Method and system for reducing NO discharging by collecting and refiring fine coal powder in tertiary wind

Abstract

The invention is a method and system for decreasing the NOX discharge by burning the tiny coal powder in the third wind. The third wind containing tiny coal powder is separated and condensed. At the separation, the third wind is divided into two beams: one is rich coal powder flow, another one is rare coal powder flow, the rich coal powder flow is used as fuel and transmitted into the furnace, the rare coal powder flow is used as the burned wind aperture arranged on the reiguition area. Then forms a secondary combustion area of the rich fuel, thus it reacts with the NOX in the primary combustion area and reduces the NOX discharge quantity. The merits of the invention are: 1) the temperature of the third wind is low, the water is rich, the combustion state of the tiny powder can be improved, the ash combustible substance can be decreased, the efficiency of the boiler can be upgraded; 2) it is arranged on the top of the combustor, it need not to change the primary combustor, the height of the fire center will not be changed, and the affection to the steam is little; 3) the particle size is tiny, it need not to increase ultrathin powder grinder; 4) the NOX discharge quantity can be decreased about 40-50%.

Description

technical field [0001] The invention relates to a method and system for reducing NOx emission by collecting and reburning fine coal powder in tertiary air. Background technique [0002] The use of reburning technology can significantly reduce NOx emissions. The essence of reburning technology is staged combustion technology. Boiler furnace is divided into main combustion zone, reburning zone and burnout zone from bottom to top. About 80% of the fuel is sent to the main combustion zone, where it burns to generate NOx in an environment with sufficient oxygen (that is, α>1). The remaining 20% ​​of the fuel is sent to the reburning zone to form an oxygen deficient reducing atmosphere with α<1. The NOx generated in the main combustion area undergoes a reduction reaction in a reducing atmosphere and finally generates N 2 , In the upper part of the reburning zone, there is a "fire upper wind" (burning wind) to ensure the complete combustion of c...

AI Technical Summary

Problems solved by technology

Due to its low temperature and high water content, the third stop of the wind often results in the increase of fly ash combustibles and the fluctuation of steam temperature

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