Correlation between feedstock SARA components and FCC product yields

Daqing, Shengli, Liaohe, Gudao, Dagang and Huabei vacuum residua were subjected to deep solvent fractionation by using the supercritical fluid extraction and fractionation, a novel separation technology recently developed by the State Key Laboratory of Heavy Oil Processing. Each residuum was fractionated to produce deasphalted oil (DAO) at four yield levels: 30, 40, 50 and 60 wt%. The saturates, aromatics, resins and asphaltenes (SARA) composition of each DAO sample was determined, indicating that the saturates and aromatic contents of DAO decreases with increased DAO yield.The DAO samples were reacted in a laboratory scale confined fluidized bed, fluid catalytic cracking (FCC) reactor. The results show that most of the gasoline yields originates from the saturate fraction of DAO. The aromatics fraction of DAO contributes to gasoline and diesel yields. Most of the coke yield is from resin fraction of DAO.Generalized empirical correlations were developed for predicting the FCC gasoline, diesel, light oil and coke yields as a function of feedstock SARA composition. These yield correlations can be used to set the upper limit of feedstock resins content for commercial FCC operations. The implications of feedstock properties on FCC products were discussed.