Design, optimization and economic analysis of a monoethylene glycol recovery process: salt precipitation and vacuum operation

Abstract

In the present study, the energy requirements, performance and economic feasibility of monoethylene glycol (MEG) recovery process (MEG-R-P) were establish based on Aspen Plus simulation. The simulation was carried out in two designs and four scenarios related to the composition (mono and divalent salts) of rich-MEG. The results revealed that, under optimized conditions, a process consists of a vacuum flash separator and distillation column operated at 0.05 bar recovered 99.7% of MEG with a purity of 99.9 wt% MEG for all scenarios. The concentration and type of dissolved solids showed a minimal effect on the process of energy and performance due to high dilution. The net present worth (20 years, 8%) of the capital and operating costs associated with MEG-R-P were 11.5 and 11.7 MMUSD, respectively, representing two to four folds saving compared with published results. The recovered MEG can be recycled 10 times with an estimated saving of 50% of the total MEG purchasing cost for one-time recycling, and up to 80% saving for five times recycling. Obtained results confirm the high economic and environmental benefits achieved by applying the proposed MEG-R-P.