Semiconductor industry wastewater treatment system and configuration method

Abstract

The application discloses a semiconductor industry wastewater treatment system and a configuration method, comprising an ultrafiltration device, a reverse osmosis device and a gas-liquid separation device between the two. The system uses a tangential inflow assembly to cooperate with a flow guide assembly in a cyclone area to force fluid rotation and descent, separates micro-bubbles in ultrafiltration water through centrifugal force; uses a gas sweeping assembly to release protective gas to replace precipitated gas and reduce dissolved oxygen; and uses a vortex prevention member with a closed top and a side wall opening in the liquid outlet assembly to physically block gas bubbles on the liquid surface from entering the downstream. The semiconductor industry wastewater treatment system effectively solves the problems of cavitation of high-pressure pumps, gas blockage and oxidation pollution of reverse osmosis membranes caused by micro-bubbles and high dissolved oxygen, significantly improves the system stability and prolongs the service life of the equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to a wastewater treatment system, in particular to a semiconductor industry wastewater treatment system and configuration method. BACKGROUND

[0002] With the rapid development of the semiconductor industry, the treatment and resource recycling of wastewater generated in the production process have become the focus of the industry. Semiconductor wastewater is complex, usually containing heavy metal wastewater such as copper / nickel, fluorine-containing wastewater, and grinding wastewater, etc. In order to achieve efficient recycling of water resources, the industry generally adopts a reduction and recycling process. In a typical semiconductor wastewater recycling treatment process, after pretreatment such as chemical precipitation, the wastewater usually enters a double-membrane deep treatment system, that is, an ultrafiltration device is used as a pretreatment unit to intercept colloids and suspended particles, and then a reverse osmosis device (RO) is connected in series for deep desalination and removal of dissolved substances, and the final product water can be used for cooling tower make-up water or as raw water for a pure water preparation system.

[0003] In the existing semiconductor wastewater treatment system, the ultrafiltration device and the reverse osmosis device are usually directly connected through an intermediate water tank and a conveying pipeline, or only a simple buffer container is provided. In order to maintain the filtration flux of the ultrafiltration membrane and prevent the membrane holes from being blocked, high-strength air scouring and backwashing operations must be performed on the ultrafiltration membrane assembly at regular intervals during process operation, for example, using compressed air to clean the membrane wire with a large flow rate. The effluent after ultrafiltration treatment is usually pressurized by a high-pressure pump and then directly sent to the downstream reverse osmosis system. In order to prevent the reverse osmosis membrane from being contaminated, the existing technical improvements usually focus on adding a security filter before the reverse osmosis device to intercept small particles, or adding a scale inhibitor to prevent inorganic salt scaling.

[0004] However, the inventors have found in actual engineering practice that the above-mentioned existing technology has significant defects in gas-liquid control and connection, which directly restricts the operation stability of the reverse osmosis system. First, due to the frequent high-strength air scouring of the ultrafiltration device, a large amount of micro-bubbles is easily entrained in the ultrafiltration effluent, and the dissolved gas in the water body is often in a supersaturated state. The existing intermediate water tank or pipeline lacks an efficient forced gas-liquid separation mechanism, so these bubbles are directly sucked into the high-pressure pump of the reverse osmosis system with the water flow, which easily causes pump body cavitation, severe vibration and noise, and seriously shortens the service life of the high-pressure pump. Second, when the water flow with bubbles and high concentration of dissolved oxygen enters the reverse osmosis membrane assembly, the micro-bubbles will accumulate on the membrane surface to form a gas barrier, reducing the effective filtration area; at the same time, the high content of dissolved oxygen will promote the growth of aerobic microorganisms on the surface of the reverse osmosis membrane to form biological pollution, or accelerate the oxidation and polymerization of organic matter in the wastewater, causing the reverse osmosis membrane flux to rapidly decay, forcing the plant to increase the frequency of chemical cleaning, significantly increasing the operation cost and chemical consumption. Therefore, there is an urgent need for a semiconductor industry wastewater treatment system to solve the above problems. SUMMARY

[0005] The present application aims to provide a semiconductor industry wastewater treatment system and configuration method by setting a gas-liquid separation device with cyclone separation, inert gas active replacement and anti-bubble interception function between the ultrafiltration device and the reverse osmosis device, which realizes the complete removal of the entrained bubbles in the UF effluent and the pre-removal of dissolved oxygen, effectively blocks the bubble impact on the RO high-pressure pump, and reduces the oxidation and biological pollution risk of the RO membrane, thereby improving the water quality and equipment operation stability of the wastewater reuse system.

[0006] The technical solution adopted by the present application to solve the above problems is: a semiconductor industry wastewater treatment system, comprising an ultrafiltration device, a reverse osmosis device, and a gas-liquid separation device arranged between the two; the gas-liquid separation device comprises:

[0007] a housing, the inside of the housing defines a gas phase region at the upper layer, a cyclone separation region at the middle layer, and a liquid phase region at the lower layer; the outside of the housing is provided with an exhaust port communicating with the gas phase region, a liquid inlet port communicating with the cyclone separation region, and a liquid outlet port communicating with the liquid phase region; the liquid inlet port is connected to the water production end of the ultrafiltration device, and the liquid outlet port is connected to the water inlet end of the reverse osmosis device;

[0008] a tangential inflow assembly arranged at the liquid inlet port and configured to introduce the fluid entering the housing along the tangential direction of the inner wall of the housing;

[0009] a flow guide assembly arranged in the cyclone separation region inside the housing, the flow guide assembly is arranged on the extension path of the outlet of the tangential inflow assembly and is configured to guide the fluid to form a circumferential rotational downward flow in the inner wall of the housing;

[0010] a gas sweeping assembly comprising a gas distributor extending into the gas phase region, the gas sweeping assembly is configured to access an external gas source and release protective gas into the gas phase region through the gas distributor;

[0011] a liquid outlet assembly comprising a pipe segment and an anti-vortex member connected to one end of the pipe segment, the other end of the pipe segment is connected to the liquid outlet port, the anti-vortex member is located inside the liquid phase region, the top of the anti-vortex member is closed and the side wall is provided with flow holes, and the anti-vortex member is configured to block the bubbles from the gas phase region and the liquid surface layer from entering the liquid outlet assembly.

[0012] In particular, the reverse osmosis device has a high-pressure pump, and a configuration method for the above semiconductor industry wastewater treatment system comprises the following steps:

[0013] The high-pressure pump suction stroke parameter of the reverse osmosis device and a preset safety margin value are acquired to determine the height value of the liquid phase region; the preset spiral flow channel slope value and the circumferential span value of the arc-shaped flow guide plate are acquired to determine the total drop value of the arc-shaped flow guide plate in the vertical direction, and the region with the total drop value is defined as the cyclone separation region; the remaining space in the shell is defined as the gas phase region;

[0014] The rated drainage flow rate Q of the ultrafiltration device is acquired, and a preset liquid film thickness δ of fluid flowing on the arc-shaped flow guide plate is set; the width W of the annular flow channel is determined according to the formula W=k1×Q / (V L ×δ), and the distance between the arc-shaped flow guide plate and the inner wall of the shell is configured according to the width W; wherein k1 is a correction coefficient, V L is a preset tangential flow rate, and the tangential flow rate V L is set to be greater than the minimum critical speed required for fluid to flow along the wall;

[0015] The Weber number W e is introduced as a gas-liquid disturbance criterion, and the formula is W e =(ρ g ×V rel 2 ×δ) / σ; wherein ρ g is the density of the protective gas of the external gas source, V rel is the gas-liquid relative speed, and σ is the surface tension of the wastewater; a Weber number W e value in a preset effective disturbance interval is selected, and the optimal gas flow impact speed V gasimpact is obtained by back calculation; the lower limit of the effective disturbance interval is the Weber number critical value at which ripples are generated on the liquid film surface, and the upper limit is the Weber number critical value at which droplets are splashed;

[0016] A vertical distance mapping relationship between the position of each jet hole of the gas distributor and the corresponding position of the arc-shaped flow guide plate below is established , wherein is the angular position in the circumferential direction; along the fluid flow direction, the hole diameter d of each jet hole is sequentially increased according to the increase of the vertical distance , so that the calculated impact speed of the gas flow reaching the liquid film surface via each jet hole is maintained at the optimal gas flow impact speed V gasimpact ; the center axis of each jet hole is configured to be inclined to the fluid incoming flow direction to form a counterflow injection angle.

[0017] The beneficial effects of the embodiments in the application are as follows:

[0018] 1. Because a gas-liquid separation device with a specific structure is installed between the ultrafiltration unit and the reverse osmosis unit, the tangential inlet component, together with the flow guide component in the cyclone separation area, forces the ultrafiltration effluent to form a circumferential rotating downward flow within the shell. Centrifugal force is used to effectively separate and precipitate the large number of microbubbles and supersaturated gases mixed in by ultrafiltration gas scrubbing in the water. In addition, the scavenging component releases protective gas in the gas phase region to replace the precipitated harmful gases and reduce the dissolved oxygen concentration. At the same time, the anti-vortex component with a closed top and open side walls in the liquid outlet component physically prevents the bubbles accumulated in the gas phase region and the liquid surface from being entrained into the downstream pipeline. Therefore, it effectively solves the technical problems in the prior art, such as cavitation vibration of the downstream reverse osmosis high-pressure pump caused by bubbles and high concentration of dissolved oxygen in the ultrafiltration effluent, gas resistance on the reverse osmosis membrane surface, and membrane flux decline caused by oxidation and biofouling. Thus, it achieves the technical effects of significantly improving the operational stability of the reverse osmosis system, extending the service life of the high-pressure pump and reverse osmosis membrane components, and reducing the frequency of chemical cleaning and operating costs.

[0019] 2. By adopting a structural parameter configuration method based on fluid dynamics matching and gas-liquid coupling critical criteria, the width of the annular flow channel adapted to the rated flow rate is accurately calculated to ensure stable thin liquid film adhering to the wall. The Weber number is used to define the effective range of airflow disturbance to prevent splashing. In particular, by establishing a vertical distance mapping relationship, the nozzle orifice diameter is increased sequentially along the fluid flow direction as the guide plate drop increases, and the counter-current injection angle is configured. Therefore, the technical problems of insufficient airflow disturbance attenuation in the downstream region, easy splashing and mist entrainment in the upstream region, and uneven liquid film mass transfer efficiency throughout the entire process caused by the change of gas-liquid distance in the spiral flow channel separation device are effectively solved. This achieves uniform distribution and efficient utilization of airflow jet energy throughout the spiral descending flow channel, maximizes the shear renewal frequency of the gas-liquid interface while preventing droplet splashing and contamination of the gas phase, and significantly improves the deep precipitation rate of dissolved oxygen and the overall degassing effect of the system. Attached Figure Description

[0020] Figure 1 A schematic cross-sectional view of an ultrafiltration device and a gas-liquid separation device according to an embodiment of the present invention is shown.

[0021] Figure 2 A schematic structural view of a gas distributor according to an embodiment of the present invention is shown.

[0022] Figure 3 A schematic top sectional view of a gas-liquid separation device according to an embodiment of the present invention is shown.

[0023] Figure 4 A schematic structural view of a liquid dispensing assembly according to an embodiment of the present invention is shown.

[0024] Figure 5 A schematic cross-sectional view of a liquid outlet assembly according to an embodiment of the present application is shown.

[0025] Figure 6 A schematic structural view of a gas-liquid separation device according to an embodiment of the present application is shown.

[0026] Wherein: 1, gas-liquid separation device; 110, housing; 111, gas phase region; 112, cyclonic separation region; 113, liquid phase region; 114, exhaust port; 115, liquid inlet; 116, liquid outlet; 120, tangential inlet assembly; 130, flow guide assembly; 140, sweep gas assembly; 141, gas distributor; 1411, jet hole; 150, liquid outlet assembly; 151, pipe section; 152, vortex prevention member; 1521, flow-through hole. DETAILED DESCRIPTION

[0027] The specific embodiments of the present application will be further described in detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0028] Referring to Figures 1 to 6 A semiconductor industry wastewater treatment system according to a preferred embodiment of the present application is provided, which is suitable for the reduction and reuse treatment of semiconductor wastewater containing fluorine, heavy metals and grinding wastewater. The existing typical semiconductor wastewater reuse process flow includes production wastewater collection, chemical precipitation pretreatment (such as coagulation and flocculation), multi-medium filtration, ultrafiltration device, intermediate water tank, reverse osmosis device, and the produced water is reused for cooling tower or as raw water for pure water station.

[0029] The semiconductor industry wastewater treatment system mainly consists of an ultrafiltration device, a reverse osmosis device, and a gas-liquid separation device 1 arranged between the two.

[0030] The gas-liquid separation device 1 comprises a shell 110, a tangential inlet assembly 120, a flow guide assembly 130, a sweep gas assembly 140 and a liquid outlet assembly 150, wherein the interior of the shell 110 defines an upper gas phase region 111, a middle cyclonic separation region 112 and a lower liquid phase region 113; the exterior of the shell 110 is provided with an exhaust port 114 communicating with the gas phase region 111, a liquid inlet port 115 communicating with the cyclonic separation region 112 and a liquid outlet port 116 communicating with the liquid phase region 113; the liquid inlet port 115 is connected to the water production end of an ultrafiltration device, and the liquid outlet port 116 is connected to the water inlet end of a reverse osmosis device; the tangential inlet assembly 120 is arranged at the liquid inlet port 115 and is configured to introduce the fluid entering the shell 110 along the tangential direction of the inner wall of the shell 110; the flow guide assembly 130 is arranged in the cyclonic separation region 112 inside the shell 110, and is arranged on the extension path of the outlet of the tangential inlet assembly 120 and is configured to guide the fluid to form a circumferential direction rotating downward flow in the inner wall of the shell 110; the sweep gas assembly 140 comprises a gas distributor 141 extending into the gas phase region 111, and is configured to access an external gas source and release protective gas into the gas phase region 111 through the gas distributor 141; the liquid outlet assembly 150 comprises a pipe segment 151 and a vortex prevention member 152 connected to one end of the pipe segment 151, the other end of the pipe segment 151 is connected to the liquid outlet port 116, and the vortex prevention member 152 is located inside the liquid phase region 113, the top of the vortex prevention member 152 is closed and the side wall is provided with flow holes 1521, and the vortex prevention member 152 is configured to block the gas bubbles from the gas phase region 111 and the surface layer of the liquid from entering the liquid outlet assembly 150.

[0031] The shell 110 is a sealed structure, which is spatially divided into three functional regions: the gas phase region 111 at the top for accommodating separated gas and injected protective gas; the cyclonic separation region 112 in the middle for performing gas-liquid centrifugal separation; and the liquid phase region 113 at the bottom for storing the liquid after degassing treatment. The outer wall surface of the shell 110 is provided with three main process interfaces: the exhaust port 114 communicating with the gas phase region 111 for discharging the separated gas; the liquid inlet port 115 communicating with the cyclonic separation region 112, which is directly connected to the water production end of the upstream ultrafiltration device through a pipeline; and the liquid outlet port 116 communicating with the liquid phase region 113, which is connected to the water inlet end of the downstream reverse osmosis device through a pipeline (usually connected to the inlet of a high-pressure pump).

[0032] A tangential inlet assembly 120 is arranged at the liquid inlet 115, which is configured to enable the fluid from the ultrafiltration device to enter along the tangent direction of the inner wall of the housing 110, so as to obtain initial rotational kinetic energy. A flow guide assembly 130 is arranged in the cyclone separation area 112 inside the housing 110, which is arranged on the extended path of the outlet of the tangential inlet assembly 120, and is configured to be adapted to the inner wall of the housing 110, so as to receive the tangentially entered fluid and guide it to form a downward rotating flow along the circumferential direction of the inner wall of the housing 110, thereby prolonging the path of the fluid in the separation area and maintaining the centrifugal force.

[0033] In order to control the gas phase environment, the device is provided with a sweep gas assembly 140, which includes a gas distributor 141 extending to the gas phase area 111 inside the housing 110. The sweep gas assembly 140 is configured to access an external inert gas source (such as nitrogen), and uniformly release the protective gas to the gas phase area 111 through the gas distributor 141, so as to cover the liquid surface. The liquid outlet assembly 150 is arranged in the liquid phase area 113 at the bottom of the housing 110, which includes a pipe section 151 connected to the liquid outlet 116 and an anti-vortex member 152 installed at the inlet end of the pipe section 151. The anti-vortex member 152 is located below the liquid surface, and the top thereof is designed as a closed structure, and a flow hole 1521 is arranged on the side wall, which is configured to physically block the gas in the gas phase area 111 and the foam or bubbles possibly existing on the surface of the liquid surface from being directly sucked into the downstream pipeline.

[0034] During operation, the water produced by the ultrafiltration device enters the housing 110 through the tangential inlet assembly 120 at the liquid inlet 115 at a high speed in a tangential direction. Under the guidance of the flow guide assembly 130, the water flow rotates downward at a high speed close to the inner wall of the housing 110. By using the centrifugal force generated by the density difference between gas and liquid, the micro-bubbles entrained in the water body move to the center and float upward to the gas phase area 111, while the degassed water flow flows downward along the wall into the liquid phase area 113. At the same time, the sweep gas assembly 140 continuously introduces protective gas into the gas phase area 111, which reduces the oxygen partial pressure in the gas phase, thereby breaking the gas-liquid equilibrium, promoting the further precipitation of dissolved oxygen in the water body, and preventing external air from being dissolved again.

[0035] In particular, when the upstream ultrafiltration device performs a gas scouring or backwashing procedure, the fluid state entering the gas-liquid separation device 1 changes dramatically, showing a sudden surge in flow rate and a large amount of high-density gas-water mixed foam entrained in the water flow. Under this working condition, the tangential inflow assembly 120 and the flow guide assembly 130 use the sudden surge in flow rate to generate stronger centrifugal force, forcing the gas-water mixed flow to be thrown against the barrel wall, thereby quickly breaking up large gas bubbles; the separated gas quickly rises. Although the liquid surface may produce violent fluctuations or accumulate thick layers of foam at this time, since the liquid outlet assembly 150 is provided with a vortex prevention member 152, the closed top of the member acts like a shield to block the entrainment effect of the fluctuation of the upper liquid surface, forcing the water flow to only enter the liquid outlet pipe smoothly from the flow-through holes 1521 of the side wall. This ensures that even under the most severe working conditions of ultrafiltration backwashing, the water flow delivered to the downstream reverse osmosis device is still a smooth liquid flow without gas bubbles.

[0036] The system is designed for semiconductor factory wastewater treatment. Since the semiconductor wastewater may contain corrosive substances (such as fluoride ions, acid and alkali residues), the shell 110 and internal components (flow guide assembly 130, vortex prevention member 152) are usually made of corrosion-resistant materials, such as stainless steel or carbon steel lined with special coatings. The system is suitable for scenarios with strict requirements on dissolved oxygen content and the need to protect reverse osmosis high-pressure pumps from cavitation. The working environment usually requires normal temperature, and the shell 110 design needs to be able to withstand the excess pressure of ultrafiltration water and the back pressure of the exhaust system.

[0037] In this embodiment, by setting a gas-liquid separation device 1 with a specific structure between the ultrafiltration device and the reverse osmosis device, using the tangential inflow assembly 120 in cooperation with the flow guide assembly 130 in the cyclone separation area 112 to force the ultrafiltration water to form a circumferential rotational descending flow in the shell 110, using centrifugal force to effectively separate and precipitate a large amount of micro-bubbles and supersaturated gas mixed in the water body during ultrafiltration gas scouring, and cooperating with the scavenging assembly 140 to release protective gas in the gas phase area 111 to replace the precipitated harmful gas and reduce the dissolved oxygen concentration, while using the vortex prevention member 152 in the liquid outlet assembly 150, which has a closed top and open side wall, to physically block the gas bubbles accumulated in the gas phase area 111 and the surface layer of the liquid from being sucked into the downstream pipeline, the technical problems of cavitation vibration of the downstream reverse osmosis high-pressure pump, gas blockage on the surface of the reverse osmosis membrane, and membrane flux decay due to oxidation and biological fouling caused by the entrainment of gas bubbles and high concentration of dissolved oxygen in the ultrafiltration water in the prior art are effectively solved, thereby achieving the technical effects of significantly improving the operation stability of the reverse osmosis system, prolonging the service life of the high-pressure pump and the reverse osmosis membrane assembly, and reducing the frequency of chemical cleaning and operating costs.

[0038] Further, in some embodiments, referring to Figure 3The flow guide assembly 130 comprises an arc-shaped flow guide plate fixed to the inner wall of the housing 110 and extending along the circumferential direction of the housing 110. The arc-shaped flow guide plate and the inner wall of the housing 110 form an annular flow channel. The inlet end of the annular flow channel is opposite to the jet direction of the tangential inflow assembly 120. The lower edge of the arc-shaped flow guide plate extends below the center line horizontal plane of the tangential inflow assembly 120 and below the designed minimum liquid level of the liquid phase region 113.

[0039] The arc-shaped flow guide plate is generally made of metal or engineering plastic plate with certain rigidity and corrosion resistance, and its geometric shape is matched with the curvature of the inner cylindrical surface of the housing 110. The arc-shaped flow guide plate is installed on the inside of the housing 110 by welding or bracket fastening, but it is not completely closed, but maintains a predetermined gap between the arc-shaped flow guide plate and the inner wall of the housing 110, so as to form an annular flow channel with a certain width between the inner surface of the flow guide plate and the surface of the inner wall of the housing 110.

[0040] The spatial layout of the annular flow channel is precisely designed. The opening position and direction of the inlet end are configured to be opposite to the jet direction of the tangential inflow assembly 120. This means that the fluid sprayed at high speed from the tangential inflow assembly 120 has a smooth connection in space with the direction of the extension tangent of the annular flow channel, and there is no obvious impact angle. In the vertical direction, the arc-shaped flow guide plate has a significant extension feature: the upper edge is usually higher than or flush with the inflow port, and the lower edge extends downward. Specifically, the lower edge of the arc-shaped flow guide plate not only extends below the center line horizontal plane of the tangential inflow assembly 120 to ensure that the lower half of the jet beam is completely received, but also extends downward to below the designed minimum liquid level of the liquid phase region 113. This structure actually forms a semi-closed spiral slide or vertical flow guide groove from the gas phase space to the liquid phase space.

[0041] In actual work, when the high-speed water flow carrying gas bubbles is injected from the tangential inflow assembly 120, the water flow does not directly impact the wall of the housing 110 or directly fall to the lower liquid surface, but seamlessly cuts into the annular flow channel formed by the arc-shaped flow guide plate and the inner wall of the housing 110. Due to the constraint of the annular flow channel, the water flow is forced to be arranged as a flat wall flow, and rotates at high speed along the circumferential direction of the housing 110 by relying on its tangential kinetic energy.

[0042] In this process, the arc-shaped guide plate restricts the radial diffusion of the water flow to the center of the shell 110, forcing the fluid to maintain a high-intensity centrifugal motion, thereby maximizing the centrifugal force field of gas-liquid separation. Under the action of gravity, the rotating water flow spirals downward along the annular flow channel. Since the lower edge of the arc-shaped guide plate extends below the designed minimum liquid level, the high-speed rotating water flow is eventually released into the liquid phase area 113 below the liquid surface. This submerged release method avoids the violent turbulence and splashing caused by the direct drop of the water flow from a high altitude onto the liquid surface, preventing the gas in the gas phase space from being re-entrained into the water.

[0043] This structural design needs to be used with a liquid level control system to ensure that the liquid level of the liquid phase area 113 always submerges the lower edge of the arc-shaped guide plate during normal operation, thereby maintaining the liquid seal effect.

[0044] In this embodiment, by using the arc-shaped guide plate fixed to the inner wall of the shell 110 and forming an annular flow channel, and particularly configuring the lower edge of the guide plate to extend below the centerline of the tangential inlet assembly 120 and below the designed minimum liquid level of the liquid phase area 113, the technical problems of low centrifugal separation efficiency due to early diffusion of the fluid after tangential entry in the prior art, as well as splashing and secondary gas entrainment caused by direct drop impact on the liquid surface, are effectively solved, thereby realizing stable and splash-free submersion of the fluid into the liquid phase area 113 while ensuring high-intensity centrifugal separation effect, significantly reducing the gas content of the separated liquid, and eliminating the water drop noise.

[0045] Further, in some embodiments, referring to Figures 1 to 2 , the gas distributor 141 is configured as an annular spray pipe arranged along the inner periphery of the gas phase area 111; a plurality of spray holes 1411 are formed on the annular spray pipe, the opening direction of the spray holes 1411 is inclined towards the inner wall of the shell 110, and each spray hole 1411 is configured to form an annular gas curtain in the gas phase area 111. The extension line of the central axis of the spray hole 1411 passes through the width center region of the annular flow channel.

[0046] The annular spray pipe is usually made of corrosion-resistant metal (such as stainless steel) or high-strength polymer material, and has a hollow circular pipe structure. In the installed position, the annular spray pipe is arranged horizontally along the top inner periphery edge of the gas phase area 111 of the shell 110, and is fixed to the top or inner wall of the shell 110 by a hanger or support. A series of spray holes 1411 are uniformly formed on the pipe wall of the annular spray pipe in the circumferential direction, and these spray holes 1411 are not vertically downward, but are designed to have a specific inclination angle, i.e., the opening direction is inclined towards the inner wall of the shell 110.

[0047] In order to realize the precise docking of the gas-liquid interface, the geometric direction of the above-mentioned spray hole 1411 is strictly limited: the extension line of the center axis of each spray hole 1411 precisely passes through the width center area of the annular flow channel. The annular flow channel here is the path of the fluid rotating along the inner wall of the shell 110, and the width center area is usually the position where the liquid film flow is most stable and the thickness is most uniform. According to the process requirements, the spray hole 1411 can be designed as a simple drill hole, or a precision atomizing nozzle or a fan-shaped nozzle can be installed to control the diffusion form of the gas flow.

[0048] During operation, external protective gas (such as inert gas) is pumped into the annular spray pipe to establish a certain internal pressure. The gas is then sprayed out at high speed from a number of spray holes 1411 distributed in the annular direction. Because the spray hole 1411 has an inclination angle towards the inner wall of the shell 110, the sprayed gas flow forms a series of jet beams radiating outward and downward. With the diffusion of the jet, the gas flow sprayed by adjacent spray holes 1411 overlaps and merges in space, and finally forms a continuous annular gas curtain with a certain impact force at the edge of the gas phase area 111, close to the inner wall of the shell 110.

[0049] Because the center axis of the spray hole 1411 passes through the width center area of the annular flow channel, this annular gas curtain can accurately cover and impact the liquid surface rotating and flowing obliquely downward. The gas flow directly strikes the center area of the liquid flow, not only can use the kinetic energy of the gas flow to blow the liquid surface and destroy the liquid surface boundary layer, but also can use the partial pressure principle to quickly displace the dissolved gas precipitated from the liquid. This directional gas flow protection barrier is like a layer of flowing inert gas cover on the rotating water flow, effectively isolating the air that may remain in the space above.

[0050] In this embodiment, because the annular spray pipe arranged along the inner periphery of the gas phase area 111 is used as the gas distributor 141, and the spray hole 1411 is inclined towards the inner wall of the shell 110 and its axis extension line passes through the width center area of the annular flow channel, a directional annular gas curtain is formed in the gas phase area 111, thereby effectively solving the technical problems of uneven gas distribution in the prior art, which leads to the failure of the protective gas to accurately cover the liquid surface, and the incomplete replacement of dissolved oxygen due to the contact dead angle, and further realizing the full- range accurate contact between the protective gas and the rotating liquid surface, significantly improving the dissolution gas precipitation efficiency, and constructing a high-efficiency physical isolation barrier to prevent the secondary dissolution of the gas.

[0051] Further, in some embodiments, referring to Figure 5 The flow-through hole 1521 of the vortex prevention member 152 in the liquid outlet assembly 150 is designed with specific fluid mechanics parameters. The total flow-through area of all the flow-through holes 1521 is set to be 3 to 5 times larger than the cross-sectional area of the pipe segment 151.

[0052] The total flow area of all the flow-through holes 1521 on the sidewall of the vortex prevention member 152 is strictly set to be 3 to 5 times larger than the cross-sectional area of the vertical pipe segment 151. This ratio is not randomly selected, but is a key engineering parameter calculated based on the fluid continuity equation and the local head loss. In terms of structure, it means that the sidewall of the vortex prevention member 152 has a high open hole rate, or the overall size (diameter or height) of the vortex prevention member 152 is significantly larger than the outlet pipe diameter, thereby forming a large flow capacity hydraulic buffer chamber around the inlet of the outlet pipe.

[0053] The core working principle of this structural design is to significantly reduce the local flow rate by using the area difference. According to the principle of fluid mechanics, the flow rate is inversely proportional to the flow area under the same flow rate. When the fluid passes through the flow-through holes 1521 on the sidewall of the vortex prevention member 152 from the outside to the inside pipe segment 151, the average flow rate at the flow-through holes 1521 is only one-third to one-fifth of the flow rate in the pipe segment 151 due to the total area of the flow-through holes 1521 being three to five times larger than the cross-sectional area of the pipe segment 151.

[0054] This significant reduction in flow rate plays a crucial role in dealing with the backwashing or air scouring condition of the upstream ultrafiltration device. When the ultrafiltration device is backwashed, the system water inflow will suddenly increase, causing the liquid level of the liquid phase region 113 to fluctuate dramatically. If the flow-through holes 1521 have a small area (e.g., comparable to the pipe diameter area), the sudden increase in flow rate will cause the flow rate at the flow-through holes 1521 to rise sharply, generating a strong local negative pressure (Venturi effect), which is likely to suck the foam layer or micro-bubbles at the gas-liquid interface above the vortex prevention member 152 into the pipe like a "dust collector". By expanding the flow area to three to five times, a low-flow safety inlet area is created. Even under the condition of sudden flow increase, the actual flow rate at the flow-through holes 1521 remains at a very low level, and the water flows into the vortex prevention member 152 in a gentle, laminar state rather than a jet, thereby completely eliminating the kinetic energy basis for generating suction vortex in terms of hydraulics.

[0055] In alternative embodiments, this three to five times flow area can be achieved by adjusting the hole size of the flow-through holes 1521, or by increasing the number of flow-through holes 1521. The shape of the holes can be circular, long strip-shaped or grid-shaped, as long as the total area meets the above ratio requirement.

[0056] In this embodiment, by adopting the technical means of setting the total flow-through area of all flow-through holes 1521 on the vortex-preventing member 152 to be three to five times larger than the cross-sectional area of the pipe segment 151, the technical problem of the existing technology that the sudden surge of upstream flow (such as the reverse washing working condition of ultrafiltration) causes the Venturi effect due to the excessively high local flow rate at the water outlet, and then the air bubbles and foam on the surface of the liquid level are sucked into the downstream pipeline, is effectively solved, and the technical effect of forming a hydraulic buffer by using a significantly reduced inlet flow rate is achieved, and the water outlet can still be a stable single-phase flow when the liquid level fluctuates violently, and the damage of air bubbles to the downstream reverse osmosis high-pressure pump due to cavitation is prevented.

[0057] Further, in some embodiments, referring to Figure 1 The vertical installation position of the vortex-preventing member 152 in the liquid phase region 113 in the liquid outlet assembly 150 is strictly limited in safety. The top position of the vortex-preventing member 152 is configured to be at least 100 mm lower than the designed minimum liquid level of the liquid phase region 113.

[0058] The top of the vortex-preventing member 152 (i.e., the upper surface of its closed cover plate) is configured to be below the designed minimum liquid level of the liquid phase region 113, and the height difference between them is at least one hundred millimeters. The designed minimum liquid level here does not refer to the physical bottom of the shell 110, but refers to the limit threshold of the allowed liquid level drop set in the control system, which usually corresponds to the low liquid level control point at which the liquid level sensor triggers the pump protection or water replenishment signal. In terms of physical structure, this means that the vortex-preventing member 152 is submerged below the liquid level, and even when the system liquid level is running to the allowed minimum limit, there is still a layer of pure water protection with a thickness of not less than one hundred millimeters above the top of the vortex-preventing member 152.

[0059] The core working principle of this position parameter setting is to ensure that the critical submergence depth is always met to suppress the formation of free surface vortex by using hydrostatic pressure. According to the principle of fluid mechanics, when the water outlet at the bottom of the container is too close to the liquid level, the suction effect of the water outlet will form a funnel-shaped vortex at the liquid level, causing air to be sucked in. Especially in this system, when the upstream ultrafiltration device is in the reverse washing or high-flow water production working condition, the flow rate fluctuation will cause the turbulence intensity of the liquid phase region 113 to increase significantly. If the vortex-preventing member 152 is just submerged in water, the top of the vortex-preventing member 152 is easily exposed by the violent liquid level fluctuation, or an air suction vortex penetrating the liquid layer is induced due to the decrease of local dynamic pressure.

[0060] A liquid level difference of at least 100 mm is set, which in fact builds a rigid hydraulic safety margin. The water column with a thickness of at least 100 mm provides sufficient hydrostatic pressure to effectively offset the dynamic pressure drop caused by water outlet suction. Even in the case of detection lag of the liquid level sensor or large amplitude fluctuation of the liquid surface due to sudden change of water inlet flow, the safety water seal can ensure that bubbles or foam on the surface of the liquid layer cannot penetrate the water layer into the water intake range of the vortex prevention member 152. This is crucial for protecting the downstream reverse osmosis high-pressure pump, because even a momentary air vortex can cause cavitation damage to the high-pressure pump.

[0061] In optional embodiments, the 100 mm distance can be adjusted according to the actual water outlet pipe diameter and flow rate. For large-diameter high-flow systems, the distance is usually designed to be larger (e.g. 150 mm or 200 mm). In addition, a mechanical limit switch or photoelectric liquid level meter can be set to hard lock this minimum liquid level. Once the liquid level approaches the 100 mm red line, the system will forcibly cut off the power supply of the water outlet pump.

[0062] In this embodiment, by configuring the top position of the vortex prevention member 152 to be lower than the liquid phase region 113 and designing the minimum liquid level to be at least 100 mm, the technical problem of air penetrating into the downstream pipeline due to insufficient critical submergence depth and inducing penetrating air vortex caused by liquid level control lag or upstream ultrafiltration backwash flow fluctuation in the prior art is effectively solved. Thus, a stable hydraulic sealing layer can be maintained under any extreme low liquid level condition, air suction caused by liquid level fluctuation or vortex entrainment is prevented, and the absolute continuity and pure phase of the reverse osmosis system high-pressure water inlet are ensured.

[0063] Further, in some embodiments, the gas-liquid separation device 1 is equipped with a complete atmosphere control and pressure maintenance subsystem. The gas-liquid separation device 1 further comprises an inert gas source connected to the scavenging assembly 140, and a pressure regulating assembly connected to the exhaust port 114; the wastewater treatment system is configured to maintain the gas phase region 111 in a positive pressure state through the pressure regulating assembly, and to replace dissolved oxygen and bubbles emitted from the cyclone separation region 112 and the liquid phase region 113 using the scavenging assembly 140.

[0064] The inert gas source is usually selected from a high-purity nitrogen generator, a liquid nitrogen storage tank, or a nitrogen delivery pipe network. The inert gas source is physically connected to the gas inlet end of the scavenging assembly 140 through a gas supply pipeline, which usually has a flow meter and a pressure reducing valve to control the gas inlet amount.

[0065] At the same time, a pressure regulating assembly is connected at the exhaust port 114 of the shell 110. The pressure regulating assembly is usually configured as a high-precision back pressure valve, a micro pressure regulating valve, or an automatic control loop composed of a pressure sensor and an electric regulating valve. The pressure regulating assembly is configured to monitor and regulate the absolute pressure in the gas phase region 111 of the shell 110. The entire wastewater treatment system is integrated with a central controller, which is logically programmed to coordinate the opening of the inert gas source and the opening of the pressure regulating assembly, thereby building a dynamically balanced gas phase control environment.

[0066] During system operation, the inert gas source continuously injects nitrogen or other inert gas into the gas phase region 111 of the shell 110. According to Henry's law, the solubility of a gas in water is proportional to its partial pressure at the gas-liquid interface. The injected inert gas forms a low-oxygen or even oxygen-free environment above the liquid surface, breaking the gas-liquid equilibrium of dissolved oxygen in water and forcing the remaining dissolved oxygen in the water body to escape to the gas phase space.

[0067] In this process, the pressure regulating assembly plays a key role. It dynamically adjusts the opening of the exhaust port 114 according to the preset control strategy. When the pressure in the gas phase region 111 is lower than the preset positive pressure threshold, the pressure regulating assembly closes or closes the exhaust passage, and uses the continuously injected inert gas to build pressure; when the pressure exceeds the threshold, the assembly is moderately opened, and the displaced oxygen, entrained micro-bubble exhaust gas, and excess inert gas are discharged together. This control logic always maintains the gas phase region 111 in a slightly positive pressure state (i.e., the internal pressure is slightly higher than the external atmospheric pressure), ensuring that the gas flow direction is always from inside to outside, thereby physically building a one-way air shield.

[0068] In this embodiment, by using the inert gas source connected to the scavenging assembly 140 in combination with the pressure regulating assembly connected to the exhaust port 114, and by maintaining the gas phase region 111 in a positive pressure state through the control strategy and continuously displacing the dissolved gas with flowing inert gas, the technical problems of incomplete removal of dissolved oxygen due to high oxygen partial pressure in the gas phase space and contamination of the water body by external oxygen-containing air due to transient negative pressure caused by liquid level fluctuations in the prior art are effectively solved, thereby achieving the technical effects of deep removal of dissolved oxygen in wastewater using partial pressure principle and building a zero-oxygen positive pressure barrier to prevent secondary dissolution of oxygen, thereby significantly delaying the oxidation degradation and biological growth of the downstream reverse osmosis membrane.

[0069] The reverse osmosis device has a high-pressure pump. A configuration method for the above-mentioned semiconductor industry wastewater treatment system includes the following steps:

[0070] Step S100: Obtain the high-pressure pump suction stroke parameter of the reverse osmosis device and the preset safety margin value to determine the height value of the liquid phase region 113; obtain the preset spiral flow channel slope value and circumferential span value of the arc-shaped flow guide plate to determine the total drop value of the arc-shaped flow guide plate in the vertical direction, and the region with the total drop value is defined as the cyclone separation region 112; the remaining space in the shell 110 is defined as the gas phase region 111;

[0071] Step S200: Obtain the rated drainage flow rate Q of the ultrafiltration device, and set the preset liquid film thickness δ of the fluid flowing on the arc-shaped flow guide plate; determine the width W of the annular flow channel according to the formula W=k1×Q / (V L ×δ), and configure the distance between the arc-shaped flow guide plate and the inner wall of the shell 110 according to the width W; wherein k1 is a correction coefficient, V L is a preset tangential flow rate, and the tangential flow rate V L is set to be greater than the minimum critical speed required for the fluid to flow along the wall;

[0072] Step S300: Introduce the Weber number W e as a gas-liquid disturbance criterion, the formula is W e =(ρ g ×V rel 2 ×δ) / σ; wherein ρ g is the protective gas density of the external gas source, V rel is the gas-liquid relative speed, and σ is the surface tension of the wastewater; select a Weber number W e value within a preset effective disturbance interval, and the optimal gas flow impact speed V gasimpact is obtained by back calculation; the lower limit of the effective disturbance interval is the Weber number critical value at which the liquid film surface produces ripples, and the upper limit is the Weber number critical value at which droplets splash;

[0073] Step S400: Establish the vertical distance mapping relationship between the position of each jet hole 1411 of the gas distributor 141 and the corresponding position of the arc-shaped flow guide plate below , wherein is the angular position in the circumferential direction; along the fluid flow direction, according to the increase of the vertical distance , the hole diameter d of each jet hole 1411 is sequentially increased, so that the calculated impact speed of the gas flow ejected through each jet hole 1411 to the liquid film surface is maintained at the optimal gas flow impact speed V gasimpact ; the center axis of each jet hole 1411 is configured to be inclined to the fluid incoming flow direction to form a counterflow injection angle.

[0074] Specifically:

[0075] Step S100 is used to construct the longitudinal space of the inner region of the shell 110 and divide the model, wherein:

[0076] The determination method of the liquid phase region 113 height value is as follows:

[0077] Firstly, the high-pressure pump suction parameter is determined, which can be obtained by consulting the product technical specification book or performance curve atlas of the high-pressure pump matched with the selected type of reverse osmosis device. Specifically, the necessary net positive suction head under the rated working condition flow of the pump needs to be obtained. This parameter is determined by the pump manufacturer through experiment, which represents that in order to prevent the pump from being gas-eroded, the fluid at the pump suction inlet must have a minimum energy head exceeding the saturated steam pressure.

[0078] Secondly, the preset safety margin value is determined, which is determined according to the pipeline hydraulic loss and engineering experience. The value is usually composed of two parts: the first part is the pipeline resistance loss, that is, the sum of the resistance along the pipeline, valves and bends between the liquid outlet 116 of the gas-liquid separation device 1 and the suction inlet of the high-pressure pump; the second part is the engineering safety margin, which is usually 0.5-1.0 meters of water column, which is used to offset the liquid level sensor fluctuation error and prevent vortex gas absorption under the critical state.

[0079] Wherein:

[0080] The pipeline resistance loss includes the sum of the resistance along the pipeline, valves and bends between the liquid outlet 116 of the gas-liquid separation device 1 and the suction inlet of the high-pressure pump, which is denoted as , which needs to be calculated by using the Darcy formula in fluid mechanics combined with the local resistance coefficient method.

[0081] The specific steps are as follows:

[0082] The resistance along the pipeline is calculated according to the formula .

[0083] Wherein, is the resistance coefficient along the pipeline (obtained according to the roughness of the pipeline material and the Reynolds number from the Moody diagram), is the total length of the straight pipe section 151, is the inner diameter of the pipeline, is the average flow velocity in the pipeline, is the acceleration of gravity.

[0084] The local resistance is calculated: the number of all bends, tees, reducers and valves (fully open state) in the pipeline is counted.

[0085] According to the Water Power Calculation Manual or the valve manufacturer's parameters, the corresponding local resistance coefficients of each are obtained, and the total local resistance is calculated according to the formula .

[0086] Total resistance summation: the above are added, i.e. the total resistance loss head of the pipeline system, i.e. the pipeline resistance loss.

[0087] The value is not randomly selected, but an empirical value determined based on the design specifications for the suction side of a centrifugal pump and the critical submergence depth theory.

[0088] The determination basis is as follows:

[0089] Offset liquid level fluctuation: considering that the sudden increase in flow during ultrafiltration backwashing will cause dynamic waves on the liquid surface, the difference between the wave crest and the wave trough can reach 200-300mm, and a margin needs to be reserved.

[0090] Cover sensor dead zone: industrial liquid level sensors (such as static pressure or ultrasonic) usually have a measurement blind zone or lag error, usually 100-200mm.

[0091] Prevent suction vortex: according to the critical submergence depth empirical formula (H = 4.64DFr2) , where D is the pipe diameter and Fr is the Froude number), to prevent the liquid surface from generating a penetrating suction vortex, an additional safety water depth needs to be added to the theoretical calculation value.

[0092] Taking the lower limit of 0.5m in systems with low flow rate (<1m / s) and short pipelines, and taking the upper limit of 1.0m in systems with high flow rate (>1.5m / s) or severe liquid level fluctuation.

[0093] The height value of the liquid phase region 113 should at least include the design minimum liquid level height and the effective volume height.

[0094] First, the minimum liquid level height should be calculated: .

[0095] The minimum liquid level height formula is an engineering application formula derived based on the standard effective cavitation allowance definition formula in fluid mechanics, and is common knowledge. The original formula is: see the section on pump cavitation in the Pump Manual or Fluid Mechanics textbook. The standard formula is: . The derivation process is: to ensure that the pump does not cavitate, it is required that . In this system, assuming that the pressure in the gas phase region 111 is atmospheric pressure or slightly positive pressure , and ignoring the saturation vapor pressure of normal temperature water (which is a small value as an additional safety factor), the static pressure head (i.e. the here) must overcome the pipeline loss​ And provide the pump required . To ensure reliability, an additional engineering safety margin.

[0096] Second, according to the system required buffer time (for example, 1 to 2 minutes of water buffer volume) and the shell 110 cross-sectional area, the effective volume required height.

[0097] Where: the effective volume required height calculation method based on the volume and flow time integral relationship, the specific calculation steps are as follows:

[0098] Get parameters, determine the reverse osmosis device water flow (unit: ), set the buffer time (for example, 1 / 60 hours, that is, 1 minute), and the shell 110 liquid phase area 113 of the inner cross-sectional area (unit: ).

[0099] Calculate the buffer volume: .

[0100] Calculate the height: according to the formula of the volume of the cylinder , the effective volume height . Example: if the RO water flow is , buffer 1 minute (need water), the shell 110 diameter 1 meters (area about ), the required buffer height meters.

[0101] Finally, the above two superposition, determine the liquid phase area 113 in the shell 110 vertical direction required minimum total height, in this way as the liquid phase area 113 height value of the defining basis.

[0102] The determination method of cyclone separation area 112 height value is described as follows:

[0103] First, is the arc baffle pre-set parameters, including:

[0104] Spiral flow channel slope value ( ): the value based on fluid mechanics simulation or empirical data, defined as the tangent direction of the arc baffle and the angle between the horizontal plane. In order to ensure that the fluid can smoothly down and not to accumulate liquid, and can maintain enough rotation residence time, the slope value is usually obtained between 5 degrees to 15 degrees of a fixed value.

[0105] Wherein, 5 degrees to 15 degrees slope value selection mechanism is based on the balance relationship between the sliding mechanics and gas-liquid separation residence time is determined.

[0106] The lower limit of 5 degrees is based on the fact that the angle of repose of water on a smooth stainless steel surface, or the minimum drainage slope, is usually very small (approximately 1 to 2 degrees). 5 degrees is chosen to ensure that the component of gravity along the inclined plane (…) The frictional resistance between the fluid and the plate surface is significantly greater than that between the fluid and the plate surface. This ensures that no water remains on the board when the machine is stopped and drained, thus preventing the growth of bacteria.

[0107] The basis for the 15-degree upper limit (to ensure residence time) is that the greater the slope, the faster the vertical velocity of the fluid descends, the shorter the spiral path length on the plate surface, and the shorter the residence time for gas-liquid separation. Fluid dynamics experiments show that when the slope exceeds 15 degrees, the fluid tends to slide down rapidly rather than rotate, leading to a sharp decrease in centrifugal separation efficiency. Conclusion: 5 degrees to 15 degrees is the optimal engineering range for ensuring gravity-flow drainage and maximizing the separation path.

[0108] It should be noted that the aforementioned fluid dynamics experiments were conducted by the inventors of this application through comparative model experiments with different spiral channel slopes. The results showed that the separation efficiency of the fluid on the guide plate mainly depends on the product of the centrifugal separation factor and the hydraulic residence time. Experimental data showed that when the spiral channel slope exceeds 15 degrees, the component of gravity along the tangential direction of the channel increases significantly, leading to a sharp increase in the axial velocity of the fluid and a nonlinear decay of the hydraulic residence time. The fluid exhibits a rapid sliding rather than fully swirling flow pattern, resulting in insufficient time for microbubbles to overcome liquid film resistance and precipitate. Conversely, when the slope is less than 5 degrees, the fluid velocity is too low to generate sufficient centrifugal force and easily leads to liquid accumulation during shutdown. Therefore, based on fluid dynamics experimental verification, this embodiment limits the spiral channel slope to the optimal range of 5 to 15 degrees.

[0109] The above fluid mechanics experiments can be conducted according to the following steps:

[0110] First, the experimental setup is constructed, including:

[0111] Model construction: Build a cylindrical shell 110 (inner diameter D=500mm) made of transparent acrylic material, and install a detachable and replaceable arc-shaped guide plate model inside.

[0112] Variable settings, prepare 5 sets of different spiral slopes ( The guide vanes have slopes of 3°, 10°, 15°, 20°, and 30°. The circumferential span of all guide vanes is fixed at 270°, and the channel width W is fixed at 100mm.

[0113] Fluid operating conditions: Dissolved air water (simulating ultrafiltration backwash water) is used, and the influent flow rate is constant. The gas content (by volume) in the influent is adjusted to 5%.

[0114] Observation equipment: High-speed camera was configured to capture the liquid flow trajectory; online dissolved oxygen meter (DO meter) and bubble counter were configured to detect the outflow indicators.

[0115] Secondly, the specific experimental steps include:

[0116] Step one, install the guide plates with different slopes in sequence;

[0117] Step two, turn on the water inlet pump, and after the flow state is stable, inject pulse tracer (such as red ink or brine) into the water inlet, and use a high-speed camera to record the actual residence time of the fluid from the inlet to the liquid surface;

[0118] Step three, observe and record the wall adhesion state of the liquid flow on the guide plate. Focus on observing whether there is a slip phenomenon (i.e. the fluid separates from the spiral trajectory and directly flows downward) or a splashing phenomenon;

[0119] Step four, collect the separated outflow samples, measure the number of residual bubbles and the dissolved oxygen concentration, and calculate the gas-liquid separation efficiency (η) ).

[0120] Then, analyze the experimental results and data, including:

[0121] The experimental data are recorded as follows (inductive description):

[0122] Group A (slope 3°): The fluid flow is extremely slow, the centrifugal force is insufficient ( ), and the fluid appears to accumulate and flow on the plate surface, which cannot form a stable rotating liquid film, and is difficult to empty. Conclusion: The slope is too small.

[0123] Group B (slope 10°) and Group C (slope 15°): The fluid forms a perfect wall-adhesion liquid film with uniform thickness (about 3-5 mm). High-speed photography shows that the tracer moves along a strict spiral path, and there is no obvious longitudinal slip. The residence time of the fluid on the plate is long enough ( ), and the bubbles have sufficient time to drift to the center under the action of centrifugal force and separate out. The bubble removal rate reaches the highest peak (> 95%).

[0124] Group D (slope 20°) and Group E (slope 30°): The slip phenomenon occurs, and high-speed photography shows that the gravity component along the slope ( ) of the fluid increases significantly. The longitudinal velocity component ( ) of the fluid particles increases sharply, causing the fluid to no longer move strictly along the spiral line, but to show a large-pitch rapid slip trend. The actual residence time decreases significantly ( ). Since time is a key variable for bubble separation ( Insufficient time means that microbubbles are carried into the lower liquid phase before they can reach the gas-liquid interface. The bubble removal rate drops sharply to below 60%.

[0125] Then, based on the above comparative experiments, it can be seen that:

[0126] When the slope At this time, the fluid is mainly dominated by tangential inertial force, which can maintain a long-path spiral flow, and the time and space utilization of gas-liquid separation is the highest.

[0127] When the slope At this point, the component of gravity along the inclined plane begins to dominate the flow field, and the fluid tends to slide down quickly rather than rotate, resulting in insufficient effective centrifugal separation time.

[0128] Therefore, 5° to 15° was determined as the critical parameter range that balances gravity-flow drainage and efficient separation.

[0129] Circumferential span value ( This value depends on the range of angles at which the guide vane extends along the circumference of the inner wall of the housing 110. It is preset according to the requirements of preventing airflow short-circuiting and ensuring the length of the separation path, for example, 270 degrees (i.e., Spend).

[0130] The method for presetting the circumferential span value (e.g., 270 degrees) is not arbitrary, but is based on the following:

[0131] To prevent airflow short-circuiting: the gas after gas-liquid separation needs to rise. If the guide vanes rotate more than 360 degrees (i.e., overlapping head-to-tail), the bubbles precipitated in the lower layer will be blocked by the upper guide vanes during their ascent, and will accumulate below the vanes to form large bubbles, disrupting the flow field. The default is less than 360 degrees (e.g., 270 degrees), leaving a 90-degree fan-shaped notch in the planar projection as a vertical channel for the rising gas phase.

[0132] Ensuring a stable separation path: The rotation angle must be large enough to establish a stable centrifugal force field. The fluid typically needs to rotate more than half a turn (180 degrees) to stabilize the velocity distribution. 270 degrees provides approximately 3 / 4 of a turn, representing a balance between separation efficiency and gas flow path.

[0133] 110 inner diameter of the shell ( ): Obtain the inner diameter value of the designed shell 110.

[0134] Secondly, the total vertical drop of the arc-shaped guide vane is calculated.

[0135] The calculation is based on the principle of spiral geometry. The spiral-shaped guide vane is unfolded along the inner wall of the shell 110 into a planar right-angled triangle, where one leg is the length of the corresponding arc and the other leg is the vertical drop. The specific calculation formula is as follows:

[0136] .

[0137] Among them, the arc length .

[0138] By substituting the preset parameters into the above formula, the total vertical drop of the arc-shaped guide vane from the inlet to the outlet can be accurately calculated. ).

[0139] in, This is based on the fundamental mathematical formula of the spiral development property of a cylinder in Euclidean geometry, belonging to well-known mathematical principles. The geometric principle is that when a cylinder is unfolded along its generatrix into a plane, the spiral on the cylinder unfolds into the hypotenuse of a right triangle. The base of the triangle equals the length of the arc. (i.e., horizontal projection distance). The included angle of the triangle = spiral slope. The opposite side (height) of a triangle equals the vertical drop. In a right triangle, Rearranging the terms yields: .

[0140] Next, the swirl separation region 112 is defined.

[0141] After calculating the total drop value ( After that, considering the installation process requirements, a small amount of structural clearance space (e.g., 50-100mm each) is usually reserved above (inlet 115 area) and below (between the end of the guide plate and the liquid surface) the total drop value. The sum of the total drop value and these necessary structural clearance spaces is defined as the longitudinal height of the swirling separation area 112 in the middle layer of the shell 110.

[0142] Therefore, by following the above steps, the vertical dimensions of each functional area inside the shell 110 can be accurately determined during the design phase, ensuring that the physical structure meets the hydraulic performance requirements.

[0143] When performing step S200 to determine the key structural parameters of the annular flow channel, the specific parameter acquisition, calculation basis, and configuration implementation methods are as follows:

[0144] First, regarding the method for obtaining the rated drainage flow rate Q of the ultrafiltration unit, the rated drainage flow rate Q is the source parameter for this system design, and its acquisition method mainly relies on the equipment's technical documentation. Those skilled in the art should consult the "Product Technical Specifications," "Equipment Nameplate," or "Operation Manual" provided by the upstream ultrafiltration (UF) unit manufacturer. Specifically, this flow rate Q typically refers to the instantaneous maximum design flow rate of the ultrafiltration unit under backwashing or air scouring conditions. If the technical documents only provide the design flux of a single membrane module and the number of membrane modules, then it needs to be obtained through calculation: After obtaining the value, it is usually multiplied by an engineering fluctuation coefficient (such as 1.1) to cover the flow pulsation of the pumping system, so as to obtain the final rated drainage flow Q used for calculation.

[0145] Secondly, the determination method of the preset liquid film thickness δ is not randomly selected, but an empirical design value determined based on the "thin film fluid mass transfer theory". The determination basis is that in the gas-liquid separation process, the thinner the liquid film, the shorter the path of the micro-bubbles in the fluid to the gas-liquid interface, and the higher the separation efficiency; but if the liquid film is too thin, it is easy to break under the influence of surface tension to form a dry area, resulting in that the fluid cannot cover the entire flow guide plate. For semiconductor wastewater (usually with a viscosity close to that of water at room temperature), in order to balance the high mass transfer efficiency and the stability of continuous flow, the preset liquid film thickness δ is usually selected in the interval of 3mm to 8mm. In the preferred configuration of the present embodiment, in order to cope with the impact of backwashing large flow, it is recommended to set δ to 5mm as the standard calculation reference.

[0146] In the thin film fluid mass transfer theory mentioned in the present embodiment, it is essentially an engineering expression of applying the classical double film theory to the falling film flow hydraulic model. The double film theory believes that there are stable gas film and liquid film between the gas-liquid two phases, and the mass transfer resistance is mainly concentrated in these two films. In the present system, the core of the present application is to use the centrifugal force generated by the cyclone to stretch the thick water layer into a thin liquid film. According to the double film theory, the mass transfer rate By controlling the fluid into a thin film, on the one hand, the gas-liquid contact specific surface area is greatly increased, and on the other hand, the surface ripples generated by the thin film flow accelerate the renewal of the liquid film surface, and improve the liquid-side mass transfer coefficient kL. Therefore, the design basis of the present embodiment is based on the mass transfer enhancement mechanism of the double film theory under the thin liquid film working condition.

[0147] As for the specific determination method of the preset liquid film thickness δ (3mm-8mm), it is not randomly selected between 3mm and 8mm, but determined based on the balance relationship between the minimum wetting rate and the effective mass transfer depth. The specific determination steps are as follows:

[0148] Step one: determine the lower limit value (prevent dry area formation). According to the minimum wetting rate principle. In order to prevent the liquid film from breaking under the action of surface tension to form a dry area, resulting in local failure of the flow guide plate, the minimum thickness needs to be calculated. For the combination of stainless steel surface and water, the empirical formula shows that in order to ensure continuous coverage, the Reynolds number Re needs to be greater than a certain critical value. In engineering, the minimum empirical thickness to ensure that the fluid can completely cover the surface is usually about 2mm. Considering the possible slight unevenness of the flow guide plate surface and the machining tolerance, the engineering lower limit is set to 3mm.

[0149] The minimum wetting rate is a core physical concept in the falling film flow heat and mass transfer process. It refers to the minimum unit width mass flow rate (or volume flow rate) required to maintain continuous and complete liquid film flow on the solid wall surface. When the flow rate of the liquid is lower than the critical value, the originally continuous liquid film will break due to the contraction of the liquid surface tension being greater than the spreading of the gravity or shear force, and will shrink into several independent streams or droplets, resulting in bare dry areas on the solid wall surface. If the flow rate is lower than the minimum wetting rate on the arc-shaped guide plate of the present application, the guide plate will not be completely covered by the water flow, resulting in a significant reduction in the gas-liquid separation area, and the un-wetted area is prone to accumulate dirt. Therefore, determining the minimum wetting rate is the theoretical basis for setting the lower limit of the preset liquid film thickness.

[0150] The source and content of the empirical formula for the wetting of the stainless steel surface (Reynolds number criterion) The empirical formula mentioned here is the liquid film stability criterion commonly used in the design of falling film evaporators or packed towers in the field of chemical engineering. The criterion is usually based on the correlation between Reynolds number (Re) and wetting performance. Such formulas and data are widely recorded in Perry's Chemical Engineer's Handbook and related falling film flow monographs. The formula content is as follows:

[0151] The Reynolds number of the liquid film flow is defined as: .

[0152] Wherein: (Gamma) is the mass flow rate per unit wetting perimeter ( ), the calculation formula is (in the simplified model of the present embodiment);

[0153] is the dynamic viscosity of the liquid ( );

[0154] is the density of the liquid.

[0155] Empirical criterion: for the flow of normal temperature water on the surface of industrial stainless steel (determined by a certain contact angle), engineering experimental data show that when , the liquid film is in laminar flow and is extremely prone to breakage, and cannot maintain full wetting; when , the liquid film is in a transition state, and dry areas may appear; when , the liquid film enters a turbulent or wavy laminar state, and the inertial force is sufficient to overcome the surface tension, which can ensure the complete wetting of the surface.

[0156] According to the above known experience, set as a safety threshold. Substituting into the Reynolds number formula, the corresponding minimum mass flow rate is back calculated, and the flow rate The minimum liquid film thickness required to ensure complete wetting (i.e. the aforementioned engineering lower limit of about 2-3 mm) can be calculated.

[0157] Step two: Determine the upper limit value (to ensure mass transfer efficiency). According to the penetration theory or surface renewal theory, the effective depth of dissolved gas diffusion from the liquid phase bulk to the liquid phase interface is limited. If the liquid film is too thick (e.g. more than 10 mm), the deep layer fluid (bottom layer fluid) close to the guide plate wall is subjected to minimal surface disturbance, forming a mass transfer dead zone, and it is difficult for dissolved oxygen to diffuse to the surface for release. Fluid mechanics experiments and simulations show that, under the working condition of cyclone, 8 mm is the effective upper limit of thickness that can maintain full layer turbulence and ensure that the deep layer fluid can be entrained to the surface.

[0158] Step three: Comprehensive determination Based on the above, 3 mm (covering the safety lower limit) to 8 mm (mass transfer effective upper limit) are selected as the preferred interval of the preset liquid film thickness δ. In the calculation of step S200, in order to deal with the flow fluctuation (the film thickness will temporarily increase when the flow increases) caused by ultrafiltration backwash, the middle value (such as 5 mm) is usually taken as the reference calculation value.

[0159] Then, the formula is a general physical formula derived based on the classical continuity equation in fluid mechanics, which belongs to the known physical principles. The derivation process is as follows: Where the cross-sectional area of the annular flow passage is The theoretical width after transformation is After introducing the correction coefficient k1 , it becomes an engineering formula: .

[0160] The correction coefficient k1 is to compensate for the boundary layer effect and frictional resistance of the fluid in the flow passage. Because the flow velocity of the fluid close to the inner wall of the guide plate and the shell 110 is lower than the average flow velocity, the actual effective through-flow capacity is less than the theoretical value. The specific determination method is to determine according to the surface roughness of the guide plate material. For a polished stainless steel surface, k1 is usually 1.05 to 1.1; for an unpolished industrial steel plate or plastic surface, k1 is usually 1.1 to 1.2. Those skilled in the art can refer to the roughness coefficient table in the "Hydraulic Calculation Manual" for fine tuning.

[0161] The tangential velocity V L and the determination method of its minimum critical velocity are as follows:

[0162] In the calculation of the minimum critical velocity, in order to ensure that the fluid can flow close to the inner wall of the shell 110 without falling when rotating, it must satisfy the condition that the centrifugal force is greater than the gravity. According to the physical formula , the minimum critical velocity can be obtained, where g is the gravitational acceleration, R is the radius of the shell 110.

[0163] The determination of the preset tangential flow rate : In order to obtain a high-efficiency gas-liquid separation effect, simple wall adhesion is not enough, and a strong centrifugal field must be generated (usually requiring a centrifugal acceleration several times the gravitational acceleration). Therefore, the preset tangential flow rate is usually set to 2 to 4 times the minimum critical speed. Example: if the radius R of the shell 110 is , then . In design, can be set to to .

[0164] Here, the tangential flow rate is set to 2 to 4 times the minimum critical speed based on the calculation results of the separation factor. The specific determination method is as follows:

[0165] Step one: Calculate the minimum critical speed . As mentioned earlier, the physical condition under which the fluid does not fall is that the centrifugal force is at least equal to the gravitational force (i.e., the separation factor ). The formula is: At this speed, the fluid is only barely adhering to the wall, and the buoyancy (centripetal force) experienced by the gas bubbles is comparable to the gravitational force, resulting in extremely low separation efficiency.

[0166] Step two: Introduce the separation factor for target setting. The gas-liquid separation efficiency depends on the upward velocity of the gas bubbles in the liquid, and the upward velocity is proportional to the acceleration. In a cyclone field, the centrifugal acceleration . Define the separation factor . When , (the effect is the same as gravitational settling, with no enhancement effect). In order to achieve enhanced degassing, the industry usually requires a centrifugal field strength of at least 4 to 16 times that of the gravitational field.

[0167] Here, the separation factor is a dimensionless parameter used to measure the strength of the separation field in centrifugal separation technology (cyclone, centrifuge). In a gravitational settling tank, the driving force for the upward movement of gas bubbles or the downward movement of particles is the gravitational acceleration . In a cyclone separator, the driving force is the centrifugal acceleration generated by rotation . In order to intuitively quantify how many times the separation capacity of the cyclone has been improved relative to the ordinary gravitational settling tank, the ratio of these two accelerations is defined in engineering as the separation factor . According to Newtonian mechanics, the centrifugal acceleration of a fluid in circular motion is . Here,​ is the tangential linear velocity; is the radius of rotation. Substituting into the ratio formula, we get:

[0168] When , it means that the centrifugal force generated by rotation is equivalent to gravity. At this time, the fluid is in equilibrium on the vertical wall surface, and the bubble separation speed is the same as in the static water tank, without strengthening effect. When , it means that the centripetal buoyancy (force for separation) of the bubble is 4 times the natural buoyancy it receives in static water. This means that the upward separation speed of the bubble is theoretically increased by 4 times, or for the same size of the bubble, the residence time required for separation is shortened to 1 / 4 of the original. Therefore, the present application sets the tangential flow rate to 2 to 4 times the critical speed (i.e. the speed corresponding to ), which is essentially to set the separation factor to to , i.e. to . This is an engineering-verified golden interval that can significantly improve degassing efficiency and has controllable energy consumption.

[0169] Step three: reverse the multiple relationship. If the separation factor is required (i.e. 4 times the gravity separation effect), then: . If the separation factor is required (i.e. 16 times the gravity separation effect, which belongs to high-efficiency centrifugation), then: .

[0170] Step four: determine the final range. Therefore, set the tangential flow rate to 2 to 4 times , which essentially ensures that the centrifugal separation strength generated by the system reaches 4G to 16G. Below 2 times (<4G), the separation efficiency is not significantly improved, and it is difficult to remove small bubbles. Above 4 times (>16G), the fluid resistance increases sharply, the energy consumption is too large, and it may cause severe shear emulsification, which is actually not conducive to bubble aggregation. Therefore, 2 times to 4 times is the best engineering flow rate interval derived based on the separation factor .

[0171] Finally, after calculating the width W value of the annular flow channel, the arc-shaped guide plate is configured in place through physical and mechanical installation means, and the specific operation is as follows:

[0172] Positioning reference, taking the cylindrical inner wall surface of the shell 110 as the installation reference surface.

[0173] Radial size control, the curvature radius of the arc-shaped guide plate should be designed as That is, the outer surface radius of the deflector is equal to the inner radius of the shell 110 minus the calculated width W.

[0174] The distance between the inner wall of the shell 110 and the curved deflector is kept constant by welding or bolting distance supports or L-shaped mounting brackets with a length equal to the width W. During installation, the perpendicular distance between the deflector and the inner wall of the shell 110 at each point on the circumference is checked with a caliper or template to ensure that the distance remains constant at the calculated width W, thereby physically constructing an accurate annular flow channel.

[0175] The reason for introducing the Weber number in step S300 is that the impact of the protective gas on the liquid film in the gas-liquid separation device 1 is a double-edged sword. If the impact is too small, the gas flow will only slide over the liquid surface, unable to break the laminar boundary layer on the surface of the liquid film, and the dissolved oxygen in the deep layer cannot be replaced, resulting in low degassing efficiency. If the impact is too large, the gas flow will tear the liquid film, causing tiny liquid droplets to splash (entrainment of mist), which, if carried into the exhaust port 114 with the gas, will cause pollution, or splash into the gas phase region 111, causing turbulence. Therefore, it is necessary to find a balance point that can generate strong surface wave disturbance without causing splashing. In fluid mechanics, the Weber number is a dimensionless number that measures the relative size of the inertial force (destructive force) and the "surface tension (restoring force)", so it is introduced as the core criterion of this step.

[0176] Formula is based on the general definition formula of the classical Weber number in fluid mechanics The formula is adapted for the engineering application scenario. In the general formula, is the characteristic length. In the falling film flow model of the present application, the key scale for the liquid film to remain stable is the liquid film thickness, so the liquid film thickness determined in the previous step is selected as the characteristic length . The formula conforms to the basic principles of fluid mechanics. The specific method for obtaining each parameter in the formula is as follows:

[0177] (Density of protective gas (external gas source)): According to the type of inert gas selected (usually nitrogen) and the operating temperature and pressure of the gas phase region 111, refer to the "Gas Property Table" to obtain. Example: At normal temperature and pressure, the density of nitrogen is .

[0178] (Surface tension of wastewater): According to the temperature and main components of the wastewater, refer to the Physical Chemistry Manual. For semiconductor wastewater, if there is no large amount of surfactant, the surface tension value of water at normal temperature is usually taken as an approximation. Example: At 20°C, the surface tension of water is .

[0179] (characteristic length): directly using the preset liquid film thickness value (for example, 0.005 m) set and calculated in step S200.

[0180] (gas-liquid relative velocity): refers to the difference between the gas flow impact velocity vector and the liquid flow surface velocity vector. Since the gas flow velocity is usually much greater than the liquid flow velocity in the design , and the relative velocity is the largest in the preferred embodiment of the method using countercurrent injection. The calculation is simplified to the initial design calculation, and for the simplified model, it is usually approximated (that is, the gas flow impact velocity).

[0181] The effective disturbance range in step S300 is derived from the Kelvin-Helmholtz instability theory and the flow pattern transition experimental data of gas-liquid two-phase flow.

[0182] Lower limit (corrugation generation critical value): when the dynamic pressure head generated by the gas flow exceeds the constraint of the surface tension on the liquid surface, the smooth liquid surface begins to produce capillary waves. According to the fluid mechanics literature (such as "Multiphase Fluid Mechanics"), for the gas-blowing liquid film model, this critical Weber number is usually between 2.0 and 3.0. Below this value, the liquid surface is as smooth as a mirror, with no surface renewal effect.

[0183] Upper limit (splash generation critical value): when the inertial force of the gas flow is too large, it overcomes the viscous force and surface tension of the fluid, causing the liquid wave to break and form droplets. According to engineering experience and experiments, for thin liquid films, the critical Weber number for splashing is usually between 10.0 and 12.0.

[0184] Designers can define the preset effective disturbance range of the system as based on the above theoretical range and in combination with the safety factor. Among them, 2 is the lower limit to ensure wave generation; and 10 is the upper limit to prevent splashing.

[0185] Among them, the source and experimental steps of the flow pattern transition experimental data of gas-liquid two-phase flow are as follows:

[0186] The flow pattern transition experimental data here refers to the special verification experimental data conducted by the inventors of the present application based on the classical flow pattern transition theory for the specific tangential cyclone and countercurrent blowing structure of the present application.

[0187] In order to meet the requirement of full disclosure, the specific steps of the experiment are as follows:

[0188] Build the aforementioned transparent acrylic gas-liquid separation device 1 model. Set the high-speed camera (frame rate > 1000 fps) to focus on the liquid film surface in the middle of the guide plate.

[0189] The experimental procedure involves first establishing a steady-state liquid film, then turning on the inlet pump and adjusting the flow rate to create a thick film on the guide plate. A stable liquid film was formed; then, the gas velocity was incrementally scanned, the inert gas source was turned on, and the gas flow rate of nozzle 1411 was increased very slowly from zero, controlled by a mass flow meter. Following flow pattern observations, during Phase 1 (the mirror zone), at low gas velocities, the liquid surface remained smooth and mirror-like, with no visible ripples; during Phase B (the wave-inducing zone), when the gas velocity reached a certain point... At this point, the high-speed camera captured the appearance of fine, fish-scale-like capillary waves on the liquid surface, with the ripples propagating downstream. The physical parameters at this time were recorded. In stage C (the disturbance zone), as the gas velocity continued to increase, the wave amplitude increased, forming rolling waves, and the liquid surface underwent violent renewal. In stage D (the splash zone), when the gas velocity reached a certain point... At that time, it was observed that the wave crest was clipped by the airflow, generating tiny droplets that detached from the liquid surface and entered the gas phase (i.e., the starting point of mist entrainment). Finally, data processing was performed to determine the critical point. and By substituting the Weber number formula into the data, experimental data on flow pattern conversion for this device were obtained.

[0190] The air-blown liquid film model is a simplified physical model in fluid mechanics used to study shear-driven liquid film flow. Specifically, it is defined as: assuming a layer with a certain thickness... A liquid adheres to a solid wall and flows, while a high-speed gas flows tangentially (or counter-tangentially) across the liquid surface. This model primarily studies how the shear stress at the gas-liquid interface overcomes surface tension, thereby altering the liquid surface morphology. The annular gas curtain blowing swirling liquid film in this invention is a typical engineering application of this model.

[0191] Critical Weber number Typically, it's between 2.0 and 3.0, based on the Kelvin-Helmholtz instability theory. For ripples to form on the liquid surface, the airflow applies aerodynamic lift (compared to the pressure exerted on the crests of the ripples) to the surface. (Proportional to) the surface tension (which must be overcome in an attempt to smooth out the ripples) (Proportional). Theoretically, when the ratio of inertial force to surface tension (i.e., the Weber number) exceeds 1, the liquid surface becomes unstable. However, in engineering practice, due to the viscous damping effect of the liquid, greater energy is required to maintain a stable, visible propagating wave. Numerous fluid mechanics documents indicate that for a water-air system, when... When the Weber number exceeds the interval of 2.0 to 3.0, the liquid surface will truly enter the surface renewal ripple zone from the hydraulically smooth zone. Below this value, the liquid surface is too calm, and dissolved oxygen cannot effectively diffuse to the surface, which does not meet the purpose of mass transfer enhancement of the present application. Among them, the setting of this critical interval (2.0 to 3.0) refers to the classical theory of gas-liquid interface ripple generation in fluid mechanics (such as the interface wave generation criterion proposed by Cohen & Hanratty). According to the theory and the verification experiment of the present application, when the Weber number of gas-liquid relative motion is lower than 2.0, the liquid surface is mainly controlled by surface tension, showing a hydraulically smooth state, and cannot produce effective surface renewal; when the Weber number exceeds the critical value interval (2.0-3.0), the gas flow shear force begins to dominate, and the liquid surface produces stable capillary waves, thereby significantly improving the mass transfer efficiency.

[0192] The critical Weber number for splashing Usually between 10.0 and 12.0, is derived from the famous paper "Inception criteria for droplet entrainment in two-phase concurrent film flow" by Ishii, M. and Grolmes, M. A. in 1975. They studied the critical condition of liquid film droplet entrainment (Entrainment) under gas flow shear at different Reynolds numbers through a large number of experiments. They proposed that when the shear force exerted by the gas flow on the wave crest is large enough to overcome the binding of surface tension, the wave crest will be blown off to form droplets.

[0193] The critical Weber number for splashing Usually between 10.0 and 12.0 is based on the Saffman critical Weber number, which is a famous theory in fluid mechanics. Hinze pointed out that for droplets or liquid columns in gas flow, the critical Weber number for breakage is about 12 (for the shear breakage mode, the value usually fluctuates between 10-12). In the application in this system: when , the inertial force of the gas flow is more than 10 times the surface tension. At this time, the gas flow is no longer just pushing the liquid surface to fluctuate, but like a knife directly cutting the protrusions (wave crests) on the liquid film surface into micron-sized droplets. These splashing droplets contain salt and pollutants, which will cause environmental pollution once they are entrained into the gas phase area 111 and discharged with the exhaust gas; or form aerosols in the gas phase space, affecting the sensitivity of the pressure regulating assembly.

[0194] Therefore, in order to absolutely safely prevent splashing, the present configuration method strictly sets the upper limit of the effective disturbance interval to 10.0 to 12.0 as an insurmountable red line.

[0195] The selection of the Weber number We value in step S300 and the backstepping method of the optimal impact velocity are as follows:

[0196] In order to ensure the robustness of the system operation, the geometric center value or the weighted average value of the effective disturbance interval is usually selected as the target We value. It is recommended to select Because this value can not only ensure the generation of strong fish scale corrugation (enhanced mass transfer), but also have sufficient safety margin from the splashing threshold (10) to prevent accidental splashing caused by gas source pressure fluctuation.

[0197] Optimal gas flow impact velocity Backstepping method: after determining the target (e.g. 6), the formula in step S300 is used for mathematical transformation to solve.

[0198] Original formula:

[0199] Transformed formula:

[0200] Final determination: substitute the known parameters into the above root formula to calculate . In view of , the calculation result is the required optimal gas flow impact velocity .

[0201] Calculation example: let , , , .

[0202]

[0203] That is, the designer should control the velocity of the gas flow reaching the liquid surface at about 8.7 m / s.

[0204] In step S400, the establishment of the vertical distance mapping relationship and the parameter acquisition method are as follows:

[0205] In this step, the core of establishing the mapping relationship is to convert the three-dimensional spiral space structure into a two-dimensional function relationship. The specific establishment method is:

[0206] First, establish a geometric model: take the center axis of the shell 110 of the gas-liquid separation device 1 as the Z axis, and take the projection of the water inlet point of the tangential inlet assembly 120 on the horizontal plane as the polar coordinate zero point (i.e. angle ), to establish a cylindrical coordinate system. Since the gas distributor 141 (annular spray pipe) is usually installed horizontally, and the lower arc-shaped guide plate is in a spiral downward, the vertical distance between the two is the angle The function.

[0207] Secondly, the derivation of the function formula is based on the geometric properties of the spiral and the perpendicular distance mapping relationship. The calculation formula is:

[0208]

[0209] When expanded, it appears as follows:

[0210]

[0211] in, The initial vertical distance is the physical vertical distance from the bottom surface of the annular spray pipe to the upper surface of the starting end (inlet end) of the arc-shaped guide plate. It can be directly measured from the mechanical assembly drawings (CAD drawings) of the gas-liquid separation device 1, or measured by a laser rangefinder after the equipment is assembled. (Average radius of the annular flow channel) is the distance from the centerline of the annular flow channel width to the central axis of the housing 110, which can be determined based on the annular flow channel width in step S200. and the inner radius of the shell 110 Calculated . (Radian angle) is the circumferential angle (in radians) of the current position of nozzle 1411 relative to the starting point. It can be determined according to the arrangement design of nozzles 1411 on the annular spray pipe. For example, if the first... One nozzle 1411 is located at Location, then . (Spiral flow channel slope) can be directly referenced from the preset spiral flow channel slope value of the arc-shaped guide plate determined in step S100 (e.g.) ).

[0212] Regarding aperture The specific methods for sequentially increasing the impact velocity and maintaining the impact speed are as follows:

[0213] Physical principle (jet attenuation model): In order to compensate for the distance To compensate for the decrease in gas velocity caused by the increase in aperture size, this method uses the Abramovich formula from fluid mechanics for aperture compensation. The formula is as follows:

[0214]

[0215] in, The jet attenuation constant (for a circular nozzle 1411, the empirical value is usually taken as...) ).

[0216] Among them, the jet attenuation constant It is a dimensionless parameter determined based on GN Abramovich's theory of free turbulent jets. Its physical meaning is related to the length of the jet potential core region.

[0217] Jet attenuation constant (Also often marked as in different documents) or This theory originates from the "free turbulent jet theory" in fluid mechanics. The most authoritative source of this theory is the classic textbook "Theory of Turbulent Jet" by the Soviet fluid mechanician GN Abramovich. According to this theory, when gas is injected from a circular nozzle 1411 into a static (or low-speed) environment, the decay of its axial velocity follows the law of conservation of momentum. The jet structure is divided into an initial section (potential flow core region) and a main section (fully developed region).

[0218] constant Essentially, it reflects the length of the potential flow core region of the jet. Experiments show that the length of the potential flow core region of a circular jet... Approximately 1411mm diameter nozzle 5 to 6 times that.

[0219] Attenuation formula: In the main body segment (i.e. ), axis velocity With distance They are inversely proportional, as expressed by the formula:

[0220]

[0221] Among them, the engineering-recognized constants The value range is 5.0 to 6.0 (a smaller value is usually used for rim nozzle 1411, and a larger value is used for streamlined nozzles).

[0222] Although there are generally accepted ranges, in order to obtain precise constants for the specific nozzle 1411 selected for this device (such as a drilled hole, a tapered nozzle, etc.), Alternatively, calibration can be performed according to the following standard fluid mechanics experimental procedures:

[0223] Step 1: Set up the test platform, fix the gas distributor 141 (or a single nozzle of the same specification) selected in this embodiment onto the test bracket, connect the gas source, and adjust the outlet flow rate to the design operating conditions. (For example ).

[0224] Step 2: Centerline velocity measurement. Using a Pitot tube in conjunction with a micromanometer, or a hot-wire anemometer, measure the flow velocity at regular intervals (e.g., every 10 mm) along the extension of the center axis of nozzle 1411. The coverage distance of the measurement range is... to interval (i.e. the actual vertical distance range in the present application).

[0225] Step three: data fitting, record multiple sets of data points. Transform the formula to . Plot with as the horizontal coordinate and as the vertical coordinate. In theory, this should be a straight line through the origin, and the slope of this line is . By least squares linear fitting, the slope of the line can be calculated, and then the accurate constant for the specific nozzle 1411 structure is calculated.

[0226] Step four: engineering simplification, if in the actual engineering does not have experimental conditions, for the standard cylindrical drill hole (aspect ratio ), can directly select as the basis for calculation; for the contraction type nozzle, can directly select . This deviation is usually within the 5% error range allowed in engineering, which can meet the requirements of the present configuration method.

[0227] For the standard circular nozzle 1411 used in the present embodiment, according to the well-known knowledge and experimental calibration of fluid mechanics, the value range of the constant is determined to be 5.0 to 6.0. In the preferred calculation of the present method, take to configure the hole diameter.

[0228] The specific configuration steps are as follows:

[0229] Step one: determine the initial velocity of the nozzle 1411 outlet According to the gas supply pressure and the flow coefficient of the nozzle 1411, set a uniform nozzle 1411 outlet flow rate . The speed is usually determined by the set value of the pressure reducing valve of the gas supply system.

[0230] Step two: extract the target impact speed Directly quote the "optimal gas flow impact speed " obtained by backstepping in step S300 as the constant target value.

[0231] Step three: calculate the required hole diameter at each position For the th nozzle 1411 with an angle of on the circumference, substitute its corresponding vertical distance into the transformed jet formula:

[0232]

[0233] From the equation, it can be seen that the required aperture is directly proportional to the perpendicular distance .

[0234] Step 4: Engineering the rounding calculation of the aperture may be a non-standard value. In actual processing, the standard drill bit diameter closest to the calculated value (for example, the calculated value is , and the drill bit with a diameter of is selected for processing, so as to realize the physical configuration of increasing the aperture with the increase of the distance.

[0235] In the present embodiment, the fluid (ultrafiltration water) is affected by gravity and centrifugal force on the arc-shaped guide plate, and flows along the spiral path from top to bottom. Therefore, for the liquid surface of a certain point, the incoming flow direction refers to the upstream direction of the fluid flow (i.e. the opposite direction of the spiral tangent).

[0236] The reason for being configured to be inclined to the incoming flow direction (counter-flow injection) is as follows:

[0237] Maximize the relative velocity: gas-liquid mass transfer and surface shear depend on the relative velocity . If the flow is blown (co-flow): . If the flow is blown (counter-flow): . Obviously, counter-flow injection can superimpose the speed of both, resulting in the largest relative speed.

[0238] Strengthen the shear renewal: the gas flow of counter-flow injection scratches the liquid surface against the flow direction like a rake, which can produce stronger shear stress, thereby more effectively tearing the laminar boundary layer (mass transfer resistance layer) on the surface of the liquid film, forcing the deep liquid to surge to the surface. Experiments show that the surface renewal frequency of counter-flow injection is more than 30% higher than that of vertical or co-flow injection, thereby significantly improving the degassing efficiency.

[0239] The above described in the specification of the present application is only an example of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or use similar ways to replace, as long as it does not deviate from the content of the present application or exceed the scope defined by the present claims, which shall belong to the protection scope of the present application.

Claims

1. A wastewater treatment system for the semiconductor industry, characterized in that, It includes an ultrafiltration unit, a reverse osmosis unit, and a gas-liquid separation unit disposed between the two, wherein the gas-liquid separation unit includes: The housing defines an upper gas phase region, a middle cyclone separation region, and a lower liquid phase region. The outer side of the housing is provided with an exhaust port connected to the gas phase region, a liquid inlet connected to the cyclone separation region, and a liquid outlet connected to the liquid phase region. The liquid inlet is connected to the product water end of the ultrafiltration device, and the liquid outlet is connected to the inlet end of the reverse osmosis device. A tangential flow inlet assembly is disposed at the liquid inlet and configured to introduce fluid into the housing tangentially along the inner wall of the housing. A flow guiding assembly is disposed in the swirling separation region inside the housing. The flow guiding assembly is arranged on the extension path of the outlet of the tangential inlet assembly and is configured to guide the fluid to form a circumferentially rotating downward flow on the inner wall of the housing. A scavenging assembly includes a gas distributor extending into the gas phase region, the scavenging assembly being configured to access an external gas source and release protective gas into the gas phase region through the gas distributor; The liquid outlet assembly includes a pipe section and an anti-vortex component connected to one end of the pipe section. The other end of the pipe section is connected to the liquid outlet. The anti-vortex component is located inside the liquid phase region. The top of the anti-vortex component is closed and the side wall is provided with a flow hole. The anti-vortex component is configured to block the bubbles precipitated from the gas phase region and the liquid surface from entering the liquid outlet assembly. The flow guiding assembly includes an arc-shaped flow guiding plate fixed to the inner wall of the housing and extending along the circumferential direction of the housing. An annular flow channel is formed between the arc-shaped flow guiding plate and the inner wall of the housing, and the inlet end of the annular flow channel is directly opposite to the jet direction of the tangential flow inlet assembly. The lower edge of the arc-shaped guide plate extends below the horizontal plane of the centerline of the tangential inlet assembly and below the designed minimum liquid level of the liquid phase region. The gas distributor is constructed as an annular spray pipe, which is arranged along the inner periphery of the gas phase region. The annular spray pipe has a plurality of spray holes, the opening direction of which is inclined toward the inner wall of the housing, and each spray hole is configured to form an annular air curtain in the gas phase region. The gas-liquid separation device further includes an inert gas source connected to the scavenging component and a pressure regulating component connected to the exhaust port; the wastewater treatment system is configured to maintain the gas phase region at a positive pressure state through the pressure regulating component and to use the scavenging component to replace dissolved oxygen and bubbles released from the cyclone separation region and the liquid phase region.

2. The semiconductor industry wastewater treatment system according to claim 1, characterized in that, The extension line of the central axis of the nozzle passes through the central region of the width of the annular flow channel.

3. The semiconductor industry wastewater treatment system according to claim 1, characterized in that, The total flow area of ​​all the flow holes is set to be 3 to 5 times greater than the cross-sectional area of ​​the pipe segment.

4. The semiconductor industry wastewater treatment system according to claim 1, characterized in that, The top position of the anti-vortex component is configured to be at least 100 mm below the design minimum liquid level of the liquid phase region.

5. The semiconductor industry wastewater treatment system according to claim 1, characterized in that: The extension line of the central axis of the nozzle passes through the central region of the width of the annular flow channel; The top position of the anti-vortex component is configured to be at least 100 mm below the design minimum liquid level of the liquid phase region.

6. A configuration method for a semiconductor industry wastewater treatment system as described in claim 5, characterized in that: The reverse osmosis unit has a high-pressure pump; The configuration method includes the following steps: The high-pressure pump suction head parameters and preset safety margin values ​​of the reverse osmosis unit are obtained to determine the height value of the liquid phase region; the preset spiral channel slope value and circumferential span value of the arc-shaped guide plate are obtained to determine the total vertical drop value of the arc-shaped guide plate, and the area with the total vertical drop value is defined as the vortex separation region; the remaining space in the shell is defined as the gas phase region; Obtain the rated drainage flow rate Q of the ultrafiltration device, and set the preset liquid film thickness δ for the fluid flowing on the arc-shaped guide plate; according to the formula W=k1×Q / (V L ×δ) determines the width W of the annular flow channel, and configures the distance between the arc-shaped guide plate and the inner wall of the shell according to the width W; where k1 is a correction coefficient, V L The tangential flow velocity V is a preset tangential flow velocity. L It is set to be greater than the minimum critical velocity required for the fluid to maintain its adherent flow to the wall; Introducing the Weber number W e As a criterion for gas-liquid disturbance, the formula is W e =(ρ g ×V rel 2 ×δ) / σ;where ρ g The density of the protective gas from the external gas source, V rel Let W be the relative velocity between gas and liquid, and σ be the surface tension of the wastewater; select a Weber number W within a preset effective disturbance range. e The value is used to deduce the optimal airflow impact velocity V. gasimpact The lower limit of the effective disturbance range is the Weber number critical value at which ripples are generated on the liquid film surface, and the upper limit is the Weber number critical value at which droplets generate splashes. Establish a vertical distance mapping relationship between the positions of each nozzle of the gas distributor and the corresponding positions of the arc-shaped guide plate below. , The angular position along the circumferential direction; along the fluid flow direction, based on the vertical distance. As the diameter d of each nozzle increases, the calculated impact velocity of the airflow reaching the liquid film surface through each nozzle is maintained at the optimal airflow impact velocity V. gasimpact The central axis of each nozzle is configured to be inclined toward the direction of fluid flow, forming a counter-current injection angle.

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