On POD reduced models of tubular reactor with oscillatory behaviour

The distributed model of a tubular reactor with recycle is reduced by approximating it first with a Continuous Stirred Tank Reactor (CSTR) cascade. Proper orthogonal decomposition (POD) with Galerkin projection is introduced to study oscillatory regimes. The dynamics of the resulting models is studied via numerical simulation, and solutions in the form of time series and phase plot diagrams are compared to those obtained for the original CSTR cascade model. Different methods to choose the minimum number of basis functions are compared and discussed. Solution diagrams built with POD models are compared with those from CSTR cascade, as a function of the Damkoehler number. Features and limitations of POD models are discussed for different snapshot sampling policies and for different values of the Peclet number. Qualitative performance increases and quantitative performance decreases as samples from steady states are considered along with periodic solution samples. Performance becomes worse as the Peclet number increases.