EFFECT OF FEEDSTOCK VARIABILITY ON CATALYTIC CRACKING YIELDS

Nine compositionally distinct vacuum gas oil feedstocks have been studied to develop a rational basis for understanding the distribution of major products in fluid catalytic cracking (FCC) reactions. Key hydrocarbon and carbon types have been quantitated from mass spectrometric data. Product yields were determined, under standardized conditions, using an FCC microactivity test (MAT) system. Severity conditions were varied to obtain yield profiles encompassing that MAT conversion where the yield of C5F+ gasoline was at maximum. These optimum yield profiles were correlated with the feedstock properties which characterized and quantitated those precursors capable of producing gasoline molecules. The correlations were tested against two further vacuum gas oils. The conclusions are that realistic comparisons between feeds may be made at conversions where the yield of gasoline is at maximum. © 1990.