Dipropylene glycol as a solvent for the extraction of aromatic hydrocarbons. Analysis and evaluation of the solvency properties and simulation of the extraction processes

Solvent properties, solvation power and selectivity, are calculated for dipropylene glycol (DPG). Additionally, the performances realized by DPG in extraction columns were evaluated by simulating in PRO/II software the extraction of aromatic hydrocarbon from a fraction of Catalytic Reforming naphtha based on the binary interaction parameters obtained from liquid-liquid and vapor-liquid equilibrium experimental data for the binary mixtures of DPG with representative aromatic and non-aromatic hydrocarbons with six up to eight carbon atoms, as determined in previous works. The simulation of the extraction columns was achieved for different operating conditions: solvent mass ratios from 1:1 up to 4:1 and different numbers of theoretical trays in simple columns, solvent mass ratios from 1:1 up to 4:1 and different reflux ratios in columns operated with reflux of extract, and in columns operated with reflux of raffinate. The results show that DPG has a good solvation power, and its utilization in extraction ensures a pure raffinate is obtained. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.