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Mons-lez-Liège, Belgium

Grosfils V.,Roosevelt University | Kinnaert M.,Roosevelt University | Vande Wouwer A.,Service dAutomatique
2007 European Control Conference, ECC 2007 | Year: 2015

The Simulated Moving Bed (SMB) technology is a continuous chromatographic process which is important in various fields, from sugar to enantiomer separation. Operating conditions must be carefully selected and regulated. The optimization, monitoring and control of SMB units require the use of a process model and the estimation of the model parameters. A systematic numerical procedure for determining parameters of SMB models from batch experiments is presented and evaluated. In contrast with previous studies, parameter identifiability (including parameter sensitivity, model selection, experiment design and the influence of local minima on the optimization problem) is studied and errors on the estimated parameters are calculated. © 2007 EUCA. Source


Torres Zuniga I.,National Autonomous University of Mexico | Vande Wouwer A.,Service dAutomatique
Computers and Chemical Engineering | Year: 2014

The Varicol process exhibits continuous and discrete-time dynamics and can be represented by a hybrid model, where the continuous-time dynamics is described by mass-balance partial differential equations, whereas the discrete-time dynamics is described by a timed transition Petri net (TTPN). This hybrid model allows to simplify the solution of a normally difficult Mixed-Integer Non-Linear Programming problem for maximizing the productivity of a Varicol process subject to constraints on the desired purities of the extract and the raffinate components. Indeed, the coverability tree of the TTPN can be constructed to generate a set of candidate integer parameters, and the corresponding nonlinear problems are solved for a subset of candidates selected on the basis of an approximate evaluation using the (true moving bed) triangle theory. The optimal solution is the Varicol configuration (column sequence) for which the productivity is maximal. A repeatability and a robustness analysis show the feasibility of this approach. © 2014 Elsevier Ltd. Source


Grosfils V.,Roosevelt University | Hanus R.,Roosevelt University | Wouwer A.V.,Service dAutomatique | Kinnaert M.,Roosevelt University
Journal of Chromatography A | Year: 2010

In this study, a systematic numerical procedure for identifying the model parameters of simulated moving bed (SMB) separation processes is developed. The parameters are first estimated by minimizing a weighted least-squares criterion using experimental data from batch experiments, e.g. the time evolution of the concentration of elution peaks. Then, a cross-validation is achieved using data from experiments in SMB operation. At this stage, the importance of a careful modelling of the dead volumes within the SMB process is highlighted. In addition, confidence intervals on the estimated parameters and on the predicted concentration profiles are evaluated. © 2010 Elsevier B.V. Source


Dewasme L.,Service dAutomatique | Renard F.,Service dAutomatique | Vande Wouwer A.,Service dAutomatique
2007 European Control Conference, ECC 2007 | Year: 2015

In this paper, two robust RST control schemes for the regulation of either the ethanol concentration or the dissolved oxygen concentration in cultures of S. cerevisae are presented and illustrated with various simulation and experimental results. Both controllers only require the prior knowledge about one stoichiometric coefficient and only one on-line measurement signal, making them easily implementable in an industrial environment. Disturbance rejection is ensured thanks to an on-line parameter adaptation procedure, which delivers as a side product an estimate of the growth rate that can be used for process monitoring purposes. The robustification of the controllers is achieved in a simple way, using the observer polynomial. Additional issues, such as the presence of a delay in the system response (as observed in real-life experiments) or non negligible sensor dynamics, are also addressed. © 2007 EUCA. Source


Dewasme L.,Service dAutomatique | Richelle A.,Roosevelt University | Dehottay P.,Glaxosmithkline | Georges P.,Glaxosmithkline | And 3 more authors.
Biochemical Engineering Journal | Year: 2010

In this paper, experimental investigations of an adaptive RST control scheme for the regulation of the ethanol concentration in fed-batch cultures of S. cerevisiae is presented. Our main objective is to prove efficiency and robustness of this controller in experimental applications ranging from laboratory to industrial scales. The controller only requires one on-line measurement signal, making it easily implementable in an industrial environment. Disturbance rejection is ensured thanks to an on-line parameter adaptation procedure, which delivers as a side product an estimate of the growth rate that can be used for process monitoring purposes. The robustification of the controller is achieved in a simple way, using the observer polynomial. © 2009 Elsevier B.V. Source

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