Oxidative dehydrogenation of propane with CO2 - A green process for propylene and hydrogen (syngas)

Abstract

The CO2 oxidative dehydrogenation of propane (CO2-ODHP) reaction provides a platform to utilize carbon dioxide, a greenhouse gas and commonly available propane, in the production of value-added chemicals. A thermodynamic study of the process was achieved by simulation in the Aspen Plus software, using the method of minimization of Gibbs free energy. Sensitivity analysis was performed while varying the feed CO2/C3H8 molar ratio. At higher CO2/C3H8 molar ratios, lower temperatures are required to achieve higher propane conversions. The selectivity towards propylene production increased with lower CO2/C3H8 ratios and higher temperatures. It was found that a feed with CO2/C3H8 molar ratio of 1.0 was the optimum to obtain a syngas ratio (H2/CO) of unity without compromising propylene product, at 850 °C and 1 bar. At higher CO2/C3H8 molar ratios, selectivity towards CO is enhanced, thus results in lower syngas ratios (H2/CO), whereas for a specific feed CO2/C3H8 molar ratio higher temperatures favor selectivity to H2, resulting in relatively higher syngas ratios.