Extracting
Kinetic Information from Complex
Gas–Solid Reaction Data
- Publication date
- Publisher
Abstract
We develop an approach for extracting
gas–solid kinetic
information from convoluted experimental data and demonstrate it on
isothermal carbon dioxide splitting at high-temperature using CoFe<sub>2</sub>O<sub>4</sub>/Al<sub>2</sub>O<sub>3</sub> (i.e., a “hercynite”
cycle based on Co-doped FeAl<sub>2</sub>O<sub>4</sub>) active material.
The reaction kinetics equations we derive account for competing side
reactions, namely catalytic CO<sub>2</sub> splitting on and O<sub>2</sub> oxidation of doped hercynite, in addition to CO<sub>2</sub> splitting driven by the oxidation of oxygen-deficient doped hercynite.
The model also accounts for experimental effects, such as detector
dead time and gas mixing downstream of the reaction chamber, which
obscure the intrinsic chemical processes in the raw signal. A second-order
surface reaction model in relation to the extent of unreacted material
and a 2.4th-order model in relation to CO<sub>2</sub> concentration
were found to best describe the CO generation of the doped hercynite.
Overall, the CO production capacity was found to increase with increasing
reduction temperature and CO<sub>2</sub> partial pressure, in accordance
with previously predicted behavior. The method outlined in this paper
is generally applicable to the analysis of other convoluted gas–solid
kinetics experiments