Split-flow step-by-step coagulation device and digital intelligent coagulation control method thereof

Abstract

The invention discloses a split-flow step-by-step coagulation device and a digital intelligent coagulation control method thereof, and belongs to the field of water treatment.The split-flow step-by-step coagulation device comprises an upper mixing chamber and a lower mixing chamber which are communicated through a guide cylinder, the upper mixing chamber is communicated with a split-flow pipe through a mixing pipe, the split-flow pipe is communicated with a water inlet pipe, and one side of the lower mixing chamber is communicated with the water inlet pipe through a Venturi pipe; the other side of the lower mixing chamber is communicated with a water outlet pipe; the Venturi tube is provided with a shunt regulating valve, the shunt tube is provided with a flow velocity tester, the mixing tube is provided with a dosing tube, the upper mixing chamber and the guide cylinder are internally provided with a stirring impeller and a thrust impeller respectively, the lower mixing chamber is internally provided with a guide tube communicated with the guide cylinder, and the water outlet tube is provided with a flowing current sensor; according to the scheme, the hydraulic condition required by the optimal mixing effect is ensured, dynamic parameter adjustment is controlled through digital intelligent coagulation, GT optimized operation also ensures that the effluent turbidity of the sedimentation tank is stabilized below 1ntu for a long time, and the purposes of improving quality and efficiency, saving water and reducing emission, saving energy and reducing consumption are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a flow-dividing and step-by-step coagulation device and a digital intelligent coagulation control method thereof. Background Art

[0002] The coagulation process is the core process of water supply and drainage treatment, grey water treatment and part of sewage treatment, including coagulation and flocculation. Coagulation refers to the stirring and mixing stage of adding coagulant into water, and flocculation refers to the process of forming larger flocs by making micro flocs contact and collide with each other under the action of water flow after adding coagulant and fully mixing source water. The development of coagulation technology is the development of mixing process and flocculation process.

[0003] In the early stage of water treatment technology development, the importance of the mixing process was not fully recognized; in engineering, coagulants were simply added to the front end of the booster pump, and the mixing process was completed by the stirring effect of the water pump. This was the original mixing mode - water pump mixing. Water pump mixing causes serious corrosion to the water pump. Therefore, the coagulant was added to the pipeline and a certain length of pipeline was used to complete the mixing, which is called pipeline mixing. This mixing method is still in use. Waterfall mixing is a mixing method proposed based on the understanding of the intense mixing state of air and water, and its control parameters are empirical and perceptual. The emergence of mechanical stirring mixing tanks marks a certain understanding of the dynamic mechanism of mixed fluids. Researchers have proposed to use parameters that can characterize the turbulent state of the fluid in the mixing tank to control the effect of mechanical stirring mixing.

[0004] The commonly used coagulation technology in the water supply and drainage industry is to form polymers through the hydrolysis of coagulants. These large-particle polymers have a strong adsorption capacity for impurity colloids and can adsorb colloids within a certain distance and sink together. Physical coagulation includes self-coagulation and concentration flocculation in which large particles adsorb small particles and sink rapidly. Coagulation control technology refers to the use of technology and methods to accurately determine the optimal dosage of coagulants for thousands of tons of water, as well as the control method of coagulant addition to obtain the best mixing effect.

[0005] For a specific water treatment process system, the form and performance of the water purification structure are fixed. Coagulation control refers to timely adjustment of the dosage of coagulant to adapt to changes in factors such as source water quality, water volume, and coagulant efficiency, to ensure that the turbidity of the sedimentation water reaches the specified index; selecting different influencing factors as input parameters and determining the input parameters through different methods constitute various technical methods for coagulant dosing control; these methods can be classified from different perspectives.

[0006] According to the control method, it can be divided into: offline control, such as empirical visual method, potential method, etc., intermittent human intervention adjustment of the dosing conditions based on experimental or observation results; online control, that is, various automatic control methods, based on the results of online continuous monitoring of the controlled parameters, the control system continuously and automatically adjusts the dosage. Online control can be divided into: simple feedback control, feedforward control, composite control (feedforward-feedback control, cascade control) and other control methods.

[0007] According to the nature of the controlled parameters, it can be divided into: simulation method, which determines the dosage through a certain similar simulation relationship, including beaker experiment method, simulated filter method, simulated sedimentation tank method, etc.; water quality parameter method, which establishes an empirical model through apparent water quality parameters as the basis for controlling the dosage, such as mathematical simulation method, etc.; characteristic parameter method, this type of method uses the change of certain microscopic characteristics during the coagulation process as the basis for determining the dosage, including charge control methods such as potential method, colloid titration method, and streaming current method, as well as fluorescence method, pulsation parameter method, specific surface area method, etc.; effect evaluation method, which uses the actual effect observed macroscopically after dosing and coagulation as the basis for adjusting the dosage, including empirical visual method, turbidity measurement method, etc.

[0008] At present, the most commonly used digital intelligent coagulation control methods in domestic water purification plants are the empirical visual method, the beaker test method, and the more advanced streaming current method.

[0009] All the above-mentioned coagulation control technologies have a major flaw, which is that they ignore the important role of mixing process facilities and mixing efficiency in coagulation control. This is a difficult problem to solve in coagulation control technology in the water supply and drainage industry at home and abroad; because no matter how advanced and accurate the mixing effect detection methods and facilities and equipment are, the various data that can represent the mixing effect detected are only the mixing effect data obtained in the online operation of various mixing processes, facilities, and equipment. For example, the flow current sensor is the most advanced mixing effect detection instrument at home and abroad. The mixing effect data it detects is real and accurate at present, but the flow current sensor itself cannot change the mixing effect. It only uses the changes in certain microscopic characteristics in the coagulation process as the basis for determining the dosage. To discuss it in another way, the offline control of coagulation technology is a human intervention adjustment to determine the basis for the dosage. The simulation method of coagulation control technology relies on instruments and facilities for measurement to determine the basis for the dosage. In short, the current coagulation control technology can only achieve the best mixing effect by adjusting the amount of coagulant, which is unscientific and not rigorous; because according to the coagulant coagulation mechanism and coagulation dynamic mechanism, the hydraulic conditions and mixing residence time and other requirements that meet the coagulant coagulation mechanism and coagulation dynamic mechanism of the existing mixing processes, facilities, and equipment during the mixing process cannot meet the coagulant coagulation mechanism and coagulation dynamic mechanism requirements. There are many problems in simply relying on adjusting the amount of coagulant added to improve the mixing effect. Summary of the invention

[0010] In view of the above-mentioned deficiencies in the prior art, the present invention provides a diversion and step-by-step coagulation device and a digital intelligent coagulation control method thereof, which solve the problems of poor coagulation effect, poor adaptability to changes in external factors, poor quality improvement and efficiency enhancement, and poor consumption and emission reduction effects of the existing coagulation devices.

[0011] To achieve the above purpose, the technical solution adopted by the present invention is:

[0012] In the first aspect, a flow-dividing and step-by-step coagulation device is provided, which comprises an upper mixing chamber and a lower mixing chamber connected through a guide tube, the upper mixing chamber is connected to the flow-dividing pipe through a mixing tube, the flow-dividing pipe is connected to the water inlet pipe, one side of the lower mixing chamber is connected to the water inlet pipe through a venturi tube, and the other side of the lower mixing chamber is connected to the water outlet pipe; a flow-dividing regulating valve is arranged on the venturi tube, a flow velocity tester is arranged on the flow-dividing pipe, a dosing pipe is arranged on the mixing pipe, the dosing pipe is connected to an automatic dosing device, a guide plate is arranged in the mixing tube, and stirring devices are arranged in the upper mixing chamber and the guide tube, respectively. The mixing impeller and the thrust impeller are all connected with the permanent magnet mixing motor in transmission. A guide pipe connected with the guide cylinder is arranged in the lower mixing chamber. The water inlet pipe is provided with an inlet pH sensor, a turbidity sensor and a flow sensor. The water outlet pipe is provided with an outlet pH sensor and a flow current sensor. The shunt regulating valve, flow rate tester, automatic dosing equipment, permanent magnet mixing motor, inlet pH sensor, outlet pH sensor, turbidity sensor, flow sensor and flow current sensor are all electrically connected with the digital intelligent coagulation control system.

[0013] Furthermore, the digital intelligent coagulation control system includes: a regulating valve actuator, an automatic dosing actuator and a motor actuator electrically connected to the diversion regulating valve, the automatic dosing equipment and the permanent magnet stirring motor respectively, and a flow current controller electrically connected to the flow current sensor; the regulating valve actuator, the motor actuator and the flow rate tester are all electrically connected to the first PLC controller; the flow current controller is electrically connected to the first PLC controller and the PDI controller respectively, and the PDI controller is electrically connected to the automatic dosing actuator.

[0014] Furthermore, the guide plate is spiral, the extension direction of the port of the dosing tube is the same as the water flow direction in the mixing tube, a diffusion cone plate is arranged in the gap at the port of the dosing tube, and the cone tip of the diffusion cone plate is arranged facing the port of the dosing tube.

[0015] Furthermore, the diverter regulating valve is arranged at the middle throat of the venturi tube, a plurality of diverter holes are opened on the gate plate of the diverter regulating valve, and a flow rate tester is arranged at the connection end of the diverter tube and the mixing tube.

[0016] Furthermore, 2.5 times the sum of the cross-sectional areas of the plurality of diverter holes is equal to the cross-sectional area of ​​the diverter tube.

[0017] Furthermore, an automatic exhaust valve is provided on the top of the upper mixing chamber.

[0018] In a second aspect, a digital intelligent coagulation control method for a split-flow and step-by-step coagulation device is provided, which includes a coagulant coagulation method, the steps of which are:

[0019] S1: Coagulant mixing process: Coagulant is added through the dosing pipe, and the flow rate of the diversion pipe is controlled by the diversion regulating valve, so that the coagulant is quickly diffused into the source water in the mixing pipe;

[0020] S2: Partial and complete destabilization process of coagulant: By controlling the speed of the permanent magnet stirring motor, the coagulant is mixed in the upper mixing chamber by a combination of stirring and water power, the coagulant is rapidly hydrolyzed, and the impurity colloidal particles are destabilized. Then, under the mixing action of the thrust impeller, the impurity colloidal particles are completely destabilized in the guide tube;

[0021] S3: Coagulant heterogeneous flocculation process: By designing the structural parameters of the guide tube, the fluid is acted upon by the thrust impeller to generate axial flow and axial circulation in the guide tube, which then intersects and merges with the radial flow generated by the Venturi tube. The water body is made to flow in a three-dimensional state in the lower mixing chamber, forming a high-intensity mixing condition and replacing the Brownian motion, ensuring that the destabilized impurity colloid particles are quickly aggregated and the flocs are in a state of small particles that are not easily broken.

[0022] Furthermore, the mixing intensity G value of the coagulant mixing process is ≥600-1000-1, and the residence time T is <0.2s; the mixing intensity G value of the coagulant partial destabilization and complete destabilization process is ≥3000-1, and the residence time T is <0.2s; the mixing intensity G value of the coagulant heterogeneous flocculation process is ≤2000-1, and the residence time T is ≥6s.

[0023] In a third aspect, a digital intelligent coagulation control method for a split-flow and step-by-step coagulation device is provided, which includes a double closed-loop digital intelligent coagulation control method, the steps of which are:

[0024] A1: Set the parameter range of the flow velocity of the diverter pipe, the parameter range of the permanent magnetic stirring motor speed, the parameter range and optimal value of the streaming current response value, and the initial dosage of the coagulant;

[0025] A2: According to the changes of the flow rate tester, the flow regulating valve is controlled to automatically adjust until the flow rate of the flow pipe is stabilized within the corresponding parameter range;

[0026] A3: monitor the change of the flowing current response value, control the speed of the permanent magnet stirring motor to automatically adjust within the corresponding parameter setting range, until the flowing current response value is close to the optimal value to the maximum extent. If the flowing current response value at this time is within the corresponding parameter setting range, the execution ends, otherwise, execute step A4;

[0027] A4: When the flowing current response value is higher than the upper limit of the parameter setting range, the automatic dosing device is controlled to reduce the dosage of the coagulant until the flowing current response value changes dynamically, and the process returns to step A3; when the flowing current response value is lower than the lower limit of the parameter setting range, step A5 is executed;

[0028] A5: When the inlet flow rate is greater than the rated inlet flow rate or when the source water turbidity is greater than the normal turbidity, execute step A6; when the temperature and turbidity of the source water are lower than the normal temperature and the normal turbidity respectively, execute step A7; when the pH value of the source water is greater than 8, execute step A8;

[0029] A6: Control the automatic dosing device to increase the dosage of the coagulant until the streaming current response value changes dynamically, and return to step A3;

[0030] A7: Return to step A3 first, and after step A3 is completed, if the flowing current response value is still lower than the lower limit of the parameter setting range, execute step A6;

[0031] A8: Add carbon dioxide to the source water until the pH value of the source water is no more than 8; or lower the lower limit of the parameter setting range until the flow current response value is within the new parameter setting range; and return to step A3.

[0032] Furthermore, step A1 specifically includes: the parameter range of the flow velocity of the diversion pipe is 1.2 to 1.5 m / s; the parameter range of the permanent magnet stirring motor speed is 300 to 520 r / min; the parameter range of the flow current response value when the source water quality meets the normal standard is -40 to -10.

[0033] The beneficial effects of the present invention are:

[0034] 1. This scheme diverts the inlet water of the inlet pipe, and then realizes the cross-convergence of radial flow and axial flow in the lower mixing chamber. Its purpose is to make full use of the motive force of the inlet fluid and add mechanical stirring mixed power, so as to meet the mixing time (T) and mixing intensity (G) requirements of rapid diffusion, rapid hydrolysis, and complete destabilization of the coagulant, thereby realizing the diversion and step-by-step mixing of the coagulant, solving the problem that the existing coagulation device is difficult to meet the mixing intensity and mixing time required for each process of the coagulant coagulation mechanism; at the same time, the G value and T value of the coagulant coagulation process can be adjusted by the opening of the diversion regulating valve and the speed of the permanent magnet stirring motor, and then the speed of the permanent magnet stirring motor is reversely adjusted by the change of the flow current response value (mixing effect), so as to realize the GT optimized combined operation.

[0035] 2. This scheme adopts a double closed-loop digital intelligent coagulation control method, in which the first closed loop is: by adjusting the flow rate of the diversion pipe and the speed of the permanent magnet stirring motor, the diversion and step coagulation device is adjusted to the optimal hydraulic conditions and optimal retention time that meet the coagulation mechanism requirements of the coagulant, and on the basis of the optimal hydraulic conditions and optimal retention time, the GT optimization combination operation is performed; the second closed loop is: on the basis of the former achieving the best mixing efficiency, the coagulant dosage is adjusted in time to achieve the best mixing effect; the two closed-loop controls overlap with each other, with the same goals, but they play their respective roles independently, with clear cause-and-effect relationships, safe and reliable, simple and easy to operate; the coagulant efficacy is fully exerted to the extreme, and the drug consumption is saved to the maximum extent; it solves the problem that the existing coagulation control technology relies solely on adjusting the coagulant dosage to change the coagulation effect, and the limitations are large, and the goals and requirements of improving quality, increasing efficiency, reducing consumption and reducing emissions in the water treatment industry are truly achieved.

[0036] 3. This scheme not only ensures the hydraulic conditions and mixing efficiency required for the best mixing effect of the coagulation device, but also accurately determines the optimal dosage of the coagulant through the optimization of the diversion distribution coagulation device and the digital intelligent coagulation control method; and the optimal dosage can be quickly and accurately obtained under trial operation within a certain period of time, so that the efficacy of the coagulant can be brought to the extreme and the drug consumption can be saved to the maximum extent; the key is that when various external factors such as raw water quality, water volume changes, low temperature and low turbidity affect the coagulation effect, adaptive parameter adjustments can be made to ensure that the turbidity of the effluent from the sedimentation tank is stable below 1NTU for a long time, which means that the foundation is laid for reducing the burden of the filter water treatment process in the future, reducing the frequency of filter backwashing by more than 1 times, saving more than 50% of backwashing water, reducing sewage discharge by more than 50%, saving more than 30% of coagulant per thousand tons of water, and reducing electricity consumption by more than 5% per thousand tons of water.

[0037] 4. The coagulation device of this scheme has the dual functions of mixing and heterogeneous flocculation. The heterogeneous flocculation process is mainly caused by Brownian motion, which gradually weakens with the increase of particle size. When the particle size grows to a certain size, the Brownian motion no longer works; therefore, this scheme incorporates the heterogeneous flocculation process into the coagulation device, so that the heterogeneous flocculation process is accelerated by high-intensity mixing means. This means can effectively promote the collision and aggregation of particles, thereby achieving an excellent mixing effect.

[0038] 5. This solution not only ensures the hydraulic conditions required for the coagulant mixing mechanism by setting the flow rate adjustment range and performing digital intelligent control, but its important role also lies in that when the water inlet flow changes, especially when the change exceeds 60%, the coagulant coagulation effect is not affected; the setting of the diversion hole on the gate plate of the diversion regulating valve can effectively ensure the formation of three-dimensional fluid in the lower mixing chamber during low flow operation, thereby ensuring its mixing intensity.

[0039] 6. When external factors such as source water quality, water volume, low temperature and turbidity, and pH value that affect the coagulation effect of the coagulant occur, the control system converts these sensor signals into digital control, and dynamically adjusts and feedback controls the mixing intensity, diversion pipe flow rate, flow current response value, coagulant dosage control and other parameters of the coagulation device in a timely manner to reduce or eliminate the impact of these external factors on the coagulation effect of the coagulant.

[0040] 7. In this solution, after the coagulant is added, the flowing current detector can detect the mixing effect within 10 seconds and the coagulant dosage can be accurately determined within 10 minutes, which greatly guarantees the safe operation of the water treatment process in the water plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the structure of the split-flow and step-by-step coagulation device.

[0042] Figure 2 This is the flow chart of the digital intelligent coagulation control method of this scheme.

[0043] Figure 3 Schematic diagram of the structure of the mixing tube.

[0044] Figure 4 It is a structural schematic diagram of the diverter control valve.

[0045] Among them, 1. guide tube, 2. upper mixing chamber, 3. lower mixing chamber, 4. mixing tube, 5. diverter pipe, 6. water inlet pipe, 7. venturi tube, 8. water outlet pipe, 9. diverter regulating valve, 10. flow rate tester, 11. dosing tube, 12. guide plate, 13. stirring impeller, 14. thrust impeller, 15. permanent magnet stirring motor, 16. guide tube, 17. water inlet PH sensor, 18. water outlet PH sensor, 19. flow current sensor, 20. diffusion cone plate, 21. diverter hole, 22. automatic exhaust valve, 23. flow sensor. DETAILED DESCRIPTION

[0046] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0047] like Figures 1 to 4 As shown, the split-flow and step-by-step coagulation device of the present scheme comprises an upper mixing chamber 2 and a lower mixing chamber 3 connected through a guide tube 1, the upper mixing chamber 2 is connected to a split pipe 5 through a mixing pipe 4, the split pipe 5 is connected to a water inlet pipe 6, one side of the lower mixing chamber 3 is connected to the water inlet pipe 6 through a venturi tube 7, and the other side of the lower mixing chamber 3 is connected to a water outlet pipe 8;

[0048] The venturi tube 7 is provided with a flow regulating valve 9, the flow dividing tube 5 is provided with a flow velocity tester 10, the mixing tube 4 is provided with a dosing tube 11, the dosing tube 11 is connected with an automatic dosing device, a guide plate 12 is provided in the mixing tube 4, an automatic exhaust valve 22 is provided at the top of the upper mixing chamber 2, a stirring impeller 13 and a thrust impeller 14 are provided in the upper mixing chamber 2 and the guide tube 1, respectively, the stirring impeller 13 and the thrust impeller 14 are both connected with a permanent magnet stirring motor 15, and the lower mixing chamber 3 is provided with a flow guide plate 12, and the upper mixing chamber 2 and the guide tube 1 are provided with a stirring impeller 13 and a thrust impeller 14, respectively, and the stirring impeller 13 and the thrust impeller 14 are connected with a permanent magnet stirring motor 15. A guide tube 16 connected to the guide tube 1 is arranged inside, an inlet pH sensor 17 and a flow sensor 23 are arranged on the water inlet pipe 6, and an outlet pH sensor 18 and a flow current sensor 19 are arranged on the water outlet pipe 8; the diversion regulating valve 9, flow rate tester 10, automatic dosing equipment, permanent magnet stirring motor 15, inlet pH sensor 17, outlet pH sensor 18, flow current sensor 19 and flow sensor 23 are all electrically connected to the digital intelligent coagulation control system.

[0049] Among them, the digital intelligent coagulation control system includes: a regulating valve actuator, an automatic dosing actuator and a motor actuator electrically connected to the diversion regulating valve 9, the automatic dosing equipment and the permanent magnet stirring motor 15 respectively, and a flow current controller electrically connected to the flow current sensor 19, the regulating valve actuator, the motor actuator and the flow rate tester 10 are all electrically connected to the first PLC controller; the flow current controller is electrically connected to the first PLC controller and the PDI controller respectively, and the PDI controller is electrically connected to the automatic dosing actuator; the digital intelligent coagulation control system of this scheme is mainly used for automatic identification of sensor information, system reading, data analysis, information conversion, detection and collection, equipment monitoring and alarm, dynamic parameter adjustment, feedback control, etc.

[0050] The diverter regulating valve 9 is arranged at the middle throat of the venturi tube 7, and a plurality of diverter holes 21 are opened on the gate plate of the diverter regulating valve 9, and 2.5 times of the sum of the cross-sectional areas of the plurality of diverter holes 21 is equal to the cross-sectional area of ​​the diverter tube 5; the flow rate tester 10 is arranged at the connecting end of the diverter tube 5 and the mixing tube 4.

[0051] This solution diverts the incoming water from the water inlet pipe 6, and then realizes the cross-convergence of radial flow and axial flow in the lower mixing chamber 3. Its purpose is to make full use of the motive force of the incoming water fluid and add mechanical stirring mixed power, so as to meet the mixing time (T) and mixing intensity (G) requirements for rapid diffusion, rapid hydrolysis, and complete destabilization of the coagulant, thereby realizing the diversion and step-by-step mixing of the coagulant, solving the problem that the existing coagulation device is difficult to meet the mixing intensity and mixing time required for each process of the coagulant coagulation mechanism.

[0052] Among them, the diversion process specifically includes: setting the upper and lower flow rates of the diversion pipe 5 according to the optimal flow rate of the diversion pipe 5; when the flow rate of the diversion pipe 5 exceeds the upper limit of the flow rate of the diversion pipe 5 or is lower than the lower limit of the flow rate of the diversion pipe 5, timely adjusting the diversion regulating valve 9 so that the flow rate of the diversion pipe 5 is always maintained at the optimal setting state; such a setting can always maintain the flow demand of the diversion pipe 5 when the water volume of the water inlet pipe 6 changes, so that the mixing effect is not affected by the change of the water inlet flow rate; when the water inlet pipe 6 is running at the rated flow rate or greater than the rated flow rate, the diversion regulating valve 9 is in a fully open state; when the main water inlet volume is lower than 35% of the rated flow rate, the diversion regulating valve 9 is in a fully closed state, but through the several diversion holes 21 on the gate plate of the diversion regulating valve 9, 10% of the water inlet volume still enters the lower mixing chamber 3 and 25% of the water inlet volume enters the diversion pipe 5 and the upper mixing chamber 2, so that the mixing hydraulic conditions of the mixing device can meet the coagulant coagulation mechanism requirements to the greatest extent.

[0053] The present invention also provides a digital intelligent coagulation control method for a split-flow and step-by-step coagulation device, which includes a coagulant coagulation method and a double closed-loop digital intelligent coagulation control method, wherein the coagulant coagulation method includes:

[0054] S1: Coagulant mixing process: coagulant is added through the dosing tube 11, and the flow rate of the shunt tube 5 is controlled by the shunt regulating valve 9, so that the coagulant is quickly diffused into the source water in the mixing tube 4; the mixing intensity G value of the coagulant mixing process is ≥600-1000-1, and the retention time T is less than 0.2s; correspondingly, the guide plate 12 of this scheme is spiral, the extension direction of the port of the dosing tube 11 is the same as the water flow direction in the mixing tube 4, and a diffusion cone plate 20 is arranged in the gap at the port of the dosing tube 11, and the cone tip of the diffusion cone plate 20 is arranged opposite to the port of the dosing tube 11; such an arrangement enables the liquid sprayed from the dosing tube 11 to be rapidly diffused under the action of the diffusion cone plate 20, and the rapid mixing of the coagulant is achieved under the action of the spiral guide plate 12; the coagulant mixing process uses the flow velocity power to achieve hydraulic mixing, and the mixing intensity G value and the retention time T value of the process can be calculated by the flow velocity and the structural parameters of the mixing tube 4;

[0055] S2: partial destabilization and complete destabilization process of coagulant: by controlling the rotation speed of the permanent magnet stirring motor 15, the coagulant is subjected to a combined mixing of stirring and water power in the upper mixing chamber 2, the coagulant is rapidly hydrolyzed, and the impurity colloidal particles are destabilized, and then under the mixing action of the thrust impeller 14, the impurity colloidal particles are completely destabilized in the guide tube 1; the mixing intensity G value of the partial destabilization and complete destabilization process of the coagulant is ≥3000-1, and the retention time T is <0.2s; specifically, the mixing intensity G value of the process can be calculated by the rotation speed of the permanent magnet stirring motor 15, and the retention time T value can be calculated by the flow rate, the structural parameters of the upper mixing chamber 2 and the guide tube 1;

[0056] S3: Coagulant heterogeneous flocculation process: by designing the structural parameters of the flow guide tube 16, the fluid is acted upon by the thrust impeller 14, generating axial flow and axial circulation in the flow guide tube 16, and then intersecting and merging with the radial flow generated by the venturi tube 7, so that the water body is in a three-dimensional flow state in the lower mixing chamber 3, forming a high-intensity mixing condition, and replacing the Brownian motion, ensuring that the destabilized impurity colloid particles are quickly aggregated and the flocs are in a state of small particles that are not easily broken; the mixing intensity G value of the coagulant heterogeneous flocculation process is ≤2000-1, and the residence time T is ≥6s; specifically, the mixing intensity G value of the process can be calculated by the rotation speed of the permanent magnet stirring motor 15, and the residence time T value can be calculated by the flow rate, the volume of the flow guide tube 16 and other structural parameters.

[0057] The mixing intensity G value of this scheme is adjustable; the water power + mechanical stirring power obtained by the split flow mixing technology is used to achieve strong and rapid mixing in a small volume; the water power uses the fluid flow rate detected by the flow rate detector, and the flow rate is adjusted by the flow control valve. The mixing intensity G value generated by the hydraulic stirring power is adjustable, and the permanent magnet stirring motor 15 uses a variable frequency motor with a speed adjustment range of 200-600 rpm; the retention time T value is adjustable. If the rated water flow rate of the mixer is less than 70% during actual operation, it will cause the flow rate of the fluid in the split pipe 5 to increase. If the flow rate is too slow, the mixing intensity will be reduced and the retention time will be prolonged, which will fail to meet the coagulation mechanism of the coagulant and the strong and rapid mixing requirements during the mixing process. Therefore, a flow rate detector is used to detect the flow rate of the mixing chamber 2 on the diversion pipe 5, and the water flow rate of the flow regulating valve is adjusted according to the flow rate to meet the strong and rapid mixing requirements of the coagulant mixing process. Therefore, when the inlet flow rate changes, the retention time can still meet the requirements of the coagulant coagulation mechanism. The mixing effect is not affected by changes in water volume, and the mixer has a strong adaptability to changes in external environmental factors.

[0058] In summary, the G value and T value in the coagulant coagulation process of this scheme can be adjusted by the opening of the diversion regulating valve 9 and the speed of the permanent magnet stirring motor 15, and then the speed of the permanent magnet stirring motor 15 is reversely adjusted through the change of the flow current response value (mixing effect), so as to meet the mixing intensity G value and the retention time T value required for coagulant mixing, destabilization, and heterogeneous flocculation, so as to realize the GT optimized combined operation.

[0059] The double closed-loop digital intelligent coagulation control method includes:

[0060] A1: setting the parameter range of the flow velocity of the diverter pipe 5, the parameter range of the speed of the permanent magnetic stirring motor 15, the parameter range and the optimal value of the streaming current response value and the initial dosage of the coagulant;

[0061] A2: According to the changes of the flow rate tester 10, the flow dividing regulating valve 9 is controlled to automatically adjust until the flow rate of the flow dividing pipe 5 is stabilized within the corresponding parameter range;

[0062] A3: monitor the change of the flowing current response value, control the rotation speed of the permanent magnet stirring motor 15 to automatically adjust within the corresponding parameter setting range, until the flowing current response value is close to the optimal value to the maximum extent. If the flowing current response value at this time is within the corresponding parameter setting range, the execution ends, otherwise execute step A4;

[0063] A4: When the flowing current response value is higher than the upper limit of the parameter setting range, the automatic dosing device is controlled to reduce the dosage of the coagulant until the flowing current response value changes dynamically, and the process returns to step A3; when the flowing current response value is lower than the lower limit of the parameter setting range, step A5 is executed;

[0064] A5: When the inlet flow rate is greater than the rated inlet flow rate or when the source water turbidity is greater than the normal turbidity, execute step A6; when the temperature and turbidity of the source water are lower than the normal temperature and the normal turbidity respectively, execute step A7; when the pH value of the source water is greater than 8, execute step A8;

[0065] A6: Control the automatic dosing device to increase the dosage of the coagulant until the streaming current response value changes dynamically, and return to step A3;

[0066] A7: Return to step A3 first, and after step A3 is completed, if the flowing current response value is still lower than the lower limit of the parameter setting range, execute step A6;

[0067] A8: Add carbon dioxide to the source water until the pH value of the source water is no more than 8; or lower the lower limit of the parameter setting range until the flow current response value is within the new parameter setting range; and return to step A3.

[0068] Among them, step A1 specifically includes: the parameter range of the flow velocity of the diverter pipe 5 is 1.2-1.5m / s. When the equipment is running, if the flow velocity of the diverter pipe 5 exceeds 1.5m / s, water resistance of the main water inlet pipe 6 will be generated, so the diverter regulating valve 9 needs to be automatically regulated to reduce the flow velocity; when the flow velocity of the diverter pipe 5 is lower than 1.2m / s, it will affect the hydraulic mixing effect in the mixing pipe 4, so the diverter regulating valve 9 needs to be automatically regulated to increase the flow velocity so that the flow velocity of the diverter pipe 5 is always within the set parameter range; according to the change of the flow current response value, and considering the flow change, low temperature and low Considering the external factors that affect the mixing effect, such as turbidity, and the influence of mixing intensity and residence time on the mixing effect and the change of the flowing current response value, the speed parameter range of the permanent magnet stirring motor 15 is 300-520r / min; considering the relationship between the pH value and the flowing current response value and the change of the pH value, the parameter is set to -60--10 under the premise of ensuring the coagulation effect; it should be noted that the flowing current response value is used as the colloid polymerization sedimentation effect (mixing effect), and the best mixing effect is when the flowing current response value = ±0, but according to the relationship between the flowing current response value and the pH value, theoretically It is impossible to achieve this because the pH value of the source water is uncontrollable. According to practical operation, the upper limit of the flowing current response value is defined as -10 and the lower limit is -60, and the optimal value of the flowing current response value is set in between; when the pH value of the source water is greater than 8, after the addition of carbon dioxide, the pH value is reduced to 7.6, and the flowing current response value can be adjusted to ±0, which means that the ± charges in the water can be fully integrated and offset, and the efficacy of the medicine can reach 100%; therefore, when the source water quality is normal, the flowing current response value is generally controlled between -10 and -40; when the source water quality changes or the Ph value is greater than 8, the flowing current response value is controlled between -10 and -40. The response value is generally controlled between -20 and -60. When the equipment is running, when the flowing current response value is higher than the upper limit, the dosage of the coagulant is automatically reduced; when the flowing current response value is lower than the lower limit, the dosage of the coagulant is automatically increased; under this premise, the turbidity of the effluent from the sedimentation tank can be stabilized below 1NTU for a long time, or even below 0.3NTU for a long time, the backwash frequency of the filter can be extended by more than double, water saving by more than 50%, emissions reduction by more than 50%, electricity consumption per thousand tons of water reduced by 5%, and chemical consumption per thousand tons of water reduced by 30% (compared with mechanical mixing tanks), while reducing the operation and maintenance costs of the filter.

[0069] This scheme adopts a double closed-loop digital intelligent coagulation control method, in which the first closed loop is: by adjusting the flow velocity of the diversion pipe 5 and the speed of the permanent magnet stirring motor 15, the diversion and step-by-step coagulation device is adjusted to the optimal hydraulic conditions and optimal retention time that meet the coagulation mechanism requirements of the coagulant, and on the basis of the optimal hydraulic conditions and optimal retention time, GT optimization combination operation is performed.

[0070] The second closed loop is: on the basis of achieving the best mixing efficiency in the former, the optimal dosage of coagulant for one thousand tons of water is finally determined by adjusting the dosage of coagulant in time to achieve the best mixing effect; the two closed-loop controls overlap with each other and have the same goals, but they play their respective roles independently, with clear cause-and-effect relationships, safety, reliability, and simplicity; the efficacy of the coagulant is fully exerted to the extreme, and drug consumption is saved to the maximum extent; it solves the problem that the existing coagulation control technology relies solely on adjusting the dosage of coagulant to change the coagulation effect, and the limitations are large, and the goals and requirements of improving quality, increasing efficiency, reducing consumption, and reducing emissions in the water treatment industry are truly achieved.

[0071] This scheme is based on the application practice experience and the demand for water treatment mixing effect. In order to avoid the electronic signal and the coagulant dosage signal feedback being out of sync, resulting in frequent adjustments of the coagulant dosage equipment, and even causing unsafe factors such as equipment damage and failure, this scheme abandons the typical response value and set value comparison method commonly used in current water plants, and adjusts the dosage output according to a certain control strategy, designs a method for adjusting the safe area of ​​the flow current response value, and the automatic dosing equipment does not make any dosage adjustments in this area, so that the automatic dosing equipment does not respond to frequent adjustments due to small and frequent changes in the flow current response value, thereby ensuring water quality and safe operation; in addition, under the same source water quality conditions in the same water plant, the flow current sensor 19 can be used to control coagulation by dragging N diversion and step-by-step coagulation devices, that is, the data of the precise coagulant dosage of 1,000 tons of water is determined through a second closed loop, and is transmitted to the control program of other automatic dosing equipment in real time, and coagulation control is performed in a proportional dosage manner.

[0072] To sum up, this scheme not only ensures the hydraulic conditions required for the best mixing effect, but also accurately determines the optimal dosage of the coagulant through the coagulant coagulation method and the double closed-loop digital intelligent coagulation control method; and the optimal dosage can be quickly and accurately obtained under trial operation within a certain period of time, so that the efficacy of the coagulant can be brought to the extreme and the drug consumption can be saved to the maximum extent; at the same time, under the influence of various factors such as the source water quality of the water inlet pipe 6 and the water flow changes, adaptive adjustments can be made to ensure the water quality of the outlet water.

Claims

1. A split-flow and step-by-step coagulation device, It is characterized in that It comprises an upper mixing chamber and a lower mixing chamber connected through a guide tube, wherein the upper mixing chamber is connected to a diverter pipe through a mixing tube, the diverter pipe is connected to a water inlet pipe, one side of the lower mixing chamber is connected to the water inlet pipe through a venturi tube, and the other side of the lower mixing chamber is connected to a water outlet pipe; The venturi tube is provided with a shunt regulating valve, the shunt pipe is provided with a flow rate tester, the mixing tube is provided with a dosing pipe, the dosing pipe is connected to an automatic dosing device, a guide plate is provided in the mixing tube, a stirring impeller and a thrust impeller are provided in the upper mixing chamber and the guide cylinder respectively, the stirring impeller and the thrust impeller are both connected to the permanent magnet stirring motor by transmission, a guide pipe connected to the guide cylinder is provided in the lower mixing chamber, a water inlet PH sensor, a turbidity sensor and a flow sensor are provided on the water inlet pipe, and a water outlet PH sensor and a flow current sensor are provided on the water outlet pipe; The diversion regulating valve, flow rate tester, automatic dosing equipment, permanent magnet stirring motor, water inlet pH sensor, water outlet pH sensor, turbidity sensor, flow sensor and flow current sensor are all electrically connected to the digital intelligent coagulation control system.

2. The split-flow and step-by-step coagulation device according to claim 1, It is characterized in that The digital intelligent coagulation control system comprises: A regulating valve actuator, an automatic dosing actuator and a motor actuator electrically connected to the diversion regulating valve, the automatic dosing device and the permanent magnetic stirring motor respectively, wherein the regulating valve actuator, the motor actuator and the flow rate tester are all electrically connected to the first PLC controller; A flow current controller electrically connected to the flow current sensor, wherein the flow current controller is electrically connected to the first PLC controller and the PDI controller respectively, and the PDI controller is electrically connected to the automatic dosing actuator.

3. The split-flow and step-by-step coagulation device according to claim 1, It is characterized in that The guide plate is spiral-shaped, the extension direction of the port of the dosing tube is the same as the water flow direction in the mixing tube, a diffusion cone plate is arranged in the gap at the port of the dosing tube, and the cone tip of the diffusion cone plate is arranged facing the port of the dosing tube.

4. The split-flow and step-by-step coagulation device according to claim 1, It is characterized in that The diversion regulating valve is arranged at the middle throat of the venturi tube, a plurality of diversion holes are opened on the gate plate of the diversion regulating valve, and the flow velocity tester is arranged at the connection end of the diversion tube and the mixing tube.

5. The split-flow and step-by-step coagulation device according to claim 4, It is characterized in that 2.5 times the sum of the cross-sectional areas of the plurality of diverter holes is equal to the cross-sectional area of ​​the diverter tube.

6. The split-flow and step-by-step coagulation device according to claim 1, It is characterized in that An automatic exhaust valve is arranged on the top of the upper mixing chamber.

7. A digital intelligent coagulation control method using the split-flow and step-by-step coagulation device according to any one of claims 1 to 6, It is characterized in that The invention comprises a coagulant coagulation method, the steps of which are: S1: Coagulant mixing process: Coagulant is added through the dosing pipe, and the flow rate of the diversion pipe is controlled by the diversion regulating valve, so that the coagulant is quickly diffused into the source water in the mixing pipe; S2: Partial and complete destabilization process of coagulant: By controlling the speed of the permanent magnet stirring motor, the coagulant is mixed in the upper mixing chamber by a combination of stirring and water power, the coagulant is rapidly hydrolyzed, and the impurity colloidal particles are destabilized. Then, under the mixing action of the thrust impeller, the impurity colloidal particles are completely destabilized in the guide tube; S3: Coagulant heterogeneous flocculation process: By designing the structural parameters of the guide tube, the fluid is acted upon by the thrust impeller to generate axial flow and axial circulation in the guide tube, which then intersects and merges with the radial flow generated by the Venturi tube. The water body is made to flow in a three-dimensional state in the lower mixing chamber, forming a high-intensity mixing condition and replacing the Brownian motion, ensuring that the destabilized impurity colloid particles are quickly aggregated and the flocs are in a state of small particles that are not easily broken.

8. The digital intelligent coagulation control method of the split-flow and step-by-step coagulation device according to claim 7, It is characterized in that The mixing intensity G value of the coagulant mixing process is ≥600-1000-1, and the residence time T is <0.2s; the mixing intensity G value of the coagulant partial destabilization and complete destabilization process is ≥3000-1, and the residence time T is <0.2s; the mixing intensity G value of the coagulant heterogeneous flocculation process is ≤2000-1, and the residence time T is ≥6s.

9. A digital intelligent coagulation control method using the split-flow and step-by-step coagulation device according to any one of claims 1 to 6, It is characterized in that The invention comprises a double closed-loop digital intelligent coagulation control method, the steps of which are: A1: Set the parameter range of the flow velocity of the diverter pipe, the parameter range of the permanent magnetic stirring motor speed, the parameter range and optimal value of the streaming current response value, and the initial dosage of the coagulant; A2: According to the changes of the flow rate tester, the flow regulating valve is controlled to automatically adjust until the flow rate of the flow pipe is stabilized within the corresponding parameter range; A3: monitor the change of the flowing current response value, control the speed of the permanent magnet stirring motor to automatically adjust within the corresponding parameter setting range, until the flowing current response value is close to the optimal value to the maximum extent. If the flowing current response value at this time is within the corresponding parameter setting range, the execution ends, otherwise, execute step A4; A4: When the flowing current response value is higher than the upper limit of the parameter setting range, the automatic dosing device is controlled to reduce the dosage of the coagulant until the flowing current response value changes dynamically, and the process returns to step A3; when the flowing current response value is lower than the lower limit of the parameter setting range, step A5 is executed; A5: When the inlet flow rate is greater than the rated inlet flow rate or when the source water turbidity is greater than the normal turbidity, execute step A6; when the temperature and turbidity of the source water are lower than the normal temperature and the normal turbidity respectively, execute step A7; when the pH value of the source water is greater than 8, execute step A8; A6: Control the automatic dosing device to increase the dosage of the coagulant until the streaming current response value changes dynamically, and return to step A3; A7: Return to step A3 first, and after step A3 is completed, if the flowing current response value is still lower than the lower limit of the parameter setting range, execute step A6; A8: Add carbon dioxide to the source water until the pH value of the source water is no more than 8; or lower the lower limit of the parameter setting range until the flow current response value is within the new parameter setting range; and return to step A3.

10. The digital intelligent coagulation control method of the split-flow and step-by-step coagulation device according to claim 9, It is characterized in that Step A1 specifically includes: the parameter range of the flow velocity of the diversion pipe is 1.2 to 1.5 m / s; the parameter range of the permanent magnet stirring motor speed is 300 to 520 r / min; the parameter range of the flow current response value when the source water quality meets the normal standard is -40 to -10.

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