Sodium alginate polymer as a kinetic inhibitor of methane hydrate formation

Abstract

Gas hydrates are ice-like compounds that can affect the flow assurance in oil and gas pipelines due to their structural characteristics. Alginate is a polysaccharide naturally derived from the brown seaweed Phaeophyceae and is produced as an extracellular material by bacteria, such as Pseudomonas and Azotobacter. The novelty of using alginate as a natural gas hydrate inhibitor was investigated in this paper. To predict the amount of methane hydrates that formed over time, a modified Johnson−Mehl−Avrami−Kolmogorov model (JMAK) was applied. It is noted that for the studied polymer, lower concentrations of 0.1% (wt./vol) showed better inhibitory potential, and acidic pH was favorable to this behavior. The system that behaved best against methane gas hydrate inhibition was 0.1% (wt./vol) pH 4. Alginate showed a good inhibitory capacity. The JMAK model was found to be suitable for describing the crystallization kinetics of the studied systems. The kinetic parameters were calculated for this model. This study describes a new way to explore the potential of alginate as a kinetic inhibitor by delaying the formation of hydrates.