Modelling catalytic cracking in a novel Riser Simulator. (Volumes I and II)

A 45 mL bench-scale internal recycle reactor, named a 'Riser Simulator' was used to study the kinetics of catalytic cracking. This reaction system is well suited for riser cracking reactions since it can be operated at reaction times as low as 3 seconds and can simulate the reaction regime of a riser. The reactor operates in a batch mode with a gas recirculation in the upward direction through the central catalyst zone to maintain a well fluidized bed.;Experimental runs performed in the unit included the cracking of two commercial feedstocks and three mixtures of pure light oil compounds with two commercial catalysts. The reactor conditions were varied with temperatures of 500, 525 and 550;The kinetic parameters associated with the three lump model were evaluated based on a reactor model which intrinsically includes the effect of molar expansion during cracking. The kinetic values obtained fell in the range of values reported in other works using pilot scale riser units. Three different catalyst decay functions were used and it was found that first order decay was sufficient to describe the data for short contact times.;An eight lump model which takes into account feedstock composition (paraffins, naphthenes and aromatics) was also evaluated. The model predicted gasoline yields to within ;The information presented in this work should help furnish the existing gap of kinetic data for short contact time riser cracking. The Riser Simulator can be considered a valuable tool for determination of relevant kinetic data and could also be used for purposes of catalyst screening since it achieves a reaction regime which is more realistic for riser cracking than that achieved by the industry standard MAT unit.