Simplified Kinetic Modeling of Propane Aromatization over Ga-ZSM-5 Zeolites: Comparison with Experimental Data

This paper presents new results about experimental tests and kinetic modeling of propane aromatization on a Ga-ZSM-5 zeolite. The presence of gallium as a doping metal promotes dehydrogenation reactions, limiting the formation of side products (cracking fuel gas) and increasing the yield to aromatics. In this study, kinetic tests of propane aromatization at different values of reaction temperature (500, 525, and 550 °C) and contact time (0.07, 0.14, and 0.28 h) are performed in a multi-tubular reactor, aiming at investigating the complex reaction scheme of propane aromatization at a constant pressure (3 bar). Based on the obtained experimental data, a kinetic analysis is performed considering cracking products (methane and ethane/ethylene) and main aromatic compounds (benzene, toluene, xylenes, and ethylbenzene). This simplified approach is found to be a robust tool to predict products distribution when experimental data points are not enough to perform a reliable model parameters estimation. In the specific case, the adopted macroscopic kinetic model nicely predicts the catalyst behavior in terms of both propane conversion and products distribution. The kinetic parameters evaluation for the synthesized Ga-ZSM-5 sample also suggests a reaction temperature of 525 °C as an optimum value to favor the aromatization rather than the cracking of propane. (Graph Presented).