BIOGAS FROM ANAEROBIC DIGESTION AS BIOGENOUS FUEL FOR SOLID OXIDE FUEL CELLS: AN EXPERIMENTAL ASSESSMENT WITH A SIMULATED SYNGAS

摘要

Solid oxide fuel cells high flexibility on fuel typology allows to foresee their future use with a large spam of biogenous fuels. Coupled with their high efficiency in energy transformation, this characteristic could become a useful basis for plants devoted to the reduction of greenhouse gas emissions, and for the widespread use of residential renewable fuels. An interesting feature is the use of biogas from anaerobic digestion of algae cultures. This is an high quality fuel in terms of permanent gas compounds and impurities consisting mainly of hydrogen (around 60%) and the rest CO_2. However some requirements have to be taken into account concerning the presence and the effect of gas trace compounds like sulphur, halides and others on the cells' anodes. Before using a real biogas, a investigation on the effects on the cell behavior and degradation can be made with a syngas of similar composition. This paper investigates the utilization of the syngas simulating the biogas in single planar cells. Planar solid oxide fuel cells with NiO/YSZ traditional anodes were tested in order to evaluate the electrochemical cell performance. The evaluation was achieved by taking current voltage measurements at different temperatures and syngas composition. Also thermodynamic calculations were conducted to account for water gas shift and Boudouard reactions.