Oxidative pyrolysis reforming of methanol in warm plasma for an on-board hydrogen production

To achieve on-board hydrogen production with high energy efficiency and low energy cost, the oxidative pyrolysis reforming (OPR) of methanol using air as an oxidant in a heat insulated gliding arc plasma reactor is explored. Effects of dioxygen/methanol (O-2/C) ratio, steam/methanol (S/C) ratio and specific energy input (SRI) on the OPR are investigated. The reaction rate ratio (a) of pyrolysis reforming to oxidative reforming in the OPR is deduced. The OPR of methanol strongly depends on the O-2/C ratio, with which methanol conversion increases rapidly. In the OPR, methanol conversions occur mainly by the oxidative reforming (partial oxidation) at the O-2/C ratios below 0.20, but by the oxidative reforming and the promoted pyrolysis reforming at the O-2/C ratios above 0.20, which is confirmed by the enthalpy change for the overall reaction of OPR. Higher O-2/C ratio results in higher energy efficiency and lower energy cost, however, higher S/C ratio or larger SRI leads to lower energy efficiency and higher energy cost. Under conditions of O-2/C = 0.30, S/C = 0.5, SEI = 24 kJ/mol, energy efficiency of 74% and energy cost of 0.45 kWh/Nm(3) with methanol conversion of 88% are achieved. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.