Solid oxide fuel cells can be fed not only by conventional fuels (methane or hydrogen), but also by nonconventional fuels such as syngas (H2, CO, N2, CO2, H2O). In terms of CO/H2 ratio, N2, CO2 and H2O concentrations, and mass flow, the anodic gas mixture composition can affect SOFC performance and create a carbon deposition phenomenon. In this paper a careful analysis of SOFCs performance for varying concentrations of the gas components of a generic stream of syngas and operating conditions (pressure, temperature), was performed in order to plan the actual test campaigns. This study showed that the CO/H2 ratio is the parameter to which must be given the most attention. This factor not only directly affects the performance of the fuel cell, but also affects its useful life, because carbon deposition is directly determined by the concentration of CO in the gas-mixture. The ratio has been found that provides the best performance without incurring in carbon deposition, which is in the range 20/80 ÷ 35/65. The paper reports a first stage of analysis (Part 1), whereas the second stage of analysis is reported in a subsequent paper (Part 2) where performances are assessed with regards to main operating parameters.

Solid oxide fuel cells are very promising devices for clean energy. Their goodness is amplified by fuel flexibility opening the possibility of fuelling with alternative and clean fuels such as syngas, deriving from biomass conversion treatments. This paper follows a first paper (Part 1) where analysis in terms of fuel composition, specifically in terms of CO/H2 ratio, were carried out, mainly to outline the field that enables a secure functioning far from carbon deposition. In this paper (Part 2) a careful analysis of SOFCs performance for varying concentrations of the gas components of a generic stream of syngas (H2, CO, N2, CO2, H2O) and operating conditions (pressure, temperature, flow rate of the gas-mixture), was performed in order to plan the actual test campaigns. The effects the significant parameters have on fuel cell performance will then be exhibited by the analysis of the planned testing campaigns to be performed on a generic laboratory prototype.