Formulation of steam-methane reforming rate in Ni-YSZ porous anode of solid oxide fuel cells

• Published in: Heat and mass transfer 2018-08, Vol.54 (8), p.2497-2505
• Main Authors: Sugihara, Shinichi, Kawamura, Yusuke, Iwai, Hiroshi
• Format: Article
• Language: English
• Subjects: Cermets; Constraining; Engineering; Engineering Thermodynamics; Heat and Mass Transfer; Industrial Chemistry/Chemical Engineering; Ion beams; Methane; Original; Partial pressure; Pressure dependence; Reaction kinetics; Reforming; Scanning electron microscopy; Solid oxide fuel cells; Thermodynamics; Yttria-stabilized zirconia; Yttrium oxide; Zirconium dioxide
• ISSN: 0947-7411; 1432-1181
• DOI: 10.1007/s00231-018-2299-1

The steam-methane reforming reaction on a Ni-YSZ (yttria-stabilized zirconia) cermet was experimentally investigated under atmospheric pressure and in the temperature range from 650 to 750 °C. We examined the effects of the partial pressures of methane and steam in the supply gas on the reaction rate. The experiments were conducted with a low Ni contained Ni-YSZ cermet sheet of thickness 0.1 mm. Its porous microstructure and accompanied parameters were quantified using the FIB-SEM (focused ion beam scanning electron microscopy) technique. A power-law-type rate equation incorporating the reaction-rate-limiting conditions was obtained on the basis of the unit surface area of the Ni-pore contact surface in the cermet. The kinetics indicated a strong positive dependence on the methane partial pressure and a negative dependence on the steam partial pressure. The obtained rate equation successfully reproduced the experimental results for Ni-YSZ samples having different microstructures in the case of low methane consumption. The equation also reproduced the limiting-reaction behaviours at different temperatures.