STANDING-WAVE ANALYSIS OF SMB CHROMATOGRAPHY - LINEAR-SYSTEMS

The concept of standing concentration waves is introduced to derive de sign equations for continuous moving bed (CMB) processes. For linear i sotherm systems simple equations are derived from the analysis to link product purity and recovery to zone lengths, bed movement velocity, f low rates, column capacity factors, and mass-transfer coefficients. On ce product purity, recovery and feed flow rate are specified for a giv en system, the zone flow rates and bed movement velocity that provide the highest throughput and the lowest solvent consumption can be deter mined from the solutions. In a given system, there is a trade-off betw een product purity and throughput If bed volume and product purities a re Feed, the longer the zone lengths, the higher the throughput. Simul ations based on a linear driving force model that considers axial disp ersion and lumped film and intraparticle diffusion are used to compare the column profiles and effluent histories of CMB and simulated movin g bed (SMB). A numerical algorithm is introduced to allow simulation o f both CMB and SMB operations using the same program. The comparison s hows that the design equations derived for CMB systems are applicable to SMB systems Finally, the standing wave solutions are used to analyz e an experimental SMB system from the literature (Ching et al, 1991). Simulations agree closely with the data and the predictions of the the oretical analysis.