Waste incineration boiler capable of treating flue gas at front end

The utility model discloses a waste incineration boiler capable of treating flue gas at the front end, which comprises a boiler body, an incineration grate, a gravity separator, a water-cooled hearth and a heat exchange mechanism are arranged in the boiler body, the incineration grate is connected with the gravity separator through a burnout section flue, a feed hopper and a slag cooling hopper are arranged on the incineration grate, and the water-cooled hearth is connected with the heat exchange mechanism. The outlet end of the gravity separator is provided with a purified flue, the purified flue is connected with the water-cooling hearth, the water-cooling hearth is connected with the heat exchange mechanism, the heat exchange mechanism is connected with the smoke outlet window, and the smoke outlet window is connected with the water-cooling hearth. The device solves the problems that the sacrifice load required for reducing NOx is large in fluctuation and the reduction effect of a large boiler is not ideal