Search

The applicability of sequential centrifugal partition chromatography for continuous fractionation of multicomponent mixtures, represented here by a mixture of four parabens with very similar molecular structure, was studied. The fractionation of the quaternary feed mixture was regarded as a separation of a pseudo-binary mixture. The model-based approach was used to select the biphasic liquid system and the unit operating parameters. All desired fractions were recovered with purities >99%. The influence of the solute concentration on the density, viscosity and volume ratio of the phases as well as on the partitioning of the solutes between the two phases was investigated. According to these results, possibilities for increasing the throughput were proposed and validated experimentally. For example, butyl paraben with a purity ≥99% was continuously separated from the rest of the parabens in a 250 mL unit with a throughput of 3.24 g h−1 and a solvent consumption of 0.33 L g−1. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1659-1673, 2017 [ABSTRACT FROM AUTHOR]

Sequential centrifugal partition chromatography ( sCPC) is a novel cyclic liquid-liquid chromatographic process. Each cycle comprises two steps, which differ by the liquid phase used as a mobile phase (upper or lower phase) and its flow direction. The feed is continuously separated into two product streams, which are collected alternately. The process includes six (four flow rates and two-step durations) interconnected operating parameters. In this work, by imposing a complete separation of a binary feed mixture and using the assumption of instantaneous solutes partition equilibrium, a set of constraints on the sCPC unit operating parameters is derived. Using these constraints, a region of complete separation, composed of a set of combinations of the two-step times, can be defined for a preselected feed and mobile phase flow rates. The approach is validated by simulation of a binary mixture separation in a sCPC using the cell model. © 2012 American Institute of Chemical Engineers AIChE J, 59: 241-249, 2013 [ABSTRACT FROM AUTHOR]

The article describes a procedure for separating chiral mixtures in real simulated moving bed (SMB) technology and presents a new flexible unit, the FlexSMB-LSRE. An extended SMB separation methodology was applied which considers different unit design particularities and a measures to compensate either dead volumes switching time asymmetries or delay in order to be able to separate a racemic mixture of guaifenesin with product purities higher than 98% and productivity of 23 g enantiomer/dm³CPS day in the lab-scale.

One of the first applications of Simulated Moving Bed (SMB) technology was in p-xylene recovery from mixed xylenes. The three main industrial processes for p-xylene separation from mixed xylenes based on SMB technology are: UOP's Parex, IFP's Eluxyl, and Toray's Aromax. These units operate in liquid phase (T = 180°C and P = 9 bar), achieving high recovery of almost pure p-xylene with high on-stream efficiency and extended adsorbent life. In this work, the industrial scale SMB process is investigated from modeling, simulation, and optimization points of view, using experimentally measured xylene adsorption equilibrium and kinetics data on ion exchanged faujasite zeolite. The aim is to develop tools for training of SMB unit operators and choice of the best operating conditions. Useful studies for better understanding of the influence of the operating parameters, adsorbent packing, and separation requirements on unit productivity are presented. SMB unit revamping strategies and operative actions are proposed. The practical application of "separation volume" methodology in the selection of optimum operating conditions that lead to maximum p-xylene productivity with minimal desorbent consumption is described. [ABSTRACT FROM AUTHOR]