Chemical Engineering April 2019 - 20

DeDietrich
pressure drop by arranging
flat sinusoidal
strips into an extreme
open structure, maximizes
capacity by film
flow preference on continuous
sinusoidal-strip
arrangements, increases
efficiency by minimizing
droplet formations
inside the packing and
decreases fouling tendency
by reducing droplet
development and offering
low pressure drop.
Fouling sensitivity is also
reduced by generating
continuous liquid films,
wetting the entire packing
element.
Likewise, AMACS has
been doing research to
improve its SuperBlend
product. " Research has
shown that by replacing
existing random packing
with our SuperBlend
2-PAC, tower efficiency
can be increased by
20% or capacity by 15%, " says
Moize Turkey, manager, applications
engineering, with AMACS. The
SuperBlend 2-PAC technology is a
blend of high-performance packing
sizes placed in a single bed. " We
blend two sizes of the best metal
random geometry and, when combined,
the patented blend achieves
the efficiency benefits of the smaller
packing size, while retaining
the
capacity and pressure drop of the
larger packing size, " he says. The
blended bed is recommended
for absorption and stripping, fine
chemical distillation, refinery fractionators
and retrofit opportunities
in any mass- or heat-transfer tower
limited by conventional or third-generation
random packing.
Improvements to internals are also
being developed to assist with issues
such as fouling and difficult conditions.
" Reliability is extremely important
for day-to-day considerations. No
matter how well a device performs,
if
it can't stand up to the fouling
conditions in a process, it won't be
successful, " says Mark Pilling, manager
of technology USA with Sulzer
20
suitable
FIGURE 4. DeDietrich focuses on
columns and internals for highly
corrosive processes at temperatures
up to 390°F. Columns up to
DN1000 are made of QVF borosilicate
glass 3.3 or DeDietrich
glass-lined steel. Bigger columns
up to DN2400 are made of DeDietrich
glass-lined steel only. The
corrosion-resistant materials are
made of borosilicate glass 3.3, SiC,
PTFE or tantalum
for
(Winterthur, Switzerland;
www.sulzer.com). " Sulzer
has spent a tremendous
amount of time over the
last five years developing
a complete line of
fouling-resistant equipment. "
In trays, the company
offers VG AF and
anti-fouling trays, and
recently launched UFM
AF valves, which are both
high performance for capacity
and efficiency, as
well as extremely fouling
resistant. In packings,
the company launched
Mellagrid AF anti-fouling
grid packings, which are
highly
fouling packing
applications, such as vacuum tower
wash sections.
Pilling adds that for foaming issues,
Sulzer has been working on
a two-pronged approach. " While
we develop equipment and designs
to handle foaming applications, we
also work with our customers to
determine potential foaming applications, "
he says. " Once you know
foaming exists, you can design for
it. It's the cases where a customer
will have a foaming condition and
not know about it that tend to create
problems. We see all sorts of
foaming, such as Marangoni, Ross
foams and particulate foams and
work with customers
such situations. "
to identify
And, for applications where fouling
and coking can be very severe,
Koch-Glitsch developed Proflux severe-service
grid packing, says Nieuwoudt
(Figure 1). The new high-performance
severe-service grid packing
combines the efficiency of structured
packing with the robustness and
fouling resistance of grid packing. It
is an assembly of sturdy corrugated
sheets welded to heavy-gauge rods.
The combination of welded rod assembly
and corrugated sheets of increased
material thickness provides
a robust design that resists damage
from tower upsets or erosion. The
gaps between the sheets provide
improved fouling resistance. " The
packing has been installed almost
100 times now in very severe-fouling
services and is really doing well compared
to the products it is replacing.
The longer run life and the lower pressure
drop it provides results in lower
operating costs for the customer, "
says Nieuwoudt.
Addressing specific challenges
When it comes to distillation, there
are also often challenges specific to
a process that need to be addressed
through special measures.
" There is a market for tailor-made
solutions that are tuned to the specific
process and customer needs, "
says Christian Geipel, managing director,
with RVT Process Equipment
(Steinwiesen, Germany; www.rvtpe.
com). " This is especially valid for
revamps of existing plants that are
modified to fulfill new demands. The
challenges are various and include
objectives such as longer and more
predictable run lengths for fouling
applications, higher capacity and
lower pressure drop or wider operating
ranges for more flexibility. "
To address specific needs, RVT
has developed a high-capacity
structured packing, the SP-Line
(Figure 2). " Due to modified channel
geometry, lower pressure drop
and higher capacity are achieved. "
Further, for very low liquid loads, another
application-specific challenge,
these packings can be combined
with new types of liquid distributors.
" An improved spray nozzle distributor
that combines spray nozzles with
splash plates was developed and
is successfully used in applications
like refinery vacuum columns, " says
Geipel. " It reduces entrainment and
therefore fouling in the packing sections
above the distributor without
sacrificing liquid distribution quality
to the packing section below. "
Another new liquid distributor from
RVT (Figure 3) is a trough-type disCHEMICAL
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APRIL 2019
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Chemical Engineering April 2019

Table of Contents for the Digital Edition of Chemical Engineering April 2019
