Chemical Engineering February 2012 - 12

CHEMENTATOR
A simulation demonstrates the
potential of NH3 as a power source
H
arnessing renewable energy by catalytic
dissociation and synthesis of ammonia
has shown promise for distributed power
applications, according to a team from the
Center for Energy at the University of Western
Australia (www.uwa.edu.au), led by professor
Dongke Zhang.
In the team's concept (flowsheet), solar
or geothermal energy provides the heat required
to dissociate ammonia into nitrogen
and hydrogen gases via an endothermic reaction
with a nickel catalyst. The gases are
then synthesized back into ammonia using
a ruthenium catalyst in an exothermic reaction.
The hot synthesized gas is then used
as the working fluid through a gas turbine
using the Rankine cycle.
The ammonia produced as a working fluid
is at 923K, whereas the ammonia needs to
be heated to only 723K at the process pressure
of 20 MPa for dissociation by the renewable
source.
The team chose ammonia due to its low
boiling point and a relatively low dissociation
temperature. Heating ammonia to 723K
is best done by means of a solar parabolic
trough or a solar parabolic dish. The system
has an efficiency of 25.4% producing 285 kW
of electrical power with a molar flowrate of
100 kmol/h.
The team studied a simulation using two
single reactors, one for the dissociation reaction
and the other for the synthesis reaction.
Pump
The temperature is maintained using an external
fluid that is heated by the synthesis
reaction to heat the dissociation reactor.
The team plans to develop a prototype to
confirm the predictions regarding the efficiency
and electrical power output.
Next-generation cross-coupling reactions
P
rofessor Kenichiro Itami and coworkers
at at Nagoya University (Nagoya,
Japan; synth.chem.nagoya-u.ac.jp) have
developed a new, next-generation type of
cross-coupling reaction for synthesizing
biphenyl compounds - one of the most
important backbone structures for pharmaceutical
and electronics chemicals. The
chemists have developed the first nickelcatalyzed
arylation reaction of the C-H
bond of azole compounds using phenol derivatives.
Prior to this development, such
cross-coupling reactions required aryl
halides or organometallic reagent (Ar-M)
as a coupling partner, which added several
reaction steps just to make the Ar-M;
and the catalyst was based on costly palladium.
The new approach uses readily
Heater
Turbine
Dissociation
reactor
Synthesis
reactor
Compressor
Heat exchanger
(Continued from p. 10)
Cooler
Gas-liquid
separator
north american wastewatertreatment
plant has calculated
that it saves up to 30% in its
annual $2.5-million chemicals
costs, and a Finnish municipal
plant estimates it will achieve
€15,000/yr savings in polymers
and centrifuge usage only by
keeping reject-water totalsuspended
solids lower than
1,000 mg/l, says Timo rantala,
product manager with metso's
automation business line.
Microbial oil
neste oil oyj (uusimaa; www.
nesteoil.com) has selected
neste Jacobs oy (Porvoo, both
Finland; www.nestejacobs.
com) as its main partner for a
pilot plant designed to produce
waste-based microbial oil at
its Porvoo reinery. it will be
the irst pilot plant in europe
designed to produce microbial
oil for use in manufacturing renewable
fuel from waste-based
raw materials.
The plant will be used to deavailable
phenol derivatives as a coupling
partner, and a nickel-based catalyst that
is easy to make and less expensive than
Pd-based catalysts.
The new catalytic system - Ni(cod)2/
dcype, where cod = 1,5-cyclooctadiene and
dcype = 1,2-bis(dicyclohexylphosphino)ethane
- is prepared from Ni and commercially
available dcype, and is active for the coupling
of various phenol derivatives, such as
esters, carbamates, carbonates, sulfamates,
triflates, tosylates and mesylates. By using
the C-H/C-O biaryl coupling, a series of
privileged 2-arylazoles - including biologically
active alkaloids - were synthesized.
Moreover, the researchers demonstrated the
utility of this reaction for functionalizing estrone
and quinine.
12 ChemiCal engineering www.Che.Com February 2012
velop microbial-oil-production
processes and test various raw
materials for producing microbial
oil, such as straw and other
agricultural residues, as well as
industrial waste and residues.
The plant will support neste oil's
goal of using microbial oil to produce
nexbTl renewable diesel
in the future. The €8-million facility
is due to be completed in the
second half of 2012.
The production of nexbTl
renewable diesel from microbial
oil has already succeeded at the
laboratory scale. The new pilot
plant is an important step on the
way to scaling up the technology
to commercial capability, which
is likely to be possible by 2015 at
the earliest. ❏
http://www.uwa.edu.au http://www.nesteoil.com http://www.nestejacobs http://synth.chem.nagoya-u.ac.jp http://www.Che.Com
Chemical Engineering February 2012

Table of Contents for the Digital Edition of Chemical Engineering February 2012
