Comparative Study of Methane Hydrate Formation and Dissociation with Hollow Silica and Activated Carbon

Abstract

Natural gas hydrates are ice-like crystalline compounds and non-stoichiometric, and methane is trapped inside the water cages of the hydrates. In recent years, the hydrates have received much attention for natural gas storage and transportation. However, the use of methane hydrates has faced many challenges such as slow formation rate, low growth rate during hydrate formation, and low conversion ratio of gas to solid hydrates, leading to poor storage capacity. The addition of hydrate promoter is one of alternatives that may overcome these problems. In this work, porous materials, hollow silica (HSC) and activated carbon (AC), were investigated as the hydrate promoters at saturation condition, 1:10 HSC to water and 1:1 AC, to water on the hydrate formation and dissociation. The hydrate formation was conducted in a fix bed reactor at 8 MPa and 4 ºC. The results showed that the methane hydrate formation using the HSC enhanced the water conversion to hydrates and the methane consumption at a greater extent than the methane hydrate formation using the AC. The decomposition of hydrates was performed by thermal stimulation with 21 ºC temperature driving force. The results showed that the porous materials did not significantly affect the methane released and methane recovery from the hydrates.