Ozone catalytic oxidation system

Abstract

The utility model provides a kind of ozone catalytic oxidation system, it is related to wastewater treatment technical field, comprising: bubble generator, bubble generator includes the microporous aerator head, venturi mixer and spiral turbulator connected in turn, the liquid inlet of venturi mixer is used for being handled liquid injection;Ozone supply device, the output end of ozone supply device is connected in proper order the gas inlet of microporous aerator head and venturi mixer;Reactor, the lower end of reactor is provided with inlet, and inlet is connected with spiral turbulator, catalyst is provided in reactor, and the upper end of reactor is provided with outlet;Solve the problem that the bubble particle size generated by aeration in conventional ozone oxidation process in the prior art is relatively large, and the gas-liquid mass transfer efficiency is low.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, and more specifically, relates to an ozone catalytic oxidation system. Background Technology

[0002] In the field of industrial wastewater treatment, ozone oxidation technology is widely used due to its advantages such as strong oxidizing power, fast reaction speed, and no secondary pollution. However, traditional ozone oxidation processes have the following shortcomings:

[0003] 1. Low gas-liquid mass transfer efficiency; conventional aeration produces large bubble sizes, generally greater than 1 mm, and the solubility of ozone in water is only 40-60 mg / L, with a mass transfer coefficient KLa less than 100 h⁻¹. -1 This results in ozone utilization rates generally being below 60%.

[0004] 2. Limited catalytic effect; commercially available particulate catalysts, such as activated carbon and TiO2, have a small specific surface area, generally less than 80m². 2 / g, with uneven distribution of active sites, insufficient catalytic efficiency for ozone decomposition, low yield of hydroxyl radicals (·OH), and a removal rate of only 20-30% for recalcitrant organic matter.

[0005] 3. Difficulty in solid-liquid separation: In traditional fluidized bed or fixed bed reactors, catalyst particles with a diameter of 0.5-2mm are prone to clogging and loss, requiring frequent replacement and increasing operating costs. Utility Model Content

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing an ozone catalytic oxidation system that solves the problems of large bubble size and low gas-liquid mass transfer efficiency in traditional ozone oxidation processes.

[0007] To achieve the above objectives, this utility model provides an ozone catalytic oxidation system, comprising:

[0008] A bubble generating device, comprising a microporous aerator, a Venturi mixer, and a spiral turbulence generator connected in sequence, wherein the liquid inlet of the Venturi mixer is used for injecting the liquid to be treated;

[0009] An ozone supply device, the output of which is sequentially connected to the gas inlet of the microporous aerator and the Venturi mixer;

[0010] The reactor has an inlet at its lower end, which is connected to the helical turbulence generator. The reactor contains a catalyst, and the reactor has an outlet at its upper end.

[0011] Optionally, the two ends of the microporous aerator are connected to the ozone supply device and the Venturi mixer respectively through pipelines, and the pore size of the aeration holes of the microporous aerator is 2-5μm.

[0012] Optionally, it also includes a water tank for containing the liquid being treated, and a pump connected between the water tank and the liquid inlet of the Venturi mixer.

[0013] Optionally, the reactor is provided with a mixing zone and a catalytic reaction zone from bottom to top, the mixing zone is connected to the catalytic reaction zone, and the catalytic reaction zone is provided with a catalyst inlet.

[0014] Optionally, the catalyst is a metal catalyst supported on hydroxyapatite.

[0015] Optionally, the reactor is provided with baffles on the inner wall of the catalytic reaction zone, and a plurality of baffles are evenly distributed along the circumference of the reactor.

[0016] Optionally, the top of the reactor is provided with an exhaust port, which is connected to an ozone exhaust gas destroyer.

[0017] Optionally, the outlet is connected to a hydrocyclone separator, the lower end of which is provided with a catalyst outlet, and the upper end of which is provided with a liquid phase outlet.

[0018] Optionally, the outlet is connected to the cyclone separator via a first air-lift device.

[0019] Optionally, the catalyst outlet is connected to the reactor via a second stripping device.

[0020] This invention provides an ozone catalytic oxidation system with the following advantages: The system includes a bubble generator. The bubble generator first breaks down ozone supplied by the ozone supply device into micron-sized bubbles with a diameter of 2-5 μm through a microporous aerator head. These bubbles are then fed into the gas inlet of a Venturi mixer. The liquid to be treated is injected through the liquid inlet of the Venturi mixer. The negative pressure generated by the liquid flow draws in the micron-sized bubbles and shears them into microbubbles with a diameter of 400-1000 nm. The gas-liquid mixture then enters a spiral turbulence generator, where turbulence further refines most of the bubbles to a diameter of no more than 400 nm. The spiral turbulence generator is connected to a reactor, where the liquid to be treated and the ozone bubbles enter the reactor for catalytic oxidation, achieving purification of the liquid. This ozone catalytic oxidation system can generate ozone bubbles with smaller diameters, effectively improving mass transfer efficiency and shortening reaction time.

[0021] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0022] The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings, in which like reference numerals generally represent like parts.

[0023] Figure 1 A schematic diagram of an ozone catalytic oxidation system according to an embodiment of the present invention is shown.

[0024] Figure 2 A schematic diagram of the structure of a reactor in an ozone catalytic oxidation system according to an embodiment of the present invention is shown.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Microporous aerator head; 2. Venturi mixer; 3. Spiral turbulence generator; 4. Ozone supply device; 5. Reactor; 6. Catalyst; 7. Control unit; 8. Water tank; 9. Pump; 10. Catalyst inlet; 11. Baffle plate; 12. Ozone tail gas destroyer; 13. Cyclone separator; 14. First air lift device; 15. Second air lift device; 16. First blower; 17. Second blower. Detailed Implementation

[0027] Preferred embodiments of the present invention will now be described in more detail. While preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0028] like Figure 1 As shown, this utility model provides an ozone catalytic oxidation system, comprising:

[0029] The bubble generating device includes a microporous aerator 1, a Venturi mixer 2 and a spiral turbulence generator 3 connected in sequence. The liquid inlet of the Venturi mixer 2 is used for injecting the liquid to be treated.

[0030] Ozone supply device 4, the output end of ozone supply device 4 is connected in sequence to the gas inlet of microporous aeration head 1 and Venturi mixer 2;

[0031] Reactor 5 has an inlet at its lower end, which is connected to the spiral turbulence generator 3. The reactor 5 contains a catalyst 6, and the reactor 5 has an outlet at its upper end.

[0032] Specifically, to address the problem of large bubble size and low gas-liquid mass transfer efficiency in traditional ozone oxidation processes, this invention provides an ozone catalytic oxidation system with a bubble generating device. This device first breaks down ozone supplied by the ozone supply device 4 into micron-sized bubbles with a diameter of 2-5 μm through a microporous aeration head 1. These bubbles are then fed into the gas inlet of a Venturi mixer 2. The liquid to be treated is injected through the liquid inlet of the Venturi mixer 2. The negative pressure generated by the liquid flow draws in the micron-sized bubbles and shears them into microbubbles with a diameter of 400-1000 nm. The gas-liquid mixture then enters a spiral turbulence generator 3, where turbulence further refines most of the bubbles (e.g., a proportion of not less than 85%) to a diameter of no more than 400 nm. The spiral turbulence generator 3 is connected to a reactor 5. The liquid to be treated and the ozone bubbles enter the reactor 5 for catalytic oxidation, achieving purification of the liquid. This ozone catalytic oxidation system can generate ozone bubbles with smaller diameters, effectively improving mass transfer efficiency and shortening reaction time.

[0033] In this embodiment, the ozone supply device 4 adopts a high-frequency ceramic ozone generator, and the input gas source is medical oxygen or liquid oxygen with a purity of ≥99.2%. The ozone concentration adjustment range is 50-200mg / L, which is precisely controlled by a gas flow controller. An ozone concentration detector with an accuracy of ±0.5mg / L is also provided to monitor the ozone output concentration in real time and can be used for feedback adjustment.

[0034] Furthermore, in this embodiment, a control unit 7 is also included. The control unit 7 is connected to the COD monitoring instrument of the liquid being treated, the ozone supply device 4, and the gas flow controller. The control unit 7 can integrate a PLC controller to receive the ozone concentration and the COD concentration of the liquid being treated in real time, and adjust the ozone dosage. The basic adjustment logic is that the higher the COD concentration of the liquid being treated, the greater the amount of ozone added. In one example, the ozone generation can be automatically adjusted by a PID algorithm, and the adjustment accuracy can be controlled within ±5%.

[0035] Optionally, the two ends of the microporous aeration head 1 are connected to the ozone supply device 4 and the Venturi mixer 2 respectively through pipelines, and the pore size of the aeration holes of the microporous aeration head 1 is 2-5μm.

[0036] Specifically, the output end of the ozone supply device 4 is connected to the ozone input end of the microporous aerator head 1 through the first pipeline. The ozone output end of the microporous aerator head 1 can be connected to a cylindrical component, which is connected to a second pipeline, and then connected to the gas inlet of the Venturi mixer 2 through the second pipeline.

[0037] In this embodiment, the microporous aeration head 1 is a titanium alloy microporous aeration head 1 with a porosity of 45% for the aeration holes.

[0038] Optionally, it also includes a water tank 8 and a pump 9, the water tank 8 being used to contain the liquid being processed, and the pump 9 being connected between the water tank 8 and the liquid inlet of the Venturi mixer 2.

[0039] Specifically, the liquid to be treated can first be contained in a water tank 8, which is connected to the liquid inlet of the Venturi mixer 2 via a liquid delivery line. The pump 9 installed on the liquid delivery line can pump the liquid to be treated to the Venturi mixer 2, ensuring a high liquid flow rate. The high flow rate creates a negative pressure in the Venturi mixer 2, which draws in ozone bubbles and shears them to form smaller ozone bubbles.

[0040] In this embodiment, the flow rate of the liquid being processed is 5 m / s.

[0041] In this embodiment, the throat diameter of the Venturi mixer 2 is 25 mm.

[0042] In this embodiment, the helical turbulence generator 3 has helical blades with a pitch of 100 mm and an angle of 45° relative to the axis.

[0043] Optionally, the reactor 5 is provided with a mixing zone and a catalytic reaction zone from bottom to top, the mixing zone and the catalytic reaction zone are connected, and the catalytic reaction zone is provided with a catalyst inlet 10.

[0044] Specifically, the liquid to be treated and ozone bubbles enter the mixing zone and form an upflow. The catalyst can enter the catalytic reaction zone through the catalyst inlet 10. The reactor 5 adopts a fluidized bed operation mode, and the aeration effect generated by the gas input promotes the fluidization state of the catalyst 6.

[0045] In this embodiment, the outer shell of reactor 5 is made of ozone-resistant 316L stainless steel and is cylindrical in shape. The interior is divided into two functional zones from bottom to top: a mixing zone and a catalytic reaction zone.

[0046] Optionally, catalyst 6 is a metal catalyst supported on hydroxyapatite.

[0047] Specifically, hydroxyapatite (Ca 10 (PO4)6(OH)2) has unique calcium ion channels and surface hydroxyl active sites, allowing for the adsorption / replacement of metal ions through ion exchange. Using a metal catalyst supported on hydroxyapatite as catalyst 6, which has a large specific surface area, can provide abundant active sites to participate in the catalytic reaction, thereby improving the catalytic performance.

[0048] In this embodiment, catalyst 6 is a multi-metal catalyst Cu-Fe-Ni / HAP supported on hydroxyapatite, which further enhances its ozone catalytic performance through the synergistic effect of multiple metals; its preparation method can be carried out by the following steps:

[0049] Carrier pretreatment: HAP particles with a particle size of 20-100 μm were immersed in a 0.1 mol / L Ca(NO3)2 solution and stirred at a constant temperature for 2 h to enhance the surface hydroxyl activity;

[0050] Ion exchange: Selected from copper nitrate, ferric nitrate, and nickel nitrate (Cu). 2+ Fe3 + :Ni 2+ A mixed salt solution was prepared with a molar ratio of 5:5:1 and a total metal ion concentration of 0.05 mol / L. Pretreated HAP was added, and the mixture was stirred and reacted at a constant temperature of 200℃ under reflux for 4 hours.

[0051] Calcination and shaping: After filtration and washing, the product is dried at 105℃ for 12 hours, and then calcined in a muffle furnace at 700℃ for 3 hours with a heating rate of 5℃ / min to form a textured porous structure with pores of 10-50nm on the surface, resulting in a specific surface area of ​​114.2m². 2 / g, pore volume 0.52cm 3 A copper-iron-nickel metal catalyst supported on hydroxyapatite with a loading of 0.5 wt% Cu, 0.5 wt% Fe, and 0.1 wt% Ni.

[0052] Optionally, the reactor 5 is provided with baffles 11 on the inner wall of the catalytic reaction zone, and multiple baffles 11 are evenly distributed along the circumference of the reactor 5.

[0053] Specifically, the baffle 11 causes the fluid inside the reactor 5 to form a turbulent flow state, eliminates dead volume, promotes three-phase turbulence of gas, liquid and solid, and improves the mass transfer coefficient.

[0054] Optionally, the baffle plate 11 is wider at the top and narrower at the bottom, the angle between the inclined side of the baffle plate 11 near the center of the reactor 5 and the horizontal plane is 45°-60°, and the distance between adjacent baffle plates 11 is 200-300mm.

[0055] In this embodiment, as Figure 2 As shown, the baffle 11 is a right-angled triangle that is wider at the top and narrower at the bottom. Four baffles are evenly distributed along the circumference of the inner wall of the reactor 5. The angle between the hypotenuse of the baffle and the horizontal plane is 60°.

[0056] Optionally, an exhaust port is provided at the top of the reactor 5, and the exhaust port is connected to an ozone exhaust gas destroyer 12.

[0057] Specifically, the ozone exhaust gas destroyer 12 is used to purify the residual ozone exhaust gas after the catalytic oxidation reaction in the reactor 5 so that it can be discharged later.

[0058] In this embodiment, the ozone exhaust gas destroyer 12 is a catalytic decomposition ozone destroyer, which is filled with catalyst 6 to reduce the ozone concentration in the exhaust gas to below 0.1 ppm in order to meet emission standards.

[0059] Optionally, a hydrocyclone 13 is connected to the outlet, with a catalyst 6 outlet at the lower end of the hydrocyclone 13 and a liquid phase outlet at the upper end of the hydrocyclone 13.

[0060] Specifically, the cyclone separator 13 can separate the output solid-liquid mixture to achieve efficient separation and recovery of the catalyst 6. The cyclone separator 13 can be a single unit or multiple units can be set as needed. Multiple cyclone separators 13 can be set in parallel to improve separation efficiency.

[0061] Optionally, the outlet is connected to the cyclone separator 13 via the first air-lift device 14.

[0062] Specifically, the reaction products output from the reaction are transported by the first stripping device 14 and fed into the cyclone separator 13 for solid-liquid separation, thereby realizing the recovery of the catalyst 6 and the discharge of the treated liquid.

[0063] Optionally, the outlet of catalyst 6 is connected to reactor 5 via a second stripping device 15.

[0064] Specifically, the recovered catalyst 6 is transported back to the reactor 5 via the second stripping device 15 for reuse, reducing the loss of catalyst 6; this avoids the problems of large footprint and low separation efficiency of traditional precipitation methods, while also avoiding the drawbacks of high investment and operating costs of membrane retention technology.

[0065] In this embodiment, the first air lifting device 14 and the second air lifting device 15 are respectively connected to the first fan 16 and the second fan 17.

[0066] In this embodiment, the upper part of the cyclone separator 13 is a cylindrical structure, and the lower part is a conical structure. A tangential inlet pipe is provided through the upper side wall of the cyclone separator 13. The solid-liquid mixture transported by the first gas-lifting device 14 enters through this pipe. The bottom of the cyclone separator 13 is connected to the second gas-lifting device 15 through the underflow pipe, i.e. the catalyst 6 outlet. The cyclone separator 13 is fixedly connected to the outside of the cyclone separator 13. The fluid enters the cylindrical structure at high speed through the tangential inlet pipe, forming a strong centrifugal force field inside the cylindrical structure. The dense solid catalyst 6 is thrown to the side wall of the separator and flows downward to the sedimentation chamber inside the conical structure. It is then transported back to the reactor 5 by the second gas-lifting device 15. The less dense liquid phase gathers at the center of the conical structure and flows out from the overflow port, i.e. the liquid phase outlet, rotating upward.

[0067] In this embodiment, the second stripping device 15 is connected to the catalyst inlet 10, and the second stripping device 15 inputs the returned catalyst into the catalyst inlet 10.

[0068] In summary, when using the ozone catalytic oxidation system provided by this utility model, taking the treatment of industrial wastewater as an example: the liquid to be treated is in a water tank 8, pump 9 is started to introduce water, and ozone supply device 4 is started at the same time. Ozone is transported through pipelines to microporous aerator head 1 to form submicron-sized ozone bubbles. The water outlet of pump 9 enters Venturi mixer 2, where the high-speed water flow generates negative pressure, drawing in the submicron-sized ozone bubbles and shearing them. Subsequently, the microbubbles generated by Venturi mixer 2 pass through spiral turbulence device 3, where the turbulence effect further refines them. Micro- and nano-sized ozone bubbles with a diameter of no more than 400 nm are introduced into reactor 5. The liquid to be treated, containing these micro- and nano-sized ozone bubbles, is fully mixed in the mixing zone and then enters the catalytic reaction zone, where it fully contacts and reacts with the powdered catalyst 6. The reaction products are then introduced into hydrocyclone 13 via the first stripping device 14. The supernatant is separated by the hydrocyclone 13 and discharged through the liquid phase outlet. The catalyst 6 is separated to the bottom and then transported back to reactor 5 via the second stripping device 15. The residual ozone tail gas generated by reactor 5 is purified by the ozone tail gas destroyer 12 before being discharged.

[0069] More specifically, taking the advanced treatment of a type of chemical wastewater as an example: Influent water quality: COD 450 mg / L, main components are hydroquinone 200 mg / L and oxalic acid 300 mg / L, pH 6.5, water temperature 25℃, influent flow rate 100 m³ / L. 3 / h; During the treatment process, the ozone flow rate is 600m³ / h. 3 The ozone concentration was 150 mg / L, the average particle size of the micro-nano ozone bubbles was 160 nm, the catalyst dosage was 4 g / L, the upward flow rate was 0.8 m / h, the reaction residence time was 30 min, the effluent COD was 42 mg / L, and the removal rate was 90.6%. After 30 days of continuous operation, the removal rates of hydroquinone and oxalic acid were both greater than 95%, the catalyst loss rate was less than 0.1% / month, and the ozone utilization rate was 92%, which is 53% higher than the traditional process. Another example is the biological treatment of petrochemical wastewater: the catalyst dosage was 3 g / L, accounting for 20% of the catalytic reaction zone volume. The COD of the treated liquid before treatment was 200 mg / L. The ozone flow rate was 0.1 L / min, the ozone dosage was 500 mg / L / h, the reaction time was 30 minutes, and the effluent COD was 20 mg / L.

[0070] This ozone catalytic oxidation system uses a microporous aerator 1, a Venturi mixer 2, and a spiral turbulence generator 3 to prepare micro-nano ozone bubbles, which are characterized by small bubble diameter and high stability. The multi-metal catalyst supported on hydroxyapatite effectively solves the problems of low mass transfer efficiency and poor reaction efficiency in fluidized beds. At the same time, a cyclone separator 13 is used to separate the catalyst 6 from the liquid, replacing the traditional precipitation process, which significantly reduces the footprint and improves efficiency. It also overcomes the problems of high investment cost and high operating cost of membrane retention processes.

[0071] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. An ozone catalytic oxidation system, characterized in that, include: A bubble generating device, comprising a microporous aerator, a Venturi mixer, and a spiral turbulence generator connected in sequence, wherein the liquid inlet of the Venturi mixer is used for injecting the liquid to be treated; An ozone supply device, the output of which is sequentially connected to the gas inlet of the microporous aerator and the Venturi mixer; The reactor has an inlet at its lower end, which is connected to the helical turbulence generator. The reactor contains a catalyst, and the reactor has an outlet at its upper end.

2. The ozone catalytic oxidation system according to claim 1, characterized in that, The two ends of the microporous aeration head are respectively connected to the ozone supply device and the Venturi mixer through pipelines, and the pore diameter of the aeration holes of the microporous aeration head is 2-5μm.

3. The ozone catalytic oxidation system according to claim 1, characterized in that, It also includes a water tank for containing the liquid being processed, and a pump connected between the water tank and the liquid inlet of the Venturi mixer.

4. The ozone catalytic oxidation system according to claim 1, characterized in that, The reactor is provided with a mixing zone and a catalytic reaction zone arranged from bottom to top. The mixing zone is connected to the catalytic reaction zone, and the catalytic reaction zone is provided with a catalyst inlet.

5. The ozone catalytic oxidation system according to claim 4, characterized in that, The catalyst is a metal catalyst supported on hydroxyapatite.

6. The ozone catalytic oxidation system according to claim 5, characterized in that, The reactor is provided with baffles on the inner wall of the catalytic reaction zone, and a plurality of baffles are evenly distributed along the circumference of the reactor.

7. The ozone catalytic oxidation system according to claim 1, characterized in that, The reactor is equipped with an exhaust port at the top, and the exhaust port is connected to an ozone exhaust gas destroyer.

8. The ozone catalytic oxidation system according to claim 1, characterized in that, The outlet is connected to a hydrocyclone separator, the lower end of which is provided with a catalyst outlet, and the upper end of which is provided with a liquid phase outlet.

9. The ozone catalytic oxidation system according to claim 8, characterized in that, The outlet is connected to the cyclone separator via a first air-lift device.

10. The ozone catalytic oxidation system according to claim 8, characterized in that, The catalyst outlet is connected to the reactor via a second stripping device.

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