The research of adsorption model for methane/hydrogen
and thermal effects on storage process
Abstract
Storage by adsorption of hydrogen/methane on carbon-based material such as activated
carbon has a potential application while comparing with other storage methods. However, in
practice, adsorption storage still faces such critical issues as the low storage density and thermal
effect of the storage system on the adsorption process. This paper carries out the research in
following aspects:
(1) Analysis of adsorption equilibrium model of supercritical gas on activated carbon. Ajax
Activated carbon which has a specific surface area about 1200m2 g1 was selected as an
adsorbent, isotherms of excess adsorption amount of methane were measured at temperature
from 268.15K-338.15K and pressure up to 12.5MPa. Comparisons were made between
experimental data and those predicted by Langmuir, Langmuir-Freundlich and Toth models.
Isosteric heats of methane adsorption on Ajax activated carbon were determined by adsorption
isosteres on the absolute amounts. Results show that Toth equation performs well in predicting
the equilibrium data in the whole pressure range 0-10MPa, but the results from
Langmuir-Freundlich equation have higher prediction accuracies while the pressure gets higher.
The adsorbed phase densities of supercritical methane on the activated carbon vary with
equilibrium temperatures and pressures, the mean value of isosteric heat of adsorption set by
absolute amounts is about 15.72 kJ mol1 , which is smaller than that plotted from the excess
amounts.
(2) Analysis of the
