JP3372159B2 - Temperature control method and device for incinerator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an incinerator temperature control method for incinerating incineration materials such as municipal solid waste and industrial waste, and an improvement in the apparatus, and more particularly to a stable combustion of the incineration materials. The present invention belongs to the technical field of a temperature control method for an incinerator and a device for controlling the temperature.

[0002]

2. Description of the Related Art In recent years, a fluidized bed type incinerator has been widely used for incineration of incineration materials such as municipal solid waste and industrial wastes from the viewpoint of excellent incineration efficiency. In the case of a fluidized bed incinerator, it is preferable that stable burning of the incineration object can be continued. Therefore, it is considered that the furnace temperature is constant in a stable combustion state of the incineration object, and a method for controlling the stable combustion of the incineration object by constant control of the furnace temperature has been developed. The outline of the method according to the conventional example 1 will be described below. This is a control method in which the furnace temperature is a controlled variable and the supply amount of incineration is a manipulated variable. Specifically, it is measured at time i. Deviation Δ between the in-furnace temperature T _i and the preset target temperature T _r
T _i (= The supply amount u _i of the incineration object is calculated from T _i −T _r ).
u _i = K _p ΔT _i + K _i ΣT _i + K _d (T _i −T _i−1 ) /
The waste supply device, which is an incineration object supply device, is controlled so as to supply the incineration material in the incineration furnace by the calculated amount u _i as well as the Δt equation. Note that K in the above formula
_p is a proportional gain, K _i is an integral gain, K _d is a differential gain, and Δt is a data sampling time. That is, K
_p, K _i, and set based on the gain K _d of the operational data and control specifications for each sampling time Delta] t, and calculates the supply amount u _i of the incinerated, the amount u _i obtained by the calculation The incinerator is put into an incinerator.

The temperature control method according to the above-mentioned conventional example 1 is useful as it is because the temperature in the furnace can be controlled to be constant when the temperature fluctuation is gentle, but a sudden excess supply of the incineration material is required. When a rapid temperature change occurs due to such reasons, the control response is poor because the delay time of the furnace temperature measurement is not taken into consideration, and it is difficult to keep the furnace temperature constant. By the way, a device capable of coping with a rapid temperature change due to a sudden excessive supply of the incineration object is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-170715. Hereinafter, the fluidized bed type incinerator device according to Conventional Example 2 will be described with reference to FIG. 3 which is a schematic overall view and FIG. 4 which is a configuration diagram of a control system. Description will be given with the same reference numerals.

That is, the reference numeral 1 shown in FIG. 3 is a furnace body, and in the furnace 1a of the furnace body 1, a fluid medium S such as sand which is kept at a high temperature by the combustion of the incineration object G is stored. There is. The furnace body 1
Is a charging port 2 for charging the incineration object G on the fluidized medium S,
An exhaust port 3 for discharging the incombustible substance G _a in the incinerated substance G together with the fluidized medium S and an exhaust port 4 for discharging the exhaust gas after combustion are provided. A screw conveyor 6 and a hopper 7 for feeding an incineration object G to the screw conveyor 6 via a charging chute 5 are connected to the charging port 2. Primary air supplied from a primary air supply mechanism 9 provided outside the furnace body 1 is jetted to the bottom of the furnace 1a,
A plurality of air diffusers 8 having a large number of nozzles (not shown) for fluidizing the fluidized medium S and the incinerated material G to dry, pyrolyze and burn the incinerated material G are arranged in parallel in a state of being buried in the fluidized media S. ing. The primary air supply mechanism 9 includes a primary air blower 10, a damper 11 for adjusting the flow rate of the primary air blown from the primary air blower 10, and a primary air flow rate transmitter 1.
2 and. In addition, secondary air supplied from a secondary air supply mechanism 14 provided on the outside of the furnace body 1 is ejected to burn a secondary gas for combustible gas generated from the incineration object G for secondary combustion. A secondary air supply port 13 is provided. The secondary air supply mechanism 14, like the primary air supply mechanism 9, has a secondary air blower 15, a damper 16 for adjusting the flow rate of the secondary air blown from the secondary air blower 15, and a secondary air blower 15. It is composed of an air flow rate transmitter 17.

At the exhaust port 4, a dust settling chamber 21 for settling and removing dust in the exhaust gas, an exhaust heat boiler 22 for recovering heat of the exhaust gas, and dust in the exhaust gas are provided. An exhaust passage 19 having an electrostatic precipitator 23 for electrically adsorbing and removing the chimney 1 through an induced air exhauster 20.
It communicates with 8. Then, wherein the inlet of the electrostatic precipitator 23, O ₂ O ₂ concentration analyzer 24 for analyzing the concentration, also the pressure inside the furnace for measuring the change in pressure in the furnace 1a in the furnace body 1 in the exhaust gas A measuring device 25 is installed, and based on the measured values of the O ₂ concentration analyzer 24 and the furnace pressure measuring device 25, a secondary air control system 2 shown in FIG.
6, the supply amount of secondary air required for secondary combustion, that is, the supply amount of secondary air by the secondary air supply mechanism 14 is appropriately controlled according to the state of primary combustion.

In the secondary air control system 26, a total combustion air amount calculator 27 for calculating the total amount of air required for primary and secondary combustion is supplied from the primary air supply mechanism 9 and the secondary air supply mechanism 14. The air amount is provisionally set in advance, and the set value and the signal of the primary air amount transmitter 12 are input to the secondary air flow rate setting calculator 28, where the total air amount is changed to the signal of the primary air amount transmitter 12. A value obtained by subtracting the primary air amount based on this is set as the secondary air supply amount, and is input to the secondary air flow rate controller 29. The secondary air flow rate controller 29 controls the supply amount of the secondary air from the secondary air supply mechanism 14 so that the flow rate signal of the secondary air sent from the secondary air flow rate transmitter 17 always becomes a set value. . Further, the O ₂ concentration in the exhaust gas generated in the furnace 1a is analyzed by the O ₂ concentration analyzer 24 provided at the inlet of the electrostatic precipitator 23, and the appropriate O ₂ preset is set.
_The signal output from the O ₂ concentration controller 30 so that the concentration becomes ₂ is sent to the correction calculator 31, where the secondary air supply setting signal sent from the secondary air flow rate setting calculator 28 is corrected, and thereafter, To the secondary air flow controller 29, and the secondary air flow controller 29 controls the amount of secondary air supplied from the secondary air supply mechanism 14.

Further, the signal of the in-furnace pressure measured by the in-furnace pressure setting device 25 is sent to the averaging arithmetic unit 32, subjected to moving average processing, and then sent to the signal processing arithmetic unit 33. The signal processing calculator 33 compares the averaged signal with the signal of the furnace pressure sent from the furnace pressure setter 25 to generate a secondary air flow rate correction signal according to the magnitude of the deviation, The setting signal sent to the secondary air flow rate controller by the signal is corrected by the correction calculator 31 so that the secondary air flow rate is controlled to an appropriate amount. In addition, the code | symbol 35 shown in FIG. 4 is a primary air flow rate control apparatus, and the code | symbol 36 is a secondary air flow rate control apparatus.

[0008]

As described above, the fluidized bed type incinerator apparatus according to the conventional example 2 detects a rapid change in combustion of the incineration object from the pressure value in the furnace, and thereby the secondary air is generated. A flow rate correction signal is generated to control the flow rate of the secondary air to be appropriate. Therefore, it is useful for complete combustion of the combustible gas generated in the furnace. However, although the amount of harmful substances generated can be suppressed by completely burning the combustible gas, the temperature inside the furnace cannot always be maintained at a constant level, and the wear of the refractory due to temperature fluctuations inside the furnace is large and the fluidized bed There was a problem to be solved economically that the life of the incinerator is shortened and the maintenance cost of the fluidized bed incinerator increases. In other words, it is possible to keep the in-furnace temperature of the fluidized bed incinerator constant by stably burning the incineration object,
It is desirable for suppressing the generation of harmful substances and extending the life of fluidized bed incinerators.

Accordingly, the present invention provides a temperature control method for an incinerator and a device therefor, which makes it possible to keep the temperature inside the fluidized bed incinerator at a constant level by stably burning the incineration object. To aim.

[0010]

In order to solve the above problems, the gist of the temperature control method for an incinerator according to claim 1 of the present invention is to detect the pressure inside the incinerator and to detect the detected inside The moving average value of the in-furnace pressure is obtained from the pressure data and the past data of the in-furnace pressure, and the moving average value is compared with the preset threshold value. Occasionally, the change amount of the furnace temperature after a preset time is predicted from the relational expression between the change of the furnace pressure and the change of the furnace temperature and the pressure data of the furnace, and the target temperature and the change amount of the temperature of the furnace While controlling the supply amount of the incineration object by using the difference correction temperature as a new target temperature, control the supply amount of the incineration object by setting the initial target temperature as a target when the moving average value is less than the threshold value. Characterize.

The gist of the temperature control method for an incinerator according to claim 2 of the present invention is, in the temperature control method for an incinerator according to claim 1, the relationship between a change in the furnace pressure and a change in the furnace temperature. It is characterized by predicting the temperature change in the furnace by expressing the equation as a transfer function.

The structure of the temperature control device for an incinerator according to claim 3 of the present invention comprises a pressure / temperature detection device 11 for detecting the in-furnace pressure and the in-furnace temperature of the incinerator, and this pressure / temperature detector 1.
Moving average value calculation device 12 for calculating a moving average value from the in-furnace pressure data detected in 1 and the past data of the in-furnace pressure
And a coefficient storage device 15 that stores a predetermined coefficient of a transfer function that represents the relationship between the change in the furnace pressure and the change in the furnace temperature, the moving average value, and a preset threshold value. When the moving average value is greater than or equal to the threshold value, the relational expression between the change in the furnace pressure and the change in the furnace temperature, the furnace pressure data, and the coefficient of the transfer function were used to set in advance. Calculate the amount of temperature change in the furnace after time,
A target temperature calculation device 13 that calculates a correction temperature of the difference between the target temperature and the temperature change amount in the furnace, and a supply amount of the incineration object that is calculated from the correction temperature, and the incineration amount of the amount that is calculated is calculated. While controlling the incinerator supply device 4 to supply to the incinerator, when the moving average value is less than the threshold value, the temperature of the in-furnace temperature data detected by the pressure / temperature detection device 11 and the target temperature The difference is calculated, the supply amount of the incineration object is calculated from this temperature difference, and the control amount calculation is performed to control the incineration object supply device 4 so as to supply the incineration object of the amount obtained by the calculation to the incinerator. And a device (14).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A temperature control device for an incinerator according to an embodiment of the present invention will be described below with reference to FIG. 1 which is a schematic configuration explanatory view of a fluidized bed incinerator and FIG. 2 which is a target temperature calculation flow chart thereof. It will be explained with reference to and. However, since the structure of the fluidized bed incinerator according to the embodiment of the present invention is almost the same as that of the conventional example, the structure is not described in the outline, and the structure of the temperature control device is mainly described. . That is, reference numeral 1 shown in FIG. 1 denotes a furnace body of a fluidized bed incinerator, in which the fluid medium S made of silica sand or the like stored in the bottom of the furnace 1a A waste input port 2 for inputting the incinerated material is provided, and this waste input port 2
An incineration object such as dust is supplied from the garbage supply device 4 which is an incineration material supply device through the chute 3. Although not shown, an exhaust port for discharging incombustible substances in the incinerated material together with the fluidized medium S and an exhaust port for discharging exhaust gas after combustion are provided, and primary air and secondary air are provided in the furnace 1a. A primary and secondary air supply mechanism for blowing air is also provided. The dust supply device 4 of such a fluidized bed incinerator is controlled by a temperature control device 10 having a configuration described later so as to adjust the supply amount of the incineration object to be put into the furnace 1a.

The temperature control device 10 is constructed as shown in FIG. That is, the pressure signal from the pressure sensor P _s provided on the side of the furnace body 1 and the pressure signal from the temperature sensor T _s provided on the top of the furnace body 1 are received to determine the furnace pressure and the furnace temperature. A pressure / temperature detecting device 11 for detecting is provided. The in-furnace pressure data detected by the pressure / temperature detecting device 11 is sent to a moving average value calculating device 12 which calculates the moving average value P ′. The moving average value P ′ calculated by the moving average value calculating device 12 and a coefficient storage device 15 for storing a coefficient previously obtained from a transfer function obtained from the relationship between the pressure change and the temperature change in the furnace. The coefficient signal is input to the target temperature calculation device 13 to which the target temperature T _r is input.

The target temperature calculating device 13 compares the moving average value P'calculated by the pressure calculating device 12 with a preset threshold value P ", and the moving average value P'is a threshold value. When it is equal to or more than P ″, it is determined that the initialization target temperature T _r needs to be corrected, the temperature change amount is calculated using the coefficient of the transfer function stored in the storage device 15, and the target temperature Tr is calculated.
Is corrected and a new target temperature T _r ′ is output. When the moving average value P ′ is less than the threshold value P ″, the target temperature T _r
It is determined that the correction of No. is unnecessary, and the initial target temperature T _r is output as it is. Then, the target temperature new target temperature is corrected from the arithmetic unit 13 T _r 'or initial target temperature T _r is input from the pressure and temperature sensing device 11 to the control calculation unit 14 furnace temperature is input It has become so. That is, the control amount calculation device 14 is configured so that the target temperature T _r ′, T input from the target temperature calculation device 13 is input.
_{From r} and the in-furnace temperature data input from the pressure / temperature detector 11, the supply amount u _i of the incineration object is calculated, and the incineration amount of the calculated amount is supplied to the in-furnace 1a. As described above, the refuse supply device 4 is controlled.

Next, based on FIG. 2, the temperature control device 10
The operation of the pressure / temperature detection device 1 will be described in step 1 via the pressure sensor P _s and the temperature sensor T _s.
By 1, the in-furnace pressure data P _i and the in-furnace temperature data T _i in the in-furnace 1a of the furnace body 1 at time i are sequentially detected, and the routine proceeds to step 2.

In step 2, in the moving average value computing device 12, the in-furnace pressure data P _i and the past pressure data P _k (k = i−1,
i−2, ..., In), and the weighting coefficient C _i (i = 0, 1, 2, ..., N) set in advance, the moving average value P ′ of the pressure in the furnace is given by the following equation. Based on the calculation, the process proceeds to step 3. P ′ = C ₀ * P _i + C ₁ * P _i-1 ‥‥ ＋ C _n * P _in ‥‥‥‥

In step 3, the target temperature calculating device 13 compares the moving average value P'input from the calculating device 12 with a predetermined threshold value P ". When the value P ′ is less than the threshold value P ″, it is determined that no sudden change in the furnace temperature has occurred, and the routine proceeds to step 5.

In step 5, the controlled variable computing device 14
The temperature T in the furnace obtained by the pressure / temperature detection device 11
_i and the temperature deviation Δ between this furnace temperature T _i and the target temperature T _r
The supply amount u _i of the incineration product is calculated from T _i and the following expression, and the amount of the incineration product obtained by the calculation is supplied to the fluidized bed incinerator, and the same as in Conventional Example 1 Target temperature T
_The waste supply device 4 is controlled with _r as a target. u _i = K _p ΔT _i + K _i ΣT _i + K _d (T _i −T _i-1 ) / Δt ..... where K _p is a proportional gain, K _i is an integral gain, and K _d is a differential gain. , Δt are data sampling times, which are exactly the same as those in the conventional example 1.

On the other hand, in step 3, as a result of the magnitude comparison between the moving average value P'input from the arithmetic unit 12 and a predetermined threshold value P ", the moving average value P'is the threshold value P". In the case of Yes as described above, it is determined that the in-furnace pressure has rapidly changed due to the temperature rise due to the excessive supply of the incineration object, and the process proceeds to step 4.

In step 4, the target temperature computing device 1
In 3, the calculation for obtaining the temperature change amount for making the furnace temperature the target temperature is performed. In order to calculate this temperature change amount, first, the correspondence relationship between the change ΔP _i in the furnace pressure and the change ΔT _{1 in the} furnace temperature is set as an impulse model (transfer function) represented by the following n-th equation. , Its coefficients h ₁ , h ₂ ,
.., h _n is obtained from the operation data and stored in the storage device 15.

[Equation 1] In addition, l is a delay time of temperature measurement in the pressure / temperature detection device 11. Next, while the moving average value P'is equal to or larger than the threshold value P ", the difference (P'-P") between the moving average value P'and the threshold value P "is successively calculated.
As the deviation ΔP _{i at the} time i, a temperature deviation ΔT ₁ which is a temperature change amount predicted to occur one hour later is calculated by the following equation using the past value of the pressure deviation and the coefficient of the impulse model (transfer function). Desired.

[Equation 2] That is, the temperature deviation ΔT ₁ obtained from the above equation is considered to be the predicted value of the temperature deviation that will occur one hour after the delay time l of the temperature measurement in the pressure / temperature detection device 11 is set to 0. It is what is done. Then, the corrected temperature T _r ′ (= T _r −ΔT ₁ ) obtained by subtracting the temperature deviation ΔT ₁ obtained by the above equation from the target temperature T _r is output as a new target temperature, and the process proceeds to step 5.

[0022] In step 5, 'operation of the feed amount u _i of the incinerated is performed based on a new target temperature T _r' target temperature T _r dust feeder 4 is controlled as a target,
The fluidized bed type incinerator is supplied with the amount of incineration material u _i obtained by calculation. In this case, the supply amount u of the incineration object is calculated from the temperature deviation ΔT _i (= T _i −T _r ′) between the furnace temperature T _i measured at time i and the new target temperature T _r ′.
_i is u _i = K _p ΔT _i + K _i ΣT _i + K _d (T _i −T
_i-1 ) / [Delta] t.

The above calculation in step 4 is Δ
This is performed from the time when T ₁ <0 (P ′ <P ″) until n sampling times have elapsed, and when the temperature deviation that is the temperature change amount for reaching the target temperature becomes 0, the target temperature is set to Tr in step 5. Control of the normal supply amount u _i of the incineration object, that is, u _i = K _p ΔT _i + K _i ΣT _i + K as in the first conventional example.
The supply amount u _i of the incineration object is calculated by an expression represented by _d (T _i −T _i−1 ) / Δt, the waste supply device 4 is controlled with the initial target temperature T _r as a target, and the fluidized bed type is used. The incinerator is supplied with the amount u _i of the incinerated material obtained by calculation.

As described above, the rapid fluctuation occurring in the furnace temperature is detected from the furnace pressure which changes more rapidly than the temperature change, and the supply amount of the incineration object is adjusted, so that the temperature control is promptly responsive. Is extremely excellent. In addition, since a rapid change in the furnace temperature is predicted and controlled in advance, it can greatly contribute to maintaining the furnace temperature at a constant level, and suppresses wear of refractory due to temperature fluctuations in the furnace It has a great effect on prolonging the life and reducing the maintenance cost of the fluidized bed incinerator. In the above, the temperature control device of the fluidized bed incinerator has been described as an example, but since the technical idea of the present invention can be applied to incinerators of other embodiments, the above-mentioned embodiment is used. However, the scope of the technical idea of the present invention is not limited thereto.

[0025]

As described above in detail, according to the present invention according to claims 1 to 3, a rapid fluctuation occurring in the temperature inside the furnace is detected from the pressure inside the furnace which changes more rapidly than the temperature change. In addition, since the supply rate of the incineration material is adjusted, the responsiveness of temperature control is extremely excellent, and abrupt changes in the furnace temperature are predicted and controlled in advance, which greatly contributes to maintaining the furnace temperature constant. Therefore, it is possible to expect a great effect on prolonging the life of the fluidized bed type incinerator by suppressing the wear of the refractory due to the temperature change in the furnace and reducing the maintenance cost of the fluidized bed type incinerator.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory diagram of a temperature control device for a fluidized bed incinerator according to an embodiment of the present invention.

FIG. 2 is a target temperature calculation flow chart of the temperature control device for the fluidized bed incinerator according to the embodiment of the present invention.

FIG. 3 is a schematic overall view of a fluidized bed incinerator device according to Conventional Example 2.

FIG. 4 is a configuration diagram of a control system of a fluidized bed incinerator apparatus according to Conventional Example 2.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Furnace body, 1a ... Furnace, 2 ... Garbage input port, 3 ... Chute, 4 ... Garbage supply device, 10 ... Temperature control device, 11 ... Pressure / temperature detection device, 12 ... Moving average value calculation device, 13 ...
Target temperature calculating unit, 14 ... control amount calculation unit, 15 ... coefficient storage unit, S ... flowing medium, P '... moving average, P "... threshold, P _s ... pressure sensor, T _s ... temperature sensor.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuyuki Tomokichi 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Kobe Steel Works, Ltd. Kobe Research Institute (72) Inventor Akira Kitamura Nishi-ku, Kobe-shi, Hyogo Takatsukadai 1-5-5 Kobe Steel, Ltd., Kobe Research Institute (56) Reference JP-A-3-170715 (JP, A) JP-A-3-168513 (JP, A) JP-A-6 -235511 (JP, A) JP-A-8-219429 (JP, A) JP-A-5-87322 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F23G 5/50

Claims (3)

(57) [Claims] 1. The in-furnace pressure of the incinerator is detected, a moving average value of the in-furnace pressure is obtained from the detected in-furnace pressure data and past data of the in-furnace pressure, and this moving average value is preset. When comparing the magnitude with the threshold value, when this moving average value is equal to or greater than the threshold value, the relational expression between the change in the furnace pressure and the change in the furnace temperature While predicting the furnace temperature change amount and controlling the supply amount of the incineration object with the correction temperature of the difference between the target temperature and the furnace temperature change amount as a new target temperature, this moving average value is less than the threshold value. In the case of, the temperature control method of the incinerator is characterized by controlling the supply amount of the incineration target with the initial target temperature as a target. 2. The incinerator temperature change amount is predicted by expressing a relational expression of a change in the furnace pressure and a change in the furnace temperature by a transfer function. Temperature control method. 3. A pressure / temperature detection device 11 for detecting the pressure and temperature inside the furnace of the incinerator, and this pressure / temperature detector 1.
Moving average value calculation device 12 for calculating a moving average value from the in-furnace pressure data detected in 1 and the past data of the in-furnace pressure
And a coefficient storage device 15 that stores a predetermined coefficient of a transfer function that represents the relationship between the change in the furnace pressure and the change in the furnace temperature, the moving average value, and a preset threshold value. When the moving average value is greater than or equal to the threshold value, the relational expression between the change in the furnace pressure and the change in the furnace temperature, the furnace pressure data, and the coefficient of the transfer function were used to set in advance. Calculate the amount of temperature change in the furnace after time,
A target temperature calculation device 13 that calculates a correction temperature of the difference between the target temperature and the temperature change amount in the furnace, and a supply amount of the incineration object that is calculated from the correction temperature, and the incineration amount of the amount that is calculated is calculated. While controlling the incinerator supply device 4 to supply to the incinerator, when the moving average value is less than the threshold value, the temperature of the in-furnace temperature data detected by the pressure / temperature detection device 11 and the target temperature The difference is calculated, the supply amount of the incineration object is calculated from this temperature difference, and the control amount calculation is performed to control the incineration object supply device 4 so as to supply the incineration object of the amount obtained by the calculation to the incinerator. A device 14 for controlling the temperature of an incinerator.