Novel 3D-printed device demonstrates enhanced capture of carbon dioxide emissions

Date:
August 24, 2020
Source:
DOE/Oak Ridge National Laboratory
Summary:
Researchers have designed and additively manufactured a
first-of-its-kind aluminum device that enhances the capture of
carbon dioxide emitted from fossil fuel plants and other industrial
processes.



FULL STORY ==========================================================================
The Department of Energy's Oak Ridge National Laboratory researchers
have designed and additively manufactured a first-of-its-kind aluminum
device that enhances the capture of carbon dioxide emitted from fossil
fuel plants and other industrial processes.


========================================================================== Solutions for reducing global emissions of heat-trapping greenhouse gases
such as CO2 address the continued use of low-cost, domestic fossil fuel resources while mitigating potential climate impacts.

ORNL's device focuses on a key challenge in conventional absorption
of carbon using solvents: the process typically produces heat that can
limit its overall efficiency. By using additive manufacturing, researchers
were able to custom design a multifunctional device that greatly improves
the process efficiency by removing excess heat while keeping costs low.

Absorption, one of the most commonly used and economical methods for
capturing CO2, places a flue-gas stream from smokestacks in contact
with a solvent, such as monoethanolamine, known as MEA, or other amine solutions, that can react with the gas.

The team tested the novel circular device, which integrates a heat
exchanger with a mass-exchanging contactor, inside a 1-meter-tall
by 8-inch-wide absorption column consisting of seven commercial
stainless-steel packing elements. The 3D-printed intensified device was installed in the top half of the column between the packing elements.

Additive manufacturing made it possible to have a heat exchanger within
the column, as part of the packing elements, without disturbing the
geometry, thus maximizing the contact surface area between the gas and
liquid streams.



==========================================================================
"We call the device intensified because it enables enhanced mass transfer
(the amount of CO2 transferred from a gas to a liquid state) through
in-situ cooling," said Costas Tsouris, one of ORNL's lead researchers
on the project.

"Controlling the temperature of absorption is critical to capturing
carbon dioxide." When CO2 interacts with the solvent, it produces
heat that can diminish the capability of the solvent to react with
CO2. Reducing this localized temperature spike in the column through
cooling channels helps increase the efficiency of CO2 capture.

"Prior to the design of our 3D printed device, it was difficult to
implement a heat exchanger concept into the CO2 absorption column
because of the complex geometry of the column's packing elements. With
3D printing, the mass exchanger and heat exchanger can co-exist within
a single multifunctional, intensified device," said ORNL's Xin Sun,
the project's principal investigator.

Embedded coolant channels were added inside the packing element's
corrugated sheets to allow for heat exchange capabilities. The final
prototype measured 20.3 centimeters in diameter, 14.6 centimeters in
height, with a total fluid volume capacity of 0.6 liters. Aluminum was
chosen as the initial material for the intensified device because of
its excellent printability, high thermal conductivity, and structural
strength.

"The device can also be manufactured using other materials, such
as emerging high thermal conductivity polymers and metals. Additive manufacturing methods like 3D printing are often cost-effective over time because it takes less effort and energy to print a part versus traditional manufacturing methods," said Lonnie Love, a lead manufacturing researcher
at ORNL, who designed the intensified device.



==========================================================================
The prototype demonstrated that it was capable of substantially enhancing carbon dioxide capture with the amine solution, which was chosen because
its highly reactive to CO2. In results published in the AIChE Journal,
ORNL researchers conducted two separate experiments -- one that varied
the CO2- containing gas flow rate and one that varied the MEA solvent
flow rate. The experiments aimed to determine which operating conditions
would produce the greatest benefit to carbon capture efficiency.

Both experiments produced substantial improvements in the carbon capture
rate and demonstrated that the magnitude of the capture consistently
depended on the gas flow rates. The study also showed a peak in capture at
20% of carbon dioxide concentration, with percent of increase in capture
rate ranging from 2.2% to 15.5% depending on the operating conditions.

"The success of this 3D printed intensified device represents an
unprecedented opportunity in further enhancing carbon dioxide absorption efficiency and demonstrates proof of concept," Sun said.

Future research will focus on optimizing operating conditions and
device geometry to produce additional improvements in the carbon capture absorption process.

The work was sponsored by DOE's Office of Fossil Energy.


========================================================================== Story Source: Materials provided by
DOE/Oak_Ridge_National_Laboratory. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. Eduardo Miramontes, Ella A. Jiang, Lonnie J. Love, Canhai Lai,
Xin Sun,
Costas Tsouris. Process intensification of CO 2 absorption using
a 3D printed intensified packing device. AIChE Journal, 2020; 66
(8) DOI: 10.1002/aic.16285 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200824131809.htm

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