che_february-2024 - 27

60-mm Schott
flange
60-mm Schott
flange
2 " trays
2 " spacing
2 " Packing
Packing
supports
AVN Corp.
FIGURE 7. Flexible column sections can contain
trays or packing
collection. Agitation becomes critical
at low pressure, due to liquid bumping
(vapor-liquid disengagement).
Seals between the headplate and
column, as well as the headplate
and glass vessel, are made of FFKM
perfluoroelastomeric O-rings (Kalrez,
Simrez, Markez and so on), which
are resistant to a large range of
chemicals. Some formulations can
withstand temperatures in excess of
300˚C, and provide nearly leak-free
connections even at high vacuum.
At elevated pressures, however,
other joint types should be explored.
A reboiler such as this would be
intended as the centerpiece of a
versatile distillation system that will
allow for rapid exchange of packed
or trayed sections, as well as modifications
to the number of stages,
number and location of feeds, condenser
types and inclusion (or not) of
a vacuum system, a sidestream or
an overhead decanter. The heating
bath has the capability of heating oil
up to 300˚C.
Column sections. Figure 7 shows
examples of column sections to
be used in this distillation system.
These contain Oldershaw trays, or
are open tubes used for random
or structured packing. O-ring joints
(60-mm Schott Duran O-ring joints)
allow connection to the metal headAVN
Corp.
FIGURE 8. The photo shows a joint heater for
60-mm Schott flange on a 1-in.-dia. packed and
unsilvered distillation column
part of a versatile laboratory distillation
apparatus. The glass vessel can
be heated by hot oil in its jacket or its
coil. A bottom port allows connection
to a forced-circulation system.
The glass vessel can be replaced
by an unjacketed version that would
allow for heat input by an electric
heating mantle.
The hollow headplate, which is
constructed of Hastelloy C, can be
heated with hot oil to prevent vapor
condensation on the headplate. A
magnetic-drive agitator is mounted
in the center of the headplate, which
also has connections for the column,
a thermocouple, liquid level and column
differential pressure (high lead),
forced circulation return and sample
Vent line is flexible (to allow
swing arm to move)
Jerguson gage
Organic layer
Decanter
(316 SS)
Upstream
pressure
above 1 Atm
Wire-mesh packing
plate discussed above, or to each
other. Multiple O-ring ball-joint column
ports can be used for feed,
sampling or thermocouples. These
types of joints have the advantage
(over ground-glass joints) of low
clearances, so that the entire column
does not need to be disassembled
to make a change to a
column section. They do not require
vacuum grease, which can lead to
process contamination. The joints
don't freeze together, which would
prevent disassembly, and they provide
more consistent vacuum sealing
performance. In addition, the
clamps are easy to install. In order
to prevent heat loss from the joints,
custom joint heaters have been fabricated
(Figure 8).
Normally, adiabatic operation will
be accomplished by heat tape and insulation.
However, vacuum-jacketed
column sections can also be used.
The 3D-printed tray sections, as
discussed earlier, can be used in
place of the glass sections for pressure
operations, assuming that the
other glass parts on the system will
be replaced with metal. Alternative
joint types will need to be used, such
as sanitary seals, pipe, Grayloc and
so on.
Column sizing software
Vent
Aqueous layer
Fittings (these will need to be
loosened to change angle of
swing arm)
FIGURE 9. Automatic decanters can be used for distillates with two liquid phases
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
FEBRUARY 2024
27
http://WWW.CHEMENGONLINE.COM
che_february-2024

Table of Contents for the Digital Edition of che_february-2024
