SOFC Running on Biogas: Identification and Experimental Validation of "Safe" Operating Conditions

Abstract

This work concerns the feasibility of SOFC operation directly on biogas and more specifically, the optimization of biogas internal dry reforming conditions. A special attention is paid to the carbon deposition risk. For such a purpose simulation tools have been developed, based on thermodynamic and electrochemical modelling, in order to determine the risk of carbon formation within the anode during operation. Safe operation conditions in terms of temperature, fuel composition and cell polarization have been established and validated experimentally. In conditions where carbon deposition is expected, performance degradation upon operation has been followed over more than hundred hours on complete cells (Cermet Ni-8YSZ//8YSZ//LSM) by electrochemical impedance spectroscopy. The carbon deposited has been characterized by scanning electron microscopy with particular attention given to its morphology and distribution.