Information processing device, index value calculation method, and index value calculation program

Abstract

To calculate an index value which shows a retention time of liquid in a dehydrator.SOLUTION: An information processing device (1) includes: a data acquisition unit (101) which acquires a first index value in a time series concerning properties and states of sludge supplied to a dehydrator (9) and a second index value in the time series which reflects a dehydration property of a dehydrated cake discharged after the sludge is dehydrated; and an index value calculation unit (103) which calculates a retention time of the sludge in the dehydrator (9) on the basis of a difference in a temporal axis direction between a time series variation in the first index value and a time series variation in the second index value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for estimating the residence time of a liquid containing suspended solids inside a dehydrator when the liquid is dehydrated using the dehydrator. [Background technology]

[0002] Sludge treatment carried out in wastewater treatment facilities such as sewage treatment plants includes a step of dewatering the sludge using a dehydrator. For efficient sludge treatment, it is important to maintain the moisture content of the dehydrated cake obtained by dehydration within a predetermined range. However, when dehydration treatment is performed under constant operating conditions of the dehydrator, the moisture content of the dehydrated cake fluctuates due to factors such as inconsistent properties of the supplied sludge, making it difficult to maintain the moisture content of the dehydrated cake within the predetermined range.

[0003] For this reason, development of technology for predicting the moisture content of dehydrated cake has been underway. If the moisture content can be predicted, it will be possible to maintain the moisture content within a predetermined range through feedforward control. For example, Patent Document 1 listed below discloses a technology for estimating the moisture content by generating a moisture content estimation model using multiple parameters, such as the amount of sludge supplied to a centrifugal dehydrator and values ​​related to the centrifugal effect of the dehydrator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-114569 Summary of the Invention [Problem to be solved by the invention]

[0005] When generating a moisture content estimation model like the one described above, training data is required that correlates various parameters (explanatory variables) related to the sludge supplied to the dehydrator and the operating conditions of various devices with the moisture content of the dehydrated cake (target variable), but there is a problem in that this correlation is not easy. This is because there is a time lag between the time when the sludge is supplied to the dehydrator (i.e., the time when the explanatory variables are determined) and the time when the supplied sludge is discharged as dehydrated cake (i.e., the time when the target variable is determined), and it is difficult to actually measure this time lag (i.e., the residence time of the sludge in the dehydrator). This problem is not limited to sludge, but is a common problem that occurs in the dehydration process of any liquid containing suspended solids.

[0006] An object of one aspect of the present invention is to provide an information processing device or the like capable of calculating an index value indicating the retention time of a liquid containing suspended solids in a dehydrator. [Means for solving the problem]

[0007] In order to solve the above problem, an information processing device according to one embodiment of the present invention includes a data acquisition unit that acquires a first time-series index value relating to the properties of a liquid containing suspended solids that is supplied to a dehydrator and a second time-series index value that reflects the dehydration of a dehydrated cake that is discharged after the liquid is dehydrated in the dehydrator, and an index value calculation unit that calculates a third index value that indicates the residence time of the liquid inside the dehydrator based on the shift in the time axis direction between the time-series change of the first index value and the time-series change of the second index value.

[0008] In addition, an index value calculation method according to one embodiment of the present invention is an index value calculation method executed by one or more information processing devices in order to solve the above-mentioned problems, and includes a data acquisition step of acquiring a first time-series index value related to the properties of a liquid containing suspended solids supplied to a dehydrator and a second time-series index value reflecting the dehydration of a dehydrated cake discharged after the liquid is dehydrated in the dehydrator, and an index value calculation step of calculating a third index value indicating the residence time of the liquid inside the dehydrator based on the shift in the time axis direction between the time-series change of the first index value and the time-series change of the second index value. [Effects of the Invention]

[0009] According to one aspect of the present invention, it is possible to calculate a third index value, which is an index value indicating the residence time that the liquid containing suspended solids has been retained in the dehydrator. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing an example of a main configuration of an information processing device according to an embodiment of the present invention; [Figure 2] FIG. 10 is a diagram illustrating an example of the configuration of a control system including the information processing device. [Figure 3] 10 is a diagram showing time-series measurement result data of the flow rate per unit time of the liquid supplied to the flocculator and time-series measurement result data of the opening degree of the back pressure plate. FIG. [Figure 4] 10A and 10B are diagrams illustrating an increase / decrease match number analysis and an increase / decrease match rate analysis. [Figure 5] FIG. 10 is a diagram showing time-series measurement result data of the flow rate per unit time of the liquid supplied to the flocculator and time-series measurement result data of the opening degree of the back pressure plate when the screw rotation speed is changed during dehydration processing. [Figure 6] 10 is a flowchart illustrating an example of processing executed by the information processing device. DETAILED DESCRIPTION OF THE INVENTION

[0011] [System Configuration] The configuration of a control system according to one embodiment of the present invention will be described with reference to FIG. 2. FIG. 2 is a diagram showing an example of the configuration of a control system 100. The control system 100 is a system used in a plant that adds an agent that coagulates suspended solids to a liquid to be treated in a coagulation tank to form flocs, and then performs solid-liquid separation of the liquid to be treated in which the flocs have formed. In the following, an example will be described in which the liquid to be treated is sludge, but the control system 100 can also be applied to plants that treat liquids other than sludge. Note that sludge is a liquid containing fine solids that is generated during wastewater treatment, etc., and can also be called slurry.

[0012] As will be explained in detail below, the control system 100 performs each process of the sludge treatment process, from the process of converting the sludge to be treated into flocculated sludge by flocculating solid suspended matter in the sludge to be treated to form flocs, to the process of dewatering the flocculated sludge to obtain dehydrated sludge (also called dehydrated cake) and dehydrated filtrate. As shown in Fig. 2, the control system 100 includes an information processing device 1, a control device 3, a flocculator 5, and a dehydrator 9.

[0013] The flocculator 5 is a device that adds a chemical agent that coagulates suspended solids to the liquid being treated in a coagulation tank and moderately stirs the liquid to form flocs. Specifically, the flocculator 5 uses sludge as the liquid being treated, coagulates suspended solids in the sludge to form flocs, and produces coagulated sludge. The flocculator 5 in FIG. 2 includes a coagulation tank 51, a stirring blade 52, a motor 53, and an inspection window 54. The flocculator 5 also includes a sludge inlet 55, a chemical agent inlet 56, and a discharge outlet 57.

[0014] Furthermore, a photographing device 72 and a lighting device 71 for photography are attached to the inspection window 54. The photographing device 72 may be any device capable of taking at least still images. It is preferable that the coagulation tank 51 is opaque so that the way light hits the flocs does not change while the control system 100 is in operation. Furthermore, it is preferable that the photographing device 72 and the lighting device 71 are housed in a light-blocking dark box with an opening on the inspection window 54 side, as in the illustrated example.

[0015] The dehydrator 9 is a device that performs solid-liquid separation of the liquid to be treated in which flocs have formed. Specifically, the dehydrator 9 is disposed downstream of the flocculator 5 and performs solid-liquid separation by dehydrating the flocculated sludge discharged from the flocculator 5. The dehydrator 9 in FIG. 2 is a screw press type dehydrator equipped with an outer screen 91 and a screw 92. The dehydrator 9 is also provided with a sludge inlet 93, a filtrate outlet 94, and a dehydrated cake outlet 95. Although not shown, the dehydrator 9 also includes a motor for rotating the screw 92. Of course, the dehydrator 9 is not limited to the screw press type as long as it can dehydrate the flocculated sludge. For example, a centrifugal dehydrator, a filter press dehydrator, or a belt press dehydrator may also be used.

[0016] In the control system 100, the sludge to be treated is continuously or intermittently supplied from a sludge inlet 55 into the coagulation tank 51 of the flocculator 5 by a supply device (not shown), and the sludge pushed out and discharged from the coagulation tank 51 is supplied to the dehydrator 9, so that the flow rate of the sludge supplied to the coagulation tank 51 and the flow rate of the sludge supplied to the dehydrator 9 coincide at the same time. The supply rate of the sludge may be automatically controlled by the supply device or its control device 3 according to the sludge treatment rate by the flocculator 5 and the dehydrator 9.

[0017] Then, chemicals (including at least a flocculant) for flocculating the sludge are fed into the sludge in the coagulation tank 51 through chemical inlet 56. In this state, motor 53 is driven to rotate agitator blade 52, which mixes the sludge and chemicals and forms flocs. The flocculated sludge, which is a mixture of the formed flocs and the water contained in the sludge, is discharged from outlet 57.

[0018] Subsequently, this flocculated sludge is supplied into the outer body screen 91 from the sludge inlet 93 of the dehydrator 9. In the dehydrator 9, the flocculated sludge is dehydrated under pressure by the screw 92, and the filtrate is discharged from the filtrate outlet 94, while the dehydrated cake, which is a mass of dehydrated flocculated sludge, is discharged from the dehydrated cake outlet 95.

[0019] As will be explained in detail below, the information processing device 1 acquires a first time-series index value relating to the properties of the liquid containing suspended solids that is supplied to the dehydrator 9, and a second time-series index value that reflects the dehydration of the dehydrated cake that is discharged after the liquid is dehydrated in the dehydrator 9. Then, the information processing device 1 calculates a third index value that indicates the retention time of the liquid inside the dehydrator 9, based on the shift in the time axis direction between the time-series changes of the first index value and the time-series changes of the second index value.

[0020] The first time-series index value relating to the properties of the liquid containing suspended solids is a value determined at the time the liquid is supplied to the dehydrator 9, while the second time-series index value reflecting the dehydration of the dehydrated cake is a value determined after or during dehydration. Since the dehydration of the dehydrated cake is affected by the properties of the liquid supplied to the dehydrator, the second index value changes in conjunction with the first index value, and the shift in the time axis direction of this change corresponds to the residence time of the liquid containing suspended solids in the dehydrator 9. Therefore, the information processing device 1 can calculate an index value indicating the residence time of the liquid containing suspended solids in the dehydrator 9.

[0021] The information processing device 1 can also control the operation of various devices (e.g., the flocculator 5, the dehydrator 9, and a chemical supply device (not shown)) that are components of the control system 100 via the control device 3. The control device 3 is a device that controls the operation of various devices that are components of the control system 100. The control device 3 may be, for example, a PLC (Programmable Logic Controller).

[0022] [Device configuration] The configuration of the information processing device 1 will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example of the configuration of the main parts of the information processing device 1. As shown in the figure, the information processing device 1 includes a control unit 10 that controls all parts of the information processing device 1, and a storage unit 11 that stores various data used by the information processing device 1. The information processing device 1 also includes a communication unit 12 that enables the information processing device 1 to communicate with other devices, an input unit 13 that accepts input of various data to the information processing device 1, and an output unit 14 that enables the information processing device 1 to output various data.

[0023] The control unit 10 also includes a data acquisition unit 101, a conversion unit 102, an index value calculation unit 103, a teacher data generation unit 104, and an equipment control unit 105. The conversion unit 102, the teacher data generation unit 104, and the equipment control unit 105 will be described below in the sections "Conversion," "Generation of Teacher Data," and "Control for Varying Index Values," respectively.

[0024] The data acquisition unit 101 acquires a first index value in a time series relating to the properties of the liquid containing suspended solids supplied to the dehydrator 9, and a second index value in a time series reflecting the dehydration of the dehydrated cake discharged after the liquid is dehydrated by the dehydrator 9. The first index value and the second index value will be explained later in the section "Regarding the first index value and the second index value."

[0025] The index value calculation unit 103 calculates a third index value indicating the retention time of the liquid inside the dehydrator 9 based on the shift in the time axis direction between the time series change of the first index value and the time series change of the second index value. A specific method for calculating the third index value will be described later in the section "Method for calculating the third index value."

[0026] As described above, the information processing device 1 according to this embodiment includes a data acquisition unit 101 that acquires a first time-series index value relating to the properties of the liquid containing suspended solids that is supplied to the dehydrator 9 and a second time-series index value that reflects the dehydration of the dehydrated cake that is discharged after the liquid is dehydrated in the dehydrator 9, and an index value calculation unit 103 that calculates a third index value that indicates the residence time of the liquid inside the dehydrator 9 based on the shift in the time axis direction between the time-series change of the first index value and the time-series change of the second index value. This makes it possible to calculate the third index value, which is an index value that indicates the residence time of the liquid containing suspended solids that is retained inside the dehydrator 9.

[0027] [Regarding the first and second index values] The first index value may be time-series data relating to the properties of the liquid containing suspended solids supplied to the dehydrator 9. For example, the flow rate per unit time of the liquid supplied to the dehydrator 9 may be used as the first index value. This is because, when the supply pressure of the liquid to the dehydrator 9 is controlled to be constant, the flow rate of the liquid supplied to the dehydrator 9 reflects the properties of the liquid. For example, if the dehydration property of the liquid is high, the supply flow rate to the dehydrator 9 will be high, and if the dehydration property of the liquid is low, the supply flow rate will be low. Furthermore, for example, the supply flow rate of the liquid to the flocculator 5 will be high if the dehydration property of the liquid is high and low if the dehydration property of the liquid is low. Therefore, the flow rate per unit time of the liquid supplied to the flocculator 5 may be used as the first index value.

[0028] Alternatively, the first index value may be a value that exhibits the same behavior as the flow rate per unit time of the liquid supplied to the dehydrator 9. For example, the first index value may be a value obtained by dividing the flow rate per unit time of the liquid supplied to the dehydrator 9 by the screw rotation speed of the dehydrator 9.

[0029] On the other hand, the second index value may be time-series data that reflects the dehydration of the dehydrated cake that is discharged after the liquid is dehydrated in the dehydrator 9. For example, the opening between the discharge section and a back pressure plate that applies back pressure in the discharge section of the dehydrator 9 (hereinafter referred to as the opening of the back pressure plate) may be used as the second index value. If the dehydration of the dehydrated cake is high, the opening of the back pressure plate will be low, and if the dehydration of the dehydrated cake is low, the opening of the back pressure plate will be high, so the opening of the back pressure plate is appropriate as the second index value.

[0030] In addition, the current value for driving the screw of the dehydrator 9 and the driving torque of the screw will be lower if the dehydration property of the dehydrated cake is low and will be higher if the dehydration property of the dehydrated cake is high, so these values ​​can also be used as second index values.

[0031] As a result of experiments conducted by the inventors of the present application, it has been confirmed that an appropriate third index value can be calculated by applying the flow rate per unit time of the liquid supplied to the dehydrator 9 as the first index value and the opening degree of the back pressure plate as the second index value. Therefore, an appropriate third index value can be calculated by applying the flow rate per unit time of the liquid supplied to the dehydrator 9 as the first index value and the opening degree of the back pressure plate as the second index value.

[0032] Of course, the flow rate per unit time of the liquid supplied to the dehydrator 9 is merely an example of the first index value, and the opening degree of the back pressure plate is merely an example of the second index value. The first index value may be time-series data relating to the properties of the liquid containing suspended solids supplied to the dehydrator 9, and the second index value may be time-series data reflecting the dehydration of the dehydrated cake discharged after the liquid is dehydrated in the dehydrator 9.

[0033] When the flow rate per unit time of the liquid supplied to the flocculator 5 is applied as the first index value, there is a slight time lag between the time when the liquid supplied to the flocculator 5 reaches the dehydrator 9. However, since this time lag is short compared to the residence time of the liquid in the dehydrator 9, there is no problem in applying the flow rate per unit time of the liquid supplied to the flocculator 5 as the first index value. Of course, the third index value may be calculated taking this time lag into consideration. For example, the index value calculation unit 103 may calculate, as the final third index value, a value obtained by subtracting a predetermined time corresponding to the time lag (residence time in the flocculator 5) from the third index value calculated by applying the flow rate per unit time of the liquid supplied to the flocculator 5 as the first index value.

[0034] [Calculation method for the third index value] (1) Cross-correlation analysis The index value calculation unit 103 may derive a first function that indicates the time series change of the first index value and a second function that indicates the time series change of the second index value, and calculate the third index value by performing cross-correlation analysis using the derived first function and second function.

[0035] In this case, when the derived first function is f(t) and the derived second function is g(t), the index value calculation unit 103 calculates τ that maximizes h(τ), which is expressed by the following cross-correlation function (CCF). Note that t is time. The τ calculated in this way indicates the shift in the time axis direction between the time series changes of the first index value and the time series changes of the second index value, and can be used as a third index value. This will be explained based on FIG. 3.

[0036]

number

[0037] 3 is a diagram showing time-series measurement result data of the flow rate per unit time of the liquid supplied to the dehydrator 9 and time-series measurement result data of the opening degree of the back pressure plate. Specifically, measurement result data D1 shows the time-series measurement results of the flow rate per unit time of the liquid supplied to the dehydrator 9, and measurement result data D2 shows the time-series measurement results of the opening degree of the back pressure plate. Furthermore, data D3 is data obtained by shifting measurement result data D2 by τ along the time axis.

[0038] The index value calculation unit 103 can derive a function f(t) that indicates a time series change in the flow rate per unit time of the liquid supplied to the dehydrator 9 from the measurement result data D1. Similarly, the index value calculation unit 103 can derive a function g(t) that indicates a time series change in the opening degree of the back pressure plate from the measurement result data D2. As shown in the figure, the peaks of the functions f(t) and g(t) appear similarly, but the peak of the function g(t) appears later than that of the function f(t).

[0039] This indicates that there is a time lag between when the flow rate per unit time of the liquid supplied to the dehydrator 9 changes and when that change appears in the opening degree of the back pressure plate. This time lag is approximately equal to the residence time of the liquid in the dehydrator 9.

[0040] This time difference can be rephrased as the deviation in the time axis direction between the time series change in the flow rate per unit time of the liquid supplied to the dehydrator 9, shown by the function f(t), and the time series change in the opening of the back pressure plate, shown by the function g(t). τ in the cross-correlation function can be said to indicate this deviation. Therefore, τ calculated using the cross-correlation function can be used as a third index value. As shown in the figure, the peak positions and shapes of the function f(t) and the function g(t+τ), obtained by shifting the function g(t) by τ along the time axis, are roughly the same.

[0041] (2) Analysis of the number of matches and the rate of matches Furthermore, the index value calculation unit 103 may calculate the third index value by an increase / decrease match number analysis or an increase / decrease match rate analysis. The increase / decrease match number analysis or the increase / decrease match rate analysis is performed to determine the amount of shift when the second index value in the time series is shifted along the time axis so as to maximize the number of matches in the increase / decrease patterns between the first index value and the second index value. The increase / decrease match rate analysis is performed to determine the amount of shift when the second index value in the time series is shifted along the time axis so as to maximize the match rate in the increase / decrease patterns between the first index value and the second index value.

[0042] The increase / decrease match number analysis and the increase / decrease match rate analysis will be described with reference to Fig. 4. Fig. 4 is a diagram for explaining the increase / decrease match number analysis and the increase / decrease match rate analysis.

[0043] The graph shown at the top of Fig. 4 shows time-series measurement result data D1 of the flow rate per unit time of the liquid supplied to the flocculator 5 and time-series measurement result data D2 of the opening degree of the back pressure plate. Note that the measurement result data D1 is a first index value in the time series, and the measurement result data D2 is a second index value in the time series. Fig. 4 also shows an enlarged view of the section from 125 minutes to 140 minutes in the measurement result data D1 and the measurement result data D2.

[0044] When performing an increase / decrease match number analysis, the index value calculation unit 103 classifies each of the first index values ​​constituting the measurement result data D1 into one of those that have increased from the previous value, those that have decreased, or those that have not changed. The index value calculation unit 103 also classifies the second index values ​​constituting the measurement result data D2 in the same way. In FIG. 4, an increase from the previous value is represented by "+", a decrease by "-", and an unchanged value by "0".

[0045] Next, the index value calculation unit 103 determines whether the classification results of the first index value and the second index value measured at the same time match. For example, as shown in the enlarged view of Figure 4, from 125 minutes to 134 minutes, both the measurement result data D1 and the measurement result data D2 increase monotonically, so the above determination result is "match." On the other hand, from 135 minutes onwards, the measurement result data D1 starts to decrease, while the measurement result data D2 continues to increase, so the above determination result is "mismatch."

[0046] Then, the index value calculation unit 103 calculates the number of increases / decreases in match or the increase / decrease match rate based on the above judgment results. The number of increases / decreases in match is the total number of times a match was judged, and the increase / decrease match rate is the number of times a match was judged to be a match divided by the total number of times a match was judged.

[0047] The index value calculation unit 103 repeats the above process while changing the amount of shift in the time axis direction of the measurement result data D2, and finds the amount of shift that maximizes the number of increase / decrease matches or the increase / decrease match rate.

[0048] The graph at the bottom of Figure 4 shows the measurement result data D1 and D2 described above, as well as data D3, which is obtained by shifting measurement result data D2 along the time axis to maximize the number of increases and decreases. As shown in the enlarged view of the section from 125 minutes to 140 minutes, the increase and decrease patterns of measurement result data D1 and data D3 are generally consistent. Note that data obtained by shifting measurement result data D2 along the time axis to maximize the increase and decrease agreement rate will usually be roughly similar to data D3.

[0049] As described above, the index value calculation unit 103 may calculate the third index value based on the shift amount τ when the second function g(t) is shifted in the time axis direction so that the correlation between the first function f(t) indicating the time series change of the first index value and the second function g(t) indicating the time series change of the second index value is maximized.

[0050] In addition, the index value calculation unit 103 may calculate the third index value based on the amount of shift when the second index value in the time series is shifted along the time axis so that the number of matches or the rate of matches between the first index value and the second index value in the pattern of increase or decrease from the previous value in chronological order is maximized.

[0051] As a result of experiments conducted by the inventors of the present application, it has been confirmed that an appropriate third index value can be calculated when any of the above methods is applied. Therefore, according to the above configuration, an appropriate third index value can be calculated.

[0052] (Exclusion of measurements from unstable periods) 3 and 4, the flow rate per unit time of the liquid supplied to the dehydrator 9 is unstable for the first 30 minutes or so. Therefore, the index value calculation unit 103 may calculate the third index value without using the measured value (first index value) during this period when the flow rate is unstable. This is the same when the above-mentioned cross-correlation analysis is applied, and also when the increase / decrease match number analysis or increase / decrease match rate analysis is applied.

[0053] (Combining multiple different methods) Furthermore, the index value calculation unit 103 may calculate the third index value using a plurality of different methods and calculate a final third index value based on the calculation results. For example, the index value calculation unit 103 may calculate the third index value using three methods: cross-correlation analysis, increase / decrease match number analysis, and increase / decrease match rate analysis. Furthermore, for each of the three methods, the index value calculation unit 103 may calculate the third index value for both a pattern that uses measured values ​​during the period when the flow rate is unstable and a pattern that does not use measured values. This allows six different third index values ​​to be calculated.

[0054] By calculating the final third index value based on these six different third index values, the index value calculation unit 103 can calculate a more stable third index value than when only one third index value is calculated using one method. For example, the index value calculation unit 103 may calculate, as the final third index value, the average of the remaining two third index values, excluding the largest and second largest, and the smallest and second smallest, of the six different third index values. Of course, this calculation method is just one example, and the index value calculation unit 103 may also calculate, for example, the average or median of multiple third index values ​​calculated using multiple methods as the final third index value.

[0055] [Conversion] If the dehydrator 9 is a screw press dehydrator, the screw rotation speed of the dehydrator 9 may change during the measurement period of the first index value and the second index value. As will be explained in detail below, the screw rotation speed is an operating condition that affects the residence time of sludge in the dehydrator 9, so if the screw rotation speed changes, it may become difficult to calculate an appropriate third index value. The conversion unit 102 is provided to deal with such problems.

[0056] Specifically, conversion unit 102 converts the measurement time of the first index value in the time series into the integrated value of the screw rotation speed of dehydrator 9 up to that measurement time. Similarly, conversion unit 102 converts the measurement time of the second index value in the time series into the integrated value of the screw rotation speed of dehydrator 9 up to that measurement time. Then, index value calculation unit 103 calculates a third index value using the value obtained by converting the measurement times of the first index value and the second index value into the integrated value of the screw rotation speed of dehydrator 9 up to that measurement time.

[0057] This allows the third index value to be calculated based on the time axis shift of the time-series change taking into account changes in the screw rotation speed, making it possible to calculate an appropriate third index value even when the screw rotation speed is changed.

[0058] Fig. 5 shows time-series measurement result data D1 of the flow rate per unit time of the liquid supplied to the dehydrator 9 and time-series measurement result data D2 of the opening degree of the back pressure plate when the screw rotation speed is changed during the dehydration process. Note that while the horizontal axis in the graphs shown in Fig. 3 and Fig. 4 is in units of time, the horizontal axis of the graph in Fig. 5 is the cumulative screw rotation speed.

[0059] In this example, as shown by the dashed-dotted line in Figure 5, the screw rotation speed is changed from 0.15 (rpm) to 0.20 (rpm) when the cumulative screw rotation speed reaches R. This change in the screw rotation speed (more precisely, the number of rotations per unit time) affects the time-series changes in both the flow rate per unit time of the liquid supplied to the dehydrator 9 and the opening of the back pressure plate, but there is a lag in the timing at which these effects appear. For this reason, if the horizontal axis of the graph representing the measurement result data D1 and D2 is expressed in units of time, moving the measurement result data D2 along the time axis will not match the pattern of the measurement result data D1, making it difficult to calculate a valid third index value.

[0060] In contrast, when the horizontal axis of the graph representing the measurement result data D1 and D2 is in units of the cumulative number of screw rotations, the peaks of the measurement result data D1 and data D3 obtained by shifting the measurement result data D2 by r along the time axis overlap and their patterns match, as shown in Figure 5. Therefore, r can be said to indicate the shift along the time axis between the time series changes in the first index value and the time series changes in the second index value, and the index value calculation unit 103 can calculate this r as the third index value.

[0061] Furthermore, the index value calculation unit 103 may convert the calculated r into time. For example, if r=3 when the screw rotation speed is 0.20 (revolutions / minute), the index value calculation unit 103 may set the third index value to 15 minutes. Even when conversion is performed, the third index value can be calculated in the same manner as when conversion is not performed.

[0062] [Generation of training data] The following describes a method for generating training data by training data generating unit 104. The training data generated by training data generating unit 104 is training data for generating a prediction model that predicts the moisture content of a dehydrated cake from index values ​​related to the properties of the liquid (liquid containing suspended solids) supplied to dehydrator 9.

[0063] The index value may be any value related to the moisture content of the dehydrated cake. For example, the index value may be at least any of data such as the flow rate per unit time of the liquid supplied to the dehydrator 9 or the concentration of suspended solids, data related to the chemical supplied to the flocculator 5 (such as the chemical supply flow rate and the ratio of the amount of chemical to the amount of liquid, i.e., the chemical dosing rate), data related to the liquid in the flocculator 5 (such as floc size or various index values ​​related thereto), data indicating the operating conditions of the flocculator 5 (such as the stirring speed), and data indicating the operating conditions of the dehydrator 9 (such as the screw rotation speed, operating time, and input pressure). The index value related to the liquid in the flocculator 5 may be obtained by analyzing an image captured by the image capture device 72 shown in FIG. 2, for example. The value used to calculate the third index value can be used for the flow rate per unit time of the liquid supplied to the dehydrator 9.

[0064] These index values ​​may be time-series data measured during the measurement period of the first index value and the second index value. In addition, even if an index value is measured after the measurement period of the first index value and the second index value, it can be used to generate training data as long as the dwell time when the index value was measured does not change significantly from the dwell time indicated by the third index value.

[0065] For example, suppose the properties of the liquid to be treated change from day to day and multiple dehydration processes are performed in one day. In this case, the first index value and the second index value may be measured during one of the multiple dehydration processes. The training data generation unit 104 may then generate training data using a third index value calculated from the measured first index value and second index value, and index values ​​measured during each dehydration process performed that day.

[0066] The training data generating unit 104 selects an index value to be associated with the measured moisture content of the dehydrated cake from the time series of index values ​​based on the residence time indicated by the third index value. For example, the training data generating unit 104 may associate the moisture content of the dehydrated cake discharged at a certain time with an index value measured at a time point that is the residence time indicated by the third index value before that time, and use this as training data.

[0067] For example, if the residence time indicated by the third index value is 45 minutes, training data generating unit 104 may associate the moisture content measured for the dehydrated cake discharged at 12:00 with the index value measured at 11:15, and use this as training data. Note that, when the moisture content is measured with a moisture meter, the measurement time is used as the moisture content and the discharge time of the dehydrated cake. When, for example, the user collects the dehydrated cake and measures it manually, the user may input the time the dehydrated cake was collected via input unit 13.

[0068] Furthermore, when the third index value indicates the screw rotation speed of the dehydrator 9, the teacher data generating unit 104 may calculate the residence time from the screw rotation speed indicated by the third index value and the screw rotation speed (number of rotations per unit time). Note that the process of calculating the residence time from the screw rotation speed may be performed by the index value calculating unit 103 or the converting unit 102.

[0069] As described above, the training data generation unit 104 associates the moisture content of the dehydrated cake discharged from the dehydrator 9 at a certain time with an index value related to the liquid properties measured at a time derived based on the residence time specified using the third index value and the certain time, and generates training data to be used in training a prediction model that predicts the moisture content of the dehydrated cake from the index value. This makes it possible to automatically generate training data to be used in training a prediction model that predicts the moisture content of the dehydrated cake.

[0070] The information processing device 1 may also include a learning unit that generates a prediction model for predicting the moisture content of the dehydrated cake or updates an already-generated prediction model using the training data generated as described above. This allows the generation or updating of a prediction model using newly measured index values ​​to be performed as frequently as necessary without requiring the user's effort, and also makes it possible to maintain high moisture content prediction accuracy.

[0071] As described above, the index value calculation unit 103 may calculate the third index value using a plurality of different methods. When the index value calculation unit 103 calculates the third index value using a plurality of different methods, the teacher data generation unit 104 may generate teacher data based on at least one of the third index values ​​calculated using the plurality of different methods if a difference between the third index values ​​calculated using the plurality of different methods is within a predetermined allowable range.

[0072] If the calculation method changes, the calculated third index value may also change. If the calculated multiple third index values ​​deviate from each other, there is a possibility that any or all of the third index values ​​may be invalid.

[0073] In this regard, as described above, if a configuration is adopted in which, when the difference between multiple third index values ​​calculated using multiple different methods is within a predetermined tolerance range, training data is generated based on at least one of the third index values, the possibility of generating inappropriate training data based on an inappropriate third index value can be reduced.

[0074] If the index value calculation unit 103 calculates the third index value using three or more methods, the teacher data generation unit 104 may select two of the third index values ​​and determine whether the difference between them is within a predetermined tolerance range. For example, the index value calculation unit 103 may calculate the third index value using six methods and calculate the average of two third index values ​​excluding the largest and second largest, and the smallest and second smallest, as the final third index value. In this case, the teacher data generation unit 104 may select two third index values ​​to be used in calculating the final third index value and determine whether the difference between them is within a predetermined tolerance range.

[0075] [Control to vary index value] Here, the device control unit 105 will be described. The device control unit 105 controls the operation of various devices that are components of the control system 100. As shown in FIG. 2, this control may be performed via the control device 3. Alternatively, the device control unit 105 may perform this control without the control device 3. As will be described below, the device control unit 105 may perform control to calculate an appropriate third index value.

[0076] Here, in order to accurately identify the time-axis offset between the time series change in the first index value and the time series change in the second index value, it is desirable that both of these time series changes be distinctive (for example, have bumps and dips when graphed as in the example of Figure 3, etc.). However, for example, if the properties of the liquid supplied to the dehydrator 9 are continuously stable, the time series change in the first index value will be small and the time series change in the second index value linked to this will also be small, making it difficult to identify the time offset between them.

[0077] Therefore, the equipment control unit 105 may vary the first index value and the second index value by performing a predetermined control on a predetermined equipment related to dehydration of a liquid containing suspended solids during the period in which the first index value and the second index value are measured.

[0078] This makes it easier to identify the time axis deviation between the time series changes in the first index value and the time series changes in the second index value, even if the properties of the liquid containing suspended solids being supplied remain stable, and makes it possible to calculate an appropriate third index value.

[0079] The predetermined device may be any device that can affect the time-series changes in the first index value and the second index value. For example, the device control unit 105 may control a drug supply device to the flocculator 5 to change the drug supply flow rate or drug injection rate during the measurement period of the first index value and the second index value. Also, for example, the device control unit 105 may control the flocculator 5 to change the stirring speed during that period.

[0080] [Processing flow] The flow of the process (index value calculation method) executed by the information processing device 1 will be described with reference to Fig. 6. Fig. 6 is a flowchart showing an example of the process executed by the information processing device 1. Note that before the process of Fig. 6 starts, a spin-drying process is performed by the spin-drying machine 9, and the first index value and the second index value are measured during the period in which the process is being performed. During this period, the device control unit 105 may vary the first index value and the second index value by performing predetermined control on a predetermined device related to the spin-drying of the liquid.

[0081] In S1 (data acquisition step), the data acquisition unit 101 acquires a first index value in time series relating to the properties of the liquid containing suspended solids that is supplied to the dehydrator 9, and a second index value in time series reflecting the dehydration of the dehydrated cake that is discharged after the liquid is dehydrated in the dehydrator 9. The method for acquiring the first index value is not particularly limited, and for example, the data acquisition unit 101 may acquire the first index value input by a user via the input unit 13, or may acquire the first index value from a device that measures the first index value via the communication unit 12. The same applies to the second index value.

[0082] In S2, conversion unit 102 converts the measurement times of the first index value and the second index value acquired in S1 into an integrated value of the screw rotation speed of dehydrator 9 up to the measurement time. Note that data such as the screw rotation speed required for the conversion may be input by the user via input unit 13, or may be acquired from control device 3 or the like via communication unit 12. Furthermore, if the screw rotation speed of dehydrator 9 has not changed during the measurement period of the first index value and the second index value, or if dehydrator 9 is not a screw press dehydrator, the processing of S2 is omitted.

[0083] In S3 (index value calculation step), the index value calculation unit 103 calculates a third index value indicating the retention time of the liquid inside the dehydrator 9 based on the difference in the time axis direction between the time series change of the first index value and the time series change of the second index value. As a method for calculating the third index value, various methods can be applied, as described in the section "Method for calculating the third index value."

[0084] In S4, the training data generation unit 104 uses the third index value calculated in S3 to generate training data to be used in training a prediction model that predicts the moisture content of the dehydrated cake, and the processing in Fig. 6 is then completed. The method for generating training data is as described in the section "Generation of Training Data." Note that the processing in S4 may be performed by a device other than the information processing device 1, in which case the processing in S4 is omitted.

[0085] As described above, the index value calculation method of this embodiment includes a data acquisition step (S1) of acquiring a first time-series index value related to the properties of the liquid containing suspended solids supplied to the dehydrator 9 and a second time-series index value reflecting the dehydration of the dehydrated cake discharged after the liquid is dehydrated in the dehydrator 9, and an index value calculation step (S3) of calculating a third index value indicating the residence time of the liquid inside the dehydrator 9 based on the shift in the time axis direction between the time-series change of the first index value and the time-series change of the second index value. Thus, the third index value, which is an index value indicating the residence time of the liquid containing suspended solids inside the dehydrator 9, can be calculated.

[0086] [Modification] The execution entity of each process described in the above embodiment is arbitrary and is not limited to the above example. For example, each step of the index value calculation method shown in Fig. 6 can be shared among multiple information processing devices. In other words, the index value calculation method may be executed by one information processing device 1 or may be executed by multiple information processing devices.

[0087] [Software implementation example] The functions of the information processing device 1 (hereinafter referred to as the "device") can be realized by a program for causing a computer to function as the device, and a program (index value calculation program) for causing a computer to function as each control block of the device (particularly each part included in the control unit 10).

[0088] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The control device and storage device execute the program, thereby realizing the functions described in each of the above embodiments.

[0089] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0090] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0091] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0092] 1. Information processing equipment 101 Data Acquisition Unit 103 Index value calculation unit 104 Teacher data generation unit 105 Equipment control section

Claims

1. a data acquisition unit that acquires a plurality of first index values ​​relating to the properties of a liquid containing suspended solids that is supplied to the dehydrator, the plurality of first index values ​​being measured over time, and a plurality of second index values ​​that reflect the dehydration of a dehydrated cake that is discharged after the liquid is dehydrated in the dehydrator, the plurality of second index values ​​being measured over time; an index value calculation unit that calculates a third index value indicating a retention time of the liquid inside the dehydrator based on a time axis shift between a pattern of change over time of the first index value and a similar pattern of change over time of the second index value, The index value calculation unit (1) A shift amount obtained by cross-correlation analysis using a first function that indicates a change over time in the first index value, derived from the plurality of first index values ​​measured over time, and a second function that indicates a change over time in the second index value, derived from the plurality of second index values ​​measured over time, when the second function is shifted in the time axis direction so as to maximize the correlation between the first function and the second function; and (2) An information processing device that calculates the third index value based on at least one of the amount of shift when the second index value in the time series is shifted along the time axis so that the number of matches or the rate of matches of the increase / decrease patterns from the previous value in chronological order for the first index value and the second index value are maximized.

2. the dehydrator is a screw press dehydrator, 2. The information processing device according to claim 1, wherein the index value calculation unit calculates the third index value using a value obtained by converting the measurement times of the first index value and the second index value into an integrated value of the screw rotation speed of the dehydrator up to the measurement time.

3. the first index value indicates a flow rate per unit time of the liquid supplied to the dehydrator, 3. The information processing apparatus according to claim 1, wherein the second index value indicates an opening degree between a back pressure plate that applies back pressure in a discharge section of the dehydrator and the discharge section.

4. 3. The information processing device according to claim 1, further comprising a training data generation unit that generates training data to be used in training a prediction model that predicts the moisture content of the dehydrated cake from the index value by associating the moisture content of the dehydrated cake discharged from the dehydrator at a certain time with an index value related to the properties of the liquid measured at a time derived based on the residence time identified using the third index value and the certain time.

5. the index value calculation unit calculates the third index value using a plurality of different methods; 5. The information processing device according to claim 4, wherein the teacher data generation unit generates the teacher data based on at least any of the third index values ​​calculated by a plurality of different methods when a difference between the third index values ​​is within a predetermined tolerance range.

6. 3. The information processing device according to claim 1, further comprising an equipment control unit that varies the first index value and the second index value by performing predetermined control on a predetermined device related to dehydration of the liquid during a period in which the first index value and the second index value are measured.

7. An index value calculation method executed by one or more information processing devices, a data acquisition step of acquiring a plurality of first index values ​​in a time series relating to the properties of a liquid containing suspended solids supplied to a dehydrator, the plurality of first index values ​​being measured over time, and a plurality of second index values ​​reflecting the dehydration of a dehydrated cake discharged after the liquid is dehydrated in the dehydrator, the plurality of second index values ​​being measured over time; an index value calculation step of calculating a third index value indicating a retention time of the liquid inside the dehydrator based on a time axis difference between a pattern of change over time of the first index value and a similar pattern of change over time of the second index value, In the index value calculation step, (1) A shift amount obtained by cross-correlation analysis using a first function that indicates a change over time in the first index value, derived from the plurality of first index values ​​measured over time, and a second function that indicates a change over time in the second index value, derived from the plurality of second index values ​​measured over time, when the second function is shifted in the time axis direction so as to maximize the correlation between the first function and the second function; and (2) An index value calculation method in which the third index value is calculated based on at least one of the amount of shift when the second index value in the time series is shifted along the time axis so that the number of matches or the rate of matches of the increase / decrease patterns from the previous value in chronological order for the first index value and the second index value are maximized.

8. 2. An index value calculation program for causing a computer to function as the information processing device according to claim 1, the index value calculation program causing the computer to function as the data acquisition unit and the index value calculation unit.

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