Thermodynamic Analysis of Hydrogen Production from the Adsorption-enhanced Steam Reforming of Biogas

Abstract

Biogas is considered a potential, renewable fuel to be used as a hydrogen source. At present, a steam reforming is widely used process in hydrogen production, but it needs to be operated at high temperature to achieve high hydrogen yield. Because biogas consists of mostly CO2, the hydrogen purification of a reformate gas obtained is another important issue, especially for fuel cell applications. In this study, an enhanced-adsorption steam reforming process in which steam reforming reaction and CO2 adsorption are occurred in a single unit is investigated. A thermodynamic analysis is performed to study effects of important operating parameters on hydrogen yield and product distribution. It is found that a biogas processor should be operated at high temperatures and inlet steam-to-methane ratio. The content of CO in the reformate gas increases with increased operating temperature. The steam reforming of biogas coupled with a CO2 adsorption gives a higher hydrogen product with considerable low CO content, compared to the conventional steam reforming of biogas.