Dynamic modelling of a gas phase catalytic fixed bed reactor—III: Identification using binary pulse sequence test signals

Abstract

The dynamics of a gas phase catalytic reactor is identified experimentally using broad bandwidth Walsh-Hadamard sequences as test signals. The binary test signals are designed from Walsh functions as they appear in Hadamard matrices. Each element of the matrix is multiplied with a fundamental signal with zero mean. The input and output time series are Fourier analysed to give local frequency responses. The reliabilities of the estimated gain and phase angels are evaluated and provide a useful guide for experimental design and interpretation. Results from a Walsh-Hadamard sequence are compared to results from a square wave signal and found to give similar accuracy. Good agreement between experimental values and theoretical predictions is obtained. The test signal period should be at least three times the thermal residence time or generally the dominating time delay.