2 research outputs found
Utilization of dielectric properties assessment to evaluate the catalytic activity and rate of deactivation of heterogeneous catalysts
The
use of dielectric property assessment to gauge the catalytic
activity and rate of deactivation of heterogeneous catalysts is reported.
Four supported catalysts containing a combination of Fe and Ni active
sites and γ-Al<sub>2</sub>O<sub>3</sub>, ZSM-5, MCM-41, and
SBA-15 supports were synthesized, characterized, and utilized to catalyze
a Fischer–Tropsch process over a temperature range of 250–400
°C that was specifically directed toward the production of lower
olefins. While the highest conversion was obtained from ZSM-5 and
MCM-41 supports containing Fe and Ni as active sites at 350 °C,
all these catalysts were observed to be deactivated by the formation
of carbon on their surface. The dielectric properties of the fresh,
used catalysts and supports were evaluated and correlated with their
catalytic activity and structural/textural properties. It was clearly
shown that the dielectric property measurement could demonstrate both
the presence and magnitude of carbon deposits on the catalyst via
the differences in the values of fresh and used catalysts. Furthermore,
the ability to differentiate between the levels of the carbon deposition
observed was shown to be independent of the morphology exhibited by
the carbon deposit demonstrating that this is a method that can be
generally applied