对安徽省内一台660MW超超临界机组的空预器冷段垢样和飞灰进行SEM微观形貌分析和XRF、XRD成分分析,并对SCR脱硝反应器出口NOx浓度和氨逃逸分布进行测试.研究发现,该电厂空预器结垢主要是生成粘性液状物硫酸氢铵粘附烟气中的颗粒造成,且垢样成分非常复杂,有一些新的晶体物生成.机组在490MW负荷下,A、B侧反应器出口NOx浓度分布分别为64.9%、66.2%,远大于设计值要求,氨逃逸浓度分别为3.47、6.36μL/L,均超过设计值要求.提出通过定期喷氨优化是解决空预器堵塞的有效方法,对大型燃煤机组的脱硝运行及机组安全稳定运行有一定的指导作用.%The scale and fly ash samples of air preheater were analyzed by SEM, XRF and XRD from a 660MW supercritical unit of coal-fired power plant in Anhui province.The concentration of NOx and ammonia in the outlet of the SCR reactor were field tested.The results show that the fouling in air preheater of the power plant was mainly generated by the adhesion of particles of flue gas with viscous liquid ammonium hydrogen sulfate.The composition of scale sample was very complicated and there were some new crystal generated.The concentrations of NOx in the outlet of reactor A and B under the 490MW unit were 64.9% and 66.2%, respectively, which were greater than design value.The concentrations of ammonia escape were 3.47μL/L and 6.36μL/L, respectively, which were also larger than design value.The method of spraying ammonia regularly is an effective way to solve the air preheater clogging, which could be helpful for the safety and stability of units in the coal-fired power plants.
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