Natural gas storage with activated carbon from a bituminous coal

Granular activated carbons (−20 + 100 mesh; 0.149−0.84 mm) were produced by physical activation and chemical activation with KOH from an Illinois bituminous coal (IBC-106) for natural gas storage. The products were characterized by BET surface area, micropore volume, bulk density, and methane adsorption capacities. Volumetric methane adsorption capacities ($\text{V}{}_{\mathrm{m}}\text{V}{}_{\mathrm{s}}$) of some of the granular carbons produced by physical activation are about 70 cm³/cm³ which is comparable to that of BPL, a commercial activated carbon. ($\text{V}{}_{\mathrm{m}}\text{V}{}_{\mathrm{s}}$) values above 100 cm³/cm³ are obtainable by grinding the granular products to −325 mesh (<0.044 mm). The increase in ($\text{V}{}_{\mathrm{m}}\text{V}{}_{\mathrm{s}}$) is due to the increase in bulk density of the carbons. Volumetric methane adsorption capacity increases with increasing pore surface area and micropore volume when normalizing with respect to sample bulk volume. Compared with steam-activated carbons, granular carbons produced by KOH activation have higher micropore volume and higher methane adsorption capacities (g/g). Their volumetric methane adsorption capacities are lower due to their lower bulk densities.