The ExSact catalyst performance has been validated in a
pilot using untreated MTBE raffinate feed as the olefin source.
In anticipation of the commercial reactor design, we chose
a pilot-plant configuration that included multi-staged olefin
feed with product recycle. The pilot-unit was designed carefully
by maintaining the same scale-up parameters in the pilot
unit as in the commercial scale reactor. Inter-phase heat
and mass-transfer effects are important for liquid acid alkylation
reactors but do not play a major role in the solid-acid alkylation
process.
The product octane and catalyst activity obtained over a
pilot test is shown. Variations in the octane result from
altering process conditions including feed composition and
olefin space velocity. Catalyst stability was confirmed by
measuring the catalyst performance through multiple cycles
of alkylation and regeneration using hydrogen. Alkylation
cycles were typically 12 hours, followed by a 2-hour regeneration
cycle. The time-on-stream reported here refers to the cumulative
time of the alkylation cycles only.
There is no activity loss over repeated cycles of alkylation
followed by regeneration as measured by olefin conversion,
product octane or alkylate yield. The product octane is significantly
higher than that obtained with liquid-acid processes under
similar operating conditions and feedstocks. It is important
to note that the olefin feed (which contains over 3500 ppm
of di-olefins, 700 ppm of oxygenates and 0.6 ppm of acetonitrile)
was used untreated for these tests.
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