Methane storage in wet carbon of tailored pore sizes

Abstract

Based on the storage mechanism of methane in wet carbon, the pore size of activated carbon must match the dimension of methane hydrates, and 1.6–2.8 nm was recognized as the optimal pore size. Targeting at the optimal pore size, a progressive activation process was applied on corncob precursors and a carbon possessing abundant pores of the optimal size was prepared. Both gravimetric and volumetric storage capacity of the carbon were experimentally measured, and a theoretical volumetric capacity (TVC) was defined on discussing the transformation from gravimetric to volumetric capacities. It was shown that pore volume and pore size of carbon are decisive factors for the storage capacity, which was greatly raised up through pore size optimization. Sixty three weight percentage of the gravimetric storage capacity, 290 and 204 V/V of the TVC and experimental volumetric storage capacity were reached, which were the highest amounts reported in literature. Compared to CNG (compressed natural gas), the storage method in wet carbon stored same quantity of methane at half storage pressure.