JP3776584B2 - Combustion furnace and combustion promotion method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion furnace using waste such as waste, coal, oil, etc. as a fuel and a combustion promotion method of the combustion furnace, and particularly in a fluidized bed, a stoker, and other upper combustion chambers located above other hearths. The present invention relates to a combustion furnace provided with a secondary air supply unit and a combustion promoting method for a combustion furnace that promotes combustion by supplying secondary air to the upper combustion chamber.
[0002]
[Prior art]
Combustion furnaces that use waste such as waste, coal, oil, etc. as fuel, especially municipal wastes, are generally stoker furnaces and fluidized furnaces, both of which are located above the hearth made up of stokers and fluidized beds. An upper combustion chamber is provided, and unburned components that could not be combusted by primary combustion on the hearth are combusted by secondary air supplied from the upper combustion chamber inlet.
[0003]
FIG. 2 shows a schematic configuration of a fluidized bed combustion furnace 1 having such an upper combustion chamber, 2 is a chute (hopper) into which raw garbage is charged, and 5 is a dispersion plate in which a large number of air holes are formed. Further, primary air (fluidized air) 4 is supplied, and in the fluidized bed 6 provided at the upper part of the dispersion plate 5, it is vigorously mixed with the combustibles such as dust and coal charged with high-temperature fluidized sand and gasified in dry distillation in a short time. And burn.
[0004]
An upper combustion chamber 7 extending upward is provided above the fluidized bed 6, and a furnace wall on the charging side (front side) of the chute 2 of the combustion chamber 7 and a rear furnace wall facing it. Each of them is provided with OFA nozzles (overfire air nozzles, hereinafter referred to as secondary air supply nozzles) 3 and 3, and unburned gas and light dust are supplied from the secondary air supply nozzle 3 in the upper combustion chamber 7. After burning by B, the exhaust gas 8 is guided to the outside such as a boiler.
[0005]
[Problems to be solved by the invention]
The conventional technique using such a secondary air supply nozzle (FIG. 2) is a method aiming at complete combustion by devising parameters of the position, angle, blowing flow velocity, and blowing nozzle diameter of the secondary air B blown into the upper combustion chamber 7. However, it is not easy to find the optimum values of these parameters, and there is a problem that combustion improvement cannot be expected if the parameters are not well set.
[0006]
For this reason, the prior art shown in FIG. 3 in which the furnace structure is devised has been proposed.
In FIG. 3, a pair of protrusions 9 and 9 are provided on the inner wall of the furnace wall facing the upper combustion chamber 7, and the acceleration effect by narrowing the flow path of the combustion gas and the mixing promotion effect by the generation of vortices after passing the protrusion 9 It is intended to improve combustion.
This method has the problem that the remodeling work becomes large in the existing furnace and the cost increases in the new furnace.
[0007]
At present, a technique combining both the furnace structure and the secondary air supply method, which combines FIG. 1 and FIG. 2, is disclosed, but the drawbacks thereof are not different from those described above.
[0008]
An object of the present invention is to attach a simple combustion accelerator to the upper combustion chamber, thereby providing a combustion gas increasing / decelerating effect and enabling secondary air to be uniformly diffused (exuded) and combustion promotion thereof. It aims to provide a method.
[0009]
[Means for Solving the Problems]
The present invention has a porous structure having a vent hole in the axial direction so that air can smoothly enter the center of the shaft, such as ceramic, and the air that has passed through the vent hole is diffused to the outside from the outer peripheral surface through hole The tube, preferably the porous tube, is configured such that the air hole density is adjusted in the axial direction so that air can smoothly enter to the center of the shaft, and the shaft end side is sparse and the shaft center side is dense. The gist of the present invention is that a porous tube combustion accelerator is installed in an upper combustion chamber (combustion section, furnace) of a combustion furnace, and secondary air is supplied therefrom.
That is, in the invention according to claim 1, in the combustion furnace in which the secondary air supply unit is provided in the upper combustion chamber located above the hearth, such as a fluidized bed, a stoker,
A porous structure having a vent hole in the axial direction so that air can smoothly enter the center of the shaft in the upper combustion chamber, and the air that has passed through the vent hole is diffused to the outside from the outer circumferential surface through hole established a combustion promotion body ing from the tube bundle, and configured to supply the secondary air through the combustion promotion body,
Further, the porous tube is characterized in that the air hole density is adjusted in the axial direction so that air can smoothly enter the center of the shaft, and the shaft end side is sparse and the shaft center side is dense. .
[0010]
In this case, as described in claim 2, the air hole density is adjusted in the axial direction so that air can smoothly enter to the center of the shaft, and the porosity is set so that the shaft end side is sparse and the shaft center side is dense It is preferable that the combustion accelerator is configured by arranging a plurality of porous tube groups in which a large number of material tubes are arranged in multiple rows in the furnace width direction and in multiple stages in the combustion gas flow direction.
[0011]
Invention of Claim 3 is invention regarding the combustion promotion method of the combustion furnace which accelerates | stimulates combustion effectively using this apparatus, and air can penetrate | invade smoothly to the axial center installed in the said upper combustion chamber part a vent density was adjusted in the axial direction, sparsely shaft end, the shaft center side is made of a porous tube bundle formed by arranging a large number of porous tubes is set to be a dense porous tube type combustion promotion body The combustion gas flow rate is increased and decreased alternately, and combustion is promoted by supplying secondary air to the turbulent energy increase region through the porous tubular combustion accelerator. To do.
[0012]
Invention of Claim 4 is a combustion furnace which provides an upper combustion chamber above a fluidized bed, a stoker, and other hearths,
In the upper combustion chamber, the porous tube is set so that the air hole density is adjusted in the axial direction so that air can smoothly enter the shaft center , and the shaft end side is sparse and the shaft center side is dense. by placing the porous tube type combustion promotion body a porous tube formed by arranging many who are, an increase in the combustion gas flow rate through the said multiple tube bundle, alternately to generate reduced, turbulent energy increases The secondary air is supplied to the turbulent energy increasing region via the porous tube combustion accelerator.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.
[0014]
FIG. 1 shows a schematic configuration of a fluidized bed combustion furnace having an upper combustion chamber according to an embodiment of the present invention, and FIG. 4 shows a schematic configuration of a porous tubular combustion accelerator according to the main part of the embodiment of FIG. They are a perspective view (b) which shows this, and a longitudinal cross-sectional view (a) which shows the effect.
In the embodiment of FIG. 1, a tube group 11 in which a plurality of porous tubes 11 a having continuous through holes such as ceramic as shown in FIG. 4 are arranged in parallel is shown in FIGS. 4B and 5. The support plates 12 attached to both ends thereof are integrally fixed, and the tube contact surface of the support plate 12 has an opening 12a. Further, the secondary air B is configured to be able to enter.
The porous tube 11a is set so that the air hole 11b density is adjusted in the axial direction so that air can smoothly enter the shaft center, and the shaft end side is sparse and the shaft center side is dense.
In the fluidized bed combustion furnace 1 shown in FIG. 1, the porous tube type combustion accelerator 10 composed of a large number of tube groups 11 is installed in the upper combustion chamber 7, and air ( Secondary air) B is supplied, and the air that has passed through the porous tube 11a is diffused to the outside through the outer peripheral surface through-holes 11b.
[0015]
The operation of this embodiment will be described with reference to the operation diagram of FIG.
(1) When the combustion gas A passes through the porous tubular combustion accelerator 10, the flow path is reduced by the arrangement of the tube group 11, the gas flow rate is increased, and the tube group 11 is not present. The expansion of the flow path and the decrease of the gas flow rate thereby occur alternately, the turbulent energy of the gas flow increases, and the mixing with the secondary air B is promoted.
Therefore, the chance that oxygen in the combustion gas A meets the unburned components is greatly increased, and combustion is promoted.
[0016]
(2) In this state, air (secondary air) B is supplied to the porous tube group 11 constituting the porous tube combustion promoting body 10, and the secondary air B is supplied to the furnace from the outer peripheral surface through-hole 11b of the porous tube 11a. By allowing the air to diffuse (bleed out) inside, the secondary air (oxygen) B can be effectively supplied to the portion where the turbulent energy is increasing, so that combustion is promoted.
[0017]
(3) Since the tube group 11 disposed in the area is heated by the combustion in the upper combustion chamber 7, and the porous tubular combustion accelerator 10 itself plays a role like a mirror of radiant energy, Since a part of the radiant heat energy is reflected through the tube group 11 in the furnace, non-uniform temperature in the furnace can be reduced, stable combustion can be ensured, and decomposition of harmful substances can be promoted.
[0018]
Although the present embodiment describes a fluidized bed incinerator, it can be easily understood that the present invention can also be applied to a stoker furnace.
[0019]
【The invention's effect】
As described above, according to the first to fifth aspects of the present invention, the increase and decrease of the gas flow rate alternately occur in the porous tube type combustion accelerator arrangement region, the turbulent energy of the gas flow increases, and the secondary air The mixing is promoted, so that the chance that the oxygen in the combustion gas and the unburned components meet is greatly increased, and the combustion is promoted.
The porous tube combustion accelerator itself plays a role like a mirror, and a part of the radiant heat energy is reflected, so the temperature in the furnace is less uneven, stable combustion can be ensured, and toxic substance decomposition is promoted. be able to.
[0020]
To front Symbol pipe group 11 especially is formed of a porous tube, by secondary air is air diffuser (oozing) to the porous tube outer peripheral surface from the furnace, and turbulent energy increases Since air (oxygen) can be effectively supplied to the existing portion, combustion is promoted.
[Brief description of the drawings]
FIG. 1 shows a schematic configuration of a fluidized bed combustion furnace including an upper combustion chamber according to an embodiment of the present invention.
FIG. 2 shows a schematic configuration of a fluidized bed combustion furnace having a secondary air supply nozzle in an upper combustion chamber according to the prior art.
FIG. 3 shows a schematic configuration of a fluidized bed combustion furnace in which a throttle portion is provided in an upper combustion chamber according to a conventional technique.
4 is a perspective view (b) showing a schematic configuration of a porous tubular combustion accelerator according to the main part of the embodiment of FIG. 1, and a longitudinal sectional view (a) showing the effect thereof.
5 is a view showing a state where the porous tubular combustion accelerator of FIG. 5 is installed in a furnace.
[Explanation of symbols]
1 Fluidized bed combustion furnace 2 Chute (hopper)
3 Secondary air supply nozzle 4 Primary air (fluidized air)
5 Dispersion plate 6 Fluidized bed 7 Upper combustion chamber 8 Exhaust gas 9 Protrusion 10 Combustion accelerator

Claims (4)

In a combustion furnace in which a secondary air supply unit is provided in an upper combustion chamber located above a fluidized bed, stoker, or other hearth,
A porous structure having a vent hole in the axial direction so that air can smoothly enter the center of the shaft in the upper combustion chamber, and the air that has passed through the vent hole is diffused to the outside from the outer circumferential surface through hole A combustion accelerator composed of a tube group is installed, and the secondary air is supplied through the combustion accelerator;
Further, the porous tube is characterized in that the air hole density is adjusted in the axial direction so that air can smoothly enter the center of the shaft, and the shaft end side is sparse and the shaft center side is dense. Combustion furnace. A porous tube in which a large number of porous tubes are arranged so that the air hole density is adjusted in the axial direction so that air can smoothly enter the shaft center , and the shaft end side is sparse and the shaft center side is dense. 2. The combustion furnace according to claim 1, wherein the combustion accelerator is configured by arranging groups in multiple rows in the furnace width direction and in multiple stages in the combustion gas flow direction. In a combustion promoting method for a combustion furnace that promotes combustion by supplying secondary air to a fluidized bed, a stoker, or other upper combustion chamber located above the hearth,
A porous tube which is adjusted so that the air hole density is adjusted in the axial direction so that air can smoothly enter the center of the shaft installed in the upper combustion chamber , and the shaft end side is sparse and the shaft center side is dense By using a porous tube type combustion accelerator composed of a plurality of porous tube groups, the combustion gas flow rate is alternately increased and decreased, and the porous tube type combustion accelerator is disposed in the turbulent energy increase region. A combustion promoting method for a combustion furnace, characterized in that combustion is promoted by supplying secondary air through the combustion air. In a combustion furnace in which an upper combustion chamber is provided above a fluidized bed, stoker, or other hearth,
In the upper combustion chamber, the porous tube is set so that the air hole density is adjusted in the axial direction so that air can smoothly enter the shaft center, and the shaft end side is sparse and the shaft center side is dense. by placing the porous tube type combustion promotion body a porous tube formed by arranging many who are, an increase in the combustion gas flow rate through the said multiple tube bundle, alternately to generate reduced, turbulent energy increases A combustion furnace characterized in that secondary air is supplied to the turbulent energy increase region via the porous tube combustion accelerator.

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