燃煤锅炉低温省煤器腐蚀失效分析与防控措施

Corrosion failure analysis and preventive measures for low temperature economizer of coal-fired boiler

燃煤锅炉实施脱硝工艺后,其低温省煤器频繁发生腐蚀失效故障,影响装置长周期安全运行。通过失效案例、过程工艺和流动沉积等综合分析,结果表明:燃煤锅炉省煤器的失效是由烟气沉积物堵塞后的局部流动磨损造成的,烟气冷却过程中,烟气产生的黏性硫酸氢铵对飞灰的黏附沉积影响重大。提出了基于流动沉积磨损预测的省煤器设计选材制造方案及控制烟气中硫酸氢铵含量等工艺防控措施。

After the implementation of denitration process for coal-fired boiler,low-temperature economizer of coal-fired boiler frequently suffered from corrosion failure,which affects long-term operation of the unit.Through comprehensive analysis of the failure cases,process technology and flow,the studies indicated that the failure is caused by local flow induced erosion wear after the blockage of flue gas deposition.During the cooling process of flue gas,the viscous ammonium bisulfate produced by flue gas has a great influence on adhesion and deposition of fly ash.Concrete measures were proposed,such as the scheme of economizer design,material selection and manufacturing based on flow induced erosion wear prediction,as well as controlling ammonium bisulfate content in flue gas.