Preheating of air and flue gas waste heat utilization system

The utility model discloses special preheating of air technical field to the boiler. The utility model discloses a preheating of air and flue gas waste heat utilization system, include: flue gas passageway (17), air duct (20), air heater (9), condensate water flue heat exchanger (8) and condensate water air duct heat exchanger (19) still include: the condensate water comes water header (15), condensate water return main (12), flue gas passageway (17) and air duct (20) all link to each other with air heater (9), condensate water flue heat exchanger (8) is arranged on flue gas passageway (17) behind air heater (9) along flue gas flow, condensate water air duct heat exchanger (19) is along the air current to arranging on air heater (9) preceding air duct (20). The utility model discloses the heat transfer of can discharging fume according to service condition's change automatically regulated realizes receiving under the prerequisite of hot side safety and system's normal operating guaranteeing, ensures the maximize of thermodynamic cycle efficiency and the economic nature of system.