Plant control system, program and method

Abstract

The present invention provides a plant control device that enables actions to be taken at more appropriate times to improve monitoring items monitored in a plant. [Solution] The plant control device includes a control unit that controls monitoring items in the plant. The control unit acquires measured values ​​for the monitoring items, and based on the measured values, calculates a first required value which is the average of the measured values ​​from the current time to the second time, which is necessary to set the average of the measured values ​​from the first time in the past to the second time in the future as the first reference value, and performs a first action to improve the monitoring items according to the first required value.

Description

[Technical Field]

[0001] The present invention relates to a plant control device, program, and method. [Background technology]

[0002] Plants often have regulations in place regarding the emission of hazardous substances. Patent Document 1 discloses a waste incineration system in which, when the average concentration of hydrogen chloride in the exhaust gas exceeds a preset upper limit of the average value, the amount of treatment agent automatically fed into the dust collector is increased. The treatment agent includes an adsorbent that has the function of adsorbing dioxins in the exhaust gas. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 7264372 [Overview of the project] [Problems that the invention aims to solve]

[0004] To regulate the emission of hazardous substances, for example, the concentration of hazardous substances may be continuously monitored, and if the concentration exceeds a standard value, some action may be taken to reduce the concentration. In this case, the standard value may be set not for the instantaneous value, but for the time-averaged value (for example, the average value over the past hour). In this case, conventionally, corrective action has been taken simply when the time-averaged concentration exceeds the standard value.

[0005] However, the inventors realized that even if the time-averaged concentration reaches a reference value, depending on the recent pattern of concentration changes, there may or may not be cases where corrective action is necessary. For example, as shown in Figure 1A, if the instantaneous concentration is currently increasing, a further increase in the time-averaged concentration is expected in the future. Therefore, if nothing is done, there is a low possibility that the time-averaged concentration will return to a state below the reference value, so it is desirable to take corrective action. Conversely, for example, as shown in Figure 1B, if the instantaneous concentration is currently decreasing, a decrease in the time-averaged concentration is expected in the future, so there is no need to take immediate corrective action.

[0006] However, when simply comparing the time-averaged concentration with the reference value, as in the conventional method, the differences in the situations described above cannot be distinguished. As a result, corrective actions may be taken even when they are not actually necessary. Therefore, it is desirable to eliminate unnecessary actions and focus corrective actions only on more appropriate situations where they are truly needed. In the above explanation, the concentration of hazardous substances was used as an example for clarity, but similar problems apply to the control of various other monitoring items monitored in plants, such as temperature and noise levels.

[0007] The object of the present invention is to provide a plant control device, program, and method that enable actions to improve monitoring items monitored in a plant to be taken at a more appropriate time. [Means for solving the problem]

[0008] (Section 1) A plant control device for controlling monitoring items in a plant, The measured values ​​for the aforementioned monitoring items are obtained, Based on the measured values, the average value of the measured values ​​from the current time to the second time in the future is calculated as the first required value, which is necessary to set the average value of the measured values ​​from the first time in the past to the second time in the future as the first reference value. In response to the first request value, the first action to improve the monitoring item is performed. The control unit that executes the task A plant control device equipped with the following features.

[0009] (Section 2) The aforementioned first action includes: Warning issued, Controlling the control parameters of predetermined equipment related to the monitoring items in the plant, and To stop the predetermined equipment related to the monitoring items in the plant. Includes at least one of the following: The plant control device described in item 1.

[0010] (Section 3) The control unit determines to execute the first action based on the result of comparing the first requested value with at least one of the instantaneous value or average value of the measured value. A plant control device as described in item 1 or 2.

[0011] (Section 4) The control unit performs the first action according to the result of comparing the first requested value with at least one of the instantaneous value or average value of the predicted future value of the measured value. A plant control device as described in any of items 1 to 3.

[0012] (Section 5) The control unit calculates the probability that the instantaneous or average value of the measured value will exceed the first required value in the future, based on the measured value, and executes the first action according to the probability. A plant control device as described in any of items 1 to 4.

[0013] (Section 6) The aforementioned monitoring items are the concentration, temperature, or noise level of a specified substance. A plant control device as described in any of items 1 to 5.

[0014] (Section 7) The control unit is configured to based on the measured values, calculate, as a second required value, the average value of the measured values from the current time to the fourth time in the future, which is necessary to set the average value of the measured values from the third time in the past to the fourth time in the future as a second reference value, execute a second action for improving the monitoring item in accordance with the second required value, wherein the second reference value indicates a state where the monitoring item is more deteriorated than the first reference value, The plant control device according to any one of Items 1 to 6.

[0015] (Item 8) The second action includes issuing an alarm, controlling a control parameter of predetermined equipment related to the monitoring item in the plant, and stopping the predetermined equipment related to the monitoring item in the plant at least one of the foregoing. The plant control device according to Item 7.

[0016] (Item 9) A plant control program for controlling a monitoring item in a plant, the program causing a computer to execute acquiring a measured value measured for the monitoring item, based on the measured value, calculating, as a first required value, the average value of the measured values from the current time to a second time in the future, which is necessary to set the average value of the measured values from a first time in the past to the second time in the future as a first reference value, executing a first action for improving the monitoring item in accordance with the first required value .

[0017] (Item 10) A plant control method for controlling a monitoring item in a plant, the method using a computer to acquire a measured value measured for the monitoring item, ​Based on the measured values, the average value of the measured values ​​from the current time to the second time in the future is calculated as the first required value, which is necessary to set the average value of the measured values ​​from the first time in the past to the second time in the future as the first reference value. In response to the first request value, the first action to improve the monitoring item is performed. A plant control method that includes the following. [Effects of the Invention]

[0018] According to the present invention, a plant control device, program, and method are provided that enable actions to improve monitoring items monitored in a plant to be carried out at a more appropriate time. [Brief explanation of the drawing]

[0019] [Figure 1A] An example of a graph showing the instantaneous and time-averaged values ​​of concentration when the instantaneous concentration value is on an increasing trend. [Figure 1B] An example of a graph showing the instantaneous and time-averaged values ​​of concentration when the instantaneous concentration value is decreasing. [Figure 2] A block diagram showing the configuration of a plant controlled by a plant control device according to the first embodiment. [Figure 3] A block diagram showing the configuration of the plant control device according to the first embodiment. [Figure 4] An example of a concentration graph illustrating the reference values ​​according to the first embodiment. [Figure 5] A flowchart showing the flow of monitoring based on the first reference value according to the first embodiment. [Figure 6] A flowchart showing the flow of monitoring based on the second reference value according to the first embodiment. [Figure 7] An example of a concentration graph illustrating the required values ​​according to the first embodiment. [Figure 8A] An example of a concentration change in which the required value according to the first embodiment becomes lower than the current value. [Figure 8B] An example of a concentration change in which the required value according to the first embodiment is greater than or equal to the current value. [Figure 9] A flowchart showing the flow of the monitoring process according to the second embodiment. [Figure 10A] An example of a concentration change in which the required value according to the second embodiment is lower than the average value of future predictions. [Figure 10B] An example of a concentration change in which the required value according to the second embodiment is equal to or greater than the average value of future predicted values. [Figure 11] A flowchart showing the flow of the monitoring process according to the third embodiment. [Figure 12] A flowchart showing the flow of the monitoring process according to the fourth embodiment. [Figure 13A] An example of a concentration change according to the fourth embodiment in which the required value is greater than or equal to the current value and less than the maximum value of the future prediction. [Figure 13B] An example of a concentration change according to the fourth embodiment in which the required value is greater than or equal to the current value and greater than or equal to the maximum value of the future prediction. [Figure 14] A flowchart showing the flow of the monitoring process according to the fifth embodiment. [Figure 15] An example of the probability distribution of the difference between each measurement according to the fifth embodiment and the average value of the measurements over the following X minutes. [Figure 16] An example of a concentration graph for illustrating the excess probability according to the fifth embodiment. [Figure 17] A flowchart showing the flow of the monitoring process according to the sixth embodiment. [Figure 18] An example of the probability distribution of the difference between each measurement value according to the sixth embodiment and the maximum value of the measurement values ​​over the following X minutes. [Figure 19] An example of a concentration graph for illustrating the excess probability according to the sixth embodiment. [Modes for carrying out the invention]

[0020] Hereinafter, several embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated. Furthermore, each drawing is schematic, with parts omitted or exaggerated as appropriate, for ease of understanding.

[0021] [1. First Embodiment] [1-1. Overall Plant Configuration] Figure 2 shows the configuration of the plant 100 controlled by the plant control device 1 according to the first embodiment. The plant control device 1 performs overall control of the plant 100 and monitors and controls predetermined monitoring items in the plant 100. Although not limited to this, the plant 100 according to the first embodiment is a waste incineration facility, and the reference numeral 100 is also used for waste incineration facilities. In the following description, examples of monitoring items monitored and controlled by the plant control device 1 include the concentrations of predetermined hazardous substances (e.g., nitrogen oxides NOx, sulfur oxides SOx, hydrogen chloride HCl, etc.) in the exhaust gas discharged from the waste incineration facility 100.

[0022] The waste incineration facility 100 comprises a waste pit 2 and an incinerator 3. The waste pit 2 is a facility for temporarily storing waste (garbage). The incinerator 3 is, for example, a stoker type and incinerates the waste fed in from the waste pit 2. The waste incineration facility 100 further comprises a flue 4 and a boiler 41, dust collector 42, wet scrubbing tower 43, denitrification reaction tower 44, induced draft fan 45, and chimney 46, which are connected to each other by the flue 4. The flue 4 is a passage through which exhaust gas discharged from the incinerator 3 flows, and in the example in Figure 2, it extends from the incinerator 3 to the chimney 46. In Figure 2, the flue 4 is indicated by a double-lined arrow. The boiler 41, dust collector 42, wet scrubbing tower 43, denitrification reaction tower 44, induced draft fan 45, and chimney 46 are arranged in this order from the upstream side to the downstream side of the exhaust gas flow.

[0023] The boiler 41 uses the thermal energy of the exhaust gas discharged from the incinerator 3 to evaporate the feedwater. The boiler 41 is connected to a steam turbine (not shown) that converts the thermal energy of the steam generated in the boiler 41 into mechanical energy to generate electricity.

[0024] The dust collector 42 is, for example, a bag filter that filters and collects fly ash from the exhaust gas using a filter (filter cloth). Upstream of the dust collector 42, a powdered chemical agent for removing harmful substances from the exhaust gas may be added to the exhaust gas, and this chemical agent may be collected in the dust collector 42 along with the fly ash. The chemical agent used here may include, for example, an agent for removing sulfur oxides and hydrogen chloride, and more specifically, an alkaline chemical agent such as slaked lime. In this case, in the dust collector 42, acidic gases such as sulfur oxides and hydrogen chloride in the exhaust gas are neutralized in a dry reaction with the alkaline chemical agent and rendered harmless. The chemical agent used here may also include an agent for removing dioxins, mercury compounds, etc.

[0025] The wet-type fume scrub tower 43 removes harmful substances from the exhaust gas by spraying water containing chemicals into the exhaust gas. The chemicals used here are, for example, chemicals for removing sulfur oxides and hydrogen chloride, and to give a more specific example, alkaline chemicals such as caustic soda. In this case as well, acidic gases such as sulfur oxides and hydrogen chloride in the exhaust gas react with the alkaline chemicals to neutralize them and render them harmless.

[0026] The denitrification reaction tower 44 has a denitrification catalyst inside and removes nitrogen oxides from harmful substances contained in the exhaust gas by adding an agent to the exhaust gas. The agent used here is, for example, a reducing agent such as ammonia. In this case, nitrogen oxides react with the reducing agent and are decomposed into nitrogen and water, rendering them harmless. The exhaust gas may be reheated in the denitrification reaction tower 44 as appropriate.

[0027] The induced draft fan 45 forms an airflow along the flue 4 from the incinerator 3 to the chimney 46. The exhaust gas that has passed through the induced draft fan 45 is introduced into the chimney 46, and after passing through the chimney 46, it is discharged to the outside.

[0028] The chimney 46 is equipped with multiple sensors 47 for measuring the concentration (monitoring items) of harmful substances in the exhaust gas discharged from the chimney 46. Each of these sensors 47 measures the concentration of, for example, nitrogen oxides NOx, sulfur oxides SOx, hydrogen chloride HCl, etc. Measurements by the sensors 47 may be performed continuously at short time intervals (e.g., 1 second), or intermittently at somewhat longer time intervals (e.g., 1 minute). The measured values ​​from the sensors 47 are transmitted in real time from the sensors 47 to the plant control device 1 and stored as time-series data in the storage unit 12, which will be described later.

[0029] [1-2. Plant Control System Configuration] Figure 3 shows the configuration of the plant control device 1 according to this embodiment. The plant control device 1 is implemented, for example, by a general-purpose computer. The plant control device 1 comprises a control unit 11, a storage unit 12, a display unit 13, an input unit 14, and a communication interface 15. Each of the units 11 to 15 is electrically connected to each other via a bus, cable, or the like.

[0030] The control unit 11 includes a CPU (Central Processing Unit) 112, RAM (Random Access Memory) 114, and ROM (Read Only Memory) 116. The storage unit 12 is composed of an auxiliary storage device such as a hard disk drive or a solid-state drive. The storage unit 12 stores a plant control program 121 that causes the plant control device 1 to perform various processes. The control unit 11 loads the plant control program 121 into RAM, and the CPU interprets and executes it, thereby performing various processes including the operations of the plant control device 1 described later.

[0031] The display unit 13 is a display that shows various screens to users such as operators. The display unit 13 is composed of a monitor such as an LCD monitor or an OLED (Electro-Luminescence) monitor. The input unit 14 receives input from users such as operators. The input unit 14 is composed of a mouse, keyboard, touch panel, microphone, etc.

[0032] The communication interface 15 is a device that enables communication connections with external devices. The communication interface 15 is composed of communication modules such as a wired LAN (Local Area Network) module or a wireless LAN module. The plant control device 1 is connected to various equipment included in the waste incineration facility 100 (for example, the incinerator 3, boiler 41, dust collector 42, wet scrubbing tower 43, denitrification reaction tower 44, induced draft fan 45, sensor 47, etc.) via the communication interface 15. As a result, the control unit 11 can acquire information from the various equipment and control the operation of the various equipment. For example, the control unit 11 acquires measured values ​​of the concentration of hazardous substances from the sensor 47. The control unit 11 can also control control parameters such as the supply amount of chemicals for removing hazardous substances from exhaust gas. Furthermore, the control unit 11 can start and stop the incineration process in the incinerator 3.

[0033] Some or all of the hardware that implements the plant control device 1 may be located within the plant 100, in a remote location, on the cloud, or distributed across these locations. For example, the functions of the control unit 11 and the storage unit 12 may reside on the cloud, while the functions of the display unit 13 and the input unit 14, which serve as the user interface, may be located within the plant 100.

[0034] [1-3. Monitoring Process] The monitoring process performed by the plant control device 1 is described below. In the monitoring process, the concentration of hazardous substances (monitoring item) in the exhaust gas emitted from the waste incineration facility 100 is constantly monitored, and when there is a high possibility that the concentration of hazardous substances will exceed the standard value (the monitoring item will worsen below the standard value), an action to reduce the concentration of hazardous substances (improve the monitoring item) is automatically executed. The concentration referred to here is not the instantaneous value of the concentration, but the time-averaged value of the concentration (for example, the average value over one hour). Accordingly, the standard value referred to here is also set based on the time-averaged value, not the instantaneous value. Hereafter, unless otherwise specified, when simply referring to the average value, it means the time-averaged value.

[0035] In this embodiment, two types of reference values ​​are used. Figure 4 is an example of a graph showing the concentration of hazardous substances to illustrate the reference values. In this embodiment, as shown in Figure 4, a self-imposed limit value (an example of a second limit value) r2 and a monitoring limit value (an example of a first limit value) r1, which is stricter than the self-imposed limit value r2, are set as reference values. The self-imposed limit value r2 indicates a state where the concentration of hazardous substances is higher than the monitoring limit value r1 (the monitoring items have worsened). If the concentration of hazardous substances exceeds the self-imposed limit value r2 (the monitoring items worsen beyond the self-imposed limit value r2), it may become necessary to severely restrict the operation of the waste incineration facility 100 (for example, to stop the operation of the incinerator 3) in order to improve such a situation. Therefore, in order to prevent such a situation from occurring, in this embodiment, multi-stage monitoring based on multiple reference values ​​is implemented. That is, in order to strengthen monitoring, a monitoring limit value r1 that is stricter than the self-imposed limit value r2 is set, and monitoring is first performed based on the monitoring limit value r1, and then monitoring is performed based on the self-imposed limit value r2. Furthermore, if legal limits are established for the concentration of hazardous substances (monitoring items), it is preferable that the voluntary limit r2 be stricter (lower) than the legal limit.

[0036] In this embodiment, in addition to the monitoring process described above, control is also performed to bring the instantaneous value of the concentration closer to the control target value SV, rather than the average value of the concentration. For example, if the instantaneous value of the concentration exceeds the control target value SV (if the monitored item deteriorates below the control target value SV), the supply of the agent to remove the harmful substance is increased, and the concentration is lowered (the monitored item is improved). As a result, when the instantaneous value of the concentration improves to below the control target value SV, the supply of the agent to remove the harmful substance is reduced. It is preferable that the control target value SV is stricter than the reference value (in terms of the concentration of harmful substances, it is lower). Furthermore, if the reference value is set at multiple levels, it is preferable that the control target value SV is even stricter than the stricter reference value among those reference values ​​(in the above example, the monitoring reference value r1). This is because if the instantaneous value is maintained near the control target value SV, which is stricter than the reference value, it is less likely that the average value will reach the reference value.

[0037] FIG. 5 shows the flow of monitoring processing based on the monitoring reference value (first regulation value) r1 according to the first embodiment, and FIG. 6 shows the flow of monitoring processing based on the self-imposed regulation value (second regulation value) r2 according to the first embodiment. Hereinafter, these monitoring processes will be described in order.

[0038] [1-3-1. Monitoring Processing Based on Monitoring Reference Value] The monitoring processing based on the monitoring reference value r1 in FIG. 5 is repeatedly executed at a predetermined time interval (preferably equal to or longer than the measurement interval by the sensor 47) during the operation of the incinerator 3. First, the control unit 11 acquires the measured value measured for the monitoring item, that is, the measured value of the concentration of the harmful substance in the exhaust gas discharged from the waste incineration facility 100 (step S1). As described above, the concentration of the harmful substance is measured every moment by the sensor 47, and stored as time-series data in the storage unit 12. The control unit 11 refers to the storage unit 12 and reads the time-series data of the measured values for the latest predetermined period.

[0039] Subsequently, the control unit 11 calculates the first required value s1 based on the time-series data of the measured values for the latest predetermined period acquired in step S1 and the monitoring reference value r1 (step S2). FIG. 7 is an example of a concentration graph for explaining the first required value s1. The first required value s1 is the average value of the measured values from the current time to the second time, which is required to set the average value of the measured values from the past first time to the future second time as the monitoring reference value (first regulation value) r1. More specifically, the period for evaluating the average value is n minutes, the first time is m minutes before the current time, and the second time is (n-m) minutes after the current time. Note that m can be arbitrarily set within a range satisfying m<n, for example, n minutes can be 60 minutes, and m minutes can be 50 minutes. In this case, let the average value of the measured values for m minutes from the first time to the current time be C 0,m , and let the average value of the measured values for (n-m) minutes from the current time to the second time be C n-m,n-m , then the average value C of the measured values for n minutes from the first time to the second time n-m,n is as follows. [Mathematical Formula]

[0040] Therefore, the average value C of the measurements from the first time point to the second time point. n-m,n The average value C of the measurements taken from the current time to the second time point is necessary to set the monitoring reference value r1. n-m,n-m The first requirement value s1 is as follows:

number

[0041] The values ​​of n and m, and the monitoring reference value r1 are pre-set and stored in the memory unit 12. 0,m This is calculated by averaging the most recent m minutes of measurements included in the time-series data of the measurements obtained in step S1. The control unit 11 calculates the first required value s1 by substituting these values ​​into equation 2.

[0042] Next, the control unit 11 performs a first action to improve the concentration of hazardous substances (monitoring item) according to the first requirement value s1 calculated in step S2 (step S3). Specifically, the control unit 11 compares the first requirement value s1 with the current value (instantaneous value) of the measured value and determines the content of the subsequent action according to the comparison result. If the first requirement value s1 < current value (see Figure 8A), the control unit 11 performs the first action because there is a high possibility that the concentration of hazardous substances will exceed the monitoring standard value r1 in the future. On the other hand, if the first requirement value s1 ≥ current value (see Figure 8B), there is a low possibility that the concentration of hazardous substances will immediately exceed the monitoring standard value r1 in the future, so nothing is done.

[0043] The first action includes, for example, at least one of (1) issuing an alarm and (2) controlling a predetermined equipment control parameter related to a monitoring item in plant 100. For (1), for example, the control unit 11 may create an alarm screen and display it on the display unit 13 for a user such as an operator. Alternatively, for example, the control unit 11 may provide an audible alarm instead of or in addition to displaying an alarm screen. For (2), for example, the control unit 11 may change the supply amount of the chemical agent used to remove hazardous substances from the exhaust gas to an increased amount. Alternatively, for example, the control unit 11 may set the control target value SV described above to a stricter value (a lower value in terms of hazardous substance concentration). The supply amount of the chemical agent and the control target value SV are equipment control parameters related to the concentration of hazardous substances. After receiving an alarm in (1), a user such as an operator can then operate the input unit 14 to manually perform some action, for example, the action in (2), in order to improve the concentration of hazardous substances. In this sense, the issuance of the alarm in (1) can be said to be an action to improve the concentration of hazardous substances. After step S3, the monitoring process in Figure 5 is completed.

[0044] [1-3-2. Monitoring process based on self-imposed limits] The monitoring process based on the self-imposed limit value r2 in Figure 6 is executed, for example, after the first action in the monitoring process in Figure 5 has been performed. Alternatively, the monitoring process in Figure 6 may be executed in parallel with the monitoring process in Figure 5 while the incinerator 3 is in operation.

[0045] First, the control unit 11 obtains the measured value for the monitored item, namely the measured value of the concentration of the harmful substance (step S11). Step S11 is performed in the same manner as step S1.

[0046] Subsequently, the control unit 11 calculates a second required value s2 based on the time-series data of the measured values for the most recent predetermined period acquired in step S11 (step S12). The second required value s2 is the average value of the measured values from the current time to the fourth time, which is necessary to set the average value of the measured values from the past third time to the future fourth time as the self-regulatory value (second reference value) r2. The second required value s2 is calculated in the same manner as the first required value s1 by replacing the first time and the second time with the third time and the fourth time respectively, and replacing the monitoring reference value r1 with the self-regulatory value r2 (see Figure 7). That is, the average value C of the measured values from the third time to the fourth time n-m,n The average value C of the measured values from the current time to the fourth time, which is necessary to set the self-regulatory value r2 n-m,n-m The second required value s2 is as follows. Note that the values of n and m when calculating the second required value s2 may be the same as or different from the values when calculating the first required value s1. [Equation]

[0047] The values of n and m and the self-regulatory value r2 are set in advance and stored in the storage unit 12. C 0,m is calculated from the time-series data of the measured values acquired in step S11, similarly to step S2. The control unit 11 calculates the second required value s2 by substituting these values into the equation of Equation 3.

[0048] Subsequently, the control unit 11 executes a second action for improving the concentration of the harmful substance (monitoring item) in accordance with the second required value s2 calculated in step S12 (step S13). Specifically, the control unit 11 compares the second required value s2 with the current value (instantaneous value) of the measured value, and determines the content of the subsequent action in accordance with the comparison result. When the second required value s2 < the current value (see Figure 8A), the control unit 11 executes the second action because there is a high possibility that the concentration of the harmful substance will exceed the self-regulatory value r2 in the future. On the other hand, when the second required value s2 ≥ the current value (see Figure 8B), there is a low possibility that the concentration of the harmful substance will immediately exceed the self-regulatory value r2 in the future, and thus no action is taken.

[0049] The second action includes, for example, at least one of (1) issuing an alarm, (2) controlling the control parameters of a predetermined piece of equipment related to the monitoring item in plant 100, and (3) stopping a predetermined piece of equipment related to the monitoring item in plant 100. For (1), for example, the control unit 11 may display an alarm screen and / or issue an audible alarm, similar to step S3. The alarm screen and / or audible alarm in the second action is preferably a stronger warning than that in the first action. For (2), for example, the control unit 11 may change the supply amount of the agent for removing harmful substances in the exhaust gas to be higher than that in the first action. Alternatively or in addition, for example, the control unit 11 may set the control target value SV described above to a stricter value (lower in terms of harmful substance concentration) than that in the first action. For (3), for example, the control unit 11 may stop the operation of the incinerator 3. The incinerator 3 is equipment related to the concentration of harmful substances. After step S13, the monitoring process in Figure 6 is completed.

[0050] [2. Second Embodiment] Next, the monitoring process according to the second embodiment will be described with reference to Figure 9. The configuration of the plant 100 and the plant control device 1 is the same as in the first embodiment. The monitoring process shown in Figure 9 is repeatedly performed at predetermined time intervals (preferably the same as or longer than the measurement interval by the sensor 47) while the incinerator 3 is in operation.

[0051] First, the control unit 11 acquires the measured value for the monitored item, i.e., the measured value of the concentration of the hazardous substance (step S21). Next, the control unit 11 calculates the first required value s1 based on the measured value acquired in step S21 (step S22). Steps S21 and S22 are performed in the same manner as steps S1 and S2, respectively.

[0052] Next, the control unit 11 performs a first action to improve the concentration of hazardous substances (monitoring item) according to the first requirement value s1 calculated in step S22 (step S23). Specifically, the control unit 11 compares the first requirement value s1 with the average value of future predicted values ​​of measured values ​​for the next Y minutes, and determines the content of subsequent actions according to the comparison result. The value of Y can be set as appropriate, but preferably, Y = nm, similar to the period for evaluating the first requirement value s1.

[0053] Future predicted values ​​can be calculated using various methods with historical data, for example, using a model constructed from historical data. Examples of such models include autoregressive models (AR, MA, ARMA, ARIMA, SARIMA, ARIMAX, etc.), state-space models, and machine learning models (RNN, LSTM, etc.). The historical data referred to here may include not only measured values ​​of the target monitoring item (concentration of hazardous substances), but also measured values ​​of other monitoring items, and / or set values ​​of control parameters of predetermined equipment related to the monitoring item. For example, future predicted values ​​of nitrogen oxide concentration in exhaust gas can be calculated using measured values ​​or target values ​​(control parameters) of the amount of air used for combustion in the incinerator 3.

[0054] If the first required value s1 < the average value of future predicted values ​​(see Figure 10A), the control unit 11 executes the first action because there is a high probability that the concentration of hazardous substances will exceed the monitoring standard value r1 in the future. On the other hand, if the first required value s1 ≥ the average value of future predicted values ​​(see Figure 10B), there is a low probability that the concentration of hazardous substances will immediately exceed the monitoring standard value r1 in the future, so the control unit may do nothing or perform a mitigation action. A mitigation action is an action that relaxes the level of restriction on the monitored item.

[0055] The first action can be performed in the same manner as in the first embodiment. Alternatively, as the first action, in lieu of or in addition to (1) and (2) above, (3) stopping a predetermined piece of equipment (e.g., incinerator 3) related to the monitoring item in plant 100 may be performed.

[0056] A mitigation action is an action that acts in a direction that increases the concentration of hazardous substances (worsens the monitoring item). The conditions under which a mitigation action is performed (first requirement value s1 ≥ average value of future predictions) are met when there is sufficient margin before the concentration of hazardous substances (monitoring item) reaches the monitoring standard value r1. Therefore, under such circumstances, a process (mitigation action) may be performed to mitigate the action to maintain / improve the monitoring item. For example, a mitigation action may include controlling the control parameters of predetermined equipment related to the monitoring item in plant 100. For example, the control unit 11 may change to reduce the supply amount of chemicals for removing hazardous substances in the exhaust gas. Alternatively or in addition to this, for example, the control unit 11 may set the above-mentioned control target value SV to a mitigated (higher in terms of hazardous substance concentration) value. After step S33, the monitoring process in Figure 9 is completed.

[0057] [3. Third Embodiment] Next, the monitoring process according to the third embodiment will be described with reference to Figure 11. The configuration of the plant 100 and the plant control device 1 is the same as in the first embodiment. The monitoring process shown in Figure 11 is repeatedly performed at predetermined time intervals (preferably the same as or longer than the measurement interval by the sensor 47) while the incinerator 3 is in operation.

[0058] First, the control unit 11 acquires the measured value for the monitored item, that is, the measured value of the concentration of the harmful substance (step S31). Next, the control unit 11 calculates the first required value s1 based on the measured value acquired in step S31 (step S32). Steps S31 and S32 are performed in the same manner as steps S1 and S2, respectively.

[0059] Next, the control unit 11 performs a first action to improve the concentration of hazardous substances (monitoring item) according to the first request value s1 calculated in step S32 (step S33). Specifically, the control unit 11 compares the first request value s1 with the current value (instantaneous value) of the measured value, and also compares the first request value s1 with the average value of the predicted future measured values ​​for the next Y minutes, and determines the content of the subsequent action according to the results of these comparisons. The predicted future values ​​and their average value can be calculated in the same way as in step S23 of the second embodiment.

[0060] If the first required value s1 < current value, the control unit 11 executes the first action because there is a high probability that the concentration of hazardous substances will exceed the monitoring standard value r1 in the future. Also, even if the first required value s1 ≥ current value, if the first required value s1 < the average value of future predicted values, the control unit 11 executes the first action because there is a high probability that the concentration of hazardous substances will exceed the monitoring standard value r1 in the future. On the other hand, if the first required value s1 ≥ current value AND the first required value s1 ≥ the average value of future predicted values, there is a low probability that the concentration of hazardous substances will immediately exceed the monitoring standard value r1 in the future, so the control unit 11 may do nothing or perform a mitigation action.

[0061] The first action and mitigation operation can be performed in the same manner as in the second embodiment. After step S33, the monitoring process shown in Figure 11 is terminated.

[0062] [4. Fourth Embodiment] Next, the monitoring process according to the fourth embodiment will be described with reference to Figure 12. The configuration of the plant 100 and the plant control device 1 is the same as in the first embodiment. The monitoring process shown in Figure 12 is repeatedly performed at predetermined time intervals (preferably the same as or longer than the measurement interval by the sensor 47) while the incinerator 3 is in operation.

[0063] First, the control unit 11 acquires the measured value for the monitoring item, that is, the measured value of the concentration of the harmful substance (step S41). Next, the control unit 11 calculates the first required value s1 based on the measured value acquired in step S41 (step S42). Steps S41 and S42 are performed in the same manner as steps S1 and S2, respectively.

[0064] Next, the control unit 11 performs a first action to improve the concentration of harmful substances (monitoring item) according to the first requirement value s1 calculated in step S42 (step S43). Specifically, the control unit 11 compares the first requirement value s1 with the current value (instantaneous value) of the measured value, and also compares the first requirement value s1 with the maximum value (instantaneous value) of the predicted future measured value for the next Y minutes, and determines the content of the subsequent action according to the results of these comparisons. The predicted future value can be calculated in the same way as in step S23 of the second embodiment. The value of Y can be set as appropriate, but preferably, Y = nm, similar to the period for evaluating the first requirement value s1.

[0065] If the first required value s1 < current value, the control unit 11 executes the first action because there is a high probability that the concentration of hazardous substances will exceed the monitoring standard value r1 in the future. If the first required value s1 ≥ current value and the first required value s1 < maximum future predicted value (see Figure 13A), the control unit does nothing because there is a low probability that the concentration of hazardous substances will immediately exceed the monitoring standard value r1 in the future. If the first required value s1 ≥ current value and the first required value s1 ≥ maximum future predicted value (see Figure 13B), the control unit 11 executes a mitigation action because there is currently sufficient margin before the concentration of hazardous substances (monitoring item) exceeds the monitoring standard value r1.

[0066] The first action and mitigation operation can be performed in the same manner as in the second embodiment. After step S43, the monitoring process shown in Figure 12 is terminated.

[0067] [5. Fifth Embodiment] Next, the monitoring process according to the fifth embodiment will be described with reference to Figure 14. The configuration of the plant 100 and the plant control device 1 is the same as in the first embodiment. The monitoring process shown in Figure 14 is repeatedly performed at predetermined time intervals (preferably the same as or longer than the measurement interval by the sensor 47) while the incinerator 3 is in operation.

[0068] In the fifth embodiment, the control unit 11 calculates the probability p1 of exceeding the first required value s1, which is the average value of the measured values ​​over the next X minutes, based on the accumulated data of past measured values ​​for the monitored item, and executes the first action according to the probability p1 of exceeding the value. The accumulated data of measured values ​​is time-series data of a large number of measured values ​​collected over a long period of time in the past (e.g., one month, one year, etc.) and is stored in the storage unit 12. For each measured value included in the accumulated data read from the storage unit 12, the control unit 11 calculates the difference d1 between the measured value and the average value of the measured values ​​over the X minutes since the measured value was measured. The value of X can be set as appropriate, but preferably, it can be set to X=nm, similar to the period for evaluating the first required value s1. Furthermore, the calculation of the difference d1 does not need to be performed for all measured values ​​included in the accumulated data; for example, it may be performed for some measured values ​​picked up at predetermined intervals. In any case, a large amount of difference d1 data is collected by the above calculation. The control unit 11 creates a histogram of the data for the difference d1 and generates a probability distribution (probability density function) for the difference d1. Figure 15 shows an example of a graph of the probability distribution of the difference d1. Although not always the case, typically the probability distribution of the difference d1 can be bell-shaped with a peak around 0.

[0069] Referring again to Figure 14, first, the control unit 11 acquires the measured value for the monitoring item, i.e., the measured value of the concentration of the hazardous substance (step S51). Subsequently, the control unit 11 calculates the first required value s1 based on the measured value acquired in step S51 (step S52). Steps S51 and S52 are performed in the same manner as steps S1 and S2, respectively.

[0070] Next, the control unit 11 obtains the probability distribution of the difference d1 (step S53). For example, if the probability distribution of the difference d1 has been calculated in advance and stored in the storage unit 12, it is read from the storage unit 12. Alternatively, the probability distribution of the difference d1 may be calculated in step S53.

[0071] Next, the control unit 11 calculates the excess probability p1, which is the probability that the average value of the measurements over the next X minutes will exceed the first required value s1, based on the probability distribution of the difference d1 obtained in step S53 and the first required value s1 calculated in step S52 (step S54). Figure 16 is an example of a graph of the concentration of harmful substances to illustrate the excess probability p1. The control unit 11 adds the current value of the measurement to the value on the horizontal axis of the probability distribution of the difference d1, and shifts the probability distribution of the difference d1 in the positive direction by the amount of the current value. In this case, for example, if the original probability distribution of the difference d1 was a bell shape with a peak around 0, the probability distribution of the difference d1 after the shift will be a bell shape with a peak around the current value. The shape of the graph of the probability distribution of the difference d1 does not change before and after the shift. The control unit 11 calculates the integral value (area) of the interval in the graph of the probability distribution of the difference d1 after translation that exceeds the first required value s1, as the excess probability p1.

[0072] Next, the control unit 11 performs a first action to improve the concentration of hazardous substances (monitoring item) according to the excess probability p1 calculated in step S54 (step S55). Specifically, the control unit 11 compares the excess probability p1 with a predetermined threshold and determines the content of the subsequent action according to the comparison result. If the excess probability p1 ≥ the threshold, the control unit 11 performs the first action because there is a high possibility that the concentration of hazardous substances will exceed the monitoring standard value r1 in the future. On the other hand, if the excess probability p1 < the threshold, there is a low possibility that the concentration of hazardous substances will immediately exceed the monitoring standard value r1 in the future, so the control unit 11 may do nothing or perform a mitigation action.

[0073] The first action and mitigation action can be performed in the same manner as in the second embodiment. After step S55, the monitoring process shown in Figure 14 ends.

[0074] [6. Sixth Embodiment] Next, the monitoring process according to the sixth embodiment will be described with reference to Figure 17. The configuration of the plant 100 and the plant control device 1 is the same as in the first embodiment. The monitoring process shown in Figure 17 is repeatedly performed at predetermined time intervals (preferably the same as or longer than the measurement interval by the sensor 47) while the incinerator 3 is in operation.

[0075] In the sixth embodiment, the control unit 11 calculates the probability p2 of exceeding the first required value s1 over the next X minutes, based on the accumulated data of past measured values ​​for the monitored item, and executes the first action according to the probability p2 of exceeding the first required value s1. The accumulated data of measured values ​​is the same as the data in the fifth embodiment. For each measured value included in the accumulated data read from the storage unit 12, the control unit 11 calculates the difference d2 between the measured value and the maximum measured value over the X minutes since the measured value was taken. The value of X can be set as appropriate, but preferably, it can be set to X=nm, similar to the period for evaluating the first required value s1. Furthermore, the calculation of the difference d2 does not need to be performed for all measured values ​​included in the accumulated data; for example, it may be performed for some measured values ​​picked up at predetermined intervals. In any case, a large amount of difference d2 data is collected by the above calculation. The control unit 11 creates a histogram of this difference d2 data and creates a probability distribution (probability density function) of the difference d2. Figure 18 is an example of a graph of the probability distribution of the difference d2.

[0076] Referring again to Figure 17, first, the control unit 11 acquires the measured value for the monitoring item, i.e., the measured value of the concentration of the hazardous substance (step S61). Subsequently, the control unit 11 calculates the first required value s1 based on the measured value acquired in step S61 (step S62). Steps S61 and S62 are performed in the same manner as steps S1 and S2, respectively.

[0077] Next, the control unit 11 obtains the probability distribution of the difference d2 (step S63). For example, if the probability distribution of the difference d2 has been calculated in advance and stored in the storage unit 12, it is read from the storage unit 12. Alternatively, the probability distribution of the difference d2 may be calculated in step S63.

[0078] Next, the control unit 11 calculates the excess probability p2, which is the probability that the maximum value of the measured values ​​over the next X minutes will exceed the first required value s1, based on the probability distribution of the difference d2 obtained in step S63 and the first required value s1 calculated in step S62 (step S64). Figure 19 is an example of a graph of the concentration of harmful substances to explain the excess probability p2. The control unit 11 adds the current value of the measured values ​​to the horizontal axis value of the probability distribution of the difference d2, and shifts the probability distribution of the difference d2 in the positive direction by the amount of the current value. The control unit 11 calculates the excess probability p2 as the integral value (area) of the interval in the graph of the probability distribution of the difference d2 after the shift that exceeds the first required value s1.

[0079] Next, the control unit 11 performs a first action to improve the concentration of hazardous substances (monitoring item) according to the excess probability p2 calculated in step S64 (step S65). Specifically, the control unit 11 compares the excess probability p2 with a predetermined threshold and determines the content of the subsequent action according to the comparison result. If the excess probability p2 ≥ threshold, the control unit 11 performs the first action because there is a high possibility that the concentration of hazardous substances will exceed the monitoring standard value r1 in the future. On the other hand, if the excess probability p2 < threshold, there is a low possibility that the concentration of hazardous substances will immediately exceed the monitoring standard value r1 in the future, so the control unit 11 may do nothing or perform a mitigation action.

[0080] The first action and mitigation operation can be performed in the same manner as in the second embodiment. After step S65, the monitoring process shown in Figure 17 is terminated.

[0081] [7. Features] In the first to sixth embodiments, the content of subsequent actions to control the monitoring items is determined according to the required values ​​s1 and s2 calculated as described above. The required values ​​s1 and s2 are the average values ​​of measurements from the current time to a future time, which are necessary to set the average of measurements from a past time to a future time as reference values ​​r1 and r2. Therefore, the required values ​​s1 and s2 are the values ​​that future measurements should take in order to prevent the average value of measurements from reaching the reference values ​​r1 and r2 in the future, and are new reference values ​​determined after considering the fluctuation trend of recent measurements. By executing subsequent actions according to such required values ​​s1 and s2, actions to improve the monitoring items monitored at plant 100 can be carried out at a more appropriate time when they are truly needed.

[0082] [8. Other Embodiments] Although several embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible without departing from its spirit. For example, the following modifications are possible. Furthermore, the gist of the following modifications can be combined as appropriate.

[0083] [8-1] The monitoring items are not limited to the concentration of hazardous substances; they may be the concentration of any substance, the temperature of any object, or the noise level of any space. For example, in order to reduce the concentration of dioxins, it may be desirable to maintain the incineration temperature in the incinerator 3 above a certain temperature (e.g., 850°C). In such cases, the reference value may be set to a higher temperature (e.g., 870°C), and the same monitoring process as in the above embodiment may be performed. Also, for example, the noise level may be desired to be kept below a certain value out of consideration for people inside and outside the plant 100. In such cases, the reference value may be set to a lower value, and the same monitoring process as in the above embodiment may be performed.

[0084] [8-2] In step S43 of the fourth embodiment, the first action may be performed if the first required value s1 < the maximum value of the future prediction.

[0085] [8-3] In steps S3 and S13 of the first embodiment, step S33 of the third embodiment, and step S43 of the fourth embodiment, the requested value was compared with the current value of the measured value (the most recent instantaneous value). However, the requested value may be compared with another most recent instantaneous value, such as the maximum or median of the measured values ​​over a predetermined period (e.g., 10 seconds), and subsequent actions may be performed according to the result of that comparison. Alternatively, the requested value may be compared with the average value of the measured values ​​over a predetermined period (e.g., 10 seconds), and subsequent actions may be performed according to the result of that comparison. It should be noted that comparing with the average value of the measured value is particularly useful when the time fluctuation of the instantaneous value of the measured value is large. Furthermore, if the time fluctuation of the instantaneous value of the measured value is large, the first / second action may be performed on the condition that the time during which the instantaneous value is higher than the requested value continues for a predetermined period.

[0086] [8-4] In step S43 of the fourth embodiment, the requested value was compared with the maximum value (instantaneous value) of the future predicted values ​​of the measured values ​​for the next Y minutes. However, the requested value may be compared with another instantaneous value, such as the median of the future predicted values ​​for the next Y minutes, and subsequent actions may be performed according to the result of that comparison.

[0087] [8-5] In step S65 of the sixth embodiment, the exceedance probability p2 of the maximum value (instantaneous value) of the measured values ​​over the next X minutes exceeding the first required value s1 was compared with a threshold. However, the exceedance probability p2 of another instantaneous value, such as the median of the measured values ​​over the next X minutes, exceeding the first required value s1 may be compared with the threshold, and subsequent actions may be performed according to the result of that comparison.

[0088] [8-6] In steps S3, S13, S23, S33, S43, S55, and S65 of the first to sixth embodiments, various comparisons can be appropriately combined, not limited to the embodiments described above, and subsequent actions can be determined according to the results of these comparisons. For example, in steps S3, S13, S33, and S43, the requested value may be compared with both the instantaneous value (current value, etc.) and the average value of the measured value. Alternatively, in steps S23, S33, and S43, the requested value may be compared with both the instantaneous value (maximum value, etc.) and the average value of the future predicted value. Alternatively, in steps S3, S13, S23, S33, S43, S55, and S65, in addition to the comparisons described above, at least one of the reference values ​​r1 and r2 may be compared with the average value of the current measured value, and subsequent actions may be performed according to the combination of these comparison results.

[0089] [8-7] In steps S55 and S65 of the fifth and sixth embodiments, the magnitudes of the excess probabilities p1 and p2 were classified in two stages, but they may also be classified in three or more stages. For example, if the excess probabilities p1 and p2 are 95% or higher, the control target value SV for the concentration of harmful substances may be lowered by 10 ppm; if the excess probabilities p1 and p2 are 80% or higher but less than 95%, the control target value SV may be lowered by 5 ppm; ... and if the excess probabilities p1 and p2 are less than 10%, the control target value SV may be raised by 10 ppm.

[0090] [8-8] The monitoring process according to the first embodiment is a two-stage control as shown in Figures 5 and 6, but one of the processes may be omitted. That is, a one-stage monitoring process may be performed based on only one of the monitoring standard value r1 or the self-regulation value r2. If the process in Figure 6 is omitted, in step S3 of the process in Figure 5, as in step S13, the first action may be to stop a predetermined piece of equipment (e.g., incinerator 3) related to the monitoring item in plant 100, instead of or in addition to (1) and (2) described above.

[0091] Conversely, although the monitoring process according to the second to sixth embodiments is a one-stage control based on the monitoring reference value r1, it may also be a two-stage control based on the monitoring reference value r1 and the self-regulation value r2, similar to the first embodiment. In this case, it is preferable that action (3) is not performed as the first action of the first stage of processing. Alternatively, the monitoring process according to the second to sixth embodiments may be a one-stage control based on the self-regulation value r2 instead of the monitoring reference value r1.

[0092] In the above explanation, in the second stage of processing, the second requirement value s2 is compared with the current value (instantaneous value) of the measured value, and the content of the subsequent action is determined according to the result of this comparison. However, when the two-stage processing is performed, the second requirement value s2 may be compared with various instantaneous or average values ​​of the measured value, or various instantaneous or average values ​​of future predicted values ​​of the measured value, similar to the example given for the first requirement value s1. Also, for the second requirement value s2, the same exceedance probabilities p1 and p2 as given for the first requirement value s1 may be calculated, and the content of the subsequent action may be determined according to the result of comparing these with the threshold.

[0093] Furthermore, control may be implemented in three or more stages based on three or more reference values. Also, the reference values ​​are not limited to the examples of monitoring reference value r1 and self-regulation value r2. [Explanation of Symbols]

[0094] 1. Plant control system 11 Control Unit 12 Storage section 13 Display section 14 Input section 15 Communication I / F 100 Plants (waste treatment facilities) 121 Plant Control Program 2 Waste pit 3 Incinerator 4 Flue 41 Boiler 42 Dust collector 43 Wet smoke washing tower 44 Denitrification Reactor 45 Induced Driving Ventilation Fan 46 Chimney 47 Sensors

Claims

1. A plant control device for controlling monitoring items in a plant, The measured values ​​for the aforementioned monitoring items are obtained, Based on the measured values, the average value of the measured values ​​from the current time to the second time is calculated as the first required value, which is necessary to set the average value of the measured values ​​from the first time in the past to the second time in the future as the first reference value. In accordance with the first request value, the first action to improve the monitoring item is performed. The control unit that executes the task A plant control device equipped with the following features.

2. The first action mentioned above includes: Warning issued, Controlling the control parameters of predetermined equipment related to the monitoring items in the plant, and To stop the predetermined equipment related to the monitoring items in the plant. Includes at least one of the following: The plant control device according to claim 1.

3. The control unit determines to execute the first action based on the result of comparing the first requested value with at least one of the instantaneous value or average value of the measured value. The plant control device according to claim 1 or 2.

4. The control unit performs the first action according to the result of comparing the first requested value with at least one of the instantaneous value or average value of the predicted future value of the measured value. The plant control device according to claim 1 or 2.

5. The control unit calculates the probability that the instantaneous or average value of the measured value will exceed the first required value in the future, based on the measured value, and executes the first action according to the probability. The plant control device according to claim 1 or 2.

6. The aforementioned monitoring items are the concentration, temperature, or noise level of a specified substance. The plant control device according to claim 1 or 2.

7. The control unit, Based on the aforementioned measurements, the average value of the aforementioned measurements from the present time to the fourth time is calculated as the second required value, which is necessary to set the average value of the aforementioned measurements from the third time in the past to the fourth time in the future as the second reference value. In accordance with the second requirement, a second action is performed to improve the monitoring item. The second reference value indicates a state in which the monitored item has worsened compared to the first reference value. The plant control device according to claim 1 or 2.

8. The second action described above includes: Warning issued, Controlling the control parameters of predetermined equipment related to the monitoring items in the plant, and To stop the predetermined equipment related to the monitoring items in the plant. Includes at least one of the following: The plant control device according to claim 7.

9. A plant control program that controls monitoring items in a plant, The measured values ​​for the aforementioned monitoring items are obtained, Based on the measured values, the average value of the measured values ​​from the current time to the second time is calculated as the first required value, which is necessary to set the average value of the measured values ​​from the first time in the past to the second time in the future as the first reference value. In accordance with the first request value, the first action to improve the monitoring item is performed. A plant control program that instructs a computer to perform certain actions.

10. A plant control method for controlling monitoring items in a plant, Using a computer, The measured values ​​for the aforementioned monitoring items are obtained, Based on the measured values, the average value of the measured values ​​from the current time to the second time is calculated as the first required value, which is necessary to set the average value of the measured values ​​from the first time in the past to the second time in the future as the first reference value. In accordance with the first request value, the first action to improve the monitoring item is performed. A plant control method that includes the following.

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