(449b) Gas Hydrate Based Solidified Natural Gas (SNG) Technology Incorporating Dual-Function Promoters for Enhanced Commercialization Potential

Natural Gas (NG) has gained newfound importance in recent years as a crucial transition fuel, also spurring the inclusion of NG storage techniques within nations’ energy resilience frameworks. The gas hydrate based Solidified Natural Gas (SNG) technology is an attractive option for large-scale, long-term NG storage applications due to its ability to provide non-explosive, energy-dense storage with straightforward gas recovery. Although gas hydrate formation generally necessitates low temperature and high pressure conditions, utilizing dual-function promoters (additives that promote both the thermodynamics and kinetics of hydrate formation), rapid and energy-dense methane hydrate formation may be achieved at ambient temperature.

We have identified three different additives, namely Tetrahydrofuran (THF), 1,3-Dioxolane (DIOX) and 1,3-Dioxane (Dioxane), as dual-function promoters for the methane hydrate formation process, and thus, the SNG technology. Herein, we collate data gathered over several years of systematic research to present a holistic comparison of the performances and efficacies of these dual-function promoters. Our reportage first compares the critical physico-chemical properties of the three compounds and then focuses on their 'dual-impact' on the thermodynamics and kinetics of the mixed hydrate systems. For the latter aspect, phase-equilibrium conditions for the mixed methane hydrate systems are compared and reported, as is relevant kinetic data such as the time required to complete 90% of hydrate formation (t₉₀) and the final gas uptake. Finally, the stability characteristics of individual mixed methane hydrate pellets, synthesized using the different dual-function promoters, are discussed. The present study suggests a new direction to enhance the operational and commercial feasibility of the SNG technology.