Experimental Study of CH4-CO2 Replacement in Gas Hydrates in the presence of nitrogen and graphene nanoplatelets

Vast methane hydrates found in seabeds dispersed throughout ocean sediments and permafrost areas are a potential source of revenue as they act as an energy source. The encapsulation of carbon dioxide into the spaces occupied by methane molecules also creates a storage solution for greenhouse gases. This replacement reaction has two purposes; the first is energy release in the form of CH4 gas and the second is CO2 storage. This article presents experimental results on the CH4-CO2 replacement process using a. laboratory scale reactor with pure water and nanoparticles. Furthermore, the addition of nitrogen, as well as the use of thermal stimulation was studied experimentally to assess the enhancement of the replacement reaction. Additives such as graphene and sodium dodecyl sulfate (SDS) were utilized in the methane hydrate formation to further enhance the rate of hydrate formation. The experimental measurements show that a gas mixture of 80 mol%N2/20 mol%CO2 yields a CH4 replacement efficiency of 17.04 %, while 28.77 % replacement efficiency was the highest CH4 replacement efficiency obtained using thermal stimulation with pressurized CO2. The highest amount of CO2 sequestrated was 57.03 %. This was achieved via thermal stimulation with pressurized CO2. The lowest CO2 sequestrated was 10.57 % with 90 mol% CO2/10 mol%N2. The results confirm the significant improvements in CH4 hydrate formation, CH4 replacement efficiency, and CO2 sequestration ratio using graphene and SDS solutions. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Vast methane hydrates found in seabeds and permafrost areas can be used as an energy source and provide a storage solution for greenhouse gases by encapsulating carbon dioxide. The article presents experimental results on the replacement process using a laboratory reactor and various additives to enhance the reaction.