1
|
Modeling of a Real-Life Industrial Reactor for Hydrogenation of Benzene Process. Catalysts 2021. [DOI: 10.3390/catal11040412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A dynamic model of the hydrogenation of benzene to cyclohexane reaction in a real-life industrial reactor is elaborated. Transformations of the model leading to satisfactory results are presented and discussed. Operating conditions accepted in the simulations are identical to those observed in the chemical plant. Under those conditions, some components of the reaction mixture vanish, and the diffusion coefficients of the components vary along the reactor (they are strongly concentration-dependent). We came up with a final reactor model predicting with reasonable accuracy the reaction mixture’s outlet composition and temperature profile throughout the process. Additionally, the model enables the anticipation of catalyst activity and the remaining deactivated catalyst lifetime. Conclusions concerning reactor operation conditions resulting from the simulations are presented as well. Since the model provides deep insight into the process of simulating, it allows us to make knowledge-based decisions. It should be pointed out that improvements in the process run, related to operating conditions, or catalyst application, or both on account of the high scale of the process and its expected growth, will remarkably influence both the profits and environmental protection.
Collapse
|
2
|
De Luca C, Felletti S, Macis M, Cabri W, Lievore G, Chenet T, Pasti L, Morbidelli M, Cavazzini A, Catani M, Ricci A. Modeling the nonlinear behavior of a bioactive peptide in reversed-phase gradient elution chromatography. J Chromatogr A 2019; 1616:460789. [PMID: 31874699 DOI: 10.1016/j.chroma.2019.460789] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 01/03/2023]
Abstract
The thermodynamic behavior of octreotide, a cyclic octapeptide with important pharmaceutical functions, has been simulated under reversed-phase gradient elution conditions. To this end, adsorption behavior was firstly investigated in isocratic conditions, under a variety of water/acetonitrile + 0.02% (v/v) trifluoroacetic acid (TFA) mixtures as mobile phase by using a Langmuir isotherm. Organic modifier was varied in the range between 23 and 28% (v/v). Adsorption isotherms were determined by means of the so-called Inverse Method (IM) with a minimum amount of peptide. The linear solvent strength (LSS) model was used to find the correlation between isotherm parameters and mobile phase composition. This study contributes to enlarge our knowledge on the chromatographic behavior under nonlinear gradient conditions of peptides. In particular, it focuses on a cyclic octapeptide.
Collapse
Affiliation(s)
- Chiara De Luca
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Simona Felletti
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Marco Macis
- Fresenius Kabi iPSUM, via San Leonardo 23, Villadose, Rovigo 45010, Italy
| | - Walter Cabri
- Fresenius Kabi iPSUM, via San Leonardo 23, Villadose, Rovigo 45010, Italy
| | - Giulio Lievore
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Tatiana Chenet
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Luisa Pasti
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Massimo Morbidelli
- Dept. of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Vladimir-Prelog-Weg 1, Zurich 8093, Switzerland
| | - Alberto Cavazzini
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy.
| | - Martina Catani
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy.
| | - Antonio Ricci
- Fresenius Kabi iPSUM, via San Leonardo 23, Villadose, Rovigo 45010, Italy
| |
Collapse
|
3
|
|
4
|
Investigation of retention mechanism of resorcinarene based cavitands by linear and nonlinear chromatography. J Chromatogr A 2016; 1456:152-61. [DOI: 10.1016/j.chroma.2016.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 04/01/2016] [Accepted: 06/01/2016] [Indexed: 11/20/2022]
|
5
|
Leśko M, Åsberg D, Enmark M, Samuelsson J, Fornstedt T, Kaczmarski K. Choice of Model for Estimation of Adsorption Isotherm Parameters in Gradient Elution Preparative Liquid Chromatography. Chromatographia 2015; 78:1293-1297. [PMID: 26435545 PMCID: PMC4580716 DOI: 10.1007/s10337-015-2949-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 07/14/2015] [Indexed: 11/24/2022]
Abstract
The inverse method is a numerical method for fast estimation of adsorption isotherm parameters directly from a few overloaded elution profiles and it was recently extended to adsorption isotherm acquisition in gradient elution conditions. However, the inverse method in gradient elution is cumbersome due to the complex adsorption isotherm models found in gradient elution. In this case, physicochemically correct adsorption models have very long calculation times. The aim of this study is to investigate the possibility of using a less complex adsorption isotherm model, with fewer adjustable parameters, but with preserved/acceptable predictive abilities. We found that equal or better agreement between experimental and predicted elution profiles could be achieved with less complex models. By being able to select a model with fewer adjustable parameters, the calculation times can be reduced by at least a factor of 10.
Collapse
Affiliation(s)
- Marek Leśko
- Department of Chemical and Process Engineering, Rzeszów University of Technology, 35 959 Rzeszów, Poland
| | - Dennis Åsberg
- Department of Engineering and Chemical Sciences, INTERACT, Karlstad University, 651 88 Karlstad, Sweden
| | - Martin Enmark
- Department of Engineering and Chemical Sciences, INTERACT, Karlstad University, 651 88 Karlstad, Sweden
| | - Jörgen Samuelsson
- Department of Engineering and Chemical Sciences, INTERACT, Karlstad University, 651 88 Karlstad, Sweden
| | - Torgny Fornstedt
- Department of Engineering and Chemical Sciences, INTERACT, Karlstad University, 651 88 Karlstad, Sweden
| | - Krzysztof Kaczmarski
- Department of Chemical and Process Engineering, Rzeszów University of Technology, 35 959 Rzeszów, Poland
| |
Collapse
|
6
|
Åsberg D, Leśko M, Enmark M, Samuelsson J, Kaczmarski K, Fornstedt T. Fast estimation of adsorption isotherm parameters in gradient elution preparative liquid chromatography II: The competitive case. J Chromatogr A 2013; 1314:70-6. [DOI: 10.1016/j.chroma.2013.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 08/29/2013] [Accepted: 09/01/2013] [Indexed: 11/12/2022]
|
7
|
Enmark M, Forssén P, Samuelsson J, Fornstedt T. Determination of adsorption isotherms in supercritical fluid chromatography. J Chromatogr A 2013; 1312:124-33. [DOI: 10.1016/j.chroma.2013.09.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 08/31/2013] [Accepted: 09/02/2013] [Indexed: 11/26/2022]
|
8
|
Åsberg D, Leśko M, Enmark M, Samuelsson J, Kaczmarski K, Fornstedt T. Fast estimation of adsorption isotherm parameters in gradient elution preparative liquid chromatography. I: The single component case. J Chromatogr A 2013; 1299:64-70. [DOI: 10.1016/j.chroma.2013.05.041] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 04/27/2013] [Accepted: 05/15/2013] [Indexed: 10/26/2022]
|
9
|
OuYang LF, Liu Q, Liang H, Shi Y, Shi J, Yin X. Simultaneous determination of two-component isotherm parameters and lumped mass transfer coefficients in RPLC with the 0-1 model-inverse method. J Sep Sci 2013; 36:645-57. [DOI: 10.1002/jssc.201200289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 10/29/2012] [Accepted: 11/01/2012] [Indexed: 11/12/2022]
Affiliation(s)
- Liang-fei OuYang
- Separation Science Institute; The Key Laboratory of Biomedical Information Engineering of Education Ministry; Xi'an Jiaotong University; Xi'an P. R. China
| | - Qian Liu
- Separation Science Institute; The Key Laboratory of Biomedical Information Engineering of Education Ministry; Xi'an Jiaotong University; Xi'an P. R. China
| | - Heng Liang
- Separation Science Institute; The Key Laboratory of Biomedical Information Engineering of Education Ministry; Xi'an Jiaotong University; Xi'an P. R. China
| | - Yuhua Shi
- Separation Science Institute; The Key Laboratory of Biomedical Information Engineering of Education Ministry; Xi'an Jiaotong University; Xi'an P. R. China
| | - Junwei Shi
- Separation Science Institute; The Key Laboratory of Biomedical Information Engineering of Education Ministry; Xi'an Jiaotong University; Xi'an P. R. China
| | - Xiaoguang Yin
- Separation Science Institute; The Key Laboratory of Biomedical Information Engineering of Education Ministry; Xi'an Jiaotong University; Xi'an P. R. China
| |
Collapse
|
10
|
Integration of scale-down experimentation and general rate modelling to predict manufacturing scale chromatographic separations. J Chromatogr A 2010; 1217:6917-26. [DOI: 10.1016/j.chroma.2010.08.063] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 08/23/2010] [Accepted: 08/25/2010] [Indexed: 11/21/2022]
|
11
|
Zhang Y, Rohani S, Ray AK. Numerical determination of competitive adsorption isotherm of mandelic acid enantiomers on cellulose-based chiral stationary phase. J Chromatogr A 2008; 1202:34-9. [DOI: 10.1016/j.chroma.2008.06.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Revised: 06/06/2008] [Accepted: 06/16/2008] [Indexed: 11/28/2022]
|
12
|
Kaczmarski K. Estimation of adsorption isotherm parameters with inverse method—Possible problems. J Chromatogr A 2007; 1176:57-68. [PMID: 17723232 DOI: 10.1016/j.chroma.2007.08.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 07/31/2007] [Accepted: 08/02/2007] [Indexed: 10/23/2022]
Abstract
In recent years the inverse method (IM) has been frequently applied to estimate of isotherm parameters. The IM has been used for adsorption process modeling for one, two and even three component chromatography. This method requires only a few injections with various sample concentrations, so the solute consumption and time requirements are very modest. The successful estimation of isotherm parameters with IM depends on applied chromatography column model and a numerical method used to solve the model. For HPLC column the classical equilibrium-dispersive (ED) model can be used. This model is solved frequently with very fast Rouchon finite difference method. However, the accuracy of computations with Rouchon method is decreasing with increase of the number of analyzed components. The aim of this work is the comparison of the results obtained with inverse method when ED model was solved with Rouchon or orthogonal collocation on finite element (OCFE) scheme. Assuming that solution of ED model with OCFE method can be regarded as real a solution, it was found that the Rouchon scheme may not give satisfactory results even for column with 10,000 theoretical plates for three component chromatography. Moreover, the optimal conditions for separation, calculated with Rouchon method, can be remarkably different from that obtained with the OCFE method. The next aim of this work is the presentation of Craig method application to estimation of model parameters with IM.
Collapse
Affiliation(s)
- Krzysztof Kaczmarski
- Department of Chemical and Process Engineering, Rzeszow University of Technology, ul. W. Pola 2, 35-959 Rzeszow, Poland.
| |
Collapse
|
13
|
|
14
|
|
15
|
Piatkowski W, Kramarz R, Poplewska I, Antos D. Deformation of gradient shape as a result of preferential adsorption of solvents in mixed mobile phases. J Chromatogr A 2006; 1127:187-99. [PMID: 16814799 DOI: 10.1016/j.chroma.2006.06.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2006] [Revised: 05/31/2006] [Accepted: 06/08/2006] [Indexed: 11/25/2022]
Abstract
Gradient elution has been studied in typical normal and reversed-phase systems. Deformations of gradient profiles have been evidenced as a result of preferential adsorption of modifiers of the mobile phase. This phenomenon was pronounced in the normal-phase system, for which gradient profiles deviated significantly from those programmed. This influenced the retention and shapes of band profiles of the eluting solute. Hence, in order to predict gradient propagation correctly the adsorption equilibrium of modifiers has been quantified. Moreover, at low modifier content, deformations of band profiles of the solute has been registered as a result of the competitive adsorption in the system solute-modifier. This effect has been predicted by a competitive adsorption model. For the reversed-phase systems the influence of the modifier adsorption on gradient propagation was insignificant for typical mobile phases investigated. Therefore, the work has been focused on gradient predictions in the normal-phase system.
Collapse
Affiliation(s)
- Wojciech Piatkowski
- Rzeszów University of Technology, Chemical Engineering and Process Control Department, al. Powstańców Warszawy 6, 35-959 Rzeszów, Poland
| | | | | | | |
Collapse
|
16
|
Zhang Y, Hidajat K, Ray AK. Determination of competitive adsorption isotherm parameters of pindolol enantiomers on alpha1-acid glycoprotein chiral stationary phase. J Chromatogr A 2006; 1131:176-84. [PMID: 16919658 DOI: 10.1016/j.chroma.2006.07.052] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Revised: 07/10/2006] [Accepted: 07/24/2006] [Indexed: 11/18/2022]
Abstract
In this paper, inverse method (IM) was used to determine the binary competitive adsorption isotherm of pindolol enantiomers by a least-square fitting of the proposed model to the experimentally measured elution curves of racemic pindolol. The isotherm parameters were determined by minimizing the least-square error using an adaptation of genetic algorithm, non-dominated sorting genetic algorithm with jumping genes (NSGA-II-JG). An equilibrium dispersive (ED) model combined with bi-Langmuir isotherm was used in predicting the elution profiles. The determined parameters show good agreement with the experimental profiles at various experimental conditions such as sample volume, concentration and flow rates of the racemic mixture. Robustness and validity of the isotherm parameters were also verified by frontal analyses at various step inputs. Results from both the pulse tests and the frontal analysis indicate that adsorption isotherm derived from the inverse method is quite reliable. This method requires relatively less number of experiments to be performed and therefore, lower experimental costs confirming that inverse method is an attractive alternative approach of experimental technique in determining the competitive adsorption isotherm for binary systems.
Collapse
Affiliation(s)
- Yan Zhang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore
| | | | | |
Collapse
|
17
|
|
18
|
Samuelsson J, Fornstedt T. Discovery of invisible extra fronts in single-component frontal analysis in liquid chromatography. J Chromatogr A 2006; 1114:53-61. [PMID: 16516900 DOI: 10.1016/j.chroma.2006.02.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2005] [Revised: 02/10/2006] [Accepted: 02/13/2006] [Indexed: 12/01/2022]
Abstract
Frontal analysis (FA) is often used in the "staircase mode", in which the solute concentration in the eluent increases stepwise. We demonstrate here in the single-component case, that all eluted breakthrough curves (fronts) for the second and subsequent steps consist solely of displaced plateau molecules. The newly introduced molecules (i.e., the introduced mass) instead elute later, in a breakthrough front hidden from detection, i.e., the mass front. These effects were studied using experimentally verified numerical calculations, the mass fronts being visualized using an enantiomer pair in an achiral separation system. Notably, the mass front displays no self-sharpening effects, even under strongly nonlinear conditions. Instead, the front is sigmoidal in shape.
Collapse
Affiliation(s)
- Jörgen Samuelsson
- Department of Physical and Analytical Chemistry, Uppsala University, BMC Box 577, SE-751 23 Uppsala, Sweden
| | | |
Collapse
|
19
|
Poplewska I, Piatkowski W, Antos D. Effect of temperature on competitive adsorption of the solute and the organic solvent in reversed-phase liquid chromatography. J Chromatogr A 2006; 1103:284-95. [PMID: 16343511 DOI: 10.1016/j.chroma.2005.11.038] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Revised: 11/11/2005] [Accepted: 11/14/2005] [Indexed: 11/18/2022]
Abstract
In analysis of the temperature effect on chromatographic separations the influence of the adsorption of organic solvent on the retention properties of solute is generally not taken into account. In fact, adsorption behavior of solutes is strongly affected by competitive adsorption of organic solvents, which is temperature dependent. In this work changes of adsorption equilibrium of an organic solvent as well as a solute with temperature have been analyzed. Data of the excess adsorption of methanol from aqueous solutions on octadecyl-bonded silica have been acquired at different temperature. Experiments have been performed over a relatively narrow temperature range corresponding to typical chromatographic conditions, i.e., 10-50 degrees C. The competitive adsorption equilibria of model solutes (i.e., two homologous compounds: cyclopentanone and cyclohexanone) have been measured at different temperature and composition of the mobile phase. Temperature alterations to the retention properties were found to result from combined effects of changes in adsorption behavior of the organic solvent and of the solute. The influence of temperature on the separation selectivity has been considered.
Collapse
Affiliation(s)
- Izabela Poplewska
- Department of Chemical and Process Engineering, Rzeszów University of Technology, 6 Powstańców Warszawy Avenue, 35-959 Rzeszów, Poland
| | | | | |
Collapse
|
20
|
Arnell R, Forssén P, Fornstedt T. Accurate and rapid estimation of adsorption isotherms in liquid chromatography using the inverse method on plateaus. J Chromatogr A 2005; 1099:167-74. [PMID: 16297923 DOI: 10.1016/j.chroma.2005.10.043] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 10/02/2005] [Accepted: 10/18/2005] [Indexed: 11/29/2022]
Abstract
The inverse method (IM) is an attractive approach for estimating adsorption isotherm parameters in liquid chromatography (LC), mainly due to its experimental simplicity and low sample consumption. This article presents a new experimental approach, the inverse method on plateaus (IMP), which uses elution profiles on concentration plateaus together with IM. This approach enabled us to obtain very accurate adsorption isotherms that agreed well with those estimated by means of frontal analysis over the entire concentration range under consideration. IMP is recommended when accurate adsorption isotherm estimates are required, and standard IM is insufficient.
Collapse
Affiliation(s)
- Robert Arnell
- Department for Surface Biotechnology, Uppsala University, BMC, Box 577, S-751 23 Uppsala, Sweden
| | | | | |
Collapse
|
21
|
Gedicke K, Tomusiak M, Antos D, Seidel-Morgenstern A. Analysis of applying different solvents for the mobile phase and for sample injection. J Chromatogr A 2005; 1092:142-8. [PMID: 16188569 DOI: 10.1016/j.chroma.2005.02.059] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Revised: 02/07/2005] [Accepted: 02/16/2005] [Indexed: 11/28/2022]
Abstract
Overloading a chromatographic column with a compound possessing low solubility in the mobile phase has been investigated. In order to increase the concentration of injection a strong solvent for dissolving the feed was used. The injection of such concentrated samples brings the risk of triggering undesired crystallisation processes. A model system has been investigated with ethanol-water as the mobile phase and DL-threonine as the sample dissolved in pure water. Under extreme overloaded conditions band splitting was observed. Measurements of the adsorption isotherms and systematic solubility studies were carried out. For the process analysis a simplified mathematical model was applied. The simulations of the band profiles were compared with the experimental data.
Collapse
Affiliation(s)
- Knut Gedicke
- Chair of Chemical Process Engineering, Otto-von-Guericke-University, 39106 Magdeburg, Germany
| | | | | | | |
Collapse
|
22
|
Piatkowski W, Petrushka I, Antos D. Adsorbed solution model for prediction of normal-phase chromatography process with varying composition of the mobile phase. J Chromatogr A 2005; 1092:65-75. [PMID: 16188561 DOI: 10.1016/j.chroma.2005.08.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 07/24/2005] [Accepted: 08/08/2005] [Indexed: 10/25/2022]
Abstract
The adsorbed solution model has been used to predict competitive adsorption equilibria of the solute and the active component of mobile phase in a normal-phase liquid chromatography system. The inputs to the calculations were the single adsorption isotherms accounting for energetic heterogeneity of the adsorbent surface and non-ideality of the mobile phase solution. The competitive adsorption model has been coupled with a model of the column dynamics and used for simulating of chromatography process at different mobile phase composition. The predictions have been verified by comparing the simulated and experimental chromatograms. The model allowed quantitative prediction of chromatography process on the basis of the pure-species adsorption isotherms.
Collapse
Affiliation(s)
- Wojciech Piatkowski
- Rzeszow University of Technology, Chemical Engineering and Process Control Department, al. Powstańców Warszawy 6, 35-959 Rzeszów, Poland
| | | | | |
Collapse
|
23
|
|
24
|
Ziomek G, Kaspereit M, Jezowski J, Seidel-Morgenstern A, Antos D. Effect of mobile phase composition on the SMB processes efficiency. J Chromatogr A 2005; 1070:111-24. [PMID: 15861794 DOI: 10.1016/j.chroma.2005.02.080] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The solvent composition was adjusted in a theoretical study in order to maximize the efficiency of a simulated moving bed (SMB) process. The isocratic realization of the process as well as the solvent gradient mode were considered. The solvent composition and the flow rates were used as decision variables in a random search optimization algorithm known to be a reliable tool for nonlinear programming problems. The results of the optimization indicate that the optimal composition of the mobile phase depends strongly on the feed concentration. The asymmetry of the internal concentration profiles, which has a negative effect on the separation efficiency, can be partly damped by an increase of the solvent strength. In the cases studied the optimal solvent strength determined for concentrated feed streams is higher than that for diluted ones. Moreover, the optimum is strongly influenced by the value of the selectivity factor and its dependency on the mobile phase composition. Different results were obtained for cases, in which the separation factor increases with increasing the modifier concentration, than for cases, in which the separation factor decreases with increasing the modifier concentration. A similar analysis was performed for a solvent gradient SMB process, in which different solvents are used at the two inlet ports: a weak solvent in the feed stream and a strong solvent in the desorbent stream. Again the optimal mobile phase composition was strongly affected by the type of the isotherms and their non-linearity. The potential of a gradient SMB process in terms of increasing the productivity and reducing the eluent consumption is exemplified.
Collapse
Affiliation(s)
- G Ziomek
- Max-Planck-Institut für Dynamik Komplexer Technischer Systeme, D-39120 Magdeburg, Germany
| | | | | | | | | |
Collapse
|
25
|
Effect of adsorption of organic solvents on the band profiles in reversed-phase non-linear chromatography. Chem Eng Sci 2005. [DOI: 10.1016/j.ces.2004.10.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
26
|
Shan Y, Seidel-Morgenstern A. Analysis of the isolation of a target component using multicomponent isocratic preparative elution chromatography. J Chromatogr A 2005; 1041:53-62. [PMID: 15281254 DOI: 10.1016/j.chroma.2004.04.061] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The separation of a certain target component from a multicomponent mixture using isocratic preparative elution chromatography was studied theoretically. In particular, the important and most complicated case was considered that the target component does not elute in the first or last position. To specify the productivity of collecting this component different options are suggested to identify suitable times for fractionation. Using a conventional Craig model, capable to quantify chromatographic processes, the impact of several essential parameters (e.g. threshold concentration, desired purity, injection volume, separation factor between neighboring components, composition of the mixture) is evaluated for a ternary system based on parametric calculations. The paper provides simple tools to evaluate and optimize the productivity and other objective functions relevant in multicomponent preparative chromatography.
Collapse
Affiliation(s)
- Yichu Shan
- Max-Planck-Institut für Dynamik Komplexer Technischer Systeme, Sandtorstrasse 1, D-39106 Magdeburg, Germany
| | | |
Collapse
|
27
|
Cavazzini A, Felinger A, Guiochon G. Comparison between adsorption isotherm determination techniques and overloaded band profiles on four batches of monolithic columns. J Chromatogr A 2003; 1012:139-49. [PMID: 14521310 DOI: 10.1016/s0021-9673(03)01185-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The adsorption isotherms of 4-tert.-butyl phenol were measured on four different monolithic columns, using three different techniques, classical frontal analysis (FA), the perturbation on a plateau method (PP) and the recently introduced numerical procedure known as the inverse numerical method (IN). This last approach requires only the recording of a few overloaded profiles and has the potential advantage of affording a dramatic decrease of the amounts of compounds, solvent, and time needed to determine accurate estimates of the coefficients of the isotherm. The reproducibility of the adsorption data measured on the four columns is discussed with reference to the specific techniques used for obtaining these data and to the most suitable equation used for modeling them. The data obtained for the different columns were highly consistent. The inverse numerical approach was confirmed to provide a powerful, accurate, and economic method for measuring single component adsorption data.
Collapse
Affiliation(s)
- Alberto Cavazzini
- Department of Chemistry, University of Tennessee, 552 Buehler Hall, Knoxville, TN 37996-1600, USA
| | | | | |
Collapse
|
28
|
Antos D, Kaczmarski K, Wojciech P, Seidel-Morgenstern A. Concentration dependence of lumped mass transfer coefficients linear versus non-linear chromatography and isocratic versus gradient operation. J Chromatogr A 2003; 1006:61-76. [PMID: 12938876 DOI: 10.1016/s0021-9673(03)00948-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The general rate model provides a reliable platform to predict elution bands in both linear and non-linear chromatography provided the required equilibrium functions and the coefficients quantifying the mass transfer in and around the particles are available. If further the variation of the equilibrium functions with changes in the mobile phase composition is known, this model is also able to predict gradient elution chromatography. Significant disadvantages of the model are the need to specify three kinetic coefficients and the amount of computing time required for the numerical solution of the underlying equations. Thus, several simplified models have been suggested lumping mass transfer resistances together. In this work the accuracy of predicting chromatographic bands based on the numerical solution of two lumped models has been analyzed. Elution profiles calculated by (a) the transport-dispersive and (b) the equilibrium-dispersive models were compared between each other and with the solution of the more detailed general rate model. In the analysis performed both linear and non-linear chromatography was considered under isocratic and gradient conditions.
Collapse
Affiliation(s)
- Dorota Antos
- Department of Chemical Engineering, Rzeszów University of Technology, Ul. W Pola 2, Rzeszów Pl-35-959, Poland.
| | | | | | | |
Collapse
|
29
|
Felinger A, Cavazzini A, Guiochon G. Numerical determination of the competitive isotherm of enantiomers. J Chromatogr A 2003; 986:207-25. [PMID: 12597628 DOI: 10.1016/s0021-9673(02)01919-2] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A numerical method was developed and used to determine adsorption isotherms in chromatography. The numerical parameters of an isotherm model were derived from the recorded band profiles of the racemic mixture of the 1-phenyl-1-propanol enantiomers, by means of a nonlinear least-squares method. We used the equilibrium-dispersive model of chromatography with several isotherm models. The numerical constants of the isotherm models were tuned so that the calculated and the measured band profiles match as much as possible. We show that this numerical inverse method can be applied even without the knowledge of the individual band profile of the pure enantiomers. The isotherms determined from the--usually unresolved--overloaded band profiles matched extremely well the isotherms determined by frontal analysis. Several isotherm models were used and tested--such as Langmuir, biLangmuir, Tóth, Langmuir-Freundlich. The best-fit isotherm was selected by means of statistical evaluation of the results.
Collapse
Affiliation(s)
- Attila Felinger
- Department of Chemistry, University of Tennessee, 552 Buehler Hall, Knoxville, TN 37996-1600, USA
| | | | | |
Collapse
|
30
|
|
31
|
Zhang L, Selker J, Qu A, Velayudha A. Numerical estimation of multicomponent adsorption isotherms in preparative chromatography: implications of experimental error. J Chromatogr A 2001; 934:13-29. [PMID: 11762761 DOI: 10.1016/s0021-9673(01)01297-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Since experimental methods for measuring multicomponent adsorption isotherms are extremely tedious, numerical approaches are an attractive alternative. Here, the variance in isotherm parameters as a function of experimental error in measured effluent concentrations is quantified. The number of experimental replicates needed to obtain isotherm parameters to a desired level of accuracy is calculated explicitly. After the covariance matrix of the parameters has been determined, Monte Carlo methods are found to be rapid and effective. The use of different kinds of experiments, the effect of resolution and loading, and the impact of the number of measured data points are described.
Collapse
Affiliation(s)
- L Zhang
- Department of Bioengineering, Oregon State University, Corvallis 97331-3906, USA
| | | | | | | |
Collapse
|