Effect of Glucose on CH4 Hydrate Formation in Clay Nanopores and Bulk Solution: Insights from Microsecond Molecular Dynamics Simulations

A microscopic insight into the formation and growth of CH4 hydrate in glucose solution is vital to understand the accumulation of natural gas hydrate resources and develop hydrate-based technologies. Herein, microsecond MD simulations have been performed to investigate the formation and growth of CH4 hydrate in glucose solution inside and outside of the montmorillonite nanopore to examine the effects of glucose concentration and salt ions. Simulation results indicate that glucose molecules inhibit the growth and formation of CH4 hydrate by controlling the size of the CH4 nanobubbles. Specifically, glucose molecules adsorb H2O and Na+ and repel CH4, thus greatly promoting nanobubble formation and inhibiting hydrate formation. Glucose molecules adsorbed on nanobubble surfaces hinder nanobubble decomposition and inhibit hydrate growth. The higher the glucose concentration, the more unfavorable the hydrate formation. Furthermore, ions and glucose can construct abnormal cages and can also adsorb on hydrate surfaces by forming hydrogen bonds with the water in hydrate solids. These ions and glucose will pose challenges to the subsequent solid–liquid separation in hydrate-based applications. These molecular insights are of scientific and engineering significance to sustainable chemistry related to exploitation of natural gas hydrate and hydrate-based technologies, e.g., seawater desalination and juice concentration.