MODELLING OF FCC PROCESS BASED ON CLUSTER SIZE VARIATION ALONG THE RISER

Fluid catalytic cracking (FCC) is an important petroleum process to convert heavy petroleum cuts into light cuts such as gasoline and LPG. In this work، a steady state one dimensional model of FCC riser using a 4-lump kinetic model was presented. Equations for mass، momentum and energy balance were written and coded by MATLAB. The model was written based on the upward movement of catalyst particles in the riser in a cluster formation. The modeling was based on the assumption that the clusters diameters were not constant، but varies all along the riser. Using the model، product yields، temperature profile in the riser، gas and solid velocity، catalyst decay rate and change in cluster diameter along the riser were investigated. The accuracy of the model was validated by 4 industrial cases that reported in the literature. The obtained results at the end of riser showed to be in good agreement with industrial data by average percentage error of 3. 12% for gasoline yield، 5. 35% for coke yield and 1. 81% for riser temperature. The results showed a decrease in percentage error when they were compared with the assumption of the constant cluster diameter along the riser.