Dehydration units are often overdesigned, resulting in high capital or operating costs. In order to ensure design options meet the necessary requirements of saving capital, solvent or energy costs, thermodynamic modeling and a holistic view of operations is needed. This paper discusses the dehydration modeling technology available with Aspen HYSYS in V10 and above. Aspen HYSYS has historically employed the glycol property package for TEG. With the addition of the Cubic-Plus-Association (CPA) package in V10, Aspen HYSYS can be used to model dehydration with TEG, MEG and DEG.