Fundamental Science of Gas Storage

Abstract

High-pressure adsorption measurement of supercritical gas needs accurate particle density which should be obtained by high-pressure He buoyancy measurement. As the surface excess mass adsorption is not greatly larger than the bulk gas contribution in the adsorbed layer, the absolute adsorption amount containing the bulk gas contribution in the adsorbed layer must be used for thermodynamic analysis and evaluation of the storage amount. The plot of the compression factor of adsorbed layer against the inverse of the average adsorbed layer density provides the Henry, virial, and cooperative types, giving information on the strength of the gas-solid interaction. The nanoporous material showing the cooperative type is promising for the storage of the target gas. Two factors of the strength of the gas-solid interaction and the surface area predict that nanopores consisting of narrow belt walls are promising for gas storage. Molecular simulation of methane in the graphitic pore over the wide temperature range from 120 to 300 K indicates an upward shift of the critical temperature of methane adsorbed in the graphitic pore. The heat of adsorption of methane in the graphitic pore without the heat-releasing mechanism elevates the temperature of the graphitic carbon by 70 K, decreasing the adsorption amount of methane by 30%; an efficient heat releasing mechanism must be installed in the storage device.