Control of a fluid catalytic cracking unit based on proportional-integral reduced order observers

The fluid catalytic cracking (FCC) unit is one of the most complex interact ive processes in the refining industry, and is difficult to operate and con trol. This work deals with the regulative control law design for stabilizat ion of the reactor and regenerator temperatures, considering that the kinet ics terms are poorly known. The proposed control law makes use of on-line e stimates of the input/output modeling errors, obtained from a proportional- integral reduced order observer. The structure of the proposed controller i s similar to a proportional-double integral compensator (PI2) such that a n ew parameterization of the controllers gains is given in terms of the close d-loop and estimation time constants. The performance of the control scheme proposed here is analyzed via numerical simulations. (C) 1999 Elsevier Sci ence S.A. All rights reserved.