(196d) High- Purity and High-Yield Separations of Three Amino Acids In a Tandem SMB: Standing Wave Design and Column Dynamics
Batch chromatography is a major adsorptive separation method. It has been widely used for analytical applications. It is, however, less efficient for large scale production than simulated moving bed chromatography (SMB). SMB has not been widely used for the separation of mixtures with three or more components. A major barrier is the difficulty in SMB design, which involves specifying the length of each zone (the region between two ports), the flow rate in each zone, and the port velocity to achieve high product purity and high yield. Design by trial and error is costly and challenging. A second barrier is the lack of commercial SMB equipment for multi-component separations. We developed a novel design method based on the concept of standing concentration waves to overcome the first barrier. A difference between the port velocity and a wave velocity is used to focus a key concentration wave in each zone to control product purity, yield, and the split (distribution of the various components in the two products). When intrinsic adsorption and diffusion parameters are known, the required flow rates and port velocity can be calculated easily. This method reduces the optimization search space by five dimensions for a four-zone SMB. A simulation tool based on a detailed rate model was developed to verify the purity and yield targeted in the Standing Wave Design. We also developed tandem SMB equipment with versatile configurations to address the second barrier. In this study, the Standing Wave Design was used in developing a tandem SMB process (two loops in series) for recovering three amino acids with high purity and high yield from a ternary mixture. The design was first verified using the rate model simulations and then tested using data from the versatile SMB equipment. The results showed close agreement between the rate model predictions and the simulated concentration profiles and dynamic effluent histories. Dynamic concentration profiles are used to gain insight on the detailed mechanisms of ternary separation in the tandem SMB.