Home About us Contact
|
Home About us Contact | ||
|
|
||
Simulated Moving (simulated + moving)
Selected AbstractsSeparation of chiral mixtures in real SMB units: The FlexSMB-LSRE®AICHE JOURNAL, Issue 1 2010Pedro Sá Gomes Abstract In this work, a procedure for the separation of a racemic mixture of guaifenesin onto a chiral stationary phase (Chiralpak AD), by means of Simulated Moving Bed (SMB) technology, is presented in four major steps: (1) search for the suitable stationary and mobile phases; (2) determination of sorption parameters and validation by frontal analysis; (3) modeling and design of the SMB unit; and (4) operation and demonstration. A major emphasis is given to the common deviations that "real" SMB units present when compared with the theoretical apparatus (due to tubing and equipment dead volumes, switching time asymmetries and delays, pumps flow rates variations). These deviations are analyzed before and after the design and construction of the FlexSMB-LSRE® unit, a new flexible unit, hereby presented. A detailed model that takes into account tubing and equipment dead volumes, as well as switching time asymmetries and delay, was used to study and compare different dead volumes design and compensating strategies. It is shown that all these approaches can be converged into a switching time compensating strategy. This approach served to predict the experimental operating conditions and run a classical SMB experiment, which afterwards was compared with the simulated profiles obtained for the FlexSMB-LSRE® unit. The result of the separation was guaifenesin enantiomers with purities above 98% and a productivity value of 23 genantiomer/(dm3 CSP day). © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Design of Simulated Moving Bed Plants for Reduced PuritiesCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2010M. Fütterer Abstract Simulated moving bed (SMB) chromatography is an established separation technology, where chromatographic columns are interconnected to a ring. The feeding and drains are switched over cyclically, such that a continuous separation becomes possible. For a faultless operation, the volumetric flow rates and switching time must be carefully adjusted. Therefore, it is desirable to calculate these values in dependence of the model parameters exactly. In this contribution, a new method is introduced to compute operating points for dispersion-free SMB plants and to predict the associated time trajectories of the concentrations at the drains in cyclic steady state for user-specified purities and degree of robustness. Simulation results are presented to show the potential of this new method. [source] Design of Simulated Moving Bed Plants by Using Noncompetitive Langmuir IsothermsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 10 2009M. Fütterer Abstract The simulated moving bed process is increasingly used for the separation of binary mixtures. To ensure proper operation, the volumetric flow rates and the time interval must be exactly adjusted. This study presents a general method for determining the control variables for a dispersion-free SMB process. For noncompetitive Langmuir isotherms, explicit equations are derived for the case of complete separation. The proposed method allows both a good estimation of the time trajectories of the concentrations at the drains and the design of new applications for optimization and control of SMB plants. [source] New Developments in Simulated Moving Bed ChromatographyCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2008A. Seidel-Morgenstern Abstract Chromatographic separation processes are widely used to isolate and purify value added products. Most frequently, such separation processes are performed exploiting the principles of injecting samples of the feed mixture in a repetitive periodic manner and collecting the target products batchwise. In the early 1960s, an alternative operation principle based on using several columns connected in series and exploiting a continuous countercurrent movement between the mobile and stationary phases initiated significant improvements in performing specific separation processes in the petrochemical and sugar industries. In the last decade, the so-called simulated moving bed (SMB) chromatography has rapidly entered the pharmaceutical industry. In particular enantioseparations using chiral stationary phases have become a strong driving force to develop more sophisticated concepts of continuous chromatography. Currently, the growing interest in efficient methods for the downstream processing of biomolecules enhances interest in SMB processes. This paper gives a brief overview of the new suggestions and trends. [source] Design of Simulated Moving Bed Plants for Reduced PuritiesCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2010M. Fütterer Abstract Simulated moving bed (SMB) chromatography is an established separation technology, where chromatographic columns are interconnected to a ring. The feeding and drains are switched over cyclically, such that a continuous separation becomes possible. For a faultless operation, the volumetric flow rates and switching time must be carefully adjusted. Therefore, it is desirable to calculate these values in dependence of the model parameters exactly. In this contribution, a new method is introduced to compute operating points for dispersion-free SMB plants and to predict the associated time trajectories of the concentrations at the drains in cyclic steady state for user-specified purities and degree of robustness. Simulation results are presented to show the potential of this new method. [source] SMB chromatography design using profile advancement factors, miniplant data, and rate-based process simulationAICHE JOURNAL, Issue 11 2009Shawn D. Feist Abstract This article describes a systematic miniplant-based approach to rapid development of simulated moving bed (SMB) chromatography applications. The methodology involves analysis of single-column pulse tests to screen adsorbents and operating conditions and to determine initial values of profile advancement factors used to specify flow rates for an initial SMB miniplant experiment. A lumped-parameter linear driving force rate-based model is developed by fitting process data from a single miniplant run. The data are fit in a two-step procedure involving initial determination of effective adsorption isotherm constants as best-fit parameters with subsequent adjustment of calculated mass transfer coefficients to refine the data fit. The resulting simulation is used to guide further miniplant work and minimize experimental effort. The methodology is illustrated with miniplant data for a binary protein separation showing excellent agreement between model results and process data generated over a wide range of operating conditions. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Mass-transfer effects during separation of proteins in SMB by size exclusionAICHE JOURNAL, Issue 5 2003Joukje Houwing The chromatographic fractionation of proteins by size-exclusion chromatography in a simulated moving bed (SMB) is studied. During experimental fractionation of a mixture of bovine serum albumin (BSA) and myoglobin on Sepharose Big Beads, mass-transfer effects are shown to limit the performance of the SMB. The internal profiles, as well as the extract and raffinate compositions, are described well by a steady-state equivalent true moving-bed (TMB) model that incorporates mass-transfer effects. The selection of the particle size in SMB is a trade-off between productivity and mass transfer. Based on the equivalent TMB model, the optimum particle size and configuration of the SMB can be selected, at which preset performance criteria (purity, recovery) are met at specified flow-rate ratios, total column length, and pressure drop. For the current feed and apparatus, an optimal particle size of approximately 145 ,m is calculated for achievement of purities and overall recoveries of 95%. [source] New Developments in Simulated Moving Bed ChromatographyCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2008A. Seidel-Morgenstern Abstract Chromatographic separation processes are widely used to isolate and purify value added products. Most frequently, such separation processes are performed exploiting the principles of injecting samples of the feed mixture in a repetitive periodic manner and collecting the target products batchwise. In the early 1960s, an alternative operation principle based on using several columns connected in series and exploiting a continuous countercurrent movement between the mobile and stationary phases initiated significant improvements in performing specific separation processes in the petrochemical and sugar industries. In the last decade, the so-called simulated moving bed (SMB) chromatography has rapidly entered the pharmaceutical industry. In particular enantioseparations using chiral stationary phases have become a strong driving force to develop more sophisticated concepts of continuous chromatography. Currently, the growing interest in efficient methods for the downstream processing of biomolecules enhances interest in SMB processes. This paper gives a brief overview of the new suggestions and trends. [source] | ||||||||||