Enhancement of ultrafiltration of milk proteins by applying twisted tapes: A sensitivity analysis using a response surface methodology

Abstract

This paper presents intensification of the ultrafiltration of milk proteins by application of twisted tapes as turbulence promoters to minimize membrane fouling. The aim was to examine the influence of operating conditions and twisted tape dimensions on the alleviation of flux and the consumption of specific energy. A twisted tape was inserted in the ultrafiltration membrane (50 nm pore size) to alleviate turbulence and minimize fouling. The response surface methodology was used for the sensitivity analysis of the effects of operating conditions on the responses. The analysis showed that the linear effect of the aspect ratio of the twisted tape has a dominant significant effect on flux improvement. The linear effect of cross-flow rate has a positive dominant effect on the specific energy consumption. The linear effect of concentration and the mutual effect of aspect ratio and transmembrane pressure are statistically significant for both responses. By properly adjusting the operating conditions, a high flux improvement of 300 % could be reached with a specific energy consumption below 1.0 kW h m-3 using a twisted tape of an aspect ratio of 1.0 and imposing low transmembrane pressure.