Research On Molecular Design Method Of Solvent Screening For Extraction Distillation Processes

Extractive distillation is commonly used to separate systems of close boiling compounds or azeotropes, and the solvent selection is critical, the computer-aided molecular design (CAMD) is used in the paper.A new method of molecular design was proposed, which can reduce the workload of molecular design efficiently. It included two parts. One was to preselect the candidate groups by investigating their selectivity for the separation system. Combining with Gani's group preselection rules, all groups were preselected comprehensively; the other was to get the range of solvents'solubility parameter by the theory of Scatchard-Hildebrand. Take the azeotrope of dimethyl carbonate-methanol for example, choose the suitable solvents using selectivity and solubility parameters, then verify the accuracy of the method and determine the appropriate operation conditions and technological parameters of the extraction distillation separation of dimethyl carbonate-methanol through simulation tool Aspen plus.The method could solve the problem of the combinatorial explosion, improve the efficiency and reliability for the selection of extraction solvents, and guide for process engineering development and industrial applications.