JPH10160101A - Burner control method for coal fired boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide stable boiler characteristics without use of a burner tilt apparatus by employing an upper stage side burner nozzle when coal has a low fuel ratio while enpolying a lower stage side burner nozzle when coal has a high fuel ratio, and switching the burner nozzles within boiler loads in response to the same. SOLUTION: In low fuel ratio coal with a fuel ratio of 1.3 or lower for example, a coal burning boiler 1 uses 2nd to 6th burner nozzles at a 100% load, 3rd to 6th stage burner nozzles 2 at a 75% load, 3rd to 5th stage burner nozzles 2 at a 50% load, and 3rd to 4th stage burner nozzles at a 30% load, while in standard coal and high fuel ratio coal with a fuel ratio of 1.3 or more it uses 1st to 5th stage burner nozzles 2 at a 100% load, 2nd to 5th stage burner nozzles 2 at a 75% load, 2nd to 4th stage burner nozzles 2 at a 50% load, and 2nd to 3rd stage burner nozzles 2 at a 30% load to combust coal. Switching of the burner 2 use stage with the fuel ratio is automatically performed. For this even when kinds of coal are different, the amount of absorption of heat in a furnace becomes the same, and hence stable boiler characteristics are ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a burner of a coal-fired boiler using various kinds of coal.

[0002]

2. Description of the Related Art Coal has a fuel ratio (solid carbon /
Volatile fraction) and are classified into low fuel ratio coal, standard coal, and high fuel ratio coal. Coal-fired boilers are characterized in that the amount of heat absorbed in the furnace changes depending on the type of coal, and the boiler characteristics fluctuate greatly.

In a conventional coal-fired boiler, a burner tilt device 3 shown in FIG. 2 has been used in order to minimize fluctuations in boiler characteristics due to differences in coal types and to enable stable boiler operation.

A burner tilt device 3 shown in FIG. 2 shows a burner applied to a six-stage coal-fired boiler, and is controlled by a control device 4 to move the burner nozzle 2 up and down according to the type of coal, and Are intended to stabilize the characteristics.

[0005] The burner use stage can be properly used depending on the state of the boiler load, but the first to fifth stages at 100% load, the second to fifth stages at 75% load, and the second at 50% load. 4th stage, 2nd and 3rd stages are used at 30% load (the burner use stages are the first, second, third, fourth, fifth and sixth stages from the bottom).

[0006]

In a conventional coal-fired boiler, as described above, a burner tilt device is used to reduce fluctuations in boiler characteristics due to a difference in coal type, thereby moving a burner nozzle up and down. Was corresponding.

However, this burner tilt device has a problem that the structure is complicated and the price is high. The present invention seeks to solve the above problems.

[0008]

According to a first aspect of the present invention, there is provided a method for controlling a burner of a coal-fired boiler, the method comprising: burning coal having different fuel ratios; If the coal to be burned is low-fuel-ratio coal, use the upper burner nozzle; if it is high-fuel-ratio coal, use the lower-burner nozzle, and switch the burner nozzle within each range according to the boiler load. It is characterized by:

[0009] In the above, since the fuel ejected from the burner nozzle burns while rising inside the furnace, the fuel ejected from the lower stage burns better and the furnace absorbs a large amount of heat. On the other hand, low-fuel-ratio coal has more volatile components than high-fuel-ratio coal, and therefore burns well and has a large amount of heat absorbed by the furnace.

In the present invention, the burner nozzle on the upper stage is used in the case of low fuel ratio coal, and the lower burner nozzle is used in the case of high fuel ratio coal. As a result, stable boiler characteristics can be obtained without using a burner tilt device.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for controlling a burner of a coal-fired boiler according to one embodiment of the present invention will be described with reference to FIG.

In this embodiment, the boiler has six burner nozzles, and the respective stages are the first, second, third, fourth, fifth and sixth stages from the bottom. One stage is reserved.

In the present embodiment shown in FIG. 1, for a low fuel ratio coal having a fuel ratio of 1.3 or less, the coal-fired boiler 1
Use 2nd to 6th stage at 00% load, 3rd to 6th stage at 75% load, 3rd to 5th stage at 50% load, 3rd to 4th stage at 30% load In the case of standard coal having a fuel ratio of 1.3 or more and high fuel ratio coal, the first to fifth stages, 75 at 100% load
% To 2nd stage at 50% load, 2nd to 4th stage at 50% load
It is assumed that coal is burned using the second and third stages at 30% load and the burner use stage is automatically switched according to the fuel ratio.

In the above description, the fuel ejected from the burner nozzle 2 rises in the furnace while burning, so that the fuel ejected from the lower burner nozzle 2 has a longer combustion time than that ejected from the upper stage and has the same coal type. In the case of, the heat absorption of the furnace is large.

On the other hand, low-fuel-ratio coal has a large amount of volatile matter and burns well, so that the furnace has a large heat absorption. Since the furnace is inferior to charcoal, the furnace absorbs less heat.

In the present invention, in the case of low fuel ratio coal,
The upper burner nozzle 2 is used, and in the case of high fuel ratio coal, the lower burner nozzle 2 is used. Therefore, even if the coal type is different, the heat absorption of the furnace becomes the same, and stable boiler characteristics are obtained. And a burner tilt device is not required.

[0017]

According to the method for controlling a burner of a coal-fired boiler of the present invention, when the coal to be burned is low-fuel-ratio coal,
By using the upper stage side of the multiple stage burner nozzles, and in the case of high fuel ratio coal, using the lower stage burner nozzles to switch the burner nozzles according to the boiler load, in any case, Since the heat absorption amounts of the furnaces are equivalent, stable boiler characteristics can be obtained without using a burner tilt device.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a burner control method for a coal-fired boiler according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional burner control method.

[Explanation of symbols]

 1 boiler 2 burner nozzle

Claims (1)

[Claims] Claims 1. A coal-fired boiler provided with a plurality of burner nozzles for burning coal having different fuel ratios,
If the coal to be burned is low-fuel-ratio coal, use the upper burner nozzle; if it is high-fuel-ratio coal, use the lower-burner nozzle, and switch the burner nozzle within each range according to the boiler load. A method for controlling a burner of a coal-fired boiler, comprising: