Design and optimisation of a simulated moving bed unit: role of deviations from equilibrium theory

Biressi, Giovanni; Ludemann‐Hombourger, Olivier; Mazzotti, Marco; Nicoud, Roger‐Marc; Morbidelli, Massimo

doi:10.1016/s0021-9673(00)00191-6

Cited by 100 publications

(58 citation statements)

References 18 publications

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“…[18 -20,31 -37] Consequently, if mass transfer effects are important, the operating conditions obtained by the equilibrium theory design must be modified, i.e., the region for complete separation defined by the equilibrium approach is reduced under nonideal conditions. [18,19,22,23,35,36] As we will show in the present work, mass transfer resistance can modify the better SMB operating conditions, leading to significant differences in the performance parameters such as productivity and solvent consumption. As it was already noticed for linear systems, [22] the constraints for Sections 1 and 4 will also be changed and will no longer depend solely on equilibrium data.…”

Section: Design Of Smb Chiral Separationsmentioning

confidence: 76%

Design of SMB Chiral Separations Using the Concept of Separation Volume

Rodrigues

Pais

2005

Separation Science and Technology

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The article deals with chiral separation by simulated moving bed (SMB) chromatography. When mass transfer resistances are negligible, equilibrium theory provides explicit criteria for the choice of the SMB operating conditions. However, in the presence of mass transfer resistances, the SMB operating conditions should be evaluated through simulation. Using a package based on the analogy with the true moving bed operation, this work shows how mass transfer resistance can affect the conditions for enantiomers separation, as well as the critical values stated by equilibrium theory. The concept of separation volume is applied to show how the flow-rate constraints, in presence of mass transfer

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Section: Design Of Smb Chiral Separationsmentioning

confidence: 76%

Design of SMB Chiral Separations Using the Concept of Separation Volume

Rodrigues

Pais

2005

Separation Science and Technology

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“…The number of degrees of freedom in the design problem is, therefore seven: column length and diameter, switching time and the four section velocity ratios j γ . The algorithm to be applied is an extension of that developed by Biressi et al (2000). However, instead of using a model of equilibrium stages, we have used a detailed TMB steady-state model, as described in a previous publication , since this system (fructoseglucose on ion-exchange resin) involves considerable mass transfer resistance, which is adequately predicted with a rigorous model.…”

Section: Theory Underlying the Design Algorithmmentioning

confidence: 99%

“…According to the guidelines proposed by Biressi et al (2000), the following two assumptions are made: i A given SMB recycle flowrate (Q 1 ) is assumed and all other flowrates and column cross section are obtained based on that value. After the algorithm calculations are finished, a scale parameter Ω is calculated as the ratio between the desired feed flowrate and the theoretical feed flowrate, which is that obtained for the recycle flowrate assumed a priori.…”

Section: Theory Underlying the Design Algorithmmentioning

confidence: 99%

“…For a given bead diameter, optimum column length and mobile phase velocity are derived. Following a similar approach, other optimization strategies have been reported (Biressi et al, 2000;Ludemann-Hombourger et al, 2000), which basically elected the adsorbent productivity as an objective function to be maximized. The present work applies a strategy to find design construction parameters and operating conditions required to achieve a desired product purity to the case of fructose-glucose separation using exchange resins.…”

Section: Introductionmentioning

confidence: 99%

“…These parameters are then optimised by electing the adsorbent productivity as objective function. The algorithm used is based on the work of Biressi et al (2000); however, instead of using a staged equilibrium model, this work incorporates a detailed steady state process model proposed in a previous publication . The model is based on the equivalent representation of a true moving bed (TMB) due to the much lesser computational effort required in its solution as compared to dynamic SMB models.…”

Section: Introductionmentioning

confidence: 99%

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Design and optimization of new simulated moving bed plants

Azevedo

Rodrigues

2006

Braz. J. Chem. Eng.

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-The simulated moving bed (SMB) technology has attracted considerable attention for its efficiency as a chromatographic adsorptive separation. It has been increasingly applied to the separation of binary mixtures with low separation factors, namely to separate isomers. Although quite a vast amount of information has been published concerning the simulation and design of operating conditions of existing SMB plants, fewer works have addressed the question of design and optimisation of geometric parameters and operating conditions of a new adsorber, especially when mass transfer resistances are significant. The present work extends an algorithm developed elsewhere to design SMB equipment and optimize its operating conditions and applies it to the case of fructose-glucose separation using a cation-exchange resin as stationary phase in order to obtain nearly pure fructose in the extract and glucose in the raffinate. The constraints were set as 99% purity for both products. The objective function was chosen to be the adsorbent productivity. The algorithm attempted to find the minimum column lengths for increasing throughputs, which met the required purity constraint. Then, the best construction parameters and operating conditions were chosen as those for which the adsorbent productivity was maximum. The effects of the safety margins applied on the velocity ratios in sections 1 and 4 were examined and a heuristic rule for optimum eluent flowrate was derived. The effect of the purity requirements was also investigated. Finally, the calculated optimal operating points, in terms of flowrate ratios in SMB sections 2 and 3, were analysed in the frame of the equilibrium theory. Sound coherence was verified, which confirmed the accuracy and adequacy of the extended algorithm for the design and optimisation of a SMB adsorber with strong mass transfer effects.

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Adsorption, Liquid Separation

Gembicki¹,

Oroskar²,

Johnson³

2002

Kirk-Othmer Encyclopedia of Chemical Technology

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Nearly every chemical manufacturing operation requires the use of separation processes to recover and purify the desired product. Liquid‐phase adsorption has long been used for the removal of contaminants present at low concentrations in process streams such as in deodorization of water, decolorization of sugar, and ion exchange of fermentation broth. Liquid‐phase simulated moving bed (SMB) processes are being increasingly used for bulk separation of a whole range of molecules whose molecular properties are very similar. Examples are p ‐xylene from C 8 aromatics, normal paraffins from iso‐paraffins, fructose from glucose, and chiral molecules in the pharmaceutical industry. When it comes to the separation of close boiling molecules, SMB processes generally provide a better alternative to other conventional means of separation from both operating and capital costs point of view. This article reviews the application of liquid‐phase adsorption processes in the hydrocarbon, industrial chemicals, food, and pharmaceutical industry. Special emphasis is given to the class of processes referred to as SMB processes including fundamental SMB principles , and the general applicability and guidelines for SMB design. The paper also illustrates several examples of SMB applications in the petrochemical industry and its recent growth in the pharmaceutical and biotech industry.

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Design and optimisation of a simulated moving bed unit: role of deviations from equilibrium theory

Cited by 100 publications

References 18 publications

Design of SMB Chiral Separations Using the Concept of Separation Volume

Design of SMB Chiral Separations Using the Concept of Separation Volume

Design and optimization of new simulated moving bed plants

Adsorption, Liquid Separation

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