FREQUENCY-RESPONSE OF AN ADSORBER WITH MODULATION OF THE INLET MOLAR FLOW-RATE - II - A CONTINUOUS-FLOW ADSORBER

A new method of frequency response analysis of an adsorber, with modul ation of the adsorbate molar supply instead of traditional modulation of the reservoir volume, is presented. A continuous mode of operation is considered, for three different types of mass transfer mechanisms i nside the particle: Langmuir kinetics, micro-pore diffusion and parall el pore and surface diffusion. Frequency response to sinusoidal and sq uare wave modes of perturbation are investigated. In the case of squar e-wave forcing function, the system pressure response contains higher harmonics, which makes the study of fast dynamics more feasible by usi ng relatively low frequencies of the input perturbations and analyzing the higher harmonics in the output signal. Simulation results show th at the in-phase characteristic function of the continuous-flow adsorbe r is the same as that of a batch or a semi-batch one, while the out-of -phase characteristic function differs substantially, showing a minimu m and a maximum, or no extrema at all, depending on the overflow. The conditions for extrema existence are discussed. Parameter estimation f rom simulated FR with inlet flow-rate modulation is also presented. (C ) 1998 Elsevier Science Ltd. All rights reserved.