(228a) Chemical Looping Technology - a Particle Technology Perspective

The concept of chemical looping reactions has been widely applied in chemical industries. Fundamental research on chemical looping reactions has also been applied to energy systems. Fossil fuel chemical looping applications were used with the steam-iron process for coal from the 1900s to the1940s and were demonstrated at a pilot scale with the carbon dioxide acceptor process in the 1960s and 1970s. There are presently no chemical looping processes using carbonaceous fuels in commercial operation. A key factor that hampered the continued use of these earlier processes was the inadequacy of the reactivity and recyclability of the looping particles. This factor led to unsustainable operation of the process. With CO2 emission control now of great concern, interest in chemical looping technology has resurfaced due to their unique ability to generate a sequestration-ready CO2 stream.

Chemical looping technology is a manifestation of the interplay among all the key elements of particle science and technology including particle synthesis, reactivity and mechanical properties, flow stability and contact mechanics, gas-solid reaction engineering and particulates system engineering. This presentation will describe the fundamental and applied aspects of modern chemical looping technology that utilizes fossil and other carbonaceous feedstock. Specifically, it will discuss the reaction chemistry, ionic diffusion mechanisms, metal oxide synthesis and thermodynamics, reactor design, and system engineering along with energy conversion efficiency and economics of the Coal-Direct Chemical Looping Process and Syngas Chemical Looping Process being developed at Ohio State University at a pilot level. Further, CO2 emission control using the chemical looping technology will be illustrated and compared with other CO2 capture methods. Potential for selective oxidation in the production of fuels and chemicals, as well as solar based chemical looping technology, will also be discussed.