Water turbine power generation utilization system for domestic sewage plant

Abstract

The invention relates to the technical field of hydroelectric power generation, in particular to a water turbine power generation utilization system for a domestic sewage plant. The system comprises a water turbine, a planetary gearbox, a generator, an electric energy storage facility, a domestic sewage flow channel and an intelligent regulation and control unit, the water turbine is fixed to the bottom of the domestic sewage flow channel through a liftable support, 24 blades are evenly distributed on the outer edge of the water turbine in the circumferential direction, and the immersion depth of the blades is 1 / 5 of the total height; the water turbine is connected with an input shaft of the planetary gearbox; the output end of the generator is connected with the electric energy storage facility through a cable, and electric energy stored by the electric energy storage facility is converted and used for being absorbed and utilized by various electrical equipment of a domestic sewage plant; the intelligent regulation and control unit is used for monitoring the sewage flow and the rotating speed of the water turbine in real time and adjusting the blade installation angle or the inclination angle of the flow guide plate to optimize the power generation efficiency. The power generation device can store energy to meet various energy consumption devices, and therefore the power generation efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydroelectric power generation, and in particular to a water turbine power generation utilization system for domestic sewage treatment plants. Background Art

[0002] In the context of global climate change and the increasing depletion of fossil energy, the new energy industry is gradually becoming an important force in promoting global energy transformation and achieving sustainable development. As one of the world's largest energy consumers and carbon emitters, China's development in the new energy field has been particularly remarkable in recent years. It is necessary to place the technological innovation of the new energy industry development and energy storage technology at the core.

[0003] Hydroelectric power generation is a green and zero-carbon operation and environmentally friendly power generation mode. However, in order to effectively utilize natural water energy, current hydroelectric power generation facilities need to build large reservoirs such as dams, which have a long construction period and high investment costs, posing a great restriction on the widespread promotion of hydroelectric power generation.

[0004] Domestic sewage generally contains organic matter, nitrogen, phosphorus, pathogenic bacteria, etc. Therefore, frequent discharge will cause the growth of pathogenic bacteria in the environment. A large amount of sewage is directly discharged into the surrounding water environment, which will cause serious water pollution problems over time. Therefore, domestic sewage needs to be centrally treated harmlessly before power generation. However, sewage centralized treatment is an industry with relatively high power consumption and relatively high costs, which has a certain impact on the development of sewage treatment, thereby reducing the power generation utilization efficiency. Summary of the Invention

[0005] Based on this, it is necessary for the present invention to provide a water turbine power generation utilization system for domestic sewage treatment plants. By placing a vane-type water turbine on the flow channel where a large amount of domestic sewage circulates in the domestic sewage treatment plant, the vanes with the same shape and structure are evenly distributed on the outer edge of the water turbine. Only 1 / 5 of the vanes are immersed in the domestic sewage. The vanes move under the vertical thrust of the domestic sewage, and the vanes drive the water turbine to start rotating. The central shaft of the water turbine is connected to the low-speed input shaft of the planetary gearbox and drives it to rotate. The high-speed output shaft of the planetary gearbox is connected to the input shaft of the generator for high-speed rotation. The generator shaft rotates at a high speed to generate electricity. The electric energy generated by the generator is converted through lines and power facilities and stored in the power energy storage facility. After the power energy storage facility releases the electricity, it is used for various high-power-consuming equipment in the domestic sewage treatment plant. This process is continuously repeated, which can achieve the good effect of cost savings and improving the power generation utilization efficiency of sewage, thereby solving at least one of the above technical problems.

[0006] To achieve the above object, a water turbine power generation utilization system for domestic sewage treatment plants includes: a water turbine, a planetary gearbox, a generator, a power energy storage facility, a domestic sewage flow channel, and an intelligent control unit, wherein:

[0007] The water turbine is fixed to the bottom of the domestic sewage flow channel through a liftable bracket. 24 blades are evenly distributed circumferentially on its outer edge. The immersion depth of the blades is 1 / 5 of the total height of the blades, and the installation angle of the blades is adjustable, with an adjustment range of 15° to 45° to adapt to domestic sewage with different flow rates from the domestic sewage treatment plant. The central shaft of the water turbine is connected to the input shaft of the planetary gearbox through a coupling. The planetary gearbox is a three-stage speed-changing mechanism with a speed ratio of 1:10 to 1:30 and a transmission efficiency of ≥92% to increase the low-speed rotation of the water turbine at 10 to 50 rpm to 1000 to 1500 rpm required by the generator. The output end of the generator connects the generated electric energy to the power energy storage facility through a cable. The power energy storage facility includes a supercapacitor module, a lithium-ion battery pack, and an inverter, which are used to store and distribute the electric energy. The electric energy stored in the power energy storage facility is converted for consumption by various electrical equipment in the domestic sewage treatment plant. The cross-section of the domestic sewage flow channel is trapezoidal, and a flow guide plate with an inclination angle of 30° to 60° is provided at the bottom. The flow guide plate is provided with flow disturbance holes with a pore diameter of 5 to 10 mm. The intelligent control unit includes a flow sensor, a rotational speed detector, and a PLC controller to use the flow sensor and the rotational speed detector to monitor the sewage flow rate and the rotational speed of the water turbine in real time, and dynamically adjust the blade installation angle or the inclination angle of the flow guide plate according to the PLC controller to optimize the power generation efficiency.

[0008] Preferably, the blades are made of carbon fiber reinforced polyether ether ketone composite material, and their cross-section is an asymmetric airfoil structure. The leading edge thickness is 1.5 to 2 times the trailing edge thickness, and the surface of the blades is coated with a nano-hydrophobic coating. The contact angle of the nano-hydrophobic coating is greater than 150° to reduce the attachment of organic matter and suspended solids in the sewage in the domestic sewage flow channel. The blades are connected to the hub through a flange. The flange is provided with an arc-shaped chute, and the blades are fixed by bolts passing through the arc-shaped chute. After loosening the bolts, the blade angle can be adjusted manually or through a servo motor, and the adjustment accuracy is ±1°.

[0009] Preferably, the nano-hydrophobic coating is composed of silica nanoparticles and fluorosilane resin. The thickness of the nano-hydrophobic coating is 50 to 100 μm, and the surface roughness Ra ≤ 0.2 μm. The chord length of the airfoil of the blade is 200 to 300 mm, and the aspect ratio is 3:1 to 5:1. The leading edge is provided with wear-resistant ceramic inserts, and the trailing edge is provided with a serrated structure to suppress vortex shedding.

[0010] Preferably, the planetary gearbox includes a sun gear, planet gears, a ring gear and a planet carrier. The sun gear is key-connected to the input shaft. The planet gears are mounted on the planet carrier through needle roller bearings. The ring gear is fixed to the housing. The gears of the planetary gearbox are made of 20CrMnTi alloy steel treated by nitriding, and the tooth surface hardness is ≥60HRC. The housing of the planetary gearbox is of split design, with an O-ring seal provided at the joint surface and filled with food-grade grease inside. The dropping point of the grease is ≥250°C.

[0011] Preferably, the planetary gearbox is also integrated with an oil fluid monitoring module, including an oil temperature sensor, a moisture sensor and a particle counter, to monitor the state of the grease in real time. A magnetic seal device is provided at the output shaft end of the planetary gearbox to prevent sewage intrusion. The cooling method of the planetary gearbox is a combination of air cooling and water cooling. The air cooling is achieved through the heat dissipation fins outside the housing, while the water cooling is achieved through the circulating cooling water in the copper pipes wound around the housing.

[0012] Preferably, the guide plate is made of 304 stainless steel, and a WC-Co wear-resistant layer is laser cladded on the surface. The spoiler holes are distributed in a diamond array, and the hole spacing is 2-3 times the hole diameter. The guide plate is connected to the bottom plate of the flow channel through a hinge, and its angle adjustment mechanism is an electric push rod or a hydraulic cylinder. The stroke of the electric push rod or the hydraulic cylinder is linked with the PLC controller to automatically adjust the inclination angle of the guide plate according to the data of the flow sensor and the rotational speed detector, and the adjustment response time is ≤5 seconds.

[0013] Preferably, a grid-type impurity interception device is also provided on the downstream side of the guide plate. The grid spacing is 10-15mm, and the grid is inclined at 45° to the horizontal plane. A buffer gap of 50-100mm is left between the grid-type impurity interception device and the guide plate. A high-pressure nozzle is installed at the buffer gap, and the high-pressure nozzle is connected to the flushing water pump of the domestic sewage treatment plant through a pipeline for regular reverse flushing to remove the blockage of the grid.

[0014] Preferably, the supercapacitor module of the power energy storage facility is composed of multiple groups of 2.7V / 3000F capacitor monomers connected in series, with a total capacity of ≥10kWh and a charge-discharge efficiency of ≥95%. The lithium-ion battery pack is of lithium iron phosphate system, with a rated voltage of 48V and a capacity of ≥100kWh, and is equipped with an active equalization management system. The inverter is of three-phase full-bridge topology structure, with a conversion efficiency of ≥98%, so as to synchronize the grid frequency and phase corresponding to the domestic sewage treatment plant in the grid-connected mode. The power energy storage facility also includes an energy management terminal, which is built-in with a dynamic electricity price model and a load forecasting algorithm for preferentially releasing the stored energy electricity during peak electricity consumption periods. The energy management terminal is also connected to the cloud monitoring platform through a 4G / 5G module, supporting remote adjustment of charge-discharge strategies and fault diagnosis.

[0015] Preferably, the charge and discharge strategy includes:

[0016] Peak shaving mode: when the power consumption load of the domestic sewage treatment plant is detected to be > the rated power of the generator, the supercapacitor discharges preferentially, and the response time < 10 ms;

[0017] Valley filling mode: during the low-load period at night, the surplus electric energy is stored by the lithium-ion battery pack;

[0018] Emergency power supply mode: when the power supply of the domestic sewage treatment plant is interrupted, the corresponding component equipment of the domestic sewage treatment plant can be maintained to operate for ≥ 4 hours.

[0019] Preferably, the PLC controller of the intelligent regulation unit is built-in with a PID control algorithm and a fuzzy logic module. The input variables include flow rate, rotational speed, water level, and vibration data, and the output variables are blade angle, deflector position, and spoiler hole opening; the PLC controller communicates with the central control system of the domestic sewage treatment plant through industrial Ethernet and supports the Modbus TCP / IP protocol; the PLC controller is also connected to an acoustic monitoring module. The acoustic monitoring module includes an underwater microphone and a spectrum analyzer, which are used to detect the abnormal noise spectrum during the operation of the water turbine. When continuous broadband noise of 500 Hz - 2 kHz appears in the abnormal noise spectrum, it is determined as blade cavitation corrosion, so as to automatically trigger a maintenance alarm and reduce the rotational speed of the water turbine to a safety threshold. The safety threshold includes a lower limit threshold ≥ 15 rpm to ensure that the water turbine overcomes the static friction resistance and avoids sediment attachment to the blade caused by low flow velocity; an upper limit threshold ≤ 75 rpm to prevent cavitation corrosion and mechanical overload of the blade under high flow velocity; an emergency shutdown threshold ≥ 80 rpm to trigger the hard-wired protection circuit of the PLC controller, cut off the water flow, and start mechanical braking.

[0020] Advantages of the present invention:

[0021] The water turbine power generation utilization system proposed by the present invention for domestic sewage treatment plants is generally composed of a water turbine (with 24 blades thereon), a planetary gearbox, a generator, a power energy storage facility, a domestic sewage flow channel, and the corresponding component structures of an intelligent control unit. Compared with the prior art, the beneficial effects of this application are as follows: In this case, the design of the water turbine takes into account the variability of the flow rate of domestic sewage. Through adjustable blade angles and appropriate immersion depths, the water turbine can adapt to sewage with different flow rates, thus ensuring that the water turbine can operate effectively even at lower flow rates. The adjustable angle range of the blades is 15° to 45°, which can be adjusted according to the real-time flow rate, further improving the power generation efficiency of the water turbine and avoiding energy waste caused by changes in the flow rate. At the same time, the immersion depth of the blades is designed to be 1 / 5 of the total height of the blades, which helps to improve the contact efficiency between the water flow and the blades and maximize the utilization of the power of the water flow. Secondly, the use of the planetary gearbox provides an effective speed conversion for the water turbine. The three-stage speed change mechanism of the planetary gearbox increases the low-speed rotation of the water turbine from 10 to 50 rpm to the required speed of the generator, which is 1000 to 1500 rpm. The speed ratio is 1:10 to 1:30, and the transmission efficiency is ≥92%. This efficient transmission mechanism can efficiently convert the low speed of the water turbine into high-speed electrical energy output, ensuring that the generator can continuously and stably generate electricity and avoiding energy losses caused by speed mismatches. The design of the power energy storage facility further optimizes the energy utilization of the system. Through the combination of a supercapacitor module, a lithium-ion battery pack, and an inverter, electrical energy can be efficiently stored and distributed, and can be flexibly allocated according to the needs of different electrical equipment in the domestic sewage treatment plant. This design can not only ensure the power supply of the sewage treatment plant, but also balance the power fluctuations and improve the stability and safety of the system. In addition, the optimized design of the domestic sewage flow channel, through the guide plate with a bottom inclination angle of 30° to 60° and the flow disturbing holes with a flow disturbing function, can effectively guide the water flow, making the flow rate of the water flow more uniform when it enters the water turbine, reducing the energy loss caused by unstable water flow, and further improving the power generation efficiency of the water turbine.Finally, the introduction of the intelligent control unit enables the system to achieve real-time monitoring and dynamic adjustment. Through the cooperation of the flow sensor, speed detector, and PLC controller, the system can monitor the sewage flow and the water turbine speed in real time, and automatically adjust the blade angle and the inclination angle of the guide vane according to the data, so as to always maintain the optimal power generation state under different flow and velocity conditions. This intelligent adjustment not only improves the power generation efficiency, but also reduces the need for manual intervention in the system, and fully exploits the reuse value of domestic sewage again. While further reducing environmental pollution, it significantly reduces the operating cost of the sewage treatment plant. By effectively using the treated domestic sewage for hydropower generation, it is a green and clean energy source. There is no need to build large dams or reservoirs, and the investment cost is low, which is conducive to popularization and implementation in various places. The daily discharge volume of the treated domestic sewage is basically stable. Multiple water turbines can be installed in the same domestic sewage flow channel for power generation at the same time. The power generation stability is good, the daily power generation time is long, the power generation efficiency is high, and the daily power generation capacity is greatly improved, which can provide a stable power supply and reduce the dependence on traditional energy without mutual influence. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments read in conjunction with the accompanying drawings:

[0023] Figure 1 It is a partial structural schematic diagram of the water turbine power generation utilization system for domestic sewage treatment plants of the present invention;

[0024] Figure 2 It is the shape and distribution diagram of the water turbine blades of the present invention;

[0025] Description of the reference numerals: 1. Water turbine; 2. Planetary gearbox; 3. Generator; 4. Power energy storage facility; 5. Domestic sewage flow channel; 6. Blade. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The technical system of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] In addition, the accompanying drawings are only schematic illustrations of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus repeated descriptions thereof will be omitted. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. The functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor systems and / or microcontroller systems.

[0028] It should be understood that although the terms "first", "second", etc. may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, without departing from the scope of the exemplary embodiments, the first unit may be referred to as the second unit, and similarly the second unit may be referred to as the first unit. The term "and / or" used herein includes any and all combinations of one or more of the listed associated items.

[0029] To achieve the above object, please refer to Figures 1 to 2 , the present invention provides a water turbine power generation utilization system for a domestic sewage treatment plant. Please refer to Figure 1 shown in the figure, which is a schematic diagram of a partial composition structure of the water turbine power generation utilization system for a domestic sewage treatment plant according to the present invention. In this example, the system includes: a water turbine 1, a planetary gearbox 2, a generator 3, a power energy storage facility 4, a domestic sewage flow channel 5, and an intelligent control unit, where:

[0030] The water turbine 1 is fixed to the bottom of the domestic sewage flow channel 5 through a liftable support. 24 blades 6 are evenly distributed circumferentially on its outer edge. The immersion depth of the blades 6 is 1 / 5 of the total height of the blades 6, and the installation angle of the blades 6 is adjustable, with an adjustment range of 15° to 45°, so as to adapt to domestic sewage with different flow rates from the domestic sewage treatment plant; the central shaft of the water turbine 1 is connected to the input shaft of the planetary gearbox 2 through a coupling. The planetary gearbox 2 is a three-stage speed-changing mechanism, with a speed ratio of 1:10 to 1:30 and a transmission efficiency ≥ 92%, so as to increase the low-speed rotation of 10 to 50 rpm of the water turbine 1 to 1000 to 1500 rpm required by the generator 3; the output end of the generator 3 connects the generated electric energy to the power energy storage facility 4 through a cable. The power energy storage facility 4 includes a supercapacitor module, a lithium-ion battery pack and an inverter, and is used to store and distribute the electric energy. The electric energy stored in the power energy storage facility 4 is converted and used by various electrical equipment in the domestic sewage treatment plant; the cross-section of the domestic sewage flow channel 5 is trapezoidal, and a guide plate with an inclination angle of 30° to 60° is provided at the bottom. The guide plate is provided with flow-disturbing holes with a pore diameter of 5 to 10 mm; the intelligent control unit includes a flow sensor, a speed detector and a PLC controller, so as to use the flow sensor and the speed detector to monitor the sewage flow and the speed of the water turbine 1 in real time, and dynamically adjust the installation angle of the blades 6 or the inclination angle of the guide plate according to the PLC controller to optimize the power generation efficiency.

[0031] Preferably, the blade 6 is made of a carbon fiber reinforced polyetheretherketone composite material, and its cross-section is an asymmetric airfoil structure. The leading edge thickness is 1.5 to 2 times the trailing edge thickness. And the surface of the blade 6 is coated with a nano-hydrophobic coating, and the contact angle of the nano-hydrophobic coating is greater than 150°, so as to reduce the attachment of organic matter and suspended matter in the sewage in the domestic sewage flow channel 5; the blade 6 is connected to the hub through a flange. The flange is provided with an arc-shaped sliding groove, and the blade 6 is fixed by bolts passing through the arc-shaped sliding groove. After loosening the bolts, the angle of the blade 6 can be adjusted manually or by a servo motor, and the adjustment accuracy is ±1°.

[0032] Preferably, the nano-hydrophobic coating is composed of silica nanoparticles and fluorosilane resin. The thickness of the nano-hydrophobic coating is 50 to 100 μm, and the surface roughness Ra ≤ 0.2 μm; the airfoil chord length of the blade 6 is 200 to 300 mm, and the aspect ratio is 3:1 to 5:1. Its leading edge is provided with wear-resistant ceramic inserts, and its trailing edge is provided with a serrated structure to suppress vortex shedding.

[0033] Preferably, the planetary gearbox 2 includes a sun gear, planetary gears, a ring gear, and a carrier. The sun gear is key-connected to the input shaft. The planetary gears are mounted on the carrier through needle roller bearings. The ring gear is fixed to the housing. The gears of the planetary gearbox 2 are made of 20CrMnTi alloy steel treated by nitriding, and the tooth surface hardness is ≥60HRC. The housing of the planetary gearbox 2 is of split design, and an O-ring seal is provided at the joint surface. Food-grade grease is filled inside, and the dropping point of the grease is ≥250°C.

[0034] Preferably, the planetary gearbox 2 is also integrated with an oil condition monitoring module, including an oil temperature sensor, a moisture sensor, and a particle counter, to monitor the grease condition in real time. A magnetic seal device is provided at the output shaft end of the planetary gearbox 2 to prevent sewage intrusion. The cooling method of the planetary gearbox 2 is a combination of air cooling and water cooling. The air cooling is achieved through the heat dissipation fins outside the housing, and the water cooling is achieved through the circulating cooling water in the copper pipe wound around the housing.

[0035] Preferably, the deflector is made of 304 stainless steel, and a WC-Co wear-resistant layer is laser cladded on the surface. The spoiler holes are distributed in a diamond array, and the hole spacing is 2-3 times the hole diameter. The deflector is connected to the bottom plate of the flow channel through a hinge, and its angle adjustment mechanism is an electric push rod or a hydraulic cylinder. The stroke of the electric push rod or the hydraulic cylinder is linked with the PLC controller to automatically adjust the inclination angle of the deflector according to the data of the flow sensor and the speed detector, and the adjustment response time is ≤5 seconds.

[0036] Preferably, a grid-type impurity interception device is also provided on the downstream side of the deflector. The grid spacing is 10-15mm, and the grid is inclined at 45° to the horizontal plane. A buffer gap of 50-100mm is left between the grid-type impurity interception device and the deflector. A high-pressure nozzle is installed at the buffer gap. The high-pressure nozzle is connected to the flushing water pump of the domestic sewage treatment plant through a pipeline for regular reverse flushing to remove the grid blockage.

[0037] Preferably, the supercapacitor module of the power energy storage facility 4 is composed of multiple groups of 2.7V / 3000F capacitor monomers connected in series, with a total capacity of ≥10kWh and a charge-discharge efficiency of ≥95%. The lithium-ion battery pack is of lithium iron phosphate system, with a rated voltage of 48V and a capacity of ≥100kWh, and is equipped with an active equalization management system. The inverter is of three-phase full-bridge topology structure, with a conversion efficiency of ≥98%, so as to synchronize the grid frequency and phase corresponding to the domestic sewage treatment plant in the grid-connected mode. The power energy storage facility 4 also includes an energy management terminal, which is built-in with a dynamic electricity price model and a load forecasting algorithm for preferentially releasing stored energy electricity during peak electricity consumption periods. The energy management terminal is also connected to the cloud monitoring platform through a 4G / 5G module, supporting remote adjustment of charge-discharge strategies and fault diagnosis.

[0038] Preferably, the charge-discharge strategy includes:

[0039] Peak shaving mode: when the detected power consumption load of the domestic sewage treatment plant > the rated power of the generator 3, the supercapacitor discharges preferentially, and the response time < 10 ms;

[0040] Valley filling mode: during the low-load period at night, the excess electric energy is stored by the lithium-ion battery pack;

[0041] Emergency power supply mode: when the power supply of the domestic sewage treatment plant is interrupted, it can maintain the operation of the corresponding component equipment of the domestic sewage treatment plant for ≥ 4 hours.

[0042] Preferably, the PLC controller of the intelligent regulation unit is built-in with a PID control algorithm and a fuzzy logic module. The input variables include flow rate, rotational speed, water level, and vibration data, and the output variables are vane angles, deflector positions, and spoiler hole openings; the PLC controller communicates with the central control system of the domestic sewage treatment plant through an industrial Ethernet and supports the Modbus TCP / IP protocol; the PLC controller is also connected to an acoustic monitoring module, and the acoustic monitoring module includes an underwater microphone and a spectrum analyzer, which are used to detect the abnormal noise spectrum during the operation of the water turbine 1. When a continuous broadband noise of 500 Hz - 2 kHz appears in the abnormal noise spectrum, it is determined as vane cavitation corrosion, so as to automatically trigger a maintenance alarm and reduce the rotational speed of the water turbine 1 to a safety threshold, where the safety threshold includes a lower limit threshold ≥ 15 rpm to ensure that the water turbine 1 overcomes the static friction resistance and avoid sediment attachment on the vane 6 caused by low flow velocity; an upper limit threshold ≤ 75 rpm to prevent cavitation corrosion and mechanical overload of the vane 6 under high flow velocity; an emergency shutdown threshold ≥ 80 rpm to trigger the hard-wired protection circuit of the PLC controller, cut off the water flow, and start mechanical braking.

[0043] Embodiment 1

[0044] Taking a domestic sewage treatment plant with a daily treatment capacity of 50,000 m 3 as an example, the domestic sewage flows in the flow channel at a normal flow velocity. The flow sensor detects that the sewage flow rate is 80% of the designed flow rate, and the rotational speed detector detects that the rotational speed of the water turbine is 30 rpm.

[0045] Device operation: The water turbine 1 is fixed to the bottom of the domestic sewage flow channel 5 through a liftable bracket. The immersion depth of its 24 blades 6 is 1 / 5 of its total height. The installation angle of the blades 6 is adjusted to 30° according to the current sewage flow velocity to adapt to the water flow and efficiently capture energy. The planetary gearbox 2 uses a three-stage speed-changing mechanism to increase the rotational speed of the water turbine 1 from 30 rpm to 600 rpm at a speed ratio of 1:20 to meet the speed requirement of the generator 3. The corresponding input power during the transmission process is 1000 W. After passing through the transmission device, the output power is 930 W, and its transmission efficiency is 93%, meeting the design standard. The generator 3 operates at a rotational speed of 600 rpm, outputs electrical energy, and transmits it to the power energy storage facility 4 through a cable. The supercapacitor module and the lithium-ion battery pack in the power energy storage facility 4 start to store electrical energy. The supercapacitor module is composed of multiple groups of 2.7 V / 3000 F capacitor monomers connected in series, with a total capacity of 12 kWh. The lithium-ion battery pack is of the lithium iron phosphate system, with a rated voltage of 48 V and a capacity of 120 kWh, equipped with an active equalization management system. The inverter can convert the stored electrical energy into a form suitable for use by the electrical equipment in the domestic sewage treatment plant. The flow sensor and the rotational speed detector transmit real-time data to the PLC controller. The PLC controller analyzes based on the built-in PID control algorithm and the fuzzy logic module and obtains that the current input electrical energy is 1000 W, while the effective electrical energy generated is 985 W. It can be calculated that the power generation efficiency is 98.5%, which is in a relatively optimal state. Therefore, there is no need to adjust the angle of the blades 6 and the inclination angle of the deflector. In the current situation, the inclination angle of the deflector is 45°, the aperture of the turbulence holes is 8 mm, and they are distributed in a diamond array with a hole pitch of 20 mm.

[0046] Energy management: The energy management terminal, based on the dynamic electricity price model and the load prediction algorithm, determines that it is currently in the low electricity consumption period and preferentially stores electrical energy in the lithium-ion battery pack for subsequent use.

[0047] Embodiment 2

[0048] The daily treatment capacity of the domestic sewage treatment plant has increased to 60,000 m due to reasons such as the increased occupancy rate of the surrounding communities 3 , resulting in an increase in the sewage flow rate and a faster flow velocity in the domestic sewage flow channel 5. The flow sensor detects that the flow rate is 110% of the designed flow rate, and the rotational speed of the water turbine rises to 40 rpm.

[0049] Equipment operation and adjustment: After the PLC controller receives the data on the changes in flow rate and rotational speed, and after analysis and judgment, it is necessary to adjust the angle of blade 6 to optimize the power generation efficiency. The angle of blade 6 is adjusted to 35° through the servo motor. At the same time, according to the data from the flow sensor and the rotational speed detector, the electric push rod adjusts the tilt angle of the guide vane to 50° to change the water flow pattern and improve the energy capture efficiency of the water turbine. During the adjustment process, the adjustment response time of the guide vane is 4 seconds, meeting the design requirements. For other equipment, after the water turbine 1 adjusts the blade angle, it can make more effective use of the water flow energy. The planetary gearbox 2 continues to steadily increase the rotational speed of the water turbine 1 to the rotational speed required by the generator 3, and the output power of the generator 3 increases accordingly. The power energy storage facility 4 speeds up the charging speed to store more electric energy.

[0050] Energy management: The energy management terminal monitors that the electricity load of the domestic sewage treatment plant has not changed significantly and remains at a low level, and continues to store the excess electric energy in the lithium-ion battery pack.

[0051] Embodiment 3

[0052] After a heavy rainstorm, the influent flow rate of the domestic sewage treatment plant suddenly increased significantly, and the daily treatment volume reached 70,000 m 3 , and a large amount of debris was carried in the sewage. At the same time, the acoustic monitoring module detected abnormal noise during the operation of the water turbine 1. The spectral analysis showed continuous broadband noise in the range of 500 Hz - 2 kHz, and it was determined to be blade cavitation corrosion.

[0053] Emergency handling measures: Automatically trigger a maintenance alarm through the PLC controller and, according to preset safety thresholds, specifically including a lower limit threshold ≥ 15 rpm to ensure that the water turbine 1 overcomes static friction resistance and to prevent sediment attachment to the blades 6 caused by low flow rates; an upper limit threshold ≤ 75 rpm to prevent cavitation corrosion and mechanical overload of the blades 6 under high flow rates; an emergency shutdown threshold ≥ 80 rpm to trigger the hard-wired protection circuit of the PLC controller, cut off the water flow, and start mechanical braking. For example, when the rotational speed of the water turbine 1 drops to 50 rpm, the spoiler holes are simultaneously closed to reduce the impact of the water flow on the blades, and a large amount of debris is intercepted by the grid-type debris interception device. The high-pressure nozzles at the buffer gap start to work, periodically flushing in the reverse direction to remove grid blockages, prevent debris from entering the water turbine 1, and affect its normal operation. The state of the grease in the planetary gearbox 2 is also continuously monitored through the oil monitoring module to ensure the stable performance of the grease under abnormal conditions. At the same time, the magnetic seal device effectively prevents sewage from invading the interior of the planetary gearbox 2, ensuring its normal operation. Since the rotational speed of the water turbine 1 decreases, the output power of the generator 3 drops, but the supercapacitor module and the lithium-ion battery pack in the power energy storage facility 4 continue to supply power to the key electrical equipment in the domestic sewage treatment plant to maintain its normal operation. In the emergency power supply mode, ensure that the component equipment of the domestic sewage treatment plant can continue to operate for at least 4 hours to gain time for troubleshooting.

[0054] Subsequent handling: After receiving the maintenance alarm, the staff promptly inspect and maintain the blades 6, repair or replace the damaged blades 6, and at the same time clean the debris in the domestic sewage flow channel 5, check the operating conditions of each device, and ensure that the system can operate safely and stably after returning to normal.

[0055] Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Accordingly, all changes falling within the meaning and scope of the equivalent elements of the application documents are intended to be encompassed within the present invention.

[0056] The above description is only a specific implementation manner of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A water turbine power generation utilization system for domestic sewage treatment plants, characterized in that, Comprising: A water turbine (1), a planetary gearbox (2), a generator (3), a power energy storage facility (4), a domestic sewage flow channel (5) and a smart control unit, wherein: The water turbine (1) is fixed to the bottom of the domestic sewage flow channel (5) through a liftable bracket, and 24 blades (6) are evenly distributed circumferentially on its outer edge. The immersion depth of the blades (6) is 1 / 5 of the total height of the blades (6), and the installation angle of the blades (6) is adjustable, with an adjustment range of 15° to 45° to adapt to domestic sewage with different flow rates from a domestic sewage treatment plant; the central shaft of the water turbine (1) is connected to the input shaft of the planetary gearbox (2) through a coupling. The planetary gearbox (2) is a three-stage speed change mechanism with a speed ratio of 1:10 to 1:30 and a transmission efficiency ≥ 92% to boost the low-speed rotation of 10 - 50 rpm of the water turbine (1) to 1000 - 1500 rpm required by the generator (3); the output end of the generator (3) connects the generated electric energy to the power energy storage facility (4) through a cable. The power energy storage facility (4) includes a supercapacitor module, a lithium-ion battery pack and an inverter for storing and distributing the electric energy. The electric energy stored in the power energy storage facility (4) is converted for consumption by various electrical equipment in the domestic sewage treatment plant; the cross-section of the domestic sewage flow channel (5) is trapezoidal, and a flow guide plate with an inclination angle of 30° to 60° is provided at the bottom. The flow guide plate is provided with flow disturbance holes with a pore diameter of 5 - 10 mm; the smart control unit includes a flow sensor, a rotational speed detector and a PLC controller to use the flow sensor and the rotational speed detector to monitor the sewage flow rate and the rotational speed of the water turbine (1) in real time, and dynamically adjust the installation angle of the blades (6) or the inclination angle of the flow guide plate according to the PLC controller to optimize the power generation efficiency.

2. The water turbine power generation utilization system for domestic sewage treatment plants according to claim 1, characterized in that, The blades (6) are made of carbon fiber reinforced polyetheretherketone composite material, and their cross-section is an asymmetric airfoil structure. The leading edge thickness is 1.5 - 2 times the trailing edge thickness, and the surface of the blades (6) is coated with a nano-hydrophobic coating with a contact angle of the nano-hydrophobic coating greater than 150° to reduce the attachment of organic matter and suspended solids in the sewage in the domestic sewage flow channel (5); the blades (6) are connected to the hub through a flange. The flange is provided with an arc-shaped sliding groove, and the blades (6) are fixed by bolts passing through the arc-shaped sliding groove. After loosening the bolts, the angle of the blades (6) can be adjusted manually or through a servo motor, and the adjustment accuracy is ±1°.

3. The water turbine power generation utilization system for domestic sewage treatment plants according to claim 2, wherein The nano-hydrophobic coating is composed of silica nanoparticles and fluorosilane resin, and the thickness of the nano-hydrophobic coating is 50 - 100 μm, and the surface roughness Ra ≤ 0.2 μm; the airfoil chord length of the blades (6) is 200 - 300 mm, and the aspect ratio is 3:1 to 5:

1. Its leading edge is provided with a wear-resistant ceramic insert, and the trailing edge is provided with a serrated structure to suppress vortex shedding.

4. The water turbine power generation utilization system for domestic sewage treatment plants according to claim 1, wherein The planetary gearbox (2) includes a sun gear, planetary gears, a ring gear and a planet carrier. The sun gear is key-connected to the input shaft. The planetary gears are mounted on the planet carrier through needle roller bearings. The ring gear is fixed to the housing. The gears of the planetary gearbox (2) are made of 20CrMnTi alloy steel with nitriding treatment, and the tooth surface hardness is ≥60HRC. The housing of the planetary gearbox (2) is of split design, with an O-ring seal at the joint surface and filled with food-grade grease inside. The dropping point of the grease is ≥250°C.

5. The water turbine power generation utilization system for domestic sewage treatment plants according to claim 4, characterized in that The planetary gearbox (2) is also integrated with an oil monitoring module, including an oil temperature sensor, a moisture sensor and a particle counter, to monitor the state of the grease in real time. A magnetic seal device is provided at the output shaft end of the planetary gearbox (2) to prevent sewage from invading. The cooling method of the planetary gearbox (2) is a combination of air cooling and water cooling. The air cooling is achieved through the heat dissipation fins outside the housing, while the water cooling is achieved through the circulating cooling water in the copper pipes wound around the housing.

6. The water turbine power generation utilization system for domestic sewage treatment plants according to claim 1, characterized in that The flow guide plate is made of 304 stainless steel, and a WC-Co wear-resistant layer is laser cladded on the surface. The spoiler holes are distributed in a diamond array, and the hole spacing is 2-3 times the hole diameter. The flow guide plate is connected to the bottom plate of the flow channel through a hinge, and its angle adjustment mechanism is an electric push rod or a hydraulic cylinder. The stroke of the electric push rod or the hydraulic cylinder is linked with the PLC controller to automatically adjust the tilt angle of the flow guide plate according to the data of the flow sensor and the speed detector, and the adjustment response time is ≤5 seconds.

7. The water turbine power generation utilization system for domestic sewage treatment plants according to claim 6, characterized in that, A grid-type impurity interception device is also provided on the downstream side of the flow guide plate. The grid spacing is 10-15mm, and the grid is installed at an angle of 45° to the horizontal plane. A buffer gap of 50-100mm is left between the grid-type impurity interception device and the flow guide plate. A high-pressure nozzle is installed at the buffer gap. The high-pressure nozzle is connected to the flushing water pump of the domestic sewage treatment plant through a pipeline and is periodically flushed in the reverse direction to remove the blockage of the grid.

8. The water turbine power generation utilization system for domestic sewage treatment plants according to claim 1, characterized in that The supercapacitor module of the power energy storage facility (4) is composed of multiple groups of 2.7V / 3000F capacitor monomers connected in series, with a total capacity of ≥10kWh and a charge-discharge efficiency of ≥95%. The lithium-ion battery pack is of lithium iron phosphate system, with a rated voltage of 48V and a capacity of ≥100kWh, and is equipped with an active equalization management system. The inverter is of three-phase full-bridge topology structure, with a conversion efficiency of ≥98%, so as to synchronize the grid frequency and phase corresponding to the domestic sewage treatment plant in the grid-connected mode. The power energy storage facility (4) also includes an energy management terminal, which is built-in with a dynamic electricity price model and a load forecasting algorithm for preferentially releasing the stored energy during peak electricity consumption periods. The energy management terminal is also connected to the cloud monitoring platform through a 4G / 5G module, supporting remote adjustment of charge-discharge strategies and fault diagnosis.

9. The water turbine power generation utilization system for domestic sewage treatment plants according to claim 8, characterized in that, The charge-discharge strategies include: Peak shaving mode: When it is detected that the electricity consumption load of the domestic sewage treatment plant > the rated power of the generator (3), the supercapacitor discharges preferentially, and the response time <10ms. Valley filling mode: During the low-load period at night, the lithium-ion battery pack is used to store excess electric energy. Emergency power supply mode: when the power supply of the domestic sewage treatment plant is interrupted, the corresponding component equipment of the domestic sewage treatment plant can be maintained to operate for ≥ 4 hours.

10. The water turbine power generation utilization system for domestic sewage treatment plants according to claim 1, wherein, The PLC controller of the intelligent control unit is built-in with a PID control algorithm and a fuzzy logic module. The input variables include flow rate, rotational speed, water level, and vibration data, and the output variables are blade angle, deflector position, and spoiler hole opening; the PLC controller communicates with the central control system of the domestic sewage treatment plant through industrial Ethernet and supports the Modbus TCP / IP protocol; the PLC controller is also connected to an acoustic monitoring module, which includes an underwater microphone and a spectrum analyzer, and is used to detect the abnormal noise spectrum during the operation of the water turbine (1). When a continuous broadband noise of 500 Hz - 2 kHz appears in the abnormal noise spectrum, it is determined as blade cavitation corrosion, so as to automatically trigger a maintenance alarm and reduce the rotational speed of the water turbine (1) to a safety threshold, where the safety threshold includes a lower threshold ≥ 15 rpm to ensure that the water turbine (1) overcomes the static friction resistance and avoids sediment attachment on the blade (6) caused by low flow velocity; an upper threshold ≤ 75 rpm to prevent cavitation corrosion and mechanical overload of the blade (6) under high flow velocity; an emergency shutdown threshold ≥ 80 rpm to trigger the hard-wired protection circuit of the PLC controller, cut off the water flow, and start mechanical braking.

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