Role of mass transfer coefficient with suction including property variations to predict limiting phenomena during ultrafiltration

Analytical expressions for limiting flux, limiting concentration at the mem brane surface, limiting operating pressure are developed for osmotic pressu re controlled cross flow ultrafiltration. Modified Sherwood number relation ships incorporating the effects of suction and variations of physical prope rties are used to estimate mass transfer coefficient in a rectangular geome try. The model is solved to predict the limiting flux of bovine serum album in and dextran data, obtained from the literature. A parametric study of li miting flux with different parameters (e.g., Reynolds number, feed concentr ation, real retention of the membrane, etc.) is also carried out. Further, the analysis is also carried out for a partially retentive membrane. Explic it quantification of limiting pressure would be of immense help for the des ign engineers from both operational and economic points of view. (C) 1999 E lsevier Science B.V. All rights reserved.