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On the kinetics and equilibria of plasma-based dry reforming of methane

Tijdschriftbijdrage - e-publicatie

Plasma reactors are interesting for gas-based chemical conversion but the fundamental relation between the plasma chemistry and selected conditions remains poorly understood. Apparent kinetic parameters for the loss and formation processes of individual components of gas conversion processes, can however be extracted by performing experiments in an extended residence time range (2ā€“75 s) and fitting the gas composition to a first-order kinetic model of the evolution towards partial chemical equilibrium (PCE). We specifically investigated the differences in kinetic characteristics and PCE state of the CO2 dissociation and CH4 reforming reactions in a dielectric barrier discharge reactor (DBD), how these are mutually affected when combining both gases in the dry reforming of methane (DRM) reaction, and how they change when a packing material (non-porous SiO2) is added to the reactor. We find that CO2 dissociation is characterized by a comparatively high reaction rate of 0.120 sāˆ’1 compared to CH4 reforming at 0.041 sāˆ’1; whereas CH4 reforming reaches higher equilibrium conversions, 82% compared to 53.6% for CO2 dissociation. Combining both feed gases makes the DRM reaction to proceed at a relatively high rate (0.088 sāˆ’1), and high conversion (75.4%) compared to CO2 dissociation, through accessing new chemical pathways between the products of CO2 and CH4. The addition of the packing material can also distinctly influence the conversion rate and position of the equilibrium, but its precise effect depends strongly on the gas composition. Comparing different CO2:CH4 ratios reveals the delicate balance of the combined chemistry. CO2 drives the loss reactions in DRM, whereas CH4 in the mixture suppresses back reactions. As a result, our methodology provides some of the insight necessary to systematically tune the conversion process.
Tijdschrift: Chemical engineering journal
ISSN: 1385-8947
Volume: 405
Jaar van publicatie:2021
Trefwoorden:A1 Journal article
BOF-keylabel:ja
BOF-publication weight:10
CSS-citation score:2
Authors from:Higher Education
Toegankelijkheid:Open