JPS595541B2 - Coal combustion method in vertical firing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coal combustion method in a vertical calciner for calcining limestone, dolomite magnesite and other similar raw materials.

Conventionally, combustion methods using pulverized coal have been adopted in horizontal rotary furnaces, but in double cylindrical vertical furnaces, the fuel supply means, combustion management, and sintering management are complicated, so pulverized coal is not used. However, combustion methods using oil or gas were used instead.

FIG. 1 shows a conventional double cylindrical vertical kiln.

An inner cylinder 2 is arranged concentrically inside an outer cylinder 1.

A raw stone input port 3 is provided at the upper end of the outer cylinder 1, through which limestone, dolomite, magnesite, and other similar raw materials are input.

The upper end of the outer cylinder 1 is connected to an exhaust gas fan 4 to discharge combustion exhaust gas outside the outer cylinder 1, and a part of it is guided to a recuperator 5 as hot gas for preheating.

The upper end of the recuperator 5 is connected to the upper end of the inner cylinder 2, and the lower part of the recuperator 5 is connected to a ring pipe 6 that supplies combustion air, and combustion air preheated to a predetermined temperature is supplied.

A ring pipe 7 is arranged outside the ring pipe 6 to collect and supply cooling air for the inner cylinder 2.
At the same time, air is supplied to an upper burner 8 and a lower burner 12 which are provided in the middle of the outer cylinder 1 and which burn oil or gas.

Inside the outer cylinder 1, there are a plurality of upper combustion chambers 9 and a plurality of lower combustion chambers 10. In the lower combustion chambers 10, part of the combustion gas flows upward as shown in the figure, and the remaining combustion gas flows downward parallel to the raw material. The injector 11 is used to suck the cooling air that has risen from the lower part of the outer cylinder 1 into the lower end of the inner cylinder 2.
is provided.

The upper part of the injector 11 is connected to a ring pipe 6 that supplies combustion air, and the lower end communicates with a lower combustion chamber 10 in which a lower burner 12 is provided.

The lower burner 12 is supplied with air from the ring pipes 6 and 7 and burns oil or gas.

In such a conventional vertical firing furnace, the lower burner 1
If 2 is replaced with a pulverized coal combustion burner and pulverized coal is burned, the ash of the pulverized coal will be mixed into the product to be fired, resulting in a product containing many impurities.

Further, if a method of directly injecting pulverized coal into the combustion chamber is adopted, the means for supplying pulverized coal, combustion management, and combustion management are too complicated and impractical.

The present invention provides a method for burning coal in a vertical firing apparatus configured so that even if pulverized coal is used as fuel and other liquid and gaseous fuels are co-fired, coal ash is not easily mixed into the product.

An embodiment of the coal combustion power method of the present invention will be described below with reference to the drawings.

FIG. 2 shows a schematic configuration of a firing furnace employing the method of the present invention.

In the figure, parts that are the same as or correspond to those in FIG. 1 are indicated by the same reference numerals, and their explanation will be omitted.

In this embodiment, a cyclone type hot air stove 13 is provided.

This hot air stove 13 is provided with a plurality of pulverized coal burners 14 in a tangential direction in its combustion chamber, and also has a recuperator 5.
A portion of the heated air is tangentially blown in to create a vortex inside the hot blast stove.

15 is a pulverized coal production equipment, where pulverized coal with small particle size is produced, and the pulverized coal hopper 1
6.

The hopper 16 has a quantitative supply feeder 17, and the pulverized coal sent out from the feeder 17 is supplied by an ejector 19 equipped with a blower 18 to the pulverized coal burner 14 provided in the cyclone type hot blast furnace 13 described above.

The pulverized coal ash burned in the hot blast furnace 13 is separated from the hot air by the cyclone action and falls along the furnace wall.

This fallen ash is discharged from an air locker 20 provided at the lower end.

The hot air generated in the hot air stove 13 is supplied to the ring pipe 6' that supplies the combustion air described above, and is used as working air for the injector 11.

Since this embodiment is configured as described above, pulverized coal is burned in a cyclone hot blast furnace placed outside the firing furnace, and
The ash is discharged without being led into the combustion furnace,
It will not mix with the material to be fired in the furnace and reduce the quality of the product.

The pulverized coal used for combustion accounts for 20% of the total heat of the kiln.
The gas generated in the hot stove is approximately 13
It is 00℃.

Further, the circulating gas drawn into the furnace from the injector 11 is used as tertiary air in the lower combustion chamber 10 to consume approximately 66 times the total amount of heat.

Therefore, since the amount of heat combusted in the cyclone-type hot air stove 13 is 20% or more of the total amount of heat, the remaining 80% or less of the amount of heat required in the lower combustion chamber 10 is often dependent on oil or gas. .

As a result, 34% of the total heat amount in the upper burner 8 is covered by oil or gas fuel.

As is clear from the above description, according to the coal combustion method of the present invention, pulverized coal is combusted in a cyclone hot air furnace placed outside the firing furnace, ash of the pulverized coal is separated from hot air, and the ash is The generated heat is used as tertiary air in the lower combustion chamber of the firing furnace, so pulverized coal ash does not mix into the product and reduce purity, resulting in high-quality fired products. Since the amount of heat supplied by pulverized coal reaches one fourth of the required amount of heat, running costs can be significantly reduced.

Although a cyclone type hot air stove has been described as an example above, a stoker type hot air stove can also achieve the same effects as the cyclone type hot air stove.

Still, each of the above embodiments has a configuration in which a hot blast furnace is attached to a vertical (single-barrel) firing furnace, but the vertical firing furnace is not only a single-barrel type, but also a double-barrel type or a multi-tilt type. Also, the same effects as those of the above-mentioned embodiments can be achieved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional double cylindrical vertical firing furnace, and FIG. 2 is a schematic diagram of an embodiment in which the coal combustion method of the double cylindrical vertical firing apparatus of the present invention is implemented. . 1 is an outer cylinder, 2 is an inner cylinder, 3 is a raw stone input port, 4 is an exhaust gas fan, 5 is a recuperator, 6 is a ring pipe (for recuperator heating air), 7 is a ring pipe (for cooling air in the middle cylinder), 8
is an upper burner, 9 is an upper combustion chamber, 10 is a lower combustion chamber, 1
1 is an injector, 12 is a lower burner, 13 is a cyclone type hot air furnace, 14 is a pulverized coal burner, 15 is a pulverized coal production device, 16 is a hopper, and 19 is an ejector.

Claims (1)

[Claims] 1 A hot blast furnace is placed outside the vertical firing furnace, pulverized coal is supplied to this hot blast furnace and combusted, ash separated from the generated hot air is discharged from the hot blast furnace, and only the hot blast is used as working air for the injector. A coal combustion method using a vertical firing device.