JP2022076571A - System control device and control method - Google Patents

Abstract

To provide a system control device capable of reducing the influence of the time constant of a controlled object to improve the responsiveness, suppressing the time fluctuation of an output, and increasing control speed, without the use of expensive controllers that require additional measuring equipment or complex computational algorithms.SOLUTION: The system control device of the present invention is a system control device that adjusts an operation amount to adjust a control amount for a controlled object that outputs a predetermined control amount by inputting a predetermined operation amount. In the system control device that performs feedback control of the controlled object so that the control amount output from the controlled object follows a control target value, the system control device includes a first adjustment unit that outputs a first operation amount based on a difference between the control target value and the control amount output from the controlled object, and a second adjustment unit that further raises signal gain for a signal that compares a physical quantity that is detected at an inlet of the controlled object and can predict the control amount with the first operation amount.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control target that outputs a predetermined control amount by inputting a predetermined operation amount, a system control device and a control method that adjusts the operation amount to adjust the control amount, and particularly, the control amount is timed. Regarding the technology to follow the target value without delay.

FIG. 5 shows, as an example of the system handled by the present invention, waste heat generated by using the incinerator 510 for burning waste and the exhaust heat of the combustion exhaust gas generated in the incinerator 510, which have been conventionally used. The schematic diagram of the waste incineration treatment facility 5 equipped with the boiler 520 is shown.

Since the size and composition of the waste carried into the waste incinerator 5 is not constant, it is stirred and mixed in a waste pit (not shown) before being put into the incinerator 510, and after being homogenized to some extent, it is shown in the figure. It is charged into the incinerator 510 by a charging device that does not. The waste introduced into the incinerator 510 is incinerated by the combustion air supplied from the primary combustion air supply device 511a and the secondary combustion air supply device 511b while slowly moving in the incinerator 510 by a feeding device (not shown). To. As the waste is incinerated in the incinerator 510, high-temperature combustion exhaust gas is generated. Although detailed description of individual elements will be omitted, the waste incineration facility 5 also includes an exhaust gas cooling device 530, a bag filter 540, an exhaust gas stack 550, an attracting ventilator 560, a chimney 570, and a control device 580. It is composed of a drug supply device 590 and the like.

The high-temperature combustion exhaust gas generated in the incinerator 510 is supplied to the waste heat boiler 520 via the exhaust gas stack 550. In the waste heat boiler 520, boiler water supply is circulated in a large number of water pipes, and the water in the water pipes is heated by the exhaust heat of the combustion exhaust gas to generate steam. The generated steam drives a steam turbine (not shown) and is mainly used for power generation.

It is very important to suppress the fluctuation of the amount of steam generated from the waste heat boiler 520 and keep it at a predetermined target value for stable operation of the waste incineration treatment facility. Therefore, conventionally, the amount of steam generated by the waste heat boiler 520 is measured by using the steam amount measuring means 521, and the incinerator 510 is used so that the measured amount of steam follows a preset control target value. Feedback control is performed to control combustion.

That is, as described above, since the composition of combustible components (C, H, S, etc.) is not constant in the waste put into the incinerator 510, the combustion generated even if the waste is stirred and mixed in the waste pit. The temperature and amount of exhaust gas may fluctuate. Therefore, by adjusting the supply amount of combustion air, the frequency of putting garbage into the incinerator 510, or the feeding speed of garbage in the incinerator 510, the amount of steam generated from the waste heat boiler 520 becomes a predetermined value. A control device 580 for controlling is provided. FIG. 6 shows a block diagram of the control performed by such a conventional simple feedback control device 580.

In FIG. 6, in the control system performed by the conventional simple feedback control device 580, the incinerator calculation unit 5F that calculates the input / output relationship of the incinerator 510 and the waste heat that calculates the input / output relationship of the waste heat boiler 520. It is composed of a boiler calculation unit 5B, an adjustment unit 5C, a comparison unit 581, and an addition unit 582. Here, R (s) is the input, that is, the Laplace transform of the control target value of the steam amount set by a setting device (not shown), and C (s) is the output, that is, the amount of steam generated from the waste heat boiler 520. Laplace transform, G _c (s) is the transfer function from input to output in the control unit C, G _f (s) is the transfer function from input to output in the incinerator 510, and G _b (s) is waste heat. The transfer function from input to output in the boiler 420, D (s) indicates the Laplace transform of the disturbance. The disturbance referred to here means fluctuations in the calorific value of waste and the like, and affects the amount of steam generated from the waste heat boiler 520.

The output C (s) of this feedback control system is expressed by the equation (1) using the input R (s) and the disturbance D (s). In the equation (1), (s) of the Laplace variable representation in each transfer function is omitted altogether (hereinafter, (s) in the equation is omitted).

From the equation (1), the transfer function G _f (s) of the incinerator 510 and the transfer function G _b (s) of the waste heat boiler 520 are assigned to both the input R (s) and the disturbance D (s) terms in the denominator. It can be seen that the product G _f (s) G _b (s) of is present. Here, G _f (s) and G _b (s) are expressed as equations (2) and (3), respectively.

Here, in the formulas (2) and (3), T _f and K _f represent the time constant and gain of the incinerator 510, respectively, and T _b and K _b represent the time constant and gain of the waste heat boiler 520, respectively. .. By the way, with respect to the time constant T _f of the incinerator 510, the time constant T _b of the waste heat boiler 520 becomes several times or more larger due to the large amount of heat possessed by the waste heat boiler 520. Specifically, T _f is within a few minutes, while T _b is 10 minutes or more. Therefore, the fluctuation of the generated steam amount due to the fluctuation of the calorific value of the combustion exhaust gas and the like appears considerably later than the fluctuation of the combustion exhaust gas. Therefore, if control is performed after detecting the fluctuation of the amount of steam, a time delay occurs in the output and a time fluctuation accompanied by vibration occurs. Conventionally, in order to follow such fluctuations in the amount of generated steam, PID (Proportional-Integral-Differential) control is performed in the adjusting unit C, and the time delay is compensated mainly by a differential operation (Differential Action: D operation). Designed for control. Alternatively, the properties of the garbage thrown into the garbage pit are predicted using AI (Artificial Integrity), and the feed rate of the garbage is adjusted so that combustion exhaust gas having a desired amount of heat is generated from the predicted properties of the garbage. ing. However, there is a limit to such PID control, and predictive control using AI requires an expensive control device for using a complicated calculation algorithm.

Further, as shown in Patent Document 1, the disturbance compensation unit is separated into a first arithmetic unit whose input is the operation amount output to the plant and a second arithmetic unit whose input is the control amount of the plant. A technique has been proposed in which the output of one arithmetic unit is fed back to the manipulated variable output and the output of the second arithmetic unit is incorporated into the preceding control unit of the feedback controller (Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-148489

According to the technique disclosed in Patent Document 1, since the output of the second arithmetic unit is incorporated in the preceding control unit of the feedback controller, it is possible to form a control system having good responsiveness even when the time constant of the controlled object is large. .. However, there is a problem that a plurality of arithmetic units are required and the device becomes complicated, and there is a problem that the response tends to vibrate and it takes time to converge just by incorporating the preceding control system.

Such a problem caused by a large time constant can occur not only in the combustion control of the incinerator 510 but also in other systems as well.

In the conventional waste incineration facility 5 shown in FIG. 5, the bag filter 540 is used to remove harmful acid gases such as soot and hydrogen chloride and sulfur oxides contained in the combustion exhaust gas. When removing acid gas such as hydrogen chloride and sulfur oxide, a neutralizing agent such as slaked lime is supplied to the inlet side of the bag filter 540 using a chemical supply device 590, and the neutralized salt is prepared. Collect with the bug filter 540. Then, the acid gas concentration is detected at the outlet of the bag filter 540 using the acid gas concentration detecting means 551, and the amount of the neutralizing agent supplied from the drug supply device 590 is adjusted based on the detection result.

Here, since the bug filter 540 itself has a large time constant, a time delay occurs between the concentration detection by the acid gas concentration detecting means 551 and the addition of the neutralizing agent, and the simple feedback control device as described above occurs. In 580, it is difficult to make the neutralizing agent supply amount follow the change in the acid gas concentration.

The present invention has been made in view of such problems, and reduces the influence of the time constant of the controlled object without using an expensive control device that requires additional measuring equipment or a complicated calculation algorithm. It is an object of the present invention to provide a system control device capable of improving responsiveness and suppressing time fluctuation of output.

The present invention provides the following solutions.

The invention according to the first feature is a control target that outputs a predetermined control amount by inputting a predetermined operation amount, and a system control device that adjusts the operation amount to adjust the control amount. In a system control device that performs feedback control of the control target so that the control amount output from is followed by the control target value, the first operation amount is output based on the difference between the control target value and the control amount output from the control target. Provided is a system control device provided with a first control unit for controlling a signal, and a second control unit for further increasing the signal gain for a signal in which a physical quantity detected at a controlled inlet and a predictable control amount is compared with the first manipulated quantity. do.

According to the invention according to the first feature, since the physical quantity detected at the control target inlet and the control amount can be predicted functions as a preceding element of the control amount output from the control target, the time constant of the control target is large. Even if there is, it is possible to perform control that suppresses the time delay. In addition, since the signal gain is further increased for the signal obtained by comparing the physical quantity detected at the control target inlet and the control amount can be predicted with the first manipulated variable, not only the effect of suppressing the time delay but also the amplitude of the response is performed. It is possible to obtain the effect of suppressing the control speed and increasing the control speed at the same time.

The invention according to the second feature is an invention according to the first feature, which is a waste heat boiler that generates steam by utilizing the exhaust heat of combustion exhaust gas generated in an incinerator as a control target, and waste heat as a controlled amount. The amount of steam generated from the boiler, the amount of combustion air supplied to the incinerator as the operating amount, and / or the amount of cooling water supplied are used, and the amount of heat possessed by the combustion exhaust gas at the waste heat boiler inlet is used as the physical amount of the waste heat boiler. Provided is a system control device, which is calculated from the temperature and flow rate of combustion exhaust gas at an inlet.

According to the invention according to the second feature, regardless of the size of the time constant of the waste heat boiler, it is possible to control according to the calorific value of the combustion exhaust gas generated in the incinerator, and the calorific value of waste and the like can be controlled. It is possible to improve the responsiveness to fluctuations and setting changes.

The invention according to the third feature is the invention according to the first feature, which is a bag filter for removing soot and harmful components contained in the combustion exhaust gas as a control target, and a control amount in the combustion exhaust gas at the outlet of the bag filter. Provided is a system control device in which the concentration of the acidic gas contained and the supply amount of the neutralizing agent blown into the bag filter are used as the operation amount, and the concentration of the acid gas contained in the combustion exhaust gas at the inlet of the bag filter is used as the physical quantity.

According to the invention according to the third feature, it is possible to control according to the acid gas concentration of the combustion exhaust gas regardless of the size of the time constant of the bag filter, and it is possible to respond to the fluctuation of the acid gas concentration and the setting change. It is possible to improve the sex.

According to the present invention, it is possible to reduce the influence of the time constant of the controlled object, improve the responsiveness, and output without using an expensive control device that requires additional measuring equipment or a complicated calculation algorithm. It is possible to provide a system control device capable of suppressing time fluctuations and increasing the control speed.

FIG. 1 is a schematic diagram showing a waste incineration treatment facility applied as an example of a system control device and a system control method according to the present invention. FIG. 2 is a block diagram showing a preceding control system according to the first embodiment. FIG. 3 shows the result of verifying the responsiveness using the preceding control system according to the first embodiment. FIG. 4 is a block diagram showing a preceding control system according to the second embodiment. FIG. 5 is a schematic view showing a conventional waste incineration treatment facility. FIG. 6 is a block diagram showing a conventional simple feedback control system.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. It should be noted that this is only an example, and the technical scope of the present invention is not limited to this.

[Overall composition of waste incineration facility]
With reference to FIG. 1, the overall configuration of a waste incineration treatment facility applied as an example of the system control device and the system control method according to the present invention will be described.

As shown in FIG. 1, the waste incinerator 1 applied as an example of the system control device and the system control method according to the present invention includes an incinerator 10, a waste heat boiler 20, an exhaust gas cooling device 30, and a bag filter. It is composed of 40, a flue gas stack 50, an incinerator 60, a chimney 70, a control device 80, and a drug supply device 90.

The incinerator 10 incinerates atypical general waste and waste such as industrial waste. In the present embodiment, a vertical waste incinerator is illustrated as an example, but the type of the incinerator 10 may be another type such as a stoker furnace or a fluidized bed furnace.

The incinerator 10 includes a primary combustion air supply means 11a for supplying primary combustion air, a secondary combustion air supply means 11b for supplying secondary combustion air, a cooling water supply means 12 for supplying cooling water for cooling the inside of the furnace, and the like. Is arranged. These are configured so that their respective supply amounts can be changed by a signal from the control device 80 described later.

The waste heat boiler 20 is an economizer that recovers exhaust heat from high-temperature combustion exhaust gas generated when waste is incinerated in an incinerator 10 and heats water supply to generate steam. It is composed of an evaporator that further heats and evaporates the boiler feed water heated by the economizer, a steam drum that separates steam and moisture generated by the evaporator, and the like. Further, a steam amount detecting means 21 for detecting the amount of steam is provided in the main steam pipe for taking out the steam generated in the waste heat boiler 20.

The exhaust gas cooling device 30 reduces the temperature of the combustion exhaust gas discharged from the waste heat boiler 20 to a temperature that can be supplied to the bag filter 40, preferably 200 ° C. or lower. For example, the exhaust gas cooling device is sprayed with cooling water to remove the combustion exhaust gas. It is composed of a cooling tower for cooling.

The bag filter 40 removes soot and harmful components contained in the combustion exhaust gas by filtering the combustion exhaust gas whose temperature has been reduced by the exhaust gas cooling device 30, and is used to filter the soot and harmful components. Including cloth.

The exhaust gas stack 50 is a flue gas stack for connecting between each device such as an incinerator 10, a waste heat boiler 20, an exhaust gas cooling device 30, and a bag filter 40 to circulate combustion exhaust gas. The exhaust gas flue gas stack 50 between the incinerator 10 and the waste heat boiler 20 is provided with an exhaust gas temperature detecting means 51 for detecting the temperature of the combustion exhaust gas and an exhaust gas flow rate detecting means 52 for detecting the flow rate of the combustion exhaust gas. To. It should be noted that such an exhaust gas temperature detecting means 51 and an exhaust gas flow rate detecting means 52 are also installed in a conventional waste incineration treatment facility.

Further, in the flue-gas stack 50 at the inlet of the bag filter 40, an inlet acidic gas concentration detecting means 53 for detecting the concentration of acidic gas such as hydrogen chloride and sulfur oxide contained in the combustion exhaust gas flowing into the bag filter 40 is arranged. At the same time, the flue-gas stack 50 at the outlet of the bag filter 40 is provided with an outlet acidic gas concentration detecting means 54 for detecting the concentration of the acidic gas contained in the combustion exhaust gas flowing out from the bag filter 40.

The attracting ventilator 60 is a ventilator arranged downstream of the bag filter 40, and is for sucking the exhaust gas purified by the bag filter 40 and discharging the exhaust gas from the chimney 70 to the atmosphere.

The control device 80 functions as a system control device in the present invention, and is detected by the steam amount detected by the steam amount detecting means 21, the exhaust gas temperature detected by the exhaust gas temperature detecting means 51, and the exhaust gas flow rate detecting means 52. The combustion air flow rate supplied to the incinerator 10 from the primary combustion air supply means 11a and the secondary combustion air supply means 11b and / or the cooling supplied from the cooling water supply means 12 into the incinerator 10 based on the exhaust gas flow rate. It controls the flow of water and the like. Further, the control device 80 controls the supply amount of the neutralizing agent supplied from the drug supply device 90, which will be described later, based on the acid gas concentration detected by the acid gas concentration detecting means 53.

The chemical supply device 90 supplies a neutralizing agent such as slaked lime to the exhaust gas flue gas stack 50 between the gas cooling device 30 and the bag filter 40, and is configured by a cutting hopper or the like whose supply amount can be adjusted.

[First Embodiment]
The control performed by the system control device in the first embodiment will be described with reference to FIG. FIG. 2 is a block diagram showing a signal flow in the control performed by the system control device according to the first embodiment. The points that overlap with the conventional simple feedback control device 580 described with reference to FIG. 5 will be simplified or omitted, and the points different from those of FIG. 5 will be mainly described.

In the system control device according to the first embodiment, the waste heat boiler 20 that generates steam by utilizing the exhaust heat of the combustion exhaust gas generated in the incinerator 10 as the control target in the present invention, and the waste heat boiler 20 as the control amount. The amount of steam generated, the amount of combustion air supplied to the incinerator 10 and / or the amount of cooling water supplied are applied as the amount of operation, and the amount of steam generated from the waste heat boiler 20 is incinerated so as to follow the control target value. By operating the incinerator 10, the feedback control of the waste heat boiler 20 is performed.

Specifically, the block diagram of the control executed by the system control device in the first embodiment shows the input / output relationship of the incinerator calculation unit F and the waste heat boiler 20 that calculate the input / output relationship of the incinerator 10. In addition to the waste heat boiler calculation unit B, the first adjustment unit C1, the first comparison unit 81, and the addition unit 82, which perform calculations on the above, the second adjustment unit C2 and the second comparison unit 83 are configured.

Note that R (s) is an input, that is, Laplace conversion of the control target value of the steam amount set by a setting device (not shown), and C (s) is an output, that is, waste heat detected by the steam amount detecting means 21. Laplace conversion of the amount of steam generated from the boiler 20, G _c1 (s) is the transfer function from the input to the output in the first adjustment unit C1, and G _c2 (s) is the transfer function from the input to the output in the second adjustment unit C2. G _f (s) is the transfer function from the input to the output in the incinerator 10, G _b (s) is the transfer function from the input to the output in the waste heat boiler 20, and D (s) is the transfer function of the disturbance. Shows Laplace conversion.

The first comparison unit 81 is an input R (s) which is a control target value of the steam amount set by a setting device (not shown), and a steam amount generated from the waste heat boiler 20 detected by the steam amount detecting means 21. The difference of the output C (s) is calculated.

The first adjustment unit C1 inputs the difference between the input R (s) and the output C (s) calculated by the first comparison unit 81, similarly to the adjustment unit 4C shown in the conventional simple feedback control device 580. And the operation amount calculated according to the transfer function G _c1 (s) is output. At this time, the operation amount output from the first adjustment unit C1 is defined as the first operation amount MV1. The first operation amount MV1 output here is the amount of combustion air supplied into the incinerator 10 from the primary combustion air supply means 11a and the secondary combustion air supply means 11b and / or the cooling water supply means. It is a signal about the supply amount of the cooling water supplied from 12 into the incinerator 10.

The second comparison unit 83 is calculated by an exhaust gas calorie calculation means (not shown) using the exhaust gas temperature detected by the exhaust gas temperature detecting means 51 at the inlet of the waste heat boiler 20 and the exhaust gas flow rate detected by the exhaust gas flow rate detecting means 52. The amount of heat possessed by the combustion exhaust gas, that is, the amount of heat of the combustion exhaust gas at the inlet of the waste heat boiler 20 is set as a leading element, the process value PV corresponding to the preceding element, and the first operation amount MV1 output from the first adjusting unit C1. It calculates the difference between. The process value PV referred to here is the amount of combustion air supplied into the incinerator 10 from the primary combustion air supply means 11a and the secondary combustion air supply means 11b, and / / Alternatively, it is a signal regarding the amount of cooling water supplied by the cooling water supply means 12, and can be calculated from the amount of heat of the combustion exhaust gas using a predetermined model.

The addition unit 82 adds the disturbance D (s) to the difference between the first manipulated variable MV1 calculated by the second comparison unit 83 and the process value PV.

The second adjusting unit C2 inputs the input obtained by adding the disturbance D (s) to the difference between the first manipulated variable MV1 and the process value PV calculated by the second comparison unit 83, and the transfer function G _c2 (s). ) Is output as a leading boost element. At this time, the operation amount output from the second adjustment unit C2 is defined as the second operation amount MV2. The second manipulated variable MV2 output from the second adjusting unit C2 becomes an input to the incinerator calculation unit F.

The amount of combustion air supplied into the incinerator 10 from the primary combustion air supply means 11a and the secondary combustion air supply means 11b and / / are adjusted by the first adjustment unit C1 and the second adjustment unit C2. Alternatively, it is the amount of cooling water supplied from the cooling water supply means 12 into the incinerator 10.

Next, a combustion control method using the system control device according to the first embodiment configured in this way will be described.

The combustion control method using the system control device according to the first embodiment is a step of outputting the first operation amount MV1 based on the difference between the control target value and the generated steam amount in the first control unit C1, in the incinerator 10. The step of calculating the process value PV corresponding to the heat amount with the heat amount of the generated combustion exhaust gas as the preceding factor, and the first operation amount MV1 is corrected by outputting the difference between the calculated process value PV and the first operation amount MV1. In the step of adding the disturbance D (s) to the difference between the process value PV and the first manipulated variable MV1 in the adding unit 82, for the difference between the first manipulated variable MV1 and the process value PV in the second adjusting unit C2. A step of outputting the second manipulated variable MV2 based on the sum of the disturbances D (s) and a step of inputting the second manipulated variable MV2 to the incinerator 10 are provided.

Due to such a configuration, the calorific value of the combustion exhaust gas is calculated using the exhaust gas temperature detected by the exhaust gas temperature detecting means 51 and the exhaust gas flow rate detected by the exhaust gas flow rate detecting means 52 as the output of the incinerator calculation unit F. The signal corresponding to the calorific value of the combustion exhaust gas is branched into two. One of the signals corresponding to the amount of heat is an input to the waste heat boiler calculation unit B, and the other is converted into the process value PV corresponding to the amount of heat based on a predetermined model. The process value PV is input to the second adjustment unit C2 by adding the disturbance D (s) after correcting the first operation amount MV1 as a difference from the first operation amount MV1 in the second comparison unit 83. Then, the second operation amount MV2 is calculated in the second adjustment unit C2, and the second operation amount MV2 is input to the incinerator calculation unit F.

In this case, the second adjusting unit C2 functions as a gain for the signal obtained by correcting the first manipulated variable MV1 with the process value PV.

In this way, a one-circle transfer function from the inlet of the waste heat boiler 20 to the inlet of the incinerator 10 is configured, and the heat amount of the combustion exhaust gas is used as a leading element of the steam amount of the steam generated from the waste heat boiler 20, and further preceded. The output C (s) of the feedback system control device to which the operation of giving a gain to the element and boosting it is added is expressed by the equation (4) using the input R (s) and the disturbance D (s).

Comparing the equation (4) expressing the input / output relationship in the system control device according to the first embodiment with the equation (1) expressing the input / output relationship in the conventional simple feedback control device 480, the difference is the input. The denominator of R (s) and the output C (s) is G _c2 (s) G _f (s), which is a term independent of the transfer function G _b (s) of the waste heat boiler 20. That is, the responsiveness is improved by the existence of a term that does not depend on the large time constant T _b of the waste heat boiler 20. That is, by using the heat amount of the combustion exhaust gas as a preceding element of the steam amount of the steam generated from the waste heat boiler 20, the effect of suppressing the time delay can be obtained.

Further, the transfer function G _f '(s) of the small loop is expressed by Eq. (5).

The equivalent gain K _f'and the equivalent time constant T _f'of the equation (5) are as shown in the equation (6) when K _f = 1.

Here, in the formula (6), T _f'decreases by increasing G _c2 (s), which is a preferable result. Further, since K _f'approaches 1 by increasing G _c2 (s), the gain does not decrease even if G _c2 (s) is increased too much. Further, since the gain of G _c1 (s) is not affected, it is possible to make G _c2 (s) sufficiently large.

That is, in the system control device according to the first embodiment, the forward G _c2 (s) by the small feedback circuit is applied, so that the signal is signaled by the second adjusting unit C2 without affecting the gain of the first adjusting unit C1. The gain can be increased, and as a result, not only the effect of suppressing the time delay but also the effect of suppressing the amplitude can be obtained at the same time.

That is, regardless of the size of the time constant of the waste heat boiler 20, it is possible to control according to the calorific value of the combustion exhaust gas generated in the incinerator 10, and the responsiveness to fluctuations in the calorific value of waste and setting changes. Can be improved.

FIG. 3 shows the results of verifying the responsiveness when combustion control is performed using the system device according to the first embodiment. In FIG. 3, (A) when the setting is changed from the steady state, (B) a random response when a disturbance is given based on actual operation data is examined, and a conventional simple feedback control device 580 is used for each. A comparison was made with the results when the control was performed using. Further, (a) shows the results when the gain K _p2 of G _c2 (s) is 2, and (b) shows the results when the same gain is set to 10.

With reference to FIG. 3, in any case, it can be confirmed that the system control device according to the first embodiment obtains a response with a smaller overshoot than the conventional simple feedback system. This is a result of reducing the influence of the large time constant of the waste heat boiler 20. In addition, it can be confirmed that a response with a small vibration width is obtained. This is because the gain of the corrected signal can be increased by adding the forward second adjusting unit C2, and as a result, not only the effect of suppressing the time delay but also the influence of the gain of the first adjusting unit C1 is obtained. This is the result of being able to increase the gain without receiving.

The effect of the system control device according to the first embodiment is physically explained as follows. That is, the combustion exhaust gas generated in the incinerator 10 flows into the waste heat boiler 20 at a predetermined temperature and a predetermined flow rate. The amount of heat possessed by the combustion exhaust gas is calculated by the temperature and the flow rate, but since the outflow of heat from the exhaust gas flue 50 between the incinerator 10 and the waste heat boiler 20 is negligibly small, the heat flow from the waste combustion unit 10 The amount of heat possessed by the exhausted combustion exhaust gas is equal to the amount of heat possessed by the combustion exhaust gas flowing into the waste heat boiler 20. In the present embodiment, the amount of heat possessed by the combustion exhaust gas flowing into the waste heat boiler 20 is detected, and the amount of heat converted into the process value PV such as the amount of combustion air is used as the preceding element of the amount of steam, and further the first adjustment is made. By inputting the positive disturbance D (s) to the one compared with the first operation amount MV1 output from the part C1 and inputting the forward second adjusting part C2, that is, prior to the fluctuation of the steam amount. By adjusting the amount of combustion air and / or the amount of cooling water based on the fluctuation of the amount of heat of the combustion exhaust gas, a factor that is not affected by the time constant of the waste heat boiler 20 is added to the control system as an operation amount, and the time is taken. A control system with little delay is realized. As a result, fluctuations in the amount of steam generated from the waste heat boiler 20 can be suppressed within 3% from the conventional 5%.

At this time, the first manipulated variable MV1 output from the first adjusting unit C1 is compared with the process value PV, and the disturbance D (s) is added to the input, and the manipulated variable is output according to a predetermined transfer function. The adjustment unit is provided as the second adjustment unit C2, and the operation amount output from the second adjustment unit C2 is used as the second operation amount MV2 for the adjustment of the incinerator 10.

By doing so, when the Laplace transform of the output is formulated using the Laplace transform of the input and the disturbance, it is not affected by the term independent of the time constant of the waste heat boiler 20 and the first adjusting unit C1. A term that can increase the signal gain appears, and it is possible to obtain a response that does not depend on the magnitude of the time constant of the waste heat boiler 20 and that does not generate vibration.

Further, since the exhaust gas temperature and the exhaust gas flow rate detected by the exhaust gas temperature detecting means 51 and the exhaust gas flow rate detecting means 52 in the exhaust gas flue gas stack 50 are used for calculating the calorific value of the waste, the conventionally installed detection means are used as they are. Can be controlled. That is, it is possible to perform highly responsive control by utilizing the existing equipment without installing a new measuring device for control.

[Second Embodiment]
The control performed by the system control device in the second embodiment will be described with reference to FIG. FIG. 4 is a block diagram showing a signal flow in the control performed by the system control device according to the second embodiment. The points that overlap with the conventional simple feedback control device 580 described with reference to FIG. 5 will be simplified or omitted, and the points different from those of FIG. 5 will be mainly described.

In the system control device according to the second embodiment, the bag filter 40 is supplied as a control target, the acid gas concentration contained in the combustion exhaust gas at the outlet of the bag filter 40 as the control amount, and the neutralizing agent blown into the bag filter 40 as the operation amount. The amount is applied, and the feedback control of the bag filter 40 is performed by controlling the supply amount of the neutralizing agent so that the acid gas concentration at the outlet of the bag filter 40 follows the control target value.

Specifically, the block diagram of the control executed by the system control device in the second embodiment is a bug filter calculation unit BF, a first adjustment unit C1, and a first calculation for the input / output relationship of the bug filter 40. In addition to the comparison unit 81 and the addition unit 82, it is composed of a second adjustment unit C2 and a second comparison unit 83.

Note that R (s) is an input, that is, the Laplace transform of the control target value of the acid gas concentration set by a setting device (not shown) is detected, and C (s) is an output, that is, the outlet acid gas concentration detecting means 54 is detected. The Laplace transform of the acid gas concentration at the outlet of the bag filter 40, G _c1 (s) is the transfer function from the input to the output in the first adjustment unit C1, and G _c2 (s) is the output from the input in the second adjustment unit C2. G _bf (s) indicates the transfer function from the input to the output in the bug filter 40, and D (s) indicates the Laplace transform of the disturbance.

The first comparison unit 81 has an input R (s) which is a control target value of the acid gas concentration set by a setting device (not shown) and an output C (which is the acid gas concentration detected by the outlet acid gas concentration detecting means 54). s) Calculate the difference.

The first adjustment unit C1 takes the difference between the input R (s) and the output C (s) calculated by the first comparison unit 81 as an input, and sets the first operation amount MV1 calculated according to the transfer function G _c1 (s). Output.

The second comparison unit 83 uses the acid gas concentration detected by the inlet acid gas concentration detecting means 53 as a preceding element, the process value PV corresponding to the preceding element, and the first operation amount output from the first adjusting unit C1. The difference from MV1 is calculated. The process value referred to here is the supply amount of the neutralizing agent supplied from the drug supply device 90, and can be calculated from the acid gas concentration at the inlet of the bag filter 40 by using a predetermined model.

The addition unit 82 adds the disturbance D (s) to the difference between the first manipulated variable MV1 calculated by the second comparison unit 83 and the process value PV.

The second adjusting unit C2 takes the difference between the first manipulated variable MV1 calculated by the second comparison unit 83 and the process value PV plus the disturbance D (s) as an input, and follows the transfer function G _c2 (s). The calculated second operation amount MV2 is output as a leading boost element.

It should be noted that what is adjusted by the first adjusting unit C1 and the second adjusting unit C2 is the supply amount of the neutralizing agent supplied from the drug supply device 90.

Next, a control method using the system control device according to the second embodiment configured in this way will be described.

The control method using the system control device according to the second embodiment is generated in the incinerator, which is a step of outputting the first operation amount MV1 based on the difference between the control target value and the outlet acid gas concentration in the first control unit C1. A step of calculating the process value PV corresponding to the supply amount of the neutralizing agent using the acid gas concentration of the burned exhaust gas as a leading factor, a step of outputting the difference between the calculated process value PV and the first operation amount MV1, and the process. The step of adding the disturbance D (s) to the difference between the value PV and the first manipulated variable MV1, and the second based on the step of adding the disturbance D (s) to the difference between the process value PV and the first manipulated variable MV1. The adjusting unit C2 includes a step of outputting the second operation amount MV2 and a step of inputting the second operation amount MV2 to the bug filter 40.

Due to such a configuration, the acid gas concentration in the combustion exhaust gas at the inlet of the bag filter 40 is detected by the inlet acid gas concentration detecting means 53, and the signal corresponding to the inlet acid gas concentration is branched into two. One of the signals corresponding to the inlet acid gas concentration is an input to the bug filter calculation unit BF, and the other is converted into a process value PV corresponding to the neutralizing agent supply amount based on a predetermined model, and further, the first operation amount MV1. Disturbance D (s) is added after taking the difference with, and becomes an input to the second adjusting unit C2. Then, the second operation amount MV2 is calculated in the second adjustment unit C2 and input to the bug filter calculation unit BF.

By doing so, as in the first embodiment, the forward G _c2 (s) by the small feedback circuit is applied, so that the second adjusting unit C2 does not affect the gain of the first adjusting unit C1. It is possible to increase the signal gain, and as a result, it is possible to provide a control method capable of simultaneously obtaining not only the effect of suppressing the time delay but also the effect of suppressing the amplitude.

That is, regardless of the size of the time constant of the bag filter 40, it is possible to control according to the acid gas concentration of the combustion exhaust gas generated in the incinerator 10, and the responsiveness to the fluctuation of the acid gas concentration and the setting change can be obtained. Can be improved.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments described above. Further, the effects described in the embodiments of the present invention merely list the most suitable effects arising from the present invention, and the effects according to the present invention are limited to those described in the embodiments of the present invention. is not.

For example, as the incinerator 10 in the first embodiment, any type of incinerator such as a stoker type, a fluidized bed type, and a kiln type can be used as long as the waste heat boiler 20 is provided downstream thereof.

Further, the waste heat boiler 20 does not have to be a separate body from the incinerator 10, and the incinerator / boiler integrated type in which the furnace wall of the incinerator 10 is composed of water pipes to form a boiler structure is also included in the present invention. obtain. In that case, the position for detecting the temperature for calculating the amount of heat may be a position downstream of the position where the secondary combustion air is blown, and a position where the exhaust gas and the secondary combustion air are mixed.

Further, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. .. Further, a part of the configuration of each embodiment may be added, deleted, or replaced with another configuration.

The system control device and control method of the present invention can be applied not only to a waste incineration facility but also to various systems including a control target having a large time constant, such as a gas turbine, a motor, a blast furnace, and a chemical plant.

1 Waste incineration facility 10 Incinerator 11a Primary combustion air supply means 11b Secondary combustion air supply means 12 Cooling water supply means 20 Waste heat boiler 21 Steam amount detection means 30 Exhaust gas cooling device 40 Bug filter 50 Exhaust gas stack 51 Exhaust gas temperature detection Means 52 Exhaust gas flow rate detecting means 53 Inlet acid gas concentration detecting means 54 Outlet acidic gas concentration detecting means 60 Inducing ventilator 70 Chimney 80 Combustion control device 81 First comparison unit 82 Addition unit 83 Second comparison unit C1 First adjustment unit C2 No. (Ii) Adjustment unit 90 Drug supply device

The invention according to the first feature is a control target that outputs a predetermined control amount by inputting a predetermined operation amount, and a system control device that adjusts the operation amount to adjust the control amount. In a system control device that performs feedback control of the control target so that the control quantity output from is followed by the control target value, the first operation quantity is output based on the difference between the control target value and the control quantity output from the control target. The signal gain is further increased with respect to the signal obtained by comparing the physical quantity detected at the control target inlet and the physical quantity input to the controlled target with the first manipulated quantity. A system control device, which is provided with an adjustment unit, is provided.

According to the invention according to the first feature, the physical quantity detected at the control target inlet and the control amount can be predicted , and the physical quantity input to the control target functions as a preceding element of the control quantity output from the control target. Therefore, even when the time constant of the controlled object is large, the control can be performed while suppressing the time delay. Further, since the signal gain is further increased with respect to the signal that is a physical quantity that is detected at the control target inlet and the control amount can be predicted and the physical quantity that is input to the control target is compared with the first operation amount, there is a time delay. It is possible to obtain not only the effect of suppressing the response but also the effect of suppressing the amplitude of the response and increasing the control speed at the same time.

Claims (4)

A control target that outputs a predetermined control amount by inputting a predetermined operation amount, and a system control device that adjusts the operation amount to adjust the control amount, and is a control amount output from the control target. In the system control device that performs feedback control of the controlled object so that
A first adjusting unit that outputs a first manipulated variable based on the difference between the control target value and the controlled variable output from the controlled object.
A second adjusting unit for further increasing the signal gain with respect to the signal obtained by comparing the physical quantity detected at the control target inlet and predicting the controlled quantity with the first manipulated variable is provided.
System controller. The waste heat boiler that generates steam by using the exhaust heat of the combustion exhaust gas generated in the incinerator as the control target, the steam amount of the steam generated from the waste heat boiler as the control amount, and the incinerator as the operation amount. The amount of combustion air to be supplied and / or the amount of cooling water supplied is used.
As the physical quantity, the amount of heat possessed by the combustion exhaust gas at the waste heat boiler inlet is calculated from the temperature and flow rate of the combustion exhaust gas at the waste heat boiler inlet.
The system control device according to claim 1. The control target is a bag filter that removes soot and harmful components contained in the combustion exhaust gas, the control amount is the concentration of acid gas contained in the combustion exhaust gas flowing out of the bag filter, and the operation amount is being blown into the bag filter. The amount of Japanese agent supplied is used,
As the physical quantity, the concentration of acid gas contained in the combustion exhaust gas flowing into the bag filter is used.
The system control device according to claim 1. A control target that outputs a predetermined control amount by inputting a predetermined operation amount, and a system control method that adjusts the operation amount to adjust the control amount, and is a control amount output from the control target. In the system control method that performs feedback control of the controlled object so that
A step of outputting the first operation amount based on the difference between the control target value and the control amount output from the control target, and
A step of further increasing the signal gain with respect to the signal obtained by comparing the physical quantity detected at the control target inlet and predicting the control amount with the first operation amount is provided.
System control method.

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