Protic ionic liquids as hydrate inhibitors

Abstract

Hydrates can be defined as crystalline structures, formed by water, with cavities where light gases are imprisoned. Its formation in pipes and equipment of the petroleum industry may cause problems in terms of flow assurance for offshore petroleum and natural gas production. Hydrate formation may also compromise good functioning of primary processing in platforms. Due to favorable conditions, such as low temperature, high pressure and presence of gas, hydrate agglomerations might be formed in pipes, causing blockage of flow, which might jeopardize production by leading to local pressure increase, resulting in pipeline rupture risk. Therefore, preventing hydrate formation by inhibitor injection is common practice in the petroleum industry. However, high costs related to current inhibitor injection processes for flow assurance and the use of formulations with high inhibitor content have lead the scientific community to search for new substances with inhibitor traits. In this context, Ionic Liquids (IL) stand out, as they can behave as both kinetic and thermodynamic inhibitors. Additionally, ILs present advantages over conventional inhibitors, such as low volatility, thermal stability, low flammability and versatility. An easily synthesized and low cost type of IL is known as Protic Ionic Liquid (PIL), which will be the focus of this project. Thus, the aim of this project is to identify and investigate the applicability of PILs as hydrate inhibitors. This study is going to be divided in: pre-screening of PILs, solid-liquid equilibria of PILs in aqueous media, prediction of hydrate temperature dissociation in the presence of PILs, experimental determination of hydrate P-T diagrams with PIL addition and thermodynamic modelling of hydrate equilibria. (AU)