Catalytic cracking secondary light hydrocarbon feeding nozzle and application method thereof

The invention provides a catalytic cracking secondary light hydrocarbon feeding nozzle and an application method thereof. The catalytic cracking secondary light hydrocarbon feeding nozzle comprises an inlet contraction section, a throat section, a mixing expansion section, a mixing cavity, an outlet contraction section and branch outlets, the inlet contraction section, the throat section, the mixing expansion section, the mixing cavity and the outlet contraction section are communicated in sequence; the mixing cavity, the outlet contraction section and the branch outlets are communicated; on the basis of an existing catalytic cracking riser reactor device, a hole does not need to be formed in the wall face of the riser to arrange a nozzle installation sleeve, the catalytic cracking secondary light hydrocarbon feeding nozzle facilitating industrial transformation and application and application are provided, and normal fluidization and conveying of catalyst particles in a pre-rising section are guaranteed; ove