(92c) Greener Ethylene Production Via Chemical Looping Oxidative Dehydrogenation
- Conference: World Congress on Particle Technology
- Year: 2018
- Proceeding: 8th World Congress on Particle Technology
- Group: Particle-Based Separations: Fundamentals & Applications
- Time: Wednesday, April 25, 2018 - 9:15am-9:40am
We have identified Mg6MnO8, a mixed oxide with a cation deficient rocksalt structure, to be an excellent model redox catalyst for ODH. It is capable of supplying lattice oxygen at rates comparable to the rate of hydrogen formation via thermal cracking of ethane. When promoted with alkali salts, changes in the bulk and near surface properties of the Mg/MnO system help produce ethylene with exceptional selectivity by suppressing deep oxidation of ethylene. The facile combustion of hydrogen favored by the promoted redox catalyst leads to high ethylene yield while providing the heat required for the endothermic dehydrogenation reactions. CL-ODH of ethane is modeled using ASPEN Plus® and is compared with a conventional stream cracking process. Results show that CL-ODH with 85% ethane conversion provides over 70% reduction in the overall energy demand with >75% reduction in the overall CO2 emissions. The exothermic nature of the regenerator and elimination of the steam requirement lead to major reductions in the upstream energy consumption. Preliminary results from CHEMKIN-PRO® are in close agreement with literature values in terms of product compositions for ethane cracking. Incorporation of surface kinetics of the redox catalyst towards hydrogen combustion provides further insights of the dependence of product output on the process conditions.