JPS61119904A - Burning of coal burning boiler - Google Patents

Abstract

PURPOSE:To contrive to decrease the NOx produced from an N content in a coal by a method wherein flames from burners arranged in a furnace of a coal burning boiler are concentrated on the required location in the furnace, the flame temperature is raised and the N contained in the coal is gasified speedily together with volatile matters. CONSTITUTION:By inclining a burner 2b downward and a burner 2c upward respectively located at upper and lower side of a horizontal burner 2a, a flame 3 is concentrated on the extended line of the horizontal burner 2a. A burning air window box and an ash discharging port are indicated by 4 and 5, also the inclining angle of the burner 2 is contrived to be adjusted as shown by an arrow mark A. A pulverized coal supplied through each burner 2 is heated rapidly, a N contained in the coal is gasified together with volatile matters, accordingly, the stabilizing ratio in a form of N2 is increased, therefore, the NOx generated by the N content contained in the coal can be decreased, and the amount of NOx contained in whole exhaust gas can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a combustion method for a coal-fired boiler, and particularly to a combustion method for reducing NOx.

[Conventional technology 1] In a coal-fired boiler, by increasing the flame temperature and changing the ratio of NOx (Volatile NOx) due to volatile content to NOx (CharN○×) due to coal solid content, the temperature at the boiler outlet is reduced. It has been confirmed that NOx'a levels can be reduced.

It has been found that the higher the temperature, the faster N in coal comes out together with volatile matter. Therefore, NOx can be reduced by increasing the combustion temperature to quickly release N from the coal and reducing it to N2 in the furnace.

However, in the conventional coal-fired boiler, there is no effective means for specifically increasing the flame temperature.

[Problem to be solved by the invention 1] In other words, for example, in a coal-fired boiler, in order to increase the flame temperature, it is also considered to reduce the mutual spacing between burners, which are conventionally installed in large numbers horizontally, to perform intensive combustion. However, there is a problem in that each burner is connected to a large structure such as a combustion air duct, and it is not possible to narrow the interval due to hardware.

The present invention aims to reduce NOx by tilting the horizontal burner, which was the conventional concept, to concentrate combustion and increase the flame temperature.

Means for Solving Problem c] The present invention has been made in an attempt to solve the above-mentioned technical problem, and it concentrates the flame from the burner provided in the furnace of a coal-fired boiler at a predetermined position in the furnace. The present invention relates to a combustion method for a coal-fired boiler, which is characterized in that combustion is performed by increasing the temperature.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

The drawing shows an example of the present invention, in which a burner 2 provided in a furnace 1 of a coal-fired boiler is tilted so that its flame 3 is concentrated at a predetermined position inside the furnace. In the illustrated case, by tilting the upper burner 2b of the horizontal burner 28 downward and tilting the lower burner 2C upward, the horizontal burner 2
The flame 3 is concentrated on the extension line of a. In the figure, 4 indicates a wind box for combustion air, and 5 indicates an ash discharge port. Incidentally, the burner 2 may be configured such that its inclination angle can be adjusted as shown by arrow A.

As mentioned above, two inclined burners and three flames
is concentrated at the desired location within the furnace, resulting in a significantly higher flame temperature than would be the case with a parallel burner arrangement. For this reason,
The pulverized coal supplied from each burner 2 is rapidly heated, and the rate at which N in the coal is released together with volatile matter and stabilized in the form of N2 increases. Therefore, NOx due to N content in coal
(Fuel NOx> is reduced, and N in the entire exhaust gas is
Ox will be reduced.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and that the number of burners, the selection of burners to be inclined, and the angle of inclination can be arbitrarily determined, and that the present invention can be applied to combustion in various coal-fired boilers, and that the details thereof can be changed. Of course, various changes may be made without departing from the gist of the invention.

[Effects of the Invention] As described above, according to the combustion method for a coal-fired boiler of the present invention, the flame from each burner is concentrated at a predetermined position within the boiler large flame, thereby increasing the flame temperature and causing combustion. This makes it possible to reduce NOx in exhaust gas by causing N in the coal to come out quickly together with the volatile matter and reducing NOx due to the N content in the coal, which was difficult to do in the past. When put into practice, it can be easily carried out with a simple configuration of only tilting the burner, and other excellent effects can be achieved.

[Brief explanation of drawings]

The drawing is an explanatory diagram showing an example of a furnace of a coal-fired boiler in which the method of the present invention is implemented. 1 is a furnace, 2 is a burner, 3 is a flame, 4 is a wind box for combustion air, and 5 is an ash outlet. Patent application Hitoshi Kawajima Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1) A combustion method for a coal-fired boiler, characterized in that the flame from a burner provided in the furnace of the coal-fired boiler is concentrated at a predetermined position in the furnace to raise the flame temperature and cause combustion.