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Kinetic Analysis and Upper Bound of Ethylene Yield of Gas Phase Oxidative Dehydrogenation of Ethane to Ethylene

Dar, Hassan J., Nanot, Sandro U., Jens, Klaus J., Jakobsen, Hugo A., Tangstad, Elisabeth, Chen, De
Industrial & Engineering Chemistry Research 2012 v.51 no.32 pp. 10571-10585
atmospheric pressure, byproducts, cracking, dehydrogenation, engineering, ethane, ethylene, ethylene production, kinetics, models, quartz, steam, temperature
The gas phase oxidative dehydrogenation of ethane (ODHE) has been investigated, both experimentally and through kinetic modeling and simulation, as a potential alternative to steam cracking for ethylene production. The experiments were carried out at isothermal conditions and atmospheric pressure by using a quartz tube flow reactor (2 mm i.d.) with a volume of 0.110 mL. A gas phase kinetic model with 134 elementary reaction steps and 25 species was adopted from the literature, and the parameters were adjusted by best fitting of the experimental data based on the sensitivity analysis of the kinetic model. Further, the model was reduced based on the contribution analysis and a kinetic model of 41 steps involving 23 gas phase species was established. The kinetic analysis of the gas phase ODHE reaction is performed by means of the established kinetic model to provide the reaction pathways for ethylene and other byproducts formation, providing a better understanding of the radical chemistry for limiting the ethylene selectivity. The reactor simulations are performed under different conditions such as C₂H₆/O₂ ratios and temperatures to search for the upper bound of the ethylene yield in the gas phase ODHE. An upper bound ethylene yield of 53.5% (C₂H₄ selectivity, 65.4%) is predicted at 1173 K and C₂H₆/O₂ = 3.33 with a residence time of 0.1 s at atmospheric pressure.