Separation Science and Technology, Vol.40, No.4, 791-809, 2005
Lysine adsorption on cation exchange resin. III. Multicolumn adsorption/desorption operation
A model previously developed to describe ion exchange equilibria, kinetics, and column dynamics of lysine adsorption on a strong acid cation exchanger is extended to simulate the cyclic adsorption/desorption of lysine in a multicolumn, simulated countercurrent system. The system simulated comprises an adsorption zone, a desorption zone, and two zones where unadsorbed feed components and excess desorbent are removed. Multiple columns are distributed among the four zones in different simulated countercurrent schemes, including a scheme that allows recycling of excess desorbent and another where the lysine recovery yield is enhanced at low flow rates by lowering the pH in the last column of the adsorption zone. Model predictions are validated by comparison with experimental results obtained in an eight-column bench scale apparatus and a parametric study is conducted with the model to determine the effects of critical design variables.