JP2973154B2 - Combustion control method for incinerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control method for an incinerator used for minimizing generation of harmful substances such as CO, NOx and dioxin.

[0002]

2. Description of the Related Art Conventionally, incinerators for burning refuse are:
A pit-and-crane-type refuse receiving unit that accumulates garbage in a garbage pit once and then throws the garbage into a hopper by a crane; The apparatus is provided with a grate dust moving device that stirs and moves inside the incinerator, and an air conditioning device that divides the amount of primary combustion air distributed to the grate dust moving device into each of the drying zone, the combustion zone, and the post-combustion zone.

[0003] The refuse in the hopper moves in the incinerator while being stirred by the grate refuse moving device in the incinerator by the dust supply device, is dried in the drying zone, and is burned in the combustion zone and the post-combustion zone. At this time, a predetermined amount of primary combustion air is distributed by the primary air volume control device to each zone below the grate of the grate waste moving device, and is introduced into the incinerator. The secondary combustion air is pressurized by a secondary combustion blower,
A predetermined amount of air is introduced into the furnace.

The refuse sent into the incinerator by the dust supply device is moved and dried by the grate refuse transfer device,
It is burned in the central part of the furnace, ignited by post heat, and the unburned matter is further burned and discharged as ash. Meanwhile, it takes about one hour to complete the combustion.

[0005] Therefore, when a change in the quality of waste is sensed based on the combustion situation, about one hour of waste is already in an excessive amount or an insufficient amount of waste and has entered the furnace. It has become difficult. In order to solve the problem of the combustion control, various automatic combustion control methods described in the following items have been considered.

[0006] The thickness of the refuse (the thickness of the refuse on the grate of the grate refuse moving device) is measured, and the refuse feed speed is adjusted.

[0007] The refuse burn-off point is measured and the refuse feed speed is adjusted.

[0008] The apparent specific gravity is calculated based on the amount of waste input (weight measurement of the waste input crane) and the amount of waste moved by the waste hopper, and the waste quality (assuming that the water content is high when the specific gravity is low and the water content is low when the specific gravity is low) is calculated. Adjust the garbage feed rate.

If the quality of the garbage is known, the lower calorific value of the garbage (the calorific value of water vaporization and the higher calorific value) or the higher calorific value (the calorific value actually generated when the garbage is burned) is calculated. Adjust the feed speed (for example, Japanese Patent Publication 5-17
No. 453).

[0010]

However, the control method described in the above and the above items is a result of combustion, and is not preferable as a control method because about one hour of refuse is contained in the furnace. Is practically difficult.
In the control method described in the item, the apparent specific gravity (specific gravity when gently placed) itself is compressed in the garbage hopper, and the volume changes due to the garbage shape, and the measurement itself becomes inaccurate. Not just. The control method described in the item can measure the total combustion energy ((calorific value) x (combustion amount)), but the calorific value itself is only an estimation and is inaccurate. For the reasons described above, none of the control methods is a fundamental solution.

[0011] Therefore, an object of the present invention is to balance the amount of waste input into the incinerator and the amount of burning waste, thereby increasing the amount of waste retained in the incinerator and withering the waste (in the incinerator). Burned all, no more fuel garbage)
It is an object of the present invention to provide a combustion control method for an incinerator, which prevents the occurrence of a combustion and improves control characteristics.

[0012]

According to the present invention, a pit-and-crane-type refuse receiving section in which refuse is once accumulated in a refuse pit and then charged by a crane, and refuse received from the refuse receiving section are provided. A dust supply device to be supplied to the incinerator, a grate refuse moving device for stirring and moving the refuse in the incinerator, and a method of drying, burning, and post-combusting the amount of combustion air supplied to the grate refuse transfer device. An incinerator combustion control method for controlling the combustion of the incinerator, comprising detecting the amount of the combustion air, the oxygen concentration in the exhaust gas, and the temperature of the exhaust gas at the outlet of the incinerator. The difference between the amount of waste currently burning by the calculation and the amount of waste measured by the crane is calculated, and the amount of combustion air is calculated based on the amount of change in the amount of waste held in the incinerator.
A combustion control method for an incinerator characterized by performing correction control of a dust amount of the dust feeding device, a grate dust moving speed of the grate dust moving device, and a combustion air diverting ratio to each zone. Can be

[0013]

According to the combustion control method of the incinerator of the present invention, the amount of waste currently burning is calculated from the air flow rate, the oxygen concentration in the combustion gas, and the gas temperature at the furnace outlet by the combustion control. Based on the difference between the integrated value and the integrated value of the amount of waste put into the furnace by the crane, the amount of garbage held on the grate of the grate waste moving device (remaining fuel in the incinerator) is calculated and the grate Adjust the feed speed of By the combustion control method of this incinerator,
The position of the combustion flame in the incinerator is stabilized, and the generation of CO, NOx, dioxin and the like is minimized.

In the control method based on the hold amount of the waste, if the amount of the currently burning waste and the amount of the injected waste are balanced, an increase in the amount of waste retained in the incinerator and the withering of the waste (all in the furnace). The control characteristic is improved since the fuel can be prevented from burning and garbage no longer serving as fuel).

[0015]

Next, an embodiment of a combustion control method for an incinerator according to the present invention will be described with reference to FIGS.

Referring to FIG. 1, in the incinerator of this embodiment, the refuse 51 carried in is once accumulated in a pit 52, and then put into a hopper (refuse receiving part) 54 by a crane (crane bucket) 53. Pit and crane system.

The incinerator includes a dust supply device 55 for supplying the refuse received in the hopper 54 into the incinerator, a grate refuse transfer device 56 for stirring and moving the refuse in the incinerator, and a primary combustion air amount. An air flow control device is provided for diverting air into each of a drying zone, a combustion zone, and a post-combustion zone.

The refuse in the hopper 54 is supplied to a dusting device 55
After being moved in the incinerator while being agitated by the grate refuse moving device 56 in the incinerator, it is dried and burned. The primary combustion air is pressurized by the primary combustion blower 57, and a predetermined amount of air is distributed to each zone below the grate by the air volume control device and introduced into the incinerator. The secondary combustion air is pressurized by the secondary combustion blower 58, and a predetermined amount of air is introduced by the air volume control device.

As shown in FIG. 2, the steam generation amount constant control by the boiler 59 to keep the operation generated steam amount for the turbine constant is performed by the primary combustion air amount adjusting device A and the secondary combustion air amount adjusting device. B controls to keep the total combustion gas calorific value constant. The zone air distribution in the lower part of the grate of the grate refuse moving device 56 is performed by a manual setting device, and Zone (zone) 1 air for correcting the distribution amount of the combustion air in the drying zone, the combustion zone, and the post-combustion zone. Setting 13, Zone 2 Air setting 14, Z
One (zone) 3 air setting 15 and Zone (zone) 4 air setting 16 are distributed at preset air amounts.

The amount of waste, which is the fuel, is supplied to the dust supply device 5.
The dust feeding speed is adjusted by the dust feeding speed adjusting device 30 for adjusting the dust feeding speed of No. 5, and the dust is fed into the incinerator. The refuse introduced into the incinerator moves in the incinerator while being stirred by the on-grate refuse moving speed adjusting device 31, and is dried and burned.

However, with such a control method, the combustion in the incinerator is not stabilized, and the combustion rapidly increases or decreases, resulting in a large variation in the amount of generated steam and an increase in CO, NOx and dioxin. The main factor is the fluctuation of the amount of waste that stays in the incinerator. In other words, when the waste quality (wet waste) decreases, the amount of waste remaining in the incinerator increases, and the amount of combustion heat required to dry the waste becomes insufficient. It will be. In addition, if there is waste (dry waste), combustion is promoted, and thereafter, the amount of staying waste in the incinerator is reduced, the waste becomes dead, and the calorific value of steam rapidly decreases.

In order to prevent the above-mentioned defects, correction control is performed by a dust hold amount calculation corrector C. The incinerator has a primary combustion air amount detector 1 for detecting a primary combustion air amount, a secondary combustion air amount detector 2 for detecting a secondary combustion air amount, and a temperature of a gas discharged from a furnace outlet of the incinerator. Is provided with a furnace outlet exhaust gas temperature detector 3 for detecting the exhaust gas, an exhaust gas oxygen concentration detector 5 for detecting the oxygen concentration of the exhaust gas, and a refuse input weight detector 8 for detecting the input weight of the refuse input by the crane 53. ing.

The results detected by the primary combustion air amount detector 1 and the secondary combustion air amount detector 2 are calculated based on the total combustion air operation unit 4, the total generated heat amount operation unit 6, and the inside of the furnace of the garbage hold amount operation corrector C. The calculation is performed by the combustion waste amount calculation unit 7, the waste hold amount calculation unit 10, and the combustion air amount correction calculation unit 11, and is output to the primary and secondary combustion air amount correction calculation unit E. At this time, the furnace exhaust gas temperature detector 3 and the exhaust gas oxygen concentration detector 5 detect
It is calculated by the total generated calorie calculation unit 6. The detection result of the garbage input weight detector 8 is calculated by the integration and storage calculation unit 9 and output to the comparison calculation unit 10. The comparison operation unit 10 is output to the secondary combustion air amount correction unit 11, the lower furnace combustion air amount correction operation unit 12, and the feed speed correction operation unit 25.

The detection result of the furnace exhaust gas temperature detector 3 is calculated by a secondary combustion air correction calculator D. The calculation result of the furnace lower combustion air amount correction unit calculation unit 12 is output to the correction calculation unit 17, and the air amount adjustment device 21 is adjusted by the Zone 1 air amount setting 13. The calculation result of the feeding speed correction calculating unit 25 is corrected and calculated by the correction calculating unit 28, and the feeding speed is corrected by the feeding speed adjusting device 30.

Further, the dust supply speed correction calculating section 25 is calculated by the correction calculating section 29 by the on-grate dust moving speed setting 27 and corrects the on-grate dust moving speed by the on-grate dust moving speed adjusting device 31.

The setting of the Zone 2 air setting 14 is calculated by the correction calculation unit 18,
Control. Zone 3 air setting 15
It is calculated by the correction calculation unit 19 and controls the air amount adjusting device 23. Zone (zone) 4 is calculated by the correction operation unit 20 and controls the air amount adjusting device 24.

In the combustion control method of the incinerator using the above-mentioned garbage hold amount calculation corrector C, the present combustion calculation is performed based on the primary combustion air amount and the secondary combustion air amount, the oxygen concentration in the exhaust gas, and the exhaust gas temperature at the furnace outlet. The amount of burning refuse is calculated, and the fluctuation amount of the refuse hold amount on the grate of the grate grate refuse moving device 56 is calculated based on the difference between the integrated value and the refuse amount measured by the crane 53. By this control method, the primary combustion air amount, the secondary combustion air amount, the dust supply device 5
In addition to adjusting the amount of dust supplied and the moving speed of the grate dust of the grate device 56, correction control of the combustion air flow ratio to each zone is performed.

Such a control method is necessary for an incinerator in which it is desirable to keep a constant amount of steam generated for operation of a turbine, particularly in a large furnace with a generator.

[0029]

As described above, as described in the embodiments,
According to the present invention, based on the hold amount in the furnace, the air amount in the furnace, the flow ratio of each zone (increase the air amount in the drying zone for low-quality waste, and increase the air amount in the drying zone for high-quality waste) Combustion can be stabilized by adjusting the amount of refuse, the amount of refuse, stirring of grate refuse, and the moving speed to appropriate values, and the amount of unburned material remaining in the incinerated ash is reduced, The generation of clinker and the drying of the grate due to the rise can be prevented, and the generation of CO, NOx, and dioxin can also be suppressed.

Further, by balancing the amount of waste currently burning and the amount of waste to be input, the amount of waste retained in the incinerator increases, and the waste withers (the entire furnace burns and the fuel is no longer used). (A state in which no garbage is removed), so that the control characteristics are greatly improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of an incinerator and a main control part of the present invention.

FIG. 2 is a block diagram showing an embodiment of a combustion control method for an incinerator according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary combustion air detector 2 Secondary combustion air detector 3 Furnace outlet exhaust gas temperature detector 4 Total combustion air amount calculation unit 5 Exhaust gas oxygen concentration detector 6 Total calorific value calculation unit 7 Furnace combustion waste calculation unit 8 Garbage injection Weight detection unit 10 Garbage hold amount calculation unit 30 Dust feeding speed adjustment device 31 Dust moving speed adjustment device on grate 52 Dust pit 53 Crane 55 Dust feeding device 56 Grate dust moving device

Claims (1)

(57) [Claims] After accumulating garbage once in a garbage pit,
A pit-and-crane-type refuse receiving unit that is charged by a crane, a dust supply device that supplies refuse received from the refuse receiving unit into an incinerator, and a grate trash transfer that stirs and moves the refuse in the incinerator. A combustion control method for an incinerator, comprising: a device and an air amount adjusting device for diverting the amount of combustion air supplied to the grate refuse moving device to each of drying, burning, and post-combustion zones, and controlling combustion in the incinerator. At
The combustion air amount, the oxygen concentration in the exhaust gas, and the exhaust gas temperature at the outlet of the incinerator are detected, and the difference between the amount of waste currently burning by the combustion calculation and the amount of waste measured by the crane is calculated. Based on the fluctuation amount of the refuse hold amount in the furnace, the combustion air amount, the supply amount of the dust supply device, the grate refuse movement speed of the grate refuse transfer device, and the ratio of the combustion air flow to each zone. A combustion control method for an incinerator, comprising: