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

Abstract

To solve the problem of low reheat steam temperature after low NOx 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.

Keywords

• coal-fired boiler
• low nox retrofit
• reheat steam temperature
• combustion adjustment