Researchers at Ohio State University have developed a technology to make coal a cleaner energy resource. The technology has been tested at a pre-pilot scale, but will soon be taken to a larger-scale pilot plant with the U.S. Department of Energy’s National Carbon Capture Center in Wilsonville, Ala.
In September 2012, the research-scale clean coal combustion system produced heat from coal while capturing 99 percent of carbon dioxide emissions for 203 continuous hours (nine days). After over two years of research, the laboratory, run by Liang-Shih Fan, professor of chemical and biomolecular engineering and director of Ohio State’s Clean Coal Research Laboratory, has run the clean coal sub-pilot plants for a combined 830 operating hours, demonstrating the reliability and functionality of the technology.
The clean-coal technology is broken into two specific, but related sub-pilot technologies: Coal-Direct Chemical Looping (CDCL) and Syngas Chemical Looping (SCL). Both chemically harness the energy of coal and efficiently contains the carbon dioxide produced from the combustion of coal before it is released into the atmosphere through chemical reactions rather than combustion reactions.
Both technologies use readily available forms of coal, crushed coal and coal-derived syngas. At any one time, each unit produces about 25 thermal kilowatts of energy. Both units are located at the Ohio State Columbus campus.
At high temperatures, CDCL reacts metal beads of iron oxide and coal. The reaction binds the carbon from coal to the oxygen from the metal beads, creating CO2 molecules. The molecules rise in the reaction and are captured for recycling or sequestered for storage. The metal beads can be easily collected, re-oxidized, and used again.
Because nearly all of the carbon dioxide product is collected during the reaction, this technology exceeds the Department of Energy’s clean energy goals for new fossil fuel technologies, which requires new fossil fuel technologies should not raise the cost of electricity more than 35 percent and should capture more than 90 percent of carbon dioxide.
Source: New Coal Technology Harnesses Energy Without Buringin, Nears Pilot-Scale Development, Ohio State University Communications.