Adsorbed Renewable Energy Gas Storage

Abstract

Gases like hydrogen and gas mixtures like biogas are an important renewable energy resource. For storing, the gas is compressed and transferred to pressure vessels A sustainable and effective alternative is the adsorption of the gas by porous media. Adsorbed gas storage is of particular relevance for vehicles, where the fuel storage volume is limited. The storage performance of activated carbon beds for methane, carbon dioxide, hydrogen and the binary mixtures with methane is investigated. A lumped parameter model is used to describe composition, pressure, mean temperature and flow rate. The Dubinin-Astakhov isotherm is used to describe the adsorbed amount at different temperatures and pressures. The resulting set of transient differential equations is solved numerically. The charging process with regard to filling time and temperature is examined. The discharge process with regard to discharge rate, concentration and temperature is investigated. The charge and discharge time are significantly influenced by the heat of adsorption. For the outlet flow the composition of the gas mixture changes over time.