Available Technology

Metal Oxide Promoters for Improving the Reactivity and Capacity of Oxygen Carriers for the Chemical Looping Combustion Process

This technology, titled "Metal Oxide Promoters for Improving the Reactivity and Capacity of Oxygen Carriers for the Chemical Looping Combustion Process,” provides a mixed metal oxide carrier to improve the oxygen transfer capacity and reactivity of existing carriers. Following patent approval, the technology will be available for licensing and/or further collaborative research from the U.S. Department of Energy’s National Energy Technology Laboratory.
Abstract: 
Researchers continue to face the challenge of removing carbon dioxide (CO2) from power plants because existing methods to separate CO2from the gas mixtures require a significant fraction of the power plant output. Chemical-looping combustion (CLC) is a novel combustion technology that uses an oxygen carrier, such as metal oxide, to transport oxygen to the fuel thereby avoiding direct contact between fuel and air. The CLC process has the advantage of producing sequestration-ready CO2without the need for further separation required by conventional combustion technology whose streams are diluted by nitrogen (N2). Oxygen carrier development is very critical for CLC and iron oxide (Fe2O3) has commonly been used as an oxygen carrier in the past. However, the reactivity of Fe2O3-based oxygen carriers is insufficient for an industrial process. To address the above issue, this technology offers a mixed metal oxide carrier consisting of magnesium oxide (MgO) and Fe2O3(natural hematite) to improve the performance of oxygen carriers most often used in a chemical looping combustion reaction. The mixed metal oxide has a specific composition that exhibits superior reactivity and high oxygen carrier capacity over Fe2O3-based oxygen carriers and does not exhibit agglomeration after a multi-cycle operation. The preparation procedure of the novel oxygen carrier is very simple and uses readily available natural ores which will contribute to low cost. The attrition resistance of the novel oxygen carrier is similar to that of FCC catalysts. This technology has the potential for application to and enhancement of chemical looping systems, thereby providing several advantages to those systems, such as improved efficiencies over traditional single-stage combustion systems; oxidation-reduction reactions that occur at relatively low temperatures, allowing power stations to more closely approach optimum output; and effective carbon capture.
Benefits: 
Improves the rate of oxygen transfer and oxygen capacity of iron oxide (natural hematite) oxygen carriers most often used in chemical looping systems -Uses a mixed metal oxide carrier to exhibit superior reactivity -Significantly lowers the operating costs of chemical looping processes -Provides superior attrition resistance comparable to FCC catal -Overcomes problems associated with solely Fe2O3-based carriers insufficient for industrial processes
applications: 
Inventors: 
Ranjani Siriwardane
Patent Number: 
8,807,988
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