Thermoelectric characterization of an intermediate temperature solid oxide fuel cell system directly fed by dry biogas

• Published in: Energy conversion and management 2016-11, Vol.127, p.90-102
• Main Authors: De Lorenzo, G., Corigliano, O., Lo Faro, M., Frontera, P., Antonucci, P., Zignani, S.C., Trocino, S., Mirandola, F.A., Aricò, A.S., Fragiacomo, P.
• Format: Article
• Language: English
• Subjects: Biogas; Experimental tests; Simulation model; SOFC system
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2016.08.079

•Numerical Model (NM) of SOFC Cogenerative System (SCS) fed by dry biogas is set up.•NM simulates new Ni-Fe/CGO protective layer for direct CH4 consumption at the anode.•NM simulates the anode carbonation phenomenon and is experimentally validated.•The performance parameters trends of SCS fed by three types of dry biogas are shown.•SEM images after 40h of operation show that there is no anode carbon deposition. A properly manufactured intermediate temperature Solid Oxide Fuel Cell (SOFC) can be directly fed by dry biogas, considering also the electrochemical partial and total oxidation reactions of methane in the biogas at the anode. In this way the methane in the biogas is electrochemically consumed directly at the fuel cell without the need to mix the biogas with any reforming gas (steam, oxygen or carbon dioxide). In this article, a numerical model of an SOFC system with Ni-Fe/CGO electrocatalyst anode protective layer directly fed by dry biogas, in cogenerative arrangement and with anode exhaust gas recirculation is formulated. The influences of biogas composition, of fuel cell operating current density and of percentage of recirculated anode exhaust gas on the SOFC system performances were evaluated by calculation code. An SOFC test bench was set up to validate the calculation code results experimentally. Furthermore, the numerical model also considers the anode carbonation and evaluates the amount of carbon that can be formed in the anode at chemical equilibrium and quasi-equilibrium conditions associated with the specific anode protective layer used.