Hydrate Inhibition in laboratory flowloop using polyvinylpyrrolidone, N-Vinylcaprolactam and 2-(Dimethylamino)ethylmethacrylate

Hydrate formation is a major flow assurance challenge plaguing the oil and gas industry. Hydrates are non-stoichiometric crystalline compounds formed at elevated pressure and low temperature in the presence of water and gas. Hydrates are capable of depositing along the line causing flow restriction. This study investigates the effect of three kinetic hydrate inhibitors; N-Vinylcaprolactam, Polyvinylpyrrolidone and 2-(Dimethylamino)ethylmethacrylate, in a constant volume experiment conducted using compressed natural gas and water in a laboratory flow loop at 150psi for a duration of 2 h. The laboratory flow loop is a 12 m flow loop made with 316 stainless steel of 0.5inch internal diameter. The steel pipe is enclosed in a 4inch PolyvinylChloride (PVC) pipe containing cooling water. The loop is specially designed for studying hydrate formation and inhibition. Hydrate formation is indicated in the loop by an increased loop temperature, an increased differential pressure and a decreased loop pressure. It was observed that 0.05 wt% N-Vinylcaprolactam and 0.05 wt% Polyvinylpyrrolidone were effective at inhibiting hydrate formation in the loop. However, 0.05 wt% 2-(Dimethylamino)ethylmethacrylate performed poorly at inhibiting hydrate formation in the laboratory flow loop. Mathematical models describing the performance of these inhibitors in the laboratory flow loop were obtained. The experiment described in this work can be used in screening hydrate inhibitors prior to field application.