Chemical Engineering July 2016 - 9

Chementator
Fuel-cell-based carbon capture system can
augment power generation
P
ost-combustion
carbon-capture
processes that
are based on
Anode exhaust contains
water and CO2 produced
at anode. CO2 will be
consumed by cathode
reaction
adsorption of CO2 by
amine compounds reduce
the power output
of coal- and naturalgas-fired
power plants
largely due to the energy
required to regenerate
the CO2 from the adsorbent
material. In another
approach, carbonate
fuel cells can be used
to separate CO2 from
power plant exhaust
streams while generating
electricity and boosting
the overall power
output of the plant.
A new development
partnership between ExxonMobil Corp. (Dallas,
Tex.; www.exxonmobil.com) and Fuel
Cell Energy Inc. (FCE; Danbury, Conn.; www.
fuelcellenergy.com) has the goal of utilizing
FCE's carbonate fuel cell technology so it can
be used to separate and concentrate CO2
from the exhaust gas of a commercial-scale
natural-gas power plant.
Carbonate fuel cells produce hydrogen
Air
standard system
CO2
compression
CO2
CO2
separation
Air
preheat
Fossil plant or
industrial flue gas
with CO2
CO2 needed for cathode
reaction is provided by
external source. Cathode
reaction will transfer CO2 to
anode for removal.
Water
recovery
Power
Anode
exhaust
cooling
Fuel cell
anodes
Fuel cell
cathodes
Fuel Recovered
water
DFC-carbon capture system
from natural gas and biogas, and then use
the H2 to generate electricity and water. In
a carbonate fuel cell, carbonate ions are
formed (along with electrons) at the anode,
and these ions complete the electrical circuit
across the electrolyte layer of the fuel
cell stack (see figure). Since such fuel cells
require CO2 to form carbonate ions, powerplant
exhaust gas - containing 5% CO2 in
the case of a natural gas plant - can be
used as a CO2 source, and the fuel cell then
becomes a means of separating and concentrating
CO2 from the exhaust, explains
Tony Leo, vice president of applications and
technology development for FCE. " There's
an internal CO2 cycle within the carbonate
fuel cell, which can be co-opted to separate
CO2 for carbon capture without the need for
a regeneration step, as is the case in aminebased
carbon capture, " he says. As an
added benefit, 70% of the oxides of nitrogen
(NOx) compounds are reduced to N2 in the
electrochemical cell, Leo notes.
The ExxonMobil-FCE project for developing
carbonate fuel cells for carbon capture
in natural-gas plants joins an ongoing U.S.
Dept. of Energy funded project to adapt FCE
carbon capture technology for use in coalfired
power plants.
A 3-D printed polymer with enzymes
turns methane to methanol
S
cientists from Lawrence Livermore
National Laboratory (LLNL; Livermore,
Calif.; www.llnl.gov) have
combined biology and 3-D printing
to create the first reactor that can continuously
produce methanol from methane at
room temperature and pressure. The team
removed enzymes from methanotrophs -
bacteria that metabolize methane - and
mixed them with polymers that were printed
or molded into innovative reactors. " Remarkably,
the enzymes retain up to 100% activity
in the polymer, " according to Sarah Baker,
LLNL chemist and project lead. " The printed
enzyme-embedded polymer is highly flexible
for future development and should be useful
in a wide range of applications, especially
those involving gas-liquid reactions. "
The research, which could lead to more
efficient conversion of methane-to-energy
production, was described in a recent issue
of Nature Communications.
Note: For more information, circle the 56-digit number on p. 62, or use the website designation.
ChemiCal engineering www.Chemengonline.Com July 2016
Air
preheat
Power
Fuel cell
anodes
Fuel cell
cathodes
Fuel
Water
Fuel &
water
preheat
Making More ara
Arcadia Biosciences Inc.
(Davis, Calif.; www.arcadiabio.com)
and Dupont
Pioneer (Des Moines, Iowa;
www.pioneer.com) recently
completed field-trial validation
for new safflower plants
that produce high levels of
arachidonic acid (ARA) oil, a
high-value, specialty nutritional
oil. The field validation
is a key milestone for Arcadia
and DuPont Pioneer in
their pursuit of a new plantbased
and cost-effective
source of high-ARA oil.
ARA is an omega-6 fatty
acid that, along with certain
omega-3 fatty acids, plays
a critical role in neural and
visual development of infants.
It is one of the most
abundant fatty acids in the
brain, and neurological
health is reliant upon sufficient
levels of ARA. The
oil appears as a functional
ingredient in many infant
nutrition products, and has
been shown to provide developmental
benefits similar
to breastfeeding. High-ARA
safflower plants will offer a
more efficient source for the
ingredient, and will improve
manufacturing economics
and encourage wider use
of ARA. Arcadia's ARA safflower
oil is in the late stages
of product development.
express saMpling
To determine the levels of
polycyclic aromatic hydrocarbons
(PAHs) in soil and
sediment, one must first extract
the compounds from
a sample - a step that can
take up to 16 h and require
large amounts of hazardous
solvents. Newer, hightemperature
techniques are
faster and need much less
solvent, but they require expensive
equipment. A costeffective
alternative has been
devised by Francesc A. Es(Continues
on p. 10)
9
Edited by:
Gerald Ondrey

http://www.arca http://www.diabio.com http://www.pioneer.com http://www.exxonmobil.com http://www.fuelcellenergy.com http://www.llnl.gov http://www.Chemengonline.Com

Chemical Engineering July 2016

Table of Contents for the Digital Edition of Chemical Engineering July 2016