Experimental activity of distillation, thermodynamic model and simulation for performance analysis of a glycol reclaiming unit

The use of a glycol reclaiming unit as a side device in a TEG regeneration section in natural gas plants reduces the continuous accumulation of contaminants in TEG. The scope of this study is to investigate performances of a reclaimer by describing a thermodynamic model of vapour–liquid and vapour–liquid–liquid equilibria for the mixture of TEG with hydrocarbons and water, fitting experimental distillation data. A UNIFAC group-contribution method approach has been applied to fit data, contaminants behaviour in TEG has been described at infinite dilution conditions.The reliability of the model has been verified by process simulation with eni in-house CheOpe.

► Natural gas dehydration by means of TEG, TEG recovered by a reclaiming unit.
► A phase separation drum should be installed to improve reclaiming efficiency.
► UNIFAC-based thermodynamic model for investigating recovery of exhausted TEG.
► Model reliability verified by process simulation and by experimental trials.
► Phase separation is correctly predicted by the model described.