CFB锅炉设计煤种燃烧特性试验研究

Experimental Study on Combustion Characteristics of the Design Coal for a CFB Boiler

在3 MW循环流化床(CFB)燃烧试验台上,进行了某CFB锅炉设计煤种在不同负荷和一、二次风配比下的燃烧试验,研究了床温和投入石灰石对炉内燃烧稳定性以及污染物排放特性的影响.结果表明:设计煤种着火温度为436℃,床温在780℃时炉内仍能保持稳定运行;投入石灰石能有效提高炉内脱硫效率,但会使燃烧效率降低;中断给煤10min后重新给煤,仍可自行恢复到正常运行工况;设计煤种自脱硫效率可达38%,当Ca与S物质的量比为3.7时,床温发生波动时脱硫效率为88.2%~95.1%;负荷和一次风率对炉内NO_x生成量影响较大,通过调节负荷和一次风率,NO_x排放质量浓度可降至100mg/m^3以下.

To investigate the effects of bed temperature and limestone on the combustion stability and pol- lutant emission of a CFB boiler, combustion tests were conducted in a 3 MW CFB boiler combustion test bed at different loads and different primary to secondary air ratios burning the design coal. Results show that the ignition temperature of design coal is 436℃ and stable operation can be kept in the test bed when the bed temperature is 780 ℃. Limestone can improve the desulfurization efficiency, but would decrease the combustion efficiency. If the coal feed is interrupted for ten minutes, normal operation could still be recovered automatically after the coal feed continues again. The self-desulfurization efficiency of design coal gets up to 38%, while its desulfurization efficiency lies in 88.2%-95.1% for the Ca/S mole ratio of 3.7 in the case of bed temperature fluctuation. The load and primary air ratio effects more on NOx generation than other factors, and the NOx emission can drop down to 100 mg/m^3 through reasonable adjust- ments on the load and primary air ratio.