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Ohio State Chemical Looping Process Advances Clean Coal Technology

The Ohio State University is leading a joint development effort to scale up chemical looping technology at the U.S. Department of Energy’s National Carbon Capture Center, operated by Southern Company in Wilsonville, Ala. Ohio State and Southern Company have signed a collaborative testing agreement to demonstrate the high pressure syngas-to-hydrogen chemical looping process. 

Chemical looping is a novel process for effectively converting carbon-based fuels to electricity, hydrogen and/or liquid fuels with near-zero carbon emissions. This process could achieve one of the lowest cost and most efficient technologies yet developed for CO2-free energy from coal. Liang-Shih Fan, Ohio State professor of chemical and biomolecular engineering and principal investigator on the project, is committed to advancing and industrializing such clean coal technology.

Construction on the pilot plant is expected to begin in May and end in late 2012 to early 2013. Fan and his colleagues plan to complete the commissioning and operation of the pilot unit during 2013. The goal of the pilot plant is to demonstrate the syngas chemical looping technology for 1,000 hours under reactive conditions. Afterward, a rigorous techno-economic analysis will be performed incorporating the pilot demonstration results to the syngas chemical looping technology and compared against traditional clean fuel conversion processes. Successful demonstration of the pilot unit, coupled with solid economic findings, will support further scale-up demonstration of the syngas chemical looping technology toward its commercialization.

The Ohio State syngas iron looping process circulates various iron oxide forms through different reaction zones. Carbon-based fuel is first oxidized to CO2, captured and sequestered, and simultaneously iron oxide is reduced to its elemental form. After the reducer, the elemental iron is oxidized by steam, producing hydrogen and an intermediate iron oxide form. The intermediate iron oxide is then burned in air to produce a more reactive iron oxide, which is circulated back to the reducer. 

The patented Ohio State syngas chemical looping process uses countercurrent moving bed reducer and oxidizer and iron-based composite oxygen carriers under reduction-oxidation conditions. In particular, the unit converts coal syngas, a mixture of carbon monoxide and hydrogen, to carbon-free energy carriers. The system is unique, as it can allow both electricity and hydrogen co-production as compared to other chemical looping technologies.

"Ohio State's chemical looping technology has the potential to secure coal and biomass as fuels for reliable, low-carbon domestic energy," said Eric Toone, the U.S. Department of Energy’s ARPA-E Deputy Director for Technology. "The collaboration between project participants at the National Carbon Capture Center holds great promise to accelerate the technology from demonstration into the marketplace."

According to Fan, the breakthrough was the production of pure hydrogen and carbon dioxide during the long-term, continuous sub-pilot demonstration. The production of pure hydrogen and carbon dioxide was achieved by a combination of the moving bed concept and the iron looping chemistry. By successfully demonstrating the moving bed idea, the iron looping process can achieve one of the lowest cost and most efficient technologies to produce affordable, pure hydrogen while attaining nearly 100 percent CO2 control and complying with all environmental regulations. 

Fan and his research team have conducted considerable research into chemical looping technologies, bringing these fundamental concepts closer to commercialization. It is projected that the syngas iron looping process will economically produce hydrogen for use as a feedstock in the petrochemical and chemical industries or as a gasoline, diesel, natural gas or fuel oil substitute.

Ohio State’s demonstration project will be the largest scale-up of the chemical looping gasification technology for hydrogen generation from coal. The project is co-funded by the U.S. Department of Energy/Advanced Research Projects Agency-Energy (ARPA-E) and the Ohio Department of Development’s Office of Energy through the Ohio Coal Development Office as well as industrial partners Babcock & Wilcox, CONSOL Energy Inc. and Clear Skies Consulting.

About The Ohio State University:
Recognized as Ohio’s best and one of the nation’s top-20 public universities, Ohio State’s main Columbus campus is one of America’s largest and most comprehensive, with more than 55,000 students in 14 colleges, 175 undergraduate majors, and 240 master’s, doctoral, and professional degree programs. The university’s total research expenditures in 2009 topped $716 million, ranking Ohio State 13th nationally, second in industry research, and ninth among public universities, according to the National Science Foundation.

About Southern Company:
A leading U.S. producer of electricity, Southern Company businesses include electric utilities in four states and a growing competitive generation company, as well as fiber optics and wireless communications.