Ohio State University engineers are in pursuit of an environmentally-benign process for exploiting fossil fuels, and report progress in economically converting these fuels and biomass into useful products without generating carbon dioxide emissions. Their coal-direct chemical looping (CDCL) combustion technique produces methanol, gasoline and other products, including electricity, while consuming CO2.

The technology, known as chemical looping technology uses metal oxide particles in high-pressure reactors The patented iron oxide particle used in the chemical looping process. Source: Jo McCulty / Ohio State UniversityThe patented iron oxide particle used in the chemical looping process. Source: Jo McCulty / Ohio State Universityto “burn” fossil fuels and biomass without the presence of oxygen in the air. The metal oxide provides the oxygen for the reaction.

Under certain conditions, the process consumes all the CO2 it produces plus more from an outside source.

The researchers first demonstrated CDCL technology five years ago, in which they were able to release energy from coal while capturing more than 99 percent of the resulting CO2. A key advance came in the form of iron oxide particles that supply the oxygen for chemical combustion in a moving bed reactor. After combustion, the particles take back the oxygen from air, and the cycle begins again.

These particles lasted through 100 cycles over more than eight days of continuous operation. Since then, a new formulation has been developed that lasts for more than 3,000 cycles, or eight months of continuous use in laboratory tests. The researchers note that this is the longest service life reported for the oxygen carrier.

Chemical looping has also been applied to the production of syngas, which in turn provides feedstock for diverse products including ammonia, plastics or even carbon fibers. The scheme provides a potential industrial use for CO2 as a raw material for producing useful, everyday products.

The Linde Group, a provider of hydrogen and synthesis gas supply and plants, has begun collaborating with the team. Efforts are underway to capture CO2 in hydrogen production plants and use it downstream to make products at a competitive cost.

Clean power technology developer Babcock & Wilcox Company is also working with Ohio State researchers to advance CDCL technology as an advanced oxy-combustion technology for electricity production from coal with nearly zero carbon emissions.

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