Thermodynamic modeling of hydrate phase equilibria in methyldiethanolamine solution in the presence or absence of monoethylene glycol
Journal of Chemical & Engineering Data
School of Engineering
As the search for natural resources extends into ever deepening waters, the oil and gas industry is faced with numerous flow assurance challenges ranging from corrosion to gas hydrate formation. Methyldiethanolamine (MDEA) is a chemical that is widely used for corrosion protection through the pH stabilization method. It is usually injected alongside monoethylene glycol (MEG) which is used as a hydrate inhibitor. In recent studies, MDEA has been found to have an inhibiting effect on gas hydrate formation. This inhibitory effect is neither taken into account in field hydrate control programs nor in simulation software. To date, the effect has only been modeled empirically by the authors. In this study, thermodynamic modeling has been conducted using the cubic plus association equation of state (CPA EoS) combined with van der Waals and Platteeuw’s solid solution theory for hydrate phase equilibria. This application of the CPA EoS will allow for accurate prediction of hydrate equilibria of MDEA solutions used in the industry. Furthermore, new hydrate phase equilibria data for MDEA and MDEA–MEG systems have been produced. A good prediction by the proposed model has been found across all available hydrate phase equilibria of MDEA systems with and without the presence of MEG in the literature.