Multifunctional Two-Stage
Riser Catalytic Cracking
of Heavy Oil
- Publication date
- Publisher
Abstract
The continuous deterioration of feedstocks, the increasing
demand
of diesel, and the increasingly strict environmental regulations on
gasoline call for the development of fluid catalytic cracking (FCC)
technology. To increase the feed conversion and the diesel yield as
well as produce low-olefin gasoline, the multifunctional two-stage
riser (MFT) FCC process was proposed. Experiments were carried out
in a pilot-scale riser FCC apparatus. Results show that a higher reaction
temperature is appropriate for heavy cycle oil (HCO) conversion, and
the semispent catalyst can also be used to upgrade light FCC gasoline
(LCG). The synergistic process of cracking HCO and upgrading LCG in
the second-stage riser can significantly enhance the conversion of
HCO while reducing the olefin content of gasoline at less expense
of gasoline yield. Furthermore, the novel structure riser reactor
can increase the conversion of olefins in gasoline. Because of the
significant increase of HCO conversion, the fresh feedstock can be
cracked under mild conditions for producing more diesel without negative
effects on the feed conversion. Compared with the TSR FCC process,
in the MFT FCC process, the increased feed conversion, diesel and
light oil yields can be achieved, at the same time, the olefin content
of gasoline decreased by approximately 17 wt %