Prediction Of Active Carbon Behaviour
PREDICTION OF ACTIVE CARBON BEHAVIOUR
IN METHANE STORAGE SYSTEMS
B. Buczek, L. Czepirski
University of Mining and Metallurgy, Faculty of Fuels and Energy,
al. Mickiewicza 30, 30-059 Cracow, Poland
Natural gas is a potentially attractive energy carrier for vehicular use. At present, the methods of storage (liquefaction, compression) show many disadvantages or significant drawback. These can be eliminated by using low-pressure storage systems containing adsorbents.
Physical adsorption is a method by which more gas can be stored at lower pressures by means of Van der Waals interactions at the gas solid interface when the high density of adsorbed phase is exploited. This method of storage is particularly attractive for permanent gases, which need to be stored, transported, or used in ambient temperature.
Methane adsorption data (both experimental and from literature) under conditions of direct relevance for vehicular natural gas storage, i.e. at about 3.5MPa and ambient temperature, has been compiled for various adsorbents and discussed in this work. According to the data obtained it can be conclude that active carbons appear to be a suitable medium for the storage of natural gas.
The packing and piece density of the active carbon, as well as, the volumetric methane uptake become important factors influencing the storage density. It was shown that surface area and/or micropore volume on a volumetric basis is important for vehicular methane storage where the fuel storage volume is a constraint.
The relationship taking into account the above parameters is given and discussed. To achieve greater methane storage densities, the bulk density of the carbon should be increased by eliminating voids and macropores without decreasing the volume of adsorbing pores. The increase of bulk density minimizes the dead spaces between particles. A further gain can be made by using a carbon having a low macropore volume.
Results obtained indicate that there is still room for improvement in the performance of the adsorption storage systems.
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