The scale-up of Taylor flow from a single capillary channel to a monolith is a critical step for
the industrial application of microchannel reactors in general and monolith catalyst supports
in particular. Characteristics of pressure drop in capillaries were used to identify the conditions
under which all channels in a monolith behave essentially identically. This eliminated upflow
as unstable and posed a criterion for the minimal stable gas and liquid velocity in downflow.
The assumption that the pressure drop over all channels is the same allowed the transformation
of feed maldistribution into a residence time distribution. The residence time of the bubble train
was rather insentitive to feed maldistribution. Experiments confirmed the limited impact of
maldistribution on the RTD for different distributors. The E curves in monoliths were described
by a piston-dispersion-exchange (PDE) model, where the dispersion term quantified the
maldistribution. Industrially relevant observations on distributor design and monoliths blocks
stacking are reported. The most important practical conclusion was that monoliths can indeed
be scaled-up using physically sound criteria.
Caterpillar catalysis: Segmented flow in standard GC capillary columns, with a heterogeneous Pd catalyst on the walls, gave rapid information about catalytic processes in them. The residence time and conversion was monitored visually, greatly simplifying bench‐scale optimization. Examples show the benefits of the elimination of pore diffusion and axial dispersion. Further, we demonstrated how to quickly identify deactivating species in multistep synthesis without intermediate workup.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.