A continuous flow photocatalytic reaction device for degrading SDBS and a control method thereof

Abstract

A kind of continuous flow photocatalytic reaction device and control method for degrading SDBS belong to wastewater treatment technical field.The device includes water flow direction in order to set water inlet module, photocatalytic module, sedimentation module, between by conveying pipeline connection, after the water flow of sedimentation module is backflowed to water inlet module by circulation pipeline, conveying pump is arranged on conveying pipeline between water inlet module and photocatalytic module, circulation pump is arranged on circulation pipeline, each module machine each pump is connected control cabinet;Mixed solution of built-in catalyst in water inlet module and SDBS wastewater;Photocatalytic module includes reactor, light shield, catalyst reaction tube and light assembly, light shield is sleeved on the outer periphery of reactor, on the opposite side wall of light shield, air inlet pipe and exhaust pipe close to the two ends of reactor are connected respectively, exhaust fan is arranged on exhaust pipe.The application makes SDBS wastewater continuous flow, catalyst can be recycled, can adapt to different concentration SDBS wastewater treatment.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and in particular relates to a continuous flow photocatalytic reaction device and control method for degrading SDBS. Background Technology

[0002] Sodium dodecylbenzene sulfonate (SDBS) is a typical anionic surfactant widely used in industries such as electroplating, detergents, textiles, printing and dyeing, and leather. Its molecular structure contains hydrophobic alkylbenzene chains and hydrophilic sulfonic acid groups. This amphiphilic nature allows SDBS to easily form micelles in water, exhibiting excellent detergency, foaming, and emulsifying properties. However, this also leads to unique challenges in environmental treatment. The benzene rings in the SDBS molecular structure make it difficult to rapidly and completely degrade using traditional biological methods, allowing it to persist in the environment and exert toxicity on aquatic organisms. The foam it forms can also cover the water surface, affecting water reoxygenation and ecological health. In wastewater treatment, the surface activity of SDBS significantly alters the solid-liquid interface properties, easily leading to excessive foaming in aeration systems, severe fouling and clogging of membrane treatment processes, and affecting flocculation and sedimentation effects.

[0003] Photocatalytic oxidation, as an advanced oxidation technology, has been widely used in wastewater treatment in recent years due to its green and efficient characteristics. Photocatalytic oxidation involves a catalyst generating active groups under light irradiation, which then come into contact with the target pollutants to undergo a redox reaction, efficiently degrading or even mineralizing the pollutants into non-toxic and harmless small molecules. Currently, most photocatalytic experiments employ a batch process, placing the water sample and catalyst in a closed system for treatment. While this method provides precise experimental conditions and data, it suffers from problems in practical applications, such as unstable reaction conditions, low treatment efficiency, and difficulty in adapting to large-scale industrial needs.

[0004] To address the aforementioned issues, continuous flow photocatalytic reactors have gradually become a research focus. Continuous flow reactors offer advantages such as large processing capacity, ease of operation, and controllable reaction conditions. However, existing continuous flow photocatalytic reactors still suffer from several key bottlenecks in design and operation, hindering their efficient and stable application in practical SDBS wastewater treatment. On one hand, insufficient heat dissipation of the light source within the reactor often leads to accelerated thermal decay and shortened lifespan. On the other hand, commonly used suspended TiO2-based catalysts are easily lost with the effluent in continuous flow systems, increasing catalyst consumption costs and affecting the continuous stability of treatment. Furthermore, most existing systems lack real-time monitoring and adaptive adjustment capabilities for key indicators such as water quality parameters, temperature, and catalyst concentration, resulting in significant fluctuations in operational efficiency and treatment effects. These shortcomings collectively limit the large-scale application and reliability of continuous flow photocatalytic technology in the degradation of SDBS wastewater. Summary of the Invention

[0005] To address the aforementioned technical problems and to solve the issues of incomplete degradation, unstable operation, and high energy consumption in traditional SDBS treatment, this invention provides a continuous flow photocatalytic reaction device and control method for degrading SDBS. This method can improve the contact efficiency between the photocatalyst and the pollutants, enhance light utilization, and thus improve the efficiency of the photocatalytic reaction, which has significant practical implications.

[0006] The objective of this invention is achieved through the following technical solution: This invention discloses a continuous flow photocatalytic reaction device for degrading SDBS. The device comprises an inlet module, a photocatalytic module, and a precipitation module arranged sequentially in the direction of water flow, connected by a transport pipeline. Water precipitated in the precipitation module flows back to the inlet module via a circulation pipeline. A transport pump is installed on the transport pipeline between the inlet module and the photocatalytic module, and a circulation pump is installed on the circulation pipeline. All components—the inlet module, photocatalytic module, precipitation module, transport pump, and circulation pump—are connected to a control cabinet to control the operation of each module and pump. The inlet module contains a mixture of catalyst and SDBS wastewater. The photocatalytic module includes a reactor, a light shield, a catalyst reaction tube located at the center of the reactor, and a light-emitting assembly parallel to the axis of the catalyst reaction tube and evenly distributed in a ring around it. Both ends of the catalyst reaction tube extend beyond the reactor mounting plate and connect to the transport pipeline. The light shield is fitted around the outer perimeter of the reactor. An air inlet pipe and an air outlet pipe are connected to opposite side walls of the light shield, respectively, and are located near the two ends of the reactor. An exhaust fan is installed on the exhaust pipe.

[0007] Furthermore, each of the catalyst reaction tubes extending from the mounting plates at both ends of the reactor is equipped with a safety isolation solenoid valve I. The safety isolation solenoid valve I is connected to the control cabinet. The safety isolation solenoid valve I remains open throughout the operation of the entire device. When the control cabinet receives an abnormal signal or when maintenance of the entire device is required, the safety isolation solenoid valves I at both ends are automatically closed to isolate the reactor from the entire device.

[0008] Furthermore, the illumination component includes an ultraviolet light-emitting diode and a reflector tube sleeved outside the ultraviolet light-emitting diode. The wavelength of the ultraviolet light-emitting diode is 365 nm. The catalyst reaction tube is made of quartz glass, which is transparent. Temperature sensors are installed on the outer walls of both ends of the catalyst reaction tube placed inside the reactor. The temperature sensors are connected to the control cabinet via signals.

[0009] Furthermore, the photocatalytic module is equipped with a light shield that is fitted around the outer periphery of the reactor and coated with a reflective coating on the inner wall. The two mounting plates of the reactor are coated with a reflective coating on the inner side of the reactor. The catalyst in the catalyst reaction tube is a titanium dioxide-based photocatalyst.

[0010] Furthermore, the sedimentation module includes a sedimentation tank with a conical bottom and a conical slope ranging from 45° to 60°. The bottom outlet of the conical structure is connected to a return pipe. An inlet pipe II and an outlet pipe II are staggered on opposite sidewalls of the sedimentation tank. A flushing pipe with one end extending into the sedimentation tank is installed at the bottom of the sedimentation tank. Multiple nozzles spraying towards the conical surface are provided on the flushing pipe located inside the sedimentation tank. A mud level gauge is installed on the middle sidewall of the sedimentation tank.

[0011] Furthermore, the outlet pipe II is equipped with an outlet solenoid valve connected to the control cabinet. The outlet solenoid valve is normally in the open state to ensure that the qualified outlet water is discharged normally. When the outlet water does not meet the standards and needs to be returned for treatment, the outlet solenoid valve is closed, so that the unqualified wastewater returns to the inlet module through the circulation pipeline for photocatalytic degradation again.

[0012] Furthermore, the flushing pipe is connected to an external water source and is equipped with a solenoid valve connected to a control cabinet to control the external water source to enter the flushing pipe to flush the sedimentation tank.

[0013] Furthermore, the water inlet module includes a water inlet tank and a cover plate for sealing the upper port of the water inlet tank. A stirring paddle with its stirring end inside the water inlet tank is installed on the cover plate for preliminary mixing of the catalyst and SDBS wastewater. A water outlet pipe I is provided at the bottom of the water inlet tank, and the water outlet pipe I is connected to the catalyst reaction tube of the photocatalytic module through a delivery pipeline. A return pipe and the water inlet pipe I are provided on the side wall near the top of the water inlet tank. An online SDBS concentration sensor is installed on the water inlet pipe I of the water inlet tank, and a level gauge is installed inside the water inlet tank. Both the online SDBS concentration sensor and the level gauge are connected to the control cabinet.

[0014] The control method for the aforementioned reaction apparatus includes: SDBS wastewater and titanium dioxide-based catalyst were continuously added to the inlet tank, and the agitator was started to continuously mix them at a speed of 120 r / min to form a uniform mixture. Adjust the parameters of the central control cabinet and preset the flow rate of the delivery pump to keep the hydraulic residence time of wastewater in the reactor stable at 30 to 60 minutes to ensure the full degradation of SDBS. The delivery pump is started to continuously deliver the mixture to the catalyst reaction tube at a set flow rate. During the continuous flow, the mixture is irradiated by ultraviolet light from the light-emitting components, resulting in a photocatalytic degradation reaction. The level gauge monitors the water level in the inlet tank in real time and sends feedback to the control cabinet. When the water level is below 20%, the control cabinet issues a low-level alarm, prompting the replenishment of the mixture. When the water level is below 10%, the control cabinet automatically stops the delivery pump and shuts down the light-emitting components, while simultaneously issuing a critical alarm. The system resets and restarts after the water level rises above 20%. The SDBS concentration online sensor on inlet pipe I feeds the signal back to the control cabinet. The ultraviolet light intensity is adjusted according to the SDBS concentration: when the concentration is higher than 100 mg / L, the light intensity is 100%; when the concentration is 50-100 mg / L, the light intensity is 70%; when the concentration is lower than 50 mg / L, the light intensity is 50%. The light module is linked to the delivery pump. After the delivery pump starts, the light module will automatically turn on after a delay of 5-10 seconds; when the delivery pump stops, the light module will immediately turn off. Temperature sensors monitor the temperature in the reactor in real time and feed it back to the control cabinet: when the temperature is above 30 ℃, the exhaust fan starts and speeds up as the temperature rises; when the temperature is between 40 ℃ and 45 ℃, the exhaust fan speeds up to the maximum safe speed, and the power of the light source in the lighting component is reduced to 80% of the rated value; if the temperature is above 45 ℃, the power of the light source is further reduced to 50% of the rated value, and the exhaust fan maintains the maximum safe speed; if the temperature continues to rise to 50 ℃, the power supply to the light source is automatically cut off, and the system is manually reset after the temperature drops back to the safe threshold. After the mixture reacts, it enters a settling tank for sedimentation. When the catalyst deposition thickness exceeds 10 cm as detected by the mud level gauge, the control cabinet automatically triggers the backwashing and catalyst recovery program: the solenoid valve on the flushing pipeline is opened, the nozzle flushes for 60 seconds, stops for 30 seconds, and repeats the cycle 3 times to disperse and resuspend the deposited catalyst; after flushing, the circulation pump on the circulation pipeline is automatically started and runs for 5 minutes to send the catalyst slurry that has been flushed and resuspended in the settling tank back to the inlet tank. The frequency of the circulation pump is adjusted according to the liquid level in the settling tank. When the liquid level is higher than 50% of the effective height of the tank, the circulation pump runs at full speed at the rated speed; when the liquid level is in the range of 30% to 50%, the frequency gradually decreases to 50% to 60% of the rated speed; when the liquid level is lower than 30%, the frequency decreases to 20% to 30% of the rated speed; when the liquid level is lower than 10%, the circulation pump is immediately stopped and a low-level alarm is triggered.

[0015] Furthermore, the SDBS concentration in the supernatant of the settling tank is checked every 2 hours; if it does not meet the standard, one or more of the following measures are manually triggered: ① Increase light intensity: Increase the light intensity by 5%~10% each time, run it stably for 30 minutes after adjustment and retest. Repeat the above steps until the light intensity reaches the rated maximum value; ② Extend the hydraulic residence time: Each time the adjustment is made, the frequency of the delivery pump is reduced to decrease the inlet flow rate by 10% to 20%, and the hydraulic residence time is extended accordingly to 1.1 to 1.25 times the original value; if the adjustment is made multiple times, the cumulative extended hydraulic residence time shall not exceed twice the original value. ③ Recirculation treatment: Part of the substandard effluent is returned to the inlet tank for further treatment through the circulation pipeline, and the recirculation ratio is controlled at 10%~80%.

[0016] The beneficial effects of this invention are as follows: 1. This invention connects the influent module, photocatalytic module, and precipitation module into a closed-loop system through conveying pipelines and circulation pipelines, so that SDBS wastewater keeps flowing continuously in the circulation system and the catalyst can be recycled; the operation of each module and pump is controlled by a control cabinet to adapt to the treatment needs of SDBS wastewater of different concentrations.

[0017] 2. The photocatalytic module of this invention employs a photoreactor with a built-in exhaust fan to ensure stable operation of the light source over long periods and maintain uniform temperature in the reaction system, preventing catalyst deactivation. After the reactor effluent enters the sedimentation tank, the photocatalyst naturally settles and accumulates at the bottom. The supernatant is discharged or recirculated, and the settled catalyst is returned to the inlet tank through a circulation pipeline, thus preventing catalyst loss and enabling reuse. Furthermore, the device is equipped with a control cabinet that can adjust key operating parameters such as inlet flow rate, light source intensity, and reaction temperature in real time to meet the treatment needs of SDBS wastewater with different concentrations.

[0018] 3. The present invention incorporates a reflector tube within the illumination component and mounts coated with a reflective coating and a light shield at both ends and the periphery of the reactor. This allows ultraviolet light to be uniformly scattered to the central area of ​​the reaction tube, ensuring uniform illumination of the catalyst and improving the degradation efficiency of pollutants. Simultaneously, the exhaust fan installed on the reactor is connected to the interior of the reactor, which can effectively reduce the operating temperature of the module and prevent the ultraviolet light source from attenuating or being damaged due to overheating, thereby extending the lifespan of the light source and maintaining the efficient and stable photocatalytic reaction.

[0019] 4. The sedimentation module of this invention has a flushing pipe and nozzle at the bottom of the sedimentation tank, which can periodically flush the deposited catalyst, resuspend it, and return it to the inlet tank via the circulation pipe to participate in the reaction again. This design not only achieves continuity of the treatment process, but also significantly reduces catalyst consumption, lowers operating costs, and improves overall treatment efficiency and system stability.

[0020] 5. The control method of the present invention is based on the above-mentioned device. By optimizing the coordinated operation of each module, it achieves accurate control of reaction conditions and intensification of the process. The device has a compact structure and flexible operation, and can significantly improve light energy utilization and mass transfer efficiency, thereby achieving efficient, stable, and low-consumption degradation of SDBS, providing a reliable technical solution for the deep treatment of wastewater containing recalcitrant surfactants. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the overall process flow of the present invention.

[0022] Figure 2 This is a structural diagram of the water inlet module in this invention.

[0023] Figure 3This is a structural diagram of the photocatalytic module in this invention.

[0024] Figure 4 This is a structural diagram of the precipitation module in this invention.

[0025] In the diagram: 1. Water inlet module; 101. Water inlet tank; 102. Return pipe; 103. Agitator; 104. Level gauge; 105. Water inlet pipe I; 106. Water outlet pipe I; 2. Photocatalysis module; 201. Reactor; 202. Catalyst reaction tube; 203. Illumination component; 204. Exhaust fan; 205. Temperature sensor; 206. Solenoid valve I; 207. Air inlet pipe; 208. Exhaust pipe; 209. Light shield; 210. Mounting plate; 3. Sedimentation module; 301. Sedimentation tank; 302. Water outlet pipe II; 303. Water inlet pipe II; 304. Flushing pipe; 305. Mud level gauge; 306. Nozzle; 307. Solenoid valve II; 308. Return pipe; 309. Water outlet solenoid valve; 4. Circulation module; 5. Conveying module; 6. Control cabinet. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] Example 1: As Figures 1-4 As shown, this invention discloses a continuous flow photocatalytic reactor for degrading SDBS. The reactor comprises an inlet module 1, a photocatalytic module 2, and a sedimentation module 3 arranged sequentially in the direction of water flow, connected by a transport pipeline 5. Water sedimented in the sedimentation module 3 flows back to the inlet module 1 via a circulation pipeline 4. A transport pump and flow meter are installed on the transport pipeline 5 between the inlet module 1 and the photocatalytic module 2, and a circulation pump and flow meter are installed on the circulation pipeline 4. The inlet module 1, photocatalytic module 2, sedimentation module 3, transport pump, circulation pump, and each flow meter are connected to a control cabinet 6 to control the operation of each module and pump. The inlet module 1 contains a mixed catalyst and SDBS wastewater. The photocatalytic module 2 includes a reactor 201 and a light shield 209. A catalyst reaction tube 202 is located at the center of the reactor 201, and a light-emitting component 203 is evenly distributed in a ring around the catalyst reaction tube 202, parallel to its axis. Both ends of the catalyst reaction tube 202 extend out of the mounting plates 210 at both ends of the reactor 201 and are connected to the conveying pipeline 5. A light shield 209 is fitted around the outer periphery of the reactor 201. An air inlet pipe 207 and an exhaust pipe 208 are respectively connected to the opposite side walls of the light shield 209, and the air inlet pipe 207 and the exhaust pipe 208 are respectively close to the two ends of the reactor 201. An exhaust fan 204 is provided on the exhaust pipe 208. The exhaust fan 204, together with the exhaust pipe 208 and the air inlet pipe 207, realizes ventilation and heat dissipation inside the reactor 201 and prevents the light source from overheating.

[0028] The reactor 201 provides space for photocatalytic reaction. Both ends are fixed to the mounting plate 210 by bolts. A safety isolation solenoid valve I 206 is installed on the catalyst reaction tube 202 extending out of the mounting plate 210 of the reactor 201. This valve is used to realize the opening and closing and isolation of the reaction tube from the device. The safety isolation solenoid valve I 206 is connected to the control cabinet 6. The safety isolation solenoid valve I 206 remains open during the entire operation of the device. When the control cabinet 6 receives an abnormal signal or needs to perform maintenance on the entire device, it automatically closes the safety isolation solenoid valves I 206 at both ends, isolating the reactor 201 from the entire device of the present invention.

[0029] The illumination component 203 is used to provide uniform ultraviolet light to excite the catalyst. It includes an ultraviolet light-emitting diode and a reflector tube sleeved outside the ultraviolet light-emitting diode. The wavelength of the ultraviolet light-emitting diode is 365 nm. The catalyst reaction tube 202 is made of quartz glass. Temperature sensors 205 are installed on the outer walls of both ends of the catalyst reaction tube 202 placed in the reactor 201. The temperature sensors 205 are connected to the control cabinet 6.

[0030] The inner wall of the light shield 209 is coated with a reflective coating to improve the utilization rate of the light source and the uniformity of illumination; the two mounting plates 210 of the reactor 201 are coated with a reflective coating corresponding to the inner side of the reactor; and the catalyst in the catalyst reaction tube 202 is a titanium dioxide-based photocatalyst.

[0031] The sedimentation module 3 includes a sedimentation tank 301. The bottom of the sedimentation tank 301 is a conical structure with a cone slope ranging from 45° to 60°, which facilitates the sedimentation and concentration of catalyst particles. The bottom outlet of the conical structure is connected to a return pipe 308. The sedimentation tank 301 has an inlet pipe II 303 and an outlet pipe II 302 arranged at staggered heights on opposite side walls. A flushing pipe 304 is installed at the bottom of the sedimentation tank 301, with one end extending into the sedimentation tank 301. The flushing pipe 304 located inside the sedimentation tank 301 is equipped with multiple nozzles 306 that spray towards the conical surface. A mud level gauge 305 is installed on the middle side wall of the sedimentation tank 301.

[0032] The outlet pipe II 302 is equipped with an outlet solenoid valve 309 connected to the control cabinet 6. The outlet solenoid valve 309 is normally in the open state to ensure that the compliant effluent is discharged normally. When the effluent does not meet the standards and needs to be returned for treatment, the outlet solenoid valve 309 is closed, so that the non-compliant wastewater returns to the inlet module 1 through the circulation pipe 4 for photocatalytic degradation again. The upper clear liquid is discharged through the outlet pipe II 302 to achieve the function of solid-liquid separation. The outlet solenoid valve 309 controls the flow of water, and in conjunction with the circulation pipe 4, the non-compliant wastewater is returned for retreatment.

[0033] The flushing pipe 304 is connected to an external water source and is equipped with a solenoid valve II 307 connected to the control cabinet 6 to control the external water source to enter the flushing pipe 304 to flush the sedimentation tank 301.

[0034] The water inlet module 1 includes a water inlet tank 101 and a cover plate for sealing the upper port of the water inlet tank 101. A stirring paddle 103 with its stirring end inside the water inlet tank 101 is installed on the cover plate for preliminary mixing of the catalyst and SDBS wastewater. A water outlet pipe I 106 is provided at the bottom of the water inlet tank 101, and the water outlet pipe I 106 is connected to the catalyst reaction tube 202 of the photocatalytic module 2 via a conveying pipe 5. A return pipe 102 and a water inlet pipe I 105 are provided near the top side wall of the water inlet tank 101, and the return pipe 102 and the water inlet pipe I 105 are staggered at 90-180°. The water inlet tank 101 contains the SDBS wastewater and catalyst, providing a preliminary mixing space. Simultaneously, the cover plate seals the water inlet tank 101 to prevent contamination and volatilization. The stirring paddle 103 ensures thorough mixing of the SDBS wastewater and catalyst, improving reaction efficiency and uniformity.

[0035] An online SDBS concentration sensor is installed on the inlet pipe I105 of the inlet tank 101, which can monitor the SDBS concentration of the inlet water in real time. A level gauge 104 is installed inside the inlet tank 101. Both the online SDBS concentration sensor and the level gauge 104 are connected to the control cabinet 6.

[0036] The control cabinet 6 is equipped with an integrated controller that connects to the level gauge 104, sludge level gauge 305, temperature sensor 205, SDBS concentration online sensor, transfer pump, circulation pump, solenoid valve I 206, solenoid valve II 307, outlet solenoid valve 309, and various flow meters to achieve fully automatic operation and adaptive parameter adjustment of the device. The inlet module 1, photocatalytic module 2, and sedimentation module 3 are all supported by external support components, which is a conventional technology and will not be described in detail.

[0037] Example 2: This invention also provides a control method for the continuous flow photocatalytic reaction device for degrading SDBS, which achieves efficient and stable degradation of SDBS through multi-parameter linkage control; including: S1: The SDBS wastewater to be treated and the titanium dioxide-based catalyst are continuously added into the inlet tank 101, and the agitator 103 is started to continuously mix at a speed of 120 r / min to form a uniform mixture. S2: Adjust the parameters of the central control cabinet 6 and, by pre-setting the flow rate of the delivery pump, stabilize the hydraulic retention time of the wastewater in the reactor 201 between 30 and 60 minutes to ensure the full degradation of SDBS. S3: Start the delivery pump to continuously deliver the mixture to the catalyst reaction tube 202 at a set flow rate. During the continuous flow, the mixture is irradiated by ultraviolet light and undergoes a photocatalytic degradation reaction. The level gauge 104 monitors the level of the water tank 101 in real time and sends feedback to the control cabinet 6. When the level is below 20%, a low-level alarm is issued to remind the operator to replenish the mixture in time. When the level is below 10%, the control cabinet automatically stops the delivery pump and turns off the light component 203, and issues a serious alarm. The system can only be manually reset and restarted after the level rises back to above 20%. S4: An online SDBS concentration sensor installed on the inlet pipe I105 of the inlet tank 101 provides real-time data feedback and sends the signal back to the control cabinet 6. The ultraviolet light intensity is adjusted according to the SDBS concentration: when the concentration is higher than 100 mg / L, the light intensity is 100%; when the concentration is 50-100 mg / L, the light intensity is 70%; and when the concentration is lower than 50 mg / L, the light intensity is 50%. The light component 203 is linked to the delivery pump. After the delivery pump starts, the control cabinet 6 automatically turns on the light component 203 after a preset delay time. The preset delay time is 2-5 seconds, which is a fixed value pre-calibrated and stored in the control cabinet based on the internal volume of the delivery pipeline 5 and the flow rate of the delivery pump, to ensure that the mixture has stably filled the reactor 201 by the end of the delay. When the delivery pump stops, the light component 203 immediately turns off automatically. S5: Temperature sensor 205 monitors the temperature in reactor 201 in real time and feeds the signal back to control cabinet 6. When the temperature is greater than 30 ℃, exhaust fan 204 starts automatically and increases its speed as the temperature rises. When the temperature exceeds 40 ℃ but does not exceed 45 ℃, exhaust fan 204 increases to the maximum safe speed and the power of the light source is reduced to 80% of the rated value. If the abnormal high temperature in the reactor exceeds 45 ℃, the power of the light source is further reduced to 50% of the rated value, and exhaust fan 204 maintains the maximum speed. If the temperature continues to rise to 50 ℃, the power supply to the light source is automatically cut off, and the system is manually reset after the temperature drops back to the safe threshold. S6: After the mixture reacts, it enters the settling tank 301 for sedimentation, achieving solid-liquid separation. The catalyst deposition thickness in the tank is monitored in real time by the mud level gauge 305. When the catalyst deposition thickness exceeds 10 cm, the backwashing and catalyst recovery procedure is triggered: the solenoid valve II 307 on the flushing pipe 304 is opened, and the nozzle 306 flushes for 60 seconds, stops for 30 seconds, and repeats this 3 times to disperse and resuspend the deposited catalyst. After flushing, the circulation pump on the circulation pipe 4 is automatically started and runs for 5 seconds. The catalyst slurry, which has been rinsed and resuspended in the settling tank 301, is returned to the inlet water tank 101. At the same time, the frequency of the circulation pump is adjusted according to the liquid level in the settling tank 301. When the liquid level is higher than 50% of the effective height of the tank, the circulation pump runs at full speed at the rated speed; when the liquid level is in the range of 30% to 50%, the frequency gradually decreases to 50% to 60% of the rated speed; when the liquid level is lower than 30%, the frequency decreases to 20% to 30% of the rated speed; when the liquid level is lower than 10%, the circulation pump is immediately stopped and a low-level alarm is triggered to prevent cavitation. Every two hours, the operator manually collects the supernatant from sedimentation tank 301 and measures the SDBS concentration using a UV-Vis spectrophotometer. If the test results show that the emission standards are not met, the operator manually triggers one or more of the following measures through the human-machine interface of control cabinet 6: ① Increase light intensity: Increase the light intensity by 5%~10% each time, run it stably for 30 minutes after adjustment and retest. Repeat the above steps until the light intensity reaches the rated maximum value; ② Extend the hydraulic residence time: Each time the adjustment is made, the frequency of the delivery pump is reduced to decrease the inlet flow rate by 10% to 20%, and the hydraulic residence time is extended to 1.1 to 1.25 times the original value. If the adjustment is made multiple times, the cumulative extended hydraulic residence time shall not exceed twice the original value. ③ Recirculation treatment: Part of the substandard effluent is returned to the inlet tank 101 through the circulation pipeline for further treatment, and the recirculation ratio is controlled between 10% and 80%.

[0038] The control method of this invention, through the above steps and feedback control, ensures that the photocatalytic reaction always proceeds in a highly efficient and stable state, ultimately achieving efficient degradation of SDBS wastewater and long-term stable operation of the system.

[0039] The parts not described in detail in this application are all existing conventional technologies and will not be elaborated here.

[0040] It is understood that the above specific description of the present invention is only for illustrating the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of the present invention.

Claims

1. A continuous flow photocatalytic reaction device for degrading SDBS, characterized in that: The water inlet module (1), photocatalytic module (2), and sedimentation module (3) are arranged sequentially according to the water flow direction, and are connected by a conveying pipeline (5). The water after sedimentation in the sedimentation module (3) flows back to the water inlet module (1) through a circulation pipeline (4). A conveying pump is installed on the conveying pipeline (5) between the water inlet module (1) and the photocatalytic module (2), and a circulation pump is installed on the circulation pipeline (4). The water inlet module (1), photocatalytic module (2), sedimentation module (3), conveying pump, and circulation pump are all connected to a control cabinet (6) to control the operation of each module and each pump. The water inlet module (1), photocatalytic module (2), sedimentation module (3), conveying pump, and circulation pump are all connected to a control cabinet (6) to control the operation of each module and each pump. 1) A mixture of built-in catalyst and SDBS wastewater; the photocatalytic module (2) includes a reactor (201), a light shield (209), a catalyst reaction tube (202) located at the center of the reactor (201), and a light irradiation component (203) that is parallel to the axis of the catalyst reaction tube (202) and evenly distributed in a ring around the catalyst reaction tube. Both ends of the catalyst reaction tube (202) extend out of the reactor (201) mounting plate (210) and connect to the conveying pipeline (5); the light shield (209) is fitted around the outer periphery of the reactor (201), and an air inlet pipe (207) and an exhaust pipe (208) are respectively connected to the opposite side walls of the light shield (204), and the air inlet pipe (207) and the exhaust pipe (208) are close to the two ends of the reactor, and an exhaust fan (204) is provided on the exhaust pipe (208).

2. The reaction apparatus according to claim 1, characterized in that: Each of the catalyst reaction tubes (202) extending from the end plates (210) of the reactor (201) is provided with a safety isolation solenoid valve I (206). The safety isolation solenoid valve I (206) is connected to the control cabinet (6). The safety isolation solenoid valve I (206) remains open during the operation of the entire device. When the control cabinet (6) receives an abnormal signal or needs to perform maintenance on the entire device, it automatically closes the safety isolation solenoid valves I (206) at both ends to isolate the reactor (201) from the entire device.

3. The reaction apparatus according to claim 1, characterized in that: The illumination component (203) includes an ultraviolet light-emitting diode and a reflector tube sleeved outside the ultraviolet light-emitting diode. The wavelength of the ultraviolet light-emitting diode is 365 nm. The catalyst reaction tube (202) is made of quartz glass. Temperature sensors (205) are installed on the outer walls of both ends of the catalyst reaction tube (202) placed in the reactor (201). The temperature sensors (205) are connected to the control cabinet (6) via signal.

4. The reaction apparatus according to claim 1, characterized in that: The inner wall of the light shield (209) is coated with a reflective coating, and the two mounting plates (210) of the reactor (201) are coated with a reflective coating on the inner side of the reactor. The catalyst in the catalyst reaction tube (202) is a titanium dioxide-based photocatalyst.

5. The reaction apparatus according to claim 1, characterized in that: The sedimentation module (3) includes a sedimentation tank (301). The bottom of the sedimentation tank (301) is a conical structure with a cone slope ranging from 45° to 60°. The bottom outlet of the conical structure is connected to a return pipe. The sedimentation tank (301) has an inlet pipe II (303) and an outlet pipe II (302) arranged at staggered heights on opposite side walls. A flushing pipe (304) with one end extending into the sedimentation tank (301) is installed at the bottom of the sedimentation tank (301). The flushing pipe (304) located inside the sedimentation tank (301) is provided with multiple nozzles (306) that spray towards the conical surface. A mud level gauge (305) is provided on the middle side wall of the sedimentation tank (301).

6. The reaction apparatus according to claim 5, characterized in that: The outlet pipe II (302) is equipped with an outlet solenoid valve (309) connected to the control cabinet (6). The outlet solenoid valve (309) is normally in the open state to ensure that the compliant outlet water is discharged normally. When the outlet water does not meet the standard and needs to be returned for treatment, the outlet solenoid valve (309) is closed, so that the non-compliant wastewater returns to the inlet module (1) through the circulation pipeline (4) for photocatalytic degradation again.

7. The reaction apparatus according to claim 5, characterized in that: The flushing pipe (304) is connected to an external water source and is equipped with a solenoid valve (307) connected to the control cabinet to control the external water source to enter the flushing pipe to flush the sedimentation tank (301).

8. The reaction apparatus according to claim 1, characterized in that: The water inlet module (1) includes a water inlet tank (101) and a cover plate for sealing the upper port of the water inlet tank (101). A stirring paddle (103) with the stirring end inside the water inlet tank (101) is installed on the cover plate for preliminary mixing of the catalyst and SDBS wastewater. A water outlet pipe I (106) is provided at the bottom of the water inlet tank (101). The water outlet pipe I (106) is connected to the catalyst reaction tube (202) of the photocatalytic module (2) through a conveying pipeline (5). A return pipe (102) and a water inlet pipe I (105) are provided on the side wall near the top of the water inlet tank (101). An online SDBS concentration sensor is installed on the water inlet pipe I (105) of the water inlet tank (101). A level gauge (104) is installed inside the water inlet tank (101). The online SDBS concentration sensor and the level gauge (104) are both connected to the control cabinet (6).

9. A control method for a reaction apparatus as described in any one of claims 1-8, characterized in that, include: SDBS wastewater and titanium dioxide-based catalyst are continuously fed into the inlet tank (101), and the stirring paddle (103) is started to continuously mix at a speed of 120 r / min to form a uniform mixture. Adjust the parameters of the central control cabinet (6) and, by setting the flow rate of the delivery pump, stabilize the hydraulic residence time of the wastewater in the reactor (201) at 30 to 60 minutes to ensure the full degradation of SDBS. The delivery pump is started to continuously deliver the mixture to the catalyst reaction tube (202) at a set flow rate. During the continuous flow, the mixture is irradiated by ultraviolet light from the light-emitting component (203) and undergoes photocatalytic degradation reaction. The level gauge (104) monitors the level of the water tank (101) in real time and feeds it back to the control cabinet (6). When the level is below 20%, the control cabinet (6) issues a low-level alarm to prompt the replenishment of the mixture. When the level is below 10%, the control cabinet automatically stops the delivery pump and shuts down the light-emitting component (203), and issues a serious alarm. The system is reset and restarted after the level rises above 20%. The signal is fed back to the control cabinet (6) through the online SDBS concentration sensor on the inlet pipe I (105). The ultraviolet light intensity is adjusted according to the SDBS concentration: when the concentration is higher than 100 mg / L, the light intensity is 100%; when the concentration is 50-100 mg / L, the light intensity is 70%; when the concentration is lower than 50 mg / L, the light intensity is 50%. The light component (203) is linked with the delivery pump. After the delivery pump starts, the light component (203) will automatically turn on after a delay of 5-10 seconds. When the delivery pump stops, the light component (203) will be turned off immediately. Temperature sensor (205) monitors the temperature in reactor (201) in real time and feeds it back to control cabinet (6): when the temperature is greater than 30℃, exhaust fan (204) is started and speed increases with temperature rise; when the temperature is between 40℃ and 45℃, exhaust fan (204) is increased to maximum safe speed and the power of light source of light component (203) is reduced to 80% of the rated value; if the temperature is greater than 45℃, the power of light source is further reduced to 50% of the rated value and exhaust fan (204) maintains maximum safe speed; if the temperature continues to rise to 50℃, the power of light source is automatically cut off and manually reset after the temperature drops back to the safe threshold. After the mixture reacts, it enters the sedimentation tank (301) for sedimentation. When the catalyst deposition thickness exceeds 10 cm as detected by the mud level gauge (305), the control cabinet (6) automatically triggers the backwashing and catalyst recovery program: the solenoid valve (307) on the flushing pipe (304) is opened, and the nozzle (306) flushes for 60 s, stops for 30 s, and repeats the cycle 3 times to disperse and resuspend the deposited catalyst; after the flushing is completed, the circulation pump on the circulation pipeline (4) is automatically started and runs for 5 hours. The catalyst slurry that has been rinsed and resuspended in the settling tank (301) is sent back to the water inlet tank (101). The frequency of the circulating pump is adjusted according to the liquid level in the settling tank (301). When the liquid level is higher than 50% of the effective height of the tank, the circulating pump runs at full speed at the rated speed. When the liquid level is in the range of 30% to 50%, the frequency is gradually reduced to 50% to 60% of the rated speed. When the liquid level is lower than 30%, the frequency is reduced to 20% to 30% of the rated speed. When the liquid level is lower than 10%, the circulating pump is stopped immediately and a low-level alarm is triggered.

10. The method according to claim 9, characterized in that: Check the SDBS concentration in the supernatant of the settling tank (301) every 2 hours; if it does not meet the standard, manually trigger one or more of the following measures: ① Increase light intensity: Increase the light intensity by 5%~10% each time, run it stably for 30 minutes after adjustment and retest. Repeat the above steps until the light intensity reaches the rated maximum value; ② Extend the hydraulic residence time: Each time the adjustment is made, the frequency of the delivery pump is reduced to decrease the inlet flow rate by 10% to 20%, and the hydraulic residence time is extended accordingly to 1.1 to 1.25 times the original value; if the adjustment is made multiple times, the cumulative extended hydraulic residence time shall not exceed twice the original value. ③ Recirculation treatment: Part of the substandard effluent is returned to the inlet tank (101) through the circulation pipeline (4) for further treatment. The recirculation ratio is controlled at 10%~80%.

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