Comparison of ceramic honeycomb monolith and foam as Ni catalyst carrier for methane autothermal reforming

Structured ceramic honeycomb monolith and open cell foams were employed as Ni catalyst carrier for methane autothermal reforming (CH4-ATR). The catalysts were prepared through washcoating of the supports with a commercial CeO2–Al2O3-based slurry and further impregnation into aqueous solution of nickel acetate tetrahydrate. A quite good reproducible preparation procedure was individuated in terms of both washcoat loading and resistance to ultrasonic vibrations and thermal shock tests. The catalysts were characterized by means of several techniques such as XRD, SEM, N2 adsorption at −196 °C, Hg porosimetry and H2-TPR. The catalytic activity towards CH4-ATR was tested in kW-scale autothermal reforming reactor which is able to produce up to 5 m3(stp)/h of H2. The reactor is thermally integrated with two heat exchangers for the preheating of the air and liquid water fed to the system, thus being completely self-sustained and able to perform without any external heat source. The tests carried out aiming to evaluate the influence of the O2/CH4 ratio on catalytic performance showed the higher activity of foam structured samples which can provide a lower average temperature in the catalytic bed.