JPH06331123A - Control of amount of combustion air for incinerator for waste - Google Patents

Abstract

PURPOSE:To permit the maintenance of stabilized combustion condition continuously by a method wherein combustion air is controlled so that a difference between an operated air excessive rate and a set reference air excessive rate is corrected. CONSTITUTION:The amount of oxygen in exhaust gas is operated by the sum of the amount of oxygen in combustion air 7 and the amount of oxygen in secondary air 11 to obtain the amount of oxygen consumed by combustion. Next, a primary air excessive rage is operated by dividing the amount of oxygen in the combustion air 7 by the amount of oxygen consumed by combustion, then, the primary air excessive rate is compared with a reference air excessive rate set by the amount of calorific power of waste 3, while the amount of combustion air 7 is controlled so as to eliminate the difference. According to this method, the supply of combustion air 7 can be controlled in accordance with the nature of the waste 3, changing at all times, as well as the complicated relation in the conditions of combustion whereby stabilized combustion condition can be maintained continuously.

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 a combustion air amount for stably burning refuse in a refuse incinerator.

[0002]

2. Description of the Related Art In the operation of a refuse incinerator, controlling the amount of combustion air is an important operating factor. Since it is difficult to properly control the amount of combustion air based on the combustion state, the amount of combustion air that is actually set by the amount of heat generated by waste is the amount of evaporation of the boiler or water spray type in the case of an incinerator with a boiler. In the case of the incinerator, it is corrected and controlled by the heat quantity of the exhaust gas, which is indirectly represented by the spray water quantity.

[0003]

When the amount of combustion air is controlled based on the amount of heat of exhaust gas in order to perform stable combustion control, the combustion situation of dust in the incinerator, excess and deficiency of dust, and secondary air There is a drawback that stable combustion cannot be performed because the amount of air required for combustion cannot be set due to the influence of changes in the furnace outlet temperature due to. The present invention compensates for the conventional defects and supplies a proper amount of air for combustion, thereby supplying a stable amount of dust, that is, satisfying a prescribed processing amount, suppressing the generation of unburned components as much as possible, and maintaining stable combustion. That is the purpose.

[0004]

In order to achieve the above object, the method for controlling the amount of air for combustion in a refuse incinerator according to the present invention comprises:
The waste air is burnt by the supplied combustion air, the secondary air and water are supplied to the generated exhaust gas to reduce the temperature, and the exhaust air is discharged from the flue. A thermometer is installed, the amount of oxygen in the combustion air (converted to a constant temperature) supplied for a certain period of time is calculated from the measured values, and an air flow meter and thermometer are installed in the secondary air supply air duct. Then, determine the amount of oxygen in the secondary air (converted to a constant temperature) that was supplied for a fixed time from the measured values, and install an exhaust gas flow meter, thermometer, oxygen concentration meter, and moisture concentration meter in the flue. The amount of oxygen in the exhaust gas (constant temperature, converted to anhydrous content) discharged in a certain time is calculated from the obtained measured value, and the amount of oxygen in the combustion air and the amount of oxygen in the secondary air The oxygen amount consumed by combustion is calculated by subtracting the oxygen amount of The primary air excess ratio is calculated by dividing the amount of oxygen in the product by the amount of oxygen consumed by combustion, and this is compared with the standard excess air ratio set from the heat value of the waste, and the combustion air amount is used to eliminate the deviation. It is characterized by controlling.

[0005]

[Operation] Burns refuse with the supplied combustion air,
Supply secondary air and water to the generated exhaust gas to reduce the temperature,
In a refuse incinerator that can be discharged from a flue, the amount of oxygen in combustion air (converted to a constant temperature) and the amount of oxygen in secondary air (converted to a constant temperature) that is supplied for a fixed time and a fixed time And the amount of oxygen in the exhaust gas (converted to constant temperature and constant moisture) discharged to.

The amount of oxygen consumed in combustion is obtained by subtracting the amount of oxygen in exhaust gas from the sum of the amount of oxygen in the combustion air and the amount of oxygen in the secondary air, and the amount of oxygen in the combustion air is burned. Calculate the primary air excess rate by dividing by the amount of oxygen consumed by, and compare this with the standard air excess rate set from the heat generation amount of the waste, and control the combustion air amount so that the deviation disappears, Combustion air can be supplied in response to the ever-changing property of waste and the complicated relationship of combustion state, so that a stable combustion state can be continuously maintained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, which is a schematic explanatory view of a refuse incinerator, refuse 3 introduced by a crane 2 from a garbage inlet 1 enters a combustion chamber 5 through a combustion chamber inlet 4. The combustion air 7 preheated by the air preheater 6 is supplied from below the furnace by a forced air blower 8. In the combustion chamber 5, the dust is burned by the combustion air 7 to form ash, and the ash discharge device 1 from the outlet 9 of the furnace.
Sent to 0. The high-temperature exhaust gas generated by combustion is mixed and stirred by the supplied secondary air 11, measured by the furnace outlet exhaust gas thermometer 12, controlled to a specified furnace outlet temperature range, and sent to the gas cooling device 13. To be The cooling water sent from the cooling water spray pump 14 is sprayed to the gas cooling device 13 from the spray nozzle, and the exhaust gas is further reduced in temperature and sent to the air preheater 6, where it is heat-exchanged with the combustion air 7, and the exhaust gas flow meter is measured. 15, air preheater outlet thermometer 1
After passing 6 through the dust collector 17, it is sent to the chimney 19 by the induction blower 18 and discharged to the outside.

Here, the amount of oxygen gas consumed is calculated from the amount of oxygen gas supplied and the amount of oxygen gas discharged in the refuse incinerator to control the primary air excess ratio,
A method that enables rational automatic control of an incinerator will be described. First, the amount of combustion air supplied to the combustion chamber 5 v ₁ (Nm
³ / h) is a combustion air flow meter (blower outlet: wind passage) 23
However, since this combustion air temperature is t ₁ ℃ as measured by the combustion air thermometer 26,
Formula for the combustion air amount v ₂ (Nm ³ / h) at 0 ° C and 1 atmosphere
Calculate according to (1). v ₂ = v ₁ × 273 / (273 + t ₁ ) (1)

The amount of combustion air v ₂ (
Nm ³ / h) multiplied by atmospheric oxygen concentration (21%),
The oxygen amount v ₃ (Nm ³ / h) in the combustion air at 1 atm is calculated according to equation (2). v ₃ = v ₂ × 0.21 (2)

Next, the secondary air flow rate v ₄ (Nm ³ / h) is measured by a secondary air flow meter 22 provided at the air passage (blower outlet). The secondary air temperature is the secondary air. Since it is t ₂ (° C.) as measured by the thermometer 24, the secondary air amount v ₅ (Nm ³ / h) at 0 ° C. and 1 atmospheric pressure is calculated according to the equation (3). v ₅ = v ₄ × 273 / (273 + t ₂ ) (3)

Secondary air quantity v ₅ (Nm
³ / h) multiplied by atmospheric oxygen concentration (21%), 0 ℃, 1
The amount of oxygen in secondary air at atmospheric pressure v ₆ (Nm ³ / h)
Calculate according to (4). v ₆ = v ₅ × 0.21 (4)

Next, the amount v ₇ (Nm ³ / h) of the exhaust gas generated in a certain time by the combustion is measured by the exhaust gas flow meter 15 (often installed behind the dust collector 17). This exhaust gas contains water vapor generated by the combustion of dust and is increased by the water vapor generated by the spray water supplied by the gas cooling device 13. Therefore, the measured value w (%) of the exhaust gas moisture concentration meter 20 becomes Based on this, the dry exhaust gas amount v ₈ (Nm ³ / h) excluding the water amount in the exhaust gas is calculated according to equation (5). v ₈ = v ₇ × (100-w) ÷ 100 (5)

Based on the temperature t ₃ (° C.) measured by the exhaust gas thermometer 16 at the outlet of the air preheater, the dry exhaust gas amount v ₉ (Nm ³ / h) at 0 ° C. and 1 atm is calculated according to the equation (6). . v ₉ = v ₈ × 273 / (273 + t ₂ ) (6)

Based on the oxygen concentration s (%) measured by the exhaust gas oxygen concentration meter 21, the amount of oxygen in the dry exhaust gas v ₁₀ (Nm
³ / h) is calculated according to equation (7). v ₁₀ = v ₉ × s ÷ 100 (7)

Therefore, the sum of the oxygen content v ₃ (Nm ³ / h) in the combustion air at 0 ° C. and 1 atmosphere and the oxygen content v ₆ (Nm ³ / h) in the secondary air at 0 ° C. and 1 atmosphere. The oxygen amount v ₁₀ (Nm ³ / h) in the dry exhaust gas at 0 ° C. and 1 atmosphere is subtracted from the above to obtain the oxygen amount v ₁₁ (Nm ³ / h) consumed by the combustion. v ₁₁ = v ₃ + v ₆ − v ₁₀ (8)

The oxygen amount v ₃ (Nm ³ / h) supplied for combustion at 0 ° C. and 1 atm obtained as described above is 0.
The excess air ratio K ₁ is calculated by dividing by the amount of oxygen consumed v ₁₁ (Nm ³ / h) at 1 ° C and 1 ° C. K ₁ = v ₃ ÷ v ₁₁ (9)

The calculated excess air ratio K ₁ was compared with the standard excess air ratio K ₂ which was set from the heat value of the waste, and the deviation was calculated. The standard excess air ratio K ₂ was calculated from the equation (10). K ₂ = a × Hu + b (10) where Hu is the heat value of the waste and a and b are constants.

When the amount of combustion air was corrected and controlled so that the deviation between the excess air ratio K ₁ and the standard excess air ratio K ₂ was eliminated, it was confirmed that the property of dust and the complicated relationship of combustion conditions would change constantly. It became possible to supply desired combustion air, and it was possible to continuously maintain a stable combustion state.

[0019]

As described above, the present invention continuously calculates the excess air ratio determined by the amount of oxygen consumed by combustion and the amount of oxygen contained in combustion air to generate the heat of dust during combustion. The deviation from the standard excess air ratio set by the amount is calculated, and the combustion air is controlled so as to correct it, so the proper combustion air required for the dust during combustion is supplied, so efficient combustion is achieved. As a result, it is possible to process an appropriate amount of treatment, prevent the generation of unburned substances, and enable rational automatic control of the incinerator.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of an incinerator showing an embodiment of the present invention.

[Explanation of symbols]

1 Waste Inlet 2 Crane 3 Waste 4 Combustion Chamber Inlet 5 Combustion Chamber 6 Air Preheater 7 Combustion Air 8 Forced Blower 9 Reactor Outlet 10 Ash Removal Device 11 Secondary Air 12 Furnace Outlet Exhaust Thermometer 13 Gas Cooling Device 14 Cooling Water spray pump 15 Exhaust gas flow meter 16 Exhaust gas thermometer 17 Dust collector 18 Induction blower 19 Chimney 20 Exhaust gas moisture concentration meter 21 Exhaust gas oxygen concentration meter 22 Secondary air flow meter 23 Combustion air flow meter 24 Secondary air thermometer 26 Combustion For air thermometer

Claims (1)

[Claims] 1. A ventilation air duct for combustion air in a refuse incinerator, in which waste air is burned by the supplied combustion air, secondary air and water are supplied to the generated exhaust gas to reduce the temperature, and the exhaust gas is discharged from a flue. Is equipped with an air flow meter and a thermometer, and the amount of oxygen in the combustion air (converted to a constant temperature) supplied for a certain period of time is found from the measured values, and an air flow meter is installed in the secondary air supply air duct , A thermometer was installed, and the amount of oxygen in the secondary air (converted to a constant temperature) that was supplied for a certain period of time was obtained from the measured values, and an exhaust gas flow meter, thermometer, oxygen concentration meter,
A moisture concentration meter is installed, and the amount of oxygen in the exhaust gas (constant temperature, converted to anhydrous content) discharged for a certain period of time is obtained from the obtained measured value, and the amount of oxygen in the combustion air and the oxygen in the secondary air are obtained. Obtain the amount of oxygen consumed by combustion by subtracting the amount of oxygen in the exhaust gas from the sum of the amount, to calculate the primary air excess rate by dividing the amount of oxygen in the combustion air by the amount of oxygen consumed by combustion,
A method for controlling the amount of combustion air in a refuse incinerator, which comprises comparing this with a standard excess air ratio set from the heat value of the waste and controlling the amount of combustion air so as to eliminate the deviation.