Carbon deposition in methane reforming with carbon dioxide

Coke formation in the dry reforming of methane was studied using a thermobalance (TG) and with a catalytic microreactor in the temperature range 800–950 K. Silica-supported and lanthana-supported nickel catalysts were examined. The effects of process variables such as temperature and gas composition (He dilution, CH₄/CO₂ ratio) on the coke formation rate were determined. The reactivity of H₂ on several kinds of carbon was also investigated. The morphology of the coke was studied by scanning electron microscopy (SEM). The induction times for coke formation were significantly affected by temperature and by the CO content in the feed gas. The results of catalytic tests were consistent with the TG measurements. The behaviour of SiO₂ and La₂O₃ supported Ni catalysts agree with a mechanism in which the lanthana support plays an important role in the carbon deposition.