JPH0526423A - Waste material combustion device and combustion method - Google Patents

Abstract

PURPOSE:To restrict a primary combustion, limit an occurrence of hot heat and prevent a clinker of substance of low melting point from being generated by a method wherein combustion discharged gas is mixed with primary combustion air, secondary air is supplied to a free board part of an incinerator and some variable substances contained in the waste material are recovered. CONSTITUTION:Waste materials to be ignited are supplied by a supplying feeder 1 to a fluidized bed incinerator 2, primary combustion air is fed from a blower 3 into a window box 12 at a bottom part of a fluidized bed incinerator 2 at a rate of more than 20% of the primary air and the discharged gas after its processing is fed from a blower 4 and mixed to each other. In turn, secondary air is supplied from a secondary air fan 5 to a nozzle arranged at an upper part of a free board and oxidization combustion is promoted there. In the case that mixed substances of low melting point are melted to generate clinker, the amount of discharged gas is increased and a combustion temperature of the substances is decreased so as to prevent the clinker from being generated. Non-ignited substances accumulated at a bottom part of the furnace are cooled by an ash cooling device 6, then some valuable substances such as aluminum or the like are recovered by a valuable material recoverying device 7 after cooling it with the cooling device 6. Accordingly, a rate of occurrence of the clinker may be decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste incinerator and a method for incinerating waste such as municipal waste and industrial waste.

[0002]

2. Description of the Related Art As an example of a conventional waste incinerator, a flow in a fluidized bed furnace is shown in FIG. Waste is supply feeder 1
More supplied to the fluidized bed incinerator 2. The unburned (reducing) gas from the fluidized bed incinerator 2 is completely burned in the secondary combustion furnace 13. The temperature of the fluidized bed is controlled only by the amount of fluidizing (primary) air. The combustion exhaust gas is recovered (or cooled) by the heat recovery device 8, and the exhaust gas fan 9 is used by the exhaust gas treatment device 10.
After being sent to, the exhaust gas is processed and discharged from the stack 11. In the figure, 3 is a fluidized air blower, and 5 is a secondary air fan.

[0003]

The above conventional incinerator has the following problems to be solved.

That is, in the conventional incinerator, only the primary air for maintaining the fluidization is supplied to the fluidized bed blower, and if the calorific value of the waste is high even if the suppression combustion is intended, the fluidized bed is blown. Part temperature rises. For this reason, if a substance with a low melting point such as aluminum is mixed in the waste, it melts in the fluidized bed to generate clinker, which makes it impossible to flow, making continuous operation difficult for a long time. In addition, when a low boiling point substance was contained, there was a problem that this substance solidified and adhered in the subsequent heat recovery section, causing trouble.

On the contrary, even if two-stage combustion of reduction + oxidation is attempted in the fluidized bed, the oxidizing atmosphere is strong and harmful substances such as chromium are oxidized only by supplying air, and harmful hexavalent chromium is suppressed. Is difficult to do.

In order to solve the above problems, the present invention suppresses primary combustion by mixing 20% or more of exhaust gas into primary air,
It is an object of the present invention to provide a waste incinerator and a method for incinerating the same, which suppresses generation of high heat and prevents a low melting point substance such as aluminum from producing a clinker.

[0007]

As a means for solving the above problems, the present invention is to provide a waste incinerator and a waste incineration method described in (1) and (2) below. (1) In an incinerator for waste including toxic substances such as municipal waste and industrial waste, exhaust gas supply means for mixing combustion exhaust gas into primary combustion air and secondary air supply to the freeboard part of the incinerator A waste incinerator comprising a means and a recovery device for recovering valuable materials such as aluminum contained in the waste. (2) Since the oxygen concentration is reduced and the waste is primarily burned in a reducing atmosphere, the combustion exhaust gas is 20% of the total air amount.
A waste incineration method characterized by mixing the above, burning the waste as primary air, and then supplying secondary air to the freeboard section to completely burn unburned components.

[0008]

Since the present invention is constructed as described above, it has the following actions. (1) In the structure of (1) above, since the exhaust gas supply means for mixing the combustion exhaust gas into the primary combustion air of the waste is provided, the oxygen concentration in the primary combustion air can be controlled by controlling the mixing amount of the combustion exhaust gas. Can be controlled, and high temperature combustion of waste can be suppressed, so that clinker does not occur.

Further, since the secondary air supply means for the freeboard portion of the incinerator is provided, the secondary combustion can be completed in the incinerator, so that the secondary combustion furnace is not required.

Further, since a recovery device for recovering valuable materials such as aluminum is provided, a factor that causes a low temperature melting point substance such as aluminum to stay in the furnace and cause clinker is eliminated. (2) In the configuration of (2) above, the combustion exhaust gas is mixed at a rate of 20% or more of the total air amount used for the primary combustion, and the waste is primarily burned, so that combustion is performed under a low oxygen concentration. Since it does not generate high heat, it does not happen that a low melting point substance such as aluminum melts to generate a clinker.

Further, since the secondary air is supplied to the freeboard portion through which the combustion gas generated in the primary combustion passes, the unburned gas is completely burned.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. It should be noted that components similar to or having the same function as in the conventional example are denoted by the same reference numerals, and the description thereof will be omitted unless necessary.

FIG. 1 is a flow chart of the present embodiment. In the figure, 4 sucks the exhaust gas after the exhaust gas treatment from the downstream of the exhaust gas treatment apparatus 10 and sends it to the wind box 12 at the bottom of the fluidized bed incinerator 2. An exhaust gas circulation blower for sending in together with the primary air sent from the fluidized air blower 3, 6 is an ash cooling device for taking out and cooling the incombustibles deposited on the bottom of the fluidized bed incinerator 2 to the outside of the furnace, and 7 is ash cooling A valuable material recovery device for recovering valuable material such as aluminum from the incombustible material cooled by the device 6, 12 is a primary air and exhaust gas circulation from the fluidized air blower 3 evenly from the bottom of the fluidized bed incinerator 2. Blower 4
It is a wind box for sending the exhaust gas from the car as a mixed gas.

Other components are the same as the conventional example,
The overall configuration is greatly different in that the secondary combustion furnace 13 interposed between the fluidized bed incinerator 2 and the heat recovery device 8 in the conventional example is abolished in this embodiment. Therefore, the secondary air sent from the secondary air fan 5 is sent to the freeboard section of the fluidized bed incinerator 2. That is, the secondary combustion of unburned gas is performed in the fluidized bed incinerator 2.

Next, the operation of the above configuration will be described. Waste to be incinerated is supplied by the feeder 1 to the fluidized bed incinerator 2
Is supplied to. The fluidized air (primary air) is normal air from the fluidized air blower 3 and the exhaust gas after exhaust gas treatment from the exhaust gas circulation blower 4 at a ratio of 20% or more of the fluidized air to the wind box at the bottom of the furnace. Send to 12, mix and inject. On the other hand, the secondary air is supplied from the secondary air fan 5 to the nozzle provided on the upper part of the freeboard, and the oxidative combustion is aimed at here.

The incombustible material deposited on the bottom of the fluidized bed incinerator 2 is cooled by the ash cooling device 6 and then the valuable material recovery device 7 recovers valuable material such as aluminum.

As described above, according to this embodiment, since the exhaust gas is mixed with the fluidized air by the exhaust gas circulation blower 4,
For example, if the air in the fluidized air, and thus the oxygen, is too rich to burn the waste at a high temperature, and the heat of formation is likely to melt a relatively low melting point contaminant such as aluminum to form a clinker. It has the advantages of increasing the amount of admixture with oxygen to suppress oxygen in the fluidized air and lowering the combustion temperature to prevent the generation of clinker.

Therefore, the clinker does not cause the inside of the furnace to become inoperable, which makes continuous operation difficult for a long period of time, and troubles such as solidification and adhesion of the molten substance in the subsequent heat recovery device 8 do not occur. It has the advantage of disappearing.

Further, the ash cooling device 6 and the valuable resource recovery device 7
Since a valuable material such as aluminum is collected by installing the above, there is an advantage that the factor causing the clinker at the bottom of the furnace is always eliminated.

Further, since the secondary air is sent by the secondary air fan 5 to the freeboard section of the fluidized bed incinerator 2 for complete combustion, a secondary combustion furnace is not required as in the conventional case, and the cost is correspondingly low. There is an advantage that the device can be obtained and the space of the facility can be reduced.

[0021]

Since the present invention is constructed as described above, it has the following effects.

That is, the combustion exhaust gas is mixed into the primary air.
Because of the exhaust gas amount of circulation, O of the supply air ₂You can adjust the concentration
As a result, the burning rate can be controlled, and
At the highest, for example, 550 to 600 ° C below the melting point of aluminum
It is possible to incinerate it and collect it without melting aluminum.
It

Further, since the secondary air is supplied to the freeboard portion of the incinerator to completely burn the unburned components, the secondary combustion furnace becomes unnecessary.

Further, since the valuable material recovery device is provided, the low melting point material such as aluminum does not remain in the furnace,
The incidence of clinker is correspondingly reduced.

[Brief description of drawings]

FIG. 1 is a flow diagram of a waste fluidized bed incinerator according to an apparatus and method of an embodiment of the present invention.

FIG. 2 is a flow diagram showing a conventional waste incinerator.

[Explanation of symbols]

1 Supply feeder 2 fluidized bed incinerator 3 fluidized air blower 4 Exhaust gas circulation blower 5 Secondary air fan 6 Ash cooling system 7 Valuable material recovery device 8 heat recovery device 9 Exhaust gas fan 10 Exhaust gas treatment equipment 11 chimney 12 wind boxes

Claims (2)

[Claims] 1. In an incinerator for waste including harmful substances such as municipal waste and industrial waste, an exhaust gas supply means for mixing combustion exhaust gas into primary combustion air and a secondary to a freeboard part of an incinerator. A waste incinerator comprising an air supply means and a recovery device for recovering valuable materials such as aluminum contained in the waste. 2. In order to reduce the oxygen concentration and to perform primary combustion of waste in a reducing atmosphere, 20% or more of combustion exhaust gas is mixed in with respect to the total amount of air, and the waste is used as primary air to burn the waste. A waste incineration method characterized by supplying secondary air to the freeboard section to completely burn unburned components.