Performance comparison of different pressure drop, hold-up and flooding point correlations for packed columns

Abstract

The hydraulic properties of pressure drop, hold-up and flooding point are of immense importance to describe the performance of random and structured packings. Therefore, accurate modelling of these performance parameters over the whole operating range has to be ensured. For this reason, many correlations have been developed by different institutions in the past (Billet and Schultes, 1991, 1999; Wolf, 2014; Engel, 1999; RBF (Rocha, Bravo, Fair), 1993, Delft-model (Olujić) 1997; Verschoof, 1999; Maćkowiak, 2003, Stichlmair, 1989). As these correlations are usually only reliable for validated packings, the purpose of this work is to evaluate these models based on the significant database of the Separation Research Program (SRP) at The University of Texas and the database of Montanuniversitaet Leoben (MUL). Combined, these databases include pressure drop, liquid hold-up and flooding point data for 50 different random and structured packings at different operating conditions. Furthermore, some pressure drop and flooding data obtained from the SRP 43cm diameter distillation column are also used.In this work, the predictions of the various correlations are compared and the application fields of the various models are revealed. In particular, the paper shows the operating ranges as well as packing types for which the models provide reliable predictions but also the weaknesses of the various correlations. Particularly, a modification of the Maćkowiak model is introduced which leads to a significantly improved modelling performance.