Relating gasoline production and coke formation to feedstock composition and operating conditions in fluid catalytic cracking

Gasoline production and coke formation models are proposed for catalytic cracking of petroleum as a function of feed composition and operating conditions. Arabian Heavy Crude was distilled and the cut (650–1012°F) was obtained. This cut was fed to the Micro Confined Bed Unit (MCBU) where it was catalytically cracked using zeolite catalyst. The range of operating conditions in this work is catalyst to oil ratio (C/O) [4–16] and reactor temperature [460–560°C]. Gasoline yield is correlated with conversion and the operating conditions with R2 = 0.9.; Several attempts were made to predict the conversion to be able to use the gasoline model. Two groups of data were involved in the conversion modeling: data from this work with different operating conditions (C/O ratio and the reactor temperature), and data from Green et al. with different feedstock parameters. The Amoco model was found to be the best existing model for correlating the operating conditions to predict the conversion. The proposed conversion correlation gives a satisfactory fit to the data. The proposed correlations are able to predict conversion <80% and gasoline <50%, which is the conventional FCC normal operating practice.; Coke formation also is modeled using the same two groups of data. Regression analysis for these data gives R2 = 0.89.; Experimental results show that gasoline increases with C/O to a maximum value and then decreases. Paraffins, iso-paraffins and hydrogen in the gas product increase with C/O ratio while olefins and H₂S decrease. Increasing the reactor temperature increases the olefins, hydrogen production, methane and ethane while C₃–C₅ paraffins, isoparaffins and H₂S decrease with temperature. This work shows also that increasing the C/O ratio increases coke yield while increasing temperature decreases coke yield.