Chemical Engineering April 2019 - 23

solids or those tending to foam,
degas or to flash.
The company's Durapack structured
packing in borosilicate glass
3.3 is suitable for corrosion-resistant
glass 3.3 or glass-lined steel columns,
as it has the same corrosion
resistance as the glass column and
keeps its thermal stability at higher
temperatures compared to polymers.
Borosilicate glass 3.3 is nonporous,
which substantially cuts
erosion and corrosion compared to
equivalent ceramic packing.
And, towers that have a side cut,
but are thermally inefficient, says
GTC's Fleming, may be good candidates
for
dividing-wall
column
technology.
" Many distillation columns
have a top and bottom product,
as well as a side-draw product,
but with this comes a lot of thermal
inefficiency. Dividing-wall column
technology - where you revamp
the traditional column - is one way
to increase capacity while reducing
energy consumption or reducing the
yield impurity of the products, " he
says (Figure 5).
The dividing-wall column separates
a multi-component feed into
three or more purified streams within
a single tower, eliminating the need
for a second column. The design
uses a vertical wall to divide the middle
of the column into two sections.
The feed is sent to one side of the
column, called the pre-fractionation
section. There, the light components
travel up the column, where they are
purified, while the heavy components
travel down the column. The
liquid flow from the column's top and
the vapor flow from the bottom are
routed to their respective sides of the
dividing wall.
From the opposite side of the wall,
the side product is removed from the
area where the middle-boiling components
are most concentrated. This
arrangement is capable of producing
a much purer middle product than
a conventional side-draw column of
the same duty, and at higher flowrate.
" The conversion to a dividing-wall
column is investigated when you're
looking at making significant improvements
you couldn't do otherwise
within the constraints of a traditional
tower, but if you can convert to
dividing-wall technology, you will see
significant decrease in energy consumption, "
he says. " Generally, there
is a 25 to 30% reduction in overall
energy consumption for a given
throughput, dramatically improved
yield and purity of products and often
an increase in throughput, as well. "
He adds that there is also opportunity
to use a dividing-wall column
to replace a traditional two-tower sequence.
" You can use dividing-wall
columns to perform the same operation
and produce the same products,
but you're doing it in one physical
tower in comparison to a two-tower
scheme. In the grassroots realm, a
substantial reduction in capital expenditures
can be achieved with
dividing-wall column technology. " n
Joy LePree
HTRI's multimillion-dollar
facility provides a controlled
testing environment with
eleven test units.
Is Your Plant Output Limited by Heat Exchangers?
HTRI has the knowledge and
tools to thoroughly examine your
heat exchanger problems.
Our Proprietary Contracts group
* troubleshoots the performance of
heat exchangers
* tests proprietary heat transfer equipment
* studies two-phase process phenomena
* performs hydrocarbon fouling testing
of crude oil and petroleum products
* reviews thermal designs
* evaluates the flow distribution for
air coolers
Contact us at contracts@htri.net
to learn how we can help solve your
heat exchanger problems.
www.htri.net
When you
need accurate
heat exchanger
performance,
you can count
on HTRI.
For details visit adlinks.chemengonline.com/73853-15
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
APRIL 2019
23
http://www.htri.net http://adlinks.chemengonline.com/73853-15 http://WWW.CHEMENGONLINE.COM
Chemical Engineering April 2019

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