Composite structure gas-liquid bubbling generator and its application

Abstract

This invention provides a composite gas-liquid bubble generator and its application. The gas-liquid bubble generator has a simple structure, is easy to process, assemble, and install, and can effectively reduce bubble size and significantly improve the size uniformity of micron-sized bubbles. The gas-liquid bubble generator includes a first Venturi structure and a second Venturi structure. The first Venturi structure is used to compress and shear the liquid phase material onto the gas phase material to obtain a first gas-liquid mixture containing microbubbles. The second Venturi structure is connected to the first Venturi structure and is used to further compress and shear the microbubbles in the first gas-liquid mixture to obtain a second gas-liquid mixture. The second Venturi structure includes a bubble cap structure, a hollow second contraction section, and a hollow second expansion section. The bubble cap structure includes a bubble cap shell, within which a flow channel, a buffer space, and an annular channel located around the flow channel are formed.

Description

Technical Field

[0001] This invention relates to a microbubble generator applicable to the chemical industry, particularly to gas-liquid phase reaction systems or gas-liquid phase bubbling mass transfer, and specifically to a composite gas-liquid bubbling generator, a gas-liquid bubbling reaction device, and their applications. Background Technology

[0002] Many gas-liquid phase reactions in the chemical industry, such as hydrogenation, oxidation, carbonylation, alkylation, nitration, halogenation, and rearrangement, are carried out in traditional gas-liquid bubbling reactors. These reactors generally suffer from drawbacks such as long reaction times, large equipment size, high safety risks, and large investment and footprint. These shortcomings are primarily due to the excessively large bubble size in traditional gas-liquid bubbling reactors. At high apparent gas velocities, the rising of large bubbles leads to intense turbulence in the liquid phase, making process control difficult and posing high safety risks. Furthermore, the high degree of gas-liquid phase turbulence results in high energy consumption, leading to excessive investment and footprint. Simultaneously, the large bubble size causes excessively high bubble rising velocities, resulting in insufficient gas phase residence time, excessively long reaction times, and low mass transfer efficiency.

[0003] When bubbles are broken down to the micrometer scale, not only are their size and shape indistinguishable to the naked eye, but their number also increases by tens, hundreds, or even thousands of times, reaching as high as 10 in a unit system. 9 ~10 11 / m 3 Its gas-liquid interface area will also reach 10 3 ~10 5 m 2 / m 3 The scale is on the order of magnitude; while the gas-liquid interface area of ​​a traditional gas-liquid bubbling bed reactor is typically 10. 2 m 2 / m 3 The flow rate is on the order of magnitude. Simultaneously, the gas-liquid reaction system is a relatively gentle, uniform bubbly flow. The smaller the bubble size, the more stable the bubble flow, resulting in a gentler flow system and reduced energy consumption during the flow process. Furthermore, the smaller bubble size reduces the bubble's rising velocity, increasing the gas-liquid phase contact time. The gas-liquid mass transfer and reaction are also more gradual. The gas-liquid bubbling flow is equivalent to multiple microreactors connected in series, allowing for better control of the gas-liquid phase reaction and reducing safety risks during the reaction process. To address the problems of low mass transfer efficiency, difficult process control, and high energy consumption in traditional gas-liquid bubbling devices, a series of microbubble generation and preparation technologies have emerged. Currently, most microbubble generators employ a Venturi structure.

[0004] The solution provided in patent document CN1188208C combines liquid phase vortex technology with Venturi bubble generation technology, which can easily generate fine bubbles on an industrial scale and produce relatively small and simple devices for water purification in ponds, lakes, rivers, and other water bodies. It can also increase the oxygen and dissolved oxygen content in aquaculture and hydroponic solutions, thereby improving the harvest rate. However, the bubble size generated by the above method has a large dispersion (i.e., poor size uniformity), with micron-sized bubbles as well as a large number of millimeter-sized bubbles, which is not conducive to the control of chemical reactions. At the same time, the processing technology is difficult, so it has not been applied and promoted in the chemical industry.

[0005] Patent document CN103041723B discloses a microbubble generator, which is equivalent to two Venturi structures nested together. It is mainly used for aquaculture and sewage treatment. At the same time, it can provide a large number of microbubbles for the liquid in the gas-liquid reaction tank. Due to its complex structure, it has not been studied for chemical reaction under high temperature and high pressure, so it has not been applied to traditional gas-liquid bubbling reaction devices.

[0006] Patent document CN107744732A discloses a tubular microbubble generator with a Venturi structure, coupled with guide vanes and a microporous plate. It integrates microporous bubble generation, Venturi bubble generation, and swirling bubble generation technologies, while simultaneously improving the uniformity of gas phase distribution in the water flow through an annular aerator. The design of the inner annular microporous plate avoids direct erosion between the water flow and the microporous surface, solving the problem of easy pore clogging in microporous bubble generation technology. The coupling of these three technologies improves the shearing and breaking up of bubbles by the water flow. The device has a compact structure, low maintenance costs, and can generate microbubbles of different particle sizes. This device is mainly used in drainage engineering or industrial wastewater purification. However, due to its high manufacturing difficulty and poor bubble size uniformity, it is difficult to control in chemical reactions and has not been widely adopted in the chemical industry.

[0007] Patent document CN109200839A discloses a Venturi microbubble generator, comprising a front diffusion section, a rectification section, a Venturi tube, a transition section, and a rear contraction section connected in sequence. It utilizes the high-speed water flow shear formed when the liquid passes through the throat region of the Venturi tube and the high-intensity eddy current disturbance generated in the gradual diffusion section to generate bubbles with high efficiency, large quantity, and energy saving. It can be applied in the field of water purification and to improve the living environment of fish and aquatic animals. However, due to the poor uniformity of bubble size generated by this method, it is difficult to achieve good control in chemical reactions and has not been applied in the chemical industry.

[0008] Patent document CN109966939A discloses a microbubble generator combining swirling and Venturi bubble generation technologies, and a gas-liquid reactor incorporating the microbubble generator. The microbubble generator mainly comprises a Venturi tube, an inlet, and a swirling device. The Venturi tube includes at least a converging section, a throat section, and a diverging section. A swirling device is installed in the diverging section, and the inlet is located at the throat of the Venturi tube. The swirling device is composed of a spiral internal component, a tangential tube, and a swirling plate. After installing this microbubble generator in the gas-liquid reactor, the residence time of bubbles in the liquid phase increases significantly, the bubble size decreases significantly, the microbubble fraction increases, and the gas-liquid mass transfer efficiency is significantly improved. However, due to differences in the swirling components, the microbubble fraction can range from 58% to 80%, indicating that large bubbles larger than millimeters still exist in the gas-liquid phase, affecting mass transfer.

[0009] Patent document CN111450719A discloses a composite Venturi microbubble generator, comprising a primary Venturi channel and a secondary Venturi channel. After bubbles are broken up in the swirling region of the primary Venturi channel, they are further broken up using the secondary Venturi channel, thus further reducing the bubble size to obtain micron-sized bubbles. Although micron-sized bubbles can be obtained, the gas holdup is low due to the lack of external power. The secondary breaking component has a complex structure, is difficult to manufacture, and the size of the generated bubbles is difficult to control.

[0010] Patent document CN111203142A discloses a micron-sized bubble generator that couples vortex bubble formation, Venturi bubble formation, and ultrasonic technology. After undergoing physical shearing between gas and liquid and secondary ultrasonic stimulation, the micron-sized bubbles become even smaller and more numerous. This micron-sized bubble generator, when applied to the liquid-phase hydrogenation reaction of C3 fractions, can improve the mass transfer efficiency between the liquid phase and hydrogen. However, under the influence of ultrasonic stimulation, microbubbles are also prone to aggregation, affecting bubble size. Furthermore, the presence of an ultrasonic pipe and ultrasonic transducer at the end of the microbubble generator's cylinder increases the difficulty of manufacturing and maintenance.

[0011] The aforementioned patent documents all involve microbubble generators with single or composite Venturi structures. A common problem is that the uniformity of bubble size and the gas phase fraction (i.e., the number of microbubbles per unit volume of liquid) need improvement. Some solutions also suffer from drawbacks such as complex secondary crushing components, making processing / maintenance more difficult. Summary of the Invention

[0012] In view of this, the present invention provides a gas-liquid bubble generator with a composite structure, a gas-liquid bubble reaction device based on the gas-liquid bubble generator, and their applications. The gas-liquid bubble generator provided by the present invention has a simple structure, is easy to process, assemble, and install, can effectively reduce bubble size, and can significantly improve the size uniformity of micron-sized bubbles.

[0013] To achieve its objective, the present invention provides the following technical solution:

[0014] This invention provides a composite gas-liquid bubble generator, comprising a first Venturi structure and a second Venturi structure. The first Venturi structure includes a liquid inlet for introducing liquid material, a gas inlet for introducing gas material, and a first gas-liquid mixture outlet for releasing a first gas-liquid mixture. The first Venturi structure is used to compress and shear the gas material entrained by the gas inlet to obtain a first gas-liquid mixture containing microbubbles. The second Venturi structure is connected to the first Venturi structure and is used to further compress and shear the microbubbles in the first gas-liquid mixture to obtain a second gas-liquid mixture.

[0015] The second Venturi structure includes a bubble cap structure, a hollow second contraction section, and a hollow second expansion section. The inner diameter of the second contraction section gradually decreases from its inlet to its outlet. The inlet of the second contraction section is interconnected with the outlet of the first gas-liquid mixture flow through multiple connecting holes. The second expansion section is fitted around the second contraction section, and the second expansion section has an overall enlarged diameter structure. A second gas-liquid mixture flow outlet for releasing the second gas-liquid mixture flow is provided at the end of the second expansion section with a larger inner diameter. The bubble cap structure is located within the cavity of the second expansion section. The bubble cap structure includes a bubble cap shell, within which a drainage channel, a buffer space, and an annular channel surrounding the drainage channel are formed. The inlet of the drainage channel is connected to the outlet of the second contraction section, and the outlet of the drainage channel is connected to the inlet of the buffer space. The inlet of the annular channel is connected to the outlet of the buffer space, and the outlet of the annular channel is provided with multiple micro-release holes, which are connected to the cavity of the second expansion section.

[0016] In some embodiments, the inner diameter of the drainage channel is less than or equal to the inner diameter of the outlet end of the second contraction section, and the volume of the buffer space is greater than the volumes of the drainage channel and the annular gap channel, respectively.

[0017] Preferably, the volume of the buffer space is 2-6 times the volume of the drainage channel or the annular gap channel.

[0018] In some embodiments, the micro-release pores are provided by providing a porous plate or porous medium at the outlet end of the annular channel; or the micro-release pores are directly formed on the blister housing at a position corresponding to the outlet end of the annular channel; preferably, the equivalent diameter of the micro-release pores is less than 1000 μm.

[0019] And / or, the connecting hole is provided by providing a perforated plate at the junction of the inlet end of the second contraction section and the outlet of the first gas-liquid mixture, or the connecting hole is directly opened on the end face of the second contraction section corresponding to the inlet end of the second contraction section or directly on the end face of the first expansion section corresponding to the outlet of the first gas-liquid mixture; preferably, the equivalent diameter of the connecting hole is 2 to 5 mm.

[0020] In some embodiments, the inner diameter of the annular channel is uniform, or the inner diameter of the annular channel generally decreases from the inlet end to the bottom of the annular channel.

[0021] In some embodiments, the inner diameter of the buffer space gradually decreases from the inlet to the outlet of the drainage channel; the outlet and inlet of the buffer space are located on the same side as the outlet of the drainage channel.

[0022] Preferably, the buffer space is generally conical or approximately conical; or, the buffer space is generally trapezoidal or approximately trapezoidal.

[0023] In some embodiments, the outlet end of the annular channel is located at or near the bottom of the annular channel.

[0024] In some embodiments, the second contraction section and the second expansion section are arranged coaxially;

[0025] Preferably, on the cross section formed along the central axis of the second venturi structure, the first included angle formed between the contour lines of the sidewalls of the second contraction section is 15 to 45°, more preferably 20 to 30°.

[0026] On the cross section formed along the central axis of the second Venturi structure, the second included angle formed between the outline of the sidewall of the second contraction section and the outline of the sidewall of the second expansion section is 15 to 45°, preferably 20 to 30°.

[0027] More preferably, the first included angle and the second included angle are equal.

[0028] In some embodiments, the first Venturi structure includes a hollow first contraction section, a gas-liquid mixing section, and a first expansion section;

[0029] The first contraction section is provided with a liquid phase inlet and a liquid phase outlet, and the inner diameter of the first contraction section gradually decreases from the liquid phase inlet to the liquid phase outlet.

[0030] The first expansion section is provided with a gas-liquid inlet and a first gas-liquid mixture outlet. From the gas-liquid inlet to the first gas-liquid mixture outlet, the inner diameter of the second expansion section gradually increases.

[0031] The gas-liquid mixing section has a liquid inlet and a gas-liquid outlet at each end. The liquid inlet is connected to the liquid phase outlet of the first contraction section, and the gas-liquid outlet is connected to the gas-liquid inlet of the first expansion section. The gas phase inlet is located on the side wall of the gas-liquid mixing section.

[0032] A gas phase inlet pipe is connected to the gas phase inlet.

[0033] In some embodiments, the ratio of the cross-sectional area of ​​the liquid phase inlet of the first contraction section to the liquid inlet of the gas-liquid mixing section is 8:1 to 2:1, preferably 6:1 to 3:1;

[0034] The ratio of the cross-sectional area of ​​the end face of the first expansion section where the first gas-liquid mixture outlet is located to the cross-sectional area of ​​the gas-liquid mixture outlet of the gas-liquid mixing section is 6:1 to 2:1, preferably 3.0:1 to 1.5:1.

[0035] In some embodiments, the ratio of the inner diameter to the length of the gas phase inlet pipe is 0.01 to 0.1, preferably 0.01 to 0.05.

[0036] In some embodiments, in the first Venturi structure, the volume of the first contraction section is greater than the volume of the first expansion section;

[0037] The volume of the second expansion section is greater than the volume of the first contraction section, and the volume of the second contraction section is less than the volume of the first contraction section.

[0038] In some embodiments, the first contraction section, the gas-liquid mixing section, the first expansion section, the second contraction section, the bubble structure, and the second expansion section are arranged coaxially.

[0039] The present invention also provides a gas-liquid bubbling reaction device, including a tower body, wherein a reaction chamber and a gas chamber are provided in the inner cavity of the tower body, and a gas phase inlet and a liquid phase inlet are provided on the tower body;

[0040] The gas-liquid bubbling device described above is installed in the gas chamber;

[0041] The gas phase inlet of the gas-liquid bubbling generator is connected to the gas phase feed port, the liquid phase inlet of the gas-liquid bubbling generator is connected to the liquid phase feed port, and the second gas-liquid mixed outlet of the gas-liquid bubbling generator is connected to the reaction chamber.

[0042] In some embodiments, a gas-liquid distribution plate is provided between the gas chamber and the reaction chamber, and the gas-liquid distribution plate has distribution holes for connecting the gas chamber and the reaction chamber. The second gas-liquid mixing outlet of the gas-liquid bubbling device corresponds to the position of the distribution holes of the gas-liquid distribution plate and is connected to each other.

[0043] Preferably, the number of gas-liquid bubbling generators is the same as the number of distribution holes in the gas-liquid distribution plate;

[0044] Preferably, the porosity of the distribution holes on the gas-liquid distribution plate is 0.3% to 0.7%, more preferably 0.3% to 0.5%.

[0045] The present invention also provides an application in which the gas-liquid bubbling generator or the gas-liquid bubbling reaction device described above is applied to a gas-liquid phase reaction system or a gas-liquid phase bubbling mass transfer system.

[0046] In some embodiments, the apparent gas velocity at the gas phase inlet of the gas-liquid bubbling reactor is greater than 0.01 m / s, the liquid phase material flow velocity at the liquid phase inlet of the gas-liquid bubbling reactor is greater than 0.1 m / s, and the Reynolds number Re in the annular channel of the bubble cap structure is not less than 5000.

[0047] The ratio of the liquid phase volumetric flow rate at the liquid inlet to the gas phase volumetric flow rate at the gas phase inlet of the gas-liquid bubbling reaction device is 1 to 100, preferably 20 to 70.

[0048] The technical solution provided by this invention has the following beneficial effects:

[0049] The composite gas-liquid bubble generator provided by this invention can obtain small and highly uniform microbubbles from gaseous and liquid materials. Furthermore, this gas-liquid bubble generator has a simple structure, is easy to assemble, and can be easily arranged in a gas-liquid bubble reaction device as needed. Applying the gas-liquid bubble reaction device provided by this invention to a gas-liquid bubble reaction device, compared with traditional gas-liquid bubble reaction devices, can provide small and highly uniform microbubbles and contribute to increasing the gas content in the gas-liquid mixture. In gas-liquid two-phase reaction systems and in gas-liquid bubble mass transfer, the gas-liquid bubble generator of this invention can obtain small and highly uniform microbubbles, effectively increasing the gas-liquid phase contact area. The highly uniform micron-sized bubbles prolong the gas-liquid phase contact time and increase the residence time of the gas phase, which is beneficial for enhancing mass transfer and reaction. Using the gas-liquid bubbling generator of the present invention in a gas-liquid bubbling reaction device helps to solve the problems of poor bubble size uniformity, low mass transfer efficiency, and high energy consumption of the current gas-liquid bubbling reaction device. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of a composite gas-liquid bubbling generator in one embodiment.

[0051] Figure 2 for Figure 1 A schematic diagram of the gas-liquid bubbling generator in the diagram;

[0052] Figure 3 This is a schematic diagram of a blister structure in one embodiment;

[0053] Figure 4 This is a schematic diagram of a blister structure in another embodiment;

[0054] Figure 5 This is a schematic diagram of the blister structure in another embodiment;

[0055] Figure 6 This is a schematic diagram of a gas-liquid bubbling reaction device in one embodiment.

[0056] Figure 7 This is a schematic diagram showing the arrangement of multiple gas-liquid bubbling generators in a gas-liquid bubbling reaction device according to one embodiment. Detailed Implementation

[0057] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0059] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this document are defined relative to the structures shown in the accompanying drawings. These are relative concepts and may therefore vary depending on their location and usage. The terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0060] This invention provides a composite structure gas-liquid bubbling generator. The following will combine... Figure 1-5 An exemplary description is provided for a gas-liquid bubbling generator with a composite structure, wherein... Figure 2 and Figure 1 The only difference is the marking in different locations, to facilitate clear display and description. Figure 1 The gas-liquid bubbling generator shown. See also... Figure 1-3 The gas-liquid bubbling generator 100 mainly includes a first Venturi structure 200 and a second Venturi structure 300. The first Venturi structure 200 includes a liquid inlet 11 for introducing liquid material, a gas inlet 21 for introducing gaseous material, and a first gas-liquid mixture outlet 32. The first Venturi structure 200 is used to compress and shear the gaseous material entrained by the gas inlet 21, thereby obtaining a first gas-liquid mixture containing microbubbles. The first gas-liquid mixture containing microbubbles is released into the second Venturi structure 300 through the first gas-liquid mixture outlet 32. The second Venturi structure 300 can further compress and shear the microbubbles in the first gas-liquid mixture released from the first Venturi structure 200, thereby obtaining a second gas-liquid mixture. The second gas-liquid mixture is released downstream through the second gas-liquid mixture outlet 61 of the second Venturi structure 300, for example, into the reaction chamber of the gas-liquid bubbling reactor.

[0061] The second Venturi structure 300 mainly includes a bubble structure 7, a hollow second contraction section 5, and a hollow second expansion section 6.

[0062] The second contraction section 5 has an inlet end 51 and an outlet end 52. The second contraction section 5 has a tapered diameter overall. Specifically, the inner diameter of the second contraction section 5 gradually decreases from the inlet end 51 to the outlet end 52. The inlet end 51 of the second contraction section 5 is interconnected with the first gas-liquid mixture outlet 32 ​​of the first Venturi structure 200 through multiple connecting holes (not shown in the figure). Specifically, the first gas-liquid mixture containing microbubbles released from the first gas-liquid mixture outlet 32 ​​of the first Venturi structure 200 first enters the second contraction section 5 through the connecting holes.

[0063] The second expansion section 6 is fitted around the second contraction section 5. The second expansion section 6 has an enlarged diameter structure, and a second gas-liquid mixture outlet 61 is provided at the end with the larger inner diameter of the second expansion section 6. The second gas-liquid mixture obtained in the second Venturi structure 300 is released through this second gas-liquid mixture outlet 61. Preferably, the end with the smaller inner diameter of the second expansion section 6 is connected to the end with the larger inner diameter of the second contraction section 5 (i.e., the inlet end 51 of the second contraction section 5), and the second contraction section 5 is located entirely within the cavity of the second expansion section 6.

[0064] The bubble structure 7 is located within the cavity of the second expansion section 6. See also... Figure 3 The bubble cap structure 7 includes a bubble cap shell 74, within which a flow channel 71, a buffer space 72, and an annular channel 73 are formed. The annular channel 73 is located around the flow channel 71. The inlet of the flow channel 71 is connected to the outlet end 52 of the second contraction section 5, and the outlet of the flow channel 71 is connected to the inlet of the buffer space 72. The inlet end of the annular channel 73 is connected to the outlet of the buffer space 72, and the outlet end 75 of the annular channel 73 is provided with multiple micro-release holes (not shown in the figure), which are connected to the inner cavity of the second expansion section 6. That is, the bubble cap structure 7 is connected to the outlet end 52 of the second contraction section 5 through the flow channel 71, so that the first gas-liquid mixture flows through the second contraction section 5 and enters the bubble cap structure 7, and flows sequentially through the flow channel 71, the buffer space 72, and the annular channel 73.

[0065] When the first gas-liquid mixture released from the first Venturi structure 200 passes through the inlet end 51 of the second contraction section 5 and enters the second contraction section 5 through multiple connecting holes at the interface between the first gas-liquid mixture outlet and the second contraction section, the bubbles in the gas-liquid mixture are compressed and sheared, and the bubble size is further reduced. The gas-liquid mixture continues to flow in the second contraction section 5 of the narrow diameter structure, and then enters the guide channel 71 in the bubble cap structure 7. During the flow, the bubbles are compressed and sheared. Subsequently, it continues to enter the buffer space 72 and changes its flow direction under the guidance of the annular channel 73. After entering the narrow annular channel 73, it continues to be compressed and sheared. Then, it flows out through multiple micro-release holes at the outlet end 75 of the annular channel 73 and enters the second expansion section 6. When it flows through the multiple micro-release holes at the outlet end 75 of the annular channel 73, the bubbles are further sheared, and finally the second gas-liquid mixture is obtained. During the flow of the gas-liquid mixture through the bubble cap structure 7, the specific flow channel structure formed by the combination of the flow channel 71, the buffer space 72, and the annular channel 73 within the bubble cap structure 7 can effectively reduce the pressure fluctuations caused by the front-end Venturi structure, thus achieving a pressure stabilization effect. The gas-liquid bubbling generator provided by this invention has a simple structure, is easy to process and assemble, does not involve complex structures, and by configuring the gas-liquid bubbling generator provided by this invention in the gas-liquid bubbling reaction device, micron-sized bubbles with improved size uniformity can be obtained, making it easy to increase the gas content.

[0066] Furthermore, in the second Venturi structure 300, the inner diameter of the drainage channel 71 in the bubble cap structure 7 is less than or equal to the inner diameter of the outlet end 52 of the second contraction section 5, and the volume of the buffer space 72 is greater than the volume of the drainage channel 71 and the volume of the annular channel 73, respectively. This helps to achieve a strengthened compression and shearing effect in the gas-liquid mixture within the second Venturi structure 300, while also helping to better reduce pressure fluctuations caused by the front-end Venturi structure. Preferably, the volume of the buffer space 72 is 2-6 times the volume of the drainage channel 71 or the annular channel 73; more preferably, the volume of the buffer space 72 is 2-4 times the volume of the drainage channel 71 or the annular channel 73. Using the preferred volume ratio is beneficial for further improving the compression and shearing effect of the bubbles. In some preferred embodiments, the inner diameter of the drainage channel 71 is equal to the inner diameter of the outlet end 52 of the second contraction section 5. Specifically, the drainage channel 71 can be a straight pipe channel.

[0067] In some embodiments, a porous plate or porous medium is provided at the outlet end 75 of the annular channel 73 to provide micro-release pores communicating with the inner cavity of the second expansion section 6. Specifically, the micro-release pores are provided through through-holes in the porous plate or porous medium. For example, the outlet end 75 is open, and a porous plate or porous medium is installed thereon, providing micro-release pores through the holes in the porous plate or porous medium. Porous media include, but are not limited to, porous media materials such as ceramics or porous materials of sintered metals. The gas-liquid mixture flowing within the annular channel 73 enters the inner cavity of the second expansion section 6 through the through-holes in the porous plate or porous medium, and is then released outward from the second gas-liquid mixture outlet 61 on the second expansion section 6. In practical applications, the size of bubbles in the gas-liquid mixture can be controlled by adjusting the pore size and number of micro-orifices at the outlet end 75 of the annular channel 73. For example, the pore size and number of micro-orifices can be flexibly adjusted by selecting a porous plate with a target pore size or a porous medium that meets the target pore size requirement. Preferably, the equivalent diameter of the micro-orifices is less than 1000 μm. The gas-liquid mixture undergoes further compression and shearing as it flows through the porous plate or porous medium at the outlet end 75 of the annular channel 73. Specifically, the outlet end 75 of the annular channel 73 can be located at the bottom of the annular channel 73 or near the bottom of the annular channel 73, such as on the sidewall of the annular channel near the bottom of the annular channel 73. Figure 1 In the illustrated blister structure, the outlet end 75 of the annular channel 73 is located at the bottom of the annular channel 73. There are no particular limitations on the shape of the micro-orifice; it can be circular, triangular, square, rectangular, etc. Specifically, a micro-orifice of the desired diameter can also be directly formed on the blister shell at the position corresponding to the outlet end 75 of the annular channel 73.

[0068] In some embodiments, a perforated plate is provided at the junction of the inlet end 51 of the second contraction section 5 and the outlet 32 ​​of the first gas-liquid mixture to provide a connecting hole between the two; that is, the openings on the perforated plate serve as connecting holes; that is, the first gas-liquid mixture flows through the perforated plate and then enters the second contraction section 5. Preferably, the equivalent diameter of the connecting hole is 2 to 5 mm. The perforated plate mentioned herein includes various plates with multiple holes, including perforated plates, etc. Specifically, the shape of the connecting hole is not particularly limited; for example, it can be at least one of a circle, triangle, square, or rectangle. The arrangement of the multiple connecting holes is not particularly limited; for example, it can be a triangular arrangement, a square arrangement, or a uniform distribution, etc. In some embodiments, the number of connecting holes is 3 to 6. In some embodiments, multiple through holes can also be directly opened on the end face of the second contraction section 5 corresponding to the inlet end 51 of the second contraction section, or multiple through holes can be directly opened on the end face of the first expansion section 3 corresponding to the outlet 32 ​​of the first gas-liquid mixture; these through holes serve as connecting holes to connect the first expansion section 3 and the second contraction section 5.

[0069] In some embodiments, the inner diameter of the annular channel 73 is uniform, such as... Figure 3 As shown. In some implementations, such as Figure 4 , 5 As shown, from the inlet end of the annular channel 73 to the bottom of the annular channel 73, the inner diameter of the annular channel 73 generally decreases. This gradual change in the flow path makes the flow more gentle, which helps to reduce energy loss during the flow process. The inner wall profile of the annular channel 73 is not particularly limited; for example, it can be arc-shaped (e.g., ...). Figure 5 As shown), it is either straight, or straight with a bend (such as...). Figure 3 , 4 (As shown).

[0070] In some preferred embodiments, the inner diameter of the buffer space 72 gradually decreases from the inlet to the outlet of the drainage channel 71; the outlet and inlet of the buffer space 72 are located on the same side as the outlet of the drainage channel 71. Specifically, as shown... Figure 1-5 As shown, the outlet of the buffer space 72 surrounds the periphery of the outlet of the drainage channel 71. In some preferred embodiments, such as... Figure 3 As shown, the buffer space 72 is generally conical or roughly conical; or, as Figure 4 , 5 As shown, the buffer space 72 is generally trapezoidal or roughly trapezoidal. In some specific configurations, such as... Figure 3 As shown, the blister pack shell is generally conical or roughly conical. In some specific configurations, such as... Figure 4 , 5 As shown, the blister pack shell is generally trapezoidal or roughly trapezoidal in shape.

[0071] Better, such as Figure 1 As shown, the second contraction section 5 and the second expansion section 6 are arranged coaxially. Preferably, as... Figure 1 As shown, on the cross-section formed by the central axis of the second Venturi structure 300, the first included angle γ formed between the contour lines of the sidewalls of the second contraction section 5 is 15~45°, preferably 20~30°, and the second included angles α and β formed between the contour lines of the sidewalls of the second contraction section 5 and the sidewalls of the second expansion section 6 are 15~45°, preferably 20~30°. This preferred angle design enhances the compression and shearing effect of the second Venturi structure 300 on the bubbles in the gas-liquid mixture, thereby facilitating the acquisition of microbubbles with further reduced size and better size uniformity. More preferably, the first and second included angles are equal, i.e., α, β, and γ are equal; this not only improves the compression and shearing effect of the bubbles but also simplifies the processing and assembly of the second Venturi structure 300.

[0072] In some embodiments, the first Venturi structure 200 mainly includes a hollow first contraction section 1, a gas-liquid mixing section 2, and a first expansion section 3. The first contraction section 1 has a liquid inlet 11 and a liquid outlet 12. From the liquid inlet 11 to the liquid outlet 12, the inner diameter of the first contraction section 1 gradually decreases, meaning the first contraction section 1 has an overall contraction diameter structure. The first expansion section 3 has a gas-liquid inlet 31 and a first gas-liquid mixing outlet 32. From the gas-liquid inlet 31 to the first gas-liquid mixing outlet 32, the inner diameter of the first expansion section 3 gradually increases, meaning the first expansion section 3 has an overall expansion diameter structure. The gas-liquid mixing section 2 has a liquid inlet 22 and a gas-liquid outlet 23 at its two ends. The liquid inlet 22 is connected to the liquid outlet 12 of the first contraction section 1, and the gas-liquid outlet 23 is connected to the gas-liquid inlet 31 of the first expansion section 3. The gas inlet 21 is located on the side wall of the gas-liquid mixing section 2, and a gas inlet pipe 4 is connected to the gas inlet 21. During application, liquid material at a certain flow rate enters the first contraction section 1 through the liquid inlet 11, then enters the gas-liquid mixing section 2 through the liquid outlet 12, then enters the first expansion section 3, and then enters the subsequent second Venturi structure 300. During the flow of the liquid material, a negative pressure is formed in the gas-liquid mixing section 2. External gas material, under the influence of this negative pressure, is drawn into the gas-liquid mixing section 2 through the gas inlet 21 via the gas inlet pipe 4. There, it is squeezed and sheared by the liquid material flowing at a certain speed, generating microbubbles and obtaining a first gas-liquid mixed flow containing microbubbles. This first gas-liquid mixed flow is released through the first expansion section 3 to the second Venturi structure 300, and then flows towards the second Venturi structure 300. During the process, when the gas-liquid mixture flows to the junction of the inlet end 51 of the second contraction section 5 and the outlet of the first gas-liquid mixture of the first expansion section 3, it flows into the second contraction section 5 through multiple connecting holes at that point, where the bubbles are subjected to compression and shearing. Then, it continues to flow in the second contraction section of the narrowing structure, and then sequentially enters the drainage channel 71, buffer space 72 and annular channel 73 in the bubble cap structure 7, and flows into the second expansion section 6 through multiple micro-release holes at the outlet end 75 of the annular channel 73. During the entire flow process of the gas-liquid mixture in the specific channel path, the bubbles in the gas-liquid mixture undergo multiple compression and shearing actions, and the bubble size is greatly reduced and uniform, ultimately resulting in microbubbles with significantly improved size uniformity.

[0073] In a preferred embodiment, the ratio of the cross-sectional area of ​​the liquid inlet 11 of the first contraction section 1 to the liquid inlet 22 of the gas-liquid mixing section 2 is 8:1 to 2:1, preferably 6:1 to 3:1; the ratio of the cross-sectional area of ​​the end face of the first gas-liquid mixing outlet 32 ​​on the first expansion section 3 to the gas-liquid outlet 23 of the gas-liquid mixing section 2 is 6:1 to 2:1, preferably 3.0:1 to 1.5:1. This preferred structural design enhances the extrusion and shearing effect of the bubbles, facilitating the production of small-sized microbubbles with improved uniformity.

[0074] In some preferred embodiments, the ratio of the inner diameter to the length of the gas phase inlet pipe 4 is 0.01 to 0.1, preferably 0.01 to 0.05; in some embodiments, the inner diameter of the gas phase inlet pipe 4 is 1 to 10 mm, preferably 1 to 6 mm, and the length of the gas phase inlet pipe 4 is 3 to 8 cm, preferably 4 to 6 cm; using a gas phase inlet pipe with a preferred length-to-diameter ratio allows the gas to be better drawn into the bubble generating assembly through negative pressure.

[0075] Furthermore, in the first Venturi structure 200, the volume of the first contraction section 1 is greater than the volume of the first expansion section 3, the volume of the gas-liquid mixing section 2 is the smallest, the volume of the second expansion section 6 is greater than the volume of the first contraction section 1, and the volume of the second contraction section 5 is less than the volume of the first contraction section 1.

[0076] Preferably, the first contraction section 1, the gas-liquid mixing section 2, the first expansion section 3, the second contraction section 5, the bubble structure 7, and the second expansion section 6 are arranged coaxially. In some specific embodiments, the central axis of the bubble structure 7 is located on the central axis of the drainage channel 71.

[0077] The gas-liquid bubble generator 100 with the above-mentioned composite structure provided by the present invention is particularly suitable for application in gas-liquid reaction systems or gas-liquid phase bubble mass transfer. Based on the gas-liquid bubble generator 100 of the present invention, small-sized and highly uniform microbubbles can be obtained from gas and liquid phase materials. Moreover, the gas-liquid bubble generator has a simple structure and is easy to install, and the required number of gas-liquid bubble generators can be easily arranged in the gas-liquid bubble reaction device as needed. Based on the gas-liquid bubble reaction device of the present invention, the gas content can be easily increased. In gas-liquid two-phase reaction systems and gas-liquid bubble mass transfer, the gas-liquid bubble generator of the present invention can obtain small-sized and highly uniform microbubbles, effectively increasing the gas-liquid phase contact area. The highly uniform micron-sized bubbles prolong the gas-liquid phase contact time and increase the residence time of the gas phase, which is beneficial to achieving the purpose of enhancing mass transfer and reaction.

[0078] The present invention also provides a gas-liquid bubbling reaction device 400 based on the gas-liquid bubbling generator 100 with the above-mentioned composite structure provided by the present invention. The gas-liquid bubbling reaction device 400 is equipped with the gas-liquid bubbling generator 100 with the above-mentioned composite structure provided by the present invention. Specifically, the gas-liquid bubbling reaction device 400 includes a tower body 404, with a reaction chamber 410 and a gas chamber 403 disposed within the inner cavity of the tower body 404. The tower body 404 is provided with a gas phase inlet 402 and a liquid phase inlet 401; the gas-liquid bubbling generator 100 is installed in the gas chamber 403. The gas phase inlet 21 of the gas-liquid bubbling generator 100 is connected to the gas phase inlet 402, the liquid phase inlet 11 of the gas-liquid bubbling generator is connected to the liquid phase inlet 401, and the second gas-liquid mixed outlet 61 of the gas-liquid bubbling generator is connected to the reaction chamber 410. The gas-liquid bubbling reaction device 400 is provided with a reaction chamber outlet 405.

[0079] More specifically, a gas-liquid distribution plate 408 is provided between the gas chamber 403 and the reaction chamber 410. The gas-liquid distribution plate 408 has distribution holes (not shown in the figure) for connecting the gas chamber 403 and the reaction chamber 410. The second gas-liquid mixing outlet 61 of the gas-liquid bubbling generator 100 corresponds to the position of the distribution holes in the gas-liquid distribution plate 408. The number of gas-liquid bubbling generators 100 arranged in the gas chamber 403 can be flexibly adjusted and determined according to actual needs. The gas phase distribution can be adjusted by changing the number of gas-liquid bubbling generators 100, thereby easily adjusting the specific gas content required in the gas-liquid reaction system according to requirements. When multiple gas-liquid bubbling generators 100 are provided, there are no particular restrictions on the arrangement of the multiple gas-liquid bubbling generators 100 in the gas chamber. For example, they can be evenly distributed or arranged in a specific shape, such as a square or triangular shape. Figure 7 The diagram shown is a cross-sectional view of multiple gas-liquid bubbling devices 100 arranged in a square shape within the gas chamber 403. Figure 7 The dashed line in the figure shows a square unit 500 composed of four gas-liquid bubbling generators 100. Preferably, the number of gas-liquid bubbling generators 100 is consistent with the number of distribution holes on the gas-liquid distribution plate 408; preferably, the opening ratio of the distribution holes on the gas-liquid distribution plate 408 is 0.3% to 0.7%, more preferably 0.3% to 0.5%. Specifically, the gas-liquid distribution plate 408 is provided at the top of the gas chamber 403, and another mounting plate 409 is provided at the bottom. The mounting plate 409 has multiple mounting holes (not shown in the figure). The liquid phase inlet 11 of the gas-liquid bubbling generator 100 corresponds to the position of the mounting holes. The gas-liquid bubbling generator is detachably installed between the gas-liquid distribution plate 408 and the mounting plate 409.

[0080] The parts of the gas-liquid bubbling reaction device that are not further described are all conventional structures of gas-liquid bubbling reaction devices in this field, and will not be described in detail here.

[0081] This invention also provides an application in which the gas-liquid bubbling generator 100 or the gas-liquid bubbling reaction device 400 described above is applied to a gas-liquid reaction system or a gas-liquid phase bubbling mass transfer system. In a preferred embodiment, the apparent gas velocity inside the gas inlet 402 of the gas-liquid bubbling reaction device 400 is greater than 0.01 m / s, the liquid phase material flow velocity at the liquid inlet 401 of the gas-liquid bubbling reaction device 400 is greater than 0.1 m / s, and the Reynolds number Re in the annular channel of the bubble cap structure 7 is not less than 5000; the liquid phase volumetric flow rate at the liquid inlet 401 of the gas-liquid bubbling reaction device 400 is 1 to 100 times, preferably 20 to 50 times, the gas phase volumetric flow rate at the gas inlet 402.

[0082] In the application of the above-mentioned gas-liquid bubbling reaction device 400, liquid phase material is introduced into the inner cavity of the gas-liquid bubbling reaction device through the liquid phase inlet 401, and then enters the first contraction section 1 through the liquid phase inlet 11 of the gas-liquid bubbling generator, and flows sequentially into the subsequent channels; gas phase material is introduced into the gas chamber 403 through the gas phase inlet 402, and due to the high-speed negative pressure formed by the liquid phase material during the flow of the gas-liquid bubbling generator 100, the gas phase material is entrained into the gas phase inlet pipe 4, and enters the gas-liquid mixing section 2 through the gas phase inlet 21; the liquid phase material is squeezed and sheared by the flowing liquid phase material, forming initial microbubbles in the first expansion section 3, resulting in a first gas-liquid mixed flow containing microbubbles. The first gas-liquid mixture released from the first expansion section 3 first flows through the interface between the second contraction section 5 and the first expansion section 3. As it flows through the multiple connecting holes at this point, the bubbles are subjected to compression and shearing, further reducing their size. Then, it flows into the guide channel 71 of the bubble cap structure 7, continuing to flow under the guidance of the guide channel 71 and entering the buffer space 72, and then from the buffer space 72 into the annular channel 73 surrounding the guide channel 71. During this process, the bubbles are further subjected to compression and shearing from the liquid phase, further reducing their size. Simultaneously, under the action of the buffer space 72, the pressure fluctuations caused by the front-end Venturi structure are reduced, achieving a pressure stabilization effect. Afterward, the gas-liquid mixture flows through multiple micro-release holes at the outlet end 75 of the annular channel 73 and is released into the second expansion section 6. During the flow through the micro-release holes, the bubbles are subjected to further shearing and compression. This process yields the second gas-liquid mixture, which is released from the second gas-liquid mixture outlet 61 of the second expansion section 6 into the reaction chamber 410.

[0083] The gas-liquid bubbling generator provided by this invention adopts a Venturi composite bubble cap structure for use in gas-liquid bubbling reaction devices. It effectively solves the problems of low bubble size uniformity, low mass transfer efficiency, and high energy consumption in current gas-liquid bubbling reaction devices. Furthermore, it can be better applied in gas-liquid bubbling reaction devices, optimizing the gas-liquid bubbling reaction process to a certain extent. In addition, this composite structure is easy to process and assemble, convenient and flexible to install, and simple and convenient to maintain and replace.

[0084] The present invention will be further illustrated by the following examples.

[0085] The following descriptions of the detection methods are as follows:

[0086] The total gas holdup in the gas-liquid mixture of the reaction chamber: The total gas holdup in the gas-liquid mixture of the reaction chamber was determined according to the bed collapse method reported in references [1] and [2] listed below. The specific operation method is as follows: when the bubble column is running stably, the dynamic liquid level height of the reaction chamber is recorded. H d Therefore, the total gas-liquid volume in the reaction chamber during operation can be calculated. V d Then, quickly cut off the gas and liquid feed. As the gas escapes, the bed height decreases accordingly. After stabilization, record the static liquid level height. H s Then calculate the liquid volume in the reaction chamber. V s The total gas holdup in the gas-liquid mixture of the reaction chamber can then be calculated. The calculation formula is as follows:

[0087] 100%

[0088] Literature [1]: Guan X, Gao Y, Tian Z, Wang L, Cheng Y, Li X. Hydrodynamics in bubblecolumns with pin-fin tube internals[J]. Chemical Engineering Research&Design, 2015, 102: 196-206.

[0089] Literature[2]: Guan X, Yang N, Li Z, Wang L, Cheng Y, Li

[0090] Example 1

[0091] This embodiment uses, as follows: Figure 6 The diagram shows a gas-liquid bubbling reaction device equipped with a composite structure gas-liquid bubbling generator. A schematic diagram of the composite structure gas-liquid bubbling generator is shown below. Figure 1 See the schematic diagram of the blister structure. Figure 3 The structural descriptions of the gas-liquid bubbling generator and the gas-liquid bubbling reaction device are not specifically mentioned here, and will be referred to in the previous descriptions.

[0092] In this embodiment, the opening ratio of the distribution holes on the gas-liquid distribution plate 408 in the gas-liquid bubbling reaction device 400 is approximately 0.4%. Eight gas-liquid bubbling generators 100 are installed in the gas chamber 403, and the arrangement of each gas-liquid bubbling generator 100 is square. (See reference [reference needed] for details.) Figure 6 The arrangement is done in the same way, except that the number is reduced to 8.

[0093] Along the central axis of the gas-liquid bubbling generator 100, the total length of the gas-liquid bubbling generator 100 is 200 mm. The length of the first contraction section 1 is 80 mm, the length of the first expansion section 3 is 20 mm, the length of the second expansion section 6 is 90 mm, the length of the gas-liquid mixing section 2 is 10 mm, and the length of the bubble cap structure 7 is 50 mm. The gas phase inlet pipe 4 is a circular pipe, one in number, with a diameter of 3 mm and a length of 3 cm. The diameter of the liquid phase inlet 11 is 40 mm, the diameter of the gas-liquid mixing section 2 is 20 mm, and the ratio of the cross-sectional area of ​​the liquid phase inlet 11 to the inlet 22 of the gas-liquid mixing section is 4:1. The ratio of the cross-sectional area of ​​the end face of the first gas-liquid mixing outlet 32 ​​on the first expansion section to the cross-sectional area of ​​the gas-liquid mixing outlet 23 of the gas-liquid mixing section is 4:1. The volume of the buffer space 72 is approximately three times the volume of the drainage channel 71, and the volume of the buffer space 72 is approximately three times the volume of the annular channel 73.

[0094] On the cross section formed along the central axis of the second Venturi structure 300, the first included angle γ formed between the contour lines of the sidewalls of the second contraction section 5 is 30°, and the second included angles α and β formed between the contour lines of the sidewalls of the second contraction section 5 and the sidewalls of the second expansion section 6 are both 30°.

[0095] A perforated plate is provided at the junction of the inlet end 51 of the second contraction section 5 and the first gas-liquid mixture outlet 32 ​​of the first expansion section 3. The openings on the perforated plate serve as connecting holes between the second contraction section 5 and the first expansion section 3. The connecting holes are circular holes with a diameter of 5 mm, and there are 3 of them, arranged in a triangular pattern. The micro-release holes opened at the outlet end 75 of the annular channel 73 of the bubble cap structure 7 are circular holes with an equivalent diameter of 0.5 mm.

[0096] An air-water system was used as the experimental medium for simulation.

[0097] The flow rate is 20 m 3 Water at a flow rate of 0.3 m³ / h is introduced from the liquid inlet 401 of the bubbling reactor 400 and enters the first contraction section 1 through the liquid inlet 11 of the gas-liquid bubbling generator 100. 3 Compressed air at a rate of / h enters the gas chamber 403 from the gas phase inlet 402 of the bubbling reactor. As water flows through the gas-liquid bubbling generator 100, a negative pressure is created in the gas-liquid mixing section 2, causing air to be drawn into the gas phase inlet pipe 4 and then into the gas-liquid mixing section 2 via the gas phase inlet 21. In the gas-liquid mixing section 2, the gas phase is subjected to compression and shearing by the liquid phase, forming initial microbubbles in the first expansion section 3. When the first gas-liquid mixture containing microbubbles exits from the first Venturi structure 200 passes through the interface formed by the porous plate between the first expansion section 3 and the second contraction section 5, it is subjected to compression and shearing, causing the bubble size to decrease. The flow decreases in size, then continues in the second contraction section 5. The gas-liquid mixture containing microbubbles then enters the flow channel 71 of the bubble cap structure 7 at the outlet 52 of the second contraction section 5, and flows sequentially into the buffer space 72 and the annular channel 73. During the flow in each channel of the bubble cap structure 7, the bubbles are subjected to compression and shearing from the liquid phase, further reducing the bubble size. The gas-liquid mixture then flows out from multiple micro-release holes on the outlet 75 of the annular channel 73, enters the second expansion section 6, and is released through the second gas-liquid mixture outlet 61 of the second expansion section 6 into the reaction chamber 410 of the gas-liquid bubbling reactor 400. During implementation, the apparent gas velocity at the gas phase inlet of the gas-liquid bubbling reactor is 0.02 m / s, the liquid phase material flow velocity at the liquid phase inlet of the gas-liquid bubbling reactor is 0.2 m / s, and the Reynolds number Re in the annular channel of the bubble cap structure is 5500.

[0098] Through testing, the total gas content in the gas-liquid mixing system in the reaction chamber of this embodiment is 50%. The size distribution of bubbles in the gas-liquid mixing system in the reaction chamber is detected by a particle size analyzer. Among them, bubbles with a diameter of 400-500 micrometers account for 85% of the total volume of bubbles in the gas-liquid mixing system.

[0099] Example 2

[0100] This embodiment is based on Embodiment 1, and the similarities will not be repeated. Only the differences will be explained below:

[0101] The blister structure adopts Figure 4 The bubble cap structure shown in the figure has an annular channel 73 outlet end 75 that provides micro-release pores by providing a porous medium with an equivalent diameter of 0.1 mm.

[0102] Through testing, the total gas content in the gas-liquid mixing system in the reaction chamber of this embodiment is 45%. The size distribution of bubbles in the gas-liquid mixing system in the reaction chamber is detected by a particle size analyzer, wherein bubbles with a diameter of 450-600 micrometers account for 80% of the total volume of bubbles in the gas-liquid mixing system.

[0103] Comparative Example 1

[0104] This comparative example is based on Example 1, and the similarities will not be repeated. Only the differences will be explained below:

[0105] In this comparative example, the gas-liquid bubbling device in the gas-liquid bubbling reaction apparatus is different from that in Example 1. Compared with the gas-liquid bubbling device used in Example 1, there is no bubble cap structure 7 in the inner cavity of the second expansion section.

[0106] The gas holdup in the gas-liquid mixture within the reaction chamber of this comparative example was found to be 30%. The size distribution of bubbles in the gas-liquid mixture was measured using a particle size analyzer. Bubbles with a diameter of 0.5-1 mm accounted for 30% of the total bubble volume, while bubbles with a diameter of 1-5 mm accounted for 50%. This indicates poor bubble size uniformity and a wide size distribution, clearly containing a large number of millimeter-sized bubbles, which reduces the gas-liquid interface area and thus affects mass transfer. Compared to Examples 1 and 2, the gas holdup was significantly lower because larger bubbles rise faster, smaller bubbles have a longer residence time, the number of small bubbles is less than in Examples 1 and 2, and the bubble size uniformity is poor, resulting in a lower gas holdup.

[0107] The experimental results above show that the gas-liquid bubbling generator with the composite structure of the present invention not only helps to reduce the bubble size and obtain micron-sized bubbles, but also has high size uniformity of micron-sized bubbles, which is beneficial to prolonging the contact time between the gas and liquid phases in the gas-liquid two-phase system and increasing the residence time of the gas phase, thereby enhancing mass transfer and reaction. Applying the gas-liquid bubbling generator of the present invention to the gas-liquid bubbling reaction device helps to solve the problems of poor bubble size uniformity, low mass transfer efficiency, and high energy consumption generated by the current gas-liquid bubbling reaction device.

[0108] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A composite structure gas-liquid bubbling generator, characterized in that, It includes a first Venturi structure and a second Venturi structure; the first Venturi structure includes a liquid phase inlet for introducing liquid phase material, a gas phase inlet for introducing gas phase material, and a first gas-liquid mixture outlet for releasing a first gas-liquid mixture flow. The first Venturi structure is used to cause the liquid phase material to squeeze and shear the gas phase material entrained by the gas phase inlet to obtain the first gas-liquid mixture flow containing microbubbles. The second Venturi structure is connected to the first Venturi structure and is used to further compress and shear the microbubbles in the first gas-liquid mixture to obtain the second gas-liquid mixture. The second Venturi structure includes a bubble cap structure, a hollow second contraction section, and a hollow second expansion section. The inner diameter of the second contraction section gradually decreases from its inlet to its outlet. The inlet of the second contraction section is interconnected with the first gas-liquid mixture outlet via multiple connecting holes. The second expansion section is fitted around the second contraction section, and the second expansion section has an overall expanded diameter structure. A second gas-liquid mixture outlet for releasing the second gas-liquid mixture is provided at the end with the larger inner diameter of the second expansion section. The bubble cap structure is located within the cavity of the second expansion section. The bubble cap structure includes a bubble cap shell, within which a drainage channel, a buffer space, and an annular channel surrounding the drainage channel are formed. The inlet of the drainage channel is connected to the outlet of the second contraction section, and the outlet of the drainage channel is connected to the inlet of the buffer space. The inlet of the annular channel is connected to the outlet of the buffer space, and the outlet of the annular channel is provided with multiple micro-release holes, which are connected to the cavity of the second expansion section. The volume of the buffer space is larger than the volume of the drainage channel and the annular channel, respectively, and the volume of the buffer space is 2-6 times the volume of the drainage channel or the annular channel; the outlet end of the annular channel is located at or near the bottom of the annular channel; the inner diameter of the buffer space gradually decreases from the inlet to the outlet of the drainage channel; the outlet and inlet of the buffer space are located on the same side as the outlet of the drainage channel.

2. The gas-liquid bubbling generator according to claim 1, characterized in that, The inner diameter of the drainage channel is less than or equal to the inner diameter of the outlet end of the second contraction section.

3. The gas-liquid bubbling generator according to claim 2, characterized in that, The micro-release pores can be provided by providing a porous medium at the outlet end of the annular channel; or the micro-release pores can be directly formed on the blister housing at a position corresponding to the outlet end of the annular channel.

4. The gas-liquid bubbling generator according to claim 3, characterized in that, The equivalent diameter of the micro-release pore is less than 1000 μm.

5. The gas-liquid bubbling generator according to claim 2, characterized in that, The connecting holes are provided by providing a perforated plate at the junction of the inlet end of the second contraction section and the outlet of the first gas-liquid mixture; Alternatively, the connecting hole can be directly opened on the end face of the second contraction section corresponding to the inlet end of the second contraction section; Alternatively, the first Venturi structure includes a hollow first contraction section, a gas-liquid mixing section, and a first expansion section, with the connecting hole directly formed on the end face of the first expansion section corresponding to the first gas-liquid mixture outlet; wherein, the first contraction section has a liquid phase inlet and a liquid phase outlet, and the inner diameter of the first contraction section gradually decreases from the liquid phase inlet to the liquid phase outlet; the first expansion section has a gas-liquid flow inlet and a first gas-liquid mixture outlet, and the inner diameter of the second expansion section gradually increases from the gas-liquid flow inlet to the first gas-liquid mixture outlet; the gas-liquid mixing section has a liquid inlet and a gas-liquid flow outlet at both ends, the liquid inlet communicating with the liquid phase outlet of the first contraction section, the gas-liquid flow outlet communicating with the gas-liquid flow inlet of the first expansion section, and the gas phase inlet located on the side wall of the gas-liquid mixing section; a gas phase inlet pipe is connected to the gas phase inlet.

6. The gas-liquid bubbling generator according to claim 5, characterized in that, The equivalent diameter of the connecting hole is 2~5 mm.

7. The gas-liquid bubbling generator according to claim 1, characterized in that, The inner diameter of the annular channel is uniform, or the inner diameter of the annular channel generally decreases from the entrance end to the bottom of the annular channel. And / or, the buffer space is generally conical, or the buffer space is generally trapezoidal.

8. The gas-liquid bubbling generator according to any one of claims 1-7, characterized in that, The second contraction section and the second expansion section are arranged coaxially.

9. The gas-liquid bubbling generator according to claim 8, characterized in that, On a cross section formed along the central axis of the second Venturi structure, the first included angle formed between the outlines of the sidewalls of the second contraction section is 15 to 45°; on a cross section formed along the central axis of the second Venturi structure, the second included angle formed between the outlines of the sidewalls of the second contraction section and the sidewalls of the second expansion section is 15 to 45°.

10. The gas-liquid bubbling generator according to claim 9, characterized in that, The first included angle is 20~30°, and the second included angle is 20~30°.

11. The gas-liquid bubbling generator according to claim 9, characterized in that, The first included angle and the second included angle are equal.

12. The gas-liquid bubbling generator according to any one of claims 1-4 and 7, characterized in that, The first Venturi structure includes a hollow first contraction section, a gas-liquid mixing section, and a first expansion section; The first contraction section is provided with a liquid phase inlet and a liquid phase outlet, and the inner diameter of the first contraction section gradually decreases from the liquid phase inlet to the liquid phase outlet. The first expansion section is provided with a gas-liquid inlet and a first gas-liquid mixture outlet. From the gas-liquid inlet to the first gas-liquid mixture outlet, the inner diameter of the second expansion section gradually increases. The gas-liquid mixing section has a liquid inlet and a gas-liquid outlet at each end. The liquid inlet is connected to the liquid phase outlet of the first contraction section, and the gas-liquid outlet is connected to the gas-liquid inlet of the first expansion section. The gas phase inlet is located on the side wall of the gas-liquid mixing section. A gas phase inlet pipe is connected to the gas phase inlet.

13. The gas-liquid bubbling generator according to claim 12, characterized in that, The ratio of the cross-sectional area of ​​the liquid inlet of the first contraction section to the liquid inlet of the gas-liquid mixing section is 8:1 to 2:1; the ratio of the cross-sectional area of ​​the end face of the first expansion section with the first gas-liquid mixing outlet to the gas-liquid mixing section outlet is 6:1 to 2:

1. And / or, the ratio of the inner diameter to the length of the gas phase inlet pipe is 0.01 to 0.

1.

14. The gas-liquid bubbling generator according to claim 13, characterized in that, The ratio of the cross-sectional area of ​​the liquid phase inlet of the first contraction section to the liquid inlet of the gas-liquid mixing section is 6:1 to 3:1; The ratio of the cross-sectional area of ​​the end face of the first expansion section where the first gas-liquid mixture outlet is located to the cross-sectional area of ​​the gas-liquid mixture outlet of the gas-liquid mixing section is 3.0:1 to 1.5:

1. And / or, the ratio of the inner diameter to the length of the gas phase inlet pipe is 0.01 to 0.

05.

15. The gas-liquid bubbling generator according to claim 12, characterized in that, In the first Venturi structure, the volume of the first contraction segment is greater than the volume of the first expansion segment; The volume of the second expansion section is greater than the volume of the first contraction section, and the volume of the second contraction section is less than the volume of the first contraction section.

16. The gas-liquid bubbling generator according to claim 12, characterized in that, The first contraction section, the gas-liquid mixing section, the first expansion section, the second contraction section, the bubble structure, and the second expansion section are arranged coaxially.

17. A gas-liquid bubbling reaction apparatus, characterized in that, The tower body includes a reaction chamber and a gas chamber inside its interior, and a gas inlet and a liquid inlet are provided on the tower body. The gas chamber is equipped with a gas-liquid bubbling device according to any one of claims 1-16; The gas phase inlet of the gas-liquid bubbling generator is connected to the gas phase feed port, the liquid phase inlet of the gas-liquid bubbling generator is connected to the liquid phase feed port, and the second gas-liquid mixed outlet of the gas-liquid bubbling generator is connected to the reaction chamber.

18. The gas-liquid bubbling reaction apparatus according to claim 17, characterized in that, A gas-liquid distribution plate is provided between the gas chamber and the reaction chamber. The gas-liquid distribution plate has distribution holes for connecting the gas chamber and the reaction chamber. The second gas-liquid mixing outlet of the gas-liquid bubbling device corresponds to the distribution holes of the gas-liquid distribution plate and is connected to each other.

19. The gas-liquid bubbling reaction apparatus according to claim 18, characterized in that, The number of gas-liquid bubbling devices is the same as the number of distribution holes in the gas-liquid distribution plate.

20. The gas-liquid bubbling reaction apparatus according to claim 18, characterized in that, The porosity of the distribution holes on the gas-liquid distribution plate is 0.3~0.7%.

21. The gas-liquid bubbling reaction apparatus according to claim 20, characterized in that, The porosity of the distribution holes on the gas-liquid distribution plate is 0.3%~0.5%.

22. An application characterized in that, The gas-liquid bubbling generating device according to any one of claims 1-16 or the gas-liquid bubbling reaction device according to any one of claims 17-21 is applied to a gas-liquid phase reaction system or a gas-liquid phase bubbling mass transfer.

23. The application according to claim 22, characterized in that, The apparent gas velocity inside the gas phase inlet of the gas-liquid bubbling reactor is greater than 0.01 m / s, the liquid phase material flow velocity inside the liquid phase inlet of the gas-liquid bubbling reactor is greater than 0.1 m / s, and the Reynolds number Re in the annular channel of the bubble cap structure is not less than 5000.

24. The application according to claim 22, characterized in that, The ratio of the liquid phase volumetric flow rate at the liquid inlet to the gas phase volumetric flow rate at the gas phase inlet of the gas-liquid bubbling reaction device is 1 to 100.

25. The application according to claim 24, characterized in that, The ratio of the liquid phase volumetric flow rate at the liquid inlet to the gas phase volumetric flow rate at the gas phase inlet of the gas-liquid bubbling reactor is 20 to 70.

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