Kinetic Modeling of Total Oxidation of Propane over Rhodium
The heat release rates of fuel-lean propane/air mixtures over a rhodium wire catalyst were measured with microcalorimetry experiments and simulated with a 2D reactive code. Based on these studies, global reaction parameters of the total oxidation of C3H8 over Rh were extracted and a full catalytic reaction mechanism was developed. Wire microcalorimetry experiments were performed at atmospheric pressure and temperatures up to 900 K, while surface kinetic data was determined within the kinetic-controlled regime below 630 K. The dissociative adsorption of C3H8 on Rh and its subsequent decomposition reaction were fitted based on the global reaction parameters, and a thermodynamically consistent reaction mechanism for the total oxidation of C3H8 on Rh was constructed by incorporating these two fitted steps into a CH4-Rh surface mechanism. The constructed catalytic reaction mechanism well reproduced the measured heat release rates in the wire microcalorimeter and was further validated against 2D Raman measurements of major gas-phase species concentrations in an Rh-coated planar channel. Moreover, when working in conjunction with a recently reported pressure dependence of catalytic reactivity and a detailed gas-phase chemistry, the developed catalytic reaction mechanism excellently captured the catalytic reactivity and the homogeneous ignition during hetero-/homogeneous combustion in the planar channel at pressures up to 6 bar. The hetero-/homogeneous coupling of the intermediate species (such as CO) appreciably affected the onset of homogeneous ignition, while the corresponding coupling via radical (O, H and OH) reactions was very weak. Finally, the key reactions controlling catalytic ignition and homogeneous ignition during hetero-/homogeneous combustion were identified.
R. Sui et al., "Kinetic Modeling of Total Oxidation of Propane over Rhodium," Combustion and Flame, article no. 111847, Elsevier, Nov 2021.
The definitive version is available at https://doi.org/10.1016/j.combustflame.2021.111847
Mechanical and Aerospace Engineering
In Press, Corrected Proof
Keywords and Phrases
Catalytic combustion of propane; Pressure dependence of catalytic reactivity; Rhodium catalyst; Surface kinetics; VOC abatement
International Standard Serial Number (ISSN)
Article - Journal
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17 Nov 2021