Microbubble generation in a reaction system, sorting device and system using the same

Abstract

The application discloses a micro-bubble generating and sorting device in a reaction system, a system applying the device and can be applied to a gas-liquid or gas-liquid-solid catalytic reaction system. The device comprises a gas dissolving tank which receives a gas phase from a gas supply unit and a liquid phase from a liquid supply unit and carries out saturated gas dissolving; a micro-bubble generator which is a venturi structure and generates micro-bubbles after receiving the saturated gas dissolving liquid phase and carrying out air supplement; and a micro-bubble sorting tank which is provided with a gas-liquid mixture inlet from the micro-bubble generator on a side wall, the inlet extends to the central part of the tank body and is provided with a first releaser, and the opening of the first releaser faces downward. The liquid phase in the tank body is always in a downward flowing state and flows out from the bottom. Through the flow rate control of the liquid phase, the first micro-bubbles in the micro-bubbles flow downward along with the liquid phase in the bubble accompanying area, and the larger size diameter bubbles in the micro-bubbles rise to the gas releasing space under the action of buoyancy. The first micro-bubbles with a diameter less than 50 mu m can be sorted out through the setting of the micro-bubble sorting tank and the flow rate control of the liquid phase, and the gas-liquid mass transfer in the reaction system is promoted.

Description

Technical Field

[0001] This invention relates to the field of petrochemical technology, and in particular to a microbubble generation and sorting device for gas-liquid or gas-liquid-solid catalytic reaction systems, and a system using the device. Background Technology

[0002] In modern petrochemicals, gas-liquid and gas-liquid-solid catalytic reaction processes are common. The most frequently used fixed-bed reactor types are trickle beds and bubble beds, especially upward-flowing bubble beds, where the pressure drop remains consistently low. However, in the catalyst bed, the continuous liquid-phase gas flows in a bubbling manner, resulting in uneven gas-phase flow and affecting gas-liquid mass transfer. Maintaining a micro- or nano-bubble level in the gas phase would help overcome the shortcomings of upward-flowing bed reactors and highlight their advantages.

[0003] Micro- and nanobubbles are a highly specialized form of gas-liquid mixture. Microbubbles of micro- and nanoscale are present in the liquid phase, creating an emulsion-like state that can persist for a certain period. The bubbles rise within the liquid phase and collapse at the interface, clarifying the liquid phase. However, the liquid phase becomes supersaturated with a significant amount of dissolved gas, and a certain amount of nanobubbles still remain. These bubbles of varying sizes are commonly found at liquid and solid-liquid interfaces. Based on their diameter, they can be categorized as macrobubbles, micron-bubbles, micro- and nanobubbles, with microbubbles having a diameter less than 50 μm being classified as micro- and nanobubbles, which possess extremely wide-ranging applications.

[0004] Micro- and nano-bubbles can achieve a supersaturated state of gas solubility in the liquid phase, realizing gas-liquid mass transfer and generating high mass transfer efficiency. Since conventional gas distribution devices have openings at the millimeter level, it is currently difficult for all gas distribution devices to generate highly concentrated micro- and nano-bubbles. For example, Chinese patent application CN104874315A discloses a microbubble generator for enhanced hydrogenation processes, mainly composed of a main tube, a Venturi tube, an inlet pipe, and an ultrasonic generator. The Venturi tube and the main tube are coaxially arranged and welded to the inner wall of the main tube. An independent annular inlet space is formed between the outer wall of the Venturi tube and the inner wall of the main tube. The inlet pipe is welded to the outer wall of the main tube and connected to the annular inlet space. The Venturi tube is made of a microporous material. The inlet pipe, the annular inlet space, and the micropores of the Venturi tube together constitute a gas channel. The inner wall of the Venturi tube and the inner wall of the main tube together constitute a gas-liquid channel. The ultrasonic generator is installed on the outer wall of the main tube and located downstream of the Venturi tube.

[0005] Therefore, there is an urgent need for a microbubble generation and sorting device that can be applied to gas-liquid or gas-liquid-solid catalytic reaction systems, so as to separate the required first-stage microbubbles with a diameter of less than 50 μm from the larger-sized bubbles, thereby better promoting gas-liquid mass transfer in the reaction system.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a microbubble generation and sorting device for a reaction system and a system using the device. By setting up a microbubble sorting tank and controlling the liquid flow rate, the required first-stage microbubbles with a diameter of less than 50 μm can be sorted from bubbles with a larger diameter, thereby better promoting gas-liquid mass transfer in the reaction system.

[0008] Another objective of this invention is to obtain secondary micron bubbles (50μm-500μm micron bubbles) by recovering and sorting the gas phase and performing dissolved gas treatment. These bubbles are then introduced into the reaction system at intervals or in appropriate amounts. This not only effectively utilizes the recovered gas but also increases the turbulent kinetic energy of the liquid phase, rapidly removes the heat of reaction, and reduces catalyst coking.

[0009] To achieve the above objectives, according to a first aspect of the present invention, the present invention provides a microbubble generation and sorting device for a reaction system, applicable to gas-liquid or gas-liquid-solid catalytic reaction systems, comprising: a gas-dissolving tank that receives gas phase from a gas supply unit and liquid phase from a liquid supply unit and performs saturated gas dissolution; a microbubble generator having a Venturi structure and generating microbubbles after receiving saturated dissolved gas liquid phase and replenishing gas; and a microbubble sorting tank having a gas-liquid mixture inlet from the microbubble generator on its side wall, the inlet extending to the center of the tank and having a first release device with its opening facing downwards; the liquid phase inside the tank is always in a downward flowing state and flows out from the bottom, and by controlling the flow rate of the liquid phase, the first-stage micron-sized bubbles in the microbubbles flow downwards with the liquid phase in the bubble-following zone, while larger-diameter bubbles in the microbubbles rise to the gas release space under the action of buoyancy.

[0010] Furthermore, in the above technical solution, the microbubble sorting tank can be a tank body composed of a combination of columnar and conical sections, with the gas-liquid mixture inlet located in the middle of the columnar section and the microbubble sorting tank outlet located at the bottom of the conical section.

[0011] Furthermore, in the above technical solution, the bubble-following zone is the area located between the opening of the first releaser and the bottom of the columnar section, and the height of the bubble-following zone can be determined according to the release speed of the first releaser.

[0012] Furthermore, in the above technical solution, the flow rate of the liquid phase in the microbubble separation tank is kept constant. The liquid flow rate in the tank can be controlled by the first liquid level display control unit and the flow rate display control unit, and the gas pressure in the tank can be maintained by the pressure display control unit. The first liquid level display control unit is installed below the normal operating liquid level of the microbubble separation tank, and the constant downward flow rate of the liquid phase is obtained by maintaining the stability of the liquid level.

[0013] Furthermore, in the above technical solution, the flow rate of the liquid phase inside the microbubble sorting tank is kept constant and can also be controlled by a pressure display control unit and a dissolved gas pump to maintain the stability of the gas pressure and liquid level inside the tank. The pressure display control unit is connected to the gas release space inside the tank, and the dissolved gas pump receives the liquid phase from the tank and the gas phase from the gas release space, maintaining the stability of the liquid level inside the tank while dissolving the gas, thereby obtaining a constant downward flow rate of the liquid phase inside the tank.

[0014] Furthermore, in the above technical solution, the microbubble generator can be replenished with gas through a gas buffer tank. The gas replenishment port is located at the top of the narrowed section of the Venturi structure, and the gas replenishment flow direction is perpendicular to the flow direction of the gas-liquid mixture.

[0015] Furthermore, in the above technical solution, the dissolved gas tank can be controlled by a second liquid level display and control unit.

[0016] Furthermore, in the above technical solution, the liquid phase inlet in the dissolved gas tank is located at the top, and a liquid distributor can be installed at the liquid phase inlet.

[0017] According to a second aspect of the present invention, the present invention provides a reaction system using any of the foregoing devices, comprising: an upflow reactor having, from bottom to top, a clear liquid circulation zone, a gas-liquid diffusion zone, and a packed bed; the gas-liquid diffusion zone receiving a gas-liquid mixture containing primary micron bubbles from a microbubble sorting tank and diffusing it upwards; the upwardly diffused gas-liquid mixture continuing to rise into the packed bed and undergoing an enhanced mass transfer reaction; the liquid phase after primary micron bubble diffusion forming a clear liquid and accumulating in the clear liquid circulation zone at the bottom of the upflow reactor.

[0018] Furthermore, in the above technical solution, a second release device with an upward-facing opening can be connected to the gas-liquid diffusion zone via a pipeline. This second release device is located at the axial position of the upflow reactor.

[0019] Furthermore, in the above technical solution, a third release device can be connected to the gas-liquid diffusion zone via a pipeline. This third release device is connected to the outlet of the dissolved gas pump. The dissolved gas pump receives the liquid phase from the microbubble sorting tank and the gas phase from the gas release space, dissolves the gas, and then pumps secondary micron bubbles into the gas-liquid diffusion zone.

[0020] Furthermore, in the above technical solution, the third releaser can be set at a position offset from the axis of the upflow reactor and higher than the second releaser.

[0021] Furthermore, in the above technical solution, the clear liquid in the clear liquid circulation zone can be pumped to the liquid supply unit by the clear liquid circulation pump.

[0022] Furthermore, in the above technical solution, the reaction system may also include a liquid supply unit, which includes a liquid phase raw material tank, a feed metering pump and a fixed bed filter connected in sequence, for providing liquid phase raw materials to the dissolved gas tank.

[0023] Furthermore, in the above technical solution, the reaction system may also include a gas supply unit, which includes a gas cylinder, a gas compressor and a gas flow meter connected in sequence, and supplies gas to the dissolved gas tank and replenishes gas to the microbubble generator, respectively.

[0024] Furthermore, in the above technical solution, the upflow reactor can be a hydrorefining reactor.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1) Based on the characteristics of micro- and nano-sized bubbles, the inventors discovered that these bubbles can achieve a supersaturated state of gas solubility in the liquid phase, realizing gas-liquid mass transfer and generating high mass transfer efficiency. Further research revealed that smaller bubbles exhibit better buoyancy in the liquid phase. Since the density of gas is less than that of liquid, when bubbles appear in the liquid phase, they rise slowly to the surface due to buoyancy. Larger bubbles experience stronger buoyancy and rise faster; as bubble size decreases, the rising speed slows significantly. Based on this, the present invention sorts the bubbles generated by the bubble generator to obtain the required first-order micron-sized bubbles with a diameter less than 50 μm.

[0027] 2) This invention uses a microbubble sorting tank for sorting. The pre-reserved bubble-following zone inside the tank ensures that larger diameter bubbles have space to turn around and run, that is, they first go down and then go up by buoyancy to enter the gas release space. Meanwhile, the required first-stage microbubbles with a diameter of less than 50μm can rely on their good accompanying performance to run down with the liquid phase, thereby achieving the purpose of bubble sorting.

[0028] 3) The present invention can keep the flow rate of the liquid phase in the microbubble sorting tank constant through the coordinated action of the first liquid level display control unit, the flow rate display control unit and the pressure display control unit, thereby enabling effective sorting of bubbles and obtaining enriched first-level micron bubbles;

[0029] 4) The present invention can also control the liquid level in the microbubble sorting tank by means of a dissolved gas pump, thereby replacing the liquid level display control unit and flow display control unit used to control the constant flow rate of the liquid phase in the tank. It can also recover and utilize the gas escaping from the tank and further generate secondary microbubbles with a size between 50μm and 500μm. That is, the secondary microbubbles of the present invention are generated by the dissolved gas pump. The secondary microbubbles can also be used in the reaction system of subsequent applications to improve the turbulent kinetic energy of the liquid phase, quickly remove the heat of reaction, and reduce catalyst coking.

[0030] 5) When the microbubble generation and sorting device of the present invention is applied in a hydrogenation reactor, the first-stage microbubbles can effectively enhance the gas-liquid mass transfer reaction in the packed bed, while the second-stage microbubbles can increase the turbulent kinetic energy of the liquid phase, quickly remove the heat of reaction, and reduce catalyst coking.

[0031] 6) By staggering the second and third releasers, the present invention can minimize the interference between the released secondary micron bubbles and the released primary micron bubbles; and since the two types of micron bubbles released in the gas-liquid diffusion zone are both small in size and the difference between their sizes is not large, they are not easy to generate a coalescence effect in the gas-liquid diffusion zone, and can play their respective roles.

[0032] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the connection of a reaction system using the microbubble generation and sorting device of the present invention in the first embodiment.

[0034] Figure 2 This is a schematic diagram of the connection of a reaction system using the microbubble generation and sorting device of the present invention in a second embodiment.

[0035] Explanation of key figure labels:

[0036] 1-Liquid phase feed tank, 2-Gas compressor, 3-First-stage gas flow meter, 4-Second-stage gas flow meter, 5-Gas buffer tank, 6-Microbubble sorting tank, 7-Pressure display and control unit, 8-Pressure control valve, 9-Reactor outlet, 10-Feed metering pump, 11-Fixed bed filter, 12-Second liquid level display and control unit, 13-Second liquid level control valve, 14-Liquid distributor, 15-Dissolved gas tank, 16-Microbubble generator, 17-Gas release space, 18-Bubble travel zone, 19-Conical section, 20-First releaser, 21-First liquid level display and control unit, 22-Flow display and control unit, 23-Flow control valve, 24-Clear liquid circulation pump, 25-Second releaser, 26-Packed bed, 27-Gas-liquid two-phase diffusion zone, 28-Clear liquid circulation zone, 29-Upflow reactor, 30-Third releaser, 31-Dissolved gas pump. Detailed Implementation

[0037] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0038] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0039] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0040] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0041] The inventors discovered that microbubbles exhibit high gas-liquid mass transfer efficiency, particularly microbubbles with a diameter less than 50 μm (referred to in this invention as first-order microbubbles, which also include nanobubbles with even smaller diameters). The volume and diameter of the gas in a liquid together determine the specific surface area of ​​the gas-liquid mixture, which in turn determines the gas mass transfer efficiency. Surface tension theory at the gas-liquid interface reveals that as the bubble diameter decreases, the influence of surface tension becomes more pronounced. First-order microbubbles or nanobubbles, with their smaller diameters compared to ordinary bubbles, are more significantly affected by surface tension, leading to their contraction and a gradual increase in internal pressure. When the contraction of micro / nanobubbles reaches a certain limit, the internal gas pressure tends towards infinity. This self-pressurization effect causes the micro / nanobubbles to dissolve in water or burst and disappear at the water surface. Through this process, the gas solubility in the liquid phase can reach a supersaturated state, achieving gas-liquid mass transfer while simultaneously generating high mass transfer efficiency. Smaller bubbles exhibit better buoyancy in the liquid phase. Since the density of gas is less than that of liquid, when a bubble appears in the liquid phase, it rises slowly until it reaches the surface due to buoyancy. Larger bubbles experience stronger buoyancy and rise faster. Calculations using Stokes' law show that as bubble size decreases, the rising speed slows significantly, and the bubble can even remain in the liquid phase for several minutes (i.e., exhibiting stronger buoyancy). The relationship between bubble rising speed and bubble diameter shows that a 1mm diameter bubble rises at 100mm / s in water, while a 10μm diameter bubble rises at only 0.05mm / s, the latter being 1 / 2000th the former. The longer the bubble remains in the liquid, the more thorough the contact between the bubble and the liquid.

[0042] This invention utilizes this principle to sort the generated bubbles. Large bubbles have relatively gentle movement paths, easily escaping the constraints of the low-speed liquid phase and are less affected by liquid flow. Under a certain liquid velocity, large bubbles can preferentially rise to the interface and collapse. In contrast, microbubbles rise slowly and are less prone to coalescing. Their upward path is tortuous, and they easily move downwards with the liquid phase, demonstrating their accompanying properties. In this process, the magnitude of the liquid-liquid flow velocity is the key factor in separating bubble sizes. This invention, by controlling a constant downward flow velocity of the liquid phase in the microbubble sorting tank, allows larger bubbles to rise, while first-order microbubbles with a diameter less than 50 μm move downwards with the liquid phase, achieving bubble sorting. The sorted first-order microbubbles (including nano-sized bubbles) with a diameter less than 50 μm can then be applied to gas-liquid or gas-liquid-solid reaction systems, enhancing the gas-liquid mass transfer effect of the reaction system.

[0043] The microbubble generation and sorting device of the present invention can be applied not only to gas-liquid reactions, but also to gas-liquid-solid catalytic reaction systems. For example, when applied to a hydrorefining reaction system, the liquid phase is feedstock oil, and the gas phase is hydrogen.

[0044] Example 1

[0045] like Figure 1 As shown, this embodiment provides a specific implementation of a microbubble generation and sorting device, which can be applied to gas-liquid or gas-liquid-solid catalytic reaction systems, and includes at least a dissolved gas tank 15, a microbubble generator 16, and a microbubble sorting tank 6. The dissolved gas tank 15 receives the gas phase from the gas supply unit and the liquid phase from the liquid supply unit and performs saturated gas dissolution. The microbubble generator 16 has a Venturi structure and generates microbubbles after receiving the saturated dissolved gas liquid phase and replenishing it with gas. The side wall of the microbubble sorting tank 6 is provided with a gas-liquid mixture inlet from the microbubble generator 16, extending to the center of the tank and equipped with a first release device 20, the opening of which faces downwards. The liquid phase inside the tank is always in a downward flowing state and flows out from the bottom. By controlling the flow rate of the liquid phase, the first-stage micron-sized bubbles (i.e., those with a diameter less than 50 μm) in the microbubble flow downwards with the liquid phase in the bubble-following zone, while larger-diameter bubbles in the microbubble rise to the gas release space under the action of buoyancy.

[0046] The inventors discovered that for a vertically positioned microbubble sorting tank 6, a high downward liquid flow velocity results in more retained bubbles and a wider bubble size distribution; conversely, a slower liquid flow velocity results in fewer retained bubbles and a narrower bubble size distribution. Further research revealed the relationship between bubble size and its upward velocity in the corresponding liquid phase. By setting and adjusting the structural parameters and internal liquid phase operating parameters of the microbubble sorting tank 6, separation of microbubbles with a diameter of approximately 50 μm or larger can be achieved within the tank. This invention, with a fixed tank structure and dimensions, can separate first-stage microbubbles with a diameter less than 50 μm by controlling the downward flow velocity of the liquid phase within the tank.

[0047] Specifically, further as Figure 1 As shown, the dissolved gas tank 15 includes a liquid inlet and a gas inlet. The liquid inlet is located at the top of the dissolved gas tank 15, and a liquid distributor 14 is installed at the liquid inlet to improve the liquid flowability and gas dissolution capacity. The second liquid level control valve 13 on the liquid inlet pipeline is linked with the second liquid level display and control unit 12 of the dissolved gas tank 15 to form a coordinated control of the operating liquid level of the dissolved gas tank 15. By controlling the pressure inside the dissolved gas tank 15, the gas and liquid phases are saturated and dissolved within the dissolved gas tank 15.

[0048] Further as Figure 1As shown, the venturi tube of the microbubble generator 16 has a liquid inlet (for receiving the gas-liquid two-phase mixture after saturation of dissolved gas), a gas supply port, and a gas-liquid two-phase outlet. The microbubble generator 16 receives gas supply through a gas buffer tank 5. The gas supply port is located at the top of the narrowed section of the venturi structure, and the gas supply flow direction is perpendicular to the flow direction of the gas-liquid mixture. Although most of the bubbles generated by the microbubble generator 16 are at the micrometer level, they inevitably exhibit a wide distribution and range of bubble sizes, primarily between 10 and 1000 μm.

[0049] Further as Figure 1 As shown, bubbles between 10-1000 μm generated by the microbubble generator 16 enter the microbubble sorting tank 6 of this invention for sorting. In this embodiment, the microbubble sorting tank 6 is a combination of a cylindrical section and a conical section. The gas-liquid mixture inlet is located in the middle of the cylindrical section, and the outlet of the microbubble sorting tank 6 is located at the bottom of the conical section. The conical section can neck to accelerate the gas-liquid two-phase flow, improving its fluidity. The bubble-following zone 18 of the microbubble sorting tank 6 is the area between the opening of the first releaser 20 and the bottom of the cylindrical section. The height of the bubble-following zone 18 can be determined according to the release speed of the first releaser 20. Since the bubbles initially move downwards after being released into the tank, while larger bubbles rise under buoyancy, space is needed for larger bubbles to make a turning motion. The bubble size and the rising speed are linearly related; the larger the bubble, the faster the rising speed. Because large bubbles move upward quickly, they continuously converge during their ascent, generating even larger bubbles. The movement path of these large bubbles is relatively gentle, making it easy for them to break free from the constraints of the slowly descending liquid phase. They then escape and collapse at the interface of the gas release space 17. While the primary microbubbles required by this invention also tend to rise under buoyancy, their ascent speed is slow, and they do not coalesce. The upward path of these microbubbles is tortuous, making them prone to descending with the liquid phase. Therefore, this invention, by controlling the liquid flow rate within the tank and stabilizing it at a calculable required flow rate, can separate the generated primary microbubbles (i.e., those with a diameter less than 50 μm) from the microbubbles with a particle size range of 10-1000 μm.

[0050] Further as Figure 1As shown, the liquid flow rate in this embodiment can be controlled in the following way: the liquid flow rate in the microbubble sorting tank 6 is kept constant. The liquid flow rate in the tank is controlled by the first liquid level display control unit 21 and the flow rate display control unit 22, and the gas pressure in the tank is maintained by the pressure display control unit 7. The first liquid level display control unit 21 is installed below the normal operating liquid level of the microbubble sorting tank, and a constant downward flow rate of the liquid phase is obtained by maintaining a stable liquid level. Specifically, when the operating conditions remain unchanged, as the amount of bubbles escaping in the microbubble sorting tank 6 increases, the pressure in the gas release space 17 increases, and the liquid level in the microbubble sorting tank 6 decreases. This triggers the pressure display control unit 7 and the first liquid level display control unit 21, and the signal is transmitted to the flow rate display control unit 22. The flow control valve 23 is adjusted to maintain the stability of the pressure and liquid level in the tank.

[0051] In this embodiment, the generation of microbubbles and the separation of primary micron-sized bubbles from larger-diameter bubbles are achieved through the dissolved gas tank 15, the microbubble generator 16, and the microbubble sorting tank 6. This provides the subsequent reaction system with bubbles of less than 50 μm in diameter that are more conducive to gas-liquid mass transfer. The coordinated action of the first liquid level display control unit 21, the flow rate display control unit 22, and the pressure display control unit 7 keeps the flow rate of the liquid phase in the microbubble sorting tank constant, thereby enabling effective bubble sorting.

[0052] Example 2

[0053] like Figure 2 As shown, this embodiment provides another specific implementation of a microbubble generation and sorting device, which can be applied to gas-liquid or gas-liquid-solid catalytic reaction systems. Similar to the embodiment, it also includes at least a dissolved gas tank 15, a microbubble generator 16, and a microbubble sorting tank 6. The corresponding structures and connection methods of the dissolved gas tank 15, microbubble generator 16, and microbubble sorting tank 6 are basically the same as in Embodiment 1. The difference from Embodiment 1 is that this embodiment uses a different implementation method to control the liquid phase flow rate: that is, the flow rate of the liquid phase in the microbubble sorting tank 6 is kept constant, controlled by a pressure display control unit 7 and a dissolved gas pump 31, to maintain stable gas pressure and liquid level inside the tank. The pressure display control unit 7 is connected to the gas release space inside the tank, and the dissolved gas pump 31 receives the liquid phase from inside the tank and the gas phase from the gas release space, maintaining a stable liquid level inside the tank while dissolving the gas, thereby obtaining a constant downward flow rate of the liquid phase inside the tank.

[0054] In this embodiment, a liquid phase outlet is provided at the side wall opening of the microbubble sorting tank 6, and a gas phase outlet is provided at the top. The gas and liquid phases dissolve in the dissolved gas pump 31. The dissolved gas pump 31 can control the liquid level in the microbubble sorting tank 6, thereby replacing the liquid level display control unit 21 and flow display control unit 22 used in Embodiment 1. It can also recover and reuse the escaped gas to further generate bubbles. The size of the further generated bubbles can reach 50μm-500μm, that is, the secondary microbubbles of this invention can be generated by the dissolved gas pump 31. The secondary microbubbles can also be used in the reaction system of subsequent applications to improve the turbulent kinetic energy of the liquid phase, quickly remove the heat of reaction, and reduce catalyst coking.

[0055] Example 3

[0056] like Figure 1 As shown, this embodiment is a system embodiment, which uses the microbubble generation and sorting device of Embodiment 1. The hydrorefining reactor is used as an example for illustration (the liquid phase is raw oil and the gas phase is hydrogen). The parts that are the same as the microbubble generation and sorting device in Embodiment 1 will not be described again here.

[0057] The system of this embodiment includes an upflow reactor 29, which has, from bottom to top, a clear liquid circulation zone 28, a gas-liquid diffusion zone 27, and a packed bed 26. The gas-liquid diffusion zone 27 receives a gas-liquid mixture containing primary micron-sized bubbles from the microbubble sorting tank 6 and diffuses it upwards. The upwardly diffused gas-liquid mixture continues to flow into the packed bed 26 and undergoes an enhanced mass transfer reaction. The liquid phase after primary micron-sized bubble diffusion forms a clear liquid and accumulates in the clear liquid circulation zone 28 at the bottom of the upflow reactor 29. Further, preferably but not limitingly, a second release device 25 with an upward-facing opening is connected to the gas-liquid diffusion zone 27 via a pipeline, and the second release device 25 is located at the axial position of the upflow reactor 29.

[0058] Furthermore, the clarified liquid in the clarified liquid circulation zone 28 can be pumped to the liquid supply unit for recycling via the clarified liquid circulation pump 24. The liquid supply unit may include a liquid phase feed tank 1, a feed metering pump 10, and a fixed bed filter 11 connected in sequence, for providing liquid phase feed to the dissolved gas tank. The fixed bed filter 11 can be used for feedstock oil pretreatment filtration, and may also be a cartridge filter or any device including but not limited to that capable of filtering hydrocarbon oils. The reaction system also includes a gas supply unit, which may include a gas cylinder (not shown in the figure), a gas compressor 2, and gas flow meters (including a primary gas flow meter 3 and a secondary gas flow meter 4) connected in sequence, for supplying gas to the dissolved gas tank 15 and replenishing gas to the microbubble generator 16, respectively.

[0059] Specifically, the hydrogen route (i.e., the gas supply unit) includes primary hydrogen supply and secondary hydrogen replenishment. Feedstock oil is fed from the liquid phase feed tank 1 through the feed metering pump 10 into the fixed bed filter 11 for treatment before entering the dissolved gas tank 15. The dissolved gas tank 15 includes a liquid phase inlet and a gas phase inlet. A liquid distributor 14 is installed at the liquid phase inlet to improve liquid flowability and hydrogen dissolution capacity. The second liquid level control valve 13 on the liquid phase pipeline (i.e., the liquid supply unit) is linked with the second liquid level display and control unit of the dissolved gas tank 15 to regulate the liquid level in the dissolved gas tank 15. The gas phase inlet of the dissolved gas tank 15 is connected to the primary gas flow meter 3 and the gas compressor 2 to form a primary hydrogen supply route and control the pressure inside the dissolved gas tank. After the gas and liquid phases are saturated with hydrogen in the dissolved gas tank 15, they enter the microbubble generator 16 for secondary hydrogen replenishment and generate micron bubbles (including some of the required primary micron bubbles). The microbubble generator 16 is equipped with a hydrogen-dissolving oil inlet, a secondary hydrogen replenishment port and a gas-liquid two-phase flow outlet. The secondary hydrogen replenishment route is that the hydrogen is compressed by the gas compressor 2, controlled by the secondary gas flow meter 4, buffered by the gas buffer tank 5 and then enters the secondary hydrogen replenishment port.

[0060] Furthermore, by adjusting the liquid flow rate in the microbubble sorting tank 6, the liquid level drop rate can be controlled, so that the liquid phase flow rate remains constant, thereby achieving the efficient enrichment and sorting process of bubbles of the required particle size (i.e., first-stage micron bubbles) (for specific control methods, please refer to Example 1).

[0061] Furthermore, the separated and enriched primary micron-sized bubbles are accelerated by the conical section 19 of the sorting tank and enter the gas-liquid two-phase diffusion zone 27 of the upflow reactor 29 through the bottom feed pipeline. Under the action of the secondary release device 25, the feed oil mixed with primary micron-sized bubbles diffuses upward and continues to rise to the packed bed 26 for enhanced mass transfer reaction. After the bubble diffusion is completed, the feed oil forms a clear liquid that accumulates in the clear liquid circulation zone 28 at the bottom of the upflow reactor 29. The clear liquid can be circulated back to the dissolved gas tank 15 by the clear liquid circulation pump 24 for re-dissolving hydrogen and replenishing hydrogen, which is more conducive to controlling the hydrogen-to-oil ratio. After the reaction is completed, the product is discharged through the top outlet 9.

[0062] Example 4

[0063] like Figure 2As shown, the microbubble generation and sorting device of Example 2 is applied. The hydrorefining reactor is still used as an example for explanation (the liquid phase is feedstock oil, and the gas phase is hydrogen). The parts identical to those in Example 2, as well as the gas supply unit and liquid supply unit identical to those in Example 3, will not be described again here. This example is a system implementation based on Example 2, that is, using a dissolved gas pump 31 and a pressure display control unit 7 to control the liquid phase flow rate in the microbubble sorting tank 6. This not only effectively controls the liquid phase flow rate in the microbubble sorting tank 6, but also provides secondary micron-sized bubbles (i.e., bubbles with a diameter range of 50μm-500μm) for the hydrorefining reaction system.

[0064] Specifically, a third release device 30 is connected to the gas-liquid diffusion zone 27 of the upflow reactor 29 via a pipeline. The third release device 30 is connected to the outlet of the dissolved gas pump 31. The dissolved gas pump receives the liquid phase from the microbubble sorting tank and the gas phase from the gas release space, dissolves the gas, and pumps secondary micron-sized bubbles into the gas-liquid diffusion zone 27. Preferably, but not limitingly, the third release device 30 can be located off-center from the axis of the upflow reactor 29 and higher than the second release device 25. This configuration minimizes interference between the released secondary microbubbles and the primary microbubbles released in the second releaser 25. It's important to note that the gas-liquid mixture in the dissolved gas pump 31 originates from the level control margin in the microbubble sorting tank 6. Therefore, the overall quantity of secondary microbubbles is relatively small, and their diameter ranges from 50μm to 500μm, slightly larger than that of the primary microbubbles. Those skilled in the art know that larger bubbles are more prone to coalescence in the liquid phase. However, in this embodiment, both types of microbubbles released in the gas-liquid diffusion zone 27 have relatively small diameters with little difference between them, thus preventing coalescence in the diffusion zone 27. Therefore, the two types of microbubbles can each play their respective roles: the primary microbubbles enhance gas-liquid mass transfer after entering the filling layer 26, while the secondary microbubbles increase the turbulent kinetic energy of the liquid phase, rapidly removing reaction heat and reducing catalyst coking.

[0065] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A microbubble generation and sorting device for a reaction system, characterized in that, Applied to gas-liquid or gas-liquid-solid catalytic reaction systems, including: A dissolved gas tank receives gas from a gas supply unit and liquid from a liquid supply unit and performs saturated gas dissolution. A microbubble generator, which has a venturi structure, generates microbubbles after receiving the liquid phase of the saturated dissolved gas and replenishing it with gas. The microbubble sorting tank has a gas-liquid mixture inlet from the microbubble generator on its side wall. The inlet extends to the center of the tank and is equipped with a first release device with its opening facing downwards. The liquid phase inside the tank is always flowing downwards and out from the bottom. By controlling the flow rate of the liquid phase, the first-stage microbubbles in the microbubbles flow downwards with the liquid phase in the bubble-following zone. The first-stage microbubbles refer to microbubbles with a diameter of less than 50 μm. Larger diameter bubbles in the microbubbles rise to the gas release space under the action of buoyancy. The microbubble sorting tank is a tank composed of a columnar section and a conical section. The gas-liquid mixture inlet is located in the middle of the columnar section, and the microbubble sorting tank outlet is located at the bottom of the conical section. The bubble-following zone is the area between the opening of the first release device and the bottom of the columnar section. The height of the bubble-following zone is determined according to the release rate of the first release device.

2. The microbubble generation and sorting device in the reaction system according to claim 1, characterized in that, The flow rate of the liquid phase inside the microbubble sorting tank is kept constant. The liquid flow rate inside the tank is controlled by a first liquid level display control unit and a flow rate display control unit, and the gas pressure inside the tank is maintained by a pressure display control unit. The first liquid level display control unit is installed below the normal operating liquid level of the microbubble sorting tank, and a constant downward flow rate of the liquid phase is obtained by maintaining a stable liquid level.

3. The microbubble generation and sorting device in the reaction system according to claim 1, characterized in that, The flow rate of the liquid phase inside the microbubble sorting tank is kept constant and controlled by a pressure display control unit and a dissolved gas pump to maintain stable gas pressure and liquid level inside the tank. The pressure display control unit is connected to the gas release space inside the tank. The dissolved gas pump receives the liquid phase from the tank and the gas phase from the gas release space, maintaining a stable liquid level inside the tank while dissolving the gas, thereby obtaining a constant downward flow rate of the liquid phase inside the tank.

4. The microbubble generation and sorting device in the reaction system according to claim 1, characterized in that, The microbubble generator is replenished with gas through a gas buffer tank. The gas replenishment port is located at the top of the narrowed section of the Venturi structure, and the gas replenishment flow direction is perpendicular to the flow direction of the gas-liquid mixture.

5. The microbubble generation and sorting device in the reaction system according to claim 1, characterized in that, The dissolved gas tank is controlled by a second liquid level display and control unit.

6. The microbubble generation and sorting device in the reaction system according to claim 1, characterized in that, The liquid phase inlet of the dissolved gas tank is located at the top, and a liquid distributor is installed at the liquid phase inlet.

7. A reaction system using the apparatus as described in any one of claims 1 to 6, characterized in that, include: An upflow reactor has, from bottom to top, a clear liquid circulation zone, a gas-liquid diffusion zone, and a packing bed. The gas-liquid diffusion zone receives a gas-liquid mixture containing primary micron-sized bubbles from a microbubble sorting tank and diffuses it upwards. The upward-diffused gas-liquid mixture continues to rise into the packed bed and undergoes enhanced mass transfer reaction; the liquid phase after the first-stage micron bubble diffusion forms a clear liquid and accumulates in the clear liquid circulation zone at the bottom of the upflow reactor.

8. The reaction system according to claim 7, characterized in that, A second release device with an upward-facing opening is connected to the gas-liquid diffusion zone via a pipeline. The second release device is located at the axial position of the upflow reactor.

9. The reaction system according to claim 8, characterized in that, When the constant flow rate of the liquid phase in the microbubble sorting tank is controlled by the pressure display control unit and the dissolved gas pump, a third release device is also connected to the gas-liquid diffusion zone through a pipeline. The third release device is connected to the outlet of the dissolved gas pump. The dissolved gas pump receives the liquid phase from the microbubble sorting tank and the gas phase from the gas release space, dissolves the gas, and then pumps secondary micron bubbles into the gas-liquid diffusion zone. The secondary micron bubbles refer to micron bubbles with a diameter of 50μm-500μm.

10. The reaction system according to claim 9, characterized in that, The third release device is positioned off-center from the axis of the upflow reactor and is higher than the second release device.

11. The reaction system according to claim 7, characterized in that, The clear liquid in the clear liquid circulation zone is pumped to the liquid supply unit by the clear liquid circulation pump.

12. The reaction system according to claim 7, characterized in that, The reaction system also includes a liquid supply unit, which comprises a liquid phase feed tank, a feed metering pump, and a fixed bed filter connected in sequence, for supplying liquid phase feed to the dissolved gas tank.

13. The reaction system according to claim 7, characterized in that, The reaction system also includes a gas supply unit, which comprises a gas cylinder, a gas compressor, and a gas flow meter connected in sequence, and supplies gas to the dissolved gas tank and replenishes gas to the microbubble generator, respectively.

14. The reaction system according to claim 7, characterized in that, The upflow reactor is a hydrorefining reactor.

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