JP4727515B2 - Air nozzle structure of fluidized bed combustion furnace - Google Patents

Description

The present invention relates to an air nozzle structure of the fluidized bed combustion furnace and processed recycled fuel such as cut tires, screen residue, in particular, recycled fuel containing incombustible foreign matter having an elongated portion comprising a stitcher foreign matter The present invention relates to an air nozzle structure of a fluidized bed combustion furnace that can prevent foreign matter from staying and accumulating in the vicinity of the air nozzle when incineration is performed.

Conventionally, a fluidized bed is filled in the bottom of the combustion furnace, air is blown toward the fluidized material to form a fluidized bed, and an object to be treated is put into the high-temperature fluidized bed to contact the fluidized material. 2. Description of the Related Art Fluidized bed combustion furnaces that are made to burn are known. In addition to the foreign matter-containing waste, there are recycle fuels such as cut tires and screen soots as objects to be treated that are suitable for treatment in such a fluidized bed combustion furnace.
In general, in a fluidized bed combustion furnace, a large number of air nozzles for blowing air for bringing the fluidized bed into a fluidized state are attached to the bottom of the furnace. Air is supplied to the air nozzle through a wind box provided below the furnace bottom, and the fluidized material is fluidized by blowing air from the air nozzle toward the combustion chamber.

The configuration of such an air nozzle is described in Patent Document 1 (Japanese Patent Laid-Open No. 9-299784), Patent Document 2 (Japanese Patent Laid-Open No. 2005-226870), and the like.
Patent Document 1 discloses a configuration of an air nozzle having a double tube structure including a nozzle body attached to the furnace bottom by a screw mechanism and a cap portion covering the nozzle body. A differential pressure adjusting plug having an orifice hole is attached to the lower gas chamber side, and the pressure loss of the nozzle is set by the differential pressure adjusting plug.

  Similarly, Patent Document 2 also shows an air nozzle having a double tube structure. As shown in FIGS. 7 and 8, the air nozzle 51 includes an inner cylindrical pipe 52 that penetrates the furnace bottom 57 and an outer cylindrical pipe 55 that is located outside the inner cylindrical pipe 52. The air supplied from above passes through the inner cylindrical pipe 52 and is supplied to the outer cylindrical pipe 55 through a circular or elliptical opening 53 formed in the peripheral surface above the inner cylindrical pipe 52. The air supplied to the outer tube 55 is blown out horizontally toward the combustion chamber through an opening 56 formed in the peripheral surface below the outer tube 55.

  Recycled fuel as described above often contains nonflammable foreign matter, and a foreign substance discharge port is provided at the bottom of the fluidized bed combustion furnace. Normally, this foreign substance discharge port removes foreign matter from the inside of the furnace. . Foreign matter generated from the recycled fuel is gradually discharged from the foreign matter discharge port while diffusing and moving in the fluidized bed, but some foreign matter is pulsating the air blown from the dispersed nozzles and blown from other nozzles. It enters the inside of the nozzle by air or the like. Foreign materials contained in recycled fuel include stitcher-like objects, long objects, or hook-shaped objects (tips), which are easily entangled with the air holes of the air nozzle and stay and accumulate in the furnace. However, it may lead to troubles such as fluidized bed failure, air nozzle blockage, and foreign matter discharge port blockage.

JP-A-9-299784 JP 2005-226870 A

Patent Document 1 discloses a configuration in which a nozzle pressure loss necessary for fluidization is adjusted with a differential pressure adjustment plug. However, according to this configuration, the nozzle structure becomes complicated, and the pressure loss adjustment is performed in accordance with a change in fuel. Therefore, it is necessary to replace the differential pressure adjusting plug, which is troublesome. Further, Ri our coal combustion furnace or the like as an object, is not considered treatment object scan Tetcha foreign matter is mixed, the residence of such foreign matter, the configuration of the storage prevention is not provided.
Patent Document 2 discloses a structure of an air nozzle having a double tube structure in which an opening through which air flows is formed in each of an inner tube and an outer tube, and the structure is simple and the backflow of a fluid material is prevented. However, if the shape of the opening of the outer tube is circular or elliptical, as shown in FIG. 7, the lower end of the opening 56 extends from the bottom of the nozzle to the bottom of the nozzle. Since the height is generated and the pocket 60 is formed inside the nozzle, there is a problem that foreign matter stays and accumulates in the pocket 60. Therefore, it has been difficult to apply to an object to be processed containing foreign matter at a high concentration. Further, as shown in FIG. 8B, when the stitcher 61 sandwiches between adjacent air holes, there is a problem that it cannot be easily removed and takes a lot of labor.
Therefore, in view of the above-mentioned problems of the prior art, the present invention provides an air nozzle structure for a fluidized bed combustion furnace that can prevent nonflammable foreign substances contained in the workpiece from staying and accumulating in the vicinity of the air nozzle. Objective.

Therefore, in order to solve such a problem, the present invention is an air nozzle structure of a fluidized bed combustion furnace intended for treating recycled fuel containing non-combustible foreign matter having an elongated portion made of stitcher-like foreign matter , A large number of air nozzles are arranged at the bottom of the combustion chamber, and the air nozzle has a double pipe structure consisting of an inner cylinder and an outer cylinder, and an ejection hole having a pressure loss adjusting function is formed above the peripheral surface of the inner cylinder. In addition, in the air nozzle structure of a fluidized bed combustion furnace having air holes drilled below the peripheral surface of the outer cylinder,
Air hole of the outer cylinder, and the upper edge with a curvature linear lower edge is to position the and the straight lower edge straight horseshoe shape or a semicircular shape on the upper surface and the same surface of the furnace bottom,
Furthermore the air pores Mashimashi multiple exist in the circumferential direction of the outer cylinder, the pitch spacing of the air pores is 10 to 30 mm,
On the other hand, there are a plurality of ejection holes of the inner cylinder along the circumferential direction, the ejection holes are provided with a plurality of ejection holes in the vertical direction, and the ejection holes adjacent to the upper and lower sides are arranged in a staggered manner. Features.

In the present invention, by the air hole lower edge of the outer cylinder and the linear to match the upper surface of the lower edge and the furnace bottom, it is possible to eliminate pockets of air nozzles, foreign matter is air holes generated in the combustion chamber It is discharged smoothly from the system without tangling. That is, even if foreign matter enters from the air hole, the entered foreign matter does not stay in the pocket of the air nozzle (see FIG. 7, reference numeral 60), and is easily discharged along the air flow. foreign matter stay in the vicinity of the air hole, that prevent the accumulating.
Furthermore, by making the air nozzle into a double tube structure, the nozzle structure can be simplified, the manufacturing cost can be reduced, and the fluidized material can be prevented from falling into the air nozzle. As the shape of the air holes in the present invention, horse hoof-shaped, semicircular, and the like.

The present invention also ejection hole of the inner cylinder along with presence of a plurality of circumferentially,該噴Deana exists several stages multiple vertically.
Thus, the required pressure loss can be ensured by providing a plurality of ejection holes.
Further, ejection hole vertically adjacent in the present invention, it staggered. Thereby, the vertical width of the existence range of the ejection holes is reduced, the distance of the air flow path from the lower end of the ejection holes to the air holes can be increased, and the air rectifying effect becomes remarkable.

Further, the outer cylinder upper edge shape of the air holes of, by a shape having a curvature line shape of the upper edge as horseshoe or semicircular, machining is facilitated can be reduced in manufacturing cost. Moreover, the part where the distance between adjacent air holes is short decreases, and it can suppress that a stitcher-like foreign material becomes entangled and solidified between these air holes. That is, as shown in FIG. 8B, one of the causes of the accumulation of the stitcher-like foreign matter is fixed in a state where the tip of the stitcher 61 enters the adjacent air hole and the stitcher 61 sandwiches the air hole. It may be done. However, when the upper edge has a curved line shape as in the present invention, as shown in FIG. 3A, the pitch interval P of the air holes (the interval between the adjacent end portions of the two adjacent holes) increases upward. growing. Therefore, the site | part which is the short pitch space | interval P2 can be decreased, and possibility that a stitcher will pinch | interpose between air holes and will be fixed can be made small.

Furthermore, there are a plurality of air holes in the circumferential direction of the outer cylinder, and the pitch interval of the air holes is 10 to 30 mm .
As a result, even for an object to be processed that contains stitcher-like foreign matter, it is possible to prevent foreign matter from being fixed by being sandwiched between the air holes as in the above-described reason. It can be prevented. Thus, the pitch spacing of the air holes of the outer cylinder, more and Dearuko 10 to 30 mm, can be sufficient for most stitcher foreign matter which has been used generally much.

As described above, according to the present invention, the pockets in the air nozzle can be eliminated by matching the lower edge of the air hole of the outer cylinder with the upper surface of the furnace bottom, and foreign matter generated in the combustion chamber is retained in the air nozzle. Accumulation can be prevented, and as a result, smooth operation of the fluidized bed combustion furnace is possible, and maintenance is facilitated.
Moreover, the required pressure loss of the air nozzle can be ensured by providing a plurality of ejection holes in the inner cylinder.
Furthermore, by making the upper edge of the air hole of the outer cylinder a curved line, or by making the pitch interval of the air holes of the outer cylinder larger than the average length of the foreign object, the stitcher-like foreign object is fixed by sandwiching the air holes. It suppresses that.

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, but are merely illustrative examples. Not too much.
1A and 1B show a configuration of an air nozzle according to an embodiment of the present invention, where FIG. 1A is a cross-sectional view, FIG. 2B is a side cross-sectional view, and FIG. (A) is a sectional view taken along line aa in FIG. 1 (B), (b) is a sectional view taken along line bb in FIG. 1 (B), and FIG. 3 is an outer cylinder of the air nozzle shown in FIG. (A) is a horseshoe shape, (b) is a semicircular shape, (c) is a view showing a rectangular shape, and FIG. 4 is a side sectional view showing the overall configuration of the fluidized bed combustion furnace. is there.

  An object to be processed in the fluidized bed combustion furnace of the present embodiment is a recycled fuel such as a cut tire or a screen soot, and includes non-combustible foreign matters having a long portion. Examples of the foreign matter include a stitcher-like foreign matter and a wire-like foreign matter. Recycled fuel refers to an object to be treated that can be discarded after it has been commercialized and can be recovered and used as energy, such as heat, by incinerating the waste.

  Initially, with reference to FIG. 4, the whole structure of the fluidized-bed combustion furnace in which the air nozzle of a present Example is installed is demonstrated. The fluidized bed combustion furnace 20 is provided with a furnace main body 21, a recycled fuel inlet 22 provided on a side wall of the furnace main body 21 to input a recycled fuel into the furnace, and a fluidized material provided similarly on the side wall into the furnace. Fluidized material inlet 23, furnace bottom 25 forming the bottom of the furnace body, foreign matter discharge pipe 26 joined to the furnace bottom 25 for extracting non-combustible foreign matter, and wind provided below the furnace bottom 25 A box 27, a carry-out portion 28 connected to the foreign matter discharge pipe 26, and a separator 29 provided on the downstream side of the carry-out portion 28 to separate the fluidized material and the foreign matter. A large number of air nozzles, which will be described later, protrude from the furnace bottom 25. In addition, this embodiment is suitable for the furnace bottom 25 having a horizontal structure, but can also be applied to the furnace bottom 25 having an inclined structure.

In such a fluidized bed combustion furnace 20, air is blown into the furnace from the air nozzle on the furnace bottom 25 at the bottom of the combustion chamber 30 which is a space for burning the workpiece, A fluidized bed 31 is formed in which the fluidized material floats in a high temperature state. The recycled fuel input from the recycled fuel inlet 22 comes into contact with the high-temperature fluidized material and burns. The air in the fluidized bed 31 is supplied from the air supply port 24 to the wind box 27 and is supplied into the furnace through a number of air nozzles.
Incombustible foreign matter in the furnace is extracted from the foreign matter discharge pipe 26 together with a part of the fluidized material. The foreign material and the fluidized material are conveyed to the separator 29 by the carry-out unit 28 and then separated by the separator 29. Then, the fluidized material is returned again from the fluidized material inlet 23 into the furnace body 21. The foreign matter is transferred to another processing facility.

Next, with reference to FIGS. 1A, 1B, and 2, an air nozzle that is a characteristic configuration of the present embodiment will be described.
The air nozzle 1 has a double tube structure including a cylindrical inner cylinder 2 and an outer cylinder 5.
The outer cylinder 5 is provided such that the lower part thereof is in contact with the furnace bottom 25 and the upper part is closed.
The inner cylinder 2 is provided through the furnace bottom 25, and an opening 4 communicating with the wind box 26 is provided on the lower end side. The upper end of the inner cylinder 2 is joined to the upper surface of the outer cylinder 5.

A jet hole 3 is formed in the upper peripheral surface of the inner cylinder 2. A plurality of the ejection holes 3 exist along the circumferential direction. Further, the ejection holes 3 are provided in a plurality of stages in the vertical direction. The ejection holes 3 are provided in a plurality of stages to ensure the necessary pressure loss. This and can, injection holes 3 adjacent the upper bottom, the FIG. 2 (a), staggered as shown in (b). As a result, the vertical width of the existence range of the ejection holes is reduced, the imbalance of the ejection flow rate can be reduced, and the distance of the air flow path 7 from the lower end of the ejection holes 3 to the air holes 6 is increased. The rectifying effect is also remarkable.
Examples of the shape of the ejection hole 3 include a circular shape, an elliptical shape, and a rectangular shape. The position, number, shape, and opening area of the ejection hole 3 of the inner cylinder 2 are determined by design so that a predetermined pressure loss is mainly generated between the furnace bottom 25 and the combustion chamber 30.

A plurality of air holes 6 are formed in the lower peripheral surface of the outer cylinder 5. The air pores 6 are lower edge straight, lower edge located on the upper surface and the same surface of the furnace bottom 25. A plurality of the air holes 6 exist at a predetermined pitch interval P along the circumferential direction of the outer cylinder 5. The position, number, shape and opening area of the hole 6 of the outer cylinder 5 are determined by design so that the jet flow ejected mainly into the combustion chamber 30 has a predetermined jet length.
Air supplied from the wind box 26 into the inner cylinder 2 through the opening 4 rises in the inner cylinder 2 and is ejected into the outer cylinder 5 from the ejection hole 3. Necessary pressure loss is ensured in the ejection hole 3. Further, the air jetted into the outer cylinder 5 descends the air flow path 7 formed by the inner peripheral surface of the outer cylinder 5 and the outer peripheral surface of the inner cylinder 2 and is horizontally directed toward the combustion chamber via the air holes 6. The fluidized material ejected in the direction and filled in the bottom of the combustion chamber is fluidized.
According to this configuration, since the lower edge of the air hole 6 of the outer cylinder 5 and the upper surface of the furnace bottom 25 are matched, the pocket in the air nozzle 1 can be eliminated, and the stitcher-like foreign matter generated in the combustion chamber is air. The holes 6 are smoothly discharged without being entangled with the holes 6, and the stitcher-like foreign matters can be prevented from staying and accumulating in the vicinity of the air holes 6.

Moreover, the shape of the air hole 6 drilled in the outer cylinder 5 includes a horseshoe shape shown in FIG. 3A, a semicircular shape shown in FIG. 3B, a rectangular shape shown in FIG. However, in the present invention, it is preferable that the upper edge of the air hole 6 has a curved line shape such as a horseshoe shape or a semicircular shape. As described above, when the shape is a curved line, the processing becomes easy and the manufacturing cost can be reduced. Moreover, the site | part with the short pitch interval P of the air hole 3 decreases, and it can suppress that a stitcher-like foreign material pinches | interposes between air holes and is fixed.
Furthermore, it is preferable that the pitch interval P of the air holes 6 of the outer cylinder 5 is larger than the average length of the stitcher-like foreign matters contained in the recycled fuel. As a result, it is possible to prevent the stitcher-like foreign matter from being pinched between the air holes, and thus to prevent foreign matter accumulation around the air nozzle. At this time, the pitch interval P between the air holes 6 of the outer cylinder 5 is preferably 10 to 30 mm. Many stitchers that are generally used have a long side length Ls of about 20 to 40 mm shown in FIG. Therefore, by setting the pitch interval P to 10 to 30 mm, the pitch interval becomes larger than the opening width of the stitcher, and the stitcher can be prevented from being entangled between the air holes.

In order to grasp the foreign material staying state when the fluidized bed combustion furnace 20 provided with the air nozzle 1 of the present embodiment was operated, the following test was performed.
Targeting wire generated from stitcher and cut the tire generated from the screen dregs, as in FIG. 1 and the air nozzle 1 of FIG. 2 described in this embodiment, the air nozzle 51 in FIGS. 7 and 8 as comparative examples using Then, the dispersion test in the fluidized bed and the discharge test to the outside of the system were conducted, and the improvement of the dispersion performance of this example was confirmed by comparing each of them.
In the present embodiment, the shape of the air hole 6 of the outer cylinder 5 is a horseshoe shape (see FIG. 3A), and a circular shape is employed in the comparative example.

  As the test machine, a fluid bed combustion furnace cold model having the same configuration as that of FIG. 4 and having a width of about 0.8 m × depth of 1.0 m × height of 4 m was used. The air supplied from the air nozzle into the fluidized bed is at room temperature. For a static sand height h (see FIG. 4) of 800 mm in the fluidized bed 31, a non-combustible foreign substance (wire and stitcher) of a predetermined concentration is introduced into the furnace at certain time intervals, and after a total amount of The fluidized bed was divided into four sections in the height direction h, fluidized sand for each corresponding section was dug, and the weight of foreign matter distributed there was measured to examine the distribution of incombustible materials in the fluidized bed.

The test results are shown in FIGS. 5A and 5B are graphs showing the distribution state of foreign matter in the present example and the comparative example. FIG. 5A shows a case where the foreign matter is a stitcher, and FIG. 5B shows a case where the foreign matter is a wire.
As shown in FIG. 5A, when the foreign matter is a stitcher, the comparative example has a very high relative concentration ratio in the lowermost layer, and it can be seen that the stitcher stays and accumulates at the bottom of the furnace. FIG. 6A shows a photograph of the bottom of the furnace after discharging the fluidized material in the comparative example. As is apparent from this photograph, a large amount of the stitcher remains in the vicinity of the air nozzle.
On the other hand, in this embodiment, the relative density ratio of the stitcher is a value close to 1 at any layer height, and it can be seen that the segregation of the stitcher is small. That is, it has been found that a uniform and proper dispersion state can be obtained according to this example. FIG. 6B shows a photograph of the bottom of the furnace after discharging the fluidized material in this example. According to this, it can be seen that the stitcher does not remain at the bottom of the furnace as compared with FIG. 6A, and the stitcher is properly discharged from the foreign matter discharge conduit 26 of FIG. 4 during operation.

In addition, when the foreign substance is a wire as shown in FIG. 5B, it can be seen that the relative concentration ratio is close to 1 in both sections in both the example and the comparative example, and the foreign substance dispersion state is relatively good. In this example, the distribution is more linear than in the comparative example, and the distribution of foreign matter is more uniform than in the comparative example. Therefore, it can be said that the present embodiment can also be applied to the wire.
These test results, foreign matter stitcher and wire ya By adopting the configuration of this embodiment is not to accumulate in the furnace bottom, and the dispersion state, it became clear that the better.

The structure of the air nozzle which concerns on the Example of this invention is shown, (A) is a cross-sectional view, (B) is a sectional side view. 1 shows the arrangement of the ejection holes of the inner cylinder of the air nozzle shown in FIG. 1, (a) is a sectional view taken along the line aa in FIG. 1 (B), and (b) is a sectional view taken along the line bb in FIG. It is. The air hole shape of the outer cylinder of the air nozzle shown in FIG. 1 is shown, (a) shows a horseshoe shape, (b) shows a semicircular shape, and (c) shows a rectangular shape. It is a sectional side view which shows the whole structure of a fluidized bed combustion furnace. It is a graph which shows the distribution condition of the foreign material in a present Example and comparative example obtained by the dispersion | distribution test, (a) shows the case where a foreign material is a stitcher, (b) shows the case where a foreign material is a wire. It is the photograph which shows the state of the furnace bottom part after a dispersion test, (a) is a comparative example, (b) is a present Example. It is a sectional side view of the conventional air nozzle. 7 is a cross-sectional view of the air nozzle of FIG. 7, (a) is a cross-sectional view taken along the line cc of FIG. 7, and (b) is a cross-sectional view taken along the line dd.

DESCRIPTION OF SYMBOLS 1 Air nozzle 2 Inner cylinder 3, 3a, 3b Ejection hole 5 Outer cylinder 6 Air hole 7 Air flow path 10 Furnace bottom 20 Fluidized bed combustion furnace 25 Furnace bottom 26 Foreign matter discharge piping 27 Air box 28 Unloading part 29 Separator 30 Combustion chamber 31 Fluidized bed

Claims (1)

An air nozzle structure of a fluidized bed combustion furnace intended for treating recycled fuel containing non-combustible foreign matter having an elongated portion made of stitcher-like foreign matter , wherein a large number of the air nozzles are arranged at the bottom of the combustion chamber furnace, The air nozzle has a double-pipe structure composed of an inner cylinder and an outer cylinder. A blow hole having a pressure loss adjusting function is formed above the circumferential surface of the inner cylinder, and air is disposed below the circumferential surface of the outer cylinder. In the air nozzle structure of a fluidized bed combustion furnace with holes,
Air hole of the outer cylinder, and the upper edge with a curvature linear lower edge is to position the and the straight lower edge straight horseshoe shape or a semicircular shape on the upper surface and the same surface of the furnace bottom,
Furthermore the air pores Mashimashi multiple exist in the circumferential direction of the outer cylinder, the pitch spacing of the air pores is 10 to 30 mm,
On the other hand, there are a plurality of ejection holes of the inner cylinder along the circumferential direction, the ejection holes are provided with a plurality of ejection holes in the vertical direction, and the ejection holes adjacent to the upper and lower sides are arranged in a staggered manner. The air nozzle structure of the fluidized bed combustion furnace.