Experimental and Modeling High-Pressure Study of Ammonia-Methane Oxidation in a Flow Reactor
Pedro García-Ruiz1, Iris Salas1, Eva Casanova1
1Department of Chemical and Environmental Engineering, Aragón Institute of Engineering Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain.
Energy & Fuels : an American Chemical Society Journal
|January 24, 2024
Summary
This study analyzes ammonia-methane oxidation at high pressures, finding that increased pressure, fuel ratio, or oxygen shifts conversion to lower temperatures. Key products include N2, NO, and N2O, with a kinetic model showing good agreement with experimental data.
Area of Science:
- Chemical kinetics
- Combustion science
- Environmental chemistry
Background:
- Ammonia and methane are key components in various energy and industrial processes.
- Understanding their co-oxidation is crucial for emission control and process optimization.
- High-pressure oxidation behavior requires detailed investigation.
Purpose of the Study:
- To experimentally and computationally analyze the oxidation of ammonia-methane mixtures.
- To investigate the influence of pressure, temperature, stoichiometry, and fuel ratio on product formation.
- To validate and refine a chemical kinetic model for this system.
Main Methods:
- High-pressure (up to 40 bar) oxidation experiments in a quartz tubular reactor.
- Varying temperatures (550-1250 K) and argon dilution.
- Analysis of product concentrations (NH3, CH4, NOx, N2, COx, HCN).
- Simulation using a detailed chemical kinetic mechanism.
Main Results:
- Increased pressure, CH4/NH3 ratio, or oxygen stoichiometry shifts NH3 and CH4 conversion to lower temperatures.
- Pressure has a significant effect, especially at lower ranges.
- N2, NO, and N2O are major ammonia oxidation products; NO2 is negligible.
- N2O formation is enhanced by higher CH4/NH3 ratios and stoichiometry.
Conclusions:
- The developed kinetic model generally describes the experimental results well.
- Discrepancies between model predictions and experimental data were observed.
- The study provides valuable insights into high-pressure ammonia-methane co-oxidation chemistry.
