The propylene produced contains onl

The propylene produced contains only the propane contained in the ethylene or C4 feed. This means that the propylene purity usually exceeds the polymer-grade level produced by
the majority of steam crackers, without any
superfractionators.
When integrated with a grassroots steam cracker, the
by-product flexibility of the cracker is greatly
enhanced. With high propylene value and
demand, the OCT unit can be operated to
increase the propylene-to-ethylene ratio to
above 1.0. Importing an external C4 stream can
further increase the ratio. Should propylene value
fall, the steam cracker is able to produce as much
as 115% of its nameplate ethylene capacity
while exporting either a mixed C4 stream or a C4
stream where the butadiene has been hydrogenated to butenes. Operation can thereby be optimized depending on the relative values of
ethylene, propylene, butene, and mixed C4s. This
product flexibility ensures profitable operation
as by-product values shift over the 30+ year
life-cycle of the facility.