Application of multiobjective optimization in the design of chiral drug separators based on SMB technology

Abstract

The multiobjective optimization in the design of continuous countercurrent separation units based on simulated moving bed (SMB) technology is considered. In addition, the Varicol system, which is based on a non-synchronous shift of the inlet and outlet ports instead of the synchronous one used in the SMB technology is also considered. The optimization of SMB unit is quite complex as it includes relatively large number of decision variables both continuous variables, such as flow rates and lengths, as well as discontinuous ones, such as column number and configuration. Moreover, it is important to formulate the optimization problem as multiobjective, since the factors affecting the economy of chiral drug separation process are multiple and often in conflict with each other. A typical example is simultaneous maximization of the productivity of both raffinate and extract streams with a specific purity. An adaptation of genetic algorithm has been used to optimize the SMB and Varicol systems using a literature available model validated with experimental results for a chiral separation. This paper compares the optimal separation performance that can be achieved with the SMB and the Varicol technologies.