Effect of biopolymers and their mixtures with glycine on the formation kinetics of methane hydrates

Abstract

In oil and gas industry formation of gas hydrates are a huge nuisance which disturbs the flow assurance. Kinetic Hydrate Inhibitors (KHIs) have been investigated, developed, and applied to retard the hydrate formation and ensure the smooth flow. Among KHIs, glycine and biodegradable polymers are investigated as potent gas hydrate inhibitors. In this work the kinetic performance of synergic materials which are the combination of biopolymers and amino acid is evaluated for inhibiting methane hydrates. Where, 0.2 wt% of biopolymers including Pectin (PC), Sodium-Carboxymethyl cellulose (Na-CMC), Tapioca starch (TS) and Xanthan gum (XG)) are mixed with 5 wt% of glycine (G). The investigation is conducted by isochoric constant cooling method on sapphire reactor at 9.5 MPa and temperatures of 274 K and 277 K. Three main factors i.e., induction time, hydrate formation rate and mole consumption of methane are observed to determine the formation kinetics of methane hydrates. In addition, percentage relative inhibition strength (%RIS) of biopolymer + glycine mixtures are compared with literature. Results revealed that, G + XG delayed the induction time to 47 min at 274 K and reduced the hydrate formation rates at 277 K. As for mole consumption, G + XG and G + PC consumed the least amount of gas.