To improve the ignition behavior and to reduce the high NO_x emissions of blended pulverized fuels (PF) of semicoke (SC), large-scale experiments were conducted in a 300 kW fired furnace at various nozzle settings, i.e., ratios (denoted by h_f/b) of the height of the rectangular burner nozzle to its width of 1.65, 2.32, and 3.22. The combustion tests indicate that the flame stability, ignition performance, and fuel burnout ratio were significantly improved at a nozzle setting of h_f/b = 2.32. The smaller h_f/b delayed ignition and caused the flame to concentrate excessively on the axis of the furnace, while the larger h_f/b easily caused the deflection of the pulverized coal flame, and a high-temperature flame zone emerged close to the furnace wall. NO_x emissions at the outlet of the primary zone decreased from 447 to 354 mg/m³ (O₂ = 6%), and the ignition distance decreased from 420 to 246 mm when the h_f/b varied from 1.65 to 3.22. Furthermore, the ratio (denoted by S_R/S_C) of the strong reduction zone area to the combustion reaction zone area was defined experimentally by the CO concentration to evaluate the reduction zone. The S_R/S_C rose monotonously, but its restraining effects on NO_x formation decreased as h_f/b increased. The results suggested that in a test furnace, regulating the nozzle h_f/b conditions sharply reduces NO_x emissions and improves the combustion efficiency of SC blends possessing an appropriate jet rigidity.

为了改进点火性能和降低高NO _X混合粉状燃料（PF）的半焦（SC），大型实验在300千瓦进行了排放量在各个喷嘴设置燃烧炉，即比（记为ħ _f / b）的矩形燃烧器喷嘴的高度为其宽度1.65、2.32和3.22。燃烧测试表明，在喷嘴设置为h _f / b = 2.32时，火焰稳定性，点火性能和燃油燃尽率得到了显着改善。h _f / b越小，点火延迟时间越长，并导致火焰过度集中在炉膛轴线上；而更大的h _f / bh _f / b容易引起煤粉火焰的偏转，并且靠近炉壁的地方出现了高温火焰区。当h _f / b从1.65变为3.22时，主要区域出口的NO _x排放量从447降至354 mg / m ³（O ₂ = 6％），点火距离从420降至246 mm 。此外，通过CO浓度通过实验确定强还原区面积与燃烧反应区面积之比（以S _R / S _C表示），以评价还原区。该小号_{- [R} /S _C单调上升，但随着h _f / b的增加，其对NO _x形成的抑制作用降低。结果表明，在试验炉中，调节喷嘴的h _f / b条件可显着减少NO _x排放并提高具有适当射流刚度的SC混合物的燃烧效率。