Kinetic effect of hydrogen addition on natural gas premixed flames

The chemical structure of laminar premixed natural gas flame with and without 60% of hydrogen on the fuel has been studied experimentally and numerically at atmospheric pressure. This work completes our recent results reported for low-pressure premixed flames. Both flames have been stabilized under similar conditions (similar cold velocity and C/O). Stable mole fraction profiles have been obtained by gas chromatography, FTIR and GC-MS. Temperature profiles have been measured by thermocouple and corrected from radiation losses. Comparatively to low pressure, more traces species have been observed at atmospheric pressure. These new results have been modeled and a revised version of GDF-Kin®3.0-NCN is reported. This version is able to predict the present data (mole fraction profiles and recent burning velocities of natural gas and natural gas/hydrogen flames) without alteration of previous predictions. Reactions path analysis confirms that hydrogen enhances H-abstraction reactions by H atoms under lean conditions. It also enhances the oxidation of C1 sequence and disfavors the C2 sequence. Consequently, a reduction of C2 intermediate specie mole fraction could be observed.