600MW机组对冲燃煤锅炉尾部CO浓度偏高的调整试验

Operation optimization on high CO emissions of a 600MW unit swirl-opposed firing boiler after low-NO_x burner retrofitting

某超临界600 MW机组旋流对冲燃烧锅炉低氮改造后,由于运行调整不理想,致使锅炉尾部C O浓度偏高且N Ox 排放未达到预期目标.分析认为,其主要原因是锅炉沿炉膛宽度及深度方向氧量分布不均所致.对此,根据燃烧器改造后的结构特点,对燃烧器参数进行优化调整,在保证NOx 排放的前提下将锅炉满负荷时尾部 CO 浓度由2000μL/L 左右降至100μL/L以下,飞灰可燃物含碳量降至0．5％以下,锅炉效率提高0．8百分点,NOx 排放浓度由改造前的400~450 mg/m3降至250 mg/m3左右.

After low-NOx burner transformation of a supercritical 600 MW swirl-opposed firing boiler,the CO concentration in the tail became high and the NOx emission didn＇t reach the expectations due improper operation adj ustment.The analysis shows that the uneven distribution of oxygen along the width and depth direction of the furnace is the main cause.Thus,according to the structural characteristics of the retrofited burners,the burner parameters were optimized.After that,the CO concentration at rated load reduced from 2 000μL/L to lower than 100μL/L,the carbon content in fly ash reduced to below 0.5%,the boiler effi-ciency increased by 0.8%,and the NOx emission concentration dropped from 400~450 mg/m3 to about 2 5 0 mg/m3 .