JPH09264502A - Method for controlling dust incineration boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a smooth combustion to be carried out for an intermittent period of combustion by a method wherein a control value of dust transporting speed of a stoker formed in response to a set value of dust layer thickness is limited by a value of an estimated amount of combustion. SOLUTION: At an air volume control section, a set amount of air eX of a stoker is calculated under a PID control in response to a set value of an amount of steam. At a stoker speed control section, a set transporting speed of the stoker is calculated under the PID control in response to a set dust layer thickness (p). A set transporting speed (g) of the stoker outputted from a PID calculator 95 is limited by an upper value or lower value limiter 96 and then outputted to a stoker motor driving section. A limited value (s) of the upper value or lower value limiter 96 is formed by a function generator 97 with an estimated combustion amount (f) outputted from the estimated combustion amount generating section. When the estimated combustion amount (f) is lower than a specified value at the function generator 97, the upper limit value is limited to a minimum value and in turn, when the estimated combustion amount is larger than the specified value, this value is increased in proportion to the estimated combustion value (f).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a refuse incineration boiler for incinerating general waste, industrial waste, etc., in which calorific value calculation is difficult to set in advance.

[0002]

2. Description of the Related Art As a conventional method for controlling a refuse incinerator boiler, combustion air is gradually phased by a general sequence control and control loop for executing an operation based on a temperature rise / fall curve of the furnace temperature. A method is used to change the amount, the supply, transfer, discharge, and speed of waste in the furnace.

[0003]

However, the conventional method for controlling a refuse incinerator boiler has the following problems. 1. A control structure that takes into account the fact that the composition of waste changes depending on factors such as the season, collection place, and social environment is required. 2. Parameter setting based on incineration experience is required,
We cannot guarantee the quality of inexperienced waste and the reproducibility is poor. 3. The control program becomes complicated and adjustment time is required. 4. It is very difficult to faithfully achieve the temperature rising / falling curve, and the action of the control loop when the deviation becomes too large becomes an excessive operation.

In view of the above, according to the present invention, the operation of the control loop eliminates the excessive operation, the combustion in the combustion transition period can be made smooth, and the self-correction can be performed in response to the change of the waste quality. It is an object of the present invention to provide a control method of.

[0005]

In order to achieve the above object, a method of controlling a refuse incinerator according to claim 1 is to convey refuse continuously by a stoker and incinerate by sending air from below the stoker. , A method of controlling a waste incineration boiler that generates steam, wherein a target value of the amount of steam generated is continuously generated at a predetermined rate of change, and an estimated incineration amount value is obtained from the target value of steam generation and the estimated heat generation amount of waste. Is formed, the control value of the feed air amount to the stoker that is formed based on the steam generation target value is limited by the estimated incineration amount value, and the stoker that is formed based on the set value of the dust layer thickness. It is characterized in that the control value of the refuse transportation speed is limited by the estimated incineration amount value.

According to the above method, the amount of air sent to the stoker and the dust conveying speed of the stoker are limited by the estimated incineration amount value during the combustion transition period, and the combustion state gradually changes. Therefore, the combustion curve in the combustion transition period becomes smooth.

A waste incinerator control method according to a second aspect of the present invention is the waste incinerator control method according to the first aspect, in which the steam generation target value is determined by the difference between the steam generation target value and the actual steam generation amount. It is characterized in that a predetermined rate of change is corrected.

According to the above method, when the amount of steam generation changes due to the change in the quality of dust, the predetermined change rate of the steam generation target value is corrected accordingly. Therefore, it is possible to perform control in accordance with changes in the quality of waste.

Further, a control method for a refuse incinerator according to claim 3 is the method for controlling a refuse incinerator according to claim 1, characterized in that the estimated calorific value of the refuse is corrected by the refuse conveying speed of the stoker. It is what

By the above method, the estimated calorific value of dust is corrected by the stoker transport speed corresponding to a predetermined amount of steam and the actual stoker transport speed. Therefore, the estimated incineration amount of waste corresponding to the steam generation target value is calculated in accordance with the change in waste quality.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 7 is a schematic configuration diagram of the refuse incinerator according to the embodiment of the present invention.

The waste 2 put into the waste incineration boiler 1 is
It is continuously conveyed by the stoker 3, and further, the air 4 is sent from below to be burned, and the combustion gas 5 is guided to the superheater 6 to generate steam and then discharged.

A variable speed motor is used to drive the stoker 3.
11 is used, and the rotation speed of the motor 11 is controlled by the inverter 12 on the basis of a command from the control device which will be described later, so that the conveying speed of the dust 2 by the stoker 3 is controlled.

Further, the air 4 sent to the stove 3 is supplied by a forced air blower 13, and a variable speed motor 14 is used to drive the blower 13, and an inverter 15 drives this motor based on a command from a controller described later. By controlling the rotation speed of 14, the amount of air 4 sent to the stoker 3 is controlled.

Further, the layer thickness of the dust 2 conveyed by the stoker 3 is detected by the detector 17, and the amount of vapor generated by the superheater 6 is detected by the detector 18 by its pressure and temperature.

The control device 21 of the refuse incineration boiler 1 using the control method of the present invention is composed of a microcomputer, as shown in FIG.
As shown in FIG. 3, the waste incineration boiler 1 is connected to the operation panel 22, the detectors 17 and 18, the inverter 12 of the stoker 3, and the inverter 15 of the forced draft blower 13.

The operation panel 22 includes a start / stop switch 31,
It consists of a startup / shutdown start switch 32, a calorific value setter 33 for setting the amount of waste heat generation, a steam amount setter 34 for setting the target steam amount, and a dust layer thickness setter 35 for setting the dust layer thickness. There is.

As shown in FIG. 6, the setting devices 33, 34 and 35 have "manual" and "automatic" selection switches 41 and 42, respectively, and "up" and "down" of set values operable in the manual mode. Push button switches 43 and 44 and a meter 45 for displaying the set value are provided, and when the manual mode is selected by the "manual" selection switch 41, pushing operation of the "up" and "down" push button switches 43 and 44 is performed. The set value (pointer position of the meter 45) is changed by the, and when the automatic mode is selected by the "automatic" selection switch 42, the heat generation amount setter 33 outputs the UP / DOWN signal (described later) from the control device 21. Setting value is changed stepwise, and the steam amount setter 34 outputs the steam amount set value (described later) output from the control device 21 as it is.

As shown in FIG. 1, the control device 21 includes a sequence control unit 51, an estimated incineration amount generation unit 52, an air amount control unit 53,
The blower motor drive unit 54, the stoker speed control unit 55, and the stoker motor drive unit 56 (all of which will be described later) are included.

The sequence section 51 includes a start / stop switch 31 of the operation panel 22 and a start / stop start switch 32.
Is connected and outputs a start or stop execution signal to the blower motor drive unit 54 and the stoker motor drive unit 56 in response to the start / stop switch 31 to start and stop the push blower 13 and the stoker 3. When a process determined in advance according to the start-up / shutdown start-up switch 32 is reached, an execution signal for start-up control or fall control is output to the estimated incineration amount generation unit 52.

The estimated incineration amount generation unit 52 includes a calorific value setting device 3
3, the steam quantity setting device 34 is connected, and as shown in FIG. 2, the RS flip-flop 61 is set by the execution signal of the rising control input from the sequence section 51 and reset by the execution signal of the falling control. And a relay 62 that is excited by the output of the RS flip-flop 61, and a setter 63 that is set to a rated steam amount and a steam amount "
A second setter 64 set to 0 ″ is provided, and the set values of the steam amounts of the setters 63 and 64 are switched by the contacts of the relay 62 and set to the target value a of the steam amount.

The target value a of the steam amount is the steam amount set value b.
The deviation c is calculated by the subtracter 65, and the deviation c is limited by the upper and lower limiter 66 {limit value d (described later)} and integrated by the integrator 67 to obtain the vapor amount set value b. By this loop, when the deviation c is larger than the limit value d, the limit value d becomes the input of the integrator 67, and the output of the integrator 67 continuously changes linearly. Therefore, by changing the limit value d, the rate of change of the vapor amount set value b can be changed. Further, when the deviation c becomes smaller than the limit value d, the deviation c becomes an input of the integrator 67, so that the output of the integrator 67 becomes the final target value a in the form of a first-order lag curve.

The limit value d of the upper and lower limiter 66 is formed by a function generator 68 which inputs a steam deviation value e described later. This function generator 68 is a function generator in which the x-axis is the steam deviation value e and the y-axis is the limit value d. As shown in FIG. 5A, when the steam deviation value e increases to the plus side, the upper limit is reached. The value decreases, and when the steam deviation value e increases to the negative side, the lower limit value increases. Therefore, when the steam deviation value e increases toward the plus side or the minus side, the rate of change of the set value of the steam amount decreases, and the change of the set value of the steam amount becomes gentle.

Further, an incineration amount calculator 69 is provided which calculates calories by the steam amount set value b and the set value (Hu value) of the calorific value setter 33 and calculates the required amount of incinerated waste, the output of which is estimated. The incineration amount f is output to the air amount control unit 53 and the stoker speed control unit 55.

Further, a comparator 70 is provided for detecting that the steam amount set value b becomes equal to or more than a predetermined steam amount α.
Driven by the output of 70, the stoker speed control unit described later
Based on the stoker set transport speed g of 55, the calorific value setter 33
A refuse supply speed monitor 71 for outputting the UP / DOWN signal h of the set value is provided. In the supply speed monitoring unit 71,
If the stoker set transport speed g is slower than the specified transport speed, U
The P signal is output, and if it is slower than the rated transport speed, the DOWN signal is output.

The air amount controller 53 includes a vapor amount detector 1
8. The steam amount setter 34 is connected, and as shown in FIG. 3, the set steam amount b output from the steam amount setter 34 and the detector 18
A subtractor 81 for calculating the above-mentioned vapor amount deviation e from the actual vapor amount j detected by the above is provided, and the set air amount 1 of the stoker 3 is calculated by the PID arithmetic unit 82 by this deviation e, and this PID arithmetic unit 82 The set air amount l of the stoker 3 output from the air conditioner is limited by the upper and lower limiter 83 {limit value m (described later)} and output to the blower motor drive unit 54.

The limit value m of the upper and lower limiters 83 is formed by the function generator 84 which receives the estimated incineration amount f output from the estimated incineration amount generation unit 52 as an input. This function generator 84 is a function generator in which the x-axis is the estimated incineration value f and the y-axis is the limit value m. As shown in FIG. 5B, the estimated incineration value f is the specified value β.
If it is smaller, the upper limit is limited to the minimum value, and if it is larger than the specified value β, it increases in proportion to the estimated incineration value f. The lower limit value is the number of rotations of the motor 14 at the lowest speed operation of the forced draft fan 13. When the estimated incineration value f is small, that is, in the initial stage of combustion, the air amount is limited to the minimum value, and when the estimated incineration value f becomes large, the air amount 1 corresponding to the vapor amount deviation e is set.

The blower motor driving section 54 is provided with a push blower 13
Connected to the inverter 15 of the sequencer 51, the rotation speed of the motor 14 at the lowest operating speed of the forced draft fan 13 is obtained from the start signal of the sequencer 51, and output to the inverter 15 to activate the forced draft fan 13, and the stop signal of the sequencer 51 is used. The rotation speed "0" is output to the inverter 15 and the forced draft blower 13 is stopped. When the set air amount 1 of the stoker 3 is input from the air amount control unit 53, the rotation speed of the motor 14 corresponding to the set air amount 1 is calculated and output to the inverter 15 of the motor 14.

Further, a dust layer thickness detector 17 and a dust layer thickness setting device 35 are connected to the stalker speed control unit 55, and as shown in FIG. 4, the set air amount 1 of the stoker 3 becomes a predetermined value γ or more. A comparator 91 for detecting the fact, a relay 92 excited by the output of the comparator 91, and a third setter 93 for setting the dust layer thickness to "0" are provided. With the contact point of the relay 92, the actual dust layer thickness q detected by the detector 17 and the output of the third setting device 93 are switched to form a feedback value w, which is fed from the feedback value w and the dust layer thickness setting device 35. A subtractor 94 for calculating a deviation r from the output set dust layer thickness p is provided, and the PID calculator 95 calculates a set conveying speed g of the stoker 3 based on the deviation r.
The set conveying speed g of the stoker 3 output from the computing unit 95 is limited by the upper and lower limiter 96 {limit value s (described later)} and output to the stoker motor drive unit 56.

The limit value s of the upper and lower limiter 96 is formed by the function generator 97 which receives the estimated incineration amount f output from the estimated incineration amount generation unit 52 as an input. The function generator 97 is a function generator in which the x-axis is the estimated incineration value f and the y-axis is the limit value s. As shown in FIG. 5C, the estimated incineration value f is the specified value Δ.
If it is smaller, the upper limit is limited to the minimum value, and if it is larger than the specified value Δ, it increases in proportion to the estimated incineration value f. The lower limit is the rotation speed of the motor 11 when the stalker 3 is conveyed at the lowest speed. Therefore, when the estimated incineration value f is small, that is, in the initial stage of combustion, the speed of the stoker 3 is limited to the minimum value, and when the estimated incineration value f becomes large, the deviation r of the dust layer thickness r
The transport speed is set according to.

The stalker motor drive unit 56 is connected to the inverter 12 of the stalker 3, and obtains the rotation speed of the motor 11 when the stalker 3 is conveyed at the lowest speed by the start signal of the sequencer 51, and outputs it to the inverter 12 to output it to the stalker 3. Is started, and the rotation speed “0” is output to the inverter 12 by the stop signal of the sequence unit 51 to stop the stalker 3. When the set conveying speed g of the stoker 3 is input from the stoker speed controller 55, the rotation speed of the motor 11 corresponding to the set conveying speed g is calculated and output to the inverter 12 of the motor 11.

The operation of the above configuration will be described. [Startup] When the start-up operation signal is input by the start / stop switch 31, the sequencer 51 outputs the start-up signal to the blower motor drive 54 and the stoker motor drive 56.

The blower motor drive unit 54 and the stoker motor drive unit 56 start the forced draft blower 13 and the stoker 3 at the minimum operating speed, respectively. [At start-up] Sequence section 51 inputs a "start-up" operation signal by means of start / stop start-up switch 32, and when a predetermined process is reached, a start-up control execution signal is sent to estimated incineration amount generation section 52. Output.

In the estimated incineration amount generation unit 52, the relay 62 is excited by the start-up control execution signal via the RS flip-flop 61, so that the rated steam amount set in the setter 63 is the target value of the steam amount. and the steam amount set value b continuously increases linearly by the first-order lag loop with a limiter.

A calorie calculation is performed based on the steam amount set value b and the set value (Hu value) of the calorific value setter 33 to calculate a necessary refuse incineration amount (estimated incineration amount f), and an air amount control unit.
It is output to 53 and the stoker speed controller 55.

In the air amount control unit 53, the set air amount 1 of the stoker 3 is calculated by PID control according to the steam amount set value b. In the initial combustion state at startup, the deviation e between the steam amount set value b and the actual steam amount j becomes large, and the integrator (I) is saturated, so the set air amount 1 is a value limited to the limit value m. Become. By this control, the set air amount 1 changes at a constant level in the initial stage of throwing in the dust 2, and when the dust 2 is sufficiently supplied and the generated steam amount j approaches the target steam amount, the PID control operates. To do.

In the stoker speed controller 55, P is set according to the set dust layer thickness p output from the dust layer thickness setter 35.
The set transport speed u of the stoker 3 is calculated by the ID control. In the initial combustion state at startup, the actual waste layer thickness p is "
Since 0 "is set, the integrator (I) is saturated, and the stoker set conveyance speed g becomes a value limited to the limit value s. By this control, the conveyance speed of the dust 2 is increased in the initial stage when the dust 2 is thrown in. Changes at a constant speed, the dust 2 is sufficiently supplied, and when the amount of combustion air reaches a layer thickness measurable amount, the relay 92 is excited, and the feedback value w of the dust layer thickness becomes normal. It indicates the value q, and the PID control operates.

In the initial stage of combustion, when the steam deviation value e of the air quantity control unit 53 is not eliminated, that is, when the steam does not occur as planned, the estimated incineration amount f is significantly different from the actual waste 2. That is, it is determined that the heat generation amount (Hu value) is not appropriate, and the correction value is made to slow down the rising rate of the steam amount set value b by narrowing down the limit value d of the upper and lower limiter 66.

When the steam amount set value b becomes equal to or larger than the predetermined steam amount α, the supply speed monitoring unit 71 is driven, and the set value is set to the calorific value setter 33 based on the stoker set conveying speed g of the stoker speed control unit 55. The UP / DOWN signal is output, and the set value (Hu value) of the heat generation amount setter 33 is appropriately corrected. [At the time of shutdown] When the sequence unit 51 inputs a "fall" operation signal by the startup / shutdown activation switch 32, it outputs a shutdown control execution signal to the estimated incineration amount generation unit 52.

In the estimated incineration amount generation unit 52, the RS flip-flop 61 is reset by the execution signal of the fall control and the relay 62 becomes non-excited, and the steam amount "0" set in the setter 64 becomes the steam amount. The target value a is set to, and the steam amount set value b continuously decreases linearly from the rated steam amount by the first-order lag loop with a limiter.

A calorie calculation is performed based on the steam amount set value b and the set value (Hu value) of the calorific value setter 33 to calculate a necessary refuse incineration amount (estimated incineration amount f), and an air amount control unit.
It is output to 53 and the stoker speed controller 55.

In the air amount controller 53, the set air amount 1 of the stoker 3 is calculated by PID control according to the descending steam amount set value b. The deviation e between the set steam amount b and the actual steam amount j is small in the falling combustion initial state, and the air amount is gradually reduced by the PID control, and the set air amount l is limited in the falling combustion final state. The value is limited to the value (lower limit) m. By this control, the forced draft blower 13 is operated at the minimum operating speed in the final stage of combustion of the shut-down,
The air volume remains constant.

In the stalker speed controller 55, P is set according to the set dust layer thickness p output from the dust layer thickness setting device 35.
The set transport speed u of the stoker 3 is calculated by the ID control. In the initial combustion state of falling, the deviation r between the set dust layer thickness p and the actual dust layer thickness p is small, and the conveyance speed of the stoker 3 is gradually reduced by the PID control. Is cut off, the set conveying speed g becomes a value limited to the limit value (lower limit value) s. By this control, in the final combustion state of falling, the stalker 3 is operated at the minimum operation speed, and the transfer speed of the dust 2 changes at a constant speed. [Stop] When the start / stop switch 31 inputs a "stop" operation signal, the sequence section 51 outputs a stop signal to the blower motor drive section 54 and the stoker motor drive section 56.

The blower motor drive unit 54 and the stoker motor drive unit 56 stop the pushing blower 13 and the stoker 3, respectively. As described above, by limiting the feed air amount to the stoker 3 and the dust conveying speed of the stoker 3 by the estimated incineration amount value based on the continuously generated target steam amount, an excessive control loop of the conventional control loop is provided. The operation can be eliminated, the initial combustion curve can be made smooth and optimal,
When the combustion further progresses, the control units 53 and 55 can control the feed air amount and the refuse transport speed without the limitation by the estimated incineration amount value, and perform the combustion in accordance with the set steam amount b (estimated incineration amount f). be able to.

Even if there is a difference in the composition of the waste 2, by delaying the change of the steam amount set value b in the combustion transition period,
It is possible to control according to changes in the quality of waste, and to perform optimal combustion.

When the amount of steam reaches a predetermined value, the stoker 3
The estimated heat generation amount Hu of the dust is corrected by the set transport speed g of 1. Therefore, the estimated incineration amount f itself is also corrected, and stable rated operation can be performed.

Further, since the control structure of the control device 21 is simple, the reliability is increased and the number of parameters to be adjusted is reduced, so that the adjustment time can be shortened and the cost can be reduced.

[0048]

As described above, according to the first aspect of the present invention, the feed air amount to the stoker and the dust conveying speed of the stoker are limited by the estimated incineration amount value based on the continuously generated target steam amount. By doing so, the combustion in the combustion transition period can be optimized.

According to the second aspect of the invention, when the amount of steam generated changes due to a change in the quality of dust, the predetermined rate of change of the steam generation target value is corrected in accordance with the change in the amount of waste, thereby changing the quality of dust. It is possible to control in accordance with the above, and it is possible to perform optimum combustion.

According to the third aspect of the present invention, when the amount of steam becomes a predetermined amount, the estimated heat generation amount of the dust is corrected by the conveying speed of the stoker, and therefore the estimated incineration amount itself is also corrected and stable rated operation is performed. Can be moved to.

[Brief description of drawings]

FIG. 1 is a control configuration diagram of a refuse incinerator according to an embodiment of the present invention.

FIG. 2 is a block diagram of an estimated incineration amount generation unit of the control device for the refuse incinerator.

FIG. 3 is a block diagram of an air amount control unit of the control device for the refuse incinerator.

FIG. 4 is a block diagram of a stalker speed control unit of the control device for the refuse incinerator.

FIG. 5 is a diagram showing a function of a function generator of the control device for the refuse incinerator.

FIG. 6 is a plan view of a setting device of the control device for the refuse incinerator.

FIG. 7 is a schematic configuration diagram of the refuse incinerator.

[Explanation of symbols] 1 Waste incineration boiler 2 Waste 3 Stalker 4 Air 5 Combustion gas 6 Superheater 11, 14 Motor 12, 15 Inverter 13 Indented blower 17 Waste layer thickness detector 18 Steam amount detector 21 Controller 22 Control panel 31 Start / stop switch 32 Start / stop start switch 33 Heat generation amount setter 34 Steam amount setter 35 Waste layer thickness setter 51 Sequence part 52 Estimated incineration amount generation part 53 Air amount control part 54 Blower motor drive part 55 Stalker speed Control unit 56 Stalker motor drive unit

Claims (3)

[Claims] 1. Garbage is continuously conveyed by a stoker,
A method for controlling a refuse incineration boiler in which air is sent from below the stoker to incinerate, and steam is generated, wherein the target value of the amount of steam generated is continuously generated at a predetermined change rate, and the target value of steam generation is An estimated incineration amount value is formed by the estimated heat generation amount of the waste, and the control value of the amount of air sent to the stoker that is formed based on the steam generation target value is limited by the estimated incineration amount value, and the waste layer thickness A method for controlling a refuse incineration boiler, characterized in that a control value of a refuse conveying speed of the stoker formed based on a set value is limited by the estimated incineration amount value. 2. The method for controlling a refuse incineration boiler according to claim 1, wherein the predetermined change rate of the steam generation target value is corrected by the deviation between the steam generation target value and the actual steam generation amount. 3. The method for controlling a refuse incineration boiler according to claim 1, wherein the estimated heat generation amount of the waste is corrected by the waste conveying speed of the stoker.