UNDERSTANDING OF RESONANCE PHENOMENA ON A CATALYST UNDER FORCED CONCENTRATION AND TEMPERATURE OSCILLATIONS

Resonance is an interesting phenomenon that may be observed for reacti ons on catalytic surfaces during periodic forcing of operating variabl es. Forcing of the variables for non-linear systems may result in subs tantially changed time averaged behaviour. These resonance phenomena h ave been observed experimentally by coincidence rather than by systema tic analysis. It is not clear for what type of reaction kinetics such behaviour may be expected and predictions are therefore impossible. Cl early, this forms a serious obstacle for any practical application. In this work we set out to analyse the nature of resonance behaviour in heterogeneously catalysed reactions. A Langmuir Hinshelwood microkinet ic model is analysed. It is demonstrated that for weakly non-linear fo rcing variables - as inlet concentrations - forcing leads to resonance phenomena in terms of the reaction rate only in case high total surfa ce occupancies exist in the steady state. In contrast, forcing of stro ngly non-linear variables - like temperature - may give rise to resona nce phenomena for both low and high surface occupancies. Necessary con ditions for resonance to occur are derived. The analysis of resonance phenomena is greatly simplified by the availability of explicit analyt ical expressions as can be derived from Carleman linearization. We wil l demonstrate the merits of Carleman linearization as compared to nume rical integration.