Dry autothermal reforming (DATR) from biomass derived gas (BDG) under excess enthalpy with porous medium (PM) is investigated in this study. Preheating reactant by internal heat recirculation of a PM may enhance the reaction of input mixture and improve production of H-2-rich syngas. Temperature distribution of catalyst and fuel conversion efficiency are studied with various feeding rates of reactant and PM under high-temperature and carbon-rich conditions. Fuel conversion and H-2-rich syngas selectivity are improved by reactant preheating with increased enthalpy of reactant by the heat transfer stored in PM. Control parameters include methane feeding rate, CO2/CH4 and O-2/CH4 molar ratios, and PM material. Experimental results indicate that reformate gas temperature with PM-assisted dry autothermal reforming is higher than the equilibrium adiabatic temperature. The results are helpful to understand the internal heat recirculation under excess enthalpy reaction. In the reforming, it not only provides the required energy for a self-sustaining reaction, but also enhances fuel conversion efficiency. The improvements in methane conversion efficiency is 18%, energy loss percentage 20.7%, and reforming efficiency 33.9%, respectively with the best parameter settings by an OBSiC PM. Additionally, the theoretical production is calculated by the HSC Chemistry software (ChemSW Software, Inc.). (C) 2012 Elsevier B.V. All rights reserved.