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CN-121974457-A - Polyaluminum chloride feeding control method based on raw water turbidity and water taking pump frequency

CN121974457ACN 121974457 ACN121974457 ACN 121974457ACN-121974457-A

Abstract

The invention provides a polyaluminium chloride feeding control method based on raw water turbidity and water taking pump frequency, relates to the technical field of automatic control of water treatment, and aims to solve the problems of hysteresis, inaccuracy and high energy consumption of traditional manual control and existing automatic control. According to the method, the turbidity value T of raw water and the running frequency value F of the water taking pump are monitored in real time, the raw water turbidity value T and the running frequency value F of the water taking pump are input into a preset control rule set for matching, a metering pump frequency control instruction is output, and a polyaluminium chloride dosing metering pump is driven to run. The control rule set defines the accurate mapping relation between the water taking pump frequency and the target frequency of the metering pump in different turbidity intervals. The invention converts complex nonlinear control into efficient table lookup operation, has rapid response and accurate control, not only realizes accurate matching of the adding amount with water quality and water quantity and improves the coagulation effect, but also avoids medicament waste and energy consumption increase, has clear system logic and high reliability, and is suitable for automatic and accurate adding of polyaluminium chloride in a water works.

Inventors

  • CHEN JINYONG
  • CHEN CHUN
  • Lv Chenkai
  • LI YING
  • TIAN HONGQIANG
  • Zhan Haodong

Assignees

  • 长江生态环保集团有限公司

Dates

Publication Date
20260505
Application Date
20260129

Claims (10)

  1. 1. The polyaluminum chloride feeding control method based on the turbidity of raw water and the frequency of a water taking pump is characterized by comprising the following steps of: S1, monitoring a raw water turbidity value T and a water taking pump running frequency value F in real time; S2, inputting the monitored raw water turbidity value T and the water taking pump frequency value F into a preset control rule set for matching, wherein the control rule set comprises a piecewise fitting formula for calculating a metering pump target frequency value P based on the raw water turbidity value T and the water taking pump frequency value F, and the piecewise fitting formula sets corresponding reference values and coefficients according to different areas of the raw water turbidity value T; S3, outputting a determined metering pump frequency control instruction according to the matching result and the piecewise fitting formula; s4, driving a polyaluminium chloride dosing metering pump to operate according to the metering pump frequency control instruction; the control rule set also defines an accurate mapping relation between the water taking pump frequency value F and the metering pump target frequency value P in different raw water turbidity value T intervals, and the segmentation fitting formula is consistent with the calculation result of the mapping relation.
  2. 2. The method for controlling the addition of polyaluminium chloride based on the turbidity of raw water and the pumping frequency of water as claimed in claim 1, wherein when the turbidity value T of raw water is less than or equal to 6.0NTU, the piecewise fitting formula is that P=28+2×ceil [ (F-32)/3 ], wherein ceil () is an upward rounding function, and the following conditions are satisfied: if F <35.0Hz, ceil [ (F-32)/3 ] =1, p=30.0 Hz; if 35.0Hz is less than or equal to F is less than or equal to 37.0Hz, ceil [ (F-32)/3 ] =1, P=30.0 Hz; if 38.0Hz is less than or equal to F is less than or equal to 40.0Hz, ceil [ (F-32)/3 ] =2, P=32.0 Hz; if 41.0Hz is less than or equal to F is less than or equal to 43.0Hz, ceil [ (F-32)/3 ] =3, P=34.0 Hz; If 44.0Hz is less than or equal to F is less than or equal to 46.0Hz, ceil [ (F-32)/3 ] =4, P=36.0 Hz; if F >46.0Hz, ceil [ (F-32)/3 ] =5, p=38.0 Hz.
  3. 3. The method for controlling the addition of polyaluminum chloride based on the turbidity of raw water and the pump frequency for taking water as set forth in claim 1, wherein when the turbidity value T of raw water is less than or equal to 8.0NTU and is 6.0NTU, the piecewise fitting formula is that P=30+2×ceil [ (F-32)/3 ], wherein ceil () is an upward rounding function, and the following conditions are satisfied: If F <35.0Hz, ceil [ (F-32)/3 ] =0, p=30.0 Hz; if 35.0Hz is less than or equal to F is less than or equal to 37.0Hz, ceil [ (F-32)/3 ] =1, P=32.0 Hz; if 38.0Hz is less than or equal to F is less than or equal to 40.0Hz, ceil [ (F-32)/3 ] =2, P=34.0 Hz; if 41.0Hz is less than or equal to F is less than or equal to 43.0Hz, ceil [ (F-32)/3 ] =3, P=36.0 Hz; If 44.0Hz is less than or equal to F is less than or equal to 46.0Hz, ceil [ (F-32)/3 ] =4, P=38.0 Hz; If F >46.0Hz, ceil [ (F-32)/3 ] =5, p=40.0 Hz.
  4. 4. The method for controlling the addition of polyaluminum chloride based on the turbidity of raw water and the pump frequency for taking water as set forth in claim 1, wherein when the turbidity value T of raw water is 8.0NTU < 12.0NTU, the piecewise fitting formula is P=32+2×ceil [ (F-32)/3 ], wherein ceil () is an upward rounding function, and: If F <35.0Hz, ceil [ (F-32)/3 ] =0, p=32.0 Hz; if 35.0Hz is less than or equal to F is less than or equal to 37.0Hz, ceil [ (F-32)/3 ] =1, P=34.0 Hz; if 38.0Hz is less than or equal to F is less than or equal to 40.0Hz, ceil [ (F-32)/3 ] =2, P=36.0 Hz; if 41.0Hz is less than or equal to F is less than or equal to 43.0Hz, ceil [ (F-32)/3 ] =3, P=38.0 Hz; if 44.0Hz is less than or equal to F is less than or equal to 46.0Hz, ceil [ (F-32)/3 ] =4, P=40.0 Hz; if F >46.0Hz, ceil [ (F-32)/3 ] =5, p=42.0 Hz.
  5. 5. The method for controlling the addition of polyaluminum chloride based on the turbidity of raw water and the pump frequency for taking water as set forth in claim 1, wherein when 12.0NTU < the turbidity value T of raw water is less than or equal to 16.0NTU, the piecewise fitting formula is that P=34+2×ceil [ (F-32)/3 ], wherein ceil () is an upward rounding function, and the following are satisfied: If F <35.0Hz, ceil [ (F-32)/3 ] =0, p=34.0 Hz; if 35.0Hz is less than or equal to F is less than or equal to 37.0Hz, ceil [ (F-32)/3 ] =1, P=36.0 Hz; If 38.0Hz is less than or equal to F is less than or equal to 40.0Hz, ceil [ (F-32)/3 ] =2, P=38.0 Hz; If 41.0Hz is less than or equal to F is less than or equal to 43.0Hz, ceil [ (F-32)/3 ] =3, P=40.0 Hz; If 44.0Hz is less than or equal to F is less than or equal to 46.0Hz, ceil [ (F-32)/3 ] =4, P=42.0 Hz; if F >46.0Hz, ceil [ (F-32)/3 ] =5, p=44.0 Hz.
  6. 6. The method for controlling the addition of the polyaluminum chloride based on the turbidity of the raw water and the pumping frequency of the water as claimed in claim 1, wherein when the turbidity value T of the raw water is more than 16.0NTU, an alarm signal is triggered to prompt a worker to perform manual intervention, the triggering threshold value of the alarm signal meets the condition that T th = 16.0NTU, and when T is more than T th , alarm logic is triggered.
  7. 7. The polyaluminum chloride dosing control method based on raw water turbidity and water taking pump frequency according to claim 1, wherein an alarm signal is triggered, and meanwhile, the current polyaluminum chloride dosing amount is kept or an emergency dosing mode is started, and the metering pump frequency P emerg =P current ×1.1,P current in the emergency dosing mode is the metering pump frequency immediately before an alarm.
  8. 8. The method for controlling the addition of polyaluminium chloride based on the turbidity of raw water and the frequency of a water taking pump according to claim 1 is characterized in that in the step S1, the turbidity value T of raw water is collected in real time through a turbidity sensor of raw water, the collection precision is +/-0.1 NTU, the operation frequency value F of the water taking pump is uploaded through a frequency converter of the water taking pump, the collection precision is +/-0.1 Hz, and the collection frequency is 1 time/second.
  9. 9. The polyaluminium chloride dosing control method based on raw water turbidity and water taking pump frequency as set forth in claim 1, wherein the preset control rule set and a piecewise fitting formula are written into a control unit in a programmable logic controller or a control room in advance, the matching of the step S2, the formula calculation and the control instruction output of the step S3 are executed by the control unit, and the operation delay of the control unit is less than or equal to 100ms.
  10. 10. The polyaluminum chloride dosing control method based on the raw water turbidity and the water taking pump frequency is characterized in that the control unit sends a metering pump frequency control instruction to a frequency converter of a polyaluminum chloride dosing metering pump to drive the polyaluminum chloride dosing metering pump to operate according to a target frequency, the control precision of the metering pump frequency is +/-0.1 Hz, the dosing precision meets Q control =Q rated ×(P/P rated ), wherein Q control is the actual dosing flow, Q rated is the metering pump rated flow, and P rated is the metering pump rated frequency.

Description

Polyaluminum chloride feeding control method based on raw water turbidity and water taking pump frequency Technical Field The invention relates to the technical field of automatic control of water treatment, in particular to a polyaluminium chloride feeding control method based on raw water turbidity and water taking pump frequency. Background In the process of adding coagulant such as polyaluminium chloride in a water works, the traditional mode relies on manual experience, and an operator adjusts the frequency of a metering pump according to the parameters such as raw water turbidity, water quantity and the like by experience, so that obvious defects exist. Firstly, manual adjustment is slow in response, high in hysteresis and difficult to cope with abrupt change of raw water quality, secondly, experience judgment is high in subjectivity, insufficient or excessive addition is easy to cause, the insufficient addition can influence precipitation effect, and excessive addition can increase cost, produce sludge and influence water quality, thirdly, the operation state of a water taking pump cannot be accurately linked, and waste of electric energy and medicament is caused. In the prior art, although partial automatic adding equipment exists, simple proportional control or PID control is adopted, the complex nonlinear relation between the raw water turbidity and the water intake (represented by the water intake pump frequency) is difficult to properly process, and the control precision and stability cannot meet the requirement of high-efficiency water treatment. The core formula of the traditional proportional control is mostly P=k×T+m×F+b (k, m and b are fixed coefficients), and the difference of the influence weights of turbidity and pump frequency on the addition amount in different turbidity intervals is not considered, so that the control deviation is larger. Disclosure of Invention The invention provides a polyaluminium chloride feeding control method based on raw water turbidity and water taking pump frequency, which is characterized in that the frequency of a metering pump is accurately controlled according to a preset control rule set and a piecewise fitting formula by monitoring the raw water turbidity and the water taking pump frequency in real time, so that the refined feeding of the polyaluminium chloride is realized. In order to achieve the above purpose, the present invention adopts the following technical scheme: The polyaluminium chloride feeding control method based on the turbidity of raw water and the water taking pump frequency is suitable for a storage area without main tributaries, and comprises the following specific steps: S1, monitoring a raw water turbidity value T and a water taking pump running frequency value F in real time, specifically, collecting the raw water turbidity value T in real time through a raw water turbidity sensor, wherein the collecting precision is +/-0.1 NTU, uploading the water taking pump running frequency value F through a water taking pump frequency converter, and collecting precision is +/-0.1 Hz, wherein the collecting frequencies are 1 time/second, so that the real-time performance of parameters is ensured. S2, inputting the monitored raw water turbidity value T and the water taking pump frequency value F into a preset control rule set for matching, wherein the control rule set comprises a piecewise fitting formula for calculating the target frequency P of the metering pump based on T and F, the piecewise fitting formula sets corresponding reference values and coefficients according to different areas of T, a control unit in a programmable logic controller or a control room executes matching and formula calculation, and the operation delay of the control unit is less than or equal to 100ms. S3, outputting a determined metering pump frequency control instruction according to the matching result and the calculation result of the segmentation fitting formula. And S4, driving the polyaluminum chloride dosing metering pump to operate according to a metering pump frequency control instruction, and sending the instruction to a metering pump frequency converter by a control unit, wherein the metering pump frequency control precision is +/-0.1 Hz, and the actual dosing flow meets a formula Q control=Qrated×(P/Prated), wherein Q rated is the metering pump rated flow, P rated is the metering pump rated frequency, and the dosing quantity is ensured to be accurate and controllable. The segmentation fitting formula and the mapping relation defined by the control rule set are as follows: 1. When T is less than or equal to 6.0NTU, the piecewise fitting formula is P=28+2×ceil [ (F-32)/3 ] (ceil () is an upward rounding function), and the specific mapping relation is that if F is less than 35.0Hz, P=30.0 Hz, if F is less than or equal to 35.0Hz and less than or equal to 37.0Hz, P=30.0 Hz, if F is less than or equal to 38.0Hz and less than or equal to 40.0Hz, P=32.0 Hz, if