Written by M Roza

1. 1s
Detail of a Shell ConSep
tray offering extremely high
capacity at high vapor and high
liquid loads.
sAll the new products have
been integrated into one con-
sistent product portfolio with the
already well-introduced structured
packing and the tray technology of
Metawa Tray, a company which
was acquired by Sulzer Chemtech
in 1987. The portfolio is the result
of the combination of the best of
all these innovative technologies –
the classical Sulzer Chemtech,
Metawa, Nutter and Shell Global
Solutions products (Fig. 1s
) com-
plement each other into a full
range mass transfer portfolio with
minimal overlap.
CONVENTIONAL TRAYS
A conventional tray has one or
more downcomers for liquid trans-
port to the tray below and an active
area where vapor and liquid come
into contact. This active area can
be equipped with a wide choice of
bubbling devices. In today’s indus-
try, the devices used are predomi-
nantly simple sieve holes, moving
and fixed valves, depending on the
required operating range.
After an evaluation involving in-
dustrial acceptance, technical per-
formance, references and price,
Sulzer Chemtech chose the rectan-
gular Nutter BDH Float Valve™
(Fig. 2s
) as its standard moving
and Nutter V-Grid™ as its stan-
dard fixed valve. The valve portfo-
lio is completed with the Metawa
Snap-in™ valve, predominantly
used for Shell trays, a robust caged
round valve as well as a standard
round valve, mainly used for
replacement services for non-
Sulzer Chemtech trays. Further-
more, the Metawa Lip-Slot™ con-
nection (Fig. 3s
) was chosen as the
standard connection between the
horizontal tray panels.
16 S U L Z E R T E C H N I C A L R E V I E W 4 / 2 0 0 0 3974
With the acquisition of Nutter Engineering (1998) and the strategic alliance
with Shell Global Solutions (2000), Sulzer Chemtech completed its product
portfolio of mass transfer components. Nutter Engineering has brought in its
range of random packing as well as its tray technology with a competitive set
of bubbling devices for fractionation trays. The Shell mass transfer
technology package contains a complete line of high-performance trays.
Alliance of Technologies:
The Right Tray for
any Application
MARIO ROZA
DALE NUTTER
SULZER CHEMTECH
2s
A Float Valve with lateral vapor
release and streamlined liquid flow;
the absence of valve rotation and
wide legs reduce wear.
06002569-4

2. HIGH-PERFORMANCE TRAYS
Modifications to the standard
bubbling devices can give higher
vapor side tray capacity. An exam-
ple of such a device is the Mini V-
Grid MVG™ (Fig. 4s
). The Sulzer
Chemtech VortexTray™, MVGT™
and the Shell Calming Section™
and HiFi™ trays (Fig. 5s
) create
higher capacity by eliminating the
downcomer sealing area. Addition-
al to the optimized downcomer con-
figuration it is possible to install
de-entrainment devices above the
active area. These devices capture
the liquid entrained in the vapor
phase at high vapor velocities and
transport it to the downcomers.
The Shell ConSep™ tray is an
example of such a tray.
A CONSISTENT PORTFOLIO
One difficulty of Chemtech’s wide
variety of mass transfer products
is to give them all a consistent
application range. In this range,
they should be most attractive
from the commercial and technical
point of view. Sulzer Chemtech has
chosen to position them in an
application matrix arranged by
operating pressure and specific liq-
uid load (Fig. 6s
). In this matrix, all
tray types, and also structured
packing, can be positioned.
For low pressure applications,
mainly random and structured
packing are applied. The choice of
internals (trays, random or struc-
tured packing) strongly depends
on the application-related process
requirements and is not subject of
this article.
ATMOSPHERIC TO
INTERMEDIATE PRESSURE
Most towers operating under pres-
sures below 6 bar are limited by
their vapor-side capacity. In order
to increase the capacity of a valve
tray here, Sulzer Chemtech can
equip the active area with Nutter
MVG fixed valves. The reduced
entrainment of liquid to the tray
above these bubbling devices gives
10–15% capacity increase. Once
the maximum capacity with these
devices and conventional down-
comers has been reached, the
S U L Z E R T E C H N I C A L R E V I E W 4 / 2 0 0 0 17
SHELL GLOBAL SOLUTIONS
Shell Global Solutions is an international technology business that
delivers integrated services that add to their customers’ bottom
lines. Working primarily in the oil, gas and process industries, they
give a competitive edge by helping to optimize plant and process
performance, formulate and develop products, and manage opera-
tional safety and environmental challenges more effectively.
The alliance with Sulzer Chemtech covers technologies for high-
performance trays, associated internals and phase separation
equipment.
3s
The Metawa
Lip-Slot allows
fast and easy
installation.
0600 2546-3

3. 4s
MVG Mini V-Grid fixed valve (right)
compared with sieve holes. MVG has a
streamlined liquid flow and lateral vapor
release. It gives the highest proven tray
efficiency/capacity profile while having
low pressure drop and good turn-down
capability.
18 S U L Z E R T E C H N I C A L R E V I E W 4 / 2 0 0 0
NUTTER ENGINEERING
Since Earl Nutter developed the first modern valve tray in 1945, Nut-
ter Engineering continuously developed new cost-effective tray
designs and introduced them to industry with commercial-scale inde-
pendent tests. Developed in the 70s, self-retained Float Valve™ and
V-Grid™ fixed-valve trays set industry performance and mainte-
nance standards. Independent testing in 1998 proved the superior
performance of the optimized Nutter Mini V-Grid MVG fixed-valve
tray.
Sulzer acquired the innovative Nutter tray and Nutter Ring™ ran-
dom packing technology that same year to complete their mass trans-
fer component products portfolio.
downcomer configuration has to be
optimized. In a first step, down-
comers are truncated as on the
Nutter MVGT. The area under the
downcomers can be used as active
area, giving this tray 5–10% capac-
ity increase.
Sulzer Chemtech VortexTray, Shell
Calming Section™ trays and Shell
Calming Section Plus trays have
an optimized number of small
truncated downcomers, giving a
further 10–15% capacity increase
compared to the MVGT tray. The
highest capacity can be reached
with the Shell ConSep trays.
HIGH-PRESSURE SOLUTIONS
Most high-pressure applications
can also be associated with a high
specific liquid load in the column.
They are in most cases limited by
their liquid-side capacity. This
means that trays used for these
towers have to be optimized with
respect to their downcomers which
transport the liquid to the tray
below. Due to the high vapor den-
sities and low liquid densities for
high-pressure operating condi-
tions, special attention must also
be given to the vapor disengage-
ment in downcomers. This be-
comes more difficult with increas-
ing ratio between vapor and liquid
density.
Traditionally sieve and valve trays
are used for these operating condi-
tions; the MVG fixed valves can
give a 5–10% capacity increase.
Additional 5–10% can be reached
with special downcomer configura-
tions; in a first step with the Sulz-
er Chemtech VortexTray with its
special downcomer baffle, promot-
ing vapor disengagement. The
Shell HiFi and HiFi Plus trays
with their slotted downcomer
troughs can further increase tower
capacity by 10–15%.
THE GLYCOL EXCEPTION
An exception to the rule of high
pressure and high liquid load are
glycol contactors. They are used to
reduce the water content of natur-
al and fuel gas streams. They usu-
ally run at pressures between 50
and 100 bar. The liquid load in
these towers is very low. Until the
end of the seventies, bubble cap
and floating valve trays were used
for these applications. Since then,
many towers have been revamped
with Mellapak™ structured pack-
ing, which is particularly suited for

4. these conditions – capacity in-
creases of 80–100% could be
reached in many cases.
MellapakPlus™ structured pack-
ing lead to a further increase by
20–30%. In order to reach these
capacity levels, MellapakPlus and
its distributor have been combined
with a Shell Mistmat and Swirl-
deck™ combination to prevent the
loss of glycol over the top of the col-
umn. Ultimate capacity is reached
with Shell Swirl Tube™ trays.
These trays, which have a co-cur-
rent contacting space for vapor and
liquid, give a further 30–40% ca-
pacity increase.
PERFORMANCE WITH
EXPERIENCE
The alliance of Shell Global Solu-
tions’ technology and the technolo-
gy from the companies that have
been integrated into Sulzer Chem-
tech provides a complete range of
solutions with recognized benefits
for the customers. These highly
dependable mass transfer prod-
ucts are the result of profound
operational and design experience
– and will be the basis for further
innovations. Ω
F O R M O R E D E T A I L S
Sulzer Chemtech AG
Mario Roza
Postfach 65
CH-8404 Winterthur
Switzerland
Telephone +41 (0)52-262 60 08
Fax +41 (0)52-262 00 67
E-mail mario.roza@sulzer.com
5s
Shell HiFi trays are designed to handle large liquid loads. Their design
maximizes downcomer capacity while maintaining a high active area for vapor.
6s
The Application matrix; arranged by application range going downwards
in the table leads to a product with, if the design is optimized, a higher capacity
for a given tower diameter.
S U L Z E R T E C H N I C A L R E V I E W 4 / 2 0 0 0 19
Increasing
capacity
Atmospheric to
intermediate pressure,
low and intermediate
liquid load
Conventional tray
MVG tray
MVGT tray
Calming Section tray,
VortexTray
Calming Section
Plus tray
ConSep tray
High liquid load,
high pressure
Conventional tray
MVG (T) tray
Calming Section tray,
VortexTray
HiFi tray
HiFi Plus tray
ConSep tray
Glycol
(low liquid load,
high pressure)
Conventional tray
Mellapak + Mistmat
MellapakPlus +
Mistmat + Swirldeck
Swirl Tube tray
Low to atmospheric
pressure,
low and intermediate
liquid load
Conventional trays,
Nutter Ring
Mellapak
MellapakPlus
0600 2569-3