JPS59122812A - Combustion controller of multi-stage incinerator - Google Patents

Abstract

PURPOSE:To perform efficient operation of a furnace through prevention of the supply of excessive air, by a method wherein temperature in a furnace is kept constant by controlling the amount of an object to be incinerated charged and a blast generating furnace according to the temperature in the furnace, and an air-fuel ratio is maintained in an optimum value based on the amount of the object to be incinerated charged and the heat-generating amount of sludge. CONSTITUTION:A supply quantity controller A controls the amount of an object to be incinerated supplied according to a temperature condition in a furnace 10. A controller B for oxygen concentration and combustion air flow rate corrects the reference heat- generating amount of the object to be incinerated, and computes an air-fuel ratio to regulate the quantity of a combustion air. A controller C for fuel combustion in a blast furnace controls the flow rate of the fuel and the flow rate of combustion air of the burner of the combustion stage of the incinerator to keep temperature in the incinerator in an optimum value. A controller D for the flow rate of recycling gas finds the desired value of the flow rate of recycling gas from the quantity of the object to be incinerated charged and the flow rate of combustion air to control the quantity of exhaust gas recycled. A controller E for a pressure in the incinerator holds a pressure in the incinerator in a given value by adding variation in an air quantity caused due to control of the amount of a combustion air.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a combustion control device for a multistage incinerator for incinerating materials to be incinerated such as sludge cake.

[Technical Background of the Invention] 3. Fig. 1 shows a conventional multistage incinerator combustion control device. In the figure, reference numeral 1 denotes a multi-stage incinerator, which incinerates a sludge cake introduced from the upper end thereof and then discharges it as incinerated ash from the lower end. Combustion air is supplied by forced air fan 2
is supplied from the lower end of the furnace 1 via the damper 3,
After the sludge cake is used for combustion, it is taken out from the upper end of the furnace by the exhaust gas fan 4 and discharged through the exhaust gas treatment device 5. Then, the temperature inside the furnace is detected by a temperature detector 6 such as a thermocouple, and only a high level detection signal is selected by a selector 7 and given to a temperature indicating controller (TIC) 8. Then, the temperature indicating controller 8 calculates the amount of deviation from the set temperature, outputs a correction signal to reduce the deviation to zero, and provides it to the air flow rate indicating controller (FIC) 9. This controller 9
Now, the detection signal of the differential pressure type flowmeter 10 and the correction signal are compared and calculated to determine the optimum air amount, and an opening adjustment signal is given to Danno (-3).From this, the valve opening of the damper 3 is adjusted. The optimum amount of air is supplied to the furnace 1.

[Problems in the Background Art] Such conventional combustion control devices only control the amount of combustion air based on the temperature measurement pressure in the furnace. If the situation is not properly grasped, for example, if the temperature sensor 6 is installed in a position where it is exposed to direct flame and may measure high temperature, the air volume control may become inaccurate. ,
There were drawbacks such as an excessive amount of air supplied to the furnace or insufficient pressure. As a result, combustion efficiency was low, and a large amount of harmful exhaust gas was emitted, which could lead to pollution problems.

That is, the sludge cake contains a lot of water, and it is very difficult to achieve self-combustion. From the standpoint of energy conservation, it is necessary to maintain the temperature inside the furnace at an optimum level in order to perform efficient operation that allows self-combustion, but conventional control devices do not have any means for this.

In addition, pollution problems in incinerators include NOx and H
These include the generation of harmful gases such as carbon dioxide, and the generation of toxic heavy metals that remain in soot and debris. Normally, in the conventional incinerator 1, harmful gases and soot and dust are removed by the exhaust gas treatment device 5, but from the standpoint of pollution removal, it is important to suppress the amount of exhaust gas as much as possible. However, conventional combustion control device pressures do not take this point into consideration.

Furthermore, there are 6 leftovers that are a particular problem when incinerating sewage sludge.
It is valent chromium. This is because chromium is oxidized to become a hexavalent compound, and the reaction is accelerated by calcium. In particular, with regard to sludge that has been treated with slaked lime, there is a high possibility that the residual material contains hexavalent chromium. In order to suppress the generation of hexavalent chromium, it is necessary to keep the atmosphere inside the incinerator in a cyclic state. However, conventional devices do not take this point into consideration much as described above. As mentioned above, from the perspective of pollution prevention, incineration in a low-oxygen atmosphere, that is, low-air combustion, is the best method.The effects of this low-air ratio combustion are a reduction in the amount of exhaust gas, a reduction in the amount of NOx generated, There are advantages such as a reduction in the amount of hexavalent tetrahydram generated and a reduction in the size of exhaust gas treatment equipment. In order to carry out low air ratio twisting/firing, control of the amount of combustion air is extremely important, but as mentioned above, the reliability of controlling the amount of air is poor with conventional equipment. There were drawbacks.

[Purpose of the invention]

The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional technology, and maintains optimal combustion conditions by controlling the input amount of materials to be incinerated such as sludge cake and the amount of combustion air. The purpose of the present invention is to provide a combustion control device for a multistage incinerator that has excellent energy saving effects and anti-pollution measures.

[Summary of the invention]

In order to achieve this objective, the present invention includes a supply amount control device for incinerated materials that increases or decreases the amount of incinerated materials supplied depending on the temperature situation in the furnace to suppress combustion fluctuations, and The oxygen concentration and A combustion air flow rate control device, a hot air stove fuel combustion control device that controls the fuel flow rate and combustion air flow rate of the hot air stove burner according to the temperature of the combustion stage of the furnace, and maintains the temperature inside the furnace at an optimum level; Recirculation gas flow rate control that controls the recirculation flow rate of exhaust gas by determining a target value for the recirculation gas flow rate based on the input amount of the incineration material and the combustion air flow rate based on the control output value of a temperature control device that is controlled to a predetermined value. and a furnace pressure control device that maintains the furnace pressure at a predetermined value by taking into account the fluctuation of the air amount due to the combustion air amount control.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a structural diagram of a general multi-stage incinerator to be controlled by the present invention, and the structure and incineration principle of the multi-stage incinerator 10 will be explained based on this diagram.

The structure of the furnace 10 has a multi-stage hearth 11 as shown in FIG. There is. A center shaft 14 rotatably supported by a center roller 13 passes through the center of the furnace body, and is rotated by a shaft drive motor 15 at a speed of usually about 0.5 to 1.5 rpm. A plurality of rapple arms (stirring arms) 16 are attached to this shaft 14, and rapple teeth (stirring teeth) 17 are attached to these ripple arms 16 for moving and stirring the materials to be incinerated such as sludge cake. ing. In order to protect the center shaft 14 from high temperature gas,
A cooling fan 18 constantly sends cooling air into the shaft 14 from below. A part of this cooling air is returned to the lower end of the furnace 10 via the air circulation pipe 19 and is used as combustion air, while the remaining air sent out from above the center shaft 14 is sent through the exhaust pipe. and is discharged to the outside air through the chimney. The hot air generating furnace 21 has a burner 2 inside.
2 is installed, and hot air is supplied into the furnace directly and through the branch chamber as an auxiliary heat source for starting up the furnace and for spontaneous combustion of the sludge cake. In addition to heavy oil, digester gas is also used as fuel for burner n.

The sludge cake behavior process is as follows: First, the sludge cake is introduced into the first hearth from the sludge inlet U at the top of the furnace, and as the center shaft 14 rotates, the sludge cake is stirred by the rapple teeth 17, ), and the sludge cake falls to the lower stage from the center droplet (or the outer droplet). Contrary to the previous step, the fallen sludge cake is pushed and spread toward the outer periphery (or the center) while being stirred, and falls to the lower stage from the outer periphery drop port (or the center drop port). Thereafter, while stirring and moving on each hearth, the ash sequentially falls to the lower stage, and finally is discharged as incinerated ash out of the furnace through an ash outlet chute 5 provided on the bottom hearth.

Combustion air is blown into the lower part of the furnace 10, and this air is normally heated as the center shaft 14 is cooled, and is supplied from the lower end of the furnace 1o via an air circulation pipe 19 for combustion. The air flows countercurrently to the upper stage while contacting the sludge cake, and is discharged outside the furnace from the exhaust gas outlet as combustion exhaust gas. Furthermore, this combustion exhaust gas is led to an exhaust gas treatment system.

The inside of the furnace is divided into three zones: the upper hearth is called the drying zone, the middle section is called the combustion zone, and the lower section is called the cooling zone. Here, in the drying zone, the combustion gas and the sludge cake come into contact, and water in the cake evaporates. The temperature inside the oven in the drying zone is usually about 150 to 500°C. In the combustion zone, the temperature inside the furnace is highest where the sludge cake is burned. The temperature of the combustion zone varies depending on the properties of the sludge cake, but
Generally, the temperature is about 650 to 850°C. Further, in the cooling zone, heat exchange occurs between the incinerated ash and the combustion air.

The general ambient temperature is about 200 to 300°C.

FIG. 3 is an overall configuration diagram of the multistage incinerator combustion control device. In the figure, the arrow ■ indicates an air line, the arrow @ indicates an exhaust gas line, and the arrow θ indicates a fuel line.

Here, each mechanical configuration will be explained. The feeding mechanism for materials to be incinerated, such as sludge cake, includes a quantitative feeder (dehydrated cake quantitative feeding machine) 30, a conveyor weighing scale 31, and an input conveyor 32, and a predetermined amount of sludge cake is supplied from the quantitative feeder (equipment). Then, the amount of this sludge cake is weighed by the conveyor weighing scale 31, and then transferred to the furnace 10 by the feeding conveyor 32.
The dehydrated cake is added according to the date of introduction. The combustion air supply mechanism causes cooling air sent out from the cooling fan 18 to pass through the center shaft 14 → air circulation pipe 19 → exhaust gas outlet 9.

The oxygen concentration in the furnace is detected by an oxygen concentration meter 40 installed at the furnace outlet, and the amount of combustion air is detected and adjusted by the air circulation pipe 1.
This is carried out using a flow meter 41 and a flow control valve 42 provided at 9.

The temperature of the combustion stage and drying stage in the furnace is determined by a temperature detector 33□ provided in the drying stage, and a temperature detector 33n provided in the combustion stage.
33n and 33n+1 are respectively detected. The hot air generating furnace fuel/air supply mechanism supplies a predetermined amount of fuel such as heavy oil and air to the burner of the hot air generating furnace 21, and the amount of fuel and air is measured by a flow meter W.

51 and adjusted by flow rate control valves 52 and 53.

The exhaust gas treatment mechanism consists of an exhaust gas exhaust system and an exhaust gas recirculation system. In the exhaust gas exhaust system, the exhaust gas taken out through the exhaust gas pipe 61 by the induction blower ω is cleaned in a gas cleaning tower 62, and then dust is removed by an electrostatic precipitator (E-P). It is sent to a reheating furnace 65 via a blower (IDF) 60, where it is subjected to white smoke prevention and deodorization treatment, and then discharged into the atmosphere from a chimney 66. On the other hand, the exhaust gas recirculation system uses a fan 67 to send the exhaust gas taken out through the exhaust gas pipe 61 to the lower stage of the furnace 10 via the exhaust gas circulation pipe section, thereby increasing thermal efficiency. The amount of circulating gas is detected by a flow meter 69 provided in the exhaust gas circulation pipe 68, and the flow rate is adjusted by a flow rate control valve 70. Furthermore, the pressure inside the furnace is detected between pressure gauges installed in the furnace 10, and based on this detected value, the opening of damper -B in the exhaust gas system is adjusted, and the inside of the furnace is maintained at a predetermined negative pressure. Ru.

A control circuit that controls the mechanical components as described above will be explained. This control circuit, that is, the control device includes a supply amount control device A for incinerated materials such as sludge cake, an oxygen concentration and combustion air flow rate control device B, and a hot air generating furnace fuel combustion control device C.
5 Consisting of a recirculation gas flow rate control device D, and an in-furnace pressure control device E.

In controlling the multistage incinerator 10, the amount of sludge cake to be treated and the calorific value of the sludge cake are set in advance by the operator before automatic control operation is performed.

Then, the sludge cake supply amount control device A issues commands to increase or decrease the supply amount depending on the temperature condition inside the furnace, thereby suppressing fluctuations in combustion due to differences in the properties of the sludge cake as much as possible. The calorific value of the sludge cake is determined by correcting the value obtained from the deviation output signal from the oxygen concentration control device. The combustion air flow rate control device calculates the air-fuel ratio from the calorific value of the sludge cake, and adjusts the amount of air so as not to produce excess air. The hot air generating furnace fuel combustion control device C performs combustion control of the hot air generating furnace 21 so that the combustion stage temperature of the furnace 10 (generally the middle stage temperature as a representative temperature of the combustion stage) falls within a certain range. That is,
In the case of sludge incineration, the possibility of self-combustion combustion is low, so the amount of heat is replenished by the hot air generating furnace 21 to maintain the temperature inside the furnace at an optimum level. The recirculation gas flow control system recirculates the exhaust gas to facilitate drying of the sludge cake in the drying stage of the furnace 10 and to increase combustion efficiency within the furnace. Further, the furnace pressure control device E maintains the inside of the furnace at a constant negative pressure in consideration of furnace safety, combustion efficiency, and the like. Below, each control device A-E
will be explained with reference to FIG. 3 and FIGS. 4 to 9 showing details thereof.

(1) Sludge cake supply amount control device A FIG. 4 is a detailed diagram of the sludge cake supply amount control device A.

In this supply amount control, the standard input amount W is initially set by the setting device 100. is manually set, and when the furnace 10 enters steady operation, the standard input amount W0 is corrected and calculated at regular intervals based on the temperature information in the furnace, the target sludge cake amount is determined, and the rotation speed of the metering feeder blade is controlled. Let's do it.

That is, the temperature of the dried film in the furnace 10 is determined by the temperature detector 33□.
Furnace 1 by temperature detectors 33n-8, 33n, 33n+1
The combustion stage temperature of 0 is detected respectively. Each of these temperature detectors 331t''3n-0, 33n, and n+□ is installed in at least one pair or more to increase the detection accuracy, and the temperature averaging circuit 101.102.103.104
After calculating the respective average values, the furnace temperature distribution determination circuit 10
given to 5. Generally, the optimum combustion state is the temperature distribution of the combustion stage where the middle stage temperature (detected value of temperature detector 33n) Tn has the maximum peak, while the upper stage temperature of the combustion stage (temperature detector 33n-□) When the Tn-
When Tn+1 (detected value of temperature detector 33n+1) reaches its maximum peak, it indicates that the combustion condition is not normal and burnout is poor. It is necessary to control the directional pressure to reduce. Therefore, the first determination circuit 105□ in the furnace temperature distribution determination circuit 105 determines that the input amount is insufficient when ■Tn, )Tn, Tn+□, outputs the increase correction signal α, and also outputs ■Tn+i.
> Tn I When Tn-1, it is determined that the input amount is excessive, and a reduction correction signal α2 is output. Furthermore, when the drying membrane temperature (detected value of temperature sensor O) T1 is higher than the specified temperature, the amount of sludge is small (meaning that the amount of heat exchanged by contact with exhaust gas is small, so the amount of sludge input is increased). It is necessary to control the directional pressure.For this reason, the furnace temperature distribution determination circuit 105
The second determination circuit 1052 in the middle determines that the input amount is insufficient when T□>T, and outputs an increase correction signal α3. However, T is the specified temperature.

Here, due to the characteristics of a multi-stage furnace, there is a very large time delay from when the sludge cake is introduced into the furnace until it is combusted. Therefore, taking this time delay into consideration, the on-delay timers 106 and 107 adjust the output signal α of the determination circuit 105.
1. α2. α3 is delayed for a certain period of time to provide sludge cake amount correction calculation circuit 108K. Then, this modified calculation circuit 1
08, the reference input amount Wo and the correction signal α1. α2.
If the condition continues for a certain period of time from α, the input amount is corrected, and this calculated value Wn'ttVXJ limiter
After the amplitude is controlled in step 09, it is applied to a cake quantity indicating controller (WIC) 111 via a changeover switch 110. Here, the changeover switch 110 enters the K"1" mode at the start of operation, and the reference input amount W is set. is given to the cake amount indicating controller 111 K, but enters the II 21+ mode during steady operation, and the calculation amount W of the arithmetic circuit 108 is given to the cake amount indicating controller 111.
give to

The cake amount indicating controller 111 determines the optimum quantitative feeder rotation speed from the corrected calculation value Wn and the input cake amount measurement value of the conveyor weighing scale 31, and controls the rotation speed of the quantitative feeder (material) to adjust the cake input amount. Make adjustments. As described above, the target input amount W0 is increased or decreased depending on the temperature conditions inside the furnace. Note that, depending on the characteristics of the furnace 10, the above conditions may not be applicable in some cases, so the determination conditions are actually confirmed through on-site verification, and the determination method is changed as appropriate depending on the situation.

(2) Oxygen concentration and combustion air flow rate control device B FIG. 5 is a detailed diagram of this control device B. Low air volume control is an important point from the perspective of pollution prevention. Therefore, this control device B adopts a method of determining the theoretical amount of air required to burn the sludge cake from the calorific value of the sludge cake.

That is, initially, the sludge cake and the standard calorific value Huo are manually set using the setting device 120. On the other hand, the oxygen concentration in the furnace is detected by the oxygen concentration meter 40, and this detected value is given to the Z limiter 122 via the oxygen concentration meter abnormality detector 121. After the amplitude is limited by this L limiter 122, the oxygen concentration is The signal is given to the concentration indicator controller (0, IC) 123. The controller 123 determines the amount of deviation MY from the target value, and provides it to the calorific value correction calculation circuit 126 via the Ipb limiter 124 and changeover switch 125. Here, if the oxygen concentration meter 40 is not malfunctioning, the changeover switch 125 is set to
I111 mode is entered, and the output value MV of the oxygen concentration indicating controller 123 is given to the correction calculation circuit 126. However, if the concentration meter 40 malfunctions, the abnormality detector 121 detects this and switches on the changeover switch 125. Since the mode is switched to 1121 mode, the fixed value MV0 is given to the modification calculation circuit 126.

This provides countermeasures in the event of an oxygen concentration change course failure. In the calorific value correction calculation circuit 126, the standard calorific value is 9. From the output value MV of the oxygen concentration and the output value MV of the oxygen concentration, a corrective calculation of the calorific value is performed based on the following equation to obtain the optimal calorific value Hu.

However, kl is a constant.This calorific value 9 is given to the air-fuel ratio calculation circuit 128 via H7,y 27. This calculation circuit 128 calculates the air-fuel ratio corresponding to the nuclear heating value Hu, and multiplier 129
give to On the other hand, the sludge cake input amount W (*1 in Fig. 3) measured by the conveyor weighing scale 31 is determined by the delay circuit 13.
0 and after a certain period of time has elapsed, it is applied to the multiplier 129. Then, the multiplier 129 calculates the required combustion air flow rate Ar by calculating the following equation, and then calculates the required combustion air flow rate Ar.
give.

A, =, XLXW However, k2: Constant On the other hand, the detected value (differential pressure) detected by the differential pressure type flowmeter 41 is given to the square root calculator 132, and the combustion air flow rate is calculated by this calculator 132 and the above It is given to the controller 131. Therefore, the controller 131 calculates the deviation value from the air flow rate A and supplies it to the flow rate control valve 42 via the L limiter 133 to control the amount of combustion air supplied to the furnace trap.

The control of the amount of combustion air as described above proceeds as shown in FIG. That is, if the set calorific value H6o is too high, the set air-fuel ratio is high, and therefore the combustion air flow rate is too much than the actual required air amount. This means that the measured oxygen concentration is high. Therefore, in the calorific value correction calculation circuit 126,
A correction is made to reduce the calorific value H by lowering the oxygen concentration control MV value, and the amount of combustion air is controlled based on this correction value.

(3) Hot blast furnace fuel combustion control device C Figure 7 is a detailed diagram of this control device C. Hot blast furnace fuel combustion control is performed by controlling the fuel flow rate and combustion air flow rate of the hot blast burner n depending on the middle stage temperature of the combustion stages. It controls the

The middle temperature Tn of the furnace 10 is determined by installing at least two temperature detectors 33n (33n1, 33n2) in pairs in the furnace, and transmitting the detection signals of these two temperature detectors 33n and 33n2 to the temperature detection abnormality detector 140. Temperature averaging circuit through 141 K
This circuit 141 calculates the temperature average value. here,
When there is a failure in the temperature detectors ON1 and 33N2, the temperature detection abnormality detector 140 is activated and changes over the changeover switch 142, causing the temperature averaging circuit 141 to output a normal temperature detector signal. is increasing its reliability. This output signal is transmitted to the hot air stove combustion control setting calculation circuit 14.
given to 3.

A computing unit 143□ in this computing circuit 143 calculates a set value Sv of the hot blast stove burner n from the hot blast stove burner combustion characteristic curve determined by the combustion stage temperature as shown in FIG. Note 1. In FIG. 8, the solid line shows the combustion characteristic curve from burner ignition to extinguishing, and the broken line shows the combustion characteristic curve from burner extinguishing to ignition. The temperature range of TH<T indicates the self-combustion region of the sludge cake, so in this temperature range, combustion of the hot-air burner n is stopped, and in the temperature range of TA<T<TH, the hot-air burner is turned off to accommodate the internal temperature of the furnace. It is necessary to control the combustion of the burner η, and in order to speed up the heating in the furnace in the temperature range T<TA, the burner n must be burnt in a state close to full operation but still effective. In addition, in order to prevent burner combustion from repeatedly turning on and off at a temperature near the natural point TH, the dead zone setter 143□ in the arithmetic circuit 143 sets a dead zone Tn-d<T<Tn, so that the furnace temperature is Tn-d. I set it to 5 so that the burner combustion starts only when the temperature drops to 5. Target value S of burner combustion determined as above
is applied to the fuel flow control system and combustion air flow control system of burner n.

In the burner fuel flow control system, the fuel flow indicator controller 144
PID control of the fuel flow rate is performed using the target value Sv,
The opening degree of the flow control valve 52 is adjusted. On the other hand, the burner fuel air flow rate control system performs ratio control based on the fuel flow rate to control the combustion air flow rate. That is, based on the detected value between the fuel flowmeters, a ratio is set in the fuel flow meter (SK) 145 to obtain a target air amount, and this target air amount is provided to the air flow rate indicating controller 146. The controller 146 calculates the target air amount, the differential pressure flow meter 51 and the square root calculator 147.
A control signal that makes the deviation value between the two zero is output from the measured flow rate obtained from
The amount of air is controlled by adjusting the opening degree in step 3.

Here, in order to improve responsiveness, the target value Sv of burner combustion is added to the control output of the combustion air flow rate by an adder 148, and the flow control valve 53 is
Try to give it to Although heavy oil or the like is generally used as a fuel, if the digestion gas generated at a sewage treatment plant is shared, it is necessary to change the ratio of air flow rate control by fuel switching. Therefore, with the changeover switch 150 operated manually or by an external contact, the digestion gas ratio KA is
, the heavy oil ratio KB can be switched.

By performing combustion control as described above, fuel savings and
Energy saving efficiency can be expected.

(4) Recirculation gas flow rate control device FIG. 9 is a detailed diagram of this control device. The sludge cake comes into contact with the exhaust gas in the drying stage, evaporates water and dries.
The amount of exhaust gas supplied to this drying stage is given in accordance with the amount of sludge cake. In this control, the amount of correction of the dry film temperature T□ is determined by the temperature indicating controller 160, and this temperature control output value MV is determined. Based on the values of the sludge cake input amount W and the combustion air flow rate F (*l and *2 in Fig. 3), the recirculation gas flow rate setting calculation circuit 161 uses the recirculation gas flow rate target value s■
is calculated and provided to the gas flow rate indicating controller 163 via the μt limiter 162. Then, the controller 163 calculates the amount of deviation from the target value S■ based on the measured gas flow rate obtained from the flow meter 69 and the square root calculator 164K, and provides a correction signal to the flow rate control valve 7o. This allows the gas flow rate to be controlled to the optimum level.

(5) Furnace pressure control device E As shown in Fig. 3, in this furnace pressure control, the pressure indicating regulator 170 calculates the deviation amount between the furnace pressure determined by the pressure gauge (equipment) and the target value. and outputs a correction signal. Then, the opening degree of the damper 64 of the induced blower ω is adjusted by this correction signal, and the inside of the furnace is maintained at a constant negative pressure. here,
In order to improve the responsiveness of the control, K is added by the adder 171,
The amount of combustion air determined by the flow meter 41 and the square root calculator 132 (*2 in Fig. 3) is added to the output value of the pressure indicating controller 170, and the furnace internal pressure is controlled taking into account factors due to fluctuations in the amount of combustion air. conduct.

As explained above, in this embodiment, the amount of sludge cake input and the hot air generating furnace are controlled based on the temperature inside the furnace to keep the temperature inside the furnace constant, and the amount of sludge input and the calorific value of the sludge are Based on this, the air-fuel ratio is maintained at an optimum level, excessive air supply is avoided, and the furnace 10 is operated efficiently. On the other hand, in order to evaporate the moisture in the sludge cake, the sludge cake is dried using exhaust gas in the drying stage of the furnace 10. Then, the recirculation gas flow rate is calculated and the optimum amount of exhaust gas is supplied to the drying stage of the furnace 10. Therefore, optimal air flow control results in effective control for energy saving and pollution control.

〔Effect of the invention〕

As explained above, in the present invention, the amount of material to be incinerated and the hot air generation furnace are controlled based on the temperature inside the furnace to keep the temperature inside the furnace constant, and the amount of material to be incinerated and the calorific value of sludge are Keep the air-fuel ratio optimal and avoid excessive air supply to ensure efficient furnace operation.

Furthermore, the optimal recirculation gas flow rate is supplied based on the amount of sludge cake input, the amount of combustion air, and the temperature inside the furnace to promote drying of the material to be incinerated. This will help save energy and prevent pollution.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a conventional multi-stage incinerator combustion control device, Figure 2
The figure is a structural diagram of a general multistage incinerator to be controlled by the present invention, Figure 3 is an overall configuration diagram of a combustion control device according to an embodiment of the present invention, and Figure 4 is a sludge cake etc. in Figure 3. 5 is a detailed explanatory diagram of the device for controlling the supply amount of the incinerated material, FIG. 5 is a detailed explanatory diagram of the oxygen concentration and combustion air flow rate control device in FIG. 3, FIG. The figure is a detailed explanatory diagram of the hot stove fuel combustion control device in Figure 3, Figure 8 is an explanatory diagram of the operation of the combustion control setting calculation circuit in Figure 7, and Figure 9 is the recirculation gas flow rate in Figure 3. It is a detailed explanatory diagram of a control device. A: Supply amount control device for materials to be incinerated such as sludge cake, B
...Oxygen concentration and combustion air flow rate control device, C...
Hot air generating furnace fuel combustion control device, D... Recirculation gas flow rate control device, E... Furnace pressure control device, 10... Multi-stage incinerator, 21... Hot air generating furnace, 31... Weight Meter, A□, 33n-1, 33n, 33n+1...Temperature detector, 40...Oxygen concentration meter, 41, 50, 51, 6
9...Flowmeter, 42, 52. 70...Flow control valve, 64...Damper, (equipment)...Pressure gauge, 100...Reference input amount setting device, 10
5...Furnace temperature distribution determination circuit, 108...Sludge cake amount correction calculation circuit, 111...Weight indicating controller, 120...
...Reference calorific value setting device, 123... Oxygen concentration indicating controller, 126... Calorific value correction calculation circuit, 128... Air-fuel ratio calculation circuit, 129... Multiplier, 131... Flow rate indication Controller, 143...Hot blast furnace combustion control setting calculation circuit, 144...Flow rate indicating controller, 145...Scaling, 146...Flow rate indicating controller, 148...Adder, 160... Temperature indication adjustment needle, 161... Recirculation gas flow rate setting calculation circuit, 163... Flow rate indication controller,
170...Pressure indicating controller, 171...Adder. Applicant's agent Kiyoshi Inomata Figure 6 En V Tech procedural amendment February 10, 1949 Leap Year Kazuo Wakasugi, Commissioner of the Patent Office1, Indication of the case 1982 Patent Application No. 2280282, Name of the invention Multi-stage incineration Furnace combustion control device 3, person making amendment Patent applicant (307) Tokyo Shibaura Electric Co., Ltd. 7, subject of amendment 'Drawing 8, contents of amendment Engraving of drawing (no change in content)

Claims (1)

[Scope of Claims] 1. The amount of heat is replenished by a hot air generating furnace, the material to be incinerated is burned in the combustion stage hearth, and the combustion exhaust gas generated from this trap is used to newly inject the material to be incinerated in the dry membrane hearth. In a multi-stage incinerator that evaporates moisture from materials, the standard input amount of materials to be incinerated is corrected and calculated based on the temperatures of the drying stage and combustion stage in the furnace to determine the target input amount, and the amount of materials to be incinerated is determined based on this target input amount. The reference calorific value of the incinerated material is corrected and calculated based on the control signal of the supply amount control device of the incinerated material and the oxygen concentration control device that controls the oxygen concentration in the furnace to a predetermined value. Calculating the air-fuel ratio and calculating the amount of combustion air from this air-fuel ratio and the input amount of the material to be incinerated,
The oxygen concentration and combustion air flow rate control device that controls the amount of combustion air in the furnace uses this amount of air, and the temperature of the combustion stage of the furnace calculates a target value for the combustion heat amount of the hot air generating furnace burner. A hot blast furnace fuel combustion control device that controls the fuel flow rate, calculates the amount of combustion air in the burner based on the fuel flow rate in the burner, and controls the amount of combustion air in the burner based on the air amount; Recirculation that calculates a target value for the recirculation gas flow rate based on the control output value of the temperature control device to be controlled, the input amount of the material to be incinerated and the combustion air flow rate, and controls the recirculation flow rate of the exhaust gas using this target value. A combustion control device for a multi-stage incinerator, comprising: a gas flow rate control device; and an in-furnace pressure control device that suppresses fluctuations in the amount of combustion air due to the combustion air amount control and controls the in-furnace pressure to a predetermined value.