In response to the serious damage to the internal components and body of coke burning drum in the 1.1 Mt/a ethylene plant of a petrochemical company as well as the decrease in the settling and separation effect of coke particles, the existing equipment has been renovated. Drawing on the micro cyclone separation technology, this article analyzes the working principle of rotary jet separator. The internal flow field of the rotary jet separator is analyzed through CFD simulation, obtaining the internal flow field of the rotary jet separator and the microscopic liquid phase jet fragmentation and atomization. The dust removal efficiency and particle trajectory of the rotary jet separator under different conditions are compared using a DPM model, and the dust removal efficiency is analyzed. The research results indicate that rotary jet separator has good application prospects in the coke burning drum of ethylene plant.