The effect of turbulence promoter on cross-flow microfiltration of skim milk

The effect of turbulence promotion on cross-flow microfiltration of skim milk was studied experimentally. The use of Kenics static mixer as turbulence promoter in inorganic (Membralox™) membranes with pore sizes 50, 100 and 200 nm provided a significant permeate flux improvement. In experiments at the same Reynolds number, the flux improvements of more than 500% were achieved for Re numbers in the range 3000–10 000. The increase of power consumption for fluid flow due to the insertion of turbulence promoter was also discussed. The effect of turbulence promoter on microfiltration performance was checked at the same hydraulic dissipated power. The flux improvements of more than 300% were achieved for hydraulic dissipated power in the range from 0.13 to 0.95 W indicating that using the turbulence promoter is more energy efficient than operation without the turbulence promoter. The fouling resistance analysis approved that resistance of the surface micellar layer dominates the overall fouling resistance. The use of turbulence promoter caused a large scouring of the membrane surface provided significant reduction of reversible fouling. Also, when the turbulence promoter was used, the membrane cleaning efficiency was improved compared with experiment without the promoter.