切圆燃烧锅炉低负荷NO_x生成浓度偏高的原因及措施

Cause Analysis and Prevention Plans on High Concentration NO_x Production at Low Load in Tangentially-Firing Utility Boilers

低负荷下NOx生成浓度较高是燃用高挥发分煤种切圆燃烧锅炉普遍存在的问题,理论分析与试验研究表明:在中、低负荷区间,燃烧初期空气/燃料比的增加是NOx生成浓度升高的重要原因;在理论分析与试验研究的基础上,对周界风控制方式进行了创新性改进,通过控制不同负荷下周界风的挡板开度,在锅炉效率不变、汽温参数不受影响的前提下,显著降低了中、低负荷区间的NOx生成浓度。

The problem of high concentration NOx produced at low loads is quite general in tangentially-firing boilers using high volatile coal. The theoretical analysis and field tests indicate that under medium and low loading conditions, as the air to fuel ratio richens in the initial firing stage the NO~ concentration increase substantially. Therefore, a new fuel air damper control scheme is proposed, in which the damper opening is adjusted at different loads. Consequently, NOx production is significantly reduced at low loads with the boiler efficiency and steam temperatures hardly affected.