Chemical Engineering March 2019 - 7

Chementator
Process intensification for carbon capture could
reduce costs
I
n conventional solvent-based
carbon-capture systems,
CO2-rich exhaust gas contacts
gravity-driven solvents
in a vertical packed-bed column.
A novel approach developed by
Carbon Clean Solutions USA Inc.
(CCSUS; Cumming, Ga.; www.
carboncleansolutions.com)
employs
centrifugal force from rotating
horizontal packed beds to effect
the gas-to-liquid contact. The
higher g-forces allowed by the rotation
improve mass transfer and
enable smaller units to be used.
Smaller units would lower capital costs
compared to traditional carbon capture. The
system has the potential to reduce the levelized
CO2-capture cost to the U.S. Dept. of
Energy (DOE) target of $30/ton or less.
Under a $2.9-million cooperative agreement
from the DOE's National Energy Technology
Laboratory, GTI (Des Plaines, Ill.;
www.gti.energy)
Rotation
Liquid
outlet
is
the
prime
contractor
leading the effort with CCSUS to scale up
this process-intensification approach from
laboratory scale size to a larger, integrated
carbon-capture system capable of removing
1 ton/d CO2 from power-plant fluegas.
The novel carbon-capture approach, known
as ROTA-CAP technology, is designed such
that CCS's intensified solvents are pumped
into the center of the rotating cylinder, and the
centrifugal force from the rotation pushes the
liquid outward through the packed-bed gasliquid
contactor (diagram). The CO2-containing
fluegas flows from the exterior of the cylinder,
against the flow of solvent.
" A key feature of ROTA-CAP is its use of
more highly concentrated solvents than those
used in conventional carbon capture, " says
David Bahr, CCSUS technology manager,
and that can reduce the energy required for
regeneration of the CO2. Although the overall
energy savings are partially offset by the
rotational energy required in the packed-bed
cylinders, validation tests indicate up to 45%
energy savings compared to conventional
monoethanolamine (MEA) units.
GTI and CCSUS are now designing the
larger-scale system, and anticipate completing
construction by mid-2019. After
laboratory testing at GTI headquarters, the
assembly will be moved to the National
Carbon Capture Center in Wilsonville,
Ala. for long-term testing. " While the current
project is focused on capturing CO2
from fluegas at coal- and natural-gas-fired
power plants, the rotating packed-bed intensification
approach could be applied to
other industrial operations involving gasliquid
contact, " notes GTI technology manager
Osman Akpolat.
Gas inlet
Carbon Clean Solutions
Edited by:
Gerald Ondrey
ANG FUELING STATION
Gas outlet
Liquid
inlet
Gas outlet
Ingevity (North Charleston,
S.C.; www.ingevity.com)
has completed construction
of a fueling station for lowpressure
adsorbed natural
gas (ANG) at its headquarters
in North Charleston,
S.C. The fueling station will
supply natural gas to ANG
bi-fuel vehicles outfitted with
storage cylinders containing
Ingevity's Nuchar FuelSorb
activated carbon monoliths.
Bi-fuel vehicles have internal
combustion engines that can
operate on either natural gas
or gasoline. ANG technology
is made possible by Ingevity's
activated carbon, which
reduces the storage pressure
of natural gas without
sacrificing the volume of gas
stored through an adsorption
process. For more information,
see Chem. Eng., August
2017, p. 10.
NITROGEN FIXATION
A team from South China
University of Technology
(Guangzhou, China; https//
en.scut.edu.cn), led by professor
Haihui Wang, has
discovered that black phosphorus
- phosphorus in its
lowest reactivity, nontoxic
form - is an excellent catalyst
for the electro-reduction
of nitrogen to ammonia. The
team found that the zigzag
(Continues on p. 8)
Mechanical CO2 sequestration improves algae production
A
new, mechanical method
for
sequestration of
carbon
dioxide into water was
evaluated at the University
of Texas' (Austin; www.utexas.edu)
Bioproducts and Bioenergy Analytical
Service Center and has revealed
a pathway to economically improve
algae growth for production of oils.
" Existing sequestration technology
generally uses some type of sparger
to dissolve CO2 in water and make it
available to algae. Much of the gas
is not dissolved and escapes back
into the atmosphere. Our technology
results in a supersaturated CO2-water
environment where CO2 is more
available to algae, resulting in a 95%
increase in algae growth, " says Gregory
Borsinger, one of the inventors of
the technology.
The new system employs a rotorstator
device that is operated under
conditions that are thought to induce
cavitation, which results in the
supersaturation of gases into liquids.
The highly saturated CO2 solution
creates an environment of maximized
photosynthetic productivity
for algae production - in laboratory
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
MARCH 2019
trials, the CO2 saturated in the media
was consumed for algae production
in just 24 hours.
According to Borsinger, the team
from the University of Texas has observed
unprecedented
increases
in
algae growth using this new technology
when compared to other CO2delivery
mechanisms. Additionally, the
technology was applied to algae oil
harvesting and demonstrated cell lysing
of over 80%. Currently, the technology
has been demonstrated in the laboratory,
and the developers are actively
working toward commercialization.
7
http://www.ingevity.com http://www.carboncleansolutions.com http://www.gti.energy http://en.scut.edu.cn http://www.utexas.edu http://WWW.CHEMENGONLINE.COM
Chemical Engineering March 2019

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