JPH07289950A - System and method for operation of centrifugal cleaner - Google Patents

Abstract

PURPOSE:To provide the quality of an outlet liquid so as to be within a specified range by preventing the variation of water of outlet liquid following the variation of condition of feed liquid. CONSTITUTION:The quality of outlet liquid from a centrifugal cleaner 1 is measured, and the number of rotations of a motor 2 is controlled so as to provide the concentration of an aimed substance comes into a specified range. A device of finding the number of rotations of the motor 2 from the outlet liquid flow rate and the aimed substance concentration is disposed on a concentration measuring instrument 7 for measuring the quality of outlet liquid, and the number of rotations of the motor 2 is controlled on line. In the case the feed liquid flow rate and the feed liquid composition are varied, the variation is sensed by the concentration measuring instrument 7 and the number of rotations of the motor 2 is controlled to set the quality of outlet liquid from a clean liquid line 9 within the specified range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operating system of a centrifugal clarifier for separating a solid content in a liquid by a centrifugal force and an operating method thereof.

[0002]

2. Description of the Related Art As is well known, a centrifugal clarifier supplies a liquid to be separated (also referred to as a supply liquid) containing solids and the like into a bowl which is rotating at a high speed to remove solids contained in the liquid to be separated. It is a device for centrifuging into a clear liquid. The centrifugal clarification machine is provided with a motor for rotating the bowl, a feed line for supplying the liquid to be separated into the bowl, and a clarification line for flowing out the clarification liquid separated in the bowl.

[0003]

The conventional centrifugal clarifier does not control the concentration of the components in the feed solution to keep the concentration of the components in the clarification liquid within a certain range. That is, the operation method of the centrifugal clarifier is such that the bowl is rotated at a certain number of rotations to collect the solid content and suppress the concentration of the clarified liquid to a low level.

Therefore, when the centrifugal clarifier is operated without controlling the component concentration of the clarified liquid, the composition of the clarified liquid, that is, the composition of the clarified liquid, that is, fluctuations in the supply flow rate and component concentration, fluctuations in the number of rotations of the bowl, etc. However, there is a problem that the component concentration fluctuates.

The present invention has been made to solve the above problems, and provides an operating system of a centrifugal clarifier capable of keeping the concentration of components in a clarified liquid within a certain range, and an operating method thereof. The purpose is to do.

[0006]

According to the present invention, a flow rate control valve, a concentration / particle size distribution measuring instrument and a flow meter are provided in a feed line of a centrifugal clarifier, and the concentration is measured in the clarifier line of the centrifugal clarifier. A centrifuge, a motor is connected to the bowl in the centrifugal clarifier through a rotation shaft, and a controller having a clarification model for inputting the number of rotations of the motor is provided, and the flow control valve and the concentration particle are provided in the controller. It is characterized by connecting a signal cable for inputting the measured values of the diameter distribution measuring instrument, the flowmeter and the concentration measuring instrument.

Further, according to the present invention, a supply liquid containing solids and the like is supplied to a bowl in the centrifugal clarifier through a liquid supply line of the centrifugal clarifier, and centrifugally separated in the bowl to remove the solids and the like. In the operating method of the centrifugal clarifier, in which the clarified liquid flowing out from the bowl is discharged from the clarified liquid line of the centrifugal clarifier, the feed liquid flow rate, the rotation speed of the motor for rotating the bowl, the component concentrations of the feed liquid and the clarified liquid are It is characterized in that it is measured online and the flow rate of the supply liquid is adjusted so that the concentration of the solid content or the like in the clarified liquid falls within a certain range.

[0008]

The rotation speed of the motor of the centrifugal fining device, that is, the bowl, the flow rate of the feed liquid, the particle size distribution of the components of the feed liquid, and the component concentrations of the feed liquid and the clarification liquid are measured online. Even if the component concentration of the supply liquid changes, the flow rate of the supply liquid is adjusted or the number of rotations of the bowl is adjusted so that the component concentration of the clear liquid falls within a certain range.

The controller having the fining model shown in FIG. 2 predicts the component concentration in the fining liquid by using the feed liquid flow rate, the component concentration in the feed liquid, and the particle size distribution. In FIG. 2, the horizontal axis represents the particle size distribution and the vertical axis represents the partial collection efficiency, showing the collection efficiency for each particle size of the solid content in the feed liquid. The control device is determined by the three factors of the supply liquid flow rate, bowl rotation speed, and solid content density.
The correlation is input, and the optimum correlation is selected from among them, and the solid content concentration of the clarified liquid is predicted using the particle size distribution of the feed liquid.

That is, when the supply flow rate, bowl rotation speed, and solid content density are determined, the solid content concentration in the clarified liquid can be predicted from the solid content concentration in the supply liquid and the particle size distribution. The supply flow rate or bowl rotation speed is controlled so that this predicted value falls within a certain range.

FIG. 3 shows a comparison between the conventional example of the clarified liquid and the embodiment of the present invention when the supply liquid concentration is changed. As is clear from FIG. 3, there is no change in the concentration of the clarified liquid depending on the elapsed time.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the operating system of a centrifugal clarifier according to the present invention will be described with reference to FIG. 1 is a block system diagram of this embodiment.

In FIG. 1, reference numeral 1 is a centrifugal clarifier, and a bowl (not shown) is provided in the centrifugal clarifier 1. The bowl is connected to a rotary shaft that is directly connected to the motor 2, and is rotated at a high speed by driving the motor 2. The bowl is provided with an inlet for the feed liquid flowing in from the feed liquid line 8 and an outlet for letting out the centrifugally separated clear liquid and connecting it to the clear liquid line 9.

A flow rate control valve 6.
A concentration / particle size distribution measuring device 3 and a flowmeter 4 are connected in order from the upstream side, and a clarification liquid line 9 is connected to a concentration measuring device 7.

In the figure, reference numeral 5 is a control device, and this control device 5 has the fining model shown in FIG. 2, and has a flow control valve 6, a concentration particle size distribution measuring instrument 3, a flow meter 4 and A signal cable (indicated by a broken line in FIG. 1) of the concentration measuring device 7 is connected. The concentration / particle size distribution measuring device 3 measures the concentration and particle size distribution of the solid content in the supply liquid, the flow meter 4 measures the supply liquid flow rate, and the flow control valve 6 operates the supply liquid flow rate. The concentration measuring device 7 is a water quality measuring device for measuring the solid content concentration in the clear liquid.

According to the operation system having the above-mentioned configuration, in a centrifugal clarifier for removing solids and the like from a liquid containing solids and the like, the flow rate of the supply liquid, the number of rotations of the bowl, the component concentrations of the supply liquid and the clarification liquid are measured online. By adjusting the flow rate of the supply liquid or adjusting the bowl rotation speed, the concentration of solids and the like in the clarified liquid can be kept within a certain range.

Next, an embodiment of the method of operating the centrifugal clarifier using the operating system of the centrifugal clarifier according to the above embodiment will be described.

(First Embodiment of Operating Method) This embodiment is an example in which when the solid content concentration in the supply liquid fluctuates, the supply flow rate is adjusted accordingly to keep the solid content concentration of the clarified liquid within a certain range. is there.

First, the solid content concentration and particle size distribution in the supply liquid are measured online by the concentration / particle size distribution measuring device 3. The supply liquid flow rate is measured online with the flow meter 4. Next, the controller 5 having the fining model shown in FIG. 2 selects the optimum particle size-partial collection efficiency relationship from the measured values of the feed liquid flow rate, the solid content concentration in the feed liquid, and the particle size distribution. Predict the solids concentration in the clarified liquid.

When the prediction of the solid content concentration in the clarified liquid is out of a certain range, the control device 5 operates the flow rate control valve 6 to change the supply flow rate as the operating condition. By changing the flow rate of the supplied liquid, a correlation between the particle size and the partial collection efficiency different from the correlation in FIG. 2 is obtained, and the solid content concentration in the clarified liquid is newly predicted. This operation is repeated so that the solid content concentration in the clarified liquid falls within a certain range.

Next, the solid content concentration in the clarified liquid is measured online by the concentration measuring device 7. The solid content concentration of the clear liquid predicted by the control device 5 is compared with the solid content concentration of the clear liquid actually measured by the concentration measuring device 7.

The experimental results according to the above embodiment are shown in FIG.
When the solid content concentration of the supply liquid was increased during the clarification operation, the solid content concentration of the clarification liquid could be kept within a certain range by adjusting the supply flow rate as shown in FIG. On the other hand, in the conventional example, since the supply flow rate was not adjusted, the supply flow rate increased in accordance with the solid content concentration.

(Embodiment 2 of Operating Method) In this embodiment, when the solid content concentration in the feed liquid fluctuates, the bowl rotation speed is adjusted accordingly to keep the solid content concentration of the clarified liquid within a certain range. Is.

The solid content concentration and the particle size distribution in the supply liquid are
The measurement is performed online with the particle size distribution measuring device 3. The supply liquid flow rate is measured online with the flow meter 4.

As in Example 1, the controller 5 having the fining model shown in FIG. 2 was used to determine the solid content concentration in the fining liquid by using the feed liquid flow rate, the solid content concentration in the feed liquid, and the particle size distribution. Predict.

When the prediction of the solid content concentration in the clarified liquid is out of the certain range, the control device 5 operates the motor 2 to change the bowl rotation speed as an operating condition. By changing the bowl rotation speed, a correlation between the particle size and the partial collection efficiency, which is different from the correlation in FIG. 2, is obtained, and the solid content concentration in the clarified liquid is newly predicted. This operation is repeated so that the solid content concentration in the clarified liquid falls within a certain range.

The solid content concentration in the clarified liquid is measured online by the concentration measuring device 7. The solid content concentration of the clear liquid predicted by the control device 5 is compared with the solid content concentration of the clear liquid actually measured by the concentration measuring device 7. According to this example, almost the same data as in Example 1 was obtained.

(Embodiment 3 of Operating Method) In this embodiment, when the particle size distribution of the solid content in the supply liquid changes, the supply flow rate is adjusted accordingly to keep the solid content concentration of the clarified liquid within a certain range. It is an example.

The solid content concentration and the particle size distribution in the supply liquid are
The measurement is performed online with the particle size distribution measuring device 3. The supply liquid flow rate is measured online with the flow meter 4. As in Example 1, the controller 5 having the clarification model shown in FIG. 2 predicts the solid content concentration in the clarified liquid by using the feed liquid flow rate, the solid content concentration in the supply liquid, and the particle size distribution.

When the prediction of the solid content concentration in the clarified liquid is out of the certain range, the control device 5 operates the flow rate control valve 6 to change the supply flow rate as the operating condition. By changing the flow rate of the supply liquid, a correlation between the particle size and the partial collection efficiency, which is different from the correlation in FIG. 2, is obtained, and the solid content concentration in the clarified liquid is newly predicted. This operation is repeated so that the solid content concentration in the clarified liquid falls within a certain range.

The solid content concentration in the clarified liquid is measured online by the concentration measuring device 7. The solid content concentration of the clarified liquid predicted by the control device 5 is compared with the solid content concentration of the clarifier actually measured by the concentration measuring device 7.

The experimental results are shown in FIG. Fig. 5 during fining operation
When the particle size distribution of the solid content of the supply liquid is shifted to the smaller side as shown in Fig. 7, the solid content concentration of the clarified liquid is kept within a certain range by adjusting the supply flow rate as shown in Fig. 7. I was able to. In FIG. 6, in the conventional example, since the supply flow rate was not adjusted, the particle size distribution of the solid content in the supply liquid increased in accordance with the shift.

(Embodiment 4 of Operating Method) In this embodiment, when the particle size distribution of the solid content in the feed liquid fluctuates, the number of rotations of the bowl is adjusted accordingly to keep the solid content concentration of the clarified liquid within a certain range. It is an example that is stored.

Concentration of solid content concentration and particle size distribution in the supply liquid
The measurement is performed online with the particle size distribution measuring device 3. The supply liquid flow rate is measured online with the flow meter 4. As in Example 1, the controller 5 having the clarification model shown in FIG. 2 predicts the solid content concentration in the clarified liquid by using the feed liquid flow rate, the solid content concentration in the supply liquid, and the particle size distribution.

When the prediction of the solid content concentration in the clarified liquid is out of the certain range, the control device 5 operates the motor 2 to change the bowl rotation speed as an operating condition. By changing the number of rotations of the bowl, a correlation between the particle size and the partial collection efficiency different from the correlation in FIG. 2 is obtained, and the solid content concentration in the clarified liquid is newly predicted. This operation is repeated so that the solid content concentration in the clarified liquid falls within a certain range.

Next, the solid content concentration in the clarified liquid is measured online by the concentration measuring device 7. The solid content concentration of the clear liquid predicted by the control device 5 is compared with the solid content concentration of the clear liquid actually measured by the concentration measuring device 7.

According to this example, almost the same data as in Example 3 was obtained.

[0038]

According to the present invention, when the supply flow rate of the supply liquid, the solid content concentration, and the solid content particle size distribution of the centrifugal clarifier fluctuates, the flow rate of the supply liquid is adjusted by the control device or the bowl rotation speed is adjusted. The fluctuation of the conventional clarified liquid can be controlled within a certain range by adjusting.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of an operating system of a centrifugal clarifier according to the present invention.

FIG. 2 is a curve diagram showing the relationship between the particle size of solids in the supply liquid and the partial collection efficiency for explaining the operation of the present invention.

FIG. 3 is a characteristic diagram showing the concentration of the clarified liquid when the concentration of the solid component in the supply liquid is changed in order to explain the action and effect of the present invention by comparing the embodiment of the present invention and the conventional example.

FIG. 4 is a characteristic diagram showing the supply amount controlled by the control device when the concentration of the solid component in the supply liquid is changed in Examples 1 and 2 of the method of the present invention in comparison with the conventional example.

FIG. 5 is a curve diagram showing the particle size distribution of the solid content in the supply liquid in Examples 3 and 4 of the method of the present invention by comparing before and after the change.

FIG. 6 is a characteristic diagram showing a comparison between the conventional example of the concentration of the clarified liquid and the example of the present invention when the particle size distribution of the solid content in the supply liquid is changed, as in FIG.

FIG. 7 is a characteristic diagram showing the supply amount controlled by the control device when the particle size distribution of the solid content in the supply liquid is changed, as in FIG. 5, in comparison with the embodiment of the present invention.

[Explanation of symbols]

1 ... Centrifugal clarifier, 2 ... Motor, 3 ... Concentration / particle size distribution measuring device, 4 ... Flowmeter, 5 ... Control device, 6 ... Flow control valve, 7 ... Concentration measuring device, 8 ... Supply liquid line, 9 ... Clearing liquid line.

Claims (4)

[Claims] 1. A flow control valve, a concentration / particle size distribution measuring instrument, and a flow meter are provided in a supply line of a centrifugal clarifier.
A concentration measuring device is provided in the clarification liquid line of the centrifugal clarifier, a motor is connected to the bowl in the centrifugal clarifier via a rotation shaft, and a controller having a clarification model for inputting the rotation speed of the motor is provided. An operating system of a centrifugal clarifier, wherein a flow control valve, a concentration particle size distribution measuring instrument, a flowmeter and a signal cable for inputting measured values of the concentration measuring instrument are connected to a control device. 2. A feed liquid containing solids and the like is supplied to a bowl in the centrifugal clarifier through a feed line of the centrifugal clarifier, and centrifugally separated in the bowl to remove the solids and the like. In the operating method of the centrifugal clarifier, in which the clarified liquid flowing out is discharged from the clarified liquid line of the centrifugal clarifier, the feed liquid flow rate, the rotation speed of the motor for rotating the bowl, and the component concentrations of the feed liquid and the clarified liquid are measured online. Then, the method of operating the centrifugal clarifier is characterized in that the flow rate of the supply liquid is adjusted so that the concentration of solids and the like in the clarification liquid falls within a certain range. 3. The method of operating a centrifugal clarifier according to claim 2, wherein the rotation speed of a motor for rotating the bowl is used instead of the supply liquid flow rate. 4. The operation of the centrifugal clarifier according to claim 2, wherein the supply liquid flow rate or the motor rotation speed is controlled by a controller having a clarification model so that the fluctuation of the clarification liquid is within a predetermined range. Method.