Photocatalytic reactor and wastewater treatment device

Abstract

The utility model relates to a photocatalytic reactor and a wastewater treatment device, the photocatalytic reactor is used for wastewater treatment, the photocatalytic reactor comprises: a housing, the housing is provided with a water inlet, a water outlet and a catalyst inlet, the water inlet is arranged below the water outlet, the catalyst inlet is used for introducing a heterogeneous catalyst, and the catalyst inlet is arranged below the water outlet; an ultraviolet light source and an overflow screen plate are arranged in the shell, and the overflow screen plate is used for limiting the heterogeneous catalyst from flowing out. The photocatalytic reactor is high in photocatalytic degradation efficiency and can avoid loss of a heterogeneous catalyst so as to at least partially solve the problems in related technologies.

Description

Technical Field

[0001] The present disclosure relates to the technical field of wastewater treatment, and in particular, to a photocatalytic reactor and a wastewater treatment device. Background Art

[0002] Currently, conventional physicochemical and biochemical treatment methods have limited capacity for treating refractory organic wastewater. Therefore, advanced oxidation processes are often employed for deep treatment. These processes utilize strong oxidizing free radicals (such as ·OH) to directly mineralize organic matter into carbon dioxide and water, or to convert refractory organic matter into readily biodegradable small molecules that facilitate subsequent coupled biochemical treatment. Ultraviolet (UV) advanced oxidation technology utilizes irradiation of different UV wavelengths, combined with various homogeneous and heterogeneous catalysts, to degrade or cleave organic matter through direct and indirect photolysis. Direct photolysis involves the direct absorption of UV radiation energy by pollutants, leading to bond cleavage; indirect photolysis involves the absorption of UV radiation by homogeneous or heterogeneous catalysts, generating strong oxidizing free radicals that react with organic matter to degrade it. This technology offers strong oxidizing power, relatively mild reaction conditions, and a simple process, making it suitable for the advanced treatment of refractory wastewater with low COD and low turbidity.

[0003] In the related art, there are problems in the wastewater treatment process such as low efficiency of photocatalytic degradation of pollutants and easy loss of heterogeneous catalysts. Utility Model Content

[0004] The purpose of the present disclosure is to provide a photocatalytic reactor and a wastewater treatment device for wastewater treatment, wherein the photocatalytic reactor has high photocatalytic degradation efficiency and can avoid loss of heterogeneous catalysts, so as to at least partially solve the problems in the related art.

[0005] In order to achieve the above-mentioned objectives, the first aspect of the present disclosure provides a photocatalytic reactor for wastewater treatment, comprising: a shell, wherein the shell is provided with a water inlet, a water outlet and a catalyst inlet, the water inlet is arranged below the water outlet, the catalyst inlet is used to introduce a heterogeneous catalyst, and an ultraviolet light source and an overflow mesh plate are provided in the shell, and the overflow mesh plate is used to limit the outflow of the heterogeneous catalyst.

[0006] Optionally, the overflow mesh plate includes an overflow plate and a filter screen, the overflow plate and the inner wall of the shell form an overflow groove, the water outlet is connected to the overflow groove, the upper end of the overflow plate is higher than the water outlet, and the filter screen is arranged at the upper end of the overflow plate.

[0007] Optionally, an expanded diameter section is provided on the shell and close to the water outlet.

[0008] Optionally, an included angle between the tube wall of the expanded diameter section and the central axis of the shell in the vertical direction is 35° to 45°.

[0009] Optionally, the ultraviolet light source includes a plurality of ultraviolet lamp tubes, and the plurality of ultraviolet lamp tubes are arranged at intervals along the circumference of the central axis of the shell.

[0010] Optionally, the ultraviolet lamp tube extends from the water inlet toward the water outlet, and the top end of the ultraviolet lamp tube is located above the water outlet.

[0011] Optionally, a water distributor is provided in the shell, the water distributor is located above the water inlet, and a mounting groove for mounting the ultraviolet lamp is provided on the water distributor; and each ultraviolet lamp is provided with a sleeve.

[0012] Optionally, the shell is further provided with an aeration plate, which is arranged above the water distributor, and the top of the shell is provided with an exhaust port.

[0013] Optionally, the shell further includes a catalyst discharge port, which is arranged in the shell and located on one side of the water distributor; and / or a drain outlet is provided at the bottom end of the shell; and / or the photocatalytic reactor further includes an observation window, which is arranged between the water inlet and the water outlet.

[0014] A second aspect of the present disclosure provides a wastewater treatment device, comprising the above-mentioned photocatalytic reactor.

[0015] Optionally, the wastewater treatment device includes a mixer, which is connected to the water inlet and is used to mix the wastewater, oxidant and homogeneous catalyst and send the mixed liquid into the photocatalytic reactor.

[0016] Optionally, the wastewater treatment device also includes a sensor and a controller, the controller is electrically connected to the sensor and the ultraviolet light source, the sensor is used to measure the COD value of the wastewater before entering the mixer, and the controller is used to selectively turn on the number of ultraviolet lamps in the ultraviolet light source according to the COD value measured by the sensor.

[0017] Optionally, the wastewater treatment device further includes a buffer tank communicated with the water outlet, and a circulation pump and a liquid outlet pump connected to the buffer tank, and the outlet of the circulation pump is communicated with the water inlet.

[0018] Through the above technical solution, a heterogeneous catalyst is introduced through the catalyst inlet in the shell, and the ultraviolet light source arranged in the shell can photocatalyze the heterogeneous catalyst to degrade the pollutants in the wastewater entering the shell. At the same time, the overflow mesh plate is higher than the water outlet, so that the overflow mesh plate can limit the outflow of the heterogeneous catalyst from the water outlet, so that the photocatalytic degradation efficiency of the photocatalytic reactor is high and the loss of the heterogeneous catalyst can be avoided.

[0019] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0021] Figure 1 is a schematic structural diagram of a photocatalytic reactor provided in an exemplary embodiment of the present disclosure;

[0022] Figure 2 yes Figure 1 AA-direction cross-sectional view;

[0023] Figure 3 yes Figure 1 BB-direction cross-sectional view;

[0024] Figure 4 Schematic diagram of a wastewater treatment process according to an exemplary embodiment of the present disclosure.

[0025] Description of Reference Numerals

[0026] 1-shell; 11-water inlet; 12-water outlet; 13-catalyst inlet; 14-expanded diameter section; 15-exhaust port; 16-catalyst outlet; 17-drain outlet; 18-observation window; 2-ultraviolet light source; 21-ultraviolet lamp; 3-overflow screen; 31-overflow plate; 32-filter; 33-overflow trough; 4-water distributor; 5-aeration plate; 51-inlet pipe; 6-mixer; 7-sensor; 8-controller; 9-buffer tank; 91-circulation pump; 92-liquid outlet pump. DETAILED DESCRIPTION

[0027] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0028] In this disclosure, unless otherwise stated, directional words such as "upper" and "lower" may be used to refer to Figure 1 In the directions indicated by the upper and lower arrows, "inside" and "outside" refer to the outline of the component itself. It should be noted that the terms "first" and "second" are used to distinguish one element from another and do not imply order or importance. In the description with reference to the accompanying drawings, the same reference numerals in different drawings represent the same element.

[0029] like Figure 1-Figure 4As shown, the first aspect of the present disclosure provides a photocatalytic reactor for wastewater treatment, comprising: a shell 1, a water inlet 11, a water outlet 12 and a catalyst inlet 13 are provided on the shell 1, the water inlet 11 is arranged below the water outlet 12, the catalyst inlet 13 is used to introduce a heterogeneous catalyst, an ultraviolet light source 2 and an overflow screen 3 are provided in the shell 1, the overflow screen 3 is arranged adjacent to the water outlet 12 and at least part of the overflow screen 3 is higher than the water outlet 12, and the overflow screen 3 is used to limit the outflow of the heterogeneous catalyst.

[0030] Through the above technical solution, a heterogeneous catalyst is introduced through the catalyst inlet 13 in the shell 1, and the ultraviolet light source 2 arranged in the shell 1 can photocatalyze the heterogeneous catalyst to degrade the pollutants in the wastewater entering the shell 1. At the same time, the overflow mesh plate 3 is higher than the water outlet 12, so that the overflow mesh plate 3 can limit the flow of the heterogeneous catalyst from the water outlet 12, so that the photocatalytic degradation efficiency of the photocatalytic reactor is high and the loss of the heterogeneous catalyst can be avoided.

[0031] Among them, the heterogeneous catalyst of the photocatalytic reactor is a spherical catalyst loaded with TiO2 or ZnO2 active components, with a particle size of 0.5~2 mm and a bulk density of 0.5~3 g / mL.

[0032] In some feasible embodiments, in order to prolong the contact time of the heterogeneous catalyst with the ultraviolet light source 2 and the wastewater and avoid the loss of the heterogeneous catalyst, the overflow screen 3 includes an overflow plate 31 and a filter screen 32. The overflow plate 31 and the inner wall of the shell 1 form an overflow groove 33. The overflow groove 33 is connected to the water outlet 12. The upper end of the overflow plate 31 is higher than the water outlet 12. The filter screen 32 is arranged at the upper end of the overflow plate 31.

[0033] Specifically, the overflow plate 31 may include a first arc segment and a second arc segment, the first arc segment extends toward the inside of the shell 1 and the outer edge of the first arc segment is welded to the inner wall of the shell 1, the second arc segment is formed on the inner edge of the first arc segment and extends in the vertical direction, the first arc segment and the second arc segment are formed as one piece, the first arc segment, the second arc segment and the inner wall of the shell 1 together form an overflow groove 33, the upper end of the second arc segment is higher than the water outlet 12, and the filter 32 is arranged at the upper end of the second arc segment, so that the wastewater in the shell 1 can undergo a photocatalytic reaction with the heterogeneous catalyst under the irradiation of the ultraviolet light source 2. By setting the first arc segment and the second arc segment, the contact time of the heterogeneous catalyst with the ultraviolet light source 2 and the wastewater is extended, and at the same time, the loss of the heterogeneous catalyst can be prevented by the filter.

[0034] In order to facilitate the recovery of the heterogeneous catalyst and extend the contact time between the heterogeneous catalyst and the ultraviolet light source 2 and the wastewater, in some practicable embodiments, an expanded diameter section 14 is provided on the shell 1 near the water outlet 12. Specifically, the angle between the tube wall of the expanded diameter section 14 and the central axis of the shell 1 in the vertical direction is 35° to 45°. For example, the shell 1 is cylindrical, the angle between the tube wall of the expanded diameter section 14 and the central axis of the shell 1 in the vertical direction can be 41°, and the ratio of the maximum diameter to the minimum diameter of the expanded diameter section 14 is 1.5 to 2.0. In this way, the provision of the expanded diameter section 14 can enable the wastewater to form a fluidized reaction state within the shell 1 and below the expanded diameter section 14, thereby extending the residence time of the wastewater in the shell 1 to 10 to 30 minutes, which can fully degrade the wastewater. In addition, the provision of the expanded diameter section 14 can also reduce the flow rate of the mixed liquid, facilitate the sinking of the heterogeneous catalyst, and facilitate the recovery of the heterogeneous catalyst.

[0035] In some embodiments, the ultraviolet light source 2 includes a plurality of ultraviolet lamps 21, which are arranged at intervals along the circumference of the central axis of the housing 1. The upper ends of the ultraviolet lamps 21 are electrically connected to an external power source, and dual-band ultraviolet lamps of 254 nm and 185 nm can be used. After an oxidant is injected into the housing 1, the 254 nm ultraviolet light interacts with the oxidant to produce strongly oxidizing free radicals, which then react with organic matter to achieve degradation. Vacuum ultraviolet light with a wavelength of 185 nm can combine with oxygen molecules in the air or water to produce ozone, which has strong oxidizing properties. The power of a single ultraviolet lamp is 325 W. The number of ultraviolet lamps 21 in the reactor can be eight, and the eight ultraviolet lamps 21 are arranged at equal intervals along the central axis of the housing 1, thereby enabling the wastewater in the housing 1 to be fully irradiated with ultraviolet light to improve the efficiency of photocatalytic degradation.

[0036] It is understandable that the number of eight ultraviolet lamps 21 is merely illustrative, and in other embodiments, the number may be other, which is not limited in the present disclosure.

[0037] To improve the photocatalytic efficiency, in some embodiments, the UV lamp 21 extends from the water inlet 11 toward the water outlet 12, with the top of the UV lamp 21 located above the water outlet 12. This ensures that the UV lamp 21 is sufficiently long within the housing 1, allowing the wastewater and the heterogeneous catalyst to be continuously irradiated by the UV lamp 21 as the water level of the wastewater within the housing 1 rises. This allows the wastewater within the housing 1 to be fully irradiated by UV light, thereby improving the photocatalytic degradation efficiency.

[0038] Optionally, a water distributor 4 is provided in the shell 1. The water distributor 4 is a ring plate with multiple through holes. The water distributor 4 is located above the water inlet 11. The water distributor 4 is provided with a mounting groove for installing the ultraviolet lamp tube 21, so that the lower end of the ultraviolet lamp tube 21 can be easily fixed. In order to facilitate the protection of the ultraviolet lamp tube 21 and the installation of the ultraviolet lamp tube 21, in some feasible methods, each ultraviolet lamp tube 21 is provided with a sleeve, which can be transparent quartz glass, and the installation groove can be a spring protection groove, so that the spring arranged in the installation groove can provide upward elastic force, so that the ultraviolet lamp tube 21 can be installed more securely and stably.

[0039] In order to facilitate the full contact between the wastewater and the heterogeneous catalyst under the irradiation of the ultraviolet lamp, the shell 1 is further provided with an aeration plate 5, which is arranged above the water distributor 4. The top of the shell 1 is provided with an exhaust port 15, and the aeration plate 5 is provided with an air inlet pipe 51. For example, the aeration plate 5 of the photocatalytic reactor is made of titanium alloy, the diameter of the aeration plate is 150mm, the diameter of the aeration bubble is 0.1~2mm, and the gas can be air, oxygen, or ozone; the wastewater volume flow rate is 0.2~1.0m 3 / h, and the gas-liquid volume flow ratio is controlled to be 4:1 to 1:1. The provision of the aeration disk 5 enables a more uniform distribution of the catalyst in the photocatalytic reactor. Under ultraviolet irradiation, the wastewater to be treated undergoes a photocatalytic reaction in the presence of the catalyst, thereby effectively removing pollutants in the wastewater.

[0040] In order to facilitate the removal of the intercepted heterogeneous catalyst, in some feasible embodiments, the shell 1 also includes a catalyst discharge port 16, which is arranged in the shell 1 and located on one side of the water distributor 4, so that when the catalytic reaction is completed, the waste water can be discharged through the drain port 17 at the bottom end of the shell 1 and the corresponding heterogeneous catalyst can be taken out by opening the catalyst discharge port 16.

[0041] To facilitate observation of the photocatalytic reaction, in some embodiments, the photocatalytic reactor further includes an observation window 18, which is disposed between the water inlet 11 and the water outlet 12. For example, two observation windows 18 are provided, one above the aeration disk 5 and one below the expanded diameter section 14, respectively, to facilitate observation of the photocatalytic reaction within the housing 1.

[0042] A second aspect of the present disclosure provides a wastewater treatment device comprising the above-mentioned photocatalytic reactor. By installing the photocatalytic reactor in the wastewater treatment device, the photocatalytic degradation efficiency can be improved, the loss of heterogeneous catalysts can be avoided, and the cost can be reduced.

[0043] In some practicable embodiments, the wastewater treatment device includes a mixer 6, which is connected to the water inlet 11. The mixer 6 is used to mix wastewater, an oxidant, and a homogeneous catalyst and send the mixed liquid to a photocatalytic reactor. The oxidant can be one or more of hydrogen peroxide, sodium hypochlorite, and persulfate; the homogeneous catalyst can be one or more of ferrous sulfate solution, copper sulfate solution, ferric chloride solution, and manganese nitrate solution; and the heterogeneous catalyst is a spherical catalyst loaded with TiO2 or ZnO2 active components, with a particle size of 0.5 to 2 mm and a bulk density of 0.5 to 3 g / mL. Thus, by setting up the mixer 6, the wastewater can be pre-treated with the oxidant and the homogeneous catalyst first, and then after entering the housing 1, it is further degraded by ultraviolet light and catalysis by the heterogeneous catalyst.

[0044] In some embodiments, the wastewater treatment device further includes a sensor 7 and a controller 8. The controller 8 is electrically connected to the sensor 7 and the ultraviolet light source 2. The sensor 7 is used to measure the COD value of the wastewater before it enters the mixer 6. The controller 8 is used to selectively turn on the number of ultraviolet lamps 21 in the ultraviolet light source 2 based on the COD value measured by the sensor 7. For example, the sensor 7 can perform an online test on the COD value of the wastewater. When the COD is greater than 150 mg / L and less than or equal to 200 mg / L, the ultraviolet lamps are fully turned on; when the COD is greater than 100 mg / L and less than or equal to 150 mg / L, three-quarters of the ultraviolet lamps are turned on; when the COD is greater than 50 mg / L and less than or equal to 100 mg / L, half of the ultraviolet lamps are turned on; and when the COD is less than 50 mg / L, one-quarter of the ultraviolet lamps are turned on. Preferably, the wastewater has a COD of 200 mg / L or less, a biodegradability ratio (BOD / COD) of 0.2 or less, a turbidity of 10 NTU or less, a conductivity of 5 mS / cm or less, and a calcium-magnesium hardness of 300 mg / L or less. Consequently, the controller 8 can precisely control the number of UV lamps 21 activated based on the COD value from the sensor 7, reducing costs. It is understood that the controller 8 can be a single-chip microcomputer, a PLC controller, or the control center of the wastewater treatment device. The controller 8 can be electrically connected to the sensor 7 and the UV lamps 21 via wired or wireless communication.

[0045] Optionally, the wastewater treatment device also includes a buffer tank 9 connected to the water outlet 12, and a circulating pump 91 and a liquid outlet pump 92 connected to the buffer tank 9. The outlet of the circulating pump 91 is connected to the water inlet 11. The treated water can be discharged through the liquid outlet pump 92. The treated water can be re-entered into the shell 1 through the setting of the circulating pump 91. The fluidization of the heterogeneous catalyst is achieved through the circulating pump, thereby improving the photocatalytic efficiency and further degrading the pollutants in the wastewater.

[0046] During the working process, the spherical catalyst is added to the photocatalytic reactor through the catalyst inlet, and then the wastewater to be treated and the oxidant are mixed in the mixer by using the water inlet pump and the oxidant pump and enter the wastewater inlet 11. The fluidization of the heterogeneous catalyst is achieved through the air inlet pipe 51, the aeration plate 5 and the circulation pump 91; the ultraviolet lamp 21 is turned on by the sensor and the controller, and the reactor expansion section 14 and the overflow screen 3 are used to separate the treated wastewater from the heterogeneous catalyst; after the wastewater treatment is completed, the ultraviolet lamp 21 and the air inlet pipe 51 are turned off, the water is drained through the wastewater outlet 17, and then the heterogeneous catalyst is recovered and reused through the catalyst outlet.

[0047] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0048] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0049] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A photocatalytic reactor for wastewater treatment, characterized in that: The invention comprises a shell, wherein the shell is provided with a water inlet, a water outlet and a catalyst inlet, wherein the water inlet is provided below the water outlet, the catalyst inlet is used for introducing a heterogeneous catalyst, and an ultraviolet light source and an overflow screen are provided in the shell, wherein the overflow screen is used for limiting the outflow of the heterogeneous catalyst.

2. The photocatalytic reactor according to claim 1, characterized in that: The overflow screen includes an overflow plate and a filter screen. The overflow plate and the inner side wall of the shell form an overflow groove. The water outlet is connected to the overflow groove. The upper end of the overflow plate is higher than the water outlet. The filter screen is arranged at the upper end of the overflow plate.

3. The photocatalytic reactor according to claim 1, characterized in that An expanded diameter section is provided on the shell body near the water outlet.

4. The photocatalytic reactor according to claim 3, characterized in that: The included angle between the tube wall of the expanded diameter section and the central axis of the shell in the vertical direction is 35° to 45°.

5. The photocatalytic reactor according to claim 1, characterized in that: The ultraviolet light source includes a plurality of ultraviolet lamp tubes, and the plurality of ultraviolet lamp tubes are arranged at intervals along the circumference of the central axis of the shell.

6. The photocatalytic reactor according to claim 5, characterized in that: The ultraviolet lamp tube extends from the water inlet toward the water outlet, and the top end of the ultraviolet lamp tube is located above the water outlet.

7. The photocatalytic reactor according to claim 5, characterized in that: A water distributor is provided in the housing, the water distributor is located above the water inlet, and the water distributor is provided with a mounting groove for mounting the ultraviolet lamp; and Each of the ultraviolet lamp tubes is sleeved with a sleeve.

8. The photocatalytic reactor according to claim 7, characterized in that: The shell is further provided with an aeration plate, which is arranged above the water distributor, and the top of the shell is provided with an exhaust port.

9. The photocatalytic reactor according to claim 7, characterized in that: The shell further comprises a catalyst discharge port, which is arranged in the shell and located on one side of the water distributor; and / or The bottom end of the shell is provided with a drain outlet; and / or The photocatalytic reactor further includes an observation window, which is arranged between the water inlet and the water outlet.

10. A wastewater treatment device, characterized in that: The invention comprises the photocatalytic reactor according to any one of claims 1 to 9.

11. The wastewater treatment device according to claim 10, characterized in that: The wastewater treatment device comprises a mixer, which is communicated with the water inlet and is used for mixing wastewater, an oxidant and a homogeneous catalyst and sending the mixed liquid into the photocatalytic reactor.

12. The wastewater treatment device according to claim 11, characterized in that The wastewater treatment device also includes a sensor and a controller, which is electrically connected to the sensor and the ultraviolet light source. The sensor is used to measure the COD value of the wastewater before entering the mixer, and the controller is used to selectively turn on the number of ultraviolet lamps in the ultraviolet light source according to the COD value measured by the sensor.

13. The wastewater treatment device according to claim 10, characterized in that: The wastewater treatment device further includes a buffer tank communicated with the water outlet, and a circulation pump and a liquid outlet pump connected to the buffer tank, wherein the outlet of the circulation pump is communicated with the water inlet.

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