OPTIMIZATION DIAGRAM FOR MEMBRANE SEPARATIONS

A novel methodology has been developed which enables optimization of m embrane separations. In multicomponent separation processes, sieving c oefficients for the individual solutes, defined as the ratio of the fi ltrate and feed concentrations, tend to reach optimum values under dif ferent process conditions. It is not possible to determine a priori th e pair of sieving coefficients which will give the best combination of product yield and purification for a given application. A purificatio n factor-yield diagram for such an optimization has been developed whi ch utilizes a family of curves representing two dimensionless numbers plotted on yield versus purification-factor coordinates. Analysis can be performed with knowledge of only three experimental variables: the filtrate flux and the two solute sieving coefficients. Complete optimi zation of membrane processes can be achieved by combining these variab les with membrane area, process time, and retentate-volume constraints . The methodology should be applicable to ultrafiltration, microfiltra tion, and high-performance tangential flow (selective) filtration proc esses.