A device for treating biogas sludge based on hydrodynamic cavitation and biogasification mixer

Abstract

The application discloses a device for treating biogas sludge based on a hydraulic cavitation and biogasification mixer, which comprises a tank body, a rotating shaft arranged in the tank body, a guide wheel, a first axial flow impeller and a second axial flow impeller which are sequentially and interval arranged on the rotating shaft from top to bottom, a bearing tower arranged at the bottom of the tank body, a first vertical pipe arranged on the bearing tower, a Venturi tube and a second vertical pipe which are sequentially arranged on the first vertical pipe and sequentially communicated, and a driving mechanism for driving the rotating shaft to rotate, wherein the first axial flow impeller blades are located outside the second vertical pipe, and the first axial flow impeller blades are located inside the second vertical pipe; the device can efficiently degrade the refractory substances in the biogas sludge through the axial flow impeller and the Venturi tube to generate cavitation at the throat of the Venturi tube; and the device has the advantages that the axial flow impeller is a power source and can rotate forward or reversely, so that the liquid in the pipe can flow forward or reversely, and the biogas sludge in the tank can be fully circulated, mixed and treated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biogas sludge treatment, in particular to a device for treating biogas sludge based on a hydrodynamic cavitation and a biogas sludge mixing device. BACKGROUND

[0002] While the biogas project is developing rapidly, a large amount of anaerobic digestion residues, i.e. biogas sludge, is produced, and the resource utilization of the biogas sludge has become a bottleneck restricting the popularization and application of anaerobic digestion. Few biogas projects in China have enough land to accommodate the biogas sludge, and if the biogas sludge is not disposed of reasonably and sufficiently, the high content of organic matter, nitrogen, phosphorus and pathogenic microorganisms in the biogas sludge will enter the environment, causing secondary pollution and resource waste. The properties of the biogas sludge vary with the raw materials, and there may be toxic and harmful substances such as heavy metals and pathogenic bacteria. Livestock and poultry manure is used as the raw material for anaerobic digestion, and contains a certain concentration of antibiotics. When crop residues are used as the raw material for anaerobic fermentation, a small amount of herbicides and bactericides may be contained.

[0003] Cavitation is a fluid dynamics phenomenon in which the formation, growth, contraction and finally collapse of cavities occur when the local pressure of the flow is lower than the saturation vapor pressure at the corresponding temperature. When cavitation occurs, the molecular bonds of the flowing liquid will produce strong bursts, and at the same time, local extreme high temperature (1900-5000K) and high pressure (up to 140MPa-170Mpa) are formed at the burst point, accompanied by strong shock waves and micro-jets. According to Bernoulli's equation, the sum of the pressure head and the velocity head remains unchanged at the same level, and the velocity head can be increased and the pressure head can be decreased, so that the local pressure is reduced below the saturation vapor pressure of the liquid, thereby cavitation occurs. The fluid can flow through a Venturi tube to cause cavitation. The Venturi tube is a pipe that is first contracted and then gradually expanded. When the liquid flows in the Venturi tube, the dynamic pressure (velocity head) reaches a maximum value at the narrowest part of the pipe, and the static pressure (pressure head) reaches a minimum value. The velocity of the liquid rises because the through-flow cross-sectional area decreases. The entire flow experiences the pipe narrowing process in the same time, and the pressure decreases in the same time, thereby cavitation occurs. The hydrodynamic cavitation device with a Venturi tube can be applied to the field of biogas sludge treatment. The strong hydrodynamic shear force can break and rupture the carbon bonds in the main chain of macromolecules, achieving the purpose of degrading high molecular organic matter. In addition, the high temperature and high pressure generated during the collapse of the cavitation cloud can effectively degrade the refractory organic matter and pathogenic microorganisms in the biogas sludge, and play a role in disinfection and sterilization. SUMMARY

[0004] The purpose of the present application is to provide a device for treating biogas sludge based on a hydrodynamic cavitation and a biogas sludge mixing device, to improve the degradation efficiency of refractory substances in biogas sludge.

[0005] To achieve the above object, the present application provides the following scheme:

[0006] The device for treating biogas sludge based on the hydraulic cavitation and the biogasification mixer comprises a tank body, a rotating shaft arranged inside the tank body, a driving mechanism for driving the rotating shaft to rotate, a guide wheel, a first axial flow impeller and a second axial flow impeller which are sequentially and spacedly arranged on the rotating shaft from top to bottom, a bearing tower arranged at the bottom of the tank body, a first vertical pipe arranged on the bearing tower, a Venturi tube arranged on the first vertical pipe and communicated with the first vertical pipe, and a second vertical pipe arranged on the Venturi tube and communicated with the Venturi tube, wherein the first axial flow impeller is located outside the second vertical pipe, and the second axial flow impeller is located inside the second vertical pipe.

[0007] Preferably, the blades of the first axial flow impeller and the second axial flow impeller are spiral blades, the inner diameter of the spiral blade is d, the outer diameter of the spiral blade increases first and then decreases along the axial direction, the maximum outer diameter D is 2d, the thickness is δ=(0.065-0.07)d, and a circular arc structure is adopted at the outer edge of the spiral blade,

[0008] The helix angle of the spiral blade is β=13-15 degrees, the blade pitch is 0.96d, the blade width increases first and then decreases along the axial direction, the minimum leaf width is 0, the maximum leaf width is 0.5d, the inner and outer helix lines of the blade are three-dimensional curves, the inner helix line is 6.6d, the outer helix line is 9.5d, the blade wrap angle is 720 degrees, and the axial height of the blade is 1.93d.

[0009] Preferably, the Venturi tube comprises a circular pipe and diffusion pipes arranged at both ends of the circular pipe and communicated with the circular pipe, and the inner diameter of the diffusion pipe gradually increases away from the circular pipe.

[0010] Preferably, a detachable gas cover is arranged at the top of the tank body, the rotating shaft penetrates through the gas cover, and the driving mechanism is arranged on the gas cover and connected with the rotating shaft.

[0011] Preferably, the driving mechanism is a driving motor, the output shaft of the driving motor is connected with the rotating shaft through an elastic coupling, and the driving motor is used for driving the rotating shaft to rotate forward or reversely.

[0012] Preferably, the first vertical pipe and the second vertical pipe are connected with the inner wall of the tank body through fourfold pull lines, and the fourfold pull lines are perpendicular to the first vertical pipe and the second vertical pipe.

[0013] Preferably, a sealing ring is arranged between the gas cover and the tank body.

[0014] Preferably, the internal cross-sectional area of the tank body gradually increases from top to bottom, reaches the maximum in the middle, and then gradually decreases to the bottom.

[0015] Preferably, the upper end of the second vertical pipe is a diverging pipe.

[0016] Preferably, the surfaces of the first and second axial flow impellers and the guide wheel are provided with an anti-corrosion coating.

[0017] The present application has the following technical effects relative to the prior art:

[0018] 1. The present application can efficiently degrade the refractory substances in the biogas sludge through the axial flow impeller cooperating with the Venturi tube to generate cavitation at the throat of the Venturi tube; the advantage of the present application lies in that the axial flow impeller is a power source and can rotate forward or reversely, so that the liquid in the pipe can flow forward or reversely, and the biogas sludge in the tank can be fully circulated and mixed for treatment.

[0019] 2. The guide wheel on the rotating shaft of the device in the present application can effectively disperse the biogas sludge over a large area onto the surface of the suspended matter.

[0020] 3. The first and second axial flow impellers in the present application can rotate clockwise and counterclockwise, the entire pipeline flows in both directions, and the efficiency of treating the biogas sludge in the tank body is higher. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings described in the following only constitute some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0022] Figure 1 It is a structural schematic diagram of the gradually changing shape of the tank body of the present application;

[0023] Figure 2 It is a structural schematic diagram of the non-gradually changing shape of the tank body of the present application;

[0024] Figure 3 It is a structural schematic diagram of the spiral blade of the present application;

[0025] Among them, 1, driving motor; 2, rotating shaft; 3, elastic coupling; 4, guide wheel; 5, first axial flow impeller; 6, Venturi tube; 7, gas cover; 8, sealing ring; 9, tank body; 10, fourfold stay; 11, second vertical pipe; 12, first vertical pipe; 13, bearing tower; 14, second axial flow impeller. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0027] The present application aims to provide a device for treating biogas sludge based on hydrodynamic cavitation and biogasification mixer, so as to improve the degradation efficiency of refractory substances in biogas sludge.

[0028] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0029] Reference Figures 1 to 3 The device for treating biogas sludge based on hydrodynamic cavitation and biogasification mixer comprises a tank body, a rotating shaft arranged inside the tank body, a driving mechanism for driving the rotating shaft to rotate, guide wheels arranged on the rotating shaft in sequence from top to bottom, a first axial flow impeller and a second axial flow impeller, a bearing tower arranged at the bottom of the tank body, a first vertical pipe arranged on the bearing tower, a Venturi tube arranged on the first vertical pipe and communicating with the first vertical pipe, and a second vertical pipe arranged on the Venturi tube and communicating with the Venturi tube, the first axial flow impeller is located outside the second vertical pipe, and the second axial flow impeller is located inside the second vertical pipe. The present application can efficiently degrade refractory substances in biogas sludge through the axial flow impeller and the Venturi tube to generate cavitation at the throat of the Venturi tube. The advantage of the present application is that the axial impeller is a power source, which can rotate forward or reverse, so that the liquid in the pipe can flow forward or reverse, and the biogas sludge in the tank can be fully circulated and mixed for treatment.

[0030] Further, the blades of the first axial flow impeller and the second axial flow impeller are spiral blades, the inner diameter of the spiral blade is d, the outer diameter of the spiral blade increases first and then decreases along the axial direction, the maximum outer diameter D is 2d, the thickness is δ=(0.065-0.07)d, the outer edge of the spiral blade adopts a circular arc structure, which makes the shape of the spiral blade conform to the streamline shape, thereby reducing the hydraulic loss, the helix angle of the spiral blade is β=13 degrees to 15 degrees, the blade pitch is 0.96d, the blade width increases first and then decreases along the axial direction, the minimum blade width is 0, and the maximum blade width is 0.5d, the inner and outer helix lines of the blade are three-dimensional curves, the inner helix line is 6.6d, the outer helix line is 9.5d, the blade wrap angle is 720 degrees, and the blade height along the axial direction is 1.93d. Such spiral blades have obvious advantages when used for conveying materials with large viscosity and compressibility, and can complete the functions of stirring and mixing materials during the conveying operation.

[0031] Reference Figures 1 to 2 The Venturi tube comprises a circular tube and diffusion tubes arranged at both ends of the circular tube and communicated with the circular tube, and the inner diameter of the diffusion tube gradually increases in the direction away from the circular tube.

[0032] Reference Figure 1 The top of the tank body is provided with a detachable air cover, the rotating shaft passes through the air cover, and the driving mechanism is arranged on the air cover and connected with the rotating shaft.

[0033] Reference Figure 1 The driving mechanism is a driving motor, the output shaft of the driving motor is connected with the rotating shaft through an elastic coupling, and the driving motor is used for driving the rotating shaft to rotate forward or reversely.

[0034] Reference Figures 1 to 2 The first vertical pipe and the second vertical pipe are connected with the inner wall of the tank body through four-ply wire, and the four-ply wire is perpendicular to the first vertical pipe and the second vertical pipe; the vibration of the pipeline caused by the high-speed rotation of the engine is avoided.

[0035] Reference Figure 1 A sealing ring is arranged between the air cover and the tank body.

[0036] Reference Figure 1 The internal cross-sectional area of the tank body gradually increases from top to bottom, reaches the maximum in the middle part, and then gradually decreases to the bottom.

[0037] Reference Figure 2 The internal cross section of the tank body is non-gradually changed from top to bottom.

[0038] Reference Figure 1 The upper end of the second vertical pipe is a gradually expanding pipe.

[0039] Further, the surfaces of the first axial flow impeller, the second axial flow impeller and the guide wheel are all provided with an anticorrosive coating.

[0040] Reference Figure 1 The lower end of the first vertical pipe is connected with three strong supporting bearing towers, the lower end of the bearing tower is fixed on the tank bottom of the marsh tank, and the number of the bearing towers includes but is not limited to three.

[0041] The use process of the present application is as follows:

[0042] The first working condition is to transport the biogas sludge from bottom to top. The motor rotates clockwise to drive the impeller and the guide wheel to rotate, at this time the upward suction force is generated in the pipeline, the biogas sludge and the sediment from the lower part of the biogas tank are first sucked into the first vertical pipe, the biogas sludge is transported upward in the first vertical pipe to the converging section of the Venturi tube, at this time the cross-sectional area of the pipeline is reduced, the flow rate of the biogas sludge is increased, and the pressure is reduced. The speed reaches the maximum at the throat of the Venturi tube 6, and the pressure is reduced to the minimum, at this time the biogas sludge is cavitated at the throat, and at the same time the local extreme high temperature (1900-5000K) and high pressure (up to 140MPa-170Mpa) are formed, accompanied by strong shock wave and microjet. The high temperature and high pressure generated by the collapse of the cavitation cloud can effectively degrade the refractory organic matter and pathogenic microorganisms in the biogas sludge, and the strong hydraulic shear force can break and fracture the carbon bonds in the main chain of macromolecules to degrade the high molecular organic matter. The biogas sludge treated by cavitation continues to flow upward into the diffuser section of the Venturi tube, at this time the cross-sectional area of the pipeline is increased, the flow rate of the biogas sludge is reduced, and the pressure is increased. The biogas sludge continues to flow upward into the second vertical pipe, and flows through the axial flow impeller in the second vertical pipe. The axial flow impeller rotates to drive the biogas sludge to move upward and impact the guide wheel, and the biogas sludge is sprayed to the wall surface of the tank body in a large area through the rotating guide wheel. The sprayed biogas sludge will avoid the formation of suspended slurry and destroy the existing coating. The whole process is repeated, the sediment at the bottom is continuously transported to the top, and the suspended matter on the surface is continuously transported to the bottom due to the action of gravity. The biogas sludge in the tank is fully mixed and cavitated.

[0043] Another working condition is to transport the biogas sludge from top to bottom, the motor rotates counterclockwise to drive the impeller and the guide wheel to rotate, at this time the suction force in the pipeline is generated downward, the suspended matter on the surface is sucked into the pipeline, the axial flow impeller rotates to drive the biogas sludge to flow into the second vertical pipe downward, the biogas sludge is transmitted downward in the second vertical pipe to reach the converging section of the Venturi tube, at this time the cross-sectional area of the pipeline is reduced, the flow rate of the biogas sludge is increased, and the pressure is reduced. The speed reaches the maximum at the throat of the Venturi tube, and the pressure is reduced to the minimum, at this time the biogas sludge is cavitated at the throat, and at the same time the local extreme high temperature (1900-5000K) and high pressure (up to 140MPa-170Mpa) are formed, accompanied by strong shock wave and microjet. The high temperature and high pressure generated by the collapse of the cavitation cloud can effectively degrade the refractory organic matter and pathogenic microorganisms in the biogas sludge, and the strong hydraulic shear force can break and fracture the carbon bonds on the main chain of macromolecules to degrade the high molecular organic matter. The biogas sludge treated by cavitation continues to flow downward into the diffuser section of the Venturi tube, at this time the cross-sectional area of the pipeline is increased, the flow rate of the biogas sludge is reduced, and the pressure is increased. The biogas sludge continues to flow downward into the first vertical pipe and flows out from the first vertical pipe to the bottom of the tank. The whole process is repeated, and the suspended matter on the surface is continuously transported to the bottom. At this time, the pressure at the bottom of the tank is relatively large, and the precipitate at the bottom is continuously transported to the bottom. The biogas sludge in the tank is fully mixed and cavitated.

[0044] Changes made according to actual requirements are within the scope of the present application. It should be noted that for those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the application. Any reference signs in the claims should not be considered as limiting the claims involved.

Claims

1. A device for treating biogas sludge based on hydrodynamic cavitation in conjunction with a biogas mixer, characterized by, The tank body, the rotating shaft arranged inside the tank body, the driving mechanism for driving the rotating shaft to rotate, the guide wheel, the first axial flow impeller and the second axial flow impeller arranged on the rotating shaft in sequence from top to bottom, the load-bearing tower arranged at the bottom of the tank body, the first vertical pipe arranged on the load-bearing tower and communicated with the load-bearing tower, the Venturi tube arranged on the first vertical pipe and communicated with the first vertical pipe, and the second vertical pipe arranged on the Venturi tube and communicated with the Venturi tube, the first axial flow impeller is located outside the second vertical pipe, and the second axial flow impeller is located inside the second vertical pipe. The blades of the first axial flow impeller and the second axial flow impeller are spiral blades, the inner diameter of the spiral blade is d, the outer diameter of the spiral blade increases first and then decreases along the axial direction, the maximum outer diameter D is 2d, the thickness is δ=(0.065-0.07)d, and a circular arc structure is adopted at the outer edge of the spiral blade. The helix angle of the spiral blade is β=13-15 degrees, the blade pitch is 0.96d, the blade width increases first and then decreases along the axial direction, the minimum leaf width is 0, the maximum leaf width is 0.5d, the inner and outer helix lines of the blade are three-dimensional curves, the inner helix line is 6.6d, the outer helix line is 9.5d, the blade wrap angle is 720 degrees, and the axial height of the blade is 1.93d.

2. The device for treating biogas sludge by hydraulic cavitation and biogasification mixer according to claim 1, characterized in that, The Venturi tube comprises a circular pipe and diffusion pipes arranged at both ends of the circular pipe and communicated with the circular pipe, and the inner diameter of the diffusion pipe gradually increases away from the circular pipe.

3. The device for treating biogas sludge by hydraulic cavitation and biogasification mixer according to claim 1, characterized in that, A detachable gas cover is arranged at the top of the tank body, the rotating shaft penetrates through the gas cover, and the driving mechanism is arranged on the gas cover and connected with the rotating shaft.

4. The device for treating biogas sludge by a hydrodynamic cavitation and biogasification mixer according to claim 3, characterized in that, The driving mechanism is a driving motor, the output shaft of the driving motor is connected with the rotating shaft through an elastic coupling, and the driving motor is used for driving the rotating shaft to rotate forward or reverse.

5. The device for treating biogas sludge by hydraulic cavitation and biogasification mixer according to claim 1, characterized in that, The first vertical pipe and the second vertical pipe are connected with the inner wall of the tank body through four times of pull wires, and the four times of pull wires are perpendicular to the first vertical pipe and the second vertical pipe.

6. The device for treating biogas sludge by hydraulic cavitation and biogasification mixer according to claim 3, characterized in that, A sealing ring is arranged between the gas cover and the tank body.

7. The device for treating biogas sludge by hydraulic cavitation and biogasification mixer according to claim 1, characterized in that, The cross-sectional area of the inside of the tank body gradually increases from top to bottom, reaches the maximum at the middle, and then gradually decreases to the bottom.

8. The device for treating biogas sludge by hydraulic cavitation and biogasification mixer according to claim 1, characterized in that, The upper end of the second vertical pipe is a gradually expanding pipe.

9. The device for treating biogas sludge by hydraulic cavitation and biogasification mixer according to claim 1, characterized in that, The surfaces of the first axial flow impeller, the second axial flow impeller and the guide wheel are provided with an anticorrosion coating.

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