A wastewater treatment device with synergistic effect of ozone oxidation and hydrodynamic cavitation

Abstract

The present application belongs to the field of wastewater advanced oxidation treatment technology, and proposes a wastewater treatment device with ozone oxidation and hydraulic cavitation synergistic effect. A primary Venturi tube, a ring air guide structure, a ring gap and a gas-liquid initial mixing section are arranged. The hydraulic cavitation is realized through the primary Venturi tube, the cavitation bubbles formed are extended to the downstream along the expansion section, and the synergistic effect with the ozone entering through the ring gap is realized. In the extreme environment generated by the collapse of the cavitation bubbles, the dissolution of the ozone gas into the liquid and the generation of the hydroxyl radicals are promoted. To some extent, the dependence on the pressure gas source is reduced, and the energy consumption is reduced. The gas phase is preliminarily dispersed before entering the secondary Venturi tube, the uniformity of the gas-liquid in the flow space is realized to the maximum extent, and the choked flow is easy to form. On the one hand, the bubbles can be further micronized, and the mass transfer is strengthened. At the same time, the gas-liquid interface changes sharply in the process of bubble micronization, which is also beneficial to the efficient generation of the hydroxyl radicals, so as to further improve the wastewater treatment efficiency.

Description

Technical Field

[0001] This invention relates to the field of advanced wastewater oxidation treatment technology, and in particular to a wastewater processor that combines ozone oxidation and hydraulic cavitation. Background Technology

[0002] Industries such as coal chemical, petrochemical, papermaking, and textiles generate large amounts of wastewater containing organic matter during production. This wastewater is characterized by large discharge volumes, stable properties, high organic content, toxicity, and reluctance to degrade. Direct discharge without treatment poses serious threats to natural water bodies and human health. Conventional biological treatment methods are insufficient to completely degrade or remove this type of organic wastewater. However, advanced oxidation technologies, which can directly mineralize organic pollutants or enhance their biodegradability through oxidation, thereby achieving complete mineralization or decomposition of the vast majority of organic matter, have broad application prospects.

[0003] Ozone oxidation is an advanced oxidation technology that treats organic wastewater primarily through two pathways: direct and indirect reactions. In the direct reaction, ozone reacts directly with organic matter, a process exhibiting strong selectivity. In the indirect reaction, ozone decomposes to produce hydroxyl radicals (·OH), which then oxidize organic matter, a process also exhibiting selectivity. Without the introduction of other reagents or catalysts, or by coupling with other advanced oxidation technologies, ozone oxidation technology suffers from drawbacks such as low ozone utilization and limited oxidation capacity.

[0004] Hydraulic cavitation is another advanced oxidation technology. It utilizes hydraulic structures (such as venturi tubes, orifice plates, or throttling valves) to reduce the local pressure of a liquid. When the pressure falls below the saturated vapor pressure of the liquid at the current temperature, cavitation bubbles are generated. As the liquid pressure subsequently recovers, the cavitation bubbles formed earlier collapse and shrink. The hydraulic cavitation process can create extreme physicochemical fields, enabling high-temperature thermal decomposition, highly reactive free radical oxidation, and supercritical water oxidation of recalcitrant organic matter. While hydraulic cavitation technology does not require the addition of other reagents, it suffers from drawbacks such as a limited extreme environment and low free radical production, resulting in low treatment efficiency.

[0005] If ozone oxidation and hydraulic cavitation can be synergistically achieved through wastewater treatment, the extreme environment created by hydraulic cavitation can be utilized to promote effective contact between ozone gas and organic pollutants in the water, reduce mass transfer barriers, improve ozone utilization, and enhance the generation of hydroxyl radicals. However, commonly used methods such as Venturi cavitation and perforated plate cavitation still face the challenge of achieving synergistic effects between ozone oxidation and hydraulic cavitation. Summary of the Invention

[0006] The purpose of this invention is to provide an organic wastewater processor that combines ozone oxidation and hydraulic cavitation, which features a compact structure, convenient manufacturing, high efficiency, and low energy consumption, and effectively solves the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a wastewater processor with synergistic effects of ozone oxidation and hydraulic cavitation, comprising: an inflow section 1, a primary Venturi tube 2, a circumferential air intake structure 3, a circumferential gap 4, a gas-liquid initial mixing chamber 5, a transition section 6, a secondary Venturi tube 7, and an outflow section 8, all eight being coaxial; the inflow section 1 is directly connected to one end of the primary Venturi tube 2; the primary Venturi tube 2 includes, from bottom to top, a primary contraction section 201, a primary throat section 202, and a primary expansion section 203; a circumferential air intake structure 3 is arranged on the outer side of the primary Venturi tube 2; the circumferential air intake structure 3 is provided with a radial air inlet 301 and an axial air outlet 303. An annular air cavity 302 is formed between the first-stage Venturi tube 2 and the outer side of the first-stage Venturi tube 2; the circumferential air intake structure 3 is in contact with one end of the gas-liquid primary mixing cavity 5; the gas-liquid primary mixing cavity 5 is an inverted frustum, and the other end of the first-stage Venturi tube 2 is located inside the gas-liquid primary mixing cavity 5; an annular gap 4 is formed between the gas-liquid primary mixing cavity 5 and the first-stage expansion section 203, and the annular gap 4 is connected to the axial vent 303; the other end of the gas-liquid primary mixing cavity 5 is connected in sequence to the transition section 6, the second-stage Venturi tube 7 and the outflow section 8; the transition section 6 is a straight pipe; the second-stage Venturi tube 7 includes, from bottom to top, a second-stage contraction section 701, a second-stage throat 702 and a second-stage expansion section 703; the outflow section 8 is a straight pipe.

[0008] The circumferential gap 4 is at an angle to the central axis of the wastewater processor. Changing the angle controls the size of the bubbles dispersed from the gas entering the gas-liquid primary mixing chamber 5 through the circumferential gap 4.

[0009] The first-stage venturi tube 2 has a first-stage contraction section 201 and a first-stage expansion section 203, both of which are straight conical sections. The contraction angle of the first-stage contraction section 201 is 20° to 45°, and the expansion angle of the first-stage expansion section 203 is 10° to 30°. The first-stage throat section 202 is a straight tube.

[0010] The secondary contraction section 701 of the secondary venturi tube 7 is a smooth curve, and the minimum flow cross section is the secondary throat 702. The secondary contraction section 701 transitions directly to the secondary expansion section 703 through the secondary throat 702. The secondary expansion section 703 is a straight cone, and the expansion angle of the secondary expansion section 703 is 3° to 20°.

[0011] The radial air inlet 301 is a radial through hole, numbered 1 to 4, and evenly distributed along the circumference; the axial air outlet 303 is an axial through hole, numbered 6 to 12, and evenly distributed along the circumference.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] (1) The wastewater processor is equipped with a first-stage Venturi tube, which realizes hydraulic cavitation through the first-stage Venturi tube. The cavitation bubbles formed extend downstream along the expansion section and work synergistically with the ozone that enters through the circumferential air intake structure. Under the extreme environment generated by the collapse of the cavitation bubbles, the ozone gas is dissolved into the liquid and hydroxyl radicals are generated, thereby improving the ozone utilization rate and wastewater treatment efficiency.

[0014] (2) The wastewater processor achieves air intake through a circumferential air intake structure, which can reduce the dependence on pressurized air source to a certain extent and reduce energy consumption.

[0015] (3) The wastewater processor is equipped with a gas-liquid initial mixing section, which advances the gas-liquid two-phase mixing process. This allows the gas phase to be initially dispersed before entering the secondary Venturi tube, maximizing the uniformity of gas and liquid in the flow space and making it easy to form a choke flow. On the one hand, this allows the bubbles to be further miniaturized, thereby enhancing mass transfer. On the other hand, the drastic changes in the gas-liquid interface during the bubble miniaturization process also facilitate the efficient generation of hydroxyl radicals, thereby further improving the wastewater treatment efficiency. Attached Figure Description

[0016] Figure 1 A cross-sectional view of a wastewater treatment system that combines ozone oxidation and hydraulic cavitation.

[0017] Figure 2 for Figure 1 Sectional view of section AA in the image;

[0018] In the diagram: 1. Inflow section, 2. First-stage Venturi tube, 201. First-stage contraction section, 202. First-stage throat section, 203. First-stage expansion section, 3. Circumferential air intake structure, 301. Radial air inlet, 302. Annular air chamber, 303. Axial air vent, 4. Circumferential gap, 5. Gas-liquid initial mixing chamber, 6. Transition section, 7. Second-stage Venturi tube, 701. Second-stage contraction section, 702. Second-stage throat, 703. Second-stage expansion section, 8. Outflow section. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the technical solutions of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figures 1-2 This invention provides a wastewater treatment system that combines ozone oxidation and hydraulic cavitation, comprising:

[0021] The system consists of eight parts: inlet section 1, primary venturi tube 2, circumferential air intake structure 3, circumferential gap 4, gas-liquid primary mixing chamber 5, transition section 6, secondary venturi tube 7, and outlet section 8. All eight parts are coaxial and connected by welding or flanges. The upper end of the inflow section 1 is connected to the lower end of the first-stage Venturi tube 2, and the liquid phase enters from the bottom of the inflow section 1 from bottom to top; the first-stage Venturi tube 2 includes, from bottom to top, a first-stage contraction section 201, a first-stage throat section 202, and a first-stage expansion section 203; the circumferential air intake structure 3 includes a radial air inlet 301, an annular air chamber 302, and an axial air passage 303; the radial air inlet 301 is a radial through hole; the axial air passage 303 is an axial through hole; the circumferential gap 4 is an upright frustum; the gas-liquid initial mixing chamber 5 is an inverted frustum; the transition section 6 is a straight pipe; the second-stage Venturi tube 7 includes a second-stage contraction section 701, a second-stage throat 702, and a second-stage expansion section 703; the outflow section 8 is a straight pipe.

[0022] Furthermore, the first-stage contraction section and the first-stage expansion section of the first-stage Venturi tube are both straight conical sections with a contraction angle of 20° to 45° and an expansion angle of 10° to 30°, and the throat section is a straight tube.

[0023] Furthermore, the number of radial air inlets in the circumferential air intake structure is 1 to 4, evenly distributed along the circumference, and the number of axial air vents is 6 to 12, evenly distributed along the circumference.

[0024] Furthermore, there is a circumferential gap 4 between the gas-liquid primary mixing chamber and the expansion section of the first-stage Venturi tube. The circumferential gap 4 is at an angle to the central axis of the wastewater processor. Changing the angle controls the size of the gas bubbles that enter the gas-liquid primary mixing chamber 5 through the circumferential gap 4.

[0025] Furthermore, the contraction section of the secondary venturi tube is a smooth curve, the minimum flow cross-section is the throat, the secondary contraction section transitions directly to the expansion section through the throat, the secondary expansion section is a straight cone, and the expansion angle of the secondary expansion section is 3° to 20°.

[0026] Working principle: Liquid first enters the device from the inflow section 1, then flows upward into the first-stage Venturi tube 2. After passing through the contraction section 201, the liquid velocity increases and the local pressure decreases. When the pressure is lower than the saturated vapor pressure corresponding to the local temperature of the liquid, cavitation bubbles are generated. The cavitation bubbles flow downstream with the liquid into the gas-liquid primary mixing section 5. Ozone gas enters the annular gas chamber 302 through the radial air inlet 301 of the circumferential air intake structure 3, and forms a jet through the axial air outlet 303 via the annular gap 4 between the gas-liquid primary mixing chamber and the first-stage Venturi tube, entering the gas-liquid primary mixing chamber to form dispersed bubbles. The ozone bubbles come into contact with the liquid flow mixed with cavitation bubbles flowing out of the expansion section 203 and have a synergistic effect, cavitation. The extreme physicochemical environment generated by bubble collapse can treat organic wastewater and further promote the dissolution of ozone gas into the liquid and the generation of hydroxyl radicals, thereby improving ozone utilization and wastewater treatment efficiency. The gas-liquid two-phase flow flows into the secondary venturi tube 7 through the transition section 6, and after acceleration in the secondary contraction section 701, it reaches congestion at the secondary throat 702, thus forming an extreme gas-liquid two-phase flow field in the secondary expansion section 703. This allows for further bubble miniaturization, enhancing mass transfer and forming ozone water. Simultaneously, the drastic changes in the gas-liquid interface during bubble miniaturization also promote the efficient generation of hydroxyl radicals, further improving wastewater treatment efficiency. Finally, the ozone water containing microbubbles flows out from the outlet section 8.

[0027] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wastewater treatment device using synergistic effect of ozone oxidation and hydrodynamic cavitation, characterized in that, The wastewater treatment device with synergistic effect of ozone oxidation and hydrodynamic cavitation comprises an inflow section (1), a first-stage Venturi tube (2), a ring air guide structure (3), a ring gap (4), a gas-liquid primary mixing cavity (5), a transition section (6), a second-stage Venturi tube (7) and an outflow section (8), which are coaxial; the inflow section (1) is directly communicated with one end of the first-stage Venturi tube (2); the first-stage Venturi tube (2) comprises a first-stage contraction section (201), a first-stage throat section (202) and a first-stage expansion section (203) from bottom to top in sequence; the ring air guide structure (3) is arranged outside the first-stage Venturi tube (2); the ring air guide structure (3) is provided with radial air inlet holes (301) and axial air outlet holes (303), and an annular air cavity (302) is formed between the ring air guide structure (3) and the outside of the first-stage Venturi tube (2); the ring air guide structure (3) is in contact with one end of the gas-liquid primary mixing cavity (5); the gas-liquid primary mixing cavity (5) is an inverted circular truncated cone, and the other end of the first-stage Venturi tube (2) is located inside the gas-liquid primary mixing cavity (5); the ring gap (4) is formed between the gas-liquid primary mixing cavity (5) and the first-stage expansion section (203), and is communicated with the axial air outlet holes (303); the other end of the gas-liquid primary mixing cavity (5) is sequentially connected with the transition section (6), the second-stage Venturi tube (7) and the outflow section (8); the transition section (6) is a straight pipe; the second-stage Venturi tube (7) comprises a second-stage contraction section (701), a second-stage throat (702) and a second-stage expansion section (703) from bottom to top in sequence; the outflow section (8) is a straight pipe; wastewater first enters the device from the inflow section (1), and then enters the first-stage Venturi tube (2) upward; after passing through the tapered contraction section (201), the flow rate of the wastewater is increased, and the local pressure is reduced; when the pressure is lower than the saturated steam pressure corresponding to the local temperature of the wastewater, cavitation bubbles are generated; the cavitation bubbles flow downstream with the wastewater into the gas-liquid primary mixing cavity (5); ozone gas enters the annular air cavity (302) through the radial air inlet holes (301) of the ring air guide structure (3) and forms a jet through the axial air outlet holes (303) and the ring gap (4) between the gas-liquid primary mixing cavity and the first-stage Venturi tube, and enters the gas-liquid primary mixing cavity to form dispersed bubbles; the ozone bubbles contact the liquid stream mixed with cavitation bubbles flowing out of the expansion section (203) to have a synergistic effect; the extreme physical and chemical environment generated by the collapse of the cavitation bubbles realizes the treatment of the wastewater, and further promotes the dissolution of ozone gas into the wastewater and the generation of hydroxyl radicals, so as to improve the utilization rate of ozone and the wastewater treatment efficiency; the gas-liquid two-phase flows into the second-stage Venturi tube (7) through the transition section (6), is accelerated after passing through the second-stage contraction section (701), reaches the choke point at the second-stage throat (702), and forms an extreme gas-liquid two-phase flow field in the second-stage expansion section (703), which on the one hand makes the bubbles further fine, realizes mass transfer intensification and forms ozone water; meanwhile, the gas-liquid interface changes sharply in the process of bubble fine, which is also beneficial to the efficient generation of hydroxyl radicals, so as to further improve the wastewater treatment efficiency; finally, the ozone water containing micro-bubbles flows out from the outflow section (8). The expansion angle of the first expansion section (203) is 10°-30°, and the expansion angle of the second expansion section (703) is 3°-20°. The annular gap (4) is at an angle to the central axis of the wastewater treatment device, and changing the angle controls the size of the bubbles into which the gas entering the gas-liquid primary mixing chamber (5) through the annular gap (4) is dispersed.

2. The ozone oxidation and hydrodynamic cavitation synergized wastewater treatment device according to claim 1, characterized in that, The first contraction section (201) and the first expansion section (203) of the first Venturi tube (2) are straight circular cones, the contraction angle of the first contraction section (201) is 20°-45°, and the first throat section (202) is a straight pipe.

3. The ozone oxidation and hydrodynamic cavitation synergized wastewater treatment device according to claim 2, characterized in that, The second contraction section (701) of the second Venturi tube (7) is a smooth curve, the smallest flow cross section is the second throat (702), the second contraction section (701) directly transitions to the second expansion section (703) through the second throat (702), and the second expansion section (703) is a straight circular cone.

4. The ozone oxidation and hydrodynamic cavitation synergized wastewater treatment device according to claim 3, characterized in that, The radial gas inlet holes (301) are radial through holes, the number is 1-4, and they are uniformly distributed in the circumferential direction; the axial air holes (303) are axial through holes, the number is 6-12, and they are uniformly distributed in the circumferential direction.

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