On the chaotic behavior of externally forced industrial fluid catalytic cracking units

A good insight into the effect of external disturbances on industrial units can be obtained by the investigation of the effect of periodic forcing. Therefore, the effect of periodic forcing of the air feed temperature on the bifurcation behavior, gasoline yield, and amplitude modulation of a type IV industrial fluid catalytic cracking (FCC) unit is investigated. The investigation concentrates on a case in which the autonomous system shows bistability between a high temperature static attractor and a periodic attractor (the emphasis being on the periodic attractor). The center of forcing considered in this case is moderately removed from the homoclinic termination point of the autonomous periodic branch. The one-parameter stroboscopic Poincaré bifurcation diagram reveals the richness of the dynamic behavior of the forced system (periodicity, aperiodicity, bifurcations, inverse bifurcations, intermittency, boundary crisis, shrinking size torus and chaos). The investigation reveals that period doubling, type 1 intermittency and boundary crisis are the dominant routes to chaos. Lyapunov exponents are computed to distinguish between chaotic and non-chaotic complex attractors. The average gasoline yield obtained with the attractor resulting from the forcing of the autonomous static attractor increases slightly with increase in forcing amplitude. All chaotic attractors resulting from the forcing of the autonomous periodic attractor give slightly higher gasoline yields than their autonomous counterparts.