The flue gas waste heat recovery technology can effectively reduce the heat loss of the exhaust gas and improve the economics of the unit. The design characteristics of the single low-temperature economizer system and the low-cost combined heater system and the application examples in the project are analyzed systematically. After the low-temperature economizer is disassembled

the heater cannot be operated

resulting in the deposition of air preheater. The problem is to propose a separate low-temperature economizer and heater system

which has better energy-saving effect and improves the safety and economy of the unit.