Question

Time Required for Ultrafiltration A protein so- lution at a concentration of 0.5 g/liter and volume of 1000 liters must be concentrated on a crossflow ul- trafilter to a concentration of 10 g/liter. The ultrafil- ter has an area of 100 m² and operates at 5°C with an inlet feed pressure of 16.0 bar, outlet feed pres- sure of 14.0 bar, and back pressure on the permeate of 1.4 bar. The protein has a molecular weight of 20,000 Da and will not pass through the ultrafiltra- tion membranes. The feed has a viscosity of 1.2 cp. The membrane resistance (Rm) of the ultrafilter has been determined to be 2 x 103 cm-1. The Reynolds number for flow within the ultrafilter is large enough to render concentration polarization negligible. Determine the time required to perform the ultrafiltration.

Answer 1

Darcy's Law can be used to determine the working of ultrafiltration membrane, here the assumption is that the flux from the membrane remains constant throughout the process, The inlet feed pressure is used to determine TMP(transmembrane pressure=difference between feed pressure and permeate pressure).