Effect of Pore Size Distribution on Methane Storage at Low Pressure: Preparation of Activated Carbon for ANG Storage

Abstract

Natural gas is used as fuel for automobiles due to its high calorific value and relatively clean burning fuel compared to gasoline. It can be stored by liquefaction and compression. For transportation fuel, liquefaction is impractical and requires high pressures (20MPa) and an expensive multistage compression facility. Adsorbed Natural Gas (ANG) method can be used to store natural gas at relatively low pressure (3-4 MPa) that can be achievable by single stage compression. Activated carbons prepared from cocunmut shell and activated by KOH were studied for methane storage application. The effect of different variables of the activation process (KOH/carbon ratio, pyrolysis temperature and time) on methane storage and delivery was analysed. In addition to the well known effect of the micropore volume and packing densityuy , spetial attention was paid to the effect of the micropore size distributyion has in methane storage performance. It wa shown that this parameter is also a key parameter in the application of activated carbon for methane storage application. Activated carbon prepared from a cheap raw material and using a single stage activation process has reached very high methane storage (150v/v). The experimental data were analysed usinh Toth model and data were fitted well with the model.