The National Carbon Capture Center (NCCC) is excited to announce that EPRI is coming to the NCCC to test another promising carbon management technology.
EPRI and a research team, including Pacific Northwest National Laboratory (PNNL), RTI International (RTI) and the NCCC, recently began engineering-scale testing in the NCCC’s Pilot Solvent Test Unit (PSTU) of a water-lean solvent for post-combustion carbon capture.
“The National Carbon Capture Center plays a crucial role in the development and scale-up process of this water-lean solvent through real-world testing using the PSTU,” stated Tony Wu, NCCC project manager. “This represents a significant step forward in technological progression, demonstrating its performance on an engineering scale with realistic flue gas and operating conditions. The lessons learned from the NCCC’s test could pave the way for continuous technology improvement and scale-up toward commercialization at a lower cost.”
A brief history
With a proven track record, solvent-based carbon capture is one of the most ‘established’ carbon capture technologies and is already effectively optimized throughout the energy industry.
Solvents are specifically formulated chemicals that absorb carbon dioxide (CO2) from industry flue gases. The captured CO2 is chemically bound to the solvent, and once the solvent is saturated with CO2, it is heated to release the captured CO2 in a process called regeneration, where the solvent is then recycled back into the carbon capture system for reuse.
During the past few years, PNNL has been refining water-lean solvent classes and optimizing any physical and thermodynamic properties that limit its performance. PNNL’s solvent, N-(2-ethoxyethyl)-3-morpholinopropan-1-amine (EEMPA), has been tested at the lab and bench scale at RTI, confirming its potential for good thermal performance. EPRI has been working closely with the Carbon Capture Simulation for Industry Impact (CCSI2)* project to develop a structured test plan using a sequential design of experiments.
Testing begins
Several modifications to the NCCC’s PSTU were completed to support this test. The planned six-month test campaign will use coal- and natural gas-derived flue gas to verify EEMPA’s performance at the ~0.5 MWe-equivalent scale.
“The NCCC has been very helpful in onboarding and running the test. The engineers and staff have guided us in understanding the PSTU’s capabilities and worked with us to make important modifications needed to accommodate EEMPA,” said Joseph Swisher, Ph.D., Laboratory Fellow, EPRI. “Given their experience operating tests on new solvents, we hope to execute an ambitious test plan.”
Team objectives
The project team aims to prove the EEMPA solvent’s favorable performance characteristics while identifying and quantifying the potential to lower the cost of CO2 capture in a power plant deployment. Additionally, research data collected from this testing will support the design of further testing of EEMPA at a larger scale.
“Most advanced solvents contain 50 to 70% water, requiring excessive energy to boil off during solvent regeneration. PNNL’s unique water-lean solvent contains less than 5% water, significantly reducing such energy requirements,” expressed David Heldebrant, PhD, a laboratory fellow at PNNL. “Our solvent was designed to be a drop-in replacement that can work with conventional equipment designed for an aqueous system with minimum modifications.”
A promising future
The opportunities for EEMPA moving forward are quite promising. EEMPA can be regenerated at lower temperatures than most other solvents. The solvent exhibits a relatively low viscosity gain upon absorption of CO2 and water and does not require a diluent to maintain acceptable flow properties. Finally, EEMPA shows chemical and thermal stability and compatibility with polymer materials, meaning the process uses plastics for the absorber packing, potentially resulting in important capital cost savings.
EEMPA’s challenges are reducing production costs, demonstrating large-scale production, and carefully controlling the water balance process. However, if successfully developed, this technology could help lower carbon capture costs for widespread deployment to achieve a net-zero target.
Like any solvent test at NCCC, real-world operation experiences and immense data collected through the test campaigns will help technology developers further improve the solvent formulas, refine the capture process and update their model for performance prediction. All these are essential for the technology to scale up towards commercialization.
Managed and operated by Southern Company and funded by the U.S. Department of Energy (DOE) and multiple sponsors, the NCCC is steadfast in its commitment to advancing viable and innovative carbon management technologies.