In order to develop and model an efficient continuous separation process based on foam fractionation, bovine serum albumin (BSA) solution was experimentally investigated for the effect of operation parameters (feed concentration, foam sampling height, and superficial gas velocity) on separation ratio (SR). Then, an engineering approach was taken to describe this separation scheme, resulting in a design factor (xi) which is strongly related to foam structure. A fairly good correlation between this design factor and the operating parameters, based on the nonlinear regression analysis with experimental data, was obtained.