Abstract
In this paper, we investigate the power generation performance of a small-scale tubular solid oxide fuel cell (SOFC), in particular the effects of steam content in fuel flow on the terminal voltage are discussed. In the present experiments, hydrogen and nitrogen mixture, of which volume ratio H_2/N_2 was adjusted at 5%/95%, was supplied into the anode side of the single cell. The performance curves, i.e., the relationships between current and voltage, were measured on the different fuel flow rate conditions and the constant furnace temperature of 800℃. At the same current output operation, the voltage of the wet fuel supply was lower than that of the dry fuel case. In order to investigate the influence of steam addition on the voltage drop, we tried to measure the voltage loss, which was caused by the electrical and ionic resistance, through the current-interruption method. As a result, it is found that the ohmic voltage drops in the wet and the dry cases account for 9% and 27% to the total voltage drops, respectively. The absolute value of the ohmic loss is independent on the steam content. Hence, we guess that the larger voltage loss in the case of the wet fuel results from activation and concentration overpotentials.
