A multi-swirl microbubble generator

Abstract

The present invention discloses a multi-swirl microbubble generator, comprising a hollow main pipeline, a connecting piece, a gas pipeline and a swirl structure, wherein the main pipeline comprises a liquid phase inlet arranged at the bottom and a gas-liquid outlet arranged at the top; the connecting piece is arranged in the middle section of the main pipeline, dividing the main pipeline into two sections, the upper section and the lower section; the cavity in the upper section of the main pipeline is a gas-liquid mixing cavity, and the cavity in the lower section of the main pipeline is a liquid inlet cavity; the connecting piece is provided with at least one connecting channel, which connects the gas-liquid mixing cavity and the liquid inlet cavity; the swirl structure is arranged in the lower part of the connecting channel and is installed on the inner wall of the connecting channel; the swirl structure comprises a swirl column and a swirl plate. The microbubble generator of the present invention forms a high-speed liquid swirl through the swirl structure, promotes the orifice shedding and bubble crushing process when the bubble is formed, and adopts a multi-channel parallel connecting structure to eliminate the swirl tail flow, thereby avoiding the bubble aggregation in the bubble conveying process.

Description

Technical Field

[0001] The present invention relates to the technical field of microbubbles and process intensification, and more specifically, to a multi-swirl microbubble generator. Background Art

[0002] Compared with macrobubbles (greater than 1000 microns), microbubbles (1-1000 microns) have the advantages of small size, large specific surface area, stable interface, long residence time, fast dissolution rate, good surface adsorption, etc. They can increase the contact area between gas and liquid phases and effectively improve the gas-liquid mass transfer rate. They have been widely used in petrochemical, wastewater treatment, aquaculture, mineral flotation, molten salt nuclear reactors and other fields. The equipment that produces microbubbles is generally referred to as a microbubble generator.

[0003] At present, the methods for generating microbubbles are mainly divided into dissolved gas release method, microporous aeration method, electrochemical method, fluid mechanics method, etc. The principle of dissolved gas release method is to reduce the local pressure so that the solubility of gas in the liquid phase is significantly reduced, and the gas phase is supersaturated and bubbles are precipitated. The microporous aeration method uses microporous media to cut compressed gas to form micro-nano bubbles. The electrochemical method refers to the electrolysis of liquid to form bubbles of non-vapor components. The fluid mechanics method includes the air entrainment and dispersion method and the mechanical stirring method, both of which are based on the principle of fluid mechanics to construct a two-phase flow field, and use the turbulent kinetic energy flow field of the liquid phase to shear and break the continuous airflow or macro bubbles to form a large number of bubbles. Among them, the fluid mechanics method has a simple structure and is easy to implement, and has been widely used.

[0004] Microbubble generating equipment using the principles of fluid mechanics include jet bubbling reactors and Venturi microbubble generators. In a jet bubbling reactor, gas enters from the bottom of the reactor through a gas distributor, and liquid enters from the top of the reactor through a liquid nozzle, generating a liquid jet to shear and break bubbles. There are two structures of Venturi microbubble generators. One is the traditional Venturi structure, which is mainly composed of a convergent section, a throat, and a divergent section. It uses the higher flow velocity of the liquid phase in the throat and the turbulent kinetic energy in the divergent section to shear and break bubbles. The other is a jet Venturi, which is mainly composed of a nozzle, a receiving chamber, a mixing section, and a diffusion section. The jet flow is sucked into the receiving chamber by the internal and external pressure difference. The two fluids enter the mixing section together, mix, and then enter the diffusion section to form a bubble flow.

[0005] In actual application, the Venturi microbubble generator relies on a smaller throat to produce a high-speed liquid jet, resulting in large fluid flow resistance loss, a larger average diameter of the generated bubbles, and a wider distribution of bubble sizes. The swirl-type Venturi microbubble generator is an optimized structure of the Venturi microbubble generator. By introducing a swirl field at the inlet of the Venturi pipeline, it promotes the detachment of bubbles at the orifice and the bubble crushing process, forming bubbles with smaller particle sizes. However, the bubbles in the swirl field gather toward the center, coalesce, and form a gas column, resulting in a reduction in the contact area between the gas and liquid phases. The cavity area occupied by the gas column wastes the mass transfer and reaction volume of the equipment.

[0006] In summary, the existing microbubble generators have the disadvantages of high energy consumption, discrete bubble size, and complex structure. The traditional single-channel Venturi microbubble generator produces poor bubble quality. It is necessary to optimize the structure of the microbubble generating device to improve the bubble generation effect, while making it compact, simple to operate, low in energy consumption and maintenance costs, and more industrially practical. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a multi-swirl microbubble generator. The microbubble generator forms a high-speed liquid swirl through a swirl structure, promotes the orifice shedding and bubble breaking process when bubbles are formed, and adopts a multi-channel parallel connection structure to eliminate the swirl tail flow, thereby avoiding the bubble aggregation caused by the swirl field during the bubble transportation process.

[0008] In order to solve the above technical problems, the invention adopts the following technical solutions:

[0009] A multi-swirl microbubble generator comprises a hollow main pipeline, a connecting piece, a gas pipeline and a swirl structure.

[0010] The main pipeline includes a liquid phase inlet arranged at the bottom and a gas-liquid outlet arranged at the top;

[0011] The connecting piece is arranged in the middle section of the main pipeline, dividing the main pipeline into two sections, the upper section and the lower section; the cavity in the upper section of the main pipeline is a gas-liquid mixing cavity, and the cavity in the lower section of the main pipeline is a liquid inlet cavity;

[0012] The connecting piece is provided with at least one connecting hole, which connects the gas-liquid mixing chamber and the liquid inlet chamber;

[0013] The swirl structure is arranged at the lower part of the communicating channel and is installed on the inner wall of the communicating channel; the swirl structure includes a swirl column and a swirl plate;

[0014] The outlet of the gas pipeline leads to the connecting hole on the connecting piece, and the outlet of the gas pipeline is arranged above the swirl structure.

[0015] Preferably, the gas-liquid mixing chamber has the same inner diameter as the main pipeline and is coaxially connected.

[0016] Preferably, the connecting channels are symmetrically and evenly distributed around the axis of the main pipeline, the number is 2-10, and the diameter is 1 / 5-3 / 4 of the main pipeline; more preferably, the inner diameter and length of each connecting channel are equal, and the number is 2 or 4.

[0017] Preferably, a gas flow control valve or a gas distributor is provided at the inlet of the gas pipeline, and a one-way valve is installed at the same time.

[0018] Preferably, the liquid phase inlet and the gas-liquid outlet are connected to external equipment by threaded connection or flange connection.

[0019] Preferably, the swirl column is a solid cylinder, which is coaxially installed at the entrance of the connecting channel. The diameter of the bottom surface of the cylinder is 1 / 3 to 2 / 3 of the inner diameter of the connecting channel, and the length is 1 / 2 to 3 / 4 of the connecting channel.

[0020] Preferably, the swirl plates include straight plates and curved plates with different curvatures. The number of swirl plates in each swirl structure is 3 to 10, which are symmetrically and evenly distributed around the axis of the swirl column. More preferably, the swirl plates are straight plates with a circular arc triangle cross-section, with an angle of 20° to 70° with the horizontal plane, and the number of swirl plates in each swirl structure is 3.

[0021] Preferably, all swirl plates in the swirl structure are of equal shape and size, and the diameter and length of the swirl columns are kept consistent; the swirl plate angles of the swirl structure in the same connecting channel are of the same direction and size, and the swirl plate angles of the swirl structures in adjacent connecting channels are of the same size and opposite directions; thereby ensuring that the swirl intensity of the swirl field in each connecting channel is equivalent, and the rotation directions of the swirl fields in adjacent connecting channels are opposite.

[0022] Any range described in the present invention includes the end value and any numerical value between the end values ​​and any sub-range formed by the end value or any numerical value between the end values.

[0023] Unless otherwise specified, all raw materials in the present invention can be purchased from the market, and the equipment used in the present invention can adopt conventional equipment in the relevant field or refer to the existing technology in the relevant field.

[0024] Compared with the prior art, the present invention has the following beneficial effects: :

[0025] The multi-swirl microbubble generator of the present invention is similar to the Venturi microbubble generator in principle. It forms a high-speed liquid swirl through a swirl structure, improves the turbulent kinetic energy of the liquid phase when the gas-liquid two-phase contacts, promotes the orifice shedding and bubble crushing process when the bubble is formed, and forms bubbles with a narrow size distribution and a small average diameter. The multi-channel parallel connection structure makes the gas flow evenly distributed in each connecting channel on the one hand, and on the other hand, the fluid converges in the gas-liquid mixing chamber after passing through the connecting channel, eliminating the swirl tail flow, reducing the probability of collision and coalescence between bubbles, and the bubble conveying effect is better. The multi-swirl microbubble generator of the present invention has the advantages of compact structure, high bubble generation quality, low operating energy consumption and maintenance cost, and good gas-liquid mass transfer effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0027] Figure 1 It is a three-dimensional structural schematic diagram of an embodiment of a microbubble generator of the present invention;

[0028] Figure 2 It is a three-dimensional structural schematic diagram of another embodiment of the microbubble generator of the present invention;

[0029] Figure 3 It is a structural schematic diagram of the swirl structure;

[0030] Figure 4 This is a schematic diagram of the structure of a conventional Venturi microbubble generator;

[0031] Figure 5 yes Figure 1 and Figure 4 The Sauter mean diameter of the bubbles produced by the microbubble generator shown; DETAILED DESCRIPTION

[0032] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0033] Various cross-sectional views of the embodiments disclosed in the present invention are shown in the accompanying drawings. These drawings are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the drawings and the relative sizes and positional relationships between them are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0034] At present, the existing microbubble generators have disadvantages such as high energy consumption, discrete bubble size, and complex structure. The traditional single-channel Venturi bubble generator produces bubbles of poor quality.

[0035] Based on this, Figure 1 or Figure 2 As shown, as one aspect of the present invention, the present invention provides a multi-swirl microbubble generator, comprising a hollow main pipeline 1, a connecting piece 2, a gas pipeline 3 and a swirl structure 4,

[0036] The main pipeline 1 includes a liquid phase inlet 11 arranged at the bottom and a gas-liquid outlet 12 arranged at the top;

[0037] The connecting piece 2 is in the middle section of the main pipeline 1, dividing the main pipeline 1 into two sections, the upper section and the lower section. The cavity in the upper section of the main pipeline 1 is a gas-liquid mixing cavity 13, and the cavity in the lower section of the main pipeline is a liquid inlet cavity 14.

[0038] The connecting member 2 is provided with at least one connecting hole 21, and the connecting hole 21 connects the gas-liquid mixing chamber 13 and the liquid inlet chamber 14;

[0039] The swirl structure 4 is disposed in the lower part of the communication channel 21 and is installed on the inner wall of the communication channel 21; the swirl structure 4 includes a swirl column 41 and a swirl plate 42;

[0040] The outlet of the gas pipeline 3 leads to the connecting channel 21 on the connecting piece 2 , and the outlet of the gas pipeline 3 is arranged above the swirl structure 4 .

[0041] According to some embodiments of the present invention, the gas-liquid mixing chamber 13 has the same inner diameter as the main pipeline 1 and is coaxially connected to simplify the structure and reduce flow resistance.

[0042] According to some embodiments of the present invention, Figure 1 or Figure 2 As shown, the connecting channels 21 are symmetrically and evenly distributed around the axis of the main pipeline 1, the number is 2-10, and the diameter is 1 / 5-3 / 4 of the main pipeline 1; more preferably, the inner diameter and length of each connecting channel 21 are equal, and the number is 2 or 4.

[0043] According to certain embodiments of the present invention, a gas flow control valve or a gas distributor is provided at the inlet of the gas pipeline 3, and a one-way valve (not shown in the figure) is installed to control the gas flow of each gas pipeline 3 to be equal so that the gas phase is evenly distributed.

[0044] According to some embodiments of the present invention, the connection modes of the liquid phase inlet 11 and the gas-liquid outlet 12 with external equipment include but are not limited to threaded connection or flange connection.

[0045] According to some embodiments of the present invention, Figure 3 As shown, the swirl column 41 is a solid cylinder, coaxially installed at the entrance of the connecting channel 21, the bottom diameter of the cylinder is 1 / 3 to 2 / 3 of the inner diameter of the connecting channel 21, and the length is 1 / 2 to 3 / 4 of the connecting channel 21.

[0046] According to some embodiments of the present invention, Figure 3 As shown, the swirl plates 42 include straight plates and curved plates with different curvatures. The number of swirl plates 42 in each swirl structure 4 is 3 to 10, which are symmetrically and evenly distributed around the axis of the swirl column 41; more preferably, the swirl plates 42 are straight plates and have a circular arc triangle cross-sectional shape, with an angle of 20° to 70° with the horizontal plane, and the number of swirl plates 42 in each swirl structure 4 is 3.

[0047] According to some embodiments of the present invention, Figure 3 As shown, all the swirl plates 42 in the swirl structure 4 are of equal shape and size, and the diameter and length of the swirl column 41 remain consistent; the swirl plates 42 of the swirl structure 4 in the same connecting channel 21 have the same angle direction and size, and the swirl plates 42 of the swirl structure 4 in adjacent connecting channels 21 have the same angle size and opposite direction; thereby ensuring that the swirl intensity of the swirl field in each connecting channel 21 is equivalent, and the rotation direction of the swirl field in adjacent connecting channels 21 is opposite.

[0048] In terms of design concept, the multi-swirl microbubble generator of the present invention innovatively combines the parallel structure and swirl structure of the traditional Venturi microbubble generator. By installing a swirl structure in each connecting channel, the liquid phase flow rate when the gas and liquid phases are in contact is increased, and the orifice shedding and bubble breaking process when the bubble is formed are promoted. The multi-channel parallel connecting structure is adopted. On the one hand, the gas flow is evenly distributed in each connecting channel. On the other hand, after the fluid passes through the multi-channel parallel connecting channel, it converges in the gas-liquid mixing chamber, eliminating the swirl tail flow, reducing the probability of collision and aggregation between bubbles, and the bubble conveying effect is better.

[0049] When the multi-vortex microbubble generator of the present invention is working, the liquid phase flow enters the main pipeline 1 from the liquid phase inlet 11, and is dispersed into multiple streams when flowing through the connecting channel 21. After the liquid flow enters the connecting channel 21, it flows through the vortex structure 4 to generate a tangential flow velocity, and the turbulent kinetic energy of the liquid phase is improved. Then, it contacts the gas phase flow from the gas pipeline 3 on the inner surface of the connecting channel 21 to form bubbles; finally, multiple streams of fluid enter the gas-liquid mixing chamber 13 and converge, eliminating the vortex tail flow, and the gas-liquid two phases are fully mixed.

[0050] Comparative Example 1

[0051] This comparative example adopts Figure 4The Venturi microbubble generator shown includes a liquid phase inlet 31, a convergent section 32, a throat 33, a gas pipeline 34, a divergent section 35 and a gas-liquid outlet 36. The total length of the Venturi microbubble generator is 150 mm, of which the convergent section is 22 mm long, the divergent section is 68 mm long, the throat is 20 mm long, the throat diameter is 8 mm, and the length of the liquid phase inlet and the gas-liquid outlet straight pipe section is 20 mm. The inlet diameter of the convergent section is equal to the outlet diameter of the divergent section, both of which are 26 mm. A circular hole inlet is used, located in the middle of the throat section, the number is 1, and the diameter is 5 mm.

[0052] A nitrogen-water system was used as the simulated experimental medium, and a high-speed camera was used to photograph the bubbles generated by the Venturi microbubble generator. The gas flow rate Q G =0.018m 3 / h, liquid flow rate Q L 0.4, 0.6, 0.8, 1.0, 1.2m respectively 3 / h. The average Souter diameter of bubbles changes with the liquid flow rate as shown in Figure 5 As shown in the figure, it can be seen that as the liquid flow rate Q L As the liquid flow rate Q L =1.0m 3 / h, the average bubble diameter d 32 =1770 microns, and its diameter distribution is 80 microns to 3900 microns.

[0053] Example 1

[0054] This embodiment adopts Figure 1 The multi-swirl microbubble generator shown in the figure prepares bubbles. The diameters of the main pipeline 1 and the gas-liquid mixing chamber 13 are the same, both 26mm; the number of connecting channels is 2, the diameter is 11.5mm, the length is 20mm, and the axis lines of the two connecting channels are 14.5mm apart; the diameter of the swirl column is 7mm, the length is 10mm; the angle between the swirl plate and the horizontal plane is 45°, and the thickness is 2mm. The center of the air inlet is 5mm away from the upper surface of the swirl column, and the diameter is 3.5mm.

[0055] A nitrogen-water system was used as the simulated experimental medium, and a high-speed camera was used to photograph the bubbles generated by the multi-cyclonic microbubble generator. The gas flow rate Q G =0.018m 3 / h, liquid flow rate Q L 0.4, 0.6, 0.8, 1.0, 1.2m respectively 3 / h. The average Souter diameter of bubbles changes with the liquid flow rate as shown in Figure 5 As shown in the figure, it can be seen that as the liquid flow rate Q L With the increase of flow rate, the average Sauter diameter of bubbles is greatly reduced; and except for the flow condition QL =1.2m 3 / h, the average diameter of the bubbles generated by the multi-swirl microbubble generator is smaller than that of the Venturi microbubble generator under the same working conditions; when the liquid flow rate Q L =1.0m 3 / h, the average bubble diameter d 32 =1670 microns, and its diameter distribution is 80 microns to 3700 microns.

[0056] Comparative Example 2

[0057] This comparative example adopts Figure 4 The Venturi microbubble generator shown in the figure has a total length of 160mm, of which the convergent section is 24mm long, the divergent section is 76mm long, the throat is 20mm long, the throat diameter is 6mm, and the length of the straight pipe section of the liquid phase inlet and the gas-liquid outlet is 20mm. The inlet diameter of the convergent section is equal to the outlet diameter of the divergent section, both of which are 26mm. A circular air inlet hole is used, located in the middle of the throat section, the number is 1, and the diameter is 5mm.

[0058] The nitrogen-water system was used as the simulated experimental medium, and the pressure drop of the Venturi microbubble generator was measured using a U-type differential pressure gauge. The gas flow rate Q G =0.018m 3 / h, liquid flow rate Q L 0.4, 0.6, 0.8, 1.0m respectively 3 / h. As the liquid flow rate Q L The pressure drop increases significantly when the liquid flow rate Q L =1.0m 3 / h, the bubble generator pressure drop △P = 28.50kPa.

[0059] Example 2

[0060] The microbubble generator used in this embodiment is the same as that in embodiment 1. A nitrogen-water system is used as the simulated experimental medium, and a U-type differential pressure gauge is used to measure the pressure drop of the multi-cyclone microbubble generator. G =0.018m 3 / h, liquid flow rate Q L 0.4, 0.6, 0.8, 1.0m respectively 3 / h. As the liquid flow rate Q L With the increase of liquid flow rate Q, the pressure drop increases significantly, and the pressure drop of the multi-swirl microbubble generator is smaller than that of the Venturi microbubble generator under the same working conditions; L =1.0m 3 / h, the pressure drop of the microbubble generator △P = 21.92kPa.

[0061] Comparative Example 3

[0062] The microbubble generator used in this comparative example is the same as that used in comparative example 2. Before the experiment, copper sulfate was used as a catalyst and sodium sulfite as a deoxidizer to remove dissolved oxygen in the water to below 2 mg / L. The experiment used a system of water and oxygen, and the gas flow rate Q G =0.018m 3 / h, liquid flow rate Q L 0.4, 0.6, 0.8, 1.0, 1.2m respectively 3 / h, the dissolved oxygen content in the water at the outlet of the bubble generator is monitored in real time by a dissolved oxygen meter, and the dynamic dissolved oxygen response curve method is used to characterize the gas-liquid mass transfer performance of the microbubble generator. L The increase of liquid phase volume mass transfer coefficient k L a increases; when the liquid flow rate Q L =1.2m 3 / h, liquid phase volume mass transfer coefficient k L a=9.94×10 -4 s -1 .

[0063] Example 3

[0064] The microbubble generator used in this embodiment is the same as that in embodiment 1. The experiment uses a water and oxygen system, and the gas flow rate Q G =0.018m 3 / h, liquid flow rate Q L 0.4, 0.6, 0.8, 1.0, 1.2m respectively 3 / h, the deoxygenation treatment method and data processing method are the same as those in Comparative Example 3. L The increase of liquid phase volume mass transfer coefficient k L a increases; and except for the flow condition Q L =0.4m 3 / h, the liquid phase volume mass transfer coefficient of the multi-cyclone microbubble generator is higher than that of the Venturi microbubble generator under the same working conditions; when the liquid flow rate Q L =1.2m 3 / h, liquid phase volume mass transfer coefficient k L a=11.42×10 -4 s -1 .

[0065] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all implementation methods here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A multi-cyclone microbubble generator, characterized in that: It includes a hollow main pipeline, connecting pieces, gas pipelines and swirl structures. The main pipeline includes a liquid phase inlet arranged at the bottom and a gas-liquid outlet arranged at the top; The connecting piece is arranged in the middle section of the main pipeline, dividing the main pipeline into two sections, the upper section and the lower section; the cavity in the upper section of the main pipeline is a gas-liquid mixing cavity, and the cavity in the lower section of the main pipeline is a liquid inlet cavity; The connecting piece is provided with at least one connecting hole, which connects the gas-liquid mixing chamber and the liquid inlet chamber; The swirl structure is arranged at the lower part of the communicating channel and is installed on the inner wall of the communicating channel; the swirl structure comprises a swirl column and a swirl plate; The gas pipeline outlet leads to the connecting hole on the connecting piece, and the gas pipeline outlet is arranged above the swirl structure; The communicating channels are symmetrically and evenly distributed around the axis of the main pipeline, with a number of 2-10 and a diameter of 1 / 5-3 / 4 of the main pipeline; The swirl column is a solid cylinder, which is coaxially installed at the entrance of the connecting channel. The diameter of the bottom surface of the cylinder is 1 / 3 to 2 / 3 of the inner diameter of the connecting channel, and the length is 1 / 2 to 3 / 4 of the connecting channel.

2. The multi-cyclone microbubble generator according to claim 1, characterized in that: The gas-liquid mixing chamber has the same inner diameter as the main pipeline and is coaxially connected.

3. The multi-cyclone microbubble generator according to claim 1, characterized in that: The diameter and length of each communicating channel are equal, and the number of the communicating channels is 2 or 4.

4. The multi-cyclone microbubble generator according to claim 1, characterized in that: A gas flow control valve or a gas distributor is provided at the inlet of the gas pipeline, and a one-way valve is also installed.

5. The multi-cyclone microbubble generator according to claim 1, characterized in that: The liquid phase inlet and the gas-liquid outlet are connected to external equipment by threaded connection or flange connection.

6. The multi-cyclone microbubble generator according to claim 1, characterized in that: The swirl plates include straight plates and curved plates with different curvatures. The number of swirl plates in each swirl structure is 3 to 10, which are symmetrically and evenly distributed around the axis of the swirl column.

7. The multi-cyclone microbubble generator according to claim 6, characterized in that: The swirl plate is a straight plate with a cross-sectional shape of an arc triangle, an angle between the plate and the horizontal plane is 20° to 70°, and the number of swirl plates in each swirl structure is 3.

8. The multi-cyclone microbubble generator according to claim 6, characterized in that: All swirl plates in the swirl structure are of equal shape and size, and the diameter and length of the swirl columns are consistent; the swirl plate angles of the swirl structure in the same connecting channel are of the same direction and size, and the swirl plate angles of the swirl structures in adjacent connecting channels are of the same size and opposite direction.

Images