The operation of simulated moving beds (SMBs) at their optimal operating conditions is difficult and not robust. Therefore, it is common practice to operate SMB units far from their economic optimum in order to tolera...
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The operation of simulated moving beds (SMBs) at their optimal operating conditions is difficult and not robust. Therefore, it is common practice to operate SMB units far from their economic optimum in order to tolerate uncertainties in the system and minimize the effect of disturbances. Recently, we have proposed an on-line optimization based SMB control scheme that allows to exploit the full economic potential of SMB technology. The goal of this work is two-fold. Firstly, to experimentally evaluate and demonstrate the capability of the controller to optimize and operate the SMB units, thus delivering the products with maximum productivity and minimum solvent consumption. Secondly, to show the suitability of the controller even using a minimum of system information, thus making the detailed isotherm measurements redundant and saving time in the separation design phase. This paper reports and discusses the first experimental implementation of the control concept on a high purity separation of nucleosides (uridine, guanosine) with an eight-column four-section SMB where the species to be separated are retained on the source 30RPC stationary phase according to a linear isotherm. (C) 2005 Elsevier B.V. All rights reserved.
The operation of simulated moving beds (SMBs) at their optimal operating conditions is difficult and not robust. Therefore, it is common practice to operate SMB units far from their economic optimum in order to tolera...
详细信息
The operation of simulated moving beds (SMBs) at their optimal operating conditions is difficult and not robust. Therefore, it is common practice to operate SMB units far from their economic optimum in order to tolerate uncertainties in the system and minimize the effect of disturbances. Recently, we have proposed an on-line optimization based SMB control scheme that allows to exploit the full economic potential of SMB technology. The goal of this work is two-fold. Firstly, to experimentally evaluate and demonstrate the capability of the controller to optimize and operate the SMB units, thus delivering the products with maximum productivity and minimum solvent consumption. Secondly, to show the suitability of the controller even using a minimum of system information, thus making the detailed isotherm measurements redundant and saving time in the separation design phase. This paper reports and discusses the first experimental implementation of the control concept on a high purity separation of nucleosides (uridine, guanosine) with an eight-column four-section SMB where the species to be separated are retained on the source 30RPC stationary phase according to a linear isotherm. (C) 2005 Elsevier B.V. All rights reserved.
The Simulated Moving Bed (SMB) is a continuous multi-column chromatographic process that has-become an attractive technology for complex separation tasks that are regularly encountered in the areas of pharmaceuticals,...
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The Simulated Moving Bed (SMB) is a continuous multi-column chromatographic process that has-become an attractive technology for complex separation tasks that are regularly encountered in the areas of pharmaceuticals, fine chemicals and biotechnology. Even though economic optimality of the SMB process has attracted significant amount of attention, operation of the SMB units at their optimal operating conditions is still an open issue due to the absence of proper feedback control schemes. Recently, we have developed an online optimization based feedback control scheme that can deliver the full economic power of the SMB technology despite disturbances and uncertainties in the system.(1,2,3) This paper focuses on the implementation of the control concept to SMBs operating under overloaded chromatographic conditions that are characterized by nonlinear competitive adsorption isotherms. It is shown that despite the overloaded chromatographic conditions, the process can be controlled and optimized based on the linear adsorption isotherm information only. The performance and robustness of the control scheme is assessed under simulated challenging operating conditions.
A new optimization based adaptive control strategy for simulated moving beds (SMBs) is proposed. A linearized reduced order model, which accounts for the periodic nature of the SMB process, is used for online optimiza...
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A new optimization based adaptive control strategy for simulated moving beds (SMBs) is proposed. A linearized reduced order model, which accounts for the periodic nature of the SMB process, is used for online optimization and control. The manipulated variables are the four inlet flow rates, the outputs are the raffinate and extract concentrations. Concentration measurements at the raffinate and extract outlets are used as the feedback information. The state estimate from the periodic Kalman filter is used for the prediction of the outlet concentrations over a chosen horizon. Predicted outlet concentrations are the basis for the calculation of the optimal input adjustments, which maximize the productivity and minimize the desorbent consumption subject to constraints on product purities. The realization of this concept is discussed and the implementation on a virtual eight column SMB platform is assessed, in the case of binary linear systems. For a whole series of typical plant disturbances it is shown that the proposed approach is effective in minimizing off-spec products and in achieving optimal SMB operation. also in the case where there are significant model uncertainties. (C) 2004 Elsevier B.V. All rights reserved.
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