The effects of combustion parameters on the reformer performance were studied in a 1-kW fuel cell reformer. A reformer system was numerically simulated using a simplified two-dimensional axisymmetric model domain with an appropriate user-defined function. The numerical results were compared with experimental data for validation. The fuel ratio, based on the flow rate of methane in the reforming reactor, was varied from 20% to 80%. The equivalence ratio was changed from phi = 0.5 to 1.0. The results indicated that as the fuel ratio increased, the production rates of hydrogen and carbon monoxide increased, although their increase rate reduced. In fact, at the highest heat supply rates, the hydrogen production rate was actually slightly decreased. Simulations showed that the mixture had the highest fuel conversion rates and production rates of reformate gas at certain equivalence ratio and fuel ratio. This finding implies that adjusting the equivalence ratio and fuel ratio can significantly change the reformer characteristics and that the reforming performance can be optimized by adjusting them. (C) 2013 Elsevier Ltd. All rights reserved.