Methane Adsorption Properties in Biomaterials: A Possible Route to Gas Storage and Transportation

Abstract

Methane can be stored in biomaterials rapidly in hydrate form with low energy consumption. Considering the high cost of biomaterials (vegetables or fruits), agricultural wastes may be more practical. In this work, the characteristics of methane storage in two low-cost agricultural wastes, eggplant, and static water, are studied and compared. The methane adsorption rates and capacities were greatly enhanced in three biomaterials compared with that in the static water, while only corncob pith maintained relatively high gas adsorption capacity (72 v/v) and adsorption rate (~0.0300 MPa/min) in repeatable gas adsorption-desorption processes. Further investigations on the gas adsorption behavior in the corncob pith revealed that the porous structure of corncob pith generates larger specific surface areas, providing more nucleation sites for hydrate nucleation. In addition, the hydrophobic and hydrophilic performance of corncob pith components also affect the hydrate formation. The porous structure of corncob pith reduces its water activity, which decreases the stability of methane hydrate (~0.6 MPa higher at 273.15 K for equilibrium pressure than bulk phase). These results demonstrate the great gas adsorption performance and mild storage-transportation conditions of low-cost agricultural wastes and provide significant information in promoting their application in gas storage and transportation.