Heating medium liquid type smoke-air heat exchanger

The utility model relates to a heating medium liquid type smoke-air heat exchanger which comprises a smoke cooling heat exchanger and a steam air heater. A heating medium liquid outlet of the smoke cooling heat exchanger is communicated with a heating medium liquid inlet of the steam air heater. A heating medium liquid outlet of the steam air heater is communicated with a heating medium liquid inlet of the smoke cooling heat exchanger. A circulating pump capable of achieving heating medium liquid cold and hot circulation is arranged between the smoke cooling heat exchanger and the steam air heater. A constant pressure device and a water compensating device are further arranged between the smoke cooling heat exchanger and the steam air heater. Heat is transferred to the steam air heater through the smoke cooling heat exchanger by using boiler exhausted smoke waste heat so that temperature of cold air entering a boiler air preheater is raised, the phenomena of low temperature corrosion and scaling blocking are effectively avoided, meanwhile, boiler smoke emitting temperature is reduced, and the problem that smoke exhausting temperature of a common steam air heater is increased is solved. The heating medium liquid type smoke-air heat exchanger is simple in structure and capable of achieving the purpose of using the smoke waste heat to the maximum extent, enabling a boiler to be economic and operate in high heat exchange efficiency and achieving the aims of saving energy, reducing consumption and reducing emission.