Polymerization and Performance Investigation of Poly(vinyl alcohol)-g-acrylamide as Gas Hydrate Kinetic Inhibitor

In present work, poly(vinyl alcohol)-g-acrylamide was synthesized with two initiator systems, which contain ceric ammonium nitrate and ammonium persulfate/sodium metabisulfite redox systems. The structure of the graft copolymers was confirmed by Fourier Transform InfraRed (FT-IR) spectroscopy and ThermoGravimetric Analysis (TGA). The inhibition effects of produced graft copolymers (as new kinetic hydrate inhibitors) and polyvinyl alcohol were investigated on gas hydrate formation with a methane-propane mixture which forms the structure II of the hydrate. In all experiments, the initial pressure was adjusted at 23 bar, temperature at 2 ˚C, and the stirring rate at 400 rpm. All of the tested materials reduce hydrate formation rate and their inhibition strength was PVA-g-AAM1<PVA<PVA-g-AAM2, respectively. Experimental results and kinetics of hydrate formation showed that the PVA-g-AAM1 graft copolymer decreases the average growth rate of hydrate to 11% in comparison with hydrate formation with pure water. Also, PVA-g-AAM2 graft copolymer decreases this rate to 29% which show its more suitable potential as an environmentally friendly new kinetic inhibitor.