The document presents a study on a ten lump model for simulating a Fluid Catalytic Cracking (FCC) riser reactor, analyzing the impact of various feedstock compositions on gasoline and coke yields. Using C++ programming and the Runge-Kutta-Fehlberg method, it predicts gasoline yields of 72% for naphthenic feedstock compared to 67% for paraffinic and 59% for aromatic feeds at a space time of 4.5 seconds. The study also incorporates factors such as catalyst decay, nitrogen poisoning, and temperature effects on yield conversions.