Selection of optimal sensor position in a tubular reactor using robust degree of observability criteria

Robust selection criteria for the optimal location for in-process concentra tion or temperature sensors along the length of a tubular reactor for the p artial oxidation of Benzene to Maleic Anhydride are developed. A model of t he reactor is constructed by rewriting the Pde's describing the mass and he at balances into a set of Ode's through the method of lines on a grid defin ed over the reactor length. The linearized model is described as a continuo us, time-invariant state-space model where the state is formed by temperatu re and concentration profiles on the grid points. The best sensor location for the reactor is found by specifying scalar measures on the observability Gramian integral from the linear least-squares state estimation problem. N ew robust criteria for a degree of observability are specified. The scores on these criteria are determined by the amount of signal received by a sens or for a specific system configuration. These new selection criteria are co mpared with known measures for degree of observability for the optimal sens or location problem from the literature. (C) 1999 Elsevier Science Ltd. All rights reserved.