Denitration system for pyrolyzing urea by utilizing energy of waste heat boiler blowdown system

The invention discloses a denitration system for pyrolyzing urea by utilizing energy of a waste heat boiler blowdown system, and aims to improve the waste heat boiler blowdown system and the denitration system so as to solve the problem that the existing waste heat boiler denitration system needs to be equipped with a high-temperature booster fan. The system comprises a waste heat boiler blowdown system and a denitration system, the waste heat boiler blowdown system comprises a high-pressure steam drum, a medium-pressure steam drum, a low-pressure steam drum, a continuous blowdown flash tank and a regular blowdown flash tank, and the denitration system comprises a Venturi mixer, a urea pyrolysis tank and a waste heat boiler flue; saturated steam generated by a waste heat boiler blowdown system is utilized to extract high-temperature flue gas through a Venturi mixer, and the high-temperature flue gas is fed into a urea pyrolysis tank to pyrolyze urea. Energy of a waste heat boiler blowdown system is fully util