Enhancement of methane purification by the use of porous media in hydrate formation process

Methane separation and purification was studied utilizing hydrate formation from a ternary CH4/C2H6/C3H8 gas mixture. The effect of the presence of porous media and the composition of the feed stream was investigated with respect to the enhancement of methane split fractionation and purification. Nanostructure silica-based porous material (SIPM) and a chemically modified (CHMPM1 and CHMPM2) version of this material were used at a weight ratio of 5% with three different gas compositions of the feed stream. The composition of the gas phase in equilibrium with the hydrate was determined by gas chromatography to distinguish how the components split into the two phases of gas and hydrate. The results showed that the CHMPM1 increases the gas storage capacity in the hydrate phase. Providing selective hydrate formation results in the highest methane purification in the presence of SIPM compared with that obtained using the chemically modified material and pure water. The initial feed composition affects both the final gas composition and the purification factor. The continuous stepwise hydrate formation showed good efficiency in selective gas separation when the gas in equilibrium with the hydrate phase was used as a feed for the next step. An increase in methane purification was observed when the amount of methane in the feed gas was lowered. The obtained results can provide the basis for methane separation from natural gas.

► Gas hydrates technology (HBGS) was used to separate methane from natural gas.
► The presence of low dose porous media improved the separation efficiency.
► The feed gas composition is an important factor in the gas separation using HBGS.
► Silica porous media increased hydrate storage capacity.