To solve the problem of coke powder entrainment towards the main fractionator in a delayed coking unit, an open scrubbing tower can be installed instead of filtration. Based on a particle scavenging model, a gas-liquid-solid three-phase numerical method was adopted to simulate the process of particle removal. Besides, the effects of particle size, droplet size, gas velocity, and droplet flow rate are quantitatively assessed using the genetic aggregation response surface method. The results indicate that the formation of a liquid film can promote the heat transfer and particle removal. The collection efficiencies of interception and diffusion are much less than that of impaction. After response surface analysis, the local sensitivity of operating parameters and the optimized point are obtained.