Thermodynamic Analysis of Propane Aromatization

Chemical equilibria of propane aromatization under both unrestricted coke-formation and coke-free operating conditions were studied. In both cases, propane conversions were nearly complete. The aromatics selectivity was observed to be 46% at a temperature of 823 K (1 bar) under coke-free operating conditions. Application of hydrogen and steam as coke-removing agents was also studied. Under coke-free operation, the presence of low level of water in the feed favors propane methanation, whereas higher levels of water enhance propane steam reforming. Methane selectivity was found to attain a maximum at H2O/C3H8 molar ratio equal to 0.75 (823 K, 1 bar). The outcomes of the present study imply that the products selectivity has to be controlled kinetically and that the catalyst formulation should be aimed at minimization of coke formation and carbon-carbon bond breakage activity.