A two-column version of a multicolumn, semi-continuous, open-loop chromatograph for chiral separation is presented and validated experimentally. The heart of the process is a flexible node design and cyclic flow-rate ...
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A two-column version of a multicolumn, semi-continuous, open-loop chromatograph for chiral separation is presented and validated experimentally. The heart of the process is a flexible node design and cyclic flow-rate modulation that succeed at keeping the mass-transfer zone inside the system without resorting to any recycling technique. One advantage of this streamlined design is the simplicity of its physical realization: regardless of the number of columns, it only requires two pumps to supply feed and desorbent into the system, while the flow rates of liquid withdrawn from the system are controlled by material balance using simple two-way valves. A rigorous model-based optimization approach is employed in the optimal cycle design to generate a solution that is physically realizable in the experimental apparatus. The optimized scheme for two-column operation supplies fresh feed into the system where the composition of the circulating fluid is closest to that of the feedstock fluid, and recovers the purified products, extract and raffinate, alternately at the downstream end of the unit while desorbent is supplied into the upstream end of the system. The feasibility and effectiveness of the two-column process are verified experimentally on the separation of reboxetine racemate, a norepinephrine re-uptake inhibitor, under overloaded conditions. Our set-up employs an automated on-line enantiomeric analysis system, comprising an analytical HPLC set-up with two UV detectors to monitor the composition profile at the downstream end of one of the columns;this monitoring system does not use a polarimeter. (C) 2010 Elsevier B.V. All rights reserved.
An advanced method for optimal planning of open-loop medium voltage (MV) distribution network is proposed in this paper. The multiobjective planning model of open-loop MV distribution network is formulated, and an out...
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An advanced method for optimal planning of open-loop medium voltage (MV) distribution network is proposed in this paper. The multiobjective planning model of open-loop MV distribution network is formulated, and an outage cost calculating method applicable for open-loop MV distribution networks is proposed. To solve the optimization problem, a special Multiobjective Genetic Algorithm (MOGA) is designed based on the network dataset built by Component Geographical Information Systems (ComGIS). The network analysis function of the ComGIS is embedded in the overall optimization process of the MOGA to find single-loop optimal paths. Crossover and mutation operator are designed according to characteristics of the coding. The evolutionary orientation is directed by the fitness function based on the Pareto order of individuals. The Pareto Optimal Set (POS) including several candidate planning schemes is obtained through the MOGA, from which the recommended scheme is selected. The practicability of the method is tested by its application to a real distribution system. (C) 2008 Elsevier B.V. All rights reserved.
In this paper, an advanced method for the planning of open-loop medium voltage (MV) distribution network is proposed. The multiobjective planning model is constructed, and a special multiobjective genetic algorithm (M...
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ISBN:
(纸本)9787564112493
In this paper, an advanced method for the planning of open-loop medium voltage (MV) distribution network is proposed. The multiobjective planning model is constructed, and a special multiobjective genetic algorithm (MOGA) is designed based on the network dataset built by Component geographical information systems (ComGIS). The network analysis function of the ComGIS is embedded in the overall optimization process to find single-loop optimal paths. Crossover and mutation operator are designed according to characteristics of the coding. The evolutionary orientation is directed by the fitness function based on Pareto order of individuals. The Pareto optimal set (POS) including several candidate planning schemes is gotten through MOGA, from which the recommended scheme is selected. The method has been applied to real life power distribution networks, showing its potential in practical applications.
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