JP6941783B2 - Operation control method of coagulant dissolving device - Google Patents

Description

The present invention is an operation control method of a coagulant dissolving device that controls a coagulant dissolving device according to the state of the dissolved liquid after dissolution in a coagulant dissolving device that continuously dissolves a powdery polymer coagulant in a liquid. Regarding.

Conventionally, sludge generated from a sewage treatment plant or the like is dehydrated and treated by a sludge dewatering device or the like. By adding a polymer flocculant to these sludges and mixing (mixing), the sludge suspended in the undiluted solution is aggregated to form strong flocs, and the aggregated sludge is supplied to a dehydrator for dehydration treatment. doing. As the polymer flocculant, powdery ones are often used from the viewpoint of cost. The powdery polymer flocculant is dissolved in a predetermined concentration and then mixed with sludge to coagulate.

Patent Document 1 describes a primary treatment unit that produces a primary treatment liquid in which a polymer flocculant is agitated and dispersed in a liquid in a system that continuously dissolves a powdery polymer flocculant in a liquid, and a primary treatment liquid. Disclosed is a coagulant dissolving apparatus having a secondary treatment unit that rapidly grinds the secondary treatment liquid with a pair of rotating disks to generate a secondary treatment liquid, and a tertiary treatment unit that completely dissolves the secondary treatment liquid while stirring.

Patent Document 2 describes a coagulant injection control method for adjusting the amount of the coagulant added and the rotation speed of the stirrer by photographing the coagulated state of the coagulated flocs generated by adding a coagulant to a stock solution such as sewage sludge. It is disclosed.

Japanese Unexamined Patent Publication No. 2014-200695 Japanese Unexamined Patent Publication No. 2005-7338

If the solution is left for a long time, the solution tends to deteriorate and the aggregation performance tends to deteriorate. Therefore, it is necessary to continuously dissolve the solution in a short time immediately before use.
The invention of Patent Document 1 is a coagulant dissolving device that dissolves a powdery polymer coagulant in water by grinding with a pair of rotating discs. Due to humidity, clogging of the supply nozzle, etc., the state of the dissolved liquid after formation fluctuated, and undissolved lumps (mamaco) whose surface was swollen may be generated in a part of the dissolved liquid.

Therefore, the invention of Patent Document 2 discloses a method of recognizing a state after sludge modification by an image and controlling the addition amount of a flocculant and the rotation speed of a stirrer so as to obtain a predetermined state. An object of the present invention is to generate agglomerated flocs of a predetermined area, and the action is different from that of the present invention in which a system is controlled to prevent the generation of foreign matter (undissolved lumps).

In addition, Patent Document 1 describes that a part of the dissolution liquid generated by the coagulant dissolving apparatus is stored in a measuring tank, the viscosity is measured, and the rotation speed of the rotating disk is adjusted according to the measurement result. However, the viscosity does not fluctuate significantly when undissolved lumps are generated, and the accuracy of the measuring device for continuously measuring the viscosity is low.

The present invention is a coagulant dissolving device that continuously dissolves a powdery polymer coagulant in a liquid. Provided is an operation control method of a coagulant dissolving device that stably dissolves a polymer flocculant by adjusting the above.

In the present invention, a powdery polymer flocculant is mixed with a liquid supplied from a liquid supply source in a stirring tank of a primary treatment unit, and a primary treatment liquid is prepared by a pulverizer equipped with a rotating disk of the secondary treatment unit. In the operation control method of the coagulant dissolving device that grinds and dissolves while grinding, the standard cumulative number of undissolved lumps generated in the solution previously treated by the coagulant dissolving device, the maximum / minimum rotation speed of the crushing device, and the stepwise If the cumulative number of undissolved lumps is less than the standard cumulative number, the operation of each device is maintained in the current state, and the cumulative number of undissolved lumps is equal to or greater than the standard cumulative number. In the case of
Similarly, when the above number is used as the area, the pulverizer can be controlled according to the size of the undissolved mass to improve the dissolution efficiency.

A reference time is set in which the undissolved mass is not detected for a predetermined time, and if the undissolved mass is not detected, the continuous time in which the undissolved mass is not detected is calculated, and the time during which the undissolved mass is not detected is longer than the predetermined reference time. If it is short, the operation of each device is maintained in the current state, and if the time for not detecting undissolved lumps is equal to or longer than the predetermined reference time, the disk rotation speed of the crusher is gradually reduced by the rotation speed width. Therefore, it is possible to reduce the electricity bill.

The disk rotation speed of the crusher is gradually increased by the rotation speed width, and when the disk rotation speed becomes larger than the predetermined maximum rotation speed, an alarm is issued or the operation of the coagulant dissolving device is automatically stopped. And the safety of the entire processing system is improved.

In the present invention, the coagulant dissolving device is controlled according to the condition of the dissolved liquid after dissolution, and the expensive polymer coagulant is surely ground and dissolved at a constant concentration, and sludge is stably coagulated and dehydrated. It becomes possible to do. Even if the aggregation is poor when undissolved, the rotation speed of the crushing device is automatically controlled without stopping the device and inspecting by the staff, which can contribute to improving the reliability of the entire processing system. In addition, the electricity bill can be reduced because the control for reducing the rotation speed of the crushing device is also used.

It is a flow chart of the melting system which concerns on this invention. Similarly, it is a vertical sectional view of a secondary processing section and a tertiary processing section. Similarly, it is a flowchart of an operation control system. It is a flowchart of the operation control system of another Example.

FIG. 1 is a flow chart of a melting system according to the present invention.
The coagulant dissolving device 8 is composed of a unit having a primary processing unit S1, a secondary processing unit S2, and a tertiary processing unit S3.
The primary processing unit S1 is a stirring tank, and the powdery polymer flocculant stored in the powder feeding device 1 and the liquid supplied from the liquid feeding source 2 are mixed in the stirring tank 3. The polymer flocculant dispersed and swollen while being stirred in the stirring tank 3 is transferred to the secondary treatment unit S2 by the primary treatment liquid transfer pump 5 interposed in the primary treatment liquid transfer pipe 4.

The secondary treatment unit S2 is a pulverizer 6, which pulverizes and dissolves the high-viscosity primary treatment liquid while grinding it. The pulverized and dissolved secondary treatment liquid is discharged to the tertiary treatment unit S3.

The tertiary treatment unit S3 is a dissolution chamber 7, and the undissolved portion that has not been pulverized and dissolved in the secondary treatment unit S2 is completely dissolved. After that, the dissolution liquid is transferred from the coagulant dissolving device 8 to the coagulator 10 via the discharge pipe 9.

The powdery polymer flocculant and the liquid supplied from the liquid supply source 2 are supplied in a fixed amount according to the sludge properties, and a solution having a constant concentration is generated.

The sludge is stored in the sludge storage tank 11, and is supplied from the sludge supply pipe 12 to the coagulation device 10 via the sludge supply pump 14. In the aggregating device 10, the solution transferred from the aggregating agent dissolving device 8 is added and mixed with the sludge to form a strong agglomerating floc. The agglomerated flocs formed by the aggregating device 10 are supplied to the dehydrator 50 via the agglomerating sludge supply pipe 13 to perform solid-liquid separation, and produce dehydrated sludge having a low water content.

The discharge pipe 9 is provided with an autopsy window 51 so that the state of the dissolved liquid flowing in the pipe can be visually observed from the outside. An image sensor 52 is located in front of the inspection window 51, and photographs the state of the dissolved liquid flowing in the discharge pipe 9. The image data captured by the image sensor 52 is transmitted to the control device 53. The control device 53 compares the preset reference value with the image data transmitted from the image data, and then adjusts the rotation speed of the crushing device 6 as necessary.

Since the undissolved mass is solidified in a powdery state at the center and becomes cloudy, there is a difference in shade when a black-and-white image is taken. The properly dissolved solution is colorless and transparent, and the cloudy undissolved mass is detected thicker than the surroundings.

The image sensor 52 may take a picture by connecting a transparent bypass pipe to the discharge pipe 9, introducing a part of the solution flowing down the discharge pipe 9 into the bypass pipe, and taking a picture with the bypass pipe. Alternatively, a part of the solution flowing down the discharge pipe 9 may be supplied to a storage tank for photographing and photographed in the storage tank.

FIG. 2 is a vertical cross-sectional view of the secondary treatment section and the tertiary treatment section, and the other end of the primary treatment liquid transfer pipe 4 for transferring the primary treatment liquid from the stirring tank 3 is connected to the secondary treatment section S2. The crushing device 6 of the secondary processing unit S2 rotatably faces a disk-shaped disk having a conical recess 24 formed inside from the outer peripheral portion toward the center. One of the discs is a fixed disc 25, and the primary treatment liquid is supplied to the inside from the supply port 26 provided in the central portion. The primary treatment liquid transfer pipe 4 is connected to the supply port 26 of the fixed disk 25. The other disc is a rotating disc 27, which is connected to a rotating shaft 29 having an electric motor 28 at the other end. The intermediate portion of the rotating shaft 29 is rotatably supported by a bearing 30 as appropriate.

The volume of the central portion of the opposing disks 25 and 27 is large, and the volume becomes smaller toward the outer periphery. A predetermined gap is provided at the outer peripheral end, and the primary treatment liquid supplied to the central portion is transferred to the outer peripheral side by the press-fitting pressure of the primary treatment liquid transfer pump 5 and the centrifugal action of the rotating disc 27, and the inner surfaces of the discs 25 and 27. Is crushed and dissolved in. The vicinity of the outer peripheral edge may be formed of a flat surface. The gap at the outer peripheral edge is set to 1 mm or less.

The materials of the disks 25 and 27 are not limited as long as they are not modified in the polymer solution such as metal, resin and ceramics. The contact surfaces of the fixed disc 25 and the rotating disc 27 are provided with rough and minute irregularities to impart a frictional effect to the liquid to be treated passing through the gaps, thereby increasing the pulverizing and dissolving actions.

The casing 34 is configured so as to surround the pair of discs 25 and 27. The fixed disc 25 is fixed to the inner wall surface of the casing 34. A melting chamber 7 of the tertiary processing unit S3 having a predetermined distance is formed between the outer peripheral surfaces of the disks 25 and 27 and the inner peripheral surface of the casing 34. A discharge pipe 9 is connected to the top of the tertiary processing unit S3, and a drain pipe 35 is connected to the bottom. The primary treatment liquid transfer pipe 4 penetrates the casing 34 and communicates with the inside of the fixed disk 25. The rotating shaft 29 is water-sealed by a well-known technique.

In this embodiment, the casing 34 and the electric motor 28 are mounted on a common pedestal 36, but the electric motor 28 may be an integrated type fixed to the casing 34. Further, although the rotating disk 27 connected to the rotating shaft 29 on the horizontal axis is configured to rotate in the vertical direction, the rotating disk 27 may rotate in the horizontal direction with the rotating shaft 29 as the vertical axis.

The tertiary processing unit S3 is formed of a cylindrical melting chamber 7 having a predetermined distance between the outer peripheral surfaces of the pair of discs 25 and 27 and the casing 34, and is ground by the discs 25 and 27 of the secondary processing unit S2. The secondary treatment liquid is discharged to the dissolution chamber 7. The outer wall of the melting chamber 7 is composed of a casing 34 that surrounds the melting chamber 7 along the disc. Since the discharge pipe 9 connected to the melting chamber 7 is connected to the top of the casing, the pair of discs 25 and 27 always rotate in a submerged state. Since the secondary treatment unit S2 is completely submerged, the secondary treatment liquid discharged from the secondary treatment unit S2 does not collide with the inner wall of the tertiary treatment unit S3 to generate bubbles. Therefore, the labor of the defoaming treatment in the subsequent stage can be saved, and the discharge amount of the tertiary treatment liquid can be accurately measured.

Due to the rotational force of the rotating disk 27, the treatment liquid in the dissolution chamber 7 is water-stirred along the casing 34 to completely dissolve the slightly remaining undissolved component. A back blade may be provided on the back surface of the rotating disc 27 to increase the stirring action.

FIG. 3 is a flowchart of the operation control system.
A1. Setting The reference cumulative number K0 of undissolved lumps generated in the solution treated by the coagulant dissolving device 8 in advance, the maximum rotation speed Nmax and the minimum rotation speed Nmin of the rotating disk 27 of the crushing device 6, and the rotations that are gradually increased or decreased. A number width n and a reference time T in which an undissolved mass is not detected for a predetermined time are set.
Further, the resolution of the image sensor 52, the imaging interval, the area definition of the undissolved mass, and the like may be appropriately set according to the processing system or the processing sludge.

B1. Start of operation The rotation disk 27 is started to operate the coagulant dissolving device 8 at a predetermined reference rotation speed.

C1. Imaging The dissolution liquid discharged from the coagulant dissolving apparatus 8 is photographed at a predetermined imaging interval of the image sensor 52. The shooting data is transmitted to the control device 53. The image is analyzed by the control device 53 to detect an undissolved mass.
In this embodiment, shooting is continuously performed.

D1. Cumulative number of undissolved lumps When the cumulative number K of undissolved lumps detected by the control device 53 is less than the reference cumulative number K0, the process proceeds to flowchart C1, the operation of each device is maintained in the current state, and the image sensor. Continue shooting with 52.
When the cumulative number K of undissolved lumps detected by the control device 53 becomes the reference cumulative number K0 or more, the process proceeds to the flowchart E1 and control is performed to gradually increase the disk rotation speed by the rotation speed width n.
When the cumulative number K is 0 in the control device 53, that is, when the undissolved mass is not detected, the process proceeds to the flowchart H1 and the continuous time not detected is calculated.

For example, when the reference cumulative number K0 is set to 1, the flow chart E1 is immediately displayed when an undissolved mass is detected, and when the reference cumulative number K0 is set to 5, 5 undissolved masses are detected. Operate while maintaining the current status.

E1. In the maximum rotation speed comparison flowchart D1, when the cumulative number K of undissolved lumps detected by the control device 53 becomes the reference cumulative number K0 or more, the disk rotation speed is gradually increased in order to increase the rotation speed width n. The rotation speed N + n in consideration of the rotation speed width n to be performed is compared with the preset maximum rotation speed Nmax.
If the changed rotation speed N + n is smaller than the maximum rotation speed Nmax, the process proceeds to the flowchart F1 and control is performed to gradually increase the rotation speed width n set in advance.
When the changed rotation speed N + n becomes the maximum rotation speed Nmax or more, the process shifts to the flowchart G1 to issue an alarm or control to automatically stop the operation of the coagulant dissolving device 8.

F1. In the rotation speed increase flowchart E1, when the changed disk rotation speed N + n is smaller than the maximum rotation speed Nmax, control is performed to increase the rotation speed by a preset rotation speed width n. After increasing the rotation speed, the cumulative number of undissolved lumps is reset to 0, the process shifts to the flowchart C1 and the image sensor 52 resumes photographing.

G1. In the alarm flowchart E1, when the changed disk rotation speed N + n becomes the maximum rotation speed Nmax or more, an alarm is issued or control is performed to automatically stop the operation of the coagulant dissolving device 8.

H1. In the time comparison flowchart D1, when the undissolved mass is not detected by the control device 53, the continuous time T that is not detected is calculated.
When the time T in which the undissolved mass is not detected is shorter than the predetermined reference time T0, the process proceeds to the flowchart C1, the operation of each device is maintained in the current state, and the image sensor 52 continues shooting.
When the time T in which the undissolved mass is not detected is equal to or longer than the predetermined reference time T0, the process proceeds to the flowchart I1 and the disk rotation speed is controlled to be gradually reduced by the rotation speed width n.

I1. In the minimum rotation speed comparison flowchart H1, when the time T in which the undissolved mass is not detected is equal to or longer than the predetermined reference time T0, the rotation speed width n is gradually reduced in order to reduce the disk rotation speed by the rotation speed width n. The rotation speed Nn in consideration of the above is compared with the preset minimum rotation speed Nmin.
When the changed rotation speed N−n is larger than the minimum rotation speed Nmin, the process proceeds to the flowchart J1 and control is performed to gradually reduce the rotation speed width n set in advance.
When the changed rotation speed Nn is equal to or less than the minimum rotation speed Nmin, the process proceeds to the flowchart C1, the operation of each device is maintained in the current state, and the image sensor 52 continues shooting. In the above case, the process may proceed to the flowchart K1 and control may be performed to issue an alarm or automatically stop the operation of the coagulant dissolving device 8.

J1. In the rotation speed reduction flowchart I1, when the changed disk rotation speed N−n is larger than the minimum rotation speed Nmin, control is performed to reduce the rotation speed by a preset rotation speed width n.

K1. In the alarm flowchart I1, when the changed disk rotation speed Nn becomes the minimum rotation speed Nmin or less, an alarm is issued or control is performed to automatically stop the operation of the coagulant dissolving device 8.

FIG. 4 is a flowchart of the operation control system of another embodiment.
FIG. 3 shows that the disk rotation speed is controlled according to the number of undissolved lumps, but FIG. 4 differs in that the disk rotation speed is controlled according to the area of the undissolved lumps. The differences are excerpted and described below.

A2. Setting The reference cumulative area S0 of the undissolved mass generated in the solution treated by the coagulant dissolving device 8 is set in advance.

D2. Cumulative area of undissolved mass When the cumulative area S of undissolved mass detected by the comparison control device 53 is smaller than the reference cumulative area S0, the process proceeds to flowchart C2, the operation of each device is maintained in the current state, and the image sensor. Continue shooting with 52.
When the cumulative area S of the undissolved mass detected by the control device 53 becomes the reference cumulative area S0 or more, the process proceeds to the flowchart E2, and the disk rotation speed is controlled to be gradually increased by the rotation speed width n.
When the cumulative area S is 0 in the control device 53, that is, when the undissolved mass is not detected, the process proceeds to the flowchart H2, and the undetected continuous time T is calculated.

The other flowcharts B2, C2, E2 and K2 are the same as those of B1, C1 and E1 to K1 in FIG. 3, respectively.

The operation control method of the coagulant dissolving device of the present invention automatically controls the coagulant dissolving device according to the state of the dissolved liquid after dissolution to stably generate a polymer dissolution liquid having a constant concentration. It is very effective for treatment systems that use a flocculant for a long period of time, especially for treatment systems that use a continuous dehydrator.

2 Liquid supply source 3 Stirring tank 6 Crushing device 7 Dissolving chamber 8 Coagulant dissolving device 27 Rotating disk S1 Primary processing unit S2 Secondary processing unit S3 Secondary processing unit K0 Reference cumulative number S0 Reference cumulative area T0 Undissolved mass detected for a predetermined time No reference time Nmax Maximum rotation speed Nmin Minimum rotation speed n Rotation speed width to be increased or decreased in stages

Claims (4)

The powdery polymer flocculant is mixed with the liquid supplied from the liquid supply source (2) in the stirring tank (3) of the primary processing unit (S1), and the rotating disk (S2) of the secondary processing unit (S2) is mixed. In the operation control method of the coagulant dissolving device which grinds and dissolves the primary treatment liquid while grinding with the crushing device (6) provided with 27).
The reference cumulative number (K0) of undissolved lumps generated in the lysate previously treated with the coagulant solubilizer (8), and
The maximum and minimum rotation speeds (Nmax and Nmin) of the crusher (6) and the rotation speed width (n) that is gradually increased or decreased,
Set and
If the cumulative number of undissolved lumps (K) is less than the standard cumulative number (K0), maintain the operation of each device in the current state.
When the cumulative number (K) of undissolved lumps exceeds the reference cumulative number (K0), the disk rotation speed of the crushing apparatus (6) is gradually increased by the rotation speed width (n). Operation control method for coagulant solubilizer. The powdery polymer flocculant is mixed with the liquid supplied from the liquid supply source (2) in the stirring tank (3) of the primary processing unit (S1), and the rotating disk (S2) of the secondary processing unit (S2) is mixed. In the operation control method of the coagulant dissolving device which grinds and dissolves the primary treatment liquid while grinding with the crushing device (6) provided with 27).
The reference cumulative area (S0) of the undissolved mass generated in the dissolution liquid previously treated by the coagulant dissolution apparatus (8), and
The maximum and minimum rotation speeds (Nmax and Nmin) of the crusher (6) and the rotation speed width (n) that is gradually increased or decreased,
Set and
If the cumulative area (S) of the undissolved mass is less than the standard cumulative area (S0), maintain the operation of each device in the current state.
When the cumulative area (S) of the undissolved mass becomes equal to or larger than the reference cumulative area (S0), the disk rotation speed of the crushing apparatus (6) is gradually increased by the rotation speed width (n). Operation control method of coagulant dissolving device. A reference time (T0) at which the undissolved mass is not detected for a predetermined time is set, and the undissolved mass is not detected for a predetermined time.
If no undissolved mass is detected, calculate the undetected continuous time (T) and
If the time (T) at which the undissolved mass is not detected is shorter than the predetermined reference time (T0), the operation of each device is maintained in the current state.
When the time (T) at which the undissolved mass is not detected is equal to or longer than the predetermined reference time (T0), the disk rotation speed of the crushing apparatus (6) is gradually reduced by the rotation speed width (n). The operation control method of the coagulant dissolving device according to claim 1 or 2. When the disk rotation speed of the crushing device (6) is gradually increased by the rotation speed width (n) and the disk rotation speed becomes larger than the predetermined maximum rotation speed (Nmax),
The operation control method for a coagulant dissolving device according to any one of claims 1 to 3, wherein an alarm is issued or the operation of the coagulant dissolving device (8) is automatically stopped.

Images