CN115231762B - Control method based on magnetic coagulation water treatment system - Google Patents
Control method based on magnetic coagulation water treatment system Download PDFInfo
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- 238000005345 coagulation Methods 0.000 title claims abstract description 133
- 230000015271 coagulation Effects 0.000 title claims abstract description 133
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 113
- 238000000034 method Methods 0.000 title claims abstract description 101
- 238000003756 stirring Methods 0.000 claims abstract description 177
- 239000007787 solid Substances 0.000 claims abstract description 136
- 238000002156 mixing Methods 0.000 claims abstract description 125
- 239000010865 sewage Substances 0.000 claims abstract description 46
- 238000010992 reflux Methods 0.000 claims abstract description 29
- 238000013461 design Methods 0.000 claims abstract description 13
- 238000004062 sedimentation Methods 0.000 claims description 36
- 239000010802 sludge Substances 0.000 claims description 25
- 238000005259 measurement Methods 0.000 claims description 20
- 238000004891 communication Methods 0.000 claims description 11
- 238000001556 precipitation Methods 0.000 claims description 10
- 230000003311 flocculating effect Effects 0.000 claims description 7
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- 239000002351 wastewater Substances 0.000 claims description 4
- 230000003750 conditioning effect Effects 0.000 claims description 3
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Classifications
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/48—Treatment of water, waste water, or sewage with magnetic or electric fields
- C02F1/488—Treatment of water, waste water, or sewage with magnetic or electric fields for separation of magnetic materials, e.g. magnetic flocculation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
- B01F27/80—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis
- B01F27/85—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis with two or more stirrers on separate shafts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
- B01F27/80—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis
- B01F27/90—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis with paddles or arms
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/20—Measuring; Control or regulation
- B01F35/22—Control or regulation
- B01F35/221—Control or regulation of operational parameters, e.g. level of material in the mixer, temperature or pressure
- B01F35/2211—Amount of delivered fluid during a period
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/20—Measuring; Control or regulation
- B01F35/22—Control or regulation
- B01F35/221—Control or regulation of operational parameters, e.g. level of material in the mixer, temperature or pressure
- B01F35/2214—Speed during the operation
- B01F35/22142—Speed of the mixing device during the operation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F2101/00—Mixing characterised by the nature of the mixed materials or by the application field
- B01F2101/305—Treatment of water, waste water or sewage
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F2001/007—Processes including a sedimentation step
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Analytical Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Mixers Of The Rotary Stirring Type (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
Abstract
The invention relates to a control method based on a magnetic coagulation water treatment system, which comprises the following steps: step 2, calculating the optimal stirring strength G of the mixing and stirring pool 0 Calculating the optimal rotation speed of the stirrer according to the optimal stirring intensity; step 3, at the optimal stirring intensity G 0 The optimal solid content range [ a, b ] of the computing system]The method comprises the steps of carrying out a first treatment on the surface of the Step 4, controlling the stirrer to run at the optimal rotation speed, and monitoring the solid content H of the system in the mixing and stirring tank; and regulating the system solid content in the mixing and stirring tank by changing the reflux quantity of the magnetic mud, so that the system solid content H is in the optimal solid content range. The method closely associates the design of the magnetic coagulation water treatment system with the control process in actual operation, so that the designed magnetic coagulation water treatment system can operate in a mode which is most beneficial to improving the sewage treatment effect under various water quality conditions, and is very convenient for accurately controlling the actual operation process, thereby ensuring that the effluent reaches the standard.
Description
Technical Field
The invention relates to the technical field of magnetic coagulation water treatment, in particular to a control method based on a magnetic coagulation water treatment system.
Background
The magnetic coagulation water treatment process is used as a deep water purification technology, has the characteristics of simple process, small equipment occupation, large treatment capacity, strong impact load resistance, low operation cost, long service life of equipment, stable water outlet of grade 1A or higher standard and the like, is increasingly and widely focused in the industry, and is increasingly applied to the fields of scale improvement and transformation of sewage treatment plants, deep dephosphorization of wastewater, heavy metal wastewater treatment, black and odorous river treatment and the like.
The existing magnetic coagulation water treatment process is generally implemented in a magnetic coagulation water treatment system, and the magnetic coagulation water treatment generally comprises three links of magnetic medium coagulation stirring, magnetic medium precipitation and magnetic medium recovery, wherein the magnetic medium coagulation stirring link refers to a process of gathering colloid particles and tiny suspended matters in sewage by adding a medicament and magnetic medium (or called magnetic particles) so as to form stronger flocs (or called flocs) with higher density for subsequent rapid sedimentation; it can be decomposed into two stages, coagulation and flocculation. The magnetic medium sedimentation link is to separate suspended matters such as flocs, sludge and the like in the sewage by utilizing a gravity sedimentation mode, so that the solid-liquid rapid separation is realized, the sewage is purified, and the purpose of purifying the sewage is achieved. In the separated magnetic mud, a part of the magnetic mud can flow back to the magnetic medium coagulation stirring link to realize sludge backflow, and the residual sludge can enter the magnetic medium recovery link, so that the magnetic medium recovery link is mainly used for recovering the magnetic medium in the magnetic mud, the magnetic medium can be recycled, and the economical efficiency is improved.
The magnetic coagulation water treatment process is the biggest difference from the traditional coagulation sedimentation process: the magnetic coagulation water treatment process is a magnetic precipitation water treatment process, magnetic particles (namely magnetic media) are required to be continuously added into sewage in the operation process, and the traditional coagulation precipitation process does not need to add the magnetic media into the sewage. However, on one hand, the design and operation of equipment (especially equipment in a magnetic medium coagulation stirring link) in the existing magnetic coagulation water treatment system still remain the theoretical system of traditional coagulation sedimentation, but the key factor that a magnetic medium with large specific gravity is introduced in the process of adding magnetic sedimentation water treatment so that the formed flocculation density is larger is omitted. On the other hand, in the magnetic coagulation water treatment system, the magnetic medium coagulation stirring link is the core of the whole system, and in order to control the sewage treatment effect, the prior art generally adopts a G value and a GT value as coagulation control indexes, wherein G represents the velocity gradient of the movement of two particles in two adjacent water layers, which means the velocity difference in the distance between the vertical water flows due to stirring (also referred to as "stirringIntensity of mixing "), reflecting the particle collision frequency; the GT value corresponds to the total number of collisions of particles per volume of water. Because the G value is obtained when the water flow is in a laminar flow state, in practice, in a flocculation stage, the water flow is not in a laminar flow state, and is always in a turbulent flow state, vortex with different sizes exist in the fluid, and besides the advancing speed, longitudinal and transverse pulsation speeds exist, namely, the G value can only represent the space average dissipation rate of energy and cannot reflect the dissipation rate of each local energy; the GT value is too large (10 4 ～10 5 ) Often can meet the requirement, and loses the practical control significance; moreover, the G value and the GT value can be measured only in a laboratory, and cannot be measured on line in the sewage treatment process, so that the actual operation process of the magnetic coagulation water treatment system is difficult to control through the G value and the GT value. Based on the two reasons, the existing magnetic coagulation water treatment system is disconnected from the control in the actual operation process, so that the designed magnetic coagulation water treatment system is difficult to operate in a mode which is most favorable for improving the sewage treatment effect under various water quality conditions, and the problem that accurate control is inconvenient, the water outlet effect cannot keep stable and high-quality water outlet along with the fluctuation of water quality in the actual operation process is caused due to lack of proper control indexes, so that the problem is to be solved.
Disclosure of Invention
The first aspect of the present invention is to solve the problems that the existing magnetic coagulation water treatment system is difficult to operate in a mode which is most favorable for improving sewage treatment effect under various water quality conditions and is inconvenient to accurately control the actual operation process due to the fact that the existing magnetic coagulation water treatment system is disjointed from the control in the actual operation process, and the main concept is that:
The control method based on the magnetic coagulation water treatment system is applied to the magnetic coagulation water treatment system, and the magnetic coagulation water treatment system comprises a coagulation device for conditioning sewage and a precipitation device for separating magnetic mud, wherein the coagulation device is provided with a mixing and stirring tank, and a stirrer is arranged in the mixing and stirring tank; the mixing and stirring tank is communicated with the sedimentation device, and a mud discharge port of the sedimentation device is communicated with the mixing and stirring tank and is used for refluxing magnetic mud; the method comprises the following steps:
2. calculating the optimal stirring strength G of the mixing and stirring pool 0 Calculating the optimal rotation speed of the stirrer according to the optimal stirring intensity;
3. at the optimum stirring strength G 0 The optimal solid content range [ a, b ] of the computing system]；
4. Controlling the stirrer to run at the optimal rotating speed, and monitoring the solid content H of the system in the mixing and stirring tank; and regulating the system solid content in the mixing and stirring tank by changing the reflux quantity of the magnetic mud, so that the system solid content H is in the optimal solid content range. In the method, the stirring intensity is used as a coagulation stirring control index and not used as a coagulation effect control index, so that the limitation existing when the G value and the GT value are used as the coagulation effect control index in the design and operation of the conventional mixing stirring pool is solved; in the operation process of the mixing and stirring tank, the larger the stirring intensity is, the better the coagulation effect is, therefore, in the step 2, the optimal stirring intensity of the mixing and stirring tank is calculated based on the actual mixing and stirring tank, the essence is to find the optimal stirring intensity corresponding to the optimal coagulation effect of the mixing and stirring tank, and the optimal rotating speed of the stirrer can be calculated according to the optimal stirring intensity, so that in the actual operation process, the optimal coagulation effect can be obtained in the mixing and stirring tank only by controlling the rotating speed of the stirrer to be the optimal rotating speed. Because the treatment effect of the whole system can have larger fluctuation and difference under different water quality conditions, in the method, the solid content of the system is creatively used as a coagulation effect control index and the stirring strength G is optimal 0 The optimal solid content range [ a, b ] of the computing system]The method can effectively represent the coagulation effect of the whole system and is convenient to control the coagulation effect of the system by utilizing the optimal solid content range, so that in the actual operation process, the stirrer can be operated at the optimal rotation speed, and the solid content H of the system in the mixing and stirring tank can be synchronously monitored;when the system solids content exceeds the optimal solids content range [ a, b]When the magnetic mud reflux quantity is changed, the system solid content in the mixing and stirring tank can be regulated, so that the system solid content H is in the optimal solid content range, the accurate control of the magnetic coagulation water treatment process is convenient to realize, the designed magnetic coagulation water treatment system can be ensured to operate in a mode which is most beneficial to improving the sewage treatment effect under various water quality conditions, and the water quality of effluent can be obviously improved.
In order to solve the problems associated with the design and operation of the system, the method further comprises the step 1 of determining pool shape parameters of a mixing and stirring pool in the coagulation device, and determining size and structure parameters of the stirrer according to the pool shape parameters and design specifications, wherein the size and structure parameters at least comprise the diameters of blades, the number of the blades and the width of the blades. In the scheme, pool shape parameters of the mixing stirring pool are determined firstly, and size structure parameters of the stirrer are determined through the pool shape parameters, so that the stirrer is more suitable for the mixing stirring pool, and the optimal stirring strength can be obtained by changing the rotating speed of the stirrer under the condition that the pool shape parameters and the size structure parameters are the best match, so that the design of the system and the operation effect are precisely associated.
The second aspect of the present invention is to solve the problem of calculating the optimal stirring strength of the mixing and stirring tank in the magnetic coagulation water treatment system, further, in the step 2, a G-df fitting curve is calculated first, and the optimal stirring strength G is obtained through the G-df fitting curve 0 Wherein df represents the two-dimensional fractal dimension of the floccules in the wastewater. Under the condition that the stirring intensity is used as a coagulation stirring control index and not used as a coagulation effect control index, the method further introduces the concept of fractal dimension containing information such as the size, the density and the like of the floccules by analyzing a coagulation morphology theory, and the change of the fractal dimension is used as the coagulation effect control index, so that the forming process and the rule of the floccules under certain stirring conditions can be reflected more accurately, and the method is more beneficial to accurately calculating the optimal stirring intensity of each mixing stirring pool; meanwhile, the method utilizes the G-df fitting curve to obtain the optimal stirring strength, can avoid the interference of other factors, and is very convenient, accurate and efficient。
In order to solve the problem of facilitating the obtaining of the optimal stirring strength, it is preferable to calculate the optimal stirring strength G in the step 2 0 The method of (1) is as follows:
2.1, taking the rotating speed of the stirrer as a variable, observing the two-dimensional fractal dimension df of floccules in sewage under different G values by changing the rotating speed of the stirrer, and obtaining at least three groups of measurement data taking the G value as an abscissa and taking the df as an ordinate;
2.2, marking each group of measurement data in a plane rectangular coordinate system, and obtaining a G-df fitting curve through data fitting;
2.3 obtaining the optimal stirring intensity G according to the G-df fitting curve 0 。
In order to solve the problem of calculating the optimal rotation speed of the stirrer, in step 2, according to the optimal stirring strength G 0 The formula for calculating the optimum rotational speed of the stirrer is:
wherein: q (Q) t Mixing and stirring tank flow (m 3 /s)；
Mu-viscosity of water (pa·s), in practical use, mu=1.14X10 can be taken -3 Pa·s；
K g The operating mode coefficient of the motor in the stirrer can be 1.2 when the motor continuously operates for 24 hours every day;
the total efficiency of eta-mechanical transmission can be 0.92 when in practical application;
c-drag coefficient, c=0.2 to 0.5, and in practical application, c=0.5 may be taken;
the density of the ρ -mixture may be 1150kg/m in practical use 3 ；
Omega-stirrer rotational speed, omega = 2× (pi n/60), rad/s, n is stirrer rotational speed;
z-number of paddles;
the number of layers of the e-stirrer, C=H/D, and C > 1.3, and in actual application, e=2 can be adopted; c is less than or equal to 1.3, e=1, d is the equivalent diameter of the cross section of the tank body, and H is the height of the tank;
b-the width of the stirring blade, b= (0.1-0.25) d (m), d being the diameter of the stirrer;
r-stirring blade radius, R= (1/6-1/3) D (m);
The installation angle of the theta-stirring blade can be 45 degrees in practical application;
g-gravity acceleration of 9.8m/s can be generally taken 2 。
In order to solve the problem of being convenient for measuring the two-dimensional fractal dimension of the flocculating constituent in the sewage, the method for measuring the two-dimensional fractal dimension df of the flocculating constituent in the sewage is further as follows: firstly, taking a proper amount of coagulated suspension from a mixing and stirring tank and placing the suspension on a glass slide;
measuring L and A of at least two floccules under a microscope to obtain at least two groups of data points taking lnL as an abscissa and lnA as an ordinate, wherein A is a projection surface of the floccules, and L is the maximum perimeter of projection;
and finally, carrying out straight line fitting on each group of data points, wherein the slope of the fitted straight line is the two-dimensional fractal dimension df.
The third aspect of the present invention is to solve the problem of calculating an optimal solid content range of a magnetic coagulation water treatment system, further, in the step 3, an H-df fitting curve is calculated first, and the optimal solid content range [ a, b ] is obtained through the H-df fitting curve, wherein H represents the solid content of the system. In the method, the optimal solid content range [ a, b ] of the system is calculated through the H-df fitting curve, and the system solid content H and the two-dimensional fractal dimension df can be correlated together, so that the relationship between the solid content and the coagulation effect can be intuitively and accurately reflected by utilizing the two-dimensional fractal dimension df, and the optimal solid content range can be more conveniently obtained. The method can be matched with the optimal stirring intensity to obtain the optimal solid content range of the system under the condition of the optimal stirring intensity, so that the whole system can operate in a mode which is most favorable for improving the sewage treatment effect under various water quality conditions, and the water quality of the effluent can be obviously improved.
In order to solve the problem of facilitating the calculation of the optimal solid content range, preferably, the method of calculating the optimal solid content range [ a, b ] in step 3 is as follows:
3.1, maintaining the stirring strength of the mixing stirring tank to be G 0 Taking the system solid content H in the mixing and stirring tank as a variable, examining the two-dimensional fractal dimension df of the floccules in the sewage under the condition of the same stirring strength by changing the system solid content H in the mixing and stirring tank, and obtaining at least three groups of measurement data taking H as an abscissa and df as an ordinate;
marking each group of measurement data in a plane rectangular coordinate system, and obtaining an H-df fitting curve through data fitting;
3.3, obtaining the optimal solid content range [ a, b ] of the system according to the H-df fitting curve.
Preferably, in step 3.3, the method for calculating the optimal lower solid content limit a is: setting a two-dimensional fractal dimension lower limit df0, and calculating corresponding system solid content H by utilizing an H-df fitting curve or a fitting formula corresponding to the H-df fitting curve 0 Let a=h 0 ；
And/or, the method for calculating the optimal solid content upper limit b is as follows: setting an upper limit df1 of a two-dimensional fractal dimension, and calculating corresponding system solid content H by utilizing an H-df fitting curve or a fitting formula corresponding to the H-df fitting curve 1 Let b=h 1 。
Preferably, the lower fractal dimension limit df0 = 2; and/or, the fractal dimension upper limit df1 = 3.
In order to solve the problem of being convenient for measuring a plurality of groups of measurement data, in step 3.1, the solid content H of the system in the mixing and stirring tank is changed by changing the reflux quantity of the magnetic mud. The system solid content H in the mixing and stirring pool is changed in the mode, so that the operation is simple and convenient, and one group of measurement data can be measured under the working condition of each system solid content H, so that multiple groups of measurement data can be conveniently obtained, and the H-df fitting curve can be calculated.
The fourth aspect of the present invention is to solve the problem of accurately controlling the magnetic mud reflux amount on line during the operation of the magnetic coagulation water treatment system, further, the magnetic coagulation water treatment system is further configured with a controller, a sensor and a flow control device, the controller is electrically connected with the sensor, the stirrer and the flow control device respectively, and the flow control device is arranged on a communication path between the mud discharge port and the coagulation device;
in the step 4, a controller is used for controlling the stirrer to operate at the optimal rotating speed, and a sensor is used for monitoring the system solid content H in the mixing and stirring tank; when the system solid content H is larger than the upper limit b of the optimal solid content, the controller reduces the reflux quantity of the magnetic mud by controlling the flow control device, so that the system solid content in the mixing and stirring tank is reduced, and the system solid content H is in the optimal solid content range; when the system solid content H is smaller than the lower limit a of the optimal solid content, the controller increases the magnetic mud reflux quantity by controlling the flow control device, so that the system solid content in the mixing and stirring tank is increased, and the system solid content H is in the optimal solid content range. The system can operate in the optimal solid content range under any water quality condition by detecting and controlling the solid content of the system, so that the effluent quality can be ensured to reach the standard.
Preferably, the flow control device is a control valve. The controller valve comprises a two-way control valve, a three-way control valve and the like.
Preferably, the controller is a PC, a singlechip or a PLC.
Preferably, the sensor is an on-line suspended matter monitor.
Compared with the prior art, the control method based on the magnetic coagulation water treatment system provided by the invention has the advantages that the stirring intensity is used as the coagulation stirring control index and not used as the coagulation effect control index, the system solid content is used as the coagulation effect control index, and the optimal solid content range of the system is matched, so that the design of the magnetic coagulation water treatment system is closely related to the control process in actual operation, the designed magnetic coagulation water treatment system can operate in a mode which is most beneficial to improving the sewage treatment effect under various water quality conditions, and the actual operation process is very convenient to precisely control, so that the effluent reaches the standard.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a block diagram of a control method based on a magnetic coagulation water treatment system according to an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a first magnetic coagulation water treatment system according to an embodiment of the present invention.
FIG. 3 is a schematic diagram of a second magnetic coagulation water treatment system according to an embodiment of the present invention.
Fig. 4 is a schematic structural diagram of a third magnetic coagulation water treatment system according to an embodiment of the present invention.
FIG. 5 is a graph of a G-df fit obtained using the control method provided by the present invention.
FIG. 6 is another graph of G-df fits obtained using the control method provided by the present invention.
FIG. 7 is a graph of an H-df fit obtained using the control method provided by the present invention.
Description of the drawings
PAC preparation device 101, PAC metering pump 102, PAM preparation device 103, and PAM metering pump 104
Coagulation device 200, first mixing tank 201, second mixing tank 202, third mixing tank 203, sensor 204, stirrer 205, baffle 206, and guide cylinder 207
Sedimentation device 300, sedimentation chamber 301, inclined tube 302, reflux pump 303, flow control device 304, magnetic mud pump 305, residual sludge pump 306, pipeline 307, and stirring mechanism 308
Magnetic recovery device 400.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by a person skilled in the art without making any inventive effort, are intended to be within the scope of the present invention.
Example 1
In the embodiment, a control method based on a magnetic coagulation water treatment system is provided, wherein,
as shown in fig. 2, the magnetic coagulation water treatment system includes a PAC preparation apparatus 101, a PAM preparation apparatus 103, a coagulation apparatus 200 for conditioning sewage, a precipitation apparatus 300 for separating magnetic mud, a magnetic recovery apparatus 400, and a controller, wherein,
As shown in fig. 2, the coagulation device 200 is constructed with a mixing tank to provide a space for a coagulation process and a flocculation process of sewage, and a stirrer 205 is provided in the mixing tank to enhance stirring strength. In practice, the number of mixing tanks constructed in the coagulation device 200 may be determined according to actual needs, and preferably, at least two mixing tanks communicating with each other may be constructed in the coagulation device 200. For example, as shown in fig. 2, three mixing tanks communicating with each other are constructed in the coagulation device 200, and the coagulation device 200 is further provided with a water inlet and a water outlet, which communicate with the mixing tanks at the ends, respectively. For convenience of description, the three mixing and stirring tanks are a first mixing and stirring tank 201, a second mixing and stirring tank 202 and a third mixing and stirring tank 203, the first mixing and stirring tank 201, the second mixing and stirring tank 202 and the third mixing and stirring tank 203 are sequentially communicated with each other, as shown in fig. 2, a water inlet is communicated with the first mixing and stirring tank 201, a water outlet is communicated with the third mixing and stirring tank 203, and a stirrer 205 can be arranged in the first mixing and stirring tank 201, and the stirrer 205 is mainly used for enhancing the stirring strength in the first mixing and stirring tank 201, as shown in fig. 4; a plurality of static baffles 206 may also be provided, as shown in fig. 2 or 3, the static baffles 206 are mainly used to make the flow path of the sewage more tortuous, so that the coagulant and the sewage can be fully mixed in the first mixing tank 201. The second mixing tank 202 is provided with a stirrer 205, and the added magnetic medium and the reflowed magnetic slurry are generally added to the second mixing tank 202, as shown in fig. 2-4. The third mixing tank 203 is provided with a stirrer 205 so that sewage can be fully mixed and reacted with the coagulant aid added.
In this embodiment, PAC manufacturing apparatus 101 is in communication with the water inlet, as shown in fig. 2, PAC manufacturing apparatus 101 is mainly used for manufacturing a pharmaceutical agent, such as a coagulant. In practice, PAC manufacturing apparatus 101 is further provided with PAC metering pump 102 in the communication path with the water inlet, so that PAC metering pump 102 is used to precisely control the output of the medicament. As shown in fig. 2, the PAM preparation device 103 may be connected to the third mixing tank 203 through a pipe 307, so as to add the prepared coagulant aid into the third mixing tank 203, and in the same way, in implementation, a PAM metering pump 104 is further disposed on a communication path between the PAM preparation device 103 and the third mixing tank 203, so that the output of the medicament is accurately controlled by using the PAM metering pump 104.
In this embodiment, the sedimentation device 300 may adopt an existing sedimentation tank, and the sedimentation device 300 may utilize a sedimentation manner to separate the magnetic mud from the water body in the sewage. For example, as shown in fig. 2, the sedimentation device 300 is configured with a sedimentation chamber 301, a sludge discharge port, and a water outlet, wherein the sludge discharge port and the water outlet are respectively communicated with the sedimentation chamber 301, the water outlet of the coagulation device 200 is communicated with the sedimentation chamber 301 of the sedimentation device 300, and an inclined tube 302 (or an inclined plate) for enhancing sedimentation and a stirring mechanism 308 (including a motor, a transmission shaft connected with the motor in a transmission manner, a hanger mounted on the transmission shaft, etc.) are generally disposed in the sedimentation chamber 301, as shown in fig. 2, and will not be repeated herein. In the actual operation process, sewage is precipitated in the precipitation cavity 301 of the precipitation device 300, the precipitated magnetic mud is discharged out of the precipitation device 300 through the mud discharge port, and clear water after separating the magnetic mud is discharged through the water outlet.
In this embodiment, the magnetic recovery device 400 is mainly used for recovering magnetic media in magnetic mud, and an existing magnetic disk type magnetic separator or drum type magnetic separator can be adopted, so that separation of the magnetic media in the magnetic mud from the mud can be realized by using the principle of magnetic adsorption. When assembled, the magnetic recovery device 400 is communicated with the mud discharging port of the sedimentation device 300 so as to receive and separate the magnetic medium in the magnetic mud; the magnetic recovery device 400 is also in communication with the coagulation device 200, for example, as shown in fig. 2, the magnetic recovery device 400 is in communication with the second mixing tank 202 of the coagulation device 200 so as to input at least a portion of the recovered magnetic medium into the second mixing tank 202 to effect recycling of the magnetic medium.
In this embodiment, the coagulation device 200 is also in communication with the sludge discharge port of the sedimentation device 300 so as to reflux the magnetic sludge, as shown in fig. 2. Since the magnetic recovery device 400 and the coagulation device 200 are respectively connected to the sludge discharge port of the precipitation device 300, during operation, the requirement of the magnetic sludge for backflow is satisfied first, and the residual sludge (simply referred to as residual sludge) enters the magnetic recovery device 400. For diverting the magnetic mud, there are various embodiments, and as an example, in this embodiment, a reflux pump 303 and a flow control device 304 for controlling the reflux amount are disposed on a communication path between the mud discharging port of the settling device 300 and the coagulation device 200. In practice, the flow control device 304 may employ a control valve, which may be a two-way control valve, a three-way control valve, etc. commonly used in the art, and in this embodiment, the flow control device 304 employs a solenoid valve, for example. Of course, in a more sophisticated scheme, to monitor the reflux amount of the magnetic mud, a flowmeter may be further configured on the communication path between the mud discharging port of the settling device 300 and the coagulation device 200. Meanwhile, a surplus sludge pump 306 is disposed on a communication path of the magnetic recovery device 400 and the settling device 300 so that surplus magnetic sludge is inputted into the magnetic recovery device 400 by the surplus sludge pump 306, as shown in fig. 2. In practice, the sludge discharge port and the coagulation device 200 may be connected via a pipe 307 or a channel, and similarly, the sludge discharge port and the magnetic recovery device 400 may be connected via a pipe 307 or a channel.
In the actual operation process, sewage enters the first mixing and stirring tank 201 of the coagulation device 200 through the water inlet, and is fully mixed with coagulant in the first mixing and stirring tank 201; then the sewage enters a second mixing and stirring tank 202, and under the action of a stirrer 205, the magnetic medium, the reflux magnetic mud and the sewage are fully mixed in the second mixing and stirring tank 202; then sewage enters the third mixing and stirring tank 203, is fully mixed with coagulant in the third mixing and stirring tank 203, enters the sedimentation device 300 through a water outlet, is sedimentated in the sedimentation device 300, separated clean water is discharged through a water outlet of the sedimentation device 300, precipitated magnetic mud is conveyed backwards through a mud discharge outlet of the sedimentation device 300, part of the magnetic mud can be refluxed to the coagulation device 200 as required, residual sludge is input into the magnetic recovery device 400 for recovery of the magnetic medium, and the recovered magnetic medium can be conveyed to the coagulation device 200 for recycling of the magnetic medium.
In order to closely correlate the design of the magnetic coagulation water treatment system with the control in the actual operation process, as shown in fig. 1, the control method provided by the embodiment comprises the following steps:
Step 1, in the design stage of the coagulation device 200 in the magnetic coagulation water treatment system, it is necessary to determine pool shape parameters of the mixing pool in the coagulation device 200, wherein the pool shape parameters include the shape and the size of the mixing pool, and then the size structure parameters of the stirrer 205 can be determined according to the pool shape parameters and related design specifications (such as GB), the purpose of the stirrer 205 is to increase stirring intensity, and the stirrer 205 can be an existing stirrer 205, for example, the stirrer 205 can include a motor, a transmission shaft connected with the motor, and a plurality of paddles mounted on the transmission shaft. In implementation, the dimensional structural parameters at least include the blade diameter, the blade number and the blade width, and of course, the number of layers of the stirrer 205, the installation angle of the stirring blades, and the like. So as to find the most suitable stirrer 205 which is most favorable for improving the stirring strength according to the mixed stirring pool with the pool-shaped parameters determined, so as to realize better coagulation effect. In practice, for a coagulation device 200 constructed with a plurality of mixing tanks, each of which may be designed in the manner described above to obtain an optimal stirring effect in each mixing tank, as shown in fig. 2-4.
Step 2, calculating the optimal stirring strength G of the mixing and stirring pool 0 And calculates the optimal rotational speed of the stirrer 205 based on the optimal stirring intensity, wherein the optimal rotational speed may be the angular speed of the stirrer 205 or the linear speed of the stirrer 205. After the design and manufacture of the mixing tank and the stirrer 205 are finished, in the actual operation process, the larger the rotation speed of the stirrer 205 is, the larger the stirring strength G in the mixing tank is, but in the magnetic coagulation water treatment process, the process with the best coagulation effect should meet two basic requirements: firstly, tiny particles in water form flocs which are easy to remove in a sedimentation cavity 301 in a mixing and stirring pool; on the other hand, the coagulation is completed with minimum duration, coagulant dosage and energy dissipation, so that the maximum economic benefit is obtained. It was therefore found that: the greater the stirring intensity G does not represent the best coagulation effect achieved in the mixing tank. In view of this, in combination with the limitations of the prior art that the G value and the GT value are used as the control indexes of the coagulation effect (where G represents the velocity gradient of the movement of two particles in two adjacent water layers, and means that the collision frequency of the particles is reflected due to the velocity difference (also referred to as "stirring intensity") of stirring at the distance of vertical water flow, and the GT value corresponds to the total number of collisions of particles in the volume of water), the method uses only the stirring intensity G as the control index of the coagulation stirring effect instead of the control index of the coagulation effect, so as to solve the limitations of the existing design and operation of the mixing stirring tank that the G value and the GT value are used as the control indexes of the coagulation effect. Meanwhile, in the method, the concept of fractal dimension containing information such as the size, the density and the like of the floccules is introduced by analyzing the coagulation morphology theory and used as a coagulation effect control index, and the change of the fractal dimension can more accurately reflect the formation process and the rule of the floccules under a certain stirring condition. In the method, the fractal dimension of the flocculating constituent is calculated according to the functional relation between the projection area and the maximum perimeter of the flocculating constituent, and the functional relation between the projection area and the maximum length of the flocculating constituent is as follows:
A＝αL df
Wherein: a-is the projection surface of the flocculating constituent;
l-is the maximum circumference of the projection;
alpha-is a proportionality constant;
df-is the two-dimensional fractal dimension of the floccule.
And obtaining natural logarithms of the above steps to obtain:
lnA＝lnα+dflnL
as can be seen from the above formula, lnL and lnA are in a linear relationship, and therefore, in this embodiment, the method for measuring the two-dimensional fractal dimension of the floccules in the sewage is: firstly, taking out a proper amount of suspension after coagulation in a mixing and stirring tank by using a large-belly pipette, and placing the suspension on a glass slide; observing under a microscope, performing image processing on an electronic computer connected with an electronic microscope camera lens and a video image capturer, measuring L and A of different floccules (at least two), and respectively calculating lnL and lnA, so as to obtain at least two groups of data points taking lnL as an abscissa and lnA as an ordinate; and finally, data processing software (such as Excel, SPSS, MATLAB and the like) can be utilized to carry out linear fitting on each group of data points, and the slope of the fitted straight line is the two-dimensional fractal dimension df of the floccules in the sewage. In actual operation, in order to improve accuracy, the method can measure at least twice so as to obtain at least two-dimensional fractal dimensions, and finally, the average value of each two-dimensional fractal dimension is calculated as the final two-dimensional fractal dimension df, so that the accuracy can be remarkably improved, and the error can be reduced.
To calculate the optimal stirring strength G of the mixing and stirring pool in the magnetic coagulation water treatment system 0 In a preferred embodiment, in the step 2, a G-df fitting curve may be calculated first, and as shown in FIGS. 5 and 6, the optimal stirring intensity G may be calculated from the G-df fitting curve 0 Wherein df represents the two-dimensional fractal dimension of the floccules in the wastewater. For example, the optimum stirring strength G is calculated in step 2 0 The method of (2) may comprise:
2.1, taking the rotating speed of the stirrer 205 as a variable, examining the two-dimensional fractal dimension df of the floccules in the sewage under different G values by changing the rotating speed of the stirrer 205, and obtaining at least three groups of measurement data taking the G value as an abscissa and taking the df as an ordinate. Specifically, when the magnetic coagulation water treatment system is operated, different stirring intensities G can be obtained by changing the rotation speed of the stirrer 205, after each stirring intensity G is stabilized, the two-dimensional fractal dimension df corresponding to the stirring intensity G can be measured by the above-described method for measuring the two-dimensional fractal dimension, so that a set of measurement data can be obtained, and the above-described process can be repeated usually 5 to 8 times to obtain 5 to 8 sets of measurement data, as shown in fig. 5 and 6.
And 2.2, marking each group of measurement data in a plane rectangular coordinate system, and obtaining a G-df fitting curve through data fitting. In this step, the data fitting process may be calculated by using existing data processing software, or may be manually calculated by using an existing mathematical formula, which is not described herein, for example, as shown in fig. 5, a G-df fitting curve is obtained under the condition that only the stirrer 205 is disposed in the first mixing tank 201 and the guide cylinder 207 is not disposed; as shown in fig. 6, a G-df fitted curve is obtained when a stirrer 205 is provided in the first mixing tank 201 and a guide tube 207 is provided.
2.3 obtaining the optimal stirring intensity G according to the G-df fitting curve 0 . In practice, a G-df fitting curve can be drawn, as shown in FIG. 5 or FIG. 6, the highest point is found from the graph, and the abscissa corresponding to the highest point is the optimal stirring strength G 0 Of course, the formula of the G-df fitting curve can be utilized to directly calculate the abscissa corresponding to the maximum value, thus obtaining the optimal stirring strength G 0 . As shown in FIGS. 5 and 6, the optimal stirring intensity G of the magnetic coagulation water treatment system can be obtained 0 270s -1 。
When the stirring strength G is optimal 0 After the determination, the optimum stirring strength G can be utilized 0 The optimum rotational speed of the stirrer 205 is calculated, specifically, according to the optimum stirring intensity G 0 The formula for calculating the optimum rotational speed of the agitator 205 is:
wherein: q (Q) t Mixing and stirring tank flow (m 3 /s)；
Mu-viscosity of water (pa·s), in practical use, mu=1.14X10 can be taken -3 Pa·s；
K g The operating factor of the motor in the stirrer 205, which can be 1.2, is set for 24 hours of continuous operation per day;
the total efficiency of eta-mechanical transmission can be 0.92 when in practical application;
c-drag coefficient, c=0.2 to 0.5, and in practical application, c=0.5 may be taken;
the density of the ρ -mixture may be 1150kg/m in practical use 3 ；
Omega-stirrer 205 angular velocity, omega = 2× (n/60), rad/s, n is stirrer rotational speed;
z-number of paddles;
the number of layers of the e-stirrer 205, C=H/D, and C > 1.3, and in practical application, e=2 can be adopted; c is less than or equal to 1.3, e=1, d is the equivalent diameter of the cross section of the tank body, and H is the height of the tank;
b-width of stirring blade, b= (0.1-0.25) d (m), d is diameter of stirrer 205;
r-stirring blade radius, R= (1/6-1/3) D (m);
the installation angle of the theta-stirring blade can be 45 degrees in practical application;
g-gravity acceleration of 9.8m/s can be generally taken 2 。
It will be appreciated that when the coagulation device 200 includes a plurality of mixing tanks provided with the stirrer 205, the optimal stirring strength G of each mixing tank can be calculated by using the step 2 0 And the optimal rotational speed of each agitator 205, such that each agitator 205 operates at its own optimal rotational speed during actual operation.
Step 3, at the optimal stirring intensity G 0 The optimal solid content range [ a, b ] of the computing system]To be in the optimum solid content range [ a, b ]]For reference, the actual solid content of the system is controlled, so that the aim of effectively controlling the whole process is fulfilled. For convenience ofCalculating the optimal solids content range for a magnetic coagulation water treatment system, in a preferred embodiment, an H-df fitting curve may be calculated first, as shown in FIG. 7, and then the H-df fitting curve is used to obtain the optimal solids content range [ a, b ] ]Where H represents the system solids (which may also be referred to as suspended matter concentration, meaning the concentration of suspended matter in the body of water, including suspended sludge, magnetic media, and flocs, etc.). Specifically, in step 3, the optimal solid content range [ a, b ] is calculated]The method of (1) comprises:
3.1, the stirring strength of the mixing tank is kept at G by controlling the rotation speed of the stirrer 205 0 I.e. such that the mixing tank has a stirring intensity G that is always at optimum 0 Status of the device. Meanwhile, the system solid content H in the mixing and stirring tank is used as a variable, the two-dimensional fractal dimension df of the floccules in the sewage under the condition of the same stirring strength is inspected by changing the system solid content H in the mixing and stirring tank, and at least three groups of measurement data taking H as an abscissa and df as an ordinate can be obtained. Specifically, the rotational speed of the stirrer 205 is maintained so that the stirring strength of the mixing tank is maintained at G 0 To obtain the best stirring effect. Then, after the system is stabilized by changing the system solid content H in the mixing and stirring tank, sampling is performed from the second mixing and stirring tank 202 or the third mixing and stirring tank 203, and the two-dimensional fractal dimension df corresponding to the system solid content H is measured by using the method for measuring the two-dimensional fractal dimension of the floccule in the sewage, so that a set of data can be obtained, and the system is circulated in this way, so that a plurality of sets of measurement data can be obtained, as shown in fig. 7, and in a preferred embodiment, 5-8 sets of measurement data can be obtained.
In the test process, in order to change the system solid content H in the mixing tank, there are various embodiments, for example, sewage with different water qualities can be introduced into the system, so as to achieve the purpose of changing the system solid content H in the mixing tank, but there is a problem of troublesome operation. In a preferred embodiment, the system solid content H in the mixing and stirring tank can be changed by changing the magnetic mud reflux quantity under the condition that the sewage water quality entering the system is not changed, for example, after the current two-dimensional fractal dimension df is measured, the magnetic mud reflux quantity of the system can be increased, so that the system solid content H of the whole system can be increased to 3000mg/L and kept at a position of 3000mg/L, the two-dimensional fractal dimension df at the moment can be measured, and then the system solid content H of the whole system can be increased to 4000mg/L, 5000mg/L, 6000mg/L, 7000mg/L and the like by increasing the magnetic mud reflux quantity, as shown in fig. 7, so that multiple groups of measurement data can be conveniently and efficiently obtained, and the H-df fitting curve can be more conveniently calculated.
And 3.2, marking each group of measurement data in a plane rectangular coordinate system, and obtaining an H-df fitting curve through data fitting, so that the method is very convenient. Similarly, in this step, the data fitting process may be performed by using existing data processing software, or may be performed manually by using an existing mathematical formula, which is not described herein again, for example, as shown in fig. 7, the H-df fitting curve obtained by using the water sample in the second mixing and stirring tank 202.
3.3 obtaining the optimal solid content range [ a, b ] of the system according to the H-df fitting curve]. Specifically, in one embodiment, the method of calculating the optimal lower solids content limit a is: setting a two-dimensional fractal dimension lower limit df0, and calculating corresponding system solid content H by utilizing an H-df fitting curve or a fitting formula corresponding to the H-df fitting curve 0 Let a=h 0 . Similarly, the method for calculating the optimal upper limit b of the solid content is as follows: setting an upper limit df1 of a two-dimensional fractal dimension, and calculating corresponding system solid content H by utilizing an H-df fitting curve or a fitting formula corresponding to the H-df fitting curve 1 Let b=h 1 The method is very convenient. In implementation, the lower limit df0 of the two-dimensional fractal dimension and the upper limit df1 of the fractal dimension may be determined according to actual requirements, and preferably, the lower limit of the fractal dimension may be set to df0=2; and/or, the upper limit of the fractal dimension may be set to df1=3.
The system solid content is a critical influencing factor for the magnetic base synergistic water treatment technology, and the optimal solid content range of any magnetic coagulation water treatment system can be effectively determined by adopting the method, for example, as shown in the figure, the system solid content is an H-df fitting curve of the magnetic coagulation water treatment system, and as can be seen from fig. 7: the solid content of the system is less than 3000mg/L, the df value is less than 2, the coagulation effect is poor, and most of the system is tiny floccules, which are difficult to agglomerate among particles and grow up because the collision probability of the particles in the coagulation process is low, and the tiny floccules are easily carried out by overflow water of the sedimentation cavity 301, so that the water quality of the water is affected. When the solid content of the system is higher than 6000mg/L, the coagulation effect also tends to be poor, the solid content of the sedimentation cavity 301 is higher, the water discharged from the sedimentation cavity 301 is 'run out', the water quality of the discharged water is influenced, and the impact resistance of the system is reduced. The reason for this is probably that when the solid content of the system is too high, the formed flocks are too much, so that the hydraulic effect is affected, part of the flocks have a descending trend, and the flocks in an ascending trend are collided and scattered in the process. In summary, in the present embodiment, the solid content of the system in the magnetic coagulation water treatment system is preferably controlled to 3000-6000 mg/L, so that the best effect can be obtained.
Step 4, controlling the stirrer 205 to operate at the optimal rotation speed to obtain the optimal stirring effect, and monitoring the system solid content H in the mixing and stirring tank, wherein the system solid content H in the second mixing and stirring tank 202 is generally equal to the system solid content H in the third mixing and stirring tank 203 because the materials in the second mixing and stirring tank 202 and the third mixing and stirring tank 203 are balanced, and in actual operation, the system solid content H in the last mixing and stirring tank (the third mixing and stirring tank 203 in this embodiment) may be monitored. In the running process, when the system solid content H in the mixing and stirring tank fluctuates, the system solid content in the mixing and stirring tank can be regulated by changing the reflux quantity of the magnetic mud, so that the system solid content H is in the optimal solid content range, and the whole system can always run in a state which is most favorable for improving the sewage treatment effect.
In one application scenario of the method, a worker may obtain the current system solid content H of the system by periodically and manually monitoring the system solid content H in the mixing tank, and may compare the current system solid content H of the system with the optimal solid content range of the system, and when the current system solid content H of the system is found to be greater than the optimal solid content upper limit b, the worker may manually adjust the flow control device 304 to reduce the reflux amount of the magnetic mud, and at this time, the flow control device 304 may use a manual valve. Similarly, when the current system solid content H of the system is found to be smaller than the optimal solid content lower limit a, a worker can manually adjust the flow control device 304 to increase the reflux amount of the magnetic mud, so that the system can continuously operate in a mode of being most beneficial to improving the sewage treatment effect all the time, and the system is particularly suitable for occasions with small sewage quality fluctuation.
In another application scenario of the method, in order to accurately control the magnetic mud reflux amount in the operation process of the magnetic coagulation water treatment system, the magnetic coagulation water treatment system is further provided with a controller and a sensor 204, wherein the controller is respectively electrically connected with the sensor 204, the stirrer 205 and the flow control device 304, and the sensor 204 is used for monitoring the system solid content H in the mixing and stirring tank and sending the system solid content H to the controller, as shown in fig. 2-4. The controller can control the reflux amount of the magnetic mud by controlling the flow control device 304, and in this case, the flow control device 304 can preferably adopt an electric controller valve, an electromagnetic valve, a pneumatic valve or the like. The controller can control the rotation speed of the stirrer 205, and the optimal solid content range [ a, b ] of the system can be stored in the controller in advance (can be stored in the controller or a storage connected with the controller), so that the rotation speed of the stirrer 205 can be controlled by the controller during the actual operation of the system, the stirrer 205 can be ensured to operate at the optimal rotation speed, and the sensor 204 can be used for monitoring the solid content H of the system in the mixing stirring tank so as to be compared with the optimal solid content range of the system; when the system solid content H is greater than the upper limit b of the optimal solid content, the controller can reduce the reflux quantity of the magnetic mud through the flow control device 304, so that the system solid content in the mixing and stirring tank is reduced, and the system solid content H is in the optimal solid content range; when the system solid content H is less than the lower limit a of the optimal solid content, the controller can increase the magnetic mud reflux amount through the flow control device 304, thereby increasing the system solid content in the mixing and stirring tank, so that the system solid content H is in the optimal solid content range.
In the implementation, the controller may preferably adopt a PC, a single-chip microcomputer, a PLC, or the like, and of course, the controller may also adopt a DSP, an embedded chip, or the like. The sensor 204 may preferably be a suspended matter on-line monitor (or referred to as a suspended matter on-line monitor), for example, a SIN-PSS100 suspended matter analyzer, a ZWYG-2088T-type on-line sludge concentration meter, a ZWYG-2087A suspended matter on-line analyzer, or the like. Of course, a turbidity meter and the like can be adopted, and only the concentration of suspended matters in the sewage can be monitored.
Example 2
In the magnetic coagulation water treatment system provided in this embodiment 2, a magnetic mud pump 305 may be disposed only downstream of the mud discharging port of the sedimentation device 300, specifically, as shown in fig. 3 or fig. 4, the mud discharging port of the sedimentation device 300 is communicated with the magnetic mud pump 305, the magnetic mud pump 305 is communicated with the flow control device 304, the flow control device 304 is respectively communicated with the coagulation device 200 and the magnetic recovery device 400, and the controller is electrically connected with the flow control device 304 for distributing the reflux amount of the magnetic mud under the control of the controller. The purpose of accurately controlling the reflux quantity of the magnetic mud is achieved. Since the coagulation device 200 and the magnetic recovery device 400 are respectively communicated with the sludge discharge port of the sedimentation device 300 through the flow control device 304, the flow control device 304 is provided with an input end and two output ends, wherein the magnetic sludge pump 305 is communicated with the input end, and the two output ends are respectively communicated with the coagulation device 200 and the magnetic recovery device 400, and when in specific implementation, the flow control device 304 can adopt a cyclone, a three-way regulating valve, a pneumatic three-way regulating valve, an electric three-way regulating valve or the like, so as to accurately control the amount of the backflow magnetic sludge and the amount of the residual magnetic sludge under the control of the controller.
The control method based on the magnetic coagulation water treatment system is the same as that in embodiment 1, and is not repeated here.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention.
Claims (6)
1. The control method based on the magnetic coagulation water treatment system is characterized in that the magnetic coagulation water treatment system comprises a coagulation device for conditioning sewage, a precipitation device for separating magnetic mud, a controller, a sensor and a flow control device, wherein the coagulation device is provided with a mixing and stirring tank, and a stirrer is arranged in the mixing and stirring tank; the mixing and stirring tank is communicated with the sedimentation device, and a mud discharge port of the sedimentation device is communicated with the mixing and stirring tank and is used for refluxing magnetic mud; the controller is electrically connected with the sensor, the stirrer and the flow control device respectively, and the flow control device is arranged on a communication path between the sludge discharge port and the coagulation device; the method comprises the following steps:
step 2, calculating the optimal stirring strength G of the mixing and stirring pool 0 Calculating the optimal rotation speed of the stirrer according to the optimal stirring intensity; wherein, calculate the optimal stirring intensity G 0 The method of (1) is as follows: 2.1, taking the rotating speed of the stirrer as a variable, examining the two-dimensional fractal dimension df of floccules in sewage under different G values by changing the rotating speed of the stirrer, and obtaining at least three groups of measurement data taking the G value as an abscissa and taking the df as an ordinate; step 2.2, marking each group of measurement data in a plane rectangular coordinate system, and obtaining a G-df fitting curve through data fitting; step 2.3, obtaining the optimal stirring strength G according to the G-df fitting curve 0 ；
The method for measuring the two-dimensional fractal dimension df of the flocculating body in the sewage comprises the following steps: firstly, taking a proper amount of coagulated suspension from a mixing and stirring tank and placing the suspension on a glass slide; measuring L and A of at least two floccules under a microscope to obtain at least two groups of data points taking lnL as an abscissa and lnA as an ordinate, wherein A is a projection surface of the floccules, and L is the maximum perimeter of projection; finally, each group of data points are subjected to linear fitting, and the slope of the fitted straight line is the two-dimensional fractal dimension df;
step 3, at the optimal stirring intensity G 0 The optimal solid content range [ a, b ] of the computing system ]；
Step 4, using a controller to control the stirrer to run at the optimal rotation speed, and using a sensor to monitor the solid content H of the system in the mixing and stirring tank; when the system solid content H is larger than the upper limit b of the optimal solid content, the controller reduces the reflux quantity of the magnetic mud by controlling the flow control device so as to reduce the system solid content in the mixing and stirring tank and enable the system solid content H to be in the optimal solid content range; when the system solid content H is smaller than the lower limit a of the optimal solid content, the controller improves the magnetic mud reflux quantity by controlling the flow control device so as to increase the system solid content in the mixing and stirring tank and enable the system solid content H to be in the optimal solid content range.
2. The method for controlling a magnetic coagulation water treatment system according to claim 1, further comprising the steps of 1, determining pool shape parameters of a mixing pool in a coagulation device, and determining size structural parameters of a stirrer according to the pool shape parameters and design specifications, wherein the size structural parameters at least comprise blade diameters, blade numbers and blade widths.
3. The method according to any one of claims 1-2, wherein in step 3, an H-df fitting curve is calculated, and the optimal solid content range [ a, b ] is obtained by the H-df fitting curve, wherein H represents the solid content of the system, and df represents the two-dimensional fractal dimension of the floccules in the wastewater.
4. A control method based on a magnetic coagulation water treatment system according to claim 3, wherein the method of calculating the optimal solid content range [ a, b ] in step 3 is as follows:
step 3.1, maintaining the stirring strength of the mixing and stirring tank to be G 0 Taking the system solid content H in the mixing and stirring tank as a variable, examining the two-dimensional fractal dimension df of the floccules in the sewage under the condition of the same stirring strength by changing the system solid content H in the mixing and stirring tank, and obtaining at least three groups of measurement data taking H as an abscissa and df as an ordinate;
step 3.2, marking each group of measurement data in a plane rectangular coordinate system, and obtaining an H-df fitting curve through data fitting;
and 3.3, obtaining the optimal solid content range [ a, b ] of the system according to the H-df fitting curve.
5. The method of controlling a magnetic coagulation water treatment system according to claim 4, wherein in step 3.3, the method of calculating the optimal lower solid content limit a is: setting a two-dimensional fractal dimension lower limit df0, and calculating corresponding system solid content H by utilizing an H-df fitting curve or a fitting formula corresponding to the H-df fitting curve 0 Let a=h 0 ；
And/or, the method for calculating the optimal solid content upper limit b is as follows: setting an upper limit df1 of a two-dimensional fractal dimension, and calculating corresponding system solid content H by utilizing an H-df fitting curve or a fitting formula corresponding to the H-df fitting curve 1 Let b=h 1 。
6. A control method based on a magnetic coagulation water treatment system according to claim 3, wherein the flow control device adopts a control valve;
and/or the controller is a PC, a singlechip or a PLC;
and/or the sensor adopts a suspended matter on-line monitor.
Priority Applications (1)
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20140042975A (en) * | 2012-09-28 | 2014-04-08 | (주)비드앤마이크로 | Method and apparatus for high-rate coagulative precipitation using polymer beads containing magnetic material |
| CN107324465A (en) * | 2017-07-24 | 2017-11-07 | 温州大学 | A kind of integrated Waste Water Treatment of magnetic-coagulation and method |
| CN112591952A (en) * | 2020-11-06 | 2021-04-02 | 中能化江苏地质矿产设计研究院有限公司 | System for coal fired power plant desulfurization waste water is handled to magnetism coagulation |
| CN213865812U (en) * | 2020-12-14 | 2021-08-03 | 中建环能工程设计研究有限公司 | Automatic control system for magnetic precipitation sewage treatment |
| CN114180689A (en) * | 2021-11-24 | 2022-03-15 | 南京信息工程大学 | Magnetic coagulation water treatment method for in-situ magnetic seed separation and reuse |
-
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20140042975A (en) * | 2012-09-28 | 2014-04-08 | (주)비드앤마이크로 | Method and apparatus for high-rate coagulative precipitation using polymer beads containing magnetic material |
| CN107324465A (en) * | 2017-07-24 | 2017-11-07 | 温州大学 | A kind of integrated Waste Water Treatment of magnetic-coagulation and method |
| CN112591952A (en) * | 2020-11-06 | 2021-04-02 | 中能化江苏地质矿产设计研究院有限公司 | System for coal fired power plant desulfurization waste water is handled to magnetism coagulation |
| CN213865812U (en) * | 2020-12-14 | 2021-08-03 | 中建环能工程设计研究有限公司 | Automatic control system for magnetic precipitation sewage treatment |
| CN114180689A (en) * | 2021-11-24 | 2022-03-15 | 南京信息工程大学 | Magnetic coagulation water treatment method for in-situ magnetic seed separation and reuse |
Non-Patent Citations (1)
| Title |
|---|
| 吕淼."磁介体强化混凝处理城市河道水的试验研究"，中国优秀硕士学位论文全文数据库工程科技Ⅰ辑，(月刊).2017,12、19-20、37-39. * |
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