(583dn) Partial Oxidation Reaction of Methane to Syngas At Fuel Process Systems of 1Nm3/h

In recent years, a great deal of interest has been shown in the over consumption of fossil fuels and environmental problems. Many research efforts have been made to evaluate the suitable ratio of syngas production, H₂/CO=2, for Fischer-Tropsch synthesis process. An important method for syngas production is the fuel reforming process in which a catalytic reaction of hydrocarbon such as methane, methanol, ethanol, liquefied petroleum gas, and other oil derivatives generates hydrogen and carbon dioxide. Some typical fuel reforming technologies are steam reforming, partial oxidation, autothermal reforming and CO₂ reforming etc. In general, catalytic partial oxidation has the advantage of producing syngas with lower H₂/CO ratio than that produced by steam reforming.

Currently, partial oxidation reforming process by precious metal catalysts (e.g., Ru, Pd, and Pt) has generally been used to convert methane to hydrogen. In this work, the catalytic behaviors of Ni/CeO₂-ZrO₂, Ni-Ru/CeO₂-ZrO₂, Ni-Pd/CeO₂-ZrO₂ loaded on the metallic monolith were investigated for the partial oxidation reforming reaction of methane. Ni, Ru and Pd were loaded on the CeO₂-ZrO₂ supports by the impregnation method after dissolving in 5M-HNO₃ and then these catalysts were thermally treated at 800 °C for 2h. Metallic monolith with 2.5 cm in diameter and 6 cm in height was prepared by winding a combination of flat plate and flexural plate of 50 μm thickness. Before loading the catalyst to metallic monolith, alumina sol was coated on the surface of metallic monolith for improvement of catalyst adhesion, and pre-heated at 500 °C. The catalyst slurry was washcoated on the metallic monolith of honeycomb structure that has excellent heat conductivity. Prepared supports and catalysts were analyzed by XRD, SEM and BET.

The main products obtained from the partial oxidation reaction are found to H₂, CO, and CO₂. The effect of temperature, GHSV and O₂/CH₄ ratio, was investigated to find optimum operating conditions for each processes. Among the catalysts used in the experiment, the Ni-Pd/CeO₂-ZrO₂ catalyst showed the highest activity. The 97% of CH₄ conversion and 90% of CO yield were obtained at the condition of T=900 °C, GHSV=15,000h^-1 and feed ratio O/C=0.55. In this condition, the maximum flow rate of the syngas generated from the reactor charged with 30 cc of the metallic monolith catalyst is 1.0 Nm³/h.