Thermodynamic analysis of autothermal steam and CO2 reforming of methane

Thermodynamic equilibrium of methane autothermal reforming was studied by Gibbs free minimization for methane and H 2 O or CO 2 conversions, H 2 yield and coke deposition as a function of H 2 O -to- CH 4 ratio, CO 2 -to- CH 4 ratio, O 2 -to- CH 4 ratio, reforming temperature and pressure. The optimal reaction conditions for reforming and the ways for coke elimination were given. The results showed that coke formed in CO 2 reforming was easier than that formed in steam reforming under similar conditions. Coke elimination should be done by increasing the reaction temperatures in CO 2 reforming while by increasing steam content fed in steam reforming. The optimal CH 4 / CO 2 / O 2 feed ratios 1:0.8–1.0:0.1–0.2 through the analysis of thermodynamic equilibrium in the oxidative CO 2 reforming were corresponding to the reaction temperature higher than 800 ∘ C . Carbon deposition increased with the increase in pressures while a high temperature can suppress this effect.