JP5411779B2 - Temperature control device for sludge incinerator and temperature control method for sludge incinerator - Google Patents

Description

  This invention has a sand layer part and a free board part, burns the sludge supplied to the sand layer part, and further burns in the free board part. Temperature control device for fluidized bed sludge incinerator and sludge incinerator This relates to a temperature control method.

  Conventionally, fluidized bed incinerators are frequently used as incinerators that efficiently and reliably burn incinerated materials such as sludge in a short time. In this fluidized bed incinerator, fluidized / combustion air is blown into a fluidized bed through a nozzle to cause the sandy layer constituting the fluidized bed to flow, utilizing the excellent heat transfer characteristics of the sanded layer and the sand. It has a free board which is a combustion chamber for crushing and gasifying the incinerated material and burning the generated gas.

Japanese Patent Laid-Open No. 10-233201 International Publication No. 2009/060885

By the way, in order to cope with recent environmental problems, it is desired to reduce greenhouse gases such as N ₂ O discharged from the sludge incinerator. In order to reduce the greenhouse gas, it is effective to increase the temperature of the free board portion and increase the degree of complete combustion. For example, the greenhouse gas is reduced by about 70% by raising the temperature of the free board portion from 800 ° C. to 850 ° C. On the other hand, the temperature of the sand layer portion needs to be maintained at a certain temperature or higher so that combustion is maintained, and therefore it is necessary to increase the fuel.

  Here, since the conventional PID control can be controlled only for a single target value, a plurality of target values for maintaining the temperature of the freeboard portion at a high temperature while maintaining the temperature of the sand layer portion at a constant temperature. If there is, temperature control is performed by cascade control, etc., but in this case, the flow rate of fuel interferes with the flow rate of flowing air, and excessive supply of fuel due to excessive supply of flowing air occurs, or the temperature of the sand layer part There is a case where the combustion stop due to the lowering may occur, and the stable combustion control may not be performed.

  The present invention has been made in view of the above, and accurately and stably performs temperature control for maintaining the temperature of the free board portion at the target high temperature while maintaining the temperature of the sand layer portion at the target constant temperature. An object of the present invention is to provide a temperature control device for a sludge incinerator and a temperature control method for a sludge incinerator.

  In order to solve the above-described problems and achieve the object, a temperature control device for a sludge incinerator according to the present invention has a sand layer part and a free board part, and burns sludge supplied to the sand layer part, A temperature control device for a fluidized bed sludge incinerator that further combusts in the freeboard section, the temperature of the sand layer section, the temperature of the freeboard section, sludge property information, and discharged from the sludge incinerator. The oxygen concentration, the flow rate of fuel supplied to the lower part of the sand layer part, the air volume of the flowing air supplied to the sand layer part, and the air quantity of air supplied to the middle part of the free board and the upper part of the free board. As a control input, the flow rate of the fuel and the flow rate of the flowing air and the supply air are set as control outputs, and under the constraint conditions that the flow rate of the fuel and / or the flow rate of the flow air and the supply air are within a predetermined range, And performing model predictive control serial sand unit and each temperature of the free board section as different target values.

  Further, in the temperature control device for a sludge incinerator according to the present invention, in the above invention, the constraint condition is that a theoretical flow rate of air necessary for the combustion of the sludge and a theoretical air volume of air necessary for the combustion of the fuel are determined. The air ratio of the flowing air supplied from the lower part of the sand layer and the air supplied from the middle part of the free board is set within a predetermined range with respect to the total theoretical air volume.

  The temperature control device for a sludge incinerator according to the present invention is the above-described invention, wherein the value of the evaluation function indicating the prediction result of the flow rate of the fuel and the flow rate of the flowing air, which is the control output, is a minimum when it is less than a predetermined value. Model predictive control is performed so that

  Moreover, in the temperature control device for a sludge incinerator according to the present invention, in the above invention, when the minimum value of the evaluation function is obtained under the constraint condition, the element of the evaluation function is outside the constraint condition, A penalty function in which an allowable error is given to the upper and lower limits of the predetermined range of the constraint condition to widen the predetermined range of the constraint condition, the expanded constraint condition is used as a modified constraint condition, and the square of the allowable error is multiplied by a predetermined weight A function obtained by adding to the evaluation function is a modified evaluation function, and the minimum value of the modified evaluation function is obtained under the modification constraint condition.

  Further, in the temperature control device for a sludge incinerator according to the present invention, in the above invention, the temperature of the sand layer part and / or the temperature of the free board part is a plurality of temperatures, and each different temperature is targeted. Model predictive control is performed as a value.

  Further, the temperature control method of the sludge incinerator according to the present invention comprises a fluidized bed type having a sand layer part and a free board part, burning the sludge supplied to the sand layer part, and further combusting in the free board part. A temperature control method for a sludge incinerator, the temperature of the sand layer part, the temperature of the free board part, sludge property information, the oxygen concentration discharged from the sludge incinerator, and supplied to the lower part of the sand layer part The control input includes the flow rate of the fuel, the flow rate of the flowing air supplied to the sand layer portion, and the flow rate of the air supplied to the middle portion of the freeboard and the upper portion of the freeboard. The flow rate of the supply air and the flow rate of the fuel and / or the flow rate of the flowing air and the supply air are controlled within the predetermined range, and each of the sand layer portion and the freeboard portion is controlled. Degrees and performing a model predictive control as different target values.

  Further, in the temperature control method for a sludge incinerator according to the present invention, in the above invention, the constraint condition is that a theoretical flow rate of air necessary for the combustion of the sludge and a theoretical flow rate of air necessary for the combustion of the fuel are determined. An air ratio that is a ratio of an actual air flow rate to a total theoretical flow rate is set within a predetermined range.

  Also, in the temperature control method for a sludge incinerator according to the present invention, in the above invention, the value of the evaluation function indicating the prediction result of the flow rate of the fuel and the flow rate of the flowing air and the supply air as the control output is a predetermined value. The model predictive control is performed so as to be minimized below.

  Further, in the temperature control method for a sludge incinerator according to the present invention, in the above invention, when the minimum value of the evaluation function is obtained under the constraint condition, the element of the evaluation function is outside the constraint condition, A penalty function in which an allowable error is given to the upper and lower limits of the predetermined range of the constraint condition to widen the predetermined range of the constraint condition, the expanded constraint condition is used as a modified constraint condition, and the square of the allowable error is multiplied by a predetermined weight A function obtained by adding to the evaluation function is a modified evaluation function, and the minimum value of the modified evaluation function is obtained under the modification constraint condition.

  Further, in the temperature control method for a sludge incinerator according to the present invention, in the above invention, the temperature of the sand layer part and / or the temperature of the free board part is a plurality of temperatures, and each different temperature is targeted. Model predictive control is performed as a value.

  According to this invention, the temperature of the sand layer part, the temperature of the free board part, the sludge property information, the oxygen concentration discharged from the sludge incinerator, the flow rate of the fuel supplied to the lower part of the sand layer part, and the sand layer The flow rate of flowing air supplied to the part, the air volume of air supplied to the free board middle part and the upper part of the free board as control inputs, the flow rate of fuel and the flow rate of flowing air and supply air as control outputs, Model predictive control is performed by setting each temperature of the sand layer portion and the freeboard portion as different target values under the constraint condition that the flow rate of the fuel and / or the flow rate of the flowing air and the supply air are within a predetermined range. Therefore, while maintaining the temperature of the sand layer portion at a constant temperature, temperature control for maintaining the temperature of the free board portion independently at a high temperature can be performed with high accuracy and stability. Since the air ratio obtained from the oxygen concentration can be controlled to be constant, the generation of greenhouse gases can be further suppressed, and further, the flow rate of fuel and the flow rate of flowing air can be reduced, so that the amount of fuel The amount used can be reduced.

FIG. 1 is a schematic diagram showing a schematic configuration of a sludge combustion system including a control device according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing model prediction calculation processing in the control device. FIG. 3 is an explanatory diagram for explaining the optimum value calculation of the evaluation function in the model prediction calculation process. FIG. 4 is a time chart showing measurement results by model predictive control. FIG. 5 is a time chart showing changes in the moisture content of the sludge in the state shown in FIG. FIG. 6 is an enlarged time chart showing changes in the sand layer middle temperature and the freeboard middle temperature shown in FIG. FIG. 7 is a diagram showing a specific comparison result between the conventional control result and the model prediction calculation processing result according to the first embodiment of the present invention. FIG. 8 is a flowchart showing an optimization function processing procedure for evaluation function according to the second embodiment of the present invention.

  Hereinafter, a temperature control device for a sludge incinerator and a temperature control method for a sludge incinerator, which are embodiments for carrying out the present invention, will be described with reference to the drawings.

(Embodiment 1)
1 is a schematic diagram showing a schematic configuration of a sludge combustion system including a control device that is a temperature control device of a sludge incinerator according to Embodiment 1 of the present invention. As shown in FIG. 1, the sludge combustion system 1 has a sludge incinerator 2. The sludge incinerator 2 has a substantially cylindrical shape, and in the furnace is a sand layer portion 5 that forms a fluidized bed, a freeboard middle portion 3 that is an upper space of the sand layer portion 5, and an upper space of the freeboard middle portion 3. And a free board upper part 4.

  Sludge 10 which is dehydrated sludge is supplied to the freeboard middle portion 3 through a sludge property detector 8 having a sludge flow rate detector 20 and a moisture content measuring device 9 and a sludge supply portion 11. Fuel 12 is supplied to the sand layer portion 5 through a valve 41, a fuel flow rate detector 21, and a fuel supply portion 13. The opening degree of the valve 41 is controlled by the fuel flow rate regulator 31 so that the fuel flow rate detected by the fuel flow rate detector 21 becomes the control amount instructed from the control device C.

  The sludge property detector 8 detects the property of sludge and outputs it as sludge property information. The sludge property information includes moisture content, solid content, calorific value and the like. Here, the solid content of the sludge is obtained by solid content = sludge flow rate × (1−water content). In addition, the combustion component can be obtained from the analysis result of the solid component, and the calorific value can be obtained. The sludge flow rate is obtained by the sludge flow rate detector 20, and the moisture content is obtained by the moisture content measuring device 9. Therefore, the sludge property detector 8 can obtain at least the sludge flow rate and the moisture content, and can obtain the solid content therefrom. Moreover, the sludge property detector 8 has a composition component analyzer (not shown) that analyzes the composition component of the solid content, and can obtain a calorific value for the combustion. The moisture content measuring device 9 irradiates the sludge with microwaves, for example, and obtains the moisture content based on the permeability. Specifically, the moisture content is determined using a calibration curve that shows the correlation between the microwave transmission intensity and the moisture content of the sludge prepared in advance.

  Primary air 16, secondary air 17, and tertiary air 18 are supplied to the sand layer portion 5, the freeboard middle portion 3, and the freeboard upper portion 4, respectively. The fluid blower 14 supplies the fluid air 15 to the heat exchanger 19 via the fluid air detector 15 that detects the air volume of the fluid air 15. The heat exchanger 19 heats the flowing flowing air 15 to a predetermined temperature and branches and outputs it to the valves 42, 43 and 44. The primary air temperature controller 32 controls the valve 42 based on the detection result of the primary air flow rate detector 22 so as to supply the controlled air C 16 instructed by the controller C to the sand layer 5. Opening control is performed. Further, the secondary air temperature controller 33 is based on the detection result of the secondary air flow rate detector 23 so as to supply the secondary air 17 of the control amount instructed from the control device C to the freeboard middle part 3. The opening degree of the valve 43 is controlled. Further, the tertiary air temperature regulator 34 is based on the detection result of the tertiary air flow rate detector 24 so as to supply the controlled air tertiary air 18 instructed by the control device C to the freeboard upper part 4. The opening degree of the valve 44 is controlled. A valve 51 is provided on the upstream side of the flow blower 14. The flowing air regulator 50 controls the opening degree of the valve 51 so as to supply the controlled amount of flowing air 15 instructed from the control device C based on the detection result of the flowing air detector 25. Here, the flow air regulator 50 may control the opening degree of the valve 51 so that the flow rate is not a control amount from the control device C but a predetermined constant flow air flow rate. This is because the primary air 16, the secondary air 17, and the tertiary air 18 can be adjusted by the primary air volume regulator 32, the secondary air volume regulator 33, and the tertiary air volume regulator 34, respectively. Because.

  Here, a thermocouple group 26b composed of five thermocouples is dispersedly arranged as a plurality of temperature detectors in the freeboard middle part 3. In the free board upper part 4, a thermocouple group 26c composed of five thermocouples is distributed as a plurality of temperature detection units. Furthermore, in the sand layer portion 5, thermocouple groups 26 a made up of five thermocouples are dispersedly arranged as a plurality of temperature detection portions.

  In the sludge incinerator 2, the sludge 10 supplied to the freeboard middle part 3 in the freeboard middle part 3 is supplied with the fuel 12 and the primary air 16 supplied from the sand layer part 5 and the secondary supplied to the freeboard middle part 3. It burns with air 17. Further, in the freeboard upper part 4, the incompletely burned part in the freeboard middle part 3 is completely burned using the tertiary air 18. The gas burned by the free board upper part 4 is discharged out of the furnace as the exhaust gas 28.

  Oxygen contained in the exhaust gas 28 is detected by an oxygen concentration detector 29. The exhaust gas 28 is discharged through a duct (not shown), and the oxygen concentration detector 29 is provided in this duct. Here, when a cyclone dust collector or a filtration type dust collector is provided in the middle of the duct, it is preferable to provide it before the cyclone dust collector or the filtration type dust collector. Since the latter part of the cyclone dust collector and the filtration type dust collector has dust and ash removed, the oxygen concentration detector 29 is not covered with dust and ash, and the life of the oxygen concentration detector 29 can be extended. It is.

  Here, the control device C includes a sludge property detector 8, a fuel flow rate detector 21, a primary air flow rate detector 22, a secondary air flow rate detector 23, a tertiary air flow rate detector 24, and a flowing air detector 25. The oxygen concentration detector 29 inputs sludge property information, sludge flow rate, fuel flow rate, primary air flow rate, secondary air flow rate, tertiary air flow rate, flowing air flow rate, oxygen concentration, and thermocouple group 26a. To 26c, the sand layer middle temperature, the freeboard middle temperature, and the freeboard upper temperature are inputted, respectively, and the control device C controls the fuel flow rate regulator 31, the primary air volume regulator 32, and the secondary air volume regulators 33, 3 The fuel flow rate, the primary air flow rate, the secondary air flow rate, and the tertiary air flow rate are output to the secondary air flow rate regulator 34 as control amounts, respectively.

  In the control device C, the input sand layer middle temperature, freeboard middle temperature, and freeboard upper temperature are maintained at the set temperatures, the oxygen concentration (air ratio) is within a certain range, the fuel flow rate, the primary Model predictive control is performed so that the air flow rate, the secondary air flow rate, and the tertiary air flow rate are reduced, and the control values of each flow rate and air flow are respectively set to the fuel flow rate detector 21, the primary air flow rate detector 22, and the secondary air flow rate. It outputs to the air volume detector 23 and the tertiary volume detector 24, respectively. The fuel flow rate detector 21, the primary air flow rate detector 22, the secondary air flow rate detector 23, and the tertiary air flow rate detector 24 perform food back control by PID control based on the input control values. Do it separately.

  The control device C includes a model prediction calculation unit 100 as shown in FIG. 2, and the model prediction calculation unit 100 performs model prediction control. Note that model predictive control is control that predicts future outputs and states based on a system model, solves an optimal control problem at fixed time intervals, and determines an input at that time. Moreover, the multi-input / multi-output control peculiar to the modern control is enabled, and the interference of the control amount does not occur. In particular, this model predictive control is attracting attention as a control method capable of handling the constraint conditions because the constraint conditions can be easily described. When this sludge incinerator 2 is controlled, the supply amounts of fuel and air are unknown control amounts that greatly depend on the size of the furnace, etc. As a constraint condition, the respective supply amounts of fuel and air are applied, a plurality of temperature target values of the freeboard middle part 3, the freeboard upper part 4 and the sand layer part 5 are maintained at a constant temperature, and the air ratio obtained from the oxygen concentration is constant. The model predictive control can be performed so that the respective supply amounts of the fuel 12 and the air are reduced while being within the range.

  The model prediction calculation unit 100 generates a dynamic model of the sludge combustion system 1 in advance. Since it is difficult to construct a precise physical model, a step response model is generated here. The step response model is expressed by time and value until the step response when the step input is saturated. In this embodiment, the five middle sand layer temperatures detected by the thermocouple group 26a, the five freeboard middle temperatures detected by the thermocouple group 26b, and the five freeboard upper temperatures detected by the thermocouple group 26c. Then, a step response model is generated for the air ratio obtained from the oxygen concentration 111, the sludge property information 112, the air volume of the primary air 16, the air volume of the secondary air 17, the air volume of the tertiary air, and the flow rate of the fuel 12.

Further, the model prediction calculation unit 100 describes the air ratio constraint condition in the step response model. As described above, the control amounts of the fuel and air are unknown, and the constraint condition of the air ratio is described in the step response model when controlling the fuel and air. Here, the air ratio is the ratio of the minimum required theoretical air amount A for completely burning the fuel to the actually supplied air amount B. For example, the air ratio AFR is:
AFR = fair / (ηcake · fcake + ηfuel · ffuel)
As shown. Here, ηcake is a sludge theoretical air ratio necessary for complete combustion of sludge, fcake is a sludge flow rate, ηfuel is a fuel theoretical air ratio necessary for complete combustion of fuel, and ffuel is , The fuel flow rate. In the air ratio AFR, a constraint condition that falls within the range between the upper limit air ratio rmax and the lower limit air ratio rmin is described.

  Here, the air ratio AFR is obtained directly by detecting the oxygen concentration 112 in the exhaust gas 28. Further, fcake is the flow rate of sludge, and as described above, it is obtained by solid content = sludge flow rate × (1−water content), and further, by analyzing the composition of the solid content, the combustion content is known with high accuracy. be able to. The amount of combustion is obtained from the sludge property information 112. That is, the model prediction calculation unit 100 incorporates control in which the air ratio obtained from the oxygen concentration 112 becomes an air ratio within a certain range under the constraint conditions in the model prediction calculation control of the temperature control. Based on 112, multivariable control is performed in which the flow rate of fuel and the air volume of air are controlled.

  The model prediction calculation unit 100 performs model prediction calculation based on this model. In order to perform this model prediction calculation, as shown in FIG. 2, first, five sand layer middle temperatures, five free boards The set temperature value 101 of the middle temperature and the five free board upper temperatures is input. Further, the constraint condition 102 which is the condition value of the above-described constraint condition is input. For example, the upper limit value and the lower limit value of the air ratio described above. Here, the oxygen concentration (air ratio) set value may be input in the same manner as the set temperature value 101, but here, it is set as a certain range of the air ratio in the constraint condition 102. In addition, the constraint condition 102 is set such that the fuel flow rate and the air flow rate are within a predetermined range. For example, the upper limit value of the freeboard upper temperature may be input as a constraint condition. Further, the calculation condition 103 is input. The calculation conditions are set scales and calculation parameters necessary for actual calculation, such as a calculation period (sampling period) and a prediction period.

  The model prediction calculation unit 100 subjected to such setting processing acquires the current temperature 110 from the thermocouple groups 26a to 26c, performs model prediction calculation for maintaining the temperature set value 101, and the current temperature. Model prediction calculation is performed so that the air ratio determined by the oxygen concentration 111 is within a certain range, and based on the sludge property information 112 and the current operation amount 120 of the input fuel flow rate and air flow rate, The next time manipulated variable 130 of the fuel flow rate and air flow rate is output. Note that the current temperature 110 is set at three locations, that is, the sand layer middle temperature, the freeboard middle temperature, and the freeboard upper temperature. However, the present temperature is not limited to this, and at least two temperatures may be controlled. Therefore, four or more temperatures may be controlled.

  As shown in FIG. 3, the outline of the model prediction calculation is as follows. The known parameter 201 and the current input / output value 202 at the current time (time k) are set as initial values, and the set parameter 203 is used for every predetermined sampling time (k + 1, k + 2, ..., k + N: N is an integer), a state equation representing the predicted input value 200 and the predicted output value 204 is obtained, and an evaluation function J is generated using the predicted output value 204, and an optimal solution for this evaluation function J is obtained. That is, the optimum value calculation for obtaining the minimum value is performed. This optimum value calculation satisfies the constraint condition 102 such as the air ratio, finds the minimum value of each element including the distance of the control error between the temperature setting value 101 and the predicted temperature value, and calculates the predicted input value 200 at this time as Output as a time operation amount 130.

As a result, the temperature control values such as the sand layer middle temperature, freeboard middle temperature, and freeboard upper temperature are controlled to be maintained at a plurality of target values, and the air ratio is controlled to be within a certain range. Further, greenhouse gases such as N ₂ O can be further reduced, the flow rate of fuel and the air volume of air can be kept within a predetermined range, stable control can be performed, and the air ratio can be optimized. Therefore, fuel consumption can be further reduced.

In particular, in this embodiment, since not only the temperature control of each part in the sludge incinerator 2 but also the step response model for the oxygen concentration, that is, the air ratio, is used, the control for the air ratio is further improved. Greenhouse gases such as ₂ O can be further reduced.

FIG. 4 is a time chart showing measurement results when model predictive control is applied to an actual sludge combustion system. Here, the sand layer middle temperature T1 and the freeboard middle temperature T2 are controlled temperatures. The sand layer middle temperature set value is 720 ° C, and the freeboard middle temperature set value is 870 ° C. The measurement is from 0:00 to 24:00. In FIG. 4, the freeboard upper temperature, freeboard middle temperature T2, sand layer middle temperature T1, auxiliary fuel supply amount L1, moisture content, primary air flow rate L11, secondary air flow rate L12, tertiary air flow rate L13, oxygen (O ₂ ). The concentration S1 is shown.

The moisture content of the sludge at this time fluctuates around 80% as shown in FIG. The fuel flow rate L1 fluctuates substantially corresponding to the moisture content. However, regardless of the variation of the moisture content, the sand layer middle temperature T1 and the freeboard middle temperature T2 are maintained at the set values, and the O ₂ concentration S1 is less varied.

  That is, as shown in FIG. 6, the sand layer middle temperature T1 is kept within ± 10 ° C. of the sand layer middle temperature set value = 720 ° C., and the free board middle temperature T 2 is ±± of the free board middle temperature set value = 870 ° C. It is kept within 10 ° C.

Furthermore, as shown in FIG. 7, the N ₂ O emission from the sludge incinerator 2, that is, the N ₂ O mass relative to the solid mass is 0 from the conventional 0.000645 (tN ₂ O / t-cake). .000243 (t-N ₂ O / t-cake). Further, the fuel supply heat amount (supply amount) with respect to the sludge mass is improved from the conventional 1,060 (MJ / t-cake) to 820 (MJ / t-cake). That is, the temperature control is maintained at the target value, the oxygen concentration (air ratio) is within a certain range, and as a result, the N ₂ O emission amount is halved and the fuel supply heat amount (supply amount) is also reduced in each stage. Yes.

(Embodiment 2)
In the model predictive control according to the first embodiment, the calculation is performed with a constraint condition. However, when a severe constraint condition is given, the optimization calculation result of the evaluation function becomes impossible or there is no solution within the constraint condition. The optimization calculation may stop.

Therefore, in this second embodiment, the penalty function f is added to the evaluation function J of the first embodiment.
f = ρε ²
To perform optimization. Here, ε is a tolerance value, and ρ is a weight value.

In the optimization calculation of the first embodiment, the following calculation is performed on the evaluation function J. That is, the minimum value of the evaluation function J is calculated under the constraint condition that the element y (τ) is within the range between the upper limit value ymax and the lower limit value ymin.
min (J) subject to ymin ≦ y (τ) ≦ ymax
On the other hand, in the second embodiment, the following calculation is performed using the penalty function f = ρε ² . That is,
min (J + ρε ² ) subject to ymin−ε ≦ y (τ) ≦ ymax + ε
It is. This is because the upper limit value and the lower limit value are increased by the allowable error ε respectively, and the minimum value of the evaluation function (J + ρε ² ) is substantially larger than the minimum value of the evaluation function J alone, and a penalty function is added. Even when the minimum value is obtained, the minimum value is not selected. As a result, the calculation of the evaluation function does not stop.

  In particular, when the system is started up, if the constraints are severe, the evaluation function may not be optimized. If the evaluation function cannot be optimized, the system startup time will increase. End up. In the second embodiment, continuous system control can be maintained by introducing the penalty function described above, and the system startup time can be shortened.

  Here, with reference to the flowchart shown in FIG. 8, the evaluation function optimization calculation processing procedure according to the second embodiment will be described. First, an optimization calculation for only the evaluation function J is performed without adding a penalty function (step S101). Thereafter, it is determined whether or not the result of the optimization calculation is out of a constraint condition such as no solution (step S102).

If it is outside the constraint (step S102, Yes), the introduced penalty function f = ρε ² described above, spread the upper and lower limits of constraint only allowable error ε min, the evaluation function J in the penalty function f = Ρε ^{2 is} added (step S103), and an optimization calculation is performed (step S104).

  Thereafter, the process proceeds to step S105, or if it is not outside the constraint condition (step S102, No), the process proceeds to step S105 to determine whether or not there is a next optimization operation (step S105). If there is an optimization operation (step S105, Yes), the process proceeds to step S101 and the above-described processing is repeated. If there is no next optimization operation (step S105, No), this processing ends.

  In the second embodiment, since the above-described penalty function is introduced so that the optimization calculation can be continuously performed, the robustness of the control can be improved. In particular, when the system tends to become unstable, such as when the system is started up, it is preferable to introduce a penalty function to perform the optimization calculation.

  In addition, the temperature control apparatus and temperature control method which were mentioned above are applicable besides sludge incinerator. For example, it can be applied to a control system or the like in which blower pressure control and water treatment DO control may interfere with each other, corresponding to the above-described fuel flow control and air flow control. By applying the model predictive control described above to this control system, each control can be stably performed.

  As described above, the temperature control device for a sludge incinerator and the temperature control method for a sludge incinerator according to the present invention have a sand layer portion and a freeboard portion, and burns the sludge supplied to the sand layer portion, It is useful for fluidized bed sludge incinerators that are further burned in the freeboard section.

DESCRIPTION OF SYMBOLS 1 Sludge combustion system 2 Sludge incinerator 3 Free board middle part 4 Free board upper part 5 Sand layer part 8 Sludge property detector 9 Moisture content detector 10 Sludge 11 Sludge supply part 12 Fuel 13 Fuel supply part 14 Fluid blower 15 Fluid air 16 Primary Air 17 Secondary air 18 Tertiary air 19 Heat exchanger 20 Sludge flow rate detector 21 Fuel flow rate detector 22 Primary air flow rate detector 23 Secondary air flow rate detector 24 Tertiary air flow rate detector 25 Flowing air flow rate detector 26a, 26b, 26c Thermocouple group 28 Exhaust gas 29 Oxygen concentration detector 31 Fuel flow rate regulator 32 Primary air air volume regulator 33 Secondary air air volume regulator 34 Tertiary air air volume regulator 41-44, 51 Valve 50 Fluid air Airflow regulator 100 Model prediction calculation unit C Controller

Claims (10)

A temperature control device for a fluidized bed type sludge incinerator having a sand layer part and a free board part, burning sludge supplied to the sand layer part and further burning in the free board part,
The temperature of the sand layer part, the temperature of the freeboard part, sludge property information, the oxygen concentration discharged from the sludge incinerator, the flow rate of fuel supplied to the sand layer part, and the lower part of the sand layer part The flow rate of flowing air and the flow rate of air supplied to the freeboard middle part and the top of the freeboard are set as control inputs, and the flow rate of the fuel and the flow rates of the flowing air and supply air are set as control outputs, Model predictive control is performed by setting each temperature of the sand layer part and the free board part as different target values under a constraint condition that a flow rate of fuel and / or an air volume of the flowing air and supply air are within a predetermined range. A temperature control device for sludge incinerators.   The constraint condition is a predetermined range of an air ratio that is a ratio of an actual air volume of the supplied air to a total theoretical air volume of the theoretical air volume of the supplied air necessary for the combustion of the sludge and the theoretical air volume of the supplied air necessary for the combustion of the fuel. The temperature control device for a sludge incinerator according to claim 1, wherein the temperature control device is inside.   2. The model predictive control is performed so that a value of an evaluation function indicating a prediction result of the flow rate of the fuel and the flow rate of the flowing air and the supply air as the control output is minimized below a predetermined value. Or the temperature control apparatus of the sludge incinerator of 2.   When determining the minimum value of the evaluation function under the constraint condition, if the element of the evaluation function is outside the constraint condition, an allowable error is given to the upper and lower limits of the predetermined range of the constraint condition to determine the predetermined value of the constraint condition A range is expanded, the expanded constraint is set as a modified constraint, a penalty function obtained by multiplying the square of the allowable error by a predetermined weight is added to the evaluation function as a modified evaluation function, and The temperature control device for a sludge incinerator according to claim 3, wherein a minimum value of the modified evaluation function is obtained.   The temperature of the sand layer part and / or the temperature of the free board part is a plurality of temperatures, respectively, and model predictive control is performed with each different temperature as a target value. The temperature control apparatus of the sludge incinerator as described in one. A temperature control method of a fluidized bed sludge incinerator having a sand layer part and a free board part, burning sludge supplied to the sand layer part, and further burning in the free board part,
The temperature of the sand layer part, the temperature of the freeboard part, sludge property information, the oxygen concentration discharged from the sludge incinerator, the flow rate of fuel supplied to the lower part of the sand layer part, and the lower part of the sand layer part The flow rate of the supplied flowing air and the flow rate of the air supplied to the free board middle part and the upper part of the free board are set as control inputs, and the flow rate of the fuel and the flow rate of the flowing air and the supply air are set as control outputs, Model predictive control is performed by setting each temperature of the sand layer part and the free board part as different target values under the constraint condition that the flow rate of the fuel and / or the flow rate of the flowing air and the supply air are within a predetermined range. A characteristic temperature control method for a sludge incineration channel.   The constraint condition is a predetermined range of an air ratio that is a ratio of an actual air volume of the supplied air to a total theoretical air volume of the theoretical air volume of the supplied air necessary for the combustion of the sludge and the theoretical air volume of the supplied air necessary for the combustion of the fuel. The temperature control method for a sludge incinerator according to claim 6, wherein the temperature control method is used.   7. The model predictive control is performed so that a value of an evaluation function indicating a prediction result of the flow rate of the fuel and the flow rate of the flowing air and supply air as the control output is minimized below a predetermined value. Or the temperature control method of the sludge incinerator of 7.   When determining the minimum value of the evaluation function under the constraint condition, if the element of the evaluation function is outside the constraint condition, an allowable error is given to the upper and lower limits of the predetermined range of the constraint condition to determine the predetermined value of the constraint condition A range is expanded, the expanded constraint is set as a modified constraint, a penalty function obtained by multiplying the square of the allowable error by a predetermined weight is added to the evaluation function as a modified evaluation function, and 9. The temperature control method for a sludge incinerator according to claim 8, wherein a minimum value of the modified evaluation function is obtained.   The temperature of the sand layer part and / or the temperature of the free board part is a plurality of temperatures, respectively, and model predictive control is performed with each different temperature as a target value. The temperature control method of the sludge incinerator as described in one.

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