JPS58195707A - Combustion control method for refuse incinerator - Google Patents

Abstract

PURPOSE:To perform a stable combustion of refuse, by a method wherein a heat quantity produced in a refuse incinerator is detected, and a distribution of a feed flow rate in a drying range, a combustion range, and a post-combustion range is changed and a refuse feed flow rate is adjusted so that the generated heat quantity is kept constant. CONSTITUTION:In case a flow rate 10 of steam produced in a boiler 8 located in a flue of an incinerator is increased from a set flow rate 55, a signal from a regulator 23 consisting of a PID computing element is inputted to computing elements 25-27 togetherwith a signal from an air flow rate set circuit 60 through a distributing circuit 56. Openings of dampers 43 and 44 are reduced by means of the outputs of the computing elements 25 and 26, a flow rate of the air to a drying range A1 and a combustion range A2 is decreased, and simultaneously, according to the output of the computer 27, an opening of a damper 45 is increased to increase a flow rate of the air to a post-combustion range A3. Through a refuse feed flow rate controller 20 and a fluidized bed speed controller 21 which are actuated by means of computing elements 31 and 32 through a regulator 29, a pusher 4 and fluidized beds 5-6 are adjusted into the reduction in a flow rate and deceleration of a speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the combustion state during incineration in an incinerator equipped with a stoker or moving bed for incinerating solid waste.

In recent years, garbage has become more and more popular than simply incinerated waste, as exemplified by waste power generation, in which a boiler is installed in a garbage incinerator, the heat generated during garbage incineration is recovered, and the generated steam is used to generate electricity. Waste incineration facilities are becoming more resource- and energy-saving, and waste incineration facilities are now becoming more resource- and energy-saving, to the point where waste can be used as fuel to generate added value. In order to increase the added value of waste as a fuel, it is necessary to stabilize the amount of steam generated, that is, to stabilize the thermal output of the incinerator, thereby increasing the efficiency of steam utilization, as seen in the equalization of the amount of power generated by waste power generation. Improvement is essential. The various performances required for automatic combustion control of such incinerators have become much more advanced than those of conventional incinerators. That is, there is a need for an automatic combustion control method for an incinerator that can achieve stable heat output at all times while saving labor, completely incinerating waste, and reducing harmful gases such as NOx in exhaust gas.

In view of such social conditions, the present invention provides a combustion control method for a garbage incinerator that realizes stable combustion of garbage, typified by the improvement of additional siding lines that use garbage as fuel by supplying stable thermal output. It is in.

FIG. 1 is an overall system diagram of an embodiment of the present invention. Garbage is fed into the garbage incinerator 1 via a hopper 3 from a garbage supply crane 2. The garbage in the hopper 3 is dropped into the garbage incinerator 1 by a garbage supply busher 4. Garbage incinerator 1 has a discharge port 37f11 from the garbage supply bushing 4 side.
! I [Successively and sequentially, moving beds 5, 6.7 are arranged corresponding to the drying zone A1, the combustion zone A2 and the after-combustion zone A3. The garbage F that has fallen from the garbage supply busher 4 onto the moving bed 5 is dried by the air supplied from below from the moving bed 5, is moved to the moving bed 6, where it is burned, and is further transferred to the moving bed 7.
After that, it is discharged from the discharge port 37 as residual ash. The high-temperature gas generated by combustion undergoes heat exchange by the boiler 8, and is then discharged to the outside.

It will be done. Steam from the boiler 8 is supplied to one cylinder via a conduit 38 to generate electricity. Conduit 385・,
- A detector 9 interposed in detects the steam flow rate.

-, .

The pipes 40, 41, 42 are equipped with a damper 4 for controlling the lid.
3, 44, and 45 respectively. A detector 46 is provided on the downstream side of the conduit 40 to detect the air flow rate. Controller 15 responds to a signal via line 12 to
The opening degree of the damper 43 is detected by the flow M
is controlled to match the flow rate represented by the signal provided via line 12. A flow rate detector 48 and a regulator 16 are provided in association with the damper 44 . damper 45
A flow rate detector 50 and a controller 17 are provided in connection with the flow rate detector 50 and the controller 17. The regulators 16, 17 are each supplied with a signal via lines 13 and 14. Thus this line 13.1
The opening degrees of the dampers 44 and 45 are controlled so that the air flow rate corresponds to the information from the dampers 44 and 45.

Moving floor 5, 6. ．． 7 moves j! in response to the signal from line 19! □・) The speed of the moving bed and the moving speed of the garbage to be burned are controlled by the constancy control device 21. A waste supply flow rate control device 20 responsive to signals from the line "□'" controls the reciprocating speed of the waste supply busher 4 to control the waste supply flow rate.

The control device 11 includes a steam flow rate detector 9 via a line 10.
Faith from 1? : in response, a signal representative of the air flow rate is derived in lines 12, 13, 14, and a signal representative of the moving speed of the moving bed 5, 6.7 is derived via line 19, and a signal representative of the movement speed of the moving bed 5, 6.7 is derived via line 18. Derive a signal representing the flow rate.

First, the principle of the present invention will be explained.

The heat generated per unit time in a waste incinerator IK is generally expressed by the following formula.

Q-Kl ・ Hu-GR- (凰) Where, Q is the amount of heat generated per unit time, Hu is the amount of heat generated per unit weight of garbage, GR is the incineration rate of garbage per unit time, Kl is a coefficient determined by combustion efficiency, etc.

In the first equation, in order to keep the amount of heat generated Q constant, it is necessary to manipulate the amount of heat Hu or the incineration rate GM. Here, the chemical and physical properties of waste as a fuel are non-uniform, and the heat value 1itHu of the waste supplied into the waste incinerator l constantly fluctuates. Therefore, the calorific value H
It is practically impossible to control u, and the incineration rate GRtt-
It will be operated. It is difficult to perform a constant supply operation of garbage into the garbage incinerator 1, and fluctuations in the amount of garbage supplied to the garbage incinerator 1 are difficult to eliminate. Even if fixed-quantity supply were realized, the drying time from drying to ignition of the waste supplied to the waste incinerator 1 would vary depending on the difference in waste quality and the combustion state at that time, resulting in a decrease in the waste incineration rate. It will change.

Considering the above properties of waste as fuel, the first equation becomes the second equation.

Q- to 1・Q(uO+ΔHu)(GRO+ΔGR+ΔG
RC) - (2 + where, HuO is the average value of the calorific value per unit weight of garbage, ΔHu is the variation in the calorific value per unit weight of garbage, and GRO is the value when the garbage supplied to the garbage incinerator 1 is burned. The average value of the garbage incineration rate, ΔGR is the fluctuation in the garbage incineration rate that cannot be controlled, ΔGRC
is the operation coefficient of waste incineration rate according to the present invention.

In the second equation, the disturbance, the fluctuation in the lower heating value of dirt ΔHu
s and the fluctuation of waste incineration rate AGRKt4 and the generated heat I
It can be seen that in order to keep Q constant, it is sufficient to control the manipulated variable ΔGRC of the garbage incineration rate according to the present invention.

FIG. 2 is a modeled view of the dust increase area in the drying area A1 and the combustion area A2. Feed air A is supplied from the lower part of the moving bed 5.6 in the drying zone AI and the combustion zone A2. Supply air B is supplied from above the surface of the dust layer. The garbage in the drying area A1 is dried and solidified by the supplied air A from the lower part of the moving bed 5 and the radiant heat from the fire, and is then supplied to the combustion area A2.

The garbage in the combustion area A2 is burned by the supply amount 9LA and the supply air B.

Now, in this combustion state, if supply air A is decreased and supply air B is increased, 1. The supply air A decreases, and the inside of the a-layer K! 5 The burning speed of i, ``jF decreases・':''''
The combustion reaction takes place mainly in the surface layer. That is, the garbage incineration rate ΔGRC is reduced. Further, by reducing the supply amount 9LA to the drying area A1, there is an effect of delaying the ignition time, contributing to a reduction in the garbage incineration rate ΔGRC.

Conversely, when the supply air A is increased and the supply air B is decreased, the combustion rate inside the garbage layer increases due to the increase in the supply amount 9LA. In other words, the garbage incineration rate ΔGRC
is increased. Furthermore, increasing the amount of air A supplied to the drying area Al has the effect of speeding up the ignition time, contributing to an increase in the garbage incineration rate ΔGRC.

Supply air A and supply air B, that is, garbage incinerator l
The total amount of air supplied into the interior is determined, for example, by the following empirical formula.

GF-Human (K) Hu O+-K 3) G RO-f3
] Here, GF is the total supply air flow rate into the incinerator, λ is the excess air ratio, and K2. 3 is a coefficient determined from the average, average garbage composition. Combustion condition-1, especially excess air ratio λ, i.e. combustion 0. There is a close relationship between the concentration and the amount of harmful gas NOx generated.
□It is necessary to reduce the amount of harmful gas NOx generated by maintaining the appropriate concentration. Therefore, when combustion is active and combustion suppression is necessary, that is, when supply air A is destroyed and supply air B is increased, the combustion 0□ concentration is lower than the appropriate value, so the total supply air amount GA is increase. Conversely, when the combustion state that requires combustion acceleration declines, that is, when the supply air A
When increasing the supply air B and decreasing the supply air B, it is desirable to decrease the total supply air - GF since the furnace 02 concentration is higher than the appropriate value.

When the manipulated variable for changing the distribution amount of the supply air A, B increases the incineration rate ΔGRC from the equilibrium point, the speed of the garbage supply button 4 is gradually increased to increase the amount of garbage supplied into the incinerator. increase. Conversely, when the manipulated variable is on the side that reduces the incineration rate ΔGRC from the equilibrium point,
By gradually reducing the speed of the waste feeder 4 and reducing the waste supply flow rate to the waste incinerator 1, the average waste incineration speed 1lIGRO in the second equation is changed, and complete waste incineration and waste incineration are achieved. It becomes possible to secure the control range of the speed ΔGRC. Also, garbage incineration rate ΔGRC
In order to prevent the combustion area A2 from moving on the moving beds 5, 6.7 by increasing and decreasing When suppressing combustion, the moving bed speed is reduced, and when promoting combustion, the moving bed speed is increased. In other words, by continuously controlling the waste incineration rate ΔGRC, it is possible to continuously and accurately suppress fluctuations in the amount of heat generated due to changes in waste quality, and while achieving complete incineration of waste and reduction of generated harmful gases, it is possible to stable control can be established.

FIG. 3 is a block diagram showing a specific configuration of the control device 11. As shown in FIG. A signal from the steam flow rate detector 9 via the line 10 is input to the controller 23.

This controller 23 is supplied with a signal representing a predetermined steam system via line 22 from a setting circuit 55. The controller 23 is realized, for example, by a so-called PID calculator that performs proportional, integral, and differential calculations. Controller 2
3 calculates the deviation of the value represented by the signal from line 10.22 and derives it from line 24. The signal from line 24 is applied to one input of a calculator 25, 26, 27. A distribution circuit 5 is connected to the other human power of the computing units 25, 26, and 27.
6 through lines 57, 58, and 59, respectively. The distribution circuit 56Vc is supplied with a signal from the air flow rate setting circuit 60. The signal from air flow setting circuit 60 derives a signal representative of the air flow cap being supplied from line 39. Distribution line 56 is connected to lines 40, 41.4.
A signal for supplying air at a predetermined ratio of 2 to 1 minute is derived.

The signals derived from the controller 23 to the line 24Vc are signals a and j for making the steam flow rate in the pipe line 38 constant. The level of the signal in lines 24.57, 58.59 is proportional to the airflow l.

The computing unit 25 subtracts a value proportional to the signal via the line 24 from the reference value of the air flow rate to be supplied to the drying area AI via the line 5-7, and subtracts the value proportional to the signal via the line 12 to the controller 1 via the line 12.
5 to derive the signal. The calculator 2'i6 subtracts a value proportional to the signal via the input 24 by 1'' from the reference value of the air flow rate via the line 58 to be supplied to the combustion zone A2, and derives it to the line 13. Controller 1
Give to 6. The computing unit 27 sets the line 2 to the reference value of the empty flow rate via the line 59 to be supplied to the after-combustion area A3.
A pupil proportional to the signal via 4 is added, and the resultant signal is derived on line 14 and applied to controller 17 . The total amount of air flow to be supplied is determined according to equation 6 above. In this way, the distribution ratio of air supplied from the pipes 40.degree. 41.42 is determined by the calculator 23 and the distribution circuit 56. The total air flow rate is determined by circuit 60.

The controller 29 is realized, for example, by a so-called PID calculator that performs proportional, integral, and differential operations. This controller 29 receives the signal via line 24 and the signal from the setting device 61 via line 28, and derives a signal representing the calculation result on line 30. It is desired that the output for correction of the calculator 23 be 011111°, and therefore the setting 1.
1i61#IzG:j Ayu・"F* *-c'Ah. Yowo.
32 respectively. Outputs from the calculators 31, 32 are provided via lines 18, 19 to the waste supply flow rate controller 2o and the moving bed speed controller 21, respectively, as described above.

Assume that the steam flow rate supplied through the pipe line 38 becomes larger than the steam flow rate set in the setting circuit 55. In this case, the opening degrees of the dampers 43 and 44 are reduced by the input from the computing units 25 and 26, and the flow rate of air supplied to the drying area A1 and the combustion area A2 is reduced. In addition, the output from the calculator 27 causes the damper 45 to
The opening of the waste incinerator becomes larger, and the flow rate of air flowing from the pipe 42 into the post-combustion zone A3 increases. The supplied steam flow rate is controlled to thlk' set by the setting circuit 55. From the controller 29 to the line 30
Arithmetic units 31G, f that respond to signals via.

The pusher 4 reduces the waste supply flow rate so that the signal via the line 24 becomes the value determined by the setting device 61. In this way, the waste supply flow rate is kept at a small tji. The computing unit 32 also provides a signal to the moving bed speed control device wi21 via the line 19, thereby causing the moving beds 5, 6 to
．． The speed of No. 7 is gradually decreased so that the tuna corresponds to the value VC set in the setting circuit 61.

When the steam flow rate supplied via the pipe line 38 becomes smaller than the value set in the setting circuit 55, the computing units 25 and 26 perform an addition operation, and the computing unit 27 performs a subtraction operation. In this way, the opening degrees of the dampers 43 and 44 are increased, the opening degree of the damper 45 is decreased, and the dry area AI
The flow rate of air from the duct 40, 41 supplied to the combustion zone A2 is increased, and the flow rate of air supplied to the after-combustion zone A3 from the duct 42 is decreased. Further, the computing unit 31 reduces the reciprocating cycle of the pusher 4 to increase the waste supply flow rate, and improves the moving speed of the moving beds 5, 6.7 by the moving bed speed control device 21. In this way the steam flow rate is increased.

In the implementation described above, a detector 9 for detecting the steam flow rate was installed in the pipe line 38, and the amount of heat generated by the waste incinerator was detected by the rt Vc, and the amount of heat generated was controlled to be constant. As another embodiment of the present invention, the temperature inside the garbage incinerator 1 is detected by a thermocouple VC, and the temperature inside the furnace is controlled to be constant VCl, that is, the amount of heat generated in the garbage incinerator 1 is constant. You can do it like this.

As described above, according to the present invention, garbage is stably combusted, thereby increasing the added value of garbage as a fuel, promoting resource and energy conservation, and furthermore, by completely incinerating the garbage and causing harmful rr so that gas generation can be reduced.

[Brief explanation of drawings]

FIG. 1 is an overall system diagram of an embodiment of the present invention, FIG. 2 is a modeled cross-section of the dust layer in the drying zone A1 and the combustion zone A2VC, and FIG. 3 is a specific configuration of the control device 11. FIG. 1... Garbage incinerator, 3... Hopper, 4... Butsusha, 5.6.7... Moving bed, 8... Boiler, 9...
・Steam 9L flow wrinkle tester 815 device, 11...control device, a6,
40, 41.4, '□゛,: 2... Pipe 1, 4.3, 44.45... Damper agent Patent attorney Kei Nishi part

Claims (1)

[Claims] A garbage supply means supplies garbage to a garbage incinerator, and the garbage incinerator has movable beds each provided in a drying area, a combustion area, and an after-combustion area, and detects the amount of heat generated by the garbage incinerator. The distribution of the supply air flow rate in the drying zone, combustion zone, and after-combustion zone is changed so that the amount of heat is constant, and the garbage supply flow rate by the garbage supply means and the speed of the moving bed are adjusted based on the distribution. A combustion control method for a garbage incinerator, characterized in that: