Strategia sperimentale per la progettazione ottimale di unità di ultrafiltrazione per il recupero di biopimeri alimentari da soluzioni molto viscose
Author(s)
Sebastiani, Ilio
Date Issued
March 14, 2008
Type
Doctoral Thesis
Abstract
This PhD thesis was directed to identify a comprehensive mathematical model of the
ultrafiltration (UF) recovery of a couple of target food biopolymers (i.e. sodium alginate
and pectin) from highly‐viscous model solutions using a laboratory‐scale plant,
appropriately assembled and equipped with a ceramic UF tubular module. As the
concentration of both solutes in the retentate (cBR) increased up to 7‐10 kg m‐3, the limiting
permeation flux (JP∞) decreased to values of 25‐40 dm3 m‐2 h‐1, that were quite
independent of the feed superficial velocity (vS). It was proved that the change in slope of
the plot JP∞‐vs.‐log(cBR) was due to the transition from turbulent to laminar flow regime.
By resorting to two dimensionless empirical regressions among the modified Sherwood,
Reynolds and Schmidt numbers, valid in the laminar or turbulent flow regime, it was
possible to achieve quite a satisfactory simulation of a few independent validation tests
performed in the batch mode in the laboratory‐scale plant, as well as to reconstruct the JP∞
values observed by other authors using commercial ceramic or polyethersulphone
tubular modules. Thus, use of such empirical regressions might be recommended as
design tools for further scaling‐up exercises of these UF processes, whereas the
experimental strategy here set up may be used to assess the basic parameters for
designing or optimising UF units.
Additional information
Dottorato di ricerca in Biotecnologia degli alimenti
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