Over-fire air arrangement method of opposite firing boiler

Abstract

The invention relates to an over-fire air arrangement method, and discloses an over-fire air arrangement method of an opposite firing boiler. The firing manner of the boiler is an opposite firing manner, wherein horizontal over-fire air (8) is arranged by layers and corresponding to each main firing device layer; the horizontal over-fire air (8) is blown into a hearth in a manner of obliquely intersecting with the firing flame direction in the layer; the horizontal over-fire air (8) in each layer is composed of four pieces of over-fire air, and each piece of over-fire air is divided into three parts, and the rigidity of the over-fire air is gradually increased along the firing flame direction; and a layer of vertical over-fire air (9) is arranged above the top firing flame in the hearth, and the layer of vertical over-fire air (9) is in the direction parallel to the firing flame direction. With the adoption of the over-fire air arrangement method of the opposite firing boiler, the high-temperature corrosion of water-cooling walls of sidewalls of the hearth can be effectively solved, and meanwhile, the emission of NOX can be reduced.

Description

technical field [0001] The invention relates to a method for arranging the overburning air, in particular to an arranging method for the overburning air of a combustion boiler whose front and rear walls oppose each other. Background technique [0002] At present, my country's 600MW and 1000MW unit power plant boilers usually use the front and rear wall opposing swirl combustion technology, and hundreds of boilers of this type have been put into operation. It can be seen that the performance of the boiler can meet the design requirements, and it has the advantages of low load, stable combustion, and good regulation. However, this type of combustion boiler is usually only arranged with overfire air above the main burner layer. The burn-off air in this way cannot ensure that the pulverized coal in the furnace is completely burnt under the action of the burner, and the unburned pulverized coal in the furnace will move to the walls on both sides of the furnace, causing erosion of t...

AI Technical Summary

Problems solved by technology

[0002] At present, my country's 600MW and 1000MW unit power plant boilers usually use the front and rear wall opposing swirl combustion technology, and hundreds of boilers of this type have been put into operation. It can be seen that the performance of the boiler can meet the design requirements, and it has the advantages of low load, stable combustion, and good regulation. However, this type of combustion boiler is usually only arranged with overfire air above the main burner layer. The burn-off air in this way cannot ensure that the pulverized coal in the furnace is completely burnt under the action of the burner, and the unburned pulverized coal in the furnace will move to the walls on both sides of the furnace, causing erosion of the water-cooled walls on both sides. The pulverized coal contains sulfur element, which chemically reacts with the iron in the water-cooled wall of the side wall to form ferrous sulfide, which makes the wall thickness of the water-cooled wall thinner and affects the safety of boiler operation

In order to solve the high-temperature corrosion problem of the water-cooled wall of the side wall of the furnace in the later period, the method of arranging the wall-mounted air is usually used to solve the problem. The arrangement of the wall-mounted air is: the front and rear walls of the boiler furnace are respectively close to the left and right sides of the wall. There are several layers of wall-adjacent air arranged symmetrically. By arranging this way of wall-attached air, the burnout of pulverized coal in the furnace can be enhanced, and the high-temperature corrosion of the water-cooled walls on both sides of the wall can be reduced to a certain extent. However, due to this arrangement The rigidity of the wall-attached wind cannot be solved, so that it cannot well cover the heavily corroded area in the middle of the two side walls, so that the high-temperature corrosion problem of the water-cooled wall of the side wall cannot be completely solved. In addition, due to the arrangement of the wall-attached wind The method is: the front and rear walls of the boiler furnace are arranged symmetrically close to the left and right side walls respectively, so that the lack of air in the middle of the furnace is more serious, which affects the combustion of pulverized coal and causes NO X higher emissions

Images