JP2649626B2 - Fluidized bed combustion device with integrated exhaust gas passage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed combustion apparatus and, more particularly, to a compact apparatus for burning solid substances such as industrial waste, municipal waste and coal, and to minimize the generation of unburned gas. The present invention relates to a fluidized bed combustion apparatus that integrates an exhaust gas passage that can be suppressed to a minimum.

[0002]

2. Description of the Related Art Conventionally, various techniques have been proposed for suppressing unburned gas in the combustion of waste and the like. FIG. 6 shows a conventional fluidized bed combustion apparatus for incineration of municipal garbage and industrial waste, etc., in which a combustion furnace 1 is surrounded by a furnace wall 2 and a wind box 6 and an air The object to be incinerated is composed of a dispersion plate 5, a fluidized bed section 4, and a combustion chamber 3. For example, the incineration material put into the furnace from the supply port 8b by the screw feeder 8a flows by the fluidized air 7 inside the fluidized bed 4. After burning while burning, unburned gas or combustion gas containing unburned material flows into the combustion chamber 3 adjacent to the upper portion, and the combustion is continued by the secondary air blown from the nozzle 9, and thereafter, passes through the outlet duct 10. After being guided to a waste heat boiler 11 and converting a predetermined amount of heat into steam, the dust passes through a dust collecting facility 13 through a residual heat recovery facility 12 such as an air preheater or a economizer, and then is passed to a chimney 15 by an induction blower 14. Sent and released into the atmosphere That.

In such a facility, the volume of the combustion chamber 3 is increased to maximize the combustion of unburned gas or unburned substances in the combustion gas, so that the residence time of the combustion gas is increased and the oxygen and oxygen are removed. Although the reaction rate is to be improved, the tower height of the combustion furnace 1 tends to be necessarily increased, and the installation position of the waste heat boiler 11 attached to the outlet thereof is also increased. The supporting frame had to be set high, and the construction costs tended to be expensive. At that time, even if an attempt was made to lower the height of the furnace, there was a certain limit in suppressing the generation of unburned gas and unburned substances.

[0004]

In a fluidized bed combustion apparatus, since the combustion gas generated in the fluidized bed contains unburned gas and substances, the combustion gas is mixed with secondary air in a combustion chamber adjacent to the upper part to maintain a certain level. It is necessary to maintain the residence time to complete the combustion, and therefore, the height of the combustion furnace is increased in order to secure a predetermined residence time, and as a result, the waste heat boiler located at the subsequent stage is supported. Either raise the mount or
Alternatively, the combustion exhaust gas had to be guided downward by a duct, and a structurally useless surface was observed. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fluidized bed combustion apparatus which solves the above-mentioned disadvantages, makes the apparatus compact, and integrates an exhaust gas passage capable of minimizing generation of unburned gas. And

[0005]

In order to solve the above-mentioned problems, in the present invention, a combustion gas generated by burning an incinerated material in a fluidized bed portion is introduced into a combustion chamber adjacent to the upper portion, and the combustion gas is removed by the combustion chamber. In a fluidized bed combustion apparatus configured to complete combustion by mixing with the next air and maintaining a certain residence time, a combustion exhaust gas passage is provided integrally with the combustion chamber via a partition wall adjacent to the combustion chamber. The exhaust gas passage and the combustion chamber are connected at an upper end of a partition wall, and the partition wall has a lower portion burning.
With a structure that protrudes in a triangular or trapezoidal shape toward the room side
And at the furnace wall facing the partition wall of the combustion chamber,
Flows obliquely downward from multiple secondary air nozzles
It is provided facing the layer portion, and the partition wall has
Multiple secondary air nozzles at the upper end are inclined toward the upper combustion chamber
It is to be arranged downward .

[0006] In the fluidized bed combustion apparatus, specification <br/> Setsukabe is composed of a water pipe, and can also be coated with a refractory material, also on the partition wall, the furnace facing the partition wall It is also possible to install one or more beams connecting the furnace wall and the partition wall by traversing the combustion chamber from the wall or extending the furnace wall and the partition wall and connecting the side wall of the exhaust gas passage.

[0007]

According to the present invention, the flue gas passage is incorporated in the combustion furnace so as to be integral with the combustion furnace, and the combustion gas in the combustion chamber is rectified by using a partition wall separating the passage from the combustion chamber. By doing so, it becomes possible to lower the position of the outlet of the combustion exhaust gas from the combustion furnace to an appropriate position. Further, an overhanging portion is provided below the partition wall, and a secondary air blowing nozzle is disposed so as to blow out from the front wall of the combustion chamber facing the partition wall toward the fluidized bed portion , and another secondary air is provided. By arranging the nozzle on the upper part of the partition wall so as to blow diagonally downward on the combustion chamber side, the secondary air ejected from the nozzle arranged on the front wall descends along the front wall, and the rising combustion gas After collision and mixing, this time it rises along the overhang under the partition wall, thereby generating a vertical swirling flow in the combustion chamber to promote agitation and mixing of the secondary air and the combustion gas, and The secondary gas blown obliquely downward from the other secondary air nozzle group formed at the upper part of the partition wall to the place where the combustion gas flow path is narrowed and the flow velocity is increased at the overhang part of the partition wall toward the overhang part Air overhang After flowing through the top at high speed,
The tip of the overhang collides with the combustion gas flow blown up from below.

[0008] This causes vigorous stirring and mixing and generates a swirling flow again in the upper combustion chamber, so that combustion is performed while making the most of the volume of the combustion chamber, and furthermore, the flue gas passage over the upper part of the partition wall. When flowing into the combustion gas flow is reversed, utilizing the kinetic energy of the combustion gas flow to further increase the degree of mixing,
After sufficient combustion, the exhaust gas is discharged to the outside through the flue gas passage. Therefore, the degree of complete combustion is high, and the generation of unburned gas and unburned substances is suppressed to a minimum. Also, as a reinforcing member for the partition wall, pass one or more beams from the front wall of the combustion chamber to the partition wall, the inside of which is generally air-cooled and covered with a refractory material or the like along the gas flow direction. In this case, the combustion gas flow is divided by the beam in the width direction with respect to the flow, and after the beam passes through the beam, they collide again, thereby further enhancing the stirring and mixing effect, and the combustion reaction between the unburned gas and oxygen, It is possible to proceed quickly and reliably and to minimize the emission of unburned gas.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings . Reference Example 1 First , an apparatus on which the present invention is based will be described with reference to the drawings. FIG.
6 shows a combustion furnace in which a combustion exhaust gas passage is incorporated in the combustion furnace shown in FIG. 6, and a combustion exhaust gas passage 17 shown in FIG.
, And is separated from the combustion chamber 3 by a partition wall 16. The partition wall 16 is configured to connect to the left and right furnace walls 2 in a direction perpendicular to the flow of the combustion gas and to connect the combustion chamber 3 and the flue gas passage 17 at the upper part of the partition wall 16. doing. The partition wall 16 is usually formed of a hollow member, and its outer surface is covered with a refractory material, and a cooling effect is given by flowing air or the like through the hollow portion 21. As a result, the combustion exhaust gas outlet 18 can be lowered to an appropriate position, so that the installation position of the waste heat boiler is also lowered, which contributes to a reduction in frame weight and the like. Further, when the combustion gas flows from the combustion chamber 3 into the combustion exhaust gas passage 17, the combustion exhaust gas flow is reversed at the upper part of the partition wall 16, so that the kinetic energy of the gas flow itself allows the combustion gas and the secondary air to be sufficiently mixed. Combustion is promoted, and as a result, emission of unburned gas is suppressed.

However, in the case of a structure such as the combustion furnace 1 shown in FIG.
Flows in the vicinity of the partition wall 16, and despite the blowing of the secondary air from the nozzle 9, the combustion exhaust gas passage 17 from the upper part of the partition wall 16 with insufficient mixing with the secondary air. However, in such a case, the configuration as shown in FIG. 2 is effective. That is, a projection 20 having a triangular or trapezoidal shape is provided at a lower portion of the partition wall 16 separating the combustion chamber 3 and the flue gas passage 17 toward the combustion chamber, thereby substantially dividing the combustion chamber into the lower combustion chamber 3a. And the upper combustion chamber 3b. On the other hand, the secondary air nozzle is disposed obliquely downward along the inclination of the lower portion of the front wall of the combustion furnace 1, that is, so as to be ejected toward the fluidized bed portion 4, and the ejected secondary air is provided below the lower combustion chamber. The combustion gas blows up obliquely upward along the slope of the lower surface of the overhang portion 20 while colliding and mixing with the rising combustion gas, thereby contributing to the promotion of combustion. As a result, the fluidized bed flows from the front wall in the lower combustion chamber 3a. , And then swirl to reverse and blow up along the underside of the overhang 20 to achieve more effective mixing of the combustion gas and oxygen, and to communicate with the upper portion along the partition 16. Since short-circuited drift flowing from the mouth to the flue gas passage can be prevented, sufficient combustion can be performed in the upper combustion chamber 3b.

Embodiment 1 FIG. 3 is an explanatory view showing an example of the combustion apparatus of the present invention.
In FIG. 3, the combustion chamber 3 of FIG.
At the bottom of the partition wall 16,
The combustion chamber is realized by providing an overhang 20 having a trapezoidal shape.
Qualitatively divided into lower combustion chamber 3a and upper combustion chamber 3b,
Attach the air nozzle obliquely downward along the inclination of the lower part of the front wall of the combustion furnace 1.
, That is, in such a manner as to be ejected toward the fluidized bed section 4.
And also in the upper combustion chamber 3b. Like the lower combustion chamber, and constructed so that to generate a swirling flow, the effect of 2
In addition to the above, the present embodiment is configured to perform more effective combustion. That is, regarding the introduction of the secondary air, not only the secondary air nozzle 9 provided on the front wall but also the partition wall 16 having a hollow structure and covered with a refractory material, and the hollow portion at the upper end portion is formed in the secondary air duct. 21a and a plurality of secondary air nozzles 22 obliquely downward toward the upper combustion chamber 3b through the refractory material.
And ejects secondary air. The ejected secondary air flows downward along the partition wall 16 and changes its direction to the center along the upper surface of the overhanging portion 20. When the secondary air exits the tip of the overhanging portion 20, it projects from the lower combustion chamber 3a side. 20 After violently colliding with the combustion gas flow that has risen along the lower surface, the two gas flows rise near the front wall while mixing, so there is no short circuit to the combustion exhaust gas passage, and the internal combustion chamber volume is sufficient. Therefore, the emission of unburned gas and unburned substances is minimized.

Embodiment 2 FIG. 4 shows that in the case of a larger combustion furnace, the combustion furnace shown in FIG. 3 is further devised because it is necessary to reinforce the partition wall 16 and further promote stirring and mixing of the combustion gas. In addition, one or a plurality of reinforcing beams 23 are passed from the front furnace wall 2 toward the upper end of the partition wall 16, that is, along the flow direction of the combustion gas. This beam 23
May stop at the partition wall 16 or may extend and traverse the flue gas passage 17 to reach the furnace wall on the rear side. The beam 23 has a hollow structure, and the outer side is covered with a refractory material.
In the upper combustion chamber 3b, the combustion gas flow is divided into two or more in the upper combustion chamber 3b as shown in the cross section a, the flow velocity is increased, and the fuel gas is remixed vigorously after passing through the beam 23. Spreading, swirling, and mixing in a direction perpendicular to the swirling and mixing combustion gas flow promotes a further combustion reaction, and reduces the amount of unburned gas and unburned substance emissions. This greatly contributes to suppression.

That is, if the whole description is given again in FIG. 4, the incineration material or fuel is supplied from the inlet 8b into the furnace. On the other hand, the primary air for combustion is supplied from the lower part of the furnace as flowing air 7, enters the wind box 6, passes through the air dispersion plate 5, fluidizes the fluidized bed portion 4, and burns the incineration material or the fuel. Combustion gas containing volatile matter, unburned gas, and unburned matter exits the fluidized bed portion 4 and enters the lower combustion chamber 3a, but is blown from the secondary air nozzle 9 obliquely downwardly directed to the front wall to blow the front wall. While rising and falling along the lower surface of the overhang portion 20 while violently colliding and mixing with the secondary air flowing down along the inclination of The secondary air that has been blown obliquely downward toward the chamber side and has flowed down along the upper surface of the overhanging portion 20 and violently impacts and mixes at the tip of the overhanging portion 20 at the tip of the overhanging portion 20 and then swirls inside the upper combustion chamber 3b. As it rises while burning, it is further separated and remixed by the beams 23 at the upper part, further increasing the degree of combustion, and minimizing the emission of unburned gas,
It flows into the flue gas passage 17 and is led out. In the above embodiment, the combustion furnace 1 can be constituted by a combination of a steel shell and a refractory material or a combination of a boiler water pipe and a refractory material.

[0014]

As apparent from the above description, the effects of the present invention are as follows. 1) By incorporating the flue gas passage into the combustion furnace, the position of the flue gas outlet can be set arbitrarily, and the mounting position of the waste heat boiler can be lowered to an appropriate position, contributing to a reduction in construction costs. 2) Combustion by using a partition wall that separates the combustion chamber from the flue gas passage, providing a projecting portion below the partition wall, and generating a swirling flow inside the combustion chamber by the secondary air nozzles on the front wall side and the upper part of the partition wall. As a result of effective mixing of the unburned gas and the secondary air inside the room, it is possible to reduce the amount of unburned gas discharged or the amount of secondary air, and to reduce the temperature of the combustion chamber. It has the effect of being able to be maintained at a high temperature, and is also effective in controlling harmful substances that decompose at high temperatures.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an apparatus on which the present invention is based .

FIG. 2 is a schematic sectional view showing another example of the device on which the present invention is based .

FIG. 3 is a schematic sectional explanatory view showing an example of the apparatus of the present invention.

FIG. 4 is a schematic sectional explanatory view showing another example of the device of the present invention.

FIG. 5 is an explanatory sectional view taken along the line aa in FIG. 4;

FIG. 6 is a schematic explanatory view showing a conventional fluidized bed combustion device.

[Explanation of symbols]

1: combustion furnace, 2: furnace wall, 3: combustion chamber, 4: fluidized bed,
5: air dispersion plate, 6: wind box, 7: flowing air, 8a: screw feeder, 8b: incineration material supply port, 9: secondary air nozzle, 10: outlet duct, 16: partition wall, 17: combustion exhaust gas Passage, 18: exhaust gas outlet, 1
9: exhaust gas, 20: overhang, 21: hollow part, 2
2: Secondary air nozzle, 23: Reinforcement beam.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Keiichi Sato 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Works Co., Ltd. (56) References JP-A-61-17810 (JP, A) Akira Tokubo 34-3689 (JP, B1)

Claims (3)

(57) [Claims] 1. Combustion gas generated by burning incinerated material in a fluidized bed is introduced into a combustion chamber adjacent to the upper part, mixed with secondary air in the combustion chamber to maintain a certain residence time to complete combustion. In the fluidized bed combustion apparatus configured to perform the combustion, a flue gas passage is provided integrally with the combustion chamber via a partition wall adjacent to the combustion chamber, and the flue gas passage and the combustion chamber communicate with each other at an upper end of the partition wall. The partition wall has a lower part in a combustion chamber.
Triangular or trapezoidal structure
And the furnace wall facing the partition wall of the combustion chamber has multiple
Number of secondary air nozzles obliquely blow down the fluidized bed
And the partition wall has an upper part.
Multiple secondary air nozzles at the end diagonally below the upper combustion chamber
Fluidized bed combustion device, characterized in that the device is arranged in a direction to the direction . 2. The partition wall has at least one beam that longitudinally traverses a combustion chamber from a furnace wall facing the partition wall and connects the furnace wall and the partition wall or extends the same and also connects a side wall of an exhaust gas passage. The fluidized- bed combustion apparatus according to claim 1, wherein the apparatus is installed. Wherein said partition wall, according to claim 1 or 2 consists of water pipes, and characterized by a Turkey covered with a refractory material
A fluidized bed combustion device as described.