Post-combustion CO2 control systems separate CO2 from the flue gas produced by conventional coal combustion in air. The flue gas is at atmospheric pressure and has a CO2 concentration of 10-15 volume percent.
Capturing CO2 under these conditions is challenging because:
- The low pressure and dilute concentration dictate a high total volume of gas to be treated.
- Trace impurities in the flue gas tend to reduce the effectiveness of the CO2 separation processes.
- Compressing captured CO2 from atmospheric pressure to pipeline pressure (1,200-2,200 pounds per square inch) represents a large parasitic energy load.
NETL's post-combustion CO2 control technology R&D program includes projects directed at the use of solvents, solid sorbents, and membranes. Amine-based solvent systems are in commercial use for scrubbing CO2 from industrial flue gases and process gases. However, solvents have not been used to remove large volumes of CO2 as would be encountered in a pulverized coal-fired utility boiler flue gas. Solid sorbents can be used to capture CO2 from flue gas through chemical adsorption, physical adsorption, or a combination of the two. Possible configurations for contacting the flue gas with solid sorbents include fixed, moving, and fluidized beds. Membrane-based capture uses permeable or semi-permeable materials that allow for the selective transport/separation of CO2 from flue gas.
NETL funds multiple post-combustion CO2 emission control projects employing each of these three approaches. These R&D efforts are performed by external research organizations and academic institutions and by NETL's Office of Research and Development (ORD). The In-House Carbon Capture R&D webpage provides information regarding NETL’s internal R&D. Each of the sections below lists on-going and completed external projects and provides a link for more information on each project.
Carbon Capture Project Location Map (Best viewed by IE 9 or later, Firefox, or Google Chrome)