JPH09273733A - Control method of combustion in incinerating furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To incinerate wastes efficiently and supply steam stably. SOLUTION: A primary air damper 14 is controlled based on the measuring value of generating amount of steam, measured by a flow meter 12, and, at the same time, respective opening degrees of an air damper 13a below the fore part of drying grating, an air damper 13b below the fore part of combustion grating, an air damper 13c below the rear part of the combustion grating and an air damper 13d below the rear part of a rear combustion grating as well as the speed of a combustion grating 3b are controlled. The control of a secondary air volume damper 10b is controlled in parallel based on the measurement of a concentration meter 17 for exhaust gas O2 while synchronizing with the control of the air dampers. According to this method, wasteful blowing of air is eliminated and the generating amount of steam can be stabilized while the generation of unburned gas is restrained and utilizing efficiency of combustion energy of wastes can be increased.

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 combustion in a grate-type refuse incinerator, and more particularly to a method for preventing fluctuations in combustion and stabilizing the amount of steam generated by controlling the amount of air and the speed of a combustion grate.

[0002]

2. Description of the Related Art Municipal solid waste incinerators play an important role in treating various wastes discharged in social life. In recent years, interest in recovering the enormous amount of heat energy generated by incineration of waste, which is waste, has increased, and the number of boilers equipped with a power generation facility has increased.

[0003] In a refuse incinerator, refuse is intermittently put into a hopper by a crane at intervals of several tens of minutes, a drying grate is provided under the hopper, and the refuse is continuously fed into the furnace by the drying grate. . There is a damper under the drying grate, and the primary air blown from here dries mainly the dust. The dry grate is followed by the combustion grate to sequentially send refuse, the amount of which can be varied by the speed of the grate.

Below the combustion grate are a front damper and a rear damper, from which the primary air blown is used for combustion. In addition, the combustion grate is followed by the post-combustion grate,
There are also dampers below it, and the primary air blown from them is used to burn out the waste. These dampers are dampers for distributing primary air, and the total amount of primary air is adjusted by the primary air damper.

On the other hand, secondary air is blown from above the combustion zone to completely oxidize the unburned gas and to control the temperature in the furnace. The secondary air mixes with the combustion gas in the mixing chamber near the furnace outlet, prevents overheating of the furnace wall, and oxidizes the remaining unburned components. The mixed gas is
The heat exchanger provided at the outlet of the furnace gives heat to the boiler and then exhausts it.

[0006] In such a refuse incinerator, automatic combustion control is performed in order to achieve complete combustion of the refuse and to improve the efficiency of recovery of the combustion energy of the refuse and to stabilize the furnace outlet temperature and obtain a constant steam generation amount. ing. As the control means, there is a means for controlling the primary air amount, the secondary air amount, or the grate speed control for controlling the feed amount of dust. Then, usually, every time dust is put into the hopper at intervals of several tens of minutes, based on the results before that, the primary air amount, the secondary air amount, the reference value of the grate velocity and the target amount of the generated steam amount, etc. Is determined.

However, the dust thrown into the hopper of the incinerator is not uniform in its properties and components, and is easily combustible and difficult to combust. Therefore, even if the primary air amount, the secondary air amount, the grate velocity, etc. are controlled so as to maintain the reference values, the calorific value due to the combustion of dust will not be constant, leading to fluctuations in the furnace outlet temperature and steam generation amount. .

Conventionally, in order to suppress this fluctuation, a method has been proposed in which the steam generation amount is constantly measured and the air amount is adjusted. For example, in Japanese Unexamined Patent Publication No. 4-371712, a boiler water pipe that constitutes a combustion chamber in response to a sudden change in the steam generation amount while controlling the amount of waste feed to suppress long-term fluctuations in the steam generation amount A control method is described that measures the amount of evaporation in the panel and adjusts the ratio of the total primary air amount under the grate and the secondary air amount blown directly into the furnace chamber based on the measured value under a constant total air amount. There is. In this control, when the steam generation amount exceeds the target amount, the primary air amount is reduced, and when it is below the target amount, the primary air amount is increased.

[0009]

However, in the above control method, the total amount of primary air is controlled, but the distribution of the amount of air blown up from under each grate is not taken into consideration. Therefore, the expected effect may not be obtained. For example, when the steam generation amount falls below the target amount, the steam generation amount is quickly recovered to increase the primary air amount and activate combustion. At this time, if the distribution of the amount of air under each grate is not taken into consideration, useless primary air is blown into the furnace, which cools the inside of the furnace and rather delays the recovery of combustion. In this case, the amount of steam generated is not recovered, but only the amount of unburned gas generated is increased.

On the contrary, when the amount of steam generated exceeds the target amount, the amount of primary air is reduced in an attempt to quickly reduce the amount of steam generated to the target amount, thereby suppressing combustion. However, if the distribution of the amount of air under each grate is not taken into consideration, the amount of combustion air in the active combustion grate part may not be sufficiently reduced, and combustion may not be suppressed.

Furthermore, when the amount of steam generated decreases,
The combustion of dust on the grate becomes unstable, the temperature of the gas mixing chamber decreases due to the dead air in the furnace, the secondary combustion reaction in the gas mixing chamber decreases, and the CO in the exhaust gas decreases. Unburned components such as may increase. On the contrary, when the amount of generated steam is increasing, the O ₂ concentration in the exhaust gas is low, so that unburned components may be generated due to lack of O ₂ .

The present invention has been made to solve the above-mentioned problems, and controls distribution of the primary air amount by controlling a plurality of air dampers, or simultaneously controls the secondary air amount, or By controlling the combustion grate velocity together with the control of the air volume, the efficiency of recovery of the combustion energy of the waste is improved, the amount of steam generated is stabilized, and the unburned components are prevented from being generated. It is intended to provide a combustion control method.

[0013]

Means for achieving this object are the following first to seventh means.

The first means is to measure the amount of steam generated in combustion control of a refuse incinerator that burns the waste while moving it on the grate and uses the combustion heat to generate steam.
This is a combustion control method for a refuse incinerator in which the primary air damper opening is controlled based on the measured value and the damper opening under each grate is controlled to adjust the air amount.

While measuring the amount of steam generated, the damper opening is controlled so that the amount of steam generated does not deviate from a certain range. However, the action is slightly different depending on the position where the primary air is blown. The air blown under the dry grate takes away moisture, the air blown under the combustion grate supplies O _2, and in the post-combustion grate there is much ash,
The air blown into here consumes only part of the O ₂ .

Therefore, the expected effect can be obtained by controlling the primary air damper opening and controlling each damper opening.

A second means is to select the operation (A) below when the steam generation amount is larger than the target amount in the first means, and to perform the next operation when the steam generation amount is smaller than the target amount. This is a combustion control method for a refuse incinerator in which the operation of (B) is selected to control the damper opening to adjust the amount of primary air.
In (A), the opening of the primary air damper is reduced, the openings of the front lower air damper of the combustion grate and the lower rear air damper of the combustion grate are decreased, and the air damper under the dry grate and the air under the rear combustion grate are reduced. It is an operation to increase the opening of the damper,
(B) shows that the opening of the primary air damper is increased, the openings of the front lower air damper of the combustion grate and the rear lower air damper of the combustion grate are increased, and the air damper under the dry grate and the air under the post combustion grate are increased. This is an operation to reduce the opening of the damper.

If the opening of the primary air damper is reduced to reduce the amount of primary air when the amount of steam generated is large, the combustion speed is reduced and the amount of steam generated is suppressed. However, when viewed individually, it is the amount of primary air supplied to the combustion grate, not the primary air supplied to the dry grate or post-combustion grate, that must be reduced. Since the latter primary air is only used for combustion, it acts rather on cooling.

For this reason, the opening degrees of the front lower air damper of the combustion grate and the lower rear air damper of the combustion grate are reduced, and the opening degrees of the air damper under the dry grate and the air damper under the rear combustion grate are increased. The amount of steam generated can be suppressed faster.

When the opening amount of the primary air damper is increased to increase the primary air amount when the steam generation amount is small, combustion is promoted and the steam generation amount increases. However, also in this case, it is the combustion grate that needs to increase the primary air amount. It is better to reduce the primary air that also has a cooling effect that is supplied to the dry grate and the post-combustion grate.

Therefore, by increasing the openings of the combustion grate front lower air damper and the combustion grate rear lower air damper, and by decreasing the openings of the dry grate lower air damper and the post combustion grate lower air damper. The amount of steam generated can be increased quickly.

Further, since the opening degree of each air damper is individually controlled as described above, unnecessary air is not blown in, so that the combustion zone is not excessively cooled and the generation of unburned components is prevented. It

The third means adjusts the amount of primary air by the second means, measures the O ₂ concentration in the exhaust gas, and when the O ₂ concentration in the exhaust gas is low, the damper opening degree of the secondary air. Is large and the O ₂ concentration in the exhaust gas is high, it is a combustion control method for a refuse incinerator in which the damper opening degree is controlled to reduce the secondary air damper opening degree to adjust the secondary air amount.

The O ₂ concentration in the exhaust gas reflects the combustion state.
When the combustion of the waste is stable, the O ₂ concentration in the exhaust gas is within the proper range. Even if the second measure is taken, the O ₂ concentration in the exhaust gas may sometimes fluctuate due to the instability of the properties of dust.

In order to detect this situation, the O ₂ in the exhaust gas is measured and the secondary air is adjusted in addition to the adjustment of the primary air to deal with the instability of the property of the waste.

When the O ₂ concentration in the exhaust gas is low, the dust is difficult to burn and the unburned components increase due to incomplete combustion. At this time, the opening degree of the secondary air damper is increased to increase the amount of secondary air and promote secondary combustion to burn out unburned components.

On the contrary, when the O ₂ concentration in the exhaust gas is high, more air is supplied than is necessary for burning the dust. At this time, the opening of the secondary air damper is reduced to reduce the amount of secondary air.

By these operations, it is possible to further prevent waste air from being blown in and to fully utilize the combustion energy of dust to suppress the discharge of unburned components.

The fourth means is the first means, the second means,
A third method is a combustion control method for a refuse incinerator that uses fuzzy control to control an air damper.

As described above, the property of dust is indefinite, the amount of heat of combustion is not constant, and the easiness of burning changes every moment. Therefore, by measuring the amount of steam generated, controlling multiple air dampers,
Alternatively, a plurality of air dampers are controlled by measuring the steam generation amount and the O ₂ concentration in the exhaust gas. As described above, the fuzzy control is the most suitable as a control method for obtaining a plurality of outputs from a plurality of inputs.

The fifth means adjusts the primary air amount by the second means, and when the steam generation amount is smaller than the target amount, increases the combustion grate velocity so that the steam generation amount is smaller than the target amount. It is a combustion control method for a refuse incinerator that controls the combustion grate speed to reduce the combustion grate speed when there is too much.

When the amount of steam generated is smaller than the target amount, the second means increases the supply of air to the combustion grate, but at the same time, by increasing the speed of the combustion grate, the fuel is also increased to promote combustion. , Increase steam generation. On the contrary, when the combustion is active and the amount of steam generated is larger than the target amount, the supply of air to the combustion grate is reduced by the second means, but at the same time, the fuel is also reduced by reducing the velocity of the combustion grate. Reduce the amount of combustion. In this way, the deviation of the steam generation amount from the target amount can be eliminated in a shorter time by adjusting the primary air amount and operating the combustion grate velocity.

The sixth means adjusts the primary air amount and the secondary air amount by the third means, and increases the combustion grate velocity when the steam generation amount is smaller than the target amount,
This is a combustion control method for a refuse incinerator, which controls the combustion grate speed to decelerate the combustion grate speed when the steam generation amount is larger than the target amount.

When the amount of steam generated is smaller than the target amount, the supply of air to the combustion grate is increased by the third means and the amount of secondary air is adjusted by the O ₂ concentration in the exhaust gas. By increasing the speed, fuel is also increased to promote combustion and increase the amount of steam generated.

On the other hand, when combustion is vigorous and the amount of steam generated is larger than the target amount, the supply of air to the combustion grate is reduced by the third means and the amount of secondary air is adjusted by the O ₂ concentration in the exhaust gas. Adjustment is made, but at the same time, the fuel amount is reduced by reducing the combustion grate velocity to reduce the combustion amount.

Thus, by manipulating the combustion grate velocity as well as adjusting the primary and secondary air amounts,
Prevents the useless blowing of air and suppresses the discharge of unburned components,
Moreover, the deviation of the steam generation amount from the target amount can be eliminated in a shorter time.

The seventh means is a combustion control method for a refuse incinerator which uses fuzzy control for controlling the air damper opening and controlling the combustion grate velocity, which is performed by the fifth means or the sixth means.

In the fifth means, a plurality of air damper openings and a combustion grate velocity are controlled in order to stabilize the combustion state in the furnace and make the generated steam amount constant. Then, in addition to this, the sixth means measures the O ₂ concentration in the exhaust gas and adjusts the secondary air amount in order to positively suppress the unburned components in the exhaust gas. In this way, fuzzy control is suitable as a control method that requires a plurality of outputs or obtains a plurality of inputs.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the invention will be described with reference to the drawings. FIG. 1 is a diagram showing the concept of a refuse incinerator and a control system. In FIG. 1, reference numeral 1 designates a furnace, which has a dust inlet 2, a dry grate 3a, a combustion grate 3b, a post-combustion grate 3c, and an ash drop port 4. Dry air or combustion air supplied by the primary air blower 5 is blown up from under each grate, and the dust introduced from the dust inlet 2 is dried by the dry grate 3a and burned by the combustion grate 3b. However, the post-combustion grate 3c is completely combusted to form ash. This ash is discharged out of the furnace through the ash drop port 4.

On the other hand, above the combustion zone, secondary air is blown from the blowing port 9 to oxidize unburned components and prevent overheating of the furnace. This secondary air is supplied by the secondary air blower 10a, and its amount is adjusted by the secondary air damper 10b.

In order for the secondary air to mix well with the combustion gas,
An inclined partition wall 6 is provided above the blow-in port 9. The mixed combustion gas and secondary air bypass the partition wall 6 and flow into the mixing chamber 7 above the partition wall 6, where the oxidation reaction is completed and the mixture goes to the furnace outlet.

At the furnace outlet from which exhaust gas is discharged, a heat exchanger 8
a steam generating boiler 8b equipped with a is installed,
Exhaust gas is heated here to the boiler water and then guided to the chimney and discharged outside the furnace. Reference numeral 11 is a thermometer for measuring the furnace outlet temperature in the exhaust gas, and 12 is a flow meter for measuring the steam generation amount.

The total amount of the primary air is adjusted by the primary air damper 14, and the air grate under the dry grate 13a for adjusting the amount of air to the dry grate and the combustion grate for adjusting the amount of air to the first half of the combustion grate. It is distributed by a front lower air damper 13b, a combustion grate rear lower air damper 13c that adjusts the amount of air to the latter half of the combustion grate, and a rear combustion grate lower air damper 13d that adjusts the amount of air to the rear combustion grate. It Reference numeral 15 is a primary air / under-grate air damper control means, which receives a signal from the steam flow meter 12 as an input, and receives the primary air damper 14, the dry grate lower air damper 13a, the combustion grate front lower air damper 13b, and the combustion fire. Signals are output to the rear lower air damper 13c of the grate and the lower air damper 13d of the post combustion grate.

16 is an exhaust gas CO concentration meter, 17 is an exhaust gas O
_{2 is a} densitometer. Reference numeral 18 denotes a secondary air damper control means, which receives signals from the exhaust gas O ₂ concentration meter 17 and the flow meter 12 for measuring the amount of steam generated, and outputs the signals to the secondary air damper 10b.

Reference numeral 20 denotes a combustion grate speed control means, which receives a signal from the flow meter 12 and outputs a signal to the combustion grate driving device 19 to control the speed of the combustion grate 3b. Primary air / under-grate air damper control means 1
For example, a computer is used for the secondary air damper control means 18 and the combustion grate speed control means 20.

First, the control of the air damper opening for the primary air and its distribution will be described. The control value of the air damper opening under each grate is calculated using the following equations (1) to (4).

[0047]

[Equation 1]

[0048]

[Equation 2]

[0049]

(Equation 3)

[0050]

(Equation 4)

Here, D ₁ is a dry grate lower air damper control value, D ₂ is a combustion grate front lower air damper control value, D ₃
Is a control value for the rear lower air damper of the combustion grate, and D ₄ is a control value for the lower air damper of the rear combustion grate. Further, D ₁₀ is a dry grate lower air damper reference value, D ₂₀ is a combustion grate front lower air damper reference value, D ₃₀ is a combustion grate rear lower air damper reference value,
D ₄₀ is an air damper reference value under the post-combustion grate.

Further, k ₁ is a dry grate lower air damper control parameter, k ₂ is a combustion grate front lower air damper control parameter, k ₃ is a combustion grate rear lower air damper control parameter, and k ₄ is a post combustion grate. This is a lower air damper control parameter. Note that STM _NOW represents the amount of steam generated,
_SET represents the target steam generation rate.

The control value of the opening of the primary air damper is calculated by a PID calculator that performs proportional, integral, and derivative operations based on the deviation between the steam generation amount and the target steam generation amount. The primary air damper control value D ₅ is calculated by the following equation (5).

[0054]

(Equation 5)

Where D ₅₀ is the primary air damper reference value, k
_5P , _k5I , _k5D are primary air damper control parameters, and S is a Laplace operator.

Next, the case where the secondary air amount is adjusted together with the primary air amount will be described. In this case, the secondary air damper control value D ₆ is calculated by the following equation (6).

[0057]

(Equation 6)

Here, D ₆₀ is the secondary air damper reference value, k
_6P , _k6I , _k6D are secondary air damper control parameters, and S is a Laplace operator.

Note that STM _NOW represents the steam generation amount, STM _SET represents the target steam generation amount, OXG _NOW represents the O ₂ concentration in the exhaust gas, and OXG _SET represents the O ₂ concentration reference value in the exhaust gas. Further, the reference value of each damper is a parameter that depends on the quality of waste and the amount of incineration, and generally varies depending on the waste collection area and season.

Further, the case where the combustion grate velocity is controlled together with the adjustment of the primary air amount or the adjustment of the primary air amount and the secondary air amount will be described. In this case, the control value of the combustion grate velocity is calculated by the following equation (7).

[0061]

(Equation 7)

Where S ₁ is the combustion grate velocity control value, S
₁₀ is a combustion grate velocity reference value, k _s is a combustion grate velocity control parameter, STM _NOW is an evaporation amount, and STM _SET is a target evaporation amount. The reference value of combustion grate velocity is also a parameter that depends on the quality of waste and the amount of incineration.

Next, regarding the case of performing fuzzy control,
The primary air and its distribution will be described. Table 1 shows the rules of fuzzy control.

[0064]

[Table 1]

In order to organize rules (1) to (3) in Table 1 for the antecedent part and the consequent part, and to make an inference in the consequent part,
The consequent part control parameter Y is defined and shown in Table 2. Y _n1 is positive in increments, Y _n2 is 0, and Y _n3 is negative in decrements.

[0066]

[Table 2]

The operations of these rules (1) to (3) are performed based on the membership function shown in FIG. The inference result of the consequent part of each rule obtained by the primary air / under-grate air damper control means is integrated, and the inference result of the entire rule is output. To integrate the consequent reasoning results of each rule,
A general method of fuzzy operation, for example, min-max
The center of gravity method and the singleton method are used.

The operation by the singleton method, which is fast and practical, will be exemplified below. In FIG. 2, it is assumed that the deviation of the steam generation amount is e. The degree of conformity of e to the rule (1) of the antecedent part is a ₃ . Similarly, it is a ₂ for rule (2) and a ₁ for rule (3).

Using the consequent control parameter Y defined in Table 2, the dry damper grate air damper opening control value D _{1 is set} to (1
It is calculated by the equation 1).

[0070]

(Equation 8)

Similarly, the combustion grate front lower air damper control value D ₂ , the combustion grate rear lower air damper control value D ₃ ,
The post-combustion grate below air damper control value D ₄ and the primary air damper control value D ₅ are respectively expressed by equations (12), (13) and (1).
The calculation is performed using the equations (4) and (15).

[0072]

[Equation 9]

[0073]

(Equation 10)

[0074]

[Equation 11]

[0075]

(Equation 12)

Where D ₁₀ is a dry grate lower air damper reference value, D ₂₀ is a combustion grate front lower air damper reference value, D ₃₀ is a combustion grate rear lower air damper reference value, and D ₄₀ is a post combustion grate. The lower air damper reference value, D ₅₀ is the primary air damper reference value. Further, k ₁ is a dry grate below air damper control parameter, k ₂ is a combustion grate front lower air damper control parameter, k ₃ is a combustion grate rear lower air damper control parameter, and k ₄ is a post combustion grate below air damper control parameter. Control parameters,
k ₅ is a primary air damper control parameter.

When adjusting the amount of secondary air together with the amount of primary air, the procedure is as follows. Table 3 shows the rules of fuzzy control in this case.

[0078]

[Table 3]

The rules (1) to (7) in Table 3 are organized for the antecedent part and the consequent part, and the consequent part control parameter Y is determined and shown in Table 4. Y _n1 is positive in increments, Y _n2 is 0, and Y _n3 is negative in decrements.

[0080]

[Table 4]

The suitability a ₁ of the steam generation deviation shown in FIG.
a _2, a _3, and obtains the fitness b _1, b _2, b ₃ measurements c of the exhaust gas in the O ₂ concentrations shown in Figure 3, for antecedent rules in Table 4 (1) to (7) adaptability X ₁ to X ₇ (21) determined by the formula - (27).

[0082]

(Equation 13)

[0083]

[Equation 14]

[0084]

(Equation 15)

[0085]

(Equation 16)

[0086]

[Equation 17]

[0087]

(Equation 18)

[0088]

[Equation 19]

Then, in the consequent reasoning, the rules in Table 4 are used.
Use the consequent part control parameter Y based on (1) to (7)
And the air damper control value D under the dry grate₁ , Burning grate
Front lower air damper control value D_Two, Combustion grate rear lower air duct
Control value D_Three, After-combustion grate below air damper control value
D_Four, Primary air damper control value D_Five, Secondary air damper control
Value D ₆And combustion grate velocity control value S₁ Each (31)
Expression, (32) Expression, (33) Expression, (34) Expression, (35)
The calculation is performed using the equation, the equation (36), and the equation (37).

[0090]

(Equation 20)

[0091]

(Equation 21)

[0092]

(Equation 22)

[0093]

(Equation 23)

[0094]

(Equation 24)

[0095]

(Equation 25)

However, D ₆₀ is the secondary air damper opening reference value,
k ₆ is a secondary air damper control parameter.

Next, regarding the fuzzy control when controlling the combustion grate velocity together with the air amount, first the primary air amount and the combustion grate velocity are controlled, then the primary air amount and the secondary air amount and the combustion grate velocity are controlled. The control will be described.

Table 5 shows the rules for fuzzy control of the primary air amount and the combustion grate velocity.

[0099]

[Table 5]

These rules are organized for the antecedent part and the consequent part, and the consequent part control parameter Y is determined and shown in Table 6.

[0101]

[Table 6]

Based on the membership function shown in FIG.
The calculation of rules (1) to (3)
Goodness of fit of deviation e₁ , A_Two, A_ThreeAsk for. And after
Based on the rules (1) to (3), the dry fire rating was applied based on the reasoning of the section.
Child air damper control value D₁ , Combustion grate front lower air dan
Power control value D_Two, Combustion grate rear lower air damper control value
D _Three, After-combustion grate air damper control value D_Four, Primary air
Damper control value D_FiveAnd combustion grate velocity control value S₁ Each
Expression (41), Expression (42), Expression (43), Expression (44),
The calculation is performed using the equations (45) and (46).

[0103]

(Equation 26)

[0104]

[Equation 27]

[0105]

[Equation 28]

[0106]

(Equation 29)

[0107]

[Equation 30]

[0108]

(Equation 31)

However, D ₁₀ is a dry grate lower air damper reference value, D ₂₀ is a combustion grate front lower air damper reference value, D ₃₀ is a combustion grate rear lower air damper reference value, and D ₄₀ is a post combustion grate. Lower air damper reference value, D ₅₀ is primary air damper reference value, and S ₁₀ is combustion grate velocity reference value. Further, k ₁ is a dry grate below air damper control parameter, k ₂ is a combustion grate front lower air damper control parameter, k ₃ is a combustion grate rear lower air damper control parameter, and k ₄ is a post combustion grate below air damper control parameter. Control parameters, k ₅ is a primary air damper control parameter, and k ₇ is a combustion grate velocity control parameter.

Finally, fuzzy control of the primary and secondary air amounts and the combustion grate velocity will be described. Table 7 shows the rules of fuzzy control in this case.

[0111]

[Table 7]

The rules of Table 7 are summarized for the antecedent part and consequent part, and the consequent part control parameter Y is determined and shown in table 8.

[0113]

[Table 8]

The suitability a ₁ , a ₂ , a _{3 of} the steam generation deviation e shown in FIG. 2 and the suitability b ₁ , b ₂ , b ₃ of the measured value c of the O ₂ concentration in the exhaust gas shown in FIG. Then, the goodnesses of fit X _{1 to} X ₇ for the antecedent parts of the rules (1) to (7) of Table 7 are obtained from the equations (51) to (57).

[0115]

(Equation 32)

[0116]

[Equation 33]

[0117]

(Equation 34)

[0118]

(Equation 35)

[0119]

[Equation 36]

[0120]

(37)

[0121]

(38)

In the consequent reasoning, based on the rules (1) to (7) in Table 8, the dry grate lower air damper control value D ₁ , the combustion grate front lower air damper control value D ₂ , and the combustion grate front lower air damper control value D ₂ The grate rear lower air damper control value D ₃ , the post-combustion grate lower air damper control value D ₄ , the primary air damper control value D ₅ , the secondary air damper control value D _6, and the combustion grate velocity control value S ₁ , respectively. Expression (61), Expression (62), Expression (63), (64)
The calculation is performed using the equation, the equation (65), the equation (66), and the equation (67).

[0123]

[Equation 39]

[0124]

(Equation 40)

[0125]

[Equation 41]

[0126]

(Equation 42)

[0127]

[Equation 43]

[0128]

[Equation 44]

[0129]

[Equation 45]

However, D ₁₀ is a dry grate lower air damper reference value, D ₂₀ is a combustion grate front lower air damper reference value, D ₃₀ is a combustion grate rear lower air damper reference value, and D ₄₀ is a post combustion grate. Lower air damper reference value, D ₅₀ is primary air damper reference value, D ₆₀ is primary air damper reference value, and S ₁₀ is combustion grate velocity reference value. Further, k ₁ is a dry grate below air damper control parameter, k ₂ is a combustion grate front lower air damper control parameter, k ₃ is a combustion grate rear lower air damper control parameter, and k ₄ is a post combustion grate below air damper control parameter. Control parameters, k ₅ is a primary air damper control parameter, k ₆ is a secondary air damper control parameter, and k ₇ is a combustion grate velocity control parameter.

[0131]

[Examples] The primary air amount, its distribution, and the secondary air amount were controlled, and the degree of stability of the amount of steam generated and the degree of effective recovery of combustion energy of dust were examined. The effective recovery degree was evaluated by measuring the CO concentration as an unburned component in the exhaust gas.

4 (a), 4 (b) and 4 (c)
Is a result of applying the control method of the present invention for controlling the primary air amount and its distribution and the secondary air amount.
FIG. 5B and FIG. 5C are test results by a conventional control method performed for comparison. In the conventional control method, the total air amount is not changed, the primary air amount is decreased when the steam generation amount is larger than the target amount, the secondary air amount is increased, and the primary air amount is decreased when the steam generation amount is smaller than the target amount. Control was performed to increase the secondary air amount.

In the embodiment to which the present invention is applied, as shown in FIG.
As shown in, the target steam generation rate is 20 ton / hour.
To ± 1 ton / hour, and it is within the range of Fig. 4 (b).
As shown in, the O ₂ concentration in the exhaust gas is also within the range of about 4 to 7%. At the same time, as shown in FIG. 4C, the exhaust gas CO concentration is also kept low. This shows that the required amount of air is secured at each position in the furnace and that no unnecessary air is blown in, so the combustion of the waste is stable and the energy is recovered as effective steam. ing.

On the other hand, in the conventional control method, the distribution of primary air is
Since combustion has not been performed, combustion is not stable, and Fig. 5 (a)
As shown in, steam for target steam generation rate of 20 ton / hour
The generated amount has dropped to 15ton / hour for 4 hours.
Has happened to twice. Moreover, the amount of steam generated fell
Then, as shown in Fig. 5 (c), the exhaust gas CO concentration is about
It has risen to 60 to 70 ppm. In addition, in FIG.
As shown in the exhaust gas O_Two Concentration also fluctuates greatly with 4-12%
doing.

[0135]

EFFECTS OF THE INVENTION A primary air damper, a dry lower front grate air damper, a combustion grate lower front air damper, so that the steam generation amount falls within a certain range based on the measured value of the steam generation amount.
The primary air amount and its distribution are adjusted by controlling the opening of each of the combustion grate rear lower air damper and the post combustion grate rear lower air damper, or the combustion grate velocity is controlled together with this adjustment. The amount of combustion air is blown into place and the amount of dust is also controlled appropriately. Therefore, it is possible to prevent the useless blowing of air and the supply of dust, and the fluctuation of the steam generation amount is promptly corrected. Also, according to these controls,
Since the O ₂ concentration in the exhaust gas is measured and the amount of secondary air is also controlled, the generation of unburned gas is further suppressed.

As described above, the great effect of the present invention is that the enormous amount of heat energy generated by the incineration process of waste as waste can be efficiently collected and the generation of harmful gas can be suppressed.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a refuse incinerator and its control system for explaining an embodiment of the invention.

FIG. 2 is a diagram showing a membership function of an antecedent part regarding a steam generation amount deviation.

FIG. 3 is a diagram showing a membership function of an antecedent part regarding O ₂ concentration in exhaust gas.

FIG. 4 is a diagram showing a control test result by the combustion control method of the invention.

FIG. 5 is a diagram showing a control test result by a conventional combustion control method.

[Explanation of symbols]

1 Furnace 2 Waste input port 3a Dry grate 3b Combustion grate 3c Post-combustion grate 4 Ash drop port 5 Primary air blower 6 Partition wall 7 Gas mixing chamber 8a Heat exchanger 8b Boiler 9 Secondary air injection port 10a Secondary air Blower 10b Secondary air damper 11 Thermometer 12 Flowmeter 13a Dry grate lower air damper 13b Combustion grate front lower air damper 13c Combustion grate rear lower air damper 13d After combustion grate lower air damper 14 Primary air damper 15 Primary air -Under-grate air damper control means 16 Exhaust gas CO concentration meter 17 Exhaust gas O ₂ concentration meter 18 Secondary air damper control means 19 Combustion grate drive device 20 Combustion grate speed control means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F22B 35/00 F22B 35/00 J

Claims (7)

[Claims] 1. In a combustion control of a refuse incinerator that combusts waste while moving it on a grate and uses the heat of combustion to generate steam, the steam generation amount is measured and the primary air is measured based on the measured value. A method for controlling combustion in a refuse incinerator, which comprises controlling damper openings and controlling individual damper openings under a grate to adjust the air amount. 2. When the steam generation amount is larger than the target amount, the operation (A) is selected, and when the steam generation amount is smaller than the target amount, the operation (B) is selected and the damper is selected. The combustion control method for a refuse incinerator according to claim 1, wherein the opening degree is controlled to adjust the primary air amount. (A) The opening of the primary air damper is reduced, the openings of the front lower air damper of the combustion grate and the lower rear air damper of the combustion grate are decreased, and the air damper of the dry grate and the lower air damper of the post combustion grate are reduced. Operation to increase the opening (B) Increase the opening of the primary air damper to increase the opening of the front lower air damper of the combustion grate and the lower rear air damper of the combustion grate to dry the lower air damper and post-combustion grate Operation to reduce the opening of the air damper under the grate. 3. Adjusting the primary air amount according to claim 2, measuring the O ₂ concentration in the exhaust gas, and increasing the damper opening of the secondary air when the O ₂ concentration in the exhaust gas is low, When the O ₂ concentration in the exhaust gas is high, a method for controlling combustion in a refuse incinerator, which comprises controlling the damper opening for reducing the damper opening of the secondary air to adjust the amount of secondary air. 4. The combustion control method for a refuse incinerator according to claim 1, 2 or 3, wherein fuzzy control is used to control the air damper opening. 5. The primary air amount is adjusted according to claim 2, and when the steam generation amount is smaller than the target amount, the combustion grate velocity is increased, and when the steam generation amount is larger than the target amount. A method for controlling combustion in a refuse incinerator, which comprises controlling a combustion grate speed for reducing a combustion grate speed. 6. The primary air amount and the secondary air amount according to claim 3 are adjusted, and when the steam generation amount is smaller than the target amount, the combustion grate speed is increased so that the steam generation amount is the target amount. A combustion control method for a refuse incinerator, which comprises controlling the combustion grate speed so as to reduce the combustion grate speed when the number is larger than the above. 7. A combustion control method for a refuse incinerator according to claim 5, wherein fuzzy control is used for controlling the air damper opening and controlling the combustion grate velocity.