(48f) Two- and Three-Column Compact Smb Processes for Ternary Separation

Over the last years there has been intensive research on the simulated moving bed (SMB) process and, as a result, several new cyclic operating schemes have emerged. These include, among others, the cyclic modulation of internal flow rates [1] and asynchronous port switch [2]. These new schemes give rise to highly efficient setups, making it possible, for example, to operate an SMB unit with less than four columns.

The SMB process was originally designed for binary separation, although several alternatives have been suggested to achieve a ternary separation using SMB technology, such as tandem [3] or parallel [4] SMB schemes, and the JO process [5], among others.

In this work, SMB units with only two and three columns are used to achieve a ternary separation. The productivity and solvent requirement for each combination of process are optimized numerically based on a detailed column model. The dynamic optimization problem is formulated using a full-discretization approach [6,7] and solved using an efficient interior-point solver [8]. From the optimization results, the most favorable process for a given separation problem can be selected. Optimized configurations for several schemes are validated experimentally for the ternary separation of nucleosides by reversed phase.

References [1] E. Kloppenburg, E.D. Gilles, A new concept for operating simulated moving-bed processes, Chem. Eng. Tech. 22(1999) 813. [2] O. Ludemann-Hombourger, R.M. Nicoud, M. Bailly, Separation Science and Technology 35(2000) 1829. [3] Y. Xie, S.-Y. Mun, J.-H. Kim, N.-H.L. Wang, Standing wave design and experimental validation of tandem simulated moving bed process for insulin purification, Biotech. Prog. 18 (2002) 1332. [4] P.C. Wankat, Simulated moving bed cascades for ternary separations, Ind. Eng. Chem. Res. 40 (2001) 6185. [5] T. Masuada, T. Sonobe, F. Matsuda, M. Horie, Process for the fractional separation of multicomponent fluid mixture, US Pat. 5 198 120 (1993). [6] J.M.M. Araújo, R.C.R. Rodrigues, J.P.B. Mota, Use of single-column models for efficient computation of the periodic state of a simulated moving bed process, Ind. Eng. Chem. Res. 45 (2006) 5314. [7] J.M.M. Araújo, R.C.R. Rodrigues, J.P.B. Mota, Optimal design and operation of a certain class of asynchronous simulated moving bed processes, J. Chromatogr. A (2006) in press. [8] Y. Kawajiri, L.T. Biegler, Optimization strategies for simulated moving bed and powerfeed processes, AIChE J. 52 (2006) 1343.