Glycols Partitioning At High Pressures In Gas Processing Systems

Glycols are commonly used chemicals in the gas processing industry, for example monoethylene glycol is (MEG) injected at the well head to prevent hydrate formation; glycols are also used in dehydration units to remove water from natural gas streams. Because of the low vapour pressure of glycols, limited information on glycol solubility in high pressure systems is available in the literature.
In this work, a new experimental approach is presented to determine the water and glycols concentration in high pressure gas streams. The method uses a Tuneable Diode Laser Absorption Spectroscopy (TDLAS) sensor for water detection combined with Thermal Desorption Gas Chromatography for the analysis of glycols. The setup was initially tested by measuring pure glycol solubility in methane. Water content measurements were also carried out for glycol solutions over a wide range of temperature and pressure and finally gas solubility in pure glycols and aqueous solutions were measured to tune the thermodynamic mode. The Cubic Plus Association (CPA) equation of state adjusted on experimental solubility data was used to model the distribution of glycols and water in the gas phase.