Rui P.V. Faria

Instrumental aspects of Simulated Moving Bed chromatography.

The Simulated Moving Bed (SMB) is one of the greatest illustrations of the potential of continuous multicolumn counter-current chromatographic processes. Although it was initially developed for the purification of petrochemicals, the advances that this technology has experienced during more than 50 years of existence were at the basis of its successful expansion into the food and pharmaceuticals industries. In this context, the present work provides an overview of the evolution of SMB focused on the most relevant instrumental aspects related with this technology. For that purpose, the details of the design and construction of this equipment will be reviewed, with special attention to the valves design. Due to its increasing interest, the technical requirements imposed by unconventional operating modes will be addressed together with the design adaptations that allow the operation of SMB units with compressible fluids and the implementation of Hybrid-SMB processes. Finally, as SMB technology has been unable to meet all the process specifications within the growing biopharmaceuticals industry, the development of alternative multicolumn counter-current units has intensified over the last few years. Hence, examples of the design and application of these new units will be provided.

Selection of a stationary phase for the chromatographic separation of organic acids obtained from bioglycerol oxidation

A screening study of the chromatographic separation of Glyceric Acid (GCA) and Tartronic Acid (TTA) was performed using three different polystyrene-divinylbenzene ion-exchange resins in hydrogen form (Dowex® 50WX-8, Dowex® 50WX-4, Dowex® 50WX-2). The experiments were described by the axial dispersion flow model with the LDF approximation incorporated into the software gPROMS. From the three investigated adsorbents differing by the crosslinking, Dowex® 50WX-2 has presented the higher adsorption capacity, as well as the highest bed efficiency expressed by the number of theoretical plates. The adsorption equilibrium constants were determined from single breakthrough experiments, and a very good agreement between experimental and simulated data was achieved for both single components and binary mixtures. Therefore, the fundamental data determined within this work represents a key contribution to the design of continuous chromatographic processes for the purification of GCA and TTA.

Separation of tartronic and glyceric acids by simulated moving bed chromatography

The SMB unit developed by the Laboratory of Separation and Reaction Engineering (FlexSMB-LSRE®) was used to perform tartronic acid (TTA) and glyceric acid (GCA) separation and to validate the mathematical model in order to determine the optimum operating parameters of an industrial unit. The purity of the raffinate and extract streams in the experiments performed were 80% and 100%, respectively. The TTA and GCA productivities were 79 and 115u202fkg per liter of adsorbent per day, respectively and only 0.50 cubic meters of desorbent were required per kilogram of products. Under the optimum operating conditions, which were determined through an extensive simulation study based on the mathematical model developed to predict the performance of a real SMB unit, it was possible to achieve a productivity of 86u202fkg of TTA and 176u202fkg of GCA per cubic meter of adsorbent per day (considering the typical commercial purity value of 97% for both compounds) with an eluent consumption of 0.30 cubic meters per kilogram of products.

Chromatographic studies of n-Propyl Propionate: Adsorption equilibrium, modelling and uncertainties determination

Abstract The n-Propyl Propionate (ProPro) is a compound that has several possible industrial applications. However, the current production route of this component presents several problems, such as the downstream purification. In this way, chromatographic separation could be an alternative solution to the downstream purification. In this work experimental studies of the ProPro reaction system separation in a chromatographic fixed bed unit packed with Amberlyst 46 were performed. The adsorption equilibrium isotherms and the corresponding Langmuir model parameters were determined. A phenomenological model to represent the process was developed and validated through the experimental data. Meanwhile, it is proposed the characterization of the uncertainties of all steps and its extension to the model prediction, which allowed to estimate the model parameters with a reduced number of experiments, when compared with other reports in the literature; nevertheless, the final results lead to a statistically more reliable model.