JPH0660732B2 - Combustion control method for multi-stage incinerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is applied to incinerating waste such as sewage sludge in a multi-stage incinerator, in which the temperature inside the oven rises above an allowable temperature and the property of the waste fluctuates. The present invention relates to a combustion control method for a multi-stage incinerator capable of controlling the shift of combustion to the upper stage side and efficiently incinerating with a small amount of fuel used.

(Prior art) Generally, when incinerating waste such as sewage sludge in a multi-stage incinerator, the detected temperature in the combustion zone and the set temperature are compared against changes in the amount of waste, amount of waste water, combustible content, etc. Then, the temperature inside the furnace is automatically controlled by increasing or decreasing the supplied fuel etc. so that the detected temperature matches the set temperature.

However, in particular, when the operation is carried out at less than the planned treatment amount of the treatment plant, for example, in a 100-ton furnace, the amount of waste, the amount of waste water, the amount of combustibles, etc. may change as described below.

Waste amount 25-120t / day Average: 100t / day Waste water amount 70-80% Average: 75% Combustible content 45-65% Average: 55% In such a case, especially in low load operation, the conventional furnace There is a limit to the control only by the internal temperature automatic control, and the combustion position moves upward when the waste amount is 50% or less of the rated value, and as a result, the internal temperature rises above the allowable temperature of each stage in the furnace and The material was often damaged and the service life was shortened.
In addition, if refractory bricks with high fire resistance are used in the dry zone to avoid such problems, the construction cost will increase.

(Problems to be Solved by the Invention) The combustion control method of the present invention is made to solve such a conventional drawback, and suppresses the shift of the combustion position,
An object of the present invention is to provide a combustion control method for a multi-stage incinerator that can efficiently incinerate with a small amount of fuel used.

(Means for Solving the Problems) The first invention made to solve the above problems detects the temperature inside the multi-stage incinerator, and supplies the burner so that the detected temperature and the set temperature match. A combustion control method for a multi-stage incinerator that controls the temperature inside the furnace by increasing or decreasing the amount of heat, when the temperature of the drying zone is detected separately from the above, and the deviation between this temperature and the set temperature of the drying zone is less than the set deviation. Waste is input from the first inlet on the furnace top, and when this deviation exceeds the set deviation, the distribution ratio of the waste is changed according to the magnitude of the deviation, or the single or the second stage or below. It is characterized in that waste is also introduced from a plurality of second inlets.

A second invention made to solve the same problem is to detect the temperature inside the multi-stage incinerator, and increase or decrease the heat supply to the burner so that the deviation between the detected temperature and the set temperature matches. A combustion control method for a multi-stage incinerator that controls the temperature in the furnace, wherein the temperature of the dry zone is detected separately from the above and the deviation between this temperature and the set temperature of the dry zone is calculated, and different stages in the dry zone are calculated. Temperature is detected, the above deviation is multiplied by a predetermined coefficient according to the deviation between the detected temperature difference between the stages and the set temperature difference to calculate the correction deviation, and if this correction deviation is less than the set deviation, Waste is injected from the first inlet on the furnace top, and when this deviation exceeds the set deviation, the waste distribution ratio is changed according to the size of the deviation, and the single or multiple It is characterized in that waste is also input from the second input port of .

Furthermore, in the third and fourth aspects of the invention, the deviation of claim 1 or the correction deviation of claim 2 is further corrected by the amount of waste such as sludge supplied to the multi-stage incinerator or the amount of adhering water, and the value of the waste is used. The feature is that the charging position is changed.

(Example) Below, this invention is demonstrated based on the Example shown in figure.

(1) is a multi-stage incinerator, the top of which is provided with a first input port F ₁ for inputting waste such as sludge, and a second input port F _{2 at} the third stage and below. Is provided. An ash discharge port (3) is provided on the bottom of the furnace. Furthermore, part of the exhaust gas discharged from the exhaust gas discharge port (4) at the top of the furnace passes through the exhaust gas circulation fan (5), the circulation gas control valve (6) and the circulation gas flow meter (7), and the multi-stage incinerator (1) Cooling zone at the bottom of
It is constructed so that it is circulated into (8) through the reflux port (8a).
And preferably a plurality of stages of the combustion zone (10) following the drying zone (9) in the multi-stage incinerator (1), hot air generated in the hot air generating furnace (11) inlet (11a), (11b) Configured to be introduced through.

In this hot air generating furnace (11), the fuel sent by the fuel pump (12) passes through the fuel control valve (13) and the fuel flow meter (14) and is burned in the burner (15) to generate hot hot air. Is. Furthermore, a temperature detector (16) that detects the temperature inside the furnace, that is, the temperature of the combustion zone, is installed at a specific stage above the combustion zone (10), and the measurement signal from the temperature detector (16) adjusts the temperature setting. It is introduced into the combustion control valve (13) through the meter (17). Further, the second temperature detectors (18) and (19) different from the first temperature detector (16) provided in the upper part of the combustion zone are dry zones (9) above the first detection position. Are provided in the third and fourth stages, respectively.

In addition, (20) is a temperature comparison and setting device, (21) is a circulating gas amount controller, and (22) is a waste amount controller. In addition, (23) is a waste flow meter, (24) is a waste moisture meter, (25) is a waste volume calculator, and (2)
6) is a calculator for the amount of attached water.

In such a multi-stage incinerator, the temperature setting controller (17) is instructed to set a temperature such as 600 ° C so that no unburned matter remains in the incineration ash, and the temperature detection provided in the combustion zone (10) is performed. The combustion amount of the burner (15) is controlled by the fuel control valve (13) so that the deviation between the detected temperature detected by the reactor (16) and the set temperature becomes less than the set value. Controlled. Separately from this, the second temperature detector
The temperatures of the dry zone (9) are detected by (18) and (19), and the deviation from the dry zone set temperature preset in the comparison setting device (20) is calculated. If the temperature of the 3rd stage drying zone is 450 ℃
And the temperature detected by the temperature detector (18) is 460 ° C.
, The deviation is 10 ° C, and the set deviation is 50 ° C.
If so, it is within that range. In such a case, the waste is charged from the first charging port F ₁ on the furnace top as in the conventional case.

If the temperature detected by the temperature detector (18) is 520 ° C.
If so, the deviation from the dry zone setting temperature of 450 ° C. becomes 70 ° C., which exceeds the setting deviation of 50 ° C. In such a case, since it indicates that the combustion is moving upward, the comparison setter (20), for example, every 10 to 60 minutes, preferably every 30 minutes to the waste amount controller (22). The correction signal is sent by the waste flow meter (23) and the weight of the waste is calculated by the waste amount calculator (25). In addition to the first input port F ₁ , the second input port of the third stage and below The distribution ratio is increased / decreased and distributed to F ₂ in accordance with the magnitude of the deviation, whereby the transition of combustion to the upper stage side is prevented.

The detection position of the first temperature detector (16) is preferably at the bottom of the dry zone or the top of the combustion zone.

Next, in the second invention, in addition to the above, the temperatures of different stages in the dry zone are detected, and the first invention described above is detected according to the deviation between the detected temperature difference between the stages and the set temperature difference. The deviation between the temperature of the dry zone and the set temperature of the dry zone is multiplied by a predetermined coefficient to calculate the correction deviation. In the embodiment, the second temperature detectors (18), (1) installed in the third and fourth stages of the dry zone (9) are used.
The difference between the temperatures of the third and fourth stages detected respectively in 9) is calculated and compared with the set temperature difference. For example, if the temperature of the third stage is 520 ° C and the temperature of the fourth stage is 650 ° C, the temperature difference between them is 130 ° C. On the other hand, if the set temperature difference is 100 ° C., the deviation between the detected temperature difference of 130 ° C. and the set temperature difference is 30 ° C. In this case, a phenomenon in which the temperature sharply rises in the dry zone, that is, a transition to the upper side of combustion occurs, so the temperature of the dry zone and the set temperature of the dry zone in the embodiment of the first invention described above. The correction deviation is calculated by multiplying the deviation of 70 ° C and the predetermined coefficient corresponding to the deviation of 30 ° C. Then, depending on whether the correction deviation is greater than or equal to the set deviation or less than or equal to the set deviation, the distribution ratio of the waste to the second input ports F ₂ of the third stage and lower is increased in the same manner as in the first aspect of the invention, and combustion is performed. To prevent upward movement of.

As described above, the second invention is an advance over the first invention in that the combustion control is performed in consideration of not only the temperature of the dry zone but also the temperature gradient of the dry zone.

In the third invention, the amount of waste such as sludge supplied to the multistage incinerator is detected by the waste flow meter (23), and the detected waste amount and the waste amount calculator (25) are set in advance. The deviation of claim 1 or the correction deviation of claim 2 is further corrected by the deviation from the amount of waste. For example, when there is a tendency for the amount of waste to be small, there is a high possibility that the combustion stage will move upwards, so this is controlled by increasing the distribution ratio to the second charging port. Then, the position where the waste is put in is changed by the correction deviation as in the first and second aspects.

In the fourth aspect of the invention, the amount of adhered water is calculated based on the amount of waste detected by the waste flow meter (23) and the amount of water detected by the waste moisture meter (24), and the amount of adhered moisture is Calculated as waste x water content. The deviation of claim 1 or the correction deviation of claim 2 is further corrected by the deviation between the adhered water content and the set adhered water content preset in the adhered water content calculator (26). For example, when the amount of adhered water tends to be small, there is a high possibility that the combustion stage will move upward, so the ratio is controlled by increasing the distribution ratio to the second charging port. Then, the position where the waste is put in is changed by the correction deviation as in the first and second aspects. As described above, the fourth invention is a combustion control method that is more advanced than the third invention in that the combustion control is performed in consideration of the amount of water attached to the waste that directly affects the combustion state.

(Effects of the Invention) As described above, the present invention is based on the fact that in addition to the temperature control in the furnace by a normal burner, the temperature of the drying zone or the temperature difference between the stages of the drying zone, and the amount of waste and the amount of attached water By changing the charging position, the combustion can be surely prevented from shifting upward. Therefore, according to the present invention, it is possible to solve the conventional problem that the temperature of the dry zone rises above the allowable value to damage the furnace material and shorten the service life. Further, according to the present invention, since the temperature distribution in the dry zone can be maintained in a preferable state, it is possible to reduce the waste of the amount of fuel used in the entire furnace. Therefore, the present invention, as a combustion control method for a multi-stage incinerator that eliminates the conventional problems, is extremely important in contributing to industrial development.

[Brief description of drawings]

The drawings are sectional views showing an embodiment of the present invention. (9): Dry zone, (10): Combustion zone, (15): Burner, (16): Temperature detector, (18), (19): Second temperature detector, (20): Comparison setting device , F ₁ : first charging port, F ₂ : second charging port.

Claims (4)

[Claims] 1. A combustion control method for a multi-stage incinerator, which detects the temperature in the multi-stage incinerator and controls the temperature in the furnace by increasing or decreasing the amount of heat supplied to the burner so that the detected temperature and the set temperature match. Separately from the above, the temperature of the dry zone is detected, and if the deviation between this temperature and the set temperature of the dry zone is less than the set deviation, waste is injected from the first inlet on the furnace top and this deviation is set. When the deviation is exceeded, the distribution ratio of the waste is changed according to the size of the deviation, and the waste is also input from a single or a plurality of second inlets provided below the second stage, which is a multi-stage incineration system. Combustion control method for furnace. 2. A combustion control for a multi-stage incinerator, which detects the temperature inside the multi-stage incinerator and controls the temperature inside the furnace by increasing or decreasing the amount of heat supplied to the burner so that the deviation between the detected temperature and the set temperature matches. Separately from the above, the temperature of the dry zone is detected, the deviation between this temperature and the set temperature of the dry zone is calculated, the temperature of different stages in the dry zone is detected, and the detected interstage temperature is detected. According to the deviation between the temperature difference and the set temperature difference, the above deviation is multiplied by a predetermined coefficient to calculate a correction deviation, and when the correction deviation is less than or equal to the set deviation, waste is discharged from the first charging port on the furnace top. When the deviation exceeds the set deviation, the waste distribution ratio is changed according to the magnitude of the deviation, and the waste is also injected from the single or plural second injection ports provided in the second stage and below. A combustion control method for a multi-stage incinerator, comprising: 3. The amount of waste such as sludge supplied to the multi-stage incinerator is detected, and the deviation of claim 1 or the correction deviation of claim 2 is further corrected by the deviation between the detected waste amount and the set waste amount, The combustion control method for a multistage incinerator according to claim 1 or 2, characterized in that the position of inputting the waste is changed according to the value. 4. The amount of adhered water is calculated by detecting the amount of waste such as sludge and the amount of water supplied to the multistage incinerator, and the deviation between the amount of adhered water and the set amount of adhered water is used to determine the amount of adhered water. 3. The combustion control method for a multi-stage incinerator according to claim 1 or 2, wherein the deviation or the correction deviation according to claim 2 is further corrected, and the input position of the waste is changed according to the value.