Denitration device and denitration method thereof

The invention discloses a denitration device. The denitration device comprises a liquid ammonia evaporating tank, a blending tank, a denitration reactor and a draught fan, wherein an ammonia excretion tank is connected onto the liquid ammonia evaporating tank, and connected with a wastewater treating pond; an ammonia injection grid is arranged in the connecting flue of the blending tank and the denitration reactor, and comprises main ammonia injection pipes and ammonia injection branch pipes arranged on a flue pipe body; the ammonia injection branch pipes are communicated with the main ammonia injection pipes through connecting pipes; ammonia nozzles are uniformly distributed on the ammonia injection branch pipes; a regulating valve is arranged on each of the connecting pipes; a differential pressure gauge is bridged at the two ends of one regulating valve; all the regulating valves are connected. Liquid ammonia is evaporated into ammonia gas in the liquid ammonia evaporating tank; the ammonia gas is fully blended with air introduced by the draught fan in the blending tank; the blended gas is conveyed into the ammonia injection grid, and injected into the flue by the ammonia injection grid; the opening angle of the regulating valve in the ammonia injection grid is adjusted according to the measured pressure difference by the differential pressure gauge; after ammonia gas and nitrogen oxide are fully blended, the blended gas is conveyed into the denitration reactor to be subjected to reaction. The denitration device is simple in structure and high in denitration efficiency.