Boiler tail gas waste heat recycling device

The utility model relates to a boiler tail gas waste heat recycling device which mainly used for recycling tail gas waste heat of a boiler. The boiler tail gas waste heat recycling device adopts a steel-aluminum composite finned tube as a heat exchange element, and a temperature probe is mounted on the heated surface of a smoke outlet and used for detecting and controlling the wall temperature of the heated surface of the heat exchange element to adjust the opening degree of a three-way valve and water flow of a water pump. The device controls the wall temperature of the heated surface of the smoke outlet to adjust the feed-water temperature and the flow so as to fully recycle smoke waste heat, improves the recycling efficiency of the smoke waste heat, reduces the requirements for materials and further saves the cost. In addition, the smoke volume can be reduced through reduction of the smoke temperature so as to enable the load of a draught fan to be reduced, and electric power is saved.