PERFORMANCE OF COLLOCATION MODELS FOR SIMULATING TRANSIENT MULTISTAGESEPARATION UNITS

A systematic analysis has been developed to investigate the performanc e of reduced-order models for multistage separation units in transient simulations. In particular, we have analyzed the accuracy of these mo dels in reproducing some characteristic features of the dynamic behavi or of the original full-order model, i.e. the eigenvalue of smallest m odulus lambda(min) and the singular values obtained through open-loop singular value decomposition. It is found that as the relative volatil ity increases the maximum reduction factor allowed by a prescribed acc uracy decreases. The present analysis shows that, with the above limit ations on the value of the reduction factor, reduced-order models are able to capture the true dynamics of the corresponding full-order mode ls. Furthermore, the results indicate that the accuracy requirements i n transient simulations are more stringent than in steady-state simula tions, i.e. transient models require lower reduction factors for a giv en accuracy.