Rafael Gonzalez - GRACE
The production of light olefins (ethylene, propylene, butylene) has become the focus for many
refineries, and the FCC unit is a key component of the refinery strategy to meet propylene
demand. W. R. Grace & Co. (Grace) is the market leader in providing refiners with catalyst
solutions to maximize valuable LPG olefins from the FCC unit across feed conditions ranging
from hydrotreated VGO to atmospheric residue. Key to the production of light olefins in the FCC
is careful selection of the base Y-zeolite catalyst and the ZSM-5 zeolite additive. This
presentation focuses on next-generation ZSM-5 additives which Grace has engineered to have
very high activity.
ZSM-5 is a shape selective zeolite used in the FCC process for improved gasoline octane and
increased light olefin yields. In 1984, Grace Davison (now Grace) introduced Additive O, the first
FCC additive incorporating ZSM-5 zeolite. Since then, Grace has been the leader in the global
ZSM-5 additives market and is committed to continued investments in research and
development in these additives. To achieve maximum yields of propylene in the FCC unit, a high
level of ZSM-5 activity is required. This can be achieved, of course, through high addition rates
of additive, although this is usually not ideal due to activity dilution of the base cracking catalyst.
A more preferred approach has been to increase the activity of the additive through
the incorporation of higher and higher levels of ZSM-5. Stabilization and binder technology is key
in achieving high levels of ZSM-5 incorporation in traditional ZSM-5 additives. However, there
is a practical limit to this approach and Grace believes the next generation of ZSM-5 additives
will have an enhancement of the unit activity of the ZSM-5 zeolite itself.
Our efforts in the laboratory have yielded very encouraging results demonstrating step out
activity increases per unit crystal of ZSM-5. We will share some preliminary results from our
work and describe expected benefits in commercial FCC units including maximizing the
production of valuable light olefins and minimizing both the production of lower value LPG
components and dilution of the Y-zeolite catalyst activity.