摘要
循环流化床(CFB)锅炉烟气脱硝技术普遍采用选择性非催化还原法(SNCR)。一般在50%~100%负荷工况下,SNCR可实现锅炉NO超低排放。通过对某350 MW CFB锅炉不同负荷工况下NO排放浓度进行摸底试验和分析,当机组负荷在175 MW时,旋风分离器入口温度约750℃;当机组负荷在105 MW时,旋风分离器入口温度仅约640℃,SNCR脱硝反应效率大幅度降低,NO排放超标,氨逃逸浓度较高。为了实现该锅炉在50%以下负荷时NO达标排放,进行了脱硝方案的设计和改造,设计了基于烟气再循环的SNCR-SCR脱硝系统,利用检修工期分两步实施改造,并在第一步完成SCR脱销系统改造时进行深度调峰试验。深度调峰试验表明,100%、75%和50%负荷下的脱硝效率较改造前分别提高4.27%、2.65%和5.70%;30%负荷下的脱硝效率较改造前提高了50%以上。改造后,在30%~50%负荷下的锅炉NO达标排放,氨逃逸率大幅降低,并遏制了改造前空预器堵灰问题。采用该脱销方案可实现机组30%~100%负荷下NO达标排放,为机组能够参与深度调峰提供了保障,为企业实现了较大的经济效益和社会效益。
Selective non-catalytic reduction(SNCR)is widely used in flue gas denitration technology of circulating fluidized bed(CFB)boiler.Generally,under 50%~100%load conditions,SNCR can achieve ultra-low NOemission requirements of boilers.The NOemission concentration of a 350 MW CFB boiler under different load conditions was tested and analyzed.When the unit load was 175 MW,the inlet temperature of cyclone separator was about 750℃.When the unit load is 105 MW,the inlet temperature of the cyclone separator is only about 640℃,and the reaction efficiency of SNCR denitrification is greatly reduced,NOemission and ammonia escape rate exceed the standard.In order to achieve the standard emission of NOwhen the boiler is under 50%of the load,the denitrification scheme is designed and transformed,and the transformation scheme is determined as flue Gas Recirculation+SNCR-SCR denitrification technology.The transformation is implemented in two steps according to the maintenance period,and the deep peak shaving test is carried out when the SCR selling system transformation is completed in the first step.The deep peak shaving test after the transformation shows that the denitrification efficiency under 100%,75%and 50%load is increased by 4.27%,2.65%and5.70%respectively compared with that before modification.The denitrification efficiency under 30%load is more than 50%higher than that before transformation.After the transformation,the boiler NOemission under30%~50%load is up to standard,ammonia escape rate is greatly reduced,and the ash blocking problem of the air preheater before the transformation is alleviated.The standard emission of NOunder 30%~100%load of the unit can be achieved by the denitration scheme,which can provide guarantee for the unit to participate in the deep peak shaving,and realize great economic and social benefits for the enterprise..
作者
刘军
汪瑞平
宫恩蒙
LIU Jun;WANG Rui-ping;GONG En-meng(Shaanxi Energy Linbei Power Generation Co.,Ltd.,Linyou 721500,China)
出处
《电力学报》
2022年第4期318-323,共6页
Journal of Electric Power
