How do you optimize FCC yields based on operating conditions?

FCC yield optimization: Temperature - higher riser temperature increases conversion and gas/LPG yield but reduces liquid yield; typical range 510-540C. Catalyst/oil ratio - higher C/O increases conversion and gasoline selectivity. Catalyst activity - fresh catalyst activity optimized for selectivity vs. coke make. Feed quality - higher CCR and metals in feed increase coke and gas, reduce liquid yield. Feed temperature - higher preheat reduces coke and increases conversion. Steam injection - affects contact time and selectivity. Catalyst type - different zeolites give different gasoline/LPG split. Product value drives optimization - maximize gasoline or maximize propylene depending on economics. Operating constraints: regenerator temperature, air blower capacity, wet gas compressor capacity, and product quality specifications.