JPH06300222A - Fluidized-bed furnace - Google Patents

Abstract

PURPOSE:To prevent invasion of fluidizing medium to a powder supply nozzle at the time of simultaneously stopping powder supply systems by providing a purging pipe branching from the outlet of an air blower for fluidizing fluidized-bed and joining to the inlet of the nozzle, and a purging valve provided in the pipe. CONSTITUTION:The fluidized-bed furnace comprises a purging pipe 11 branching from the outlet of a fluidizing air blower 4 and joining to the inlet of an ash supply nozzle 9, and a purging valve 12 provided in the pipe 11. When two ash supply systems 5A, 5B are simultaneously stopped, i. e., when switching valves 8A, 8B are simultaneously closed, the valve 12 is opened. Then, part of fluidizing-bed fluidizing air discharged from the blower 4 is supplied to the nozzle 9 through the tube 11 to be blown into a fluidized-bed 2. Thus, fluidizing medium does not intrude into the nozzle 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of types to be pneumatically transported, such as a fluidized-bed boiler that uses different pulverized coal fuels of different coal types and a heavy oil ash fluidized-bed incinerator having a plurality of ash supply systems. The present invention relates to a fluidized bed furnace in which one kind of powder is supplied from a powder supply nozzle to the inside of a fluidized bed through a switching valve and burned.

[0002]

2. Description of the Related Art FIG. 3 is a system diagram showing an example of a conventional heavy oil ash fluidized bed incinerator. In the figure, (1) is the incinerator body, (2)
Is a fluidized bed, (3) is a fluidized air nozzle, and (4) is a fluidizing air blower. Further, (5A) and (5B) are a plurality (2 in the illustrated example) of ash supply system, each of which is constituted by ash transport air blowers (6A) and (6B) and heavy oil ash hoppers (7A) and (7B). And the switching valve (8
It is connected to the ash supply nozzle (9) via A) and (8B). In such a fluidized bed incinerator, air is blown from the lower part of the furnace through a fluidized air nozzle (3) by a fluidizing air blower (4) to fluidize the fluidized medium in the fluidized bed (3). Also, by switching the switching valves (8A), (8B), a plurality of ash supply systems (5A), (5B)
Of these, any one of the heavy oil ash is supplied into the fluidized bed (2) through the ash supply nozzle (9) and incinerated. In this case, since the outlet of the ash supply nozzle (9) opens in the lower part of the fluidized bed (2), the air for ash transportation also contributes to the fluidization of the fluidized medium.

[0003]

In the conventional system shown in FIG. 3, it is assumed that the ash supply system (5A) is operating and the ash supply system (5B) is stopped. Next, when the ash supply system (5A) is stopped and the ash supply system (5B) is operated, there is a time when both of the switching valves (8A) and (8B) are both closed temporarily. . That is, after the switching valve (8A) is opened and the switching valve (8B) is closed, the switching valve (8A) is closed and the switching valve (8B) is opened after the switching valves (8A) and (8B) are both closed. Shifts to the closed state. That is, it is necessary that the switching valves (8A) and (8B) are both closed at least until the ash transport air blower (6B) is activated. Switching valve (8A), (8B)
It is impossible to open at the same time because of the incineration capacity.

When both switching valves (8A) and (8B) are closed, there is no air flow (blowing) in the ash supply nozzle (9), so that the fluid medium (generally sand) in the fluidized bed (2) is removed. ) Enters the ash feed nozzle (9) and often blocks the nozzle. Since the ash supply nozzle (9) is generally arranged under the fluidized bed (2) and opens at the lower part of the fluidized bed, such a situation is likely to occur.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention provides a plurality of types of powder to be pneumatically fed one by one through a switching valve from a powder supply nozzle into a fluidized bed. In a fluidized bed furnace for supplying and burning the powder to the above, a purge pipe branching from an outlet of an air blower for fluidized bed and joining the inlet of the powder supply nozzle, and a purge valve provided in the purge pipe. The present invention proposes a fluidized bed furnace characterized by being equipped with.

[0006]

In the present invention, when the supply of plural kinds of powder is stopped, that is, when the switching valves are all closed,
The purge valve is opened and a part of the air for fluidized bed fluidization is supplied to the powder supply nozzle via the purge line. As a result, the fluid medium in the fluidized bed is prevented from entering the powder supply nozzle, and the powder supply nozzle is prevented from being blocked.

[0007]

FIG. 1 is a system diagram showing an embodiment of the present invention. In this embodiment, a purge pipe (11) is provided that branches from the outlet of the fluidizing air blower (4) and merges with the inlet of the ash supply nozzle (9), and the purge valve (12) is provided in this purge pipe. Is provided. Since the other points are the same as those of the conventional one described with reference to FIG. 3, detailed description thereof will be omitted.

In such a system, when the two ash supply systems (5A) and (5B) are stopped at the same time, that is, when the switching valves (8A) and (8B) are closed at the same time,
Open the purge valve (12). Then, a part of the fluidized-bed fluidizing air that has exited the fluidizing air blower (4) is supplied to the ash supply nozzle (9) via the purge pipe (11) and injected into the fluidized bed (2). Therefore, the fluid medium does not enter the ash supply nozzle (9). Thus, the ash supply system (5
Ash supply nozzle (9) even if A) and (5B) stop at the same time
Blockage is prevented.

Next, FIG. 2 is a diagram showing an example of a circuit for controlling opening / closing by interlocking the switching valves (8A), (8B) and the purge valve (12). The switching valves (8A) and (8B) are opened and closed by the air pressures controlled by the four-way solenoid valves (15A) and (15B), respectively.
It is also guided to (12B), and when the switching valves (8A) and (8B) are closed, the valves (12A) and (12B) are opened, and the switching valve (8
The valves (12A) and (12B) are adapted to be closed when A) and (8B) are opened. And the valves (12A), (12
B) constitutes the aforementioned purge valve (12). Thus, the purge valve (12) will open only when both switching valves (8A), (8B) are closed.

[0010]

According to the present invention, the following effects can be obtained. 1) When switching the type of powder supplied to the powder supply nozzle, even if the supply of both powders is temporarily stopped, the powder supply nozzle can be prevented from being blocked by the fluid medium. 2) Even when the type of powder to be supplied is not changed, it is necessary to stop the powder supply system at the time of maintenance / inspection or failure of the powder supply system. Even in such a case, it is possible to prevent the powder supply nozzle from being blocked.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a circuit for controlling opening / closing by interlocking a switching valve and a purge valve in the above embodiment.

FIG. 3 is a system diagram showing an example of a conventional heavy oil ash fluidized bed incinerator.

[Explanation of symbols]

 (1) Incinerator body (2) Fluidized bed (3) Fluidized air nozzle (4) Fluidization air blower (5A), (5B) Ash supply system (6A), (6B) Ash transportation air blower (7A) , (7B) Heavy oil ash hopper (8A), (8B) Switching valve (9) Ash supply nozzle (11) Purge line (12) Purge valve (12A), (12B) Valve (15A), (15B) Four-way solenoid valve

Claims (1)

[Claims] 1. An air blower for fluidized bed fluidization in a fluidized bed furnace in which a plurality of types of powders to be pneumatically fed are supplied one by one from a powder supply nozzle through a switching valve into a fluidized bed and burned. Fluidized-bed furnace, comprising: a purge pipe branching from the outlet of the above and joining the inlet of the powder supply nozzle; and a purge valve provided in the purge pipe.