Steam vs. Dry Reformer: Experimental Study on a Solid Oxide Fuel Cell Short Stack

Solid Oxide Fuel Cell (SOFC) systems operating with methane usually are equipped with an external reformer to produce syngas. The conventional applied technology is steam methane reforming. Recent studies, instead, are presenting dry reforming as potential alternative. Advantages come from the substitution of steam with CO2 to be handled in the system, representing a potential strategy of CO2 reuse. This study compares, the performance of a SOFC short stack operating with dry reforming and with steam reforming mixtures respectively. Results show that higher performances can be obtained under same operating conditions, due to the high concentration of syngas (that has low content of inert species) produced via dry reforming. The analysis of different dry reforming concentrations shows that the amount of methane seems to be more relevant, in terms of voltage performances, than high hydrogen concentration. Among tested dry reforming compositions, the most performing exhibits an improvement of at least 5% in produced voltage in the range 150-375 mA cm(-2) with respect to mixture produced by steam reforming (S/C ratio of 2.5). It was also proved that this performance enhancement does not imply greater thermal stresses, since stack temperature slightly reduces and lower temperature variations arise at anode and cathode when operating current varies.