Chemical Engineering February 2014 - 24

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Charles Ross & Son
product life cycles, " says Peter
Rojan, deputy sales manager at
Ekato (Schopfheim, Germany; www.
ekato.de). " Modern manufacturing
processes are as complex and just as
varied as the products themselves.
It is therefore difficult for chemical
processors to develop the optimum
agitation solution themselves with
respect to process requirements, investment
and operating costs and
energy and resource efficiency. "
While modern mixers are designed
for particular process requirements
and mixing tasks, allowing
them to operate efficiently,
an integrated approach to tailor
such agitation systems to the actual
process conditions makes them
also extremely robust and reliable
so that downtime and repair costs
are also minimized, says Rojan.
" The integrated agitation solutions
go beyond the actual agitator,
and are based upon a case-by-case
analysis of the actual industrial
requirement, " he says. " They apply
state-of-the-art impellers that are
adapted for the specific mixing
task. The complete agitation systems
are carefully tailored to the
vessel geometry and are built out
of materials and components that
are individually designed to meet
maximum reliability and minimum
investment costs. "
A typical example of such a tailormade
agitation system is Ekato's
range of hydrogenation reactors
(Figure 4). " Hydrogenation processes
were traditionally limited
by mass and heat transfer. At the
same time, the hydrogen is difficult
to handle and such reactors must
be operated absolutely gas-tight at
high pressures, " he says. " At Ekato,
we developed a self-aspirating gassing
turbine, which is specifically
applied in such reactions to overcome
the mass-transfer limitation. "
Figure 5. Charles Ross & Son's SLIM
Solids Injection Technology consists of
a rotor and stator mixing arrangement,
specially designed to create negative
pressure (vacuum) behind the rotor
High-shear mixing
" Sometimes processors are using
equipment that isn't well suited to
their process, " says Ken Langhorn,
technical director with Charles
Ross & Son Co. (Hauppauge, N.Y.;
mixers.com). " That's obviously an
inefficiency in and of itself, but
often we find they are using a lowspeed
agitator, which results in a
reaction taking a long time to occur
and using more energy than is necessary.
Often, they can benefit by
having a more intense mixing arrangement
to process the product
quicker. Instead of 12 hours of slow
agitation, they can do the same
batch in 20 mininutes using something
more vigorous. "
For this reason, Langhorn says
many processes can benefit from
high-shear mixing. " The interaction
between the rotor and stator generates
a lot of shear between liquids,
which helps increase the efficiency, "
he says. " In some chemical processes,
while generating an emulsion
or dissolution, processors can
benefit from having high shear mixing
within the batch to more quickly
generate the emulsion or more
quickly dissolve the materials. "
He adds that some of the highCircle
5 on p. 60 or go to adlinks.che.com/50973-05
24 ChemiCal engineering www.Che.Com february 2014
shear mixers can directly incorporate
powders into liquids. In many
processes, that would normally
require a two-step process, so this
technology can provide a large efficiency
gain.
Ross's SLIM Solids Injection
http://www.ekato.de http://www.mixers.com http://adlinks.che.com/50973-05 http://www.Che.Com
Chemical Engineering February 2014

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