Industrial furnace denitration system and method

The invention provides an industrial furnace denitration system and method. The system comprises an industrial furnace, a measurement and control system, a liquid ammonia pump and a flow meter, wherein a first convection bank, a denitration reaction section, a third convection bank and an ammonia evaporation and preheater are sequentially arranged in a flue of the industrial furnace from bottom to top, and an ammonia spraying component, a second convection bank and a catalyst bed layer are sequentially arranged in the denitration reaction section from bottom to top; a mixing section pipeline is arranged outside the industrial furnace; the liquid ammonia pump is communicated with an inlet of the ammonia evaporation and preheater through a liquid ammonia pipeline via a flow meter, and an outlet of the ammonia evaporation and preheater is communicated with an inlet of the mixing section pipeline through a pipeline; a flue gas outlet of the industrial furnace is communicated with an inlet of the mixing section pi