Influence of the surface area/volume ratio on the chemistry of carbon deposition from methane

The chemistry of carbon deposition from methane as a function of methane pressure was studied at a temperature of 1100 °C and surface area/volume ratios of 0.8 and 3.2 mm⁻¹ by analysis of both gaseous and condensing, i.e. aromatic reaction products. Conversion of methane as well as the yields of the hydrocarbons formed increase with increasing pressure. The surface area/volume ratio has a significant influence on the formation of aromatic hydrocarbons showing much higher yields at the lower ratio. This result, expected from preceding studies of deposition rates, confirms that a change of this ratio leads to a change of the deposition chemistry of carbon.