The effects of CO addition on the autoignition of H2, CH4 and CH4/H2 fuels at high pressure in an RCM

Autoignition delay times of stoichiometric and fuel-lean (phi = 0.5) H-2, H-2/CO, CH4, CH4/CO, CH4/H-2 and CH4/CO/H-2 mixtures have been measured in an Rapid Compression Machine at pressures ranging from 20 to 80 bar and in the temperature range 900-1100K. The effects of CO addition on the ignition of H-2, to 50% CO in the fuel, and CH4, to 20% CO in the fuel, are observed to be negligible both experimentally and computationally for the conditions studied here. The addition of syngas to methane results in ignition behavior that resembles an equivalent methane/hydrogen fuel mixture with the same hydrogen fraction. In contrast to results previous presented in the literature, we thus observe no inhibiting effect from CO for the conditions in our experiments. (C) 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.