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. K E Y W O R D S economic evaluation, monoethylene glycol (MEG), process simulation 1 | INTRODUCTION Gas hydrates (GH) are ice-like clathrates of crystalline structure formed due to the freezing of water in the gas stream leading to pipeline plugging and discontinuing the transportation of gas. The formation of GHs has significant safety risks and economic challenges to gas transportation and processing that end up with operational shutdown for an extended period. Thus, careful measures to avoid, mitigate and control the formation of these hydrates are required for offshore production sites.