Measuring vapor-liquid equilibria in sour gas + glycol aqueous solution using static techniques

Dehydration of natural gases is a frequently required gas processing. Dehydration is the process used to remove water from natural gases to prevent formation of gas hydrates/ice and condensation of water in production, transportation and processing facilities. In cryogenic processes, the presence of water increases manifold problems. In petrochemical industry, water in the gas streams may poison the catalysts. To remove water, glycols can be used. Ethylene glycol (EG) and tri-ethylene glycol (TEG) are the most commonly used solvents for natural gas dehydration. During the process of dehydration, the circulation of glycol aqueous solution allows absorbing given amounts of the acidic gases, like CO2. The presence of such compounds can cause the solution to be corrosive, especially at high temperatures of the regenerator. Accurate knowledge of phase behavior of the gaseous systems containing sulfur species in the presence of glycol aqueous solution is, therefore, necessary to avoid such problems. Static analytic and static synthetic methods are widely used to measure phase equilibria. In this work, we present an experimental set up based on a combination of static analytic and synthetic techniques. Phase equilibria of acidic natural gas (CO2+ CH4) in EG aqueous solutions is measured and compared with literature data sets. The method is relatively faster and cheaper and gives promising results.