Flue gas backflow system of waste incineration waste heat boiler

The utility model provides a flue gas backflow system of a waste incineration waste heat boiler. The device comprises an electrostatic dust collector, an electric inlet adjusting air door, a backflowfan, an outlet electric shutoff baffle door, a flue gas check valve, a manual shutoff valve, a flue gas pipe box and an injection pipe nozzle which are sequentially connected from a flue gas outlet ofthe waste incineration boiler, and the injection pipe nozzle is arranged on a flue gas pipe box on the rear side wall of a third flue of the boiler. After flue gas at the tail of the boiler passes through the electrostatic dust collector, part of clean flue gas is extracted by the backflow fan and fed into a rear side wall tube box of a third flue of the boiler, and positive pressure is sprayed into the third flue at a high speed to be disturbed and mixed with high-temperature flue gas in the flue. Backflow flue gas is sprayed into the flue from the middle of the third flue and is fully disturbed and mixed with high-t