Identifiability of the glyceride transesterification kinetics via alkaline catalysis

Abstract This study addresses the glyceride transesterification (TE) kinetics, a crucial step in bio-diesel production from vegetable oils. To overcome common limitations of the existing kinetic models, a n th order reversible model with a broader domain of application is fitted to experimental data gathered from different authors. We consider the glyceride TE employing sodium methoxide (NaOCH 3 ), and use a general four-step model building approach, including (i) structural identifiability analysis; (ii) outlier detection using a robust M-estimator; (iii) parameter estimation (PE) and subsequent construction of the respective confidence intervals; and (iv) practical identifiability analysis. The results show that although the kinetic models with five (5P) and six (6P) parameters are structurally non-identifiable, the former (5P) can be shown to be practically identifiable and fit accurately the data, with an average relative deviation (ARD) of 6.5 %.