Ignition of homo/hetero combustion of propane in a microreactor with catalyst segmentation

The ignition behavior of propane/air mixtures in a microreactor with catalyst segmentation is investigated using 2D computational fluid dynamics simulations. The steady state ignition bifurcation and the transients during cold-start ignition in a segmented microreactor are compared with the typical case of continuous catalyst. Catalyst segmentation in microreactor allows significant reduction in the amount of catalyst without significantly affecting the ignition temperature or the time required for ignition of homo/catalytic combustion. The effect of segmentation on the rates of catalytic and homogeneous reactions, as well as the local Sherwood number is analyzed. Creating alternating segments of catalytic and non-catalytic regions is suggested in the literature in order to promote homogeneous chemistry in non-catalytic regions at steady state. However, enhancement of homogeneous combustion in non-catalytic regions does not affect ignition because sequential light-off of catalytic followed by homogeneous chemistry is observed. Finally, the effect of inlet velocity and microreactor dimensions on ignition in segmented microreactor is also presented.