JPH11287419A - Incinerator and operating method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an incinerator with a simple structure and an operating method therefor capable of obtaining uniform and highly efficient combustion property without preliminary treatment of waste such as municipal waste or the like and efficiently recovering heat generated by burning the waste in a combustion chamber. SOLUTION: The incinerator 1 is provided with an air chamber 2 and an incombustibles-discharging outlet 3' in a lower part and a combustion chamber 4 provided via a dispersing plate 5 above the air chamber 2, wherein a fluidized bed 6 is formed above the dispersing plate 5. In this case, blowing gas is blown from a blowing hole 8 for floating and suspending fluid media in the vicinity of a fluid medium lower part concentrated bed interface 7 in the combustion chamber 4 so that the fluid media are allowed to rise from the interface 7, that fluid medium concentration above the fluid medium lower part concentrated bed interface 7 decreases slowly, and that a concentration gradient in a combustion chamber outlet 11 allows the fluid media not to disperse by accompanying exhaust gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A circulating fluidized bed incinerator is disclosed in JP-A-4-350409 as a fluidized bed incinerator for incinerating waste such as municipal waste. This circulating fluidized bed incinerator has a main incinerator that burns incinerators in a high-speed fluidized bed, a cyclone that collects fluidized medium particles discharged from the main incinerator, and an incinerator input section. A pyrolysis furnace for thermally decomposing the incinerated material by the heat of the fluidized medium particles, a pneumatic control valve for controlling the amount of the fluidized media particles and the incinerated material supplied to the main cooling furnace, and a heat generated from the pyrolysis furnace It is composed of a pyrolysis gas supply channel for supplying the pyrolysis gas to the main incinerator, and a pyrolysis gas cooling section provided in the pyrolysis gas supply channel. This circulating fluidized bed incinerator has an advantage that uniform and highly efficient combustion characteristics can be obtained.

[0003] Further, in the specification of Japanese Patent No. 2664645, when heat is recovered in a combustion chamber in a bubble fluidized bed incinerator, a temperature gradient is generated in a heat recovery section, the temperature is reduced, and harmful substances such as dioxin are reduced. In order to generate the heat, the heat is recovered in the fluidized bed so that the temperature becomes uniform, and a waste heat boiler is installed afterward, and the temperature of the combustion chamber in the furnace is uniformly controlled by water injection.

[0004]

However, the above-mentioned circulating fluidized bed incinerator requires a device for recovering the fluidized medium with a cyclone and re-supplying it to the main combustion section in order to circulate the fluidized medium. However, there is a disadvantage that the apparatus becomes large. In addition, if waste is supplied without prior treatment, it becomes a disturbance to combustion, combustion becomes unstable, and the amount of evaporation of the boiler fluctuates. There are problems such as an increase in size.

[0005] In the bubble fluidized bed incinerator,
Water is injected for controlling the temperature of the combustion chamber, and heat is lost due to the latent heat of evaporation of the injected water, so that the efficiency of heat recovery in the subsequent boiler is reduced.

According to the present invention, uniform and highly efficient combustion characteristics can be obtained without pre-processing waste such as municipal garbage, the generation of harmful substances such as dioxins can be suppressed, and the combustion efficiency can be stably increased in the combustion chamber. The present invention provides an incinerator having a simple structure capable of recovering heat by using the incinerator and a method of operating the incinerator.

[0007]

According to the present invention, an air chamber and a noncombustible material outlet are provided at a lower portion, and a combustion chamber is provided at an upper portion thereof through a dispersion plate having a plurality of holes, and a fluidized bed is formed on the dispersion plate. In the incinerator that is formed, in the vicinity of the fluidized medium lower dense layer interface of the combustion chamber, the fluidized medium is raised from the interface and suspended in a high concentration above the fluidized medium lower dense layer interface, and at the combustion chamber outlet. Is characterized in that a gas inlet for floating / suspending a fluid medium for blowing a gas into a combustion chamber for controlling the fluid medium so as not to be scattered along with the exhaust gas is provided.

In the method for operating an incinerator according to the present invention, the air chamber and the incombustible substance discharge port are provided at the lower part, and the combustion chamber is provided at the upper part via a dispersion plate having a plurality of holes. By flowing gas into the combustion chamber from the vicinity of the lower fluidized layer interface level at the bottom of the incinerator where the layer is formed, the fluidized medium is further raised from the fluidized medium lower dense layer interface,
It is characterized by being suspended and suspended at a high concentration and controlled so that the fluid medium is not scattered at the outlet of the combustion chamber along with the exhaust gas.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the incinerator of the present invention, at least a part of the combustion air or a part of the combustion air may be used as the gas for suspending / suspending the fluid medium. Turbidity gas inlets may be provided in multiple stages. In order to recover heat, a water-cooled furnace wall can be formed in the combustion chamber, or an evaporating tube group can be arranged in the combustion chamber.
At least a part of these may be provided with a refractory lining. A combustion air inlet for supplying combustion air may be provided in the upper part of the combustion chamber. A resistor may be provided to keep the concentration of the fluid medium suspended and suspended in the combustion chamber at a high level. It can also be formed by a group of evaporative tubes lined with material.

In the operation method of the incinerator according to the present invention, combustion air may be supplied to the upper part of the combustion chamber, or a part of the combustion exhaust gas is circulated from the gas inlet for suspending / suspending the fluid medium. Gas may be blown. In addition, floating medium
By adjusting the gas flow rate from the gas inlet for suspension, the flow state of the fluidized medium can be controlled, and by controlling the flow state of the fluidized medium, the temperature of each part in the furnace can be adjusted. Can be.

FIG. 1 is an overall view of an incinerator showing one embodiment of the present invention, and a graph showing an example of a flowing medium concentration in a combustion chamber.

The incinerator 1 is provided with an air chamber 2 and a noncombustible material discharge port 3 at a lower portion, and a combustion chamber 4 at an upper portion thereof through a dispersion plate 5 having a plurality of holes. The air chamber 2 is placed on the dispersion plate 5.
The fluidized bed 6 is formed by blowing out the air introduced from the dispersing plate 5. At the fluid medium lower dense layer interface level 7 on the furnace wall, air is blown into the combustion chamber 4 to inject the air into the combustion chamber 4 in order to further raise and float and suspend the fluid medium from the fluid medium lower dense layer interface. A plurality of inlets 8 are provided at intervals around the furnace. The furnace wall is provided with a dust supply port 9 and a combustion air blowing port 10.

By adjusting the amount of gas blown from the gas inlet 8 for floating and suspending the fluid medium, the concentration of the fluid medium and the flow state at each level of the combustion chamber 4 are controlled.

As shown in the graph on the left side of FIG. 1, in the combustion chamber 4, the fluid medium is suspended at a high concentration so that the fluid medium is not scattered along with the exhaust gas at the combustion chamber outlet 11. . The exhaust gas discharged from the combustion chamber outlet 11 is recovered by the boiler 12 for heat, and the exhaust gas temperature controller 13
After being cooled by the dust collector 14 and collected by the dust collector 14, the dust is discharged from the chimney 15.

With the above structure, air is blown as a gas from the gas blowing port 8 for floating / suspending the fluid medium, and the fluid medium is suspended in the combustion chamber 4 at a high concentration. Since the stirring and mixing of the unburned particles and the combustion air are promoted, complete combustion is achieved, and the thermal conductivity is improved, so that the inside of the combustion chamber 4 is kept at a uniform temperature. As a result, problems such as adhesion of the clinker generated by local high temperature during combustion to the furnace inner wall and generation of NOx do not occur.
In addition, dioxin and the like are not generated by achieving complete combustion, and emission of harmful substances in exhaust gas can be reduced.

In this embodiment, a heat recovery unit 16 such as a group of evaporating tubes is disposed in the combustion chamber 4, and heat recovery water is preheated by a boiler 12 attached to the incinerator 1 and heat exchanged by the heat recovery unit 16. Then, steam is generated to recover heat. When the heat recovery unit 16 is inserted into the combustion chamber 4, the stirring effect is increased and complete combustion can be achieved.

In the combustion chamber 4, since the fluid medium is suspended and dispersed at a high concentration, the temperature inside the combustion chamber can be kept constant. Therefore, even when the heat recovery unit 16 is provided in the combustion chamber 4, heat can be recovered with high efficiency without generating a temperature gradient.

Air is blown from the gas inlet 8 for floating / suspension of the fluid medium to adjust the fluid state and the particle concentration of the fluid medium, so that the heat transfer state in the heat recovery unit and the waste material By changing the amount of heat generated by combustion, the amount of heat recovery can be controlled, thereby controlling the furnace temperature.

In the heat recovery section 16, the heat transfer state can be changed by adjusting the amount of combustion air from the combustion air inlet 10, thereby controlling the heat recovery amount. Therefore, heat recovery can be performed efficiently while maintaining the combustion chamber temperature at an optimum level and suppressing the generation of harmful substances.

In the conventional bubble fluidized bed incinerator, water is injected for controlling the temperature of the combustion chamber. According to the present invention, the heat loss caused by the injection can be recovered. In addition, since complete combustion has been achieved by stirring and mixing due to the flowing of the fluid medium in the combustion chamber, compared to the conventional bubble fluidized bed incinerator, even when the amount of combustion air is reduced, it is sufficient. Oxygen and unburned gas come into contact, and complete combustion can be achieved. For this reason, when the amount of refuse (heat) supplied to the incinerator and the temperature of the combustion exhaust gas are kept constant, the amount of exhaust gas decreases, so that the amount of heat that can be absorbed to maintain the temperature constant increases. In addition, by circulating a part of the combustion exhaust gas and supplying it into the furnace, the heat discharged from the system by the combustion exhaust gas can be reduced, and the heat recovery efficiency of the system is improved. Can be done. At the same time, by changing the combustion state in the combustion chamber, the temperature inside the furnace can be changed, and the heat recovery amount can also be changed.

FIG. 2 is an overall view of an incinerator showing another embodiment of the present invention, and a graph showing an example of the concentration of a flowing medium in a combustion chamber. The same members as those of the incinerator shown in FIG.
The description is omitted.

In this embodiment, the gas inlets 8a, 8b, 8c for floating / suspending the fluid medium are arranged in a plurality of stages, and the gas inlets 8a, 8b, 8c8 for the fluid medium floating / suspending are arranged. By adjusting the gas blowing amount, the fluid medium can be suspended in the combustion chamber 4 at a high concentration.

FIG. 3 is an overall view of an incinerator showing a further embodiment of the present invention and a graph showing an example of the concentration of a flowing medium in a combustion chamber. The same members as those of the incinerator shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The furnace wall of the combustion chamber 4 is constituted by a water-cooling wall 17, and the heat recovery water is preheated by a boiler 12 attached to the incinerator 1 and flows through the water-cooling wall 17 to generate steam to recover heat. .

FIG. 4 is a perspective view showing a resistor provided in a combustion chamber according to another embodiment of the present invention. The same members as those of the incinerator shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. A resistor 18 is provided inside the combustion chamber 4 in order to maintain the floating fluid medium at a high concentration. In the present embodiment, the resistor 18 is a cylinder in which a cylinder is arranged so as to intersect on an arbitrary cross section in the combustion chamber 4. However, the flat plate is inserted so as to block a part of the cross section. Another form such as installation on a fin in the vertical direction may be used. Further, the resistor 18 may be a group of evaporating tubes for heat recovery, or a group of evaporating tubes having at least a part of which is provided with a refractory lining. With this resistor, the fluid medium in the combustion chamber 4 can be maintained at a high concentration, and therefore, the mixing and stirring effect of the fluid medium is further improved as described above.

[0026]

In the incinerator according to the present invention, refuse is introduced into the dense phase of the lower fluidized medium, and at least a part of the refuse is burned, and a part of the refuse becomes combustible gas and unburned particles. Due to the turbid flowing medium, the combustible gas and unburned particles are vigorously stirred and mixed with the air, and are completely burned.

Unburned gas generated when a large amount of refuse is supplied to the lower concentrated phase at a time and rapidly combusted can be completely burned by mixing and stirring with the combustion air of the floating and suspended fluid medium. .

By controlling the flow state in the combustion chamber and the rich phase of the lower fluid medium using a part of the combustion air or a part of the combustion exhaust gas, the flow state (heat conductivity) in each part, the supply amount of oxygen The effect of stirring and mixing can be changed, and the temperature in each part in the furnace can be controlled uniformly at the optimum temperature.

Further, by providing a resistor in the combustion chamber, the floating fluid medium can be maintained at a high concentration,
The effect of mixing and stirring the combustion air with the unburned gas and the unburned particles can be improved.

According to the present invention, no pretreatment is required for incineration, so that the auxiliary equipment is simple.
Heat recovery from the combustion chamber, which was difficult in a bubble fluidized bed incinerator, becomes possible, and the heat recovery efficiency increases. In addition, uniform and highly efficient combustion characteristics, which are advantages of the external circulating fluidized bed, can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall view of an incinerator showing one embodiment of the present invention, and a graph showing a flowing medium concentration in a combustion chamber.

FIG. 2 is an overall view of an incinerator showing another embodiment of the present invention, and a graph showing a flowing medium concentration in a combustion chamber.

FIG. 3 is an overall view of an incinerator and a graph showing the concentration of a flowing medium in a combustion chamber, showing still another embodiment of the present invention.

FIG. 4 is a perspective view showing a resistor provided in a combustion chamber according to another embodiment of the present invention.

[Explanation of symbols]

1: incinerator 2: air chamber 3: incombustible discharge
4: Combustion chamber 5: Dispersion plate 6: Fluidized bed 7: Lower layer interface level of fluidized medium lower part 8: Gas inlet for suspension / suspension of fluidized medium 9: Garbage supply port 10: Air inlet for combustion 11: Combustion chamber Exit 12: Boiler 1
3: Exhaust gas temperature controller 14: Dust collector 15: Chimney 16: Heat recovery unit 17: Water cooling wall 18: Resistor

Claims (14)

[Claims] An incinerator in which an air chamber and a noncombustible material outlet are provided at a lower portion, and a combustion chamber is provided at an upper portion thereof through a dispersion plate having a plurality of holes, and a fluidized bed is formed on the dispersion plate.
In the vicinity of the interface of the lower layer of the fluidized medium in the combustion chamber, the fluidized medium rises from the interface and is suspended in a high concentration above the interface of the layer of the fluidized medium lower dense layer, and flows along with the exhaust gas at the outlet of the combustion chamber. An incinerator comprising a gas inlet for floating / suspending a fluid medium for injecting a gas into a combustion chamber for controlling the medium so that the medium is not scattered. 2. The incinerator according to claim 1, wherein at least a part of the combustion air is used as the gas to be suspended and suspended. 3. The incinerator according to claim 1, wherein at least a part of the combustion air and a part of the combustion exhaust gas are used as the gas to be suspended and suspended. 4. The incinerator according to claim 1, wherein the gas inlet for floating / suspension of the fluid medium is provided in multiple stages, and the flow rate is adjusted to control the concentration of the fluid medium. 5. The incinerator according to claim 1, wherein a heat exchange part is formed in the combustion chamber. 6. The incinerator according to claim 5, wherein the heat exchanging part is a water-cooled furnace wall or a water-cooled furnace wall having at least a part provided with a refractory lining. 7. The incinerator according to claim 5, wherein the heat exchange section is a group of evaporating tubes arranged in the combustion chamber or a group of evaporating tubes having at least a part of which is provided with a refractory lining. 8. A combustion air inlet for supplying combustion air is provided at an upper portion of the combustion chamber.
The incinerator according to 3, 4, 5, 6, or 7. 9. The apparatus according to claim 1, further comprising a resistor for maintaining a high concentration of the fluidized medium suspended and suspended in the combustion chamber of the incinerator. 6. The incinerator according to 6, 7, or 8. 10. An evaporating tube group for recovering heat, wherein the resistor comprises:
10. The incinerator according to claim 9, wherein the incinerator is constituted of a group of evaporating tubes at least partially refractory-lined. 11. An incinerator bottom in which an air chamber and a noncombustible material outlet are provided at a lower portion, and a combustion chamber is provided at an upper portion thereof through a dispersion plate having a plurality of holes, and a fluidized bed is formed on the dispersion plate. By flowing gas into the combustion chamber from near the interface of the dense layer of the lower part of the fluid medium, the fluid medium is further raised from the dense layer interface of the lower part of the fluid medium, and is suspended and suspended at a high concentration. A method for operating an incinerator, characterized in that control is performed so that the fluid medium is not scattered along with it. 12. The method for operating an incinerator according to claim 11, wherein air for combustion is supplied to an upper portion of the combustion chamber. 13. The fluid medium is further raised from the fluid medium lower dense phase interface, and the fluid medium is suspended at a high concentration above the fluid medium lower dense phase interface. The method for operating an incinerator according to claim 11, wherein the gas to be passed is a part of the combustion exhaust gas. 14. A method of controlling the temperature of each part in the furnace by raising the temperature of the fluid medium from the lower concentrated phase to the upper part and adjusting the flow state of the fluid medium suspended and suspended at a high concentration. The method for operating an incinerator according to claim 11, 12, or 13.