Synergetic effects of polyacrylamide and nonionic surfactants on preventing gas hydrate formation

•First account on effect of polyacrylamide and surfactants on hydrate inhibition.•Strong hydrate inhibition effect at very low concentrations of additives.•Comparison of the results with previously studied synergetic systems.

The aim of this work is to conduct an experimental investigation on the synergetic influence of polyacrylamide (PAM), some non-ionic surfactants and polymers on the ethane hydrate formation kinetics. The surfactants and polymers used in the experiments belong to the family of nonylphenol ethoxylates (NPE), lauryl alcohol ethoxylates (LAE), polyvinylpyrrolidone (PVP), polyethylene glycol (PEG) and ethylene oxide/propylene oxide copolymer (EO/PO). All experiments have been performed in an isochoric batch reactor under high pressure conditions. It is found that synergism of PAM and surfactants exhibits strong inhibition of ethane hydrate at experimental subcooling temperature of 10.5 °C. The experimental studies prove that the synergism of a very low dosage of PAM and surfactants not only delays the induction time but also dramatically lowers the hydrate formation rate.