Wastewater degradation system and method using radial microchannel discharge and cavitation synergy

Abstract

The present invention discloses a wastewater degradation system and method using radial microchannel discharge and cavitation synergistically, belonging to the technical field of organic wastewater treatment. The system comprises a wastewater tank, a microchannel discharge cavitation degradation device, an ozone generator, a venturi tube, and a collection tank. The venturi tube is respectively connected to the ozone generator, the wastewater tank, and the inlet of the wastewater to be degraded of the microchannel discharge cavitation degradation device. The present invention integrates dielectric barrier discharge technology with hydraulic cavitation technology. The dielectric barrier discharge generates a large amount of active substances in the inner and outer cavitation cavities, which, in conjunction with the rotation of the cavitation rotor, induces a strong cavitation effect around the rotor, thereby degrading organic wastewater. By providing a radial microchannel discharge device, the discharge area is increased, the amount of active substances such as ozone and hydroxyl radicals in the gas-liquid phase is increased, and the deactivation loss of active substances during transportation is reduced. By providing rotor cavitation teeth with opposite rotation directions, a circulating flow of the gas-liquid phase is triggered, thereby improving mass transfer efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic wastewater treatment, and in particular relates to a wastewater degradation system and method using radial microchannel discharge and coordinated cavitation. Background Art

[0002] With the increasing discharge of wastewater containing organic pollutants, hydrodynamic cavitation and dielectric barrier discharge technologies have attracted widespread attention in the field of organic wastewater treatment. Hydrodynamic cavitation uses a high-pressure drop to trigger the rapid formation and collapse of bubbles in water. This creates a high-temperature, high-pressure environment, which stimulates the decomposition of water molecules and produces highly energetic reactive particles such as highly oxidizing hydroxyl radicals (·OH), rapidly degrading organic pollutants. However, the number of reactive particles generated by hydrodynamic cavitation itself is limited, making it difficult to fully degrade high-concentration organic wastewater. Dielectric barrier discharge, on the other hand, applies a high voltage to break down air, creating a plasma environment rich in high-energy electrons, free radicals, and excited molecules. The plasma excites and ionizes water molecules, generating a large number of highly oxidizing reactive particles such as ozone (O3), hydrogen peroxide (H2O2), and hydroxyl radicals (·OH), overcoming the problem of hydrodynamic cavitation producing relatively few highly reactive particles. However, the reactive ions generated by dielectric barrier discharge have a short survival time in the liquid phase, limiting the degradation effect.

[0003] Therefore, the integration of hydrodynamic cavitation and dielectric barrier discharge technologies has resulted in a novel wastewater degradation system. The combination of the large amount of active substances generated by dielectric barrier discharge and the microbubbles produced by hydrodynamic cavitation not only improves the mass transfer efficiency between gas and liquid, but also promotes the generation of highly oxidizing free radicals, significantly increasing the degradation efficiency of organic wastewater.

[0004] Patent publication number CN 118479598 A, "A Microchannel Gas-Liquid Two-Phase Microdischarge Organic Wastewater Degradation Device," discloses a device for organic wastewater degradation using discharge within a microchannel. The device comprises a plunger pump, a microchannel chip, and a plasma power supply. By turning on the plunger pump, a gas-liquid two-phase flow flows from the microchannel chip into the discharge reaction chamber. The flow-focusing structure within the microfluidic chip generates microbubbles, which, in conjunction with cavitation and dielectric barrier discharge technology, degrade the organic wastewater. However, this device generates cavitation through an expanding and contracting structure, making it difficult to generate uniform and continuous microbubbles within the flow field. Compared to rotary cavitation devices, the device suffers from low cavitation efficiency and limited wastewater degradation capabilities.

[0005] The invention patent, "A Three-Stage Hydraulic Cavitation Treatment System for Organic Wastewater," with publication number CN 109824173 A, discloses a three-stage hydraulic cavitation treatment system for organic wastewater, comprising a precipitant tank, a coagulation tank, a sedimentation tank, a rotary hydraulic cavitator, a cavitation jet generator, and an ultrasonic cavitator. The rotary hydraulic cavitator generates cavitation through rotor shear force, the cavitation jet generator generates cavitation jets, and the ultrasonic cavitator uses ultrasonic waves to generate cavitation. The cavitated wastewater is ultimately oxidatively degraded in a Fenton reagent tank. Although this invention utilizes a combination of multiple cavitation technologies to treat organic wastewater, the active substances such as hydroxyl radicals generated by cavitation partially lose their activity during transportation, resulting in poor degradation and low energy utilization of the system.

[0006] Patent publication number CN 118005130 A, "A Device for Purifying Industrial Wastewater by Discharge at Normal Temperature and Pressure and Its Application Method," discloses a device and method for purifying industrial wastewater by discharge at normal temperature and pressure. The method comprises: placing an electrode tube in the center of an outer sleeve to form a discharge tube. An air compression tube is positioned within the airway; the discharge tube is placed within the wastewater to be purified. The compressed air tube continuously introduces high-pressure air into the airway, discharging the gas-liquid mixture under high-frequency and high-pressure conditions, ionizing the gas-liquid mixture into a plasma containing a large number of hydroxyl radicals. Although this method converts the surface discharge used in the prior art into a volumetric discharge, increasing the magnitude of the plasma discharge, the device can only ionize the air within the airway and cannot form a larger discharge area within a limited volume, limiting further improvements in degradation efficiency.

[0007] Patent application CN 119118415 A, "A System and Method for Hydrodynamic Cavitation and Plasma Degradation of Organic Wastewater," discloses a system and method for hydrodynamic cavitation and plasma degradation of organic wastewater. The system includes a liquid storage tank, an aeration device, and a plasma rotary cavitation reactor. Organic wastewater generates a large number of cavitation bubbles within the plasma rotary cavitation reactor. These bubbles are then passed through the jet cavitation channel to form a dielectric barrier plasma discharge within the plasma discharge chamber, generating ozone and hydroxyl radicals in the water. However, the device utilizes two conventional coaxial annular plates for surface discharge, and the cavitation and discharge processes can only occur on the outer wall of the rotor, resulting in low efficiency of the hydrodynamic cavitation and dielectric barrier plasma discharge.

[0008] In summary, the existing hydrodynamic cavitation synergistic discharge device for organic wastewater degradation still has the following problems in practical application:

[0009] First, the dielectric barrier discharge (DBD) area is small. The active species generated during the plasma discharge (such as hydroxyl radicals, high-energy electrons, and excited-state molecules) have a short lifetime in the liquid phase. As these active species are transported from the plasma region to the hydrodynamic cavitation zone, they are consumed in large quantities due to diffusion and reaction deactivation. This insufficient DBD area directly results in inefficient utilization of active species and poor degradation.

[0010] Second, hydrodynamic cavitation and low-temperature plasma discharge technologies cannot achieve synergistic degradation. The high-energy active substances generated in the plasma discharge area cannot promptly contact the microbubbles in the hydrodynamic cavitation zone, making it difficult for the active substances to fully exert their strong oxidizing effect, limiting further improvement in degradation efficiency. Summary of the Invention

[0011] In order to solve the above-mentioned problems in the prior art, the present application provides a wastewater degradation system and method with radial microchannel discharge and coordinated cavitation, which provides a new technical solution for achieving efficient degradation of organic wastewater.

[0012] The technical solution is as follows:

[0013] On the one hand, a wastewater degradation system with radial microchannel discharge and cavitation coordination is provided, comprising a waste liquid pool 1, a microchannel discharge cavitation degradation device 8, an ozone generator 5, a venturi tube 6, and a collection pool 9, wherein the ozone generator 5 is connected to the venturi tube 6, the venturi tube 6 is respectively connected to the waste liquid pool 1 and the microchannel discharge cavitation degradation device 8, the microchannel discharge cavitation degradation device 8 is connected to the collection pool 9, and the ozone generator 5 is respectively connected to the venturi tube 6 and the air pump 3;

[0014] The microchannel discharge cavitation degradation device 8 includes a driving mechanism 81, a conductive slip ring 82 connected to the driving mechanism 81, a cavitation stator 83, a cavitation rotor 85 located in the cavitation stator 83, a degradation device base 84 and a radial microchannel discharge device 86 fixed between the cavitation stator 83 and the degradation device base 84.

[0015] A further technical solution is that the wastewater degradation system is also provided with a peristaltic pump 7 and an overflow valve 4. The peristaltic pump 7 is used to transfer the wastewater in the waste liquid pool 1 through the venturi tube 6 to generate a gas-liquid two-phase flow containing ozone microbubbles, and send it to the microchannel discharge cavitation degradation device 8. The overflow valve 4 is respectively connected to the microchannel discharge cavitation degradation device 8 and the collection pool 9, and the two ends of the DC pump 2 are respectively connected to the waste liquid pool 1 and the venturi tube 6.

[0016] A further technical solution is that the drive mechanism 81 includes a rotor drive shaft 812, a motor support seat 813, a cavitation rotor motor 811 fixed on the motor support seat 813, a drive mechanism fixing seat 816 fixedly connected to the motor support seat 813, and a drive shaft upper bearing 814 and a drive shaft lower bearing 815 fixed on the drive mechanism fixing seat 816. The rotor drive shaft 812 is passed through the concentric holes formed by the conductive slip ring 82, the drive shaft upper bearing 814, and the drive shaft lower bearing 815 to form a tight fit. The rotor drive shaft 812 is connected to the cavitation rotor 85, and the rotor drive shaft 812 drives the cavitation rotor 85 to rotate.

[0017] A further technical solution is provided, wherein the radial microchannel discharge device 86 comprises a discharge device water inlet chamber 861, a plurality of micro jet holes 862 arranged on the inner wall of the discharge device water inlet chamber 861, an annular negative plate 863, a cylindrical discharge chamber 864, a threaded hole 865, a discharge rod 866, an annular positive plate 867 and an annular cavity 868. The micro jet holes 862 connect the discharge device water inlet chamber 861 and the cylindrical discharge chamber 864 and are radially distributed with the axis of the discharge device water inlet chamber 861 as the center; the cylindrical discharge chamber 864 is provided with a plurality of micro jet holes 862 arranged on the inner wall of the discharge device water inlet chamber 861, ... One end is connected to the annular negative plate 863, and the other end is connected to the inner cavitation chamber 834. The discharge rod 866 is fixed in the threaded hole 865. The annular positive plate 867 is positioned within the sealed cavity of the discharge rod 866 and tightly connected to the inner wall of the sealed cavity of the discharge rod 866. The annular negative plate 863 is positioned within the annular cavity 868 and tightly connected to the inner wall of the annular cavity 868. The annular cavity 868 is closely attached to the outer wall of the cylindrical discharge chamber 864, forming a small discharge gap between the outer wall of the discharge rod 866 and the inner wall of the cylindrical discharge chamber 864. In existing technical solutions, the dielectric barrier discharge method is generally a surface discharge between two coaxial or parallel plates. The radial structure transforms traditional surface discharge into a volume discharge. The radial structure also allows the dielectric barrier discharge area to extend all the way around the inner wall of the cavitation rotor 85, reducing the deactivation loss of active materials during transportation.

[0018] A further technical solution is that the outer wall surface of the cavitation rotor 85 is provided with a plurality of equidistant outer wall cavitation teeth 851 along the direction of the cylindrical outer wall generatrix, the rotation direction is clockwise, and a plurality of equidistant axial grooves are formed between two adjacent outer wall cavitation teeth 851, and the groove surfaces of all axial grooves are parallel to the outer wall generatrix; the inner wall surface of the cavitation rotor 85 is provided with a plurality of equidistant inner wall cavitation teeth 852 along the direction of the conical inner wall generatrix, the rotation direction is counterclockwise, and a plurality of equidistant grooves are formed between two adjacent inner wall cavitation teeth 852, and the groove surfaces of all grooves are parallel to the inner wall generatrix;

[0019] A narrow gap is formed between the outer wall cavitation teeth 851 and the inner wall of the outer cavitation cavity 833, and an expanded chamber is formed between the inter-tooth grooves and the inner wall of the outer cavitation cavity 833. The gap and chamber continuously alternate with the rotation of the cavitation rotor 85, generating periodic pressure fluctuations, thereby inducing a cavitation effect. A periodic alternation of wide and narrow flow channels is also formed between the inner wall cavitation teeth 852 and the outer wall of the radial microchannel discharge device 86, triggering a cavitation effect between the inner wall cavitation teeth 852 and the outer wall of the radial microchannel discharge device 86. In existing technical solutions, the cavitation rotor is generally a solid cylindrical gear-shaped structure. The cavitation rotor 85 with an inner cavitation cavity 834 has both discharge and cavitation functions around the outer wall cavitation teeth 851 and the inner wall cavitation teeth 852.

[0020] As a further technical solution, a number of equally spaced rotor cavitation channels 854 are radially opened between the outer wall and the inner wall of the cavitation rotor 85, and are radially distributed with the axis of the cavitation rotor 85 as the center; the rotor cavitation channels 854 connect the outer cavitation cavity 833 with the inner cavitation cavity 834.

[0021] A further technical solution is that the cavitation stator 83 includes a degradation wastewater outlet 831 and a stator annular negative electrode 832. The degradation wastewater outlet 831 is opened at the top of the outer cavitation cavity 833, passes through the upper end face of the cavitation stator 83, and is connected to the overflow valve 4 through a pipeline; the stator annular negative electrode 832 is arranged in the annular sealed cavity in the cavitation stator 83, and is tightly connected to the inner wall of the annular sealed cavity, forming a small discharge gap between the inner wall of the cavitation stator 83 and the outer wall of the cavitation rotor 85.

[0022] As a further technical solution, the relative dielectric constant of the material used for the cavitating stator 83 and the cavitating rotor 85 should be greater than 3.8.

[0023] A further technical solution is to introduce gas-liquid two-phase flow into the outer cavitation cavity 833 and the inner cavitation cavity 834, and the cavitation rotor 85 rotates stably at a certain speed. The torque output by the cavitation rotor motor 811 during operation is calculated based on the rotor's size parameters and operating parameters.

[0024] Assume that the viscosity of industrial wastewater is μ, in units of Pa·s, the rotational angular velocity of the cavitation rotor 85 is ω, in units of r / min, and the vertical distance from the rotor center axis to the rotor outer wall is r o , unit is m, the vertical distance from the rotor center axis to the inner wall of the stator is R, unit is m, the clearance of the cylinder wall is δ=Rr o , unit is m, the vertical distance from the upper surface to the lower surface of the rotor is L o , unit is m, according to Newton's law of internal friction, the friction force T on the outer wall of the rotor caused by the viscosity of the external cavitation cavity 833 industrial wastewater o , unit N, the friction force is calculated according to formula (1):

[0025]

[0026] Among them, τ is the shear stress on the outer wall of the rotor, A is the outer surface area of the rotor, and in order to balance the friction force T on the outer wall of the rotor o , the required torsional torque of the rotor is M o , unit N·m, the value of the torsional moment is calculated according to formula (2):

[0027]

[0028] Assume that the vertical distance from the rotor center axis to the rotor inner wall is r i , unit is m, the vertical distance from the rotor center axis to the outer wall of the radial microchannel discharge device (86) is r, unit is m, and the gap of the rotor inner conical wall is δ′=r i -r, unit is m, the vertical distance from the upper surface of the rotor cavity to the bottom of the rotor is L i , unit is m, according to formula (2), in order to balance the friction force on the inner wall of the rotor, the required torsional torque of the rotor is M i , unit N·m, the value of the torsional moment is calculated according to formula (3):

[0029]

[0030] If the space between the outer wall and the inner wall of the rotor is filled with industrial wastewater, the torque required for the rotor to rotate at an angular velocity ω is obtained according to equations (2) and (3): r , unit N·m, the value of the total torsional moment is calculated according to formula (4):

[0031]

[0032] After measuring the viscosity μ of the industrial wastewater and the rotational angular velocity ω of the cavitation rotor 85, the torque value required for the rotor to operate can be calculated according to Formula 4. By adjusting the torque of the cavitation rotor motor 811, the cavitation rotor 85 can operate with the minimum torsional torque, reducing the energy consumption of the cavitation rotor motor 811.

[0033] In another aspect, a wastewater degradation method using radial microchannel discharge and cavitation is provided, which utilizes the above-mentioned wastewater degradation system and comprises:

[0034] Step 1: The water tank 1 stores industrial organic wastewater, and the DC pump 2 and the air pump 3 are turned on to pump the industrial organic wastewater into the venturi tube 6. The ozone generated by the ozone generator 5 is simultaneously injected into the venturi tube 6 to fully mix the ozone with the industrial organic wastewater.

[0035] Step 2: The pressure inside the industrial organic wastewater is released at the throat of the venturi tube 6, generating a cavitation effect and generating a large number of microbubbles containing ozone. The industrial organic wastewater containing microbubbles is pumped into the microchannel discharge cavitation degradation device 8 through the peristaltic pump 7;

[0036] Step 3: The peristaltic pump 7 pumps the industrial organic wastewater containing microbubbles into the wastewater inlet 841. When the wastewater fills the entire cavity within the degradation device base 84, the wastewater enters the discharge device water inlet chamber 861 under the action of water pressure. The wastewater then passes through the micro-jet holes 862 and undergoes dielectric barrier discharge within the cylindrical discharge chamber 864, generating ozone and hydroxyl radicals.

[0037] Step 4: After the industrial organic wastewater enters the inner cavitation cavity 834, the cavitation rotor motor 811 is started, and the cavitation rotor 85 rotates, causing a strong cavitation effect around the inner wall cavitation teeth 852. The organic wastewater is sucked from the inner cavitation cavity 834 into the outer cavitation cavity 833 through the rotor cavitation channel 854, and a dielectric barrier discharge is formed between the outer wall of the cavitation rotor 85 and the inner wall of the cavitation stator 83. Combined with the cavitation effect generated by the outer wall cavitation teeth 851, the industrial organic wastewater is deeply degraded.

[0038] Step 5: After the degradation wastewater outlet (831) reaches a certain water pressure, the overflow valve (4) opens the passage between the degradation wastewater outlet (831) and the collection tank (9), and the purified industrial organic wastewater flows into the collection tank (9) for storage.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The present invention designs a radial microchannel discharge device. By providing radially distributed microjet holes on the inner wall of the water inlet chamber, wastewater containing a large number of microbubbles is introduced into the cylindrical discharge chamber, enabling the cylindrical discharge chamber to achieve volume discharge, effectively increasing the discharge area and the amount of active substances generated. The radial structure also allows the dielectric barrier discharge area to extend all the way to the inner wall of the cavitation rotor, reducing the inactivation loss of active substances during transportation and improving the efficiency of wastewater treatment.

[0041] (2) The present invention designs a multi-discharge cavitation process based on dielectric barrier discharge technology and hydrodynamic cavitation technology. The wastewater undergoes the first dielectric barrier discharge in the cylindrical discharge chamber, generating a low-temperature plasma rich in active substances in the organic wastewater. Combined with the local high temperature, high pressure and mechanical shock waves generated by the collapse of cavitation bubbles in the cavitation rotor cavity, the ozone molecules with a long lifespan and poor water solubility fully react with the organic wastewater. When the wastewater is squeezed into the outer cavitation cavity, a second dielectric barrier discharge is performed, combined with the cavitation effect of the outer wall of the cavitation rotor, to enhance the degradation process.

[0042] (3) The present invention optimizes the cavitation rotor structure. By providing an inner cavitation cavity, the inner and outer cavitation cavities simultaneously generate strong shear forces when the rotor rotates, thereby enhancing the cavitation effect and accelerating the formation and collapse of bubbles. The inner wall of the rotor is conical, which increases the contact area between the inner wall cavitation teeth and the wastewater, enhances the cavitation effect of the wastewater, and improves the gas-liquid mass transfer efficiency.

[0043] (4) The present invention designs a cyclic degradation process for wastewater. The rotor is provided with inner wall cavitation teeth and outer wall cavitation teeth with opposite rotation directions. The inner wall cavitation teeth form an attraction force on the gas and liquid phase around the inner wall of the rotor, attracting the gas and liquid phase to quickly pass through the jet holes to the periphery of the outer wall cavitation teeth. The outer wall cavitation teeth form a centrifugal force on the gas and liquid phase around the outer wall of the rotor, squeezing the gas and liquid phase to the vicinity of the inner wall cavitation teeth, forming a cyclic flow in the microchannel discharge cavitation degradation device, making the degradation process more thorough.

[0044] (5) This invention designs a method for calculating the minimum torsional torque during rotor operation. Based on torque balance analysis, the distribution of friction forces on the inner and outer walls of the rotor and the torque formula are calculated. Based on the relationship between industrial wastewater viscosity and rotational speed, the rotor motor outputs the lowest friction torque by adjusting the rotational speed. This achieves the goal of minimizing rotor energy consumption while meeting the process requirements for wastewater degradation and improving the economic efficiency of the degradation reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0046] Figure 1 A schematic diagram of a wastewater degradation system using radial microchannel discharge and cavitation synergy provided by an embodiment of the present invention;

[0047] Figure 2 A schematic structural diagram of a microchannel discharge cavitation degradation device provided in an embodiment of the present invention;

[0048] Figure 3 A schematic structural diagram of a tapered radial microchannel discharge device provided in an embodiment of the present invention;

[0049] Figure 4 for Figure 3 Schematic diagram of the structure of the discharge rod;

[0050] Figure 5 A schematic structural diagram of a cavitation rotor provided in an embodiment of the present invention;

[0051] Figure 6 A schematic structural diagram of a rotor annular positive electrode provided in an embodiment of the present invention;

[0052] Figure 7A schematic structural diagram of a cavitation stator provided in an embodiment of the present invention;

[0053] Figure 8 A schematic structural diagram of a microchannel discharge cavitation degradation device provided in an embodiment of the present invention;

[0054] Figure 9 A schematic structural diagram of a degradation device base provided in an embodiment of the present invention;

[0055] Figure 10 A flow diagram in a microchannel discharge cavitation degradation device provided by an embodiment of the present invention;

[0056] Figure 11 This is a flow chart of the wastewater degradation process provided by an embodiment of the present invention.

[0057] Explanation of reference numerals: 1. waste liquid tank; 2. DC pump; 3. air pump; 4. overflow valve; 5. ozone generator; 6. venturi tube; 7. peristaltic pump; 8. microchannel discharge cavitation degradation device; 81. driving mechanism; 811. cavitation rotor motor; 812. rotor driving shaft; 813. motor support seat; 814. upper bearing of driving shaft; 815. lower bearing of driving shaft; 816. driving mechanism fixing seat; 82. conductive slip ring; 83. cavitation stator; 831. degradation wastewater outlet; 832. stator annular negative electrode; 833. External cavitation cavity; 834, internal cavitation cavity; 84, degradation device base; 841, wastewater inlet; 85, cavitation rotor; 851, outer wall cavitation teeth; 852, inner wall cavitation teeth; 853, rotor annular positive pole; 854, rotor cavitation channel; 86, radial microchannel discharge device; 861, discharge device water inlet cavity; 862, micro jet hole; 863, annular negative plate; 864, cylindrical discharge chamber; 865, threaded hole; 866, discharge rod; 867, annular positive plate; 868, annular cavity; 9, collection tank. DETAILED DESCRIPTION

[0058] Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, like numbers in different figures represent like or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0059] The present invention integrates dielectric barrier discharge technology and hydraulic cavitation technology to design a wastewater degradation system with radial microchannel discharge and coordinated cavitation. Industrial organic wastewater generates a gas-liquid two-phase flow containing ozone microbubbles through a venturi tube 6 and an ozone generator 5. A peristaltic pump 7 pumps the gas-liquid two-phase flow into the wastewater inlet to be degraded of a microchannel discharge cavitation degradation device 8. Dielectric barrier discharge further electrically breaks down the bubbles in the inner and outer cavitation cavities to generate more ozone. The rotation of the cavitation rotor 85 triggers a strong cavitation effect around the cavitation rotor, fully dissolving the ozone bubbles in the liquid to generate hydroxyl radicals. The organic wastewater is degraded through strong mixed mass transfer. A radial microchannel discharge device 86 is provided to increase the discharge area, increase the amount of active substances such as ozone and hydroxyl radicals in the gas-liquid phase, and improve the degradation efficiency. The provision of rotor cavitation teeth with opposite rotation directions triggers a circulating flow of the gas-liquid phase, thereby improving the mass transfer efficiency.

[0060] like Figure 1 As shown, the present invention provides a wastewater degradation system with radial microchannel discharge and coordinated cavitation. In some embodiments, the system comprises a waste liquid pool 1, a microchannel discharge cavitation degradation device 8, an ozone generator 5, a venturi tube 6 and a collection pool 9. The ozone generator 5 is connected to the venturi tube 6, and the venturi tube 6 is respectively connected to the waste liquid pool 1 and the microchannel discharge cavitation degradation device 8, and the microchannel discharge cavitation degradation device 8 is connected to the collection pool 9; the ozone generator 5 is respectively connected to the venturi tube 6 and the air pump 3, and the air pump 3 inhales air to generate ozone in the oxygen generator 5, and the generated ozone is passed into the venturi tube 6; the wastewater in the waste liquid pool 1 generates a gas-liquid two-phase flow containing ozone microbubbles through the venturi tube 6, and the gas-liquid two-phase flow is pumped to the microchannel discharge cavitation degradation device 8 by a peristaltic pump 7; the microchannel discharge cavitation degradation device 8 is used to degrade the wastewater, and the waste liquid pool 1 is used to store industrial organic wastewater to be degraded.

[0061] Furthermore, the overflow valve 4 is connected to the degradation wastewater outlet 831 of the microchannel discharge cavitation degradation device 8 and the collection tank 9 through pipelines.

[0062] like Figure 2As shown, in one embodiment, the microchannel discharge cavitation degradation device 8 includes a drive mechanism 81, a conductive slip ring 82, a cavitation stator 83, a degradation device base 84, a cavitation rotor 85, and a radial microchannel discharge device 86. The drive mechanism 81 includes a cavitation rotor motor 811, which is fixed to a motor support 813 via bolts. The motor support 813 is connected to a drive mechanism fixing base 816 via bolts. The drive shaft upper bearing 814 and the drive shaft lower bearing 815 are mounted on the drive mechanism fixing base 816. The rotor drive shaft 812 is inserted into the concentric hole formed by the conductive slip ring 82, the drive shaft upper bearing 814, and the drive shaft lower bearing 815 to form a tight fit. The cavitation rotor 85 is located within the cavitation stator 83 and is connected to the rotor drive shaft 812 via threads. The rotor drive shaft 812 drives the cavitation rotor 85 to rotate.

[0063] like Figure 2-Figure 4 As shown, in one embodiment, a radial microchannel discharge device 86 is fixed between the cavitation stator 83 and the degradation device base 84 by bolts. The radial microchannel discharge device 86 includes a discharge device water inlet chamber 861, micro jet holes 862, an annular negative plate 863, a cylindrical discharge chamber 864, threaded holes 865, a discharge rod 866, an annular positive plate 867, and an annular cavity 868. A plurality of micro jet holes 862 are provided on the inner wall of the discharge device water inlet chamber 861. The micro jet holes 862 connect the discharge device water inlet chamber 861 with the cylindrical discharge chamber 864 and are radially distributed around the axis of the discharge device water inlet chamber 861. One end of the cylindrical discharge chamber 864 is connected to the annular negative plate 863, and the other end is connected to the inner cavitation chamber 834.

[0064] Figure 4 As shown, in one embodiment, a discharge rod 866 is screwed into a threaded hole 865. A sealed cavity is defined within discharge rod 866. An annular positive plate 867 is placed within the sealed cavity and tightly connected to the inner wall of discharge rod 866. An annular negative plate 863 is placed within an annular cavity 868 and tightly connected to the inner wall of annular cavity 868. Annular cavity 868 is in close contact with the outer wall of cylindrical discharge chamber 864. A small discharge gap is formed between the outer wall of discharge rod 866 and the inner wall of cylindrical discharge chamber 864. When industrial organic wastewater enters cylindrical discharge chamber 864 from discharge device water inlet chamber 861 through micro-jet holes 862, dielectric barrier discharge occurs within several cylindrical discharge chambers 864, creating a bulk discharge and significantly increasing the discharge area. In the existing technical solutions, the dielectric barrier discharge method is generally surface discharge between coaxial or parallel electrodes. The radial structure in the embodiment of the present application transforms the traditional surface discharge into body discharge, and also allows the dielectric barrier discharge area to extend all the way to the inner wall of the cavitation rotor 85, reducing the deactivation loss of active materials during transportation.

[0065] Figure 5 and Figure 6 As shown, in one embodiment, the cavitation rotor 85 includes outer wall cavitation teeth 851, inner wall cavitation teeth 852, a rotor annular positive pole 853, and a rotor cavitation channel 854. A plurality of equidistant outer wall cavitation teeth 851 are provided on the outer wall surface of the cavitation rotor 85 along the generatrix of the cylindrical outer wall, with a clockwise rotation direction. A plurality of equidistant axial grooves are formed between two adjacent outer wall cavitation teeth 851, and the groove surfaces of all axial grooves are parallel to the outer wall generatrix. A plurality of equidistant inner wall cavitation teeth 852 are provided on the inner wall surface of the cavitation rotor 85 along the generatrix of the conical inner wall, with a counterclockwise rotation direction. A plurality of equidistant grooves are formed between two adjacent inner wall cavitation teeth 852, and the groove surfaces of all grooves are parallel to the inner wall generatrix.

[0066] Furthermore, a plurality of equally spaced rotor cavitation channels 854 are radially opened between the outer wall and the inner wall of the cavitation rotor 85 , and are radially distributed with the axis of the cavitation rotor 85 as the center; the cavitation channels 854 connect the outer cavitation cavity 833 with the inner cavitation cavity 834 .

[0067] Figure 2 and Figure 5 As shown, as cavitation rotor 85 rotates, a narrow gap forms between outer wall cavitation teeth 851 and the inner wall of outer cavitation chamber 833. The gas-liquid flow rate suddenly increases within the narrow gap, causing a rapid drop in pressure. Meanwhile, an expanding chamber forms between the inter-tooth grooves and the inner wall of outer cavitation chamber 833, increasing the gas-liquid pressure. The alternating gaps and chambers of the narrow gaps and chambers as cavitation rotor 85 rotate continuously produce periodic pressure fluctuations, inducing a cavitation effect. A periodic alternation of wide and narrow channels also forms between inner wall cavitation teeth 852 and the outer wall of radial microchannel discharge device 86, triggering a cavitation effect between these two walls. The large number of cavitation bubbles generated inside and outside the rotor rapidly burst, releasing active substances and energy, which strongly degrades pollutants in the wastewater.

[0068] Figure 6 As shown, the rotor annular positive electrode 853 is disposed within the annular cavity of the cavitation rotor 85 and is tightly connected to the inner wall of the annular cavity 868. The rotor annular positive electrode 853 is in communication with the conductive slip ring 82. The rotor annular positive electrode 853 has through holes with the same orientation, number, and diameter as the rotor cavitation channels 854. The axes of the through holes coincide with the axes of the rotor cavitation channels 854. The surface of the rotor annular positive electrode 853 is waterproofed.

[0069] In the existing technical solutions, the cavitation rotor is generally a solid cylindrical gear-shaped structure. The cavitation rotor 85 with the inner cavitation cavity 834 in this embodiment has both discharge and cavitation functions around the outer wall cavitation teeth 851 and the inner wall cavitation teeth 852.

[0070] Figure 7 and Figure 9As shown, the cavitation stator 83 and the degradation device base 84 are tightly connected at the top and bottom by bolts. The cavitation stator 83 includes a degradation wastewater outlet 831 and a stator annular cathode 832. The degradation wastewater outlet 831 is located at the top of the outer cavitation chamber 833, penetrates the upper end surface of the cavitation stator 83, and is connected to the relief valve 4 via a pipe. The stator annular cathode 832 is located within the annular sealed cavity of the cavitation stator 83 and is tightly connected to the inner wall of the annular sealed cavity. A small discharge gap is formed between the inner wall of the cavitation stator 83 and the outer wall of the cavitation rotor 85.

[0071] Furthermore, to ensure that the dielectric barrier discharge can break through the gas-liquid phase discharge, the relative dielectric constant of the materials used for the cavitation stator 83, the cavitation rotor 85 and the discharge rod 866 should be greater than 3.8.

[0072] Figure 8 As shown, gas-liquid two-phase flow is introduced into the outer cavitation chamber 833 and the inner cavitation chamber 834, and the cavitation rotor 85 rotates stably at a certain speed. Based on the rotor's dimensional parameters and operating parameters, the torque output by the rotor motor 811 during operation can be accurately calculated, thereby meeting load requirements while avoiding excessive torque output and reducing energy consumption.

[0073] Assume that the viscosity of industrial wastewater is μ, in units of Pa·s, the rotational angular velocity of the cavitation rotor 85 is ω, in units of r / min, and the vertical distance from the rotor center axis to the rotor outer wall is r o , unit is m, the vertical distance from the rotor center axis to the stator inner wall is R, unit is m. The clearance of the cylinder wall is δ=Rr o , unit is m. The vertical distance from the upper surface to the lower surface of the rotor is L o , unit is m, according to Newton's law of internal friction, the friction force T on the outer wall of the rotor caused by the viscosity of the external cavitation cavity 833 industrial wastewater O , unit N, the friction force is calculated according to formula (1):

[0074]

[0075] Among them, τ is the shear stress on the outer wall of the rotor, and A is the outer surface area of the rotor. At this time, in order to balance the friction force T on the outer wall of the rotor o , the required torsional torque of the rotor is M O , unit N·m, the value of the torsional moment is calculated according to formula (2):

[0076] Assume that the vertical distance from the rotor center axis to the rotor inner wall is r i , unit is m, the vertical distance from the rotor center axis to the outer wall of the radial microchannel discharge device 86 is r, unit is m. Therefore, the gap between the rotor inner conical wall is δ′=r i-r, unit is m. The vertical distance from the upper surface of the rotor cavity to the bottom of the rotor is L i , unit is m, according to formula (2), in order to balance the friction force on the inner wall of the rotor, the required torsional torque of the rotor is M i , unit N·m, the value of the torsional moment is calculated according to formula (3):

[0077]

[0078] If the space between the outer wall and the inner wall of the rotor is filled with industrial wastewater, the torque required for the rotor to rotate at an angular velocity ω is obtained according to equations (2) and (3): r , unit N·m, the value of the total torsional moment is calculated according to formula (4):

[0079]

[0080] If the viscosity of wastewater is 3×10 -3 Pa·s, the cavitating rotor's angular velocity is 2000 r / min, the vertical distance from the rotor's upper surface to its lower surface is 0.1 m, and the vertical distance from the rotor's inner cavity's upper surface to its bottom surface is 0.15 m. The vertical distances from the rotor's central axis to the rotor's outer wall are 0.1 m, and the vertical distances from the rotor's central axis to the rotor's inner wall are 0.05 m. The clearance between the cylinder wall and the rotor's inner conical wall is 0.1 m, and the clearance between the rotor's inner conical wall is 0.1 m. The calculated minimum torque required is 0.12 N·m.

[0081] In summary, the minimum torsional torque required for cavitating rotor operation is calculated. Through torque balance analysis, the distribution of friction forces on the inner and outer walls of the cavitating rotor and the torque formula are calculated. Based on the relationship between industrial wastewater viscosity and speed, the speed is adjusted to minimize the rotor motor's output friction torque. This minimizes rotor energy consumption while meeting the process requirements for wastewater degradation and improving the economic efficiency of the degradation reaction.

[0082] like Figure 10 and Figure 11 As shown, the present invention also provides a wastewater degradation method using radial microchannel discharge and cavitation, which uses the above-mentioned wastewater degradation system using radial microchannel discharge and cavitation, including the following steps:

[0083] Step 1: The water tank 1 stores industrial organic wastewater, and the DC pump 2 and the air pump 3 are turned on to pump the industrial organic wastewater into the venturi tube 6. The ozone generated by the ozone generator 5 is simultaneously injected into the venturi tube 6 to fully mix the ozone and the industrial organic wastewater.

[0084] Step 2: The pressure inside the industrial organic wastewater is released at the throat of the venturi tube 6, producing a cavitation effect and generating a large number of microbubbles containing ozone. The industrial organic wastewater containing microbubbles is pumped into the microchannel discharge cavitation degradation device 8 through the peristaltic pump 7.

[0085] Step 3: The peristaltic pump 7 pumps the industrial organic wastewater containing microbubbles into the wastewater inlet 841. When the wastewater fills the entire cavity in the degradation device base 84, the wastewater enters the water inlet cavity 861 of the discharge device under the action of water pressure, and performs dielectric barrier discharge in the cylindrical discharge chamber 864 through the micro-jet holes 862, generating ozone and hydroxyl free radicals.

[0086] Step 4: After the industrial organic wastewater enters the inner cavitation cavity 834, the cavitation rotor motor 811 is started, and the cavitation rotor 85 rotates to induce a strong cavitation effect around the inner wall cavitation teeth 852. The organic wastewater is sucked from the inner cavitation cavity 834 into the outer cavitation cavity 833 through the rotor cavitation channel 854, and a dielectric barrier discharge is formed between the outer wall of the cavitation rotor 85 and the inner wall of the cavitation stator 83. Combined with the cavitation effect generated by the outer wall cavitation teeth 851, the industrial organic wastewater is deeply degraded.

[0087] Step 5: After the degradation wastewater outlet 831 reaches a certain water pressure, the overflow valve 4 opens the passage between the degradation wastewater outlet 831 and the collection tank 9, and the purified industrial organic wastewater flows into the collection tank 9 for storage.

[0088] The terms "first" and "second" appearing in the present invention are only for the convenience of description to distinguish different components with the same name, and do not indicate a priority or primary and secondary relationship.

[0089] In addition, when an element is referred to as being “on” another element, the element may be directly on the other element or may be indirectly on the other element with one or more intervening elements interposed therebetween. In addition, when an element is referred to as being “connected to” another element, the element may be directly connected to the other element or may be indirectly connected to the other element with one or more intervening elements interposed therebetween. Hereinafter, the same reference numerals denote the same elements.

[0090] The present invention uses the terms “upper”, “lower”, “top”, “bottom”, “front”, “back”, “inside” and “outside” to indicate directions or positional relationships. This is only for the convenience of describing the present invention, and does not indicate or imply that the device referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, it should not be understood as limiting the scope of protection of the present invention.

[0091] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wastewater degradation system using radial microchannel discharge and cavitation, characterized in that: include: A waste liquid pool (1), a microchannel discharge cavitation degradation device (8), an ozone generator (5), a venturi tube (6) and a collection pool (9), wherein the ozone generator (5) is connected to the venturi tube (6), the venturi tube (6) is respectively connected to the waste liquid pool (1) and the microchannel discharge cavitation degradation device (8), the microchannel discharge cavitation degradation device (8) is connected to the collection pool (9), and the ozone generator (5) is respectively connected to the venturi tube (6) and the air pump (3); The microchannel discharge cavitation degradation device (8) comprises a driving mechanism (81), a conductive slip ring (82) connected to the driving mechanism (81), a cavitation stator (83), a cavitation rotor (85) located in the cavitation stator (83), a degradation device base (84), and a radial microchannel discharge device (86) fixed between the cavitation stator (83) and the degradation device base (84); The radial microchannel discharge device (86) comprises a discharge device water inlet chamber (861), a plurality of micro jet holes (862) arranged on the inner wall of the discharge device water inlet chamber (861), an annular negative plate (863), a cylindrical discharge chamber (864), a threaded hole (865), a discharge rod (866) fixed in the threaded hole (865), an annular positive plate (867) and an annular cavity (868), wherein the micro jet holes (862) are connected to the discharge device water inlet chamber (861) and the cylindrical discharge chamber (864), and are radially arranged with the axis of the discharge device water inlet chamber (861) as the center. The cylindrical discharge chamber (864) is distributed in a shape; one end of the cylindrical discharge chamber (864) is connected to the annular negative plate (863), and the other end is connected to the inner cavitation cavity (834); the annular positive plate (867) is arranged in the sealed cavity of the discharge rod (866) and is tightly connected to the inner wall of the sealed cavity of the discharge rod (866); the annular negative plate (863) is arranged in the annular cavity (868) and is tightly connected to the inner wall of the annular cavity (868); the annular cavity (868) is closely attached to the outer wall of the cylindrical discharge chamber (864); a small discharge gap is formed between the outer wall of the discharge rod (866) and the inner wall of the cylindrical discharge chamber (864); The outer wall surface of the cavitation rotor (85) is provided with a plurality of equidistant outer wall cavitation teeth (851) along the direction of the cylindrical outer wall generatrix, the rotation direction is clockwise, and a plurality of equidistant axial grooves are formed between two adjacent outer wall cavitation teeth (851), and the groove surfaces of all the axial grooves are parallel to the outer wall generatrix; the inner wall surface of the cavitation rotor (85) is provided with a plurality of equidistant inner wall cavitation teeth (852) along the direction of the conical inner wall generatrix, the rotation direction is counterclockwise, and a plurality of equidistant grooves are formed between two adjacent inner wall cavitation teeth (852), and the groove surfaces of all the grooves are parallel to the inner wall generatrix; a slit is formed between the outer wall cavitation teeth (851) and the inner wall of the outer cavitation cavity (833), and an expanded chamber is formed between the inter-tooth grooves and the inner wall of the outer cavitation cavity (833), and the slit and the chamber are continuously alternated as the cavitation rotor (85) rotates; The cavitation stator (83) comprises a degradation wastewater outlet (831) and a stator annular negative electrode (832). The degradation wastewater outlet (831) is opened at the top of the outer cavitation cavity (833), passes through the upper end surface of the cavitation stator (83), and is connected to the overflow valve (4) through a pipeline; the stator annular negative electrode (832) is arranged in the annular sealed cavity in the cavitation stator (83), and is tightly connected to the inner wall of the annular sealed cavity. A small discharge gap is formed between the inner wall of the cavitation stator (83) and the outer wall of the cavitation rotor (85).

2. The wastewater degradation system according to claim 1, characterized in that: It is also provided with a peristaltic pump (7) and an overflow valve (4). The peristaltic pump (7) is used to generate a gas-liquid two-phase flow containing ozone microbubbles from wastewater in the waste liquid pool (1) through a venturi tube (6), and the gas-liquid two-phase flow is sent to a microchannel discharge cavitation degradation device (8). The overflow valve (4) is respectively connected to the microchannel discharge cavitation degradation device (8) and a collection pool (9). The two ends of the DC pump (2) are respectively connected to the waste liquid pool (1) and the venturi tube (6).

3. The wastewater degradation system according to claim 1, characterized in that: The driving mechanism (81) comprises a rotor driving shaft (812), a motor support seat (813), a cavitation rotor motor (811) fixedly mounted on the motor support seat (813), a driving mechanism fixing seat (816) fixedly connected to the motor support seat (813), and a driving shaft upper bearing (814) and a driving shaft lower bearing (815) fixedly mounted on the driving mechanism fixing seat (816). The rotor driving shaft (812) is inserted into a concentric hole formed by a conductive slip ring (82), the driving shaft upper bearing (814), and the driving shaft lower bearing (815) to form a tight fit. The rotor driving shaft (812) is connected to the cavitation rotor (85), and the rotor driving shaft (812) drives the cavitation rotor (85) to rotate.

4. The wastewater degradation system according to claim 1, characterized in that: A plurality of equally spaced rotor cavitation channels (854) are radially opened between the outer wall and the inner wall of the cavitation rotor (85), and are radially distributed with the axis of the cavitation rotor (85) as the center. The rotor cavitation channels (854) connect the outer cavitation cavity (833) and the inner cavitation cavity (834).

5. The wastewater degradation system according to claim 1, characterized in that: The relative dielectric constant of the materials used for the cavitation stator (83), the cavitation rotor (85) and the discharge rod (866) should be greater than 3.

8.

6. The wastewater degradation system according to claim 1, characterized in that: A gas-liquid two-phase flow is introduced into the outer cavitation cavity (833) and the inner cavitation cavity (834), and the cavitation rotor (85) rotates stably at a certain speed. The torque output by the cavitation rotor motor (811) during operation is calculated based on the rotor's size parameters and operating parameters. Assume that the viscosity of industrial wastewater is ,unit , the rotational angular velocity of the cavitation rotor (85) is ,unit , the vertical distance from the rotor center axis to the rotor outer wall is , unit is m, the vertical distance from the rotor center axis to the stator inner wall is , unit m, the clearance of the cylinder wall is , unit is m, the vertical distance from the upper surface to the lower surface of the rotor is , unit is m. According to Newton’s law of internal friction, the friction force on the outer wall of the rotor caused by the viscosity of the industrial wastewater in the outer cavitation cavity (833) is , unit N, the friction force is calculated according to formula (1): in, is the shear stress on the outer wall of the rotor, is the outer surface area of the rotor. In order to balance the friction force on the outer wall of the rotor, The required torsional torque of the rotor is ,unit , the value of the torsional moment is calculated according to formula (2): Assume that the vertical distance from the rotor center axis to the rotor inner wall is , unit is m, the vertical distance from the rotor center axis to the outer wall of the radial microchannel discharge device (86) is , unit is m, the clearance of the conical wall inside the rotor is , unit is m, the vertical distance from the upper surface of the rotor cavity to the bottom surface of the rotor is , unit is m, according to formula (2), in order to balance the friction force on the inner wall of the rotor, the required torsional torque of the rotor is ,unit , the value of the torsional moment is calculated according to formula (3): If the space between the outer wall and the inner wall of the rotor is filled with industrial wastewater, according to equations (2) and (3), the angular velocity is The torque required to rotate the rotor is ,unit , the value of the total torsional moment is calculated according to formula (4): When measuring the viscosity of industrial wastewater and the rotational angular velocity of the cavitation rotor (85) Then, the torque value required for the rotor to work is calculated according to formula (4), and the torque of the cavitation rotor motor (811) is adjusted so that the cavitation rotor (85) operates with the minimum torsional torque, thereby reducing the energy consumption of the cavitation rotor motor (811).

7. A wastewater degradation method using radial microchannel discharge and cavitation, using the wastewater degradation system according to any one of claims 1 to 6, characterized in that: The method comprises: Step 1: The waste liquid pool (1) stores industrial organic wastewater, the DC pump (2) and the air pump (3) are turned on, and the industrial organic wastewater is pumped into the venturi tube (6). The ozone generated by the ozone generator (5) is simultaneously injected into the venturi tube (6) to fully mix the ozone and the industrial organic wastewater. Step 2: The pressure inside the industrial organic wastewater is released at the throat of the venturi tube (6), generating a cavitation effect and generating a large number of microbubbles containing ozone. The industrial organic wastewater containing microbubbles is pumped into the microchannel discharge cavitation degradation device (8) through a peristaltic pump (7); Step 3: The peristaltic pump (7) pumps the industrial organic wastewater containing microbubbles into the wastewater injection port (841). When the wastewater fills the entire cavity in the degradation device base (84), the wastewater enters the discharge device water inlet cavity (861) under the action of water pressure, and performs dielectric barrier discharge in the cylindrical discharge chamber (864) through the micro-jet holes (862), generating ozone and hydroxyl radicals. Step 4: After the industrial organic wastewater enters the inner cavitation cavity (834), the cavitation rotor motor (811) is started, and the cavitation rotor (85) rotates to induce a strong cavitation effect around the inner wall cavitation teeth (852). The organic wastewater is sucked from the inner cavitation cavity (834) into the outer cavitation cavity (833) through the rotor cavitation channel (854), and a dielectric barrier discharge is formed between the outer wall of the cavitation rotor (85) and the inner wall of the cavitation stator (83). The cavitation effect generated by the outer wall cavitation teeth (851) is combined with the cavitation effect to deeply degrade the industrial organic wastewater. Step 5: After the degradation wastewater outlet (831) reaches a certain water pressure, the overflow valve (4) opens the passage between the degradation wastewater outlet (831) and the collection tank (9), and the purified industrial organic wastewater flows into the collection tank (9) for storage.

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