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Catalytic Reforming
*Increasing the octane number of a low-octane
naphtha fraction
* the key process for obtaining benzene, toluene,
and xylenes (BTX).
Reformer Feeds
•heavy naphtha fraction
•naphtha from other sources


Reforming Catalysts
The catalysts generally used in catalytic reforming are dual
functional to provide two types of catalytic sites,
hydrogenation-dehydrogenation sites and acid sites.
The former sites are provided by platinum, which is
the best known hydrogenation-dehydrogenation catalyst
and the latter (acid sites) promote carbonium ion formation
and are provided by an alumina carrier. The two types of
sites are necessary for aromatization and isomerization
reactions.


Aromatization


Aromatization



dealkylated.


Catalytic Cracking
Catalytic cracking (Cat-cracking) is a remarkably versatile and
flexible process. Its principal aim is to crack lower-value stocks
and produce higher-value light and middle distillates. The
process also produces light hydrocarbon gases, which are
important feedstocks for petrochemicals
Feeds
The feeds to catalytic cracking units vary from gas
oils to crude residues.


FCC (fluid catalytic cracking) feedstocks are often
pretreated to decrease the metallic and asphaltene
contents.
Residium fluid catalytic cracking (RFCC) has gained
wide acceptance due to a larger production of gasoline
with only small amounts of low-value products


Cracking Catalysts
Acid-treated clays were the first catalysts used in
catalytic cracking processes, but have been replaced by
synthetic amorphous silica-alumina, which is more active and
stable. Incorporating zeolites (crystalline alumina-silica) with
the silica/alumina catalyst improves selectivity towards
aromatics. These catalysts have both Lewis and Bronsted
acid sites that promote carbonium ion formation.