Bubble coalescence device based on gas interface and digestion reactor
By designing a gas interface-based bubble coalescence device in an anaerobic digestion reactor, collecting and growing small bubbles into large bubbles and releasing them in the reactor, the problem of uneven mixing in the anaerobic digestion reactor is solved, and the problem of uneven mixing in the anaerobic digestion reactor is improved The mass transfer efficiency reduces costs.
Patent Information
- Application Number
- CN202421043477.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-14
- Publication Date
- 2025-02-11
- Estimated Expiration
- 2034-05-14
AI Technical Summary
Due to the high solids and non-Newtonian fluid characteristics in the anaerobic digestion reactor, it is difficult to achieve good mixing effect, resulting in uneven mass transfer, low process efficiency, and high investment and operation costs.
Design a bubble coalescing device based on gas interfaces, which generates local turbulence by collecting and condensing small bubbles generated in the reactor, so that they grow into large bubbles and release them at the release points distributed on the horizontal cross-section of the reactor, thereby generating local turbulence. Improve the mass transfer process.
Through the use of bubble coalescing devices, the potential kinetic energy of small bubbles in the reactor can be effectively collected and utilized, local turbulence can be generated, mass transfer process can be improved, mixing efficiency in the reactor, and cost can be reduced.
Smart Images
Figure CN222455009U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of digestion treatment, in particular to a bubble coalescence device based on a gas interface and a digestion reactor. Background Art
[0002] Anaerobic biological treatment methods can convert organic matter into biogas and are widely used in the fields of wastewater, sludge and biomass treatment. Biological anaerobic processes are usually carried out in large digestion tanks and require good mixing to achieve efficient reactions. In actual production, it is difficult to achieve good mixing due to the high solid content in the reactor. The substrate and nutrients added to the reactor are difficult to be quickly transferred and distributed throughout the reactor volume. In addition, since the working conditions of anaerobic sludge and biomass digestion have non-Newtonian fluid characteristics, the mixing energy required is greater than that of other Newtonian fluids, and mixing is more difficult to achieve.
[0003] Mixing in traditional anaerobic digesters is usually achieved by external circulation combined with mechanical mixing or external gas injection. The stirring power of a typical anaerobic digestion reactor requires 3-6 watts per cubic meter of reactor volume, and continuous or intermittent mixing can be used. The external circulation flow of the anaerobic digestion reactor is achieved by extracting the mixture in the reactor and injecting it back into the reactor at different heights or positions in the reactor. The mechanical mixing method of the anaerobic reactor can be achieved by a variety of mechanical mixers. The commonly used method is to arrange a vertical shaft mixer (with or without a diversion channel) in the center of the reactor. In addition, some cases of reactors with low aspect ratios have also been found to use submerged horizontal shaft mixers. For the mixing method of injected gas, part of the generated biogas is collected and compressed and then reinjected into the reactor from the low point at the bottom of multiple reactors. A diversion tube is usually set in the reactor to promote the circulation flow inside the reactor.
[0004] All of the above mixing methods are designed to generate the largest possible internal circulation, thereby generating convective mass transfer so that the newly added substrate and nutrients in the reactor are quickly dispersed throughout the reactor volume. However, due to the large volume of the reactor itself, which can usually reach several thousand cubic meters, it leads to uneven feed distribution, low process efficiency, and long digestion residence time, which further leads to increased investment and operating costs. In addition, due to the high viscosity of the sludge or slurry, the turbulence generated by the agitator cannot act on the entire reactor volume, resulting in uneven distribution of the externally introduced stirring power in the reactor, resulting in high turbulence areas around the mixing point, and some areas are dead zones with little or no convective mass transfer.
[0005] In fact, the biogas produced by anaerobic digestion is usually distributed in the entire anaerobic digestion reactor volume in the form of tiny, growable bubbles. The expansion of bubble size and the buoyancy generated by the bubbles provide a potential source of energy for mixing. In theory, the kinetic energy released by the process of producing biogas in an anaerobic digestion reactor is equivalent to 10-30% of the energy corresponding to the design stirring power of a conventional digestion reactor. However, since the average size of the bubbles is very small, usually below 2 mm, the bubble size is smaller than the minimum turbulent diameter (Kolmogorov diameter, also called Kolmogorov microscale) required to induce turbulence, that is, smaller than the eddy size required to produce convective mass transfer, therefore, the kinetic energy released in the biogas production process cannot be converted into mixing energy. Utility Model Content
[0006] In response to the above technical problems, the utility model discloses a bubble coalescing device and a digestion reactor based on a gas interface. The bubble coalescing device is used to collect and condense small bubbles generated in the reactor, and make them grow into large bubbles, which are released at release points distributed on the horizontal cross-section of the reactor to generate local turbulence, thereby improving the mass transfer process.
[0007] To this end, the technical solution of the utility model is:
[0008] A bubble coalescing device based on a gas interface is located in a reactor, and comprises a bubble coalescing release component which opens downward, a gas release hole is provided on the upper surface of the bubble coalescing release component, a gas buffer chamber is provided at the lower part of the bubble coalescing release component, the gas buffer chamber is connected to the gas release hole, a bubble coalescing portion is provided on one side of the bubble coalescing release component, and the bubble coalescing portion is located on one side of the gas buffer chamber.
[0009] With this technical solution, static coalescence on the gas interface makes it very likely that the attached bubbles will collide with the bubble coalescence portion. Since the contact angle between the bubble and the bubble coalescence portion is significantly smaller than the contact angle between two bubbles, the release of the bubble here is more likely to occur than the merging of two bubbles.
[0010] The bubble coalescence release member is a container with a downward opening, which is used to collect and condense small bubbles generated in the reactor, and collect them in the gas buffer chamber to grow into large bubbles, forming a gas-liquid interface with floccules and particles. These floccules and particles collide with the gas layer of the gas buffer chamber when rising in the reactor, and the collected gas is released in the gas release hole as larger bubbles, which can induce turbulence in the reactor, and the kinetic energy of the gas release is converted into mixing energy, which better promotes convective mass transfer and helps the mixing of the medium.
[0011] As a further improvement of the utility model, the bottom entrance of the gas release hole is located above the top of the bubble coalescing portion and at the high point of the bubble coalescing release component. This technical solution is beneficial to the release of bubbles.
[0012] As a further improvement of the utility model, the top of the gas buffer chamber is inclined downward from the gas release hole side to the bubble coalescing part side. Further, the upper surface of the bubble coalescing release member is inclined downward from the gas release hole side to the bubble coalescing part side.
[0013] As a further improvement of the utility model, the gas release hole is provided with a nozzle. Furthermore, the diameter of the gas release hole is not less than 10 mm.
[0014] As a further improvement of the utility model, the upper surface of the bubble coalescence release member is an inclined surface, or an upwardly convex curved surface or a folded surface (roof shape). Wherein, when the upper surface of the bubble coalescence release member is an inclined surface, the inclination direction is downwardly inclined from the gas release hole side to the bubble coalescence part side.
[0015] As a further improvement of the utility model, the bubble coalescing portion is an opening located on one side of the gas buffer chamber. This technical solution is conducive to the aggregation of small bubbles and the reflux of scum such as floccules or particles. The small bubbles that are gathered form a gas layer, which is conducive to the continuous adsorption of small bubbles, and then they are coalesced in the gas buffer chamber and released from the gas release hole in the form of large bubbles.
[0016] As a further improvement of the utility model, an exhaust chamber is provided on one side of the gas buffer chamber, the gas buffer chamber is separated from the exhaust chamber by a partition plate, a weir is provided at the bottom of the partition plate, and the gas release hole is located above the exhaust chamber and communicates with the exhaust chamber. With this technical solution, the exhaust chamber is separated from the gas buffer chamber by a partition plate with a weir, and the other gas in the gas buffer chamber enters the exhaust chamber through the weir and is then released from the gas release hole.
[0017] As a further improvement of the utility model, a plurality of bubble agglomeration and release components are arranged in an alternating manner. With this technical solution, more places in the diversion channel can be covered, so that the bubbles of floccules or particles attached with bubbles in the diversion channel are gathered as much as possible and released in the form of large bubbles, which is beneficial to mixing and mass transfer.
[0018] As a further improvement of the utility model, the gas interface-based bubble coalescing device comprises at least two rows of staggered bubble coalescing release members arranged vertically, the ratio of the spacing between bubble coalescing release members in the same row to the width of the bubble coalescing release members is 0.75 to 0.90, and the ratio of the vertical distance between bubble coalescing release members in adjacent rows to the horizontal distance between adjacent bubble coalescing release members on the left and right is 0.5 to 1.0. This technical solution is conducive to capturing more small bubbles, and providing release space for large bubbles that are coalesced, which is conducive to mixed mass transfer.
[0019] As a further improvement of the utility model, the gas release holes of the plurality of bubble coalescence and release components are evenly distributed on a horizontal cross section in the guide channel.
[0020] The present invention also discloses a digestion reactor, which comprises a reactor body. A flow guide channel is arranged in the reactor body, and the bubble coalescing device based on the gas interface as described above is arranged in the upper part of the flow guide channel.
[0021] As a further improvement of the utility model, an annular gap is provided between the reactor body and the flow guide channel. With this technical solution, the collected gas is released in the form of large bubbles at the distributed gas release holes, and the medium returns to the bottom of the reactor through the annular gap, so that the mixed mass transfer effect in the reactor is better.
[0022] Compared with the prior art, the beneficial effects of the utility model are:
[0023] By adopting the technical solution of the utility model, small bubbles generated in the anaerobic reactor can be collected and condensed, and they can be grown into large bubbles and released. In this process, the increase in bubble size increases the velocity gradient between the bubbles and the liquid, and generates local turbulence, thereby improving the mass transfer process. Therefore, the potential kinetic energy contained in the fine bubbles dispersed in the reactor can be collected and released at the distribution points on the cross section of the reactor. Compared with other coalescence devices, the bubble coalescence release component has a simple structure and lower installation cost, which can better promote mixed mass transfer. When the reactor adopts an intermittent external reinjection gas mixing method at the same time, the reinjected gas can flush the bubble coalescence part, produce a self-cleaning effect, and prevent scum accumulation in the bubble coalescence part. In addition, the reinjected gas is again diverted to the bubble coalescence release component for dispersion, further improving the overall mixing effect in the reactor. The technical solution of the utility model can be applied to digesters with high gas production rates and external injection of mixed gas. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 It is a schematic structural diagram of a gas interface-based bubble coalescing device in a reactor according to Example 1 of the utility model.
[0025] Figure 2 It is a schematic structural diagram of a bubble coalescing device based on a gas interface in Example 1 of the utility model.
[0026] Figure 3 It is a schematic structural diagram of a gas interface-based bubble coalescing device according to Example 2 of the utility model.
[0027] Figure 4 It is a schematic structural diagram of the bubble coalescence release component of Example 2 of the utility model, wherein (a) is the front side and (b) is the back side.
[0028] Reference numerals include:
[0029] 1-reactor, 2-flow channel, 3-medium, 4-annular gap;
[0030] 11-bubble coalescence release member, 12-gas release hole, 13-gas buffer chamber, 14-bubble coalescence part, 15-small bubbles, 16-large bubbles, 17-floccules or particles, 18-nozzle;
[0031] 21 - the first row of bubble coalescing and releasing members, 22 - the second row of bubble coalescing and releasing members, 23 - the third row of bubble coalescing and releasing members, 24 - the fourth row of bubble coalescing and releasing members; 25 - the exhaust chamber, 26 - the partition plate, 27 - the weir. DETAILED DESCRIPTION
[0032] The preferred embodiments of the present invention will be described in further detail below in conjunction with the accompanying drawings.
[0033] Example 1
[0034] like Figure 1 and Figure 2 As shown, a bubble coalescing device based on a gas interface is horizontally arranged in a flow guide channel 2 of a reactor 1, and comprises a plurality of bubble coalescing release members 11 opening downward, wherein the bubble coalescing release members 11 are provided with a gas release hole 12, a gas buffer chamber 13 is provided at the lower part of the bubble coalescing release member 11, and the gas buffer chamber 13 is communicated with the gas release hole 12, a bubble coalescing portion 14 is provided at one side of the bubble coalescing release member 11, and the bubble coalescing portion 14 is located at one side of the gas buffer chamber 13. The upper surface of the bubble coalescing release member 11 is an upwardly convex arc surface.
[0035] The bottom entrance of the gas release hole 12 is located above the top of the bubble coalescing portion 14 and at the high point of the bubble coalescing release member 11. This facilitates the coalesced gas in the gas buffer chamber to be released in the form of large bubbles from the gas release hole 12. Furthermore, the aperture of the gas release hole 12 is not less than 10 mm.
[0036] Further, the bubble coalescing portion 14 is an opening located at one side of the gas buffer chamber 14 .
[0037] Furthermore, the gas release holes 12 of each bubble coalescence and release member 11 are evenly distributed on the cross section of the flow guide channel 2 .
[0038] Furthermore, the gas release hole 12 is provided with a nozzle 18 .
[0039] With this technical solution, the medium 3 generating small bubbles 15 rises in the flow channel 2 to the coalescing device, and the floccules or particles 17 attached with small bubbles 15 rise and hit the bubble coalescing release member 11, where the small bubbles 15 gather in the bubble coalescing portion 14. The small bubbles 15 condense into an air cushion (gas layer) here and gather in the gas buffer chamber 13. In the absence of small bubbles 15, the floccules or particles continue to rise. The gas collected in the gas buffer chamber 13 is released in the form of large bubbles 16 at the distributed gas release holes 12, and then the medium 3 returns to the bottom of the reactor 1 through the annular gap 4, achieving better mixing and mass transfer.
[0040] Example 2
[0041] like Figure 3 and Figure 4 As shown, on the basis of Example 1, in this embodiment, the gas interface-based bubble coalescing device includes at least two rows of bubble coalescing release members 11 arranged alternately up and down. In this embodiment, four rows of bubble coalescing release members 11 are included, namely, a first row of bubble coalescing release members 21, a second row of bubble coalescing release members 22, a third row of bubble coalescing release members 23, and a fourth row of bubble coalescing release members 24.
[0042] Each bubble coalescence release member 11 has an opening at the bottom and a gas buffer chamber 13 at the bottom. A gas release hole 12 is provided on the upper surface of the bubble coalescence release member 11. The gas buffer chamber 13 is connected to the gas release hole 12. A bubble coalescence portion 14 is provided on one side of the bubble coalescence release member 11 for gathering small bubbles 15. The bubble coalescence portion 14 is located on one side of the gas buffer chamber 13.
[0043] like Figure 3 As shown, the ratio of the spacing b of the bubble coalescing release members 11 in the same row to the width B of the bubble coalescing release members 11 is b / B=0.75-0.90, and the ratio of the vertical distance h1 of the bubble coalescing release members 11 in adjacent rows to the horizontal distance between the left and right adjacent bubble coalescing release members 11 (i.e., the spacing b of the bubble coalescing release members 11 in the same row) h1 / b is 0.5-1.0. The minimum number of rows is 2.
[0044] like Figure 4As shown, the upper surface of the bubble coalescence release member 11 is inclined downward from the gas release hole 12 side to the bubble coalescence part 14 side, and the bottom of the gas release hole 12 is higher than the top of the bubble coalescence part 14, that is, the top of the bubble coalescence release member 11 has a low point relative to the release side and a high point relative to the gas release side. The upper surface of the bubble coalescence release member 11 is an upwardly convex folded surface. An exhaust chamber 25 is provided on one side of the gas buffer chamber 13, and the gas buffer chamber 13 is separated from the exhaust chamber 25 by a partition plate 26. A weir 27 is provided at the bottom of the partition plate 26. The gas release hole 12 is located above the exhaust chamber 25 and is connected to the exhaust chamber 25.
[0045] Example 3
[0046] A digestion reactor 1, such as Figure 1 As shown, it comprises a reactor body 1, a flow guide channel 2 is arranged in the reactor body 1, and an annular gap 4 is arranged between the reactor body 1 and the flow guide channel 2. The upper part of the flow guide channel 2 is provided with a bubble coalescing device based on a gas interface as described in Example 1 or Example 2.
[0047] In the description of the present invention, it should be understood that terms such as "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are orientations or positional relationships based on the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0048] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0049] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0050] The specific implementation methods described above are preferred implementation methods of the present utility model, and are not intended to limit the specific implementation scope of the present utility model. The scope of the present utility model includes but is not limited to the specific implementation methods. All equivalent changes made in accordance with the shape and structure of the present utility model are within the protection scope of the present utility model.
Claims
1. A bubble coalescing device based on a gas interface, characterized in that: It includes a bubble coalescence release component which opens downward, a gas release hole is provided on the upper surface of the bubble coalescence release component, a gas buffer chamber is provided at the lower part of the bubble coalescence release component, the gas buffer chamber is connected with the gas release hole, a bubble coalescence part is provided on one side of the bubble coalescence release component, and the bubble coalescence part is located on one side of the gas buffer chamber.
2. The gas interface-based bubble coalescing device according to claim 1, characterized in that: The bottom entrance of the gas release hole is located above the top of the bubble coalescing portion and at the high point of the bubble coalescing release member.
3. The gas interface-based bubble coalescing device according to claim 2, characterized in that: The upper surface of the bubble coalescence and release component is an inclined surface, or an upwardly convex curved surface or a folded surface.
4. The gas interface-based bubble coalescing device according to claim 2, characterized in that: The bubble coalescing portion is an opening located at one side of the gas buffer chamber.
5. The gas interface-based bubble coalescing device according to claim 2, characterized in that: The gas release hole is provided with a nozzle.
6. The gas interface-based bubble coalescing device according to claim 2, characterized in that: An exhaust chamber is provided on one side of the gas buffer chamber, the gas buffer chamber is separated from the exhaust chamber by a partition plate, a weir is provided at the bottom of the partition plate, and the gas release hole is located above the exhaust chamber and communicated with the exhaust chamber.
7. The gas interface-based bubble coalescing device according to any one of claims 1 to 6, characterized in that: A plurality of bubble coalescence releasing components are arranged in an alternating manner up and down, and the gas release holes of the plurality of bubble coalescence releasing components are evenly distributed on a horizontal cross section in the guide channel.
8. The gas interface-based bubble coalescing device according to claim 7, characterized in that: It comprises at least two rows of staggered bubble coalescing release members arranged vertically, the ratio of the spacing between the bubble coalescing release members in the same row to the width of the bubble coalescing release members is 0.75-0.90, and the ratio of the vertical distance between the bubble coalescing release members in adjacent rows to the horizontal distance between the left and right adjacent bubble coalescing release members is 0.5-1.
0.
9. A digestion reactor, characterized in that: It comprises a reactor body, wherein a flow guide channel is arranged in the reactor body, and a bubble coalescing device based on a gas interface as claimed in any one of claims 1 to 8 is arranged in the upper part of the flow guide channel.
10. The digestion reactor according to claim 9, characterized in that: An annular gap is provided between the reactor body and the flow guiding channel.