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CO2 Capture and Regeneration at Low Temperatures

Research Triangle Institute (RTI)
Novel Non-Aqueous CO2 Solvents and Capture Process with Substantially Reduced Energy Penalties
Graphic of RTI's technology
Program: 
ARPA-E Award: 
$2,475,501
Location: 
Research Triangle Park, NC
Project Term: 
07/01/2010 to 09/30/2013
Project Status: 
ALUMNI
Technical Categories: 
Critical Need: 

Coal-fired power plants provide nearly 50% of all electricity in the U.S. While coal is a cheap and abundant natural resource, its continued use contributes to rising carbon dioxide (CO2) levels in the atmosphere. Capturing and storing this CO2 would reduce atmospheric greenhouse gas levels while allowing power plants to continue using inexpensive coal. Carbon capture and storage represents a significant cost to power plants that must retrofit their existing facilities to accommodate new technologies. Reducing these costs is the primary objective of the IMPACCT program.

Project Innovation + Advantages: 

Research Triangle Institute (RTI) is developing a solvent and process that could significantly reduce the temperature associated with regenerating solvent and CO2 captured from the exhaust gas of coal-fired power plants. Traditional CO2 removal processes using water-based solvents require significant amount of steam from power plants in order to regenerate the solvent so it can be reused after each reaction. RTI's solvents can be better at absorbing CO2 than many water-based solvents, and are regenerated at lower temperatures using less steam. Thus, industrial heat that is normally too cool to re-use can be deployed for regeneration, rather than using high-value steam. This saves the power plant money, which results in increased cost savings for consumers.

Potential Impact: 

If successful, RTI's non-water-based CO2 solvents would substantially reduce the cost of carbon capture to coal-fired power plants. This will limit the costs that are passed onto consumers and limit the amount of greenhouse gases released into the atmosphere.

Security: 

Enabling continued use of domestic coal for electricity generation will preserve the stability of the electric grid.

Environment: 

Carbon capture technology could prevent more than 800 million tons of CO2 from being emitted into the atmosphere each year.

Economy: 

Enabling cost-effective carbon capture systems could accelerate their adoption at existing power plants.

Innovation Update: 

(As of December 2016) 
The RTI International team has demonstrated significant potential to lower the cost of carbon capture in coal-fired power plants compared with the incumbent amine treatment process. RTI developed a non-aqueous solvent (NAS) that could potentially reduce the energy required for carbon capture by 20-30%. Following completion of its ARPA-E project, RTI initiated a follow-on collaboration with Linde LLC and was awarded funding by the National Energy Technology Laboratory (NETL) to refine the NAS solvents and test them in a larger facility. Since then, hundreds of hours of bench-scale testing have been completed, and the results indicate that the NAS technology can reduce required capture energy to less than two gigajoules per ton of carbon dioxide (CO2), consistent with RTI’s initial projections of a 20-30% reduction in energy required compared to state-of-the-art.  

Following that project, RTI received additional federal funding from NETL to scale the RTI NAS process up to a 60 kW facility in collaboration with SINTEF, a Norwegian research company. The SINTEF facility is being outfitted with a multiburner that allows, for the first time, testing of NAS in coal-derived flue gas. The results will be used to create a more accurate projection of the CO2 capture cost for NAS.

The RTI team screened a large number of solvents to identify candidates with: (1) low water solubility to avoid excess water uptake; (2) low vapor pressure to reduce solvent losses; (3) low heat capacity to minimize the energy required to regenerate the solvent; and (4) low corrosivity. RTI ultimately selected five solvents that could potentially meet the target of being regenerated at temperatures below 120 degrees Celsius, the current minimum temperature for amine solvents. After conducting long-term testing, RTI designated the most promising solvent composition NAS-2. NAS-2 was tested for 600 hours in simulated flue gas, which included contaminates such as sulfur dioxide. The team concluded that with some sulfur cleanup at power plants, the degradation rate of their solvent would be no more than 1% per 100 hours. 

For a detailed assessment of the RTI project and impact, please click here.

Contacts
ARPA-E Program Director: 
Dr. Ping Liu
Project Contact: 
Dr. Luke Coleman
Partners
BASF
Release Date: 
4/29/2010