Numerical simulation of biogas chemical looping reforming in a dual fluidized bed reactor

Conversion technologies with low environmental impact and high energetic efficiency are needed to ensure clean, efficient, and cost-effective exploitation of renewable carbonaceous fuels like biogas. In the present study, the Chemical Looping Reforming of biogas is proposed and numerically investigated to pursue this goal. Preliminarily, a thermodynamic model was implemented by means of the Aspen Plus® commercial software to identify the conditions where carbon formation and deposition do not occur. A simple hydrodynamic model of a Dual Fluidized Bed reactor coupled with a 1D, static, and isothermal kinetic model was adopted. The effects of variations in biogas composition (namely, CH4:CO2 ratio and water content) and in other relevant process parameters (e.g., the oxygen-to-fuel ratio and FR operating temperature) on the process performances in terms of the reactants conversion degree, syngas yield, and syngas composition were assessed and critically discussed. Very high conversion degree for both CH4 (93%) and CO2 (87%), as well as syngas yield ranging up to 3.74, were evaluated.