Tailored Amine Oxides─Synergists, Surfactants, and Polymers for Gas Hydrate Management, a Minireview
Malcolm A. Kelland
Abstract
High Resolution Image Download MS PowerPoint Slide Low-dosage hydrate inhibitors (LDHIs) are used to prevent gas hydrates from plugging upstream gas and oil flow lines. LDHIs come in two main classes, kinetic hydrate inhibitors (KHIs) and anti-agglomerants (AAs). KHIs delay the hydrate formation process, while AAs ultimately disperse any formed hydrates so that no deposits or plugs are formed. Currently, KHI formulations deployed in the field contain one or more water-soluble polyamides with optimized hydrophobic groups, while most commercialized AAs are cationic quaternary ammonium surfactants also with optimized hydrophobic groups. The amine oxide group is closely related to quaternary ammonium salts but has zero overall charge and is also related to the amide group as a result of strong hydrogen-bonding properties. In the past decade, small amine oxides as KHI synergists, polyamine oxides as stand-alone KHIs, and amine oxide surfactants as AAs have all been developed. This review summarizes all contributions to the development of amine-oxide-based LDHIs. This includes powerful monoamine oxide synergists for polyamide KHIs, high-salinity-compatible polyamine oxide KHIs, and bis-amine oxide surfactants that function as both KHIs and AAs.