660 MW SCR脱硝机组空预器堵塞原因分析及对策

Analysis on Air Preheater Blockage of 660 MW SCR Denitration Units and the Countermeasures

SCR装置氨逃逸,特别是在低温低负荷运行条件下,极易造成喷氨过量,在空预器冷端生成NH4HSO4,是导致空预器堵塞的主要原因。此外,煤质、空预器冷端壁面温度、催化剂活性、低负荷等因素也是导致空预器堵塞的原因。对此,提出了改进SCR系统、锅炉低负荷时燃烧调整、空预器吹灰冲洗方式调整等建议来改善空预器堵塞状况。

The ammonia slip from SCR denitration device , especially in low temperature and low load opera-tion, can easily cause the excess ammonia injection and form NH4HSO4 at the cold end of air preheater, re-sulting in air preheater blockage. In addition, coal quality , the cold end wall temperature of air preheater , catalyst activity and low load all are causes for air preheater blockage. Therefore , the paper proposes to im-prove SCR system, adjust the combustion of boiler in case of low load and soot-blowing and washing mode of air preheater, for the purpose of mitigating air preheater blockage.