JPS6363808B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an incinerator operating method for stabilizing combustion and effectively treating municipal waste, garbage, and similar waste in a boiler-equipped garbage incinerator. It is.

In general, waste heat boilers have recently been installed in garbage incinerators as a combination system for waste heat utilization in order to effectively utilize the heat energy generated, and the steam generated has become increasingly used. However, because the properties and calorific value of the waste supplied to this incinerator change from moment to moment, the amount generated changes, and the amount of steam generated often fluctuates widely. If this amount of steam generation fluctuates, when planning the use of steam, the plan must be based on the lowest value of the fluctuating amount of steam, which poses a problem because only a portion of the steam generated can be used effectively.

Furthermore, keeping the amount of steam constant also stabilizes the thermal output of the incinerator, so controlling the amount of steam generated at a constant level is extremely important for effective use of steam and stabilization of combustion. It's important.

Conventionally, the flow rate of steam was detected and the amount of combustion air was adjusted to keep the amount of steam generated constant. When the temperature exceeds the set value, the furnace cooling air blower sends cold air into the furnace to control the furnace temperature so that it is always below the set value.

In this method, when the furnace temperature falls below the set value and the furnace cold air is no longer fed, the amount of steam generated naturally decreases and the amount of combustion air increases, but the response depends on the amount of garbage in the furnace. , thickness, etc. Therefore, when a sufficient amount of trash exists in the furnace in a combustible state, increasing the amount of combustion air will quickly ignite the trash, raising the furnace temperature and increasing the amount of steam, so steam amount control is performed. However, even if the amount of combustion air is increased when the amount of dust present in the furnace decreases, the excess air becomes excess and further lowers the furnace temperature, and the amount of steam also decreases, making control uncontrollable. To prevent this from happening, normally we observe the garbage in the furnace, and when there is less garbage, we increase the garbage feeding speed to feed more garbage, and when the amount of garbage increases, we slow down the garbage feeding speed. Even if the waste feeding speed is increased when the furnace temperature is low, the drying speed is slow due to the low temperature inside the furnace, and it takes a considerable amount of time for the furnace temperature to rise. Moreover, if too much air is introduced at that time, the furnace temperature will drop further and there is a risk of extinguishing the fire, which not only causes problems in terms of operability, but also destabilizes the combustion process, resulting in poor efficiency and hindering the utilization of waste heat. There were flaws.

The present invention aims to accurately eliminate these conventional drawbacks, and effectively stabilizes combustion by eliminating the drop in furnace temperature and controlling the waste feeding speed so as not to make it impossible to control the amount of evaporation. The purpose of this project is to provide an economical method that allows for incineration and significantly improves operability.

The present invention provides a waste incinerator with a boiler that burns garbage while supplying combustion air in a combustion chamber in the incinerator, and the furnace cooled air is constantly supplied into the furnace. When controlling the furnace temperature to a constant value by increasing or decreasing the amount of combustion air, and controlling the steam generation amount of the boiler by increasing or decreasing the amount of combustion air, the amount of furnace cooling air is equal to or higher than a set upper limit within a unit time, or
This is a method for controlling the operation of a waste incinerator, which is characterized in that the waste incinerator is operated by adjusting the waste feeding speed when the value falls below a set lower limit value.

An embodiment of the present invention will be described with reference to the drawings.
into the incinerator A, and the stoker drive device 3
The garbage is sent by moving stoker B. The speed of this waste feeding is changed by changing the number of operations per unit time of the input pusher 2 and the stoker B using the waste feeding speed regulator. Air exiting the combustion air blower 4 connected to the incinerator A. The controller 1 is configured to control the steam generation amount of the boiler 8 at a constant level by the combustion air damper 6.
2. For example, the steam is regulated by a steam flow rate controller and sent into the incinerator A. Further, in order to control the furnace temperature of the incinerator at a constant level, the amount of furnace cooling air from the furnace cooling air blower 5 is adjusted by opening and closing the furnace cooling air damper 7 according to instructions from a controller 13, for example, an electronic temperature indicating controller. .

On the other hand, upper and lower limit set values are set for the amount of furnace cooling air, and the time when the amount of furnace cooling air exceeds the upper limit and the time when it falls below the lower limit for each unit time is determined by the calculator 9 via the differential pressure recording flow meter 14. Accumulate each. The setting time is determined in advance, and the setting value of the garbage feeding speed of the stoker B is determined in two ways: a fast value and a slow value.

Then, when the cumulative time during which the amount of furnace cooled air is below the lower limit within a unit time exceeds the set time, the garbage feed speed is changed to a faster value, and the cumulative time during which the amount of furnace cooled air is above the upper limit exceeds the set time. When the value exceeds this value, the garbage feeding speed is controlled to be changed to a slower value.

In this case, when the heat output in the incinerator A increases, the amount of furnace cooling air increases to keep the furnace temperature constant, and the amount of combustion air increases in order to keep the amount of steam generated in the boiler 8 constant. will decrease. Also incinerator A
As the heat output within the furnace decreases, the amount of furnace cooling air decreases and the amount of combustion air increases. Since the amount of furnace cooling air and the amount of combustion air move in opposite directions in this way, the sum of the amount of furnace cooling air and the amount of combustion air remains constant within a certain range.

Furthermore, when the thermal output inside the furnace decreases significantly, the amount of furnace cooling air becomes zero, and the furnace temperature drops, making it impossible to control the amount of steam. With fuels such as oil and gas, when the heat output decreases, fuel can be supplied to quickly recover, but in garbage incinerators, even if the garbage feeding speed is increased, it does not burn immediately, so the heat output is reduced. It takes time for the output to recover, but as mentioned above, if a lower limit is set for the amount of furnace cooling air, and the cumulative amount of time that the amount is below the lower limit increases, increasing the garbage feed rate will cause the amount of furnace cooling air to drop to zero. This can be avoided in advance.

In addition, if the waste feed rate remains high, the heat output will increase and the furnace temperature will rise even when the amount of furnace cooling air reaches the maximum amount, so the cumulative time when the amount of furnace cooling air exceeds the upper limit will increase. By slowing down the garbage feed rate when the amount increases, the garbage feed rate can be switched automatically and combustion can be stabilized.

The upper and lower limit settings are such that the upper limit is 80% of the maximum furnace cooling air amount, and the lower limit is 20% of the maximum value.
It is best to set it as %.

Another way to control the waste feed speed is to set the waste feed speed in three settings: fast, medium, and slow, and then calculate the cumulative time during which the amount of furnace cooling air falls below the lower limit within a unit time. For the above, it is considered a fast value,
Effective results can also be obtained by operating at a slow value while the cumulative time during which the amount of furnace cooling air exceeds the upper limit is longer than the set time, and at other times at an intermediate value.

Note that when the garbage feeding speed is set to two values, one fast and one slow, the speed changes are too sudden, causing the combustion state to become unstable due to constant speed changes. Since the engine operates at a value of , and the speed changes less frequently, combustion is more stable.

The present invention provides a waste incinerator with a boiler that controls the furnace temperature to a constant level by increasing the amount of furnace cooling air while keeping the furnace cooling air constantly being fed into the furnace.
and when controlling the steam generation amount of the boiler by increasing or decreasing the amount of combustion air, when the amount of furnace cooling air becomes more than a set upper limit value or less than a set lower limit value within a unit time, the garbage feeding rate is adjusted. By adjusting the operation, it is possible to keep the furnace temperature constant at all times and control the amount of steam generated by the combustion air to a constant level. By keeping the amount of waste within an appropriate range, we can prevent malfunctions in which the amount of steam generated becomes uncontrollable, ensure stable combustion, and significantly improve the efficiency of incineration processing, resulting in good operability and economy. It has the advantage of being able to improve the efficiency of heat energy and the effective use of thermal energy.

[Brief explanation of drawings]

The drawing is a system explanatory diagram showing an embodiment of the method of the present invention. A... Incinerator, B... Stoker, C... Under-furnace chute, D... Ash discharge chute, 1... Input hopper, 2... Input pusher, 3... Stoker drive device, 4... Combustion air blower , 5... Furnace cold air blower, 6, 6'... Combustion air damper, 7... Furnace cool air damper, 8... Boiler, 9... Arithmetic unit, 10
...Garbage feed speed regulator, 11...Hydraulic unit.

Claims (1)

[Scope of Claims] 1. In a waste incinerator with a boiler that burns while supplying combustion air in the combustion chamber of the waste incinerator, while maintaining the state in which the furnace cool air is constantly fed into the furnace, When controlling the furnace temperature at a constant level by increasing or decreasing the amount of the furnace cooling air, and controlling the steam generation amount of the boiler by increasing or decreasing the amount of the combustion air, the amount of the furnace cooling air is set at a set upper limit within a unit time. A method for controlling the operation of a waste incinerator, characterized in that the waste incinerator is operated by adjusting the waste feeding speed when the value exceeds a value or falls below a set lower limit value. 2. In the garbage feeding step, three types of garbage feeding speeds are determined in advance: a fast value, an intermediate value, and a slow value,
If the cumulative time during which the amount of cold air in the furnace falls below the lower limit set value within a unit time is greater than or equal to the set time, the garbage feed rate will be set to a higher value, and if the amount of cold air in the furnace exceeds the upper limit set within the unit time. The garbage incinerator operation control according to claim 1, wherein the garbage feeding speed is set to a slow value while the cumulative time is longer than a set time, and the garbage feeding speed is operated at an intermediate value at other times. Method.