Steam reforming of aliphatic hydrocarbons with nonthermal plasma

Steam reforming of aliphatic hydrocarbons such as methane, ethane, propane, and neopentane was investigated with two types of barrier discharge plasma reactors. With a ferroelectric packed-bed reactor ( FPR) in N₂, almost the same conversions were obtained for ethane, propane, and neopentane, but methane was less reactive than these hydrocarbons. Hydrogen gas yield decreased in the order: methane≈ethane>propane>neopentane. The molar ratio of H₂ to CO {[H₂]/[CO]} exceeded 3.5 for all the hydrocarbons. [H₂]/[CO] did not change in the range of H₂O content from 0.5% to 2.5%. At the volumetric ratio of H₂O to Hydrocarbon=2.0, carbon balances were poor for ethane, propane, and neopentane, but almost all of the carbon atoms in the reacted methane were recovered as CO and CO₂. The mole fractions of CO and CO₂ depended on the chemical structures of the substrate hydrocarbons. It is considered that the water-gas-shift reaction proceeds backward for the reaction systems of the hydrocarbons with higher hydrogen atom densities per molecule. FPR maintained the same performance for 10 h in the steam reforming of methane. The efficiency of a silent discharge plasma reactor was much lower than that of FPR.