Hydrocarbon Processing - December 2022 - 20

Catalysts
END OF RUN
400
395
390
385
380
375
370
365
360
355
350
345
340
50
100
150
200
250
loading and reactor internals
to better understand how to
maximize the performance of
fixed-bed catalytic reactors.
y = 0,0727x + 350
Rz
= 0,5954
EOR temperature limit
Target run - 14m (03/2022)
Actual WABT trend line
WABT
Actual WABT trend forecast
300
350
Days of run
FIG. 10. Graph showing the evolution of WABT and extension of EOR time.
vs. sock loading and CDL, and
can thus load as much as 30%
more catalyst by weight (FIG. 7).
* Increased homogeneity: Optimal
load rates enable catalyst particles
to fall freely and separately across
the full diameter of any reactor.
In doing so, particles have time to
settle in more stable, consistent
and horizontal arrangements,
resulting in more homogeneous
loading density over the entire bed
volume. This improves the liquid/
gas distribution and lowers the risk
of hotspot development within the
catalyst bed. Additionally, HDL
can load to within 30 cm of the
overlying dispersion trays, thereby
eliminating the need for top-up
by sock loading. This reduces the
risk of liquid/gas maldistribution
and hotspot development.
* Excellent catalyst integrity:
HDL uses low-friction materials
and brushes at the mouths
of the dispersion channels to
minimize damage to catalyst
particles, thereby eliminating
nearly all dust and fine particles.
Strategic benefits of HDL. HDL provides
multiple strategic benefits that
make it the smart choice for operators
looking to maximize unit and hardware
performance, and ROI.
Improved safety. Safety should be the
top priority for any operator. By eliminating
the need for personnel to enter the
reactor and by only requiring a single person
to install and dismantle the machinery,
HDL enables a much safer environment
for catalyst handlers.
20 DECEMBER 2022 | HydrocarbonProcessing.com
Higher yields. Enhanced liquid/gas
flow distribution, optimized WHSV and
improved vapor-liquid-catalyst interactions
maximize product output per unit
of run time.
Lower TCO. Although the initial price
may be higher than alternative solutions,
HDL can generate a healthy ROI by providing
a cost-effective way to safeguard
the performance of expensive catalyst and
reactor internals, and to also reduce lifetime
maintenance costs.
Longer run time and less downtime.
With no maldistribution, EOR temperatures
are not reached prematurely, so the
best use is made of the catalyst activity
(FIG. 8). Additionally, the efficiency with
which HDL machines can be loaded
and dismantled can save as much as two
shifts' worth of labor and time over the
course of a cycle. Case Study 2 provides
an example of how unit run time can be
extended by using HDL.
Reassurance. Knowing that catalyst is
well loaded means one less thing for the
operator to worry about.
How to minimize the risk of maldistribution.
To obtain the best performance
out of expensive catalyst and state-of-theart
reactor internals, an increasing number
of operators are unlocking major business
value by embracing the long-term strategic
benefits of high-quality HDL. To achieve
this, reactor operators should:
* Be proactive in understanding the
importance of catalyst loading
in reactor performance-getting
catalyst loading right at the start
can save a lot of time, money
and stress in the long term.
* Speak with experts on catalyst
400
450
500
550
600
650
* Think long term to ensure that
short-term goals do not compromise
the overall performance and
success of the project.
Case Study 1: Eliminating hotspots.
A process engineer for a mineral oil plant
in Brazil reported that significant temperature
anomalies (hotspots) had developed
in a small, 0.9-m-diameter reactor. Using
data from pairs of temperature sensors
positioned inside the catalyst bed, the engineer
calculated a temperature increase of
as much as 20°C (68°F) from one side of
the reactor to the other-a clear indication
of maldistribution.
Deciding that the catalyst needed reloading,
the engineer opted for the HDL
method and technology. Following reloading,
the temperature variation across
the reactor was reduced to 3°C (37°F),
which indicated that the maldistribution
had been eliminated-a highly satisfactory
result for the engineer (FIG. 9).
Case Study 2: Extending run time. A
reactor operator at an oil refinery in the
Czech Republic was planning to reload
catalyst for two gasoil hydrotreater reactors
of 2.8 m and 3.3 m diameters. Previously,
loading was done using whip-based
CDL; however, because of restrictive internal
configurations, the quality of the
loading was suboptimal.
The operator instead chose the HDL
method and technology, and, after 7 mos,
observed better performance in terms of
reduced WABT. Based on new projections,
the time to reach the EOR temperature
of 395°C (743°F) was extended significantly
beyond the initial 14-mos target
(FIG. 10).
NOTES
a Shell's high-dispersion (HD) tray
b
CREALYST-Oil's CALYDENS® advanced catalyst
loading system
EDWIN MAAS is the Licensing Technology Manager,
Reactor Internals, at Shell Catalysts & Technologies.
JULIEN SIGAUD is a Senior Hydroprocessing
Technologist at Shell Catalysts & Technologies.
GUILLAUME POUSSIN is the Group Managing Director
at CREALYST-Group.
THIAGO CALDAS is the Business Development
Co-Director at CREALYST-Oil.
WABT (ºC)
http://www.HydrocarbonProcessing.com
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