Plasma-assisted nanotechnology for enhancement of the rate of production and storage of natural gas hydrates: Experimental study and kinetic modeling

Abstract

In the present work, the novel technique of dielectric barrier discharge (DBD) humid air plasma has been presented for processing and functionalization of nanoparticles and enhancing the rate of methane hydrate production. It is shown that the rate of gas to hydrate (GTH) production is significantly promoted by applying the proposed DBD plasma on the surface structure of graphene nanosheets (GN). The plasma processing leads to considerable enhancement of dispersion, stability and specific surface area of graphene nanoparticles such that the gas–liquid interfacial area and fluid microconvection rate and thus the GTH conversion rate are significantly increased. It is found that at the optimum operating conditions of 60 ppm of plasma treated graphene nanoparticles at a frequency of 6 kHz, a voltage of 8 kV, and a processing time of 6 min, it is possible to achieve a 5 fold increase in GTH conversion as compared to the case of pure water in a one-hour hydrate production process. A new kinetic model for prediction of the gas to hydrate energy conversion process is also presented and the predicted results are validated by using the experimental data at different operating conditions. The average absolute deviation percent (AAD%) and the coefficient of determination (R2-value) of the predicted gas consumptions regarding methane hydrate formation process are about 1.97% and 0.98 respectively suggesting the excellent accuracy of the proposed kinetic model. The proposed plasma functionalization technique is robust and eco-friendly without operational difficulty of conventional surfactants and can have potential application for considerable enhancement of the rate of production and storage of natural gas hydrates.