Effects of biopolymers on methane hydrate formation in dispersed ice

Abstract

In recent years, there has been an increased interest in the search for environmentally friendly and biodegradable substances that prevent gas hydrate formation — hydrate inhibitors. Generally, the study of the influence of inhibitors on the hydrate growth rate and their thermodynamic equilibrium is carried out at positive temperatures in liquid aqueous solutions. Given the great risk of ice formation at industrial enterprises in the conditions of the Arctic region, this article displays the influence of inhibitors on the phase equilibrium conditions and the growth rate of methane hydrates in frozen water disperse systems (FWDS). Green water-soluble substances (biopolymers) such as sodium alginate and guar gum were used as hydrate inhibitors. To obtain kinetic and thermodynamic data on hydrate formation, all experiments were carried out in the temperature and pressure ranges from 272.3 to 275.3 K and from 2.5 to 5 MPa, respectively. The study has revealed that the addition of sodium alginate and guar gum in the FWDS led to reduction hydrate formation rate and water to methane hydrate conversion. Thus, over a period of 1000 minutes, the water conversion for samples with sodium alginate (0.15 wt.%) and guar gum (1 wt.%) was 0.13 and 0.15, which is significantly less than the value degree of transition for samples of dispersed ice without the addition of biopolymers (0.26). Additives of sodium alginate and guar gum were found to be a slight increase in the equilibrium conditions for methane hydrate formation.