JP2790780B2 - Incinerator combustion control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control device for an incinerator, and more particularly to a combustion control device for a fluidized bed incinerator for incinerating or pyrolyzing municipal solid waste and industrial waste.

[0002]

2. Description of the Related Art Various types of incinerators have been developed to efficiently treat municipal waste, industrial waste, and the like, which are increasing in number in recent years, by incineration or thermal decomposition. Fluid bed incinerators are one of them. For example, in this furnace, sand is charged into the furnace, air is blown into the furnace from the bottom to fluidize the sand, and refuse is put into the furnace. And heat and thermally decompose it uniformly. A method has been developed to control the furnace temperature so that it can deal with various types of waste.
The present inventors have developed a device that performs control by using a so-called adaptive identification method (Japanese Patent Application No. 5-25151).
No. 0 etc.). Here, a model of the controlled object is set up by inputting the refuse supply conveyor speed for feeding refuse into the refuse incinerator and outputting the furnace top temperature. A primary model such as the following equation is used as a combustion model. y [k + 1] + ay [k] = bu [k] (1) where y [k] is the output (difference between the measured value of the furnace top temperature and the reference temperature), and u [k] is the input ( Conveyor speed), a and b are unknown parameters. Therefore,
Obtaining the parameters a and b is the purpose of identification. For this purpose, the following adaptive identification method, which is an adaptive identification method with a dead zone, is used.

(Equation 1) Here, a _e [k] and be _e [k] are estimated values of a and b, and W
_l <0, W _u > 0 are the lower limit, upper limit, and 0 <
λ <1 is a forgetting factor. Here, it is conceivable to change the method of calculating the dead zone in the above equation (3) as follows.

[0003]

(Equation 2) In this way, by changing the dead zone, it is possible to respond more quickly to fluctuations in the dynamic characteristics of the plant. By using this identification method, the dynamic characteristic model is identified in a form excluding the influence of disturbance. Control is performed using this identification method. However, if the conveyor speed is changed too much, it becomes difficult to stabilize the combustion state of the incinerator. In consideration of these facts, a control system B0 as shown in FIG. 4 is formed. In the control system B0, the furnace top temperature is controlled by the feed forward gain C and error feedback through a digital filter. The feedforward gain C is a real number determined by a parameter obtained by the identification, and is calculated by the following equation using the final value theorem so that the output matches the target value when there is no disturbance. _{C = (1-a e)} / b e ... The (11), the feedback effect reduction of the output disturbance by using the error of (furnace top temperature) and the target value (the variation of how laid-dust) It is carried out. Furthermore, by adding a digital filter to this feedback loop, control of the vibration characteristic peculiar to each plant is achieved.

[0004]

The above-described conventional combustion control system for an incinerator has the following problems.
That is, since the dynamic characteristics of a refuse incinerator are slow in time, higher accuracy can be expected if the cycle is made longer to some extent for identification. On the other hand, it is desirable to change the manipulated variable in a short cycle in order to cancel the influence of disturbance on the furnace. However, assuming that the period of identification and the change of the manipulated variable are different, the identification side assumes that the value of the manipulated variable does not change within one cycle, so this could not be realized. In order to solve the problems in the conventional technology, the present invention improves the combustion control device of the incinerator and separates the period of the identification unit and the control unit in adaptive control, thereby improving the performance of the entire control system. It is an object of the present invention to provide an incinerator combustion control device capable of improving the combustion efficiency.

[0005]

In order to achieve the above object, the present invention comprises a first detecting means for detecting a control amount relating to a combustion state of an incinerator and a detecting means for detecting an operation amount applied to the incinerator. A transfer function representing a relationship between the control amount and the operation amount based on a second detection unit and a control amount detected by the first detection unit and an operation amount detected by the second detection unit; A first calculating means for calculating the coefficient by using the adaptive identification technique, and the operation amount such that the control amount becomes a desired value by using the coefficient calculated by the first calculating means. In the combustion control apparatus for an incinerator provided with a second calculating means, an average calculating means for averaging the manipulated variables detected by the second detecting means at predetermined time intervals and sending the average to the first calculating means. Combustion of incinerator characterized by providing It is configured as a control device. Further, the second arithmetic means is a combustion control apparatus for an incinerator which compensates for a disturbance applied to the incinerator by using a coefficient calculated by the first arithmetic means with respect to a target value inputted from the outside. . Further, the second arithmetic means is operated by the first arithmetic means for a deviation-added target value obtained by incorporating a deviation of the control amount detected by the first detection means from the target value into the target value. This is a combustion control device for an incinerator that compensates for disturbance applied to the incinerator using the calculated coefficient. Further, the second arithmetic means is:
And a third calculating means for calculating a counter component for canceling a predetermined component included in the deviation of the control amount from the target value detected by the first detecting means, wherein the counter component calculated by the third calculating means is included. An incinerator combustion control device for compensating for a disturbance applied to the incinerator by using a coefficient calculated by the first arithmetic unit with respect to a target value with a competing component in which the component is incorporated into the target value. Furthermore, the first
The incinerator combustion control device performs the calculation of the coefficient of the transfer function by the calculating means based on a dead zone against a calculation error. Further, there is provided a combustion control apparatus for an incinerator wherein the width of the dead zone is different between the plus side and the minus side. Further, it is a combustion control apparatus for an incinerator wherein the control amount is the temperature inside the incinerator. Further, in the incinerator combustion control device, the control amount is the amount of steam generated by the boiler using the exhaust gas from the incinerator. Further, it is a combustion control apparatus for an incinerator, wherein the operation amount is a supply amount of the burnable material. Further, when the incinerator is a fluidized bed incinerator, the present invention relates to a combustion control device for an incinerator using a supply amount and / or temperature of primary air as an operation amount in addition to the operation amount. Further, when the incinerator is a fluidized bed incinerator, the present invention relates to a combustion control apparatus for an incinerator using a supply amount and / or temperature of secondary air as an operation amount in addition to the operation amount.

[0006]

According to the present invention, the control amount relating to the incineration state of the incinerator is detected by the first detecting means, the operation amount applied to the incinerator is detected by the second detecting means, and the first detecting means detects the control amount. Based on the control amount detected by the detection means and the operation amount detected by the second detection means, the coefficient of the transfer function representing the relationship between the control amount and the operation amount is determined using an adaptive identification method. When the operation amount is calculated by the second calculation unit using the coefficient calculated by the first calculation unit so that the control amount becomes a desired value, The operation amount detected by the second detection means is averaged at predetermined time intervals by the average calculation means and sent to the first calculation means. Therefore, it is possible to separate the periods of the first arithmetic means as the identification unit and the second arithmetic means as the control unit in the adaptive control, and to control the combustion of the incinerator by changing the quality of the material to be burned. While always accurately grasping the change in characteristics between input and output,
Control with high responsiveness to disturbance can be realized. As a result, the performance of the entire control system can be greatly improved.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention. The following embodiment is an example embodying the present invention and is not intended to limit the technical scope of the present invention. Here, FIG. 1 is a schematic diagram showing a schematic configuration of an incinerator combustion control apparatus A1 according to one embodiment of the present invention, FIG. 2 is a control block diagram of the above-described apparatus A1, and FIG. 3 is another embodiment of the present invention. It is a schematic diagram which shows schematic structure of the combustion control apparatus A2 of the incinerator which concerns on FIG.
As shown in FIG. 1, one embodiment of the present invention (first embodiment)
The incinerator combustion control device A1 according to the first embodiment includes a sensor 2 (corresponding to a first detection unit) for detecting a control amount related to a combustion state of the incinerator 1, and a sensor 3 for detecting an operation amount applied to the incinerator 1. A parameter which is a coefficient of a transfer function representing a relationship between the control amount and the operation amount based on the control amount detected by the sensor 2 and the operation amount detected by the sensor 3. And a parameter identification device 4 (corresponding to a first calculation means) for calculating the control amount using an adaptive identification method, and using the parameters calculated by the parameter identification device 4 so that the control amount becomes a desired value. It is the same as the conventional example in that it has a manipulated variable computing device 5 (corresponding to a second computing means) for computing the quantity. However, in the first embodiment, there is provided an average value calculator 6 (corresponding to an average value calculator) which averages the operation amount detected by the sensor 3 every predetermined time and sends it to the parameter identification device 4. Is different from the conventional example.

Hereinafter, the operation and principle of the apparatus A1 will be described. As shown in FIG. 1, the incinerator 1 is supplied with refuse by a conveyor, and burns in a sand layer fluidized by primary air. The combustion gas rises to the upper part of the incinerator 1, is mixed with the secondary air, is completely burned, and is discharged as exhaust gas. With respect to the incinerator 1, stabilization control of the furnace top temperature is performed using the control amount as the furnace top temperature and the operation amount as the waste supply conveyor speed. The control system includes an identification unit including a parameter identification device 4 and an average calculator 6;
And a control unit represented by the manipulated variable operation device 5. The cycle is different between the identification unit and the control unit, and the control unit changes the operation amount n times during one cycle of the identification unit. That is, assuming that the cycle of the control unit is T, the cycle of the identification unit can be represented as nT using a natural number n. However,
The operation timing of the identification unit coincides with that of the control unit. The identification unit performs parameter identification using the average value calculated by the average value calculator 6 and the furnace top temperature measured by the sensor 2 for each cycle nT, and sends updated parameters to the control unit. In the control unit, the temperature and speed for each cycle T,
Using the parameters from the identification unit, the conveyor speed is calculated so as to keep the furnace top temperature constant, and sent to the conveyor as a speed command value. FIG. 2 is a block diagram of the control system B1 of the device A1. In the identification unit in FIG. 2, the identification model is updated at a cycle nT based on the input / output relationship of the incinerator 1. Thus, the model of the identification unit always follows the dynamic characteristics of the actual waste incinerator 1. In the control unit, the manipulated variable calculator changes under the influence of the change in the identification model, and performs control applied to changes in the dynamic characteristics of the furnace (changes due to fluctuations in waste quality, etc.).

Here, the details of the calculation algorithm of each unit in the apparatus A1 will be described. Assuming that the combustion characteristic of the incinerator 1 is a linear first-order lag system, the input / output relationship in real time (continuous time) can be expressed by the following equation.

(Equation 3) Here, the input signal is u (t) and the output signal is y (t). When the input u (t) is fixed for a fixed time from a certain time t, its output can be expressed by the following equation using the output at the time t.

(Equation 4) Then, the above equation (13) can be rewritten as the following equation. That is, a linear first-order lag system discretized with the period δt is obtained. Since the identification is performed in discrete time, the parameters a and b in the following equation are estimated. y (t + δt) = ay (t) + bu (t) (14) Based on the above, the combustion of the incinerator 1 will be further considered.
One of the characteristics of the combustion of the incinerator 1 is its time constant. This means that the constant A is 0 in the above description.
It corresponds to being near. Accordingly, it can be seen that the parameter a approaches 1 when the period δt is shortened when identifying the dynamic characteristics. The absolute value of parameter a is 1
The above indicates that the system represented by the above equation (14) is unstable. In the numerical calculation, the parameter a
Is close to 1, the estimated value of the parameter a tends to be 1 or more, and therefore, the identification model tends to be unstable. If the model becomes unstable, it will have an adverse effect on the overall control using it. In addition, the accuracy of subsequent identification deteriorates. Therefore, in performing the control, it is necessary to increase the identification cycle to some extent and to reduce the absolute value of the parameter a. This is consistent with the problem described in the conventional example.

On the other hand, in order to suppress the influence of disturbance acting on the incinerator 1, it is necessary to perform control in a short cycle capable of quickly coping with these. Therefore, it is considered that the periods of the identification unit and the control unit are separated. However, this means that the input changes within one cycle of the identification, and the condition for deriving the above equation (14) is broken. For this reason, an ordinary identification method cannot be used. Therefore, the input is changed from time t to width δt.
When the output is changed n times in a stepwise manner, the output value at this time is expressed by the following equation.

(Equation 5) Here, u (i) represents the i-th input value. Where e
When xp (t) is close to 0, linear approximation can be performed. Therefore, when the constant A is close to 0, and the period δt and the natural number n are sufficiently small, the following equation approximately holds.

(Equation 6) As described above, since the time constant of the incinerator 1 is large, this approximation formula is appropriate depending on how to select the period of the identification unit. Therefore, a control system can be constructed by separating the periods of the identification unit and the control unit. From the above, the following can be said. In adaptive control, it is possible to separate the cycle of the identification unit and the control unit. In the combustion control of the incinerator, changes in the characteristics between input and output due to fluctuations in the quality of the material to be burned are always accurately grasped, and the Highly responsive control can be realized.

That is, in the identification unit, since the period can be made longer, the characteristics of the object can be grasped globally with higher accuracy. For this reason, ignoring the influence of the fine disturbance also contributes to the improvement of the identification accuracy. In the control section, since the cycle can be set shorter, the reaction time to disturbance can be shortened, and control performance can be improved. In addition, since the identification accuracy has been improved,
The performance of the entire control system can be improved. Further, another embodiment of the present invention (second to fourth embodiments)
Will be schematically described with reference to FIG. However, the second to fourth
As shown in FIG. 3, the device A2 according to the second embodiment is positioned as a more specific device of the device A1 according to the first embodiment. In the second embodiment, the manipulated variable calculation device 5 in the first embodiment uses the parameters calculated by the identification model of the parameter identification device 4 for the externally input target value to apply a disturbance to the incinerator 1. Is compensated for. That is, the manipulated variable calculator of the manipulated variable calculator 5 is configured with the same feed-forward gain C as in the conventional example, and by performing disturbance compensation, the influence of disturbance can be reduced. The third
In the second embodiment, the manipulated variable calculating device 5 in the first embodiment uses the parameter identification device 4 for a deviation-added target value obtained by incorporating the deviation of the furnace temperature detected by the sensor 2a from the target value into the target value. The compensation for the disturbance applied to the incinerator 1 is performed using the parameters calculated by the identification model. That is, a change in the manipulated variable is suppressed by using the fed-back deviation from the target value of the furnace top temperature as the input to the manipulated variable calculator of the manipulated variable calculator 5 by incorporating the deviation into the target value. be able to. For example, if an ideal change in the furnace temperature from the start to the stop of the incinerator 1 is set as a characteristic curve of a target value, and a curve of an operation amount corresponding to this characteristic curve is set in advance, the operation amount The change from the curve is only the amount corresponding to the deviation. Thus, disturbance control can be performed while suppressing a change in the operation amount.

Further, in a fourth embodiment, the manipulated variable calculating device 5 in the first embodiment is provided with a counter component for canceling a predetermined component included in a deviation from a target value in the furnace temperature detected by the sensor 2a. And compensates for the disturbance applied to the incinerator 1 by using the parameters calculated by the identification model of the parameter identification device 4 for the target values with the counter components obtained by incorporating the calculated counter components into the target values. It is. That is, by adding a digital filter (corresponding to the third calculating means) to the feedback loop, it is possible to suppress vibration characteristics and the like peculiar to the incinerator 1 to be controlled. However, even in these first to fourth embodiments, similarly to the conventional example, the parameter a _e of the transfer function by the parameter identification unit 4, b _e
In the calculation of, a dead zone for a calculation error is used. Therefore, stable control can be performed without reflecting each minute error in such a dead zone in parameter calculation. Further, by independently determining the upper and lower widths of the dead zone, when increasing the sensitivity of adaptive identification, for example, it is possible to increase only one of the sensitivity of increasing and decreasing the furnace temperature. As a result, the amount of operation can be arbitrarily increased or decreased. That is, by changing the dead zone, it is possible to respond more quickly to fluctuations in the dynamic characteristics of the incinerator 1. Thereby, good controllability is obtained. Further, in the first to fourth embodiments, the furnace temperature of the combustion furnace 1 is used as the control amount. However, in actual use, the amount of steam generated in the boiler 7 using the exhaust gas of the incinerator 1 is measured. 2b, and control may be performed using this to improve the combustion efficiency of the entire incinerator system.

Further, the combustion control itself can be performed by operating at least the amount of refuse supplied as detected by the sensor 3a. However, if the specified amount of waste cannot be incinerated by this control, the temperature of the furnace will be lowered by manipulating the amount of secondary air to reduce the furnace temperature atmosphere. It is effective to achieve the specified amount of incineration of the incinerator 1 without exceeding it. For this purpose, a sensor 3d is provided in FIG. Further, by performing control by adding the secondary air temperature, the primary air amount, the primary air temperature, and the like as the manipulated variables, the range of adjustment of the amount of waste incineration can be further widened. For this reason, in FIG. 3, the sensors 3e, 3
b, 3c are provided. Since a wide range of control amounts and operation amounts can be selected in this manner, better controllability can be obtained. In the first embodiment, the characteristic of the control target is set to 1
Although a second-order delay system is assumed, this method can also be used when the dynamic characteristics are assumed to be higher-order under the same condition that the time constant of the controlled object is large. In the first to fourth embodiments, the temperature control device of the fluidized bed incinerator is exemplified. However, in actual use, the present invention can be applied to other types of incinerators, for example, fixed bed incinerators. No problem.

[0014]

Since the present invention is configured as described above, it is possible to separate the periods of the first arithmetic means as the identification unit and the second arithmetic means as the control unit in the adaptive control. In controlling the combustion of the incinerator, it is possible to realize highly responsive control with respect to disturbance while always accurately grasping the change in the characteristics between input and output due to the change in the quality of the burned material. As a result, the performance of the entire control system can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a combustion control device A1 of an incinerator according to one embodiment of the present invention.

FIG. 2 is a control block diagram of the device A1.

FIG. 3 is a schematic diagram showing a schematic configuration of a combustion control device A2 of an incinerator according to another embodiment of the present invention.

FIG. 4 is a control block diagram of an example of a conventional incinerator combustion control device A0.

[Explanation of symbols]

 A1: combustion control device 1: incinerator 2: sensor (corresponding to first detecting means) 3: sensor (corresponding to second detecting means) 4: parameter identification device (corresponding to first calculating means) 5. operation Quantity calculating device (corresponding to second calculating means) 6... Average value calculating device (corresponding to mean value calculating means)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F23G 5/50 ZAB F23G 5/50 ZABN G05D 23/19 G05D 23/19 J (56) JP-A-4-208305 (JP, A) JP-A-57-117013 (JP, A) JP-A-7-103444 (JP, A) JP-A-6-337705 (JP, A) 7-182009 (JP, A) JP-A 2-69222 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F23C 11/02 F23G 5/30 F23G 5/50 G05D 23 / 19

Claims (11)

(57) [Claims] 1. A first detecting means for detecting a control amount related to a combustion state of an incinerator, a second detecting means for detecting an operation amount applied to the incinerator, and a detection by the first detecting means. A first function of calculating a coefficient of a transfer function representing a relationship between the control amount and the operation amount by using an adaptive identification method based on the control amount and the operation amount detected by the second detection means; An incinerator combustion control device comprising: an arithmetic unit; and a second arithmetic unit that calculates the operation amount so that the control amount becomes a desired value using the coefficient calculated by the first arithmetic unit. A combustion control device for an incinerator, characterized in that an average calculation means for calculating an average of operation amounts detected by the second detection means at predetermined time intervals and sending it to the first calculation means is provided. . 2. The incineration according to claim 1, wherein said second calculation means compensates for a disturbance applied to said incinerator by using a coefficient calculated by said first calculation means with respect to a target value input externally. Furnace combustion control device. 3. The second calculating means calculates a deviation from a target value of the control amount detected by the first detecting means, and calculates a deviation from the target value by using the first calculating means. The combustion control apparatus for an incinerator according to claim 1, wherein compensation for disturbance applied to the incinerator is performed using the calculated coefficient. 4. The third computing means, wherein the second computing means computes a counter component for canceling a predetermined component included in a deviation of the control amount detected from the target value detected by the first detecting means. And compensating for a disturbance applied to the incinerator using the coefficient calculated by the first calculating means with respect to the target value with the counter component obtained by incorporating the counter component calculated by the third calculating means into the target value. The incinerator combustion control device according to claim 1, which performs the operation. 5. The combustion control apparatus for an incinerator according to claim 1, wherein the first calculating means calculates the coefficient of the transfer function based on a dead zone against a calculation error. 6. The combustion control device for an incinerator according to claim 5, wherein the width of the dead zone is different between the plus side and the minus side. 7. The incinerator combustion control device according to claim 1, wherein the control amount is an incinerator temperature. 8. The combustion control apparatus for an incinerator according to claim 1, wherein the control amount is a steam generation amount of a boiler using exhaust gas of the incinerator. 9. The combustion control device for an incinerator according to claim 1, wherein the operation amount is a supply amount of the burnable material. 10. The combustion control of an incinerator according to claim 9, wherein when the incinerator is a fluidized bed incinerator, a supply amount and / or temperature of primary air is used as an operation amount in addition to the operation amount. apparatus. 11. The combustion of an incinerator according to claim 10, wherein when the incinerator is a fluidized bed incinerator, a supply amount and / or temperature of secondary air is used as an operation amount in addition to the operation amount. Control device.