The Art of Evaluating Laboratory Fixed Bed Catalytic Cracking Data

Component Yield – wt%Propylene = - 0.6864X 2 + 4.7667XPropane = 0.422Xn-Butane = 0.315Xi-Butane = 1.4567Xi-Butylene = - 0.4825X 2 + 2.3586Xn-Butylenes = - 0.663X 2 + 4.0906XFor all of these relationships, X = 2 nd order conversion.Using these relationships, the gasoline yield over a range of conversions can be determined bydifference. Table 1 illustrates this approach, using conversions at 50, 66.7, 75, and 80 wt% (1.0, 2.0, 3.0,and 4.0 2 nd order conversion). The individual yields at these conversions are shown in the table. Thegasoline yield at these conversions is then obtained by subtracting the sum of these products from therelated conversion.Table 1Gasoline Yields for Product A – ACE Catalyst TestingObtained by Difference from Product Yields for Catalyst AConversion – wt% 50.0 66.7 75.0 80.0Conversion – 2 nd Order 1.00 2.00 3.00 4.00Product Yields – wt%Coke 1.65 3.11 4.56 6.02H 2 0.064 0.086 0.107 0.129C 1 0.48 0.62 0.76 0.89C 2 + C 2 = 1.03 1.19 1.36 1.53Σ Dry Gas 1.57 1.90 2.23 2.55C 3 = 4.08 6.79 8.12 8.08C 3 0.42 0.84 1.27 1.69Σ C 3 s 4.50 7.63 9.39 9.77nC 4 0.31 0.63 0.94 1.26iC4 1.46 2.91 4.37 5.83iC 4 = 1.88 2.79 2.73 1.71nC 4 = 3.43 5.53 6.30 5.75Σ C 4 s 7.08 11.86 14.34 14.53==== ===== ==== ====Σ C 4 - + Coke 14.80 24.50 30.52 32.89Gasoline = Conv – (ΣC 4 - + Coke) 35.20 42.17 44.48 47.11