低氮改造后再热汽温偏低的燃烧调整研究

针对某330 MW燃煤锅炉低氮改造后出现的再热汽温偏低问题，从锅炉燃烧调整策略角度进行对策研究，主要分析了燃烧器摆角、配风方式、燃烧器投运层分布、上层煤种、上层煤粉细度、水平烟道吹灰和机组自动调节品质等因素对再热汽温的影响。结果表明，再热汽温偏低的现象主要出现在锅炉中低负荷（250 MW以下）工况，通过增加燃烧器仰角、采用倒宝塔配风方式、提高上层燃烧器利用率、加大上层入炉煤发热量、减小上层入炉煤粉细度、加强水平烟道吹灰和优化机组自动调节品质等手段可改善再热汽温偏低问题。提出的燃烧调整策略对同类锅炉改造问题具有重要借鉴意义。

Study on Low Reheat Steam Temperature After Low NOx Retrofit Based on Combustion Adjustment

To solve the problem of low reheat steam temperature after low NO_x retrofit in a 330 MW coal-fired boiler, the countermeasure study was conducted based on combustion adjustment strategies. The effects of burner angle, air distribution mode, burner layer distribution, coal type of upper layer, coal fineness of upper layer, ash blowing of horizontal flue, and automatic control quality on reheat steam temperature were analyzed. The results indicate that the low reheat steam temperature mainly occurs at medium-low load (lower than 250 MW). Increasing burner angle, using inverted tower air distribution, increasing utilization rate of upper burner, improving coal calorific of upper layer, decreasing coal fineness of upper layer, strengthening ash blowing of horizontal flue and optimizing automatic control quality are conducive to improving the reheat steam temperature. The proposed combustion adjustment strategies provide important reference for the similar problem in boiler retrofit.