Abstract
This paper documents the development and performance of a nano-phase Ru catalyst on a (BaO)x(CaO)y(Al2O3)z support. Extensive screening of the support's ternary composition shows the best stoichiometry is (BaO)2(CaO)(Al2O3), denoted B2CA. The paper first describes catalyst preparation and characterization. The paper reports a detailed 12-step reaction mechanism that represents ammonia synthesis over wide ranges of temperature, pressure, space velocity, and feed composition. The mechanism is developed and validated using results of packed-bed experiments. The elementary reaction pathways consider surface adsorbates, including catalyst-poisoning behaviors. The rate expressions include important coverage-dependent activation barriers. Machine learning models assist interpretation of the catalyst-support interactions. The detailed chemistry is much more predictive than is possible with global representations (N2+3H2⇌2NH3). The validated models can be applied to assist optimizing reactor design and operating conditions.
Original language | English |
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Article number | 116902 |
Journal | Chemical Engineering Science |
Volume | 247 |
DOIs | |
State | Published - Jan 16 2022 |
Funding
This work was supported by the Advanced Research Projects Agency-Energy (ARPA-E) through the REFUEL program (Award No. DE-AR0000808) and OPEN program (Award No. DE-AR0000685).
Keywords
- Ammonia synthesis
- Heterogeneous catalysis
- Machine learning
- Microkinetics
- Packed-bed reactor
- Ru/B2CA