关键词: 选择性催化还原, 流场, 催化剂, 喷氨, 故障诊断

Abstract: Taking the SCR(selective catalytic reduction) system in a 330-MW power plant as an example, the concentration and flow distribution measurement and catalyst detection are carried out to solve the problems occurred during the operation, such as the high ammonia escape rate, the large pressure difference of the air preheater and the high NOx concentration deviation between the SCR outlet and the stack inlet. The results show that the uneven flow distribution is the major cause for catalyst corrosion, and the decreased activity of the catalyst and the unreasonable ammonia injection contribute to the fault of the SCR system. Through optimal adjustment of the ammonia injection, the distribution of SCR outlet NOx concentration is improved and the ammonia escape is reduced. Meanwhile, suggestions for the SCR system upgrading are proposed based on the diagnosis analysis.

Key words: selective catalytic reduction, flow distribution, catalyst, ammonia injection, fault diagnosis