A simple and flexible micro reactor for investigations of heterogeneous catalytic gas phase reactions

Heterogeneous–homogeneous interactions in catalytic microchannel reactors

“…[19][20][21] We found in experimental investigations that the Pt-catalyzed oxidation of hydrogen with air can be conducted even at stoichiometric conditions without any indication for homogeneous reactions, especially without any explosive behavior, and confirmed in a theoretical study that this behavior is consistent with wall-induced radical quenching. The importance of radical quenching for Pt-catalyzed hydrogen oxidation in "macroscopic" reactors was also demonstrated in simulation studies by Vlachos and coworkers, [22][23][24] whereas Andrae and Bjoernbom 25 confirmed that chemical (that is, kinetic) wall effects dominate over thermal wall effects, although the latter were found to increase in importance for very fuel lean mixtures.…”

“…[19][20][21] The inlet linear velocity of the gases is set to 9 m/s (corresponding to Re Ϸ 40) with a stoichiometric mixture of hydrogen and air (unless stated otherwise). The microchannel is described as a symmetric tube with the catalyst deposited on the walls.…”

“…Furthermore, Pt was used in our experimental investigations and therefore allows comparison between simulation and experimental results. 20,21 Finally, the kinetics of H 2 oxidation on Pt has been extensively studied in the past and the available reaction kinetics are therefore comparatively well tested and reliable. 14,[23][24][25][30][31][32] Results are shown in Figure 2, where results for the fully coupled heterogeneous-homogeneous reaction system in a Ptcoated microchannel reactor (filled squares and solid line) are shown compared with the purely homogeneous gas-phase ignition (circles and dashed line) and the purely catalytic ignition (that is, no homogeneous reactions; open squares and dotted line).…”

Micro-structured string-reactor for autothermal production of hydrogen

“…with a thermocouple in the middle of the catalytic bed was placed in a furnace. This design for catalyst testing was preferred to the set-up of Veser et al [18] who used a single catalytic wire placed in the center of a silicon channel. Premixed water-methanol was fed to a vaporizer (Bronkhorst High-Tech B.V.) heated at 398 K with argon as carrier gas.…”