Deposits in a commercial RFCC reactor were characterized
using
an analytical approach. Further characterization of deposits on the
reactor cyclone, which are one of the primary problems causing abnormal
shut-down of RFCC, was carried out in order to understand the formation
mechanism of the deposit. The deposits in the reactor consist of hydrocarbon
and inorganic matter, compositions of which are well matched with
the RFCC catalyst. In a longitudinal analysis of a sample reflecting
age, H/C atomic ratio decreases slightly with increased aging time
in inner regions and has high value at the surface region, which is
a relatively fresh deposit. The particles, surrounded by carbonaceous
matter, and amorphous carbonaceous matter are observed through surface
micrographs. Aromatic compounds and nano- and microcatalyst fines
contribute to the formation of deposits. Micro- and nanostructure
of the deposit is amorphous or very weakly ordered. The H/C atomic
ratios of samples with different ages, over 90 days, do not change
with aging and are matched with a variation of feed API. Possible
mechanisms for the deposit formation and its reducing methods are
proposed.