JPH0835610A - Fluidized-bed apparatus - Google Patents

Abstract

PURPOSE:To equalize the pressure loss in the fluidized-bed vessels of a fluidized- bed apparatus, relating to a plurality of fluidized beds each separated from another by a partition and designed to make fluidized particles move from one bed to the next in order, so as to prevent irregularity in the flow rate of the fluidizing gas and keep the fluidization in a favorable condition. CONSTITUTION:The subject relates to a fluidized-bed apparatus in which through a plurality of fluidized-bed vessels 21a, 21b, 21c separated from one another by partitions 20a, 20b fluidized particles are made to move from one bed to the next in order. The bottom plates 23a, 23b, 23c of the respective fluidized-bed vessels 21a, 21b, 21c are lowered in height in sequence while the height from the bottom plate 23a, 23b to the upper end of the partition 20a, 20b is made substantially the same among all the fluidized-bed vessels so as to form a fluidized bed with virtually a uniform height in all of the fluidized-bed vessels 21a, 21b, 21c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed apparatus such as a circulating fluidized bed boiler having an external heat exchanger.

[0002]

2. Description of the Related Art FIG. 2 shows a fluidized bed heat exchanger as a conventional fluidized bed apparatus, and FIG. 3 shows a conventional circulating fluidized bed boiler in which the fluidized bed heat exchanger is used.

As shown in FIG. 3, the circulating fluidized bed boiler is
It is composed of a combustion chamber 1, a cyclone 2, a fluidized bed heat exchanger 3, and a main portion of a stand pipe 4, and combustion air is supplied from blowers 5a, 5b, 5c to the fluidized bed heat exchanger 3 at high speed. A fluid state called a fluidized bed is formed, and the fuel supplied from the fuel supply device 6 is burning. In the circulating fluidized bed boiler, a fluid material such as silica sand is present and circulates in the system formed by the combustion chamber 1, the cyclone 2, the fluidized bed heat exchanger 3 and the stand pipe 4 together with unburned fuel. ing.

The combustion gas and the fluid material are separated by the cyclone 2, and the gas is discharged from the chimney 10 through the convection heat transfer surface 7, the bag filter 8 and the induction fan 9. The fluid material separated by the cyclone 2 enters the fluidized bed heat exchanger 3 through the stand pipe 4, is cooled by the heat transfer surface inside, and then is heated in the combustion chamber 1.
Recycle to. Particles remaining in the boiler are discharged outside the system by the ash extraction device 11 as needed.

As shown in FIG. 2, the fluidized bed heat exchanger 3 has a plurality of fluidized tanks 21a, which are divided by partition walls 20a and 20b.
21b and 21c (three chambers in the figure) are formed. The fluidizing air is supplied from the blower 5c shown in FIG. 3 to the fluidized bed heat exchanger 3 below the fluidized tanks 21a, 21b and 21c.
Bottom plates 23a, 23b, 23c arranged at the same height inside
The air enters the air chambers 22a, 22b, 22c formed by the above, and is supplied into the flow tanks 21a, 21b, 21c from the flow nozzles provided in the bottom plates 23a, 23b, 23c.
In the fluidized tanks 21a, 21b, 21c, the heat transfer surface 24a,
24b and 24c are provided so as to receive heat from the flowing particles.

As shown in FIG. 3, the lower end of the stand pipe 4 connected to the cyclone 2 opens into the flow tank 21a on the left side in FIG. 2, and the height of the partition wall 20a is higher than that of the partition wall 20b. Has become. Therefore, it is separated by the cyclone 2 and passes through the stand pipe 4 and the fluidized tank 21a.
The fluid material supplied inside forms a fluidized bed in the fluid tank 21a up to the height defined by the partition wall 20a, and the overflowing fluid material next rises up to the height defined by the partition wall 20b in the fluid tank 21b. The fluidized material forming the fluidized bed and further overflowing forms a fluidized bed in the fluidized tank 21c, and circulates to the combustion chamber 1 through the opening surface 25. Therefore, the flow tank 21
In a, 21b, and 21c, a fluidized bed having a relatively low bed height is formed in which the heights are successively lowered.

[0007]

In the above-mentioned conventional fluidized bed heat exchanger, a plurality of fluidized tanks having a low fluidized bed height with respect to the cross-sectional length of the same heat exchanger are formed side by side. The height of the fluidized bed is controlled by the difference in partition height.

The height of the fluidized bed is lowered (i) the pressure loss of the fluidized bed is kept low, and the power required for fluidization (air pressure) is kept low. (Ii) The amount of fluid material held in the fluidized bed heat exchanger should be minimized to improve the response speed when conditions are changed. And the reason.

However, since the height of the fluidized bed is low, the difference in the height of the fluidized bed caused by the difference in the height of the partition walls, that is, the pressure loss difference between the fluidized tanks cannot be ignored with respect to the pressure loss in the portion forming the fluidized bed. Like As a result, the flow rate of the fluidizing gas (generally air) supplied to each of the plurality of fluidizing tanks varies, which may cause a poor fluidized state.

The present invention is intended to provide a fluidized bed apparatus capable of solving the above problems.

[0011]

According to the present invention, there is provided a fluidized bed apparatus having a plurality of fluidized vessels divided by partition walls, wherein fluidized particles sequentially move between the plurality of fluidized vessels. It is characterized in that the height of the bottom plate of the tank is decreased successively, and the height from the bottom plate of each of the flow tanks to the upper end of the partition wall is formed almost equal.

[0012]

In the present invention, the heights of the bottom plates of a plurality of fluidized tanks in which fluidized particles sequentially move are sequentially reduced, and the heights from the bottom plates of the respective fluidized tanks to the upper ends of the partition walls are formed to be approximately equal. Therefore, a plurality of fluidized beds are formed by partition walls having different heights at the upper end, and fluidized beds of substantially the same height are formed in the plurality of fluidized vessels in which fluidized particles sequentially flow. Therefore, the pressure loss of each fluidized tank in which fluidized particles sequentially flow is approximately equalized, uneven flow rate of the fluidizing gas is less likely to occur, and accordingly, the poor fluidized state is less likely to occur.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIG. The present embodiment relates to a fluidized bed heat exchanger as a fluidized bed device used in the circulating fluidized bed boiler shown in FIG. 3 similarly to the conventional fluidized bed heat exchanger shown in FIG. The conventional fluidized bed heat exchanger shown in FIG. 2 is improved as described below. In FIG. 1, the same parts as those in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted.

The fluidized bed heat exchanger 3 has a fluidized tank 21a divided into partition walls 20a and 20b from left to right in FIG.
21b and 21c are formed, and the flow tank 21a on the left side is formed.
The stand pipe 4 is opened in the upper part of the inside, and the right side fluid tank 21c is arranged on the side of the opening surface 25 provided on the side wall of the fluidized bed heat exchanger 3.

The bottom plate 23b of the fluid tank 21b is the fluid tank 21a.
Lower than the bottom plate 23a of the bottom of the flow tank 21c
Is lower than the bottom plate 23b of the flow tank 21b, and the height difference between them is equal. Also, the bottom plate 23
The height from a to the upper end of the partition wall 20a that separates the fluid tanks 21a and 21b, the height from the bottom plate 23b to the upper end of the partition wall 20b that separates the fluid tanks 21b and 21c, and the height from the bottom plate 23c to the lower end of the opening surface 25. Are set to be approximately equal.

In this embodiment, the fluid material separated from the combustion gas by the cyclone 2 shown in FIG. 3 is supplied to the fluid tank 21a through the stand pipe 4 and is defined in the fluid tank 21a by the upper end of the partition wall 20a. To form a fluidized bed up to a certain height.
The fluid material overflowing the partition wall 20a next flows into the fluid tank 21b to form a fluidized bed in the same fluid tank 21b to a height defined by the upper end of the partition wall 20b, and the fluid material overflowing the partition wall 20b is It flows into the fluidized tank 21c and forms a fluidized bed within the fluidized tank 21c up to a height defined by the height of the lower end of the opening surface 25.

As described above, from the bottom plate 23a to the partition wall 20a.
Since the height from the upper end of the bottom plate 23b to the upper end of the partition wall 20b and the height from the bottom plate 23c to the lower end of the opening surface 25 are set to be almost equal,
In 1a, 21b, and 21c, the flow tanks having substantially the same height are formed. In this way, since the heights of the fluidized beds in the fluidized tanks 21a, 21b, 21c are almost equal, the fluidized tanks 21a, 21b, 21c are
Since the pressure loss in each of the fluidizing chambers becomes almost equal, it is possible to prevent the fluctuation of the flow rate of the fluidizing gas caused by the pressure loss difference between the fluidizing tanks and the resulting flow failure.

[0018]

As described above, according to the present invention, the fluidized bed apparatus in which the fluidized particles are sequentially moved between the plurality of fluidized tanks partitioned by the partition wall is provided by the constitutions of the claims. In, the height of the fluidized bed formed in each fluidized tank can be made almost equal, and the following effects can be achieved. (1) It is possible to stabilize the fluidized state while suppressing the increase in power required for fluidization to a minimum. (2) Since the increase in the amount of particles held in the heat exchanger can be suppressed to the minimum, deterioration of the responsiveness of the plant can also be suppressed to the minimum. Further, the above effects are useful for improving the performance and reliability of the fluidized bed apparatus and are very useful in practice.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a fluidized bed heat exchanger according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a conventional fluidized bed heat exchanger.

FIG. 3 is a configuration diagram of a circulating fluidized bed boiler in which the conventional fluidized bed heat exchanger is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustion chamber 2 Cyclone 3 Fluidized bed heat exchanger 4 Stand pipe 5a, 5b, 5c Blower 6 Fuel supply device 7 Convection heat transfer surface 8 Bag filter 9 Induction fan 10 Chimney 11 Ash extractor 20a, 20b Partition wall 21a, 21b, 21c Flow tank 22a, 22b, 22c Wind chamber 23a, 23b, 23c Bottom plate 24a, 24b, 24c Heat transfer surface 25 Opening surface

Claims (1)

[Claims] 1. Having a plurality of flow tanks divided by partition walls,
In a fluidized bed apparatus in which fluidized particles sequentially move between the plurality of fluid tanks, the heights of the bottom plates of the plurality of fluid tanks are sequentially decreased, and the height from the bottom plate of each fluid tank to the upper end of the partition wall is increased. A fluidized bed apparatus characterized in that it is formed to have a substantially uniform size.