Researchers Propose On-Board Fuel Processing with Carbon Capture for Zero-GHG, Hydrogen-Fueled Combustion Engine Vehicles
|The vision of a sustainable carbon economy for transportation relies on the on-board conversion of a liquid hydrocarbon fuel with CO2 capture and recycling. Click to enlarge.|
Researchers at the Georgia Institute of Technology are exploring a conceptual strategy to capture, store and eventually recycle carbon dioxide emissions from mobile and small distributed stationary sources—such as automobiles, transportation vehicles and distributed industrial power generation applications (e.g., diesel power generators). Nearly two-thirds of global carbon emissions are created by such mobile and stationary sources.
Georgia Tech’s strategy involves using an on-board fuel processor to reform a liquid hydrocarbon fuel (fossil or synthetic) to produce hydrogen to power the vehicle or stationary source. The carbon in the original fuel is captured and stored on board in a liquid form, until it is disposed of at a refueling station.
While the researchers see the carbon then being transported and sequestered in the short term, for the longer term they propose recycling the captured carbon back into a synthetic liquid transportation fuel to complete what would become a close-loop cycle.
The Georgia Tech team has already designed a fuel processor, called CO2/H2 Active Membrane Piston (CHAMP) reactor, capable of efficiently producing hydrogen and separating and liquefying CO2 from a liquid hydrocarbon or synthetic fuel used by an internal combustion engine or fuel cell. After the carbon dioxide is separated from the hydrogen, it can then be stored in liquefied state on-board the vehicle. The researchers have filed a patent application on the device.
The fuel processor produces the hydrogen on-board the vehicle from the hydrocarbon fuel without introducing air into the process, resulting in an enriched carbon byproduct that can be captured with minimal energetic penalty. Traditional combustion systems have a combustion process that combines fuel and air—leaving the carbon dioxide emissions highly diluted and very difficult to capture.
We had to look for a system that never dilutes fuel with air because once the CO2 is diluted, it is not practical to capture it on vehicles or other small systems.—David Damm, lead author
The research, funded by NASA, the US Department of Defense NDSEG Fellowship Program and Georgia Tech’s CEO (Creating Energy Options) Program, was published in Energy Conversion and Management.
The Georgia Tech team compared the proposed system with other systems that are currently being considered, focusing on the logistic and economic challenges of adopting them on a global scale. In particular, electric vehicles could be part of a long-term solution to carbon emissions, but the team raised concerns about the limits of battery technology, including capacity and charging time.
And while liquid-based hydrogen carriers could be conveniently transported and stored using existing fuel infrastructure, the distribution of gaseous hydrogen would require the creation of a new and costly infrastructure of pipelines, tanks and filling stations.
David L. Damm and Andrei G. Federov, Conceptual study of distributed CO2 capture and the sustainable carbon economy. Energy Conversion and Management, Article in Press, Published online doi:10.1016/j.enconman.2007.11.011
GA Tech MITf Research Overview Fall 2007
US Patent Application #20070243127, Hydrogen-generating reactors and methods