Light gas solubility data determination in Deep Eutectic Solvents at high pressure

Abstract

The oil and natural gas industry is growing and has been developing new techniques for capturing its resources in deep ocean waters (offshore production). Like the onshore production, offshore seeks to obtain petroleum and natural gas derivatives to transform them into raw materials with higher added value and useful to the population. However, offshore production acts in the ideal conditions for hydrates formation, ie, high pressures and low temperatures.Gas hydrates are solids formed from hydrogen bonds between water molecules that end up forming networks that trap light gas molecules such as methane, nitrogen and carbon dioxide under appropriate temperature and pressure conditions. These solids, in turn, are responsible for the clogging of industrial pipelines, causing significant financial losses as well as disruptions in the production, distribution and transportation chain. Generally, industries, in order to avoid the formation of gas hydrates, use chemical inhibitors that act by forming hydrogen bonds with the water molecules preventing the formation of hydrates. Although efficient, the most commonly used inhibitor, monoeethyleneglycol (MEG), is a high-value and difficult-to-recover compound, encouraging the search for alternative solvents such as the deep eutectic solvents (DESs).DESs are formed by mixing up two or three components of high purity and low cost, which, due to the attractive forces, form a eutectic mixture. They can be produced on a large scale and in addition, they are biodegradable and have been mentioned in several studies as substitutes for organic solvents in the absorption of gases, such as carbon dioxide, at atmospheric pressure. Thus, this PhD project has as main objectives: (i) to determine phase equilibrium data of five types of pure DESs at high pressures; (II) to obtain light gas solubility data in DES at high pressures in order to verify which DES is the best gas absorber and to analyze possible structural changes; (III) to study the influence of temperature, pressure and amount of water in the absorption process. The data will be modeled using State Equations (EOS) and Gibbs Excess (GE) energy models to predict the behavior of the phases and their properties as a function of pressure and temperature.