Abstract:

Low inlet flue gas temperature of selective catalytic reduction (SCR) denitrification system under low load condition cannot meet the requirement for the operation of SCR devices. An upanddown classification retrofit for economizer is proposed. The plan can effectively increase the inlet temperature of the SCR denitrification device and meet the requirements of SCR operation without affecting the boiler efficiency and exhaust temperature. The new added primary economizer adopts H finned tube to solve the compact space at SCR exit . After the retrofit, the optimized soot blowing method for boiler can avoid the low flue gas temperature at the SCR exit under the longtime and low load condition, and avoid high flue gas temperature at the SCR exit under rising load condition. Finally, the problems that need to be considered in economizers classifying layout for different types of units are given.

Key words:

SCR, denitrification, inlet flue gas temperature, economizer classification, H finned tube, soot blowing