Synergistic Hydrate Inhibition by Red Seaweed Extract K-Carrageenan With Kinetic Hydrate Inhibitors

Abstract

AbstractThe synergy between a plant-based polysaccharide k-carrageenan (k-crgn and two well-known kinetic hydrate inhibitors (KHIs), polyvinyl caprolactam (PVCap) and polyvinylpyrrolidone (PVP), is investigated, to achieve a higher hydrate inhibition performance. The effectiveness of the hydrate inhibition is assessed by measuring the induction time (IT) required for hydrate formation and by the growth rate of the hydrate plugs after nucleation. Hydrate formation tests are conducted using a constant cooling rate of 1°C/h. Experimental results of PVP and PVCap at 0.5 wt% are compared with solutions of 0.25 wt% KHIs (PVP or PVCap) blended with 0.25 wt% k-crgn to keep the equal total inhibitor concentration for a fair comparison. Results indicated that the blended mixtures (k-crgn + KHI) have higher induction times by 20–35% and up to 90% lower hydrate growth rates when compared to the IT and growth rates of PVP and PVCap. This suggests k-crgn to be an excellent hydrate inhibitor synergist to PVP and PVCap and possibly to the other commercial hydrate inhibitors.