• • Increasing ejection gas velocity from 12 to 16 m/s reduces fine particle proportion in coarse fraction from 14% to 12%, directly improving classification sharpness for FCC catalyst separation.
• • Raising bed linear velocity from 0.15 to 0.25 m/s increases pressure drop by up to 15%, with dimensionless standard deviation below 5%, confirming stable operation under varying load.
• • Higher inlet particle concentration (30 to 70 g/m3) shifts cut size dc50 toward smaller diameters, enhancing fine particle removal but risking selectivity loss due to excessive entrainment.
• • Synergistic tuning of ejection gas velocity and inlet concentration enables simultaneous improvement of classification efficiency and selectivity, offering a pathway to optimize catalyst utilization in coupled FCC-pyrolysis units.