A THEORETICAL APPROACH TO THE ANALYSIS OF PI-CONTROLLED CSTRS WITH NOISE

In this paper an analysis of the effects on the steady-state operation of PI-controlled CSTRs induced by noise in the temperature measuremen t is discussed, both numerically and theoretically. The theoretical ap proach was carried out in a simplified way, by solving the Fokker-Plan ck equation of the linearisation of the stochastic model of the reacto r at the stable steady state. The effectiveness of this simplification is discussed: the linearisation is a valid approximation for controll ed CSTRs, apart from a narrow region near the Hopf bifurcation. Linear isation has subsequently been applied for the identification of reliab le safety criteria for the choice of the control gains, with the advan tage of a major saving of time. Stochastic resonance is also analysed. (C) 1998 Elsevier Science Ltd. All rights reserved.