The conversion of natural gas was carried out via tri-reforming of methane in a fixed bed reactor employing a Ni/c-Al 2 O 3 catalyst. The kinetic evaluations were performed in a temperature range from 923 to 1,123 K under atmospheric pressure. The effects due to water and oxygen addition to the feed of the process were examined in terms of the yields of hydrogen and carbon monoxide. Contributions of the reverse water-gas shift and oxidation reactions were evaluated. At temperatures above 1,000 K, methane and carbon dioxide conversions of 97.35 and 46.75% produced hydrogen and carbon monoxide with yields of 37.35 and 4.99%, respectively. A model was proposed to describe the kinetic behavior of the process considering the proposition of a four step reaction mechanism. The solutions of the equations of the model established predictions in terms of reactant and products concentration evolutions. The model predictions indicated that for operations at 1,123 K and 1.0 bar, with low spatial times (s \ 2.0 kg s/m 3 ), a hydrogen yield as high as 75% was obtained.

A reforming experiment was performed using a nickel catalyst, with the goal of suggesting a mechanism for the autothermal reforming of methane (ATR), under thermally neutral conditions. To bring the process to future scale-up at a fixed-bed reactor, kinetic-operational evaluations were made while taking into account the parameters of the gas phase flow and the temperature. From these evaluations, based on conversions, yields, and selectivities, it was possible to develop a novel approach to a descriptive mathematical model of the process behavior. A thermodynamic evaluation of the ATR was performed to measure the effects of operational conditions (temperature, pressure, and composition of the feed), in relation to the established limit values of the chemical equilibrium.

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