Kinetic evaluation of the tri-reforming process of methane for syngas production

The conversion of natural gas was carried out via tri-reforming of methane in a fixed bed reactor employing a Ni/gamma-Al2O3 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 (tau < 2.0 kg s/m(3)), a hydrogen yield as high as 75% was obtained.