Autothermal reforming of methane to syngas with palladium catalysts and an electric metal monolith heater

Abstract

The autothermal reforming of methane to syngas for use in the Fischer-Tropsch synthesis was studied in this work over PdO containing various combinations of CeO₂, BaO or SrO in a washcoated form on a metallic monolith at atmospheric pressure. This study focused on the autothermal operation of the system, in which an electric heater inside the reactor was used only to reach the ignition temperature, and thereafter the autothermal reaction successfully sustained itself without any external heat source. It was concluded from the experiments that the PdO/Al₂O₃ catalyst was better than the others, except for PdO-CeO₂-BaO-SrO/Al₂O₃, which showed similar performance in terms of the CH₄ conversion and H₂+CO selectivity, while affording a higher H₂/CO ratio (close to ca. 3) than the PdO/Al₂O₃ catalyst did (close to ca. 2). The gas hourly space velocity and O₂/CH₄ ratio governed the methane conversion, while the H₂O/CH₄ ratio controlled the H₂/CO ratio. A methane conversion of ∼87%, H₂+CO selectivity of ∼94%, H₂/CO ratio of ∼2.9, and M factor ∼2.15 were obtained under the conditions of a gas hourly space velocity (GHSV) of 120,000 h⁻¹, O₂/CH₄=0.6 and H₂O/CH₄=0.5.