Hydrocarbon Processing - June 2021 - 46

Catalysts
ments in hardware technology, enable refiners to push profitability
up to the FCCU or to downstream process constraints.
Nevertheless, another variable exists that can significantly
improve unit profitability and reliability, resulting in substantial
economic benefits: the FCC catalyst technology. The main
advantages of catalyst technologies are:
* Wide flexibility to change design to adapt performance
to objectives
* No need to stop the unit as with major hardware
revamps, which enables changes between planned
mean-time to application recovery (MTAR) dates
* Minor costs only involved and no CAPEX needed
compared to high CAPEX investments
* Significant value creation for a refinery with optimized
catalyst system selection.
A commercially well-proven catalysth
specifically tailored
for the very adverse conditions of AOR's process was proposed.
The main characteristics of this catalyst are:
1. High-stability zeolite technology that yields
superior activity retention and hydrothermal
stability while exhibiting low hydrogen-transfer
selectivity to minimize undesired bimolecular
reactions, as well as increased low-value LPG and
gasoline linear paraffins.
2. Integration of proprietary metals traps, including
an alumina-based matrix Ni passivatori
and the rare
earth-based vanadium trap (IVT). Research has
been conducted using x-ray diffraction (XRD) to
demonstrate the interaction between γ-Al2
was also used to reduce the harmful
O3 and Ni.
As can be seen in FIG. 5, this interaction is stronger
with increasing Ni concentration. An IVT trap
technologyj
effects of V. This well-established technology has
shown excellent V inhibition, as can be seen using
a cross-section SEM-EDX microscopy technique
(FIG. 6) in contaminated Ecat samples, which
demonstrates the co-existence of hot-spots of rare
earth RE and V, thus trapping the V and preserving
the zeolite integrity.
3. Intracrystalline pore architecture is optimized
to enable large molecules often encountered in a
residual feedstock stream to enter the catalyst system
and therefore be cracked into smaller, higher value
molecules. This open pore volume is a characteristic
signature of a proprietary catalyst system seriesk
, and
it improves molecular diffusivity and pre-cracking of
heavy molecules that otherwise would interact only
on the surface of the zeolitic part of the catalyst and, in
that case, hinder both the extent and selectivity of the
monomolecular cracking aimed at the zeolite section
properly designed for residue cracking.3
This is clearly
observed when comparing the pore size distribution
(PoSD) of different commercially available catalysts
(FIG. 7). The PoSD of the catalystk
exhibits a wide
peak between 300 Å and 1,000 Å, where molecular
diffusion is much faster and in line with typical heavy
molecular size contained in resid fractions.
KMG FCCU industry benchmarking. Thanks to the combination
of state-of-the art hardware and catalyst technologies,
AOR's RFCCU is showing outstanding conversion results that
position it among the top refiners in the industry processing
heavy feeds. Typical yields achieved in the refinery's RFCCU
are indicated in TABLE 2.
These yields and conversion levels, when compared to
EMEA refineries in general at normalized yields, further sup2Theta
FIG.
5. XRD diffraction patterns of γ-Al2
O3 with Ni, from containing
no Ni (black) up to maximum Ni content (green).
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
10
FIG. 6. SEM mapping for rare earth (RE) and vanadium (V) of a
contaminated Ecat containing proprietary IVT technologyj
.
46 JUNE 2021 | HydrocarbonProcessing.com
100
Alternative resid catalyst
Optimized catalysth
Pore diameter, A
1,000
10,000
FIG. 7. Pore size distribution (Å) of optimized resid catalystk
alternative resid catalyst in the market.
and
Intensity/a.u.
Differential pore volume
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