JPH05118523A - Method of combustion suppression in incinerator and combustion suppressing device - Google Patents

Abstract

PURPOSE:To suppress a regional violent reaction and suppress the formation of clinker by spraying water at the blow-in port of secondary air in an incinerator in order to distribute water particles near the reaction spot where unburned gases and the oxygen in the secondary air react and using the reaction heat for the latent heat absorbed by the water in its evaporation. CONSTITUTION:A water spray nozzle 8 is provided at a secondary air blow-in port 2 used for blowing secondary air into an incinerator 1. Based on a change in the volume of the secondary air that is supplied into the incinerator from the secondary air blow-in port 2 the volume of the water sprayed into the incinerator from the water spray nozzle 8 is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion suppressing method and a combustion suppressing device in an incinerator, and more particularly to a combustion suppressing method and a combustion suppressing device in an incinerator capable of preventing clinker from adhering and growing in the incinerator. Regarding

[0002]

2. Description of the Related Art In recent years, due to changes in lifestyle, the quality of refuse brought to the refuse incinerator has become high in calories. For example, the garbage brought into the municipal waste incinerator was mainly made of kitchen waste and had a lot of water in the past, but recently, due to changes in eating habits, it has been changed to paper mainly made up of a water-less article. .. Due to the high calorie of garbage, clinker has recently come to adhere to the furnace wall of the refuse incinerator.

The combustion pattern in the incinerator is that the amount of primary air supplied is as small as possible necessary for dust to continue burning, and the amount of insufficient air required for complete combustion is blown into the combustion gas as secondary air. There is. Since the amount of waste is high in calories, it is easy to ignite, and the primary air amount is often below the theoretical air amount required for combustion. This means that the amount of primary air called so-called two-stage combustion that keeps the nitrogen oxides in the exhaust gas low is close to or less than the theoretical air amount,
It is also a method to supplement the lack of air with secondary air.

Next, a combustion suppressing method in a conventional incinerator will be described with reference to FIG.

Primary combustion air is blown into the incinerator 20 from the bottom of the furnace. An exhaust gas duct 21 is provided in the upper part of the furnace, and a secondary air blowing port 22 is provided in the middle part of the furnace.
Secondary air is supplied into the incinerator 20 by the secondary air supply pipe 23 connected to the. A control valve 24 is provided in the secondary air supply pipe 23, and the control valve 24 is connected to an oxygen concentration meter 25 for detecting the oxygen concentration in the combustion exhaust gas. The opening degree is controlled based on the.

On the other hand, a water spray nozzle 26 is installed at the top of the incinerator 20, and a water supply pipe 28 having a control valve 27 is connected to the water spray nozzle 26. The operation of the control valve 27 is controlled by a temperature sensor 29 provided at the upper part of the furnace, and thereby the amount of spray from the water spray nozzle 26 is controlled.

[0007]

With the increase in the calorie of waste, the amount of primary air approaches or becomes less than the theoretical amount of air, but the combustion process of waste reacts with oxygen in the air while gasifying. Since it takes time to go, there is a considerable unburned gas condition until the secondary air is blown in.

The unburned gas violently reacts with the residual oxygen in the primary air and the oxygen in the secondary air due to the disturbance of the exhaust gas due to the blowing of the secondary air. This violent reaction occurs in the vicinity of the secondary air blowing port 22, and the temperature in this vicinity is 100 at a stroke.
The temperature rises to over 0 ° C. Then, the ash content in the dust floating in the exhaust gas is softened at around 1000 ° C. and adheres to the furnace wall as a clinker.

Conventionally, the temperature inside the furnace changes as a result of the increase / decrease in the secondary air amount, and the result of intense combustion is captured and water spray is carried out by operating the water spray nozzle 26 at the top of the furnace, and near the top of the furnace. The temperature was kept at, for example, 950 ° C. or lower.

However, in this method, there is a problem that fine ash in the exhaust gas reaches a temperature around 1000 ° C. where the ash adheres to the furnace wall as a clinker at a partly high temperature due to vigorous combustion. .. Further, what adheres to the furnace wall as a clinker also adheres to a sensor for controlling the secondary air (for example, oxygen concentration sensor 25) or a sensor for controlling the furnace top temperature (temperature sensor 29) and grows uncontrollable. There was a problem that caused the condition.

Further, there is a problem that the clinker may adhere and grow in the exhaust gas duct 21 at the outlet of the incinerator, and the exhaust gas duct 21 may reach a closed state, so that the combustion may be stopped.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to carry out water spraying on the inlet of secondary air in the furnace, so that unburned gas and oxygen in the secondary air are oxygenated. Combustion control method in a combustion furnace capable of suppressing local reaction and suppressing clinker formation by using water heat to evaporate latent heat of water by causing water particles to exist in the vicinity when and react with And a combustion suppression device.

[0013]

In order to achieve the above-mentioned object, a method for suppressing combustion in an incinerator according to the present invention is provided with a water spray device at a secondary air blowing port for blowing secondary air into the incinerator. The amount of spray water sprayed from the water spray device into the furnace is changed based on a change in the amount of secondary air supplied from the secondary air blowing port into the furnace.

Further, the combustion suppressing device in the incinerator according to the present invention is provided with a secondary air blowing port for blowing secondary air into the incinerator, and water is sprayed into the furnace provided in the secondary air blowing port. A water spray device for controlling the amount of spray water to be sprayed from the water spray device into the furnace based on a change in the amount of secondary air supplied from the secondary air blowing port into the furnace. It is characterized by having.

[0015]

The present invention is configured as described above, and when the amount of secondary air increases or decreases depending on the state of the exhaust gas coming out of the fluidized medium, the change in the amount of secondary air is detected and the secondary air By changing the amount of spray water from the water spray nozzle installed at the blow-in port and increasing the amount of secondary air and making the disturbing state more intense, the amount of spray water is increased as much as possible, and the part of the exhaust gas that is the clinker generation condition It is possible to prevent a high temperature. As a result, generation of clinker on the furnace wall of the combustion furnace can be eliminated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a combustion suppressing method and a combustion suppressing device in an incinerator according to the present invention will be described below with reference to FIG.

FIG. 1 is a schematic view showing the basic structure of a combustion suppressing device in an incinerator, in which reference numeral 1 is an incinerator. Primary combustion air is supplied to the inside of the incinerator 1 from the bottom thereof. An exhaust gas duct 1a is provided in the upper part of the incinerator 1, and a secondary air blowing port 2 is installed in the middle part of the furnace, and a secondary air supply pipe 3 is provided in the secondary air blowing port 2. It is connected. A control valve 4 is interposed in the secondary air supply pipe 3, and the control valve 4 controls the amount of secondary air blown into the incinerator. Further, the control valve 4 is connected to oxygen concentration meters 5 and 6 for detecting the oxygen concentration in the combustion exhaust gas in the furnace, and the control valve 4 is connected based on the detection values of the oxygen concentration meters 5 and 6.
Is controlled so that the amount of secondary air blown from the secondary air blow-in port 2 is controlled. It is preferable to control the control valve 4 based on the detection value of the oxygen concentration meter 5 installed near the fluidized bed on the upstream side of the secondary air blowing port 2.

On the other hand, a water spray nozzle 8 is installed at the secondary air blowing port 2, and a water supply pipe 9 is connected to the water spray nozzle 8. Further, the water supply pipe 9 has a control valve 10
The control valve 10 is provided with a secondary air supply pipe 2
It is connected to a flow meter 11 that measures the flow rate of the secondary air in the inside, and is also connected to a temperature sensor 12 that measures the exhaust gas temperature in the incinerator 1.

[0019] However, since waste is a collection of various miscellaneous substances, in a fluidized bed in which the calorific value varies and the combustion speed is fast, the waste gas is gasified in the fluidized medium and the oxygen in the exhaust gas discharged from the fluidized medium is discharged. There are variations in quantity. That is, there is a variation in the amount of oxygen deficiency, and the required amount of secondary air that compensates for this also changes. When the amount of secondary air increases, the blowing speed into the furnace increases, the disturbance state of the exhaust gas becomes large, and the exhaust gas temperature in that part rises rapidly due to the rapid oxidation reaction.

In the present invention, the state of the exhaust gas coming out of the fluid medium is detected by the oxygen concentration meters 5 and 6, and the control valve 4 is controlled based on this detection signal to blow the secondary air into the furnace. Increase or decrease. Then, the change in the secondary air amount is captured by the flow meter 11, and the control valve 10 is controlled to change the amount of spray water from the water spray nozzle 8 installed in the secondary air blow-in port 2. As the amount of air increases and the disturbed state becomes more severe, the amount of spray water from the water spray nozzle 8 is increased as much as possible, and it is possible to prevent the exhaust gas, which is a condition for producing clinker, from partially increasing in temperature.

The above control is performed when the temperature sensor 12 detects a predetermined temperature (800 to 1000 ° C.). That is, when the temperature in the incinerator reaches 800 to 1000 ° C. (this temperature is selected depending on the quality of dust), the water spray nozzle 8 is operated to spray water into the furnace.

In the present invention, water is sprayed from the water spray nozzle 8 to the secondary air blowing port 2 so that when the unburned gas reacts with oxygen in the secondary air, water particles are present around it. By using the heat of reaction as the latent heat of vaporization of water, the local violent reaction is suppressed and the production of clinker is suppressed. Particularly in the case of a fluidized bed furnace, the primary air is only the air that keeps the fluidized medium flowing, and the higher the calorie of the waste, the less the oxygen in the combustion gas that leaves the fluidized medium. Therefore, when secondary air is blown into the freeboard section, a vigorous oxidation reaction is carried out to the extent that a flame appears to be jetting from the blowing port. The higher the calorie, the more the clinker adheres near the secondary air inlet.
However, according to the present invention, by controlling the control operation by increasing / decreasing the water spray amount in accordance with the increase / decrease in the secondary air amount at the secondary air blowing port 2, oxygen is required and the secondary air amount is increased, and blown out. Even if the wind speed rises and a disturbing state occurs, the entrained spray water evaporates to remove a part of the combustion heat, so that the intense combustion is suppressed. Therefore, it is possible to prevent the clinker from adhering to the furnace wall of the incinerator.

In the embodiment shown in FIG. 1, an oxygen concentration meter is installed to detect the state of the exhaust gas, but a carbon monoxide concentration meter may be installed instead of the oxygen concentration meter, and the luminous intensity of the exhaust gas is measured. You may install the photometer which measures.

Next, FIG. 2 shows the results of a comparative test conducted between the conventional combustion suppressing method and the combustion suppressing method of the present invention.

FIG. 2 (a) shows the temperature in the incinerator in the conventional combustion suppressing method, the lower curve shows the furnace temperature near the furnace top, and the upper curve shows the temperature near the secondary air inlet. Indicates the furnace temperature. As can be seen from the figure, the temperature reaches 1000 ° C. near the secondary air inlet where clinker may be generated.

FIG. 2 (b) shows the temperature inside the incinerator in the combustion suppressing method of the present invention, the lower curve shows the temperature inside the secondary air blowing port, and the upper curve shows the vicinity of the furnace top. The temperature in the furnace is shown. As is clear from the figure, according to the present invention, the furnace temperature is maintained at around 800 ° C for operation.

[0027]

As described above, according to the present invention, when the amount of secondary air increases or decreases depending on the state of the exhaust gas coming out of the fluidized medium, the change in the amount of secondary air is detected and the secondary air is detected. The amount of spray water from the water spray nozzle installed at the air inlet is changed, and the amount of spray water is increased as much as the amount of secondary air increases and the disturbing state becomes more intense. Partial high temperature can be prevented. As a result, generation of clinker on the furnace wall of the combustion furnace can be eliminated.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a combustion suppressing method and a combustion suppressing device in an incinerator according to the present invention.

FIG. 2 is a diagram showing the results of a comparative test between a conventional combustion suppression method and the combustion suppression method of the present invention.

FIG. 3 is an explanatory view showing a combustion suppressing method and a combustion suppressing device in a conventional incinerator.

[Explanation of symbols]

 1 Incinerator 2 Secondary Air Inlet 3 Secondary Air Supply Pipe 4 Control Valve 5, 6 Oxygen Concentrator 8 Water Spray Nozzle 9 Water Supply Pipe 10 Control Valve 11 Flowmeter 12 Temperature Sensor

Claims (4)

[Claims] 1. A water spraying device is provided at a secondary air blowing port for blowing secondary air into the incinerator, and based on a change in the amount of secondary air supplied from the secondary air blowing port into the furnace. A method for suppressing combustion in a combustion furnace, comprising changing the amount of spray water sprayed from the water spray device into the furnace. 2. The water spray device detects the temperature in the incinerator, and when the temperature exceeds a predetermined temperature, based on a change in the amount of secondary air supplied into the furnace from the secondary air blowing port, The method for suppressing combustion in an incinerator according to claim 1, wherein the amount of water sprayed into the furnace is changed. 3. The oxygen concentration of the combustion exhaust gas upstream of the secondary air blowing port is detected to increase or decrease the secondary air amount, and the amount of spray water at the secondary air blowing port is controlled by the amount of increase or decrease. The method for suppressing combustion in an incinerator according to claim 1. 4. A secondary air blowing port for blowing secondary air into the incinerator, a water spraying device provided at the secondary air blowing port for spraying water into the furnace, and the secondary air. Combustion in an incinerator characterized by comprising a control device for changing the amount of spray water sprayed from the water spray device into the furnace based on a change in the amount of secondary air supplied from the blow-in port into the furnace Suppressor.