Studies on some alkylamide surfactant gas hydrate anti-agglomerants

Low dosage hydrate inhibitors (LDHIs) are a recently developed hydrate control technology, which can be more cost-effective than traditional practices such as the use of thermodynamic inhibitors e.g., methanol and glycols. Two classes of LDHI called kinetic inhibitors (KHIs) and anti-agglomerants (AAs) are already being successfully used in the field. This paper describes efforts to develop new classes of AA surfactant with one or two alkylamide groups in the polar head. The goal was to find an AA that was as good as commercial quaternary AAs, which would be economically competitive and more environmentally friendly. The chemistry and environmental properties of the new surfactants are described along with experiments to determine their performance carried out in high-pressure sapphire cells and a wheel loop. The results indicate positive performance for some products but not as good as a commercial quaternary ammonium-based surfactant AA. The best surfactants had one or two carbonylpyrrolidine or isopropylamide groups in the head. The performance of the best AAs was found to be dependent on the hydrocarbon phase and salinity of the water phase. (c) 2006 Elsevier Ltd. All rights reserved.