Standing-Wave Design of a Simulated Moving Bed under a Pressure Limit for Enantioseparation of Phenylpropanolamine

An improved standing-wave design method is developed for nonlinear simulated moving bed (SMB) systems with significant mass-transfer effects and an operating pressure limit. The design method was verified with rate model simulations and then tested for enantioseparation of phenylpropanolamine. High purity (>99%) and high yield (>99%) were achieved experimentally using a SMB with a pressure limit of 350 psi. The verified design method was used to find the optimal column length that gives the maximum throughput per bed volume. For a given particle size and a pressure limit, the optimal column length falls on the boundary between the mass-transfer-limiting region and the pressure-limiting region. If a characteristic dispersion velocity is more than 0.2% of an interstitial velocity, mass-transfer effects must be considered in the design in order to guarantee 99% purity and yield.