After-flaming air nozzle arrangement structure

Abstract

The invention relates to an after-flaming air nozzle arrangement structure used for a wall-type opposed firing pulverized coal fired boiler. The burner region of the front wall and / or rear wall of the wall-type opposed firing pulverized coal fired boiler comprises a multilayer burner, wherein two layers of after-flaming air nozzles are distributed at the upper part of the burner region; the burner region comprises upper-layer main after-flaming air nozzles and lower-layer auxiliary after-flaming air nozzles, and the quantity of the main after-flaming air nozzles or the auxiliary after-flaming air nozzles is same to that of burners on each layer, and each main after-flaming air nozzle or each auxiliary after-flaming air nozzle is aligned with each burner on each layer in the vertical direction; and the discrepancy of the quantities of the two layers of after-flaming air nozzles is one, and the main after-flaming air nozzles are arranged in a staggered manner in the vertical direction relative to the auxiliary after-flaming air nozzles. According to the invention, the total after-flaming air quantity is higher, and a good NOx generation inhibition effect can be achieved; and meanwhile, the two layers of after-flaming air nozzles are in staggered arrangement in the vertical direction, so that the coverage area of after-flaming air stream is increased, the capability of trapping non after-flaming substances in smoke from the after-flaming air stream is enhanced.

Description

technical field [0001] The invention belongs to the technical field of pulverized coal combustion, and in particular relates to an arrangement structure of an overburning air nozzle, which is used in a wall-type opposed combustion pulverized coal boiler. Background technique [0002] Air staged combustion technology is a pulverized coal boiler combustion technology developed in the United States in the 1950s. Its principle is: the combustion process of fuel is completed in stages. In the first stage, the amount of air fed into the furnace from the pulverized coal burner is reduced to 70% to 75% of the total combustion air, so that the fuel can be burned under the combustion conditions of oxygen deficiency and rich fuel. At this time, the excess air coefficient α < 1, thereby reducing the combustion speed and temperature level in the combustion area, not only delaying the combustion process, but also reducing the reaction rate of NOx formation in the reducing atmosphere, ...

AI Technical Summary

Problems solved by technology

[0007] The object of the present invention is to provide an arrangement structure of overfire air nozzles suitable for wall-type opposing combustion pulverized coal boilers, which is used to solve the problems of low combustion efficiency and high-temperature corrosion of side walls that are prone to occur when the overfire air volume is high, so as to realize Its deep air staged combustion can reduce the amount of NOx generated by the boiler without reducing the combustion efficiency

Images