【摘要】 为降低NOx排放浓度,通过更换低氮燃烧器,增加燃尽风喷嘴,采用分级燃烧技术对一台600 MW对冲燃烧锅炉进行了低氮燃烧改造,使NOx排放浓度由750~900mg/m3降低到350mg/m3以下,同时锅炉飞灰含碳量没有明显变化。改造后在燃尽风全关的情况下NOx排放浓度即可降低40%,且随燃尽风量增大NOx排放浓度继续降低。针对改造后过热器减温水量明显增加问题,提出了采用部分低温过热器置换为省煤器的方案,以降低减温水流量。更多还原

【Abstract】 To reduce the NOxemission,transformation on a 600MW unit opposed firing boiler was performed,by replacing the low NOxburners,adding overfire air(OFA)nozzles and adopting airstaged combustion technology.After the retrofit,the NOxemission decreased from 750-900mg/m3 to lower than 350 mg/m3 and the spray water flow rate of super-heater increased,but the unburned carbon in fly ash had nearly no change.The NOxemission decreased by 40%even the OFA dampers were fully closed,and it kept on decreasing with the increasing OFA. To reduce the significantly increased spray water flow rate,suggestion that parts of the lowertemperature superheater pipes be replaced by economizer pipes was proposed.更多还原