Production of Soy Isolates by Ultrafiltration: Process Engineering Characteristics of the Hollow Fiber System

The effect of various performance parameters on flux during the hollow fiber ultrafiltration of defatted soy flour extracts was studied. Flux was significantly affected by pressure up to the limits of the unit. Higher temperatures also increased flux. However, flow rate had practically no effect. Also, no hysteresis effects were observed upon lowering the pressure from the highest to lowest values. The data indicated that concentration polarization or mass transfer was not rate-controlling and flux behavior could be modelled by momentum transfer considerations. A modified power law version of the Poiseuille equation, J= A (▵PT)n, best fit the data, where J is the flux, ▵PT is the transmembrane pressure and A and n are constants characteristic of a particular membrane-feed combination. A and n decreased with increasing solids in the feed, and A increased while n decreased with increasing temperature.