JPH0133723B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coal feeding device for a fluidized bed boiler.

In a fluidized bed boiler, a combustion chamber is filled with a fluidized medium made of inert granular material such as sand, and fluidized air is injected into the combustion chamber from the bottom of the combustion chamber. In this method, coal and other combustible materials are fed into the fluidized bed formation area and burned. Heat exchanger tubes are placed in the fluidized bed formation area, and the The fluid passed through the fluidized bed exchanges heat with the heat generated by combustion of the combustible material supplied into the fluidized bed forming area, thereby generating hot fluid or steam.

When supplying coal as fuel to a fluidized bed boiler, there is a method that involves pumping fine coal together with air into the fluidized bed, but this method requires the labor of drying and pulverizing the coal to convey it through air. .

In addition, when supplying coal as fuel to a fluidized bed boiler without pulverizing or classifying it, there is a method in which the coal is fed into the fluidized bed from the surrounding wall of the cavity of the combustion chamber using a spreader coal feeding device. Wet coal may be used as it is, but if it is not classified, it usually contains a large amount of pulverized coal, and this pulverized coal is burned in the empty column or discharged to the outside of the combustion chamber in an unburned state along with the rising airflow, reducing combustion efficiency. The disadvantage is that it worsens.

Therefore, if a combined coal feeding system using both pneumatic conveyance and spreader coal feeding systems is to be adopted, a classifier for classifying fine coal containing pulverized coal and lump coal will be required, and it will be necessary to prevent clogging of the classifier. Therefore, it is necessary to dry the coal in advance.

The present invention has been made in view of the above points, and there is no need to dry or classify coal in advance, and it is supplied by a spreader coal feeder, while fine coal is separated and supplied into a fluidized bed. This is how it was done.

Embodiments of the present invention will be described below based on the drawings.

The fluidized bed boiler consists of a combustion chamber cavity 1, a fluidized bed 2, and a wind box 3.

Fluidizing air is supplied from the wind box 3 to the bottom of the fluidized bed 2 to fluidize the fluidized medium within the fluidized bed 2.

Exhaust gas is discharged from the upper part of the empty column part 1.

A coal feeding device is installed adjacent to this fluidized bed boiler,
Coal feeding openings 4 and 5 are provided in the combustion chamber surrounding wall of the fluidized bed boiler at two locations above and below the empty column section 1 and the fluidized bed 2.

A fuel conveying air pipe 6 is connected to the opening 5 provided in the fluidized bed 2, and the fuel is forced into the fluidized bed 2 by air.

A fuel injection opening 4 provided in the empty tower section 1 is connected to a spreader coal feeder, and the spreader coal feeder 7 has a feeder 8 at the top and a rotor 10 of the spreader below the feeder 8. The impeller 1 is rotatably provided in the rotor 10.
1 is provided, and this rotor 10 and impeller 1
1 is lined with wire mesh.

A hopper 9 is provided below between the rotor 10 and the tower opening 4, and the lower end of the hopper 9 is connected to the middle of the fuel conveying air pipe 6.

A movable partition plate 12 for adjusting the height of the opening 4 is provided in the above-mentioned cavity opening 4 so as to be movable up and down in order to adjust the size of the coal that is introduced from the opening 4 onto the fluidized bed 2. There is.

Next, we will explain the operation of this coal feeding device.
Supplying fluidized air from the wind box 3 of the fluidized bed boiler,
The fluidized medium in the fluidized bed 2 is fluidized, and the exhaust gas is discharged from the upper end of the column 1.

Thermal coal is fed from the outside by a feeder 8 and falls onto the spreader coal feeding device 7.

Thermal coal can be coal of various sizes.

As the rotor 10 rotates, an impeller 11 splashes the falling coal and throws it onto the fluidized bed 2 from the empty column opening 4.

At this time, relatively large lump coals jump over the partition plate 12 and are supplied onto the fluidized bed 2 from the cavity opening 4.
2 or does not reach the sky tower opening 4,
It falls into a hopper 9 provided between the rotor 10 and the combustion chamber surrounding wall.

The fine coal containing pulverized coal that has fallen into the hopper 9 in this way is forced into the fluidized bed 2 together with the air sent to the fuel conveying air pipe 6, and is combusted in a mixed state with the fluidized medium.

As described above, the present invention provides a spreader coal feeder adjacent to a fluidized bed boiler, and among the coals fed by the spreader coal feeder, large-diameter coal that is considered to be lump coal is transported between the rotor and the combustion chamber. The coal jumps over the hopper installed between the surrounding wall and is fed onto the fluidized bed through the opening in the sky column.On the other hand, coal with a small diameter and short flight distance, which is considered fine granule coal, and pulverized coal are fed into the hopper. Since the coal is sucked into the fuel conveying air pipe and fed into the fluidized bed, it is unnecessary to dry, classify, crush, etc. the coal for coal feeding, simplifying the equipment and improving maintainability. Furthermore, the size of the coal charged onto the fluidized bed can be determined by adjusting the height of the opening of the column by moving the movable partition plate up and down, which improves fuel classification accuracy and improves combustion efficiency. It is effective in increasing the combustion efficiency and also prevents a reduction in combustion efficiency due to scattering of pulverized coal, making it extremely effective as a coal feeding device for a fluidized bed boiler.

[Brief explanation of drawings]

FIG. 1 is a side sectional view for explaining the present invention, and FIG. 2 is a partial perspective view of the main parts of the spreader coal feeding device. 1... Combustion chamber empty column, 2... Fluidized bed, 3... Wind box, 4
... Sky column opening, 5... Fluidized bed opening, 6... Air pipe for fuel conveyance, 7... Spreader coal feeder, 8... Feeder, 9... Hopper, 10... Rotor, 11... Impeller.

Claims (1)

[Scope of Claims] 1. In a fluidized bed boiler in which a spreader coal feeding device is provided adjacent to the fluidized bed boiler, openings for coal feeding are provided in two locations, one in the empty column part of the fluidized bed boiler and the other in the fluidized bed part,
A rotor with an impeller of a spreader pulverized coal device is provided at a distance from the opening of the empty tower, a hopper is provided below between the rotor and the opening of the empty tower, and the lower end of the hopper is connected to the fluidized bed opening. 1. A coal feeding device for a fluidized bed boiler, characterized in that a movable partition plate is connected to a tube and provided at an opening of a hollow column portion to adjust the height of the opening. 2. The coal feeding device for a fluidized bed boiler according to claim 1, wherein the impeller is covered with a wire mesh surface.