JP2656879B2 - Automatic combustion control method for incinerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention particularly relates to an automatic combustion control method for automatically controlling a fluidized bed incinerator used for municipal solid waste incineration.

[0002]

2. Description of the Related Art In a conventional fluidized bed refuse incinerator, when automatic combustion control is performed, the temperature of the exhaust gas at the outlet of the furnace is controlled within a set temperature range. Control, keep the furnace pressure at an appropriate negative pressure, mainly control the amount of refuse supplied by quantitative supply control of the amount of combustion treatment, control the exhaust gas temperature at the inlet of the reaction tower such as an electric dust collector within the set temperature range , Exhaust gas O ₂
Many things that are built as detecting and controlling the amount of combustion air that contains the suction amount control of the secondary air to reduce the exhaust gas NO _X, single-loop automatic control six control is independent of the concentration In addition, they are operated and controlled by adjusting each set value in consideration of the waste quality, based on the experience and intuition of the operator (operator).

Separately from this, the flow rate of exhaust gas during operation is calculated, and the calorific value of the waste is calculated using this value, the temperature at the entrance and exit of the cooling tower, and the amount of waste supplied. Combustion control method for automatically setting the amount
No. 130 discloses this.

[0004]

In each of the prior arts described above, it is difficult to reliably and stably burn refuse in accordance with the quality and supply amount of refuse that fluctuates greatly.
Can not adapt the incineration process on planning waste throughput, also not reduced in the exhaust gas NO _X concentration to pollution prevention can not fulfill various such combustion process costs can not be performed optimally economic combustion expensive There is a problem.

The present invention has been made in order to solve such problems, and an object of the present invention is to rationalize waste management, eliminate pollution, promote operation economy, and save labor. It is an object of the present invention to provide a total automatic combustion control system capable of fulfilling the requirements.

[0006]

The present invention has the following configuration to achieve the above object. That is, in the present invention, when continuously incinerating waste in a fluidized bed incinerator, furnace outlet gas temperature control, sand layer temperature control, furnace pressure control, waste supply control, reaction tower inlet exhaust gas temperature control, secondary air exhaust gas The combustion air amount control including the automatic control based on the O ₂ concentration is automatically controlled for each single system. On the other hand, since a linear function relation is established between the waste heat amount and the primary air amount for combustion, the waste heat amount calculates a required primary air quantity based on the calculation result of the target value of the primary air amount for each of predetermined time and change settings, further gas cooling chamber exhaust O ₂ concentration, the furnace exit gas temperature, the gas cooling chamber injection A correction coefficient is set by calculation from each data of the water amount, the fresh water spray water amount in the furnace, the waste heat value, and the target incineration rate, and the correction control for increasing / decreasing the waste supply amount based on the correction coefficient is performed for a time limit of x seconds / y. Characterized in that This is an automatic combustion control method for an incinerator.

[0007]

According to the present invention, the amount of primary air corresponding to the current amount of waste heat is calculated, and the primary air supply amount is corrected every time a predetermined time, for example, less than one hour such as about 20 minutes elapses. from being a more stable combustion operation status is maintained, moreover, since by performing this modification never become disturbance element, the temperature of the exhaust gas, the management of the nO _X concentration is thorough. Further, by causing a correction control to increase or decrease the amount of waste supplied based on the correction coefficient obtained by the calculation in x seconds / y minutes, for example, in a short cycle and a short time period of 1 second every minute, the fluctuation of the amount of heat generated by the waste is changed. , And economical operating conditions are established, and the number of manual operations by the operator is extremely reduced as compared with the related art.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a control system diagram of a fluidized bed incinerator according to an embodiment of the present invention. A fluidized bed incinerator (hereinafter, referred to as an incinerator) 1 includes an air supply unit 2, a sand layer unit 3 where inert sand particles are kept in a floating state, and a free board unit 4 from the bottom. A primary air supply pipe having a pushing blower 5 is connected to the air supply unit 2, and the primary air is press-fitted into the air supply unit 2 so that the supply amount can be adjusted. The rotation of the push-in blower 5 is controlled by an inverter 6 driven by a control unit 7 that performs feedback control using an initial setting value of an air amount setting device 8 and an air amount detected by an air amount detector 9 as input elements. An amount of primary air is supplied into the air supply 2. According to the rotation control of the push-in blower 5, even if there is a change in the thickness of the sand layer or a change in the bypass amount of the air preheater, the primary air amount is controlled so as to maintain a good flow state and maintain an optimum combustion state. .

On the other hand, a secondary air supply pipe having a secondary push blower 10 is connected to the combustion chamber of the free board section 4,
Secondary air is press-fitted into the combustion chamber with a controllable supply.
Secondary forced draft fan 10, based on exhaust gas 0 ₂ concentration exhaust gas 0 ₂ concentration detector 13 has detected, the calculating means 14 for calculating the quantity of secondary air so as to reduce the proper excess air ratio and exhaust gas NO _X value The rotation is controlled by an inverter 11 driven by a control unit 12 that performs feedback control using the output and the air amount detected by the secondary air amount detector 15 as input elements, and supplies a required amount of secondary air into the combustion chamber. .
Combustion is performed at the optimum air ratio in accordance with the rotation control of the forced air blower 10, and automatic adjustment control of the secondary air amount is always performed so that a constant 0 ₂ % can be secured.

A waste supply unit (dusting machine) 16 is connected to a waste supply port of the free board unit 4. Dust feeding machine 16
The amount of dust fed to the waste supply port is automatically controlled by the dust amount control means 17. Dust supply control means 17
Is calculated from a furnace outlet gas temperature output through a furnace outlet gas temperature control means 20 described later, a target incineration amount from the incineration amount setting device 18, a crane charging amount 37, and a waste heat generation amount estimation value described later. An output corresponding to the amount of dust is given to the duster 16 to perform automatic control of the amount of dust based on a quantitative supply control method for the amount of combustion treatment.

A cooling water nozzle 27 is provided in the upper part of the free board section 4, and cooling water is supplied from a cooling water pipe having a flow control valve 33. The flow control valve 33 has a valve opening controlled by a furnace outlet gas temperature control means 20 that outputs a valve opening output based on a furnace outlet gas temperature detected by a furnace outlet gas temperature detector 19, and is sprayed from a cooling water nozzle 27. To control the amount of fresh water spray in the furnace. By controlling the amount of sprayed water, the furnace outlet temperature can be constantly set, for example, from 800 to 9 in normal operation.
It is automatically controlled to enter the range of 00 ° C.

On the other hand, a burner 26 is connected to the sand layer 3 via a combustion air pipe having a flow control valve 34. The flow rate control valve 34 has its valve opening adjusted by a sand layer temperature control means 35 that outputs a valve opening degree based on the sand layer temperature detected by the sand layer temperature detector 36, and the amount of combustion air (heating amount) sent from the combustion air pipe. Control. By controlling the amount of heating,
The sand layer temperature is usually 650 to 8 in normal operation.
It is automatically controlled to enter the range of 00 ° C.

A reaction tower having a gas cooling chamber 21 and an electric precipitator 22, an induction blower 23, and a chimney 24 are connected to an exhaust gas outlet provided at the uppermost part of the free board section 4.
A cooling water nozzle 28 is provided in the gas cooling chamber 21, and cooling water is supplied from a cooling water pipe having a flow control valve 32. The flow control valve 32 has a valve opening controlled by a dust collector inlet gas temperature control means 31 that outputs a valve opening based on the detected dust collector inlet gas temperature, and the cooling water nozzle 2
8 controls the amount of water injected from the gas cooling chamber. By controlling the injection water amount, the exhaust gas temperature at the inlet of the dust collector is automatically controlled so as to always fall within a temperature range of, for example, 250 to 300 ° C. in the normal operation.

A furnace pressure detector 29 for detecting a furnace pressure is provided in an exhaust gas pipe connected to the exhaust gas outlet, and the detected furnace pressure is output to a furnace pressure control means 30. Upon receiving the furnace pressure signal, the furnace pressure control means 30 gives a control output to the inverter 25, and the rotation of the induction blower 23 is adjusted by the inverter 25. By adjusting the rotation of the induction blower 23 in this way, the pressure inside the furnace is automatically controlled to be constant, and the inside of the furnace can be maintained at an appropriate negative pressure.

In the incinerator 1 of the embodiment shown in FIG. 1, the above-described seven automatic control systems are controlled by the control device 38. The control device 38 includes an input port, a central processing unit (CPU), a display unit, and an output port. In addition to individually controlling each of the automatic control systems, the control unit 38 further integrates them to perform data processing. Comprehensive check using the calculation function of the device
Includes an automatic combustion control system for making adjustments.
The automatic combustion control system includes a primary air volume of the air amount detector 9 detects a gas cooling chamber exhaust 0 ₂ concentration exhaust gas 0 ₂ concentration detector 13 has detected, the furnace exit gas temperature detector 1
9, the furnace outlet gas temperature, the gas cooling chamber injection water amount calculated based on the dust collector inlet gas temperature control means 31, and the furnace fresh water spray water amount calculated based on the furnace outlet gas temperature control means 20. And the target incineration rate (incineration amount) set by the incineration amount setting unit 18 as data into the input port, and the CPU calculates the amount of heat generated from the exhaust gas amount and the enthalpy. 0 ₂ concentration, the furnace exit gas temperature, the gas cooling chamber injection water, the furnace Shimizu spray water, waste heating value, thereby calculating each correction coefficient from the data of the target incineration rate. Then, the output port outputs a target value of the primary air amount and a correction value of the waste supply amount.

By providing the above automatic combustion control system, it is possible to perform automatic control of the planned waste disposal amount, automatic control of the optimal air amount, and optimal economic combustion control. That is, the calorific value of the waste is obtained by calculating the exhaust gas amount and its enthalpy, and since a linear function relationship is established between the calorific value of the waste and the primary air amount, the necessary primary air amount is calculated and fixed. The set value of the primary air amount input to the primary air amount control means 7 is changed every time. The gas cooling chamber exhaust 0 ₂ concentration, the furnace exit gas temperature, the gas cooling chamber injection water,
Each process value of the in-furnace fresh water spray water amount, each heat generation amount of the waste, and each data of the target incineration rate are arithmetically processed, and the correction control for each dust amount is performed in a time limit of several seconds per minute.
Next, an example of specific control means in the case of operating while correcting the waste supply amount will be described below. First, the process set values (A to D) and the correction are set for the first and second systems having different correction types based on the following [Table 1] and [Table 2] showing the process values and the correction widths. The coefficient (E, F) is input by keyboard.

[0017]

[Table 1]

[0018]

[Table 2]

In Tables 1 and 2 above, each
In the diagram in the upper frame, the process value (PV) is plotted on the horizontal axis and the plot is plotted on the vertical axis.
Waste supply amount correction line with the waste supply speed (SV) correction%
It is a figure and is displayed in each lower frame as PV in this case .
Has been that gas cooling chamber exhaust 0 ₂ concentration (Gasuhiya 0 _2),
Furnace outlet exhaust gas temperature, furnace spray water flow, gas cooling chamber injection
Water volume (gas-cooled injection water volume), waste heat value, target incineration rate and
Each of the seven process values of the waste input is selected. Follow
Tables 1 and 2 depend on each process value.
This indicates whether only such correction values are output.

Regarding the seven process values,
Explanation of the mode of correction for one "furnace outlet exhaust gas temperature"
I do. For example, a range of 910 ° C (B) to 930 ° C (C)
If, the SV correction output is 0, which is less than 910 ° C.
When [(B)-(A)] is reached, the correction type 2.
Output of up to 10% on the plus side based on
Increase the supply amount) and exceed 930 ° C [(C) ~
(D)], a maximum of 10% correction is output to the minus side.
Give power (increase garbage supply). "Gas cooling
0 ₂ concentration ", the most in the same way also for the" gas cold injection amount of water. "
A correction output of at most 20% and 15% is output.

That is, each process value is corrected between B and C.
The output is 0, the maximum E below B and the maximum F above C.
A positive coefficient is applied, and E and F are
Positive value, negative value, professional
The waste value will increase and the waste supply will increase,
Or decrease it in the screen of [Table 1] and [Table 2].
To set. [Table 1] and [Table 2] are basically the same screen.
As described above, the “gas-cooled O ₂ concentration” is as shown in [Table 1].
Correction type 1. To the "furnace outlet exhaust gas temperature"
Correction type 2. Each adopted
doing.

Here, the set value of the calorific value is shown in [Table 3].
In addition, the set values of the primary pushing air flow rate and the secondary pushing air flow rate are
[Table 4] and [Table 5], and the set values of the furnace pressure increase, the target incineration amount, and the waste input amount are as shown in [Table 6], respectively.

[0023]

[Table 3]

[0024]

[Table 4]

[0025]

[Table 5]

[0026]

[Table 6]

The results are shown in Table 7 below.
Becomes a correction value for the dust feed speed target value (SV value), S V correction value of each item from the gas cooling chamber exhaust O ₂ concentration to refuse loading volumes, "Gasuhiya 0 ₂ concentration" PV = 2.
Since it is 3% (less than 3.0% in Table 1), -2 of the set value E is used.
0%, since the “furnace outlet exhaust gas temperature” is 930 ° C.
%, "Reactor fresh water spray amount" is 0 in this case without correction output
%, And “gas cold injection water amount” is PV = 7976 (75 in Table 2).
00 excess), -15% of the set value F, and
In this case, "amount", "target incineration rate" and "waste input"
The deviation is also 0% without correction output, and in the order of -20, -0,
0, -15, 0, 0, 0%. The total value 35% of the SV correction value is increased or decreased from the previous waste supply speed target value (SV value). Then, when the SV value exceeds ± 10% with respect to the PV value, the amount of waste supplied is increased or decreased. In Table 7, the SV value is 70% of the PV value,
This is 35%, which is obtained by subtracting 35% of the total value.
L = PV−10% ”. In this case, MV
= The output of increase / decrease is “decrease”, that is, the amount of waste supplied is reduced.
Control in the following direction.

[0028]

[Table 7]

By doing so, in the conventional method, each set value of the primary air and the like is corrected at short intervals immediately after one calculation loop is completed from the calculation result of the heat generation amount of the refuse. However, in this case, the change itself may become a disturbance factor, but in the present embodiment, this correction work is performed at a fixed interval time, for example, every 20 minutes, so that there is no disturbance and stable. The driving situation is obtained.
Furnace outlet temperature in the case of performing the automatic combustion control operation, the furnace outlet 0 ₂ concentration (waste input amount 4.71TON / H, incineration of 1
(00%) is shown in FIG. As is apparent from this figure, the changes in temperature and concentration are very small, and it is understood that the heat balance is optimally and stably achieved. On the other hand, the operation state under the same conditions by the conventional manual operation is as shown in FIG. 3, which indicates that both the temperature and the concentration have large fluctuations.

[0030]

As described above, according to the present invention, the control of supplying the required primary air amount is performed by quickly confirming the change in the heat generation amount of the waste, so that the combustion is continued at the optimum air amount. always so it can ensure a flue gas 0 ₂ concentration constant, with pollution prevention can be achieved, it is possible to economically optimal combustion control. In addition, monitoring of various fluctuations in the control process with a constant timepiece and automating the correction of the required amount of waste, as a result, stable operation with less fluctuation can be achieved, and incinerators are used without pollution to maximize efficiency. It is also possible to significantly reduce the frequency of manual operations by the operator.

[Brief description of the drawings]

FIG. 1 is a control system diagram of a fluidized bed incinerator according to an embodiment of the method of the present invention.

[2] the furnace exit exhaust gas 0 ₂ concentration during automatic operation according to an embodiment of the present invention a method in a fluidized bed incinerator, a time diagram of the furnace outlet temperature.

[3] the furnace exit exhaust gas 0 ₂ concentration at the time of a conventional manual operation corresponding to FIG. 2 is a time diagram of the furnace outlet temperature.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fluid bed incinerator, 2 ... Air supply part, 3 ... Sand layer part, 4 ... Free board part, 12 ... Secondary air amount control means, 17 ... Dust amount control means, 18 ... Incineration amount control means, 20 ... Furnace outlet gas temperature control means, 30: furnace internal pressure control means, 31: dust collector inlet gas temperature control means, 35: sand layer temperature control means, 38: control device.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location F23G 5/50 ZAB F23G 5/50 ZABR

Claims (1)

(57) [Claims] 1. In continuous incineration of refuse in a fluidized bed incinerator, furnace outlet gas temperature control, sand layer temperature control, furnace pressure control, refuse supply control, reaction tower inlet exhaust gas temperature control, secondary air exhaust gas O _{(2) While the} combustion air amount control including the automatic control based on the concentration is automatically controlled for each single system, a linear function relationship is established between the waste heat value and the primary air amount for combustion. calculates a required primary air quantity based on the calculation result, changes the setting of the target value of the primary air amount for each of predetermined time, furthermore, the gas cooling chamber exhaust O ₂ concentration, the furnace exit gas temperature, the gas cooling chamber injection water , A correction coefficient is set by calculation from each data of the furnace clean water spray water amount, the waste heat generation amount, and the target incineration rate, and the correction control for increasing / decreasing the waste supply amount based on the correction coefficient is performed in a time limit of x seconds / y minutes. Characterized by Automatic combustion control method of 却炉.