关键词: 提质褐煤, NOx排放, 水分, 煤粉细度, 燃尽风位置比, 主燃风率, 燃尽风率

Abstract: Lignite resources are rich in China. The advanced drying technology makes their large-scale utilization possible. The firing tests for four kinds of Baorixile dried lignite with different water contents are carried out under different proportions of staged air, different inlet positions of burnout air and different pulverized coal fineness in a one-dimension boiler with multipath air inlet. The results indicate that first, air-staged combustion can lower the NO_x emissions of the lignite substantially; second, to achieve the best result of NO_x emission control, the water content of the lignite is recommended as 0.9% to be the most adequate; third, through combustion adjustment and optimization, the NO_x emission level from the combustion of the lignite can be reduced to 250-300 mg/m³; and fourth, when designing a boiler firing dried lignite, attentions should not only be paid to the proportions of staged air and the positions of burnout air, but also to the coal powder fineness and the water content.

Key words: dried lignite, NOx emission, water content, coal fineness, burnout air position, primary combustion air rate, burnout air rate