Chemical Engineering March 2019 - 10

are major byproducts of dairy
processing and represent a
key challenge for the dairy industry
due to a lack of reliability
in current disposal routes,
and represent a sustainability
bottleneck for the expansion
of milk production in Europe.
In an effort to valorize such
waste, a new E.U.-funded
project - dubbed AgriChemWhey
- started last month.
AgriChemWhey is testing and
proving the techno-economic
viability of converting agriculture
and agri-food waste
into sustainable lactic acid at
a first-of-its-kind biorefinery.
The industrial-scale biorefinery
is to be located in the South
East region of Ireland, and will
have the capacity to valorize
over 25,000 metric tons per
year (100% dry matter) of excess
WP and DLP.
Representing the first major
industrial venture to convert
residues from food processing,
the flagship plant in Ireland
will scale-up a unique fermentation
processes of WP/
DLP-to-lactic acid (LA) by reducing
the fermentation time
to a 12-h process, optimizing
the upstream processes of
DLP and WP and optimizing
the downstream steps for
simplified LA purification at
industrial scale. The process
was developed by Agrichem(Continues
on p. 11)
Gas analysis made easier for high-dust areas
A
co l l abor a t i on
between Servomex
(Surrey,
U.K.; www.servomex.com)
and FLO2R
(Hadsund,
Denmark;
www.flo2r.com) has resulted
in the industry's
first laser-based gasanalysis
system for use
in high-dust environments.
Tunable diode
laser (TDL) technology
provides a much more
rapid response than
conventional
extractive
systems for gas analysis,
but it historically has been infeasible for use
in applications where dust is present, since
TDL systems rely on light visibility, and the
presence of dust can inhibit laser transmittance,
says Karsten Brink Floor, managing
director of FLO2R. The new Hybrid 600 system
(diagram) incorporates optics that minimize
light loss in dusty conditions and also a
built-in air knife that protects optic elements
from process gases.
Furthermore, dust-heavy applications typically
require large ducts, and installation of
laser systems is usually limited to smaller duct
sizes, but Floor explains that the new Hybrid
600 system uses a unique single-flange
mounting configuration that enables its setup
in ducts of any size, in applications with dust
loads as high as 200 g/m3. Floor envisions
that the Hybrid 600 system will fulfill two critical
gas-analysis needs - safety interlocking
applications and emissions control.
Commercial trials of the new system were
recently completed at the Aalborg Portland
cement plant in Denmark, where Hybrid
600 technology was used to monitor carbon
monoxide levels on two kiln lines to ensure
that excessive CO volumes would not
lead to explosive conditions, based on the
plant's safety interlocking limits. Key to ensuring
a safe installation, according to Floor,
was to determine the optimal measuring
point for CO, which, in this case, was as
close as possible to the CO's origin in the
pre-heater system, where dust loads may
vary between 75 and 200 g/m3. Floor expects
to roll out the technology into waste
incinerators, power plants and clay-burning
kilns in the coming months.
A new, more comprehensive electronegativity scale
T
10
he electronegativity of atoms
is one of the most well-known
parameters for explaining why
chemical reactions occur.
Now, Martin Rahm, assistant professor
of physical chemistry at Chalmers
University of Technology (Gothenburg,
Sweden; www.chalmers.
se), has redefined the concept with
a new, more comprehensive scale.
His work, undertaken with colleagues
Tao Zeng at Carleton University (Ottawa,
Ont., Canada; www.carleton.
ca) and Roald Hoffmann at Cornell
University (Ithaca, N.Y.; www.cornell.
edu), was published in a recent issue
of J. Am. Chem. Soc.
Numerous electronegativity scales
have been developed since the concept
was first proposed by Swedish
chemist Jöns Jacob Berzelius in
the 19th century, but most of these
scales only cover parts of the periodic
table, typically omitting various heavy
or heaviest elements. The new scale
covers elements 1 to 96 - the most
comprehensive to date.
" The new definition is the average
binding energy of the outermost
and weakest-bound electrons
- commonly known as the valence
electrons, " explains Rahm. " We derived
these values by combining experimental
photoionization data with
quantum mechanical calculations. By
and large, most elements relate to
each other in the same way as in earlier
scales. But the new definition has
also led to some interesting changes
where atoms have switched places in
the order of electronegativity. Additionally,
for some elements, this is the
first time their electronegativity has
been calculated, " says Rahm.
For example, compared to earlier
scales, manganese and zinc have
both been moved in the ranking,
relative to elements closest to them
in the periodic table. Fluorine is still
the most electronegative element in
the new scale, but it is 1.3 eV less
electronegative than helium, which
helps to explain the non-existence of
helium fluorides.
One challenge with electronegativity
as a concept is that it is sometimes
unable to predict chemical reactivity or
the polarity of chemical bonds. A further
advantage of the new definition is
how it fits into a wider framework that
can help explain what happens when
chemical reactions are not controlled
by electronegativity, says Rahm.
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
MARCH 2019
Analysis cell
TDL analyzer
Air knife -
perpendicular purge
Sample probe
Heated
sample
path
FLO2R
http://www.ser http://www.vomex.com http://www.flo2r.com http://www.chalmers http://www.carleton http://www.cornell http://WWW.CHEMENGONLINE.COM
Chemical Engineering March 2019

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