Controlling the NO_x formation during the combustion process is the most direct and efficient way to minimize NO_x emissions, so low NO_x combustion technology is essential. In this work, in order to develop multi-air staging pulverized coal (PC) preheating-combustion technology and further optimize the preheating-combustion burner, a 35 kW PC preheating-combustion test system was built, and three types of burners with different outer secondary air (OSA) injection structures were designed. Using Huangling bituminous coal (HL coal) and Wuhai bituminous coal (WH coal), the coupling process of PC preheating-combustion with multi-air staging on NO_x emissions was studied systematically. The results showed that the depth furnace air staging could further reduce NO_x emissions. When close-coupled over-fire air (CCOFA) and separated over-fire air (SOFA) were applied simultaneously, a significant NO_x reduction of 70.2% could be reached 217 mg m⁻³. Compared with the NO_x emissions, the unburned carbon in fly ash presented opposite tendency. Compared to burner II (high-speed swirl jet) and III (low-speed axial jet), burner I (high-speed axial jet) showed the lowest NO_x emissions under the multi-air staging preheating-combustion conditions. Furthermore, the depth furnace air staging had greater denitrification potential for high-quality bituminous coal.

控制NO _X在燃烧过程中形成的最直接，最有效的方式，以尽量减少NO _X的排放量，所以低NO _X燃烧技术是必不可少的。在这项工作中，为了开发多级粉煤预热燃烧技术并进一步优化预热燃烧器，建立了一个35 kW PC预热燃烧测试系统，并设计了三种类型的具有不同外部燃烧器的燃烧器设计了二次空气（OSA）喷射结构。利用黄陵烟煤（HL煤）和乌海烟煤（WH煤），PC预热燃烧与多级空燃对NO _x的耦合过程对排放进行了系统的研究。结果表明，深度炉内空气分级可以进一步减少NO _X排放。当紧密连接的过度燃烧空气（CCOFA）和分离过火灾空气（SOFA）同时施加一个显著NO _X还原的70.2％可以达成217毫克米^-3。与NO _x排放相比，粉煤灰中未燃烧的碳呈现相反的趋势。相比燃烧器II（高速旋流喷射）和III（低速轴向喷射），燃烧器I（高速轴向喷射）显示了最低的NO _X的多空气分级预热燃烧条件下的排放。此外，深度炉空气分级对于高质量烟煤具有更大的反硝化潜力。