Porous adsorbents for vehicular natural gas storage: A review

Methane adsorption data (both experimental and simulated) under conditions of direct relevance for vehicular natural gas storage, i.e., at 500 psig an d ambient temperature, has been compiled from the literature for various mi croporous adsorbents and discussed in this work. Characterization of microp orosity has been briefly reviewed, followed with a discussion on the porous structure of natural gas adsorbents. A common trend of gravimetric methane adsorption capacity scaling with surface area among the diverse microporou s adsorbents (viz., coals, carbons, zeolites, silica gel and an MCM-41 type material) is demonstrated. Further, it is substantiated and emphasized tha t increasing the adsorbent surface area on a volumetric basis is very impor tant for vehicular natural gas storage where the fuel storage volume is a c onstraint. The effect of other adsorbent properties such as heat of adsorpt ion and heat capacity on the natural gas storage capacity is also discussed .