大型循环流化床锅炉NOx超低排放技术的对比研究

Comparative Study on Ultra-Low Emission Technology of NOx in Large CFB Boiler

循环流化床锅炉燃烧温度低,床温区间范围小,一次风率变化范围有限等,燃烧调整手段和影响因素少,在低氮燃烧改造中,只要抓住布风板改造和分离器提效改造两个重点,实现NOx超低排放是比较容易的。四台锅炉及改造方案的对比研究表明:使布风板布风均匀,对不同煤种确定合适的一次风率,提高分离器入口烟气流速,确定适合的中心筒尺寸,从而提高分离器效率,使床温可控,是CFB(循环流化床)锅炉低氮燃烧改造的关键。

CFB boiler combustion temperature is low,the range of bed temperature is small,the range of primary air rate is limited,combustion adjustment means and influencing factors are few,in the low-nitrogen combustion retrofit,as long as put focus on the transformation of the air distributor and the efficiency improvement of the separator,it is relatively easy to achieve ultra-low NOx emission.Through the comparative study of four boilers and retrofit schemes,it is shown that the key to the low-nitrogen combustion transformation of CFB boiler is to make the air distributor uniform,determine the appropriate primary air rate for different types of coal,improve the inlet flue gas velocity of separator and determine the appropriate size of center cylinder,so as to improve the efficiency of separator and make the bed temperature controllable.