Spraying device for slowing down contamination and dust deposition of heating surface of waste incineration waste heat boiler

The invention discloses a spraying device for slowing down contamination and ash deposition of a heating surface of a waste incineration waste heat boiler, which comprises an additive conveying system, a compressed air conveying system and a spraying system, the additive conveying system comprises a silica sol adding system, an aluminum sol adding system and a water conveying system; the silica sol adding system, the aluminum sol adding system and the water conveying system are connected to a main pipeline in parallel and then are connected with the spraying system; the silica sol adding system, the aluminum sol adding system and the water conveying system are respectively provided with corresponding switch valves; the compressed air conveying system is communicated with the spraying system; and one end of the spraying system extends into the flue gas channel. The additive solution is sprayed into the high-temperature flue gas to capture alkali metal melt in the flue gas, and accumulated dust on the surface o