JP2002221302A - Circulating fluidized bed boiler with wear preventing mechanism for evaporating pipe of furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circulating fluidized bed boiler with a wear preventing mechanism for an evaporating pipe of a furnace having a simple constitution. SOLUTION: The wear of the evaporating pipes 2 of the furnace with fluidized material particles is suppressed by reducing the amount of the particles which deposit on the upper surface of a refractory material 3 and descend along the internal wall of the furnace by covering the gap between the upper parts of the evaporating pipes 2 from the upper surface of the refractory material 3 covering the internal lower part of the furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circulating fluidized bed boiler, and more particularly to a circulating fluidized bed boiler having a wear prevention mechanism for a furnace evaporating tube.

[0002]

2. Description of the Related Art A furnace of a conventional circulating fluidized bed boiler has a substantially rectangular longitudinal section, the furnace bottom is narrowed in a pyramid shape, and the lower inside of the furnace is covered with a refractory material to prevent abrasion of the evaporating tube. ing. 1 and 2 are cross-sectional views of a conventional circulating fluidized-bed boiler, in which (a) is a longitudinal section, and (b) is A-
A section, (C) shows BB section, and (D) shows details of C section.

[0003] That is, the inside of the lower part of the furnace evaporator tube 2 arranged around the furnace 1 is covered with a refractory material 3 in order to prevent abrasion by the fluid material particles. However, the flow material particles that collided with the upper end of the refractory material 3 and bounced back, or the flow material particles swirling between the furnace evaporator tubes 2 may cause the thinning 6 to occur in a specific range of the furnace evaporator tube 2. Was.

That is, the fluid material particles are naturally deposited mainly on the upper surface of the refractory material 3 between the furnace evaporator tubes 2 at an angle of repose θ with the upper surface of the refractory material 3. In the portion 6 where the slope 5 having the angle of repose θ intersects the surface of the furnace evaporator tube 2, wall thinning easily occurs. In particular, the wall thickness was remarkable because the fluidized material particles were concentrated at the furnace corner. Although the reason for this is not necessarily elucidated, in addition to the fact that the fluidized material particles tend to concentrate in the narrow portion between the furnace evaporator tubes 2, the amount of the fluidized material particles directly rebounding to the inside of the furnace is small.
One of the reasons is that the amount of rebound in the direction is large, and they flow again inside the furnace and come into contact with the furnace evaporating tube 2 more frequently.

[0005] In order to reduce wall thinning, metal spraying may be performed on the furnace evaporation tube 2 or the height of the refractory material may be increased.

[0006]

However, since it is difficult to perform metal spraying on the corners, it cannot be avoided that the sprayed material at the corners is easily peeled off. further,
Raising the refractory material increases production costs. The present invention has been made in view of the above problems, and an object of the present invention is to provide a circulating fluidized bed boiler having a simple structure for preventing wear of a furnace evaporator tube.

[0007]

SUMMARY OF THE INVENTION A circulating fluidized bed boiler according to the present invention is a circulating fluidized bed boiler in which a lower portion inside a furnace is covered with a refractory material, and descends along the inner wall of the furnace above an upper surface of the refractory material. It is provided with a particle entry suppressing means for suppressing entry of the fluidized material particles between the furnace evaporation tubes. In the present invention, the particles of the fluidized material are suppressed from entering between the furnace evaporating tubes by the particle entry suppressing means.

[0008]

FIG. 3 is a partially enlarged view of a furnace of a circulating fluidized-bed boiler according to the first invention. The furnace evaporator tubes 2 are welded to each other through heat conducting fins 4 to surround the furnace. Placed in The lower part of the furnace evaporation tube 2 is covered with a refractory material 3. According to the first aspect of the present invention, the wear-resistant fins 30 are attached to the upper surface of the refractory material 3 between the furnace evaporating tubes 2 by welding or the like to prevent the flow material particles from entering the narrow portion between the furnace evaporating tubes 2. It is something that was prevented.

The abrasion preventing fins 30 are preferably arranged from the upper surface of the refractory material 3 to the furnace ceiling. Alternatively, the heat conductive fins 4 may be directly contacted. FIG. 4 is a cross-sectional view of the furnace of the circulating fluidized-bed boiler according to the first invention, taken along line CC. FIG. 4E shows a case where the wear prevention fins 30 are arranged in parallel with the heat conduction fins 4 in the horizontal direction. (F) shows a case where the wear preventing fins 30 at the corners are obliquely arranged in order to prevent the fluid material particles from depositing at the corners.

In the above embodiment, the wear preventing fins are provided on the entire circumference of the furnace. However, the wear preventing fins may be provided only at the furnace corners where the fluid material particles are likely to stay. Further, in the above embodiment, the wear preventing fin is made of steel plate and is assumed to be welded to the furnace evaporating tube. However, the wear preventing fin may be configured by embedding a refractory material in a gap between the furnace evaporating tube. . In this case, it is needless to say that the upper surface of the embedded refractory material is inclined inward from the contact portion with the heat conducting fin 4.

FIG. 5 is a partially enlarged view (g) and a DD sectional view (h) of a furnace of the circulating fluidized bed boiler according to the second invention. It is installed by welding or the like. Then, a gap 51 is secured between the wear prevention fin 50 and the refractory material 3. In this case, the fluid material particles stay at a high density in the gap between the heat conducting fins 4 and the wear preventing fins 50, and the speed of the fluid material particles is reduced. Since the amount of wear of the furnace evaporator tube 2 is proportional to the third to fourth power of the velocity of the fluidized material particles, the amount of wear of the furnace evaporator tube 2 due to the fluidized material particles is reduced.

The heat conducting fins 4 and the wear preventing fins 5
The fluid material particles retained in the gap 0 are gradually discharged from the lower gap 51 into the furnace. FIG. 6 is a partially enlarged view (I) and a sectional view (N) of the furnace of the circulating fluidized-bed boiler according to the third invention. The wear preventing fins 60 are vertically divided into two parts with a slit 61 therebetween. Are installed between the furnace evaporation tubes 2 in parallel with the heat conducting fins 4.

In this case, the fluid material particles stay at a high density in the gap between the heat conducting fins 4 and the wear preventing fins 60, and the speed of the fluid material particles is reduced. Then, the retained fluid material particles are gradually discharged from the slit 61 into the furnace. FIG. 7 is a sectional view of a furnace of the circulating fluidized-bed boiler according to the fourth invention, which has a structure for essentially removing a narrow space between the furnace evaporator tubes 2 as in the first invention.

That is, (R) shows that the heat conducting fins 4 attached so as to connect the center of the furnace evaporating tube in the first to third inventions are attached to the inside of the furnace and used as wear preventing fins, and the irregularities on the inner wall of the furnace are used. To reduce abrasion due to fluidized material particles. In addition, (e) uses the flat surface of the omega tube, which was not conventionally applied to the furnace evaporator tube, toward the inside of the furnace as an anti-abrasion fin,
Eliminates irregularities on the furnace inner wall and reduces wear due to fluidized material particles.

In the first to third inventions, in order to improve the wear resistance of the wear preventing fin, the wear preventing fin itself may be made of ceramic, or may be made of a general metal material (for example, a steel plate). A wear resistant material may be sprayed on the wear preventing fins.

[0016]

According to the circulating fluidized bed boiler of the present invention, the provision of the particle entry suppressing means makes it possible to suppress the wear of the furnace evaporator due to the flow material particles falling along the furnace inner wall with a simple configuration. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a sectional view of a furnace of a conventional circulating fluidized bed boiler (1/1).
2).

FIG. 2 is a sectional view of a furnace of a conventional circulating fluidized bed boiler (2 /
2).

FIG. 3 is a partially enlarged view of a furnace of the circulating fluidized-bed boiler according to the first invention.

FIG. 4 is a sectional view of a circulating fluidized bed boiler according to the first invention.

FIG. 5 is a partially enlarged view and a sectional view of a furnace of the circulating fluidized bed boiler according to the second invention.

FIG. 6 is a partially enlarged view and a sectional view of a furnace of a circulating fluidized-bed boiler according to a third invention.

FIG. 7 is a sectional view of a furnace of a circulating fluidized-bed boiler according to a fourth invention.

Continuing from the front page (72) Inventor Toshiro Kuroishi 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Sanshi Heavy Industries Co., Ltd. (72) Inventor Toshiaki Nishio 5-717-1 Fukahori-cho, Nagasaki-shi, Nagasaki Prefecture Inside Nagasaki Laboratory Co., Ltd. (72) Inventor: Manabu Miyamoto 1-1-1 Wadazakicho, Hyogo-ku, Kobe-shi, Hyogo F-term in Mitsubishi Heavy Industries, Ltd. Kobe Shipyard 3F064

Claims (9)

[Claims] 1. A circulating fluidized bed boiler in which a lower part inside a furnace is covered with a refractory material, wherein a flow material particle descending along an inner wall of the furnace above an upper surface of the refractory material is prevented from entering between the furnace evaporation tubes. A circulating fluidized-bed boiler provided with a particle intrusion suppressing means. 2. The circulating fluidized-bed boiler according to claim 1, wherein the particle entry suppressing means is a wear prevention fin that extends above the upper surface of the refractory material and covers a gap between the furnace evaporator tubes above the upper surface of the refractory material. . 3. The wear prevention fins, wherein the particle intrusion suppressing means extends upward at a predetermined interval from the upper surface of the refractory material and is disposed inside the furnace between the furnace evaporation tubes above the upper surface of the refractory material. Item 2. A circulating fluidized bed boiler according to Item 1. 4. The wear-inhibiting fins extending above the refractory material upper surface and having a vertical gap inside the furnace between the furnace evaporator tubes above the refractory material upper surface. 3. A circulating fluidized bed boiler according to item 1. 5. The circulating fluidized bed boiler according to claim 2, wherein the wear preventing fin is made of ceramic. 6. The circulating fluidized bed boiler according to claim 2, wherein the wear preventing fins are formed by spraying a wear-resistant material on the inner surface of a furnace. 7. The circulating fluidized bed boiler according to claim 1, wherein the particle intrusion suppressing means is a wear prevention fin that interconnects the furnace evaporator tubes inside the furnace from the center of the furnace evaporator tube. 8. The circulating fluidized bed boiler according to claim 7, wherein the wear preventing fin is a heat conducting fin. 9. The circulating fluidized bed boiler according to claim 7, wherein the wear preventing fin is a connecting portion of a furnace evaporating tube of an omega tube.