, seriously affecting the fermentation process. When the raw material feed amount is large and the solid content is high, the solid content of the anaerobic sludge is also high, making it difficult to discharge sludge from the digester. Therefore, it is difficult to guarantee the fermentation effect.

[0004] Therefore, how to design a CSTR anaerobic fermenter with variable volume that can adjust the volume of the tank as needed to ensure fermentation effect has become a technical problem that urgently needs to be solved by those skilled in the art.

[0005] Summary of the Invention

[0006] In view of the above-mentioned deficiencies of the prior art, the present invention provides a CSTR anaerobic fermenter with variable volume, which can adjust the volume of the tank as needed to ensure fermentation effect.

[0007] To achieve the above technical objectives, the present invention provides a CSTR anaerobic fermenter with variable volume, including a fermenter body, the fermenter body being composed of a top cover and a tank body, the bottom of the tank body being connected to a tank foundation, and the interior of the tank body being divided into a bottom lifting area and a top fermentation area by an intermediate sealing layer.

[0008] The bottom of the intermediate sealing layer is provided with several lifting units that are controlled by a controller to extend and retract. The lifting units can drive the intermediate sealing layer to rise and fall, thereby changing the volume of the fermentation zone.

[0009] The output end of the lifting unit is connected to the bottom of the intermediate sealing layer, and the fixed end is connected to the foundation of the lifting system.

[0010] The fermentation zone has a feed inlet on one side of the top and a discharge outlet and a sludge discharge outlet on one side of the bottom; the top cover has an air outlet, and the lifting zone has a sludge discharge outlet on one side.

[0011] The fermentation area is equipped with a submersible agitator and a shell-breaking agitator, with the shell-breaking agitator located at the top of the submersible agitator.

[0012] Preferably, an upper limit plate is provided in the fermentation area, and a lower limit plate is provided in the lifting area. The upper limit plate and the lower limit plate cooperate to control the lifting and lowering height of the intermediate sealing layer.

[0013] Preferably, the intermediate sealing layer consists of three layers: two lower steel plates and a middle rubber sealing ring.

[0014] The lifting unit is a hydraulic telescopic device, and each lifting unit has an independent hydraulic system and control system.

[0015] The control system is a proportional valve.

[0016] Preferably, a manhole is provided on one side of the lifting area.

[0017] The beneficial effects of this invention are:

[0018] Due to the above-mentioned structural design, the volume of the fermentation area inside the fermenter can be varied with the fluctuation of the feed rate by raising and lowering the lifting unit, so that the hydraulic residence time inside the tank tends to be stable and the fermentation effect is guaranteed. The use of submersible agitator and shell-breaking agitator to break the shell does not affect the fermentation reaction, and improves the fermentation effect and biogas production while saving energy, thereby further guaranteeing the fermentation effect. Attached Figure Description

[0019] Figure 1 is a schematic diagram of the structure of the prior art;

[0020] Figure 2 is a schematic diagram of the structure of the present invention when the lifting unit is in a high position;

[0021] Figure 3 is a schematic diagram of the present invention when the lifting unit is in a low position;

[0022] Figure 4 is a schematic diagram of the lifting unit in this invention.

[0023] In the diagram: 1. Fermentation tank body, 2. Tank foundation, 3. Lifting system foundation, 4. Feed inlet, 5. Discharge outlet, 6. Sludge discharge outlet, 7. Air outlet, 8. Sewage outlet, 9. Upper limit plate, 10. Lifting unit, 11. Intermediate sealing layer, 12. Submersible agitator, 13. Shell breaking agitator, 14. Lower limit plate. Detailed Implementation

[0024] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention.

[0025] Example:

[0026] As shown in Figures 2-4, the variable volume CSTR anaerobic fermenter includes a fermenter body 1, which consists of a top cover and a tank body. The bottom of the tank body is connected to the tank foundation 2. The interior of the tank body is divided into a bottom lifting area and a top fermentation area by an intermediate sealing layer 11.

[0027] The bottom of the intermediate sealing layer 11 is provided with several lifting units 10 that are controlled by a controller to extend and retract. The lifting units 10 can drive the intermediate sealing layer 11 to rise and fall, thereby changing the volume of the fermentation zone.

[0028] The output end of the lifting unit 11 is connected to the bottom of the intermediate sealing layer 11, and the fixed end is connected to the lifting system foundation 3.

[0029] The fermentation area has a feed inlet 4 on one side of the top and a discharge outlet 5 and a sludge discharge outlet 6 on one side of the bottom, allowing materials to enter and exit the fermentation tank body 1; the top cover has a gas outlet 7 for collecting biogas, and a sludge discharge outlet 8 is provided on one side of the lifting area for cleaning debris in the lifting area without affecting the operation of the lifting unit 10.

[0030] The fermentation area is equipped with a submersible agitator 12 and a shell-breaking agitator 13. The shell-breaking agitator 13 is located on top of the submersible agitator 12. The submersible agitator 12 is used to agitate the material, and the shell-breaking agitator 13 is used at the top of the tank to eliminate the effect of material crusting, thereby improving the fermentation effect and biogas production while saving energy.

[0031] The main innovation of this invention lies in:

[0032] The effective volume of the fermentation zone inside the fermenter body 1 is controlled by raising and lowering the intermediate sealing layer 11 through the lifting unit 10, thereby achieving a constant hydraulic residence time and ensuring the fermentation effect.

[0033] Specifically, when the solid content of the anaerobic sludge in the fermenter body 1 is high, making it difficult to discharge the sludge from the fermenter, the lifting unit 10 can continuously raise the water level in the tank, thereby increasing the water head pressure in the tank and allowing the anaerobic sludge to be quickly squeezed out of the tank, thus realizing the self-draining function of the fermenter body 1.

[0034] An upper limit plate 9 is installed in the fermentation area, and a lower limit plate 14 is installed in the lifting area. The upper limit plate 9 and the lower limit plate 14 work together to control the lifting and lowering height of the intermediate sealing layer 11, ensuring a safe net height in the lifting area and facilitating subsequent equipment maintenance.

[0035] The intermediate sealing layer 11 consists of three layers: two lower steel plates and a middle rubber sealing ring. It separates the lifting area from the fermentation area, ensuring the water tightness of the fermentation tank body 1. At the same time, it can rise and fall together with the lifting unit 10 when it is started.

[0036] The lifting unit 10 is a hydraulic telescopic device. Each lifting unit 10 has an independent hydraulic system and control system. The control system is a proportional valve. Each lifting unit 10 can operate independently or can be controlled by the proportional valve of each lifting unit 10 to achieve synchronous lifting.

[0037] In some embodiments, a manhole is provided on one side of the lifting area, which can serve as a maintenance passage.

[0038] In other embodiments, the top cover is a hard top or membrane top structure.

[0039] Working principle and usage process of this invention:

[0040] The operator first obtains the daily feed rate through the flow meter at the front end of the process. By calculating the change in the daily feed rate, the operator obtains the change in the tank volume and begins to control the lifting unit 10. Each lifting unit 10 is equipped with an independent hydraulic system and electrical control system. Each lifting unit 10 can be operated independently or in conjunction (with switching and interlocking). The lifting and moving speed can be steplessly adjusted.

[0041] The lifting unit 10 features synchronous lifting control with alarm and adjustment recovery functions to ensure operational safety. The displacement value of the lifting unit 10 is transmitted to the PLC. After calculation by the PLC, the lifting displacement value is controlled by the proportional valve of each lifting unit 10 to achieve synchronous lifting. When the synchronization error exceeds the set range, an alarm is triggered and the unit stops. The operator then switches the control mode to single-action mode to fine-tune the level before lifting the workpiece synchronously.

[0042] The submersible agitators 12 inside the fermentation tank body 1 can be arranged in multiple layers inside the tank. The installation method is a space capsule type, which facilitates the maintenance and replacement of agitators. When the lifting begins, the lower submersible agitators 12 are turned off and exited into the tank through the space capsule without affecting the lifting progress. At the same time, the upper submersible agitators 12 are turned on to continue stirring. When the top shell breaking position is reached, the shell breaking agitator 13 is activated to break up the shelled part. When shell breaking is no longer needed, the lifting system lowers the liquid level to return to the normal operating liquid level, thereby improving the fermentation effect while saving energy.

[0043] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A CSTR anaerobic fermenter with variable volume, comprising a fermenter body, characterized in that: The fermentation tank body consists of a top cover and a tank body. The bottom of the tank body is connected to the tank foundation. The interior of the tank body is divided into a bottom lifting area and a top fermentation area by an intermediate sealing layer. The bottom of the intermediate sealing layer is provided with several lifting units, which can drive the intermediate sealing layer to rise and fall, thereby changing the volume of the fermentation zone; The output end of the lifting unit is connected to the bottom of the intermediate sealing layer, and the fixed end is connected to the foundation of the lifting system. The fermentation zone has a feed inlet on one side of the top and a discharge outlet and a sludge discharge outlet on one side of the bottom; the top cover has an air outlet, and the lifting zone has a sludge discharge outlet on one side. The fermentation area is equipped with a submersible agitator and a shell-breaking agitator, with the shell-breaking agitator located at the top of the submersible agitator.

2. The variable-volume CSTR anaerobic fermenter according to claim 1, characterized in that: An upper limit plate is provided in the fermentation area, and a lower limit plate is provided in the lifting area. The upper limit plate and the lower limit plate cooperate to control the lifting and lowering height of the intermediate sealing layer.

3. The variable-volume CSTR anaerobic fermenter according to claim 1 or 2, characterized in that: The intermediate sealing layer consists of three layers: two lower steel plates and a middle rubber sealing ring.

4. The variable-volume CSTR anaerobic fermenter according to claim 3, characterized in that: The lifting unit is a hydraulic telescopic device, and each lifting unit has an independent hydraulic system and control system.

5. The variable-volume CSTR anaerobic fermenter according to claim 4, characterized in that: The control system is a proportional valve.

6. The variable-volume CSTR anaerobic fermenter according to claim 5, characterized in that: A manhole is provided on one side of the lifting area.

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