The College of Engineering Distinguished Seminar Series Presents
Chemical Looping Technology and CO2 Capture
L.- S. Fan, Distinguished University Professor
C. John Easton Professor in Engineering
Professor of Chemical and Biomolecular Engineering
The Ohio State University
Date: Wednesday, April 24, 2013, 10:30 - 11:45 am - Room S105 in Technology Hall
The concept of chemical looping reactions has been widely applied in chemical industries, e.g., the production of hydrogen peroxide (H2O2) from hydrogen and oxygen using 9,10- anthraquinone as the looping intermediate. Fundamental research on chemical looping reactions has also been applied to energy systems, e.g., the splitting of water (H2O) to produce oxygen and hydrogen using ZnO as the looping intermediate. Fossil fuel chemical looping applications had been used commercially with the steam-iron process for coal from the 1900s to the1940s and had been demonstrated at a pilot scale with the carbon dioxide acceptor process in the 1960s and 1970s. There are presently no chemical looping processes using fossil fuels in commercial operation. A key factor that hampered the continued use of these earlier processes for fossil energy operation was the inadequacy of the reactivity and recyclability of the looping particles. This factor led to higher product costs for using the chemical looping processes, compared to the other processes that were petroleum or natural gas based. With CO2 emission control now being considered as a requirement, interest in chemical looping technology has resurfaced. In particular, chemical looping processes are appealing due to their unique ability to generate a sequestration- ready CO2 stream while yielding high energy conversion efficiency. Renewed fundamental and applied research since the early 1980s has emphasized improvement over the earlier shortcomings. New techniques have been developed for direct processing of coal or other solid carbonaceous feedstock in chemical looping reactors. Significant progress is underway in particle design, reactor development, and looping system integration, as demonstrated by the operation of several pilot or sub-pilot scale units worldwide, making it possible that chemical looping technology may be commercially viable in the future for processing carbonaceous fuels.
This presentation will describe the fundamental and applied aspects of modern chemical looping technology that utilizes fossil and biomass as feedstock. The presentation will discuss reaction engineering and solids flow issues associated with this technology. Specifically, it will highlight reactions, reactors and solids-gas issues associated with the optimum feedstock conversion and relationship among the metal oxide conversion, solids flux and reactor configurations. Opportunities and challenges for chemical looping process scale-up and commercialization will also be illustrated.
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